Final Report - Rercwm.pitt.edu - University of Pittsburgh

REHABILITATION ENGINEERING RESEARCH CENTER ON
Wheelchair Mobility
Douglas A. Hobson, Ph.D. and Clifford E. Brubaker, Ph.D.
Co-Directors
Final Report: 1993-98

ACKNOWLEDGEMENTS
Primary funding for the RERC was provided by the National Institute on Disability and
Rehabilitation Research, US Department of Education, Washington, DC (#H133E30005). Opinions
expressed in this report are those of the authors and should not be construed to represent opinions or
policies of NIDRR.
Additional student training support has been provided by NIDRR training grant to Dr. Rory Cooper
(H133P30002) and the RSA grant to Dr. Charles Robinson (H129E50008).
The University of Pittsburgh Medical Center has been most supportive in terms of providing
start-up faculty positions, office facilities and logistical support. Without this contribution, the notion
of competing for the Rehabilitation Engineering Research Center on Wheelchair Technology (RERC)
could not have materialized.
The task on manual wheelchair design (MM-1) was supported by a two year grant from the
Spinal Cord Injury Research Foundation of the Paralyzed Veterans of America (PVA).
We owe an ever increasing debt of gratitude to our community of collaborators. We extend our
sincere appreciation to clinicians, consumers, rehabilitation technology suppliers, manufacturers,
facility administrators and others who have volunteered their time and expertise in the interests of
improved wheelchair technology.
Finally, we wish to thank the members of our Advisory Board who have taken time from their
busy schedules to first learn about our plans and proposed activities, and then to provide feedback
and suggestions for improvement over the five years of the Center’s activities.
This final report was prepared under the direction of Douglas Hobson, Co-Director of the RERC
and its most significant editorial support from Jean Webb, Administrative Assistant and Ashli Molinero,
Communications Specialist. The final report is also available for full color viewingand downloading
from the RERC’s website: www.rerc.upmc.edu.

REHABILITATION ENGINEERING RESEARCH CENTER
ON WHEELCHAIR MOBILITY
FINAL REPORT:
SUMMARY OF ACTIVITIES
AUGUST 1, 1993-NOVEMBER 30, 1998
DOUGLAS A. HOBSON, PH.D.
AND CLIFFORD E. BRUBAKER, PH.D.
CO-DIRECTORS

ACRONYMS AND ABBREVIATIONS
AC................................ Alternating current
ANSI.............................American National Standards Institute
AT.................................Assistive Technology
ATBCB..........................Architectural and Transportation Barriers Compliance Board
CAT...............................Center for Assistive Technology
CG.................................Center of Gravity
DC................................ Direct Current
DOF..............................Degree of Freedom
DOT..............................Department of Transportation
DSP...............................Digital Signal Processing
EV..................................Electric Vehicles
ISO................................International Organization for Standardization
NHTSA........................National Highway Transportation Safety Administration
NIDRR.........................National Institute on Disability and Rehabilitation Research
PVA...............................Paralyzed Veterans of America
RERC............................Rehabilitation Engineering Research Center
RESNA.........................Rehabilitation Engineering and Assistive Technology Society of North America
SAE...............................Society for Automotive Engineers
USABC.........................United States Advanced Battery Consortium
W/C.............................Wheelchair
WMD............................Wheeled Mobility Device

TABLE OF CONTENTS
NIDRR Mandate ........................................................................................................................................................................ 1
Executive Overview.................................................................................................................................................................. 1
Summary of Tasks ..................................................................................................................................................................... 2
I. Wheelchair Technology Tasks ............................................................................................................................................. 4
Task PM-1: Improved Electric and Electromechanical Systems .................................................................................. 5
PM-1a: Computer Simulation of Electromechanical Systems.............................................................................. 5
PM1b: Power Wheelchair Batteries ......................................................................................................................... 7
PM1c: Power Wheelchair Controllers ..................................................................................................................... 8
PM1d: Improved Wheelchair Motor Drives ........................................................................................................... 9
Task PM-2: Advanced Mechanisms ............................................................................................................................... 11
Task PM-3: Input Devices and Control Concepts ........................................................................................................ 14
Task PM-5: The Use of Integrated Controls .................................................................................................................. 16
Task PM- 6: New Concepts In Powered Indoor Mobility ........................................................................................... 18
Task PM-7: Powered Mobility Simulator ...................................................................................................................... 26
Task MM-1: Structural Improvements to Manual Wheelchairs ............................................................................... 28
Task WP-1: Consumer-Responsive Mobility Prescription Process ........................................................................... 34
Task WP-2: Wheelchair Prescription Software Project (WPSP) ................................................................................. 36
Task STD-1: Participation in the Development of Wheelchair Standards................................................................ 38
II. Improved Wheelchair Seating........................................................................................................................................... 40
Task S-1: Cushion design for pressure ulcer prevention ............................................................................................ 41
Task S-2: Distortion measurement and biomechanical analysis of in vivo load bearing soft tissues .................. 44
Task S-3: Non-invasive Monitoring of Spinal/Pelvic Alignment.............................................................................. 51
Task S-4: The Effects of Positioning on Individuals with C5-C7 Quadriplegia ....................................................... 54
Task S-5: Customized Wheelchair Seating for Populations with Changing Needs................................................ 56
III. Improved Wheelchair Transportation ............................................................................................................................ 58
Task T-1: Criteria for Standards and Design of Wheeled Mobility Devices for use in Transportation Vehicles 59
Task T-2: Development of Wheelchair Securement Interface Concepts ................................................................... 62
Task T-3: Development of Docking Type Securement Devices .................................................................................. 68
Task T-4: Research and Coordination Related to Standards Development for Wheelchair Transportation ....... 76
IV. Training and Demonstration Activities .......................................................................................................................... 78
V. Dissemination and Utilization .......................................................................................................................................... 82
VI. People .................................................................................................................................................................................. 91

EXECUTIVE SUMMARY
The Rehabilitation Engineering Research Center
(RERC) on Wheelchair Mobility at the University of
Pittsburgh officially began on August 1, 1993. The fiveyear
award officially ended on November 30, 1998.
This final report summarizes research, training and
information dissemination activities of the RERC and
highlights the outcomes of the five-year effort.
First, it is important to understand the mandate
under which all RERCs have been authorized and,
then more specifically, the absolute priorities that
directed the efforts of the RERC on Wheelchair
Mobility since 1993. The RERC program is sponsored
by the National Institute on Disability and
Rehabilitation Research (NIDRR) of the Department
of Education, Washington, DC.
NIDRR Mandate
All RERCs receiving support from NIDRR have
common requirements which include:
♦ participation of consumers, service providers,
equipment manufacturers and others with
relevant interest in the prospective research
activities,
♦ provision of graduate level training to develop
capacity for research in rehabilitation engineering
and assistive technology,
♦ dissemination of information and materials
generated by RERC efforts in accessible formats,
♦ sharing information and working with other
organizations, industry, service providers, other
RERCs and particularly the RERC on Evaluation
and Technology Transfer, and
♦ evaluation of materials and products of the RERC
and other researchers in an effort to foster effective
transfer of technology.
Obligations for the RERC on Wheelchair
Technology that were evident from the statements of
“absolute priorities” issued by NIDRR include the
development and demonstration of technologies to:
♦ improve the mobility of individuals using
powered wheelchairs (W/C) by developing more
efficient, reliable, and maintainable W/C systems,
♦ improve the mobility of W/C users by developing
W/Cs that are stronger, lighter in weight, and
easier to manufacture and maintain,
♦ enhance the safety and mobility of W/C users by
developing safe vehicle securement systems for
various types of wheelchairs and various types of
vehicles, especially those used in mass transit, and
♦ enhance the function of W/C users by developing
improved seating systems and interfaces with
environmental controls and other devices for daily
living activities.
The priorities further require the RERC to identify
criteria and support standards for W/C performance
and vehicle securement in coordination with the US
Department of Transportation (DOT) and the
Architectural and Transportation Barriers Compliance
Board (ATBCB).
Objectives of the RERC on Wheelchair Mobility
The overall goals of the RERC can be stated in two
encompassing objectives:
1. elevate the state-of-the-art technology and
knowledge relevant to W/C mobility, seating, and
transportation to the highest possible level, and
2. disseminate and transfer this state-of-the-art
knowledge and technology to a state of practice
that results in optimum utilization of this
technology and knowledge by persons with
disabilities.
Summary of Tasks
The University of Pittsburgh and its collaborators
initiated 27 interrelated tasks over five years grouped
across four priority areas: wheeled mobility,
wheelchair seating, wheelchair transportation safety,
and training and information dissemination (see the
following tables for a summary of the tasks).
cription
Final Report: 1993-1998
1

Table I. RERC Research Tasks
Wheeled Mobility Tasks Tasks
PM-1 Improved Electric and Electromechanical
Systems
PM-2 Advanced Materials and Mechanisms
PM-3 Improved User Input Devices and Control
Concepts
PM-4- Integration of Improved Mobility
Components
PM-5 The Use of Integrated Controls by Persons
with Physical Disabilities
PM-6 New Concepts in Powered Indoor Mobility
PM-7 Powered Mobility Simulator
MM-1 Structural Improvements to Manual
Wheelchairs
WP-1 Consumer-Responsive Mobility Prescription
Process
WP-2 Wheelchair Prescription Software Project
Descriptions
Descriptions
Developments in batteries, power controllers and motors
Developments in frames, steering mechanisms and
suspensions
Developments in standard interfaces, input devices and
controllers
System simulation and product specification and design
Investigation of the use of integrated controls
Development of novel indoor powered mobility devices
Development of a low cost tool to allow consumer
experimentation with powered mobility options prior to
purchase
Development of improved manual wheelchair frames
Development of consumer-responsive mobility
prescription process
Development of a computer-based program to provide
training in strategies of wheelchair prescription
STD-1 Research in Support of Wheelchair
Standards
Seating Tasks
Support of the development of W/C standards through
laboratory research
Descriptions
S-1 Cushion Design for Pressure Ulcer Prevention To develop systematic techniques necessary to improve
the quality and consistency of CAD/CAM cushions
producing technology
S-2 Distortion Measurement and Biomechanical
Analysis of Invivo Load-Bearing Soft Tissue
S-3 Non Invasive Monitoring of Spinal /Pelvic
alignment
S-4 Effects of Seating on Individuals with
Quadriplegia
S-5 Customized Wheelchair Seating for
Institutional Populations with Changing Needs
To validate or invalidate the use of external pressure as an
indicator for harmful internal strain in soft tissue
To research, develop and evaluate a non-invasive clinical
tool for monitoring changes in spinal/pelvic alignment
over time
To investigate the effect of W/C seating on the postural
status, pulmonary function, and upper extremity function
of individuals with SCI at the C5 to C7 level
To develop criteria and prototype mobility and seating
assemblies to meet the needs of residents in institutions
whose needs are constantly changing
2 RERC on Wheelchair Technology

Transportation Tasks
T-1 Criteria for Standards and Design of
Transport Wheeled Mobility Devices for Use in
Transportation Vehicles
Descriptions
To develop design criteria that can be used for both the
development of national standards, as well as in the design of
transport WMDs that meet the standard
T-2 Development of Standard Interface Concepts To develop and evaluate universal interface hardware concepts
that will assure compatibility between WMDs and securement
devices
T-3 Development of Auto-engage Securement
Devices
To develop, test and commercialize a series of auto-engage
securement devices that are based on universal design standards
T-4 Research in Support of National Standards To provide direct research support to standards development,
and advocate for adoption of universal interface concepts
resulting from Tasks 1, 2 & 3 into national and international
standards
In addition to the eighteen research and development tasks, the RERC is mandated to conduct activities
in training and dissemination. Table II summarizes the seven tasks associated with these activities.
Table II. RERC Training and Dissemination Tasks
Training Tasks
TR-1 Graduate Education
TR-2 Student Research Training
TR-3 Continuing Education
TR-4 Consumer Training
Dissemination Tasks
DU-1 Dissemination of RERC Research
Findings
DU-2 National Information Center
DU-3 Technology Transfer
Descriptions
To increase the numbers of qualified professionals in assistive
technology through support of formal educational experiences
To provide students with mentored research experiences in the areas of
wheeled mobility and related research
To enhance post service skills through supporting continuing education
experiences for practicing professionals and others
To provide opportunities for users of technology to become more
knowledgeable in AT research and applications
Descriptions
To disseminate the outcomes and findings of the RERC research tasks
using multiple venues
To disseminate a wide range of information on wheeled mobility via an
information concept
To facilitate the transfer of RERC Center and other research
developments through affiliations with others, including industry
The body of the report provides only a brief description of each research task, a summary of each task
outcomes and recommendations for future work. Many tasks have generated publications or technical reports
that are referenced at the end of each task report. A complete listing of all publications appears in Section V
– Dissemination and Utilization.
Final Report: 1993-1998
3

I. WHEELCHAIR TECHNOLOGY TASKS
♦PM-1 Improved Electric and Electromechanical Systems
♦PM-1 a Computer Simulation Electromechanical Systems
♦PM-1 b Power Wheelchair Batteries
♦PM-1 c Power Wheelchair Controllers
♦PM-1 d Improved Wheelchair Motor Drives
♦PM-2 Advanced Materials and Mechanisms
♦PM-3 Improved User Input Devices and Control Concepts
♦PM-4 Integration of Improved Mobility Components (removed from work program)
♦PM-5 The Use of Integrated Controls by Persons with Physical Disabilities
♦PM-6 New Concepts in Powered Mobility
♦PM-7 Powered Mobility Simulator
♦MM-1 Structural Improvements to Manual Wheelchairs
♦WP-1 Consumer Responsive Mobility Prescription Process
♦WP-2 Wheelchair Prescription Software Project
♦STD-1 Research in Support of Wheelchair Standards
4 RERC ON WHEELCHAIR TECHNOLOGY

TASK: PM-1 IMPROVED ELECTRIC AND
ELECTROMECHANICAL SYSTEMS
Approach and Background
The research approach taken was to address each
of the major electromechanical components of the
powered wheelchair independently within Tasks PM-
1-3. Task PM-4 was intended to integrate the
component results into a complete ‘idealized’ system.
Task PM-1 investigates each of the major drive system
components (batteries, controller, motors, and power
train) as interrelated sub-tasks.
The four sub-tasks of PM-1 are as follows:
PM-1a Electromechanical System Simulation
PM-1b New Technology for Wheelchair Batteries
PM-1c Improved Power Controllers
PM-1d Improved Wheelchair Motor Drives
The initial two years of the Task PM-1 involved a
major subcontract with Westinghouse Corporation.
Unfortunately, Westinghouse has undergone
significant downsizing and restructuring which has
lead to a reduction in resources (staff and laboratories)
that were initially available to this task. Progress was
impeded by this unforeseeable event as new resources
had to be identified and new team members brought
up to speed during Year III. By the end of Year III,
most collaborative work with Westinghouse had been
terminated and other resources identified.
PM-1ACOMPUTER SIMULATION OF
ELECTROMECHANICAL SYSTEMS
Investigators: Douglas Hobson, Dave Brienza, Fazal
Mahmood, Jonathan Evans
Rationale
Designers of powered wheelchairs have few tools
to assist in the design and development of new
powered wheelchairs. This task focuses on the
development of a computer simulation tool that can
aid designers during the decision-making process
regarding the selection of various electromechanical
components. The primary strategy is to optimize the
design towards the lowest energy consumption.
Other variables, such as tipping stability, can also be
optimized.
The initial thrust of this task was to model the
components of the wheelchair using a proprietary
simulation tool (HEAVY) developed by
Westinghouse, Inc. When it became evident that the
Westinghouse tool was not appropriate for
wheelchair simulation and considerable new code
would be required, the task was scaled back to focus
on a more limited design tool for industry. This
direction was taken at the advice of our Advisory
Board at its May 1995 meeting.
Goals
To develop a computer-based design tool to
facilitate the design of powered wheelchairs for use
by wheelchair designers.
Methods Summary
A computer program called HEAVY, originally
developed by Westinghouse Inc. when it was
involved in battery powered car research, was used
as the conceptual model for the simulation program.
Many algorithms had to be modified and others
added to make the model applicable to wheelchairs.
The original program was Fortran based therefore not
readily useable by desktop computers. Prior work
done at the University of Virginia-RERC on rolling
resistance, wind drag and power consumption was
used to make the model more applicable to
wheelchairs. Comments were solicited from industry
designers regarding the desirable outcomes of the
model. Once the simulation model was completed,
validation by actual wheelchair testing using a
prescribed test course was done to check the accuracy
of the simulation model. Refinements to the
FINAL REPORT: 1993-1998
5

simulation tool was done over time by continued
validation testing using different types of
wheelchairs.
Outcomes Summary
Conversion to C ++ code for the simulation
program was completed. The simulation program
now includes program code to carry out the
simulations as illustrated in the following flow
diagram. First stage validation of the simulation was
completed. This was done using an on-board data
measurement/collection system while driving two
production wheelchairs through a prescribed test
course. Energy consumption was measured and
compared to the simulation results.
In order to verify the accuracy of the energy
consumption model, two powered chairs were
monitored while they completed the test track
outlined in the ISO standards (ISO 7176/6) for
determining the energy consumption and range of
powered wheelchairs. Our test course covered 200
feet with the dimensions of the rectangular track
measuring 50 feet on each side. Throughout the test,
Since we were unable to obtain the specific motor
and battery characteristics for the wheelchairs that
were tested, the program used data obtained for
motors and batteries with similar characteristics.
However, due to the power capacity of the Invacare
chair tested, the characteristics were thought to be
sufficiently different to effect the results of the
simulation program. Therefore, only the results from
the Quickie P-190 are were used.
For the Quickie P-190, the measured average
speed over the ISO test track was 5.67 ft/ second. The
distance traveled was 2000 ft. and the energy
consumed was 22.7 watt-hours. By using the ISO
guidelines for determining the range of the chair, the
range for the P-190 was determined to be 6.67 miles.
For the simulation, the motor data that was used
was the Fracmo M453-W30 24-volt DC motor. The
battery data was based on the MK 22NF Gel Battery.
Using the speed of 5.67 ft/sec. as input data, the
program then calculated the drag, the gear-box losses
and the air drag to determine the torque required to
overcome these losses at the specified motor RPM.
The drag losses calculated for P-190 was 35.5 pounds.
The wheel diameter is 12.5 inches; therefore, the
User Input Variables
Specifications:
• weights
•W/C • type
•wheelbase
•
•c.g. • location
•wheel • diams.
•battery • type
•motor • type
•drive • efficiency
•surface • type
•rolling • coeffs.
Processing
Computes:
• the range based
on energy capacity of
specified battery and
drive cycle
•static • ability
•maneuverability
•
•maximum • velocity
Output Data
Specifies:
• range (miles)
•static•
ability
•maneuverability•
•maximum•
velocity
•total•
efficiency
Figure 1 - Flow diagram of simulation process
the voltage and current were recorded using a lap
top computer, which acquired readings 200 times per
second. The results of the validation were then used
to compare the results obtained when running an
identical course in the computer simulation model.
torque required to overcome these losses is 221.9 in./
lb. Use the look-up tables for the motor
characteristics, the available energy of the battery is
monitored at each 1-second interval in order to
determine the range. From the simulation, the energy
6 RERC ON WHEELCHAIR TECHNOLOGY

used while driving through the virtual ISO test course
was 52.86 watt-hours, yielding a total range of 3.86
miles.
The results of the simulation program vs. the
validation test show that the computer model
computes a range 42% less than the actual measured
results. This difference makes the use of the
simulation program impractical at its present stage.
More work is required to determine the source of
error.
It seems that the method used for determining
the drag may be incorrect. From studying how the
air, motor, and rolling drag are calculated, it appears
that the rolling resistance equations yield a larger
value than expected (32 lbs.). Accurate battery and
motor characteristics are also necessary for precise
comparative validation. Also, the effects of caster
drag, even on a firm rectangular test course, are not
adequately addressed by the simulation model. If
these deficiencies can be corrected, it appears that the
computer model can be a useful tool in studying the
effects that different batteries, motors, mass and frame
and wheel configurations have on the range and
energy efficiency of powered wheelchairs.
Recommended Future Research and Development
The C ++ code for the simulation program
functions as intended. Additional experimental work
must now be done to refine the algorithms in order
to reduce the disparity between actual and simulated
values. Initial C++ code work was also done on the
modeling for static stability. However, now that the
newly revised versions of the ISO standards for static
(Part 1) and dynamic stability (Part 2) tests have been
completed, these simulations could be added to the
battery of tests. All information on the above
algorithms, program code and energy consumption
testing will be maintained on file, at least until
January 2003. This information can be made available
to any persons seriously contemplating additional
development of this simulation tool.
Publications
Alva, P and Hobson, DA, Computer simulation of powered
wheelchair electro-mechanical systems, Proceedings of the
RESNA ‘96 Annual Conference, Salt Lake City, UT, June 1996
Hobson DA (in preparation)
PM-1B POWER WHEELCHAIR BATTERIES
Investigators: David Brienza, Douglas Hobson,
Mostafa Khondukar
Collaborators:Rick Blanyer, Steve Addington
(Electrosource, Inc.)
Rationale
The key component in any electrically powered
vehicle is the battery—the heaviest, most expensive,
and least reliable system component. The need for
improved battery technology is clear. Current
technologies used and the configurations made
available are far less than optimal for wheelchair
applications. For example, the basic configuration of
lead-acid batteries [Bode, 1977] limits frame design,
space for respirators, etc. Virtually every commercial
electric vehicle, including wheelchairs, uses a leadacid
battery. For many years, lead-acid has been the
most reliable, cost-effective, and practical battery
available. It exists in its present form due to the
billions of dollars worth of research and development
aimed at improving both the battery and the mass
production process. These efforts, which were fueled
and funded almost entirely by the automobile
industry, have led to the optimization of a lead-acid
battery with respect to economics and the task of
starting a car engine. For application in wheelchairs
[Kauzlarich, 1990; Petersen, 1986; Lavanchy, 1992], the
lead-acid battery is much less than ideal. It is heavier,
more costly, and less reliable than desired, which is
not a surprising situation considering the fact that
the lead-acid battery was not originally engineered
and developed for motive power applications.
Project Goals
Our objectives for this task were:
• Review current and developing battery
technology and evaluate its efficacy for use in
powered wheelchair systems,
• Identify one or more candidate battery
technologies, acquire prototypes and evaluate
performance relative to wheelchair applications,
and
• Disseminate findings and facilitate technology
transfer to wheelchair manufacturers.
FINAL REPORT: 1993-1998
7

Methods and Outcomes Summary
A comprehensive review of emerging battery
technology was completed and published as an RERC
Technical Report No. 2 (Bayles, 1995) and presented
at a national RESNA Conference (Bayles et al., 1994).
As a result of that effort, one candidate battery
technology was selected to evaluate for possible
application in powered wheelchairs. That
technology—the Horizon® battery—is an advanced
lead-acid technology developed by Electrosource, Inc.
of Austin, Texas. The Horizon battery is shown along
side a standard 22NF lead-acid battery in Fig. 2.
Although other technologies were considered, the
Horizon® was selected as the best battery available
for evaluation. The potential advantages are
improved energy density, improved specific energy
and a low profile design. A test plan including bench
testing and dynamometer testing was developed. The
load cycle used for testing is a variable discharge cycle
and is intended to be representative of typical indoor
and outdoor wheelchair driving. Bench testing has
been completed. Compared to commercially available
22NF gel electrolyte, lead-acid batteries, the Horizon®
battery demonstrated a 74% increase in specific
energy (40.6 Wh/kg vs. 23.3 Wh/kg).
A meeting was organized, including technical and
marketing staff from Electrosource, representatives
from three major wheelchair manufacturers, a
representative from one scooter manufacturer, and
the RERC staff was organized. At the meeting an
introduction to the new technology and preliminary
test results were shared. The research staff has no
knowledge of any further communication between
Electrosource and the wheelchair manufacturers.
Recommended Future Research and Development
Development of new battery technology has been
progressing more slowly than was anticipated in
1993. However, we expect that significant
improvements will be achieved. For this reason,
wheelchair industry representatives are advised to
stay informed and in the development loop so that
the specific requirements of the power wheelchair
may be accommodated in the packaging of any new
and significant battery technology.
Figure 2 - Horizon (right) and standard 22NF (left)
lead-acid batteries
Publications
Bayles, G. New Power Source Technologies for Electric
Wheelchairs, Technical Report #2, RERC, University of
Pittsburgh, Pittsburgh, PA 1995.
Bayles, G., Ulerich, P., Palmer, K., and Brienza, D.M., New
Battery Technology for Powered Wheelchairs, Proceedings
of the 17th Annual RESNA Conference, Nashville, TN, June
1994.
References
Bode, H., Lead-Acid Batteries, John Wiley & Sons, NY, 1977.
Kauzlarich, JJ. Wheelchair batteries II: Capacity, sizing, and
life, J Rehab Res and Devel, 1990; 27(2):163-70.
Lavanchy, C. Comparative evaluation of major brands of
lead-acid batteries, Proceedings of the 1992 RESNA
International Conference, 1992;pp.541-43.
Peterson. HA. Development of test procedures for batteries
in electric wheelchairs, Report No. 86022, Energy Research
Laboratory, Niels Bohrs Alle 25, 5230 Odense M, Denmark.
PM-1C POWER WHEELCHAIR CONTROLLERS
Investigators: David Brienza and Wonchul Nho
Collaborators:Theodore Heinrich (Westinghouse
Inc.)
Rationale and Goals
Very little innovation has occurred in the
methodology used to control the power from the
batteries to the motors, which is the job of the power
controller. The objective of this development task was
to adapt an alternating current (AC) motor controller
8 RERC ON WHEELCHAIR TECHNOLOGY

technology developed for an electric automobile for
use in a wheeled mobility device.
Methods and Outcomes Summary
An AC power controller using the vector control
technique was designed. An existing design
produced by the Westinghouse Corporation for
electric vehicles (EV) was modified and updated to
fit specifications developed for powered wheelchairs.
The vector controller consists of two portions,
software and hardware. Our initial work on this task
concentrated on the hardware dedicated to the high
current output stage of the controller, the motor drive.
The role of the motor drive is to convert stored energy
in the batteries to electrical power for the motors
according to the magnitude of a control signal
generated by the controller section of the device. A
block diagram of a typical electric wheelchair power
train is shown in Figure 3 below. The design for the
power controller has been completed. The new design
of the motor drive has been enhanced as compared
to the original EV design. The power switching
integrated circuits were upgraded using IGBT devices
and important performance gains were achieved with
the addition of a dead-time generator.
The design of the dead-time generator in the
motor drive has involved the theoretical
determination of three important parameters: carrier
ratio, modulation index, and time-delay. Depending
on the values and combinations of values of these
parameters, harmonic and wave form distortions can
be significant or negligible. The effect of the
significant distortions is a reduction in efficiency and
a momentary loss of control. Distortions in the
voltage-wave form have been investigated through
simulation. Distortions were determined as a function
of carrier ratio, modulation index, and time-delay.
Optimal values that minimize the distortion for both
fundamental and harmonic components of the
voltage-wave form in the output of the motor drive
were selected for three representative operating
conditions. The results of the simulation indicate that
the modulation index must be near unity, carrier
frequency is good at 15 kHz and a time delay of 10
msec is adequate. The application of these optimal
values should allow for significant improvement in
the output wave form of the motor drive.
Original plans for this task included the
fabrication and testing of a prototype controller; these
plans were not executed.
COMPUTER
INPUT
DEVICE
(JOYSTICK)
DRIVER
CONTROLLER
BATTERY
MOTOR
DRIVE
MOTOR
DRIVE
Figure 3 - Schematic of the prototype controller
Publications
Nho WC, Brienza DM and Boston R. The development of
and AC motor drive in power wheelchair Proceedings of
15th Annual RESNA Conference, Salt Lake City, Utah, June
7-12, 1996.
PM-1D IMPROVED WHEELCHAIR MOTOR
DRIVES
Investigators: Douglas Hobson, David Brienza
Collaborator: Jules Legal
Rationale
Advancement of powered wheelchair options is
restricted by the availability of motor drive
configurations. This task explored motor
developments and specifically, motor/drive
combinations that will open new opportunities for
alternate wheelchair designs.
This task initially focused on the potential use of
AC motors and the improvement of DC motors.
However, it quickly became evident that the size of
the wheelchair market limits the development of new
motor technology specifically for use in the
wheelchair industry. Therefore, the focus was
redirected to identify existing technologies that can
be “re-packaged” in such a manner to offer new drive
options, such as a steerable in-hub motors and gear
train combinations.
IM
IM
FINAL REPORT: 1993-1998
9

Project Goals
1. To improve the availability of alternate wheelchair
motors/drive systems through forming working
partnerships with Federal labs and/or motor/
gear drive developers and manufacturers,
2. To work with wheelchair manufacturers in
evaluating the feasibility of introducing new
motor/train concepts and devices into new
wheelchair designs.
6.000
Rearch and Development
As will be discussed in Project PM-6 below, the
commitment of a motor development and
manufacturing company will be necessary before any
new significant motor drive options will be made
available to the wheelchair industry. As part of the
PM-6 continuation plans, SBIR funding will be sought
to allow active participation by a motor company and
a wheelchair manufacturer in this effort to provide
alternate drive systems for indoor power wheelchairs.
4.000 4.375
Encoder
Steering motor
Drive motor
3.500
4.500
Motor mount
Timing belt
Clutch actuator
1.500
1.000
Dual drive wheels
6.000
Figure 4 - Schematic of powered steering for front wheel
drive wheelchair
Outcomes Summary
Information and supplier literature was collected
on available motors and gear drives, such as the
Fracmo line. Direct communication was established
with Fracmo, which was followed by a joint meeting
with the Pitt-Westinghouse team in November 1994.
As a result, several prototype motor drives were
obtained and used in tasks PM-2 and PM-6. A
conceptual design was prepared and sent to a list of
manufacturers with the goal to identifying a firm that
wished to pursue a joint development project. The
same specifications were distributed throughout the
NASA technology transfer network in an effort to
identify new sources of motor/drive technology.
Finally, the following conceptual drawings were
prepared, complete with more detailed views and
specifications on the operational characteristics
required. These drawings and their contained
specifications will be used for future communications
with prospective motor/drive manufacturers.
10 RERC ON WHEELCHAIR TECHNOLOGY

Rationale
Powered wheelchair maneuverability is critically
important to many people that need to maneuver their
wheelchair in confined spaces. Most products today
use the same control strategy that was used in the
first powered wheelchair introduced by Everest and
Jennings in the mid 1950s. It relies on the independent
control of the two powered wheels, usually in the rear,
and the free motion of pivoting front caster wheels.
This task and PM6 are investigating alternate methods
for enhancing wheelchair maneuverability by
changing the fundamental manner is which the
steering is accomplished. Application of successful
findings to future products will increase the number
of environments accessible to persons using these
products.
The ability of a powered wheelchair user to
maneuver in tight spaces is closely related to the
chair’s drive and steering configuration. The most
common drive configuration, differential rear wheel
drive, consists of fixed and driven rear wheels with
front caster wheels. Direction changes are made by
individually varying the speeds of the rear wheels.
In this configuration the point about which the
wheelchair pivots lies on the line perpendicular and
running through the center of the rear wheels. The
minimum turning radius is achieved when the pivot
point is directly between the rear wheels. The
minimum space required to turn the wheelchair is
then determined by the maximum distance from that
point to any other point on the wheelchair. This is
usually the front corner of the footrests or the user’s
feet (Figure 5).
To minimize the turning radius for the rear wheel
differential drive configuration, the point between the
rear wheels must be located as close to the geometric
center of the chair as possible. Several commercially
available power chairs have achieved reduced turning
radius using this approach. Another benefit of this
approach is that a larger portion of the total weight
FINAL REPORT: 1993-1998
TASK: PM-2 ADVANCED MECHANISMS
Investigators: Clifford Brubaker, David Brienza, Douglas Hobson
Collaborators: Jules Legal, Edmund LoPresti
11
of the wheelchair is born by the drive wheels and
less by the caster wheels. The more weight there is
on the caster wheels, the more difficult it becomes to
change directions when caster wheels must reverse
directions and rotate through 180°. The approach,
however, causes the designer to take extraordinary
steps to provide stability. Typically, stability is
achieved by counter balancing the user’s mass over
and in front of the main drive wheels with the center
of mass of the batteries located approximately at or
just rear of the axis of the main drive wheels. It is
often necessary to provide anti-tip wheels in the rear
of the chair to avoid tipping backwards while
accelerating forward. The addition of these extra
wheels may compromise the chairs ability to climb
over low obstacles if the wheels are small or close to
the ground.
Figure 5 - Rear wheel differential drive configuration
Methods Summary
front
caster wheels
in front
fixed drive
wheels
in rear
pivot point for
minimum
turning radius
An alternate approach to minimizing the turning
radius is to steer all four wheels. Steering all four
wheels avoids the problems associated with caster
wheels yet retains minimum turning radius,
maximizes stability, provides tracking of the front and
rear wheels along the same path, and provides for
enhanced obstacle climbing capability.

The challenge in designing a mechanical fourwheel
steering mechanism is to design a device with
the ability to turn each wheel through 180° while
minimizing misalignment of the wheels. Steering
linkages such as those used in automobiles owe their
simple design to the relatively small turning angles
required by that type of vehicle. For highly
maneuverable small vehicles such as wheelchairs, the
range of steering angle is much greater. Furthermore,
the wheels must maintain proper alignment over the
entire range of steering angles to avoid undesirable
wheel scrubbing when the wheelchair turns. The
wheels are properly aligned whenever the
perpendicular bisectors of all four wheels intersect
at a single point. In four wheel steering, this point
lies on a line between the front and rear wheels
running perpendicular to the fore-aft direction of the
base. This is illustrated in Figure 6. In two wheel
steering, the perpendicular bisectors of the front
steered wheels intersect at a point along the line
through the centers of the fixed rear wheels (Figure
5).
typical pivot
point
front
pivot point for
minimum
turning radius
Figure 6 - Wheel alignment for four wheel steering about a
single pivot point
Outcomes Summary
A photograph showing a section of the
prototype steering linkage is shown in Figure 7.
A working platform that can demonstrate the
potential of the four-wheel drive configuration was
completed but the testing remains to be completed.
Recommended Future Research and Development
Future research and development should begin
by investigating the control issues concerning the
operation of a four wheel steered wheelchair. The use
of four wheel steering in the wheelchair application
introduces a dilemma for the control of that vehicle.
Optimum performance is likely attained when the
wheels can be left at arbitrary, but a known, steering
angle while the wheelchair is idle. Under these
conditions the driver knows which direction the chair
will initially go and there is no delay in initiating a
move. However, to make the direction of the wheels
known to the driver while the chair is at rest requires
the driver to observe the direction using a visual
inspection of the wheels or the direction information
Figure 7 - The complete linkage consists of two sliding
members (A), four cam follower slots (B) cut into a flat plate
(C), and two links (D) for each wheel.
must be provided using some other feedback
mechanism. Three options come to mind: 1) a visual
display on the controller panel; 2) tactile feedback
through the control stick using a rotation about either
the unused vertical axis or a rotation about the
steering axis; 3) no feedback at all. Although no
solution is ideal, a rotation of the stick seems more
desirable from the users perspective because it will
not require the driver to read a display, thereby
diverting his or her attention away from the
surrounding environment. The rotation option is
12 RERC ON WHEELCHAIR TECHNOLOGY

likely more complex and expensive to implement. The
third option, no feedback at all, will require the driver
to sense the wheel direction by sensing the direction
of travel once motion is initiated; this option is likely
to be problematic in confined spaces where the chair
is close to obstacles.
The other alternative for control of the vehicle is
to program the controller to self-center the wheels
each time the chair stops. This solution is also less
than ideal. In this configuration, there will be a delay
between the time when the user steers the wheels and
when the chair is able to travel in the desired
direction. If there is no direction feedback for the
wheels, the user is required to perform a visual
inspection of the wheel direction or sense the direction
after initiating a move by observing the direction of
travel.
Publications
Brienza, DM and Brubaker, CE. A four-wheel steering
mechanism for short wheelbase vehicles. Proceedings
RESNA Annual Conference, Pittsburgh, PA, June 1997
Brienza DM and Brubaker CE. A steering linkage for
short wheelbase vehicles:Design and evaluation in a
wheelchair power base. Journal of Rehabilitation Res &
Dev.1999;36(1)
US Patent No. 5,862,874.
FINAL REPORT: 1993-1998
13

TASK: PM-3 INPUT DEVICES AND CONTROL CONCEPTS
Investigators: David Brienza, Wonchul Nho, James Protho, Patricia Karg,
Jennifer Angelo and Kimberly Henry
Rationale
The interface between the wheelchair user and
the wheelchair itself is often the most critical
component of the powered wheelchair. Hand
operated joysticks with proportional control are now
the traditional method of interface for most
wheelchair users. Sip and puff control, head control,
chin control, single switch are further options for
those that are unable to access the joystick.
Goals
The objective of this task was to review existing
input and controller technology and explore technical
options for enhanced performance, reliability and
safety given current market needs and the evolving
national standards for microprocessor-based
wheelchair controllers.
Methods and Outcomes Summary
The results of a focus group meeting to identify
the most significant issues impacting input devices
and control concepts for powered mobility devices
held during the first funding period has been reported
(Brienza, et al, 1995).
A research and development plan consistent with
the needs identified by the focus group and
compatible with the goals and objectives of the RERC
was conducted. The long-term goal of this research
is to develop a control system that integrates
navigational and obstacle detection sensors into a
control system that assists the driver of a wheelchair
in both known, i.e., mapped, and unknown
environments. Potential applications of the system
include obstacle avoidance in known and unknown
environments, execution of predefined maneuvers
such as traversing through a doorway or following
along a wall, assisted navigation along predefined
paths through a known environment and as a driving
skills training device for powered wheelchair users.
Developments during the first project period
concentrated on the application of assisted obstacle
avoidance using a force feedback joystick. During the
second period the two control algorithms were
further developed.
Two philosophies have guided the design process:
1) ultimate control of the wheelchair must remain
with the driver and not with the control algorithm;
and, 2) mobility efficiency must be maximized.
Providing the user with the ability to apply the
decisive control input signals distinguishes this
wheelchair control system from that of an
autonomously guided vehicle. The driver remains in
control of the decision making element of the system
and at no time is an action initiated without allowing
the user to override the suggested action. Also, any
input action should result in a predictable response
from the system so that the user is not required to
decipher the control algorithm in order to accomplish
a desired task.
The object of the control system is to assist the
driver in negotiating obstacles as fast as possible and
with as little cognitive and physical effort as possible.
It is undesirable to slow down the wheelchair. This
would decrease efficiency or burden the driver with
excessive monitoring tasks, making the wheelchair
more difficult to drive. Instead our objective is to
influence the steering of the wheelchair using force
feedback from the active joystick. Note, however, that
the user may choose to counter the suggestions of
the control system by overcoming the joystick’s force
resistance.
Since the conceptual development of these control
modalities, this task concentrated on implementation
of a system for the evaluation of the concept.
An evaluation of a force feedback joystick for a
powered wheelchair was performed. The study aim
was to determine if the device enhanced the driving
performance of experienced wheelchair users. A
prototype device was constructed and used with a
virtual reality system for the evaluation phase of the
14 RERC ON WHEELCHAIR TECHNOLOGY

study. The force feedback joystick is shown in Figure
8. Test subjects used the force feedback joystick as a
prototype to navigate a wheelchair through a virtual
environment with and without the force feedback
algorithm activated (Figure 9). According to the
position of the wheelchair in the virtual environment,
the force feedback algorithm changed the compliance
of the joystick making it more difficult to move the
joystick in the direction of an obstacle. The factors
that were used to determine the compliance of the
joystick were 1) the angle between the wheelchair
velocity vector and the displacement vector of the
closest obstacle, and 2) the speed of the wheelchair.
The subjects were experienced power wheelchair
users with marginal ability to control a wheelchair
using a conventional proportional joystick. Their
performance using the force feedback joystick was
measured using the time needed to complete a run
through the course and the number of collisions with
the obstacles. The test course is shown in Figure 10.
The results showed that one out of the five subjects
who participated in the study had fewer collisions
when the force feedback algorithm was activated
compared to their performance when the algorithm
was not activated.
Figure 9 - Picture of a subject using the system
Figure 10 - Diagram of test course.
Publications
Brienza, D.M., Angelo, J.A., Henry, K. Consumer
participation in identifying research and development
priorities for power wheelchair input devices and
controllers. Assistive Technology, July 1995.
Figure 8 - Picture of force feedback joystick
FINAL REPORT: 1993-1998
15

TASK: PM-5 THE USE OF INTEGRATED CONTROLS BY
PERSONS WITH PHYSICAL DISABILITIES
Investigators: Jennifer Angelo and Elaine Trefler
Rationale
Persons with limited motor abilities and multiple
technical needs are able to access assistive
technologies through either many individual
switches or integrated controllers. There are no
guidelines to assist clinicians or consumers in
identifying persons who will be successful users of
integrated controllers.
Goals
1. To determine criteria necessary for successful use
of integrated controls by persons with multiple
technology needs and complex physical
conditions.
2. To identify service delivery components which
support the recommendation and provision of
integrated controls.
Methods Summary
A survey for interviewing successful users of
integrated controls was developed in conjunction
with the Office of Research at the University of
Pittsburgh. Survey topics included, but were not
limited to, user characteristics, environmental factors,
amount and type of training and back up and
maintenance of systems. Respondents were located
through clinicians that worked in North American
institutions that were multidisciplinary and known
for their work in assistive technology. Thirty
clinicians were contacted and assisted in the
recruitment process. The survey was administered
over the telephone and results tabulated and
analyzed. A Likert type ranking system was used to
analyze survey results.
Outcomes Summary
Twenty-four people with severe physical
disabilities, who used integrated controls,
participated in the telephone survey. The survey
focused on their satisfaction with areas related to use
of an integrated control device. Respondents were
generally satisfied with their integrated control
devices. A moderate correlation coefficient was found
between gadget appeal and satisfaction with devices.
The sample was self-selected and voluntary.
Three areas were identified as leading to
satisfaction with integrated controls. One, the
introduction of the integrated controller gave the
respondents a method of accessing devices that, prior
to receiving the controller, they were unable to
operate. Second, some form of training took place.
Either the trial or error or trial and error plus a manual
were used for training in cases where persons were
satisfied with their integrated controllers. This
information might help clinicians select a training
method. Finally, persons who liked gadgets were
more likely to be satisfied with integrated controllers.
A second survey was completed with clinicians that
recommend integrated controls. Issues affecting their
recommendation of integrated controls included the
availability of technical support and the comfort of
the clinician with the technology.
Due to the small sample size and the fact that the
group was self-selected, the results must be
interpreted carefully and should not be generalized
to the population of persons using integrated control
devices. Further studies need to be conducted to
support or refute these findings. One group that may
be surveyed is the population that has abandoned
integrated control device to examine why the devices
were abandoned. Another area that should be
investigated is how these results differ when
surveying children. The device procurement,
receiving devices all at once or over time, the learning
curve, and type of training may be quite different
depending on the age and experiences of the
individual user. This survey demonstrated that
persons using integrated control devices were, in
general, satisfied with them.
16 RERC ON WHEELCHAIR TECHNOLOGY

Recommended Future Research
Authors propose that a survey should be
conducted on the population that has abandoned
integrated controls. Another area that should be
investigated is how these results differ when
surveying children rather than adults. Finally,
training methods utilized with complex high
technology systems need to be investigated.
Publications
Angelo, J., Trefler, E. (1996). Surveying satisfaction of
integrated controls users. Proceeding of the RESNA
‘96 Annual Conference, Salt Lake City, UT, June 1996:
212-214.
Trefler, E and Angelo, J. Surveying Users of
Integrated Controls - A Pilot Study. Proceedings,
ARATA. Adelaide, Australia, October 1995: 17-19.
Angelo J and Trefler E, (1998), Satisfaction of Persons
Using Integrated Controls, Assistive Technology, 10.2.
77-83.
FINAL REPORT: 1993-1998
17

TASK: PM-6 NEW CONCEPTS IN
POWERED INDOOR MOBILITY
Investigators: Douglas Hobson, Linda van Roosmalen
Collaborators: Jules Legal, Steve Stadelmeier
Rationale
Very few powered wheelchairs have been
optimized for activities conducted in tight indoor
environments. Reaching up and down, transferring
and maneuvering in confined spaces are examples
of these activities. Many older persons with
disabilities have need for such mobility products, but
will often reject the notion if it makes a statement
about their disability. Aesthetics is an important
component to acceptance and, therefore, it was given
high priority in this task.
Goals
1. To provide increased indoor powered mobility
options for consumers of all ages and disabilities
with emphasis on environments of older persons.
2. Refine commercially promising designs and
facilitate transfer to the marketplace.
Methods Summary
The PM2 Advanced Mechanisms task addressed
the wheelchair steering problem by using a
mathematically designed cam and linkage steering
arrangement. This task addressed the need for
increased indoor maneuverability by using two
software-controlled servo-steering motors to control
the position of the two front drive motors. A
prototype, termed the PM6-MKI was developed
which also featured a novel tiller-type joystick control.
The software algorithm compensates for the
difference in turning radius of the two front driving
wheels and thereby minimizes any wheel scrubbing
effect. (Figure 11). The front wheel drive motors used
in the prototype were Fracmo, Model: M453-W30,
previously developed by Legal and Hobson. First
stage comparative maneuverability testing was done
using existing powered wheelchairs typically used
indoors as the benchmark.
A second design, the MKII, which grew out of
our relationship with the students and faculty in the
Design Department at Carnegie Mellon University,
is shown in Figure 12. The Quality Function
Deployment (QFD) [Jacques et al., 1994; Logan &
Radcliffe, 1997] tool was used to establish the design
criteria. This prototype addresses the need for
improved esthetics and self-adjustability of seat
height and angulation. Re-cycled motor drives
combined with a standard controller were used to
power the prototype. Two linear actuators control the
height and inclination of the seat.
The task plan called for the combining of the best
features of each prototype into a final demonstration
product. The full implementation of this plan was
dependent on the availability of a new motor drive
system, which was the focus of MK I prototype and
task PM-1d. In spite of several efforts at working
directly with motor drive manufacturers, we were
unsuccessful in convincing a company to invest
resources in a newly configured motor drive system.
Illustrations of the MK I and MK II designs follow.
Figure 11 – PM6-MK I Evaluation Prototype
TILLER-TYPE CONTROL
STEERING
MOTOR
POWEREDSTEERING
18 RERC ON WHEELCHAIR TECHNOLOGY

Concept illustration based on QFD criteria Working Prototype
Figure 12 - MK II Prototype
Figure 13 - Corridor
Figure 14 - Bathroom
FINAL REPORT: 1993-1998
19

TEST WHEELCHAIR DATA
Wheelchair Powered by Front wheel type Footprint
MK I Powered front wheels Steered powered wheels 80 x56 cm
Quickie P190 Powered rear wheels Swivel caster 107 x 61 cm
E&J Tempest Powered rear wheels Swivel caster 94 x 65 cm
Outcomes Summary
a) Laboratory Feasibility Testing of the PM-6 (MK
I) Prototype
The purpose of the feasibility test was to compare
the maneuverability of the MK I prototype to that of
production wheelchairs designed for similar usage.
Two production wheelchairs, Quickie P190 and the
E&J Tempest, were selected for the tests. The tests
consisted of running the three wheelchairs through
three typical environmental spaces setup as a
laboratory test course. Each space was laid out
according to the dimensions of the Uniform Federal
Accessibility Standards.
The course setup consisted of the following three
spaces as shown in figures 13-16 below. The
dimensions of the test spaces are as follows:
Corridor: w=91.7 cm; Bathroom: w x d=152.3 x
142 cm; Elevator: w x d= 171.2 x 129.3 cm
Walls for each space were fabricated from
replaceable 3/4” thick polystyrene foam sheets,
which showed damage marks each time they were
contacted by a wheelchair.
Figure 15 - Elevator
Test Method
The MK I, Quickie P190 and the Tempest
wheelchairs were randomly assigned to 4 test
subjects, all non-experienced wheelchair users. The
subjects were all given the same time to become
familiar with the standardized test course. They were
then asked to maneuver through the test course, twice
with each wheelchair.
Time was measured for each wheelchair to
maneuver through each space. The time started when
the front feet of the test wheelchair passed the space
Figure 16 - Overview of the complete course layout. The
lines indicate the required maneuvers.
threshold line. The time was stopped when the
wheelchair exited past the space threshold line. Also,
within each space the number of hits with the course
“wall” was recorded.
The first space, the corridor, was entered in a
forward direction. The subject had to first steer the
20 RERC ON WHEELCHAIR TECHNOLOGY

wheelchair into the right corridor and proceed until
they could touch a designated point on the wall with
their hands. They then backed down the corridor until
they could turn right and exit through the entrance
corridor.
The bathroom space had to be entered in a
forward direction. An object on the simulated vanity
was touched. The subject then backed out of the
bathroom.
The elevator space was approached in a forward
direction. The subject then turned 180 degrees and
touched the simulated control buttons for the elevator.
The subject then exited the elevator forward facing.
Results
The test results were analyzed in such a way that
the maximum speed of each wheelchair did not
influence the outcome of the test. The sample results
of the tests are shown in the following graphs. The
first two graphs are for a single subject; the last two
are the averages for all subjects.
The graphs indicate that in most cases the PM6 -
MK I wheelchair resulted in the shortest test time and
the least number of inadvertent walls impacts. Little
difference was seen in the time needed for the
washroom test. The reason for this may be that the
overall maneuvering requirements of the space were
not extensive. Whereas, in the corridor test, most
subjects took substantially longer to maneuver with
the Tempest and the Quickie wheelchairs than with
the MK I wheelchair. Finally, the elevator test was a
time consuming task for all three wheelchairs. In
terms of wall impacts, the graphs indicate that the
PM6-MKI wheelchair clearly performed better then
the other two test wheelchairs.
60
50
Average Test Time 1
PM-6: 4.48m2
Tempest: 6.11m2
Quickie P190: 6.53m2
Average time
(sec)
40
30
20
10
0
Corridor Elevator Washroom
Figure 17 - Average test time of subject #1 per space for the three test wheelchairs
FINAL REPORT: 1993-1998
21

9
8
7
Amount of Hits per W/C 1
PM-6: 4.48m2
Tempest: 6.11m2
Quickie P190: 6.53m2
Average
amount
of hits (n)
6
5
4
3
2
1
0
1 2 3
Figure 18 - Average number of wall impacts by subject #1 for each test wheelchair
14
Average Number of Hits
12
10
Number
of hits (n) 8
6
4
2
0
Corridor
Elevator
PM-6: 4.48m2 0.5 2.5
Tempest: 6.11m2 12.5 12
Quickie P190: 6.53m2 11.5 8.5
Figure 19 - Average number of wall impacts for all subjects for the three wheelchairs/spaces
22 RERC ON WHEELCHAIR TECHNOLOGY

45.0
Average Test Time
40.0
35.0
Time
(sec)
30.0
25.0
20.0
15.0
10.0
5.0
0.0
Corridor Elevator Washroom
PM-6: 4.48m2 21.0 15.0 10.2
Tempest: 6.11m2 37.4 19.2 15.3
Quickie P190: 6.53m2 40.1 20.7 9.4
Figure 20 - Average test time for all subjects for the three wheelchairs/spaces
Discussion
All wheelchairs used in the tests had different
‘footprints’, the MK I being the smallest. Therefore,
direct comparisons and any conclusions from the
results must be done with caution. For example,
reduction in the footprint size of the production
wheelchairs to that equal to the MK I wheelchair
would most likely improve their wall impact
performance. Also, the difference in maneuverability
times could be effected by the larger footprint size of
the production wheelchairs and not be totally due to
the enhanced maneuverability of the MK I prototype.
The Tempest and Quickie wheelchairs have front
swivel casters, which makes it impossible to
maneuver backwards from a forward maneuver
without first causing a lateral ‘shift’ of the front end
of the wheelchair. This was, in some cases, the reason
for higher number of wall impacts of the production
wheelchairs. Whereas, the MK I wheelchair, having
powered steering of the front wheels, does not exhibit
lateral shifting when reversing course.
Finally, because of the small size of the test
sample, no statistical analysis was attempted.
Therefore, it is only an observational conclusion that
can be drawn from this simplified feasibility test.
FINAL REPORT: 1993-1998
23
As mentioned, the MK I design also features a
uniquely designed tiller-type joystick. The idea is that
most elderly people will intuitively relate better to
tiller control (side to side movement to steer up and
down for reverse and forward, respectively). Also, the
direction of the tiller could be coupled electronically
to the direction of the steered wheels, so at start-up
there would be no directional surprises. Although this
joystick design worked well during the tests, no
comparative tests with the conventional joystick were
possible.
b) Development of the MK II Design
In brief, the purpose of the MK II design was to
explore the following criteria for an indoor wheelchair
that would provide:
• an alternative to the scooter for indoor/home use,
• an economic way to give elderly people mobility
in institutional settings,
• an alternative for the indoor/outdoor for home
to office use,
• an alternative for ADA accessibility into tight
workspaces, offices,

Figure 21 - Seat raises and tilts to aid in standing. Foot rests
drops to floor.
• a better way to vary the sitting height of a person
in a W/C, and
• a more esthetic and less stigmatizing way of
providing powered mobility.
Focus groups, user surveys and the Quality
Function Deployment (QFD) tools and the MK I
experience were used to explore questions and solicit
concepts leading to a list of weighted design criteria.
A sample questionnaire containing comments from
wheelchair users can be reviewed in Appendix A. The
summary results of the QFD analysis are also
contained in Appendix A. The MK II prototype shown
in figures 21-22 resulted from these intensive
planning efforts. The working prototype embodies
the following key features:
• a nontraditional frame and elevating/tilting seat
system,
• a ergonomically designed seat with swing up
armrests for ease of transfer,
• powered front wheels, castered rear wheels
allowing increased maneuverability in tight
indoor spaces. (Steered front wheels were
planned but suitable units were not possible to
obtain for the prototype construction),
• miniature integrated joystick control,
interchangeable between left and right armrests,
and
• a non wheelchair-like appearance intended to
minimize the stigma of disability.
The Mark II design was featured at the 1998
RESNA Conference exhibit. Interest was
demonstrated by clinicians, wheelchair users and two
prospective wheelchair manufacturers. Below are
several photos showing some of the features of the
MK II design.
Recommended Future Development
Figure 22 - Arm rests flip back to aid in transfer and work
place access .
Given that both demonstration outcomes were
basically positive, this development now requires
significant resources to integrate the best of the
demonstrated MK I & II features, complete with a
newly developed motor drive system. It will require
the formation of a partnership between the
developers, and, at least, a committed wheelchair
24 RERC ON WHEELCHAIR TECHNOLOGY

manufacturer and motor/drive developer-supplier
to transition the development towards commercial
availability. The investigators have made plans for
the formation of such a partnership and an SBIR
submission is under preparation to help finance the
venture. Assuming success with the SBIR submission,
the plan calls for the development of an integrated
MK III design. The MK III will then be subjected to
more rigorous laboratory and user testing as part of
its Phase I feasible evaluation.
Publications (in preparation)
References
Jacques GE, Ryan S, Naumann S, Milner M, Cleghorn WL
Application of Quality Function Deployment in
Rehabilitation Engineering, IEEE Transactions on
Rehabilitation Engineering, Vol. 2, No. 3, September 1994.
Logan GD, Radcliffe DF Potential for use of quality matrix
technique in rehabilitation engineering. IEEE Transactions
on Rehabilitation Engineering, Vol. 5, No. 1, March 1997.
Brown PG, QFD: Echoing the voice of the customer, AT&T
Technical Journal, March/April, 1991, pp. 18-32.
Hauser JR, Clausing D The house of quality, The Product
Development Challenge, Harvard Business Review Book,
eds. Kim B. Clark and Steven C. Wheelwright, pp. 299-
315, 1995.
FINAL REPORT: 1993-1998
25

TASK: PM-7 POWERED MOBILITY SIMULATOR
Investigators: Douglas Hobson, Nigel Shapcott, Mark Schmeler
Collaborators: Robert Lang, Jules Legal
Rationale
Evaluation for powered mobility can be a difficult
and time consuming process for both service
providers and wheelchair users. The decision to
recommend or purchase a powered wheelchair must
be done carefully and with maximum consumer
involvement as the costs are often high and the
mistakes are difficult to rectify after the fact. For
individuals with severe disabilities, the selection
process can often involve trials with different types
of input controls in an effort to determine if powered
mobility is even a viable option. For others who have
been long time manual wheelchair users, manual
propulsion may become increasingly more difficult
as a result of progressive disability or older age. A
powered wheelchair simulator is a multi-purpose tool
that allows consumers and clinicians to experiment
with powered mobility options at a relatively low cost
in an effort to make informed decisions prior to the
purchasing process. It allows a person in their manual
wheelchair, in their typical seated posture, to
experience the sensation of being in a powered
wheelchair. The concept is based on having a
powered platform or simulator onto which a person
can wheel their manual wheelchair. Controls can be
readily selected and positioned to meet the individual
needs of the user. Assuming the trial is positive, the
clinician, working closely with the user and assistive
technology supplier, can then more confidently
formulate the specifications for the definitive
powered wheelchair. This approach can be a
significant improvement over the typical trial and
error approach, as well as reduce the chances of
prescription error and ultimate disappointment by
the user. Research work conducted by Mark Schmeler
and Nigel Shapcott, while at the University of Buffalo,
indicates that the sensation experienced by users
while on the simulator closely parallels the motor/
perceptual sensations experienced in an actual
powered wheelchair (Schmeler, ’95).
Methods Summary
A first generation prototype simulator was
constructed during the latter part of Year II.
Evaluation of the first generation prototype was
performed in the University of Pittsburgh Medical
Center’s Center for Assistive Technology (CAT). A
local assistive technology supplier was invited to
participate in the prototype implementation and
evaluation. The results of this interaction were
positive, including suggestions for MK-II design
improvements. A mechanical designer (Jules Legal)
was added to the team. An unsuccessful STTR
proposal was prepared and submitted to NIH/
NCMRR in partnership with two local firms in Yr.
III. Year IV focused on continued refinement and
testing of the MK-II design with consumers in the
CAT. Based on the positive local experiences, a
second, revised STTR grant proposal was submitted.
It was not successful. The CAT also produced several
units for use by other clinical facilities.
Figure 23—Powered Mobility Simulator prototype based on the
Suny-Buffalo design.
26 RERC ON WHEELCHAIR TECHNOLOGY

Outcomes Summary
Transfer of this development to the marketplace
was dependent on a commercial partnership and the
receipt of technology transfer support from external
sources. As indicated above two attempts at securing
the necessary federal support were unsuccessful.
Several reviewers questioned the viability of such a
product given its limited application and therefore
numbers that can be potentially sold. This may
possibly be the case. However, we were gratified that
Mark Bresler, [Bresler, ML, 1990], one of the early
proponents of the wheelchair simulator concept,
exhibited a new prototype at the 1998 RESNA
conference. Hopefully he has captured the interest of
a commercial entity that will make this “orphan”
development available to those clinicians in most
urgent need.
Publications
Schmeler, M.R. Performance Validation of a Powered
Wheelchair Mobility Simulator, Proceedings of the
Eleventh International Seating Symposium, Pittsburgh,
PA, February 1995
References
Bresler, MI Turtle trainer: A way to evaluate power
mobility readiness. Proceedings of the Thirteen Annual
RESNA Conference, 1990
FINAL REPORT: 1993-1998
27

TASK: MM-1 STRUCTURAL IMPROVEMENTS TO
MANUAL WHEELCHAIRS
Investigators: Clifford Brubaker, David Brienza
Collaborators: Phil Ulerich and Catherine Palmer, Westinghouse Corp.
Rationale
The purpose of this project was to design and
develop a novel wheelchair with a unique
combination of features. This wheelchair design was
intended to address a market need for a wheelchair
capable of folding compactly for stowage (e.g.,
overhead compartments during commercial air
travel), accessing narrow passageways and other
areas requiring a compact profile and footprint, and
providing a high degree of maneuverability. Our
intent was to design an “Enhanced Access
Wheelchair” to achieve these capabilities without
sacrificing the performance characteristics essential
for everyday use (Figure 24). We also attempted to
determine the feasibility of incorporating fiber
reinforced material technology.
Figure 24 - Enhanced Access Wheelchair.
Goals
The goals of this project, as originally proposed,
were to design, fabricate and evaluate an aesthetically
pleasing, general-purpose wheelchair that could be
easily stowed, manipulated and maneuvered through
narrow corridors. The conceptual design was
proposed to meet this objective by providing several
important features:
• Compact folding frame;
• Light weight (using composite materials);
• Three position (anti-tip, rear support and folded)
auxiliary wheels; and
• Attractively shaped solid side frame members
that allow for subtle incorporation of mechanisms
like brakes, releases and structural members.
Three prototype wheelchairs were designed,
fabricated and tested in the course of this project. The
final design incorporated side frame members made
from inexpensive, molded thermoset materials. Other
frame components were eventually machined
individually from aluminum stock due to difficulties
with machined composite parts. It was (and is) our
expectation that these parts could be manufactured
more efficiently in production models. The
dimensions of the folded frame are 5.5 inches wide
by 21 inches deep by 12 inches tall with the footrest
mounts and main wheels removed and not including
the back rest. The wheelchair is shown folded in
Figures 25 and 26. Auxiliary wheels are included to
allow passage through openings as narrow as 18
inches (overall width is defined explicitly by the seat
width) when the main wheels are removed (Figure
27). The development effort has focused on the
incorporation of these novel features and
manufacturing processes. Weight reduction will be
an objective for subsequent design iteration.
An important secondary goal of this project was
to demonstrate alternative materials and
manufacturing techniques for the production of
wheelchairs. Our experience with this option is
summarized in the following section of this report.
28 RERC ON WHEELCHAIR TECHNOLOGY

Figure 25. - Side view of folded wheelchair.
Methods
A CAD design for the prototype wheelchair was
executed using CADKEY. This design was exported
to a more sophisticated CAD system at Westinghouse
Corp. Science and Technology Center where the
design was further refined. A structural analysis
using ANSYS, a finite element analysis program, was
conducted to determine the necessary material
strengths for the different parts. Stress analyses were
performed on individual components and for an
articulated model of the prospective prototype. Upon
completion of the design and computer simulation
phases, the project proceeded to the development of
the physical prototype. Thermoset materials were
considered as a low-cost production option for
wheelchair structures.
Inexpensive, molded thermoset materials offer
several advantages for use as low cost wheelchair
structures. Two major disadvantages are
manufacturers’ lack of experience with thermoset
molding and the high initial cost of molds. Both of
these problems were considered in this project.
The structural elements of the wheelchair were
designed as compression molded, glass filled
polyester components. One reason for this selection
is the very low cost of this material. It is used
commonly in industry for electrically insulated
structural parts. Since it is an engineered plastic, an
entire range of material strengths, weights and costs
are available. This allows for trade-off between
weight and cost in the design and manufacture of
wheelchairs. The basic design and geometry of this
wheelchair was defined substantially by the novel
folding mechanism of the chair and by common
structural requirements for wheelchairs.
A few iterations of weight reduction analysis were
done on the parts to save some material. Considerably
more refinement is possible. The chair was modeled
as plate elements and loaded with a 200 kg dummy
at 3 g’s. Consideration was given to both the
maximum von Mises stress and the maximum
deflection. Acceptable deflection was based only on
assumed aesthetic perceptions for the prototype
development. The stress limit was determined from
isotropic treatment of the maximum allowable tensile
stress.
Figure 26 - Folded (front).
The high cost of mold fabrication precluded mold
development for parts other than the side frame. Parts
were initially machined from sheet stock. This
decision was made with the knowledge that
machined composite parts typically have structural
strengths on the order of 40% less than comparable
FINAL REPORT: 1993-1998
29

molded parts. This loss of strength is well
documented and results from surface cracks and
defects left from milling the smooth, fiber free
surfaces. The use of machined composite parts proved
not to be a viable solution in subsequent testing. The
parts (other than the side panels) were subsequently
machined from aluminum sheet and bar stock.
Figure 27 - Side view with main wheels removed.
The molding technology chosen for this project
is based on spray metal tooling. This technique for
mold making takes about a month and costs less than
$8,000. This process is rather new and has seldom
been used on compression molded parts of this size.
Only 20 to 150 parts would be expected from this tool.
By contrast, standard mold construction (using steel)
for comparable sized parts would require 4 to 6
months to complete at a cost on the order of $70,000.
These steel molds could be used to produce 500,000
to 5,000,000 parts. Standard aluminum molds are less
expensive ($45,000), quicker to machine
(approximately 3 months), and would be suitable for
producing 5,000 to 25,000 parts. The project provided
an opportunity to consider the efficacy of
compression molded parts at modest cost.
The mold was fabricated over the course of 8
weeks and was received at Penn Compression near
Pittsburgh, PA. The mold was made from a wood
model of the final part, which was placed in an inert
bed up to the mold parting line. An electric spray head
was used to sputter-coat thin layers of a zincaluminum
alloy onto the pattern. Zinc-aluminum
wire is fed into the spray head and electrically melted.
Repeated layers of sprayed metal were applied until
a shell was created from 1/8 to 1/4 inch thick. This
shell was backed with an aluminum-filled epoxy to
provide strength and stiffness and placed into a cold
rolled steel frame about 1/2 inch thick. This process
was repeated to form the other half of the mold.
Unfortunately, the mold was incorrectly developed
as a conventional injection mold, rather than as a
compression mold. For injection molding the mold
is parted at the midline with two symmetrical (in this
instance) halves that are held in opposition while
material is injected. In contrast, a compression mold
has a “force” component and a “cavity” component
as the two “halves.” Without a force and cavity, it
was difficult to assure that sufficient material would
be incorporated into the mold to fill the part. After
six attempts the proper charge of bulk molded
material to fill the part was determined. After the
third piece was molded, the ejector system failed and
the molder was forced to pry subsequent pieces out
of the mold using hand tools. This was difficult, as
the mold must be stabilized at 350 degrees before the
molding process can begin. The failure required a
modification of the mold. It became necessary to
machine away extra material. This ultimately
weakened the parts.
Figure 28 - Narrow access.
30 RERC ON WHEELCHAIR TECHNOLOGY

The molded side-frame had four “through
holes,”including a 1" diameter main axle hole and
three 1/4 inch diameter holes to stop the auxiliary
wheel in its various positions. Of the parts produced,
five did not fill completely and several others were
broken while being ejected from the tool. In the end,
six acceptable parts were made, allowing for the
assembly of three prototypes.
Prototype assembly
Fabrication of an initial prototype resulted in the
discovery of weaknesses in the original design. As a
result of the initial fabrication phase, a substantial
number of the components were redesigned with the
goal of increasing the structural integrity of the
wheelchair frame. The modified designs were used
to fabricate two additional prototypes, which were
evaluated using applicable ISO standard test
procedures. The modified version is shown in Figure
29 and 30.
Figure 29 - Assembled Prototype.
ISO Test Evaluation of the prototype
The first of the modified prototypes was tested
according to ISO 7176-8 (Wheelchairs - Part 8:
Requirements and test methods for static, impact and
fatigue strength). The chair passed all static and
impact strength tests with the exception of armrest
upward weight bearing. The armrest upward force
test is not applicable to our design since the armrests
were designed to release with upward force. The chair
successfully completed 200,000 cycles on the twodrum
fatigue strength test without failure, but failed
after 2055 cycles of the curb drop test. This failure
was a fracture of the side frame where the footrest
and front caster wheels are attached. Prior to the
testing, we observed cracks in the frame resulting
from a poor fit between the molded side frame and
the footrest/caster wheel mount. It will be necessary
to address this area of structural weakness in the
design of future prototypes using molded
components.
Consumer Evaluation of the Prototype
Initial evaluation was provided by an
experienced wheelchair user and resulted in several
comments and suggestions:
• The concept of the design is attractive. The ability
to remove the rear wheels and use 8 inch auxiliary
wheels to roll down an airplane aisle or in a small
rest room would be useful. (Figure 28)
• The ability of the chair to fold and break-down
into small components makes it attractive for
storing in overhead compartments of aircraft or
in compact automobiles.
• The folding mechanism is awkward and
cumbersome. The wheelchair can become difficult
to fold if the central pin loses alignment with the
cross-braces. The dovetail joints bind and are
prone to jamming from dust and dirt.
• The wheelchair is much too heavy. The materials
need to be changed and the overall design
lightened.
• The wheelchair is too tall and the leg rests are
positioned too far forward.
• The auxiliary wheels do not perform adequately
as anti-tip devices and are cumbersome to use.
• The wheelchair and center of gravity are not
adequately adjustable.
• The backrest folding mechanism is bulky and
does not provide adequate lateral stiffness.
FINAL REPORT: 1993-1998
31

• The chair has multiple pinch points that need to
be eliminated
• The wheelchair provides a proof-of-concept and
would require additional refinement prior to
being acceptable to consumers.
wheelchair that allows access to narrow corridors and
is rigid and durable enough for everyday use is now
several years old, there is still considerable need for
such a product by many wheelchair users. As a result,
we feel that the market potential for a wheelchair with
these features is still significant. This initial funding
provided the basis to take the most critical step in the
research and development process: from conceptual
design to full-scale working prototype. There are still
several important engineering problems to solve
before the eventual development of a commercial
product; however, we have successfully
demonstrated the feasibility of producing the
wheelchair for enhanced access. Although it was not
our primary objective, we have also shown the
possibility of using parts manufactured with
inexpensive techniques and materials.
External Evaluation
Figure 30 - Front view of assembly
Several of these problems have already been
addressed. For example, the seat was redesigned to
eliminate the possibility of pinching while it is being
opened. The backrest support brackets were
redesigned since this initial evaluation was made.
Amelioration of all other shortcomings is being
considered. The design will require further iteration
to become viable for commercial development.
Outcomes Summary
Our initial impression of the prototype relative
to its performance is positive. The solid seat together
with the cross braces and side frame members form
a support structure that feels significantly more rigid
than typical “X” cross brace frame, folding
wheelchairs. Even with the large main wheels
removed for narrow access, the wheelchair was
sturdy and stable. In informal trials in our laboratory,
varying users have found the chair’s performance to
exceed their expectations for a folding frame
wheelchair. A formal beta test program will be
developed as the next stage of development.
Although the concept of a compactly folding
A more thorough demonstration and evaluation
was conducted by the RERC on Technology Transfer
at SUNY Buffalo. The Enhanced Access Wheelchair
was evaluated by three focus groups of 30 consumers
who had used a manual wheelchair for a minimum
of five years. Some general results from comparisons
with existing commercial products were particularly
encouraging:
1. 55% of the consumer participants preferred the
prototype to existing products.
2. Consumers were willing to pay up to $200 more
for the features incorporated in the Enhanced
Access Prototype.
3. Consumers increased the additional amount they
would pay for the prototype features to $370
(mean) after viewing the features of a competing,
production model wheelchair.
4. Among features valued by the consumers were
the folding mechanism, the folded size, and the
3-position deployment of the auxiliary wheels, the
“solid” seat, and the aesthetics of the side-frame.
Disadvantages identified included the
imprecision and “awkwardness” of the
mechanisms, the overall weight, and the lack of
tie-down points. Suggestions were generally on
ways to improve the mechanisms and decrease
32 RERC ON WHEELCHAIR TECHNOLOGY

the weight. One of the strongest preferences for
the prototype over production folding chairs was
the folding mechanism. It was perceived to be
more stable and to allowed more compact folding.
Recommendations for Future Development
The project has progressed to the point of
successful demonstration of several valuable features
of a manual wheelchair. We believe that the
evaluation information is sufficiently positive to
warrant further development. Initial plans for a
second generation prototype have been completed.
We believe that it will be necessary to produce a metal
frame model to gain the interest of current
manufacturers. If we can obtain additional funding
for this project we shall proceed with development
of an all metal prototype in which we shall refine the
mechanisms and reduce the weight of the wheelchair
as suggested by the consumer panels.
Publications and Technical Reports
Brienza, DM, CE Brubaker (1996) Design and Development
of a Wheelchair for Enhanced Access, RESNA Proceedings,
16:250-252.
Brubaker CE, Brienza DM, Ulerich P “Design and
Development of a Wheelchair for Enhanced Access,” Final
Progress Report, SCRF Grant #1218, Paralyzed Veterans
of America, November 10, 1995.
Ulerich P, Palmer, K, Stampahar,M, Brubaker, CE “Design
and Development of a Wheelchair for Enhanced Access,”
First Annual Report to the Paralyzed Veterans of America
Spinal Cord Research Foundation, Grant #1218-01, March
16, 1994.
FINAL REPORT: 1993-1998
33

TASK: WP-1 CONSUMER RESPONSIVE MOBILITY
PRESCRIPTION PROCESS
Investigators: Elaine Trefler, Heather Rushmore
Rationale
Consumers who use manual wheelchairs have
expressed the view that their first wheelchair did
not meet their personal needs. The purpose of this
study is to develop a consumer responsive wheelchair
prescription process for first time wheelchair
users who are functioning as paraplegics.
Over the past several years, consumer-responsive
services have become the highly studied
means of providing assistive technology and
rehabilitation services. In the past, consumers were
not given ample choices nor were they often asked
to contribute to the decision making process.
Often, all decisions were, and at times still are
today, made by the medical/therapy team. Due to
the lack of involvement by the consumer, he/she is
often dissatisfied with the assistive technology
received.
Goals
1. To determine the components of a service
delivery process that support consumer satisfaction
both with the process and the product
during the provision of their first wheelchair.
2. Propose enhancements to the service delivery
model based on the findings.
Methods Summary
The following steps were taken to address the
above goals:
1. Develop an interview instrument to determine
consumer satisfaction with the prescription
process for a first time wheelchair user, administer
it to at least one individual to obtain input
into the areas that need refinement and gather
feedback to develop discussion areas and
questions for a focus group.
2. Form a focus group to gather ideas on ways to
improve the wheelchair prescription process.
Use input from the focus group to further refine
the interview instrument.
3. Identify and interview 30 consumers (15 who
received services from a multidisciplinary
clinical setting and 15 from a nonmultidisciplinary
setting) with the interview
instrument developed to determine consumer
satisfaction with service delivery and wheelchair
technology.
4. Review current practice based on information
and data collected from the focus group and
interviews.
5. Develop and propose enhancement to the
service delivery model based on the data
collected in steps 1-4.
Outcomes Summary
A focus group of five expert wheelchair users
was assembled to generate ideas on improving
current prescription processes. The group
brainstormed 31 ideas and ranked the top six ideas,
which were:
1. focus on the person;
2. consumer testing of different wheelchairs;
3. education on different wheelchairs for different
activities;
4. evaluation of the consumers home;
5. wheelchair user as a team member; and
6. peer counselor/mentor as part of the team.
Publications were prepared for both consumer
and professional publications, which summarized
the results of the focus group. The main themes
were that consumers wanted to be involved as full
partners in the decision making, to be able to try
different options in their own environment and
access to advice from other wheelchair users.
34 RERC ON WHEELCHAIR TECHNOLOGY

Recommended Future Research
Based on the above experience we recommend
the following areas for further investigation:
1. Investigate effectiveness of education and
training methods for consumers. Document
consumers’ perceptions of training practices
and determine compatibility with active practice.
2. Compare consumer’s first prescription process
to their most recent to determine features and
satisfaction level.
3. Investigate the possible differences between
satisfaction and adjustment levels of individuals
with acquired and congenital disabilities
and how this might relate to components of the
service delivery process.
Publications
Trefler, E and Rushmore, H. A consumer responsive
mobility prescription process: The summary of a focus
group. Team Rehab Report, June 1997, 41.43.
Trefler, E, Fitzgerald, S, and Rushmore, H. Manual
Wheelchair Prescription Process: Consumer Satisfaction
with Multidisciplinary and Non Multidisciplinary
Approaches, In revision.
FINAL REPORT: 1993-1998
35

TASK: WP-2 WHEELCHAIR PRESCRIPTION SOFTWARE
PROJECT (WPSP)
Investigator: Nigel Shapcott
Rationale
Current wheelchair users and prescribers (OT, PT
and RTS students are the target population) have a
large and increasing selection of wheelchairs to
choose from, each having a variety of accessories that
customize the wheelchair to individual need. Thus,
the goal is to provide users the opportunity to
participate in the selection of the wheelchair that is
closest to being ideal for their needs.
Information overload caused by the significant
number of companies making wheelchairs, which
come in a variety of models with many configurable
options for each, leads to a large quantity of
information that has to be searched in order to make
appropriate selections. Information continually
changes as new models, options and companies enter
the market. Added to this is the fact that the
information between different manufacturers may be
difficult to compare because the wheelchair standards
testing information is not readily available.
Incorrect prescription or purchase of wheelchairs,
particularly among first time inexperienced
wheelchair users, is common among individuals with
spinal cord injury and other diagnoses where needs
change over time. There is a lack of training
opportunities that teach and inform prescribers on
the strategies of wheelchair prescription, taking
account of physical needs, functional environment,
funding and other issues, and relating these to the
priorities of a particular individual.
This collaborative project, to develop wheelchair
prescription software, has been funded mainly
through the Department of Veterans Affairs,
Rehabilitation Research and Development Service
(VA RR&D) as a component of the Computer Aided
Wheelchair Prescription System (CAWPS).
Goals
1. Develop a computer program that provides an
effective, easy to use wheelchair prescription
teaching aid.
2. Provide easy access to expert prescription
methodologies.
3. Commercialize the software in order to provide
a mechanism for widespread availability at
reasonable cost.
Methods Summary
An interactive computer based wheelchair
prescription system, using expert system
methodologies, has been developed. As part of this
development process, internal evaluation and
interactive evaluations were carried out using known
case studies.
Outcomes Summary
1) The software structure was stabilized January
1997. Educational features include:
• Quicktime videos to show different wheelchair
types and activities to educate and raise
expectations about what may be reasonable
achievements in education, work, leisure and
ADL activities.
• Graphics to explain dimensional information.
• Incorporation of a publication on wheelchair
selection as resource material (text and graphics).
(Axelson et al, 1994)
• Each question has an accompanying explanation
which can be accessed by a simple mouse click
(“Why Button”).
• Each feature of the final generic wheelchair can
be examined (simply by a ‘click’) to determine
which questions (and accompanying answers)
were factors in the selection of that feature.
36 RERC ON WHEELCHAIR TECHNOLOGY

2) A demonstration version is available at:
ftp.pitt.edu/users/s/g/sgarand.
3) Logic developed has been largely completed
and is currently in the testing and editing phase.
4) Formal testing was not carried out in order to
secure funds and protect confidentiality pending
completion of negotiations with a potential
commercial partner (see below). The input from
informal testing has been very positive for this
educational version.
5) The project has been successful in attracting
commercial interest. An agreement, through the VA
RR&D Technology Transfer Section with a major
health care company who expressed interest in
commercializing CAWPS, failed. The company had
intended to further develop CAWPS and make it
widely available through Intranet and Internet links
as well as in a stand alone format. Task WP-2, WPSP
was planned to be released as a low cost (possibly
free) version of the main CAWPS program as part of
the commercialization plans. In December 1998,
negotiations ceased.
6) Plans are now under way to obtain funding
for further testing.
Individuals interested in obtaining a
demonstration version of CAWS should contact Nigel
Shapcott preferably by e-mail at Shapcott@pitt.edu
or through the RERC at 412-647-1273.
Reference
Axelson P, Minkel J, Chesney D. Guide to wheelchair
selection: How to use the ANSI/RESNA wheelchair
standards to buy a wheelchair, PVA 1994
Recommended Future Development
1. Investigate the use of CAWPS as an
educational tool.
2. Investigate the use of CAWPS as an clinical
tool.
Publications
Shapcott, N and Garand, S. Computer-Aided
Wheelchair Prescription System, paper submitted to
Canadian Seating Symposium, Toronto, Canada, Sept
1996.
Shapcott, N and Albright, S. Computer-Aided
Wheelchair Prescription System, paper submitted to
Pittsburgh International Seating Symposium,
Pittsburgh, PA February 1997.
FINAL REPORT: 1993-1998
37

TASK: STD-1 PARTICIPATION IN THE DEVELOPMENT OF
WHEELCHAIR STANDARDS
Investigator: Rory A. Cooper
Rationale
Development and application of performance
standards is perhaps the most productive activity in
terms of affecting the improvement to the quality of
wheelchair products for the largest number of users.
However, standards development requires research
and testing in order to validate the test procedures
prior to their acceptance in national and international
standards. Standardized disclosure of test and
measurement data in presale brochures is a means
by which consumers can accurately compare
products prior to purchase commitment.
Goals
1. To participate in the development and revision
of wheelchair standards to ensure product quality
for consumers.
2. To participate in the development and revision
of wheelchair standards to provide sufficient
information for product comparison.
Methods Summary
Three basic methods were employed. The first
methods consisted of active participation in the
standards meetings at both the ANSI/RESNA and
ISO levels. This included chairing several of the
working groups, and for two years chairing the
RESNA Technical Guidelines Committee. The second
method was to provide supporting research and
development for the creation and revision of
standards. Without supporting data or devices,
reasonable standards can not be developed. The third
method employed applying the standards to
commercial products to provide comparison data.
This information was published to assist clinicians,
consumers, payers, and manufacturers.
Outcomes Summary
The key outcomes from this task can be
summarized as follows:
• coordinated the development of a complete
electric powered wheelchair/scooter
electromagnetic compatibility standard which is
in the voting process as of 12/98,
• contributed to the development of an electronic
integration interface standard (ISO CD7176/17)
being developed through TIDE, a program of the
European Economic Community,
• conducted a study to compare the results of
common hospital type wheelchairs with active
duty ultralight wheelchairs,
• conducted a study to analyze the performance of
selected lightweight wheelchairs.
• standards which consumers, practitioners,
manufacturers and purchasers can rely upon
more complete information by which to compare
products,
• quality of wheelchairs will be improved.
Recommended Future Developments
Work on the development of standards must
continue in order to ensure improvement in
wheelchairs. Moreover, product comparisons are
required to provide consumers, clinicians, and
manufacturers information about the safety, quality,
and value of wheelchairs. There are a substantial
number of wheelchair standards in development and
in revision. The application of wheelchair standards
continues to produce higher quality wheelchairs.
Publications
Cooper RA, Boninger ML, Rentschler A, Evaluation of
Selected Ultralight Manual Wheelchairs Using ANSI/
RESNA Standards, Archives of Physical Medicine and
Rehabilitation, Vol. 80, 1999.
38 RERC ON WHEELCHAIR TECHNOLOGY

Cooper RA, O’Connor TJ, Gonzalez JP, Boninger ML, and
Rentschler A, Augmentation of the 100 kg ISO Wheelchair
Test Dummy to Accommodate Higher Mass, Journal of
Rehabilitation Research and Development, Vol. 36, No. 1, 1999.
Cooper RA, Gonzalez J, Lawrence B, Rentschler A,
Boninger ML, and VanSickle DP, Performance of Selected
Lightweight Wheelchairs on ANSI/RESNA Tests, Archives
of Physical Medicine and Rehabilitation, Vol. 78, No. 10, pp.
1138-1144, 1997.
Cooper RA, A Perspective on the Ultralight Wheelchair
Revolution, Technology and Disability, Vol. 5, pp. 383-392,
1996.
Cooper RA, Robertson RN, Lawrence B, Heil T, Albright
SJ, VanSickle DP and Gonzalez J, Life-Cycle Analysis of
Depot versus Rehabilitation Manual Wheelchairs, Journal
of Rehabilitation Research and Development, Vol. 33, No. 1,
pp. 45-55, 1996.
Cooper RA, Harmonization of Assistive Technology
Standards, Proceedings 20th Annual IEEE/EMBS
International Conference, Hong Kong, CD-ROM, 1998.
Gonzalez J, Cooper RA, Rentschler A and Lawrence B,
Frame Failures of Welded Tube Manual Wheelchairs,
Proceedings 20th Annual RESNA Conference, Pittsburgh,
Pennsylvania, pp. 184-186, 1997
Lawrence B, Cooper RA, VanSickle DP and Gonzalez J,
An Improved Method for Measuring Power Wheelchair
Velocity and Acceleration Using a Trailing Wheel,
Proceedings 20th Annual RESNA Conference, Pittsburgh,
Pennsylvania, pp. 251-253, 1997
Cooper RA, Gonzalez J, Robertson RN, and Boninger MD,
New Developments in Wheelchair Standards, Proceedings
18th Annual IEEE/EMBS International Conference,
Amsterdam, Netherlands, CD-ROM, 1996.
Cooper RA, Robertson RN, Boninger ML, A Biomechanical
Model of Stand-Up Wheelchairs, Proceedings 17th Annual
IEEE/EMBS International Conference, Montreal, Canada,
CD-ROM, 1995.
Cooper RA and McGee H, Wheelchair Related Accidents
and Malfunctions, Proceedings 18th Annual RESNA
Conference, Vancouver, BC, pp. 334-336, 1995
Cooper RA, McGee H, Apreleva M, Albirght SJ, VanSickle
DP, Wong E and Boninger ML, Static Stability Testing of
Stand-Up Wheelchairs, Proceedings 18th Annual RESNA
Conference, Vancouver, BC, pp. 349-351, 1995.
FINAL REPORT: 1993-1998
39

II. IMPROVED WHEELCHAIR SEATING
♦S-1 CUSHION DESIGN FOR ULCER PREVENTION
♦S-2 ADVANCED MATERIALS AND MECHANISMS
♦S-3 IMPROVED USER INPUT DEVICES AND CONTROL CONCEPTS
♦S-4 INTEGRATION OF IMPROVED MOBILITY COMPONENTS
♦S-5 THE USE OF INTEGRATED CONTROLS BY PERSONS WITH PHYSICAL DISABILITIES
40 RERC ON WHEELCHAIR TECHNOLOGY

TASK: S-1 CUSHION DESIGN FOR ULCER PREVENTION
Investigators: David M. Brienza, Patricia Karg, Jue Wang, Chen-Tse Lin
Collaborators: Ying-Wei Yuan, Qiang Xue
Rationale
The prevention of pressure ulcers through the use
of custom contoured foam seat cushions (CCFSCs) is
one aspect of seating that can benefit the user through
investment in research. The efficacy of using CCFSCs
has been shown in clinical trials [Sprigle, et al 1990]
and is being established on a larger basis now that
CCFSCs are commercially available. Computer-aided
design and manufacture (CAD/CAM) technology
related to CCFSCs is limited to anatomical
measurement, ad-hoc data processing and shape
editing techniques, and the automated manufacturing
of cushions. The expansion of this technology to
systematic data processing techniques requires that
the existing gap in scientific knowledge concerning
the relationship between support surface shape and
interface pressure distribution be filled. The research
proposed in this task will work to fill this void in
knowledge. The flow chart of Figure 31(a) depicts the
current design process. The weaknesses of this
procedure is the dependence of the outcome on the
clinician’s knowledge and experience, and the trial
and error iteration involving repeated cushion
manufacturing, both of which add cost to the end
product. The improved prescription process is
illustrated in Figure 31(b). Generic modification
formulas, dependent on parameters like functional
ability, tissue tone, age, body weight, and gender, will
be used to eliminate the need for extraordinary skill
and experience on the part of the therapist and the
trial and error process. The proposed work focuses
on the needs of populations with specific
requirements for specialized and/or custom seating
for pressure relief as a prophylaxis for pressure ulcers.
(a) Current custom seating design process:
Shape
Measurement
Ad-hoc shape
modification and
design process
Cushion
Fabrication
(b) Future custom seating design process:
Iterative
Process
Fail
Evaluation
Pass
Customer
Satisfaction
Clinical
Measurement
Systematic shape modification
and design process
Cushion
Fabrication
Customer
Satisfaction
Physical charateristics of user
Other measurements
Optimization criteria
Implementing the design method will reduce the costs involved in providing seating
systems, produce higher quality results more consistently, and reduce the need for
extraordinary skill and experience.
Figure 31(a) - Current custom seating design process (b) Future custom seating design process.
FINAL REPORT: 1993-1998
41

Goals
1. To develop generic seat contour shape
modification techniques for persons with SCI and
elderly persons.
2. To add to the body of scientific knowledge related
to custom seat support surface design.
In Year III, the first year of this project, efforts
focused on the analysis and dissemination of
previously collected data [Brienza, et al 1996]. During
the progression of work in Year III, we identified the
need to further investigate the relationship between
external forces and soft tissue responses.
Understanding this relationship is critical to the
design of effective support surfaces. Thus, Year IV
work continued the analysis of the pressure and shape
data for elderly and spinal cord injury subjects. A
third manuscript was published [Brienza and Karg,
1998].
In order to develop the cushion design
techniques, the complex shape data had to be
reduced. A technique using singular value
decomposition was developed to normalize and
reduce the shape data. Further analysis of the
normalized data can then be accomplished using a
factor analysis such as principle component analysis.
Initial work has been done to characterize the shapes
and determine their relationship with interface
pressures on a flat surface.
Year V continued to define the relationship
between interface pressure and surface shape from
the existing shape libraries. This information will be
used to develop design and shape modification
techniques. A pilot study will be done to test and
refine the technique(s). The ultimate goal will be to
develop a method to design contoured cushions from
clinically accessible measures such as interface
pressures on a flat surface, anatomical dimensions
and other characteristics of the user.
Outcome Summary
The interface pressure distributions between flat
foam cushions and the buttocks of seated test subjects
were compared to custom contoured cushion surface
shapes generated with a seated buttock contour gage.
Our hypothesis was that pressure measurements
could be used to generate a contour equivalent to that
obtained with a force deflection contour gage. The
study was performed in a university medical center
using SCI (12) and elderly (30) test subjects. Interface
pressure was measured using a pressure mapping
pad. Contour shape was measured using an electronic
force deflection contour gage. Pressure and contour
information were reduced prior to analysis using
singular value decomposition. Polynomial
regressions were performed on the values in the first
singular vectors of the corresponding pressure and
contour decompositions. Relationships best described
by cubic polynomials were detected between pressure
and contour shape suggesting that interface pressure
predicts optimal contour shape. These results will
be published in IEEE Transactions on Rehabilitation
Engineering 1999.
Recommended Future Research
Our results should be viewed as preliminary and
further investigation is necessary to establish
appropriate transformation equations for particular
subject groups. In particular, we did not find the same
relationship between the flat pressure and contour
data for both subject groups. We have not determined
if the differences between subject groups reflect
intrinsic differences in soft tissue properties; or were
the result of the use of different thicknesses of foam
cushions during the pressure measurement
procedure (3" for the elderly and 4" for SCI); or were
caused by other factors. Furthermore, the results may
be dependent on the measurement techniques
employed, including the type of foam used and the
spring constantly used in the Electronic Shape Sensor
(ESS).
This study revealed relationships between the
interface pressure measured between the buttocks
and a flat foam seat cushion and the contour
measured using a force deflection contour gage. The
result indicates that custom contoured seat cushions
can be generated using interface pressure
measurements without the need for a contour gage.
Verification of the relationships is necessary to
validate the method.
42 RERC ON WHEELCHAIR TECHNOLOGY

Publications
Brienza DM, Chung K-C, Brubaker CE, Wang J and Karg
PE. A System for the Analysis of Seat Support Surfaces
Using Surface Shape Control and Simultaneous
Measurement of Applied Pressures. IEEE Transactions on
Rehabilitation Engineering 1996, (4)2: 103-13.
Brienza DM, Karg PE, Brubaker CE. Seat Cushion Design
for Elderly Wheelchair Users Based on Minimization of
Soft Tissue Deformation Using Stiffness and Pressure
Measurements. IEEE Transactions on Rehabilitation
Engineering 1996, (4)4: 320-7.
Brienza DM and Karg PE. Seat cushion optimization: A
comparison of interface pressure and tissue stiffness
characteristics for spinal cord injured and elderly patients.
Archives of Physical Med. and Rehabil. 1998;(79) April:388-
394.
Brienza, DM, Chen-Tse Lin, and Patricia E. Karg. A method
for custom contoured cushion design using interface
pressure measurements IEEE Transactions on Rehabilitation
Engineering 1999, (in press).
References
Sprigle SH, Chung K-C, Brubaker CE. Reduction of Seating
Pressure with Custom Contoured Cushions. J Rehabil Res
Dev 1990; 27(2): 135-40.
FINAL REPORT: 1993-1998
43

TASK: S-2 DISTORTION MEASUREMENT AND
BIOMECHANICAL ANALYSIS OF IN VIVO LOAD BEARING
SOFT TISSUES
Investigators: David M. Brienza, Patricia Karg, Jue Wang, Chen-Tse Lin
Collaborator: Ying-Wei Yuan, Qiang Xue
Rationale
Pressure ulcers continue to be a common
complication and costly clinical problem. Interface
pressure distributions between the buttocks and seat
support surfaces are used clinically to evaluate the
efficacy of seat cushions relative to the risk of pressure
ulcer development. Soft tissue deformation, resulting
in internal strain, is potentially a superior indicator
of pressure ulcer risk, however, limitations of current
clinical assessment technology render tissue
deformation measurements inaccessible in the clinic.
As an alternative, interface pressure, a parameter that
is clinically accessible, is used as an indicator for
potentially harmful internal stresses and strains. This
task was designed to provide additional support to a
research effort (Paralyzed Veterans of America, Spinal
Cord Research Foundation, PVA #1503) to develop
an ultrasound system that may be used to study in
vivo soft tissue response to external loading on the
weight-bearing human buttocks during seating, and,
therefore, a means to determine how external loading
contributes to the risk of pressure ulcer development.
Results from the work will also produce valuable
information concerning the efficacy of using external
pressure as an indicator for harmful internal strain
in soft tissues—muscle, skin and fat.
Goals
1. Design, develop and evaluate an ultrasonic
transducer that will be compatible with the
computer controlled seating system (CASS) and
useful in evaluating soft tissue response to
external loading in vivo
2. Design and evaluate a compound sensor
containing pressure, force, and ultrasonic
transducers
3. Develop and evaluate of a multi-channel
ultrasound system to allow for data collection
from and control of the ultrasonic transducers
4. Integrate ultrasound system and force
measurement system into the CASS
5. Develop and evaluate software tools necessary
for control of new system
6. Perform pilot and clinical evaluations to test
system performance and efficacy
Outcome Summary
A unique ultrasound-seating system for soft tissue
characterization has been developed at the University
of Pittsburgh based on the CASS system developed
by Brienza et al. [Brienza et al., 1996]. Ultrasonic
detection has been combined with the closed-loop,
dynamically controlled shape and pressure sensing
system. This allows quantification of the complex
relationships between shape, tissue deformation and
interface pressure under controlled loading
conditions. This system contains an 11 by 12 array of
sensors for which the height can be computer
adjusted to vary loading conditions and surface shape
in 3-dimensions. Ultrasonic and force transducers
have been integrated into 9 of the support element
heads to form a 3 by 3 array so that we can also
investigate soft tissue deformation around the ischial
tuberosities.
Sensor Configuration
Specifications for the sensor to be developed
required that external loading and tissue deformation
information be measured simultaneously. However,
the sensor also had to meet the limitations due to the
geometrical structure of the CASS, especially the
ultrasonic transducers. One of the first steps of the
project was to determine the configuration of the
sensor. Initially, two sensor configurations were
44 RERC ON WHEELCHAIR TECHNOLOGY

considered. One design allowed the measuring point
of the pressure transducer to coincide with that of
the ultrasonic transducers. An alternate configuration
was chosen and is shown in Figure 32. The chosen
configuration consists of a pressure sensor centrally
located in the swiveling head of an actuator element,
surrounded by four planar ultrasound transducers.
This design was chosen over others using custom
ultrasonic transducer configurations because of the
need to design a less expensive sensor using an
established technology with well-defined parameters.
The overall size of the sensor is 33.7 mm in diameter
by 7.2 mm high. Each ultrasonic transducer has as 5
mm diameter and a height of 7.2 mm. The pressure
transducer had previously been evaluated [Brienza
et al., 1996]. The sensor can detect pressure from 0 to
10 psi with 0.15% linearity and an ultrasonic echo
from 5 to 50 mm depth with an axial resolution
exceeding 0.5 mm.
with the compound sensors to also measure force and
tilt angle. Force is measured through bonded strain
gages mounted on a load-bearing cantilever beam
located in the actuator body. Vertical force applied
to the sensor head is transmitted by a piston with a
conical end that contacts the cantilever beam through
a concentrated load at the tip. The head of the sensor
is free to tilt and rotate on all support elements on
the CASS to allow the sensor head to be normal to
the tissue surface at all times. In order to determine
normal force, a linear potentiometer was added to
calculate the angle of tilt of the head. Figure 33 shows
the compound sensor with force and angle sensing
capabilities added.
FINAL REPORT: 1993-1998
Ultrasound
Transducers
Figure 32 - CASS with close-up of compound sensor.
An analysis of the preliminary data and a review
of the literature led us to a tissue model for use in
characterizing the buttocks soft tissue. Our’s and
other’s data suggests that it is necessary to model
buttock soft tissue as a viscoelastic material. The
model we chose to use is the quasi-linear viscoelastic
(QLV) model defined by Fung [Fung, 1981]. This
model required force-deformation data to
characterize the tissue. Rather than using the pressure
data to approximate the normal force applied to the
tissue, we chose to measure it directly. Thus, we
expanded the capability of the 9 support elements
45
Figure 33 - Sensor with ultrasound, pressure, force and tilt angle
measurement capabilities
Ultrasonic Transducer Specifications
The next step was the specification of an
appropriate ultrasonic transducer for the sensor.
Geometric constraints dictated that the diameter of
the ultrasonic transducer had to be less than 5 mm,
have a long cable to connect to the existing seating
system, and have good acoustic and electric
characteristics. For example, the transducer had to
provide an acoustic impedance match between the
transducer and soft tissue, and an electric impedance
match between transducer and emitting/receiving
amplifier. The transducer also needed to have high
sensitivity, a broad frequency bandwidth, narrow
pulse width, good axial resolution and low noise.
Among these are two tradeoffs, that between the
small size and high sensitivity, and the tradeoff

etween high emitting frequency with a long cable
and low noise.
Etalon, Inc manufactured two prototype PZT
ultrasonic transducers to our specifications. The
pertinent performance measures of the transducers
were quantified and the data indicated that the
transducers would meet the basic use requirements.
However, some parameters did not meet the design
requirements; sensitivity, ring down, bandwidth and
electrical impedance. These parameters affect the
resolution and sensitivity of the system. Since these
prototypes did not meet all our specifications, we
contacted a second manufacturer, Furuno Diagnostics
America, Inc. Furuno had recently commercialized a
novel composite ultrasonic transducer using a 1-3
ceramic-polymer structure. We requested that they
construct one of these composite transducers to meet
our needs. Specifications determined for the
ultrasonic transducer included a central frequency of
7.5 MHz, a frequency bandwidth more than 60%,
pulse width less than 0.2 µs and sensitivity more than
-22 dB. In addition, the coupling materials needed
between the sensor and body soft tissue must be
compatible with the pressure transducer. The
composite transducer was compared with the two
conventional PZT transducers. Table 1 summarizes
the performance results of the transducers.
Table 1. Sensor performance results
Parameters Composite PZT 1 PZT 2
Sensitivity (dB) -22 -31 -35
Bandwidth (%)
(-3 dB)
(-6 dB)
81.7
98.7
42.7
53.3
34.04
43.9
Central Frequency (MHz) 7.506 7.157 8.136
Pulse width ( ) 0.165 0.23 0.295
Axial Resolution (mm) 0.3 0.6 0.6
Cable Length (m) 3 2 2
The composite ultrasonic transducer, using 1-3
piezocomposite material was shown to have several
advantages. Its sensitivity is 9-13 dB higher than the
homogeneous PZT ceramic transducers. The
bandwidth is wider by 39-47.7% and pulse width is
reduced by more than 0.065 ms. The expanded
bandwidth improves the near-zone ultrasound
properties of the transducer. Thus, it improves the
ability to identify soft tissues just beneath the
subcutaneous skin layer, for example, connective and
adipose tissue. In addition, the axial resolution was
improved to 0.3 mm. Although the cable of the
composite transducer was 3 m, its performance was
much better than that of the conventional PZT
transducers with a 2 m cable. The composite
transducer has higher sensitivity, signal-to-noise ratio
and resolution than the conventional PZT ultrasonic
transducers.
Multi-channel Data Acquisition and Control
System Development
A 36-channel ultrasound system was integrated
into CASS. The main computer, a Gateway 2000-64G
Pentium Pro PC, sends control instructions using a
serial port to a slave computer that controls the
positions of the 11 by 12 sensor array using 8 axis
step motor controller. The pressure signals from the
sensor array are scanned into the main computer with
12 bit resolution by a data acquisition processor
(Oregon micro systems, Model-DAP1200E). At the
same time, the system triggers the ultrasound
transducer to emit an ultrasound wave. The system
also receives the ultrasonic echo from the soft tissue
interface and sends it to the main computer. A 100
MHz high-speed data acquisition card (CompuScope
250) was used for digitizing the ultrasound echo
signals with 8-bit resolution. Two CYDIO-96 digit I/
O units are used to select the channel measured or
controlled in the motor, pressure, and ultrasonic
arrays. The software for motor control was developed
using Turbo Pascal 7.0 for Windows 3.1 and other
components are implemented in LabView 4.0 for
Windows 95. The ultrasound system consists of a
synchronizing signal generator, 36 ultrasound
transducers, 36 emitting/receiving channels, Multiple
analog complexer and pre-amplifier, dynamic
compression amplifier, TGC control, a Compuscope
250-2M high speed data acquisition board, and the
Gateway 2000-64G Pentium Pro PC.
The ultrasound system specifications included the
following:
• Central frequency:7.5 MHz
46 RERC ON WHEELCHAIR TECHNOLOGY

• Detecting range:5 – 75 mm
• Emitting repeat frequency: 10 KHz
• Field scan repeat frequency: 278 Hz
• Bandwidth:> 75 %
• Axial resolution:0. 3 mm
• Signal Noise Ratio (SNR)> 45 dB
• TGC compensation:40 dB/80 dB (Option)
• Dynamic compression:60 dB
• Digit sampling frequency:25 / 50 /100 MHz
with 8 Bits resolution (option)
• Tracking precision:0.030 /0.0150 /0.0075 mm
(option)
System Software
The main program and all data collection software
were implemented in LabView 4.0 for Windows 95.
The motor control is resident on the slave computer
and was developed using Turbo Pascal 7.0 for DOS.
The thickness of each layer is obtained by tracking
the ultrasound echo signal peaks reflected from the
interfaces between different layers. Depending on the
echoes that need to be monitored, several tracking
windows can be used to measure the thickness of
these soft tissue layers during loading/unloading. In
the program, two echoes, from the fat-muscle and
muscle-bone interfaces, are tracked simultaneously
during loading.
In Vitro Testing
The composite ultrasonic transducer was used to
scan a pelvis in vitro. The system used is shown in
Figure 34. A cadaveric pelvis was submerged in a
water tank with the composite transducer mounted
onto a computer-controlled, 3-axis positioning
mechanism. The transducer scanned the pelvis at 6.35
mm increments. The ultrasound echoes were sent to
another computer, which then displayed a twodimensional
projection of the three-dimensional
contour. The computer sampled the echoes with a 50
MHz sample frequency. Typical results are shown in
Figure 35(a). The points in the figure are from the
ultrasound scan. The ischial tuberosities were clearly
identified. Figure 35(b) shows a typical echo from the
pelvis. The effect from the trigger pulse is less than
1.5 mm.
Figure 34 - System used to scan pelvis in vitro
(a.)
(b.)
Amplitude (V)
Y
1
0
-1
Trigger
Pulse
Echoes f rom
Pelv is
0 22.5 45
Distance (mm)
Figure 35- Scanning of the pelvis (a) 3-D Scatter Plot; (b)
Ultrasound Echoes
FINAL REPORT: 1993-1998
47

Additional in vitro testing was performed on
porcine tissue using a compound sensor integrated
into the CASS. This testing was performed for the
development and fine tuning of the signal analysis
software and control algorithm. Figure 36 shows the
experimental set up used for this in vitro testing. This
software development continued through this
evaluation and experimentation phase of the project.
Interface pressure and tissue thickness data were
successfully collected and repeatability was
demonstrated. After some fine-tuning, the system
was for in vivo data collection.
the deeper muscle layer. The total thickness is the
distance from skin surface to bone.
The results in Figure 37 demonstrated that the
system is capable of performing multiple parameter
measurements simultaneously. The system also
demonstrated good tracking capability, allowing
measurement of the changes in tissue thickness as
the tissue was compressed or during recovery. It also
demonstrated the ability to measure multiple tissue
layers simultaneously. In this data, we observed that
the muscle tissue had a larger percent deformation
than the first layer of tissue (first layer decreased 3.3%,
the muscle layer decreased 19.2%). This indicates that
the muscle layer over the IT deforms more than the
skin and fat under uniaxial loading.
Figure 36 - CASS system with integrated ultrasound system—In
vitro test setup
In Vivo Testing
In vivo tests began using able-bodied human
subjects to finalize the development of the software
and to begin to evaluate the in vivo performance of
the sensor. The testing was performed with
individuals seated on the CASS support surface. In
the initial tests, the compound sensor determined by
initial ultrasound scans to be directly beneath the
ischial tuberosity (IT) was moved sequentially
through three phases: indentation, recovery and hold.
A typical result is shown in Figure 37. The subject
was a 135 lb. female. Interface pressure and
ultrasound echoes were scanned into the computer
as the sensor moved. The total indentation was 6 mm.
Thickness 1 of Figure 37 includes the combination of
skin and subcutaneous fatty tissue. Thickness 2 is
Figure 37 - Results from initial in vivo testing
After the integration of the force and tilt angle
measurement capabilities, additional in vivo testing
occurred, as well as data analysis. A 140 lb male
subject was positioned on the CASS seating support
surface, with special care taken to locate the ischial
tuberosity (IT) directly above the 3 x 3 array of sensor
probes equipped with ultrasound capabilities. The
sensing probe directly beneath the IT was lowered
away from the tissue until a zero pressure state was
obtained. To conduct the stress-relaxation experiment,
the probe was raised at a constant indentation rate
(0.25 mm/sec), loading the tissue, to a maximum
upward probe travel of 10 mm. The probe was held
at its maximum indentation position for 50 sec, then
lowered away at the same constant rate to the initial
48 RERC ON WHEELCHAIR TECHNOLOGY

starting position. During the entire load holdrecovery
cycle, continuous force and bulk tissue
thickness measures were collected. Time of flight of
the ultrasound wave was used to determine tissue
deformation-time history.
Force time history data was used to characterize
soft tissue relaxation response according to the
reduced relaxation function, G(t), of the QLV model
[Fung, 1981]. Relaxation parameters were
approximated through curve fitting to experimental
data. The force-time history data (Figure 38(a) from
the load-indentation experiment was used to
approximate relaxation parameters. A comparison of
the G(t) calculated from the QLV model vs.
experimentally derived G(t) is shown in Figure 38(b).
The QLV reduced relaxation function appears to
adequately model experimental results.
Examples of data from additional pilot testing are
presented in Figures 39 and 40. Figure 39 shows the
force-time and deformation-time history and Figure
40 shows a force-deformation curve for a second male
subject. These results demonstrate that our system
can be used to measure the biomechanical properties
of buttock soft tissue in vivo and in situ.
(a.)
Normal Force (N)
9.000
8.000
7.000
6.000
5.000
4.000
3.000
2.000
1.000
Figure 39 - Force-time and deformation-time histories
0.000
Time
(b.)
G(t)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
G(t)exp
G(t) calc
Time
Figure 38 (a) Tissue Force Time History Response; b)
Experimental G(t) vs. predicted G(t)
Figure 40 - Force-deformation curve
The developed system can simultaneously
measure interface pressure, applied force, and tissue
deformation in multiple soft tissue layers. In vitro
analysis and in vivo evaluations of the ultrasound
system developed and integrated into the CASS show
that the system has the ability to investigate and
quantify the complex relationship between the
biomechanical parameters of buttock soft tissue. The
in vitro and in vivo testing demonstrated the dynamic
measurement capabilities of the CASS and ultrasound
system. The thickness of the soft tissue layers can be
measured using an automatic tracking of the
ultrasound echoes.
FINAL REPORT: 1993-1998
49

The in vivo pilot testing also showed that
acquiring and maintaining the ultrasound echoes was
challenging and took time and proper positioning of
the subject. The challenge was maintaining the
ultrasound echoes during the dynamic load cycle.
There are several variables affecting this, such as
subject posture, loading range, test site on the
buttocks, tissue deformation and the change in angle
of the sensor head. We found that we needed to learn
more from pilot tests before going forward with
clinical trials.
In addition to the tissue thickness data, additional
data on the mechanical response of tissue to external
loading can be obtained using this system. This
information can be used to investigate the
biomechanical properties of the tissue and allow more
accurate tissue characterization using existing tissue
models.
Recommended Future Research
Given the development and refinement of the
new above technology, clinical trials with various
populations should follow. These studies should
investigate the biomechanical properties of the
buttock soft tissue and allow more accurate tissue
characterization using existing tissue models. A
project has been funded by the Department of
Education to continue with the work begun by this
project. The project will determine the relationships
between the deformation of soft tissue and externally
applied load to determine differentiating intrinsic soft
tissue characteristics for spinal cord injured subjects
with and without past pressure ulcer pathology. If
successful at identifying differentiating
characteristics, the project will result in the
development of a tissue characterization based risk
assessment tool for individuals with spinal cord
injuries. An understanding of soft tissue
biomechanics for stratified patient populations will
also lead to improved clinical practice guidelines for
the prevention of pressure ulcers through improved
support surface design criteria.
Publications
Bertocci GE, Brienza DM, Karg PE, Wang J. In vivo test
protocol to determine soft buttock tissue relaxation
properties Accepted for publication ASME 1999 Summer
Bioengineering Conference Proceedings, Big Sky, Montana,
June 16-20, 1999
Brienza DM, Chung K-C, Brubaker CE, Wang J, Karg PE
and Lin CT. A system for the analysis of seat support
surfaces using surface shape control and simultaneous
measurement of applied pressures. IEEE Transactions on
Rehabilitation Engineering 1996; 4(2):103-113.
Wang J., Brienza DM, Brubaker CE, Ying-wei Yuan. Design
of an Ultrasound Soft Tissue Characterization System for
the Computer-Aided Seating System. Proceedings of the
RESNA ’96 Annual Conference, Salt Lake City, Utah, June 7-
12, 1996; 193-5.
Wang J, Ault T, Lin CT, and Brienza DM, Ultrasound
Measurements of Tissue Deformation Under Load, Dundee
‘97 - International Conference on Wheelchairs and Seating,
Dundee, Scotland, September 8-12, 1997.
Wang J, Brienza DM, Yuan Y-W, Karg PE, Brubaker CE. A
compound sensor for biomechanical analysis of load
bearings soft tissue. Proceedings of the RESNA ‘97 Annual
Conference, Pittsburgh, PA, June 20-24, 1997, 242-244.
Wang J, Brienza D, Karg P, Bertocci G. Biomechanical
analyses of buttock soft tissue using computer-aided
seating system. Proceedings of 20th Annual International
Conference of IEEE EMBS ‘98, Hong Kong, Oct 27-Nov 1,
1998, Vol. 20, Part 5/6, pp. 2757-2759.
References
Fung, Y., “Biomechanics: Material Properties of Living
Tissues.” Springer-Verlag, 1981, pp. 196 214.
50 RERC ON WHEELCHAIR TECHNOLOGY

TASK: S-3 NON-INVASIVE MONITORING OF
SPINAL/PELVIC ALIGNMENT
Investigators: Mark Malagodi, Douglas Hobson and Khondakar Mostafa
Collaborators: Tod Oblak and Michele Farneth
Rationale
Spinal deformity of individuals with spinal cord
injury, and other disabilities such as cerebral palsy,
muscular dystrophy or brain injury, can lead to loss
of sitting stability, loss of upper body function,
decrease in respiratory capacity, increased risk of
pressure ulcers, and increased pain and discomfort
[Hobson, et al. 1992], [Hobson, 1992]. Increasing
numbers of prescribers and suppliers of seating and
mobility devices are attempting to address these
problems. Unsupported claims are often made that
specialized seating inserts and cushions can reduce
or inhibit the onset of spinal and/or pelvic deformity
of individuals using wheeled mobility devices
(WMD). More importantly, service providers and
WMD users do not have a quantitative method of
assessing either the current status or the past history
of spinal/pelvic alignment while seated in their
WMD. Serial x-rays taken at 3-6 month intervals are
thought to expose clients to unacceptably high levels
of radiation exposure, especially if follow-up is
extended over a number of years. Determination of
pelvic/spinal alignment is recognized as one of the
most important variables in special seating. It is
important to be able to take the measurements while
the client is in the WMD, as the contribution of the
seating support to the spinal/pelvic alignment is
often the desired determinant.
Many non-invasive techniques have been applied
to detect and measure scoliosis and kyphosis of the
spine. Most of these techniques were developed to
detect idiopathic scoliosis through screening of school
age children. Among the more qualitative methods
developed are the Scoliometer [Amendt et al, 1990]
Back Contour Device Moir [Burwell et al 1983],
topography [Daruwall, 1985] and thermography
[Cooke, 1980]. The more quantitative techniques have
been surface topography [Pekelsky et al], light beam
scanning (ISIS) [Turner-Smith, et al 1986], and
ultrasonic digitization [Letts et al 1988]. All of these
techniques have been compared to the “gold
standard” of orthopedic radiographic spinal
measurement, the Cobb method. Some techniques
correlate better than others with the conclusion by
several investigators that the frequency of
radiographs can be reduced, but not eliminated from
spinal monitoring, especially for scoliotic curves that
have progressed beyond a 30 0 Cobb angle. Good
correlation between spinous process mapping and the
Cobb measurements was demonstrated by [Letts et
al. 1988], for curves over 30 0 . Furthermore, they were
able to demonstrate that an acceptable correction
factor can be achieved for curves under a 30 0 Cobb
angle.
The major limitation of these techniques is that
they require direct exposure of the spine to the
measurement instrumentation, preferably in the erect
standing position. Radiographs require medical
approval, are costly, and run the risk of excessive
exposure. A literature review was unable to identify
any technique or instrument that could measure and
record spinal/pelvic alignment of a person seated in
their WMD.
RF Transmitter Control Unit with Transmitters
taped to Prominent Spinal Landmarks
Figure 41. Schematic of radio frequency method of determining
spinal pelvic position of a subject seated in his/her personal
wheelchair.
FINAL REPORT: 1993-1998
51

Goals
To research and develop a quantitative method,
including reasonably priced instrumentation, to
monitor changes in spinal/pelvic alignment of a
wheelchair seated person at risk of increased
deformity.
Outcome Summary
This task was transitioned into the technology
transfer phase at the end of Year II (7/31/95). No
further RERC funds were expended on this task. A
partnership was formed with ARTSCO, Inc.
(Pittsburgh, PA) to continue the prototype
development of the measurement tools. An NIH/
NCMRR SBIR technology transfer grant was awarded
to ARTSCO to further the development this
technology. In addition, a technical report entitled,
Spinal/Pelvic Alignment Monitoring of Wheelchair
Users, which details the research findings, has been
prepared and is available from the RERC upon
request.
Phase I research began in October 1997. Under
the support of the NIH/SBIR, ARTSCO collaborated
with the Antenna Lab at the Virginia Tech University
to design small flexible patch antennas that could be
placed on landmarks of the spine. Prototype antennas
were completed in February 1998. While Virginia Tech
was developing the antennas, ARTSCO developed
the supporting electronics system to test the feasibility
of measuring spinal alignment through radio
frequency signals. A signal generator capable of
producing a 900MHz sine wave and a vector
voltmeter capable of measuring small phase
differences were purchased. The laboratory was set
up with three receiving antennas, and one
transmitting antenna. A special calibration jig was
developed by ARTSCO to move the transmitting
antenna in 1mm increments in each dimension (X, Y,
Z). Electronic switches and a computer software
program were written to measure the phase difference
between each pair of receiving antennas. Upon
acquiring the prototype antennas from Virginia Tech,
testing of the system began at the ARTSCO facility.
To date, testing conducted at the ARTSCO
laboratory has not succeeded in demonstrating the
ability to calibrate the actual movement of the
transmitting antenna to the movement measured
through the RF phase difference technique. The most
likely cause of the error is unwanted signal reflections
from objects, walls, ceilings and floors in the
laboratory. Research is continuing at the ARTSCO lab
to determine the cause of errors and remedy the
situation.
Recommended Future Research
At this time research should focus on determining
the cause of the inability to calibrate. Testing the
system in a chamber that absorbs all RF signals would
eliminate unwanted reflections, and therefore test the
theory postulated above. At this time ARTSCO is
attempting to arrange a test with a center that has
this type of chamber. Once calibration is achieved,
human tests should be initiated. An X-ray should first
be taken with the antennas in place on the spine to
determine if the antennas are indeed over the bony
landmarks of interest. Secondly tests should be
undertaken to determine whether the measurements
made of the antenna locations match the actual
locations of the antennas on the spine.
Publications
Malagodi, M.D., “Technical Identification of a Non-
Invasive Spinal/Pelvic Monitoring System for Individuals
Seated in Personal Wheeled Mobility Devices”. Poster
Presentation. 17th Annual RESNA Conference, Nashville,
TN. June 1994.
References
Hobson DA. & Tooms RE. (1992) Seated Lumbar/Pelvic
Alignment A Comparison between Spinal-cord Injured and
Non-injured Groups. Spine; 17:293-298.
Hobson DA. (1992) Comparative effects of Posture on
Pressure and Shear at the Body-Seat Interface. J Rehabil Res
Dev ; 29(4).
Amendt LE, Ause-Ellias KL, Eybers JL, et al. (1990) Validity
and Reliability of the Scoliometer. Phys Ther;70:108-117.
Burwell RG, James NJ, Johnson F, et al. (1983) Standardized
Trunk Asymmetry Scores: A Study of Back Contour in
Healthy School Children. J Bone Joint Surgery (Br); 58:64-
71.
Daruwalla US, Balasubramaniam P. (1985) MoirÈ
topography in scoliosis - Its accuracy in detecting the site
52 RERC ON WHEELCHAIR TECHNOLOGY

and size of the curve. J Bone Joint Surg; 67B:211-213.
Cooke ED, Carter LN, Pilcher MF. (1980) Identifying
scoliosis in the adolescent with thermography. Clin Ortho;
148:172-176.
Neugebauer H, Windischbauer G. (1987) School screening:
A New Pilot Study. Stokes IAF, Pekelsky JR, Moreland MS,
eds. Surface Topography and Spinal Deformity. Stuttgart,
Federal Republic of Germany: Gustave Fischer Verlag
GmbH & Co KG; pp. 177-186.
Turner-Smith AR, Harris JD. ISIS (1986) An automated
shape measurement and analysis system. In: Harris JD,
Turner-Smith AR, eds. Surface Tomography and Spinal
Deformity. Stuttgart, Federal Republic of Germany:
Gustave Fischer Verlag GmbH & Co KG; pp. 31-38.
Letts M, Quanbury A, Gouw G, Kolsun W, Letts E (1988)
Computerized Ultrasonic Digitization in the Measurement
of Spinal Curvature. Spine; 13: 1106-1110.
FINAL REPORT: 1993-1998
53

Rationale
TASK: S-4 THE EFFECTS OF POSITIONING ON
INDIVIDUALS WITH C5-C7 QUADRIPLEGIA
Investigators: Michael Boninger, Tracy Saur, Elaine Trefler, Douglas Hobson
Collaborators: Allan sampson
Persons with high level spinal injury have been
observed to develop postural deformities of their
spines and pelvis after prolonged use of wheelchairs.
This task addresses the questions as to whether the
deformity progresses over time, causes pain, and
whether it adversely effects pulmonary function and
life satisfaction.
Goals
1. Determine the relationship of posture (kyphosis
& scoliosis) between individuals with new onset
of C5-C7 spinal cord injury versus long term onset
of cervical spinal cord injury.
2. Determine the correlation of posture with
pulmonary function, pain, and life satisfaction.
Methods Summary
Recruitment
Subjects were recruited through searching the
patient database at a freestanding rehabilitation
hospital. In order to qualify for the study individuals
had to have a traumatic spinal cord injury (SCI)
resulting in tetraplegia and use a wheelchair as their
primary means of mobility. Two distinct groups were
recruited: individuals 1 to 3 years post injury —
relatively new tetraplegia (NT) and individuals 10 to
20 years post injury — relatively old tetraplegia (OT).
The control subjects (C) were recruited after the
testing on individuals with tetraplegia was
completed. A deliberate attempt was made to recruit
individuals matched with the tetraplegia groups for
age, sex, height and weight.
Posture Assessment
All subjects were seated in a wheelchair specially
modified to allow unobstructed A-P and lateral
radiographs to be taken. Each radiograph was read
by a single investigator who was blinded to the group
assignment of subjects. Scoliosis was measured using
the Cobb technique { Weissman, et al. 1986}. Kyphosis
was measured using the technique described by {Fon
et al. 1980}. The control group was included to allow
comparison in radiographic measures between
individuals with and without paralysis.
Questionnaires
As part of each subject’s evaluation a series of
standardized questionnaires was completed. These
questionnaires were reviewed with the subjects
individually to insure adequate completion. In
addition to the standardized questionnaires listed
below, subjects were asked questions related to back
and neck pain, decubitis formation and upper
extremity pain. Each subject was given the Center for
Epidemiological Studies - Depression Scale (CES-D),
{Radloff, 1977), the Life Satisfaction Index Assessment
(LSIA) {Neugarten et al. 1961}, and the Craig
Handicap Assessment and Reporting Technique
(CHART) {Whiteneck et al, 1992}. In addition to
asking yes and no questions related to back and arm
pain, each subject was given the McGill Pain
Questionnaire (MPQ).
Outcomes Summary
Characteristics
A total of 10 subjects were recruited into each
group. Using an independent sample t-test, no
significant differences were found with regards to
age, height, and weight between the NT and OT
groups. In addition, no significant differences with
respect to age, height and weight were found between
the combined NT and OT group and C group. The
Mann-Whitney U test found no differences in injury
level between OT and NT. As expected, a significant
difference was seen between the NT and OT group
with respect to years out from injury.
54 RERC ON WHEELCHAIR TECHNOLOGY

Posture, Aging, and Pain
No differences were found between the NT and
OT groups in either measures of kyphosis or scoliosis.
The C group was found to have significantly less
scoliosis and kyphosis than the combined NT and OT
groups. The results are summarized in Table 2. Nine
of the 20 subjects with tetraplegia reported back pain
and 10 of the 20 subjects reported upper extremity
pain. No significant differences were seen in kyphosis
and scoliosis in those reporting pain and those not
reporting pain. No significant relationship was found
between pain and radiographic measures.
Discussion
This is the first reported study to radiographically
measure kyphosis and scoliosis in a group of
individuals with tetraplegia. Not surprisingly,
individuals with tetraplegia were found to have a
greater degree of seated kyphosis and scoliosis than
a control group without paralysis. This study did not
find a greater degree of spinal curvature in
individuals further out from an SCI. This contradicts
what has generally been accepted by professionals
involved in seating and positioning. One possible
explanation for this finding is that our subjects were
not far enough out from their initial SCI to develop
progressive spinal deformity. An important finding
of this study is that individuals who were only two
to three years out from an SCI had significant spinal
deformity. It may be that a kyphotic and scoliotic
posture are assumed early and then are not
progressive. If this is the case, early interventions will
be needed to prevent problems later.
This study found no association between spinal
deformity and pain, perceived function or depression.
Only one previous study has addressed the
association between pain and spinal deformity. This
study by Gertzbein did find an association between
pain and kyphosis in individuals with a spinal
fracture at the thoracic and lumbar levels, but it was
not statistically significant. It is important to note that
our subject population was relatively young and all
less than 20 years out from SCI. In addition, all of the
subjects were recruited from an outpatient SCI followup
clinic. If the population had included individuals
who were more than 20 years out from injury, or who
did not receive specialized routine care, the results
may have been different.
Recommended Future Research
Larger longitudinal studies are needed to
determine if pain does become a problem in
individuals with significant kyphosis and scoliosis
as they age, and to more definitively examine the
progression of kyphosis and scoliosis with aging.
Publications
Boninger ML, Saur T, Trefler E, Hobson DA, Burdette R,
and Cooper RA: Postural Changes with Aging in
Tetraplegia, Archives of Physical Medicine and Rehabilitation,
Vol. 79, No. 12, pp. 1577-1581, December 1998.
Boninger ML, Saur T, Trefler E, Hobson D, Burdett R, and
Cooper RA: Postural Changes with Aging in Tetraplea,
Proceedings 21 st Annual RESNA Conference, Minneapolis,
MN, pp. 155-157, 1998.
Saur T, Boninger ML, Hobson D, and Trefler E: A
Comparison of Individuals with New C5-7 Injuries vs.
Individuals with Old C5-7 Injuries, Proceedings 20 th Annual
RESNA Conference, Pittsburgh, PA, pp. 217-218, 1997.
References
Fon GT, Pitt MJ, Thies AC, Jr.: Thoracic kyphosis: range in
normal subjects. AJR 1980;American Journal of
Roentgenology. 134:979-983.
Gertzbein SD: Scoliosis Research Society. Multicenter spine
fracture study. Spine 1992;17:528-540.
Neugarten BL, Havighurst RJ, Tobin SS: The measurement
of life satisfaction. J Gerontol 1961;16:134-143.
Radloff LS: The CES-D scale: A self-report depression scale
for research in the general population. Appl Psychol Meas
1977;1:385-401.
Weissman BNW, Sledge CB: The Lumbar Spine, in
Orthopedic Radiology. Philadelphia, PA, W.B. Saunders
Company; 1986:288-294.
Whiteneck GG, Charlifue SW, Gerhart KA, Overholser JD,
Richardson GN: Quantifying handicap: A new measure
of long-term rehabilitation outcomes. Arch Phys Med
Rehabil 1992;73:519-526.
FINAL REPORT: 1993-1998
55

TASK: S-5 CUSTOMIZED WHEELCHAIR SEATING FOR
POPULATIONS WITH CHANGING NEEDS
Investigators: Elaine Trefler, Dalthea Brown and Douglas Hobson
Rationale
Statistics show that traumatic brain injuries
incurred each year number around two million.
Outcomes can vary from death or prolonged coma
to only mild deficits that have minimal impact on the
patient and this family. The likelihood or extent of
the impairment is difficult to predict soon after the
injury. However, it is during this time that clinicians
and seating specialists are expected to make a
recommendation regarding the equipment for seating
and mobility.
There are few guidelines that assist clinicians to
determine when the best time is to provide seating
intervention and how aggressive to make the
intervention considering the likelihood of
improvement. There is no information about the
natural history of recovery as it relates to wheelchair
seating intervention. As well, there are no measures
of outcomes related to seating intervention for this
population.
Goals
To provide clinical guidelines for seating and
mobility intervention for persons with closed head
injuries (CHI) over the natural history of the condition
for a two-year post injury period.
Methods Summary
An instrument was developed to measure the
complexity of seating and mobility intervention. It
measured the correlation between recovery and the
seating technology needs of an individual who has
suffered a CHI. A draft of the tool was used to
establish both content validity and interrater
reliability. The instrument proved very complex and
interrater reliability was not acceptable. The tool was
redesigned and the process repeated until the tool
could be administered successfully by any one of
three therapists assigned to the project.
Items for documentation included
• make and model of wheelchair and seating
system (this included a system to indicate the
complexity of each component of the system so
measures over time would indicate improved
motor skill as indicated by less complex seating
and mobility scores),
• functional skills,
• sitting posture while in their wheelchair,
• physical motor status (tone, strength, structure,
reflexes),
• anthropometrics, and
• comfort/satisfaction survey (subject and
clinician).
Outcomes Summary
A seating technology assessment tool (STAT) was
developed in collaboration with a physical and
occupational therapist from the RERC staff and the
UPMC Rehabilitation Hospital. It records the types
and numbers of seating system components that an
individual required to maintain an upright posture
while sitting against gravity. It uses an ordinal rating
system in which the components were ranked from
the most to the least amount of support provided.
The STAT is divided into technology and subject
related data. The subject data includes information
gathered regarding the individual’s posture, reflex
and functional information skills. The technology
data is broken down into those relating to the seat
and back components. Preliminary validation was
performed with two physical therapists and one
occupational therapist. The revised tool was
administered initially to three subjects and follow up
was done with one of the subjects that remained a
wheelchair user. The two other subjects improved in
function and became ambulatory.
56 RERC ON WHEELCHAIR TECHNOLOGY

Problem Encounters
Final data collection took place over a nine-month
period, which was insufficient to establish a
relationship between natural recovery and seating
technology. Critical time was missed during the acute
recovery phase, as clients were not recruited until they
entered the rehabilitation phase of their recovery. As
well, several specific items such as degree of tilt of
the chair had to be added to the data collection tool,
as they were specifically indicative of how well and
how long a client could sit upright, which in turn was
an indication of the return of sitting tolerance.
Recommended Future Research
Further refinement and validation of the tool
needs to be performed. The tool should then be used
with a larger sample of subjects as part of a clinical
outcome study.
Publications
Documentation in the form of a case study is in
process and will be submitted for publication.
FINAL REPORT: 1993-1998
57

III. IMPROVED WHEELCHAIR TRANSPORTATION
♦T-1 DESIGN CRITERIA FOR TRANSPORT WHEELED MOBILITY DEVICES
♦T-2 DEVELOPMENT OF WHEELCHAIR SECUREMENT INTERFACE CONCEPTS
♦T-3 DEVELOPMENT OF DOCKING TYPE SECUREMENT DEVICES
♦T-4 RESEARCH COORIDINATION RELATED TO STANDARDS DEVELOPMENT FOR
WHEELCHAIR TRANSPORTATION
58 RERC ON WHEELCHAIR TECHNOLOGY

TASK: T-1 DESIGN CRITERIA FOR TRANSPORT WHEELED
MOBILITY DEVICES
Investigators: Gina Bertocci, Kennerly Digges, Douglas Hobson
Collaborators: Linda vanRoosmalen, Dongran Ha, Stephanie Szobota
Rationale
Motor vehicle seats are designed to protect their
occupant in a crash. Wheelchairs designed for normal
mobility are not commonly designed to be
crashworthy. This task was intended to ultimately
provide manufacturers with design guidance for
producing wheelchair products intended to serve as
seats in motor vehicles.
Goals
1. Develop design strategies and criteria for safer
transport of Wheeled Mobility Devices (WMDs).
2. Facilitate the commercial availability of transport
WMDs manufactured in accordance with
nationally recognized industry standards.
Methods Summary
This task has relied upon a combination of
computer simulation and experimental testing.
Computer crash simulation models were developed
and validated for use in the study of factors
influencing injury risk of wheelchair occupants in a
crash. A wheelchair transportation-specific Injury
Risk Assessment method was developed and used
in the comparison of injury risk associated with
various wheelchair transportation scenarios.
Outcomes Summary
• Developed and validated a production
powerbase, dynamic model using crash
simulation software.
• Developed and validated a dynamic model of a
conventional production power wheelchair.
• Investigated the influence of rear securement
point location on frontal crash safety using
developed conventional power wheelchair and
powerbase models.
• Defined “transport wheelchair” design criteria
using computer simulation.
• Developed an Injury Risk Assessment Method
appropriate to the WMD transportation crash
environment.
• Evaluated injury risk associated with various
securement configurations through the use of the
developed Injury Risk Assessment Method.
• Evaluated the affects of shoulder belt anchor
location on wheelchair crash safety.
• Surveyed 80 various types of WMDs and
developed characteristics database appropriate for
use in WMD transportation design and research.
• Through the use of the WMD database, redefined
the ISO/SAE surrogate test wheelchair to better
represent production powered wheelchairs.
• Awarded a “Wheelchair Integrated Restraint
System” STTR grant to investigate the integration
of a total occupant restraint system.
• Demonstrated the occupant protection
advantages associated with a wheelchair
integrated restraint as compared to vehiclemounted
restraint systems through the use
computer simulation and the developed Injury
Risk Assessment method.
• Developed a psuedo-dynamic test to evaluate the
crashworthiness of commonly used caster
assemblies.
• Evaluated the crashworthiness of common
wheelchair caster assemblies using developed test
methods.
• Evaluated the crashworthiness of commercially
available wheelchair seating systems through the
use of FMVSS 207 ‘Seating Systems’ test methods.
FINAL REPORT: 1993-1998
59

Drop
Wghts.
Applied
Force
Caster
Test
Fixture
Figure 42 – Dynamic Drop Testing of Caster Assemblies
Figure 43 – FMVSS 207 Seating System Testing of Wheelchair Seats
Recommended Future Research
Future research efforts will focus on the
crashworthiness of wheelchairs and their components
in rear and side impact scenarios. Additional efforts
related to the study of frontal impact will concentrate
on the development and validation of a computer
model to predict occupant submarining when seated
in a wheelchair. Various seating characteristics will
be evaluated to determine their influence on injury
risk and in particular submarining.
Publications
Bertocci GE, Digges K, Hobson D, Development of
Transportable Wheelchair Design Criteria Using Computer
Crash Simulation. IEEE Transactions on Rehabilitation
Engineering, Vol 4, No 3, Sept. 1996: 171-181.
Bertocci GE, Digges K, Hobson DA, Shoulder Belt Anchor
Location Influences on Wheelchair Occupant Crash
Protection. Journal of Rehab Research and Devel, Vol 33,
No 3, July 1996:279-289.
Bertocci GE, Karg, P, Hobson D, Wheeled Mobility Device
Database for Transportation Safety Research and
Standards. Assistive Technology, Vol 9.2, 1997.
60 RERC ON WHEELCHAIR TECHNOLOGY

Bertocci GE, Esteireiro J, Cooper RA, Young TM, Thomas
C, Testing and Evaluation of Wheelchair Caster Assemblies
Subjected to Dynamic Crash Loading. To appear in Journal
of Rehab Research and Development, Vol 36, No. 1, January
1999.
Bertocci GE, Digges, K, Hobson DA, Computer Simulation
and Sled Test Validation of a Powerbase Wheelchair and
Occupant Subjected to Frontal Crash Conditions. To appear
in IEEE Trans Rehab Engr, Vol 7, No 2, June 1999.
Bertocci GE, Digges, K, Hobson DA, Development of a
Wheelchair Occupant Injury Risk Assessment Method and
Its Application in the Investigation of Wheelchair
Securement Point Influence on Frontal Crash Safety.
Conditionally accepted in IEEE Transactions on
Rehabilitation Engineering, Nov. 1997.
Digges K, Bertocci GE, Application of the ATB Program to
Wheelchair Transportation. Technical Report #3,
University of Pittsburgh RERC, Nov 1995.
Bertocci GE, Hobson D, The Affects of Securement Point
Location on Wheelchair Crash Response. Proceedings of
the RESNA ‘96 Annual Conference RESNA Press,
Washington DC, June 1996.
VanRoosmalen, L, Ha, D, Bertocci, G, Karg, P, Szobota, S,
An Evaluation of Wheelchair Seating System
Crashworthiness Using Federal Motor Vehicle Safety
Standard (FMVSS) 207 Testing, Submitted to RESNA ’99
Conf, Dec, 1998.
Bertocci GE, Esteireiro J, Cooper RA, Young TM, Thomas
C, Testing and Evaluation of Wheelchair Caster Assemblies
Subjected to Dynamic Crash Loading. Proceedings of RESNA
‘98 Annual Conference, June 1998.
Karg P, Bertocci GE, Hobson DA, Status of Universal
Interface Design Standard for Mobility Device Docking on
Vehicles. Proceedings of the RESNA ‘98 Annual Conference,
June 1998.
Van Roosmalen L, Bertocci GE, Karg PE, Young TM, Belt
Fit Evaluation of Fixed Vehicle Mounted Shoulder Restraint
Anchor Across Mixed Occupant Populations. Proceedings
of the RESNA ‘98 Annual Conference, June 1998.
Bertocci GE, Development of Transportable Wheelchair
Design Criteria Using Computer Crash Simulation.
Proceedings of 1998 Articulated Total Body Modeling
Conference, April 1998.
Bertocci GE, The Affects of Shoulder Belt Anchor Position
on Wheelchair Transportation Safety. Proceedings of the
RESNA ‘95 Annual Conference. RESNA Press, Washington,
DC, 1995: 311-313.
Bertocci GE, Karg P, Hobson D, Wheelchair Classification
System and Database Report, Technical Report #6,
University of Pittsburgh RERC on Wheelchair Mobility,
Pittsburgh, PA 1996.
Bertocci GE, Digges K, Hobson D, The Affects of
Wheelchair Securement Point Location on Occupant Injury
Risk. Proceedings of the RESNA ’97 Annual Conference,
RESNA Press, Washington DC, Jan 1997. Recipient of 1997
RESNA/Whitaker Scientific Paper Competition Award.
Bertocci GE, Karg PE, Survey of Wheeled Mobility Device
Transport Access Characteristics. Proceedings of the
RESNA ’97 Annual Conference, RESNA Press, Washington
DC, Jan 1997.
Bertocci GE, Ph.D. Dissertation: The Influence of
Securement Point and Occupant Restraint Anchor Location
on Wheelchair Frontal Crash Safety, July 1997.
FINAL REPORT: 1993-1998
61

TASK: T-2 DEVELOPMENT OF WHEELCHAIR SECUREMENT
INTERFACE CONCEPTS
Investigators: Gina Bertocci, Jules Legal, Douglas Hobson and Patricia Karg
Rationale
Wheelchairs, their securement devices, occupant
restraints and transport vehicles all must function as
a system, if individuals are to safely and
independently use both public and personal vehicles
while remaining seated in their wheelchairs.
Currently, securement systems for wheelchairs are
often inadequately applied, are time consuming to
use, and require the involvement of a vehicle operator
or an attendant. A universal solution is needed that
provides independent, quick, and safe securement.
Improving accessibility and safety relies upon
standardized methods being developed and adopted
for interconnecting the respective technologies. The
successful development of new docking-type
securement devices, that eliminate several of the
disadvantages of commonly used belt-type devices,
depends upon standardized ways of interconnecting
the wheelchair with vehicle-mounted securement
hardware. The adoption and promulgation of a
universal interface device (UID) standard for docking
devices can ultimately mean that a person can access
and have their wheelchair secured in any transport
vehicle, in a manner offering equivalent safety to
other riders seated on the vehicle.
Goals
Universal Interface Concept
The goal of this project was to facilitate the
adoption of a universal interface device standard
developed by a trans-industry effort. The approach
chosen to reach this goal was as follows:
1. research, develop and evaluate design
specifications for universal interface hardware
designs that meet constituency-defined needs;
2. conceptualize universal interface device concepts
that will foster compatibility between present and
future technologies; and
3. foster acceptance and inclusion of concepts and
design specifications in national and international
standards development.
Personal Wheeled
Mobility Devices
Public and Private
Transport Vehicles
Figure 44 - Illustration of Universal Interface Docking concept
62 RERC ON WHEELCHAIR TECHNOLOGY

Standardization of the geometry and location of
the docking hardware on wheeled mobility devices
will allow industry to design and produce vehiclemounted
docking securement devices that are
universally compatible.
Methods Summary
The first step in the process was to characterize
wheelchair frames and determine the feasibility of
adding a common universal attachment. A database
of wheelchair frames was developed in this process.
This work helped to identify the optimal location for
placement of the hardware, as well as necessary clear
zones surrounding the hardware. Another initial step
was to gather information on the state of the
technology in transport vehicles and securement
design. In addition, consensus among the involved
constituents on the need for a UID had to be
established. Reaching agreement on a UID for
docking devices between diverse interests such as
wheelchair users, wheelchair manufacturers, tiedown
manufacturers, vehicle manufacturers and
transporters is a challenging undertaking. Focus
group meetings, one involving wheelchair users and
the other involving industry, were held to this end.
Once it was established that there was a need for a
UID standard, the two groups worked toward
defining and prioritizing the design criteria.
Establishment and priority ranking of the criteria
and definition of the clear zones was only the first
step. To be adopted universally and eventually
promulgated through national and international
industry standards, feasibility of the approach had
to be demonstrated. Therefore, a series of potential
interface hardware designs meeting the criteria were
developed and tested. To ensure that the designs met
the defined criteria, the RERC, as in other tasks, used
the Quality Function Deployment (QFD) design
proces. The QFD is a design tool that involves a
multidisciplinary design approach. It is a process for
translating customer requirements into appropriate
technical requirements at each stage of the product
development process. This process allows for
proactive quality control and focuses on planning and
problem prevention, rather than problem solving
down the road. The process is accomplished through
a series of matrices and charts that deploy customer
requirements and related technical requirements
through the product development phases. The first
step of the QFD process involves developing the
matrix known as the “House of Quality”, which is a
basic design tool. The defined and ranked design
criteria and identified clear zones were used as inputs
to the QFD design matrix.
Several conceptual hardware configurations
were designed and fitted to test wheelchairs (Figure
44a&b). The initial concepts were evaluated through
feedback from users and industry, strength testing
and compatibility testing with production
wheelchairs. The evaluations and feedback led to a
final design that was further evaluated. The latter
design was incorporated into a draft standard and
submitted to an independent standard development
group (ANSI/RESNA) for further development and
creation of a standard. Details of the outcomes of
this process are presented below.
Outcomes Summary
Design and Development
The concept of the universal interface was first
presented in the 1995 RESNA Proceedings {Hobson,
1995}. Initial development activities were reported in
the 1997 RESNA Proceedings {Karg, 1997}. The initial
activities focused on an investigation of the array of
wheelchair frames in an effort to categorize them and
determine commonalties. A survey data form of 45
data points was developed to record relevant
wheelchair characteristics, and a database was
constructed to maintain and organize the information
{Bertocci, 1996; Bertocci, 1997}. This survey provided
important information such as the location of the
center of gravity and the nature of the existing frame
configurations with respect to the ease of adding a
common universal attachment design for the purpose
of docking securement on motor vehicles. This was
used to identify the optimal location for placement
of the hardware, as well as the necessary clear zones.
Additional efforts included gathering information
on flip-up bus seats, current securement
configurations and wheelchair compartment designs
on vehicles. Current docking devices were also
FINAL REPORT: 1993-1998
63

obtained for evaluation. Visitations to leading
securement companies were made, providing insight
into the current state of the technology.
The next step was to organize and host industry
meetings and consumer focus groups to identify the
desire and need for a universal design standard, and
to identify design specifications. Two industry
meetings have been held that included wheelchair
manufacturers, securement manufacturers, vehicle
manufacturers, and transporters. A focus group
comprising manual and power wheelchair users that
use public and/or private transportation was held
in the time between the two industry meetings.
There was overwhelming agreement on the need
for a universal interface for docking devices and that
a design standard should be pursued. To that end,
the two groups then generated lists of design criteria
for the universal interface; a list of 19 criteria resulted
from the two groups. The eight criteria listed below
were included in the top 6 ranked criteria of the
consumer group and/or the industry group. The first
two bullets were ranked first and second priority by
both groups independently, and the third and fourth
appeared on both lists. The remaining four appeared
on only one of the ranked lists as indicated by either
an “I” (industry) or a “C” (consumer) following the
criterion. These criteria and their ranking provided a
target for the ensuing research effort. These results
have been disseminated to two standards
development groups.
The partial listing of the design criteria for the
universal interface, as referenced above, is as follows.
• Meet all applicable safety standards (I, C)
• Promote independent securement (I, C)
• Maintain original function of wheelchair (e.g.,
folding, feel, maneuverability) (I, C)
• Accommodate all wheelchair types and sizes that
are used as motor vehicle seats (I, C)
• Compatible with all vehicle types that transport
passengers seated in wheelchairs (driver docking
and fold-down seats accommodated) (C)
• Promote quick securement time (less than 1
minute from being positioned at the securement
station to securement) (C)
• Does not preclude use of existing tie-down and
occupant restraint systems (I)
• Allow retrofit to existing wheelchairs (I)
The design criteria were used to implement the
Quality Function Deployment (QFD) design process.
This method was used to assure the needs and desires
of all project stakeholders have been considered and
are effectively incorporated into the design of the
hardware. Finally, several hardware designs were
developed and some fabricated for consideration and
evaluation. Clear zone requirements with respect to
the wheelchair to allow access to interface hardware
were also established. Industry and consumer
representatives indicated they would like the
feasibility of the designs evaluated before the
standard was created and subsequent work was
performed to this end. The evaluation of the proposed
hardware designs and status of these efforts were
reported at the 1998 RESNA Conference {Karg, 1998}.
The UID standard will provide the basis by which
all involved industries can design and produce
compatible wheelchair securement products. Design
of the docking devices will be limited only in that the
wheelchair hardware (i.e., the universal interface)
geometry, location in space, and surrounding
clearance will be defined. The industry meetings
centered around the debate of two configurations of
a UID located on the lower rear portion of the
wheelchair. One configuration, that was favored after
the second industry meeting, is two vertically
oriented structures (Figure 44a), aligned side by side
{Karg, 1997}. However, the discussions in the third
meeting (June 1997) tended to return to the appealing
approach of having a horizontal bar across the rear,
similar to the grab bars offered on several scooters
(Figure 44b). Evaluations of these two configurations
revealed several pros and cons of each (detailed
below). The horizontal bar proved better for ease of
retrofit to existing wheelchairs however, did not
provide a reaction point to prevent rear or end
wheelchair rotation during a crash. Thus, two
horizontal bars may be necessary. The vertical
configuration would allow for the needed stability,
however appeared to be more difficult to retrofit and
integrate into existing wheelchair designs.
64 RERC ON WHEELCHAIR TECHNOLOGY

a)
b)
Figure 44 – Conceptual designs: (a) vertical concept (b)
horizontal concept
Evaluation
Compatibility testing: Field tests were performed
to evaluate the compatibility of the vertical and
horizontal design configurations with existing
production wheelchairs to assess the ease of retrofit,
as well as the ease of incorporation in future designs.
Approximately a dozen wheelchairs representing the
different classes, including pediatric wheelchairs,
were evaluated. In general, the wheelchairs surveyed
more readily accommodated the horizontal interface.
However, in some cases, overall wheelchair length
was increased, which is undesirable. The problems
generally found with the vertical configuration were
battery box interference in placement, and inadequate
distance between the battery box and wheel for access
of the interface. In addition, the various wheelchair
widths dictated various spacing of the vertical
interface components, placing more demands on the
docking system design.
Dynamic testing: The vertical interface design was
dynamically tested for strength using a drop test jig
to simulate dynamic conditions for a 20 g crash with
a 200-220 lb wheelchair and a 50% male occupant.
The load was applied perpendicular to the 3/4” solid
aluminum tubing making up the vertical interface
component. With successive testing at these loads
only slight deformation occurred.
Reaction point analysis: Since the primary concern
with using a rear-only securement was wheelchair
rotation, crash simulations were performed to analyze
various interface configurations. The simulations use
a surrogate wheelchair used in sled testing of belttype
securement systems. The surrogate was
designed to represent a standard power wheelchair
occupied by a 50% male wearing an integrated
restraint. The simulations were not validated with
sled testing, but could be used for comparative
purposes. Front wheel excursions at time of 250 msec
during the rebound phase of a frontal crash were used
to characterize the crash response of the wheelchair.
Initially a 1” diameter horizontal bar was placed 11”
above the floor (at the center of gravity of the
wheelchair) and had an excursion of 6.9”. Then two
horizontal circular bars were tested separated by 5”
and 2” and had excursions of 3.5” and 3.9”,
respectively. The analysis emphasized the need for a
second reaction point to prevent excessive wheelchair
rotation when securing the wheelchair at the rear only.
The results showed that a double horizontal bar
would provide the desired second reaction point.
Based on the information and research to date,
the group at the June 1997 industry meeting discussed
the relative merits of the vertical versus the horizontal
interface configurations. The vertical configuration
had been chosen as the most promising in previous
meetings. In light of new data, the group decided
the horizontal configuration looked promising as well
and that it should be further researched by the RERC
FINAL REPORT: 1993-1998
65

team, especially with respect to stability and
wheelchair rotation.
a)
Hybrid interface design and evaluation
The hybrid interface (Figures 45 and 46) appears
to provide the advantages of both the horizontal and
vertical design concepts, along with providing the
critical anti-rotational reaction points. This approach
has an advantage over the double horizontal bar
approach by reducing the level of complexity of
docking system-to-interface engagement.
Additionally, the hybrid interface promotes docking
system centering on the wheelchair. The proposed
dimensions are intended to be wheelchair compatible,
and are based upon the previous surveys and data
analysis across varying wheelchair types.
b)
Figure 46 - Hybrid UID concept, example of integration into a
(a) powered wheelchair and (b) a scooter
Figure 45 - Hybrid UID concept and design specification
We conducted preliminary simulations using a
2-D Working Model analysis. The model was not
validated, but was used to obtain a general evaluation
of the crash dynamics and response of the wheelchair
with the hybrid interface. The wheelchair exhibited
a controlled response in these simulations. The next
step was to perform static testing on the hybrid
design. The testing showed that the UID maintained
up to a 10,400-lb load. When failure occurred, it was
at the point where the UID interfaced with the test
jig, which in this case was a press fit into the UID
tubing, resulting in an area of stress concentration.
The final evaluation was a dynamic test that used the
hybrid design to interface an SAE surrogate
wheelchair with a docking system that had been
designed, in part, to prove the feasibility that a
docking system could be designed that would
successfully mate with the hybrid interface design.
The sled test was performed according to the SAE
J2249 specification [SAE, 1996]. The test met J2249
requirements for wheelchair and occupant response
and proved the feasibility of the hybrid UID concept.
Recommended Future Developments
The final step as the RERC funding period came
to a close was to formalize the standard development
process with an independent standard agency. In
Spring1998, a formal request and draft standard was
submitted to ANSI/RESNA Technical Guidelines
Committee to initiate a new work item on the UID
Standard. The new work item has been approved
and work will begin in Spring 1999. The draft
standard must now continue through the standard
development process in the hands of the ANSI/
RESNA working group for the transport wheelchair
(SOWHAT).
66 RERC ON WHEELCHAIR TECHNOLOGY

Publications
Bertocci GE, Karg PE, Hobson DA, Wheeled Mobility
Device Classification System and Database, Technical
Report #6, University of Pittsburgh RERC on Wheelchair
Mobility, Pittsburgh, PA 1996.
Bertocci GE and Karg PE. Wheeled mobility device
database for transportation safety research and standards.
Assistive Technology 1997, 9.2: 102-15.
Hobson DA, Securement of Wheelchairs in Motor Vehicles.
Proceedings of the RESNA ‘95 Annual Conference, RESNA
Press, Washington DC, 1995.
Karg PE, Bertocci GE, Hobson DA. Status of universal
interface design standard for mobility device docking on
vehicles. Proceedings of the RESNA ’98 Annual
Conference, RESNA Press, Washington, DC, 1998.
Karg PE, Bertocci GE, Hobson DA. Universal interface
hardware design standard for mobility device transport
docking systems. Proceedings of the RESNA ’97 Annual
Conference, RESNA Press, Washington DC, 1997: 29-31.
References
Brown PG, QFD: Echoing the voice of the customer, AT&T
Technical Journal, March/April, 1991, pp. 18-32.
Hauser JR, Clausing D The house of quality, The Product
Development Challenge, Harvard Business Review Book,
eds. Kim B. Clark and Steven C. Wheelwright, pp. 299-
315, 1995.
SAE. SAE J2249, Wheelchair tie-downs and occupant
restraints (WTORS) for use in motor vehicles. Society of
Automotive Engineers, Warrendale, PA, 1996.
FINAL REPORT: 1993-1998
67

TASK: T-3 DEVELOPMENT OF DOCKING TYPE
SECUREMENT DEVICES
Investigators: Douglas Hobson, Gina Bertocci, Patricia Karg and Mark McCartney
Students: Linda van Roosmalen, Jonathan EvansCollaborator: Jules Legal
Rationale
The industry standard today for wheelchair
securement in all types of vehicles is the four point
strap-type tiedown device. Although this device
performs adequately under crash conditions when
properly installed and used, it has several major
shortcomings. The main one is that it does not permit
wheelchair users the independent use of transit
vehicles. All belt-type tiedown devices require the
vehicle operator or an attendant to fasten and
unfasten both the wheelchair securement and the
occupant restraint. A self-docking wheelchair
securement device, combined with an “onboard”(integrated)
occupant restraint, offers the
potential to resolve many of the inherent
shortcomings of the existing devices.
Review of the transit accident statistics and crash
severities for large mass transit vehicles {Hobson, et
al. 1997} strongly suggests that the chances of a transit
vehicle occupant experiencing a high “g” crash event
are very small. Therefore, one can take the position,
with a relatively low degree of risk, that a wheelchair
user seated forward–facing in a transit wheelchair
compartment will only experience those “g” loads
associated with normal driving, i.e., maximum
braking, acceleration and rapid turning. Actual
measurements have shown these “g” loads to be less
than 0.65g [Bertocci, et al. 1997]. If this could be shown
to be feasible, it could provide an immediate solution
to improved securement, since the adoption of any
approach using a universal interface drive (UID) is
by necessity a long-term solution.
In order to demonstrate the feasibility of the
proposed universal interface standard detailed in task
T2 [Karg et al. 1997], it was essential to develop and
test actual docking-type securement devices that
could meet the standard. This was done with the
expectation that successful designs would eventually
lead to commercial products.
Another solution for wheelchair containment in
large vehicles is to simply place the occupied
wheelchair rearward facing in a designated station
in the vehicle. The stability of the wheelchair is then
dependent on its brakes, a hand-hold for the
occupant, a padded bulkhead behind the wheelchair
and a vertical stanchion, which prevents the
wheelchair from rotating into the aisle. This study
also looked at the importance of the floor material
selection in optimizing the effectiveness of the brakes
to prevent instability (sliding) towards the rear of the
vehicle when the transit vehicle ascends hills.
Therefore, the multiple approaches taken in task
T-3 were to first develop and test docking devices that
meet two levels of crash severity: a) 30mph, 20g,
frontal crash termed a high “g” crash; and b) loads
associated with normal driving in large vehicles,
termed low “g”. Finally, to explore stability risks
associated with rear-facing compartments as a means
of wheelchair containment, now commonly used in
many European and several Canadian public transit
vehicles.
Goals
1. To design, develop, and demonstrate a high “g”
docking-type securement devices for potential
use in both private and public transport vehicles.
2. To design, develop, and demonstrate a low “g”
docking-type securement devices for potential
use in large public transit vehicles.
3. To explore the sliding stability risks of rear-facing
containment compartments used in public transit
vehicles.
Methods/Results Summary
1) High “g” - crash conditions
The Pitt RERC team took several steps to obtain
the design criteria for the high “g” docking devices.
68 RERC ON WHEELCHAIR TECHNOLOGY

First, the Quality Function Deployment (QFD) tool
was used in two focus group sessions to
systematically seek and prioritize the views of
researchers, transit operators and wheelchair users
of transit vehicles. This information combined with
the ADA requirements for public transit vehicles
established the design goals for the device design.
These criteria were used to develop a conceptual
paper design.
The next step was to establish the crash loads that
the device components would need to withstand
during a 30mph, 20g, frontal crash event. This was
done using a computer simulation model as shown
in Figure 47.
Figure 47 - Frontal Crash Simulation; Wheelchair Secured Using
Proposed Universal Interface Hardware
A partnership was formed with Kinedyne
Corporation, a commercial manufacturer of strap–
type securement devices. This partnership was
successful in securing an $100,000 NIH-STTR grant
that began May 1, 1997. This resulted in the design
and successful sled testing at the University of
Michigan (UMTRI) of a prototype docking device
which utilized the proposed T-2 universal interface
standard (Figure 48). For this sled test, the docking
system and wheelchair interface hardware were used
to secure the surrogate wheelchair which was
developed to evaluate securement system compliance
with the SAE J2249 WTORS standard. Our prototype
docking system met all test requirements established
by the SAE J2249 standard.
To evaluate the ease of maneuverability when
engaging the docking system, actual wheelchair
stations in four types of local transit buses were
measured for replication in our laboratory. The worst
case (smallest) was used to develop a laboratory
mockup of a wheelchair securement station. The
Figure 48 – 20g Frontal Impact Sled Testing of Prototype Docking
System employing Universal Wheelchair Interface Hardware
prototype docking system unit was then installed in
the mockup test station. Wheelchair users were
invited to evaluate maneuverability and ease of
docking.
Based on the results of the above testing, plans
have been made to proceed with a Phase II, NIH-
STTR proposal in an effort to further refine and
commercialize the docking system.
2) Low “g” Docking Device
In summary, the focus of this aspect of the task
was to develop a user-activated wheelchair
containment device for use in large transit vehicles
that would readily secure any wheelchair entering
the vehicle. Again, the QFD process and focus groups
were used to arrive at the design criteria. Two
generations of prototype devices were constructed
and tested in the laboratory and with wheelchair
users. A goal of 1 g was established as the minimum
load that the device must withstand when securing a
variety of different wheelchairs, both manual and
powered. This would provide a margin of
approximately 0.35g above the maximum loads
actually measured (0.65g) during normal driving
maneuvers. Static pull tests were used to simulate
the securement loading by an occupied wheelchair
under maximum normal driving conditions. The
static pull tests were applied in the frontal direction
until the wheelchair released or substantially moved
within the containment device (Figures 49-51).
FINAL REPORT: 1993-1998
69

wheelchair creating two modes of restraint – friction
and mechanical interlocking. Both air pressures (plate
drive, cylinders and bellows) are adjustable so
possible wheelchair damage to wheelchairs can be
minimized. The prototype securement device, if
successful, would ultimately be designed to fit within
the geometry of a standard bus seat.
Figure 49 - Close-up of the low “g” Docking System Prototype
Figure 51 – Pull testing set up of the low “g” prototype
securement device
Test Procedure
Figure 50 – Low “g” Docking System Securing Power
Wheelchair
Docking Device Operation
The prototype consists of two horizontally
adjustable plates that have inflatable bellows built
into the plates. After backing the wheelchair into the
securement device, the user flips an accessible switch,
which activates two pneumatic cylinders that move
the plates towards the wheelchair chair. The plate
drive mechanism is self-centering so it can
compensate for misalignment of the wheelchair in the
docking station. Once the plates contact the
wheelchair, the bellows inflate into the cavities of the
Eight manual and powered wheelchairs were
obtained for testing. The geometry and weight of
the chairs were recorded. A person that approximated
a 50 th percentile male mass distribution was used as
the occupant. Several measurements were taken on
each wheelchair including the position of the rear
wheels and into which cavities the bellows inflated.
The wheelchair was then placed in the docking
system with the brakes engaged. The setup includes
a platform to which the docking system is fixed. A
winch with a 4000 lbs. capacity was fixed to the base
of the platform in order to apply a horizontal static
load at the combined height of the wheelchair and
users center of gravities. The docking system was
then engaged. Plate pressure, bellows pressure,
which bellows contacted the wheelchair and the
nature of the contact (friction or mechanical
interlocking), was recorded. The test involved
applying a static load to the wheelchair in 40-pound
increments, measuring the horizontal displacement
of the wheelchair after each increment.
70 RERC ON WHEELCHAIR TECHNOLOGY

Results of Low G Tests
The following graphs summarize the second set
of pull tests that were done, after a modification to
prototype was done, based on the results of first pull
test. The graph in figure 52 shows the load and
horizontal displacement profiles for the eight
wheelchairs tested three manuals and five powered.
It clearly shows that two E&J manual wheelchairs had
the largest displacements 12.8 and 13.2 ins, before
breaking free of the securement device. The
breakaway loads were 360 and 320lbs, respectively.
The graph in figure 53 shows the comparative
static loads converted to equivalent “g” loads. As can
be seen, most wheelchairs, except for the E&J Premier
and Quickie 2, both manual wheelchairs, either
closely approached or exceeded the 1 “g” design goal.
It was determined that the grasp on the large wheels
of the manual wheelchair was not as effective in
restraining the wheelchair as was the engagement
with the smaller wheels typical of the powered
wheelchairs tested. Plans have been formulated to
address this problem in a future design.
Test 2
14
12
E&J Manual b
E&J Manual a
10
8
6
E&J Tempest a
4
Quickie2
Action Arrow a
Action Arrow b
2
E&J Premier
E&J tempest
0
0 50 100 150 200 250 300 350 400 450 500
Load (lbs)
Figure 52 – Results of low “g” testing: wheelchair displacement vs. applied load
Test 2
G's Until Release
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
E&J Manual a
E&J Manual b
Action Arrow b
E&J Tempest b
E&J tempest a Action Arrow a
Quickie2
E&J Premier
1 2 3 4 5 6 7 8
Chair
Figure 53 – Low “g” testing: “g” values vs. wheelchair types
FINAL REPORT: 1993-1998
71

3) Sliding Stability Tests of Rearward Racing
Wheelchairs
Background
Wheelchairs and their occupants transported on
large vehicles in European countries are often secured
using a compartment approach. Similar methods are
currently under consideration in Canada for use in
large transit vehicles traveling at low speeds and
having low incidence of frontal crash [Shaw, 1997].
Compartmentalization consists of a rear facing
wheelchair positioned in front of a padded bulkhead,
which is used as back restraint. A vertical stanchion
is aligned with the aisle to prevent rotation of the
wheelchair into the aisle and to provide a hand-hold
for occupants. Under such conditions, the ability of
the wheelchair to stay in place without slipping
during normal driving maneuvers is critical to the
safety and security of the occupant and other
passengers.
In the US, wheelchair stations on public transit
vehicles are typically equipped with four tiedown
straps to secure the wheelchair. However, due to
inconveniences, it is not uncommon to find a high
level of disuse of these wheelchair tiedown systems.
Under these conditions, wheelchair slippage also
becomes a concern during normal driving. Since
wheelchair slippage is dependent upon the friction
between the wheelchair tires and vehicle flooring, it
is of interest to evaluate the effects of various flooring
surfaces on wheelchair slippage. (Note: The authors
do not advocate traveling without wheelchair
securement and recommend the use of four tiedowns
and occupant restraints under all conditions.)
Figure 54 - Sliding test procedure using tilt platform
Figure 55a - Smooth surface
Goal
The goal of this study was to evaluate the
influence of floor surface materials on wheelchair
slippage under conditions simulating normal driving
maneuvers and typical road terrain.
Method
This study utilized a tilt platform, shown in Figure
54, to simulate conditions of normal driving.
Figure 55b - Fluted surfaceFigure
72 RERC ON WHEELCHAIR TECHNOLOGY

55c - Round dimpled surface
mounted to the platform to monitor the tilt angle. A
tape marker was placed on the rear wheel to aid in
detecting initial sliding.
With an ATD occupied wheelchair placed upon
the flooring sample, the platform was raised from 0
degrees. Tilt platform angle was monitored and
recorded as the wheelchair began to slide. This
process was repeated for each flooring surface using
each of the wheelchair types. Three trials of each
wheelchair-flooring combination were conducted to
verify repeatability. The fluted flooring surface was
evaluated in two configurations; with fluting parallel
and fluting perpendicular to direction of travel.
Figure 55d – Silicagrit surface
Four different types of vehicle flooring materials,
shown in Figures 55a-d, were mounted to the tilt
platform. A 75th percentile (220 lb) male
anthropomorphic test device (ATD) was seated in
each of four wheelchair types, which were placed on
each of the four flooring surfaces. Wheelchair types
included a conventional manual wheelchair (22 lb),
a sports manual wheelchair (18 lb), a powerbase (189
lb), and a conventional power wheelchair (135 lb).
The wheelchair and ATD were positioned so as to
simulate a rear facing orientation in a vehicle.
Wheelchair brakes were locked and the ATD was
restrained using a pelvic belt. To replicate the
compartmentalization approach and securement
system disuse, no wheelchair securement was used
during testing. Test conditions simulated a vehicle
ascending a hill and vehicle acceleration. These
conditions consist of a road grade near 20% or an 11.5
degree slope, and an acceleration of 0.2g [Adams,
1995 and City of Pittsburgh Public Works, 1997]. To
simulate these conditions, the tilt platform was
designed to rotated from 0 to 45 degrees, where sin
[tilt angle] is equal to equivalent acceleration
expressed in “g’s”. The rate of platform incline was
constant at 1.25 degrees/sec. An inclinometer was
FINAL REPORT: 1993-1998
73
Results
The average sliding angle of three trials was
calculated for each wheelchair positioned on each of
the five flooring surface conditions. Figure 56
indicates the angle at which sliding began for each of
the evaluated wheelchairs using each of the floor
surfaces. Performance can be compared to the
steepest terrain encountered or 20% in the Pittsburgh
area.
Sliding Angle (degrees)
24.0
22.0
20.0
18.0
16.0
14.0
12.0
10.0
8.0
Round Raised Dimples
Silica Grit Surface
Fluted-Grooves Parallel
Fluted-Grooves Perpendicular
Smooth Surface
Max Road Grade 20% or 11.3 deg
6.0
Conv Manual Sport Powerbase Conv Power
WMD Type
Notes:
1. All tests conducted using 75th %tile male
ATD seated in WMD.
2. Rate of tilt platform rise=1.25 deg/sec
3. Tests conducted using dry surface.
Figure 56 - Sliding angles vs WMD type for various surfaces

The same test data is presented (Figure 57) in
terms of “equivalent acceleration” through the
conversion sin [platform tilt angle] = equivalent
acceleration. In this form, results can be compared to
the level of acceleration experienced during vehicle
acceleration, or 0.2g.
Results show that the silica grit surface provided
the greatest resistance to wheelchair slippage for all
evaluated wheelchairs. The silica grit surface and the
fluted surface installed with fluting perpendicular to
travel direction, prevented wheelchair slippage under
conditions of normal acceleration (0.2g) and
ascending maximum city street grades (20%). Other
evaluated flooring surfaces would be questionable
in their ability to prevent wheelchair sliding under
these conditions.
Discussion
The resistance to sliding is influenced by the
friction force generated between the wheels and the
floor surface. The magnitude of the friction force is
directly related to the weight of the occupied
wheelchair and the coefficient of friction between the
floor surface and the tires. Clearly the increased
weight associated with the powerbase testing
improved resistance to sliding when using the silica
grit or fluted-perpendicular surfaces.
These tests were conducted under controlled
laboratory conditions. Any road surface irregularities
transmitted to the wheel/floor interface or wet
surfaces, are most likely to promote sliding at
inclinations less than those determined under
laboratory test conditions.
Conclusions
Equivalent "g"
0.35
0.30
0.25
0.20
0.15
0.10
Round Raised Dimples
Silica Grit Surface
Fluted-Grooves Parallel
Fluted-Grooves Perpendicular
Smooth Surface
Max Acceleration/Braking 0.2g
Conv Manual Sport Powerbase Conv Power
WMD Type
Notes:
1. All tests conducted using 75th %tile male
ATD seated in WMD.
2. Rate of tilt platform rise=1.25 deg/sec
3. Tests conducted using dry surface.
Figure 57 - Equivalent “g” sliding point vs WMD type for various
surfaces
The results from the tests show that differences
in wheelchair slippage can be expected across
different flooring surfaces. Vehicle manufacturers can
decrease the risk of slippage through careful selection
of flooring surfaces. Wheelchair securement stations
and compartments should be constructed using only
those flooring surfaces, such as silica grit, which
reduce wheelchair slippage.
Outcomes Summary
The key outcomes of task T-3 may be summarized
as follows.
a) Development Activities
• The successful feasibility design, development,
testing and demonstration of a high “g”, universal
interface-compatible docking system working in
collaboration with an industry partner (STTR-
Phase I/Kinedyne Corp.) and local transit
authorities. Plans call for the continued transfer
of this development upon successful acquisition
of Phase II STTR support.
• The successful feasibility design, development
and testing of low “g” docking system. This
development is now ready for design refinements,
followed by identification of an industry partner
and the formal initiation of the technology
74 RERC ON WHEELCHAIR TECHNOLOGY

transfer phase. We will welcome any partners
who wish to join our efforts to move this
development forward.
b) Education activities
In total, seven instructional courses have been
held related to wheelchair transportation safety.
These courses have been well received and have
stimulated the plan to produce both video and
WWW-based instructional materials. These courses
are:
• Preconference instructional course entitled
“Wheelchair Transportation Safety”, the
International Seating Symposium, Pittsburgh, PA,
January 22, 1997.
• Preconference instructional course entitled
“Wheelchair Transportation Safety”, RESNA
Annual Conference, Pittsburgh, PA, June 20, 1997.
• Preconference instructional course, International
Seating Symposium, Vancouver, BC, “Wheelchair
Transportation Safety”, February 26-28, 1998.
• Overview of ANSI/RESNA wheelchair
standards. Assistive Technology Training
Program for Rehabilitation Technology Suppliers,
University of Pittsburgh, Pittsburgh, PA, February
6-7, 1998.
• Keynote speaker at Medtrade ’98, “Issues and
Standards on Transporting People Who Use
Wheelchairs in Motor Vehicles”, Atlanta, GA,
November 1998.
Recommendations for Future Developments
Future efforts will focus on the refinement of the
high “g” and low “g” docking systems designs in
cooperation with industry partners. Funding for this
effort will be pursued through a Phase II STTR or
SBIR grants. Phase I activities will allow further
feasibility analysis of the both concepts from both the
user and the transit application perspectives. No
further work is anticipated on the sliding stability of
rearward facing securement compartments.
Publications
Hobson DA, Bertocci GE, Bernard R, McCartney M,
Wheelchair Transit Safety; A Conceptual Case for Low ‘g’
Securement Approach. Proceedings of the RESNA ’97 Annual
Conference, Pittsburgh, PA, June 1997.
Bertocci, GE, Digges, K, Hobson, DA. The Affects of
Wheelchair Securement Point Location on Occupant Injury
Risk, Proceedings of the RESNA ’97 Annual Conference,
Pittsburgh, PA June 1997.
Karg, P, Bertocci, GE, Hobson, DA. Universal Interface
Hardware Design Standard for Mobility Device Transport
Docking Systems, Proceedings of the RESNA ’97 Annual
Conference, Pittsburgh, PA, June 1997.
Bertocci, G, Hobson, DA, McCartney, M, Rentschler, A. The
effects of various vehicle floor surfaces on wheelchair
sliding under normal driving conditions. Proceedings 21st
Annual RESNA Conference, Minneapolis, MN, June 1998.
References
Shaw, G. “The Need to Establish Appropriate Levels of
Crash Protection for Wheelchair Riders in Public Transit
Vehicles,” Proceedings - RESNA ‘97 Annual Conference,
1997.
Personal Communication with City of Pittsburgh Public
Works, Jan, 1997.
Adams, T. “Wheelchair Stability Testing,” SAE WTORS
Meeting, Dearborn, MI, 1995.
Brown PG, QFD: Echoing the voice of the customer, AT&T
Technical Journal, March/April, 1991, pp. 18-32.
Hauser JR, Clausing D The house of quality, The Product
Development Challenge, Harvard Business Review Book,
eds. Kim B. Clark and Steven C. Wheelwright, pp. 299-
315, 1995.
FINAL REPORT: 1993-1998
75

TASK: T-4 RESEARCH AND COORDINATION RELATED TO
STANDARDS DEVELOPMENT FOR WHEELCHAIR
TRANSPORTATION TECHNOLOGY
Investigators: Douglas Hobson, Gina Bertocci, Kennerly Digges, and Patricia Karg
Rationale
In 1993, there were no voluntary industry
standards for wheelchair securement devices or for
wheelchairs used as seats in motor vehicles. Through
the adoption of voluntary wheelchair transportation
standards by the involved industries, the safety of
those using wheelchairs as seats in motor vehicles
will begin to approach that of non-disabled persons
using OEM vehicle seats. This task has been
committed to improving the safety and convenience
of wheelchair transport through facilitating the
development and adoption of voluntary industry
standards on a worldwide scale.
Goals
1. Provide research and administrative support in
the development of voluntary product
performance standards that will ultimately
facilitate the safe transport of those using
wheelchairs as vehicle seats, and
2. Facilitate the implementation of the standards
throughout the user and service provider
communities.
Outcomes Summary
The RERC on Wheeled Mobility has provided
working group leadership and research support
towards the following standards development:
• The Society of Automotive Engineers (SAE) J2249
Wheelchair Tiedown and Occupant Restraints
Systems (WTORS) for Motor Vehicles standard
has been adopted as a recommended practice
(completed January 1997). This standard serves
as a benchmark for design and testing of four
point strap-type wheelchair securement systems.
A companion applications guideline for J2249 is
due for completion in January 1999 (revised draft
in process).
• SAE J2252, provides the details on the design
and construction of the surrogate wheelchair
used in the testing of WTORS to the J2249
standard.
• The ANSI/RESNA Subcommittee on
Wheelchairs and Transportation (SOWHAT) has
completed the transportable wheelchair
standard (ANSI/RESNA WC-19). A
collaborative research effort between the
University of Pittsburgh, University of Michigan
and University of Virginia has led this effort with
support from private and federal sources. A
draft companion document describing the
rationale for transport wheelchair standards is
currently under development. This document
will provide wheelchair users, care givers,
transporters and manufacturers with practical
guidance on the use of the standard. It will be
available for general distribution in spring 1999.
• A parallel WTORS standard’s effort (ISO 10542,
parts 1&2), conducted under the auspices of
International Standards Organization (ISO), has
been under way since 1985. The effort on parts
1&2 (general requirements and requirements for
strap-type WTORS) is now proceeding to the
final stages of international approval and is due
for completion in 1999. Due to collaborative
efforts by the RERC and others, this standard
has been closely harmonized with the U.S.
recommended practice document, WTORS-SAE
J2249.
• ISO 7176/WC-19, Wheelchairs Used as Seats in
Motor Vehicles standard, which parallels ANSI/
RESNA WC-19, is also moving forward at the
ISO level. This standard is scheduled for
completion in spring 2000.
76 RERC ON WHEELCHAIR TECHNOLOGY

• The progress, current status (meeting minutes),
and most recent working group versions of the
above standards and companion documents can
be viewed and downloaded from the RERC’s
WWW site (http://www.rerc.upmc.edu/).
Publications
Hobson DA, Wheelchair Transport Standards; What Are
They All About, Proceedings of the RESNA ’96 Annual
Conference, Salt Lake City, UT, June 1996.
Hobson, DA, Wheelchair Transit: An Unresolved
Challenge in a Maturing Technology. Guest Editorial, J
Rehabil Res Dev, 34(2), April 1997.
Schneider L., Hobson D.A. SAE J2249—WTORS
Schneider L, Hobson D., Bertocci G.—SAE J2249 WTORS
companion document
Schneider L., Hobson D. ANSI/RESNA WC-19
Shaw G., Schneider, L, Bertocci, G, Hobson D. WC-19
Companion
Hobson D., Schneider L, ISO 7176/19
FINAL REPORT: 1993-1998
77

IV. TRAINING AND DEMONSTRATION ACTIVITES
Responsible Staff:
Overview
Elaine Trefler, RERC Faculty
Training and demonstration activities are an
important aspect of any RERC’s mission. This activity
at the University of Pittsburgh RERC embodies both
formal and continuing education for rehabilitation
professionals, as well as providing learning
experiences for users of assistive technology. This
aspect of the Center’s program can be subdivided into
four inter-related activities: graduate education,
research training, continuing education, and
consumer training. Support for student training came
from several NIDRR training grants plus the
Graduate Student Researcher (GSR) support
provided directly by the NIDRR-RERC grant.
TR-1 GRADUATE EDUCATION
The RERC contributes to the Department of
Rehabilitation Science and Technology’s graduate
level education program by providing an
environment where students gain research and
development experiences. The RERC dedicated
laboratories were regularly used for classroom
demonstrations and other activities in which students
are exposed to the practice of research aimed at
improving wheelchair technology. For example,
equipment and experimental test setups for RERC
projects are presented as examples of research
activities in the course entitled “Fundamentals of
Rehabilitation Engineering.” Information resources,
developed with support by the RERC, also
contributes to the graduate education program by
making available a convenient and comprehensive
source of reference information related to assistive
technology. Further information on the RST
Department, the faculty, research activities and degree
course offerings can be reviewed on the RST WWW
site: http://www.RST.UPMC.edu.
TR-2 RESEARCH TRAINING
The RERC-supported faculty have served as
research advisors for 17 graduate students working
on RERC tasks. The table on page 73 is a list of these
students, the task(s) worked on, and responsible
faculty advisors.
The RERC also provided advanced student
degree thesis experiences for four students from
Dalarna University, Borlange, Sweden.
TR-3 CONTINUING EDUCATION
Post-service education for practicing
professionals and interested consumers is the third
forum used to provide educational and training
experiences in assistive technology. Participation in
workshops and seminars is an effective way to share
information with others. The following is a summary
of five-year training activities.
Bertocci GE, Special Needs in Student Transportation, State
College, PA, June 1996.
Bertocci GE and Hobson, DA, Special Needs in Student
Transportation. International Seating Symposium -
Vancouver, BC, March 1996.
Bertocci GE. “Special Needs in Student Transportation”,
Pupil Transportation Association of Pa. - 25th Anniversary
Conference, State College, PA, June 1996.
Brienza, D.M. RESNA Annual Conference, Session Chair,
“Seating and Positioning Technology.” Salt Lake City, Utah,
June 1996.
Brienza D.M., Schuch J, and Sprigle S. “Wheelchair Seating
and Positioning: Improving Your Services from Assessment
through Follow up.” University of Virginia,
Charlottesville, VA, September 22 and 23, 1995. Continuing
Education Workshop.
Cooper, RA, Approach to rehabilitation, Ankara Numune
Hospital & University of Pittsburgh Medical Center 1st
Joint Symposium, Ankara, Turkey, May 1997
78 RERC ON WHEELCHAIR TECHNOLOGY

Student Degree Program Tasks Faculty Advisor
Preetam Alva, BS, MS ME Ph.D. ME PM1, PM6 Hobson
Thomas Ault, BS Computer Eng. Ph.D. CS S2 Brienza
Randy Bernard, BS, MS Ind. Design Ph.D. SHRS PM6 Hobson
Gina Bertocci, MS Ph.D. Bioeng. T1-4 Hobson
Dalthea Brown, MS Physical Therapy Ph.D. SHRS S4, S5 Trefler
Jonathan Evans, Undergraduate B.S. M.E. PM1, PM 6 Hobson
Jess Gonzalez, BS M.S. Bioeng. STD1 Cooper
Thomas O’Connor, B.S. Ph.D. SHRS STD1 Cooper
Khondukar Mostafa, BS EE M.S. EE PM1b, S3 Brienza
Wonchul Nho, BS, MS EE Ph.D. EE PM1c, PM3, S1, S3 Brienza
James Protho, BS CS M.S. RST PM3, S1 Brienza
Heather Rushmore, BS Speech Path. M.S. RST WP1 Trefler
Tracy Saur, BS Occupational Therapy M.S. OT S4 Boninger
Jue Wang, BS EE, MS Bioeng. Ph.D. RST S1, S2 Brienza
Linda Van Roosmalen Ph.D. SHRS T-2, T-3, PM-6 Hobson
Tom Bursick MSc. RST S-6 Trefler
Bert Joseph MSc. RST S-6 Trefler
Cooper, RA, Sports fitness equipment for people with
disabilities, Sports & Fitness for Individuals with
Disabilities, Springfield College, Springfield, MA, May
1997
Hobson, D.A. and Bertocci, GE. Wheelchair Transportation
Industry Update, RESNA, 1996 Mid Atlantic Regional
Planning Committee Conference, Philadelphia, PA,
November 16, 1996.
Hobson, D.A. Overview of Activities in the Rehabilitation
Engineering Program, Disability Awareness Days,
Pittsburgh, PA, October 4, 1996.
Hobson, DA, Bertocci, G, Karg, PE. “Wheelchair
Transportation Safety Workshop”, Transporting Students
with Disabilities Conference, March 5-6, 1996,
Birmingham, AL.
Hobson, DA, Bertocci, G. “Factors Influencing Wheelchair
Transportation Safety”, Vancouver International Seating
Symposium, March 1996.
Hobson DA , Bertocci GE, and Karg PE, Transportation
Forum: Factors Influencing Wheelchair and Occupant
Crash Response. (Invited forum raising current issues).
Conference on Transporting Students with Disabilities:
Birmingham, AL, March 1996.
Hobson, D.A. Dundee ‘97 International Conference on
Wheelchairs and Seating, Invited Lecturer, Dundee,
Scotland, September 8 - 12, 1997.
Hobson, D.A. and Bertocci, G. Wheelchair Transportation
Safety Workshop, RESNA Conference, Pittsburgh, PA, June
20, 1997.
FINAL REPORT: 1993-1998
79

Hobson, D.A. and Bertocci, G.E. Transporting Students
with Disabilities: Wheelchair Safety, Education Service
Center, Houston, TX, February 21, 1997.
Hobson, D.A. Wheelchair Standards, Assistive Technology
Training Program, University of Pittsburgh, Pittsburgh, PA,
March 13-15, 1977.
Hobson, D.A., Bertocci, G.E. and Karg, P.E. Wheelchair
Transportation Safety Seating Symposium Preconference
Workshop, ISS, Pittsburgh, PA, January 22, 1997.
Hobson, D.A. Overview of ANSI/RESNA wheelchair
standards. Assistive Technology Training Program for
Rehabilitation Technology Suppliers and Others.
University of Pittsburgh, Pittsburgh, PA, February 6-7,
1998.
Hobson, D.A, Bertocci, G. Wheelchair transportation
safety. 14th International Seating Symposium, Vancouver,
BC, February 26-28, 1998.
Hobson, D.A. Presenter, American Society on Aging 44th
Annual Meeting, San Francisco, CA. March 25-28, 1998,
Hobson, D.A., “Issues and Standards on Transporting
People Who Use Wheelchairs in Motor Vehicles”, keynote
speaker, Medtrade ‘98, Atlanta, GA November 1998.
Letechipia, J and Pelleschi T, “Implementation of a
Comprehensive Assistive Technology Service Delivery
Program as a Hub of a Regional Network of AT Services.”
RESNA 19th Annual Conference, Salt Lake City, UT, June
1996.
Karg, P. “Update on Wheelchair Transportation
Standards”, Breakout Session-5th National Conference and
Exhibition on Transporting Students with Disabilities,
Birmingham, AL, March 1996.
Karg, P. Session Chair, “Wheelchair and Seating
Biomechanics”, RESNA 19th Annual Conference, Salt Lake
City, UT, June 1996.
Karg, P., Bertocci, G., “Wheelchair Transportation Safety
Standards Update and Factors Influencing Wheelchair
Transportation Safety”, Pittsburgh Assistive Technology
Association (PATA) Meeting, February 1996.
Karg PE and Bertocci GE, Wheelchair Transportation Safety
Workshop and Breakout Session, Pittsburgh Assistive
Technology Association (PATA) Meeting, Feb. 1996.
Schmeler, M.R. “Powered Mobility: Alternative and
integrated controls.” NYSOYA Annual Conference,
Fishkill, NY, October 1995.
Schmeler, M.R. “Reasonable accommodations: Providing
assistive technology assessments and interventions in the
workplace.” Westchester Consortium of Vocational
Counselors, White Plains, NY, September 1995.
Schmeler, M.R. Wheelchair seating and mobility. Beverly
Health Systems rehabilitation managers. Spokane, WA.
October 1996.
Schmeler, M.R. “Strategies for powered mobility evaluation
and readiness training.” AOTA 76th Annual Conference,
Chicago, IL, April 1966.
Schmeler, M.R., “Positions for Function: Seating and
workstations in the classroom.” RESNA 19th Annual
Conference, Salt Lake City, UT, June 1996.
Schmeler, M.R., Brienza, D. and Shapcott, N. Wheelchair
seating: Seat cushion selection. RESNA Mid-Atlantic
Regional Conference, Philadelphia, PA November 1996.
Schmeler, M.R., Shapcott, N. Pelleschi, T. and Dugan, J.
Assistive Technology Service Delivery. Mt. Aloysius
College OT/PT faculty. Cresson, PA. August 1996
Schmeler, M.R. and Boninger, M.L. Appropriate setup
and prescription of wheelchairs. Shoulder Pain in
Wheelchair Users: Prevention, Assessment and Treatment
Conference, Pittsburgh, PA, May 1997.
Schmeler, M.R. et al. Introduction to wheelchair seating
and mobility. Preconference workshop, ISS, Pittsburgh, PA
January 1997.
Schmeler, M.R. Wheelchair seating and mobility in longterm
care facilities. Vencor, Inc. therapists and rehabilitation
managers, Clarkston, WA, May 1997.
Schmeler, M.R. et al. Rehabilitation Technology Supplier
Modular Training Course. University of Pittsburgh,
Pittsburgh, PA. March 1997.
Schmeler, M.R., Angelo, J.A., Doster, S., Larson, B., Ellexson,
M. and Armstrong, F. Assistive Technology as a reasonable
accommodation. AOTA 77th Annual Conference, Orlando,
FL, April 1997.
80 RERC ON WHEELCHAIR TECHNOLOGY

Schmeler, M.R., Shapcott, N. Dugan, J. Petersen, B.,
Pelleschi, T. Sanna J. and Lego, F. Strategies for providing
model assistive technology services within vocational
rehabilitation. RESNA Annual Conference, Pittsburgh, PA
June 1997
Trefler E and faculty, Training Program for Rehabilitation
Technology Suppliers, Home Study and Distance
Education Program, 1994-98
Trefler E and faculty, Wheelchair Seating and Positioning,
Review Course for Rehabilitation Technology Suppliers
(RTS) preparing for the RESNA Generalist Exam, Reno,
Nov, June 1995
Trefler, E. “Single Subject Research: A Research Method
for Seating and Mobility Clinicians. “Comparison of
Anterior Trunk Supports for Children with Cerebral Palsy.”
The Canadian Seating and Mobility Conference, Toronto,
Canada, Sept 1995.
Trefler, E. and Angelo, J. “Surveying Users of Integrated
Controls - A Pilot Study.” Proceedings, ARATA pp. 17-19.
Adelaide, Australia, Oct 1995.
Trefler, E. “Single Subject Research: A Research Method
for Seating and Mobility Clinicians. “Comparison of
Anterior Trunk Supports for Children with Cerebral Palsy.”
ARATA Conference, Adelaide, Australia. Oct 1995.
Trefler, E., “The Use of Integrated Controls: Comparison
of Anterior Trunk Supports for Children with Cerebral
Palsy”. ISS 12th Annual Conference, Vancouver, BC, Feb
1996.
Regarding major conference activities, the
International Seating Symposium was hosted in
Pittsburgh in 1995 and 1997, with co-sponsorship in
Vancouver Canada in 1994, 1996 and 1998. Over 800
practicing professionals, suppliers, manufacturers
and consumers attended annually in Pittsburgh. This
is possibly the most important annual educational
event in wheelchair technology. The RERC staff took
advantage of the opportunity to organize and copresent
a series of pre-conference workshops on:
wheelchair transportation safety, beginner level
seating and a review course for Rehabilitation
Technology Suppliers.
RESNA ’97 was also held in Pittsburgh June 20-
24. This provided a unique opportunity to share
information with a larger audience and to invite
interested researchers, students and wheelchair users
to tour our research facilities and discuss common
interests.
As part of the dissemination and education
program of the RERC and the RST, a distance
education program for Rehabilitation Technology
Suppliers (RTS) was developed. Along with reading
materials and videotape demonstrations, students are
being provided with an entry-level training program
in assistive technology. Wheelchair suppliers are the
primary audience because in the changing health care
market consumers sometimes choose to go directly
to suppliers for wheelchair technology. In order to
ensure a minimal level of expertise, the suppliers
organization, The National Registry of Rehabilitation
Technology Suppliers (NRRTS), endorsed the
University of Pittsburgh in the development of this
program. NRRTS encourages RTSs to take the
certification exam offered by the Rehabilitation
Engineering and Assistive Technology Society of
North America (RESNA).
TR-4 CONSUMER TRAINING
Consumer education has been an ongoing part
of many RERC events, such as those indicated above.
Wheelchair user education also occurred as a natural
component of the focus group meetings that were
held fin conjucntion with Tasks PM3, PM6, T1, T2 and
T3. This direct involvement created opportunities for
consumers to learn more about the research process
and wheelchair and seating technology. For several
years the RERC was a co-sponsor of the local Assistive
Technology Tech Fair which created unique
opportunities for consumer participation and
learning experiences. And finally, the RERC
sponsored consumers and guest speakers to attend
the annual SHOUT/Pittsburgh Employment
Conference that features the creation of employment
opportunities for persons using augmented
communication.
FINAL REPORT: 1993-1998
81

V. DISSEMINATION AND UTILIZATION
Responsible Staff: Douglas Hobson, Elaine
Trefler, Jean Webb, Ashli Molinero, Patricia Karg and
Task Leaders
Goals
1. To disseminate the results of RERC activities
2. To serve as an information resource on wheelchair
technology
Approach
Information on wheeled mobility technology was
disseminated to consumers, manufacturers and
professionals. The planned content and target groups
for dissemination and utilization activities are
summarized in the diagram below.
Outcomes Summary
The information dissemination and utilization
activities continued throughout the five years of the
RERC on Wheeled Mobility. These took the form of:
peer reviewed journal publications (25); extended
abstracts in conference proceeding papers (66);
books/chapters (7); technical reports (6);
presentations at local, national and international
meetings (24); and formally organized instructional
courses or workshops (7). A complete reference listing
of the above dissemination activities follows.
Utilization of many of these activities was facilitated
by workshops, focus groups, conferences and direct
communication with industry representatives.
In 1995, the RERC also launched its WWW pages as
Dissemination and Utilization Plan
REC on Technology
Evaluation &
Transfer
Consumers
Manufacturers
Professionals
technology fair
magazine articles
pamphlets
consumer newsletter
public media
workshops
videotapes - general
drawings
design specifications
prototypes
needs analysis
clinical trial results
workshops
technology fair
inservice education
educational materials
publications
videotapes - training
symposium
Figure 58 - Dissemination plan focusing on three primary groups
82 RERC ON WHEELCHAIR TECHNOLOGY

an extension of its dissemination activities. Research
activities, status reports, publication listings,
downloadable technical reports and standards
documents, and contact information were all made
available via the RERC’s site. Requests for
information on varied aspects of wheelchair
technology came to the RERC almost daily. Students,
researchers, consumers and clinicians all contacted
members of the RERC team for information.
Electronic communications, such as faxes, emails and
the RERC’s WWW site postings, all facilitated timely
responses to the majority of these requests.
Dissemination Listings:
Publications/Workshops/Grants/Patents and
Awards
Peer Reviewed
Angelo J and Trefler E A survey of persons who use
integrated control devices, Asst Technol, 1998;10:77-83
Angelo, JA, Buning, ME, Schmeler, MR and Doster, S.
Identifying best practices in the occupational therapy
assistive technology evaluation: An analysis of three focus
groups. American Journal of Occupational Therapy Accepted
and pending publication 1997
Bertocci GE, Digges K, Hobson DA Shoulder Belt Anchor
Location Influences on Wheelchair Occupant Crash
Protection. Journal of Rehab Research and Devel July 1996;
33(3): 279-289.
Bertocci, GE, Digges, K, Hobson, D. Development of
Transportable Wheelchair Design Criteria Using Computer
Crash Simulation. IEEE Transactions on Rehabilitation
Engineering, Vol 4, No 3, Sept. 1996: 171-181.
Bertocci, GE, Digges, K, Hobson, DA. Shoulder Belt
Anchor Location Influences on Wheelchair Occupant
Crash Protection. Journal of Rehab Research and Devel, Vol
33, No 3, July 1996:279-289.
Bertocci, GE, Karg, PE, Hobson, DA. Wheeled mobility
device database for transportation safety research
standards. Assistive Technology, pp. 102-115, Vol. 9.2, 1997
Boninger ML, Saur T, Trefler E, Hobson DA, Burdette R,
and Cooper RA: Postural Changes with Aging in
Tetraplegia, Archives of Physical Medicine and Rehabilitation,
Vol. 79, No. 12, pp. 1577-1581, December 1998.
Brienza D.M. and Angelo J. A Force Feedback Joystick
and Control Algorithm for Wheelchair Obstacle Avoidance.
Disability and Rehabilitation Mar 1996; 18(3): 123-129.
Brienza DM, Angelo J, Henry K. Consumer Participation
in Identifying Research and Development Priorities for
Power Wheelchair Input Devices and Controllers. Assistive
Technology July 1995; 7.1:55-62.
Brienza DM, Chung K-C, Brubaker CE, Wang J, Karg TE
A System for the Analysis of Seat Support Surfaces Using
Surface Shape Control and Simultaneous Measurement of
Applied Pressures. IEEE Transactions on Rehabilitation
Engineering June 1996; 4(2): 103-113.
Brienza, D.M., Chung, KC, Brubaker, CE, Wang, Jand Karg,
PE. A System for the Analysis of Seat Support Surfaces
Using Surface Shape Control and Simultaneous
Measurement of Applied Pressures, IEEE Transactions on
Rehabilitation Engineering, Vol. 4, No. 2, pp. 63-67, 1996.
Brienza, DM and Karg, PE. Optimization of seat support
surface shape using interface pressure and soft tissue
stiffness: A comparison of interface characteristics for spinal
cord injured and elderly patients. Archives of Physical Med
and Rehabil accepted, pending publication 1997
Brienza, DM, Cooper, RA, Brubaker, CE. Wheelchairs and
seating. Current Opinion in Orthopaedics 1996:7 (vi)
Brienza, DM, Chung, KC, Brubaker, CE, Wang, J, Karg, PE
and Lin, CT. A system for the analysis of seat support
surfaces using surface shape control and simultaneous
measurement of applied pressures. IEEE Transactions on
Rehabilitation Engineering 1996 4(2) pp.103-113
Brienza, DM, Karg, PE and Brubaker, CE. Seat cushion
design for elderly wheelchair users based on minimization
of soft tissue deformation using stiffness and pressure
measurements. IEEE Transactions on Rehabilitation
Engineering, 1996 4(4) pp 320-328
Cooper R, Trefler E, Hobson DA. Wheelchairs and Seating:
Issues and Practices. Technology and Disability 1996; 5(1): 3-
16.
Cooper RA. Forging a New Future: A Call for Integrating
People with Disabilities into Rehabilitation Engineering.
Technology and Disability 1995; 4: 81-85.
Cooper RA. Intelligent Control of Power Wheelchairs. IEEE
Engineering in Medicine and Biology Magazine 1995; 15(4): 423-
431.
FINAL REPORT: 1993-1998
83

Cooper, R.A., A Perspective on the Ultralight Wheelchair
Revolution, Technology and Disability, 1996.
Hobson, D.A. RESNA: Yesterday, Today and Tomorrow,
Assistive Technology, August 1996
Jones, D, Cooper, R, Albright, S, DiGovine, M. Powered
wheelchair driving performance using force and position
sensing joysticks, IEEE, April 1998
Schmeler, MR. Strategies in documenting the need for
assistive technology: An analysis of documentation
procedures. American Occupational Therapy Assoc.,
Technology Special Interest Section Quarterly 7(13) pp. 1-4,
1997
Trefler, E. and Angelo, J. Comparison of Anterior Trunk
Supports for Children with Cerebral Palsy, Assistive
Technology, Vol 1, No 9, 1997
VanSickle, D.P., Cooper, R.A., Robertson, R.N. and
Boninger, M.L., Determination of Wheelchair Dynamic
Load Data for Use with Finite Element Analysis, IEEE
Transactions on Rehabiltiation Engineering, 1996.
Extended Abstracts/Proceedings/Articles
Alva P and Hobson DA. Computer Simulation of Powered
Wheelchair Electro-mechanical Systems. Proceedings of the
RESNA ‘96 Annual Conference, Salt Lake City, Utah, June
1996: 215-216.
Angelo, JA and Trefler E. Surveying Satisfaction of
Integrated Control Users. Proceedings of the RESNA ‘96
Annual Conference, Salt Lake City, Utah, June 1996: 212-214.
Bayles G, Ulerich P, Palmer K, Brienza DM. New Battery
Technology for Powered Wheelchairs. Proceedings of the
17th Annual RESNA Conference, Nashville, TN, June 1994.
Bertocci GE and Hobson DA. The Affects of Securement
Point Location on Wheelchair Crash Response. Proceedings
of the RESNA ‘96 Annual Conference RESNA Press,
Washington DC, June 1996: 49-51.
Bertocci GE. The Affects of Shoulder Belt Anchor Position
on Wheelchair Transportation Safety. Proceedings of the
RESNA ‘95 Annual Conference. RESNA Press, Vancouver,
BC, June 1995: 311-313.
Bertocci, G and Karg, P. Survey of Wheeled Mobility
Device Transport Access Characteristics. Proceedings
RESNA Annual Conference, Pittsburgh, PA, June 1997.
Bertocci, G, Esteireiro, J, Thomas, C, Young, T. Testing and
evaluation of wheelchair caster assemblies subjected to
dynamic crash loading. Proceedings 21st Annual RESNA
Conference, Minneapolis, MN, June 1998
Bertocci, G, Hobson, DA, McCartney, M, Rentschler, A. The
effects of various vehicle floor surfaces on wheelchair
sliding under normal driving conditions. Proceedings 21st
Annual RESNA Conference, Minneapolis, MN, June 1998
Bertocci, G., Digges, K., Hobson, D.A. The Affects of
Wheelchair Securement Point Location on Occupant Injury
Risk, Proceedings RESNA Annual Conference, Pittsburgh, PA,
June 1997.
Boninger ML, Saur T, Trefler E, Hobson D, Burdett R, and
Cooper RA: Postural Changes with Aging in Tetraplea,
Proceedings 21 st Annual RESNA Conference, Minneapolis,
MN, pp. 155-157, 1998.
Brienza D, Gehlot N, Silverman M. A Reusable Mold for
Custom Contour Cushion Manufacturing. Proceedings of
the RESNA ‘95 Annual Conference, Vancouver, BC, June 1995:
303-305.
Brienza D, Gehlot N. Concept and Implementation of a
Force Feedback Active Joystick. Proceedings of the RESNA
‘95 Annual Conference, Vancouver, BC, June 1995: 325-327.
Brienza D.M. and E. Trefler, “Developments in Contoured
Seating Technology”, Workshop, 10 th International Seating
Symposium, Vancouver, BC, Canada, February, 1994.
Brienza DM and Chung K-C. Seat Support Surface
Optimization Algorithm Development. Proceedings of the
1993 ASME Winter Annual Meeting, New Orleans, LA, 1993;
Invited Abstract.
Brienza DM and Brubaker CE. Design and Development
of a Wheelchair for Enhanced Access. Proceedings of the
RESNA ‘96 Annual Conference, Salt Lake City, Utah, June
1996: 250-252.
Brienza DM, Chung K-C, Lin C-T. A Passive Four Degree
of Freedom Digitizing Arm for Seating Surfaces.
Proceedings of the 17th Annual RESNA Conference, Nashville,
TN, June 1994.
Brienza DM. Assisted Control and Navigation of a
Powered Wheelchair, International Ergonomics Association’s
Conference on Rehabilitation Ergonomics, August 1994.
Invited Abstract.
84 RERC ON WHEELCHAIR TECHNOLOGY

Brienza, D.M.: EE Undergraduate Seminar on
Rehabilitation Engineering Research, Pittsburgh, PA,
November, 1993.
Brienza, DM, and Brubaker, CE. A Four Wheel Steering
Mechanism for Short Wheelbase Vehicles. Proceedings Resna
Annual Conference, Pittsburgh, PA, June 1997.
Brienza, DM, Karg, PE. A method for contoured cushion
design using pressure measurements. Proceedings 21st
Annual RESNA Conference, Minneapolis, MN, June 1998
Cooper RA and McGee H. Wheelchair Related Accidents
and Malfunctions. Proceedings of the RESNA ‘95 Annual
Conference, Vancouver, BC, June 1995: 334-336.
Cooper RA, Cooper R, Selecting a Rural Outdoor Mobility
Device, Proceedings 21st Annual RESNA Conference,
Minneapolis, Minnesota, June 1998
Cooper RA, McGee H, Apreleva M, Albright SJ, VanSickle
DP, Wong E, Boninger ML. Static Stability Testing of Standup
Wheelchairs. Proceedings of the RESNA ‘95 Annual
Conference, Vancouver, BC, 1995: 349-351.
Cooper RA, Robertson RN, Boninger ML. A Biomechanical
Model of Stand-Up Wheelchairs. Proceedings 17th Annual
IEEE/EMBS International Conference, Montreal, Canada,
1995.
Cooper, R, Cooper, RA, O’Connor, T, Axelson, P. Back
Support System Effects on Seating During Manual
Wheelchair Propulsion. Proceedings RESNA Annual
Conference, Pittsburgh, PA, June 1997.
Cooper, R.A., Gonzalez, J., Robertson, R.N., and Bonginer,
M.L., NewDevelopments in Wheelchair
Standards, Proceedings 18 th Annual IEEE/EMBS International
Conference, Amsterdam, Netherlands, CD-ROM, 1996.
Evans, J, Hobson, DA, vanRoosmalen, L, Bertocci, G.
Testing of a low ‘g’ prototype securement device.
Proceedings 21st Annual RESNA Conference, Minneapolis,
MN, June 1998
Garand SA and Shapcott N. Computer Aided Wheelchair
Prescription System (CAWPS). Proceedings of the RESNA
‘96 Annual Conference, Salt Lake City, Utah, June 1996: 209-
211.
Geyer, MJ, Brienza, DM, Kelsey, S, Karg, PE, Trefler, E.
Efficacy of seat cushions in preventing pressure ulcers for
at-risk elderly nursing home residents: research issues.
Proceedings 21st Annual RESNA Conference, Minneapolis,
MN, June 1998
Gonzalez, J, Cooper, RA, Rentschler, A, Lawrence, B. Frame
Failure of Welded Manual Wheelchairs. Proceedings RESNA
Annual Conference, Pittsburgh, PA, June 1997.
Hobson DA, Trefler E, Malagodi MS. Redefined Work and
the Role of Assistive Technology. Proceedings of the 2nd
Pittsburgh Employment Conference for Augmentative and
Alternative Communication Users, August 1994.
Hobson DA. 10542-Wheelchair Tiedowns and Occupant
Restraint Systems for Use in Motor Vehicles. ISO/TC173/
SC1/WG-6 Working Document, March 1994.
Hobson DA. Wheelchair Transport Standards: What Are
They All About Proceedings of the RESNA ‘96 Annual
Conference, Salt Lake City, Utah, June 1996: 204-206.
Hobson DA. Proposal for the Development of a National
Standard for Transport Wheeled Mobility Devices. March
1993.
Hobson DA. Securement of Wheelchairs in Motor Vehicles.
Is It Time for a Universal Solution Proceedings of the
RESNA ‘95 Annual Conference, Vancouver, BC, June 1995:
87-89.
Hobson, D.A. Bertocci, G., Bernard, R. McCartney, M.
Wheelchair Transit Safety: A Conceptual Case for a low
‘g’ Securement Approach, Proceedings RESNA Annual
Conference, Pittsburgh, PA, June 1997.
Jones DK, Albright SJ, Cooper RA, Boninger ML,
Computerized Tracking Using Force- and Position-Sensing
Joysticks, Proceedings 21st Annual RESNA Conference,
Minneapolis, Minnesota, June 1998
Karg TE, Brienza DM, Brubaker CE, Wang J, Lin CT. A
System for the Design and Analysis of Seat Support
Surfaces. Proceedings of the RESNA ‘96 Annual Conference,
Salt Lake City, Utah, June 1996: 226-228.
Karg TE, Brienza DM, Chung K, Brubaker CE. Evaluation
of a Surface Shape Optimization Technique for Custom
Contoured Cushion Design. Proceedings of the RESNA ‘96
Annual Conference, Salt Lake City, Utah, June 1996: 229-231.
Karg, P., Bertocci, G., Hobson, D.A. Universal Interface
Hardware Design Standard for Mobility Device Transport
Docking Sytems, Proceedings RESNA Annual Conference,
Pittsburgh, PA, June 1997.
FINAL REPORT: 1993-1998
85

Karg, PE, Bertocci, G, Hobson, DA. Status of universal
interface design standard for mobility device docking on
vehicles. Proceedings 21st Annual RESNA Conference,
Minneapolis, MN, June 1998
Lawrence B, Cooper RA, Robertson RN, Boninger ML,
Gonzalez J, VanSickle DP. Manual Wheelchair Ride Comfort.
Proceedings of the RESNA ‘96 Annual Conference, Salt Lake City,
Utah, June 1996: 223-225.
Malagodi MS, Hobson DA, Robinson CJ. Technical
Identification of a Non-Invasive Spinal/Pelvic Alignment
Monitoring System for Individuals Seated in Personal
Wheeled Mobility Devices. Proceedings of the 17th Annual
Resna Conference, Nashville, TN, June 1994.
Malagodi, M.D., “Technical Identification of a Non-Invasive
Spinal/Pelvic Monitoring System for Individuals Seated in
Personal Wheeled Mobility Devices”. Poster Presentation.
17th Annual RESNA Conference, Nashville, TN. June 1994
Nho WC, Brienza DM, Boston R. The Development of AC
Motor Drive in Power Wheelchair. Proceedings of the RESNA
‘96 Annual Conference, Salt Lake City, Utah, June 1996: 196-
198.
Rushmore, H and Trefler, E. Consumer Participation in
Identifying Manual Wheelchair Prescription Process
Priorities. Proceedings RESNA Annual Conference, Pittsburgh,
PA, June 1997
Rushmore, H and Trefler, E. Consumer Satisfaction in
Multidisciplinary and Nonmultidisciplinary Team
Approaches in Manual Wheelchair Prescriptions. Proceedings
Resna Annual Conference, Pittsburgh, PA, June 1997.
Saur TA, Garand SA, Shapcott N. Computer Assisted
Wheelchair Prescription Program (CAWPS) Survey.
Proceedings of the RESNA ‘96 Annual Conference, Salt Lake City,
Utah, June 1996: 207-208.
Saur, T., Boninger, M., Hobson, D.A., Trefler, E. A Comparison
of Individuals with New C5-7 Injuries vs. Individuals with
Old C5-7 Injuries, Proceedings Resna Annual Conference,
Pittsburgh, PA, June 1997.
Shapcott N, Cooper D, Gonzalez J, Haddow A, Heinrich M,
Hobley D, Savage D. A Proposed Low Cost Cushion Design
for Individuals with Spinal Cord Injury in Developing
Countries. Proceedings of the RESNA ‘96 Annual Conference,
Salt Lake City, Utah, June 1996: 417-419.
Trefler E, Ed. Seating the Disabled, Proceedings of the
Thirteenth International Symposium (1997) University of
Pittsburgh Press.
Trefler E. Single Subject Research: A Research Method for
Seating and Mobility Clinicians. Comparison of Anterior
Trunk Supports for Children with Cerebral Palsy.
Proceedings: The Canadian Seating and Mobility Conference,
Toronto, Canada, Sept 1995:115-117.
Trefler E. Single Subject Research: A Research Method for
Seating and Mobility Clinicians. “Comparison of Anterior
Trunk Supports for Children with Cerebral Palsy.
Proceedings: ARATA Conference, Adelaide, Australia. Oct
1995: 293-295.
Trefler, E. “ Assessment and Training Strategies for Seating,
Positioning and Mobility”, Conference on Everyday Lives,
March, 1994.
Trefler, E. “ Partnerships in Community Applications of
Assistive Technology”, Canadian-American Occupational
Therapy Annual Conference, Boston, July, 1994.
Trefler, E. “Adding Technology to Your Bag of Tricks”,
Austin, TX, March, 1994 and Columbus, OH, May, 1994.
Trefler, E. “Wheelchair and Specialized Seating”, session,
Assistive Technology for Rehabilitation Counselors,
Harrisburg , PA, October, 1993.
Ulerich P, Palmer K, Stampahar M, Brubaker C. Design
and Development of a Wheelchair for Enhanced Access.
Paralyzed Veterans of America, Spinal Cord Research
Foundation, Grant # 1228-01, March, 1994.
van Roosmalen, L, Bertocci, GE, Karg, PE, Young, T. Belt
fit evaluation of fixed vehicle-mounted shoulder restraint
anchor across mixed occupant populations. Proceedings 21st
Annual RESNA Conference, Minneapolis, MN, June 1998
Wang J, Brienza DM, Brubaker CE, Yuan Y. Design of an
Ultrasound Soft Tissue Characterization System for the
Computer-Aided Seating System. Proceedings of the RESNA
‘96 Annual Conference, Salt Lake City, Utah, June 1996: 492-
494.
Wang, J, Brienza, DM, Yuan, Y, Karg, P, Brubaker, CE. A
Compoung Sensor for Biomechanical Analysis for Load-
Bearing Soft Tissue. Proceedings RESNA Annual Conference,
Pittsburgh, PA, June 1997.
86 RERC ON WHEELCHAIR TECHNOLOGY

Books/Chapters
Brienza, DM, Ostrander, LE. Mechanical loading and
pressure ulcers. Surgical Management of cutaneous ulcers
and pressure sores, eds. Lee and Herz, chapter 10, 1997
Christiansen, Baum, Slack, Trefler, Hobson, eds. Assistive
Technology Issues and Application, Occupational Therapy
Practice in Occupational Therapy, Achieving Human
Performance Needs in Daily Living, Book Chapter, 1997.
Hobson DA, Trefler E. Rehabilitation Engineering
Technologies-Principles of Application. Chapter, Biomedical
Engineering Handbook, ed. Joseph Bronzino, 1994.
Hobson DA. Development of Wheelchair Technology.
Chapter in: Seating and Mobility for Persons with Physical
Disabilities, Ed. E. Trefler, Therapy Skill Builders, 1993.
Hobson DA. Standardization of Terminology and
Descriptive Methods for Specialized Seating. Chapter in:
Seating and Mobility for Persons with Physical Disabilities, Ed.
E. Trefler, Therapy Skill Builders, 1993.
Hobson DA. Technology Overview and Classification.
Chapter in: Seating and Mobility for Persons with Physical
Disabilities, Ed. E. Trefler, Therapy Skill Builders, 1993.
Trefler, E and Hobson, DA. Enabling function and wellbeing,
Assistive Technology, eds. Christiansen and Baum, 2nd
ed chapter 20, 1997.
Presentations and Seminars
Bertocci GE. “Special Needs in Student Transportation”,
Pupil Transportation Association of Pa. 25th Anniversary
Conference, State College, PA, June 1996.
Brienza D.M., Schuch J, and Sprigle S. “Wheelchair Seating
and Positioning: Improving Your Services from Assessment
Through Follow Up.” University of Virginia, Charlottesville,
VA, September 22 and 23, 1995. Continuing Education
Workshop.
Brienza, D.M. RESNA Annual Conference, Session Chair,
“Seating and Positioning Technology.” Salt Lake City, Utah,
June 1996.
Cooper, RA, Approach to rehabilitation, Ankara Numune
Hospital & University of Pittsburgh Medical Center 1st Joint
Symposium, Ankara, Turkey, May 1997
Cooper, RA, Wheelchair Selection-Using Standards
Information in the Process, RESNA ’97, Pittsburgh, PA ’97
Cooper, RA Design of Power Wheelchairs, Int. Conf on
Wheelchairs and Seating, Dundee, Scotland, Sept 1997
Cooper, RA Design of High Performance Manual
Wheelchairs, International Conference and Seating,
Dundee, Scotland, Sept 1997
Cooper, RA Secondary Disability and Wheelchair Use,
International Conference on Wheelchairs and Seating,
Dundee, Scotland, Sept 1997
Cooper, RA Sports fitness equipment for people with
disabilities, Sports and Fitness for Individuals with
Disabilities, Springfield College, Springfield, MA May 1997
Hobson, D.A. and Bertocci, G. Wheelchair Transportation
Safety Workshop, RESNA Conference, Pittsburgh, PA, June
20, 1997.
Hobson, D.A. and Bertocci, G.E. Transporting Students
with Disabilities: Wheelchair Safety, Education Service
Center, Houston, TX, February 21, 1997.
Hobson, D.A. and Bertocci, GE. Wheelchair Transportation
Industry Update, RESNA, 1996 Mid Atlantic Regional
Planning Committee Conference, Philadelphia, PA,
November 16, 1996.
Hobson, D.A. Overview of Activities in the Rehabilitation
Engineering Program, Disability Awareness Days,
Pittsburgh, PA, October 4, 1996.
Hobson, D.A. Wheelchair Standards, Assistive Technology
Training Program, University of Pittsburgh, Pittsburgh,
PA, March 13-15, 1977.
Hobson, D.A., Bertocci, G.E. and Karg, P.E. Wheelchair
Transportation Safety Seating Symposium Preconference
Workshop, ISS, Pittsburgh, PA, January 22, 1997.
Hobson, DA, Bertocci, G, Karg, PE. “Wheelchair
Transportation Safety Workshop”, Transporting Students
with Disabilities Conference, March 5-6, 1996, Birmingham,
AL.
Hobson, DA, Bertocci, G. “Factors Influencing Wheelchair
Transportation Safety”, Vancouver International Seating
Symposium, March 1996.
FINAL REPORT: 1993-1998
87

Hobson, D.A., “Australian Conference on Technology for
People with Disabilities”, keynote address, Adelaide,
Australia, July 1993.
Hobson, D.A., “Principles of Proper Seating for Persons
with Disabilities”, Expo ’94 Conference, Ohio Technology
Related Assistance Information Network (T.R.A.I.N.),
Columbus, OH, May, 1994
Hobson, D.A., “Service Delivery Models for Assistive
Devices”. Annual Conference of Pennsylvania, Association
of Rehabilitation Facilities, Pittsburgh, PA, September 23,
1993
Hobson, D.A., “Status Report on Development of Center
for Assistive Technology”, SHRS, Board of Visitors,
Rehabilitation Technology Program Development, Spring,
1994
Karg, P. “Update on Wheelchair Transportation
Standards”, Breakout Session-5th National Conference and
Exhibition on Transporting Students with Disabilities,
Birmingham, AL, March 1996.
Karg, P. Session Chair, “Wheelchair and Seating
Biomechanics”, RESNA 19th Annual Conference, Salt Lake
City, UT, June 1996.
Karg, P., Bertocci, G., “Wheelchair Transportation Safety
Standards Update and Factors Influencing Wheelchair
Transportation Safety”, Pittsburgh Assistive Technology
Association (PATA) Meeting, February 1996.
Schmeler, M.R. et al. Introduction to wheelchair seating
and mobility. Preconference workshop, ISS, Pittsburgh, PA
January 1997.
Schmeler, M.R. Wheelchair seating and mobility in longterm
care facilities. Vencor, Inc. therapists and
rehabilitation managers, Clarkston, WA, May 1997.
Schmeler, M.R. Wheelchair seating and mobility. Beverly
Health Systems rehabilitation managers. Spokane, WA.
October 1996.
Schmeler, M.R. “Powered Mobility: Alternative and
integrated controls.” NYSOYA Annual Conference,
Fishkill, NY, October 1995.
Schmeler, M.R. “Reasonable accommodations: Providing
assistive technology assessments and interventions in the
workplace.” Westchester Consortium of Vocational
Counselors, White Plains, NY, September 1995.
Schmeler, M.R. “Strategies for powered mobility evaluation
and readiness training.” AOTA 76th Annual Conference,
Chicago, IL, April 1966.
Schmeler, M.R. et al. Rehabilitation Technology Supplier
Modular Training Course. University of Pittsburgh,
Pittsburgh, PA. March 1997.
Schmeler, M.R., “Positions for Function: Seating and
workstations in the classroom.” RESNA 19th Annual
Conference, Salt Lake City, UT, June 1996.
Schmeler, M.R., Angelo, J.A., Doster, S., Larson, B., Ellexson,
M. and Armstrong, F. Assistive Technology as a reasonable
accommodation. AOTA 77th Annual Conference, Orlando,
FL, April 1997.
Schmeler, M.R., Brienza, D. and Shapcott, N. Wheelchair
seating: Seat cushion selection. RESNA Mid-Atlantic
Regional Conference, Philadelphia, PA November 1996.
Schmeler, M.R., Shapcott, N. Dugan, J. Petersen, B.,
Pelleschi, T. Sanna J. and Lego, F. Strategies for providing
model assistive technology services within vocational
rehabilitation. RESNA Annual Conference, Pittsburgh, PA
June 1997
Schmeler, M.R., Shapcott, N. Pelleschi, T. and Dugan, J.
Assistive Technology Service Delivery. Mt. Aloysius
College OT/PT faculty. Cresson, PA. August 1996
Trefler, E. “Single Subject Research: A Research Method
for Seating and Mobility Clinicians. “Comparison of
Anterior Trunk Supports for Children with Cerebral Palsy.”
The Canadian Seating and Mobility Conference, Toronto,
Canada, Sept 1995.
Trefler, E. and Angelo, J. “Surveying Users of Integrated
Controls - A Pilot Study.” Proceedings, ARATA pp. 17-19.
Adelaide, Australia, Oct 1995.
Trefler, E. “Single Subject Research: A Research Method
for Seating and Mobility Clinicians. “Comparison of
Anterior Trunk Supports for Children with Cerebral Palsy.”
ARATA Conference, Adelaide, Australia. Oct 1995.
Trefler, E., “The Use of Integrated Controls: Comparison
of Anterior Trunk Supports for Children with Cerebral
Palsy”. ISS 12th Annual Conference, Vancouver, BC, Feb
1996.
88 RERC ON WHEELCHAIR TECHNOLOGY

Technical Reports
Bayles G. New Power Source Technologies for Electric
Wheelchairs. Technical Report #2, University of Pittsburgh
RERC on Wheelchair Mobility, Pittsburgh, PA, Sept 1994.
Bertocci G, Hobson DA, Digges K. The Affects of Shoulder
Belt Anchor Position on Wheelchair Transportation Safety.
Technical Report #4, University of Pittsburgh RERC on
Wheeled Mobility, Pittsburgh, PA, Jan 1995.
Bertocci GE, Karg P, Hobson D. Wheelchair Classification
System and Database Report. Technical Report #6, University
of Pittsburgh RERC on Wheeled Mobility, Pittsburgh, PA,
Apr 1996.
Digges K and Hobson DA. Fitting Motor Vehicle Shoulder
Belts to Wheelchair Occupants. Technical Report #1, University
of Pittsburgh RERC on Wheeled Mobility, Pittsburgh, PA,
Jul 1994.
Digges K, Bertocci G. Application of the ATB Program to
Wheelchair Transportation”. Technical Report #3, University
of Pittsburgh RERC on Wheeled Mobility, Pittsburgh, PA,
Nov 1994.
Malagodi M and Hobson DA. Spinal/Pelvis Alignment
Monitoring of Wheelchair Users. Technical Report #5,
University of Pittsburgh RERC on Wheeled Mobility, Pgh,
PA, Mar 1996.
Standards Documents
Digges K. Modeling Wheelchair Tiedowns with Wheel
Stiffness Variations. ISO TC173/SC-1/WG-6. April, 1994.
Hobson DA. WD 7176/19, Wheelchairs-Wheeled Mobility
Devices for Use in Motor Vehicles. ISO/TC173/SC1/WG-
6Working Draft, March 1994.
Hobson DA. Wheelchair Tiedowns and Occupant Restraint
Systems for Use in Motor Vehicles. SAE Working Document,
March 1994.
Grants
Bertocci, G, Crash Performance Evaluation Injury Risk
Assessment and Recommendatios for Wheelchair Seating
Systems Used in Motor Vehicles, Center for Disease Control
and Prevention, $615, 550, 9/1/98-8/31/03
Bertocci, G, Development of a Gait Powered Battery Charged
System, SBIR, 9/96-1/97, $100,000
Bertocci, G, Infuence of Wheelchair Seating System
Characteristics/Positioning on Wheelchair Occupant Injury
Risk, $216,836, PVA, 1/1/99-12/31/01
Brienza, D., Scientific Visits To National and International
Seating Labs, Barco Faculty Development Funds, School
of Health and Rehabilitation Sciences, 1995-96, $5,000.
Brienza, D, An Ultrasound Device for Distortion
Measurement and Biomechanical Analysis of in vivo Load
Bearing Soft Tissue, Paralyzed Veterans of America, Spinal
Cord Research Foundation, October 1995 to June 1998,
$150,000.
Brienza, D, Seat Design for Optimal Load Transfer to Soft
Tissues, National Institutes of Health, NCHHD, NCMRR,
R01 HD30161, Oct. 1992 to August 1995. $330,000
Brienza, D, An Innovative Wheelchair Cushion Contour
Generator, Ben Franklin Technology Center of Western
Pennsylvania, SW.S11514R-1, Sept. 1994 to August 1995.
$34,797
Brienza, D, A Pilot Study for the Clinical Evaluation of
Pressure Relieving Seat Cushions for Elderly Stroke
Patients, Dept of Ed, $249,249, July 1997-June 1999
Brubaker, C and Brienza, D, Research Training in
Rehabilitation Science with Special Emphasis on Disability
Studies, Dept of Ed, $706,525, Sept 1997-August 2002
Cooper, R, Robinson, C, Robertson, Boninger, Albright,
VanSickle, Design and Selection Guidelines for Wheelchair
Ride Comfort, $465,000, 1994-1997, U.S. Department of
Veterans Affairs
Cooper, R, 7 Speed Coaster – Brake Hub System for Manual
Wheelchairs, April 14, 1997-October 31, 1998, $31,975,
ARTSCO, NIH
Cooper, R, Center for Injury Research Control, $265,000,
January 1998-August 2003
Cooper, R, Boninger, M and Robertson, R, 1996-
1999.Manual Wheelchair User Upper Extremity Pain, B869-
RA, U.S. Department of Veterans Affairs, $503,300,
Wheelchair Propulsion Biomechanics and Arm Pain,
National Institutes of Health - NCMRR Clinical
Investigator Award, $356,750, (Principal Investigator:
Boninger, Faculty Mentors: Cooper, Fu, Co-Investigators:
Robertson, Towers, 1995-2000.
FINAL REPORT: 1993-1998
89

Cooper, R Angelo, J and Trefler, E, Rehabilitation
Engineering and Assistive Technology Training,
H129E50008, U.S. Department of Education, $310,000,
1995-1998.
Hobson, DA and Brubaker, C, Rehabilitation Engineering
and Research Center on Technology to Improve Wheeled
Mobility, National Institute on Disability and
Rehabilitation Research, HE133005, $3,500,000, August
1993 to July 1998.
Hobson, DA, Development of a Docking System for
Wheelchair Securement, SBIR, 11/29/95, NIH, $57,384, Oct
97-Sept 98
Hobson, DA, Evaluation of a Wheelchair-Integrated
Restraint System, SBIR, 10/1/97-3/31/97
Hobson, DA, Spinal Pelvic Alignment Monitoring of
Wheelchair Users, ARTSCO, NIH, $99,780, October 1997-
March 1998
Hobson, Douglas - Everest & Jennings Distinguished
Lecturer Award, RESNA, ’96
Trefler, Elaine - Mundy Award, Canadian Adaptive Seating
and Mobility Association, ’95
Trefler, Elaine – Fellow, RESNA, ‘96
Patents
C. E. Brubaker, D.M. Brienza and M.J. Brienza, “Reusable
Die Shape for the Manufacture of Molded Cushions,”
Patent No. 5,470,590, Nov. 28, 1995.
D.A. Hobson, Low “g” Wheelchair Securement Device,
patent pending, 1997.
Disclosures
D.A. Hobson, High “g” wheelchair securement
device, 1998.
Shapcott, N and Robinson, C, Computer Aided Wheelchair
Prescription System, Rehabilitation Research and
Development Service, 1994-1996, $262,000, Department of
Veterans Affairs
Trefler, E, Staff Development for Rehab Technology
Supplier Education, Barco Faculty Development Funds,
School of Health and Rehabilitation Sciences, 1995-96,
$20,000.
Trefler, E, Rehabilitation Supplier Education, Frost
Foundation, 1995-96, $20.000.
Honors and Awards
Bertocci, Gina - RESNA/Whitaker Scientific Paper
Competition Award, June 1997
Brienza, David - RESNA Sore Butts Cushion Design
Competiion, First Place, June 1996
Brienza, David - The PinDot Award for outstanding paper
published in Assistive Technology, 1995
Cooper, Rory – PVA John Farkas Leadership Award, ’97
Cooper, Rory – Certificate of Recognition, Federal
Employee Disability Program Committee, Federal
Executive Board, Pittsburgh, PA, ‘97
Cooper, Rory – American Institute of Medical and
Biological Engineering (AIMBE) Fellow ‘98
90 RERC ON WHEELCHAIR TECHNOLOGY

VI. PEOPLE: 1993-1998
RERC STAFF
Jennifer Angelo Task Leader, PM-5; Co-investigator, PM-3
Michael Boninger Task Leader, S-4
Gina Bertocci Task Leader, T-1; Co-Investigator: T-2, T-3, T-4
David Brienza Task Leader: PM-1, PM-3, S-1, S-2; Co-investigator: PM-2, PM-6, MM-1;
Coordinator of Student Research Training
Clifford Brubaker Project Co-director; Task Leader: PM-2, MM-1; Coordinator Technology
Transfer
Rory Cooper
Task Leader, STD-1
Steven Garand Co-investigator, WP-2
Douglas Hobson Project Co-Director; Task Leader: PM-1, PM-6, PM-7, T-2, T-3, T-4;
Co-investigator: PM-2, S-4, T-1
Patricia Karg Co-Investigator: PM-3, S-1, S-2, T-2, T-4
Jorge Letechipia Student Training
Mark McCartney Senior Machinist; Co-investigator: PM-1, PM-6, T-3
Ashli Molinero Communication Specialist
Mark Schmeler Co-investigator, PM-7
Nigel Shapcott Co-investigator: PM-7, WP-2, STD-1; Consumer Training
Elaine Trefler
Task Leader, WP-1; Co-investigator: PM-5, S-4; Coordinator of Dissemination
Jean Webb
Administrative Assistant
RERC ADVISORY COUNCIL
Peter Axelson
Bruce R. Baker
John L. Bernard
William Chrisner
Linda Dickerson
Cyndi Jones
Allan R. Sampson
Michael Silverman
Larry A. Sims
Director, Research and Development and President, Beneficial Designs, Inc.,
Santa Cruz, CA
Linguist, Semantic Compaction Systems, Pittsburgh, PA
Program Coordinator, Institute of Advanced Technology, Pittsburgh, PA
President and Executive Director, Three Rivers for Independent Living,
Pittsburgh, PA
President and Publisher, Executive Report Magazine, Pittsburgh, PA
Publisher, Mainstream Magazine, San Diego, CA
Professor and Group Leader, Statistics, University of Pittsburgh, PA
President, Pin Dot Products, Inc. Northbrook, IL
President, Sims Tech, Niceville, FL
FINAL REPORT: 1993-1998
91

CONSULTANTS
Jules Legal
Steve Stadelmeier
Ted Heinrich
Kim Henry
Phil Ulerich
Catherine Palmer
Tod Oblak
Mechanical Designer, Innoventions Inc.
Industrial Designer, Carnegie Mellon University
Project Engineer, Westinghouse Corp.
Rehab. Engineer, Rehabilitation Center of PGH
Project Engineer, Westinghouse Corp.
Project Engineer, Westinghouse Corp.
Project Engineer, Westinghouse Corp.
STUDENTS
Name DegreeProgram Task(s)
Preetam Alva, BS, MS ME Ph.D. ME PM1, PM6
Thomas Ault, BS Computer Eng. Ph.D. CS S2
Randy Bernard, BS, MS Ind. Design Ph.D. SHRS PM6
Gina Bertocci, MS Ph.D. Bioeng. T1-4
Dalthea Brown, MS Physical Therapy Ph.D SHRS
S4, S5
Jonathan Evans, Undergraduate B.S. M.E. PM1, PM 6
Jess Gonzalez, BS M.S. Bioeng. STD1
Thomas O’Connor, B.S. Ph.D. SHRS STD1
Khondukar Mostafa, BS EE M.S. EE PM1b, S3
Wonchul Nho, BS, MS EE Ph.D. EE PM1c, PM3, S1,S3
James Protho, BS CS M.S. RST PM3, S1
Heather Rushmore, BS Speech Path. M.S. RST WP1
Tracy Saur, BS Occupational Therapy M.S. OT
S4
Jue Wang, BS EE, MS Bioeng. Ph.D. RST S1, S2
Linda van Roosmalen Ph.D SHRS T-2, T-3, PM-6
Tom Bursick, B Sc. MSc. RST S-6
Bert Joseph, OTR M Sc. RST S-6
Mary Ellen Buning, OTR Ph.D SHRS Dissemination
Mary Jo Geyer, RPT Ph.D. SHRS S-1
FOCUS GROUP PARTICIPANTS
Name Affiliation Task Participation
Donald Mervis Center for Independent Living PM-1, PM-3, T-4
Sally Murray Center for Independent Living PM-3, T-1, T-3
John Zorne Consumer PM-3, PM-5
Joe Kiren PVA MM-1, STD-1
Robert Schneider Westinghouse PM-6, T-1, T-2, T-3, T-4
Janet Schneider OVR PM-6, T-1, T-2, T-3
John Sikora Harmarville Rehab Ctr MM-1
92 RERC ON WHEELCHAIR TECHNOLOGY

Sanford Blatt Consumer PM-3, S-2
Paul Dick Consumer PM-6, T-2, T-3
Lucy Spruill Cerebral Palsy Fdn PM-6, T-2, T-3
Ruth Breyno Consumer T-3
Allan Sampson University of Pittsburgh S-1
D.J. Stemmler Center for Independent Living S-1
Lisa Goodall Consumer S-4
Robert Cerminara Consumer S-4
Tina Williams Consumer S-4
Scott Williams Consumer S-4
Todd Albright Consumer S-4
BIOGRAPHIES OF DIRECTORS AND TASK LEADERS
Jennifer Angelo, Ph.D., OTR, Task Leader: PM-
5, is an Assistant Professor in the Department of
Occupational Therapy at the University of Pittsburgh.
She has knowledge of the problems faced by users of
integrated controllers. Prior to her present
appointment, she was at the State University of New
York at Buffalo. There she was the primary
investigator for a three year grant from the US
Department of Education, Rehabilitation Services
Administration’s and the co-investigator on a project
from the Social Security Administration
Demonstration Grants Program. Within these two
grants she surveyed users of technology in the work
place and helped persons with physical disabilities
return to employment. A portion of the users she
surveyed and helped return to work used integrated
controllers. She brings this knowledge base to the
current project, as well as from at least two other
research projects related to access to electronic
assistive devices.
Gina E. Bertocci, Ph.D., P.E., Task Leader: T1, is
an Assistant Professor with the Department of
Rehabilitation Science and Technology at the
University of Pittsburgh. She graduated from the
University of Pittsburgh with a BS and MS in
Mechanical Engineering, and a Ph.D. in
Bioengineering. Dr. Bertocci conducts research in the
area of wheelchair transportation safety, biodynamics
modeling and injury biomechanics. As a part of the
University’s NIDRR Rehabilitation Engineering
Research Center, her research has focused on the
investigation of parameters, which influence injury
risk of wheelchair occupants in motor vehicle
accidents. Dr. Bertocci is a member of the ANSI/
RESNA committee charged with the development of
the Transport Wheelchair Standard (WC-19) and
provided research support for the ISO and SAE
wheelchair transportation standards efforts.
Michael Boninger, MD, Task Leader: S-4, is an
Assistant Professor and Research Director in the
Department of Orthopaedic Surgery, Division of
Physical Medicine and Rehabilitation. He also holds
adjunct appointments in the Department of
Rehabilitation Science and Technology and the
Department of Mechanical Engineering. Dr. Boninger
also serves as the co-director for the
Electromyography Laboratory at UPMC Health
System. He graduated from the Ohio State University
with degrees in both medicine and engineering. He
received his specialty training in Physical Medicine
and Rehabilitation at the University of Michigan
Medical Center where he served as Chief Resident.
After his residency program, he completed an NIDRR
Fellowship in Assistive Technology at the University
of Pittsburgh. He is the Director for the Center for
Assistive Technology at the UPMC Health System
FINAL REPORT: 1993-1998
93

and also serves as its Medical Director. This clinic
incorporates many disciplines in order to provide
patients with the most appropriate assistive
technology (rehabilitation engineering, occupational
therapy, physical therapy and rehabilitation
medicine). Dr. Boninger also serves as the Medical
Director of the Human Engineering Research
Laboratories. His research interests include causes
of upper extremity pain in individuals who rely on
manual wheelchairs for mobility, fall prevention in
the elderly, wheelchair biomechanics, and
appropriate utilization of assistive technology.
David M. Brienza, Ph.D., Task Leader: S-1, S-2,
is an Assistant Professor in the School of Health and
Rehabilitation Sciences. He received the B.S. degree
in electrical engineering from the University of Notre
Dame, South Bend, Indiana, in 1986, and the M.S. and
Ph.D. degrees in electrical engineering from the
University of Virginia, Charlottesville, Virginia, in
1988 and 1991, respectively. From 1987 to 1991 he
worked as a research assistant at the Rehabilitation
Engineering Center at the University of Virginia. In
1991 he joined the faculty of the University of
Pittsburgh, with a secondary appointment in the
Department of Electrical Engineering. His particular
areas of expertise are control theory and soft tissue
biomechanics. Dr. Brienza is a member of IEEE,
RESNA, and the Pittsburgh Assistive Technology
Association—a local organization of professionals
and consumers dedicated to sharing information
concerning assistive technology.
Clifford Brubaker, Ph.D., Project Co-Director,
Task Leader: MM-1, has been Professor and Dean of
the School of Health and Rehabilitation Sciences and
Professor of Industrial Engineering since July 1991.
Dr. Brubaker was formerly the Director of the UVA-
REC for Wheelchairs and Seating Design from 1987
to 1991. During this period, the Center established
its leadership reputation in research and design
efforts for innovative wheelchair design and CAD/
CAM seating, and he has three patents pending in
this area. He is a fellow of both RESNA and American
Institute on Medical and Biological Engineering
(AIMBE). He has served as President of RESNA since
January 1995.
Rory Cooper, Ph.D., Task Leader: STD-1, is
currently an Associate Professor and Director of the
Pitt/VAMC Human Engineering Research
Laboratories and of the Rehabilitation Engineering
Program (REP) and Chair, Rehabilitation Science and
Technology in the School of Health and Rehabilitation
Sciences at the University of Pittsburgh. Prior to
coming to Pittsburgh, he was an Associate Professor
of Biomedical Engineering at California State
University, Sacramento. Dr. Cooper is also a research
scientist at the Highland Drive VAMC (Pittsburgh).
Dr. Cooper is a Senior Member of IEEE. He was the
1993 recipient of the IEEE-EMBS Early Career
Achievement Award. Dr. Cooper has made
significant contributions to research and development
in the field of rehabilitation engineering. He has close
relationships with several companies in the areas of
rehabilitation product design. He has developed a
Biomechanics and Neuromotor Control Laboratory
to study upper extremity pain among wheelchair
users. Dr. Cooper has authored or co-authored more
than seventy-five papers, expanded abstracts, and
book chapters. Dr. Cooper is a member of the
RESNA/ANSI and ISO Wheelchair Standards
Committees. He is also a Trustee of the Paralyzed
Veterans of America Spinal Cord Research
Foundation, and on the board of directors of the Tri-
State PVA Chapter.
Kennerly Digges, Ph.D., Task Leader: T-1,
received his advanced degrees from Ohio State
University. Dr. Digges managed the DOT-NHSTA’s
research division for 12 years, during which time he
was dedicated to the advance of motor vehicle safety
standards. In this capacity he directed hundreds of
research projects resulting in more than 1000
authoritative technical reports dealing with auto
safety. He retired from DOT in 1989 and was the
Director of the Transportation REC at the University
of Virginia from 1991-92. Since 1986, he has had over
20 publications. At this time Dr. Digges is using his
vast experience in crash safety as a private consultant,
and has an adjunct faculty appointment at the
University of Pittsburgh.
94 RERC ON WHEELCHAIR TECHNOLOGY

Douglas A. Hobson, Ph.D., RERC Co-Director,
Task Leader: PM-6, S-3, T-2, T-3, T-4, is an Associate
Professor in the Department of Rehabilitation Science
and Technology and is Director of the Rehabilitation
Technology Program (RTP). The RERC is located
within the RTP giving it a direct affiliation with the
Center for Assistive Technology, our service delivery
center. Dr. Hobson began and directed the
Rehabilitation Engineering Program at the University
of Tennessee, Memphis, TN from 1974 to 1990. It is
recognized world-wide for its contribution to the field
of specialized seating and mobility. During the years
from 1976-81, the UT program was awarded a NIHR–
REC grant for research and development of seating
technology. Four product developments that occurred
during this period are currently being marketed by
commercial suppliers. Many of the seating principles
now being taught to clinicians and suppliers were
developed and communicated by the UT staff. The
UT program co-hosted the International Seating
Symposium, which is the single largest annual event
in the seating field. He currently serves as chairman
of the SAE, ISO, and the ANSI/RESNA-SOWHAT
standards committees related to wheelchair
securement and transport wheelchairs. Dr. Hobson
served as the President of RESNA during the period
1991-92, and is currently Chairman of the Education
Committee.
Nigel Shapcott, M.Sc., Task Leader: WP-2,
received a B.Sc. (Hons.) in Mechanical Engineering
from Thames Polytechnic and an M.Sc. in
Biomechanics from the University of Surrey, both
while living in the UK. Nigel’s previous position was
Director of the Rehabilitation Technology Service
Delivery and Development Programs at the State
University of New York in Buffalo. He is currently
working on developing Assistive Technology Service
Delivery Programs in Western Pennsylvania. He has
recently been awarded a VA grant to develop a
Computer Aided Wheelchair Prescription program
and continues a long term commitment to the
development of ANSI and ISO Wheelchair Standards.
Nigel is also active in the transfer of appropriate
Assistive Technology to developing countries.
Elaine Trefler, M.Ed., OTR, FAOTA, Task
Leader: S-5, S-6, Training, is trained as a physical and
occupational therapist and has specialized in the
application of assistive technology for persons with
physical disabilities. Her area of special interest is
seating and wheeled mobility. She has published
widely and is responsible for many continuing
education seminars and symposia in the broad scope
of assistive technology. Specifically, she is responsible
for the International Seating Symposium when it is
held in the United States and numerous training
programs for therapists and rehabilitation technology
suppliers on topics related to seating and wheeled
mobility. Ms. Trefler has been on the Executive
Committee of RESNA and is currently on the Board
of Directors and is Secretary. She has been awarded
the honor of Fellow in the American Occupational
Therapy Association for her contribution in the area
of assistive technology. She is involved in
coordinating the dissemination plans for the RERC,
which include continuing education programs, inservice
programs and the writing of articles for
publication. She participates in several research
projects and teaches in the departments of
Rehabilitation Science and Technology and
Occupational Therapy.
FINAL REPORT: 1993-1998
95

INFORMATION
For further information regarding the RERC, please contact:
Douglas A. Hobson, Ph.D. and Clifford E. Brubaker, Ph.D.
Co-Directors
Rehabilitation Engineering Research Center
University of Pittsburgh
School of Health and Rehabilitation Sciences
Department of Rehabilitation Science and Technology
Room 5044, Forbes Tower
Pittsburgh, PA 15260
Phone 412/647-1270, Fax 412/647-1277, TDD 412/647-1291
This report is available in disc format, and can also be downloaded or printed from our Web site.
For updated information and current RERC activities, please visit our Web site at:
www.rerc.upmc.edu
Primary Support :
National Institute on Disability and Rehabilitation Research (NIDRR) Grant No. H133E30005

Rehabilitation Engineering Research Center
University of Pittsburgh
School of Health and Rehabilitation Sciences
Department of Rehabilitation Science and Technology
Room 5044, Forbes Tower
Pittsburgh, PA 15260
Phone 412/647-1270 • Fax 412/647-1277 • TDD 412/647-1291
www.rerc.upmc.edu