Another Hardware-In-The-Loop (HWIL) - Acutronic

EDITORIAL
Dear Customers,
Partners and
Friends of
ACUTRONIC!
Welcome to the second
edition of the
ACUTRONIC Newsletter
and welcome to the
new year. As with
many others I am happy to leave
the old year, which surely will find
its place in the history books all
around the world, behind me.
Together with the team from
ACUTRONIC, I now look forward
to a new year with new opportunities,
new challenges and new findings.
You will find some changes to the
newsletter since we incorporated
the feedback from many of our
readers. For example, we have
now integrated a “Customer Corner”
where we place some “reallive
reports” from guest authors.
We start in this edition with an
article from Dr. Weissenborn from
the German Metrological Institute.
Furthermore, we are more
than pleased to announce a
Technology Report from Howard
S. Havlicsek, our Chief Technology
Officer. He introduces the
next generation of the Acutrol ®
Motion Controller.
Once again, all the best for 2002!
Sincerely,
Thomas W. Jung
Newsletter
Thomas W. Jung,
CEO ACUTRONIC
Group.
Contents
Editorial, by Thomas W. Jung .......... 1
ACUTRONIC USA Receives Multimillion
Contract Award
by Dennis Whitehead ....................... 1
Acutrol ® 3000 Instrumentation
Promises a Natural Transition
by Howard Havlicsek ....................... 2
Another Hardware-In-The-Loop
(HWIL) System from ACUTRONIC
by Colin Stevens & Peter Hofstetter .. 3
ACUTRONIC USA Upgrades
Carco Model 53M-3 Three Axis
Motion Simulator
by Dennis Whitehead ....................... 4
1
ACUTRONIC NEWSLETTER
Issue 2 – January 2002
ACUTRONIC USA
Receives Multi-million
Dollar Contract Award
for a Helicopter
Hardware-in-the-Loop
Simulation System
by Dennis Whitehead,
ACUTRONIC USA
ACUTRONIC USA, Inc. has been
selected by a major U.S. prime contractor
to design and manufacture a
helicopter environmental simulation
system centered on three large motion
tables. This hardware-in-the-loop simulation
system will provide our customer
with the unique ability to investigate
helicopter dynamic behaviour in the
laboratory. ACUTRONIC is under
contract to provide a “turn-key” simulation
system that includes the three
motion simulators, the hydraulic power
supply with piping, individual motion
simulator control consoles, a system
control console with command and
data acquisition instrumentation along
with system installation, integration and
startup at the customers facility.
In 2001 ACUTRONIC participated
at main aerospace events
by Reinhard Hoffmann .................. 5
Realization and Dissemination
of Mechanical Motion Quantities
by Dr. Christof Weissenborn ...... 6-7
3D Motion Simulator for
investigations of the human
balance system
by Prof. Dr. med. Bernhard Hess ... 8
Contents ..................................... 1
Impressum ................................. 8

ACUTRONIC NEWSLETTER
Acutrol ® 3000 Instrumentation Promises a Natural Transition
Into the Next Generation of Motion Control
by Howard Havlicsek, ACUTRONIC R&D USA
ACUTRONIC Research and Development
(Pittsburgh, PA) is actively working on a next
generation motion control instrumentation, called
the Acutrol3000. Prototypes are currently being
tested and demonstrated.
The Acutrol ® ACT 2000 ® is the
principal motion controller used by
ACUTRONIC since the early 90’s, and
has become an industry standard for
high performance and reliability. From
this legacy, the Acutrol3000 emerges
offering a mix of features that provide a
bridge to the future.
The Acutrol3000 was developed with
the following objectives:
• Cost reduction by the use commercial
off-the-shelf processors and
interface modules.
• Minimization of custom hardware
using highly integrated FPGA technology.
• High reliability (long MTBF) and
‘calibrated’ transparency of hardware
modules (short MTTR).
• Commercial interfaces, which
provide consistent protocols for realtime
and language based communication.
• An operator interface offered as an
option rather than a requirement of
the instrumentation.
• Pure MACRO programming features
embedded in the control software
using the Python language.
• Backward compatibility of principal
interfaces to facilitate upgrading
from the Acutrol ACT2000.
• Asynchronous interfacing to realtime
HWIL computers using event
driven time-tags.
2
The Acutrol3000 instrumentation will
be offered with various chassis configurations
to satisfy a range of system
requirements. User Interface options
include an integrated touch panel PC,
a separate panel or desktop PC, or no
local interface. The heart of the control
system includes the LynxOS real-time
operating system running on a Pentium
® + platform; and, a custom Axis
Interface Module (AIM) that provides
autonomous data acquisition of
analog and digital signals for one axis
of motion control.
The ACUTRONIC Control Language
(ACL) is used to communicate via non
real-time interfaces such as
IEEE488.2 and TCP/IP protocols. This
control language is based on the
GPIB interface protocol of the Acutrol
ACT2000 and is greatly expanded to
allow control, configuration, monitoring,
and calibration of all aspects of
the instrumentation. Data logging is
provided as a new feature and includes
multi-channel, event and level
trigger modes with min, max, and
multi-set averaging.
Traditional control modes (Position,
Rate, Track, and Synthesis) are
implemented using an advanced
JERK limited profiler that ensures
smooth profiles and seamless transitions.
An expansion of Track mode
provides for various configurations of
real-time control based on host computer
frame rates, frame synchronization,
and the complement of motion
demand states. Real-time interfaces
are implemented using either parallel
PCI-DIO32HS(NI), or SCRAMNet ®
(Systran) interface hardware.

Another Hardware-In-The-Loop
(HWIL) System from ACUTRONIC
by Colin Stevens & Peter Hofstetter,
ACUTRONIC Switzerland
ACUTRONIC Switzerland delivered and successfully
installed a three-axis, high dynamic Flight
Motion Simulator (FMS), Series HD7747. The system
was designed, manufactured and integrated
within the short time frame of fourteen months.
3-axix flight motion
simulator model
HD7747 with test Unit
Under Test (UUT)
and ACUTROL ®
control console.
The FMS will be used within a RF
environment and utilises an electrically
driven translation carriage to locate the
FMS into the anechoic chamber. In
order to achieve the high dynamic
requirement the axes were driven by
hydraulic actuators.
The inner axis achieves accelerations
of 35’000 0 /s 2 ; the middle and outer
axes exceed 10’000 0 /s 2 .
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ACUTRONIC NEWSLETTER
Although ACUTROL ® is a digital
controller it is able to accept and
process inputs from analogue
transducers. These analogue inputs
can be scaled digitally and routed to
the digital servo loop. This feature of
ACUTROL ® was used to process the
input of accelerometers that were
installed on the inner axis. The signals
from the accelerometers gave feedforward
compensation to the servo
loop in order to reduce the phase lag of
the axis.
With the load attached and a constant
input amplitude of 0.5 0 peak to peak,
we achieved less than -10 0 phase lag
at 10Hz. The amplitude was within
+1dB from 0Hz to 30Hz.
For real time motion control from the
customer’s computer a high speed
reflective memory interface
(SCRAMNet ® ) was installed into the
ACUTROL ® mainframe.
Rear view of
simulator showing
accumulators,
translation carriage
and pipe work.

ACUTRONIC NEWSLETTER
ACUTRONIC USA Upgrades Carco Model 53M-3
Three Axis Motion Simulator
by Dennis Whitehead, ACUTRONIC USA
ACUTRONIC USA, Inc. has just delivered a
refurbished Model 53M-3 as shown in the photograph.
The three-axis simulator was refurbished
and delivered to a leading manufacturer of inertial
navigation systems in the United States.
ACUTRONIC Refurbished Model 53M-3 Three Axis Motion Simulator.
4
The table will be used to calibrate and
test strap down Inertial Navigation
Systems (INS) that require performance
testing in controlled temperature
environments in the range of -85° C to
+85° C.
The instrumentation upgrade improved
the rate stability performance of each
axis by an average factor of 10 times
when compared to the original system
performance as presented in the rate
stability chart. The customer rate performance
goals were 0.05% stability
over 1 degree and 0.01% over 1 degree
throughout the entire rate range of the
table. As a minimum, on any axis at any
axis rate, the rate stability performance
was at least 0.0029%. This value was
more than 3 times better than the goal
specified by the customer. Typically, axis
rate stabilities were 0.001%, which is 50
times better than the customers’ specification.
The refurbishment included the
replacement of the obsolete MPACS
motion controller and the MACS drive
power amplifier instrumentation with the
“field proven” Acutrol ACT2000 Digital
Motion Control System and the ACU-
TRONIC PA2500 Drive Power Amplifiers.
An ACUTRONIC designed temperature
chamber control chassis was implemented
for precise control of the temperature
chamber. This temperature
control chassis used a dual-loop temperature
controller to provide improved temperature
regulation of the payload and
optimized ramp times.
The original drive motors on each axis
were replaced with higher torque AC
brushless drive motors to improve axis
accelerations and maximum axis velocities.
Brushless drive motor commutation
was processed within the Acutrol
controller. The original inner gimbal was

Axis 1 Positive Rates - Average Stability
Top Curve: Original Data with MPACS/MACS. Middle Curve: With
Acutrol. Bottom Curve: With Acutrol, Power Amplifiers, Motors, and
Acutrol Commutation (Rate Stability Improves by a Factor of 10).
Axis 1 Rate Stability Data over 1 Degree Intervall.
44 th International Paris Air
Show from 17 th to 24 th June
2001
The 2001 Paris Air Show
offered an unsurpassed opportunity
to display products, technologies
and services. The AC-
UTRONIC stand within the
Swiss Pavilion area attracted
visitors, customers and officials
with a live demonstration of a
Two Axis Motion Simulator and
a continuous video presentations
of ACUTRONIC key products.
A considerable amount of contact
papers were received with
very interesting application
notes.
Rate (deg//sec)
Rate Stability (%) vs Rate (deg/sec)
removed and replaced with a double
tabletop configuration and a temperature
chamber cooled with liquid nitrogen.
The temperature chamber was secured
to the middle gimbal and the tabletop
configuration was supported by an inner
axis shaft extension protruding through
As a summary, it can be stated
that the Paris Air Show fulfilled its
role as the most significant professional
international Exhibition.
International Aviation and
Space Salon MAKS 2001,
MOSCOW from 14 th to 19 th
August
ACUTRONIC attended the MAKS
2001 International Air and Space
Salon, Moscow for the second
time in cooperation with our Russian
Partner DAVIA / Aviapribor.
The stands of the Aviapribor
Company and the stands of a
number of other larger Russian
design- and production partners
were arranged within the domi-
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ACUTRONIC NEWSLETTER
the bottom wall in the chamber allowing
the double tabletop arrangement to
rotate inside the temperature chamber.
This new inner axis configuration significantly
reduced the inner axis inertia, but
also doubled the payload capacity for
the customer. Inner axis modifications
resulted in peak acceleration and velocity
performance that was at least two
times better than original system specifications.
The middle gimbal was dynamically
balanced to minimize variations
in inertia during simultaneous axis
rotations. Dynamic balancing also minimizes
the gyroscopic torque disturbances
between test table axes.
New slipring assemblies were installed
on each of the three axes. High capacity
power rings were implemented on the
outer and middle axes; this design consisted
of slipring assemblies that separated
all power circuits from the payload
slip ring circuits. The slipring upgrade
provided increased power capacity on
the power circuits to maximize slipring
reliability and provide isolation from the
customers’ payload slipring circuits.
In 2001 ACUTRONIC participated at main aerospace events
in order to expand and strengthen international customer relations.
By Reinhard Hoffmann, ACUTRONIC Germany
nant, individual Sukhoi Aircraft
Company pavilion. Beside an
operating Motion Simulator, the
current ACUTRONIC company
video was presented in sequence
with Aviapribor videos
on a large digital projector
screen.
This event was a central place
to discuss both the technology
with engineers and the business
with responsible, highly ranked
managers. It was realized that
many new projects are planned
where motion simulators are
necessary. Delegations from
Russian- and CIS-industry partners
and -customers visited the
combined stand in order to see
the presented material and to
get brief introductions

ACUTRONIC NEWSLETTER
Realization and Dissemination of
Mechanical Motion Quantities
The Metrological Application of the ACUTRONIC Model 170.01
by Dr. Christof Weissenborn, Physikalisch-Technische Bundesanstalt, Germany
The new multicomponent calibration system developed
and put into operation at PTB, will open
up new vistas for the identification of sensor characteristics
and the evaluation of mechanical structures.
The ‘rotational axis‘ is a custom single axis
rate table designed by ACUTRONIC to meet the
specific requirements of PTB.
Performance specification table
The Physikalisch-Technische Bundesanstalt
(PTB), Braunschweig and
Berlin, is the national metrological
institute (NMI) of natural and engineering
sciences and the highest technical
authority for metrology and physical
safety engineering of the Federal
Republic of Germany. Metrology,
understood as the “art of careful
measurement”, is as old as the history
of technology of mankind.
The manufacturers and users of transducers
and instruments for measuring
motion quantities are under increasing
pressure to establish and ensure
traceability to national standards. A
traceability system has been developed
at the NMI level based on primary
vibration calibration using laser
interferometry. Calibration includes the
three translational motion quantities,
acceleration, velocity and displacement,
and the three rotational motion
quantities, angular acceleration, angular
velocity and rotation angle.
max. angular acceleration >1000 rad/s 2
frequency range 0,1 Hz to >1000 Hz
max. angular rate ± 180 rad/s
max. torque 30 Nm
max. rate deviation ± 0,004 %
max. axis wobble error 0,33 arcsec
6
The multi-axis excitation system at
PTB consists of three linear electrodynamic
exciters, which are coupled by
hydrostatic bearings. The ACUTRON-
IC exciter, AC 170.01 provides a
(fourth) rotational degree of freedom
and is mounted on top of the three
axis table. Due to the combination of
translational and rotational motion a
wide variety of sensor testing can be

Motion Simulator
Model 170.01
Motion Simulator
Model 170.01 on
three linear electrodynamic
exciters
carried out, e.g. modelling the behaviour
of a gyroscopic yaw sensor used
in vehicles subject to the conditions of
real-world 3D environmental vibrations.
PTB specified the desired performance
very close to the limit of today’s
technology. Even so, the results of the
ACUTRONIC AC 170.01 are quite
outstanding.
The unique behaviour has been
achieved by means of extraordinary
effort: The precise motion is assured
by an air bearing, whose H-shape, with
a hollow shaft and two baffles, has a
high stiffness in both radial and axial
directions. On the control side, acceleration
feedback provides a third physical
quantity in addition to rotation angle
and rate for closed loop control. The
angular accelerometer Model 110-A of
ACUTRONIC delivers the essential
information for indicating the desired
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ACUTRONIC NEWSLETTER
mechanical motion of the table.
Moreover, the capability of external
control of the whole exciter by an iterative
control system adds a HWIL-feature
to the AC 170.
Currently, the table is equipped with
two specially invented miniature retroreflector
interferometers, which establish
the primary vibration calibration.
With this system, a new level of understanding
the many interrelated effects
compromising the mechanical input to
any inertial transducer is realized.
For further information, please contact:
Physikalisch-Technische
Bundesanstalt
Dr.-Ing. Christof Weissenborn
Fachlaboratorium 1.22
Beschleunigung
Bundesallee 100
38116 Braunschweig
phone: +49 531 592 1221
email: Christof.Weissenborn@ptb.de

ACUTRONIC NEWSLETTER
3D Motion Simulator for investigations
of the human balance system
Vestibulo-Oculomotor Laboratory, University Hospital Zurich
by Prof. Dr. med. Bernhard Hess, Department of Neurology, University of Zurich
A servo-controlled gimbal
system with three motorized
and two manually adjustable
axes, constructed by
ACUTRONIC Switzerland AG
(1999), allows static and
dynamic investigations of the
sensory organs that detect
our orientation and movement
in space.
On the research front, the
device is used to investigate
the psychophysics of spatial
orientation, the mechanisms of
the human balance system,
and the processing of visual
and vestibular information by
the central nervous system. In
addition, the 3D Motion Simulator
is also used to treat patients
suffering from certain disorders
of the balance system.
ACUTRONIC Schweiz AG
Techcenter Schwarz
8608 Bubikon, Switzerland
ACUTRONIC USA Inc.
139 Delta Drive
Pittsburg, PA 15238, USA
ACUTRONIC Deutschland GmbH
Bretonischer Ring 15
85630 Grasbrunn, Germany
ACUTRONIC R&D, USA
139 Delta Drive
Pittsburg, PA 15238, USA
Note:
A live demonstration of the
turntable can be found at
http: //web.unispital.ch/
neurologie/vest/
human_turntable.htm
phone (055) 253 23 23
telefax (055) 253 23 33
e-mail: office@acutronic.com
phone (412) 963 9400
telefax (412) 963 0816
e-mail: aus@acutronic.com
phone (089) 46 30 85
telefax (089) 46 46 77
e-mail: info@acutronic.de
phone (412) 963 9400
telefax (412) 963 0519
e-mail: ard@acutronic.com
ACUTRONIC – your long-term partner for system responsibility
Please visit our Home Page: www.acutronic.com
8
Impressum:
3D Motion
Simulator.
Editor:
Anne-Marie Crijns
ACUTRONIC Deutschland GmbH
Bretonischer Ring 15
D- 85630 Grasbrunn
phone: +49 89 46 30 85
email: alorbeer@acutronic.com
We would welcome your feedback
for improvement and new ideas.
Please feel free to contact our editor
Mrs. Anne-Marie Crijns
(former Anne-MArie Lorbeer).