full Paper - Nguyen Dang Binh

EUROGRAPHICS 2005 Tutorial
Abstract
Haptic Interfaces
Massimo Bergamasco, Carlo Alberto Avizzano
PERCRO
Scuola Superiore S.Anna
Pisa, Italy
The analysis of the behaviour of the human operator during the interaction with Virtual Environments requires the
availability of adequate interface systems. In particular, when the control of manipulative and explorative procedures
is required, all the movements of the hand should be recorded and tactile as well as contact force stimuli
should be replicated at the level of the hand. In this paper we address the aspects related to the development of
force feedback systems devoted to generate such stimuli with the aim to allow the human operator to obtain a
realistic control of the operation. The peculiar roles of force feedback systems will be presented with direct reference
to the grasping and explorative tasks. The general functionalities of force feedback systems are highlighted
together with the description of the Haptic interfaces systems developed at the Scuola Superiore S.Anna. Tactile
feedback is presented by considering the modelling of both thermal and indentation stimuli.
1. Introduction
In a paper of 1990, S. Lederman and R. Klatzky [1] considered
procedures of haptic exploration of objects performed
by the human “observer” with the aim of apprehension and
recognition of object features. In the same paper Haptics was
defined as “a perceptual system that uses both cutaneous (including
thermal) and kinesthetic inputs to derive information
about objects, their properties, and their spatial layout” [1]
[2]. Lederman and Klatzky, by referring to the work made
by J.J. Gibson in 1962 [3], clarify the importance of “the
purposive aspect of haptics” in terms of the acquisition of
information related to object’s features with respect to the
sensation resulting from passive stimulation of the skin performed
by external means or devices. The same paper highlighted
the correlation between the typical hand movement
pattern related to a specific exploratory procedure and the
particular object knowledge associated during the execution
of the procedure [1]. Our interest in that paper was referred
to the implications on the control of manipulative procedures
during teleoperation where a human operator is asked to control
movements and forces exerted on objects by a remote
robotic system. The introduction of the concepts of telepresence
and virtual presence stresses once more the importance
of the capability for the human operator to extract realistic
information about the features of the object remotely
c­ The Eurographics Association 2005.
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or virtually manipulated [4]. Conceptually, the rendering to
the human operator of the sensation of a physical interaction
with a remote or virtual environment can be achieved by
utilizing appropriate interface systems capable of generating
adequate sensory stimuli to the operator. However the stimulation
should be performed by leaving the human operator
to execute the task according to a natural, realistic procedure.
In this way the movement patterns, in particular of the
arms and hands, should be maintained as close as possible to
those associated to a real exploratory procedure. Coherency
between the purposive aspect of the task, performed by the
human operator with the intent to acquire information about
a specific object’s feature, and the operator’s hand movements
should be the key for haptic perception also in the
case the object is remotely located or virtually represented.
The possibility for the human operator to execute realistic
movements and, at the same time, to achieve adequate sensory
stimuli is then a fundamental requisite for achieving
a satisfactory control of the operation. Realism of interaction,
especially for haptic perception tasks, is then strictly
related to the capabilities of the interface system to allow
natural movements to the human operator’s hands as well as
to the fidelity in reproducing adequate stimuli on them. As
it comes out from the definition of Haptics given above, the
basis for haptic perception is represented by cutaneous and