Game Development Reference
10.4.2.1 Tactile interfaces for teleoperation and telepresence
Teleoperation and telepresence arouse special interest in terms of portability of the
interface, transparency as well as diversity of the potential applications in this domain
(Kheddar, 2002). This sectionwill present a few tactile rendering interfaces designed for
teleoperation and telepresence applications that use different actuation technologies.
Exos developed a device for rendering of the sliding and shearing sensations
(Chen &Marcus, 1994). A sliding rendering with one degree of freedom was designed
to reproduce the sensations of loss of adherence and lateral stretching on the skin. The
interface is attached to the finger when it is used. The maximum attainable speed in
rotation is 0.0254m/s. The normal force can reach 17.8N.
Another interface offered by Exos is the TouchMaster. This is a tactile interface that
helps to stimulate all the fingertips of the hand. The actuators are Voice Coils (electro-
magnetic actuation). These actuators provide a vibrotactile feedback that can be used
to represent information regarding contact between the fingertips and the manipulated
objects. The standard configuration provides a frequency range of approx. 210-240Hz
and a variable amplitude.
For a teleoperation application and as part of a collaboration between the Uni-
versity of Ottawa and the Canadian Space Agency, the authors in (Petriu & McMath,
1992), describe a dual device of tactile actuators and sensors. The tactile stimulator is
composed of 8
8 electromagnetic vibration needles on an area of 6.5 cm 2 .
In the Armstrong laboratory, Chris Hasser studied the possibility of using tac-
tile feedback in robotic teleoperation and in VE applications (Hasser & Wesenberger,
1993). One of these studies consisted of evaluating the perception characteristics on
a tactile surface of 5
6 actuators, with a space of 3mm between them. This inter-
face had shape memory alloy wire-based actuators, used to mount and dismount the
tactile elements (contactors). This made it possible for the team to present a tactile
interface (matrix) under the name HAP-TAC (Haptic Tactile) which was used in the
TacGraph system 4 to provide a data tracing rendering to blind persons. The behaviour
in closed loop groups the performances required for a tactile application with a max-
imum actuation force value of 2N and a precision of less than 0.12N (Hasser &
A tactile glove, the “Teletact'', which provides pressure and temperature render-
ing, has been developed by researchers of the University of Salford, in the electronics
department. The interface is composed of lead zirconate titanate ceramic disk actuators
with a diameter of 10mm and thickness of 1mm. In another version the pressure or
contact forces are provided by flexible pneumatic tanks that are actuated by separate
pneumatic power elements, connected to the glove by means of valves and pipes. The
tactile feedback is transmitted to thirty different locations on the surface of the fingers
and the palm of a hand with force amplitudes that can reach 60N.
The ARRL (Advanced Robotics Research Ltd. Salford) handle was developed by
the same Salford team that developed Teletact I and II.
It incorporates three air pockets (the same pneumatic principle as Teletact), in
order to reproduce simple tactile renderings when the hand or the virtual cursor of the
operator comes in contact with a virtual object. In a special version of this interface,
4 TagGraph: a computer tool that helps to build tactile graphic scenes.