Game Development Reference
Florian Gosselin and Claude Andriot
Contributor: Philippe Fuchs
The progress made in the field of information technology helps to create virtual worlds
that are becoming more and more real, where the user can not only see, hear and feel
the surrounding objects but can also touch them, thanks to haptic interfaces.
In reality, haptic interfaces include twomain types, i.e. the force feedback interfaces
or kinaesthetic interfaces and tactile feedback interfaces. The kinaesthetic sense helps
to feel the position and the movements of the body as well as the forces exerted on
it using proprioceptive sensors located in the muscles and tendons. The tactile sense
helps to feel the shape, texture and temperature of the objects using various types of
sensors located at the level of the skin.
We shall only deal with force feedback interfaces in this chapter. Their purpose
is to measure the movements of the user and apply feedback forces according to the
interactions in the virtual world.
8.2 PROBLEMS AND CLASSIFICATION OF FORCE FEEDBACK
The first works on force feedback were carried out in the nuclear industry, in the mid-
dle of the 50's. In order to handle radioactive products without putting the operator's
life at risk, engineers developed the concept of the master-slave system that helps to
control a remote slave robot using a master arm. The quality of the system depends
on its transparency, a term used to convey the absence of distortion of the informa-
tion regarding the position and force between the master and slave, i.e. between the
operator and environment. Ideally, the operator must feel like he is working in direct
contact with the remote environment. The first master-slave systems were completely
passive and were connected using cables and pulleys. In the 60's, the progress made in
electronics and automation has made it possible to separate the master and slave arms
by motorising them and by replacing the mechanical coupling with an analogue cou-
pling, followed by a digital one. In the 80's, the advances in IT and Robotics helped to
work using Cartesian coordinates in the space of the task. We have since been able to
develop master and slave arms with a different structure (the master arm and slave arm
are more adapted to the abilities of the user and the task to be carried out respectively).