Game Development Reference
Figure 8.18 Haptic Gear. (Illustration: Hirose Lab, University of Tokyo, with permission)
freedom with force feedback is fixed on the forearm of the user. It weighs 500 g and
the force feedback is approx. 2N, which is relatively limited.
The generic portable interfaces can also use a tight rope architecture whose struc-
ture is very light. This is the case of Haptic Gear developed by the University of Tokyo
(Hirose et al., 2001). This interface is composed of a base fixed on the back of the user
integrating 4 motor units connected to the hand-held pen by 4 tight ropes (Figure 8.18).
Its total weight is 2.4 kg and its force capacity is approx. 16N. However, this force
can only be generated towards the back as all the motor units have been placed at the
back of the pen to limit visual intrusion.
In addition, any force applied on the pen is accompanied by an equivalent force
applied by the base of the robot on the back of the user.
The induced disturbance is however limited because the back is not a very sensitive
area of the human body. A comparable interface has been developed in Italy by the
LAR-DEIS (Laboratory of Automation and Robotics) laboratory of the University of
220.127.116.11 Portable interfaces for hand
Several portable interfaces have been specifically developed for manual interactions.
The IKD interface developed by CEA-LIST under the European project MUVII is
very typical of this type of robots (Gosselin et al., 2005a). It consists of 2 robots
with 3 degrees of freedom with force feedback fixed on a common base connected
to the user's hand (Figure 8.19), which provides a force feedback at the fingertips
in all directions. Tactile robot actuators with 2 degrees of freedom provided by the
Computouch company are integrated at the end of the 2 robots under the fleshy part
of the fingers, to enhance the haptic information transmitted to the user.
An optical 6D tracker target is fixed on the base of the interface to track the hand
movements in space. This interface, meant for educational applications, provides a
very intuitive and smooth handling of virtual objects with two fingers (thumb and