In this paper the first haptic display capable of applying a true
impulse to the operator is presented. The applied impulse results in
an immediate change of the user's momentum. Such a change is considered
to be invaluable in making interactions with rigid virtual objects feel realistic.
Conventional methods can only approximate impulses by outputting a constant
force over a certain number of sample periods. The quality of these impulses
is therefore limited by the maximum torque of the motor. At high interaction
velocities these methods loose realism. The usage of large motors not only
brings along safety issues, it also compromises the feeling of free motion.
The new haptic display can generate an arbitrarily large impulse by continuously adapting the amount of momentum of a momentum wheel. At the predicted instant of contact with the virtual object, an electromagnetic tooth-clutch is engaged. The momentum wheel is mechanically connected to the handle of the haptic display and a real, but controlled, collision between operator and momentum wheel is realized.
The impulse generation part of the device is in fact the first `generalized
encountered haptic display'. Like typical encountered haptic displays its
influence is not felt in free motion, but in contrast to them it is not limited to only static encounters, but effectively applicable to make encounters over a full velocity spectrum.
22th RSJ Best Paper Award in 2008.