Event-based haptics and acceleration matching: portraying and assessing the realism of contact

Contact in a typical haptic environment resembles the experience of tapping on soft foam, rather than on a hard object. Event-based, high-frequency transient forces must be superimposed with traditional proportional feedback to provide realistic haptic cues at impact. We have developed a new method for matching the accelerations experienced during real contact, inverting a dynamic model of the device to compute appropriate force feedback transients. We evaluated this haptic rendering paradigm by conducting a study in which users blindly rated the realism of tapping on a variety of virtually rendered surfaces as well as on three real objects. Event-based feedback significantly increased the realism of the virtual surfaces, and the acceleration matching strategy was rated similarly to a sample of real wood on a foam substrate. This work provides a new avenue for achieving realism of contact in haptic interactions.