A practical measure of dynamic response of haptic devices

A method is described to characterize and experimentally measure the dynamic performance of haptic display devices. The method characterizes the response to impulse inputs of various frequencies characteristic of simulating hard contacts in virtual environments. By comparing the experimentally measured velocity just after the impulse with the actual velocity, a dimensionless measure of structural distortion is derived. The method is easy to apply because no additional sensors or test fixtures are required. This paper presents a derivation of the structural deformation ratio for the single degree of freedom case, generalization to N-DOF spatial devices, and experimental results for a single axis of a rugged haptic device in our laboratory