CASE-STUDY ON HAPTIC DEVICES - HUMAN-INDUCED INSTABILITY IN POWERED HAND CONTROLLERS

This article describes the dynamic behavior of a hand controller when it is maneuvered by a human. A general control architecture is develop ed that guarantees various impedance's on the hand controller. We show that some compliancy either in the hand controller or in the human ar m is necessary to achieve stability of the hand controller and the hum an arm taken as a whole. The actuators' backdrivability, the dynamics of the hand controller mechanisms, and the computer sampling time are discussed as they relate to system stability. A set of experiments tha t mere performed on a prototype hand controller are presented to show the system performance.