High bandwidth force regulation and inertia reduction using a macro/micro manipulator system

A robot´s ability to maintain desired interface forces during constrained motion is governed by its driving-point impedance and primarily by its inertia. Negative force feedback is a means of reducing this driving-point impedance, but the system becomes unstable at high bandwidths. A macro/micro manipulator system, consisting of a large (macro) robot carrying a small (micro) high-performance robot, alleviates this problem by physically reducing the endpoint inertia as well as providing an inherently stable physical configuration for high bandwidth force control. A robust controller design based on physical equivalence and impedance matching is proposed. It is shown that interface force regulation at bandwidths higher than the structural frequencies of the macromanipulator can be achieved with only minimal knowledge of the structure