Motion and force control of robot manipulators

In this paper we present a unified approach for the control of manipulator motions and active forces based on the operational space formulation. The end-effector dynamic model is used in the development of a control system in which the generalized operational space end-effector forces are selected as the command vector. This formulation provides a framework for natural and efficient integration of both end-effector force and motion control. A "generalized position and force specification matrix" is used for the specification of tasks that involve simultaneous motion and force operations. Flexibility in the force sensor, end-effector, and environment, and problems related to impact are discussed. The real-time operational space control system, COSMOS, has been recently implemented in the NYMPH multiprocessor system. Results of experiments involving contact and force step input response are presented.