PID control of robot manipulators in task space

This paper addresses the position control of robot manipulators in general task space with a model-free controller. A simple proportional-integral-derivative (PID) control is developed. The closed-loop system formed by the proposed PID control and the robot system is shown to be global asymptotically stable. Conditions on controller gains ensuring global asymptotic stability are obtained herein in a form of simple inequalities including some well-known bounds extracted from robot dynamics. Advantage of the proposed control includes the absence of model parameters in the control law formulation and thus permits easy implementation. Simulations are presented to illustrate the effectiveness of the proposed approach.