Robust independent joint controller design for industrial robot manipulators

A novel approach is presented for the design of simple robust independent joint controllers for industrial robot manipulators. In this approach, each joint actuator is treated as a simple inertial system plus a disturbance torque representing all the unmodeled dynamics. By a very simple algorithm, the disturbance is instantly estimated and rejected, thus allowing a simple proportional-derivative (PD) control scheme to be used. The stability of the proposed control law is analyzed. Experimental evaluations of the controller on a microcomputer-controlled PUMA 560 arm were performed. It is shown that the control scheme is simple and practical and that it can be easily implemented on an industrial manipulator presently in use