Trajectory tracking control of articulated robot arm with sensory feedback: laser beam tracking system

Abstract

A control scheme for a computer controlled articulated robot arm with sensory feedback is described. A general control algorithm for such a problem is presented. In order to implement sensory feedback effectively, the dynamics of a robot arm are described in the task coordinate system, which is selected appropriately for the sensory feedback. Then the dynamics of a robot arm in the task coordinate system are linearized using nonlinear feedback. In general, the linearization cannot be done completely because of variations and errors of physical parameters of a robot arm. A robust controller is designed for this linearized robot arm so that the effect of parameter variations and errors can be lessened. The control law is simplified by the use of high gain feedback. The simplification makes the implementation of the control law very easy. The proposed method is applied to the trajectory tracking control of an articulated robot arm using a laser beam, which indicates the reference trajectory. The experimental results are satisfactory, and show the validity of the proposed control algorithm.