Adaptive Nonlinear Compensation for a SCARA Robot with Flexible Joints.

Abstract

Nonlinear dynamic compensation, which is derived from inverse dynamics, is very useful for controlling robot manipulators. An accurate modeling of the robot system and a precise estimation of the physical parameters, however, are necessary in order to get enough control performance with that method. In this paper, on the mathematical model of robot manipulator with PD controller, the stiffness of the transmission system between motor and robot arm is taken into consideration. Furthermore, the controller parameters are adjusted only by using actual motor angles and reference robot arm angles. The effectiveness of this method is examined by an experiment using an industrial SCARA robot. The result proves that this method provides satisfactory performance for a reduction of both residual vibration and tracking errors.