Control design for robust performance of a direct-drive robot

An experimental approach to achieve robust performance of direct-drive robot motion control is presented in this paper. It consists of: (i) decoupling the robot dynamics via feedback linearisation; (ii) frequency domain identification of the decoupled dynamics; (iii) compensation of these decoupled dynamics using feedback controllers designed via /spl mu/-synthesis. The designed controllers ensure robust performance, i.e., guaranteed accuracy of robot motions despite uncertainty in its dynamics and disturbances affecting the robot operation. Theoretical aspects of the control design are formulated. Its practical implementation on a direct-drive robotic arm is demonstrated in detail. Experimental investigation confirms the quality of the design: specifications on performance and robustness are practically realized.