Design for flexible joint controller based on a new compensation control strategy

For the uncertain disturbance, friction and parameter variation, modeling errors and other issues in flexible joint robot control system, conventional PID control can not take into account both the requirements of stability and control accuracy. To solve this problem, a novel robust joint controller based on a new compensation control strategy is designed. In the controller design, the friction is divided into two parts, linear and nonlinear, and the disturbance into certain and uncertain. The part associated with the robot self structure, deterministic disturbance and the linear part of the friction can be controlled effectively by the feedforward compensation part. Feedback compensation part of the proposed controller can compensate nonlinear part of friction, system parameter variation, external uncertain disturbance, modeling error and so on. Its stability is completely proved by Lyapunov stability theory. Finally, the results on the platform of HIT 4-DOF flexible manipulator show that the controller has good position tracking performance and robustness.