Disturbance Observer Compensation Based on Sliding-Mode Approach for Solving Compliant Actuator Tracking Control Problems

The rehabilitation robot needs directly physical interaction in the process of rehabilitation training for patients. Considering the safety of patients, the actuator of the rehabilitation robot should have the advantages of flexibility. Based on the requires of rehabilitation robots, an accurate dynamics model is considered the interaction force between the parts of the compliant actuator, which is established, and the control scheme of the compliant actuator end trajectory tracking is designed. The disturbance observer is designed to estimate the disturbance value and actively eliminate the influence of some disturbances on the compliant actuator. A nonlinear sliding mode controller is designed to reduce the tracking error and shaking the compliant actuator. Through the simulation experiments, compared with the traditional proportional-integral-derivative (PID) controller, it is obvious that the tracking effect of sliding mode control is more efficient on the basis of using the disturbance observer to dispose the disturbance.