Dynamic sliding mode control for ball screw drive systems under a disturbance observer scheme

This paper studies disturbance-observer-based dynamic sliding mode controller design for trajectory tracking control of ball screw drive systems with matched and mismatched disturbances. Specifically, a unified observer is constructed to estimate the state and disturbance of the ball screw drive system simultaneously. Then, a novel sliding surface is constructed based on the tracking error, the disturbance observer, and the reference trajectory, where the tracking error is defined according to state observer and reference trajectory, and the disturbance observer and reference trajectory are, respectively, introduced for disturbance attenuation and tracking error reduction. Further, a dynamic sliding mode controller is synthesized to drive the tracking error, i.e., the linear trajectory error and rotational trajectory error, onto the sliding surface in a finite time. It is shown that the proposed dynamic sliding mode control suppresses not only matched but also mismatched disturbances. Finally, the effectiveness of the presented control strategy is verified through experimental studies.