Application of Complementary Sliding Mode Control with State Observer in Servo System of Voice Coil Motor

Abstract

Due to the vulnerability of the voice coil motor (VCM) servo system to uncertain elements such as external disturbance, nonlinear friction, and inherent end impact, a dynamic model of the linear servo motor motion system with uncertainty is constructed. The complementary sliding mode variable structure controller (CSMC) is built on the basis of the standard sliding mode control by merging the generalized sliding mode surface with the complimentary sliding mode surface. Theoretical study demonstrates that this controller can ensure the system's tracking error converges, suppresses uncertain factors, increases the system's transient reaction speed, and successfully reduces tracking error. Simultaneously, the saturation function is chosen as the switching function, which mitigates the sliding mode control chattering problem. The total interference is defined as the unmeasured and unknown interference in the mathematical model of the system. The system's position and total disturbance are estimated using the nonlinear extended state observer (ESO). The estimated total disturbance is then feed-forward corrected to the control loop. As a result, a nonlinear extended state observer-based closed-loop complementary sliding mode position control technique is developed. Finally, the system experiment demonstrates the effectiveness and feasibility of the suggested control approach. The complimentary sliding mode control system with state observer offers a high degree of tracking accuracy and robustness, which considerably minimizes the system's tracking error.