Disturbance rejection control for uncertain systems with actuator saturation

Abstract

To address the issue that conventional disturbance observer(DO)design did not consider actuator saturation, which is prevalent in practical systems, a DO-based control(DOBC)strategy with anti-windup compensation is proposed. First, the reason of windup phenomenon in the conventional DOBC when the actuator is saturated is studied. Then, an anti-windup compensator is designed by minimizing the performance index, and patched to the DO so that the modified DOBC can effectively handle actuator saturation. Finally, local asymptotic stability analysis is performed on the resulting closed-loop systems. Comparative simulation results show that when there is actuator saturation, the proposed method has smaller errors in position tracking and disturbance estimation, and the designed compensator can maintain the DO states to be as close as possible to those without actuator saturation. This verifies that the proposed method is superior in anti-disturbance and anti-windup.

Keywords

anti-windup / disturbance observer / dynamic compensator / actuator saturation