Limited Amplitude-Disturbance Observer Control for Backlash-Containing Electromechanical System

This article presents a limited amplitude-disturbance observer (LADOB) as a means to counteract transient disturbance dynamics in a nonlinear control system with backlash. The core principle of this method involves directly constraining the linear output amplitude of the observer using a saturation function. This approach yields a high-bandwidth disturbance observer while ensuring the stability. By virtue of its rapid response, the LADOB effectively mitigates backlash spikes induced by speed reversal. Additionally, the saturation function within the LADOB control system addresses limit cycle oscillations stemming from backlash dynamics. An investigation is conducted to determine the optimal balance between stability and antidisturbance performance by examining the relationship between the saturation threshold and the system's bandwidth. Experimental validation is carried out on a belt-drive turntable, effectively demonstrating the efficacy of the proposed method in attenuating nonlinear backlash.