Velocity-Tracking Control Based on Refined Disturbance Observer for Gimbal Servo System with Multiple Disturbances

Multiple disturbances are the main constraints that hinder the high-performance velocity tracking of the gimbal servo system in CMG. This paper presents a non-cascade structured velocity-tracking controller (NCVTC) based on a refined disturbance observer (RDO) for handling multiple disturbances and improve the tracking performance. Specifically, a disturbance observer (DO) is designed to estimate the imbalance disturbance which can be represented by an exogenous system. The disturbances that cannot be modeled a priori are treated as a lumped term and estimated via extended state observer (ESO). By resorting to disturbance estimation, a novel sliding mode controller (SMC) based on the disturbance estimation values is developed to handle the mismatched problem and chattering issue. Finally, experimental tests are conducted to verify the effectiveness of the proposed anti-disturbance control scheme.