Analysis, Estimation, and Rejection of Multi-Frequency Unknown Disturbances in CMG Gimbal Servo Systems

This brief aims to deal with the CMG gimbal servo system's velocity tracking problem in the presence of multi-frequency unknown disturbances. To fully comprehend the gimbal servo system, closed-loop uncertainty quantification is first employed. Second, an adaptive refined disturbance observer built on a second-order generalized integrator-frequency locked loop is designed to accurately separate and estimate multiple disturbances in the absence of precise frequency information. Subsequently, the PI controller is integrated to achieve multi-frequency unknown disturbances suppression and compensation. Finally, experimental results demonstrate the effectiveness of this method under multi-frequency unknown disturbances.