Gimbal Speed Control of SGCMG Driven by Ultrasonic Motor Based on Improved Active Disturbance Rejection Control

A hollow ultrasonic motor (USM) was employed as the gimbal actuator in a novel single-gimbal control moment gyroscope (SGCMG) configuration, capitalizing on its superior torque-density characteristics and zero-backlash operation. However, the gyroscopic dynamic disturbances and inherent nonlinearities of the HUSM present significant challenges for high-precision speed servo control. To address these issues, an active disturbance rejection control (ADRC) framework with enhanced compensation mechanisms was proposed for the gimbal servo system. Particular attention was given to resolving the fundamental trade-off between rapid response and overshoot suppression through the introduction of an adaptive damping factor that dynamically adjusts transient response characteristics. Furthermore, an output tracking differentiator with phase compensation was designed to mitigate output oscillations and measurement noise amplification. The control architecture parameters were optimized through comprehensive simulation studies incorporating HUSM's electromechanical coupling model. Experimental validation conducted on a 32-bit embedded microcontroller demonstrated: 1) speed tracking errors maintained below 0.05°/s across full operational range (0.1-300°/s); 2) closed-loop settling time under 20ms for step inputs of varying magnitudes; 3) remarkable disturbance attenuation achieving 92.4% suppression ratio at ultra-low speed (0.1°/s).