Ultra-low speed control strategy for SGCMG gimbal servo system

Ultra-low speed control strategy is a difficult problem in the single gimbal control moment gyro (SGCMG) gimbal servo system. Speed detection resolution and disturbance torque attenuation are two major factors that restrict further improvements on the ultra-low speed control performance. In this paper, a novel ultra-low speed control strategy is proposed, including a multi-cycle backward difference combined with KALMAN estimation speed detection method to increase the ultra-low speed detection resolution, and a variable structure controller (VSC) combined with repetitive controller (RC) to improve the disturbance torque attenuation capability. Simulation results show that the ultra-low speed control strategy is feasible and efficient. Comparing to the conventional controller, the speed control precision increases almost by one order of magnitude.