Composite controller design for PMSM direct drive SGCMG gimbal servo system

Comparing with the indirect drive gimbal servo system of single gimbal control moment gyroscope (SGCMG), direct drive gimbal servo system based on permanent magnet synchronous motor (PMSM) can achieve higher precision and faster response. However, the difficulty of PMSM controller design increases, because PMSM has to endure larger multi-source and multi-band disturbances due to the lack of a decelerator. In this paper, PMSM direct drive system is described, importantly, based on SVPWM control strategy, a novel composite control strategy is proposed: an adaptive nonsingular terminal sliding mode controller (ANTSMC) with a disturbance sliding mode observer (SMO) is designed to achieve high precision speed closed-loop control and compensate uncertain large low frequency disturbances; a repetitive controller (RC) is designed to compensate high frequency disturbances. Simulation results show that the proposed controller has strong robustness and disturbance tolerance, and can achieve high precision and fast response control performances.