Abstract: In view of the problem of low-frequency resonance point existing in the double gimbal magnetically suspended control moment gyro (DGMSCMG) system with harmonic drive, a vibration suppression control method based on the extended state observer (ESO) is presented. Third-order ESOs are separately designed at the input side and the output side of the harmonic drive. Not only the angular rate of motor and load, but also the non-linear variation of torsional stiffness and integrated disturbance deduced from outer disturbance moment can be estimated accurately by the angular position signal of the motor and load side. The integrated disturbance can be suppressed by feed-back and feed-forward compensation. The new controller suppresses the vibration of gimbal servo system and improves angular precision of the gimbal. Simulation and experimental results show the control algorithm proposed in this article is feasible and has strong robustness.

Key words: DGMSCMG, extended state observer, combined disturbance, harmonic drive, stiffness