Improving Dynamic Response of AMB Systems in Control Moment Gyros Based on a Modified Integral Feedforward Method

During gimbal maneuvering, the dynamic characteristics of the active magnetic bearing (AMB) rotor system is an important concern for the applications of the magnetically suspended double-gimbal control moment gyro (MSDGCMG). Both the static torques caused by the gimbal motions and the dynamic torques by the rotor twisting motion will have an impact on the dynamic performance of the magnetically suspended high-speed rotor. This paper explores a modified current integral feedforward (CIF) control scheme to improve its dynamic response. Using a dynamic regulator, the CIF method is applied to supply the static torque by the permanent magnets and simultaneously improve the stability margin of the AMB rotor system. Then, the multiple compensation method is proposed to compensate the dynamic torque to further improve the response speed. The influence of rotor tilting on the output torque precision of MSDGCMG is also analyzed. Finally, the experimental results on a developed MSDGCMG prototype validate the effectiveness of the proposed method. The modified CIF combined with dynamic torque compensation resulted in a step response settling time of 0.13 s as compared with the traditional method with a settling time of 2.5 s.