Modelling of gimbal control moment gyro and analysis of gimbal disturbance impact

Control Moment Gyroscope is one of the main sources of disturbance affecting the accuracy of attitude control system in the spacecraft. This paper concentrates on analysing and testing the micro-vibrations produced by CMG. To analyse its disturbance features systematically, the mechanical features of flywheel, frame and the entire CMG will be firstly studied, and then the kinetics model of CMG will be established. The structure patterns of disturbance sources, including mass imbalance and bearings irregularity, are taken into account in this model. Thirdly, the micro-vibration dynamic testing of CMG would be implemented by using originally designed eight-axial test board, including dynamic tests under multiple frame rotation speed. Finally, comparison will be demonstrated between the measured disturbance features from the experiment and the calculated theoretical model results to validate the model. Therefore, the model presented here can be employed to predict the micro-vibration characteristics of a CMG.