Abstract: Control moment gyroscope（CMG）is an actuator which plays an important role in agile attitude maneuvering and in steadily attitude maintaining of spacecraft. In order to recognize the microvibration characteristics variation of the CMG subjected to mechanical tests, the acceleration responses and forcemoment responses are measured via accelerometers and multicomponent dynamometer respectively, when the CMG is operating. Then, statistical analysis in time domain and FFT analysis in frequency domain are implemented. The results show that the components of ball passage frequencies and those multiples, which are caused by the eccentricity and point defects of bearings, dominate the acceleration responses, but they are all over 300 Hz. However, the component of nominal frequency of rotor spin still dominates when acceleration responses are converted into displacement responses, which is also confirmed by forcemoment responses. The microvibration of the CMG subjected to mechanical tests becomes worse, which mainly results from the augmentation of the static and dynamic imbalances, from the augmentation of the eccentricity of bearings, and from the damage to bearings. Furthermore, the microvibration amplitude can be also impacted by the dynamic coupling between rotor speeds and structure modes.

Key words: control moment gyroscope, bearing, microvibration, mechanical test