Tuned mass damper on spacecraft reaction wheel assembly

Abstract

Considering the wide frequency range and time-varying characteristics of reaction wheel assembly (RWA) micro-vibrations, an embedded tuned mass damper (TMD) was proposed herein to reduce the influence of the RWA micro-vibration effect on spacecraft. First, dynamics model of the RWA and a mechanical model of the angular contact ball bearing were constructed, and the time-varying characteristics of the RWA were theoretically analyzed. Based on single- and multiple-degree-of-freedom vibration absorption dynamics models, it was shown that the TMD could be applied to the vibration suppression of the RWA’s multi-modal and time-varying state by changing the design parameters of the TMD. Based on the RWA single-degree-of-freedom equivalent dynamics model, the effects of the TMD natural frequency and damping on the displacement amplitude ratio of the RWA were analyzed, and the sensitivities of the RWA resonance peak amplitude and resonance frequency to the two parameters were analyzed by the Sobol sensitivity analysis method. Then, according to the analysis results, the structural design of the TMD in the RWA was guided, and a test platform was built to obtain the RWA micro-vibration data. Finally, a normalized amplitude-frequency response identification algorithm was used to eliminate the effects of non-linearities in the experimental data and to identify the RWA dynamics in a time-varying state, thus obtaining the RWA amplitude–frequency response curve and verifying the results of the theoretical analysis. Theoretical and experimental data showed that the addition of a TMD structure with variable damping and stiffness within the RWA allowed for micro-vibration suppression for arbitrary modes and improved the RWA vibration characteristics. This could provide convenience for different specifications of RWA vibration suppression as well as reference for further research on the effective application of TMDs in RWAs.