Rotational Excitation Dynamical Model and Micro-vibration Characteristics of Momentum Wheel

Abstract

The momentum wheel is a critical component of high-precision stable platform of the spacecraft. During the working process, with the continuous improvement of satellite performances such as attitude stability and imaging precision, the influence of micro-vibration on the control accuracy of the momentum wheel becomes increasingly prominent. In order to improve the attitude control accuracy of the spacecraft, it is necessary to suppress the disturbance force (moment) from momentum wheel. Based on the structural and mechanical characteristics of the components, the rotational excitation dynamical model of the momentum wheel is established, and the vibration sources of micro-vibrations are obtained. Hereby a finite element model of the momentum wheel with structural and excitation characteristics will also be established. Combined with the test of modal vibration characteristics and the waterfall diagram of the ascent, the results show that the non-uniform and non-continuity of wheel body is the main reason for the low-order traveling-wave vibration of the momentum wheel during operation; the asymmetry of the strut structure and the bearing support structure leads to the harmonic excitation vibration.KeywordsMomentum wheelMicro-vibrationNon-uniformityTraveling wave vibrationHarmonic-wave excitation