ANALYSING AND SUPPRESSING THE MICROVIBRATION OF MOMENTUM WHEEL ASSEMBLIES IN SPACECRAFTS

Momentum Wheel Assemblies (MWAs) have been widely used in spacecraft attitude control. Microvibration disturbances from rotating MWAs affect spacecrafts pointing jitter and have the potential to generate microphones in payload instruments. Understanding and suppressing the microvibration of MWAs is a crucial factor to achieve the desired level of payload performance. In this paper, a dynamic model is proposed and the spectral microvibration measurements are carried out to analyse the microvibration signature of a MWA. A finite element model is established to capture the modes of the rotating rotor system for better revealing the structural dynamics of the MWA. Based on the microvibration signature of a MWA, the control of the typical disturbance sources in MWAs have been carried out instead of an isolator equipped between a MWA and the precision payloads. As MWAs are commonly used in a wide range of speeds, a multi-speed dynamic balancing method for the rotor system is proposed firstly, and the selection of the balancing speeds and proceeding of this method are discussed. Moreover, a novel damper by the use of a constrained layer damping and flexible vibration absorber has been designed to suppress the vibration of the rotating wheel. Finally, the disturbing force test of a MWA’s rotor system is conducted to verify the effectiveness of the vibration control. Through comparison, the disturbing force degradation rates of the root mean square in the frequency domain of 0~300Hz are more than 1.1dB and 3.9dB separately by the use of multi-speed dynamic balancing method on a rotor system and a novel damper on a wheel. The method would be helpful for MWAs and other rotor systems.