Design Of Micro-satellite Momentum Wheel

Momentum wheel can change the speed to achieve momentum exchange and storage.It is widely used in various kinds of space vehicles as a actuator of the attitude control system.Momentum wheels for micro-satellite must have the characteristics of small size,light weight,long life,high reliability,low power consumption and so on.Based on the characteristics of the micro-satellite momentum wheel,the structure is analyzed and designed.According to the electromechanical energy conversion in the momentum wheel,the electromagnetic relationship is analyzed in detail and then a control circuit is designed.In the end the finite element analysis and experimental study on the micro-satellite momentum wheel are carried out.The study mainly includes the following:(1)According to the integration design concept,the mechanical structure of the micro-satellite momentum wheel(including the bearing assembly,the wheel assembly,the motor component and the shell component)is designed.After the analysis of the main parameters from the aspects of material selection,manufacturing cost,product performance and so on,the basic size of the micro-satellite momentum wheel is determined.(2)The important parameters in the momentum wheel design process are modified after analyzing the inherent mode and the air gap flux density distribution of the motor component.And the electromagnetic torque of the momentum wheel is analyzed after the final dimension of the momentum wheel is determined.(3)Aiming at the problem that the commutation torque fluctuates greatly and the average torque decreases,a driving control circuit of microminiaturized momentum wheel is designed and a PWM modulation method for suppressing the torque pulsation of the high speed momentum wheel is proposed.(4)Accelerated life testing of bearings and armature windings were carried out.The mathematical model was established,and with the three parameter Weibull distribution,based on the failure mechanism of competition on the extraction of life data of momentum wheel with truncation method,using maximum likelihood estimation method for service life prediction of momentum wheel.