Research On Life Prediction Method For The Momentum Wheel Based On Cyclic Stress Accelerated Degradation Test

Momentum Wheel is the key attitude control system of the satellite.With the enhancement of the aerospace manufacturing capacity,the reliability of the momentum wheel is greatly improved.Since the service life of the momentum wheel is greatly prolonged,it is often difficult to observe the failure in the experiment time.The momentum wheel has typical characteristics such as long life,high reliability and small test sample that the traditional life prediction method is difficult to apply.The space industry department designed and implemented a cyclic-stress accelerated degradation test carefully in order to simulate the complex operation condition of the momentum wheel.But at present,the research on this kind of test data is relatively small both in domestic and abroad.In this paper,the corresponding research on this problem is to be solved.The main contents of this paper include the following aspects.(1)A combination of qualitative and quantitative method to determine critical performance degradation.This paper introduced the structure and working principle of the momentum wheel,analyzed the stress and failure mechanism during its working,introduced the physical meaning of performance parameters and the relationship between it and failure.Through this series of qualitative analysis,the possible performance parameters were selected.Then the quantitative analysis of the data is performed to determine whether the performance parameters are suitable for the modeling of degradation.(2)Convert the composite condition to a single condition,and establish the degradation model.Cyclic-stress accelerated degradation test can simulate the momentum wheel in orbit composite condition better,thus it will get more real product life information.But it is very difficult to analyze the data obtained from composite operating condition directly.The stable condition and impacting condition are obtained by decomposing the composite condition.Then,the Wiener process degradation model is established.(3)Accelerating model of condition and impacting condition.Establish the model of the stable condition with speed amplitude and maximum speed,and the model of the impacting condition with speed amplitude and maximum speed,.(4)Based on the reliability model of series system,the life model of the momentum wheel is proposed,which consists of the stable working condition and impacting condition.