The Reliability Analysis Of Spacecraft Vibration Test Sliding Bench System

In recent years, with the rapid development of national economy, the spacecraft is becoming more and more diversified. In order to adapt to the high efficiency, high quality and high reliability of production process, the spacecraft products are very necessary to carry on dynamic environmental test on the ground so as to ensure that they operate reliably in space. According to Chinese space technology development,400kN vibration test sliding bench system, introduced in 1997, is a significant large scale equipment of spacecraft dynamic environmental test. Vibration test equipment has been running for more than ten years, and some of its components have aging and failures. The problems influence the research and manufacturing of spacecraft, so that it is extremely necessary and significant to make research on sliding bench’s reliability.For spacecraft vibration test sliding bench, the study starts globally with the reliability assessment of its subsystem, then focuses locally on the hydrostatic bearing’s reliability analysis based on the vibration signal. The main contents of the paper include:(1) For the subsystem-horizontal slide’s historical failures and reliability problems, FMEA method is applied to make the overall qualitative analysis, so that the weakest link could be positioned. In view of the reliability series model of horizontal bench, it is concluded that the model is conformed to weak correlation boundaries theory by analyzing and determining. Compared with the reliability prediction value which is calculated via completely independent conventional reliability formula and weak correlation, the theory is more appropriate to deal with the actual situation. It is more effective for reliability assessment of horizontal sliding bench. This method can qualitatively analyze and quantitatively calculate the horizontal slide system from the global perspective.(2) After collecting hydrostatic bearing vibration signal of sliding bench, first of all, FFT is used to analyze the signal frequency and time domain diagram to acquire basic information. Meanwhile, classical smoothing method and wavelet packet denoising are utilized to process time domain signal respectively, by comparing which can be seen the wavelet packet denoises fast and flexibly, and accurately. Then extracting fault feature in time domain indices (peak and root mean square) after wavelet packet de-noising, it lays foundation for feature indicators binding weibull proportional hazards model.(3) In view of the wear problem of liquid hydrostatic bearing in the subsystem-vertical sliding bench, sensitive feature indicators including peak and root mean square are combined with weibull proportional fault rate model to reflect the hydrostatic bearings’operation states by referring to the reliability evaluation method of rolling bearings’vibration condition monitoring. By comparing with historical faults of hydrostatic bearings, it is concluded that the rationality of current equipment reliability assessment and preventive maintenance. Finally, the maintenance of hydrostatic bearing is proposed according to the condition-based maintenance.