Useful life prediction using a stochastic hybrid automata model for an ACS multi-gyro subsystem

摘要

A useful life prediction method based on the integration of the stochastic hybrid automata (SHA) model and the frame of the dynamic fault tree (DFT) is proposed. The SHA model can incorporate the orbit environment, work modes, system configuration, dynamic probabilities and degeneration of components, as well as spacecraft dynamics and kinematics. By introducing the frame of DFT, the system is classified into several layers, and the problem of state combination explosion is artfully overcome. An improved dynamic reliability model (DRM) based on the Nelson hypothesis is investigated to improve the defect of cumulative failure probability (CFP), which is used to address the failure probability of components in the SHA model. The simulation using the Monte-Carlo method is finally conducted on two satellites, which are deployed with the same multi-gyro subsystem but run on different orbits. The results show that the predicted useful life of the attitude control system (ACS) with consideration of abrupt failure, degradation, and running environment is quite different between the two satellites.