Research On Fault Diagnosis Of Satellite Attitude Control System

Fault diagnostic technology is essential to ensure the operation of spacecraft's reliability and safety. As the studied object-satellite attitude control system, this paper studies the satellite attitude control system fault diagnostic techniques from the theoretical aspect, introducing Agent technology to establish the control system fault diagnosis architecture and using Wavelet analysis as a diagnostic tool for fault. Working papers include the following aspects:First, the paper gives the satellite attitude control system description and identifies the parts to study. On the basis of presentation od attitude descriptive methods, attitude kinematics, dynamics, measuring agency and executing agency, and analysis the characteristics of the satellite attitude control system, according to the differernt parts where the fault occur, and this paper has studied the fault which takes place in flywheel, gyro, or star sensor.Secondly, the paper cites Agent technology to design the satellite attitude control system fault diagnosis architecture. By analyzing and comparing different types of Agent and different organizational structures of Multi-Agent, this paper adopts the distributed Multi-Agent system to design the architectures of the satellite attitude control system which is made up of traditional satellite attitude control system, fault monitoring Agent, fault diagnosis Agent and fault-tolerant Agent. At the same time this paper designs fault diagnosis Agent based on discretion Agent structure, and fault diagnosis Agent is made up of the sensor, diagnostic module, fault positioning module and communication module.Thirdly, the paper uses wavelet analysis as the fault diagnosis method and does the research. It uses Mallat arithmetic as the fault diagnosis tool according to the multi-resolution and constructs estimate models to obtain residual signal, and then uses wavelet transform to disassemble and analyze the residual signal to diagnose fault. The simulation illuminates that this method can not only diagnose the time when the fault occurs, but also diagnose the location where the fault occurs. The result certifies the effectiveness of this method.