Research On Near Space Vehicle Actuator Fault Diagnosis And Simulation Platform

This dissertation focus on the actuator fault diagnosis (FD) problems of near space vehicle (NSV) during re-entry phase. Takagi-Sugeno (T-S) fuzzy model is employed to approximate the NSV attitude dynamics. Based on the fault diagnosis observer and linear matrix inequalities (LMIs) approach, an adaptive observer and fault estimation algorithm is proposed and is verified in the MATLAB simulation platform. And a real time fault diagnosis simulation platform technology for NSV flight control system is also introduced in this paper.Firstly, the history and the development of FD is surveyed, especially the method based on observer is mentioned. Then an overview of the state of study and research about NSV is given, the FD problem of NSV is proposed.Secondly, the nonlinear mathematic model of NSV is introduced. Takagi-Sugeno (T-S) fuzzy model is employed to approximate NSV attitude dynamics during re-entry phase. The state feedback control law is proposed for NSV T-S fuzzy model. All the above is the foundation of the following study of FD of NSV.Thirdly, a fault detection method is presented. Then an adaptive observer and fault estimation algorithm is proposed for NSV with external disturbances and actuator fault. To minimize the effect of external disturbances, the performance index is introduced. The parameters of observer are obtained through solving the LMIs. Besides, the method proposed in this dissertation is compared with the classic adaptive fault estimation .The simulation result demonstrates that the algorithm proposed can estimate both constant and time-varying fault fast and accurately with satisfactory disturbances attenuation.Finally, technology on real-time fault diagnosis simulation platform for flight control system of NSV is studied, both hardware construction and software modules programming is introduced. The experimental result shows that the real-time fault diagnosis simulation platform can cope with actuator fault detection in real-time mode, which also confirms the rightness and effectiveness of the theoretical conclusion developed in this dissertation.