Flight Control System Fault Detection And Isolation Of Theoretical Research And Real-time Software Development

Self-Repairing Flight Control System (SRFCS) is a kind of active-and passive failure tolerant control based on the Fly-by-wire flight control system, and it is also an important tendency of the future flight control system. Using aircraft's onboard computer thoroughly, the SRFCS could enhance the flight control system's reliability, survivability, maintainability and lower Life Circle Cost (LCC) while do not use more hardware. Failure Detection and Isolation (FDI) is the key technique of SRFCS. which can forecast the occurrence of potential failure, tell why and where it occurs, and then provide relevant information for trigger test, control law reconfiguration and automated maintenance diagnostic.In this thesis, the FDI technique is studied and developed firstly. According to the requirement of the project, the real-time FDI software of SRFCS is designed based in the FDI technique.Since the western countries began the SRFCS research in the eighties, theory of signal detection is used in FDI, and it was successful in some FDI functions in several types of testing aircraft. China did the SRFCS research recently, but lack of the engineering FDI algorithm. Because the "model based signal detection algorithm" is sensitive to the matching accuracy of the mathematics model and aircraft has prominent nonlinear aerodynamic factors, it is difficulty to upgrade the ability of FDI based on the classical signal detection theory and data fusion only. But time-frequency domain analysis and artificial intelligence provide the new way to FDI. So in this thesis, after finished the real-time FDI software of SRFCS, we will study the new FDI algorithm.The main contributions of this thesis are shown as follows:Firstly, an algorithm of parity residuals and the theory of residual vector data fusion are studied and developed. The detection methods of single failure and multiple failures are ameliorated. Multiple failures include actuators' failures, actuator and single control surface's failures. The former can be detected by local detection, while the latter should be detected by local and global detection together.Secondly, the real-time FDI software of SRFCS is presented according to the specification of software engineering. Test results base on the data simulated by the means of Runge-Kutta prove the validity of the theory and the real time property of the software.Finally, the new detect theories are studied, the new ways to FDI are integrated and compared to prove the rationality and practicability.