Fault Isolation And Adaptive Reconfiguration For Flight Control System

It is assurance of flight safety to achieve the high reliability of flight control system. When any fault occurs, how to change control laws to make the fault aircraft maintain the safe capability is very important for aircraft mission success and safe return to base. So future flight control system is to be designed with the available technology of autonomous decision and control, and fault tolerance control in order to increase the aircraft survivability. Therefore, research on techniques of fault isolation and adaptive reconfiguration for flight control system has become a critical issue to ensure safety, reliability and fault tolerance performance of aircraft.This dissertation studies the problem of fault isolation and adaptive reconfiguration for sensors and actuators in flight control system according to the characteristic and safety capability of modern flight control system. Bases on model-following adaptive control theory, the architecture of fault tolerant flight control system is set up perfectly by combining a new adaptive concept which is self-study, self-setup, self-decision and intelligence control, modern control and fault tolerance control. Centered on adaptive concepts, the dissertation chooses corresponding adaptive mechanism to achieve fault isolation and adaptive reconfiguration for flight control system.The main contributions of this dissertation are as followings:Considered the real-time and closed loop feedback in flight control system, a robust adaptive observer based sensor fault isolation and adaptive reconfiguration method is proposed by using multiple model adaptive conception. A set of observers are set up in order to restrain model uncertainties, noises and interaction of sensor outputs. The information of the observers is applied for sensor fault isolation and reconfiguration to ensure stability of the closed loop feedback system. Due to using sequential analysis for the remains detection, the probability of false and missing alarm is avoided. Simulations results show the validity of this method.