Design Of The Fault-Tolerant Flight Controller Based On Switching Mechanism

The flight controller plays a very important role in guaranteeing flight safety and improving the performances of airplanes. The flight controller must have good performances in fault tolerance because flight control requiring high standards of safety and reliability. As one of the most important faults in control system, the actuator fault affects the system performance seriously. Nevertheless, traditional fault-tolerant flight controller only considers one type of actuator fault or two. Hence, a fault-tolerant flight controller based on switching mechanism is designed in this dissertation. A wing rock model as its controlled object is selected in this dissertation, which affects the airplane performance of safety. The controller considers the uncertainty of the wing rock model, and several types of common actuator faults at the same time, such as bias, loss-of-effectiveness, stuck, and the nonlinearity.After introducing the theory and the design ideas of the flight controller simply, a unified fault model for the several types of common actuator faults is established in this dissertation, and then the mathematical mode of the controlled object-wing rock model is established. Considering the characteristics of the wing rock model and the actuator fault model, firstly an adaptive logic-based switching controller is designed in this dissertation. However, this controller cannot solve the actuator stuck fault. Therefore, using redundancy design theory, the backup actuators for the wing rock control system are designed in this dissertation, meanwhile new switching mechanism is designed. Then the design of fault-tolerant controller based on switching mechanism is finished. At the end, the simulink model of the wing rock fault-tolerant control system is established in this dissertation, and the designed control system is simulated and analysed in the performance.The results of simulation and analysis show that the fault-tolerant flight controller based on switching mechanism, applied to wing rock model, can eliminate the rock of wing, no matter when or what kind of actuator fault occurs. This controller which has good performances in fault tolerance can satisfy the requirement in flight control of the safety performance.