Research On Satellite Attitude Control System Based On Robust Fault-Tolerant Control

Nowadays, satellite control system's autonomous fault diagnosis and fault-tolerant control is one of the hottest research areas around the world.This paper did research on fault-tolerant control of satellite control system. Based on general discussion over all available fault-tolerant control methods, we chose linear matrix inequation (LMI) to do research on robust fault-tolerant control. The result could apply to the control problem of three-axis stabilized directional satellite control system. Also, we use our result on fault diagnosis of different types of faults on sensor and execution system to prove the efficiency of our method. The research mainly consists:The design method of robust fault-tolerant control systems based on LMI for linear multivariable system is studied. Sufficient conditions for the existence of controller are analyzed. And effective controller design methods are provided via LMI approach. If the satisfying controller exists, and then a region of the controller is given. In addition, other performances can be considered and designed. The problem of robust and reliable H_∞fault design for linear uncertain systems with time-varying norm-bounded parameter uncertainty and also with actuator failures based on Linear Matrix lnequality(LMI). An H_∞-norm bound constraint on attenuation of augmented disturbances are introduced. Sufficient conditions for the existence of controller are derived. Ranges of consistent indices are analyzed. And effective controller design methods are provided via LMI approach.Apply above method on the controller design of satellite position control system. We designed controller separately for the fault condition of execution system and sensitive device, and did mathematical simulation over the algorithm. We compared our method with the traditional PID control method. The results shows that when the execution system and sensitive device under fault condition, robust fault-tolerant control makes pointing precision and stability precision of satellite position control meet the requirements before fault condition occurs.