Research On Fault Diagnosis Approach For Attitude Control System Of Satellite

As the structure and performance of the spacecraft become more sophisticated, it is crucial to develop the fault diagnosis strategy to ensure the stability, reliability and safety of spacecraft. In this dissertation, the fault diagnostic techniques for the attitude control system of satellite (ACSS) are studied from the theoretical aspect, using the Empirical Mode Decomposition (EMD) method and adaptive fault diagnosis observer. The main contributions are included as follows:First, fault diagnosis problem and the development of fault diagnostic technology for the spacecraft are introduced. Then, the fault diagnosis methods for the spacecraft are surveyed systematically, and the potential trends of fault diagnostic techniques for the spacecraft are given.Secondly, this paper introduces the basis of the attitude descriptive methods, attitude kinematics and dynamics equations. The instruments and actuators of the ACSS are described. Then the simulation model of the ACSS is constructed and the potential faults are analyzed to give a platform for the study of fault diagnosis strategies.Then, the EMD based fault diagnosis approach for the inertial sensor fault is proposed. First, the output signals of gyroscopes are analyzed using EMD method to extract the characteristic functions adaptively, and the characteristic functions are measured by the energy entropy to detect and isolate the gyroscope fault. Simulation results demonstrate the proposed method has a good performance. Then, in order to reduce the computational burden, an integrated fault diagnosis method is proposed, which combines the EMD method and parity space approach. Finally, an actuator fault diagnosis scheme based on adaptive fault diagnosis observer is investigated for the ACSS. By using an adaptive radial basis function (RBF) network to approximate the model of fault, the proposed observer can estimate the abrupt and incipient fault effectively. The weight updating algorithm of the RBF network is established in the sense of Lyapunov theory. The proposed fault diagnosis observer is compared with a fault detection observer to demonstrate its performance.