Observer-Based Fault Detection For Satellite Attitude Control Systems

A satellite will be impacted by various spatial disturbance torque. In this case, whether the satellite can be normally operated and whether the satellite failure can be detected are issues to consider during satellite failure detection. Based on three-axis stabilized satellite attitude control system, a fault detection approach is presented and a relevant simulation is given to show the design procedures and illustrate the effect of the proposed approach. The main contribution is as follows:1. The type of appropriate gestures is selected to describe the satellite's attitude. A mathematical model of the satellite attitude system is established.2. The parametric design method for Luenberger observers with unknown inputs is used to detect fault of the satellite attitude control system. When this system occurs actuator failure or sensor failure, the method can quickly detect the fault and the method can be done on a particular form of disturbance completely decoupled.3. A fault detection approach based on proportional integral (PI) observer is proposed. With a PI observer including proportional gain matrix L, integral gain matrix F, output error weight matrix K and integral weight matrix H, the proposed approach can provide more design degrees of freedom. In this method, the robustness for the disturbance is characterized by the index H∞, and the insensitivity of the fault signal is characterized by the index H ?. With these preliminaries, this method further transforms the issue of system stability, robustness and fault detection sensitivity into a group of matrix linear matrix inequalities. Simulation results show that the proposed approach can accurately detect a variety of actuator faults and sensor faults; also the error dynamic system obtained from this method has a good disturbance attenuation property.