Fault detection algorithm for wheel based on adaptive observer

An nonlinear adaptive observer algorithm was presented for satellite reaction wheels fault detection. Firstly, nonlinear adaptive observer for general nonlinear system was designed, and its time-variant gain array could be solved directly from analytical expressions. Then fault detection algorithm and fault detection strategy were given. After describing single wheel model and dynamics model of three-axis wheels system, practical full order nonlinear adaptive observer was discussed. Finally, simulations were finished on the assumption that wheel was invalid suddenly or its friction moment increased. The simulation results showed that the proposed fault detection algorithm could track system state quickly in the case of none system faults, and it was able to detect fault in time when fault occurred.