Nonlinear Adaptive Observer-Based Fault Diagnosis for Satellite Actuator

This paper studies the multi-structural fault mode of satellite actuators, and use numbers of unknown parameters as fault indicators. The problem of adaptive state observer design for nonlinear systems with unknown parameters is dealt with by applying Lypunov method. The nonlinear object is firstly linearized into Lipschitz system, and then by analyzing the sufficient condition for asymptotic convergence of the observer, the structure of observer and the adaptive laws for parameter estimation are given. Finally, the adaptive observer is employed to estimate the faults of satellite actuator. Numerical simulation results show that this method is effective and able to quickly detect faults.