Observer-based Fault Detection and Estimation of Unmanned Underwater Gliders

In order to diagnose the faults for a class of underwater glider systems with Lipschitz nonlinear part, the kinematic and dynamic models of the underwater gliders considering the abrupt faults of the actuators are developed. Then the fault detection observer is designed considering the external bounded interference. The constant upper bound of the stable state estimation error in the faulty conditions is taken as the fault detection threshold to identify the fault occurrence. A fault estimator is thus designed to identify the magnitude and the time characteristics of the total impact of the fault. In this paper, the designed fault diagnosis strategy is proved theoretically, and the simulation results are given to verify the effectiveness of the proposed strategy.