Robust Nonlinear Backstepping Anti-Disturbance Fault-Tolerant Control of Ships

In this article, a robust nonlinear backstepping anti-disturbance fault-tolerant control scheme is developed for surface ship with time-varying environmental disturbances and actuator faults conditions. The ship tracking composite anti-disturbance fault-disturbance control law is designed by the fusion of disturbance observer and fault observer with backstepping control method. The disturbance observer is utilized to provide on-line estimates of the disturbance in the time-varying ocean environment. The fault observer is employed to provide the on-line estimates of the occurrence of actuator faults. It is proved by illustrative simulations that the closed-loop control system is stable and the ship position and heading tracking can be achieved.