Active FTC for waterjets propelled ships based on Adaptive Estimator and Sliding Techniques

Abstract

Abstract: This paper focuses on the design and validation of an active Fault Tolerant Control (FTC) approach dealing with sensor and actuator faults for a ship propelled by two water jets. The proposed FTC relies on an adaptive estimation to reconstruct sensor faults and a second order sliding mode observer based on an adaptive super twisting algorithm to reconstruct the actuator faults. A nonlinear model of the considered ship, issued by a previous work, is used to prove the effectiveness of the proposed FTC in the path following maneuvers, speed regulation, and tracking course. The inputs of this model are the command orders to apply to the water jets including the two engines, the steering and reversing units for each jet. Details of the design process of the faults reconstruction and reconfiguration are given. The stability of the closed-loop system and uniform boundedness of the tracking error are proved based on Lyapunov theory. Simulations with many faults scenario are carried out. Results show that the proposed controller can successfully accommodate faults associated with sensors and actuators.