Shared control of ship autopilots and human pilots for maritime autonomous surface ship in the presence of actuator anomalies

This paper investigates the heading control problem of maritime autonomous surface ships (MASSs) in the presence of actuator anomalies. A shared control framework that includes a ship autopilot and a human pilot, is constructed to realize the accurate tracking of the time-varying command signals. Specifically, the human pilot is responsible for high-level decision making such as anomaly estimation, anomaly correction and monitoring analysis, and the ship autopilot is responsible for a low-level task of command following. With the proposed shared control framework, the ability of the ship autopilot can be significantly enhanced compared to entirely automated tracking. Through Lyapunov stability analysis, it is proven that the tracking error is ultimately bounded, while all the signals of the closed-loop system remain bounded. Finally, a simulation example is presented to prove the effectiveness of the proposed shared control architecture for MASSs under actuator anomalies.