Fault-Tolerant Optimal Dynamic Positioning Control for Ships: An Adaptive Dynamic Programming Method

This paper addresses the fault-tolerant optimal tracking control design problem for marine dynamic positioning under actuator faults, disturbances, and model uncertainties. A novel control strategy integrating the adaptive dynamic programming (ADP) and the nonlinear observer is proposed to achieve precise trajectory tracking, energy optimization, and fault tolerance simultaneously. Firstly, an observer-based backstepping controller is designed to estimate composite term including external disturbances, uncertainties, and actuator faults. Then, the ADP technique with a single critic network is employed to solve the nonlinear optimization problem for the error system, realizing optimal control performance while minimizing the cost function. The stability of the closed-loop system is rigorously proven via Lyapunov theory, ensuring that all signals are uniformly ultimately bounded. Simulation results demonstrate the superiority of the designed strategy.