Mode-dependent supervisory switching fault-tolerant control for dynamic positioning ships with actuator faults

A mode-dependent supervisory switching fault-tolerant controller is proposed for dynamic positioning (DP) ships. First, the input-to-state stability (ISS) of nonlinear switched systems with a larger class of mode-dependent switching signals is studied, which requires fewer constraints on the subsystems. By appropriately constraining the switching signals, a class of mode-dependent exponentially weighted integral ISS for the switched system is achieved. Furthermore, a mode-dependent scale-independent hysteresis (MDSIH) switching logic is designed, which takes into account both model estimation errors and time scales. This logic avoids the stagnation issues inherent in traditional scale-independent hysteresis switching, which are often caused by improper hysteresis constant selection. It enables more proactive switching, which is crucial for effective fault-tolerant control (FTC). Lastly, the design principles of the multi-estimator and multi-controller are given for DP ships. By employing the designed MDSIH switching logic, the DP system can tolerate sudden actuator faults while ensuring the boundedness of all signals in the closed-loop switched system. •This paper proposes a less conservative assumption condition for the ISS of switched systems.•This paper introduces a novel mode-dependent exponentially weighted integral ISS.•A new MDSIH switching logic is proposed, which, unlike traditional scale-independent hysteresis switching logic that only considers estimation error, takes into account both estimator performance and time scales.•A novel mode-dependent supervisory switching fault-tolerant controller is designed for DP ships.