Time-Synchronized Control of Unmanned Dynamic Positioning Ships

In this work, a time-synchronized control (TSC) for the unmanned dynamic positioning ship is studied. Different from the traditional control, a new concept of time-synchronized stability (TSS) is defined based on ratio persistence, which can guarantee different freedom degrees of ship tracking errors converge to zero at the same moment. In addition, the classic sign function is revisited and a norm-normalized sign function is defined. Combined with the sliding mode control (SMC) and TSS, a TSS is designed for the unmanned dynamic positioning system (UDPS) of ships. Finally, simulation is constructed to demonstrate that tracking errors in the different freedom degrees of dynamic positioning ships converge to the equilibrium point at the same moment.