A Study on an Efficient Positioning Control Method for Thruster Assisted Position Mooring Systems

The present study focuses on a finite-time adaptive positioning control for marine vessels that are equipped with a thruster assisted position mooring system (TAPMS). This control strategy takes into account various factors, including thruster dynamics, input saturation and unknown time-varying disturbances. A finite-time disturbance observer (FTDO) is constructed to estimate the disturbances. To address the thruster input saturation issue, a finite-time auxiliary dynamic system (FTADS) is employed. Based on the disturbances estimation and the FTADS, a finite-time command filtered backstepping (FTCFB) control law is implemented to achieve the station keeping of the vessel. Furthermore, the Lyapunov stability theory is applied to prove that every signal within the control system is finite-time bounded. Finally, the simulation results verify the superior positioning performance of the proposed control method, confirming its ability to achieve fast and accurate positioning with minimal error margins.