Design of UDE-based dynamic surface control for dynamic positioning of vessels with complex disturbances and input constraints

In practice, dynamic positioning (DP) vessels are subjected to complex disturbances as well as the magnitude and changing rate constraints of the thrusts and moments. This study applied a dynamic surface controller based on an uncertainty and disturbance estimator (UDE) to a DP vessel with complex disturbances and input constraints. The UDE was designed to estimate and handle the complex disturbances. An auxiliary dynamic system (ADS) and smooth switching function were employed to compensate for the input constraints and avoid the singularity phenomenon caused by the ADS, respectively. The combination of the UDE method and dynamic surface control (DSC) technology significantly simplified the design process for the control law and increased the practicability for DP vessels. The stability of the proposed control law was proved using the Lyapunov theory. The effectiveness of the control law and possibility of actually applying it to a DP vessel were verified using simulation experiments.

Automated summary

This study introduced a dynamic surface controller based on an uncertainty and disturbance estimator (UDE) for DP vessels, which also utilized an auxiliary dynamic system (ADS) and smooth switching function to handle complex disturbances and input constraints. The combination of these methods simplified the control law design process and increased practicality for DP vessels, with stability proven using Lyapunov theory and effectiveness verified through simulation experiments.