Velocity control of dynamic positioning vessel based on linear active disturbance rejection controller with environmental disturbance

The position keeping of a vessel typically can be accomplished through the implementation of a dynamic positioning (DP) system without specifically controlling the vessel velocity. However, in some offshore operations, the displacement and velocity-controlled may be required simultaneously. To address this issue, present study propose a velocity direct control strategy for a dynamic positioning (DP) vessel by applying Linear Active Disturbance Rejection Control (LADRC) facilitating the vessel to follow a designated trajectory at a specified velocity. Comparative analysis between conventional path tracking control strategy and proposed strategy was carried out utilizing time-domain simulations. The comparisons demonstrate that conventional tracking strategy cannot achieve high-accuracy path tracking and overshoot-free velocity control at the same time, while the proposed velocity direct control strategy can fulfill overshoot-free velocity control across the velocity step input with small offset. The numerical simulations of Z-shaped routes under environmental disturbances further confirm the effectiveness of the proposed method, particularly when it comes to trajectories with abrupt changes. • A direct velocity control strategy for DP vessels is proposed. • A hybrid LADRC incorporating both vessel velocity and trajectory offset is designed. • A positioning target point selection strategy based on the current vessel position is proposed.