Ship manoeuvrability varies with speed and is affected by environmental disturbances, making unberthing control challenging. To address this, a control method using an online estimation model is proposed, in which the parameters of a linear motion model are sequentially updated based on the observed ship velocities and actuator inputs. A linear quadratic regulator was applied for route tracking, and a bias term was introduced to estimate and compensate for steady external forces, such as wind and tidal currents. The proposed method was validated through actual sea experiments using a full-scale vessel. The control system achieved accurate tracking using an unberthing manoeuvre. It also demonstrated effective disturbance compensation and adaptability to changes in actuator effectiveness. These results confirmed the practicality of the proposed approach for real-time unberthing operations under actual sea conditions.
Kashiwagi et al. (Thu,) studied this question.