Autonomous docking of a feeder vessel

Abstract

Autonomous sailing is seen as one of the possible solutions to cope with the decrease in qualified personnel and to minimise the risk to humans and ships in challenging conditions. Autonomy is not limited to sailing a vessel safely through the seas, but it also includes docking the vessel. A feeder vessel distributes cargo and spends a relative large percentage of its time on (un)docking. Automating this part of the operation is expected to help save on resources. The objective of this work is to automatically approach a dock with an underactuated vessel. It comprises of both the design of a time-dependent trajectory, and a controller that can track this trajectory. The solution is tailored for our 71 m long feeder vessel designed for the eu-h2020 Moses project. The focus is on approaching the dock from cruising speed until the speed of the vessel is near-zero. The result of the study is a high-fidelity time simulation that shows the behaviour of the vessel in combination with the control system when it approaches a dock. The simulations show that the ship can approach the dock with coupled azimuthing thrusters to a speed when the bow thrusters become effective. The vessel then becomes fully actuated and can safely dock with its dynamical positioning system.