An Effective Ship Control Strategy for Collision-Free Maneuver Toward a Dock

Yonghui Shuai,Guoyuan Li,Jinshan Xu,Houxiang Zhang

doi:10.1109/access.2020.3001976

Abstract

Ship maneuvering toward a dock is a hot research topic in the field of autonomous ships. How to realize autonomous low-speed maneuver to a designated location under environmental disturbances is the fundamental problem at present. In addition, potential collisions with other nearby vessels and evasive maneuvers that meet maritime regulations increase the complexity of maneuvering. This paper presents an effective ship control strategy for collision-free maneuver toward a dock. In the strategy, a line-of-sight (LOS) algorithm is utilized to steer the ship along a pre-planned path toward the dock. A collision risk factor that takes ship's maneuvering characteristics, ship domain and relative velocity into account is designed for collision avoidance. Evasive maneuvers complying with the main rules of the international collision avoidance regulations at sea can be achieved based on the risk factor. A ship bumper is constructed, based on which the strategy can switch to either “path following” or “collision avoidance”. Numerical simulations for different encounter situations including head-on, starboard-crossing and overtaking under wind perturbations are carried out. The results show the proposed strategy is able to keep the ship domain free during maneuvering and steer the ship to the docking area in a safe and appropriate manner.

Highlights

With the rapid development of economic globalization, the quantum of international trade continues to increase
The strategy consists of a path following method and a collision avoidance mechanism
The path following method is developed to steer the ship along a planned docking path by using the LOS algorithm

Summary

Introduction

With the rapid development of economic globalization, the quantum of international trade continues to increase. Maritime transportation as the main mode of freight transportation accounts for about 70% of the total international trade. Autonomous ships are considered the future of the maritime industry for transportation, as it can realize costeffective shipping while ensuring ship safety. There are many practical problems that need to be solved at present. One of the most significant problems is how to steer the autonomous ship to a dock in a safe and efficient manner. Ship maneuvering in harbor areas under certain environmental conditions is a challenging manoeuvring assignment for captains, since the environmental perturbations, such as wind, wave and current, have a great impact on ship hull.

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