• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.265-266
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• 2023

With the development of science and technology, various research on ship collision avoidance has also developed rapidly. The research and development of ship collision avoidance technology has also received high attention from many researchers. This paper proposes a new collision avoidance algorithm for ships based on the artificial force field collision avoidance method. Using the simulation platform, the simulation results show that ships can successfully avoid collision in open water under single ship and multi ship situations, and the research results are relatively ideal.

• Journal of Navigation and Port Research
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• v.34 no.2
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• pp.105-110
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• 2010

The studies on automatic ship collision avoidance system, which have been carried out in the last 10 years, are facing on new situation due to newly developed high technology such as computer and other information system. It was almost impossible to make it used in real navigation field 3-4 years ago because of the absence of any tool to give other ship's information, however recently developed technology suggests new possibility. This study is carried out to develop the automatic ship collision avoidance support system which considers ship's manoeuvrability into it's collision avoidance algorithm. One of the important part in ship collision avoidance system is collision decision module which can calculate collision risk with other ships and act properly to avoid the situation. Many of previous researches are using present ship's dynamic data such as present speed, position and course to calculate collision risk. However when a ship commences avoidance action, the real situation is quite different with one that has been estimated by the ship's initial data due to the ship's manoeuvring characteristic. Therefore it is better to take into account ship's manoeuvring characteristic from the stage of collision decision in ship collision avoidance system. In this study, these effects are included in the developed system. The proposed system are verified its usefulness in numerical simulation environments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.129-134
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• 2004

Author presented some study with a title of "automatic control for ship collision avoidance system" in previous papers. The paper reported the tread of the study, un-sloved issues and outcome of the study. In this paper, some additional results will be reported. The first is the algorithm of avoidance of group ship that is one of the un-sloved issues. The algorithm is useful when a ship takes an avoiding action toward group fish boats and approaching group merchant vessel. The second is unified model for calculating ship collision risk. The collision risk changes with various meet type of ships. Therefor newly-developed model is suggested to take into account of these situations. Finally simulation is carried out to verify suggested algorithm and model in various ship encounter situations..

• Journal of the Society of Naval Architects of Korea
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• v.58 no.3
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• pp.191-197
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• 2021

This study addresses autonomous ship collision avoidance in narrow channels using curvilinear coordinates. Navigation in narrow channels or fairways is known to be much more difficult and challenging compared with navigation in the open sea. It is not straightforward to apply the existing collision avoidance framework designed for use in the open sea to collision avoidance in narrow channels due to the complexity of the problem. In this study, to generalize the autonomous navigation procedure for collision avoidance in narrow channels, we introduce a curvilinear coordinate system for collision-free path planning using a parametric curve, B-spline. To demonstrate the feasibility of the proposed algorithm, ship traffic simulations were performed and the results are presented.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.81-86
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• 2003

The studies on automatic ship collision avoidance system, which have been carried out last 10 years, are facing on new situation due to newly developed high technology such as computer and other information system. It was almost impossible to make it used in real navigation 3-4 years ago because of the absence of the tool to get other ship's information, however recently developed technology suggests new possibility. This study is carried out to develop the algorithm of automatic ship collision support system. The NOMOTO ship's mathematic model is adopted in simulation for its simplicity. The fuzzy reason rules are used for course-keeping system and for the calculation of Collision Risk using TCPA/DCPA. Moreover‘encounter type’ between two ships is analyzed based on Regulations for Preventing Collisions at Sea and collision avoidance action is suggested, Some situations are simulated to verity the developed algorithm and appropriate avoidance action is shown in the simulation.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.375-381
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• 2003

The studies on automatic ship collision avoidance system, which have been carried out last 10 years, are facing on new situation due to newly developed high technology such as computer and other information system. It was almost impossible to make it used in real navigation 3-4 years ago because of the absence of the tool to get other ship's information, however recently developed technology suggests new possibility. This study is carried out to develop the algorithm of automatic ship collision support system. The NOMOTO ship's mathematic model is adopted in simulation for its simplicity. The fuzzy reason rules are used for course-keeping system and for the calculation of Collision Risk using TCPA/DCPA. Moreover ‘encounter type’ between two ships is analyzed based on Regulations for Preventing Collisions at Sea and collision avoidance action is suggested. Some situations are simulated to verity the developed algorithm and appropriate avoidance action is shown in the simulation.

• Journal of Navigation and Port Research
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• v.28 no.6
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• pp.475-480
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• 2004

Author presented some study with regard to “automatic control for ship collision avoidance system” before. Those papers are to deal with unsolved problem,; in the previous study. In this paper, two issues relating to ship collision avoidance were investigated. One is to suggest a new algorithm of avoidance of a group ship. This algorithm is useful when a ship takes avoiding action for a group fish boats and a group of merchant vessels. In the stage of taking avoidance action, newly-developed algorithm was used. the other is to develop a unified model of collision risk. Generally collision risk changes according to various type of encounters. The new model is to take into account of these situations. The above-mentioned algorithm and model were verified through simulation under various encounters between ships.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.58-65
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• 2019

The stability, reliability and efficiency of a smart ship are important issues as the interest in an autonomous ship has recently been high. An automatic collision avoidance system is an essential function of an autonomous ship. This system detects the possibility of collision and automatically takes avoidance actions in consideration of economy and safety. In order to construct an automatic collision avoidance system using reinforcement learning, in this work, the sequential decision problem of ship collision is mathematically formulated through a Markov Decision Process (MDP). A reinforcement learning environment is constructed based on the ship maneuvering equations, and then the three key components (state, action, and reward) of MDP are defined. The state uses parameters of the relationship between own-ship and target-ship, the action is the vertical distance away from the target course, and the reward is defined as a function considering safety and economics. In order to solve the sequential decision problem, the Deep Deterministic Policy Gradient (DDPG) algorithm which can express continuous action space and search an optimal action policy is utilized. The collision avoidance system is then tested assuming the $90^{\circ}$intersection encounter situation and yields a satisfactory result.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.75-81
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• 2019

This study presents an automatic collision avoidance algorithm for autonomous navigation of unmanned surface vessels. The performance of the collision avoidance algorithm is heavily dependent on the estimation quality of the course and speed of traffic ships because collision avoidance maneuvers should be determined based on the predicted motions of the traffic ships and their trajectory uncertainties. In this study, the collision avoidance algorithm is implemented based on the Probabilistic Velocity Obstacle (PVO) approach considering the maritime collision regulations (COLREGs). In order to demonstrate the performance of the proposed algorithm, an extensive set of simulations was conducted and the results are discussed.

• Journal of Korea Ship Safrty Technology Authority
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• s.38
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• pp.69-77
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• 2015

If we don't know the intention of altering course of a target ship when being in a head-on or a crossing situation, we may be confused about our decision making to change our course for collision avoidance and be in a danger of collision. In order to solve these problems, we need to develop an automatic detection system on altering course of a target ship for efficient collision avoidance. In this paper, we proposed an early detection system on altering course of a target ship using the steering wheel signal. This system will contribute to the reduction of collision accidents and also be used to the VTS system and the analysis of marine accidents.