Study On Decision-making Methods Of Ship Collision Avoidance

In case of ship collision, the ship is seriously damaged, the goods are jeopardized, but the people are killed or horribly mutilated, and even the sea is extremely polluted. It is clear that most of collision accidents are due largely to the navigator's negligence, fault and actions failed to abide by the international regulations for preventing collision at sea. Reducing human error, therefore, is crucial for navigation safety. Consequently, the research on decision-making of ship collision avoidance is a key in 21 century. The paper, based on the summary and analysis on research done before, using qualitative and quantitative analysis methods and at the view of subjective requisition united with objective requisition, has done the following work:The knowledge in the domain of ship collision avoidance is analyzed and the collision mechanism, process and tactic are further studied. Based on collision regulation and qualitative and quantitative analysis, three encounter situations are sorted and collision avoidance action situations are further divided.In view of the divisions of collision avoidance situation, the movement parameters of both own-ship and target ship are calculated considering the factors of own-ship's speed, the speed ratio of both encounter ships and the encounter situation to lay a solid basis for decision-making of ship collision avoidance.According to the connotation of DCPA and TCPA concepts, the concept of collision risk is put forward. By using the fuzzy mathematics theory, the model of judging collision risk is built, which take into account of the factors such as ship's maneuverability, visibility and so on.Based on the international regulations for preventing collision at sea and ordinary seamanship, the multi-ship encounter situations have been categorized. The way of 'avoiding key ship' has been proposed inmulti-ship encounter situations. And the qualitative analysis has been carried out if non-coordinated operation has appeared when taking this method.The research on decision-making of ship collision avoidance is a hot topic in navigation circle. The paper has done some job in decision-making of collision avoidance and it is in line with the actual situation at sea to some extent. However, great efforts are still being made to study further the multi-ship encounter situation and the model for decision-making of collision avoidance.