Research On Early Warning Of Ship Collision Danger Based On Composition Fuzzy Inference

In recent years,with the development of human science and technology,maritime traffic has become more and more prosperous,which has brought a lot of convenience to human life,but at the same time,more and more problems have gradually emerged.Frequent ship collision accidents have caused serious economic losses and even threatened the safety of human life,and the aggravation of pollution caused by ship collision on the ecological environment can not be ignored.In spite of all kinds of research and methods in recent years,ship collision accidents are still inevitable and occur constantly.The issue of ship collision avoidance at sea has gradually become a research hotspot of marine issues.Most of the collision accidents at sea are caused by human’s misjudgment and misoperation.Reducing human’s misoperation is an important topic in the research of ship collision avoidance.In the daily navigation of ships,human factors are mainly reflected in the subjective decision-making of the sailor in the process of driving.The key for the sailor to make a reasonable and correct collision avoidance behavior is to grasp the accurate collision avoidance time and choose a reasonable collision avoidance decision.Therefore,in ship navigation,it is the key to accurately judge the collision risk and provide early warning for the sailor to make the correct collision avoidance decision.In this paper,a composition fuzzy inference method is proposed,which combines more than one fuzzy inference process and introduces as many factors related to ship collision risk as possible,to provide early warning for ship collision risk,and reasonable reference for sailors’ decision-making in combination with the COLREGs.The main work of this paper is as follows:(1)Fault tree analysis method is used to identify and evaluate the risk of ship collision accident,so as to judge the collision risk of ship in the process of navigation.Through statistical analysis based on the collected data of ship collision accidents,the fault tree of ship collision accident system is established,and the qualitative and quantitative analysis of the fault tree of ship collision accident system is carried out,so as to realize the screening of important causes of ship collision accidents and reduce the complexity of research.(2)By using the method of composition fuzzy inference,the ship collision risk index model is established to comprehensively analyze the collision risk degree of ships.when determining the collision risk factors,the influence of the ship’s own factors and environmental factors on the collision risk index of ship is comprehensively considered.(3)The ship domain is regarded as the safety domain to avoid collision between ships.By establishing the model,as many factors related to ship collision risk as possible are introduced into the calculation of ship domain.Similarly,the size of ship domain is obtained by using composition fuzzy inference,so as to carry out collision risk early warning according to the range of ship domain,and carry out collision risk early warning under different situations whether the ship implements collision avoidance measures provides a reference.(4)The experimental environment is built in MATLAB software,and the fuzzy reasoning system based on if-then fuzzy rules is established.The simulation results are analyzed and discussed.Through the simulation calculation and comparison of the advantages and disadvantages of the two methods,the collision risk of the ship in the process of navigation is obtained,and the collision risk warning and collision avoidance decision are provided for the sailor,so as to reduce the occurrence of collision accidents.The experimental results show that the method using composition fuzzy inference to early warn the danger of ship collision has smaller error and easier operation than the traditional methods.