Research On Global Path Planning Method Of Unmanned Surface Vehicle Based On Electronic Chart

In recent years,the strategic development direction of all countries in the world is gradually spread out on the ocean.Unmanned surface vehicle is the hot spot of development.As an application field of ship intelligence,unmanned surface vehicle has a broad prospect in both military and civil use.The autonomous navigation ability of unmanned vehicle is an important indicator of its intelligence.The global path planning is the first step for the autonomous navigation of the unmanned surface vehicle.At this time,planning a safe and reasonable path according to navigation requirements will effectively improve the operating efficiency of the unmanned craft and reduce the workload of subsequent ship collision avoidance.In this thesis,we study the global path planning of unmanned surface vehicle is taken as the research object,and the S-57 electronic chart data analysis and storage,environmental modeling methods and path planning methods,so as to realize the route planning that meets the navigation requirements of unmanned surface vehicle.(1)Environmental modeling method based on electronic chart.Electronic chart can provide detailed and accurate global information.This thesis analyzes the S-57 electronic chart to extract the geographical information of the sea area.Then a regular hexagonal grid is used to build the environment model,and the cube coordinate system is used to transform the regular hexagonal grid coordinates,which simplifies the coordinate calculation and improves the efficiency of the path planning algorithm.Finally,the performance of square mesh and hexagonal mesh is compared and analyzed.(2)Global Path Planning Method for Unmanned Vehicles.Based on the environment model established above,A*algorithm is used in this thesis to study the global path planning of unmanned vehicle.A*algorithm is improved from two aspects of heuristic function and search strategy to improve the search efficiency of A*algorithm.According to China Coastal Inland River Navigation Rules,the influencing factors of the navigation safety of unmanned craft are analyzed,and the constraint conditions and corresponding treatment schemes are given from two aspects of ship maneuverability and navigation safety.(3)Experimental results show that the hexagonal grid environment model has better performance than the square grid environment model.Then verify the feasibility and the corresponding treatment scheme given in this paper,the extension of the neighborhood and search optimization combination get more groups of experimental conditions,analyzed the influence of the combination method of path planning parameters,Finally,select the optimal scheme of this experiment and analyze the effectiveness of the global path planning method in this thesis by using multi-objective experimental data.The experimental results show that the modeling method of regular hexagonal grid environment and the coordinate transformation method of cube coordinate system can improve the efficiency of path planning algorithm,Using the real data in the electronic chart as the data source of the environmental model is more practical for planning the route,Considering the factors of ship maneuverability and navigation safety in the water environment,add some constraints to the path planning algorithm can preliminarily obtain the sailing route under the premise of satisfying the navigation constraints of the unmanned vehicle.