Research On Path Planning Of Unmanned Surface Vehicle Based On Navigation Errors

Unmanned Surface Vehicle(USV)has been widely used in civil and military fields such as salvage and marine resource detection,because of its intelligence,small size and low cost.Path planning,as one of the key functions of USV,is a prerequisite for USV to safely complete cruise missions.In this thesis,considering the influence of navigation errors,the key technology of path planning method based on navigation error constraint is studied.The main work is as follows:(1)The common coding method of grid method and the grid-based environment model based on hierarchical strategy are studied.The basic principle of the four methods of fast expansion random tree,bidirectional search tree,probabilistic route graph method and A*algorithm are introduced.The simulation results show that the global path planning method based on A*algorithm is better than the other three programming methods.(2)The local static path planning problems resulting from navigation errors are studied.The basic principle of genetic algorithm is expounded;the navigation error space model is established;the formulas of transfer cost and collision probability are deduced.In addition,the concrete process of path coding,initialization population and operation operator is given.In the simulation experiment,the local static path planning based on navigation error constraints has safety and reliability.(3)The problem of USV dynamic obstacle avoidance path planning is studied.Several collision risk models are analyzed and compared.Then,based on the basic principles of COLREGS and velocity obstacle avoidance method,the collision avoidance model of USV is deduced,and the security and feasibility of the local dynamic path planning method based on the velocity obstacle avoidance are verified by simulation experiments.(4)The path planning system based on navigation error constraint is designed.The structure and basic principle of the whole path planning system are described in detail.In the simulation experiment,the security,feasibility and reliability of the path planning method are verified.