Research On Path Planning Of Underwater Glider

Low-energy,long-range underwater vehicle has been a hot research issue in many countries.Driven by this demand,a new concept of underwater vehicle-underwater glider emerged.Underwater glider is driven by net buoyancy.It has the advantages of strong endurance,low cost and low noise.It is suitable for long-period and long-range underwater missions.Path planning is one of the difficult problems in the field of underwater glider and there are many unsolved problems.Based on the particularity of underwater glider's trajectory,this paper simplifies the problem of underwater glider's three-dimensional path planning into the problem of obstacle avoidance on two-dimensional longitudinal section and the problem of global path planning on two-dimensional horizontal plane.The purpose of this paper is to solve the problems of obstacle avoidance and global path planning in some simple cases according to the characteristics of underwater glider with improved optimization algorithms,hoping to provide some reference for the research of path planning of underwater glider.Specifically,it includes the following aspects:(1)Optimization of underwater glider path parameters based on optimal energy consumption.Firstly,the steady motion process and forces of underwater glider are analyzed,and the energy consumption model is established systematically.Then,based on two common cases including single period and fixed horizontal gliding distance,the variation trend of energy consumption with gliding parameters is studied.(2)The problem of avoiding underwater obstacles in a single movement cycle.Firstly,the traditional artificial potential field method isimproved to overcome the common problems including local extremum problem and unreachable target problem,and the velocity potential field function is introduced to transform the static potential field into the dynamic potential field.Then,considering the motion constraints and introducing the ocean current force,the simulation experiments are carried out in static and dynamic environments.The simulation results show that the method proposed can make underwater glider avoid the static and dynamic obstacles under the action of current or without current.(3)The global path planning problem under multiple motion cycles.Firstly,the required environment information is extracted from the electronic chart and the model is established by the grid method.Then,the ocean flow field is generated by the stream function method,and the ocean current information is stored in the grid data structure.Finally,the path evaluation functions are constructed with the optimization objectives of energy consumption,path length and path safety,and GA-PSO hybrid algorithm is used for global path planning of underwater glider.The simulation results show that the optimal global path can be generated according to the optimal objectives under the action of ocean current,and the convergence speed of hybrid algorithm is faster than that of single algorithm.