Path Planning And Tracking Control Of Ship Formation Based On Improved Artificial Potential Field Method

Our coastline is meandering,the ocean field is vast,Marine traffic development potential is great,and Marine resources are very rich.As the main object of exploitation and utilization of Marine resources,ships have special significance to the development of Marine transportation industry and ocean exploration.With the wide application of unmanned and intelligent vehicles and aircraft,the field of unmanned vehicles and drones is booming.he development of under-actuated unmanned surface vehicle(USV)is relatively slow compared with other unmanned devices.Single unmanned ship control and unmanned ship formation control are the two main research directions in the field of under-actuated unmanned surface vehicle(USV).Compared with the tracking control of single unmanned ships,the tracking control of unmanned ship formation has great advantages in the aspects of fuel and material supply,Marine resource exploration,maritime search and rescue,etc.Therefore,the research of unmanned ship formation tracking control based on single unmanned ship tracking control has gradually become the focus of academic research.Based on the path planning and tracking control of single unmanned ship,this thesis proposes a new solution to the path planning and tracking control of ship formation.The specific research work of this thesis is as follows:(1)The simulated annealing algorithm is used to optimize the repulsive function of the traditional artificial potential field method,and solve the problems that the existing improved artificial potential field method is unreachable and easy to fall into the local minimum.(2)Curve fitting is carried out on the single unmanned ship path drawn by the improved artificial potential field laws and regulations.Meanwhile,considering the ship’s kinematics and dynamics characteristics,the smoothed fitted route is taken as the reference input signal to enable the single unmanned ship to track the path: In the aspect of kinematics,the kinematics guidance law based on Extended State Observer(ESO)is designed to track the desired path and compensate the kinematic deviation caused by ocean current,and to solve the problem of underdrive of the ship.In terms of dynamics,the neural network is used to approximate the uncertainties of the dynamics subsystem,and track the expected velocity given by the kinematics control subsystem,so as to realize the compensation of internal and external disturbances and unmodeled dynamics,as well as the high-precision path planning and tracking control of the single unmanned ship.(3)On the basis of studying the path planning and tracking control of single unmanned ship,the path planning and tracking control of under-actuated unmanned ship formation is studied by using the formation structure framework combining graph theory and leaderfollowing method.The repulsion function of improved artificial potential field method is introduced kinematically,and the repulsion velocity of collision avoidance and obstacle avoidance is designed according to the repulsion function into the kinematics guidance law of unmanned ship formation.The problem of collision avoidance and obstacle avoidance between ships and obstacles in underactuated unmanned ship formation is solved,so that the leader of unmanned ship formation can track the improved artificial potential field method while planning the route.The follower and leader maintain a certain formation and avoid collision hazards.In this thesis,Matlab software is used to simulate the theoretical algorithm,and the simulation results verify the effectiveness of the ship formation path planning and tracking control based on the improved artificial potential field method.