Research On Unmanned Ship Path Planning And Control Algorithm Based On Specific Observation Targets

With the continuous development of modern science and technology,various unmanned devices emerge one after another.Unmanned surface vehicle(USV),as a future marine vehicle and operating platform,has important research significance for marine development and application;USV use machines to replace people to complete control strategies and are now in the ocean.Water quality monitoring,marine surveying and other fields are put into use;however,due to the limitations of different operational tasks and path planning algorithms,such USV are unable to perform close-range inspection of an observation target within a specified sea area within a specified time period as required by this paper.Observing tasks;for this purpose,this paper will conduct in-depth research on the path planning and path tracking control technology of USV for observational tasks.In this paper,the following research work is carried out for the path planning and path tracking control technology of USV:(1)In order to complete the design of the unmanned experimental platform control system,this paper develops the overall scheme of the unmanned experimental platform control system based on the existing design experience;for the design of the unmanned experimental platform hardware control system,this paper is based on the basic functions to be realized by the unmanned experimental platform.To analyze the functional requirements of the hardware control system of the unmanned experimental platform;to design the software control system of the unmanned experimental platform,this paper analyzes the basic functions of the software that the unmanned experimental platform must have,and separately develops the upper computer,the lower computer main controller,and the lower computer.Controller control flow;in order to design the USV path tracking control algorithm and verify its effectiveness,this paper analyzes the force situation during the USV motion and establishes the mathematical model of USV motion for the following USV path tracking.The basis of control algorithm research.(2)In order to complete the observation task for a specific observation target,this paper studies the USV global path planning method in the observation mission environment.In order to describe the USV and obstacles in the mission environment through mathematical model,this paper establishes the observation work task environment coordinate system;in order to simplify the path planning algorithm derivation process and ensure the absolute safety of the USV,this paper rounds the obstacles.Shape enveloping and expansion treatment;in order to complete the close observation mission of the target ship,this paper preliminarily plans the global path of the USV operation task;considering the impact of the current on the target ship position,this paper is based on the sensor information of the USV.The global path is corrected;in order to avoid the planned global path avoiding the static obstacles in the environment,the artificial potential field method is used to plan the path of the obstacle;in order to solve the traditional artificial potential field method,there is a local minimum in the planning process.In this paper,the traditional artificial potential field method is improved by adding virtual target points.Finally,a simulation experiment model based on improved artificial potential field method is established.The simulation experiment proves that the improved artificial potential field method is designed to solve the local problem.The minimum point and the effectiveness of avoiding random distribution obstacles.(3)In order to enable USV to avoid the dynamic obstacles existing at sea,this paper comprehensively considers the dynamic performance and obstacle characteristics of USV,and designs a local path planning algorithm to ensure the absolute safety of USV at sea.In order to facilitate the derivation of the local path planning algorithm,this paper establishes a local path planning environment model.In order to avoid collision accidents caused by different obstacle avoidance strategies between USV and obstacles,this paper studies and summarizes the International Maritime Obstacle Avoidance Rules;for the collision of USV and obstacles,this paper judges them based on the principle of speed obstacles and deduces the feasible speed range of USV avoiding obstacles;To the USV’s own motion performance,this paper constrains the feasible speed region according to the speed range that the USV can reach in a certain period of time;choose the optimal solution from the feasible speed region as the avoidance of the USV.In this paper,the evaluation function is used to evaluate the USV speed.Finally,the local path planning model based on the principle of speed barrier is established.The effectiveness of the local path planning algorithm based on the speed barrier principle is verified by simulation experiments.(4)In order to enable the USV to travel according to the planned route and ensure the path tracking accuracy meets the mission requirements,this paper designs an USV indirect path tracking control algorithm based on the LOS method.In order to enable the USV to accurately track the planned path,this paper designs the linear and circular path guidance method of the USV based on the LOS method;considering the influence of sea wave interference,modeling error and speed change in the actual working environment of the USV In this paper,the mathematical model of USV is further derived,and the nonlinear mathematical model of USV with uncertainties is obtained.In order to improve the accuracy of USV path tracking control,this paper designs the USV sliding mode heading based on the uncertainty upper bound.The controller is verified by the sinusoidal contrast simulation experiment.The sliding mode heading controller designed in this paper has better control effect.Finally,the LOS-based guidance method is combined with the USV sliding mode heading controller to establish the USV path tracking control model;the effectiveness of the USV indirect path tracking control algorithm designed in this paper is verified by simulation experiments.