Research Of Path Planning For Unmanned Surface Vehicle In Complex Water Environment

Unmanned Surface Vehicle can sail autonomously and complete the corresponding tasks in the ocean environment.Effective path planning algorithm is the key to autonomous navigation.In this paper,we consider the influence of wind and current resistance on the path planning of the Unmanned Surface Vehicle from the actual situation of unmanned boat navigation and propose an improvement method to find the optimal path in the three aspects of path length,navigation time and navigation safety by comprehensive evaluations.The specific research contents are as follows:(1)Considering the safety problem of the Unmanned Surface Vehicle when sailing in a complex environment,the method of reconstructing the Dynamic Window Approach(DWA)motion model is proposed,and the propeller reversal is used to realize the safety braking setting in order to improve the safety of the Unmanned Surface Vehicle sailing.The force analysis is carried out according to the wind and water resistance suffered by the Unmanned Surface Vehicle during navigation,and the instantaneous deflection angle is obtained to derive the heading angle formula that can be applied to the motion model of DWA algorithm.The effectiveness of the improved algorithm is confirmed by comparing the simulation trajectory and correction angle error before and after the improved algorithm under different wind speed conditions.(2)In order to optimize the path trajectory of Unmanned Surface Vehicle navigation under the premise of ensuring safety,the method of improving the evaluation function of DWA algorithm is proposed and combined with A* algorithm with global guidance features to jointly complete the overall path planning.In this paper,on the basis of the original evaluation function,the influence of wind condition factor on the evaluation function is added,and the speed evaluation function is constrained by adding the wind condition coefficient k.The simulation results show that in a certain wind speed range,the relative path length and sailing time are optimized by 4.12% and 7.66%,respectively,and the shortest distance from the obstacle is increased,which proves that the improved algorithm can plan a better quality path trajectory improve the navigation efficiency of the Unmanned Surface Vehicle.(3)Build the Unmanned Surface Vehicle autonomous navigation system and virtual water environment based on the ROS platform,add wind,wave and buoyancy plug-ins,and customize the water surface obstacles.Load the improved algorithm into the 3D model of Unmanned Surface Vehicle and verify it.The simulation results confirm that the proposed improved algorithm has good path planning effect in the virtual water environment,which is consistent with the simulation results of MATLAB software,and the Unmanned Surface Vehicle did not collide with obstacles during the navigation.