Research On Path Planning Of Wave Glider Considering The Influence Of Wave And Current

The Wave Glider is a new type of autonomous mobile observation platform,which can utilize wave energy to generate forward momentum and have a strong endurance and selfcontrol ability.Reasonable route planning is the premise to ensure that Wave Glider can complete the offshore works tasks accurately and efficiently.The Wave Glider is driven by wave force rather than disturbed by wave force,which is different from the traditional Unmanned Surface Vehicle.We should fully understand the effects of the wave height,period and other parameters on Wave Glider forward motion.Driven by the wave,the speed of the Wave Glider is slow and the ocean current has a great influence on its motion.Especially,Wave Glider will be out of control in the face of strong current.Considering wave driving and current interference,we design a path planning method that can focus on the characteristics of navigation.In order to solve the problem of Wave Glider path planning,this paper analyzed the motion mechanism and kinetics model of the Wave Glider,and used data analysis and numerical calculation to analyze respectively the influence of ocean current,wave and wind in the ocean environments on the motion of Wave Glider.,and clarified the importance of ocean current and wave in the path planning of the Wave Glider.In view of the different ocean environments that Wave Glider may encounter,this paper used grid algorithm to store the sizes and directions of ocean current,heights and periods of wave and obstacles into the grid information to establish the static or dynamic ocean environment model.Aiming at the problem that wave gliders are affected by wave currents,this paper put forward a kind of path search algorithm,considering Wave Glider working in static wave and current environment,which is based on improved SAS algorithm.The driving velocity of the Wave Glider was calculated by the wave parameters and coupled with the current velocity to determine the expansion direction of the adjacent nodes.By combining the artificial potential field theory to consider navigation safety,this paper designed the time optimal cost function to search the global path.On this basis,by using D*algorithm,a dynamic path planning search algorithm considering dynamic wave and current environment was proposed.Based on the improved SAS algorithm,during the search process,if the original path is not optimal due to time changes in the environment,the dynamic global path search would be completed by reprogramming at the change node.Considering the navigability of the planned path,the method of gradient descent was used for iteration to obtain smooth path.Simulation experiments of path search in static and dynamic environments were designed respectively to verify the effectiveness of the search algorithm.Finally,basing on the improved SAS algorithm and the improved D*algorithm,this paper put forward Wave Glider path planning method considering the static or dynamic wave and current environment,and combination of ocean environmental forecasting.The simulation experiments verified the feasibility of planning method.The simulation results show that the Wave Glider path planning method can apply to different ocean environments,and to determine target accessibility.In the reachable time,we can plan the time-optimal route considering that Wave Glider is driven by wave and is disturbed by ocean current.And it is proved that the path planning method for Wave Glider is feasible and effective.