Design Of Unmanned Surface Vehicle For Ocean Environment Exploration And Path Planning

The technology of ocean environment exploration is an important component of the ocean environment resource development. And it is an important method to monitor the real-time environment information near the coast, detect resources and prevent the ocean disaster. And it has great significance for the country's economy and security. This thesis focuses on the research of a design of intelligent unmanned surface vehicle which will be used for ocean environment resource exploration. This research includes vehicle's system design and path planning.Firstly, this thesis introduces the situation of unmanned surface vehicle's development status at home and abroad and brings up the idea of vehicle's system design. With the embedded Linux operation system, this system adopts the ARM microprocessor. This system includes four modules, GPS, sensor, image and GPRS. The GPS module is used to gain the vehicle's location information, the sensor module collects the information of the obstacles, the image module collects the information of ocean environment and the GPRS module sends these information back to the server for further research.Secondly, this thesis introduces some popular methods for path planning, such as the global path planning methods, including artificial potential field, topology, visual graph and free-space method; including the local path planning methods, neural network, fuzzy logic and genetic algorithm and analyzes the advantages and weakpoints of these methods.Thirdly, this thesis explains how to avoid obstacles based on sonar sensor. Two kinds of coordinate systems, the sonar system and the stationary system, are built for the location of obstacles and the transformation between them is explained. It states how to avoid the obstacles from frontage and sides and the means of confirming the safe obstacles avoidence distance. Then two kinds of functions are proposed to figure out the moving direction under this avoidant pattern.Finally, a new way of optimizing the path using improved potential field approach is proposed. The original potential field is used into the unmanned surface vehicle's path planning. The effect of the sea wave is taken into account to the forces analysis and the new model is bulit. Then simulation experiments are taken to prove the algorithm. Through simulation experiments the flaws of original potential field can also be found, and the improved algorithm is proposed to solve this problem.The new simulation experiments can verify the improved potential field and make sure the vehicle can arrive at the goal even when the goal is highly close to the obstacle.