Path Planning And Path Tracking For Autonomous Underwater Vehicles

Autonomous Underwater Vehicle(AUV) is a kind of important underwater equipment. Its research has a profound economic meaning and is imminently needed because of military and politics reasons. The requirement of its ability to take corresponding measures in accordance with the environmental changes in its moving courses has become higher and higher. Autonomous navigation is a fundamental requirement for AUV. As one of key technology for autonomous navigation, path planning means that AUV can find an optimal path from starting position and end position in an obstacles environment and other constraint conditions, and is able to implement path tracking control for AUV. To resolve the practical problems in the national project (863), in the thesis, investigation to some key technology for autonomous navigation are presented. The focus of this paper can be divided into two parts: path planning and path tracking control for AUV.Firstly, this paper introduces the research status on AUV at home and abroad, application prospects, development trends and the sources of this task, research significance. Secondly, this paper studies the AUV dynamics equations and kinematics model, which is indispensable to make path planning rules and tracking schemes. Lastly, this paper discusses all kinds of global and local path planning methods and characteristics, including geometric method, artificial potential field method, genetic algorithm and so on. On this basis, the global path planning in the ocean environment using Fast Marching Method (FMM) based on grid environment is studied in this paper. The method provides the feasibility proposal for AUV global path planning in the ocean environment, and FMM principle and operation process are also discussed in detail. In this paper, programming and simulation based on Fast Marching Method (FMM) is finished. The result proved that Fast Marching Method is known to be efficient for finding cost optimal path because of its simple implementation, fast convergence and high reliability, and meet the system real-time requirement. On the basis of path planning, this paper also discussed AUV path tracking control and implementation. According to the AUV kinematics and dynamic model, path tracking control technology based on PID controller is studied, also, respectively taking tracking research on straight-line path,circle path and complex path in Simulink system. Meanwhile the result of path tracking with different ocean current is considered. The experiment result shows the tracking control method is fast, accurate and global stable properties. Path planning and tracking control system in this paper gives a satisfactory result after experiment.