The Reaserch Of The Fuzzy Control Algorithm For Underwater Glider Control System

Ocean has a great exploration potential with large reserves. According to the requirements of sail ability on Underwater Glider, this thesis emphasizes on the research of the motion process, DC servo motor fuzzy PID control algorithm design and the underwater glider collision avoidance research.In the part of motion analysis, the motion mechanism and energy efficiency in gliding are researched here. The established dynamic equilibrium equation based on the force analysis shows that the outside bladder would be better fixed close to the glider stern, thus the displacement of the buoyancy center changed by the bladder volume change will have sound effect on the pitch angle adjustment. The energy exchange analysis indicates that gliding energy efficiency is dependant on the lift drag ratio of the wings and gliding angle of the hull. Through the calculation in this thesis, it can be concluded that enhancing the lift drag ratio can largely improve the energy efficiency when the gliding angle is in the range of 10 to 40 degree, and when lift drag ratio is fixed, there exists a special gliding angle for the maximum of the efficiency, which provides theoretical basis for the design of operating parameters.In this paper, the overall underwater glider control system design is given, forcusing on one of the attitude control of navigation. For non-linear, parameter uncertainty and the location follow-up system requirements for real-time and without overshoot, this paper puts forward a fuzzy online self-tuning PID parameters of the control algorithm, which speeds up the system response speed, reduces the overshoot and improves the system steady-state accuracy. At the same time, the robustness of the system will be improved. And the system satisfies underwater robot glider attitude angle positioning accuracy requirements.This paper proposes a new heuristic search technique for obstacle avoidance of Autonomous Underwater Vehicles (AUVs) that are equipped with a looking-ahead obstacle-avoidance sonar. The fuzzy relation between the sonar sections and the properties of a real-time environment is used as a core concept. The Lukasiewicz fuzzy implication operator is used in Bandler and Kohout's Triangle Subproduct to calculate the relationship between the fuzzy relation and its transposed relation. This product relation the reveals the characteristics and interrelationships of the sonar sections. A direction of the sonar section that has good characteristics is selected as the successive heading for obstacle avoidance of AUVs. First, an underwater glider simplified kinematics model is established in this paper,and experimentizes with Matlab(Simulink) and VC++. The simulation results clearly demonstrate that the heuristic search technique enables AUVs to navigate safely through the obstacle to the goal with the optimal path.