Design of a Fuzzy Controller for Underwater Vehicles to Avoid Moving Obstacles

This paper presents a robust fuzzy controller for an underwater vehicle to avoid moving obstacles. Dynamics of underwater vehicles is explained, its details are discussed and the equations of underwater vehicles motion are mentioned. Then a simple fuzzy controller that gets information from looking-ahead sonar is introduced. Using the sonar information, the fuzzy controller determines speed and attack angle of underwater vehicle movement. The robustness and efficiency of fuzzy controller performance is guaranteed, by suitable definitions of input and output variables. With lack of generality, some restrictions are considered for the obstacle movement, to simplify the simulation performance. The mission is defined as to navigate the underwater vehicle toward a desired goal without collision with moving or static obstacles. The intelligent structure of the fuzzy controller, results in a spectacular capability in avoiding obstacles. The simulation results clearly demonstrate that the robust fuzzy controller enables underwater vehicle to navigate safely, by avoiding the obstacles, to the goal with the desired path.