OPTIMIZED FUZZY CONTROL DESIGN OF AN AUTONOMOUS UNDERWATER VEHICLE

Abstract

In this study, the roll, yaw and depth fuzzy control of an Au- <br />tonomous Underwater Vehicle (AUV) are addressed. Yaw and roll angles are <br />regulated only using their errors and rates, but due to the complexity of depth <br />dynamic channel, additional pitch rate quantity is used to improve the depth <br />loop performance. The discussed AUV has four aps at the rear of the vehicle <br />as actuators. Two rule bases and membership functions based on Mamdani <br />type and Sugeno type fuzzy rule have been chosen in each loop. By invoking <br />the normalized steepest descent optimization method, the optimum values for <br />the membership function parameters are found. Though the AUV is a highly <br />nonlinear system, the simulation of the designed fuzzy logic control system <br />based on the equations of motion shows desirable behavior of the AUV spe- <br />cially when the parameters of the fuzzy membership functions are optimized.