FUZZY-LOGIC CONTROL OF AN AUTONOMOUS UNDERWATER VEHICLE

Applications of fuzzy logic for both the low- and high-level control of an Autonomous Underwater Vehicle (AUV) am described. A six degree-of-freedom flight control system for the Ocean Voyager has been developed where heading, pitch, and depth am controlled simultaneously by three separate single axis fuzzy logic controllers. A fuzzily constrained integrator compensates for frictional effects and setpoint error. A nonlinear simulation model is used both to analyze the behavior of the fuzzy logic controllers and to calibrate the rules. Ongoing work with cell state space techniques to optimize performance is described. In addition, a docking controller for the Ocean Voyager based on a fuzzy algorithm is described. The fuzzy rule base recursively drives the vehicle towards intermediate fuzzy goals that become more precise as the final target is approached. Docking proceeds as long as the AUV remains in a funnel of acceptable intermediate positions.