This paper describes an autonomous underwater vehicle (AUV) with fuzzy controller and acoustic communication system. Our AUV is compact and light in weight by employing variable vector (VARIVEC) propeller and compact controller using sophisticated logic circuits. The AUV is autonomously controlled by utilizing the electronic compass, collision avoidance sonar, depth sensor and GPS receiver unit. A fuzzy logic controller has designed and examined in autonomous navigation. Experimental results indicate that our AUV can move along the targeted path and hold the desired position and the depth.
The scientific investigations of marine environment often require the use of underwater vehicles to perform exploration, survey, monitoring, and data collection tasks. We are primarily concerned with daily marine measurements in the closed sea areas like the Isahaya Bay and the Ohmura Bay in Nagasaki prefecture, Japan. Usually underwater vehicle are equipped with many thrusters. The thruster control mechanism is complicated and this takes a larger weight ratio, making the AUV larger and heavier (Ura, 1997). We developed the VARIVEC propeller (Hoshino, 1991) system utilizing the radio control helicopter elements, which are swash plate and DC servomotors. VARIVEC propeller can generate six components including thrust, lateral force and moment by changing periodically the blade angel of the propeller during one revolution. We developed a compact and light AUV by employing VARIVEC propeller and a compact control system using sophisticated logic circuits. A compact AUV is capable of performing several challenging functions and enables it to be used by a limited number of persons. For the daily measuring tasks, a small AUV will be necessary for efficient exploration and investigation of a wide range of a sea. We have implemented three modules, which include the receiver control module, the sensor control module and the propeller control module.