Katsuyoshi Kawaguchi*, URA Tamaki, Yosibumi Tomoda* and Heihachiro Kobayashi* * School of Marine Science and Technology, Department of Marine Mineral Resources, Tokai University 3-20-1 Orido, Shimizu, Shizuoka 424 Japan TEL:+81-543-34-0411 FAX:+81-543-34-5095
The ALBAC, a prototype of shuttle type autonomous underwater vehicle (AUV) which was designed and constructed for oceanographic measurement of water column on the way and from seabed. The ALBAC mainly consists of a body of a cylindrical pressure hull and a pair of wings which provide large lift force.By this mean, the ALBAC can move horizontally without consuming energy of batteries by gliding up to 20 degrees down from the horizontal plane. Major equipment including control actuators are installed in one cylindrical pressure hull, which has a 3-liter dry pay load space for scientific measurement devices. To control the attitude and trajectory, an actuator system displaces the location of the center of gravity longitudinally and laterally by moving a weight.
Since these apparatuses are not exposed to the sea water, the actuators are not effected by environment resulting in significantly high reliability. To ensure the total system performance, sea trials were conducted at the Suruga Bay of Japan and longitudinal and lateral motions of the vehicle were measured.
The oceanographic measurement is generally carried out being supported by a huge research ship. Since the apparatuses are hung from the deck, the ship and researchers on deck are restricted at the site. They are obliged to spend long idle time. This procedure of measurement has not been basically changed since the beginning of the history of oceanographic measurement because of hostile underwater environment.It can be said that sophisticated AUVs without an umbilical cable should be developed for efficiency and safety of measurement. Measurement of scientific data of water column, such as temperature, conductivity, pH, etc., is suitable as a mission of AUVs. This type of vehicle which descends to a specific depth and ascends back to the surface can be called a shuttle type AUV. Since such vehicles are not deeply concerned about the seabed or obstacles, the software system for the operation can be constructed in a simple architecture taking advantage of simplicity of the mission.