RIASSUNTO
ABSTRACT
This paper describes the experimental results on the guidance and control of an underwater vehicle equipped with 2 pairs of the oscillating fins in water currents. At first, we demonstrated that the vehicle has the performance of surveying the surface of the circular cylinder in water currents. Next, we remodeled the alignment of the rear mechanical pectoral fins to increase the maneuverability of the vehicle in water currents.
INTRODUCTION
The existing underwater vehicles, the motion of which is controlled by thrusters and wings, exhibit poor performance not only in hovering and turning in a vertical or horizontal plane over intricate seabed terrain in strong currents, but also in dexterous manipulation under floating conditions. The study of locomotion of aquatic animals can provide new insight into the maneuverability and stabilization for underwater vehicles. This paper focuses on biomimesis of aquatic animals as a source for developing a new device for maneuvering underwater vehicles.
Many previous studies have focused on fish fins and their motion as an axial undulation fin oscillation for propulsion (Barrett et al., 1999; Kumph et al., 1999; Triantafyllou et al., 2000; Anderson et al., 2001; Nakashima et al., 2002). However, due to the prevalent use of screw-type thrusters, application of the axial undulation and fin oscillation as the main thruster for underwater vehicles is not straightforward. A major drawback of these screw-type thrusters is the sudden generation of a thrust force when the underwater vehicles is hovering, which leads to imprecise control of the position and attitude of the vehicle and of its manipulators. Because many types of fish use oscillating pectoral fins for their maneuvers at low swimming speeds (Lindsey, 1978), utilization of the pectoral fin motion could possibly overcome the drawbacks of the screw-type thrusters.