Development of Turtle-like Submersible Vehicle

Abstract

A submergence vehicle based on sea turtles was developed. This vehicle has two fore fins with two degrees of freedom; flapping and feathering motions, and flaps for propulsion and/or maneuvering. Hind fins were also equipped, and a buoyancy controller for the vehicle was designed. In experiments this vehicle swam at 0.06 m/s when fore fin frequency was 0.53 Hz. Performance of the vehicle was also estimated using the blade element theory. By applying the theory against our vehicle, its velocity is estimated as around 0.18 m/s when fin frequency is 0.53 Hz. Two of the reasons of difference between the theory and the experiment are that the theory ignores wing-tip loss so that it gives the higher estimation than expected, and that the vehicle could not perform its full potential at the experiment. This vehicle still has many problems, and by taking measure of them the vehicle may be used to estimate the possibility of this kind of vehicles.