Development of Turtle-like Submersible Vehicle

Abstract

A submersible vehicle based on sea turtles was developed to investigate the possibilities of flapping fin propulsion and maneuvering. This vehicle has two forefins with two degrees of freedom, representing flapping and feathering motions. It uses them for propulsion and maneuvering. Flapping motion is realized by a combination of a stepping motor, a crank mechanism and a universal joint for each forefin; the feathering motion is realized by a servomotor for each fin. Hindfins were also equipped with one degree of freedom, and a buoyancy controller for the vehicle was designed. In experiments, this vehicle swam at 0.06 m/s when the forefin frequency was 0.53 Hz, and the maximum swimming number was 0.24 when the fin frequency was 0.35 Hz. This vehicle still presents many problems, such as limited flapping frequency. By assessing those drawbacks, this kind of vehicle might be improved and investigated for possible use.