Abstract
This paper deals with an experimental study of the propulsion performance of the underwater propulsion mechanism by a self-excited flapping wing. The wing of underwater propulsion mechanism is supported elasticity in heaving direction by two elastic plates, is input driving torque in pitching direction by controlling the motor. When the wing is controlled with feedback by quantity of vibration of two elastic plates, self-excited vibration is occurred. The characteristics of the propulsion force and the side force are examined experimentally with changing drive frequency, angle amplitude of the motor, and speed that water flows. In the experiment, propulsion force and side force are examined in speed of a moving fluid 10[cm/s] in water tank. The flow of water around the wing is visualized and the structure of the vortex street is clarified. As a result, it is found that the system tends to be self-excited when the feedback gain is large and lengths of two elastic plates are 130[mm]. It is shown that the wing occurs flapping vibration combined heaving vibration and pitching vibration by self-excited drive method. It is also found that the propulsion performance of the underwater propulsion mechanism becomes high when the jet-flow occurs around the wing.
