Abstract
We have developed oscillation wing propulsion type fish robots which were modeled tuna. In this paper, we first reconstructed a Scotch-York type driving mechanism of the caudal fin. In the new driving mechanism, a 2.6kW outrunner type sensor-less brushless motor was replaced to a 5kW motor and the overall reduction ratio was reduced from 45.38 to 24.75. This new driving mechanism was tested by hanging under a surf board as a test bench. The results showed that this driving mechanism worked very well. The results, however, also showed that too much increased thrust force of the caudal fin made the large amount of the nose lifting of the surf board. It means that we could no longer examine by this test bench. So we decided to make the robot body first. We decided to make a robot body by dividing into three parts, head, body part and tail. The head can move by the synchronized motion of the tail by the different small ratio. This movable head enables the robot body made the few rigid parts mimicking the motion of the real tuna. The dorsal fin and the anal fin were set the fulcrum of the tail oscillation like tuna to reduce the transverse movement of the fulcrum. The body was made of ABS resin using 3D printer. The overall length is 1850mm. The experimental results will be reported at the conference.
