Abstract
Many aqua robots are in practical use to investigate various aquatic animals. Caudal-fin-driven robotic fish that imitate live fish do not alarm other underwater creatures. Moreover, because such robotic fish do not use a screw propeller, they are unlikely to be entangled with water plants. In this study, two caudal-fin-driven robotic fish have been constructed with a DC brushless motor to speed up. The propulsive performance of the one-joint robotic fish and the two-joint robotic fish was investigated using several caudal fins. Two-joint robotic fish had a good performance of propulsive force 330 mN and swimming velocity 400 mm/s at the phase difference 60 degree. This robot was able to swim like live fish.
