Abstract
Fish type underwater robots have a lot of possibilities such as good mobility and high efficiency. Most of the fish type robots developed up to now have complicated mechanisms with complicated motion control. It results in that the structure and the movement of robots are different from those of fishes. The purpose of our work is to develop creaturelike flexible underwater robots by using piezoelectric fiber composite. Compared with conventional artificial muscular underwater robots, powerful underwater robots with a very simple structure can be composed by the piezoelectric fiber composite. This paper describes the development of a flexible underwater robot with pectoral fin propulsion like ray and mode shape propulsion of structural vibration, which can generate various movements.