STUDY ON TURNING PERFORMANCE OF A FISH ROBOT

Underwater robots are widely used in the fields of ocean development, ocean investigation and marine environmental protection. Autonomous underwater robots are planed, and several robots have been already developed. They need higher efficiency of propulsive performance and good dynamics performance. On the other hand, it is well known that several kinds of fish have a good ability of turning and acceleration. If the underwater robot that can simulate a fishlike locomotion is developed, it is considered that the robot has dynamics performance similar to fish. The aim of this study is to develop a fish mimetic underwater robot with good dynamics performance. At first, we discussed turning modes for the fish robot that uses tail swing. Based on the discussion, the prototype fish robot, which has 340 mm body length, was developed. Just after manufacturing, swimming speed at straight propulsion was measured. Next, we measured turning performance with the suggested turning modes. As the result, it was confirmed that frequency, amplitude and leaning of the tail affect the turning performance. Still more, we made sure that the prototype fish robot turned quickly from straight propulsion and stationary state.