“Cheap” Underwater Locomotion: Morphological Properties and Behavioral Diversity

Toward adaptive underwater locomotion, this paper presents the experimental results of a fish-like swimming robot that we have newly developed. By using motor control with only one degree of freedom, this robot exhibits surprisingly rich behavioral diversity in three dimensional underwater environment. This paper focuses on some of the behavior variations this robot exhibits, i.e. forward, turning, and vertical movement, which are required for the underwater three dimensional navigation. The visual behavior analysis shows that, even though there is only one motor, these behavior are possible because this robot exploits the unique interaction with the environment derived from the morphological properties of the robot. Moreover, some of the behaviors demonstrated by this robot have a considerable similarity to those of biological systems, which would also contribute to understand the adaptive behavior of animals. Based on the experimental results, we speculate further issue on “cheap” underwater locomotion.