Physical Explication and Realization of the Turning Motion of a Cat by Analysis and Experiment Using a Robot Cat
Takashi Kawamura, Kazuo Yamafuji and Tsuyoshi Kobayashi
Department of Mechanical and Control Engineering, University of Electro-Communications 1-5-1 Chofugaoka, Chofu Tokyo, 182 Japan
Over turning motion of a cat at free fall in the air was investigated analytically and experimentally. Firstly, a live cat was modeled by a double circular column jointed with a spine at the one end of each column. And the dynamic characteristics of the model was analyzed based on the law of conservation of angular momentum. Then computer simulation was carried out. The results due to the simulation coincide well with those derived by the analysis, and validity of the modeling was shown. And a ROBOT CAT composed of a double circular column and a new type of backbone was developed in order to execute turning motion at free fall just like a cat. The robot successfully performed the complete overturning (180 degrees rotation) from the upside-down posture within 0.6 second. Therefore, the robot can change its posture to land on its feet if released from about 1.8m height quite upside-down.