A passive dynamic walking quadruped with independently movable legs

This study is intended to deal with a passive dynamic walking quadruped with independently movable legs. Since no current investigation exists about whether such robots can be created or not, we attempt to develop one in a synthetic manner. More specifically, we employed a genetic algorithm to optimize body parameters. Through this synthetic design process, we found that the robots developed can show different gaits, i.e., "walk" and "pace", which have never been realized by a conventional passive dynamic walking quadruped. We also found that the implementation of "biarticular muscles" plays an essential role to elicit stable locomotion.