Abstract
There are many researches on biped passive dynamic walking. As the results, many interesting results have been discovered. For example, the stability or the bifurcation phenomenons of P.D are discussed. But nobody has shown the existence of the 4-legged passive dynamic walking. In this paper, we developed a 4-legged passive dynamic walking machine and carried out the experiments. As the result, we show the existence of the phenomenon of 4-legged passive dynamic walking. Also, 6-legged passive dynamic walking will be considered.