Analysis of dynamics of passive walking from storage energy and supply rate

Passive walking robot can dynamically walk down with natural gait by the interaction between walker\´s dynamics and environment (slope). This robot exhibits a stable limit cycle and its gait bifurcates for larger slope. Analysis of dynamics of passive walking may be useful for understanding human locomotion and development of walking machine. In this paper, we analyze dynamics of passive walking from the aspect of "storage energy" and "supply rate". We also demonstrate that a stable fixed point becomes unstable when 1-periodic gait turns 2-periodic.