Analysis and stabilization of the passive walking robot via analogy with the Phase Locked Loop circuits

Recently many walking robots are developed, and almost all the researches adopt the model-based control. However the researches also adopt other ideas based on the dynamics-based control to decrease their energy consumption or to absorb the impact shock of contacting, etc. So it seems important and valuable for the conventional walking robot control to import the ideas based on the dynamics. On the other hand, we focus the passive dynamic walking robots which walk only by the dynamics. If the principle of the robot system is analyzed and elucidated, we are able to apply the essence of the system to the conventional walking robot control, and also contribute the performance gain. In this paper we analyze the behavior of the passive dynamic walking robot system via analogy between the phase locked loop circuit and the passive walking robot system, and we ascertain that both of them bifurcate and show chaotic behavior on the same condition. Then we propose the method to stabilize the bifurcated gait