Abstract
In the passive dynamic walking proposed by McGeer, mechanical energy lost by heel strike is restored by transporting potential energy to kinematic energy as walking down a slope. When the angle of slope becomes steep, input energy increases and bifurcation occurs. In parametric excitation walking, which is one method to realize passive dynamic-like walking on level ground, bifurcation has also been observed when walking speed is fast. Recently, Asano et al. have shown that bifurcation exerts an adverse influence upon the walking performance by using a rimless wheel model. In this paper, we apply delayed feedback control originally used in chaos control to parametric excitation walking to suppress the bifurcation. We show in numerical simulation that the proposed method makes period-two walking to period-one walking, and consequently energy efficiency is improved.
