The Effect of Semicircular Feet on Energy Dissipation by Heel-strike in Dynamic Biped Locomotion

This paper investigates the effect of semicircular feet on dynamic bipedal walking. It has been clarified by Asano and Luo (2006) that underactuated virtual passive dynamic walking can be realized by using the rolling effect, which acts as the ankle-joint torque virtually. It has been also shown that, throughout parameter studies, the rolling effect dramatically increases the stable domain of limit cycles. Now that the effect of semicircular feet during stance phase has been discussed, this paper then focuses the effect on mechanical energy dissipation by heel-strike. It is theoretically clarified that, through modeling and analysis of an inelastic collision, increasing walking speed is achieved not by the rolling effect during stance phase but by the effect of reducing mechanical energy dissipation by heel-strike.