Abstract
Passive biped walkers can walk down a shallow slope without actuators. This study presents a simple planar passive biped walker with flat feet and ankle springs and investigates the effect of torsional spring stiffness on the pitch motion at the ankle joints. Numerical stability studies indicated that the motion of the passive walker is stable. The physical biped walker has four legs, with each of the two legs connected so that they move identically in order to restrict the motion of the walker to the sagittal plane. Experimental results showed that the biped walker can walk in a stable manner.
