Abstract
This paper studies a planar passive biped walker with flat feet and knees whose motion is restricted to the sagittal plane. It consists of two legs with knees connected by a frictionless hinge at the hip and two flat feet connected to each leg by a frictionless hinge at the ankle. Torsional springs are attached to the ankles. Passive walking consists of different phases such as the double-support phase and the impact phase due to the impact between the feet and the ground. It is assumed that when the knee of the swing-leg reaches full extension, the knee joint is locked. We develop a mathematical model of bipedal locomotion by using a set of differential equations describing the dynamics of walking and discrete models describing impact events. The effects of torsional spring stiffness are investigated through numerical simulations. Numerical simulations show that the planar passive biped walker with flat feet and knees can walk stably.
