Abstract:This paper investigates a compasslike passive dynamic walking model. Horizontal and vertical DOFs (degrees of freedom) are designed at the stance foot to calculate the normal and friction forces, and describe the pushoff and heelstrike processes. The passive dynamic walking gaits are calculated, and the local and global stabilities are analyzed. The results show that the walking gait is stable when the maximal absolute eigenvalue of the Jacobian is within the unit circle and the initial conditions of the walking gait is within the basin of attraction. These studies can not only provide guidance for understanding the motion mechanism of biped walking, but also help us for designing stable and efficient biped robot. For example, mechanical parameters improvement and efficient control strategy design.