Foot shape for passive dynamic kneed biped robot

When human walks down a slope, the center of gravity of the body leans backward to keep balance, meanwhile the friction between the heel and ground is increased. Considering this situation, a model of passive kneed biped with fixed feet is modeled in this paper. This type of passive models compensates the lost energy of collision by the potential energy when the knee is locked and the foot impacts the ground. Since different foot shapes lead to different energy lost in the heel collisions, the walking speed and energy consumption effected by various of foot shapes is discussed, and the suitable slopes for stable gait corresponding to different foot parameters is given. And these results are positive to design and debug our passive walking prototype.