Gait analysis for the development of the biped robot foot structure

The flexibility and deformations of the human plantar arch are among the most important issues when walking. Especially, the efficiency and mechanisms of the plantar arch should be demonstrated because there are few beings that have such a complex structure, in particular bipeds. On the other hand, nowadays biped robots have a too simple foot structure and they cannot walk like human in particular on the irregular grounds. If biped robots had flexible feet, its walk could be improved by increasing the area of contact with the ground in spite of the irregular ground. In order to apply the human plantar arch to biped robots, we analyzed the human gait against the asperity. Our approach is mechanical. We measured the human gait when wearing a mechanical foot made to imitate the human plantar arch. We compared the dynamics calculation data with different conditions of the mechanical foot. The results made obvious that a flexible foot helps in decreasing the torque at the ankle, knee and hip, however it is necessary to change the elasticity during the gait cycle in order to mimic the characteristics of the human plantar arch. We could indicate the efficiency of the elastic change against the irregular grounds quantitatively throughout the experiment.