A study on effect of two-arch structure of foot for biped robots

The arch structure of human foot plays important roles such as impact absorption for bipedal locomotion. In this paper, the two-arch structure is introduced into the foot model of biped robot. Using a flat foot model, a one-arch foot model and the two-arch foot model, simulations of robot motion are performed by ODE and effects of the arch structure are verified. When the inner arch was softer than the outer arch like human, the robot motion such that the COG returns to inner direction was observed. It was verified that the property of the returning motion was determined by the difference of elasticities between the inner arch and the outer arch, and the property of motion in the frontal direction was determined by the average of elasticities.