Ankle and Foot Mechanism Mimicking Joint Stiffness and Following Motion Based on Human

Abstract

While running, humans use the stiffness of the knee and ankle joint of the leg. Mimicking this motion can improve the output power and performance of humanoid robots. It also offers the possibility of clarifying running in humans, from an engineering perspective, by mimicking other characteristics of an ankle joint. In this paper, we design an ankle and foot mechanism that mimics human’s characteristics, such as joint stiffness in the direction of pitch, and following the floor surface in the direction of roll upon landing for stabilization. To mimic these characteristics, our ankle joint mechanism consisted of CFRP (Carbon Fiber Reinforced Plastic)-laminated leaf springs implemented on the foot of the robot for a deflection in direction of pitch and a twist in the direction of the roll. We ensured that the ankle joint can follow the ground in the direction of roll at landing in a hopping experiment.