Analysis of joint stiffness in stamp of feet generalized by a two-dimensional legged robot equipped with McKibben Pneumatic Actuator

Abstract

A McKibben-type pneumatic actuator(MPA) is widely used for a robot with a simple actuator model and a simple control method. This paper aimed at to investigate the effect of its characteristics on the stability by focusing on periodic motions. We developed a 2-DOF legged robot equiped with four MPAs per leg; two MPAs arranged in antagonistic pairs around the hip and knee. We verified that the developed robot could realize a motion of stamping foot.Moreover, we analyzed the changes of the joint stiffness in the stamping motion of the developed robot. The result indicated that the joint stiffness of the hip joint depends not only on the pressure input to MPAs of the hip but also on that of the knee.