半円足の転がり効果を利用した劣駆動仮想受動歩行―（ＩＩ）性能解析と冗長モデルへの拡張―

Abstract

This paper investigates what effect semicircular feet had on dynamic bipedal walking. It has been clarified in paper (I) that underactuated virtual passive dynamic walking can be realized by using the rolling effect, which acts as the ankle-joint torque virtually. This paper (II) then studies the rolling effect on the gait performances in detail through theoretical investigations and numerical analyses. We first perform parameter studies, and confirm that a suitable choice of the foot radius increases walking speed effectively. It is then theoretically clarified that increasing walking speed is achieved not by the rolling effect during the single support phase but by reducing the energy-dissipation due to heel-strike collisions. It is also confirmed that mass of the leg is necessary to drive the robot's center of mass in the walking direction. Furthermore, extension to redundant models with knee-joints is discussed.