Body parts of modern quadruped robots, including front legs, have few degrees of freedom. In contrast, animals such as Felidae have their forelimbs with many degrees of freedom, and achieve a variety of actions (e.g. walking, climbing, and attacking). This study aimed to understand the mechanism how the complex forelimb structure functions in realizing various movements. We focused on the forearm in the forelimb structure. Forearm rotation can adjust the posture of the palm which contacts with the environments and objects. In this paper, we developed a platform for investigating the role of the forearm during walking. Specifically, we conducted a walking simulation using a quadruped robot with anatomical features of forearm, and succeeded in reproducing the forearm behavior observed in lion walking.
