Terrain Negotiation of a Compliant Biped Robot Driven by Antagonistic Artificial Muscles

Humans can negotiate various classes of terrain and realize adaptive bipedal walking, which is difficult for existing biped robots driven by electric motors. In this paper, a biped robot driven by antagonistic artificial muscles is developed that can negotiate several classes of terrain. The antagonistic muscles along with a simple control scheme can realize joint compliance without a time-delay. Not only does the compliance adapt the robot to terrain changes, but it also enables the robot to sense the terrain since the walking behavior is a result of the interaction between the dynamics of the robot body and the terrain. Experimental results demonstrate that the walking cycle changes according to joint compliance and the class of terrain. Utilizing the relationship between the two, the robot can regulate its walking cycle by changing its joint compliance. The compliance by such antagonistic muscles is a promising solution for realizing adaptive bipedal walking.