Variable Stiffness Mechanism for Shoulder Hammock Structure in Quadruped Robot

Abstract

Cursorial mammals (e.g., cat and horse) have flexible connections between the forelimb and the trunk and realize both rotational and translational motions of the scapula in the sagittal plane. Biological studies suggest that the muscular activities around the shoulder depending on gait patterns. To understand the control mechanism underlying adaptive behavior of the cursorial mammals, this study develop a quadruped robot mimicking the flexibilities of the shoulder regions of the cursorial mammals. Results of weight bearing experiments show that a proposed variable stiffness mechanism in the shoulder region can change stiffness of the shoulder region against the vatical load.