Facilitating multi-modal locomotion in a quadruped robot utilizing passive oscillation of the spine structure

An important topic in robotics is the design of a robot body using passive mechanical properties, such as viscoelasticity, to obtain energy-efficient locomotion at low computational costs. To achieve this aim, this study examines adopting a spinal structure with variable viscoelasticity and multiple joints. In order to investigate the effect of this spinal structure, a physical model of the spinal structure and a quadruped robot incorporating this design were developed, and the relationship between the gait pattern of the legs of the robot and viscoelasticity as a source of passive oscillation of the spinal structure was observed. The experimental results indicate that there are several interactions between the gait pattern and the viscoelasticity that can achieve one of various types of successful locomotion. These results suggest that the proposed spinal structure is a suitable body design for facilitating multi-modal locomotion at low computational costs.