A bio-inspired quadruped robot exploiting flexible shoulder for stable and efficient walking

While most modern-day quadruped robots crouch their limbs during the stance phase to stabilize the trunk, mammals exploit the inverted-pendulum motions of their limbs and realize both efficient and stable walking. Although the flexibility of the shoulder region of mammals is expected to contribute to reconciling the discrepancy between the forelimbs and hindlimbs for natural walking, the complex body structure makes it difficult to understand the functionality of animal morphology. In this study, we developed a simple robot model that mimics the flexibility of shoulder region in the sagittal plane, and we conducted a two-dimensional simulation. The results suggest that the flexibility of the shoulder contributes to absorbing the different motions between the forelimbs and hindlimbs.