Exciting passive dynamics in a versatile bipedal robot

Dynamic bipedal robots, which are capable of versatile behaviour, are rare. Most bipedal robots are either versatile and static or dynamic and limited to specific gaits. Over the last twenty years the bio-inspired spring mass model became a versatile template for bipedal walking and running gaits with many studies motivated by its high potential for versatile robot locomotion. However the characteristic dynamics have not yet been demonstrated with human size robots. We show that we can reproduce the dynamics of this versatile template for locomotion in a human-size biped utilizing its specifically designed natural dynamics. Spring mass walking with characteristic double humped force profiles is demonstrated over a range of speeds. Using the same controller, the robot exhibits grounded running, walks over steps, and in an natural outdoor environment. The robot is an important step towards bipedal machines capable to compete with animals in terms of efficiency, robustness and versatility and enables a better understanding of fundamental biological movement principles.