Utilizing the Natural Dynamics of Elastic Legged Robots for Periodic Jumping Motions

This work focuses on the energy efficient control of a planar bipedal robot by using elastic elements in the joints for short-term energy storage. The considered biped exhibits three degrees of freedom per leg and each joint is equipped with a series-elastic actuator (SEA). A controller is developed to enable point foot hopping based on the spring loaded inverted pendulum template. The control design was split into the high-level rigid-body and the elastic dynamics and is validated for hopping motions by numerical simulations. A high -level reference design is proposed, which enables that the elastic system can outperform the corresponding rigid counterpart with regard to energy efficiency in stance phase by more than 50 percent.