Experimental Validation of Passive Monopedal Hopping Mechanism

Passive dynamic locomotion, which relies solely on the interaction between the body and the environment, is being explored as an energy-efficient method of movement. The authors’ laboratory investigates passive hopping mechanisms that do not require actuators or sensors. In previous studies, it was demonstrated that an asymptotically stable limit cycle exists in the leg dynamics of a passive hopping model with constrained torso posture. In this study, a monopedal passive hopping robot with constrained torso posture was constructed to validate the existence of the limit cycle. The leg dynamics were evaluated by comparing the trajectories of the model and robot. The results revealed that the leg dynamics of the simulation model represent those of the physical robot. Furthermore, robustness to step disturbances confirmed the validity of leg dynamics.