A 2-D Passive-Dynamic-Running Biped With Elastic Elements

This is the first study of a real physical kneed bipedal robot that exhibits passive-dynamic running (PDR), i.e., a bipedal gait with a flight phase in a device without an actuator. By carefully designing the properties of the elastic elements implemented into the hip joints and the stance legs in this device, we achieved a stable PDR consisting of 36 steps. The main contribution of this paper is the demonstration of PDR in the real world, which fully exploits the elastic mechanical properties.