3D Dynamic Biped Walker with Flat Feet and Ankle Springs: Passive Gait Analysis and Extension to Active Walking

A ZMP pattern of passive walker RW03 In the last two decades, passive dynamic walking (PDW) has attracted considerable research attention. The assumption that biped walking is based on PDW is now widely accepted. PDW bipeds change their gait to adapt to changes in body configuration and environment, and their efficiency is extremely high. PDW is generally difficult to realize because it lacks robustness. This means, for one thing, that biped walkers capable of PDW must be designed carefully. Once realized, however, the PDW bipeds are expected to have a suitable configuration for biped walking. This study then aims to analyze the fundamental properties of 3D PDW with flat soles and ankle springs and to use these properties to extend it to a horizontal surface. First, we develop a stable and relatively robust 3D PDW biped that has flat soles and ankle springs. Some sensors are implemented in order to measure the posture and the ZMP trajectory. Next, we investigate the relationship between its gait and the CoM position of each leg. We then attach a ballast to the leg to change the CoM, which effectively results in walking stability. Finally, a 3D active biped, whose knees consist of telescopic joints, is developed based on the 3D PDW biped.