Unified bipedal gait for walking and running by dynamics-based virtual holonomic constraint in PDAC

Abstract

Conventional humanoids have achieved walking and running by independent controllers, even though a transition between these independent motions should be added to connect them while ensuring stability. In contrast, human selects walking/running at low/high speed in terms of energy efficiency, and transits between them naturally. This fact implies that human gait shares the inherent controller among walking and running despite their quite different appearances. Hence, we propose a "unified bipedal gait," which includes walking, running, and the transition. The unified bipedal gait has the inherent controller: passive dynamic autonomous control (PDAC) with a damping and spring loaded inverted pendulum (D-SLIP) model. The PDAC constrains the humanoid natural dynamics by a virtual holonomic constraint (VHC) that degenerates the natural manifold of the states for stabilization. Compliance in the D-SLIP is capable to yield the required characteristics of walking/running: low/high compliant legs for walking/running. Thus, a novel VHC is designed to extract the required characteristics of walking/running from the D-SLIP dynamics and form the proper manifold. As a result, we achieved the unified bipedal gait that bifurcates to walking and running via the natural transition. The high energy efficiency was confirmed in this unified bipedal gait at any gait speed.

Multimodal bipedal locomotion generation with passive dynamics via deep reinforcement learning

“…However, despite the importance of passive dynamics in bipedal locomotion control, it has not been sufficiently investigated in previous bipedal walking and running robots (Hodgins, 1991 ; Kwon and Park, 2003 ; Nagasaka et al, 2004 ; Tajima et al, 2009 ; Sreenath et al, 2013 ; Kobayashi et al, 2016 ; Siekmann et al, 2021 ). There are two possible reasons for this: (1) Robots with passive joints are more difficult to control than fully actuated robots because there is less scope for the control system to intervene in motion generation.…”

Implementation and Integration of Fuzzy Algorithms for Descending Stair of KMEI Humanoid Robot

“…There are two approaches for biped modeling: distributed mass model and real parameter simplified model. The detail information form of dynamic parameters of the robot is discussed in [3]. The robot generates 3D walking motions ascertains dynamically by using linear constraints with approach efficient MPC, and successfully during walking on uneven terrains also walking on the ground [4].…”