揺れる剛体面上を歩行する劣駆動ヒューマノイドのための時変足配置制御
Time-Varying Foot-Placement Control for Underactuated Humanoid Walking on Swaying Rigid Surfaces
周期的に揺れる剛体面（電車・船・航空機など）上での劣駆動ヒューマノイド歩行を安定化するため、角運動量ベースの線形倒立振子モデルを揺れる地面に拡張し、時変足配置制御則と階層制御フレームワークを開発した。Digitロボットのシミュレーションと実機実験で有効性を示した。
著者: Yuan Gao, Victor Paredes, Yukai Gong, Zijian He, Ayonga Hereid, Yan Gu
分類: cs.RO, cs.SY, eess.SY
原文アブストラクト
Locomotion on dynamic rigid surface (i.e., rigid surface accelerating in an inertial frame) presents complex challenges for controller design, which are essential for deploying humanoid robots in dynamic real-world environments such as moving trains, ships, and airplanes. This paper introduces a real-time, provably stabilizing control approach for underactuated humanoid walking on periodically swaying rigid surface. The first key contribution is the analytical extension of the classical angular momentum-based linear inverted pendulum model from static to swaying grounds. This extension results in a time-varying, nonhomogeneous robot model, which is fundamentally different from the existing pendulum models. We synthesize a discrete footstep control law for the model and derive a new set of sufficient stability conditions that verify the controller's stabilizing effect. Another key contribution is the development of a hierarchical control framework that incorporates the proposed footstep control law as its higher-layer planner to ensure the stability of underactuated walking. The closed-loop stability of the complete hybrid, full-order robot dynamics under this control framework is provably analyzed based on nonlinear control theory. Finally, experiments conducted on a Digit humanoid robot, both in simulations and with hardware, demonstrate the framework's effectiveness in addressing underactuated bipedal locomotion on swaying ground, even in the presence of uncertain surface motions and unknown external pushes.
