可変高さ倒立振子のバランス制御のための瞬時捕捉入力
Instantaneous Capture Input for Balancing the Variable Height Inverted Pendulum
脚式ロボットのバランス制御において、重心高さが変化する可変高さ倒立振子モデルに対し、瞬時捕捉点を拡張した「瞬時捕捉入力」を導入し、捕捉可能状態の解析的領域とオンライン最適フィードバックゲインを持つ制御器を提案した。
著者: Junwei Liu, Hua Chen, Patrick M. Wensing, Wei Zhang
分類: cs.RO
原文アブストラクト
Balancing is a fundamental need for legged robots due to their unstable floating-base nature. Balance control has been thoroughly studied for simple models such as the linear inverted pendulum thanks to the concept of the instantaneous capture point (ICP), yet the constant center of mass height assumption limits the application. This paper explores balancing of the variable-height inverted pendulum (VHIP) model by introducing the \emph{instantaneous capture input} (ICI), an extension of the ICP based on its key properties. Namely, the ICI can be computed as a function of the state, and when this function is used as the control policy, the ICI is rendered stationary and the system will eventually come to a stop. This characterization induces an analytical region of capturable states for the VHIP, which can be used to conceptually guide where to step. To further address state and control constraints during recovery, we present and theoretically analyze an explicit ICI-based controller with online optimal feedback gains. Simulations demonstrate the validity of our controller for capturability maintenance compared to an approach based on the divergent component of motion.
