関節トルク計測を活用した重心状態推定
On the Use of Torque Measurement in Centroidal State Estimation
脚式ロボットの関節トルク測定を接触制約の零空間に射影し、拡張カルマンフィルタで重心状態を推定する手法を提案し、四足歩行ロボット実験で直接計算より精度が向上することを示した。
著者: Shahram Khorshidi, Ahmad Gazar, Nicholas Rotella, Maximilien Naveau, Ludovic Righetti, Maren Bennewitz, Majid Khadiv
分類: cs.RO
原文アブストラクト
State of the art legged robots are either capable of measuring torque at the output of their drive systems, or have transparent drive systems which enable the computation of joint torques from motor currents. In either case, this sensor modality is seldom used in state estimation. In this paper, we propose to use joint torque measurements to estimate the centroidal states of legged robots. To do so, we project the whole-body dynamics of a legged robot into the nullspace of the contact constraints, allowing expression of the dynamics independent of the contact forces. Using the constrained dynamics and the centroidal momentum matrix, we are able to directly relate joint torques and centroidal states dynamics. Using the resulting model as the process model of an Extended Kalman Filter (EKF), we fuse the torque measurement in the centroidal state estimation problem. Through real-world experiments on a quadruped robot with different gaits, we demonstrate that the estimated centroidal states from our torque-based EKF drastically improve the recovery of these quantities compared to direct computation.
