Manipulation of Center of Pressure for Bipedal Locomotion by Passive Twisting of Viscoelastic Trunk Joint and Asymmetrical Arm Swinging
Takashi Takuma, Ibuki Hashimoto, Ryo Andachi, Yasuhiro Sugimoto, Shinya Aoi
Abstract
To implement successful bipedal locomotion in a robot, its center of pressure (CoP) is placed on a supporting area. To achieve locomotion, many studies have focused on the lower body. Given that the human upper body has a large mass and its behavior influences locomotion even in the case of the robot, this study investigates the effect of the upper body, which contains moving arms and a twisting trunk, on CoP. The dynamics is analyzed using a simple model that has a passive viscoelastic trunk joint around the vertical axis and arms that oscillates back and forth. From the derivations of CoP and trunk joint trajectory, three important findings are made: (i) the CoP oscillates along the lateral direction only when the arm swings in an anterior-posterior asymmetric manner, (ii) the trajectories of CoP and trunk joint are in anti-phase, (iii) the phase of CoP along the lateral direction is influenced by the swinging cycle and viscoelasticity of the trunk joint, the mechanical elements of the upper body. An experiment using a robot verified the first and second findings, and simulation verified the last finding. The last finding will contribute to making a feedback controller that converges to the desired phase, which is an important factor for successful bipedal locomotion.
BibTeX
@inproceedings{iros2023_manipulationofce,
title = {Manipulation of Center of Pressure for Bipedal Locomotion by Passive Twisting of Viscoelastic Trunk Joint and Asymmetrical Arm Swinging},
author = {Takashi Takuma and Ibuki Hashimoto and Ryo Andachi and Yasuhiro Sugimoto and Shinya Aoi},
booktitle = {IROS 2023},
year = {2023}
}