The Anti-Misalignment Mechanism of Bionic Knee Joint of Lower Limb Exoskeleton Based on Spherical Cross Four-Bar
Jiaxun Wu, Ye He, Rufei Xia, Tianchi Chen, Zhi Liu, Hongyuan Zhang
Abstract
To minimize discomfort and injury risk in exoskeleton users, this paper addresses the misalignment between the device and the human knee joint. The knee's spatial motion complexity, characterized by multi-planar rotation axes as flexion angle changes, cannot be accurately replicated by existing single-axis or planar multi-center designs. A novel spherical cross four-bar linkage-based knee joint structure is proposed, leveraging its kinematic properties to mimic the knee's actual spatial motion. This design undergoes optimization calculations to determine the bionic knee's specific structure. A quantitative evaluation method using pneumatic sensor pads measures internal pressure distribution, comparing human-machine misalignment across different joint mechanisms. Experimental results demonstrate that the bionic knee significantly reduces unintended interaction forces, with maximum pressure values only one-third those of single-axis knee joints. This innovation addresses critical limitations in existing exoskeleton knee designs, enhancing comfort and safety during movement.
BibTeX
@inproceedings{iros2025_theantimisalignm,
title = {The Anti-Misalignment Mechanism of Bionic Knee Joint of Lower Limb Exoskeleton Based on Spherical Cross Four-Bar},
author = {Jiaxun Wu and Ye He and Rufei Xia and Tianchi Chen and Zhi Liu and Hongyuan Zhang},
booktitle = {IROS 2025},
year = {2025}
}