A Bio-inspired Stiffness-programmable Robotic Flexible Joint Based on Electro-adhesive Clutches
Yongxian Ma, Chuang Wu, Qingbiao Li, Chongjing Cao, Xiaozheng Li
Abstract
Robots with active variable stiffness (VS) capabilities can potentially achieve safer interactions with humans and better adaptabilities to uncertainties in complex environments. Currently, the conventional jamming or phase-change-based VS mechanisms simultaneously act on the stiffnesses of the robotic joint in all axes, making it difficult to achieve decoupled stiffness programming in different directions/axes. To overcome this challenge, a bio-inspired stiffness-programmable robotic flexible joint (SPRFJ) based on the electro-adhesive (EA) clutches is proposed. By programming the ON/OFF states of the EA clutches on different surfaces around the SPRFJ, customization of stiffness profiles in different directions/axes can be realized, and therefore, the load-bearing capacity and flexibility of the robotic arm can be adjusted. A SPRFJ prototype consisting of four EA clutch units is developed, and through extensive experiments, we demonstrate that it can achieve a stiffness change of 21 times and can withstand resisting forces up to 13.41 N at 1 kV. The reliable multi-directional stiffness programmability of the SPRFJ is shown via extensive tests. Demonstrations on stable position locking at different angles and free movements while carrying payloads are conducted to showcase its application in soft robotics. This SPRFJ developed in this work processes the potential in industrial robots, search-and-rescue missions, and space explorations.
BibTeX
@inproceedings{iros2025_abioinspiredstif,
title = {A Bio-inspired Stiffness-programmable Robotic Flexible Joint Based on Electro-adhesive Clutches},
author = {Yongxian Ma and Chuang Wu and Qingbiao Li and Chongjing Cao and Xiaozheng Li},
booktitle = {IROS 2025},
year = {2025}
}