A Discrete Variable Stiffness Actuator for Robotic Hand
Jiahang Zhu, Ke Shi, Tongshu Chen, Maozeng Zhang, Aiguo Song
Abstract
Variable stiffness actuators can dynamically adjust output stiffness to accommodate varying task demands, making them well suited for grasping applications. Nevertheless, conventional variable stiffness actuators often suffer from bulky structures, slow response, and complex control, which hinders their integration into robotic hands. To overcome these limitations, we designed a discrete variable stiffness actuator (DVSA) based on electrostatic clutches (ESCs). The DVSA comprises multiple parallel units, each with a linear spring in series with an ESC. By selectively activating ESCs, the DVSA couples different springs to achieve discrete stiffness modulation. This design provides a compact structure and fast response. Furthermore, a cable-driven robotic hand was developed with the DVSA integrated into the palm. A grasping control strategy was also designed to estimate object stiffness in real time and adjust the stiffness of the DVSA accordingly. The performance of the DVSA and the robotic hand was evaluated experimentally. The results indicate that the robotic hand demonstrates excellent stiffness modulation performance under both static and dynamic grasping conditions.
BibTeX
@inproceedings{ral2026_adiscretevariabl,
title = {A Discrete Variable Stiffness Actuator for Robotic Hand},
author = {Jiahang Zhu and Ke Shi and Tongshu Chen and Maozeng Zhang and Aiguo Song},
booktitle = {RA-L 2026},
year = {2026}
}