Harmonic Principle-Based Adjustable Constant-Force Mechanism for Stable Human-Robot Interaction in Massage Robotics
Lixing Jin, Xuanquan Wang, Xinchun Wang, Xingguang Duan, Li Zhang
Abstract
Stable and precise force contact is critical in human-robot interaction, typically requiring precise sensors and advanced algorithms. This paper presents a novel adjustable constant-force mechanism (CFM) serving as a force generator for massage robotic systems, aiming to reduce hardware costs and system development complexity. The passive CFM, comprising gears and springs, is further integrated with an active motor to enable online adjustment and continuous operation. As the primary innovation, the harmonic principle is employed for force regulation in the CFM, replacing traditional methods such as altering the number or assembly position of springs, which provides a more convenient integration with automated systems. This involves the superposition of two elastic systems with identical configurations, where only the phase angle is extracted as the sole control variable for force modulation. A prototype was constructed to experimentally validate its performance. Results demonstrate that the proposed solution achieves a maximum constant output force of 18.34 N over a 55 mm range, and it can be adjusted online to the appropriate level as required by the task.
BibTeX
@inproceedings{ral2026_harmonicprincipl,
title = {Harmonic Principle-Based Adjustable Constant-Force Mechanism for Stable Human-Robot Interaction in Massage Robotics},
author = {Lixing Jin and Xuanquan Wang and Xinchun Wang and Xingguang Duan and Li Zhang},
booktitle = {RA-L 2026},
year = {2026}
}