Guarding Force: Safety-Critical Compliant Control for Robot-Environment Interaction
Xinming Wang, Jun Yang, Jianliang Mao, Shihua Li, Yunda Yan
Abstract
In this letter, we propose a safety-critical compliant control strategy designed to strictly enforce interaction force constraints during the physical interaction of robots with environments. The interaction force constraint is interpreted as a new force-constrained control barrier function (FC-CBF) by exploiting the generalized contact model with the prior information of the environment, e.g., the prior stiffness, for robot kinematics. The difference between the real environment and the generalized contact model is approximated by constructing an uncertainty observer, and its estimation error is quantified on the basis of Lyapunov theory. By interpreting strict interaction safety specifications as a dynamic constraint and restricting the desired joint angular velocities in kinematics, the proposed approach modifies nominal compliant controllers using quadratic programming, ensuring adherence to interaction force constraints in partially uncertain environments. The strict force constraint and the stability of the closed-loop system are rigorously analyzed. Experimental tests using a UR3e industrial robot with different environments verify the effectiveness of the proposed method in achieving the force constraints.
BibTeX
@inproceedings{ral2026_guardingforcesaf,
title = {Guarding Force: Safety-Critical Compliant Control for Robot-Environment Interaction},
author = {Xinming Wang and Jun Yang and Jianliang Mao and Shihua Li and Yunda Yan},
booktitle = {RA-L 2026},
year = {2026}
}