Safe Control of Quadruped in Varying Dynamics
via Safety Index Adaptation

Kai S. Yun1        Rui Chen1        Chase Dunaway2        John M. Dolan1        Changliu Liu1
1Carnegie Mellon University; 2New Mexico Institute of Mining and Technology ICRA 2025
arXiv Video

Abstract

Varying dynamics pose a fundamental difficulty when deploying safe control laws in the real world. Safety Index Synthesis (SIS) deeply relies on the system dynamics and once the dynamics change, the previously synthesized safety index becomes invalid. In this work, we show the real-time efficacy of Safety Index Adaptation (SIA) in varying dynamics. SIA enables real-time adaptation to the changing dynamics so that the adapted safe control law can still guarantee 1) forward invariance within a safe region and 2) finite time convergence to that safe region. This work employs SIA on a package-carrying quadruped robot, where the payload weight changes in real-time. SIA updates the safety index when the dynamics change, e.g., a change in payload weight, so that the quadruped can avoid obstacles while achieving its performance objectives. Numerical study provides theoretical guarantees for SIA and a series of hardware experiments demonstrate the effectiveness of SIA in real-world deployment in avoiding obstacles under varying dynamics.

Safety Index Adaptation Experiment Pipeline


Overview

SIA Experiments (Safety Index Adapted for Each Package Weight)

Baseline Experiments (Non-adapted Safety Index for Empty Payload)

Related Work

This work is part of our research on provably safe control. Please explore our other contributions below.
RMA Image

SPARK: A Modular Benchmark for Humanoid Robot Safety

Yifan Sun, Rui Chen, Kai S. Yun, Yikuan Fang, Sebin Jung, Feihan Li, Bowei Li, Weiye Zhao, Changliu Liu
Submitted to RSS 2025

arXiv Video Project Page

RMA Image

Real-time Safety Index Adaptation for Parameter-varying Systems via Determinant Gradient Ascend

Rui Chen, Weiye Zhao, Ruixuan Liu, Weiyang Zhang, Changliu Liu
Accepted to ACC 2024

arXiv

BibTeX

          
            @inproceedings{yun2025siadog,
              title={Safe Control of Quadruped in Varying Dynamics via Safety Index Adaptation},
              author={Yun, Kai S. and Chen, Rui and Dunaway, Chase and Dolan, John M. and Liu, Changliu},
              booktitle={IEEE International Conference on Robotics and Automation},
              year={2025},
              organization={IEEE},
              url={https://www.arxiv.org/abs/2409.09882},
              video={https://www.youtube.com/watch?v=g64ZzJxaHpk},
            }