CTBC: Contact-Triggered Blind Climbing for Wheeled Bipedal Robots with Instruction Learning and Reinforcement Learning

Rankun Li*,1,2, Hao Wang*,2, Qi Li*,2, Zhuo Han1,2, Yifei Chu2, Linqi Ye†,1, Wende Xie†,2, Wenlong Liao2
1 Shanghai University 2 COWAROBOT Co. Ltd.
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ICRA 2026
Submitted

*Indicates Equal Contribution
Indicates Corresponding Author

Project Video

Abstract

In recent years, wheeled bipedal robots have gained increasing attention due to their advantages in mobility, such as high-speed locomotion on flat terrain. However, their performance on complex environments (e.g., staircases) remains inferior to that of traditional legged robots. To overcome this limitation, we propose a general contact-triggered blind climbing (CTBC) framework for wheeled bipedal robots. Upon detecting wheel-obstacle contact, the robot triggers a leg-lifting motion to overcome the obstacle. By leveraging a strongly-guided feedforward trajectory, our method enables the robot to rapidly acquire agile leg-lifting skills, significantly enhancing its capability to traverse unstructured terrains. The approach has been experimentally validated and successfully deployed on LimX Dynamics' wheeled bipedal robot, Tron1. Real-world tests demonstrate that Tron1 can reliably climb obstacles well beyond its wheel radius using only proprioceptive feedback.

Framework

CTBC Framework Overview

Ablation Experiments in Sim

Hole-Escape

Stair-Climbing

Multi-Step Stairs

BibTeX

@misc{li2025ctbccontacttriggeredblindclimbing,
      title={CTBC: Contact-Triggered Blind Climbing for Wheeled Bipedal Robots with Instruction Learning and Reinforcement Learning}, 
      author={Rankun Li and Hao Wang and Qi Li and Zhuo Han and Yifei Chu and Linqi Ye and Wende Xie and Wenlong Liao},
      year={2025},
      eprint={2509.02986},
      archivePrefix={arXiv},
      primaryClass={cs.RO},
      url={https://arxiv.org/abs/2509.02986 }, 
}