CMoE: Contrastive Mixture of Experts for Motion Control and Terrain Adaptation of Humanoid Robots

Fuente: arXiv
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Main Authors: Ma, Shihao, Chen, Hongjin, Xu, Zijun, Zhao, Yi, Wu, Ke, Yang, Ruichen, Zou, Leyao, Gan, Zhongxue, Ding, Wenchao
Format: Preprint
Published: 2026
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author Ma, Shihao
Chen, Hongjin
Xu, Zijun
Zhao, Yi
Wu, Ke
Yang, Ruichen
Zou, Leyao
Gan, Zhongxue
Ding, Wenchao
author_facet Ma, Shihao
Chen, Hongjin
Xu, Zijun
Zhao, Yi
Wu, Ke
Yang, Ruichen
Zou, Leyao
Gan, Zhongxue
Ding, Wenchao
contents For effective deployment in real-world environments, humanoid robots must autonomously navigate a diverse range of complex terrains with abrupt transitions. While the Vanilla mixture of experts (MoE) framework is theoretically capable of modeling diverse terrain features, in practice, the gating network exhibits nearly uniform expert activations across different terrains, weakening the expert specialization and limiting the model's expressive power. To address this limitation, we introduce CMoE, a novel single-stage reinforcement learning framework that integrates contrastive learning to refine expert activation distributions. By imposing contrastive constraints, CMoE maximizes the consistency of expert activations within the same terrain while minimizing their similarity across different terrains, thereby encouraging experts to specialize in distinct terrain types. We validated our approach on the Unitree G1 humanoid robot through a series of challenging experiments. Results demonstrate that CMoE enables the robot to traverse continuous steps up to 20 cm high and gaps up to 80 cm wide, while achieving robust and natural gait across diverse mixed terrains, surpassing the limits of existing methods. To support further research and foster community development, we release our code publicly.
format Preprint
id arxiv_https___arxiv_org_abs_2603_03067
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CMoE: Contrastive Mixture of Experts for Motion Control and Terrain Adaptation of Humanoid Robots
Ma, Shihao
Chen, Hongjin
Xu, Zijun
Zhao, Yi
Wu, Ke
Yang, Ruichen
Zou, Leyao
Gan, Zhongxue
Ding, Wenchao
Robotics
For effective deployment in real-world environments, humanoid robots must autonomously navigate a diverse range of complex terrains with abrupt transitions. While the Vanilla mixture of experts (MoE) framework is theoretically capable of modeling diverse terrain features, in practice, the gating network exhibits nearly uniform expert activations across different terrains, weakening the expert specialization and limiting the model's expressive power. To address this limitation, we introduce CMoE, a novel single-stage reinforcement learning framework that integrates contrastive learning to refine expert activation distributions. By imposing contrastive constraints, CMoE maximizes the consistency of expert activations within the same terrain while minimizing their similarity across different terrains, thereby encouraging experts to specialize in distinct terrain types. We validated our approach on the Unitree G1 humanoid robot through a series of challenging experiments. Results demonstrate that CMoE enables the robot to traverse continuous steps up to 20 cm high and gaps up to 80 cm wide, while achieving robust and natural gait across diverse mixed terrains, surpassing the limits of existing methods. To support further research and foster community development, we release our code publicly.
title CMoE: Contrastive Mixture of Experts for Motion Control and Terrain Adaptation of Humanoid Robots
topic Robotics
url https://arxiv.org/abs/2603.03067