DiG-Flow: Discrepancy-Guided Flow Matching for Robust VLA Models

Fuente: arXiv
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Auteurs principaux: Zhang, Wanpeng, Wang, Ye, Luo, Hao, Yuan, Haoqi, Feng, Yicheng, Zheng, Sipeng, Jin, Qin, Lu, Zongqing
Format: Preprint
Publié: 2025
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author Zhang, Wanpeng
Wang, Ye
Luo, Hao
Yuan, Haoqi
Feng, Yicheng
Zheng, Sipeng
Jin, Qin
Lu, Zongqing
author_facet Zhang, Wanpeng
Wang, Ye
Luo, Hao
Yuan, Haoqi
Feng, Yicheng
Zheng, Sipeng
Jin, Qin
Lu, Zongqing
contents Vision-Language-Action (VLA) models trained with flow matching have demonstrated impressive capabilities on robotic manipulation tasks. However, their performance often degrades under distribution shift and on complex multi-step tasks, suggesting that the learned representations may not robustly capture task-relevant semantics. We introduce DiG-Flow, a principled framework that enhances VLA robustness through geometric regularization. Our key insight is that the distributional discrepancy between observation and action embeddings provides a meaningful geometric signal: lower transport cost indicates compatible representations, while higher cost suggests potential misalignment. DiG-Flow computes a discrepancy measure between empirical distributions of observation and action embeddings, maps it to a modulation weight via a monotone function, and applies residual updates to the observation embeddings before flow matching. Crucially, this intervention operates at the representation level without modifying the flow matching path or target vector field. We provide theoretical guarantees showing that discrepancy-guided training provably decreases the training objective, and that guided inference refinement converges with contraction. Empirically, DiG-Flow integrates into existing VLA architectures with negligible overhead and consistently improves performance, with particularly pronounced gains on complex multi-step tasks and under limited training data.
format Preprint
id arxiv_https___arxiv_org_abs_2512_01715
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle DiG-Flow: Discrepancy-Guided Flow Matching for Robust VLA Models
Zhang, Wanpeng
Wang, Ye
Luo, Hao
Yuan, Haoqi
Feng, Yicheng
Zheng, Sipeng
Jin, Qin
Lu, Zongqing
Robotics
Vision-Language-Action (VLA) models trained with flow matching have demonstrated impressive capabilities on robotic manipulation tasks. However, their performance often degrades under distribution shift and on complex multi-step tasks, suggesting that the learned representations may not robustly capture task-relevant semantics. We introduce DiG-Flow, a principled framework that enhances VLA robustness through geometric regularization. Our key insight is that the distributional discrepancy between observation and action embeddings provides a meaningful geometric signal: lower transport cost indicates compatible representations, while higher cost suggests potential misalignment. DiG-Flow computes a discrepancy measure between empirical distributions of observation and action embeddings, maps it to a modulation weight via a monotone function, and applies residual updates to the observation embeddings before flow matching. Crucially, this intervention operates at the representation level without modifying the flow matching path or target vector field. We provide theoretical guarantees showing that discrepancy-guided training provably decreases the training objective, and that guided inference refinement converges with contraction. Empirically, DiG-Flow integrates into existing VLA architectures with negligible overhead and consistently improves performance, with particularly pronounced gains on complex multi-step tasks and under limited training data.
title DiG-Flow: Discrepancy-Guided Flow Matching for Robust VLA Models
topic Robotics
url https://arxiv.org/abs/2512.01715