World-VLA-Loop: Closed-Loop Learning of Video World Model and VLA Policy

Fuente: arXiv
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Autores principales: Liu, Xiaokang, Bai, Zechen, Ci, Hai, Ma, Kevin Yuchen, Shou, Mike Zheng
Formato: Preprint
Publicado: 2026
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author Liu, Xiaokang
Bai, Zechen
Ci, Hai
Ma, Kevin Yuchen
Shou, Mike Zheng
author_facet Liu, Xiaokang
Bai, Zechen
Ci, Hai
Ma, Kevin Yuchen
Shou, Mike Zheng
contents Reinforcement learning (RL) can refine Vision-Language-Action (VLA) policies beyond behavior cloning, but real-world RL remains expensive due to extensive rollouts, resets, supervision, and safety risks. Action-conditioned video world models offer an option to train in virtual environments, yet they exhibit imprecise action following, particularly on subtle near-success failures. Besides, they lack native reward signals for RL. Computing rewards based on inaccurate visual predictions remain unreliable. We introduce World-VLA-Loop, structured around two foundational designs and a higher-level co-evolving paradigm. We first curate SANS, dedicatedly mixing successful and near-success trajectories to improve action-outcome alignment. Then, we train a state-aware video world model that jointly predicts future frames and binary rewards from diffusion latents. It couples reward estimation to the generator rather than a separate module, and in turn, benefits visual prediction. Since VLA behavior shifts during RL, a fixed simulator can misalign with the updated policy, World-VLA-Loop therefore closes the loop by using the refined world model for iterative VLA post-training while feeding rollouts from each improved policy back to augment and fine-tune the world model. Across simulation and real-robot experiments, World-VLA-Loop substantially improves VLA performance while reducing reliance on costly physical interaction.
format Preprint
id arxiv_https___arxiv_org_abs_2602_06508
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle World-VLA-Loop: Closed-Loop Learning of Video World Model and VLA Policy
Liu, Xiaokang
Bai, Zechen
Ci, Hai
Ma, Kevin Yuchen
Shou, Mike Zheng
Robotics
I.2.9
Reinforcement learning (RL) can refine Vision-Language-Action (VLA) policies beyond behavior cloning, but real-world RL remains expensive due to extensive rollouts, resets, supervision, and safety risks. Action-conditioned video world models offer an option to train in virtual environments, yet they exhibit imprecise action following, particularly on subtle near-success failures. Besides, they lack native reward signals for RL. Computing rewards based on inaccurate visual predictions remain unreliable. We introduce World-VLA-Loop, structured around two foundational designs and a higher-level co-evolving paradigm. We first curate SANS, dedicatedly mixing successful and near-success trajectories to improve action-outcome alignment. Then, we train a state-aware video world model that jointly predicts future frames and binary rewards from diffusion latents. It couples reward estimation to the generator rather than a separate module, and in turn, benefits visual prediction. Since VLA behavior shifts during RL, a fixed simulator can misalign with the updated policy, World-VLA-Loop therefore closes the loop by using the refined world model for iterative VLA post-training while feeding rollouts from each improved policy back to augment and fine-tune the world model. Across simulation and real-robot experiments, World-VLA-Loop substantially improves VLA performance while reducing reliance on costly physical interaction.
title World-VLA-Loop: Closed-Loop Learning of Video World Model and VLA Policy
topic Robotics
I.2.9
url https://arxiv.org/abs/2602.06508