RoVer: Robot Reward Model as Test-Time Verifier for Vision-Language-Action Model

Fuente: arXiv
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Main Authors: Dai, Mingtong, Liu, Lingbo, Bai, Yongjie, Liu, Yang, Wang, Zhouxia, SU, Rui, Chen, Chunjie, Lin, Liang, Wu, Xinyu
Format: Preprint
Published: 2025
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_version_ 1866917010721472512
author Dai, Mingtong
Liu, Lingbo
Bai, Yongjie
Liu, Yang
Wang, Zhouxia
SU, Rui
Chen, Chunjie
Lin, Liang
Wu, Xinyu
author_facet Dai, Mingtong
Liu, Lingbo
Bai, Yongjie
Liu, Yang
Wang, Zhouxia
SU, Rui
Chen, Chunjie
Lin, Liang
Wu, Xinyu
contents Vision-Language-Action (VLA) models have become a prominent paradigm for embodied intelligence, yet further performance improvements typically rely on scaling up training data and model size -- an approach that is prohibitively expensive for robotics and fundamentally limited by data collection costs. We address this limitation with $\mathbf{RoVer}$, an embodied test-time scaling framework that uses a $\mathbf{Ro}$bot Process Reward Model (PRM) as a Test-Time $\mathbf{Ver}$ifier to enhance the capabilities of existing VLA models without modifying their architectures or weights. Specifically, RoVer (i) assigns scalar-based process rewards to evaluate the reliability of candidate actions, and (ii) predicts an action-space direction for candidate expansion/refinement. During inference, RoVer generates multiple candidate actions concurrently from the base policy, expands them along PRM-predicted directions, and then scores all candidates with PRM to select the optimal action for execution. Notably, by caching shared perception features, it can amortize perception cost and evaluate more candidates under the same test-time computational budget. Essentially, our approach effectively transforms available computing resources into better action decision-making, realizing the benefits of test-time scaling without extra training overhead. Our contributions are threefold: (1) a general, plug-and-play test-time scaling framework for VLAs; (2) a PRM that jointly provides scalar process rewards and an action-space direction to guide exploration; and (3) an efficient direction-guided sampling strategy that leverages a shared perception cache to enable scalable candidate generation and selection during inference.
format Preprint
id arxiv_https___arxiv_org_abs_2510_10975
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle RoVer: Robot Reward Model as Test-Time Verifier for Vision-Language-Action Model
Dai, Mingtong
Liu, Lingbo
Bai, Yongjie
Liu, Yang
Wang, Zhouxia
SU, Rui
Chen, Chunjie
Lin, Liang
Wu, Xinyu
Robotics
Vision-Language-Action (VLA) models have become a prominent paradigm for embodied intelligence, yet further performance improvements typically rely on scaling up training data and model size -- an approach that is prohibitively expensive for robotics and fundamentally limited by data collection costs. We address this limitation with $\mathbf{RoVer}$, an embodied test-time scaling framework that uses a $\mathbf{Ro}$bot Process Reward Model (PRM) as a Test-Time $\mathbf{Ver}$ifier to enhance the capabilities of existing VLA models without modifying their architectures or weights. Specifically, RoVer (i) assigns scalar-based process rewards to evaluate the reliability of candidate actions, and (ii) predicts an action-space direction for candidate expansion/refinement. During inference, RoVer generates multiple candidate actions concurrently from the base policy, expands them along PRM-predicted directions, and then scores all candidates with PRM to select the optimal action for execution. Notably, by caching shared perception features, it can amortize perception cost and evaluate more candidates under the same test-time computational budget. Essentially, our approach effectively transforms available computing resources into better action decision-making, realizing the benefits of test-time scaling without extra training overhead. Our contributions are threefold: (1) a general, plug-and-play test-time scaling framework for VLAs; (2) a PRM that jointly provides scalar process rewards and an action-space direction to guide exploration; and (3) an efficient direction-guided sampling strategy that leverages a shared perception cache to enable scalable candidate generation and selection during inference.
title RoVer: Robot Reward Model as Test-Time Verifier for Vision-Language-Action Model
topic Robotics
url https://arxiv.org/abs/2510.10975