Adaptive Action Chunking at Inference-time for Vision-Language-Action Models

Fuente: arXiv
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Main Authors: Liang, Yuanchang, Wang, Xiaobo, Wang, Kai, Wang, Shuo, Peng, Xiaojiang, Chen, Haoyu, Chua, David Kim Huat, Vadakkepat, Prahlad
Format: Preprint
Published: 2026
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author Liang, Yuanchang
Wang, Xiaobo
Wang, Kai
Wang, Shuo
Peng, Xiaojiang
Chen, Haoyu
Chua, David Kim Huat
Vadakkepat, Prahlad
author_facet Liang, Yuanchang
Wang, Xiaobo
Wang, Kai
Wang, Shuo
Peng, Xiaojiang
Chen, Haoyu
Chua, David Kim Huat
Vadakkepat, Prahlad
contents In Vision-Language-Action (VLA) models, action chunking (i.e., executing a sequence of actions without intermediate replanning) is a key technique to improve robotic manipulation abilities. However, a large chunk size reduces the model's responsiveness to new information, while a small one increases the likelihood of mode-jumping, jerky behavior resulting from discontinuities between chunks. Therefore, selecting the optimal chunk size is an urgent demand to balance the model's reactivity and consistency. Unfortunately, a dominant trend in current VLA models is an empirical fixed chunk length at inference-time, hindering their superiority and scalability across diverse manipulation tasks. To address this issue, we propose a novel Adaptive Action Chunking (AAC) strategy, which exploits action entropy as the cue to adaptively determine the chunk size based on current predictions. Extensive experiments on a wide range of simulated and real-world robotic manipulation tasks have demonstrated that our approach substantially improves performance over the state-of-the-art alternatives. The videos and source code are publicly available at https://lance-lot.github.io/adaptive-chunking.github.io/.
format Preprint
id arxiv_https___arxiv_org_abs_2604_04161
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Adaptive Action Chunking at Inference-time for Vision-Language-Action Models
Liang, Yuanchang
Wang, Xiaobo
Wang, Kai
Wang, Shuo
Peng, Xiaojiang
Chen, Haoyu
Chua, David Kim Huat
Vadakkepat, Prahlad
Robotics
In Vision-Language-Action (VLA) models, action chunking (i.e., executing a sequence of actions without intermediate replanning) is a key technique to improve robotic manipulation abilities. However, a large chunk size reduces the model's responsiveness to new information, while a small one increases the likelihood of mode-jumping, jerky behavior resulting from discontinuities between chunks. Therefore, selecting the optimal chunk size is an urgent demand to balance the model's reactivity and consistency. Unfortunately, a dominant trend in current VLA models is an empirical fixed chunk length at inference-time, hindering their superiority and scalability across diverse manipulation tasks. To address this issue, we propose a novel Adaptive Action Chunking (AAC) strategy, which exploits action entropy as the cue to adaptively determine the chunk size based on current predictions. Extensive experiments on a wide range of simulated and real-world robotic manipulation tasks have demonstrated that our approach substantially improves performance over the state-of-the-art alternatives. The videos and source code are publicly available at https://lance-lot.github.io/adaptive-chunking.github.io/.
title Adaptive Action Chunking at Inference-time for Vision-Language-Action Models
topic Robotics
url https://arxiv.org/abs/2604.04161