让视觉语言动作模型在推理时自我检查,判断何时需要人类帮助。
INSIGHT: INference-time Sequence Introspection for Generating Help Triggers in Vision-Language-Action Models
- 用分词级不确定性信号训练模型预测是否需求助。
- 动态建模不确定性演化比静态评分更有效,准确率更高。
- 弱监督也可行,适合标注成本高的实际场景。
近期的视觉-语言-动作(VLA)模型展现出强大的泛化能力,但缺乏预判失败并请求人类协助的自省机制。本文提出 extbf{INSIGHT},一种基于分词级不确定性信号来预测 VLA 是否应请求帮助的学习框架。以 $π_0$-FAST 模型为基础,提取每个词元的熵、对数概率以及基于狄利克雷分布的偶然性与认知不确定性估计,并训练小型 Transformer 分类器将这些序列映射为求助触发信号。研究对比了强监督与弱监督两种训练方式,在分布内和分布外任务上的表现。结果表明:强标签能捕捉精细不确定性动态,实现可靠求助检测;而弱标签虽噪声较大,但在训练与评估一致时仍具竞争力,为密集标注不可行时提供可扩展路径。关键发现是,用 Transformer 建模分词级不确定性的时间演变,远优于静态序列评分。本研究首次系统评估了 VLA 中基于不确定性的自省机制,为在线主动学习与选择性人工干预下的实时错误缓解开辟新方向。
原文摘要 · Abstract (English)
Recent Vision-Language-Action (VLA) models show strong generalization capabilities, yet they lack introspective mechanisms for anticipating failures and requesting help from a human supervisor. We present \textbf{INSIGHT}, a learning framework for leveraging token-level uncertainty signals to predict when a VLA should request help. Using $π_0$-FAST as the underlying model, we extract per-token \emph{entropy}, \emph{log-probability}, and Dirichlet-based estimates of \emph{aleatoric and epistemic uncertainty}, and train compact transformer classifiers to map these sequences to help triggers. We explore supervision regimes for strong or weak supervision, and extensively compare them across in-distribution and out-of-distribution tasks. Our results show a trade-off: strong labels enable models to capture fine-grained uncertainty dynamics for reliable help detection, while weak labels, though noisier, still support competitive introspection when training and evaluation are aligned, offering a scalable path when dense annotation is impractical. Crucially, we find that modeling the temporal evolution of token-level uncertainty signals with transformers provides far greater predictive power than static sequence-level scores. This study provides the first systematic evaluation of uncertainty-based introspection in VLAs, opening future avenues for active learning and for real-time error mitigation through selective human intervention.
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