arXiv AI

Do VLAs Know They Will Fail? Interpretable Success and Failure Patterns in Physical AI Systems

The paper investigates Vision‑Language‑Action (VLA) models used as robot policies, showing that sparse autoencoder (SAE) representations of OpenVLA activations can predict task failure before an unrecoverable state is reached. It identifies specific SAE features whose strong activations correlate with stages of success or failure, and maps these to recurring behavioral patterns by locating temporal intervals of significant activation change. A VLM‑based interpretation pipeline is then developed to generate behavioral descriptions of these patterns, with validation on held‑out intervals.

arXiv AI
Sep 28

Hide-and-Seek in Trajectories: Discovering Failure Signals for VLA Runtime Monitoring

The paper introduces Hide-and-Seek, a framework for detecting failures in Vision‑Language‑Action (VLA) models during robot execution. It treats failure detection as a coarsely supervised learning problem, using inter‑trajectory and intra‑trajectory contrastive objectives to localize failure‑indicative actions without step‑level annotations. Experiments on LIBERO, VLABench, and a real‑world robotic platform show that Hide‑and‑Seek achieves state‑of‑the‑art multi‑task failure detection performance across several VLA policies.

By Seongheon Park, Wendi Li, Changdae Oh, Samuel Yeh, Zsolt Kira, Michael Hagenow, Sharon Li
arXiv AI
1d ago

Failure Prediction and Classification in Vision-Language-Action Models Via Calibrated Latent Probing

The paper introduces VLA‑Tug, a lightweight probe that monitors latent layers of Vision‑Language‑Action models to detect failures early and predict failure modes. By supervising on pre‑failure segments, it improves early detection by up to 30% at matched false‑positive rates and maintains valid missed‑detection and false‑alarm bounds in 86% of runs under unseen task shifts, outperforming existing baselines. The method also raises top‑3 accuracy on unseen tasks by up to 44% and supports real‑time, edge‑efficient monitoring for safer deployment.

By Michal P. Podolinsky, Yunhao Yang, Daniel Little, Hong Lu, Rohan Siva, Olin Goudey, Neel P. Bhatt, Matthias Scheutz, Ufuk Topcu
arXiv Machine Learning
Oct 12

VLA-FAIL: Efficient Task Failure Detection for Finetuned Vision-Language-Action Models

VLA-FAIL introduces a lightweight framework for detecting failures in vision-language-action models used in robotic manipulation. It combines two novel detectors: the first-layer Mahalanobis distance (LLMD) identifies out-of-distribution states by comparing token-wise deviations in last-layer features to training data, while the second, action chunk consistency (ACC), detects failures by spotting inconsistencies between consecutive action chunks in receding-horizon control. The authors also propose a threshold‑independent metric, “AUCPDT,” to evaluate detection accuracy and latency, and show through real‑world and simulation experiments that LLMD and ACC together provide reliable and early failure detection, outperforming more expensive baseline methods.

By Florian Seligmann, Emiliyan Gospodinov, Enes Ulas Dincer, Gerhard Neumann
arXiv AI
Oct 5

Detect and Suppress: A Mechanistic Defense against Adversarial Patches in VLA Models

The paper presents a mechanistic defense for Vision‑Language‑Action (VLA) models against adversarial patches. By using a sparse autoencoder, the authors identify a feature whose activation correlates strongly with the presence of an adversarial patch and suppress this feature only when a linear probe detects an attack. This conditional intervention improves robustness on the LIBERO‑10 benchmark while avoiding the performance degradation that occurs with continuous suppression.

By Yukiya Horiba, Koshiro Aoki, Shunsuke Yasuki, Bum Jun Kim, Taiki Miyanishi
arXiv Computer Vision
Aug 28

TrapVLA: Trapping Vision-Language-Action Models in Configured Failure Modes

The paper introduces Configured Failure Trapping, a new backdoor attack targeting Vision‑Language‑Action (VLA) models that activates through subtle textual triggers and forces the robot to fail in a specific, controlled manner. It presents a data engine for generating high‑quality target trajectories, an automated evaluation suite, and two benchmarks—Trap‑LIBERO and Trap‑RoboTwin—covering four failure modes. The authors propose TrapVLA, a method that learns trigger‑induced action residuals to steer policies toward the desired failure behavior, demonstrating effectiveness in both simulation and real‑world robotic experiments while maintaining performance on clean data.

By Jun-Hui Liu, Kun-Yu Lin, Yi-Lin Wei, Xu-Han Chen, Yinghao Li, Zhuohao Li, Yuan-Ming Li, Qing Zhang, Xiaoyi Fan, Dongmei Jiang, Yan Li, Wei-Shi Zheng
arXiv Computer Vision
Sep 7

FailureSpot: Label-Efficient Timestamp-Level Failure Detection for Vision-Language-Action Models

The paper introduces FailureSpot, a label‑efficient method for detecting failures at the timestamp level in vision‑language‑action (VLA) policies. It first generates weak supervision from unlabeled VLA action chunks by identifying abnormal patterns, then employs active learning to annotate only the most uncertain trajectories. Experiments on multiple VLA policies demonstrate improved performance for both timestamp‑level and trajectory‑level failure detection.

By Jie Ma, Zongxi Liu, Yi Zhu
arXiv AI
Sep 21

VLA-Scope: Shift-Aware Failure Prediction for Vision-Language-Action Models

VLA-Scope is a two‑stage framework designed to predict failures in vision‑language‑action models under distribution shifts. The first stage detects out‑of‑distribution inputs and classifies their shift categories using pooled image and language representations. For OOD inputs, the second stage updates failure risk during execution by combining shift category, action‑prefix features, and execution progress, achieving a ROC‑AUC of 0.8497 after 60 actions and outperforming baseline methods.

By Kaiwen Zhu, Dongfang Liu, Liangkai Liu
arXiv AI
Sep 4

FailBench: How Reliable are VLMs at Judging Robot Task Success?

FailBench is a new benchmark for robot failure detection, containing 2,197 manipulation attempts from 14 public sources, with 75% of failures occurring naturally. The study evaluates 13 vision‑language model (VLM) detectors, finding the best model achieves only 0.77 mean balanced accuracy, and that fine‑tuned failure detectors often underperform general‑purpose VLMs. Performance varies with visual evidence, excelling when object motion is observable but dropping to near chance on contact‑intensive assembly tasks, and input‑level cropping of outcome‑relevant regions improves the top detector by 2.4 percentage points.

By Zaruhi Navasardyan, Tatul Danielyan, Hrant Davtyan