Drift is a Sampling Error: SNR-Aware Power Distributions for Long-Horizon Robotic Planning
On the map: Vision-language-action models → Reinforcement learning and post-training
Abstract (arXiv)
Despite rapid progress in Vision-Language-Action (VLA) models for robotic control, instruction drift remains a persistent failure mode in long-horizon tasks. This paper reconceptualizes this phenomenon, positing that instruction drift is fundamentally a systematic sampling error: local greedy sampling is prone to collapsing into "Negative Pivotal Windows"--irreversible local optima with high local probability that sever global success pathways. To address this, we propose Context-Aware Power Sampling (CAPS), a training-free inference-time computation framework. CAPS leverages power distributions to sharpen global trajectory probabilities, enabling lookahead search over the model's conditional generative trajectory distribution. Furthermore, we introduce a metacognitive control mechanism based on Signal-to-Noise Ratio (SNR). This mechanism triggers adaptive MCMC search solely when drift risk is detected, enabling a dynamic transition from "intuitive fast thinking" to "rational slow search." Experiments on RoboTwin, Simpler-WindowX, and Libero-long benchmarks show that CAPS achieves substantial improvements over strong baselines, including OpenVLA and TACO, without parameter updates. These results support the effectiveness of adaptive inference-time computation for improving long-horizon robustness in embodied control.
Key facts. Cited by 3 papers in the map (data through 14 Oct 2026). Placed in Reinforcement learning and post-training, one of 13 directions in Vision-language-action models. Builds on 32 of its 40 references that are in the map. First posted on arXiv 10 May 2026.
Builds on
32 of 40 references.
Closest ancestors · 1
Same direction, newest first
Other references · 31
- 2022Chain-of-Thought Prompting Elicits Reasoning in Large Language Modelscited by 12,459
- 2022ReAct: Synergizing Reasoning and Acting in Language Modelscited by 8,695
- 2023Let's Verify Step by Stepcited by 3,789
- 2023Tree of Thoughts: Deliberate Problem Solving with Large Language Modelscited by 3,211
- 2023RT-2: Vision-Language-Action Models Transfer Web Knowledge to Robotic Controlcited by 3,080
- 2024OpenVLA: An Open-Source Vision-Language-Action Modelcited by 2,887
- 2024π0: A Vision-Language-Action Flow Model for General Robot Controlcited by 2,407
- 2022Do As I Can, Not As I Say: Grounding Language in Robotic Affordancescited by 2,348
- 2025π0.5: a Vision-Language-Action Model with Open-World Generalizationcited by 1,761
- 2023LIBERO: Benchmarking Knowledge Transfer for Lifelong Robot Learningcited by 1,410
- 2023Open X-Embodiment: Robotic Learning Datasets and RT-X Modelscited by 862
- 2024RDT-1B: a Diffusion Foundation Model for Bimanual Manipulationcited by 691
19 more
- 2024BLINK: Multimodal Large Language Models Can See but Not Perceivecited by 550
- 2025SpatialVLA: Exploring Spatial Representations for Visual-Language-Action Modelcited by 519
- 2024Evaluating Real-World Robot Manipulation Policies in Simulationcited by 495
- 2025CoT-VLA: Visual Chain-of-Thought Reasoning for Vision-Language-Action Modelscited by 451
- 2024Inference Scaling Laws: An Empirical Analysis of Compute-Optimal Inference for Problem-Solving with Language Modelscited by 290
- 2024VLABench: A Large-Scale Benchmark for Language-Conditioned Robotics Manipulation with Long-Horizon Reasoning Taskscited by 175
- 2025Uncertainty Quantification and Confidence Calibration in Large Language Models: A Surveycited by 95
- 2025Reasoning with Sampling: Your Base Model is Smarter Than You Thinkcited by 89
- 2024The Ingredients for Robotic Diffusion Transformerscited by 73
- 2024M2Diffuser: Diffusion-based Trajectory Optimization for Mobile Manipulation in 3D Scenescited by 27
- 2025The Pitfalls of Imitation Learning when Actions are Continuouscited by 26
- 2024Long-horizon Locomotion and Manipulation on a Quadrupedal Robot with Large Language Modelscited by 21
- 2025Steering Vision-Language-Action Models as Anti-Exploration: A Test-Time Scaling Approachcited by 21
- 2025A Survey of Slow Thinking-based Reasoning LLMs using Reinforced Learning and Inference-time Scaling Lawcited by 19
- 2024QUEST: Quality-Aware Metropolis-Hastings Sampling for Machine Translationcited by 16
- 2025REALM: A Real-to-Sim Validated Benchmark for Generalization in Robotic Manipulationcited by 15
- 2024Enhancing Multi-Robot Semantic Navigation Through Multimodal Chain-of-Thought Score Collaborationcited by 14
- 2025VLDrive: Vision-Augmented Lightweight MLLMs for Efficient Language-grounded Autonomous Drivingcited by 6
- 2025PRISM: Pointcloud Reintegrated Inference via Segmentation and Cross-attention for Manipulationcited by 1
Built on by
Citing papers per year: 2026: 3.
3 papers.
Similar, not cited
Close in wording, no citation either way
- 2026VLS: Steering Pretrained Robot Policies via Vision-Language Models
- 2025Exploration and Adaptation in Non-Stationary Tasks with Diffusion Policies
- 2025SITCOM: Scaling Inference-Time COMpute for VLAs
- 2025Verifier-free Test-Time Sampling for Vision-Language-Action Models
- 2026Retrieve-then-Steer: Online Success Memory for Test-Time Adaptation of Generative VLAs
- 2025TRACE: A Self-Improving Framework for Robot Behavior Forecasting with Vision-Language Models
- 2026Seeing Farther and Smarter: Value-Guided Multi-Path Reflection for VLM Policy Optimization
- 2026ELASTIC: Efficiently Learning to Adaptively Scale Test-Time Compute for Generative Control Policies