Paper Overview
Field: Robotics Authors: Langzhe Gu, Chengkai Hou, Meng Li et al. (17 authors) Released: 2026-08-17 arXiv: 2608.16837
Background
Humanoid robots hold great promise as general-purpose agents in human-centered environments, yet generalist vision-language-action (VLA) foundation models are not readily applicable to humanoid whole-body loco-manipulation. Two key bottlenecks exist:
- The high dimensionality and interdependence of humanoid motions make it difficult for conventional single-stage VLA architectures to coordinate locomotion, waist posture, and dual-arm manipulation.
- Policies trained via offline behavior cloning can remain suboptimal at deployment, while direct online RL fine-tuning of large VLA backbones demands excessive computation and poses safety risks during real-robot exploration.
- HAF-VLA: a hierarchical action flow generator built on a pretrained flow-matching VLA. It splits whole-body action denoising into three stages, preserving kinematic dependencies and avoiding incoherent one-shot generation of whole-body actions.
- HAF-Steer: a latent offline-to-online RL pipeline stacked on top of the frozen HAF-VLA. It leverages flow-matching invertibility and DCT-based dimensionality reduction to confine RL optimization to a compact noise subspace, enabling safe and efficient online refinement.
Method: HAF (Humanoid Adaptation Framework)
HAF consists of two components that transfer off-the-shelf generalist VLA foundation models to humanoid whole-body loco-manipulation:
Results
Across seven real-world humanoid loco-manipulation tasks, HAF outperforms naive single-stage VLA baselines.
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*Auto-collected on 2026-08-19.*