ResearchResearch paperReinforcement Learning · Robotics & Embodied AI1 source · Oct 6, 2026

QF3: Fast Flow RL with Filtered Q-Gradients

We introduce QF3 (Fast Flow RL with Filtered Q-Gradients), an online off-policy RL algorithm that trains a flow policy with flow matching plus the critic's action gradient, backpropagated through a one-step prediction of the flow's output.

Key points

  • Flow policies have become a standard policy class for learning robot behaviors from demonstrations, but reinforcement learning is still critical for improving pre-trained flow policies or learning them from scratch through interaction.
  • To keep updates where the critic and this prediction are reliable, QF3 applies the critic gradient only to action dimensions that stay near the replay action.
  • To our knowledge, QF3 is the first off-policy flow RL method to train humanoid locomotion policies from scratch and transfer them zero-shot to hardware.
  • We further apply QF3 to fine-tune pretrained flow-based manipulation policies on both ABC-Sim and Robomimic tasks.

Sources (1)

  • [1]QF3: Fast Flow RL with Filtered Q-Gradients
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 6, 05:59 PM
    We introduce QF3 (Fast Flow RL with Filtered Q-Gradients), an online off-policy RL algorithm that trains a flow policy with flow matching plus the critic's action gradient, backpropagated through a one-step prediction of the flow's output.
    Flow policies have become a standard policy class for learning robot behaviors from demonstrations, but reinforcement learning is still critical for improving pre-trained flow policies or learning them from scratch through interaction.

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Before this

  1. Oct 6, 20264D-HOF: Hand-Object Flow Matching for Feed-Forward 4D Interaction Reconstruction
  2. Oct 6, 2026Denoising Hierarchical Representations: Joint Continuous Diffusion for Language Modeling
  3. Oct 6, 2026FlowCF: Sparse Counterfactual Explanations for Mixed-Type Tabular Data using Flow Matching
  4. Oct 6, 2026Cylindrical Geodesic Flow Matching for Quasiperiodic Physiological Signal Transformation
  5. Oct 6, 2026Sensor Geometry as a Flow-Matching Prior for Multi-Channel Brain Signals
  6. Oct 6, 2026StairVLA: Stage-Aware Hierarchical Action Generation for Vision-Language-Action Models

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