ScoRe-Flow: Complete Distributional Control via Score-Based Reinforcement Learning for Flow Matching

Fuente: arXiv
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Main Authors: Qiu, Xiaotian, Chen, Lukai, Li, Jinhao, Sun, Qi, Zhuo, Cheng, Dai, Guohao
Format: Preprint
Published: 2026
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_version_ 1866917402062618624
author Qiu, Xiaotian
Chen, Lukai
Li, Jinhao
Sun, Qi
Zhuo, Cheng
Dai, Guohao
author_facet Qiu, Xiaotian
Chen, Lukai
Li, Jinhao
Sun, Qi
Zhuo, Cheng
Dai, Guohao
contents Flow Matching (FM) policies have emerged as an efficient backbone for robotic control, offering fast and expressive action generation that underpins recent large-scale embodied AI systems. However, FM policies trained via imitation learning inherit the limitations of demonstration data; surpassing suboptimal behaviors requires reinforcement learning (RL) fine-tuning. Recent methods convert deterministic flows into stochastic differential equations (SDEs) with learnable noise injection, enabling exploration and tractable likelihoods, but such noise-only control can compromise training efficiency when demonstrations already provide strong priors. We observe that modulating the drift via the score function, i.e., the gradient of log-density, steers exploration toward high-probability regions, improving stability. The score admits a closed-form expression from the velocity field, requiring no auxiliary networks. Based on this, we propose ScoRe-Flow, a score-based RL fine-tuning method that combines drift modulation with learned variance prediction to achieve decoupled control over the mean and variance of stochastic transitions. Experiments demonstrate that ScoRe-Flow achieves 2.4x faster convergence than flow-based SOTA on D4RL locomotion tasks and up to 5.4% higher success rates on Robomimic and Franka Kitchen manipulation tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2604_10962
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ScoRe-Flow: Complete Distributional Control via Score-Based Reinforcement Learning for Flow Matching
Qiu, Xiaotian
Chen, Lukai
Li, Jinhao
Sun, Qi
Zhuo, Cheng
Dai, Guohao
Robotics
I.2.6; I.2.9
Flow Matching (FM) policies have emerged as an efficient backbone for robotic control, offering fast and expressive action generation that underpins recent large-scale embodied AI systems. However, FM policies trained via imitation learning inherit the limitations of demonstration data; surpassing suboptimal behaviors requires reinforcement learning (RL) fine-tuning. Recent methods convert deterministic flows into stochastic differential equations (SDEs) with learnable noise injection, enabling exploration and tractable likelihoods, but such noise-only control can compromise training efficiency when demonstrations already provide strong priors. We observe that modulating the drift via the score function, i.e., the gradient of log-density, steers exploration toward high-probability regions, improving stability. The score admits a closed-form expression from the velocity field, requiring no auxiliary networks. Based on this, we propose ScoRe-Flow, a score-based RL fine-tuning method that combines drift modulation with learned variance prediction to achieve decoupled control over the mean and variance of stochastic transitions. Experiments demonstrate that ScoRe-Flow achieves 2.4x faster convergence than flow-based SOTA on D4RL locomotion tasks and up to 5.4% higher success rates on Robomimic and Franka Kitchen manipulation tasks.
title ScoRe-Flow: Complete Distributional Control via Score-Based Reinforcement Learning for Flow Matching
topic Robotics
I.2.6; I.2.9
url https://arxiv.org/abs/2604.10962