Policy Learning from Large Vision-Language Model Feedback without Reward Modeling

Fuente: arXiv
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Autori principali: Luu, Tung M., Lee, Donghoon, Lee, Younghwan, Yoo, Chang D.
Natura: Preprint
Pubblicazione: 2025
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author Luu, Tung M.
Lee, Donghoon
Lee, Younghwan
Yoo, Chang D.
author_facet Luu, Tung M.
Lee, Donghoon
Lee, Younghwan
Yoo, Chang D.
contents Offline reinforcement learning (RL) provides a powerful framework for training robotic agents using pre-collected, suboptimal datasets, eliminating the need for costly, time-consuming, and potentially hazardous online interactions. This is particularly useful in safety-critical real-world applications, where online data collection is expensive and impractical. However, existing offline RL algorithms typically require reward labeled data, which introduces an additional bottleneck: reward function design is itself costly, labor-intensive, and requires significant domain expertise. In this paper, we introduce PLARE, a novel approach that leverages large vision-language models (VLMs) to provide guidance signals for agent training. Instead of relying on manually designed reward functions, PLARE queries a VLM for preference labels on pairs of visual trajectory segments based on a language task description. The policy is then trained directly from these preference labels using a supervised contrastive preference learning objective, bypassing the need to learn explicit reward models. Through extensive experiments on robotic manipulation tasks from the MetaWorld, PLARE achieves performance on par with or surpassing existing state-of-the-art VLM-based reward generation methods. Furthermore, we demonstrate the effectiveness of PLARE in real-world manipulation tasks with a physical robot, further validating its practical applicability.
format Preprint
id arxiv_https___arxiv_org_abs_2507_23391
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Policy Learning from Large Vision-Language Model Feedback without Reward Modeling
Luu, Tung M.
Lee, Donghoon
Lee, Younghwan
Yoo, Chang D.
Machine Learning
Robotics
Offline reinforcement learning (RL) provides a powerful framework for training robotic agents using pre-collected, suboptimal datasets, eliminating the need for costly, time-consuming, and potentially hazardous online interactions. This is particularly useful in safety-critical real-world applications, where online data collection is expensive and impractical. However, existing offline RL algorithms typically require reward labeled data, which introduces an additional bottleneck: reward function design is itself costly, labor-intensive, and requires significant domain expertise. In this paper, we introduce PLARE, a novel approach that leverages large vision-language models (VLMs) to provide guidance signals for agent training. Instead of relying on manually designed reward functions, PLARE queries a VLM for preference labels on pairs of visual trajectory segments based on a language task description. The policy is then trained directly from these preference labels using a supervised contrastive preference learning objective, bypassing the need to learn explicit reward models. Through extensive experiments on robotic manipulation tasks from the MetaWorld, PLARE achieves performance on par with or surpassing existing state-of-the-art VLM-based reward generation methods. Furthermore, we demonstrate the effectiveness of PLARE in real-world manipulation tasks with a physical robot, further validating its practical applicability.
title Policy Learning from Large Vision-Language Model Feedback without Reward Modeling
topic Machine Learning
Robotics
url https://arxiv.org/abs/2507.23391