用大模型生成密集奖励,让机器人长程任务成功率提升超50%。
Generalizable Dense Reward for Long-Horizon Robotic Tasks

- 结合大语言模型与视觉语言模型,自动分解任务并评估进展
- 自认证机制提供每步内在奖励,显著提升分布外任务成功率
- 无需人工调奖,长程任务成功率达新高,尤其适用于复杂场景
现有机器人基础策略主要通过大规模模仿学习训练,虽能力强劲,但在长程任务中常因分布偏移和误差累积而失败。强化学习可微调模型,但需人工设计奖励函数。本文提出VLLR框架,融合(1)基于大语言模型(LLMs)与视觉语言模型(VLMs)的外在奖励,用于任务进度识别;(2)基于策略自认证的内在奖励。该方法利用LLM将任务分解为可验证子任务,VLM估算进度以初始化价值函数,实现简短预热阶段,避免全训练过程高昂推理成本;自认证则在PPO微调全程提供每步内在引导。消融实验表明:基于VLM的价值初始化显著提升任务完成效率,自认证则大幅提高成功率,尤其在分布外任务上表现突出。在CHORES基准测试中,相比预训练策略,成功率达56%绝对提升;在分布内任务上优于当前最优强化学习方法5%;在分布外任务上提升达10%,全程无需人工奖励工程。
原文摘要 · Abstract (English)
Existing robotic foundation policies are trained primarily via large-scale imitation learning. While such models demonstrate strong capabilities, they often struggle with long-horizon tasks due to distribution shift and error accumulation. While reinforcement learning (RL) can finetune these models, it cannot work well across diverse tasks without manual reward engineering. We propose VLLR, a dense reward framework combining (1) an extrinsic reward from Large Language Models (LLMs) and Vision-Language Models (VLMs) for task progress recognition, and (2) an intrinsic reward based on policy self-certainty. VLLR uses LLMs to decompose tasks into verifiable subtasks and then VLMs to estimate progress to initialize the value function for a brief warm-up phase, avoiding prohibitive inference cost during full training; and self-certainty provides per-step intrinsic guidance throughout PPO finetuning. Ablation studies reveal complementary benefits: VLM-based value initialization primarily improves task completion efficiency, while self-certainty primarily enhances success rates, particularly on out-of-distribution tasks. On the CHORES benchmark covering mobile manipulation and navigation, VLLR achieves up to 56% absolute success rate gains over the pretrained policy, up to 5% gains over state-of-the-art RL finetuning methods on in-distribution tasks, and up to $10\%$ gains on out-of-distribution tasks, all without manual reward engineering. Additional visualizations can be found in https://silongyong.github.io/vllr_project_page/
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