arXiv:2411.14457cs.LG2024-11被引 3

用不确定性感知的LLM指导强化学习,提升决策可靠性。

Guiding Reinforcement Learning Using Uncertainty-Aware Large Language Models

  • 通过蒙特卡洛丢弃法评估LLM预测方差,增强建议可信度。
  • 动态熵调节策略使模型在不确定时降低对LLM的依赖,提升训练鲁棒性。
  • 适用于需要高可靠决策的复杂任务,如机器人路径规划。

人类在强化学习中的指导因成本和时间限制,在大规模应用中不切实际。大型语言模型(LLMs)有望缓解强化学习样本效率低的问题,并可能替代人类教练。然而,将LLMs作为训练者面临挑战,因其在序列任务中表现过度自信且解决方案不可靠。本文提出一种校准引导系统,利用蒙特卡洛丢弃法通过多次前向传播评估预测方差,以提升LLM建议的可靠性。同时,设计了一种基于动态模型平均熵的新型策略塑造方法,根据引导不确定性动态调整LLM对强化学习策略的影响。该方法确保了在可靠引导下进行稳健的强化学习训练。为验证贡献,我们在包含三个目标的Minigrid环境中进行了大量实验,结果表明性能优于未经校准的LLM、无引导的RL以及采用不同塑造策略的校准LLM。此外,我们分析了多种不确定性估计方法,证明平均熵能有效反映错误引导中的更高不确定性。研究揭示了微调后LLM的持续过度自信问题,强调了在序列决策任务中有效校准的重要性。

原文摘要 · Abstract (English)

Human guidance in reinforcement learning (RL) is often impractical for large-scale applications due to high costs and time constraints. Large Language Models (LLMs) offer a promising alternative to mitigate RL sample inefficiency and potentially replace human trainers. However, applying LLMs as RL trainers is challenging due to their overconfidence and less reliable solutions in sequential tasks. We address this limitation by introducing a calibrated guidance system that uses Monte Carlo Dropout to enhance LLM advice reliability by assessing prediction variances from multiple forward passes. Additionally, we develop a novel RL policy shaping method based on dynamic model average entropy to adjust the LLM's influence on RL policies according to guidance uncertainty. This approach ensures robust RL training by relying on reliable LLM guidance. To validate our contributions, we conduct extensive experiments in a Minigrid environment with three goals in varying environment sizes. The results showcase superior model performance compared to uncalibrated LLMs, unguided RL, and calibrated LLMs with different shaping policies. Moreover, we analyze various uncertainty estimation methods, demonstrating the effectiveness of average entropy in reflecting higher uncertainty in incorrect guidance. These findings highlight the persistent overconfidence in fine-tuned LLMs and underscore the importance of effective calibration in sequential decision-making problems.

强化学习大模型不确定性

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