用人类纠正动作和代理奖励联合训练,提升强化学习对齐性。
Reinforcement Learning From Imperfect Corrective Actions And Proxy Rewards
- 通过迭代循环获取人类纠正动作并融入价值函数,增强偏好对齐。
- 在不同不完美度的代理奖励下,样本效率优于基线方法。
- 可容忍人类反馈不完美,适合需要人类参与的高风险场景。
实践中,强化学习(RL)代理常使用可能存在偏差的代理奖励函数,导致人机对齐问题——学习策略可能收敛到低累积奖励的非最优性能,或虽获得高奖励但行为不符合期望。为此,本文提出一种新框架,允许人类标注者在代理演示轨迹上提供稀疏的纠正动作,表达其动作偏好,尽管这些反馈也可能不完美。针对此设定,我们设计了基于值函数的深度强化学习算法ICoPro,包含三个阶段:(1) 从人类标注者处收集稀疏纠正动作;(2) 使用边界损失将纠正动作融入Q函数,强制遵循标注者偏好;(3) 使用标准RL损失与边界损失联合训练代理,以学习代理奖励并传播来自人类反馈的价值。此外,引入目标Q网络的伪标签以减少人工成本并稳定训练。在多种任务(Atari游戏与高速公路自动驾驶)上验证表明,无论代理奖励存在何种程度的不完美,本方法均能更好对齐人类偏好且样本效率更高;面对不同类型不完美的纠正动作,仍可通过代理奖励引导克服反馈偏差。
原文摘要 · Abstract (English)
In practice, reinforcement learning (RL) agents are often trained with a possibly imperfect proxy reward function, which may lead to a human-agent alignment issue (i.e., the learned policy either converges to non-optimal performance with low cumulative rewards, or achieves high cumulative rewards but in undesired manner). To tackle this issue, we consider a framework where a human labeler can provide additional feedback in the form of corrective actions, which expresses the labeler's action preferences although this feedback may possibly be imperfect as well. In this setting, to obtain a better-aligned policy guided by both learning signals, we propose a novel value-based deep RL algorithm called Iterative learning from Corrective actions and Proxy rewards (ICoPro), which cycles through three phases: (1) Solicit sparse corrective actions from a human labeler on the agent's demonstrated trajectories; (2) Incorporate these corrective actions into the Q-function using a margin loss to enforce adherence to labeler's preferences; (3) Train the agent with standard RL losses regularized with a margin loss to learn from proxy rewards and propagate the Q-values learned from human feedback. Moreover, another novel design in our approach is to integrate pseudo-labels from the target Q-network to reduce human labor and further stabilize training. We experimentally validate our proposition on a variety of tasks (Atari games and autonomous driving on highway). On the one hand, using proxy rewards with different levels of imperfection, our method can better align with human preferences and is more sample-efficient than baseline methods. On the other hand, facing corrective actions with different types of imperfection, our method can overcome the non-optimality of this feedback thanks to the guidance from proxy reward.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。