用可解释性增强强化学习,让智能体关注关键状态特征。
SHAP-Guided Kernel Actor-Critic for Explainable Reinforcement Learning
- 基于核方法与SHAP的可解释性框架,动态加权状态特征重要性。
- 在连续控制任务中实现更高训练稳定性与效率,且能给出状态贡献度。
- 适合需要透明决策过程的高风险领域,如医疗或金融自动化。
Actor-critic(AC)方法是强化学习的核心,但解释性有限。现有可解释强化学习方法通常忽略状态特征的差异性影响,对所有状态维度一视同仁。本文提出基于再生核希尔伯特空间(RKHS)与SHAP的先进双时标AC算法(RSA2C),包含动作器、价值评论家和优势评论家。动作器在带马哈拉诺比加权算子核的向量值RKHS中实现,价值评论家与优势评论家则位于标量RKHS中。三者使用稀疏字典:价值评论家独立维护字典,动作器与优势评论家共享一个。通过RKHS-SHAP计算状态归因(基于流形内与流形外条件均值嵌入),转换为马哈拉诺比门控权重,调节动作器梯度与优势评论家目标。理论推导出在状态扰动下的全局非渐近收敛界,证明了稳定性与效率。三个连续控制环境的实验证明,RSA2C在效率、稳定性和可解释性上均有显著提升。代码已开源于https://github.com/Na-Li66/RSA2C。
原文摘要 · Abstract (English)
Actor-critic (AC) methods are a cornerstone of reinforcement learning (RL) but offer limited interpretability. Current explainable RL methods seldom use state attributions to assist training. Rather, they treat all state features equally, thereby neglecting the heterogeneous impacts of individual state dimensions on the reward. We propose RKHS-SHAP-based Advanced Actor-Critic (RSA2C), an attribution-aware, kernelized, two-timescale AC algorithm, including Actor, Value Critic, and Advantage Critic. The Actor is instantiated in a vector-valued reproducing kernel Hilbert space (RKHS) with a Mahalanobis-weighted operator-valued kernel, while the Value Critic and Advantage Critic reside in scalar RKHSs. These RKHS-enhanced components use sparsified dictionaries: the Value Critic maintains its own dictionary, while the Actor and Advantage Critic share one. State attributions, computed from the Value Critic via RKHS-SHAP (kernel mean embedding for on-manifold and conditional mean embedding for off-manifold expectations), are converted into Mahalanobis-gated weights that modulate Actor gradients and Advantage Critic targets. We derive a global, non-asymptotic convergence bound under state perturbations, showing stability through the perturbation-error term and efficiency through the convergence-error term. Empirical results on three continuous-control environments show that RSA2C achieves efficiency, stability, and interpretability. Our code is available at https://github.com/Na-Li66/RSA2C.
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