提出新方法让智能体更高效完成长程目标,避免奖励欺骗问题。
Locally-Guided Actor-Critic: Training a Goal-conditioned Actor with a Subgoal-aware Critic

- 用中间目标显式指导价值估计,提升学习效率
- 在复杂任务中相比其他方法表现最优,成功率更高
- 适合需要长序列规划的强化学习场景
目标导向强化学习在长时序、稀疏奖励场景下表现不佳。现有方法如基于想象中间目标的正则化(RIS)可能导致目标链问题,而基于潜在奖励的形状(PBRS)可能在终止状态产生误导性奖励。本文首先提出一种新奖励形状方法(RS),消除此类欺骗性奖励,但放弃理论保证;随后提出局部引导的演员-评论家(LG-AC),显式将价值估计与完整中间目标序列对齐,通过子目标条件值函数之和建模,支持密集的回溯重标注。在具有挑战性的目标链任务上,实验表明行动正则化与传统奖励形状方法在特定场景下性能下降,而LG-AC在多数任务中实现最佳表现。
原文摘要 · Abstract (English)
Goal-conditioned reinforcement learning struggles with long horizons when rewards are sparse. While a planner can provide subgoals to guide a low-level policy, its use at test time may introduce practical subgoal management difficulties. An alternative paradigm utilizes a high-level planner to assist learning, while the policy remains conditioned only on the final goal, enabling planner-free deployment. Among these methods, Reinforcement Learning with Imagined Subgoals (RIS) introduces a regularization term that encourages the policy to take the same actions for the final goal as it does for an intermediate goal. This regularization, however, may lead to goal-chaining issues when intermediate goals are low-dimensional. Potential-based reward shaping (PBRS) translates plans into an additional reward while ensuring that the optimal policy remains unchanged. Yet, it can generate deceptive rewards in terminal states. We study these failure cases and first propose an alternative reward shaping method (RS) that removes these deceptive rewards at the expense of theoretical guarantees of PBRS. Similar to this RS variant, we then propose another method named Locally-Guided Actor Critic (LG-AC) that rewards the agent for reaching intermediate goals. Unlike RS, where intermediate rewards are implicit in the shaping signal, we explicitly condition a value estimator on the full sequence of intermediate goals but represent the value function as a sum of subgoal-conditioned value functions, enabling dense hindsight relabeling. We evaluate all these methods in tasks with challenging goal-chaining requirements and empirically highlight specific cases in which either action regularization or reward shaping yield low performance, while LG-AC achieves the best overall performance across tasks.
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