Learning Temporal Task Specifications From Demonstrations

As we progress towards real-world deployment, the critical need for interpretability in reinforcement learning algorithms grows more pivotal, ensuring the safety and reliability of intelligent agents. This paper tackles the challenge of acquiring task specifications in linear temporal logic through expert demonstrations, aiming to alleviate the burdensome task of specification engineering. The rich semantics of temporal logics serve as an interpretable framework for delineating intricate, multi-stage tasks. We propose a method which iteratively learns a task specification and a nominal policy solving this task. In each iteration, the task specification is refined to better distinguish expert trajectories from trajectories sampled from the nominal policy. With this process we obtain a concise and interpretable task specification. Unlike previous work, our method is capable of learning directly from trajectories in the original state space and does not require predefined atomic propositions. We showcase the effectiveness of our method on multiple tasks in both an office and a Minecraft-inspired environment.