LODGE: Joint Hierarchical Task Planning and Learning of Domain Models with Grounded Execution

Abstract: LLMs enable planning from natural language instructions using implicit world knowledge, but often produce flawed plans that require refinement. Instead of directly predicting plans, recent methods aim to learn a problem domain that can be solved for different goal states using classical planners. However, these approaches require significant human feedback to obtain useful models. We address this shortcoming by learning hierarchical domains, where low-level predicates and actions are composed into higher-level counterparts, and by leveraging simulation to validate their preconditions and effects. This hierarchical approach is particularly powerful for long-horizon planning, where LLM-based planning approaches typically struggle. Furthermore, we introduce a central error reasoner to ensure consistency among the different planning levels. Evaluation on two challenging International Planning Competition (IPC) domains and a long-horizon robot manipulation task demonstrates higher planning success rates than state-of-the-art domain synthesis and LLM-modulo planning methods, while constructing high-quality models of the domain. Resources, videos and detailed experiment results are available at https://claudius-kienle.github.io/lodge/.