A Framework to Generate Neurosymbolic PDDL-compliant Planners

The problem of integrating high-level task planning in the execution loop of a real-world robot architecture remains challenging, as the planning times of traditional symbolic planners explode combinatorially with the number of symbols to plan upon. In this paper, we present Teriyaki, a framework for training Large Language Models (LLMs), and in particular the now well-known GPT-3 model, into neurosymbolic planners compatible with the Planning Domain Definition Language (PDDL). Unlike symbolic approaches, LLMs require a training process. However, their response time scales with the combined length of the input and the output. Hence, LLM-based planners can potentially provide significant performance gains on complex planning problems as the technology matures and becomes more accessible. In this preliminary work, which to our knowledge is the first using LLMs for planning in robotics, we (i) outline a methodology for training LLMs as PDDL solvers, (ii) generate PDDL-compliant planners for two challenging PDDL domains, and (iii) test the planning times and the plan quality associated with the obtained planners, while also comparing them to a state-of-the-art PDDL planner, namely Probe. Results confirm the viability of the approach, with Teriyaki-based planners being able to solve 95.5% of problems in a test data set of 1000 samples, and even generating plans up to 13.5% shorter on average than the employed traditional planner, depending on the domain.