Diverse Planning with Simulators via Linear Temporal Logic
Mustafa F. Abdelwahed, Alice Toniolo, Joan Espasa, Ian P. Gent
TL;DR
The paper tackles the limitation of single-solution planning in complex, non-symbolic environments by introducing FBI_LTL, a simulator-based diverse planner that encodes semantic diversity with Linear Temporal Logic (LTL). It integrates a modified Iterated Width search with LTL-based novelty constraints to generate semantically distinct plans, demonstrated on PDDLGym, Puzznic, and NASim benchmarks. Key contributions include the FBI_LTL algorithm, an LTL-based behaviour-space model with cost-bound and goal-order features, and empirical evidence that semantically diverse planning improves coverage across diverse domains. This work advances planning in realistic, non-symbolic domains by enabling agents to select among multiple meaningful strategies rather than a single solution.
Abstract
Autonomous agents rely on automated planning algorithms to achieve their objectives. Simulation-based planning offers a significant advantage over declarative models in modelling complex environments. However, relying solely on a planner that produces a single plan may not be practical, as the generated plans may not always satisfy the agent's preferences. To address this limitation, we introduce $\texttt{FBI}_\texttt{LTL}$, a diverse planner explicitly designed for simulation-based planning problems. $\texttt{FBI}_\texttt{LTL}$ utilises Linear Temporal Logic (LTL) to define semantic diversity criteria, enabling agents to specify what constitutes meaningfully different plans. By integrating these LTL-based diversity models directly into the search process, $\texttt{FBI}_\texttt{LTL}$ ensures the generation of semantically diverse plans, addressing a critical limitation of existing diverse planning approaches that may produce syntactically different but semantically identical solutions. Extensive evaluations on various benchmarks consistently demonstrate that $\texttt{FBI}_\texttt{LTL}$ generates more diverse plans compared to a baseline approach. This work establishes the feasibility of semantically-guided diverse planning in simulation-based environments, paving the way for innovative approaches in realistic, non-symbolic domains where traditional model-based approaches fail.
