A Logical Semantics for PDDL+
This work addresses a foundational gap in automated planning formalisms, offering a logical framework that could facilitate analysis and comparisons, though it appears incremental as it builds on existing theories like hybrid automata and situation calculus.
The paper tackles the lack of a logical semantics for PDDL+, an extension of PDDL2.1 used for modeling mixed discrete-continuous domains, by proposing a mapping between PDDL+ and the situation calculus based on hybrid automata, thereby providing PDDL+ with a logical semantics and enabling new planning approaches.
PDDL+ is an extension of PDDL2.1 which incorporates fully-featured autonomous processes and allows for better modelling of mixed discrete-continuous domains. Unlike PDDL2.1, PDDL+ lacks a logical semantics, relying instead on state-transitional semantics enriched with hybrid automata semantics for the continuous states. This complex semantics makes analysis and comparisons to other action formalisms difficult. In this paper, we propose a natural extension of Reiter's situation calculus theories inspired by hybrid automata. The kinship between PDDL+ and hybrid automata allows us to develop a direct mapping between PDDL+ and situation calculus, thereby supplying PDDL+ with a logical semantics and the situation calculus with a modern way of representing autonomous processes. We outline the potential benefits of the mapping by suggesting a new approach to effective planning in PDDL+.