A Logical Semantics for PDDL+

TL;DR

This paper introduces a logical semantics for PDDL+ by mapping it to situation calculus, enabling better analysis and planning in hybrid domains with autonomous processes.

Contribution

It provides a novel mapping from PDDL+ to situation calculus, giving PDDL+ a formal logical foundation and enhancing planning capabilities.

Findings

Established a direct mapping between PDDL+ and situation calculus.

Enabled formal analysis of PDDL+ domains using logical methods.

Suggested new approaches for effective planning in hybrid domains.

Abstract

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+.