An Approach to Temporal Planning and Scheduling in Domains with Predictable Exogenous Events

TL;DR

This paper presents a novel approach for temporal planning in domains with predictable exogenous events, integrating constraint-based temporal reasoning into a graph-based framework to improve planning efficiency and quality.

Contribution

It introduces a new method combining temporal reasoning with graph-based planning using local search, specifically addressing exogenous events at known times.

Findings

Effective in IPC-4 competition with improved CPU-time

Produces higher quality plans with temporal constraints

Demonstrates robustness in handling predictable exogenous events

Abstract

The treatment of exogenous events in planning is practically important in many real-world domains where the preconditions of certain plan actions are affected by such events. In this paper we focus on planning in temporal domains with exogenous events that happen at known times, imposing the constraint that certain actions in the plan must be executed during some predefined time windows. When actions have durations, handling such temporal constraints adds an extra difficulty to planning. We propose an approach to planning in these domains which integrates constraint-based temporal reasoning into a graph-based planning framework using local search. Our techniques are implemented in a planner that took part in the 4th International Planning Competition (IPC-4). A statistical analysis of the results of IPC-4 demonstrates the effectiveness of our approach in terms of both CPU-time and plan quality. Additional experiments show the good performance of the temporal reasoning techniques integrated into our planner.