A temporal planning system for durative actions of PDDL2.1

Many planning domains have temporal features that can be expressed using durations associated with actions. Unfortunately, the conservative model of actions used in many existing temporal planners is not adequate for some domains which require more expressive models. Level 3 of PDDL2.1 introduces a model of durative actions that includes local conditions and effects to be satisfied at different times during the execution of the actions, thereby giving the planner greater freedom to exploit concurrent actions. This paper presents a temporal planning system which combines the principles of Graphplan and TGP in order to plan with such actions. Although the system is consequently more complex than TGP, the experimental results demonstrate it remains feasible as a way to deal with durative actions.