Domain-independent planning Representation and plan generation

摘要

A domain-independent planning program that supports both automatic and interactive generation of hierarchical, partially ordered plans is described. An improved formalism makes extensive use of constraints and resources to represent domains and actions more powerfully. The formalism also offers efficient methods for representing properties of objects that do not change over time, allows specification of the plan rationale (which includes scoping of conditions and appropriately relating different levels in the hierarchy), and provides the ability to express deductive rules for deducing the effects of actions. The implications of allowing parallel actions in a plan or problem solution are discussed, and new techniques for efficiently detecting and remedying harmful parallel interactions are presented. The most important of these techniques, reasoning about resources, is emphasized and explained. The system supports concurrent exploration of different branches in the search, making best-first search easy to implement.