Current Trends in Automated Planning

representations of future behavior ... usually a set of actions, with temporal and other constraints on them, for execution by some agent or agents.1 One motivation for automated-planning research is theoretical: planning is an important component of rational behavior—so if one objective of artificial intelligence is to grasp the computational aspects of intelligence, then certainly planning plays a critical role. Another motivation is very practical: plans are needed in many different fields of human endeavor, and in some cases it is desirable to create these plans automatically. In this regard, automatedplanning research has recently achieved several notable successes such as the Mars Rovers, software to plan sheet-metal bending operations, and Bridge Baron. The Mars Rovers (see figure 1) were controlled by planning and scheduling software that was developed jointly by NASA’s Jet Propulsion Laboratory and Ames Research Center (Estlin et al. 2003). Software to plan sheet-metal bending operations (Gupta et al. 1998) is bundled with Amada Corporation’s sheet-metal bending machines such as the one shown in figure 2. Finally, software to plan declarer play in the game of bridge helped Bridge Baron to win the 1997 world championship of computer bridge (Smith, Nau, and Throop 1998). The purpose of this article is to summarize the current status of automated-planning research, and some important trends and future directions. The next section includes a conceptual model for automated planning, classifies planning systems into several different types, and compares their capabilities and limitations; and the Trends section discusses directions and trends.