On-line Planning and Scheduling in a High-speed Manufacturing Domain

We describe a simple manufacturing domain that requires integrated planning and scheduling and report on our experience adapting existing techniques to this domain. The setting is on-line in the sense that additional jobs arrive asynchronously, perhaps several per second, while plans for previous jobs are being executed. While challenging, the domain is also forgiving: feasible schedules can be found quickly, suboptimal plans are acceptable, and plan execution is relatively reliable. An approach based on temporal state-space planning with constraint-based resource handling suffices for small to medium-sized instances of the problem, and our current implementation successfully controls two prototype plants. By integrating planning and scheduling, we enable high productivity even for complex plants.