Simulation-based shop floor control

This paper presents an overview of simulation-based shop floor control. Much of the work described is based on research conducted in the Computer Integrated Manufacturing (CIM) Lab at The Pennsylvania State University, the Texas A&M Computer Aided Manufacturing Lab (TAMCAM), Technion in Israel, and the University of Arizona CIM lab over the past decade. In this approach, a discrete event simulation is used not only as a traditional analysis and evaluation tool but also as a task generator that drives shop floor operations in real time. To enable this, a special feature of the Arena™ simulation language was used whereby the simulation model interacts directly with a shop floor execution system by sending and receiving messages. This control simulation reads process plans and master production orders from external data-bases that are updated by a process planning system and coordinated via an external business system. The control simulation also interacts with other external programs such as a planner, a scheduler, and an error detection and recovery function. In this paper, the architecture, implementation, and the integration of all the components of the proposed simulation-based control system are described in detail. Finally, extensions to this approach, including automatic model generation, are described.