Real-time Shop Floor Control Implementations in BUFAIM Model Factory

摘要

This paper describes two real-time Shop Floor Control (SFC) implementations for the model factory in Bogazici University Flexible Automation and Intelligent Manufacturing Laboratory (BUFAIM). The model factory serves as an infrastructure for on-going research in BUFAIM; therefore, it is essential that the SFC software for the real-time management of orders and resources is developed in an open, modular, reusable and extendible fashion. Two different SFC architectures are implemented using the object-oriented methodology: The layered approach adopts the hybrid-hierarchical architecture where the SFC system is accomplished in three-the shop, cell and equipment-levels. The Shop Controller is a discrete event based system adapted from a simulator previously developed in BUFAIM for FMS design and performance evaluation. The distributed approach adopts the heterarchical architecture such that orders and resources are designed as autonomous agents (holons) which communicate via a negotiation mechanism based on Contract-Net protocol. The two approaches are compared based on several implementation aspects. Both SFC systems are under continuous development to incorporate new hardware as the model factory expands, and new decision types and tools to enhance performance.