A hybrid shop-floor control system for food manufacturing

This paper describes research in the area of hybrid control using simulation including a suitable architecture and a test-bed developed for experimenting with hybrid manufacturing systems – that is, manufacturing systems containing both continuous and discrete processing activities. The paper builds on the RapidCIM control system developed at Penn State University and makes innovations in this work including integrating continuous simulation and discrete event simulation into a message-based process control system. Simulation technology is extended to support real-time communication to access remote databases, and pass messages, which are used to control hardware equipment performing both continuous processes and discrete activities. This makes possible the development of a generic hybrid control capability. In RapidCIM, software is automatically generated to control and coordinate the physical system. This can substantially reduce the cost of developing and integrating such systems, and allows a detailed simulation to be used for both analysis as well as for control. An experimental research prototype of such a hybrid control system has been constructed for the Pennsylvania State University Creamery, in which unit processes and operational decisions are integrated.