An automated flow line control system design

An automated flow line (AFL) applies equipment for production where parts follow the same path to have their operations in sequence. Unlike other flexible manufacturing systems, the flow line often operates in a synchronous mode. Thereby, by considering the design of a flow line control system, attention can be given to the control protocol that can address the interactions between equipment. Historically, the control protocol has been developed in a relatively complex form. In this paper, we propose a systematic approach for designing an AFL control system from a simple protocol. Pertaining to the part transfer this protocol includes four patterns, whose combinations are capable of demonstrating the line's control down to the equipment level. Since the entire line may not be short and its processes may not be similar, there could exist several control sections corresponding to different portions of the line. A modified hierarchical control architecture is selected. This proposed control system development approach has been applied to a color monitor tube (CMT) factory. A small real case illustrates the details. Furthermore, since equipment is not always in a normal condition, exception-handling with respect to the control protocol is also briefly discussed.