Message-oriented decomposition for supervisory control in manufacturing system

Supervisory control in manufacturing systems is achieved through messages b etween the supervisory controller and processing devices. This paper presen ts a message-oriented model for supervisory control. The model supports rea listic states for processing stations and some material handling devices. T he major characteristics of the model are the decomposition of the system i nto small state models for components that cooperate via messaging as well as the algebraic manipulation for state progression. This paper also presen ts a definition of controllability meaningful in the design and analysis of supervisory control systems. The modeling and analysis are illustrated wit h a flow line example and a robotic cell example. (C) 1999 Elsevier Science Ltd. All rights reserved.