Message-oriented decomposition for modeling supervisory control in manufacturing system

Supervisory control in manufacturing systems is achieved through messages between the supervisory controller and the manufacturing components. The paper presents a message-oriented model for supervisory control. The model supports realistic states for processing stations and some material handling devices. The major characteristics of the model are the decomposition of the system into small state models for components that cooperate via messaging as well as the algebraic manipulation for state progression. The paper also presents a definition of controllability meaningful in the design and analysis of supervisory control systems.