Synthesis of a Class of Discrete-Event Controllers for Large Manufacturing Systems

A synthesis method is presented for a class of discrete-event controllers employed in large manufacturing systems forcing at most one control action in each stage of the control pattern. The theoretical grounds are provided by a predicate representation of a synthesis framework based on supervisory control theory for arbitrary control patterns. Algorithms are established for synthesizing complete nonblocking controllers. These algorithms are part of a synthesis procedure deployed in an experimental tool using binary decision diagrams. Two examples show how to use the proposed method and its associated tool, highlighting their benefits and disadvantages. The examples also illustrate how to apply the method in order to maintain the modeling simple and to synthesize controllers for manufacturing systems of considerable size that otherwise could not be obtained.