Synthesis and implementation of local modular supervisory control for a manufacturing cell

Abstract

Supervisory control theory is applied to a manufacturing cell commanded by a programmable logic controller (PLC). By means of a local modular approach -a methodology that exploits modularity of the plant and of the behavioral specifications models - optimal supervisors are obtained without state-space explosion. For the purpose of simplifying the ladder diagram implementation in the PLC, reduced supervisors are implemented in a three level structure that executes modular supervisor concurrent action and interfaces the theoretical model with the real system. The flexible and productive manufacturing cell behavior, after practical implementation of the control system, and the final PLC code readability and flexibility are positive quality indicators to the applied methodology.