A DES-THEORY BASED HYBRID SUPERVISORY CONTROL-SYSTEM FOR MANUFACTURING SYSTEMS

Manufacturing systems generally encompass processes that are discrete in time and space. Among the variety of real-time supervisory control techniques reported in the literature, controlled-automata-based discr ete event system (DES) theory is one of the few with mathematical form alism. However, the control of even a moderately complex system using this theory may require avery large control strategy. To attempt to co pe with this problem, a hybrid supervisory controller was developed th at splits operations between a DES-theory-based supervisory controller and an alternate mechanism. The alternate mechanism reroutes part pro duction in real time whenever a priori unmodeled events occur. This mo dified approach provides a significantly more efficient controller tha n could be attained using solely a DES-theory-based supervisory contro ller.