Trace - DC Hierarchical Supervisory

We present a hierarchical control theory for supervisory automata based on state aggregation. Conditions are determined on state partitions which ensure that the control of transitions between blocks in a high-level (i.e. aggregated) model, combined with local state-dependent controls, is eeective in the sense of achieving speciications given either for the high-level model or for the low-level system. A design methodology is proposed for the construction of the necessary partitions. We show this formulation of hierarchical supervision satisses the consistency conditions in the existing language-based hierarchical supervisory control theory. Examples are presented including a material transfer line with re-entrant ow and a double queue.