Analysis of hierarchical control architectures: a Petri net approach

Petri nets have been shown to be quite powerful in specifying the control logic for hierarchical systems. Each level of the hierarchy may be modeled by one or more Petri nets. Each Petri net receives tokens from only one higher-level Petri net. Also, any two adjacent Petri nets (in the same level) may pass tokens only through the immediately-higher-level Petri net. Some results concerning the analysis of this type of hierarchical Petri net structures are shown. The authors concentrate on the conservativeness property