Hierarchical supervisory control for batch processes

A Petri net-based approach for the modeling of batch plants as well as prod ucts is presented. With the focus on synchronization and booking issues, we propose general Petri net building blocks for the construction of recipes. These building blocks prove to be very usable for supervisor synthesis and implementation. We also introduce a hierarchical supervisor structure that implements deadlock avoidance policies when executing a number of concurre nt recipes. It is shown that the presented hierarchical supervisor is by fa r less complex than a nonhierarchical one.