Hierarchical supervisory control for batch processes

A batch process involves a sequence of operations that are carried out on a discrete quantity of material within a piece of operating equipment. A recipe specifies the sequence of operations to be executed and all possible ways the plant can by utilized in order to produce the desired product. In this paper we divide the plant into two sub-systems: processors (units) and transporting system. A hierarchical supervisor is then constructed that solves the deadlock problem for each of these subsystems separately. Deadlock that can arise as a consequence of the combination of these two subsystems is taken care of by the way recipes are modeled. We start by briefly reviewing the plant and recipe models used. Next, we show the construction of a sub-supervisor for the transporting system and a plant supervisor