An operational approach for the control of manufacturing processes

The purpose of this paper is that of formalizing a unique decisional framework to state different problems relevant to automated manufacturing systems, such as production planning, material requirements planning, and on-line management. As the manufacturing systems are modelled as discrete-event systems, the (timed) Petri net formalism can be adopted to represent their dynamics; moreover, in order to make the decisional problems addressed computationally tractable, it is assumed that the manufacturing systems can be represented by means of a particular class of timed Petri nets, the Timed Event Graphs. Two particular optimization problems are discussed in the paper. The first one is relevant to the minimization of production and inventory costs, while satisfying a pre-specified production demand, whereas the second one refers to an on-line management problem in which the deviations between the actual system behaviour and a pre-defined nominal behaviour are sought to be minimized.