Closed-loop matrix based model of discrete event systems for machine logic control design

This paper deals with modeling, dynamic description, and control of discrete event systems (DES) for production systems and machines control logic design. The control logic of such systems is considered as DES, which is then modeled by a matrix representation of Petri net graph. The dynamics of a DES is described by a well known algebraic Petri net next-state equation and a novel logical firing event selecting equation. The control of the DES dynamics is introduced by logical signals, which represent conditions for occurrence of events. Such a presentation enables closed-loop modeling of DES, which is important for simulation of the systems and analysis of their performance before the target system is actually built. The proposed method is illustrated with a cutting machine application. Using the proposed method, the correct functionality as well as faults response can be simulated with Matlab/Simulink.