A Comparative Analysis of Recent Identification Approaches for Discrete‐Event Systems

Abstract

Analogous to the identification of continuous dynamical systems, identification of discrete-event systems (DESs) consists of determining the mathematical model that describes the behaviour of a given ill-known or eventually unknown system from the observation of the evolution of its inputs and outputs. First, the paper overviews identification approaches of DES found in the literature, and then it provides a comparative analysis of three recent and innovative contributions.

An identification method for PLC-based automated Discrete Event Systems

“…Definition 1: An ordinary Petri Net structure G is a bipartite digraph represented by the 4-tuple G = (P,T,I,O) where: P = {p 1 Now it is defined IPN, an extension to PN that allows associating input and output signals to PN models.…”

“…The function of this system is to sort parcels according to their size. It has 9 inputs (signal sensors from the system): a 0 ,a 1 After the identification process and before concurrence transformations, the model shown in Figure 10(b) is obtained. After some transformations considering phenomena described in section IV, the net in Figure 11 is obtained.…”

“…In the context of automated DES, identification methods can be complementary to established modeling techniques; identification builds a closed-loop controller-plant model, which is generally obtained by a synchronous composition operation. Three main approaches for identifying DES have been proposed in literature [1].…”

A relative identification method for reactive systems

“…construction of a model that is understandable by experts to revamp an existing machine; this is also the applicative context of this work. A good survey on DES identication can be found in Estrada-Vargas et al (2010). This survey underlines in particular that an identification method may be absolute (or black-box), when no a priori knowledge about the system behavior is available before identification, or relative otherwise.…”

Automated modelling of reactive discrete event systems from external behavioural data

“…In the context of automated manufacturing systems, identification methods allow obtaining a first model that can be detailed using established modelling techniques and available knowledge of the system; such a model describes the controller-plant behaviour during the closed-loop functioning. Three main approaches for identifying DES have been proposed in literature [4].…”