Anna I. Pózna(1*), Miklós Gerzson(2), Adrien Leitold(3), Katalin M. Hangos(4)

(1) Department of Electrical Engineering and Information Systems, University of Pannonia, PO Box 158, Veszprém, 8201, HUNGARY
(2) Department of Electrical Engineering and Information Systems, University of Pannonia, PO Box 158, Veszprém, 8201, HUNGARY
(3) Department of Mathematics, University of Pannonia, PO Box 158, Veszprém, 8201, HUNGARY
(4) Institute for Computer Science and Control, Hungarian Academy of Sciences, PO Box 63, Budapest, 1518, HUNGARY
(*) Corresponding Author

Diagnosis of Technological Systems Based on the Structural Decomposition of their Coloured Petri Net Model


Abstract



Diagnosing faults during the operation of a system is an essential task when investigating technological systems. In this paper, a new online fault identification method is proposed which is based on the occurrence graph of the coloured Petri net model of the system. The model is able to simulate the normal and faulty operations of the system given in the form of event lists, so called traces. The diagnosis is based on the search for deviations between the traces of the normal and the actual operations. In the case of complex technological systems, the occurrence graph can contain hundreds of nodes; therefore, the computational effort and searching-time increase significantly. Our proposed structural decomposition method can manage these demands so it has a crucial impact on the practical application of diagnostic processes. The main idea of our method is that the complex systems can be decomposed into technological units. Therefore, the diagnosis can be done by components separately and the diagnostic result of a unit can be used for the diagnosis of the other units connected to it. Because of the structural decomposition, the diagnosis has to be performed on much smaller occurrence graphs but the effect of faults in previous units is taken into account. The proposed method is illustrated by a simple case study.

Keywords


technological system; diagnosis; coloured Petri net model; structural decomposition; qualitative model

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