Contribution to the monitoring of manufacturing systems with time constraints: Application to a surface treatment line

The aim of this paper is the study and the design of a monitoring module based on P-time Petri nets (P-TPN) for manufacturing job-shops with time constraints. In such systems, operation times are included between a minimum and a maximum value. The monitoring consists in a set of two collaborative PNs. The first is used for modeling of normal behavior of the system by temporal spectrum of the marking. The second model, Synchronized Fuzzy Petri Nets (SinFPN), corresponds to monitoring activities. This paper proposes failures modeling and process monitoring for a flexible manufacturing system with time constrains, using a P-TPN sand SincFPN. A monitoring approach based on fuzzy model able to integrate alarm signals and the moment of appearance of the external events in the supervised system is presented. The aim of this original approach is to show how the detection of the occurrence/persistence of the monitored external events could make the supervision more efficient by performing an early diagnosis. It is illustrated step by step on an example of a line surface treatment.