Time Disturbances and Filtering of Sensors Signals in Tolerant Multi-product Job-shops with Time Constraints

This paper deals with supervision in critical time manufacturing jobshops without assembling tasks. Such systems have a robustness property to deal with time disturbances. A filtering mechanism of sensors signals integrating the robustness values is proposed. It provides the avoidance of control freezing if the time disturbance is in the robustness intervals. This constitutes an enhancement of the filtering mechanism since it makes it possible to continue the production in a degraded mode providing the guarantees of quality and safety. When a symptom of abnormal functioning is claimed by the filtering mechanism, it is imperative to localize the time disturbance occurrence. Based upon controlled P-time Petri nets as a modeling tool, a series of lemmas are quoted in order to build a theory dealing with the localization problem.

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Fuzzy Filtering of Sensors Signals in Manufacturing Systems with Time Constraints

International Journal of Computers Communications & Control ◽

10.15837/ijccc.2010.3.2488 ◽

2010 ◽

Vol 5 (3) ◽

pp. 362 ◽

Cited By ~ 6

Author(s):

Anis M’halla ◽

Nabil Jerbi ◽

Simon Collart Dutilleul ◽

Etienne Craye ◽

Mohamed Benrejeb

Keyword(s):

Fuzzy Systems ◽

Manufacturing Systems ◽

Knowledge Integration ◽

Expert Knowledge ◽

Time Constraints ◽

Quality And Safety ◽

Job Shops ◽

New Approach ◽

Robustness Property ◽

Filtering Approach

The presented work is dedicated to the supervision of manufacturing job-shops with time constraints. Such systems have a robustness property towards time disturbances. The main contribution of this paper is a fuzzy filtering approach of sensors signals integrating the robustness values. This new approach integrates a classic filtering mechanism of sensors signals and fuzzy logic techniques. The strengths of these both techniques are taken advantage of the avoidance of control freezing and the capability of fuzzy systems to deal with imprecise information by using fuzzy rules. Finally, to demonstrate the effectiveness and accuracy of this new approach, an example is depicted. The results show that the fuzzy approach allows keeping on producing, but in a degraded mode, while providing the guarantees of quality and safety based on expert knowledge integration.

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P-Time Petri Nets for Manufacturing Systems with Staying Time Constraints

IFAC Proceedings Volumes ◽

10.1016/s1474-6670(17)43571-3 ◽

1997 ◽

Vol 30 (6) ◽

pp. 1487-1492 ◽

Cited By ~ 2

Author(s):

Soizick Calvez ◽

Pascal Aygalinc ◽

Wael Khansa

Keyword(s):

Petri Nets ◽

Manufacturing Systems ◽

Time Constraints ◽

Time Petri Nets ◽

Staying Time

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Decision Tools Regarding Time Constraints Violation in Manufacturing Workshops

International Journal of Computers Communications & Control ◽

10.15837/ijccc.2021.3.4240 ◽

2021 ◽

Vol 16 (3) ◽

Author(s):

Nabil Jerbi ◽

Simon Collart-Dutilleul

Keyword(s):

Theoretical Result ◽

Manufacturing System ◽

Time Constraints ◽

Simultaneous Occurrence ◽

Time Petri Nets ◽

Decision Tool ◽

Robustness Property ◽

Decision Tools ◽

Two Delays ◽

Operation Duration

This paper is dedicated to the study of constraints violation in manufacturing workshops with time constraints. In such systems, every operation duration is included between minimal and maximal values. P-time Petri nets are used for modeling. A new theorem is introduced, constituting a decision tool about the occurrence of constraints violation at the level of a synchronization transition when various types of time disturbances occur. It shows the robustness properties of a manufacturing system on a range that may include delay and advance disturbances. The theoretical result is illustrated step by step on a given workshop. Two other lemmas are elaborated contributing to the study of the constraints violation problem. The final goal is to generalize the robustness property towards simultaneous occurrence of two delays at two points of the system, each having its own robustness range.

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Cost Problems for Parametric Time Petri Nets*

Fundamenta Informaticae ◽

10.3233/fi-2021-2083 ◽

2022 ◽

Vol 183 (1-2) ◽

pp. 97-123

Author(s):

Didier Lime ◽

Olivier H. Roux ◽

Charlotte Seidner

Keyword(s):

Petri Nets ◽

Software Tool ◽

Convex Polyhedra ◽

Time Constraints ◽

Time Petri Nets ◽

Parameter Synthesis ◽

Mere Existence ◽

Parameter Values ◽

Explicit Enumeration ◽

Symbolic Constraints

We investigate the problem of parameter synthesis for time Petri nets with a cost variable that evolves both continuously with time, and discretely when firing transitions. More precisely, parameters are rational symbolic constants used for time constraints on the firing of transitions and we want to synthesise all their values such that some marking is reachable, with a cost that is either minimal or simply less than a given bound. We first prove that the mere existence of values for the parameters such that the latter property holds is undecidable. We nonetheless provide symbolic semi-algorithms for the two synthesis problems and we prove them both sound and complete when they terminate. We also show how to modify them for the case when parameter values are integers. Finally, we prove that these modified versions terminate if parameters are bounded. While this is to be expected since there are now only a finite number of possible parameter values, our algorithms are symbolic and thus avoid an explicit enumeration of all those values. Furthermore, the results are symbolic constraints representing finite unions of convex polyhedra that are easily amenable to further analysis through linear programming. We finally report on the implementation of the approach in Romeo, a software tool for the analysis of time Petri nets.

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Fuzzy Monitoring Approach Based on P-time Petri Nets of manufacturing Systems with Time Constraints

2020 17th International Multi-Conference on Systems, Signals & Devices (SSD) ◽

10.1109/ssd49366.2020.9364121 ◽

2020 ◽

Author(s):

Mouhaned Gaied ◽

Anis M'halla ◽

Kamel Ben Othmen

Keyword(s):

Petri Nets ◽

Manufacturing Systems ◽

Time Constraints ◽

Time Petri Nets

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Distributed Monitoring Based on P-Time Petri Nets and Chronicle Recognition of the Tunisian Railway Network

Journal of Electrical and Computer Engineering ◽

10.1155/2020/6265379 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Anis M’halla ◽

Dimitri Lefebvre ◽

Mouhaned Gaied

Keyword(s):

Petri Nets ◽

Discrete Event ◽

Time Constraints ◽

Time Petri Nets ◽

Distributed Monitoring ◽

Railway Network ◽

Traffic Incidents ◽

Event System ◽

Railway Networks

This paper falls under the problems of the monitoring of a Discrete Event System (DES) with time constraints. Among the various techniques used for online and distributed monitoring, we are interested in the chronicle recognition. Chronicles are temporal patterns that represent the system’s possible evolutions. The proposed models are based on P-time Petri nets that are suitable to represent with accuracy and modularity the Tunisian railway network. These models are scalable and may be used to represent a large variety of railway networks. Then, monitoring is based on the generation of chronicles that are suitable to detect and isolate traffic incidents in a distributed setting. Consequently, the proposed approach is tractable for large networks. Finally, to demonstrate the effectiveness and accuracy of the approach, an application to the case study of the Tunisian railway network is outlined.

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