Modelling and validating the multi-agent system behaviour for a washing machine production line

This paper describes the formal modelling and validation of the behaviour of a multi-agent system that integrates the production and quality control processes in a washing machine production line. The modelling, analysis and validation process uses the Petri nets formalism that provides a rigorous and formal language based on its powerful mathematical foundation, supporting the complete verification of the system correctness during the design phase and before to proceed to the deployment phase. The behaviour models of each agent belonging to the system architecture are edited, analysed and simulated in the PnDK framework

Petri nets approach for designing the migration process towards industrial cyber-physical production systems

Presently, many industries are facing strong challenges related to the demand of customized and high-quality products. These pressures lead to internal company's conflicts where current production systems have a rigid structure, forcing the company into a organization stall when a fast product change is required. Therefore, the need to smoothly migrate traditional systems into more feature-rich and cost-effective systems, namely Cyber-Physical Production Systems (CPPS), became a highly discussed topic. PERFoRM project focuses the conceptual transformation of existing production systems towards plug\&produce ones to achieve flexible and reconfigurable manufacturing environments. In particular, the smooth migration process is considered crucial to effectively transpose existing production systems into truly CPPS. This paper describes the use of Petri nets to design the migration process under the PERFoRM perspective, taking advantage of its inherent capabilities to design, analyze, simulate and validate such complex processes.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 680435.info:eu-repo/semantics/publishedVersio

A proposal of an architecture for the coordination level of intelligent machines

The issue of obtaining a practical, structured, and detailed description of an architecture for the Coordination Level of Center for Intelligent Robotic Systems for Sapce Exploration (CIRSSE) Testbed Intelligent Controller is addressed. Previous theoretical and implementation works were the departure point for the discussion. The document is organized as follows: after this introductory section, section 2 summarizes the overall view of the Intelligent Machine (IM) as a control system, proposing a performance measure on which to base its design. Section 3 addresses with some detail implementation issues. An hierarchic petri-net with feedback-based learning capabilities is proposed. Finally, section 4 is an attempt to address the feedback problem. Feedback is used for two functions: error recovery and reinforcement learning of the correct translations for the petri-net transitions

Un système interactif pour le prototypage virtuel coopératif

We present in this thesis the study and implementation of an interactive system for cooperative prototyping of virtual models. These works make use of several technologies from different scientific backgrounds; Virtual Reality is at the crossroads of many disciplines. Our goal is not to replace right now a CAD system with a system such as that we propose in this thesis. Indeed, the power of the machines does not allow yet the management of virtual objects with an accuracy comparable to that of CAD tools. While our system is intuitive and interactive but does not have enough machine power to compete with such precision tools; This precision is however necessary for the industry. This development will be achieved, for sure, but it is more reasonable for the moment to see virtual reality as a complement to CAD.Nous présentons dans ce mémoire l’étude et la réalisation d’un système interactif pour le prototypage coopératif de maquettes virtuelles. Ces travaux font usage de plusieurs technologies issues de milieux scientifiques variés ; la réalité virtuelle n’est elle pas à la croisée des chemins de nombreuses disciplines ? Notre objectif n’est pas de remplacer dès à présent un système de CAO par un système tel que celui que nous proposons dans ce mémoire. En effet, la puissance des machines ne permet pas encore la gestion d’objets virtuels avec une précision comparable à celle des outils de CAO. Certes notre système est intuitif et interactif mais il ne dispose pas d’assez de puissance machine pour rivaliser en précision avec de tels outils ; cette précision est pourtant nécessaire pour l’industrie. Cette évolution se fera, c’est sûr, mais il est pour l’instant plus raisonnable de voir la réalité virtuelle comme un complément de la CAO

Finding errors in the design of a workflow process : a Petri-net-based approach

Workflow management systems facilitate the everyday operation of business processes by taking care of the logistic control of work. In contrast to traditional information systems, they attempt to support frequent changes of the workflows at hand. Therefore, the need for analysis methods to verify the correctness of workflows is becoming more prominent. In this paper we present a method based on Petri nets. This analysis method exploits the structure of the Petri net to find potential errors in the design of the workflow. Moreover, the analysis method allows for the compositional verification of workfIows

Bisimilarity and Behaviour-Preserving Reconfigurations of Open Petri Nets

We propose a framework for the specification of behaviour-preserving reconfigurations of systems modelled as Petri nets. The framework is based on open nets, a mild generalisation of ordinary Place/Transition nets suited to model open systems which might interact with the surrounding environment and endowed with a colimit-based composition operation. We show that natural notions of bisimilarity over open nets are congruences with respect to the composition operation. The considered behavioural equivalences differ for the choice of the observations, which can be single firings or parallel steps. Additionally, we consider weak forms of such equivalences, arising in the presence of unobservable actions. We also provide an up-to technique for facilitating bisimilarity proofs. The theory is used to identify suitable classes of reconfiguration rules (in the double-pushout approach to rewriting) whose application preserves the observational semantics of the net.Comment: To appear in "Logical Methods in Computer Science", 41 page

Stepwise reduction and approximation method for performance analysis of generalized stochastic petri nets

This thesis delves into the performance analysis of generalized stochastic Petri net (GSPN) model by using an approximation method: the Stepwise Reduction and Approximation (SRA) Method. The key point is that we are able to analyze a subnet in isolation by keeping its token flow direction and its sub-throughput equivalent with all the possible tokens entering into the subnet. The thesis first defines various kinds of potentially reducible subnets, subnet selection rules, approximation subnet construction rules, and reduction evaluation rules. Then corresponding to the possible subnets, the approximation method is used stepwisely until the interested measures are found with the global state space reduced. Two GSPN model examples from the literature are analyzed by using the proposed method. The approximation errors are given and discussed. Finally, the conclusions are drawn and future research is discussed

Relay ladder logic and petri nets for discrete event control design : a comparative study

In the 1960\u27s and earlier discrete event systems (DES) were controlled by hardwired electromechanical relay systems. In 1969 an electronic programmable logic controller (PLC) was introduced. PLC\u27s have been programmed utilizing relay ladder logic (RLL). RLL is a graphical programming language with software devices used to emulate electromechanical devices. RLL programs, however, often become large and difficult to understand because its graphical representation of physical switching devices obscures the discrete event dynamics inherent in the process to be controlled. Petri nets are a methodology for modeling discrete event systems (DES). Using a Petri net based controller, a control strategy could be developed that captures the discrete event dynamics of the process. This should result in a control strategy that is much easier to understand, troubleshoot, modify and evaluate