In the actual industrial world context, companies have to deal with a rising demand of customized products that would match the current society needs. This challenge requires to be extremely flexible, fast and efficient in findings new solutions in order to remain competitive. Every modification in an existing and functioning system could lead to a slowdown or even a stop of the production, with the consequent time and economic losses. The ability to develop a system model allows the company to analyze the current situation, evaluate several possible new strategies and perform a simulation that gives as results some useful information that could be taken into consideration in the decision phase. When it comes to modify and improve a manufacturing system, it is necessary to include the possible human-machine interactions that currently occur; these two entities often use a different language, one hardly comprehensible to the other. This fact brings out the need of a precise and universal language, through the use of an accurate and comprehensive semantic. It is in order to respond to these needs that ontologies recently emerged as a valid solution to system modelling and simulation, leading to guarantees a proper semantic structure that allows a universal understanding. A Systematic Literature Review shows how ontologies are currently used to perform system reconfiguration and data management, but points out the existence of a gap of work regarding the use of them in order to analyze the status of components in the system and the consequent criticality analysis that could leads to a feasibility evaluation. This thesis proposes a new ontology that models an existing Flexible Manufacturing Line through a two-step methodology starting from the creation of a Unified Modelling Language (UML) class diagram and its subsequent translation into Ontology Web Language (OWL). The resulting ontology allows to perform a product feasibility analysis by taking into account the current status of the involved components of the line, proposing a new type of application for ontologies in industry. This ontology results useful when it comes to reconfigure a manufacturing line and the definition of a new production plan, by bringing out which products are currently feasible and which are not, finally allowing the evaluation of different plans with the objective of defining the one that matches the actual requests and needs.
Nell’attuale contesto industriale mondiale, le aziende devono fronteggiare una crescente domanda di prodotti personalizzati, la quale rispecchia le richieste della società odierna. Questa sfida richiede una grande flessibilità, velocità ed efficienza nel trovare nuove soluzioni che permettano di rimanere competitivi. Ogni modifica ad un impianto già esistente e funzionante può portare al rallentamento, se non all’interruzione, della produzione, con le conseguenti perdite economiche e temporali. L’abilità di sviluppare un modello di un sistema permette all’azienda di analizzare la situazione attuale, valutare diverse possibili nuove strategie ed eseguire una simulazione che dia come risultato delle informazioni utili che possano essere prese in considerazione nella fase decisionale. Quando si tratta di modificare e migliorare un impianto di produzione, è necessario non dimenticare l’eventuale interazione uomo-macchine attualmente presente; queste due entità usano spesso un linguaggio differente, uno difficilmente comprensibile all’altro. Questo aspetto evidenzia la necessità di un nuovo linguaggio puntiglioso ma universale, reso possibile attraverso l’uso di una semantica precisa e completa. Le ontologie sono recentemente emerse come una valida soluzione a queste necessità, in quanto utili per modellare e simulare un sistema, ma anche in grado di garantire un’adeguata struttura semantica che permetta una comprensione universale. Una revisione sistematica della letteratura mostra come le ontologie siano attualmente usate per supportare la riconfigurazione di sistemi a la gestione dei dati, ma evidenzia una mancanza di approfondimento riguardo al loro possibile uso con scopi come l’analisi dello stato dei componenti del sistema, la conseguente valutazione di criticità e l’analisi di fattibilità di un prodotto. Questa tesi propone una nuova ontologia che modella una linea di produzione flessibile esistente attraverso un approccio a due fasi, partendo dalla creazione di un diagramma a classi in Unified Modelling Language (UML) e concludendo con la sua trasposizione in Ontology Web Language (OWL). L’ontologia risultante permette di realizzare un’analisi di fattibilità di prodotto, prendendo in considerazione l’attuale stato dei componenti della linea richiesti, mostrando un nuovo possibile ambito di applicazione per le ontologie. Questa ontologia risulta essere utile in caso di riconfigurazione di una linea esistente, o in caso di definizione di un nuovo piano di produzione, evidenziando quali prodotti siano al momento realizzabili e quali no, permettendo quindi la valutazione di diversi scenari con lo scopo di definirne uno che risponda al meglio alle attuali esigenze.
Ontology modelling of a flexible manufacturing line to verify the production logic for product feasibility
Balacchi, Alessio
2019/2020
Abstract
In the actual industrial world context, companies have to deal with a rising demand of customized products that would match the current society needs. This challenge requires to be extremely flexible, fast and efficient in findings new solutions in order to remain competitive. Every modification in an existing and functioning system could lead to a slowdown or even a stop of the production, with the consequent time and economic losses. The ability to develop a system model allows the company to analyze the current situation, evaluate several possible new strategies and perform a simulation that gives as results some useful information that could be taken into consideration in the decision phase. When it comes to modify and improve a manufacturing system, it is necessary to include the possible human-machine interactions that currently occur; these two entities often use a different language, one hardly comprehensible to the other. This fact brings out the need of a precise and universal language, through the use of an accurate and comprehensive semantic. It is in order to respond to these needs that ontologies recently emerged as a valid solution to system modelling and simulation, leading to guarantees a proper semantic structure that allows a universal understanding. A Systematic Literature Review shows how ontologies are currently used to perform system reconfiguration and data management, but points out the existence of a gap of work regarding the use of them in order to analyze the status of components in the system and the consequent criticality analysis that could leads to a feasibility evaluation. This thesis proposes a new ontology that models an existing Flexible Manufacturing Line through a two-step methodology starting from the creation of a Unified Modelling Language (UML) class diagram and its subsequent translation into Ontology Web Language (OWL). The resulting ontology allows to perform a product feasibility analysis by taking into account the current status of the involved components of the line, proposing a new type of application for ontologies in industry. This ontology results useful when it comes to reconfigure a manufacturing line and the definition of a new production plan, by bringing out which products are currently feasible and which are not, finally allowing the evaluation of different plans with the objective of defining the one that matches the actual requests and needs.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/169284