Dissertations / Theses: 'Flexible manufacturing systems'

1

Scott, Wesley Dane. "A flexible control system for flexible manufacturing systems." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/158.

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A flexible workcell controller has been developed using a three level control hierarchy (workcell, workstation, equipment). The cell controller is automatically generated from a model input by the user. The model consists of three sets of graphs. One set of graphs describes the process plans of the parts produced by the manufacturing system, one set describes movements into, out of and within workstations, and the third set describes movements of parts/transporters between workstations. The controller uses an event driven Petri net to maintain state information and to communicate with lower level controllers. The control logic is contained in an artificial neural network. The Petri net state information is used as the input to the neural net and messages that are Petri net events are output from the neural net. A genetic algorithm was used to search over alternative operation choices to find a "good" solution. The system was fully implemented and several test cases are described.

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2

Salzman, Rhonda A. (Rhonda Ann) 1978. "Manufacturing system design : flexible manufacturing systems and value stream mapping." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/82697.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
by Rhonda A. Salzman.
S.M.

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3

ONORI, RICCARDO. "Managing distributed flexible manufacturing systems." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2005. http://hdl.handle.net/2108/181.

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Per molti anni la ricerca scientifica si è concentrata sui diversi aspetti di gestione dei sistemi manifatturieri, dall’ottimizzazione dei singoli processi produttivi, fino alla gestione delle più complesse imprese virtuali. Tuttavia molti aspetti inerenti il coordinamento e il controllo, ancora presentano problematiche rilevanti in ambito industriale e temi di ricerca aperti. L’applicazione di tecnologie avanzate e di strumenti informatici evoluti non riesce da sola a garantire il successo nelle funzioni di controllo e di integrazione. Al fine di ottenere un alto grado di efficienza, è necessario supportare tali tecnologie e strumenti con dei modelli che siano in grado di rappresentare le funzionalità e i processi dei sistemi manifatturieri, e consentano di prevederne e gestirne l’evoluzione. Ne emerge l’esigenza di politiche di controllo e di gestio ne distribuite, che favoriscano l’auto-organizzazione e la cooperazione nei sistemi manifatturieri. I sistemi manifatturieri flessibili distribuiti (DFMS), in risposta a tale esigenza, sono sistemi di produzione dinamici in grado di garantire una risposta in tempo reale alla allocazione ottima delle risorse, e organizzare efficientemente le lavorazioni dei prodotti. In questa tesi viene proposta una modellizzazione a livelli per tali sistemi. Secondo tale rappresentazione un DFMS può essere visto come un grafo strutturato su più livelli, tale che: i vertici del grafo rappresentano le risorse interagenti nel sistema; ogni nodo di un livello rappresenta a sua volta un livello successivo. Partendo da questa rappresentazione, sono stati quindi sviluppati due modelli per lo studio dell’allocazione ottima delle risorse (task mapping) e per l’organizzazione di lavorazioni (task scheduling) che richiedono l’uso simultaneo di risorse condivise nel sistema. Il task mapping problem consiste nella suddivisione bilanciata di un certo insieme di lavorazioni tra le risorse del sistema. In questa tesi si è studiato il caso in cui le lavorazioni sono omogenee, non presentano vincoli di precedenza, ma necessitano di un certo volume di comunicazione tra le risorse cui sono assegnate per garantirne il coordinamento, incidendo in tal senso sulla complessità di gestione. L’analisi critica dei modelli che sono tipicamente usati in letteratura per rappresentare tale problema, ne hanno posto in evidenza l’inadeguatezza. Attraverso alcuni risultati teorici si è quindi dimostrato come il problema possa ricondursi ad un hypergraph partitioning problem. Studiando la formulazione matematica di tali problemi, e limitandosi al caso di due risorse produttive, si è infine giunti alla determinazione di una buona approssimazione sulla soluzione ottima. Il problema di sequenziamento delle lavorazioni (task scheduling) che richiedono l’uso simultaneo di risorse condivise è stato trattato nel caso specifico di celle robotizzate. E’ stata quindi dimostrata l’NP-completezza di questo problema ed è stata progettata una euristica di soluzione, validandone i risultati in diversi scenari produttivi.
For several years, research has focused on several aspects of manufacturing, from the individual processes towards the management of virtual enterprises, but several aspects, like coordination and control, still have relevant problems in industry and remain challenging areas of research. The application of advanced technologies and informational tools by itself does not guarantee the success of control and integration applications. In order to get a high degree of integration and efficiency, it is necessary to match the technologies and tools with models that describe the existing knowledge and functionality in the system and allow the correct understanding of its behaviour. In a global and wide market competition, the manufacturing systems present requirements that lead to distributed, self-organised, co-operative and heterogeneous control applications. A Distributed Flexible Manufacturing System (DFMS) is a goal-driven and data-directed dynamic system which is designed to provide an effective operation sequence for the products to fulfil the production goals, to meet real-time requirements and to optimally allocate resources. In this work first a layered approach for modeling such production systems is proposed. According to that representation, a DFMS may be seen as multi-layer resource-graph such that: vertices on a layer represent interacting resources; a layer at level l is represented by a node in the layer at level (l-1). Then two models are developed concerning with two relevant managerial issues in DFMS, the task mapping problem and the task scheduling with multiple shared resources problem. The task mapping problem concerns with the balanced partition of a given set of jobs and the assignment of the parts to the resources of the manufacturing system. We study the case in which the jobs are quite homogeneous, do not have precedence constraints, but need some communications to be coordinated. So, jobs assignment to different parts causes a relevant communication effort between those parts, increasing the managerial complexity. We show that the standard models usually used to formal represent such a problem are wrong. Through some graph theoretical results we relate the problem to the well-known hypergraph partitioning problem and briefly survey the best techniques to solve the problem. A new formulation of the problem is then presented. Some considerations on an improved version of the formulation permit the computation of a good Lower Bound on the optimal solution in the case of the hypergraph bisection. The task scheduling with multiple shared resources problem is addressed for a robotic cell. We study the general problem of sequencing multiple jobs, where each job consists of multiple ordered tasks and tasks execution requires simultaneous usage of several resources. NP-completeness results are given. A heuristic with a guarantee approximation result is designed and evaluated.

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4

Washington, Lisa Anne. "Effectiveness analysis of flexible manufacturing systems." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15317.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1985.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.
Bibliography: leaves 112-114.
by Lisa Anne Washington.
M.S.

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5

Dadone, Paolo. "Fuzzy Control of Flexible Manufacturing Systems." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36531.

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Flexible manufacturing systems (FMS) are production systems consisting of identical multipurpose numerically controlled machines (workstations), automated material handling system, tools, load and unload stations, inspection stations, storage areas and a hierarchical control system. The latter has the task of coordinating and integrating all the components of the whole system for automatic operations. A particular characteristic of FMSs is their complexity along with the difficulties in building analytical models that capture the system in all its important aspects. Thus optimal control strategies, or at least good ones, are hard to find and the full potential of manufacturing systems is not completely exploited.

The complexity of these systems induces a division of the control approaches based on the time frame they are referred to: long, medium and short term. This thesis addresses the short-term control of a FMS. The objective is to define control strategies, based on system state feedback, that fully exploit the flexibility built into those systems. Difficulties arise since the metrics that have to be minimized are often conflicting and some kind of trade-offs must be made using "common sense". The problem constraints are often expressed in a rigid and "crisp" way while their nature is more "fuzzy" and the search for an analytical optimum does not always reflect production needs. Indeed, practical and production oriented approaches are more geared toward a good and robust solution.

This thesis addresses the above mentioned problems proposing a fuzzy scheduler and a reinforcement-learning approach to tune its parameters. The learning procedure is based on evolutionary programming techniques and uses a performance index that contains the degree of satisfaction of multiple and possibly conflicting objectives. This approach addresses the design of the controller by means of language directives coming from the management, thus not requiring any particular interface between management and designers.

The performances of the fuzzy scheduler are then compared to those of commonly used heuristic rules. The results show some improvement offered by fuzzy techniques in scheduling that, along with ease of design, make their applicability promising. Moreover, fuzzy techniques are effective in reducing system congestion as is also shown by slower performance degradation than heuristics for decreasing inter- arrival time of orders. Finally, the proposed paradigm could be extended for on-line adaptation of the scheduler, thus fully responding to the flexibility needs of FMSs.

Master of Science

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6

Scott, Peter. "Craft skills in flexible manufacturing systems." Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377776.

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7

Chen, Yufeng. "Optimal supervisory control of flexible manufacturing systems." Thesis, Paris, CNAM, 2015. http://www.theses.fr/2015CNAM0990/document.

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Notre thèse est consacrée à l’étude de la supervision des réseaux de Petri en vue de la conception de systèmes manufacturiers flexibles. L’objectif est la définition de stratégies de pilotage en ligne pour l’évitement de conflits et d’interblocages, dans le cadre de la théorie de la supervision. Le point de départ de notre travail est d’exploiterle graphe de marquage du réseau de Petri, ce qui permet en particulier d’obtenir des stratégies de commande maximalement permissive pour des problèmes d’évitement de conflits et d’interblocages. Nous avons ainsi introduit des techniques originales, manipulations d’inégalités ou réductions d’ensembles de marquages, destinées à diminuerla complexité algorithmique d’une telle méthode. Dans premier temps, nous avons focalisé sur la synthèse de superviseurs dits purs, ce qui correspond au cas particulier où l’ensemble de marquage légaux, est convexe.Cette optimisation est ensuite considérée du point de vue de la facilité de mise en oeuvre. Nous traitons ainsi de la minimisation de la structure du superviseur et de son coût d’implémentation en préservant une structure de supervision qui offre à la fois la permissivité maximale et une complexité de calcul raisonnable en vue d’utilisationsur des installations réelles. Aussi, nous avons cherché à réduire le nombre de places de contrôle nécessaires pour réaliser un superviseur maximalement permissif, pour cela nous avons formule le calcul du nombre minimal de places de contrôle en termes d’un problème de programmation linéaire. Afin d’affaiblir la complexité de ce calcul de superviseur, deux versions de l’algorithme sont proposées. Ce problème de minimisation de la taille dusuperviseur, quoique fondamental, n’est pas abordé aussi directement dans la littérature. Il s’agit là d’une première contribution.Dans u second temps, nous nous sommes intéressés aux réseaux de Petri à boucles (self-loops). Les boucles étant représentées par une variable qui s’ajoute dans la contrainte inégalité définissant l’ensemble de marquages légaux. Après avoir proposé une méthode de réduction du nombre d’inégalités ainsi que du superviseur optimalen se basant sur les approches et résultats précédents, nous avons établi une condition suffisante d’obtention d’un superviseur maximalement permissif permettant de traiter des ensembles de marquages légaux non convexes.Enfin nous proposons une méthode de synthèse de contrôleur pour une nouvelle classe de réseaux de Petri, avec des arcs inhibiteurs correspondant à des contraintes définies par des intervalles. La taille du contrôleur ainsi obtenu et défini en termes d’arcs inhibiteurs à intervalles s’en trouve réduite ainsi que par conséquent sont coût d’implémentation
Reachability graph analysis is an important technique for deadlockcontrol, which always suffers from a state explosion problem since it requires togenerate all or a part of reachable markings.Based on this technique, an optimal or suboptimal supervisor with high behavioralpermissiveness can always be achieved. This thesis focuses on designing liveness enforcing Petri net supervisors for FMSs by considering their behavioralpermissiveness, supervisory structure, and computationnal complexity.The following research contributions are made in this thesis.1. The design of a maximally permissive liveness-enforcing supervisor for an FMSis proposed by solving integer linear programming problems (ILPPs).2. Structural complexity is also an important issue for a maximally permissivePetri net supervisor. A deadlock prevention policy for FMSs is proposed, which canobtain a maximally permissive liveness-enforcing Petri net supervisor while thenumber of control places is compressed.3. In order to overcome the computational complexity problem in MCPP and ensurethat the controlled system is maximally permissive with a simple structure, wedevelop an iterative deadlock prevention policy and a modified version.4. We consider the hardware and software costs in the stage of controlimplementation of a deadlock prevention policy, aiming to obtain a maximallypermissive Petri net supervisor with the lowest implementation cost. A supervisorconsists of a set of control places and the arcs connecting control places totransitions. We assign an implementation cost for each control place and controland observation costs for each transition. Based on reachability graph analysis,maximal permissiveness can be achieved by designing place invariants that prohibitall FBMs but no legal markings.5. Self-loops are used to design maximally permissive supervisors. A self-loop ina Petri net cannot be mathematically represented by its incidence matrix. Wepresent a mathematical method to design a maximally permissive Petri netsupervisor that is expressed by a set of control places with self-loops. A controlplace with a self-loop can be represented by a constraint and a selfloopassociated with a transition whose firing may lead to an illegal marking

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8

Gupta, Avaneesh. "Characterization and measurement of manufacturing flexibility for production planning in high mix low volume manufacturing system /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?IEEM%202004%20GUPTA.

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9

Zhang, Wenle. "Scalable deadlock avoidance algorithms for flexible manufacturing systems." Ohio : Ohio University, 2000. http://www.ohiolink.edu/etd/view.cgi?ohiou1179862449.

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10

Roth, Aleda V. "Strategic planning for the optimal acquisition of flexible manufacturing systems technology." Connect to resource, 1986. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1262794556.

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11

Hsu, Chih-hua. "Dynamic scheduling of manufacturing systems /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

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12

Chen, Yufeng. "Optimal supervisory control of flexible manufacturing systems." Electronic Thesis or Diss., Paris, CNAM, 2015. http://www.theses.fr/2015CNAM0990.

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Notre thèse est consacrée à l’étude de la supervision des réseaux de Petri en vue de la conception de systèmes manufacturiers flexibles. L’objectif est la définition de stratégies de pilotage en ligne pour l’évitement de conflits et d’interblocages, dans le cadre de la théorie de la supervision. Le point de départ de notre travail est d’exploiterle graphe de marquage du réseau de Petri, ce qui permet en particulier d’obtenir des stratégies de commande maximalement permissive pour des problèmes d’évitement de conflits et d’interblocages. Nous avons ainsi introduit des techniques originales, manipulations d’inégalités ou réductions d’ensembles de marquages, destinées à diminuerla complexité algorithmique d’une telle méthode. Dans premier temps, nous avons focalisé sur la synthèse de superviseurs dits purs, ce qui correspond au cas particulier où l’ensemble de marquage légaux, est convexe.Cette optimisation est ensuite considérée du point de vue de la facilité de mise en oeuvre. Nous traitons ainsi de la minimisation de la structure du superviseur et de son coût d’implémentation en préservant une structure de supervision qui offre à la fois la permissivité maximale et une complexité de calcul raisonnable en vue d’utilisationsur des installations réelles. Aussi, nous avons cherché à réduire le nombre de places de contrôle nécessaires pour réaliser un superviseur maximalement permissif, pour cela nous avons formule le calcul du nombre minimal de places de contrôle en termes d’un problème de programmation linéaire. Afin d’affaiblir la complexité de ce calcul de superviseur, deux versions de l’algorithme sont proposées. Ce problème de minimisation de la taille dusuperviseur, quoique fondamental, n’est pas abordé aussi directement dans la littérature. Il s’agit là d’une première contribution.Dans u second temps, nous nous sommes intéressés aux réseaux de Petri à boucles (self-loops). Les boucles étant représentées par une variable qui s’ajoute dans la contrainte inégalité définissant l’ensemble de marquages légaux. Après avoir proposé une méthode de réduction du nombre d’inégalités ainsi que du superviseur optimalen se basant sur les approches et résultats précédents, nous avons établi une condition suffisante d’obtention d’un superviseur maximalement permissif permettant de traiter des ensembles de marquages légaux non convexes.Enfin nous proposons une méthode de synthèse de contrôleur pour une nouvelle classe de réseaux de Petri, avec des arcs inhibiteurs correspondant à des contraintes définies par des intervalles. La taille du contrôleur ainsi obtenu et défini en termes d’arcs inhibiteurs à intervalles s’en trouve réduite ainsi que par conséquent sont coût d’implémentation
Reachability graph analysis is an important technique for deadlockcontrol, which always suffers from a state explosion problem since it requires togenerate all or a part of reachable markings.Based on this technique, an optimal or suboptimal supervisor with high behavioralpermissiveness can always be achieved. This thesis focuses on designing liveness enforcing Petri net supervisors for FMSs by considering their behavioralpermissiveness, supervisory structure, and computationnal complexity.The following research contributions are made in this thesis.1. The design of a maximally permissive liveness-enforcing supervisor for an FMSis proposed by solving integer linear programming problems (ILPPs).2. Structural complexity is also an important issue for a maximally permissivePetri net supervisor. A deadlock prevention policy for FMSs is proposed, which canobtain a maximally permissive liveness-enforcing Petri net supervisor while thenumber of control places is compressed.3. In order to overcome the computational complexity problem in MCPP and ensurethat the controlled system is maximally permissive with a simple structure, wedevelop an iterative deadlock prevention policy and a modified version.4. We consider the hardware and software costs in the stage of controlimplementation of a deadlock prevention policy, aiming to obtain a maximallypermissive Petri net supervisor with the lowest implementation cost. A supervisorconsists of a set of control places and the arcs connecting control places totransitions. We assign an implementation cost for each control place and controland observation costs for each transition. Based on reachability graph analysis,maximal permissiveness can be achieved by designing place invariants that prohibitall FBMs but no legal markings.5. Self-loops are used to design maximally permissive supervisors. A self-loop ina Petri net cannot be mathematically represented by its incidence matrix. Wepresent a mathematical method to design a maximally permissive Petri netsupervisor that is expressed by a set of control places with self-loops. A controlplace with a self-loop can be represented by a constraint and a selfloopassociated with a transition whose firing may lead to an illegal marking

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13

丘杰 and Jie Qiu. "Scheduling flexible manufacturing systems using fuzzy heuristics." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31244671.

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14

Doulgeri, Z. "Production scheduling policy for flexible manufacturing systems." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/38292.

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15

Altobelli, Frank Robert. "Flexible manufacturing systems and the housing industry." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43352.

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16

Granados, Fernández Víctor Hugo. "Modelling and optimization of flexible manufacturing systems." Master's thesis, Instituto Politécnico de Bragança, Escola Superior de Tecnologia e Gestão, 2012. http://hdl.handle.net/10198/7982.

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The Lagrangian relaxation method for solving a Mixed-Integer Linear Problem was implemented in order to improve the current TEMPO-PSI team exible manufacturing system solutions, available at the AIP-primeca pole in University of Valenciennes, France. The MILP optimization model, from TEMPO-PSI team, can not guarantee good results when the amount of jobs in the manufacturing system increases due to the growth in the number of variables of the model. A study on the optimization model was conducted with the objective to nd the candidate constraints for Lagrangian relaxation. A comparative study is made between the initial model solutions and Lagrange-relaxed model solutions. The results of the present research indicate that the use of the Lagrangian relaxation method on the scheduling problems could have advantages in obtaining better solutions. Um método relaxação lagrangeana para resolver um problema de Programação Misto- Inteira Linear foi implementado com o objetivo de melhorar as soluções actuais dos sistemas de manufatura exíveis da equipa TEMPO-PSI, disponível no laboratório AIPprimeca da Universidade de Valenciennes, França. O modelo de optimização MILP, da equipa TEMPO-PSI, não consegue garantir bons resultados quando a quantidade de operações no sistema de manufactura aumenta, devido ao crescimento do número de variáveis do modelo. O estudo do modelo de optimização foi levado a cabo com o objectivo de encontrar as restrições candidatas para a relaxação Lagrangeana. O estudo comparativo é feito entre as soluções iniciais do modelo e as soluções do modelo relaxado com o método de Lagrange. Os resultados da presente investigação indicam que o uso de método da relaxação Lagrangeana nos problemas de escalonamento de tarefas poderá ter vantagens na obtenção de melhores soluções.

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Whitehead, Jonathan David. "Scheduling and layout in flexible manufacturing systems." Thesis, University of Southampton, 2002. https://eprints.soton.ac.uk/50617/.

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This thesis covers a variety of inter-related scheduling and layout issues encountered in flexible manufacturing systems. The principal focus is upon systems which adopt the commonly implemented loop layout configuration. A pivotal idea behind the work is that products must revisit machines during their manufacture. The work encompasses both computational and theoretical results. The computational work consists of testing both new and standard heuristic and local search techniques on two strongly NP-hard combinatorial optimisation problems, one related to layout and the other to single machine scheduling. In the layout problem, machines must be sequenced around a loop of conveyor belt with the objective of minimising the amount of movement carried out by the worst affected product type within the manufacturing system. In the single machine scheduling problem, coupledoperation jobs must be scheduled so that the maximum completion time on the machine, the makespan, is minimised; each coupled-operation job consists of two arbitrary processing time operations separated by a time lag that is bounded both below and above. Our results suggest that local search techniques, while well suited to standard search spaces, do not perform well when the search space contains infeasible neighbours and the cost of evaluating candidate solutions is high. The theoretical work stems from the repetitive manufacture of single product types in loop layout flexible manufacturing systems. We demonstrate that in such a system, the efficiency is strongly governed by the balance of workloads on the machines. We develop mixed integer programming models for tool allocation and machine sequencing with the objective of balancing workloads, and as a secondary criterion, minimising product movement. Focusing on a single machine, we study the computational complexity of a class of coupled-operation scheduling problems; each job consists of two unit processing time operations separated by a fixed delay of two units of time, and their order of production is restricted by precedence constraints. For several standard scheduling objective functions, we provide either polynomial algorithms or proof of NP-hardness for parallel chain and tree precedence constraints.

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Ozbayrak, M. "Design of tool management systems for flexible manufacturing systems." Thesis, Loughborough University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359905.

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19

Ng, Koon-hung, and 吳冠雄. "Dynamic process planning for flexible manufacturing cells." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31240823.

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Ng, Koon-hung. "Dynamic process planning for flexible manufacturing cells /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22029709.

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21

Mansour, Mohammad Ahmad Chaudhry Ghulam M. "A generalized simulation model for flexible manufacturing system." Diss., UMK access, 2005.

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Thesis (Ph. D.)--School of Computing and Engineering and Dept. of Mathematics. University of Missouri--Kansas City, 2005.
"A dissertation in engineering and mathematics." Advisor: Ghulam Chaudhry. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed June 26, 2006. Includes bibliographical references (leaves 341-346 ). Online version of the print edition.

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Ma, Xiaonan. "An approach to measure manufacturing system flexibility /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?IELM%202007%20MA.

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Özbolat, Nida Kamil Süel Akın. "The debate on the transition to flexible production:A case study on manufacturing industry in Turkey and its provinces/." s.l.]: [s.n.], 2003. http://library.iyte.edu.tr/tezler/master/sehirplanlama/T000275.rar.

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Pardasani, Ajit Carleton University Dissertation Information and Systems Science. "Network flow optimization models for integrated flexible manufacturing systems." Ottawa, 1989.

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Feng, Jiejian. "Issues in assemble-to-order systems /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?IELM%202006%20FENG.

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Ozpeynirci, Selin. "Allocation And Tooling Decisions In Flexible Manufacturing Systems." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12609161/index.pdf.

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In this thesis, we consider a capacity allocation problem in flexible manufacturing systems. We assume limited time and tool magazine capacities on the Computer Numerically Controlled (CNC) machines. We have a set of operations that have to be assigned to the machines and each operation requires a set of tools to be processed. Our problem is to allocate the available capacity of the CNC machines to operations and their required tools. We consider two problems in this study: maximizing the total weight of operations where there are a limited number of tools of each type available and maximizing total weight minus total tooling cost where the tools can be used or purchased at a cost. We model the problems as Integer Linear Programs and show that they are NP-hard in the strong sense. For the total weight problem, we propose upper bounds, branch and bound algorithm for exact solutions and several heuristics for approximate solutions. For the bicriteria problem, we use Lagrangean relaxation technique to obtain lower and upper bounds. Our computational results have revealed that all solution approaches give satisfactory results in reasonable times.

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Chutima, Parames. "Real-time operational control of flexible manufacturing systems." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283404.

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Darvishi, Alireza. "Philosophy of fixture design for flexible manufacturing systems." Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329682.

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Xu, Dong. "Hardware-based Parallel Simulation of Flexible Manufacturing Systems." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28787.

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This research explores a hardware-based parallel simulation mechanism that can dramatically improve the speed of simulating flexible manufacturing systems (FMS) by applying appropriate enabling hardware technologies. The hardware-based parallel simulation refers to running a simulation on a multi-microprocessor integrated circuit board, called the simulator, which is specifically designed for the purpose of simulating a specific FMS. The board is composed of a collection of micro-emulators capable of mimicking the operation of equipment in FMS such as machining centers, transporters, and load/unload stations. To design possible architectures for the board, a mapping technology is applied by making use of the physical layout information of an FMS. Under such a mapping method, the simulation model is decomposed into a cluster of micro emulator on the board where each workstation is represented by one micro emulator. Three potential architectures for the proposed simulator, namely, the bus-based architecture, the shared-memory based architecture, and the parallel I/O port based architecture, are studied. To provide a suitable parallel computing platform, a prototype simulator based on the combination of the shared-memory and the parallel I/O port architecture is physically built. Besides the development of the hardware simulator, a time scaling simulation method is also developed for execution on the proposed simulator. The method uses the on-board digital clock to synchronize the parallel simulation being performed on different microprocessors. The advantage of the time scaling technology is that the sequence of simulation events is sorted naturally in consistent with the real events. In this way, no entangled waiting is needed as in the conservative parallel simulation methods so as to reduce the synchronization overhead and the danger of having deadlock. Experiments on the prototype simulator show that the time scaling simulation method, combined with the unique hardware features of the FMS specific simulator, achieves a large speedup compared to conventional software-based simulation methods.
Ph. D.

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30

Mohan, Sridhar. "Deadlock avoidance in mixed capacity flexible manufacturing systems." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000428.

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31

Caromicoli, Carl Adam. "Time scale analysis techniques for flexible manufacturing systems." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14705.

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32

Rogers, Paul. "Object-oriented modelling of flexible manufacturing cells." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276540.

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Audsley, Neil C. "Flexible scheduling of hard real-time systems." Thesis, University of York, 1993. http://etheses.whiterose.ac.uk/10925/.

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34

Peters, Brett Avery. "Strategic design of flexible assembly systems." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/24559.

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35

Nair, Girish. "Communications within a computer integrated manufacturing environment." Master's thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-01262010-020049/.

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36

Lee, Siu-lung James. "Hierarchical operational control of automated manufacturing systems /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18812466.

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37

Majette, Mark W. "Modal state variable control of a linear distributed mechanical system modeled with the transfer matrix method." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/15917.

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38

Fu, Ke. "Essays on the management of assemble-to-order systems /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?IELM%202006%20FU.

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39

Fleischman, David R. "A data oriented approach to integrating manufacturing functions in flexible Manufacturing Systems." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/23150.

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Computer Integrated Manufacturing (CIM) seeks to integrate computers into the manufacturing environment, with the end result being a more efficient and productive factory. Current approaches to CIM generally fail to truly integrate the various manufacturing functions (design, scheduling, planning, manufacture, business, etc.) and instead result in self-sufficient, computer- served 'islands of automation.' In these systems, data must be translated before moving from one manufacturing function to another. Wu and Madison have approached data modeling in a CIM environment from a new perspective. Their approach seeks to provide one data model that meets the needs of all manufacturing functions within a factory, negating the need for human or machine data translators. Keywords: Computer integrated manufacturing; Flexible manufacturing systems; Data modeling

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40

Tayanithi, Piyapan. "A new integrated framework for analyzing interruptions in a flexible manufacturing system." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/30997.

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41

Karlsson, Anders. "Developing high performance manufacturing systems." Doctoral thesis, KTH, Production Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3439.

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The work detailed in this dissertation relates to thedevelopment of high performance manufacturing systems. Theperformance factor aimed for is especially flexibility, butthere is an intention of making the results adaptable to focuson performance factors of the readers or users choice. Thefocus of the presented research is not only to provide meansfor accomplishing manufacturing that can handle changes butalso to accomplish flexibility in another area. The resultsshould be applicable in many different situations. The researchhas been divided into three parts: the further development of amanufacturing strategy, the development of a base for amanufacturing system design method and the development of amanufacturing control system.

The developed strategy is called Assembly-InitiatedProduction (AIP). An implementation of the strategy shouldprovide high manufacturing system flexibility but at the sametime contribute to the lowering of inventory levels andlead-times. Different solutions coupled to technicalrequirements found are also discussed.

The design method research focuses on basic manufacturingsystem properties and the possibility of expressing theseproperties by using simple combinable abstract units calledconcepts. The principle is the same as in physics where realworld phenomena may be expressed by using standard concepts asfor example time and mass. The intended use of the results isin an early manufacturing system design phase. The method isnot directly linked to the AIP strategy, but could be used forimplementing it.

Production Planning and Control (PPC) is an important partof a manufacturing system. After having reviewed current PPCpractices, a need for a factory floor PPC system workingregardless of factory floor layout, was identified. Based ontheoretical and industrial studies, the suggested solution is acomputerised, decentralised control system, physicallyseparated from the PPC/ERP system. In order to be able to makequick changes in the schedule, to obtain flexibility and toprovide the organisation with a tool for manufacturing controland decision-making, the system works in real time to provideaccurate and valid data.

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42

Ariffin, Saparudin bin. "Modelling and simulation in support of the design and construction of modular machine control system." Thesis, Loughborough University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336507.

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43

Chen, Chin-Sheng. "Methodologies for manufacturing system selection and for planning and operation of a flexible manufacturing system." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54242.

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A hierarchical methodology is developed for the overall design of manufacturing systems. The methodology consists of solutions to four levels of problems, namely, (1) manufacturing system selection, (2) shop loading, (3) machine loading and tool allocation, and (4) testing the feasibility of a schedule and determining strategies for the operational control of the system. Although these problem levels are developed in a hierarchical sense, they can be applied independently by assuming appropriate inputs to the problem level under consideration. The third and the fourth level problems are addressed in this research for the flexible manufacturing system. The first level of the hierarchical methodology addresses the problem of manufacturing system selection. The mathematical 4 model formulated for this problem captures the basic and integrated relationships among the systems and system components. This model provides a practical approach and a precise tool to determine an optimal mix of systems, to assign appropriate machines to each system, and to select the best material handling system for each system to best suit long-term production requirements at minimum costs. The second level of the hierarchical methodology addresses the shop loading problem. A mathematical model is developed for partitioning parts among the manufacturing systems selected at the first level to minimize total operating costs. For the third level problem, a mathematical model is formulated to obtain routings of parts through an FMS and to assign appropriate cutting tools to each machine in the system to minimize total machining cost. For the fourth level problem, a simulation model is developed for testing the feasibility of the solution obtained at the third level. It also helps to determine strategies for the operational control of the system. The computational experience with the mathematical models is presented using the MPSX-MIP/370 package. Sensitivity analysis is also performed to further understand system behavior under various operating conditions. Several new findings of the research are reported. Because of the special structure of the mathematical models, a computational refinement for their solution is also proposed based on Lagrangian relaxation.
Ph. D.

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44

Jung, Ching-Chuan. "Development of scheduling control system for a flexible manufacturing cell." Thesis, Queensland University of Technology, 1992. https://eprints.qut.edu.au/36109/1/36109_Jung_1992.pdf.

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The dissertation describes the development of the scheduling control system for a flexible manufacturing cell (FMC) established at the School of Mechanical and Manufacturing Engineering, Technology (QUT). The QUT Queensland University of FMC is a two-machine type manufacturing system which consists of a Computer Numerical Controlled (CNC) lathe, a CNC milling machine and an industrial robot which serves both the CNC lathe and the CNC milling machine. To control the constituents of the FMC at a personal computer, a modular tree-type control structure was applied to the scheduling control system. The computer software was written for the scheduling, tool information and job specification aspects of the scheduling control system in "C" language. Two user programs, "CTOOL" and "Crosstalk", were used to control the Robot and the CNC Machine respectively. The system described in this project has the following features: 1 management of job data. 2 execution of the user program which was written in other software language. 3 production of an efficient job schedule and the modification of the schedule. The experimental result indicated that use of scheduling control system with the heuristic algorithm could yielded a reduction in processing time of between 6% and 10% in comparison with a system designed according to the single dispatching rule.

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45

Sarshar, Marjan. "A prototype decision support system for Perturbation Analysis of Flexible Manufacturing Systems." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329755.

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46

Ang, Eu-Jin. "Brownian motion queueing models of communications and manufacturing systems." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298242.

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Bajic, Mirko M. "Design of dynamic cellular manufacturing systems." Title page, abstract and contents only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phb165.pdf.

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Bibliography: leaves 172-184. An analytical approach to the integrated problems of designing the dynamic cellular manufacturing systems layout concurrently with its material flow (handling) requirements, in such a manner that minimises the material handling within the system. The proposed strategy encourages the design of a dynamic layout to identify simultaneously the machine groups, economical machine distribution, and intracell and intercell layouts.

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48

Kilinc, Fatma. "The Tool Transporter Movements Problem In Flexible Manufacturing Systems." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606017/index.pdf.

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In this study, we address job sequencing and tool switching problem arising in Flexible Manufacturing Systems. We consider a single machine with limited tool slots on its tool magazine. The available tool slots cannot accommodate all the tools required by all jobs, therefore tool switches between jobs are required. A single tool transporter with limited capacity is used in transporting the tools from the storage area to the machine. Our aim is to minimize the number of tool transporter movements. We provide two mixed integer linear programming formulations of the problem, one of which is based on the traveling salesman problem. We develop a Branch-and-Bound algorithm powered with various lower and upper bounding techniques for optimal results. In order to obtain good solutions in reasonable times, we propose Beam Search algorithms. Our computational results reveal the satisfactory performance of the B&
B algorithm for moderate sized problems. Moreover, Beam Search techniques perform well for large-sized problems.

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Wang, Junwen. "QUALITY ANALYSIS IN FLEXIBLE MANUFACTURING SYSTEMS WITH BATCH PRODUCTIONS." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/51.

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To improve product quality and reduce cost, batch production is often implemented in many exible manufacturing systems. However, the current literature does not provide any method to analyze the quality performance in a flexible manufacturing system with batch production. In this research, we present an analytical method with closed-form formula to evaluate the quality performance in such systems. Based on the model, we discover and investigate monotonic and non-monotonic properties in quality to provide practical guidance for operation management. To improve product quality, we introduce the notions of quality improvability with respect to product sequencing. In addition, we develop the indicators for quality improvability based on the data available on the factory floor rather than complicated calculations. We define the bottleneck sequence and bottleneck transition as the ones that impede quality in the strongest manner, investigate the sensitivity of quality performance with respect to sequences and transitions, and propose quality bottleneck sequence and transition indicators based on the measured data. Finally, we provide a case study at an automotive paint shop to show how this method is applied to improve paint quality. Moreover, we explore a potential application to reduce energy consumption and atmospheric emissions at automotive paint shops. By selecting appropriate batch and sequence policies, the paint quality can be improved and repaints can be reduced so that less material and energy will be consumed, and less atmospheric emissions will be generated. It is shown that such scheduling and control method can lead to significant energy savings and emission reduction with no extra investment nor changes to existing painting processes. The successful development of such method would open up a new area in manufacturing systems research and contribute to establish a solid foundation for an integrated study on productivity, quality and exibility. In addition, it will provide production engineers and operation managers a quantitative tool for continuous improvement on product quality in flexible manufacturing environment

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Chan, T. S. "Heuristic scheduling algorithms for dedicated and flexible manufacturing systems." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/37964.

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Dissertations / Theses on the topic 'Flexible manufacturing systems'

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