No / A Reconfigurable Manufacturing System (RMS) is a new paradigm that focuses on manufacturing a high variety of products at the same system. Having specified a design strategy for an RMS as the first design step at the tactical level, products must be grouped to identify and allocate corresponding manufacturing facilities. An interface between market and manufacturing called reconfiguration link is presented to specify and arrange products for manufacturing. The reconfiguration link incorporates the tasks of determining the products in the production range, grouping them into families and selecting the appropriate family at each configuration stage. The proposed approach of (re)configuring products before manufacturing facilitates assigning product families to the required manufacturing facilities in terms of (re)configuring manufacturing systems. This paper contributes an overall approach of grouping products into families based on operational similarities, when machines are still not identified. Since the problem of product family selection consists of quantitative and qualitative objectives, the Analytical Hierarchical Process (AHP) is then used while considering both market and manufacturing requirements. The AHP model is verified in an industrial case study through using Expert Choice software. The solutions take advantage of monitoring sensitivity analysis while changing the priorities of manufacturing and/or market criteria. The concept of the proposed model is generic in structure and applicable to many firms. However, the model must be adapted according to the specific nature of the company under study. For instance, product family choices may differ from one company to another because of the available technology and the volume and type of existing products in the production range.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This thesis considers the evaluation of LabVIEW based control for reconfigurable manufacturing systems (RMSs), and in particular for an RMS subsystem. The evaluation used a rivet feeder station as a case study. The architecture of the rivet feeder station included a vibratory bowl feeder, a singulation device, a pick-n-place mechanism and an XYZ positioning table. The objective of the research was to determine whether LabVIEW is a suitable development environment for implementing holonic control. The motivation for considering LabVIEW in this thesis was that other control approaches, such as IEC 61499 function blocks, agent-based control and object-orientated control, that have been used in most RMS research, have not found favour with industry. The PROSA holonic reference architecture was adopted here, with the following holons: Coms Holon, Request Manager Holon, Order Holon, Product Holon Manager, Pick-n-Place Holon and XYZ Table Holon. The holons, constituting the controller, were designed based on LabVIEW’s producer/consumer and state machine architectures. The controller was aimed at making the rivet feeder station reconfigurable. Furthermore, the controller was interfaced with a cell controller through a TCP/IP connection and an XML format of messaging was adopted for communication. The main limitations and disadvantages of LabVIEW, for the implementation of holonic control systems, were found to be: the graphical programming which makes the block diagram cumbersome to follow, for complex applications; and that dynamic instantiation of objects or memory cannot be achieved in LabVIEW. However, LabVIEW holds the following advantages: shared variables and TCP/IP components simplify communication over a network; easy construction of the graphical user interface using controls and indicators on LabVIEW front panels; the XML standard format in LabVIEW provides flexibility to create your own unlimited tags; and immediate compilation of LabVIEW programs. Furthermore, LabVIEW easily can be integrated with hardware such as the compactRIO with a CANopen card. The reconfigurability assessment of the rivet feeder station included three experiments which involved changing the product type, adding new devices and performing station diagnostics. From these experiments, it was concluded that the key characteristics of reconfigurable manufacturing systems were achieved, thereby demonstrating the suitability of LabVIEW for implementing holonic control. / AFRIKAANSE OPSOMMING: Hierdie tesis beskou die evaluering van LabVIEW-gebaseerde beheer vir herkonfigureerbare vervaardigingstelsels (RMSs), en in besonder vir 'n RMS substelsel. Die evaluering het 'n klinknaelvoerstasie as gevallestudie gebruik. Die voerstasie se argitektuur het 'n vibrerende bakvoerder, 'n singuleringstoestel, 'n optel-en-plaas-robot en 'n XYZ-posisioneringstafel ingesluit. Die doelwit van die navorsing was om te bepaal of LabVIEW 'n geskikte ontwikkelingsomgewing vir die implementering van holoniese beheer bied. Die motivering vir die oorweging van LabVIEW in hierdie tesis was dat ander beheerbenaderings, soos IEC 61499 funksieblokke, agent-gebaseerde beheer and objek-georiënteerde beheer, wat in die meeste RMS-navorsing gebruik is, nie aanvaarding in die nywerheid gevind het nie. Die PROSA holoniese verwysingsargitektuur is hier gebruik, met die volgende holone: Coms Holon (kommunikasieholon), Request Manager Holon (versoekbestuurholon), Order Holon (bestellingholon), Product Holon Manager (produkholonbestuurder), Pick-n-Place Holon (optel-en-plaasholon) en XYZ Table Holon (XYZ-tafelholon). Die holone, wat die beheerder uitmaak, se ontwerp is gebou op LabVIEW se vervaardiger/verbruiker- (producer/consumer) en toetstandmasjien-argitekture. Die beheerder was daarop gemik om die klinknaelvoerstasie herkonfigureerbaar te maak. Verder, die beheerder het 'n koppelvlak met 'n selbeheerder gehad, waarin 'n TCP/IP-verbinding en 'n XML-formaat vir die kommunikasie-boodskappe gebruik is. Die belangrikste beperkings en nadele van LabVIEW, vir die implementering van holoniese beheerstelsels, het geblyk te wees: die grafiese programmering wat die blokdiagramme moeilik maak om te volg, vir komplekse toepassings; en dat objekte en geheue nie in LabVIEW dinamies geskep kan word nie. LabVIEW het, egter, die volgende voordele: gedeelde veranderlikes en TCP/IP-komponente vereenvoudig netwerkkommunikasie; gerieflike skepping van die grafiese gebruikerskoppelvlak met behulp van beheerders en meters (controls and indicators) op LabVIEW se voorpanele (front panels); die XML-standaard-formaat in LabVIEW voorsien buigsaamheid om jou eie onbeperkte etikette (tags) te skep; en onmiddellike vertaling van LabVIEW programme. Verder, LabVIEW kan maklik geïntegreer word met hardeware soos die "compactRIO" met 'n "CANopen" kaart. Die beoordeling van die herkonfigureerbaarheid van die klinknaelvoerstasie het drie eksperimente ingeluit waarin die verandering van die produktipe, die byvoeging van nuwe toestelle en die uitvoering van stasie-diagnoses betrokke was. Uit hierdie eksperimente kan afgelei word dat die sleutel-eienskappe van herkonfigureerbare vervaardigingstelsels behaal is, waardeur aangetoon is dat LabVIEW geskik is om holoniese beheer te implementeer.

Manufacturing companies today face increasingly uncertain and volatile market demands. Product designs and the required quantities change rapidly to meet the needs of customers. To maintain competitiveness in this uncertain environment, manufacturing companies need to possess agility to dynamically and effectively adapt to the changing environment. Agility at the machine level can be thought of as the ability to reconfigure manufacturing machines in response to changing needs and opportunities. This thesis is concerned with a design method for machine level agility for reconfigurable manufacturing machines. This thesis is divided into two portions: a design approach for reconfigurable manufacturing machines and the embodiment of this approach in a computational synthesis example. In developing this design method, various approaches and reconfigurable systems are presented to develop an overview of the applications and current related research to reconfigurable manufacturing machines. From this related research, a research gap is identified pertaining to the identification of the evolving architecture of reconfigurable manufacturing machines. The key contribution is the design approach based on co-evolution. This design approach involves the implementation of agent based co-evolutionary algorithms. In this implementation, each agent synthesizes the configuration of a machine for a product in the range of products it is to manufacture and co-evolves with other agents which are synthesizing machines for other products to reduce the reconfiguration cost. Finally, an in-depth case study of the design approach is presented in which the approach is tested relative to various product changes; thus, showing the advantages of employing an evolving reconfigurable machine architecture. These product changes include batch size variations, geometry changes, and material changes. Hence, the core objective is to identify the necessary reconfigurable manufacturing machine architecture for the range of configurations required for machining various products.

No / This paper presents Reconfigurable Manufacturing System (RMS) characteristics through comparison with conventional manufacturing systems in order to address a design strategy towards a RMS. The strategy is considered as apart of a RMS design loop to achieve a reconfigurable strategy over its implementation period. As another part of the design loop, a reconfiguration link between market and manufacturing is presented in order to group products into families (reconfiguring products) and then assign them to the required manufacturing processes over configuration stages. In particular, the Analytical Hierarchical Process (AHP) is employed for structuring the decision making process for the selection of a manufacturing system among feasible alternatives based on the RMS study. Manufacturing responsiveness is considered as the ability of using existing resources to reflect new environmental and technological changes quickly. The AHP model highlights manufacturing responsiveness as a new economic objective along with classical objectives such as low cost and high quality. The forward-backward process is then proposed to direct and control the design strategy under uncertain conditions during its implementation period. The proposed hierarchy is generic in structure and could be applicable to many firms by means of restructuring the criteria. This work is based on a case study in a manufacturing environment. Expert Choice software (Expert Choice 1999) is applied to examine the structure of the proposed model and achieve synthesise/ graphical results considering inconsistency ratios. The results are examined by monitoring sensitivity analysis while changing the criteria priorities. Finally, to allocate available resources to the alternative solutions, a (0-1) knapsack formulation algorithm is represented.

Purpose – To achieve high reconfigurability in a manufacturing system, six characteristics need to be implemented, where each characteristic contributes to different benefits when implemented. How these benefits are influenced by a volume reduction is not investigated in the literature. Therefore, the study aims to investigate how volume reduction affects the benefits of reconfigurable manufacturing systems (RMS). Method – The study is a qualitative single case study with quantitative features. The case company selected is a Swedish automotive company and the unit of analysis was the benefits of RMS. Two similar RMS with different capacity levels at the case company were compared to achieve the purpose of the study. The data was collected through interviews at the case company, as well as through a document study containing data collected by the case company. Findings – The findings showed that the throughput time was decreased in a volume reduction context due to the decreased production capacity. However, the quality was improved in a volume reduction context by 19%. The case company is scalable with the people in the system before evaluating the need to remove machines from it to decrease the capacity. Moreover, benefits related to social sustainability were identified in the data collected, where the stress level of operators was improved in a volume reduction context. Implications – Scalability enables easy and rapid capacity reduction in a manufacturing system, however, scaling with people is easier than removing machines physically. There is a lack of focus on social sustainability and the human system in RMS literature, thus, it needs to be further investigated. There are RMS benefits not influenced by a volume reduction, and even if the quality was improved in a volume reduction context, it is unclear if the RMS characteristic or other factors influenced it. Limitations – The single case study was carried out in retrospect. Therefore, finding interviewees at the company that could recall information was a challenge. Most of the literature found on RMS benefits is related to the same author, which may have affected the credibility.

The Plug & Produce manufacturing system is a visionary concept that promises to facilitate the seamless integration and adaptation of manufacturing resources and production processes. The Plug & Produce control system allows for the automatic addition and removal of manufacturing resources, minimizing human intervention. However, the reconfigurability and autonomous decision-making features of Plug & Produce control systems pose challenges to safety design and control functions. In contrast to conventional manufacturing systems with fixed layouts and processes, ensuring safety in Plug & Produce systems is complicated due to the complex risk assessment process, the difficulty of implementing non-restrictive safety measures covering all possible hazards, and the challenge of designing a reliable controller for consistent safe operation. This thesis addresses these challenges through various contributions. It introduces an automatic hazard identification method, considering emergent hazards after reconfiguration. A novel domain ontology is developed, incorporating safety models specific to Plug & Produce systems. The work also proposes a generic, model-based, and automatic risk assessment method, along with a method for the safe execution of plans based on the results of the risk assessment. The results of this research offer benefits to process planners, who are responsible for coordinating the manufacturing processes with product design in the Plug & Produce system. The proposed solution provides tools for process planners to validate their plans and reduces their safety-related responsibilities. The proposed safety assurance method seamlessly integrates into the multi-agent control of Plug & Produce, providing the control system with risk scenarios associated with process plans. This enables proactive and reliable control, effectively avoiding potential risks during system operation. / Föreställ dig en automatiserad produktionsanläggning som omedelbart och automatiskt kan anpassa sig till förändringar utan att kompromissa med säkerheten för den personal som arbetar där. Denna avhandling strävar efter att uppnå just detta genom ett smartare sätt att säkerställa att produktionsanläggningar baserat på Plug & Produce kan hantera säkerhet. Dettainnebär att konceptet Plug & Produce nu närmar sig ett industriellt förverkligande. Säkerhet för automatiserade produktionsanläggningar innebär att alla maskiner ska vara utrustade med skydd för att göra arbetet säkrare. Idag är det vanligt med övervakning som skydd, dvs en dator som övervakar att allt går rätt till och stänger av om något är på väg att hända. I ett produktionsavsnitt som är baserat på Plug & Produce kan man enkelt ställa om, det vill säga, lägga till eller ta bort maskiner, ändra layouten eller ändra på produkter som produceras. Efter en sådan omställning så måste säkerheten i produktionsanläggningen ses över enligt föreskrivna lagar och regler. Traditionellt så kräver detta anlitande av en säkerhetsexpert. Detta medför att en omställning utifrån ett säkerhetsperspektiv är både kostsamt och tidskrävande. Med resultatet från denna avhandling så går det nu att ställa om utan att behöva implementera nya säkerhetsfunktioner efter varje förändring. Denna forskning har utvidgat kunskapsområdet inom produktionsteknik för att skapa en "smartarefabrik" genom att inkludera säkerhetsfunktioner.Resultatet inkluderar algoritmer som kan upptäcka potentiella faror i fabriken och automatiskt tillämpa säkerhetsåtgärder för ett övervakat system. Detta innebär mindre tidsåtgång och lägre kostnader för säkerhetsarbetet. De som drar mest nytta av detta är människorna som planerar för hur saker skall tillverkas med hjälp av Plug & Produce. Resultatet av detta arbete underlättar deras arbetsuppgifter och bevarar flexibiliteten i Plug & Produce, vilket eliminerar behovet av att välja mellan flexibilitet och säkerhet

No / Reconfigurable manufacturing systems (RMSs) are designed based on the current and future requirements of the market and the manufacturing system (MS). The first stage of designing an RMS at the tactical level is the evaluation of economic and manufacturing/operational feasibility. Because of risk and uncertainty in an RMS environment, this major task must be performed precisely before investment in the detailed design. The present paper highlights the importance of manufacturing capacity and functionality for the feasibility of an RMS design during reconfiguration processes. Due to uncertain demands of product families, the RMS key-design factors, i.e. capacity value, functionality degree and reconfiguration time, are characterized by the identified fuzzy sets. Consequently, an integrated structure of the analytical hierarchical process and fuzzy set theory is presented. The proposed model provides additional insights into a feasibility study of an RMS design by considering both technical and economical aspects. The fuzzy analytical hierarchical process model is examined in an industrial case study by means of Expert Choice software. Finally, the fuzzy multicriteria model is sensitively analysed within the fuzzy domains of those attributes, which are considered to be critical for the case study.

The present dynamic manufacturing environment has been characterized by a greater variety of products, shorter life-cycles of products and rapid introduction of new technologies, etc. Recently, a new manufacturing paradigm, i.e. Reconfigurable Manufacturing Systems (RMS), has emerged to address such challenging issues. RMSs are able to adapt themselves to new business conditions timely and economically with a modular design of hardware/software system. Although a lot of research has been conducted in areas related to RMS, very few studies on system-level control for RMS have been reported in literature. However, the rigidity of current manufacturing systems is mainly from their monolithic design of control systems. Some new developments in Information Technology (IT) bring new opportunities to overcome the inflexibility that shadowed control systems for years. Component-based software development gains its popularity in 1990's. However, some well-known drawbacks, such as complexity and poor real-time features counteract its advantages in developing reconfigurable control system. New emerging Extensible Markup Language (XML) and Web Services, which are based on non-proprietary format, can eliminate the interoperability problems that traditional software technologies are incompetent to accomplish. Another new development in IT that affects the manufacturing sector is the advent of agent technology. The characteristics of agent-based systems include autonomous, cooperative, extendible nature that can be advantageous in different shop floor activities. This dissertation presents an innovative control architecture, entitled Component-based Intelligent Control Architecture (CICA), designed for system-level control of RMS. Software components and open-standard integration technologies together are able to provide a reconfigurable software structure, whereas agent-based paradigm can add the reconfigurability into the control logic of CICA. Since an agent-based system cannot guarantee the best global performance, agents in the reference architecture are used to be exception handlers. Some widely neglected problems associated with agent-based system such as communication load and local interest conflicts are also studied. The experimental results reveal the advantage of new agent-based decision making system over the existing methodologies. The proposed control system provides the reconfigurability that lacks in current manufacturing control systems. The CICA control architecture is promising to bring the flexibility in manufacturing systems based on experimental tests performed. / Ph. D.

Today’s global market and growing competition set an increasing strain to manufacturing companies. Shorter product lifecycles automatically lead to shorter production ramp up periods and, therefore, set a higher strain on the manufacturing systems. The concept of reconfigurable manufacturing systems (RMS) was developed in the early 1990s and has now gained more interest than ever. An RMS is designed to quickly respond to changes in market demand, by adapting its functionality as well as its capacity to the current market requirements. In order to achieve this, an RMS is characterised by six core characteristics: modularity, integrability, diagnosability, convertibility, scalability and customisation. By complying with these characteristics, the manufacturing system can meet the required responsiveness to functionality and capacity changes. Academia has been focusing on the development and design of new RMSs, however, there is a lack in research on converting existing manufacturing systems towards reconfigurability. Additionally, few models assessing a manufacturing system’s current state in terms of reconfigurability are available in literature. The existing reconfigurability assessment models were proven to be rather theoretical and difficult to use by practitioners in industry. Therefore, the need for a reconfigurability assessment model applicable in industry arose. This study focuses on the analysis of enablers of a reconfigurability manufacturing systems as well as on assessing the reconfigurability of an existing manufacturing system in an industrial setting. For this purpose, a detailed reconfigurability assessment model has been developed, based on literature studies and a case study at a case company. A focus of the development of the model has been set on usability in industry. The outcome was an assessment model developed in Microsoft Excel that gives an overview on the reconfigurability of each characteristic as well as the manufacturing system’s overall reconfigurability. The model was subsequently tested and verified at the case company. The final reconfigurability assessment model is presented and explained at the end of this study. This study shows, that through the use of theory about RMS and input from industry it was possible to develop a current state assessment model regarding reconfigurability. To make the model generalisable and adaptable to different industrial settings, further testing in different manufacturing fields and research within RMS is required. / CARV

To compete, manufacturing companies need production systems that quickly can respond to changes. To handle change drivers such as volume variations or new product variants, reconfigurability is advocated as a competitive means. This implies an ability to add, remove, and/or rearrange the structure of the production system to be ready for future changes. Still, it is not clear how the production system design process can capture and support the design of reconfigurable production systems. Therefore, the objective of this thesis is to increase the knowledge of how to support the design of reconfigurable production systems. Reconfigurability could be defined by a number of reconfigurability characteristics including convertibility, scalability, automatibility, mobility, modularity, integrability, and diagnosability. In eight case studies, reconfigurability characteristics in production system design were studied in order to investigate reconfigurability needs, knowledge, and practice in manufacturing companies. In three of the case studies reconfigurable production systems were studied to identify the links between change drivers and reconfigurability characteristics. In the remaining five case studies, reconfigurability in the production system design processes was addressed in terms of needs, prerequisites, and consideration. Based on the literature review and the case studies, support for reconfigurable production system design is suggested including two parts. The first part comprises support for analyzing the need for reconfigurability. Based on relevant change drivers the need for reconfigurability must be identified to enable selection of right type and degree of reconfigurability for each specific case of application. A comprehensive view of the reconfigurability characteristics is presented and links between change drivers and reconfigurability characteristics are described. The characteristics are divided into critical characteristics, that lead to a capacity or functionality change of the production system, and supporting characteristics, that reduce system reconfiguration time but do not necessarily lead to a modification of functionality or capacity of the production system. The second part provides support in how to consider reconfigurability in the production system design process. A holistic perspective is crucial to design reconfigurable production systems and therefore constituent parts of a production system are described. According to their character physical, logical, and human reconfiguration must be considered through the whole production system design process.