Intelligent Simulation Modeling of a Flexible Manufacturing System with Automated Guided Vehicles

Although simulation is a very flexible and cost effective problem solving technique, it has been traditionally limited to building models which are merely descriptive of the system under study. Relatively new approaches combine improvement heuristics and artificial intelligence with simulation to provide prescriptive power in simulation modeling. This study demonstrates the synergy obtained by bringing together the "learning automata theory" and simulation analysis. Intelligent objects are embedded in the simulation model of a Flexible Manufacturing System (FMS), in which Automated Guided Vehicles (AGVs) serve as the material handling system between four unique workcenters. The objective of the study is to find satisfactory AGV routing patterns along available paths to minimize the mean time spent by different kinds of parts in the system. System parameters such as different part routing and processing time requirements, arrivals distribution, number of palettes, available paths between workcenters, number and speed of AGVs can be defined by the user. The network of learning automata acts as the decision maker driving the simulation, and the FMS model acts as the training environment for the automata network; providing realistic, yet cost-effective and risk-free feedback. Object oriented design and implementation of the simulation model with a process oriented world view, graphical animation and visually interactive simulation (using GUI objects such as windows, menus, dialog boxes; mouse sensitive dynamic automaton trace charts and dynamic graphical statistical monitoring) are other issues dealt with in the study

Applications integration for manufacturing control systems with particular reference to software interoperability issues

The introduction and adoption of contemporary computer aided manufacturing control systems (MCS) can help rationalise and improve the productivity of manufacturing related activities. Such activities include product design, process planning and production management with CAD, CAPP and CAPM. However, they tend to be domain specific and would generally have been designed as stand-alone systems where there is a serious lack of consideration for integration requirements with other manufacturing activities outside the area of immediate concern. As a result, "islands of computerisation" exist which exhibit deficiencies and constraints that inhibit or complicate subsequent interoperation among typical MCS components. As a result of these interoperability constraints, contemporary forms of MCS typically yield sub-optimal benefits and do not promote synergy on an enterprise-wide basis. The move towards more integrated manufacturing systems, which requires advances in software interoperability, is becoming a strategic issue. Here the primary aim is to realise greater functional synergy between software components which span engineering, production and management activities and systems. Hence information of global interest needs to be shared across conventional functional boundaries between enterprise functions. The main thrust of this research study is to derive a new generation of MCS in which software components can "functionally interact" and share common information through accessing distributed data repositories in an efficient, highly flexible and standardised manner. It addresses problems of information fragmentation and the lack of formalism, as well as issues relating to flexibly structuring interactions between threads of functionality embedded within the various components. The emphasis is on the: • definition of generic information models which underpin the sharing of common data among production planning, product design, finite capacity scheduling and cell control systems. • development of an effective framework to manage functional interaction between MCS components, thereby coordinating their combined activities. • "soft" or flexible integration of the MCS activities over an integrating infrastructure in order to (i) help simplify typical integration problems found when using contemporary interconnection methods for applications integration; and (ii) enable their reconfiguration and incremental development. In order to facilitate adaptability in response to changing needs, these systems must also be engineered to enable reconfigurability over their life cycle. Thus within the scope of this research study a new methodology and software toolset have been developed to formally structure and support implementation, run-time and change processes. The tool set combines the use of IDEFO (for activity based or functional modelling), IDEFIX (for entity-attribute relationship modelling), and EXPRESS (for information modelling). This research includes a pragmatic but effective means of dealing with legacyl software, which often may be a vital source of readily available information which supports the operation of the manufacturing enterprise. The pragmatism and medium term relevance of the research study has promoted particular interest and collaboration from software manufacturers and industrial practitioners. Proof of concept studies have been carried out to implement and evaluate the developed mechanisms and software toolset

3D Simulation and Virtual Reality as Methods for Conceptualization, Designing and Visualization of an Automated Lithium-Ion Battery Factory

3D modeling and simulation have proven to be important methods when it comes to manufacturing process planning and conceptualization. With recent development in computer processing capabilities and Virtual Reality (later VR), 3D modelling and simulation methods for prototyping in manufacturing industry has become even more powerful when used together with VR for design optimization, realistic visualization, and information dissemination for everyone. This research is part of a bigger research project at the University of Vaasa that utilized both experimental and case study research strategies to conceptualize an automated lithium-ion battery (later LIB) manufacturing factory simulation model that can be viewed with a VR headset. The VR glasses were used for optimization during modeling and it also helped with information dissemination of the simulation model for non-technical managers. A video of the complete simulation model was produced and a dedicated website that explains different stages of the automated LIB manufacturing factory using pictures and videos from the layout was developed as well. The entire 3D simulation was done with Visual Components software and a complementary VR software called visual experience developed by Visual Components Oy. The results of this research show that 3D simulation together with VR can help any simulation engineer to effectively and quickly optimize simulation models in order to prevent future mistakes in real life projects, thereby reducing lead time and saving money.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Analyzing and improving air cargo terminal operations

Master'sMASTER OF ENGINEERIN

Introduction to Production: Philosophies, Flow, and Analysis

Production is a fundamental societal and economic activity. Production has to do with the transformation of raw materials into useful objects and includes the knowledge to complete the transformation effectively. Thus, production is a board topic ranging from philosophies about how to approach production such as lean and quick response manufacturing, how to organize production facilities, how to analyze production operations, how to control the flow of materials during production, the devices used to move materials within a facility, and strategies for coordinating multiple production facilities. An integrated introduction to production is presented in a set of learning modules. In significant part, these learning modules are based on over 20 years of interactions with the professional production community in the West Michigan region where Grand Rapids and Holland are the principal cities. This community consists almost exclusively of small and medium size companies engaged primarily in high mix, low volume manufacturing. Students in the Bachelor of Science in Engineering and Master of Science in Engineering programs at Grand Valley State University often work in production for these companies. Thus, interactions are facilitated particularly though master’s degree capstone projects, several of which are referenced in the learning modules. The learning modules are well-grounded in established production concepts. Emphasis is placed on proven procedures such as systematic layout planning, factory physics, various production flow control techniques such as kanban and POLCA, and discrete event simulation. Professional practice is a focus of the learning modules. Material from processional groups such as the Lean Enterprise Institute and the Material Handling Institute (MHI) is integrated. The opportunity to read and discuss professional publications presenting production improvement projects is provided. Students are referred to professional videos and web sites throughout the learning modules. All materials provided are referenced are open access and free of charge. When downloading the main file, it is important to also download and use the Main File Support as it contains supplemental materials.https://scholarworks.gvsu.edu/books/1022/thumbnail.jp

Designing a cellular-based fully automated case picking system

Order picking (OP) is the most expensive and labor-intensive activity in warehouses. Some authors argue that OP might be responsible for up to 55% of the operating costs in a warehouse. This might be more important for companies that handle large volumes of fast-moving commodities. Full-case picking processes and mixed pallet building are expensive and complex activities. Companies are looking for technologies to improve their efficiency and to reduce the operating costs of non-value added activities in their warehouses and distribution centers (DCs). Nowadays, the designers of order picking systems face great challenges due to increasing labor costs, less space and more frequent small orders with short delivery times. Consequently, there are constant research efforts devoted to finding new innovative full-case picking solutions that reduce operating costs, generate higher productivity, optimize space utilization and enhance customer service levels. This dissertation presents a new fully automated case picking system (ACPS) called the Automated Cellular Case Picking System (ACCPS). The new system is characterized by the full and permanent accessibility of all stock keeping units (SKUs) in the system, which permits a strategic higher picking rate. This new system could be applied to different levels of automation within warehouses and DCs, and it is suitable for a wide range of warehouse automation requirements. The proposed design consists of storage cells with the same design and operating principle as the vertical indexing case elevator, installed on one conveyor to form a storage line. Several storage lines are connected by a distributing conveyor from the inlet side and by a collecting conveyor from the outlet side, to form an ACCPS use-case model. The concept of this new system is based on the A-Farm concept, in order to create a new innovative dispensing and buffering system for cases. ACCPS is a new concept for a full-case picking system that aims to provide better solutions for warehouses and DCs that deal with a high volume and low variety of products, which are handled in plastic crates or trays. ACCPS would be an efficient solution for many types of commodities such as (food, beverage, grocery, dairy, flowers, sausage, bakery and others). Optimizing picking processes, minimizing operating cost, and increasing efficiency are the most important aims of the new proposed design. This research investigates the layout, design, structure, costs, operating principles, cycle time, and throughput of the new system. A simple logic process was applied to create a mathematical model in order to calculate the expected average time of the order picking and the throughput of this new ACPS. A simulation model has been developed to aid in measuring the effectiveness of the ACCPS proposed design under real operating conditions. Two case studies have been used to evaluate the performance of the new system. Based on the real-time data of these two cases, many simulation scenarios were studied and analyzed in order to solve the storage assignment problem and to determine the best order picking strategy. Many optimization scenarios were simulated and analyzed in order to determine the optimum scenario. In order to evaluate the ACCPS performance, a comparison was made between ACCPS and an alternative system with the same features. The alternative system, which is the most competitive system compared to the ACCPS, is the Gantry Robot System (GRS). The costs, throughput, and required areas were chosen as the main criteria for comparison between the two systems. The comparison confirmed the benefits of the ACCPS in decreasing the operating costs, required area, energy consumption, and the picking time. ACCPS also increased the space utilization rate and the throughput. ACCPS provides a new technique for automating the full-case picking process (CPP) that contributes greatly to decreasing total operating cost by minimizing labor requirements, space requirements, and potential errors, and increasing productivity and efficiency. The structure of ACCPS, which is based on individual modules, can further increase the flexibility and the adaptability of the system.Entwurf eines zellbasierten vollautomatischen Full-Case-Kommissioniersystems Der Kommissionierungsprozess (OP) wird als die höchst arbeitsintensive und kostenaufwändige Tätigkeit in den Lagern betrachtet. Einige Autoren behaupten, dass der Kommissionierungsprozess für bis zu 55 % aller Betriebskosten in einem Lager dafür verantwortlich sein könnte. Dies könnte möglicherweise wichtiger sein für Unternehmen, die große Volumina von schnell bewegenden Waren behandeln. Full-case-picking Prozesse und Mischpaletten von verschiedenen Produkten aufzubauen sind teure und komplexe Tätigkeiten. Firmen suchen nach Technologien, um ihre Leistungsfähigkeit zu verbessern und die Betriebskosten von zusätzlichen Tätigkeiten die keine Wertschöpfung erbringen in ihren Lagern und Distributionszentren (DCs) zu reduzieren. Heutzutage stehen die Designer der Kommissioniersysteme vor großen Herausforderungen, aufgrund der steigenden Arbeitskosten, weniger Platz und häufigere kleine Aufträge mit kurzen Lieferzeiten. Deshalb sind ständige Forschungsbemühungen gewidmet, um die Suche nach neuen innovativen Kommissionierlösungen für Stückgüter, die die Betriebskosten verringern, die Produktivität erhöhen, die Raumausnutzung optimieren und die Kundenservice verbessern. Diese Dissertation präsentiert ein neues vollautomatisiertes Kommissioniersystem für Stückgüter (ACPS), das als automatisiertes zelluläres Case-picking-system (ACCPS) bezeichnet wird. Das neue System zeichnet sich durch die vollständige und dauerhafte Zugänglichkeit aller Lagerhaltung Einheiten (SKUs) im System, das einen strategischen höheren Durchsatz des Kommissionierungsprozesses ermöglicht. Dieses neue System könnte auf verschiedene Niveaus der Automation innerhalb von Lagern und DCs angewandt werden, und ist für eine breite Reihe von Lagerautomationsvoraussetzungen passend. Das vorgeschlagene Design besteht aus Speicherzellen mit demselben Design und Betriebsprinzip wie der vertikale Senkrechtförderer für Stückgüter, der auf einem Förderband installiert ist, um eine Lagerungslinie zu bilden. Mehrere Lagerungslinien werden sich durch einen Verteilförderer von der Einlassseite und durch einen Sammelförderer von der Ausgangsseite verbunden, um ein ACCPS Use-Case-Modell zu bilden. Das Konzept dieses neuen Systems basiert auf dem Konzept des Schachtkommissionsystems (A-Farm), um ein neues innovatives System zum Zuführen und Puffern von Stückgütern zu schaffen. ACCPS ist ein neues Konzept für eine vollständiges Stückgütern Schachtkommissionsystem mit dem Ziel, bessere Lösungen für Lagern und DCs, die sich mit einer großen Menge und niedrigen Vielfalt von Produkten befassen, die in Kunststoffkisten oder Tablare behandelt werden zur Verfügung zu stellen. ACCPS würde eine effiziente Lösung für viele Typen von Waren wie (Nahrung, Getränk, Lebensmittel, Molkerei, Blumen, Wurst, Bäckerei und andere) sein. Optimierung der Kommissionierungsprozesse, Minimierung der Betriebskosten und Steigerung der Effizienz sind die wichtigsten Ziele des neuen vorgeschlagenen Designs. Diese Forschung untersucht Layout, Design, Struktur, Kosten, Betriebsprinzipien, Zykluszeit und Durchsatz des neuen Systems. Ein einfacher Logik-Prozess wurde angewendet, um ein mathematisches Modell zu erstellen, damit die erwartete durchschnittliche Zeit der Kommissionierung und der Durchsatz von dieser neuen ACPS zu berechnet werden. Ein Simulationsmodell wurde entwickelt, um bei der Messung der Effektivität des vorgeschlagenen Designs der ACCPS unter realen Betriebsbedingungen zu unterstützen. Zwei Fallstudien sind verwendet worden, um die Leistung des neuen Systems zu bewerten. Gestützt auf den Echtzeitdaten dieser zwei Fälle, viele Simulation Szenarien wurden untersucht und analysiert um das Problem der Lagerplatzzuweisung zu beheben und die beste Strategie für die Kommissionierung zu bestimmen. Viele Optimierung Szenarien wurden simuliert und analysiert um das optimale Szenario zu bestimmen. Im Hinblick auf die Bewertung der Leistung des ACCPSs, wurde ein Vergleich zwischen ACCPS und ein alternatives System mit denselben Eigenschaften durchgeführt. Das Gantry Robot System (GRS), ist das alternative System für das am meist konkurrenzfähige System im Vergleich zum ACCPS. Die Kosten, der Durchsatz und die erforderliche Fläche wurden als die Hauptkriterien zum Vergleich zwischen den beiden Systemen gewählt. Der Vergleich hat die Vorteile des ACCPSs im Verringern der Betriebskosten, der erforderlichen Fläche, des Energieverbrauchs und der Entnahmezeit (Pickzeit) bestätigt. ACCPS stellt eine neue Technik zur Verfügung, um die Full-case-picking Prozessen (CPP) zu automatisieren, die außerordentlich zum Verringern von Gesamtbetriebskosten durch die Minderung von Arbeitskräftebedarf, Platzbedarf und potenziellen Fehlern, und die Erhöhung der Produktivität und Leistungsfähigkeit beiträgt. Die Struktur von ACCPS, die auf individuellen Modulen basiert, kann weiter die Flexibilität und die Anpassungsfähigkeit des Systems vergrößern

Methodology to develop hybrid simulation/emulation model.

Trends towards reduced life-time of products and globalised competition has increased pressure on manufacturing industries to be more responsive to changing needs of product markets. Consequently, the use of simulation to describe short term future performance of manufacturing system has become more significant than ever. An application of simulation that has attracted attention is for testing of control logic before commissioning on site by using a detailed simulation model called emulation model. However, though the success of using emulation particularly in improving cost-effectiveness of automated material handling system delivery has been acknowledged by industries and simulation model developers, the uptake for this technology is still low. The major inhibitors are the high costs of its model building as well as simulation and emulation models are perceived to be non convertible.The main objective, of this research is to establish a methodology to develop simulation model that can be converted into emulation model with ease, thus making emulation technology more affordable. The product of this research called the methodology to build Hybrid Simulation Emulation Model (HSEM) is a new approach of building emulation model comprising of three phases namely (1) development of base simulation model, (2) development of detail emulation model, and (3) integration of controller with the emulation model. Important requirements for HSEM are flexibility of adding details to the simulation model and inter process communication between model and real control system. To facilitate implementation of the methodology, it is essential that the simulation software package provide functionalities for modular model development, access and adding of codes, integration with other application and real time (RT) modelling.The methodology developed offers a more affordable emulation modelling and an opening for further research into the comprehensive support for the implementation of real time control system testing using emulation