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  • 1501.
    Vujicic, Sanja
    et al.
    Univ Gothenburg, Ctr Tourism, Sch Business Econ & Law, Gothenburg, Sweden .
    Wickelgren, Mikael
    University of Skövde, School of Technology and Society.
    Destination Branding in Relation to Airports: The Case of the City of Valencia2011In: European Journal of Transport and Infrastructure Research, ISSN 1567-7133, E-ISSN 1567-7141, Vol. 11, no 3, p. 334-345Article in journal (Refereed)
    Abstract [en]

    This study investigates various factors that contribute to the success of destination branding efforts where success is defined as the increase in airplane passenger numbers to a destination and its linked air transportation. Drawing on in-depth interviews and snowball sampling, the study examines the roles of many of the key actors involved in the efforts to increase passenger numbers. Using the City of Valencia in Spain as a case study, the role of its airport is examined as a factor of particular interest. The study concludes that Valencia has positioned itself among neighbouring destinations on the Spanish Mediterranean coast by its focus on high profile events and cultural tourism. However, other actors have taken a more active role in the effort to increase the number of tourists than the Valencia Airport that has taken a more passive role. Another finding is that the persistence in seeking resources for the costly branding efforts was another influential factor that explains the increase in Valencia tourism.

  • 1502.
    Vuoluterä, Fredrik
    et al.
    University of Skövde, School of Engineering Science.
    Carlén, Oliver
    University of Skövde, School of Engineering Science.
    Analysis of material flow and simulation-based optimization of transportation system: The combination of simulation and Lean to evaluate and design a transportation system2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis has been performed in cooperation with a Swedish manufacturing company. The manufacturing site of the company is currently implementing a new machine layout in one of its workshops. The new layout will increase the product flow to another workshop on the site. The goal of the thesis was to evaluate the current transportation system and suggest viable alternatives for the future product flow. By means of discrete event simulation these alternative solutions would be modelled and subsequently optimized to determine if their performance is satisfactory. An approximated investment cost of the solutions would also be estimated.

    By performing a literature review and creating a frame of reference, a set of relevant methodologies were selected to provide a foundation to the project. Following these methodologies, the current state of transportation was identified and mapped using Value Stream Mapping. Necessary data from the current flow was identified and collected from the company computer systems. This data was deemed partly inaccurate and further verification was needed. To this end, a combination of Genchi Genbutsu, assistance from onsite engineers and a time study was used to verify the unreliable data points. The data sets from the time study and the company data which was deemed valid were represented by statistical distributions to provide input for the simulation models.

    Two possible solutions were picked for evaluation, an automated guided vehicle system and a tow train system. With the help of onsite personnel, a Kaizen Event was performed in which new possible routing for the future flow was evaluated. A set of simulation models portraying the automated guided vehicle system and the tow train system were developed with the aid of simulation software. The results from these models showed a low utilization of both systems. A new set of models were developed, which included all the product flows between the workshops. The new flows were modelled as generic pallets with the arrival distribution based on historical production data. This set of models were then subject for optimization with regard to the work in process and lead time of the system. The results from the optimization indicates the possibility to reduce the overall work in process by reducing certain buffer sizes while still maintaining the required throughput. These solutions were not deemed to be ready for implementation due to the low utilization of the transportation systems. The authors instead recommend expanding the scope of the system and including other product flows to reach a high utilization.

  • 1503.
    Wahlström, Ole
    University of Skövde, School of Informatics.
    Valörers betydelse i spel: En studie om att upptäcka föremål2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Studiens fokus var att undersöka hur olika nivåer av valörer, påverkar tiden det tar att upptäcka objekt i spel. Områden som hur kontraster och immersion kan påverka detta tas upp, likaså hur affordance påverkar hur lätt en spelare anpassar sig efter de förutsättningar som ett spel erbjuder. En spelbar mod skapades för att undersöka om korrigerade valörer på några modifierade vapen kunde visa på några tendenser i hur lång tid olika valörer tar att upptäcka. Den tid det tog varje informant att hitta sagda vapen, jämfördes med den totala tid som varje vapen fanns på skärmen innan upptäckt. Resultatet pekade sedan mot att ljusare valörer gjorde det lättare att upptäcka objekt, medan mörkare valörer gjorde det svårare. Ett fortsatt framtida arbete skulle gynnas av fler informanter och fler spelmiljöer för att få ett mer trovärdigt resultat.

  • 1504.
    Walander, Tomas
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Cohesive modelling of the temperature dependence of epoxy based adhesives in Mode I and Mode II loading2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this work, the influence of the temperature on the cohesive laws for two epoxy adhesives is studied at temperatures below the glass transition temperature for both Mode I and Mode II loading. Cohesive laws are measured experimentally under quasi-static loading conditions in the temperature range -30≤T≤80"C" . Three parameters of the cohesive laws are studied in detail: the elastic stiffness, the peak stress and the fracture energy. Methods for determining the elastic stiffness in Mode I and Mode II are derived and evaluated. With these methods, the results in this work show that it is possible to measure all three parameters for each pure mode loading case by the use of only the DCB- and the ENF-test specimens. Even though the measures tend to spread in values, this can significantly reduce the cost for performing experiments. It is shown that most of the cohesive parameters are decreasing with an increasing temperature in both loading modes and for both adhesives. An exception is the Mode I fracture energy for one of the adhesives. This is shown to be independent of the temperature in the studied temperature range. For the same adhesive, the Mode II fracture energy is shown to be continuously decreasing with an increasing temperature. The experimental results are verified by finite element analyses. The simulations only consider uncoupled cohesive behaviours. By use of the experimental results, simplified bi-linear cohesive laws to be used at any temperature within the studied temperature range are derived for one adhesive in both loading modes. This is desired in order to simulate adhesively bonded structures that suffer a wide range in temperature.

  • 1505.
    Walander, Tomas
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Chalmers University of Technology.
    Influences of temperature, fatigue and mixed mode loading on the cohesive properties of adhesive layers2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis concerns some aspects that have influence on the strength of adhesive layers. The strength is determined by the stress deformation-relation of the layer. This relation is also referred to as cohesive law. The aspects having influence on the cohesive laws that are studied in this work are temperature, fatigue, multi-axial fatigue and mixed mode loading.

    For each aspect, a model is developed that can be used to describe the influence of the aspects on the cohesive laws numerically, e.g. by using the finite element method. These models are shown to give good agreement with the experimental results when performing simulations that aims at reproducing the experiments. For the aspect of temperature, a FE-model is suggested that can be used to simulate the mechanical behaviour in pure mode loadings at any temperature within the evaluated temperature span. Also, a damage law for modelling high cycle fatigue in a bonded structure in multi-axial loading is presented. Lastly, a new experimental set-up is presented for evaluating strength of adhesives during mixed mode loading. The set-up enables loading with a constant mode-mix ratio and by the experimental results, a potential model for describing the mechanical behaviour of the evaluated adhesive is presented.

  • 1506.
    Walander, Tomas
    University of Skövde, School of Technology and Society.
    System for measurement of cohesive laws2009Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In this thesis an experimental method to calculate cohesive characteristics for an adhesive layer in a End Notched Flexure (ENF) specimen is presented and evaluated. The method is based on the path independent J-integral where the energy release rate (ERR) for the adhesive is derived as a function of the applied forces and the rotational displacements at the loading point and at the supports of the specimen. The major advantage with the method in comparison with existing theory known by the job initiator is that it is still applicable with ENF specimens that are subjected to yielding of the adherends.

    The structure of this thesis is disposed so that the theory behind the J-integral method is shortly described and then an evaluation of the method is performed by aid of finite element simulations using beam and cohesive elements. The finite element simulations indicates that the ERR can be determined with good accuracy for an ENF specimen where a small scale yielding of the adherends has occurred. However when a fully cross sectional yielding of the adherends is reached the ERR starts diverging from the exact value and generates a too high ERR according to input data in the simulations, i.e. the exact values. The importance in length of the adhesive process zone is also shown to be irrelevant to the ERR measured according to the J-integral method.

    Simulation performed with continuum elements indicates that a more reality based FE- simulation implies a higher value of the applied load in order to create crack propagation. This is an effect of that the specimen is allowed to roll on the supports which makes the effective length between the supports shorter than the initial value when the specimen is deformed. This results in a stiffer specimen and thus a higher applied force is needed to create crack propagation in the adhesive layer.

    An experimental set up of an ENF specimen is created and the sample data from the experiments are evaluated with the J-integral method. For measuring the rotational displacements of the specimen which are needed for the J-integral equation an image system is developed by the author and validated by use of linear elastic beam theory. The system calculates the three rotational displacements of the specimen by aid of images taken by a high resolution SLR camera and the system for measuring the rotations may also be used in other applications than for a specific ENF geometry. The validation of the image system shows that the rotations calculated by the image system diverge from beam theory with less than 2.2 % which is a quite good accuracy in comparison with the accuracies for the rest of the used surveying equipment.

    The results from the experiment indicates that the used, about 0.36 mm thick SikaPower 498, adhesive has an maximum shear strength of 37.3 MPa and a critical shear deformation of 482 µm. The fracture energy is for this thickness of the adhesive is determined as 12.9 kJ/m2.

    This report ends with a conclusion- and a suggested future work- chapter.

  • 1507.
    Walander, Tomas
    et al.
    University of Skövde, School of Technology and Society.
    Biel, Anders
    University of Skövde, School of Technology and Society.
    Stigh, Ulf
    University of Skövde, School of Technology and Society.
    An evaluation of the temperature dependence of cohesive properties for two structural epoxy adhesives2012In: 19th European Conference on Fracture, Kazan Scientific Centre of the Russian Academy of Sciences , 2012Conference paper (Refereed)
    Abstract [en]

    Cohesive modelling provides a more detailed understanding of the fracture properties of adhesivejoints than provided by linear elastic fracture mechanics. A cohesive model is characterized by astress-deformation relation of the adhesive layer. This relation can be measured experimentally.Two parameters of the stress-deformation relation are of special importance; the area under thecurve, which equals the fracture energy, and the peak stress. The influence of temperature of theseparameters is analyses experimentally and evaluated statistically for two structural epoxy adhesivesin the span from of -40°C to +80°C. The adhesives are used by the automotive industry and atemperature span below the glass transition temperature is considered. The results show that thattemperature has a modest influence on the adhesives Mode I fracture energy. For one of theadhesives, the fracture energy is independent of the temperature in the evaluated temperature span.In mode II, the influence of temperature is larger. The peak stresses decreases almost linearly withan increasing temperature in both loading cases and for both adhesives.

  • 1508.
    Walander, Tomas
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Biel, Anders
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Stigh, Ulf
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Temperature dependence of cohesive laws for an epoxy adhesive in Mode I and Mode II loading2013In: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 183, no 2, p. 203-221Article in journal (Refereed)
    Abstract [en]

    The influence of the temperature on the cohesive laws for an epoxy adhesive is studied in the glassy region, i.e. below the glass transition temperature. Cohesive laws are derived in both Mode I and Mode II under quasi-static loading conditions in the temperature range C. Three parameters of the cohesive laws are studied in detail: the elastic stiffness, the peak stress and the fracture energy. Methods for determining the elastic stiffness in Mode I and Mode II are derived and evaluated. Simplified bi-linear cohesive laws to be used at any temperature within the studied temperature range are derived for each loading mode. All parameters of the cohesive laws are measured experimentally using only two types of specimens. The adhesive has a nominal layer thickness of 0.3 mm and the crack tip opening displacement is measured over the adhesive thickness. The derived cohesive laws thus represent the entire adhesive layer as having the present layer thickness. It is shown that all parameters, except the Mode I fracture energy, decrease with an increasing temperature in both loading modes. The Mode I fracture energy is shown to be independent of the temperature within the evaluated temperature span. At C the Mode II fracture energy is decreased to about 2/3 of the fracture energy at C. The experimental results are verified by finite element analyses.

  • 1509.
    Walander, Tomas
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Eklind, Alexander
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Carlberger, Thomas
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Stigh, Ulf
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Fatigue damage of adhesive layers: experiments and models2014In: Procedia Materials Science, ISSN 2211-8128, Vol. 3, p. 829-834Article in journal (Refereed)
    Abstract [en]

    Mode I fatigue crack growth at load levels close to the threshold is studied with the aim of improving the understanding of the fatigue properties. We also aim at identifying a suitable damage evolution law for large-scale simulation of built-up structures. A fatigue test rig is designed where up to six specimens are tested simultaneously. Each specimen is evaluated separately indicating the specimen-to-specimen variation in fatigue properties. A rubber-based and a PUR-based adhesive are tested. The two adhesives represent adhesives with very different material properties; the rubber adhesive is a stiff structural adhesive and the PUR adhesive is a soft modular adhesive. The experiments are first evaluated using a traditional Paris’ law approach. Inspired by an existing damage evolution law, a modified damage evolution law is developed based on only three parameters. The law is implemented as a user material in Abaqus and the parameters are identified. The results from simulations show a very good ability to reproduce the experimental data. With this model of fatigue damage, a zone of damage evolves at the crack tip. The extension of this zone depends on the stiffness of the adherends; stiffer adherends leads to a larger damage zone. This means that the rate of crack growth depends on the stiffness of the adherends. Thus, not only the state at the crack tip governs the rate of crack growth. This is in contrast to the results of a model based on Paris’ law where only the state at the crack tip, through the energy release rate, governs the rate of crack growth. This indicates that the threshold value of the energy release rate may depend on the stiffness of the adherends.

  • 1510.
    Walander, Tomas
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Eklind, Alexander
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Carlberger, Thomas
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Stigh, Ulf
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Rietz, Andreas
    Scania STC, Södertälje, Sweden.
    Prediction of mixed-mode cohesive fatigue strength of adhesively bonded structure using Mode I data2016In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 66, p. 15-25Article in journal (Refereed)
    Abstract [en]

    A cohesive zone model is presented for analyzing the fatigue life of an adhesive joint in the range of 104–106 load cycles. The parameters of the model are derived from Mode I double cantilever beam experiments. Fatigue experiments with adhesively joined components from the automotive industry are performed, and the results from the experiments are compared to the results of simulations. The error in the predicted fatigue strength is of the same order as the statistical deviation of the fatigue experiments, indicating that the simulation method produces acceptable predictions of the fatigue strength for applications in e.g. early product development.

  • 1511.
    Wallgren, Henric
    et al.
    University of Skövde, School of Technology and Society.
    Ytterby, Erik
    University of Skövde, School of Technology and Society.
    FÖRBÄTTRAD STYVHET AV KANTVIKMASKIN: Verktygsprismor2014Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Kantvikmaskin FUTURA PLUS 30 klarar idag att bocka en stålplåt, arbetsstycke, som är 3000 mm bred och 3 mm tjock med en acceptabel variation av bockradien. Målet med detta förbättringsarbete är att styvheten för de längsgående maskindelarna ska ökas, så att det är möjligt att bocka ett arbetsstycken som är 20 % tjockare än vad som är möjligt med dagens konstruktion. Genom att öka styvheten skall maskinen kunna hantera arbetsstycken av stål med en bredd upp till 3000 mm och en tjocklek upp till och med 3,6 mm med bibehållen variation av bockningsradie. Ökad styvhet innebär också att arbetsstycken med mindre tjocklek än den maximala kan bockas med större noggrannhet än dagen konstruktion. Detta kan leda till en större marknad för maskinen då kraftigare produkter eller produkter med en högre noggrannhet kan tillverkas med denna typ av maskin. Genom att optimera materialåtgången för maskindelarna minskas materialkostnaderna. Begränsningar i studien är att tillverkningskostnaden hos längsgående maskindelar skall förbli den samma som i dagens konstruktion.

    Genomgång av tidigare forskning gjord inom ämnet plåtbockning visar att erforderliga momentet för bockning kan beskrivas med hjälp av balkteori. Det konstateras att, enligt den linjärelastiska-idealplastiska materialmodellen, bockningsmomentet är proportionellt mot tjockleken i kvadrat för en balk. Detta samband används till en jämförelse mellan dagens maskinkonstruktion och en maskinkonstruktion som ska klara 20 % tjockare arbetsstycken. Detta samband och att deformationerna hos maskindelarna är linjärelastiska leder till att enhetslaster används.

    Studier av över- och under-prismorna visar att viss deformation kan avhjälpas med nya konstruktionsplåtar där en fotplåt för underprismat är det som mest reducerar deformationerna per viktenhet. Det slutgiltiga dimensioneringsförslaget leder till att maskindelarnas totala vikt minskas samtidigt som styvheten ökas till att klara 20 % tjockare arbetsstycken. Dock ökas antalet konstruktionsplåtar vilket kan leda till ökad produktionstid.

  • 1512.
    Wallin, Anton
    University of Skövde, School of Humanities and Informatics.
    SOCIAL REPRESENTETION OCH SPRÅK I DOKUMENTÄR MEDIA2013Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Hur påverkar språket som en intervju hålls på uppfattningen hos mottagaren? Med

    avstamp i teorin om social representation är detta huvudfrågan i arbetet. För att

    undersöka hur publiken av ett dokumentärt material påverkas beroende på det språk

    som talas skapades två videoklipp med intervjuer på olika språk. Materialet testades på

    en respondentgrupp som efteråt intervjuats om sin uppfattning av personerna i

    klippen. Analysen visade hur respondenterna tilldelade de båda personerna olika

    attribut, dels med anledning av språket, men även på grund av andra skäl. Resultatet

    visar hur språket kan påverka uppfattningen men fler variabler att undersöka kvarstår

    för framtida arbeten.

  • 1513.
    Wallin Johansson, Daniel
    University of Skövde, School of Engineering Science.
    KARTLÄGGNING AV VÄRDEFLÖDEOCH IDENTIFIERING AV SLÖSERIERFÖR ÄGGPRODUKTION2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Dava Foods in Skara has been the industry for this final year project where they processing egg in different conditions. For this project has the process where they manufacture protein drinks as they sold to the stores been in focus. The main goals for the project were to bring a value streaming map of the current state of the production and suggest improvements based on this map. The second goal was to find which types of wastes that occur and find improvements.

    To create an understanding of the existing process, an analysis was made where the stream was observed. Observations and interviews were used to collect data for the project. The analysis of the exciting process has been based on for the implementation stage.

    During the implementation stage was different tools used to collect data. PDCA has been a tool where was followed during the whole project. The value streaming map has been a central tool which was used to bring out a value streaming map. To collect the times which was needed for the value streaming map a stopwatch was used.

    The project result in different improvement proposal where many of the proposals included was to automate the processes. One solution was to change the operator against a robot cell which would streamline the process which would result in a lower throughput. Change machine was another solution where many stops occur. A full automation concept was suggested to combine these two suggestions, where both a robot and a machine was bought. The last suggestion of the value streaming map was about to just produces one product at a time. Within the wastes were three suggestions given where maintenance was the best solution to reduce the wastes. To determine which one of the suggestions was the best solution a pick chart was used to priority how hard the suggestion was and benefit.

    The conclusion was to purchasing the machine where stops frequently occur. This suggestion would create a higher efficiency in the production at the same time where the condition about price would give the best solution. Improvements of maintenance would also result as the best solution to increase the efficiency for the current machines and reduce the number of stops.

  • 1514.
    Wallin, Pontus
    University of Skövde, School of Informatics.
    Användning av Evolutionära algoritmer för att upptäcka balansproblem i strategispel.2015Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Spelbalans är ett viktigt koncept inom spelutveckling, generellt sett så anses datorspel där det finns många olika strategier för att vinna, och där alla är effektiva, vara bättre än spel där det bara finns några få effektiva strategier. För att uppnå bra spelbalans krävs ofta att mycket tid med att testa spelet med speltestare för att hitta strategier som kan förstöra denna balans. Arbetet undersöker om man kan snabba upp speltestningsprocessen genom att låta en evolutionär algoritm automatiskt undersöka ett spels strategirymd, och sedan dra slutsatser på hur spelet skulle ändras för att förbättra spelbalansen. Resultatet pekar på att metoden kan hantera extremfall, men förlorar effektivitet vid en viss gräns. I framtiden kan algoritmens effektivitet förbättras genom att förbättra sättet algoritmen tar ekonomiska faktorer i åtanke.

  • 1515.
    Wallsin, Daniel
    University of Skövde, School of Humanities and Informatics.
    Blandning av objekt från olika tidsepoker i Sanctum: Uppfattas avvikelsen om texturen modifierats?2012Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta arbete är att undersöka om det är möjligt att blanda objekt från olika tidsepoker i spelet Sanctum utan att spelaren observerar någon avvikelse. Detta är intressant då vi kan se om det är texturen eller formen som är mest dominant när det gäller att smälta in i en miljö, vilket kan användas för att förenkla arbetsprocesser vid skapade av spelgrafik eller vid design av miljöer, både utanför och innanför virtuella miljöer.

    Jag har valt att använda en kvantitativ undersökning där testpersonerna fick se på ett kort filmklipp med fyra objekt med två olika texturer, vardera placerade i en spelmiljö med två områden från olika tidsperioder i Sanctum. Därefter fick testpersonerna svara på frågor om de hade observerat något objekt som avvek från sin miljö och i så fall om det var texturen eller formen som avvikit. De fick sedan veta vad undersökningen går ut på och fick sedan se på filmklippet en gång till med möjligheten att spola och pausa i filmklippet. Därefter fick testpersonerna svara på frågor en gång till om objekt som avvikit och i så fall vad som avvek.

    Undersökningen har visat att det inte är möjligt att blanda objekt från olika tidsepoker om texturen inte modifierats utan att en avvikelse observeras. Däremot visar resultaten från undersökningen att det är möjligt att blanda objekt från olika tidsepoker om texturen modifierats. Det är lättare att blanda små objekt från olika tidsepoker, än att blanda stora objekt, då avvikande form lättare observeras när objekten blir större. Undersökningen tyder också på att det är  mindre chans att en avvikelse observeras om ett objekts textur modifierats för att passa in i ett mörkt område, än objekt vars textur modifierats för att passa in i ett ljust område.

  • 1516.
    Wang, Jiacheng
    et al.
    University of Skövde, School of Engineering Science.
    Domingos, Luzaisso
    University of Skövde, School of Engineering Science.
    Developing of Data Logging System for Flow Test Station in Industrial Laboratory2016Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    CEJN is a leading transnational company with long history and professional background providing high-tech quick connect products in global market. The headquarters of the com-pany in Skövde, Sweden, is the birthplace and core location of the entire corporation. In the headquarters, the engineer tests their products at their flow test laboratory. In the laboratory, there are flow test stations for all product ranges. Within them, the most basic are flow test benches for air, water and hydraulic oil products. The flow test benches are aim to test the products under International/Swedish standard conditions to determine the performance.

    This project is aimed in upgrading the test benches by engineering both hardware and soft-ware, to achieve higher level of automation of the data logging system used in the lab. All three test benches were designed and installed following requirements in corresponding in-ternational standards. The principles of testing are similar, but they are not developed from the same era, and the automation level of each test bench differs. As a result, the need of up-grading in the benches is different.

    In the laboratory, the recorded test results are reorganized and processed by a report genera-tor developed on Microsoft Excel. The Excel report generator is used for organize test results, calibrate the deviation of the instruments, calculate the flow coefficient of the product, gener-ate performance diagrams of the products, generate test reports for different purpose of use, and save the test data and results on the server of the company.

    Above all, an upgrade of the data logging system for the three flow test benches was needed. Depending on the conditions of each test bench, the project is implemented and designed the following three parts:

    • A hardware upgrading (flow rate computer) for the air flow test benchA new signal indicating device for replacing the old flow rate computer is purchased from Italy by the company. The new instrument contains filter function to stabilize the flow rate value.

    • A software upgrading (Excel report generator) for all the test benchesVisual Basic for Applications (VBA) programming language is used for developing functions such as data communication, signal decoding and user interface developing in Excel.

    • Develop of an automated data visualizing system for the air flow test benchData communication from the new instrument to a PC through serial port and Mod-bus RTU interface is established. The data visualizing function is compiled in the Ex-cel report generator for the air flow test, realized by VBA programming.

  • 1517.
    Wang, Jinjiang
    et al.
    University of Connecticut, Storrs, CT, USA.
    Gao, Robert X.
    University of Connecticut, Storrs, CT, USA.
    Yan, Ruqiang
    Southeast University, Nanjing, China.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    An EEMD and ICA-based Integrative Approach to Wind Turbine Gearbox Diagnosis2013In: Eighth CIRP Conference on Intelligent Computation in Manufacturing Engineering / [ed] Roberto Teti, Elsevier, 2013, Vol. 12, p. 133-138Conference paper (Refereed)
    Abstract [en]

    Increasing demand on energy has accelerated research on improving the reliability of wind turbines. As a critical component in wind turbine drivetrains, the majority of gearbox failures have shown to initiate from bearing failures. The low signal-to-noise ratio and transient nature of bearing signals pose significant difficulty for bearing defect diagnosis at the incipient stage. For improved bearing diagnosis, this paper presents a new method that integrates ensemble empirical mode decomposition (EEMD) with independent component analysis (ICA) to effectively separate bearing and gear meshing signals, without requiring a priori information on rotating speeds or bandwidth. The method first decomposes sensor measurement into a series of intrinsic mode functions (IMFs) as pseudo multi-channel signals, by means of EEMD, to satisfy the requirement by ICA for redundant information. ICA is performed on the IMFs to separate defective bearing components from gear meshing signal. Enveloping spectrum analysis is then performed to identify bearing structural defects. Both numerical and experimental studies have demonstrated the merit of the developed new method in improving gearbox diagnosis.

  • 1518.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    A Novel Collaborative Planning Approach for Digital Manufacturing2010In: Proceedings of the 6th CIRP-Sponsored International Conference on Digital Enterprise Technology / [ed] George Q. Huang, K. L. Mak, Paul G. Maropoulos, Berlin, Heidelberg: Springer Berlin/Heidelberg, 2010, p. 939-955Conference paper (Refereed)
    Abstract [en]

    The objective of this research is to develop methodology and algorithms for web-based digital manufacturing, supported by real-time monitoring for dynamic scheduling. This paper presents in particular an integrated approach for developing a web-based system, including distributed process planning, real-time monitoring and remote machining. It is enabled by a Wise-ShopFloor (Web-based integrated sensor-driven e-ShopFloor) framework targeting distributed yet collaborative manufacturing environments. Utilizing the latest Java technologies (Java 3D and Java Servlet) for system implementation, this approach allows users to plan and control distant shop floor operations based on runtime information from the shop floor. Details on the principle of the Wise-ShopFloor framework, system architecture, and a proof-of-concept prototype are reported in this paper. An example of distributed process planning for remote machining is chosen as a case study to demonstrate the effectiveness of this approach toward web-based digital manufacturing.

  • 1519.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Alternative Shop-Floor Re-Layout Design due to Dynamic Operation Changes2011In: ASME 2011 International Manufacturing Science and Engineering Conference, Volume 2, ASME Press, 2011, p. 127-133Conference paper (Refereed)
  • 1520.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    An ASP Approach to Adaptive Setup Planning and Merging for Available Machines2011Conference paper (Refereed)
  • 1521.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Challenges of Adaptive and Collaborative Manufacturing in the 21st Century2010In: Proceedings of the 14th International Conference on Machine Design and Production / [ed] M. Akkök et al., Middle East Technical University , 2010, p. 39-53Conference paper (Refereed)
    Abstract [en]

    Manufacturing has been one of the key areas that support and influence a nation’s economy since  the  18th  century.  Being  the  primary  driving  force  in  economy  growth,  manufacturing constantly serves as the foundation and contributes to other industries. In the past centuries, manufacturing contributed significantly to modern civilisation and created momentum that is driving today’s  economy. Despite of various revolutionary achievements, we are still facing challenges  when  striving  to  achieve  greater  success  in  manufacturing  in  the  21st  century. This paper highlights the challenges, particularly in adaptive and collaborative manufacturing, and offers a unique approach to solving the problems.

  • 1522.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Collaborations towards adaptive manufacturing2012In: Proceedings of the 2012 IEEE 16th International Conference on Computer Supported Cooperative Work in Design (CSCWD) / [ed] Liang Gao, Weiming Shen, Jean-Paul Barthès, Junzhou Luo, Jianming Yong, Wenfeng Li & Weidong Li, IEEE conference proceedings, 2012, p. 14-21Conference paper (Refereed)
    Abstract [en]

    This paper presents a new approach for real-time collaborations in adaptive manufacturing, including web-based remote monitoring and control of an industrial robot, and active collision avoidance for human-robot collaborations. It is enabled by using virtual 3D models driven by real sensor data and depth images of human operators. The objectives of this research are to significantly reduce network traffic needed for real-time monitoring over the Internet and to increase the human safety in a human-robot coexisting environment. The results of a case study show that the approach consumes less than 1% of network bandwidth of traditional camera-based methods, and is feasible and practical as a web-based solution.

  • 1523.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Combining Facility Layout Redesign and Dynamic Routing for Job-shop Assembly Operations2011In: Proceedings of 2011 IEEE International Symposium on Assembly and Manufacturing, IEEE, 2011, article id 5942302Conference paper (Refereed)
    Abstract [en]

    This paper presents a hybrid approach for facility layout redesign and dynamic job routing. More specifically, based on the source of uncertainty, the facility layout problem is split into two sub-problems and dealt with by two modules: relayout and find-route. Genetic algorithm is used where changes may cause a layout redesign of the entire shop, while function blocks are utilised to find the best sequence of robots for the new conditions within the existing layout. The method is verified in a case study of a hypothetic robotic assembly shop.

  • 1524.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Disassembly Planning by Motion Tracking Analysis2011In: Proceedings of International Conference on Remanufacturing, University of Strathclyde , 2011, p. 182-186Conference paper (Refereed)
    Abstract [en]

    This paper presents an integrated intuitive system for disassembly planning by actively tracking the motion of an experienced operator. It can also be used for operators training by combining a virtual reality (VR) environment with the motion tracking. The developed conceptual prototype for disassembly planning and training enables individuals to interact with a virtual environment in real time. It extends the technology of motion tracking and integrates it with virtual environment technology to create real-time virtual work cell simulations in which disassembly operators may be immersed with hands-on experiences. In addition to the operators training, the experimental results to date are presented to demonstrate the potential contributions of human skills in achieving effective disassembly planning for remanufacturing. It is expected that this approach will lead to environment-friendly and sustainable operations by conserving energy and cost that are first tested in a human-emerged virtual system.

  • 1525.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    International Journal of Manufacturing Research2012Collection (editor) (Refereed)
  • 1526.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2012Collection (editor) (Refereed)
  • 1527.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2012Collection (editor) (Refereed)
  • 1528.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    International Journal of Manufacturing Research2011Collection (editor) (Refereed)
  • 1529.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2011Collection (editor) (Refereed)
  • 1530.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2010Collection (editor) (Refereed)
  • 1531.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2010Collection (editor) (Refereed)
  • 1532.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2010Collection (editor) (Refereed)
  • 1533.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2009Collection (editor) (Refereed)
  • 1534.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2009Collection (editor) (Refereed)
  • 1535.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    International Journal of Manufacturing Research2011Collection (editor) (Refereed)
  • 1536.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    International Journal of Manufacturing Research2011Collection (editor) (Refereed)
  • 1537.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2009Collection (editor) (Other academic)
  • 1538.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Overview of an adaptive setup planning approach for job shop operations2009In: ASME 2009 International Manufacturing Science and Engineering Conference, Volume 1: Advances in Manufacturing Process Planning and Scheduling, ASME Press, 2009, p. 221-229Conference paper (Refereed)
    Abstract [en]

    This paper presents an overview of an adaptive setup planning system that considers both the availability and capability of machines on a shop floor. It integrates scheduling functions at setup planning stage, and utilizes a two-step decision-making strategy for generating machine-neutral and machine-specific optimal setup plans. The objective is to enable adaptive setup planning for dynamic machining job shop operations. Particularly, this paper documents basic algorithms and architecture of the setup planning system for dynamically assigned machines. It is then validated through a case study.

  • 1539.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Planning towards enhanced adaptability in digital manufacturing2011In: International journal of computer integrated manufacturing (Print), ISSN 0951-192X, E-ISSN 1362-3052, Vol. 24, no 5, p. 378-390Article in journal (Refereed)
    Abstract [en]

    This paper presents an integrated approach for developing a web-based system with enhanced adaptability, including distributed process planning, real-time monitoring and remote machining. The objective is to develop a new methodology and relevant processing algorithms for enhancing adaptability in digital manufacturing. This approach is enabled by a Wise-ShopFloor (Web-based integrated sensor-driven e-ShopFloor) framework targeting distributed yet collaborative manufacturing environments. Utilising the latest Java technologies (Java 3D and Java Servlet) for system implementation, it allows end-users to plan and control distant manufacturing operations based on runtime information from shop floors. Details on the principle of the Wise-ShopFloor framework, system architecture, and a prototype system are reported in this paper. An example of distributed process planning for remote machining is chosen as a case study to demonstrate the effectiveness of this approach toward web-based digital manufacturing.

  • 1540.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Wise-Shop Floor: Linking Virtual Manufacturing to Real Productions2009In: The International 3rd Swedish Production Symposium / [ed] B. G. Rosén, The Swedish Production Academy , 2009, p. 164-169Conference paper (Refereed)
    Abstract [en]

    This paper presents an integrated approach for web-based sensor-driven real-time monitoring and control. it is enabled by a Wise-ShopFloor (Web-based integrated sensor-driven e-ShopFloor) framework targeting distributed yet collaborative manufacturing environments. The objective of this research is to develop methodology and algorithms that utilise virtual manufacturing technology for real production. Details on the principle of the Wise-ShopFloor framework, system architecture, and a proof-of-concept prototype are reported in this paper. Remote machining is chosen as a case study to demonstrate the effectiveness of this approach toward web-based manufacturing.

  • 1541.
    Wang, Lihui
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Adamson, Göran
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Moore, Philip
    Mechatronics Research Centre, De Montfort University, Leicester LE1 9BH, United Kingdom.
    A review of function blocks for process planning and control of manufacturing equipment2012In: Journal of manufacturing systems, ISSN 0278-6125, E-ISSN 1878-6642, Vol. 31, no 3, p. 269-279Article, review/survey (Refereed)
    Abstract [en]

    Manufacturing in a job-shop environment is often characterized by a large variety of products in small batch sizes, requiring real-time monitoring for dynamic distributed decision making, and adaptive control capabilities that are able to handle, in a responsive way, different kinds of uncertainty, such as changes in demand and variations in production capability and functionality. In many manufacturing systems, traditional methods, based on offline processing performed in advance, are used. These methods are not up to the standard of handling uncertainty, in the dynamically changing environment of these manufacturing systems. Using real-time manufacturing intelligence and information to perform at a maximum level, with a minimum of unscheduled downtime, would be a more effective approach to handling the negative performance impacts of uncertainty. The objective of our research is to develop methodologies for distributed, adaptive and dynamic process planning as well as machine monitoring and control for machining and assembly operations, using event-driven function blocks. The implementation of this technology is expected to increase productivity, as well as flexibility and responsiveness in a job-shop environment. This paper, in particular, presents the current status in this field and a comprehensive overview of our research work on function block-enabled process planning and execution control of manufacturing equipment.

  • 1542.
    Wang, Lihui
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Adamson, Göran
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Moore, Philip
    De Montfort University, UK.
    Current Status of Function Blocks for Process Planning and Execution Control of Manufacturing Equipment2011In: Proceedings of the 21st International Conference on Flexible Automation and Intelligent Manufacturing, FAIM 2011: June 26 - 29th 2011, Feng Chia University, Taiwan / [ed] F. Frank Chen ..., Society of Lean Enterprise Systems of Taiwan , 2011, p. 963-973Conference paper (Refereed)
    Abstract [en]

    Manufacturing in a job-shop environment is often characterized by a large variety of products in small batch size, requiring real-time monitoring for dynamic distributed decision making, as well as dynamic control capabilities that are able to handle, in a responsive and adaptive way, different kinds of uncertainty, such as changes in demand and variations in production capability and functionality. In many manufacturing systems, traditional methods, based on offline processing performed in advance, are used. These methods are not up to the standard of handling uncertainty, in the dynamically changing environment of these manufacturing systems. Using real-time manufacturing intelligence and information to perform at a maximum level, with a minimum of unscheduled downtime, would be a more effective approach to handling the negative performance impacts of uncertainty. The objective of our research is to develop methodologies for distributed, adaptive and dynamic process planning as well a machine monitoring and control for machining and assembly operations, using event-driven function blocks. The implementation of this technology is expected to increase productivity, as well as flexibility and responsiveness in a job-shop environment. This paper, in particular, presents the current status in this field and a comprehensive overview of our research work on function block-enabled process planning and execution control of manufacturing equipment.

  • 1543.
    Wang, Lihui
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Cai, Ningxu
    Hyperion Technologies, Inc..
    Feng, Hsi-Yung
    University of British Colombia.
    Ma, Ji
    University of Western Ontario.
    ASP: An Adaptive Setup Planning Approach for Dynamic Machine Assignments2010In: IEEE Transactions on Automation Science and Engineering, ISSN 1545-5955, E-ISSN 1558-3783, Vol. 7, no 1, p. 2-14Article in journal (Refereed)
    Abstract [en]

    This paper presents a decision-making approach towards adaptive setup planning that considers both the availability and capability of machines on a shop floor. It loosely integrates scheduling functions at the setup planning stage, and utilizes a two-step decision-making strategy for generating machine-neutral and machine-specific setup plans at each stage. The objective of the research is to enable adaptive setup planning for dynamic job shop machining operations. Particularly, this paper covers basic concepts and algorithms for one-time generic setup planning, and run-time final setup merging for dynamic machine assignments. The decision-making algorithms validation is further demonstrated through a case study.

  • 1544.
    Wang, Lihui
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Feng, Hsi-Yung
    The University of British Columbia.
    Adaptive Manufacturing2011In: Journal of manufacturing systems, ISSN 0278-6125, E-ISSN 1878-6642, Vol. 30, no 3, p. 117-117Article in journal (Refereed)
  • 1545.
    Wang, Lihui
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Feng, Hsi-YungThe University of British Columbia.
    Journal of Manufacturing Systems2011Collection (editor) (Refereed)
  • 1546.
    Wang, Lihui
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Givehchi, Mohammad
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Web-DPP: An adaptive approach to planning and monitoring of job-shop machining operations2011In: Proceedings of the 7th CIRP-Sponsored International Conference on Digital Enterprise Technology, Athens, Greece, 2011, University of Patras , 2011Conference paper (Refereed)
    Abstract [en]

    Utilising the existing IT infrastructure, the objective of this research is to develop an integrated Web-based distributed process planning system (Web-DPP) for job-shop machining operations and their runtime execution monitoring. Our approach tries to engage a dispersed working group in a collaborative environment, allowing the team members to share real-time information through the Web-DPP. This paper analyses the challenges, and presents both the system design specification and the latest development of the Web-DPP system. Particularly, it proposes a two-tier architecture for effective decision making and introduces a set of event-driven function blocks for bridging the gap between high-level planning and low-level execution functions. By connecting to a Wise-ShopFloor framework, it enables real-time execution monitoring during the machining operations, locally or remotely. The closed-loop information flow makes adaptive planning possible.

  • 1547.
    Wang, Lihui
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Givehchi, Mohammad
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Adamson, Göran
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    A sensor-driven 3D model-based approach to remote real-time monitoring2011In: CIRP annals, ISSN 0007-8506, E-ISSN 1726-0604, Vol. 60, no 1, p. 493-496Article in journal (Refereed)
    Abstract [en]

    This paper presents an integrated approach for remote real-time monitoring of manufacturing operations. It is enabled by using virtual 3D models driven by real sensor data. The objectives of this research are twofold: (1) to significantly reduce network traffic for real-time monitoring over the Internet: and (2) to increase the controllability of manufacturing systems from anywhere in a decentralised environment. Particularly, this paper covers the principle of the approach, system architecture, prototype implementation, and a case study of remote control of a robotic assembly cell. Compared with camera-based monitoring systems, our approach only consumes less than 1% of its network bandwidth, feasible and practical as a web-based portable solution. (C) 2011 CIRP.

  • 1548.
    Wang, Lihui
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Givehchi, Mohammad
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Schmidt, Bernard
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Adamson, Göran
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Robotic Assembly Planning and Control with Enhanced Adaptability2012In: 45th CIRP Conference on Manufacturing Systems 2012 / [ed] G. Chryssolouris, D. Mourtzis, Elsevier, 2012, Vol. 3, p. 173-178Conference paper (Refereed)
    Abstract [en]

    The dynamic market today requires manufacturing companies to possess high degree of adaptability and flexibility in order to deal with shop-floor uncertainties. Such uncertainties as missing tools, part shortage, job delay, rush-order and unavailability of resources, etc. happen more often in assembly operations. Targeting this problem, this research proposes a function block enabled approach to achieving adaptability and flexibility in assembly planning and control. In particular, this paper presents our latest development using a robotic mini assembly cell for testing and validation of a function block enabled system capable of assembly and robot trajectory planning and control. It is expected that a better adaptability can be achieved by this approach.

  • 1549.
    Wang, Lihui
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Holm, Magnus
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Adamson, Göran
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Embedding a process plan in function blocks for adaptive machining2010In: CIRP annals, ISSN 0007-8506, E-ISSN 1726-0604, Vol. 59, no 1, p. 433-436Article in journal (Refereed)
    Abstract [en]

    This paper presents a function block enabled approach towards adaptive process planning and machining. A two-layer structure of supervisory planning and operation planning is proposed to separate generic data from machine-specific ones. The supervisory planning is only performed once, in advance, at the shop level to generate machine-neutral process plans, whereas the operation planning is carried out at runtime at the machine level to determine machine-specific operations. Such adaptive decision making is facilitated by event-driven algorithms embedded in the function blocks. It is expected that the new approach can greatly enhance the dynamism of fluctuating job-shop machining operations.

  • 1550.
    Wang, Lihui
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Keshavarzmanesh, Shadi
    Univ Western Ontario, Dept Mech & Mat Engn, London, ON, Canada .
    Feng, Hsi-Yung
    Univ British Columbia, Dept Mech Engn, Vancouver, BC V6T 1W5, Canada.
    A function block based approach for increasing adaptability of assembly planning and control2011In: International Journal of Production Research, ISSN 0020-7543, E-ISSN 1366-588X, Vol. 49, no 16, p. 4903-4924Article in journal (Refereed)
    Abstract [en]

    Today's market turbulences cause frequent changes in manufacturing environments. Products diversity, small batch sizes and short life cycles have increased production uncertainties and created a highly dynamic shop floor environment. One essential requirement of such an environment is an adaptive planning and control system that is sufficiently agile to respond to the variety of production requirements and enable easy system reconfiguration at run-time. When developing a product, assembly is a key area that impacts the manufacturing system's responsiveness to the changes. In this research, a framework and a new methodology are introduced to increase the adaptability and autonomy of job-shop assembly process planning and control using function blocks (FBs). A function block is a reusable functional module with an explicit event-driven model, and provides for data flow and finite state automata based control. Event-driven and FB-enabled decision-making is unique in adaptive assembly planning and control. It is explained through an example of a two-robot assembly work cell, where the result of the adaptive planning is wrapped in FBs for execution. The proposed approach has been implemented and simulated using Matlab Simulink in the case study. The simulation demonstrates how this approach would increase the adaptability and responsiveness to changes that may occur regularly in dynamic job-shop assembly operations.

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