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  • 51.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Hanson, L.
    Högberg, D.
    Örtengren, Roland
    Chalmers tekniska högskola.
    Lämkull, D.
    Virtal Methods and IT, Volvo Cars, Gothenburg.
    Rhen, I.M.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Ergonomic Risk Assessment Using Motion Data Modelling, Exposure Calculation and Comparison with an Epidemiological Reference Database2014In: International Journal of Human Factors Modelling and Simulation, ISSN 742-5549Article in journal (Refereed)
  • 52.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Lämkull, D.
    Virtal Methods and IT, Volvo Cars, Gothenburg.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Örtengren, Roland
    Chalmers tekniska högskola.
    Extending Functionalities of DHM Tools Using Motion Databases2014In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219Article in journal (Refereed)
  • 53.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Lämkull, D.
    Virtal Methods and IT, Volvo Cars, Gothenburg.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Örtengren, Roland
    Chalmers tekniska högskola.
    Functionalities of DHM Tools Using Motion Databases2014In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219Article in journal (Refereed)
  • 54.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering. Chalmers University of Technology.
    Paul, G.
    School of Public Health and Social Work, Queensland University of Technology, Brisbane.
    Lämkull, D.
    Virtal Methods and IT, Volvo Cars, Gothenburg.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Örtengren, Roland
    Chalmers tekniska högskola.
    Standardization of Motion Databases for DHM Applications: Challenges, Issues and considerations2014In: Article in journal (Refereed)
  • 55.
    Kjellerås, Jerry
    University West, Department of Engineering Science, Division of Automation Systems.
    Analys av ett presshärdningsverktyg2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Press Hardening is a technique in which a sheet of boron steel under very high pressure is formed and hardened. The company AP&T, which manufactures sheet metal forming presses, got a problem with a press hardening tool they had constructed. The customer had reject the design with the argument that the tool was to weak and that it at the press operation would deform too much. AP&T´s response was to design a reinforcement to the tool, but even with the reinforcement the client meant that the tool was too weak. In this work, finite element analyses has been performed in order to judge if the tool without and with reinforcement is stiff enough.

    The analyses show that the stresses in the tool are very low relative to the yield strength of the material of the tool and that the deformations are so small that they will not affect the end-product more than marginally. The result also shows that the design of one of the tool parts is worse than the others, since "guiding grooves" in the part is weakening it so that the biggest deformation is located there. The analysis of AP&T's reinforced tool showed no significant difference in deformation or stress. The reinforcement was redesigned taking into account the shortcomings of AP&T´s reinforced tool. A new analysis showed that the deformation decreased, especially at the "guide grooves".

  • 56.
    Larsson, Mats
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Holm, Oskar
    University West, Department of Engineering Science, Division of Automation Systems.
    Förstudie gällande konvertering till bränslecellsbaserad elkraftsproduktion på Stena Vision.2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This feasibility study has been carried out onboard Stena Vision and it aims to investigate if a fuel cell conversion of the ships electrical power production plant is technically possible.

    Through studies of the ships construction, as well as laws and regulations regarding ships installations, the authors has constructed a proposal for a new design for the electrical system. The proposal is presented in "bilaga B2".

    The authors also presents a design proposal for a new fuel system, adapted for the new fuel hydrogen. The new fuel system proposal is presented in "bilaga D".

    One of the most important conclusions in this thesis is that a full conversion, including the emergency generator, would demand a law amendment.

  • 57.
    Lennartson, Bengt
    et al.
    University West, Department of Engineering Science, Division of Automation Systems. University West, Department of Engineering Science, Division of Production Systems. Chalmers University of Technology, Department of Signals and Systems, Gothenburg, Sweden.
    Bengtsson, Kristofer
    Sekvensa AB.
    Wigstrom, Oskar
    Chalmers.
    Riazi, Sarmad
    Chalmers.
    Modeling and Optimization of Hybrid Systems for the Tweeting Factory2016In: IEEE Transactions on Automation Science and Engineering, ISSN 1545-5955, E-ISSN 1558-3783, Vol. 13, no 1, p. 195-205Article in journal (Refereed)
    Abstract [en]

    In this paper, a predicate transition model for discrete-event systems is generalized to include continuous dynamics, and the result is a modular hybrid predicate transition model. Based on this model, a hybrid Petri net including explicit differential equations and shared variables is also proposed. It is then shown how this hybrid Petri net model can be optimized based on a simple and robust nonlinear programming formulation. The procedure only assumes that desired sampled paths for a number of interacting moving devices are given, while originally equidistant time instances are adjusted to minimize a given criterion. This optimization of hybrid systems is also applied to a real robot station with interacting devices, which results in about 30% reduction in energy consumption. Moreover, a flexible online and event-based information architecture called the Tweeting Factory is proposed. Simple messages (tweets) from all kinds of equipment are combined into high-level knowledge, and it is demonstrated how this information architecture can be used to support optimization of robot stations.

  • 58.
    Leroy, Laurent
    University West, Department of Engineering Science, Division of Automation Systems.
    Automation of an assembly line for electrical enclosures by screw-fastening method: feasibility study: Master's thesis work2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The screw fastening method is widely used in manufacturing industry. Still, as it comes to automated solutions, special designs are often required.The current work consists of a feasibility study for the automation of the existing system based on the screw-fastening of the housing parts of electrical enclosures at ABB Kabeldon.A simulation using RobotStudio attends to provide answers to the success of the screw in-sertion and define specific requirements of the tool according to the enclosure design. As part of the outlined solution, a tool offsetting the driving of the screw has been designed in collaboration with Dessouter Tools according to the dimensional requirements of the task. A simulation based on the tool has been realised which shows no collisions nor reachability issues.Other requirements of the process automation are discussed. As underlined, it is difficult to be conclusive regarding the success of a full automation. Issues resulting from the galvanizing process are concern as it can result in mismatches and redundant errors in the automated screw insertion procedure and consequently jeopardize the reliability of the process. Only tests on real scale can satisfactory answer the reliability of the system.This work is set as a base for further discussion on the related subject and a support to consider implications of the implementation of the screw fastening method. Further investi-gations should be made.

  • 59.
    Lind, Per
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Dahlgren, Erik
    University West, Department of Engineering Science, Division of Automation Systems.
    Hur ett elnät kan visualiseras på ett överskådligt sätt med ett enlinjeschema i dpPower2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The municipal electric power company Leva i Lysekil is in need of a new one-line diagram. The one-line diagram should be compact and perspicuous and must fit on 2-3 A1 papers. The one-line diagram should be constructed in the commonly used program dpPower. The purpose of the examination paper is to meet Leva i Lysekils demands on a perspicuous diagram and an instruction how to place the substation to meet the demand. The result shows 379 substations that can be printed on three A1 papers and the one-line diagram show Leva i Lysekils electrical grid in a compact and perspicuous manner. The one-line diagram gives a rough estimate of where the substations are geographically located.

  • 60.
    Lindell, Erik
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Svensson, Magnus
    University West, Department of Engineering Science, Division of Automation Systems.
    Teknisk-ekonomisk utvärdering av lokalkraftslösningar2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Substations in the Swedish electric power network have a vital function regarding the supply of electric energy from producer to consumer. The substations are represented on different voltage levels in the network – but they all have one thing in common: The need for auxiliary power to function as intended.

    There are different options for the supply of substations auxiliary feed. In the thesis the following alternatives are described holistic: local transformer, external power subscription, auxiliary winding on ordinary transformer, and a new (for the Swedish market) alternative from ABB called SSVT (Station Service Voltage Transformer). The distinct solutions are characterized with different technical and economic aspects and associated pros and cons.

    The study evaluates the four different auxiliary power solutions from a holistic view. First, the underlying essential theory about auxiliary power and electrical power economy is explained. Afterwards, the technical and economical differences are visualized for each of the solutions, and in comparison to each other for each defined substation type; distribution, region and national substation.

    The company Vattenfall strives for the best technical-economical alternatives for their different types of substations and the report intends to act as a supportive document. From the report, the following results and conclusions can be obtained:

    • Distribution substation: Local transformer and auxiliary winding is recommended due the technical functionality relative to its equivalent economic aspects.

    • Region substation: Primarily, the auxiliary winding alternative is recommended, mostly because of the cost-effectiveness. There are fewer alternatives in this type of substation.

    • National substation: The auxiliary winding is recommended as local power solution.

    To sum up, all of the four alternatives fill the technical requirements, but consideration for which solution for which substation type must be done on a case to case basis.

  • 61.
    Lundin, Johan
    University West, Department of Engineering Science, Division of Automation Systems.
    Infästningsadapter för provning av passagerarairbag2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project has contained a development of a mounting adapter to be used for testing passenger airbags. The project started with the collection of customer requirements and this was done through interviews and observations of engineers and technicians at Autoliv. Phase two was to generate ideas and solutions and this was done by brainstorming. The developed solutions were ranked by using screening and a scoring matrix. The final concept from the scoring-matrix was an adapter with eight carriage bolts. A CAD model of the final concept was created. The FEM-analysis of the final concept showed that the developed adapter had low deformations and stresses during the passenger airbag deployment thus verifying that the concept can be used in the testing environment.

  • 62.
    Malmsköld, Lennart
    et al.
    University West, Department of Engineering Science, Division of Automation Systems. Volvo Technology.
    Örtengren, Roland
    Chalmers University of Technology, Department of Product and Production Development,.
    Svensson, Lars
    University West, Department of Economics and IT, Divison of Informatics.
    Improved Quality Output through Computer-Based Training: An Automotive Assembly Field Study2015In: Human Factors and Ergonomics in Manufacturing, ISSN 1090-8471, E-ISSN 1520-6564, Vol. 25, no 3, p. 304-318Article in journal (Refereed)
    Abstract [en]

    In this article, two field experiments, conducted in an automotive assembly plant, evaluate how computer-based training of operational sequences and related quality information can support the assembly performance of the operators. The experiments were performed during the launch of a new vehicle. A comparison was made of learning progress and quality performance between a reference group of operators that only had regular training and a test group for which some of the regular training was replaced with individual computer-based training. Both quantitative measures of the quality output and questionnaires and observations were used to evaluate the effects of computer-based training. The results show a clear positive difference in learning progress and improvements in quality output for the test group compared with the reference group. This combined with positive attitudes expressed by the operators and their team leaders shows that this type of training is an effective way to train operators during launches of new vehicles in automotive production. © 2014 Wiley Periodicals, Inc.

  • 63.
    Mellqvist, Roger
    University West, Department of Engineering Science, Division of Automation Systems.
    Kartläggning av faktorer som kan minska antalet återinkopplingar i elnätet2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In Sweden Vattenfall Eldistribution AB provides electrical power to approximatly 900000 customers, both private customers and business customers. The grid is operated from Trollhättan and it is the division Nätdrift's main purpose to, beside keeping the grid operating with a minimum of disturbances, to plan, optimize, manage and develop the operating systems.

    The society today is increasingly depending of an uninterrupted transmission of electricity and therefore it is important to make a survey of the factors that causes short interruptions in the grid. A short interruption is defined as an interruption that has a duration between 100 ms and 3 min. The regulations provided by the authorities do not include any demands regarding how frequent these short interruptions may occure in the grid. This is due to the fact that they are mostly caused by overvoltage from lightning storms, and therefore hard to predict. When lightning strikes on an overhead line, a breakdown of the insulation will occur due to overcurrent and a shortcut will ignite an arc between the wire and earth. This will start the phase-fault protection system to react and activate the feeder circuit breakers involved. This protection of the grid will cause a short interruption of the power supply before the automatic reclosing repowers the overhead line back to normal operating voltage.

    This thesis has been based on short interruptions caused by lightning and there has been no considerations taken to short interruptions occurring in grids with a voltage level below 1000 V.

    In this thesis a study of literature has been conducted from course literature, research and Vattenfalls internal documents. The result has been that a number of possible actions can be taken in consideration for making short interruptions less frequent. This thesis is also recommending that the survey of actors which are causing short interruptions continues. When doing so, the economical aspects should also be taken in consideration regarding the customers as well as the network company.

  • 64.
    Nilsen, Morgan
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Monitoring of laser beam welding by a non-intrusive optical sensor system using photodiodes2015In: Proceedings of JOM 18 International conference on joining materials, Helsingör, Danmark, april 26-29 2015, JOM-institute , 2015, p. 1-14Conference paper (Refereed)
    Abstract [en]

    Monitoring and control of automated laser beam welding is necessary in order to increase weld quality and to optimise the process. This paper presents an evaluation of an optic monitoring system using photodiodes, integrated coaxial into the laser welding tool to monitor the optical electromagnetic emissions from the process. Three photodiodes are used, one for the visual spectra, one for the reflected laser light and one for the infrared spectra.A survey of previous research regarding monitoring of welding using photodiodes have been conducted, it indicated the need for development of a high bandwidth monitoring system able to capture the fast dynamic events of the welding process. Based on this a monitoring system was developed and the frequency components of the monitored signals was analysed. Welding experiments, using a 1 μm YAG laser on nickel-based alloy sheet metal of different thicknesses, has also been conducted in order to evaluate the correlation between monitored signals and change of parameters effecting the weld quality. Laser power and laser focus was changed during the experiments.I was shown that a bandwidth of 30 kHz for the monitoring system would be sufficient to capture the interesting components of the signals from the photodiodes. A clear correlation between signal level from the sensor monitoring the infrared spectra and weld penetration was found and also a correlation between reflected laser light and laser beam focus. High intensity peaks was found in the signal from the sensor monitoring the visual spectra. It is assumed, but not confirmed, that they show the formation plasma in the key hole.

  • 65.
    Olsson, David
    University West, Department of Engineering Science, Division of Automation Systems.
    Effektivisering av tillverkningsprocess med avseende på materialflöden2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete har utförts på Uddevalla Finmekanik AB (UFAB), Uddevalla, och är inriktat mot att effektivisera tillverkningsprocessen av ett kontrollskåp med avseende på materialflöden. Huvudproblemet är att tillverkningsprocessen inte följer företagets övriga interna flöden. Syftet med rapporten var att framställa en nulägesanalys över materialflödet för att fastställa vilka komplikationer som uppstår, och var, samt generera förbättringsförslag som skall motverka problemen.

    För att genomföra arbetet på ett grundligt sätt användes flera olika metoder och förbättrings-verktyg. Data samlades in genom att utföra observationer och intervjuer med anställda i flö-dets olika avsnitt. Genom att tillämpa förbättrings- och ledningsverktyg kunde data struktu-reras och analyseras. En flödeskarta skapades för att användas i arbetet med att identifiera förbättringsförslag. Ur nulägesanalysen framkom att problem i materialförsörjningen genom-syrar större delar av tillverkningsprocessen. Problemen sträckte sig från mindre, avdelnings-specifika problem till problem som är länkade mellan olika avdelningar. Det framgick att standardiserade arbetssätt och tydliga rutiner är betydande orsaker till varför flödet är inef-fektivt. För att ge ytterligare tyngd till arbetet genomfördes en benchmarking på VBG Truck Equipment i Vänersborg med syfte att lokalisera likartade problem och hur de hanteras.

    En optimering av processen kräver både kort- och långsiktigt förbättringsarbete från företa-get. Att engagera all delaktig personal i förbättringsaktiviteter är en förutsättning för ständiga förbättringar. Arbetet presenterar kortsiktiga förbättringsåtgärder såsom lagerstrukturering, tydligt fördelat ansvar och effektivare, interna transporter vilka skall motverka direkta pro-blem. Att utbilda personal både i hantering av företagets databassystem samt om anledningen till varför vissa moment måste utföras är långsiktiga förbättringar som är en förutsättning för att säkerställa effektiviteten i materialförsörjningen.

  • 66.
    Paredes Buendia, Gemma
    University West, Department of Engineering Science, Division of Automation Systems.
    Robotized Deburring2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The superalloy Inconel 718 has low machinability. Therefore, the material removal processes are difficult to carry out in this material. The main goal of this thesis is to perform robotized deburring process in this material with the purpose to get smooth edges of the surface. For that, the simulation of the workcell has been performed in order to achieve more accuracy in the depth paths and the correct robot configuration in a faster and safer way. Moreover, the burrs on the workpiece have been measured by a microscope in order to analyze the size and locations of the burrs generated in the previous process of the workpiece (end milling process).

    Automation of deburring process sometimes requires complexities such as the force control with the purpose to avoid deformation of the piece. Several tests have been performed in the real cell in which the force during the process has been controlled. For that, FC system by ABB has been used which requires a specific calibration to get the correct measure of the force. The purpose to use FC is the validation of this system to control the force through speed and position changes and the estimatio n of the required force (which are based on the test results) to achieve the desired smooth edges of the workpieces..

  • 67.
    Runnemalm, Anna
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Ahlberg, Jörgen
    Linköping University.
    Appelgren, Anders
    University West, Department of Engineering Science, Division of Automation Systems.
    Sjökvist, Stefan
    Termisk systemteknik AB.
    Automatic Inspection of Spot Welds by Thermography2014In: Journal of nondestructive evaluation, ISSN 0195-9298, E-ISSN 1573-4862, Vol. 33, no 3, p. 398-406Article in journal (Refereed)
    Abstract [en]

    The interest for thermography as a method for spot weld inspection has increased during the last years since it is a full-field method suitable for automatic inspection. Thermography systems can be developed in different ways, with different physical setups, excitation sources, and image analysis algorithms. In this paper we suggest a single-sided setup of a thermography system using a flash lamp as excitation source. The analysis algorithm aims to find the spatial region in the acquired images corresponding to the successfully welded area, i.e., the nugget size. Experiments show that the system is able to detect spot welds, measure the nugget diameter, and based on the information also separate a spot weld from a stick weld. The system is capable to inspect more than four spot welds per minute, and has potential for an automatic non-destructive system for spot weld inspection. The development opportunities are significant, since the algorithm used in the initial analysis is rather simplified. Moreover, further evaluation of alternative excitation sources can potentially improve the performance.

  • 68.
    Runnemalm, Anna
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Surface crack detection using infrared thermography and ultraviolet excitation2014In: 12th International Conference on Quantitative InfraRed Thermography, 2014, p. 1-7Conference paper (Refereed)
    Abstract [en]

    High signal to noise ratio is important within non-destructive testing. To achieve automatic inspection, including automatic evaluation, it is even more important. Infrared thermography is a suitable method for automatic inspection. One drawback with thermography of metallic structures is that due to shiny surfaces the reflectance is high and the signal to noise ratio will be low. This paper presents results from surface crack detection with thermography using ultraviolet excitation. The tested component is a welded Inconel plate with a highly reflective surface. Ultraviolet excitation is shown to be a suitable excitation method and high signal to noise is achieved.

  • 69.
    Runnemalm, Anna
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Fernandez, Erik
    IK4-LORTEK, Ordizia, Spain.
    Garcia de la Yedra, Aitor
    IK4-LORTEK, Ordizia, Spain.
    Henrikson, Per
    GKN Aerospace Engine Systems, Trollhättan, Sweden.
    Thorpe, Nigel
    Tecnitest Ingenieros S.L, Madrid, Spain.
    Automatic thermography inspection of welded components with limited access2014In: Proceedings of 6th International Symposium on NDT in Aerospace, 12-14th November 2014, Madrid, Spain, 2014, p. 1-10Conference paper (Refereed)
    Abstract [en]

    Inspection of welds with limited access puts specific requirement on the NDT-method to be used. A non-contact method without the need for special surface preparation is preferable for fast and cost efficient inspection and with the possibility of automation. Infrared thermography has been known for quite a long time and is today mainly used for NDT inspection of composite structures. The technique is based on registering the heat conduction of the material of the surface of the structure. The method requires some kind of excitation resulting in a change of heat locally in the inspected area. In the study presented in this paper, different excitation methods are evaluated, such as continuous laser, flash lamp and induction. The study also includes conditions for miniaturization andautomation of the inspection methods. For welds difficult to access, thermography is a suggested as a possible inspection method.

  • 70.
    Runnemalm, Anna
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Henrikson, Per
    GKN Aerospace Engine System, Trollhättan.
    Ultraviolet excitation for thermography inspection of surface cracks in welded joints2014In: Nondestructive Testing and Evaluation, ISSN 1058-9759, E-ISSN 1477-2671, Vol. 29, no 4, p. 332-344Article in journal (Refereed)
    Abstract [en]

    Infrared thermography is a non-contact and full field inspection method which has proven to be suitable for automatic surface crack detection. For automatic analysis of the inspection results, a high signal-to-noise ratio (SNR) is required. In this paper an alternative excitation method, using ultraviolet (UV) illumination, is presented and evaluated. Artificial surface defects, so-called notches, in a titanium plate are detected both in the weld seam and in the heat affected zone. Notches with a size from 80 mm in width and 250 mm in length are detected. The SNR using UV illumination is compared with that using flash lamp excitation. The results show that UV illumination using a mercury lamp is a good alternative as excitation source for thermography when detecting surface cracks. To validate the excitation method, results from real surface cracks are included.

  • 71.
    Runnemalm, Anna
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Liu, Tongwein
    Ericsson, Mikael
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Appelgren, Anders
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Influence of Vibration Induced Disturbances in an Automatic Inspection Cell2013In: Robotics in Smart Manufacturing / [ed] Pedro Neto,António Paulo Moreira, 2013, p. 191-202Conference paper (Refereed)
    Abstract [en]

    In the modern manufacturing industry, quality assurance is important. Over the last few years, the interest in automatic inspection has increased and automatic non-destructive testing (NDT) has been introduced. A general automated inspection cell consists of a mechanized system for scanning and a computer system for automatic analysis of the data. In the manufacturing industry, it is preferable to use industrial robots as the scanning equipment since they offer great flexibility, excellent support organization and the in-house know-how is normally high. Another benefit is that a robot can carry different inspection equipment and an inspection cell can therefore include more than one NDT method. For an automatic analysis, high quality of the resulting data is essential. However, a non-stable condition of the NDT sensor mounted on the robotic arm may influence the results. This paper focuses on the influence of the vibration induced disturbances on the results from an NDT system. Vibration amplitude of a point to point robot movement on the robotic arm is measured. The influence of vibration disturbances on the inspection results are evaluated on the thermal images from a thermography system mounted on a six axis industrial robot. The thermal images taken by the system during the movement and after the stop of the robot are evaluated, and the influence of the vibration in these two situations is considered.

  • 72.
    Sabir, Hewr
    University West, Department of Engineering Science, Division of Automation Systems.
    Robotized deburring2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As the amount of industrial robots increases in the manufacturing industry, the developments in the area of automation of finishing methods has been attracting more attention. This thesis work introduces an automated system, performing deburring operations. A robot integrated with force control sensor holding a workpiece and a spindle engine holding a brush rigid within the working envelop of the robot.

    This work explores the approach of programming the robot and the force control sensor using offline programming in Robot Studio and online programming in direct contact with the robot. The advantages and disadvantages using the both methods is also concerned. The important part in order to automate the operation is the use of force control sensor which is introduced and programmed. The work is aiming to explore the importance of using force control and its functions during a deburring operation. Experiments of both including and excluding force control sensor is performed to analyse the ratio between force and distance. Instead of applying force on a workpiece during the operation is distance the workpiece being pushed into the brush emphasised. The experiments and results showed that it is possible to use only one force control sensor to analyse the ratio between force and distance for a specific tool. The calculated data can further be implement on other robots to only use distance as an input value and exclude force control sensor. The presented approach can be implemented in a manufacturing company applying this kind of operation to decrease the amount of force control sensors to only one and gain the same results and an economical benefit.

  • 73.
    Salih, Jim
    University West, Department of Engineering Science, Division of Automation Systems.
    An Adaptive Communication Method for an Automatic Guided Vehicle (AGV) in a production line: using RFID in a production line2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aggregate using of a flexible automation system in the industry area is gaining increasing attention from researchers in the last two decades. The most important factors influencing the automation system are the interaction techniques and the communication facilities used at the production line. There are different interaction techniques that have developed rapidly over the recent years within different manufacturing area for the sake of improving performance and quality of product.

    Automated Guided Vehicle (AGV) has been used as a flexible goods transportation tool at fac-tories. This work is aiming to test and introduce an adaptive communication technique be-tween an AGV and a production line's components using Radio Frequency Identification (RFID) system, which can be used in the manufacturing area.

    In this report, related works and titles to understand and achieve the goal has been discussed. As a background, AGV, RFID and communication techniques have also been discussed.This project provides a solution on how AGV communicates with the robot in a production line by using RFID systems and sensors. The proposed solution has been imple-mented and tested in order to get applicable results. The implementation phase is done us-ing an AGV, robot, RFID system (RFID reader and tags) and raspberry pi (RPI). In addition, the software used to make this components work includes AGV program (to control the AGV), RAPID program (to program the robot) and C program (is used in the RPI to receive the data from the RFID reader and resend it to the robot).

    The first test is conducted to determine AGV's accuracy, i.e. positioning accuracy or stop position in front of the robot. The importance of accuracy test helps in avoiding damage of goods and other unexpected consequences that can be caused by the lack of accuracy of the robot. Other tests aim to determine the suitability of the system and that the RFID, as a communication technique, is functioning properly.

    Some major benefits of the provided solutions include testing and proving that RFID can be used as a communication tool in the production line especially in the transportation of goods between different worksites and the capability of using RPI as a coordinating tool instead of ordinary computers. This fact can contribute in increasing the flexibility of production lines.

  • 74.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Operator bias in the estimation of arc efficiency in gas tungsten arc welding2015In: Soldagem & Inspeção, ISSN 0104-9224, E-ISSN 1980-6973, Vol. 20, no 1, p. 128-133Article in journal (Refereed)
    Abstract [en]

    In this paper the operator bias in the measurement process of arc efficiency in stationary direct current electrode negative gas tungsten arc welding is discussed. An experimental study involving 15 operators (enough to reach statistical significance) has been carried out with the purpose to estimate the arc efficiency from a specific procedure for calorimetric experiments. The measurement procedure consists of three manual operations which introduces operator bias in the measurement process. An additional relevant experiment highlights the consequences of estimating the arc voltage by measuring the potential between the terminals of the welding power source instead of measuring the potential between the electrode contact tube and the workpiece. The result of the study is a statistical evaluation of the operator bias influence on the estimate, showing that operator bias is negligible in the estimate considered here. On the contrary the consequences of neglecting welding leads voltage drop results in a significant under estimation of the arc efficiency. © 2015, Universidade Federal de Uberlandia. All rights reserved.

  • 75.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Operator influence on the estimation of arc efficiency in gas tungsten arc welding2013In: JOM-17 - International Conference on Joining Materials, 5-8 May 2013, Helsingør, Denmark. Proceedings / [ed] Osama Al-Erhayem, JOM-Institute , 2013Conference paper (Other academic)
    Abstract [en]

    In this paper the operator bias in the measurement process of arc efficiency in stationary direct current electrode negative gas tungsten arc welding is discussed. An experimental study involving 15 operators (enough to reach statistical significance) has been carried out with the purpose to estimate the arc efficiency from a specific procedure for calorimetric experiments. The measurement procedure consists of three manual operations which introduces operator bias in the measurement process. An additional relevant experiment highlights the consequences of estimating the arc voltage by measuring the potential between the terminals of the welding power source instead of measuring the potential between the electrode contact tube and the workpiece. The result of the study is a statistical evaluation of the operator bias influence on the estimate, showing that operator bias is negligible in the estimate considered here. On the contrary the consequences of neglecting welding leads voltage drop results in a significant under estimation of the arc efficiency.

  • 76.
    Sikström, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science, Division of Automation Systems.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Automation Systems. University West, Department of Engineering Science, Division of Production Systems. Chalmers University of Technology, Department of Signals and Systems,Gothenburgh, Sweden.
    Model based feedback control of gas tungsten arc welding: An experimental study2015In: Automation Science and Engineering (CASE), 2015 IEEE International Conference on, IEEE conference proceedings, 2015, p. 411-416Conference paper (Refereed)
    Abstract [en]

    In order to obtain high structural integrity and joint performance in welding a transient heat conduction model has been utilized to design a model based feedback controller.Gas tungsten arc welding of work-pieces of austenitic steel have been simulated by the finite element method. The basis for controller design is a low order model obtained from parametric system identification. The identification has been performed both on the finite element simulation and on physical welding. The low order model responses show a good agreement with both the finite element simulation result and the physical process response. An experimental study has been performed to verify the approach. This study also explores what experiments are needed for a successful design. It is shown that model based control successfully mitigates perturbations that occur during welding.

  • 77.
    Sikström, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Production Engineering.
    Heat input and temperatures in welding2013In: JOM-17 - International Conference on Joining Materials, JOM-Institute , 2013Conference paper (Refereed)
    Abstract [en]

    A key feature in welding is the energy supplied, in order to join the work pieces together. For all fusion welding methods, the supplied energy is so high that the work-piece joint surfaces are melted and fused together. The energy supplied is then transported away, mainly by conduction through the base materials. The temperature of the weld decreases and a solid joint is eventually formed. This may then undergo phase transformations and finally the weld joint reaches ambient temperature.

    The thermal history of a welded joint has a large effect on the microstructure and mechanical properties. Welding metallurgist therefore consider the cooling time t8/5 as crucial to understand the resulting properties of a joint in steel structures. The cooling time is influenced by several factors, like heat input, base material thickness, base material thermal properties, preheat an interpass temperatures etc. Regarding the heat input, the efficiency of the welding arc has for a long time been debated, i.e. how much of the arc energy really goes into the weld. Large efforts are being made to measure this very accurately.

    Another significant research field has been to measure or calculate the cooling time of welds, in particular t8/5. However, this cooling time is affected by the arc energy and by the arc efficiency.

    In a more macroscopic sense, it has been shown that the temperature of a welded structure can vary with the presence of for example internal heat sinks. Such variations may affect macroscopic properties like penetration. One way to ensure constant condition in terms of temperature could be to increase the heat input if the temperature decreases. However, how such variations affect for example the cooling rate has not been studied.The aim of the present paper is to report some experimental results regarding cooling rate in welded joints and put this into context of arc efficiency and temperature regulations and also discuss how the cooling rate may be affected in more production like welding situations.

  • 78.
    Sikström, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Nilsen, Morgan
    University West, Department of Engineering Science, Division of Automation Systems.
    Vision systems for in‐process monitoring of laser beam welding2015In: Proceedings of JOM 18 International conference on joining materials, Helsingör, Danmark, april 26-29, 2015, JOM-Institute , 2015, p. 1-8Conference paper (Refereed)
    Abstract [en]

    This paper addresses the issue of evaluating an optical vision system to be integrated with a 1μm laser beam welding tool for process monitoring. The boundary conditions for the system performance and system nature imposed by the needs in industrial production is highlighted. Initial welding experiments have been executed in order to understand the applicability of the vision system. The evaluation includes considerations on the required sensor bandwidth. The need for time synchronized data is emphasized and the use of numerical algorithms for enhancing the estimation and detection performanceof the system is discussed. The results shows a good potential for the system to give robust process information to be used in monitoring and control.

  • 79.
    Sikström, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Nilsen, Morgan
    University West, Department of Engineering Science, Division of Automation Systems.
    Eriksson, Ingemar
    GKN Aerospace, Trollhättan, Sweden.
    Optical Methods for In-Process Monitoring of Laser Beam Welding2014In: Proceedings of the 6th International Swedish Production Symposium 2014 / [ed] Stahre, Johan, Johansson, Björn & Björkman, Mats, 2014, p. 1-9Conference paper (Refereed)
    Abstract [en]

    This paper addresses the issue of evaluating and selecting optical sensors to be integrated with a 1μm laser beam welding system. The method used for this evaluation is mainly a survey of relevant research litterature. The result of this work is a matrix showing the different methods and distinct features related to relevant process conditions that can be estimated or detected with respective methods. This evaluation also includes considerations on the required sensor bandwidth in relation to inertia and time constants in the physical process.

  • 80.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Automation Systems.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Cooling rate effect on temperature controlled FSW process2015Conference paper (Refereed)
    Abstract [en]

    A continuous trend towards more demanding jointgeometries is imposed across various manufacturingindustries. During Friction Stir Welding (FSW) of suchcomplex geometries, the surrounding environment playsan important role on the final weld quality, especially inthermal aspects. In order to guarantee a consistent weldquality for different conditions, in-process weldingparameter adaptation is needed.This paper studies the effect of the cooling rate onmechanical properties for temperature controlled FSW byusing different backing bar materials. A new temperaturesensor solution, the Tool-Workpiece Thermocouple(TWT) method [1], was applied to measure thetemperature during welding. A FSW-robot equipped withtemperature and force feedback control was used, whererotation speed was varied to maintain a constant weldingtemperature. AA7075-T6 lap joints were performed withand without temperature control. The cooling rate duringwelding was acquired and macrographs and mechanicalproperties were evaluated for each weld. The rotationspeed offered a fast response promoting the heat inputnecessary to weld at the set temperature. Temperaturecontrolled welds presented a better behaviour undertensile loads. The results prove that temperature controlusing the TWT method is suitable to achieve higher jointquality and provides a fast setup of optimal parameters fordifferent environments.The work presented is an important step in the processoptimization through feedback control which willconsider not only the operational parameters of theprocess as such but also the resulting quality of the joint.

  • 81.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Automation Systems.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    TWT method for temperature measurement during FSW process2015In: The 4th international Conference on scientific and technical advances on friction stir welding & processing, San Sebastian, Spain, 2015, p. 95-98Conference paper (Refereed)
    Abstract [en]

    Friction stir weld (FSW) has generated a high interest in many industry segments in the past 20 years. Along with new industrial challenges, more complex geometries and high quality demands, a better control of the welding process is required. New approaches using temperature controlled welding have been proposed and revealed good results. However, few temperature measurement methods exist which are accurate, fast and industrially suitable. A new and simple sensor solution, the Tool-Workpiece Thermocouple (TWT) method, based on the thermoelectric effect was recently developed.This paper presents a calibration solution for the TWT method where the TWT temperature is compared to calibrated thermocouples inside the tool. The correspondence between both methods is shown. Furthermore, a calibration strategy in different aluminium alloys is proposed, which is based on plunge iterations. This allows accurate temperature monitoring during welding, without the need for thermocouples inside the tool.

  • 82.
    Sjöström, Robin
    University West, Department of Engineering Science, Division of Automation Systems.
    Kretsschemakonstruktion för Kapverk på SCA Edet bruk2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    One of the converting lines at SCA Edet Bruk AB has been shut down for a period of time. This line is about to be disassembled and replaced by a new converting line. The converting line has a sawmill that can be upgraded relatively easily and cost-effectively to meet up with the new demands from a new line. The purpose of this work is to establish the documentation and components required to electrically upgrade a sawmill. The main goal of this work is to provide a proposal on finished documents for electrical work and material orders.

    The existing equipment has been studied and investigated if they live up to the company's demands on the machine. An analysis of the situation has been conducted to investigate what needs to be upgraded or replaced, these changes have been drawn into new drawings. During rebuild of a machine there are safety regulations that have to be followed. These regulations have been studied to ensure the reliability and safety of components. The recommendation includes components like a new servo drive, a new control system by Siemens, a new security system by Pilz and the necessary changes in the electrical construction. The new components have been selected by functional and safety requirements, and by reasoning with the company's internal electrical designers.

    The finished material consists out of circuit diagrams constructed in the drawing program AutoCAD LT, and documents and recommendations of components that should be replaced. The main part of the results consists of a series of drawings that are included as an attachment. The drawings include a drawing series over a new control system, a new security system and drawings of the power and motor groups.

  • 83.
    Svenman, Edvard
    et al.
    University West, Department of Engineering Science, Division of Automation Systems. GKN Aerospace Sweden AB.
    Rosell, Anders
    GKN Aerospace, Sweden; Chalmers University of technology, Sweden.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Automation Systems.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science, Division of Automation Systems.
    Henrikson, Per
    GKN Aerospace, Sweden.
    Weld gap position detection based on eddy current methods with mismatch compensation2015In: Proceedings of JOM 18 International conference on joining materials, Helsingör, Danmark, april 26-29, 2015, JOM-institute , 2015, p. 1-9Conference paper (Refereed)
    Abstract [en]

    The paper proposes a method for finding the accurate position of narrow gaps, intended for seam tracking applications. Laser beam welding of butt joints, with narrow gap and weld width, demand very accurate positioning to avoid serious and difficult to detect lack of fusion defects. Existing optical and mechanical gap trackers have problems with narrow gaps and surface finish. Eddy current probes can detect narrow gaps, but the accuracy is affected by mismatch in height above the surface on either side of the gap. In this paper a non-contact eddy-current method, suitable for robotic seam tracking, is proposed. The method is based on the resistive and inductive response of two absolute eddy current coils on either side of the gap to calculate a position compensated for height variations. Additionally, the method may be used to estimate the values of height and gap width, which is useful for weld parameter optimization. To investigate the response to variations in height, the method is tested on non-magnetic metals by scanning one commercially available eddy current probe across an adjustable gap and calculating the expected response for a two-probe configuration. Results for gap position are promising, while mismatch and gap width results need further investigation.

  • 84.
    Svensson, Bo
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    P-SOP -€“ A multi-agent based control approach for flexible and robust manufacturing2015In: Robotics and Computer-Integrated Manufacturing, ISSN 0736-5845, E-ISSN 1879-2537, Vol. 36, p. 109-118, article id 1301Article in journal (Refereed)
    Abstract [en]

    In a truly flexible manufacturing system the description of the control strategy must be updated every day. Hence, a new way to handle changes in the environment down to control system deployment and production is required. This paper presents a novel approach, based on P-SOP, to handle multi-agent based control and verification. The P-SOP approach addresses flexibility, robustness and deployment in the best possible manner with the least waste of time and effort. P-SOP includes a description language where the control strategy based on actual circumstances easily can be defined. Based on the description multi-agents, to control the manufacturing, are automatically generated. An industrial advantage is that the multi-agent generator creates IEC 61131-3 PLC code that can be executed on standard PLC’s. This feature eliminates the need for experts in PLC programming and reduce deployment time to become more efficient. Hence, this flexibility enables small series down to one off production in a competitive way. With multi-agent control it is also possible to handle rebalancing due to market changes, scheduling of available humans, introduction of new part types, and rerouting due to a machine break down or planned service. The generated agents are not optimised for a final solution with specific timings. All decisions are made on-line and the generated solution adapts to the circumstances that arise. With the P-SOP multi-agents it is easy to manually remove or introduce parts to the manufacturing cell without disturbing the system, e.g. for manually random inspections, removal of parts due to restart. The formulated description language and the multi-agent generator has been successfully tested and evaluated in an industrial environment.

  • 85.
    Söderlund, Andreas
    University West, Department of Engineering Science, Division of Automation Systems.
    Identifiering av energiförluster i distributionsnät2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy efficiency is an issue that is becoming more relevant in today's society. By saving energy both the environment and economy benefits, but in order to do this, information about the existing energy losses must first be known. The purpose of this work is to identify the energy losses that occur in a distribution grid, and explore how the losses can be reduced.

    The selected measuring range covers one outgoing high voltage line, with four substations and a total of 895 customers of which one is a high voltage customer. Through measurements with power monitoring instruments transformer losses were calculated in the area's three substations. The losses proved to be negative, which in reality is impossible. When comparing between measurements made with power monitoring instruments in the stations and collected values from customer's meters, the loss proved to be unrealistically high. Investigation of the accuracy of the measurements performed in the stations showed that the accuracy is very low, so low that it cannot be certain if even reasonable values are accurate or not. Collected values from customer meters also proved to be very uncertain for shorter periods of time. Both these sources probably contribute to the faulty results.

    When the resulting energy loss could not be obtained by measurements with power monitoring instruments these were instead calculated over a period of one year. This was done through measured energy consumption of customers and theoretical values of losses obtained from the manufacturers of the investigated components. For the three transformers in the area the costs of energy losses were compared with the corresponding value if modern transformers were installed in their place. The results show that an exchange of equivalent size is not economically profitable, the cost saving for the losses is to low relative to the cost of the transformers. Losses have also been calculated for a selection of high and low voltage cables. No comparison of loss values between the existing cables and new modern was carried out because the values for these were found to be approximately equal.

    During the conducted measurements the harmonic levels of voltage and current on the low voltage side in the three stations were also measured. The result shows that harmonics occur but were within approved range during the periods of the conducted measurements.

  • 86.
    Söderlund, Monica
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Åkerblom, Cristopher
    University West, Department of Engineering Science, Division of Automation Systems.
    Framtagning av laboration kring kontrollmätning av jordtag2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report arose because the course Electrical ordinance and Electrical installation lacked an applied training session regarding control measurement of earth electrodes. The group's task was to develop a laboratory experiment in which one or more earth electrodes are being control measured. The lab would be included as a compulsory clause in the course.

    The goal is that the lab reflects a real control measurement of an earth electrode. It will include a geographic location, a teacher's guide and an answer key. The delimitations were that the lab would be conducted in the University West proximity within their security requirements. The time allocated for the lab should not exceed two to three hours per a group of two to three people. The lab is intended to be completed by the end of time; a written report is not required.

    Methods to carry out the thesis work consisted of gathering facts through literature, scientific articles, reports and relevant websites on the internet. Measurement sites were located by visual examination of the University's buildings and surrounding area. The lab was designed and tested to detect any flaws. An answer key of reference values was designed and suggestions for a teacher's guide were created.

    Earth electrode is the point or the device placed in the ground whose purpose is to divert electrical fault current from the connected plant to the surrounding land. It can take various forms depending on the type of the soil. Measurements of soil resistivity is made and recorded in tables which makes it easier to find reference values for new construction of earth electrode.

    The requirement for control measurement is to ensure that the reference value of the earth electrodes hasn't changed. The value could be checked by measurements with the high-current method, the low-current method, the resistance pliers' method or the screen control method.

    The work of designing the lab started with splitting it up in three sections, a preliminary part, a part where the measurements are made and the last part where the student are supposed to reflect on the results. The group chose measurement methods that fit the lab selected measurements and satisfies University West safety demands.

    Geographic location was designed regarding the need of three different test areas. The resulting earth electrode was found on the university's A-house. Currently there is no measurable individual earth electrode in the University's vicinity. Two areas with different soil conditions were discovered, where it would be possible to bury the two test earth electrodes where control measurement of single earth electrodes could be made. The presence of a teacher at the lab is recommended, both to make sure that the instrument is handled correctly and to answer questions. An answer key to the reference value was constructed.

    The lab was tested by the group, but only the parts of the lab that concerned the resulting earth electrode to do. The reason that not the whole lab was tested is that the university does not currently own any instruments and there were no individual earth electrodes to measure. This also led to that although it was planned, no independent test group could try the lab. The values found at the group's measurements were recorded as reference values in laboratory answer key

  • 87.
    Venugopal Reddy, Dhanush
    University West, Department of Engineering Science, Division of Automation Systems.
    A Genetic algorithm with shuffle to solve the job shop scheduling problem2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Job shop scheduling problems are computationally complex combinatorial optimization problems. Genetic algorithms have been used in various forms and in combination with other algorithms to solve job shop scheduling problems. A partially flexible job shop with precedence constraints increases this complex behaviour. There are two main parts to optimizing a job shop, the routing and the scheduling. The objective here is to get consistent optimal makespan using a genetic algorithm. This paper firstly, presents a representation of the considered partially flexible job shop scheduling problem, which helps take into account the precedence constraints and reduce situations of deadlock. It starts with the genetic crossovers for routing and then a random shuffle technique is used for scheduling the problem. The computational results have shown that the algorithm performs well in terms of finding a consistent optimal schedule for the given problem.

  • 88.
    Wu, Ronghua
    University West, Department of Engineering Science, Division of Automation Systems.
    Virtual Robotized NDT: Simulation in Robot Studio2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Human and machine cooperation has been developed for a long time to improve the productivity and because of advantages of the machine work, machine will play a more and more important role in the industrial production. To some extent, machine has already changed the world. This master thesis project was to use several robots build an automatic inspection line to inspect the wheel hub using the thermography with induction method. Three different methods are created in robot studio and the method with rotation tool was implemented as a demonstrator at PTC (production technology center).

    Compare the methods with each other and consider the limitations and productivity, the method with the rotation tool is the best choice for the company. The automation line includes several robots. In another words, the designed automation line can be considered to be several robot cells. Most sensors and calibration methods are set up due to the rules to build a robot cell. All signal analysis and processing are solved in the robot studio during the simulation process. Some needed robot cell components, equipment and different tools are used from the standard ABB robot studio library. Several special tools and equipment are designed and modelled in the NX and then converted to robot studio.

  • 89.
    Xin, Zhu
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Wang, Yimin
    University West, Department of Engineering Science, Division of Automation Systems.
    Quality assurance of nailed pallet2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis project is about quality assurance of nailed pallet, which is suggesting and evaluating a solution able to detect unknocked nails in a pallet at the company AvenPallen.

    The company AvenPallen is responsible for the production of different kinds of wood products, and these products are usually nailed in a robot cell. Due to variation in the wood, like unevenness of the density and tilt and twist of the boards, the nail may not be completely driven into the wood. This can results in an uneven smoothness of the pallet surface, and the production is unable to meet the requirements of customers and cause waste. To solve this problem the company AvenPallen manages to seek some systems to achieve quality assurance process in nails.

    The project has suggested four possible systems for detecting unknocked nails in a pallet. The suggested systems are mechanical inspection system, optical inspection system, vision technique system and 3D laser scanning system. By consider the situation of the company AvenPallen, there has been two improved system which are: optical inspection system and shadow inspection system. The optical inspection system uses the optical sensor to measure the height of nail to guarantee the quality of pallets. The shadow inspection system uses a CCD camera and a light to get some figures to measure the height of nails to ensure the quality of pallets. The two improved systems have been evaluated through tests. A suggestion of a possible analysis system is also included in the report.

    The report will give the analysis and result for the evaluation experiments and show that the shadow inspection system is a suitable inspection system with the possibility to analyse the measured data.

  • 90.
    Zhang, Cheng
    University West, Department of Engineering Science, Division of Automation Systems.
    Influence of surface roughness on thermography measurement2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This university Bachelor's Thesis was performed to explore the influence of surface roughness on the thermography measurement.

    Thermography is a non-destructive testing method which can be used to detect cracks. However, it is hard to define how the surface roughness influences the emissivity and the result of a thermography measurement, as well as how the angle of the excitation source influences the result. Therefore, this work aims to define how the heating angle and surface roughness influence the thermography measurement, define the relationship between surface roughness and emissivity for the same crack, and define the influence of the angles which composed of the heating source, the direction of crack and the direction of surface roughness on thermography measurement.

    In this report, the theories of radiation and Signal-to-noise ratio (SNR) were explained, clearly. Also, two kinds of experiments were set up. One is focus on how the heating angle influence the thermography measurement, the other is focus on how the angle of the heating source, in relation to the crack direction and the direction of surface roughness, influence the SNR value.

    The conclusions of these experiments are that the heating of a crack increases as the angle decreases (from wide side to narrow side) and the angle ofincreases (from horizontal to vertical). Moreover, the SNR value decreases as the surface roughness increases. For the same surface roughness, the SNR value increases with increased crack angle (0°, 45° or 90°) and with decreased sample position angle (horizontal, 45°or vertical). What is more, the higher surface roughness, the larger the influence of the crack angle and the sample position angle. Finally, when the surface is polish, the crack angle and the sample position angle does not have any influence.

  • 91.
    Zhang, Cheng
    University West, Department of Engineering Science, Division of Automation Systems.
    Robotic 3D friction stir welding: T-butt joint2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This Master Thesis was performed in terms of robotic three dimensional friction stir welding with T-butt joint. Friction stir welding (FSW) is a solid state welding method that achieves the weld temperature by friction of a rotating non-consumable tool with the workpiece. Science and technology fast developing requires for higher seam quality and more complex welding joint geometry like 3D welds. In order to acquire high productivity, capacity and flexibility with acceptable cost, robotic FSW solution have been proposed. Instead of the standard FSW machine, using a robot to perform complicated welds such as, three-dimensional.

    In this report, a solution for weld a 3D T-butt joint, which located in an aluminium cylinder with 1.5 mm thickness using a robot, was developed. Moreover, two new paths were investigated in order to avoid the use of two welds to perform this type of joint. The paths were tested on 2D and on 3D (with a 5050 curvature radius) geometries. Both paths had good results. What is more, the parameter developing methods of FSW process, which is composed of necessary parameter setting, positional compensation was introduced. Specially,the study demonstrates how complicate geometry can be welded using a robot. Also,it shows that TWT temperature control is able to acquire high quality 3D welds. In addition, an analysis of the 2D welding and 3D welding was performed, which exposed that, keeping exactly the same welding conditions, higher lateral forces on the tool were found during 3D welding. Basis on the special case in this paper, when the tool goes like "climbing" the sample, the suffering force of tool decreasing with increasing the height(Z position); nevertheless, when the tool goes like "downhill", the suffering force of tool decreasing with decreasing the height (Z position). What is more, in 2D weld, increasing the downforce (Fz) results increasing the lateral forces which can be Fx and/or Fy.

    Finally, the future works suggestions were presented in terms of (1) performing the new paths into a real cylinder, (2) performing tensile test on the paths and comparing it with conventional path which weld twice, (3) researching how the downforce (Fz) influence the Fx and Fy during welding of different 3D geometries, (4) how the cooling rate of backing bar influence the seam quality when it is use the same welding parameters and (5) the effect of performing welds in the same welding temperature achieved with different combination of the tool rotational speed and downforce on the material properties

  • 92.
    Zhang, Xiaoxiao
    University West, Department of Engineering Science, Division of Automation Systems.
    A discussion of methods and strategyfor spot welding localization calibration2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Spot welding is one of the most important welding procedures. Robots are used to perform the welding operation in dangerous and high temperature environment. This technology is to a large extent used in automotive industry to join plates. Specifically, in this work the joining of two plates of a car door is studied for the purpose of making it possible to decrease folded size and thereby materials used and as a result reduce weight of the product. There are many factors adding to uncertainty from the physical world such as noise of the welding machine, weld process or the signals, which all add up related to tolerances in control of the welding process The task of the research in this study is to control spot welding process in order to reduce tolerances and the plate folded size. A sensor system was developed and is described in this report. Universal methods based on laser scanner and cameras are introduced and the advantages and disadvantages of these are discussed. An optimized method based on universal methods with a strategy to meet the timing demands is developed. Experiments are performed to test the methods with ABB robot. The whole sensor system including the communication is built up and the algorithms are executed by programs.     The accuracy of the camera based method is tested in experiments. The result is promising and indicate feasible methods and strategy to locate the spot welding location during operation and thereby make it possible to achieve better welding quality with minimized increasing in cycle time.     Future work should be directed towards to choose a proper laser scanner and to create better mathematical model for the strategy in order to implement this in a real production environment.

  • 93.
    Zhang, Ye
    University West, Department of Engineering Science, Division of Automation Systems.
    Simulation of a production line in Robot Studio: Modelling and simulation2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    With the development of science and technology, production system in modern factories is more complex than it used to be. In order to cut unnecessary loss and protect operators from failure, simulation plays an essential role on testing production lines. In this thesis work, the model of production lines, located in Production Technology Centre (PTC) of University West were built with NX, Autodesk Inventor and simulated with Robot studio. And the production line includes three robot cells (milling machine work cell, turning machine work cell and conveyance work cell, respectively), a gantry robot and some auxiliary equipment, i.e. tables, computers, human task console. Signals were added to make sure the model could work as reality.

    Different measurement methods were used in order to locate production line components at right positions due to their importance to the accuracy of simulation. Measurement methods were also compared with each other to show the error. For instance, the error of CAD models, measurement, and the distance error among equipment, etc.

  • 94.
    Åstrand, Erik
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Lindgren, Eric
    Improved fatigue properties of welded box beams by tailored welding procedures for high penetration fillet weldsIn: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024Article in journal (Other academic)
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