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  • 1. Batungwanayo, Guillaume
    et al.
    Runnemalm, Anna
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Weld Joint Tracking System in an Automatic Inspection Cell by Using Emissivity Variation2014Inngår i: Proceedings of the 6th International Swedish Production Symposium 2014 / [ed] Stahre, Johan, Johansson, Björn & Björkman, Mats, 2014, s. 1-7Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Thermography has proven to be a suitable nondestructive testing method for automatic crack inspection of welds. However automatic weld inspection raises challenges. E.g. the position of the weld might not be exactly as the predefined weld seam, and a weld joint tracking system is needed. To reduce the number of equipment used, a solution is presented in this papers. The infrared camera in the thermography system is a carrier of information of the weld path. This is used for the weld joint tracking system. It is shown that the weld joint tracker is fast enough for an on-line automatic inspection.

  • 2.
    Danielsson, Fredrik
    et al.
    Högskolan Väst, Institutionen för teknik (HTU).
    Ericsson, Mikael
    Högskolan Väst, Institutionen för teknik (HTU).
    Computer Aided Robotics combined with a Finite Element Analysis for Process Simulation of Welding2004Inngår i: 35th International Symposium on Robotics, ISR 2004: Paris, mars 2004, Paris: International Federation of Robotics , 2004Konferansepaper (Fagfellevurdert)
  • 3.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Simulation fo Robot Paths and Heat Effects in Welding2006Doktoravhandling, med artikler (Annet vitenskapelig)
  • 4.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för teknik (HTU).
    Simulation of robotic TIG-welding2003Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 5.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap. Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik.
    Berglund, D.
    Nylén, Per
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap. Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik.
    Three Dimensional Simulation of Robot path, Heat Transfer and Residual Stresses of a TIG-welded Part with Complex Geometry2002Inngår i: Trends in Welding Research: Proceedings of the 6th International Conference: Phoenix, AZ, 15-19 April, 2002, 2002, s. 973-978Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In this paper a system is presented that combines a robot off-line programming software with a finite element model that predicts temperature-time histories and residual stress distributions. The objective is to develop a tool for the engineer where robot trajectories and welding process parameters can be optimized on parts with complex geometry. The system was evaluated on a stainless steel gas turbine component. Robot weld paths were defined off-line and automatically downloaded to the finite element program, where transient temperatures and residual stresses were predicted. Temperature dependent properties and phase change, were included in the analysis. Assumptions and principles behind the modeling techniques are presented together with predicted temperature histories, residual stresses, and fixture forces.

  • 6.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik.
    Bolmsjö, Gunnar
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Nylén, Per
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Three-dimensional simulation of robot path and heat transfer of a TIG-welded part with complex geometry2002Inngår i: 11th International Conferences on Computer Technology in Welding: Colombus, Ohio December 6-7, 2001, 2002, s. 309-316Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The application of commercial software (OLP) packages for robot simulation, and programming, use interactive computer graphics, provide powerful tools for creating welding paths off-line. By the use of such software, problems of robot reach, accessibility, collision and timing can be eliminated during the planning stage. This paper describes how such software can be integrated with a numerical model that predicts temperature-time histories in the solid material. The objective of this integration is to develop a tool for the engineer where robot trajectories and process parameters can be optimized on parts with complex geometry. Such a tool would decrease the number of weld trials, increase productivity and reduce costs. Assumptions and principles behind the modeling techniques are presented together with experimental evaluation of the correlation between modeled and measured temperatures.

  • 7.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Henriksson, P.
    Non-contact Temperature Measurements using an Infrared Camera in Aerospace Welding Applications2002Inngår i: 6th International Conference on Trends in Welding Research: Phoenix, AZ; 15-19 April 2002, Materials Park: ASM International , 2002, s. 930-935Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes the application of infrared (IR) thermal imaging and temperature measurements in welding applications, both on single plane plates and on an aero engine turbine component with complex geometry. Temperature profiles were measured on the plates using thermocouples (T/C) in combination with an IR camera system, and the results were compared. The IR camera was used both in line scan mode (270 Hz scan frequency) and in full frame mode (1 Hz frame rate). Different methods of surface treatments have been tested to handle the problem of the surface emissivity variations due to oxidation during welding. Results from measurements using thermocouples and IR camera is presented in the paper as well as temperature measurements using the IR camera on an turbine exhaust case (TEC) engine component.

  • 8.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Holmblad, Lars
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Almhage, Lisa
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Brochmann, Johanne
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Co-op-modellen – ökad motivation, genomströmning och anställningsbarhet hos studenterna2011Inngår i: 3:e UTVECKLINGSKONFERENSEN FÖR SVERIGES INGENJÖRSUTBILDNINGAR 30 NOVEMBER – 1 DECEMBER 2011 PÅ TEKNISKA HÖGSKOLAN VID LINKÖPINGS UNIVERSITET / [ed] Svante Gunnarsson, Linköping: Linköpings Universitet , 2011, s. 90-93Konferansepaper (Fagfellevurdert)
    Abstract [sv]

    Den här artikeln beskriver ett mycket framgångsrikt utbildningskoncept som genomförs på Högskolan Väst, främst på ingenjörsutbildningarna maskin och elkraft, som ger en ökad samverkan mellan högskola och omkringliggande samhälle. Konceptet bygger på en amerikansk modell som heter ”Cooperative Education” (Co-op). I Co-oputbildningen varvas teoriperioder med betalda arbetsperioder ute på olika företag och organisationer. Genom en väl planerad integration mellan teoriperioderna och arbetsperioderna förlängs utbildningen i genomsnitt med ca 6 månader men studenten har efter erlagd examen ca 1 års arbetslivserfarenhet. För att sköta kontakterna med de olika företagen finns Co-opkoordinatorer anställda på högskolan. Dessa har till uppgift att sköter den grundläggande kontakten med respektive företag. Studenterna anställs av företagen via ett normalt anställningsförfarande och de har lön enligt företagets kollektivavtal. Företagens organisation och arbetssätt integreras naturligt i utbildningen genom Co-opmodellen då studenten deltar i företagets verksamhet. Detta ger studenten en direkt inblick i arbetslivets villkor och en för Co-opmodellen karaktäristisk självgående förmåga hos studenterna utvecklas.

    Under arbetsperioden besöks studenten och företaget av Co-opkoordinatorn. Under detta besök diskuteras bl.a. arbetsinnehåll, utbildning och framtida kunskapsbehov i företaget. Företagens önskemål fångas upp och integreras på ett bra sätt i utbildningen. Exempel på bra samverkan är gästlärare från företagen. Gästlärare har funnits med sen starten av högskolans ingenjörsutbildningar 1990 och andelen kurser med en eller flera gästföreläsare har ökat genom åren. Den främsta samarbetspartnern på elkraftprogrammet är Vattenfall, men också Preemraff och Trollhättan Energi finns representerade.

    Konkreta resultat av utbildningskonceptet är att studenterna blir mer studiemotiverade vilket ger en ökad genomströmning av godkända studenter på programmen jämfört med studenter som inte följer Co-opmodellen. Ett annat resultat är att Co-opstudenterna har en mycket högre anställningsbarhet jämfört med en vanlig student som har läst samma utbildning.

  • 9.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Nylén, Per
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    A look at the optimization of robot welding speed based on process modelling2007Inngår i: Welding Journal, ISSN 0043-2296, Vol. 86, nr 8, s. 238-244Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Simulation tools to search for optimal process parameters are of great interest to reduce the number of experiments and thereby reduce cost and production time. In this paper, robot simulation has been used in combination with finite element simulations to optimize robot speed in order to minimize distortion while keeping complete joint penetration. In an earlier work performed by the authors, a finite element model was developed to predict heat transfer and residual stresses of parts with complex shapes. An interface between a robot simulation model and a finite element analysis model was also constructed. In this paper, an iterative method for robot speed optimization has been developed using MATLAB. The algorithm is designed to maintain complete joint penetration while maximizing productivity by utilizing the fastest weld speed. The method makes it possible to optimize the heat input to the component and thereby minimize component deformation for parts with complex shapes. The system was evaluated on stainless steel plates with varying thicknesses. Robot weld paths were defined off line and automatically downloaded to the finite element software where the optimization was performed. Simulations and experimental validations are presented.

  • 10.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Nylén, Per
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Berglund, D.
    Ling-Peng, R.
    Three dimensional simulation of robot path, heat transfer and residual stresses of a welded part with complex geometry2005Inngår i: International jourrnal for the joining of materials, ISSN 0905-6866, Vol. 17, nr 2, s. 42-51Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article a simulation system is presented that combines computer aided robotics software used to define the welding operation, with a finite element model that predicts temperature-time histories and residual stress distributions for welding applications. The objective is to develop a tool for engineering processes in which robot trajectories and welding process parameters can be optimized off-line on parts with complex geometries. The system was evaluated on a stainless steel gas turbine component. Temperature dependent properties and phase change were included in the analysis. The turbine component was welded using an in-house TIG welding cell. The assumptions and principles that underpin the modeling techniques are presented together with predicted temperature histories, residual stresses, and fixture forces. Predicted residual stresses were compared with neutron diffraction measurements.

  • 11.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Nylén, Per
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Danielsson, Fredrik
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Carlsson, Henrik
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap.
    Off-line programming of robots for metal deposition2005Inngår i: Trends in welding research: Proceedings of the 7th international conference, May 16-20. Pine Mountain, Georgia, 2005, s. 629-634Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Metal Deposition (MD) is a rapid prototyping technique to build parts by depositing metal in a required fashion. When a complex-shaped part is to be built, a simulation tool is needed to define robot trajectories. Three different simulation-based methods for robot trajectory generation are introduced and compared in this study. The methods are; reversed milling, adapted rapid prototyping and application programming in a computer aided robotics software. All methods were shown capable of creating robot paths for complex shapes, with the CAR software approach being the most flexible. Using this method, the geometry to be built is automatically sliced into layers and a robot path is automatically generated. The method was tentatively evaluated and appears to provide a powerful technique in the design and optimisation of robot paths for MD. Experiments showed that it is possible to manufacture fully dense parts using an Nd-Yag laser.

     

  • 12.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Ryberg, Anders
    Nilsson, Jim
    Christiansson, Anna-Karin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automation och datateknik.
    Lennartson, Bengt
    Chalmers.
    Off-Line Simulation of Advanced Stereo Vision Welding Applications2010Inngår i: Machine Vision and Applications, ISSN 0932-8092, E-ISSN 1432-1769Artikkel i tidsskrift (Fagfellevurdert)
  • 13.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Zhang, Xiaoxiao
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Christiansson, Anna-Karin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Virtual Commissioning of Machine Vision Applications in Aero Engine Manufacturing2018Inngår i: Proceedings of The 15th International Conference on Control,Automation, Robotics and Vision, November 18-21, 2018, 2018, s. 1947-1952, artikkel-id 0293Konferansepaper (Fagfellevurdert)
    Abstract [en]

    New aero engine design puts new demands on the manufacturing methods with increased automation level. Therefore, the use of vision sensors for control and guiding of industrial robots is being increasingly used. In such system, it is need to customise the machine vision system with real components in the real environment which is normally done close to the start-up of the production. This paper addresses a new concept for designing, programming, analysing, testing and verifying a machine vision application early in the design phase, called Virtual Machine Vision. It is based on a robot simulation software where the real machine vision application is simulated before the implementation in the production line. To verify the Virtual Machine Vision concept an advanced stereo vision application was used. Using two captured images from the robot simulated environment, camera calibration, image analysis and stereo vision algorithms are applied to determine a desired welding joint. The information of the weld joint, i.e. robot position and orientation for the weld path, are sent from the machine vision system to the robot control system in the simulation environment and the weld path is updated. The validation of the Virtual Machine Vision concept using the stereo vision application is promising for industrial use, and it is emphasised that the same programs are used in the virtual and real word.

  • 14.
    Eriksson, Kristina M.
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Chirumalla, Koteshwar
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    A novel blended learning course developed jointly between three universities to address competence development of professionals in digitalized manufacturing2019Inngår i: VILÄR 5-6 december 2019, University West, Trollhättan: Abstracts / [ed] Kristina Johansson, Trollhättan: University West , 2019, s. 6-7Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    New competences and knowledge needs arises as manufacturing industry evolves and becomes increasingly digitalized. Facing this transformation, one of the challenges is the continuous and growing need for novel initiatives for competence development.The case portrayed here stems from a Swedish cross-university project aiming to jointly develop and offer courses for competence development of professionals in the manufacturing and IT sectors. The ambition is to increase the impact of the universities' respective efforts of meeting industry competence needs, where the continuous digital transformation entails that employees must develop or even change their qualifications.

    The case outlined focus co-production of a joint course package, at master level, between three universities and their respective company networks. Participating universities have long traditions in working closely with companies in research and education, where approaches for co-production have evolved over time. We make use of our joint understanding of the manufacturing industry's specific competence needs and our experiences of sustainable course formats for participants working full time.The joint course covers aspects of a manufacturing company on three levels: plant level i.e. material and production flows, cell level e.g. robotic simulation and visualisation, and system level i.e. data acquisition and monitoring through sensors. Each university is developing a course module of 2.5 ECTS, addressing a level respectively of their specialist competence. Participants are to complete assignments for each course module, i.e. for all three manufacturing levels, where the previous assignment provides an input to the next level, enabling the participants to encompass a holistic view of a manufacturing system. Participants need to combine study and work and at the same time they wish to extend their network, hence we are adopting a blended learning approach, where virtual labs and web conferences are mixed with physical meetings.A variety of challenges arise when designing such novel approaches: combining company networks, course design including online learning, planning of physical course meetings,

    joint promotion, common admission and validation process, financial models and more. However, engaging in partnerships with industry for knowledge transformation and development has the potential to become rewarding for all parties.

  • 15.
    Keyvani, Ali
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro, lantmäteri och naturvetenskap. Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Johansson, Henrik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro, lantmäteri och naturvetenskap.
    Motion synthesizer platform for moving manikins2012Inngår i: 2012 AHFE International Conference 21-25 July 2012 Hilton San Francisco, Union Square, California: Conference proceedings, AHFE , 2012, s. 545-554Konferansepaper (Fagfellevurdert)
  • 16.
    Keyvani, Ali
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro, lantmäteri och naturvetenskap. Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Johansson, Henrik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro, lantmäteri och naturvetenskap.
    Lämkull, Dan
    Volvo Car Corporation.
    Örtengren, Roland
    Chalmers.
    Schema for Motion Capture Data Management2011Inngår i: Lecture Notes in Computer Science. 3rd International Conference on Digital Human Modeling, ICDHM 2011: Orlando, 9-14 July 2011, 2011, s. 99-108Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A unified database platform capable of storing both motion captured data and information about these motions (metadata) is described. The platform stores large motion captured data in order to be used by different applications for searching, comparing, analyzing and updating existing motions. The platform is intended to be used to choose a realistic motion in simulation of production lines. It is capable of supporting and handling different motion formats, various skeleton types and distinctive body regions in a uniform data model. Extended annotating system is also introduced to mark the captured data not only in the time domain (temporal) but also on different body regions (spatial). To utilize the platform, sample tests are performed to prove the functionality. Several motion captured data is uploaded to the database while MATLAB is used to access the data, ergonomically analyze the motions based on OWAS standard, and add the results to the database by automatic tagging of the postures.

  • 17.
    Runnemalm, Anna
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Liu, Tongwein
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automation och datateknik.
    Appelgren, Anders
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automation och datateknik.
    Influence of Vibration Induced Disturbances in an Automatic Inspection Cell2013Inngår i: Robotics in Smart Manufacturing / [ed] Pedro Neto,António Paulo Moreira, 2013, s. 191-202Konferansepaper (Fagfellevurdert)
    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.

  • 18.
    Ryberg, Anders
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Christiansson, Anna-Karin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Eriksson, Kenneth
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för lantmäteriteknik och matematik.
    Nilsson, Jim
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Larsson, Matthias
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Stereo vision for path correction in off-line programmed robot welding2010Inngår i: Proceedings of the IEEE International Conference on Industrial Technology, 2010, s. 1700-1705Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper describes a versatile machine vision system for correcting off-line programmed nominal robot trajectories for advanced welding. Weld trajectory corrections are needed due to slight variations in weld joints. Such variations occur naturally because of varying tolerances in parts and to heat induced deformations during earlier weld sequences. The developed system uses one camera and a weld tool mounted on the robot hand. As a first step, the whole system, including the camera, is calibrated. Then the system takes images of the weld joint from different positions and orientations, and determines the weld joint geometry in 3D using a stereo vision algorithm and a novel camera model. The weld trajectory is then updated in the robot control system, and weld operation is performed. These steps are repeated for all weld sequences of the work piece. The strategy has successfully been demonstrated for a standard industrial welding robot and a standard FireWire CMOS camera. The maximum deviation of the trajectory found by the system compared to a reference (coordinate measuring machine) is 0.7 mm and the mean deviation is 0.23 mm. Thus, the system shows high potential for industrial implementation. ©2010 IEEE.

  • 19.
    Ryberg, Anders
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Lennartson, Bengt
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Christiansson, Anna-Karin
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Asplund, Lars
    Mälardalen University.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Analysis and evaluation of a general camera model2011Inngår i: Computer Vision and Image Understanding, ISSN 1077-3142, E-ISSN 1090-235X, Vol. 115, nr 11, s. 1503-1515Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A versatile General Camera Model, GCM, has been developed, and is described in detail. The model is general in the sense that it can capture both fisheye and conventional as well as catadioptric cameras in a unified framework. The camera model includes efficient handling of non-central cameras as well as compensations for decentring distortion. A novel way of analysing radial distortion functions of camera models leads to a straightforward improvement of conventional models with respect to generality, accuracy and simplicity. Different camera models are experimentally compared for two cameras with conventional and fisheye lenses, and the results show that the overall performance is favourable for the GCM.

  • 20.
    Sikström, Fredrik
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Integration of finite element analysis and computer aided robotics for advanced programming of robotized welding2009Inngår i: ASM Proceedings of the International Conference: Trends in Welding Research / [ed] S.A. David, T. DebRoy, J.N. DuPont, T. Koseki, and H.B. Smartt, ASM International, 2009, s. 454-460Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes a promising approach where finite element analysis is combined with computer aided robotics in off-line programming of advanced robotized welding. Finite element analysis is used to find an optimized weld power signal based on weld trajectories obtained from computer aided robotic simulations. The weld power signal is calculated by applying feedback control in the finite element simulation. This optimization ensures a full penetration weld while the total specific thermal energy input is minimized in order to mitigate unwanted residual stress and distortion. The objective with this approach is to support the design of robotized welding and significantly reduce the number of costly trials in physical implementations. The relevance of this paper is a useful method for off-line optimization of robot trajectories and varying process parameters.

  • 21.
    Sikström, Fredrik
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Christiansson, Anna-Karin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro- och automationsteknik.
    Niklasson, Kjell
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för process- och produktutveckling.
    Tools for simulation based fixture design to reduce deformation in advanced fusion welding2008Inngår i: Intelligent Robotics and ApplicationsLecture Notes in Computer Science Volume 5315,  2008: First International Conference, ICIRA 2008 Wuhan, China, October 15-17, 2008 Proceedings, Part II / [ed] Youlun Xioun, Springer, 2008, Vol. 5315 LNAI, nr PART 2, s. 398-407Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The traditional fusion welding and fixture simulations are performed using advanced finite element simulation tools, commonly used are e.g. MSC.Marc, ANSYS, ABACUS and COMSOL Multiphysics. These simulations are made one at a time and separately due to heavy calculation load for each case. Such an approach does not give a full description of the integrated work piece and fixture behaviour. We propose a strategy to decrease the computational time and solve the problem accurately enough for industrial needs. Focus of the simulation result is on residual deformation. The work piece is a simplified component composed by metal sheets, and rigid and loose clamping was investigated. Simulation results give the size of forces and deformations in the clamped edge. Deformation measurements are performed using 3D-scanning of the work piece after cooling and released from fixture, same situation as in the FE-simulations. The proposed strategy has shown to be useful and is industrially competitive due to reduced engineering manpower, computation time, and need for practical experiments. The strategy is to use full off-line programming where computer aided robotics for weld sequencies is integrated with finite element modelling in order to obtain weld parameters and fixture design.

  • 22.
    Sikström, Fredrik
    et al.
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för elektro- och lantmäteri.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för elektro- och lantmäteri.
    Nylén, Per
    Högskolan Väst, Institutionen för teknik, matematik och datavetenskap, Avd för maskinteknik.
    Christiansson, Anna-Karin
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    3D-Scanning for Weld Distortion Measuring2006Inngår i: Instrumentation and Measurement Technology Conference, 2006. IMTC 2006. Proceedings of the IEEE, IEEE conference proceedings, 2006, s. 2132-2137Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Optical three dimensional scanning for weld distortion measurements have been performed for validation, inspection, general visualization and documentation of a robotized welding process. The planning, preparing and processing of the weld is done in a simulation-based concept where computer aided robotics software simulations are integrated with finite element analysis simulations with the objective to reduce global geometrical deformation during welding. The off-line programmed robot paths were used as an input for finite element calculations of temperature fields and distortion in the work piece. In order to validate the finite element model 3D-scannings have been performed before and after every single welding sequence. This paper describes a validation experiment with non-contact measurements of weld distortion and discusses limitations in optical 3D-scanning techniques used for this purpose

  • 23.
    Wärmefjord, Kristina
    et al.
    Chalmers University of Technology, Dept. of Product and Production Development, SE-412 96 Gothenburg, Sweden.
    Söderberg, Rikard
    Chalmers University of Technology, Dept. of Product and Production Development, SE-412 96 Gothenburg, Sweden.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Appelgren, Anders
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Lundbäck, Andreas
    Luleå University of Technology, Dept. of Engineering Sciences and Mathematics, SE-971 87 Luleå, Sweden.
    Lööf, Johan
    GKN Aerospace,Engine Systems, SE-461 81 Trollhättan, Sweden .
    Lindkvist, Lars
    Chalmers University of Technology, Dept. of Product and Production Development, SE-412 96 Gothenburg, Sweden.
    Svensson, Hans-Olof
    GKN Aerospace,Engine Systems, SE-461 81 Trollhättan, Sweden .
    Welding of non-nominal geometries: physical tests2016Inngår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 43, s. 136-141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The geometrical quality of a welded assembly is to some extent depending part positions before welding. Here, a design of experiment is set up in order to investigate this relation using physical tests in a controlled environment. Based on the experimental results it can be concluded that the influence of part position before welding is significant for geometrical deviation after welding. Furthermore, a working procedure for a completely virtual geometry assurance process for welded assemblies is outlined. In this process, part variations, assembly fixture variations and welding induced variations are important inputs when predicting the capability of the final assembly.

1 - 23 of 23
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