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  • 1.
    Adolfsson, Sebastian
    University West, Department of Engineering Science, Division of Production System.
    RatSLAM with Viso2: Implementation of alternative monocular odometer2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this work, a ROS (Robot Operating System) version of Open RatSLAM, [1] [2], was tested with Viso2 [3] as an alternative monocular odometer. A land based rover [4] was used to perform data acquisition and a remote control tool was developed to facilitate this procedure, implemented as ROS nodes on both Ubuntu 16.04 and on Android 7.0.An additional requirement that comes from using Viso2 is the need for camera information together with the image stream, which might require camera calibration. A ROS node to manually add this camera information was made as well as a node to change the generated odometry message from Viso2 to a form that RatSLAM uses. The implemented odometer uses feature tracking to estimate motion, which is fundamentally different to matching intensity profiles which the original method does and can hence be used when different properties of the visual odometry function is desired. From experiments, it was seen that the feature tracking method from Viso2 generated amore robust motion estimate in terms of real world scale and it was also able to better handle environments of varying illumination or that contains large continuous surfaces of the same colour. However, the feature tracking may give slight variations in the generated data upon successive runs due to the random selection of features to track. Since the structure of RatSLAM gives the system ability to make loop closures even with large differences in position, an alternative odometry does not necessarily give a significant improvement in performance of the system in environments that the original system operates well in. Even though both algorithms show difficulty with estimating fast rotations, especially when the camera view contains areas with few features, the performance improvement in Viso2 together with its ability to better maintain the real-world scale motivates its usefulness. The source code, as well as instructions for installation and usage is public

  • 2.
    Adolfsson, Sebastian
    University West, Department of Engineering Science, Division of Production System.
    RatSLAM with Viso2: Implementation of alternative monocular odometer2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this work, a ROS (Robot Operating System) version of OpenRatSLAM, [1] [2], was tested with Viso2 [3] as an alternative monocular odometer. A land based rover [4] was used to perform data acquisition and a remote control tool was developed to facilitate this procedure, implemented as ROS nodes on both Ubuntu 16.04 and on Android 7.0.  An additional requirement that comes from using Viso2 is the need for camera information together with the image stream, which might require camera calibration. A ROS node to manually add this camera information was made as well as a node to change the generated odometry message from Viso2 to a form that RatSLAM uses. The implemented odometer uses feature tracking to estimate motion, which is fundamentally different to matching intensity profiles which the original method does and can hence be used when different properties of the visual odometry function is desired. From experiments, it was seen that the feature tracking method from Viso2 generated a more robust motion estimate in terms of real world scale and it was also able to better handle environments of varying illumination or that contains large continuous surfaces of the same colour. However, the feature tracking may give slight variations in the generated data upon successive runs due to the random selection of features to track. Since the structure of RatSLAM gives the system ability to make loop closures even with large differences in position, an alternative odometry does not necessarily give a significant improvement in performance of the system in environments that the original system operates well in. Even though both algorithms show difficulty with estimating fast rotations, especially when the camera view contains areas with few features, the performance improvement in Viso2 together with its ability to better maintain the real-world scale motivates its usefulness.  The source code, as well as instructions for installation and usage is public.

  • 3.
    AlNabulsi, Yasan
    University West, Department of Engineering Science, Division of Production System.
    Robot motion control based on 3D mouse tracking2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The manufacturing industry and associated systems are being developed in an increasing manner to cover the market needs, where the manufacturing companies are continuously racing and competing to achieve high productivity rate and better production quality. In this thesis work, an advanced method for motion control of industrial robots has been investigated and implemented. This method is based on motion tracking of a 3DSpaceMouse, which was used to perform movements by the operator. The benefits and disadvantages of this method were discussed in this thesis work. It mainly showed a high accuracy in response to the motion applied by the 3DSpaceMouse, and a great stability regarding the programming environment that was used to build it. The movements applied by the 3DSpaceMouse were successfully captured and stored in variables in the programming platform. The capturing and storing process was successfully created as a package and prepared to be exported for usage by other software. Complete simulation was performed for an industrial robot, and successful communications among the various hardware and software components of this solution were accomplished. This has formed a complete integrated solution that has also included a user-friendly HRI. This HRI made it easy and simple to track the motion control processes and establish connections with the robot controller. Thus, it can be considered a feasible solution for motion control of industrial robots, which can be used by the manufacturing companies. Several tests and verification processes were carried out to obtain accepted results and to succeed in implementing a working model. Some errors and unexpected events have appeared during the work, which required handling in order to achieve a working integrated system.

  • 4.
    Asad, Ahmed
    et al.
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Sallander, Rikard
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Balansering och tidsoptimering av materialsatsning till F12-monteringen på Parker PMDE Trollhättan2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In industries, the management tools of Lean Production are used to develop and streamline operations in a way to reduce waste and lead times in all processes. Parker PMDE in Trollhättan manufactures hydraulic machines. Since the 90´s, Parker has pursued business development under the management principles of Lean Production. One of the next steps in Parkers continuous improvement was to explore opportunities to develop a kitting department so that a worker could provide the assembly with the material quickly without surplus resources. In the current situation, there is an imbalance from the kitting station towards the tact times in the assembly station because it takes longer at the kitting station to pick materials for four hydraulic machines, than it takes for the assembly station to consume these kits of materials.The aim of the thesis was to develop suggestions for improvement where a worker could perform the kitting process in less than 16 minutes. The interim objectives were to do a survey of the times and activities within the kitting process. The boundaries of the project was not to examine processes outside the kitting station. The project was designed according to DMAIC methodology, which is a project model for fact-based problem solving and clear structure. The methods used in the data collection were observation and analysis of video footage applying the software called AviX Method. Video recordings were categorized as different activities in the kitting process such as transport, picking, scanner time, pre-assembly and uncategorized time. Activities that were time consuming and did not add value to the process were identified. These data measures were the basis for the solution proposals.Based on these results and using brainstorming, solution proposals were generated together with the engineers and material handlers. The solution proposals that met the objective of the project of picking a 4-set of materials in 16 minutes were: Pick by voice, Pick-by-light, Ring Scanner and Relocation of one pre-assembly operation. Pick by voice is considered to be the most appropriate solution for the company since it reduces picking times, scanning times and is a flexible system. Two more proposed solutions were developed that did not meet the objective of the project, but are considered worth investigating further based on Lean Production and ergonomic reasons. These proposed solutions consisted of changing the picking route and the installation of a magnetic lift.

  • 5.
    Bergström, Per
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Luleå, Sweden.
    Fergusson, Michael
    Xtura AB, Kungsbacka, Sweden.
    Folkesson, Patrik
    Xtura AB, Kungsbacka, Sweden.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Production System.
    Ottosson, Mattias
    University West, Department of Engineering Science, Division of Production System.
    Andersson, Alf
    Chalmers University of Technology, Department of Product and Production Development, Gothenburg, Sweden.
    Sjödahl, Mikael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Luleå, Sweden.
    Automatic in-line inspection of shape based on photogrammetry2016In: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings: 25th – 27th of October 2016, Lund: Swedish Production Academy , 2016, 1-9 p.Conference paper (Refereed)
    Abstract [en]

    We are describing a fully automatic in-line shape inspection system for controlling the shape of moving objects on a conveyor belt. The shapes of the objects are measured using a full-field optical shape measurement method based on photogrammetry. The photogrammetry system consists of four cameras, a flash, and a triggering device. When an object to be measured arrives at a given position relative to the system, the flash and cameras are synchronously triggered to capture images of the moving object.From the captured images a point-cloud representing the measured shape is created. The point-cloud is then aligned to a CAD-model, which defines the nominal shape of the measured object, using a best-fit method and a feature-based alignment method. Deviations between the point-cloud and the CAD-model are computed giving the output of the inspection process. The computational time to create a point-cloud from the captured images is about 30 seconds and the computational time for the comparison with the CAD-model is about ten milliseconds. We report on recent progress with the shape inspection system.

  • 6.
    Bolmsjö, Gunnar
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Bennulf, Mattias
    University West, Department of Engineering Science, Division of Production System.
    Zhang, Xiaoxiao
    University West, Department of Engineering Science, Division of Production System.
    Safety System for Industrial Robots to Support Collaboration2016In: Advances in Ergonomics of Manufacturing: Managing the Enterprise of the Future. Proceedings of the AHFE 2016 International Conference on Human Aspects of Advanced Manufacturing, July 27-31, 2016, Walt Disney World®, Florida, USA / [ed] Christopher Schlick, Stefan Trzcieliński, Springer International Publishing , 2016, 253-265 p.Chapter in book (Refereed)
    Abstract [en]

    The ongoing trend towards manufacturing of customized products generates an increased demand on highly efficient work methods to manage product variants through flexible automation. Adopting robots for automation is not always feasible in low batch production. However, the combination of humans together with robots performing tasks in collaboration provides a complementary mix of skill and creativity of humans, and precision and strength of robots which support flexible production in small series down to one-off production. Through this, collaboration can be used with implications on reconfiguration and production. In this paper, the focus and study is on designing safety for efficient collaboration operator—robot in selected work task scenarios. The recently published ISO/TS 15066:2016 describing collaboration between operator and robot is in this context an important document for development and implementation of robotic systems designed for collaboration between operator and robot.

  • 7.
    Broberg, Patrik
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Production System.
    Analysis algorithm for surface crack detection by thermography with UV light excitation2016In: Quantitative InfraRed Thermography 2016: Abstracts / [ed] Kaczmarek, M. & Bujnowski, A., Gdańsk, Poland: Publishing Gdańsk University of Technology , 2016, 144-149 p.Conference paper (Refereed)
    Abstract [en]

    Surface crack defects can be detected by IR thermograpgy due to the high absorption of energy within the crack cavity. It is often difficult to detect the defect in the raw data, since the signal easily drowns in the background. It is therefore important to have good analysis algorithms that can reduce the background and enhance the defect. Here an analysis algorithm is presented which significantly increases the signal to noise ratio of the defects and reduces the image sequence from the camera to one image.

  • 8.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Production System. TWI Ltd, Cambridge, UK.
    Martin, Jonathan
    TWI Ltd, Cambridge, UK.
    Wei, Sam
    TWI Ltd, Cambridge, UK.
    Robotic Stationary Shoulder FSW: benefits and limitations2016In: Conference proceedings of the 11th International Symposium on Friction Stir Welding, 2016Conference paper (Refereed)
  • 9.
    Emanuelsson, Viktor
    et al.
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Wahlberg, Christoffer
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Omkonstruktion av fixtur avsedd för manuell svetskontroll av turbinmotorstativ2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor's thesis treats the production of a fixture for manual physical and visual weld inspection of an aircraft engine stand, 30k TEC (Turbine Exhaust Case), for GKN Aerospace in Trollhättan. The main problem is that the inspection of 30k TEC had not previously occurred to the extent that is current today. The purpose was to facilitate the inspection staff's work situation and to determine whether it is possible to use parts of a fixture adapted to a different aircraft engine stand.The work is based, for the project, on relevant methods that includes data collection, inter¬pretation of collected data, concept generation and concept selection. Interested parties were identified with their respective demands on the fixture and the environment. Concept proposals were generated along with interviews and observations of similar fixtures. The concept proposals went through a concept selection process, which resulted in a final concept.The final concept allows motorized rotation of the aircraft engine stand and it is equipped with supports which prevents the aircraft engine stand to fall off the fixture. The support prevents the turbine exhaust case from falling off during the inspection, which could result in both material damage to the aircraft engine stand and equipment as well as physical damage to the inspection staff. Due to the possibility to rotate the aircraft engine stand with a motor the fixture is classified as a machine and must therefore be CE marked by the manufacturer. The work therefore includes in-depth knowledge in the Machinery Directive and the requirements for CE marking of machines. To meet the ergonomic aspects for the inspection staff, guidelines for ergonomic work.The report presents the final concept and its included components. The employer's work deliverables consists of order documents ready to be sent to the manufacturer of the fix-ture containing drawings and parts lists. Both manufacturers and inspection staff have shown a positive attitude towards the outcome.

  • 10.
    Glorieux, Emile
    University West, Department of Engineering Science, Division of Production System.
    Multi-Robot Motion Planning Optimisation for Handling Sheet Metal Parts2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Motion planning for robot operations is concerned with path planning and trajectory generation. In multi-robot systems, i.e. with multiple robots operating simultaneously in a shared workspace, the motion planning also needs to coordinate the robots' motions to avoid collisions between them. The multi-robot coordination decides the cycle-time for the planned paths and trajectories since it determines to which extend the operations can take place simultaneously without colliding. To obtain the quickest cycle-time, there needs to bean optimal balance between, on the one hand short paths and fast trajectories, and on the other hand possibly longer paths and slower trajectories to allow that the operations take place simultaneously in the shared workspace. Due to the inter-dependencies, it becomes necessary to consider the path planning, trajectory generation and multi-robot coordination together as one optimisation problem in order to find this optimal balance.This thesis focusses on optimising the motion planning for multi-robot material handling systems of sheet metal parts. A methodology to model the relevant aspects of this motion planning problem together as one multi-disciplinary optimisation problem for Simulation based Optimisation (SBO) is proposed. The identified relevant aspects include path planning,trajectory generation, multi-robot coordination, collision-avoidance, motion smoothness, end-effectors' holding force, cycle-time, robot wear, energy efficiency, part deformations, induced stresses in the part, and end-effectors' design. The cycle-time is not always the (only) objective since it is sometimes equally/more important to minimise robot wear, energy consumption, and/or part deformations. Different scenarios for these other objectives are therefore also investigated. Specialised single- and multi-objective algorithms are proposed for optimising the motion planning of these multi-robot systems. This thesis also investigates how to optimise the velocity and acceleration profiles of the coordinated trajectories for multi-robot material handling of sheet metal parts. Another modelling methodology is proposed that is based on a novel mathematical model that parametrises the velocity and acceleration profiles of the trajectories, while including the relevant aspects of the motion planning problem excluding the path planning since the paths are now predefined.This enables generating optimised trajectories that have tailored velocity and acceleration profiles for the specific material handling operations in order to minimise the cycle-time,energy consumption, or deformations of the handled parts.The proposed methodologies are evaluated in different scenarios. This is done for real world industrial case studies that consider the multi-robot material handling of a multi-stage tandem sheet metal press line, which is used in the automotive industry to produce the cars' body panels. The optimisation results show that significant improvements can be obtained compared to the current industrial practice.

  • 11.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Franciosa, Pasquale
    Warwick Manufacturing Group, University of Warwick, CV4 7AL Coventry, UK.
    Ceglarek, Darek
    Warwick Manufacturing Group, University of Warwick, CV4 7AL Coventry, UK.
    End-effector design optimisation and multi-robot motion planning for handling compliant parts2017In: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, 1-14 p.Article in journal (Refereed)
    Abstract [en]

    The deformation of compliant parts during material handling is a critical issue that can significantly affect the productivity and the parts' dimensional quality. There are multiple relevant aspects to consider when designing end-effectors to handle compliant parts, e.g. motion planning, holding force, part deformations, collisions, etc. This paper focuses on multi-robot material handling systems where the end-effector designs influence the coordination of the robots to prevent that these collide in the shared workspace. A multi-disciplinary methodology for end-effector design optimisation and multi-robot motion planning for material handling of compliant parts is proposed. The novelty is the co-adaptive optimisation of the end-effectors' structure with the robot motion planning to obtain the highest productivity and to avoid excessive part deformations. Based on FEA, the dynamic deformations of the parts are modelled in order to consider these during the collision avoidance between the handled parts and obstacles. The proposed methodology is evaluated for a case study that considers the multi-robot material handling of sheet metal parts in a multi-stage tandem press line. The results show that a substantial improvement in productivity can be achieved (up to 1.9%). These also demonstrate the need and contribution of the proposed methodology.

  • 12.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Parthasarathy, Prithwick
    University West, Department of Engineering Science, Division of Production System.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production System.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production System.
    Energy Consumption Model for 2D-Belt Robots2016In: 7th Swedish Production Symposium Conference proceedings, Lund: SPS16 , 2016, 1-7 p.Conference paper (Refereed)
    Abstract [en]

    Production that incorporates robotics consumes energy and the trend today is to reduce consumed energy not only to lower the cost but also to be a more energy efficient entity. Energy models can be used to predict the energy consumed by robot(s) for optimising the input parameters which determine robot motion and task execution. This paper presents an energy model to predict the energy consumption of 2D-belt robots used for press line tending. Based on the components’ specifications and the trajectory, an estimation of the energy consumption is computed. The capabilities of the proposed energy model to predict the energy consumption during the planning-phase (i.e. before installation), avoiding the need for physical experiments, are demonstrated. This includes predicting potential energy reductions achieved by reducing the weight of the gripper tools. Additionally, it is also shown how to investigate the energy saving achieved by using mechanical brakes when the robot is idle. This effectively illustrates the purpose and usefulness of the proposed energy model.

  • 13.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Riazi, Sarmad
    Department of Signals and Systems, Chalmers University of Technology, S-412 96 Gothenburg, Sweden.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production System. Department of Signals and Systems, Chalmers University of Technology, S-412 96 Gothenburg, Sweden.
    Productivity/energy optimisation of trajectories and coordination for cyclic multi-robot systems2018In: Robotics and Computer-Integrated Manufacturing, ISSN 0736-5845, E-ISSN 1879-2537, Vol. 49, 152-161 p.Article in journal (Refereed)
    Abstract [en]

    The coordination of cyclic multi-robot systems is a critical issue to avoid collisions but also to obtain the shortest cycle-time. This paper presents a novel methodology for trajectory and coordination optimisation of cyclic multi-robot systems. Both velocity tuning and time delays are used to coordinate the robots that operate in close proximity and avoid collisions. The novel element is the non-linear programming optimisation model that directly co-adjusts the multi-robot coordination during the trajectory optimisation, which allows optimising these as one problem. The methodology is demonstrated for productivity/smoothness optimisation, and for energy efficiency optimisation. An experimental validation is done for a real-world case study that considers the multi-robot material handling system of a multi-stage tandem press line. The results show that the productivity optimisation with the methodology is competitive compared to previous research and that substantial improvements can be achieved, e.g. up to 50% smoother trajectories and 14% reduction in energy consumption for the same productivity. This paper addresses the current lack of systematic methodologies for generating optimal coordinated trajectories for cyclic multi-robot systems to improve the productivity, smoothness, and energy efficiency.

  • 14.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production System.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production System.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production System. Department of Signals and Systems, Chalmers University of Technology, S-412 96 Gothenburg, Sweden.
    Constructive cooperative coevolution for large-scale global optimisation2017In: Journal of Heuristics, ISSN 1381-1231, E-ISSN 1572-9397, 1-21 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents the Constructive Cooperative Coevolutionary ( C3C3 ) algorithm, applied to continuous large-scale global optimisation problems. The novelty of C3C3 is that it utilises a multi-start architecture and incorporates the Cooperative Coevolutionary algorithm. The considered optimisation problem is decomposed into subproblems. An embedded optimisation algorithm optimises the subproblems separately while exchanging information to co-adapt the solutions for the subproblems. Further, C3C3 includes a novel constructive heuristic that generates different feasible solutions for the entire problem and thereby expedites the search. In this work, two different versions of C3C3 are evaluated on high-dimensional benchmark problems, including the CEC'2013 test suite for large-scale global optimisation. C3C3 is compared with several state-of-the-art algorithms, which shows that C3C3 is among the most competitive algorithms. C3C3 outperforms the other algorithms for most partially separable functions and overlapping functions. This shows that C3C3 is an effective algorithm for large-scale global optimisation. This paper demonstrates the enhanced performance by using constructive heuristics for generating initial feasible solutions for Cooperative Coevolutionary algorithms in a multi-start framework.

  • 15.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production System.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production System.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production System. Department of Signals and Systems, Chalmers University of Technology,Gothenburg, Sweden.
    Multi-objective constructive cooperative coevolutionary optimization of robotic press-line tending2017In: Engineering optimization (Print), ISSN 0305-215X, E-ISSN 1029-0273, Vol. 49, no 10, 1685-1703 p.Article in journal (Refereed)
    Abstract [en]

    This article investigates multi-objective optimization of the robot trajectories and position-based operation-coordination of complex multi-robot systems, such as press lines, to improve the production rate and obtaining smooth motions to avoid excessive wear of the robots’ components. Different functions for handling the multiple objectives are evaluated on realworld press lines, including both scalarizing single-objective functions and Pareto-based multi-objective functions. Additionally, the Multi-Objective Constructive Cooperative Coevolutionary (moC3) algorithm is proposed, for Pareto-based optimization, which uses a novel constructive initialization of the subpopulations in a co-adaptive fashion. It was found that Paretobased optimization performs better than the scalarizing single-objective functions. Furthermore, moC3 gives substantially better results compared to manual online tuning, as currently used in the industry. Optimizing robot trajectories and operation-coordination of complex multi-robot systems using the proposed method with moC3 significantly improves productivity and reduces maintenance. This article hereby addresses the lack of systematic methods for effectively improving the productivity of press lines.

  • 16.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production System.
    Parthasarathy, Prithwick
    University West, Department of Engineering Science, Division of Production System.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production System.
    An energy model for press line tending robots2016In: ESM'2016, the 2016 European simulation and Modelling Conference: Modelling and Simulation '2016 / [ed] José Evora-Gomez & José Juan Hernandez-Cabrera, Eurosis , 2016, 377-383 p.Conference paper (Refereed)
    Abstract [en]

    Today most industries aim at reducing energy consumption to become sustainable and environment-friendly. The automotive industry, with mass production and large volumes, is one such example. With many robots working round the clock, there is great potential to save energy. In this climate there is a need for robot simulation models that can be used for motion and task execution optimisation and which are aimed lowering energy consumption. This paper presents an energy consumption model for 2D-belt robots for press line tending in the automotive sector. The energy model is generic for 2D-belt robots and is entirely based on component specifications (e.g., dimensions, masses, inertia). An implementation and validation against a real 2D-belt tending robot used in the automotive industry is performed and presented. The purpose and usefulness of the energy model is also demonstrated by two application cases; the investigation of potential energy reductions achieved by reducing the weight of gripper tools, and by using mechanical brakes when the robot is idle.

  • 17.
    Gustavsson Christiernin, Linn
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Augustsson, Svante
    University West, Department of Engineering Science, Division of Production System.
    Interacting with Industrial Robots: A Motion-based Interface2016In: AVI '16 Proceedings of the International Working Conference on Advanced Visual Interfaces / [ed] Paolo Buono, Rosa Lanzilotti, Maristella Matera, New York: ACM Digital Library, 2016, 310-311 p.Conference paper (Refereed)
    Abstract [en]

    Collaborative industrial robot cells are becoming more and more interesting for industry through the new Industrie 4.0 initiative. In this paper we report early work on motion-based interaction with industrial robots. Human motion is tracked by a Kinect camera and translated into robot code. A group of tests subjects are asked to interact with the system and their activities are observed. Lessons learned on interaction challenges in a robot cell are reported.

  • 18.
    Gustavsson Christiernin, Linn
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Hartler, Johan
    Department of Shipping and Marine Technology Chalmers Technical University Gothenburg, Sweden.
    Multi-Layered Design and Game-Based Learning as a Pedagogical Concept: How to develop proper behavior in ARPA simulator training2016Conference paper (Refereed)
    Abstract [en]

    To become a professional master mariner one has to develop many different skills and have an understanding of how to act in different situations on the bridge. Within the master mariner program at Chalmers University of Technology, Sweden, simulation technologies are used to evolve pertinent skills within the educational program. A challenge with using a full scale simulator from the outset of the program is to get the students to develop both professional competencies and internalize tacit knowledge in the navigation of a ship when the interface of the simulator itself is quite demanding. By using an adaptive Multi-Layered Design approach in combination with game based learning, this paper proposes how to guide the student through a more summative learning process. The main idea is to grant limited access to what the students can do with some functions, and gradually turn on more functionality in order to develop certain experienced behaviors to get them to understand the logical approach behind selections and to make them think through why and when they should do things.

  • 19.
    Hattinger, Monika
    University West, Department of Engineering Science, Division of Production System.
    Sociomateriality and design – How do we un-pack technology for knowing in practice?: Research in Progress/Workshop2016Conference paper (Other academic)
  • 20.
    Hattinger, Monika
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Norström, Livia
    University West, Department of Economics and IT, Division of Media and Design.
    Unpacking Social Media to explore professionals work practice2016In: Proceedings of IRIS39, Information Systems Research Seminar in Scandinavia, Ljungskile, August 7-10, 2016 / [ed] Pareto, Lena, Svensson, Lars, Lundin, Johan, Lundh Snis, Ulrika Lundh Snis, 2016, 1-14 p.Conference paper (Other academic)
    Abstract [en]

    Organizations are inspired by the massive social media use in the private domain and try to filter interactions and knowledge sharing in socialmedia also for professional purposes. Even if the interest in social media isstrong in the private domain, the use is far less widespread in organizations. The trajectory of traditional information spread through web platforms into use of new and open social media platforms stresses organization's and professionals to enrich user-generated content and take part in and enhance social networking. This study explore how social media is used in organizations and how professionals´ practice is challenged by use of social media of reaching out, sharing knowledge and interaction with target groups. Through illustration of two research cases; municipality-citizens' interactions and university-industry collaborations, three affordances of social media practice are emerging; incentives, perceptions and openness, where social media is constituted as the boundary object

  • 21.
    Heras Aguilar, Sergio
    University West, Department of Engineering Science, Division of Production System.
    Comparison and visualization of robot program modifications: Applied on ABB industrial robots at Volvo Cars Corporation2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Volvo Cars Corporation creates robot programs off-line for all new robot implementations for virtual commissioning. These virtually created robot programs are then downloaded to the real robot, after the installation has been carried out, to be tested before they are fully operational. These tests are spanned from robot installation until full production, adjusting the robot programme according to Volvo Cars specification and correcting errors that the robot program may have. Changes of the robot programs will be saved each time it is modified, generating a series of backups for each robot until the robot is correctly adjusted along all the steps of the process. To improve the offline programming there is a necessity for visualize the modifications made during the physical robot commissioning. The objective of this thesis is to identify, categorise, quantify and visualize modifications between each different backup of a robot. A software application has been developed using Microsoft Visual Studio using C#. The application is designed in windows for different types of data. It enables the user to compare two robot programs (two different backup programs from the tests) from one robot and see the result between them graphically. The graphs are designed interactively so that the user can filter the information to see the desired data from the robot programs comparison. Key performance indicators (KPIs) has been specified for RobTargets and Procedures according to Volvo Cars Corporation requests. These KPIs are implemented and visualised in a graphical representation.

  • 22.
    Hussain, Dena
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Production System.
    Utilizing ICT Tools when Developing Healthcare Processes and Action Plans for Special Needs Children2016In: Proceedings 2016 IEEE First International Conference on Connected Health: Applications, Systems and Engineering Technologies (CHASE), IEEE Computer Society, 2016, 334-335 p., 7545853Conference paper (Refereed)
    Abstract [en]

    Technological advances lead to the development of an increasing number of computer-based devices and software applications, used in the healthcare sector. Recently, rehabilitation programs involving special need children in Sweden have been the focused for these applications. The aim of this project is to create an evidence-based online platform that can be used on a computer or media pads directly together with the child. The platform should help different caretakers to structure their work, hence forward and enhance action plans for individuals with special needs. A secondary aim is to identify gaps in the existing approach to stimulate future research efforts to develop new Information and Communication Technologies (ICT) in this context. By utilizing ICT tools to create a more integrated communication platform between different regions in the healthcare sector and rehabilitation programs, we hope to verify, via this study, the growths and understanding of how improved communication affects can change the process in regards to creating action plans and support organizations in creating efficient connections.

  • 23.
    Johansson, Anders
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West. Global Industrial Development, Scania CV AB, Södertälje.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Production System.
    Pejryd, Lars
    School of Science and Technology, Örebro University.
    Manufacturing System Design for Business Value, a Holistic Design Approach2016In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 50, 659-664 p.Article in journal (Refereed)
    Abstract [en]

    When designing and developing manufacturing systems, many aspects need to be considered. Typically, the manufacturing design objectives are specified to achieve certain operational requirements around quality, capacity, cost etc. They are also specified withthe intention to ensure efficient processes related to manufacturing, such as maintenance, logistics, not to mention the main process of manufacturing the actual part. This study proposes that a wider company perspective should be considered during manufacturing system design, to achieve a greater business value. The manufacturing system should be designed to create value to other core business processes, such as product development, marketing, sales and services. This paper also presents examples on value perspectives to consider and how this approach can be implemented.

  • 24.
    Johansson, Anders
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West. Global Industrial Development, Scania CV AB, Södertälje.
    Pejryd, Lars
    School of Science and Technology, Örebro University.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Production System.
    Production support model to manage market demand volatility risks2016In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 57C, 664-668 p.Article in journal (Refereed)
    Abstract [en]

    In the investment selection process during the design of new manufacturing systems, both the technical attributes and the expected financial performance need to be evaluated. To manage the financial risks with market volatility, it is important to understand the composition of fixed and variable cost factors in relation to the expected volume interval. The support model developed in this paper will in a simple and intuitive way visualise the effect on production cost due to changes in market demands. It can also be used to evaluate the volume sensitivity of existing manufacturing systems, even compare systems making different products.

  • 25.
    Lindqvist, Björn
    University West, Department of Engineering Science, Division of Production System.
    Multi-axis industrial robot braking distance measurements: For risk assessments with virtual safety zones on industrial robots2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Industrial robots are increasingly used within the manufacturing industry, especially in collaborative applications, where robots and operators are intended to work together in certain tasks. This collaboration needs to be safe, to ensure that an operator does not get injured in any way. One of several solutions to this is to use virtual safety zones, which limits the robots working range and area to operate within, and may be more flexible than physical fences. When the robot exceeds the allowed limit of the virtual safety zone, a control system that monitors the robot position, forces to robot to stop. Depending on the current speed and payload of the robot, the initialized stop has a braking distance until the robot has completely stopped. How far the separation distance between human and robot must be, is calculated using ISO-standard guidelines when doing risk assessments. To support affected personnel in their work, an investigation and experimentation of braking distances among several robots has been conducted. These testing experiments have been designed to simulate a collaborative operation which is an excessive risk in a robot cell. The tests have been performed with various speeds and payloads, for comparison between the robot models and for validation against already existing data. The difference with this study compared to existing ones is that several robot axis’ are used simultaneously in the testing movements, which is a benefit since a robot rarely operates with only one axis at a time.  Main results of the performed tests are that the robot doesn’t obtain speeds over 2000 mm/s when axis 1 is not involved, before the virtual safety zone is reached. Axis 1 can generate the highest speeds overall, and is therefore a significant factor of the braking distance. The results and conclusions from this thesis states that these kinds of tests give useful information to the industry when it comes to safety separation distance and risk assessments. When applying the information in a correct way, the benefits are that a shorter safety separation distance can be used without compromising on safety. This leads to great advantages in robot cell design, because space is limited on the factory floor.

  • 26. MacKinnon, S.N.
    et al.
    Hartler, J.
    Olindersson, F.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Production System.
    How do experienced mariners perceive vessel risk in constricted navigation settings?2016In: Proc. of 19th International Navigation Simulator Lecturers' Conference (INSLC'16), 2016Conference paper (Other academic)
  • 27.
    Magalhães, Ana
    University West, Department of Engineering Science, Division of Production System.
    Thermo-electric temperature measurements in friction stir welding: Towards feedback control of temperature2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Friction Stir Welding has seen a fast uptake in many industry segments. Mechanical properties superior to fusion welding, the ability to weld "unweldable" aluminium alloys and low distortion are often described as the main reasons for the fast industrial implementation of FSW. Most existing applications consist of long straight welding joints. Applications with complex weld geometries, however, are rarely produced by FSW. These geometries can induce thermal variations during the welding process, thus making it challenging to maintain a consistent weld quality. In-process adaptation of weld parameters to respond to geometrical variations and other environmental variants allow new design opportunities for FSW. Weld quality has been shown to be reliant on the welding temperature. However, the optimal methodology to control the temperature is still under development.The research work presented in this thesis focuses on some steps to take in order to reach the improvement of the FSW temperature controller, thus reach a better and consistent weld quality. In the present work different temperature methods were evaluated. Temperature measurements acquired by the tool-workpiece thermocouple (TWT) method were accurate and fast, and thereby enhanced suitable for the controller. Different environmental conditions influencing the material heat dissipation were imposed in order to verify the controller effect on the joint quality. In comparison with no controlled weld, the use of the controller enabled a fast optimization of welding parameters for the different conditions, leading to an improvement of the mechanical properties of the joint.For short weld lengths, such as stitch welds, the initial plunge and dwell stages occupy a large part of the total process time. In this work temperature control was applied during these stages. This approach makes the plunge and dwell stages more robust by preventing local material overheating, which could lead to a tool meltdown. The TWT method was demonstrated to allow a good process control during plunging and continuous welding. The approach proposed for control offers weld quality consistency and improvement. Also, it allows a reduction of the time required for the development of optimal parameters, providing a fast adaptation to disturbances during welding and, by decreasing the plunge time, provides a significant decrease on the process time for short welds.

  • 28.
    Nilsen, Morgan
    University West, Department of Engineering Science, Division of Production System.
    Optical detection of joint position in zero gap laser beam welding2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents an experimental study on how to track zero gaps between metal sheets to be joined by laser beam butt welding. Automated laser beam welding is gaining interest due to its ability to produce narrow and deep welds giving limited heat input and therefore less distortions compared to other processes, such as arc-welding. The automated laser beam welding process is however sensitive to how the high power laser is positioned with regards to the joint position. Deviations from the joint position may occur due to inaccuracies of the welding robot and fixturing, changes in joint geometry, process induced distortions, etc. Welding with an offset from the joint position can result inlack of sidewall fusion, a serious defect that is hard to detect. This work develops and evaluates three monitoring systems to be used during welding in order to be able to later control the laser beam spot position. (i) A monitoring systemis developed for three different photo diodes, one for the visual spectrum of the process emissions, one for the infrared spectrum, and one for the reflected highpower laser light. The correlation between the signals from the photodiodes and the welding position relative to the joint is analysed using a change detection algorithm. In this way an indication of a path deviation is given. (ii) A visual camera with matching illumination and optical filters is integrated into the laser beam welding tool in order to obtain images of the area in front of the melt pool. This gives a relatively clear view of the joint position even during intense spectral disturbances emitted from the process, and by applying animage processing algorithm and a model based filtering method the joint positionis estimated with an accuracy of 0.1 mm. (iii) By monitoring the spectral emissions from the laser induced plasma plume using a high speed and high resolution spectrometer, the plasma electron temperature can be estimated from the intensities of two selected spectral lines and this is correlated to the welding position and can be used for finding the joint position.

  • 29.
    Nilsen, Morgan
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Production System.
    Christiansson, Anna Karin
    University West, Department of Engineering Science, Division of Production System.
    Joint tracking in zero gap laser beam welding using a vision sensor2016In: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings: 25th – 27th of October 2016, Lund: Swedish Production Academy , 2016, 1-7 p.Conference paper (Refereed)
    Abstract [en]

    The paper describes a robust vision sensor system that can find very narrow gaps between metal sheets to be butt welded together. The use of automated laser beam welding is seen as a key enabler for efficient manufacturing by enabling narrow and deep welds with a limited heat affected zone and low thermal distortion of the welded components. It is sensitive to positioning the laser beam with respect to the joint position. Even a small off-set from the actual joint could result in detrimental lack of fusion. The system comprises a CMOS camera with optic filters integrated in the welding optics and appropriate LED illumination of the work piece. By analysing the spectral emissions during welding, illumination and matching optic filters have been chosen in a spectral range where the process disturbances are relatively low. In this way it has been shown possible to detect the joint position even during harsh welding conditions. Preliminary results from the first experiments show promising results, however more tests will be performed using different weld geometries etc. to verify the robustness of the algorithm.

  • 30.
    Nilsen, Morgan
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Production System.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science, Division of Production System.
    Ancona, Antonio
    University West, Department of Engineering Science, Division of Production System. IFN-CNR Institute for Photonics and Nanotechnologies, Physics Department, via Amendola 173, 70126 BARI, Italy.
    Vision and spectroscopic sensing for joint tracing in narrow gap laser butt welding2017In: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 96, 107-116 p.Article in journal (Refereed)
    Abstract [en]

    The automated laser beam butt welding process is sensitive to positioning the laser beam with respect to the joint because a small offset may result in detrimental lack of sidewall fusion. This problem is even more pronounced incase of narrow gap butt welding, where most of the commercial automatic joint tracing system fail to detect the exact position and size of the gap. In this work, adual vision and spectroscopic sensing approach is proposed to trace narrow gap butt joints during laser welding. The system consists of a camera with suitable illumination and matched optical filters and a fast miniature spectrometer. An image processing algorithm of the camera recordings has been developed in order to estimate the laser spot position relative the joint position. The spectral emissions from the laser induced plasma plume has been acquired by the spectrometer, and based on the measurements of the intensities of selected lines of the spectrum, the electron temperature signal has been calculated and correlated to variations of process conditions. The individual performances of these two systems have been experimentally investigated and evaluated offline by data from several welding experiments where artificial abrupt as well as gradual excursions of the laser beam out of the joint were produced. Results indicate thata combination of the information provided by the vision and spectroscopic systems is beneficial for development of a hybrid sensing system for joint tracing.

  • 31.
    Norström, Livia
    et al.
    University West, Department of Economics and IT, Division of Media and Design.
    Hattinger, Monika
    University West, Department of Engineering Science, Division of Production System.
    Efforts at the boundaries: Social media use in Swedish municipalities2016In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 9821, 123-137 p.Article in journal (Refereed)
    Abstract [en]

    Social media is used by the majority of Swedish municipalities. However, the highly interactive features of social media are often not taken advantage of. The study aims to get a better understanding of why social media is not used to its full potential in the municipality. Findings from an interview study with communicators in three Swedish municipalities reveal that the motivation for using social media is often difficult to turn into action. Tensions emerging in the use of social media result in hesitation, uncertainty and a slowing down of work practice. The processes of managing the tensions are characterized by boundary crossing between different communities, such as municipal communicators, elected officials and citizens, with social media itself as an equally important actor. The processes of boundary crossing by the municipal communicators are discussed in terms of learning processes and new emerging competences that might redefine the role of the municipal communicator and hence perhaps the public servant in general. © IFIP International Federation for Information Processing 2016.

  • 32.
    Parthasarathy, Prithwick
    University West, Department of Engineering Science, Division of Production System.
    Model for energy consumption of 2D Belt Robot: Master’s thesis work2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A production industry with many robots working 24 hours a day, 7 days a week consumes a lot of energy. Industries aim to reduce the energy consumed per machine so as to support their financial budgets and also to be a more sustainable, energy efficient entity. Energy models can be used to predict the energy consumed by robot(s) for optimising the input parameters which determine robot motion and task execution. This work presents an ener-gy model to predict the energy consumption of 2D belt robots used for press line tending. Based on the components' specifications and the trajectory, an estimation of the energy consumption is computed. As part of this work, the proposed energy model is formulated, implemented in MATLAB and experimentally validated. The energy model is further used to investigate the effect of tool weight on energy consumption which includes predicting potential energy reductions achieved by reducing the weight of the gripper tools. Further, investigation of potential energy savings which can be achieved when mechanical brakes are used when the robot is idle is also presented. This illustrates the purpose and usefulness of the proposed energy model.

  • 33.
    Rajagopalan, Prashanth
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Robot cell for Akerstedts2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Akerstedts is an industrial fan company which manufactures different kinds of fans like axial fans, radial fans and chimney fans. Since the company's mode of welding fans is manual and its disadvantages pose major threats to the safety of the humans working with it, the welding process needs to be automated to eliminate the disadvantages and ensure safety and quality. In this thesis, a number of solutions have been proposed to design cell layouts. These designs of cell layouts have been created using off line programming with the help of a software called Robot Studio. To design each cell layout every component of it like the robot, fixture, welding gun, peripherals, safety systems etc. have been carefully analysed and selected depending on what is exactly required. Also each cell was optimized to give the best possible output in terms of total cost, pro-duction rate and time, total surface area occupied by the cell and safety. Later these as-pects for each solution were analysed to pick out the best solution suitable for the com-pany. The various solutions have been visually shown through pictures and simulations and the analysis have been shown graphically.

  • 34.
    Riisggard, Anton
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Eliasson, Per-Albin
    University West, Department of Engineering Science, Division of Production System.
    Mapping of camera-controlled front lighting systems for passenger cars2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    More and more carmakers equip their cars with lighting systems that adapt to different driving conditions. Recently, new systems have arrived on the market and it is important for ÅF Automotive & Vehicle in Trollhättan to acquire knowledge regarding several aspects of the European market. The main objective of the thesis is therefore to provide a general idea of various LED-array/matrix concepts available on this market. Other objectives comprise price-setting strategies, purchasing costs, brand awareness using signature headlights, legal requirements and customer experience. Several research questions have been defined in order to fulfil the thesis aims.

    The methodology leading up to the results is mostly based on literature studies but also comprises interviews, car dealer visits and test driving cars. LED-array/matrix systems are available on:

    •  Audi – Audi Matrix LED
    •  Mercedes-Benz: Multibeam
    •  Mazda – Adaptive LED Headlights
    •  BMW – BMW Adaptive LED
    •  Opel – Opel IntelliLux

    The systems are available on models in the C-, D-, E-, F-, S- and J-segments and are available as either standalone features, part of packages or included in the baseline equipment. Comparisons are made regarding the purchasing costs of identified systems. Signature headlights and design philosophy's, which different car makers use in order to create brand awareness have also been outlined. Furthermore, systems have been identified which yet are not fitted in specific cars. These systems are also described and in addition, the suppliers of these have been mapped. Valeo, Automotive Lighting, Koito, Varroc and ZKW have been identified. The legal requirements that need to be considered as limiting factors, as stated in ECE Vehicle Regulations No. 48 and 123, have also been identified and summarised. Finally, test driving results from two occasions are presented and analysed, featuring Mercedes-Benz A-class in the first and Mazda CX-5 in the second.

    The delivered results are discussed and several conclusions are drawn in this thesis, which hopefully sets a platform for this field of engineering and future work at ÅF.

  • 35.
    Runnemalm, Anna
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Production System.
    Garcia de la Yedra, Aitor
    IK4-LORTEK, Ordizia, Spain.
    Fuente, Raquel
    IK4-LORTEK, Ordizia, Spain.
    Beizama, Ane Miren
    IK4-LORTEK, Ordizia, Spain.
    Fernandez, Erik
    IK4-LORTEK, Ordizia, Spain.
    Thorpe, Nigel
    Tecnitest ingenieros, Madrid, Spain.
    Henriksson, Per
    GKN Aerospace Engine Systems Sweden, Trollhättan, Sweden.
    Automated inspection of welds with limited access by use of active thermography with laser line excitation2016Conference paper (Other academic)
    Abstract [en]

    Inspection of welds for detecting surface breaking defects is traditionally performed by using NDT methods such as Fluorescent Penetrant Inspection, Visual Inspection or Eddy Current. All those well-known techniques have drawbacks, as they need access to the surface, either for preparation with e.g. liquids or for using contact probes. Traditional methods also require a skilled operator to carry out the inspection, and moreover to analyse the obtained results. Furthermore, for the inspection of welds with limited access, the use of those traditional methods is even more complex, resulting in increased inspection time and reduced detection capability or in worst case, areas impossible to inspect. Therefore, the development of a fully automated non-contact method overcoming these limitations is desired. ;Active thermography is a novel NDT technique for weld inspection. The method has shown promising results for replacing traditional techniques when it comes to detection of surface breaking defects in metals. The method make use of an excitation source in order to heat the sample in a controlled manner during the test, and an infrared thermal camera for recordings of the thermal evolution. ;In this work, an automated solution developed and demonstrated for inspection of welds in a jet-engine component with limited access is presented. The NDT system is mounted on an industrial robot, making it possible to automatic scan the inspected area. The system consists of a, continuous laser-line excitation source together with a FLIR SC 655 microbolometer thermographic camera. In order to access limited areas, two polished aluminium mirrors have been used for both infrared radiation monitoring and laser excitation respectively. A solution for automatic analysing, defect detection and sizing is also included and presented.

  • 36.
    Sikström, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Ericson Öberg, Anna
    Volvo Construction Equipment, Arvika, Sweden.
    Prediction of penetration in one-sided fillet welds by in-process joint gap monitoring: an experimental study2017In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 61, no 3, 529-537 p.Article in journal (Refereed)
    Abstract [en]

    The challenge to predict variations in penetration depth in one-sided fillet welds during robotized gas metal arc welding has been addressed by a pilot investigation of technical possibilities and limitations. The main cause for the variation in penetration depth is considered to be variation in joint gap size. Special attention has been paid in order to adopt the experimental conditions to conform to industrial welding conditions. The employed method uses in-process monitoring of joint gap size together with an empirical model relating penetration depth to gap size in order to predict this depth. The gap size estimates are based on image information from two cameras, one visual and one infrared. The results, that are evaluated off-line, confirm the development of a real-time method providing technical solutions that are industrially tractable. The results also pinpoint areas of further improvements towards increased robustness and reduced estimation uncertainties.

  • 37.
    Sikström, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Production System.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Production System.
    Nilsen, Morgan
    University West, Department of Engineering Science, Division of Production System.
    Svenman, Edvard
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Evaluation of non-contact methods for joint tracking in a laser beam welding application2016In: The 7th International Swedish Production Symposium, Conference Proceedings: 25th – 27th of October 2016, Lund: Swedish Production Symposium , 2016, 1-6 p.Conference paper (Other academic)
    Abstract [en]

    The use of automated laser welding is a key enabler for resource efficient manufacturing in several industrial sectors. One disadvantage with laser welding is the narrow tolerance requirements in the joint fit-up. This is the main reason for the importance of joint tracking systems. This paper describes anevaluation of four non-contact measurement methods to measure the position, gap width and misalignment between superalloy plates. The evaluation was carried out for increased knowledge about the possibilities and limitations with the different methods. The methods are vision-, laser-line-,thermography- and inductive probe systems which are compared in an experimental setup representing a relevant industrial application. Vision is based on a CMOS camera, where the image information is used directly for the measurements. Laser-line is based on triangulation between a camera and a projected laserline. Thermography detects the heat increase in the gap width due to external heat excitation. Inductive probe uses two eddy current coils, and by a complex response method possibilities to narrow gap measurement is achieved. The results, evaluated by comparing the data from the different systems, clearly highlights possibilities and limitations with respective method and serves as a guide in the development of laser beam welding.

  • 38.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Production System.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Production System.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Production System.
    Analysis of Plunge and Dwell Parameters of Robotic FSW Using TWT Temperature Feedback Control2016In: Proceedings of 11th International Symposium on Friction Stir Welding, Cambridge, UK, 2016, 1-11 p.Conference paper (Other academic)
    Abstract [en]

    Friction stir welding (FSW) and variants of the process have generated high interest in many industries due to its several advantages such as low distortion, superior mechanical properties over arc welding and the possibility of joining dissimilar materials. Increased complexity of industrial applications require a better control of the welding process in order to guarantee a consistent weld quality. This can be achieved by implementing feedback control based on sensor measurements. Previous studies have demonstrated a direct effect of weld temperature on the mechanical properties of FSW joints, [1], and therefore, temperature is chosen as primary process variable in this study.A new method for temperature measurement in FSW referred to as the Tool-WorkpieceThermocouple (TWT) method has recently been developed by De Backer. The TWT method is based on thermoelectric effect and allows accurate, fast and industrially suitable temperature monitoring during welding, without the need for thermocouples inside the tool [2].This paper presents an application of the TWT method for optimisation of the initial weld phases, plunge and dwell, operation in conventional FSW, which can also be applied to friction stir spot welding (FSSW). An analysis of the operation parameters by using feedback temperature control is presented aiming to better control of the initial weld phases through temperature feedback.

    The introduction of the TWT temperature sensor provides additional process information during welding. Fast data acquisition gives opportunity to differentiate different process phases: contact of probe tip with workpiece surface; plunge phase; dwell phase. This would be followed by tool retraction for FSSW or tool traverse phase for FSW.The effect of the plunge parameters on weld temperature and duration of each phase were studied for the purpose of optimising the process with respect to process (i) robustness, (ii)time, (iii) robot deflection and (iv) quality. By using temperature feedback, it is possible to control the plunge phase to reach a predefined weld temperature, avoiding overheating of the material, which is known to have a detrimental influence on mechanical properties. The work presented in this paper is an important step in the optimization of robotic FSSW and FSW.

  • 39.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Production System.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Production System.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Production System.
    Temperature measurements during friction stir welding2017In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 88, no 9-12, 2899-2908 p.Article in journal (Refereed)
    Abstract [en]

    The increasing industrial demand for lighter, more complex and multi-material components supports the development of novel joining processes with increased automation and process control. Friction stir welding (FSW) is such a process and has seen a fast development in several industries.This welding technique gives the opportunity of automation and online feedback control, allowing automatic adaptation to environmental and geometrical variations of the component.Weld temperature is related to the weld quality and therefore proposed to be used for feedback control. For this purpose, accurate temperature measurements are required. This paper presents an overview of temperature measurement methods applied to the FSW process. Three methods were evaluated in this work: thermocouples embedded in the tool, thermocouples embedded in the workpiece and the tool-workpiece thermocouple(TWT) method. The results show that TWT is an accurate and fast method suitable for feedback control of FSW.

  • 40.
    Svenman, Edvard
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West. GKN Aerospace.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Production System.
    A complex response inductive method for improved gap measurement in laser welding2017In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 88, no 1-4, 175-184 p.Article in journal (Refereed)
    Abstract [en]

    Laser welding needs precise measurement of weldgap position to avoid weld defects. Most often, optical measurement methods are used, but well-aligned narrow gaps canbe difficult to detect. An improved inductive method capable of detecting zero gaps in square butt joints is proposed. The new method uses two eddy current coils, one on each side of the gap, and measures the complex response of the individual coils, i.e. both the inductive and resistive response. By combining the coil responses, both the position and the geometry of the weld gap can be estimated. The method was experimentally investigated by traversing a single coil over an adjustable gap between two plates and combining the measured coil responses into a simulated two-coil probe. The gap was adjusted in both misalignment and gap width up to 0.4 mm. Comparing the results to known settings and positions shows that gap position is measured to within 0.1 mm, if the probe is within a working area of 1 mm from the gap in both position and height. Results from the new method were compared to simulations, from the same experimental data, of a previously reported method where the coils were electrically combined by wiring them together. The previous method can give accurate results but has a much smaller working area and depends on servo actuation to position the probe above the gap. The improved method gives better tolerance to varying misalignment and gap width, which is an advantage over previous inductive methods.

  • 41.
    Svenman, Edvard
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West. GKN Aerospace Engine Systems.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Production System.
    Model based compensation of systematic errors in an inductive gap measurement method2017In: Measurement, ISSN 0263-2241, Vol. 105, 17-24 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents an improvement to a recently presented inductive gap measurement method, using a model to reduce systematic errors. Gap measurement is important in laser keyhole welding, where the laser beam and the resulting weld seam are very narrow, requiring high precision in alignment and gap preparation. The previously reported method for gap measurement uses one inductive coil on each side of the gap, each measuring distance to the gap and lift off above a plate, to estimate the position, width and alignment of the gap in a square butt joint. The method can detect zero width gap and shows position error less than 0.1 mm, but gap width and alignment measurement suffer from systematic errors. The improvement is based on a model that is designed to describe these systematic errors as functions of the gap dimensions. The model relies on observations of experimental data, and is calibrated to a small set of measurements. Using the model with the initial estimate of the gap dimensions to compensate the coil measurements, an improved estimate of the gap dimensions can be calculated. The errors in the compensated results are within 0.1 mm except for gap width, which still suffers from the effect of combined gap width and misalignment.

  • 42.
    Tricarico, L.
    et al.
    DMMM – Politecnico di Bari, viale Japigia 182, Bari, Italy.
    Ancona, Antonio
    University West, Department of Engineering Science, Division of Production System. CNR-IFN UOS Bari, via Amendola 173, 70126 Bari, Italy.
    Palumbo, G.
    DMMM – Politecnico di Bari, viale Japigia 182, Bari, Italy.
    Sorgente, D.
    CNR-IFN UOS Bari, via Amendola 173, Bari, Italy.
    Spina, R.
    DMMM – Politecnico di Bari, viale Japigia 182, Bari, Italy.
    Lugarà, P.M.
    CNR-IFN UOS Bari, via Amendola 173, Bari, Italy.
    Discrete spot laser hardening and remelting with a high-brilliance source for surface structuring of a hypereutectoid steel2017In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 115, 194-202 p.Article in journal (Refereed)
    Abstract [en]

    In this work the single-pulse laser irradiation of a hypereutectoid steel was investigated using a fiber laser source, in a range of process parameters enabling surface hardening and remelting. Effects of laser power, pulse energy and defocusing distance were investigated using a numerical/experimental approach. Laser surface treatments were conducted on uncoated samples without any gas shielding, changing both the laser power and the pulse energy, and exploring a wide range of defocusing distances. Numerical simulations were conducted using a finite element model calibrated by means of an optimization procedure based on a specific calculation algorithm and using a subset of experimental data producing surface melting. Using both simulations and experiments, the process operating windows of the discrete spot laser treatment were determined: it was found that, when varying the laser power between 250 W and 750 W, melt-free hardened zones are produced with a maximum extension between 0.7 mm and 1.0 mm; on the contrary, in case of more tightly beam focusing conditions, surface melting occurred with a size of the re-melted areas ranging between 1.0 mm and 1.4 mm. Results further showed that a small change (generally 2–3 mm) of the defocusing distance suddenly brings the material from melting to a non-hardening condition. © 2016 Elsevier Ltd

  • 43.
    Tumkur Sampathu, Shashishekar
    University West, Department of Engineering Science, Division of Production System.
    Offline programming for 3D printing using ABB robot: Automatic path generation2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    3D printing is one of the additive manufacturing process in which product is created layer by layer. In almost all 3D printing first computer aided drawing (CAD) model is generated then it is coveted into Standard Tessellation language (STL) file format after that it is sliced to generate the toolpath for printer. In the thesis process planning for 3D printing using industrial robot is identified and verified. 3D printing is performed by industrial robot using feeder tool which feeds the plastic through the nozzle. The wire which is fed for 3D printing is controlled by Arduino Uno. For generating the path for 3D printing an add-in called RMD is used in process simulate. Add-in RMD is developed by University west.

    First goal of thesis is to find process planning steps for the robotics 3D printing which involves all the process starting from CAD to final product and verify all the steps. The other goal is to find the process parameter which affects final products. Process planning steps from CAD to final product is identified and verified. The process planning step involves modelling, layer and manufacturing all these steps are verified and final product is produced. In modelling step the part that is to be manufactured is modelled. In layer step the pre-processing like converting 3D solid CAD model into layers that in turn is converted to robot code is done. In manufacturing step the downloaded robot code is loaded to real robot and the part is manufactured. Next is to find the process parameters which affects the final product. The process parameter which affects the final products are found. Since there are many parameters which affects the final product so only three process parameter like layer thickness, speed of robot and path to path width is selected based on literature. In order to verify this parameter experiment was designed according to Taguchi method at three levels then the surface roughness of 3D printed sample are measured using surface measuring instrument. According to analysis of S/N ratio and analysis of variance layer thickness was found to affect the final product more than the other two parameter. After layer thickness speed deposition has more effect on final product.

  • 44.
    Ulucan Dayan, Civan
    University West, Department of Engineering Science, Division of Production System.
    Evaluation of an External Axis for Tool Manipulation in Robotized Laser Beam Welding2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Laser beam welding applications are widely used in the industry. However, laser beam welding applications have a very small position tolerance to an offset. In this project, the offset is defined as the distance between the point, which the laser tool welds, and the point which laser tool should weld the weld joint. In other words, the offset is the position error in a welding application. To perform successful welding, the laser beam must hit the exact coordinate of the weld joints to weld the parts together. For dealing with these inaccuracy issues, tool manipulation systems can be used. In this project, an external axis is used for the precise manipulation of the laser beam welding tool as a complement to robotic nominal movement. Input data to the external axis system is obtained from an image from a vision system of the work pieces which need to be welded.

    Tool manipulation systems are used to manipulate tools to ensure certain position accuracy during any application. The tool manipulation system in this project has two main parts; a seam tracking system (outside this project) and an external axis system. The seam tracking system gives an on-line measurement of the offset, and that there is a feedback loop with a controller, which gives the system information about how much to manipulate the external axis module to the external axis system. The seam tracking system consists of two main parts; a camera and the seam tracking image processing program. In the seam tracking system, a camera takes images of the work pieces which shall be welded. Then the seam tracking program calculates the offset by image processing. This estimated offset is the input for the external axis system. The external axis system has three main parts; the external axis program, input-output module and the external axis module. The external axis program is the system which controls the input-output module for manipulating the external axis module in this project. The external axis module manipulates the laser beam welding tool by changing the orientation of the tool in order to reduce the offset. This project is about the external axis system.

    There is a relationship between the offset input and the required manipulation angle of the external axis. In this project, the required manipulation angle is the external axis angle. By using this relationship, the laser beam welding tool can be manipulated to weld in the desired position. The same system can be used in applications which require high position accuracy.

    The evaluation of the external axis system emphasizes that the accuracy demand of the laser beam welding applications can be satisfied by an external axis system. However, the investigated external axis system behaves in a way that when the offset is larger than it supposed to be, the speed of the TCP movement slows down.

  • 45.
    Volpe, A.
    et al.
    CNR-IFN, Institute for Photonics and Nanotechnologies, S.S. Bari, via Amendola 173, Bari, Italy.
    Ancona, Antonio
    University West, Department of Engineering Science, Division of Production System. CNR-IFN, Institute for Photonics and Nanotechnologies, S.S. Bari, via Amendola 173, Bari, Italy.
    Trotta, G.
    CNR-ITIA, Institute of Industrial Technology and Automation, Bari, Italy.
    Vázquez, R. M.
    CNR-IFN, Institute for Photonics and Nanotechnologies, Milan, Italy.
    Fassi, I.
    CNR-ITIA, Institute of Industrial Technology and Automation, Milan, Italy.
    Osellame, R.
    CNR-IFN, Institute for Photonics and Nanotechnologies, Milan, Italy.
    Fabrication and assembling of a microfluidic optical stretcher polymeric chip combining femtosecond laser and micro injection molding technologies2017In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, 100920FArticle in journal (Refereed)
    Abstract [en]

    Microfluidic optical stretchers are valuable optofluidic devices for studying single cell mechanical properties. These usually consist of a single microfluidic channel where cells, with dimensions ranging from 5 to 20 Όm are trapped and manipulated through optical forces induced by two counter-propagating laser beams. Recently, monolithic optical stretchers have been directly fabricated in fused silica by femtosecond laser micromachining (FLM). Such a technology allows writing in a single step in the substrate volume both the microfluidic channel and the optical waveguides with a high degree of precision and flexibility. However, this method is very slow and cannot be applied to cheaper materials like polymers. Therefore, novel technological platforms are needed to boost the production of such devices on a mass scale. In this work, we propose integration of FLM with micro-injection moulding (ΌIM) as a novel route towards the cost-effective and flexible manufacturing of polymeric Lab-on-a-Chip (LOC) devices. In particular, we have fabricated and assembled a polymethylmethacrylate (PMMA) microfluidic optical stretcher by exploiting firstly FLM to manufacture a metallic mould prototype with reconfigurable inserts. Afterwards, such mould was employed for the production, through ΌIM, of the two PMMA thin plates composing the device. The microchannel with reservoirs and lodgings for the optical fibers delivering the laser radiation for cell trapping were reproduced on one plate, while the other included access holes to the channel. The device was assembled by direct fs-laser welding, ensuring sealing of the channel and avoiding thermal deformation and/or contamination. © 2017 SPIE.

  • 46.
    Wang, Yueyue
    University West, Department of Engineering Science, Division of Production System.
    Theoretical experiment of GISSMO failure model for Advanced High Strength Steel2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    When developing an electric vehicle, it is essential to evaluate the deformation in and around the battery box for different crash scenarios, and it is necessary to develop a more advanced model that would take into account all the stress modes. Thanks to the excellent properties of Advanced High Strength Steel (AHSS) combine with high strength for more safety and weight reduction for less exhaust emission, AHSS is more and more commonly used in automobile industry. The material employed in this project is DOCOL 900M and it is a martensitic steel with yield strength higher than 700MPa.  The focus of the current work is to describe the experimental setup for the GISSMO model used in LS-DYNA. A number of experimental methods and theories have been reviewed. Different geometries of the test specimens under different stress triaxialities have been discussed. The study also compares the accuracy and robustness of each of the testing methods and setups. The effect of anisotropy of materials on the mechanical properties was studied. Some summaries about how to reduce errors in the experiment under the conditions of low costing and high efficiency have been discussed. According to the stress-strain response of ductile materials, the parameters of plasticity model can be calibrated. The material can be implemented in finite element software to calibrate the parameters of damage and the prediction of material failure can be achieved. The experiment and simulation are always good to be used together in the research.

  • 47.
    Wärmefjord, Kristina
    et al.
    a Chalmers University of Technology, Dept. of Product and Production Development, SE-412 96 Gothenburg, Sweden.
    Söderberg, Rikard
    a Chalmers University of Technology, Dept. of Product and Production Development, SE-412 96 Gothenburg, Sweden.
    Ericsson, Mikael
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Appelgren, Anders
    University West, Department of Engineering Science, Division of Production System.
    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
    a 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 tests2016In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 43, 136-141 p.Article in journal (Refereed)
    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.

  • 48.
    Yan, Nannan
    University West, Department of Engineering Science, Division of Production System.
    Safe Human Robot Collaboration: By using laser scanners, robot safety monitoring system and trap routine speed control2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays, robot is commonly used to perform automation tasks. With the trend of low volume and customised products, flexible manufacturing is introduced to increase working efficiency and flexibility. Therefore, human robot collaboration plays an important role in automation production and safety should be considered in the design of this kind of robot cell. This work presents the design of safe human robot collaboration by equipping an industrial robot cell with SICK laser scanners, safety monitoring system and trap routine speed control. It also investigates the reliability of RGB-D camera for robot safety. This work aims to find a safety robot system using standard industrial robot for human robot collaboration. The challenge is to ensure the operator's safety at all times. It investigates safety standards and directives, safety requirements of collaboration, and related works for the design of collaborative robot cell, and makes risk assessment before carrying out the valuation. Based on literature review, it gives the concept of layout design and logic for slow down and resume of robot motion. The speed will be first reduced to manual speed and then zero speed depending on the distance between the human and the robot. Valuation and verification are made in the proposed safe solution for human robot collaboration to test the reliability and feasibility. This project realizes the automatic resume that the robot can con-tinue working without manually pressing reset button after the operator leaves the robot cell if there is no access to the prohibited area. In addition, it also adopts the manual reset at the same time to ensure the safety when people access the prohibited area. Several special cases that may happen in the human robot collaboration are described and analysed. Furthermore, the future work is presented to make improvements for the proposed safety robot cell design.

  • 49.
    Öberg, Anna Ericson
    et al.
    Volvo Construction EquipmentArvikaSweden.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Production System.
    Barriers for industrial implementation of in-process monitoring of weld penetration for quality control2017In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 91, no 5-8, 2427-2434 p.Article in journal (Refereed)
    Abstract [en]

    The research conducted sheds a light on the question why robust in-process monitoring and adaptive control are not fully implemented in the welding industry. In the research project FaRoMonitA, the possibilities to monitor the weld quality during welding have been investigated. Research conducted in this area has merely focused on technical issues investigated in a laboratory environment. To advance the research front and release some barriers related to industrial acceptance, the studies conducted in this paper have been both quantitative and qualitative in form of experiments combined with an interview study. The quality property weld penetration depth was chosen for in-process monitoring to evaluate the industrial relevance and applicability. A guaranteed weld penetration depth is critical for companies producing parts influenced by fatigue. The parts studied were fillet welds produced by gas metal arc welding. The experiments show that there is a relationship between final penetration depth and monitored arc voltage signals and images captured by CMOS vision and infrared cameras during welding. There are still technical issues to be solved to reach a robust solution. The interview study indicates that soft issues, like competence and financial aspects, are just as critical.

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