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  • 1.
    Arora, Siddhant
    et al.
    School of Computer Science and Engineering (SCOPE), Vellore Institute of Technology, Chennai Campus, Vandalur Kelambakkam Road, Chennai 600127, India.
    Venkatesh, Sridharan Naveen
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Sugumaran, Vaithiyanathan
    School of Mechanical Engineering (SMEC), Vellore Institute of Technology, Chennai Campus, Vandalur Kelambakkam Road, Chennai 600127, India.
    Prabhakaranpillai Sreelatha, Anoop
    Sustainable Mobility Automobile Research Technology (SMART) Center, Department of Electronics and Communication Engineering, Amrita Vishwa Vidyapeetham, Amritapuri, India.
    Mahamuni, Vetri Selvi
    Department of Project Management, Mettu University, P.O. Box: 318, Metu, Ethiopia.
    Enhancing Tire Condition Monitoring through Weightless Neural Networks Using MEMS-Based Vibration Signals2024In: Journal of Engineering, ISSN 2314-4904, E-ISSN 2314-4912, article id 1321775Article in journal (Refereed)
    Abstract [en]

    Tire pressure monitoring system (TPMS) has a critical role in safeguarding vehicle safety by monitoring tire pressure levels. Keeping the accurate tire pressure is necessary for confirming comfortable driving and safety, and improving fuel consumption. Tire problems can result from various factors, such as road surface conditions, weather changes, and driving activities, emphasizing the importance of systematic tire checks. This study presents a novel method for tire condition monitoring using weightless neural networks (WNN), which mimic neural processes using random-access memory (RAM) components, supporting fast and precise training. Wilkes, Stonham, and Aleksander Recognition Device (WiSARD), a type of WNN, stands out for its capability in classification and pattern recognition, gaining from its ability to avoid repetitive training and residual formation. For vibration data acquisition from tires, cost-effective micro-electro-mechanical system (MEMS) sensors are employed, offering a more economical solution than piezoelectric sensors. This approach yields a variety of features, such as autoregressive moving average (ARMA), statistical and histogram features. The J48 decision tree algorithm plays a critical role in selecting essential features for classification, which are subsequently divided into training and testing sets, crucial for assessing the WiSARD classifier’s efficacy. Hyperparameter optimization of the WNN leads to improved classification accuracy and shorter computation times. In practical tests, the WiSARD classifier, when optimally configured, achieved an impressive 97.92% accuracy with histogram features in only 0.008 seconds, showcasing the capability of WNN to enhance tire technology and the accuracy and efficiency of tire monitoring and maintenance.

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  • 2.
    Asplund, Matthias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics. Trafikverket, Maintenance & Environment, Luleå, Sweden.
    Söderström, Pär
    SJ AB, Rolling Stock Division, Stockholm, Sweden.
    Field Validation of Force Response from Defective Wheel2022In: CM 2022 - 12th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Conference Proceedings / [ed] Paul Meehan; Wenyi Yan; Peter Mutton; Jerome Pun, International Conference on Contact Mechanics of Wheel / Rail Systems , 2022, p. 444-448Conference paper (Other academic)
  • 3.
    Bodin, Anders
    Luleå University of Technology.
    Tracked vehicles - the influence of design parameters on the tractive performance in deep snow1999In: Tribologia : Finnish Journal of Tribology, ISSN 0780-2285, Vol. 18, no 3, p. 6-12Article in journal (Refereed)
    Abstract [en]

    A new tracked vehicle has been developed for studying the influence of different vehicle parameters on mobility in soft terrain, particularly on muskegs and in deep snow. The vehicle is skid steered with a hydrostatic transmission, driven by a five-cylinder diesel engine. The vehicle makes it possible to vary several design parameters in the field, and it is equipped with transducers to measure the vehicle trust, track motion resistance, belly resistance, drawbar pull, the trim angle of the vehicle and the slip between the tracks and snow.

  • 4.
    Bouyssou, Anne
    et al.
    Luleå University of Technology, Department of Social Sciences, Technology and Arts, Humans and Technology.
    Baumler, Raphaël
    World Maritime University, Malmö, Sweden.
    Öhrwall Rönnbäck, Anna
    Luleå University of Technology, Department of Social Sciences, Technology and Arts, Humans and Technology.
    Complex Systems Design: Sustainability Challenges for Shipbuilding2023In: Proceedings of the Design Society, ICED 2023, Cambridge University Press , 2023, Vol. 3, p. 1027-1036Conference paper (Refereed)
    Abstract [en]

    Ships are complex technical systems resulting from large scale and scope projects in which integration plays a key role, particularly because trade-offs have to be made between conflicting objectives. Merchant ships are usually built with a perspective of twenty-five years of service. Ship owners detail their requirements and ship specifications in line with their strategy to remain competitive on specific segments of the shipping markets. Ships serve and organize global trade flows. The rise in environmental regulations and technological changes generate unprecedented uncertainties for ship owners. Ships do not follow the usual systems engineering process, as there is no full-scale prototyping. Rules and standards deeply influence the design of ships and limit the possibilities to 'think outside the box'. The purpose of this paper is to present environmental drivers relating to the operation of the ship which have, or will have, an influence on the way it is designed.

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  • 5.
    Casselgren, Johan
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Rosendahl, Sara
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Engström, Niclas
    LKAB, SE-981-86 Kiruna, Sweden.
    Grönlund, Ulrika
    Autoliv Sverige AB, Active Saftey Tech Center, Linköping, Sweden.
    Evaluation of velocity and curvature dependence for roadgrip measured by low lateral slip2017In: International Journal of Vehicle Systems Modelling and Testing, ISSN 1745-6436, E-ISSN 1745-6444, Vol. 12, no 1/2, p. 1-16Article in journal (Refereed)
    Abstract [en]

    Roadgrip is an important parameter for vehicle testing and road maintenance. Therefore, an evaluation of the velocity and curvature effects on roadgrip measurement was performed on asphalt roads and on two ice tracks using the continuous roadgrip apparatus RT3 Curve. The aim was to find suitable driving patterns for measurements on public roads and test tracks to ensure the repeatability of roadgrip measurements. During the evaluation, it was concluded that in order to achieve a reliable roadgrip value, regardless of road conditions, the radius of curvature should not be less than 20 m. The velocity dependency of the RT3 Curve is different for the two road conditions, with the measurements on ice being much more sensitive to velocity changes than the measurements on the dry asphalt.

  • 6.
    Chen, Quan
    et al.
    State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, China.
    Xu, Fanfan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, China.
    Zong, Peijie
    State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, China.
    Song, Fanhao
    State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
    Wang, Bo
    State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, China; Sinopec Dalian Research Institute of Petroleum and Petrochemicals, China Petrochemical Corporation, Dalian 116045, China.
    Tian, Yuanyu
    State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, China; Shandong Engineering and Technology Research Center of High Carbon Low Carbonization, China University of Petroleum (East China), Qingdao 266580, China.
    Wu, Fengchang
    State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
    Zhao, Xiaoli
    State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
    Qiao, Yingyun
    State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, China; Shandong Engineering and Technology Research Center of High Carbon Low Carbonization, China University of Petroleum (East China), Qingdao 266580, China.
    Influence of CaO on the thermal kinetics and formation mechanism of high value-added products during waste tire pyrolysis2022In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 436, article id 129220Article in journal (Refereed)
    Abstract [en]

    There is a lack of detailed research on the production of isoprene and D-limonene by solid base-catalysed thermal depolymerization of waste tires (WTs). This work aimed to investigate the thermal decomposition characteristics, reaction kinetics, high value-added products production and potential mechanisms during WT pyrolysis in the presence of calcium oxide (CaO) via Thermogravimetry-Fourier Transform Infrared spectrometer (TG-FTIR) and Pyrolyzer-Gas Chromatography/Mass spectrometry (Py-GC/MS). The results obtained from TG indicated that CaO accelerated depolymerization in terms of reducing the reaction temperature, which is also reflected in the kinetic parameters. It can be found that the content of D-limonene increased by 13.76% and that of isoprene increased by 37.57%, which were attributed to differences in the depolymerization mechanisms in the presence of CaO. Furthermore, CaO had a profound impact on desulfurization by reducing benzothiazole, sulfoacid, and thiophene. The potential catalytic mechanisms of isoprene and D-limonene production and desulfurization were also proposed. This work deepens the understanding of the catalytic pyrolysis of WT under CaO and unambiguously demonstrates the great potential of CaO in enhancing isoprene and D-limonene production, providing new insight for the cleaner production of high value-added products from WT.

  • 7.
    Christoffersson, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Safe Configurable Maps for Off-Road Sites: Proposed methods for safe and efficient map updates for autonomous trucks2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Autonomous vehicle technology is advancing at a very high pace and self-driving trucks on control-tower operated work sites is already a reality. These autonomous trucks need a highly accurate map of the surroundings for operation and navigation, and it is of great importance to be able to update that map with the ever-changing off-road work site. The autonomous fleet examined have to stop for every update of the site map, which induces unnecessary downtime when updating the site map frequently. The purpose of this work is to contribute to the development of safe configurable maps for autonomous vehicles on off-road sites by identifying and analyzing different map updating methods, proposing the best one, and suggesting how to implement it for this project's case. The result was five different map updating methods, which were evaluated with respect to efficiency and safety. Efficiency was evaluated by comparing total fleet downtime of the proposed solutions with the existing situation. Safety was evaluated by doing a fault tree analysis (FTA) for each proposed solution and comparing the relative size of the fault trees. Proposed Solution III using map tiles was chosen as the most appropriate method to implement for this project's case because it is both efficient and relatively simple. It divides the site map with a grid into smaller rectangular maps and only needs to stop vehicles which are inside the updated tile. The rest of the fleet is able to replace that tile parallel to operation and, therefore, total fleet downtime is significantly reduced. By reaching the stated goal, this work is in line with its original purpose and has contributed to the development of safe configurable maps for autonomous vehicles on off-road sites.

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  • 8.
    Elarbi, Ezzeddin M.
    et al.
    The University of Tripoli, Department of Aeronautical Engineering, Tripoli-Libya.
    Laila, Dina Shona
    The Futures Institute, Coventry University Unit 10, Coventry CV1 2TL, the UK.
    Horri, Nadjim M.
    Aerospace Engineering, Coventry University Priory Street, Coventry, the United Kingdom, CV1 5FB.
    Gain-scheduled linear-quadratic-regulator synthesis for the centre of gravity variations of Boeing 747-100 longitudinal modes2022In: International Journal of Advanced Technology and Engineering Exploration (IJATEE), ISSN 2394-5443, Vol. 9, no 92, p. 868-887Article in journal (Refereed)
  • 9.
    Elgström, Nils-Åke
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Utveckling av fordonschassi till transportfordon2024Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis describes how product development can be achieved for the chassis of a transport vehicle. Freno Air, a Swedish company that is a market leader in making customized chassis solutions and air suspensionsystems for light transport vehicles, needed to develop their product Eurochassi to make it more competitive. The purpose of the product development was to make the Eurochassi more modular and to ensure that the manufacture of the product would be more cost-effective in terms of material utilization, production costs, and assembly costs. As a complete product development of the entire product was not possible within the timeframe of the project, only the chassis frame was investigated. The theory took inspiration from Ulrich and Eppinger’s product development process. Based on the theory, customer needs were identified to outline the requirements and wishes for the new generation Eurochassi. The results from identifying customer needs were used to create the requirements specification. During the concept generation phase, six new concepts for the chassis profile were created. For the selected concept, an analysis was performed on a current chassis frame to understand how it behaves under different loads. A new chassis frame was tested with different dimensions, where height, width, and thickness were varied to compare against the current chassis frame. The results provided a basis for determining which dimensions could be used for the next generation chassis frame. Only individual chassis frames were examined with load and not when they were joined togheter, as this was not part of the project. Assembling these concept examples showed that the next-generation Eurochassi can be manufactured in a more modular and cost-effective way.

  • 10.
    Falk, Mathias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Almgren, Stiven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Active Cooling Unit for Electrical Storage System2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Electro mobility is developing in a rapid pace. Volvo Penta and The Volvo Group are developing hybrid and fully electric solutions for a more sustainable future. One of the biggest limitations can be found in the batteries and its capacity affecting both power and range. Temperature management for batteries is important for a sustainable battery usage, if they are not used within the correct operating temperatures there will be both a performance and lifetime decrease. This report will handle a product development project, from idea to prototype build and final production proposition. Finding the best and most compatible cooling solution for Volvo and keeping the battery operating temperature within the boundaries given from the battery suppliers. The cooling solution includes the Active Cooling Unit, system layouts for combined cab climate and Electrical Storage System temperature management, including heating possibilities. The system is dimensioned of cooling 8 kW at 48°C ambient or coolant at 52°C with a fully operating system.

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  • 11.
    Galvez, Antonio
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics. Tecnalia, Basque Research and Technology Alliance (BRTA), Derio, Spain.
    Galar, Diego
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics. Tecnalia, Basque Research and Technology Alliance (BRTA), Derio, Spain.
    Seneviratne, Dammika
    Tecnalia, Basque Research and Technology Alliance (BRTA), Derio, Spain.
    A Hybrid Model-Based Approach on Prognostics for Railway HVAC2022In: IEEE Access, E-ISSN 2169-3536, Vol. 10, p. 108117-108127Article in journal (Refereed)
    Abstract [en]

    Prognostics and health management (PHM) of systems usually depends on appropriate prior knowledge and sufficient condition monitoring (CM) data on critical components’ degradation process to appropriately estimate the remaining useful life (RUL). A failure of complex or critical systems such as heating, ventilation, and air conditioning (HVAC) systems installed in a passenger train carriage may adversely affect people or the environment. Critical systems must meet restrictive regulations and standards, and this usually results in an early replacement of components. Therefore, the CM datasets lack data on advanced stages of degradation, and this has a significant impact on developing robust diagnostics and prognostics processes; therefore, it is difficult to find PHM implemented in HVAC systems. This paper proposes a methodology for implementing a hybrid model-based approach (HyMA) to overcome the limited representativeness of the training dataset for developing a prognostic model. The proposed methodology is evaluated building an HyMA which fuses information from a physics-based model with a deep learning algorithm to implement a prognostics process for a complex and critical system. The physics-based model of the HVAC system is used to generate run-to-failure data. This model is built and validated using information and data on the real asset; the failures are modelled according to expert knowledge and an experimental test to evaluate the behaviour of the HVAC system while working, with the air filter at different levels of degradation. In addition to using the sensors located in the real system, we model virtual sensors to observe parameters related to system components’ health. The run-to-failure datasets generated are normalized and directly used as inputs to a deep convolutional neural network (CNN) for RUL estimation. The effectiveness of the proposed methodology and approach is evaluated on datasets containing the air filter’s run-to-failure data. The experimental results show remarkable accuracy in the RUL estimation, thereby suggesting the proposed HyMA and methodology offer a promising approach for PHM.

  • 12.
    Gavelin, Johan
    Luleå University of Technology, Department of Social Sciences, Technology and Arts.
    Flytande Förarmiljö: Undersökning av möjligheter till förbättring av förarmiljön i Stridsbåt 90H2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    För att förbättra förarmiljön i Stridsbåt 90 H (CB90 H) skapades en process baseradpå IDEO.org med faser för att analysera nuvarande lösning, identifiera problem samtlösa dessa problem. Genom enkät, intervju, workshops, fokusgrupper ochdeltagande observation med en mindre grupp väldigt erfarna användare kunde fleraproblem ringas in. För att behandla dessa problem användes teori kring kognition, såsom gestaltlagar, kognitiva processer och kognitiv feedback. Även relevantastandarder för förarmiljöer i fartyg samt ergonomi tas upp. Teorin kombineradessedan med de tidigare nämnda metoderna för att komma fram till konkretalösningar. När det fanns en bra uppfattning om hur de olika instrumenten ochreglagen skapades koncept utifrån en egen metod. Metoden är en graf som plottarvikten av synlighet mot vikten av tillgänglighet. Varje enskilt instrument och reglageplaceras därefter ut på grafen där dess synlighet och tillgänglighet motsvaras.Resultatet visade att många instrument var överflödiga för de uppgifter som tillhörföraren och att flera andra placerats ogenomtänkt. Genom att använda grafentillsammans med teorin och standarderna skapades en ny layout för förarens reglageoch instrument. En enkel visualisering skapades utifrån en konstruktionsfil. Slutligendiskuteras arbetets, resultat, relevans och trovärdighet. 

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  • 13.
    Giacomini, Enrico
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Nikolakopoulos, George
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Drones for Planetary Exploration: Modeling Challenges2022In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå: Luleå tekniska universitet, 2022Conference paper (Other academic)
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  • 14.
    Gustavsson, T.
    et al.
    Department of Earth Sciences, University of Gothenburg, Sweden.
    Mostafavi, T.
    Klimator AB, Sweden.
    Bogren, V.
    Klimator AB, Sweden.
    Casselgren, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    AHEAD – A new technology for detection of road conditions2022Conference paper (Refereed)
  • 15.
    Haluska, Jakub
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Västanälv, Jim
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Papadimitriou, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Nikolakopoulos, George
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Soft Pneumatic Actuated Morphing Quadrotor: Design and Development2022In: 2022 30th Mediterranean Conference on Control and Automation (MED), IEEE, 2022, p. 475-480Conference paper (Refereed)
    Abstract [en]

    The majority of the aerial robots scientific literature investigates methods to create fully automated solutions using fixed-frame multi-rotors. However, the ability of the Micro Aerial Vehicles (MAVs) to alter their structure and adapt to various constraints posed by the environment remains unexplored. Aerial robotic platforms that can alter their shape in-flight can increase their potential value and extend the range of applications. It is essential to develop and deploy such platforms which can effectively address the missing elements for exploring previously unreachable locations. This article deals with a novel reconfigurable quadrotor whose arms are based on Soft Pneumatic Actuators (SPA) from a design, analysis, and development point of view. Simulation analysis and experimental results are provided to showcase the potential of such designs that integrate soft actuators with the traditional fixed-frame MAVs designs. © 2022 IEEE.

  • 16.
    Jena, Jajati K.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics. Cyient Limited, Hyderabad, India.
    Verma, Ajit K.
    Western Norway University of Applied Sciences, Haugesund, Norway.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ajit, Srividya
    Indian Institute of Technology Bombay, Mumbai, India.
    A Statistical Approach to Estimate Severe Accident Vehicle Collision Probability Inside a Multi-lane Road Tunnel with Unidirectional Traffic Flow2024In: Reliability Engineering for Industrial Processes / [ed] P. K. Kapur; Hoang Pham; Gurinder Singh; Vivek Kumar, Springer Nature, 2024, Vol. Part F2569, p. 381-397Chapter in book (Other academic)
  • 17.
    Khan, Saad Ahmed
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Rantatalo, Matti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Asplund, Matthias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics. Trafikverket, 972 42 Luleå, Sweden.
    Wheel-rail squeal sound reduction using top of rail friction modifier: a case study2020In: International Journal of COMADEM, ISSN 1363-7681, Vol. 23, no 1, p. 69-76Article in journal (Refereed)
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  • 18.
    Kramar, Vadim
    et al.
    Oulu University of Applied Sciences, Oulu, Finland.
    Nikolakopoulos, George
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Roning, Juha
    University of Oulu, Oulu, Finland.
    Tomasello, Filippo
    University Giustino Fortunato, Benevento, Italy.
    Urban Air Mobility Overview - the European Landscape2021In: Proceedings of the 30th Conference of Open Innovations Association FRUCT / [ed] Sergey Balandin, IEEE , 2021, p. 99-106Conference paper (Refereed)
    Abstract [en]

    Future small aircraft systems, including those having a pilot on-hoard, remotely operated or piloted, and fully autonomous, will he capable of operating in often unstructured and dynamic environments in a safe and efficient manner and simultaneously work towards assigned mission objectives without being extensively controlled or continuously supervised by human operators. Air is a third dimension to the traditional transportation modalities and mobility solutions that typically had not been earlier considered as a part of Smart City planning. And in order to foster its enabling this paper gives an introductory overview of Urban Air Mobility and its elements. The overview includes the historical retrospective, the observation of European initiatives and legislation, the statements on the standardisation effort, as well as clarification of relevant terms and key elements of Urban Air Mobility available at the time of work on this publication.

  • 19.
    Kristoffersson, Ida
    et al.
    Mid Sweden University, Department of Communication, Quality Management, and Information Systems, 851 70 Sundsvall, Sweden.
    Große, Christine
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Digital Services and Systems. Mid Sweden University, Department of Communication, Quality Management, and Information Systems, 851 70 Sundsvall, Sweden.
    Olsson, Leif
    Mid Sweden University, Department of Communication, Quality Management, and Information Systems, 851 70 Sundsvall, Sweden.
    Traffic safety versus accessibility: Investigating resistance against speed limit reductions2024In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 179, article id 103920Article in journal (Refereed)
    Abstract [en]

    For traffic safety reasons, Sweden has lowered speed limits on major roads that lack directional separation of traffic. For some of these roads, regional authorities, municipalities, and other local stakeholders have sent appeals to the government opposing the implemented speed limit reductions. The appeals have mainly referred to negative effects on regional development and have suggested that the speed limit reductions be abandoned. This paper identifies the characteristics of roads where appeals against speed limit reductions have been filed and where local stakeholders claim that speed limit reductions are a threat to accessibility and regional development. The results of logistic regression modelling show that appeals are more likely for speed limit reductions on long road sections, on European roads, and in areas with a state university, and less likely in areas with high population density and areas defined as vulnerable by the Swedish Agency for Economic and Regional Growth. We investigated these policy conflicts using frame theory. In this paper, we identify two policy frames: speed limits for traffic safety and speed limits for regional development. These two policy frames are related to different views on how to best strive towards regional accessibility and safety goals in remote areas. The different views are likely not easily aligned by more information or facts since they concern deeper questions, such as what constitutes basic accessibility of good quality and how large risks are acceptable on the road network. This study thus uncovers not only a policy disagreement but a policy controversy in the Swedish context.

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  • 20.
    Lasslberger, M.
    et al.
    Institute for Design and Control of Mechatronical Systems, Johannes Kepler University Linz, Linz, Austria.
    Gruenbacher, E.
    Electrical Engineering Department, Imperial College London, London, UK.
    Laila, Dina Shona
    Institute for Design and Control of Mechatronical Systems, Johannes Kepler University Linz, Linz, Austria.
    Data based modeling of a PEM fuel cell for control design purposes2008In: Proceedings of the 2008 IEEE International Conference on Control Applications, Institute of Electrical and Electronics Engineers (IEEE), 2008, p. 347-352Conference paper (Refereed)
  • 21.
    Li, Songyu
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Vision based perception systems for unmanned forestry machines2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    After years of continuous development in the past decades, the field of forest production has achieved a notable degree of mechanization. Nonetheless, the unceasing demand for increased productivity in forestry operations continues to drive the rapid expansion of forestry automation. Critical aspects of forest production, including activities such as harvesting, forwarding, seedling planting, and soil preparation, hold significant potential for improved automation. These advancements promise numerous advantages, such as heightened production efficiency, reduced environmental impact, reduced operational costs, and the creation of a more favourable work environment. Beyond fostering industrial progress, such innovations could also make a positive contribution to the sustainable development of forestry.

    Forestry operations take place in intricate natural forest environments, rendering the automation of these processes complex and challenging. To realize full automation of forest machines, it is imperative to equip them with environmental awareness and cognitive capabilities. This can be achieved by integrating advanced imaging sensors with sophisticated algorithms, thereby enabling forest machinery to possess a vision system. By utilizing both novel and existing solutions for object detection, positioning, categorization, and status analysis within the machine's surroundings, combined with intelligent decision-making and control mechanisms, forest machinery can attain a higher degree of operational automation.

    This thesis primarily focuses on the development, deployment, and validation of vision systems on an unmanned forestry machine platform, with a special emphasis on the prototype development of essential features that are still manually executed in contemporary forestry operations. These features include forest terrain obstacle detection, roundwood pose estimation, automated selection of seedling planting locations, and autonomous obstacle avoidance for mounders.

    In this thesis, vision systems rooted in color and stereo camera sensing are designed and deployed on an unmanned forest machinery platform. These systems encompass the following key functionalities:

    •             A precise positioning system for detecting forest terrain obstacles, such as stones and stumps, using stereo camera data in conjunction with deep learning techniques.

    •             Localization and pose estimation capabilities for ground logs, leveraging stereo cameras and deep learning.

    •             An analysis of the planning area for obstacle detection, along with the extraction of feasible planting zones for establishing seedling planting locations.

    •             The development of an automated obstacle avoidance system for forestry mounders, powered by visual solutions.

    Through rigorous testing in real-world scenarios spanning logging, loading, planting, and site preparation, this paper demonstrates the feasibility and practicality of enhancing the level of automation in forest machinery operations through the integration of vision systems. It culminates in the creation of tangible and efficient functional prototypes, leading towards a new era of automation in the field of forestry.

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  • 22.
    Lidgren, Albin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Concept Study and Design of a New Torque Calibration Rig2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When buying a new car today, the customer often expects to get a vehiclewith high quality. Each vehicle or engine should therefore be checked toassure quality. The same goes for clutches and couplings. A powerful enginebecomes useless when a clutch slips. Reliable torque measurement istherefore essential to the automotive industry. The herewith Bachelor thesisproposes a new torque calibration rig for online torque measurement in couplingapplications.The concept encompasses a servo motor with its associated electronics, agearbox to create the high torques (3 kNm), a reference torque transducer,and mounting elements or adapters. From the concept generation phase, thethesis includes CAD-models of the torque calibration rig with mathematicalmodels leading to the calculation of the measurement uncertainty of the calibrationsystem.This work was performed at BorgWarner PowerDrive Systems AB in Landskronaduring eight weeks; the two remaining weeks were completed in Lulea.

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  • 23.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Enoksson, Ola
    Trafikverket, Luleå, Sweden.
    Hojsten, Tommy
    Trafikverket, Luleå, Sweden.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Southeast University, Nanjing, China.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Numerical Analysis of High-Speed Train Induced Aerodynamic Load on Noise Barrier Considering Wind Effect2023In: Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2 / [ed] Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt, Springer, 2023, Vol. 2, p. 332-341Conference paper (Refereed)
    Abstract [en]

    Along the high-speed railway lines, the noise barriers need to be installed to protect nearby inhabitants from noise pollution caused by the running trains. When a high-speed train passes through the noise barriers, due to the blocking effect of noise barrier on air movement, transient train-induced aerodynamic pressure will increase significantly. Field measurement and computational fluid dynamics (CFD) simulation are main ways to study the train-induced aerodynamic pressure on the noise barriers. Due to the complexity of the environmental conditions in field test, however, it is difficult to take into account the wind effects on measurement results. Based on CFD simulation, in this paper, the aerodynamic effects on noise barrier from high-speed trains was simulated by applying the wind flow in the opposite direction to the train running. Influences of train speed and distance from noise barrier to track centre on such aerodynamic pressure were analysed. In addition, by applying the wind flow perpendicular to the longitudinal of train body, the effect of cross wind on the train-induced aerodynamic pressure was evaluated. Results show that pressure magnitude on the noise barriers increases non-linearly with the train speed. There is good nonlinear relationship between the pressure and the square of the distance to track centre. Cross wind increases the magnitude of positive pressure and makes the duration of high-pressure zone longer and absolute value of negative pressure peak decreases. There is a coupling effect of cross wind effect and train-induced aerodynamic effect on noise barriers. 

  • 24.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, 211189, Nanjing, PR China.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    A review on aerodynamic load and dynamic behavior of railway noise barriers when high-speed trains pass2023In: Journal of Wind Engineering and Industrial Aerodynamics, ISSN 0167-6105, E-ISSN 1872-8197, Vol. 239, article id 105458Article in journal (Refereed)
    Abstract [en]

    Noise barriers need to be installed along high-speed railway lines to protect nearby inhabitants from the noise pollution caused by the running of high-speed trains (HSTs). The vertical noise barrier is the main structural type. However, when an HST passes through the noise barriers sited along the track, significant and transient aerodynamic pressure will act on the surface of the noise barriers, resulting in strong dynamic responses and even fatigue damage. Therefore, it is important to determine the train-induced aerodynamic load on the barrier surface and analyze the dynamic behaviors of the noise barriers under such a load for its structural design and to guarantee its safety and durability. This paper is a systematic review of the current literature on the aerodynamic load and dynamic behavior of vertical noise barriers; it includes (1) a summary and analysis of characteristics of such aerodynamic pressure and relevant influencing factors, (2) an introduction to measurement methods of aerodynamic load and relevant pressure models on the surface of noise barriers, and (3) a description of the dynamic response and fatigue analysis of noise barriers under such loads. Finally, potential further studies on this topic are discussed, and conclusions are drawn.

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  • 25.
    Ludwell, William
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Quality Assurance of Saab Aftermarket Replacement Parts2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Saab Automobile AB went into bankruptcy in 2011 ending the production of the iconic Saab cars. There are still many Saab cars on the roads today that continue to need service and repairs. Orio AB has the exclusive rights of the Saab brand to provide the remaining cars with the parts, and technical know-how, to keep the remaining vehicles alive. This thesis will investigate five potentially problematic parts from Orio's Saab catalogue and determine technical solutions to the problems found, either availability issues or copied parts being sold in the general automotive aftermarket, referred to here as aftermarket threat. The parts chosen will be tested in real-life driving conditions and proposed solutions will be found.

    Three of the five parts are classified under aftermarket threat and will be tested against the equivalent available through the general aftermarket, and the remaining two are common failing parts that are unavailable from the OEM supplier. Aftermarket threat parts studied are: Ignition coils for the 2003-2011 Saab 9-3, ignition cassette for the 1998-2010 Saab 9-5 and the jalousie for the automatic gear selector fitting numerous Saabs. No longer available parts studied are: rear lights for the 2010-2011 Saab 9-5 and headlights for the Saab 9-4X.

    The OE and aftermarket ignition coils, and ignition cassette will be tested in various driving situations simulating real life driving conditions, misfires will be logged and compared. The OE jalousie's physical properties will be compared to the aftermarket equivalent to evaluate durability. The rear lights for the 9-5 have an issue with the halogen bulb generating too much heat and melting the socket and housing causing the light to fail. An investigation will be made to evaluate if an LED light could be a viable solution. The last part for testing was to investigate if the EU specification 9-4X headlight could possibly replace the unavailable original US market 9-4X Headlight.

    Results for the ignition coil were inconclusive due to unforeseen problems during testing. The aftermarket ignition cassette tested proved to be inferior to the OE part with initial results showing the the aftermarket cassette caused nearly three times as many misfires compared to the OE part. The aftermarket jalousie was however superior to the OE with the material being softer and more flexible. The rear light problem was resolved by replacing the halogen bulb with an LED and a load resistor. After numerous tests, the 9-4X headlight problem was solved by replacing the headlights with the European equivalent.

    The unforeseen problems that occurred with the ignitions coils was the difficulty of finding actual aftermarket coils. A similar problem was observed with the ignition cassette, but sourcing an actual aftermarket part did not prove to be as much of a challenge. Finding information about the material used for the jalousie proved to be challenging, even the service representative could not provide a more exact material than just TPE. Lack of parts availability for the 9-5 rear light, lead to the LED replacement only being theoretically tested. Calibration of the measuring equipment used on the 9-4X headlights was time consuming. After replacing the equipment testing proved more successful.

  • 26.
    Lundgren, Alex
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Bromssystem för bandgående fordon: Utvecklandet av ett hydrauliskt bromssystem för SIRIUS-våtlamellsbroms2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 27.
    Manarikkal, I.
    et al.
    Future Transport and Cities Research Centre, Coventry University, Coventry, UK.
    Elasha, F.
    Future Transport and Cities Research Centre, Coventry University, Coventry, UK.
    Delli-Carri, A.
    Future Transport and Cities Research Centre, Coventry University, Coventry, UK.
    Laila, Dina Shona
    Future Transport and Cities Research Centre, Coventry University, Coventry, UK.
    Mba, D.
    Department of Technology, De Montford University, Leicester, UK.
    Simplified Single-Stage Planetary Gearbox and Rolling Element Bearings Dynamic Analysis Using Lagrange’s Theorem and Comparison of Vulnerable Frequencies of Vibration2022In: Journal of Vibration Engineering & Technologies, ISSN 2523-3920, Vol. 10, no 1, p. 211-223Article in journal (Refereed)
  • 28.
    Mardiati, R.
    et al.
    School of Electrical Engineering and Informatics, Bandung Institute of Technology, Bandung, 40116, Indonesia, Department of Electrical Engineering, UIN Sunan Gunung Djati Bandung, Bandung, 40614, Indonesia.
    Trilaksono, B. R.
    School of Electrical Engineering and Informatics, Bandung Institute of Technology, Bandung, 40116, Indonesia.
    Wibowo, S. S.
    Department of Civil Engineering, Bandung Institute of Technology, Bandung, 40116, Indonesia.
    Laila, Dina Shona
    School of Mechanical, Aerospace and Automotive Engineering, Coventry University, Coventry, CV1 5FB, UK.
    Modeling Motorcycle Maneuvering in Urban Scenarios Using Markov Decision Process with a Dynamical-Discretized Reward Field2021In: International Journal of Automotive Technology, ISSN 1229-9138, E-ISSN 1976-3832, Vol. 22, no 4, p. 967-977Article in journal (Refereed)
  • 29.
    Marth, Stefan
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Häggblad, Hans-åke
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Oldenburg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    A comparison between Stepwise Modelling and Inverse Modelling methods for characterization of press hardened sheet metals2017In: 6th International Conference Hot Sheet Metal Forming of High-Performance Steel CHS2: June 4-7 2017, Atlanta, Georgia, USA : proceedings / [ed] Mats Oldenburg, Braham Prakash, Kurt Steinhoff, Warrendale, PA: Association for Iron & Steel Technology, AIST , 2017, p. 281-288Conference paper (Refereed)
    Abstract [en]

    The demand for weight reduction of cars has increased the number of press hardened sheet metal parts used in the automotive industry. This leads to an increased demand on the precision of simulations of press hardened sheet metals. An accurate prediction of the post-necking behaviour of materials is therefore needed to increase the precision of computer simulations with large deformations, as for example in forming simulations and crash simulations. Especially fracture simulations of press hardened steel parts with tailored properties have a huge demand on precise material models.

    Inverse modelling is a common engineering tool to characterize the elasto-plastic behaviour of materials.  Taking experimental data, such as force and displacement data, the material model parameters are optimised until the simulated output reaches a target function.  Then inverse modelling is highly time demanding and needs nonlinear hardening material models. 

    Lately a new fast method for post necking characterisation of sheet metals, called the Stepwise Modelling Method (SMM), was presented. This method uses full field measurements to obtain the strain field on the surface of sheet metal tensile specimens.  Furthermore, the stepwise modelling method models an experimental hardening curve in a stepwise process.  This hardening curve is a piecewise linear curve and not restricted to any specific material model.

    In this paper SMM is used to characterize the hardening behaviour for thermally treated boron steel.  These results are compared with the results of inverse modelling. Three different material models are used. The comparison shows a minor deviation in the resulting hardening relations between stepwise modelling and inverse modelling. Since the efficiency is an important factor in product development calculation times are taken into account.  Comparing calculation time using SMM is considerably more efficient than using inverse modelling. Furthermore another advantage of SMM is shown in the fact that the piecewise linear hardening curves can be fitted to almost any material model without computational costs.

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  • 30.
    McGurk, C.
    et al.
    Cummins Engine Co. Ltd, Daventry, UK; Centre for Future Transport and Cities, Coventry University, Coventry, West Midlands, UK.
    Ahmed, H.
    Cummins Engine Co. Ltd, Daventry, UK; Centre for Future Transport and Cities, Coventry University, Coventry, West Midlands, UK.
    Foo, M.
    School of Engineering, University of Warwick, Coventry, West Midlands, UK.
    Pike, A.
    School of Mechanical, Aerospace and Automotive Engineering, Coventry University, Coventry, West Midlands, UK.
    Lu, Q.
    Centre for Future Transport and Cities, Coventry University, Coventry, West Midlands, UK.
    Laila, Dina Shona
    Faculty of Engineering, Universiti Teknologi Brunei, Gadong, Brunei-Muara, Brunei Darussalam.
    A comparative analysis of moving average filter and Kalman filter for large diesel engine test cell back-pressure control2023In: International Journal of Engine Research, ISSN 1468-0874, E-ISSN 2041-3149, Vol. 24, no 7, p. 3186-3196Article in journal (Refereed)
  • 31.
    Mörtsell, Hugo
    Luleå University of Technology, Department of Social Sciences, Technology and Arts.
    Design of an excavator grip: A pilot study and development of an ergonomic Human-Machine interface for excavators2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Excavator industry is developmentally behind many other similar industries. This is, like many parts of these long living machines, true for the controls used to maneuver them. It has few competent control systems that are ergonomic, comfortable, adaptable, durable and intuitive. Existing solutions that fill some of these criteria exist, but the approximate majority of machines in the world lack a good solution and most are equipped with inadequate solutions. 

    The doctrine of Human centered design was applied throughout the pilot study to increase the quality of research and ease finding correlations between instances of information. International standards, Human-machine systems and Anthropometrics were consulted to achieve a result adapted for a larger variety of operators. 

    This thesis consists of the pilot study and prototype development of one such Human-machine-system, more specifically the joystick, or grip as it’s called within the industry. The solution developed is specifically equipped with controls adapted for tiltrotator control. As the grip is developed on behalf of the company engcon, who develops tiltrotators and also the control system including a grip, to offer a complete plug and play solution. 

    The first main objective was performing a pilot study of what is required in the future for excavator grips. Primarily through interviews with excavator operators, but also a benchmarking and a workshop it was determined what must be achieved in terms of technical and ergonomic solutions. 

    The second main objective during the thesis was to create a prototype that achieve a high level in terms of grip form. A form which is comfortable to hold, ergonomic to operate for multiple hours and that is adapted to a larger variety of hand sizes than the competitors. It also required a higher level of stability than the current solution. This shape needed to take internal electronics, ISO-standards and future controls into account. The solution must eventually achieve a high level of manufacturability, of which the groundwork was laid during the thesis, but took lower priority. Further testing is required but results so far seem to point towards this being achieved. 

    This will hopefully post-thesis result in a solution that leads to healthier operators, further enabling female operators entering the field, performing work with higher accuracy and a longer lasting more sustainable product that is intuitive and easy to learn. 

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  • 32.
    Nordin, David
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Design and Evaluatoin of a Carbon Fibre Bus Body2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The automotive industry is in constant development and in recent years the environmental legislations have been getting tougher. The need for lighter and stronger materials has increased according to these changes and composite materials such as carbon fibre reinforced polymers is showing potential of being a solution due to their high specific properties. This thesis is an investigation and design proposal for one way of making a carbon fibre bus body wall structure by the use of pultruded beam elements and a certain number of standardised node elements. This is done to increase the possibility of mass production and possibly lower the manufacturing cost for a carbon fibre structure. The methodology is based on a product development process where a market research as well as a literary study was conducted initially to see what work had been done in the area. Needs were investigated and formulated to a product specification from which concepts was generated using brainstorming methods as well as discussions with bus design engineers at Scania. A number of materials and manufacturing methods was analysed for the node elements and after comparing and scoring different concepts, a carbon fibre node element was chosen. Dimensioning calculations were made based on standardised tests which simulates different driving scenarios. The concept was then designed in 3D-cad and the final weight of the concept was measured to 194 kg. A comparison of the concept with a steel bus was made by the use of the life cycle analysis tool in CES Edupack 2017 which resulted in a difference of 47 tonnes carbon dioxide released for a diesel driven light goods vehicle during the first six years of the lifetime. The overall results show that a carbon fibre bus body might be economically beneficial during the entire lifetime of a bus even though the purchase price is higher.

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  • 33.
    Olausson, Zacharias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Magnusson, Christoffer
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Sensorifiering av grep och rotator på skogsmaskin: Examensarbete för bilsystemsteknik2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
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  • 34.
    Ragnarsson, Albin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    En bättre mätmiljö: Standardisering och användaroptimering avmätsystem för motorprovcell2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is written as part of the thesis requirements for a bachelor of science in Automotive systems at Luleå University of Technology. BAE systems Hägglunds was in need of improved user interface and standardization of their test rigs for drivelines. There was a lack of a naming system for the sensors, formulas for efficiency and heating power as well as the absence of graphical view of the test objects with associated sensors. All of this is important for an efficient development procedure. Also a suggestion on suitable replacement of the mechanical water flow sensor was requested. This report presents the theory around the components and sensors regarding the test rigs, methods for making the decision and finished results. By developing an understanding of the test cell and test subjects, graphical recreations could be created with belonging calculations and documentation. Reading of analog signals and digital CAN-messages made it possible to collect and use the data from the sensors that was requested. By comparing the different flow sensors a of that the inductive flow sensor is most suitable for BAE System Hägglunds was made. The thesis resulted in a chosen naming system which is according to(Element)(Material)_(High/LowTemperature)_(Subject)_(In/Out). Formulas for efficiency and heating power, as well as 6 graphical views, 6 implemented views and 6 Excel documents was made and implemented in the DewesoftX software. The graphical views strongly improved the user interface of the test cell. Because some of the objects are classified they can also be used when presenting the data from testing without giving out more information than necessary. Also to make it easy to see where the sensors are placed and how to install the object in the test cell. This is very useful for BAE Systems Hägglunds that are now expanding their personal that will need basic knowledge of the test cell. 

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  • 35.
    Ram, Sumanth
    et al.
    Predge AB, Västra Varvsgatan 11, SE-97236, Luleå, Sweden.
    Al-Kahwati, Kamal
    Predge AB, Västra Varvsgatan 11, SE-97236, Luleå, Sweden.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems. Predge AB, Västra Varvsgatan 11, SE-97236, Luleå, Sweden.
    Westerberg, Jesper
    Predge AB, Västra Varvsgatan 11, SE-97236, Luleå, Sweden.
    Detection of Bogie Performance Issues using Way-Side Monitoring Systems2022In: Proceedings of the AREMA 2022 Annual Conference, Lanham: American Railway Engineering and Maintenance-of-Way Association (AREMA) , 2022Conference paper (Refereed)
  • 36.
    Reetz, Susanne
    et al.
    Institute of Transportation Systems, German Aerospace Center (DLR), Braunschweig, 38108, Germany.
    Najeh, Taoufik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Groos, Jörn
    Institute of Transportation Systems, German Aerospace Center (DLR), Braunschweig, 38108, Germany.
    Analysis of Local Track Discontinuities and Defects in Railway Switches Based on Track-Side Accelerations2024In: Sensors, E-ISSN 1424-8220, Vol. 24, no 2, article id 477Article in journal (Refereed)
    Abstract [en]

    Switches are an essential, safety-critical part of the railway infrastructure. Compared to open tracks, their complex geometry leads to increased dynamic loading on the track superstructure from passing trains, resulting in high maintenance costs. To increase efficiency, condition monitoring methods specific to railway switches are required. A common approach to track superstructure monitoring is to measure the acceleration caused by vehicle track interaction. Local interruptions in the wheel–rail contact, caused for example by local defects or track discontinuities, appear in the data as transient impact events. In this paper, such transient events are investigated in an experimental setup of a railway switch with track-side acceleration sensors, using frequency and waveform analysis. The aim is to understand if and how the origins of these impact events can be distinguished in the data of this experiment, and what the implications for condition monitoring of local track discontinuities and defects with wayside acceleration sensors are in practice. For the same experimental configuration, individual impact events are shown to be reproducible in waveform and frequency content. Nevertheless, with this track-side sensor setup, the different types of track discontinuities and defects (squats, joints, crossing) could not be clearly distinguished using characteristic frequencies or waveforms. Other factors, such as the location of impact event origin relative to the sensor, are shown to have a much stronger influence. The experimental data suggest that filtering the data to narrow frequency bands around certain natural track frequencies could be beneficial for impact event detection in practice, but differentiating between individual impact event origins requires broadband signals. A multi-sensor setup with time-synchronized acceleration sensors distributed over the switch is recommended.

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  • 37.
    Riström, Anton
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Naronikar, Aditya
    Linköping University.
    CFD and Experimental Study of Refuelling and Venting a Fuel System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In 1999, California Air Resources Board (CARB) implemented a regulation that required all gasoline cars sold in California be fitted with an Onboard Refueling Vapor Recovery System (ORVR). The ORVR system is designed to prevent Volatile Organic Compounds (VOCs) from escaping into the atmosphere during refuelling by storing the gas vapours in a carbon canister. Due to the complex nature of the fuel system, making design changes could have large implications on the ORVR performance of the vehicle. It is therefore desirable to develop a CFD model that can predict the effects of design changes, thereby reducing the need to perform physical tests on each design iteration. This master thesis project was performed at the Fuel Systems department at Volvo Cars in order to help reduce project lead times and product development costs by incorporating CFD as a part of the fuel system development cycle. The CFD results obtained were validated through experimental tests that were also performed as part of this project. In this master thesis project, a CFD model was developed to simulate the refuelling of gasoline for a California specification Volvo XC90 with an OPW-11B pump pistol. The model was set up in STAR-CCM+ using the Eulerian Volume of Fluid model for multiphase flow, the RANS realizable k − ε turbulence model and the two layer all y + wall treatment. The effects of the carbon canister were modelled as a porous baffle interface in the simulations where viscous and inertial resistances of the porous media were adjusted to obtain a desired pressure drop across the canister. This method proved to be a suitable simplification for this study. The effects of evaporation as well as a chemical adsorption model for the carbon canister have been excluded from the project due to time limitations. It was found that the CFD simulations were in good agreement with the experimental results, especially with respect to capturing the overall behaviour of the fuel system during refuelling. It was found that resolving the flow spatially (and temporally) in the filler pipe was a crucial part in ensuring solver stability. A pressure difference between experiment and simulation was also observed as a consequence of excluding evaporation from the CFD model. After the CFD model had been verified and validated, changes to different parts of the fuel system were investigated to observe their effects on ORVR performance. These included changing the recirculation line diameter, changing the carbon canister properties and changing the angle of how the pump pistol was inserted into the capless unit. It was found that the recirculation line diameter is a very sensitive design parameter and increasing the diameter would result in fuel vapour leaking back out into the atmosphere. Similarly, increasing the back pressure by swapping to a different carbon canister would result in the leakage of fuel vapour. On the other hand, insignificant changes in system behaviour were observed when the fuel pistol angle was changed.In 1999, California Air Resources Board (CARB) implemented a regulation that required all gasoline cars sold in California be fitted with an Onboard Refueling Vapor Recovery System (ORVR). The ORVR system is designed to prevent Volatile Organic Compounds (VOCs) from escaping into the atmosphere during refuelling by storing the gas vapours in a carbon canister. Due to the complex nature of the fuel system, making design changes could have large implications on the ORVR performance of the vehicle. It is therefore desirable to develop a CFD model that can predict the effects of design changes, thereby reducing the need to perform physical tests on each design iteration. This master thesis project was performed at the Fuel Systems department at Volvo Cars in order to help reduce project lead times and product development costs by incorporating CFD as a part of the fuel system development cycle. The CFD results obtained were validated through experimental tests that were also performed as part of this project. In this master thesis project, a CFD model was developed to simulate the refuelling of gasoline for a California specification Volvo XC90 with an OPW-11B pump pistol. The model was set up in STAR-CCM+ using the Eulerian Volume of Fluid model for multiphase flow, the RANS realizable k − ε turbulence model and the two layer all y + wall treatment. The effects of the carbon canister were modelled as a porous baffle interface in the simulations where viscous and inertial resistances of the porous media were adjusted to obtain a desired pressure drop across the canister. This method proved to be a suitable simplification for this study. The effects of evaporation as well as a chemical adsorption model for the carbon canister have been excluded from the project due to time limitations. It was found that the CFD simulations were in good agreement with the experimental results, especially with respect to capturing the overall behaviour of the fuel system during refuelling. It was found that resolving the flow spatially (and temporally) in the filler pipe was a crucial part in ensuring solver stability. A pressure difference between experiment and simulation was also observed as a consequence of excluding evaporation from the CFD model. After the CFD model had been verified and validated, changes to different parts of the fuel system were investigated to observe their effects on ORVR performance. These included changing the recirculation line diameter, changing the carbon canister properties and changing the angle of how the pump pistol was inserted into the capless unit. It was found that the recirculation line diameter is a very sensitive design parameter and increasing the diameter would result in fuel vapour leaking back out into the atmosphere. Similarly, increasing the back pressure by swapping to a different carbon canister would result in the leakage of fuel vapour. On the other hand, insignificant changes in system behaviour were observed when the fuel pistol angle was changed. 

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  • 38.
    Rouchitsas, Alexandros
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Virtual Human Characters for Autonomous Vehicle-to-Pedestrian Communication2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Pedestrians base their street-crossing decisions on both vehicle-centric cues, like speed and acceleration, and driver-centric cues, like gaze direction and facial expression. In the future, however, drivers of autonomous vehicles will be preoccupied with non-driving related activities and thus unavailable to provide pedestrians with relevant communicative cues. External human-machine interfaces (eHMIs) hold promise for filling the expected communication gap by providing information about the current state and future behaviour of an autonomous vehicle, to primarily ensure pedestrian safety and improve traffic flow, but also promote public acceptance of autonomous vehicle technology. The aim of this thesis is the development of an intuitive, culture-transcending eHMI, that can support multiple pedestrians in parallel make appropriate street-crossing decisions by communicating pedestrian acknowledgement and vehicle intention. In the proposed anthropomorphic eHMI concept, a virtual human character (VHC) is displayed on the windshield to communicate pedestrian acknowledgement and vehicle intention via gaze direction and facial expression, respectively. The performance of different implementations of the proposed concept is evaluated in the context of three monitor-based, laboratory experiments where participants performed a crossing intention task. Four papers are appended to the thesis. Paper I provides an overview of controlled studies that employed naive participants to evaluate eHMI concepts. Paper II evaluates the effectiveness of the proposed concept in supporting a single pedestrian or two co-located pedestrians make appropriate street-crossing decisions. Paper III evaluates the efficiency of emotional facial expressions in communicating non-yielding intention. Paper IV evaluates the efficiency of emotional and conversational facial expressions in communicating yielding and non-yielding intention. An implementation of the proposed anthropomorphic eHMI concept where a male VHC communicates non-yielding intention via an angry expression, cruising intention via cheek puff, and yielding intention via nod, is shown to be both highly effective in ensuring the safety of a single pedestrian or even two co-located pedestrians without compromising traffic flow in either case, and the most efficient. Importantly, this level of effectiveness is reached in the absence of any explanation of the rationale behind the eHMI concept or training to interact with it successfully.

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  • 39.
    Rouchitsas, Alexandros
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Alm, Håkan
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Communicating Vehicle Non-Yielding Intention via Emotional Facial Expressions: Angry vs. Surprised2022In: Article in journal (Other academic)
  • 40.
    Rouchitsas, Alexandros
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Alm, Håkan
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Ghost on the Windshield: Employing a Virtual Human Character to Communicate Pedestrian Acknowledgement and Vehicle Intention2022In: Information, E-ISSN 2078-2489, Vol. 13, no 9, article id 420Article in journal (Refereed)
    Abstract [en]

    Pedestrians base their street-crossing decisions on vehicle-centric as well as driver-centric cues. In the future, however, drivers of autonomous vehicles will be preoccupied with non-driving related activities and will thus be unable to provide pedestrians with relevant communicative cues. External human–machine interfaces (eHMIs) hold promise for filling the expected communication gap by providing information about a vehicle’s situational awareness and intention. In this paper, we present an eHMI concept that employs a virtual human character (VHC) to communicate pedestrian acknowledgement and vehicle intention (non-yielding; cruising; yielding). Pedestrian acknowledgement is communicated via gaze direction while vehicle intention is communicated via facial expression. The effectiveness of the proposed anthropomorphic eHMI concept was evaluated in the context of a monitor-based laboratory experiment where the participants performed a crossing intention task (self-paced, two-alternative forced choice) and their accuracy in making appropriate street-crossing decisions was measured. In each trial, they were first presented with a 3D animated sequence of a VHC (male; female) that either looked directly at them or clearly to their right while producing either an emotional (smile; angry expression; surprised expression), a conversational (nod; head shake), or a neutral (neutral expression; cheek puff) facial expression. Then, the participants were asked to imagine they were pedestrians intending to cross a one-way street at a random uncontrolled location when they saw an autonomous vehicle equipped with the eHMI approaching from the right and indicate via mouse click whether they would cross the street in front of the oncoming vehicle or not. An implementation of the proposed concept where non-yielding intention is communicated via the VHC producing either an angry expression, a surprised expression, or a head shake; cruising intention is communicated via the VHC puffing its cheeks; and yielding intention is communicated via the VHC nodding, was shown to be highly effective in ensuring the safety of a single pedestrian or even two co-located pedestrians without compromising traffic flow in either case. The implications for the development of intuitive, culture-transcending eHMIs that can support multiple pedestrians in parallel are discussed.

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  • 41.
    Rouchitsas, Alexandros
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Alm, Håkan
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Smiles and Angry Faces vs. Nods and Head Shakes: Facial Expressions at the Service of Autonomous Vehicles2023In: Multimodal Technologies and Interaction, E-ISSN 2414-4088, Vol. 7, no 2, article id 10Article in journal (Refereed)
    Abstract [en]

    When deciding whether to cross the street or not, pedestrians take into consideration information provided by both vehicle kinematics and the driver of an approaching vehicle. It will not be long, however, before drivers of autonomous vehicles (AVs) will be unable to communicate their intention to pedestrians, as they will be engaged in activities unrelated to driving. External human–machine interfaces (eHMIs) have been developed to fill the communication gap that will result by offering information to pedestrians about the situational awareness and intention of an AV. Several anthropomorphic eHMI concepts have employed facial expressions to communicate vehicle intention. The aim of the present study was to evaluate the efficiency of emotional (smile; angry expression) and conversational (nod; head shake) facial expressions in communicating vehicle intention (yielding; non-yielding). Participants completed a crossing intention task where they were tasked with deciding appropriately whether to cross the street or not. Emotional expressions communicated vehicle intention more efficiently than conversational expressions, as evidenced by the lower latency in the emotional expression condition compared to the conversational expression condition. The implications of our findings for the development of anthropomorphic eHMIs that employ facial expressions to communicate vehicle intention are discussed.

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  • 42.
    Sandlund, David
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Häggblad, Anton
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Utveckling av torsionsstavsupphängning på Stridsfordon 90: I samarbete med BAE Systems Hägglunds Örnsköldsvik2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 43.
    Silla, Anne
    et al.
    VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044 VTT, Espoo, Finland.
    Leden, Lars
    VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044 VTT, Espoo, Finland.
    Rämä, Pirkko
    VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044 VTT, Espoo, Finland.
    Scholliers, Johan
    VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044 VTT, Espoo, Finland.
    van Noort, Martijn
    TNO, PO Box 49, 2600 AA, Delft, The Netherlands.
    Morris, Andrew
    Loughborough Design School, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
    Hancox, Graham
    Loughborough Design School, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
    Bell, Daniel
    FACTUM Chaloupka & Risser OG, Danhausergasse 6/4, 1040, Vienna, Austria.
    A headway to improve PTW rider safety within the EU through three types of ITS2018In: European Transport Research Review, ISSN 1867-0717, E-ISSN 1866-8887, Vol. 10, article id 18Article in journal (Refereed)
  • 44.
    Sollén, Sofia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Casselgren, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Friction information from floating car data2022Conference paper (Refereed)
  • 45.
    Sowman, J.
    et al.
    Energy Technology Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
    Box, S.
    Transportation Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
    Wong, A.
    Transportation Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
    Grote, M.
    Transportation Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
    Laila, Dina Shona
    School of Mechanical, Aerospace and Automotive Engineering, Coventry University, Coventry, CV1 2TL, UK.
    Gillam, G.
    Transportation Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
    Cruden, A. J.
    Energy Technology Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
    Preston, J. M.
    Transportation Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, UK.
    Fussey, P.
    Engine Control and Calibration, Ricardo Ltd, Shoreham-by-Sea, West Sussex, BN43 5FG, UK.
    In-use emissions testing of diesel-driven buses in Southampton: is selective catalytic reduction as effective as fleet operators think?2018In: IET Intelligent Transport Systems, ISSN 1751-956X, E-ISSN 1751-9578, Vol. 12, no 6, p. 521-526Article in journal (Refereed)
  • 46.
    Sowman, J.
    et al.
    Energy Technology Research Group, University of Southampton, UK.
    Laila, Dina Shona
    Energy Technology Research Group, University of Southampton, UK.
    Cruden, A. J.
    Energy Technology Research Group, University of Southampton, UK.
    Fussey, P.
    Engine Control and Calibration, Ricardo UK Ltd, UK.
    Nonlinear Model Predictive Control for Cold Start Selective Catalytic Reduction2015In: / [ed] David Muñoz de la Peña; Daniel Limón, Elsevier B.V. , 2015, Vol. 48, no 23, p. 471-476Conference paper (Refereed)
  • 47.
    Woldu, Yared
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Fritz, Anton
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Using CFD to analyze thermal and optical influence on a zero pressure balloon at floating condition2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The ability to control the trajectory and understanding the atmospheric effects on the flight performance of a scientific high altitude balloon has long been an aspiring ambition. This thesis work analyses the thermal and optical environments at float using the simulation software, ANSYS FLUENT. The objectives for this thesis were to evaluate how the solar angle, sunshine factor and the ground emissivity altered the altitude for the balloon during floating condition in Steady-state simulations. A transient simulation was conducted to evaluate the diurnal cycle effects on the altitude of the balloon. The understanding of how the parameters influence the altitude will make it possible to autonomously route the balloon to desired altitudes where you have a favorable wind direction.

    Performing steady-state simulations showcased the significance of certain parameters. Different solar angles greatly influenced the temperature gradient on the balloon and hence a larger lifting force acted on the balloon when the sun was at its highest point. Varying the cloudiness mostly affected the maximum temperature distribution and did not affect the minimum temperature distribution. The steady-state simulations also indicated a limited but noticeable dependence on the ground emissivity. From the transient simulations it was further enhanced how great of influence the solar angle have, which was illustrated by running diurnal cycles. It was also apparent that there are great differences depending on the seasons. For future applications, it would be of interest to investigate the effects caused by wind velocities in the steady-state case. A comparative analytic solution should be performed in order to validate the simulation results.

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