lnu.sePublications
Change search
Refine search result
12 1 - 50 of 61
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Berggren, Magnus
    et al.
    Blekinge Institute of Technology.
    Nilsson, Kristian
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Agnesson, Helen
    Hedsten, Stefan
    Noise Measurements in Incubators at Neonatal Intensive Care Unit2012In: 19th International Congress on Sound and Vibration 2012 (ICSV 19), Curran Associates, Inc., 2012Conference paper (Other academic)
    Abstract [en]

    The purpose of this study was to investigate the noise properties and levels of common noise sources in a neonatal intensive care unit (NICU) and in particular inside and around an incubator. Many previous studies have been made on noise levels in NICU, frequently focusing on A-weighted sound levels. In this study it was not assumed that infant's hearing follows the same equal loudness curve as adults and hence instead of A-weighting, short time averaged sound spectra in the frequency range 20 Hz to 20 kHz was logged to identify the frequency distribution of specific noise generating events. It was seen that alarms and CPAP air-flow increased the noise level by up to 8 dB outside but was barely noticed inside when considering the un-weighted noise level. However, by analyzing individual frequencies, most events were noticeable inside the incubator. For instance, frequencies above 1 kHz were increased by 10 dB inside and 11 dB outside the incubator when CPAP was turned on. Opening and closing the incubator increased the un-weighted noise level by 8 dB inside and 7 dB outside.

  • 2.
    Campos, Jaime
    et al.
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Kans, Mirka
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Information System Requirements Elicitation for Gravel Road Maintenance: A Stakeholder Mapping Approach2020In: Advances in Asset Management and Condition Monitoring. Smart Innovation, Systems and Technologies: COMADEM 2019 / [ed] Ball A., Gelman L., Rao B., Springer, 2020, p. 377-387Chapter in book (Refereed)
    Abstract [en]

    Gravel road maintenance is a complex endeavour comprising physical, technical and social aspects that have to be considered, and resources to be coordinated. The maintenance requirements are affected by weather conditions, geography, and traffic frequency, but also by the physical properties of the road and the previous maintenance performance. The physical properties and maintenance requirements are area dependent; in Northern Europe, ground frost, for instance, is a problem, while flooding is a problem in East Asia. Understanding the specific context-dependent variables is therefore important when designing a maintenance information system. In this paper, the maintenance information system requirements are identified focusing on the Swedish gravel road ecosystem. The system elicitation process is crucial to be able to specify the requirements of the future system and its users, and in this paper, a stakeholders’ approach is utilized. Different stakeholders are described, including their maintenance related needs, information needs, and roles in the maintenance system. The interdependencies between different stakeholders are also illustrated in an ecosystem diagram. From these descriptions, requirements for computerized maintenance management systems are elicited, and main users are identified. User scenarios are thereafter illustrated using the User Case technique.

  • 3. Claesson, Ingvar
    et al.
    Håkansson, Lars
    Lagö, Thomas
    Zimmergren, Rolf
    Hällerstedt, Göran
    Device and a method for preventing or reducing vibrations in a cutting tool2007Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    An arrangement for reducing vibrations in a tool holder (4) with a cutting tool (3) and has a vibration sensor on the tool holder (4) that is connected to a guide unit (11). The tool holder (4) has further two piezo-electric actuators 14 and 15.

    Under the influence of the vibration sensor (9), the guide unit (11) provides an electric alternating current that is actively guided over time so that the actuators movably affect the tool holder (4) to reduce the vibrations in this. To also be able to dampen transients in the tool holder (4) this is movably connected with a passive dampening arrangement that is independent of the guide unit (11) and that is based on the principle of a springing (8) suspended mass (7). The invention also relates to a method for reducing vibrations. The vibrations in the tool holder are sensed and a corresponding signal is provided to a guide unit that over time provides actively guided signals to the actuators. The tool holder is also passively influenced by a dampening arrangement that is independent of the guide unit.

  • 4. Claesson, Ingvar
    et al.
    Lagö, Thomas
    Håkansson, Lars
    Method and a device for vibration control2004Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A device for vibration control in a machine for internal turning uses a cutting tool supported by a tool holder, and has a control unit, a vibration sensor connectible to the control unit, and an actuator connectible to the control unit. The actuator has an active element, which converts an A.C. voltage supplied by the control unit to the actuator into dimensional changes. The active element is adapted to be embedded in the body of the tool holder, and is adapted to be embedded in such a manner that the dimensional changes impart bending to the body of the tool holder. A method for vibration control in internal turning and a tool holder for internal turning are provided.

  • 5. Claesson, Ingvar
    et al.
    Lagö, Thomas
    Håkansson, Lars
    Method and device for controlling a turning operation2005Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A device increases the surface smoothness of a turned surface. The device comprising a control system with a control unit and an actuator connectible to the control unit and connectible with a tool holder. The actuator in adapted to impart a vibrating motion in the lateral direction to the tool holder. A method will also increase the surface smoothness of a turned surface, comprising the step of controlling the vibrations of the tool holder during turning. The method also comprises the step of imparting a vibrating motion in the lateral direction to the tool holder. Moreover, a turning lathe and a turning tool holder which like the device are designed to generate vibrating motion in the lateral direction.

  • 6. Claesson, Ingvar
    et al.
    Lagö, Thomas
    Håkansson, Lars
    Method and device for vibration control2008Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A device and method for vibration control in a machine for cutting, said machine comprising a cutting tool supported by a tool holder. The device comprises a control unit and converting means which are connectible to the control unit and comprise a vibration sensor and an actuator. The actuator comprises an active element which converts an A.C. voltage supplied by the control unit to the actuator into dimensional changes. Said active element is adapted to be embedded in the body of the tool holder and in such manner that said dimensional changes impart bending to the body of the tool holder.

  • 7. Claesson, Lena
    et al.
    Håkansson, Lars
    Using an Online Remote Laboratory for Electrical Experiments in Upper Secondary Education2012In: International Journal of Online Engineering, ISSN 1868-1646, E-ISSN 1861-2121, Vol. 8, no Special Issue, p. 24-30Article in journal (Refereed)
    Abstract [en]

    The use of remote laboratories in courses at university level has been reported in literature numerous times since the mid 90?s. In this article focus is on activities carried out by teachers and students, at the Upper Secondary School Level, using the remote laboratory VISIR (Virtual Instrument Systems in Reality). The Upper Secondary School, Katedralskolan in Lund, Sweden, cooperate with Blekinge Institute of Technology, Sweden, in a project that concerns the introduction of remote laboratory environment suitable for Upper Secondary School science courses. A remote laboratory in electronics has been introduced and is used as a complement to the traditional workbench in the hands-on laboratory. Significant results from the project are; 1) the great interest shown by the students for the remote experiments, 2) the students appreciation for the fact that it was not simulations but actual real experiments, 3) the remote laboratory is easy to implement for use by both teachers and students and 4) it can be used simultaneously by many students.

  • 8.
    Claesson, Lena
    et al.
    Blekinge institute of technology, Sweden.
    Kans, Mirka
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Nilsson, Kristian
    Blekinge institute of technology, Sweden.
    STEM Education on Equal Terms Through the Flipped Laboratory Approach2021In: Cross Reality and Data Science in Engineering: Proceedings of the 17th International Conference on Remote Engineering and Virtual Instrumentation / [ed] Michael E. Auer, Dominik May, Springer, 2021, p. 46-62Conference paper (Refereed)
    Abstract [en]

    The educational phenomena studied in this paper is remote-controlled physical laboratory environments and their applicability in upper secondary school physics education. In order to gain a better understanding of the situation and needs regarding laboratory activities in the upper secondary school, eight physics teachers were interviewed at six different schools. This revealed that the resources for laboratory activities vary between schools and may be inconsistent with the Swedish National Agency for Education curriculum. Furthermore, 165 upper secondary school students answered a questionnaire survey regarding subject preferences, program choices, views on technology and self-ability, and approach to technology and technology-related situations. The acquired knowledge provides a basis concerning the needs and conditions of teaching and learning within the subject of physics. This new knowledge motivates the development of the Flipped laboratory concept that is introduced in this paper, based on remote-controlled physical laboratories, for upper secondary school.

  • 9.
    Claesson, Lena
    et al.
    Blekinge Institute of Technology, Sweden.
    Lundberg, Jenny
    Linnaeus University, Faculty of Technology, Department of computer science and media technology (CM).
    Zackrisson, Johan
    Blekinge Institute of Technology, Sweden.
    Johansson, Sven
    Blekinge Institute of Technology, Sweden.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Expert Competence in Remote Diagnostics: Industrial Interests, Educational Goals, Flipped Classroom & Laboratory Settings2018In: Online Engineering & Internet of Things: Proceedings of the 14th International Conference on Remote Engineering and Virtual Instrumentation REV 2017, held 15-17 March 2017, Columbia University, New York, USA / [ed] Michael E. Auer & Danilo G. Zutin, Springer, 2018, Vol. 22, p. 438-451Conference paper (Refereed)
    Abstract [en]

    The manufacturing industry are dependent of engineering expertise. Currently the ability to supply the industry with engineering graduates and staff that have an up-to- date and relevant competences might be considered as a challenge for the society. In this paper an education approach is presented where academia - industry - research institutes cooperate around the development and implementation of master level courses. The methods applied to reach the educational goals, concerning expert competence within remote diagnostics, have been on site and remote lectures given by engineering, medical and metrology experts. The pedagogical approach utilized has been flipped classroom. The main results show that academic courses developed in cooperation with industry requires flexibility, time and effort from the involved partners. The evaluation interviews indicate that student are satisfied with the courses and pedagogical approach but suggests more reconciliation meetings for course development. Labs early in the course was considered good, and division of labs at the system and the component level. However further long- term studies of evaluation of impact is necessary.

    Download full text (pdf)
    fulltext
  • 10. Cleasson, Lena
    et al.
    Khan, Imran
    Zackrisson, Johan
    Nilsson, Kristian
    Gustavsson, Ingvar
    Håkansson, Lars
    Chapter 7 – Using a VISIR laboratory to supplement teaching and learning processes in physics courses in a Swedish upper secondary school2013In: IT Innovative Practices in Secondary Schools: Remote Experiments / [ed] O. Dziabenko and J. Garcia-Zubia, Bilbao, Spain: Universidad de Deusto - Dpto. de Publicaciones, 2013Chapter in book (Refereed)
  • 11.
    Eriksson, Kristina
    et al.
    University West, Sweden.
    Chirumalla, Koteshwar
    Mälardalen University, Sweden.
    Myrelid, Paulina
    Mälardalen University, Sweden.
    Ericsson, Mikael
    University West, Sweden.
    Granlund, Anna
    Mälardalen University, Sweden.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Johansson, Daniel
    University West, Sweden.
    Experiences in Running a Professional Course on Digitally-Enabled Production in Collaboration Between Three Swedish Universities2022In: Advances in Transdisciplinary Engineering, Volume 21 / [ed] Ng A.H.C., Syberfeldt A., Hogberg D., Holm M., IOS Press, 2022, Vol. 21, p. 653-664Conference paper (Refereed)
    Abstract [en]

    Needs for new competences and knowledge arise as industry 4.0 evolves in increasingly digitalized production. This development entails that job transformations and future skills need attention from the perspective of industry 5.0, where human and machine find ways of working together to improve production performance. Facing this perspective, one challenge is a growing need for novel lifelong learning initiatives, to meet emerging and altering occupations for the fulfilment of future skill requirements. This challenge is addressed here by portraying a case where three Swedish universities have formed a distinctive collaboration to develop a flexible (i.e. blended) course for professionals, in the subject of Digitally-enabled production. The purpose is to develop a sustainable collaboration between the universities and create a course format on master level addressing lifelong learning for the increasingly digitalized production. The ambition is to increase the impact of the universities respective efforts by sharing resources and utilizing individual specialized expertise to develop a practical and relevant course that can reach a larger target group. The course encompasses industry 4.0 readiness on three levels of production systems; plant-, production cell-, and component level; to adopt a holistic view of digitalization in production. We followed an action research approach for continuously collecting and documenting our experiences during the course development, implementation, and dissemination of the course. Within the frame of action research, an explorative case study describes and analyzes the initiative. The results highlight challenges and opportunities for succeeding with this form of co-produced course. The joint course gives professionals possibilities to work on cases from their own companies with expert supervision from three manufacturing levels to address complex challenges in industry 4.0 implementation. To conclude, the importance of lifelong learning in relation to the human-centric approach of industry 5.0 is emphasized as a future direction.

    Download full text (pdf)
    fulltext
  • 12.
    Gertsovich, Irina
    et al.
    Blekinge Institute of Technology.
    Ström Bartunek, Josef
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Nilsson, Mikael
    Lund University.
    A Novel Methodology for the Interoperability Evaluation of An Iris Segmentation Algorithm2013In: 2013 IEEE Sixth International Conference on Biometrics: Theory, Applications and Systems (BTAS), IEEE, 2013Conference paper (Refereed)
    Abstract [en]

    The performance of an iris recognition system depends greatly on how well the iris segmentation part of the system performs its task. The performance of an iris segmentation algorithm can be evaluated using different criteria and methods. Some of the methods evaluate the performance of the segmentation algorithm based on the performance of the whole iris recognition system. Other methods evaluate the performance of an iris segmentation subsystem independent of the performance of the system's other subsystems. To our knowledge there do not exist a generally accepted method or criteria for the evaluation of the standalone iris segmentation subsystem. This paper proposes a novel methodology to compare the performance of different iris segmentation algorithms, applied to different image datasets in a consistent way. The methodology employs the F1 score and an empirical cumulative distribution function. The implementation of the F1 score estimation, adapted to the iris segmentation task is described. Finally the application of the proposed methodology is demonstrated and discussed.

  • 13.
    Gustavsson, Ingvar
    et al.
    Blekinge Institute of Technology.
    Claesson, Lena
    Blekinge Institute of Technology.
    Nilsson, Kristian
    Blekinge Institute of Technology.
    Zackrisson, Johan
    Blekinge Institute of Technology.
    Garcia, Javier Zubia
    University of Deusto, Spain.
    Hernandez, Jayo Unai
    University of Deusto, Spain.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Ström Bartunek, Josef
    Blekinge Institute of Technology.
    Lagö, Thomas
    Blekinge Institute of Technology.
    Claesson, Ingvar
    Blekinge Institute of Technology.
    Chapter 15 – The VISIR Open Lab Platform2011In: InternetAccessible Remote Laboratories: Scalable E-learning Tools for Engineering and Science Disciplines / [ed] M. E. Auer, V. J. Harward and A. K. M. Azad, IGI Global, 2011, p. 294-317Chapter in book (Refereed)
    Abstract [en]

    The VISIR Open Lab Platform designed at the Department of Electrical Engineering (AET), the Blekinge Institute of Technology (BTH), Sweden, is a platform for opening instructional laboratories for remote access 24/7 with preserved context. VISIR is an acronym for Virtual Instrument Systems in Reality. In VISIR laboratories, students perform physical experiments and laboratory work remotely. A unique interface gives them the feeling of “being there.” The platform software is published under a GPL license, and other universities, schools, et cetera, are invited use it to open their laboratories and to participate in further research and development. Apart from BTH, five universities in Europe have set up VISIR online laboratories for electrical experiments and the Indian Institute of Technology Madras in India will set up one soon. A VISIR community has been established. Common projects are initiated, and the sharing of learning material is being discussed. This chapter is a general introduction to VISIR and its possibilities.

  • 14.
    Gustavsson, Ingvar
    et al.
    Blekinge Institute of Technology.
    Nilsson, Kristian
    Blekinge Institute of Technology.
    Zackrisson, Johan
    Blekinge Institute of Technology.
    Garcia-Zubia, Javier
    University of Deusto, Spain.
    Hernandez-Jayo, Unai
    University of Deusto, Spain.
    Nafalski, Andrew
    University of South Australia, Australia.
    Nedic, Zorica
    University of South Australia, Australia.
    Göl, Özdemir
    University of South Australia, Australia.
    Machotka, Jan
    University of South Australia, Australia.
    Pettersson, Mats
    Blekinge Institute of Technology.
    Lagö, Thomas
    Acticut International AB, Falkenburg.
    Håkansson, Lars
    Blekinge Institute of Technology.
    On objectives of instructional laboratories, individual assessment, and use of collaborative remote laboratories2009In: IEEE Transactions on Learning Technologies, ISSN 1939-1382, E-ISSN 1939-1382, Vol. 2, no 4, p. 263-274Article in journal (Refereed)
    Abstract [en]

    Three key issues should be addressed to enable universities to deliver engineers who have a solid documented laboratory experience enabling them to design goods and services complying with the requirements of a sustainable society. First, introduce learning objectives of engineering instructional laboratories in courses including laboratory components. Second, implement individual student assessment. Third, introduce free access to online experimental resources as a supplement to the equipment in traditional laboratories. Blekinge Institute of Technology (BTH) in Sweden and the University of South Australia (UniSA) have created online laboratory workbenches for electrical experiments that mimic traditional ones by combining virtual and physical reality. Online workbenches not only supplement traditional ones, but they can also be used for low-cost individual assessment. BTH has started a project disseminating the BTH workbench concept, The Virtual Instrument Systems in Reality (VISIR) Open Laboratory Platform, and invites other universities to set up replicas and participate in further development and standardization. Further, online workbenches offer additional learning possibilities. UniSA has started a project where students located in different countries can perform experiments together as a way to enhance the participants' intercultural competence. This paper discusses online laboratory workbenches and their role in an engineering education appropriate for a sustainable society.

  • 15.
    Gustavsson, Ingvar
    et al.
    Blekinge Institute of Technology.
    Zackrisson, Johan
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Chapter 11 – A new Concept for Distributed Laboratories Based on Open Source Technology2007In: Advances on remote laboratories and e-learning experiences / [ed] L. Gomes and J. Garcia-Zubia, Deusto Publicaciones , 2007, p. 247-267Chapter in book (Refereed)
  • 16.
    Håkansson, Lars
    IIAV, United States.
    The Fourier Transform in Sound and Vibration2015In: International Journal of Acoustics and Vibration, ISSN 1027-5851, E-ISSN 2415-1408, Vol. 20, no 4, p. 190-190Article in journal (Refereed)
  • 17.
    Håkansson, Lars
    et al.
    Blekinge Institute of Technology.
    Johansson, Sven
    Blekinge Institute of Technology.
    Claesson, Ingvar
    Blekinge Institute of Technology.
    Chapter 81– Machine Tool Noise, Vibration and Chatter Prediction and Control2007In: Handbook of Noise and Vibration Control / [ed] Malcolm J. Crocker, John Wiley & Sons, 2007Chapter in book (Refereed)
  • 18. Håkansson, Lars
    et al.
    Johansson, Sven
    Dahl, Mattias
    Sjösten, Per
    Claesson, Ingvar
    Chapter 12 – Noise Canceling Headsets for Speech Communication2002In: Noise Reduction in Speech Applications / [ed] Gillian M. Davis, CRC Press, 2002, p. 305-328Chapter in book (Refereed)
  • 19. Håkansson, Lars
    et al.
    Khan, Imran
    Sharafi, Amir
    Zackrisson, Johan
    Development and Implementation of an Advanced Remotely Controlled Vibration Laboratory2014In: 2014 11th International Conference on Remote Engineering and Virtual Instrumentation (REV), IEEE, 2014, p. 382-385Conference paper (Refereed)
    Abstract [en]

    Currently an advanced remotely controlled vibration laboratory is developed and implemented at Blekinge Institute of Technology, Karlskrona, Sweden. The new developments in the laboratory setup will provide users to carry out vibration measurements on a cantilever beam system with remotely adjustable dynamic properties and to estimate dynamic characteristics of it. The dynamic properties of the cantilever beam are remotely modified by attaching structural parts such as a block of mass, a spring mass system and a non-linear spring. In the development of this remote-lab, a number of different approaches were adopted for the production of well-defined experiments. Also, the new prototype laboratory is designed based on finite elements modeling (FEM) and LABVIEW. The test object, attachment mechanism for sub structures, relevant experiments, and proper interface for managing the lab via Internet and many other things have been considered.

  • 20. Håkansson, Lars
    et al.
    Olsson, Sven
    Claesson, Ingvar
    Anordning för styrning av vibrationer i en maskin förskärande bearbetning2004Patent (Other (popular science, discussion, etc.))
  • 21.
    Johansson, Ebba
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Dahlman, Rikard
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Andersson, Magnus
    Volvo CE, Sweden.
    Vibration induced fatigue life estimation based on non-stationary stochastic processes segmented to piesewise stationary segments2019In: Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019, Montreal, Canada: Canadian Acoustical Association , 2019Conference paper (Other academic)
    Abstract [en]

    At excavations of quarries, construction sites or in mining, etc. articulated haulers are commonly used for the transportation of material. Thus, articulated haulers are exposed to a diversity of different worksites that all will load them differently. With a continuously growing market and added exhaust emission regulations, the machines need to be continuously optimized to meet durability and weight (fuel efficiency) requirements. In the structural design of any given component in an articulated hauler, the assumed loads used will reflect on its design. However, it is rarely the case that the loads used in the design procedure strictly represents the dynamic loads a hauler will be subjected to. As a result, the machines are generally oversized. To address the issue of oversized components, a statistical approach for the estimation of their fatigue life may be utilized. With the aid of power spectral density estimates of a components dynamic loads in combination with a finite element model of the component its vibration response in terms of power spectral densities may be estimated. Based on the vibration response spectra the component's fatigue life may be estimated assuming that the components dynamic loads may be considered as weakly stationary stochastic processes. To investigate if the dynamic loads used for fatigue life estimation may be considered as weakly stationary stochastic processes; stationarity tests have been carried out as well as estimates of the kurtosis and the mean square value as a function of time have been produced. The results indicate that the dynamic loads may not be considered as weakly stationary stochastic processes. Furthermore, by segmenting the dynamic load time series into segments that can be considered as weakly stationary the estimated fatigue life seems to decrease slightly if compared to the case when assuming that the dynamic loads are weakly stationary.

  • 22. Johansson, Sven
    et al.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Claesson, Ingvar
    Chapter 100 – Aircraft Cabin Noise and Vibration Predictionand Active Control2007In: Handbook of noise and vibration control / [ed] Malcolm J. Crocker, John Wiley & Sons, 2007Chapter in book (Refereed)
  • 23.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Campos, Jaime
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    A remote laboratory for Maintenance 4.0 training and education2020In: 4th IFAC Workshop on Advanced Maintenance Engineering, Services and Technologies - AMEST 2020 / [ed] Ajith Parlikad, Christos Emmanouilidis, Benoit Iung, Marco Macchi, Elsevier, 2020, Vol. 53, p. 101-106Conference paper (Refereed)
    Abstract [en]

    The paper suggests a remote condition monitoring and maintenance laboratory environment based on theIndustry 4.0 concept. The architecture provides a remote connection with distance students and a test rig, which permitsthem to be able to perform condition monitoring, diagnostic, prognostics, etc. on the equipment. The ICT architecturefollows standards, such as the MIMOSA CRIS and the OSA-CBM. The remote laboratory environment supportslifelong learning as well as relevant training for the modern engineer and highlights the specific requirements of amaintenance engineer. As an example, the objectives and expected learning outcomes for a course in Maintenance 4.0fundamentals are displayed. The expected results are, among others, increased maintenance competences in theindustry, and the improvements of the different maintenance services following a predictive, condition-basedmaintenance strategy.

    Download full text (pdf)
    fulltext
  • 24.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Campos, Jaime
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    An ICT System for Gravel Road Maintenance: Information and Functionality Requirements2022In: International Congress and Workshop on Industrial AI 2021 / [ed] Ramin Karim, Alireza Ahmadi, Iman Soleimanmeigouni, Ravdeep Kour, Raj Rao, Springer, 2022, p. 53-64Conference paper (Refereed)
    Abstract [en]

    The gravel road network is an important function for rural residents and entrepreneurs. Traditional maintenance of gravel roads is well-functioning but provides a relatively high maintenance cost per unit length of the road, and every maintenance action as well as extraction and transport of new gravel contributes to increased climate impact and resource depletion. Today, maintenance planning is carried out periodically based on the maintenance history, which also is reflected in the economic models and procurement methods. Current maintenance plans may be enhanced and will not be a reliable basis in the future, e.g. due to climate change. Instead, real needs and conditions must be given greater consideration. Today, appropriate maintenance management systems are lacking, e.g. in order to be able to evaluate maintenance deficiencies, prioritize objects and choose the appropriate maintenance action. Moreover, the knowledge available at specific stakeholders is not shared with other actors. In this paper, an Information and Communication Technology (ICT) system for gravel road maintenance is proposed in the form of a cloud-based system covering the information needs of stakeholders in the gravel road maintenance ecosystem. Requirement specifications are given for the sub-systems intended for the maintenance executioner and the maintenance planner. The specifications are based on workshops and interviews conducted with stakeholders, where requirements were acquired e.g. in the form of User stories.

  • 25.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Campos, Jaime
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Condition Monitoring of Gravel Roads: Current Methods and Future Directions2020In: Advances in Asset Management and Condition Monitoring. Smart Innovation, Systems and Technologies: COMADEM 2019 / [ed] Ball A., Gelman L., Rao B., Springer, 2020, p. 451-461Chapter in book (Refereed)
    Abstract [en]

    High quality information is essential for the efficient decision making. Road condition is, together with traffic frequency, commonly used as input for classifying road status. Road condition is also a major input for the maintenance executor (vehicle operator) when deciding on maintenance actions, such as amount of gravel to replenish. With better condition related information, the maintenance execution as well as maintenance planning could be greatly improved. The current deficiencies in gravel road condition monitoring methods and technologies are described in this paper, and an approach for objective measurement of gravel road condition is proposed, including new measurement techniques and systems as well as information processing for decision making. This is realized by utilizing research findings from the area of signal processing, maintenance engineering, and information systems engineering in the specific context of gravel road monitoring, thus utilizing available technologies and methods as well as physics.

  • 26.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Campos, Jaime
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Current practices and new approaches within condition monitoring of gravel roads2020In: International Journal of COMADEM, ISSN 1363-7681, Vol. 23, no 4, p. 3-8Article in journal (Refereed)
    Abstract [en]

    High quality information is essential for the efficient decision making. Road condition is, together with traffic frequency, commonly used as input forclassifying road status. Road condition is also a major input for the maintenance executor (vehicle operator) when deciding on maintenance actions, such asamount of gravel to replenish. With better condition related information, the maintenance execution as well as maintenance planning could be greatlyimproved. The current deficiencies in gravel road condition monitoring methods and technologies are described in this paper, and an approach for objectivemeasurement of gravel road condition is proposed, including new measurement techniques and systems as well as information processing for decision making.This is realized by utilizing research findings from the area of signal processing, maintenance engineering, and information systems engineering in the specificcontext of gravel road monitoring, thus utilizing available technologies and methods as well as physics.

  • 27.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering. Chalmers University of Technology, Sweden.
    Campos, Jaime
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    The development of a cloud-based information system for gravel road maintenance2022In: International Journal of COMADEM, ISSN 1363-7681, Vol. 25, no 2, p. 31-38Article in journal (Refereed)
    Abstract [en]

    The gravel road network is an essential function for rural residents and entrepreneurs. Traditional maintenance of gravel roads is well-functioning but provides a relatively high maintenance cost per unit length of the road. In addition, every maintenance action and extraction and transport of new gravel contribute to increased climate impact and resource depletion. Today, maintenance planning is carried out periodically based on the maintenance history, which also is reflected in the economic models and procurement methods. Current maintenance plans may be enhanced and will not be a reliable basis in the future, for instance due to climate change. Instead, real needs and conditions must be given greater consideration. Today, appropriate maintenance management systems are lacking, e.g., to be able to evaluate maintenance deficiencies, prioritize objects and choose the appropriate maintenance action. Moreover, the knowledge available at specific stakeholders is not shared with other actors. In this paper, an Information and Communication Technology (ICT) system for gravel road maintenance is proposed in the form of a cloud-based system covering the information needs of stakeholders in the gravel road maintenance ecosystem. Requirement specifications are given for the subsystems intended for the maintenance executioner and the maintenance planner. The specifications are based on workshops and interviews conducted with stakeholders, where requirements were acquired using techniques such as User stories, Use case scenarios, and mock-up prototypes. System examples corresponding to the requirements specifications are also given.

  • 28.
    Khan, Imran
    et al.
    Blekinge Institute of Technology.
    Gertsovich, Irina
    Blekinge Institute of Technology.
    Claesson, Ingvar
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Johansson, Per-Erik
    Blekinge County Hospital.
    Wirenstedt, Maria
    Blekinge County Hospital.
    Bona, Oscar
    Blekinge County Hospital.
    Petersson, Stefan
    GE Healthcare, UK, MR Division, Hertfordshire, United Kingdom .
    MRI scanner vibration path analysis2013In: 20th International Congress on Sound and Vibration 2013 (ICSV 20), Curran Associates, Inc., 2013, Vol. 4, p. 3560-3567Conference paper (Other academic)
    Abstract [en]

    Magnetic Resonance Imaging (MRI) scanner is one of the most important tools in clinical diagnostics. MRI scanners are associated by strong vibration which results in unpleasant and disturbing acoustic noise. The primary source of this vibration is the Lorentz force produced by fast switching of the currents inside the gradient coils of MRI scanners under a strong static magnetic field. During an MR-imaging scan the switching is controlled in order to spatially code the hydrogen nuclei that will generate the signal, which is reconstructed into anatomical images. Faster switching of the currents allows for shorter scan times and/or higher image resolutions. Consequently, the clinical quality has motivated the drive for shorter switching time and higher currents. This development, however, has also caused an undesired increase of MRI vibrations. The overall vibration phenomenon of an installed fully functional MRI scanner system becomes unique because of the installed location and ambiance. This vibration can potentially degrade the image quality and hence the diagnosis. Apart from the vibration produced, the associated annoying acoustic noise may not only affect the patients under examination and the clinical staff, but may also be transmitted to other parts of the building and causing discomfort for the personnel working there. In order to devise an effective isolation plan or improve an existing one both for vibration and acoustic noise it is important to study the noise and vibration transfer paths. This paper concerns an investigation of vibration transfer paths for vibration excited by an installed functional MRI scanner at a medical facility. The vibration transfer paths have been investigated experimentally. The obtained results are presented and discussed.

  • 29.
    Khan, Imran
    et al.
    Blekinge Institute of Technology.
    Moazzam, Muhammad
    Rabbani, Shoaib
    Blekinge Institute of Technology.
    Johansson, Sven
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Performance  Evaluation of Control Algorithms Implemented on a Remotely Controlled Active Noise Control Laboratory2013In: 20th International Congress on Sound and Vibration 2013 (ICSV 20), Curran Associates, Inc., 2013Conference paper (Other academic)
    Abstract [en]

    The remotely controlled laboratory setup for Active Noise Control (ANC) developed by Blekin-ge Institute of Technology, Sweden provides an efficient learning platform for the students to implement and learn ANC algorithms with real world physical system, hardware and signals. The initial laboratory prototype based on a Digital Signal Processor (DSP) TMS320C6713 from Texas Instruments (TI) was successfully tested with Filtered-x Least Mean Square (F-XLMS) algorithm applied to control noise in a ventilation duct. The resources of the DSP platform used in the remote laboratory setup enable testing and investigating substantially more challenging and computationally demanding algorithms. In this paper, we expand the horizon of the laboratory setup by testing more advanced and complicated single channel feed forward ANC algorithms. Filtered-x versions of algorithms such as the normalized least mean square (N-LMS), leaky least mean square (L-LMS), Filtered-U recursive least mean square (FURLMS) and recursive least square (RLS) algorithm etc. have been implemented utilizing the remote web based client provided in the remote laboratory. A comprehensive performance comparison of the aforementioned algorithms for the remote laboratory setup is presented to demonstrate the viability of the remote laboratory.

  • 30.
    Khan, Imran
    et al.
    Blekinge Institute of Technology.
    Muthusamy, Dinesh
    Blekinge Institute of Technology.
    Ahmad, Waqas
    Blekinge Institute of Technology.
    Gustavsson, Ingvar
    Blekinge Institute of Technology.
    Zackrisson, Johan
    Blekinge Institute of Technology.
    Nilsson, Kristian
    Blekinge Institute of Technology.
    Johansson, Sven
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Remotely Controlled Active Noise Contol Laboratiories2012In: The Nineteenth International Congress on Sound and Vivration, Curran Associates, Inc., 2012Conference paper (Other academic)
    Abstract [en]

    Remotely controlled laboratories in educational institutions are gaining popularity at an exponential rate due to the multidimensional benefits they provide. The Virtual Instrument Systems in Reality (VISIR) project by Blekinge Institute of Technology (BTH) Sweden has successfully implemented remotely controlled laboratories, with remotely controlled real instruments and experimental setups. Currently these laboratories provide students the opportunity to conduct experiments in the field of electronics, antenna theory and mechanical vibration measurements. In this paper a prototype system of a remotely controlled laboratory for active noise control (ANC) is introduced. The proposed lab will focus on addressing the problem of a ventilation duct noise. The laboratory is informative and to a great extent introduces a student to the general steps in ANC when it is suggested as a plausible solution for a noise problem. The student can perform an investigation concerning feasibility of active control, design, configuration and implementation of an active control system. The laboratory is based on a modern and relevant DSP platform with the corresponding software development environment controlled remotely. In addition, it may be utilized remotely both for lab assignments in acoustics courses and digital signal processing courses.

  • 31.
    Khan, Imran
    et al.
    Blekinge Institute of Technology.
    Muthusamy, Dinesh
    Blekinge Institute of Technology.
    Ahmad, Waqas
    Blekinge Institute of Technology.
    Nilsson, Kristian
    Blekinge Institute of Technology.
    Zackrisson, Johan
    Blekinge Institute of Technology.
    Gustavsson, Ingvar
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Remotely Controlled Laboratory Setup for Active Noise Control and Acoustic Experiments2012In: 2012 9th International Conference on Remote Engineering and Virtual, IEEE, 2012Conference paper (Refereed)
    Abstract [en]

    This paper presents a remotely controlled educational experiments setup for Active Noise Control (ANC) and acoustic experiments. The experiments setup is based on the Virtual Instruments Systems in Reality (VISIR) open source platform, National Instruments LabVIEW software and a Digital Signal Processor TMS320C6713 from Texas Instruments. The software development and equipment are controlled remotely form a client PC using a standard web browser. The proposed laboratory setup focuses on ANC experiments applied to noise in a ventilation duct. The laboratory setup will enable students to test and investigate properties and behaviour of adaptive algorithms in reality as compared to more confined simulations usually carried out in Matlab etc. The general steps in ANC, such as the feasibility of active control, designing, testing and debugging ANC algorithms, configuration and implementation of an active control system, are all covered. In addition students will be able to study the effect of analog to digital converters (ADC), anti-aliasing filters, digital to analog converters (DAC) and reconstruction filters using digital signal processing in reality, etc. The laboratory setup is suitable for a wide range of courses such as sound related experiments in upper secondary school physics, digital signal processing, adaptive signal processing, and acoustics at university level.

  • 32.
    Khan, Imran
    et al.
    Blekinge Institute of Technology.
    Muthusamy, Dinesh
    Blekinge Institute of Technology.
    Ahmad, Waqas
    Sällberg, Benny
    Blekinge Institute of Technology.
    Nilsson, Kristian
    Blekinge Institute of Technology.
    Zackrisson, Johan
    Blekinge Institute of Technology.
    Gustavsson, Ingvar
    Blekinge Institute of Technology.
    Håkansson, Lars
    Performing Active Noise Control and Acoustic Experiments Remotely2012In: International Journal of Online Engineering, ISSN 1868-1646, E-ISSN 1861-2121, Vol. 8, no Special Issue, p. 65-74Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel and advanced remotely controlled laboratory for conducting Active Noise Control (ANC), acoustic and Digital Signal Processing (DSP) experiments. The laboratory facility, recently developed by Blekinge Institute of Technology (BTH) Sweden, supports remote learning through internet covering beginners level such as simple experimental measurements to advanced users and even researchers such as algorithm development and their performance evaluation on DSP. The required software development for ANC algorithms and equipment control are carried out anywhere in the world remotely from an internet-connected client PC using a standard web browser. The paper describes in detail how ANC, acoustic and DSP experiments can be performed remotely The necessary steps involved in an ANC experiment such as validity of ANC, forward path estimation and active control applied to a broad band random noise [0-200Hz] in a ventilation duct will be described in detail. The limitations and challenges such as the forward path and nonlinearities pertinent to the remote laboratory setup will be described for the guidance of the user. Based on the acoustic properties of the ventilation duct some of the possible acoustic experiments such as mode shapes analysis and standing waves analysis etc. will also be discussed in the paper.

  • 33.
    Khan, Imran
    et al.
    Blekinge Institute of Technology.
    Nygren, Åse
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Challenges in Fulfilling the Intended Learning Outcomes of Remote of Laboratories: A Case Study of Active Noise Control and Acoustic Remote Laboratory2015In: 22nd International Congress on Sound and Vibration 2015 (ICSV 22), Curran Associates, Inc., 2015Conference paper (Other academic)
  • 34.
    Khan, Imran
    et al.
    Blekinge Institute of Technology.
    Żmuda, Maciej
    Blekinge Institute of Technology.
    Konopka, Piotr
    Blekinge Institute of Technology.
    Gustavsson, Ingvar
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Enhancement of Remotely Controlled Laboratory for Active Noise Control and Acoustic Experiments2014In: 2014 11th International Conference on Remote Engineering and Virtual Instrumentation (REV), IEEE, 2014, p. 285-290Conference paper (Refereed)
    Abstract [en]

    The latest important developments in the remotely controlled Active Noise Control (ANC) and Acoustics laboratory at Blekinge Institute of Technology (BTH), Sweden, are introduced. The remotely controlled laboratory is based on the Virtual Instruments Systems in Reality (VISIR) concept, and concerns multi-channel measurement and control of the sound field in a heating ventilation and air conditioning (HVAC) duct. Originally the ventilation duct was equipped with a fixed number of microphones at fixed spatial locations in the duct. A microphone positioning system has been designed and implemented. It enables control of the spatial positions of a number of microphones inside the HVAC duct using a suitable web interface for controlling stepper motors via a National Instruments (NI) PXI system. With the new developments, the spatial number of selectable positions for the microphones have been extended substantially. The new microphone positioning control system is presented and to enhance the user interaction with the laboratory equipment, an audio and visual system is also proposed.

  • 35.
    Khan, Imran
    et al.
    Blekinge Institute of Technology.
    Żmuda, Maciej
    Konopka, Piotr
    Håkansson, Lars
    Blekinge Institute of Technology.
    Remote Control of Active Noise Control and Acoustics Experiment Setup via the Internet2014In: 21st International Congress on Sound and Vibration 2014 (ICSV 21) / [ed] Crocker, M.J., Curran Associates, Inc., 2014Conference paper (Other academic)
  • 36.
    Kodakadath Premachandran, Rammohan
    et al.
    Atlas Copco, SWE.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Comparison of Spectral Properties of the Vibration Signal and Line Pressure Signal of DTH Drill2016In: 23rd International Congress on Sound and Vibration 2016 (ICSV 23): From Ancient to Modern Acoustics, Publisher: Curran Associates, Inc., Curran Associates, Inc., 2016Conference paper (Other academic)
    Abstract [en]

    Quantifying and Monitoring of drilling performance are becoming exceedingly important in the case of Down the Hole drilling. Various economic, environmental and safety constraints are driving the drilling process to become more efficient. To make a robust system that would enable the performance/condition monitoring of the drilling, we must understand how different properties like different line pressure etc. respond to various drilling conditions and what information can they provide regarding the Drilling Performance. A comparison of different properties like spectral properties, of the vibration signals and Pressure signals under known conditions would enable better understanding of the drilling system and the physics behind the process. A comparison is made between the Spectral properties of the vibrational signals obtained from remote locations on the drill rig and pressure signals that provide the feed and holdback forces to the drill string and a correlation between their characteristics and patterns under good and bad drilling conditions have been made. A simplified model of the system is simulated and results are compared with the patterns obtained from analyzing the Vibration signals.

  • 37.
    Kodakadath Premachandran, Rammohan
    et al.
    Atlas Copco.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Signal Analysis for Performance Monitoring of Drilling with Down the Hole (DTH) Rock Drills2015In: 22nd International Congress on Sound and Vibration 2015 (ICSV 22), Curran Associates, Inc., 2015Conference paper (Other academic)
  • 38.
    Kodakadath Premachandran, Rammohan
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Linderholt, Andreas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Methodology for 3D simulation and analisys of a combination of axial impact and rotation of a DTH drilling system2023In: 29th International Congress of Sound and Vibration, 2023Conference paper (Other academic)
    Abstract [en]

    There is an increasing need for an effective monitoring strategy for the performance and condition of Down The Hole drilling. To achieve that, it is important to gain knowledge in the physics involved in Down The Hole drilling processes.A logical way to gain such understanding is to develop simulation models that are capable to represent the process. That requires physical understanding and thus, it is an iterative process. To capture the physics, it is essential to couple the axial impact, and the subsequent axial motion, with the rotation of the drill. The indentation into the rock due to impact and the subsequent resistance against rotation will couple the rotation to the axial motion and vice versa. The scenario is complicated due to the non-linear nature in the contacts and the varying stiffness of the rock.This paper presents a methodology that can be used to couple the axial and rotational motions of the DTH drills and explores the pros and cons of such a 3D simulation model.Keywords: DTH, 3D simulation, Condition monitoring

    Download full text (pdf)
    fulltext
  • 39.
    Kodakadath Premachandran, Rammohan
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Linderholt, Andreas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Modelling of DTH drilling cycle combining both axial motion and rotation2022In: ICSV28, 2022Conference paper (Other academic)
    Abstract [en]

    Reliable simulations of the DTH drilling cycle are important in understanding the physics related todrilling, which in turn enables development of robust performance and condition monitoring methodologies. The DTH models available today model different aspects of the system like impact, hydraulics etc. separately. There are models available that incorporates hydraulics/pneumatics with onedimensional structural dynamics of the system. A common drawback of such models is that the effectof rotation is neglected. In reality rotation is an integral part of the DTH system and is interconnectedwith other parameters of drilling. This paper focuses on a simple model that combines rotation of thedrill string with the impact and hydraulic mechanics. The aim is to build upon this basic model tofacilitate the development of a more robust and accurate model that represents the condition andperformance monitoring problem.

  • 40.
    Kodakadath Premachandran, Rammohan
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Linderholt, Andreas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Simulation models of down the hole drilling: A step towards automized drilling based on monitoring2021In: Proceedings of the 27th International Congress on Sound and Vibration, 2021Conference paper (Refereed)
    Abstract [en]

    Automation of the drilling process is a widely spread goal in the rock excavator industry. An intermediate step can be to assist a manual drilling process by informing the operator of the quality of the drilling. To reach the goals, it is thus imperative to have a high performance monitoring system based on physics involved in the drilling process. A necessity to develop such an information system, is insight into the physics involved in the drilling process. This can be gained by using combinations of simulations, lab tests and in-situ tests.

    Here, a 1D model representing Down The Hole (DTH) drilling is used. Such a model can be further developed to simulate good and bad performance of drilling. The resulting vibration responses, hydraulic pressure responses, etc. of the system can be analyzed with the purpose to identify possible sources of informative data which can be measured and recorded during a real world rock drilling operation.

    Here, a simplified 3D model of the DTH drilling system involving the bit, hammer and the drill string is also made and used together with boundary conditions constituting a simplified model of the rock. The aim here is to find a computationally efficient 3D modeling methodology to simulate the drilling for various conditions, due to various drilling parameter settings. The aim is to develop a 3D model that can be refined further and can be used extensively to understand the DTH drilling process in order to facilitate performance monitoring and in the end automized DTH drilling.

    Download full text (pdf)
    fulltext
  • 41.
    Kodakadath Premachandran, Rammohan
    et al.
    Atlas Copco Rock Drills AB, Sweden.
    Linderholt, Andreas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Gothberg, Mattias
    Atlas Copco Rock Drills AB, Sweden.
    An initial investigation of the correlation between a number of drilling related quantities measured during down the hole drilling2017In: Proceedings of the 24th International Congress on Sound and Vibration, Curran Associates, Inc., 2017Conference paper (Other academic)
    Abstract [en]

    Optimizing the performance for down the hole (DTH) drills is becoming increasingly important. This is due to that the industry is becoming highly competitive and therefore there is an ever-increasing demand for improving the efficiency of the drilling process. To do this, it is important to have a robust monitoring system in place that should be based on in-depth knowledge of the underlying physics of the drilling system and process. Such a system will assist drillers in improving the perfor-mance e.g. by providing recommendations concerning the settings of the drilling. To understand the performance of the system, it is very important to understand the information that can be extracted from different drilling related quantities. In this work, information obtained from the pressure signals from the feed/holdback line, impact pressure line and rotation line together with vibration signals measured with the aid of accelerometers mounted at specific locations on the drill rig are discussed. For instance, spectral properties of these quantities for good and bad drilling cases are investigated. The results indicate correlations, to some extent, between the spectral properties and the quality of the drilling.

    Download full text (pdf)
    fulltext
  • 42.
    Kodakadath Premachandran, Rammohan
    et al.
    Atlas Copco Rock Drills AB, Sweden.
    Linderholt, Andreas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Gothberg, Mattias
    Atlas Copco Rock Drills AB, Sweden.
    Numerical 1D and 3D models representing a DTH drilling system: A comparison of accuracy and computational speed2018In: 25th International Congress on Sound and Vibration 2018 (ICSV 25): Hiroshima Calling. Proceedings of a meeting held 8-12 July 2018, Hiroshima, Japan, Auburn, AL: International Institute of Acoustics & Vibration , 2018, Vol. 1, p. 394-401Conference paper (Refereed)
    Abstract [en]

    The drilling industry is steadily moving towards automation. To have a better control over the drilling operation and to optimize the drilling performance, it is necessary to have a good understanding of the physics involved in the process. A good simulation model of the drilling process/system would be of great value in assisting this and in enabling the development of strategies to optimize it. A representative simulation model can provide insights into various phenomena that appear during drilling for different drilling conditions. Such a model is also likely to be of assistance in preparing various measurements. Issues such as choosing the type of sensors, their positions and which quantities to measure are supported by a model. A well calibrated model in combination with information extracted from measured data are hence likely to assist in selecting control strategies for optimized drilling performance. In this paper we present a MATLAB based 1D simulation model of a Down The Hole (DTH) drill and compare it with an existing 1D model in terms of computational speed and accuracy. The emphasis is to make a 3D model of a DTH system that is computationally efficient and accurate.

  • 43.
    Källström, Elisabeth
    et al.
    Luleå University of Technology ; Volvo Construction Equipment.
    Lindström, John
    Luleå University of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Karlberg, Magnus
    Luleå University of Technology.
    Bellgran, David
    Volvo Construction Equipment.
    Frenne, Nicklas
    Volvo Construction Equipment.
    Renderstedt, Reza
    Volvo Construction Equipment.
    Lundin, Joakim
    Volvo Construction Equipment.
    Larsson, Jonas
    Volvo Construction Equipment.
    Analysis of Automatic Transmission Vibration for Clutch Slippage Detection2015In: 22nd International Congress on Sound and Vibration 2015 (ICSV 22),, Curran Associates, Inc., 2015Conference paper (Refereed)
    Abstract [en]

    Heavy duty construction equipment is generally equipped with automatic transmission enablingto change gear ratio automatically. The clutches in an automatic transmission transfer torquefrom the engine to the gearbox and clutch failures may result in costly downtime of constructionequipment. To prevent costly downtime of construction equipment, condition monitoring in com-bination with condition based maintenance may be utilized. Different sensor data are collectedon a machine that enables condition monitoring. Vibration have been measured on an automatictransmission in a construction equipment machine during controlled driving sessions, with andwithout clutch slippage, on a test track. An initial investigation of the vibration measured on theautomatic transmission have been carried out with the purpose to find out if the vibration maycontain reliable information related to clutch slippage considered to be abnormal. Initial signalanalysis of the data have been carried out using Spectrogram and Spectral Kurtosis methods. Theresults indicate that information related to abnormal clutch slippage may be extracted from vibra-tion measured on an automatic transmission in a construction equipment machine.

  • 44.
    Källström, Elisabeth
    et al.
    Luleå University of Technology, Sweden;Volvo Construction Equipment, Sweden.
    Lindström, John
    Luleå University of Technology, Sweden.
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Karlberg, Magnus
    Luleå University of Technology, Sweden.
    Lin, Jing
    Luleå University of Technology, Sweden.
    Vibration-based Condition Monitoring of Heavy Duty Machine Driveline Parts: Torque Converter, Gearbox, Axles and Bearings2019In: International Journal of Prognostics and Health Management, E-ISSN 2153-2648, Vol. 10, no 2, p. 1-12, article id 014Article in journal (Refereed)
    Abstract [en]

    As more features are added to the heavy duty construction equipment, its complexity increases and early fault detection of certain components becomes more challenging due to too many fault codes generated when a failure occurs. Hence, there is a need to complement the present onboard diagnostics method with a more reliable diagnostics method for adequate condition monitoring of the heavy duty construction equipment in order to improve uptime.Major components of the driveline (such as the gearbox, torque converter, bearings and axles) are components necessary to monitor. A failure among any of these major components of the driveline may result in the machine standing still until a repair is scheduled.

    In this paper, vibration based condition monitoring methods are presented with the purpose to provide a diagnostic framework possible to implement onboard for monitoring of critical driveline parts in order to reduce service cost and improve uptime.For the development of this diagnostic framework, sensor data from the gearbox, torque converter, bearings and axles are considered. Further, the feature extraction of the data collected has been carried out using adequate signal processing methods, which includes: Adaptive Line Enhancer and Order Power Spectrum respectively. In addition, Bayesian learning was utilized for adaptive learning of the extracted features for deviation detection. Bayesian learning is a powerful prediction method as it combines the prior information with knowledge measured to make updates. The results indicate that the vibration properties of the gearbox, torque converter, bearings and axle are relevant for early fault detection of the driveline. Furthermore, vibration provides information about the internal features of these components for detecting deviations from normal behavior.

    In this way, the developed methods may be implemented onboard for the continuous monitoring of these critical driveline parts of the heavy duty construction equipment. Thus, if their health starts to degrade a service and/or repair may be scheduled well in advance of a potential failure and in that way the downtime of a machine may be reduced and costly replacements and repairs avoided.

  • 45.
    Källström, Elisabeth
    et al.
    Luleå University of Technology.
    Lindström, John
    Luleå University of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Karlberg, Magnus
    Luleå University of Technology.
    Renderstedt, Reza
    Volvo Construction Equipment.
    Larsson, Jonas
    Volvo Construction Equipment.
    Identification of Vibration Properties of Heavy Duty Machine Driveline Parts as a Base for Adequate Condition Monitoring: Axle2016In: 23rd International Congress on Sound and Vibration 2016 (ICSV 23): From Ancient to Modern Acoustics, Curran Associates, Inc., 2016Conference paper (Refereed)
    Abstract [en]

    With increasing complexity in the heavy duty construction equipment, early fault detection ofcertain components in the machine becomes more and more challenging due to too many faultcodes generated when a failure occurs. The axle is one such component. The axle transfers driv-ing torque from the transmission to the wheels and axle failure may result in costly downtime ofconstruction equipment. To reduce service cost and to improve uptime, adequate condition moni-toring based on sensor data from the axle is considered by for instance measuring vibrations on theaxle. Further, the analysis of the data collected has been has been carried out using adequate sig-nal processing methods. The results indicate that the vibration properties of the axle are relevantfor early fault detection of the axle. Thus, the health of the axle may be continuously monitoredon-board using the vibration information and if the axle health starts to degrade a service and/orrepair may be scheduled well in advance of a potential axle failure and in that way the downtimeof a machine may be reduced and costly replacements and repairs avoided.

  • 46. Källström, Elisabeth
    et al.
    Lindström, John
    Håkansson, Lars
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Karlberg, Magnus
    Öberg, Olof
    Identification of Vibration Properties of Wheel Loader Driveline Parts as a base for Adequate Condition Monitoring: Bearings2017In: 24th International Congress on Sound and Vibration 2017 (ICSV 24) / [ed] Malcolm Crocker, Curran Associates, Inc., 2017, Vol. 1, p. 312-319Conference paper (Refereed)
  • 47.
    Källström, Elisabeth
    et al.
    Luleå University of Technology.
    Lindström, John
    Luleå University of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Karlberg, Magnus
    Luleå University of Technology.
    Öberg, Olof
    Volvo Construction Equipment.
    Renderstedt, Reza
    Volvo Construction Equipment.
    Larsson, Jonas
    Volvo Construction Equipment.
    Identification of Vibration Properties of Heavy Duty Machine Driveline Parts as a Base for Adequate Condition Monitoring: Torque Converter2016In: 23rd International Congress on Sound and Vibration 2016 (ICSV 23): From Ancient to Modern Acoustics, Publisher: Curran Associates, Inc., Curran Associates, Inc., 2016Conference paper (Refereed)
    Abstract [en]

    Improving uptime is paramount in the heavy duty construction equipment business. Failure ofcritical components in the heavy duty machine may lead to unnecessary stops and expensivedowntime. The torque converter, a complex component of the driveline, transmits and multipliestorque from the engine to the gearbox, and its failure may not only lead to the machine standingstill but may also lead to damage of other parts of the automatic transmission.For adequate condition monitoring of the torque converter, different sensor data are measuredon a construction equipment machine during controlled driving sessions. Vibration has beenmeasured on the torque converter. An initial investigation of the vibration measured on the torqueconverter has been carried out to identify its vibration properties in order to enable its healthmonitoring to prevent failure. Initial signal analysis of the data have been carried out using OrderPower Spectrum and Order Modulation Spectrum methods. The results indicate that the torqueconverter vibration properties contain information relevant for early fault detection.

  • 48.
    Källström, Elisabeth
    et al.
    Lulea University of Technology ; Volvo Construction Equipment.
    Olsson, Tomas
    RISE SICS .
    Lindström, John
    Lulea University of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    Larsson, Jonas
    Volvo Construction Equipment.
    On-board Clutch Slippage Detection and Diagnosis in Heavy Duty Machine2018In: International Journal of Prognostics and Health Management, E-ISSN 2153-2648, Vol. 9, no 1, p. 1-14, article id 007Article in journal (Refereed)
    Abstract [en]

    In order to reduce unnecessary stops and expensive downtime originating from clutchfailure of construction equipment machines; adequate real time sensor data measured on the machine in combination with feature extraction and classification methods may be utilized.

    This paper presents a framework with feature extraction methods and an anomalydetection module combined with Case-Based Reasoning (CBR) for on-board clutch slippagedetection and diagnosis in heavy duty equipment. The feature extraction methods used are Moving Average Square Value Filtering (MASVF) and a measure of the fourth order statistical properties of the signals implemented as continuous queries over data streams.The anomaly detection module has two components, the Gaussian Mixture Model(GMM) and the Logistics Regression classifier.CBR is a learning approach that classifies faults by creating a new solution for a new fault case from the solution of the previous fault cases.Through use of a data stream management system and continuous queries (CQs), the anomaly detection module continuously waits for a clutch slippage event detected by the feature extraction methods, the query returns a set of features, which activates the anomaly detection module. The first component of the anomaly detection module trains a GMM to extracted features while the second component uses a Logistic Regression classifier for classifying normal and anomalous data. When an anomaly is detected, the Case-Based diagnosis module is activated for fault severity estimation.

  • 49.
    Larsson, Martin
    et al.
    Blekinge Institute of Technology.
    Johansson, Sven
    Blekinge Institute of Technology.
    Claesson, Ingvar
    Blekinge Institute of Technology.
    Håkansson, Lars
    Blekinge Institute of Technology.
    A Module Based Active Noise Control System for Ventilation Systems, Part II: Performance Evaluation2009In: International Journal of Acoustics and Vibration, ISSN 1027-5851, E-ISSN 2415-1408, Vol. 14, no 4, p. 196-206Article in journal (Refereed)
    Abstract [en]

    To utilize the full noise-attenuation potential of an active noise control (ANC) system applied to duct noise, it is important to be able to minimize the turbulence-induced noise in the microphone signals. This is the second paper in a series of two, that treats the problem of turbulence-induced noise originating from the airflow inside the ducts, when applying ANC to ducts. Part I contains theoretical and experimental investigations of the influence of the turbulence-induced noise on the filtered-x LMS algorithm used in the ANC system. Part II (the present paper) is concerned with the design and investigations of microphone installations, which produce a sufficient amount of turbulence suppression while also meeting industry requirements. These requirements are, for example, that the microphone installations should be based on standard ventilation parts, and that they should be easily installed and maintained. Furthermore, results concerning the performance of an ANC system with different microphone installations are presented. Some of the results were obtained at an acoustic laboratory according to an ISO standard. The attenuation achieved with ANC was approximately 15-25 dB between 50-315 Hz, even for airflow speeds up to 20 m/s.

  • 50.
    Larsson, Martin
    et al.
    lekinge Institute of Technology.
    Johansson, Sven
    lekinge Institute of Technology.
    Claesson, Ingvar
    lekinge Institute of Technology.
    Håkansson, Lars
    lekinge Institute of Technology.
    A Module Based Active Noise ControlSystem for Ventilation Systems, Part I: Influence of Measurement Noise on the Performance and Con-vergence of the Filtered-x LMS Algorithm2009In: International Journal of Acoustics and Vibration, ISSN 1027-5851, E-ISSN 2415-1408, Vol. 14, no 4, p. 188-195Article in journal (Refereed)
    Abstract [en]

    Low noise level is an essential feature when installing ventilation systems today. To achieve attenuation over a broad frequency range, the passive silencers traditionally used to attenuate ventilation noise can be combined with an active noise control (ANC) system. To insure reliable operation and desirable levels of attenuation when applying ANC to duct noise, it is highly important to be able to suppress the contamination of the microphone signals due to the turbulent pressure fluctuations, which arise as the microphones are exposed to the airflow in the duct. This paper is the first in a series of two regarding the problem of turbulence-induced noise originating from the airflow inside the ducts. Part I is concerned with theoretical and experimental investigations of the influence of the turbulence-induced noise on the adaptive algorithm in the ANC system. Part II is concerned with the design and the investigations of microphone installations for turbulence suppression and the results concerning the performance of an ANC system with the different microphone installations are presented. Some of the results were obtained at an acoustic laboratory according to an ISO-standard. The attenuation achieved with ANC was approximately 15-25 dB between 50-315 Hz, even for airflow speeds up to 20 m/s

12 1 - 50 of 61
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf