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  • 51.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Modelling and control of a rotary crane1995In: Proceedings of the Third European Control Conference: ECC 95, 1995, Vol. pt. 4, vol.4, p. 3805-3810Conference paper (Refereed)
    Abstract [en]

    This paper deals with the feedback control of a rotary crane. The goal is to design a control system that assists the operator to move the cargo without oscillations and correctly align the cargo at the final position. This is accomplished by a weakly coupled pair of state feedback controllers with a nonlinear compensator.

  • 52.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Modelling and control of rotary crane systems1993Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is devoted to the modelling and control of rotary crane systems. The goal is to design a control system that assists the operator to move a cargo without oscillations and to correctly align the cargo at the final position. The control system is divided into two independent parts, one dealing with the alignment of the load with the aid of a power swivel or a cargo rotating device, and a second that deals with the elimination of load oscillations. Both design and implementation of the control algorithms on a full scale crane are considered. In the cargo alignment system a linear cascade controller is considered that is shown to have near time-optimal performance for a system with saturation in both the angle and the angular rate of the power swivel. In the second part a weakly coupled pair of state feedback controllers with a nonlinear compensator is used to eliminate the load oscillations in two dimensions. In the third part of the thesis a software tool for simulation and real time control is presented. The development of the program started as a spin-off to the crane projects.

  • 53.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Monitoring and fault detection in networked control systems2006Conference paper (Other academic)
  • 54.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    När kranföraren blir en belastning2004Conference paper (Other academic)
    Abstract [sv]

    Vad måste man tänka på när en människa finns inne i reglerloopen? Vilka möjligheter ger det och vilka begränsningar innebär det. Uppgiften för en kranförare på en hamnkran är att med hög precision så snabbt som möjligt flytta en container från en plats till en annan. Detta är ett krävande jobb i en tuff arbetsmiljö som ställer höga krav på både koncentration, och skicklighet. I en stor hamnkran så åker kranföraren med i trallan. Med reglertekniska termer så är kranföraren både sensor och regulator. Trallan är ställdonet. Inför vi automation så kan det i sämsta fallet leda till att en kranförare utsätts för krafter som kan vara både oförutsägbara och kraftiga. Vi sammanställer erfarenheter från automatisering av far- tygskranar, hamnkranar och olika typer av terminalkranar.

  • 55.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    On the design and implementation of a rotary crane controller1996In: European Journal of Control, ISSN 0947-3580, E-ISSN 1435-5671, Vol. 2, no 2, p. 166-175Article in journal (Refereed)
  • 56.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Projekt: Robust reglering av pelletsbrännare2008Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Förstudien genomförs i två arbetspaket med följande innehållWP1 Grundläggande labstudie – En experimentell kampanj genomf¨ors av Energiteknikd¨ar vi unders¨oker kopplingen mellan lokala fluktuationer i br¨ansle inmatningenoch andra processparametrar som temperaturen i b¨adden, flamman ochr¨okgaserna och koncentrationen av O2, CO2, CO, tyngre kolv¨aten och partiklar.Ett antal sensorer kommer att inf¨orskaffas samt testas i olika positioner ien pelletspanna/br¨annare. Driften av br¨annaren kommer att provoceras genomatt f¨or¨andra br¨anslekvalit´en, luftm¨angden samt lasten. Sensorer som kan kommaatt testas ¨ar temperatursensorer, trycksensorer samt gassensorer f¨or CO,O2 samt NOx. Temperaturer som kan m¨atas ¨ar olika f¨orbr¨anningstemperaturer(b¨add, flamma osv) samt r¨okgastemperaturer. Informationen fr °an sensorernautv¨arderas och anv¨andas f¨or att hitta sambanden mellan sensorernas signalersamt f¨orbr¨anningskarakteristik. M° alet med f¨ors¨oken ¨ar att identifiera billigasensorer, dess antal samt dess m¨atpositioner f¨or att p°a ett bra vis kunna karakt¨arisera samt styra f¨orbr¨anningsprocessen. Baserat p°a denna studie kommerett antal sensorer att v¨aljas ut f¨or vidare utveckling av styrstrategier samt tester.WP2 Processmodeller och reglering – De modeller som anv¨ands inom f¨orbr¨anningsteknik¨ar s¨allan direkt anv¨andningsbara f¨or att dimensionera konventionella regulatorer.P°a senare tid har det utvecklats en hel del nya metoder f¨or regleringsom vidgar m¨ojliheterna att anv¨anda olika typer av modeller. I detta arbetspakets °a tittar vi p°a hur befintliga f¨orbr¨anningstekniska modeller och de modeller somutvecklas i WP1 kan modifieras f¨or att p°a b¨asta s¨att ligga till grund f¨or analysoch syntes olika typer av regulatorer.Baserat p°a dessa anpassade modeller s °a utv¨arderas ett antal olika m¨ojliga reglerstrategier.I detta ing ° ar det att analysera hur os¨akerheter i modellerna, olikakonfigurationer av sensorer och aktuatorer, p°averkar vilken verkningsgrad ochmilj¨op°averkan som ¨ar teoretiskt m¨ojligt att uppn°a med olika typer av givare.F¨or att m¨ojligg¨ora en framtida ¨overvakning och trimning p°a distans s °a kommerm¨ojligheterna f¨or extern kommunikation och ¨overvakning att studeras

  • 57.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Regsim: a software tool for real time control and simulation1995In: Proceedings of the 4th IEEE Conference on Control Applications: The Desmond Hotel, Albany, New York, September 28 - 29, 1995, Piscataway, NJ: IEEE Communications Society, 1995, p. 168-173Conference paper (Refereed)
    Abstract [en]

    This paper presents a software tool, Regsim, that bridges the gap between simulation and real world experiments of control systems. The ideas behind Regsim are that it should be interactive, easy to use and that it should behave uniformly irrespective of the use, whether it is simulation or real-time control.

  • 58.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Tillämpningar av rekursiv estimering1984Licentiate thesis, comprehensive summary (Other academic)
  • 59.
    Gustafsson, Thomas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Andersson, Ulf
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Broström, Fredrik
    Bortolin, Gianantoni
    Volvo CE, Sverige.
    Projekt: Optimerad framkomlighet för tunga terrängfordon2011Other (Other (popular science, discussion, etc.))
    Abstract [en]

    This project is aimed at improving traction control characteristics for wheel loaders and haulers. At present, drivers of these machines can choose between open or closed differentials but often they prefer to lock the differentials, thus distributing the torque equally between the wheels and thereby almost always avoiding wheel slip. However, locked differentials cause increased wear of the driveline, increased fuel consumption and greater tyre wear. Therefore it is worthwhile to investigate other solutions such as limited slip differentials or differentials with a clutch where the torque is distributed as necessary among the driving wheels.

  • 60.
    Gustafsson, Thomas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Björkman, Eric
    Coldbay AB.
    Förfarande och system för torkning av virke i ett torkutrymmePatent (Other (popular science, discussion, etc.))
  • 61.
    Gustafsson, Thomas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Broström, Fredrik
    Projekt: Optimal dragkraftsreglering för anläggningsmaskiner2014Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Projektet syftar till att förbättra dragkraftsreglering och minska slirning av hjul vid körning med arbetsmaskiner. projketet kommer fokusera på en elektrisk drivlina för hjullastatare och dumprar men är direkt användbart för andra typer av fordon med elektrisk drivlina. Huvudleverablerna från projektet kommer vara ökad förståelse för dragkrafsreglering vid elektrisk drivlina och förbättrade kontrollalgoritmer för densamma. Projektet kommer bidra till en minskad bränsleförbrukningen och slitage på däck.

  • 62.
    Gustafsson, Thomas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Heidenback, Claes
    Asea Industries / Crane Systems.
    Automatic control of unmanned cranes at the Pasir Panjang terminal2002In: Proceedings of the 2002 International Conference on Control Applications: September 18 - 20, 2002, Scottish Exhibition and Conference Centre, Glasgow, Scotland, U.K., Piscataway, NJ: IEEE Communications Society, 2002, p. 180-185Conference paper (Refereed)
    Abstract [en]

    The overhead bridge cranes (OHBC) at the Pasir Panjang terminal in the Port of Singapore are operated remotely. Each operator can handle up to six cranes. This is possible due to the highly automated system that controls the cranes. This paper describes the control system that is implemented in the terminal.

  • 63.
    Gustafsson, Thomas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Salehpour, Soheil
    Projekt: Modellering av komplexa dynamiska system2007Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    En processindustrianläggning karaktäriseras av många delprocesser som är kopplade genom t.ex. materialflöden, gemensamma resurser, regulatorer osv. Detta förhållande ger upphov till tre typer av problem. 1. Det stora antalet processvariabler gör det orimligt att lägga ner stora arbetsinsatser på varje enskild variabel för t.ex. regulatordesign och övervakning. 2. De dynamiska kopplingarna mellan processvariablerna gör anläggningen till ett enormt stort dynamiskt system som inte är realistiskt att hantera som en helhet vid design av regulatorer och övervakningsalgoritmer. 3. Den komplexa strukturen kan ge upphov till komplicerad och svårförutsägbar dynamik i anläggningen som helhet, vilket kan ge upphov till t.ex. oscillationer. Arbetet i projektet fördelas på tre arbetspaket som angriper delproblem under de tre punkterna ovan. Alla tre arbetspaket förväntas resultera i verktyg som i förlängningen kan ingå som värdefulla komponenter på den plattform som en operatörssimulator utgör.

  • 64.
    Gustafsson, Thomas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Sayyaddelshad, Saleh
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Björkman, Eric
    Alent Drying AB, Sverige.
    Projekt: Optimal styrning av virkestorkning2012Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    På ett sågverk kan det finnas mer än fyrtio virkestorkar som körs samtidigt. De förses värme från en gemensam värmepanna och restvärmen som inte förbrukas kan användas för att producera elenergi. Den långsiktiga målsättningen är att ta fram ett överordnat system som kan minimera energiförbrukningen med bibehållen torkkvalitet för en grupp av virkestorkar. Systemet skall även klara av att möta de krav på variation i restvärme som kommer från den efterföljande produktionen av elenergi.

  • 65.
    Hyyppä, Kalevi
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    PBL at Luleå University of Technology1995In: Proceedings: International conference on problem-based learning in higher education, September 24-27 1995 Linköping, Sweden, Linköping: Linköping universitet , 1995Conference paper (Refereed)
  • 66.
    Hyyppä, Kalevi
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Wernersson, Åke
    Andersson, Ulf
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Navigeringsexperiment med autonomt fordon1991In: Robotikdagar: robotteknik och verkstadsteknisk automation mot ökad autonomi ; 30 - 31 maj 1991, Linköping ; proceedings, Linköping, 1991Conference paper (Refereed)
  • 67.
    Hyyppä, Kalevi
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Wiklund, Urban
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Andersson, Ulf
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Wernersson, Åke
    Hillerström, Gunnar
    Zell, Caj
    Navigational experiments with the autonomous mobile robot ltt using angle measurements to identical beacons1994In: International Conference on Machine Automation: mechatronics spells profitability. Proceedings of the ICMA'94, Tampere University of Technology, 1994Conference paper (Refereed)
  • 68.
    Jafari, Hedyeh
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Castaño Arranz, Miguel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    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.
    On Control Structure Design for a Walking Beam Furnace2017In: 2017 25th Mediterranean Conference on Control and Automation, MED 2017, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1355-1360, article id 7984307Conference paper (Refereed)
    Abstract [en]

    The aim of this article is to introduce a novel sparse controller design for the temperature control of an experimental walking beam furnace in steel industry. Adequate tracking of temperature references is essential for the quality of the heated slabs. However, the design of the temperature control is hindered by the multivariable (non-square) dynamic behavior of the furnace. These dynamics include significant loop interactions and time delays. Furthermore, a novel data-driven model, based on real life experimental data that relies on a subspace state representation in a closed loop approach is introduced. In the sequel, the derived model is utilized to investigate the controller's structure. By applying the relative gain array approach a decentralized feedback controller is designed. However, in spite of the optimal and sparse design of the controller, there exists interaction between loops. By analyzing the interaction between the inputs-outputs with the Σ2 Gramian-based interaction methodology, a decoupled multi-variable controller is implied. The simulation result, based on the experimental modeling of the furnace, shows that the controller can successfully decrease the interaction between the loops and track the reference temperature set-points.

  • 69.
    Jafari, Hedyeh
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Stabilization of an Inverted Pendulum via Human Brain Inspired Controller Design2019Conference paper (Refereed)
  • 70.
    Jafari, Hedyeh
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Pauelsen, Mascha
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Röijezon, Ulrik
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Nyberg, Lars
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Nikolakopoulos, George
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A novel data driven model of ageing postural control2019Conference paper (Refereed)
    Abstract [en]

    Background

    Postural control is a complex system. Based on sensorimotor integration, the central nervous system (CNS) maintains balance by sending suitable motor commands to the muscles. Physiological decline due to ageing, affects balance performance through failing postural control – and in turn affects falls self-efficacy and activity participation. Understanding how the CNS adapts to these changes and predicts the appropriate motor commands to stabilize the body, has been a challenge for postural control research the latest years.

    Aims

    To understand and model the performance of the central nervous system as the controller of the human body.

    Methods

    Modelling was based on postural control data from 45 older adults (70 years and older). Ankle, knee and hip joint kinematics were measured during quiet stance using a motion capture system. Principal component analysis was used in order to reduce the measured multidimensional kinematics from a set of correlated discrete time series to a set of principal components. The outcome was utilized to predict the motor commands. The adaptive behaviour of the CNS was modelled by recurrent neural network including the efference copy for rapid predictions. The data from joint kinematics and electromyography (EMG) signals of the lower limb muscles were measured and separated into training and test data sets.

    Results

    The model can predict postural motor commands with very high accuracy regardless of a large physiological variability or balancing strategies. This model has three characteristics: a) presents an adaptive scheme to individual variability, 2) showcases the existence of an efference copy, and 3) is human experimental data driven.

    Conclusion

    The model can adapt to physical body characteristics and individual differences in balancing behaviour, while successfully predict motor commands. It should therefore be utilised in the continued pursuit of a better understanding of ageing postural control.

  • 71.
    Jafari, Hedyeh
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Pauelsen, Mascha
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Röijezon, Ulrik
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Nyberg, Lars
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Nikolakopoulos, George
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    On Internal Modeling of the Upright Postural Control in Elderly2018Conference paper (Refereed)
  • 72.
    Kadhim, Ali
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Calculation of Relative Gain Array Based on Nonparametric Process Identification: A Frequency Domain Approach2014Conference paper (Other academic)
  • 73.
    Kadhim, Ali
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Evaluation of vehicle tracking for traffic monitoring based on road surface mounted magnetic sensors2013In: The Third IFAC Symposium on Telematics Applications (TA 2013)Applications: November 11‒13, 2013, Yonsei University, Seoul, Korea / [ed] Jang-Won Lee, Red Hook, NY: Curran Associates, Inc., 2013, p. 13-18Conference paper (Refereed)
    Abstract [en]

    The aim of this work is to evaluate a vehicle tracking scheme as a means of monitoring traffic on roads. The scheme can be used as a component in a traffic monitoring system which can provide traffic management systems and road maintainers with traffic information. Vehicle tracking is achieved by determining vehicle position, velocity and magnetic moment using a nonlinear weighted least squares method (NWLS) on readings from two 3-axes magnetic sensors.The tracking was performed both in simulation and in real life. The traffic monitoring system is composed of two adjacently glue attached wireless sensor nodes, which are placed at a distance of 1 m along the road. A potential misalignment of the sensors due to placement errors is analysed in simulation and addressed.

  • 74.
    Kadhim, Ali
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Relative gain array estimation based on non-parametric frequency domain system identification2014Conference paper (Refereed)
  • 75.
    Kadhim, Ali
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Relative Gain Array Estimation Based on Non-Parametric Frequency Domain System Identification2014In: 2014 IEEE International Conference on Control Applications (CCA 2014): Juan Les Antibes, France, 8 -10 October 2014, Piscataway, NJ: IEEE Communications Society, 2014, p. 110-115Conference paper (Refereed)
    Abstract [en]

    Since the introduction of the Relative Gain Array (RGA) by Bristol in 1966, it has received a high level of attention as a practical tool for solving the input-output pairing problem in decentralized control. Moreover, many extensions have been proposed like e.g. for the dynamic case and non-square system matrices. Recently, extensions that provide tools for uncertain parametric process models were suggested. In order to removethe dependency of these tools on a parametric description and accurate knowledge of a nominal model this paper proposes a method to calculate the RGA directly from a non-parametric frequency response matrix (FRM), derived from frequency domain system identification approach. The proposed method reduces the influence of model uncertainties on the calculation of the RGA and derives the RGA at frequencies of interest. Using Monte-Carlo principles, the variance of the estimated RGA is derived and compared with recently proposed methods. The results are exemplified on 2 by 2, 2 by 3 and 3 by 3 systems. It concluded that the proposed methods performs well and robust, while simplifying the estimation of the RGA.

  • 76.
    Kadhim, Ali
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Relative Gain Array Estimation Based on Non-parametric Process Identification for Uncertain Systems2015Conference paper (Other academic)
    Abstract [en]

    Since the introduction of the Relative Gain Array (RGA) by Bristol in 1966, it has become awidely used practical tool for solving the input-output pairing problems in decentralized control. In order to remove the dependency of this tool on a parametric description and accurate knowledge of a nominal model, this work proposes a method to estimate the RGA directly from a non-parametric frequency response matrix (FRM) derived from a frequency domain system identification approach. The proposed method reduces the influence of model uncertainties on the calculation of the RGA and derives the RGA at frequencies of interest. The results are exemplified using a 2x3 LTI systems and a 2x2 uncertain system.

  • 77.
    Kadhim, Ali
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Relative Gain Array Variation for Norm Bounded Uncertain Systems2015In: IEEE 54th Annual Conference on Decision and Control (CDC): Osaka, Japan, 15-18 Dec. 2015, Piscataway, NJ: IEEE Communications Society, 2015, p. 5959-5965, article id 7403156Conference paper (Refereed)
    Abstract [en]

    This article proposes computationally tractable, easyto expand and tight relative gain variation bound for uncertain systems. The proposed bound is a further development of previous work, which is summarized anddiscussed. Using several examples, the new method is compared with previous results and the advantages are highlighted. The prediction of sign changes in relative gain array elements due to uncertainties is important for pairing decisions. Based on the proposed bound,a method for the prediction of the uncertainty levels which render sign changes is suggested. The prediction method is currently limited to certain classes of systems.In this prediction method neither prior knowledge of the uncertainty nor numerous calculations are needed.

  • 78.
    Kadhim, Ali
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Castano, Miguel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Relative Gain Array of Weakly Nonlinear Systems using a Nonparametric Identification Approach2015In: 2015 IEEE International Conference on Control Applications (CCA 2015): Sydney, Australia, September 21-23, Piscataway, NJ: IEEE Communications Society, 2015, p. 1612-1617, article id 7320840Conference paper (Refereed)
    Abstract [en]

    This article presents a procedure to estimate the relative gain array (RGA) matrix for weakly nonlinear systems by means of nonparametric identification of the frequency response matrix (FRM). Specifically, the best linear approximation of nonlinear systems and the covariance of the nonlinear distortions are used in the relative gain array estimation. For the estimation neither process model nor model structure need to be known which is an advantage over methods that require accurate knowledge of a parametric process model. The proposed approach is compared with the original RGA and a nonlinear RGA calculation using the well-known quadruple tank process as a case

  • 79. Larsson, John Erik
    et al.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Paper machine dry line position control during grade changes1998In: Proceedings of the 1998 American Control Conference: ACC, June 24 - 26, 1998, Philadelphia, Pennsylvania, USA, Piscataway, NJ: IEEE Communications Society, 1998, p. 2997-3001Conference paper (Refereed)
    Abstract [en]

    The detection and control of the dry line machine direction position on a fourdrinier paper machine are considered. The dry line position is detected using a digital image processing system consisting of a CCD camera, a frame grabber and a standard PC. The system was installed on a kraft liner machine and both open loop and closed loop experiments were performed with encouraging results. The introduction of automatic control of the dry line position reduces the time for grade changes and it also reduces the machine operators work load. The reduced time leads to smaller production losses and hence to economical benefits.

  • 80. Larsson, John Erik
    et al.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Rönnbäck, Stefan
    Paper machine dry line position control1998In: Reglermöte '98: preprints, Lund: Reglerteknik, Lunds tekniska högskola , 1998, p. 168-172Conference paper (Other academic)
  • 81. Larsson, John Erik
    et al.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Rönnbäck, Stefan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Paper machine dry line positioning system1998In: Proceedings of Control Systems 98, Finnish Society of Automation , 1998, p. 355-362Conference paper (Refereed)
  • 82.
    Larsson, Ulf
    et al.
    Luleå tekniska universitet.
    Jannok, D.
    Luleå tekniska universitet.
    Sandberg, U.
    Luleå tekniska universitet.
    Åhman, P.
    Luleå tekniska universitet.
    Franzén, M.
    Luleå tekniska universitet.
    Nilsson, R.
    Luleå tekniska universitet.
    Wernersson, Åke
    Hyyppä, Kalevi
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Calman : computerized articulated lawn mower with automatic navigation1993In: Proceedings: Robotikdagar 2-3 juni 1993 : automatiserad tillverkning - från högteknologi till tillämpning : Robotics Workshop, Linköping 1993, Linköping: Linköping University Electronic Press, 1993Conference paper (Refereed)
  • 83.
    Lindgren, Thore
    et al.
    Luleå tekniska universitet.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Forsgren, Harry
    Eurocon AB, Örnsköldsvik.
    Johansson, Daniel
    Luleå tekniska universitet.
    Östensson, Jan
    M-real, Husum Mill, Husum.
    Model predictive control of the chip level in a continuous pulp digester2004In: Control Systems 2004 Conference: preprints, Pulp and Paper Tech. Assoc. of Canada , 2004, p. 5-11Conference paper (Refereed)
    Abstract [en]

    This paper describes the implementation of a digester chip level control system at the M-real Husum mill and an analysis of the chip level control problem. The kappa number variability is strongly related to variability in chip transport conditions which is related to the variations in chip retention time, caused by fluctuations in chip packing, blow line consistency, etc. It is important for a uniform pulp quality to have a stable movement of the chip column and stable properties in digester bottom. The objective with implemented chip level control system is to stabilize the transport conditions in the bottom of the digester by using the chip feed and not the blow flow (original control system) as the primary manipulated variable. The results indicate a smoother digester operation and a reduction of kappa number variations. The level control strategy is implemented both as a MPC controller scheme on a stand alone PC and as a conventional PID-solution in the DCS system

  • 84.
    Lindgren, Thore
    et al.
    Luleå tekniska universitet.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Forsgren, Harry
    Eurocon AB, Örnsköldsvik.
    Johansson, Daniel
    M-real, Husum Mill, Husum.
    Östensson, Jan
    M-real, Husum Mill, Husum.
    Model predictive control of the chip level in a continuous pulp digester: a case study2005In: Pulp & paper Canada, ISSN 0316-4004, Vol. 106, no 11, p. 45-51Article in journal (Refereed)
    Abstract [en]

    This paper describes the digester chip level control problem and shows a MPC system implementation for the level control. The objective with implemented chip level control system is to stabilize the transport conditions in the bottom of the digester by using the chip feed and not the blow flow as the primary manipulated variable. The results indicate a smoother digester operation and a reduction of the kappa number variations compared with the original control system

  • 85.
    Lindström, John
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Impact on production systems from recent and emerging complex business models: Explicit and tacit knowledge required2015In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 38, p. 210-215Article in journal (Refereed)
    Abstract [en]

    The paper addresses, based on an empirical study, what impact the use of recent complex business models, in particular, Functional Products, may have on production systems in terms of the explicit and tacit knowledge that is required. Requirements for new knowledge currently lacking or in the process of being acquired have been of specific interest for the study. The study focuses on the customer side, involving both manufacturing and process industry companies. A set of explicit and tacit knowledge aspects has been identified. The current set of knowledge aspects found during the literature review has largely been corroborated and the new specific knowledge identified is highlighted.

  • 86.
    Mamikoglu, Umut
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Andrikopoulos, Georgios
    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.
    Röijezon, Ulrik
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Pauelsen, Mascha
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Electromyography Based Joint Angle Estimation and Control of a Robotic Leg2016In: 6th IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob 2016): June 26-29, Singapore, 2016, Piscataway, NJ: IEEE Communications Society, 2016, p. 182-187, article id 7523619Conference paper (Refereed)
    Abstract [en]

    Musculoskeletal modeling based on Electromyography (EMG) has many applications in physiotherapy and biologically-inspired robotics. In this article, a novel methodology for the modeling of the dynamics of an antagonistic muscle pair that actuates the human ankle joint movements will be established. As it will be presented, the musculoskeletal model is based on a multi input single output (MISO) auto-regressive integrated moving average with exogenous input (ARIMAX) model, which takes the integrated EMG measurements as input and estimates the corresponding joint angles. Based on this methodology, a Pneumatic Artificial Muscle (PAM) robotic leg setup that mimics the flexion/extension movement of human ankle joint is controlled to replicate the human movement. The experimental results demonstrate the performance of EMG based joint angle estimation and control of the robotic leg with the proposed model.

  • 87.
    Mamikoglu, Umut
    et al.
    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.
    Pauelsen, Mascha
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Varagnolo, Damiano
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Röijezon, Ulrik
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Elbow Joint Angle Estimation by Using Integrated Surface Electromyography2016In: 24th Mediterranean Conference on Control and Automation (MED): June 21-24, Athens, Greece, 2016, Piscataway, NJ: IEEE Communications Society, 2016, p. 785-790, article id 7535891Conference paper (Refereed)
    Abstract [en]

    Electromyography (EMG) signals represent the electrical activation of skeletal muscles and contain valuable information about muscular activity. Estimation of the joint movements by using surface EMG signals has great importance as a bio-inspired approach for the control of robotic limbs and prosthetics. However interpreting surface EMG measurements is challenging due to the nonlinearity and user dependency of the muscle dynamics. Hence it requires complex computational methods to map the EMG signals and corresponding limb motions. To solve this challenge we here propose to use an integrated EMG signal to identify the EMG-joint angle relation instead of using common EMG processing techniques. Then we estimate the joint angles for elbow flexion-extension movement by using an auto-regressive integrated moving average with exogenous input (ARIMAX) model, which takes integrated EMG measurements as input. The experiments showed that the suggested approach results in a 21.85% average increase in the estimation performance of the elbow joint angle compared to the standard EMG processing and identification.

  • 88.
    Mansouri, Sina Sharif
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Georgoulas, Georgios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    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.
    On the covering of a polygonal region with fixed size rectangles with an application towards aerial inspection2017In: 2017 25th Mediterranean Conference on Control and Automation, MED 2017, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1316-1320, article id 7984300Conference paper (Refereed)
    Abstract [en]

    Unmanned Aerial Vehicles (UAVs) equipped with remote visual sensing can be used in wide range of applications. However, guaranteeing the full coverage of the area and translating this coverage in a path planning problem, it is a quite challenging task. Thus, in this article a well-known and well-investigated family of hard optimization problems, covering a polygonal region (target area) with fixed size rectangles (camera frustrum), is studied. The problem is formulated mathematically and solved using metaheuristic optimization algorithms. The proposed novel algorithmic scheme requires an a priori 2D model of the target area, while it tries to maximize the coverage with a minimum number of fixed size rectangles. Finally, multiple simulation results are presented that prove the efficacy of the proposed scheme

  • 89.
    Mansouri, Sina Sharif
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Kanellakis, Christoforos
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Georgoulas, Georgios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Kominiak, Dariusz
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    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.
    2D visual area coverage and path planning coupled with camera footprints2018In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 75, p. 1-16Article in journal (Refereed)
    Abstract [en]

    Unmanned Aerial Vehicles (UAVs) equipped with visual sensors are widely used in area coverage missions. Guaranteeing full coverage coupled with camera footprint is one of the most challenging tasks, thus, in the presented novel approach a coverage path planner for the inspection of 2D areas is established, a 3 Degree of Freedom (DoF) camera movement is considered and the shortest path from the taking off to the landing station is generated, while covering the target area. The proposed scheme requires a priori information about the boundaries of the target area and generates the paths in an offline process. The efficacy and the overall performance of the proposed method has been experimentally evaluated in multiple indoor inspection experiments with convex and non convex areas. Furthermore, the image streams collected during the coverage tasks were post-processed using image stitching for obtaining a single overview of the covered scene.

    The full text will be freely available from 2020-06-01 11:15
  • 90.
    Mansouri, Sina Sharif
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Distributed Model Predictive Control for Unmanned Aerial Vehicles2015In: 2015 Workshop on Research, Education and Development of Unmanned Aerial Systems: RED-UAS 2015, Cancun, Mexico, 23 - 25 November 2015, Picataway, NJ: IEEE Communications Society, 2015, p. 152-161, article id 7441002Conference paper (Refereed)
    Abstract [en]

    In this article a distributed model pre- dictive control scheme, for the cooperative motion control of Unmanned Aerial Vehicles (UAVs) is be- ing presented. The UAVs are modeled by a 6-DOF nonlinear kinematic model. Two different control ar- chitectures: a centralized and a distributed MPC, are studied and evaluated in simulation experiments. In the centralized approach, one central MPC controller is responsible for the movement coordination of all the UAVs, while in the distributed approach each aerial vehicle plans only for its own actions, while the objective function is coupled with the behavior of the rest of the team members and the constraints are decoupled. In this approach, each agent only shares the future position of itself with the other agents to avoid collisions. For reducing the computation time and complexity, only one step ahead prediction in the corresponding MPC schemes have been considered without a loss of generality. Finally, the efficiency of the overall suggested decentralized MPC scheme, as well as it comparison with the centralized approach, is being evaluated through the utilization of multiple simulation scenarios.

  • 91.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A fault diagnosis scheme for three phase induction motors based on uncertainty bounds2012In: IECON 2012: 38th Annual Conference of the IEEE Industrial Electronics Society, Piscataway, NJ: IEEE Communications Society, 2012, p. 1596-1601Conference paper (Refereed)
    Abstract [en]

    The aim of this article is to present a fault diagnosis scheme for the case of squirrel–cage Three Phase Induction Motors based on uncertainty bounds violation conditions. The suggested scheme has the capability to diagnose two types of faults: a) broken rotor bar and b) short circuit in stator winding. The fault diagnosis is being performed through a two steps procedure. In the first step the parameters of the healthy induction motor are being identified by utilizing a Set Membership Identification approach, where corresponding uncertainty bounds are also being provided. In the second step, specific proposed bound violation conditions for the fault detection and fault diagnosis are being on–line evaluated during a sliding time window. Multiple simulation results are being presented that prove the efficacy of the proposed scheme towards fault detection and fault diagnosis.

  • 92.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A Robust Linear Discrimination Fault Classification Scheme for Three Phase Induction Motors2013In: CoDIT 2013: IEEE 2013 International Conference on Control, Decision and Information Technologies, Piscataway, NJ: IEEE Communications Society, 2013, p. 524-529Conference paper (Refereed)
    Abstract [en]

    In this article a fault classification algorithm based on a robust linear discrimination scheme, for the case of a squirrel–cage three phase induction motor, will be presented. The suggested scheme is based on a novel feature extraction mechanism from the measured magnitude and phase of current park’s vector pattern. The proposed methodology has the merit to diagnose different types of faults such as: a) broken rotor bar, and b) short circuit in stator winding. The novel feature generation technique is able to transform the problem of fault detection and diagnosis into a simpler space, where direct robust linear discrimination can be applied for solving the classification problem. Robust linear discrimination has been one of the most widely used fault detection method in real life applications, as this methodology seeks for directions that are efficient for discrimination and at the same time requires a straight forward implementation. The efficacy of the proposed scheme will be evaluated based on multiple simulation results for different fault types.

  • 93.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A survey on modeling approaches for three phase induction motors2012In: Proceedings of the IASTED International Conference on Modelling, Simulation and Identification / [ed] T. Znati; Z. Bar-Joseph; L. Rothrock, ACTA Press, 2012, p. 336-343Conference paper (Refereed)
    Abstract [en]

    Three–phase induction machines are generally being utilized as motors for many industrial systems, mainly due to their simple construction, low cost and other merits, when compared with other types of motors. The main aim of this article is to present a survey regarding the appeared approaches towards the mathematical modeling of three phase induction motors, which is the first step before designing appropriate control schemes. More analytically, two main modeling approaches will be presented: a) the complete three phase models, and b) the simplified quadra-ture phase models. Within these two main categories, all the types of the modeling approaches for induction motors will be presented, while the relevant significant applications, including the corresponding advantages and disadvantages for these models will be also presented. Finally, an extended bibliography is being provided as a base line for future investigations.

  • 94.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Broken Bars Fault Diagnosis Based on Uncertainty Bounds Violation for Three Phase Induction Motors2015In: International Transactions on Electrical Energy Systems, E-ISSN 2050-7038, p. 304-325Article in journal (Refereed)
    Abstract [en]

    In this article, a novel fault diagnosis scheme, based on uncertainty bounds violation, is being presented for the case of broken bars in squirrel–cage Three Phase Induction Motors. The fault diagnosis is done in two steps. Firstly the parameters of the healthy induction motor are identified using a set member- ship identification (SMI) approach, where corresponding uncertainty bounds are also being provided. Secondly the proposed uncertainty bounds violation conditions for the fault diagnosis are evaluated on–line, on the converged identified model, during a sliding time window. Multiple simulation results are presented that demonstrate the efficacy of the proposed scheme towards fault detection and diagnosis among different number of broken bars.

  • 95.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Broken rotor bar fault detection based on uncertainty ellipsoidal intersection for three phase induction motors2013In: 21st IEEE Mediterranean Conference on Control and Automation, June 25-28, Platanias, Chania, Crete, Greece, 2013., Piscataway, NJ: IEEE Communications Society, 2013, p. 388-393, article id 6608751Conference paper (Refereed)
    Abstract [en]

    In this article a fault detection scheme for broken rotor bar fault detection in three phase induction motor is presented. In the proposed scheme the induction motor has been transformed in the equivalent two phase (q−d) space, while the modeling of the faulty case has been also formulated. The model has been identified by the utilization of the Set Membership Identification (SMI) algorithm that has the merit of identifying both the parameters of the motor as also providing uncertainty bounds in both the healthy and the faulty cases. Based on the adopted methodology, the uncertainty bounds and the corresponding identified parameters of the induction motor is presented as 3D–ellipsoids, while a novel fast and efficient fault detection scheme has been proposed that is able to track iteratively the ellipsoid centers, the distance among centers, the intersection between the initial and a priori known converged states of the motor and the current ones, before or after the fault occurrence. Detailed analysis of the proposed approach and he fault detection strategy, as also extended simulation results are being presented that prove the efficiency of the suggested scheme.

  • 96.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Experimental evaluation of a broken rotor bar fault detection scheme based on uncertainty bounds violation2013In: 39th Annual Conference of the IEEE Industrial Electronics Society: November 10-13, 2013, Vienna, Austria, IEEE Communications Society, 2013, p. 5541-5546Conference paper (Refereed)
    Abstract [en]

    In this article an experimental evaluation of a broken rotor bar fault detection scheme based on uncertainty bounds violation will be presented. The novelty of this article stems from the establishment and the experimental evaluation of fault detection scheme being able to detect faults at the beginning of its occurrence, based on Set Membership Identification and novel proposed boundary violation rules for the identified motor’s parameters. By the utilization of the SMI technique, the simplified equivalent model of the induction motor is being identified during the steady state operation (non–fault case), while at the same time safety bounds for the identified variables are being provided, based on an a priori defined corrupting additive noise. On the event of a fault, specific fault detection conditions are being proposed that can capture the fault of a broken bar. Detailed analysis of the proposed approach as also extended experimental results are being presented that prove the efficiency of the proposed scheme.

  • 97.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Fault classification scheme for three phase induction motor2014In: International Journal of System Dynamics Applications, ISSN 2160-9772, E-ISSN 2160-9799, Vol. 3, no 1Article in journal (Refereed)
    Abstract [en]

    In this article a fault classification algorithm based on a robust linear discrimination scheme, for the case of a squirrel–cage three phase induction motor, will be presented. The suggested scheme is based on a novel feature extraction mechanism from the measured magnitude and phase of current park’s vector pattern. The proposed methodology has the merit to diagnose different types of faults such as: a) broken rotor bar, and b) short circuit in stator winding. The novel feature generation technique is able to transform the problem of fault detection and diagnosis into a simpler space, where direct robust linear discrimination can be applied for solving the classification problem. Robust linear discrimination has been one of the most widely used fault detection method in real life applications, as this methodology seeks for directions that are efficient for discrimination and at the same time applies a straight forward implementation. The efficacy of the proposed scheme will be evaluated based on multiple simulation results for different fault types.

  • 98.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Fault detection based on set membership identification for three phase induction motors2012Conference paper (Refereed)
    Abstract [en]

    In this article a fault detection scheme for stator winding short circuit fault detection in the case of a three phase induction motor is being presented. The three phase motor is model in (q-d) model space for the normal and the faulty case. The motor is being identified by the utilization of Set Membership Identification (SMI) that has the merit of identifying both the parameters of the motor as also providing uncertainty safety bounds by calculating orthotopes which bounds the system’s parameter vector. Based on the volume and the trend of these orthotopes, rules for identifying the existence of a fault are being presented. If the current values of the identified parameters do not lie inside the safety bounds in the healthy case, but lie in an area that is being defined by the model of the short circuit case, then a fault is being triggered.

  • 99.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Stator winding short circuit fault detection based on set membership identification for three phase induction motors2012In: 2012 20th Mediterranean Conference on Control and Automation: Barcelona, Spain, July 3-6, 2012, Piscataway, NJ: IEEE Communications Society, 2012, p. 290-296Conference paper (Refereed)
    Abstract [en]

    In this article a fault detection scheme for stator winding short circuit fault detection in the case of a three phase induction motor is being presented. The three phase motor is being modeled in the equivalent two phase motor (q−d) space, while the modeling of the faulty case is being also formulated. The motor is being identified by the utilization of Set Membership Identification (SMI) that has the merit of identifying both the parameters of the motor as also providing uncertainty safety bounds by calculating orthotopes which bounds the systems parameter vector. Based on the volume and the trend of these orthotopes, rules for identifying the existence of a fault are being presented. If the current valuesof the identified parameters do not lie inside the safety bounds in the healthy case, but lie in an area that is being defined by the model of the short circuit case, then a fault is being triggered. Detailed analysis of the proposed approach as also extended simulation results are being presented that prove the efficiency of the suggested scheme.

  • 100.
    Mustafa, Mohammed Obaid
    et al.
    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.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Uncertainty Bounds Violation Scheme for Fault Detection in Induction Motors: Application to Broken Rotor Bars2014Conference paper (Other academic)
123 51 - 100 of 134
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