• Cascade-Based Controlled Attitude Synchronization and Tracking of Spacecraft in Leader-Follower Formation 

      Schlanbusch, Rune; Nicklasson, Per Johan; Loria, Antonio (Journal article; Peer reviewed; Tidsskriftartikkel, 2011)
    • Ant colony optimization and analysis of time step resolution in transmission expansion computations for wind power integration 

      Fuchs, Ida; Gjengedal, Terje (Chapter; Bokkapittel, 2011)
      This paper investigates the necessary time step resolution in a transmission expansion planning algorithm based on ant colony optimization. A maximal and efficient wind power integration is the main motivation for the grid expansion, which requires a planning tool dealing with wind energy fluctuations. For the analysis a power system model for the Nordic area is used, including a wind power ...
    • Underactuated Waypoint Tracking of a Fixed-Wing UAV 

      Oland, Espen; Schlanbusch, Rune; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      In this paper a new method of performing waypoint tracking is shown for underactuated fixed-wing UAVs. The position error can be mapped onto the desired axis using a desired rotation matrix, while the velocity error can be mapped to the desired axis using a desired angular velocity. With all errors defined along one axis, the tracking problem is easily solved using only one thruster. A velocity ...
    • Underactuated Control of Quadrotors with Collision Avoidance 

      Oland, Espen; Andersen, Tom Stian; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      In this paper a saturated controller is derived that solves the translational control problem for underactuated quadrotors. The controller is applied to multiple quadrotors during a formation reconfiguration where the quadrotors move from an initial position to a desired position. The null-space-based behavioral control method is a popular method for avoiding collisions between mobile agents, and ...
    • Real-Time Particle Tracking using a Formation of UAVs 

      Oland, Espen; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      In this paper the problem of real-time particle tracking is studied. Using sensor measurements, a formation of UAVs autonomously find the closest point with high particle density where they enter a holding pattern. After converging to the holding pattern, one UAV will remain, while the rest will go looking for other maxima. To avoid collisions between the UAVs during the mission, a controller is ...
    • Ubemannede flaksende mikrofly 

      Oland, Espen (Journal article; Tidsskriftartikkel, 2013)
    • Control of Spacecraft Formation with Disturbance Rejection and Exponential Gains 

      Schlanbusch, Rune; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      We address the problem of state feedback translational motion control of a spacecraft formation through a modified sliding surface controller using variable gains and I^2 action for disturbance rejection. The exponential varying gains ensure faster convergence of the state trajectories during attitude maneuver while keeping the gains small (and the system less stiff) for station keeping. Integral ...
    • Experimental study of relative permittivity of atmospheric ice 

      Bhattu, Shravan K; Mughal, Umair Najeeb; Virk, Muhammad Shakeel (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-01-01)
      Atmospheric icing on onshore and offshore structures is problematic, if we don’t detect and remove it. Despite of various ice detection techniques, capacitor based ice sensing technique is interesting one, as it is based on dielectric properties of material. This technique of measuring icing event is simple and cost- effective. Based on the dielectric concept, an experi mental ...
    • Optical water types of the Nordic Seas and adjacent areas 

      Aas, Eyvind; Højerslev, Niels Kristian; Høkedal, Jo; Sørensen, Kai (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-05-20)
      A new map of Jerlov's optical water types in the Nordic Seas and adjacent waters at 139 locations, as well as a table with statistical and geographical properties of the vertical attenuation coefficient of downward irradiance at 475 nm, are presented. The data analysis is based on 715 recordings at different stations, at latitudes between 54° and 82°N, and longitudes between 31°W and 49°E, obtained ...
    • Estimation of upward radiances and reflectances at the surface of the sea from above-surface measurements 

      Kleiv, Øyvind; Folkestad, Are; Høkedal, Jo; Aas, Eyvind; Sørensen, Kai (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-02)
      During 4 field days in the years 2009–2011, 22 data sets of measurements were collected in the inner Oslofjord, Norway. The data consist of recordings of spectral nadir radiances in air and water as well as spectral downward irradiance in air. The studied wavelengths are 351, 400, 413, 443, 490, 510, 560, 620, 665, 681, 709 and 754 nm. The water-leaving radiance and the reflected radiance at the ...
    • A note about frequencies being close or amplitudes being small in frequency analysis 

      Rensaa, Ragnhild Johanne (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-10)
      In an earlier paper, an alternative method for how to solve the frequency analysis problem was offered. The object of the present paper is to bring about how to handle situations where the frequencies are close to each other or there is an amplitude that is really small.
    • Ingeniørstudenters bruk av læringsverktøy i et lineær algebraemne : hvilken rolle spiller nettbaserte forelesninger? 

      Rensaa, Ragnhild Johanne (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-11)
      I denne artikkelen diskuteres studentenes bruk av læringsverktøy med spesielt fokus på et nettbasert tilbud. Egne forelesninger i et emne i lineær algebra for master ingeniørstudenter, fjerde år, har blitt streamet og publisert, og jeg har undersøkt hvordan studentene har brukt disse forelesningene. Data er innsamlet første og tredje gang dette ble gjort, og hovedvekten i denne artikkelen er lagt ...
    • Advanced Model Predictive Control Algorithm for Inverters as a Low-cost Solution in ZynQ 

      Hoff, Bjarte (Conference object; Konferansebidrag, 2016)
    • Smarte nett - Framtidas fleksible energisystem 

      Hoff, Bjarte (Conference object; Konferansebidrag, 2016)
    • A Decoupled Approach for Flight Control 

      Oland, Espen; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      A decoupling method for flight control is presented that greatly simplifies the controller design. By approximating the higher order derivatives of the angle of attack and sideslip, it enables a rotation controller and a speed controller to be derived independently of each other, and thus gives access to a vast number of controller solutions derived for general classes of rotational and translational ...
    • Smarte nett - Framtidas fleksible energisystem 

      Hoff, Bjarte (Konferansebidrag; Conference object, 2016-03-16)
    • Subsumption architecture applied to flight control using composite rotations 

      Oland, Espen; Andersen, Tom Stian; Kristiansen, Raymond (Peer reviewed; Tidsskriftartikkel; Journal article, 2016-03-19)
      In this paper the subsumption theory is applied to flight control through composite rotations where multiple tasks can be defined as simple rotations. The tasks can then be arranged as a hierarchy, where the primary task is always fully pursued, and conflicting lower level tasks are removed by the primary rotation. The concept is applied to a group of uavs that move through an urban terrain while ...
    • Smart grid solutions for integration of renewable energy in remote communities 

      Hoff, Bjarte (Conference object; Konferansebidrag, 2017)
    • Smarte løsninger for integrering av fornybar energi 

      Hoff, Bjarte (Konferansebidrag; Conference object, 2017)
    • Approaches to learning of linear algebra among engineering students 

      Rensaa, Ragnhild Johanne (Peer reviewed; Bok; Bokkapittel; Book; Chapter, 2017-02)
      The present paper investigates engineering students` own descriptions of what they mean by learning of linear algebra and how they know that they have learned something. I seek to extract keywords from engineering students` descriptions of learning of this discipline by drawing on grounded theory techniques and classifying the answers in conceptual and procedural approaches. By this, both detailed ...