Now showing items 1-20 of 50

    • Adaptive Backstepping Control for a Fully-Actuated Rigid-Body in a Dual-Quaternion Framework 

      Andersen, Tom Stian; Kristiansen, Raymond (Chapter; Bokkapittel, 2020-03-12)
      We address the trajectory tracking problem for a fully actuated rigid-body with unknown mass and inertia parameters and unknown disturbance forces, using an adaptive backstepping controller based on dual-quaternions. We show that the proposed controller, in closed loop with a nonlinear model of the system, renders the equilibrium points uniformly asymptotically stable. The proposed controller ...
    • Advanced Model Predictive Control Algorithm for Inverters as a Low-cost Solution in ZynQ 

      Hoff, Bjarte (Conference object; Konferansebidrag, 2016)
    • 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 ...
    • Approaches to learning of linear algebra among engineering students 

      Rensaa, Ragnhild Johanne (Peer reviewed; Bok; Book; Bokkapittel; 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 ...
    • Attitude Determination and Control System for Satellites in Elliptical Orbits - a Complete Solution 

      Oland, Espen (Peer reviewed; Conference object; Konferansebidrag; Bokkapittel; Chapter, 2017-08-08)
      This paper presents a complete solution to the problem of attitude determination and control for satellites in elliptical orbits. Specifically, it shows how to create the orbital mechanics, account for perturbing gravity torques, create a nonlinear PD+ attitude controller, map the control signal to desired thrust firings, implement magnetic field and Sun vector models, and how to implement a Madgwick ...
    • Autonomous Inspection of the International Space Station 

      Oland, Espen (Peer reviewed; Bokkapittel; Conference object; Konferansebidrag; Chapter, 2017-09-18)
      This paper presents a solution to autonomous inspection of the international space station using a rigid spacecraft. Specifically, the paper presents the orbital mechanics, formation dynamics as well as rotational dynamics required to control the spacecraft relative to the space station, and then presents two PD+ controllers enabling a spacecraft to track a series of waypoints while pointing a sensor ...
    • 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)
    • Cascaded Model Predictive Control of Grid Connected Converter with LCL Filter 

      Hoff, Bjarte (Peer reviewed; Book; Chapter, 2018-12-31)
      This paper presents a control strategy for grid connected voltage source converters with LCL filter, based on a cascade of two model predictive controllers (MPC). Despite the attention MPC has received in the research community over the last years, there are still raised question about what advantages such control methods can offer, compared to existing established control strategies. The cascaded ...
    • Charging technology for small maritime vessels 

      Hoff, Bjarte (Conference object, 2019-01-21)
    • A Comparative Study of Different Control Structures for Flight Control with New Results 

      Oland, Espen; Kristiansen, Raymond; Gravdahl, Jan Tommy (Peer reviewed; Book; Chapter, 2018-10-24)
      This paper presents several different control structures that facilitate flight control and does a comparison between them. Specifically, this paper considers command-filtered backstepping, nonlinear dynamic inversion (NDI), and a new decoupled approach that decouples the rotational and translational dynamics by estimating the higher order derivatives of the angle of attack and sideslip angle. The ...
    • Controlling a Chain of Integrators with Constrained Actuation Using Exponential Activation Functions 

      Oland, Espen; Kristiansen, Raymond (Peer reviewed; Chapter; Bokkapittel, 2019-10-24)
      This paper shows how to control a chain of integrators with constrained actuation by using exponential activation functions. Specifically, it shows how the control law can be decomposed into several parts that can be activated as they are required, resulting in a simple control law that is able to make the states converge fast to zero.
    • Coordinated Power Management and Control of Standalone PV-Hybrid System with Modified IWO-Based MPPT 

      Pradhan, Chittaranjan; Senapati, Manoj Kumar; Malla, Siva Ganesh; Nayak, Paresh Kumar; Gjengedal, Terje (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-14)
      To augment the photovoltaic (PV) power generation conversion, a maximum power point tracking (MPPT) technique plays a very significant role. This article introduces a hybrid MPPT algorithm integrating modified invasive weed optimization (MIWO) and perturb and observe (P&O) technique under the rapid weather change and partial shading scenarios for the efficient extraction of the maximum power from ...
    • Curvature Continuous Path Generation for UAVs based on Generalized Expo-Rational B-Splines 

      Andersen, Tom Stian; Bouzidi, Ghada; Kristiansen, Raymond (Peer reviewed; Book; Chapter, 2018)
      This paper proposes a new path-planning algorithm based on GERBS to generate curvature continuous paths. The algorithm blends between a set of local curves generating a global smooth path which also interpolates the midpoint of the curves. Numerical examples are provided which demonstrates the potential of the proposed algorithm.
    • 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 ...
    • Digitalization of the power business: How to make this work? 

      Svendsen, Arne Brufladt; Tollefsen, Trond; Gjengedal, Terje; Goodwin, Morten; Antonsen, Stian (Peer reviewed; Bokkapittel; Book; Bok; Chapter, 2018)
      As a result of the digitalization of the power business in Norway and Europa, a lot of new possibilities and challenges arise. In 2014 an expert committee one outlined a proposal for the future grid company structure in Norway (Reiten, 2014). In addition, new technologies are being implemented in the system. Wind power, solar power, un-regulated small hydro power production, battery storage domestic ...
    • Dual quaternion control: a review of recent results within motion control 

      Johansen, Tor-Aleksander; Sánchez, José J.; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-24)
      This paper presents a review of recent results in the field of dual quaternion based motion control. In addition, we derive two control laws for trajectory tracking control of a fully actuated rigid-body based on the resemblance of dual quaternion kinematics and dynamics to the quaternion based rotational kinematics and dynamics. A velocity error sliding surface and an integrator backstepping ...
    • Dual-quaternion backstepping control for a fully-actuated rigid-body 

      Andersen, Tom Stian; Johansen, Tor-Aleksander; Kristiansen, Raymond (Peer reviewed; Book; Chapter, 2018-08-16)
      In this paper dual-quaternions are used to model a fully actuated rigid-body. A backstepping-controller that solves the trajectory tracking problem is derived and proved to provide uniform asymptotical stabilization of the error dynamics. Numerical simulations are provided where the controller is compared to existing dual-quaternion tracking controllers and it is shown to have similar performance.
    • Electric Ships in Norway - Experiences and Future trends. 

      Hoff, Bjarte (Conference object; Konferansebidrag, 2020)
    • Engineering students' instrumental approaches to mathematics; some positive characteristics 

      Rensaa, Ragnhild Johanne (Journal article; Peer reviewed, 2018)
      The present paper presents three deliberately chosen mathematical episodes observed in a class of engineering students taking a basic calculus course. By drawing on analyses of instrumental and relational learning strategies, the episodes are shown to illustrate instrumental approaches indicated by the students. The paper discusses positive characteristics about these approaches while further data ...
    • 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 ...