Now showing items 1-10 of 22
Approaches to learning of linear algebra among engineering students
(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 ...
Autonomous Inspection of the International Space Station
(Peer reviewed; Konferansebidrag; Bokkapittel; Conference object; 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 ...
Attitude Determination and Control System for Satellites in Elliptical Orbits - a Complete Solution
(Peer reviewed; Bokkapittel; Konferansebidrag; Conference object; 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 ...
Quaternion guidance and control of quadrotor
(Peer reviewed; Konferansebidrag; Bokkapittel; Conference object; Chapter, 2017-07-27)
This paper addresses the problem of trajectory tracking for underactuated quadrotors. A quaternion based guidance law is proposed which feeds into an attitude control system based on a PD+ control law. The desired attitude from the guidance law is defined such that the attitude control system tries to align the position error along the axis of the translational actuator. Simulation results are ...
Path-following in three dimensions using quaternions for a fixed-wing UAV
(Peer reviewed; Konferansebidrag; Bokkapittel; Conference object; Chapter, 2017-08-08)
This paper presents a three dimensional guidance strategy for fixed-wing UAVs using quaternions. The algorithm is based on constructing two quaternions, one which makes the UAV fly towards the path and one that makes the UAV follow the path. These two quaternions are then blended together such that the path-following objective is reached. The guidance algorithm is applied to a simple kinematic model ...
Thyristor based short circuit current injection in isolated grids
(Peer reviewed; Bokkapittel; Chapter, 2017-02-16)
This paper proposes a thyristor based short circuit current injector for providing short circuit current in isolated and weak grids, where sufficient fault current to trigger circuit breakers may not be available. This will allow the use of conventional miniature circuit breakers, which requires high fault current for instantaneous tripping. The method has been validated through experiments.
A Reliable Modular Based PV-Battery Hybrid System with Peak Shaving Capability
(Peer reviewed; Chapter, 2018)
The driving factors in emerging photovoltaic (PV) systems and battery-energy-storage systems (BESS) are highly scalable feature, modular and flexible structures with superior transformerless performance. The feasibility of Modular Multilevel Converter (MMC) to operate without overall DC-link allows the integration of PV generators and battery strings with its submodules (SMs), whereas each SM acts ...
Digitalization of the power business: How to make this work?
(Peer reviewed; Bok; Book; Bokkapittel; 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 ...
Controlling a Chain of Integrators with Constrained Actuation Using Exponential Activation Functions
(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.
Framework for Modeling and Simulation of Household Appliances
(Peer reviewed; Book; Chapter, 2018-12-31)
This paper describes a framework for simulating household appliances in Simulink. Typical Norwegian household equipment have been analyzed based on their characteristic behavior, to establish the requirement for synthesizing and recreating their current waveform, harmonic currents and phase shift. Both detailed simulation of the current waveform and RMS currents for simulation over longer time periods ...