• 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 ...
    • Application of Dual Quaternions to the problem of trajectory tracking with quadrotor-gimbal platform 

      Johansen, Tor-Aleksander; Kristiansen, Raymond (Chapter; Bokkapittel, 2022)
      We address the problem of state feedback trajectory tracking of the composite quadrotor-gimbal platform using the dual quaternion framework by extending the previuous result in [1] to the composite case. More precisely; we model the composite system using dual quaternion coordinates and derive the error dynamics which by inserting a PD + based control law has equilibrium points that is shown to be ...
    • 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 ...
    • 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 ...
    • 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.
    • 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 ...
    • 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.
    • Modelling and simulation of interaction forces in tugboat-assisted docking of large marine vessels 

      Kristiansen, Raymond; Ørke, Henning; Gravdahl, Jan Tommy (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-22)
      In this paper, we address modelling and simulation of dynamics involved in docking of large marine vessels with aid of tugboats, with the aim of providing a tool for improved design of control algorithms for autonomous docking operations. Mathematical models of the docking vessel and tugboats in 3DOF are derived, with a special focus on realistic interactions through towline, contact and friction ...
    • Multi-source data collection for state-of-the-art data analysis from ground-proximate images in sea ice classification 

      Woltmann, Lucas; Dalmo, Rune; Kristiansen, Raymond (Konferansebidrag; Conference object, 2017-08-08)
      In modern data analysis it is imperative to use well maintained data sources with curated content. This publication gives an approach for research areas, where there is no such central facility. The specific area used here is sea ice classification from images. The publication is split into two parts. The first part describes the integration of discontinuous sources for different aspects of data ...
    • Path planning and reactive based control for a quadrotor with a suspended load 

      Corona Sanchez, Jose Juan; Kristiansen, Raymond; Andersen, Tom Stian (Conference object; Konferansebidrag, 2021-06)
      This paper presents a solution to quadrotor cargo transportation, more precisely when cargo is suspended as a sling load. The challenge lies in payload position control and swing attenuation, which we approach by dividing the model into subsystems: attitude quadrotor in free flight, and translational and attitude load dynamics. We propose a solution based on reactive control, in the sense that we ...
    • Path-following in three dimensions using quaternions for a fixed-wing UAV 

      Andersen, Tom Stian; Kristiansen, Raymond (Conference object; Konferansebidrag, 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 ...
    • PD+ based trajectory tracking of the underactuated quadrotor platform using dual quaternions 

      Johansen, Tor-Aleksander; Andersen, Tom Stian; Kristiansen, Raymond (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-29)
      We address the problem of state feedback trajectory tracking of the underactuated quadrotor platform in the dual quaternion framework through a PD+ tracking controller. The control law negates the need of generating a desired attitude trajectory as the translational error is mapped directly onto the rotational actuators through a virtual frame. More precisely, we show uniform practical asymptotic ...
    • Quadrotor attitude estimation using adaptive fading multiplicative EKF 

      Johansen, Tor-Aleksander; Kristiansen, Raymond (Konferansebidrag; Conference object, 2017-07-03)
      This paper presents the implementation of an adaptive fading multiplicative extended Kalman filter (AFMEKF), applied to the problem of attitude estimation in the context of quadrotors. The extended Kalman filter is adapted for use with quaternions and made adaptive to account for inaccurate measurement information. Simulations have been conducted in order to validate the filter performance.
    • Quaternion guidance and control of quadrotor 

      Andersen, Tom Stian; Kristiansen, Raymond (Konferansebidrag; Conference object, 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 ...
    • Quaternion Path-Following in Three Dimensions for a Fixed-Wing UAV Using Quaternion Blending 

      Andersen, Tom Stian; Kristiansen, Raymond (Peer reviewed; Book; Chapter, 2018-10-29)
      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 ...
    • Reactive-Based Position Control of an Underactuated Quadrotor 

      Andersen, Tom Stian; Kristiansen, Raymond (Chapter; Bokkapittel, 2020-07-20)
      This paper addresses the problem of position control or waypoint tracking for an underactuated quadrotor. The proposed control law is what is known as reaction based in the way that the attitude system reacts to errors in the translational motion. This methodology requires no generation of desired attitude or angular velocity and the resulting control law is model-independent in that it does ...
    • Real-Time Particle Tracking using a Formation of UAVs 

      Oland, Espen; Kristiansen, Raymond (Journal article; Peer reviewed; Tidsskriftartikkel, 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 ...
    • Stabilization of Non-Cooperative Satellites in Low Earth Orbits using Inter-Satellite Atmospheric Drag 

      Oland, Espen; Kristiansen, Raymond (Chapter; Bokkapittel, 2023-08-07)
      This paper presents a novel solution to the problem of stabilization of non-cooperative satellites in low Earth orbits, which utilizes inter-satellite aerodynamic drag effects for generation of aerodynamics moments in the wake of a controlled satellite. Hence, by altering the position of a smaller controlled satellite, we are able to change the wake region and thus provide aerodynamic moments for ...