Browsing NTNU Open by Author "Sørensen, Asgeir Johan"
Now showing items 41-60 of 98
-
Hybrid Observer Combining Measurements of Different Fidelities
Brodtkorb, Astrid H.; Teel, Andrew R.; Sørensen, Asgeir Johan (Journal article; Peer reviewed, 2016)A signal-based hybrid observer combining measurements of different fidelities is proposed for position and velocity estimation of marine vessels. The concept assumes that noisy position measurements are available only ... -
Hybrid observer for improved transient performance of a marine vessel in dynamic positioning
Brodtkorb, Astrid H.; Værnø, Svenn Are Tutturen; Teel, Andrew R.; Sørensen, Asgeir Johan; Skjetne, Roger (Journal article; Peer reviewed, 2016)Dynamic positioning (DP) systems are used on marine vessels for automatic station keeping and tracking operations solely by use of thrusters. Observers are key components of DP systems, and two main types are proposed in ... -
Increasing the Operation Window of Dynamic Positioned Vessels Using the Concept of Hybrid Control
Brodtkorb, Astrid Helene; Sørensen, Asgeir Johan; Teel, Andrew R. (Chapter; Peer reviewed, 2014)In order to extend the operational window of marine vessels, the high-level control of the dynamic positioning (DP) system is revised. Major contributions of this paper include the modeling of a hybrid controller for a DP ... -
Integral Line-of-Sight Guidance and Control of Underactuated Marine Vehicles: Theory, Simulations and Experiments
Caharija, Walter; Pettersen, Kristin Ytterstad; Bibuli, Marco; Calado, Pável; Zereik, Enrica; Braga, Jose; Gravdahl, Jan Tommy; Sørensen, Asgeir Johan; Milovanovic, Milan; Bruzzone, Gabriele (Journal article; Peer reviewed, 2016)This paper presents an extensive analysis of the integral line-of-sight (ILOS) guidance method for path-following tasks of underactuated marine vehicles, operating on and below the sea surface. It is shown that due to the ... -
Integrated Environmental Mapping and Monitoring: A methodological approach for end-users
Nilssen, Ingunn (Doctoral theses at NTNU;2016:279, Doctoral thesis, 2016)Summary of thesis The thesis presents a methodological approach for flexible mapping and environmental monitoring that in each case are adjusted to purpose and the present ambient conditions, including anthropogenic ... -
Integration Filter for APS, DVL, IMU and Pressure Gauge for Underwater Vehicles
Dukan, Fredrik; Sørensen, Asgeir Johan (Journal article, 2013)High-accuracy underwater navigation is important in order to automate motion control of remotely operated vehicles (ROVs). An observer that estimates the vehicle states (position, velocity, attitude and turn rates) is ... -
Is ambient light during the high Arctic polar night sufficient to act as a visual cue for zooplankton?
Cohen, Jonathan H.; Berge, Jørgen; Moline, Mark A.; Sørensen, Asgeir Johan; Last, Kim; Falk-Petersen, Stig; Renaud, Paul; Leu, Eva; Grenvald, Julie Cornelius; Cottier, Finlo; Cronin, Heather; Menze, Sebastian; Norgren, Petter; Varpe, Øystein; Daase, Malin; Darnis, Gérald; Johnsen, Geir (Journal article, 2015)The light regime is an ecologically important factor in pelagic habitats, influencing a range of biological processes. However, the availability and importance of light to these processes in high Arctic zooplankton communities ... -
Key Contributors to Lifetime Accumulated Fatigue Damage in an Offshore Wind Turbine Support Structure
Smilden, Emil; Bachynski, Erin Elizabeth; Sørensen, Asgeir Johan (Chapter; Peer reviewed, 2017)A simulation study is performed to identify the key contributors to lifetime accumulated fatigue damage in the support-structure of a 10 MW offshore wind turbine placed on a monopile foundation in 30 m water depth. The ... -
Kombinert modelbasert og sensorbasert observer for undervannsfartøy
Hustveit, Bjarte (Master thesis, 2014)Denne master-oppgaven omhandler arbeidet med å kombinere to ulike typer observere på en slik måte at kombinasjonen av disse to gir et bedre resultat enn det de to observerene klarer hver for seg. De to observerene er den ... -
Mapping the Historical Shipwreck Figaro in the High Arctic Using Underwater Sensor-Carrying Robots
Mogstad, Aksel Alstad; Ødegård, Øyvind; Nornes, Stein Melvær; Ludvigsen, Martin; Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen (Peer reviewed; Journal article, 2020)In 2007, a possible wreck site was discovered in Trygghamna, Isfjorden, Svalbard by the Norwegian Hydrographic Service. Using (1) a REMUS 100 autonomous underwater vehicle (AUV) equipped with a sidescan sonar (SSS) and (2) ... -
Marine Vessel and Power Plant System Simulator
Bø, Torstein Ingebrigtsen; Dahl, Andreas Reason; Johansen, Tor Arne; Mathiesen, Eirik; Rejani Miyazaki, Michel; Pedersen, Eilif; Skjetne, Roger; Sørensen, Asgeir Johan; Thorat, Laxminarayan; Yum, Kevin K. (Peer reviewed, 2015)Modern marine electric propulsion vessels have many systems. These interactions and integration aspects are essential when studying a system and subsystem behavior. This is especially important when considering fault ... -
Method for Real-Time Hybrid Model Testing of ocean structures: Case study on horizontal mooring systems
Vilsen, Stefan Arenfeldt; Sauder, Thomas Michel; Sørensen, Asgeir Johan; Føre, Martin (Journal article; Peer reviewed, 2019)This paper presents a method for Real-Time Hybrid Model testing (ReaTHM testing) of ocean structures. ReaTHM testing is an extension to traditional hydrodynamic model-scale testing, where the system under study is partitioned ... -
Modeling and Control of ROV Manipulator
Haugen, Morten (Master thesis, 2012)The main objective of this thesis is to investigate and present the most relevant techniques and topics within the field of robot modeling and control. The studies will then be used to develop a working control system for ... -
Modeling and Propulsion Methods of Underwater Snake Robots
Kelasidi, Eleni; Pettersen, Kristin Ytterstad; Gravdahl, Jan Tommy; Strømsøyen, Simen; Sørensen, Asgeir Johan (Chapter, 2017)In this paper we consider underwater snake robots (USRs) that may be equipped with additional added effectors along their body, including caudal, dorsal and pectoral fins, tunnel thrusters and/or a stern propeller. We ... -
Modeling of Hydroelastic Response of Closed Flexible Fish Cages due to Sea Loads
Strand, Ida Marlen (Master thesis, 2013)Norway is presently the worlds biggest producer of Atlantic salmon. The traditionally used open-net-structures are probably the most important reason for the Norwegian success.The very nature of aquaculture, where fish is ... -
Modelling and Control of a Two-Body Offshore Wave Energy Converter - Evaluation of Passive Control Strategies
Schultz, Eirik (Master thesis, 2015)The main motivation behind this thesis is using the renewable resource of wave energy to solve two of the most important challenges for sustainability; energy and freshwater. The DynOcean is a two-body offshore wave energy ... -
Modelling and Control of Thruster Assisted Position Mooring System for a Semi-submersible: Analysis and Model Testing
Bjørneset, Solveig (Master thesis, 2014)For harsh weather, nonlinear effects dominate the dynamics to a larger extent than for calm weather. The low frequency dynamics of a moored vessel are excited by second order wave drift forces. To counteract the low-frequency ... -
Modelling and control of underwater inspection vehicle for aquaculture sites
Hval, Mats Nåvik (Master thesis, 2012)Underwater vehicles such as AUVs and ROVs with hovering capabilities is a promising method for inspection of net integrity in large scale, sea based, salmon farms. The location of the salmon farms cause underwater vehicles ... -
Motion Compensation System for a Free Floating Surface Effect Ship
Auestad, Øyvind Fidje; Gravdahl, Jan Tommy; Sørensen, Asgeir Johan; Espeland, Trygve H. (Chapter, 2014)This paper deals with vertical motion compensation, or motion damping, on a freefloating Surface Effect Ship (SES) at zero speed. The Motion Compensation System (MCS) works by varying the air cushion pressure of a Surface ... -
Motion sensing on vessels operating in sea ice: A local monitoring system for transit and stationkeeping operations under the influence of sea ice
Heyn, Hans-Martin (Doctoral theses at NTNU;2019: 138, Doctoral thesis, 2019)The diminishing sea ice in the Arctic and Antarctic could lead to a higher number of ship operations in these areas, such as cargo transit, resource exploration, fishing, and tourism. However, despite the sea ice reduction, ...