Blar i NTNU Open på forfatter "Sørensen, Asgeir Johan"
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Observer design for underwater vehicles with position and angle measurement
Refsnes, Jon E Gorset; Pettersen, Kristin Ytterstad; Sørensen, Asgeir Johan (Journal article, 2006)In this paper we propose a new observer system for underwater vehicles. The main design objective behind this strategy is to reduce the destabilizing effect of the Coriolis and centripetal forces and moments in the observer. ... -
OMAE2017-62498 Real-Time Hybrid Model Testing of a Top Tensioned Riser: a Numerical Case Study on Interface Time-Delays and Truncation Ratio
Sauder, Thomas Michel; Sørensen, Asgeir Johan; Larsen, Kjell (Chapter; Peer reviewed, 2017)This paper investigates the applicability of real-time hybrid model testing (ReaTHM testing) to the study of offshore systems in deep water. The focus is in particular on slender marine structures connecting floating ... -
On Formal Methods for Design and Verification of Maritime Autonomous Surface Ships
Torben, Tobias; Smogeli, Øyvind; Utne, Ingrid Bouwer; Sørensen, Asgeir Johan (Journal article, 2022)Maritime Autonomous Surface Ships (MASS) are approaching a reality, introducing a new level of complexity and criticality to maritime control systems. In this paper we investigate how Formal Methods (FMs) can be used to ... -
Online Consequence Analysis of Situational Awareness for Autonomous Vehicles
Fossdal, Markus (Master thesis, 2018)The maritime industry is undergoing substantial changes with regards to autonomy, and lately important steps has been done in realizing highly autonomous vessels for industry use. This master s thesis presents a framework ... -
Online wave estimation using vessel motion measurements
Brodtkorb, Astrid H.; Nielsen, Ulrik Dam; Sørensen, Asgeir Johan (Journal article; Peer reviewed, 2018)In this paper, a computationally efficient online sea state estimation algorithm is proposed for estimation of the onsite sea state. The algorithm finds the wave spectrum estimate from motion measurements in heave, roll ... -
Optimization-based planning and control of AUVs applied to adaptive sampling under ice
Bremnes, Jens Einar; Devonport, Alex; Yin, He; Arcak, Murat; Sørensen, Asgeir Johan; Utne, Ingrid Bouwer (Chapter, 2020)This paper presents a framework for optimization-based informative planning and control with applications to adaptive sampling with AUVs under sea ice. A spatial model of the information of interest is approximated as a ... -
Path Following Control of Underactuated Surface Vessels in the Presence of Multiple Disturbances
Caharija, Walter; Sørensen, Asgeir Johan; Pettersen, Kristin Ytterstad; Greco, Marilena; Gravdahl, Jan Tommy (Chapter, 2019)An integral version of the line-of-sight guidance method is shown to compensate for both kinematic and dynamic disturbances generated by wind, waves and sea currents. The guidance law is designed for path following tasks ... -
Path generation for high-performance motion of ROVs based on a reference model
Fernandes, Daniel de Almeida; Sørensen, Asgeir Johan; Donha, Decio C (Journal article; Peer reviewed, 2015)This paper deals with the generation of sufficiently smooth position, velocity, and acceleration references for guiding the motion of an ROV along purposefully defined curvature-continuous paths in automated missions. The ... -
Post‐installation adaptation of offshore wind turbine controls
Smilden, Emil; Sørum, Stian Høegh; Bachynski, Erin Elizabeth; Sørensen, Asgeir Johan; Amdahl, Jørgen (Journal article; Peer reviewed, 2020)The cost of offshore wind energy can be reduced by incorporating control strategies to reduce the support structures' load effects into the structural design process. While effective in reducing the cost of support structures, ... -
Preventing Tower Resonance Induced by Thrust Variations on a Large 10MW Wind Turbine
Smilden, Emil (Master thesis, 2015)A simulation model based on a 10MW wind turbine is developed to test the performance of a speed exclusion zone algorithm with the purpose of preventing tower resonance. The model includes rotor aerodynamics, drive-train ... -
Probabilistic robust design of control systems for high-fidelity cyber–physical testing
Sauder, Thomas Michel; Marelli, Stefano; Sørensen, Asgeir Johan (Journal article; Peer reviewed, 2019)Cyber–physical empirical methods consist in partitioning a dynamical system under study into a set of physical and numerical substructures that interact in real-time through a control system. In this paper, we define and ... -
Propulsion methods for under water snake robots - Investigation and simulation using foil for propulsion of a snake robot
Strømsøyen, Simen (Master thesis, 2015)In this thesis we present a model of a swimming underwater snake robot. How aquatic animals move in water has fascinated people for decades. NTNU started the research on land based snake robots 11 years ago. The last years ... -
Real-Time Hybrid Model Testing of Moored Floating Structures Using Nonlinear Finite Element Simulations
Vilsen, Stefan Arenfeldt; Sauder, Thomas Michel; Sørensen, Asgeir Johan (Chapter, 2017)The paper proposes an application of real-time hybrid model testing (abbreviated ReaTHM testing) for the study of moored offshore structures. The structure under study is a moored axisymmetric floater with various bilge ... -
Real-Time Marine Vessel and Power Plant Simulation
Bø, Torstein Ingebrigtsen; Johansen, Tor Arne; Dahl, Andreas Reason; Rejani Miyazaki, Michel; Pedersen, Eilif; Rokseth, Børge; Skjetne, Roger; Sørensen, Asgeir Johan; Thorat, Laxminarayan; Utne, Ingrid Bouwer; Yum, Koosup; Mathiesen, Eirik (Chapter; Peer reviewed, 2015)In this paper, we present a system simulator of a marine vessel and power plant which contains the mechanical system with diesel engines, propellers, steering gear, and thrusters; the electrical system with generators, ... -
Reducing the number of individuals to monitor shoaling fish systems - Application of the Shannon entropy to construct a biological warning system model
Eguiraun, Harkaitz; Casquero, Oskar; Sørensen, Asgeir Johan; Martinez, Iciar (Journal article; Peer reviewed, 2018)The present study aims at identifying the lowest number of fish (European seabass) that could be used for monitoring and/or experimental purposes in small-scale fish facilities by quantifying the effect that the number of ... -
Risk management of autonomous marine systems and operations
Utne, Ingrid Bouwer; Sørensen, Asgeir Johan; Schjølberg, Ingrid (Chapter; Peer reviewed, 2017)Autonomous systems may lead to smarter and more efficient operations, but emerging risks are involved, because of lack of knowledge and operational experience with such systems, and challenges related to verification of ... -
Risk-aware decision-making and control of autonomous ships
Blindheim, Simon Vinding (Doctoral theses at NTNU;2023:200, Doctoral thesis, 2023)Autonomous agents able to operate without human supervision require decision making capabilities that predict outcomes based on internal and external models, sensors and data. However, research on the topic of incorporating ... -
Robust and Reconfigurable On-Board Processing for a Hyperspectral Imaging Small Satellite
Langer, Dennis David; Orlandic, Milica; Bakken, Sivert; Birkeland, Roger; Garrett, Joseph Landon; Johansen, Tor Arne; Sørensen, Asgeir Johan (Peer reviewed; Journal article, 2023)Hyperspectral imaging is a powerful remote sensing technology, but its use in space is limited by the large volume of data it produces, which leads to a downlink bottleneck. Therefore, most payloads to date have been ... -
Robust Dynamic Positioning of offshore vessels using mixed-μ synthesis modeling, design, and practice
Hassani, Vahid; Sørensen, Asgeir Johan; Pascoal, A.M.; Athans, Michael (Journal article, 2017)This paper describes a procedure to design robust controllers for Dynamic Positioning (DP) of ships and offshore rigs subjected to the influence of sea waves, currents, and wind loads using H∞ and mixed-μ techniques. The ... -
ROV Control System for Positioning of Subsea Modules
Henriksen, Eirik Hexeberg (Master thesis, 2014)Installation of deep water Xmas trees for subsea oil production is sometimes done by lowering the tree using one wire. Xmas trees are interfacing with other equip- ment on the seafloor and will therefore need to be positioned, ...