Browsing NTNU Open by Author "Ohrem, Sveinung Johan"
Now showing items 1-20 of 22
-
A Comparison of Hazards and Efficiencies of Conventional and Adaptive Control Algorithms Using Systems-Theoretic Process Analysis
Ohrem, Sveinung Johan; Kim, Hyungju; Lundteigen, Mary Ann; Holden, Christian (Journal article; Peer reviewed, 2019)Control systems are an important and increasingly complex part of most industrial and non-industrial systems. As such, identifying and handling associated risks is increasingly important. Systems- Theoretic Process Analysis ... -
Adaptive Control of Subsea Processes
Ohrem, Sveinung Johan (Doctoral theses at NTNU;2019:217, Doctoral thesis, 2019) -
Adaptive controller and observer design using open and closed-loop reference models for linear time-invariant systems with unknown dynamics
Ohrem, Sveinung Johan; Holden, Christian (Peer reviewed; Journal article, 2021)This article presents an output feedback controller and observer design approach for linear time-invariant systems with unknown dynamics. The presented method uses an open-loop reference model to generate the desired ... -
Adaptive Feedback Linearizing Control of a Gas Liquid Cylindrical Cyclone
Ohrem, Sveinung Johan; Kristoffersen, Torstein Thode; Holden, Christian (Chapter, 2017)As subsea production of oil and gas reaches deeper and more remote waters, the need for more compact separation equipment arises. The gas hquid cylindrical cyclone (GLCC) is a widely used separation device in topside ... -
Adaptive Generalized Super-Twisting Tracking Control of an Underwater Vehicle
Haugaløkken, Bent Oddvar Arnesen; Amundsen, Herman Biørn; Fadum, Håkon Syverud; Gravdahl, Jan Tommy; Ohrem, Sveinung Johan (Chapter, 2023)Tracking control for unmanned underwater vehicles is essential, both for autonomous operations and complex tasks where the vehicle is manually controlled by a pilot. Underwater vehicles are typically subjected to perturbations ... -
Adaptive motion planning and path following for permanent resident biofouling prevention robot operating in fish farms
Føre, Martin; Fjæra, Sverre; Ohrem, Sveinung Johan; Kelasidi, Eleni; Bloecher, Nina; Amundsen, Herman Biørn (Journal article, 2022)This paper presents a study where the potential of achieving autonomous net cleaning operations in commercial net pens is demonstrated through numerical simulations. Specifically, we investigated solutions for coping with ... -
Adaptive Speed Control of ROVs with Experimental Results from an Aquaculture Net Pen Inspection Operation
Ohrem, Sveinung Johan; Evjemo, Linn Danielsen; Haugaløkken, Bent Oddvar Arnesen; Amundsen, Herman Biørn; Kelasidi, Eleni (Peer reviewed; Journal article, 2023)Remotely operated vehicles (ROVs) are often used for inspection in aquaculture net pens which serves the important purpose of localizing holes in the net and reporting potential irregularities and damages. Manual control ... -
Application of modified Model Reference Adaptive Controller and Observer (MRACO) for speed control of an unmanned underwater vehicle
Ohrem, Sveinung Johan; Haugaløkken, Bent Oddvar Arnesen; Holden, Christian (Peer reviewed; Journal article, 2024) -
Control Strategies for Autonomous Net Cleaning Operations using Underwater Robotic System
Seehuus, Håvard Løvseth (Master thesis, 2020)Motivert av utfordringer innen havbruksnæringen kunnet til uønsket begroing vil denne oppgave fokusere på løsninger innen robotikk for håndtering av begroing. Ved å finne nye løsninger for å hindre store ansamlinger av ... -
Controller and observer design for first order LTI systems with unknown dynamics
Ohrem, Sveinung Johan; Holden, Christian (Chapter, 2018)The design of controllers and observers often relies on first order models of the system in question. These models are often obtained either through step-response tests, through on-line or off-line identification, or through ... -
Controller Design and Control Structure Analysis for a Novel Oil–Water Multi-Pipe Separator
Ohrem, Sveinung Johan; Skjefstad, Håvard Slettahjell; Stanko, Milan; Holden, Christian (Journal article; Peer reviewed, 2019)To enable more efficient production of hydrocarbons on the seabed in waters where traditional separator equipment is infeasible, the offshore oil and gas industry is leaning towards more compact separation equipment. A ... -
Design of Compact Separator Laboratory
Ellefsen, Andre Listou; Aasen, Emil Yde (Master thesis, 2016)Most of the easily accessible offshore oil and gas resources have been developed. As a result of this, subsea production and processing has over the last decade been regarded as the future of the offshore oil and gas ... -
Development of a Dynamic Positioning System for Merlin WR 200 ROV - Development and implementation of a model based control law for station keeping and path following
Ohrem, Sveinung Johan (Master thesis, 2015)Control of Remotely Operated Vehicles (ROVs) with manipulator arms require control of all degrees of freedom. In particular, it is necessary to be able to keep the vehicle at a constant position and orientation in order ... -
Digital Twins in intensive aquaculture — Challenges, opportunities and future prospects
Føre, Martin; Alver, Morten Omholt; Alfredsen, Jo Arve; Rasheed, Adil; Hukkelås, Thor; Bjelland, Hans Vanhauwaert; Su, Biao; Ohrem, Sveinung Johan; Kelasidi, Eleni; Norton, Tomas; Papandroulakis, Nikos (Peer reviewed; Journal article, 2024)Digital Twin technology has emerged to become a key enabling technology in the ongoing transition into Industry 4.0. A Digital Twin is in essence a digital representation of an asset that provides better insight into its ... -
L1 Adaptive Anti-Slug Control
Ohrem, Sveinung Johan; Holden, Christian; Jahanshahi, Esmaeil; Skogestad, Sigurd (Journal article; Peer reviewed, 2017)In many multiphase pipeline-riser systems, anti-slug control is necessary to ensure steady and optimal operation. In this paper, we propose using an ℒ1 adaptive controller as an augmentation to standard PI control to ... -
Model-Based and Model-Free Optimal Control of a Gas Liquid Cylindrical Cyclone
Ohrem, Sveinung Johan; Kristoffersen, Torstein Thode; Holden, Christian (Journal article; Peer reviewed, 2018)Optimal control is important in the oil and gas industry, where small changes of process variables may have significant economical, environmental and safety impacts. Finding the optimal setpoint for a controlled variable ... -
Modeling and nonlinear model predictive control of a subsea pump station
Ohrem, Sveinung Johan; Holden, Christian (Journal article; Peer reviewed, 2017)In this paper we present a model of a pump station consisting of two pumps in parallel with a recycle line, and a nonlinear Model Predictive Control strategy for said pump station with suction pressure as the controlled ... -
Optimal and Adaptive Path Planning and Following for Permanent Resident Cleaning Robot Operating in Fish Farms
Fjæra, Sverre (Master thesis, 2021)Denne oppgåva presenterar resultata frå matematiske simuleringar av ein autonom undervanns notvaskarrobot som skal brukast i eit havbruksmiljø for å forhindra ei av hovedutfordringane i oppdrettsnæringa; biobegroing på ... -
Robust adaptive backstepping DP control of ROVs
Ohrem, Sveinung Johan; Amundsen, Herman Biørn; Caharija, Walter; Holden, Christian (Peer reviewed; Journal article, 2022)Dynamic positioning is an important control feature for an underwater remotely operated vehicle. This paper presents a nonlinear dynamic positioning controller suited for application to vehicles with model uncertainties, ... -
The Generalized Super-Twisting Algorithm Used for Robust Control of Unmanned Subsea Vehicles Operating at Exposed Aquaculture Sites
Fadum, Håkon Syverud (Master thesis, 2022)Fiskeoppdrett er en industri i stor vekst. Den norske fiskeoppdrettsindustrien ønsker å utnytte eksponerte havbrukslokasjoner for fiskeoppdrett. Dette er på grunn av forskjellige miljø og plassproblemer som industrien ...