Viser treff 21-40 av 46

• #### Efficient Modelling Methodology for Reconfigurable Underwater Robots ﻿

(Journal article; Peer reviewed, 2016)
This paper considers the challenge of applying reconﬁgurable robots in an underwater environment. The main result presented is the development of a model for a system comprised of N, possibly heterogeneous, robots dynamically ...
• #### Exhaust Gas Recirculation Control for Large Diesel Engines - Achievable Performance with SISO Design ﻿

(Journal article; Peer reviewed, 2013)
This paper investigates control possibilities for Exhaust Gas Recirculation (EGR) on large diesel engines. The goal is to reduce the amount of $NO_x$ in the exhaust gas by reducing the oxygen concentration available for ...
• #### Fault diagnosis of downhole drilling incidents using adaptive observers and statistical change detection ﻿

(Journal article; Peer reviewed, 2015)
Downhole abnormal incidents during oil and gas drilling cause costly delays, and may also potentially lead to dangerous scenarios. Different incidents will cause changes to different parts of the physics of the process. ...
• #### Fault Diagnosis of Floating Wind Turbine Drivetrain- Methodologies and Applications ﻿

(Doctoral theses at NTNU;2018:286, Doctoral thesis, 2018)
Increasing demand for renewable energy is driving innovation and attracting many research resources all over the world. Wind energy is one of the most promising sources of renewable energy. Wind turbine has been in use for ...
• #### Fault Monitoring and Fault Recovery Control for Position-Moored Vessels ﻿

(Journal article; Peer reviewed, 2011)
This paper addresses fault-tolerant control for position mooring of a shuttle or floating production storage and offloading vessels. A complete framework for fault diagnosis is presented. A loss of a sub-sea mooring line ...
• #### Fault-tolerant Position-Mooring Control for Offshore Vessels ﻿

(Journal article; Peer reviewed, 2018)
Fault-tolerance is crucial to maintain safety in offshore operations. The objective of this paper is to show how systematic analysis and design of fault-tolerance is conducted for a complex automation system, exemplified ...
• #### Ice condition assessment using onboard accelerometers and statistical change detection ﻿

(Journal article; Peer reviewed, 2019)
The presence of sea ice is the predominant risk for ship operations in the Arctic, and monitoring of ice condition around a vessel is crucial during all times of operation. This paper presents a system for online onboard ...
• #### Incident detection and isolation in drilling using analytical redundancy relations ﻿

(Journal article; Peer reviewed, 2015-08)
Early diagnosis of incidents that could delay or endanger a drilling operation for oil or gas is essential to limit field development costs. Warnings about downhole incidents should come early enough to allow intervention ...
• #### L1 Adaptive Speed Control of a Small Wind Energy Conversion System for Maximum Power Point Tracking ﻿

(Journal article; Peer reviewed, 2014)
This paper presents the design of an L1 adaptive controller for maximum power point tracking (MPPT) of a small variable speed wind energy conversion system (WECS). The proposed controller generates the optimal torque command ...
• #### Modelling and identification for control of gas bearings ﻿

(Journal article; Peer reviewed, 2015)
Gas bearings are popular for their high speed capabilities, low friction and clean operation, but suffer from poor damping, which poses challenges for safe operation in presence of disturbances Feedback control can achieve ...
• #### Modular Underwater Robots: Modeling and Docking Control ﻿

(Doctoral theses at NTNU;2018:167, Doctoral thesis, 2018)
The objective of this thesis is to investigate the modeling and control of modular underwater robots. This objective is motivated by recent events in the offshore industry, where innovative solutions are needed to cope ...
• #### Mooring System Diagnosis and Structural Reliability Control for Position Moored Vessels ﻿

(Journal article; Peer reviewed, 2014)
Early diagnosis and fault-tolerant control are essential for safe operation of floating platforms where mooring systems maintain vessel position and must withstand environmental loads. This paper considers two critical ...
• #### Motion sensing on vessels operating in sea ice: A local monitoring system for transit and stationkeeping operations under the influence of sea ice ﻿

(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, ...
• #### Navigation System Fault Diagnosis for Underwater Vehicle ﻿

(Journal article; Peer reviewed, 2014)
This paper demonstrates fault diagnosis on unmanned underwater vehicles (UUV) based on analysis of structure of the nonlinear dynamics. Residuals are generated using different approaches in structural analysis followed by ...
• #### Nonlinear Adaptive Control of Exhaust Gas Recirculation for Large Diesel Engines ﻿

(Journal article, 2015)
A nonlinear adaptive controller is proposed for the exhaust gas recirculation system on large two-stroke diesel engines. The control design is based on a control oriented model of the nonlinear dynamics at hand that ...
• #### Observer Backstepping Control for Variable Speed Wind Turbine ﻿

(Chapter; Peer reviewed, 2013)
This paper presents an observer backstepping controller as feasible solution to variable speed control of wind turbines to maximize wind power capture when operating between cut-in and rated wind speeds. The wind turbine ...
• #### Parametric Roll Resonance Monitoring using Signal-based Detection ﻿

(Journal article; Peer reviewed, 2015)
Extreme roll motion of ships can be caused by several phenomena, one of which is parametric roll resonance. Several incidents occurred unexpectedly around the millennium and caused vast fiscal losses on large container ...
• #### Particle Filter for Fault Diagnosis and Ropbust Navigation of Underwater Robot ﻿

(Conference object; Journal article; Peer reviewed, 2014)
A particle filter (PF)-based robust navigation with fault diagnosis (FD) is designed for an underwater robot, where 10 failure modes of sensors and thrusters are considered. The nominal underwater robot and its anomaly ...
• #### Performance Comparison of Controllers with Fault-Dependent Control Allocation for UAVs ﻿

(Journal article; Peer reviewed, 2017)
This paper combines fault-dependent control allocation with three different control schemes to obtain fault tolerance in the longitudinal control of unmanned aerial vehicles. The paper shows that fault-dependent control ...
• #### Response analysis and comparison of a spar-type floating offshore wind turbine and an onshore wind turbine under blade pitch controller faults ﻿

(Journal article; Peer reviewed, 2016)
This paper analyses the effects of three pitch controller faults on the responses of an onshore wind turbine and a spar-type offshore floating wind turbine. These faults include: a stuck blade pitch actuator, a fixed value ...