A5000288635- Maritime Navigation and Safety
- Ship Hydrodynamics and Maneuverability
- Robotic Path Planning Algorithms
- Railway Engineering and Dynamics
- Underwater Vehicles and Communication Systems
- Structural Health Monitoring Techniques
- Fault Detection and Control Systems
- Fluid Dynamics Simulations and Interactions
- Target Tracking and Data Fusion in Sensor Networks
- Structural Integrity and Reliability Analysis
- Infrastructure Maintenance and Monitoring
- Tribology and Lubrication Engineering
- Adaptive Control of Nonlinear Systems
- Advanced Memory and Neural Computing
- Railway Systems and Energy Efficiency
- Vibration and Dynamic Analysis
- Wind Energy Research and Development
- Optimization and Search Problems
- Chaos control and synchronization
- Maritime Transport Emissions and Efficiency
- Magnetic Bearings and Levitation Dynamics
- Modular Robots and Swarm Intelligence
- CCD and CMOS Imaging Sensors
- Ferroelectric and Negative Capacitance Devices
- Nonlinear Dynamics and Pattern Formation
Technical University of Denmark
2015-2024
Institute of Automation and Control Processes
2014-2015
University of Copenhagen
2013-2014
Norwegian University of Science and Technology
2011-2012
Ørsted (Denmark)
2007
We present a nonlinear adaptive path following controller that compensates for drift forces through vehicle sideslip. Vehicle sideslip arises during when the is subject to caused by ocean currents, wind, and waves. The proposed algorithm motivated line-of-sight (LOS) guidance principle used ancient navigators, which here extended of Dubins paths. unknown angle treated as constant parameter, estimated using an adaptation law. equilibrium points cross-track parameter estimation errors are...
Abstract Modern computation based on von Neumann architecture is now a mature cutting-edge science. In the architecture, processing and memory units are implemented as separate blocks interchanging data intensively continuously. This transfer responsible for large part of power consumption. The next generation computer technology expected to solve problems at exascale with 10 18 calculations each second. Even though these future computers will be incredibly powerful, if they type...
Parametric roll resonance on ships is a nonlinear phenomenon where waves encountered at twice the natural frequency can bring vessel dynamics into bifurcation mode and lead to extreme values of roll. Recent years have seen several incidents with dramatic damage container vessels. The oscillation, which subharmonic respect wave excitation, may be completely unexpected system for detection onset such could warn navigators before angles reach serious levels. Timely warning make remedial actions...
The paper proposes novel sampling strategies to compute the optimal path alteration of a surface vessel sailing in close quarters. Such strategy directly encodes rules for safe navigation at sea, by exploiting concept minimal ship domain determine compliant region where deviation is be generated. integrated within rapidly-exploring random tree algorithm, which minimizes length deviation. Further, feasibility with respect steering characteristics own verified ensuring that position new...
In this work the initial steps towards a system capable of parametrising fish schools in underwater images are presented. For purpose deep convolutional neural network called Optical Fish Detection Network (OFDNet) is introduced. This based on state-of-the-art learning object detection architectures and carries out task detection, localization species classification using visual data obtained by cameras. focused applications poorly conditioned North Baltic Sea initially developed for...
Parametric roll is a critical phenomenon for ships, whose onset may cause oscillations up to ±40 • , leading very dangerous situations and possibly capsizing.Container ships have been shown be particularly prone parametric resonance when they are sailing in moderate heavy head seas.A Matlab/Simulink benchmark model large container ship has implemented validated against wide set of experimental data.The part Toolbox (MSS, 2007).The implements 3 rd -order nonlinear where the dynamics strongly...
This paper describes an obstacle detection system for a high-speed and agile unmanned surface vehicle (USV), running at speeds up to 30m/s. The aim is real-time high performance using both radar vision technologies detect obstacles within range of 175 m. A computer horizon detector enables highly accurate attitude estimation despite large sudden accelerations. further facilitates the reduction sea clutter by utilising based statistical measure. Full scale trials show significant increase in...
Cyber-resilience is an increasing concern for autonomous navigation of marine vessels. This paper scrutinizes cyber-resilience properties through a prism with three edges: multiple sensor information fusion, diagnosis not-normal behaviours, and change detection. It proposes two-stage estimator mitigation signals used coastal navigation. Developing Likelihood Field approach, the first stage extracts shoreline features from radar matches them to electronic chart. The second associates buoy...
Bycatch in demersal trawl fisheries challenges their sustainability despite the implementation of various gear technical regulations. A step towards extended control over catch process can be established through a real-time monitoring tool that will allow fishers to react unwanted compositions. In this study, for first time commercial fishery sector, we introduce an automated description leverages state-of-the-art region based convolutional neural network (Mask R-CNN) architecture and builds...
The paper presents a path planning algorithm based on RRT⁎ that addresses the risk of grounding during evasive manoeuvres to avoid collision. planner achieves this objective by integrating collective navigation experience with systematic use water depth information from electronic navigational chart. Multivariate kernel density estimation is applied historical AIS data generate probabilistic model describing seafarer's best practices while sailing in confined waters. This knowledge then...
Accurate position measurements are extremely valuable in the shipping industry for various reasons such as safety (collision avoidance), security (situational awareness), fuel-saving (weather identification), punctuality (route prediction), etc. Although GNSS (Global Navigation Satellite System) receivers installed on-board ships proven to be highly accurate, data logging process may occasionally problematic, mainly due complexity of and decimal precision that is required. Data were...
This paper investigates self-reconfiguration of a modular robotic system, which consists cluster vehicles that can attach to each other by connection mechanism. Thereby, they form desired morphology meet task specific requirements. Reconfiguration be needed due limitations from dimensions passable corridors for an underwater maintenance task, supplemental instrumentation is available on particular robot, or as remedial action if one robot in suffers malfunction. Being crucial autonomous...
Collisions and groundings account for a great deal of fiscal losses human risks in the statistics marine accidents related to ocean going vessels. With highly automated vessels offering high degree situational awareness, algorithms can anticipate developments suggest timely actions avoid or deconflict critical events, accordance safe navigational practices compliance with Convention on International Regulations Preventing at Sea (COLREGs). To such navigation, this article proposes Short...
Parametric ship roll resonance is a phenomenon where can rapidly develop high motion while sailing in longitudinal waves. This effect be described mathematically by periodic changes of the parameters equations motion, which lead to bifurcation. In this paper, control design an active u-tank stabilizer carried out using Lyapunov theory. A nonlinear backstepping controller developed provide global exponential stability roll. An extension commonly used models presented account for large angles,...
The paper continues a study on the wave buoy analogy that uses shipboard measurements to estimate sea states. In present study, is formulated directly in time domain and relies only partly wave-vessel response amplitude operators (RAOs), which contrast all previous works either are frequency and/or depend entirely RAOs. Specifically, evaluates novel concept for estimation based combined techniques using estimator, not dependent RAOs, detect and, respectively, nonlinear least squares fitting...
The wave buoy analogy is a tested means for shipboard sea state estimation. Basically, the estimation principle resembles that of traditional rider which relies, fundamentally, on transfer functions used to relate measured wave-induced responses and unknown excitation. This paper addresses however newly developed concept but approach presented herein is, contrary, not relying exclusively functions. Instead, method combines signal-based part, estimating frequency, model-based amplitude phase,...
Parametric roll resonance on a ship is condition where large motion develops rapidly in moderate head or following seas. The phenomenon caused by bifurcation the nonlinear equations of when restoring moment subject to periodic variation. This paper analyzes stability system and suggests active control both speed fin stabilizers stabilise condition. Lyapunov backstepping designs are employed achieve two controllers, which proved system. designed controllers validated employing high fidelity...
This paper presents an observer backstepping controller as feasible solution to variable speed control of wind turbines maximize power capture when operating between cut-in and rated speeds. The turbine is modeled a two-mass drive-train system controlled by the generator torque. nonlinear aims at regulating torque such that optimal tip-speed ratio can be obtained. Simply relying on measured rotor angular velocity proposed guarantees global asymptotic tracking desired trajectory while...