Search results for "VDP::Teknologi: 500::Marin teknologi: 580"
showing 6 items of 6 documents
Design optimisation of a funnel-shaped floating dock for installation of offshore wind turbines
2020
Master's thesis in Civil and structural engineering (BYG508) Offshore wind power is a rapidly growing renewable energy industry and has a tremendous potentialof further expansion. Installation of offshore wind turbines is a challenging task. Floating windturbines are believed to be cost-effective solutions for deep water installation. This technologyis extremely sensitive to wave excitation during the installation process. As deep-water windfarms often are located in areas exposed to rough weather, innovative methods of installation areinvestigated. The floating dock concept has been proposed in recent studies in order to expand theweather window for installing spar floating wind turbines. …
Design and Analysis of a Novel Semi-submersible Floater Supporting a 5MW Wind Turbine
2021
Master's thesis in Civil and structural engineering (BYG508) The wind industry has been rapidly evolving in recent years, moving from onshore to offshorelocations. For deep waters, floating wind turbines are more cost-effective than bottom-fixed ones,and semi-submersible floating wind turbines are especially advantageous compared to other con-cepts because of their relatively small draft and good towability for installation. This masterthesis focuses on preliminary design and analysis of a novel semi-submersible floating wind turbinesupported by a twin fish floater and positioned by a single-point mooring system. Hydrostaticand hydrodynamic analysis are first carried out to select a floater…
Foundations of offshore wind turbines: A review
2019
Abstract Offshore wind is a source of clean, renewable energy of great potential value to the power industry in the context of a low carbon society. Rapid development of offshore wind energy depends on a good understanding of technical issues related to offshore wind turbines, which is spurring ongoing research and development programmes. Foundations of offshore wind turbines present one of the main challenges in offshore wind turbine design. This paper reviews the present state of knowledge concerning geotechnical and structural issues affecting foundation types under consideration for the support structures of offshore wind turbines, and provides recommendations for future research and de…
Robust adaptive backstepping DP control of ROVs
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, operating in environments with unpredictable disturbances, such as an aquaculture net cage. The proposed controller combines the backstepping approach with an adaptation term to ensure robustness. Using Lyapunov theory and Matrosov’s theorem the origin of the closed-loop system is proven to be: (i) globally asymptotically stable when assuming persistency of excitation, and (ii) stable and bounded, with the true position converging to the desired position if there is no pers…
A comparative study on the dynamic response of three semisubmersible floating offshore wind turbines
2019
Abstract Currently, there is a great interest to globally develop offshore wind energy due to the greenhouse effect and energy crisis. Great efforts have been devoted to develop reliable floating offshore wind energy technology to exploit the wind energy resources in deep seas. This paper presents a comparative study of the dynamic response of three different semisubmersible floating wind turbine structures. All the three platforms support the same 5MW wind turbine. The platforms examined are: a V-shaped Semi, an OC4-DeepCwind Semi and a Braceless Semi at 200 m water depth. A dynamic analysis is carried out in order to calculate and compare the performance of these platforms. The comparison…
Automated Plankton Classification With a Dynamic Optimization and Adaptation Cycle
2022
With recent advances in Machine Learning techniques based on Deep Neural Networks (DNNs), automated plankton image classification is becoming increasingly popular within the marine ecological sciences. Yet, while the most advanced methods can achieve human-level performance on the classification of everyday images, plankton image data possess properties that frequently require a final manual validation step. On the one hand, this is due to morphological properties manifesting in high intra-class and low inter-class variability, and, on the other hand is due to spatial-temporal changes in the composition and structure of the plankton community. Composition changes enforce a frequent updating…