Blar i NTNU Open på forfatter "Dirdal, Johann Alexander"
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A Methodology for Tuning of Computational Vessel Models Utilizing Wave Measurements From X-Band Marine Radar and Wave Buoy
Radhakrishnan, Gowtham; Leira, Bernt Johan; Gao, Zhen; Sævik, Svein; Kaasen, Karl Erik; Christakos, Konstantinos; Dirdal, Johann Alexander (Chapter, 2023)Accurate estimation of the wave field and subsequent vessel response prediction are vital for making crucial judgments on the safe and timely execution of marine operations. Decision support systems based on the Response-Based ... -
Nonlinear Autonomous Docking and Path-Following Control Systems for the Otter USV
Torvund, Per Gunnar Berg (Master thesis, 2020)Denne oppgaven gikk ut på å bruke ulineære kontrollalgoritmer for autonom dokking, banefølging og hinderunngåelse for Maritime Robotics sin minste overflatefarkost, "Oteren". Autonom dokking er for tiden et hett tema der ... -
Online wave direction and wave number estimation from surface vessel motions using distributed inertial measurement arrays and phase-time-path-differences
Dirdal, Johann Alexander; Skjetne, Roger; Roháč, Jan; Fossen, Thor I. (Peer reviewed; Journal article, 2022)A common approach for finding the direction of ocean waves is to use the phase-time-path-differences (PTPDs) between a static array of various types of sensors mounted on either the sea surface or seabed. However, some ... -
A phase-time-path-difference approach for online wave direction and wave number estimation from measured ship motions in zero and forward speed using a single inertial measurement unit
Dirdal, Johann Alexander; Skjetne, Roger; Roháč, Jan; Fossen, Thor I. (Journal article; Peer reviewed, 2023)This study investigates the potential capability of a relatively new and unexplored signal-based approach for shipboard wave estimation. The approach uses the phase-time-path-differences (PTPDs) from an array of shipboard ... -
Sea state estimation based on vessel motion responses: Improved smoothness and robustness using Bezier surface and L1 optimization
Ren, Zhengru; Han, Xu; Verma, Amrit Shankar; Dirdal, Johann Alexander; Skjetne, Roger (Peer reviewed; Journal article, 2021)Floating structures oscillate in waves, where these wave-induced motions may be critical for various marine operations. An important consideration is thereby given to the sea states at the planning and operating stages for ... -
Signal-based sea state estimation: A phase-time-path-difference approach: A new shipboard wave estimation approach
Dirdal, Johann Alexander (Doctoral theses at NTNU;2024:79, Doctoral thesis, 2024)The safety and efficiency of marine operations at sea rely on accurate information about the sea state, which includes the dominant wave height, wave direction, and wave period. Unfortunately, many areas at sea lack this ...