Development and validation of a lumped-mass dynamics model of a deep-sea ROV system

Citation
Fr. Driscoll et al., Development and validation of a lumped-mass dynamics model of a deep-sea ROV system, APPL OCEAN, 22(3), 2000, pp. 169-182
Citations number
20
Categorie Soggetti
Civil Engineering
Journal title
APPLIED OCEAN RESEARCH
ISSN journal
01411187 → ACNP
Volume
22
Issue
3
Year of publication
2000
Pages
169 - 182
Database
ISI
SICI code
0141-1187(200006)22:3<169:DAVOAL>2.0.ZU;2-1
Abstract
A one-dimensional finite-element lumped-mass model of a vertically tethered caged ROV system subject to surface excitation is presented. Data acquired during normal operation at sea are used with a least-squares technique to estimate the coefficients required by the model. The model correctly predic ts: (a) the motion of the cage and the tension in the tether at the ship; ( b) the spectrum of cage acceleration in the wave-band; (c) the transfer fun ction between the vertical motion of the ship and cage; and (d) the natural frequency of the system and its harmonics. A simple model of the wake of t he cage was added to the model simulation and this reduced the error in the calculated motion and tension by almost a factor of two and brought the ca lculated transfer function within the 95% confidence interval of the measur ements. By increasing ship motion slightly, the model accurately reproduced eight snap loads and their non-linear characteristics-a regularly spaced s eries of rapid increases in the records of the acceleration of the cage and tension at the ship-that occurred during the measurements used for validat ion. (C) 2000 Elsevier Science Ltd. All rights reserved.