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Title: Pseudo-spectral method to control three-degree-of-freedom wave energy converters

Abstract

The invention provides optimal control of a three-degree-of-freedom wave energy converter using a pseudo-spectral control method. The three modes are the heave, pitch and surge. A dynamic model is characterized by a coupling between the pitch and surge modes, while the heave is decoupled. The heave, however, excites the pitch motion through nonlinear parametric excitation in the pitch mode. The invention can use a Fourier series as basis functions to approximate the states and the control. For the parametric excited case, a sequential quadratic programming approach can be implemented to numerically solve for the optimal control. The numerical results show that the harvested energy from three modes is greater than three times the harvested energy from the heave mode alone. Moreover, the harvested energy using a control that accounts for the parametric excitation is significantly higher than the energy harvested when neglecting this nonlinear parametric excitation term.

Inventors:
; ; ; ; ;
Issue Date:
Research Org.:
National Technology & Engineering Solution of Sandia, LLC, Albuquerque, NM (United States); Michigan Technological Univ., Houghton, MI (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1568571
Patent Number(s):
10,344,736
Application Number:
15/837,853
Assignee:
National Technology & Engineering Solution of Sandia, LLC (Albuquerque, NM); Michigan Technological University (Houghton, MI)
DOE Contract Number:  
NA0003525
Resource Type:
Patent
Resource Relation:
Patent File Date: 12/11/2017
Country of Publication:
United States
Language:
English

Citation Formats

Abdelkhalik, Ossama, Bacelli, Giorgio, Zou, Shangyan, Robinett, III, Rush D., Wilson, David G., and Coe, Ryan G. Pseudo-spectral method to control three-degree-of-freedom wave energy converters. United States: N. p., 2019. Web.
Abdelkhalik, Ossama, Bacelli, Giorgio, Zou, Shangyan, Robinett, III, Rush D., Wilson, David G., & Coe, Ryan G. Pseudo-spectral method to control three-degree-of-freedom wave energy converters. United States.
Abdelkhalik, Ossama, Bacelli, Giorgio, Zou, Shangyan, Robinett, III, Rush D., Wilson, David G., and Coe, Ryan G. Tue . "Pseudo-spectral method to control three-degree-of-freedom wave energy converters". United States. https://www.osti.gov/servlets/purl/1568571.
@article{osti_1568571,
title = {Pseudo-spectral method to control three-degree-of-freedom wave energy converters},
author = {Abdelkhalik, Ossama and Bacelli, Giorgio and Zou, Shangyan and Robinett, III, Rush D. and Wilson, David G. and Coe, Ryan G.},
abstractNote = {The invention provides optimal control of a three-degree-of-freedom wave energy converter using a pseudo-spectral control method. The three modes are the heave, pitch and surge. A dynamic model is characterized by a coupling between the pitch and surge modes, while the heave is decoupled. The heave, however, excites the pitch motion through nonlinear parametric excitation in the pitch mode. The invention can use a Fourier series as basis functions to approximate the states and the control. For the parametric excited case, a sequential quadratic programming approach can be implemented to numerically solve for the optimal control. The numerical results show that the harvested energy from three modes is greater than three times the harvested energy from the heave mode alone. Moreover, the harvested energy using a control that accounts for the parametric excitation is significantly higher than the energy harvested when neglecting this nonlinear parametric excitation term.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {7}
}

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