Publications

Bacelli, Giorgio B.; Coe, Ryan G.

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Coe, Ryan G.

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Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE

Coe, Ryan G.; Bacelli, Giorgio B.; Wilson, David G.

A linear dynamic model for a wave energy converter (WEC) has been developed based on the results of experimental wave tank testing. Based on this model, a model predictive control (MPC) strategy has been designed and implemented. To assess the performance of this control strategy, a deployment environment off the coast of Newport, OR has been selected and the controller has been used to simulate the WEC response in a set of irregular sea states. To better understand the influence of model accuracy on control performance, an uncertainty analysis has been performed by varying the parameters of the model used for the design of the controller (i.e. the control model), while keeping the WEC dynamic model employed in these simulations (i.e. the plant model) unaltered. The results of this study indicate a relative low sensitivity of the MPC control strategy to uncertainties in the controller model for the specific case studied here.

Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE

Coe, Ryan G.; Bacelli, Giorgio B.; Wilson, David G.

A study was performed to optimize the geometry of a point absorber style wave energy converter (WEC). An axisymmetric single-body device, moving in heave only, was considered. Design geometries, generated using a parametric definition, were optimized using genetic algorithms. Each geometry was analyzed using a boundary element model (BEM) tool to obtain corresponding frequency domain models. Based on these models, a pseudo-spectral method was applied to develop a control methodology for each geometry. The performance of each design was assessed using a Bretschneider sea state. The objective of optimization is to maximize harvested energy. In this preliminary investigation, a constraint is imposed on the the geometry to guarantee a linear dynamic model would be valid for all geometries generated by the optimization tool. Numerical results are presented for axisymmetric buoy shapes.

Coe, Ryan G.; Bacelli, Giorgio B.

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Coe, Ryan G.; Bacelli, Giorgio B.

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Coe, Ryan G.; Bacelli, Giorgio B.

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OCEANS 2016 MTS/IEEE Monterey, OCE 2016

Abdelkhalik, Ossama; Zou, Shangyan; Bacelli, Giorgio B.; Robinett, Rush D.; Wilson, David G.; Coe, Ryan G.

Many of the control strategies for wave energy converters (WECs) that have been studied in the literature rely on the availability of estimates for either the wave elevation or the exciting force caused by the incoming wave; with the objective of addressing this issue, this paper presents the design of a state estimator for a WEC. In particular, the work described in this paper is based on an extended Kalman filter that uses measurements from pressure sensors located on the hull of the WEC to estimate the wave exciting force. Simulation results conducted on a heaving point absorber WEC shows that the extended Kalman filter provides a good estimation of the exciting force in the presence of measurement noise combined with a simplified model of the system, thus making it a suitable candidate for the implementation in an experimental set-up.

Kobos, Peter H.; Neary, Vincent S.; Coe, Ryan G.; Hernandez-Sanchez, Bernadette A.

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Coe, Ryan G.; Bacelli, Giorgio B.; Wilson, David G.; Patterson, David

A model-scale wave tank test was conducted in the interest of improving control systems design of wave energy converters (WECs). The success of most control strategies is based directly upon the availability of a reduced-order model with the ability to capture the dynamics of the system with sufficient accuracy. For this reason, the test described in this report, which is the first in a series of planned tests on WEC controls, focused on system identification (system ID) and model validation.

Coe, Ryan G.

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Coe, Ryan G.; Yu, Yi-Hsiang Y.; van Rij, Jennifer v.

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Coe, Ryan G.; Bacelli, Giorgio B.; Wilson, David G.

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Coe, Ryan G.; Bacelli, Giorgio B.

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Coe, Ryan G.

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Wilson, David G.; Bacelli, Giorgio B.; Coe, Ryan G.; Bull, Diana L.; Abdelkhalik, Ossama A.; Korde, Umesh A.; Robinett, R.D.R.

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Michelen Strofer, Carlos A.; Coe, Ryan G.; Yu, Yi-Hsiang Y.; Wang, Qi W.

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Coe, Ryan G.; Michelen Strofer, Carlos A.; Manuel, Lance M.; Canning, Jarred C.

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Coe, Ryan G.; Michelen Strofer, Carlos A.; Eckert, Aubrey C.; Yu, Yi-Hsiang Y.; van Rij, Jennifer v.

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Coe, Ryan G.; Bull, Diana L.; Bacelli, Giorgio B.; Wilson, David G.; Korde, Umesh A.; Robinett, Rush D.; Abdelkhalik, Ossama A.

The operation of Wave Energy Converter (WEC) devices can pose many challenging problems to the Water Power Community. A key research question is how to significantly improve the performance of these WEC devices through improving the control system design. This report summarizes an effort to analyze and improve the performance of WEC through the design and implementation of control systems. Controllers were selected to span the WEC control design space with the aim of building a more comprehensive understanding of different controller capabilities and requirements. To design and evaluate these control strategies, a model scale test-bed WEC was designed for both numerical and experimental testing (see Section 1.1). Seven control strategies have been developed and applied on a numerical model of the selected WEC. This model is capable of performing at a range of levels, spanning from a fully-linear realization to varying levels of nonlinearity. The details of this model and its ongoing development are described in Section 1.2.

Wilson, David G.; Bacelli, Giorgio B.; Coe, Ryan G.; Bull, Diana L.; Abdelkhalik, Ossama A.; Korde, Umesh A.; Robinett, R.D.R.

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Bacelli, Giorgio B.; Coe, Ryan G.; Wilson, David G.; Robinett, Rush D.; Thomas, Gareth T.; Linehan, Daniel L.; Newborn, David N.; Quintero, Miguel Q.

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Coe, Ryan G.; Michelen Strofer, Carlos A.; Manuel, Lance M.; Canning, Jarred C.

Of interest, in this study, is the quantification of uncertainty in the performance of a two-body wave point absorber (Reference Model 3 or RM3), which serves as a wave energy converter (WEC). We demonstrate how simulation tools may be used to establish short-term relationships between any performance parameter of the WEC device and wave height in individual sea states. We demonstrate this methodology for two sea states. Efficient structural reliability methods, validated using more expensive Monte Carlo sampling, allow the estimation of uncertainty in performance of the device. Such methods, when combined with metocean data quantifying the likelihood of different sea states, can be useful in long-term studies and in reliability-based design.

Coe, Ryan G.; Michelen Strofer, Carlos A.; Yu, Yi-Hsiang Y.; Rij, Jennifer V.; Eckert, Aubrey C.

Abstract not provided.

Michelen Strofer, Carlos A.; Coe, Ryan G.; Yu, Yi-Hsiang Y.; Wang, Qi W.

Abstract not provided.