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Date of Award

2017

Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Ossama Abdelkhalik

Committee Member 1

Mahdi Shahbakhti

Committee Member 2

Wayne W. Weaver

Abstract

A multi-resonant control was recently developed that maximizes the harvested energy of wave energy converter. Signal processing required in the implementation of the multi-resonant control has been computationally expensive. This thesis implements Recursive Least Squares (RLS) in multi-resonant control. First, a computationally inexpensive approach containing two RLS filters is developed. A frequency update is provided by one RLS filter at a particular rate while the second RLS filter uses this frequency update to estimate parameters to be used for control. To test the accuracy of this estimation, computer simulations were carried out on a spherical buoy using Bretschneider spectrum under different sea states. The results obtained from these simulations show that the controller approximately produces the same amount of energy as that obtained using the complex conjugate control. In addition, this approach was able to adapt for time-varying sea states as well. In addition, to handle position constraints, a switching strategy is implemented that switches between a non-linear damping control and multi-resonant control. Simulation results for constraint handling are provided and effect of different motion constraints on the energy developed is studied.

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