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The objective of this research was to quantify the undesired pitch and heave motions caused by wave-induced loads on a remotely operated vehicle (ROV) operating near the surface. Accomplishing this objective will help to inform system design requirements necessary to ensure desired performance during operations. An experimental study was conducted utilizing a towing tank with wave-making capability and a commercially available ROV. The ROV was tested in the tank at near-surface depths using both single-component and two-component waves for zero speed and forward speed conditions. Pitch, depth, and thruster data were collected from the ROV and compared against control runs to determine the effect of the wave-induced loads on the ability of the ROV to control pitch and maintain depth. For pitch, the results showed that the response had components from linear loads, nonlinear loads, and natural system frequencies. Linear loads resulted in a pitch response that increased with wavelength and ROV speed. Low-frequency nonlinear loads resulted in a measurable pitch response at the wave component frequency differences used. Natural system frequencies resulted in a pitch response at frequencies specific to the ROV, and this response increased with speed. For depth, little response was seen due to the control authority of the ROV; however, the vertical thruster response showed that wave-induced loads have the potential to affect depth if sufficient control authority is not present. Outstanding Thesis Lieutenant, United States Navy Approved for public release. distribution is unlimited |
