Abstract
This study describes and presents preliminary experimental results from a novel prototype energy scavenging system installed in a model 2 m cylindrical autonomous underwater vehicle (AUV). The system, which is based on control moment gyroscope principles, utilises the gyroscopic response of a gimballed flywheel mounted within an AUV body to generate energy from the wave induced rotational motions of the vehicle. This method, using the reaction of a spinning wheel under an input torque to provide an output torque of greater magnitude, orthogonal to the input torque axis and the spin axis provides a means to harvest energy in-situ, without external appendages and additional hydrodynamic drag. The system promises to extend AUV mission durations indefinitely and reduce support vessel time currently required for periodical recharging and redeployment. A description of the system operation, design and experimental results from a series of regular wave tests conducted at zero speed in a towing tank are presented in this study. The results show that the system can harvest energy, with the greatest power generation around resonance, tailing off as the frequency increases and typically non-linear in nature. The system could potentially be applied to any rotationally excited platform e.g. autonomous surface vessels, buoys or boats.