Self Powered Autonomous Underwater Vehicles (AUVs): Results from a gyroscopic energy scavenging prototype

This paper describes and presents preliminary experimental results from a novel prototype energy scavenging system installed in a model 2m cylindrical Autonomous Underwater Vehicle (AUV). The system, which is based on control moment gyroscope (CMG) 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, of 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 paper. The results show that the system can harvest energy, with greatest power generation around resonance, tailing off as the frequency increases and typically nonlinear in nature. The results show that the system could provide additional hotel load or power specific systems on an AUV and potentially any rotationally excited platform, e.g., Autonomous Surface Vessels (ASVs), Buoys or Boats. Index Terms AUVs, ASVs, Energy scavenging, Energy harvesting, Renewables, Power, Gyroscopic, Gyroscopes