The design and construction of a Bio-mimetic Flapping Foil AUV is detailed. The vehicle was designed as a proof of concept for the use of oscillating foils as the sole source of motive power for a cruising and hovering underwater vehicle. Primary vehicle design requirements included scalability and flexibility in terms of the number and placement of foils, so as to maximize experimental functionality. This goal was met by designing an independent, self-contained module to house each foil, requiring only 24V DC power and a connection to the vehicle's Ethernet LAN for operation. All other vehicle components are contained in housings which can be repositioned to any point on the central aluminum spine that comprises the vehicle frame. The results of tests on the foil modules in the MIT Marine Hydrodynamics Water Tunnel and MIT Ship Model Testing Tank are used both to demonstrate fundamental properties of flapping foils, and to predict the performance of the specific vehicle design based on the limits of the actuators. The maximum speed of the vehicle is estimated based on the limitations of the specific actuator, and is shown to be a strong function of the vehicle drag coefficient. When using four foils, the maximum speed increases from 1m/s with a vehicle C{sub}D of 1.4 to 2m/s when C{sub}D = 0:1, where C{sub}D is based on vehicle frontal area. Finally, issues of vehicle control are considered, including the decoupling of speed and pitch control using pitch biased maneuvering, and the trade-off between actuator bandwidth and authority both during cruising and hovering operation.
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