Biomimetic oscillating foil propulsion to enhance underwater vehicle agility and maneuverability
Licht, Stephen Carl
MetadataShow full item record
Inspired by the swimming abilities of marine animals, this thesis presents "Finnegan the RoboTurtle", an autonomous underwater vehicle (AUV) powered entirely by four flapping foils. Biomimetic actuation is shown to produce dramatic improvements in AUV maneuvering at cruising speeds, while simultaneously allowing for agility at low speeds. Using control algorithms linear in the modified Rodrigues parameters to support large angle maneuvers, the vehicle is successfully controlled in banked and twisting turns, exceeding the best reported AUV turning performance by more than a factor of two; a minimum turning radius of 0.7BL, and the ability to avoid walls detected> 1.8BL ahead, are found for cruising speeds of 0.75BL/S, with a maximum heading rate of 400 / S recorded. Observations of "Myrtle", a 250kg Green sea turtle (Chelonia mydas) at the New England Aquarium, are detailed; along with steady swimming, Myrtle is observed performing 1800 level turns and rapidly actuating pitch to control depth and speed. Limb kinematics for the level turning maneuver are replicated by Finnegan, and turning rates comparable to those of the turtle are achieved. Foil kinematics which produce approximately sinusoidal nominal angle of attack trace are shown to improve turning performance by as much as 25%; the effect is achieved despite limited knowledge of the flow field. Finally, tests with a single foil are used to demonstrate that biomimetically inspired inline motion can allow oscillating foils utilizing a power/recovery style stroke to generate as much as 90% of the thrust from a power/power stroke style motion.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2008
Showing items related by title, author, creator and subject.
Six degree of freedom vehicle controller design for the operation of an unmanned underwater vehicle in a shallow water environment Hajosy, Michael F. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1994-09)Closed loop control of an unmanned underwater vehicle (UUV) in the dynamically difficult environment of shallow water requires explicit consideration of the highly coupled nature of the governing non-linear equations of ...
Shah, Vikrant P. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-06)Autonomous Underwater Vehicles (AUVs) have been established as a viable tool for Oceanographic Sciences. Being untethered and independent, AUVs fill the gap in Ocean Exploration left by the existing manned submersible ...
Kalman filter estimation of underwater vehicle position and attitude using Doppler velocity aided inertial motion unit Leader, Daniel Eugene (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1994-09)This Paper explores the use of an extended Kalman filter to provide real-time estimates of underwater vehicle position and attitude. The types of previously available sensors are detailed including strapdown accelerometers, ...