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Improving Operational Effectiveness of Tactical Long Endurance Unmanned Aerial Systems (TALEUAS) by Utilizing Solar Power
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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This thesis develops, implements, and validates a hybrid energy-harvesting technique that enables extracting energy from the environment by utilizing convective thermals as a source of potential energy, and exploiting solar radiation for photovoltaic PV energy to achieve long endurance flight of an autonomous glider. The dynamic behavior of convective thermals, as well as their mathematical models, are studied to determine their motion, while the navigation task is simultaneously solved using a Bayesian search approach that is based on the prior knowledge of the 3D elevation. This study advances an existing technique for detection of thermals by implementing the online identification of the airplane sink rate polar. The glider s climb rate is optimized by implementing a modified thermalling controller, and its performance is compared to an existing method of centering in thermals. The integration of the energy extracted from the solar radiation is accomplished by the design of an Electrical Energy Management System EEMS that safely collects and distributes the energy onboard. The electrical energy is supplied by the semi-rigid mono crystalline silicon solar cells, which are embedded into the skin of the glider s wings without distorting the airfoil. To validate and verify the algorithms developed in MATLABSimulink, an interface to a high-fidelity pilot s training flight simulator was designed. Furthermore, the numerical algorithms were integrated onboard a prototype SB-XC glider equipped with solar cells to enable the desired energy-harvesting technique. Flight test results verify the feasibility of the developed algorithms.
APPROVED FOR PUBLIC RELEASE