A design framework for realizing multifunctional wings for flapping wing air vehicles using solar cells
A design framework for realizing multifunctional wings for flapping wing air vehicles using solar cells
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Date
2019-04-10
Authors
Holness, Alex E.
Solheim, Hannah
Bruck, Hugh A.
Gupta, Satyandra K.
Advisor
Citation
Holness, A. E., Solheim, H., Bruck, H. A., & Gupta, S. K. (2019). A design framework for realizing multifunctional wings for flapping wing air vehicles using solar cells. International Journal of Micro Air Vehicles. https://doi.org/10.1177/1756829319836279
DRUM DOI
Abstract
Long flight durations are highly desirable to expand mission capabilities for unmanned air systems and autonomous
applications in particular. Flapping wing aerial vehicles are unmanned air system platforms offering several performance
advantages over fixed wing and rotorcraft platforms, but are unable to reach comparable flight times when powered by
batteries. One solution to this problem has been to integrate energy harvesting technologies in components, such as
wings. To this end, a framework for designing flapping wing aerial vehicle using multifunctional wings using solar cells is
described. This framework consists of: (1) modeling solar energy harvesting while flying, (2) determining the number of
solar cells that meet flight power requirements, and (3) determining appropriate locations to accommodate the desired
number of solar cells. A system model for flapping flight was also developed to predict payload capacity for carrying
batteries to provide energy only for power spikes and to enable time-to-land safely in an area where batteries can
recharge when the sun sets. The design framework was applied to a case study using flexible high-efficiency (>24%) solar
cells on a flapping wing aerial vehicle platform, known as Robo Raven IIIv5, with the caveat that a powertrain with 81%
efficiency is used in place of the current servos. A key finding was the fraction of solar flux incident on the wings during
flapping was 0.63 at the lowest solar altitude. Using a 1.25 safety factor, the lowest value for the purposes of design
will be 0.51. Wind tunnel measurements and aerodynamic modeling of the platform determined integrating solar cells
in the wings resulted in a loss of thrust and greater drag, but the resulting payload capacity was unaffected because of
a higher lift coefficient. A time-to-land of 2500 s was predicted, and the flight capability of the platform was validated
in a netted test facility.
Notes
Partial funding for Open Access provided by the UMD Libraries' Open Access Publishing Fund.