Solar cell as wings of different sizes for flapping-wing micro air vehicles

Currently, the biggest challenge for flapping-wing micro air vehicles is their very short flight duration due to limited on-board energy storage capacity. To overcome this challenge, a concept of solar-cell-flapping-wing micro air vehicle is herein proposed and studied. Thirty-three types of currently successful flapping-wing micro air vehicles (including insectlike, bird-like, and hummingbird-like flapping-wing micro air vehicles) are analyzed to explore scaling laws of flapping-wing micro air vehicles. The influences of wingspan, wing area, flapping frequency, and power on mass of flapping-wing micro air vehicles are studied. A dynamic energy harvesting model of solar-cell-flapping-wing is built up and utilized to formulate energy supply rate equations of three types of flapping-wing micro air vehicles. Considering the averaged ground solar spectral irradiance and today's energy conversion efficiency of solar cells, the variation of energy supply rate by scales is analyzed. Several critical parameters to design an efficient long duration flapping-wing micro air vehicle are suggested.