Optimization of flapping wing mechanism of bionic eagle

Abstract

The present study is focused on optimization of a double-crank-rocker flapping wing mechanism to imitate the motion of eagle wing divided into inner and outer wing with flapping, folding and twist degree of freedom, and structural flexibility. Considering the multibar dimensions of the flapping mechanism as design variables, combinatorial optimization method was applied to maximize the aerodynamic efficiency. Based on the optimization results, a bionic eagle model of 1.5 m wing span was manufactured to perform flight tests. The study results show that the optimized kinematic of motion can be achieved by using the multibar flapping mechanism; the inner wing plays the key role of producing lift while the outer wing producing thrust; as a result of the optimization, the lift was increased by 2.8% from 3.85 N up to 3.96 N and the thrust increased by 12.5% from 0.16 N up to 0.18 N, which was verified by the flight tests. The flight test also demonstrated a sustainable level flight of the bionic eagle model at a flapping frequency of 2 Hz.