Bionic flapping wing structural parameter optimization based on lift maximization

Abstract

To address the issues of short endurance and poor flight performance of flapping wing aircraft, this study focuses on the double-crank double-rocker two-segment flapping wing mechanism and conducts structural parameter optimization research based on lift maximization. First, the complex vector method is used to derive the kinematic models of the four-bar mechanism and the two-segment flapping wing mechanism, establishing the intrinsic relationship between “geometric parameters and flapping wing motion laws”. Combined with the lift formula, a quantitative relationship between “geometric parameters, flapping velocity, and lift” is constructed. With the goal of maximizing the average lift, the genetic algorithm is applied to optimize the key geometric parameters of the mechanism. Finally, numerical simulations of the aerodynamic characteristics of the flapping wing mechanism before and after optimization are carried out to verify the optimization effect. The results show that after optimization, the swing range of the inner wing expands from approximately 57° to 90°; the folding speed of the inner and outer wings during the upstroke is significantly increased, reducing the resistance in the upstroke process; the deployment speed during the downstroke is increased, enhancing the lift in the downstroke process. Meanwhile, as the incoming flow velocity or flapping frequency increases, the growth rates of the net lift and net thrust of the optimized flapping wing are significantly higher than those before optimization. The research results of this paper provide theoretical support and technical references for the selection and parameter design of transmission mechanisms for high-performance flapping wing aircraft.