Optimal Stiffness Design of a Twistable Flapping Rotary Wing in Hovering Flight

Abstract

The flapping rotary wing (FRW) is a novel bio-inspired layout for micro air vehicles, which combines the features of insect-like flapping wings and conventional rotary wings. To date, the impact of wing deformation on the performance of FRW is still underexplored since a numerical solution requires considerable computational resources. Using a reduced-order fluid-structure interaction (FSI) model for hovering FRW and the genetic algorithm, an optimization for the wing-root stiffness (k1) and elastic modulus (E) of twistable FRWs are conducted within flapping frequency (f) = 10–25 Hz and amplitude (θm) = 10°–20°. The optimal k1 and E values to achieve the lift maximum and efficiency maximum at each combination of f and θm are summarized, together with the corresponding passive pitching motion and spanwise twisting. These findings can guide the wing design of hovering FRWs when spanwise twisting dominates the wing deformation.