Aerodynamic optimization of a micro flapping rotary wing in hovering flight

The aerodynamic characteristics of flapping rotary wings (FRWs) have received considerable attention in design. In this study, optimizations of aerodynamic performance and kinematics of FRWs over the parameter space are explored. A well-validated Quasi-Steady model is employed to estimate the aerodynamic characteristics of FRWs in hovering flight, and a genetic algorithm is utilized for optimizing. It is assumed that flapping and pitching motion are given by motion parameters actively, while rotation is produced passively. Our results show that the optimal kinematic parameters are independent of flapping frequencies. The maximum lift comes from the high rotational speed caused by the small pitching amplitude, and the maximum power factor is from the large pitching amplitude. The dimensionless optimization of the flapping velocity as reference velocity is comparable to the dimensional results. The optimization model proposed in this study can be applied to the actual model for qualitative analysis. Rotational equilibrium power factor can reach more than 80% of the maximum value without rotation equilibrium constraint, but which rotational status can achieve the maximum power factor depends on the pitching angle at the mid-downstroke (α_d). This study is helpful for the kinematic parameter design and further research of FRWs.