The assessment of aerodynamic performance is crucial for designing Flapping-Wing Micro Air Vehicles (FWMAVs), yet limited research has addressed the prediction and analysis of flexible wing aerodynamics during the preliminary design phase. This study proposes an efficient prediction method for the aerodynamic characteristics of flexible flapping wings. A conical surface model is introduced to mimic wing deformation, and the unsteady panel method is employed to predict aerodynamic characteristics. The wing deformation characteristics, the influence of membrane tightness on aerodynamics and the control moments as well as additional moments resulting from coupled control based on the two-winged FWMAV configuration have been investigated. Results indicate that the current prediction method effectively captures the deformation and aerodynamic characteristics of flexible flapping wing. A relatively slack membrane enhances aerodynamic efficiency when the lift is satisfactory. The roll, pitch, and yaw moments correlate linearly with the root vein deflection angle in baseline case, while excessive membrane tension reduces or reverses control effectiveness. The additional roll moment resulting from coupled pitch and yaw controls is significantly greater than the other two additional moments. The findings provide valuable insights for the aerodynamic and control design of flexible flapping wings.

Hover-capable flapping-wing micro air vehicles (FWMAVs), inspired by insects or hummingbirds, exhibit remarkable flight characteristics such as hovering capability, high aerodynamic efficiency at low Reynolds numbers, and strong stealthiness, offering diverse potential applications in disaster rescue, emergency response, and environmental monitoring. However, the aerodynamic forces and efficiency of their flapping wings still lag considerably behind those of their biological counterparts, adversely affecting the endurance and payload capacity of FWMAVs and significantly limiting their practical applications. This paper provides a comprehensive overview of hover-capable FWMAVs, with a focus on current research progress, theoretical and experimental methods for aerodynamic analysis, the high-lift mechanisms of insects and their applications in FWMAVs, as well as aerodynamic design methods and performance evaluation of flapping wings. The review highlights key design parameters for achieving high lift, high aerodynamic efficiency, and low noise, and elucidates the impact of these parameters on the performance of FWMAVs. Finally, future trends in aerodynamic design for hover-capable FWMAVs are discussed, offering valuable guidance for future research in this field.