Experimental optimization of wing shape for a hummingbird-like flapping wing micro air vehicle

TLDR

Flapping‑wing MAVs emulate insects and hummingbirds, yet material differences limit how closely wing motion and shape can be replicated. This study experimentally optimizes the wing shape of a flexible hummingbird‑sized MAV. Experiments varied wing slackness (camber angle), aspect and taper ratios, and surface area, measuring lift and power efficiency. Camber angle and aspect ratio strongly influence performance; the optimal design is a trapezoidal wing with a straight leading edge and aspect ratio 9.3, enabling lift‑off of a 17.2‑g robot.

Abstract

Flapping wing micro air vehicles (MAVs) take inspiration from natural fliers, such as insects and hummingbirds. Existing designs manage to mimic the wing motion of natural fliers to a certain extent; nevertheless, differences will always exist due to completely different building blocks of biological and man-made systems. The same holds true for the design of the wings themselves, as biological and engineering materials differ significantly. This paper presents results of experimental optimization of wing shape of a flexible wing for a hummingbird-sized flapping wing MAV. During the experiments we varied the wing 'slackness' (defined by a camber angle), the wing shape (determined by the aspect and taper ratios) and the surface area. Apart from the generated lift, we also evaluated the overall power efficiency of the flapping wing MAV achieved with the various wing design. The results indicate that especially the camber angle and aspect ratio have a critical impact on the force production and efficiency. The best performance was obtained with a wing of trapezoidal shape with a straight leading edge and an aspect ratio of 9.3, both parameters being very similar to a typical hummingbird wing. Finally, the wing performance was demonstrated by a lift-off of a 17.2 g flapping wing robot.