Soft Limitation of Passive Feathering at Wing Root Improves Lift Generation Performance in Hummingbird-Mimetic Flapping Wings

Abstract

In this study, we introduce a new structure called the “connecting membrane” aiming to improve the performance of hummingbird-mimetic flapping wings. The “connecting membrane” is an extension of the wing membrane at the basal that connects the root shaft and the robot body, it elastically pulls the wing to stop the continuous feathering, thereby curbing feathering in the wing's root chord while promoting twist of the wing. This augmentation in total wing torsion improves lift generation. Tethered flapping experiments conducted at 24 Hz showed that the wing with the connecting membrane integrated achieved 24.2% higher power efficacy and 8.4% higher lift (116 mN) compared to the wing without a connecting membrane that flapped with a rigid limiter.