Passively stable flapping flight from hover to fast forward through shift in wing position

Abstract

Flapping Wing Micro Air Vehicles (FWMAVs) hold the potential to both cover large distances and perform precision flights when arrived at destination. However, flying at different speeds leads to a complex control problem for attitude stabilization. Inspired by nature, we present a morphing mechanism that allows tailed FW-MAVs to have a passively stabilized attitude both in fast forward flight and in slow hovering flight. The mechanism displaces the wings and hence aerodynamic center. It is implemented on the DelFly II and tested in-flight in a motion tracking arena. The experimental tests show that the morphing mechanism indeed allows to fly passively stable in multiple flight modes. Just changing the aerodynamic center allows the DelFly II to fly fast forward (∼ 6 m/s, pitch attitude of 10°), transition to slow forward flight (∼ 0.8 m/s, pitch attitude of 55°), and back. The proposed mechanism paves the way for FWMAVs performing long range missions such as search-and-rescue.