Bioinspired wing and tail morphing extends drone flight capabilities

Abstract

The aerodynamic designs of winged drones are optimized for specific flight regimes. Large lifting surfaces provide maneuverability and agility but result in larger power consumption, and thus lower range, when flying fast compared with small lifting surfaces. Birds like the northern goshawk meet these opposing aerodynamic requirements of aggressive flight in dense forests and fast cruising in the open terrain by adapting wing and tail areas. Here, we show that this morphing strategy and the synergy of the two morphing surfaces can notably improve the agility, maneuverability, stability, flight speed range, and required power of a drone in different flight regimes by means of an avian-inspired drone. We characterize the drone’s flight capabilities for different morphing configurations in wind tunnel tests, optimization studies, and outdoor flight tests. These results shed light on the avian use of wings and tails and offer an alternative design principle for drones with adaptive flight capabilities.

Gull-inspired joint-driven wing morphing allows adaptive longitudinal flight control

“…In addition, UAVs often face aerodynamic control challenges including the need to adapt to variable environmental conditions [9] or manoeuvre through complex territories [10], while birds complete similar tasks with apparent ease. Therefore, it is of no surprise that as engineers strive towards the objective of an adaptive, multifunctional UAV, bird wings have directly and indirectly inspired many morphing wing designs [6,[11][12][13][14][15].…”

Bio‐Inspired Large‐Area Soft Sensing Skins to Measure UAV Wing Deformation in Flight

“…Preliminary research on simplified hawkmoth wings indicates that this co‐design is very likely the case in biology. [ 57 ] In certain cases (e.g., UAVs with membrane‐based or soft wings [ 5,6,58 ] ), the soft sensing skin could more directly translate to embedding sensors in the wing membrane. The large‐area soft sensing skins from this work are expected to open up a pathway toward distributed mechanosensing allowing for fast and robust control in complex systems.…”

“…One approach toward more stable UAV flight in a wider range of atmospheric conditions is to make the UAV's morphology adaptable as demonstrated in several instances of “soft” aerial vehicles. [ 4–6 ] A second approach, taken in this work, is inspired by the mechanosensory systems of these small insects. Stable and agile flight in small UAVs will need both the ability to robustly sense disturbances earlier and react to them faster like their biological cousins.…”

Raptor wing morphing with flight speed

“…Wing sweep alone, with minimal area change, allows wings to operate at high lift-to-drag ratios over a wide range of speeds [ 6 ]. When changes in wing sweep are combined with either wing area [ 7 ], tail area [ 8 ] or camber profile [ 9 ], the flight envelope can be enhanced further [ 9 ]. Additionally, tail morphing alone can also reduce the cost of flight through changing pitch or tail spread [ 10 ] because the tail plays an important role in modulating the lift distribution over the bird [ 11 ].…”

“…Additionally, tail morphing alone can also reduce the cost of flight through changing pitch or tail spread [ 10 ] because the tail plays an important role in modulating the lift distribution over the bird [ 11 ]. Related, when an avian-inspired robot, capable of wing sweep and tail contraction, was optimized for the power cost of flight, it used a broadly similar pattern of coordination with speed to that of birds [ 8 ].…”