Potential (passive) flight stabalization and control mechanisms for flapping robotic bird flight

Finished: 2022-10-14

MSc assignment

Bird-flight is a complicated problem. Control systems need to deal with many unsteady phenomena and the physical implementation of any flapping flight mechanism needs to be very strong, yet very light-weight in order for it to have any hope to fly at all.
One extreme maneuvre birds perform is the landing. Non-long-distance birds, such as eagles (Aquila nipalensis, or ‘steppe eagle’ in this specific case) perform a break maneuvre just before touch-down. During this maneuvre they tilt their wings to have an extreme angle-of-attack, where the wings basically only function as parachutes/air-brakes. Such a flight profile poses a significant control problem but has been demonstrated to be possible with fixed wing aeroplanes as well.

However, birds have an advantage over human-made fixed-wing aircraft, their wings can change during the landing. Not just by extending/retracting their wings, but their covert feathers can deflect during flapping perching sequences, as well as having potentially fine-grained control with the handwing/allula. The effect of lifting covert feathers has been observed in nature and has been posed to potentially aid in landing (control). However, there seems to be, so far, no quantitave data available that shows if, and to what degree, this mechanism of lifting covert feathers aids during such extreme flapping maneuvres.

Therefore this research focusses on attempting to create, implement and study a similar mechanism to e.g. the covert feather lifting, and its effects on such things as control, lift/drag and potential energetic benefits during (extreme) flapping flight maneuvres, such as landing.