Researchers have built a robotic replica of a nankeen kestrel to study how the bird's exceptional hovering ability could inform the design of safer, more capable small unmanned aerial vehicles (sUAVs).
The research, a multi-year collaboration between RMIT University and the University of Bristol, used motion capture technology in RMIT's Industrial Wind Tunnel facility to track kestrel movements in gusty and turbulent conditions. The findings have been published across two papers in the Journal of the Royal Society Interface.
RMIT researcher Matt Penn said birds employ multiple strategies simultaneously to manage rough air — something sUAVs currently struggle to replicate.
"Birds don't rely on a single response to wind gusts," Penn said. "They constantly adjust their wings and tails to stay balanced, while the natural flexibility of their feathers and joints helps absorb sudden changes in airflow. They can also sense disruptions very quickly, which allows them to respond almost instantly and maintain control."
The robotic replica allowed researchers to precisely measure the forces generated by specific wing and body movements. Dr Mario Martinez Groves-Raines, who completed the research at RMIT and Bristol, said several unique techniques behind the kestrel's stability were uncovered with potential applications for small aircraft design.
"Many of these techniques have the potential to improve manoeuvrability of small aircraft, which encounter similar challenges to kestrels," he said.
sUAVs are widely used for aerial photography, search and rescue, agricultural monitoring and package delivery, but are frequently grounded in turbulent conditions — a problem expected to worsen as climate change increases atmospheric turbulence.
RMIT is seeking industry partners to advance the research. Interested organisations can contact research.partnerships@rmit.edu.au.