Researchers at RMIT University have developed a bio-inspired robotic bird that is helping scientists better understand how kestrels maintain stable flight in turbulent conditions, with the findings expected to inform the design of more resilient small unmanned aerial vehicles (sUAVs).
According to RMIT, the robotic replica mimics key movements of the nankeen kestrel, allowing researchers to investigate how the bird responds to gusts and turbulence. The work forms part of a multi-year collaboration between RMIT University and the University of Bristol and has been published in two papers in the Journal of the Royal Society Interface.
The research comes as atmospheric turbulence is expected to increase with climate change, creating additional challenges for sUAVs used in applications such as aerial photography, search and rescue, agricultural monitoring and package delivery.
RMIT researcher Matt Penn, who led part of the study examining how birds handle turbulence, said kestrels use multiple strategies to maintain stable flight.
“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.”
Researchers tracked the flight of nankeen kestrels using motion capture technology in RMIT’s Industrial Wind Tunnel facility before developing a robotic replica capable of reproducing the movements considered most important to the birds’ stability.
Dr Mario Martinez Groves-Raines, who conducted the research during his studies at RMIT and the University of Bristol and is now based at the Royal Veterinary College in London, said the robotic bird enabled the team to isolate and measure the effects of specific movements.
“By creating a robot replica, we were able to measure how specific movements were contributing to steadiness in flight,” Groves-Raines said.
“We uncovered several unique techniques behind the kestrel’s impressive stability. Many of these techniques have the potential to improve manoeuvrability of small aircraft, which encounter similar challenges to kestrels.”
RMIT Associate Professor Abdulghani Mohamed said the project demonstrated the value of collaboration between institutions and the potential for nature-inspired engineering.
“This research shows what’s possible when engineers look to nature for solutions,” Mohamed said.
“Our findings open new pathways for designing aircraft that can better handle turbulence.”
According to RMIT, while some turbulence-mitigation approaches used by birds have already been explored for sUAVs, relatively few have been incorporated into operational aircraft because of complexity and efficiency trade-offs.
The research team plans to further investigate how kestrels detect subtle changes in airflow, with the aim of applying those insights to future aircraft designs. Although the current work focuses on smaller aerial vehicles, the researchers said they hope the findings can eventually be adapted for larger aircraft.
RMIT said it is seeking industry partners to help advance the research and support the development of next-generation aircraft technologies.
