Nathan Slegers, PhD is a Professor of Mechanical Engineering. His research emphasizes improving actively controlled systems by combining modeling, unique control methods and innovative sensor systems. Recent funded research projects span a variety of systems including: precision guided airdrop systems, butterfly inspired micro air vehicles for the National Science Foundation, and intelligent munitions for the Army Research Laboratory.
Butterfly Inspired Innovations in Unmanned Systems
Innovations in autonomous systems continue to expand their use in our everyday lives. Yet, with regard to small aerial robots, we are still far from the swarms of autonomous insects often portrayed in science fiction films. The limitation is not due to our ability to mechanically build insect size robots; in fact mechanically functioning insect size robots already exist. The practical limitation is energy storage and efficiency.
Taking inspiration from Monarch butterflies and their unique wing scales, a bioinspired solution to drag reduction has the potential to impact aerial robots by improving their efficiency. Butterflies and their colored wing scales have been extensively studied for their optical properties which are often assumed to contribute to mating and natural defenses. However, the aerodynamic benefit from the scales’ microgeometry has garnered much less attention. While there exists a misconception that butterflies need their scales to fly, no complete aerodynamic explanation as to how the scales benefit the butterfly has been accepted.
In order to investigate the potential benefit butterfly wing scales have to their efficiency, a method to measure butterfly flapping kinematics over long uninhibited flapping sequences has been developed. Statistical results based on more than 200 flights, both with and without their wing scales have shown, that for each butterfly, the mean efficiency decreased by 38% after scales were removed. Analysis also showed that the wing flapping amplitude decreased by 7% while the flapping frequency showed no significant difference.
Results provide convincing evidence that wing scale geometry may function to improve aerodynamic efficiency and could similarly be used on flapping wing micro air vehicles to potentially achieve similar gains in efficiency.