Next-Generation drones master dynamic soaring

Albatrosses have 11ft wingspans that carry them across oceans. But it’s how they use these wings that makes them world-class flyers, according to a University of Cincinnati aerospace engineering professor.

UC Assistant Professor Sameh Eisa and his research partners hope to harness the birds’ amazing abilities for the next generation of drones.

Eisa received a $700,000 grant from the Defense Advanced Research Projects Agency (DARPA) to develop innovations in unmanned aerial vehicles (UAVs) using biomimicry – animal-inspired engineering.

The project is based on his breakthroughs in developing model-free, real-time flight controls to harness the natural abilities of the albatross.

Albatrosses use dynamic soaring to master the wind for distance and time in the air. The birds (and their drone-mimic) identify the minimum and maximum pitch, yaw, roll, and air speeds needed for optimal efficiency.

The birds tack into the wind like a sailboat to gain lift and altitude, finding faster air currents as they climb. When they lose the forward momentum needed to stay in the air, they turn, harnessing gravity’s kinetic energy and wind to propel them forward. At the bottom of this glide, sometimes mere inches off the water, they turn back into the wind and do it again without wasting a single wingbeat.

Eisa says, “GPS trackers show these birds can fly hundreds of miles a week. By the time they die, they’ve flown 20x the distance between the Earth and the moon.”

The birds also gauge wind speed and direction through their sensitive nostrils, allowing them to make fine flight adjustments to optimize their flight path.

Eisa’s analyses show energy from the wind balances energy lost in flight. Meanwhile, the total energy of each dynamic soaring cycle is nearly constant. In simulations, Eisa found computers could do no better than the birds at charting the optimal course in real time.

For a drone to achieve autonomous soaring and fly like an albatross, it must measure changing wind speeds and direction to calculate the best angle of attack and rolling action to adjust flight controls in real time.

Eisa and his students are collaborating with researchers in industry, weather experts, and the Massachusetts Institute of Technology (MIT) on a project called Albatross.

Traditionally, wind is the enemy of drones, Eisa says, but their project is trying to turn this obstacle into an advantage.

Researchers will test, validate, and implement new flight control designs and methods in experiments by UC’s DARPA industrial team to demonstrate how much energy dynamic soaring saves compared to normal flight.

“Nature has been optimizing flight for millions of years of evolution,” Eisa says. “To take this gift from nature and make it available to humanity is engineering at its best.”

University of Cincinnati College of Engineering and Applied Science
https://ceas.uc.edu