ENME Press Release Story

No Electrical Outlet, No Problem for UMD Robotic Bird That Harvests Solar Energy

Micro air vehicle's solar cell wings feed on the sun, provide energy for the long haul

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Rebecca Copeland
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The Robo Raven III team (L-R) S.K. Gupta, Luke Roberts, Ariel Perez-Rosado and Hugh Bruck.

Small robotic birds are showing lots of promise for tasks such as monitoring the environment and surveillance. But one current drawback they have is the amount of time they're able to stay aloft. Because of the birds' light weight and small size, the tiny batteries used to power them deplete in just a few minutes.

University of Maryland Professors S.K. Gupta and Hugh Bruck and their students in the Maryland Robotics Center are working on a solution that will allow longer flights and battery recharging in remote places without electrical outlets. The Clark School of Engineering team has developed and demonstrated a new version of its Robo Raven micro air vehicle (MAV) that incorporates solar panels in its wings.

While the solar panels don’t yet produce enough energy to power Robo Raven III in flight (they produce around 3.6 Watts while Robo Raven needs around 30 Watts to fly), they are effective in charging the MAV’s batteries when it is stationary.

Gupta notes that the development team envisions Robo Raven flying "far away from civilizations" during long missions and needing "a way to 'feed' itself" on its journeys.

Because Robo Raven's large wings have enough surface area to create a usable amount of solar energy, the team decided to incorporate flexible solar cells into them. The captured solar energy is then used to supply Robo Raven's onboard batteries. "These new multi-functional wings will shape the future of robotic birds by enabling them to fly longer, farther, and more independently because they will be getting their power from the sun" says Mechanical Engineering Ph.D. student Luke Roberts, a member of the Robo Raven team.

The underlying material of the flexible solar panels is different from that used in the previous version of Robo Raven. That meant the team needed to design new wings and develop a new additive manufacturing process to fabricate them, Gupta says.

"We still need to make significant improvements in solar cell efficiency and battery energy density to replicate the endurance of real ravens in Robo Raven III," Gupta says, "but the good news is that Robo Raven III has already demonstrated we can fly with a solar cell and battery combination. Now that we've successfully taken this step, swapping new technologies that are more efficient should be relatively simple."

Gupta has been working on flapping-wing robotic birds for the better part of a decade. His team first successfully demonstrated a flapping-wing bird in 2007. Robo Raven, the first flapping-wing MAV with independent, programmable wings, was introduced this spring. Gupta holds a joint appointment in Mechanical Engineering and the Institute for Systems Research, and Bruck is a Mechanical Engineering professor.


More Information: 

This work was funded in part by the Air Force Office of Scientific Research.

S.K. Gupta’s blog post about Robo Raven III: unorthodoxideas.blogspot.com
Robo Raven III YouTube video: youtu.be/t1_mPe8Y0V4

More about the Robo Raven: www.isr.umd.edu/news

Maryland Robotics Center YouTube channel: www.youtube.com/umdrobotics
See Robo Raven III at Maryland Robotics Day, October 25: robotics.umd.edu/Md_robo_day

High-resolution photos of Robo Raven III

The Robo Raven III team. Caption: The Robo Raven III team (L-R) S.K. Gupta, Luke Roberts, Ariel Perez-Rosado and Hugh Bruck. Credit: Luke Roberts, University of Maryland

Robo Raven III close-up. Caption: A close-up of Robo Raven III, with solar cell wings. Credit: Luke Roberts, University of Maryland

About the University of Maryland

The University of Maryland ranks among the top 20 public research universities in the nation, and is the closest in proximity to the nation’s capital. As the state’s flagship university, UMD educates the most talented students from Maryland and beyond. For more information, please visit:

The University of Maryland: www.umd.edu
The A. James Clark School of Engineering: www.eng.umd.edu
The Maryland Robotics Center: robotics.umd.edu
The Institute for Systems Research: www.isr.umd.edu
The Department of Mechanical Engineering: enme.umd.edu