Park to introduce robotic flying squirrels


Miranda Holloway, MechSE Communications

Illinois researcher Hae-Won Park has been awarded a Robotics Fast Track contract from the Defense Advanced Research Projects Agency (DARPA) to design a hybrid robot that can glide, land, and walk. 
His ground-breaking design connects two widely researched robot forms – UAVs and quadruped robots – and is inspired by the flying squirrel, or Glaucomys volans. This animal can glide between trees and walk on branches to harvest food and escape from predators. 
Park’s robot would be dropped from an aerial vehicle, glide like a flying squirrel, then land and continue walking on a variety of terrains, with proposed applications in reconnaissance missions, military scouting, and disaster response efforts, particularly in difficult-to-access or hazardous environments. 
Other robots that can walk or fly and that are used in these situations, are often met with a number of challenges, such as limited battery life, constrained mobility in tight spaces, and an inability to travel long distances. 
Park’s flying squirrel will address these flaws. The combined mobility of walking and flying will give the bots the large range of coverage of existing flying robots as well as the long-lasting operational hours of a ground vehicle. Additionally, the ability to gather information about environmental conditions is crucial to saving lives. Thus, they can be used independently or in swarms to share environmental awareness via a mobile sensor network. 
While there have been other robots of a similar design, most research has focused on very small robots that could not complete the missions Park believes his robot can accomplish. These smaller bots also tend not to boast complex combinations between walking and gliding, and as a result, they cannot walk well and their wings lack active control.
Park, an assistant professor in the Department of Mechanical Science and Engineering at the University of Illinois at Urbana-Champaign, got the idea for the flying squirrel model while watching a National Geographic Channel documentary called “Super Squirrel” that depicts the animal jumping and gliding between trees to navigate the woods. 
“Their aerodynamic maneuvers are so elegant, dynamic, and efficient,” Park said. “They use their limbs and tails, changing the shape of the wing to steer and control the gliding. That’s where I got my inspiration.”
His design includes development of soft silicone wing structures that will attached to the robot’s limbs and allow it to glide. They will feature adjustable stiffness and morphing abilities, and will serve as a shape-morphing aerodynamic control surface when stretched.
“An ideal material would be both compliant and strong, such that the wing can be stretched to increase the aerodynamically active surface area when gliding and be furled to not obstruct while walking,” Park said. 
This is part of what he calls a multifunctional body frame, i.e. one that has the physical structure to allow the bot to walk and glide. 
The body frame will be 3D-printed with lightweight materials – allowing for fast prototyping – like carbon fiber composite material, engineered plastics, and compliant resins. Other parts will be off-the-shelf components, lowering the cost enough to make the robots expendable after use. The entire bot is estimated to weigh only about 1.5 pounds.  
Park directs the Dynamic Robotics Lab at Illinois. He earned a PhD in mechanical engineering from the University of Michigan in 2012, a master’s degree in mechanical engineering in 2007 from Yonsei University, and a bachelor’s degree, also in mechanical engineering, from Yonsei University in 2005. After holding positions as a Postdoctoral Associate and a Research Scientist at MIT, he joined the MechSE Department at Illinois in September 2015. 
DARPA is an agency of the U.S. Department of Defense responsible for the development of emerging technologies for use by the military.