The robot, reimagined

Alex Hunt’s lab has pioneered a new field inspired by the adaptability of animals

Alex hunt poses with two robots

ALEXANDER HUNT doesn’t think robots are going to take over the world anytime soon.

“People see robot videos and think robots are way better than they actually are,” says Hunt, assistant professor of mechanical engineering and head of Portland State’s Agile and Adaptive Robotics Lab. “Just like anything else you see on the internet, all you see is the good stuff, not the hundred times the robots fell.”

Hunt wants to build better robots—robots that are more agile, more adaptable, robots that can go into harsh environments or do jobs that are dangerous for humans, robots that can help us understand human health. For inspiration, he looks to animals that have been tuned for agility by millions of years of evolution.

Just like anything else you see on the internet, all you see is the good stuff, not the hundred times the robots fell.

Using data from biologists who study locomotion in rats, cats, dogs and humans, Hunt is reverse engineering how animals move. While robots are often designed to look or behave like humans or other animals, Hunt’s approach is unique. His lab is creating robots with electronic controllers that mirror how neurons in the spinal cord control biological limb movement, allowing for more adaptable robotic movement.

Hunt stumbled on the idea of modeling lifelike nervous system control of robotics in graduate school when he and fellow students misinterpreted his adviser’s instructions to “model biological control.”

“He had the foresight to not tell us what we were trying to do was impossible,” says Hunt. “It didn’t work for several years, but we eventually figured out how to make it work.” 

Now Hunt, along with a handful of colleagues throughout the world, is pioneering a new field.
ENTER THE AGILE and Adaptive Robotics Lab and you’ll encounter Muscle Mutt, a four-legged dog-like robot. When Hunt and his colleagues discover ways to replicate how the nervous system works, they try them on this robot.

Mutt will play a critical role in the NeuroNex project, a five-year collaboration between labs at nine different institutions investigating key questions in neuroscience. PSU received $901,000 from the National Science Foundation to test theories of mammalian neural system organization.    

Soon a pair of humanoid legs will join Muscle Mutt. As with Mutt, the legs will be made of 3D-printed, carbon-fiber–infused bones and artificial muscles, which Hunt likens to “finger traps with balloons.”

Hunt’s humanoid legs will be used to study balance as part of a collaboration with Robert Peterka, associate professor of biomedical engineering at Oregon Health & Science University and a research investigator for the U.S. Department of Veterans Affairs.

Peterka has collected data on how human balance changes in different conditions. By building neural controllers that mirror changes in balance in the humanoid robotic legs, the pair hope to better understand how balance is affected by diseases like Parkinson’s as well as how to improve robots’ balance. “Humans are much better at controlling balance than robots,” says Hunt.

HUNT’S LAB is also collaborating with Thomas Schumacher, associate professor of structural engineering at PSU, to build climbing robots to inspect bridges and other large infrastructure—a job that can be dangerous for humans.

“A small swarm of lightweight robot geckos could go around and inspect surfaces of bridges and retaining walls,” says Schumacher. These robots could climb vertical surfaces and even maneuver upside down. They could be equipped with cameras and search for cracks and structural weaknesses by tapping on surfaces—just as human inspectors do—in order to create automated maps of areas of concern.

Concrete climbing robot
This climber is designed to walk like an inchworm up vertical surfaces while inspecting concrete structures such as bridges and dams. The mock-up was designed by senior capstone students Christopher Milojevic, Bretton Fedorczyk, Jen Moua, Kruse Limbocker, Zephyr Weisbart and Jovoni Ashtian.

Recent PSU graduate Jovoni Ashtian ’20 has worked on developing a climbing robot since he joined the lab in 2018. His first job sounds deceptively simple: to design suction cups that stick to concrete. Concrete, which appears smooth, is actually porous. This meant Ashtian had to use a lot of trial and error when designing—and redesigning—the suction cups. 

The first version could only hold for 30 seconds, but eventually Ashtian made a design that held for a full 10 minutes. “It’s just an amazing feeling when you’ve worked so hard, and it actually works,” he says.

This spring, despite having to work remotely due to COVID-19, Ashtian and a team of Capstone students created a design for a complete concrete-climbing robot prototype. Instead of a gecko, this prototype moves more like an inchworm. “The students are quite ingenious,” says Schumacher. “I think this is going to work, and I’m very excited.”

In recognition of his research and mentorship, Hunt recently received a prestigious National Science Foundation CAREER award. He says he’s pleased with the progress the lab is making. 

“I’m very proud that we are getting this to work, and that it is showing a lot of promise,” he says. “The students are full of great ideas and curiosity, and it’s just fun all around.”


Editor's note: An earlier version of this article misstated that Alex Hunt had received a grant from the National Institutes of Health. The grant is from National Science Foundation.

Opening photo by So-Min Kang