CU: Cockroach-inspired robot among smallest, fastest ever created

Thursday June 4, 2020 0 comments Tags: Boulder, CU Boulder, Kaushik Jayaram, HAMR-Jr

BOULDER -- Say hello to HAMR-Jr, the little robot -- inspired by insects -- that can do incredible things.

This machine, the brainchild of University of Colorado Boulder engineer Kaushik Jayaram and colleagues at Harvard University, gives a whole new meaning to the word small: HAMR-Jr can just about squeeze onto the surface of a penny and weighs far less than a paperclip.CU_logoUSE_1 

But don’t let its size fool you. This four-legged robot can also carry up to 10 times its own weight in cargo and hits top speeds that, for its size, are comparable to a cheetah bounding over the Serengeti.

"HAMR-Jr can achieve gaits that approach an animal-like mechanical dexterity, demonstrating that we do not need to compromise design complexity or manufacturability to reduce the size of our robots,” said Jayaram, an assistant professor in the Paul M. Rady Department of Mechanical Engineering.

Jayaram led the design of this little-robot-that-could while he was working as a postdoctoral scholar in Harvard’s Microrobotics Lab led by Professor Robert Wood. (HAMR stands for the Harvard Ambulatory MicroRobot). It’s half the length of its predecessor, HAMR-VI, making it one of the smallest and fastest robots in the world.  

The engineer has big plans for little robots like it. One day, Jayaram said, machines the size of HAMR-Jr could crawl into airplane engines or other spaces where mechanics can’t reach to conduct needed inspections. They might even perform surgeries on human patients.

“I want to build robots that can get out of the lab and run around like bugs,” he said.

Jayaram will present his group’s results virtually this week at the International Conference on Robotics and Automation (ICRA 2020). 

HAMR-Jr was designed to mimic the speed and maneuverability of one insect in particular: the much-maligned cockroach. That brought its own set of engineering challenges.

Take power. Traditional motors won’t work in a robot this size. They overheat when they get too small. So, the Harvard team powered HAMR-Jr using tools called “piezoelectric actuators”— thin materials that bend when you hit them with an electric voltage. 

HAMR-Jr may also be one of the most high-tech paper airplanes out there. To make a robot that small, researchers began by using a laser to etch the shape of its body parts into a sheet of carbon fiber composite. 

“We make everything in a plane as a two-dimensional structure and fold it up like origami to make the three-dimensional structure,” Jayaram said. “It takes a lot of time looking under a microscope to get it to work.”

Those sore eyes paid off: HAMR-Jr can turn right and left and even scoots backward. It also runs at a pace of nearly 14 of its own body lengths, or about one foot, per second. For comparison, cheetahs, the speed demons of the mammal world, sprint at roughly 16 body lengths per second.

HAMR-Jr is just the beginning, Jayaram added. Engineers could, theoretically, use his team’s same methods to make even more petite robots -- as small as a pencil eraser or smaller.

“We showed that our design and fabrication methodology is scalable,” Jayaram said. “We could shrink everything down or scale it up, and the robot would still work.”

Coauthors on the new study include Harvard researchers Jennifer Shum, Samantha Castellanos, E. Farrell Helbling and Robert Wood.