Origami principles can unlock the potential of the smallest robots, enhancing speed, agility, and control in machines no more than a centimeter in size, researchers report.
The researchers have demonstrated that behavioral rules underpinning the Japanese art of folding can expand the capabilities of these machines. That could create potential for greater use in fields as diverse as medical equipment and infrastructure sensing.
The microbots can fold as far as 90 degrees and more. Larger folds allow microbots to form more complex shapes.
“We’ve come up with a new way to design, fabricate, and actuate microbots,” says Evgueni Filipov, an assistant professor of civil and environmental engineering at the University of Michigan.
“We’ve been the first to bring advanced origami folding capabilities into one integrated microbot system.”
Their bots can form one shape, complete a task, then reconfigure into a second shape for an additional task, and so on.
To date, most microbots have limited movements, which hampers their ability to perform useful tasks. To increase their range of motion, the robots need to be able to fold at large angles. The researchers’ new microbots can fold as far as 90 degrees and more. Larger folds allow microbots to form more complex shapes.
The approach enables microbots to complete their range of motion up to 80 times per second, a faster pace than most can operate.
Microbots using origami principles often require an outside stimulus to activate, such as heat inside a body or a magnetic field applied to the microbot. The new robots utilize a layer of gold and a layer of polymer that act as an onboard actuator—meaning no outside stimulus is needed.
While the microbots are currently controlled by a tether, eventually, an onboard battery and a microcontroller will apply an electric current in the systems.
“When current passes through the gold layer, it creates heat, and we use heat to control the motions of the microbot,” Filipov says. “We drive the initial fold by heating the system, then we unfold by letting it cool down.
“To get something to fold and stay folded, we overheat the system. When we overheat, we can program the fold—change where it comes to rest.”
These capabilities allow microbots to function elastically and plastically—giving them the ability to recover their original shape.
The research appears in Advanced Functional Materials. The Defense Advanced Research Projects Agency and the UM College of Engineering Dean’s Fellowship funded the study.
Source: University of Michigan
