These 3D-Printed Vibration-Powered Robots are the Size of the World's Smallest Ant

The micro robots could one day be used to repair injuries inside the human body.

Georgia Tech researchers have engineered a new type of tiny vibration-powered 3D-printed robots that might work together to move materials or even, one day, fix injuries inside the human body. Only two millimeters long, approximately the size of the world's smallest ant, the bots can cover four times their own length in a second.

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"We are working to make the technology robust, and we have a lot of potential applications in mind," said Azadeh Ansari, an assistant professor in the School of Electrical and Computer Engineering at the Georgia Institute of Technology. "We are working at the intersection of mechanics, electronics, biology and physics. It's a very rich area and there's a lot of room for multidisciplinary concepts."

A piezoelectric actuator 

The tiny bots consist of a piezoelectric actuator glued onto a polymer body that is 3D-printed using two-photon polymerization lithography (TPP), a technique that polymerizes a monomer resin material. Since no batteries are small enough to fit onto the bot, the actuator generates vibration through external sources. 

"As the micro-bristle-bots move up and down, the vertical motion is translated into a directional movement by optimizing the design of the legs, which look like bristles," explained Ansari. "The legs of the micro-robot are designed with specific angles that allow them to bend and move in one direction in resonant response to the vibration." 

Steerable robots

Ansari and her team are now working on adding steering capability to the robots. They aim to achieve this by joining two slightly different micro-bristle-bots together with different vibration frequencies. Then, by varying the frequencies and amplitudes, one could potentially steer the tiny robots.

"Once you have a fully steerable micro-robot, you can imagine doing a lot of interesting things," she said.

Currently, these micro-bristle-bots are believed to be the smallest robots powered by vibration. They are approximately two millimeters in length, 1.8 millimeters wide and 0.8 millimeters thick, and weigh about five milligrams.

Ansari and her team have also created a "playground" in which the researchers can test more of what these robots can do. They are seeking to develop micro-bots that can jump and swim.

"We can look at the collective behavior of ants, for example, and apply what we learn from them to our little robots," she added. "These micro-bristle-bots walk nicely in a laboratory environment, but there is a lot more we will have to do before they can go out into the outside world."

The study is published in the Journal of Micromechanics and Microengineering.

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