These tiny bots are about 2 millimeters long which can cover four times their own length within a second. Researchers are confident that swarms of these bots can be used to detect environmental changes, move materials, or even repair injuries inside the human body in the future.
These ant-size bots are made of a piezoelectric actuator glued onto a polymer body which is 3D-printed using two-photon polymerization lithography (TPP). The actuator generates vibration and is powered externally because no batteries are small enough to fit onto the bot. The vibrations can also come from a piezoelectric shaker beneath the surface on which the robots move, from an ultrasound or sonar source, or even from a tiny acoustic speaker.
The vibrations move the legs of the bot up and down which pushes it forward. Each robot can be designed to respond to different vibration frequencies depending on leg size, diameter, design, and overall geometry. The amplitude of the vibration controls the speed at which the micro-bots move. The springy legs are designed in specific angles which allow these microbots to bend and move in one direction with the help of resonant response of the vibration.
Ansari and the 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.
The micro-bot fabrication was performed at the Georgia Tech Institute for Electronics and Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the National Science Foundation through grant ECCS-1542173.
CITATION: DeaGyu Kim, Zhijian Hao, Jun Ueda, and Azadeh Ansari, “A 5mg micro-bristle-bot fabricated by two-photon lithography” (Journal of Micromechanics and Microengineering, 2019). https://doi.org/10.1088/1361-6439/ab309b
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