A working nanosized robot requires a host of skills, from complex electronic loops and photovoltaics to sensors and antennas. Also, to move the robot, it should be able to bend.
Cornell engineers have built micron-sized shape memory actuators that facilitate atomically flat two-dimensional materials to overlap themselves into 3D designs. All they need is an instantaneous jolt of voltage. And once the material is bent, it maintains its shape — even after the voltage is removed.
For an exhibition, the team built what is possibly the world’s smallest self-folding origami bird. The research paper “Micrometer-sized electrically programmable shape memory actuators for low-power micro-robotics,” was featured on the cover of Science Robotics. Researcher Qingkun Liu is the paper’s lead author.
The project is directed by Paul McEuen, Professor of Physical Science, and Itai Cohen, professor of physics. McEuen and Cohen’s open-ended collaboration has so far produced nanoscale machines and components, each seemingly quicker, more intelligent, and elegant than the previous.
“We desire to create robots that have brains on board but are microscopic. It means you require accessories that are operated by corresponding metal-oxide-semiconductor (CMOS) transistors, primarily a computer chip on a robot that’s 100 microns on a side,” Cohen said.
Assume a thousand fabricated microscopic robots freeing from a wafer that crawl free, go about their tasks, and wrap themselves into shape, even compiling into more complex structures. That’s the vision.
“The difficult section is getting the materials that react to the CMOS circuits,” Cohen said. “And this is what Qingkun and his co-workers have done with this shape memory actuator that you can operate with voltage and make it hold a bent shape.”
The robots fold themselves fast, within 100 milliseconds. They can also flatten and refold themselves a million times. And they just require a single volt to be powered to live.
The team has already registered a record for creating the smallest robot in Guinness World Records. Now, they are expecting to seize another record with a unique world’s smallest self-folding origami bird that is only 60 microns wide.
The team is currently trying to combine their shape memory actuators with circuits to create walking robots with foldable legs as well as sheet-like robots that move by moving ahead. These modifications may guide to nano-Roomba-type robots that can clean the bacterial germs from human tissue, robotic surgical instruments that are ten times smaller than current devices, and micro-factories that can transform manufacturing, according to Cohen.
Assistance was provided by the National Science Foundation, the Cornell Center for Materials Research, the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory, the Kavli Institute at Cornell for Nanoscale Science, and the Air Force Office of Scientific Research.
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Qingkun Liu, Wei Wang, Michael F. Reynolds, Michael C. Cao, Marc Z. Miskin, Tomas A. Arias, David A. Muller, Paul L. McEuen, Itai Cohen. Micrometer-sized electrically programmable shape-memory actuators for low-power micro-robotics. Science Robotics, 2021; 6 (52): eabe6663 DOI: 10.1126/scirobotics.abe6663