- According to Itai Cohen, professor of physics in the College of Arts and Sciences, before, they had to manipulate these wires to get any response from the robot.
- But with their recent study, it is like taking the strings off the marionette with the brains on board.
Cornell researchers implanted electronic “brains” in solar-powered robots measuring 100 to 250 micrometers in size, allowing the tiny robots to walk autonomously without being controlled externally. Robots are about the size of an ant’s head.
Previously, Cornell researchers and others created microscopic machines that can crawl, swim, walk, and fold themselves up. To generate motion, wires carrying electrical current or laser beams focused directly on specific locations on the robots were used. Previously, they had to manipulate these wires to get any response from the robot, according to Itai Cohen, professor of physics at the College of Arts and Sciences. However, their recent study is akin to removing the marionette’s strings while keeping the brains on board.
The breakthrough paves the way for a new generation of microscopic devices capable of tracking bacteria, sniffing out chemicals, restringing pollutants, performing microsurgery, and removing plaque from arteries.
The “brain” in the new robots is a complementary metal-oxide-semiconductor clock circuit containing a thousand transistors and an array of diodes, resistors, and capacitors. The integrated CMOS circuit generates a signal that produces a series of phase-shifted square wave frequencies that, in turn, set the robot’s gait. The legs of the robot are platinum-based actuators. The circuit and the legs are powered by photovoltaics.
The team created three robots to demonstrate the CMOS integration: a two-legged Purcell bot, named in tribute to physicist Edward Purcell, who proposed a similarly simple model to explain the swimming motions of microorganisms, a more complicated six-legged antibot, which was with an alternating tripod gait, like that of an insect; and a four-legged doubt that can vary the speed with which it walks. The robot has chemical detectors to photovoltaic “eyes” that help it to navigate by sensing changes in light.
On September 21, the team’s paper, “Microscopic Robots with Onboard Digital Control,” was published in Science Robotics. Cohen’s lab, Alyosha Molnar, associate professor of electrical and computer engineering at Cornell Engineering, and Paul McEuen, the John A. Newman Professor of Physical Science, collaborated on the project (A&S).