Laser Pulse Stimulates Microscopic Robot into Motion



The robot is just 5 microns thick and 40 microns wide.

Days after the world’s largest humanoid robot being built and operated in Yokohama took its first step; it is time for the microscopic robots to make a moment. Modelled after Gundan, a humanoid robot that stars in anime series, the 60 feet robot attracted more eyes with its single step.

Walking robots are an important improvement and alternative for immovable robots. This kind of robot can be employed in more general environments to do a daily job. Robots with more legs have more stability. Some robots designed with six legs can commute with three legs on the ground and other three on moving making the robot’s centre of mass within the triangle formed by the three legs on the ground.

Whereas, the microscopic robots are also on the fast pace of improvement. Microscopic robots have the ability to travel and explore places where humans can’t enter. These robots are a breakthrough technology for the medical field. The microscopic robots are expected to crawl through the body, passing by the blood vessels, clearing out diseases or delivering drugs. There is a high expectation on microscopic robots since its existence. But what makes it move is the attachment of legs and some technology.


The first walking microscopic robot

A Cornell University collaboration has created the first microscopic robot that can walk with standard electronic signals. The robots at the size of a paramecium are expected to travel through human tissues and blood soon. They provide a template for building even more complex versions that utilize silicon-based intelligence which can be mass-produced.

The collaboration is led by Itai Cohen, professor of physics along with Paul McEuen, the John A. Newman Professor of physical science. Their former postdoctoral researcher Marc Miskin, an assistant professor at the University of Pennsylvania joined hands with them in the creation. The team’s paper was published on August 26, 2020, with the title, ‘Electronically Integrated, Mass-Manufactured, Microscopic Robots.’


Creation of microscopic robot

The microscopic robot is about 5 microns thick (a micron is one-millionth of a meter), 40 microns wide and range from 40 to 70 microns in length. Each bot consists of a simple circuit made from silicon Photovoltaics which essentially functions as the torso and brain and four electrochemical actuators that function as legs.

The robots are high-tech, but operate with low voltage at 200 millivolts and low power of 10 nanowatts, and remain strong and robust for their size. Because of their small size, around 1 million bots fit on a 4-inch silicon wafer. The robots are made with standard lithographic processes which help them fabricate in parallel. The robot brain was made with existing semiconductor technology, making it small and reasonable.


Making and accelerating the robot legs

Creating legs to a microscopic robot is an enormous job as it involves tiny mechanism. The small, electrically activatable actuators are of no use. So the research team has to invent legs with the combination of electronics.

The team constructed a leg using atomic layer deposition and lithography. The legs were a strip of platinum only a few dozen atomic thick, capped on one side by a thin layer of inert titanium. By applying a positive electronic charge to the platinum, negatively charged ions absorb onto the exposed surface from the surrounding solution to neutralize the charge. The platinum expansion due to ions force makes the strip bend bringing moment. The gaps between the panels act like knee and ankle, allowing the leg to bend in a controlled manner.

The moment is made when laser pulses are flashed at different photovotalics, each with a separate set of charged legs. By toggling the laser back and forth between the front and back photovotalics, the robot walks.

However, the robots are not fast at the moment. The innovation is considered as a standard microchip fabrication that opens the door for a wide range of chances to the microscopic robots that are fast, smart and mass-producible.

The researchers are now exploring ways to enrich the robot with more complicated electronics and onboard computation. These improvements could one day result in swarms of microscopic robots crawling through and restructuring materials or suturing blood vessels. It could even travel to the human brain soon.