Robotics has been pursuing the same obsession for decades: reducing the size of machines without emptying them of intelligence. Until now, that goal had a physical limit that was difficult to cross. Above a certain threshold, making a smaller robot meant making several compromises. That just changed. A team of researchers has shown that It is possible to build an autonomous robot so tiny that it can barely be seen, but still capable of perceiving its environment, processing information, and responding without outside intervention.
The development comes from researchers at the University of Pennsylvania and the University of Michigan, who have built what the team describes as the autonomous programmable robot smallest achieved so far. The device is designed to operate submerged in a fluid, and in that environment it can move and operate. The scientific article describes a body measuring approximately 210 by 340 micrometers and 50 micrometers thick. Its scale is so small that it can rest on the ridge of a fingerprint and is almost invisible to the naked eye.
A complete robot on a microscopic scale. The difference compared to previous attempts is not only in the miniaturization, but in what this device theoretically manages to integrate. According to the researchers, the microrobot incorporates computing, memory, sensors, communication and locomotion systems within a single autonomous platform. Until now, these systems often relied on external equipment to process information or make decisions. In this case, the robot can execute digitally defined algorithms and modify its behavior based on what is happening around it.
The main obstacle to getting here has not been conceptual, but physical. At micrometer scales, the rules change: gravity and inertia lose weight, and forces such as viscosity and drag dominate. In that environment, moving through a fluid is more like moving through thick material than swimming in water. Added to this difficulty is an even more severe restriction, energy. With power budgets around 100 nanowatts, integrating propulsion and computing at the same time had been, until now, an almost impossible compromise.
Electronics designed to survive on almost no power. The solution involved rethinking the robot’s electronic architecture from scratch. The team worked with a 55 nanometer CMOS process and used subthreshold digital logic to keep consumption within a budget close to 100 nanowatts. In that space they managed to integrate photovoltaic cells for power, temperature sensors, control circuits for the actuators, an optical receiver for programming and communication, as well as a processor with memory.
Locomotion is one of the most unique aspects of design. Instead of motors or appendages, the microrobot uses electric fields to induce currents in the fluid around it, moving without moving parts that could break. Its creators describe it as a system in which the robot generates its own “river” to move forward. That same minimalist logic extends to communication. The measurements you make, such as temperature, are encoded into motion sequences, a simple but effective method at this scale.
Tiny robots that act together. Beyond individual behavior, the team has shown that these microrobots can synchronize and operate in groups. According to the researchers, several devices are capable of coordinating their movements and forming collective patterns comparable to schools of fish. This approach opens the door to distributed tasks, in which each unit contributes local information or action. In theory, these groups could continue to operate autonomously for months if kept charged with LED light on their solar cells, although available memory limits the complexity of programmable behaviors for now.
With this platform, researchers propose a path toward more general-purpose microrobots, capable of executing tasks in difficult environments without constant supervision. On the horizon are applications that today are closer to the laboratory than to the real world, for example in biomedicine, where devices of this type could operate on body fluids. The team itself insists that this is just a first step. The advance opens a technical base, but the jump to practical uses will depend on increasing performance.
Images | University of Pennsylvania and the University of Michigan
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