Penn and Michigan Researchers Create World’s Smallest Programmable Robots
Microscopic machines,costing just pennies to produce,represent a monumental leap in robotics and could revolutionize fields from medicine to manufacturing.
Researchers at the University of Pennsylvania and the University of Michigan have achieved a groundbreaking feat: the creation of the smallest fully programmable, autonomous robots ever developed. These microscopic machines, barely visible without magnification, possess the ability to swim through liquids, sense their surroundings, respond independently, and operate for months on end – all at a production cost of approximately one penny each.
A new Scale for Robotics
Each robot measures a mere 200 by 300 by 50 micrometers, substantially smaller than a grain of salt. This diminutive size allows them to function at the same scale as many living microorganisms, opening up possibilities for targeted medical interventions and precision manufacturing. “We’ve made autonomous robots 10,000 times smaller,” explains Marc Miskin, Assistant Professor in Electrical and Systems Engineering at Penn engineering and the papers’ senior author. “That opens up an entirely new scale for programmable robots.” The research, detailed in Science Robotics and Proceedings of the National Academy of Sciences (PNAS), marks a departure from previous attempts at miniaturization, as these robots operate without the need for wires, magnetic fields, or external controls.
Overcoming Decades-Old Challenges
The pursuit of truly self-reliant robots at this scale has been a long-standing challenge in the field. while electronics have consistently shrunk over the decades, robotics has lagged behind. According to Miskin, achieving independence in robots smaller than one millimeter has remained “an unsolved challenge” for approximately 40 years. The core difficulty lies in the shift in physics at microscopic scales. At everyday sizes, forces like gravity and inertia dominate, but at the microscale, surface-related forces – drag and viscosity – become overwhelmingly powerful, making conventional robotic designs impractical. “If you’re small enough,pushing on water is like pushing through tar,” Miskin notes.
Conventional designs, relying on small arms or legs, are prone to breakage and arduous to manufacture. “Very tiny legs and arms are easy to break,” Miskin explains. “They’re also very hard to build.”
A Novel Approach to Microscopic Movement
To circumvent these limitations,the research team developed a wholly new method of locomotion. Instead of mimicking larger-scale movement,the robots generate an electrical field that gently propels charged particles within the surrounding liquid. This movement of ions drags nearby water molecules, effectively creating motion around the robot. “It’s as if the robot is in a moving river,” Miskin describes, “but the robot is also causing the river to move.” By modulating this electrical field, the robots can navigate complex paths, change direction, and even coordinate movements in groups, resembling schools of fish. they can achieve speeds of up to one body length per second.
This electrode-based swimming method, devoid of moving parts, contributes to the robots’ remarkable durability. They can be repeatedly transferred between samples using a micropipette without sustaining damage.Powered by light from an LED, these robots can maintain continuous operation for months.
Packing Intelligence into a Tiny Package
True autonomy demands more than just movement; it requires environmental sensing, decision-making capabilities, and self-powering. Integrating all these components onto a chip measuring only a fraction of a millimeter presented a meaningful hurdle. This challenge was addressed by David Blaauw’s team at the University of Michigan,renowned for creating the world’s smallest computer.
The collaboration between Blaauw and Miskin, sparked by a meeting at a Defense Advanced research Projects Agency (DARPA) presentation five years ago, proved pivotal. “We saw that Penn Engineering’s propulsion system and our tiny electronic computers where just m
