Researchers at the University of Michigan and the University of Pennsylvania have developed what they describe as the world’s smallest fully programmable, autonomous robots. The microscale devices, measuring approximately 0.2 by 0.3 by 0.05 millimeters, are capable of sensing their environment, processing information and carrying out programmed tasks. The findings are detailed in two peer-reviewed papers published in Science Robotics and the Proceedings of the National Academy of Sciences.
Each robot is powered and programmed by light pulses and operates at a cost of about one cent per unit. The devices can function independently for extended periods, responding to temperature changes and navigating through liquid environments. Their propulsion mechanism relies on generating electrical fields that move ions in the surrounding fluid, which in turn displace water molecules to propel the robots.
The robots integrate computing components developed at the University of Michigan, based on previous work in sub-millimeter-scale computing. The onboard computer operates on just 75 nanowatts of power, which is significantly lower than that of most small electronic devices. To accommodate the limited energy and memory capacity, the researchers condensed traditional control instructions into single specialized commands.
The prototype robots include temperature sensors that can detect changes within one-third of a degree Celsius. They can transmit this information through programmed motion, similar to the signaling behavior of honeybees. The researchers suggest that such robots could be applied in medical and industrial contexts, such as monitoring cellular health or assisting in the assembly of microscale systems.
The project received support from the National Science Foundation, the University of Pennsylvania Office of the President, the Air Force Office of Scientific Research, the Army Research Office, the Packard Foundation, the Sloan Foundation and Fujitsu Semiconductors. Co-first authors of the studies are Maya Lassiter of the University of Pennsylvania and Jungho Lee of the University of Michigan.
Photo: University of Michigan/Katherine Mcalpine
