Engineers at the University of California, Berkeley have developed what they report to be the world’s smallest wireless flying robot capable of controlled flight. The insect-inspired device, which weighs 21 milligrams and measures less than one centimeter in diameter, is described in a study published March 28 in Science Advances.
The robot mimics the flight mechanics of a bumblebee, enabling it to hover, change direction, and strike small targets. The researchers designed the robot with two miniature magnets and a propeller-like structure. When exposed to an external magnetic field, the magnets generate lift by spinning the propeller, allowing the device to achieve flight. The direction and behavior of the robot can be regulated by adjusting the strength and orientation of the magnetic field.
According to the research team, this design addresses a common limitation in small-scale aerial robotics: the difficulty of incorporating an onboard power source and flight control electronics. By eliminating the need for internal components and relying instead on external magnetic control, the engineers were able to reduce the device’s size and weight.
The robot’s passive control system, however, currently restricts its ability to respond to environmental disturbances in real time. Without onboard sensors or feedback mechanisms, the robot is susceptible to losing its trajectory in variable conditions such as wind. Future development aims to incorporate active control systems to enable autonomous adjustments during flight.
The new device is approximately one-third the size of the next smallest robot with similar flight capabilities, which measures 2.8 centimeters in diameter. Potential applications identified by the researchers include artificial pollination and inspection of confined or hard-to-reach environments, such as inside pipes.
The development is part of a broader portfolio of miniature robotic systems being investigated by the research group, including ground-based cockroach-like robots and cooperative micro-robots for potential medical applications. These projects are supported by the Berkeley Sensor and Actuator Center.
The study was led by Liwei Lin, Distinguished Professor of Mechanical Engineering at UC Berkeley, with contributions from graduate researchers Fanping Sui, Wei Yue, Kamyar Behrouzi, Yuan Gao, and Mark Mueller.
Photo credit Adam Lau/UC Berkeley
