EPFL researchers develop 3D-printed acoustic resonators for micro-robot propulsion

Researchers at EPFL's MicroBioRobotic Systems Laboratory have developed 3D-printed microstructures capable of converting sound directly into directed movement. Utilizing the principle of Helmholtz resonance, these resonators use air oscillation within hollow cavities to generate thrust without the need for motors, gears, or magnetic fields.

The resonators, which can be constructed from plastics, polymers, or glass, function by creating an asymmetric airflow when struck by specific sound frequencies. In centimeter-scale applications, researchers integrated up to three resonators into small boats, allowing them to be steered and automated by switching speaker frequencies.

For even smaller applications, the team utilized 3D nano-printing to create ‘Microfliers.’ These 150-microgram models contain microscopic cavities that respond to ultrasound to generate upward thrust.