On a recent Sunday, in front of a small crowd of spectators in an abandoned indoor shopping mall in South Central Los Angeles, four young men donned goggles and prepared to race their drones. Seated in front of a promotional banner for the incipient
Robots clean rivers and sort waste, monitor ecosystems, and inspect renewable-energy infrastructure. But even the greenest robot has an environmental footprint.
EPFL engineers have designed acoustic cavities that convert sound waves into thrust, propelling small robots and ultralight aerial vehicles without on-board actuators or electronics.