Advances in computer processing power, battery life, motion sensors and short range connectivity have seen robots leap from the pages of science fiction novels and the frames of futuristic cartoons into the lives of early adopters.
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.