A 50-pound flying robot can be lethal. As drones swarm the U.S., regulators need convincing before they give Amazon, Google, and others permission for expanded use.
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.