A robot helper ushers you to your stadium seat, while artificial meteorites streak across the sky. This is the crazy reality that the 2020 Tokyo Olympics Committee wants to bring to life.
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.