With the recent demonstration of a drone-based delivery system by Google, the tech industry’s enthusiasm for the devices seems undimmed — but some issues will be difficult to solve.
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.