The robots might one day rise up and take over, but a Palo Alto startup called Knightscope has developed a fleet of crime-fighting machinery it hopes to keep..
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.