The purpose of a Nimbus Labs project is to develop a wireless power transfer system that enables unmanned areal vehicles (UAVs) to provide power to, and recharge batteries of wireless sensors and other electronics far removed from the electric grid. We do this using wireless power transfer through the use of strongly coupled resonances. We have designed and built a custom power transfer and receiving system that is optimized for use on UAVs. We are investigating systems and control algorithms to optimize the power transfer from the UAV to the remote sensor node. In addition, we are investigating energy usage algorithms to optimize the use of the power in networks of sensors that are able to be recharged wirelessly from UAVs.
When everything works perfectly, the quadrotor can wirelessly transfer about 5.5 watts of power with an efficiency of 35 percent, which is easily enough to power a light.
IEEE Spectrum – The type of wireless power that these quadrotors are beaming out is based on what’s called “strongly coupled magnetic resonances.” Basically, you’ve got two coils of wire: one on the quadrotor, and one on whatever you want to power or charge (we’ll call this the receiver). The quadrotor drives a current in its coil, which generates an oscillating magnetic field. When the quadrotor gets close enough to the receiver, the receiver’s coil starts to resonate with the magnetic field transmitted by the quadrotor. That resonance induces a voltage in the coil, which the receiver can use to power its electronics or charge its battery.
As far as applications go, the researchers suggest that this kind of system would be great for “highway messaging systems, ecological sensors located in forests, or sensors shallowly embedded underground or in concrete.” UAVs would act as mobile power stations, zipping around and delivering power to sensors when necessary. Rumor has it that CyPhy Works (the stealthy startup run by iRobot co-founder Helen Greiner) is developing UAVs for infrastructure inspection, and it seems like some wireless sensor charging capability would fit right in with that sort of thing.