Drones are great and all, but battery life remains a big problem — particularly when it comes to small quadcopters.
That may be acceptable when you’re using one as a toy, but as professional use-cases open up, quadcopters offering just seven minutes of flight time per charge are a major barrier.That’s where researchers from Imperial College London come into play. They’ve created a highly-efficient method for wirelessly transferring power to a drone while it’s in flight.
“What this means is that rather than having to have its battery switched out, a drone could just return to a base unit and hover over a charging station to pick up the necessary charge,” Dr. Samer Aldhaher, a member of the university’s Department of Electrical and Electronic Engineering, told Digital Trends. “It removes a very time-consuming step, and means that missions can be carried out with minimal interruption.”
To demonstrate the technology, the researchers involved with the project purchased an off-the-shelf quadcopter and then made various modifications, including the removal of its battery.
“We removed the battery just to show we weren’t cheating in any way,” Dr. Aldhaher said.
After this, they constructed a copper foil ring that acts as a receiving antenna for the drone. On the ground, a transmitter is connected to electronics and a power source to create a magnetic field. The drone’s electronics are then tuned to the frequency of this field. When the drone flies into the magnetic field, alternating current (AC) voltage is induced in the receiving antenna and converted into direct voltage (DC) aboard the drone to power it.
A drone could theoretically remain airborne indefinitely (although without a battery, the demo can’t leave that field).
“At the moment, we’re able to deliver power over a distance of around 12 cm,” Aldhaher continued. “Because it’s near-field induction power transfer technology, you can’t extend that much further. But if you want to increase the distance — which we very much do — you can make the transmitter larger so as to generate a larger magnetic field to cover a wider area. That would have the effect of increasing the range.”