Scientists from Imperial College London have demonstrated what they say is a highly efficient method for wirelessly transferring power to a drone while it is airborne.
In theory, according to the researchers, the breakthrough could allow drones to stay in the air indefinitely by hovering over a source to recharge.
The technology uses inductive coupling, a concept initially demonstrated by inventor Nikola Tesla over 100 years ago. Using electronics, two copper coils are tuned into one another, which enables the wireless exchange of power at a certain frequency. Scientists have been experimenting with this technology for decades but have not yet been able to wirelessly power flying technology, according to the college.
Now, the researchers have removed the battery from an off-the-shelf quadcopter and demonstrated that they can wirelessly transfer power to it via inductive coupling.
The scientists bought the mini drone (measuring 12 centimeters in diameter), altered its electronics and removed its battery. They then made a copper foil ring, which is a receiving antenna that encircles the aircraft’s casing. On the ground, a transmitter device made out of a circuit board is connected to the electronics and a power source – creating a magnetic field.
The drone’s electronics are tuned or calibrated at the frequency of the magnetic field. When it flies into the magnetic field, an alternating current voltage is induced in the receiving antenna, and the drone’s electronics convert it efficiently into a direct current voltage to power it, the college explains.
The technology is still in its experimental stage: Currently, the drone can fly only 10 centimeters above the magnetic field transmission source. However, the team estimates they are one year away from a commercially available product.
“Imagine using a drone to wirelessly transmit power to sensors on things such as bridges to monitor their structural integrity,” says Paul Mitcheson, a professor at the Imperial College of London’s Department of Electrical and Electronic Engineering. “This would cut out humans having to reach these difficult-to-access places to recharge them.
“Another application could include implantable miniature diagnostic medical devices, wirelessly powered from a source external to the body. This could enable new types of medical implants to be safely recharged and reduce the battery size to make these implants less invasive.”
Photo courtesy of Imperial College London