Wirelessly powered drone enables indefinite flight time
A drone capable of being powered by wireless induction, allowing it to stay airborne indefinitely, has been demonstrated by Imperial College London scientists.
The device uses inductive coupling, a concept initially demonstrated by inventor Nikola Tesla over 100 years ago.
Two copper coils are tuned into one another enabling the wireless exchange of power at a certain frequency. Although experiments have been conducted using this technology for decades, this is the first time it has been demonstrated wirelessly powering flying devices.
A retail quadcopter drone, measuring approximately 12 centimetres, was used to prove that the method works. Its electronics were altered to make it compatible with the wireless charger and its battery was removed.
They made a copper foil ring, which is a receiving antenna that encircles the drone’s casing. On the ground, a transmitter device made out of a circuit board is connected to 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 (AC) voltage is induced in the receiving antenna and the drone’s electronics convert it efficiently into a direct current (DC) voltage to power it.
Although the technology is still experimental, currently the drone can only currently fly ten centimetres above the magnetic field transmission source, the team estimates that a commercially available product is only a year away.
When commercialised they believe their breakthrough could have a range of advantages in the development of commercial drone technology and other devices.
The use of small drones for commercial purposes, in surveillance, for reconnaissance missions, and search and rescue operations are rapidly growing. However, the distance that a drone can travel and the duration it can stay in the air is limited by the availability of power and re-charging requirements. Wireless power transfer technology may solve this, say the team.
For example, Amazon is experimenting with drones in the UK to deliver consumer goods and the UK government is even considering deploying drones to monitor the border between Northern Ireland and the Republic of Ireland once the UK leaves the EU following the Brexit vote in June.
Dr Samer Aldhaher, an Imperial College London researcher, said: “There are a number of scenarios where wirelessly transferring power could improve drone technology. One option could see a ground support vehicle being used as a mobile charging station, where drones could hover over it and recharge, never having to leave the air.”
Wirelessly transferring power could have also applications in other areas such as sensors, healthcare devices and further afield, on interplanetary missions.
The university’s Professor Paul Mitcheson said: “Imagine using a drone to wirelessly transmit power to sensors on things such as bridges to monitor their structural integrity. This would cut out humans having to reach these difficult to access places to re-charge 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.
“In the future, we may also be able to use drones to re-charge science equipment on Mars, increasing the lifetime of these billion dollar missions.
“We have already made valuable progress with this technology and now we are looking to take it to the next level.”