Drones are a great tool that can be used for a myriad of applications, including search and rescue operations, job site inspections, and environmental monitoring and conservation. No matter what kind of drone or job function, they all have a single drawback in how long they can operate because of limited battery power. Add to that the batteries weight, and you are limited to the amount of hardware (sensors, cameras, etc.) which can be carried.
Engineers from UC Berkeley’s HiPeRLab have come up with an ingenious solution to keep drones flying and on-station for long periods — Flying batteries. The Midair Hotswap project is meant to use a single large quadrotor, which is outfitted with its own battery and a docking station mounted on its top. When power becomes low, little quadrotors equipped with a single battery dock with the larger drone, where it immediately draws power.
The 1.8-pound host drone has an onboard 2.2Ah lithium-polymer battery that provides the drone about 12 minutes of power, while the smaller 0.7-pound flying batteries feature an 0.8Ah built-in battery, plus another 1.5Ah battery as cargo. Utilizing the airborne batteries pushed the larger drone’s flight time from 12-minutes to nearly an hour, making it a significant improvement.
The secret to docking with the larger drone lies in the docking tray, which features embedded electrical contacts in each of the four corners. The smaller drones position their payload about 30 centimeters above the docking tray, where it slowly descends to three centimeters to align the contacts, and then docks, providing instant power.
The entire process happens in a motion-capture environment indoors, getting the process to work outside is something the engineers are currently trying to overcome using onboard sensors. They are also looking at ways to use just a single battery for the smaller drones to reduce their mass.