Danish company, Valhalla Drone Solutions, a group of seven engineers from the University of Southern Denmark in Odense has developed a prototype Lego Mindstorms robot that automatically switches a quadrotor’s battery pack.
When the quadrotor lands, it’s positioned by a belt, an assembly pops out, and the old battery is lowered out of the quadrotor. That battery is placed into a rotating disk that spins to position a fresh battery, which is then placed into the quad.
One role envisioned for the product is resupplying agricultural UAS.
Source: YouTube