SEOUL: South Korean researchers have developed a transport drone flying on multiple flexible rotors that self-correct to stay level in flight and can be used as a `flying shopping cart` to carry goods over uneven terrain such as stairs.

The prototype developed by a Seoul National University of Science and Technology team has a cargo platform mounted on top of a multi-rotor drone and is handled by a person using gentle force to guide the hoveringaircraft.

Members of the team demonstrated the hovering platform with a handle bar much like one on a push shopping cart moving objects up and down stairs and loading boxes on top as it hovered midair and maintained its balance by using a centre of mass estimation algorithm.To move objects over uneven terrain or stairs when a wheeled cart cannot, the drone responds to human control with what the developers call a physical human-robot interaction technique that anticipates human intentions for smooth flight, said Lee Seung-jae, professor of mechanical system design engineering.

But the broader focus of Lee`s team is not on developing a shopping cart to be used over steps, but instead on applications that would use a drone with reliable horizontal stability without pitching and rolling.

`The Palletrone can be more than a flying shopping cart,` he said, referring to the name the team gave the prototype by joining the words pallet, which is the platform for cargo on top, and drone.-Reuters