UC engineers build tethered drones for safety, longer flights

University of Cincinnati Prof. Manish Kumar demonstrates a drone connected to a tether, which could be an electric tether to keep a drone flying safely for a long duration. (Ravenna Rutledge/UC)

Some solid engineering ideas are relatively simple.

Engineers at the University of Cincinnati are developing a semi-autonomous tethered drone that is moored to the ground and can operate more safely and much longer with an electric tether.

“The battery is a big limitation for drone flight time,” said Prof. Manish Kumar at UC’s College of Engineering and Applied Science.The tether could be a thin electric cord, fiber-optic cable or even a kite string. 

Because pulling a tether can destabilize a drone, the UC engineers have developed a semi-autonomous navigation system that lets the drone stabilize itself while in the air.

The nav system uses artificial intelligence based on fuzzy logic that makes decisions based on degrees of truth, not binary true-false decisions. The system is considered more robust because no precise inputs are required.

UC doctoral student Shradda Barawkar said a tethered drone could be used for interplanetary exploration. “You could easily use a tethered drone attached to a rover,” she said.  On Mars, the Ingenuity flying helicopter experienced sudden oscillations during its sixth flight before safely landing. Ingenuity has also completed two more flights, completing its eighth flight on June 21, NASA JPL recently tweeted.

RELATED: Ingenuity Mars copter survives 6th flight glitch, lands safely

Tethered drones can operate with fewer FAA restrictions and operators don’t need a license, training or certification.

After a disaster, a tethered drone could be used for helping reestablish local communications and stay aloft for a long time. Barawkar was inspired to study drones after the devastating Nepal earthquake in 2015, she said in a UC press release.

The quake killed more than 8,800 people.

Researchers said a tethered drone would also allow for secure communication, including a video feed from the drone to a ground station separate from a more public network. A tethered drone on a battlefield could help soldiers see the terrain from a high vantage point.

A key purpose of the tether is to increase safety, Barawkar said, noting that traditional drones fly with remote control or semi-autonomous navigation, with a risk of a crash.

Barawkar, Kumar and Kelly Cohen, interim head of the department, hold a provisional patent for their tethered drone. Kumar demonstrated a tethered drone connected to a pole to show simple maneuvering: