Virginia Tech testing impact and dangers of drones hitting people

BLACKSBURG, Va. (WDBJ7) With companies set to begin delivery by drones soon, some are concerned about the flying machines hitting people on the street.

Virginia Tech is trying to solve that problem.

A team is using a dummy with sensors in the head and neck and flying drones into it.

By testing numerous drones, the team can know how which designs will cause more serious injury.

The contact sounds bad in the video of testing the team did. But how dangerous can a shot by a drone really be to people?

Stefan Duma, an Engineering Professor at Virginia Tech answered, "The study that we just did at Virginia Tech really illustrated that there's a huge difference as small drones and large drones can go from no injury to near fatal injury risk. So there's a lot of work that has yet to be done."

The team used three commercially available aircraft in the testing, with masses ranging from 1.2 kilograms to 11 kilograms

In general, the injury risk increased with aircraft mass. For example, in drop tests with the smallest drone, the risk of severe neck injury was less than 10 percent; for the largest aircraft, the median risk rose to 70 percent.

While it looks terrible to get hit in the face, the recent study, in fact, found it was worse if the drone fell out of the sky and landed on top of a person's head.

During impacts in which the aircraft was deflected away from the body — by a protruding rotor arm, for example — the force and resulting injury risk were reduced. Aircraft features specifically designed to redirect its center of mass in the event of an impact could make severe injuries less likely.

The data showed that injury risk was also reduced when the aircraft deformed upon impact or when pieces broke off. Those deformations and fractures absorb some of the energy of the crash and offer another route for risk mitigation.

“If you reduce the energy that’s able to be transferred to be head, you reduce the injury risk,” said Eamon Campolettano, a doctoral student from Hicksville, New York, and the paper’s first author. “The overarching goal for manufacturers should be to limit energy transfer.”

So what is the best design to do the least damage?

"The biggest thing is decrease the mass and add some padding, and you're seeing that in some of these more advanced concepts where it's not just about the drone, but it's taking into account of that in a very similar that your car is designed," Duma said,

But Virginia Tech can test any drone to determine it's potential danger.

That includes backup options if an engine dies in the drone.

The university is already working with companies to get delivery drones in the air and approved by the Federal Aviation Administration.

"What we want to do at Virginia Tech is help the companies be able to deliver product," Duma explained. "In order to do that, they have to be cleared by the FAA. Our research is part of that safety case that allows them to get clearance from the FAA to deliver to your home."

Without robust experimental data on these topics, Federal Aviation Administration (FAA) regulations currently prohibit UAS operations over people. (Operators can apply for a waiver, but the FAA has granted only three, all extremely limited in scope.)

“There’s a tremendous demand for more research in this area,” said Mark Blanks, the director of the Virginia Tech Mid-Atlantic Aviation Partnership. “The first step was to establish a baseline for how to perform these tests. Now we’re doing a lot of work with individual companies, looking at specific air frames and potential mitigations.”

“The big question right now is, what is the acceptable level of safety?” said Blanks, who also chairs an industry standards subcommittee developing recommendations for safe operations over people. “How much proof does the FAA need before they say, ‘Yes, that’s okay’? Once those standards are in place, we’re going to see huge expansion in the industry.”

Duma went onto say, in a best case scenario there could be delivery drones filling the skies in about 18 months to two years.

To read the study published by the team, click here.

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