August 01, 2018
By: Richard Wilkinson
Whether it’s the effort to redefine the kilogram or researching the Harry Potter realm of quantum mechanics where things can somehow be in two or more places at one time, quite a bit of the science carried out at the National Institute of Standards and Technology (NIST) can be hard for the average person on the street to understand or relate to.
But at the Unmanned Aerial System (UAS) Flight and Payload Challenge, which NIST held May 21 to 24, 2018, the question being explored was as simple as can be: Can a vertical-takeoff drone hoist 20 pounds (9 kilograms) of communications equipment into the air and hover in place for two hours? And, by the way, the drone itself can’t weigh more than 35 lb (15.9 kg).
It was, in other words, a matter of schlepping.
“It’s not nano, it’s not quantum,” says mechanical engineer Kamel Saidi about the drone breakthrough being attempted. Saidi was the technical lead for the Flight and Payload Challenge, which was carried out by NIST’s Engineering Laboratory for the Public Safety Communications Research Division (PSCR) in NIST’s Communications Technology Laboratory (CTL). The goal of the challenge was to stimulate improvements in the lifting capability of drones as a means to provide an affordable new way to protect public safety.
Lifting a 20 lb weight for two hours is a bigger deal that one might suspect. For commercially available vertical-takeoff drones, hoisting such a payload even for 20 minutes would be a good performance, says Saidi.
The challenge, therefore, was to do what has never been done before. The grand prize was $50,000. The arena was an airfield south of Fredericksburg, Virginia.
Life or Death
The ultimate purpose of the drone challenge is a matter of life or death.
The scenario proposed to the competitors was this: A person has been reported lost in a mountainous forest, where normal cell phones and first-responder communications devices won’t function. The competitor's drone would need to lift a “cellular network in a box” into the air, where it would enable rescue personnel on the ground to communicate with each other.
This application could also enable communications in other kinds of emergency situations, such as a forest fire in the mountains. Aerial drones (as opposed to hot-air balloons) are ideally suited for this because one can quickly direct a drone to a different location, and a drone can hover in place without being blown around by the wind.
The goal defined
PSCR is now busy carrying out R&D to build the actual communications network box that could someday be lifted into the air in such emergency situations. But the Flight and Payload Challenge was focused on just the lifting capability. During the challenge, the drones were not lifting actual communications gear, but just successively heavier dummy boxes weighing 10, 15 and 20 lb (4.5, 6.8 and 9 kg).
The parameters of the competition were as follows:
- The 35 lb weight limit for each drone was chosen because 55 lb (25 kg) (i.e., the 35 lb drone plus the 20 lb payload) is the weight of the heaviest aerial drone that the Federal Aviation Administration allows to fly without getting specific FAA permission. At the point when such communications-toting drones are commercialized for use by first responders, NIST doesn’t want the first responders to have to get special FAA permission to fly them.
- Each drone was required to fit in a space of 6 by 4 by 3 feet (1.82 by 1.21 by 0.9 meters) when in its packed configuration. The thought behind this is that it would fit in the bed of a pickup truck and be easily deployable by first responders.
- NIST competitively selected 10 finalists based on their initial concepts and provided each with a $20,000 cash prize to build a prototype drone, all within this budgeted cost. Keeping the cost down is intended to allow such drones—if commercialized—to be affordable.
- Scoring was based on how long a drone could hover with each of the three weighted payloads, as well as its ability to maneuver and land.
And then there were three
Scientific progress demands patience and perseverance and often involves taking two steps forward and one step back. That’s the way this challenge rolled out as well. Although 10 drone makers were chosen as finalists to compete for the $50,000 grand prize, those 10 were whittled down to just three. The rest couldn’t get their drones to fly correctly in the allotted time, had accidents resulting in damage that they didn’t have time to repair, or knew that they wouldn’t be able to achieve the goal, says Saidi.
Of the three teams who made it to the field of competition—all of whom were start-up companies—one was set back by U.S. airport security. Officials confiscated some components of its drone because of security concerns. While the team was able to replace parts by buying them from hobby stores, it ultimately determined its drone wouldn’t meet performance and safety standards for the competition.
Of the two other competitors, the winning one—DV8 Tech, of Salina, Kansas—fielded a drone whose onboard gasoline generator periodically recharged onboard batteries, allowing the drone to string together a series of flights totaling an hour and 27 minutes with the 10 lb payload, an hour and 15 minutes with the 15 lb payload, and 40 minutes with the 20 lb payload. This approach was not excluded by the rules and demonstrated how, in the future, two drones working in coordination might be able to achieve longer flight times by working together.
Although its drone hadn’t hoisted any of the payloads for two hours, this team met the criteria to receive the $50,000 grand prize. It did so by scoring at least 270 points (one point being earned for each minute hoisting 10 lb, three points for each minute hoisting 15 lb, and six points for each minute hoisting 20 lb).
The next challenge
“The competition result is promising for the prospect of being able to fly for a long time with a payload,” says Saidi. “Obviously the drones need improvement, and both teams that competed believe they can make the necessary improvements so that their drones fly for much, much longer than they were able to demonstrate. I think it’s a good step in the right direction. That’s why we’re hoping that we might have a second challenge and fly for more than two hours at a time without landing.”
“At the conclusion of a challenge, the question always comes up: What happens next?” says Craig Connelly, PSCR’s prize and challenge specialist.
“Right now, we are collecting information from the contestants, judges, and technical subject-matter experts to assess whether we will launch a second iteration of the challenge,” Connelly says. “It’s clear that the contestant teams and the first responders supporting the challenge are eager to see more drone designs, longer flight times, and other innovative technologies to support specialized flight missions in more challenging scenarios."
Speculating about the future, Terese Manley, PSCR’s open-innovation outreach manager, believes that future improvements in battery technology will be a game-changer for drones designed to hover with communications equipment. “The power density in current batteries is a limitation at this point, just as it is for electric cars,” she says.
Hydrogen fuel cells, which could be lighter than gasoline generators or batteries, also look promising as a future power source for these drones, says Saidi.
Only at NIST
“There’s no way we could’ve done this without Kam [Saidi] and his team at the NIST Robotics Test Facility,” says Connelly. “Their standardized testing and assessment protocols, which they’ve developed over several years, have been instrumental in creating the assessment framework that we used in the Flight and Payload Challenge.”
Congress has tasked NIST’s Communications Technology Laboratory with establishing an R&D program to support the development and deployment of a nationwide public safety broadband communications network, and with advancing a range of public-safety communications capabilities. The Flight and Payload Challenge was funded by the federal government’s 2016 auction of public communications spectrum to broadcasters.
PSCR’s mandate is to stimulate early-stage technology development and to provide the “proof of concept” for new public-safety technologies—such as drones that enable life-saving communication for first responders.
Now that’s something that the average person on the street can relate to.