Sub UAS Develops Submersible Robots That Can Fly

From marine safety to infrastructure inspection, a hybrid vehicle promises new levels of data collection.


Sub UAS has worked with the U.S. Department of Defense and has plans for commercial applications.
Sub UAS was founded by a Rutgers University professor who has devised propulsion systems that work both in air and underwater, opening new applications for drones.

Last month, the entire world was abuzz when five über-wealthy explorers perished at the bottom of the Atlantic Ocean near the grave of the once “unsinkable ship.” Disturbingly, during the same week, hundreds of war-torn refugees drowned in the Mediterranean, with less news coverage of their plight. The irony of machine versus nature illustrates how tiny humans are in the universe, and that every soul rich or poor is precious. It is with this attitude that many roboticists have been tackling some of the hardest problems, from space exploration and mining in the desert to oceanography and search and rescue.

Following the news of the implosion of the Titan submersible, I reached out to Prof. F. Javier Diez at Rutgers University for comments on the rescue mission and the role of robots. The aerospace academic is also an entrepreneur of a novel drone technology company that can fly and swim autonomously within the same mission.

As Diez explained, his approach could have saved time and money in ascertaining the same unfortunate answer.

“I think we could go down to 12,000 [ft.]. No problem,” Diez said. “So now imagine sending a 20-lb. [robot] down to 12,000 ft. You can do this in a couple of hours. You just throw it overboard, or you fly. You don’t need to bring in a crane, a gigantic ship, and all this very expensive equipment just to do that first look.”

Dr. Diez’s sentiment was validated during the first press conference of U.S. Coast Guard Rear Adm. John Mauger when he cautioned the media of the huge logistical undertaking in moving such large equipment to a remote, hostile, area of the globe.

“We could have been there in a couple of hours,” Diez claimed. “So of course, you know there’s more to it. But I was just saying that long term, I can see how very small robots like ours for search and rescue could be huge.”

“We are doing some work,” he added. “We actually put some proposals with the submarine community. I think this has a huge application because again, these 20-lb. [drones] are something you can deploy from anywhere, anytime.”

Designing propulsion for different environments

In breaking down his invention, the drone CEO elaborated on the epiphany that happened in his lab years earlier by overcoming the conventional wisdom that an uncrewed system that operated in two modalities—marine and air—required two separate propulsion systems.

Diez further noted that two propulsion systems were very inefficient regarding burning energy and functionality. “And this was I would say a mental barrier for a lot of people, and it still is when they see what we put into it,” he said. But first, he had to overcome many industry naysayers.

“I brought this to some folks at NASA, and everyone was saying, 'It’s not going to work,'” he recalled. “And then when you look at what’s behind the propeller design and the motor design, you realize that we cannot be living on an edge. We designed propellers for a very specific condition, which is air.”

However, the innovator challenged the status quo of the aerospace community by asking, “'Can you design propellers and motors for water?' And it turns out that you can.”

Diez deconstructed his lab’s research: “So if you look at the curve for air, and you look at the currents for water, they intersect, and if you do it the right way, you can be efficient in both places. So that was the breakthrough for me to be able to show. And we actually show that you can design propellers that can be efficient in both air and underwater.”

Hybrid vehicle schematic

Click on schematic to enlarge. Source: F. Javier Diez, Rutgers University

Programming for the water-to-air transition

After sharing insights into the design, Diez then explained that the programming of the flight controls was the next hurdle to overcome.

“The next challenge is the transition,” he said. “So we worked very hard from the very beginning on that transition from water. We actually have a patent on this, and it’s really the heart of our technology.”

“I call it dual-plane propulsion. You have two propellers on the top and two propellers on the bottom,” continued Diez. “So when you’re on the surface, the bottom ones are in the water, and the top ones are in the air. So the bottom ones are like when you have a baby and you are pull-swimming. Babies are not very good at swimming, but if you put your hand on their bellies, all of a sudden, they become great swimmers. So think of it as the bottom propellers.”

“When the vehicle is on the surface, the bottom propellers are keeping it very very stable,” the professor asserted. “So now that you have that stability, the top [propellers] can work together to get [the drone] out of the water. So that’s how we accomplish the continuous transition. You can go in and out 100 times.”

Diez’s company, Sub UAS, is not a theoretical concept, but an actual product that is currently deployed by the U.S. military, and looking to expand into commercial markets.

“So we’d been 100% with the Department of Defense,” he said. “They really supported the development of technology.”

Now, Diez said he is itching to expand from a DARPA-funded project to new deployments in the municipal and energy sectors. “We have done a lot of different types of inspections related to ship pylons,” noted the startup founder. “Now, we have [Florida’s] Department of Transportation interested in this technology,” said the startup founder.

“What I realized over the last year or so is that defense has its own speed. You cannot really push it,” Diez added. “There is a specific group now in defense that is encouraging us, but it takes a couple of years.”

Sub UAS hybrid vehicle

The Navigator transitions from surface to aerial operation. Source: Sub UAS

Sub UAS aims for commercial applications

He said he hopes Sub UAS will profitable very soon by opening up the platform for commercial applications.

“Now we’re starting to see the fruits of that [effort],” said Diez. “I can tell you that we got approved in Europe to do offshore wind turbine inspection later this summer.”

However, Diez is most excited by bridge inspections. “We have over half a million bridges in the U.S.A. And like at least 50,000 to 200,000 have something seriously wrong with them,” he observed. “I mean, we’re not doing enough inspections. So having a vehicle like the Navigator that can look at the underwater part of the bridge is huge.”

Diez said he has also been approached by several companies in the energy industry. “And then there are a lot of interesting assets within the oil and gas, but we are discovering this,” he said. “It’s kind of almost like a discovery phase because nobody has ever had the capability of doing air and marine.”

Although many remotely operated vehicles (ROVs) are already inspecting rigs on the ocean surface, and drones are conducting aerial inspections, no one is focused on the “splash zone” where the two meet because they never had dual modality before, claimed Diez.

He expanded on the value proposition of this specific use case: “Nobody gets close to the surface. So they’re saying that that’s a huge application for us.”

In the long term, Diez said he could imagine replacing tethered ROVs altogether as his system is easier and cheaper to deploy.

State of U.S. bridges

Click on image to enlarge. Source: American Society of Civil Engineers

Infrastructure inspections needed

Today, the business model for Sub UAS is on an inspection basis, but over time it will center around data collection, since its system is are the only waterproof aerial drone on the market that can swim.

“We go to the bridge inspectors, and we work with them to simplify their lives, and at the end of the day reduce the risk for the diver,” said Diez. “So they know what we are doing is making their lives easier.”

However, that is only the tip of the iceberg, he said, because “it’s not so much about the hardware or the sensors, but the data that you collect. We think cloud services are huge as it allows you to sort and analyze it anywhere.”

Diez concluded by sharing that his next model will use artificial intelligence to interpret conditions and autonomously planning missions accordingly. Maybe soon, virtual explorers could look at shipwrecks as well from the comfort (and safety) of their couches.

Oliver Mitchell, ffVC

About the author

Oliver Mitchell is a partner at ff Venture Capital. His areas of focus are drones, robotics, and applied AI. Mitchell is also an adjunct professor at Yeshiva University. This column is reposted with permission.

Part submarine, part aircraft, the Naviator is the brainchild of Dr. F. Javier Diez-Garais Associate Professor of Mechanical & Aerospace Engineering at Rutgers University.

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Sub UAS has worked with the U.S. Department of Defense and has plans for commercial applications.

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