Robots digging deep underground, finding new depths

Robots are being used in oil and gas operations to dig underground, which is often undulating and challenging. Companies are finding innovative ways to overcome the problem.

By Tanya M. Anandan March 23, 2021

Back on land, small robotic crawlers repair gas mains below city streets, and snake robots are the eyes into the recesses of oil and gas operations out of reach to humans. Sarcos Robotics’ Guardian S robot maneuvers into tight spaces and explores hard-to-reach places. It tackles rough, uneven terrain and even defies gravity. This snake-like ROV is designed to inspect areas where humans can’t or shouldn’t go.

The Guardian S robot is used for pre-commissioning inspections of oil and gas assets, where it can efficiently and easily look for everything from debris to structural integrity issues. Additional sensors can be added, including different types of gas sensing, radiation detection, and other environmental-related and situational-awareness sensors.

The snake robot can be teleoperated from miles away and reliably traverse challenging terrain including stairs, culverts, pipes, tanks and even climb ferromagnetic vertical surfaces without a tether. A lithium-ion battery provides power. The robot is small, less than 4 feet long, portable and lightweight.

“Our operators will sometimes just sling it over their shoulder and carry it to whatever location they need to use it. Confined space inspection is one of the hallmarks of this machine. It can go through an opening as small as 8 inches in diameter,” said Ben Wolff, chairman and CEO of Sarcos Robotics.

Mechatronic trailblazers

Headquartered in Salt Lake City, Sarcos spun out of the University of Utah in the early ‘80s with the first electrically actuated prosthetic arm. It became a bestseller around the world.

“This experience gave our team intimate knowledge of how humans could interface with machines,” Wolff said. “That was the beginning of our foray into microelectromechanical systems and the ability to work in tandem with human operators.”

That early knowledge in prosthetics led the company to work on robotic arms and humanoid robots. Sarcos had an entire division that made advanced humanoid robots and dinosaurs for well-known theme parks.

In 2007, Raytheon acquired the business and focused the robotics division solely on U.S. military applications. In 2015, Sarcos emerged from Raytheon as an independent consortium and turned its focus from R&D and custom development to a robotics product company. The Guardian series of products, including the snake robot and a first-of-its-kind battery-powered full-body exoskeleton, evolved from work at Raytheon with the U.S. Defense Advanced Research Projects Agency (DARPA).

Today, Sarcos is an employee majority-owned small business with prominent investors, including Caterpillar, GE Ventures, Microsoft and Schlumberger. Whether you’re wearing or teleoperating a Sarcos product, Wolff said it’s about human augmentation. Human safety is a key driver.

“Our mission statement is to save lives and prevent injury while increasing productivity. Where technology sits today, there’s no reason for people to be getting injured at the rates that they do anymore.”

He says their most recent application with Guardian S was checking for debris inside an LNG (liquefied natural gas) pipeline before it was commissioned. The robot is also routinely used to perform vertical inspections of boilers in power-gen plants and other tasks ancillary to oil and gas production.

“The robot has enough traction to be able to pull cabling through confined spaces, so it’s both an inspection tool and a work tool to get into hard-to-reach places,” Wolff said, noting one caveat. “The Guardian S robot consists of electronic components, motors and transmissions, so it’s not an intrinsically safe machine. It’s not designed to work in an area with a high concentration of combustible gases.”

The system makes use of digital twin technology. Sensors tell you what configuration the robot is in, what kind of terrain it’s sensing and whether it’s responding properly. The Guardian S operator control unit (OCU) is a rugged tablet with controls that allow you to wirelessly manage the machine at distance, view the digital twin and see what the robot sees with its 4K cameras.

“The digital twin is an exact replica of the way the machine is performing, so it allows you to understand the context of what you’re seeing through the cameras and whether the machine itself is responding the way you’re expecting it to,” Wolff said.

The snake robot sells directly to customers, or to distribution partners that make the systems available for short- or long-term rentals or lease. Customers include oil and gas, power-gen and general industrial manufacturing companies where areas need to be inspected in the least invasive way possible.

Wearable robots for heavy lifting

Sarcos’ exoskeleton, Guardian XO, also could help oil and gas workers with some of the tougher jobs.

“When you look at O&G and how companies operate on a daily basis, there are a lot of commonalities with other industries,” Wolff said. “Our customers in oil and gas have warehousing and logistics applications, manufacturing and kitting operations, and general construction operations. So whether it’s moving heavy components around, or manipulating relatively large components to get them shipped out, we’ve designed the XO to address all of those different types of applications across a variety of industries. O&G is no exception.”

The Guardian XO wearable robot is capable of repeatedly lifting and supporting up to 200 pounds. According to the company, it doesn’t matter what your innate lifting ability is, the machine will compensate. It can be donned and doffed in 30 seconds, and requires limited training to become proficient in its use.

“Whether you are young or old, big or small, you’re able to lift 200 pounds without stress or strain on the body,” Wolff said. “In rig up and rig down, when you think of things that humans are doing today to assemble the piping to go downhole, that is an opportunity where we think we can add significant value by taking the load off of the human, particularly in an industry where hiring has been a challenge.”

Robotic cladding in the sour oil patch

As oil gets harder to find, the industry needs to dig deeper. As they go deeper, they run into crude oil that contains more impurities. Crude oil with higher sulfur impurities is considered “sour.” Sour oil wells put more stress on the infrastructure and equipment, and the workers responsible for maintaining the machinery.

Right now, the number of active offshore oil rigs is in a slump, but technology marches on. At ARC Specialties in Houston, they thrive on developing solutions for industry’s problems.

“The level of activity in the oil patch is directly proportional to the price of oil. So when it’s up at $100 or something a barrel, then people are all of the sudden motivated to try to get the oil that’s hard to get,” said Dan Allford, ARC’s founder and president. “That requires our technology.”

Pipes and valves that will come in contact with sour oil need to have the inner surfaces coated with a low-iron nickel base alloy to avoid catastrophic hydrogen-induced cracking failures. But these subsea blocks are huge chunks of steel, 3 x 4 x 6 foot in some cases, and they are riddled with holes to support all sorts of passageways and valves. Yet every internal surface and cavity must be cladded with the coating. That’s where ARC’s weld expertise and persistence pays off.

ARC developed a turnkey robotic welding system called the ARC-5 Infinity. This Infinite Rotation Robotic Cladding System uses a six-axis industrial robot equipped with a 7th axis, ARC’s infinite rotation head. It rotates the welding torch 360 degrees continuously so you can clad a complex internal bore along any axis without any part rotation.

“It makes no sense to rotate a 20,000-pound part when you could rotate a 20-pound torch,” Allford said. “That’s what the robot does.”

These parts have multiple intersections where different cylindrical-shaped cavities meet. Imagine trying to weld all those intersections, and they may be 3 or 4 feet down a 2-inch diameter hole. And the entire part is preheated to at least 400 °F.

“There’s no way a human could do it,” Allford said. “That’s why we’re selling these systems into India and places where they have very low labor costs. It doesn’t matter how low your labor cost is if a human can’t reach 4 feet down a 2-inch hole in a hot part.”

The complexities don’t stop there. All of the surfaces require two thin layers of coating. The second layer, which touches the oil, must have less than 5% iron to avoid hydrogen-induced cracking.

“Every surface has to be done twice. One, to minimize the dilution, and the second, to have some redundancy,” Allford said. “Without this process, you have catastrophic failure in no time at all. Hydrogen embrittlement is an insidious thing.”

Infinite flexibility for large, complex parts

A process of gas tungsten arc welding with hot wire (GTAW/HW) produces the weld overlay. To offset the low productivity of the TIG torch, ARC runs hot wire to increase deposition and reduce dilution. Deposition rates are up to 8 pounds an hour.

Adding to the complexity of the process, you don’t want to break the arc. Because every arc stop and start has a higher potential for defects. This is where the system’s infinite rotation head, or 7th axis, is critical.

“A robot alone can’t do it, because it can only rotate its last axis about two revolutions before you have to stop the torch, unwind it in the other direction and then start again. But we’re making hundreds to thousands of revolutions.”

A robot offers absolute flexibility in motion control, but it’s ARC’s proprietary programming software that brings the magic.

“We don’t write a single line of robot code,” Allford said. “We’re just streaming commands to the robot like you do on a CNC machine. We’re actually generating all those trajectories in our ARC-5 controller and then we tell the robot what to do. We’re streaming motion commands directly to the FANUC robot every few milliseconds.”

The system doesn’t use the robot teach pendant at all. ARC uses their own optimized teach pendant to control all seven axes. All the operator has to do is teach four horizontal points and the software does the rest.

“You teach four points and you get 200. We were able to optimize the software to make it very user-friendly,” Allford said.

As subsea components become more and more complex, Allford said the ARC-5 Infinity system will become essential.

“We just want to stay ahead of the curve. The oil industry is dynamic like that. We don’t even have the technology to handle the ultra-high temperatures and pressures of the oil reserves that we’re discovering. But the oil industry always finds a way.”

Tanya M. Anandan is contributing editor for the Robotic Industries Association (RIA) and Robotics Online. RIA is a not-for-profit trade association dedicated to improving the regional, national, and global competitiveness of the North American manufacturing and service sectors through robotics and related automation. This article originally appeared on the RIA website. The RIA is a part of the Association for Advancing Automation (A3), a CFE Media content partner.

Original content can be found at

Author Bio: Contributing editor, Association for Advancing Automation (A3).