When the aircraft maintenance crew at Warner Robins Air Force Base called for better safety monitoring when working in fuel tanks, they got a flexible and compliant armband equipped with Bluetooth that monitors compound concentrations. volatile organic compounds (VOCs), oxygen levels, temperature and humidity. The safety device was developed by NextFlex, using an emerging technology called Flexible Hybrid Electronics (FHE), in collaboration with the Materials and Manufacturing Directorate and the 711th Human Performance Wing of the Air Force Research Laboratory.
“It’s a new way to integrate electronics into things,” said Janos Veres, director of engineering at NextFlex, the US institute of manufacturing innovation focused on FHE. “Obviously the main applications are in the defense and aerospace sectors, but this technology will migrate … everywhere.”
Overall, Veres’ prediction is reinforced by the analysis of the FHE market.
“Over the past five years, global printed electronics market revenue has grown rapidly, for a combined annual growth rate of 22%, according to the Prescient & Strategic Intelligence market research report,” Yuepeng Zhang, principal scientist of the materials at Argonne National Laboratory, he said in a webinar on making materials for FHE. “At this rate, overall revenue is projected to increase from $ 36 billion in 2019 to $ 360 billion by 2030.”
In addition to environmental monitoring such as that performed by Warner Robins, there are applications for FHE in aerospace and defense in biomedical assessment, security, communications, energy generation and storage, computing, supply chain management and support. of resources.
It’s easy to see why the aircraft maintenance team at the base prefers its new bracelets over traditional means of monitoring their safety.
“Current methods of monitoring the health and safety of workers in confined spaces rely on bulky atmospheric monitors and continuous visual observation,” according to a story posted on the NextFlex website. “These methods are laborious and imprecise, as they cannot monitor the atmosphere directly around workers or indicate when workers are in a dangerous situation.”
Just like at Warner Robins, the use of FHE on traditional semiconductor integrated circuits is popular because they are flexible, smaller and lighter.
For example, the NextFlex flexible microcontroller weighs 70% less than the Arduino Mini microcontroller board.
In addition to these parameters, FHE also meets the global demand for cheaper and more energy-efficient electronic devices, Zhang said.
Despite the benefits, there are problems to overcome.
“A major concern for the US electronics industry, and defense electronics in particular, is that while significant research and development in electronics takes place nationwide, much of the manufacturing strength for electronic products lies within the country. ‘overseas,’ according to a 2016 report from the Air Force Research Laboratory (AFRL). “This trend towards stronger foreign electronics manufacturing implies that US defense organizations must work actively to ensure the availability of domestic suppliers and improve their ability to meet the demand for increasingly sophisticated defense electronics.”
An AFRL official confirmed that this claim still rings true in 2021.
Globally, the growth of emerging technology is hampered by the need for more materials, processes and machine tools, said Malcolm Thompson, executive director of NextFlex.
In the United States, the manufacturing sector is well positioned in the FHE industry because of its knack for innovation, he said, and the brilliant minds that work there.
“Talent?” Thompson said. “Basically, yes, we have it.”
Part of this talent resides in NextFlex, where engineers used FHE to create a wearable device that can be used in place of a smartcard by Department of Defense (DoD) personnel for secure access to military systems.
Add order to chaos
In an office or other controlled environment, using a smartcard and PIN to gain access is not only secure, but the process is easily manageable.
However, this is not the case in a tactical or combat situation.
For those chaotic situations, NextFlex partnered with the United States Army Combat Capability Development Command to make a flexible wireless FHE device that can be worn in the cuff of a shirt. The technology is in pre-production, pilot.
“Instead of having a hard card or disk that you normally have, you can imagine that the end goal of this project would be to create a device embedded in a cufflink or the user’s tissues, something you don’t notice,” he said. Sean Nachnani, a hardware systems engineer who led the project for NextFlex. “It’s just part of your outfit or uniform and doesn’t have that weight constraint. This is the beauty of FHE: it is so subtle, it conforms, it folds with you. You don’t notice it. “
Part of FHE’s manufacturing process is to cut the silicon chips to a thickness of a few tens of microns.
“That’s what’s exciting about the technology we’re doing, because by that point the silicon is foldable,” Veres said. “So, we’re making the overall circuit together with the silicon potentially flexible.”
The DoD safety device’s power and communications are wireless, so there are no ports for moisture and dust to enter.
The entire device is encased in a soft silicone resin obtained through an overmoulding process, which also offers protection against moisture, humidity and mechanical impact.
NextFlex did not complete the ingress protection tests. But other easily shielded devices are similarly rated to IP68, said Rob McManus, technical manager for software and testing.
The use of a similar wearable device could be applied to access safe places in industrial environments, hospitals and even homes.
While FHEs are critical to building better safety devices for the DoD, Lockheed Martin is using them to build small unmanned aerial systems (SUAS) like its Condor eXtended Endurance & Payload (XEP) they see around the corners.
Lockheed developed the Condor XEP in collaboration with the AFRL for intelligence, surveillance, reconnaissance / search and rescue operations.
It has a 143-inch wingspan and 68-inch fuselage and a communication range of approximately 9.3 miles. The Condor XEP is designed to mimic a larger vehicle at a significantly lower cost, be portable and hand-throwable.
The SUAS is equipped with a camera and a night vision device, but Steve Gonya, a researcher in Lockheed’s advanced manufacturing technology group, is leading efforts to add solar power and real-time high-definition video streaming. The team is also improving the Condor XEP’s satellite communication (SATCOM) capability.
In general, all these features have been included using conventional printed circuit boards, but “what it is doing is eliminating the rigid components and putting more and more circuit function only on the cables of the flexible circuits, eliminating the bulkier and heavier structures”, he said Gonya co-worker Mark Poliks, professor of engineering and director of the Center for Advanced Microelectronics Manufacturing at Binghamton University.
Gonya said he has already replaced a “big mouse nest” harness with FHE and added new circuit boards for power management.
To capture energy from the sun, it is using flexible, highly efficient, triple-junction gallium arsenide solar panels on the wings of the SUAS. The team is doing flight tests now.
“It doesn’t appear to affect the aerodynamic characteristics of the aircraft, but we are measuring how much power it generates,” said Gonya. “On a beautiful sunny day, a full array of solar cells on one wing should generate over 100 watts of power.”
One hundred watts is enough or close to the power needed for sustained flight, he said. By comparison, the lithium-ion batteries currently used to power the Condor XEP support approximately four hours of flight time.
A dual-band MIMO-COMM (Minimal Input-Minimal Output Communication) data link for real-time high-definition video streaming from the SUAS camera is also being tested.
The flexible and compliant antenna was designed by a team from the University of Massachusetts, Lowell. It looks like a patch attached to the underside of the SUAS wing. The MIMO-COMM replaces a blade antenna fixed perpendicular to the wings.
“It can practically bounce around corners,” Gonya said. “Normally that’s a bad thing, but for MIMO they can handle those multiple inputs. So, you can get a little better than the line of sight.
“Also, we wanted a nice spherical antenna model with no null points,” he said, contrasting the radiation pattern of the MIMO antenna with the donut-shaped model of an omnidirectional antenna. The radiation pattern of Omni antennas has middle-upper and mid-low signal loss.
Still to be added to the aircraft for testing are FHE for SATCOM capability for video uplinks beyond line of sight.
Most SATCOM communication openings are large and bulky, about the size of a breadbox. None of the commercially available openings will fit a Condor-sized SUAS.
“That was the most ambitious goal, satellite communication,” Gonya said.
Although a partnership with the Georgia Institute of Technology, Lockheed has developed a flexible aperture with electronics, circuitry, antenna elements and phase shifters all integrated to create a true beam steered phased array.
“The electronics are integrated with the antenna to control the range as the plane flies around and tries to follow the satellite,” Gonya said. “This is cutting edge stuff here. We have developed a sufficiently small and flexible aperture with enough gain that we can now integrate it with this Group 1 aircraft. “
The team is still testing the communication range.
While Lockheed Martin’s technology is state of the art, today’s cutting edge in flexible and compliant hybrid electronics could lead to tomorrow’s innovation that incorporates sensing and works even more closely with devices.
“I think it’s really the opportunity waiting for the future,” Poliks said. “We’ll see electronic item skins.”