WRIGHT-PATTERSON AIR FORCE BASE, Ohio — The tropical fish tank sitting in the center of the lab would not be so unusual if this were a biology classroom. But encountering one inside a facility housing the Air Force Research Laboratory’s materials and manufacturing directorate is an unexpected sight.
Lab researchers here increasingly are studying and mimicking Mother Nature’s products. The hope is that the research will one day lead to advances including tiny aircraft that fly and act like birds and insects and bio-inspired sensors that can out-snuff Fido’s nose.
“The lab is making some concerted efforts in a number of areas to understand how nature does what it does and to see how we can apply them,” said Maj. Gen. Ellen Pawlikowski, commander of the Air Force Research Laboratory. Biological sciences research is a new and “very important” area for the future of the Air Force, she added.
In the lab with the fish tank, Richard Vaia, the acting chief of the nanostructured and biological sciences branch, picked up a Petri dish containing a sliver of clear film. It was dotted with small squares that glinted like holographic stickers in the light. Rotating the dish vertically, he said researchers have figured out how to turn silk nano-fibers into tiny optical devices. He shined a green laser light through one of the squares. On the wall, an image of an eye appeared.
Scientists are combining that breakthrough in nanomaterials with structures inspired by nature, Vaia said. Butterfly wings, for example, produce color not through chromophores, or parts of molecules that absorb light, but through the structures of the wings themselves.
“If you change what’s on the surface of the butterfly wing, it changes colors,” Vaia said as he sprayed an iridescent violet and black specimen with alcohol. The wing glittered momentarily in reds and oranges before turning back to its original colors. “You can take silk, a much more stable material, and the type of hierarchical structures of butterfly wings, and combine them to make robust sensors,” he said.
The Defense Advanced Research Projects Agency recently funded AFRL, in collaboration with GE and other partners, $6.3 million to create bio-inspired nanostructured sensors capable of quickly detecting chemical warfare agents and explosives. The researchers aim to build a prototype that can indicate the presence of toxic substances by detecting as few as only 100 molecules in a test volume of several milliliters.
“This is still lab-scale stuff, so we’re not there yet,” said Vaia. But the hope is one day to put military bomb-sniffing dogs out of business.
AFRL also is funding efforts at the Air Force Institute of Technology’s advanced navigation technology center, which is looking to biology for inspiration to solve the challenge of flying when the Global Positioning System is not available.
Lt. Col. Mike Veth, deputy director of the center, is leading work in vision-based navigation for the indoor environment.
“We look at examples in nature. How do animals navigate? They don’t use GPS and they can do a great job,” he said. Robins and pigeons can see the magnetic field of the Earth with their eyes and they use it to help them fly long distances. Humans rely on all their senses, including vision, hearing and tiny inertial sensors embedded within the vestibular system, to get around.
Researchers also are examining how animals process sensory information to navigate. They tend to use non-linear processing and parallel computation techniques, which scientists are beginning to understand and exploit using advanced computer technologies.
One of the school’s navigation projects is developing algorithms for cooperative sensing and mapping, said John Raquet, director of AFIT’s advanced navigation technology center. Teams of students have built prototype vehicles with suites of cameras, LIDAR and other sensors that allow robots to communicate amongst themselves and collaboratively solve tasks. “It’s a very powerful tool because you can add something new to the mix or take something away, and they’ll just figure out how to do it,” he said.
The vehicles can autonomously enter a building, locate a target, such as a possible explosive inside a red tube, and designate a fellow robot with a gripping arm to investigate the suspected bomb.
Another group of students is applying the same technology and concept to flying robots. The autonomous collaboration will allow groups of unmanned aircraft to execute missions with little to no monitoring by an operator.
Until those technologies mature, the Air Force will continue to pilot aircraft remotely from ground control stations. To help operators perform hours-long missions, scientists at the 711th Human Performance Wing are investigating ways to detect operator fatigue and alleviate the stress of flying multiple vehicles at one time. They have experimented with subjects who voluntarily wore oximeters on their fingers and electroencephalography electrodes on their heads to advance the understanding of the human body’s signals under duress.
The challenge is finding a way to detect those signals without forcing airmen to wear devices or distracting them from their tasks, said James Christensen, a neuroscientist in the human effectiveness directorate.
Several commercial companies have produced technologies that rely on off-board sensors to track a person’s fatigue level while sitting at a computer workstation. The systems employ infrared cameras and illuminators to detect head and eye positions. They are tied into computers that measure blink rates and track where a person is looking.
“That’s the direction we’d like to be going,” said Christensen. “The more we can do in that vein, the better, from my point of view.” Eventually, scientists want to connect those fatigue and stress detectors into automated systems that can help compensate for operators’ declining performance by alleviating them of certain tasks.
“We’re not trying to build a Terminator. What I’m trying to do is allow him to be relieved from as much as possible,” said Pawlikowski. “We are flying lots of Predators, taking lots of full motion video, collecting different pieces of information. The human mind can’t digest all that, but computers can.”