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Out of Cold War's end, Hovakimyan has emerged as a leading voice in flight control safety

Naira Hovakimyan has a background as a mathematician, which dates back to humble beginnings in Armenia. Over the last 17 years, however, researchers in the United States have tapped Hovakimyan’s calculations to help advance work in the stability of flight control systems. In March, her research group’s L1 control method was successfully tested in a Learjet plane at Edwards Air Force Base in California.

Naira Hovakimyan
Naira Hovakimyan
Hovakimyan, now a professor of mechanical science and engineering and Schaller Faculty Scholar at the University of Illinois, was a college student during the end of the Cold War. She completed a master of science degree in theoretical mechanics and applied mathematics in 1988 from Yerevan State University in Armenia, one  of 15 republics of the former Soviet Union. Armenia seceded from the USSR in 1991 and while the move brought freedom for Armenia as an independent state, not having an established financial freedom and an air and rail blockade from neighboring countries crippled the economy and put most of its people out of work.

“It was not clear how to live,” Hovakimyan said. “We went five years without electricity or energy, living with oil lamps and candles. In those conditions, you don’t wake up and think about going to work. People were exchanging real estates for a one-way ticket out of the country to go to a place where life was normal.”

The country’s instability prompted Hovakimyan to further her education in Moscow, completing a PhD in physics and mathematics from the Institute of Applied Mathematics of Russian Academy of Sciences in 1992. The Russian culture of mathematics was very much theory based for its own beauty.

“In Russian culture, as long as you impress another mathematician who may be more famous than you, then, 'wow,' and that’s more or less the end of the story,” Hovakimyan said. “In the western world, people are looking for how it can be applied. In academia, if you want to get your students excited, you bring these applications into your group.”

She was looking for any opportunity to be able to stay in science, and with conditions in Armenia in disarray, she was prepared for that opportunity to come in a different country.

From 1994-98, she traveled the world taking advantage of offers to study and teach. Because Germany was one of the first countries to establish an embassy in the newly formed Republic of Armenia, Hovakimyan applied for, and was granted, a scholarship as a German Academic Exchange Service scholar at Stuttgart University. She had similar opportunities in subsequent years in France and Israel, while also earning a Young Investigator Best Paper Award in Japan.

Her career path was set in motion in 1998 when she received an invitation from Georgia Tech, looking for a mathematician of her skill set to join the team there in studying the stability of flight control.

“It wasn’t my original dream or plan, as I had no prior training in flight dynamics or flight control,” Hovakimyan recalled. “However, a flight control system involves questions related to stability and robustness of performance and this problem is very mathematical in nature. Stability is something I had good training on back in Russia, so I took the challenge.”

Hovakimyan spent the next five years with consecutive six-month appointments, not knowing when the appointment might end. However, she slowly became absorbed in the research and churned out impressive papers on the subject, catching the eye of several sponsors of basic research.

Meanwhile, sponsored by both the Air Force and NASA, Hovakimyan found a position as an associate professor at Virginia Tech in 2003. It was there that Hovakimyan, jointly with postdoctoral fellow Chengyu Cao (now on faculty at University of Connecticut), developed the L1 adaptive control theory, that can aid a pilot to regain control of an airplane in sudden and drastic circumstances. She and Chengyu Cao wrote a book on their L1 adaptive control theory.

“Once we developed it, NASA came along with opportunities of how to apply it,” Hovakimyan said. “NASA was working on their own aviation safety program. They wanted to have an aircraft in a facility that could model flying in the wind tunnel.”

NASA tested a 5.5 percent subscale general transport model aircraft for a variety of challenging conditions and testing it for aggressive maneuvers.

“From the nine controllers that were tried in flight, L1 adaptive controller was the only one surviving the stall and post-stall conditions, giving the pilot a fully controllable aircraft. L1 controller was eventually used for modeling unsteady aerodynamics in stall and post-stall conditions, including the departure edges of the flight envelope,” Hovakimyan said.

Once the group had applications up and running, she accepted an invitation to join the faculty at the University of Illinois in 2008.

The goal of the L1 adaptive control is for an aircraft to maintain nominal handling qualities and prevent unfavorable aircraft-pilot interactions in the presence of aircraft failures (changes in aerodynamics, loss of control, coupling between control channels, shifts in center of gravity, etc.).  For instance, if the airplane hits a wind gust and goes into stall (instability), losing lift, L1 adaptive control maintains the roll stability so the pilot could put the nose down and recover.

Over the past 12 years, the system has been tested in a series of advanced conditions to prove that it works.

Hovakimyan’s Advanced Controls Research Lab at Illinois has maintained close ties to NASA. From 2009-11, NASA Langley tested the system on the AirSTAR dynamically scaled Generic Transport Model research aircraft. TuDelft conducted piloted simulation evaluations on the SIMONA motion-based research simulator in 2011.

Following the successful NASA Langley flight tests, her research garnered international recognition. Hovakimyan received the AIAA Mechanics and Control of Flight Award (2011) and the prestigious Alexander von Humboldt Research Award (2014).

From left to right: Enric Xargay, Irene Gregory, Naira Hovakimyan and Chengyu Cao ready for a test at the NASA Langley AirSTAR Sim Development Facility in 2011.
From left to right: Enric Xargay, Irene Gregory, Naira Hovakimyan and Chengyu Cao ready for a test at the NASA Langley AirSTAR Sim Development Facility in 2011.
While these tests were performed on unmanned aircraft, that all changed in March when the L1 robust adaptive control was successfully used aboard a manned Learjet at Edwards Air Force Base.  

Over the course of three weeks, two B-52 pilots, an F-16 pilot, two flight test engineers, and two safety pilots performed rigorous evaluations in varying flight conditions. The team tested for seven failure configurations and in each case the system allowed the aircraft to recover uniformly, consistently, and predictably.

“The Learjet test was successful in a sense that it helped us verify the theory on a manned aircraft with seven different failure configurations,” Hovakimyan said.

NASA is planning to fly a hybrid airplane, combining the benefits of multi-roters. Hybrid platforms will give a confidence in vertical takeoff and landing capabilities to allow for transition to longer flights.

Ultimately, Hovakimyan would like for the L1 flight control to have an impact on commercial aircraft.

“Boeing has flight control systems that they have invested billions, which doesn’t make sense to replace, but they could have ours as a back-up,” Hovakimyan said.

In addition to commercial aviation, Hovakimyan’s team has had several inquires in the drone market. The University of Illinois and NASA have patented the L1 adaptive controller with certain government rights. The patent has been licensed to IntelinAir, a company which is building drones for precision farming, surveying and infrastructure inspection.

Hovakimyan has also received inquiries from the Illinois Emergency Management Agency (IEMA) about integrating the system into drones for public safety applications, like fires and tornados. The IEMA will present the work at a conference in September. Students at Illinois will work on the project in summer.

In addition she is consulting Statoil in Norway on how to use the method in drilling applications. Raymarine has commercialized an autopilot for high-speed boats.

Life in Armenia has stabilized over the last two decades, but it was those tumultuous years that ultimately propelled Hovakimyan to her role as a leading voice in flight control systems. Her family is still in Armenia, and, while she admits that she never saw her stay in America lasting this long, she is proud of the fact that her hard work in the USA is making a difference in air safety.

“Illinois has given me a lot of opportunities and resources that have resulted in some great accomplishments,” Hovakimyan said. “I am excited to see what we can continue to do in the future.”