2/21/2013 April Dahlquist, CSL Communications
Written by April Dahlquist, CSL Communications
CSL researcher Naira Hovakimyan has received the American Institute of Aeronautics and Astronautics (AIAA) Mechanics and Control of Flight Award for 2011. The award is presented for an outstanding recent technical or scientific contribution by an individual in the mechanics, guidance, or control of flight in space or the atmosphere.
The award recognized Hovakimyan’s seven years of groundbreaking research on L1 robust adaptive control of nonlinear uncertain systems, vision-based guidance, navigation and control and cooperative path planning of UAVs. In particular, L1 adaptive control theory has enabled major flight tests on a subscale commercial jet at NASA (AirSTAR).
Her team's novel approach solved a problem that had prevented the computation of stability margins and performance bounds in adaptive control systems for more than 50 years.
"With this new formulation, all the results were developed smoothly and quickly," said Hovakimyan, an Illinois professor of mechanical science and engineering. "Moreover, we were able to address every challenge in every application that came our way in satisfactory manner."
Various applications, including flight tests of a subscale commercial jet (Generic Transport Model (GTM) of Airborne Subscale Transport Aircraft Research (AirSTAR) of NASA), cooperative control of UAVs, vision-based guidance of unmanned systems, have sucessfully employed L1 adaptive control theory. L1 adaptive control architecture helped to expand the post-stall flight envelope of the GTM aircraft up to 28 degrees in angle of attack and facilitated operation near stall and departure for longer periods of time. This allows for the collection of dynamic data for a wide range of flight conditions, including low angle of attack, moderate angle of attack, stall, departure and recovery, with a single maneuver. In recent flight tests of NASA, L1 adaptive flight control law supported modeling of unsteady aerodynamics at stall.
Hovakimyan describes the control system as a "better autopilot" in that it prevents the human pilot from over-correcting the plane in the presence of uncertainties.
Consider the same principle applied to a car driving on an icy road. If the car slips, the driver breaks, but the car may not necessarily slide in the desired direction. To compensate, the driver may break harder, possibly making the situation worse by trying to “over-control” the car. With Hovakimyan’s control system, a plot would be prevented from overcompensating in the event of strong wind or ice.
The theory could be applied to many types of networked systems. Hovakimyan’s work has already attracted the attention of companies such as Seagate, a manufacturer of hard drives and storage solutions; StatOil, an energy company; and Schlumberger, an information technology firm that specializes in the oil and gas industry.
Also part of Hovakimyan’s team are PhD student Enric Xargay (aerospace engineering) and Hovakimyan’s former postdoctoral student, Chengyu Cao, who is now a faculty member at the University of Connecticut.
“Their support in the past seven years’ research has been incredible,” Hovakimyan said.