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Closed-Loop Control of a Wing in an Unsteady Flow

Williams, David and Kerstens, Wesley and Buntain, Seth and Quach, Vien and Pfeiffer, Jens and King, Rudibert and Tadmor, Gilead and Colonius, Tim (2010) Closed-Loop Control of a Wing in an Unsteady Flow. In: 48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 4-7 January 2010, Orlando, FL.

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The lift response of the separated flow over a wing to different actuator input disturbances is used to obtain linear models useful for closed-loop control design. The wing has a small aspect ratio, a semi-circular planform, and is fully stalled at a 20° angle of attack. Individual pulse-like disturbances and step-input disturbances with randomized frequency were inputs to the actuator, and the lift coefficient increments were output signals. The "prediction error method" system identification technique was used to obtain two linear models of the separated flow. A 4th order model reproduced the non-minimum phase behavior of the pulse input, but did not work well for control purposes. The second model identified was limited to first order. The first order model proved to be useful for designing a proportional-integral feedback controller capable of suppressing lift oscillations in unsteady flows. Good suppression of lift oscillations was observed in the experiment after a step change in wind tunnel flow speed occurred. When the control system was tested with a randomized freestream velocity, it reduced the root-mean-square lift oscillation by 50 percent relative to the uncontrolled case.

Item Type:Conference or Workshop Item (Paper)
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URLURL TypeDescription Paper Paper
Colonius, Tim0000-0003-0326-3909
Additional Information:© 2010 by David R. Williams. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Published Online: 25 Jun 2012. The support for this work by the U.S. Air Force Office of Scientific Research MURI (FA9550-05-0369) with program manager Dr. Fariba Fahroo and contract FA9550-09-1-0189 with program manager Dr. Doug Smith is gratefully appreciated. David Williams gratefully acknowledges the partial support of the Alexander von Humboldt foundation. We also acknowledge the support from the Illinois NASA Space Grant Consortium for Wesley Kerstens and Seth Buntain.
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-05-0369
Air Force Office of Scientific Research (AFOSR)FA9550-09-1-0189
Alexander von Humboldt FoundationUNSPECIFIED
Subject Keywords:Aerospace Systems, Operations and Life Cycle
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AIAA Paper2010-358
Record Number:CaltechAUTHORS:20190717-102319753
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97208
Deposited By: Melissa Ray
Deposited On:18 Jul 2019 16:32
Last Modified:16 Nov 2021 17:29

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