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Design, test, and evaluation of three active flutter suppression controllersThree control law design techniques for flutter suppression are presented. Each technique uses multiple control surfaces and/or sensors. The first method uses traditional tools (such as pole/zero loci and Nyquist diagrams) for producing a controller that has minimal complexity and which is sufficiently robust to handle plant uncertainty. The second procedure uses linear combinations of several accelerometer signals and dynamic compensation to synthesize the model rate of the critical mode for feedback to the distributed control surfaces. The third technique starts with a minimum-energy linear quadratic Gaussian controller, iteratively modifies intensity matrices corresponding to input and output noise, and applies controller order reduction to achieve a low-order, robust controller. The resulting designs were implemented digitally and tested subsonically on the active flexible wing wind-tunnel model in the Langley Transonic Dynamics Tunnel. Only the traditional pole/zero loci design was sufficiently robust to errors in the nominal plant to successfully suppress flutter during the test. The traditional pole/zero loci design provided simultaneous suppression of symmetric and antisymmetric flutter with a 24-percent increase in attainable dynamic pressure. Posttest analyses are shown which illustrate the problems encountered with the other laws.
Document ID
19930000882
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Adams, William M., Jr. (NASA Langley Research Center Hampton, VA, United States)
Christhilf, David M. (Lockheed Engineering and Sciences Co. Hampton, VA., United States)
Waszak, Martin R. (NASA Langley Research Center Hampton, VA, United States)
Mukhopadhyay, Vivek (NASA Langley Research Center Hampton, VA, United States)
Srinathkumar, S. (National Aeronautical Lab. Bangalore, India)
Date Acquired
September 6, 2013
Publication Date
October 1, 1992
Subject Category
Aircraft Stability And Control
Report/Patent Number
NASA-TM-4338
NAS 1.15:4338
L-17041
Accession Number
93N10070
Funding Number(s)
PROJECT: RTOP 505-64-20-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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