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Transonic Flutter Suppression Control Law Design Using Classical and Optimal Techniques with Wind-Tunnel ResultsThe benchmark active controls technology and wind tunnel test program at NASA Langley Research Center was started with the objective to investigate the nonlinear, unsteady aerodynamics and active flutter suppression of wings in transonic flow. The paper will present the flutter suppression control law design process, numerical nonlinear simulation and wind tunnel test results for the NACA 0012 benchmark active control wing model. The flutter suppression control law design processes using (1) classical, (2) linear quadratic Gaussian (LQG), and (3) minimax techniques are described. A unified general formulation and solution for the LQG and minimax approaches, based on the steady state differential game theory is presented. Design considerations for improving the control law robustness and digital implementation are outlined. It was shown that simple control laws when properly designed based on physical principles, can suppress flutter with limited control power even in the presence of transonic shocks and flow separation. In wind tunnel tests in air and heavy gas medium, the closed-loop flutter dynamic pressure was increased to the tunnel upper limit of 200 psf. The control law robustness and performance predictions were verified in highly nonlinear flow conditions, gain and phase perturbations, and spoiler deployment. A non-design plunge instability condition was also successfully suppressed.
Document ID
20040086829
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Mukhopadhyay, Vivek (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 1999
Subject Category
Aircraft Stability And Control
Report/Patent Number
AIAA Paper 99-1396
Meeting Information
Meeting: 40th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials (SDM) Conference
Location: Saint Louis, MO
Country: United States
Start Date: April 12, 1999
End Date: April 15, 1999
Sponsors: American Society of Civil Engineers, American Helicopter Society, Inc., American Inst. of Aeronautics and Astronautics, American Society for Composites, American Society of Mechanical Engineers
Distribution Limits
Public
Copyright
Public Use Permitted.

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