Active flutter suppression - A flight test demonstration

Roger, Kenneth L.; Hodges, G.; Felt, Larry

doi:10.2514/6.1974-402

Cited by 7 publications

(2 citation statements)

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“…In the MP approximation method (Roger et al, 1975), each term of the aerodynamic matrix may be approximated by a polynomial ratio in s. Other modifications of the MP method are suggested by Karpel (1982). In this method, the number of augmented states is equal to the number of the denominator roots.…”

Section: Introductionmentioning

confidence: 99%

Aeroservoelasticity Analysis Method Based on an Error Analytical Form Applied on a Business Aircraft

Biskri

Botez

Σταθόπουλος

et al. 2008

Journal of Vibration and Control

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Aeroservoelasticity is a multidisciplinary study that combines the following disciplines: aerodynamics, aeroelasticity and servo-controls. For aeroelasticity studies, the Doublet Lattice Method (DLM) is used to calculate the aerodynamic unsteady forces for a set of reduced frequencies k and Mach numbers M on a business aircraft in the subsonic flight regime. There are three classical methods in the aeroservoelasticity used to approximate these forces Q1k2 M3 by rational functions in the Laplace domain Q11 s3: Least Square (LS), Matrix Padé (MP) and Minimum State (MS). A new method called Corrected Least Square (CLS) is presented. This new method uses an analytical form of the error as a function of Laplace variable similar to the analytical form of the aerodynamic forces calculated by use of the LS method. The new CLS method does not take additional time to the computation of the unsteady aerodynamic forces when compared to the LS method, and the aerodynamic forces calculated with the CLS method are closer to the aerodynamic forces data in the frequency domain than the aerodynamic forces calculated by the standard LS method. The new CLS method applied on a business aircraft gives better results (flutter speeds and frequencies) and faster (as it uses smaller number of lag terms) than the LS method.

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Section: Introductionmentioning

confidence: 99%

Aeroservoelasticity Analysis Method Based on an Error Analytical Form Applied on a Business Aircraft

Biskri

Botez

Σταθόπουλος

et al. 2008

Journal of Vibration and Control

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“…Most of these designs are supported by a few point sensors for feedback. Control designs 31,32,33,34 for AFS and GLA have traditionally relied on discrete arrays of single-point sensors, such as accelerometers, placed at selected locations on the aircraft wing or body. To our knowledge, there is currently no ongoing flutter research that utilizes a modal filter in the controller.…”

Section: Introductionmentioning

confidence: 99%

Modal Filtering for Control of Flexible Aircraft

Suh

Mavris

2013

54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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Modal regulators and deformation trackers are designed for an open-loop fluttering wing model. The regulators are designed with modal coordinate and accelerometer inputs respectively. The modal coordinates are estimated with simulated fiber optics. The robust stability of the closed-loop systems is compared in a structured singular-value vector analysis. Performance is evaluated and compared in a gust alleviation and flutter suppression simulation. For the same wing and flight condition two wing-shape-tracking control architectures are presented, which achieve deformation control at any point on the wing. Nomenclature= state matrix Accel = accelerometer AFS = active flutter suppression = balanced and reduced-order plant state matrix = number of accelerometers = control input matrix BWB = blended wing body = balanced and reduced-order input matrix = disturbance input weighting matrix for balanced and reduced-order plant = control input matrix for balanced and reduced-order plant = balanced = state space output matrix = balanced and reduced-order plant output matrix = output matrix transformation for accelerometers = state-regulated goal matrix for balanced and reduced-order plant = output matrix for balanced and reduced-order plant = number of control surfaces ̅ = mean aerodynamic chord = direct feedthrough matrix DFRC = Dryden Flight Research Center = control-regulated goal matrix for balanced and reduced-order plant = output noise weighting matrix for balanced and reduced-order plant = vector of deformations at fiber optic measurement stations = vector of virtual measurement deformations = vector of reference deformations at virtual measurement locations 2 ( ) = vector of deflections and rotations defined over at time ̈( ) = vector of accelerations and angular accelerations defined over at time EI = Effective Independence EOM = equations of motion = number of goal-regulated states and control surface movements = lower linear fractional transformation = plant GLA = gust load alleviation ( ) = class of all generalized plants with multiplicative input uncertainty ( ) = class of all generalized plants with multiplicative output uncertainty = gust model ( ) = matrix transfer function from disturbance to regulated output over all controllers ( ) = matrix transfer function from disturbance to regulated output = structural damping coefficient = sensor projection matrix (also referred to as hat matrix) = h infinity control type = scalar elements of the column and row of = identity matrix ( ) = imaginary part ̂ = imaginary number = matrix defined as = controller = control gain matrix = filter gain matrix = reduced frequency or non-dimensional frequency = system stability margin = global stiffness matrix ̃ = modal stiffness matrix = elemental stiffness matrix = leading edge = reference leading edge deflection at wing tip LFT = linear fractional transformation LQG = linear quadratic Gaussian LSE = least-squares estimation LTI = linear time-invariant = row vector index = row vector index for virtual deformation references = ...

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Aeroelasticity Research at Wright-Patterson Air Force Base (Wright Field) from 1953-1993

Harris

Huttsell

2003

Journal of Aircraft

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Active flutter suppression - A flight test demonstration

Cited by 7 publications

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Aeroservoelasticity Analysis Method Based on an Error Analytical Form Applied on a Business Aircraft

Aeroservoelasticity Analysis Method Based on an Error Analytical Form Applied on a Business Aircraft

Modal Filtering for Control of Flexible Aircraft

Aeroelasticity Research at Wright-Patterson Air Force Base (Wright Field) from 1953-1993

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