FlexFlight Project

 

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Nonlinear Flexibility Effects on Flight Dynamics and Control of Next-Generation Aircraft

 

Da Ronch, A., Tantaroudas, N.D., and Badcock, K.J. (University of Liverpool, Liverpool, U.K.)

 

Simpson, R., Wang, T., Wynn, A., Hesse, H., and Palacios, R.N. (Imperial College, London, U.K.)

 

Goulart, P. (Swiss Federal Institute of Technology, Zurich, Switzerland)

 

Airbus UK, BAE Systems, DSTL, QinetiQ

 

UK Engineering and Physical Sciences Research Council (EPSRC)

 

Nonlinear Model Reduction

A nonlinear reduced order model is used to reduce the computational cost and dimension of the large-order nonlinear system for a practical control law design. The approach uses information on the eigenspectrum of the coupled system Jacobian matrix and projects the system through a series expansion onto a small basis of eigenvectors representative of the full-order dynamics.

2 DoFs Pitch Plunge Aerofoil

An aerofoil free to move in pitch and plunge is the test case. The aerodynamic model contains the contributions from deflections of the trailing-edge flap and for the interaction with gusts, both discrete and continuous in the time domain. More details on the model setup, description and results can be found in Ref. [1].

Pitch Plunge Aerofoil - Linear Structural Model

 

Pitch-plunge aerofoil - dynamic aeroelastic response to a sinusoidal gust with a linear structural model; the terms FOM and ROM indicate, respectively, the full-order and reduced-order models.

Pitch Plunge Aerofoil - Linear/Nonlinear Structural Model

 

Pitch-plunge aerofoil - dynamic aeroelastic response to a sinusoidal gust; the terms FOM and NFOM indicate, respectively, the full-order model with linear and nonlinear structural parameters.

Pitch Plunge Aerofoil - Nonlinear Structural Model

 

Pitch-plunge aerofoil - dynamic aeroelastic response to a sinusoidal gust with a nonlinear structural model; the terms NFOM and NROM indicate, respectively, the nonlinear full-order and nonlinear reduced-order models.

Pitch Plunge Aerofoil - Damped natural frequency

 

Damped natural frequency of pitch and plunge eigenvalues for varying freestream speed (λ = -ζωn ± jωd). Results from simulation are compared to experimental data from the wind tunnel of the University of Liverpool.

Pitch Plunge Aerofoil - Damping ratio

 

Damping ratio of pitch and plunge eigenvalues for varying freestream speed (λ = -ζωn ± jωd). Results from simulation are compared to experimental data from the wind tunnel of the University of Liverpool.

3 DoFs Pitch Plunge Aerofoil

ADD DESCRIPTION/RESULTS

2 DoFs Pitch Plunge Aerofoil with Rigid Body Translation

ADD DESCRIPTION/RESULTS

References

[1] Da Ronch, A., Badcock, K.J., Wang, Y., Wynn, A., and Palacios, R.N., "Nonlinear Model Reduction for Flexible Aircraft Control Design," AIAA Atmospheric Flight Mechanics Conference, Minneapolis, Minnesota, 13-16 Aug. 2012.
AIAA Paper 2012-4404