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Analysis of helicopter vibratory hub loads alleviation by cyclic trailing-edge blade flap actuation

Published online by Cambridge University Press:  03 February 2016

M. Gennaretti
Affiliation:
[email protected], University Roma Tre, Department of Mechanical and Industrial Engineering, Rome, Italy
M. Molica Colella
Affiliation:
G. Bernardini
Affiliation:

Abstract

The aim of the present work is the investigation about the use of blade trailing-edge flaps for the reduction of vibratory loads arising at the hub of helicopter main rotors in forward flight. The alleviation of these loads is achieved through multicyclic higher harmonic actuation of the blade flaps, which is related to measured vibratory loads amplitude. The feedback control law is obtained by an optimal control process based on the minimisation of a cost function, under the constraint of compatibility with the nonlinear equations governing blade aeroelasticity. In the numerical investigation concerning a four-bladed rotor in level flight conditions, a computationally efficient local controller methodology is applied, with the attention focused on the effectiveness of the control algorithm, along with its robustness with respect to differences (existing in real applications) between the aeroelastic models used for control law synthesis and validation.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 2009 

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References

1. Patt, D., Liu, L. and Friedmann, P.P., Rotorcraft vibration reduction and noise predictions using a unified aeroelastic response simulation, J American Helicopter Society, 2005, 50, (1), pp 95106.Google Scholar
2. Zhang, J., Active-Passive Hybrid Optimization of Rotor Blades with Trailing Edge Flaps, PhD Thesis, Department of Aerospace Engineering, The Pennsylvania State University, 2001.Google Scholar
3. Viswamurthy, S.R. and Ganguli, R., Performance sensitivity of helicopter global and local optimal harmonic vibration controller, Computers and Mathematics with Applications, 2008, 56, pp 24682480.Google Scholar
4. Hodges, D.H. and Dowell, E.H., Nonlinear equation for the elastic bending and torsion of twisted nonuniform rotor blades, NASA TN D-7818, 1974.Google Scholar
5. Hodges, D.H. and Ormiston, R.A., Stability of elastic bending and torsion of uniform cantilever rotor blades in hover with variable structural coupling, NASA TN D-8192, 1976.Google Scholar
6. Theodorsen, T., General theory of aerodynamic instability and the mechanism of flutter, NACA Report 496, 1935.Google Scholar
7. Greenberg, J.M., Airfoil in sinusoidal motion in a pulsating stream, NACA TN-1326, 1947.Google Scholar
8. Drees, J.M., A Theory of airflow through rotors and its application to some helicopter problems, J Helicopter Association of Great Britain, 1949, 3, (2), pp 79104.Google Scholar
9. Gennaretti, M. and Bernardini, G., Novel boundary integral formulation for blade-vortex interaction aerodynamics of helicopter rotors, AIAA J, 2007, 45, (6), pp 11691176.Google Scholar
10. Gennaretti, M. and Bernardini, G., Aeroelastic response of helicopter rotors using a 3D unsteady aerodynamic solver, Aeronaut J, 2006, 110, (1114), pp 793801.Google Scholar
11. Johnson, W., Self-tuning regulators for multicyclic control of helicopter vibration, NASA TP-1996, 1982.Google Scholar
12. Gandhi, F. and Anusonti-Intra, P., Helicopter vibration reduction using discrete controllable-stiffness devices at the rotor hub, AIAA Paper 2001-1438, Proceedings of the 42nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Material Conference, Seattle, Washington, Seattle, 2001.Google Scholar
13. Nguyen, K., Betzina, M. and Kitaplioglu, C., Full-scale demonstration of higher harmonic control for noise and vibration reduction on the XV-15 Rotor, J American Helicopter Society, 2001, 46, (3), pp 182191.Google Scholar