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Reduction of helicopter vibration through cyclic control of variable orifice dampers

Published online by Cambridge University Press:  04 July 2016

P. Anusonti-Inthra ,
F. Gandhi  and
L. Miller
P. Anusonti-Inthra
Affiliation:
Rotorcraft Center of Excellence, Department of Aerospace Engineering, The Pennsylvania State University, Pennsylvania, USA
F. Gandhi
Affiliation:
Rotorcraft Center of Excellence, Department of Aerospace Engineering, The Pennsylvania State University, Pennsylvania, USA
L. Miller
Affiliation:
Lord Corporation, Thomas Lord Research Center, Cary, USA
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Abstract

The present study demonstrates that cyclically varying the damping coefficient of controllable lag and flap dampers can reduce the 4/rev vibratory hub loads of a four-bladed hingeless rotor helicopter in high speed forward flight. Gradient-based optimization is used to determine the optimal multi-cyclic damping variation inputs that minimise a composite vibration index comprising of all six components of vibratory hub loads. Optimal 2/rev and 3/rev variations in the lag damping coefficient virtually eliminate the vibratory hub drag force and yawing moments, and produce small reductions in the vibratory hub side force. The optimal lag damping variations, interestingly, produce increases in the 3/rev and 5/rev components of the blade root drag shear, that cancel the contributions of the blade root radial shear to the vibratory in-plane hub forces. Despite some increases in higher harmonics of blade response, damper loads, and blade and flexbeam root loads, the lower harmonics and the peak-to-peak values show little change, implying that blade and damper fatigue life would not be adversely affected. When optimal 2/rev and 3/rev variations in flap damping coefficient are introduced in conjunction with the optimal lag damping variations, 30% reductions in the hub vertical vibrations are obtained, in addition to the previous reductions in the vibratory in-plane forces and yawing moment. The cyclic flap damping variations reduce the higher harmonics of the blade root vertical shear. Reductions in hub vibration levels are obtained over a range of forward flight speeds.

Type
Research Article
Information
The Aeronautical Journal , Volume 107 , Issue 1077 , November 2003 , pp. 657 - 672
Copyright
Copyright © Royal Aeronautical Society 2003 

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References

1. Reichert, G., Helicopter vibration control — survey, Vertica, 1981, 5, (1), pp 1–20.Google Scholar
2. Lowey, R.G., Helicopter vibrations: a technological perspective, J American Heli Soc, 1984, 29, (4), pp 4–30.Google Scholar
3. Nguyen, K. Higher Harmonic Control Analysis For Vibration Reduction of Helicopter Rotor Systems, 1989, PhD Thesis, University of Maryland.Google Scholar
4. Milgram, J.H. and Chopra, I., A parametric design study for actively controlled trailing edge flaps, J American Hel Soc, 1998, 43, (2), pp 110–119.Google Scholar
5. Welsh, W., Fredrickson, C., Rauch, C. and Lyndon, I., Flight test of an active vibration control system on the UH-60 Black Hawk helicopter, May 1995 Proceedings of the American Helicopter Society 51st Annual Forum, pp 393–402.Google Scholar
6. Staple, A.E., An evaluation of active control of structural response as a means of reducing helicopter vibration, 1989, Proceedings of the 15th European Rotorcraft Forum, Amsterdam, Netherlands, September 1989, pp 51.1–51.18. Google Scholar
7. Ganguli, R. and Chopra, I., Aeroelastic optimization of an advanced geometry helicopter rotor, J American Heli Soc, 1996, 41, (1), pp 18–28.Google Scholar
8. Chen, P. and Chopra, I., Induced strain actuation of composite beams and rotor blades with embedded piezoceramic elements, 1994, Proceedings of the SPIE on Smart Structures and Materials.Google Scholar
9. Jacklin, S.A., Blaas, A., Teves, D., and Kube, R., Reduction of helicopter BVI noise, vibration and power consumption through individual blade control, 1995, Proceedings of the American Helicopter Society 51st Annual Forum, May 1995, pp 662–680.Google Scholar
10. Shaw, J. et al Higher harmonic control: wind tunnel demonstration of fully effective vibratory hub force suppression, J American Heli Soc, 1989, 34, (1).Google Scholar
11. Nitzsche, F., Smart spring-type actuation for helicopter individual blade control, 1996, Sixth International Conference on Adaptive Structures, Technomic, Lancaster-Basel, 1996, pp. 230–240.Google Scholar
12. Nitzsche, F., Smart-spring actuation for helicopter individual blade control: A frequency domain analysis, 1997, Seventh International Conference on Adaptive Structures, Technomic, 1997, pp 331–341.Google Scholar
13. Anusonti-Inthra, P. and Gandhi, F., Helicopter vibration reduction through cyclic variations in blade root stiffness, J Intell Mater Sys and Struc, 2000, 11, (2), pp 153–166.Google Scholar
14. Anusonti-Inthra, P. and Gandhi, F., Optimal control of helicopter vibration through cyclic variations in blade root stiffness, Smart Mater and Struc, Special Issue on Rotorcraft Application, 2001, 10, (1), pp 86–95.Google Scholar
15. Gandhi, F. and Anusonti-Inthra, P., Helicopter vibration reduction using discrete controllable-stiffness devices at the rotor hub, J Aircr, 2002, 39, (4), pp 668–677.Google Scholar
16. Yang, J.N., Wu, J.C. and Li, Z., Control of seismic-excited buildings using active variable stiffness systems, Eng Struc, 1996, 19, (9), pp 589–596.Google Scholar
17. Patten, W.N., Mo, C., Kuehn, J. and Lee, J., A primer on design of semiactive vibration absorbers (SAVA), J Eng Mech, 1998, 124, (1), pp. 61–68.Google Scholar
18. Sadek, F. and Mohraz, B., Semiactive control algorithms for structures with variable dampers, J Eng Mech, 1998, 124, (9), pp 981–990.Google Scholar
19. Gavin, H.P. and Doke, N.S., Resonance suppression through variable stiffness and damping mechanisms, 1999, Proceedings of the SPIE Smart Structures Conference, SPIE 3671, March 1999, pp 43–53.Google Scholar
20. Krasnicki, E.J., Comparison of analytical and experimental results for a semi-active vibration isolator, The Shock and Vibration Bulletin, 1980, 50, (4), pp 69–76 The Shock and Vibration Information Center, Naval Research Laboratory.Google Scholar
21. Krasnicki, E.J., The experimental performance of an off-road vehicle utilizing a semi-active suspension, The Shock and Vibration Bulletin, 1984, 54, (3) pp 135–142. The Shock and Vibration Information Center, Naval Research Laboratory.Google Scholar
22. Hrovat, D., Margolis, D.L. and Hubbard, M., An approach toward the optimal semi-active suspension, J Dynamic Systems, 1988, Measurement and Control, 110, pp 288–296.Google Scholar
23. Karnopp, D., Design principles for vibration control using semi-active dampers, J Dynamic Systems, 1990, Measurement and Control, 112, pp 448–455.Google Scholar
24. Symans, M.D. and Constantinou, M.C., Semi-active control systems for seismic protection of structures: a state-of-the-art review, Engineering Structures, 1999, 21, pp 469–487.Google Scholar
25. Symans, M.D., Constantinou, M.C., Taylor, D.P. and Granjost, K.D., Semi-active fluid viscous dampers for seismic response control, 1994, Proceedings of First World Conference on Structural Control, Pasadena, California, FA4-3 FA4-12.Google Scholar
26. Marathe, S., Gandhi, F. and Wang, K.W., Helicopter blade response and aeromechanical stability with a magnetorheological fluid based lag damper, J Intell Mater Sys and Struct, 1998, 9, (4), pp 272–282.Google Scholar
27. Kamath, G.M., Wereley, N.M. and Jolly, M.R., Characterization of magnetorheological helicopter lag dampers, J American Heli Soc, 1999, 44, (3), pp 234–248.Google Scholar
28. Bir, G., Chopra, I. et al University of Maryland advanced rotorcraft code (UMARC) theory manual, UM-AERO Report 92-02, 1992.Google Scholar
29. Tauszig, L., Numerical Detection and Characterization of Blade-Vortex Interactions Using a Free Wake Analysis, 1998, MS Thesis, Department of Aerospace Engineering, the Pennsylvania State University.Google Scholar
30. Gandhi, F. and Tauszig, L., A critical evaluation of various approaches for the numerical detection of helicopter blade-vortex interactions, J American Heli Soc, 2000, 45, (3), pp 179–190.Google Scholar
31. Johnson, W., Self-tuning regulators for multicyclic control of helicopter vibration, March 1982, NASA Technical Paper 1996.Google Scholar