Active Vibration Isolation System for Helicopter Interior Noise Reduction

Maier, Rudolf; Hoffmann, Falk; Tewes, Stefan; Bebesel, M.

doi:10.2514/6.2002-2495

Cited by 13 publications

(4 citation statements)

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“…Actuation system. As shown in Figure 15, similar to the concept in Sutton et al, 9 Gembler et al, 10 and Maier et al, 11 on each strut three piezoelectric actuators are evenly arranged in circumferential direction, which allows the control of both longitudinal and lateral vibrations of the strut. Three steal struts are used to support the gearbox.…”

Section: Methodsmentioning

confidence: 90%

Experimental investigations on active control of multifrequency helicopter vibrations using discrete model predictive sliding mode control

Yang

Wang

2017

Proceedings of the Institution of Mechanical Engineers, Part G:

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The presented experimental results illustrate the recent advances in the reduction of multifrequency vibrations of helicopter fuselage using an active control of structural response system. Recently, to cancel the multifrequency helicopter vibrations, a hybrid control approach has been proposed combining the filtered-x least mean square algorithm with a discrete model predictive sliding mode controller. To verify its effectiveness and self-adaptability, a set of active control experiments of structural response are conducted on a free-free elastic beam, which simulates a helicopter in flight. Considering that the helicopter vibrations in practical applications are much more complex, the further experiments of real-time active control are performed using a model helicopter test system. Higher discrete frequency components, which are actually of concern, are selected as the control objectives during the tests. The algorithm's control effects are sufficiently checked by single-input single-output and multiple-input multiple-output tests under different excitation conditions. For many cases the attenuation of measured response exceed level of 20 dB, with maximum reduction reaching 34.1 dB. These two sets of tests confirm that the active control system is practical for canceling the multifrequency helicopter vibrations.

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Section: Methodsmentioning

confidence: 90%

Experimental investigations on active control of multifrequency helicopter vibrations using discrete model predictive sliding mode control

Yang

Wang

2017

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…Three magnetostrictive actuators were clamped to the strut to introduce secondary forces that finally realized attenuation in the range of 30-40 dB in the kinetic energy of vibration over the frequency range of 250-1250 Hz. In addition, Eurocopter Deutschland and the EADS Corporate Research Center introduced smart struts to control the structure-borne sound transmitted via the struts to the fuselage [7,8]. The smart strut consists of piezoelectric actuators that are directly bonded to the BK117 support struts and provides good effectiveness at controlling the noise of multiple gear mesh frequencies in a flight test.…”

Section: Introductionmentioning

confidence: 99%

Research on the Vibration Characteristics of a Compounded Periodic Strut Used for Helicopter Cabin Noise Reduction

Yang

Wang

2017

Shock and Vibration

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A special periodic strut is developed to reduce the helicopter cabin noise in this paper. The strut exhibits unique dynamic characteristics which can isolate the gearbox vibrations from transferring to the fuselage and radiating noise. Modeling, simulation, and experimental research are carried out to explore its characteristics and performance. A theoretical model of the strut is firstly established, with particular emphasis on correlating the passband and stop band behaviors with the damping and a series of boundary conditions. Then, through simulations, it is shown that both the damping and boundary conditions have significant influences on the stop band, including the beginning and end frequencies and attenuation effects. Based on these analytical simulations, experimental analyses are conducted with the newly developed strut. Inspiring performances are validated under different conditions. Considering that the helicopter vibration in practical applications is much more complex, further experimental investigations are carried out on a helicopter model, which generates prominent gear mesh tones similar to a real helicopter. The experimental results show that the compounded periodic strut can significantly attenuate the vibrations transmitted to the fuselage. Compared with the plain strut, attenuations in excess of 40 dB are measured in the frequency range from 300 to 2000 Hz.

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“…Baz, and Asiri [5][6][7] investigated periodic structures and their use in active controls. Gembler, Maier, and Hoffmann [8][9][10] established an active vibration isolation technique by using active gearbox struts with multilayer piezoelectric stacks and applied filtered-x LMS algorithm to achieve reduction at the primary gear mesh frequency. However, while one principal gear-meshing frequency can be considerably mitigated, it is difficult to manage broadband frequencies.…”

Section: Introductionmentioning

confidence: 99%

Active Vibration Attenuation of Smart Material Systems With Model-Based and Nonlinear Multispectral Controllers

Kim

Washington

Singh

2009

Volume 1: Active Materials, Mechanics and Behavior; Modeling, Simulation and Control

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Many efforts have been concentrated on the active noise and vibration control with smart material systems. However, previous studies are limited to the reduction of a single frequency. Thus, more investigations are needed on multispectral control, which deals with multiple frequency components simultaneously. The main objective of this research is to establish a model-based and nonlinear multispectral controller by integrating the least mean squares (LMS) algorithm with model-based controllers. It is expected that multispectral signals are managed appropriately by model-based controls and nonlinear control covers the nonlinearity, model uncertainty, and other unexpected conditions. Performances of the proposed algorithms are validated with simulations and experiments in various cases. Novel methodologies developed in this research are expected to be employed for numerous applications in active vibration and noise control studies such as structural vibration attenuation, vehicle vibration and noise reduction, and active struts for aircrafts, helicopters, and other vibrating platforms.

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Active Vibration Isolation System for Helicopter Interior Noise Reduction

Cited by 13 publications

References 0 publications

Experimental investigations on active control of multifrequency helicopter vibrations using discrete model predictive sliding mode control

Experimental investigations on active control of multifrequency helicopter vibrations using discrete model predictive sliding mode control

Research on the Vibration Characteristics of a Compounded Periodic Strut Used for Helicopter Cabin Noise Reduction

Active Vibration Attenuation of Smart Material Systems With Model-Based and Nonlinear Multispectral Controllers

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