Journal ArticleDOI
Development of an acoustic actuator for launch vehicle noise reduction.
TLDR
This work presents a novel approach that uses a nonlinear buckling suspension system and partial evacuation of the air within the enclosure to yield a compact, sealed acoustic driver that exhibits a very low natural frequency.Abstract:
In many active noise control applications, it is necessary that acoustic actuators be mounted in small enclosures due to volume constraints and in order to remain unobtrusive. However, the air spring of the enclosure is detrimental to the low-frequency performance of the actuator. For launch vehicle noise control applications, mass and volume constraints are very limiting, but the low-frequency performance of the actuator is critical. This work presents a novel approach that uses a nonlinear buckling suspension system and partial evacuation of the air within the enclosure to yield a compact, sealed acoustic driver that exhibits a very low natural frequency. Linear models of the device are presented and numerical simulations are given to illustrate the advantages of this design concept. An experimental prototype was built and measurements indicate that this design can significantly improve the low-frequency response of compact acoustic actuators.read more
Citations
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Proceedings ArticleDOI
Survey of state-of-the-art vibration isolation research and technology for space applications
TL;DR: A broad survey of current literature detailing the current state-of-the-art and future research trends in vibration isolation for current and proposed space systems is presented in this article, where the vibration isolation problem is discussed taking into account nonlinearities of variable parameters.
Journal ArticleDOI
Active Structural-Acoustic Control of a Rocket Fairing Using Proof-Mass Actuators
TL;DR: In this article, the feasibility of using proof-mass actuators to control noise transmission actively into a small rocket fairing, given practical constraints on actuator power and mass, is explored.
Journal ArticleDOI
Adaptive positive position feedback for actively absorbing energy in acoustic cavities
TL;DR: In this paper, a self-tuning regulator is used in series with a high-and low-pass Butterworth filters for each controlled mode, and the inner control loop consists of an algorithm that locates the zero frequencies of the collocated signal and uses these values to update the resonance frequency of the positive position feedback filter.
Journal ArticleDOI
Active Acoustic Control of a Rocket Fairing Using Spatially Weighted Transducer Arrays
TL;DR: In this paper, the authors used spatially weighted transducer arrays with H2 feedback control laws to attenuate globally the targeted acoustic modes in a rocket fairing, and the results demonstrate that the controller was able to reduce the response of the low-frequency modes by 6 − 12 dB with very little spillover.
Dissertation
Control of sound transmission into payload fairings using distributed vibration absorbers and Helmholtz resonators
TL;DR: In this paper, a new passive treatment to reduce sound transmission into payload fairing at low frequency is investigated, which is composed of optimally damped vibration absorbers (DVA) and optimally Damped Helmholtz resonators (HR).
References
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Journal ArticleDOI
Active Structural-Acoustic Control of a Rocket Fairing Using Proof-Mass Actuators
TL;DR: In this article, the feasibility of using proof-mass actuators to control noise transmission actively into a small rocket fairing, given practical constraints on actuator power and mass, is explored.
Journal Article
Improving loudspeaker performance for active noise control applications
Steven A. Lane,Robert L. Clark +1 more
TL;DR: In this paper, a method to compensate a loudspeaker easily and reliably in order to approximate constant volume velocity behavior over the piston-mode frequency range is presented and demonstrated, which decouples the actuator from the system being controlled and reduces the impact of the loudspeaker dynamics over the control bandwidth.
Journal ArticleDOI
Active Acoustic Control of a Rocket Fairing Using Spatially Weighted Transducer Arrays
TL;DR: In this paper, the authors used spatially weighted transducer arrays with H2 feedback control laws to attenuate globally the targeted acoustic modes in a rocket fairing, and the results demonstrate that the controller was able to reduce the response of the low-frequency modes by 6 − 12 dB with very little spillover.