Analise teorica e experimental de estrategias de controle ativo de ruido

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

This work describes applications of the active noise control techniques using adaptive feed forward filtering theory, where the objective is to analyze energetic behavior of the controlled system. The active noise control methods employed are the normalized filtered-X LMS in the time and frequency domain and the Active Sound Intensity Controller (ASIC), which is developed and implemented in the frequency domain. This thesis is divided m two main parts. In the first part, the active noise control methods are applied in an one-dimensional waveguide constituted by a T-shaped duct with two acoustic sources. The one-dimensional waveguide was modeled by the Spectral Element Method (SEM). In this experiment, the measurements include the sound intensity, the radiated acoustic power, and the partic1e velocity. The theoretical and experimental results show that the spectral element method can be used successfully to predict the acoustic phenomena in one-dimensional waveguides. Besides, there is no significant difference when different active noise control strategies are implemented, even when the cost functions were changed (the change in the error sensor type means a change in the cost function). In the second part, the normalized filtered-X LMS in the time domain is applied to attenuate the interior noise m a cylindrical cavity. The adaptive control schemes implemented were the Active Control of Vibration (A VC) and the Active Structural Acoustic Control (ASAC). Result obtained when the primary noise is generated by mechanically exciting the cylindrical shell and by using an external acoustical source are compared. It is shown that if the interior noise is generated by shaking the cylindrical shell, it is better to apply the A VC scheme, while if the interior noise is generated by an external acoustical source it is better to apply the ASAC scheme

ASSUNTO(S)

controle de ruido guias de ondas som - intensidade vibração

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