Dissertation > Industrial Technology > General industrial technology > Acoustic engineering > Vibration, noise and its control > Vibration and noise control and its use

Research on the System of Noise Isolation Based on Active Noise Control

Author XieLuJi
Tutor SongLeiMing
School Beijing Jiaotong University
Course Vehicle Engineering
Keywords Sound insulation structure Active Noise Control LMS algorithm Filtered-XLMS algorithm Single-frequency signal
Type Master's thesis
Year 2012
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With the rapid development of the Chinese railway, our lives become more and more convenient. From the initial speed of200km/h EMU to the new speed of380km/h EMU, the Chinese railway career has been developed rapidly. In the12th five years plan, we will make the speed of500km/h EMU. These are our achievements or will be our achievements. However, after the improving the speed of EMU, a noise problem begins to be serious. Around the railway the noise need to be controlled, and the acoustic environment in the train also need to be improved. Traditional noise control technology is for the noise in the high-frequency, but it is less effective to control the noise in the low-frequency. Now, there is an active noise control technology, which is concerned by many experts. And it is effective to control the noise in the low-frequency.Active Noise Control (ANC) technology in the sound insulation structure is studied in the paper. First of all, the theory and algorithm of the ANC is analyzed and derived, and then by the LabVIEW software the control system is simulated and analyzed. The LMS algorithm and the filtering-XLMS algorithm are analyzed on the noise reduction effect of the single-frequency signal. For example of the filtering-XLMS algorithm, the effect of the control system is analyzed on the different controller order, the different convergence step, and the different controller initialization conditions. At last, an ANC System is built in a double plane sound insulation structure, and the control effect of the entire system is studied in an anechoic and reverberation chamber. Inside and outside the double plane sound insulation structure sound pressure is monitored. At the location of the error sensor the noise reduction effect is obvious and the noise reduction effect of the double plane sound insulation structure is also improved. So, controlling the sound. pressure inside the double plane sound insulation structure by ANC method can improve the sound insulation in the low frequency, and improve the entire sound insulation of the double plane sound insulation structure.

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