Feedforward active noise controller design in ducts without independent noise source measurements

Abstract The purpose of this paper is to propose an experimental design methodology for global active noise control in an enclosed space. We aim to control the noise caused by an internal noise source. Since each enclosed space has different acoustic characteristics, it is difficult to design different controllers suitable for each enclosed space. So, we decided to design a controller that could be used universally. The basic concept is the collocation of noise source and control speakers to generate a sound field opposite in phase to the noise source in a free field. For implementation of the proposed method, we propose a configuration method of control speakers and error microphones, and an active noise control algorithm. Also, to confirm the applicability of the proposed method, we design a controller in an anechoic chamber, which represents a free field condition, and perform active noise control in other enclosed spaces with the controller designed for the anechoic chamber. The experimental results show that the solution calculated in the free field condition can be used in other enclosed spaces without any modifications.

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Experimental investigation on the potential of the Feedback Fx-LMS Active Noise Control technology for use in industrial generator sets

E3S Web of Conferences ◽

10.1051/e3sconf/202131208007 ◽

2021 ◽

Vol 312 ◽

pp. 08007

Author(s):

Marco Ciampolini ◽

Lorenzo Bosi ◽

Luca Romani ◽

Andrea Toniutti ◽

Matteo Giglioli ◽

...

Keyword(s):

Acoustic Waves ◽

Noise Control ◽

Noise Source ◽

Acoustic Noise ◽

Active Noise Control ◽

Lms Algorithm ◽

Destructive Interference ◽

Exhaust Pipe ◽

Least Mean Square ◽

Active Noise

Active Noise Control (ANC) has been considered a promising technology for the abatement of acoustic noise from the mid-20th century. Feedback and Feedforward ANC algorithms, based on the destructive interference principle applied to acoustic waves, have been developed for different applications, depending on the spectrum of the noise source. Feedback ANC algorithms make use of a single control microphone to measure an error signal which is then employed by an adaptive filter to estimate the noise source and generate an opposite-phase control signal. The Fx-LMS (Filtered-X Least Mean Square) algorithm is mostly adopted to update the filter. Feedback ANC systems have proven to be effective for the abatement of low-frequency quasi-steady noises; however, different challenges must be overcome to realize an effective and durable system for high-temperature application. This paper aims at experimentally assessing the feasibility of a Feedback Fx-LMS ANC system with off-line Secondary Path estimation to be used in mid-size diesel gensets for the reduction of the exhaust noise. Several solutions are proposed, including the mechanical design, the development of the Fx-LMS algorithm in the LabVIEW FPGA programming language, and the key features required to prevent parts from thermal damage and fouling. The developed prototype was implemented on a 50-kW diesel genset and tested in a semi-anechoic chamber. The noise abatement inside the exhaust pipe and at different measurement points around the machine was evaluated and discussed, showing good potential for improving the acoustic comfort of genset users.

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Controller design for active noise control of compressor by using the time window POCS technique

Journal of Mechanical Science and Technology ◽

10.1007/s12206-020-0602-9 ◽

2020 ◽

Vol 34 (7) ◽

pp. 2693-2700

Author(s):

Jeong-Mo Ku ◽

Weui-Bong Jeong ◽

Chinsuk Hong

Keyword(s):

Noise Control ◽

Controller Design ◽

Time Window ◽

Active Noise Control ◽

Active Noise

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A Comparative Study Reducing Road Noise Using Active Noise Cancelation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.641-642.793 ◽

2014 ◽

Vol 641-642 ◽

pp. 793-798

Author(s):

Won Pyoung Kang ◽

Hak Ryong Moon ◽

You Jin Lim

Keyword(s):

Comparative Study ◽

Frequency Band ◽

Road Traffic ◽

Noise Source ◽

Traffic Noise ◽

Low Frequency ◽

Lms Algorithm ◽

Road Traffic Noise ◽

Active Noise ◽

Noise Cancelation

This research has developed the active noise cancelation (ANC) equipment for reducing road traffic noise. This ANC equipment is consisted of microphones, controllers and speakers. This research has conducted simulation by using the noise source that was recorded at the roads to confirm the ANC equipment. The simulation conducted in the field used 1 non-directional speaker and 2-directional speakers. Also, this simulation applied the Fx LMS algorithm. The result of this study showed that the non-directional speaker was shown to reduce the maximum of 5.5 dB (A) in low frequency band. And, the 2 directional speakers was shown to reduce the noise for 2.5 dB (A) and 3.8 dB (A), respectively. This equipment did not diffuse anyexternal influence and operated stably.

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