scholarly journals Multi-Zone Active Noise Control Strategy for the Scattered Sound Control of an Infinite Rigid Cylinder

2021 ◽  
Vol 11 (21) ◽  
pp. 10011
Author(s):  
Yuwei Feng ◽  
Xiaolin Wang ◽  
Xiaoyan Cui ◽  
Ming Wu ◽  
Jun Yang
Keyword(s):  
Control Strategy ◽  
Acoustic Waves ◽  
Noise Control ◽  
Active Noise Control ◽  
Target Area ◽  
Rls Algorithm ◽  
Rigid Cylinder ◽  
Active Noise ◽  
Sound Control ◽  
Sound Amplification

Active noise control can be used to reduce the scattered sound of a reflecting object to make it invisible to incident acoustic waves. For the multi-zone active noise control of scattered sound from an infinite rigid cylinder, an active control strategy is proposed that combines the least absolute shrinkage and selection operator (LASSO) algorithm with constraint points and regularized least squares (RLS) algorithm. The proposed control strategy is used to promote control performance through optimizing the secondary loudspeaker placement of an active noise control system. Compared with the RLS algorithm employing the uniformly placed loudspeakers and the traditional LASSO algorithm, the proposed strategy has better reduction performance both in the forward-scattered and backward-scattered sound target areas, and there is less sound amplification in the far field. From 400 Hz–1100 Hz, the proposed strategy provides a 5 dB–16 dB reduction performance advantage in the target area compared to the RLS algorithm employing uniformly placed loudspeakers.

scholarly journals Noise analysis and active noise control strategy of transcranial magnetic stimulation device

AIP Advances ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 085010
Author(s):  
Chang Liu ◽  
Hongfa Ding ◽  
Xiao Fang ◽  
Zhou He ◽  
Zhixun Wang
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Control Strategy ◽  
Magnetic Stimulation ◽  
Noise Control ◽  
Noise Analysis ◽  
Active Noise Control ◽  
Active Noise

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

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.

Parallel Architecture of Reconfigurable Hardware for Massive Output Active Noise Control

2019 ◽  
Vol 29 (03) ◽  
pp. 1950014
Author(s):  
Diego Mendez ◽  
David Arevalo ◽  
Diego Patino ◽  
Eduardo Gerlein ◽  
Ricardo Quintana
Keyword(s):  
Acoustic Waves ◽  
Noise Control ◽  
Reference Signal ◽  
Active Noise Control ◽  
Computational Cost ◽  
Main Idea ◽  
Parallel Architecture ◽  
Acceptable Error ◽  
Active Noise ◽  
Fxlms Algorithm

Filtered-x Least Mean Squares (FxLMS) is an algorithm commonly used for Active Noise Control (ANC) systems in order to cancel undesired acoustic waves from a sound source. There is a small number of hardware designs reported in the literature, that in turn only use one reference signal, one error signal and one output control signal. In this paper, it is proposed a 3-dimensional hardware-based version of the widely used FxLMS algorithm, using one reference microphone, 18 error microphones, one output and a FIR filter of 400[Formula: see text] order. The FxLMS algorithm was implemented in a Xilinx Artix 7 FPGA running at 25 MHz, which allowed to update the filter coefficients in 32.44[Formula: see text] s. The main idea behind this work is to propose a pipelined parallelized architecture to achieve processing times faster than real time for the filter coefficients update. The main contribution of this work is not the ANC technique itself, but rather the proposed hardware implementation that utilizes integer arithmetic, which provided an acceptable error when benchmarked with a software implementation. This parallel system allows a scalable implementation as an advantage of using FPGA without compromising the computational cost and, consequently, the latency.

scholarly journals Suitability of Active Noise Barriers for Construction Sites

2020 ◽  
Vol 10 (18) ◽  
pp. 6160
Author(s):  
Shahin Sohrabi ◽  
Teresa Pàmies Gómez ◽  
Jordi Romeu Garbí
Keyword(s):  
Noise Control ◽  
Noise Source ◽  
Active Noise Control ◽  
Target Area ◽  
Construction Sites ◽  
Noise Barriers ◽  
Active Noise ◽  
Noise Barrier ◽  
Passive Noise ◽  
Suitable Location

Barriers are increasingly used to protect the pedestrian and neighboring buildings from construction noise activities. This study aims to investigate the suitability of applying active noise control on barriers in a construction site to protect the street area and neighboring buildings. Transducers that are simulated in this work are close to the barrier, and their optimal positions are defined in such a way that the control system has the maximum performance at the neighboring areas close to the construction sites. To begin with, the suitable location of the control sources is found when the total squared pressure is minimized at the positions of noise receivers. The suitable location of the error sensors is, then, found when the control sources are fixed at the position of the previous step and the total squared pressure is minimized at the error sensors. The best location for the error sensors is defined when the maximum reduction is achieved in the target area. It is observed that suitable positions for the transducers depend on the location of target areas for noise control, the position of the noise source, and its operating frequency. In this investigation, a unique configuration is proposed for the transducers that achieves a comparable reduction both at the street area and the neighboring buildings, simultaneously. The results show that the active noise barrier with a height of 2.5 m can achieve an extra insertion loss in the street zone, varies from 9.3 to 16.4 dB (in comparison with passive noise barrier) when the distance of the noise source from the barrier changes in the range of 7 to 1 m, respectively. Those values are of the same order for the passive noise attenuation. Furthermore, similar results are achieved when attempting to cancel the shadow zone of a façade 15 m away from the barrier.

Active Noise Control Algorithm with Saturated Actuator

2021 ◽  
Vol 263 (4) ◽  
pp. 2896-2904
Author(s):  
Hakjun Lee ◽  
Youngjin Park
Keyword(s):  
Control System ◽  
Control Algorithm ◽  
Noise Control ◽  
Motor Vehicle ◽  
Active Noise Control ◽  
Nonlinear Function ◽  
Target Area ◽  
Functional Link ◽  
Nonlinear Part ◽  
Active Noise

Active noise control system has received its attention in various technical field such as headphone, motor vehicle, etc. Meanwhile, filtered-x least mean square (FxLMS) algorithm is conventional linear algorithm used in active noise control system. It assumes that acoustic path from the noise source and control source to target area are linear. However, in actual system, the secondary path including a D/A converter, an amplifier, and an actuator may exhibits nonlinear distortion like saturation effects. To cope with this nonlinear effects, functional link artificial neural network (FLANN) has been proposed. FLANN uses nonlinear function expansion filter with FxLMS based control algorithm to control the nonlinear effect. In this paper, noise reduction performance and convergence speed are improved by modifying the conventional FLANN algorithm by decoupling the linear and nonlinear part of noise signal.

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