Efficiency of an ANC system in the tractor cabin under controlled engine workload

2020 ◽  
Vol 68 (5) ◽  
pp. 339-357
Author(s):  
Roberto Fanigliulo ◽  
Lindoro Del Duca ◽  
Laura Fornaciari ◽  
Renato Grilli ◽  
Roberto Tomasome ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Engine Performance ◽  
Noise Spectrum ◽  
Broadband Noise ◽  
Frequency Noise ◽  
Residual Noise ◽  
Agricultural Tractor

The noise at the driver seat of an agricultural tractor is produced mostly by the engine. Its characteristic broadband noise spectrum varies considerably with engine workload. The passive noise control techniques adopted in tractor cabins, based on the application of sound-absorbing and sound-proofing materials, are effective against medium-high frequencies noise components. The residual noise in sound-proof cabins is characterized by tonal emissions with low frequency components (< 500 Hz) but regarded as responsible for various disorders and diseases following long-term exposure. In addition to the "A" weighting filter adopted to evaluate occupational exposure to noise, other approaches are reported in the scientific literature considered more appropriate to evaluate low frequency noise (LFN), as well as studies testifying the effectiveness of active noise control (ANC) technologies in the low frequency range. In this article, the performance of an ANC system is evaluated in its ability to reduce noise levels inside the soundproof cabin of an agricultural tractor. To test this system, spectro-phonometric measurements of the equivalent linear sound pressure level were conducted under controlled and repeatable engine workloads, obtained by connecting the tractor to a dynamometric brake, while simultaneously acquiring the related engine performance curves. Altogether, three different couples of loudspeakers were tested. Frequency analysis in one-third octave band showed that the ANC system was mainly effective against LFN components (below 120 Hz) with peaks of reduction up to 20 dB. Then, on the basis of indications from previous studies, the data of linear sound pressure levels were processed applying the "A", "B", and "C" weighting filters, to show the different emphasis given to the effects of the system. Eventually, a point-by-point composition of the equivalent levels of sound pressure was drawn over the whole range of the engine, to highlight the conditions in which the ANC system was more effective.

scholarly journals Acoustic notch filtering earmuff utilizing Helmholtz resonator arrays

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258842
Author(s):  
Fumiya Mizukoshi ◽  
Hidetoshi Takahashi
Keyword(s):  
Resonant Frequency ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Helmholtz Resonator ◽  
Honeycomb Structure ◽  
Sound Insulation ◽  
Frequency Noise ◽  
Target Frequency ◽  
Notch Filtering

In recent years, noisy bustling environments have created situations in which earmuffs must soundproof only specific noise while transmitting significant sounds, such as voices, for work safety and efficiency. Two sound insulation technologies have been utilized: passive noise control (PNC) and active noise control (ANC). However, PNC is incapable of insulating selective frequencies of noise, and ANC is limited to low-frequency sounds. Thus, it has been difficult for traditional earmuffs to cancel out only high-frequency noise that people feel uncomfortable hearing. Here, we propose an acoustic notch filtering earmuff utilizing Helmholtz resonator (HR) arrays that provides a sound attenuation effect around the tuneable resonant frequency. A sheet-like sound insulating plate comprising HR arrays is realized in a honeycomb structure. Since the resonant frequency is determined by the geometry of the HR arrays, a highly audible sound region can be designed as the target frequency. In this research, the acoustic notch filtering performance of the proposed HR array plate is investigated in both simulations and experiments. Furthermore, the fabricated earmuffs using the novel HR array plates achieve a sound insulation performance exceeding 40 dB at the target frequency, which is sufficiently high compared to that of conventional earmuffs. The experimental results confirm that the proposed device is a useful approach for insulating frequency-selective sound.

scholarly journals Study of a Nonlinear Membrane Absorber Applied to 3D Acoustic Cavity for Low Frequency Broadband Noise Control

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1138 ◽  
Author(s):  
Jianwang Shao ◽  
Tao Zeng ◽  
Xian Wu
Keyword(s):  
Degrees Of Freedom ◽  
Noise Control ◽  
Normal Modes ◽  
Low Frequency ◽  
Harmonic Balance Method ◽  
Nonlinear Normal Modes ◽  
Broadband Noise ◽  
Frequency Noise ◽  
Acoustic Cavity ◽  
Nonlinear Membrane

As a new approach to passive noise control in low frequency domain, the targeted energy transfer (TET) technique has been applied to the 3D fields of acoustics. The nonlinear membrane absorber based on the TET can reduce the low frequency noise inside the 3D acoustic cavity. The TET phenomenon inside the 3D acoustic cavity has firstly investigated by a two degrees-of-freedom (DOF) system, which is comprised by an acoustic mode and a nonlinear membrane without the pre-stress. In order to control the low frequency broadband noise inside 3D acoustic cavity and consider the influence of the pre-stress for the TET, a general model of the system with several acoustic modes of 3D acoustic cavity and one nonlinear membrane is built and studied in this paper. By using the harmonic balance method and the numerical method, the nonlinear normal modes and the forced responses are analyzed. Meanwhile, the influence of the pre-stress of the nonlinear membrane for the TET is investigated. The desired working zones of the nonlinear membrane absorber for the broadband noise are investigated. It can be helpful to design the nonlinear membrane according the dimension of 3D acoustic cavity to control the low frequency broadband noise.

Experimental Study on an Active Noise Control System for Turboprop Driven Aircraft

2013 ◽  
Vol 333-335 ◽  
pp. 2142-2145
Author(s):  
Qing Fu Kong ◽  
Yu Liang Dai ◽  
Shi Jian Zhu ◽  
Jia Ming Wu
Keyword(s):  
Experimental Study ◽  
Control System ◽  
Sound Source ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Experimental Platform ◽  
Active Noise

In order to find a solution to the control of low frequency noise in the cabin of turboprop driven aircraft, an experimental active noise control (ANC) system is introduced in the paper, which consists of vibroacoustic field analogue subsystem, acoustic field measurement subsystem and acoustic barrier exciter subsystem. Effects of both different spaces between the primary sound source and secondary sound source of the ANC system and different frequency noises on noise-reduction result are investigated based on the experimental platform. Results of the experiment show a significant potential of the ANC method for the control of low frequency noise in the cabin of turboprop driven aircraft.

scholarly journals Portable Low-Frequency Noise Reduction Device for Both Small Open and Closed Spaces

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Chao Wang ◽  
Haiyang Gao ◽  
Liyao Yu ◽  
Tiantian Yu ◽  
Wenhui Yan ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Open Space ◽  
Active Noise Control ◽  
Low Frequency ◽  
Noise Pollution ◽  
Noise Spectrum ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Pollution Problem ◽  
Negative Impacts

Noise pollution has been given more attention due to its negative impacts on human health and disease. The portable low-frequency noise reduction device we developed in this research can provide an effective way for solving low-frequency noise pollution problem in the small space. This work describes the design principle and the prototype structures for two versions of V1.5 and V2.0 and builds the noise test systems for small spaces, respectively. These devices, installed on the outer surface of the small spaces, can automatically identify the noise spectrum and implement noise reduction by means of the active noise control (ANC) technology. The testing results indicate that the noise can be reduced 12 dB in the range of 250 Hz~400 Hz for the small closed space while, for the small open space, the best effect of 5.88 dB occurs in the optimal frequency of 450 Hz. These effects will be weakened with the increasing distance away from the source and show the obvious axisymmetric distribution in the inverted cone space.

Optimal parametric design of delayless subband active noise control system based on genetic algorithm optimization

2021 ◽  
pp. 107754632110016
Author(s):  
Guo Long ◽  
Yawen Wang ◽  
Teik C Lim
Keyword(s):  
Genetic Algorithm ◽  
Control System ◽  
Noise Control ◽  
Parametric Design ◽  
Active Noise Control ◽  
Low Frequency ◽  
Broadband Noise ◽  
Algorithm Optimization ◽  
Genetic Algorithm Optimization ◽  
Active Noise

Active noise control systems are generally application-specific, and an appropriate algorithm with an optimal configuration is desirable in the first stage of active noise control system design and deployment. This study presents a design of the subband active noise control system with optimal parameters for a practical broadband active noise control. Although the delayless subband active noise control has gained wide attention for broadband noise cancellation, an optimal design remains a challenge because of the complex interplay between multiple factors such as spectral leakage, delay and weight stacking distortion subject to a number of configurable parameters, and weight stacking method. The configurable parameters can hardly be optimized independently because the active noise control performance depends on the combined configuration. A simple near black box active noise control algorithm optimization model is thus established by incorporating the genetic algorithm optimization into the parametric design of the delayless subband algorithm. The automated process does not require an understanding of the performance characteristics for different parameters. The significance of applying the automated genetic algorithm optimization to the complex multiparameter nonlinear active noise control design is revealed by numerical simulations, particularly for the multichannel low-frequency broadband active noise control system configured with the delayless subband algorithms. This provides a way for the optimal parametric design of subband active noise control before being used in a practical complex scenario.

Simulation of Active Noise Control System on the Truck Interior Cab

2013 ◽  
Vol 798-799 ◽  
pp. 443-447
Author(s):  
Qi Chen LU ◽  
Hui Bin LI ◽  
Hua Huang
Keyword(s):  
Control System ◽  
Control Systems ◽  
Active Control ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Frequency Noise ◽  
Simulink Model ◽  
Active Noise ◽  
Active Control System

Studying on adaptive active noise control (AANC) system of the truck interior cab to reduce the low-frequency noise,a normalization FLMS algorithm simulink model is established in Matlab/Simulink.Then taking it as the core,a feedforward adaptive active control system and a feedback adaptive active control system of the tuck interior cab are established in Matlab/Simulink .Considerating the actual error channels effects on systems ,the noise reduction effects of two adaptive active control systems are verified from the simulintion results.Through comparing the two wo adaptive active control systems,we found that the feedforward adaptive active control system is more stable.

scholarly journals Application Study of Adaptive Tracking Algorithm in Active Noise Control System of Transformer

2019 ◽  
Vol 9 (13) ◽  
pp. 2693 ◽  
Author(s):  
Liming Ying ◽  
Jinwei Wang ◽  
Qin Liu ◽  
Donghui Wang
Keyword(s):  
Noise Reduction ◽  
Noise Control ◽  
Spectral Characteristics ◽  
Active Noise Control ◽  
Low Frequency ◽  
Cost Effective ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Active Noise ◽  
Reduction Methods

Active noise control (ANC) technology can be able to reduce the low frequency noise effectively, and has been widely applied in limited enclosed equipment, such as cars, aircraft cockpits, and headphones, etc. Compared with the traditional noise reduction methods, ANC technology is a cost-effective method in handling the low-frequency noise of transformers. An experimental ANC system in a virtual substation is designed and constructed. An adaptive signal tracking ANC algorithm is proposed, and a set of ANC experimental prototypes applied to a virtual substation is designed. Based on the proposed algorithm, the distributions of the acoustics and spectral characteristics of transformer noise in substations are analyzed. Experimental results show that the effective noise reduction can be achieved an average of 5 dB(A) in a given region with respect to the absence of the ANC system.

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