Feed Forward Multiple-Input Active Noise Control Systems

2003 ◽  
Author(s):  
A. R. Ohadi ◽  
H. Mehdigholi ◽  
E. Esmailzadeh
Keyword(s):  
Control Systems ◽  
Noise Source ◽  
Reference Signal ◽  
Active Noise Control ◽  
Open Loop ◽  
Noise Sources ◽  
Active Noise ◽  
Multiple Input ◽  
Feedforward Controller ◽  
Adaptive Feedforward

The use of adaptive feedforward controllers has proven to be a very successful strategy for controlling noise and vibration in a variety of applications. One reason is that the feedforward controller is an open loop controller, which can be designed to cancel the undesired noise in one position with any accuracy. However, the feedforward controller requires an input signal, called a reference signal, correlated to the noise source. As a consequence, a single reference controller can only reduce noise radiated from a single noise source. In many applications, there is a need to attenuate noise produced by several noise sources. In this paper, three different structures, single, modulating and individual controllers, for multiple input feedforward controllers have been studied and some design aspects are investigated.

Implementation of coherence-based-selection multi-channel wireless Active Noise Control in headphone

2021 ◽  
Vol 263 (4) ◽  
pp. 1945-1953
Author(s):  
Xiaoyi Shen ◽  
Dongyuan Shi ◽  
Woon-Seng Gan ◽  
Santi Peksi
Keyword(s):  
Numerical Simulations ◽  
Noise Reduction ◽  
Noise Control ◽  
Noise Source ◽  
Reference Signal ◽  
Active Noise Control ◽  
Selection Algorithm ◽  
Noise Sources ◽  
Active Noise ◽  
Reference Signals

Active noise control (ANC) headphone is widely used to attenuate the noise around human' s ear. The microphone mounted on the conventional ANC headphones collected the mixed reference signals when more than one noise sources are often present in the surrounding. In this case, the uncorrelated noise sources involved in the mixed reference usually deteriorate the noise reduction performance of the ANC headphones. To solve this problem, wireless microphones are proposed to install close to each potential noise source in the environment. The microphones pick up the clean reference signals and transmit them to the ANC controller embedded in the headphones with time-advance wirelessly. Every reference signal selected by a coherence-based-selection algorithm is provided individual control filter in each ear. Each control filter updated by using a single clean reference offers better noise reduction performance for ANC headphones. Furthermore, numerical simulations and real-time experiment results in this paper demonstrate the improvement of the proposed method compared with conventional ANC headphones.

Numerical Evaluation of the Performance of Active Noise Control Systems

1990 ◽  
Vol 112 (2) ◽  
pp. 230-236 ◽  
Author(s):  
C. G. Mollo ◽  
R. J. Bernhard
Keyword(s):  
Boundary Element ◽  
Control Systems ◽  
Noise Control ◽  
Noise Source ◽  
Numerical Technique ◽  
Active Noise Control ◽  
Boundary Element Methods ◽  
Single Input Single Output ◽  
Active Noise ◽  
Analytical Approaches

Most of the approaches to the prediction of the effectiveness of active noise control systems are analytical in nature. Analytical approaches are limited to active noise control systems where a solution to the governing acoustic wave equation is available. The objective of the investigation presented in this paper was to develop a generalized numerical technique for evaluating the optimal performance of active noise controllers. The numerical technique used as the basis of the numerical analysis is the indirect boundary element method (IBEM). Boundary element methods have been shown to be straightforward and accurate numerical methods for the prediction of the acoustic response of a system. The IBEM numerical procedures are used here to derive the active noise controllers for optimal control of enclosed harmonic sound fields where the noise source strengths or the enclosure boundary description may not be known. Detectors are introduced into the system to deduce the unknown noise source strengths. The performance prediction for a single input, single output system is presented. Analysis of the stability and observability of the active noise control system employing detectors is also presented.

Implementation of a single-channel active noise control system with multiple reference sensors

2020 ◽  
Vol 68 (5) ◽  
pp. 358-366
Author(s):  
H.E. Oh ◽  
W.B. Jeong ◽  
C. Hong
Keyword(s):  
Single Channel ◽  
Control Method ◽  
Reference Signal ◽  
Active Noise Control ◽  
Multiple Source ◽  
Weighted Sum ◽  
Reference Signals ◽  
Feedforward Controller ◽  
Channel Control ◽  
Source Signals

When multiple sources contribute competitively to the noise level, multi-channel control architecture is needed, leading to more cost and time for control computation. We, hence, are concerned with a single-channel control method with a single-reference signal obtained from a linear combination of the multiple source signals. First, we selected 3 source signal sensors for the reference signals and the error sensor, selected a proper actuator and designed the controllers: 3 cases of single-channel feedforward controllers with a single-reference signal respectively from the source signals, a multi-channel feedforward controller with the reference signals from the source signals, and the proposed controller with the reference signal from weighted sum of the source signals. The weighting factors and the filter coefficients of the controller were determined by the FxLMS algorithm. An experiment was then performed to confirm the effectiveness of the proposed method comparing the control performance with other methods for a tower air conditioner. The overall sound pressure level (SPL) detected by the error sensor is compared to evaluate their performance. The reduction in the overall SPL was obtained by 4.74 dB, 1.96 dB and 6.62 dB, respectively, when using each of the 3 reference signals. Also, the overall SPL was reduced by 7.12 dB when using the multi-reference controller and by 7.66 dB when using the proposed controller. Conclusively, under the multiple source contribution, a single-channel feed forward controller with the reference signal from a weighted sum of the source signals works well with lower cost than multi-channel feedforward controller.

Sign in / Sign up

Export Citation Format

Share Document