Adaptive feedforward multiple-input, multiple-output active noise control

An enhanced multiple-input multiple-output (MIMO) filtered-x least mean square (FXLMS) algorithm using improved virtual secondary path is proposed as the basis for an active noise control (ANC) system for treating vehicle powertrain noise. This new algorithm is developed to overcome the limitation caused by the frequency-dependent property of the standard FXLMS algorithm and to reduce the variation of convergence speed inherent in multiple-channel cases, in order to improve the overall performance of the control system. In this study, the convergence property of the proposed algorithm is analyzed in the frequency domain in order to yield a better understanding of the physical meaning of the virtual secondary path. In practice, because of the arrangement and sensitivities of the actuators (speakers), transducers (microphones), and physical environment, the magnitude response of the main secondary paths can be very different from each other. This difference will cause difficulty in the overall convergence of the algorithm, which will result in minimal attenuation at some of the channels. The proposed channel equalized (CE) virtual secondary path algorithm is designed to tackle this difficulty by equalizing the mean magnitude level of the main secondary paths and by adjusting other secondary paths correspondingly to keep the coupling effects among the control channels unchanged. The performance of the proposed algorithm is validated by analyzing a two-input two-output active powertrain noise control system.

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Adaptive Feedforward Active Noise Control in an Acoustic Duct

Volume 6B: 18th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc2001/vib-21482 ◽

2001 ◽

Author(s):

A. R. Ohadi ◽

E. Esmailzadeh ◽

A. Alasty

Keyword(s):

Noise Control ◽

Active Noise Control ◽

Superior Performance ◽

Single Input Single Output ◽

Single Output ◽

Active Noise ◽

Input Signals ◽

Single Input ◽

Simulation Results ◽

Adaptive Feedforward

Abstract The single-reference/multi-output active noise control (ANC) of an accurate physical model of an acoustic duct system has been investigated. Computer model of a multi-channel ANC system with tonal and sweep sine input signals, and an adaptive feedforward algorithm that minimizes the generic cost function are developed. Results obtained for various single-input/single-output (SISO) configurations of ANC systems were compared. The dynamic response of a single-reference/multi-output ANC system, using Minimax and MEFXLMS algorithms, is studied and the effect of acoustical feedback neutralization in a multichannel ANC system is studied. Simulation results demonstrate that the multi-channel adaptive feedforward ANC system, using the Minimax algorithm, has a superior performance in comparison to the same system with MEFXLMS.

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Feed Forward Multiple-Input Active Noise Control Systems

Dynamic Systems and Control, Volumes 1 and 2 ◽

10.1115/imece2003-43000 ◽

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.

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Feedforward and Feedback Control Strategy for Active Noise Cancellation in Ducts

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2802332 ◽

1996 ◽

Vol 118 (2) ◽

pp. 372-378 ◽

Cited By ~ 4

Author(s):

Jwu-Sheng Hu

Keyword(s):

Multiple Input Multiple Output ◽

Sound Field ◽

Theoretical Work ◽

Noise Cancellation ◽

Active Noise Cancellation ◽

Active Noise ◽

Multiple Input ◽

Input Multiple Output ◽

Output System ◽

Feedback Control Strategy

This paper presents the theoretical work about active noise cancellation in ducts. The proposed control system is designed based on the assumption of a one-dimensional sound field. The controller consists of a feedforward block which serves as a noise observer. The feedback portion of the control algorithm is to minimize residual disturbances. Closed-loop stability of the MIMO (multiple-input-multiple-output) system is analyzed and the result shows that the dynamic influenced by the space-feedforward and feedback controllers can be decoupled. Both semi-infinite and finite-length ducts are considered in this study and simulation examples are given to illustrate the effectiveness of the proposed controllers.

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