- TITLE: A "New" Approach to Active
Noise Control in Ducts
- AUTHORS: Mehta, P., Zheng, Y., Chait, Y., and Hollot, C.V.
- ABSTRACT: In this paper we consider the fixed-filter design
approach for active noise control (ANC) in ducts. Based on a large body
of literature during the past decade that deals strictly with adaptive
filter solutions (see \cite{fuller} and references contained therein)
the fixed-filter approach appears to be all but discarded for this application.
The ANC system under consideration has a similar configuration to those
used in most adaptive implementations; i.e., a duct equipped with both
feedforward and feedback sensors and a control speaker. Our design of
a linear, time-invariant controller involves three steps: (1) system
identification from the experimental duct frequency response, (2) $H_{\infty}$
synthesis using the identified plant and model errors, and (3) use of
Quantitative Feedback Theory (QFT) to further improve performance by
sequential tuning of the feedback and feedforward filters using the
experimental data. Preliminary experiments indicate that attenuation
levels of $10$--$30$ dB are achievable over a $400$ Hz band without
amplification in the immediate range. An important consequence of LTI
designs is that performance is guaranteed for wide-band noise as well
as pure tone disturbances -- in adaptive schemes stability and performance
may be very difficult (if impossible) to guarantee beforehand. This
paper focuses on the third step of our three-step approach -- the QFT
design aspect -- (the other two steps are described in \cite{ifac}).
- STATUS: in Active Control of Vibration and Noise, ASME Vol. DE, pp.
25-36 (presented at the Active Control of Vibration and Noise Symposium,
ASME ICE, Nov. 17-22, 1996).
- DATE OF ENTRY: November 07, 1996
- full paper (postscript, 98KB)
accompanying figures (postscript file,
1,097KB)
Zip file (147KB)
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