- TITLE: Active Noise Control in Ducts: Feedforward/Feedback
Design by Blending HINFINITY and QFT Methods
- AUTHORS: Mehta, P., Zheng, Y., Hollot, C.V., and Chait, Y.
- ABSTRACT: In this paper we take a closer look at the prevalent notion
that adaptive filters are preferred to fixed-filters in cancelling noise
in ducts. For this purpose, we consider an active noise control (ANC)
system with configuration similar to that 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 by using the experimental data. Preliminary
experiments indicate that attenuation levels of at least $10$--$20$
dB are achievable over a $400$ Hz band. An important consequence of
LTI designs is that the performance is guaranteed for wide-band noise
as well as pure tone disturbances and, unlike adaptive schemes, stability
and performance can be guaranteed beforehand.
- STATUS: Procs. 13th IFAC World Congress, Vol. H, pp. 191-197.
- DATE OF ENTRY: November 07, 1996
- full paper (postscript file, 141KB)
accompanying figures (postscript file, 79KB)
Zip File (52 KB)
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