Active Noise Cancellation for Ventilation Ducts Using a Pair of Loudspeakers by Sampled‐Data ℋ_∞ Optimization

Abstract

We deal with the design of active noise control systems for ventilation ducts with a pair of loud-speakers based on sampleddata H ∞ optimization, in order to improve our previous study with a single loudspeaker. The resultant controller requires lower computational complexity for the implementation, compared to the standard time-varying adaptive controllers, since it is time-invariant and the order is comparable. Moreover, the effect of Swinbanks' source is automatically recovered by the H ∞ optimization. The benefit of the proposed method is also confirmed from experimental results for a real house, where the achieved noise attenuation level is about twice as much as that of the single loudspeaker case.

A Control Source Structure of Single Loudspeaker and Rear Sound Interference for Inexpensive Active Noise Control

“…It is well known that the Swinbanks' (unidirectional) source [1] has advantages against a standard single loudspeaker (bidirectional source) in not only performances but also the implementation cost. Indeed, the performance improvement has been reported experimentally in both adaptive and robust control setups [2,3]. In addition, the possibility of inexpensive implementation has been pointed out by showing that the controller gain is lower and, as the result, lower amplitude of driving signal for loudspeakers are achieved by the Swinbanks' source [2,4], which enables us to use lower power loudspeakers.…”

“…Indeed, the performance improvement has been reported experimentally in both adaptive and robust control setups [2,3]. In addition, the possibility of inexpensive implementation has been pointed out by showing that the controller gain is lower and, as the result, lower amplitude of driving signal for loudspeakers are achieved by the Swinbanks' source [2,4], which enables us to use lower power loudspeakers. Furthermore, it has been shown that the advantages of Swinbanks' source are theoretically proved for a practical setting on the duct length and loudspeaker locations [5,6].…”

“…The validity of the proposed method will be shown by comparing to the existing two structures of control sources, namely, the standard single loudspeaker (bidirectional source) and the Swinbanks' (unidirectional) source, in terms of the open-loop characteristic and the closedloop performances based on both mathematical models and experimental results. Figure 1 and Table 1, respectively, show a block diagram and instruments of the experimental apparatus which are similar to that in [2] except that a real ventilation fan is replaced to a loudspeaker (SPK1) as a noise source, and the duct length is shortened to simplify mathematical models. Two loudspeakers, SPK2 and SPK3, are used as control sources.…”

Analysis and Optimal Condition of the Rear‐Sound‐Aided Control Source in Active Noise Control

“…The implementation has shown to be of lower cost and at the same time better control performance. This has been confirmed by experiments in both adaptive and robust control setups [2,3]. A welcome side effect was a lower controller gain and driving signals for the used loudspeakers [3,4], which enables the usage of lower power loudspeakers.…”

“…This has been confirmed by experiments in both adaptive and robust control setups [2,3]. A welcome side effect was a lower controller gain and driving signals for the used loudspeakers [3,4], which enables the usage of lower power loudspeakers. The advantage of the Swinbanks' source has been theoretically proven for a practical setting on the duct length and loudspeaker locations [5,6].…”