2022 Fiscal Year Final Research Report
Development of Multi-Channel ANC Using Super-Directional Speakers for Seamless Silence in Indoor Environments
| Project/Area Number |
20K04540
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 21040:Control and system engineering-related
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| Research Institution | Nippon Institute of Technology |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | アクティブノイズコントローラ / パラメトリックスピーカ / 多チャネル制御 / 二次経路変動 |
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| Outline of Final Research Achievements |
ANC generates a control sound with the same amplitude and opposite phase as the noise, and actively cancels the noise. Most of the conventional methods can obtain an effective amount of silence suppression at the muffing control point, but noise increases at the non-control point due to the interference of in-phase sounds. Also, if the secondary path changes, the muffing operation will not be stable and cannot be used in a general indoor environment. In this research, we developed an ANC system using multi-channel super-directional speakers to solve these problems. In the proposed system, we suppressed the increase in sound pressure at uncontrolled points by taking advantage of the characteristics of the speaker. In addition, by constructing a simple secondary path estimation method and an inter-channel sound pressure control method, we clarified that it is possible to achieve stable noise reduction even when the indoor environment changes.
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| Free Research Field |
適応信号処理
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| Academic Significance and Societal Importance of the Research Achievements |
既存のANCは，特定の環境や様々な制約条件下に動作が限定されるため，公共施設やオフィス，一般家屋など，一般の人々が利用する環境への適用には至っていない。既存研究では一般的なスピーカを用いたシステムの他に超指向性スピーカを用いた先行研究が数種あるが，それらは単チャネルでの基礎研究が多く，実環境への適用には様々な課題が残る。本研究では超指向性スピーカを用いた多チャネル系を構築することで，既存ANCの問題点である非制御点での騒音増大及び二次経路変動によるシステムの不安定化を効果的に解決した。実用化には幾つかの解決すべき項目が残るものの，使用環境の制約が少ない一般性を持つ騒音除去システムを実現した。
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