L. de Oliveira, Active Sound Quality Control: Design Tools and Automotive Applications, 2009

Abstract

As beings that rely strongly on their visual sense, people often take the role of sound for granted in their daily lives; even though acoustic communication is one of the fundamental prerequisites for the existence of human society. The level of noise is directly linked to our quality of living and, therefore, is of major concern. See for example, the various projects financed by the EU in the past years, which are related to the analysis and control of noise generated by human activity. The work presented in this thesis is related to the control of noise generated by vehicles and transmitted to its interior, affecting drivers and occupants. Not only noise reduction is pursued, but rather an improvement on the appreciation of the perceived noise by the occupants. Design strategies are presented, in order to cope with the recent challenges imposed by the use of smart-materials. The use of such technologies allows engineers to overcome limitations imposed by standard passive treatments (rubber mounts, textile trimming, etc.), however, poses a challenge for the standard design procedures. The first requirement, therefore, is to assess the efficiency of such smart solutions, taking human perception into account, e.g. by means of psychoacoustic metrics. A further step involves the design of dedicated control schemes for sound quality improvement. This thesis proposes simulation procedures for the design and optimization of vibro-acoustic systems and their embedded controllers. Simulation and experimental validation of passive and optimal active systems are reported, which attests the added value of the proposed design procedure. Also, a novel active sound quality controller is presented. This adaptive scheme is capable of equalizing, rather than only reducing, selected harmonic components of the engine sound.

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Order Code

Code: 09D07