Near-field Acoustical Holography - a new sensor concept for methods of active noise reduction

近场声全息术 - 用于主动降噪方法的新传感器概念

• 批准号: 527249322
• 负责人: Dr.-Ing. Steffen Ungnad
• 金额: --
• 依托单位: Professur für Mechatronik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/527249322?language=en
• 关键词: Near; field; Acoustical; Holography; new

The research hypothesis of the project comprises the development process of a sensor principle based on near-field acoustical holography for active noise reduction systems with structural actuators. The main objective is to extend sensor principles from the field of active noise and vibration control by inverse methods for sound field reconstruction. In particular, the influence of the inverse projection of sound field quantities on the stability of adaptive signal processing will be investigated. Compared to already existing approaches, an extension of the scientific knowledge is expected. The reason for this is that the use of acoustic sensors in conjunction with modern inverse acoustics methods enables non-contact observability of the sound field quantities proportional to the sound power in the near-field of arbitrarily shaped structures. Consequently, problems are avoided which arise because structural sensors such as accelerometers cannot be fixed as required. With near-field acoustical holography, a method is chosen which avoids costly measurements of transfer functions between sensor groups. For this purpose, only acoustic models are used, which results in lower uncertainties with respect to the model quality compared to the use of vibroacoustic models. Experiments are carried out in a transmission test facility, first on structural components that can be described analytically and then on complex structural components in the frequency range up to 1 kHz. This frequency range is typical for active noise reduction methods as a complement to passive measures, which are more effective at higher frequencies. Under free-field conditions, the Fourier transform-based near-field acoustical holography serves in the first step as a sensing principle for active noise reduction on a simply supported plate. With the relationship between the Fourier transform of the particle velocity on the plate surface and the directivity pattern of the radiated sound pressure into the far-field, the minimization of the radiated sound power is achieved. With the knowledge gained about the fundamental effects of inverse sound field reconstruction methods as a sensor principle on methods of active sound reduction, the experimental extension of the method to components with more complicated geometries will be carried out. The basic principles for the application of the investigated concept to cavities such as car or aircraft cabins are also to be developed. Therefore, in the last project phase the extension of the near-field acoustical holography-based sensor principle to sound fields in rooms is carried out by introducing reflection surfaces. Finally, comparisons will be made with conventional sensor principles for active sound reduction.

该项目的研究假设包括基于近场声全息的传感器原理的开发过程，用于具有结构致动器的主动降噪系统。主要目的是通过声场重建的逆方法从有源噪声和振动控制领域扩展传感器原理。特别是，声场量的逆投影对自适应信号处理的稳定性的影响将被研究。与现有的方法相比，科学知识的扩展是值得期待的。其原因在于，结合现代逆声学方法使用声学传感器能够实现与任意形状结构的近场中的声功率成比例的声场量的非接触式可观测性。因此，避免了由于诸如加速度计的结构传感器不能按要求固定而产生的问题。对于近场声全息，选择了一种方法，该方法避免了传感器组之间的传递函数的昂贵测量。为此，仅使用声学模型，与使用振动声学模型相比，这导致关于模型质量的更低的不确定性。实验在传输测试设备中进行，首先在可以解析描述的结构部件上进行，然后在频率范围高达1 kHz的复杂结构部件上进行。该频率范围通常用于主动降噪方法，作为对被动措施的补充，被动措施在较高频率下更有效。在自由场条件下，基于傅里叶变换的近场声全息作为一个简单的支持板上的主动降噪的传感原理的第一步。利用平板表面质点速度的傅里叶变换与辐射声压向远场方向图之间的关系，实现了辐射声功率的最小化。随着知识获得的基本影响的逆声场重建方法作为传感器的原则上的方法，主动降噪，该方法的实验扩展到更复杂的几何形状的组件将进行。还将开发将所研究的概念应用于诸如汽车或飞机客舱之类的空腔的基本原理。因此，在项目的最后阶段，通过引入反射表面，将基于近场声全息的传感器原理扩展到房间内的声场。最后，将与传统的传感器原理进行比较，主动降噪。