【作者】 王庆生；

【导师】 饶柱石；

【作者基本信息】 上海交通大学 ， 机械设计及理论， 2010， 博士

【摘要】 声源定位在工程应用中具有重要的价值。常见的声源定位一般是通过若干个传声器单元组成的传声器阵列来实现的,各传声器单元对声激励产生响应而生成多个时间序列,并将其送至实现定位算法的运算单元中从而计算得到声源的位置。通常,传声器阵列中的各传声器单元之间均独立而不相互耦合,为获得足够的声场信息,必须保证传声器阵列具有一定的单元个数,此外,为保证定位的精度,传声器单元的间距也往往远大于传声器单元的距离精度,也即其间距要远大于系统采样周期与声波在介质中的传播速度的乘积。因此,传声器阵列的整体尺寸将比较庞大,结构也较为复杂。而在一些特殊的应用领域,如微型运载工具用高精度微型声纳、具有声源定位功能的感向助听器等中,需要声定位结构在保证定位精度的前提下,兼具微型化的特征。此外,在水声学领域中,常使用拖曳阵等阵列形式组成声纳系统,利用声波对海洋中存在的水下目标进行探测、识别和定位。为提高其测向精度,需要组成大的水听器基阵并加大其布置的间隔,因而基阵尺寸将比较庞大,在航行中容易遭到损坏,且需要安装相当多的航向感应器来修正基阵在航行中存在的较大的曲率。声纳基阵庞大的尺度带来的这些缺点提高了声纳系统实际运用的难度,因此减小基阵尺度对于声纳系统的应用具有重要的意义。上述应用领域对声定位系统的结构提出了特殊的要求,因而须寻找新的技术来满足使用需求。近年来,基于对各种动物,尤其是对具有优异声源定位能力的奥米亚棕寄生蝇等微型生物的听觉定向机理的探索及其仿生学研究,将有可能为上述应用领域提供较好的解决方案。本文的研究就是在这种背景下展开的。奥米亚棕蝇等微型动物的耳间距十分微小,却能凭借其构造独特的声感应系统对外界入射声源的方位作出准确的判断。这种优异的定位能力得益于其双耳间角质皮膜结构的一种机械耦合放大效应。本文的研究对象是奥米亚棕蝇的听觉系统及相应的仿生力学模型及实验模型,研究的目的是借鉴奥米亚棕蝇听觉系统的声定位机制,研究并提出一种新的仿生三维声定位方法,建立相应的力学模型和实验室模型,通过深入的理论和实验研究,最终建立一套仿生三维声感应结构的设计理论与方法体系。在此基础上,设计制造实验室模型装置并对其进行实验验证。通过本课题研究,为具有自主知识产权的微型仿生声传感与定位系统的研发和应用奠定基础。对于设计仿生声感应结构来说,利用何种定向机制来完成对声源方向角的估算,以及仿生结构本身应如何选取适当的力学参数来与所采取的定位机制相对应,是应当解决的首要问题。因此,本文在前人对奥米亚棕寄生蝇所进行的解剖学及生理学研究基础上,对其听觉器官的声定向机理及动力学特性进行了较为深入的分析研究,分析探讨了设计仿生声感应结构时可采用的定位机制,即通过测量耦合振膜结构两侧响应幅值差及相位差等信息来对声源方向角进行估测,并探讨了模型力学参数对于系统响应的影响。通过对仿生声感应结构可采用的定向机制所进行的探讨,提出了可用于三维空间内对声源方向角进行感测的仿生声感应结构的力学模型,并对该力学模型的动力学特性及其在不同的频率与方向的入射声激励下的响应特性进行了相应的分析和讨论,并分析了力学模型中关键参数对结构响应的影响及耦合结构对声激励幅值差和相位差的放大作用。分析结果表明,声激励的入射方向同三个振膜的响应之间存在着特定的关系,由此提出了一种通过检测并分析三个振膜的响应状况以估测声激励入射角度的方法。在前述理论分析的基础上,本文提出了仿生声感应结构的设计方案,该方案利用弹簧和绕固定轴旋转的刚性杆实现了振膜之间振动响应的耦合。随后,导出了该声感应结构的振动微分方程,分析了实际结构参数与力学模型参数之间的对应关系以及仿生声感应结构适合的频带范围及其灵敏度,为加工仿生三维声感应结构的实验室模型提供了依据。为验证上述理论分析方法,加工了实验模型,建立了相应的测试系统,并进行了实验。实验所测数据和根据实测数据进行的分析计算结果表明,本文的建模方法和理论分析是正确的。更多还原

【Abstract】 Sound source localization is always of great value in many engineering applications. In these types of localization appliances, several microphone transducers are usually involved in the localization structures. Each of the time-domain response of these microphones under the incident sound stimulus is determined individually and sent to the arithmetic-logic sections immediately by which the localization systems could find out positions of the sound sources subsequently. The transducers used in microphone array are usually independent of each other, so the microphone array should have enough microphone transducers in order to obtain sufficient acoustic field information. Additionally, the minimum element spacing of the microphone array should be much greater than the distance accuray in order to ensure positioning accuracy, in other words, the minimum element spacing of the microphone array should be much larger than the product of sampling interval and sound velocity in the acoustic propagation medium. Therefore, these appliances always consist of many components, and the looseness of structures of them may narrow their practical applications. In some special application situations, such as micro sonar system used in miniature transportation vehicles and hearing aids capable of determining direction of the acoustic excitation, the transducer system should be designed to accomplish the purpose of localizing the sound source by a relatively compact structure. These types of application situations demand new technologies to satisfy the requirements. In recent years, studies on orientation mechanisms of the auditory systems and research of bionic structures of subminiature creatures, especially of the parasitoid fly Ormia Ochracea which has a remarkable ability to detect the direction of the incident sound stimulus despite of its tiny body size, may provide preferable solutions for these types of applications. This present dissertation was completed under this background.The acoustic sensory organs of the parasitoid Ormia Ochracea, the mechanical and the experimental of bionic acoustic sensing device are taken as the research object to find feasible orientation mechanisms which can be used for reference to design reliable and practical acoustic sensing devices and put forward the estimating method of direction angles of sound stimulus.Orientation mechanisms for the estimation of direction angles of sound stimulus and parameter selection of mechanical model are very important for designing the bionic acoustic sensing device. Based on the previous research on anatomy and physiology of the parasitoid fly Ormia Ochracea, the orientation mechanisms and dynamic characteristics of its acoustic sensory organs are discussed further, which are beneficial for bionics research on acoustic sensing devices.On the basis of this discusses on the orientation mechanisms of the biomimetic structure, the mechanical models for the purpose of estimating the direction angles of sound stimulus in the plane or in half-space. The vibration performances and response characteristics under different incident frequencies or incident angles are analyzed respectively. The analysis of this structure’s dynamic behavior shows that the incident angles of the sound have special relationship to the responses of this instrument, and the incident angles can be estimated by detecting and processing the vibration responses of the three elastic diaphragms.According to the localization mechanism and theoretical analyses mentioned above, an acoustic sensing device used mechanically coupled diaphragms is designed, which consists of three springs and rigid bars to accomplish the purpose of coupling between vibration responses of the diaphragms. Vibration differential equations of the acoustic sensing device and the relationship of parameters of the experimental structure and parameters of the mechanical model are established and the sensitivity of vibration responses to strength of the sound stimulus is analyzed simultaneously, these works provide the basis for the manufacture of experimental acoustic sensing device.In the last part of this paper, experiments on bionic acoustic sensing device are conducted after the test system has been established. The measured data and the analyses based on the measured data demonstrate that the modeling methods and theoretical study in this dissertation are correct.更多还原