一种作动器位移参数的检测方法

根据校准作动器位移量的要求,以位移测量仪作为长度标准器,配备了3种专用检测附件,组成作动器位移量测量装置.经试验分析,该装置测量准确度能够满足作动器位移量的测量要求,并且便于在现场进行装配.使用该装置,对作动器进行多次测量,并对测量结果进行不确定度分析,其测量结果表明,动作器位移量测量装置的工作原理及性能,能够满足各种作动器的位移量测量要求.     

基于耦合模型的人工中耳压电振子设计

利用中耳与压电振子的耦合力学模型,研究设计人工中耳压电振子。该力学模型基于一无任何听力损伤病史的成年志愿者的左耳,利用CT扫描和逆向成型技术建成模。模型的可靠性通过镫骨底板的位移计算结果与国外文献实验测得数据进行对比加以验证。最终设计的压电振子采取悬浮结构,由绑定装置、压电叠堆及质量块所组成,仅需简单的手术便可直接将其植入在砧骨长突上,且只需要10.5 Vrms的驱动电压便可以对镫骨激起相当于鼓膜处100 dB声压激励的振幅。     

磁致伸缩作动器的设计与性能分析

在分析超磁致伸缩材料特性的基础上设计了一种微位移作动器．通过有限元分析，对作动器的结构进行优化，得到均匀的偏置磁场和激励磁场；设计了预压力加栽结构和强制冷却结构．对该作动器的动、静态性能进行了测试，结果表明：作动器基本上工作在线性区域内，其位移伸缩量大，低频动态性能较好，高频谐波分量影响较小，相位延迟较小，同时也证明了对作动器的磁场分析和结构优化是正确的．     

轮带系统横向振动变结构控制方法

针对由主从动轮、作动器及皮带构成的典型轮带系统模型,皮带横向振动与主、从动轮及作动器振动相耦合,其横向位移受主、从动轮及作动器影响,给出皮带在谐波激励下横向振动位移精确表达式,利用变结构理论,采用指数趋近律设计出有效控制力以控制张紧臂方向,从而抑制皮带横向振动。在初始条件和与激励作用下,利用Matlab进行数值仿真。结果表明：在谐波激励下,皮带横向振动位移得到有效抑制,验证控制力的有效性。     

航海船舶多维振动主动控制研究

采用基于并联机构和电磁作动器的多维振动主动控制装置,实现了对船舶航行中面临的多维低频振动衰减。对振动控制装置进行了结 构设计、系统控制模型分析和控制算法研究,并制作样机进行了实验研究。样机试验结果表明,该多维减振装置能够实现船舶多维低频振动主 动控制。     

新型人工中耳压电振子设计

提出利用压电叠堆作砧骨激励式人工中耳的振子,并利用中耳-压电叠堆耦合力学模型对该压电叠堆振子进行辅助设计。该模型基于一无任何听力损伤病史的成年志愿者的左耳,利用CT扫描和逆向成型技术建成。其可靠性通过与实验对比加以验证。最终设计的压电振子只需要10.5 V的有效驱动电压,便可以对镫骨激起相当于鼓膜处90 dB声压激励的振幅。该振子在频率为1 kHz的单伏电压驱动工况下,能耗仅为0.03 mW,满足人工中耳低电压、低能耗的要求。     

智能微位移主动隔振控制系统的研究

针对精密加工设备的微位移隔振问题,设计了一种以压电陶瓷为作动器的新型智能微位移主动隔振控制系统,在NI PXI数据采集系统和BK激振器的基础上,搭建了该系统的实验平台,提出将有源噪声控制理论应用到微位移振动的主动控制中,开发了在Lab VIEW软件环境下整个系统的数据采集和F-XLMS控制算法的控制程序,分别在正弦、扫频和随机激励信号下进行微位移主动隔振实验研究,结果表明三种激励信号受控后的振动位移大幅度降低,验证了该系统对微位移主动隔振的有效性,为精密仪器、微纳米设备的微位移智能主动隔振系统设计奠定了基础。     

振子及其耦合条件对圆窗激励式人工中耳性能影响的数值研究

为研究振子及其耦合条件对圆窗激励式人工中耳植入性能的影响,建立了包括振子和隔膜在内的人耳有限元模型。该模型基于一无任何听力损伤病史的成年志愿者右耳,采用CT扫描和逆向成型技术建立而成,通过与相关文献的实验数据比对验证了模型的可靠性。基于该模型,分析了圆窗上的初始预压力、振子和隔膜的设计参数变化对振子听力性能的影响。结果表明:振子横截面积越大,其对耳蜗的激励效果越差;隔膜的引入有利于提高振子的激振性能,在该研究范围内,较小的隔膜杨氏模量和厚度有利于提升振子的激振性能;振子质量的增加会恶化振子在高频段的植入性能;在圆窗上施加的初始预压力能够提高中高频段上对耳蜗的激振效果。     

拉索-磁致伸缩作动器系统PID控制仿真分析

拉索的大幅振动给斜拉桥安全运营带来威胁,利用磁致伸缩作动器施加轴向控制力抑制拉索横向振动是一种可行的方法。首先建立磁致伸缩作动器动力学模型,得到了该作动器力-位移传递函数,然后提出拉索-磁致伸缩作动器系统PID控制算法,根据拉索振动幅度大小通过调节PID控制参数,来施加轴向控制力,达到对拉索的控制效果。最后针对自由振动、简谐激励、随机激励三种情况用PID控制算法对拉索-磁致伸缩作动器系统进行了拉索控制效果仿真分析。研究表明,PID控制算法对拉索振动具有很好的控制效果。     

振动控制中压电作动器非线性的补偿方法研究

在周期振动的自适应控制中,压电作动器的非线性特性会产生高次谐波,激发高阶模态振动。为抑制压电作动器的高次谐波激励,同时结合自适应振动控制的特点,提出一种新的作动器非线性补偿方法。该方法将作动器的非线性与结构的动态特性部分融合,用正交多项式从输入输出信号中拟合静态非线性及其逆变换,计算过程简单,数值稳定性高。在控制通道中,通过逆变换对控制信号进行预处理,使得补偿后的输入输出具有线性系统的特征,而输入输出之间的相位差完全由自适应算法进行补偿。实验结果表明,所给出的补偿方法能够抑制高次谐波,并改善了振动控制效果。     

A new electromagnetic hearing aid using lightweight coils to vibrate the ossicles

As the first stage in the development of a noninvasive electromagnetic hearing aid, we made a new transducer that generates a high-excitation force to vibrate ossicles via the tympanic membrane. This transducer consists of a core, driving and induction coils, a rare-earth magnet, and a vibrator coil. We designed the core, the driving and induction coils, and the magnet so as to generate the greatest excitation force possible when installed in the external ear canal of humans. With regard to the vibrator coil, which was attached to the center of the tympanic membrane to vibrate the ossicles, we determined its optimal mass, position, and shape both by finite-element method (FEM) analysis and by experiments using an artificial middle ear. A prototype of the optimally designed transducer can generate an excitation force of more than 95 dB sound pressure level (SPL) in terms of sound pressure at frequencies between 0.1 and 10 kHz. This result indicates that the transducer developed in this study can be used to treat patients with a hearing loss up to 70 dB hearing level (HL).     

人工中耳悬浮式压电振子的优化设计

为了优化人工中耳悬浮式压电振子的植入效果,设计了一种位移放大结构用于改善振子的输出特性。首先采用微CT扫描和逆向成型技术建立了包括外耳道、中耳和简化耳蜗的人耳有限元模型,通过与文献的实验数据比对验证模型的有效性。然后建立人耳与悬浮振子的耦合力学模型,通过有限元的耦合场分析研究加入位移放大结构前后的人工中耳植入效果。研究结果表明,采用位移放大结构后,振子于中高频段的等效声压级得到明显提升,可以有效降低压电振子的功耗。     

In vitro release kinetics of gentamycin from a sodium hyaluronate gel delivery system suitable for the treatment of peripheral vestibular disease

For certain patients who experience intense vertigo arising from unilateral vestibular lesions, the primary therapy is a vestibular nerve section, an intracranial surgical procedure. One alternative to this treatment is therapeutic ablation of vestibular function on the unaffected side using an ototoxic agent. We prepared a biodegradable sustained-release gel delivery system using sodium hyaluronate that can be administered into the middle ear using only a local anesthetic. The gel contains gentamycin sulfate, the ototoxic agent of choice for treatment of unilateral vestibulopathy, and it exhibits diffusion-controlled release of the drug over a period of hours. The released gentamycin could then diffuse into the inner ear through the round membrane. This represents an important advance over previous formulations, which used only gentamycin sulfate solutions, in that it should allow more careful control of the dose, it should reduce loss of the drug from the middle ear site, and it should maintain intimate contact with the round membrane. By carefully controlling the dose, it should be possible to inhibit vestibular function while minimizing hearing loss. Herein we describe the in vitro release kinetics of gentamycin sulfate from sodium hyaluronate gels and find that the system obeys Fickian behavior.     

In Vitro Release Kinetics of Gentamycin from a Sodium Hyaluronate Gel Delivery System Suitable for the Treatment of Peripheral Vestibular Disease

For certain patients who experience intense vertigo arising from unilateral vestibular lesions, the primary therapy is a vestibular nerve section, an intracranial surgical procedure. One alternative to this treatment is therapeutic ablation of vestibular function on the unaffected side using an ototoxic agent. We prepared a biodegradable sustained-release gel delivery system using sodium hyaluronate that can be administered into the middle ear using only a local anesthetic. The gel contains gentamycin sulfate, the ototoxic agent of choice for treatment of unilateral vestibulopathy, and it exhibits diffusion-controlled release of the drug over a period of hours. The released gentamycin could then diffuse into the inner ear through the round membrane. This represents an important advance over previous formulations, which used only gentamycin sulfate solutions, in that it should allow more careful control of the dose, it should reduce loss of the drug from the middle ear site, and it should maintain intimate contact with the round membrane. By carefully controlling the dose, it should be possible to inhibit vestibular function while minimizing hearing loss. Herein we describe the in vitro release kinetics of gentamycin sulfate from sodium hyaluronate gels and find that the system obeys Fickian behavior.     

外中耳传声对响度感知影响的数值研究

现有响度模型主要通过滤波器组在传递特性上模拟人耳感声特性,未能真实反映人耳的生理结构。基于新鲜人体颞骨标本微CT扫描影像,通过逆向成型技术及有限元法建立了基于真实生理结构的人耳模型,并基于该模型,研究外、中耳与人耳响度感知的关系。该模型主要包括耳道和中耳两个部分,通过镫骨、鼓膜脐部位移响应,镫骨速度传递函数及鼓膜处声压级对模型进行可靠性验证。最终,基于该模型,系统分析了经过外、中耳传声,传递到镫骨的镫骨底板输出位移、速度、能量与响度感知听阀曲线的关系。研究结果表明,镫骨底板输出的等速曲线及等能量曲线在中、高频段内与听阀曲线较接近,可以用于近似评估人耳在该频段内的响度感知效果。     

Biomaterials for ossicular chain reconstruction. A review

This review gives a survey of biomaterials used for ossicular chain reconstruction. The survey is focussed on application, biophysical requirements, properties and goals for future developments. The implantation site middle ear differs from others due to aeration and potential bacterial colonization. As a consequence, implant materials must exhibit excellent biocompatibility, biostabilty and sound conducting properties. In vitro and in vivo biocompatibility investigations and clinical observations determine the choice of material. Additionally the implants must provide the possibilty of intraoperative shaping or should be available in different variations in order to allow reconstruction appropriate to the individual conditions. Ceramics, metals and plastics are materials in current use. Based on thorough experimental and long term clinical experiences, the bioinert aluminum oxide is favorable amoung the ceramics. Bioactive ceramics may have minor biostability and the risk of fixation to surrounding bone which impairs sound conduction. This is also true for hydroxyapatite although biodegradation occurs only rarely. Today, titanium is the metal best established in middle ear implantation, reflected by excellent biocompatibility in vitro and in vivo, and good clinical results. Titanium is preferred by many surgeons, considering that sound transmission properties are mainly dependent on the implant weight. In stapes surgery, when the implant has direct contact to inner fluids, gold was accused to cause granuloma formation with subsequent inner ear damage in selected cases. In frequent past and present use, plastics (porous polyethylene and teflon) have proven to be of limited value in ossicular chain replacement because of high extrusion rates and the observation of material desintegration and bacterial colonization. In order to individually manage the pathological conditions in the middle ear, the implant design is of crucial importance. It is dependent on the ossicle to be replaced and the implant material. Future investigations have to minimize implant extrusions possibly by modifying and improving implant surfaces.     

The use of a SQUID magnetometer for middle ear research

A new technique is described for the measurement of vibrations in the temporal bones of an isolated middle ear. The precise recording of vibrations in the middle ear is of importance for the construction and improvement of a middle ear prosthesis.¹ The method of measurement is based on a transformation of mechanical vibrations into magnetic flux variations. This is performed by attaching a small piece of permanent magnetic material to the eardrum or middle ear ossicles. The magnetic flux variations caused by vibrations of the eardrum or ossicles during application of sound can be measured by means of a SQUID magnetometer.Measurements showed that it is possible to measure vibratory displacement amplitudes of the eardrum down to about 10^?10 m in a frequency range between 200 Hz and 10 kHz, although the acoustical and magnetometer conditions were not optimal. The method offers several advantages compared to already existing methods.^2–5,8     

Some potential applications of engineering science disciplines in hearing mechanism research

The field of Auditory Studies available to treatment by techniques common in Engineering Science is described under three headings. The first is the Fluid Dynamic Aspects of Cochlea Behaviour in which necessary simplification of the describing equations is achieved with the guidance of dynamic similarity experiments. The second concerns the relationship of neural excitation to basilor membrane displacement function, the terminal point for hydrodynamic analyses. Currently it is envisaged that the formulation of evaluated hypotheses of hair cell deformation will represent the most useful contribution. The third heading relates to middle ear function where an ascending series of kinematic, static and dynamic analyses will give rise to data for middle ear prosthesis re-design and novel comment on middle ear muscle function.