共查询到20条相似文献,搜索用时 171 毫秒
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提出了基于光学相干测振(optical coherence vibrometer, OCV)系统的微悬臂梁缺陷检测方法。自搭建的OCV系统最大振动位移量程、最大振动频率分别为2.574 mm和138.5 kHz,应用该系统对含缺陷微悬臂梁-附加质量块耦合结构进行振动测量获得其固有频率,并利用附加质量块对固有频率的影响特性实现了对缺陷的定位。在对系统采集到的干涉光谱信号处理的过程中,采用FFT(fast Fourier transform, FFT)+ FT(Fourier transform, FT)细化频谱校正算法进行误差校正,精度可提高1 000倍以上,使系统实现纳米量级的位移测量。实验结果表明,该方法能够有效识别微悬臂梁的缺陷位置,为微小型结构的缺陷检测提供了一种新的方法,同时拓展了光学相干测振技术在工程结构无损检测的应用。 相似文献
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利用磁耦合双光栅法动态测量了材料的弹性模量,采用电磁能非接触耦合样品激振,激光光拍法微振动非接触检测,使测试样品处于完全自由振动状态,通过激光光拍微弱振动位移测量了样品的固有频率,再通过测量几何尺寸和质量即可计算出样品的弹性模量. 相似文献
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为了对光学遥感卫星中飞轮微振动带来的成像像移进行精确预估,研究了飞轮微振动对成像影响的相关机理,建立了理论分析模型,搭建了高仿真度实验测量平台.研究微振动对成像影响机理,构建从飞轮扰振特性到成像像移之间的传递函数表达式,理论证明了谐波特性和模态特性是飞轮微振动对成像像移影响的两大重要特性.搭建高仿真度的实验平台对微振动影响下的图像像移进行精确测量.对比理论模型分析所得像移和实验测量数据,分析两者结果不一致产生的原因.结果表明:理论与测量的像移结果中谐波特性非常一致,两者具有几乎一致的典型的谐波因子;模态特性在低频段具有较高一致性,中低频段误差在8%以内. 相似文献
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本文提出了一种采用迈克尔逊干涉仪方法测量压电振子表面振动位移分布的简单方法。当其中一支光路引入一低频相位调制,可使测量结果不受环境机械振动和声噪声的干扰(包括带动微动台移动的马达机械振动和声噪声),因而可进行一维自动测量。当自动测量时,位移振幅一般需大于0.1A,当进行定点精密绝对测量时,最小可测位移为5×10~(-2)-5×10~(-3)A,最后给出了几种压电振子的测量结果。 相似文献
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Yan Li Shangchun Fan Zhanshe Guo Jing Li Le Cao 《Journal of sound and vibration》2012,331(20):4417-4424
In this paper, frequency measurement methods of resonant vibratory gyroscopes are studied. First, the working principle and dynamic output characteristics of the resonant vibratory gyroscope are introduced, which provide a theoretical analysis base to analyze the dynamic frequency output characteristic of the resonant vibratory gyroscope. Moreover, some relevant frequency measurement methods are introduced, a frequency measurement method based on dynamic output characteristics has been proposed for the purpose of investigating the modulated output signal of resonant vibratory gyroscopes. Finally, in order to verify the feasibility of the proposed frequency measurement method, resonator oscillator and dynamic frequency measurement experiments of the resonant vibratory gyroscopes are built. It is concluded from the resonator oscillator result that the designed and observed resonant frequency of the resonator have a good match, which shows the design of resonator oscillator is feasible. It is concluded from the dynamic frequency measurement result that correlation coefficient of output fitted curve is 99.95%, and the output characteristic of the gyroscope is linear frequency output, which shows the effectiveness of the proposed frequency measurement method. 相似文献
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微结构特性的光学测试平台 总被引:10,自引:0,他引:10
微结构是微机电系统的基本元件,其几何尺寸、运动特性、材料及力学特性直接影响微机电系统的整体性能。提出一种将计算机微视觉、米劳显微干涉、频闪成像和激光多普勒测振等技术充分融合的微结构静态和动态特性的光学测试平台,分别对微谐振器的平面和离面周期运动特性和微机械扭转镜的离面瞬时运动特性进行测试研究。实验结果表明,利用计算机微视觉和频闪成像技术能够实观微结构的平面位移、运动相位及喈振频率等周期运动参量的测试.位移的重复精度为30nm;利用显微干涉和频闪成像技术可实现微结构的离面位移及表面扭曲等周期运动参量的测试.位移的重复精度为3nm;激光多普勒测振技术具有在频域上对微结构瞬态运动进行分析的优点.是时域上周期运动测试的重要补充。 相似文献
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The aim of this paper is to investigate the dynamic characteristics of a valve-less micropump. A dynamic mathematical model of the micropump based on a hydraulic analogue system and a simulation method using AMESim software are developed. By using the finite-element analysis method, the static analysis of the diaphragm is carried out to obtain the maximum deflection and volumetric displacement. Dynamic characteristics of the valve-less micropump under different excitation voltages and frequencies are simulated and tested. Because of the discrepancy between simulation results and experimental data at frequencies other than the natural frequency, the revised model for the diaphragm maximum volumetric displacement is presented. Comparison between the simulation results based on the revised model and experimental data shows that the dynamic mathematical model based on the hydraulic analogue system is capable of predicting dynamic characteristics of the valve-less micropump at any excitation voltage and frequency. 相似文献
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为了实现超低频振动速度测量, 提出补偿其幅频特性的小波神经网络方法.该方法以振动速度传感器动态实验数据为基础, 通过小波神经网络训练来确定传感器幅频特性补偿网络.介绍振动速度传感器幅频特性补偿原理, 分析网络的拓扑结构, 给出网络参数训练和初始化方法.采用引入动量项的最速下降法训练网络权值、尺度因子和平移因子, 将小波网络参数的初始化与小波类型、小波时频参数和学习样本等联系起来.结果表明, 采用小波神经网络进行振动速度传感器幅频特性补偿具有良好的鲁棒性,并能实现在线补偿,网络训练的速度和精度优于同等规模的BP网络,在测试领域有重要的实用价值.
关键词:
振动速度传感器
小波神经网络
幅频特性
补偿 相似文献
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激光陀螺抖动偏频优化研究 总被引:2,自引:1,他引:1
基于频率调制理论,分析、仿真计算了正弦抖动偏频和优化后的正弦抖动偏频条件下,激光陀螺输入-输出曲线的特点.结果表明:正弦抖动偏频时激光陀螺的输入-输出曲线在抖动频率的倍频点处存在着动态锁区,其宽度与激光陀螺静态锁区、抖动角振幅有关.采用优化后的正弦抖动偏频可以很好地克服动态锁区,大大提高激光陀螺输入-输出曲线的线性度.试验对比了正弦抖动偏频和优化后的正弦抖动偏频条件下激光陀螺的输出性能.试验结果表明:采用优化后的正弦抖动偏频显著提高了陀螺准确度. 相似文献
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Peter Kitzing 《Journal of voice》1990,4(3)
Electroglottography (EGG) is a method to monitor the vibrations of the vocal folds by measuring the varying impedance to a weak alternating current through the tissues of the neck. The paper is an attempt to give a state-of-the-art report of how electroglottography is used in the clinic. It is based on a search of the pertinent literature was well as on an inquiry to 17 well known specialists in the field. The EGG techniques are described and limitations to the method are pointed out. Attempts to document voice quality by EGG are recognized and computerized methods to obtain information about vibratory perturbations and/or the vibratory frequency of the vocal folds are described. The author's personal conclusion is that the EGG signal is especially well suited for measurements of the glottal vibratory period. In the clinic such measurements are useful for periodicity analysis, as a basis for recording intonation contours, and to establish the characteristics of the voice fundamental frequency. 相似文献
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Young Cheol Huh 《Journal of sound and vibration》2011,330(15):3645-3665
While there have been several analytical studies to estimate the vibratory power of damaged structures, only a few attempts have been tried to identify the damage for practical implementations. In order to understand the characteristics of the vibratory power in damaged structures, it is necessary to trace the time histories of the instantaneous power in the vicinity of the damage. The spatial distribution of the vibratory power should also be investigated, and a proper damage index is required to diagnose the damage. In this paper, a practicable local damage detection method is proposed using the vibratory power estimated from the accelerations measured on the damaged beam structure. A new damage index is defined based on the proposed damage detection method and is applied to identify the structural damage. Numerical simulation and experiment are carried out on a beam to confirm the validity of the proposed method. In the experiments, the damage considered as an open crack such as slit inflicted on the top surface of the beam. Changes in the vibratory power of the damaged beam are investigated, and the results show that the proposed method identifies successfully the structural damage in the beam. 相似文献
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Dynamic characteristics of resonant gyroscopes study based on the Mathieu equation approximate solution 下载免费PDF全文
Dynamic characteristics of the resonant gyroscope are studied based on the Mathieu equation approximate solution in this paper.The Mathieu equation is used to analyze the parametric resonant characteristics and the approximate output of the resonant gyroscope.The method of small parameter perturbation is used to analyze the approximate solution of the Mathieu equation.The theoretical analysis and the numerical simulations show that the approximate solution of the Mathieu equation is close to the dynamic output characteristics of the resonant gyroscope.The experimental analysis shows that the theoretical curve and the experimental data processing results coincide perfectly,which means that the approximate solution of the Mathieu equation can present the dynamic output characteristic of the resonant gyroscope.The theoretical approach and the experimental results of the Mathieu equation approximate solution are obtained,which provides a reference for the robust design of the resonant gyroscope. 相似文献
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The vibrations generated by friction are responsible for various noises such as squealing, squeaking and chatter. Although these phenomena have been studied for a long time, it is not well-understood. In this study, an experimental and numerical study of friction-induced vibrations of a system composed of two beams in contact is proposed. The experimental system exhibits periodic steady state vibrations of different types. To model and understand this experimental vibratory phenomenon, complex eigenvalue and dynamic transient analyses are performed. In the linear complex eigenvalue analysis, flutter instability occurs via the coalescence of two eigenmodes of the system. This linear study provides an accurate value of the experimental frequency of vibration. To understand what happens physically during friction-induced instability, a dynamic transient analysis that takes account of the non-linear aspect of a frictional contact is performed. In this analysis, friction-induced instability is characterized by self-sustained vibrations and by stick, slip and separation zones occurring at the surface of the contact. The results stemming from this analysis show that good correlation between numerical and experimental vibrations can be obtained (in time and frequency domains). Moreover, time domain simulations permit understanding the physical phenomena involved in two different vibratory behaviours observed experimentally. 相似文献