Fiber Optic 3-D Space Piezoelectric Accelerometer and its Antinoise Technology

The mechanical structure of piezoelectric accelerometer is designed, and the operation equations on X , Y , and Z axes are deduced. The test results of 3 D frequency response are given. Noise disturbances are effectively eliminated by using fiber optic transmission and synchronous detection.

Measurement of six degree-of-freedom ground motion by using eight accelerometers

A new integrated measuring system with eight force-balance accelerometers is proposed to obtain a direct measurement of six degree-of freedom （DOF） ground motions, including three rotational and three actual translational acceleration components without gyroscopes. In the proposed measuring system, the relationship between the output from eight force-balance accelerometer and the six DOF motion of the measuring system under an earthquake are described by differential equations. These equations are derived from the positions and directions of the eight force-balance accelerometers in the measuring system. The third-order Runge-Kutta algorithm is used to guarantee the accuracy of the numerical calculation. All the algorithms used to compute the six DOF components of the ground motion are implemented in a real-time in Digital Signal Processor （DSP）. The distortion of the measured results caused by position and direction errors of the accelerometers in the measuring system are reduced by multiplying a compensation coefficient C to the output and subtracting static zero drift from the measured results, respectively.

Effect of annealing temperature on the microstructure and optoelectrical properties of ZnO thin films and their application in self-powered accelerometers

This paper reports a piezoelectric nanogenerator(NG) with a thickness of approximately 80 μm for miniaturized self-powered acceleration sensors. To deposit the piezoelectric zinc oxide(ZnO) thin film, a magnetron sputtering machine was used. Polymethyl methacrylate(PMMA) and aluminum-doped zinc oxide(AZO) were used as the insulating layer and the top electrode of the NG, respectively. The experimental results show that the ZnO thin films annealed at 150℃ exhibited the highest crystallinity among the prepared films and an optical band gap of 3.24 eV. The NG fabricated with an AZO/PMMA/ZnO/stainless steel configuration exhibited a higher output voltage than the device with an AZO/ZnO/PMMA/stainless steel configuration. In addition, the annealing temperature affected the open-circuit voltage of the NGs;the output voltage reached 3.81 V when the annealing temperature was 150℃. The open-circuit voltage of the prepared self-powered accelerometer increased linearly with acceleration. In addition, the small NG-based accelerometer, which exhibited excellent fatigue resistance, can be used for acceleration measurements of small and lightweight devices.

An aerosol deposition based MEMS piezoelectric accelerometer for low noise measurement

Potentially applied in low-noise applications such as structural health monitoring(SHM),a 1-axis piezoelectric MEMS accelerometer based on aerosol deposition is designed,fabricated,simulated,and measured in this study.It is a cantilever beam structure with a tip proof mass and PZT sensing layer.To figure out whether the design is suitable for SHM,working bandwidth and noise level are obtained via simulation.For the first time,we use aerosol deposition method to deposit thick PZT flm during the fabrication process to achieve high sensitivity.In performance measurement,we obtain the charge sensitivity,natural frequency,working bandwidth and noise equivalent acceleration of 22.74 pC/g,867.4 Hz,10-200 Hz(within±5%deviation)and 5.6μg/√Hz(at 20 Hz).To demonstrate its feasibility for real applications,vibrations of a fan are measured by our designed sensor and a commercial piezoelectric accelerometer,and the results match well with each other.Moreover,shaker vibration measurement with ADXL1001 indicates that the fabricated sensor has a much lower noise level.In the end,we show that our designed accelerometer has good performance compared to piezoelectric MEMS accelerometers in relevant studies and great potential for low-noise applications compared to low-noise capacitive MEMS accelerometers.

A polymeric piezoelectric MEMS accelerometer with high sensitivity,low noise density,and an innovative manufacturing approach

The piezoelectric coupling principle is widely used(along with capacitive coupling and piezoresistive coupling)for MEMS accelerometers.Piezoelectric MEMS accelerometers are used primarily for vibration monitoring.Polymer piezoelectric MEMS accelerometers offer the merits of heavy-metal-free structure material and simple microfabrication flow.More importantly,polymeric piezoelectric MEMS accelerometers may be the basis of novel applications,such as fully organic inertial sensing microsystems using polymer sensors and organic integrated circuits.This paper presents a novel polymer piezoelectric MEMS accelerometer design using PVDF films.A simple and rapid microfabrication flow based on laser micromachining of thin films and 3D stereolithography was developed to fabricate three samples of this design.During proof-of-concept experiments,the design achieved a sensitivity of 21.82 pC/g(equivalent open-circuit voltage sensitivity:126.32 mV/g),a 5%flat band of 58.5 Hz,and a noise density of 6.02µg/√Hz.Thus,this design rivals state-of-the-art PZT-based counterparts in charge sensitivity and noise density,and it surpasses the performance capabilities of several commercial MEMS accelerometers.Moreover,this design has a 10-times smaller device area and a 4-times larger flat band than previous state-of-the-art organic piezoelectric MEMS accelerometers.These experimentally validated performance metrics demonstrate the promising application potential of the polymeric piezoelectric MEMS accelerometer design presented in this article.

基于硅酸镓镧高温压电剪切加速度计的设计与制备

随着航空航天、原子能技术、汽车电子、冶金与石油化工等工业的迅猛发展,迫切需要能够在高温环境下对振动、压力及噪声等进行监测的传感器。本文设计并制备了基于硅酸镓镧(LGS)压电单晶材料的压电加速度传感器。实验结果表明,该传感器的谐振频率约为3 kHz,在常温~800℃,工作频率为80~1 000 Hz范围内,传感器的电荷灵敏度保持稳定,平均值为0.081 pC/g_(n)。该传感器能在800℃高温下稳定工作。

压电加速度传感器电激励自校准方法研究

为解决加速度计难以实现定期校准、校准成本高、难以满足长期工作需求等问题,对带有驱动端口的压电加速度传感器的自校准方法进行了研究。利用振动台校准方法以及基于驱动压电元件的逆压电效应,通过对传感器驱动端口电激励可实现驱动压电元件的转换灵敏度测试,并实现加速度计的现场原位校准。将校准结果与振动台校准方法的校准结果进行对比,实验结果表明,在频率范围5~10000 Hz,自校准灵敏度结果与振动台灵敏度校准结果一致,误差在±2%以内,验证了该方法的有效性。

一种高精度测量IEPE加速度传感器的电路设计与应用

随着环境试验设备产业的快速发展,环境振动试验的需求日益增加,其中加速度的测量成为评估振动试验效果的关键参数,为了能精确获取环境振动试验中的加速度值,特别是在使用集成电路式压电传感器(IEPE加速度传感器)时,本文提出了一种针对IEPE加速度传感器的高精度测量电路设计方案。该电路方案旨在解决IEPE加速度传感器在振动试验中信号提前与处理的问题,电路主要包括传感器的恒流供电、信号调理、信号输出、电源管理和噪声抑制等模块。该电路成功实现了对IEPE加速度传感器的精确测量,并应用与环境振动试验箱中,为振动试验、工业监测、机械健康诊断等领域提供了可靠的测量手段。

三角剪切型压电加速度传感器固有频率计算及优化

针对应用于高温环境的剪切型压电加速度传感器,建立了固有频率的计算模型,研究了刚度和几何结构参数对加速度传感器固有频率的影响。研究结果表明:该模型计算结果和有限元仿真结果基本一致。三角支柱的法向刚度对传感器整体刚度的影响最大。中心支柱的几何尺寸对固有频率影响最大,质量块的长宽以及压电片高度对固有频率也有较大影响。优化后的传感器实物样品,固有频率较优化前实现了约20%的提升,符合理论变化趋势。该计算模型和计算结果有助于优化三角剪切型压电加速度传感器。

用于矢量水听器的压电单晶面剪切模式加速度计设计

面剪切振动模式产生于[011]极化方向zxt-45°切型的压电单晶,因具有高压电系数、高机械品质因数、高柔顺系数和低串扰效应等优点,故面剪切模式成为小尺寸、高灵敏度压电传感器的理想选择,在矢量水听器中有着良好的应用前景。该文通过分析面剪切模式振动原理,推导了面剪切模式压电加速度计的电压灵敏度表达式。利用有限元分析软件构建面剪切加速度计模型,研究结构参数对面剪切压电加速度计电压灵敏度和谐振频率的影响规律,优化结构尺寸,最终仿真得到面剪切加速度计开路电压灵敏度为389.72 mV/g,工作频带为20 Hz~3 kHz,横向灵敏度小于3.45%。研究结果表明,与传统的剪切式加速度计相比,所设计的面剪切式加速度计在质量块质量降低50%的同时,电压灵敏度提高了11.6%,这为降低水听器的平均密度、提升水声探测性能提供了新思路。

互易压电加速度计校准技术研究

介绍一种针对内部带有驱动部件的压电加速度计的校准方法,基于互易法的校准原理,通过2次试验测量2个端口灵敏度的比值和乘积,实现互易压电加速度计的校准。通过建立互易压电加速度计的振动方程及力学模型,分析了灵敏度比值、灵敏度乘积和自校准系数的频率响应特性,并说明了对应的校准方法。与激光干涉法进行了对比验证实验,实验结果表明:在频率范围5~4000 Hz,2个端口灵敏度的平均相对偏差分别不超过1%和2%,最大相对偏差分别不超过2%和4%。

高温压电加速度传感器设计与仿真优化

高温压电加速度传感器被广泛应用于振动与冲击测试、故障诊断与监测方面。针对传统压电加速度传感器灵敏度温度漂移过大的问题,该文设计了一种高温压电加速度传感器,该加速度传感器采用正负温度系数的压电元件堆叠设计,以抵消温度变化的影响,进而降低温度漂移。5层YCOB压电元件和1层GdCOB压电元件堆叠构成压缩型压电加速度传感器。应用ANSYS对传感器的性能进行仿真优化,并对提出的降低灵敏度温度漂移的方法有效性进行了仿真验证。结果表明,在常温~800℃全温度范围内,该传感器的灵敏度温度漂移小于±3%,其具有高温稳定性好、测量精度高的优点。

压电式加速度传感器在振动测量系统的应用研究

压电式加速度计具有体积小、质量轻、测量范围宽等特点,在振动测量系统中得到广泛应用。分析了压电式传感器作为一种机电换能器,将振动加速度转变成为电量进行测振的具体原理;阐述了基于压电式加速度计构建振动测量系统的总体方案,整个测试系统主要由压电式加速度计、电荷放大器、动态信号分析仪组成,采集所得振动信号可以实时显示、存储、分析和处理。最后,将该系统应用于压路机实际测振进行了验证。

压电加速度计本底噪声研究

针对压电加速度计的本底噪声,以压电变换器和电荷放大器为研究对象,建立压电变换器单自由度弹簧-质量-阻尼机械谐振系统力学模型和压电元件的电学模型,以结型场效应管(JFET)为核心元件,研究电路中的主要噪声源,建立各自的噪声模型。利用En-In噪声模型构建方法将电路内部噪声源等效到输入端,同时将Y-Δ变换原理引入T型偏置网络的噪声分析中。利用噪声模型推导出压电加速度计噪声谱密度表达式,将获得的实验数据与利用表达式得到的理论计算值进行对比,验证表达式的有效性与正确性。通过此表达式分析影响加速度计噪声的关键因素,总结出加速度计低噪声设计原则,为提高加速度计的信噪比提供理论基础。

压电加速度传感器冲击测量中低频失真的理论分析与实验验证

冲击谱是一连续谱,其频谱范围从零到无穷大。由于压电加速度传感器的频率范围有限,在冲击测量中不可避免地会产生频率失真,频率失真包含低频失真和高频失真。压电加速度传感器在冲击测量中的低频失真主要表现为基线不回零。分别从矩形冲击波、锯齿形冲击波和半正弦冲击波引起的传感器响应入手,定量分析了压电加速度传感器冲击测量基线不回零的问题,最后利用落体冲击试验台对理论分析进行了实验验证。

压电式加速度计在工程测振中的应用分析

介绍了压电式加速度计的特点及其在振动测量中的应用;分析了压电式加速度计的测振原理、结构型式、技术指标;提出具体工程测振中,传感器选用原则和使用过程中应采取的有效措施及注意事项;最后,结合实际工程进行了压电式加速度计的选择,并应用于压路机振动轮加速度的测振系统中,进行了实证。

压电加速度测量系统的设计

现代工业和自动化生产过程中,动态测试中振动和冲击的精确测量很重要。常用压电加速度传感器来获取冲击和振动信号。在研究压电加速度传感器的基础上,分析了测量的工作原理,提出加速度测量的设计方法;加入温敏元件,进行温度补偿,使其应用温度范围扩大。给出适合该类传感器的信号检测电路和加速度测量系统组成。此设计方法具有较高的准确性和应用推广价值,并具有结构简单,成本低,性能稳定等优点。

一种新型压电加速度传感器研究

针对大长径比弹丸高速侵彻中刚体过载信号与高频振动信号混叠带来目标难以识别的问题,研究一种具有开关特性的压电加速度传感器;建立了该传感器的力学模型并对其特性进行了研究.利用相对比较法对新型加速度传感器及普通加速度传感器进行了冲击试验.实验测试结果表明,所设计的压电加速度传感器可衰减高频振动信号,有利于侵彻过程中目标信息的获取与识别.

压电式加速度传感器的频响检测分析

频响特性是传感器的重要指标,频响分析是一种得到广泛应用的系统分析方法。介绍了一种频率响应检测技术的实现方法,论述了振动信号采集、分析程序的实现,检测的硬件系统主要为多通道高速采集卡、信号发生调理装置。利用该检测系统对不同厂家、型号的压电式加速度传感器进行检测实验,实验结果表明此系统可以完成对压电式加速度传感器的频响检测分析。

柔性自适应桁架及其振动最优控制实验

基于dSPACE系统和所研制的锆钛酸铅(PZT)压电作动器,建立了第一阶频率低达5Hz的三棱柱自适应桁架实验平台,通过有限元建模和实验参数修正,利用异位加速度反馈信号进行了线性二次型Gauss(LQG)最优反馈控制实验和仿真.结果表明:对比无控状态,采用最优控制只需很小控制电压,可使桁架在低阶典型频率激励下的振幅降低90 %以上;而当桁架受扰动后,振动衰减时间减少超过80 % ;验证了实验平台配置的合理性和所研制的PZT压电作动器、控制模型的有效性;控制数值仿真与实验在加控前后振幅抑制程度相同,控制仿真与实验中振幅衰减过程的差别通过激振过程仿真与实验的对比得到了阐明.