应用于定位的光纤振动传感技术的发展现状

利用光纤作为传感器提取沿途振动信号,通过对检测信号的处理和分析,可有效地检测和定位发生的故障或入侵行为等。分布式光纤振动传感器利用光波在光纤中传输时相位、偏振等对振动的敏感特性,连续实时地监测光纤附近的振动,并能够定位预防事故,有较好的应用前景。根据传感原理,分布式光纤振动传感技术可分为基于干涉原理和基于后向散射探测技术两类。该文主要从以上两个方面综述分布式振动传感器的主要技术和发展动态。     

Note: anti-strong-disturbance signal processing method of vortex flowmeter with two sensors

Some digital signal processing methods have been used to deal with the output signal of vortex flowmeter for extracting the flow rate frequency from the noisy output of vortex flow rate sensor and achieving the measurement of small flow rate. In applications, however, the power of noise is larger than that of flow rate sometimes. These strong disturbances are caused by pipe vibration mostly. Under this condition the previous digital signal processing methods will be unavailable. Therefore, an anti-strong-disturbance solution is studied for the vortex flowmeter with two sensors in this Note. In this solution, two piezoelectric sensors are installed in the vortex probe. One is called the flow rate sensor for measuring both the flow rate and vibration noise, and the other is called the vibration sensor for detecting the vibration noise and sensing the flow rate signal weakly at the same time. An anti-strong-disturbance signal processing method combining the frequency-domain substation algorithm with the frequency-variance calculation algorithm is proposed to identify the flow rate frequency. When the peak number of amplitude spectrum of the flow rate sensor is different from that of the vibration sensor, the frequency-domain subtraction algorithm will be adopted; when the peak number of amplitude spectrum of the flow rate sensor is the same as that of the vibration sensor, the frequency-variance calculation algorithm will be employed. The whole algorithm is implemented in real time by an ultralow power micro control unit (MCU) to meet requirements of process instrumentation. The experimental results show that this method can obtain the flow rate frequency correctly even if the power of the pipe vibration noise is larger than that of the vortex flow rate signal.     

空间集成光纤应变传感器在轻便材料结构振荡监控上的应用

空间集成传感器比起离散定位传感器更适合于最优控制体系。报道了将此概念应用到振荡传感的情况。柬流动力学被应用到集成传感器的设计上，其主要目的是显著地消除或减小高次模的信号幅度。这一设计可以用到没有使用外部信号处理技术，特别是经常应用于工程的钳位-钳位束的振荡传感。     

An efficient algorithm for processing data from a multi-point sensor of vibrations

A new technique of vibration sensing, based on a polarimetric fibre-optic strain sensor, is presented; it is designed for localisation of multiple sources of disturbances in a broad frequency spectrum without using fibre gratings. A mathematical model of the sensor is used for development of a variational method for estimation of amplitudes of component vibrations on the basis of noisy samples of the signal at the output of the sensor. This method is implemented in a new algorithm of estimation, being 100–1000 more efficient (in terms of computing time) than an algorithm published previously.     

盾构实验台盘形滚刀垂向振动间接测试研究

为解决盘形滚刀垂向振动测试难的问题,笔者设计了滚刀回转切削振动测试系统,提出一种盾构实验台间接测试盘形滚刀垂向振动位移的方法,即用ZA-21电涡流位移传感器来测量滚刀顶部振动量的方法以间接测定滚刀破岩面的振动量。然后在机械振动综合实验平台上用加速度传感器进行实测,采用Matlab中的cor-rcoef函数对采集的时域信号计算相关性,计算结果与实测曲线表明,测量滚刀顶部振动量与直接测量滚刀破岩面振动量有很高的相关性,由此证明测试方案的可行性。     

无线传感网络定位中利用游标效应的高精度RF传播时间测量方法(英文)

无线传感网络中传感器节点的定位信息很重要,而精确的测距技术是获得传感器节点间可靠的距离信息所不可或缺的。在时钟系统中引入游标卡尺的原理,提出了高精度的RF飞行时间测量方法。2个异步时钟好像游标卡尺的主尺和副尺刻度一样,可以引出新的比原时钟频率高很多的虚拟时间分辨率。用2种异步时钟连续进行RF发射和接收,产生与RF信号传播时间有关的测量模式,由测量模式推测出RF传播时间。开发了短距离RF收发的实验系统,实验证明8 MHz的低分辨时钟系统可以测出12.5 ns的高分辨RF传播时间。     

编码式谐振SAW无源无线温度传感阵列系统

提出了一种新型编码式谐振声表面波无源无线温度传感系统。该传感系统采用间歇正弦脉冲串信号作为无线激励信号，而经谐振式声表面波器件延迟后的反射波是一瞬时变化的振荡波形，该反射信号的频率与声表面波器件固有频率相关。温度改变，其反射信号的频率也发生变化。该传感阵列系统利用不同延迟线构成编码器，可实现大规模的传感器构造。该方法不仅有谐振式无源无线传感器距离远的优点，而且，还具有延迟型大规模编码的优点。该法还可用于无源无线的目标识别。     

Small diameter fiber Bragg gratings and applications

Small diameter optical fibers are preferred in sensing systems as they have less influence on mechanical performance of smart composite. The static and dynamic monitoring capabilities of the small-diameter fiber Bragg gratings (FBG) are experimentally studied in this paper. Firstly, a small-diameter FBG is used as a strain sensor. Secondly, a temperature sensor is fabricated using a specific FBG. Thirdly, a simple sensing system is proposed in order to discriminate temperature at sensing point. Finally, utilization of these small diameter FBGs for vibration monitoring is discussed. The experiments revealed that the central wavelengths of the small-diameter fiber Bragg gratings shift linearly with strain or temperature. The FBG is more sensitive than a thermocouple inside the thermostat. Acquisition and analysis of the dynamic signal indicates that the designed FBG can be used for dynamic signal monitoring.     

基于耦合源误差分析的转子振动信号识别方法

转子振动信号实时监测是保障旋转机械健康运行的关键,转子圆度误差和电涡流位移传感器误差的耦合源误差在以往的研究和振动监测中很少考虑,使得转子振动信号有一定的失真,甚至会引起误判。以实际转子为例,提出了圆度误差测量表达式;测量和分析了两种常用电涡流位移传感器的误差,利用傅里叶拟合方法构建了圆度误差和电涡流位移传感器耦合源误差表达式,建立了耦合源误差与转子振动信号之间的映射关系。提出了点-点法、平均值法与最大值法3种转子振动信号识别方法,3种方法都能有效识别转子振动信号,其中点-点法最精确,识别误差占比约20%;平均值法计算简便,识别误差占比约10%;最大值法偏保守,但可有效避免误判,识别误差占比约32%。     

基于分布式光纤振动传感原理的电力电缆故障定位技术研究

研究一种基于分布式光纤振动传感原理和电缆局部放电原理的电力电缆故障定位技术.通过在电缆上施加高压脉冲,使得电缆上有故障的位置产生局部放电,从而产生振动信号.并将放电脉冲信号同步传输给分布式光纤振动监测系统.通过分布式光纤振动传感技术来探测电缆沿线放电产生的振动信号,并对振动信号进行定位.将该故障定位技术应用于电力电缆沿线上监测电缆故障的状态分布,并进行试验验证.实验结果表明,该系统可实现监测多回路30 km电缆线路的故障分布状况,并对故障点进行准确定位.     

Monitoring of Ball Bearing Operation under Grease Lubrication Using a New Compound Diagnostic System Detecting Vibration and Acoustic Emission

Our new compound diagnostic system comprised of a compound sensor, a signal processor, and a personal computer installed signal processing software. The compound sensor made by an advanced sensor fusion technique was able to detect simultaneously the vibration acceleration and the acoustic emission by itself. The signal processor received a signal from the sensor and separated it into the vibration acceleration signal and the acoustic emission signal. The signal processor and the personal computer processed the acceleration signal and acoustic emission signal for diagnostic information. The rolling contact fatigue process of a ball bearing under grease lubrication was monitored using the compound system. The system outputs diagnostic information, for example, the means, the variance, the skewness, and the kurtosis of the vibration acceleration signal and the acoustic emission signal. In diagnosing the rolling contact fatigue failure, the root mean square (rms) value of the vibration acceleration was most effective, and the mean of the demodulated acoustic emission was second to the rms value of the acceleration in effectiveness. From the result of the evaluation, it became clear that the system was useful for diagnosing rolling contact bearings under grease lubrication.     

磁致伸缩与磁弹一体化传感器的研制

为开发具有缺陷检测与应力测量双功能的单体传感器,设计出一种包括静态偏置磁路和内、外层感应线圈的一体化传感器结构,可工作于磁致伸缩与磁弹传感器两种模式。结合磁致伸缩与磁弹基本理论,以能量转换效率和应力测量灵敏度为指标,采用有限元仿真法对一体化传感器的偏置磁场进行优化选取。一体化传感器的试验测试结果表明,传感器工作于磁致伸缩传感器模式时,可在直径6.3 mm钢杆中激励产生L(0,1)模态超声导波并有效检测出宽度和深度均为1 mm的槽型缺陷,增加外层感应线圈的驱动直流可对静态偏置磁场强度进行补偿以使接收的缺陷回波信号幅值增加,提高传感器的缺陷检测能力;工作于磁弹传感器模式时,随激励信号幅值增大,传感器的应力测量灵敏度和测量结果线性度均有提高,其中测量结果线性拟合确定系数最高达0.992 4,表明一体化传感器可用于高精度应力测量。     

基于声表面波谐振器和延迟线的编码型无源无线阵列传感器

提出了一种新型延迟编码式谐振声表面波无源无线传感系统。该传感单元由单端口谐振器和延迟线组成，激励信号采用间歇正弦脉冲串信号。响应为一变化的振荡波形，该信号的频率与声表面波器件固有频率相等。该传感阵列系统利用不同延迟线构成编码器不仅有谐振式无源无线传感器距离远的优点，而且，还具有延迟型大规模编码的优势。该方法提高了传感系统遥感测量的距离、灵敏度和信噪化，也为该声表面波阵列传感器的广泛应用提供了保证。     

Sensitivity of transverse shift inside a double-grating Talbot interferometer

We study the Talbot interferometry with an additional mask grating located behind the diffraction grating. The self-imaging so-called, Talbot carpet, can be very sensitive to an external perturbation. We here show the measurement and the optimization of sensitivity of transverse shift of one of the two gratings inside Talbot interferometer as a function of grating constant and opening fraction of the grating itself. The results show that the sensitivity of the transverse shift is increased dramatically at smaller grating constants while no effect for different opening fractions. A sensor of our simple scheme can be suggested as an excellent inertial sensing applications such as displacement sensor, spectrometer, and vibration sensor.     

基于载波调制的光纤振动传感复用系统

提出了一种基于载波调制的光纤振动传感复用系统,其优点在于,对于感应外界扰动的不同感应光纤单元产生的干涉信号用不同频率的载波进行调制,相邻载波频率之间的频率差无需大于外界扰动引起的信号基波频率上限的两倍。各光纤感应单元形成的信号被共同的光电探测器检测后,利用信号基波来分析扰动信号的物理量,利用载波基波或谐波的边带判断感应扰动信号的光纤。     

Note: Self-sensing based on charge control improves the performance of active damping using piezoelements

A piezoelectric element can be used separately as a sensor or an actuator. A self-sensing strategy based on a charge driver can utilize a piezoelectric element as a sensor while actuating. The strategy was proven via experiments on a cantilever vibrator using a piezoelectric plate with both sensing and actuating functions. The amplitude of the vibration was actively damped by a factor exceeding 90%. The method can be used in numerous fields, including scanning probe microscopy, vibration suppression, and monitoring the health of structures.     

心音信号的检测与处理

目的:实现低负荷心冲击信号提取,方法:使用固体振动传感器提取心音信号,使用双向检波及低通滤波实现心音包络的提取,结果:与心电信号的同步对照显示该方法能够有效提取心冲击信号,结论:基于固体振动传感器的心音检测的技术能够有效提取心冲击信号,是低负荷心冲击信号提取的有效途径。     

基于ZigBee的无线振动检测系统设计

针对机械设备的振动信号检测问题,采用ZigBee技术设计了一套无线传感器网络振动检测系统,详细介绍了系统结构,硬、软件设计方案和通信方法。基于Zig Bee技术并结合MEMS传感器开发的无线传感器系统,能够实现无线检测运行机械设备的三轴振动信号,利用Qt框架设计的上位机软件系统可以实现三轴振动信号的波形显示、数据存储以及利用快速傅里叶变换获得的频谱图检测设备的运行状况。实验表明,通过该系统可实时无线检测现场机械设备的振动信号,提高了机械设备故障诊断的自动化水平。     

心音信号的检测与处理

目的：实现低负荷心冲击信号提取,方法：使用固体振动传感器提取心音信号,使用双向检波及低通滤波实现心音包络的提取,结果：与心电信号的同步对照显示该方法能够有效提取心冲击信号,结论：基于固体振动传感器的心音检测的技术能够有效提取心冲击信号,是低负荷心冲击信号提取的有效途径。     

光纤光栅传感器阵列在撞击定位监测中的应用

本文提出基于半导体环形激光器的光纤传感阵列系统,用于在铝板上撞击定位监测。采用光纤法布里-珀罗(F-P)标准具对光纤布拉格光栅(FBG)传感器信号进行解调。施加在FBG传感器的应变被编码为FBG反射光的波长位移,然后由自由光谱范围为50 GHz的光纤F-P标准具转换为强度调制。通过波分复用技术,光纤F-P标准具可同时解调多个FBG信号,光纤传感阵列系统安装在厚度为1 mm的铝板上,50 g的小钢球在20 cm的高度自由下落撞击铝板产生声发射信号。利用时频小波分析,从测量的FBG传感器瞬态响应中获得的Lamb波的群速度频散曲线,并根据三角定位算法,确定撞击点的坐标。经过撞击试验,通过本系统和定位算法的平均定位精度误差在30.89 mm,达到了较好的精度。