Wind speed and direction measurement based on arc ultrasonic sensor array signal processing algorithm

This article investigates a kind of method to measure the wind speed and the wind direction, which is based on arc ultrasonic sensor array and combined with array signal processing algorithm. In the proposed method, a new arc ultrasonic array structure is introduced and the array manifold is derived firstly. On this basis, the measurement of the wind speed and the wind direction is analyzed and discussed by means of the basic idea of the classic MUSIC (Multiple Signal Classification) algorithm, which achieves the measurements of the 360° wind direction with resolution of 1° and 0–60 m/s wind speed with resolution of 0.1 m/s. The implementation of the proposed method is elaborated through the theoretical derivation and corresponding discussion. Besides, the simulation experiments are presented to show the feasibility of the proposed method. The theoretical analysis and simulation results indicate that the proposed method has superiority on anti-noise performance and improves the wind measurement accuracy.     

基于双阵元超声波接收阵列的风矢量测量

针对当前超声波测风仪测量精度不高及抑制噪声干扰能力不强的问题,提出了一种双阵元超声波接收阵列结构及基于该结构的风矢量测量方法.首先,设计了一种基于超声波测风原理的风速风向测量系统结构,该结构中包含一个超声波发射阵元和两个超声波接收阵元;然后,依据该系统结构给出了一种基于相关方法的超声波时延估计算法,根据超声波传输时间与...     

超声波换能器测风阵列的优化设计

为了减弱风场在超声波换能器测风阵列中产生湍流,降低湍流对信号采集精度的影响,分析了换能器阵列影响流场的因素,采用6个收发一体的超声波换能器,设置独立的3条测风路径,根据不同来流方向,建立了风速计算模型,结合换能器晶片的工作特性,改进测风阵列的设计,降低了阴影效应的影响。利用FLUENT软件,通过设置不同的雷诺数、来流风速和风向参数,仿真了流场在阵列中分布特性,得到阵列速度云图和测风路径速度变化图,验证了改进后的测风阵列性能有效提升,说明了所设计阵列能满足测风精度提高的要求。     

基于高阶累积量的阵列式超声波传感器风速风向测量

针对现有超声波测风系统在实际应用中环境噪声抑制效果差、风速和风向测量精度不高的问题,提出了一种基于高阶累积量的阵列式超声波传感器风速风向测量方法。所提方法采用一种由一个超声波发射阵元和五个超声波接收阵元组成的阵列式超声波测风系统结构,并在此系统结构上,采用基于高阶累积量的多重信号分类(MUSIC)算法,抑制高斯白噪声及高斯色噪声的干扰,实现高斯混合噪声下风速风向的有效测量。所提方法与应用相关算法的测风方法相比,具有更高的噪声抑制能力及更高的风速风向测量精度。最后通过仿真实验与实测数据验证实验对所提方法的有效性进行了验证与分析,实验结果表明风速和风向角的测量误差分别为2.3%和-2°,基本达到了超声波测风方法的技术要求。     

基于二次相关的超声波风速风向测量方法

为解决超声波测风仪存在的抑制噪声能力不足、受环境温湿度等影响导致稳定性差等问题,提出一种基于二次相关算法的三阵元超声波测风方法。首先结合超声波测风原理设计了一种三阵元测风结构,该结构包含3个收发一体式超声波换能器;其次依据该系统结构给出一种基于二次相关的超声波传播时间测量方法,利用二次相关算法对噪声抑制更强的性能可有效提高风速风向测量的精度,并从理论上说明了所提测风方法不受超声波本身传播速度即环境温湿度对其的影响。最后通过模拟仿真实验和搭建的实际测量系统对所提方法进行了有效性验证。在实际测量中风速风向角的最大测量误差分别为2.0%和2.1°,基本达到了超声波风速风向测量的精度要求。     

应用微分算法处理特种管道测厚激光超声信号

为了实现特种管道在高温、高压、辐射等特殊环境下管壁厚度的非均匀性检测,提出一种基于微分算法的管道壁厚激光超声测量及特征信号处理方法。采用脉冲激光激励和激光干涉探测的激光超声方法,实验测得管道试件的宽频带激光超声信号。采用数字平均算法对宽带激光超声信号进行去噪处理,提高原始激光超声信号的信噪比。采用微分算法对激光超声信号进行特征提取处理,得到表征管壁厚度的激光超声特征信号。根据管道材料声速和激光超声传播时间反演计算得到管道试件的壁厚值,管壁厚度测量值与实际值的误差小于5%。研究表明,基于微分算法的管道壁厚激光超声测量及特征信号处理方法具有良好的信噪比、准确的信号特征量和较高的测量精度,可用于管道壁厚的在线实时检测以及因腐蚀、应力引起的管道壁厚不均匀性检测。     

高精度超声风速测量系统设计与实现

时差法是超声风速风向测量系统的基本方法.文中首先对影响时差法测量精度的因素进行分析,针对这些影响因素,在超声换能器设计、阵型设计、电路系统设计和信号处理算法等方面提出了提高系统精度的设计方案,并制成样机.实验测试表明,文中所实现的系统已经基本达到国际尖端产品的测量精度,且具有体积小、可靠性高等优点,具有很高的实际应用价值.     

基于时差法的高精度超声波风速风向测量系统

针对风速风向对悬索桥的安全性影响,为了实现对悬索桥风速风向的精确监测,设计了基于时差法的高精度超声波风速风向测量系统.系统采用STM32为控制单元,超声波换能器为敏感单元,实现发送和接收超声波信号,MS1022高精度时间测量模块为测试单元,实现超声波飞行时间的计量,LoRa无线模块为数据传输单元,实现风速风向数据上传至...     

Applications of digital signal processing methods in TOF calculation of ultrasonic gas flowmeter

Ultrasonic gas flowmeters (UGFM) are extensively used in petroleum, chemical, natural gas and other fields because of their distinctive measurement advantages. As the core technology of the UGFM, digital signal processing technology determines its measurement accuracy and stability. This paper systematically reviews the signal processing methods for measuring the TOF (time of flight) based on the principle of time difference method. According to the stability of the feature information extracted by different digital signal processing methods, the advantages and disadvantages of each method are analyzed. Aiming at the problems of serious energy attenuation, weak echo signal amplitude, and low signal-to-noise ratio (SNR) when ultrasonic signal propagate in the gas, different signal processing methods are evaluated and compared from the aspects of calculation accuracy, response speed, anti-interference ability and sensitivity to parameter changes. Finally, some improvement ideas and directions for further research are proposed according to the analysis results.     

基于能量变化率的气体超声波流量计信号处理方法

针对气体超声流量计信号处理中不易找到稳定的测量特征点的问题,提出了一种基于能量变化率的过零检测信号处理方法,以及最优阈值参数的选取方法。基于能量变化率的过零检测信号处理方法首先求取能量变化率曲线上的关键阈值点,然后回溯到原始波形信号上,找到对应的过零点,并以此作为信号的稳定特征点,进而求得信号的传播时间及气体流量。在以FPGA和DSP为核心的气体超声流量计信号处理系统上实时实现了算法,并进行标定实验,实验结果验证了方法的有效性。     

Application of ultrasonic Doppler velocimetry to molten glass by using broadband phase difference method

An ultrasonic velocity profile (UVP) measurement in high temperature molten glass was presented using buffer rod technique. A ceramic buffer rod was used to transmit ultrasound into molten glass. The rod had a taper shape and porous cladding to suppress trailing echo, which is the spurious echo in the buffer rod measurement. The broadband signal processing method was presented to improve noise tolerance in velocity estimation. This method is based on the phase difference method, which is originally proposed as a narrowband method. Measurable distance of the UVP measurement was investigated combining the buffer rod and the broadband signal processing method. Experiment was conducted at the temperature from 1000 °C to 1200 °C. As a preliminary test, motion tracking in molten glass was successfully demonstrated.     

A novel method for digital ultrasonic time-of-flight measurement

Most ultrasonic ranging measurements are based on the determination of the ultrasonic time-of-flight (TOF). This paper develops a novel method for the TOF measurement which combines both the improved self-interference driving technique and the optional optimization signal processing algorithms. By stimulating the transmitter with the amplitude modulation and the phase modulation envelope square waveforms (APESWs), the proposed system can effectively reduce the errors caused by inertia delay and amplitude attenuation. In addition, based on different signal-to-noise ratio test conditions, the resultant received zero-crossing samples, which are deteriorated by noise, can be precisely inspected and calculated with two optimized algorithms named zero-crossing tracking (ZCT) and time-shifted superposition (TSS) method. The architecture of the designed system is divided into two parts. The novel APESW driving module, the received envelope zero-crossings phase detection module, and the ZCT method processing module are designed in a complex programmable logic device. The TSS signal processing module and the optimization algorithm discrimination program module are integrated in a digital signal processor. The TOF measurements calibrated in ultrasonic ranging experiments indicate that the relative errors of the method are limited in ±0.8%. Therefore, a feasible method is provided with the advantages of high noise immunity, accuracy, low cost, and ease of implementation.     

超声波传输时间精密测量方法及应用研究

根据超声波回波信号是一个变幅周期性信号这一特点,提出一种用数字细分来精密测量超声波传输时间的方法,阐明了超声波换能器驱动电路原理及利用FPGA电路和高分辨率A/D电路通过高频采样来实现这一方法的原理,并采用该方法和电路设计了超声波流量计。指出超声波传输时间测量的分辨率取决于超声波信号的频率和A/D电路的分辨率,为保证测量精度,应尽可能采用较高的采样频率。超声波传输时间的测量综合了全部回波信号采样数据,有很好的可靠性和很强的抗干扰能力。     

Design and application of a small size SAFT imaging system for concrete structure

A method of ultrasonic imaging detection is presented for quick non-destructive testing (NDT) of concrete structures using synthesized aperture focusing technology (SAFT). A low cost ultrasonic sensor array consisting of 12 market available low frequency ultrasonic transducers is designed and manufactured. A channel compensation method is proposed to improve the consistency of different transducers. The controlling devices for array scan as well as the virtual instrument for SAFT imaging are designed. In the coarse scan mode with the scan step of 50 mm, the system can quickly give an image display of a cross section of 600 mm (L) × 300 mm (D) by one measurement. In the refined scan model, the system can reduce the scan step and give an image display of the same cross section by moving the sensor array several times. Experiments on staircase specimen, concrete slab with embedded target, and building floor with underground pipe line all verify the efficiency of the proposed method.     

基于波原子理论的超声检测信号降噪方法

如何在消除噪声的同时更好保留信号中的有效信息一直是无损检测信号处理研究中的热点。尝试通过构建虚拟观测信号将单通道超声检测信号扩展为信号阵列,利用波原子方法进行降噪处理,并引入非局部均值算法进行平滑以压制波原子硬阈值滤波方式可能产生的伪吉布斯现象。用该算法对仿真信号与某碳酸钙污垢层超声检测信号进行降噪,并与小波阈值降噪进行对比。结果显示该方法对信号信噪比的提高、信号有效特征及微弱信号的保持均有较好效果。     

一种复杂结构件圆柱面扩散焊缝阵列超声检测方法

航空发动机某高温合金盘构件采用盘体与叶片环进行焊接的方式制备,由于构件结构复杂,在检测圆柱形焊接面缺陷时,采用单晶超声检测换能器检测效率不高,缺陷信号信噪比低。为提高该种结构件的检测能力,研究圆柱面焊缝的阵列超声自动检测方法,分析面积型缺陷和声源的相对位置对缺陷反射声压和波型转换的影响,提出一种基于双阵列换能器的一发一收检测方案。根据高温合金盘结构设计基于双阵列换能器的声束发射-接收方法和圆柱面焊缝全覆盖检测方案;基于时域有限差分方法建立高温合金盘的阵列超声声学响应仿真模型,对检测参数进行设计和优化。对含有人工缺陷的实际试样进行检测试验,结果表明所提出的双阵列超声换能器检测方法能有效检测到圆柱面焊缝区域? 2 mm的当量缺陷。     

Design of transit-time difference ultrasonic heat meter based on TDC-GP21

According to the transit-time difference measurement method,we proposed a design scheme of ultrasonic heat meter based on TDC-GP21.The measurement unit TDC-GP21 mainly completes transit-time measurement and inlet,outlet temperature measurement functions.Control unit and data processing unit based on MSP430F4152 of TI corporation complete functions including peripherals control,data analysis,temperature compensation algorithm,flow pattern compensation algorithm and low power consumption control.The design meets the Town Construction Professional Standard CJ 128-2007,and furthermore,some performances can be improved.     

A New ultrasonic signal processing scheme for detecting echoes of different spectral characteristics in concrete using empirical mode decomposition

In this work, a new signal processing scheme is proposed to improve ultrasonic echoes detection in concrete, a construction material and inhomogeneous propagation medium, in which the backscattering and the grain noise mask the useful signals. Firstly, the time-domain ultrasonic signal is measured. Then the original signal is separated into Intrinsic Mode Functions (IMF) using Empirical Mode Decomposition. Secondly, the Fourier analysis is performed on each IMF. Examining the behaviors of the IMFs in the time and frequency domain, one can judge which IMF represents noise, echoes wave. Then we use nonlinear processing techniques to recombine the selected IMFs. Experimental results are presented and analyzed on a trapezoidal concrete/mortar/cement-paste prism specimen, showing that the proposed technique has an excellent performance. The improvement in defect detection was experimentally verified too on a prism based specimen of mortar with artificial defect.     

变风速条件下风力机轴承故障特征提取

针对风速变化条件下风力发电机轴承故障特征的检测问题,提出了一种基于灰狼优化( GWO )和双稳态杜芬振荡器的随机共振( SR )的故障特征提取方法.首先,根据风速估计故障特征信号的频率,通过合适的采样频率采集风力发电机的振动信号并对采集的信号做归一化处理.随后,根据风速尺度引入变换系数对频率 时间尺度进行变换.此外,利用灰狼算法方法将杜芬振子的阻尼比和系统参数调整到最优值.最后,通过杜芬系统和尺度恢复获得可识别信号.结果表明,所提出的方法能提取原始信号中的故障特征信号.     

Acoustic CT system for temperature distribution measurement

In this paper,a measurement method for crosssectional temperature distribution is addressed. A novel method based on an acoustic CT technique is proposed. Specifically,the temperature distributions are estimated using the time of flight data of several ultrasonic propagation paths. The times of the flight data contain both temperature and wind effect,and the method to select only temperature component is introduced. A filtered back projection method is applied to reconstruct the temperature distributions from the time of flight data. An experimental system was designed and fabricated to realize simultaneous temperature and wind velocity distribution measurements. Through this system,the effectiveness of the proposed measurement method is confirmed.