非接触应变测量的数字散斑相关方法的研究

针对传统接触式应变测量的局限性,探讨了基于数字图像处理技术的非接触式应变测量方法--数字散斑相关方法(Digital Speckles Correlation Method,DSCM),并用单向拉伸实验对该方法进行了验证,结果表明,该方法是一种实用快速、高精度的变形测量方法.     

Non-destructive evaluation of semiconductor package by electronic speckle pattern interferometry

This paper proposes non-destructive ESPI technique to evaluate inside defects of semiconductor package quantitatively Inspection system consists of ESPI system, thermal loading system and adiabatic chamber The technique has high feasibility in non-destructive testing of semiconductor and gives solutions to the drawbacks in previous technique, time-consuming and the difficulty of quantitative evaluation In result, most of defects are classified in delamination, from which it is inferred to the insufficiency of adhesive strength between layers and nonhomogeneous heat spread The 90% of tested samples have a delamination defect started at the around of the chip which may be related to heat spread design     

Displacement measurement using digital speckle multi-frequency harmonic wave correlation method

In the displacement measurement using digital speckle correlation method, significant measuring error due to the multi-peak nature of the correlation coefficient function is a critical issue as sometimes the secondary peak can be wrongly determined as the maximum instead of the highest peak. In the multi-frequency harmonic wave correlation method (MHCM) as proposed in this work, for speckle patterns before and after the displacement, correlation calculations were performed on corresponding sets of data matrices assembled by amplitudes/intensities obtained from harmonic waves with different frequencies. The calculated maximum correlation coefficients were compared with each other to locate the maximum in order to measure the displacement. Both ultrasonic speckle MHCM and laser speckle MHCM were applied to the displacement measurement respectively. Measured results indicated that MHCM effectively helps to ensure the correct determination of the maximum correlation coefficient, to avoid random errors caused by other factors and improves the measurement accuracy in the meanwhile.     

Roughness form and waviness measurement by means of light-scattering

This paper deals with a non-contact, optical measuring method which unites the assessment of roughness form and waviness in one single instrument. The     

Automatic compensation for grinding wheel wear by pressure based in-process measurement in wet grinding

This paper deals with an application to automatic compensation of grinding wheel wear by a pressure based in-process measurement method in wet grinding. A pressure sensor is set beside a grinding wheel with a small gap. When grinding fluid is dragged into the gap by the rotation, hydrodynamic pressure, which corresponds to the gap length and the topography, can be measured. No electromagnetic properties of the workpiece and grinding wheel affect measured results. This method is applied to a CNC surface grinding machine. The pressure distribution and the relationship between the pressure and the gap length are measured. The pressure is decreased with the increase of the gap length. Its dispersion is around 1% for 0.5 μm-wear of a grinding wheel with 250 μm grit size. The dimensional error of a workpiece using the feedback of the wear is less than the feeding step, for the compensation, of 1 μm.     

Simultaneous in-plane and out-of-plane deformation measurement by speckle multi-recording method

An in-plane and out-of-plane deformation simultaneous measurement method using only two speckle patterns grabbed before and after deformation of an object with rough surfaces using two cameras has been proposed. However, there are some problems concerning the setup of optical system, the aspect ratio of grabbed image data and so on in the conventional method. To solve these problems, the new optical system is proposed by using the multi-recording technology. Though multi-recording technologies have been already employed conveniently in the off-axis digital holography, the technologies have not been used functionally enough in speckle interferometry. In this paper, an in-plane and out-of-plane deformation simultaneous measurement is performed by the proposed method based on multi-recording technology in speckle interferometry. From experimental results, it can be confirmed that the proposed optical system can measure simultaneously in-plane and out-of-plane deformations in high resolution by one camera.     

Review of Electronic Speckle Pattern Interferometry （ESPI） for Three Dimensional Displacement Measurement

Three dimensional（3D） displacements, which can be translated further into 3D strain, are key parameters tor design, manufacturing and quality control. Using different optical setups, phase-shift methods, and algorithms, several different 3D electronic speckle pattern interferometry（ESPl） systems for displacement and strain measurements have been achieved and commercialized. This paper provides a review of the recent developments in ESPI systems for 3D displacement and strain measurement. After an overview of the fundamentals of ESP! theory, temporal phase-shift, and spatial phase-shift techniques, 3D deformation measurements by the temporal phase-shift ESPI system, which is suited well for static measurement, and by the spatial phase-shift ESPI system, which is particularly useful for dynamic measurement, are discussed. For each method, the basic theory, a brief derivation and different optical layouts are presented. The state of art application, potential and limitation of the ESPI systems are shown and demonstrated.     

激光测量技术及其应用

随着现代科技的不断进步，激光技术已渐渐地被人们所接受和认同。激光的应用领域也已十分广泛，几乎涉及到当今科技的各个方面。尤其是在激光加工、激光测量、军事上的应用更是显现出极大的优势与潜力。这里介绍了激光定位传感器原理及其在工业生产中越来越广泛的应用前景。     

Sliding metallic wear test with in-process wear measurement: A new approach to collecting and applying wear data

A wear test is described in which the edge of a hard wedge is loaded against the periphery of a rotating disc of softer specimen material. The applied normal load is kept approximately constant during a test. As the test progresses and the disc diameter is reduced by the wear taking place the wedge moves radially inward. By measuring this inward movement during a test it is shown how the wear can be continually monitored. Results are given and it is shown how these might be applied in practice, taking into account the influence of both surface roughness and lubrication.     

基于ARM920T模块的深孔表面粗糙度检测装置

在汽车工业生产现场,需要一种可对零部件深孔表面粗糙度实施检测的小型仪器。该仪器应能实现多点自动检测、复杂的数据处理、较好的图形显示功能,必要时还应能根据不同工件参数改写测试运行控制程序。过去研制的具有如此多功能的仪器,体积结构均比较庞大,难以在生产现场采用。以ARM920T为核心的嵌入式模块取代一般微型计算机,实现机电结构紧凑的整体设计,可在实现各种复杂功能的同时,降低仪器成本、提高运行可靠性、缩小体积,以适合工业现场使用。文中给出了检测装置的整体设计、嵌入式模块硬件电路接口、多点粗糙度综合参数的描述与计算方法等。该检测装置可对F16mm~25mm长度为120mm~180mm的内孔表面,实施多达32条母线512点的自动检测。经实际测试验证,该检测装置的极限误差小于5%,满足工业生产现场的需要     

应用机器视觉测量成型和铣磨表面粗糙度

基于二维傅立叶变换,提出了与表面粗糙度成单调关系的5个粗糙度特征,应用序贯特征选择方法选择最优的粗糙度特征组合作为三层BP神经网络模型的输入,该方法适用于用非接触机器视觉系统进行成型和铣磨表面粗糙度的测量。     

Design and implementation of a portable electronic system for vehicle-driver-route activity measurement

This paper presents the autonomous, non-intrusive and universal electronic equipment PGAMS: Portable Global Activity Measurement System, which is able to simultaneously measure and synchronously register the treble driver-vehicle-route activity. It allows one to evaluate the direct effect that real road traffic conditions have on environmental pollution. Among the variables to be simultaneously measured are: (a) from vehicle activity: regime engine and temperature, fuel consumption, global position, instantaneous and average speed and acceleration, frontal and lateral inclination; (b) related to route features: weather conditions, slope and camber of the road, traffic density; and (c) derived from driver activity: clutch, throttle and brake pedal actions. The designed prototype can be on boarded in conventional or industrial vehicles, working in both urban and inter-urban conditions. The paper describes the integration with pollutant emissions meters. Besides, it includes experimental results carried out in real traffic conditions relating vehicle-driver-route activity with gasses emissions.     

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。     

Wireless sensor marking and temperature measurement with SAW-identification tags

A wireless sensor marking system based on surface acoustic wave (SAW) identification tags is presented. The proposed solution is compatible with existing measurement systems and can be applied directly in the sensor or by means of a unique sensor identification cable (SIC). The SAW tag operates completely passive, and withstands temperatures up to 400 °C as well as shocks up to 35 000 m/s². It contains a unique serial identification number, which is encoded on the high-temperature stable SAW device by means of metallic reflector gratings. The interrogation unit uses the sensor cable for transmission but is not directly connected to it, thus the identification system can be even used with high impedance measurement equipment, e.g. charge amplifiers. Interrogation is done in frequency-domain based on well-known radar principles and is realized in a low-cost add-on circuit to the existing sensor evaluation circuitry. Furthermore, by simply enhancing the evaluation software, a temperature measurement of the SAW tag itself, and thus often of the sensor or the sensor environment can be done without additional hardware requirements.     

光学互相关测速系统设计与验证

针对两相流颗粒运动速度测量及基于互相关原理设计了双光路激光测速系统。采用搭建的变频电机带动绕丝产生已知旋转线速度的装置开展光学互相关测速验证实验。通过测量绕丝经双光路激光的光强衰减信号,再对两路信号进行互相关分析,从而得到测点绕丝旋转线速度。以电机转速计算的测点绕丝线速度作为参考值进行测量精度验证,得到光学互相关测速方法的测量相对误差在6%以内,验证了光学互相关测速方法的准确性。     

翻车机卸车系统计量用电子轨道衡方案

本文通过对翻车机卸车系统来煤的三种计量方案进行分析,介绍了采用静态轨道衡称重计量的方案和优点。     

基于USB总线的FPGA主控多功能测试系统

在介绍了传统测试系统的基础上,描述了一种基于USB总线的FPGA主控多功能测孽量统。针对传统测试系统的不足,着重论述了高速USB总线硬件、软件的实现及相关FPGA程序的设计。并总结了系统结构紧凑、成本低廉、测试精度高和通用性强等优点。     

High-resolution large-strain measurement of plastically deformed specimen by Fourier phase correlation

The Fourier phase correlation method is applied to position circular marks one by one printed on the specimen before and after deformation in order to measure the large plastic strain. This method is extremely sensitive to the differences between the profile of a mark and noise. Therefore, it detects marks easily even under non-uniform illumination without any processing such as flattening illumination, noise exclusion and boundary enhancement in image transformation into binary codes. In addition, a new method of moving reference images (MRI) to position the observed marks in the sub-pixel range is proposed. The MRI technique introduces the theoretical resolution 1/n (n: number of divisions of one pixel). The MRI method enables the positions of the deformed marks to be determined with a resolution of ±0.1 pixel (standard deviation σ_p is 0.042 pixel). Strain of the tensile specimen can be measured within an error of ±0.0015 (standard deviation σ_ε=0.00055).     

Design and calibration test of a support force measuring system for hypersonic vehicle aerodynamic measurement

With the development of air-breathing integrated vehicle test models equipped with engines, the designing of traditional internal balance force measuring systems has become complicated. This is partly because hypersonic vehicle models have slender bodies, and engine systems inside such model cavities are densely distributed, thereby limiting the space available to house traditional internal balance systems. Moreover, traditional force measuring systems are assembled mechanical systems, and their dynamic force transmission characteristics are inevitably degraded under extremely short test time conditions. Thus, herein, we propose a support force measuring system that integrates the traditional internal balance system with a support in an integral design. The designed internal triangular concurrent force system considerably reduces the additional moment generated by the thrust/resistance force. Calibration tests reveal that the new system demonstrates good linearity and repeatability, and the results prove the correctness of the triangular concurrent force system structure principle.     

In-Process Modelling and Estimation of Thermally Induced Errors of a Machine Tool During Cutting

A compact measurement system was developed to measure the time variant machine tool errors during cutting. The system is composed of a gauge, a sensor holder, 5 gap-sensors and a PC. The gauge is made of invar which has a very low thermal expansion coefficient, and is often used to measure the thermally induced errors of a machine tool. A new neural network model was considered to estimate the time variant machine tool errors during cutting using a new concept of input values. The detail of the model proposed is described in the paper together with experimental methodologies using a compact measurement system to examine the validity of this approach. These schemes were implemented on a small vertical-machining centre.