Non-contact Measurement Technology Research Articles

Research on High Temperature Protection Technology of Infrared Temperature Measuring Equipment in Space Environment

With the increasing complexity of spacecraft structure and thermal design, it is more difficult to implement surface temperature measurement technology, and the temperature measurement area tends to diverse. Therefore, there is an increasing demand for the application of non-contact temperature measurement technology in spacecraft thermal test. This paper takes the application of infrared temperature measuring equipment in vacuum and high temperature environment as the research object, designs the thermal protection scheme and device of the equipment, and simulates and analyses the thermal protection of infrared temperature measuring equipment based on node network method. Through physical test, the device can effectively realize the thermal protection of equipment in vacuum and high temperature environment, and ensure that the equipment is in the normal working temperature range and its temperature measurement algorithm model is not affected, the accuracy of temperature measurement is better than ±2°C, which meets the use requirements in spacecraft thermal test.

Using the entropy of the corneal pulse signal to distinguish healthy eyes from eyes affected by primary open-angle glaucoma

Objective: The purpose of this study was to evaluate whether the complexity of the corneal pulse (CP) signal can be used to differentiate patients with primary open-angle glaucoma (POAG) from healthy subjects. Approach: The study sample consisted of 28 patients with POAG and a control, age-matched group of 30 subjects. After standard ophthalmic examination, the CP signal from a randomly selected eye of each participant was measured using non-contact ultrasonic micro-displacement measurement technology. After pre-processing, the complexity of the CP signal was estimated using refined composite multiscale fuzzy entropy (RCMFE) up to scale factor 50. The average RCMFE values were computed from three repeated measurements of the CP signals for each participant and each scale factor. Main results: The complexity of the CP signal in glaucomatous eyes was higher than that observed in healthy ones. Also, RCMFE of the CP signal was found to differentiate (statistically significantly) between the two groups for scales in the range from 26 to 43. For these scales, the one for which the lowest p-value (t-test, p = 0.017) was obtained when comparing RCMFE between the two groups was selected as the optimal scale. Next, a receiver operating characteristic analysis for the optimal scale showed that the proposed approach of calculating the multiscale entropy of the CP signal has some potential to discriminate between patients with POAG and healthy controls (sensitivity, specificity and accuracy of 0.643, 0.700 and 0.672, respectively). Significance: In conclusion, RCMFE, as a complexity measure, may be considered an auxiliary indicator to support glaucoma diagnostics.

A novel NURBS surface approach to statistically monitor manufacturing processes with point cloud data

As sensor and measurement technologies advance, there is a continual need to adapt and develop new Statistical Process Control (SPC) techniques to effectively and efficiently take advantage of these new datasets. Currently high-density noncontact measurement technologies, such as 3D laser scanners, are being implemented in industry to rapidly collect point clouds consisting of millions of data points to represent a manufactured parts' surface. For their potential to be realized, SPC methods capable of handling these datasets need to be developed. This paper presents an approach for performing SPC using high-density point clouds. The proposed approach is based on transforming the high-dimensional point clouds into Non-Uniform Rational Basis Spline (NURBS) surfaces. The control parameters for these NURBS surfaces are then monitored using a surface monitoring technique. In this paper point clouds are simulated to determine the performance of the proposed approach under varying fault scenarios.

An Improved Multiple Signal Classification for Nonuniform Sampling in Blade Tip Timing

Blade tip timing (BTT) is an effective noncontact measurement technology for rotating blade health monitoring. However, due to the mismatching between the high-speed rotation and the limited amount of probes, the signal collected from the BTT system is severely undersampled, which induces the difficulty in feature extraction. Multiple signal classification (MUSIC) has the potential to overcome the undersampled problem once the probes are properly placed. Whereas, if traditional MUSIC is directly used in BTT, the accuracy of frequency identification cannot be high enough and the identified number of frequency components is also severely restrained. To address these two problems, an improved MUSIC is proposed as an alternative methodology to extract the blade vibration frequency for BTT. Based on the orthogonality of the signal subspace and the noise subspace from undersampled signal, the presented method can effectively identify the vibration frequency components from the undersampled signal of BTT.

Space Point Target Ranging System Based on Laser Beam Triangulation

With the rapid development of ranging technology, people’s requirements for ranging technology are more and more high. In some special occasions, such as live, high temperature, explosive and other inconvenient scenes, the importance of non-contact ranging technology is highlighted. As a non-contact measurement technology, laser ranging technology has faster measurement speed, higher measurement accuracy, longer measurement distance and stronger anti-interference ability compared with other measurement methods. However, at present, the measurement accuracy of laser ranging technology in China is not very high, and the design is relatively complex. Aiming at the above problems, this paper designs a spatial point target ranging system based on laser beam triangulation. The system uses the combination of laser ranging module and angle sensor module to measure the distance, uses the laser axis angle algorithm based on triangle method to calculate the distance, and uses the pyboard development platform to design the simultaneous acceptance and processing of multiple serial port data, and finally displays the measured data through the display. The experimental results show that the system can measure the distance between two points in space with relative error less than 1%, and it has the functions of circle and quadrilateral perimeter measurement, continuous measurement distance and data storage, which can meet the ranging requirements in various fields of engineering.

Critical compressive strain and interfacial damage evolution of EB-PVD thermal barrier coating

The durability evaluation of electron beam physical vapor deposited (EB-PVD) thermal barrier coating (TBC) systems is one of the critical issues in engineering applications. The interfacial toughness degradation as a function of the thickness of thermally grown oxide (TGO) was investigated through isothermal oxidation and cyclic oxidation tests for single-crystal superalloy specimens with an EB-PVD TBC. The critical strain criterion of TBC compression spalling was proposed through compression tests at room temperature according to noncontact full-field strain measurement technology and the digital image correlation (DIC) method. Based on a simplified mechanical model of TBC systems and elastic buckling theory, the interfacial damage was described by the critical compressive strain at spallation considering residual stress in the ceramic top coat (TC). The results indicated that the damage induced by cyclic oxidation is greater than that induced by isothermal oxidation at the same TGO thickness, showing additional damage induced in thermal cycles. Then, a new TBC life prediction model based on the nonlinear accumulation of oxidation damage and cyclic damage was developed, and the error between the damage prediction and the testing results was found to be no more than ±10%.

Summary of developing a test stand for realistic emulation of the cross-sectional area variation of hot rolled wire

Abstract The development of innovative measuring technology for process optimization in hot rolling mills becomes more and more relevant because of increasing demands on product quality. Measurement technology for high-resolution non-contact cross-sectional area measurement has shown that the variation in cross-sectional area contains information about the rolling process. This information can be used for the development of new measurement devices and analytical methods for process optimization. The harsh environmental conditions and strict safety regulations result in great effort when implementing a new sensor prototype in hot rolling mills. For this reason, this work presents a mechatronic test stand that can simulate the cross-sectional area variation under laboratory conditions realistically.

A Displacement Frequency Response Function‐Based Approach for Locating Damage to Building Structures

Frequency response function (FRF) data can provide considerably more information on damage in the desired frequency range as compared to modal data extracted from a very limited range around resonances. Among structural health monitoring techniques, FRF‐based methods have the potential to locate structural damage. Conventional structural damage detection technology collects structural response data using contact systems, such as displacement or acceleration transducers. However, installing these contact systems can be costly in terms of labor, cost, and time. Several noncontact measurement technologies, such as optical, laser, radar, and GPS, have been developed to overcome these obstacles. Given the rapid advances in optical imaging hardware technology, the use of digital photography in structural monitoring systems has attracted considerable attention. This study develops a displacement FRF‐based approach to locate damage to building structures. The proposed damage location index, CurveFRFDI, improves the sensitivity of SubFRFDI, which is a substructure FRF‐based damage location index proposed by Lin et al. (2012). Moreover, the feasibility of applying the proposed approach to locate damage to building structures using displacement measured by a digital camera combined with digital image correlation techniques is also investigated in this study. A numerical example and an experimental example are presented to demonstrate the feasibility of using the proposed approach to locate damage to building structures for single and multiple nonadjacent damage locations.

Experimental Study on the Cable Tension Based on Non-Contact Dynamic Deflection Equipment

For the contact and wired measurement technology of cable tension, the factors of complicated bridge site conditions, data acquisition and transmission, wave data processing and sensor contact should be considered in practical application, which affect seriously the measure result accuracy, work efficiency and the measure feasibility. In order to improve the limitation of the existing cable tension measurement technology, the feasibility and key factors of non-contact dynamic deflection measurement technology is studied. A cable specimen with length of 12m was designed and made, and the steel strand is used in it, and the non-contact vibration testing device is used. The frequency and tension of the cable and the strain of steel strands are analyzed, and the results show that the effect of measure target position on the fundamental frequency of the cable is obviously little, and the tension of the subsequent steel strand can decrease the tension strain of the stretched steel strand, that is, the tension of the stretched steel strand is reduced. Furthermore, the maximum difference between calculated and measured tension of the cable is about 17.7% during loading stage. When the unloaded cable tension is less than 20.6%, the difference between calculated and measured tension is less than 10.0%. It can be seen that the tension and tension loss of the cable can be accurately estimated by using the non-contact dynamic deflection technology, and it can improve the work efficiency and the measure feasibility due to the less measure targets and larger data transmission distance.

Dynamically Modulated GaN Whispering Gallery Lasing Mode for Strain Sensor

AbstractThe continuous development of strain sensors offers significant opportunities for improving human–machine interfaces and health monitoring. The dynamically modulated lasing mode is a novel approach to realize a flexible, noncontact, high color‐resolvability, high‐resolution, and ultrasensitive strain sensor. Here, a flexible strain sensor perceiving stress variations is reported via the dynamical regulation of a GaN whispering gallery lasing mode based on the piezoelectric effect. The refraction index of GaN shows a linear relationship with the applied external tensile strain, resulting in a redshift phenomenon of the lasing mode peak at room temperature due to the predominant function of the piezoelectric polarization in the GaN microwire. Compared with a strain sensor relying on the wavelength shift of a photoluminescence (PL) emission peak, the differences and advantages of a sensor based on the strain‐induced lasing mode variation are also investigated and analyzed systematically. This strain sensor may serve as an essential step toward the color mapping of mechanical signals by optical methods, with potential applications in color‐perceived touching sensing, noncontact stress measurement, laser modulation, and optical communication technologies.

Development of Hydrogen Gas Non-contact Concentration Measurement Technology for Micro-area Observation

Development of Hydrogen Gas Non-contact Concentration Measurement Technology for Micro-area Observation

Analysis of Deformation Law of Tunnel Surrounding Rock based on Visualization of Rock Mass Structure

In order to accurately obtain the characteristic parameters of the rock mass structural plane of the tunnel and provide effective basis for numerical calculation, based on tunnel of Guiguang railway, this paper measured the structural characteristics of typical tunnel side wall and excavating face by using Sirovision non-contact measurement technology of 3d photogrammetry and accomplished digital geological logging, information statistics of structural plane attitude, rock stability analysis. By using the discrete element software UDEC, the whole process of tunnel excavation, primary support and secondary lining are simulated. The study show that the surrounding rock deformation, internal force of primary support, axial force of anchor bolt will improve with the increase of fragmentation degrees of surrounding rock. The primary support is the determinant of constraint of surrounding rock deformation and bearing the load after tunnel excavation. Secondary support only as a permanent support structure, as a safety margin, the internal force is small compared with the primary support, but taking into account the decreasing of physical and mechanical parameters of the surrounding rock excavation, rheology of soil and reducing of mechanical properties of primary support material. The secondary lining should be calculated and designed as force structure.

Morphology Evaluation of Microelectronic Packaging Substrates Using Shadow Moiré Technique

The surface quality and long-term reliability of packaging substrates in microelectronic packaging processes have become subjects of increasing concern as circuit board component density increases while the pitches of these components decrease. As a result, packaging substrate morphology inspection is becoming more crucial than ever before. This paper presents a noncontact measurement technology based on a shadow moire technique to evaluate the surface quality and morphology of microelectronic packaging substrates. Fringe pattern images of packaging substrates are acquired through the noncontact measurement technology, and the resulting images are then analyzed using the phase-shifting technique to determine the morphology and surface quality (specifically, the flatness) of the microelectronic packaging substrates. A full-field morphology measurement system with adjustable sensitivity and measurement range was developed. The measurement system was tested using three typical types of microelectronic packaging substrate, a coin and a step made from two standard gauge blocks. The measurement system proved to be both feasible and effective by the test results.

Hydrogen gas concentration measurement in small area using raman lidar measurement technnology

When change of hydrogen(H2) gas concentration in a certain point is measured, non-contact measurement technology with high temporal and spatial resolution is necessary. In this study, H2 concentration in the small area of <1cm2 under the gas flow was measured by using a Raman lidar. Raman scattering light at the measurement point of 750mm ahead was detected by the Raman lidar. As a result, it was proved that the H2 concentration of more than 100ppm could be successfully measured.

A microscopy approach for in situ inspection of micro-coordinate measurement machine styli for contamination

During the process of measurement using a micro-coordinate measurement machine (µCMM) contamination gradually builds up on the surface of the stylus tip and affects the dimensional accuracy of the measurement. Regular inspection of the stylus for contamination is essential to determine the appropriate cleaning interval and prevent the dimensional error from becoming significant. However, in situ inspection of a µCMM stylus is challenging due to the size, spherical shape, material and surface properties of a typical stylus. To address this challenge, this study evaluates several non-contact measurement technologies for in situ stylus inspection and, based on those findings, proposes a cost-effective microscopy approach. The operational principle is then demonstrated by an automated prototype, coordinated directly by the CMM software MCOSMOS, with an effective threshold of detection as low as 400 nm and a large field of view and depth of field. The level of contamination on the stylus has been found to increase steadily with the number of measurement contacts made. Once excessive contamination is detected on the stylus, measurement should be stopped and a stylus cleaning procedure should be performed to avoid affecting measurement accuracy.

An Experimental-Computational Correlated Study for Describing the Failure Characteristics of Concrete across Two Scale Levels: Mixture and Structural Component

The failure characteristics of concrete, which are often brittle, are complex due variability in mix design, heterogeneity of the final man-made composite product, and the complexity associated with describing the corresponding mechanical response across different scale levels. Numerous experimental methods as well as numerical models have been developed to characterize the mechanical behavior of cementitious composites, but the major of these methods have focused on describing bulk response and are not well suited to characterize localized phenomena. Recent advances in the areas of multi-scale modeling and computational mechanics have shown promise for improving current capabilities, but these approaches also require experimental validation. This manuscript explores the extension of Digital Image Correlation (DIC) to fully characterize the behavior of concrete across different structural scales. The investigation leverages results from an experimental testing program at both mixture and structural member scale levels to evaluate the performance of two representative plasticity-based numerical models commonly used to describe the failure characteristics of concrete subjected to various states of stresses. The experimental study consisted of a series of compression, split tensile, and flexural tests. For the numerical models, the finite element method (FEM) was used to simulate concrete specimens at different scale levels. A comparison of the experimental and numerical results demonstrated that the numerical models are capable in predicting the ultimate capacities and global responses of the tested specimens. The minimum discrepancy between the results was observed in the pure compression tests, with less agreement observed in the presence of tensile stresses (i.e. split tensile and flexural tests at both scale levels). This can be attributed to the limitations of the selected material models in describing the tensile behavior of concrete beyond the elastic limit as well as the current shortcomings associated with numerical analyzes and their capabilities in describing the localized behavioral features such as crack initiation and propagation. Results from this investigation highlight the potential of DIC as a non-contact measurement technology to improve the performance of existing material models for traditional civil engineering materials, but also underscores its capabilities in development of new constitutive models for the next generation of innovative high performance materials.

Crack and crack growth behavior analysis of asphalt mixtures based on the digital speckle correlation method

Cracking is one of the main reasons for asphalt pavement damage. Because of the anisotropism of asphalt mixtures, traditional experimental methods cannot analyze displacement and strain fields accurately. A full-field, noncontact measurement technology—the digital speckle correlation method (DSCM)—is a good method to analyze the deformation characteristics of asphalt mixtures. By using DSCM and a semi-circular bending (SCB) test, the crack initiation and propagation rules can be tested experimentally; the full-field displacement and strain can be analyzed by vic-3D software. The results show that the strain field (Exx) and the rate of change displacement field (dU/dt) are well suited to study the properties of crack and fracture characteristics of asphalt mixtures. The interface between asphalt binder and stone is the weakest part of the entire structure, and comparing the crack growth rate and load displacement curve of a crumb-rubber (CR) modified asphalt mixtures and a styrene-butadienestyrene (SBS) modified asphalt mixtures, it is found that the carrying capacity of a CR modified asphalt mixtures is stronger than that of a SBS modified asphalt mixtures.

航摄与机载激光雷达技术在河道地形测量中的应用

随着数字航空摄影及激光雷达技术的发展，这种非接触式测量技术成本低、快速高效、机动灵活的优势也越来越显著。结合长江干流1:10,000河道地形测量项目，介绍了航空摄影及激光雷达技术相结合的作业方式及其在大面积的洲滩、植被高覆盖河道地形测量中的应用情况，并对成图精度进行了检测分析，结果表明成果精度满足相关规范要求，这种联合作业模式应用于河道地形测绘中是可行的。 With the development of digital aerial photography and lidar technology, because of its low cost, high efficiency and flexible, this non-contact measurement technology is becoming more and more significant. Based on the 1:10,000 riverway topographic survey project of Yangtze River, we introduced the operation mode of aerial photography and lidar technology and the application of riverway topographic survey in a large bottomland and high vegetation coverage area, and statistically analyzed the accuracy of topographic map. The results show that the surveying precision satisfies the requirements of relevant specifications, and this combined operating mode used in riverway topographic Survey is feasible.

磁気センサによる非接触高精度電流検出技術

磁気センサによる非接触高精度電流検出技術

Wykorzystanie optycznej metody analizy odkształceń do oceny wybranych własności wytrzymałościowych materiału próbki drukowanej metodą FDM

Wykorzystanie optycznej metody analizy odkształceń do oceny wybranych własności wytrzymałościowych materiału próbki drukowanej metodą FDM