In modern manufacturing, the in-process measurement of complex surface of cylindrical gear is critical and challenging, and is directly associated with subsequent assembly and terminal gear quality. 3D geometric measurements of gear are ones of the crucial fundamental quantities to ensure their conformity to design specifications serving a range of industries, from shipping, automotive and aerospace industries to house applications. In this paper, an automated sampling path planning model is designed in order to obtain a loss cost sampling path by consider of the complex surface of cylinder gear. The high-precision full information model of tooth flank is also being established, which depends on the measurement procedure and the measurement uncertainty. A series of experiment on several typical cylindrical gears were carried out to demonstrate this automated path planning technique and the final geometric measurement accuracy. On the other hand, an commercial 3D geometric measuring system was also introduced, which has two degrees of laser scanner. Those scanning paths generation have been proven to be amenable for practical purposes through many tests so that it might be applicable to achieve 3D geometric measurements of large gear.
In modern intelligent living, Carbon dots exhibit the great potential by virtue of their unique structure and attractive optical performance serving a range of monitoring and management, from biochemical analysis, biological imaging and environmental monitoring. In this paper, a sub-micro line spacing standard shape was designed based on phosphorescence carbon dots. This spacing standard not only has an unequally spacing line widths, but also shows that the particle size distribution of Carbon dots range from 1.0nm to 10nm. On the other hand, in order to exhibit the potential of our designed shape, a series of experiments were preformed to demonstrate the relationship between fluorescence intensity and special effects. Those results have been proven to be amenable for practical purposes through many tests so that it might be applicable to achieve lighting illumination in different scenes.
In modern intelligent living, X-ray computed tomography (CT) exhibit the great potential in industry for non-destructive dimensional quality control purposes, which serving a range of monitoring and management, from chips, integrated circuits, batteries, and automotive components. In this paper, a special standard sample was designed and manufactured to test critical dimensional characteristics on different CT systems. Additionally, a sequential participation scheme, together with detailed measurement procedures and reporting instructions, has been proposed to evaluate measurement uncertainty and determine metrological performances of CT systems. Finally, a series of experimental tests were carried out to demonstrate dimensional measurement errors of CT systems. Those results have been proven to be amenable for practical purposes through many tests so that it might be applicable to achieve accuracy and traceability issues of CT systems in industrial intelligent production line.
In this paper, a full geometric information measuring model of 3D gear was developed based on laser scanning techniques. In order to generate a optimum sampling path, a measuring cost function was proposed by considered of the relationship among the sampling interval, sampling point clouds, and measurement precision of key features. On the other hand, 3D tooth surface measurement error was described by quantitative point cloud data. A commercial 3D gear measuring system was also introduced, which has a degrees of laser scanner and self-developed special analysis software. Finally, a series of experiments on typical cylindrical gears (base circle diameter from 100 mm to 500 mm) were performed to demonstrate this automated path planning technique, measurement cost, and the full geometric measurement accuracy.
A dual-axis numerical control rotary table is designed in this article to calibrate a dual-axis tilt sensor. The device comprises a swing axis and a rotating axis, which are used to produce tilts in two perpendicular directions. To achieve precise control of the motion mechanism and enhance positioning accuracy, the time-grating angular displacement sensors have been adopted as the feedback and measurement components in both axes of the device. The experimental results indicate that the error of the swing axis of this calibration device is ±1.5 arcsec, while the error of the rotation axis is ±1.0 arcsec, with a repeatability of less than 0.5 arcsec, which is suitable for the calibration of the majority of dual-axis tilt sensors.
In modern manufacturing, the in-process measurement of complex surface of cylindrical gear is critical and challenging, and is directly associated with subsequent assembly and terminal gear quality. 3D geometric measurements of gear are ones of the crucial fundamental quantities to ensure their conformity to design specifications serving a range of industries, from shipping, automotive and aerospace industries to house applications. In this paper, an automated sampling path planning model is designed in order to obtain a loss cost sampling path by consider of the complex surface of cylinder gear. The high-precision full information model of tooth flank is also being established, which depends on the measurement procedure and the measurement uncertainty. A series of experiment on several typical cylindrical gears were carried out to demonstrate this automated path planning technique and the final geometric measurement accuracy. On the other hand, an commercial 3D geometric measuring system was also introduced, which has two degrees of laser scanner. Those scanning paths generation have been proven to be amenable for practical purposes through many tests so that it might be applicable to achieve 3D geometric measurements of large gear
Laser interferometry is a typical representative of the highest level in the field of geometric metrology, and its accuracy can reach sub-nanometer while taking the light wavelength as a measuring scale. In this paper, we present a precisely controlled transmission structure to realize the conversion between angular and linear displacement, therefore the angular displacement can be obtained based on the high-precision linear displacement measured by the laser interferometric system. By comparing the measured angular values with the reference values, the maximum error of angular displacement measurement in this system is ± 5 arcsec, which is from the calibration certification of the National Institute of Metrology. The reference values are obtained by measuring the angular polygon with a photoelectric autocollimator, and an angular displacement measurement error of ±1 arcsec is achieved based on laser interferometric system in this paper after correcting with a series of conversion coefficients between linear and angular displacement.
Scanning electron microscope (SEM) with feature analysis software has been used for micro-scale surface measurement tasks for many years because of the benefits of fast massive acquisition of nano-scale features, non-contact operation, and automatic data processing. Full information of surface usually needs to obtain in some inspection fields, such as vertical engine part monitoring, cleanliness analysis, melted bead and so on. According to the specific measured feature, the depth mode, resolution mode, and analysis mode of SEM should be firstly determined before use. Therefore, it is important to give user an easy operation mode to get deeper understanding on geometric features, thus offering a significantly enhanced user experience and higher measurement accuracy. Several common aspects of operated behavior should be tested that can cause them to yield larger measurement errors. In this paper, the experimental tests of full information acquisition of multi-scale pitches and step heights samples were respectively performed on a commercial SEM. The influence of the depth mode, resolution mode, and analysis mode of SEM were also discussed on edge features. Experimental results show that our works will be helpful of others who perform similar measurements.
Scanning electron microscope have been widely studied in academia and applied in engine wear monitoring, geology, air cleanliness and pollution, because of the benefits of fast massive acquisition of nano-scale features, non-contact operation, and automatic data processing. It is important to have an automated analysis ability to get a deeper understanding on geometric features of multi-regulars shape of different particles, thus offering a significantly enhanced user experience and higher measurement accuracy. Hence, it should be carried out geometric measurement error tests before using. In this paper, several different shapes of particle were introduced to test geometric measurement error on a commercial SEM with specific particle analysis software. Several experimental cases have been designed by considered of practical application and user habits. Specially, the distinguish accuracy rate of a single threshold and multiple threshold were respectively tested by different types of particles. On the other hand, the ability of automatically classification schemes using the chemical and morphological information was taken in account too. Our scope was indeed narrow, but intentionally so. Finally, we found that these work may be of use to others who perform similar
In this context, the present research work aims at studying and developing an innovative approach for automated sampling path model for large simple regularly conical workpiece, which could provide designers easily and rapidly taken. Therefore, our attention is focused on 3D geometric relationships between neighboring end points of edge features of workpiece. An algorithm is proposed to guide the scanner device and move it along the main direction of the plane containing the projection of the next critical end point with the use of geometric properties of previously extracted end points. Thus, an appropriate 3D circular-arc scanning path is on-line automatically yielded step by step by an orderly collection of local connected end points. Finally, a series of experiment on typical conical workpieces are carried out to demonstrate the automated path planning technique and the final sampling quality.
In this paper, an automated edge detection model is developed for large irregular circular using a laser scanning approach. Some key influencing factors, just like surface quality, surface orientation and scan depth, have been respectively considered in this model. By consider of the limited of field of view and corresponding optical constraints, only a small part of key region is effectively captured by laser scanner at a specific posture. In term of specified view angles of laser scanner, the position of laser scanner approximate to the stand-off distance with respect to edge area can be determined and then high-quality point clouds of large irregular circular edge feature can be effectively obtained. Finally, a series of experiments are performed on workpieces with different large irregular circular features. The experimental result shows our method features high automation and high efficiency. Those results are most promising for on-machine applications in dimensional measurement of large-scale workpiece.
In order to meet high quality measurement requirements with less cost and lesser time consumption, the sampling strategy has to be planned before the measuring device is already available. In this paper, a common 3D geometric measuring system based on laser scanning technique is presented. An measurement cost model is established by consider of several cost sources in 3D geometric measurement process. In terms of view angle of laser scanner, an optimal inspection strategy planning is developed on a circular feature too. Finally, a series of experiments on typical circular of workpieces are performed based on coordinate measuring system equipped with a laser line scanner. In case of desired measurement accuracy for the measured feature, the minimum inspection cost can be obtained by the iterative optimization algorithm, thus generating a reliable and an efficient sampling path planning. Those results are most promising for on-machine applications in optimal inspection strategy of 3D geometric of workpiece.
In this paper, a 2-D sizing measuring system of regular particles is developed for characterizing the shapes by simultaneously measuring their length and width. Due to the multi-regulars shape of particles, it is usually required in situ 2D semi-automatic imaging analysis technique to describe their different shapes. In our works, edges of particles in binary image are first detected based on automatic threshold decomposition of the original gray-scale image. Then, the internal holes are filled in some individual detection region. In order to separate from different regular shapes, a selected threshold for the rectangularity filter has been applied. Then, by use of Euclidean distance map (EDM), the size measurement of individual particle is calculated. Finally, a series of experiments on these selected electron micro graphs , which contains particle with sizes from 10nm to 200nm, are respectively carried out to verify the performance of previous image analysis technology on our developed software. Those results are most promising for on-machine applications in naon-dimensional measurement of regular particles.
This article presents a novel automated measurement prototype for 3D geometry of mobile and large-scale conical workpiece, manipulated through two independent robot platforms that placed on its two sides with laser scanner and motorized linear stage. First, with point cloud that covers end point provided by laser scanner. Then, modeling and identification of end point of workpiece is established based on height variations in its nearest neighborhood with respect to virtual measurement datum plane, which is step-by-step derivatively generated according to initial datum point in an online virtual inspection environment. Next, the current geometry-relations between neighboring end points can be subsequently used to guide the laser scanner for high precision sampling surface area incorporating an automatic simple module. Moreover, both orientation and position geometrical relationships of the corresponding features on the fitting circles are analyzed too. Details preliminary experimental tests were performed to verify the measuring accuracy of this method.
Nowadays, 3D geometric dimensional measurements of step height are performed on many types of samples using different instruments, such as AFM, optical microscopy, et.al. For step height measurements generally, the traceability of the z-axis is very importance. In this paper, displacement metrology in the vertical direction or z-axis is first determined, thus having a known and specific relationship between the physical edge on the sample and the location of the detected edge in the image. By consider of the location of the step, a step height is calculated by requirement of fitting to upper and lower surfaces. An algorithm is introduced to fit the upper and lower terraces. Then, we locate the edge and determine the step height by the data extrapolation of those fits. In order to reduce the uncertainty budget for step height measurements, 50nm, 100nm, 200nm, 500nm and 1000nm step height are respectively tested, and dominant sources are also discussed.
Laser interference system has been extensively applied in high-precision geometric metrology benefit from the advantages of high accuracy, high resolution and stability in linear displacement measurement. In this paper, we present a novel and compact mechanical structure to realize the conversion between angular and linear displacement, so that the slight angular displacement can be enlarged and obtained by using the characteristics of high-precision linear displacement measurement of laser interference system. A series of experiments are carried out on this device, the conversion ratio of angular and linear displacement we achieved is 5.76 arcsec/ μm, which is determined by the transmission ratio of the worm gear pair and the pitch of the ball screw. By comparing the measured angular values with 23 reference values distributed on the whole circumference, the maximum original error of angular displacement measurement in this system without correction or compensation is ± 25 arcsec and the resolution is 0.6 arcsec.
Nowadays, in industrial area, many mechanical part manufactures are applying 3D optical scanner in their production shop to do part online inspection, or in their coordinate measurement laboratory to obtain crucial part dimensions. The high demands of the 3D optical scanner make it necessary for researchers to create convenient and stable device for calibrating this kind of contact-less measurement instrument. In a former study, we introduced a plate with standard spheres as a calibration device, which showed a good test result when applied on a 3D optical scanner. However, we decide to do more research on related area. The first purpose of this paper is to present an improved calibration device based on our former study and daily work experience. The new device has a wider test range with less spheres, and it’s structure is more portable, stable and more convenient to provide spatial positions. Results showed that the new device performed well in data stability and is quite easy to practice. The second purpose of this work is to study related influence factors on the 3D optical scanner calibration process. We investigated factors such as temperature, points cloud density, reflection patch density and numbers of images stitching. The results showed that those factors should be limited in proper conditions to ensure an acceptable calibration of 3D optical scanner.
Nowadays, with 3D topographic features increasingly complicated and complex, scanning probe microscopes have widely been used of nano-scale dimensional measurement in the semiconductor manufacturing and space industry, which can create three-dimensional data over almost all solids in a wide range of ambient. Although scanning probe microscopes readily achieve nanometer level resolution images of measured surfaces, there are several aspects of their behavior that can cause them to yield large measurement errors. In this paper, according to possible traceability pathways for calibration of lateral axes and z axis, both pitch and step height measurements are respectively performed and axis error self-correction model is proposed. The influence of thermal stability on drift error is also discussed. Experimental results show that our method will be helpful for a fast performance evaluation test for scanning probe microscope.
A CMM with multiple probing systems have the power to deliver tremendous benefits to most notably manufacturing, and have the advantage of high automation, high integration and high precision. According to the ISO standard 10360-9, multiple probing system location error should be identify and calibrated before use. In this paper, a location error self-calibration model was established based on a composite artifact. The location error of individual probing system can be respectively determined reference to the position of the probe configuration. An error separation procedure was introduced to correct this location error. A series of representative experiments were performed on a commercial combined probing system produced by our partner. The experimental results show that multiple probing systems location error was effectively reduced from 4.5μm to2.8μm. Also, this calibration evaluation is very apparently practical outside a laboratory due to its simple, portable, low-cost, and rational procedure.
This study proposes an experimental method for the performance evaluation of a commercial combined probing system equipped with a contacting probe, an imaging probe, and a line laser scanner developed by our cooperation. According to its application purpose, this method first obtains the circular characteristics of our novel designed 3D artefact composed of 2D rings, cone and cylinders. It is suitable to measure the touch probe, imaging probe as well as optical sensor. Next, detailed measuring procedures were defined for this artifact, in order to achieve comparable results and make the measurements feasible for the different sensors involved. A series of representative experiments were carried out on a commercial combined probing system produced by our partner. The experimental results show that multiple probing system form error and location error were less than 4.0μm, and multiple probing system size error was less than 2.0μm in three different registration positions. System combination errors were less than its maximum permissible errors (MPEs). On the other hand, its root mean errors (RMSE) were less than 0.5μm. Therefore, we can conclude that the designed artifact is suitable to be used to assess the performance of CMMs with multiple probing systems. These conclusions are helpful for further use of this combined probing system and can be utilized to optimize those combined parameters further.
The characteristics of turbidity in the watershed of Chongqing City’s water supply system in interconnected reservoir basins between JiaLingJiang River and Chang Jiang River are investigated and analyzed by dynamic light scattering method (DLS). Three months of continuous turbidity measurements in seven sampling sites along the JiaLingJiang River were respectively performed from March to May in 2018. The experiment results demonstrated that the particles with highly similar light-scattering features are the main contribution to turbidity in the JiaLingJiang River. The analysis of turbidity time series showed that the particle populations from water sources impacts in downstream waters and the influence of urban wastewater pollution and wet weather pollutant was not obvious in those months. On the other hand, the relative errors of turbidity measurement results were always less than 3% with national turbidity standard.
A calibration device for the optical scanner is presented in this paper for the situation that lacking of a convenient calibration method for the optical scanner in domestic industry practice. The device utilized the spherical center distance of fixed balls as standard dimensions. It can provide various dimensions in different orientations and magnitudes since it has nine fixed standard balls in different positions. When we run an actual measurement process on this device with an optical scanner, the indication error of the scanner can be obtained conveniently. The device is simple in structure and easy to operate, it can produce multiple dates in one single measurement process simultaneously, which can evaluate the performance of the optical scanner comprehensively.
A CMM with multiple probing systems have the power to deliver tremendous benefits to most notably manufacturing, and have the advantage of high automation, high integration and high precision. These probing system combinations must be tested to check their compliance with the specifications and to trace back the measurement results. In this paper, we present a novel multi-ring artifact and appropriate test procedures for probing system combinations similar to the well-known test procedures described in the ISO standard 10360-9. The characteristic of multi-rings artifact is keeping topology geometric relationships among 2D rings. Then, a series of representative experiments were carried out on a commercial combined probing system equipped with an imaging probe and a line laser scanner, and results have proved such multi-ring artifact as a fast way for performance test.
This article presents a novel multi-layer artifact for systematic error correction of a gap measuring system, consisting a 3D laser scanner and motorized linear stages. This artifact representation of five-layers gap shape with continuous free-form surface was designed, which include diverse form dimensions. Then, in order to improve the measurement accuracy of the range dimension of the gaps, a one-step calibration procedure based on an experimental process has been developed. The influence of the three parameters on width error, depth error and flush error, defining the relative position and the orientation between the scanner and the range gaps, is respectively considered. The results obtained in accuracy and repeatability tests performed on this multi-layer artifact primitives attest to the viability of this correction method for gap measuring system.
In industrial manufacturing processes, the dimensional inspection of the gaps on the free-form shape parts is critical and challenging, and is directly associated with subsequent assembly and terminal product quality. In this paper, a fast measuring method for automated gap inspection based on laser scanning technologies is presented. The proposed measuring method consists of three steps: firstly, the relative position is determined according to the geometric feature of measuring gap, which considers constraints existing in a laser scanning operation. Secondly, in order to acquire a complete gap profile, a fast and effective scanning path is designed. Finally, the range dimension of the gaps on the free-form shape parts including width, depth and flush, correspondingly, is described in a virtual environment. In the future, an appliance machine based on the proposed method will be developed for the on-line dimensional inspection of gaps on the automobile or aerospace production line.
Non-contact measurement techniques using 3D laser scanning have the power to deliver tremendous benefits to most notably manufacturing, and have the advantage of high speed and high detail output. However, procedures for evaluation and verification of non-contact laser line scanner have not been well-established because of many influencing factors like scan depth, incident angle, probe head orientation and surface properties. A truncated pyramid artifact representation of five- planar with different included angles was designed and used to straightforwardly identify the influence of in-plane and out-of-plane angle, as well as scan depth on dimensional measurement accuracy of the laser scanner. Then, a series of easy, fast and representative experiments, based on this simple artifact, were performed on a commercial laser line scanner, and found that the output of this scanner can be improved for metrology applications after calibration.
Non-contact measurement techniques using laser scanning have the power to deliver tremendous benefits to most notably manufacturing, and have the advantage of high speed and high detail output. However, a major obstacle to their widespread adoption in more complex on-line producing environments is their geometric constraints and low accuracy compared to the contact-based counterparts. The work presented in this paper introduces a performance evaluation test of laser line scanning for in-process inspection of 3D geometries. Some straightforward test methods that use a designed artifact are proposed. First, one work aims to experimentally investigate the location accuracy of knee point or corner point of edge features using a commercial laser stripe scanner, which is common in mechanical parts. Another work experimentally investigates the formation of outliers that may be usually promoted by reflective surfaces around surrounding area of corner point, and these outliers are characterized with large measurement errors, which significantly deteriorate the quality of the scanned point cloud data. Scanning path planning and outlier filter design are respectively discussed.
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