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2020 Vol. 41, No. 10 Published: 2020-10-28

	1177	Error Analysis of Optimizing Manipulator Trajectory Tracking Controller Based on Contraction-expansion Factor
		WANG Hong-tao,JIANG Wen-song,JIANG Qing-ze,ZHANG Qiang,DAI Ning
		DOI: 10.3969/j.issn.1000-1158.2020.10.01
		A variable universe fuzzy controller whose universe can be adjusted by contraction-expansion factor in real time is proposed to optimize the trajectory tracking effect of the manipulator. Firstly, a scale-exponential hybrid contraction-expansion factor whose functional form is related to the dynamic weight of joint-angle deviation and joint-deviation variation is designed. Secondly, the desired joint-trajectory in cartesian space is calculated by using the time-optimal path-following algorithms. Finally, the simulation of the trajectory tracking control of a three-joint manipulator is realized by using the designed variable universe fuzzy controller, and the trajectory tracking error is analyzed further. The simulation results show that the designed variable universe fuzzy controller using scale-exponential hybrid contraction-expansion factor has the advantage of better trajectory tracking control effect, faster response speed, smaller steady-state error and no overshoot.
		2020 Vol. 41 (10): 1177-1183 [Abstract] ( 358 ) HTML (1 KB) PDF (970 KB) ( 378 )

	1184	Trajectory Planning Based on Traceability of Spatial Pose Measurement Equipment
		WANG Xin-rui,XUE Zi,HUANG Yao,ZHANG Fu-min
		DOI: 10.3969/j.issn.1000-1158.2020.10.02
		Under the background of the research on traceability technology of pose measurement equipment, a standard path should be planned to reflect the difference of measurement under the same condition. And in order to design the standard path which has the economic rationality, high efficiency and high accuracy, the influences of different spatial trajectory curves on measuring equipment should be studied, such as laser tracker and visual measurement equipment. The industrial robot was took as the research object, the D-H parameter model of the robot was established, the structure and connecting rod parameters were analyzed, and kinematics equations were derived. The correctness of forward and reverse kinematics of the robot were verified using MATLAB robotics toolbox. The trajectory planning methods were analyzed and simulated in joint space and cartesian space on the basis of the industrial robot kinematics model, such as three times polynomial interpolation method and five times polynomial interpolation method. Through a series of simulations, it is concluded that the method of higher degree polynomial interpolation in joint space for standard trajectory planning can be used. The simulation images can also verify the smooth joint trajectory and ensure the speed and the continuity of the measurements. The analysis and simulations provided the theoretical foundation for the further study of trajectory on the influence of different measuring equipment and standard path planning.
		2020 Vol. 41 (10): 1184-1191 [Abstract] ( 332 ) HTML (1 KB) PDF (2071 KB) ( 317 )

	1192	Application of Improved Genetic Algorithm in CMP Endpoint Detection
		ZHENG Yong-jun,DI Wei-yu,LUO Zai
		DOI: 10.3969/j.issn.1000-1158.2020.10.03
		In order to improve the accuracy and efficiency of chemical mechanical polishing (CMP) endpoint detection, a method based on reflection method for CMP online endpoint determination was proposed. Firstly, the film thickness and refractive index of SiO₂ film were fitted by the improved simplex hybrid genetic algorithm (GA). Secondly, the average reflectance in the range of 200～1200nm was used as the eigenvalue, and a reference table of reflectance average values under different film thickness conditions was obtained. The difference between the real-time reflectance and the preset film thickness reflectance, and the eigenvalue with its changing trend were used as the CMP endpoint detection conditions. The experimental results demonstrate that the average relative error of the hybrid algorithm is less than 0.21%, the average relative error of the refractive index is less than 1.07%, and the eigenvalue calculation speed is fast, which meets the time requirement of online dynamic polishing.
		2020 Vol. 41 (10): 1192-1198 [Abstract] ( 327 ) HTML (1 KB) PDF (0 KB) ( 91 )

	1199	An Automatic Nanometre Particle Size Detection Algorithm for Scanning Electron Microscopy
		WANG Zhi,LI Qi,HUANG Lu,GAO Si-tian,SUN Miao,DONG Ming-li
		DOI: 10.3969/j.issn.1000-1158.2020.10.04
		A new automatic detection method of nano-particle size in scanning electron microscopy (SEM) test is proposed based on mathematical geometry. The method has two different parameters, the ratio of long and short axes and the area of region, which are used to judge whether the particles are clustered or incomplete based on the particle size distribution and shape information in the SEM pictures. And the complete single particles can be get, then use MATLAB to extract the wide edge shape of particles with different size. The pixel value of different particles is obtained by the least square method, and the real value can be calculated with transformation, thus realizing the automatic detection of different particles. The test results of polystyrene nanoparticles were selected to verify the method, which show that the two parameters can accurately and effectively extract single point particles in the case of less incomplete clusters. While the ratio parameter is more accurate if there are more incomplete particles in clusters, and the results of automatic detection are in good agreement with the actual values.
		2020 Vol. 41 (10): 1199-1204 [Abstract] ( 328 ) HTML (1 KB) PDF (1557 KB) ( 557 )

	1205	Using BP Network for Occlusion Boundary Detection Based on Depth Image
		ZHANG Shi-hui,GENG Yong,ZHANG Xiao-wei
		DOI: 10.3969/j.issn.1000-1158.2020.10.05
		Aiming at the occlusion phenomena existing in visual object, an occlusion boundary detection approach is proposed based on machine learning for depth image. Firstly, a novel occlusion related feature named the longest projected line segment is presented according to the depth and spatial information in depth image. Secondly, a nonlinear normalization method is designed to normalize the occlusion related features. Finally, the problem of occlusion boundary detection is taken as a classification problem, meanwhile, the back propagation(BP) neural network is utilized to detect the occlusion boundary and then the detection result is visualized. Compared with existing methods, the proposed approach is more accurate and the generalization performance is better.
		2020 Vol. 41 (10): 1205-1211 [Abstract] ( 317 ) HTML (1 KB) PDF (1392 KB) ( 248 )

	1212	Research on Illumination Test of Vehicle Lamp Module
		XIU Ya-nan,MU Ping-an,DAI Shu-guang,ZHU Wan-yi
		DOI: 10.3969/j.issn.1000-1158.2020.10.06
		In order to solve the problem of distortion caused by the installation position of the camera system when the illumination image of the lamp module is collected, the plane template method is used to correct the distortion of the system through the distortion correction algorithm, so as to reduce the measurement error caused by the distortion of the image coordinate position. In view of the influence of the uneven illumination of the image plane on the gray value of the image, the method of plane template is used to correct the distortion of the system. After the correction coefficient of the camera system is obtained in the illumination uniformity correction experiment, the correction coefficient is processed by the surface fitting method based on the combination of Marquardt method and general global optimization algorithm, and the function model of pixel coordinates and correction coefficient is obtained to realize the correction of image gray value. The calibration of the corrected camera system is carried out to establish the relationship between gray level and illuminance, so as to improve the accuracy of illumination detection of lamp module. The experimental results show that the error of illuminance detection of lamp module is basically controlled within 10%, and the repeatability error is less than 1%, which has high accuracy and reliability.
		2020 Vol. 41 (10): 1212-1217 [Abstract] ( 294 ) HTML (1 KB) PDF (1964 KB) ( 315 )

	1218	Point Cloud Segmentation De-noising Method Based on Curvature Constraint
		ZHANG Yu-cun,LI Ya-bin,FU Xian-bin
		DOI: 10.3969/j.issn.1000-1158.2020.10.07
		In the process of point cloud de-noising, point cloud segmentation de-noising method based on curvature constraint was proposed in order to improve the de-noising effect of the region with larger curvature change. In the mentioned method, curvature constrained point cloud data was used to keep the model features effectively, and noise smoothing mapping function was constructed to make the noise points regress smoothly, which could avoid over-smoothing the point cloud data model by traditional filtering and lay a foundation for subsequent processing. Experiments showed that the above method could effectively preserve the characteristics of the model, retain the edge information of the model, and the de-noising effect was more obvious than bilateral filtering.
		2020 Vol. 41 (10): 1218-1225 [Abstract] ( 303 ) HTML (1 KB) PDF (1731 KB) ( 683 )

	1226	Automatic Detection of Internal Defects in Freshwater Nucle-free Pearls Based on OCT
		SHI Long-jie,ZHOU Yang,CEN Gang,LIU Tie-bing,SHI Yang,CHEN Zheng-wei,HUANG Jun,WANG Feng-lin,CEN Yue-feng
		DOI: 10.3969/j.issn.1000-1158.2020.10.08
		Optical coherence tomography(OCT)isthe high resolution and nondestructive optical inspection method whichhas been used to evaluate the internal quality of pearls. In order to expand the range of applications of optical coherence tomography technique, an automatic detection method for internal defects of freshwater nucleated pearls by optical coherence tomography is proposed. According to the grayscale change of defect layer, the proposed method extracted the gradient feature and defect location feature of the defect region in the image, and then established the back propagation neural network(BPNN)model for defection prediction based on the extracted feature. Twenty optical coherence tomography images of defect pearls and twenty optical coherence tomography of images of health pearls were collected for image preprocessing and feature extraction in experiments, and K-means algorithm test was used to test the feature compatibility, andthe compatible features were the input of the back propagation neural network model which finally classified the defect recognition. The experimental results show that the matching degree of feature extraction is 92.5%, and the classification accuracy is up to 100%, which proved the feasibility and effectiveness of proposed method, and showed the proposed method can be used as an effective method for the identification and classification of internal defects of freshwater pearls.
		2020 Vol. 41 (10): 1226-1233 [Abstract] ( 324 ) HTML (1 KB) PDF (3421 KB) ( 266 )

	1234	Development of a High-performance Amplifier for Johnson Noise Thermometer
		HAN Qi-na,ZHOU Kun-li,QU Ji-feng,DONG Xian-ying,ZHANG Jian-qiang,LI Jing-hui,WANG Miao-er
		DOI: 10.3969/j.issn.1000-1158.2020.10.09
		A amplifier with low-noise, low-distortion, and high common-mode rejection ratio (CMRR) is critical for the noise thermometer. A high-performance amplifier for noise thermometers composed of three stages of preamplification, instrumentation amplification and buffer amplification is designed. An ultra-low noise junction-field-effect-transistor (JFET) pair IF9030 is used as the input of the pre-differential amplifier stage. An instrument is developed to automatically measure the transfer characteristics of the JFET pair, so as to achieve a better matching of the characteristics. Cross-correlation technologies are performed to suppress the uncorrelated noise in the circuit, thus the nonlinear distortions under the background noise could be accurately measured. The results show that the background noise of the amplifier is about 1.2nV/Hz1/2. The CMRR within 100kHz is higher than 90dB, and in the 100kHz to 1MHz, the CMRR decreases to lower values with the frequency increasing. fortunately, it is still larger than 70dB even at frequencies close to 1MHz. When the amplifier is excited by a two-tone signal with a frequency of 400kHz, 401kHz and an effective amplitude of 8μV, the second-order intermodulation distortion and the second-order harmonic distortion are 79dB and 85dB lower than the fundamental, respectively.
		2020 Vol. 41 (10): 1234-1239 [Abstract] ( 357 ) HTML (1 KB) PDF (1352 KB) ( 514 )

	1240	Uncertainty Evaluation on Temperature Sensor’s Dynamic Response Based on Water Facility
		LIU Bo,WANG Chong-yuan,ZHU Peng-fei
		DOI: 10.3969/j.issn.1000-1158.2020.10.10
		For nuclear fast response temperature sensor re-test, the calibration facility of temperature sensors dynamic response in flowing water was established. The calibration uncertainty of every factor was evaluated. In the small time region, approximate linearity between voltage and time exists, indicated by oscilloscope. Based on the approximation, uncertainty propagation was realized from temperature to time parameters. Uncertainty evaluation was conducted for a nuclear fast response platinum resistance temperature sensor’s calibration. The result showed that the expanded uncertainty of time constant was U=27ms (k=2). The oscilloscope cursor resolutions of voltage and time are the important factors for the uncertainty. The results can provide reference for the re-test procedure.
		2020 Vol. 41 (10): 1240-1244 [Abstract] ( 301 ) HTML (1 KB) PDF (612 KB) ( 550 )

	1245	Correlation Flow Measurement Method for Gas-Liquid Two-Phase Flow Based on Tomography
		TONG Wei-guo,ZHU Geng-hong,GU Hao
		DOI: 10.3969/j.issn.1000-1158.2020.10.11
		Applying electrical resistance tomography and wavelet texture features of images, based on tomography to realize the measurement of liquid phase flow, a gas-liquid two-phase flow-related flow measurement method is proposed. And the gas phase flow rate is obtained by using electrical resistance tomography and related algorithms to detect the phase ratio and transit time of different bubble types. Besides, the streamline texture features of the tomography are extracted by wavelet analysis. Based on BP neural network, the relevant flow measurement model of gas-liquid two-phase flow under different bubble types is established. The experimental results show that the measurement accuracy of the liquid flow can reach within 3%.
		2020 Vol. 41 (10): 1245-1251 [Abstract] ( 278 ) HTML (1 KB) PDF (0 KB) ( 107 )

	1252	Effect of Sample Tilt on Measurement of Friction Coefficient by Microscratch Test of Copper with a Spherical Indenter
		LIU Ming,HUANG Cheng-xin,GAO Cheng-hui
		DOI: 10.3969/j.issn.1000-1158.2020.10.12
		The microscratch test of copper was carried out by a spherical indenter, and the effect of sample tilt on the measurement of friction coefficient was studied under constant normal load. The results show that the nominal friction coefficient measured in the experiment is linearly related to the tilt angle, and the difference of ±9° will cause the friction coefficient to differ by about 14 times. By establishing the position relation model between the spherical indenter and the inclined state of the sample, it is found that the inclination of the sample has almost no effect on the adhesion friction coefficient, but the plowing friction coefficient changes linearly with the tilt angle. In order to accurately calculate the true friction coefficient under non-tilting condition, the conversion between the nominal friction coefficient and the true friction coefficient can be realized by the flat-on-flat type contact mechanics model. Another way is to reciprocate at different positions on the surface of the sample, and the average value is used as the final result.
		2020 Vol. 41 (10): 1252-1259 [Abstract] ( 301 ) HTML (1 KB) PDF (1199 KB) ( 217 )

	1260	Rolling Bearing Fault Diagnosis Based on Ensemble Empirical Mode Decomposition and K-Singular Value Decomposition Dictionary Learning
		LI Ji-meng,LI Ming,YAO Xi-feng,WANG Hui,YU Qing-wen,WANG Xiang-dong
		DOI: 10.3969/j.issn.1000-1158.2020.10.13
		The morphology of atom in dictionary constructed by the K-singular value decomposition algorithm is affected by noise and harmonic interference, which reduces the extraction precision of the fault feature. To solve this problem, a method of impulse feature extraction based on ensemble empirical mode decomposition and K-singular value decomposition dictionary learning is proposed to realize the fault diagnosis of rolling bearing. Firstly, ensemble empirical mode decomposition and Hurst exponent are used to preprocess the vibration signal to remove the harmonic interference; Then, the preprocessed signal K-singular value decomposition algorithm is learned by K-singular value decomposition algorithm to construct the over-complete dictionary; Next, the dictionary is analyzed K-means clustering algorithm to remove the atoms with smaller kurtosis values; Finally, the orthogonal matching pursuit algorithm is used to realize the sparse representation of impulse fault features. Experiments analysis and engineer application verify the effectiveness and practicability of the proposed method.
		2020 Vol. 41 (10): 1260-1266 [Abstract] ( 263 ) HTML (1 KB) PDF (671 KB) ( 557 )

	1267	Electric Car Motor Bearing Fault Feature Frequency Extracting Method Based on LCD and LLTSA
		SHI Su-min,YANG Chun-chang,WANG Fei
		DOI: 10.3969/j.issn.1000-1158.2020.10.14
		In order to extracting electric car motor bearing fault feature frequency effectively, a fault feature frequency extracting method of electric car motor bearing based on local characteristic-scale decomposition (LCD) , linear local tangent space algorithm (LLTSA) and envelope spectrum analysis is introduced. Firstly, electric car bearing original fault signals are decomposed into several intrinsic scale component (ISC) with different frequency band components through LCD. And then, the LLTSA was used to reduce the dimension of the matrix construct by ISC components, and then a new fault signal can obtain by a low dimension matrix which obtained by LLTSA. Finally, the fault frequency can be identified accurately by the envelope spectrum. The experimental results of simulation signal and experiment signal show that the proposed method can identify different state effectively and has a certain superiority.
		2020 Vol. 41 (10): 1267-1272 [Abstract] ( 290 ) HTML (1 KB) PDF (741 KB) ( 225 )

	1273	Measurement Uncertainty Evaluation for Calculation Factor of the Road Dynamic Deflection
		DOU Guang-wu,MIAO Na,LIU Lu,ZHANG Bing
		DOI: 10.3969/j.issn.1000-1158.2020.10.15
		The deflection calculation factor is an important technical index of the FWD accuracy. In order to evaluate the measurement uncertainty of the deflection calculation factor, the definition of deflection calculation factor was determined, and the measurement model was established, the standard deflection sensor, FWD measurement repeatability and linear fitting model were determined as the three main uncertainty components, and the foundation deflection and environmental conditions of the calibration environment were recommended. The experiment result showed that the expansion uncertainty of the deflection calculation factor of the FWD with stable performance was generally between 1.0% and 3.0%, and the linear fit slope was the main influence factor for the measurement uncertainty of the deflection calculation factor.
		2020 Vol. 41 (10): 1273-1278 [Abstract] ( 301 ) HTML (1 KB) PDF (549 KB) ( 244 )

	1279	The Pilot Comparison Calibration of Vector Receivers in the Frequency Range 5 Hz to 10 kHz
		CHEN Yi,JIA Guang-hui,FEI Teng,Isaev A E,Matveev A N
		DOI: 10.3969/j.issn.1000-1158.2020.10.16
		Using three vector receivers VHS56, VHS90 and KPG-10 as reference vector receivers, the comparison calibration of vector receivers in the frequency range 5Hz to 10kHz was performed between HAARI, China and VNIIFTRI, Russia . The sensitivities of X, Y and Z channels of three vector receivers were calibrated by free-field reciprocity calibration facilities and vertical standing wave tube comparison calibration facilities of HAARI and VNIIFTRI. The calibration results of two participants were consonant with each other. There was only one frequency points deviation between calibration results and reference values slightly exceeding the reference expand uncertainties in all 174 calibration frequency points, and the deviations at most frequency points were less than ±0.5dB, which tested and verified the correction and reliability of the calibration results of vector receivers given by both participants international calibration facilities.
		2020 Vol. 41 (10): 1279-1283 [Abstract] ( 355 ) HTML (1 KB) PDF (1777 KB) ( 310 )

	1284	Fault Prediction of Wind Turbine Gearbox Based onLong Short-term Memory Network
		HE Qun,YIN Fei-fei,WU Xin,XIE Ping,JIANG Guo-qian
		DOI: 10.3969/j.issn.1000-1158.2020.10.17
		To capture the characteristics of dynamic temporal-spatial correlation hidden in monitoring data of wind turbine gearbox, a fault prediction method based on long short-term memory (LSTM) network is proposed. The proposed approach mainly consists of two phases: offline training and online detection. First, the oil temperature of the gearbox is taken as the modeling variable and the LSTM-based normal behavior model of wind turbine gearbox oil is built based on historical monitoring data training and learning, which fully takes advantages of the important correlated information between the oil temperature and some relevant input variables. Then, the model residuals are calculated and evaluated to determine the corresponding detection threshold. Furthermore, the well-trained LSTM model is used for online testing.Through model residual analysis and threshold comparison, fault detection and prediction of wind turbine gearbox can be realized.A real motoring data from a wind farm is used to validate the effectiveness of the proposed method. The results show that compared with those traditional methods, the proposed method presents better prediction performance, and can predict the occurrence of gearbox failure earlier.
		2020 Vol. 41 (10): 1284-1290 [Abstract] ( 318 ) HTML (1 KB) PDF (1204 KB) ( 3555 )

	1291	Design of River Water Quality Monitoring SystemBased on Beidou Communication
		YAO Yue,YU Li-juan,CAO Shou-qi,CHEN Cheng-ming,ZHANG Bing-yi
		DOI: 10.3969/j.issn.1000-1158.2020.10.18
		In view of the current time-consuming and laborious problem of water pollution monitoring, and realizing real-time online detection of water quality information, a buoy monitoring system based on Beidou communication is proposed, which includes a buoy body data acquisition system and a shore-based receiving station system. The data acquisition system with the newly designed buoy as the carrier adopts the STM32 chip, reads the sensor data through the RS485 protocol, sends it to the SD card, and sends the data to the shore base through the Beidou module. The shore-based host computer can be viewde remotely buoy status data, water quality data, and location information. The entire system uses solar power to complete data collection, data storage, data transmission, and data processing. After testing, the whole system is in good working condition, and the water quality can be automatically monitored to meet the expected design requirements.
		2020 Vol. 41 (10): 1291-1296 [Abstract] ( 302 ) HTML (1 KB) PDF (2033 KB) ( 462 )

	1297	Comparative Research on Two Methods of Measurement Data Processing for Average Glandular Dose
		ZHAO Cai-xian
		DOI: 10.3969/j.issn.1000-1158.2020.10.19
		Focusing on the difficulties that exist in the data processing of the AGD measurement of medical X-ray radiation source for mammographic equipment, two effective data processing methods were proposed: the nearest value method and the linear fitting method. Through test and comparison, the following conclusions were obtained: the measurement results and uncertainty obtained by the two data processing methods meet the requirements of relevant technical specifications, and satisfied the judge standard of 3Urel≤MPE. In comparison, the measurement results obtained by linear fitting method are more accurate, its relative expanded uncertainty (k=2) is in the range of 5.7%～6.5%, while that obtained by the nearest value method is in the range of 6.4%～10%. The above two data processing methods can effectively solve the problem of how to determine the conversion factor of different phantom thickness and the correction factor of different breast components in the verification of medical breast X-ray radiation source, and provide some reference for the next revision and improvement of national regulations, and also have a certain reference for the analysis and processing of other similar measurement data.
		2020 Vol. 41 (10): 1297-1302 [Abstract] ( 302 ) HTML (1 KB) PDF (484 KB) ( 180 )

	1303	Free Air Ionization Chamber for the Absolute Measurement of Synchrotron Radiation X-ray Fluence
		WANG Pei-wei,ZHENG Wei-ning
		DOI: 10.3969/j.issn.1000-1158.2020.10.20
		According to the relationship between the photon flux, fluence and air kerma of X-ray beam, the required photon flux and fluence were determined through the measurement of air kerma. It is based on the principle of X-ray free-air ionization chamber, and aiming at the physical conditions of synchrotron radiation photon beam, the scheme and design of free-air chamber were determined and the precise processing and adjustment were completed. The dimensional tolerance, mechanical properties and electrical properties of the main parts of the ionization chamber meet the requirements of metrological standards. It provided a basis for the establishment of metrological standards. The main parts size and tolerance as well as mechanical and electrical properties, to meet the requirements of metrological standards. It provides the foundation for the establishment of metrological standard.
		2020 Vol. 41 (10): 1303-1307 [Abstract] ( 347 ) HTML (1 KB) PDF (993 KB) ( 312 )

	1308	Research on Characterization Method for Library DNA Reference Material for Next Generation Sequencing
		WANG Xia,OUYANG Yan-yan,WANG Jing,WANG Shang-jun,DONG Lian-hua
		DOI: 10.3969/j.issn.1000-1158.2020.10.21
		Next generation sequencing (NGS) have been increasingly used in many applications. The accuracy of quantification of DNA library can directly affect the quality of the sequencing data. Thus, it is very important to develop DNA library quantification quality control method. A SYBR Green dye based digital PCR method was established to characterize the DNA library quantification reference material for Illumine NGS platform. The suitability of the proposed reference material was evaluated. The result showed that it is fit for the purpose of usage as standard curve to quantify the DNA library for illumina NGS.The results showed that the five levels of library quantitative reference materials have good linearity, and can be used as the standard curve to quantify the DNA library for Illumina NGS.
		2020 Vol. 41 (10): 1308-1312 [Abstract] ( 287 ) HTML (1 KB) PDF (1580 KB) ( 317 )

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