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2019 Vol. 40, No. 6
Published: 2019-11-22
 
941 Research in the structure design and sensing characteristics of the filament-surface capacitive sensor
ZENG Tao,LU Yun-feng,ZHANG Zhong-hua,CHEN Le,XU Su-an
DOI: 10.3969/j.issn.1000-1158.2019.06.01
A filament-surface capacitive sensor based on self-damping vertical reference to measure the residual horizontal displacement precisely during the vertical movement is presented. The filament electrode works as a direct vertical reference, which avoids the system error caused by indirect-reference conversion. And the liquid damper in the end of the filament electrode ensures the stability of the capacitive sensor. Experiments show that in the range of 0.38~0.4pF, the resolution of the filament-surface capacitive sensor is better than 0.05μm, and the short-term stability is approximately 0.1μm.
2019 Vol. 40 (6): 941-945 [Abstract] ( 334 ) HTML (1 KB)  PDF (1223 KB)  ( 530 )
946 A New Method for the Measurement of Time Constant of Low Value Wide Band Non-inductance Current Shunt
PAN Yang,ZHOU Li-ren,FENG Jian
DOI: 10.3969/j.issn.1000-1158.2019.06.02
Wide band non-inductance current shunt was widely used in the field of high voltage impulse and high frequency harmonic of the electrical system. The bandwidth of the current shunt was depended on its time constant which contribute to the measurement uncertainty evaluation. The current shunt time constant was determined by least square fitting method to calculate the inductance of current shunt. A high precision multi-meter was employed to measure DC resistance of current shunt. The input of square wave and the output voltage of the current shunt were measured by synchronized digital sampling. Two equivalent cables were connected to the output of signal generator in order to minimize time delay, the influence of impedance matching on the difference between square wave voltage caused by cable resistance and the input terminal voltage of shunt was studied. The result showed that the proposed method can be used to directly measure the inductance and time constant of the low value non-inductance current shunt with resistance value below 1Ω and bandwidth below 10MHz. The traceability problem of wide frequency current sensor and the wide bandwidth non-inductance current shunt was successfully solved with the proposed method.
2019 Vol. 40 (6): 946-951 [Abstract] ( 287 ) HTML (1 KB)  PDF (764 KB)  ( 321 )
952 Research on the Testing of Adhesive Defects of Aeronautical Composites Based on ECT
JI Yan-yong,LIU Ya-nan,DENG Chen-xiao,YAN Chao-qi,CHEN Xi-yuan
DOI: 10.3969/j.issn.1000-1158.2019.06.03
To solve the problem of defects during the process of production and service of aviation composite materials, a nondestructive testing method based on capacitance sensing principle that consists of a same side multi-electrode array sensor was proposed. Based on the edge effect of capacitance, a set of identical electrode array system was designed to detect the adhesive defects, the true distribution of defects in aerospace composites was simulated. The electrical capacitance tomography system worked in single electrode excitation mode, and according to the change of capacitance value caused by the change of dielectric properties of defects, the system used the conjugate gradient algorithm to detect the location and shape of the defects. The experimental results showed that the mentioned method can accurately determine the location and size of the defects, and detect the defects of 8mm adhesive structure inside the carbon fiber composite with 2mm thickness, and the images of ECT detection system were clear with less edge artifacts. The method provided a new research direction for the development of the detection of defects in composite materials.
2019 Vol. 40 (6): 952-957 [Abstract] ( 267 ) HTML (1 KB)  PDF (917 KB)  ( 537 )
958 Multi-sensor Human Activity Recognition Based on Attention Model
WANG Jin-jia,ZHOU Ya-qian,HAO Zhi
DOI: 10.3969/j.issn.1000-1158.2019.06.04
The deep recurrent neural network was suitable for processing time series data. However, the feature extraction ability of traditional recurrent neural network was poor, and the time dependency mining was insufficient. In response to the mentioned problem, three models of attention mechanism and long-term short-term memory (LSTM) neural network were proposed for human activity recognition application problems. The effects of these three mechanisms on the accuracy of the models were studied separately and in combination with different datasets. In the UCI_HAR data set, the accuracy rates of the three attention LSTM models were 94.13%,95.15% and 94.81%, respectively, which were higher than the identification accuracy rate of LSTM model (93.2%). In addition, for the label characteristics of sensor time series data for human activity recognition, it was proposed to convert the time segment classification task into a segmentation task. Therefore, two attention-based gate recurrent unit(GRU) models based on segmentation tasks were designed. The accuracy of Bahdanau attention GRU model were 84.61% and 89.54% in the Skoda data set and the opportunity data set which were higher than the benchmark UNet model’s 70.40% and 88.51%.
2019 Vol. 40 (6): 958-969 [Abstract] ( 355 ) HTML (1 KB)  PDF (1357 KB)  ( 890 )
970 Measurement Uncertainty Evaluation for the Laser Small Angle Primary Standard
WANG Han-bin,HUANG Yao,XUE Zi,HOU Jia,WANG Chao-yang
DOI: 10.3969/j.issn.1000-1158.2019.06.05
Based on transparent box model, using the Monte Carlo method, the measurement uncertainty of the laser small angle measurement system was evaluated. According to the measuring principle, the evaluation model for the measurement uncertainty was built, the sources of uncertainty were analyzed. The influence of the zero-angle positionand the measured angle on the measurement uncertainty was emphatically analyzed. The analysis results show that the measurement uncertainty is mainly affected by the random error when the measured angle is small. The measurement uncertainty increases with the increasing of the measured angle. When the zero-angle position is not accurately adjusted, the measurement uncertainty is no longer subject to the normal distribution, and its influence increases with the increase of the measured angle.
2019 Vol. 40 (6): 970-974 [Abstract] ( 337 ) HTML (1 KB)  PDF (1416 KB)  ( 315 )
975 Study of Temperature States Influence on the Accuracy of Large Size Measuring Devices
LI Ting,LI Jian-shuang,MIAO Dong-Jing,LI Lian-Fu,LIU Xue-de
DOI: 10.3969/j.issn.1000-1158.2019.06.06
Large-scale measuring device has a wide measuring range, the measurement accuracy of the device is affected by many factors, among them, the change of the environmental conditions of the large size measuring device will affect its measurement accuracy. Based on the indoor 80m length standard device of National Institute of Metrology, China, the measurement accuracy experiment of 10m, 30m, 70m in the air conditioning temperature control state and natural temperature state (not controlled temperature) were designed to study, the refractive index compensation errors in the air-conditioning temperature control state were 7.0μm, 10.5μm, and 21.0μm, and the refractive index compensation errors in the natural temperature state were 2.5μm, 2.9μm, and 3.9μm respectively. The experimental results show that the large-scale measuring device can obtain higher measurement accuracy under natural conditions, and when the measuring range is greater than 30m, the measurement accuracy can be better than 10-7 magnitude.
2019 Vol. 40 (6): 975-979 [Abstract] ( 314 ) HTML (1 KB)  PDF (1015 KB)  ( 327 )
980 Flatness Error Evaluation Based on Grouped Particle Swarm Optimization Algorithm
BI Li-heng,ZHU Yan-qi
DOI: 10.3969/j.issn.1000-1158.2019.06.07
Flatness error is determined based on grouped particle swarm optimization(GPSO).Firstly,mathematic model of flatness error evaluation was established, and flatness error minimum was transmuted into nonlinear optimization problem of objective function.Secondly, GPSO was divided one PSO into two, which wasn't increased particle number and dimension, and one searched global, the other searched local, threshold was prevented premature.Finally, the process was given.The simulation results show that GPSO has a strong ability of optimization, and the optimal solution value of the test function is relatively small, the tolerance value of flatness is 0.0073mm, the average tolerances of GPSO are reduced 0.0023mm,0.0025mm,0.0027mm,0.0002mm and 0.0005mm comparing with LSM, DM, TPM, PSO and ABC,and the precision is higher than others algorithms.
2019 Vol. 40 (6): 980-985 [Abstract] ( 297 ) HTML (1 KB)  PDF (1425 KB)  ( 259 )
986 Weather Classification of Sunny or Cloudy Day Based on an Outdoor Color Image
ZHANG Shi-hui,DU Xue-zhe,HE Qi,DONG Li-jian
DOI: 10.3969/j.issn.1000-1158.2019.06.08
A novel approach to classify whether an outdoor color image is sunny or cloudy is proposed by using random forest. Firstly, two new weather features named sky frequency histogram and shadow energy are defined respectively, and their calculation methods are presented. Meanwhile, the transmission feature is introduced in weather classification for the first time. These three features are combined with the existing features to form the candidate weather feature set. Secondly, a new feature importance calculation method named Fisher-Random Forest is proposed to select weather features. Finally, the selected weather features are input into the random forest classifier in the form of vector to classify whether the outdoor color image is sunny or cloudy. The experimental results demonstrate that, compared with other methods, the proposed approach has higher accuracy and better generality.
2019 Vol. 40 (6): 986-993 [Abstract] ( 296 ) HTML (1 KB)  PDF (1979 KB)  ( 294 )
994 Parameter Optimization Design of Air-floating Platform System for Optical Testing Instrument of Liquid Crystal Glass Panel
ZHOU Yang,LI Cheng-wei,XU Xiao-bo,ZHANG Yong,HUANG Bin
DOI: 10.3969/j.issn.1000-1158.2019.06.09
During the on-line detection of liquid crystal glass plates, the distribution of the pressure and the velocity in the gas film flow field are required to be gentle and the stability. In order to compare the effects of different air-floating platforms on the stability of the gas film, combined with the gas lubrication theory, the pressure distribution of the stable gas film was obtained. The through holes were generally arranged in an array on the air floating plate. Gambit was used to mesh the three-dimensional model of the air-floating platform, and then introduced into the Fluent software to simulate the positive pressure air supply mode and the positive and negative pressure air supply mode. The distribution of the air buoyancy and velocity were obtained under two different air supply modes. From the above analysis, if the remaining variables in the air-floating system remain unchanged, the advantages of positive and negative pressure at the same time of gas supply are more obvious, and the air buoyancy and velocity distribution are smooth after the gas film is stabilized, and the mass flow rate of the required gas is less than that of the positive pressure. Based on the above research, a glass substrate optical defect detection prototype was fabricated by positive and negative pressure simultaneous gas supply. The experimental results show that the change of film gap is less than 1μm and the stability is good.
2019 Vol. 40 (6): 994-999 [Abstract] ( 260 ) HTML (1 KB)  PDF (591 KB)  ( 341 )
1000 Research on 3D Model Acquisition SystemBased on Multiple View
CAO Wen-yi,CHEN Ji-min,YUAN Yan-ping,LIU Si-da
DOI: 10.3969/j.issn.1000-1158.2019.06.10
A new 3D model acquisition system is designed based on multiple view used the technology of 3D scanner and stereo vision, 3D model collection can be conducted using one camera combined with basic mechanical system. 3D model acquisition system was used for calibration experiments and the experimental results shown that the mean deviation in circumferential direction Rr=0.94 and in line direction Rl=0.87 which can meet the accuracy requirement in 3D printing reverse engineering areas. 3D model acquisition system based on multiple view can perform high accurate collecting task at low-cost compared to traditional system. This achievement was the foundation work to the depth study of 3D model acquisition system.
2019 Vol. 40 (6): 1000-1005 [Abstract] ( 370 ) HTML (1 KB)  PDF (1094 KB)  ( 447 )
1006 Target Tracking Algorithm Based on Hybrid Correlation Filtering and Information Fusion Redetection
CHEN Wei-dong,CHEN Lei,DENG Zhi-wei,LIU Hong-wei,DONG Hui-ru,ZHU Qi-guang
DOI: 10.3969/j.issn.1000-1158.2019.06.11
In order to reduce the influence of target deformation and complex background changes on the tracking effect during target tracking, a target tracking algorithm based on hybrid correlation filtering information fusion redetection is proposed.Firstly, the correlation filtering algorithm is used to extract the HoG feature of the target gradient histogram, the color template is used to obtain the color feature of the target, and the sampling score of the two templates are calculated.Secondly, the two feature information is combined in a linear combination to determine the target position, during the tracking process, two templates are selected to sample a larger score according to the set threshold condition and then redetect the position of the target.Finally, it outputs results for all the frame target positions.Compared with other excellent algorithms, the algorithm has better tracking effect on dealing with target deformation and background clutter.
2019 Vol. 40 (6): 1006-1012 [Abstract] ( 303 ) HTML (1 KB)  PDF (2091 KB)  ( 360 )
1013 Color Difference Detection of Polycrystalline Silicon Cells Based on Support Vector Machine Classification Strategy
GUO Bao-su,WU Wen-wen,FU Qiang,WU Feng-he
DOI: 10.3969/j.issn.1000-1158.2019.06.12
Aiming at the problem of color difference detection on polycrystalline silicon cells under complex color and texture characteristics, a new method based on support vector machine classification strategy is proposed to detect the color difference of polycrystalline silicon cells. Firstly, color model conversion and channel separation are performed on the pre-processed cell images. The Otsu method is used to perform threshold segmentation processing on the single-channel image, and the region contrast of each threshold image is calculated, and then an appropriate threshold image is selected according to the regional contrast condition. The image features are extracted by the information provided by the threshold image. Finally, the support vector machine classifier is used to determine whether the cell has a color difference defect. The experimental results show that the proposed color difference detection algorithm can achieve high-efficiency detection of color difference defect, and the accuracy, false detection rate and detection time reach 96.88%, 5% and 109 ms.
2019 Vol. 40 (6): 1013-1019 [Abstract] ( 279 ) HTML (1 KB)  PDF (1097 KB)  ( 546 )
1020 Research on Image Preprocessing Method of Infrared Camera Based on NETD
GAO Yi-fan,CAI Jing,ZHANG Xue-cong,ZHANG Yang
DOI: 10.3969/j.issn.1000-1158.2019.06.13
Noise equivalent temperature difference (NETD) is an important parameter of infrared thermal imager, which can reflect the noise characteristics of the infrared detector. On the basis of eliminating invalid pixels, the image of the thermal imager raw data is preprocessed by linear filtering, nonlinear filtering, histogram equalization and multi-scale image enhancement. Using the direct observation of the image quality and image details by the experimenter as the qualitative criterion and the noise equivalent temperature difference as the quantitative criterion to comprehensively evaluate the advantages and disadvantages of the image preprocessing algorithm. It is found through experiments that the multi-scale image enhancement method after linear filtering can make the image details clearer, and the noise equivalent temperature difference is reduced by about 25.9%, which is the most suitable image preprocessing method for experimental infrared camera.
2019 Vol. 40 (6): 1020-1024 [Abstract] ( 283 ) HTML (1 KB)  PDF (744 KB)  ( 758 )
1025 Research on Hysteresis of the High-precision Thin-film Platinum Tesistance Thermometers
ZHANG Heng,ZENG Fan-chao,WEN Chang-jun,HAO Xiao-peng,SUN Jian-ping,FU Cheng-yu
DOI: 10.3969/j.issn.1000-1158.2019.06.14
Hysteresis is one of the sources of the measurement uncertainty of industrial platinum resistance thermometers(IPRTs). Eight high-precision platinum resistance thermometers(PRTs) were selected to study the influence of the measurement uncertainty due to the hysteresis. The temperature range was between -50℃ and 150℃, and three temperature span thermal hysteresis experiments were carried out. Two standard methods were used to get the thermal hysteresis values which were the change of resistance at the triple point of water and at the midpoint in the temperature range. The experimental results showed that the influence of thermal hysteresis of four thin-film PRTs increases with the increase of temperature range span under the two standard methods, the largest thermal hysteresis measured by IEC 60751 standard method was 14.2mK, and the maximum thermal hysteresis measured by ASTM E644 standard was 20.5mK. The maximum thermal hysteresis measured by the IEC 60751 standard method and the ASTM E644 standard method was 1.1mK and 0.9mK, respectively, when the four platinum wire PRTs were measured at a temperature range of -50℃ to 150℃. The platinum wire PRTs has significantly lower thermal hysteresis than the thin-film PRTs.
2019 Vol. 40 (6): 1025-1029 [Abstract] ( 283 ) HTML (1 KB)  PDF (1880 KB)  ( 436 )
1030 Measurement of In-plane Directional Thermal Diffusivity Using Pulsed Eddy Current Thermography
YU Kai-ke,TIAN Yu-peng,WANG Ping,YIN Xiang-jie,JIA Xing-wei,DONG Shi-yun
DOI: 10.3969/j.issn.1000-1158.2019.00.15
To measure the in-plane directional thermal diffusivity of the conductive material, a new method called pulsed eddy current thermography is proposed. Eddy current along a certain direction is induced on the surface of the conductive material by using an inductive pulsed line excitation to achieve local heating. Under non-steady conditions, simply changing the relative position between the sample and the coil can quickly and non-destructively measure the diffusivity in the vertical direction of the coil. The in-plane heat conduction and the Gaussian temperature distribution are analyzed on the condition of the inductive pulsed line excitation. The AISI304 stainless steel, pure iron, and pure nickel are measured and the measurement results are in accordance with the literature values, all the deviations are less than 9.0% and the relative extended uncertainty is 3.18%,3.72% and 3.70% respectively.
2019 Vol. 40 (6): 1030-1036 [Abstract] ( 291 ) HTML (1 KB)  PDF (1606 KB)  ( 321 )
1037 Research on the Application of the Intelligent Replacement Type Thermostatic Bath Measurement System
YANG Huan-cheng
DOI: 10.3969/j.issn.1000-1158.2019.06.16
According to temperature value of the high temperature end of heat meter and the characteristics of temperature cycle control in the verification process, an intelligent replacement thermostatic tank and application system for temperature measurement were developed.By setting up a group of water tanks and electronic control components, rapid switching of water temperature points was ensured in high temperature water constant temperature tank to meet the requirements of rapid verification of heat meters.The practical principle and method of the intelligent replacement type constant temperature tank and the practical operation guidance of control system were given.The system used the self-made numerical control technology, takes the reference slot as the main measuring body, assisted the tank to prefabricate the constant temperature medium, and build the replacement platform for the intermediate slot.The experimental results showed that the equipment meet the requirements of JJF 225—2001 《Heat Meter》, GB/32224—2015 《Heat Meter》, JJF 1030—2010 《Measurement and Test Norm of Thermostatic Bath′ Metrological Characteristic》and JJF (Mongolia) 033—2018 《Replacement Type Thermostatic Bath Calibration Specification》.The rapid measurement of the temperature can be realized in the heat meter verification process by this method, and the verification efficiency was also improved about one time.
2019 Vol. 40 (6): 1037-1042 [Abstract] ( 278 ) HTML (1 KB)  PDF (1779 KB)  ( 242 )
1043 Phase Volume Fraction Measurement of Gas-liquid Two-phase Flow Based on Near-infrared Surface Source Sensor
FANG Li-de,WANG Shao-chong,WANG Pei-pei,WANG Song,WANG Dong-xing,ZHENG Qing-long,LI Xiao-ting
DOI: 10.3969/j.issn.1000-1158.2019.06.17
Aiming at the problems of traditional near-infrared point-to-point probe sensor measurement blindness and low data accuracy, a gas-liquid two-phase flow phase content measurement device based on near-infrared surface source sensor was proposed and designed. The device effectively reduced the refraction and reflection of near-infrared light and improved the accuracy of the measurement. The flow state of the fluid in the pipeline was simulated by CFD fluid simulation software, and the structure of the device was simulated and optimized. Based on the single-phase flow experiment, the dynamic experiment of gas-liquid two-phase flow was carried out, and the relationship between the four-way near-infrared signal and the phase-containing ratio was obtained. The phase-containment rate measurement model was established, and the phase-inclusive rate measurement was obtained by data import correction model analysis. The relative error is within ±3.5%.
2019 Vol. 40 (6): 1043-1049 [Abstract] ( 244 ) HTML (1 KB)  PDF (723 KB)  ( 468 )
1050 Simulation Study on Gas-liquid Two-phase Flow in the Horizontal-baffle Type Surge Tank Based on the Volume of Fluid Model
YU Lu-jun,HOU Song-liang,MA Yu-ming,CAO Jiu-ying
DOI: 10.3969/j.issn.1000-1158.2019.06.18
For the horizontal-baffle type surge tank of the water flow standard facility, a computational fluid dynamic model was established on the basis of the Navier-Stokes equations. The numerical simulation of the two-phase flow field characteristics in the surge tank was achieved through the turbulence model and volume of fluid transient model, by applying the finite volume method for performing discretization, and standard wall function for modification in the near-wall region. The calculated results showed that, the water flow in the empty tank passes through the following states: anhydrous state, jet flow, upper backwater, overflow and steady state. Meanwhile, aerated flow and bubble flow were formed. In the case of gas-liquid ratio 13, there was a phenomenon of water sloshing in the flow filed of the tank with fixed period, and a vortex gas chamber was formed in the upper side which rotates counter clockwise. The flow field was characterized by lower turbulent viscosity, relatively uniform distribution and best stable performance.
2019 Vol. 40 (6): 1050-1056 [Abstract] ( 279 ) HTML (1 KB)  PDF (1717 KB)  ( 307 )
1057 Design of EGR Adjustable Dual Array Sensor Based on ECT
MA Min,FAN Guang-yong,WANG Tao
DOI: 10.3969/j.issn.1000-1158.2019.06.19
For the traditional ECT sensors electrode-to-gap ratio (EGR) is fixed and can not be adjusted, the distance between the measuring plate and the center of the pipe cannot be changed, the measured objects position and size in the pipe can not select the appropriate electrode-to-gap ratio, and it can not get better reconstructed image. A novel sensor system with adjustable electrode-to-gap ratio is proposed. The electrode-to-gap ratio can be adjusted from 101 to 61. In order to solve the problem that this sensor system can not join the radial substrate and cause the interference of the coupling capacitances between adjacent plates, A system for adding a differential electrode between the measuring plate and the shield was designed, and the differential electrode was adjusted synchronously with the measuring electrode.. The experimental results showed that the selected electrode-to-gap ratio (EGR) would be different along with the difference of the position and the size of the measured object. This sensor system can quickly adjust the appropriate duty cycle to obtain the best imaging effect, the image error (IME) decreased to 0.25 and the correlation coefficient increased (CORR) to 0.80.
2019 Vol. 40 (6): 1057-1063 [Abstract] ( 277 ) HTML (1 KB)  PDF (1812 KB)  ( 218 )
1064 Research and Development of Dual-channel Medical Syringe Pump Automatic Calibration System
SUN Lei,SUN Bin,ZHAO Yu-xiao
DOI: 10.3969/j.issn.1000-1158.2019.06.20
To solve the problems of low efficiency, low detection accuracy, temperature deviation and data batch processing in the manual calibration process of medical infusion pump, an infusion pump automatic calibration scheme based on indirect flow method was proposed. The volume of the specific glass tube segment was calibrated through experiments to obtain the cumulative flow volume, and the accumulative time was obtained by measuring the time of filling the calibrated volume when the infusion pump was automatically calibrated. Thus a dual-channel medical infusion pump automatic calibration system was designed, which can perform error and repeatability analysis and uncertainty evaluation of the measurement results and give a calibration report. The verification experiment shows that the relative error of the automatic calibration system can reach less than 2%, meeting the requirements of 5% of the relevant specifications. The system can repeatedly measure the accuracy of the same infusion pump at different flow rates, which can also use dual channels to simultaneously perform flow calibration tests on multiple infusion pumps, as well as to calibrate the blocking alarm condition of the infusion pump.
2019 Vol. 40 (6): 1064-1070 [Abstract] ( 275 ) HTML (1 KB)  PDF (929 KB)  ( 349 )
1071 Dynamic Calibration Method of Dual-wheel Friction Tester′s Measuring Model Based on Co-excitation Source
JING Gen-qiang,GUO Hong-bo,LIU Lu,DUAN Fa-jie,ZHANG Bing
DOI: 10.3969/j.issn.1000-1158.2019.06.21
To characterize the measurement model of dual-wheel friction testers, the dynamic calibration method based on co-excitation source was proposed. In the method, counterforce constraint based dynamic calibration device was used for data collection, then data sequences matching was done, and mapping relation between the dataset of the objective sensor and that of the reference sensor was obtained. Finally, the parameters of measurement model were confirmed by grouping regression analysis and 2D optimization. The experimental results showed that the proposed method can achieve dynamic calibration of the dual-wheel friction tester′s measurement model with good adaptation to the variation of its state of motion. The residual sum of squares of fitting with the proposed method was reduced by over 50% comparing with the globle least square method.
2019 Vol. 40 (6): 1071-1076 [Abstract] ( 256 ) HTML (1 KB)  PDF (1134 KB)  ( 311 )
1077 Research on Fault Diagnosis of Rolling Bearing Based on Empirical Mode Decomposition and Principal Component Analysis
WANG Chao-hai,CAI Jin-hui,ZENG Jiu-sun
DOI: 10.3969/j.issn.1000-1158.2019.06.22
In order to solve the problems of low efficiency and long diagnosis time of traditional vibration signal feature extraction, a rolling bearing fault diagnosis method based on empirical mode decomposition and principal component analysis were proposed. Firstly, the empirical mode decomposition was used to decompose the vibration signal into a finite number of intrinsic mode functions and a residual function to extract the energy of the main intrinsic mode functions and their local average frequency characteristics. Finally, the composite feature vector was used as the input of principal component analysis classifier to complete the fault identification. The experimental results showed that the composite eigenvector can effectively reflect the running state of the bearing. Compared with BP neural network, support vector machine and K-nearest neighbor algorithm, principal component analysis classification not only can accurately identify faults, but also has the advantages of short training time and convenient use.
2019 Vol. 40 (6): 1077-1082 [Abstract] ( 317 ) HTML (1 KB)  PDF (654 KB)  ( 1879 )
1083 Fault Diagnosis of Rolling Bearing Using Mahalanobis-Taguchi System Based on IVMD
CHEN Jian,ZHUANG Xue-kai,LV Wu-yang,TAO Shan-yong,WANG Wei
DOI: 10.3969/j.issn.1000-1158.2019.06.23
Aiming at the sensitivity and reliability of the single characteristic parameters of rolling bearing operation signal to early faults, a rolling bearing fault diagnosis method based on IVMD and Mahalanobis-Taguchi system was proposed. The method firstly determined the number of layers of the variational modal decomposition based on the spectrum correlation coefficient; and secondly, the modified variational mode decomposition was used to decompose the mechanical vibration signal to obtain a series of band-limited intrinsic mode functions, and calculated the characteristic statistical components of each modal component. Then, the base space of the MTS system on this basis was built. The SNR method was used to screen effective feature variables, and the benchmark space of MTS system was rebuilt. Finally, the Mahalanobis distance from the diagnostic signal to the reference space was calculated to detect the initial fault, and the diagnostic control index of the early fault of the rolling bearing was established.
2019 Vol. 40 (6): 1083-1087 [Abstract] ( 265 ) HTML (1 KB)  PDF (1269 KB)  ( 417 )
1088 Study on the Simulation and Test Method of Static Characteristics for Series Brake Valve
HU Xiao-feng,JIANG Wen-song,GUO Bin,ZHAO Jing,LUO Zai
DOI: 10.3969/j.issn.1000-1158.2019.06.24
The static characteristics of the series brake valve are applied to evaluate the relationship between the output pressure of an air-brake system and the brake stroke during the state of braking balance. The effect of the structural on static characteristics was analyzed by a parameter model based on the AMEsim. A static response process of the series brake valve was built both by its industry standards and the working principle of the linear load system in a simulation environment. In order to reproduce the response process under braking state, a measurement system of static characteristics for the series brake valve was designed by LabVIEW platform utilizing a high-accuracy data acquisition system. Both the MSA and comparative analytical method were introduced to verify the reliability of the system. The experimental result show that the measurement ability index Cg is less than 1.67, and system accuracy indexes are less than 30%, which meet the acceptance requirements of new equipment.
2019 Vol. 40 (6): 1088-1095 [Abstract] ( 294 ) HTML (1 KB)  PDF (1899 KB)  ( 233 )
1096 Indoor Pass-by Noise Measurement Method Based on Acoustic Array Technology
LIU Ce,CHEN Jian,LI Jia-zhu
DOI: 10.3969/j.issn.1000-1158.2019.06.25
The study of indoor pass-by noise test based on acoustic array technology was carried out. The synthetic algorithm of acoustic array signal was established. In view of the problem that the vehicles running state is different from the outdoors when the pass-by noise is tested indoors. A method for getting correct loading parameters of the chassis dynamometer by modifying the coast-by speed range was proposed to ensure the indoor vehicle running state agrees with the outdoors. Finally the absolute error between the indoor and outdoor pass-by noise test results was within±1dB.
2019 Vol. 40 (6): 1096-1100 [Abstract] ( 310 ) HTML (1 KB)  PDF (1461 KB)  ( 190 )
1101 The Precise Measurement Method for Delay of Amplifiers Based on Four-parameter Sinusoidal Curve-fit Method
LIANG Zhi-guo,WANG Ya-ting,WU Ya-hui
DOI: 10.3969/j.issn.1000-1158.2019.06.26
Aiming at the problems in measurement of delay time of amplifiers, such as the large difference between two sampling signals, a novel measurement method based on four-parameter sinusoidal curve-fit method was presented. Based on turning the phase difference into time difference, the delay of amplifiers was measured. Some problems about measurement were discussed. They were the coarse errors of periodic phases, big errors of negative amplitude, modification of delay between two sampling channels of data acquisition its self, all of them were discussed and analyzed in details, and the resolution method were given out. The measurement uncertainty was analyzed. In experiment, both the validity and the feasibility of the measurement method were proved. The experiment showed that the delay of amplifiers has inherence stability itself, it is indifferent to the stimulus frequency, amplitude, and waveforms. The delay measurement method above can be applied in all the measurement of delay of the amplifiers, filters, attenuators, etc.
2019 Vol. 40 (6): 1101-1106 [Abstract] ( 256 ) HTML (1 KB)  PDF (595 KB)  ( 347 )
1107 Inter-laboratory Comparisons of Standard Facilities for Short Pulse E-field
JIANG Ting-yong,YAN You-jie,LIU Xiao-long,MENG Cui,JIANG Yun-sheng
DOI: 10.3969/j.issn.1000-1158.2019.06.27
The short pulse E-field standard facility based on monocone was developed. The inter-laboratory comparison between Northwest Institute of Nuclear Technology, All-Russian Research Institute for Optophysical Measurements and Department of Engineering Physics of Tsinghua University were held in China and Russia which aim to verify the veracity of the standard facility. The equivalent area of transfer standard (D-dot) was calibrated in three standard facilities. Test results show that the waveforms of the D-dot sensor measured in the three laboratories are consistent with the excitation waveforms at the given position of α=70°, r=0.6m in monocone, and the difference of the effective area of the sensor is less than 2%. The comparison results verify that the monocone generates short electromagnetic pulse standard field and can be used for antenna time-domain calibration.
2019 Vol. 40 (6): 1107-1111 [Abstract] ( 280 ) HTML (1 KB)  PDF (994 KB)  ( 291 )
1112 Research and Implementation on Algorithm for Entry Fence Detection of Satellite Positioning Terminal
ZHU Jiang-miao,ZHANG Jing,HUANG Yan,JIN Sen-lin,GAO Chun-liu
DOI: 10.3969/j.issn.1000-1158.2019.06.28
The algorithm for detecting whether an equipment terminal with satellite positioning is within the set range or not deserves attention, which is the decisive factor in the design of an electronic fence. An algorithm for entry fence detection based on support vector machine using classification method was proposed. The algorithm mainly consists of three parts: selecting an appropriate kernel function according to the location data of the satellite positioning terminal; calculating the values of kernel function and error penalty parameters through grid searching technique; adjusting threshold value until the detection accuracy is highest. The validity of the algorithm was demonstrated using experimental data from satellite positioning terminals. The detection accuracy rate is estimated to be 80%～96%, which is much higher than the accuracy of 43%～67% obtained by direct detection. The result embodied high practical value for the society.
2019 Vol. 40 (6): 1112-1116 [Abstract] ( 248 ) HTML (1 KB)  PDF (837 KB)  ( 539 )
1117 Dynamic Calibration Technology of Beidou Receiver Based on Rocket Skid
LI Na-na,PENG Jun,YE Jian-feng
DOI: 10.3969/j.issn.1000-1158.2019.06.29
A dynamic calibration technique of Beidou receiver based on rocket sled test was proposed. By expounding the dynamic calibration process, the standard trajectory establishment method of the rocket sled test, the receiver dynamic positioning and speed error assessment method, the traceability of the external measurement parameters of the rocket skid test and the uncertainty evaluation method of the calibration process, a metered traceable rocket sled test system was established, and the calibration results of the two receivers were analyzed. The results showed that the rocket sled test can effectively solve the high dynamic calibration problem of Beidou receiver, which has certain application value and expansion prospects.
2019 Vol. 40 (6): 1117-9 [Abstract] ( 306 ) HTML (1 KB)  PDF (548 KB)  ( 367 )
1124 Measurement and Uncertainty Analysis of Absorbed Dose to Water of High-energy Photons in Medical Accelerator
WANG Zhi-peng,WANG Kun,JIN Sun-jun,YANG Xiao-yuan,FAN Yao-dong,ZHANG Jian
DOI: 10.3969/j.issn.1000-1158.2019.06.30
In view of the doubts in the use of 60Co absorbed dose to water calibration factor in the ionization chamber, the calibration factor of absorbed dose to water given by NIM was described in detail. According to the difference of correction items between calibrating ionization chamber and medical accelerator, the correction items were analyzed. The uncertainty of calibration chamber in 60Co radiation field is 0.71%, and the uncertainty of absorbed dose to water of high-energy photons in accelerator is 1.30%. Finally, the suggestions and precautions for calibrating absorbed dose to water of accelerator high-energy photons were given.
2019 Vol. 40 (6): 1124-1128 [Abstract] ( 338 ) HTML (1 KB)  PDF (370 KB)  ( 347 )
1129 Determination of Chlorine in Bovine Liver Reference Material
FU Chuan,SHI Nai-jie,FENG Liu-xing,CAI Ye-qiang,WANG Hai-feng
DOI: 10.3969/j.issn.1000-1158.2019.06.31
The determination of chlorine in matrix reference material is difficult. The content of chlorine in reference material of bovine liver was determined by ion chromatography combined with pyrohydrolysis and potentiometric titration following dry ashing digestion. The pretreatment and determination conditions of the two methods were optimized, the experimental results show that the results of the two methods are consistent,the relative standard deviations of the measurement results are 0.7% and 1.1% respectively. The two methods were verified by using NIST bovine liver reference material (SRM1577c), the results of the two methods are consistent with the standard values. The uncertainties of the determination results of the two methods were evaluated, and the relative expanded uncertainties of the chlorine determination results (k=2) are 1.6% and 2.2% respectively. Both methods used to determine the chlorine content in bovine liver are accurate and reliable, and can meet the requirements of reference material certification.
2019 Vol. 40 (6): 1129-1134 [Abstract] ( 312 ) HTML (1 KB)  PDF (609 KB)  ( 331 )
1135 Research on the Detection of Methane Using Hollow Photonic Band Gap Fiber
WANG Zhi-fang,WANG Shu-tao,WANG Gui-chuan,CHE Xian-ge
DOI: 10.3969/j.issn.1000-1158.2019.06.32
All-fiber methane detection system based on the spectrum absorption properties of methane using a hollow-core photonic bandgap fiber (HC-PBGF) as special gas cell was demonstrated. The detection wavelength of methane was chosen on the basis of HITRAN2012 and HAWKS; In order to accelerate methane gas diffusion, pressure difference between inlet of HC-PBGF and outlet of HC-PBGF was formed with air pump. The optical path can be extended twice by using mirrors. The results indicated that the time is 190 seconds of the gas diffusion, system value fluctuation is 0.012% in half-hour and average repetition rate is 99.63%. Finally, making up different concentration methane gases, the results indicated that methane concentration has a good linear relationship with relative strength of absorption and the linearity is 99.92%. The detection system is response speed and portable on account of the hollow-core of HC-PBGF to detect methane and make online detection more convenient.
2019 Vol. 40 (6): 1135-1139 [Abstract] ( 290 ) HTML (1 KB)  PDF (1073 KB)  ( 565 )
1140 Research on Correction Algorithm of Vehicle Gas Sensor Measurement Results
LIANG Jie,LI Qing-chao
DOI: 10.3969/j.issn.1000-1158.2019.06.33
In order to solve the problem that the measurement accuary of the vehile gas monitoring sensor is low. Forward and reverse modified algorithms were used to post-correct their measurement, thus improved the credibility of the measurement data. Through the comparison between the measurement results of the vehicle gas sensor and the fixed monitoring point analysis instrument, the two algorithms were verified, and the measurement error is reduced by 50% after the measurement result was corrected. In addition, a multilevel modified model based on these two algorithms was proposed and evaluated, and the test results of these two algorithms on the model satisfied the demand basically.
2019 Vol. 40 (6): 1140-1145 [Abstract] ( 263 ) HTML (1 KB)  PDF (1219 KB)  ( 356 )
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