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2011 Vol. 32, No. 3
Published: 2011-05-22
 
193 High/Low Voltage Power Switching Based on Dual-Loop Constant Current Control for Electromagnetic Flowmeter Excitation Control System
YANG Shuang-long,WANG Gang,XU Ke-jun,SHI Lei,LI Ji-chun
DOI: 10.3969/j.issn.1000-1158.2011.03.01
Based on the simulation analysis of constant excitation current control,a novel method of dual-loop control for constant excitation current control is proposed in order to improve high-frequency square wave excitation performance of the electromagnetic flowmeter. This method includes an outer loop for high/low voltage power switching and an inner loop for current fine-tuning,which can ensure zero satiability of the sensor output signal and high power efficiency of the excitation system when electromagnetic flowmeter is excited by high-frequency square wave. A square wave excitation control system is designed to realize to excite the coil by high frequency precisely. The simulation results show that the higher the high voltage power,the more widely the excitation frequency can be expanded. The experimental results show that the speed of constant excitation current control is fast and the sensor output signal of the electromagnetic flowmeter has steady zero when the excitation system is excited by high-frequency square wave.
2011 Vol. 32 (3): 193-197 [Abstract] ( 546 ) HTML (1 KB)  PDF (379 KB)  ( 644 )
198 Theoretical Analysis of Integration Error of Ultrasonic Flowmeter in the Disturbed Flow Condition
HU He-ming,MENG Tao,WANG Chi
DOI: 10.3969/j.issn.1000-1158.2011.03.02
The integration error of the ultrasonic flowmeter is calculated in some theoretical disturbed flow profiles. The influence of the flow structure is analyzed, and its statistical regularity to the path number is studied. The results show that the integration error is directly related to the complexity of the flow profiles. It is believed from statistical analysis that the integration error decreases successively with the number of paths increasing, but not true for the certain flow profiles. The OWICS scheme has better accuracy than the Gauss-Jaccobi scheme, especially when the number of paths is limited.
2011 Vol. 32 (3): 198-202 [Abstract] ( 598 ) HTML (1 KB)  PDF (470 KB)  ( 596 )
203 Frequency Response on the Characteristics ofthe Electrostatic Sensor Array
GAO He-ming,XU Chuan-long,FU Fei-fei,HAO Jian-xin,WANG Shi-min
DOI: 10.3969/j.issn.1000-1158.2011.03.03
The frequency characteristic of electrostatic sensor array for measurement of gas-solid two-phase flow is investigated. Mathematical model of the electrostatic sensor array is established, the dynamic sensitivity is defined. The axial sensitive zone and frequency response on the electrostatic sensor array are acquired through simulation and tests. The results show that the axial sensing zone near the electrode is smaller than that in the central axis; The frequency bandwidth near the electrode is wider and the peak values is bigger; the faster the velocity is,the wider the bandwidth is, and the peak value is bigger; the longer the electrode length is, the narrower the frequency bandwidth is. And the relationship among particle velocity, length of sensitivity zone and frequency peak value is demonstrated.
2011 Vol. 32 (3): 203-208 [Abstract] ( 553 ) HTML (1 KB)  PDF (2085 KB)  ( 526 )
209 Study on the Flowrate Mesurement in Microtubes by Micro-PIV
ZHANG Yong-sheng,LIU Yan-jun,WANG Jin-hua
DOI: 10.3969/j.issn.1000-1158.2011.03.04
In order to solve the problem of measuring the flow rate in microtubes（the hydraulic diameter is under 1mm）,the Micro-PIV is used to measure the flowrate within the capillary tube,and its hydraulic diameter is 230μm. In the experiment,the flowrate is measured in the reynolds number range of 480~2260,and the conclusion is that Micro-PIV technique can be used to measure the flowrate in the microtubes with high precision.
2011 Vol. 32 (3): 209-212 [Abstract] ( 569 ) HTML (1 KB)  PDF (424 KB)  ( 495 )
213 The Critical Flow Nozzles Flying Test MethodBased on the Principle of Mass Conservation
SHEN Wen-xin,ZHAN Zhi-jie,JIN Lan,MA Xiao-ping
DOI: 10.3969/j.issn.1000-1158.2011.03.05
In view of the shortcomings existed in the low reynolds number critical flow nozzles such as the difficulties of geometric measurement in small throat radius and the test of back pressure ratio on existing PVTt standard facility, an the active piston flow comparator is developed. According to the principle of mass conservation, a flying test method based on PcTt is presented. Test results show that the flying test method is accurate and feasible. The repeatability of discharge coefficient Cd is up to (0.02～0.05)%.
2011 Vol. 32 (3): 213-216 [Abstract] ( 500 ) HTML (1 KB)  PDF (318 KB)  ( 596 )
217 Study on Algorithms of PCB Conductor Top and Bottom Line Widths Measurement
HUANG Yong-lin,YE Yu-tang,CHEN Zhen-long,QIAO Nao-sheng
DOI: 10.3969/j.issn.1000-1158.2011.03.06
In order to measure the top and bottom conductor line widths, a fast and accurate edge extraction method is proposed. Common methods of image denoising often lead to blurred edges, especially for heavy-noise contaminated microscopic images. Firstly, P-M model is used to remove noise. This technique can preserves or even enhance prominent edges when removing noise. Canny operator is used to detect the edge in the denoised image. At last, Hough transform is used to detect lines. Experimental results show that the proposed method has strong antinoise capability. The accuracy of line widths measurement is improved. It can be applied to practical engineering measurement system.
2011 Vol. 32 (3): 217-220 [Abstract] ( 546 ) HTML (1 KB)  PDF (1899 KB)  ( 1042 )
221 The Design of Geometrical Parameters Measurement System
WANG Hong-tao,HE Xiao-bo,CHEN Qi
DOI: 10.3969/j.issn.1000-1158.2011.03.07
A novel system for measuring geometrical parameters of the measured object is designed by using machine vision and numerical control technology. In the system, the step motor is used to drive the two dimensional measuring table, the CCD camera and two grating rulers is used to acquire the outline coordinate data of the measured object, and a automatic contour tracking algorithm is executed in order to collect the complete data. The program for measuring and evaluating the straightness, roundness, parallelism and verticality is developed, as a result, the measurement of the geometrical parameters of the measured object is accomplished. The experiment results show that the designed system has high automation level, and its measuring accuracy reaches the micron degree.
2011 Vol. 32 (3): 221-226 [Abstract] ( 474 ) HTML (1 KB)  PDF (1079 KB)  ( 936 )
227 Evaluation and Identification of the Profile Errors of Complicated Plane Curve
LIN Xiao-jun,WANG Zeng-qiang,SHI Yao-yao
DOI: 10.3969/j.issn.1000-1158.2011.03.08
The method for measuring curve profile error and principle of profile error evaluation are summarized. The geometry rule of the least condition principle for evaluating profile error of the plane curve is proposed. An efficient model and algorithm are presented for planar free-form curve profile error evaluation.The self adaptive coordination is realized between the theoretical curve and the measured subject by the process of pre-positioning rough match of the feature points and fine match. At last an example has validated the correctness of the geometry rule and feasibility of this algorithm.
2011 Vol. 32 (3): 227-234 [Abstract] ( 544 ) HTML (1 KB)  PDF (1427 KB)  ( 939 )
235 A New Method for Accurate Evaluation Plane Straightness Error
YUAN Jiang,CAO Jin-Wei,QIU Zi-xue,SHAO Jian-xin
DOI: 10.3969/j.issn.1000-1158.2011.03.09
A new fast and accurate algorithm which called intercept of convex polygon method is proposed. It meets the principle of the minimum zone tolerance and can solve the problems of the traditional method such as high algorithm complexity, the evaluating precision is lower and cant appropriate for various instruments in evaluating straightness error. The algorithm is based on the convex-hull theory in computational geometry, the measurement data of different types measuring instruments are firstly converted into coordinate values, then all the measured points are divided into two group points by connecting the head point and the end point, and the convex polygons can be constructed by slope factor. The three unique points meet the least condition can be found and the plane straightness error can be calculated by shift conversion. Experimental results show that the algorithm is simple and facility for automatic data processing, and has the features of high precision and speed.
2011 Vol. 32 (3): 235-238 [Abstract] ( 596 ) HTML (1 KB)  PDF (966 KB)  ( 917 )
239 Study on the Method for Finding Optimum Working Range of Electric Eddy Sensor
MIAO En-ming,WANG Xin,YAN Yan,YANG Rui-chang,FEI Ye-tai
DOI: 10.3969/j.issn.1000-1158.2011.03.10
Electric eddy sensor is widely used in industry because of its non-contact measurement and strong anti-interference.However,its accuracy is difficult to reach the level of a few micron.Interval optimization judgment principles is proposed on the bases of the accuracy analysis theory and the error correction technology,including “minimum interval number” principle and “maximum interval ranges” principle,to determine the optimal working ranges of electric eddy sensor and improve the sensor measurement accuracy. The above principles is applied to the commercial electric eddy sensor to obtain the precision promotion,the result shows that the original accuracy of ±10μm error is improved to ±4μm error in the best working range of eddy current sensor.
2011 Vol. 32 (3): 239-243 [Abstract] ( 528 ) HTML (1 KB)  PDF (591 KB)  ( 429 )
244 Study on the Long Term Stability on the Superfluid Transition Temperature of Helium
LIN Peng,YU Li-hong,ZHANG Zhe
DOI: 10.3969/j.issn.1000-1158.2011.03.11
The long term stability of the superfluid transition temperature of helium has been studied in the past ten years using six cells sealed in 2000. The measurements are made in four laboratories with a regular procedure. A rhodium-iron resistance thermometer with series number of 229841 is used at forty-three measurements to realize the superfluid transition temperature of helium with the standard deviation of 0.035 mK.
2011 Vol. 32 (3): 244-248 [Abstract] ( 535 ) HTML (1 KB)  PDF (389 KB)  ( 418 )
249 The Calibration Method of the High-precision Thermometer for Seafloor Heat Flow Measurements
ZHOU Hang-xia,YU Ke-guang,XU Xing
DOI: 10.3969/j.issn.1000-1158.2011.03.12
According to the changes in temperature and other parameters in the marine environment, combined with the characteristic of measuring temperature of the seafloor heat flow,the influence factors on the accuracy of seafloor thermometer and its calibration method are studied.According to the laboratory calibration data of the conductivity, temperature and depth instrument to amend the zero and temperature drift of the thermometer, and compared with the data in situ testing of the seafloor thermometer, marine experimental results show that the measurement error could be maintained at less than ±0.002℃ in the range of -2℃ to +32℃ by this method.
2011 Vol. 32 (3): 249-252 [Abstract] ( 596 ) HTML (1 KB)  PDF (779 KB)  ( 745 )
253 Application of the Quartz-flexure Accelerometer to the Development of Ultra-low Frequency Vibration National Primary Standard Device
YU Mei,LIU Ai-dong,HE Wen,YANG Li-feng,HU Hong-bo,ZUO Ai-bin,MA Ming-de
DOI: 10.3969/j.issn.1000-1158.2011.03.13
The improved quartz-flexure accelerometer with independent developed condition-amplifier is adopted as the vibration pickup sensor in ultra-low frequency vibration feedback control, and as the standard implement for performance measuring of ultra-low frequency vibration primary standard device. The distortion of vibrator output acceleration waveform is decreased effectively, and the effect of environmental vibration is suppressed to some extent. The acceleration distortion is less than 1% above 0.002 Hz.It solves the measurement means problem caused by without measuring sensor below 1Hz.The stability and repeatability meet requirements of standard devices.It is considered that it can be used as the standard implement of calibration and the check standard for low frequency or ultra-low frequency vibration national primary standard and standard devices.
2011 Vol. 32 (3): 253-257 [Abstract] ( 825 ) HTML (1 KB)  PDF (458 KB)  ( 830 )
258 Study on Static Balance Measurement of Gyroscope
LIU Guo-dong,LIU Bing-guo,LI Jia,ZHU Xiao-fang,ZHANG Zhuo
DOI: 10.3969/j.issn.1000-1158.2011.03.14
A novel design of the rotor static balance measuring instrument structure is introduced, in which an agate blade bearing and autocollimator are adopted, and high accuracy measurement for rotor static balance is realized. A novel mechanism combining coarse fine double blades bearing ensures high precision and wide range, reduces the wear and tear of blades, and improves the efficiency of measurement. The sensitivity coefficient of the instrument is adjusted by measuring the swing period of rotor bearer. The instrument is calibrated by standard weights, experiment results show that the precision of the instrument is about 4mg·mm and the measurement range is about 2000 mg·mm.
2011 Vol. 32 (3): 258-261 [Abstract] ( 542 ) HTML (1 KB)  PDF (449 KB)  ( 688 )
262 Study on 3D Laser Scanning Method for Horizontal Tank Volume Measurement
WANG Jin-tao,LIU Zi-yong,ZHANG Long,GUO Li-gong,BAO Xue-song,TONG Lin
DOI: 10.3969/j.issn.1000-1158.2011.03.15
Based on 3D laser scanning principle, one automated measuring method used for horizontal tank volume measurement was proposed, which was compatible with the technical regulations of OIML R80, API STD2551 and JJG 266—1996. Point cloud of the tank scanned data was analyzed, and one area computation algorithm for section with equal liquid lever was introduced based on triangle superimposition method, then the tank volume below this liquid lever was calculated. The comparison experimental system was designed, and the measurement result from the volumetric method was regarded as reference. The measuring relative error of 3D laser scanning method was less than that of geometric measuring method, and meet the metrology uncertainty requirement of 0.4% (k=2), which verified the measuring method discussed. On the other hand, the calibration efficiency for the horizontal tank would be improved significantly by this 3D laser scanning method.
2011 Vol. 32 (3): 262-265 [Abstract] ( 628 ) HTML (1 KB)  PDF (507 KB)  ( 450 )
266 ABS Wheel Speed Signal Processing Based on Kalman Filter
SUN Jun,YIN An-dong,JIANG Wei-long,WANG Peng-lu
DOI: 10.3969/j.issn.1000-1158.2011.03.16
The measured vehicle wheel speed signal is processed respectively by Kalman filter and tradition filter method.The analysis indicates that the wheel angle acceleration signal processed by Kalman filter can show the operation process of ABS system more really than traditional filter, and proves that the Kalman filtering is an effective means to wheel speed signal processing of ABS system. So that the control algorithm of ABS system with Kalman filter can prevent the wheel lock during braking and improve the direction stability of vehicle brake more effectively.
2011 Vol. 32 (3): 266-268 [Abstract] ( 478 ) HTML (1 KB)  PDF (789 KB)  ( 393 )
269 Study on the Technology of Large-scale High SpeedParallel Sampling and Calibration
ZENG Hao,WANG Hou-jun,YE Peng,PAN Hui-qing,XIANG Chuan-yun
DOI: 10.3969/j.issn.1000-1158.2011.03.17
The structure with multi-ADC parallel sampling can rapidly increase the real-time sample rate of high speed data acquisition system.The whole diagram of a large-scale parallel sampling system is introduced. The technology of the generation of high speed parallel clock network, trigger point location and the real-time calibration of the non-uniform sampling are discussed. The experiment results are presented and analyzed. This high speed data acquiring system has the merits of low-cost, reliable performance and real-time.
2011 Vol. 32 (3): 269-274 [Abstract] ( 514 ) HTML (1 KB)  PDF (1952 KB)  ( 847 )
275 A New Real-valued Negaletive Selective Algorithm Based on Hypersphere as Antibody Recognition Zone
LIU Ying,XIONG Ping
DOI: 10.3969/j.issn.1000-1158.2011.03.18
In the view of geometry model, the function of artificial immune is to divide the space into areas. Hypersphere is regarded as an antibody recognition zone of artificial immune system. The shortage of the traditional negative selection algorithm is discussed, and an improved algorithm is presented. Simulation and experimental results indicate that the proposed method is feasible.
2011 Vol. 32 (3): 275-278 [Abstract] ( 437 ) HTML (1 KB)  PDF (548 KB)  ( 491 )
279 A New Method for Cycle-Slip Detection and Correction in GPS Carrier Phase
TENG Yun-long,SHI Yi-bing,GUO Cheng-jun
DOI: 10.3969/j.issn.1000-1158.2011.03.19
Based on the characteristics of cycle-slip, it is regarded as the fault of GPS carrier phase observations, and then how to detect it is considered as the problem of fault feature extraction. According to these analyses, a new algorithm for detecting and correcting cycle-slip is presented. The fourth difference series of carrier phase observations are calculated. Then, the Huang-Hilbert transform is carried out to the difference series, and the location of cycle-slip can be detected by ascertaining the point of modulus maximal value of the high frequency coefficients. Finally, the forecasted model of carrier phase observations on the basis of RBF neural network is established. The number of cycle-slip can be determined by comparing the difference between the forecasted and actual values. Experimental results are presented to demonstrate the feasibility and validity of the method.
2011 Vol. 32 (3): 279-284 [Abstract] ( 508 ) HTML (1 KB)  PDF (1028 KB)  ( 557 )
285 Application of Graphene in Metrology
ZHONG Yuan,HE Qing
DOI: 10.3969/j.issn.1000-1158.2011.03.20
Graphene is a novel material with a number of unique properties, which is a single layer of carbon packed in a hexagonal lattice. Graphene exhibits relativistic Dirac electrons properties for the electronic structure, and that is different from usual three-dimensional materials. Graphene is the most ideal two-dimensional electron gas system in all available materials, which makes it interesting for both fundamental studies and future applications. The structure, properties, preparation methods and future applications of graphene are reviewed, and the potential applications in metrology are discussed.
2011 Vol. 32 (3): 285-288 [Abstract] ( 595 ) HTML (1 KB)  PDF (992 KB)  ( 867 )
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