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2018 Vol. 39, No. 2
Published: 2018-03-22
 
145 Measurement Research on Mass Property Parameters of Unmanned Aerial Vehicle
WEN Jing-jing,DENG Dan,WU Bin
DOI: 10.3969/j.issn.1000-1158.2018.02.01
Based on three-point weighing method and torsion pendulum method,a mass property measurement system which is adapted to the Unmanned Aerial Vehicle with quality of 200～1 000 kg,the total length less than 4 m,and the wingspan of no more than 2 m is designed. This system is able to measure all the quality characteristic parameters by one time, is easy to make and use. Compared with the traditional vertical installation method, small flip angle measurement is presented, which can not only improve the measurement accuracy, but also ensure the safety of the product measurement. The actual sample measurement results show that measurement time reduced by 60%, the relative errors of the measured mass centroid are all less than 1%, the relative errors of the measured moment of inertia and product of inertia are all less than 4%.
2018 Vol. 39 (2): 145-150 [Abstract] ( 528 ) HTML (1 KB)  PDF (803 KB)  ( 710 )
151 Study on the Influence of Air Buoyancy for the Dissemination Based on Mass Primary Standard
HAN Zhi,WANG Jian,LUO Zai
DOI: 10.3969/j.issn.1000-1158.2018.02.02
The CIPM-1981 formula, the CIPM-81/91 formula and the CIPM-2007 formula are used to calculate the air buoyancy correction during the dissemination of mass primary standard respectively, there are some differences among these results. In order to analyze the influence of three formulas on the air buoyancy correction, the calculation results of air buoyancy correction is compared under different conditions. The results show that the maximum difference is 42μg under different environmental conditions, when the volumes of national kilogram primary standard No. 60 and national kilogram secondary standard No. 121 have known.
2018 Vol. 39 (2): 151-154 [Abstract] ( 520 ) HTML (1 KB)  PDF (291 KB)  ( 389 )
155 Research on High Accuracy Torque Standard Machine
ZHANG Zhi-min,LI Tao,ZHANG Yue,MENG Feng,JI Hong-lei,ZHANG Wei,HU Gang
DOI: 10.3969/j.issn.1000-1158.2018.02.03
A set of high accuracy 1mN·m～1N·m torque standard machine was newly developed at National Institute of Metrology (NIM). A static air bearing is used to support an arm lever at a fulcrum, a single beam structure is adopted in the arm lever which is equipped with a balancing beam and a overload protection part, an unique weight loading system is designed and manufactured by using precise combination of load frame, groups of weights and weight supporting part. The working principle and mechanical structure of the machine are introduced, the results of performance test and uncertainty assessment are described. The theoretical analysis and performance tests show the expanded uncertainty(k=2) of the machine is less than 3.4×10-4 from 1mN·m to 5mN·m, 7.4×10-5 from 5mN·m to 100mN·m, 2.6×10-5 from 100mN·m to 1N·m.
2018 Vol. 39 (2): 155-158 [Abstract] ( 498 ) HTML (1 KB)  PDF (840 KB)  ( 283 )
159 A Torsion Balance Device for Measuring the Gravity Gradient
YU Ye,HU Xiang,XIONG Chao,SHI Wen-jing,TU Liang-cheng
DOI: 10.3969/j.issn.1000-1158.2018.02.04
Based on the principle of torsion balance measuring gravity gradient , a torsion balance gravity gradiometer was designed, which consists of a torsion balance system, an angle measurement system, an amplitude attenuation system, a turntable system, a vacuum container system. Considering the stable time of torsion balance suspension system was too long, which had great impacted the efficiency of the gravity gradient measurement, an amplitude attenuation system was designed in combination with PID control technology.Simulation results show that, the curvature and horizontal gravity gradient could be measured, the accuracy was as high as 0.5 E(1E=1×10-9m/s2), and the limit efficiency of measuring a group of gravity gradients was better than an hour.
2018 Vol. 39 (2): 159-162 [Abstract] ( 418 ) HTML (1 KB)  PDF (435 KB)  ( 271 )
163 Research on Hardware-in-the-Loop Test of Bus Antilock Brake System Based on Fuzzy PID
LU Yi,XU Bo-wen,WU Jia-wei,GUO Bin
DOI: 10.3969/j.issn.1000-1158.2018.02.05
Due to hardware-In-the-loop test method , the hardware-In-the-loop test system of bus antilock brake system was built. The system consists of three parts: Matlab/xPC target real-time environment, pneumatic brake system and vehicle dynamics model. The data of the braking force of the bus can be collected to calculate results and display. For vehicle braking parameter self-tuning fuzzy PID control algorithm was introduced in the control strategy of ABS. The braking condition of the bus in large and small adhesion coefficient road, bisectional road and joint road was tested. Test results show that the method can be used for real-time tuning of the PID parameters according to the braking condition, and the wheel slip rate stay stably in the vicinity of the best slip rate 0.2(large adhesion coefficient road)and 0.1(small adhesion coefficient road), which has good adaptability and control precision.
2018 Vol. 39 (2): 163-167 [Abstract] ( 707 ) HTML (1 KB)  PDF (391 KB)  ( 407 )
168 Strain Measurement and Optimal Placement of Fiber Bragg Sensors in Adhesive Layer of Composites
ZHANG Yu-yan,REN Tian-xin,WEN Yin-tang,LIU Yong,Liu Ze-liang
DOI: 10.3969/j.issn.1000-1158.2018.02.06
The composite materials for aeronautical application are usually assembled on the substrate surface by means of adhesion agent. It is inevitably to create a variety of defects and damage in the bonding and service process. The interface bonding quality has great influence on material’s preservation performance. In order to evaluate defect and damage in the adhesive layer, a method of optimal placement of fiber Bragg grating (FBG) sensor networks for strain monitoring of composite adhesive layer structures is proposed. Based on the principle of FBG strain sensing, Bragg wavelength shift law of FBG sensor under static loads is studied by simulations and experiments. According to the experimental results, the detection model which matches the actual characteristics of FBG sensor is established. On this basis, the particle swarm optimization algorithm that implements optimal arrangement of FBG sensing network is applied. Experimental show that sensor coverage has improved significantly as the position coordinates of FBG sensor is optimized.
2018 Vol. 39 (2): 168-172 [Abstract] ( 454 ) HTML (1 KB)  PDF (885 KB)  ( 545 )
173 A Excogitation of Function Configurable Manipulator Based on the Intelligent Cylinder
JIANG Ning,YAO En-tao,ZOU Hua-zhang,JIA Shang-yuan
DOI: 10.3969/j.issn.1000-1158.2018.02.07
The working principle and excogitation method of a function configurable manipulator based on Intelligent cylinder is introduced. Intelligent cylinder is an intelligent unit with integrating SCM,sensors and electric-magnetic valve into cylinder. It has been done that establishing mathematical model of the cylinder action for simulation, designing a configured method for requirement of fast and flexible configuration which can make all kinds of functions of intelligent cylinder configuring rapidly to the required function of manipulator. Experiments show that this design method can realize the basic function of the manipulator, and the excogitation method provides a new solution for the multi-function, low-cost and flexibility of the manipulator.
2018 Vol. 39 (2): 173-177 [Abstract] ( 431 ) HTML (1 KB)  PDF (904 KB)  ( 712 )
178 Study on A Novel Calibration Method for Vibration Torque Sensor
ZHAO Hao,FENG Hao
DOI: 10.3969/j.issn.1000-1158.2018.02.08
A novel calibration method for vibration torque sensor is presented. The calibration system includes vibration torque excitation source,vibration torque sensor and adjusting load, which are connected coaxially in operating. The electromagnetic torque of vibration torque excitation source generates constant component and vibration component, of which both amplitudes are the same. Therefore, the value of load and the amplitude of vibration torque are same when the calibration system is in steady operation according to the torque balance equation. The vibration torque sensor can be calibrated by recording the load value. The vibration torque sensor was calibrated by experiment, and the corresponding performance indicators are received, which verified the feasibility of the calibration method.
2018 Vol. 39 (2): 178-181 [Abstract] ( 455 ) HTML (1 KB)  PDF (327 KB)  ( 263 )
182 Tool Wear State Monitoring Based on Variational Mode Decomposition and Correlation Dimension and Relevance Vector Machine
HE Zhi-jian,ZHOU Zhi-xiong,HUANG Xiang-ming
DOI: 10.3969/j.issn.1000-1158.2018.02.09
According to unstable-state and non-linear characteristics of tool wear signal, a recognition method based on variational mode decomposition correlation dimension and relevance vector machine is proposed. First, the acoustic emission signal was decomposed by variational mode decomposition, then a series of components were obtained. The components generated by variational mode decomposition have different sensitivity to condition of tool wear. According to the mutual information of components, sensitive components were selected, which were used to calculate the correlation dimension of sensitive components and combined into a feature vector. Finally, the feature vector were input relevance vector machine, which will be classified, trained and tested, in order to identify the state of tool wear. By comparing classification accurate rate of variational mode decomposition and applied empirical model decomposition methods, the superiority of the proposed method based on variational mode decomposition is demonstrated in state recognition of tool wear.
2018 Vol. 39 (2): 182-186 [Abstract] ( 395 ) HTML (1 KB)  PDF (959 KB)  ( 372 )
187 Research on the P-S-N Curve of Fatigue Life of Automatic Brake Adjuster Based on Three Parameter Weibull Distribution
LUO Zai,WANG Lan-jing,TANG Ying-qi,TIAN Kun
DOI: 10.3969/j.issn.1000-1158.2018.02.10
An experimental study on the fatigue properties of automatic brake adjuster is presented. The deflection ability,failure characteristics and fatigue life were investigated．It is observed when fatigue stress is applied,middle stress concentration parts of the rectangular compression spring will produce crack. While stress level increases,the crack becomes bigger,which makes its ability to transfer torque reduced. Using the method of least squares and maximum correlation coefficient fitting of the fatigue life of automatic brake adjuster,it was shown that its fatigue life obey the three parameter of Weibull distribution. According to the three parameters in the form of power function S-N curve equation, the automatic brake adjuster under different stress P-S-N curve is setd up. The automatic brake adjuster test was compared with the theoretical fatigue limit life which shown the relative error of the two is small.
2018 Vol. 39 (2): 187-191 [Abstract] ( 430 ) HTML (1 KB)  PDF (1190 KB)  ( 303 )
192 Study on the Influence of Ambient Pressure on Liquid Density Transmission
ZHANG Jing-yue,WANG Jin-tao,SHI Wen-cai,LIU Xiang,LI Zhan-hong,TONG Lin1,MA Xin-yu
DOI: 10.3969/j.issn.1000-1158.2018.02.11
As an important part of density standards, liquid density standard plays a significant role in quantity transfer and traceability. In order to correct the influence of pressure, a method is proposed to measure the compressibilities of density standard liquids at low pressure. The relationship between the density of liquid and pressure is established by a calibration measuring which device of pure water and air standard density. Compressibilities of density standard liquids were measured by vibrating-tube densimeter calibrated. According to the result, the relative change is about 1×10-6 in the density of the liquid caused by the elevation of 100 m, which verified the necessity of the correction.
2018 Vol. 39 (2): 192-196 [Abstract] ( 470 ) HTML (1 KB)  PDF (397 KB)  ( 320 )
197 Study on the Measurement of Liquid Density bySupporting Resonance Method
HAN Li-li,CAO Xu,WANG Qian,WANG Jie,QI Kai,LI Shu-guang
DOI: 10.3969/j.issn.1000-1158.2018.02.12
Experimental support resonance method is used to measure Young's modulus experiment device, and material separation variable method is used to approximate solution Housner transverse vibration equation of tubular material containing fluid tube material which can obtain the liquid density calculation formula. Through the experimental measurement and calculation of the density of distilled water and different concentrations of sucrose solution values, the relative error between the experimental value with the theoretical value is in the normal range of error of being less than 3%,which provides a new method to measure the liquid density.
2018 Vol. 39 (2): 197-200 [Abstract] ( 430 ) HTML (1 KB)  PDF (411 KB)  ( 480 )
201 Research on the Method of the Triaxial Primary Vibration Calibration Using the Heterodyne Interferometry
YANG Ming,CAI Chen-guang,LIU Zhi-hua,WANG Ying
DOI: 10.3969/j.issn.1000-1158.2018.02.13
Compared with the one-axial vibration excitation in the traditional calibration method, the triaxial standard vibration exciter can simulate the actual application environment of the calibrated accelerometer. The spatial response characteristic of the accelerometer can be obtained by using the triaxial standard vibration exciter to realize the accurate calibration of the accelerometer. The sensitivity matrix model of the triaxial accelerometer was proposed which used the bandpass based on heterodyne interferometry triaxial primary vibration calibration method and the theory of the acceleration vector. This method realizes the calibration of the accelerometer by calculating its sensitivity matrix. The experimental results show that this method can simultaneously realize the high precise calibration of the principal and the transverse sensitivities of the triaxial accelerometer, and this method can effectively reduce the calibration time and the error caused by the repetitive installations.
2018 Vol. 39 (2): 201-206 [Abstract] ( 464 ) HTML (1 KB)  PDF (1250 KB)  ( 607 )
207 Fixed Standard Instrument for Field Tests of Vehicle Speed Measuring Devices Based on Actual Traffic
DU Lei,SUN Qiao,LIN Feng,BAI Jie,WANG Xiao-lei,YE Zhen-zhou
DOI: 10.3969/j.issn.1000-1158.2018.02.14
To meet the requirement of new field testing method of vehicle speed measuring devices, a fixed standard instrument for field tests of vehicle speed measuring devices used in actual traffic is developed. The design idea and scheme of the standard instrument are introduced. The working principle of the standard speed meter used in the standard instrument is analyzed, and the speed measurement uncertainty of the standard speed meter is evaluated. The uncertainty evaluation results show that the relative expanded uncertainty is 0.12% (k=3) in the speed measurement range of 20~250km/h. The feasibility of new field testing method of vehicle speed measuring devices and the actual speed measuring performance of the standard instrument in actual traffic are verified by the large samples field testing data of 2 kinds of vehicle radar speed measuring devices.
2018 Vol. 39 (2): 207-212 [Abstract] ( 449 ) HTML (1 KB)  PDF (1220 KB)  ( 274 )
213 Research on High Rotational Speed Standard Device
SUN Qiao,BAI Jie,DU Lei,FAN Zhe,HU Hong-bo
DOI: 10.3969/j.issn.1000-1158.2018.02.15
The high rotational speed standard device based on brushless DC coreless micro motor and FPGA technology for high-accuracy rotational speed control was investigated and established,with resolution of 1 r/min in the measurement range of 30 000 r/min to 100 000 r/min. The expanded calibration uncertainty of this standard device is 1×10-5, k=3. The structure of the device and key technology involved were described． The dual closed-loop control solution was explained.The calibration results were provided． This high rotational speed standard device is used as an important working standard for the feasible traceability of high-precision optical tachometers and rotational speed measuring instruments at measurement range above 30 000 r/min.
2018 Vol. 39 (2): 213-216 [Abstract] ( 488 ) HTML (1 KB)  PDF (546 KB)  ( 583 )
217 Method of Deformation Measurement for Vertical Tank Based on 3D Laser Scanning Method for Production Safety Oil Depot
WANG Jin-tao,LIU Xiang,TONG Lin,LIU Zi-yong,BAO Xue-song
DOI: 10.3969/j.issn.1000-1158.2018.02.16
In view of the quality and improper operation of the vertical tank, the deformation of the vertical metal storage tank will affect the normal operation and safe operation of the tank and the accuracy of volume measurement. Application of 3D modeling technology of laser scanning, a new method for deformation measurement of large vertical metal tank analysis based on point cloud data is studied and calculated by the iterative algorithm of geometry radius of each plate. High accuracy of the vertical tank plate model was obtained using the geometric radius calculated. The wall deformation measurement platform is used to measure the deformation parameters of the local area, and the synchronous measurement of the whole and local deformation of the vertical tank plate is realized. A 10104m3 vertical floating roof tank (diameter 79.937m) is used as the experimental study, which verified the effectiveness of this method.
2018 Vol. 39 (2): 217-221 [Abstract] ( 433 ) HTML (1 KB)  PDF (712 KB)  ( 338 )
222 Volume Measurement Method of Vertical Metal Tank Based on Laser Scanning
HAO Hua-dong,LI Cun-jun,LIU Ying,SHI Hao-lei,LI Shu-guang
DOI: 10.3969/j.issn.1000-1158.2018.02.17
According to the traditional large capacity measurement methods have some shortcomings, such as low accuracy, low work efficiency and labor intensity, a volume measurement method for vertical metal tank based on laser scanning is presented. The volume calculation model is established for vertical tank and the concrete implementation process is analyzed. And the key algorithms are researched for the laser point cloud data analysis and process. The volume value is automatically calculated in the different liquids by calculating the cross-sectional area along the horizontal direction of tank and integrating from vertical direction. A vertical tank is selected as the measurement object, which has the nominal capacity of 1000 m3. It is shown the good repeatability and reappearance of the proposed method. To design an experimental comparison system, the measurement experiment is carried out in three different vertical tanks which has the nominal capacity of 1000 m3, 2500 m3 and 5000 m3, respectively. The maximum relative deviation of volume measurement between the proposed method and total station method is 0.0729%, 0.0329% and 0.0582%, respectively.
2018 Vol. 39 (2): 222-227 [Abstract] ( 426 ) HTML (1 KB)  PDF (400 KB)  ( 256 )
228 Research on Measurement Method of Spherical tank Capacity Based on Laser External Scanning
CHEN Xian-lei,HAO Hua-dong,SHI Hao-lei,LI Shu-guang
DOI: 10.3969/j.issn.1000-1158.2018.02.18
A volume measurement method for spherical tank based on laser external scanning is presented. The method is applied to scan the outside of spherical tank at multi-point station. And the point cloud data automatic splicing method is studied based on the spherical target, so the full point cloud data can be got for the outer wall of the spherical tank. Then the geometry space model of spherical tank is established, and tank volume is calculated. Through the test of a spherical tank with the capacity of 200 m3, the volume measurement relative error between the proposed method and total station method is 0.304%.
2018 Vol. 39 (2): 228-230 [Abstract] ( 422 ) HTML (1 KB)  PDF (851 KB)  ( 259 )
231 Rolling Bearing Fault Diagnosis Based on Local Mean Decomposition Multi-scale Fuzzy Entropy and Grey Similar Incidence
MENG Zong,ZHAO Dong-fang,LI Jing,XIONG Jing-ming,LIU Shuang
DOI: 10.3969/j.issn.1000-1158.2018.02.19
A rolling bearing fault diagnosis method based on local mean decomposition(LMD) of multi-scale fuzzy entropy and grey similar incidence is discussed. In this method, the fault signal is decomposed into several product functions (PF) adaptively, and the multi-scale fuzzy entropies of the PF components covering contain main fault information, which is calculated to get the fault feature vectors. By calculating the grey similar incidence of the sample to be identified and the standard fault pattern, it is realized that the judgement of rolling bearing fault types and damage degree. Compared with the method based on LMD fuzzy entropy and grey similar incidence, the experimental results show that the method based LMD multi-scale fuzzy entropy and grey similar incidence can identify rolling bearing running state efficiently and realize rolling bearing fault diagnosis.
2018 Vol. 39 (2): 231-236 [Abstract] ( 460 ) HTML (1 KB)  PDF (433 KB)  ( 273 )
237 Synchrosqueezing-cross Wavelet Transform and Enhanced Fault Diagnosis of Rolling Bearing
LI Ji-meng,HUANG Meng-jun,XIE Ping,JIANG Guo-qian,CHEN Meng,HE Qun
DOI: 10.3969/j.issn.1000-1158.2018.02.20
In order to more effectively monitor and diagnose bearing faults, an enhanced fault diagnosis method was proposed based on synchrosqueezing-cross wavelet transform(SXWT). First, this method segmented the signal into two sub-signals with the same length. Then, using the synchrosqueezing wavelet transform(SWT) deals with the two sub-signals respectively, so as to obtain synchrosqueezing wavelet transform coefficients to be used as the input of cross wavelet transform(XWT). Finally, the obtained cross wavelet scale spectrum was used to extract the characteristic frequency information, thus achieving the enhanced fault diagnosis of bearings. The method is applied to the bearing fault diagnosis. Compared with continuous wavelet transform(CWT), XWT and SWT, the proposed method can effectively extract the detail characteristics of bearing signal in the time-frequency domain to enhance the readability of the bearing characteristics frequency in the time-frequency domain, and realize accurate and reliable diagnosis of the bearings faults.
2018 Vol. 39 (2): 237-241 [Abstract] ( 516 ) HTML (1 KB)  PDF (954 KB)  ( 361 )
242 Detecting Roundness Error Based on Quantum Genetic Algorithm
SHEN Cui-xiang,ZHANG Xiao-yu
DOI: 10.3969/j.issn.1000-1158.2018.02.21
In order to improve the roundness measurement accuracy, quantum genetic algorithm was proposed. Firstly, the center coordinates and the radius of the roundness image of the modeling data were established using the least square fitting. Secondly, unacceptable roundness data were rejected in the roundness calculation. Thirdly, multi-bit coding was completed using quantum genetic algorithm, and quantum revolving gate non-fixed step size adjustment and updating were implemented. Finally, the procedure for measuring the roundness error was presented. Simulation results indicated that the proposed algorithm produces accurate measurements, and when compared with the three-coordinate measuring machine, the error is within 0.0058mm, and the relative error of radius is within -0.19%, the maximum measurement errors all being within 0.01%.Further, the maximum error fluctuation is stable, and relative to other methods, the measurement uncertainty is lower.
2018 Vol. 39 (2): 242-245 [Abstract] ( 449 ) HTML (1 KB)  PDF (848 KB)  ( 314 )
246 Research on Calibration Method Key Parameters of EL Infrared Defect Tester
ZHANG Ke-jia,ZHANG Bi-feng,XIONG Li-min,ZHOU Tao-geng,ZHANG Jun-chao,MENG Hai-feng,CAI Chuan,HE Ying-wei,LI Xiao-hui,WANG Chang-shi
DOI: 10.3969/j.issn.1000-1158.2018.02.22
Based on the spatial frequency response(SFR) test method, a calibration device for the critical parameters of the EL infrared defect tester was built.The effects of focusing and position placement on the resolution calibration are analyzed.For the portable and fixed EL tester, the corresponding test methods and operational procedures are given.A test method for portable EL tester is proposed, which can realize the calibration without reference background.Based on the above calibration device, the resolution parameters of various EL testers can be calibrated and the measurement results are reproducible.
2018 Vol. 39 (2): 246-250 [Abstract] ( 537 ) HTML (1 KB)  PDF (1031 KB)  ( 468 )
251 Infrared Image Fuzzy Enhancement of Circuit Board Based on Symmetric Butterfly Universe Algorithm
SUN Yun-juan
DOI: 10.3969/j.issn.1000-1158.2018.02.23
In order to improve the quality of infrared image fuzzy enhancement of circuit board,symmetric butterfly algorithm is proposed. Firstly, symmetric butterfly universe topology was built,whole universe information exchange was used pitch line,and symmetrical butterfly structure was segmented different sections,and the same section information exchange rate was higher than different sections.Secondly, different sections of information exchange process was given,which could communicate with other universes while the universe has information exchange.Finally, infrared image fuzzy enhancement of circuit board was adaptived with incomplete Beta function in different gray level.Simulation experiments show that the symmetric butterfly universe algorithm would make infrared image fuzzy enhancement of circuit board more clearer,and quality coefficient and background suppression factor is better than other algorithms.
2018 Vol. 39 (2): 251-254 [Abstract] ( 410 ) HTML (1 KB)  PDF (1087 KB)  ( 214 )
255 Thermodynamic Temperature Measurement Using Single Cylindrical Microwave Resonator
CUI Jin,FENG Xiao-juan,LIN Hong,ZHANG Jin-tao,HUAN Ke-wei
DOI: 10.3969/j.issn.1000-1158.2018.02.24
Using the microwave resonant method, the thermodynamic temperature is measured in the temperature range from 253 K to 303 K based on the gas refractive index primary thermometry by using the properties for argon from“ab initio”quantum mechanics calculation theory and experimental results and the microwave resonant method. Four transverse magnetic microwave resonance frequencies were measured to obtain the refractive index in argon at 700 kPa, the consistence of the refractive index from different microwave modes was better than 1×10-8. The thermodynamic temperature then was determined by combining the refractive index measurement results and the viral equation of state for argon. The uncertainty of the difference of the thermodynamic temperature T and the ITS-90 international temperature T90 was evaluated to be 11.6 mK, and the results agreed with the Consultative Committee for Thermometry (CCT) recommendation values well. The uncertainty from this method will be decreased with the development of the theoretical calculation for argon and the improvement of the pressure measurement in the next future.
2018 Vol. 39 (2): 255-261 [Abstract] ( 500 ) HTML (1 KB)  PDF (1322 KB)  ( 595 )
262 Research on Dynamic Characteristics of Closed Process for New Control and Protection Switch
SU Jin-zhou,XU Zhi-hong
DOI: 10.3969/j.issn.1000-1158.2018.02.25
Based on the structure of KB0 series products, a new dynamic test system of control and protection switch based on single-chip microcomputer and high-speed image processing technology is designed on the basis of its dynamic mathematical model. The system can test the displacement of the core and the contact of the protective switch, and verify the accuracy of the displacement test under no-load condition. The dynamic characteristics of the new control and protection switch closing process are studied. The closing action time of the switch is tested under different working voltage, working frequency and closing phase angle. It has be done that studing on the contact bounce phenomenon model control and protection switch process, analyzing the reason of a bounce and two bounce generated, and exploring its core and closed at the end of the speed inner link mechanism. The optimum phase obtained is about 30 degrees through the test results of the data statistics and chart analysis, considering the time of action, contact bounce, terminal velocity and core at the end of the contact speed parameters.
2018 Vol. 39 (2): 262-267 [Abstract] ( 399 ) HTML (1 KB)  PDF (833 KB)  ( 305 )
268 A Novel Multi-frequency Measurement Method for Large Trigger Delay of Digital Oscilloscopes
LIANG Zhi-guo,YANG Ren-fu
DOI: 10.3969/j.issn.1000-1158.2018.02.26
Aiming at the large trigger delay of digital oscilloscope, a novel multi-frequency measurement method is presented. By using the period of sinusoidal as standard, the large trigger delay is divided into two parts, one part is just consist of many periods of sine wave, another part includes the partial period of sine wave. The partial period part can be measured through phase difference method. The integer periods part can be measured by using different frequency stimulation, of which the difference of the trigger delay value at different signal frequency has the same common period, and one can judge the minimum common period from three frequency sampling series. Then, the minimum common period can be used to calculate the number of periods. Finally, through composing of the two parts, the large trigger delay is gotten. The correctness and feasibility are proved by some experiments on digital oscilloscope, and the method can be used to the measurement and calibration of large trigger delay of digital oscilloscopes.
2018 Vol. 39 (2): 268-271 [Abstract] ( 445 ) HTML (1 KB)  PDF (461 KB)  ( 340 )
272 Coplanar Waveguide Transmission Line Capacitance Measurement and Uncertainty Analysis
LUAN Peng,WANG Yi-bang,LIANG Fa-guo,YANG Bao-guo
DOI: 10.3969/j.issn.1000-1158.2018.02.27
An accurate method is used to determine the coplanar waveguide (CPW) transmission line capacitance of commercial alumina substrate 101-190C （CASCADE）, which involves the measurement of transmission lines reflect and extrapolation technique. An MCM method is used to evaluate the uncertainty of transmission line capacitance measurement, which involves calibration kit and dynamic accuracy of magnitude and phase. Finally, the transmission line capacitance is used in the multiline TRL calibration, the result is very contiguous with NIST. Compared with NIST, the results show that the error of the magnitude of reflection is within ±0.02, the error of the transmission magnitude is within ±0.05 dB, and the error of the transmission phase is within ±1° above 40 GHz.
2018 Vol. 39 (2): 272-275 [Abstract] ( 476 ) HTML (1 KB)  PDF (1044 KB)  ( 408 )
276 Motor Imagrey Brain Computer Interface Band Selection Based on Improved Differential Evolution Algorithm
HU Chun-hai,LI Tao,LIU Yong-hong,QI Fan
DOI: 10.3969/j.issn.1000-1158.2018.02.28
Due to the fact that different peoples brain response to events is in different frequency bands, a method of multi-strategy mutation operator and time-varying nonlinear crossover factor differential evolution is proposed for accurate determination of the personal optimal filtering frequency band, and feature vectors are extracted by common spatial pattern algorithm and classified by the linear classifier. Based on this strategy, 10 times 5-fold cross validation experiments for BCI competition III-dataset 4a EEG data of five subjects are implemented. Experimental results show that the algorithm has the advantages of strong stability, less time-consuming and strong real-time performance, and the problem of optimal bands selection in motor imagery BCI feature extraction is therefore solved.
2018 Vol. 39 (2): 276-279 [Abstract] ( 436 ) HTML (1 KB)  PDF (523 KB)  ( 556 )
280 Uncertainty Evaluation on the Calorific Value of Natural Gas by GC
YAN Wen-can,WANG Chi,PEI Quan-bin,WANG Hai-feng,LI Chun-hui,SHEN Chao
DOI: 10.3969/j.issn.1000-1158.2018.02.29
According to the current status and requirements of energy determination of natural gas, the measuring method of the calorific value of natural gas was investigated. The gas chromatograph (GC) was used to measure high calorific value. The GC was calibrated with standard gas with different calorific value in order to verify the consistent of the standard gas and the measurement accuracy of GC. The uncertainty evaluation method of the natural gas calorific value was presented. The results of the analysis showed that the relative expanded uncertainty of measurement results from on line GC could be within 0.15%～0.30%.
2018 Vol. 39 (2): 280-284 [Abstract] ( 664 ) HTML (1 KB)  PDF (306 KB)  ( 819 )
285 The Cognition of Measurement Error and Classification from the Perspective of “Stochastic Process”
LI Bing-ying,LI Yong-xin,MA Yu-ming,GE Fang-li
DOI: 10.3969/j.issn.1000-1158.2018.02.30
To points out that the measurement error has statistical characteristic when as a “stochastic process”, it has been done that to analyze the error component’s characteristic caused by different factor in “stochastic process” with the characteristic parameters such as self-correlation function and power spectrum density, and to come to the conclusion that the systematic error and random error in classical error theory should be the practical classification of this “stochastic process”. The essences of systematic error and random error are two limit cases of “self-correlation”. The systematic error is a completely positive correlation with the self-correlation coefficient equal to 1, and the random error is a completely none correlation with the self-correlation coefficient equal to 0. 　　
2018 Vol. 39 (2): 285-288 [Abstract] ( 478 ) HTML (1 KB)  PDF (505 KB)  ( 566 )
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