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2024 Vol. 45, No. 12 Published: 2024-12-28

	1745	Study on Fiber Length Standard Device and Results Correction

		In order to meet the domestic length metrological requirements of optical time-domain reflectometer (OTDR), a new generation of fiber length standard by National Institute of Metrology based on the principle of the modulation phase shift technique is realized, which adopts a modular design, including the main system units such as the laser driver, signal modulation, photoelectronic conversion and frequency conversion, as well as the length measurement capability of 1550 nm window. By independently measuring the fiber temperature correction coefficient and wavelength correction coefficient the "normalized" corrections of fiber length changes caused by different temperature and wavelength of the test light source in communication window are realized, compared to other research results of fiber length standard reported in China, as well as a complete uncertainty evaluation, which provide experimental evidences, new ideas and methods for the traceability of fiber length in the field of OTDR calibration. The measurement uncertainties are U =(0.016+7.2×10-6L) m(k =2) at 1310 nm, and U =(0.028+7.2×10-6L) m(k =2) at 1550 nm respectively. And the uncertainty of calibrating by this standard a 14 km fiber used to OTDR transmission standard is 0.13 m(k=2), which is twice as good as the original device.
		2024 Vol. 45 (12): 1745-1752 [Abstract] ( 8 ) HTML (1 KB) PDF (0 KB) ( 2 )

	1753	Kinematic Calibration of Six-Axis Serial Robots Considering Joint Angle Error Compensation

		Existing robot kinematics calibration methods generally overlook the compensation of joint angle errors. Based on the analysis of experimental data on joint angle errors of six-axis serial robots, this paper proposes a compensation method for robot joint angle errors based on Chebyshev polynomial fitting, followed by the calibration of robot kinematics after compensating for joint angle errors. Subsequently, an experiment is conducted to validate joint angle error compensation and body kinematics calibration on the ABB IRB 1410 robot using a laser tracker. The experimental results show that the proposed method can reduce the mean absolute positioning error of the robot from the 2.11mm to 0.66mm. This research is expected to provide a theoretical foundation and technical conditions for further improving robot positioning accuracy.
		2024 Vol. 45 (12): 1753-1761 [Abstract] ( 4 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1762	Research on Compensation for Rotary Axis Rotation Error in Single Sensor-based Wafer Calibrator

		The primary technology for enhancing the positioning accuracy of the wafer calibrator involves compensating for the rotation error of the wafer calibrator rotation axis. This paper introduces a rotation error compensation method based on a single sensor, which effectively mitigates the introduction of new errors and multiple calibration issues associated with the use of multiple sensors and auxiliary equipment. This approach employs a dual filtering technique comprising ensemble averaging and wavelet threshold denoising to diminish random noise in the collected signal and accurately segregate the roundness error from the high signal-to-noise ratio measurement signal using mathematical and statistical error separation methods. Simultaneously, the precise rotation error is determined through a multi-position measurement method, and the error data is utilized to rectify the wafer circumference data detected by the sensor to achieve compensation. The experimental results show that after using the method proposed in this article, the calibration deviation of the wafer calibrator positioning is about 0.02mm,and enhances calibration accuracy, thereby validating its effectiveness.
		2024 Vol. 45 (12): 1762-1771 [Abstract] ( 4 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1772	Research on vehicle multi-target tracking algorithm based on UAV aerial video

		In order to improve the vehicle multi-target tracking accuracy under the UAV vision platform, this paper proposes a UAV visual vehicle multi-target tracking algorithm that combines the improved YOLOv7 network with the optimized ByteTrack algorithm. First of all, in view of the situation where the features of small targets are not obvious, the feature extraction ability of shallow semantic information of the YOLOv7 network is enhanced, and SIoU-Loss is used to optimize the coordinate loss function to speed up the convergence speed of the anchor frame; secondly, according to the vehicle motion characteristics, in Based on the ByteTrack algorithm, the state vector of the Kalman filter algorithm is integrated into the acceleration information; finally, the effectiveness of the algorithm is verified on the VisDrone2021 data set. The average detection accuracy of the improved YOLOv7 network is 3.2% higher than the original network, and the accuracy of the tracking algorithm is It is 1.2% higher than the baseline algorithm, and the high-order tracking accuracy is improved by 2.9%.
		2024 Vol. 45 (12): 1772-1779 [Abstract] ( 5 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1780	Research on the Calibration of Heat Flux Meters Using Guarded Hot Plate Apparatus

		The thermal resistance heat flow meter is widely used in the construction industry and industrial energy conservation. However, there is currently no standardized thermal flow measurement standard in China, and there is a lack of standardized heat sources, resulting in poor consistency in the measurement of thermal flow using thermal resistance heat flow meters. The guarded hot plate apparatus has the capability to generate precise and measurable unidirectional heat flow on the measurement plate. In this study, the calibration method of two foreign precision heat flow meters and two domestic heat flow meters was investigated using a high-performance single-sample guarded hot plate apparatus developed by the China Institute of Metrology. A 40 mm thick rock wool was used as the thermal resistance insulation material. Three different working conditions were designed: placing the test surface of the heat flow meter close to the measuring plate (Condition 1), placing it in the middle of the rock wool (Condition 2), and attaching it to the cold plate (Condition 3). The sensitivity coefficient C of each heat flow meter was measured. Under Condition 2, the measured value of C showed the smallest deviation from the indications of the two foreign heat flow meters, with a relative deviation of about 7%. The experimental results of all four heat flow meters consistently showed that Condition 2 had the lowest C value, while Condition 1 had the highest. Analysis indicated that the thermal conductivity of the organic solid material constituting the heat flow meter was greater than that of rock wool. Additionally, when in contact with the measuring plate or the cold plate, the resistance of the heat flow passing through the heat flow meter unit was smaller than that passing through the rock wool, resulting in non-unidirectional distribution of the heat flow and uneven distribution of the heat flow on the contact surface. The heat flow meter unit absorbed more heat flow, leading to an overestimation of the C value.
		2024 Vol. 45 (12): 1780-1786 [Abstract] ( 4 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1787	Research on the Application of A Permanent Surface Single Wellhead Conductance Array Multi-component Measurement Device for Oil Production

		In order to solve the urgent need and to fill the lack of monitoring devices for oil-gas-water three-phase flow parameters at the surface single wellhead for long-term, stable and reliable use in the field of petroleum production. The numerical simulation model of the developed monitoring device is established by the finite element method, and its structural parameters, electrical characteristics, sensitivity distribution and response characteristics are analyzed and optimized, so as to determine the optimal structure and optimal performance index of the monitoring device. On this basis, a permanent surface single wellhead conductance array multi-component measurement device （PSSWCAMMD_OP） was developed, and experimental research was carried out on the constructed conductance array multi-component measurement platform. The experimental results show that the measuring device has the characteristics of oil-gas-water three-phase flow conditions such as gas phase flow rate of 5-20m3/d, liquid phase flow rate of 30-70m3/d, and liquid phase water holdup of 70%-90%. Good multi-component measurement performance, multi-component measurement error is less than 3.7%.
		2024 Vol. 45 (12): 1787-1796 [Abstract] ( 4 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1797	Planar ECT image reconstruction based on 1-bit compressed sensing non convex algorithm

		In order to improve the imaging quality of planar capacitance imaging system, a planar ECT image reconstruction method based on 1-bit compressed sensing (1-bit CS) non convex algorithm is proposed. Firstly, discrete cosine basis (DCT) is used to sparsely represent grayscale values; Secondly, the maximum minimum concave penalty (MCP) is introduced as the regularization term, and the 1-bit CS MCP regularization model is established; Then, the near end operator of the dual solution is iteratively updated using the MCP non convex algorithm to obtain the optimal dual solution; Finally, calculate the reconstructed grayscale values based on the dual solution and perform image reconstruction. The simulation and experimental results show that compared with Tikhonov algorithm, Landweber algorithm and traditional compressed sensing algorithm, the average relative error and correlation coefficient of the reconstructed image obtained by the proposed method in this paper are 0.0496 and 0.9435 respectively, and the reconstruction time is within 0.2s, which is superior to the other three algorithms. The defect reduction degree and reconstruction speed have been significantly improved.
		2024 Vol. 45 (12): 1797-1803 [Abstract] ( 3 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1804	Research on L1+p-norm based regularization algorithm for ECT image reconstruction

		The regularization method is commonly used for image optimization in ECT. The L1-norm can excessively ignore the image features, and the L2-norm can make the image too smooth, both may reduce the image quality. To solve the problems above, proposed to use L1+p-norm (0
		2024 Vol. 45 (12): 1804-1810 [Abstract] ( 3 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1811	Non-intrusive drainage pipe flow measurement based on radar wave

		依据Continuous Wave（CW）雷达测位移原理和雷达波穿透性强的特点，在建立了一种传播路径与雷达波信号强度的关系模型的基础上，确立了液位与雷达波Intermediate Frequency(IF)信号的关系，提出了一种非侵入式管道中水流的液位测量方法，并根据曼宁公式计算重力流排水管道水流流速，实现了基于雷达波的非侵入式排水管道流量测量。通过与参考的电磁流量计测量数据比对，实验结果表明：提出的非侵入式流量测量方法的平均误差在3.5%以内，能满足绝大多数重力流的流量测量准确度要求。
		2024 Vol. 45 (12): 1811-1817 [Abstract] ( 5 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1818	Research on empty-heavy mixing loading matching and measurement algorithm of container trucks in railway freight yards

		In order to solve the problem of empty-heavy mixing loading matching and measurement difficulty of container trucks in railway freight yards, the method of weighing sensor combined with Beidou high-precision positioning was studied. The results showed that when two 20-inch containers were loaded in the same freight train, the operation status of the container was judged by the rising and falling edges, and the location was fitted according to the speed when the container was lost. Finally, the landing distance of two containers on one truck was about 6000 mm, which was consistent with the length of the outer diameter of the 20-inch container. Torque balancing calculation was carried out on eight force points of the two containers, and the off-load bias state of the two containers was transformed into the whole vehicle metering state. The average error of the total weight was 0.4%, the average error of the X-direction bias was 0.3t, and the average error of the Y-direction offset was 3.46mm.
		2024 Vol. 45 (12): 1818-1823 [Abstract] ( 3 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1824	Simulation Mooring Lines Tension Prediction Based on Improved Resnet-LSTM Model

		To solve the tension prediction problem when the structure of the ocean floating platform mooring system was subjected to various linear and nonlinear forces in the complex and changeable operating environment, for improving the hidden layers, iteration times and learning rate parameters of the LSTM model based on long short term memory algorithm, the Resnet-LSTM model with convolution muti-layer features extraction inserted different thresholds’ residual module was established. The floating platform was regarded as an overall force loaded on the mooring lines to analysis nonlinear feature while influential factors of mooring lines tension were considered and the environment loads factors were calculated. After the muti-points mooring system was setup and solved under different ocean conditions, trained and predicted the lines tension data which came from datasets with three different models LSTM, Resnet-LSTM and improved Resnet-LSTM. Experiment comparative results showed that the Resnet-LSTM indicators of accuracy was up 0.9973, the parameters of network were optimized which proved the model based on improved Resnet-LSTM could effectively increase the prediction result of the model in nonlinear data processing of multi-points mooring lines system tension with some improvement value.
		2024 Vol. 45 (12): 1824-1831 [Abstract] ( 3 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1832	Research on fault diagnosis of rolling bearing based on MPGCN-Resnet

		Rolling bearings are installed in various machine tools and other production machinery, and are prone to faults and failures, requiring continuous monitoring to ensure their safe and reliable operation. In this paper, a multiple parallel graphs convolutional neural residual network (MPGCN-Resnet) is designed to complete the fault diagnosis of rolling bearings. This method consists of four parts. Among them, the time-frequency graph acquisition part based on Cmor wavelet can complete refined processing of reconstruction and disassembly in various fault vibration signals. The feature acquisition part based on a multi-parallel network can improve generalization and accelerate convergence. The feature learning part under the residual structure graph neural network can utilize the residual structure to complete feature learning and can realize the in-depth exploration of fault characteristics of rolling bearings. The GAP-Softmax fault classification part can complete the effective diagnosis of rolling bearing faults. The CWRU bearing data set is selected to complete the comparison and analysis experiments of this method and the IHDSVM-Alexnet and MSATM methods in terms of variable working conditions, variable noise, accuracy, and loss values. The results show that the average fault diagnosis accuracy of this method for rolling bearings can reach 96.4%, which is higher than 91% in a -6 dB noise environment and greater than 90% when the load suddenly changes by 3×0.75KW. This method has higher fault diagnosis accuracy for rolling bearings in various variable working conditions and variable noise environments than the other two methods, and can alleviate the problems of increased parameters and excessive calculation.
		2024 Vol. 45 (12): 1832-1840 [Abstract] ( 3 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1841	Noise Characteristic Study of 2.2 MW Large Wind Turbine Based on Hilbert-Huang Transform

		To measure the aerodynamic noise of a 2.2 MW horizontal-axis wind turbine, six measurement points were set up in a large wind farm. The points were placed in the upwind, downwind, and at a 60° angle around the turbine. The trends of total sound pressure level (TSPL) of measurement points were obtained by 1/3 octave analysis under the wind speeds ranging from 6.55-15.00 m/s. On the basis, the empirical modal decomposition and Hilbert transform, combined with the marginal spectra, are applied to obtain the key time-frequency characteristics of wind turbine noise. The results show that the total sound pressure levels at the 60° measurement points are similar to those of the standard measurement points in the same direction. However, the noise level at measurement point #4, located upwind of the wind turbine, is relatively lower. The variance contribution ratio and correlation coefficient derived from the empirical modal decomposition reveal that the primary energy of the noise is concentrated in the frequency band of 770~1120 Hz. The principal frequency of the fitted marginal spectrum is in good agreement with the cubic relationship of the corresponding wind speed.
		2024 Vol. 45 (12): 1841-1848 [Abstract] ( 5 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1849	Study on Sound Pressure Measurement Based on Photon Auto-correlation Method

		In order to solve the problem that the correlation delay time (τ) of the traditional autocorrelator-based experimental system is too large when detecting the air free-field sound pressure, an anechoic box environment was built, a non-fixed-frequency-shift optical system, and a signal acquisition and processing system were designed for detecting the air free-field sound pressure based on the photon correlation method. The method decreases the step value of autocorrelation delay time (τ) to 1 μs, reducing the measurement error of sound pressure by 0.2 dB compared to traditional autocorrelator-based experimental systems. Comparing the measurement results of air field sound pressure between the microphone method and the optical autocorrelation method for 106.4 dB sound waves in the frequency range of 600 to 1200 Hz, the maximum deviation in measurement is 0.6 dB.
		2024 Vol. 45 (12): 1849-1854 [Abstract] ( 4 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1855	Development of an on-chip Power Divider for the Quantum Voltage Chip

		Using the power divider in the quantum voltage chip is an important method to improve the quantum output amplitude of the quantum chip. The π-type LC circuit can achieve a small on-chip Wilkinson power divider, and add a?λ/4 converter to broaden the working bandwidth. Developing an on-chip broadband Wilkinson power divider based on the design simulation. In the range of 13GHz to 23GHz, the power allocation is given in 3.0±0.25dB. In the range of 12 GHz to 23 GHz, its input and output reflections are respectively below -12 dB and -10.5 dB. In the range of 1.5 GHz-30 GHz, three arrays with power divider are irradiated by microwave. The test result shows that the three Josephson junction arrays are the same, proving that the power divider can effectively achieve two-way equal output.
		2024 Vol. 45 (12): 1855-1861 [Abstract] ( 8 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1862	Dual-band resonant complex permittivity sensor based on interdigital capacitor structure

		A dual-frequency resonant sensor is designed based on the interdigital capacitance structure to measure the complex permittivity of liquid. The advantages of the sensor in sensitivity, miniaturization and operating bandwidth are verified by simulation analysis, machining and measurement. The results of simulation and measurement show that the sensitivity of the dual-band resonant sensor is as high as 5.2%, which can realize the nondestructive measurement of the complex permittivity of the liquid at two frequency points with a very small amount of liquid at the same time, and can measure the concentration of methanol-ethanol mixed solution based on certain calibration operations. The measurement error of liquid complex permittivity is reduced from 4.2% to 2% by obtaining the test data of two frequency points simultaneously. In addition, the structure size of the interdigital capacitor can be further adjusted to develop a multi-band resonant sensor to achieve accurate acquisition of the wide-band dielectric spectrum of the liquid.
		2024 Vol. 45 (12): 1862-1867 [Abstract] ( 6 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1868	Identification of Synchronous Motor Parameters Using Multi-link improvement Harris Hawks Optimization

		Aiming at the problems of the traditional methods in the field of parameter identification of permanent magnet synchronous motor (PMSM), it is difficult to identify multiple parameters at the same time and the identification accuracy is not high enough, parameter identification algorithm was proposed, in which the Harris Eagle optimization algorithm is adopted. In order to improve the accuracy and stability of the identification algorithm, this thesis improves the Harris Eagle algorithm from three aspects: First, the position of the eagle colony is initialized by introducing Logistic chaotic mapping from the direction of population initialization, increasing the diversity of the population and speeding up the convergence of the identification algorithm. Secondly, from the perspective of eagle position update, the random reverse learning strategy is used to optimize the worst position individual in the eagle group, so as to improve the fuzziness and randomness of the algorithm, enhance the global search performance, and make the identification results more accurate. Finally, in order to prevent premature convergence, the current optimal individual position is retained into the next iteration to improve the problem that the traditional Harris Eagle algorithm is prone to local optimization and precision decline. On the basis of the mathematical model based on PMSM voltage equation, MIHHO algorithm and standard Harris Eagle algorithm (HHO), particle swarm optimization (PSO) and Sparrow search algorithm (SSA) are tested.The results show that MIHHO algorithm has better stability, convergence speed and higher identification accuracy for PMSM parameter identification.
		2024 Vol. 45 (12): 1868-1875 [Abstract] ( 6 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1876	Traffic Signal Control Based on an Improved Chaotic Particle Swarm Algorithm

		The PSO algorithm is widely adopted for addressing traffic signal control (TSC) issues. However, traditional PSO-based TSC methods exhibit limitations. Firstly, the global search capability of particles in the PSO algorithm is insufficient, and it is easy to prematurely converge to a local optimal solution. Secondly, traffic signal control models operating on fixed cycle times lack flexibility in coping with under-saturated or over-saturated traffic conditions as traffic volume fluctuates over time. To address these concerns, this paper proposed a TSC method employing an ICPSO algorithm. The ICPSO algorithm utilized chaotic motion to overcome the local optimum problem and to enhance global search capabilities. It also incorporated a neighborhood radius parameter to perform chaotic searches in the vicinity of elite particles with higher fitness levels, preserving their advantageous characteristics and enabling them to escape local optima traps. Moreover, we have designed a VTSC model that dynamically adjusts signal cycle lengths based on time-varying traffic volume, offering flexible responses to complex traffic conditions. To evaluate the practical performance of the ICPSO algorithm based on the VTSC model, an exhaustive series of experiments were conducted using the traffic simulation software VISSIM. Experimental results indicate that our proposed method significantly outperforms other algorithms in key performance indicators such as average queue length and average number of stops, and effectively enhances the traffic efficiency of road networks.
		2024 Vol. 45 (12): 1876-1884 [Abstract] ( 5 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1885	Small Cesium Atomic Fountain Clock for Time Keeping System

		Atomic clocks with good long-term stability are very important for timekeeping systems. Due to its excellent long-term stability performance, the small cesium atomic fountain clock also has the advantages of high reliability, automation, miniaturization, and mobility. It has the potential to realize a mobile timekeeping in a vehicle-mounted form and can be used as a node clock in a timekeeping atomic clock group, ensuring accurate frequency signals and time signals. This article introduces the design and operation results of the small cesium atomic fountain clock NIM-TF3 developed by the National Institute of Metrology of China. The frequency stability of NIM-TF3 is 2.7×10-13@ 1 second and 5.3×10-15@ 1 day. NIM-TF3 adopts an integrated laser system and an integrated electronic control system, which can achieve long-term automatic continuous operation. It also integrates the developed small microwave frequency synthesizer with the physical system, which significantly reduces the system volume and enhances the overall stability. and reliability. We also evaluated the second-order Zeeman relative frequency shift caused by the uneven distribution of the C field to be 7.3×10-14, with an uncertainty of 0.2×10-15. The overall volume of NIM-TF3 is less than 0.7 m3 and has the potential to become a vehicle-mounted fountain clock.
		2024 Vol. 45 (12): 1885-1891 [Abstract] ( 4 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1892	Research on traceability method of voltage and measurement of medical breast tube

		Abstract:With the continuous improvement of the diagnostic X-ray quality evaluation system, tube voltage has become an equally important index for evaluating the quality of X-ray radiation beams such as half-value layer, homogeneity coefficient and equivalent tissue depth. In this paper, the measurement method and traceability method of medical breast tube voltage are mainly studied. Two methods are used to measure the tube voltage, namely the interventional voltage divider box voltage division method and the energy spectrum endpoint method. The measurement results are quantitatively transmitted to several semiconductor standard detectors commonly used in the market. The experimental results show that the maximum difference between the two methods of tube voltage measurement is within 1.0%, which is reliable. The voltage measurement results of four semiconductor detector tubes commonly used in the domestic market were calibrated, and the deviation of the relative inherent error was within 2.0%, which can be used for on-site quality control of medical breast machines.
		2024 Vol. 45 (12): 1892-1899 [Abstract] ( 1 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1900	Surface electromyography gesture recognition based on personalized feature analysis

		To realize artificial limb control, it is an important method to use surface electromyography (sEMG) signal to recognize gestures. sEMG signals are electromyographic signals collected from the surface layer of the skin, which can reflect the neuromuscular activities to a certain extent. Due to its random and non-smooth characteristics, the use of sEMG signals to control artificial intelligent prosthetic limbs has never been able to achieve the desired results, especially reflected in the influence of individual differences such as gender. In this paper, a gesture recognition method based on surface EMG signals is proposed for seven types of gesture movements through differentiated gender characterization. Experimental results show that the recognition accuracy of the method is significantly improved in all five classifiers. Among them, linear discriminant analysis has the most significant improvement, reaching 15.84%; support vector machine and extreme gradient boosting are the most effective in gesture recognition, with an accuracy of 98.41%.
		2024 Vol. 45 (12): 1900-1908 [Abstract] ( 6 ) HTML (1 KB) PDF (0 KB) ( 1 )

	1909	Non-SI units in the SI and their use with SI prefixes

		The International System of Units (SI) is one of the greatest scientific, technological, and political achievements of recent times. After the formal introduction of the SI, it was necessary to accept the ongoing usage of some non-SI units because of their long history of previous use, despite this losing the benefit of coherence that the SI brings. This work reviews the history of non-SI units that have been allowed for use with the SI in successive SI Brochures, observes the rules that have been required for this use especially with SI prefixes, and notes that this set of non-SI units has decreased significantly as the SI has become more deeply embedded in modern society. The current situation, where a relatively small set of non-SI units remain accepted for use with the SI, is analyzed. It is observed that these non-SI units acquire quasi-SI status because of their listing in the SI Brochure. As a result, it is proposed that this set of non-SI units should be as small as possible and that clear rules for their use are necessary, most obviously with SI prefixes where the current guidance needs improvement. Historical precedent has been examined to assist in shaping these recommendations, which could be discussed and considered when the SI Brochure is next updated.
		2024 Vol. 45 (12): 1909-1916 [Abstract] ( 2 ) HTML (1 KB) PDF (0 KB) ( 1 )

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