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  • 1  Mach Number Prediction for a Wind Tunnel Based on the CNN-LSTM-Attention Method
    ZHAO Luping WU Kunyang
    2023(4):64-82. DOI: 10.15878/j.cnki.instrumentation.2023.04.002
    [Abstract](53) [HTML](0) [PDF 12.87 M](6304)
    Abstract:
    The test section’s Mach number in wind tunnel testing is a significant metric for evaluating system performance. The quality of the flow field in the wind tunnel is contingent upon the system's capacity to maintain stability across various working conditions. The process flow in wind tunnel testing is inherently complex, resulting in a system characterized by nonlinearity, time lag, and multiple working conditions. To implement the predictive control algorithm, a precise Mach number prediction model must be created. Therefore, this report studies the method for Mach number prediction modelling in wind tunnel flow fields with various working conditions. Firstly, this paper introduces a continuous transonic wind tunnel. The key physical quantities affecting the flow field of the wind tunnel are determined by analyzing its structure and blowing process. Secondly, considering the nonlinear and time-lag characteristics of the wind tunnel system, a CNN-LSTM model is employed to establish the Mach number prediction model by combining the 1D-CNN algorithm with the LSTM model, which has long and short-term memory functions. Then, the attention mechanism is incorporated into the CNN-LSTM predic-tion model to enable the model to focus more on data with greater information importance, thereby enhancing the model's training effectiveness. The application results ultimately demonstrate the efficacy of the proposed approach.
    2  Vibration Measurement of Pedestrian Bridge Using Double Magnetic Suspension Vibrator Based on Wavelet Analysis
    JIANG Dong KONG Deshan ZHANG Zhengnan WANG Deyu
    2017, 4(3):14-23.
    [Abstract](1938) [HTML](0) [PDF 13.79 M](5069)
    Abstract:
    Aiming at the problem of pedestrian bridge vibration measurement, a vibration measurement system of pedestrian bridge with dual magnetic suspension vibrator structure was designed according to absolute vibration measurement principle. The relationship between the magnetic repulsion force of vibrator and its displacement was obtained by the experimental method and the least square fitting method. The vibration equations of two magnetic suspension vibrators were deduced respectively, and the measurement sensitivity of the system was deduced. The amplitude-frequency characteristic of the system was studied. A simulation model of vibrator measurement system with double magnetic suspension vibrator was established. The analysis shows that the sensitivity of the vibration measurement system with double magnetic suspension vibrator is higher than that with single magnetic suspension vibrator. The four vibration waveforms were measured, that is, no one passes through a pedestrian bridge, there are cars running under the pedestrian bridge, single pedestrian passes through the pedestrian bridge and multiple pedestrians pass through the pedestrian bridge. The multi-scale one-dimensional wavelet decomposition function was used to analyze the vibration signals. The vibration characteristics were obtained using one dimension wavelet decomposition function under four different conditions. Finally, the vibration waveforms of four cases were reconstructed. The measured results show that the vibration measurement system of pedestrian bridge with double magnetic suspension vibrator structure has high measurement sensitivity. The design has a certain value to monitor a pedestrian bridge.
    3  Research on the Crack Detection of Conductive Components Using Pulsed Eddy Current Thermography
    ZHOU Deqiang CHANG Xiang DU Yang CAO Piyu WANG Hua ZHANG Hong
    2017, 4(3):59-68.
    [Abstract](1380) [HTML](0) [PDF 10.00 M](4247)
    Abstract:
    Crack of conductive component is one of the biggest threats to daily production. In order to detect the crack on conductive component, the pulsed eddy current thermography models were built according to different materials with the cracks based on finite element method (FEM) simulation. The influence of the induction heating temperature distribution with the different defect depths were simulated for the carbon fiber reinforced plastic (CFRP) materials and general metal materials. The grey value of image sequence was extracted to analyze its relationship with the depth of crack. Simulative and experimental results show that in the carbon fiber reinforced composite materials, the bigger depth of the crack is, the larger temperature rise of the crack during the heating phase is; and the bigger depth of the crack is, the faster the cooling rate of the crack during the cooling phase is. In general metal materials, the smaller depth of the crack is, the lager temperature rise of the crack during the heating phase is; and the smaller depth of the crack is, the faster the cooling rate of crack during the cooling phase is.
    4  A Practical Pll-Based Drive Circuit with Ultra-Low-Noise Tia for Mems Gyroscope
    CHEN Hua ZHONG Yanqing MENG Zhen
    2017, 4(3):7-13.
    [Abstract](2251) [HTML](0) [PDF 8.76 M](4110)
    Abstract:
    A novel phase-locked loop (PLL) -based closed-loop driving circuit with ultra-low-noise trans-impedance amplifier (TIA) is proposed. The TIA is optimized to achieve ultra-low input-referred current noise. To track drive-mode resonant frequency and reduce frequency jitter of actuation voltage, a PLL-based driving technique is adopted. Implemented on printed circuit board (PCB), the proposed driving loop has successfully excited MEMS element into resonance, with a settling time of 3s. The stable frequency and amplitude of TIA output voltage are 10.14KHz and 800mVPP, respectively. With sense-channel electronics, the gyroscope exhibits a scale factor of 0.04mV/°/s and a bias instability of 57.6°/h, which demonstrates the feasibility of the proposed driving circuit.
    5  Detection of Contamination Defect on Ice Cream Bar Based on Fuzzy Rule and Absolute Neighborhood
    LI Shaoli YUAN Weiqi
    2017, 4(3):24-34.
    [Abstract](2094) [HTML](0) [PDF 8.44 M](3450)
    Abstract:
    The contamination proposed in this paper is a defect on the surface of ice cream bar, which is a serious security threat. So it is essential to detect this defect before launched on the market. A detection method of contamination defect on the ice cream bar surface is proposed, which is based on fuzzy rule and absolute neighborhood feature. Firstly, the ice cream bar surface is divided into several sub-regions via the defined adjacent gray level clustering method. Then the alternative contamination regions are extracted from the sub-regions via the defined fuzzy rule. At last, the real contamination regions are recognized via the relationship between absolute neighborhood gray feature and default threshold. The algorithm was tested in the self-built image database SUT-D. The results show that the accuracy of the method proposed in this paper is 97.32 percent, which increases 2.68 percent at least comparing to the other typical algorithms. It indicates that the superiority proposed in this paper, which is of actual use value.
    6  Iris Segmentation Based on Matting
    CHEN Qiru WANG Qi SUN Ting WANG Ziyuan
    2022, 9(1):12-22. DOI: 10.15878/j.cnki.instrumentation.2022.01.003
    [Abstract](709) [HTML](0) [PDF 3.00 M](3222)
    Abstract:
    In this paper, we aim to propose a novel and effective iris segmentation method that is robust to uneven light intensity and different kinds of noises such as occlusion by light spots, eyelashes, eyelids, spectacle-frame, etc. Unlike previous methods, the proposed method makes full use of gray intensities of the iris image. Inspired by the matting algorithm, a premier assumption is made that the foreground and background images of the iris image are both locally smooth. According to the RST algorithm, trimaps are built to provide priori information. Under the assumption and priori, the optimal alpha matte can be obtained by least square loss function. A series of effective post processing methods are applied to the alpha image to obtain a more precise iris segmentation. The experiment on CASIA-iris-thousand database shows that the proposed method achieves a much better performance than conventional methods. Our experimental results achieve 20.5% and 26.4%, more than the well-known integro-differential operator and edge detection combined with Hough transform on iris segmentation rate respectively. The stability and validity of the proposed method is further demonstrated through the complementary experiments on the challenging iris images.
    7  Research on Hand-eye Calibration Technology of Visual Service Robot Grasping Based on ROS
    LI Shengqian ZHANG Xiaofan
    2022, 9(1):23-30. DOI: 10.15878/j.cnki.instrumentation.2022.01.002
    [Abstract](670) [HTML](0) [PDF 1.51 M](3170)
    Abstract:
    For the hand-eye calibration of the vision service robot, the traditional hand-eye calibration technology can’t be realized which because the service robot is independently developed and there is no teaching device to feed back the pose in-formation of the service robot in real time. In this paper, a hand-eye calibration method based on ROS (Robot Operating System) is proposed. In this method, ROS system is used to accurately control the arm of the service robot to rotate in different positions for many times. Meanwhile, the head camera of the service robot takes images of a fixed point in the scene. Then, the nonlinear equations were established according to the homography matrix of the two images and the position and pose information of the ROS system, and the accurate hand-eye relationship was optimized by the least square method. Finally, an experimental platform is built and the proposed hand-eye calibration method is verified. The experiment results show that the method is easy to operate, simple algorithm and correct result, which verifies the ef-fectiveness of the algorithm and provides conditions for the realization of humanoid grasping of visual service robot.
    8  Capacitive micromachined ultrasonic transducer as a resonant temperature sensor
    LI Zhikang Rahman.hebibul ZHAO Libo YE Zhiying LI Ping ZHAO Yulong JIANG Zhuangde
    2014, 1(3):67-74.
    [Abstract](1186) [HTML](0) [PDF 1.48 M](3063)
    Abstract:
    Resonant temperature sensors have drawn considerable attention for their advantages such as high sensitivity, digitized signal output and high precision. This paper presents a new type of resonant temperature sensor, which uses capacitive micromachined ultrasonic transducer (CMUT) as the sensing element. A lumped electro-mechanical-thermal model was established to show its working principle for temperature measurement. The theoretical model explicitly explains the thermally induced changes in the resonant frequency of the CMUT. Then, the finite element method was used to further investigate the sensing performance. The numerical results agree well with the established analytical model qualitatively. The numerical results show that the resonant frequency varies linearly with the temperature over the range of 20 ℃ to 140℃ at the first four vibrating modes. However, the first order vibrating mode shows a higher sensitivity than the other three higher modes. When working at the first order vibrating mode, the temperature coefficient of the resonance frequency (TCf) can reach as high as -1114.3 ppm/℃ at a bias voltage equal to 90% of the collapse voltage of the MCUT. The corresponding nonlinear error was as low as 1.18%. It is discovered that the sensing sensitivity is dependent on the applied bias voltages. A higher sensitivity can be achieved by increasing the bias voltages.
    9  Research on Surface Defect Detection Technology of Wind Turbine Blade Based on UAV Image
    TAN Xingguo ZHANG Gaoming
    2022, 9(1):41-48. DOI: 10.15878/j.cnki.instrumentation.2022.01.004
    [Abstract](484) [HTML](0) [PDF 2.27 M](3049)
    Abstract:
    In the background of “double carbon,” vigorously developing new energy is particularly important. Wind power is an important clean energy source. In the field of new energy, wind power scale is also expanding. With the wind turbine, the probability of large-scale blade damage is also increasing. Because the large wind turbine blade crack detection cost is high and because of the poor working environment, this paper proposes a wind turbine blade surface defect detection method based on UAV acquisition images and digital image processing. The application of weighted averages to achieve grayscale processing, followed by median filtering to achieve image noise reduction, and an improved histogram equalization algorithm is proposed and used for the characteristics of the UAV acquisition images, which enhances the image by limiting the contrast adaptive histogram equalization algorithm to make the details at the target area and defects more clear and complete, and improves the detection efficiency. The detection of the blade surface is achieved by separating and extracting the feature information from the defects through image foreground segmentation, threshold processing, and framing by the connected domain. The validity and accuracy of the proposed method in leaf detection were verified by experiments.
    10  Non-destructive Testing Method for Crack Based on Diamond Nitrogen-vacancy Color Center
    ZHAO Long WANG Xin ZHAO Bowen WU Guiyuan LUO Dacheng ZHANG Shaochun
    2022, 9(1):56-64. DOI: 10.15878/j.cnki.instrumentation.2022.01.006
    [Abstract](878) [HTML](0) [PDF 6.19 M](3048)
    Abstract:
    Magnetic field measurement plays an extremely important role in material science, electronic engineering, power system and even industrial fields. In particular, magnetic field measurement provides a safe and reliable tool for in-dustrial non-destructive testing. The sensitivity of magnetic field measurement determines the highest level of detec-tion. The diamond nitrogen-vacancy (NV) color center is a new type of quantum sensor developed in recent years. The external magnetic field will cause Zeeman splitting of the ground state energy level of the diamond NV color center. Optical detection magnetic resonance (ODMR), using a microwave source and a lock-in amplifier to detect the resonant frequency of the NV color center, and finally the change of the resonant frequency can accurately calcu-late the size of the external magnetic field and the sensitivity of the external magnetic field change. In the experiment, a diamond containing a high concentration of NV color centers is coupled with an optical fiber to realize the prepara-tion of a magnetic field scanning probe. Then, the surface cracks of the magnetized iron plate weld are scanned, and the scanning results are drawn into a two-dimensional magnetic force distribution map, according to the magnetic field gradient change of the magnetic force distribution map, the position and size of the crack can be judged very accurately, which provides a very effective diagnostic tool for industrial safety.
    11  Target Path Tracking Method of Intelligent Vehicle Based on Competitive Cooperative Game
    SONG Chongzhi NIU Limin
    2022, 9(1):31-40. DOI: 10.15878/j.cnki.instrumentation.2022.01.007
    [Abstract](525) [HTML](0) [PDF 1.62 M](2933)
    Abstract:
    To improve intelligent vehicle drive performance and avoid vehicle side-slip during target path tracking, a linearized four-wheel vehicle model is adopted as a predictive control model, and an intelligent vehicle target path tracking method based on a competitive cooperative game is proposed. The design variables are divided into different strategic spaces owned by each player by calculating the affecting factors of the design variables with objective functions and fuzzy clustering. Based on the competitive cooperative game model, each game player takes its payoff as a mono-objective to optimize its own strategic space and obtain the best strategy to deal with others. The best strategies were combined into the game strategy set. Considering the front wheel angle and side slip angle increment constraint, tire side-slip angle, and tire side slip deflection dynamics, it took the path tracking state model was used as the objective, function and the calculation was validated by competitive cooperative game theory. The results demonstrated the effectiveness of the proposed algorithm. The experimental results show that this method can track an intelligent vehicle quickly and steadily and has good real-time performance.
    12  Structural Design of High-precision Positioning System in Weak Signal Environment Based on UWB and IMU Fusion
    ZHAO Yang WANG Tianhu LI Wenjie MIAO Qiannian SHEN Yunzhe HUANG Tao
    2023(2):30-39. DOI: 10.15878/j.cnki.instrumentation.2023.02.001
    [Abstract](58) [HTML](0) [PDF 3.80 M](2838)
    Abstract:
    Aiming at the problem that indoor positioning technology based on wireless ultra-wideband pulse technology is susceptible to non-line-of-sight effects and multipath effects in confined spaces and weak signal environments, a high-precision positioning system based on UWB and IMU in a confined environment is designed. The STM32 chip is used as the main control, and the data information of IMU and UWB is fused by the fusion filtering algorithm. Finally, the real-time information of the positioning is transmitted to the host computer and the cloud. The experimental results show that the positioning accuracy and positioning stability of the system have been improved in the non-line-of-sight case of closed environment. The system has high positioning accuracy in a closed environment, and the components used are consumer-grade, which has strong practicability.
    13  BP-PID Control Applied in Evaporator of Organic Rankine Cycle System
    WANG Zhigang GUO Shuang
    2017, 4(3):54-58.
    [Abstract](2108) [HTML](0) [PDF 2.44 M](2805)
    Abstract:
    According to the problem that the selection of traditional PID control parameters is too complicated in evaporator of Organic Rankine Cycle system (ORC), an evaporator PID controller based on BP neural network optimization is designed. Based on the control theory, the model of ORC evaporator is set up. The BP algorithm is used to control the , and parameters of the evaporator PID controller, so that the evaporator temperature can reach the optimal state quickly and steadily. The MATLAB software is used to simulate the traditional PID controller and the BP neural network PID controller. The experimental results show that the , and parameters of the BP neural network PID controller are 0.5677, 0.2970, and 0.1353, respectively. Therefore, the evaporator PID controller based on BP neural network optimization not only satisfies the requirements of the system performance, but also has better control parameters than the traditional PID controller.
    14  Modeling of a wireless saw temperature sensor and associated antenna
    Laurent ALLIES Eloi BLAMPAIN Hamid M’JAHED Gérard PRIEUR Omar ELMAZRIA
    2014, 1(1).
    [Abstract](833) [HTML](0) [PDF 8.46 M](2800)
    Abstract:
    Surface acoustic wave (SAW) resonator used as wireless sensor was characterized and the parameters of its MBVD ((Modified Butterworth-Van Dyke) model were extracted versus temperature. The extracted parameters lead to evaluate the resonator performances in terms of Temperature coefficient of frequency (TCF) and quality factor (Q). An antenna was then associated with the SAW resonator and the entire system has been characterized and modeled. The good agreement experiment-simulation allows to define the optimum operating conditions of the wireless sensor.
    15  Development and Application of Working Standard Pyranometer
    MO Yueqin LV Wenhua QUAN Jimei
    2017, 4(3):35-39.
    [Abstract](1796) [HTML](0) [PDF 3.21 M](2782)
    Abstract:
    Using the temperature compensation and structure optimization design technology, developed the TBQ-2-B type standard pyranometer on the original pyranometer basis, its stability is better than 2%, reached the international standard ISO 9060 and the World Meteorological Organization (WMO) instruments and methods of observation Committee (CIMO) on the first level pyranometer request. Over the years, comparing with our national solar radiation standard (absolute cavity radiometer), its performance is very stable. As a working standard pyranometer, it has been used for more than twenty years in the field of metrological calibration of meteorological radiation instruments.
    16  Research on dynamic performance of star tracker
    SUN Ting XING Fei YOU Zheng
    2015, 2(1):17-26.
    [Abstract](933) [HTML](0) [PDF 3.70 M](2704)
    Abstract:
    Abstract: This manuscript briefly summarizes the development trends and recent research focus of the star tracker. And the relevant technologies about dynamic performance of the star tracker are analyzed and discussed. These can provide reference for the star tracker and attitude measurement device researchers.
    17  Contrastive Observation of Solar Thermal and Photovoltaic Resource
    BIAN Zeqiang LV Wenhua CHONG Wei
    2017, 4(3):1-6.
    [Abstract](2249) [HTML](0) [PDF 1.84 M](2413)
    Abstract:
    Solar thermal and photovoltaic applications are the most widely used and the most successful way of commercial development in solar energy applications. Observation and assessment of solar thermal and photovoltaic resources are the basis and key of their large-scale development and utilization. Using the observational data carried out from Beijing southern suburbs observation station of China Meteorological Administration in summer of 2009, preliminary solar thermal and photovoltaic resources characteristics for different weather conditions, different angle and different directions are analyzed. The results show that: (1) In sunny, cloudy or rainy weather conditions, both of solar thermal and photovoltaic sensors daily irradiance have consistent change in trend. Solar thermal irradiance is larger than photovoltaic. Under sunny conditions, solar thermal global radiation has about 2.7% higher than the photovoltaic global radiation. Under cloudy weather conditions, solar thermal global radiation has about 3.9% higher than the photovoltaic. Under rainy weather conditions, solar thermal global radiation has about 20% higher than the photovoltaic. (2) For different inclined plane daily global radiation, southern latitude -15 °incline is the maximum and southern vertical surface is the minimum. The order from large to small is southern latitude-15 ° incline, southern latitude incline, southern latitude+15 °incline, horizontal surface and southern vertical surface. Southern latitude -15 °incline global radiation has about 41% higher than the southern vertical surface. (3) For different orientation vertical surface daily global radiation, southern vertical surface is the maximum and western vertical surface is the minimum, which eastern vertical surface is in the middle. Southern vertical surface global radiation has about 20% higher than the western vertical surface.
    18  Overview of one transistor type of hybrid organic ferroelectric non-volatile memory
    Young Tea Chun Daping Chu
    2015, 2(1):65-74.
    [Abstract](820) [HTML](0) [PDF 12.96 M](2221)
    Abstract:
    Abstract: Organic ferroelectric memory devices based on field effect transistors that can be configured between two stable states of on and off have been widely researched as the next generation data storage media in recent years. This emerging type of memory devices can lead to a new instrument system as a potential alternative to previous non-volatile memory building blocks in future processing units because of their numerous merits such as cost-effective process, simple structure and freedom in substrate choices. This bi-stable non-volatile memory device of information storage has been investigated using several organic or inorganic semiconductors with organic ferroelectric polymer materials. Recent progresses in this ferroelectric memory field, hybrid system have attracted a lot of attention due to their excellent device performance in comparison with that of all organic systems. In this paper, a general review of this type of ferroelectric non-volatile memory is provided, which include the device structure, organic ferroelectric materials, electrical characteristics and working principles. We also present some snapshots of our previous study on hybrid ferroelectric memories including our recent work based on zinc oxide nanowire channels.
    19  Control of a 6DOF Mobile Manipulator with Object Detection and Tracking Using Stereo Vision
    P.W.S.I. Wijethunga I.A. Chandrawansa B.M.D.T. Rathnayake W.A.N.I.Harischandra W.M.M.T.S. Weerakoon B.G.L.T. Samaranayake
    2021, 8(1):1-13. DOI: 10.15878/j.cnki.instrumentation.2021.01.001
    [Abstract](1021) [HTML](0) [PDF 77.55 M](2180)
    Abstract:
    A supportive mobile robot for assisting the elderly is an emerging requirement mainly in countries like Japan where population ageing become relevant in near future. Falls related injuries are considered as a critical issue when taking into account the physical health of older people. A personal assistive robot with the capability of picking up and carrying objects for long/short distances can be used to overcome or lessen this problem. Here, we design and introduce a 3D dynamic simulation of such an assistive robot to perform pick and place of objects through visual recognition. The robot consists of two major components; a robotic arm or manipulator to do the pick and place, and an omnidirectional wheeled robotic platform to support mobility. Both components are designed and operated according to their kinematics and dynamics and the controllers are integrated for the combined performance. The objective was to improve the ac-curacy of the robot at a considerably high speed. Designed mobile manipulator has been successfully tested and sim-ulated with a stereo vision system to perform object recognition and tracking in a virtual environment resembling aroom of an elderly care. The tracking accuracy of the mobile manipulator at an average speed of 0.5m/s is 90% and is well suited for the proposed application.
    20  Simulation of Crowd Motion Based on Boids Flocking Behavior and Social Force Model
    ZHANG Xuguang ZHU Yanna
    2021, 8(1):29-42. DOI: 10.15878/j.cnki.instrumentation.2021.01.003
    [Abstract](714) [HTML](0) [PDF 86.79 M](2175)
    Abstract:
    In the process of crowd movement, pedestrians are often affected by their neighbors. In order to describe the consistency of adjacent individuals and collectivity of a group, this paper learns from the rules of the flocking behavior, such as segregation, alignment and cohesion, and proposes a method for crowd motion simulation based on the Boids model and social force model. Firstly, the perception area of individuals is divided into zone of segregation, alignment and cohesion. Secondly, the interactive force among individuals is calculated based upon the zone information, velocity vector and the group information. The interactive force among individuals is the synthesis of three forces: the repulsion force to avoid collisions, the alignment force to keep consistent with the velocity direction, and the attractive force to get close to the members of group. In segregation and alignment areas, the repulsion force and alignment force among pedestrians are limited by visual field factors. Finally, the interactive force among individuals, the driving force of destination and the repulsion force of obstacles work together to drive the behavior of crowd motion. The simulation results show that the proposed method can not only effectively simulate the interactive behavior between adjacent individuals but also the collective behavior of group.

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