Proceedings Volume 11930

International Conference on Mechanical Engineering, Measurement Control, and Instrumentation

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Proceedings Volume 11930

International Conference on Mechanical Engineering, Measurement Control, and Instrumentation

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Volume Details

Date Published: 14 October 2021
Contents: 4 Sessions, 141 Papers, 0 Presentations
Conference: International Conference on Mechanical Engineering, Measurement Control, and Instrumentation (MEMCI 2021) 2021
Volume Number: 11930

Table of Contents

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Table of Contents

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  • Front Matter: Volume 11930
  • Electronic Imaging and Opto-mechanical Design
  • Sensing Technology and Measurement Control Applications
  • Intelligent Instrumentation and Automation Equipment
Front Matter: Volume 11930
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Front Matter: Volume 11930
This PDF file contains the front matter associated with the SPIE Proceedings Volume 11930, including the Title Page, Copyright information and Table of Contents
Electronic Imaging and Opto-mechanical Design
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Maintenance method of large machine tool ball screw wear based on brush plating technology and precision grinding technology
Ke Mei, Bo Peng, Jingjing Di, et al.
Due to the large length, difficult clamping, as well as dimensional accuracy and coaxial accuracy are difficult to restore, the maintenance of large machine tool ball screw wear has always been a difficult problem in machine tool maintenance. In this paper, according to a large machine tool ball screw bearing wear fault, the specific maintenance scheme is put forward through fault analysis. Based on brush plating technology and precision grinding technology, using the lathe with spindle through-hole, a special tooling suitable for large-scale ball screw maintenance is designed. Finally, we proposed a comprehensive maintenance method for large machine tool ball screw wear fault, which achieved a good maintenance effect, and can provide reference for the maintenance of large machine tool parts.
Experimental study on axial bending force of elevator wire rope
Hui Chen, Aihua Jiang
"Elevator balance coefficient steel wire rope tension detection method" is a no-load test method of elevator balance coefficient. The “BCD” device designed and manufactured according to this test method has the characteristics of convenience, quickness and high detection accuracy. In order to clarify the design requirements of this method on the testing equipment, this paper studies the influence of the diameter, length and bending degree of the wire rope on the bending reaction force in the testing process. In this paper, the elevator traction wire rope samples with three diameters of 10mm, 13mm and 16mm, 15, 20, 25, 30 and 40 times the diameter length, are selected respectively. Two groups of axial bending tests were carried out on the samples by using a pressure testing machine. The test results show that: 1. The installation distance of the upper and lower clamping device should be greater than 20 times of the diameter of the measured wire rope; 2. The lifting distance of the lifting device can be more than 5mm to obtain relatively stable test results; 3. The tension obtained from the steel wire rope group cannot be equivalent to the hanging mass of the steel wire rope group, and can only be used as the equivalent mass to calculate the elevator balance coefficient; 4.The testing equipment shall be calibrated separately for each wire rope diameter.
Research on fuzzy security evaluation of power battery system with thermal runaway test by GRA and entropy method
Yuanmao Li, Guixiong Liu, Yu Zhang
In order to evaluate the safety level of power battery system with thermal runaway test comprehensively and objectively, the gray correlation analysis method, entropy weight method and fuzzy theory are used to study the safety level of power battery system thermal runaway testing. By analyzing the key factors that affect the safety level of the thermal runaway test of the power battery system, the weight of different factors is considered based on the thermal runaway simulation test data of the power battery system. The grey relational analysis (GRA) and entropy weight method are used to determine the weight of the influence of different factors on the result of thermal runaway. Finally, by constructing the membership matrix, the fuzzy evaluation model is used to classify the safety of the thermal runaway test of the power battery system. The results show that the rating results of this method are consistent with the simulation test results of thermal runaway of the power battery system.
Modeling and stability analysis of power system with SVC considering harmonic coupling characteristics
Runsheng Xie, Guorong Zhang, Chunpeng Wang
Aiming at the problems of power quality deterioration and low frequency oscillation in power system caused by the large-scale application of static var compensator (SVC), the existing methods ignore the dynamic coupling characteristics among harmonics in SVC and directly equate SVC to a fundamental frequency linearization model. This assumption fails to reflect the difference of equipment dynamic characteristics with frequency variation. Therefore, a harmonic interaction analysis method between SVC and power grid based on harmonic transfer function matrix is proposed in this paper. The dynamic harmonic domain (DHD) theory is used to construct the whole model of the system with SVC considering the influence of conduction angle and phase-locked loop module, and the corresponding harmonic transfer function matrix of the system is derived from the closed-loop model. Based on the harmonic dynamic transfer function matrix, the eigenvalue method is used to analyze the influence of controller parameters on system stability and to predict the oscillation frequency. MATLAB/Simulink simulation results demonstrate the accuracy of the system DHD model and the correctness of the system stability analysis.
Probabilistic assessment of transformer operating risk considering the correlation among wind power, PV and load
Xiang Lin, Jian Fang, Hongbin Wang, et al.
In order to evaluate the impact of wind farm and photovoltaic (PV) power station on the operation risk of output transformer, the joint probability density distribution of wind power and load, PV and load as well as wind power, PV and load are established by Copula theory. Based on Susa model, the probability density distribution of characteristic temperature of transformers is derived. For the assessment of the operational risk of transformer, this paper constructs IDP, IFP, ELOIL indexes. Finally, a sending grid with renewable energy base is taken as an example. of which the relevant risk assessment indexes are analysed to verify the accuracy of the proposed method. Moreover, the results can provide guidance for the selection and operation of transformers.
The optimal method of distributed power grid connection considering demand-side participation
Minglei Jiang, Yuting Bao, Qunying Li, et al.
The volatility of wind and photovoltaic power generation increases the difficulty of the grid to absorb renewable energy. To solve this problem, the demand side price response participation is introduced, and the hierarchical optimization method is used to study the distribution network configuration with distributed generation. At the planning level, the economic and network loss effects are considered to determine the demand side grid regulation load capacity and the installation location of distributed generation. Based on the planning scheme, the operation layer considers two modes: the controlled participation of the grid control load and the active participation of the price incentive load, and evaluates the economic operation, renewable energy utilization rate, voltage stability, and peak cut of different participation degree operation schemes. To improve the solution efficiency of the hierarchical optimization and maintain the diversity of the solution set, a particle swarm algorithm based on simulated annealing is used for calculation. Finally, the rationality and effectiveness of the proposed method are verified by the simulation analysis of an actual distribution system in Northeast China.
Development of engineering structure intelligent monitoring system based on LoRa
Tingdong Ye, Yan Ai, Lingxin Shi
According to the real-time and accurate monitoring requirements of the engineering structure, an intelligent monitoring system based on Lora is developed. The system constructs the underlying wireless monitoring network through Lora communication technology. The wireless monitoring node realizes the plug and play of sensitive sensing elements and weak signal detection through WTIM (Wireless Transducer Interface Module, WTIM) module and NCAP (Network Capable Application Processor, NCAP) module. Based on Lora sensing network, the multi sensor cooperative monitoring is realized by the collaborative cognitive order parameter network model; the network intelligent monitoring system platform is developed by using JSP and SQL Server2016 relational database based on the C/S model. The experimental results show that the strain detection error can reach 0.1%, vibration detection error is 5%, and the intelligent network monitoring is realized.
Damage monitoring experiment on diagonal pressure pipe based on distributing optical fiber
Xingsheng Lao, Xian Gong, Yong Liu, et al.
Aiming at the prefabricated damage of the elbow of the polygonal pressure pipe, a test system was established based on the distributed optical fiber sensor and the damage monitoring test under the high temperature pressure flow condition, the high temperature normal pressure condition and the normal temperature pressure condition was carried out. The broadband vibration noise of the fluid conveying pipeline under high temperature flow conditions is much higher than the strain noise level measured by the optical fiber sensor, and the strain change characteristics are difficult to distinguish; under the high temperature and normal pressure conditions, the impact range of the circular strain of the damage is small, and the measurement path Damage can be monitored within the damage range; the strain curve of the axial measurement section is messy under normal temperature and pressure conditions, and there is no obvious damage feature. Obvious strain peaks can be seen in the circumferential measurement section, and the damage location accuracy is less than 0.1m. The results show that the distributed optical fiber sensor has obvious characteristics of damage in the axial temperature load measurement, and the damage characteristics of the internal pressure load in the circumferential measurement. The decoupling processing can realize the high temperature and high pressure linear pipeline damage monitoring.
Model investigation of a tidal current turbine for rivers
Lin Li, Xueshi Yao II, Tiantian Feng III, et al.
The hydraulic resources of the rivers tidal current need to be developed urgently in China. To solve the problem of low efficiency of tidal turbines, a multichannel diversion crossflow hydroturbine is designed with simple structure, high reliability, little environmental impact and high security. This new type of turbine included: the water guide device of the multichannel diversion, crossflow turbine with no center shaft, the long and short blades interval setting etc. The strength and vibration models of the crossflow turbine are made by finite element method. The hydrodynamic performance can be improved by increasing the turbine’s flow space, and simultaneously improving efficiency. The turbine has a broad market prospect, and the economic and social benefits are very remarkable.
Failures originated from defects of IGBTs used for electrical power application
Jinyuan Li, Pengfei Wu, Gaoming Shi, et al.
As high-power semiconductor devices, IGBTs are widely used in electrical power application, the reliability of which have been paid attention by both manufacturers and end users. The defects of IGBTs on the hierarchy of die, which could be originated from wafer manufacturing and packaging process, may cause failure during testing and normal working conditions. Herein, typical failure analysis cases based on systematic procedures were chosen to illustrate the reason underneath, revealing defects of IGBTs die, such as micro-cracks in dielectric layer may originated from deposition process, and mechanical damage in passivation layer probably due to crimping process, could result in failures of IGBTs that weaken the reliability, which should be avoided during the fabrication via strict quality control.
Dynamic simulation analysis of boom falling accident of portal crane
Min Chen, Shan He
In order to analyze the damage degree of the Boom of portal crane when the Boom crashes at different range, the finite element dynamic analysis method is used to simulate the accident of the Boom crashing at different positions. The results show that the maximum stress, serious structural deformation and even breakage occur when the Boom crashes at the smallest range.
Safety performance analysis of container gantry crane lifting leg
Aihua Jiang, Xinhua Wang, Shan He, et al.
The purpose of heightening and upgrading the portal leg of container gantry crane is to improve the stacking height of goods and the stacking quantity of goods. Based on the finite element modeling, this paper analyzes the structural strength and stiffness safety performance under three working conditions, and checks the structural stability, which provides a new idea for the overall safety performance research of related equipment after heightening and upgrading.
Research on kinematic characteristics of flexible bearing for harmonic reducer
Yipeng Chen, Yazhen Wang, Zhijie Lin, et al.
As a high-precision reducer used in industrial robots, the performance of harmonic reducer has a great influence on the accuracy of the entire mechanism. Flexible bearing is forced to deform to ellipse after assembly wave generator, which makes its motion track different from ordinary bearing. Based on the kinematics and geometry principle, the kinematics characteristics of the flexible bearing are studied and the motion track of the rolling element center of the flexible bearing is analyzed. The result shows that it is not a standard ellipse. Then, the relative motion between the bearing pitch ellipse and nodal cage is calculated. Finally, based on the velocity distribution model of the flexible bearing, the motion velocity of the cage is analyzed, and the general expression of the angular velocity of the cage is obtained. The results have guiding significance for the design and optimization of flexible bearing.
Design and test of hand-carried air-assisted electrostatic sprayer
Nengchao Li, Zhen Li, Xin Ai, et al.
The traditional hand-carried boom sprayer has a large spray volume and a small working range, while the traditional air-assisted sprayer has uneven droplet distribution. In response to these problems, this research designed a hand-carried air-assisted electrostatic sprayer, which are charged by direct contact charging method. In order to explore the spray performance of a hand-carried air-assisted electrostatic sprayer, and to clarify the effect of different parameters on the performance of the sprayer, a spray test platform was set up. The test factors were based on spray pressure, spray distance and charging voltage, and the charge characteristics, droplet size and deposition characteristics were tested by the droplet mass-charge ratio, the average diameter and the spray coverage. The experimental results show that: The droplet charge-mass ratio increases with the increase of the charging voltage. When charging voltage is greater than 7kV, the sprayer has the best charging effect when the spray pressure is 0.4MPa; Electricity can improve the atomization performance, but it will increase the droplet relative span, so the charging voltage should not be too large; Electricity and air-assisted improve the spray performance, the spray efficiency is increased by 32.6%, and the water is saved by 23.3%.
Design of image acquisition system of online verification device for ship engine spare parts packing
Chunhua Zang, Jiajun Song, Taowen Chen, et al.
Ship engine spare parts are very important. The manual inspection method for spare parts preparation is highly subjective, and there may be problems such as missed installation, multiple installations, and wrong installations. This paper designed an image acquisition system for deep learning target detection of ship engine spare parts, which could stably collect spare parts images suitable for deep learning target detection. Firstly, it analyzed the problems in the acquisition of ship engine spare parts verification images, and pointed out the problems of perspective artifacts and low CNN feature mapping output response; secondly, it designed a base plate that could avoid perspective artifacts and improve the response of the convolutional neural network. It proposed 4 spare parts placement rules, including Centered placement rule, Feature face up rule, Long side horizontal rule, and Left center of gravity rule. It reduced the number of samples of each type of spare parts used to train the deep learning target detection network from 216 to 3. The experimental results showed that the average accuracy of the Mask R-CNN model for detecting ship engine spare parts was 96.8%, and the detection time did not exceed 0.11s, which met the online verification requirements of the spare parts packing process.
A multitask-based flexible networking and resource scheduling algorithm for UAV swarm
Yongguang Liu
At present, the related research on UAV swarm resource scheduling pays attention to static mathematical modeling but can not adapt to the dynamic application, and pays attention to the assignment of tasks without considering the influencing factors of the network. This restricts the application of these studies in practice. In view of these problems, this paper proposes a resource scheduling algorithm for flexible networking, which establishes a UAV scheduling mechanism and a flexible networking strategy based on task requirements. The resource scheduling decision node is selected by betweeness centrality computing based on network topology. The simulation shows that the algorithm can flexibly schedule resources between task colonies according to demand, and effectively improve the utilization rate of resources.
Super-resolution reconstruction method of transmission line key components image based on SRGAN
Haixia Ma, Zhongxing Li, Na Shen, et al.
Aiming at the problem of unmanned aerial vehicle inspection images being susceptible to environmental interference during shooting, resulting in blurry image capture and inability to accurately identify defects in key components of transmission lines, this paper uses SRGAN to super-resolution reconstruction of low-resolution inspection images to improve image quality to meet the needs of deep learning algorithms or manual accurate recognition of line defects. First, a high-resolution image data set of key components of the transmission line is produced, and the data set is obscured as a low-resolution image data set. Then the PaddlePaddle framework is used to build the SRGAN super-resolution network model to perform super-resolution reconstruction on the low-resolution data. In model training, the model parameters are optimized according to the training situation, the optimal model is obtained, and the reconstruction experiment on low-resolution images is performed. The experimental results show that the image generated by SRGAN is similar to the high-resolution image in sharpness, and has achieved good results.
Remaining useful life prediction of bearing based on autoencoder-LSTM
Chengwang Guo, Yaohua Deng, Chunfeng Zhang, et al.
Bearings are the key components of injection molding machines. It is of great significance to accurately assess the degradation of bearings in operation and predict their remaining useful life. With the rapid development of modern industry and the increasing complexity of equipment, model-based methods are difficult to adapt to changing environments, and data-driven methods have been extensively developed. This paper proposes an Autoencoder-LSTM remaining useful life prediction method, which uses Autoencoder to extract features from the original bearing data, and uses LSTM to realize the life prediction of the bearing. Experiments on the PU dataset verify the effectiveness of the features extracted by this method, and compare with other methods to prove the superiority of the method; then the life prediction experiment on the XJTU dataset verifies that the method has higher prediction accuracy, which is better than traditional machine learning and related methods.
Commutation failure suppression strategy of HVDC transmission system based on deep double Q-Network
Haidong Huang, Xindong Li, Xiaofan Hou, et al.
In the case of AC system fault at the inverter side of HVDC transmission system, commutation failure will occur when the turn-off angle of the inverter is less than the limit turn-off angle. To solve the problem of commutation failure, this paper presents a commutation failure suppression strategy of HVDC transmission system based on Deep Double Q-Network (DDQN). A reinforcement learning algorithm with double neural network structure is adopted to accurately predict the DC current value at the inverter side, thus improving the commutation failure prevention and control module (CFPREV), reducing the trigger delay angle at the inverter side and dynamically adjusting the constant current reference value at the rectifier side based on predicted value. At last, the experimental results show that this strategy can effectively suppress commutation failure of HVDC transmission system.
Research on the influence of moisture immersion on the electric field distribution of composite insulator with interface defects
Xinming Ma, Yifan Fu, Hao Shen, et al.
Composite insulators have been widely used in power system. However, in practical application, they may have some faults, such as decay-like fracture and flashover of internal defects. In order to study the influence of the interface defects and moisture immersion on the electric field distribution characteristics, the 3D model of the 500kV composite insulator and its internal defects were established. The finite element analysis software COMSOL was used to calculate the electric field distribution by changing the length, span, thickness and tip curvature radius of the defect. The results show that the presence of air gaps and water gaps will significantly increase the local electric field strength. The maximum field strength is positively correlated with the span and thickness of the defects, and negatively correlated with the length. The tip curvature radius of the defects has no obvious effect on the air gap, but there is a point effect in the water gap.
Research on multi-exposure image fusion algorithm based on detail enhancement
Yanhua Peng, Biao Feng, Yipu Yan, et al.
Machine vision detection relies on high-quality image extraction features obtained by the camera, and multi-exposure image fusion technology is a crucial method to acquire images with high dynamic range and rich details. In order to better obtain high dynamic range detail information of the entire scene to extract more image features, this paper proposes a detail enhancement multi-exposure image fusion algorithm based on the exposure function and the homomorphic filtering function to determine the weight. First, image sequences with different exposures are acquired by the camera and corrected, then the exposure function and homomorphic filtering are used to determine the weight map of each image, and finally the final fusion image is obtained by the multi-scale method. Compared with the current four advanced methods, the experimental results show that the algorithm can obtain better imaging quality and more image detail information, and obtain satisfactory visual effects. It provides a solution for the subsequent machine vision to extract richer features of the image.
Research on estimation method of starting voltage of power battery in high power laser system
Yahui Ren, Yong Tong, Rui Wang, et al.
Power battery is the energy source of high power laser system. The starting voltage is the key index to judge the working state of power battery. In order to estimate the power battery voltage and optimize the power supply control effect of high power laser system, based on the measured data of power cell, the least square method was used to fit the internal resistance curve, and the expression of the starting voltage of the power battery was deduced, which was applied to the evaluation test of the energy storage battery in the high power laser system. The application results show that the accuracy of starting voltage estimation of a certain type of lithium titanate power battery can reach more than 95%, which effectively meets the demand of system power supply control. The function fitting and the method of power battery starting voltage derivation developed in this paper are universal and provide a reference for the starting voltage estimation of other types of battery cells and other related application conditions.
Applications of NSST enhancement based on adaptive longicorn optimized segmentation and improved modulus in infrared image of electrical equipment
Xin Zhang, Qiang Yao, Xiaohua Zhang, et al.
The normal state of power equipment is directly related to the operation of the system. At present, the most widely used method is to use infrared image to implement real-time monitoring of the operation status of power equipment. In order to solve the problems of noise, blur and low contrast in infrared detection, an infrared image NSST enhancement algorithm based on adaptive segmentation and improved fuzzy enhancement is designed in this paper. The original infrared image is transformed into high-frequency and low-frequency components in NSST domain. Then, the high-frequency component with noise is denoised by the spatial adaptive noise smoothing algorithm, and the improved fuzzy enhancement is used.The low-frequency component with the main body of power equipment is segmented into background and foreground parts by adaptive Longhorn, and then enhanced separately. Finally, the enhanced high-frequency and low-frequency components are inversely transformed by NSST to form the final enhanced image. Compared with the other three traditional algorithms, this algorithm has the advantages: it can not only filter the infrared image noise of power equipment effectively, but also improve the infrared image contrast, making the infrared image conform to the human visual effect, and it is easier for the human eye to recognize the fault. It is very helpful to detect and locate the thermal fault of power equipment.
Infrared image enhancement algorithm based on seagull optimized Otsu and BEEPS algorithm in NSST domain
Zhang Xin, Yang Yu, Yike Shi, et al.
Aiming at the problems of fuzzy, noisy, and low contrast of infrared images in detection of power equipment. This paper designs an improved Otsu segmentation threshold based on seagull optimization and BEEPS filter algorithm in NSST domain. First, the original infrared image is decomposed by NSST to high and low frequency components. Low-frequency component is divided into two parts, the foreground and background, and the enhancement processing is performed separately to each part. BEEPS algorithm is used in this paper for high-frequency component processing. Finally, the processed low-frequency components and high-frequency components are subjected to NSST inverse transformation to obtain the final enhanced image. The algorithm in this paper is compared with the other three algorithms to verify its superiority: it has improved the accuracy of infrared image threshold segmentation and strengthened the depth of field, and increase the brightness of power equipment. The overall contrast of the image is enhanced and the noise part is also effectively filtered out, improving the overall visual effect of the image which is conducive to use thermal effects to determine the operating status of power equipment and the detection and fault location of thermal fault detection.
Infrared image of electrical equipment enhancement using grey wolf adaptive nonlocal mean denoising and adaptive fuzzy enhancement
Xin Zhang, Xikui Sheng, Chunsheng Li, et al.
In this paper, the infrared image of power equipment contains noise, blur and so on, which makes it impossible to accurately judge and locate the infrared fault. An infrared image enhancement algorithm based on grey wolf adaptive non local mean denoising and adaptive fuzzy enhancement is proposed. Firstly, grey wolf adaptive non local mean denoising is used to denoise the initial infrared image, and then NSCT transform is performed. After the transform, grey wolf algorithm is used to optimize the fuzzy parameters of high-frequency components, and then enhancement is performed; the low frequency component is linearly enhanced. Then the NSCT inverse transform is performed. After the algorithm verification, it is shown that the algorithm is effective in infrared image denoising and enhancement, and the evaluation index also verifies the effectiveness of the algorithm.
The field-circuit coupled physical simulation of open boundary electric field
Li Zhang, Qing Chen, Hongbin Li, et al.
The solution of open boundary electric field is a common problem in the electrical field, and the treatment of the open boundary condition is one of the difficulties. In this paper, a physical simulation method of open boundary electric field based on field-circuit coupling is introduced. The near field of open boundary electric field is retained, and the far field is equivalent to a resistance network. The scattered compensation electrodes are placed on the interface to maintain the interface potential condition and realize the coupling of electric field and circuit. The resistance calculation and the optimal design of compensation electrodes are completed by means of electromagnetic numerical calculation software. The correctness of this method and the effectiveness of simulating open boundary electric field are verified by experiments.
Fault section identification of distribution network based on zero sequence current distribution characteristics
Yirong Su, Weiwei Zhang, Huamin Liang, et al.
For single-phase earth fault of small current grounding system, a new method based on zero sequence current distribution is proposed to accurately identify the fault section of single terminal radial distribution network. The zero-sequence equivalent circuit model of the small current grounding system is established to analyze the distribution characteristics of zero-sequence current between the fault-line and the fault-line in the case of single-phase grounding fault, and the identification criterion of fault section is constructed according to the difference of the amplitude of zero-sequence current between the upstream and downstream of the fault point. Using distributed fault indicator installed along the line, the amplitude of fault zero sequence current is obtained synchronously. The fault line segments are identified and the fault points are located between the two fault indicators by clustering the data hierarchy in the data object matrix. In PSCAD/EMTDC, a 10kV small current grounding system model is built to verify the accuracy and reliability of the proposed method. Simulation results show that the proposed fault zone identification method is not affected by fault resistance, fault initial phase Angle and fault location.
Thermoelectric structural field coupling simulation of ideal electrical contact model
Yu Feng, Kai Wu, Shaolei Wu, et al.
At the micro level, the contact between the two surfaces is the mutual contact and extrusion of between innumerable tiny convex points. And the contact of these convex point in the electrical connection will cause the current to tighten, thus producing contraction resistance. In this paper, a simple and intuitive spherical conductor contact model was established by ANSYS Workbench software to conduct electro-thermal coupling and statics analysis of contact models and explore the relationship between current intensity, contact area temperature, and contact pressure at the micro level.
Comprehensive optimization method of short-circuit current restriction measures considering safety efficiency and cost
Daojun Chen, Yongyan Liu, Wangwei Gan, et al.
To solve the problems such as the increasingly close structure of the 500kV/220kV electromagnetic loop network and the high level of short-circuit current in power system, it is of great significance to study a practical and economic comprehensive optimization method for limiting short-circuit current. In this article, a comprehensive optimization method of short-circuit current limiting measures is proposed considering the safety efficiency cost of current limiting measures. Firstly, a dimensionality reduction strategy considering the sensitivity of current limiting measures is proposed. And then a comprehensive optimal allocation model of current limiting measures considering system stability, current limiting effect and investment cost is established. Finally, the order optimization algorithm is used to solve the model. The accuracy and effectiveness of the proposed method are verified by an actual power grid in a province of China.
The research and implementation of intelligent power management system based on MCU
Zerui Chen, Guoguang Zhang, Rui Wang, et al.
Power management is important for a mobile system relying on battery power, to achieve the efficient use of the power supply modules and intelligent monitoring. In this paper, some efficient LDO and switching powers are selected and high- performance STM32H743 chip are used to perform different power-on sequences. In addition, the relevant power supply parameters are monitored and controlled by using relays, voltage and current sensors. The test results show that the system has the characteristics of low heat dissipation, low power consumption, high security, long battery life and high reliability. This system effectively solves the backward comprehensive performance index and weak universality of the traditional power supply combination.
Numerical simulation method for wrinkle defect of automobile panel
Jinwu Wang, Wenjun Lv, Ouyang Yi, et al.
In recent years, with the extensive use of high strength steel sheet metals in automobile production, the wrinkle resistance of sheet metal, that is, the ability to resist the appearance and development of surface defects, which has been paid increasing attention. The wrinkle in the stamping process may not only cause a large number of waste products, but also easy to scratch the mould. Even if the wrinkle is flattened in the late stamping period, it will leave traces on the surface of the product, affecting the appearance of coating and stamping parts. Although the application of stamping simulation can also predict the wrinkle in the stamping process more accurately, there are few research results on the mechanism of wrinkle occurrence, material property parameters, the influence of stamping die and its process on wrinkle, and the effective control method of wrinkle, which can’t meet the needs of engineering practice. For the last few years, the authors have studied the non-uniform wrinkling process by using the combination of finite element and experiment, in order to master the wrinkling of sheet metals under the non-uniform stretching, determine the critical wrinkling index, and evaluate the anti-wrinkling performance of sheet metals.
Study on nitriding enhancement technology of lifts safety gear wedge
Xiaoping Huang, Lin Chen
Safety gear is the key safety protection device in the elevator. When the elevator falls out of control, it can stop the elevator. The wedge of safety gear is its core component, but found in the actual work, the wedge is seriously worn and the wear resistance is reduced after linkage test, which can not guarantee the reliability in real action. In order to effectively solve this problem, this paper proposes to use nitriding technology, a diffusion layer is formed on the surface of the safety gear wedge, so as to improve the wear resistance and strength of the wedge. This technology can improve the strength performance of safety gear without changing the wedge size, so it has a good application prospect.
Analysis of driving safety factors in urban tunnels based on ergonomics
Jingkang Huang, Zhen Cao
Urban tunnel, to a certain extent, can relieve the pressure of urban traffic, and at the same time, it has the advantages of using underground space effectively and not destroying the ground landscape. However, there are traffic congestion and frequent traffic accidents in urban tunnels, so it is necessary to study the traffic safety of urban tunnels. According to th e statistical analysis of the accident, the driver of improper driving behavior is the main cause of the accident, the study of driving behavior will help improve the driving safety. Therefore, as the research object, based on the urban tunnel using human-computer ergonomics theory, the design, the real vehicle experiment to explore the state of traffic flow, speed, intensity of illumination and the influence of tunnel length factors for driving. The research results can provide guidance for urban road traffic management departments and traffic participants, and have certain reference significance for relevant regulations and regulations in traffic control, so as to reduce the occurrence of traffic accidents in urban tunnels.
Application of finite element analysis in local stability check of main girder of bridge crane
Shan He, Min Chen
Local stability is an important parameter of bearing capacity of bridge crane structure. The calculation method for the local stability of the main beam is specified in detail in gb3811-2008, but the calculation formula needs to know the stress magnitude of the web edge of the main beam. The traditional calculation method is complicated and time-consuming, which generally requires 2-3 working days, and is not accurate. The finite element analysis can obtain the stress distribution cloud map of the structure, and the direct extraction of the stress value from the finite element analysis results for the local stability check of the main beam can be completed within half a working day, and the calculation accuracy is improved.
Relay protection communication model based on 2M optical interface
Weixing Gu, Zhiruo Meng, Tingting Wang, et al.
Currently, most areas of the State Grid are still using a large number of multiplexed 2 M optical fiber channels using photoelectric conversion equipment to transmit relay protection signals. After a long period of use and exploration, this technology is already a relatively mature solution, but it also has some shortcomings, such as complex photoelectric conversion links, large-scale communication equipment in the early stage, and lack of direct communication between relay protection devices and optical transmission equipment. By studying the SDH E1 mapping path, this article refers to the ITU-T standard to analyze the feasibility of the direct interconnection between the relay protection device and the 2M optical interface of the optical transmission equipment. By eliminating the photoelectric conversion equipment, the relay protection equipment and the optical transmission equipment are directly interconnected. In response to the "one specialization and three complex" requirements of the State Grid, a business model based on 2M optical interfaces was proposed. After analyzing and comparing the communication delay with the original business model, it is found that the delay of the business model based on the 2M optical interface has been significantly improved.
Study on influence of reinforcement ring clearance on strength and stiffness performance of expansion joint
Bing liang Luo, Yun Wang, Tong Xuan Zou, et al.
In order to deal with the complex working conditions of high temperature and high pressure and improve the bearing capacity of expansion joint, the reinforced bellows expansion joint with reinforcing ring is often used in engineering. At present, most of the studies on the strength performance of the reinforced bellows expansion joint do not consider the influence of the assembly gap between the reinforcing ring and the bellows on the strength performance of the expansion joint, and ignore the thermal stress caused by the temperature difference between the inner and outer surfaces of the bellows under high temperature conditions. In this paper, the effect of the gap between the stiffeners and bellows on the high temperature strength of the expansion joint was studied by full thermodynamic coupling numerical analysis method. The maximum Mises stress of the expansion joint with the gap between the stiffeners and bellows under different temperature differences was obtained. The strength performance of the expansion joint can be effectively improved by selecting the optimal clearance between the stiffening ring and the bellows, and due to the different temperature difference between the inner and outer surfaces of the bellows, the clearance value of the stiffening ring is different. The conclusion provides reference for the theoretical research, optimization design and manufacture of the reinforced bellows expansion joint under high temperature and high pressure conditions.
Research on DC resonance mechanism and suppression measures of modular multilevel DC ice melting device
Guihang Yan, Jikang Wang, Hui Huang, et al.
DC ice melting is one of the effective measures for the power grid to resist low-temperature freezing disasters. The operational reliability of the DC ice melting device during the icing of the line is extremely important. This paper briefly introduces the topology and principle of the full-bridge modular multi-level DC ice melting device, and introduces the DC side oscillation phenomenon under the working state of the modular multi-level DC ice melting device. Next, This paper analyze the cause of resonance and take measures to suppress resonance. That is, measures such as shortening the delay of the DC ice melting device control system, optimizing the design of control parameters, and using nonlinear filters to process the feed forward voltage to suppress high-frequency resonance. The simulation results show that the phase frequency characteristics of the impedance of the DC ice melting system based on the modular multilevel convertor (MMC) topology have been greatly improved. The ice melting device can be unlocked and boosted normally, which proves the effectiveness of the optimized suppression measures and greatly reduces the risk of high-frequency resonance.
Zero voltage ride through state judgement method for renewable power generation system based on terminal current
Chong Shao, Zhangpeng Zhou, Yunsong Yan, et al.
As the “Double Carbon Goal” proposed in China, the renewable power generation system (RPGS) will further enhance the position in the grid. The construction of a panoramic monitoring system (PMS) for renewable power plants can better perceive the operating status of the unit. The existing grid-connected guidelines for photovoltaic (PV) systems require PV power stations to achieve 150ms on-grid operation when the voltage at the grid-connected point drops to zero. In addition, the need for zero voltage ride through (ZVRT) will also be proposed for the grid connection of future wind farms. However, when the grid-connection point voltage is zero, the active and reactive power of the generator terminal are both zero at this time. At present, the unit status detection mostly uses active/reactive power judgment, so it will misjudge the unit state in the ZVRT and offline state respectively, which will cause the fault expansion. In this paper, a method of using terminal current as state judgment is proposed by considering the ZVRT method. The ZVRT characteristics for RPGS are simulated by using MATLAB/Simulink to verify the proposed judgment method. The results show that state determine for RPGS by using the terminal current can improve the reliability of the panoramic monitoring system.
Study on overvoltage characteristics of lightning intrusion wave in 500kV GIS substation
Chonghao Fang, Zhe Chen, Pengfei Li, et al.
High amplitude and high steepness overvoltage caused by lightning intrusion wave in substation is an important factor threatening the insulation of equipment in the station. The characteristics of lightning overvoltage in a 500kV GIS substation of a nuclear power plant are analyzed in this paper. EMTP-RV software was used to build the model of transmission line and substation system, and the difference of lightning overvoltage characteristics of GIS power station under different lightning strike conditions was simulated and analyzed. The influence of arrester on the over-voltage characteristics of each equipment node in the station is compared. The results show that: Under the two conditions of lightning backflash flashover and shielding failure without flashover in the near area of the line, the invasion overvoltage is the most serious, and the arrester has an obvious effect on the suppression of lightning overvoltage.
Research on debugging technology and safety management of relay protection device
Dongfu Li, Shengzhu Li, Yang Gao
With the rapid development of power industry and the continuous progress of science and technology, relay protection technology has also entered the industry of intelligent development. The continuous development of relay protection technology effectively improves the power supply stability of power system, but at the same time, it also puts forward new issues for relay protection workers. In the actual operation management process, it is required to form a different debugging and management scheme with the corresponding relay protection device, and regularly check its operation status, so as to achieve the concept of fault detection and timely treatment. And ensure the normal operation of the power system relay protection device, so as to improve the stability of the safe operation of the power grid. This paper will carry out the research on the debugging technology and safety management of relay protection devices in the current power system in China, in order to improve the operation safety of power system protection devices.
Design of small corn peeling harvester
Mingming Liu, Ruichao Zhang, Kai Xia, et al.
Aiming at mountainous and hilly areas where hand picking and peeling is still the main task, in order to reduce the problem of hand harvesting in hilly and mountainous areas, combined with the existing corn harvesting technology, a small corn peeling harvester suitable for mountainous and hilly areas is designed. The main body of the design is to design the peeling roller, the picking roller, the press roller and the reel bat. Experiments show that the peeling rate of the small corn peeling harvester designed by this method is more than 90 %, which can effectively improve the harvesting speed of corn and reduce the harvesting loss rate of corn. It can effectively peel the harvested corn, and provide certain application reference for solving the peeling of corn.
Sensing Technology and Measurement Control Applications
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Research on damage identification of highway bridge
Hanbing Wang, Yunkai Zhang, Guohua Li
This paper summarizes the current highway bridge damage detection methods, and draws the following conclusions: 1. Traditional static reaction and dynamic characteristic recognition methods can more accurately identify the damage position of the bridge, but it is more sensitive to the environment impact, and the confidence of the recognition in the complex environment needs to be improved. 2. The bridge damage identification method based on wavelet analysis is more adaptable to the environment, but this method is mainly used for bridge damage identification with bridge local structure and simple structure, and its universality needs to be further improved. 3. The bridge damage recognition method based on artificial neural network can be combined with big data to form a highly intelligent system. However, it is difficult to identify special structural bridge damage with insufficient data samples. 4. The indirect method research of bridge damage identification has the advantages of high efficiency, strong flexibility and cost saving. Therefore, it has the engineering value of the broad application prospect. The author puts forward the outlook based on the above conclusions.
Research on the Influence of slope and heat release rate on the critical velocity of straddle monorail tunnel
Jiehang Deng, Yanqiu Chen, Peng Wang
Straddle monorail tunnel are mainly used in urban rail transit with the characteristics of larger structural section, larger slope, and higher heat release rate than subway tunnel. In order to study the influence of slope and heat release rate on smoke movement of critical velocity of longitudinal ventilation tunnel, different slope (-6%, -3%, 0%, 3%, 6%) and different heat release rate (5 MW, 10 MW, 20MW, 50MW) are studied in this paper based on the 1/20 straddle monorail tunnel model. The result shows that the slope of the tunnel and the heat release rate of fire are the main influencing factors. Firstly, compared with 0% critical velocity, the critical velocity of uphill air supply is greater and that of downhill air supply is smaller. Secondly the critical velocity of downhill air supply changes very little when the heat release rate and slope are large enough. Besides, critical velocity of the uphill air supply has a linear relationship with the slope, while that of the downhill air supply has an inverse proportional relationship with the slope. Finally, the critical velocity factor based on experimental data is proposed at the end of the paper.
The design experiment and simulation of parallelogram micro-low gravity balance device with adjustable spring
Shujiang Wu, Ming Gao, Song Yin, et al.
Low-gravity passive balance technology is widely used in astronaut adaptive training. Among them, the series-spring parallelogram mechanism is a basic mechanism in the passive balancing device. We propose a adjustable spring parallelogram device. Compared with the previous devices, it is easy to adjust and can realize the balance of gravity according to different situations. Theoretical analysis is utilized to design this parallelogram mechanism with parallel springs in series, then both the different weight balance experiments and numerical simulation of impact load in ADAMS verify that the mechanism has the characteristics of low gravity balance. This provides a theoretical basis and application basis for the design of adaptive training devices for astronauts on the ground.
Signal transmission method of wireless ad hoc network in complex cable channel environment
Yubing Duan, Pengfei Li, Hao Zhang, et al.
In order to reduce the signal transmission interference in the complex cable channel environment, a signal transmission method in the complex cable channel environment is proposed by selecting the optimal signal transmission location. Through analyzing the signal model of right angle bending channel, the equivalent resistance, equivalent inductance and equivalent capacitance of the cable are calculated, and the transmission and attenuation characteristics of the communication signals in the cable are analyzed, the distribution parameter model of the cable circuit is established, so that the cable parameters are evenly distributed and the electromagnetic signal interference is reduced. The test results show that the method in this paper can guarantee the communication rate of nodes in practical applications and shorten the communication time.
Research on positioning method of reinforcement in reinforced concrete based on magnetic induction detection
Zongyi Luo, Jing Yu, Chunyi Lu, et al.
The orientation of steel bars is an important basis for steel bar detection in reinforced concrete. Based on the magnetic induction detection method, this paper proposes a method of locating the reinforcement in concrete. Firstly, the model of steel bar positioning is built according to the actual reinforced concrete structure, and the magnetic induction detection method is studied. Aiming at the long-distance main reinforcement positioning detection similar to the whole tower, a new method of orientation of single magnetic field excitation device is proposed. A new method of orientation of the local main reinforcement is proposed. Finally, the simulation and verification are carried out according to the actual model of steel structure size in the tower.
Analysis of dynamic characteristics of parallelogram institution with series springs under impact load based on Adams
Shujiang Wu, Ming Gao, Qinzheng Li, et al.
Low-gravity passive balance technology is a technology widely used in astronaut adaptive training. Among them, the series spring parallelogram institution is a basic institution in the passive balancing device. A parallelogram institution with series springs is studied in this paper. Firstly, the three-dimensional parallelogram institution model of the series spring is built by Solidworks and is imported into ADAMS. Secondly, the dynamic simulation of the institution under impact load is performed in ADAMS, and the parallelogram rotation angle θ in the parallelogram institution, the spring stiffness coefficient k and the spring installation position in the series spring parallelogram are respectively changed in the simulation. Finally, the simulation results show that the institution has stable gravitational balance characteristics when other initial parameters remain unchanged. This provides data support for the design and manufacture of adaptive training devices for astronauts on the ground.
Current trajectory control of induction motor based on MATLAB
Chenglu Ma
Aiming at the problem of low efficiency of asynchronous traction motor, the maximum torque to current ratio (MTPA) control strategy is applied to control traction inverter, and MTPA control under voltage limit ellipse is analyzed. The simulation results show that MTPA control can run stably in full speed range, improve efficiency of induction motor and increase stability of system.
Multi branches dilated CNN federated learning for transmission line fault diagnosis
Wenhao Sun, Hongbo Ma, Wei Li, et al.
Using convolutional neural network for transmission line fault diagnosis is an accurate and effective method, but it relies on a large amount of data with positive labels and is limited by kernel size that decides the receptive field. However, it is difficult to centralize data in reality, which causes low accuracy of the model. Federated learning has made great progress recently, and it is possible to train a model with high accuracy without centralizing data. In this paper, we propose a transmission line fault diagnosis method based on multi-branch convolutional neural network combined with federated learning. First, we design a novel three branches network with two dilated convolution kernels to increase the receptive field of the kernel. Then we integrate it into the federated learning framework to expand the amount of data used to train the model while preserving data security and privacy. The experimental results show that our method is feasible and can effectively improve the accuracy of the model, and provides a new idea for transmission line fault diagnosis.
Study on force-chain-resistance network structure of pressure control granular material
Yuhao Zhu, Enyuan Dong, Yu Zhu, et al.
Based on the good conductive properties of pressure control granular materials, this paper selects a typical pressure control material titanium diboride (TiB2) as the research object, through the effect of the change of the pressure control resistance value of the particles. Firstly, the force chain structure of particles at different heights was studied by simulation. Then, a method of constructing force-chain-resistance network is proposed, and the rationality of the model is verified by experiments. Finally, the development law of resistance changes with pressure is deeply analyzed, and the structure of force-chain-resistance network effectively combines macroscopic materials and microscopic particles organically, which provides a certain theoretical basis for the resistance response of granular materials with pressure, and provides a reliable basis for its application in the field of electric power.
Research on landslide control technology of transmission line tower foundation
With the rapid construction of UHV transmission lines, the geological disasters along these lines are increasing, which seriously threatens the security and stability of lines and thus imperils the intrinsic safety of power network. At present, there are still insufficient researches on the safety prevention of landslides in the tower foundations of transmission line. On the basis of the existing researches of slope safety protection technology, the early protection technology for tower foundation landslide under different engineering stages (planning and design stage, construction stage, operation and maintenance stage) and different disaster modes (retrogressive type, trailing edge loading type, mixed type) are discussed and analyzed. At the same time, from the three time scales of pre-disaster protection, immediate response and post-disaster management, this paper systematically summarizes engineering protection measures of landslide in tower foundation. Based on the research of this paper, it can provide effective support for the safety protection of landslide in tower foundation.
Design of multi-lane line detection algorithm based on semantic segmentation and clustering
Ruijia Lan, Yaohua Deng
In order to improve the detection accuracy and speed of lane detection, this paper proposes a multi-lane line detection algorithm based on the combination of semantic segmentation and clustering. First, we need to process the dataset, use a new semantic segmentation network to obtain lane instances, then perform binary segmentation on the image and embed a vector attribute to distinguish which lane the pixel belongs to, and then combine the two parts of data. Perform clustering and use polynomial fitting method to get the lane object on the image. After experimental testing, the detection speed of the algorithm reached 72fps, and the accuracy rate reached 96.5%, indicating that the algorithm has a high detection accuracy and speed.
Development of a crystal oscillator taming module based on PID control algorithm
Ming Yan, Shengnan Zhang, Fucheng Yin, et al.
This paper introduces a simple oven controlled crystal oscillator (OCXO) taming module developed by using high precision time measurement technology, Kalman filtering algorithm and PID feedback control principle. This module can discipline OCXO of frequency accuracy 10-7 to 10-10 without using FPGA and complex algorithms, and is suitable for device development and achievement transformation of researchers who are new to the field of time-frequency measurement. Due to its small size, it can also be used in the time calibrator, time synthesizer and other standard instruments that allow the input of external frequency standard, so as to further improve the time frequency parameter of the equipment.
Magnetic anomaly signal detection using adaptive stochastic resonance system
Zhongyan Liu, Yujing Xu, Wang Liu, et al.
The SR (Stochastic Resonance) system possesses the ability to take advantage of the background noise to enhance the weak signal. And it provides a new approach to detect the weak magnetic anomaly signal embedded with complex geomagnetic environment noise. However, the system output is directly influenced by system structural parameters, the inappropriate choice of parameters will lead to a sharp decline in the detection performance of the system. Aiming at this target, we proposed an adaptive stochastic resonance (ASR) system employing the kurtosis index as the criteria to automatically adjust the system structural parameters, which can perform well in the detection of magnetic anomaly signal with background noise. The simulation and experiment are conducted, and the results indicate that it is effective. In details, compared with the traditional SR detector, it has an incremental detection probability of 12% ~20% when the input SNR was between -3dB and -1dB.
Variable inertia virtual synchronous control strategy for cascaded H-bridge grid-connected inverter
Wenmao Wu, Youyuan Ni, Fusheng Wang
A virtual synchronous control strategy based on variable inertia for the cascade H-Bridge grid-connected inverter control system is proposed in this paper, which is involved in the grid frequency regulation. Compared with the constant virtual inertia, the variable inertia can slow down the frequency sag or speed up the frequency recovery process when the frequency of the grid changes, thus increasing the damping of the system. In this paper, the variable inertia mechanism is introduced, and the control strategy of virtual synchronous machine grid-connection based on variable inertia is analyzed in detail. Finally, the MATLAB simulation model of the 3-phase 12-module cascade H-bridge virtual synchronous machine is built to verify the correctness of the proposed control strategy.
Smoke sensor for intelligent power distribution room
Min Zhang, Jian Fang, Yong Wang, et al.
In order to improve the environmental monitoring and safety protection level of the power distribution room, and reduce the fire hazard, a smoke sensor suitable for the power distribution room is designed. The principle, circuit design, software design and functional parameters of the sensor are introduced in detail. The smoke sensor adopts the photoelectric principle with optical labyrinth for smoke concentration detection, and uses GD32E230G8U6 single-chip microcomputer for data processing. Through data transmission and communication based on ZigBee wireless sensing technology with the PC, the fire situation can be determined in time. At the same time, we added a power monitoring module, through which we can monitor the power supply and give early warning of power failure. Thus, it can achieve remote access to the battery voltage and help to change the battery in time, which reflects the flexibility of the smoke sensor. After performance test, the designed smoke sensor can adapt to the temperature range of -25℃~55℃, and can meet the rigorous level 3 standard stipulated by the electrostatic discharge immunity test, and has certain electromagnetic compatibility. In summary, this smoke sensor has the advantages of high performance, good stability, small size, and low power consumption, which meets the intelligent power distribution room application requirements.
Detailed explanation of brushless DC motor control and power MOSFET drive application
Qing Xiang, Feng Li, Paulo Cesar Morais, et al.
Power MOSFETs are widely used in circuit design, such as AC signal amplifiers, DC signal amplifiers, digital signal amplifiers, wireless signal amplifiers, power drive controllers, DC-AC inverters and many other applications, which tends to replace bipolar transistors. In order to fully understand the characteristics and applications of MOSFETs, this paper combines several typical applications in the field of BLDC motor drive to explain in detail the typical circuits and usage characteristics of MOSFETs in power drive. Innovations in this subject can use the present report as a starting point.
Airborne gravimetry and error compensation based on the undulating flight of UAV
Yong Wang, Juliang Cao, Ruihang Yu, et al.
With the rapid development of UAV technology, UAV as a measurement carrier has been widely used. This paper introduces the basic principle of Strapdown airborne gravimetry. The vertical gravity disturbance is compensated by the error parameter estimation method. The experimental results show that UAV has the characteristics of no airport support and short preparation time before measurement. The internal coincidence accuracy is 0.50mGal under the condition of undulating flight, 1.26mGal under the condition of large maneuver, and 0.47mGal and 0.84mGal respectively after compensation. The internal coincidence accuracy shows that the gravity measurement accuracy is high and the instrument stability is good under the condition of undulating flight, which also shows the feasibility of UAV in airborne gravity measurement. The compensation results show that the error parameter estimation method is suitable for UAV airborne gravity measurement in undulating flight conditions.
Design and calibration experiment of six-dimensional force sensor for heavy-duty manipulator
Xiuyu Li, Yanzhao Yin, Quan Sun, et al.
For the application background of multi-dimensional force and moment information collection of heavy-duty robotic arms. Firstly, a six-dimensional force sensor with overload protection function is designed. Secondly, a finite element analysis model of the elastic body of the sensor is established, and the sticking position of the resistance strain gauge is determined. The calibration device is used to calibrate the force and torque of the six-dimensional force sensor. Finally, the linear mean calibration algorithm is used to realize the decoupling of the calibration experimental data.
An improved detection method of metal product surface damage based on super-resolution reconstruction
In order to solve the problem of slow detection efficiency and low accuracy in continuous detection of metal prints. A detection method for printing defects and surface damage of metal prints based on super-resolution reconstruction is proposed. The core content of this method is the use of image quadratic linear interpolation. First, according to the spectral reflectance characteristics of different surfaces of metal prints, a method of imaging features that can clearly reflect the image is proposed. In this paper, an image super-resolution registration method based on quadratic linear interpolation is proposed, and finally a method based on image threshold segmentation to reduce noise interference is proposed, which effectively improves the detection accuracy. Experiments show that the error of the detection method for printing defects and surface damage of metal prints based on super-resolution reconstruction is less than 0.03mm. Field experiment results show that this method is an effective non-destructive testing method for metal printing.
Channel transmission fault detection method for smart grid based on multivariate data analysis
Weifeng Luo Sr.
Based on the analysis of the channel characteristics of transmission lines in distribution network, the channel characteristics of different types of transmission lines are analyzed and compared, and the channel attenuation model of transmission lines is established. Aiming at the multi-path fault of smart grid transmission channel, a multi-path fault detection method is proposed. Through the establishment of multi-channel model, the transmission characteristics of power line are studied and analyzed by using nonlinear least square method and multi-channel parameter estimation method. The power line fault location under high resistance condition is analyzed, and the relationship between the parameters and the power line fault is obtained. On this basis, the topology of power equipment network structure is identified, and the subspace method is compared with the matrix beam method. Based on the root adjacency relationship, the network topology is reconstructed by dynamic tree reconstruction. In the process of smart grid channel transmission, multivariate data analysis method is used for fault detection, and it is verified by experiments. The results show that the channel transmission fault detection method of smart grid based on multivariate data analysis has high calculation accuracy and can meet the research requirements.
Design of integrated fire protection system for building electrical fire based on multi-sensor data fusion
Youhua Li
Aiming at the problems of untimely fire warning and unreliable warning information in traditional systems, this paper designs a building electrical fire integrated fire protection system based on multi-sensor data fusion. This paper designs a multi-sensor data fusion fire-fighting system hardware module, and realizes data processing through environmental brightness sensor, smoke sensor, temperature sensor, and infrared flame sensor. At the same time, a data fusion algorithm is designed, and the number of nodes in the input layer is set to 4.At the same time, in order to reduce the data fusion error, the average value of the white noise variance is solved, so as to realize the integrated fire protection system of building electrical fire. Experimental results show that the fastest warning time of the designed system is 0.22s, and the predicted fire probability is more similar to the actual fire probability, indicating that the system has higher practicability.
Calculation of distribution elliptical of the longitudinal torch community point for a certain type special incendiary bomb
Xiu-Yuan Tang, Xin-Yue Li, Zhi-Hua Dong
According to the external trajectory characteristics of incendiary bombs, the method for establishing the elliptical dispersion model for the longitudinal torch of a certain type special incendiary bomb was proposed. Then the theoretical calculation methods for the distribution elliptical of the longitudinal torch community point and the distribution area of the impact point were established. These methods could decrease the test cost and ensure the calculation accuracy, which has high application value.
Application of ground penetrating radar to fault analysis in construction of grounding device
Wentao Chen, Tianbo Wu, Dilyar Dolkun
Substation grounding device is a hidden project, there is no effective detection means for fault analysis. In this paper, the detection technology of ground penetrating radar is applied to the analysis of abnormal current when the grounding device of EHV substation is connected. Through the positioning analysis of ground penetrating radar, it is determined that the abnormal current is caused by the closed loop formed by the grounding device after being connected and the loop current formed under the action of surrounding electromagnetic environment. Through the detection of ground penetrating radar technology, the problems of abnormal current and spark discharge in the laying and connecting process of dry-type reactor grounding device were successfully solved to ensure the smooth implementation of infrastructure projects.
Design of a fast on-line measurement device for deflection of assembly car body based on wireless laser sensing
Baitian Ouyang, Fushen Cai, Jiafu Cai, et al.
Traditional assembly car body deflection measurement methods have the disadvantages of complicated device layout, cumbersome testing process and high requirements for technicians. A fast online measurement device for assembly car body deflection was proposed. Non-contacted measurement on assembly car body was realized by using laser displacement sensors. The communication mechanism of ADS1115 analog-to-digital converter (ADC) module and ZigBee module was researched on in order to realize wireless transmission of deflection measurement data. Fast online measurement software for assembly car body deflection was developed by LabVIEW, displaying assembly car body deflection measurement data, printing and reporting the assembly car body deflection measurement results. The results had shown that using the device to measure car body deflection can realize rapid deflection measurement, improving the automation and intelligence of the assembly car body deflection measurement.
Method of rebar detection in cement pole based on BP neural network
Zongyi Luo, Xiang Bao, Jianjie He, et al.
Power cement poles made of reinforced concrete are widely used in low-voltage transmission lines as pillars and overhead wires. However, when the manufacturer uses stretched and polished waste rebar whose diameter is smaller than the designed size and the quality is unqualified, it will greatly increase the potential safety hazards of the transmission line. Therefore, the accurate detection of the parameters of the rebar in the cement pole can effectively maintain its safe operation. There are many concrete rebar detection methods, but most of them cannot simultaneously measure the diameter and buried depth of the rebar. Therefore, the article proposes a rebar magnetic measurement method based on BP (Back Propagation) neural network algorithm. First, the article theoretically analysis the influence of the magnetization effect of rebar on the space magnetic field and the principle of magnetic measurement, and then builds an experimental platform to verify the feasibility of the detection method, and further combines the BP neural network algorithm model to train and verify the detection data, finally obtain accurate rebar diameter and buried depth parameters.
Research on fuzzy logic control allocation of missile compound control system
Jie Chen, Hongchao Zhao
A fuzzy logic control allocation algorithm is proposed to deal with the control allocation problem in the compound control system of air-to-air missile. The control law of compound control variable is designed by dynamic surface control method. In the design process the extended state observer is used to estimate the lumped uncertainties, and the smooth second-order sliding mode control algorithm is adopted to design the control law. They achieve the goals of improving robustness and weakening chattering phenomenon. The fuzzy logic control allocation algorithm is used to break the compound control variable into direct thrust control command and fin deflection control command. In order to test the control effect of the designed compound control system, the comparison simulation experiments are performed for both the compound control system based on fuzzy logic control allocation algorithm and the traditional aerodynamic force control system. Simulation result comparison shows that the designed compound control system has better control effect.
Research on GIS partial discharge location and monitoring system based on loop signal circle
Ruiqiang Zhang, Yanjun Zhang, Su Xu, et al.
Partial discharge(PD) detection is an important means to monitor and diagnose the insulation condition of electrical equipment. Detecting the partial discharge condition of the equipment and finding and dealing with the insulation defects in time can effectively avoid the occurrence of insulation faults[1]. In this paper, a GIS partial discharge location and monitoring system based on loop signal loop is designed. By studying the principle of loop time difference location and signal processing algorithm of UHF signal, a GIS Partial Discharge Monitoring System Based on UHF method is developed to realize on-line monitoring and location of partial discharge[2]. The later test shows that the monitoring system has strong stability, high sensitivity and accurate positioning, which can meet the requirements of on-line monitoring and positioning of partial discharge in GIS.
A kind of small omnidirectional antenna for EMC measurement
Nan Wang, Chang Zhou, Jing Xia, et al.
In this paper, a small omni-directional EMI test antenna with special design is introduced. By selecting the electrical performance parameters of the antenna magnetic substrate, the antenna could be effectively miniaturized. At the same time, based on the antenna optimization design technology, the radiation characteristics of the antenna within the working frequency band could also be ensured. Finally, through the optimization of various parameters, the antenna size is no more than 50mm*45mm*45mm, gain is no less than -5dbi and the radiation in Y-Z plane is omnidirectional. The research and development of the antenna has certain significance for the EMC test in RF band.
Design of power quality abnormal data identification and verification system
Sixu Huang, Guo Zhao, Jiang Guo, et al.
Aiming at the problem that abnormal data in the data set greatly reduces the quality of data, this paper studies several existing mainstream methods of abnormal data identification and verification, and selects three kinds of abnormal data detection methods according to the characteristics of power quality basic data, including setting threshold discrimination method, data horizontal comparison method and improved K-MEANS algorithm. This paper also designs the power quality abnormal data identification and verification system, using the above three methods to identify and verify the power quality abnormal data.
Development and experimental verification of physical platform for single station flexible DC converter valve
Longhao Liu, Rongrong Zhan, Long Jin, et al.
In order to test and verify the power control characteristics and fault characteristics of flexible DC grid based on MMC, a physical platform of single ended flexible converter valve is developed. The platform adopts the pseudo bipolar connection form to form a two terminal transmission structure with the DC power supply. The sub module adopts half bridge MMC, and multiple fault points are configured on the AC and DC sides, which can create different types of faults. Based on the physical platform of single station flexible DC converter valve, the normal operation, power step and simulated fault tests are carried out. The test results show that the platform meets the test requirements of power control characteristics and fault characteristics of flexible DC grid.
Influence analysis of pipe parameters of double elbow of fish suction device on pipe flow field based on liquid-solid coupling
Song Yin, Pengyue Sun, Shujiang Wu, et al.
In order to study the influence factors of suction fish pipe erosion phenomenon, based on turbulence theory and Finnie, DNV, E/ CRC erosion models, the COMSOL finite element model was established to calculate and analyze the erosion law of suction fish pipe under the conditions of bend angle, input pipe length and intermediate pipe length. The results show that when the bending angle increases gradually, the maximum erosion velocity increases firstly and then decreases. When the bending angle is 60°, the maximum erosion rate is reached. With the increase of elbow angle, the maximum erosion position of the pipe gradually shifts from the outer area of the inner wall at the junction of the pipe segment and the elbow to the outer part of the inner wall of the elbow. With the increase of the length of the input pipe, the maximum erosion rate decreases gradually, and the decreasing rate of erosion rate tends to be gentle. When the length of intermediate pipeline is small, the effect of the offset erosion rate is small, and the maximum erosion rate decreases with the increase of the length of intermediate pipeline.
Research on the model predictive control strategy of VSC rectifier station connected to wind farm
Ye Tian, Yu Yu, Shuang Lv, et al.
The PI double closed-loop control is often used in a VSC rectifier station connected to a wind farm, which has a complex structure and needs to set PI parameters. It is easy to interact with the PI controller of a doubly-fed induction generator and has a slow response speed. In this paper,the model predictive control strategy of a VSC rectifier station connected to a wind farm is proposed. By deriving the discrete mathematical model of WF-VSC, the electrical value in a control cycle is predicted, and a reasonable cost function is constructed to obtain the optimal switching state at the next moment, to realize the constant AC voltage control of WF-VSC. Finally, the constant wind speed and fluctuating wind speed conditions are simulated in MATLAB. The simulation results show that the designed model predictive control system has faster dynamic response speed and higher control precision than PI control.
Comprehensive application of leakage detection technology in subway deep foundation pit
Weisheng Rao, Jiacheng Li, Longjian Feng
In the engineering of deep foundation pit, in order to ensure the safe excavation of foundation pit, the leakage detection of foundation pit retaining structure can be carried out before excavation, with the purpose of proving the water resistance of retaining structure and treating the possible leakage points in advance. During the excavation of the middle air shaft of a city subway, water gushing accident occurred. After the foundation pit was partially back-filled, a series of reinforcement measures were taken to meet the secondary excavation conditions. In order to confirm the reinforcement effect before excavation, the leakage of the middle air shaft reinforcement was comprehensively detected. The results of the secondary excavation of the middle air shaft show that the water resistance of the foundation pit enclosure system revealed by the leakage detection technology is completely consistent with the actual situation, which proves that the technology has a broad application prospect in the field of deep foundation pit leakage detection, and can be popularized in engineering.
Research on soft sensing method of pumping unit system efficiency based on KPCA and SVR
Kun Ma
The system efficiency is an important technical parameter to measure energy consumption of pumping units. It is of great significance to study the simplified calculation method of the system efficiency for saving test cost and objectively evaluating the implementation effect of energy saving and consumption reduction technology of pumping units. In order to solve the problem that the existing calculation methods of pumping unit system efficiency depend on many parameters, and some parameters are complex or difficult to obtain, a soft sensor model building method of system efficiency based on the combination of KPCA and SVR is proposed, Kernel principal component analysis introduces kernel mapping method into principal component analysis, which can effectively deal with nonlinear data. Through nonlinear function transformation, the data is projected into high-dimensional feature space, and the nonlinear distribution characteristics of data are obtained. Then, SVR algorithm is used to establish a soft sensor model which can accurately predict the efficiency of pumping unit system. The test results show that compared with the traditional model building method, the soft sensing model based on KPCA and SVR has higher measurement accuracy and generalization ability, which can effectively reduce the monthly testing workload of pumping units and reduce the production and operation costs of the oilfield.
Ultrasonic inspection of S line of 7050 aluminum alloy friction stir welding
Hexiao ., Ning Ning
By analyzing the formation mechanism of S-line in Friction Stir Welding (FSW), simulating the test pieces of Friction Stir Welding (FSW) of aluminum alloy with S-line defects, and using high frequency ultrasound to detect S-line defects, this method can be used as an effective method to detect S-line defects in Friction Stir Welding (FSW) of aluminum alloy.
Design of wavelength-locking module for VCSEL
Jing Lin, Pengling Dong, Shijia Wang, et al.
Aiming at the wavelength locking of vertical cavity surface emitting lasers (VCSEL), the principle of atomic transition spectrum locking based on low frequency modulation and demodulation was analyzed, and the laser wavelength locking circuits were designed and realized by using digital phase detection algorithm. VCSEL wavelength locking circuits were mainly composed of temperature control circuit, laser driven current source and digital phase detector, and the principle design of each circuit was given respectively. The designed VCSEL wavelength locking circuits have been tested and successfully applied to coherent population trapping (CPT) atomic clock, locked the multi-spectrum of 133Cs and realized the observation of CPT signal.
Multi-modal sensing positioning technology for intelligent verification of stacked kilogram weights
Di Zhao, Jian Ma, Wen-bin Yu, et al.
Unmanned verification of weights requires machines to grab and carry weights on behalf of people. High-precision spatial coordinates of weights are the key parameters for unmanned verification of weights. This article starts with multimodal sensing positioning technology, and proposes a spatial positioning technology solution based on multi-modal sensing stacking kilogram weights. Through technical solutions such as deep learning, LM optimization, and least squares fitting, the stacking of kilograms under fluorescent lighting is realized. The spatial positioning of the weight handle forms a versatile method for positioning the handles of stacked kilogram weights. Experiments were carried out by simulating the construction of 3×3×2 stacked kilogram weights in different states. The results showed that spatial positioning accuracy of the stacked weights instance is millimeter-level, and the calculation time of the overall algorithm is less than 6s, which can realize the spatial positioning of stacking kilogram weights in complex environments.
Integrated robotic measurement and machining technology for large castings
Zhaoyang Liao, Zhihao Xu, Qinghui Wang, et al.
In the past, for large castings, manual or large special equipment are need to complete the measurement and machining. With the advantages of high flexibility and large workspace, industrial robots provide a promising alternative. In this work, the rear axle housing machining is taken as an example. Firstly, the blank model is obtained by multi-angle point cloud scanning and fusion based on FPFH method. Then, after aligning the coordinate system, the height of the residual material is calculated. To ensure that the robot can process a complete workpiece with high stiffness, machining region division is carried out, and the robot posture and workpiece’s orientation are optimized. Finally, the process of integrated robotic measurement and machining is verified by simulation and experiment, and the machining results are analyzed.
Study on wave propagation of dynamic compaction for ground improvement by considering nearby oil pipeline
Bo Li, Dong-sheng Xu, Fu-guang Zhu, et al.
The dynamic compaction method is widely used in construction engineering because of its simple construction method, good economy, and obvious reinforcement effect. In this study, the vibration propagation behavior and isolation mechanism for dynamic compaction are examined based on a field test to investigate the impact on the oil pipelines. A power function was proposed to describe the attenuation of normalized velocity for the ground vibration. The attenuated curve was varied with the number of drops during dynamic compactions. With an isolation ditch, a sudden drop of velocity for ground vibration can be observed during field tests. It means that the vibration wave of the soil behind the vibration isolation trench can be reduced to achieve the effect of vibration isolation.
Research and design of the information collection system of human life characteristics
WuJie Zhang, Ming Wei Sr., JunJie Wan, et al.
The whole system is divided into data acquisition subsystem and control terminal subsystem. Data acquisition: consists of power supply circuit, isolation circuit, ADS1292 heart rate sampling circuit, ADS112C04 temperature acquisition circuit, IMU901 ten-axis accelerometer module and other circuits; the control terminal uses STM32 Series of microcontrollers, the communication module uses ATK-BLE wireless blue-tooth and WIFI module. The paper has completed the analysis and processing of heart rate data, temperature measurement, acceleration, attitude and air pressure measurement. Overall the design task was completed. The device has broad application prospects in family personal monitoring and medical care.
An improved distortion feature information restoration method
Accurate acquisition of image features is particularly important for environmental perception of robots. It is difficult to obtain the image features accurately and effectively because of the interference of high-light reflection of the parts’ surface. To solve this problem an improved distortion feature information restoration method is proposed in this paper. First, an image acquisition method is proposed, which can successfully reduce the effect of high-light reflection. Then, an image quality evaluation method based on cosine similarity is proposed to realize the accurate evaluation image quality of highlight reflection image. Finally, an image quality compensation method is proposed to effectively reduce the effect of high light distortion on feature extraction. Contrastive experiments fully prove that the method proposed in this paper can effectively improve the problem of feature recognition caused by local strong light interference, and the accuracy of image surface feature extraction after compensation is significantly improved.
Small crack detection method for cylinder block based on improved SSD model research
Lingju Kong, Cheng Sun, Weijie Li, et al.
In order to detect small cracks on the surface of casting workpieces in real time, this paper proposes a feature fusion target detection algorithm based on SSD network. First, the image is reshaped and fed into the network to generate multiple feature maps of different scales. First, the image is resized and fed into the network to generate multiple feature maps of different scales. Feature fusion is performed between feature maps to generate new feature maps. Finally, multiple new feature maps are used to predict crack coordinates and probability. After experimental testing, the detection speed of the algorithm in this paper reaches 87fps, while the accuracy rate reaches 92.3%, indicating that the algorithm has high detection accuracy and speed.
Research on fault monitoring technology of station-use low-voltage AC distribution system
Chao Xu, Jiangxiong Wu, Bin Chen, et al.
As the main power supply system of the power supply network, low-voltage AC power distribution system has wide power grid coverage. Considering the safety of electrical equipment and personnel, the AC power system of the power grid is designed as a grounding system. At the same time, the power distribution line is designed with many fault detection and protection measures. The station-use AC system is an indispensable link to ensure the safe and reliable transmission of electric energy in the substation. The station-use electricity is mainly used to provide power for the primary and secondary equipment in the substation. Due to the several important devices in the substation, the power cannot be cut off at will. To ensure continuous power supply, protection measures of distribution lines are slightly weakened to enable continuous power supply. However, although power production improves the power supply quality, power production accidents caused by station-use AC system failures have attracted the attention of power production companies. In this context, this paper analyzes the insulation fault characteristics of station-use AC low-voltage power distribution system, summarizes the fault hazards, studies the methods for insulation fault detection, and proposes the idea of constructing an insulation fault monitoring system for the station-use AC power distribution system.
The accurate recognition system of citrus flowers using YOLOv4-Tiny lightweight neural network and FPGA embedded platform
Shilei Lyu, Yawen Zhao, Ruiyao Li, et al.
Citrus flower recognition is the key technology of flower thinning, pollination and yield prediction in citrus orchard production and management. Current object detection algorithms are mostly limited into server computing environment, which is difficult to meet the application requirements of accurate recognition of citrus flowers in a natural environment. A citrus flower recognition model based on YOLOv4-Tiny lightweight neural network was proposed by using software and hardware co-design pattern in this paper. Through the frame transformation quantification and compilation of the recognition model, the dynamic link library was generated and transplanted to FPGA embedded platform. So, the citrus flower accurate recognition system was designed and implemented. The comprehensive recognition accuracy of citrus flower recognition model deployed on embedded platform for flowers and buds was not less than 89.30%; The size of the quantization recognition model was 5.64 MB; The accuracy loss of the model was 1.77%; The frame rate was not lower than 16 FPS. It can meet the requirements of real-time accurate identification of citrus flowers.
Analysis of abnormal running behavior of mechanical operators based on sensor detection
Hongqi Luo, Xia Liu, Yongbao Wei
The dangerous and harmful factors of machinery manufacturing mainly include human unsafe behavior and consciousness factors, unsafe state factors of equipment and adverse environmental factors. The characteristics and classification of abnormal behavior are analyzed, the detection methods of operators' abnormal running behavior are compared, and the discrimination basis of operators' abnormal running behavior is analyzed. The wearable inertial sensor is studied. The acceleration sensor is used to measure the acceleration of the measured object, and the gyroscope sensor can measure the angle of the human body relative to the ground. MPU9250 is selected as the measurement tool of acceleration and angle to identify the abnormal behavior of the human body, and cooperate with the single chip microcomputer, It is conducive to the detection and early warning of abnormal behavior of mechanical operators.
Effect of inlet temperature on CO2 heat transfer at supercritical pressure in vertical upward flow
Bin Peng, Kaigang Gong, Bingguo Zhu, et al.
In this paper, the heat transfer characteristics of CO2 at supercritical pressure in a vertical tube with an inner diameter of d=10 mm are investigated numerically under uniform heating condition. The SST κ-ω turbulence model are used. Firstly, the reliability and accuracy of the numerical model are verified, and the numerical results can capture the wall temperature curve well. Secondly, thermophysical properties of CO2 under different pressures are analyzed. Finally, the influence of inlet temperature on CO2 heat transfer at supercritical are studied. The results indicated that when the inlet temperature is less than the pseudo-critical temperature, a temperature overshoot appears, belonging to heat transfer deterioration. As the inlet temperature decreases, the peak point of wall temperature moves towards the low enthalpy region. When the inlet temperature is greater than the pseudo-critical temperature, with increase of bulk fluid enthalpies, wall temperatures are either gently increased, belonging to normal heat transfer. Our results showed that the inlet temperature has a great influence on the CO2 heat transfer at supercritical pressure. The pseudo-boiling heat transfer mechanism perfectly explains the above phenomena.
Research on the critical impact velocity of droplets impacting metal grid and breaking into sub-droplets
Zhenyu Yang, Zhen Li, Xin Ai, et al.
Pesticide drift occurs in the process of pesticide spraying by UAV (Unmanned Aerial Vehicle) and other plant protection machinery. This study proposed a grid atomization method to deal with pesticide drift. First, large droplets that are not easy to drift are sprayed by spray machinery, and then large droplets impact on a metal grid placed above target and break into small droplets suitable for attachment to target, thereby achieving the purpose of reducing pesticide drift and increasing pesticide deposition rate. In order to better realize the breaking of large droplets into small droplets in agriculture, this study researched the influence of different grid materials and grid specifications on critical impacting velocity of large droplets breaking into smaller droplets after impacting it on grid. This study used a high-speed camera to photograph the process of droplets being fragmented into smaller droplets. The size of droplet and impact speed are obtained by image analysis. The experiment results show that there is no obvious difference between the effect of the three materials of stainless steel, nickel and copper on critical impacting velocity under the same grid specifications; Under the experiment conditions, critical impact velocity increases with the increase of mesh number.
Capacity and energy test analysis of lithium-ion traction battery pack for high energy applications
Jinghong Jiang, Zhimao Ming, Guixiong Liu, et al.
In view of the complicated testing process of high energy applications of lithium-ion traction battery packs for electric vehicles, based on current standards, the capacity and energy test programs under working conditions of 25℃, 45℃, and -20℃ were designed respectively, and tests were carried out according to the formulated programs. The test results show that under high temperature conditions, the discharge capacity and discharge energy of the battery pack are significantly reduced, and the loading of the thermal management system has a greater impact on the discharge capacity and discharge energy of the battery pack. The temperature rise during the discharge is related to the temperature of the working condition. The higher the temperature of the working condition, the lower the temperature rise during the discharge. The formulated high energy application lithium-ion traction battery pack capacity and energy test program can effectively complete the corresponding application test analysis, the program is simple to operate, and the results are accurate and effective.
One hypersonic unmanned aerial vehicle sensor failure controller design
Jie Chen
Hypersonic unmanned aerial vehicle control system has very time-varying dynamics, strongly nonlinear, prominent strong coupling characteristics comparing with traditional aircraft. A variety of temperature sensor failure and other causes of fever and some actuator failures and other issues, the nonlinear observer and controller are designed respectively to solve the sensor failure problems encountered for hypersonic unmanned aerial vehicle. The dissertation designs a new standard expanding Luenberger observer to estimate convergence state vector, and brings forward dynamic surface adaptive backstepping control law to guarantee the system bounded. The dissertation the dynamic surface control strategy is adopted to eliminate the traditional inversion of the dimesion explosion by using a series of first order filters. Simulations of hypersonic unmanned aerial vehicle are used to verify the above theories.
Intelligent Instrumentation and Automation Equipment
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Design of sunflower double row planting film mulching machine
Mingming Liu, Guodong Wu, Kai Xia, et al.
In order to improve the efficiency of sunflower planting and solve the problem of high labor intensity of artificial planting, this paper designs a kind of planting film mulching integrated machine for sunflower planting. Firstly, the overall scheme design of the planting film mulching integrated machine is carried out, and then the compression device, ditching device, metering device and soil covering device are designed and calculated. The experimental results show that the designed planting film mulching integrated machine can effectively improve the sowing efficiency of sunflower, and the working efficiency is 0.2 hectares/h. It can effectively improve the working efficiency of farmers, save working time and reduce labor force, and provide certain application reference for solving sunflower planting.
A new design of sound-absorbing structure for prefabricated substation
Jingbo Liu, Qiong Yang, Tian Tian, et al.
As the prefabricated substation adopts the enclosure partition wall structure with light steel double-layer thin plate, the impact of its low-frequency noise on the environment is bound to be more prominent. This paper analyses the main causes and characteristics of noise in fabricated substations. The main source of noise in fabricated substations is transformers. The low-frequency components of the noise generated by them account for a relatively large proportion. The sound pressure level of noise is the highest at 200Hz and 315Hz. In order to reduce the impact of noise on the environment, this article introduces several low-frequency sound absorption and sound insulation structures used, analyses their principles, and proposes a sound absorption and sound insulation enclosure structure suitable for prefabricated power stations to improve its low-frequency sound absorption performance. By arranging diaphragm ribs, the structure moves the resonant frequency band to high frequency, which improves the sound insulation of low frequency. Owing to the adoption of more ribs and stiffening plates, the number of resonance peaks in the low frequency band is reduced, which is beneficial to the sound insulation performance of the double-layer structure. A fireproof board is added between the inner and outer partitions to reduce the influence of the gap on the sound insulation and improve the fireproof performance of the structure. The final sound insulation at low frequencies is higher than 40dB, which will greatly improve the noise pollution to the environment.
Vibration simulation and test of shunt reactor under DC bias
Yuan Zhou, Tian Tian, Xiongfei Yu, et al.
Shunt reactor plays an important role in transmission system, which can provide reactive power compensation for transmission line and improve the quality of transmission line. But in the field operation, the shunt reactor will produce a large degree of vibration and noise, and even endanger the safety of indoor substation floor. Therefore, based on the vibration effect of shunt reactor, this paper puts forward the vibration variation law of shunt reactor under different DC bias. In this paper, the finite element model of reactor is built by COMSOL finite element simulation software to analyze the flux density distribution of reactor core under different direct flow injection, and then analyze the change trend of stress and strain. Then the reactor vibration test system is built on site, and the vibration acceleration curve of the reactor is collected and analyzed. The correctness of the reactor model is verified from the side. This study can provide a strong reference for the reactor vibration and noise reduction.
Study of application of composite sampling and improved LightGBM algorithm to the diagnosis of unbalanced transformer fault samples
Shanshan Liao, Dongsheng He, Yangyang Xie, et al.
A new diagnosis method for unbalanced transformer fault samples was proposed in this study to solve the problems of low accuracy and long training time existing in the traditional transformer state evaluation and diagnosis algorithms under un-balanced sample distribution. First, the improved SMOTE alg-orithm was used to collect the minority among the unbalanced transformer fault samples, which were then normalized. Next, the ENN algorithm was adopted to solve the data noise problem generated after sampling, followed by the under-sampling pro-cessing, and the samples of different fault types were made to reach the balanced state through the composite sampling. In the end, the overfitting problem was solved through the improved LightGBM algorithm, and the balanced transformer fault sam-ples were diagnosed. The experimental results showed that under unbalanced samples, the diagnostic accuracy rate of the proposed method reached 95.1%, which was 24.7% higher than that reached by other traditional fault diagnosis methods. Moreover, the proposed method improved the indexes like recall rate, F1-score value and precision ratio by 20%, thus solving the low fault diagnosis accuracy and long training time of traditional artificial intelligence (AI) algorithms under unbalanced data distribution of transformer fault samples.
A kind of intelligent tunable EMI filter
Chang Zhou, Jing Xia, Nan Wang, et al.
A kind of intelligent tunable EMI filter has been designed and optimized in this paper. the miniaturization of the filter could been obtained through the reasonable selection of active devices and the design of intelligent control circuit structure. On the other hand, excellent electrical performance of the intelligent tunable EMI filter within the target frequency band could be achieved by choosing reasonable filter structure and using filter design theory. Through HFSS modeling and simulation calculation, the optimal parameters of the filter can be obtained quickly. The results show that the volume and electrical performance of the EMI filter can meet the design requirements.
Design of DC filter for 24-pulse high power rectifier
Zhuo Ling
Conventional high power rectifier with 24 pulse output usually uses flat wave reactor in the DC side to suppress the ripple contained in the output waveform, so that the output DC is close to the ideal DC. Although this method has good economic benefit, the filtering effect is not good. Firstly, the necessity of installing DC filter is analyzed from the harmonic component. Secondly, according to the impedance-frequency characteristic equation, the parameter calculation formula of the double-tuned filter is deduced. Finally, the ideal output waveform of the main circuit is obtained through Matlab/Simulink simulation, and the feasibility of filtering specific sub-harmonics by the double-tuned filter is preliminarily verified by FFT analysis, and the ideal filtering effect is obtained.
Electromagnetic coupling prediction for the low voltage wire harness of electric vehicle
Guiying Ren, Mingli Zhao, Zilong Wang, et al.
Multi-port network theory can simplify complex systems by the equivalence of ports. Therefore, the wiring harness model is equivalent to the port network in the electromagnetic coupling prediction for the low-voltage wiring harnesses of electric vehicle. The scattering parameters between the ports of the wire harness are obtained by simulation in Feko, then the characteristics of the wire harness coupling network can be established. According to the relationship between the voltage and current of ports, the voltage and current prediction formula of the interfered harness port is derived. Comparing the port current of the interfered harness collected from the vehicle with the current obtained from the simulation, and qualitatively analyzing whether there is a risk of electromagnetic interference, it verified the effectiveness of the multiport network method to predict the electromagnetic coupling between the wiring harnesses. To a certain extent, the EMC performance of the vehicle can be guaranteed if the method is applied to the vehicle development stage.
A novel AEDL network and its application in performance degradation assessment of rolling bearings
Zhigang Liu, Long Zhang, Chengyang Song
Bearing is the most critical component in mechanical equipment, the performance degradation assessment (PDA) of bearing can improve the reliability of equipment. Research on the application of reconstruction-based neural network in PDA, this paper proposes AEDL neural network to assess bearing degradation. First, the time domain and frequency domain are used to extract the signals features. In AEDL neural network, auto-encoder and dictionary learning reconstruct the features. Finally, the reconstruction error is used as the degradation index to assessment bearing degradation. Particle Swarm Optimization (PSO) is to obtain the hyper-parameters of the model, and this paper proposes a new metric Mean- Square-Error-Ratio (MSER) to evaluate the effect of reconstruction. The bearing experimental results indicate the proposed method can track performance degradation effectively and detect incipient damage in time. This paper provides a potential tool for reconstruction-based PDA model research.
Remote interaction system of substation based on mobile terminal
Yongxin Chen, Hong Zhang, Jinkui Huang, et al.
In order to improve the speed and ability of data analysis of substation equipment, a remote interaction system of substation based on mobile terminal is proposed. It is convenient to detect the operation of substation equipment in time and handle the problem. The remote interaction system of substation based on mobile terminal has been verified by experiments, and its performance is better than traditional system.
Parameter optimization design of electric vehicle wireless charging system based on rectifier bridge input impedance analysis
Longfeng Ye, Fusheng Wang, Zheng Fan, et al.
For an electric vehicle (EV) wireless charging system, the stable output and efficient operation of the system are essential. This article first analyzes the characteristics of the wireless charging system based on the dual-LCC compensation topology network, and initially designs the parameters based on the efficiency model. Then the input impedance model of the rectifier bridge is established, which contains two parts: resistance and inductance. On this basis, a compensation network parameter optimization method based on rectifier input impedance analysis is proposed. Finally, a MATLAB simulation model is built, and the effectiveness and feasibility of the proposed optimization method are verified through the simulation results. With the parameter optimization method proposed in this paper, the system can achieve good constant output performance and high efficiency.
Transient analysis of dual active bridges under short circuit at load side
Yirong Su, Fuhu Lv, Huamin Liang, et al.
In this paper, the transient process of double active bridge DC converter under output short circuit fault is analyzed. The internal and external circuits are decoupled by time-domain analysis method, the current and voltage transient quantities of DAB after short-circuit fault are derived in different modes, the overcurrent phenomenon in the transient process is demonstrated, and the most serious overcurrent risk is pointed out. By analyzing the transient process, this paper proposes a method to realize DAB short-circuit fault crossing by series inductance at the output end, and deduces the range of series inductance value, so as to identify short-circuit fault characteristics on the premise of no overcurrent in the circuit. In this paper, a 50kW DAB simulation model is built and verified through MATLAB/Simulink. The simulation and experimental results verify the correctness of the analysis results and the proposed method.
Comparative analysis of resistance models for slurries pipeline transportation
Bojiao Yan, Wenluo Chen, Jing Wang, et al.
The pipeline transportation of slurries has the advantages of high transportation efficiency, clean sanitation and high degree of automation control. In the design of slurries pipeline, the calculation of flow resistance plays an important role in the selection of transportation equipment and transportation cost. This paper summarizes four kinds of calculation models of flow resistance of slurries pipeline transportation, and puts forward the comparison method of models, which has certain practical significance for the selection of calculation models of slurries pipeline transportation.
Discharge fault diagnosis model for transformers based on free characteristic gas
Zhengqi Li, Weigen Chen, Tianyan Jiang, et al.
Transformers are the critical equipment in power systems. During the operation of transformers, there is a risk of discharging faults such as arc discharge. High-energy discharge fault occurs with a large amount of free gas, which causes transformer fire, explosion, and other accidents. Based on this, this paper designs a discharge fault simulation device in transformer oil. It conducts breakdown discharge, spark discharge, and arc discharge tests to collect free gas generated when a discharge fault occurs. This paper selects four typical characteristic gases to form characteristic gas histograms. It uses a support vector machine (SVM) and ant colony optimization support vector machine (ASVM) to establish a fault recognition model to compare and diagnose the characteristic parameters of the map. The results show that the ant colony optimization support vector function can effectively identify the free distinct gas map of the transformer. This model is suitable for diagnosing and analyzing discharging faults of transformers based on free characteristic gases.
Research on equipment identification technology of power monitoring system
Hongjie Zhang, Qi Wang, Tiejun Zheng, et al.
With the rapid development of network technology, a large number of diversified network equipment are applied to the power monitoring system, which not only greatly improves the production efficiency of the power system, but also challenges its own security management. Accurate and comprehensive identification of network equipment is the premise of effective management of network equipment, and also the basis of security threat analysis. In this paper, an equipment identification method based on traffic analysis is proposed. By passively monitoring the traffic in the network, the representative features of the data flow are extracted from multiple dimensions and analyzed. The C4.5 decision tree algorithm is used to generate the identification model, and the equipment in the network is identified by this model, The accuracy rate of equipment identification can reach 94%.
Minimization of entropy generation rate in reverse water gas shift reactor with linear phenomenological heat transfer law
Ming Zhao, Shaojun Xia, Yajie Yu
The reverse water gas shift (RWGS) reaction can convert CO2 into useful industrial raw materials, which meets the requirement and trend of carbon-neutral energy development. For the one-dimensional tubular plug flow RWGS reactor, the heat transfer process was assumed to obey the linear phenomenological heat transfer law ⟨q∝Δ(Τ-1)⟩. Under the conditions that all of the CO yield, inlet temperature, inlet pressure and inlet compositions were given and the temperature of the heat source outside the tube was fully controllable, the minimum total entropy generation rate (EGR) of the RWGS reactor and the corresponding optimal temperature distribution of the heat source outside the tube were solved by applying finite time thermodynamics and optimal control theory. The optimization results were further compared to the performances of two reference reactors with the constant and the linear heat source temperatures and those for the case with Newtonian heat transfer law ⟨q∝Δ(Τ)⟩. The results show that optimizing the heat-source temperature distribution could reduce the total EGR of the RWGS reactor by more than 48% compared to those of the two reference reactors, and the main reduction is the EGR in heat transfer and chemical reaction processes; heat transfer laws have significant effects on the minimum total EGR of the RWGS reactor and the corresponding optimal temperature distribution of the heat source outside the tube. The obtained results in this paper have certain guiding significance for the design of RWGS reactors in actual engineering.
A class of deployable polyhedral mechanisms based on the loop-closed mechanism
Xuemin Sun, Zhiguo Yu, Hongfu Zhao
A method of constructing deployable polyhedral mechanisms based on loop-closed mechanism is proposed, in which the loop-closed mechanism is a loop with anti-parallelogram units connected end to end. First, according to the construction methods of the 6R mechanism and the 8R mechanism and the anti-parallelogram unit simplified as 2R-like mechanism, the construction methods of the loop-closed mechanism such as the 10R mechanism and the 12R mechanism are proposed. Secondly, according to the motion form and structural characteristics of the loop mechanism, combined with the characteristics of the side length of the polyhedron, deployable polyhedral mechanisms based on the loop-closed mechanism are proposed. Finally, the 3D model motion form of deployable polyhedral mechanism is given by the three-dimensional software.
Research on grid-connected stability control of full-power conversion wind turbine controlled by grid-side converter coupling voltage
Hao Wang, Guiying Liu, Hongbiao Wang, et al.
In the context of high proportion of wind power access, the stability of wind power as a power source has always been paid attention to, and the voltage stability of full-power conversion wind turbines is closely related to the control strategy of its converter control system. This paper proposes a new grid-side converter control strategy to maintain the stability of the grid-connected wind turbines. The contributions of this paper are: 1) Analyse the grid-side converter and establish its mathematical model to study the control of the wind turbine; 2) Add a voltage coupling controller to maintain the stability of the DC bus voltage; 3) Analyze the difference between the grid-connected voltage, current, active and reactive state variables before and after the wind turbine failure. The proposed control scheme for grid-side converter voltage coupling control will be tested in the full power conversion wind turbine set up in MATLAB/SIMULINK. The simulation results show the effectiveness and good dynamic performance of the scheme. The voltage oscillation has been alleviated to a large extent, and the DC bus voltage can basically be restored to its rated value.
Energy efficiency test and classification for escalator
Yuechao Song, Yingjie Liu, Shihong Chen, et al.
Escalator as special equipment is one of vertical transportation tools. In order to strengthen energy performance supervision, national standard commitment issued relative standard of energy efficiency test and classification for escalator. This paper introduces energy efficiency test and classification method for escalator. The main test procedure and evaluation criterion of energy efficiency for escalator are also clarified. Field test are carried out and test results are given and discussed to promote the application of this method.
Research on standardized assembly process method of aircraft cables
Junfeng Dai, Yin Xie
The current aircraft cables assembly process has problems such as difficulty in manual operation and inconvenient process methods, which affect the quality and efficiency of aircraft assembly. This article takes a certain aircraft as a representative. Starting from the actual requirements of aircraft cable assembly, through a detailed interpretation of the cable assembly process, the control points of each link in the assembly process are extracted, the cable laying assembly process is formulated, and the design technical indicators are determined. The method decomposes and displays theoretical standards in the form of standard work guides, allowing operators to intuitively feel the requirements of standardized work, and forms a set of cable assembly process technical requirements for standardized installation.
Safety evaluation and application for driving system of escalator
Yingjie Liu, Yuechao Song, Xingjun Wu, et al.
Escalators is very important vertical transportation tool, and its driving system operation characteristics are related to passenger safety. This paper studies the safety evaluation method of driving system of escalators in typical public places. Based on the risk assessment theory, the safety evaluation index of driving system escalators in public places is established, and the judgment of corresponding index and the risk rating method of driving system are given based on PHA-FMEA. According to the corresponding risk level, the corresponding escalator driving system safety improvement measures are given, and the corresponding application research is carried out based on this method.
Development of intelligent verification system for stacked kilogram weights
Jian Ma, Lin-lin Guo, Di Zhao, et al.
Unmanned verification of weights helps to improve the efficiency of weight verification and enhance the traceability of test data. This article started with the overall design of the intelligent verification system for stacked kilogram group weights, and proposed a software and hardware platform developed by relying on stacked kilogram group weights deep learning recognition and segmentation technology and kilogram group weight multi-modal sensing positioning technology to achieve fluorescent lighting. Intelligent verification of stacked kilogram weights. The system test experiment was carried out by simulating the construction of a stacked kilogram group weight stack, which verified the effectiveness and accuracy of the intelligent verification system. The verification time of a single weight instance was about 42s, which could meet the actual needs of the stack kilogram group weight verification process and realized the machine. The generation greatly improved the verification efficiency of stacked kilogram weights.
Production of entropy minimization of CO2 hydrogenation to light olefins unit reactor with linear phenomenological heat transfer law
Yajie Yu, Shaojun Xia, Ming Zhao
Based on the theory of finite-time thermodynamics(FTT), the model of the one-dimensional plug flow reactor for CO2 hydrogenation to light olefins unit with fully temperature controllable heat source temperature and the linear phenomenological heat transfer law is established and optimized. Under the condition of a given decene (C10H20) yield, the optimization objective is to minimize the production of entropy rate. The optimal process configuration for the minimum production of entropy of the reactor is obtained and compared with the reference reactor with constant heat source temperature and optimization results for the case with Newtonian heat transfer law. It shows that the production of entropy of the optimal reactor is reduced by 45.82% compared with the reference reactor. The optimal configuration of the heat source temperature has a rapid decrease firstly, then a rapid increase and a slow decrease finally. The heat transfer law is one of the important factors which affect the production of entropy minimization of the reactor. The obtained results in this paper have a certain theoretical guidance for the optimal design and operation of CO2 hydrogenation to light olefins unit reactor in engineering.
Test system design of container RFID tag based on virtual instrumentation
Shibo Xu, Jichun Li, Muhan Deng, et al.
In order to better meet the test requirements of container RFID tags and reduce the cost of test equipment, this paper proposes a test method for container RFID tags based on virtual instruments. And from two different aspects of laboratory testing and actual application scenarios, the software and hardware design of the container RFID test system has been implemented. Through this test system, all aspects of testing the quality and performance of container RFID tags will be supported.
Research on bearing health state prediction based on multidimensional information average convolutional neural network
Jiawen Yu, Hao Huang, Xiali Liu, et al.
Injection molding machine can shape all kinds of precise size, complex shape of plastic products, related to all aspects of people's life, such as the national defense field, civil fields such as electronic industry, daily use industry, medical industry and medical industry. Therefore, it is of great significance to establish a health prediction model for injection molding machine and carry out condition monitoring. Bearing is one of the most important parts in the rotating parts of the injection molding machine. Analysis of the health state of the bearing can reflect the performance state of the injection molding machine to a certain extent. Taking bearings as the research object, this paper introduces deep learning and information average convolutional neural network (AICNN), and proposes a health state prediction method of rotating equipment based on multi-feature variable fusion.
Unified admittance modeling of grid-connected converter and stability analysis for converter-grid system
Chunpeng Wang, Guorong Zhang, Runsheng Xie, et al.
Considering the actual situation, the converter-grid systems, including three-phase grid-connected converter and ac grid, mostly operate in the case of unbalance. However, most of the literature models and analyzes the balance situation, that is, the symmetric grid impedance and balanced three-phase grid voltage. In this paper, based on the harmonic transfer matrix (HTM) theory, a unified analytical expression of output admittance matrix of grid-connected converter is derived in detail, which can be used in both balance and unbalance cases. According to the relationship of interconnected system, the additional frequency components in unbalance conditions are uniformly equivalent to the frequency components existing in balance. Then the reduced-order output admittance model of the grid-connected converter and grid impedance model are established. Meanwhile, the correctness of the model is verified respectively. Based on the reduced-order model, the influencing factors of converter-grid systems under balanced and unbalanced conditions are analyzed.
Research on design and application of temporary line protection device in power system
Xuesong Zhao, Xu Feng, Weiying Deng
With the continuous expansion of the scale of China's power system, higher and higher requirements are put forward for the security and reliability of the power system. Therefore, this article is aimed at the current situation that most power supply companies in our country use bus tie protection as a temporary protection method for lines to be put into operation, and need to cooperate with a large number of switching operations and extremely error-prone. This paper designs a kind of temporary protection device which can play a good role in the process of line operation. The PSCAD/EMTDC simulation software is used to verify that the protection device designed in this paper can not only reduce the operation link, but also reduce the risk of secondary equipment. It is of great practical value to improve the efficiency and ensure the safety of the line operation process.
Design of output matching network for marine solar batteries based on embedded development technology
As a new generation of clean energy source, solar batteries have been widely used in shipbuilding industry. In order to maximize the economic benefits on the premise of ensuring safety of work in practical use, and to decide on the output strategy according to the working conditions in real time, this paper designed a low-cost output matching network system for marine solar batteries based on embedded development technology. This system used multi-sensors to judge its current working state through real-time information fusion, and controlled the charging and discharging switch circuit to realize reasonable allocation and storage of energy. This paper analyzed the composition of basic circuit control system, as well as the composition and working principle of the sensor system, designed hardware of charging and discharging control by adopting microprocessors based on STM32, and provided the implementation process of its software algorithm. The results show that the system can realize the safety monitoring and output energy control of marine solar batteries while working, and it can also maximize the energy utilization efficiency.
Temperature field analysis of cable joint
Zengtao Hua
In the power system, there are a large number of cable joints in the electrical transmission equipment. There are about one cable joint every 100 meters in the long-distance cable. A large number of cable joints are easy to cause internal and external faults. The fire caused by the problem of cable joints accounts for more than half of the total cable accidents. It is also a good choice to use insulation material between the cable and the environment, and to inject high insulation and good heat conduction material between the measuring point and the joint. This situation is mainly suitable for cable components with small heat capacity. For electrical equipment in normal operation, the greater the temperature difference between inside and outside the cable, the greater the resistance at the joint. It can be understood that the warning signal of cable joint failure can be replaced by the temperature of the cable.
The effect of exhaust gas recirculation on engine combustion
Li-wei Han, Guo-xiang Lu, Jian-qiang Ning, et al.
Facing the goals of carbon emission peak target and carbon neutral, exhaust gas recirculation (EGR) technology will be one of the widely used engine technologies. It is significant to study the effect of exhaust gas recirculation on engine combustion and performance. In this paper, some related experiments were investigated on a certain 1.5L engine. The EGR temperature has a certain effect on the engine intake temperature. With the increase of EGR temperature, the fuel consumption rate increases, but the increase range is not large. When the EGR temperature increases from 60℃ to 100℃, the fuel consumption rate increases by 0.5%. With the increase of EGR temperature, the knocking intensity gradually increases, which can results a post-correction angle of ignition advance angle, and a very slight increase of the combustion duration.
Testing device and method of escalator stopping distance based on infrared technology
Zhongxing Li, Guojian Huang, Haixia Ma, et al.
At present, the test of the stopping distance of the escalator mainly relies on the marking method, which is completed manually, and the error is large. In order to improve the efficiency and accuracy of detection, an idea and method for escalator stopping distance measurement based on infrared distance test and Hall induction current test technology is provided. First, it analyzes the braking principle and braking process of the escalator, adopts infrared-based ranging technology, and increases the test frequency according to the algorithm to achieve the effect of real-time testing. During the test, the position of the escalator during the entire braking process is dynamically tracked. Combined with the current sensor to capture the change of the current, through the extraction and processing of the two signals, the accurate stopping distance can be calculated. The test results show that the repeat error of the stopping distance measured by this method is 1.7%, which is reduced to 1/5 of the original, and the test time is shortened to 1/2 of the original.
A fault analysis of ammunition supply system for a certain type of vehicle
Haibing Zhang, Aihua Zhu, Hongkai Wang, et al.
This dissertation mainly employs the ammunition supply and transportation system as the research object, sets up the fault tree structure graph of unable to supply ammunition under bottom event, and takes the qualitative and quantitative analysis methods to analyse the fault cause of the bottom event of top event so as to lay maintenance foundation for the examination and maintenance during the operation procedure.
The branch current method zinc oxide arrester power frequency parameter field test method and its system and test
Han Wang
In order to ensure the safe operation of power system, it is necessary to carry out preventive test on MOA regularly. At present, the traditional test method is complex in operation, low in efficiency and high in risk, which cannot meet the development needs of modern power system. Based on the existing test methods, the critical operating voltage and leakage current of metal oxide arrester are tested. A set of test system is designed and the field test is carried out. The maximum error between the test results and the manufacturer's data is less than 5%, which proves the reliability of the system. The test results show that the method and system have the characteristics of simple operation, high security, and can obtain multiple data groups at one time, which can greatly simplify the operation process and improve the test precision. The system has the advantages of simple structure, low cost and good industrial application value, which provides a new direction for the detection of lightning arrester.
Application of spacecraft manufacturing equipment management system
Xiaoxu Zhao
Modern equipment management relies on wireless communication, network connectivity and other technologies to record and collect device state data, and through the application of sensors and Internet of Things technology for automatic control, and even intelligent control. Because of the requirement of information security, wireless network, sensor technology, Internet of Things could not be applied in these enterprises which like aerospace industry and other military industry. In addition,it is difficult to supervise and manage the technological equipment which are high-valued, long-serviced and widespread. In this paper, spacecraft manufacturing equipment management system (SMEMS) is established, and an innovative means of combining handheld terminals with production conditions is designed. The work carried out in this paper solves the problem of the production and collection of offline equipment status data, and opens the way to the management system and the state of the production site. The methods tried in this paper can provide reference for the equipment management of other military enterprises.
Development of new wave-eliminating interceptor in the tunnel engineering
Chengfei Fan, Yongsheng Chai, Fan Yang, et al.
A new wave-eliminating interceptor was developed, so as to disturb and obstruct the explosion shock wave flow field, so that the explosion shock wave was rapidly attenuated. Based on structure design, installation design and material selection of interceptor, the numerical simulation, whose interceptor was restricted explosion shock wave, was realized. Then the strength check of interceptor was carried out, and the dynamic response law of the interceptor was revealed. In this paper, the new wave-eliminating interceptor was machined. And there were lots of advantages, such as high wavecutting rate, simple structure, low cost and convenient installation. It would be beneficial to the application in the new construction and reconstruction of tunnel engineering.
The intelligent anti-mistake system for combination of primary and secondary equipment
Yongxin Chen, Zuowei Wang, Hong Zhang, et al.
The technical measures of secondary equipment status acquisition and secondary equipment calibration rules in substation are insufficient, and there is a lack of anti-mistake locking function between primary equipment and secondary equipment. In the process of primary equipment operation, there are risks of secondary equipment operating error. In this paper, an intelligent anti-mistake system for combination of primary and secondary equipment is proposed to ensure the safety and control of the entire operation.
An integrated on-board charger (OBC) with high power density and efficiency for electric vehicle
Ce Ji, Xing Zhang, Tengfei Wang, et al.
Compared with the discrete structure of traditional On-Board Chargers (OBC) and Low-voltage DC Converters (LDC), this paper proposes an isolated three-port OBC topology, which uses a multi-winding transformer to achieve magnetic coupling between three ports, which effectively improves power density. Functionally, it realizes the functional integration of OBC and LDC, which can meet the requirements of use under a variety of working conditions. This paper reasonably designed the control strategy under each mode, and finally verified the feasibility of the design scheme based on MATLAB/simulink.
Research on PEMFC and its interface converter
Guobang Ban, Wenjie Wang, Hui Huang, et al.
With the continuous expansion of energy storage market, proton exchange membrane fuel cell (PEMFC) technology using hydrogen as fuel has attracted more and more attention. However, the market of hydrogen fuel cell still faces many difficulties, and the design methods of the corresponding converter are still immature. In this paper, the topology and control strategy of DC/DC converter for PEMFC are discussed. It is found in this paper that the converter of hydrogen fuel cell is similar to the conventional converter in general, but special design is needed to deal with the dynamic response in order to meet the operation requirements and prolong the life of the converter.
Arc contacts ablation state assessment method based on machine learning multiple linear regression
Yijun Liu, Daopin Chen, Muxin Diao, et al.
SF6 circuit breakers are widely used in power systems to ensure the safe and stable operation of power systems. This paper considers circuit breaker condition-based maintenance and proposes a method for evaluating the ablation state of arc contacts based on machine learning multiple linear regression algorithm. The dynamic resistance measurement(DRM) is used to obtain the dynamic contact resistance-travel curves characterizing the full life state of the arc contacts, and the relevant diagnostic parameters are extracted from the curve as model inputs. The radial ablation coefficient, the axial ablation coefficient and the number of remaining closing times are used to comprehensively characterize the ablation state of arc contacts. The model solves multiple linear regression equation by gradient descent method and adopts the RMSE value to evaluate the model prediction results. The results show that model predictions are relatively consistent with the experimental results, which can provide a reference for condition maintenance of circuit breakers.
Study on the fire-resistance of UHV converter station
Jianli Yao, Jun Ji, Weimiao Zhao, et al.
The plugging of the valve hall of the UHV converter station is an important barrier to prevent the fire from spreading to the valve hall, and the heating curve of hydrocarbon fire should be adopted for defense. The fire resistance test results of the rock wool composite aluminum silicate plate under the hydrocarbon fire heating curve show that the plug has good heat insulation and complete performance and meets the three-hour fire resistance requirements. It is a fire protection structure for the valve side casing of the converter station. The retrofit provides a solution. The study of the microscopic mechanism of the disassembled plugging material shows that the phase change reaction of structural rock wool under hydrocarbon fire is the main reason for its sintering.
Calculation and analysis on transmission performance of slotted permanent magnetic coupler
The permanent magnetic couple is a non-contact transmission device with higher transmission efficiency than a traditional rigid transmission device. Slotting the copper conductor disc on the permanent magnetic coupler can further improve the transmission performance. This paper proposes an optimization calculation model for the slotted permanent magnetic coupler, uses ANSYS Maxwell to simulate and verifies the model to improve the transmission performance. The value of magnet pairs and the slots are 6 and 35 respectively; then we simulate output torque when the slot ratio changes from 0.5 to 0.9. The simulation results verify the accuracy of the optimization model. This paper obtains the optimization scheme of the slotted permanent magnetic coupler under different parameters. The calculation model can guide the determination of a slotted permanent magnetic coupler, which is of great significance to improve the efficiency of the transmission system.
Design and motion research of self-rotating double-body negative pressure wall climbing robot
Lichao Cao, Fan Yu, Xiaoguang Liu, et al.
Negative pressure wall-climbing robot only can work on a single flat wall due to its special working principle, and there are problems such as limited wall transition ability and poor overall obstacle avoidance. In order to solve the above problems, the author designed and produced a double-body negative pressure wall climbing robot with self-rotation function. Firstly, the mechanical structure and control system of the robot was designed, secondly the movement of the robot wall transition and obstacle avoidance was analyzed, and finally the feasibility of the overall design was verified through experimental tests. The results revealed that the double-body negative pressure wall-climbing robot had the ability of wall transition and self-rotation to avoid obstacles flexibly, which greatly improved the range of motion and application.
Intelligent industrial vortex flowmeter based on MSP430
Zheming Xu, Bin Ma, Xiaotian Fu, et al.
At present, vortex flowmeter still commonly exists two problems that the signal cannot be detected in the low flow rate so that the range ratio is limited, and high-power consumption cannot be applied to the harsh environment of the industrial site. With the design principles of low power consumption and integration, this paper designed a low-power vortex signal processing system based on the MSP430. The low-power operational amplifier TLV2254 is used to implement the preamplifier circuit to complete the charge/voltage conversion, amplification, filtering, shaping and other pre-processing of the signal output from the eddy street sensor. The low-cost and low-power-consumption MSP430F149 is selected as the control core for the signal acquisition and calculation circuit to complete the acquisition, analysis, and calculation of the signal, and control the LCD display of the calculation results. The software part mainly completes the acquisition of vortex signal, spectrum analysis, frequency calculation and display functions. In the laboratory flow test results show that the vortex flowmeter effectively extends the lower limit of the flow signal measurement, expand the range ratio at 5Hz, reduce power consumption makes the instrument work longer about 213 days in FFT mode. Through the combination of software and hardware design such as power supply monitoring, watchdog and software filtering, the anti-interference and safety of the system have also been greatly improved, which can be well applied to the field of industrial instrumentation.
A visual auxiliary inventory counting system for the automated stereoscopic warehouse
Xiao-dong Tu, Jing-yu Zha
The automated Stereoscopic warehouses are widely used in the logistics industry, they are featured as achieving dense storage, making full use of space. However, the denser storage makes inventory counting harder. The inventory check procedure usually take days. To cope with the difficulty, a Visual auxiliary inventory counting system is proposed. It is fixed on a stacker, with RGBD camera for visual perception. Through data assembling and date comparing, the system finds the appearance changed (compared to the time that right after stocking) bins in the inventory counting procedure. The staff only have to take minutes to count a very small part of the bins manually instead of checking thousands of bins. Experiments show that our system operates precisely and significantly efficiency.
Wind power prediction of CNN-LSTM network model based on unsupervised algorithm processing
Hongtao Shi, Mingren Guan, Maosheng Ding
Wind power prediction is of great significance to the safe and stable operation of power systems and the optimal allocation of energy. Aiming at the huge amount of related data in wind power prediction, a wind power prediction model based on unsupervised algorithm-CNN-LSTM is proposed. Firstly, an unsupervised algorithm is used to preprocess wind power-related data, which solves the problems of large redundancy and slow convergence of training data in traditional forecasting model; therefore the algorithm can be applied to multi-dimensional and large-scale data; then, convolution cyclic neural network model uses convolution neural network to perform multi-layer convolution , and pool stacking calculation on wind power, wind speed, wind direction and other data to extract the characteristic map of wind power data, and takes the characteristic map information as the input information of long-term and short-term memory neural network. Finally, an example is to verify the proposed method.
Gearbox fault diagnosis based on deep convolution generative adversarial network
Yiqiang Jiang, Chen He, Li Sun, et al.
The existing gearbox fault diagnosis models often need a lot of fault data and corresponding tags to complete the model training, but the actual fault data is often less and unevenly distributed. Aiming at the situation that the gearbox fault data is scarce and unevenly distributed, this paper proposes a fault diagnosis method based on the Deep Convolution Generative Adversarial Network (DCGAN). First, the original vibration signals collected in the early stage are processed through data processing to form a sample data set and input into the DCGAN model for confrontation training, and virtual samples with real sample characteristics are generated to expand the sample data set. Then, the convolution neural network model is constructed to complete the fault diagnosis and get the results. The results show that the model trained by this method is more accurate when generating a large amount of data, and the diagnostic effect is significantly better.
Key technology of estimating earthwork volume of riprap project by cross-section survey
Wentao Huang, Guotao Dai, Hao Zhou, et al.
In order to quickly estimate the volume of earthwork along the main embankment, this experiment measured the river bottom elevation and riprap surface elevation of the main embankment riprap in Huangtian section of Nanxi River. Based on the network RTK Technology of zjcors, this paper collected the three-dimensional coordinates of the river bank measure points, Echotrac.MKⅢ dual frequency sounder and Haida ocean survey software are used to measure the water depth along the river bank path, and the full spectrum chirp technology is used to measure the silt thickness. Finally, the trapezoidal section method is used to calculate the earthwork volume of the detection data. The results show that the estimation of the depth of each coastal section and the volume of earthwork obtained from this test is reasonable and applicable.
A quick capacity estimation method for Li-ion battery combining equivalent circuit model and Bayesian network
Yifan Wang, Shiyu Liu, Pengfei Kou, et al.
State of health (SOH) estimation for power battery is critical for reliable and safe operation of electric vehicles (EVs). In this paper, we propose a novel SOH estimation method combing equivalent circuit model (ECM) and Bayesian network. Firstly, a Bayesian network for SOH estimation is constructed according to existing knowledge about battery degradation. Then variables in Bayesian network is estimated by applying recursive least square algorithm with forgetting factor on first-order RC ECM. Afterwards, the model is trained to obtain the conditional probability distribution for each variable in Bayesian network. Finally, the effectiveness and accuracy of the model is verified using battery aging data.
Analysis of anti-wave characteristics of a new type of solar farming platform
Yanwei Liu, Yang You
This paper proposes a new type of marine aquaculture platform design scheme, which adopts the breeding concept of "fishing and light complementation", that is, building a photovoltaic system on the water surface to form a development model of "power generation at the top and fish breeding at the bottom". The breeding platform adopts a small water surface line anti-wave structure, solar power generation system as a power source, intelligent feeding and breeding of large yellow croaker. Numerical simulations are used to study the hydrodynamic characteristics of the offshore aquaculture platform under 13 wave-current combinations.
Multi-objective optimization of hybrid energy storage in micro-grid based on wavelet packet decomposition and neural network
Zhongchao Wu, Mingxing Zhu, Qi Li, et al.
A multi-objective optimization design model of distributed micro-grid for local wind and solar energy consumption is proposed. Firstly, in view of the smooth grid connection of high permeability renewable micro sources, the wind output power is decomposed by wavelet packet frequency in different decomposition frequency bands, and the corresponding power primary command is obtained. Combining with power primary command and the configuration of hybrid energy storage system (Hess), the smoothness index after suppression is calculated, using multilayer feed forward neural network, the neural network model of micro-grid design parameters—smoothness index is trained to design parameters of micro network. Then, the K/P/Q — neural network economic cost mathematical model was established by using genetic algorithm to solve the problems of cycle life and charge and discharge power consumption investment cost of lead-carbon battery, so as to realize the multi-objective optimization design of micro-grid and minimize the investment cost. Finally, Matlab is used to verify the feasibility and effectiveness of the proposed model in the evaluation of the smoothness index and the optimal allocation of capacity of the micro-grid.
Design of peanut sowing spraying film covering machine
Mingming Liu, Qiang Li, Jikai Jin, et al.
Peanut in hilly and mountainous areas, not suitable for large-scale mechanized operations, the traditional artificial planting operations are low efficiency, labor intensity and other problems. this paper designs a peanut sowing spraying film covering machine. In this paper, the whole scheme of peanut seeding spraying and film covering machine is designed, and the key components such as ditching device, seeding device, spraying device and film covering device are designed and calculated in detail. Field tests show that the peanut sowing spray coating machine designed by this method can flexibly carry out sowing operations in hilly and mountainous areas, and achieve sowing efficiency of 0.26-0.33 hectare/h, which can effectively improve the efficiency of farmers, save operating time and reduce labor.