bluuebunny/crossref_metadata_2025_split huggingface dataset:
Path planning for UAV based on improved dynamic step RRT algorithm
Authors: Xiong Jing , Duan Xiaokun 
Published: August 2021

Abstract
Path planning is an important problem in the field of unmanned aerial vehicles (UAVs). However, it is inefficient for many rapidly-exploring random tree (RRT) based methods to rapidly find a feasible solution in a complex environment. To solve the path planning problem for the UVA in a complex environment, an improved dynamic step size RRT algorithm combined with a new path length control strategy is proposed. Firstly, the algorithm adopts a biased-goal sampling strategy to guide the growth of the tree, and an expansion direction constraint strategy is adopted to limit the expansion direction of the tree. Secondly, an improved dynamic step size strategy is proposed to speed up the path searching process. Thirdly, a path length constraint strategy is designed, which is used to constrain the path length during the searching process for a solution. Finally, simulation results demonstrate that the proposed method achieves improvement in both computational time and the path quality.
Research status of hydraulic oil evaluation technology
Authors: Lu Changbo , Li Hua , Zhang Bin , Wang Mengyi , Xiong Chunhua 
Published: August 2021

Abstract
Hydraulic oil has an important influence on hydraulic system, and the research on its evaluation technology can provide technical support for the rational use of oil in hydraulic system. The status of hydraulic oil evaluation technology research at home and abroad is reviewed, including the physicochemical properties and comprehensive performance indexes of the oil. Combined with military requirements, it is found that the low-temperature cold start performance of hydraulic oil is more critical, but there is less research in this area. Therefore, this paper builds a cold start performance evaluation bench and test method to provide technical support for military oil use.
Feasibility study of swash plate plunger pump system in drainage gas recovery process
Authors: Xiong Wei , Zhang Shengli , Wang Lina , Zhang Xu , Ma Jixiang , Zeng Kang , Tian Jianchao , Wang Meng , Li Ran , Jing Zhiqiang , Wang Quansheng , Zhu Tong , Wang Liya , Liu Jingzhi , Hao Li , Xu Shuanglong , Duan Ran 
Published: August 2021

Abstract
With the continuous development of Sulige gas field, the formation pressure has gradually dropped, problems that liquid loading and water flooding affects the normal production of gas wells have gradually appeared. Drainage gas recovery delays the decline of gas field production to some extent, but the stable production of gas wells with large water production has become a field problem. Therefore, the pneumatic swash plate plunger pump system that does not need external power equipment but has large displacement and is easy to manage is studied. It has become another weapon to prolong the blowout period of gas wells.
Influence of guide vane angle of circulating hot blast stove sleeve on temperature field and flow field
Authors: Xiao Ru , Zhang Jiangyong , Jiao Shengjie 
Published: August 2021

Abstract
In order to improve the heating efficiency and uniformity of the hot air circulation heater, a three-dimensional model of a hot blast stove of hot in-place recycling hot air circulating heater was established, based on the finite element method and CFD software ANSYS, the influence of the guide vane angle of the circulating hot blast stove sleeve on the temperature field and flow field of hot blast stove and air distribution pipe was studied by numerical simulation. The results show that the guide vane angle of the hot blast stove sleeve affects the temperature distribution at different positions of the air distribution pipe, has less influence on the internal temperature field of the hot blast stove, and has greater influence on the temperature distribution of the air distribution pipe. With the increase of the guide vane angle of the hot blast stove sleeve, the velocity and flow path of the circulating hot air in the hot blast stove sleeve increases, which improves the hot air distribution uniformity of the heating device. When the guide vane angle of hot blast stove sleeve is 45°, the hot air transverse distribution uniformity of heating device is the best.
Thermal design and simulation of monitoring payload on manned spacecraft
Authors: Zhai Ruiqiong , Yang Xiaoning , Jiang Lixiang , Yi Zhong , Liu Yenan , Li Jian , Li Xiyuan , Lin Boying , Wang Junfeng 
Published: August 2021

Abstract
Discharge monitor is a kind of primary payload monitor loaded on the manned spacecraft in the Low Earth Orbit, which is designed for monitoring the secondary discharge problem on the solar array. The issue of integrated electronic device heat dissipation is the key for normal operation supporting. In this study, the integral payload is simulated by finite element method, through structure modeling, based on the theory of heat conduction and heat radiation. In the result, under the measures of adjusting the layout of the electronic devices, coating the circuit board with copper, and black anodization for the case, the payload could definitely meet the needs of the heat dissipation in the extreme conditions, survive safely and functionalize perfectly in the orbit, at least from the angle of thermal design.
Mobility analysis of hybrid-driven ten-bar mechanism
Authors: Wang Limin , Wang Ying 
Published: August 2021

Abstract
For a new mechanism, it should be able to move continuously according to the predetermined motion law. Each bar of the mechanism should meet certain size conditions. In this paper, a new type of three degree of freedom ten-bar mechanism with symmetrical structure is proposed. According to the motion requirement, the condition of crank existence is analyzed. The size of the mechanism is determined. The possible limit position space of this mechanism is analyzed. It lays a theoretical foundation for the application of the mechanism.
Research on anti-pilot contamination in massive MIMO
Authors: Yuan Qin , Li Lihua , Xia Weixia , Zhu Gailin , Zhu Xishun , Wu Jianhua 
Published: August 2021

Abstract
In order for the pre-coding technology to suppress the influence of pilot contamination, a hybrid pre-coding scheme is proposed in this paper by combining a full-digital pre-coding technology and an analog beamforming in the context of current massive MIMO. Simulation results show that the proposed pre-coding scheme effectively suppresses the pilot contamination while reducing the system structure complexity and ensuring the system’s basic performance, which is of important significance in practical communication applications.
Research on a projectile-borne measuring apparatus for electromagnetic launcher
Authors: Cao Ronggang , Hu Xueyi , Dong Erwa , Ma Xiao , Zhou Yu 
Published: August 2021

Abstract
In order to evaluate the electromagnetic launch effectiveness and understand the corrosion damage of the electromagnetic launcher, it is necessary to master the magnetic field data in the bore. At present, there is no related research on the measurement of the bore magnetic field of the electromagnetic launcher. Therefore, a small-scale projectile-borne measuring apparatus based on B-dot probe is developed in this paper. This apparatus uses FPGA as the core. Through the static magnetic field measurement experiment, the data of the induced voltage and the induced magnetic field can be obtained. The projectile-borne magnetic field measuring apparatus designed in this paper can accurately measure the bore magnetic field of the electromagnetic launcher, which lays the foundation for further analysis of the influence of the electromagnetic field in the bore on the launch effect and investigation of the corrosion damage of the electromagnetic launcher.
Research on PD source successive approximation positioning method based on multi sample information
Authors: Zhu Qingdong , Zhu Wenbing , Gao Zhixin , Zhu Mengzhao 
Published: August 2021

Abstract
Ultra High Frequency (UHF) detection technology is widely used in Partial Discharge (PD) detection and positioning of electrical equipment. However, how to achieve accurate and reliable fault localization based on UHF PD is an urgent problem to be solved. In this paper, the multi-samples of PD are calculated by the successive approximation method and the optimization function is established by using the linear spatial relationship between the initial value and the sensors. The particle swarm optimization (PSO) is exploited to search for the minimum value of function, and the optimal result is obtained by cyclic calculation. The optimal PD source position determined by this way has higher accuracy, solving the problem of strong dispersion and large error in PD location by a single sample. The positioning error is reduced from tens of centimetres of the single sample to few centimetres, which is fewer than the results calculated by the average method. In addition, it is found that the positioning precision becomes higher as the number of samples selected for optimize calculation (i.e. m) decreases.
Simulation study on genetic algorithm control of hydrogen fuel cell gas supply system
Authors: Cheng Rong , Chen Jing , Cheng Nanding , Xiao Chun 
Published: August 2021

Abstract
Fuel cell as a new clean energy, its advantages of high efficiency, low emission and low noise have attracted the attention of domestic and foreign governments and scholars. To this end, based on the requirement analysis of the hydrogen fuel cell gas supply system, this paper focuses on the genetic algorithm optimization PID control strategy of the hydrogen fuel cell gas supply system. The simulation model is built on the Matlab/Simulink platform and compared with the conventional PID algorithm in the model. The simulation results show that the comprehensive index of PID control algorithm optimized by genetic algorithm is better than that of conventional PID algorithm, which proves the improvement effect of the proposed control strategy on the dynamic response of the gas supply system.
Research status and development trend of PCS
Authors: Wang Xudong , Zhou Weigui , Wang Weishan , Wang Mengyi , Wang Changfu 
Published: August 2021

Abstract
Due to the shortage of conventional energy and serious environmental pollution, new energy (NE), such as wind energy, solar energy, biomass energy, etc. is getting more and more attention. However, the output power of NE is unstable. Energy storage is the most effective way to solve the problem of NE applications. The power conversion system (PCS) determines the output power quality and dynamic characteristics of the energy storage system. This paper reviews the development and application of PCS, conducts a detailed study of its working principle, topology, and key technologies. The main index system of PCS is established by consulting the relevant standards, and the requirements and detection methods of the main indexes are pointed out. This work provides a scientific basis for the selection of PCS. At the end of the paper, summarizes and prospects on PCS.
Research on measures suppressing high frequency transient overvoltage in offshore wind farms
Authors: Li Sisi , Fang Chun’en , Pan Lin , Duan Jiaojiao , Chen Junping 
Published: August 2021

Abstract
A large number of different types of cables, wind turbines, transformers and vacuum circuit breakers (VCBs) are used in power collecting system of offshore wind farms (OWFs). Due to the phenomenon of traveling wave refraction and reflection in cable collector system, transient overvoltage with high amplitude and high steepness will be generated when reignition phenomenon occurs in frequent operation of vacuum circuit breakers on wind turbines, which will cause serious damage to transformers, the problem of overcurrent is also becoming more and more serious. Therefore, through the electromagnetic transient simulation software of ATP-EMTP, a single-phase model of VCB switching-off transformer in offshore wind farm is built to study the influence of the separation speed of contacts of vacuum circuit breaker, high-frequency arc quenching capability and arching time on overvoltage. Then, the medium voltage cable collector system of OWF is built. Installing ferrite ring near the VCB or on the high-voltage side of transformer can suppress high frequency transient overvoltage. The results show that the high frequency transient overvoltage generated by offshore wind farm can be well suppressed after the installation of overvoltage protection device.
Simulation research on phase selection control algorithm of a four-phase interleaved parallel Boost converter
Authors: Zhang Meng , Chen Jing , Li Zhihua , Xiao Chun 
Published: August 2021

Abstract
In order to increase the rated power of the DC/DC converter, the interleaved parallel connection is widely used. Although the interleaved and parallel Boost converters can increase the operating power of the system, at the same time, it has the advantages of smaller system output current ripple and can reduce the stress of switching devices, but when the system is running in low power mode, due to the use of multi-phase Boost, the increase in loss makes the conversion efficiency of the system lower. A phase selection control algorithm is proposed in this paper, by which the conversion efficiency of multi-phase interleaved parallel Boost converters can be effectively improved. Finally, the feasibility of the phase selection control algorithm designed is verified through simulation in this paper.
Staggered parallel asymmetric boost converter based on coupled inductor
Authors: Zhu Longji , Guo Qiang 
Published: August 2021

Abstract
Aiming at the problems of insufficient voltage gain, excessive voltage stress and current stress of switches in DC boost converters, an interleaved parallel asymmetric boost converter is proposed. The circuit adopts interleaved parallel boost converters, coupled inductors and switched capacitors to form an asymmetric boost converter structure, so that the voltage gain of the converter is more than twice that of the traditional coupled inductor boost converter; and it adopts the passive clamp circuit to eliminate the switch voltage spike at the moment of turn-off, so that the voltage stress and current stress on the switch devices are reduced. The simulation results show that the boost converter obtains high voltage gain and high efficiency, and is suitable for applications with large DC boost ratio.
IEEE 1901.1 Power Line Communication electromagnetic emission study
Authors: Amaro Nuno , Saragoça João , Cartaxo Ricardo , Yang Wei , Yi Ren 
Published: August 2021

Abstract
IEEE 1901.1 Standard for Medium Frequency (less than 12 MHz) Power Line Communications for Smart Grid Applications was officially released in 2018. This standard expands the possible applications of Power Line Carriers communications by using a medium frequency technology, allowing for a higher bandwidth and bit rates compared to the current industrially used solutions. As the standard operates below a frequency of 12 MHz, and constituting a new solution in this area, it is fundamental to evaluate electromagnetic emissions and evaluate possible electromagnetic disturbances. In this paper, we pre-sent a methodology to measure electromagnetic emissions of IEEE1901.1 compatible devices. This methodology is then used to measure real emissions from two different IEEE compliant modules from two different manufacturers, including central coordinator and station devices.
Research on improved time difference estimation algorithm based on fourth-order cumulant in UHF PD location
Authors: Zhu Wenbing , Xu Wei , Zhou Jiabin , Xu Ran , Yi Feng 
Published: August 2021

Abstract
Ultra-high frequency (UHF) detection technology is a fast-developing method for partial discharge (PD) diagnosis of electrical equipment in recent years. Extracting accurate time difference is the priority for PD location in electrical equipment using UHF technology. An improved time difference estimation algorithm based on fourth-order cumulants was first proposed in this article. It mainly included the following two steps, that is using the “correlation-shift-superposition” transformation method to process multiple samples collected from a PD source at first, and then utilizing the statistical characteristics of the fourth-order cumulant to calculate the time difference. In addition, the accuracy and stability of the improved algorithm and the other three common methods were compared. The calculation results show that the improved time difference estimation algorithm based on the fourth-order cumulant can obtain a more accurate and stable time difference than the other three methods. Improved time difference estimation algorithm based on fourth-order cumulant can approximately meet the requirements for reliable location of PD sources.
Multi-view based template matching method for surface defect detection of circuit board
Authors: Zhou Junyu , Liu Yaowen , Zhang Xueliang , Yang Zhiming 
Published: August 2021

Abstract
In order to avoid defects (e.g. dust, scratch, static electricity) caused by manual detection, this research proposes a non-contact defect detection approach for circuit board through use of template matching method. In the proposed approach, images of both circuit board to be detected and circuit board selected as template are obtained respectively from multiple views. Then defect index (DI) of each view is constructed based on corresponding matching results between the image to be detected and the template image. Finally, total defect index is obtained by integrating all DI from multiple views, which can characterize the existence of defects in the circuit board (e.g. lack or wrong installation of components). The proposed approach is experimentally investigated to detect two surface defects on a circuit board. Results show that the two defects can be accurately detected with no false alarm by use the proposed method.
Comparative study of the synchronous control for rigidly coupled electro-motors
Authors: Liu Tong , Chen Cheng , Ye Beifa , Chen Yuxi 
Published: August 2021

Abstract
Multiple electro-motors rigidly coupled by multi-points gear meshing is of a typical driving structure, and the synchronous control between parallel motors is the key issue about system stability and performance. Firstly, the drooping control is introduced to modify traditional speed parallel control (SPC) method; classical torque master-slave control (TMSC) using soft control parameter is also proposed as contrast. Subsequently, the basic principle of vector control with rotor flux orientation is described; the non-linear time-varying gear dynamics at the unbalanced pinion-gear meshing stage are also studied. Based on the mathematic analysis, simulation models under three different control methods are established in Simulink, and are comparatively studied against backlash, contact ratio and motor parameter deviations between multiple chains. Finally, SPC with drooping control (SPCD) and soft TMSC (STMSC) are applied on a test rig. The simulation and experimental results show that, SPC, SPCD and STMSC separately has advantages in speed tracking, system stability and torque synchronization, and should be used according to specific preference.
Implementation and testing of a conformance platform for IEEE 1901.1 Power Line Communication Standard
Authors: Amaro Nuno , Saragoça João , Cartaxo Ricardo , Yang Wei , Yi Ren 
Published: August 2021

Abstract
IEEE 1901.1 Standard for Medium Frequency (less than 12 MHz) Power Line Communications for Smart Grid Applications was officially released on 2018. This standard brings new possibilities for power line communications, as the used frequency range allows for broader band and higher bit rates when compared to other PLC communication standards. In this scope, this paper presents a conformance platform that allows testing compliance of devices implementing the standard. This conformance-testing platform is then used to test the station and concentrator devices from three different manufacturers, using the data link layer tests as one example, highlighting the capabilities of the platform and simultaneously evaluating the current status of development of these devices (with regards to standard compliance). Results of these tests are also included.
The development of the online detection network system of coal mine safety instrument and meter
Authors: Tao Xinya , Tian Muling , Liu Xiqing 
Published: August 2021

Abstract
As the main equipment that directly reflects the concentration of various flammable, explosive, toxic and harmful gases in the working environment of mines, the coal mine gas sensors are widely used in coal mine safety monitoring and supervision systems. However, these sensors cannot accurately display the concentration of the detected gas due to problems such as zero and span drift of the catalytic element. Therefore, regular testing is required according to coal mine safety regulations. In this paper, the network system of coal mine safety instrument testing center is designed, and a network on-line testing system of coal mine safety instrument’s input, inspection, output, certification and finance is established, which integrates the network server, company LAN, upper computer automatic analysis, lower computer real-time processing and takes barcode as the identification. It realizes the network operation of sensor storage, waiting for inspection, verification, sending and achieves the goal of improving efficiency and reducing labor intensity.
Design of flyback power supply of DC equipment in PV power plant
Authors: Wang Guoliang , Shi Junhai , Chen Yuchen , Yan Weiwu 
Published: August 2021

Abstract
In photovoltaic (PV) grid-connected power generation systems, the needs of low-voltage DC power supply for equipment in PV power plant areas are common. This article provides a design of wide-range high-input voltage flyback power supply. Firstly, the needs of the input voltage range are analysed, and the power supply indexes are defined. Then, the design of the power supply and the transformer circuit are given. The prototype trial results are also given at the last. The results show that the designed power supply meets the requirements of equipment in PV power plant.
Recent developments in load model parameter identification via ambient PMU signal
Authors: Guo Siyuan , Jiang Yunchen , Chen Daojun 
Published: August 2021

Abstract
Load modelling has a significant impact on operation mode arrangement, transient stability analysis, small disturbance stability calculation and other aspects in power system. It is an important basis and issue for the decision-making of dispatching operation department. As a novel research field of measurement-based identification method, load model parameter identification via ambient PMU signal has gained some developments. This article reviews the current research status of ambient data-based load parameter identification, outlines its basic principle and typical framework, and expounds three technical routes. By summarizing the characteristics of various methods, the future research direction is prospected.