2017 Vol. 43, No. 4

Display Method:
Design of control system of electric traction shearer oriented automatic working face
ZHANG Xuhui, YAO Chuang, LIU Zhiming, ZHAO Youjun
2017, 43(4): 1-5. doi: 10.13272/j.issn.1671-251x.2017.04.001
Abstract:
In view of status that existing control system of shearer is difficult to meet demand of automation control of working face in terms of real-time data collection and processing, remote monitoring and integrated intelligent control algorithm, a control system of electric traction shearer oriented automatic working face was designed. The system adopts double DSP architecture, and uses powerful data processing ability and rich peripherals of DSP to complete data collection and calculation of working condition of shearer, and real-time communication with peripheral equipments. The system realizes functions of automatic cutting control of shearer, coal mining technological change and remote monitoring, which can provide technical support for automation mining of shearer.
Design of lithium battery management system for explosion-proof electric vehicle
LI Qiwei
2017, 43(4): 5-9. doi: 10.13272/j.issn.1671-251x.2017.04.002
Abstract:
A lithium battery management system for explosion-proof electric vehicle was designed according to GB 3836-2010 and Power safety technical requirements of mine-used flameproof and intrinsic safety type lithium-ion battery(trail). The system takes STM32F105VCT7 main controller and LTC6804-2 battery management chip as cores on the basis of RT-Thread real-time operation system, and uses passive battery equalization scheme to equalize battery voltage. The test result shows that the maximum voltage difference among twelve lithium batteries is 0.237 V and 0.025 V separately before and after applying the system, which has good effect of battery voltage equalization.
Design of lubricating oil temperature monitoring system of emulsion pump
FU Xiang, WANG Ranfeng, YUAN Jicheng, DONG Zhiyong
2017, 43(4): 10-13. doi: 10.13272/j.issn.1671-251x.2017.04.003
Abstract:
In view of problem that current lubricating oil temperature monitoring method of emulsion pump can only identify oil temperature overrunning but cannot monitor abnormal temperature rise, an oil temperature monitoring method based on statistical process control was proposed according to statistical properties of oil temperature process data, and an implementation scheme of exponentially weighted moving average control chart applied to oil temperature monitoring was given. On the basis of the scheme, an oil temperature monitoring system of emulsion pump was designed. The practical application results show that the system can monitor oil temperature of emulsion pump in real time and send out fault alarm accurately.
Research status of coal minie rescue robot and its development directio
YOU Shaoze, ZHU Hua, ZHAO Yong, CHEN Chang
2017, 43(4): 14-18. doi: 10.13272/j.issn.1671-251x.2017.04.004
Abstract:
Development background of coal mine rescue robot was introduced, and research status and application situation of coal mine rescue robot at home and abroad were summarized. Some technical problems about robots taking part in coal mine rescue work were analyzed and pointed out, such as poor terrain adaptability, large size, short effective working distance, defective intelligence, low stability and so on. Technical development direction of coal mine rescue robot was put forward, namely bionic mechanical structure, efficient energy, lightweight materials, intelligent machine control, collaborative rescue and modular design. It was also pointed out that the future development of coal mine rescue robot would be accompanied with common development of various technologies.
Research on variation law of secondary stress on working face of Guotun Coal Mine
JIANG Zilong, CHEN Wenlong, LIU Youjian
2017, 43(4): 18-21. doi: 10.13272/j.issn.1671-251x.2017.04.005
Abstract:
For deformation and failure situation of roadway on 1304 working face of Guotun Coal Mine, the secondary stress of the working face was measured. Three monitoring drills were constructed at one point of the roadway on 1304 working face, and four HI sensors were set in the boreholes at 150 m away from the working face, which were used to monitor the secondary stress variation generated by rock mass at different positions influenced by mining. The field test results show that peak position of advancing abutment pressure is at about 6.9 m ahead of the working face, and stress concentration factor is about 2. In order to avoid the peak value of the advancing abutment pressure, the size of small coal pillar should be less than 6.9 m. Vertical stress of the laneway’s side is higher, which is 56.7 MPa. Therefore, the roadway should be timely supported to improve carrying capacity of the small coal pillar.
Research on electronic image stabilization algorithm based on subsample gray-scale projectio
FAN Yeping, GUO Zheng, ZHANG Rui
2017, 43(4): 22-27. doi: 10.13272/j.issn.1671-251x.2017.04.006
Abstract:
In order to stabilize dithering images obtained by mine vehicle-mounted recording system fast and accurately, an electronic image stabilization algorithm based on subsample gray-scale projection was proposed. Firstly, the image is processed by histogram equalization to improve image contrast. In order to reduce computation amount of the algorithm and weaken impact of local moving objects, the image is multi-resolution layered by the method of subsample, and the adjacent two frames of the low resolution image and its predetermined sub-regions are selected for gray-scale projection operation. The global motion vector is obtained by weighted summing process of the operation results. Finally, the image is compensated by adaptive adjacent frame compensation method according to compensation amount obtained by Kalman filtering. The experimental results show that the proposed algorithm is superior to traditional gray-scale projection algorithm in terms of accuracy and computation time, and can achieve long time continuous image stabilization.
Research on extraction of image gray information and texture features of coal and gangue image
TAN Chunchao, YANG Jieming
2017, 43(4): 27-31. doi: 10.13272/j.issn.1671-251x.2017.04.007
Abstract:
In view of problems of low identification accuracy and efficiency existed in most recognition method of coal and gangue image which only used gray mean and gray variance, an extraction method of gray information and texture features of coal and gangue image was proposed. The representative feature parameters such as gray average, smoothness and energy, contrast, correlation, entropy of gray co-occurrence matrix are extracted, which are taken as the important basis for identification of coal and gangue. Matlab simulation results show that the gray information and the texture feature can well describe characteristics of the coal and the gangue image, which can provide an important reference for automatic identification and separation of coal and gangue.
Research on pore fractal characteristics of outburst coal seam in Guizhou province
XU Lin, YUAN Mei, YANG Mengmeng, XU Shiqing, WANG Yuli, LI Chuang
2017, 43(4): 32-36. doi: 10.13272/j.issn.1671-251x.2017.04.008
Abstract:
Coal samples of six outburst coal seams in coal-rich areas in Guizhou province were taken as research objects to analyze size grade of pore, fractal dimension, fractal characteristics and relationship between the fractal characteristics and gas adsorption or coal permeability by use of liquid nitrogen adsorption experiment and mercury intrusion experiment. The experimental results show that pores of the coal samples with different grades have good fractal characteristics, which can show porosity and pore distribution characteristics. The fractal dimension can be used to quantitatively analyze pore characteristics of coal samples. There is a positive correlation between the fractal dimension of micro pore of the coal samples and gas adsorption value. Gas adsorption capacity of coal samples in different coals is quite different. The fractal dimension of small pore reflects simple pore structures of coal samples and pore similarity among coal samples. The fractal dimensions of medium pore, large pore, pore fracture and micro fracture show that pore distribution trend of each coal sample is similar. Pores with some size grades develop badly, so measure for increasing the permeability of coal seam are needed to improve gas drainage effect.
Fault diagnosis of mine ventilator based on improved BP neural network
SUN Huiying, LIN Zhongpeng, HUANG Can, CHEN Peng
2017, 43(4): 37-41. doi: 10.13272/j.issn.1671-251x.2017.04.009
Abstract:
In view of characteristics of complicated correlation of mine ventilator failure and symptom, a fault diagnosis method using BP neural network optimized by dynamic adaptation cuckoo search algorithm was proposed. The optimal initial parameters of neural network are solved by using global search ability of dynamic adaptation cuckoo search algorithm. Then, the BP neural network is trained to obtain the final fault diagnosis model. The example analysis results show that the method can effectively achieve fault diagnosis of mine ventilator and has the characteristics of fast convergence and high precision, and the diagnosis accuracy of the test sample is 92.5%.
Reliability analysis of braking system of hoister considering relevance
WANG Min, WU Bing, WANG Juan
2017, 43(4): 41-45. doi: 10.13272/j.issn.1671-251x.2017.04.010
Abstract:
Reliability function model of braking system of hoister was analyzed taking braking force failure as specific study object. Fault chain of the braking force failure was obtained by correlation analysis, and total failure rate considering relevance was calculated combined with independent failure rate and correlation coefficient. Time interval distributions of braking force failure in two cases of considering relevance and not considering relevance were analyzed, and linear fitting results show that the time interval distribution of braking force failure considering relevance is more consistent with Weibull distribution model. The experimental results show that the error range of theoretical and practical values of failure rate is 1.33%~3.25%, which verifies correctness of the reliability function model.
Electromagnetic wave multipath channel model based on image method in mine tunnel
YAO Shanhua
2017, 43(4): 46-49. doi: 10.13272/j.issn.1671-251x.2017.04.011
Abstract:
In view of complicated electromagnetic wave propagation environment in mine tunnel, a multipath channel model of electromagnetic wave propagation in mine tunnel was established by use of image method. In the paper, calculation methods of total propagation distance, incidence angle and reflecting angle of three-dimensional helix ray, and expressions of total receiving power and transmission loss were presented. The simulation results show that attenuation of electromagnetic wave field intensity is larger near transmitting antenna with fast fading phenomena, which verify the model can predict electromagnetic wave field intensity distribution in tunnel accurately.
Research on compound current control strategy based on LCL type active power filter
GAO Yunguang, SONG Jiancheng, ZHENG Lijun, JIANG Fayang, TIAN Feiyan
2017, 43(4): 49-54. doi: 10.13272/j.issn.1671-251x.2017.04.012
Abstract:
In view of contradiction between high steady state accuracy and fast dynamic response of traditional current control strategy, a novel compound current control strategy based on LCL type active power filter was proposed. The control strategy combines proportional integral control and repetitive control, the PI controller is used to ensure fast dynamic response, and further compensate control model to the stable system, which has good control characteristics in low frequency range; the repetitive controller is used to correct resonance peak and PI-inner-loop inherent phase lag of LCL filter, so as to realize fast tracking and high precision compensation on harmonic current of the power grid. The experiment results show that total harmonic distortion of the grid current is significantly reduced by compensating of shunt active power filter and the single-cycle fast response is achieved when the load changes, which verifies the compound current control strategy is effective.
Fault diagnosis method of distribution network with distributed generatio
CHENG Xuezhen, LIN Xiaoxiao, ZHU Chunhua, LEI Qian, CHEN Qiang
2017, 43(4): 55-59. doi: 10.13272/j.issn.1671-251x.2017.04.013
Abstract:
It can change magnitude and direction of fault current of distributed network after distributed generation was connected to power distribution system, which made fault diagnosis of power distribution system complicated. For the above problem, a fault diagnosis method of distribution network based on power direction criterion and Petri net was proposed. The method uses uploading and measured double fault information to realize redundant error correcting, and can accurately and quickly diagnose fault areas, so as to improve fault diagnosis accuracy and fault tolerance of distribution system with distributed generation. At the same time, the method uses unique graphic description and parallel processing ability of Petri nets to ensure universality of fault location model and rapidity of fault diagnosis. The example simulation results verify feasibility and effectiveness of the proposed method.
Online monitoring method of mine-used high voltage cable insulatio
ZHANG Xiao, WANG Yanwen, ZHAO Yongmei, HOU Linan, BAI Shuju
2017, 43(4): 60-63. doi: 10.13272/j.issn.1671-251x.2017.04.014
Abstract:
In order to monitor insulation condition of mine-used high voltage cable in real time, an online monitoring method of mine-used high voltage cable insulation based on wide area measurement system(WAMS) was proposed. In the method, real-time voltage and current of cable ends are obtained synchronously by use of WAMS, and insulation resistance and equivalent capacitance of cable are derived through establishment of equivalent circuit model of cable to ground, so as to realize dynamic monitoring of cable insulation condition. The simulation results show that measurement error of the method decreases with increase of cable insulation deterioration, which meets precision requirement of online monitoring of mine-used high voltage cable insulation.
Design of EMI filter for high-power explosion-proof inverter
LIU Xiangxin, TAN Guojun, HU Zihao, ZHANG Yucheng, FENG Anbo, MA Liang, WANG Kai
2017, 43(4): 64-67. doi: 10.13272/j.issn.1671-251x.2017.04.015
Abstract:
Generation mechanism of EMI in high-power explosion-proof inverter was analyzed, and design method of an EMI filter for high-power explosion-proof inverter was proposed. The EMI filter uses "P" matching network structure based on a single LC filter, and realizes impedance matching of the explosion-proof inverter in the case of impedance mismatching, so as to improve EMI filtering effect. A 1 MW/1 140 V explosion-proof inverter was tested to verify validity of the EMI filter.
A quasi-Z-source boost DC-DC converter
FANG Xupeng, MA Bolong, DONG Zhaolong, GUO Jiuhong, GAO Guanzhong
2017, 43(4): 68-71. doi: 10.13272/j.issn.1671-251x.2017.04.016
Abstract:
For problems of traditional boost converter including limited boost ability and high capacitor voltage stress, a boost DC-DC converter was proposed which used two quasi-Z-source networks in cascade. Working process of the converter was analyzed, and expressions of step-up ratio and capacitor voltage stress were derived. Compared with traditional Z-source boost converter, the quasi-Z-source converter can realize larger step-up ratio with small duty cycle, and has lower capacitor voltage stress under the same step-up ratio. The simulation and experimental results verify validity of the theoretical analysis.
Control strategy of harmonic suppression of micro-grid based on virtual harmonic impedance
XU Ruidong, ZHOU Jianyong, WANG Boya, YU Zhiwei, WANG Linge, CAO Liru, WU Chenli
2017, 43(4): 72-76. doi: 10.13272/j.issn.1671-251x.2017.04.017
Abstract:
In view of problem of harmonic pollution caused by nonlinear loads in micro-grid, a control strategy of harmonic suppression of micro-grid based on virtual harmonic impedance was proposed. The principle of droop control is analyzed, and harmonic suppression model of two inverters running in parallel is given. The harmonic current is detected by SOGI model and voltage zero-steady-state error control is achieved by improved PR quasi-proportional resonant controller based on SOGI model. The virtual harmonic impedance control strategy and its implementation are analyzed. The simulation and experimental results verify correctness and reliability of the control strategy.
Connectivity fault diagnosis method of motor and its applicatio
MA Hailong, WANG Jun
2017, 43(4): 77-81. doi: 10.13272/j.issn.1671-251x.2017.04.018
Abstract:
In view of problem that connectivity fault feature of motor was identified difficultly, on the basis of mathematic models and spectrum characteristic of motor connectivity faults represented by misalignment, looseness and base stiffness, empirical mode decomposition method was proposed to process vibration signal of motor. Diagnosis result is gotten according to fault feature frequency. The field application results verify effectiveness of the method.
Harmonic detection device based on comb filter and subgroup algorithm
DAI Chaofan, DENG Xiaoxiang, CUI Chengyao, LIU Baotong, SUN Wei
2017, 43(4): 81-85. doi: 10.13272/j.issn.1671-251x.2017.04.019
Abstract:
:In view of problems of bad accuracy and real-time existed in harmonic and inter-harmonic detection algorithm, a harmonic and inter-harmonic detection algorithm based on comb filter and subgroup idea was proposed, and a harmonic monitoring device based on the algorithm was designed. Firstly, the device uses the comb filter to separate harmonic and inter-harmonics from original signal effectively. Then, the device uses inter-harmonic subgroup algorithm to calculate inter-harmonic component of the separated signal, and uses original signal component to minus the inter-harmonic component to reconstruct of sampled sequences. Finally, the device adopts harmonic subgroup algorithm to calculate the harmonic component, so as to realize high precision detection of harmonic. Test results verify that the device has high detection accuracy.
Cooperative control of high-efficient and rapid excavation system
HU Shouxi
2017, 43(4): 86-88. doi: 10.13272/j.issn.1671-251x.2017.04.020
Abstract:
Cooperative control of high-efficient and rapid excavation system need to realize cooperative walking among digging equipment, crushing equipment and support equipment and linkage control of transportation system on the basis of technologies of digging, support and transportation in working face. According to cooperative control requirement of high-efficient and rapid excavation system, electronic control system of each equipment in the system transmits data through wireless communication device, so as to realize linkage control of transportation system, linkage control between flexible belt conveyor and walking type self advancing conveyor tail and cooperative operation between digging-bolting machine and crusher, and achieve coordinated, continuous, high-efficient and safe operation of each equipment.