2017 Vol. 43, No. 8

Display Method:
Design of automatic control system of circular low speed wind tunnel and its measurement uncertainty evaluatio
CHU Weizhong
2017, 43(8): 1-5. doi: 10.13272/j.issn.1671-251x.2017.08.001
Abstract:
In order to satisfy demands of rapid, accurate, automatic detection of mine-used wind speed sensor and wind speed impact test of mine-used gas sensor, an automatic control system of circular low speed wind tunnel was designed. The system uses PLC as main control unit, and adopts PID control module to control frequency converter fastly according to relationship between wind speed and static pressure difference and through automatic collection and calculation of atmospheric pressure, wind temperature, static pressure difference, so as to realize automatic output of wind speed by controlling change of rotate speed of motor. The uncertainty evaluation was analyzed including uniformity, stability and turbulence intensity of pitot tube, automatic control system, wind tunnel wind speed in the measuring process for detecting GFY15 mine-used wind speed sensor as example.The evaluation results show that the automatic control system can meet needs of automatic detection for mine-used wind speed sensor.
Design of mine-used drilling pipe replacing device and its control system
LI Xiaopeng, QIAO Jie, YAO Yafeng
2017, 43(8): 6-10. doi: 10.13272/j.issn.1671-251x.2017.08.002
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Abstract:
In view of problems of difficulties and security risks in operation of loading and unloading of drilling pipe caused by high hole position and large hole opening angle in current coal mine tunnel drilling construction, a mine-used drilling pipe replacing device and its control system were designed. The drilling pipe replacing device is used with active drilling pipe of power head of drilling rig and the hold, to achieve loading and unloading of drilling pipe in the middle. The control system takes mine intrinsically safe and flameproof hydraulic controller as the core, and drives control proportional solenoid valve and commutation solenoid valve by PWM signal and switching signal respectively, so as to adjust the expansion and contraction speed of the cylinder. The cylinder telescopic length signal driven by proportional solenoid valve is fed back to controller by magnetostrictive sensor to form closed-loop control of the cylinder telescopic position. The test results show that the mine-used drilling pipe replacing device for drilling rig can match the existing type of drilling rig, and meet the needs of automatic loading and unloading of drilling pipe in the large-height or large-angle sidetrack drilling construction, thus improves the drilling construction efficiency and the safety of the drilling pipe replacing operation.
Memory attitude monitoring method for hydraulic support based on grey theory
WANG Yafei, WANG Xuewen, XIE Jiacheng, YANG Zhaojian
2017, 43(8): 11-14. doi: 10.13272/j.issn.1671-251x.2017.08.003
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Abstract:
Existing hydraulic support monitoring methods can only monitor single support without fusion analysis of monitoring data of united hydraulic supports and have low utilization ratio of monitoring data. For above problems, a memory attitude monitoring method for hydraulic support based on grey theory was proposed. The method calculates predictive value of related memory attitude parameters according to monitored value of memory attitude of hydraulic support by use of grey theory. It can predict attitude of the next hydraulic support according to actual attitude of previous hydraulic supports in the same monitoring cycle, so as to realize horizontal cycle monitoring, and also predict attitude of a hydraulic support in the next monitoring cycle according to actual attitude of the hydraulic support in the last few cycles, so as to realize longitudinal cycle monitoring. The support height of hydraulic support monitoring test results show that predictive value of memory attitude of hydraulic support is similar to the actual value, which verifies the validity of the method.
Research on intelligent mine-used material distribution system
WEI Feng, ZHAO Yunlong
2017, 43(8): 15-19. doi: 10.13272/j.issn.1671-251x.2017.08.004
Abstract:
In order to solve problems of cumbersome in material receiving and low efficiency of traditional "library staff - user" mode by use of document during process of coal mine material distribution, an intelligent mine-used material distribution system based on "reserve warehouse - intelligent cabinet - users" mode was designed. The system uses intelligent terminal cabinet as delivery station of material distribution, and realizes remote communication and control of the intelligent terminal cabinet by use of the system management platform based on Web technology. Meanwhile, the system has data interface to connect coal mine enterprises resource planning system. The application result shows the system can improve efficiency and accuracy of coal mine material distribution and reduce personnel cost.
Research on support technology of rail haulage roadway of mining area
LIN Na, SUN Luo
2017, 43(8): 19-24. doi: 10.13272/j.issn.1671-251x.2017.08.005
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Abstract:
In view of problems of simple indicator selection, big calculation error, complicated testing process existed in current bolt support design methods, stability classification of surrounding rock of roadway was determined by field investigation and laboratory mechanical test taking rail haulage roadway of No.3 north wing quasi mining area coal seam in a coal mine as research background, and different support schemes were put forward. Supporting effect of different support schemes were analyzed through numerical simulation analysis, and conclusions were obtained that supporting method of "anchor cable + anchor bolt + anchor net + steel strip" is the most reasonable supporting scheme of all, it has the minimum scope of plastic deformation of roadway surrounding rock, roof and floor of roadway and displacement of two side coal-walls are the minimum. The field test results also indicated that the surrounding rock deformation is small, the supporting control effect is better when use the supporting method of "anchor cable + anchor bolt + anchor net + steel strip".
Rectification scheme of electromagnetic compatibility radiation emission for mine-used personnel location system
WANG Shuqiang
2017, 43(8): 25-30. doi: 10.13272/j.issn.1671-251x.2017.08.006
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Abstract:
According to requirement of electromagnetic compatibility in European Norm EN 301 489-1, mine-used personnel location system must pass radiation emission test when it is applied in foreign countries. For the requirement, radiation emission test for mine-used personnel location system was carried out, and causes of radiation noise was analyzed. The following rectification scheme was put forward: for the radiation emission caused by the clock signal, shorten the length of clock signal line during PCB routing, reduce the number of vias, increase the alignment width and line spacing, and laying ground wire on both sides to shield, so as to reduce return area of clock line; for different clock circuits, low-pass filter, common mode suppression and other measures were adopted to reduce radiation signal transmission. Tests results show that the maximum peak frequency power of the personnel location system after the rectification is 13.086 dB lower than requirement of EN 55032 standard CLASS A and 3.086 dB lower than the requirement of EN 55032 standard CLASS B, which can meet the export requirements.
Comparative analysis of series fault arc detection methods
GUO Fengyi, BILGUUN Baatar, REN Xue, FANG Zhipeng, ZHANG Hongbo
2017, 43(8): 31-36. doi: 10.13272/j.issn.1671-251x.2017.08.007
Abstract:
For uncertainty of line fault location, current series fault arc detection methods are mainly based on current signal analysis. By comparing current waveforms before and after series arc fault under different loads, characteristics and regularities of series fault arc current were obtained. Taking current signal of series fault arc as research object, three kinds of series fault arc detection methods were introduced which use Hilbert-Huang transform, information entropy and short-time Fourier transform and wavelet approximate entropy and support vector machine respectively. Extraction processes of fault arc feature with different detection methods were summarized, and advantages and disadvantages of the three methods were compared. A view was pointed out that the detection method based on Hilbert-Huang transform and the one based on information entropy and short-time Fourier transform can effectively extract time-frequency characteristics of fault arc, and series fault arc can be identified according to proper threshold of time-frequency spectrum amplitude with low accuracy and real-time performance. The detection method based on wavelet approximate entropy and support vector machine can directly extract approximate entropy as input of support vector machine to detect series fault arc with higher accuracy and real-time performance, which is more suitable for coal mine.
Present situation and development direction of navigation technology of boom-type roadheader
TIAN Yuan
2017, 43(8): 37-43. doi: 10.13272/j.issn.1671-251x.2017.08.008
Abstract:
Problems of navigation and positioning of boom-type roadheader and its particularity and mathematical description were described. Status of technology of electro-optical navigation and positioning and pose detection, technology of inertial navigation, and navigation and positioning technology based on multi-information fusion were analyzed in details. The conclusions were obtained: the technology of electro-optical navigation is mature and has high precision, but there are serious environmental adaptability problems in coal mine application; the inertial navigation technology has strong adaptability, high accuracy of pose detection, but has poor precision of long-term positioning; the technology based on fusions of multi-information and multi-sensor, which combining electro-optical navigation and inertial navigation, may be the better way to solve the problem of spatial position and pose detection of boom-type roadheader, the key to realization of information fusion is to solve measuring benchmarking issues brought from multi-information and multi-sensor, and more robust fusion algorithm is needed.
Research on infrared radiation characteristics of pre-cracked coal sample under loaded breaking
CHENG Fuqi, LI Zhonghui, YIN Shan, WEI Yang, SUN Yinghao
2017, 43(8): 44-49. doi: 10.13272/j.issn.1671-251x.2017.08.009
Abstract:
Uniaxial compression test was conducted on pre-cracked coal sample, and infrared radiation temperature and its change rule of the pre-cracked coal sample under loaded breaking were researched. The experimental results show that infrared radiation temperature curve will mutate in process of loaded breaking of the pre-cracked coal sample, and the infrared radiation temperatures of the pre-cracked coal samples with different angles will suddenly increase during main rupture. The mutation rate of infrared radiation temperature increases first and then decreases with increase of pre-cracked angle during main rupture, and the mutation rate of infrared radiation temperature of the pre-cracked coal sample with 45° is the largest. The change rule of infrared radiation of the pre-cracked coal sample is closely related to load and pre-crack, which can reflect internal rupture of macroscopic defective coal sample under load.
Video mosaic algorithm based on improved random sample consensus algorithm
CHENG Deqiang, LI Hang, HUANG Xiaoli, TU Yilei, YOU Dalei
2017, 43(8): 50-55. doi: 10.13272/j.issn.1671-251x.2017.08.010
Abstract:
In order to solve problems of seam and ghosting in real-time video mosaics, a video mosaic algorithm based on improved random sample consenus (RANSAC) algorithm was proposed. Firstly, speed-up robust features algorithm is used to extract feature points and find matching feature points in the overlapping area of binocular camera. Then, the improved RANSAC algorithm is adopted to remove the mismatched point pairs and obtain the optimal homography matrix. Finally, the pixels in overlapping areas are processed by dynamic fusion. The experiment results show that using the proposed algorithm can effectively eliminate the seam and ghosting in the video overlapping area, and also ensure real-time performance of the video mosaic system.
Fault simulation analysis of constant deceleration braking system of mine hoist
LI Juanjuan, HU Liang, MENG Guoying, XIE Guangming, WANG Aiming, WANG Shuai, JIA Yifan
2017, 43(8): 55-60. doi: 10.13272/j.issn.1671-251x.2017.08.011
Abstract:
Taking E141A constant deceleration braking system in JKMD 4.5×4 mine hoist as research object, working principle of the constant deceleration braking system was analyzed. A simulation model of the constant deceleration braking system was built and reliability of the simulation model was verified by theoretical calculation. Typical faults such as spring stiffness decrease, friction factor of brake shoe decrease and brake leakage were simulated. The simulation results show that performance degradation of main components cannot immediately cause failure of the braking system, but can cause system performance degradation such as braking system pressure degradation, braker clearance smaller or bigger, etc. The braking system performance degradation with a certain degree will cause faults such as unsatisfactory braking deceleration, no braker clearance, too large braker clearance, too long idle motion time, etc.
Research on temperature field of permanent magnet in disc-type speed-regulation magnetic coupler
GUO Yongcun, FANG Cheng, WANG Pengyu, CHEN Jiankang
2017, 43(8): 61-66. doi: 10.13272/j.issn.1671-251x.2017.08.012
Abstract:
In view of problems that temperature of permanent magnet is too high and easy to fail when disc-type speed-regulation magnetic coupler with high power is running, a magnetic circuit method was used to make theoretical derivation for eddy-current loss of conductor rotor, and finite element software was used to carry out research on steady-state temperature field for permanent magnet of magnetic coupler under condition of high power and high load. The research results show that with increasing of slip, temperature of the permanent magnet of the magnetic coupler increases; with decreasing of air gap distance of the magnetic coupler, the maximum temperature of the permanent magnet gradually rises. When slip of the magnetic coupler is in 180 r/min range, the air gap is no less than 18 mm, temperature of the permanent magnet will remain below 55 ℃,the maximum magnetic energy area and remanence of the permanent magnet are almost unaffected, and the normal and efficient operation of the magnetic coupler can be ensured. When the magnetic coupler is in working state of high power and high load, the air gap distance has a significant influence on the temperature state of the permanent magnet. When the slip is 180 r/min, the air gap is less than 15 mm, the temperature of the permanent magnet would rise sharply. When the air gap is reduced to 3 mm, the maximum temperature of the permanent magnet will reach over 180 ℃, and the magnetic remanence will be close to 20% compared with the room temperature, and the maximum energy product will decrease by about 45%. The research results have a guiding significant meaning for temperature field analysis of the high power magnetic coupler.
Detection method of joint twitching of steel cord conveyor belt
HAN Xiandai, CAO Xuehong, JIAO Liangbao
2017, 43(8): 67-71. doi: 10.13272/j.issn.1671-251x.2017.08.013
Abstract:
For low accuracy and poor adaptability existed in current detection methods of joint twitching of steel cord conveyor belt, a detection method of joint twitching of steel cord conveyor belt based on X-ray image was proposed. Firstly, X-ray image is enhanced by use of image enhancement method based on Retinex theory. Then joint edge is detected by Sobel edge detection operator so as to extract centroid of the joint edge as joint point, and the joint points divided into different levels are fitted linearly. Finally, joints of current image and reference image are matched according to number of steel wire rope between adjacent joints, and distances from the matching joints to the corresponding fitting lines are compared. Joint twitching is detected according to whether the distance difference is larger than a certain threshold value. The test results show that the method can detect joint twitching accurately with high joint recognition rate.
Design of real-time tracking monitoring and early warning system for coal mine groundwater
XING Zhenguo, DU Wenfeng, LIANG Zhe, HU Jinkui
2017, 43(8): 72-75. doi: 10.13272/j.issn.1671-251x.2017.08.014
Abstract:
In order to improve hydrological monitoring of coal mine groundwater and water disaster prediction level, a real-time tracking monitoring and early warning system for coal mine groundwater based on intelligent water level meter was designed. The system uses metal probes of a water sensor to judge whether the intelligent water level meter is in aquifer, and downs the intelligent water level meter into water automatically when water level drops below the intelligent water lever meter, so as to avoid pseudo data. The system obtains water pressure data through a hydraulic sensor, and uses upper computer to fit and analyze the data, so as to calculate water level. The test results show that the system can run stably and early warn water level mutation of aquifer in 5 s, whose measurement error of water level is not more than 2 cm.
Fault phase selection of mine power supply system based on frequency distribution theory
YU Qun, CHEN Zhihui, HE Ziyua
2017, 43(8): 76-82. doi: 10.13272/j.issn.1671-251x.2017.08.015
Abstract:
In view of the problem of ineffective selection of asymmetric mine neutral point ungrounded system while high resistance grounding occurs, a fault phase selection of mine power supply system based on frequency distribution theory was proposed. Each phase voltage after the fault of the first 1/2 frequency cycle was collected, and extended Prony algorithm was used to fit the collected data, then the frequency distribution theory was used to process the sampled voltage of each phase. On the basis, frequency distributions of voltage of each phase were obtained by Bessel formula, and the fault phase was selected by comparing the magnitude of the frequency distribution. The results of Matlab simulation and adaptability analysis show that the proposed method has high accuracy and is applicable to fault conditions of low impedance grounding and high impedance grounding. It has strong adaptability to noise interference and data window length, and is not affected by sampling frequency and group distance.
Design of novel intrinsically safe power supply with "ia" grade
YU Zhixue, FANG Xupeng, ZHAO Yang
2017, 43(8): 83-86. doi: 10.13272/j.issn.1671-251x.2017.08.016
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Abstract:
According to working condition of mine-used power supply in coal mine underground, novel intrinsically safe power supply with "ia" grade was designed. The power supply uses a fully enclosed AC-DC module to eliminate special flameproof enclosure, and has over-voltage protection circuit of dual redundancy and over-current protection circuit of three redundancy. The experimental results show there is no spark when the power supply load is short circuited under the conditions of no fault, one counting fault and two counting faults, which realizes intrinsic safety.
Application of comprehensive early warning system of coal and gas outburst
ZHU Zhen, WU Baolei, MENG Jie, TAO Yunqi, WANG Feng
2017, 43(8): 87-90. doi: 10.13272/j.issn.1671-251x.2017.08.017
Abstract:
In view of problem that conventional coal and gas outburst forecasting technology used a single forecast indicator and cannot considering outburst risk factors synthetically, the paper designed a comprehensive early warning system of coal and gas outburst, and gave structure and functions of the system, and introduced application processes of the system taking Longshan Coal Mine as an example. The practical application results show that the early warning system can effectively detect dangerous area and realize early warning of coal and gas outburst.
Prediction and analysis of gas emission in advancing process of stope working face
HUANG Hejiang
2017, 43(8): 90-93. doi: 10.13272/j.issn.1671-251x.2017.08.018
Abstract:
The data of existing gas emission prediction methods of stop working face are mostly based on gas concentration sequence of single sensor in stope working face, and these methods can not record position of monitoring point in process of continuous advancement of the working face.In view of above problems, a method that used BP neural network model to predict gas emission in the working face was proposed, which was based on data of gas concentration sequence data of monitoring point of sensor and actual advance distance on stope working face. The method uses gas source identification method of the working face to analyze variation law of gas emission of in goaf and coal wall respectively; and uses BP neural network prediction method to predict average daily gas emission combining with characteristic values of variation law of gas emission of in goaf and coal wall. The example application verifies correctness of the method.
Design of coal mine hazard safety management system
DUAN Ruiwei
2017, 43(8): 94-97. doi: 10.13272/j.issn.1671-251x.2017.08.019
Abstract:
In view of problems of incomplete application of hazard identification result in daily safety management, incomprehensive safety status evaluation of hazard and lacking of overall planning in coal mine hazard safety management, a design scheme of coal mine hazard safety management system was proposed, and design objectives, overall framework, key technologies and main functions of the system were introduced. The system adopts browser/server architecture and Internet of things technology, takes hazard factor library which is formed from hazard identification and evaluation result as core, recombines hazard safety management and daily safety management to realize effective fusion, so as to provide a comprehensive management means for hazard safety management.
Design of mine wireless sensor network and its applicatio
TONG Zhansheng, WANG Chunming, LI Kai
2017, 43(8): 98-100. doi: 10.13272/j.issn.1671-251x.2017.08.020
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Abstract:
In view of problems of small bandwidth, low transmission rate and complicated wiring of current fieldbus communication network in coal mine underground, a design scheme of mine wireless sensor network was proposed. The mine wireless sensor network, which is based on TD-LTE technology, can access wireless terminal equipment through wireless base station and existing equipment and system in fieldbus communication network through customer premise equipment, so as to realize regional data collection. The application results show that the mine wireless sensor network meets requirements of mine Internet of things with large bandwidth, long transmission distance, stable data transmission and high real-time performance.