工矿自动化

Research of Design of Coal Mine Emergency Rescue Communication System Based on Wireless Mesh Network

HUO Zhen-long, GU Ju

2012, 38(11): 1-4.

<Abstract>(59) <PDF>(8)

Abstract:
In view of problems of low definition of voice caused by oxygen device, absence of video information, lack of monitoring and transmitting functions of environment parameters existed in coal mine emergency rescue communication system at present, the paper proposed a scheme of coal mine emergency rescue communication system based on wireless Mesh network. It briefly introduced networking mode and general structure of the system, and gave design approach of primary devices in the system after analyzing principle and topology of the wireless Mesh. It also discussed key technique difficulties such as QoS guarantee, dynamic routing for wireless Mesh network, service admittance and control, seamless mobility of media stream and so on, and put forward their solutions. Practical application shows that the system can offer voice and video communication functions among ground headquarter, underground headquarter and underground rescue technicians, and real-time monitor and display environment parameters at headquarter.

Research of Support System Platform of Intrinsic Safety of Coal Mine

HE Yao-yi

2012, 38(11): 5-8.

<Abstract>(26) <PDF>(5)

Abstract:
In allusion to the grim actuality of safety situation of coal mine in China and the problems existed in construction of domestic information system of coal mine safety management, the paper proposed the establishment of support system platform of intrinsic safety of coal mine with open system architecture, which is accorded with management status of domestic coal mine and can reflect modern informatization theories and methods of coal mine management. The platform is based on theory of intrinsic safety, and takes risk pre-control as the core and the intrinsic safety of human, machine, ring and management as main line. The platform realizes identification and investigation of major dangerous source, predictive analysis and classification evaluation, which minimizes the risk of accidents. The platform uses measures of visualization training, position responsibilities, institution and measure management combined with related equipments to improve safety knowledge and skills of the staff, make them have a good safety awareness, and ensure the effective implementation of various safety measures, so as to achieve intrinsically safe management of coal mine.

Improvement Scheme of Switchover Control System without Blowing-out of Mine Main Ventilator

MENG Lin-shan, MA Xiao-ping, LI Quan-bao

2012, 38(11): 9-10.

<Abstract>(42) <PDF>(7)

Abstract:
For the problem that industrial computer is easy to crash after a certain number of years in switchover control system without blowing-out of mine main ventilator, the paper proposed the solution of connecting sensor to the switch, and using multiple industrial computers to read data at the same time. For the problem that RS485 signal output by temperature logging devices and electrical parameters acquisition modules cannot directly access the switch, the paper proposed two improvement schemes, namely adding serial servers or RS485 modules of PLC. It analyzed advantages and disadvantages of the schemes and ultimately chose the scheme of adding RS485 module of PLC. The practical application shows that the improved system runs well and achieves the desired effect.

Design of Dot-matrix Drawing Software Used in Mine LED Electronic Display Board

DING Rui-qi, HE Yao-yi, WANG Yong, ZHANG Wei-guo, YAN Zhao-zhen, SU Lin

2012, 38(11): 11-13.

<Abstract>(47) <PDF>(7)

Abstract:
For problems of inaccurate drawing and poor visibility of mine LED electronic display board using vector technical to draw graphics, the paper proposed a design scheme of dot-matrix drawing software which can be applied in different types of electronic display boards, and introduced overall design and graying steps of BMP image of the software. The dot-matrix drawing software achieves functions of WYSIWYG drawing, text and dot-matrix conversion, BMP pictures import/conversion, ICO icons import/export, analog display and external common interface. Comparison result shows that both the original graphics and their actual display effects of the graphics drawn by the dot-matrix drawing software are significantly better than the graphics drawn by vector technical.

Research of Metering Technology of Pipeline Gas Flow of Coal Mine

LI Tao

2012, 38(11): 14-17.

<Abstract>(91) <PDF>(22)

Abstract:
Development status of metering technology of pipeline gas flow of coal mine was introduced, and advantages and disadvantages of orifice flowmeter, vortex flowmeter, Pitot tube flowmeter, swirlmeter and V-cone flowmeter were analyzed. Solutions were proposed for the impact of impurities in gas and changes of gas concentration on metering accuracy of gas flow. V-cone flowmeter was advised for main pipe, stem pipe and branch pipe, and inserted flowmeter with multiple-point sampling was advised for confluent pipe and evaluation units. A viewpoint was pointed out that the metering of pipeline gas flow of coal mine should select appropriate flowmeter according to different field conditions, working conditions and metering needs.

Study of Gas Distribution in Return Airway of Working Face and Discussion of Layout of Gas Monitoring Points

LI Zhong-hui, FAN Xin-ting, SONG Xiao-yan

2012, 38(11): 17-20.

<Abstract>(43) <PDF>(6)

Abstract:
Gas concentrations of different sections in return airway of working face were tested, and the gas distribution contours of roadway section were made for studying gas concentration distribution. Conclusions: gas distribution in different sections of roadway is uneven, and gas will be fully homogeneous with air after moving 100 m in front of working face; goaf gas pouring out through the upper corner has a greater impact on distribution of gas concentration. Recommendations for layout of gas monitoring points and sensors in return air of working face were provided, namely gas sensors in return airway should be arranged in central line of the roadway less than 300 mm away from the roof, and a sensor measuring point should be arranged at the place 10 m away from the upper corner.

Solution of Starting Voltage Drop for Mining Truck with Electric Wheel

LIU Qiang, ZHANG Qiang, GUO Hai-qua

2012, 38(11): 21-23.

<Abstract>(46) <PDF>(6)

Abstract:
For problem that control system of mining truck with electric wheel cannot restart after the engine started caused by voltage drop of battery pack, the paper analyzed voltage changes of battery pack in the process of engine starting, and proposed two solutions: increase batteries for separate power supply of the control system, and modify the control circuit. It analyzed advantages and disadvantages of the two solutions and figured the second option is better. The results of plant commissioning and industrial experiments show that the second option is superior. Presently the mining truck with electric wheel adopting the second solution has been successfully operating for 4 000 h, which ensures success rate of start-up of the engine control system is 100%, and starting process is safe and reliable.

Nonlinear Compensation and Control Method of Chaotic Ferroresonance System Based on D-FN

MA Cao-yuan, LIU Jian-feng, GAO Shan, LIU Hao

2012, 38(11): 23-26.

<Abstract>(47) <PDF>(5)

Abstract:
For chaotic phenomenon in chaotic ferroresonance system of power grid, the paper proposed a nonlinear compensation and control method of chaotic ferroresonance system based on dynamic fuzzy neural network. The method uses dynamic fuzzy neural network to approximate nonlinear part of the system, so as to eliminate the chaotic phenomenon of over-voltage and stabilize the system to target location, which achieves nonlinear compensation and control of the system. Matlab simulation results show that using the method can get correct result and fast response.

Research of New Method of Harmonic Elimination of Power Supply System of Mine Industry

LIAO Qing-hua, YANG Liu-lin, LI Can

2012, 38(11): 27-30.

<Abstract>(48) <PDF>(5)

Abstract:
For problems of poor filtering effect and easily leading to resonance overvoltage and harmonic amplification of existing passive filter, the paper proposed a new method of harmonic elimination based on fundamental resonance principle. The method seriesly connects a fundamental resonant circuit composed by inductance and capacitance in three-phase line between electricity grid and passive filter, so as to force harmonic currents to flow into passive filter and significantly enhance efficiency of the filter. The experimental result shows that the current distortion rate drops from 10.6% to 0.942% after adding fundamental resonant circuit, which indicates the new method has better filter effect.

Fault Diagnosis of Power Network Based on Artificial Bee Colony Algorithm

WEI Xiao-guang, CHEN Kui

2012, 38(11): 30-36.

<Abstract>(81) <PDF>(4)

Abstract:
In order to solve 0-1 programming problem in fault diagnosis of power network, the paper proposed optimization methods of artificial bee colony algorithm from aspects of algebra and geometry. The simulation results show that the artificial bee colony algorithm is feasible and reasonable, and the overall performance is significantly superior to traditional genetic algorithms; artificial bee colony algorithm based on geometric has better stability and search capabilities than the algorithm based on algebraic, and is more suitable for occasions with high stability and accuracy requirements.

Design of Pulse Width Modulation of Intelligent Control System of Vibration Stress Relief

WANG An-ming

2012, 38(11): 36-39.

<Abstract>(50) <PDF>(4)

Abstract:
The paper analyzed problems existed in realizing pulse width modulation of intelligent control system of vibration stress relief which includes short timing time of the single-chip microcomputer, method of initial value writing of the timer and low frequency accuracy, and gave corresponding solutions. It proposed basic idea of using single-chip microcomputer to realize pulse width modulation: timers of the single-chip microcomputer are timed respectively at high level and low level to make common I/O interface output pulse with constant frequency or variable frequency and constant width. The Proteus and Keil C joint simulation results show that the design method of pulse width modulation of intelligent control system of vibration stress relief can output pulse signal meeting the requirements.

Research of Prediction of Coal and Gas Outburst Based on Semi-supervised Learning and Support Vector Machine

SUN Yun-xiao, FANG Jian, MA Xiao-ping

2012, 38(11): 40-42.

<Abstract>(62) <PDF>(6)

Abstract:
For the problem that support vector machine requires input vectors are labeled samples which are difficult to obtain in practical application, the paper proposed a prediction method of coal and gas outburst combining semi-supervised learning and support vector machine. It introduced prediction process of support vector machine and selection of input vectors, and improved co-training algorithm of semi-supervised learning: train two different classifiers of SVM and KNN in the same attributes set, and add the samples with the same label in the training set, so as to take full advantage of unlabeled samples to add information continuously, update labeled samples in the training set, and achieve purpose of intensifying training sets. The test result shows that the improved algorithm has higher accuracy than the prediction method using separate support vector machine.

Design of an Improved Protection Scheme of Mine Zone Selective Interlocking

HUANG Cui-bai, TANG Bai-shan

2012, 38(11): 43-46.

<Abstract>(56) <PDF>(4)

Abstract:
For problems that response time of underground integrated protection switches is long and uncertain because the switches are coming from different manufacturers and have different models, the paper proposed an improved protection scheme based on analysis of traditional protection scheme of zone selective interlocking: connect switch lockout signal interface of intelligent control module in tripping signal circuit of integrated protection switches in series, use 1:1 Hall-type current sensor to obtain current signal from secondary side of current transformer of the original protective device, and take the signal as acquisition signal of the intelligent control module. The scheme detects fault current through current sensor directly, which avoids protection from impact of integrated protection switches. The testing result shows that the intelligent control module in the improved scheme has response time of 800 μs, response speed is significantly improved compared with the traditional scheme.

Research of Fault Diagnosis Method of Asynchronous Motor

SHI Peng-fei

2012, 38(11): 46-49.

<Abstract>(37) <PDF>(5)

Abstract:
The paper introduced principles of fault diagnosis method based on Park vector transformation, spectrum analysis of stator current based on Fourier transformation and the method based on wavelet transformation, and analyzed and discussed application effects of the three methods in fault diagnosis of three-phase cage type asynchronous motor.

Research of Walking on Soft Soil Road of Compound Obstacle Crossing Robot with Master-slave Track

XU Fei, YANG Hai-zhong

2012, 38(11): 50-52.

<Abstract>(57) <PDF>(9)

Abstract:
The paper analyzed principle of mechanical system of crawler travel system, and used multi-body dynamics software of RecurDyn to do simulation and analysis of walking state on flat road with soft soil of virtual prototype of compound obstacle crossing robot with master-slave track. The simulation results show that the gravity center of the prototype does not coincide with the geometric center, which leads down track of guide wheel to sink lower than other tracks, while the uneven pressure distribution may lead to locally grounding of track and reducing track life. So the rational allocation of gravity center of prototype should be paid attention to during design.

Research of Zone Interlocking Protection Scheme of Underground Power Grid and Its Real-time Performance

DONG Yu-jie, XU Dan, GUO Yi-du, YU Ying-ying

2012, 38(11): 53-56.

<Abstract>(48) <PDF>(4)

Abstract:
For the problem that communication network for power supply system of underground cannot meet real-time performance and reliability requirements of data transmission, and hardly achieves fast action and selectivity of protection simultaneously, the paper proposed a zone interlocking protection scheme based on switched Ethernet, and used OPNET network simulation software to study real-time performance of the switched Ethernet. The scheme adopts switched Ethernet of tree structure, and composes regional interlock system by adding smart interlock devices with Ethernet communication interface to integrated protection devices. The simulation results show that the maximum delay of overall network is less than 0.65 ms, the maximum end-to-end delay is less than 1 ms, and overall data transceiver flow is relatively smooth in the extreme case of 64 network nodes sending or receiving data at the same time, which illustrate that switched Ethernet has high stability and reliability to meet real-time requirements of interlock protection system in the region and prevent override trip accident.

Design of Baudrate Adaptive RS485 Isolating Repeater

YANG Sheng-yua

2012, 38(11): 56-60.

<Abstract>(81) <PDF>(7)

Abstract:
For the problem that traditional RS485 isolating repeater needs waiting time for state conversion of sending and receiving, the paper proposed a design scheme of baudrate adaptive RS485 isolating repeater with programmable counter array of single-chip microcomputer as control core. It analyzed design principles and disadvantages of three kinds of traditional RS485 isolating repeaters, and introduced principle, calculation of baudrate and actual byte sending time of the baudrate adaptive RS485 isolating repeater. The practical application shows that data transmission of the repeater is stable and reliable under the condition of communication baudrate less than 100 kbit/s and can meet requirements of remote communication of mine-used products.

Design of a Mine-used Air Speed Sensor Based on Pitot Tube

JIANG Ze, HAO Ye-jun, LIU Ya

2012, 38(11): 61-63.

<Abstract>(80) <PDF>(6)

Abstract:
For the problem that traditional air speed sensor always cannot properly reflect value of ambient air speed because underground environment often causes performance degradation of ultrasonic probe, the paper proposed a design scheme of mine-used air speed sensor based on Pitot tube, and introduced principle and designs of hardware and software of the sensor in details. The sensor uses S-type Pitot tube to measure air pressure, uses differential pressure chip to calculate value of differential pressure signal, and calculates air speed according to corresponding relationship among electrical signal, differential pressure signal and air speed. The experimental results show that measurement error of the sensor is less than ±0.2 m/s in air speed range of 0.4～15 m/s, and the sensor has good characteristics of temperature stability, storage, moisture proof and dustproof.

Research of Harmonic Elimination and Reactive Power Compensation of Mine Electricity Grid and Its Application

GUO Jin-long, LV Jing-jiang, WANG Yi-lei

2012, 38(11): 64-66.

<Abstract>(40) <PDF>(4)

Abstract:
For problems of voltage and current distortion and capacity waste of grid caused by harmonic pollution, power quality testing and analysis were given, and a scheme of using SVG for harmonic elimination and reactive power compensation were proposed combined with the actual situation of Yaoqiao Coal Mine of Shanghai Datun Energy Co., Ltd.. Results of harmonic elimination and reactive power compensation: power factor raised from 0.8～0.85 to 0.98～1; total harmonic distortion of voltage was less than 4.0%, odd harmonic distortion was less than 3.0%, even harmonic voltage distortion was less than 1.5%; harmonic current was greatly reduced and power quality was greatly improved.

Application of Intelligent Current Protection of Zero Time Limit in Radial Distribution Network

DING Jing-bo

2012, 38(11): 67-69.

<Abstract>(52) <PDF>(3)

Abstract:
For problems that traditional current protection in multistage radial distribution network cannot meet selectivity and speed requirements at the same time and has protection dead zone, principle and application examples of an intelligent current protection scheme of zero time limit were introduced. Optical fiber is used to achieve information exchange between current protections at the lower and upper levels, which solves the problem of protection coordination. Delay time of quick break protection of protection devices at all levels are set to 0 s so that quick break protection of incoming line can be the main protection of bus fault at the same time, which solves the problem of protection dead zone. The application result shows that the scheme can block underground override trip successfully.

Design of Practical Training Platform of Mine AC Hoist Control System

YANG Liu, YAN You-yun, HAN Chao-chao, CAO Hong, SU Hao-fei

2012, 38(11): 69-72.

<Abstract>(92) <PDF>(3)

Abstract:
A practical training platform of mine AC hoist control system based on PLC was designed, and overall design and design schemes of software and hardware were introduced. The control system takes S7-1200 PLC as control core, three-phase asynchronous motor as power source, and DC motor as load, and achieves simulation of operating conditions of AC Hoist with specific load by using inverter and DC speed regulator separately for speed regulation of three-phase asynchronous motor and DC motor. Through the training platform, the trainees can get a general understanding of running principles and operation methods of modern mine AC hoist system, so as to achieve training objectives.

Design of Detecting Sensor of Roof Separation Based on Industrial Ethernet

LI Xue-zhe, HUANG Cheng-yu

2012, 38(11): 73-76.

<Abstract>(58) <PDF>(5)

Abstract:
In view of problems of low measuring precision and no way to upload measuring result existed in troditional detection methods of roof separation, a detecting sensor of roof separation based on industrial Ethernet was designed. The sensor uses two draw-wire displacement sensors to detect deep displacement and shallow displacement of roof separation and uses displacement detection circuit to transform current signal output by the draw-wire displacement sensors to voltage signal for sampling by single-chip microcomputer. The single-chip microcomputer analyzes displacements of deep part and shallow part according to sampled voltage value to get roof separation value which is uploaded automatically through industrial Ethernet to surface monitoring computer. The test result shows that the sensor can realize accurate measurement of displacement of roof separation with ±2.5% measuring error and can upload measuring result easily.

OLAP Analyzing System of Coal Sale Data Based on Hadoop Platform

NIE Rui, LU Jian-jun, WEI Chen

2012, 38(11): 77-80.

<Abstract>(45) <PDF>(3)

Abstract:
For the problem that coal sale data has large volume but little information content, the paper proposed a design scheme of OLAP analyzing system of coal sale data based on Hadoop platform, introduced design ideas and structure of the system, and described specific process of implementation of deep and fast mining and intuitive display of data taking statistics of sales data as an example. The system uses Hadoop cloud platform for ETL data processing, creates Hive distributed data warehouse, and uses HQL language of Hive for OLAP statistical analysis, which achieves deep data mining, statistics and analysis of sales information from multi-level and multi-angle quickly and accurately, meanwhile reflects the result of data analysis intuitively form multi-angle.

Research of Temperature Measuring Method of Automatic Protection Device of Explosion-proof Diesel Locomotive

LI Fei

2012, 38(11): 81-83.

<Abstract>(68) <PDF>(3)

Abstract:
The paper analyzed common temperature monitoring methods, pointed out that the temperature measuring method of platinum thermistor is suitable for temperature monitoring of automatic protection device of diesel locomotive, and introduced specific implementation of the method. The method calculates value of platinum thermistor according to ADC sampling value, and then calculates temperature according to relationship of platinum thermistor and temperature of measuring points. The industrial field application result shows that the method responses fast with stable feature in temperature measuring range and has no temperature drift during long running process.

Fully Distributed Gas Monitoring and Control System Based on LonWorks Bus

YANG Shuai, ZHOU Kui, XUE Lan

2012, 38(11): 84-87.

<Abstract>(72) <PDF>(3)

Abstract:
For problems of complex wiring and high transmission error rate of traditional master-slave gas monitoring and control system, the paper proposed to build fully distributed gas monitoring and control system using LonWorks technology, and introduced structure and designs of hardware and software of fully distributed gas monitoring and control system based on LonWorks bus. The system is consisted of three layers of monitoring sub-stations, network controllers and monitoring workstations. Network controllers are used for remote communication between monitoring sub-stations and workstations, and monitoring sub-stations are used for on-site gas monitoring. The test result shows that the system has good performance, whose control and execution time is no more than 1 s and transmission error rate is less than 10-6 under certain conditions.

Application of Energy Recovery System for Pressure Fan in Juji Coal Preparation Plant

ZHANG Wen-bin, LIU Xian-pu

2012, 38(11): 87-89.

<Abstract>(57) <PDF>(4)

Abstract:
For problems that exhaust heat of pressure fan cannot be effectively recycled and result in great waste, combined with current situation of thermal systems of Juji Coal Preparation Plant, the paper proposed a scheme of using energy recovery system for heat recovery of pressure fan and supplying heat to bathhouse of the coal preparation plant replacing boiler room. The result of benefit analysis shows that the system can recover heat of 8 820 MJ per day, and save electricity charge of 493 900 yuan per year, which not only has effect of energy saving and emission reduction, but also saves cost for the enterprise significantly.

Improvement Design of Mid-set High Voltage Capacitor Cabinet

ZHANG Hong-guang, WANG Ling, QIAO Jun-li

2012, 38(11): 90-93.

<Abstract>(42) <PDF>(3)

Abstract:
The paper analyzed problems of original design scheme of high voltage capacitor cabinet of Baimahe air shaft substation in Nantun Coal Mine, and gave its improvement design: selecting vacuum circuit breaker for capacitive load; adding discharge coil and connecting the coil with a capacitor in parallel directly to form a complete discharge circuit; adding grounding switch which has both mechanical latch and electrical interlock for easy operation and high security. The practical application shows that the improved high-voltage capacitor cabinet has more functions and high security and reliability.

Design of Integrated Monitoring and Control System for Inclined Drift Transportation of Coal Mine

ZHANG Yong-fu, SHI Er-ting, TIAN Jian-jun, YANG Kun

2012, 38(11): 93-95.

<Abstract>(60) <PDF>(4)

Abstract:
For problems that most inclined drift transportation devices of mine had poor reliability and backward control mode, the paper proposed a design scheme of integrated monitoring and control system for inclined drift transportation of coal mine taking PLC as control core, described system architecture, main field equipments and system functions in details. The system achieves speed and location measuring of winch and monitoring of moving vehicles and staff, realizes visualization of inclined drift by video surveillance devices, and implements contact of ground staff and inclined drift staff, as well as maintainer of each section and winch drivers by communication devices. The practical application shows that the system has flexible and convenience operation and strong reliability.

Research of Intelligent Monitoring, Analysis and Management System of Power Quality

ZHANG Peng-fei

2012, 38(11): 96-98.

<Abstract>(39) <PDF>(7)

Abstract:
The paper introduced an intelligent monitoring, analysis and management system of power quality, and focused on overall structure, software architecture and function modules of the system. The system can online monitor electricity consumption situation and power quality of substation real-timely, classify and process collected information automatically, and achieve functions of online and association analysis of power quality and emergency alarm, which provides a reference for power grid plan, power quality trend forecasting, event prediction, pollution control and resolution of power quality disputes.

Automatic Recognition Method of Handwritten Number in Mine Geological Record

MA Fei, CHENG Rong-hua, LV Hai-lia

2012, 38(11): 99-101.

<Abstract>(64) <PDF>(3)

Abstract:
For the problem that mine geological record uses manual recognition for handwritten numbers with low efficiency, the paper proposed an automatic recognition method of handwritten numbers, and introduced steps of color filtering and positioning of number area, number divide, sample training and number recognition in details. The method uses computer image processing technology to locate and identify numbers in specific region automatically, which improves work efficiency.

Improvement Design of Gangue Blocking Device of Shearer with Large Mining Height

LI He, ZHANG Xiao, ZHANG Li-ming, YAN Peng-fei

2012, 38(11): 101-103.

<Abstract>(41) <PDF>(3)

Abstract:
The structure, principle, technical characteristics and existed problems of traditional gangue blocking device of shearer with large mining height were analyzed, an improvement design was proposed and simulation analysis was given. By means of increasing cylinder number, strengthening and thickening top guard, changing rigid connection to flexible connection and adding flow dividing and combining valves, dynamic adjustment and bracing of the guard are achieved, and reliability of gangue blocking device and mining efficiency of shearer are both improved. The simulation result shows that the force of the improved gangue blocking device is more even, and the guard can withstand greater force.

An Anti-Override Trip System Based on Principle of Zone Protectio

ZHAO Fu-yu

2012, 38(11): 104-106.

<Abstract>(37) <PDF>(3)

Abstract:
The paper introduced an anti-override trip system based on principle of zone protection, described basic idea and working process of zone protection technology and generating and control logic of blocking signal in details, and analyzed an example of power supply system of a coal mine. The analysis result shows that anti-override trip system based on principle of zone protection makes the relay protection of underground substation no longer rely on coordinate of fault current value and operating time, which can cut off fault quickly and accurately to achieve protection selectivity and improve protection level of underground substation.

Design of Driver Control System of Monorail Turnout Based on PLC

XIAO Lin-jing, GUO Shuai, GAO Feng, SUN Chuan-yu

2012, 38(11): 106-108.

<Abstract>(59) <PDF>(4)

Abstract:
For problems that manual control method of monorail turnout may lead to frequent switch of monorail and low transport coherence, a driver control system of monorail turnout based on PLC was designed. The system takes PLC as control core, realizes functions of rernote driver control and status indication of turnout and fault alarm, which insures security and continuity of monorail transportation and improves automation degree and efficiency of auxiliary transportation system of coal mine.

2012 Vol. 38, No. 11

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