2018 Vol. 44, No. 7

Display Method:
Design of hydraulic pressure driven rodless drainage control system
LIU Lei, JIANG Zaibing, SHU Jiansheng
2018, 44(7): 1-5. doi: 10.13272/j.issn.1671-251x.2018010047
Abstract:
For low control precision and work efficiency of existing rodless drainage equipments of coalbed methane and large labor intensity in drainage field, a hydraulic pressure driven rodless pump was designed as well as a hydraulic pressure driven rodless drainage control system based on PLC. The system uses underground pressure transmitter to measure bottom-hole flow pressure and PLC to control inverter to adjust motor speed through comparing measured flow pressure with the set one, so as to adjust bottom-hole flow pressure. The hydraulic pressure driven rodless pump does reciprocating motion, which is driven by power fluid in power fluid pipe of three-channel oil pipe, so as to realize automatic up-down switching between valves without labor operation. The experimental result shows that the system can adjust bottom-hole flow pressure to approach the set one quickly and correctly with small overshoot.
Design of pedestrian monitoring and protection system of continuous shearer
HUANG Limin, LIU Xudong, CAO Lianmin, YAN Mingwei
2018, 44(7): 6-11. doi: 10.13272/j.issn.1671-251x.2018010005
Abstract:
In view of potential safety hazards of accidentally injuring pedestrians during operation process of conveyor at the back of continuous shearer, a pedestrian monitoring and protection system of continuous shearer based on infrared thermal imaging was designed. Firstly, long-wave infrared probe was used to monitor sensitive areas of the conveyor at the back of continuous shearer and real-timely collect infrared image information in the sensitive areas. Then, microprocessor was used to process the infrared image information, and pedestrians were detected; when pedestrians were detected entering the sensitive area, the pedestrian information would be rapidly judged by microprocessor within 1 s, meanwhile an early warning protection strategy would be triggered; when the pedestrians exited the sensitive area, the early warning protection mechanism would stop automatically; when the pedestrians passed over the sensitive area, at that time, an emergency stop control strategy would be triggered by microprocessor, so as to make the conveyor at the back of continuous shearer stop urgently to protect safety of crossing pedestrians. The site test results show that the system is stable and reliable with high recognition accuracy, and can effectively monitor pedestrians within the range of 1 to 2 meters on the front left area of the conveyor at the back of the continuous shearer, which effectively guaranteed life safety of pedestrians nearby the continuous shearer.
Conceptual design system of three machines matching of fully mechanized coal mining equipment
DUAN Qi, DING Hua, WANG Yiliang, DENG Jintao
2018, 44(7): 11-16. doi: 10.13272/j.issn.1671-251x.2018010023
Abstract:
In view of problems that most of existing intelligent design methods of fully mechanized coal mining equipment are not considered complex coupling relationship among design parameters of three machines matching, which leading to poor applicability of the system and isolated design knowledge, a conceptual design method and matching principle of three machines of fully mechanized coal mining equipment based on knowledge reasoning were studied, the hybrid reasoning mechanism including case reasoning, rule reasoning and model reasoning was applied to the conceptual design of three machines matching of fully mechanized coal mining equipment, reasoning model of conceptual design of three machines matching of fully mechanized coal mining equipment based on the knowledge reasoning was established, conceptual design system of three machines matching of fully mechanized coal mining equipment based on knowledge reasoning was developed. The system uses knowledge reasoning method to do case reasoning of input initial parameters for user, and search similar case in the case database, so as to obtain satisfactory design scheme, if there is no similar case in the case database, parameter design of three machines matching was completed by model reasoning, so as to get parameter design scheme. The application example shows that the system has accurate design result and fast reasoning speed, which realizes intelligent design of fully mechanized coal mining equipment and shorten design cycle of products.
Design of dispatching management system of mine-used locomotives
WU Wei, TANG Lijun, TIAN Guozheng
2018, 44(7): 17-21. doi: 10.13272/j.issn.1671-251x.2018010020
Abstract:
In view of problems of low efficiency of material transportation, safety hazards of potential safety of personnel and locomotive coexistence in incline roadway, and not fused linkage control system of winch existed in dispatching management system of vehicle, a novel dispatching management system of mine-used locomotives was designed. The dispatching management system includes three subsystems, namely accurate positioning system of locomotives, material management system of locomotives and linkage control system of winch. The accurate positioning system of locomotives uses wireless signal flight time positioning method to real-timely locate and track underground vehicle, and positioning accuracy is less than 1 m. The material management system of locomotives uses dynamic target recognizers and vehicle identification cards to manage materials of each locomotive, and can reduce material backlog. The linkage control system of winch uses dynamic target recognizer to monitor personnel going into the incline roadway, and can prevent from the personnel entering the incline roadway by monitoring operating state of the winch with mine-used breaker. With sharing data of each subsystem, management platform of the dispatching management system can realize general management for the locomotives. The practical application of the system shows that the system can make reasonable dispatching for track, supply situation and traffic safety of underground locomotives.
Transient analysis of surge immunity test for intrinsically safe sensor
ZHANG Ziliang
2018, 44(7): 22-26. doi: 10.13272/j.issn.1671-251x.17323
Abstract:
For problem that it was difficult to achieve evaluation grade A due to a long time reverse gap in DC power port voltage of intrinsically safe sensor in positive surge immunity test, taking a typical mine-used intrinsically safe methane sensor as research object, simulation models of combination wave generator, coupling-decoupling network and equivalent circuit of the sensor were established in ADS simulation software as well as a simulation circuit of surge immunity test at DC power supply port of the sensor. Transient process of the test was analyzed according to transient simulation waveform. The research results show that the reverse gap in DC power port voltage of the sensor is the secondary effect caused by surge protection component, and simulation waveforms are the same as the actual ones, which verify rationality of the transient analysis method.
Research on pulse power supply of MEMS low power consumption catalytic methane sensor
SHEN Guojie
2018, 44(7): 27-31. doi: 10.13272/j.issn.1671-251x.2018020033
Abstract:
In view of problem of high power consumption of traditional catalytic methane sensor, a pulsed power supply operation mode was proposed based on analysis of performance of MEMS low power consumption catalytic methane components. Specific duty ratio of pulse power supply was determined through output stability test and sensitivity test, and linearity, zero temperature characteristics, sensitivity characteristics, zero drift and sensitivity drift of the components under constant voltage supply and pulse power supply were tested. The results show that the pulse power supply operation mode can not only greatly reduce power consumption of MEMS catalytic methane sensor, but also has superior performance in zero drift and sensitivity.
Analysis of critical failure depth of surrounding rock of roadway under blasting disturbance
WANG Xiana
2018, 44(7): 31-35. doi: 10.13272/j.issn.1671-251x.17310
Abstract:
Mathematical expression of critical failure depth of surrounding rock of roadway under blasting disturbance was obtained through elasticity analysis. On the basis, influence rule of roadway excavation radius, blasting vibration speed and cohesion force of surrounding rock on stability of roadway for drilling and blasting excavation were discussed by orthogonal test. Critical blasting vibration velocity which will not destroy surrounding rocks was derived. The analysis results show that as excavation radius of roadway increases by 1 m, the critical failure depth increases by 0.365 m; the critical failure depth increases logarithmically with increase of blasting vibration velocity; the depth of critical failure decreases exponentially as cohesion of surrounding rocks increases; cohesion and blasting vibration velocity are the most significant factors affecting the critical failure depth.
Research on parametric modeling of structures of scraper conveyor
ZHANG Xing, YANG Shanguo, LI Wei
2018, 44(7): 36-40. doi: 10.13272/j.issn.1671-251x.2018020027
Abstract:
In view of problems of high repetition rate and low efficiency of structure design of scraper conveyor, parametric modeling of key components and complex assemblies of scraper conveyor were realized based on Pro/E 5.0 three-dimensional modeling software. Parametric modeling of key components of scraper conveyor mainly includes three steps: 3D model creation, design parameter determination and relationship setting. The parametric modeling process of key components was introduced by taking parametric modeling of drive sprocket as an example. Parametric modeling of complex assemblies of scraper conveyor was implemented based on Pro/Toolkit secondary development technology and Visual Studio 2008. Parametric modeling and virtual assembly process of complex assembly was introduced by taking parametric modeling of middle slot of scraper conveyor as an example. Rapid establishment, modification and precise sculpting of the key components and assemblies of scraper conveyor were achieved by modifying important geometric parameters, which provides basis for structural optimization of scraper conveyor.
Research on performances of speed regulating mechanism of mine-used permanent magnet speed regulator
WANG Lei, JIA Zhenyuan, ZHU Mingliang, ZHANG Li
2018, 44(7): 40-44. doi: 10.13272/j.issn.1671-251x.2018020003
Abstract:
Structure and principles of mine-used permanent magnet speed regulator were introduced. A sinusoidal-based speed regulating groove was designed and contact stress of the groove was analyzed by finite element method. Axial force and air gap value in the permanent magnetic speed regulator were fitted by function curve, according to characteristic function curve of the groove, torque values under different air gaps were obtained. Actual output torque of actuator was obtained through test。By comparing theoretical calculation value of torque with the test results, it is found that both have the same change trend and high coincidence degree, peak torque error was 5.5%.Through numerical calculation method of function curve fitting, the value of speed regulation torque under different air gaps is quantified, which can provide technical support for research of speed regulating mechanism of permanent magnet speed regulator.
Research on antenna model of underground magnetic induction communication and its signal transmission characteristics
SHI Wenjuan, WANG Liang, SUN Yanjing, XU Hua, XU Sheng, WU Tianqi
2018, 44(7): 45-53. doi: 10.13272/j.issn.1671-251x.17316
Abstract:
In view of problem that magnetic signal propagation had significant directionality, but effect of antenna position and angle on transmission performance in magnetic communication had not been fully considered by current researches, magnetic signal transmission characteristics of three kinds of antenna models of underground magnetic induction communication were researched including double-coil array and four-coil array in 2D antenna array and 3D coil model. Firstly, expressions of corresponding magnetic induction intensity and mutual inductance between sending coil and receiving coil were given according to mathematical models of the three antennas. Secondly, magnetic induction intensity was simulated and analyzed. Position and angle of receiving antenna were optimized according to magnetic field distribution. Finally, transmission performances of the three antenna models were compared, and influences of offset of each sending coil and vertical distance between sending coil plane and receiving coil plane on magnetic induction intensity were given. The research results are as follows: ① Magnetic induction intensity of 2D antenna array model and 3D coil model has symmetry and directionality. ② Transmission direction of 2D antenna array model changes from multiple directions to one direction as the vertical distance increases. ③ When parameters of sending coils are as the same, transmission distance of 2D antenna array model is greater than that of point-to-point communication system and 3D coil model. The more the number of sending coils, the farther transmission distance of 2D antenna array model is. But magnetic induction intensity rapidly decreases as the vertical distance increases. ④ 3D coil model has the same distribution of magnetic induction intensity in three coordinate axes. Magnetic field of 3D coil model is the most widely distributed, but norm of magnetic induction intensity is less than the one of 2D antenna array model.
Research on continuous restrictive pulse train controlled switching converter
LI Shanshan, WEI Yujin, ZHU Haiming, LIU Jiangwen
2018, 44(7): 54-60. doi: 10.13272/j.issn.1671-251x.2018030019
Abstract:
For larger low-frequency oscillation of pulse train(PT) controlled switching converter under inductor current continuous conduction mode (CCM) which could degrade operation performance of switching converter, a continuous restrictive pulse train (CR-PT) control method was proposed. Operation principle of CR-PT control method and its mechanism of suppressing low frequency oscillation of switching converter were introduced in detail by taking CR-PT controlled Buck converter as an example. Switching mapping model of the CR-PT controlled Buck converter under CCM was established. Output voltage and inductor current of Buck converter were compared under PT control and CR-PT control separately through Matlab simulation and prototype experiment. Research results show that compared with PT control method, CR-PT control method can effectively suppress low-frequency oscillation of switching converter under inductor current CCM through restricting the number of continuous pulses.
Experimental study on composite gas indexes optimization for coal spontaneous combustion predictio
WU Fusheng
2018, 44(7): 61-65. doi: 10.13272/j.issn.1671-251x.17341
Abstract:
Changing rule of composite gas indexes under different dry air flow and oxygen concentration was analyzed through coal temperature-programmed experiment. The experimental results show that φ(O2)/(φ(CO)+φ(CO2)) should be selected as gas indexes for coal spontaneous combustion prediction in the case of uncertain dry air flow. φ(O2)/(φ(CO)+φ(CO2)) can be used as gas indexes for coal spontaneous combustion prediction when coal temperature is below 100 °C. φ(C2H4)/φ(CH4) and φ(CO)/φ(CO2) can be used as gas indexes for coal spontaneous combustion prediction when coal temperature exceeds 100 °C. φ(C2H4)/φ(CO) can also be used as gas indexes for coal spontaneous combustion when coal temperature exceeds 160 °C and oxygen volume fraction is approximately 5%.
Development of series fault arc simulation experimental device
GUO Fengyi, RUAN Junyi, DENG Yong, WANG Zhiyong, WANG Shaolei, LI Chuan, WANG Peilong
2018, 44(7): 66-70. doi: 10.13272/j.issn.1671-251x.2017120024
Abstract:
In view of problem that current fault arc generator device could not simulate temperature and humidity of environment and contact separation state, a series fault arc simulation experimental device was developed. The device can simulate series fault arc under different working conditions by controlling temperature and humidity of environment, contact separation state such as movement distance and frequency and amplitude of vibration, and real-timely display and store temperature and humidity of environment, arc voltage and arc current. The experimental results verify effectiveness of the device.
Numerical simulation of dust concentration distribution in transfer site of belt conveyor
QIN Zhu
2018, 44(7): 70-74. doi: 10.13272/j.issn.1671-251x.2018010064
Abstract:
For problem that current research on dust control at transfer site of belt conveyor was mainly limited to specific measures such as dust removal or dust reduction, which results in unsatisfied dust control effect, influences of inducing air flow, shear air flow and traction air flow which formed during coal transportation at transfer site on dust generation was analyzed starting from dust inducement at transfer site. Take force of coal material at straight-line transfer site as an example, structure parameters of transfer site which influence dust concentration distribution were obtained. Numerical simulation of dust concentration distribution under different inclination, section area and section shape of transfer site was conducted by use of Fluent software. The results show that the larger the inclination is, the larger the dust distribution range and the higher the dust concentration at transfer site outlet is. The larger the section area is, the lower the dust concentration at transfer site outlet is. When section area is the same but section shape is different, dust concentration at transfer site with circular section shape is the lowest.
Electric bucket teeth missing detection method based on machine visio
DUAN Yuxiu, DU Wenhua, ZENG Zhiqiang, WANG Rijun, DUAN Nengquan, LI Xiaona
2018, 44(7): 75-80. doi: 10.13272/j.issn.1671-251x.2018030006
Abstract:
In view of problems of lower real-time performance and higher false rate of existing detection methods of electric bucket teeth, an electric bucket teeth missing detection method based on machine vision was put forward. The method uses infrared thermal imager to collect bucket image, adopts template matching principle to accurately locate target area of bucket teeth under complicated background, and uses frame differential method to realize motion detection of bucket teeth. On the basis of location of the target area, the bucket teeth are segmented and extracted combined with location relation of the bucket teeth line area and the teeth line structure characteristics, so as to detect missing bucket teeth according to self-adaptive threshold. The experimental results show that the method can effectively realize real-time on-line, rapid and accurate detection of the missing teeth of the electric bucket, detection accuracy is more than 90%, which provides an effective solution for electric bucket teeth missing detection.
An underground video image enhancement algorithm
FU Yan, LI Yao, YAN Binbi
2018, 44(7): 80-83. doi: 10.13272/j.issn.1671-251x.2017120014
Abstract:
For problems of uneven brightness, blurry detail texture and much noise existed in underground video images, and image distortion, unclear image level and low processing efficiency of common image enhancement algorithm used to process underground video image, an underground video image enhancement algorithm based on contrast limited function and feedback function was proposed. Firstly, image is preprocessed with grayscale and denoising by weighted average method and median filtering. Then contrast is enhanced by use of contrast limited function. Finally, gray level is adjusted by feedback function so as to enhance image level. The experimental results show that the algorithm can effectively improve underground video image distortion with clear level and fast processing speed.
Research on laser measuring device of surface displacements of mine roadway
YE Meitu, LIANG Yiwei, WANG Kun
2018, 44(7): 84-87. doi: 10.13272/j.issn.1671-251x.2017120086
Abstract:
In view of problems of inconvenient measurement, time consuming, high labor intensity and uncontrollable errors of existing cross-measuring methods of surface displacements of mine roadway, a laser measuring device of surface displacements of mine roadway was designed. Based on the principle of laser ranging, the device uses laser range finder to complete measurement of cross centering and deformation, and can measure surface displacements of the roof, floor, left and right sidewalls of each testing station in roadway respectively by single laser range finder. The underground test results show that the device realizes cordless measurement with high measuring efficiency, accurate results, and accuracy up to 1 mm, which meets requirements of mine.
Reliability approximation calculation method of roof beam of hydraulic support
WANG Lei, LU Jingui, CHEN Yong
2018, 44(7): 88-91. doi: 10.13272/j.issn.1671-251x.2018020046
Abstract:
In view of problem that detailed reliability calculation method of roof beam of hydraulic support has large amount of calculation, a reliabillty approximation calculation method of roof beam of hydraulic support based on neural network model was proposed. Neural network model for reliability approximation calculation of roof beam was established. The back propagation algorithm is used as weight learning algorithm, and square type function is used as error function. Taking roof beam of ZY18000/25/45D hydraulic support as an example to calculate the reliability, the results show that relative error of roof beam reliability calculation is within 6.3%.
Design of real-time and on-line monitoring system for mine dynamic disaster
LI Xianghe
2018, 44(7): 91-95. doi: 10.13272/j.issn.1671-251x.2018040029
Abstract:
In view of shortcomings that current monitoring of deep dynamic disaster in coal mine mainly depends on the on-line collector,which cannot realize data parallel and rapid sampling, a set of real-time and on-line monitoring system for mine dynamic disaster was designed. In the system, acoustic emission sensors, gas sensors and stress sensors are used to real-timely monitor parameters of strain energy, gas concentration and stress of coal and rock during occurrence of mine dynamic disaster; monitoring station is used to real-timely collect and process various sensor signals; PC data management software is used to realize effective analysis and results early warning of characteristic parameters change rule, so as to realize continuous dynamic monitoring of the dynamic disaster. Actual application results prove reliability of the system.
Design of multivariate early warning management system for fully-mechanized coal mining equipment
YANG Rui, CAO Kai, WANG Jiyu
2018, 44(7): 96-99. doi: 10.13272/j.issn.1671-251x.2018040063
Abstract:
In view of problems of low accuracy, low efficiency and poor timeliness in current management mode of fully-mechanized coal mining equipment, a multivariate early warning management system for fully-mechanized coal mining equipment was designed. The system comprehensively analyzes data rules of equipment accident, equipment abnormality and maintenance, equipment repair and replacement and evaluates equipment operation state by collecting multivariate data from equipmen, personnel, production and working face, so as to realize early warning and prediction of equipment accident, planned active maintenance and spare parts procurement guidance. The system effectively reduces failure rate of fully-mechanized coal mining equipment and improves equipment management level of enterprise.
Design of coal seam gas pressure monitoring system based on 6LoWPA
LIU Shaofei, WANG Guofu, ZHANG Faquan, YE Jincai
2018, 44(7): 99-103. doi: 10.13272/j.issn.1671-251x.2018010089
Abstract:
In view of problems of low measurement accuracy, delayed data transmission and inconvenient equipment deployment existed in current coal seam gas pressure monitoring, a coal seam gas pressure monitoring system based on 6LoWPAN was designed. In the system, pressure measurement node selects the optimal path in 6LoWPAN network through multi-hop mode, so as to transmit gas pressure data collected in real time to border router. The border router transmits the data to ground server through industrial Ethernet, and ground equipment can query real-time monitoring data of pressure measurement node in specified area through the server. The test results show that the system can real-timely and accurately monitor coal seam gas pressure with high data communication efficiency and stability and low power consumption.