工矿自动化

Development and innovative practice from coal mine mechanization to automation and intelligence: Commemorating the 50th anniversary of the founding of Journal of Mine Automation

WANG Guofa, DU Yibo, CHEN Xiaojing, WANG Hui, BAO Jianjun, XING Zhen, HE Yaoyi, HAN An, GU Yidong

2023, 49(6): 1-18. doi: 10.13272/j.issn.1671-251x.18132

<Abstract>(1419) <HTML> (57) <PDF>(154)

Abstract:
This paper reviews the general situation of the development and innovation practice of China's coal industry in the past 50 years promoted and witnessed by the Journal of Mine Automation from coal mine mechanization to automation and intelligence. This paper expounds on the innovation process of coal mine automation and intelligence. It focuses on the analysis of the research and development and practice of coal mine information infrastructure, automation and intelligent equipment and systems. The integration and unified hosting of heterogeneous networks is the information foundation for coal mine automation and intelligence. On the basis of the continuous maturity of the heterogeneous network of the backbone network and access network, the wired communication transmission rate has reached over 10 Gibit/s. The wireless communication technologies such as 5G and WiFi6 have been widely applied, providing a reliable communication platform for the intelligent construction of coal mines. Wired communication, wireless communication, IP broadcasting, personnel locaiton monitoring system, and video monitoring system are integrated to build a multi-network integrated communication system, achieving integrated carrier network and unified location service. The development of intelligent automation equipment in coal mines is rapid. It explores adaptive cutting technology based on transparent geology, automatic coal release control technology on the basis of technologies such as memory cutting of coal mining machines and automatic following and moving of hydraulic brackets at coal mining working face. On the basis of achieving profiling cutting, positioning navigation, and remote control, the excavation working face has made breakthroughs in technologies such as drilling anchor integration, multi-machine collaboration, and cutting template planning of roadheader based on geological model, achieving good results. The development of intelligent equipment for coal flow transportation systems is supported by intelligent variable frequency energy-saving transmission. The integrated research and application of coal mine robots are achieved. The mature application of inspection robots is obtained. The breakthroughs in intelligent auxiliary operation robots are achieved. The development of a multi-scene robot cluster scheduling and command system forms a robot cluster. The automation and intelligent construction of coal mines have officially entered the stage of intelligent mine comprehensive control from single system automation, comprehensive mine automation, and the Internet of Things. The realization of intelligent perception, intelligent self-control, high-speed transmission, collaborative control, and intelligent decision-making is an inevitable requirement for the development of intelligence. The paper proposes key directions for the iterative development of coal mine intelligent technology, including the establishment of high-precision transparent geological models, the normal and reliable operation of unmanned operating systems, the construction of intelligent compatibility and collaboration mechanisms for coal mine giant systems, the intelligent collaborative control of the entire process of "excavation, mining, transportation, washing, and sales", and the optimization of a flexible coal production and supply system.

The new generation of information technology empowers the digital and intelligent transformation and upgrading of coal mining equipment

JIN Zhixin, YAN Zhirui, WANG Hongwei, LI Zhenglong, SHI Lingkai

2023, 49(6): 19-31. doi: 10.13272/j.issn.1671-251x.18123

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Abstract:
Currently, the intelligent construction of coal mines is in a transitional exploration period from primary to intermediate and advanced intelligence. The independent innovation capability of existing intelligent equipment still needs to be strengthened. The core technologies are bottleneck problems. The reliability problem under complex underground storage conditions is prominent. It is of great significance to use the new generation of information technology to promote the digital transformation and upgrading of coal mine equipment, and to promote safe, efficient, and green coal mining through digitization and intelligence. This paper reviews the evolution process of intelligent development of coal mining technology and equipment in China. This paper analyzes the production characteristics of each stage of coal mining. It is considered that the coal mine intelligence has completely changed the coal production mode. The production factors are mainly intelligent equipment, intelligent systems, and compound technical talents. They have essentially improved the level of safe and efficient production of coal mines, and helped the coal mines to reduce personnel, increase safety and improve efficiency. Among them, intelligent coal mine equipment is the core element of coal mine intelligence. Considering the demand for the digital and intelligent transformation and development of future coal mine equipment, we have explored the path of integrating the new generation of information technology and coal mine equipment. It uses equipment as an intelligent carrier. It endows the equipment with humanized intelligent capabilities such as intelligent perception and analysis, intelligent judgment and reasoning, intelligent decision-making and control, intelligent diagnosis and learning through the new generation of information technology. The system architecture of the Internet of things, 5G, big data, cloud computing, and artificial intelligence technology enabling intelligent perception, intelligent transmission, intelligent analysis, intelligent computing and intelligent decision-making of coal mine equipment has been constructed. The paper analyzes the theoretical, technical, and talent challenges in the development of digital intelligence in coal mining equipment. The paper proposes suggestions for the development of digital intelligence in coal mining equipment. Consolidating the foundation is the priority. It is necessary to build a top-level design theoretical system for intelligent coal mining equipment, strengthen key core technology research, accelerate the construction of new infrastructure, and consolidate the foundation of intelligent coal mining development. The intelligent technology for coal mining equipment and special application scenarios in coal mines develop in collaboration and coupling. It is suggested to meet the on-site needs of coal mines, form the intelligent technology for coal mine specific scenarios, and explore innovative models of equipment digital intelligence integration. The intelligent technology and green mining technology integrate and develop. It is suggested to create digital, intelligent, and green equipment. It is suggested to develop new models of intelligent, efficient, and low-carbon coal mining, and promote energy conservation and consumption reduction in coal production. It is suggested to establish a sound system for cultivating intelligent talents in coal mines, cultivate interdisciplinary and composite talents, and enhance talent reserves for the construction of intelligent coal mines.

Current situation and prospects of air quality revolution technology in coal mines

YUAN Liang, XUE Sheng, ZHENG Xiaoliang, JIANG Bingyou

2023, 49(6): 32-40. doi: 10.13272/j.issn.1671-251x.18130

<Abstract>(921) <HTML> (53) <PDF>(79)

Abstract:
China's coal mine safe and efficient mining technology is at the leading level in the world. But the occupational diseases induced by dust-based toxic substances, high temperature, high humidity, noise and other occupational hazard have long plagued coal mine employees. At present, occupational disease hazards have exceeded the harm of safety accidents to employees, seriously restricting the industry's future development. The concept of underground air quality revolution is put forward. The status of underground dust control and reduction technology (including coal seam water infusion dust reduction technology, spray dust reduction technology, ventilation dust removal technology, chemical reagent dust suppression technology, underground air quality revolution dust control and reduction system), fuel vehicle emission treatment, underground air quality monitoring and early warning system is comprehensively summarized. In order to further promote the theoretical and technological breakthroughs of the underground air quality revolution, based on the concept of "source-division-grading-strategy" for efficient dust control, we seek to establish a theoretical system for collaborative dust reduction and comprehensive management of multi-source, multiphase, and multi-field dust. The development direction of key technical equipment such as efficient intelligent dust prevention and control technology and equipment in mining areas, and synchronous intelligent monitoring technology and equipment for multiple parameters of mine dust environment has been pointed out. It is pointed out that it is necessary to fully integrate the disciplines of science, engineering, medical management, and establish a multi-agent collaborative system for coal mine dust prevention and control. It will lay a theoretical and technical foundation for the development of the underground air quality revolution from the current initial stage to the intermediate and advanced stages. Step by step, it will achieve the goal of full life cycle occupational health for coal mine employees. Ultimately, it will achieve the goal of reducing or zero incidences of occupational diseases in coal mines, supporting the Healthy China Initiative.

Mine personnel position monitoring technology

SUN Jiping

2023, 49(6): 41-47. doi: 10.13272/j.issn.1671-251x.18138

<Abstract>(742) <HTML> (41) <PDF>(79)

Abstract:
This paper analyzes the technologies of mine ranging and positioning, such as ultrasound, laser, video, inertial navigation, pedometer, and radio. Among them, radio ranging and positioning have the advantages of long positioning distance, small positioning error, no impact from light, little impact from dust, easy identification, and low system cos. They are suitable for positioning mine personnel and precise positioning of mine personnel. The paper analyzes radio ranging and positioning technologies such as UWB, ZigBee, RFID, 5G and WiFi6. Mining UWB has the advantages of long positioning distance, small positioning error, and low cost. It is suitable for precise positioning systems for mine personnel. Mining ZigBee has the advantages of long positioning distance, small positioning error, and low cost. It is suitable for mine personnel positioning systems. Mining RFID has the advantage of having the lowest system cost. It is suitable for coal mine underground personnel management systems. The positioning precision of mine 5G and WiFi6 is lower than UWB, and the system cost is higher than ZigBee. It is unsuitable for mine personnel positioning and precise positioning systems. The received signal strength indication (RSSI), time of arrival (TOA), time differences of arrival (TDOA), two-way ranging (TWR), symmetrical double-sided two way ranging (SDS-TWR), angle of arrival (AOA) and other mine personnel positioning algorithms are analyzed. The RSSI positioning method has a large positioning error, making it difficult to meet the needs of mine personnel positioning and precise positioning. The TOA positioning method requires accurate and synchronized timing between the positioning card and the substation clock. The positioning card and substation have high costs. It is unsuitable for mine personnel positioning and precise positioning. The TDOA positioning method does not require synchronization between the positioning card and the positioning sub-station clock. It has low requirements for the precision of the positioning card clock and low cost of the positioning card. However, it requires accurate timing of the positioning sub-station clock and synchronization between the positioning sub-stations. The positioning substation cost is high. It can be used for mine personnel positioning and precise positioning. The TWR positioning method and SDS-TWR positioning method do not require clock synchronization between the positioning substation and the positioning card, nor do they require clock synchronization between the positioning substations, nor do they require clock synchronization between the positioning cards. This reduces the complexity and cost of the positioning card and the positioning substation. It is suitable for mine personnel positioning and precise positioning. The AOA positioning method system is complex, costly, with large long-distance positioning errors and dead angles. It can only be used for straight-line obstacle-free positioning. The positioning antenna and positioning precision are greatly affected by mechanical vibration. It is not suitable for the independent positioning of mine personnel and precise positioning. However, it can be used in conjunction with other mine positioning methods.

Safety risks monitoring and warning throughout the full lifecycle of mine air stopping

ZHOU Fubao, SHI Guoqing, WANG Yanming, WEI Lianjiang, XIN Haihui

2023, 49(6): 48-56. doi: 10.13272/j.issn.1671-251x.18139

<Abstract>(663) <HTML> (32) <PDF>(31)

Abstract:
Mine air stopping is a key facility separating production systems from abandoned ones. Ensuring full lifecycle risk management is of great significance for ensuring safe production. Based on the current status of comprehensive control technology for mine air stopping, the shortcomings of the existing air stopping management mode are analyzed from two aspects: static attribute information management and dynamic information monitoring. The paper puts forward the concept of intelligent management and control in the full lifecycle of air stopping. It indicates the overall construction path of air stopping risk monitoring and early warning based on big data strategy of the Internet of Things (IoT)+Artificial Intelligence (AI)+Cloud Platform (CP), and integrated with cloud-edge architecture. The IoT platform is applied to access digital monitoring and linkage control equipment for air stopping units, achieving transparency in the full lifecycle control of air stopping. The method focuses on the evolution signs of air stopping information and efficient edge computing. It deploys mobile terminals, edge computers and other field terminals to adapt to online prediction and advance warning of air stopping service status. In the smart cloud, the virtual reality scenario of a distributed mine air stopping and its full lifecycle evolution characteristics are reconstructed iteratively in real time with multi-source fused information and digital twin models at the core. The paper analyzes key theories and and model construction methods, including the physical-digital driving mode of evolution information in air stopping environments, the multi-source heterogeneous data fusion model of air stopping perception information, the edge detection and hierarchical intelligent warning of air stopping anomalies, and the emergency intelligent decision-making and collaborative prevention and control throughout the entire lifecycle of air stopping. The physical and functional architecture of an air stopping full lifecycle safety risk monitoring and warning system based on the IoT is designed. The on-site embedded air stopping multi-parameter integrated monitoring sensors and supporting intelligent hosts are developed. The early sensing and monitoring and warning methods for air stopping risks are proposed to achieve digital empowerment and effectively promote the construction of smart mines.

Research progress and key technologies of intelligent monorail cranes in coal mines

MA Hongwei, DUAN Youyou, XUE Xusheng, SUN Siya, ZHANG Ye, WANG Chuanwei, GUO Yifeng, CUI Wenda

2023, 49(6): 57-67. doi: 10.13272/j.issn.1671-251x.2023050001

<Abstract>(886) <HTML> (261) <PDF>(87)

Abstract:
The advantages and disadvantages of five commonly used mining monorail cranes, namely explosion-proof diesel engine monorail crane, explosion-proof battery monorail crane, pneumatic monorail crane, rope traction monorail crane, and cable dragging monorail crane, are analyzed. It is pointed out that explosion-proof diesel engine monorail crane and explosion-proof battery monorail crane have been widely used for underground equipment and material transportation in coal mines due to their strong transportation capacity. The explosion-proof battery monorail crane has green and clean features. It has gradually become a key research and development equipment for underground auxiliary transportation in coal mines. This paper analyzes the research status of the mining monorail crane system from four aspects of battery drive, positioning, measurement and control, and information transmission. It is pointed out that the current mining monorail crane system has low automation and intelligence levels. To achieve intelligent transportation of the monorail crane, it is necessary to study the key technologies such as lithium battery explosion-proof and battery management of the monorail crane, global and local fusion precise positioning, multi-sensor information fusion intelligent measurement and control, edge computing information transmission, etc. For the explosion-proof and battery management technology of lithium battery, a topology optimization design method of explosion-proof large capacity lithium battery structure based on variable density method, and a balanced management scheme based on improved sparrow search algorithm/genetic algorithm are proposed. For precise positioning technology, a global positioning method based on inertial navigation and odometer fusion, and a local positioning method based on visual+UWB combination are proposed. For intelligent measurement and control technology, an intelligent detection method based on recursive least squares algorithm/second-order approximate extended Kalman filter , the real-time construction method for follow-up electronic fences, and vector control method based on fuzzy rules are proposed. For the information transmission technology, the "local-short range-ground" communication system architecture based on the fusion of 5G network and the distributed data calculation and transmission method based on edge computing are proposed. The proposal of key technical issues and solutions for intelligent monorail cranes in coal mines provides a new approach to accelerate the development of intelligent monorail cranes in coal mines.

Research on underground coal fire source detection

DENG Jun, QU Gaoyang, REN Shuaijing, WANG Weifeng, WANG Caiping, WANG Jinrui

2023, 49(6): 68-77. doi: 10.13272/j.issn.1671-251x.18096

<Abstract>(718) <HTML> (27) <PDF>(36)

Abstract:
This paper introduces the evolution and development process of coal fire and its features. This paper expounds on the detection mechanism and research progress of four layers of space exploration technology divided according to the different spatial positions of detectors. The technologies include underground, surface, aerial, and aerospace detection methods. The paper analyzes the advantages and disadvantages of the above four detection technologies. The existing research problems are pointed out. ① The detection precision is insufficient and it is difficult to accurately delineate the acquisition range. ② The detection technology is outdated, and it is difficult to accurately detect high-temperature points in fire areas. ③ The detection method is single and cannot accurately determine the specific information of underground coal fire combustion. In view of the new features of underground coal fire, such as concealment, coupling and complexity, the development directions of underground coal fire detection technology are proposed. ① The detection instrument data needs to be finely processed, so as to improve the sensitivity of magnetic difference to temperature, the detection precision of the resistivity method, the feature extraction rate and the result precision of the infrared detection method. ② It is suggested to utilize high-tech equipment to serve coal fire detection technology. ③ It is suggested to improve the collaborative utilization of multi-level detection technology. Firstly, large-scale fire detection is carried out using the four th level aerospace remote sensing technology to obtain the basic spatial distribution features of underground coal fire anomalies. Secondly, further exploration is carried out using the third level aerial remote sensing detection technology to obtain the specific spatial distribution of underground coal fires. Finally, a more detailed distribution of high-temperature points in the coal field fire area is obtained by using the surface detection technology and underground detection technology at the second level and the first level to supply and verify. ④ It is suggested to develop 3D visual and dynamic monitoring and early warning of coal field fire areas. 3D inversion and joint inversion imaging are performed by use of data from four different levels of detection technology. Based on the imaging results, visual monitoring and early warning of coal fire development and spread are carried out, so as to achieve active prevention and control of underground coal fine disasters.

Key technology system of fiber optic sensing for intelligent coal mining

FANG Xinqiu, FENG Haotian, LIANG Minfu, CHEN Ningning, WU Gang, SONG Yang

2023, 49(6): 78-87. doi: 10.13272/j.issn.1671-251x.18107

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Abstract:
Intelligent perception is the primary link in intelligent coal mining, providing data support for intelligent decision-making and control. Fiber optic sensing technology provides a solution for intelligent perception in coal mining due to its advantages such as high precision, strong anti-interference capability and environmental tolerance, and flexible and diverse network reuse methods. On the basis of studying the principle of optical fiber sensing technology, the sensing information transmission model between fiber grating and the substrate is constructed. The fiber grating packaging technologies of surface pasted type, grooved landfill type, and surface pasted substrate type are proposed. The spectral reconstruction and temperature compensation are studied to ensure high-precision data perception. The high-precision fiber grating borehole stress sensor, bolt stress sensor, bolt force sensor, roof separation sensor, temperature sensor and other intelligent sensing sensors for mining environment are developed. The fiber grating support tilt sensor, support pressure sensor, curvature sensor and other posture sensing sensors for coal mining working face equipment are also developed as well as fiber grating sensor calibration workbench. They are intelligent sensing equipment based on fiber optic sensing technology for the construction of intelligent coal mining faces. Multiple fiber grating sensors are integrated to construct an intelligent multi-parameter perception system based on fiber grating for coal mining environment and working face equipment posture. It solves problems such as the large capacity of multiple sources and heterogeneity of sensing data, difficulty in reusing sensing equipment, and difficulty in networking during coal mining process. A coal mining environmental safety warning and equipment posture decision-making system software is developed. It forms a coal mining safety decision-making system that integrates intelligent "fiber grating perception - dynamic response - precursor warning - safety decision-making". The analysis points out that the development of special material fiber optic products suitable for multiple scenarios, packaging technology suitable for coal mining needs, and demodulation instrument hardware that balances precision and cost will help to promote the application of fiber optic sensing technology in information perception in intelligent coal mining.

Research on the application of UWB radar in mine drilling rescue

WEN Hu, ZHOU Bo, ZHENG Xuezhao, KANG Yuguo, CAI Guobin, HUANG Yuan, DING Wen

2023, 49(6): 88-94. doi: 10.13272/j.issn.1671-251x.18095

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Abstract:
The ultra wideband (UWB) radar detection technology can achieve mine human target detection for drilling rescue. However, UWB electromagnetic waves are susceptible to the complex environment of catastrophic mines. The UWB radar echo signals are susceptible to the background clutter and environmental noise of catastrophic mines. It is difficult to achieve precise detection of human targets in catastrophic mines. In order to solve the above problems, the underground target detection scenarios and human target detection principles based on UWB radar are introduced. The research status of UWB electromagnetic wave characteristics and UWB echo noise filtering methods are analyzed. The existing problems are summarized as following points. ① The propagation characteristics of UWB electromagnetic waves in the complex environment of catastrophic mines require in-depth research. ② The reason for the generation of background clutter is not yet clear. There is limited research on the filtering technology of background clutter and environmental noise in catastrophic mines. ③ The UWB radar human target detection technology for drilling rescue still needs to be improved. In response to the shortcomings of existing technologies, the development trend of UWB radar underground human target detection technology for drilling rescue is prospected. ① It is suggested to do in-depth research on the sensitivity of key characterization parameters of UWB electromagnetic wave penetration transmission to complex underground environmental characteristics. ② It is suggested to construct methods for filtering background clutter and environmental noise suitable for catastrophic mines. ③ It is suggested to deeply optimize UWB radar human target detection technology for drilling rescue.

Research on full-life cycle gas treatment technology based on floor rock roadway

ZHAI Cheng, TANG Wei

2023, 49(6): 95-103, 167. doi: 10.13272/j.issn.1671-251x.18121

<Abstract>(758) <HTML> (50) <PDF>(24)

Abstract:
For mines lacking conditions for mining protective layers, pre extraction of coal seam gas from floor rock roadway strips is the mainstream gas control method. The analysis indicates that there are problems in the practical application of the floor rock roadway, such as significant differences in the selection of spatial layers, poor stability of the surrounding rock of the coal roadway caused by through layer punching, high excavation cost, and low utilization efficiency. Based on the floor rock roadway and considering the gas problem throughout the entire coal production process, a full-life cycle gas treatment technology based on floor rock roadway is proposed. It forms a five-in-one gas comprehensive treatment model of "layer optimization, through layer punching, layer grouting, mining extraction, and gangue backfill". Taking Shoushan No.1 Coal Mine as an example, by measuring the rock mechanics properties of the strata in the coal mining face, the stability of the floor rock roadway under the conditions of roadway excavation and mining face is analyzed based on the numerical method. Based on the characteristics of surrounding rock damage and the distribution of stress in the mining surrounding rock, it has been determined to arrange the bottom rock roadway at a position of 16 meters below the mining face transportation roadway and 1 meter inboard from the upper transportation roadway. The layout of hydraulic punching holes in the floor rock roadway is optimized. The group spacing is set to be 6.4 meters. The interleaving drilling is arranged by odd and even numbers for each group. By measuring the residual gas pressure of hydraulic punching holes, it is found that the effective influence range of hydraulic punching holes exceeds 4 meters. The hole gas concentration is high and the decline is slow. The strip pre-extraction effect is good. The though layer grouting technology is used to improve the properties of the upper broken coal body. The drilling observations show that the strength of the coal body after through layer grouting reinforcement is increased and the degree of fragmentation is decreased. The monitoring results of the deformation of the roadway side show that the overall stability of the surrounding rock of the roadway is good. The strength of the coal seam is increased. The monitoring results of the amount of drilling debris show that the grouting reinforcement range exceeds 5 meters, effectively reducing the risk of outburst in the roadway excavation. Through drilling through the floor rock roadway, the pressure relief gas extracted during the mining process of the working face is extracted. It is found that the effective influence range of mining is 50 meters in front of the coal working face. The gas extraction effect in the mining-affected area is good. The gas concentration in the air flow of the coal working face is reduced to below 0.45%, effectively reducing the gas concentration in the coal mining face. After the completion of mining, a method of backfill gangue in the floor rock roadway is designed to reduce the cost of gangue extraction and improve the utilization efficiency of the roadway.

The current status and development trend of post-disaster rescue life detectors

ZHENG Xuezhao, YANG Zhuorui, GUO Jun, CAI Guobin, WANG Baoyuan, KOU Zhizhe, XIAO Yongfu, ZHANG Xiaojun

2023, 49(6): 104-111. doi: 10.13272/j.issn.1671-251x.18125

<Abstract>(1118) <HTML> (32) <PDF>(35)

Abstract:
As a device for timely rescue after disasters, life detectors play an irreplaceable role in locating, exploring, and searching for living organisms. This paper analyzes the working principles, technical features, usage scenarios, advantages and disadvantages of the currently used life detectors. The detectors include radar life detectors, audio life detectors, infrared life detectors, and other types of life detectors. Combined with practical applications, this paper points out the problems of the above life detectors. ① The detection technology is single and the comprehensive integration is low. ② The detection methods are traditional and equipment intelligence is insufficient. ③ The parts of the detector are not standardized, making equipment maintenance difficult. ④ Some life detectors have a relatively large structure and are inconvenient to carry, which affects rescue efficiency. In response to the existing shortcomings and problems, the development trends of life detectors are proposed. ① It is suggested to improve the integration level of life detectors. It is suggested to design life detection devices that use multi-source fusion to collect information, and use multiple information sources to obtain and detect life information. ② It is suggested to improve the intelligence level of life detectors, give them partial autonomy in decision-making, and reduce errors in life detection caused by improper operation by operators. ③ It is suggested to design modular life detectors and develop relevant standard procedures to standardize the components of the same type of life detector. It will reduce the difficulty of repair and maintenance of life detectors. ④ It is suggested to improve the circuit board design precision of the life detector, fully utilize spatial structure, reduce volume and improve portability without reducing the functionality of the life detector.

Discussion on intelligent reflecting surface technology and its application in wireless blind spot coverage in coal mines

LI Shiyin, ZHANG Peng, MIN Minghui, LI Zhiwei, ZHANG Mengdi, XIAO Jiayang

2023, 49(6): 112-119. doi: 10.13272/j.issn.1671-251x.18137

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Abstract:
The existing wireless communication technologies in wireless blind spot coverage have challenges in non-line-of-sight scenarios in coal mines. In order to solve the above problems, a solution approach is proposed to introduce intelligent reflecting surface (IRS) into the wireless communication system in coal mines to achieve blind compensation of wireless signal coverage. This paper analyzes the causes of wireless coverage blind spots in coal mines, including closed mine environments characteristics, common non-line-of-sight scenarios, and safety constraints on transmission power and antenna settings. However, traditional wireless coverage blind spot solutions for underground coal mines have limitations in hardware deployment, maintenance costs, and technical implementation. They cannot truly meet safe and efficient communication needs of specific mining scenarios. IRS has significant performance advantages in achieving coverage blind compensation due to its low cost, low power consumption, easy deployment, and scalability. This paper introduces IRS technology from three aspects: hardware structure, auxiliary channel model and typical application scenarios (precise positioning, signal and energy simultaneous transmission, UAV communication, edge computing and physical layer security). This paper proposes the use of IRS technology to optimize underground wireless blind spot coverage. By deploying IRS reasonably in coal mines, it reduces the absorption and scattering of main signal components by walls, and utilizes the adjustable reflection characteristics of IRS to optimize signal propagation. It significantly improves signal strength and coverage range. The future research directions of IRS technology in underground wireless communication in coal mines are pointed out. The directions include energy management of IRS-aided coverage and blind compensation systems, IRS-aided underground communication based on artificial intelligence, application of new IRS technology, and flexible deployment of IRS.

Intelligent decision-making model of multi-behavior collaborative control in coal mine excavation

WANG Hongwei, QIE Chenfei, FU Xiang, LI Jin, WANG Haoran

2023, 49(6): 120-127. doi: 10.13272/j.issn.1671-251x.18114

<Abstract>(787) <HTML> (24) <PDF>(29)

Abstract:
Intelligent decision-making support for multi-behavior collaborative control in coal mine excavation is one of the core functions of the coal mine excavation working face. The optimal time series planning of multi-behavior collaborative control in excavation is the key to intelligent decision-making. In order to solve the problems of single control mode, solidification and poor collaborative operation capability of multi-behavior in coal mine excavation, an intelligent decision-making model of multi-behavior collaborative control in coal mine excavation is designed. It realizes the collaborative operation of multi-behavior in the optimal time series. Firstly, an intelligent decision-making method for excavation multi-behavior collaborative control is proposed. The feasible time series planning set and multi-objective optimal time series planning strategy for excavation multi-behavior are determined. Secondly, based on the regulations and process requirements of the excavation site, a set of excavation action events is determined. By analyzing the time relationship between two action events in the event set, a constraint matrix for the time relationship of excavation multi-behaviors is obtained. Thirdly, based on the transformation method of the time relationship constraint matrix, the multi-behavior time relationship constraint matrix of excavation is transformed into a time relationship constraint matrix. The feasible time series planning set of excavation multi-behavior is obtained. Finally, the solving functions for different excavation objectives are defined and the optimal time series for different excavation objectives is obtained. The experimental results show that the excavation robot can work collaboratively without interference according to the optimal time series planning results of the excavation action determined by the model under different excavation objects. The execution time of one working cycle of the excavation operation is basically consistent with the time calculated by the decision-making model.

Research status and prospects of perception technology for unmanned mining vehicle driving environment

HU Qingsong, MENG Chunlei, LI Shiyin, SUN Yanjing

2023, 49(6): 128-140. doi: 10.13272/j.issn.1671-251x.18115

<Abstract>(849) <HTML> (35) <PDF>(123)

Abstract:
The auxiliary transportation system for coal mine is an essential system for transporting personnel, important materials, and equipment in coal mine enterprises. Realizing unmanned driving in coal mine is an inevitable requirement for improving transportation efficiency and ensuring transportation safety, and is also the only way to implement the national coal mine intelligent construction deployment. The mine unmanned driving relies on accurate and real-time environmental perception. By using onboard perception devices such as LiDAR and millimeter wave radar, as well as collaborative perception supported by the Internet of vehicles, the precise and detailed perception of local vehicles and even the entire mine is achieved. A systematic review is conducted on the research status of unmanned driving environment perception technology in mines. It is pointed out that the special environment of coal mine will lead to varying degrees of degradation in the performance of mine onboard perception devices. The advantages and disadvantages of various onboard perception devices are summarized. The key technologies of mine unmanned driving environment perception are elaborated in detail. The technologies include single-sensor obstacle recognition methods based on visible light images or laser point clouds, the classification of multi-sensor fusion perception, and multi-sensor fusion methods such as visible light images+laser point clouds, visible light images+millimeter wave point clouds, visible light images+laser point clouds+millimeter wave point clouds, 4D millimeter wave radar+other perception devices. The technologies include the implementation, data processing methods of intelligent networked collaborative perception, and their promoting effects on unmanned driving. The technologies also include methods for detecting and recognizing traffic signs in underground roadways, and methods for segmenting the driving area of underground trackless rubber wheeled vehicles and tracked locomotives in roadways. The development direction of unmanned driving environment perception technology in mines is pointed out. It is recommended to improve the fusion performance of multiple sensors in mines, study adaptive perception algorithms in mines, and break through the intelligent networked collaborative perception technology in mines.

Design of intelligent mine low code industrial IoT platform

HE Yaoyi, CHEN Xiaojing, HAO Zhenyu, DING Lei, GAO Wen

2023, 49(6): 141-148, 174. doi: 10.13272/j.issn.1671-251x.18110

<Abstract>(788) <HTML> (40) <PDF>(56)

Abstract:
With the steady progress of intelligent mine construction and the acceleration of the implementation of digital transformation of coal enterprises, the demand for digital business applications of coal mine users is growing exponentially. This puts forward higher requirements for the efficiency of business application development. The traditional development model of application systems in the coal industry relies excessively on professional manufacturers. It has problems, such as long implementation cycles, high implementation costs and low resource reuse rates. It is difficult to meet the management requirements of coal mine users for rapid development of business applications. To solve the above problems, a design scheme of intelligent mine low code industrial IoT platform using the "model driven" development mode is proposed. Based on microservices technology, the platform architecture including the data acquisition layer, data processing layer, data storage layer, data release layer, human-computer interaction and application layer is designed. The operation platform at each level resolves the corresponding functions of the development platform configuration through a resolution engine. By designing data encoding and master data specifications, platform internal data interaction specifications, platform interfaces and services, a unified technical system has been established. The unified supervision of various IoT monitoring objects on coal mine operation sites is achieved. By developing a low code component toolbox, a series of common functions and business logic that originally needed to be customized and developed in various monitoring system software for coal mines are uniformly encapsulated. It forms directly reusable components that can adapt to different types of monitoring system applications in coal mines. This provides users with a visual development environment for intelligent mining application software development by dragging and dropping components and configuring parameters. The application results indicate that this platform can provide a rapid development platform for coal mine monitoring systems, meeting the daily needs of coal mine users for emergency customized task development.

Summary of fault diagnosis methods for belt conveyor systems

YANG Chunyu, CAO Boshi, ZHANG Xin, JI Mingjun

2023, 49(6): 149-158. doi: 10.13272/j.issn.1671-251x.2023030099

<Abstract>(941) <HTML> (211) <PDF>(80)

Abstract:
The conveyor belt and driving device are the main components of the belt conveyor and are the high-risk areas for faults. Taking conveyor belt faults and driving device faults as the starting point, this paper analyzes the mechanisms of conveyor belt deviation, slipping, damage, stacking and scattering, as well as the faults of the driving device roller, idler and reducer. It focuses on the research progress of knowledge-driven and data-driven fault diagnosis methods for belt conveyors. Based on the knowledge processing technology, the knowledge-driven method realizes the unification of symbol processing and numerical processing, the unification of reasoning process and algorithm process. It mainly includes expert system and fault tree analysis. The data-driven method uses machine learning and data mining techniques to analyze and process historical data. It establishes diagnostic models, and achieves fault diagnosis purposes. It mainly includes support vector machines (SVM), comparison method, and diagnosis methods based on sound and vision. This paper analyzes the current challenges and future development trend of belt conveyor fault diagnosis methods. ① The historical fault data and real-time data should be combined to infer equipment health. The early minor faults should be predicted so as to remind the staff to carry out predictive maintenance. ② The correlation between coupling faults of belt conveyors should be revealed. The emerging technologies such as artificial intelligence should be used to study joint diagnosis methods for coupling faults. ③ The multimodal machine learning technology should be utilized to study the mechanism of multimodal information fusion and utilization of belt conveyors. Fault diagnosis methods for multimodal information fusion of belt conveyors needs to develop. ④ The fault knowledge graph and the belt conveyor domain knowledge should be combined to realize the belt conveyor equipment fault tracking and fault early warning. Through the knowledge query, knowledge reasoning and auxiliary decision-making functions, the capability of fault handling and precise mining of potential fault risks of equipment can be improved.

Safety analysis of half wave oscillator structure in underground 5G radiation field

TIAN Zijian, JIANG Huangzhou, CHANG Lin, LIU Bin, WANG Wenqing

2023, 49(6): 159-167. doi: 10.13272/j.issn.1671-251x.2022100092

<Abstract>(780) <HTML> (26) <PDF>(21)

Abstract:
GB 3836.1-2021 Explosive atmospheres - Part 1: Equipment-General requirements stipulates that the RF threshold power of RF equipment in explosive environments shall not exceed 6 W. This regulation is derived from EU standards and lacks experimental verification, seriously restricting the application of 5G technology in mines. In order to reassess the safety of electromagnetic wave energy radiated by 5G communication equipment in mines, it is analyzed that the form of discharge generated by metal structures coupling electromagnetic waves should be low voltage breaking circuit arc discharge. The discharge energy generated by metal structures coupling electromagnetic waves is analyzed. The half wave oscillator structure that is most easily coupling with electromagnetic waves is selected as the research object. Through comparison, it is found that the discharge energy generated by the equivalent DC discharge circuit equivalent half wave oscillator is greater than that generated by the equivalent high-frequency discharge circuit. Therefore, the analysis of the safety of metal structure coupling electromagnetic wave discharge can be transformed into the analysis of the safety of the equivalent DC discharge circuit of equivalent half wave oscillator antenna of the metal structure. The safety judgment principle of intrinsically safe DC circuit is selected to judge the safety of the equivalent DC discharge circuit of equivalent half wave oscillator . By calculating the discharge power and energy, it is concluded that 5G RF equipment will not ignite explosive gas when its radiated power is not greater than 10.5 W. Therefore, the safe radiated power of RF base station of 5G communication system can be increased to 10.5 W.

Research on mine 5G network slicing technology

MENG Qingyong, JIANG Yufeng, LI Chenxin, ZHANG Liya

2023, 49(6): 168-174. doi: 10.13272/j.issn.1671-251x.18131

<Abstract>(864) <HTML> (32) <PDF>(34)

Abstract:
Network slicing is an important technology in 5G networks. The existing research on mine 5G mainly focuses on system architecture and application scenarios, lacking specific implementation solutions for slicing technology. In order to solve the above problem, by analyzing the basic structure of mine 5G networks and the application requirements of intelligent mines, it is proposed to use the channelization function of FlexE to achieve resource allocation and business isolation in the transmission network. It constructs multiple on-demand customized dedicated logical networks on the same network infrastructure, namely network slicing. According to the current applications of mine information communication systems and intelligent mines, a method of mine 5G network basic slicing+transmission resource allocation based on bandwidth weight is proposed. The network is divided into five types of slicing: low delay service, large bandwidth service, industrial ring network service, specific service (unmanned cooperative control) and reserved service. Through further virtual private network (VPN) division method, differentiated bandwidth weight is designed to ensure sufficient transmission resources and avoid channel congestion. The specific 5G QoS identifiers (5QI) are defined based on the requirements of different services for latency and bandwidth. The mapping and isolation based on 5QI are obtained to provide the required service levels for various businesses. Under laboratory conditions, two indicators of business scheduling time and end-to-end delay are tested for mine 5G network systems. The results show that network slicing can achieve more efficient business scheduling than traditional best-effort service models. In high-load scenarios, the average scheduling time is reduced by 10.9%. Within the same business slice, the average end-to-end delay of the mine 5G network is 10.33 ms, providing necessary conditions for the implementation of unmanned collaborative control and other services.

A path-planning method for coal mine robot based on improved probability road map algorithm

XUE Guanghui, LIU Shuang, WANG Zijie, LI Yanan

2023, 49(6): 175-181. doi: 10.13272/j.issn.1671-251x.18116

<Abstract>(957) <HTML> (27) <PDF>(27)

Abstract:
Path planning is a key technology that urgently need to be solved in application of coal mine robots in unstructured narrow confined spaces underground. The traditional probabilistic road map (PRM) algorithms are difficult to ensure uniform distribution of sampled nodes in free space in narrow and enclosed roadway environments, resulting in path planning failure. Nodes may be close to obstacles, resulting in poor passability of the planned path. In order to solve the above problems, a path-planning method for coal mine robot based on improved PRM algorithm is proposed. In the constructive phase, the artificial potential field method is introduced to push the node falling in the obstacle to the free space along the direction of the connection line of the node in the free space nearest to it. The repulsive force field is established at the edge of the obstacle to realize uniform distribution of nodes and make them a certain distance from the obstacle. In the query phase, the D^* Lite algorithm is integrated to achieve path re-planning when encountering dynamic obstacles or when the front is impassable. The simulation results show that the nodes of the improved PRM algorithm are uniformly distributed in free space and are at a certain distance from obstacles. It improves the safety of path planning. When the number of nodes is 100, the success rate of the improved PRM algorithm is 25% higher than that of the traditional PRM algorithm. As the number of nodes increases, the number of successful path-planning attempts for both traditional and improved PRM algorithms shows an increasing trend. But the improved PRM algorithm has a more significant advantage in efficiency. When the number of nodes is 400, the operational efficiency of the improved PRM algorithm is 35.13% higher than that of the traditional PRM algorithms. The planned path is smoother and the path length is shorter. When obstacles suddenly appear, the improved PRM algorithm can achieve path re-planning.

Adaptive control method for drilling robot based on coal and rock drillability

LI Wangnian, ZHANG Youzhen, TIAN Hongliang, LI Quanxin, WEI Hongchao

2023, 49(6): 182-188. doi: 10.13272/j.issn.1671-251x.2022110047

<Abstract>(1077) <HTML> (23) <PDF>(25)

Abstract:
Due to the complex geological and mechanical environment of coal-bearing strata, the feed resistance of the drilling rig feed system and the load torque of the rotary system are complex and diverse. The existing technology only controls the actuator through established procedures for procedural actions. The adaptive intelligent control level of the drilling process is low. When the drilling conditions change, it is easy to cause accidents such as sticking and breaking. It reduces the drilling efficiency of the drilling robot and affects the work cycle. To solve this problem, a dual loop PID adaptive control method for feed and rotation of drilling robots based on coal rock drillability is proposed. Firstly, with drilling efficiency and drilling safety as control objectives, drilling pressure and torque are selected as input parameters of the coal rock drillability model. Wavelet packet decomposition is used to extract features of drilling process data to obtain sample data and test set. BP neural network is used for training and verification to establish coal rock drillability model and obtain recommended drilling speed and rotation speed under current drilling conditions. Secondly, based on the coal rock drillability model, a constant torque control strategy and a constant drilling speed control strategy based on PID control are designed. The drilling robot feed rotation control system adjusts the set drilling pressure through a constant torque control circuit to achieve constant torque control. The system adjusts the set torque through a constant drilling speed control circuit to achieve constant drilling speed control, improving drilling efficiency while ensuring its safe operation. Finally, A drill-rock interaction model reflecting the feed swing load is developed. The simulation testing is conducted on the dual loop PID adaptive control method for the feed rotation of the drilling robot. The results show the following points. ① When the hardness of coal and rock remains unchanged, this control method can achieve constant torque and constant drilling speed control, with torque maintained at 2 000 N·m and drilling speed maintained at 6 mm/s. ② At 50 seconds, by increasing the hardness of coal and rock and adopting an adaptive adjustment strategy, the drilling robot can quickly reach a stable state in terms of drilling pressure, rotation speed for the rotary control system. ③ If the recommended drilling speed of 6 mm/s corresponds to an actual torque of 2 350 N·m which exceeds the permissible load torque for the operation of the drilling robot and the actual speed of 85 r/min is less than 95% of the recommended speed, the recommended drilling speed setting is reduced by means of the drilling speed trim module. The drilling pressure is adjusted to adjust the drilling robot's torque to the optimal torque, ensuring that the drilling robot is stable again in the constant torque and constant drilling speed control state.

2023 Vol. 49, No. 6

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