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Abstract As one of the key components of the belt conveyor, the roller bears the task of supporting and rolling the conveyor belt, and monitoring its condition is very important. The traditional monitoring of the conveyor roller group adopts worker inspection, which has strong subjectivity. Monitoring using sensors necessitates the use of numerous sensors, which can pose wiring challenges. The use of inspection robots for monitoring results can be discontinuous, and their performance may be limited. This study proposes a fault diagnosis method for rollers based on a distributed fiber optic sensing system. By improving the traditional Isolation Forest (IForest), a framework called Incremental Majority Voting Isolation Forest (IMV-IForest) is proposed. By analyzing the optical signal, we extracted the variation patterns of roller faults over time and space, and analyzed the abnormal score distribution between fault data and normal data. Using the dataset collected on-site, we compared and analyzed IMV-IForest with the traditional IForest and the Extended Isolation Forest (E-iForest). The results indicate that the variation of the fault of the faulty roller with time and space can be used for early prediction of roller faults; determine an anomaly score threshold of 0.6; improved IForest have faster computation time and higher accuracy. Finally, to verify the effectiveness of the proposed scheme, a 3-month experiment was conducted on a 600 m long belt conveyor in a certain mine, and on-site monitoring results were obtained. By comparing with manual detection results, it was shown that the proposed method has high recognition rate for faulty idlers, with an accuracy rate of 97.92%, and can effectively diagnose faulty idlers.

Abstract A new type of parallel operation unit for excavating and supporting anchors is proposed to address the issue of imbalanced excavation anchor ratio in coal mines. By equipping a straddle type anchoring drilling rig group, the synchronous parallel and fast operation mode for excavating and supporting anchors is achieved; Consider the problem of poor drilling stability of drill pipes in coal mines due to the coupling vibration between surrounding rock and anchoring equipment. Firstly, taking the multi drilling rig anchoring system as the research object, considering the influence of the equipment itself as an influencing factor on the vibration of the drill pipe, a dynamic model of the system is constructed using Lagrangian equations, and analytical solutions for the vibration displacement of each mass block are obtained; In order to more intuitively represent the vibration process of the drill pipe, Ansys is used to conduct modal analysis on the key components of the anchoring drilling rig system, and obtain the natural frequencies and vibration modes of each order of the key components; Using Adams to solve the rigid flexible coupling dynamic model of the anchoring drilling rig system, the vibration response laws of the drill pipe under different operating states were obtained. Secondly, Abaqus was used to simulate the drilling process of the drill pipe and obtain the vibration response law generated by the interaction between the drill pipe and the surrounding rock; The results indicate that the anchoring equipment has a greater impact on the vibration of the drill pipe, and the surrounding rock has a more stable impact on the vibration of the drill pipe. Due to the short body and large span structure of the anchoring system crossbeam expansion frame, the vibration response of the drill pipe is significantly greater than that of the retracted state of the drilling rig due to being in an unstable cantilever state when the drilling rig is extended. The theoretical reliability of the vibration response law of the drill pipe under different states has been further verified through drilling experiments of the anchoring system prototype. The relevant theories can provide a theoretical basis for the implementation of automatic anchoring technology in the anchoring system.

Abstract The cutting process of the cantilever tunneling machine mainly generates excitation through the cutting motor or the hydraulic cylinder driven by the hydraulic system. Regardless of the driving method, the frequency width of the excitation system is limited, difficult to control, and the excitation effect is poor. Therefore, in order to improve excavation efficiency, the excitation system parallel to the original cutting and rotating system is designed. Based on the excitation characteristics caused by alternating fluid flow, the core component of the excitation system, hydraulic exciter, is designed, and the dynamics and dynamic characteristics of the excitation system are analyzed. Based on AMESim software, analyze the impact of factors such as pump displacement, excitation frequency, and pipeline parameters on the operational performance of the electro-hydraulic vibration cutting system, and conduct experimental verification by building a cutting test bench. The experimental results show that as the inner diameter of the pipeline increases, the fluctuation at the acceleration turning point decreases in each cycle and approaches the peak faster. As the excitation frequency increases, the cutting acceleration of the electro-hydraulic excitation cutting system decreases first and then increases, verifying the accuracy of the simulation results. In the experiment, it was found that the acceleration transformation range of the cutting head of the excitation system is the smallest and most stable when the excitation frequency is 30 Hz. In order to verify that the excitation frequency of 30 Hz is the optimal frequency, further contact force tests were conducted on the cutting teeth. It was found that when the hydraulic excitation system adds a 30 Hz excitation frequency, the contact force on the cutting teeth is the smallest. It is more conducive to reducing the damage and wear of the cutting head, and the cutting effect of the cutting head is more obvious. The research results are beneficial for improving the cutting performance of the electro-hydraulic excitation cutting system, providing theoretical support for the selection of cutting parameters for excavation machinery and hydraulic excitation, and improving the existing theoretical system for active excitation cutting vibration analysis of excavation machines.

Abstract High-efficiency rock breaking technology is an important problem to be solved urgently in deep mining. The existing auxiliary rock breaking technology for coal mine excavation has problems such as polluting coal, high requirements for tool materials, and difficulty in subsequent washing. In this paper, an active excitation cutting system for rotary cylinder of cantilever roadheader based on alternating valve is proposed. According to the classical calculation formula of cutting load of roadheader, considering the stiffness-damping characteristics of cutting part and cutting cylinder, the simulation algorithm of cutting load is compiled based on MATLAB simulation analysis software. The excitation cutting experiments of different cutting depths are carried out on the cutting test bench, and compared with the simulation algorithm of cutting load. Taking the cutting load as the discriminant index, the influence of oil supply pressure and excitation frequency of rotary cylinder on the cutting load is analyzed based on the simulation algorithm of cutting load. The results show that the error between the simulation results and the experimental results of the active excitation state is less than 12%, and the two are in good agreement. Under the condition of 30 HZ, when the excitation amplitude is 8 Mpa, 10 Mpa, 12 Mpa, 14 Mpa, when the rotary cylinder excitation amplitude is 10 Mpa, the minimum is 131.42 KN. Compared with the rotary cylinder excitation amplitude under the condition of 10 Mpa, when the excitation frequency is 30 HZ, 35 HZ, 40 HZ, 45 HZ, when the excitation frequency is 40 HZ, the minimum is 83.08 KN, indicating that changing the excitation amplitude or oil supply pressure of the rotary cylinder is helpful to adjust the cutting performance.

Abstract Aiming at the imbalance problem of excavating and anchoring efficiency ratio in the underground coal mine, a new type of parallel operation unit of excavation-supporting-anchoring is proposed to improve the excavating efficiency. Considering the uneven factors of the roof and floor of the coal mine roadway, the influence of different drilling angles and leg support angles on the leg support force is studied under the condition of simultaneous drilling of multiple drilling rigs. The results show that the maximum support force is 4.002 KN when the leg angle is different and the drilling angle is different. By constructing the coupling vibration model of the multi-drill drilling process and using the Lagrange method to solve the vibration law of key components of the anchorage system, the vibration law of drill pipe under different influencing factors such as cantilever extension, multi-drill simultaneous drilling, and drilling incident angle is studied. The results showed: (1) The vibration of the drill pipe in the cantilever extension state is more severe than that in the retracted state, and the maximum vibration peak reaches 7.61 mm. (2) The vibration response of the drill pipe is the most intense under the condition of four top anchor drilling rigs drilling at the same time. Under the working condition of only two drilling rigs, the vibration response of the drill pipe is the smallest. (3) As the drilling angle of the drilling rig increases, the vibration response of the drill pipe is more severe and the vibration amplitude is larger. A test prototype is built to simulate the actual anchoring drilling process, and the vibration law of the support platform and the drilling rig is obtained through the vibration detection system. The test results show that the vibration law of the key components is approximately the same as the theoretical simulation results. The relevant theoretical results can provide a technical basis for the drilling stability of the anchoring system.

Abstract In order to study the influence of the multiple interaction of coal and rock and the velocity effect of the cutting head on the flutter stability of the cantilever roadheader, considering the physical characteristics of coal and rock, the structural parameters of the cutting head and the motion parameters of the cutting head, the functional expression of the cutting depth of the cutting head and the participating cutting teeth is fitted, the cutting state mechanical characteristic equation of the dynamic cutting of the cutting teeth is established, and based on the mapping relationship between the cutting teeth and the cutting head, a cutting dynamic model including multiple interactions between cutting head and coal and rock and the speed effect is constructed. An improved discrete method based on Newton–Lagrange mixed interpolation is proposed, and the influence law of the coupling effect of regeneration effect and velocity effect on the stability of cutting flutter under cutting state is clarified. The improved full discrete method is compared with the full discrete method and the semi-discrete method, and the superiority of the improved full discrete method based on the mixed interpolation method is proved. Based on the improved total discrete method, the influence of different cutting system dynamic parameters on the stability is studied. A cutting head coal rock system is built to simulate the flutter of the cutting system. The results show that the improved fully discrete method can reasonably predict the actual cutting state.

Abstract Considering that the movement trajectory of roadheader cutting head directly affects the surface morphology characteristics of roadway forming, the creation mechanism of roadway contour obtained by cutting head cutting roadway is analyzed. The robot kinematics analysis method was used to determine the coordinates of the roadheader cutting head in the roadway space coordinate system, and the mathematical model of the cutting head cutting the roadway contour was constructed. Through numerical calculation, the differences of roadway morphology characteristics formed by three different types of cutting heads are analyzed. The orthogonal experiment was designed, and the regression equation under multiple factors was solved with the experimental results. The influence of cutting feed rate, cutting Angle, cutting head radius and cutting head cone Angle on the morphology characteristics of cutting surface was analyzed by regression calculation and theoretical calculation. The research results show that the roadway surface obtained by "spherical crown + cylinder" cutting head is the most uneven, and the roadway surface obtained by "spherical crown + cone + cylinder" cutting head is the most flat. With the decrease of cutting lifting Angle, cutting feed, cutting head cone Angle and the increase of cutting head crown radius, the smoothness of roadway obtained by cutting is higher.