基于改进遗传算法的掘进机截割机构的多目标优化设计

掘进机截割机构的综合性能是由截割粉尘、截齿消耗量、截割比能耗、载荷波动及生产率决定的,基于改进的遗传算法,将截割机构的结构参数和运动参数作为设计变量,对截割机构的综合性能进行多目标优化设计。优化结果表明,掘进机截割粉尘、截齿消耗量、截割比能耗和载荷波动都相应有所下降,且生产率有着明显提高,有效地提升了掘进机的整机性能,符合了当今及未来掘进机的发展趋势。

悬臂式掘进机截割机构状态诊断策略研究

悬臂式掘进机工作中常会遇到煤层硬度突然变大,使截割机构发生异常,甚至导致截齿断裂、减速器齿轮受损、截割电机转子不平衡等故障。为了实现对掘进机截割机构运行状态的远程监控,在分析掘进机截割机构工作原理及重要部件频率特征的基础上,采用Hilbert-Huang分析方法,在MATLAB中仿真得到了四种不同状态下振动信号的频谱特征和能量特征,基于支持向量机算法设计了系统的多故障分类器,通过仿真测试验证了上述分类器能有效地诊断出系统的故障部件,为实现掘进机截割机构运行状态的远程监控奠定了基础。

悬臂式掘进机截割机构振动特性研究

悬臂式掘进机工作中常会遇到煤层硬度突然变大,使截割机构发生异常,甚至导致截齿断裂、减速器齿轮受损、截割电机转子不平衡等故障,为了实现对掘进机截割机构运行状态的远程监控,在分析掘进机截割机构工作原理及重要部件频率特征的基础上,提出了采用Hilbert-Huang分析方法的掘进机截割机构异常振动特性研究,在MATLAB中进行了仿真,得到了截齿断裂、减速器齿轮断齿、截割电机转子不平衡状态下振动信号的频谱特征和能量特征,为实现掘进机截割机构运行状态的远程监控奠定了基础。

EBJ-120(S1)型掘进机装载机构的改进使用

EBJ-120(S1)型掘进机具有稳定性好,截割面积大,结构紧凑,适应性好,机身矮,重心低,工作平稳,操作简单,检修方便等优点,但其链板机装载效果差,严重影响了掘进机的正常使用。介绍了EBJ-120(S1)型掘进机装载机构的改进使用,使其能更好地适应井下的生产需要,保证井下生产的顺利进行。

掘进机行走机构常见故障及对策

掘进机主要是以开凿平直地下巷道为主要工作任务的机械装置,其主要构成部分有行走机构、装运机构、转载机构以及工作机构几大部分。掘进机的行走机构是影响掘进机的生产安全和煤矿的生产效率以及设备的使用寿命的重要部件。本文主要是先了解掘进机行走机构的工作原理,研究掘进机在工作过程中常会出现的一些问题和故障,从而提出了一些改进和加强行走机构的对策。本文的研究可以为掘进机行走机构的正常运行做一定的参考和借鉴,是有一定的重要意义。

掘进机装运机构设计改进

旨在讨论掘进机装运机构的工作原理以及实际使用中存在的问题,总结出对掘进机第一输出机、液压系统、铲板部等的改进方案。

掘进机行走机构的设计要求探讨

本文以提高掘进机的行走性能为前提,对行走机构的设计要求进行理论分析和探讨。提出履带行走机构在掘进机中的各项功能后,明确了行走机构的工作原理和设计要求。对设计要求进行探讨后,进而选用行走机构不同要求的设计参数和结构型式,对不同功率掘进机的行走部进行三维建模设计和理论分析,从而提高掘进机在不同工况下掘进作业时的稳定性和适应能力。

全断面隧洞掘进机(TBM)在引黄工程中的应用

ＴＢＭ掘进机是目前世界上隧洞施工中最先进的掘进设备。引黄工程总干线６、７、８号隧洞已由它全线贯通，南干线长为８８的４、５、６、７号隧洞也即将由其施工。本文详尽地介绍了ＴＢＭ的构造、工作原理；从施工准备到掘进，衬砌、回填豆砾石及灌浆和出渣的施工过程；以及混凝土预制管片的设计与生产。讨论了ＴＢＭ在引黄工程总干线６、７、８号隧洞施工过程中遇到的溶洞、土层、错台、密封等问题及解决办法，最后对ＴＢＭ在不同地质情况，不同隧洞类型中的应用情况提出了自己的看法。

掘进机行走机构故障诊断的专家系统研究

通过对掘进机行走机构工作原理的分析,建立了故障树,探讨了掘进机行走机构专家系统的结构,利用“框架+产生式规则”相结合的方法,建立了知识库,采用正向推理的推理机制,建立了掘进机行走机构故障诊断的专家系统,所做的研究对于加快故障诊断速度、提高掘进机行走机构工作的可靠性有重要的理论意义。

Motion control of thrust system for shield tunneling machine

The thrust hydraulic system of the prototype shield machine with pressure and flow compound control scheme was introduced. The experimental system integrated with proportional valves for study was designed. Dynamics modeling of multi-cylinder thrust system and synchronous control design were accomplished. The simulation of the synchronization motion control system was completed in AMESim and Matlab/Simulink software environments. The experiment was conducted by means of master/slave PID with dead band compensating flow and conventional PID regulating pressure. The experimental results show that the proposed thrust hydraulic system and its control strategy can meet the requirements of tunneling in motion and posture control for the shield machine, keeping the non-synchronous error within ±3 mm.

The trend of mechanizing road header for coal mine entry

In discussing coal mine entry construction with rock bolt technology, examinedthe craft and machinery problems as well as the conditions in which to use each kind ofmachine and tool.It exposed the intrinsic flaws of the widely used road header.The problemis that it was designed according to early timbering support state but is not suitable forrock bolt technology.The way to improve the function of existing road headers is notthrough parallel operations but using the SUDM (Shield Union Driving Machine), which isa new machine that improves construction.This article proposed a few solutions in designto solve this problem.

Multi-degree-of-freedom coupling dynamic characteristic of TBM disc cutter under shock excitation

When the tunneling boring machine(TBM) cutterhead tunnels, the excessive vibration and damage are a severe engineering problem, thereby the anti-vibration design is a key technology in the disc cutter system. The structure of disc cutter contains many joint interfaces among cutter ring, cutter body, bearings and cutter shaft. On account of the coupling for dynamic contact and the transfer path among joint interface, mechanical behavior of disc cutter becomes extremely complex under the impact of heavy-duty, which puts forward higher requirements for disc cutter design. A multi-degree-of-freedom coupling dynamic model, which contains a cutter ring, a cutter body, two bearings and cutter shaft, is established, considering the external stochastic excitations, bearing nonlinear contact force, multidirectional mutual coupling vibration, etc. Based on the parameters of an actual project and the strong impact external excitations, the modal properties and dynamic responses are analyzed, as well as the cutter shaft and bearings' loads and load transmission law are obtained. Numerical results indicate the maximum radial and axial cutter ring amplitudes of dynamic responses are 0.568 mm and 0.112 mm; the maximum radial and axial vibration velocities are 41.1 mm/s and 38.9 mm/s; the maximum radial and axial vibration accelerations are 94.7 m/s2 and 58.6 m/s2; the maximum swing angle and angular velocity of cutter ring are 0.007° and 0.0074 rad/s, respectively. Finally, the maximum load of bearing roller is 40.3 k N. The proposed research lays a foundation for structure optimization design of disc cutter and cutter base, as well as model selection, modification and fatigue life of the cutter bearing.

Compliance of hydraulic system and its applications in thrust system design of shield tunneling machine

As the most significant performance, compliance of hydraulic system is defined as the capacity to accommodate the sudden change of the external load. Due to the different requirements of the compliant tasks, the existing method for mechanical systems cannot be used in the analysis and design of the hydraulic system. In this paper, the definition and expression of compliance of hydraulic system are proposed to evaluate the compliance of the hydraulic system operating under sudden change load. Because the unexpected geological conditions during excavation may exert sudden change load to the shield tunneling machine, the compliance theory has found a right application in the thrust hydraulic system. By analyzing the basic operating principle and the commonly used architectures of the thrust hydraulic system, a compliance based thrust hydraulic system design method is presented. Moreover, a tunneling case is investigated in the paper as an example to expound the validation of design procedure. In conclusion, the compliance of the hydraulic system can be served as an evaluation of the capability in conforming to the load impact, giving supports for the design of the thrust hydraulic system of shield tunneling machines.

Theoretical model for loads prediction on shield tunneling machine with consideration of soil-rock interbedded ground

The loads acting on shield tunneling machines are basic parameters for the equipment design as well as key control parameters throughout the entire operation of the equipment. In the study, a mechanical analysis for the coupled interactive system between the cutterhead and the ground at the excavation face is conducted. The normal and tangential loads acting on the cutterhead are decoupled and solved, with consideration of the influence of three key factors on loads: geological condition, operating status and equipment structure. Then analytical expressions for the thrust and the torque acting on the equipment under uniform geological condition are established. On this basis, the impact of soil-rock interbedded ground on acting loads is further considered. A theoretical model for loads prediction of earth pressure balance (EPB) shield machines working under soil-rock interbedded ground is proposed. This model is subsequently applied to loads prediction for a shield tunneling project under soil-rock interbedded ground. The computational value of the thrust and the torque, the measured loads and the load ranges from Krause empirical formula are compared. Thus, this model for loads prediction acting on shield tunneling machines under soil-rock interbedded ground has been proved to be effective.

A stiffness-matching based evaluation approach for compliance of mechanical systems in shield tunneling machines

As the most important performance,compliance of shield tunneling machines(STM) is defined as the capability to accommodate the sudden change of the load induced by the variable geological conditions during excavation.Owing to the different requirements of the compliant tasks,the existing methods in the robotic field cannot be utilized in the analysis and design of the mechanical system of shield tunneling machines.In this paper,based on the stiffness of the mechanical system and the equivalent contact stiffness of the tunnel face,the tunneling interface-matching index(IMI) is proposed to evaluate the compliance of the machine.The IMI is defined as a metric to describe the coincidence of the stiffness curves of the mechanical system and the tunnel face.Moreover,a tunneling case is investigated in the paper as an example to expound the validation of IMI and the analytical process.In conclusion,the IMI presented here can be served as an appraisement of the capability in conforming to the load fluctuation,and give instructions for the design of the thrust system of shield tunneling machines.

A new calculation model of cutterhead torque and investigation of its influencing factors

Cutterhead torque is a crucial parameter for the design and operation of earth pressure balance （EPB） shield tunneling machine. However, the traditional calculation models of cutterhead torque are too rough or exist gross errors under variable geological conditions. In order to improve the precision of the calculation model of cutterhead torque, dynamic operation parameters are considered and a new model is proposed. Experiment is carried out on a ~1.8 m shield machine test rig and the calculating re- sult with the new model is compared with the experimental data to verify the validity of the new model. The relative error of the new model is as low as 4% at smooth stage and is reduced to 5% at the end of trembling stage. Based on the results of the new model and the test data obtained from the 001.8 m test rig and the construction site, the inner relationships between several operation parameters and cutterhead torque are investigated and some quantitative conclusions are obtained.

Modeling and Prediction for the thrust on EPB TBMs under different geological conditions by considering mechanical decoupling

EPB TBMs(Earth pressure balance Tunneling Boring Machines) are extensively used in tunneling constructions because of its high efficiency and low disturbance on structures above ground. It is critically significant to predict the thrust acting on TBMs under different geological conditions for both the design of power system and the control of tunneling process. The interaction between the cutterhead and the ground is the core of excavation, through which geological conditions determine the thrust re-quirement combined with operating status and structural characteristics. This paper conducted a mechanical decoupling analysis to obtain a basic expression of the cutterhead-ground interactive stress. Then more engineering factors(such as cutterhead topological structure, underground overburden, thrusts on other parts, etc.) were further considered to establish a predicting model for the total thrust acting on a machine during tunneling. Combined with three subway projects under different geological conditions in China, the model was verified and used to analyze how geological, operating and structural parameters influence the acting thrust.

Method to avoid the structural interference of the thrust system of a shield tunneling machine

Several malfunctions of the shield tunneling machine （STM） caused by structural interference have been encountered in actual tunnel excavation. This paper is focusing on providing an effective method to avoid the structural interference based on making the reachable and the required workspaces of the thrust system match each other. The main structure of the thrust mechanism is analyzed, and coordinate systems are built up to describe the pose and workspace of the thrust mechanism. Constraint conditions are derived and the formulation of each constraint condition is carried out to facilitate the analysis of the reachable workspace of the thrust mechanism. Meanwhile, a reachable workspace determination algorithm is introduced based on interval analysis method. The mathematical model for determining the required workspace of the thrust mechanism is presented based on the analysis of the process when the STM excavates along a specific tunnel axis. Two applications are included to show how to avoid these problems by choosing reasonable parameters of the designed tunnel axis and the key structural parameters of the thrust mechanism based on workspace matching.