Evaluation of roof cutting by directionally single cracking technique in automatic roadway formation for thick coal seam mining

Automatic roadway formation by roof cutting is a sustainable nonpillar mining method that has the potential to increase coal recovery,reduce roadway excavation and improve mining safety.In this method,roof cutting is the key process for stress relief,which significantly affects the stability of the formed roadway.This paper presents a directionally single cracking(DSC)technique for roof cutting with considerations of rock properties.The mechanism of the DSC technique was investi-gated by explicit finite element analyses.The DSC technique and roof cutting parameters were evaluated by discrete element simulation and field experiment.On this basis,the optimized DSC technique was tested in the field.The results indicate that the DSC technique could effectively control the blast-induced stress distribution and crack propagation in the roof rock,thus,achieve directionally single cracking on the roadway roof.The DsC technique for roof cutting with optimized parameters could effectively reduce the deformation and improve the stability of the formed roadway.Field engineering application verified the feasibility and effectiveness of the evaluated DSC technique for roof cutting.

Development of Automatic Programming System for NC Laser Cutting of Chinese Characters

This Paper presents an automatic programming system developed for NC laser onning of Chinese charaCterswhich combines AutoCAD with NC Under Windows environment, and generates numerical controlled Programs by extracting outline (stroke) figures of Chinese Characters from outline character base, optimizing cutting routes, transferring them to AutoCAD for editing operations, such as rotation transfer, enlarging an mirroring, the system can transferto a laser cutting machine througy RS-232 series interface to accomplish laser cutting of large Chinese characters.

Automation of choice of instrumental equipment and study of thermo-stressed conditions of metal-cutting instrument

This article about possibility of automations of choice of instrumental equipment. In it described problems of choice of equipment, which are decided by means of mathematical model, developed on the base of finite element method.

Comparative study of model tests on automatically formed roadway and gob-side entry driving in deep coal mines

Automatically formed roadway(AFR)by roof cutting with bolt grouting(RCBG)is a new deep coal mining technology.By using this technology,the broken roadway roof is strengthened,and roof cutting is applied to cut off stress transfer between the roadway and gob to ensure the collapse of the overlying strata.The roadway is automatically formed owing to the broken expansion characteristics of the collapsed strata and mining pressure.Taking the Suncun Coal Mine as the engineering background,the control effect of this new technology on roadways was studied.To compare the law of stress evolution and the surrounding rock control mechanisms between AFR and traditional gob-side entry driving,a comparative study of geomechanical model tests on the above methods was carried out.The results showed that the new technology of AFR by RCBG effectively reduced the stress concentration of the roadway compared with gob-side entry driving.The side abutment pressure peak of the solid coal side was reduced by 24.3%,which showed an obvious pressure-releasing effect.Moreover,the position of the side abutment pressure peak was far from the solid coal side,making it more beneficial for roadway stability.The deformation of AFR surrounding rock was also smaller than the deformation of the gob-side entry driving by the overload test.The former was more beneficial for roadway stability than the latter under higher stress conditions.Field application tests showed that the new technology can effectively control roadway deformation.Moreover,the technology reduced roadway excavation and avoided resource waste caused by reserved coal pillars.

Study on Test Compaction in High-Level Automatic Test Pattern Generation (ATPG) Platform

Advancements in semiconductor technology are making gate-level test generation more challenging. This is because a large amount of detailed structural information must be processed in the search process of automatic test pattern generation (ATPG). In addition, ATPG needs to deal with new defects caused by process variation when IC is shrinking. To reduce the computation effort of ATPG, test generation could be started earlier at higher abstraction level, which is in line with top-down design methodology that has become more popular nowadays. In this research, we employ Chen’s high-level fault model in the high-level ATPG. Besides shorter ATPG time as shown in many previous works, our study showed that high-level ATPG also contributes to test compaction. This is because most of the high-level faults correlate with the gate-level collapsed faults especially at input/output of the modules in a circuit. The high-level ATPG prototype used in our work is mainly composed by constraint-driven test generation engine and fault simulation engine. Experimental result showed that more reduced/compact test set can be generated from the high-level ATPG.

STUDY ON THE CUTTING PROPAGATION TECHNIQUE OF PICEA KORAIENSIS

The cutting propagation technique of Picea koraiensis was carried under automatic spraytng of total sunlight by adopting the same year epicormic branches from different trees with different age treated by different hormones in different concentration and time and the orthogonal and randomized block was designed. The results were as follows : (1)The rooting rate of the cutting reached at least 87 percent, when the cuttings were from the seed tree with the age below 25 years old and the cuts of the cuttings base were in vertical angle and on the fine sand medium. (2) The sequence of effective factors affecting the rooting rate were the style of cut, the age of seed tree and the trpe of mediun. (3) There are significant differences of rooting rate among different clones.

Dynamics analysis on transverse cutting mechanism of straw checkerboard paving robot

The transverse cutting mechanism of the checkerboard paving robot, which directly affects the robot＇s operation, is regarded as the most important part in a transverse pavement system This research aims at designing a new system which is appropriate for desert wofidng en- vironments and finishing cutting the rope of straw. In this paper, computer emulating technology is applied, and with three-dimensional modeling by Pro/ENGINEER software, can observe whether or not interference exists. Also, the speed and displacement parameters of the main parts of the cutting system are given by the dynamic emulation by Automatic Dynamic Analysis of Mechanical System （ADAMS）, which theoretically assures the feasibility and appropriateness of the cutting mechanisrn~ Finally, results of the experinaent shows that the cutting mechanism can cut the straw strand as designed.

Research on the memory cutting path of shearer based on genetic algorithm

In order to realize the memory cutting of a shearer, made use of the memorizedcutting path and acquisitioned cutting parameters, and realized the teaching and playbackof the cutting path.In order to optimize the memory cutting path of a shearer, took intoaccount the constraints of coal mining craft, coal quality and the adaption faculty of coalmining equipments.Genetic algorithm theory was used to optimize the memory cutting ofshearer and simulate with Matlab, and realized the most valuable mining recovery rate.The experimental results show that the optimization of the memory cutting path of ashearer based on the genetic algorithm is feasible and obtains the most valuable memorycutting path, improving the ability of shearer automatic cutting.

数字孪生驱动的巷道自动成形截割虚拟调试方法研究

针对目前巷道自动成形截割控制调试周期长、调试成本大、安全风险大、成形质量难以评价等问题,提出了一种数字孪生驱动的巷道自动成形截割虚拟调试方法。采用基于即时外观建图(RTAP−MAP)技术重建巷道三维环境,构建掘进机控制系统模型,形成虚拟调试环境,并利用虚拟传感器技术实现物理空间到虚拟环境状态的精准映射。针对难以量化评估断面成形质量的问题,确立了巷道自动成形截割性能评价方法,以断面成形截割控制过程在数据传输中心的记录为基础,主要对断面成形精度、截割效率与油缸开关次数、硬岩切割调整、超挖欠挖4个评价指标进行计算,从而为深度学习算法的迭代优化提供精准反馈信号,并提出了一种融合强化学习的自动截割控制策略,以提高自动化作业的适应性和精确度。为验证该虚拟调试方法的有效性和准确性,搭建了掘进机自动控制实验平台,并将虚拟调试系统应用于掘进巷道成形截割自动控制程序中。虚拟仿真结果表明:①被调试软件在控制关键点位处的X,Y,Z轴定位误差的最大值分别为74.8,72.93,123.67 mm,说明虚拟调试方法的定位精度达到性能要求。②虚拟样机与物理样机轨迹基本一致,说明该调试方法实现了对物理空间的映射。应用结果表明:①强化学习控制器在虚拟掘进测试中适应了复杂环境,将虚拟传感器输入有效转换为精准控制指令,验证了模拟−现实迁移训练的可行性。通过处理掘进精度和避免超欠挖的实时反馈,控制器学习并优化了策略。②优化后的断面成形截割控制性能得到了提升,根据数据库中控制量时间戳的记录,用时126 s,较优化前耗时减少了8 s。③优化后截割部末端轨迹跟踪最大误差为6.0 mm,较优化前降低了0.3 mm,避免了截割轨迹抖动导致的欠挖,同时使得轨迹和断面更加平滑。

瓶栽鹿茸菇自动采收装置设计与试验

针对瓶栽鹿茸菇工厂化采收装备缺失的问题,提出了一种“输-定-切-夹”采收工艺,并设计了相应的自动采收装置,阐述了装置总体结构及工作原理,确定了整机作业流程。通过对栽培筐输送过程运动学与力学分析,确定了导流条安装角及输送辊筒参数;基于ANSYS LS-DYNA对切割过程进行了仿真分析,以切割速度、进给速度、带锯条前角及齿距为试验因素,以切割反作用力为响应指标,通过响应面法进行了切割性能建模和优化。结合物理试验确定了最优参数组合:切割速度为6.49 m/min、进给速度为0.12 m/min、前角为25°、齿距为7 mm;采用ABAQUS软件对柔性手指弯曲过程进行了仿真,结合物理试验确定了柔性手指最优结构参数为:气腔厚度2 mm、气腔7个、气压25 kPa、限制层厚度3 mm。整机试验表明,装置运行平稳,采收作业效果良好,平均采净率、平均损失率和平均损伤率分别为98.18%、3.66%和2.75%,满足瓶栽鹿茸菇实际采收要求。

小蚕饲育切桑机结构设计与性能分析

针对小蚕饲养过程中桑叶切割效率低下问题,文中设计了一种集自动切割、自动清理等功能于一体的自动切桑机。文中采用Solid Works建立了切桑机的模型,介绍了传动系统、切割机构和清理机构等主要结构的设计,并从桑叶切割大小、桑叶切割质量和桑叶切割效率3个方面对切桑机的性能进行分析,提出了一种通过控制刀具转速切割不同规格大小桑叶的方法,得出了切割1 cm×2 cm,1.5 cm×2 cm和2 cm×2 cm三种规格大小的桑叶所需的刀具转速、相对速度和切割效率,最高切割效率可达624 kg∕h。

简易等离子切割下料装置的设计与应用

针对常见的氧乙炔切割和空气等离子切割等热切割方式存在的成本高、危险性大的问题,基于空气等离子切割技术设计了一种简单的半自动钢板切割下料装置。该装置主要由等离子切割电源、供气系统、半自动高速等离子切割行走小车、柔性化等离子切割枪夹具、等离子切割工作台等构成,通过样机设计和实验验证改进对下料装置进行不断优化,实现了对带坡口焊接试板的切割下料,对从事焊接的操作人员的焊接技能训练提供了极大的便利,也为中小企业焊接作业员工培训节约成本。

油管外接管生产线送料切断控制系统设计

针对油管外接管生产过程中切断精确度低、废料率高,各设备相互独立及自动化程度较低等问题,在传统钢管切割设备的基础上优化设计了精确送料单元、锁紧切割单元、自动下料单元。基于S7-1500 PLC进行了油管外接管自动生产线控制系统的硬件及软件设计,利用TIA Portal设计控制逻辑,采用西门子KTP1200人机交互面板对生产线工作状态进行实时监控,实现对整机的协调控制。实验测试表明,所设计的油管外接管自动生产线自动化程度高、运行稳定,显著提高了油管外接管的生产效率与自动化程度。

通风管三通相贯线处焊接坡口自动切割机的研究与设计

通风管三通焊接前需要切割相贯线处的坡口,焊缝坡口的准备对后续焊接工作至关重要。同时,还设计了以液压传动及其控制系统为核心的通风管三通相贯线处焊接坡口自动切割机。其具有钢管夹紧力可控,快、慢速运动有效结合,提高了生产效率,保证了坡口切割质量,改善了工人劳动条件。液压传动及其控制系统的应用为钢管自动切割提供了必要条件,方案合理可行,机构简单紧凑,将具有广阔的应用前景。

基于数字孪生技术的煤矿掘进机自动截割方法研究

为了解决目前掘进工作面设备自动化控制存在的缺乏可视化人机交互控制、缺乏掘进工作面数字孪生动态建模、缺乏巷道模型与掘进机定位导航系统融合的问题,提出一种基于三维数字孪生技术的煤矿掘进机自动截割方法;该方法利用三维数字孪生技术的巷道模型生成截割模板,实现掘进机对预设截割断面的自动化截割,可达到人工远距离、可视化控制掘进机安全自动作业的目的。介绍了数字化巷道和掘进机模型的构建方法以及数据驱动逻辑,并对掘进机自动截割控制方法进行了详细阐述。结果表明,该方法避免了粉尘等对掘进机自动化截割的影响,降低了人员现场作业风险和劳动强度,解决了掘进机远程截割精确度低、巷道断面成型质量差等问题。

用Normalized Cut法自动提取乳腺超声图像中的肿瘤边缘

提出一种带权重邻域灰度信息的normalized cut(Ncut)方法,该方法能够全自动提取乳腺超声图像的肿瘤边缘.通过Ncut分块乳腺超声图像中的各块灰度及空间分布特征来识别待检测肿瘤的轮廓.对于少数分割不精确的结果,可用结合局部能量项的动态轮廓模型对所提取的初始边缘进行修正,使其更接近真实目标轮廓.对包含112幅乳腺肿瘤超声图像的数据库进行边缘提取,结果表明:该方法无需人工干预,能够准确有效地实现肿瘤分割,且计算量小,有望提高计算机辅助诊断的自动化程度.

悬臂掘进机自动截割路径研究

基于常村矿2106工作面地质条件进行掘进机自动截割路径研究分析,建立矿井自动截割理论,即确定矿井采用“S形”截割方式,阐述特征点控制断面边界的方法,断面自动截割距离路径等,并针对矿井不同岩性条件,通过理论分析确定硬岩和软岩截割块体边长分别为2.97 m和3.50 m,相关研究结论可为矿井掘进机在多条件下巷道掘进施工提供理论依据。

厚煤层大采高智能化综采工作面关键技术研究与应用

针对付村煤矿井下综采装备落后、开采成本高的问题,综合考虑生产安全、经济效益、资源回收等多方面因素,提出了在付村煤矿建立厚煤层大采高智能化工作面的构想。根据付村煤矿3上煤层赋存条件,基于智能化工作面设备集成控制平台,结合大采高液压支架智能化电控系统、大采高采煤机智能化控制系统及移动互联网云存储系统,重点突破了工作面主要设备姿态监测、大采高工作面智能化开采工艺、远程控制与集中监控等技术,实现了采煤机自主定位、记忆截割、液压支架自动跟机移架、全工作面一键顺序启停、故障自动顺序停机、三机协同控制,优化升级了矿井信息化系统,建立了智能化综采工作面互联网云平台。结果表明:自2017年11月在付村煤矿3上1008工作面进行工程应用以来,工作面生产班工作人员从12人减少为5人巡视检查,减员率达50%以上,日采煤达6000 t,技术应用效果显著,建立了枣矿集团6 m厚煤层智能化开采的生产模式,为厚煤层大采高智能化生产系统的发展提供示范与实践基础。

基于截割顶底板高度预测模型的采煤机自动调高技术

传统的煤层截割路径规划通过几何控制、规划计算等方式对采煤机滚筒高度进行预测,但存在预测的数据误差较大、无法适应地质条件变化的问题。针对上述问题,提出了一种基于截割顶底板高度预测模型的采煤机自动调高技术。首先,分析了影响截割顶底板高度的因素,指出影响顶底板高度的主要因素包括煤层的起伏变化数据、历史截割数据、刮板输送机的高程数据及人工操作记录,将上述4类数据融合处理,建立以长短期记忆(LSTM)模型和灰色马尔可夫模型为基础的截割顶底板高度预测模型,通过算法模型预测出截割顶底板的高度。然后,以截割顶底板的高度数据为基础,结合采煤机位姿和空间坐标,建立计算滚筒高度的几何模型,同时依据刮板输送机上窜下滑量及是否执行加减刀工艺等因素进行修正,最终将顶底板高度序列转换为滚筒高度序列,即将截割顶底板高度转换为采煤机滚筒的目标高度,由采煤机执行到目标高度,实现滚筒自动调高工业性试验结果表明:(1)在自动调高技术的控制下,顶滚筒和底滚筒的预测高度与实际高度偏差值有90%的数据量均在10 cm以内,滚筒的预测高度和实际高度具有明显的一致性。(2)与传统手动控制方式相比,中部截割一刀煤的人工干预调高次数由49次下降为21次,说明截割顶底板的高度预测模型和计算滚筒高度的几何模型是准确合理的,采煤机滚筒的自动调高技术是可行的。

Model-driven path planning for robotic plasma cutting of branch pipe with single Y-groove based on pipe-rotating scheme

The automatic cutting of intersecting pipes is a challenging task in manufacturing.For improved automation and accuracy,this paper proposes a model-driven path planning approach for the robotic plasma cutting of a branch pipe with a single Y-groove.Firstly,it summarizes the intersection forms and introduces a dual-pipe intersection model.Based on this model,the moving three-plane structure(a description unit of the geometric characteristics of the intersecting curve)is constructed,and a geometric model of the branch pipe with a single Y-groove is defined.Secondly,a novel mathematical model for plasma radius and taper compensation is established.Then,the compensation model and groove model are integrated by establishing movable frames.Thirdly,to prevent collisions between the plasma torch and workpiece,the torch height is planned and a branch pipe-rotating scheme is proposed.Through the established models and moving frames,the planned path description of cutting robot is provided in this novel scheme.The accuracy of the proposed method is verified by simulations and robotic cutting experiments.