现代数控机床PLC相关故障诊断及维修

PLC作为现代数控机床控制系统的一部分,在CNC与机床之间发挥控制功能.在实践应用中,它能够响应输入的离散信息,并在系统内部进行逻辑运算,最后作出针对性的动作.数控机床中的LPC,能够及时发现系统潜在故障,并对故障产生原因予以诊断,为维修人员维修提供支持.文章从PLC技术内涵及信息交换方式入手,并对现代数控机床PLC故障诊断及维修进行分析和研究.     

数控机床故障诊断方法与华中系统故障实例分祈

数控机床在使用过程中难免出现故障，本文在分析华中世纪星系统特点和功能的基础上，介绍了数控机床故障排除的思路和原则，针对华中世纪星系统常见的一些的故障进行了分析和处理，总结了数控机床故障诊断与维修的一般方法。     

仿真系统中的通用NC代码处理

一、前言在实际加工生产中，参与数控加工的主体是数控机床，而数控机床主要由四个主要部分构成，如图1所示。图 1 数控机床的组成其中伺服机构和机床本体是数控机床的硬件基础，决定了该类型的数控机床的功能。而数控装置作为数控机床的“指挥系统”，是数控机床最重要的组成部分。数控系统严格按照从外部输入的程序（NC代码）来指挥数控机床的硬件自动地对工件进行加工。在实际CNC加工生产中，由于机床的类型和生产厂家不同，其配备的CNC系统也是各不相同，因此虽然NC代码格式有国际标准，但各CNC系统的生产商各有一套标准，不同型…     

国产嵌入式操作系统故障监测系统设计

为了更及时地发现并解决嵌入式操作系统中发生的故障,设计并实现了一种基于国产嵌入式操作系统的故障监测系统。该系统主要由核心硬件失效监测、软件故障监测及日志管理三大模块构成。该系统通过监测功能发现故障,利用诊断功能分析故障,通过日志管理功能存储故障信息,最后调用故障处理功能处理故障并打印故障信息。测试结果表明,系统可快速监测到故障发生并诊断出正确的故障信息,使用人员获取到故障信息后即可对故障原因进行分析并对故障进行定位,从而方便地处理故障。     

长期在轨推进系统故障诊断实时仿真技术研究

为了解决长期在轨航天器易出现故障的推进系统故障常规地面检测费时费力且无法完全包络全部故障模式的问题,提出了长期在轨推进系统故障诊断实时仿真技术方案,建立了长期在轨推进系统故障诊断实时测试平台。通过建立推进系统实时仿真模型,实现对长期在轨推进系统的实时仿真;依托实时测试平台对推进系统故障诊断策略进行仿真优化、对在轨飞行器故障进行诊断、并对处置预案进行验证支持故障处置决策。长期在轨推进系统故障诊断实时测试平台有效缩短了器上故障诊断策略的优化迭代周期,同时节省了大量原本用来进行试车的经费。     

基于BFGS的遗传算法在数控机床故障识别研究系统中的应用

提出基于BFGS的遗传算法应用于数控机床故障识别研究系统,该算法与遗传算法、粒子群算法的函数测试比较结果表明其具有较高的收敛速度和较佳的计算性能,与遗传算法、蚁群算法的实例仿真比较结果表明其在数控机床故障识别研究系统中具有较好的性能.基于BFGS的遗传算法既具备遗传算法的全局搜索能力也提高了收敛速度,避免了早熟现象,可以较好地应用在数控机床故障识别研究系统中.     

关于数控自动编程加工的后处理问题

当前制造业在应用数控技术中,越来越多的人员开始使用CAM系统实现自动加工。CAM系统的使用通常会遇到一些关于如何生成被数控机床接受的后处理程序问题。例如,如何定位数控机床,使其能按照在CAD中建立的模型准确加工;如何按照不同的机床控制系统定义不同的处理程序,即如何生成符合自己使用要求的数控NC文件;如何实现与数控机床的文件传输等。通常CAM软件处理问题的过程如下:三维造型→生成刀路NCI文件→符合各种CNC机床控制系统要求的NC文件。这就是说,NCI文件是一个过渡性文件,最终起作用控制机床的是NC文件,也就是符合各种CNC…     

FANUC系统基于自诊断功能的参数故障分析与处理

数控机床参数的正确性直接决定着数控机床的功能与性能;数控机床在使用过程中,难免会出现参数的丢失、错乱或者人为因素的破坏;这必然会导致机床无法正常运行;在出现类似故障时,要迅速准确查明故障的原因和部位,从而快速排除故障;分析了FANUC系统参数的具体形式和常见参数故障,灵活运用现代数控系统丰富和完善的自诊断功能;通过具体实例,给出了利用自诊断功能对参数故障进行检查、分析与排除的方法;这种方法不需要借助于诊断仪器,能够快捷有效地对参数故障进行诊断和处理,可以广泛应用在现代数控机床的维修中。     

基于RS232通信接口的DNC方案

一、引言 数控机床与计算机通信是实现制造设备集成控制和管理的基础和必备条件。利用通信技术实现计算机对数控机床的直接或分布式集中控制称为DNC(Direct/Distribute Numberical Control)。围绕DNC技术,CNC制造商进行了长期深入的研究。通常,低     

一种便携式信号电缆接地故障检测仪

铁路信号室里信号线的数量众多,如何准确定位芯线接地故障的位置是个亟待解决的问题；文章针对故障芯线阻容网络的接地模型,提出了单频幅相法的故障定位方法,即用故障芯线各个测试点的幅相信息来确定故障点的位置,并且为了解决单频幅相法操作上的局限性,提出了基于折合相位差的双频幅相法定位原理；介绍了一种以TMS320C5509A数字信号处理芯片为数据处理和控制核心的便携式信号电缆接地故障检测仪,给出了该系统的工作原理及硬件、软件实现方案；经实验室测试及系统联调,实验室条件下用信号发射装置和信号接收装置对模拟故障电缆进行测试,测试结果表明,设计的测试系统能够定位1 MΩ接地电阻故障；该仪器达到了一定的精度,能较好地适用于工程现场的测试。     

基于CRIO的数控机械在线监测诊断系统设计

目前提出的数控机械在线监测诊断系统温度采集准确度较低,导致诊断过程稳定性及准确性较差,为此基于CRIO设计了一种新的数控机械在线监测诊断系统,以期更好地分析数控机械的运行状态;通过数控机床在线监测模块、远程设备管理模块及故障诊断模块组成系统总结构,硬件设备包括NTI CRIO驱动器、新型伺服电动机、采集卡、传感器以及PC上位机,设计多参数在线监测模块、网络控制模块、设备管理模块和故障诊断模块;在采集信号中提取数控机械运行状态数据,通过格拉布斯准则估算标准偏差,去掉误差数据后,输出有效数据,完成数据的采集及存储,实现数控机械在线监测诊断系统设计;实验结果表明,基于CRIO的数控机械在线监测诊断系统的温度采集准确率为99%,振动信号采集准确率为95%,可以有效提高采集精准度,增强数控机械在线监测诊断系统的准确性及稳定性。     

Software-based tool path evaluation for environmental sustainability

Currently available life cycle assessment (LCA) tools provide only a rough estimation of the environmental impact of different manufacturing operations (e.g. energy consumption). To address this limitation, a web-based and application programming interface (API) based process analysis software tools were developed to estimate the energy consumption of a computer numerically controlled (CNC) machine tool operation and to evaluate its environmental impact as a first step towards sustainable manufacturing analysis. Acceleration/deceleration of machine tool axes and the direction of axes movement were considered to estimate the total energy demand and processing time of the machine tool operation. Several tool path generation schemes were tested to analyze the energy consumption and resulting green house gas emission of CNC machine tool operation. It showed that tool path generation schemes affect the amount of energy and the processing time required to machine the same part, and location of the machining resulted in different amount and characteristics of green house gas emission.     

数控机床手轮进给故障的排故思路

在数控机床加工过程中,由于调整及慢速对刀的需要,通常需要频繁地使用手轮（即手摇脉冲发生器）来控制数控机床伺服轴的运动,因此,在数控机床的诸多故障中,手轮出现故障的次数较多,同时对该故障维修人员的维修水平要求也相对要高。本文以配备有FANuc 0i—mate-TD数控系统的cK0625数控车床为例,系统地介绍了数控机床手轮故障的诊断与分析方法。     

基于数据库的数控机床故障诊断专家系统

该文研究数控机床故障诊断专家系统的开发与设计思路。运用故障树分析法FTA（Fault Tree Analysis）建立数控机床主要故障部位的故障树．通过Access建立故障数据库,并采用Visual Basic6．0来开发设计数控机床故障诊断系统,可为机床故障诊断与维修提供帮助。     

Scheduling with tool changes to minimize total completion time under controllable machining conditions

Scheduling under controllable machining conditions has been studied for some time. Scheduling with tool changes, particularly due to tool wear, has just begun to receive attention. Though machining conditions impact tool wear and induce tool change, the two issues have not been considered together. We address for the first time the problem of scheduling a computer numerically controlled (CNC) machine subject to tool changes and controllable machining conditions; our objective is to minimize the total completion time of a given set of jobs. We establish an important result that helps us identify feasible settings of machining parameters such as feed rate and cutting speed. However, the problem at hand remains intractable, even when a single setting is used. In the general case, we are able to solve the problem exactly for up to 30 jobs using a mixed integer linear programming formulation. For larger problems, we turn to approximate solution via heuristics. We examine a number of different schemes. The best of these schemes are used in a problem space genetic algorithm; this produces quality solutions in a time-efficient manner, as is evidenced from an extensive computational study conducted by us.     

Intelligent automation of design and manufacturing in machine tools using an open architecture motion controller

Several issues including accurate programming, proper tool selection, machining feeds and speeds selection, thermal error compensation, vibration monitoring, etc. contribute significantly to the performance and productivity of a machine tool in an industrial scenario. Only when all these are properly set and controlled it is possible to ensure consistent accuracy and productivity of the machine tool. Significant developments have been made in enhancing the capabilities of a commercial computer numerically controlled (CNC) machine to address this challenge. In this paper, an attempt is made to present the concept of Rapid-Computer Aided Manufacturing (Rapid-CAM) using intelligent automation of a machine tool in order to address the above scenario through a real-time open architecture motion controller as well as to illustrate some of the features that are being implemented in a 3-axis vertical machining centre (VMC).     

双焊枪自动焊接机数控系统设计

针对散热器多T型管相贯线的连续焊接问题,提出了一种基于PC机和6K运动控制器的双焊枪自动焊接机数控系统。采用"PC+多轴控制器"的上下位机控制结构,上位机采用VisualBasic编制控制程序,实现系统的管理、控制功能。下位机采用6K4控制器独有的6000运动语言开发底层的伺服驱动程序,并可由上位机通过以太网接口调用。整个系统能够完成各轴状态实时显示、故障自动诊断、焊接路径规划、焊接参数调节等任务。     

Retrofitting machine tools with computer control

Many numerically controlled machine tools used in industry predate the era of microelectronics, and rely on controllers based on discrete logic. There are clear advantages in converting these machine tools to computer control. Part programmes can be loaded from a central library over a local area network, and status information can be returned to a central point to help with overall planning. A screen near the machine tool can display helpful information for the operator. Finally, computer control opens the way to integrating the machine tool into a flexible manufacturing system where human operators are partly or completely replaced by robots. This paper describes a simple and automatic way of converting a machine tool to computer control. The method relies on a commercially available microcomputer, and it can be applied to most existing numerically controlled machine tools with a minimum of disturbance.     

基于状态监测的高档数控机床智能保障系统研究

为了分析数控机床故障产生的原因,以研究制定相应的解决方案,同时为了实现设备运行状态的监控,并提高设备的可靠性,开发了集机床状态监测、故障预警、故障诊断和故障排除功能为一体的智能保障系统。通过对数控机床智能保障系统的研究和设计,展示了其实现的关键技术及方法。以丝杠运动状态监测为例,进行了运动状态趋势分析和智能故障诊断,从而实现了对数控机床的智能保障,并验证了该智能保障系统的实用性。     

Efficient time-optimal feedrate planning under dynamic constraints for a high-order CNC servo system

In this paper, the time-optimal feedrate planning problem under confined feedrate, axis velocity, axis acceleration, axis jerk, and axis tracking error for a high-order CNC servo system is studied. The problem is useful in that the full ability of the CNC machine is used to enhance the machining productivity while keeping the machining precision under a given level. However, the problem is computationally challenging. The main contribution of this paper is to approximate the problem nicely by a finite-state convex optimization problem which can be solved efficiently. The method consists of two key ingredients. First, a relationship between the tracking error and the input signal in a high-order CNC servo system is established. As a consequence, the tracking error constraint is reduced to a constraint on the kinematic quantities. Second, a novel method is introduced to relax the nonlinear constraints on kinematic quantities to linear ones. Experimental results are used to validate the proposed method.