高速数控机床三种进给系统的分析与评价

本文在明确了高速加工对机床进给系统的要求的基础上，讨论和比较分析了滚珠丝杠、直线电机和并联虚拟轴机构等三种高速进给方式的性能、特点、存在问题及其解决办法，指出了它们各自的适用范围和应用前景。     

数控机床进给伺服系统故障仿真

进给伺服系统是整个数控装置的重要组成部分.由于它出现故障的机会相对多一些,而且进给伺服系统故障所造成后果也比较严重,轻则停机,影响加工精度,重则会严重损坏机床.通过分析数控机床进给伺服系统各部分的传递函数,建立了数控机床进给伺服系统的数学模型,并利用Simulink/MATLA日仿真软件建立了进给伺服系统的仿真模型.后利用此仿真模型·对进给伺服系统部分典型故障案例进行了仿真研究和故障分析.仿真结果对数控机床位置伺服系统故障机理进行研究,利用Matlab软件进行仿真模拟是一条有效的途径.     

QYLC10重型数控机床进给驱动系统设计与仿真

根据机械动力学原理,考虑进给丝杠轴的弹性,建立QYLC10重型数控机床进给驱动系统的数学模型,分析进给轴的刚度对系统性能的影响.基于MATLAB软件利用阿克曼极点配置法设计系统的状态反馈控制器,建立进给驱动系统的状态空间仿真模型,对极点配置的可行性进行仿真分析.研究结果表明:进给驱动系统的刚度越低,系统的稳定性越差;利用阿克曼极点配置法可以把进给系统的闭环极点设置在任何期望的位置上,有效克服了进给系统刚度不足对稳定性的不利影响,使系统获得更理想的动态性能.所进行的研究对于其他高阶系统或多输入/多输出系统的控制器设计具有参考价值.     

Optimal machine tool spindle drive gearbox design

Many machine tools are equipped with a motor-gearbox to extend the constant power range of the machine tool spindle drive motor at low speeds. Currently, in the latest spindle drive motor technology, the gearboxes are integrated in-line between the water-cooled motor and the spindle inside the machine tool’s ram. The functionality of a spindle gearbox depends directly upon its constructional solution, and on the kinetic energy corresponding to this solution. In this work, spindle gearboxes are optimized taking this design factor into account. In the authors’ opinion, the results could be of great interest for spindle drive gearbox manufacturers.     

An integrated prediction model for the dynamics of machine tool spindles

ABSTRACT

The predictility of dynamics of the machine tool spindles is essential for machining precision. During machining, the machine tool components and the cutting process interact with each other. Accordingly, it is necessary to take the process-machine interaction effects into account in order to predict the spindle's dynamics accurately. This paper presents an integrated model for the prediction of a spindle's dynamics. The model synthesizes the interactive influence between machine dynamics and forces in grinding process. The thermo-mechanical model of the spindle with angular contact ball bearings was built by using the finite-element method. The analytical model was used to calculate the process forces. A coupled simulation was adopted to accomplish the interactive process between the two models. Basing on the integrated model, the bearing stiffness, the natrual frequency, the spindle tip stiffness and deformations of a grinder's spindle were investigated. The prediction of the deformation fluctuations at the spindle tip due to process-machine interaction was also achieved.     

机床曲线进给系统的三维建模和动态仿真

提出用四杆机构代替传统机床的导轨，利用四杆机构的连杆曲线实现机床的无导轨曲线进给，用于各种异型曲面的加工。基于UG对四杆机构进行了三维设计，基于ADAMS对四杆机构进行了动态仿真，仿真结果表明了杆长的制造误差与走刀误差之间的关系，为机床曲线进给系统的虚拟设计与虚拟制造提供依据。     

机床的进给驱动(下)

提出了设计高端机床进给驱动的若干原则.分析了滑动和滚动导轨的结构形式及其优缺点.讨论了不同直线进给和圆周进给的结构形式及其发展趋势.最后对保证进给运动精度的测量传感系统作了全面的介绍.     

自动制袋包装机驱动进给结构优化设计

基于电工电器产品柔性生产线包装设备研究,对结构特点和作用进行了分析;优化设计制袋包装机驱动进给结构,实现在线自动传输产品、自动拉膜制袋、自动包装封口.实践表明,使用优化设计方法改造传统设备结构的可行性、有效性.     

数控机床中分频段调压的步进电机驱动设计

本文介绍数控机床中应用步进电机的基本概念、常用的几种驱动方式及步进电机的工作原理,分析调频调压原理,采用单片机实现分频段调压,达到消减低频振荡的目的.硬件实现万法简单、系统可靠性强.     

Computer simulation machining a 3D free surface by using a 3-RPRU parallel machine tool

A novel computer aided geometric approach is proposed to machine a 3D free surface by adopting a 3-RPRU parallel machine tool. Based on the geometry constraint and dimension-driving technique, a 3-RPRU parallel simulation mechanism is first created. Next, a 3D free surface and a guiding plane of tool path are constituted. Finally, the 3-RPRU parallel simulation mechanism, the 3D free surface, and the guiding plane of the tool path are combined together, and a novel 3-RPRU simulation parallel machine tool is created for machining a 3D free surface. In the light of two specified tool paths, the extension of the three driving rods and the position of the moving platform are solved and visualized dynamically. Based on the computer simulation results, some analytic formulas are derived to solve the extension of driving rods of the 3-RPRU parallel machine tool in a reverse solving process. From the simulation and analytic results, it is proven that the computer simulation machine tool approach is equivalent to the analytic approach to machine 3D free surfaces. The computer simulation machine tool approach is straightforward without compiling computer programs, and is also advantageous from the viewpoint of accuracy and repeatability. This project is supported by NSFC 50575198.     

VMC1300加工中心伺服进给系统的设计

介绍了VMC1300立式加工中心伺服进给系统的一种新的综合设计方法,包括滚珠丝杆副及其支承的选取、伺服电动机的选取、联轴器的选取.并着重对电动机的转矩、转动惯量及加速能力进行了匹配校核,对机械传动装置刚度变化及弹性系统刚度变化引起的定位误差进行了验算.     

Milling tool wear diagnosis by feed motor current signal using an artificial neural network

In this paper, a Multi-layer perceptron (MLP) neural network was used to predict tool wear in face milling. For this purpose, a series of experiments was conducted using a milling machine on a CK45 work piece. Tool wear was measured by an optical microscope. To improve the accuracy and reliability of the monitoring system, tool wear state was classified into five groups, namely, no wear, slight wear, normal wear, severe wear and broken tool. Experiments were conducted with the aforementioned tool wear states, and different machining conditions and data were extracted. An increase in current amplitude was observed as the tool wear increased. Furthermore, effects of parameters such as tool wear, feed, and cut depth on motor current consumption were analyzed. Considering the complexity of the wear state classification, a multi-layer neural network was used. The root mean square of motor current, feed, cut depth, and tool rpm were chosen as the input and amount of flank wear as the output of MLP. Results showed good performance of the designed tool wear monitoring system.     

3-TPT并联机床动力学仿真

首先应用拉格朗日法建立并联机床的动力学模型,由拉格朗日方程展开后得到动力学方程的标准形式;其次结合一个实例,应用Matlab仿真软件对3-TPT并联机器人各杆的杆长与时间的变化及各杆驱动力与时间的变化进行了仿真;最后经分析可知驱动力呈周期性变化,且在加速和减速阶段有突变.所以该并联机床动平台在匀速阶段运动平稳,而在加速和减速阶段存在振动.     

Development of a machine tool selection system using AHP

The selection of appropriate machines is one of the most critical decisions in the design and development of an efficient production environment. In this study, we propose a decision support system for machine tool selection using an effective algorithm, the analytic hierarchy process. In the selection process, we first consider qualitative decision criteria that are related to the machine properties. Reliability and precision analyses may be included in the detailed evaluation procedure. Furthermore, the decision-maker may take into account the economical considerations through cost analysis. In addition, the robustness of the selection procedure may be evaluated using sensitivity analysis. An illustrative example of machine tool selection using the proposed methodology and the software implementation are provided.     

机床设备选择模型建立及综合评价

应用模糊综合评价理论建立数学模型来评价数控机床,使这种评价科学,实用。     

对当前机床工具行业形势的分析

2002年机床工具行业产、销两旺。据国家统计局资料,1～11月份机床工具行业八个制造业完成工业总产值684.8亿元,同比增长16.6％;产品销售收入637亿元,同比增长17.2％,预计全年产、销总额分别可达750亿元和700亿元左右。出口平稳增     

模糊自适应PID在数控进给伺服系统的应用

数控机床的进给伺服控制是复杂的机电耦合系统,因其存在参数时变、负载扰动以及电机的非线性等缺点,很难为其建立准确的模型.模糊FIJzzy控制具有无需建立被控对象的数学模型、鲁棒性好等优点但稳态精度差,将模糊控制和PID控制相结合,设计了模糊自适应PID控制器,并将此应用于数控伺服系统的控制中,该控制器具有较完善的控制性能.仿真实验的结果表明,采用该模糊自适应PID控制器具有较高的稳定精度,较强的鲁棒性.