数控机床伺服进给系统无传感器检测技术

提出一种基于光栅尺与编码器信号的机床伺服进给系统定位精度检测方法;深入研究电流、扭矩、润滑特性之间关系,获取伺服电动机电流并据此对机床润滑状态进行分析和监测.在全闭环和半闭环条件下进行单轴直线和两轴联动圆测试,实验表明位置、瞬时速度等光栅尺、编码器信息可以用于机床伺服进给系统精度评定和控制特性评估;进行了不同进给速度下的恒速、润滑特性测试,试验分析表明机床润滑特性符合Stribeck摩擦效应,能够实现对机床润滑和运行状态进行监测.     

基于内置传感器的大型数控机床状态监测技术

提出一种基于光栅尺、编码器、伺服进给电机电流(转矩)等内置传感器的机床状态监测系统,深入研究转矩、位置、润滑特性等内置传感器测试原理,就开放式和商业数控系统给出不同采集机床状态信息的策略;并进行多种工况下的恒速、润滑特性测试,试验分析表明电机输出转矩(电流)、位置、瞬时速度、瞬时加速度等内置传感器信息被用于机械传动部件故障诊断和伺服控制特性评估的可行性和有效性,从而为大型数控机床状态在线监测和故障快速溯源,提供技术支撑.     

基于无传感器信息的数控机床伺服进给系统性能评估研究

无传感器测试是相对于加速度、切削力、声发射、球杆仪等外置传感器信息采集、分析的一种策略,即深入研究数控机床伺服控制系统内置的电机编码器、光栅尺、电机伺服驱动器霍尔电流传感器等测试元件所提供的信息,通过合理规划测试路径进行激励,并结合基于先进的信号数据处理方法,对伺服进给系统动态性能进行评估。     

基于动态特性的数控铣削参数自适应在线优化

为避免切削力突变对机床加工稳定性带来的影响,针对数控加工复杂非线性的特点,提出了基于动态特性的模糊自适应控制策略,实时监测和提取主轴电机电流而间接获得切削力,基于数控加工系统动态特性得到电流与进给速度间实时变化关系,据此对基于经验的控制规则进行优化,对影响切削力的进给速度在线自适应优化,以电流作为反馈量来控制切削力并保持切削过程稳定。实验结果表明,该方法可以更快地使切削力调整到既定值,提高加工效率和稳定性,发挥机床最大功效。     

数控机床伺服进给系统动态性能测试平台开发

首先分析了数控机床伺服进给系统动态性能测试功能需求和方案,之后给出了基于正弦波编码器的位置信号算法和基于矢量控制原理的iq算法,描述了基于Labview和NI数据采集设备的软硬件平台搭建,实现了数控机床伺服进给系统位置、速度和电流iq的同步测试,最后给出了测试平台的实际应用效果。     

基于无心车床主轴电机电流的钛合金切削力经验公式的实验研究

针对目前无心车床钛合金切削力计算公式推导的困难性和复杂性,通过测量主电机电流的实验方法来探索难加工材料钛合金的切削规律,打破了传统的测量切削力的实验平台,解决了传统方法中实验平台搭建过程的难题。同时以空心主轴电机电流为主要实验数据,结合切削深度以及进给速度等实验数据,在SPSS软件中进行线性回归分析,拟合出了切削力经验公式,验证了该经验公式在实际的加工中的指导意义,为进一步研究钛合金的切削机理奠定了研究基础。     

氧化锆陶瓷侧铣切削力实验研究

在五坐标加工中心上采用硬质合金刀具对氧化锆陶瓷进行了侧铣实验.基于Matlab软件对采集到的切削力信号进行了时域、频域和小波包分析.研究了进给速度、切削宽度、主轴转速的变化对切削力的影响.实验结果表明:切削力随切削宽度的变化而变化,且近似成正比例关系;随进给速度的增加切削力不成比例增大;切削力在主轴转速低于4000 r/min前提下随转速的提高略有减小.     

交流伺服进给系统滑模变结构扰动观测补偿控制

介绍了用于交流伺服进给系统的滑模变结构扰动观测补偿器,解决了当存在解决耦误差和负载扰动时,普通伺服控制算法难以同时抑制负载扰动和高阶把动的问题。分析了电机转矩信号扰动观测补偿器的建模和设计过程,讨论了交流同步电机伺服进给系统的计算机仿真研究结果。     

基于LabVIEW的微进给刀架切削力测试系统的研究

基于LabVIEW的微进给刀架测试系统,包括基于GMM驱动的微进给刀架及其微应变测力系统的设计、信号采集调理电路的设计和基于LabVIEW开发平台的系统软件设计,该系统方便地实现了基于GMM驱动的微进给刀架切削力输出信号的数据采集、分析、处理及存储,为开展微细加工机理研究提供必须的实验手段。     

基于无心车床主轴电动机单元电流的钛合金切削力经验公式的试验研究

针对目前无心车床钛合金切削力计算公式推导的困难性和复杂性,通过测量主电动机电流的试验方法来探索难加工材料钛合金的切削规律,打破了传统的测量切削力的试验平台,解决了传统方法中试验平台搭建过程的难题。同时以空心主轴电动机电流为主要实验数据,结合切削深度以及进给速度等试验数据,在SPSS软件中进行线性回归分析,拟合出了切削力经验公式,验证了该经验公式在实际加工中的指导意义,为进一步研究钛合金的切削机理奠定了研究基础。     

Indirect Cutting Force Measurement Considering Frictional Behaviour in a Machining Centre Using Feed Motor Current

In machine tools, friction exists between the table and the guideways, and in ballscrews. In this paper, feed motor current is measured by a hall effect current sensor. It is used to calculate the motor torque which, in turn, is the frictional torque at steady state. Some frictional phenomena are studied in feed drive systems of a horizontal machining centre, such as the relationship between feedrate and frictional torque, the relationship between frictional torque and table feed position, and the slideway cover effects on frictional torque. Considering all these frictional phenomena, the relationship between the feed force and the feed motor current is obtained. Feed force can be estimated well from the feed motor current considering frictional behaviour. The relationship between the cutting force and the feed motor current is slightly different during up milling and down milling, because y(vertical) directional cutting force changes the frictional force.     

Feed Cutting Force Estimation from the Current Measurement with Hybrid Learning

It is very important to use reliable and inexpensive sensors to obtain useful information about manufacturing processing, such as cutting force, for monitoring automated machining. In this paper, the feed cutting force is measured using an inexpensive current sensor installed on the a.c servo motor of a CNC turning centre. The factors that affect a feed drive system are analysed in detail, and a model of the feed drive system for estimating feed cuttinng force is presented. The feed cutting force is estimated using feed motor current measurement and neuro-fuzzy techniques. Experimental results demonstrate that this medthod can accurately estimate feed cutting force within an error of 5%.     

FANUC 0i系统进给伺服电机的选择

介绍了在FANUC 0i系统的数控机床中,根据负载条件如何选择进给伺服电机的方法。通过计算负载力矩、负载惯量和加速力矩等要素,结合FANUC各伺服电机的相关参数,并以实例说明进给轴应选择的伺服电机型号。     

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.     

重复控制及其在变速非圆车削中的应用

为了提高变速非圆车削中直线伺服单元的跟踪精度和鲁棒性 ,建立了变速非圆车削的进给驱动直线电机、运动控制目标函数、主轴变速、切削力等的数学模型 ,分析了主轴变速精度对直线伺服单元控制的影响。应用重复控制理论设计了适于直线伺服单元的重复控制器 ,给出了详细的设计过程和稳定性分析 ,对控制器的性能进行了仿真分析。结果表明 ,基于重复控制的直线伺服单元能很好地跟踪变速非圆车削中刀具运动的目标值 ,能抑制波动的切削力对跟踪精度的影响。     

Cutting torque and tangential cutting force coefficient identification from spindle motor current

This article presents an enhanced methodology for cutting torque prediction from the spindle motor current, readily available in modern machine tool controllers. This methodology includes the development of the spindle power model which takes into account all mechanical and electrical power losses in a spindle motor for high-speed milling. The predicted cutting torque is further used to identify tangential cutting force coefficients in order to predict accurately the cutting forces and chatter-free regions for milling process planning purposes. The developed model is compared with other studies available in the literature, and it demonstrates significant improvements in terms of the completeness and accuracy achieved. The developed model is also validated experimentally, and the obtained results show good compliance between the predicted and the measured cutting torque. The developed enhanced procedure is very appealing for industrial implementation for cutting torque/force monitoring and tangential cutting force coefficient identification.     

精密冷轧环机工艺动力学模型

采用交流伺服电机和机械驱动进给系统的冷轧环机,其进给伺服控制系统的设计需要一个新的工艺动力学模型。给出了交流永磁同步伺服电机的数学模型,建立了机械传动机构的等效动力学模型,分析了环件冷辗扩的运动学和变形力学条件,得到了整个进给系统的工艺动力学模型。模型表达了伺服电动机电流、转矩、转速与轧制载荷、芯辊进给速度和位置,以及环件几何尺寸之间的动态关系,各变量之间存在非线性和耦合。模型已用于冷轧环工艺控制器的设计。     

伺服力矩马达输出转矩影响因素分析

电液伺服阀作为液压伺服控制元件中的核心元件,能将微弱信号转换为大功率信号,力矩马达作为电液伺服阀的核心元件,其性能直接影响电液伺服阀的性能。为了分析力矩马达输出转矩的影响因素,基于AMESim搭建仿真平台对各个因素进行分析,结果表明,永磁体剩余磁化强度、衔铁中心到衔铁末段距离、气隙处磁极面积和线圈匝数对力矩马达输出转矩影响较大,永磁体的长度以及横截面积和衔铁处于中位时气隙长度对力矩马达输出转矩影响较小,并通过试验验证了其正确性。     

Real-Time Prediction of Workpiece Errors for a CNC Turning Centre, Part 3. Cutting Force Estimation Using Current Sensors

This paper presents a new method for measurement of cutting force using reliable and inexpensive current sensors. The relationship between the various factors which affect the performance of the spindle and feed drive systems are analysed, together with models of the spindle and feed drive system. The tangential (Ft) and axial cutting forces (Fa) are measured, using a neuro-fuzzy technique, with inexpensive current sensors installed on the a.c. servomotors of a CNC turning centre. The normal cutting pressure (Kn) and effective friction coefficient (Kf ) are calculated using the model of the cutting force and the two cutting forces measured by motor current, then the radial cutting force (Fr) can be calculated based on the model of cutting force. Experimental results show that the method can measure tangential, axial and radial cutting forces within errors of 10%, 5% and 25%, respectively, so the need for controlling or monitoring the cutting processes can be met in practice.     

An investigation of the characteristics of the stationary feed motor current in NC machines

The cross-feed directional cutting force acts normal to the machined surface of a workpiece. It is important to estimate and control this force, since it directly affects the machined surface. However, using the current supplied to a stationary motor to predict the cutting state poses difficulties, because of the current's somewhat undesired behaviour. In this paper, a largely empirical approach was used to help resolve this problem. We show that the current's undesired behaviour is related to infinitesimal rotations of the motor. Subsequently, the relationship between the current and the cutting force was identified with an error of less than 15%. The predictions obtained using two machine tools with different characteristics were compared to confirm the validity of the method when investigating the characteristics of the stationary feed motor current.