直接磁悬浮永磁直线电动机无摩擦进给的研究

提出采用直接磁悬浮永磁直线电动机来消除数控机床进给系统的摩擦阻力实现无摩擦进给,对直接磁悬浮永磁直线电动机的结构和磁悬浮原理进行了论述,建立了磁悬浮永磁直线电动机的磁场分层模型,在此基础上,从磁场能量出发通过虚位移法推导出磁场和电磁力的表达式.利用Ansoft Maxwell 2D瞬态电磁场计算软件,对直接磁悬浮永磁直线电动机的空载磁场,以及负载运行时的气隙磁密和电磁力进行仿真研究.结果表明,采用直接磁悬浮永磁直线同步电动机实现数控机床无摩擦进给是可行的.     

磁悬浮永磁直线电动机及其控制系统研究

根据磁悬浮永磁直线电动机的特殊结构与运行机理,给出了电动机电磁推力和悬浮力的数学模型。建立了磁悬浮永磁直线电动机的有限元计算模型,对气隙磁密、电磁推力和悬浮力进行了有限元计算,并对气隙磁密作了谐波分析。设计了磁悬浮永磁直线电动机的研究样机,制作了磁悬浮子系统和进给伺服子系统,对系统进行实验研究,获得了磁悬浮子系统和进给子系统运行的实验结果。实验研究结果表明,该磁悬浮永磁直线电动机可实现直接驱动与无摩擦运行。     

可控励磁磁悬浮进给平台电磁特性的有限元分析

设计一种可控励磁直线同步电动机磁悬浮进给平台,平台与直线同步电动机动子固定相连,直线同步电动机同时实现平台的进给与悬浮。可控励磁磁悬浮进给平台的电动机定子为直流励磁,磁极既是励磁磁极也是平台的悬浮磁极,磁极与动子铁心间的法向力为平台的悬浮力,调节励磁电流改变平台的悬浮力;电枢在磁场中受到的切向力为驱动平台的电磁推力,调节电枢电流以调节平台的电磁推力。为了研究可控励磁直线同步电动机磁悬浮进给平台的电磁特性,建立了该平台的数学模型和运动方程,并在数学模型的基础之上对电磁推力与悬浮力进行有限元计算。电磁推力的解析计算结果与有限元分析结果相比较,最大相对误差为8.73%,悬浮力的解析计算结果与有限元分析的结果相比较,最大相对误差为19.15%。计算结果表明可控励磁磁悬浮进给平台运行的可行性。     

新型混合励磁磁悬浮进给平台的解耦控制研究

针对数控机床进给平台存在的摩擦问题,提出一种基于混合励磁直线同步电机的新型磁悬浮进给平台的结构及运行原理。该磁悬浮进给平台推进系统和悬浮系统共用一个气隙磁场,电磁推力和法向力存在磁力耦合现象。对混合励磁直线同步电机的电磁推力和法向力进行了数值分析及有限元验证;建立了系统相应的状态方程和输出方程,并对系统进行了解耦控制。仿真结果证明:采用输入变换结合状态反馈可以实现电磁推力和法向力的完全解耦,有利于提高进给平台运动的平稳性及定位精度。     

数控机床用直线电动机的选型及分析

结合高速切削需求,详细阐述了高速数控机床选用永磁直线同步电动机(PMLSM)的计算和校验过程,并分析了选型过程中应该注意的事项.直线电动机不经过任何机械转换装置直接产生直线运动,提高了驱动系统的进给速度、加速度、刚度和定位精度,而且结构简单,噪声低,无直接机械磨损,故其在高速度、高精度数控机床进给驱动系统中的应用日益广泛.     

磁悬浮进给机构设计

设计了一种集磁悬浮技术和线性驱动技术为一体的精密磁悬浮进给机构。这种机构采用直线同步电动机对悬浮平台进给机构提供驱动力。实现了进给机构在水平和垂直两方向的无接触支撑和导向，具有响应快速、刚度高以及定位精确的特点，能够满足微电子设备高精度、高效率和超洁净加工的需要。文章还对磁悬浮力和直线电动机推力进行了分析计算。     

数控机床用直线电动机的选型及分析

结合高速切削需求，详细阐述了高速数控机床选用永磁直线同步电动机（PMLSM）的计算和校验过程，并分析了选型过程中应该注意的事项。直线电动机不经过任何机械转换装置直接产生直线运动，提高了驱动系统的进给速度、加速度、刚度和定位精度，而且结构简单，噪声低，无直接机械磨损，故其在高速度、高精度数控机床进给驱动系统中的应用日益广泛。     

高精数控机床永磁直线进给工作台的力学性能分析

高精数控机床永磁直线进给系统的力学特性严重影响机床性能,为研究直线进给系统的力学性能,将永磁直线同步电动机动子与工作台作为一体化结构,利用有限元法对在直线电动机法向电磁力作用下的进给工作台分别进行静力学和动力学分析,并对样机进行了振动测量。结果表明:永磁直线同步电机动子与工作台作为一体结构的变形比电机动子单一结构的变形大,固有频率也有所降低,更易产生共振。精密机床的直线进给系统作为机电一体化结构,应将电机和机械结构作为整体进行分析研究才有实际意义。     

圆筒型直线步进电动机在机床中的应用与推力计算

在分析平板型直线电动机在机床进给系统中的配置结构与存在问题的基础上,结合圆筒型直线电动机的特点,提出了将圆筒型直线步进电动机用于机床进给系统中的新方案.并开展了对圆筒型直线步进电动机的推力计算方法的研究,建立了圆筒型直线步进电动机电磁计算的有限元模型,得出了电动机力移曲线,模型试验证明了理论计算方法的可靠性.估算了电动机的平均推力,为进一步研究该电动机性能及在机床中的应用提供了有效的方法.     

高档数控机床中永磁直线同步电机驱动系统关键技术分析

直线电机驱动系统具有高推力、高速、高精度、平滑进给运动等特性,在高档数控机床上的应用越来越多。极大地提高了高档数控机床进给系统的快速反应能力和运动精度。分析了永磁直线同步电机在高档数控机床应用中的一些关键技术问题。     

直线电机及其在高速精密机床上的应用

直线电机直接驱动方式是高速精密机床进给系统的一种理想驱动方式。介绍直线电机的工作原理,高速精密加工对机床进给系统的要求,以及直线电机在高速精密机床上应用所具备的优点与存在的问题。     

Levitation control of an improved modular bearingless switched reluctance motor

In order to reduce coupling between torque and suspending force in conventional bearingless switched reluctance motor (BLSRM), one 12/12 hybrid-stator-pole structure BLSRM was investigated. In this structure, motor consists of two single phase motor. Biased flux is provided by axial permanent magnet, which is installed between two motor in axial direction. However, axial permanent magnet occupies axial space, which results in increased axial length and decreased critical speed. Therefore, an improved modular BLSRM is proposed in this paper. In order to reduce axial space and improve critical speed, permanent magnet is designed to install in stator yoke. To realize steady levitation during rotor rotating, one simple levitation control strategy is put forward, which is benefitted from natural decoupling between torque and suspending force. In addition, digital control system including torque and suspending force is designed by means of TMS320F28335 and experimental platform is established. Finally, the improved BLSRM can be steadily levitated in the static and rotating conditions by experimental results.     

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.     

开放式数控磨削加工系统中直线电机的应用研究

对高速、超精密加工来说，传统的进给系统已难以满足要求。近年来，直线电机作为一种新型直接驱动进给装置得到广泛应用。简单介绍了直线电机的基本原理，并利用开放式控制器PMAC(Programmable Muhi—Axis Controller)集成了一套磨削加工系统，在利用PID 前馈控制法对直线电机控制性能研究的基础上，实现了直线电机的微量往复进给运动，为推动直线电机及PMAC在高速高精度数控机床中的应用打下了基础。     

基于PMAC-PC的精密加工系统的设计与实现

介绍了应用PMAC(Programmable Multi—Axis Controller)-PC作为核心控制器，设计集成了一套新型精密加工系统。研究了直线电机的伺服控制技术和电主轴的设计制造等问题。结合直线电机的微量往复进给运动和电主轴的高速性能，实现了对椭圆零件的高速精密加工。为推动高速高精度数控机床制造技术的发展打下基础。     

Control of linear motor machine tool feed drives for end milling: Robust MIMO approach

Linear motors become promising for use as high speed, high accuracy machine tool feed drives. The cutting force in the machining process are directly reflected to the linear motor due to no gearing mechanism. To achieve highly accurate machining, the controller for the linear motor system should be designed to compensate for the cutting force.     

直线电动机在非圆截面零件精密加工中的应用研究

对具有种类多、高精度和高频响伺服控制要求的非圆截面零件加工来说,传统进给系统已难以满足要求。近年来,直线电动机作为一种新型伺服驱动进给装置,得到广泛应用。简单介绍了直线电动机在国内、外的应用现状,综述了直线电动机的基本原理及特点。利用PMAC(Programmable multi-axis controller)时基控制法,通过椭圆形等典型非圆零件表面精密加工试验,研究了基于PMAC的直线电动机的伺服控制技术和防磁散热等问题。为推动直线电动机在高速高精度数控机床中的应用打下基础。     

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%.     

Linear motor for ejector mechanism

Ejector mechanism actuators in electric injection moulding machines require large thrust and low operating rate. Although the ordinary linear synchronous motor (LSM) is unfit for this machine, the linear motor presented in this paper is suitable for this use as it is compact in size and more cost effective compared to LSM.This paper contains the new linear motor that can generate large thrusts for a short time: its mechanical design, simulated flux profile and experimental results of motor size and thrust output relationship are presented. The described linear motor has an approximate volume of 250 mm×250 mm×250 mm and generates a maximum thrust of about 20 kN at a current of 250 A. This revised version was published online in October 2004 with a correction to the issue number.