直线电机驱动的H型气浮导轨运动平台

建立了双边直线电机驱动的H型气浮精密定位平台,对该精密定位系统的气浮导轨设计方法和双边直线电机同步运动控制等关键技术进行了研究。利用有限元法设计了气浮导轨,分析了气膜压力场的分布情况,采用预加载技术提高气浮导轨的承载能力和刚度等性能。静态特性实验表明,开发的定位平台气浮导轨具有较高的承载能力和刚度,X、Y导轨的竖直方向静刚度为276.9 N/μm和333.3 N/μm。设计了基于同步速度偏差的改进型并联结构同步控制器,采用模糊控制实现PID参数的自适应在线整定。运动实验表明,改进的控制器具有较高的同步控制精度,速度同步精度比一般同步控制提高了3倍多,适合于具有强机械耦合的多电机同步运动控制。H型直线电机气浮定位平台具有承载能力强、精度高的优点,可以用于光刻机和光学检测等精密工程领域。     

直线电机气浮精密平台的设计与控制

高精度综合测量仪在工作中要求达到亚微米级的运动精度,为此建立了X Z直线电机气浮精密运动平台,对气浮导轨设计、直线电机控制等关键技术进行了研究.采用有限元设计法设计了气浮导轨,实验结果表明,采用该方法设计的气浮导轨具有较高的承载能力和刚度.提出一种改进的PID控制策略,从而改善直线电机运动平台的抗干扰能力,并使其获得较高的稳态位置精度.实验结果显示,在采用这种控制方法后,直线电机气浮精密平台的定位精度可达到0.5μm.     

精密高刚度二维气浮工作台的设计与分析

目前精密二维气浮工作台的研究,存在着二维气浮工作台的刚度和承载力较小的问题,设计了一种以精密方箱为基准的精密高刚度二维气浮工作台。该气浮工作台采用整体式气浮导轨副设计,全部构件以精密方箱为位置基准,用精密方箱自身的高平面度、平行度和垂直度来保证X轴和Y轴导轨的运行直线精度和系统刚度,并且工作台采用直线电机驱动,消除了传统机械传递带来的误差。该实验台具有机械精度高、运动直线度高、系统刚度大、安装维护容易等特点,能在精密加工、精密测量领域中广泛使用。     

可拆卸式气浮导轨滑架组件的设计与分析

设计了一种可拆卸式整体气浮导轨组件结构,该气浮导轨滑架采用框架组合结构,可更换多种型号及不同数量的气浮轴承,实现对称和非对称全封闭结构布置。研究了气浮轴承安装位置对平台性能的影响。研究表明:所设计的滑架定位装置能够保证在更换气浮轴承时滑架与气浮导轨的相对位置保持不变,定位装置结构简单、操作方便,对进一步提高气浮导轨对整个精密平台的性能具有重要的指导和借鉴意义。     

气浮导轨性能测试实验台设计与分析

在超精密气浮定位平台研究工作中,对静压空气轴承的安装位置对系统影响的研究相对较少,文中介绍了一种新型机械结构的气浮导轨性能测试实验台,实验台导轨滑架采用焊接框架组合结构,实现不同类型气浮轴承的更换及不同数量的气浮轴承的安装,形成不同结构布局的气浮导轨,能够满足多种气浮导轨的实验研究,提高了气浮导轨实验台的利用率和使用范围。此实验台具有机械精度高、系统刚度大、结构稳定性好,安装使用方便等特点。     

矩形闭式静压气浮导轨结构设计计算与仿真分析

在科技高速发展的今天,高速高精密技术已成为装备制造业的一个发展方向,静压气浮导轨以高精度、无摩擦、温升小、寿命长等优点满足高速和高精密技术的要求,从而引起广泛的关注和研究。本文以矩形闭式静压气浮导轨为研究对象,通过运用流体力学、气体润滑技术和空气静压轴承设计技术等知识,对其进行了合理的设计计算及反复的验证计算。通过仿真分析软件,对其进行了仿真分析,并验证了其设计的合理性。     

高精密微细切削加工机床的研制

微细切削技术的发展离不开微小型化机床设计和制造技术的发展,然而微细切削加工的高精度对微细切削机床的性能和设计提出了更高的要求。因此,针对微细切削机床设计和研制的特点,自主研发了一台微小型切削加工机床,该机床可应用于微细车削、刨削、飞切等加工方式。其设计理念是,利用大理石气浮导轨结合精密直线电机技术,提高机床的精度和加工稳定性。     

光学玻璃专用平面磨床工作台静压导轨设计

光学玻璃专用平面磨床是应用于激光技术、光电通讯、航空航天以及国防工业等领域大尺寸光学玻璃精密加工的专用机床。工作台所在轴的运动是加工辅助运动,其运动精度是影响加工精度的一个重要因素,通过创新设计确定了工作台与床身之间结构为直线电机驱动的双层静压导轨设计方案,力封闭直线电机驱动静压导轨和结构封闭的工作台闭式静压导轨双层结构之间采用弹性连接,有效地避开了直线电机驱动过程中电磁力等因素对工作台运动精度的影响,确保了光学玻璃专用平面磨床的加工精度。     

精密双层气浮直线电机动力学响应分析

高分辨率步进扫描投影光刻机中的精密双层气浮直线电机采用气浮轴承支撑,实现亚微米级定位的高速高精运动。考虑其气固耦合特性以及对运动精度产生的影响,通过有限元的方法建立了精密双层气浮直线电机的有限元模型。在该模型的基础上,应用模态叠加法分析了该系统在各种条件下的动力学响应,得到了在X、Y、Z三个方向的加速度响应曲线;同时,借助实验模态方法,验证了该系统动态响应,从而得到了该系统的谐振频率。仿真计算结果和模态实验结果的偏差小于10％,证明了该模型是正确有效的,为下一步的动态优化和控制设计打下基础。     

二维运动平台气浮静压导轨承载性能计算与研究

为了进一步探索和研究气浮静压润滑支承机理及气浮静压导轨承载性能,提出并研制了一种具有气浮静压润滑支承的精密二维运动平台。结合气浮静压导轨的物理模型建立了其笛卡儿坐标系下的控制方程,采用有限差分方法和流量平衡原理对其控制方程进行了离散差分推导,运用超松弛迭代以及二分快速寻找收敛区间法对其承载性能进行数值计算并开展了实验研究。结果表明：气浮静压导轨承载性能受节流器类型的影响比较显著,多节流孔节流器的承载性能明显优于单节流孔节流器;供气压力对气浮静压导轨承载性能影响显著,供气压力越高其承载性能越强;同等条件下气浮静压导轨组合形式承载性能均优于单独形式承载性能;气浮静压导轨的承载性能实验测试结果和数值计算结果具有较好的一致性,验证了数值计算的有效性。相关研究对推动和促进气浮静压轴承和导轨在精密运动机构和测量设备的研究和工程应用具有较好的借鉴和指导意义。     

A dual-stage control system for high-speed, ultra-precise linear motion

Modern manufacturing equipment often requires high-speed and ultra-precise linear motion. For implementing such motion, a coarse–fine dual stage is effective because the coarse stage has a low bandwidth with a large workspace, and in contrast, the fine stage has a high bandwidth with a small stroke. This paper presents the implementation of an air-bearing, dual-stage system and its control strategy. A closed-loop feedback in an absolute space is used to realize coarse–fine control. The fine stage is driven by a voice coil motor that tracks the designed trajectory, while the coarse stage is driven by permanent-magnet linear synchronous motor that tracks the trajectory of the fine stage to prevent its motion saturation. Also analyzed are the coupled dynamics of the air-bearing dual stage driven by a direct-drive motor. Identification and robust control design for the fine stage are introduced in detail. Method tests for the single fine stage are performed, and the results demonstrate that ultra-precision control can be realized for the fine stage. Next, experiments are presented with the dual stage using different loads. Experimental results show that our control strategy can achieve high-speed, ultra-precision linear motion through the dual stage with a satisfactory performance.     

Reducing the Radial Error Motion of an Aerostatic Journal Bearing to a Nanometre Level: Theoretical Modelling

Ultra-precision air bearings could enable novel and more accurate precision applications. In this paper we report on the design of an ultra-precision air-bearing system, intended to reduce the radial error motion, i.e. the deviation from perfectly centric motion, to a nanometre level (i.e.<10 nm). To this end, the influence of several manufacturing errors, bearing parameters and feeding geometries is analysed on the radial error motion of an aerostatic journal bearing. This finally leads to the formulation of several design guidelines. On this basis, a numerical gas film model is developed and validated. Increasing the number of feedholes proves to be a promising solution as it results in an evenly distributed air film. The latter is confirmed by the fact that the radial error motion of an aerostatic journal bearing with a porous ring feeding geometry, which can be seen as a limiting case of infinite number of feedholes, is only 1 nm.     

基于电流变阻尼超精密气浮工作台研究

为解决直线气浮系统抗干扰能力较差等问题,针对已开发的超精密直线气浮工作台,设计了电流变剪切模式阻尼器;基于屈服前后平滑过渡的Eyring连续本构模型通过辨识得出电流变剪切阻尼器类稳态模型;从仿真和实验研究了电流变阻尼及高电场强度对直线气浮工作台模态的影响,实验模态结果验证了仿真方法的有效性,同时证实设计的电流变阻尼器及电场强度的提高不会造成模态频率的下降,只会引起阻尼比的大幅度提高,甚至减少模态阶数。     

DYNAMIC CHARACTERISTIC ANALYSIS OF PRECISE LONG STROKE LINEAR MOTOR WITH AIR-BEARING IN OPTICAL LITHOGRAPHY

Dynamic characteristic is presented by identifying the model and the dynamic parameters of a precise long stroke linear motor （PLSLM） with the air-bearing in optical lithography. The PLSLM is supported by air-bearing on the stator, and is driven by on-board two large linear motors in a cross-configuration. Firstly, a model of the PLSLM is established by finite element method （FEM）. Secondly, based on the model, the natural frequencies and model shapes are discusse＆ And the contribution of each active mode is evaluated by computing the modal participation factors （MPF）, which indicates the major vibration direction. Furthermore, by the experimental modal analysis, the experimental results are in agreement with simulation results, which it is sure that the FEM is reasonable. What＇s more, comparing with the effects on the frequency due to the air-bearing stiffness, the relations of the natural frequencies with the air-bearing stiffness are found. It is found that the frequency response curve is fluctuant with the air-bearing stiffness in each direction. Finally, it is conclusion that the natural frequency of the PLSLM is largely affected by the air-bearing stiffness variety. This research is contributed to the dynamic characteristics resulted from the air-beating stiffness. Further work will include better optimization on the dynamic parameter in the controller design through the control algorithm for the precise long stroke motor.     

基于电流变阻尼超精密气浮工作台建模及控制研究

随超精密装备加工精度和生产率的不断提高,直线气浮系统得到广泛重视和研究。为解决直线气浮系统抗干扰能力较差等问题,针对已开发的超精密直线气浮工作台,设计了电流变剪切模式阻尼器;建立了气浮工作台整体模型并基于屈服前后平滑过渡的Eyring连续本构模型通过辨识得出电流变剪切阻尼器类稳态模型;分别对零电场线性及高电场非线性电流变阻尼2种情况下的气浮工作台应用误差积分LQR控制器;为达到综合最优,进一步提出开关及滑模控制器,实验证实这2种控制策略均能同时提高系统的响应速度、减少建立时间,降低跟踪误差及纹波。     

Development of magnetically preloaded air bearings for a linear slide: active compensation of three degrees of freedom motion errors

This article describes a linear air-bearing stage that uses active control to compensate for its motion errors. The active control is based on preloads generated by magnetic actuators, which were designed to generate nominal preloads for the air bearings using permanent magnets to maintain the desired stiffness while changing the air-bearing clearance by varying the magnetic flux generated by the current in electromagnetic coils. A single-axis linear stage with a linear motor and 240 mm of travel range was built to verify this design concept and used to test its performance. The motion of the table in three directions was controlled with four magnetic actuators driven by current amplifiers and a DSP (Digital Signal Processor)-based digital controller. The motion errors were measured using a laser interferometer combined with a two-probe method, and had 0.085 microm of repeatability for the straightness error. As a result of feed-forward active compensation, the errors were reduced from 1.09 to 0.11 microm for the vertical motion, from 9.42 to 0.18 arcsec for the pitch motion, and from 2.42 to 0.18 arcsec for the roll motion.     

超精密非球面镜面计算机辅助设计与应用

非球面镜面加工技术的研究已经成为先进制造技术的核心问题之一,相关的超精密装备制造关键技术除了机床本体,最重要的是系统控制软件及应用软件的开发,这是制约自主产权的超精密加工装备技术发展的瓶颈问题之一。结合作者在日本从事NEDO项目合作的实际经验,深入细致地阐述了超精密非球面镜面计算机辅助设计(CAD)系统的算法原理、系统结构及系统实现,并通过实际的光学镜面设计实例,介绍SGT-CAM软件系统具体开发及应用,为超精密非球面镜面的计算机辅助加工打下了基础。该系统已经成功地应用于自行开发的小型超精密镜面加工机SGT100上,形状误差小于100纳米,表面粗糙度小于5纳米,得到有关专家的充分肯定。     

折叠式柔性结构振动主动控制仿真实验系统

为了对复杂柔性结构的振动主动控制进行实验研究，针对折叠式航天柔性结构的特点和运行环境，设计并建立了基于单轴气浮机动台的折叠式柔性结构振动主动控制的仿真实验系统。实验系统不但能够模拟柔性航天结构的运行环境。还能对由于航天飞行器的机动和折叠结构的展开而引起的振动进行模拟，讨论了该实验系统的设计方案，介绍了系统的各个组成部分，初步实验结果表明，系统工作稳定可靠，振动控制效果明显。     

Micro/nano sculpturing of hardened steel by controlling vibration amplitude in elliptical vibration cutting

A new ultra-precision sculpturing method in micro/nano scale for difficult-to-cut materials is proposed in the present research. Elliptical vibration cutting technology is well-known for its excellent performance in achieving ultra-precision machining of steel materials with single crystal diamond tools. Elliptical vibration locus is generally controlled and held to a constant in practice. On the contrary, the proposed method utilizes the variations of the elliptical vibration locus in a positive manner. Depth of cut can be actively controlled in elliptical vibration cutting by controlling vibration amplitude in the thrust direction. By utilizing this as a fast tool servo function in elliptical vibration cutting, high performance micro/nano sculpturing can be attained without using conventional fast tool servo technology. A high-speed amplitude control system is developed for elliptical vibration, with a bandwidth of more than 300 Hz, where the vibration amplitude can be controlled within 4 μm_p-p. The developed control system is applied to sculpturing ultra-precision nano textured grooves on hardened steel with single crystal diamond tools. It is confirmed that the textured grooves have the desired shapes, and their profiles agree well with the vibration amplitude commands input to the control system. Further, a high performance micro/nano sculpturing system for plane surfaces is developed, where the vibration amplitude is controlled in synchronization with the planing motion of an ultra-precision machine tool. Nano sculpturing experiments on hardened steel, carried out by the developed system, are reported, as well as consequent picture images and a variety of dimple patterns that were formed successfully on the hardened steel as nano-scale sculptures.     

零差移频式干涉图形相位锁定系统的超精密控制

利用全息曝光法制造大口径全息平面光栅时,常引入零差移频式干涉图形相位锁定系统来提高全息曝光质量。本文针对直接影响最终干涉曝光精度的系统控制精度开展研究。首先,介绍了新型的零差移频式干涉图形锁定系统的原理和结构,在系统理论建模及模型辨识的基础上,针对非线性系统模型进行了高阶线性化拟合,并结合系统振动测试实验结果,设计了系统控制器。然后,对设计的控制器进行了实际控制调试,实现了系统的超精密控制。最后,针对系统控制误差纹波,采用频域分析方法揭示了影响系统控制精度的主要因素,提出了未来提升系统控制精度的方法。测试结果显示:系统相位锁定控制精度可达±0.046 1rad(3σ)且以高频误差纹波形式呈现。分析了高频误差纹波的成因,指出受系统噪声、延迟、控制器参数等因素限制,控制器很难完全抑制频段跨度大而连续的高频微振动引起的干涉图形相位漂移。