Design of a control system for a macro-micro dual-drive high acceleration high precision positioning stage for IC packaging

A macro-micro dual-drive positioning system showing good potential for high acceleration and high precision positioning required in IC packaging applications is devised in this paper. The dual-drive positioning stage uses a VCM (voice coil motor) driven macro positioning stage and a PZT piezo-electric driven micro positioning stage. The coupling characteristics of the system are analyzed to produce a control structure with a micro positioning stage that can dynamically compensate for the positioning error produced by the macro positioning stage. Models of the two positioning stages are described. The models cover both the mechanism and the actuator. For the macro positioning stage, friction characteristics are taken into account, and a controller with an LQG (linear-quadratic-Gaussian) control algorithm combining a feed-forward compensation algorithm is derived. A PID controller is used to control the micro positioning stage. Detailed designs are derived for the proposed approach, and the performance is validated by simulation.

Experiments and Simulation of Thermal Behaviors of the Dual-drive Servo Feed System

The machine tool equipped with the dual-drive servo feed system could realize high feed speed as well as sharp precision. Currently, there is no report about the thermal behaviors of the dual-drive machine, and the current research of the thermal characteristics of machines mainly focuses on steady simulation. To explore the influence of thermal characterizations on the precision of a jib boring machine assembled dual-drive feed system, the thermal equilibrium tests and the research on thermal-mechanical transient behaviors are carried out. A laser interferometer, infrared thermography and a temperature-displacement acquisition system are applied to measure the temperature distribution and thermal deformation at different feed speeds. Subsequently, the finite element method （FEM） is used to analyze the transient thermal behaviors of the boring machine. The complex boundary conditions, such as heat sources and convective heat transfer coefficient, are calculated. Finally, transient variances in temperatures and deformations are compared with the measured values, and the errors between the measurement and the simulation of the temperature and the thermal error are 2 ~C and 2.5 pm, respectively. The researching results demonstrate that the FEM model can predict the thermal error and temperature distribution very well under specified operating condition. Moreover, the uneven temperature gradient is due to the asynchronous dual-drive structure that results in thermal deformation. Additionally, the positioning accuracy decreases as the measured point became further away from the motor, and the thermal error and equilibrium period both increase with feed speeds. The research proposes a systematical method to measure and simulate the boring machine transient thermal behaviors.

Research trends in methods for controlling macro-micro motion platforms

With ongoing economic,scientific,and technological developments,the electronic devices used in daily lives are developing toward precision and miniaturization,and so the demand for high-precision manufacturing machinery is expanding.The most important piece of equipment in modern high-precision manufacturing is the macro-micro motion platform(M3P),which offers high speed,precision,and efficiency and has macro-micro motion coupling characteristics due to its mechanical design and composition of its driving components.Therefore,the design of the control system is crucial for the overall precision of the platform;conventional proportional–integral–derivative control cannot meet the system requirements,and so M3Ps are the subject of a growing range of modern control strategies.This paper begins by describing the development history of M3Ps,followed by their platform structure and motion control system components,and then in-depth assessments of the macro,micro,and macro-micro control systems.In addition to examining the advantages and disadvantages of current macro-micro motion control,recent technological breakthroughs are noted.Finally,based on existing problems,future directions for M3P control systems are given,and the present conclusions offer guidelines for future work on M3Ps.

Power Supply of Macro-Micro Driven Linear Piezoelectric Motor

To investigate a novel macro and micro driven linear piezoelectric motor composed of an ultrasonic motor with macro movement and a piezoelectric actuator with micro movement,a digital signal processing(DSP)based macro and micro power supply is designed,which fits the new linear piezoelectric motor.The power supply comprises a control circuit,a voltage conversion circuit,an amplifier circuit,a half-bridge module,an optical isolatorsdrive circuit,etc,where the DSP of TMS320F28335 is used as the controller.When the linear piezoelectric motor working in a macro driven state,the power supply outputs alternating currents with high frequency and high voltage,which drives the linear piezoelectric motor dynamically at an ultrasonic frequency;while working in the micro driven state,the power supply outputs direct currents with high voltage,which drives the linear piezoelectric motor in micro driven statically.Here a prototype of the macro-micro power supply is designed.After a series of experiments on the power supply with and without loads,the results show that the power supply can drive and control the macro micro driven linear piezoelectric motor,and realizes quick and seamless switch between macro and micro drive.In addition,the power supply can drive and control the ultrasonic motor or piezoelectric ceramic micro actuator individually.The power supply achieves the multiple parameters of output signals adjustable simultaneously and exhibits good control characteristics.

Cross-scale Correlation of Macro-micro Evaluation Indexes for Asphalt Binder

In order to further study the reliability of macro evaluation indexes,molecular dynamics (MD) was applied to the evaluation of asphalt binder.Micro evaluation indexes (potential energy,surface free energy,solubility parameter and diffusion coefficient) of asphalt binder in different service phases (virgin,modified,aged and rejuvenated) were simulated.Combined with the variation characteristics of asphalt binder macro evaluation indexes (permeability,ductility,viscosity and softening point) in different service phases,the cross-scale correlation of macro-micro evaluation indexes was explored.The results show that the macro and micro evaluation indexes of asphalt binder have different characteristics in different service phases.The essence of the variation in the properties of asphalt binders is the difference in micro composition.In addition,there is a certain correlation between macro and micro evaluation indexes,which can be described by the gray relation theory.The cross-scale correlation of macro-micro evaluation indexes can provide a certain theoretical basis for the development of asphalt binder.

宏/微双重驱动机器人系统的研究现状与关键技术

宏/微双重驱动机器人系统的综合性能优于采用单一驱动方式的机器人系统。在总结了宏/微双重驱动机器人系统的概念、特点、组成结构的基础上,分析了该领域国内外的最新动态及其关键技术,为宏/微双重驱动机器人的进一步设计与开发提供了翔实的信息与参考依据。作为对宏/微技术的总结与应用,提出了一种新颖的集成式宏/微双重驱动柔性并联机器人系统,可在立方厘米级的工作空间内达到纳米级的运动精度。

压电型宏微双驱动精密定位系统点位协调控制

设计了基于压电型微驱动器的宏微双驱动精密定位系统,宏动台由伺服电动机直接驱动,微动台由压电陶瓷驱动器和弹性铰链构成,并由压电陶瓷驱动器驱动。微动台安装在宏动台上,微动台和宏动台是串联关系。宏动台用于实现大行程微米级定位,而纳米级定位由微动台实现。利用基于运动控制卡的开放伺服功能来协调宏微工作台之间的控制,而位置反馈由两个高精度光栅完成,精度检测由激光干涉仪完成。当宏动台运动结束后,微动台根据测得的定位误差做出补偿进给。实验表明,在行程100 mm的范围内每隔1 mm采集一点,误差控制在±100 nm以内。

具有角度修正功能的大行程二维纳米工作台

基于宏微组合驱动方式,提出一种具有角度修正功能的大行程二维纳米工作台设计方案来减小精密测量系统中由于工作台定位及角度误差引入的测量误差。首先,从原理上对设计方案进行了论证。该方案中宏动工作台和微动工作台共用位置反馈系统构成闭环控制,并基于压电陶瓷致动器及柔性铰链设计的六自由度微动工作台对宏动工作台进行直线定位误差及角度误差的综合补偿。然后,基于设计方案设计了宏动工作台及微动工作台的结构。最后,对安装调试后的宏微工作台系统进行了直线组合定位测试及角度误差修正测试。实验结果表明,该工作台系统的宏动行程达到了200mm×200mm;在闭环控制下,通过六自由度微动工作台的补偿作用可使各角度偏差由上百秒降至10″以内,由此工作台系统在全行程内的直线定位误差可由3μm降至25nm以内。实验结果验证了提出的组合定位系统的有效性。

宏/微双重驱动技术的研究和应用现状

宏/微双重驱动技术因具备大行程、快速响应、高精度定位等特点,近年来在微操作领域得到了广泛的应用。总结了目前常用的宏/微双驱动的宏、微定位部件,并分析了它们各自的优缺点及使用范围;并介绍了常见的宏/微双重驱动系统的集成方式,以及国内外这方面研究取得的成果。为即将从事这方面研究的人员提供了很好的参考。

基于显微视觉的宏/微双驱动微动台系统

提出了基于PZT的宏/微双重驱动精密定位机构,采用混合式步进电动机直接驱动宏动平台,实现系统大行程微米级精度定位,安装在宏动平台上的压电陶瓷驱动微动平台,实现纳米级的分辨率和定位精度,以高频响动态补偿系统的定位误差。采用显微视觉反馈控制微动台的移动和定位,实现定位机构的全闭环反馈控制,同时提出了带运动规划和估算的运动控制策略,提高了系统的运行速度。实验研究表明:系统的动态和稳定性能良好,该微动台的最大行程80mm,定位精度1μm。

基于TMS320DM642和S3C2410的细胞注射装置控制系统

为解决目前细胞注射装置普遍采用的在显微镜下手动操作的机构效率低下、响应速度慢等问题,提出了基于DSP和ARM嵌入式系统的细胞注射装置。该装置利用基于TMS320DM642的图像处理子系统完成图像的采集、处理并将处理的结果保存在特定的存储器内;同时,基于S3C2410的控制子系统完成人机交互、宏/微双精度微动台控制等功能,并利用TMS320DM642的HPI接口进行DSP与ARM处理器的数据交互。模拟结果表明,系统控制自动定位精度达到0.1μm,提高了系统运动精度,图像处理速度达到11 frame/s。

宏/微双驱动定位台显微视觉自动聚焦清晰度评价方法

在基于光学显微镜的微操作定位中,为了克服显微镜头在拍摄图像过程中的视场狭小、焦深短等问题,综合利用了基于梯度场的图像清晰度评价方法和基于小波变换的图像清晰度评价方法。将显微镜头安装在一维宏/微双精度定位平台上,用以保证显微镜头的运动精度。为了防止系统聚焦于面积最大的背景部分,采用了仅对目标区域进行清晰度评价计算的方法,保证系统仅对操作感兴趣的目标进行自动聚焦。通过以上技术实现定位机构的全闭环反馈控制。实验研究表明:系统的动态和稳定性能良好,系统的响应速度由0.3帧/s提高到3帧/s,同时根据清晰度确定的空间位置关系还可以进行防碰撞控制。

基于显微视觉的宏／微双重驱动微动台的自动标定

提出了基于压电技术的微操作系统的自动标定方法,采用混合式步进电机直接驱动的宏动平台,实现系统大行程宏动定位,安装在宏动平台上的压电陶瓷驱动的微动平台和精密光栅,实现亚微米级的分辨率和定位精度,通过以上两部分实现定位机构的全闭环反馈控制,采用显微视觉反馈获取微动台操作器在图像中的位置信息进行标定。实验结果表明:系统的动态和稳定性能良好,自动标定运算速度快,运行速度达到11 frame/s,实现了对系统的精确标定,标定精度达到0.1μm。

五自由度宏/微双重驱动并联机构及其运动学分析

提出了一种扫描电子显微镜用4-PSPS/PRPUR五自由度宏/微双重驱动并联机构,该机构可以实现三维移动和两维转动。采用螺旋理论分析了该机构的自由度,采用基于螺旋系线性相关性的并联机构输入选取判别方法,选取了驱动副并进行了合理性判别。在此基础上对该双重驱动并联机构进行了位置反解分析,结合其应用给出了数值算例,并进一步对该机构进行了速度、加速度分析,且给出了速度、加速度的数值算例。

基于Hexapod的精密跟瞄平台研究

针对精密光学设备的空间应用,设计了基于并联机构的空间高稳定精密跟瞄系统。利用所设计的宏/微双重驱动复合作动器和精密铰接元件,研制了精密跟瞄Hexapod平台原理样机,考虑到精密跟瞄系统的特点,开发了包括宏动控制系统、微动控制系统和检测系统在内的实验测试系统,并利用实验初步测试了Hexapod平台原理样机关键性能。由实验结果可知,平台原理样机的转动范围超过10°,最高开环转动速度大于5deg/s,经压电微动部分补偿后的平台静态定位误差小于5μrad,通过主动控制使扰动振幅衰减至噪声水平,可用于驱动有效载荷以较高的速度在较大范围内搜索目标并具有较好的静态定位精度和稳定性。

压电型宏/微双驱动精密定位机构的建模与控制

提出了基于PZT的串联型宏/微双驱动精密定位系统,宏动台由步进电动机直接驱动,微动台由压电陶瓷驱动器驱动。将微动台安装在宏动台上,宏动台以地面为定位参考物,微动台以宏动台为定位参考物;宏动台实现大行程微米级定位,微动台实现纳米级的定位精度。采用基于机器视觉的视觉伺服来协调控制系统宏动和微动各自的控制部分,将距离信号作为控制阈值,实现整个定位结构的全闭环反馈控制。测试表明:系统的动态以及稳定性良好,工作行程为80mm,定位稳定时间小于40ms,重复定位精度为100nm。

大行程超精密工作台的研究

该微动平台采用花岗岩作为机架材料,以压电陶瓷直线电机驱动平台,选择RENISHAW的RGH25光栅作为反馈和宏微双驱动协调控制伺服输出,并提出了提高定位精度的方案。为研究微动工作台提供了参考。通过实验对工作台的性能进行分析,证实平台设计的可行性。

三维微细电解加工装备的研制与开发

设计开发了一台微细电解加工装置。该装置采用龙门固定式结构,具有高精密的压电陶瓷微动工作台,可通过CCD观察整个加工过程;在宏微结合的驱动控制下,可进行各种微细孔、微细轴以及复杂微细结构的高精度微细电解加工。

跨尺度二维工作台系统研制

为实现大行程、纳米分辨力的定位目标,研制了跨尺度二维工作台系统。采用大行程宏动台和六自由度微动台组合的方式,搭建了宏/微双驱动高精度二维工作台系统。该系统利用机器视觉技术,采用图像处理方法确定系统中各个零件的位置和方向,宏动台高速移动实现粗定位,通过微动台与宏动台的循环配合工作,最终实现二维工作台系统的纳米级定位精度。实验结果表明,200mm×200mm二维工作台的定位精度在0.6μm左右,该工作台系统具备了大行程、定位时间快、智能化等优点。

宏/微双重驱动的新型直线电机研究

大行程、高精度,同时易于小型化的移动机构是先进制造业等领域要解决的关键问题之一,综述了现有宏/微双重驱动机构和直线超声电机的研究进展和存在问题,提出了一种宏微双重驱动新型直线压电电机,使其既能与超声电机一样,直接驱动、响应快、不受磁场干扰实现宏驱动;又能与微驱动一样,精密定位,实现微驱动,并把宏微运动结合起来,在一个电机上同时实现宏微驱动,通过有限元分析软件,计算复合振子的振动模态和静态变形,分析了宏微驱动原理,给出了宏微驱动新型直线电机驱动电源的设计方案。