基于PZT的非球面能动抛光盘定位误差分析

研制了一个口径为100 mm、含19个PZT驱动器的非球面能动抛光磨盘,用于加工口径为350 mm、k=-1.112 155、顶点半径为840 mm的双曲面镜。为研究定位误差对非球面能动抛光磨盘输出面形精度的影响,对磨盘上任意点所需变形量δ以及由定位误差引入的变形量误差Δδ进行了理论公式推导,并利用有限元分析方法计算得到了当非球面能动抛光磨盘中心到非球面工件中心的距离L为120 mm且δL分别为0,-1.0,-0.5,0.5,1 mm时,非球面能动抛光磨盘输出面形与理论面形比较剩余残差RMS相应分别为0.329,0.454,0.366,0.367,0.461μm,定位误差导致剩余残差RMS分别相应增加0,38%,10.9%,11.2%,40%。因此,定位误差应该控制在±0.5 mm以内。

PZT电滞曲线和回零偏差的测量及其对扫描成像的影响

本文利用迈氏干涉法测量压电陶瓷扫描头（ＰＺＴ）的电滞曲线和灵敏度因子。作出了ＰＺＴ的电滞曲线，得到了灵敏度因子，测出了由电滞特性造成的扫描头不同电压正负回零偏差。

基于PZT管支撑结构的三轴加速度计设计及实验误差分析

以提升毫米尺度三轴压电加速度计灵敏度为目标,设计了以3个长度12 mm轴向极化的PZT管作为敏感和支撑结构的三轴加速度计,给出了空间加速度信号的解算方法。通过3个PZT管关于器件结构中心轴对称布置,该加速度计实现了对三轴加速度大小和方向的精确解算。数值仿真得到了3个PZT管在[100,1000]Hz加速度的输出电压幅频特性曲线及器件三轴灵敏度。研制了三轴传感器样件,实验表明其x、y、z轴灵敏度分别为535、541、542 mV/g,三轴灵敏度标准差为3.8。系统分析了加工误差对实验结果的影响程度,分析并解释了实验与仿真数值间存在误差的原因,为三轴加速度计敏感与支撑结构的一体化设计提供了借鉴。

PZT移相和CCD非线性对高精度球面面形检测的影响

为了提高球面面形的检测精度,对移相菲索干涉仪的球面测量方法中影响高精度球面面形检测的压电陶瓷晶体(PZT)移相误差和电荷耦合探测器(CCD)非线性误差进行探讨.通过理论分析和数值模拟的方法分别对PZT移相误差、CCD非线性误差进行具体分析,着重研究PZT移相误差和CCD非线性误差的综合影响.由五步移相算法,推导得出PZT和CCD的综合误差公式,对影响综合误差大小的主要因素如CCD二次非线性系数、条纹对比度和被检面曲率半径与口径的比值等进行分析.结果表明,提出的控制PZT和CCD综合误差影响的准则和相应的减小误差影响的方法,可以提高球面面形的检测精度.

Spatial phase-shifting interferometry with compensation of geometric errors based on genetic algorithm(Invited Paper)

We propose a novel spatial phase-shifting interferometry that exploits a genetic algorithm to compensate for geometric errors. Spatial phase-shifting interferometry is more suitable for measuring objects with properties that change rapidly in time than the temporal phase-shifting interferometry. However, it is more susceptible to the geometric errors since the positions at which interferograms are collected are different. In this letter, we propose a spatial phase-shifting interferometry with separate paths for object and reference waves. Also, the object wave estimate is parameterized in terms of geometric errors, and the error is compensated by using a genetic algorithm.

The holographic reconstructing algorithm and its error analysis about phase-shifting phase measurement

Phase-shifting measurement and its error estimation method were studied according to the holographic principle.A function of synchronous superposition of object complex amplitude reconstructed from N-step phase-shifting through one integral period(N-step phase-shifting function for short)was proposed.In N-step phase-shifting measurement,the interferograms are seen as a series of in-line holo-grams and the reference beam is an ideal parallel-plane wave.So the N-step phase-shifting function can be obtained by multiplying the interferogram by the original reference wave.In ideal conditions,the proposed method is a kind of synchro-nous superposition algorithm in which the complex ampli-tude is separated,measured and superposed.When error exists in measurement,the result of the N-step phase-shifting function is the optimal expected value of the least-squares fitting method.In the above method,the N+1-step phase-shifting function can be obtained from the N-step phase-shifting function.It shows that the N-step phase-shifting function can be separated into two parts:the ideal N-step phase-shifting function and its errors.The phase-shifting errors in N-steps phase-shifting phase measurement can be treated the same as the relative errors of amplitude and intensity under the understanding of the N+1-step phase-shifting function.The difficulties of the error estimation in phase-shifting phase measurement were restricted by this error esti-mation method.Meanwhile,the maximum error estimation method of phase-shifting phase measurement and its formula were proposed.

集成式6自由度微动并联机器人系统

基于机构、驱动、检测一体化的思想,研制出了压电陶瓷驱动的6自由度集成式并联微动机器人,对该机器人的机构、驱动、检测、控制及误差补偿方法进行了研究。采用6自由度(6-SPS)并联结构设计了微动并联机器人的构型,对结构参数进行了优化,并进行了运动空间分析和刚度分析。基于模块化设计思想将压电陶瓷驱动电源、微位移传感器检测电路、中央控制器组合在一起,通过自定义的内部总线相连构成了并联机器人的驱动和控制系统。最后,给出了该机器人位姿测量方法,并分别在压电陶瓷的开环与闭环控制状态下进行位姿测量,进而实现误差补偿。实验结果表明:该并联微动机器人可实现10 nm平动重复定位精度;0.0001°转动重复定位精度;具有定位精度和可靠性高,使用灵活方便的特点,满足多自由度精密定位的要求。

微驱动定位系统及其在误差补偿机器人中的应用

介绍了基于偏摆误差补偿的高速高精度机器人系统组成及偏摆误差补偿原理,利用有限元分析软件ANSYS,设计了双层平行板弹性铰链结构、压电陶瓷(PZT)直接驱动的微位移工作台。采用模糊PI控制算法对微动工作台进行闭环控制,既利用模糊控制灵活、适应性强的优点,又利用PI控制精度高的优点。实验结果验证了模糊PI控制算法的有效性,采用微动工作台补偿偏摆误差,机器人的运动性能得到较大提高。

运放对压电陶瓷驱动电路系统精度影响的研究

为了在光刻机投影物镜中使用压电陶瓷对像质补偿镜组进行精密定位,设计了一种以集成运算放大器构成的压电陶瓷驱动电路。针对光刻物镜中压电陶瓷的亚微米量级高精度定位要求,研究了驱动电路的系统精度要求,并对系统误差进行分解,着重分析了运算放大器放对系统精度的影响。首先,分析运放失调误差的影响;其次,使用PSpice仿真获得运放的固有频率特性,分析工作带宽下运放有限开环增益的影响;然后,对运放反馈网络的影响进行分析;最后,分析运放输出噪声的影响。计算表明,在最坏情况下该压电陶瓷驱动电路中由运算放大器引起的系统误差小于130mV,满足系统误差分配的要求。试制了系统样机并进行了验证实验,实验结果表明由运放引起的系统误差不超过100mV,与理论分析的结果符合。

基于实时误差补偿的精密定位系统的研究

介绍了基于实时误差补偿的精密定位系统的组成,分析了系统的偏摆振动模型,讨论了偏摆误差检测原理。利用有限元软件ANSYS,设计了采用双层平行板弹性铰链结构、基于PZT直接驱动的微驱动补偿工作台。实验结果证明,采用实时误差补偿技术,定位系统的运动性能得到较大提高。

大行程精密定位平台偏摆误差的补偿方法

精密定位平台在导轨动连接处刚度较差,在高速高动态工作中这里易产生偏摆振动。为了减小偏摆误差对定位平台的影响,提高定位精度,通过对直线电机驱动、气浮导轨支撑和导向的高精度定位平台进行研究。根据定位平台偏摆误差的动态特性,采用偏摆误差补偿方法,设计一种偏摆误差检测系统,采用平尺和微位移传感器相结,具有高频响、非接触式的特点。设计了一种基于压电陶瓷驱动的x,y两维微位移补偿机构。同时,通过将气浮导轨滑块副简化成弹簧、质量和阻尼相结合的系统,推导出了定位平台两自由度的偏摆振动模型。基于误差补偿系统的偏摆误差补偿实验表明,精密定位平台的定位精度得到了较大提高,定位平台的定位精度优于2μm。

用于误差补偿的二维微量进给刀架

研制了一种用于误差补偿的二维微量进给刀架 ,采用压电陶瓷传感器 (PZT)作为误差补偿执行元件。

2-D Statistical Damage Detection of Concrete Structures Combining Smart Piezoelectric Materials and Scanning Laser Doppler Vibrometry

In the present study a new structural health monitoring (SHM) technique isproposed as well as a new damage index based on 2-D error statistics. The proposedtechnique combines the electromechanical impedance technique (EMI) which is based onthe use of piezoelectric Lead Zirconate Titanate (PZT) patches and Scanning LaserDoppler Vibrometry (SLDV) for damage detection purposes of concrete structures andearly age monitoring. Typically the EMI technique utilizes the direct and inversepiezoelectric effect of a PZT patch attached to a host structure via an impedance analyzerthat is used for both the actuation and sensing the response of the PZT-Host structuresystem. In the proposed technique the attached PZTs are actuated via a function generatorand the PZT-Host structure response is obtained by a Scanning Laser DopplerVibrometer. Spectrums of oscillation velocity of the surface of the attached PZTs verticalto the laser beam versus frequency are obtained and are evaluated for SHM purposes.This damage detection approach also includes the use of a damage index denoted asECAR (Ellipse to Circle Area Ratio) based on 2-D error statistics and is compared to theRoot Mean Square Deviation (RMSD) damage index commonly used in SHMapplications. Experimental results include ascending uniaxial compressive load ofconcrete cubic specimens, ascending three point bending of reinforced concrete beamspecimens and early age monitoring of concrete. Results illustrate the efficiency of theproposed technique in damage detection as well as early age monitoring as, in the firstcase, both severity and location of damage can be determined by examining the values ofdamage indices for each damaged state and in the early age monitoring case damageindices follow the strength gain curve.