光刻物镜中光学元件精密轴向调整机构的设计与分析

柔性铰链与高准确度驱动器的结合是实现光学元件轴向精密调节的重要方法.本文介绍了一种采用柔性铰链的轴向精密调节机构,推导并得出了其实现精密调节的原理.通过对应用柔性调节机构的一种典型光机系统的刚度分析,得到在不超过柔性铰链材料屈服应力情况下,光学元件的最大轴向位移可以达到200μm以上;同时,对一种典型参量的柔性结构做了模态分析,得到其一阶固有频率为185.1Hz,证明了调节机构的固有频率满足工作要求.分析了驱动力在此种轴向调整机构中对镜片面形的影响,结果表明:调整机构在接近最大允许驱动力作用下对镜片面形影响为4.41nm,说明其对光学元件的面形影响较小.该研究结果为柔性光学元件轴向调节机构的应用提供了有力依据.     

长条镜柔性支撑及点阵结构设计方法

离轴三反光学系统多采用长条形反射镜,为尽可能提高反射镜面形精度,其支撑结构形式多为柔性支撑;为了在保证结构力学性能的基础上满足轻量化的需求,支撑亦多采用壳体点阵结构。本文基于尺寸优化技术,建立了长条形反射镜的参数化有限元模型以及双轴圆弧切口柔性铰链支撑的多参数优化模型,分别应用可行方向法及自适应响应面优化算法得到了质量约束下刚度最优的反射镜面板、筋板厚度参数以及刚度约束下镜面面形最优的柔铰支撑几何尺寸参数,并应用参数试验方法对该柔性支撑安装角度及安装轴向位置进行了独立变量的影响分析。对于背板的设计,本文提出了一种基于点云三维重建的点阵结构设计仿真优化方法,采用贪婪三角化投影算法对点阵结构包络生成的点云进行网格重构,保证了点阵结构模型的连续性与真实性。经过仿真验证,优化参数下重力、温度、强迫位移各工况下反射镜综合面形误差（0.018λ）和装调方向重力下刚体位移（0.007 mm）均达到最优。表明基于点云三维重建的点阵结构设计仿真优化方法合理可行,可推广应用于类似结构形式的反射镜支撑。     

一种精级回转驱动机构的研究

两轴四框结构光电吊舱,内框多采用力矩电机直驱,稳定精度仅为数10 μrad。为达到更高精度的μrad量级,提出一种压电陶瓷驱动柔性支承的精级回转驱动机构,作为光电吊舱的内框驱动。介绍了精级回转驱动机构的构型方案,并对压电陶瓷的驱动能力进行了探讨,对柔性支承的回转刚度、固有频率、几何参数进行了详细设计。建立了机电仿真模型,制造了原理样机并进行了性能测试,其主要性能指标为:行程509.1 μrad,分辨率优于0.5 μrad,1 Hz、100 μrad的正弦信号跟踪误差小于3 μrad,固有频率约1 kHz,均满足设计目标。     

两轴四框架结构光电稳瞄吊舱减振器谐振频率计算与试验

根据振动理论分析两轴四框架系统选择减振器的要点,对某型直升机内外框架刚性连接的吊舱进行扫频振动试验,测量了谐振频率和谐振点的扫频放大率,绘制了放大率曲线。通过使用放大率曲线计算内外框架刚性连接时系统的三向刚度。并根据减振器刚度值,利用弹簧串联刚度的计算方法计算了使用减振器系统的三向刚度和谐振频率。重新进行试验后,结果表明系统谐振频率和放大率都满足要求。该结构使用减振器的要点是：减振器放大段位于伺服带宽内,系统谐振频率避开外界扰动频率以及放大率应尽可能小。     

基于柔性铰链的光纤光栅二维加速度 传感器的优化设计

为实现对待测表面两个方向的振动监测,基于圆形柔性铰链设计了一种布拉格光栅双向加速度传感器.首先,推导出该传感器的谐振频率及灵敏度的理论公式,然后基于圆形铰链刚度的理论公式,推导并验证了铰链的刚度经验公式.通过MATLAB对传感器的数学模型进行优化设计,得到在满足工作要求时,传感器灵敏度达到最大时的尺寸参数.激振实验结果表明,该传感器的谐振频率约为368Hz,灵敏度约为107.3pm/g,横向抗干扰度为4.8%,谐振频率和灵敏度理论值与实际值的误差分别为-4.2%和7.0%.     

辐射与发光 光辐射与辐射源

O432.1 2006042817同步辐射光束线中柔性铰链的设计=Design of flexurehinge in beamline of synchrotron radiation[刊,中]/陈贵敏(西安电子科技大学机电工程学院.陕西,西安(710071)) ,韩琪…∥光电工程.—2006 ,33(3) .—119-122为同步辐射光束线设计了一种新型的柔性铰链—直圆倒角复合柔性铰链。分析计算并通过实验验证了直圆倒角复合柔性铰链性能。与直圆柔性铰链相比,直圆倒角—2—复合柔性铰链具有柔度大、转动精度高等优点,可在不损失精度的情况下大大提高微调机构的柔性;在要求最大转角一定的情况下,可大大降低对致动器驱动能力的…     

用于地基望远镜的高分辨率倾斜镜设计

根据多镜面地基望远镜在近红外实现共相衍射极限成像的需求,提出了一种基于压电堆栈致动器的高分辨率倾斜镜设计方案。该方案以哑铃型柔性铰链和菱形位移缩小结构(RADS)作为倾斜镜的运动传递元件,压电堆栈致动器(PSA)作为动力元件,并使用电涡流传感器作为角度测量部件。介绍了高分辨倾斜镜的工作原理,并对哑铃型柔性铰链和菱形位移缩小结构进行设计。柔性铰链和位移缩小结构的关键结构参数均采用理论计算、实验和仿真进行优化。建立倾斜镜模型,利用理论计算和有限元仿真软件分别计算倾斜镜的倾斜角度和分辨率。实验结果表明:设计的倾斜镜角度分辨率达到0.017″,最大倾斜角度为14.6″,谐振频率为136.97 Hz,与有限元仿真结果相吻合,满足地基望远镜系统衍射极限成像的要求。     

双原子分子体系传能机制的分子动力学模拟

本文应用分子动力学计算机模拟方法研究同核双原子分子晶体体系的内部传能机制。计算了不同势参数下分子内部的振动频率;验证了振动势能项将以与平动、振动、转动各自由度一样的权重分配分子能量的理论;计算了不同振动频率下的弛豫速率。     

光学元件狭缝柔性调节机构的设计与分析

设计了一种狭缝柔性结构的光学元件调节机构,使光学元件在具备较高调节精度的同时,保持较高的导向精度。采用弹性力学应力函数法分析了狭缝柔性结构的刚度,以径向刚度与轴向刚度的比值为目标函数,对狭缝柔性结构尺寸参数进行了优化,在不超过柔性结构材料屈服应力等约束条件下,刚度比最优值达到1 573.6,较大的刚度比值可以减小调节机构的耦合位移,从而提高机构的导向精度。该结构加工装配方便,可实现三自由度(θx-θy-Z)调节。对优化后的柔性结构进行仿真分析,结果表明:径向刚度与轴向刚度比值的仿真值为1 660.4,解析值与仿真值误差为5.23%,证明了刚度分析方法的有效性。优化后的结构,轴向调节行程为2.09 mm,绕x轴偏转角度调节行程为±16.6 mrad,绕y轴偏转角度调节行程可达到±14.4 mrad,满足光学元件调节的大行程要求。     

基于Nelder-Mead单纯形法的逆合成孔径激光雷达联合补偿成像算法

逆合成孔径激光雷达(ISAL)的调制信号具有高频率、大带宽的特性,使传统逆合成孔径雷达的"一步一停"模型不再适用。通过建立精确的ISAL成像模型,分析了ISAL成像过程中存在的平动误差、转动误差和模型误差。针对传统ISAL采用平动、转动分离补偿时,由于平动误差补偿存在残余误差而影响转动误差补偿的问题,因此提出基于Nelder-Mead单纯形法和拟牛顿法的联合补偿成像算法。该算法首先采用Nelder-Mead单纯形法对目标运动参数进行优化迭代搜索,将得到的优化解作为运动补偿项对三类误差进行全局补偿,然后利用拟牛顿法补偿残余误差。仿真实验结果表明,与传统分离补偿算法相比,本文算法可以精确估计目标的运动参数,获得聚焦良好的高分辨率ISAL二维图像。     

一种新型微机电系统扫描镜的谐振频率研究

在微光机电系统(MOEMS)技术的基础上,采用绝缘体上硅(SOI)的体硅加工工艺,设计并加工制作了一种新型的静电驱动的谐振式微机电系统(MEMS)扫描镜。介绍了其基本工作原理及结构设计特点;理论计算了圆形和方形两种结构的尺寸扫描镜的谐振频率,并利用ANSYS有限元软件进行仿真;设计并搭建了一个简单易操作的光学测试系统,对研制出的MEMS扫描镜(7.1mm×5.2mm)进行扫描角度测试。利用该器件参数激励的迟滞频率特性,对其谐振频率进行实际测量。同时,为验证其所测谐振频率的准确性,利用激光多普勒测振(LDV)系统对其进行测试。在工作电压10V,方形和圆形扫描镜的驱动频率分别为556Hz和596Hz时,机械扫描角度分别可达到约6°和5°,谐振频率分别约为300Hz和277Hz。并分析误差产生的原因及其结果。     

三种不同型线柔性弹簧的有限元分析及对比研究

柔性弹簧对于低温制冷机的间隙密封及可靠性具有重要作用,文中在总结国内外柔性弹簧型线的基础上,针对用于低温制冷机的三种典型柔性弹簧,采用Ansys软件对其应力分布、径轴向刚度以及自然频率等特性进行了数值模拟和对比分析,该研究为探索具有优良性能的新型线结构的柔性弹簧指明了方向.     

柔性铰链的有限元法设计与分析

大变形、小应力、小中心漂移的柔性铰链的研制一直是柔性铰链研究的难题。本文在参考国外某款柔性铰链的基础上,利用V型结构设计、叠加理论和对称布置方法设计了一种新型的柔性铰链。针对这种柔性铰链的设计进行了概念性研究,建立了铰链的数学模型,研究了这种新型柔性铰链的性能。有限元方法分析表明,该设计方法增加了铰链柔性部分的长度,降低了它的中心漂移和最大应力,得到其最大转角约为16°,最大中心漂移为3.557μm,最大应力为499.8 MPa,满足了最初的设计指标要求。结果证明该铰链具有一定的实用价值。     

An Investigation of Cricoarytenoid Joint Mechanics Using Simulated Muscle Forces

Rotational and translational stiffnesses were calculated for arytenoid motion about the cricoarytenoid joint. These calculations were obtained from measurements on five excised human larynxes. For each larynx, known forces were applied to the arytenoid cartilage, and three markers were tracked as a function of applied forces. Assuming rigid body motion, arytenoid translations and rotations were computed for each applied force. Translational stiffnesses were obtained by plotting force versus displacement, and rotational stiffnesses were calculated by plotting torque versus angular rotation. A major finding was that the translational stiffness along the anterior-posterior direction was three times as great as the translational stiffnesses in the other two directions. This nonisotropic nature of the stiffnesses may be an important consideration for phonosurgeons who wish to avoid subluxation of the cricoarytenoid joint in patients. The computed rotational and translational stiffnesses currently are being implemented in 2D and 3D models. These stiffness parameters play a vital role in prephonatory glottal shaping, which in turn exerts a majorinfluence on all aspects of vocal fold vibration, including fundamental frequency, voice quality, voice register, and phonation threshold pressure.     

Magnetic resonance elastography of the supraspinatus muscle: A preliminary study on test-retest repeatability and wave quality with different frequencies and image filtering

The purpose of this study was to determine an optimal condition (vibration frequency and image filtering) for stiffness estimation with high accuracy and stiffness measurement with high repeatability in magnetic resonance elastography (MRE) of the supraspinatus muscle. Nine healthy volunteers underwent two MRE exams separated by at least a 30 min break, on the same day. MRE acquisitions were performed with a gradient-echo type multi-echo MR sequence at 75, 100, and 125 Hz pneumatic vibration. Wave images were processed by a bandpass filter or filter combining bandpass and directional filters (bandpass-directional filter). An observer specified the region of interest (ROI) on clear wave propagation in the supraspinatus muscle, within which the observer measured the stiffness. This study assessed wave image quality according to two indices, as a substitute for the assessment of the accuracy of the stiffness estimation. One is the size of the clear wave propagation area (ROI size used to measure the stiffness) and the other is the qualitative stiffness resolution score in that area. These measurements made by the observer were repeated twice at least one month apart after each MRE exam.This study assessed the intra-examiner and observer repeatability of the stiffness value, ROI size and resolution score in each combination of vibration frequency and image filter. Repeatability of the data was analyzed using the intraclass correlation coefficient (ICC) and 95% limits-of-agreement (LOA) in Bland-Altman analysis. The analyses on intra-examiner and observer repeatability of stiffness indicated that the ICC and 95% LOA were not varied greatly depending on vibration frequency and image filter (intra-examiner repeatability, ICC range, 0.79 to 0.88; 95% LOA range, ±23.95 to ±32.42%, intra-observer repeatability, ICC range, 0.98 to 1.00; 95% LOA range, ±5.10 to ±10.99%). In the analyses on intra-examiner repeatability of ROI size, ICCs were rather low (ranging from: 0.03 to 0.69) while 95% LOA was large in all the combinations of vibration frequency and image filter (ranging from: ±62.66 to ±83.33%). In the analyses on intra-observer repeatability of ROI size, ICCs were sufficiently high in the total combination of vibration frequency and image filter (ranging from 0.80 to 0.87) while the 95% LOAs were better (lower) in the bandpass-directional filter than the bandpass filter (bandpass directional filter vs. bandpass filter, ±28.81 vs. ±54.83% at 75 Hz; ±25.63 vs. ±37.83% at 100 Hz; ±34.51 vs. ±43.36% at 125 Hz). In the analyses on intra-examiner and observer repeatability of resolution score, the mean difference (bias) between the two exams (or observations) was significantly low and there was almost no difference across all the combinations of vibration frequency and image filter (range of bias: −0.11–0.11 and −0.17–0.00, respectively).Additionally, effects of vibration frequency and image filter on wave image quality (ROI size and resolution score) were assessed separately in each exam. Both mean ROI size and resolution score in the bandpass-directional filter were larger than those in the bandpass filter. Among the data in the bandpass-directional filter, mean ROI size was larger at 75 and 100 Hz, and mean resolution score was larger at 100 and 125 Hz. Taking into consideration with the results of repeatability and wave image quality, the present results suggest that optimal vibration frequency and image filter for MRE of the supraspinatus muscles is 100 Hz and bandpass-directional filter, respectively.     

锁相环在超导射频技术中的应用

利用压控振荡器锁相环路(VCO-PLL)锁定超导射频谐振腔体的本征频率,使腔体稳定谐振。在原理验证阶段,利用NI-Labview对实验原理做了仿真。得到的仿真结果显示,环路增益选取的不同会直接影响整个系统的锁定状态。在实验测试阶段,根据原理和仿真结果搭建了相应的实验平台,从而得到环路锁定的测试结果。最后在低温超导态测试阶段,用经过验证的实验平台对IMP-HWR010超导腔体进行了频率锁定测试,并得到了腔体频率随氦压变化的实际测量结果,df/dp约为0.73 Hz/Pa。     

Predicting the effects of vertical vibration frequency,combinations of frequencies and viewing distance on the reading of numeric displays

This paper describes a series of experiments to determine the effects of vibration frequency, viewing distance and multiple frequency motions on the reading of numeric characters. Contours of vertical (z-axis) whole-body vibration levels resulting in equal degradation of the reading task were determined over the frequency range 2·8 Hz to 63 Hz. With the seating condition employed, the task was found to be most sensitive to vibration acceleration at a frequency of 11·2 Hz. A marked correlation was observed between reading error and reading speed. The effects of vibration on reading performance were found to be dependent on viewing distance for distance of less than 1·5 m, with the effect increasing as the viewing distance was decreased. The effect of 3·15 Hz vibration was found to increase more rapidly with reductions in viewing distance than that of 16 Hz vibration. The effects of 3·15 and 16 Hz vibration were independent of viewing distance greater than 1·5 m, indicating that the effects of rotational eye motion are dominant at these distances. Four methods were compared for predicting the effects of multiple frequency motion on reading performance given a knowledge of the effect of each component alone. The best predictions of reading error were obtained from the most severe weighted spectral component alone. Inspection of individual subject's data suggests that in many cases the effect of multiple frequency vibration on reading is even less than the effect of the largest sinusoidal component alone.     

转子密封系统流体激振问题的流固耦合数值研究

随着叶轮机械的工作转速越来越高,工程中发生了大量的密封流体激振问题。实验证明,高转速下的流体激振属于自激振动,但采用传统的刚度阻尼线形假设无法模拟出这一物理现象。本文发展了一种高精度的流固耦合计算方法,用这种算法成功地模拟出转子密封系统在高转速下的自激振动,且捕捉到频率锁定的现象,而且发现随着转速的提高,固有频率也增大。另外,本文还得到了压比、预旋度对密封转子自激振动的影响规律。     

柔性铰链的有限元法设计与分析

大变形、小应力、小中心漂移的柔性铰链的研制一直是柔性铰链研究的难题。本文在参考国外某款柔性铰链的基础上,利用V型结构设计、叠加理论和对称布置方法设计了一种新型的柔性铰链。针对这种柔性铰链的设计进行了概念性研究,建立了铰链的数学模型,研究了这种新型柔性铰链的性能。有限元方法分析表明,该设计方法增加了铰链柔性部分的长度,降低了它的中心漂移和最大应力,得到其最大转角约为16°,最大中心漂移为3.557μm,最大应力为499.8 MPa,满足了最初的设计指标要求。结果证明该铰链具有一定的实用价值。