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复杂非球面镜高效超精密车削加工法(英文) 总被引:1,自引:0,他引:1
本文中对复杂面形的非球面镜进行了分类,并从加工方法和加工路径优化设计等方面研究了复杂非球面镜的超精密车削方法.对回转对称的复杂非球面镜进行了加工实验,并借助超精密测量技术对各段曲面进行面形测量,依据测量结果实现面形补偿加工.最终粗糙度Ra达5.14 nm,形状精度P-V值达200 nm.采用提出的方法对非回转对称的非球面阵列进行加工路径设计,根据具体面形进行加工参数选择和实际加工,得到粗糙度Ra为7.81nm的表面.实验结果证明了提出的加工方法高效实用,可以满足大部分复杂非球面的应用需求. 相似文献
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超精密车削金刚石刀具刃口误差的高精度补偿 总被引:1,自引:0,他引:1
超精密车削中的金刚石刀具刃口误差的补偿问题一直是制约高精度非球面车削直接成形的瓶颈技术,尤其对于大相对口径,深度非球面的车削,金刚石刀具刃口误差对最终的面形的影响非常大.传统补偿方法是根据轮廓仪的测量结果对刀具刃口误差进行修正,但是该方法存在测量时间长,高频误差大,加工效率低的缺点,本文最先提出利用车削表面面形误差拟合... 相似文献
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补偿器法检测非球面过程中易出现的误区 总被引:4,自引:0,他引:4
补偿器法是测量非球面反射镜面形误差的一种重要的方法.在检测过程中,各个元件之间的调整会带来初级像差,这是影响最终检测结果的一个关键因素.本文以一个1 m 口径的非球面反射镜为例,首先详述了其面形误差检测的设计和测量过程,然后分析了各个元件的调整会带来相应的初级像差,随后给出了实际检测过程中出现的误区,并对其进行了分析和讨论,结合实际的检测过程得出了相应的判断和消除的方法.最后,分别对300 mm、700 mm 口径非球面反射镜与本文1 m 非球面镜的检测结果进行了比较,证明了该误区会使最后的检测数据发生变化,从而使最后的检测结果失真,并验证了先判别后消除方法的可靠性.最后利用正确的方法,检测得到1 m口径非球面被测镜的RMS 面形误差为0.038 λ,满足指标要求. 相似文献
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本文用He-Ne激光器作光源,把电视摄相机(或CCD摄相机)和微机与泰曼-格林干涉仪结合,组成泰曼-电视-微机系统。利用法线象差补偿法检测非球面面形的原理,根据三个干涉图法,对非球面面形自动扫描、分析,并在计算机的监视器上绘制出被检非球面面形的二维等高线图和三维面形。为了扩大测试范围,设计了万能补偿器,可检测一定范围的抛物面,补偿精度可达0.01λ,也可检测椭圆面和双曲面。 相似文献
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红外探测技术对多目标弹道参数的测量 总被引:11,自引:0,他引:11
在对多目标探测所用传感器的选择、目标提取和数据处理等三方面技术问题进行分析论证的基础上,提出了一种新的多、弱、小、暗目标近地弹道参数测量方法。采用红外热像仪合理布站,对运动的多个目标进行空间定位;采集多目标近地区域的下落图像,拟合出相应的轨迹,然后根据多条轨迹得到诸如目标空间坐标、轨迹、速度等弹道参数。这种方法可用于测量靶场落点和近地轨迹等;尤其是在对子母弹子弹群的近地弹道参数及落点的测量中,通过后期处理,可快速精确地报出各子弹的落点坐标。 相似文献
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在膜结构找形中,力密度法引入了"力密度"的概念,使问题简化。但力密度法需要多次试算后才能确定合适的力密度取值,这给找形过程带来困难。该课题组对力密度法的找形过程进行改进,避开其中"力密度"的概念,使找形计算过程简洁高效。该文即对这种"改进力密度"法进行了试验研究,以验证该方法的正确性。试验模型为一平面尺寸为4m×4m柔性索边界、四点支承的马鞍形张拉膜结构。张拉过程采用应力和位移同时控制,量测模型零状态、中间状态和张拉成形后状态边索和膜面的应变值及膜面监测点的空间坐标。通过试验值与理论值在膜面应变、索应变及膜面空间坐标的比较及与ANSYS法、解析法的比较,说明改进力密度法是正确的,可用于实际工程的膜结构找形分析。另外,通过本次实验,我们对膜面应变的量测也得到了一些经验教训。 相似文献
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现有的法矢量测量技术无法满足测量准确度和实时性的双重要求,法矢量计算方法不能适用于不同曲率的曲面。利用双目立体视觉,本文提出了一种基于曲率自适应的法矢量测量方法。首先,在双目立体视觉的基础上,基于变曲率曲面特征建立制孔区域曲面模型,提出投影点的布局方法;然后,基于三维重建的投影点数据,提出了基于曲面曲率自适应识别的法矢量计算方法;最后,针对小曲率曲面样件的测量结果,与三坐标测量仪测得的法矢量进行对比,用以验证本双目视觉测量方法的精度。实验结果表明:该方法测量法矢量误差为1.6°。该方法可有效提高法矢量测量的准确度,满足大型航空零件现场测量的工程要求。 相似文献
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针对白车身视觉检测系统中传感器数量多、种类各异、分布空间大、位置关系复杂等问题,提出了一种适用于工业现场的多视觉传感器全局校准技术。基于坐标系间接统一法,设计多个精密立体靶标作为坐标系转换中介,利用激光跟踪仪获取现场校准数据,在单位四元数数学模型的基础上,求解两坐标系间最优转换矩阵,将固定式传感器和柔性传感器的测量坐标系统一到全局坐标系。该方法已在某企业在线测量项目中成功应用,现场只需完成传感器坐标系与全局坐标系转换关系标定,降低了复杂现场环境对多传感器全局校准的限制,简化了校准过程,提高了环境适应性,校准后检测系统各向测量精度均优于±0.2 mm,满足白车身在线测量精度要求。 相似文献
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Lee YC Kuo SH 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(1):114-120
A new acoustic transducer and measurement method have been developed for precise measurement of surface wave velocity. This measurement method is used to investigate the acoustoelastic effects for waves propagating on the surface of a polymethylmethacrylate (PMMA) sample. The transducer uses two miniature conical PZT elements for acoustic wave transmitter and receiver on the sample surface; hence, it can be viewed as a point- source/point-receiver transducer. Acoustic waves are excited and detected with the PZT elements, and the wave velocity can be accurately determined with a cross-correlation waveform comparison method. The transducer and its measurement method are particularly sensitive and accurate in determining small changes in wave velocity; therefore, they are applied to the measurement of acoustoelastic effects in PMMA materials. Both the surface skimming longitudinal wave and Rayleigh surface wave can be simultaneously excited and measured. With a uniaxial-loaded PMMA sample, both acoustoelastic effects for surface skimming longitudinal wave and Rayleigh waves of PMMA are measured. The acoustoelastic coefficients for both types of surface wave motions are simultaneously determined. The transducer and its measurement method provide a practical way for measuring surface stresses nondestructively. 相似文献
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A methodology for automatic measurement of surface tension of liquid metals is presented. The procedure involves the digitization of a television image of a drop of the liquid metal, image processing to obtain the real coordinates of the drop profile, and a final computation of the drop surface tension by a nonlinear regression technique. The method is faster and more reliable than other classical methods, and yields results that are reproducible and as precise as those obtainable by non-automatic procedures. An important feature of this approach is that it can be used for metallurgical tests to check the quality of an alloy during its production, or to provide surface tension data in non-equilibrium processes. 相似文献
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一种新型非接触位姿检测系统研究 总被引:1,自引:1,他引:1
提出一种基于位置敏感探测器(简称PSD)多光束同步检测技术的位姿检测新方法,采用两个二维PSD从不同角度同时测量出目标物体上多个特征点的二维坐标,然后通过坐标变换计算得到各点的三维空间坐标;根据位姿变化前后的各点空间坐标,采用比较简单的算法计算出目标物体的位姿参数.通过算例验证该方法是可行的;由初步的实验获得目标物体的位姿参数,最大平移误差为1.0574mm,最大旋转误差为0.2851rad,需要通过多种途径进一步提高系统的检测精度. 相似文献
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Reconstructing a free-form surface from 3-dimensional (3D) noisy measurements is a central problem in inspection, statistical quality control, and reverse engineering. We present a new method for the statistical reconstruction of a free-form surface patch based on 3D point cloud data. The surface is represented parametrically, with each of the three Cartesian coordinates (x, y, z) a function of surface coordinates (u, v), a model form compatible with computer-aided-design (CAD) models. This model form also avoids having to choose one Euclidean coordinate (say, z) as a “response” function of the other two coordinate “locations” (say, x and y), as commonly used in previous Euclidean kriging models of manufacturing data. The (u, v) surface coordinates are computed using parameterization algorithms from the manifold learning and computer graphics literature. These are then used as locations in a spatial Gaussian process model that considers correlations between two points on the surface a function of their geodesic distance on the surface, rather than a function of their Euclidean distances over the xy plane. We show how the proposed geodesic Gaussian process (GGP) approach better reconstructs the true surface, filtering the measurement noise, than when using a standard Euclidean kriging model of the “heights”, that is, z(x, y). The methodology is applied to simulated surface data and to a real dataset obtained with a noncontact laser scanner. Supplementary materials are available online. 相似文献