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《光学学报》2015,(7)
扫描干涉场曝光系统中的干涉条纹周期是相位锁定系统的重要参数,为精确测量干涉条纹周期,根据扫描干涉场曝光系统的特点提出了分束棱镜移动测量干涉条纹周期的方法,根据高斯光束传播理论,分析了该方法的理论误差;提出了周期计数法对周期测量数据进行计算。为降低对系统二维工作台运行及稳定精度的要求,提出了小行程高精度位移台辅助测量周期的方法,并进行了相关实验验证。结果表明:小行程位移台辅助周期测量方法在原理上可行,对于干涉条纹线密度1800 line/mm的系统参数,小行程位移台辅助周期测量的重复性可达到1.08×10-5(σ值),曝光实验的实测值与理论模型之间一致性较好,验证了该周期测量方法的可行性。 相似文献
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介绍了基于几何莫尔条纹原理和衍射干涉原理的两种光栅精密位移测量系统及各自的特点。综述了国内外对光栅干涉式精密位移测量系统的研究进展,总结了系统存在的关键问题及发展趋势。光栅干涉式精密位移测量系统的优点是对环境要求小,测量分辨率和精度较高,结构紧凑,成本低。该系统需要解决的问题包括提高光栅以及光学元器件制造和安装精度;寻求一种更高精度的检测手段对光栅位移测量系统进行标定等。光栅干涉式精密位移测量系统的发展方向为更高测量分辨率和精度,大量程、多维度测量以及尺寸小巧。该系统在现代工业加工精密制造领域将具有更广阔的应用前景。 相似文献
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数字图像相关中基于位移场局部最小二乘拟合的全场应变测量 总被引:10,自引:0,他引:10
为了从含噪声的位移场中计算得到可靠的应变场,提出一种基于位移场局部最小二乘拟合的全场应变求解方法。介绍了数字图像相关方法的原理,阐述了基于位移场局部最小二乘拟合的全场应变求解方法,并讨论了计算区域边界、孔洞及裂纹附近区域等情况下的应变计算。对均匀变形和中心带圆孔的薄铝板拉伸实验的计算结果表明,该方法能有效地从原始位移场数据中提取全场应变信息。在均匀变形情况下应选择大的应变计算窗口,计算结果更逼近真值;在非均匀变形情况下,如果位移场中包含较强的噪声,则应选择较大的应变计算窗口,而位移场精度很高时可选择更小的应变计算窗口。 相似文献
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Lens distortion practically presents in optical imaging system using in two-dimensional digital speckle correlation measurement (2D-DSCM) system, and gives rise to additional errors in the displacement and strain measurement. Camera calibration procedure is performed to obtain the coefficients of radial distortion and tangential distortion. The corrected displacement fields can be calculated using the distortion coefficient. The influence of distortion on displacement and strain measurement errors in experiment is further discussed. The three-point bending test result shows that the camera lens calibration method can effectively eliminate the effect of lens distortion and improve displacement and strain measurement accuracy. 相似文献
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传统的动态位移测量方法属于接触式测量,常用应变式位移计直接测量结构变形,其测量精度往往取决于位移计安装情况,且测量的电信号容易受到试验环境的影响。随着光学测量技术的不断发展,基于双目立体视觉和数字图像处理技术的光学测量方法已开始应用于位移测量。为了解决传统动态位移测量的精度问题和环境对信号的干扰问题,将双目立体视觉技术应用到三层钢框架结构的振动台试验中,对结构在地震作用下的位移进行测量。研究结果表明:从位移时程和位移偏差率两方面同传统测量方法进行对比分析,光学测量方法减少了2.0 s~3.5 s的相对滞后时间,增强数据可靠性;位移偏差率最大为7.03%,最小为0.02%,均在测量误差允许范围之内,验证了光学测量位移方法在结构抗震试验中的可行性及优越性。 相似文献
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The digital ultrasonic speckle phase-shifting method (USPM), which is introduced in this paper, can be applied to the measurement of small displacement that is smaller than speckle size at the test point compared to traditional ultrasonic speckle correlation method (USCM). Using USPM, a digital ultrasonic reference signal is introduced to interfere with the ultrasonic speckle signal, which is picked up at the test point on an object surface and is referred to as the object signal. As the phase of the reference signal is shifted several times using the software and then they superimpose with the object signal respectively, the phase of the object signal can be calculated according to the intensities of the superimposed signals. If the object surface moves a small distance, the phase variation of the object speckle can be detected by the same process. As a result, the displacement of the object surface can be measured. Based on the feature of ultrasonic speckles, inner surface displacement of an object can be measured using this proposed method. In this case, the effect of outer surface roughness to the measurement accuracy of USPM is examined experimentally. The experimental results show that the measurement is successful when the displacement is smaller than half of the speckle size at the test point and the roughness parameter Ra of the outer surface of the specimen is less than about 5.47 μm. 相似文献
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为了验证ITER磁体支撑结构的可靠性,建立了多维加载测试平台对支撑部件进行机械性能检测。测量控制系统由7台EDC控制器、计算机系统、16通道准动态应变仪、25只位移传感器、7套油缸中的负荷和位移传感器组成。基于可编程语言,利用EDC220数字控制器实现了多通道协调加载的测量和控制过程,完成了7套双油缸高精度同步控制实验。针对典型的加载工况进行工程测试。结果表明,测控系统设计合理,控制系统可靠,能满足下一步的实验要求。 相似文献
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为了验证ITER 磁体支撑结构的可靠性,建立了多维加载测试平台对支撑部件进行机械性能检测。测量控制系统由7 台EDC 控制器、计算机系统、16 通道准动态应变仪、25 只位移传感器、7 套油缸中的负荷和位移传感器组成。基于可编程语言,利用EDC220 数字控制器实现了多通道协调加载的测量和控制过程,完成了 7 套双油缸高精度同步控制实验。针对典型的加载工况进行工程测试。结果表明,测控系统设计合理,控制系统可靠,能满足下一步的实验要求。 相似文献
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In this work, we describe a fiber Bragg grating (FBG) sensing system using two wavelength-matched FBG sensors for static and dynamic strain measurement. A cascaded long-period fiber grating (CLPG)-based demodulation technique has been used to interrogate the two wavelength-matched FBG sensors. Experimental results of static strain measurement show that the proposed system has a strain resolution of 1 με. This system has also been used for dynamic strain measurement. An eddy current displacement meter-based system has been used as a comparison measurement. Experimental results of dynamic strain measurement have proved that the FBG sensing system has a good performance in the measurement of dynamic strain. The results of static and dynamic strain measurement indicate that the sensing system using two wavelength-matched FBG sensors is superior to the single FBG sensor system. 相似文献