基于数字散斑技术的静刚度测量仪

Static Stiffness Measuring Instrument Based on Digital Speckle Technique

静刚度是起重机械的一项重要安全指标,其主要测量参数为起重机大梁在空载与加指定载荷情况下大梁跨中挠度数值。在加载前后,大梁底部边界灰度特征保持稳定,利用数字散斑相关算法可以准确计算像平面中大梁边界移动量。在已知光学成像系统参数的情况下,由像平面中位移可精确计算大梁物面实际移动量。结合斜轴成像特点搭建了静刚度测量系统,并对斜轴光路系统测量误差进行分析,优化了子区位置与子区大小的选择。利用该系统对模拟大梁移动量进行测量,误差在0.2 mm以内。在30 m远处对起重机大梁进行静刚度实测,测量结果与对照方法一致,表明该方法能够满足现场起重机大梁静刚度测量要求。

Static stiffness is an important safety index of hoisting machinery,and its main measurement parameter is the deflection value of the crane girder in the case of no-load and specified load. Before and after loading,the gray features of the bottom boundary of the beam remain stable,and the displacement of the beam boundary in the image plane can be accurately calculated by using the digital speckle correlation algorithm. When the parameters of the optical imaging system are known,the actual displacement of the beam can be accurately calculated from the displacement in the image plane.Combined with the characteristics of oblique axis imaging,the static stiffness measurement system is built,and the measurement error of the oblique axis optical system is analyzed,and the selection of sub region location and sub region size is optimized. The system is used to measure the movement of the simulated girder,and the error is within 0.2 mm. The static stiffness of the crane girder is measured at a distance of 30 m,and the measurement results are consistent with those of the control method,which indicates that the method could meet the requirements of the static stiffness measurement of the crane girder.