基于单缝衍射原理的圆度误差测量方法

提出了一种全新的圆度误差光学自动测量方法.新方法基于单缝衍射原理,利用工件的圆度误差来改变衍射单缝的宽度,进而改变衍射条纹的间距.在测量单缝衍射中央明纹的宽度时,提出了用最小二乘法对测量到的衍射图像的光强分布进行二次曲线拟合,并由拟合得到的数学表达式,确定衍射暗条纹的精确位置.由导出的工件圆度误差与单缝衍射中央明纹宽度之间的关系,用最小二乘法对工件的圆度误差进行了评定.测量结果表明,新的圆度误差测量方法是可行的,圆度误差的相对不确定度小于1.4%,并且测量系统具有操作方便、精度高的优点,新方法也可应用于锥角、直线度误差等其它几何量的精密测量中.

Method of measuring roundness error based on slit diffraction

A new optical method for automatic measurement of roundness error was presented based on the diffraction principle of a slit.In measurement system,the slit width was changed with the workpiece roundness error,so the distances of diffraction fringes were altered.In order to compute the width of the center bright stripe according to the accurate position of diffraction dark fringes,the least square method was used to fit quadratic curves of the intensity distribution.With the least square method,the roundness error could be evaluated by the relationship between workpiece roundness error and the width of the center bright stripe.The measuring result proves the feasibility of the new method.The relative uncertainty of the workpiece roundness error is less than 1.4%.The measuring system is easy to operate and has high measuring accuracy.This method can be applied to measure the cone angle error and the alignment error,etc.