Method for utilizing frequency domain method to make defference measurement of accurate reconfiguration

Abstract

The method for making accurate restructure of difference measurement by using frequency domain method is characterized by that according to the difference value obtained by measuring two different separation distances or shearing quantities of measured object, making two groups of difference values undergo the process of cycle continuation and utilizing Fourier obverse and inverse transformation to obtain two initial evaluation curves, then calculating the difference value of ratio of zero modulation error and correspondent sensor separation distance or shearing quantity and combining two initial evaluation curves and eliminating the influence of zero modulation error to obtain the evaluation curve of measured parameter, then removing the linearity tendency in the evaluation curve to obtain one accurate evaluation curve having no theoretical error so as to implement the accurate restructure of measured parameter.

Description

Technical field: [0001] The invention relates to the technical field of detection applications, in particular to a detection method for reconstructing the original measured parameters according to the differential measurement values ​​of the measured parameters, including the straightness, flatness, cylindricity, and free-form surface of precision and ultra-precision workpiece surfaces. Surface shape detection and wavefront reconstruction for transverse shear interference. Background technique: [0002] In ultra-precision machining, in order to detect the straightness, cylindricity, flatness and surface accuracy of the surface of the workpiece, the multi-probe scanning method is often used. This method uses the displacement probe (commonly used non-contact sensors such as eddy current or Capacitance, etc.) or angle detectors (such as autocollimators, etc.) are installed on the slide plate and move linearly along the measured contour of the workpiece, or the sensor is fixed, ...

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Problems solved by technology

Thus injecting new vitality into the transverse shear wavefront interference method, this method can reconstruct various surfaces (including periodic, non-periodic, smooth and non-smooth surfaces, etc.) without any "prior" knowledge, On this basis, an ESAD (Extended Shear Angle Difference) surface topography detection device has also been developed, but this method still has some shortcomings, such as it only works when the size of the workpiece is equal to the multiple of the shear amount. Only when the situation is the case, can the reconstruction be done accurately, otherwise smooth continuation is required, which will have some impact on the reconstruction accuracy, and the relationship between the sensor zeroing errors during the two shear measurements has not yet been calculated, so this This method also has a large error when it is used for displacement sensor measurement such as straightness, cylindricity, flatness, etc., so it needs to be further expanded and improved

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