Planarity assessment method for decreasing number of measuring points

Abstract

The invention relates to a planeness assessment method for reducing the number of measuring points, and has the following specific steps: the plane error values at a plurality of point positions on a plane are measured according to the existing planeness measuring method; the probability distribution of the measured plane errors is estimated by the maximum entropy method according to the limited measuring point values; according to the estimated probability distribution, the estimated value of the plane errors between the measuring points is generated at other positions of the measured plane, that is, the measuring points are interpolated; the planeness error assessment methods such as least envelope zone method, least square method or diagonal method are adopted to assesses the planeness error based on the measured value of the planeness error and the estimated value of the plane error at interpolation position; the planeness errors are respectively calculated according to the probability, statistical theory and a plurality of estimated values at interpolation position, and the mean value of the calculated results is taken as the final planeness error assessment value. On the basis of maximum entropy method, the invention uses limited measuring data sample to determine the probability distribution of the measured plane error.

Description

technical field [0001] The invention relates to a method for measuring flatness, in particular to a method for measuring and evaluating flatness errors. Background technique [0002] Flatness is one of the main items of shape tolerance, and the measurement and evaluation of flatness error is of great significance in the measurement of geometric quantities. According to the national standard for shape and position tolerance, the flatness error refers to the variation of the measured surface to the ideal plane, and the orientation of the ideal plane should meet the minimum condition, that is, its orientation should make the maximum variation of the measured surface to the ideal plane be minimum. In the evaluation of flatness error, the number of measurement points for flatness error has a great influence on the evaluation result. Since the position of the surface to be measured is represented by several measurement points, the actual error value is often underestimated due t...

AI Technical Summary

Problems solved by technology

Since the position of the surface to be measured is represented by several measurement points, the actual error value is often underestimated due to the limitation of the number of sampling points when using measurement sampling points to evaluate the error

On the other hand, limited by the measurement time, it is impossible to have many flatness error measurement points

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