Method for establishing contour baseline in two-dimension surface roughness assessment

Abstract

There is a sort of method which establishes the contour baseline in the assessment of the two-dimension surface roughness, it is characterized in that: it uses gray rolling model to progress the gray modeling to a sampled data which is in the original contour of the sampling length, thereby obtain the model curve of the contour. And make the corresponding model curve of the sampled data which is in the assessing length to progress colligation, thereby obtain a slick curve of the contour, and make this curve to become the contour baseline which is in the assessment of the roughness. The original data of the contour does not obey the classical distribution, and in the assessing course it does not loss original data. It obtains the gray baseline in the whole assessing length, and does not wipe off the error of the shape in advance, the gray is slick and natural in the whole assessing length, and it is close to the Gauss baseline.

Description

technical field [0001] The invention relates to a method for establishing a contour reference line in two-dimensional surface roughness evaluation. Background technique [0002] In the evaluation of two-dimensional surface roughness, the establishment of contour reference line is a key link. Commonly used methods for establishing the contour reference line include the least-squares median line and the arithmetic mean median line (see: Li Zhu, editor-in-chief, "Interchangeability and Measurement Technology", Beijing: Higher Education Press, 2004.). In both methods, the contour reference line is established by regression analysis, which is an approximate fit to the ideal reference line. Although the evaluation of surface roughness by these two methods is simple, there are some inherent disadvantages: (1) From the perspective of surface processing properties, the reference line of the contour is a smooth curve, but within a certain evaluation length , the contour reference li...

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Problems solved by technology

Although the evaluation of surface roughness by these two methods is simple, there are some inherent disadvantages: (1) From the perspective of surface processing properties, the reference line of the contour is a smooth curve, but within a certain evaluation length , the contour reference line in different sampling lengths may appear discontinuous at the junction, resulting in the contour reference line in the entire evaluation length may become an unsmooth broken line; (2) use this reference line to evaluate the surface roughness, and the evaluation results are extremely The ground depends on the sampling length, too long or too short a sampling length will distort the surface roughness evaluation

The fractal method mainly has the following two shortcomings: one is that not all actual surfaces have fractal characteristics, and the fractal method is not applicable to surfaces without fractal characteristics; the other is that the existing fractal mathematical model does not consider the surface features, and there is no method to uniquely determine the fractal dimension

The disadvantage is that in the process of solving the baseline, there is randomness in the determination of the wavelet decomposition level and the selection of the baseline, which leads to a certain degree of uncertainty in the roughness evaluation results using the wavelet baseline.

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