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Measuring and calculating method of profile line part without datum

A calculation method and profile technology, applied in the field of geometric measurement, to achieve the effect of real measurement results and stable and reliable operation

Active Publication Date: 2012-06-06
SHENYANG LIMING AERO-ENGINE GROUP CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because the shape of the contour is complex and not a single straight line or arc, and the maximum variation between the measured actual element and its ideal element must be minimized during the evaluation, calculation is a difficult problem in the evaluation of contour degree.

Method used

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  • Measuring and calculating method of profile line part without datum
  • Measuring and calculating method of profile line part without datum
  • Measuring and calculating method of profile line part without datum

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Experimental program
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Embodiment 1

[0060] The present invention provides a method for measuring and calculating parts without reference profile, which is characterized in that: the method for measuring and calculating parts without reference profile is as follows:

[0061] First, given the initial translation value (Δx, Δy) and rotation angle Δθ of the scanned data point, the default initial value is zero. If the scanned data point deviates greatly from the theoretical profile, the initial value can also be given manually; then, for The scanned data points are translated and rotated, and the minimum distance d between the moved scanned data points and the theoretical surface is calculated one by one i And eliminate gross error points; secondly, use the improved Levenberg-Marquardt algorithm to iteratively solve the least squares fitting value of the theoretical type surface scanning data points; finally, evaluate the scanning data and output the evaluation results.

[0062] Geometry is composed of straight line...

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Abstract

A measuring and calculating method of a profile line part without datum comprises the following steps: firstly, giving an initial translation value (Delta x, Delta y) and a rotation angle Delta theta of a scanning data point, defaulting an initial value to be zero, if the scanning data point has a large deviation with a theory type surface, manually giving the initial value; then, carrying out translation and rotation to the scanning data point and successively calculating a minimum distance di between the scanning data point and the theory type surface and rejecting a thick error point; secondly, using an improved Levenberg-Marquardt algorithm to perform an iterative solution to a least-squares fitting value of the theory type face to the scanning data point; finally, evaluating the scanning data and outputting an evaluation result. By using the measuring and calculating method of the profile line part without the datum disclosed in the invention, a concrete number can be given during evaluating the profile line, precision of the evaluation result is high and repeatability is good. A program writing mode is used to automatically realize calculation during calculating so as to improve batch test efficiency.

Description

technical field [0001] The invention relates to a measurement method for geometric quantities, and in particular provides a measurement and calculation method for parts without a reference profile. Background technique [0002] Line profile and surface profile are two special form and position tolerance items. The national standard stipulates the other 12 geometrical tolerances among the 14 geometrical tolerances, which can be clearly classified into geometrical tolerances (four items) and positional tolerances (eight items), while line and surface profile tolerances have both shape and position tolerances. Tolerance and Position Tolerance Hu properties. However, because the shape of the contour is complex and not a single straight line or arc, and the maximum variation of the measured actual element to its ideal element must be minimized during the evaluation, the calculation is a difficult problem in the evaluation of the contour degree. [0003] For line profile toleran...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B21/20
Inventor 张露单纯利王东李景尧
Owner SHENYANG LIMING AERO-ENGINE GROUP CORPORATION
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