Process for conformal processing of cylindrical shell inner weld seam

Patent metadata

Field	Value
Publication number	US-12472575-B2
Application number	US-202217981126-A
Country	US
Kind code	B2
Filing date	Nov 4, 2022
Priority date	Dec 16, 2021
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

A process for conformal processing of a cylindrical shell inner weld seam by a special mobile robot includes using a laser scanner to scan a cylindrical shell inner weld seam to obtain point cloud data of a contour of a weld seam area first. Weld seam feature identification is carried out to each generatrix, and misidentified generatrices are filtered out to obtain weld seam left and right boundaries. An ideal weld seam processing contour is generated conformally according to the appearance of the weld seam area, weld seam coarse grinding is carried out after correction and compensation, and weld seam contour information after coarse grinding is obtained by scanning after the coarse grinding is completed. Process parameters of the grinding are controlled according to an actual weld seam contour, and weld seam fine grinding is carried out to obtain a smooth weld seam contour.

First claim

The invention claimed is:

1 . A method for conformal processing of a cylindrical shell inner weld seam by a special mobile robot, wherein in the method, a weld seam contour is scanned and measured to obtain point cloud data of a contour of a weld seam area first; then weld seam feature identification is carried out to each generatrix, and misidentified generatrices are filtered out to obtain weld seam left and right boundaries; an ideal weld seam processing contour is generated conformally according to the appearance of the weld seam area, and weld seam coarse grinding is carried out after correction and compensation; weld seam contour information after coarse grinding is obtained by scanning again after the coarse grinding is completed; process parameters of the grinding are controlled according to an actual weld seam contour, weld seam fine grinding is carried out, and shape of an inner weld seam contour is trimmed to complete the conformal processing; and the method comprises the following specific steps:
step 1: first weld seam contour measurement and feature identification putting a robot in a cylindrical shell, stopping the robot after the robot is judged to reach a weld seam according to a real-time image collected by a wide-angle camera, and using a laser scanner to measure an annular weld seam area in the cylindrical shell; matching measurement data of the laser scanner with position information of each kinematic axis of a three-axis drive mechanism to obtain point cloud data of a contour of a cylindrical shell inner weld seam area; representing the obtained point cloud data as N generatrices (K 1 , K 2 , . . . K N ) in an X-R plane in a cylindrical coordinate system (X-R-A coordinate system); then carrying out weld seam feature identification to each generatrix in the X-R plane; taking the M th generatrix K M as an example, selecting the leftmost m points [(x 1 , r 1 ), (x 2 , r 2 ) . . . (x m , r m )] within the range of the generatrix as initial points, and fitting a left inner wall contour line according to formula (1); starting from the (u=m+1) th leftmost point, calculating a distance d u l from each point to the left inner wall contour line in sequence from left to right according to formula (2);

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where, (x i , r i ) is a coordinate of a point involved in fitting, and n is the number of points involved in fitting; x is an x average value of the points involved in fitting; r is an r average value of the points involved in fitting; and r=ax+b is the fitted inner wall contour line;

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Assignees

• Univ Dalian Tech

Inventors

• Li Te
• Lan Tian
• Liu Haibo
• Ge Yuhang
• Bo Qile
• Liu Kuo
• Liu Xingjian
• Li Xu
• Wang Yongqing

Classifications

• B24B27/033

  for grinding a surface for cleaning purposes, e.g. for descaling or for grinding off flaws in the surface · CPC title

• B24B49/12

  involving optical means · CPC title

• B24B27/0076

  grinding machines comprising two or more grinding tools · CPC title

• B24B27/0038

  with the grinding tool mounted at the end of a set of bars · CPC title

• B24B51/00

  Arrangements for automatic control of a series of individual steps in grinding a workpiece (if applicable to other machine tools, G05B takes precedence) · CPC title