A Method for Measuring the Inclination of Forgings Based on an Improved Optimization Algorithm for Fitting Ellipses

Dimension measurement method of ring forgings based on laser scanning and multiple regression filtering algorithm

“…In addition to the isolated point outliers described in section 3.1, clusters of continuous outliers were observed due to the errors caused by the excessive reflectivity of the measured workpiece surface and the location of this cluster of outliers was not fixed, so these clusters of outliers were randomly filtered using the randomization idea in [12]. Since the coordinates of the points in the Y-direction are linear in period, only the coordinates in the X-direction need to be processed.…”

“…In figure 10, the points marked in black are the standard deviation of the residuals of the outlier matches, and there is a clear bulge in the values in this section compared to the normal scan section. The outlier cluster region was determined according to the criterion in [12], and the residual value of each fitting result relative to the measured point cloud was calculated. The residual matrix was then constructed, the residual value corresponding to each training was found for each point, and its standard deviation was calculated.…”

“…The method proposed in this paper was used to measure the dimensions of a standard part with an elliptical annular outer contour, whose long axis length is 269.24 mm and short axis length is 263.87 mm. The ellipse was fitted to the point cloud data by combining the method proposed in the literature [12]. To verify the feasibility of the method proposed in this paper for the external dimension measurement of elliptical ring forgings, the long axis of the measured ellipse is denoted by a and the short axis is denoted by b.…”

“…For measuring forging geometry based on laser ranging method, we have carried out in-depth research: We proposed a concentricity measurement method based on laser ranging principle, and designed a concentricity measurement system for concentricity measurement of piercing rod and forging parts. Results suggested the measurement error of concentricity deviation was less than 0.5 mm, and hence the proposed concentricity method is suitable for concentricity measurement of forging and piercing, which can improve the operation accuracy of upsetting or piercing [10]; An online roundness measurement method based on laser ranging principle and improved particle swarm optimization is proposed, which can achieve online measurement of roundness during rolling of large ring parts with the help of ring rotation during rolling, and the measurement accuracy meets the actual engineering requirements avoiding the influence of ring size on roundness measurement [11]; A method of forging inclination measurement based on ellipse fitting optimization algorithm was proposed, in which the threedimensional linear equation of the central axis of the forging was obtained according to the centroid of the long axis of the ellipse in the vertical direction, and the measurement error of the inclination angle of the forging was less than 0.05 • according to the linear equation [12]. However, the laser distance measurement method is only suitable for dimensional measurement in the case of relative motion between the measured forging and the laser displacement sensor, and it is difficult to achieve forging contour measurement under the conditions of fixed forgings and complex measurement environment.…”

Forging measurement using passive stereo vision

“…This technology is not significantly influenced by the effects present in the industrial environment [11][12][13][14] . Various rangefinders based on this principle are also used to adjust to forging position under the forging press 15,16 . However, the disadvantages of laser scanning are the measurement time, which can be up to several minutes (depending on the measurement volume and point cloud density), and the accuracy achieved, which is in the millimeter range.…”