Quantitatively evaluate the cylindricity of Large size pipe fitting via laser displacement sensor and Digital twin technology

Abstract

The rapid development of intelligent detection technology guarantees accuracy in the assembly process. Aiming to solve the quantitative inspection of the cylindricity of Large size pipe fitting, this paper presents an online method technology using a laser sensor and Digital twin technology. The detection system comprises visual positioning, servo drive, and laser displacement sensor information acquisition systems. After positioning by the machine vision camera system, the servo system and laser displacement sensor scan the large-size pipe fitting layer by layer and establish the information interaction between physical space and virtual space through digital twinning technology. The digital twin scatters information model was found to calculate the maximum tangent circle and minimum peripheral circle, fitting the curve area of the closed point cloud layer by layer. And the least square method was used to calculate the center of the layered circle. The radial deviation of pipe fitting was evaluated comprehensively. The system makes a linear fitting of the center of the most miniature square circle of each layer, compares its deflection Angle with the solid center line, and calculates the center line deviation of the hole. Finally, the precision of the proposed method was validated by varying experiments. The cylindricity measurement of pipe fittings with an inner diameter of 300mm and height of 270mm was carried out by a pair of C-shaped semicircles fixed by the radial assembly. The cylindricity of the pipe fitting is 0.2372mm.