Error analysis study of 3D laser scanning technology in large space grid structure measurement

Construction error is an important factor affecting the quality and safety of large space grid structures. For welded ball nodes, the traditional measurement methods have problems such as low efficiency, target paper pasting error, and inability to obtain ball center coordinates. The application of 3D scanning technology and point cloud inverse modeling technology can efficiently and comprehensively obtain the coordinates of the welded ball center of the structure, and compare with the theoretical ball center coordinates to realize the construction error analysis. Taking the new seaport passenger hub project in Haikou as an example, the point cloud data obtained from the Leica 3D scanner was imported into Cyclone software for stitching, coordinate transformation and noise reduction to obtain the point cloud model, and the least squares method, RANSAC method and Cyclone's own function were used to fit the welded ball to obtain the ball center coordinates and compare with the theoretical ball center coordinates to achieve the construction error analysis. The results show that: the 3D scanning technology is used to obtain the coordinates of the welded ball. The results show that the point cloud model obtained based on 3D scanning technology has high accuracy and can be combined with two algorithms and Cyclone software to achieve batch cutting and fitting of welded balls and visualization of individual balls according to the actual needs when doing construction error analysis. This method not only provides a new idea for construction error analysis of large space grid structure by scanning and fitting the structure at different stages of construction, but also can guide the site construction to correct the deviation and improve the project quality.