The Development of in Situ Measurement Technique for Ship Plate Manufacturing

Processing steel plate is the major step during the ship construction processes. In order to maintain more accurate control of the ship plate bending and reduce technical training time and cost, we developed a computer program for calculating the difference between the geometry of the manufactured curve plate with the design blue print. In the developed program, the coordinate rotation matrix and Euler angles (Deakin in Surv. Land Inf. Sys. 58:223–234, [1]; Lehmann in J. Geodesy 88:1117–1130, [2]; Shimizu in Evaluation of Three Dimensional Coordinate Measuring Methods for Production of Ship Hull Blocks. Kitakyushu, Japan, pp. 348–351 [3]) are applied to unify the coordinate system between the measured 3D data with the ship coordinate system. The program is written under the MATLAB coding environment. In our research, the most time consuming task is to determine which sets of rotation axes that can be used to transform the measuring coordinate to the design coordinate with the minimum error. Therefore, the least squares method is used to find the optimum Euler angle based on the minimization of error between the measured and design data. We have built an iterative scheme to search the most suitable set of rotation axes and the Euler angles, which spends about 30 s or less, and it has been tested for the in situ application. The program has the potential to speed up the plate processing time and aid the automated manufacturing capability of the ship yard.