HIGH EFFICIENCY COORDINATE SYSTEM ALIGNMENT METHOD FOR TURBINE BLADE MEASURING SYSTEM

- The problem of coordinate system alignment must be solved first for the 3D measurement of complex surfaces like turbine blades. Coordinate system alignment is an important prerequisite for path planning and measurement data error analysis in the subsequent measurement process. Due to the complex geometric characteristics of turbine blades, the traditional 3-2-1 method cannot guarantee the accuracy, efficiency and stability of alignment. Therefore, based on the point laser non-contact three-coordinate measuring system, this paper proposes a practical two-step alignment method after the analysis of the advantages and disadvantages of the existing alignment technologies. The proposed method divides the alignment process of complex surface coordinate system into two parts: rough alignment and precise alignment. Rough alignment selects feature points according to local measurement results, and calculates the initial transformation matrix between coordinate systems. On the basis of rough configuration, the improved iterative nearest point algorithm is used to calculate the precise transformation matrix to achieve accurate alignment. The experimental results show that the two-step alignment method proposed in this paper effectively solves the efficiency and accuracy problems of alignment, and has a good robustness.