Coordinate Measurement Definition Extension And Uncertainty Evaluation Based On 3D Model

In the manufacturing process of aerospace products, coordinate measuring method has become the primary means of quality control. It is widely used in online or offline testing of part machining, parts assembly process testing, machine assembly testing and so on. Due to this method, it greatly improves production efficiency, reduces the cycle of product update.With the develop of product digital definition, the three-dimensional mathematical model has gradually become a unique data source of the manufacturing process, coordinate measuring technology based on three-dimensional mathematical model has become the focus of industrial measurement technology.There are many pressing problems in the coordinate measuring technology based on three-dimensional mathematical model, where the two key problems are the information lack of three-dimensional model coordinate measurement and the quality evaluation of measurement results. In this paper, it has deeply studied the relevant technology of these two aspects. The main contents are as follows.(1)This article has analyzed the general process of coordinate measurement, established the coordinates measurement information model of the geometrical product specification and verification based on the new generation, proposed the overall plan of the three-dimensional coordinate measurement information expansion and uncertainty evaluation.(2)As to the information input problem of the 3D model coordinate measuring, the article has analyzed the needs of coordinate measuring extensions, proposed the extension requirements and contents of the 3D model testing information, studied the implementation of the expansion contents, and achieved coordinate measuring information expansion in Pro/E.(3)As to the uncertainty of coordinate measurement, the article has deeply analyzed the contributing factors of measurement uncertainty, established the basic processes of evaluating the coordinate measurement uncertainty based on Monte-Carlo method. Finally, two examples, evaluation of plane distance and straightness measurement, are taken to validate the uncertainty, which are brought by the coordinate measuring definition and evaluating algorithm.