Key Technology Research On Large-scale Laser Tracking Measurement

In the field of aerospace, coordinate measuring technology, which usually wasused in the assembly process measuring and assembly measuring, has been widely usedin large-scale geometric measurement. With the development of the digital productdefinition technology, the coordinate measuring technology based on three-dimensionalmodel has been widely used in industrial measurement, which greatly improvesproduction efficiency. However, there are many urgent problems need to be solved,coordinate measurement information expansion and extraction based onthree-dimensional model is an effective way to achieve consistency of design andmeasurement process information. Measurement uncertainty has important engineeringsignificance under GPS geometrical product specifications, which is currently one of thehotspots. The characteristics of large-scale workpiece also cause a significant impact onthe measurement process. In this paper, some studies have been done about the fouraspects, main content and the results are as follows:(1)Three-dimensional coordinate measuring expansion model is established andmeasurement program library is build. Coordinate measuring information appended bydesigner is extended in PRO/E and CATIA.(2)The size information, geometric tolerances information and measurementinformation contained in the three-dimensional model is extracted, which can be used inmeasuring process and achieve the consistency of design and measurement process.(3)A detailed analysis of the sources of uncertainty is achieved in laser measuringprocess, concentricity and perpendicularity are used to analyze the sampling strategyand measurement definition how to influence the uncertainty by using the Monte-Carlomethod. Some suggestions are given at last.(4)Accounting for the impact of gravity-induced deformation to actual measuringprocess, the deformation of large-scale workpiece under its own gravity is studied. PPRpipe is used as an experimental subject to analyze the gravity-induced deformation.Software compensation is achieved for the deformation.