| Aircraft manufacturing is a complex system engineering.The assembly accuracy of the final products determines whether the aircraft can meet the design requirements.The wing is one of the key components of the whole aircraft manufacturing process due to its complicated structure,high aerodynamic shape requirements and high assembly precision requirements.The digital measurement system is used to construct a digital assembly and measurement system for the large-scale aircraft wing assembly.Through the digital transmission,the precise positioning of the wing assembly components can be achieved,which can effectively improve the wing assembly quality and production efficiency.In this paper,the digital assembly of a certain type of wing is taken as the research object.An in-depth study on how to improve the accuracy of the digital measurement system will be taken in order to construct a large-scale wing digital measurement system,based on the principle analysis of the measurement system,the construction of the measurement field,the analysis of the system error and the correction method.The main research contents of this paper are as follows:1 The field assembly coordinate system,aircraft coordinate system,measurement coordinate system,numerical control positioning coordinate system,numerical control machine coordinate system,etc.in the digital measurement system are defined,based on the measurement principle of laser tracker.Describe the realization way to unite all the coordinate systems using the method of SVD.2)This paper analyzes the measurement requirements of large-scale wing assembly system,and summarizes the layout basis of laser tracker and the selection basis of common reference points,and determines the layout scheme of laser tracker and measurement system of this project.3)This paper classifies the errors and sources in the digital measurement field,summarizes the correction methods of instrument measurement errors,environmental factors,operation errors and measured object errors,analyzes the influence of thermal deformation on the measurement system errors,and corrects the errors caused by thermal deformation by calculating the thermal expansion compensation coefficient in different directions,setting position compensation and compensation measurement mechanism.The accuracy of the measurement system of this project has been achieved at ± 0.05mm.The measurement field of wing assembly system is constructed by using the measurement system and digital measurement field construction software,and the accuracy of the measurement field is verified by positioning the large parts of the wing of a certain aircraft. |
