Research On The Key Techniques Of Precision Metrology For Large-Scale Equipments Based On Laser Tracker

With the development of aerospace,ships,heavy industry and a variety of scientific research infrastructure construction etc,more and more industrial equipments manufacturing were confronted with various problems,such as large-scale,high precision requirements,complex structure of the measured characteristics and so on.High precision detection and positioning of large-scale complex equipment has become a major bottleneck in the development and improvement of large-scale equipment.The traditional measurement method has been unable to meet the requirements of this large-scale industrial manufacturing,both in terms of accuracy,range and efficiency.Therefore,large-scale precision three-dimensional coordinate measurement technology has become an urgent problem to be solved.Laser tracker is a high-precision mobile measurement equipment,mainly using the interference distance measurement technology and the target tracking technology based on position detection device to achieve real-time tracking of space targets and high-precision positioning,easy operation,flexible facilities,the strong on-site applicability,known as "portable CMM",it can meet the large equipment installation and manufacture of large size,high precision requirements.Therefore,this paper relies on a large-scale scientific research infrastructure equipment installation measurement projects,laser tracker in large-scale precision measurement of some of the key technologies were discussed,the main work is as follows:Firstly,the working basic principle of the laser tracker technology and the composition of the system and several key technologies are introduced in detail.The factors that influence the measurement accuracy of the laser tracker are analyzed.The single point precision evaluation method is studied and the Monte Carlo simulation and visual error ellipsoid and other numerical simulation methods to accurately express the point error.The key technologies and methods of 3D precision control network measurement principle and data processing based on laser tracker are studied.The adjustment theory of three-dimensional corner net and the condition of solving are discussed.According to the precision characteristics of laser tracker,the expression of empirical weighting is given,and the fixed weight method of Helmert variance component estimation is deduced.The principle of Unified Spatial Metrology Network(USMN)is expounded,and the accuracy and advantages and disadvantages of several adjustment methods are compared and analyzed.Laser tracker station-transfer measurement technology is the essence of three-dimensional coordinate transformation problem.Aiming at the transformation of large rotation angle,the realization process of quaternion,SVD decomposition,Rodrigue matrix and so on is summarized.Considering the random error of common coordinate of two sets of coordinate systems,we propose to adopt the multiple integral least squares model(MTLS)based on EIV model to solve the coordinate transformation parameters of laser tracker transfer station.The factors influencing the measurement accuracy of the transfer station are analyzed,and the error distribution of the two-dimensional and three-dimensional coordinate transformation is deduced based on the least squares principle.The influence of the measurement error and the common point layout is anablyzed emphatically.Finally,the application and realization in the precision measurement of large-scale equipment based on laser tracker are studied,and an effective measurement scheme is put forward.