Research On 3D Coordinate Measuring System Based On Laser Tracking Absolute Length Measurement Multilateral Method

In the manufacturing and assembly of large high-end equipment such as aircraft manufacturing,antenna mounting and other aerospace fields and other fields,there is an urgent need for advanced measurement techniques and measures with a large measurement range and high measurement accuracy.Although the traditional instrument systems such as theodolites and laser tracker satisfy the requirements of large space measurement and are widely used,the larger angle error of the instrument limits the further improvement of the measurement accuracy of their space coordinates and can not meet the requirements of higher precision.However,the multi-lateral coordinate measuring technique only uses the distance(length)information to achieve spatial coordinate measurement through multilateral constraints.In particular,the laser-based absolute measurement of the length of the polygon coordinate measurement technology,eliminating the relatively large relative angle error information,using only the laser interferometry based on the high-precision distance measurement information,so theoretically can achieve high coordinate measurement accuracy.At the same time using advanced ADM laser absolute ranging technology to overcome the application of the traditional relative distance measurement limitations.Not only meet the large size,high-precision measurement needs,but also make the measurement process simple and efficient,with broad application prospects.This dissertation focuses on the research of the coordinate measuring technique based on laser tracked absolute length measurement of polygons.The main work includes:1.In this paper,several commonly used large-size coordinate measuring systems are compared and analyzed.The status quo of the development of the multi-coordinate coordinate measuring technique with laser tracking is introduced.The content of the dissertation is clarified.2.The measurement principle of laser tracker and two different laser ranging modes are studied.Based on the principle of multi-station laser tracker network for coordinate measurement of multi-edge method,the principle of three-edge measurement is deduced to realize four stations Mathematical model of laser tracking coordinate measurement.3.The self-calibration model of the multi-lateral measurement system based on absolute laser length measurement is studied.Based on the adjustment theory and L_M algorithm,a residual model is established and the parameters are optimized and solved.4.The optimal placement method of four-station laser tracking coordinate measuring system and the best measurement area are studied.The errors introduced by the layout are analyzed and simulated.5.A multi-lateral measurement experiment system based on laser tracked absolute length measurement was built and a measurement control program was prepared.The error sources and the measurement uncertainty of the system are analyzed.Combined with the optimal layout theory,the site network test is carried out.The self-calibration model and system measurement accuracy are experimentally verified.Experimental results show that the system can achieve better than 20 ?m coordinate measurement accuracy in 20 m measurement space.