Abstract:
With today's increase in large parts manufacturing and assembly requirements, the demand for precision manufacturing and assembly of such products are constantly improved. High-precision measurement and control has become an important factor restricting the development of high-ranking manufacturing. A three-dimensional coordinate measurement system based on laser tracking and absolute length measurement was developed. The system consisted of four absolute laser trackers and a host computer. The ADM module in the absolute laser tracker provided the distance from the target point to four basis points. And the three-dimensional coordinate value of the target point was calculated by the multilateral method. The system overcame the shortcomings of the laser tracking interferometer and can widen the application range of the measuring system. Simultaneously, in order to improve the accuracy of the self-calibration algorithm, a distance-dependent residual model was proposed and studied. The feasibility and accuracy of the self-calibration algorithm were illustrated by experiments. After the calibration of the system parameters was completed efficiently, the precision of the measurement system was tested. The experimental results show that the system has a measurement error of less than 20 m in a large space of 20 m and the measurement uncertainty is 12.3 m. Compared with a single absolute laser tracker system, the accuracy of the system has greatly improved. The system realizes on-line, high-efficient and accurate three-dimensional coordinate measurement in the industry scene.