Study On The Large-scale Space Coordinate Measurement Method Based On Vision Guidance

Large-scale coordinate measurement systems with high precision and long measuring range are widely used in national economy's pillar industry such as aviation, shipbuilding, hydraulic and electric engineering, iron and transportation. As the large equipment manufacturing is developing, the product design and manufacturing techniques are innovating. The large-scale measurement on field has the characteristics of complex measuring environment, diversity of the measured objects, automation of the measuring process and integration of the measuring functions. The traditional measurement system can not satisfy the increasing demands of the large-scale measurement on field. Nowadays, the development of new combined measurement systems with the combination of large-scale measurement and close-range measurement with high flexibility and adaptability is the focus and hot spot in the study of the current large-scale measurement field.Focusing on the key link of combined large-scale measurement technology, that is, the large space global measurement equipment and its related control theories, this paper studied and implemented technical approach of large scale coordinate measurement based on vision guiding. Combining with multi-theodolite measurement technology, camera calibration technology and sophisticated turntable control technology, a series of in-depth study were conducted theoretically and practically. Initial guidance methodology using multi-station conversion and precision aiming methodology based on object recognition and motion model of theodolite and related data splicing technology were proposed and the corresponding experimental verifications were completed. The methodology of automatic laser theodolite measurement is high in feasibility and efficiency which was proved by experiments. The main contents and work of this dissertation are summarized as follows.1 With the investigation of the demands and the developing status of the large-scale coordinate measuring system, according to the urgent requirements of major equipment manufacturing, a new combined large-size measurement method was proposed. The emphasis was laid on the detailed analysis and investigation of the global measurement method, as well as the large-scale coordinate measurement system base on vision guidance. 2 According to the measurement subsystem constituted by multiple precision laser theodolites, the calibration of multi-theodolite system applied in different situations were studied, as well as the coordinate measurement method, the measuring error analysis and the estimation of the best measuring field.3 The initial guidance methodology was presented based on camera calibration technique, coordinate transformation theory and the control theory of the precision rotation stage using the relationship between the camera coordinate system and the theodolite measurement system. The realtime guidance model of the theodolite collimation axis based on the position of the camera was built with system simulation and experimental verification.4 The automatic aiming model was established with the tracking strategy of the theodolites for measured target. The global measurement technology in large view field was studied and the measuring principle based on combined datum from divided areas was presented with the division rule and data selection method. Also the complete information acquisition technique based on the theodolite movement and rotation stage movement was proprosed.5 The experimental verification of the measuring method was conducted with the established hardware platform and the software designed. The error resources and their influnces on the measuring accuracy and efficiency were analyzed. Also the measuring errors and efficiency of the system were evaluated comprehensively.