Study On Theory And Technology Of Position-Pose Measurement System Of Shield Machine Based On The Nondiffracting Beam

Shield machine is the large-scale equipment used in underground tunnel construction. To ensure the quality of shield tunneling and make shield machine advance along the designed alignment, it is very important to measure the position-pose of shield machine precisely. Now the position-pose of shield machine is usually measured by laser measurement technology in the advanced guiding system. In order to manufacture the homemade guiding system, it is necessary to self-develop the position-pose measurement system of shield machine. After deep research on measurement technologies of the position-pose of shield machine, the measurement method of the position-pose of shield machine based on the non-diffracting beam technology is proposed, considering the non-diffracting beam has the feature of a very small central spot diameter and high accuracy of center positioning.The main contents and achievements include:The position-pose measurement system of shield machine based on the non-diffracting beam is developed. And the electronic target which is the key equipment is designed. The non-diffracting beam is of high quality within the angle range.Based on the ring pattern characteristic of the non-diffracting beam, an ideal ring-based matching algorithm is proposed to detect the global center of the non-diffracting beam and the difficult problem is solved. The true spot and simulated spot in which various noises are added are used to check the precision of the algorithm. The experiments show that subpixel sensitivity and high anti-interference ability can be obtained by using the algorithm.Since the optic center of optic system in the electronic target is difficult to accurately find, a new direct mapping calibration method is proposed to calibrate the electronic target. So the spot center location in CCD fixed in the electronic target and the incident angle data of the total station are combined, and constitute the mapping database. The method of calculating the spatial angle of the incident laser by the spot center location is researched. The interpolation method based on Delaunay triangulation is used in the mapping database under cartesian coordinates system and polar coordinates system respectively to calculate the spatial angle of the incident laser. The precisions of the interpolation method in two coordinates systems are compared. The experiments show that the precision of the spatial angle calculated in the polar coordinates system is higher.The errors of the total station and the electronic target in measuring process are analyzed. The errors of attitude angles and the center of the head of shield machine measured by the position-pose measurement system are derived. The result shows that the measuring precision of attitude angles is higher than one milli-radian and the measuring precision of the head of shield machine could be reached to be in a millimeter-level.The software of measuring the position-pose of shield machine is developed. The real-time position-pose of shield machine can be calculated quickly by the software. Two simulated experiments are designed. The analysis of experiment data shows that the measurement precision of the position-pose measurement system based on the non-diffracting beam is high, which could meet the precision requirement of the shield machine guidance.