Abstract: To address the practical problem of unstable tunnel formation quality caused by the traditional shield method′s reliance on manual operation experience for segment assembly, a complete set of automatic shield segment assembly technology system is established. The system integrates kinematic model establishment, target posture recognition and calculation, and automatic control of the assembly machine. The calculation methods for the target posture of the segments to be assembled are elaborated in detail using different point cloud data processing techniques for grasping and assembly of the segments, as outlined in the layout scheme and calibration method of the visual sensor. Modifications are made to the hydraulic system of the traditional assembly machine, and a new action control process is designed for the actuating mechanism, which is used to formulate an automatic segment grasping and positioning installation strategy based on the experience of manual segment assembly. Finally, a test platform suitable for the verification of this technology is established, based on the existing super-large diameter earth-pressure balance shield. Furthermore, the processing accuracy of point clouds is discussed in the context of environmental simulation and test safety. The following conclusions are drawn from this analysis: (1)The positional coordinate and attitude angle range that can characterize the repeated recognition accuracy of the target position of the segment are 0.97 mm and 0.031°, respectively. (2)The maximum misalignment between the segment blocks and the ring after assembly is 5.28 mm and 6.29 mm, respectively, which meets the engineering acceptance specifications.

Key words: shield segment, automatic assembly, posture recognition, automatic control, experimental verification