A Noncontact Cutterhead Dynamic Coordinate Measurement Method for Double-Shield TBM Guidance Based on Photographic Imaging

This article presents a novel noncontact real-time dynamic coordinate measurement method based on photographic imaging for double-shield tunnel boring machine (TBM) guidance. The method is realized by a photoelectric target, an industrial camera, a laser target, and a total station through a coordinate transformation algorithm. The photoelectric target and the camera are fixed on the rear end-face of the front shield and the front end-face of the support shield, respectively. The camera captures the image of the photoelectric target to calculate the pose of the photoelectric target. Then, the 3-D coordinate of the cutterhead center is measured in real time by the coordinate transformation chain. Subsequently, the guidance of the double-shield TBM is accomplished by comparing the 3-D coordinate with the designed tunnel axis. Under vibration conditions where the frequency is 10 Hz, the standard deviation of horizontal/vertical deviation is better than 4 mm, and the standard deviation of yaw, pitch, and roll angle is better than 0.08°. In a
$3\,\,\text {m} \times 2\,\,\text {m} \times 6\,\,\text {m}$
measurement volume, the static position measurement accuracy is better than 5 mm. Experimental results show that the method is feasible and valid for the double-shield TBM guidance system.