An Improved Monocular-Vision-Based Method for the Pose Measurement of the Disc Cutter Holder of Shield Machine.

The manual disc cutter changing of the shield machine has greater security hidden danger, which leads to the urgent need to develop a disc cutter changing robot to replace the over-worn disc cutters. The rotation positioning error of the large diameter cutter head, the motion control error of the disc cutter changing robot, and the complexity of the disc cutter changing bin environment lead to the inaccuracy of the actual pose of the disc cutter. Therefore, it is necessary to increase the machine vision measurement system to accurately measure the pose of the disc cutter or its holder. This paper proposes a cutter holder positioning method, which uses the parallel line features and actual contour area of the cutter holder to determine its initial pose, and then uses the initial pose to calculates its accurate pose based on the distance matching method. The innovation of the method is that the pose measurement is carried out through the unique characteristics of the cutter holder, and it combines the initial pose estimation method based on the geometric characteristics of the cutter holder with the distance matching method which depends on the initial pose to solve the cutter holder pose. Simulation analysis shows that the accuracy of the proposed method is close to that of the most advanced PnP algorithms, and its robustness is better than others. Experimental results also verify the high accuracy of the proposed method.