WInBot: A Disc Cutter Wear Inspection Robot for a Tunnel Boring Machine

Abstract

During excavation, the disc cutter (DC) of a tunnel boring machine (TBM) will experience wear. WInBot, a DC wear inspection robot, is developed for 5 m-diameter-class TBMs and two wear measurement methods are proposed. WInBot has a high expansion ratio actuator to allow operation in the narrow space around the cutter head. The measurement arm can extend widely and can be compacted 2.7 and 1.5 times for vertical and horizontal expansion and contraction ratios, respectively. WInBot acquires point cloud data for a DC surface or other parts and estimates the amount of DC wear using an iterative closest point matching algorithm. Experiments are conducted to examine the accuracy of the proposed measurement methods. When only DC surface data is used, the estimation accuracy drops when the DC is severely worn and its geometric features disappear. The other method, which uses additional parts, is resistant to the difference in DC wear and achieves measurements accurate to 1 mm.