Displacement Distribution Monitoring of an Unloader Crane in Ironworks Using High-speed and High-resolution Vision

In this study, we develop a high-speed, high-resolution vision system that enables real-time measurement of deflection displacement distribution in cranes with long beam structures. It can measure dynamic displacement distribution with sub-pixel accuracy in real time by executing digital image correlation for 4096×904 images at 100fps. Millimeter-level deflections at tens of points on a crane are measurable with the position of its moving load when a camera is tens of meters away from the crane. The trolly of a crane indicates the load position, and our system can also analyze deflection influence lines at all points on the crane as speed-invariant features that indicate its structural property. The effectiveness of our vision-based displacement measurement is demonstrated by showing experimental results for (1) a 1-m-length belt conveyor, and (2) an unloader crane with a 98-m beam structure operating in ironworks.