Abstract
A hoist rope rupture accident of an elevator in a subway station occurred in 2011. According to the accident report, the causes were deterioration of strength of the wire rope by breaks of inner wires, and insufficiency of the inspection method regarding breaks of inner wires and red rust on the wire ropes. Although detection of the breaks of inner wires is difficult, the breaks relate to the decrease of diameter of wire rope and an occurrence of red rust. Therefore measurement of diameter of wire ropes and confirmation of the occurrence of red rust are required in periodic inspection at present. In general, diameter of wire ropes is measured by vernier calipers, and red rust is checked with eyes. However it is preferable to measure and check more accurately and homogenously from the viewpoint of recent accidents and global requirements. This study deals with development of a soundness evaluation system of wire rope by image processing. The system consists of a digital camera and a computer. The camera takes digital images of wire rope. The computer analyzes the digital images and calculates the diameter of wire rope from the digital images. Additionally red rust is also checked by analyses of the digital images. In this paper, a concept of the system and verification using wire ropes were described as a fundamental study of development of the system. As a result, it was confirmed that the system has adequate accuracy of diameter measurement and red rust detection.
