Development of measuring apparatus for contact wire wear by sodium vapor lamps

Abstract

Performance requestsIn electric railways in Japan, inspection cars are running at commercial speed, in order to measure wear of contact wires. We have developed an apparatus to measure the contact wire wear with a light source of sodium vapor lamps of simpler mechanism and smaller size than that of current apparatus. This appa- ratus measures the width of wear surface by an optical method, and converts it into a residual height, This apparatus has been used for JR Yamagata Shinkansen in JR. On the other hand, we miniaturized this apparatus further, and developed an overhead contact line inspection system for rail-and-road cars. The results of field tests show that it can be used at a standard deviation of measuring error of 0.3 mm in daytime.The apparatus should have the following performance.(1) It can be used in daytime.(2) The measurement frequency is 500Hz or over to make (3) The measurement range for horizontal deviation is (4) It Can meaSUre maximum four Wires at the Same time. 2.2. The method of measurement the measuring pitch 70" in 130kmh running. 700".In Japan, the cross section of the contact wire has a circular shape with two grooves. Fig. 1 shows the cross section of the contact wire. The wear surface of contact wire becomes flat due to the sliding of pantograph and the size in the direction of height decreases. To measure the

Measurement Method for Contact Wire Wear Based on Stereovision

“…In order to cover the range of stagger with high resolution, multiple line-scan cameras were adopted by ATON and MEDES [7]. To minimize the influence of the variation in contact wire height on measurement, Van Gigch et al [15] and Borromeo et al [7] proposed a method of adjusting the focal lengths of cameras online separately, while Kusumi et al [16] developed a method for keeping a constant distance from cameras to contact wire by controlling the mirrors. You et al [12] derived the equation of calculating the wear width using the pinhole camera model, which involved the impact of height variation on resolution.…”

“…A lookup-table method is developed to exactly determine the image resolution in various sections of measurement plane. Compared with the methods reported in the literature [7,15,16], no additional adjustment device is required to adjust the focal lengths of cameras or maintain a constant working distance in this study. Currently, little attention is being paid to the impact of stagger variation on resolution.…”

“…Currently, little attention is being paid to the impact of stagger variation on resolution. In most existing studies, the focus is on minimizing the influence of the variation in contact wire height on measurement [7,15,16] or on evaluating the impact of height variation on resolution [12]. In this study, the impact of both the height variation and the stagger variation on the image resolution has been taken into account by using the lookup-table method, which ensures the accuracy of the wear measurement of contact wires.…”