Wavelet Transform-Based Approach to Defect Identification in Railway Carbon Contact Strips

Abstract

Pantographs of electric rail vehicles are fitted with carbon contact strips, which slide along the contact wire of catenary to provide constant electrical contact. Contact strips are exposed to wear and damages. Using damaged contact strips significantly increases the risk of catenary rupture. Therefore, their technical condition has to be inspected frequently. In previous work a 3D laser scanning system was proposed for recording contact strips surface shape when vehicles pass an inspection point on a railway line. The system was complimented with an effective automatic wear estimation algorithm. However, this algorithm is insensitive to some shallow defects which are considered hazardous. This paper presents defects identification approach based on differentiation of contact strips profiles. It is assumed that the hazard of catenary rupture corresponds to the peak value in the differentiated profile. A wavelet transform was used to allow for robust differentiation of profiles featured by low signal-tonoise ratio. A method for choosing well-balanced dilatation parameter was proposed, in order to obtain good accuracy of differentiation of both smooth and narrow-edged contact strip defects. Results of simulations implemented in Matlab confirm that the proposed approach can be applied to an algorithm aiming for automatic defects identification.

Analysis of Measurement Errors in Rail Vehicles’ Pantograph Inspection System

“…The analysis concerns two types of errors in determining z = f(x) profile: peak and RMS of height measurement errors. The first value is essential to damage detection algorithms, which are based on computing derivative function dz/dx = f(x) [10]. In turn, the RMS of errors corresponds to wear estimation accuracy, as minimal CCS thickness is computed using height values averaged in a relatively wide range of widths.…”

A Deep Learning Based Method for Detecting of Wear on the Current Collector Strips’ Surfaces of the Pantograph in Railways

“…Using these simulation results, they offered methods for detecting errors in this system. Judek et al [28] proposed a wavelet transform based approach to identify wear in the pantographs' carbon collector strips. In addition, they performed a simulation and tested their proposed method on the simulation.…”

Research on the delamination wear properties of the pure carbon strip at the high-sliding speed with electric current

“…In the past, numerous technical investigations and researches on the wear of the carbon strip were carried out (Shangguan et al , 2010; Huang et al , 2013; Senouci et al , 1999; Wang et al , 2012a; Muetze and Oh, 2010; Auditeau et al , 2011; Kubo and Kato, 1999; Xiong et al , 2014; Judek and Jarzebowicz, 2015; Yang et al , 2015; Suh, 1973; Yang et al , 2010; Bouchoucha et al , 2004; Kubota et al , 2013; Wang et al , 2012b; Bucca and Collina, 2009; Shunichi et al , 1997; Jia et al , 2007; He and Manory, 2001; Yang et al , 2014; Bajwa et al , 2005; Yen, 1996; Zaidi et al , 2001; Yin et al , 2014; Wang et al , 2012c; Tyagia et al , 2011), which mainly focused on the arc erosion wear and adhesive and abrasive wear of the strip. Some scholars (Muetze and Oh, 2010; Auditeau et al , 2011; Kubo and Kato, 1999; Xiong et al , 2014; Judek and Jarzebowicz, 2015) proposed that arc discharge is the main reason of severe wear of contact materials in the process of the sliding wear with electric current. Some experiments indicated that the arc erosion wear mechanisms of pure carbon strip against copper are because of the synergetic action of oxidation ablation, the local electric arc impact and the high-temperature graphitization under the continuous arcing conditions (Xiong et al , 2014).…”