Development of a faster algorithm for extracting contact position from instrumented wheelset based on frequency analysis and its implementation in online processing system

Abstract

Instrumented wheelsets are widely used in the railway industry for the purpose of measurement of the wheel-rail interaction forces, which are crucial factors in a running safety assessment. Information on lateral contact position between wheel and rail is also an important factor when discussing the wheel-rail contact conditions, such as the friction coefficient at the contact point. However, it is difficult to measure the contact position by using ordinary instrumented wheelsets since they are specialized only for the measurement of interaction forces. Therefore, the authors have proposed a signal processing procedure to extract information of contact position from bridge circuits constructed for the measurement of the lateral forces between wheel and rail by using bending and shear strains of wheel webs in a previous work. The purpose of this paper is to develop an online processing system which implements the proposed signal processing procedure. The original procedure requires long computational time and is not suitable for an online processing. As the first step to develop the processing system, this paper proposes a faster algorithm of signal processing procedure based on frequency analysis for extracting information of contact position from instrumented wheelset at first. Using the faster algorithm, a multi-rate processing system was developed to acquire the strain data at a high frequency and to execute the signal processing at a low frequency. The performance of the developed system was evaluated with a single-wheelset roller-rig test.

Keywords

• railway
• running safety assessment
• wheel-rail interaction
• flange climb derailment