Identification of Track Irregularity using Wavelet Transfer Function

웨이브렛 전달함수를 이용한 궤도틀림 식별

  • 신수봉 (인하대학교 대학원) ;
  • 이형진 (창원대학교 대학원) ;
  • 김만철 (한국철도기술연구원 차륜궤도연구실) ;
  • 윤석준 (인하대학교 대학원 토목공학과)
  • Received : 2010.02.10
  • Accepted : 2010.05.31
  • Published : 2010.06.26

Abstract

This paper presents a methodology for identifying track irregularity using a wavelet transfer function. An equivalent wavelet SISO (single-input single-output) transfer function is defined by the measured track geometry and the acceleration data measured at a bogie of a train. All the measured data with various sampling frequencies were rearranged according to the constant 25cm reference recording distance of the track recording vehicle used in the field. Before applying the wavelet transform, measured data were regressed by eliminating those out of the range. The inverse wavelet transfer function is also formulated to estimate track geometry. The closeness of the estimated track geometry to the actual one is evaluated by the coherence function and also by FRF (frequency response function). A track irregularity index is defined by comparing the variance of the estimation error from the intact condition and that from the current condition. A simulation study has been carried out to examine the proposed algorithm.

본 연구에서는 웨이브렛 변환을 이용하여 궤도틀림을 식별하는 방법을 제시하였다. 궤도틀림과 대차 가속도응답신호에 의한 등가 웨이브렛 SISO 전달함수를 정의하였다. 현장에 적용되는 검측차의 25cm단위 궤도검측 기준에 맞추어 궤도틀림과 대차가속도 응답신호를 조정하였다. 웨이브렛 변환을 적용하기 전 입력데이터는 웨이브렛 변환 정의 조건에 맞추어 범위를 재조정한 회귀신호이다. 또한, 웨이브렛 역전 달 함수를 정의하여, 궤도틀림을 역 추정하였다. 추정된 궤도틀림과 실제의 궤도틀림의 비교를 위해 상관도와 FRF를 비교 분석하였다. 예측된 값과 기준 값 과의 잔 차의 분산비로 정의되는 틀림지수를 사용하여 궤도틀림의 이상을 분석하였으며, 개발될 알고리즘을 검증하기 위하여 시뮬레이션 연구를 수행하였다.

Keywords

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