Mobile railway track defect detection

Patent metadata

Field	Value
Publication number	US-11879814-B2
Application number	US-201816647189-A
Country	US
Kind code	B2
Filing date	Sep 18, 2018
Priority date	Sep 18, 2017
Publication date	Jan 23, 2024
Grant date	Jan 23, 2024

Abstract

A railway track defect detection system may include a mobile defect detection platform and a modal parameter analyzer. The platform may include an excitation mechanism (e.g., an excitation hammer or wheels that are in contact with a railway track) to apply multiple impact forces to the railway track while the platform travels along the railway track, and a laser Doppler vibrometer to capture, while the platform travels along the railway track, vibration data representing vibrations of the railway track caused by application of the multiple impact forces by the excitation mechanism. The modal parameter analyzer may be configured to detect, based on the vibration data captured by the laser Doppler vibrometer, a defect in the railway track. For example, changes in vibration amplitudes, mode shapes, damping ratios, or a natural frequency derived from the received vibration data may indicate the presence of a defect in the railway track.

First claim

What is claimed is:

1. A system for detecting internal defects in railway tracks, comprising:
a mobile defect detection platform, including:
an excitation mechanism to apply multiple impact forces to a railway track while the mobile defect detection platform travels along a railway track;
a first laser Doppler vibrometer to capture, while the mobile defect detection platform travels along the railway track, vibration data representing vibrations of the railway track caused by application of the multiple impact forces by the excitation mechanism at a first location relative to the excitation mechanism;
a second laser Doppler vibrometer to capture, while the mobile defect detection platform travels along the railway track, vibration data representing vibrations of the railway track caused by application of the multiple impact forces by the excitation mechanism at a second location relative to the excitation mechanism; and
a modal parameter analyzer to detect, based at least in part on the vibration data captured by the first laser Doppler vibrometer and the second laser Doppler vibrometer, P′ an internal defect in the railway track.

2. The system of claim 1 , wherein:
the system further comprises an accelerometer coupled to the first laser Doppler vibrometer to measure the vibration of the first laser Doppler vibrometer while the mobile defect detection platform travels along the railway track and an accelerometer coupled to the second laser Doppler vibrometer to measure the vibration of the second laser Doppler vibrometer while the mobile defect detection platform travels along the railway track; and
to detect the internal defect, the modal parameter analyzer is configured to subtract the vibration of the first laser Doppler vibrometer measured by the accelerometer from the vibration data captured by the first laser Doppler vibrometer and to subtract the vibration of the second laser Doppler vibrometer measured by the accelerometer from the vibration data captured by the second laser Doppler vibrometer.

3. The system of claim 1 , wherein:
the excitation mechanism comprises a plurality of wheels mounted on the mobile defect detection platform, the wheels being in contact with the railway track as the mobile defect detection platform travels along the railway track.

4. The system of claim 1 , wherein to detect the internal defect, the modal parameter analyzer is configured to, for each of the multiple impact forces applied by the excitation mechanism:
determine the magnitude of the impact force; and
normalize the vibration data corresponding to the impact force based on the determined magnitude.

5. The system of claim 1 , wherein to capture the vibration data, the first laser Doppler vibrometer and the second laser Doppler vibrometer are each configured to sample laser beams reflected off the railway track at a predetermined constant frequency, the predetermined constant frequency being dependent on the vibration frequency of the railway track.

6. The system of claim 5 , wherein to detect the internal defect, the modal parameter analyzer is configured to:
determine a value of a modal parameter for each of a plurality of vibration data samples; and
detect a change in the value of the modal parameter indicative of an internal defect in the railway track.

7. The system of claim 1 , wherein the modal parameter analyzer comprises:
an input/output interface coupled to the first laser Doppler vibrometer and the second laser Doppler vibrometer to receive at least a portion of the vibration data captured by first laser Doppler vibrometer and the second laser Doppler vibrometer;
a processor;
a memory storing program instructions that when executed by the processor cause the processor to:
determine, based on the received vibration data, that vibration amplitudes, mode shapes, damping ratios, or a natural frequency derived from the received vibration data are indicative of the presence of an internal defect in the railway track.

8. The system of claim 1 , wherein the speed at which the mobile defect detection platform travels along the railway track is controlled by a predetermined speed parameter value, the predetermined speed parameter value being dependent on the vibration frequency of the railway track.

9. A od for detecting internal defects in railway tracks, comprising:
applying, by an excitation mechanism of a mobile defect detection platform to a railway track as the mobile defect detection platform travels along the railway track, multiple impact forces;
capturing, by at least two laser Doppler vibrometers of the mobile defect detection platform while the mobile detect detection platform travels along the railway track, vibration data representing vibrations of the railway track caused by application of the multiple impact forces by the excitation mechanism; and
detecting, based at least in part on the vibration data captured by the at least two laser Doppler vibrometers, an internal defect in the railway track.

10. The method of claim 9 , wherein:
the method further comprises measuring, by an accelerometer coupled to each of the at least two laser Doppler vibrometers, the vibration of each of the laser Doppler vibrometers while the mobile defect detection platform travels along the railway track; and
detecting the internal defect comprises subtracting the vibration of each of the laser Doppler vibrometers measured by the accelerometer from the vibration data captured by each of the laser Doppler vibrometers.

11. The method of claim 9 , wherein:
the excitation mechanism comprises a plurality of wheels mounted on the mobile defect detection platform, the wheels being in contact with the railway track as the mobile defect detection platform travels along the railway track.

12. The method of claim 9 , wherein detecting the internal defect comprises, for each of the multiple impact forces applied by the excitation mechanism:
determining the magnitude of the impact force; and
normalizing the vibration data corresponding to the impact force based on the determined magnitude.

13. The method of claim 9 , wherein capturing the vibration data comprises sampling laser beams reflected off the railway track at a predetermined constant frequency, the predetermined constant frequency being dependent on the vibration frequency of the railway track.

14. The method of claim 13 , wherein detecting the defect comprises:
determining a value of a modal parameter for each of a plurality of vibration data samples; and
detecting a change in the value of the modal parameter indicative of a defect in the railway track.

15. The method of claim 9 , wherein the speed at which the mobile defect detection platform travels along the railway track is controlled by a predetermined speed parameter value, the predetermined speed parameter value being dependent on the vibration frequency of the railway track.

16. A mobile defect detection platform for detecting internal defects in a target structure, including:
an excitation mechanism to apply multiple impact forces to the target structure while the mobile defect detection platform travels parallel to a face of the target structure;
at least two laser Doppler vibrometers to capture, while the mobile defect detection platform travels parallel to the face of the target structure, vibration data representing vibrations of the target structure caused by application of the multiple impact forces by the excitation mechanism; and
an input/output interface coupled to a modal parameter analyzer to communicate at least a portion of the vibration data captured by t

Assignees

• Univ Texas

Inventors

• Kaynardag Korkut
• Salamone Salvatore

Classifications

• G01M5/0066 Primary

  by exciting or detecting vibration or acceleration (vibration testing of structures G01M7/00) · CPC title

• G01M5/0025

  of elongated objects, e.g. pipes, masts, towers or railways (G01M5/0058 takes precedence) · CPC title

• G01M5/0075

  by means of external apparatus, e.g. test benches or portable test systems (G01M5/005 takes precedence) · CPC title

• G01N29/045

  by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks (measuring resonant frequency G01H13/00; measuring strength properties by application of mechanical stress G01N3/00) · CPC title

• G01N29/2418

  using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics (photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046) · CPC title