EP-4741815-A1 - METAL BODY MONITORING DEVICE AND METAL BODY MONITORING METHOD

EP4741815A1EP 4741815 A1EP4741815 A1EP 4741815A1EP-4741815-A1

Abstract

A metal body monitoring apparatus has a magnetic detection device, a distance detection device, and a processing device. The magnetic detection device has a magnetic sensor unit, and the magnetic sensor unit is provided on a moving body that relatively moves over a metal body, and detects a generated leakage magnetic field in a non-contact manner. The distance detection device is provided on the moving body and detects a movement distance relative to the metal body of the moving body. The processing device converts first data representing the time-series of the detection signal strength from the magnetic detection device into second data representing a relationship between the movement distance and the detection signal strength based on the movement distance at each time point detected by the distance detection device. The processing device extracts a spectral response in a wave number space specified from the second data, and outputs monitoring information which is information based on the extracted spectral response.

Inventors

KAWABATA, RYUZO

Assignees

Hitachi, Ltd.

Dates

Publication Date: 20260513
Application Date: 20240117

Claims (12)

A metal body monitoring apparatus, comprising: a magnetic detection device having a magnetic sensor unit that is provided on a moving body relatively moving over a metal body, and detects a leakage magnetic field generated from the metal body in a non-contact manner; a distance detection device provided on the moving body and detecting a movement distance relative to the metal body of the moving body; and a processing device connected to the magnetic detection device and the distance detection device, wherein the processing device converts first data representing a time-series of a detection signal strength from the magnetic detection device into second data representing a relationship between a movement distance and the detection signal strength based on the movement distance at each time point detected by the distance detection device, extracts a spectral response in a wave number space specified from the second data, and outputs monitoring information which is information based on the extracted spectral response.
The metal body monitoring apparatus according to claim 1, wherein output of the monitoring information is a display of the monitoring information, and the monitoring information is information indicating a correspondence between a spatial frequency and a movement distance of the moving body.
The metal body monitoring apparatus according to claim 2, wherein the correspondence is a color contour of an orthogonal coordinate system of a first axis corresponding to the spatial frequency and a second axis corresponding to the movement distance of the moving body, and a color indicator in accordance with a detection signal strength is arranged in the orthogonal coordinate system.
The metal body monitoring apparatus according to claim 1, wherein the processing device performs spatial filtering processing in accordance with a size required for monitoring the metal body, on the second data, and in data subjected to the spatial filtering processing, a spectral response in a wave number space is extracted for each of sections to be monitored in the metal body.
The metal body monitoring apparatus according to claim 4, wherein the processing device performs interpolation processing of samplings of a movement distance in the second data so that the samplings are performed at equal intervals, and the spatial filtering processing is performed on the second data subjected to the interpolation processing.
The metal body monitoring apparatus according to claim 4, wherein the processing device performs continuous wavelet analysis to extract the spectral response in the wave number space for each of the sections.
The metal body monitoring apparatus according to claim 4, wherein the processing device performs a signal separation by discrete wavelet analysis to extract the spectral response in the wave number space for each of the sections, and continuous wavelet analysis is used for the separated signal.
The metal body monitoring apparatus according to claim 4, wherein the processing device performs a short-time Fourier transform to extract the spectral response in the wave number space for each of the sections.
The metal body monitoring apparatus according to claim 8, wherein the metal body may be in the form of being cyclically arranged along a relative moving direction of the moving body.
The metal body monitoring apparatus according to claim 1, wherein the magnetic detection device has a plurality of magnetic sensor units arranged in a direction perpendicular to a relative moving direction of the moving body.
A metal body monitoring method, causing a computer to execute: converting first data representing a time-series of a detection signal strength from a magnetic detection device into second data representing a relationship between a movement distance and the detection signal strength based on the movement distance at each time point detected by a distance detection device; extracting a spectral response in a wave number space specified from the second data; and outputting monitoring information which is information based on the extracted spectral response, wherein the magnetic detection device is a device having a magnetic sensor unit that is provided on a moving body relatively moving over a metal body, and detects a leakage magnetic field generated from the metal body in a non-contact manner, and the distance detection device is a device that is provided on the moving body and detects a movement distance relative to the metal body of the moving body.
A computer program, causing a computer to execute: converting first data representing a time-series of a detection signal strength from a magnetic detection device into second data representing a relationship between a movement distance and the detection signal strength based on the movement distance at each time point detected by a distance detection device; extracting a spectral response in a wave number space specified from the second data; and outputting monitoring information which is information based on the extracted spectral response, wherein the magnetic detection device is a device having a magnetic sensor unit that is provided on a moving body relatively moving over a metal body, and detects a leakage magnetic field generated from the metal body in a non-contact manner, and the distance detection device is a device that is provided on the moving body and detects a movement distance relative to the metal body of the moving body.

Description

[Technical Field] The present invention relates generally to monitoring of a metal body. [Background Art] Examples of a metal body include a wire rope. As an example of a monitoring apparatus for a wire rope, a deterioration determination apparatus for a wire rope is disclosed in Patent Literature 1. Patent Literature 1 discloses that "a deterioration determination apparatus for a wire rope includes a detector 30 that detects a deterioration of a wire rope by a magnetic leakage flux method, a data input unit 31 that acquires measurement data from the detector 30, noise component removal means that removes noise components from the data input unit 31, and waveform processing means that extracts data determined as having high correlation with a deterioration factor of the wire rope". [Citation List] [Patent Literature] [Patent Literature 1] Japanese Patent Laid-Open No. 2022-52864 [Summary of Invention] [Technical Problem] Patent Literature 1 discloses the deterioration determination apparatus for a wire rope that detects a deterioration of a wire rope by using a magnetic leakage flux method. In this apparatus, a signal waveform of a detection signal may change depending on a velocity at which the wire rope passes through the detector. In addition, in this apparatus, there is noise (for example, offset drift associated with fluctuation of a position of the detector, and external noise) generated due to an environment or a state in the monitoring of the wire rope, and this noise affects the signal waveform of the detection signal. Therefore, it is difficult to discriminate between a peculiar point which is a point different from a sound portion in the wire rope and the sound portion based on the detection signal (in particular, whether a peculiar point is a damaged point). Patent Literature 1 does not disclose peculiar point discrimination for the wire rope, and a method therefor. Such a problem may also occur in a case where the metal body is a metal body other than a wire rope. In addition, such a problem may occur in a metal body monitoring environment in general in which a magnetic sensor unit (for example, a detector) not in contact with a metal body relatively moves over the metal body. An object of the invention is to enable peculiar point discrimination for a metal body to be monitored in such a metal body monitoring environment. [Solution to Problem] To solve the above problem, a typical metal body monitoring apparatus of the invention has a magnetic detection device, a distance detection device, and a processing device connected to the magnetic detection device and the distance detection device. The magnetic detection device has a magnetic sensor unit, and the magnetic sensor unit is provided on a moving body that relatively moves over a metal body, and detects a generated leakage magnetic field in a non-contact manner. The distance detection device is provided in the moving body and detects a movement distance relative to the metal body of the moving body. The processing device converts first data representing the time-series of the detection signal strength from the magnetic detection device into second data representing a relationship between the movement distance and the detection signal strength based on the movement distance at each time point detected by the distance detection device. The processing device extracts a spectral response in a wave number space specified from the second data, and outputs monitoring information which is information based on the extracted spectral response. [Advantageous Effects of Invention] According to the invention, it is possible to enable peculiar point discrimination for a metal body in a metal body monitoring environment in which a magnetic sensor unit not in contact with a metal body relatively moves over the metal body. Problems, configuration, and effects other than those described above will be clarified by the following description of embodiments. [Brief Description of the Drawings] [Figure 1] Figure 1 is a schematic diagram of a metal body monitoring apparatus according to a first embodiment of the invention.[Figure 2] Figure 2 is a perspective view of a magnetic detection device in the first embodiment.[Figure 3] Figure 3 is a bottom view of the magnetic detection device in the first embodiment.[Figure 4] Figure 4 is a partially cutaway plan view of the magnetic detection device in the first embodiment.[Figure 5] Figure 5 is a schematic diagram illustrating an operating state of a magnetic sensor unit of the first embodiment.[Figure 6] Figure 6 is a schematic diagram illustrating another operating state of the magnetic sensor unit of the first embodiment.[Figure 7A] Figure 7A is an explanatory diagram of processes 1 to 3 regarding a monitoring information extraction and analysis process to which continuous wavelet analysis is applied in the metal body monitoring apparatus according to the first embodiment of the invention.[Figure 7B] Figure 7B is an e