Welding monitoring system

Patent metadata

Field	Value
Publication number	US-11325209-B2
Application number	US-201716311710-A
Country	US
Kind code	B2
Filing date	Mar 15, 2017
Priority date	Jun 28, 2016
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

To improve quality control of welding, there is included in resistance welding: a magnetic field measuring unit (205) disposed around a welded part and configured to measure a local current at the welded part; a high-speed camera (202) configured to capture an image for measuring local temperature at the welded part from variation of luminance of emission by capturing light emission state of the welded part; a comparison determination unit (106) configured to determine whether or not at least one of current information and temperature information has an abnormal value by comparing the current information calculated based on magnetic field information acquired from the magnetic field measuring unit with past current information and comparing the temperature information measured from an image of the high-speed camera (202) with past temperature information.

First claim

The invention claimed is:

1. A welding monitoring system comprising:
a current measuring unit configured to measure a local current at a welded part in resistance welding of a component to be welded;
a temperature measuring unit configured to measure a local temperature at the welded part;
a data acquisition processing unit configured to acquire welding data for the welded part from at least the current measuring unit and the temperature measuring unit;
a data classification unit configured to classify the welding data using machine learning and store, in a data storage, machine learning results that classify past current information and past temperature information;
a determination unit configured to:
generate, based at least on the machine learning results that classify the past current information and the past temperature information, a normal group and an abnormal group, and
determine whether or not at least one of the current information acquired from the current measuring unit or the temperature information acquired from the temperature measuring unit is abnormal based at least on comparing the current information acquired from the current measuring unit with the past current information and comparing the temperature information acquired from the temperature measuring unit with the past temperature information;

a programmable logic controller configured to output an inspection instruction based on a determination that at least one of the current information acquired from the current measuring unit or the temperature information acquired from the temperature measuring unit is abnormal;
an inspection device configured to perform an inspection of the welded part based on receiving the inspection instruction from the programmable logic controller; and
an inspection information input device configured to provide results of the inspection to the data classification unit to improve an accuracy of the machine learning.

2. The welding monitoring system according to claim 1 ,
wherein the current measuring unit is a magnetic field measuring unit disposed in a vicinity of the welded part, and
the local current is measured based on an intensity of a magnetic field measured by the magnetic field measuring unit.

3. The welding monitoring system according to claim 1 ,
wherein the temperature measuring unit is a camera, and
the local temperature is measured based on a luminance distribution in an image, acquired from the camera, of the welded part.

4. The welding monitoring system according to claim 1 , further comprising
a spectral camera,
wherein the determination unit is configured to determine whether or not at least one of the current information acquired from the current measuring unit, the temperature information acquired from the temperature measuring unit, and the frequency distribution, acquired from the spectral camera, of the welded part is abnormal by comparing a frequency distribution, acquired from the spectral camera, of the welded part with a past frequency distribution.

5. The welding monitoring system according to claim 1 , further comprising
a displacement measuring unit configured to determine displacement information for the welded part by measuring a change in length of the component to be welded which is subjected to the resistance welding,
wherein the determination unit is configured to determine whether or not at least one of the current information acquired from the current measuring unit, the temperature information acquired from the temperature measuring unit, and the change in length, obtained from the displacement measuring unit, of the component to be welded is abnormal based at least on comparing the current information acquired from the current measuring unit with the past current information, comparing the temperature information acquired from the temperature measuring unit with the past temperature information, and comparing the change in length obtained from the displacement measuring unit with past displacement information.

6. The welding monitoring system according to claim 1 , wherein the determination unit is connected to a MES (Manufacturing Execution System).

Assignees

• Hitachi Ltd

Inventors

• Endoh Hisashi
• Yoshikawa Hiroshi
• Yamada Toshihiro

Classifications

• G01J5/0859

  Sighting arrangements, e.g. cameras · CPC title

• B23K11/0026

  Welding of thin articles · CPC title

• B23K11/253

  the measured parameter being a displacement or a position · CPC title

• B23K11/08

  Seam welding not restricted to one of the preceding subgroups · CPC title

• B23K2103/04

  Steel {or steel} alloys · CPC title