The present invention relates to a welding operation measurement system that measures a welding operation.
With recent social circumstances, the manufacturing environment has changed significantly. For example, it has become difficult to maintain manufacturing skills due to an increase in overseas production, an increase in procured goods from abroad, a decrease in skilled technicians, and the like, so that quality control has been exposed to more severe conditions. As a conventional method for passing down a skill, a skill has been succeeded by direct teaching from a skilled technician. However, a means for conveying the skill is insufficient, and the teaching is often intuitive. Thus, it takes time to teach the skill, or the skill is inaccurately passed down, so that the skill may be lost without being completely passed down.
Meanwhile, approaches to measure and evaluate an experienced skill have been taken with the development of measurement techniques in recent years. As a method for solving the problem in the conventional skill transfer, an approach to measure and evaluate an operation of a target person using various measurement devices has been performed. There has been proposed a method for comparing measured data with data measured in the past to evaluate a quality and use a result of the evaluation in quality control and training of a welding operation.
PTL 1 discloses a method of measuring data on a welding environment including a welding target and behavior of a welder during a welding operation when manual welding is performed, extracting a feature amount of a welding state during welding from the measured data to determine a quality of a manually welded state, and transmitting a result of the determination to the welder to control a welding quality.
PTL 1: JP 2001-171140 A
The method of PTL 1 describes that the movement is managed by acquiring the movement of the welder in three-dimensional coordinates, but does not describe a detailed method such as a measurement principle.
Further, when a shape of the welding target object is complicated, it is impossible to accurately measure positional relationship between the welding target object and the welder, and it is difficult to acquire relative information.
In view of the above, an object of the present invention is to provide a welding operation measurement system that can accurately measure a positional relationship between a welding target object and a welder and acquire accurate three-dimensional coordinate data of a shape of a work.
In order to solve the above problems, a welding operation measurement system of the present invention includes: a light irradiation unit that emits light; a three-dimensional coordinate measurement unit that measures light reflected from a marker attached to a work and a torch and calculates three-dimensional coordinate data of the work and the torch, the marker reflecting the emitted light; and an arithmetic unit that converts a shape of the work into coordinates based on input three-dimensional graphic data and the three-dimensional coordinate data of the work and generates coordinate data of a shape of the work.
As the light irradiation unit, either a unit that emits light having a predetermined wavelength or a unit that emits light having a predetermined wavelength range may be used. Further, a self-luminous marker attached to the work and the torch may be used, instead of the light irradiation unit.
Further, when the unit that emits the light having the predetermined wavelength range is used as the light irradiation unit, it is preferable to provide a filter that extracts light of a specific wavelength and to use one that measures the light of the specific wavelength out of the light reflected from the marker as the three-dimensional coordinate measurement unit.
It is possible to provide the welding operation measurement system that can accurately measure the positional relationship between the welding target object and the welder and acquire the accurate three-dimensional coordinate data of the shape of the work.
Hereinafter, each embodiment will be described with reference to the drawings.
Reference sign 1 denotes a control unit (control device), reference signs 2a, 2b, 2c, 2d, and 2e represent a marker measurement camera, reference sign 3 denotes a marker, reference sign 4 denotes a welder, reference sign 5 denotes a light-shielding surface, reference sign 6 denotes a torch, reference sign 7 denotes a welding target object, reference sign 8 denotes a semi-automatic welding power supply, reference sign 9 denotes a current/voltage measurement device, reference sign 10 denotes a temperature/humidity/wind measurement device, and reference sign 11 denotes an absorption film. The control unit (control device) 1 is, for example, a computer including: an arithmetic processing device (for example, a CPU); a storage device that stores a program or data to be executed by the arithmetic processing device (for example, a semiconductor memory such as a ROM and a RAM, or a magnetic storage device such as an HDD, which corresponds to a “storage unit” to be described below), a display device (for example, a monitor or a touch panel) that displays a calculation result of the arithmetic processing device.
The operation of welding the welding target object 7 by the welder 4 who is a worker by semi-automatic welding is measured. The marker measurement cameras 2a, 2b, 2c, 2d, and 2e, which are light irradiation units, are arranged around the welder 4 and the welding target object 7. The marker measurement cameras 2a, 2b, 2c, 2d, and 2e can set light to have a wavelength of 350 nm to 11 μm so as to avoid a light wavelength at the time of arc welding, and emit the light. In the present embodiment, light of 850 nm is applied. The marker 3 is attached to the welding target object 7 (work 18), the torch 6, the welder 4, the light-shielding surface 5, a filler metal 19, and the like, and may be one that reflects light or one that is self-luminous. In the present embodiment, a marker coated with a paint that reflects light is used. Note that the marker may be provided on at least the torch 6 and the welding target object 7 in the present invention, and more detailed coordinate data can be obtained by further providing the marker on the welder 4, the light-shielding surface 5, the filler metal 19, and the like. The marker measurement cameras 2a, 2b, 2c, 2d, and 2e, the current/voltage measurement device 9, the temperature/humidity/wind measurement device 10 are connected to the control unit 1. Operations of the respective measurement devices are controlled by the control unit 1, and operation data such as a measured average moving speed of the torch, a torch height, a weaving condition, a torch angle, a supply amount of the filler metal, an angle of an elbow having the torch, a head position and environmental data such as a current value, a voltage value, temperature, humidity, wind power are sent to the control unit 1, and stored as storage data in the storage unit in the control unit 1. Further, the control unit 1 has a function of displaying measured data.
Note that the storage unit also stores three-dimensional graphic data, which is input three-dimensional CAD data, and calculated three-dimensional coordinate data, which will be described later. Further, the storage unit is provided inside the control unit 1 in the above description, but may be provided outside the control unit 1.
The control unit 1 includes: a three-dimensional coordinate measurement unit 21 that measures the light reflected from the markers 3 attached to the welding target object 7 (work 18) and the torch 6, which reflect the light emitted from the marker measurement cameras 2a, 2b, 2c, 2d, and 2e as the light irradiation devices, and calculates three-dimensional coordinate data of the work 18 and the torch 6; and an arithmetic unit 22 that converts a shape of the work 18 into coordinates based on three-dimensional graphic data and the three-dimensional coordinate data and generates coordinate data of the shape of the work 18. The arithmetic unit 22 includes: a shift amount calculation unit 23 that matches the input three-dimensional graphic data and the three-dimensional coordinate data of the work 18 and calculates a shift amount; and a correction unit 24 that corrects the coordinate data of the shape of the work 18 based on the calculated shift amount. The three-dimensional coordinate measurement unit 21, the shift amount calculation unit 23, and the correction unit 24 indicate functions of the program executed by the arithmetic processing unit of the control unit 1, which is the computer. Details will be described hereinafter.
Three-dimensional drawing data 12 of the welding target object 7 is three-dimensional CAD data that has been stored in advance or input. Three-dimensional coordinate data, which are marker coordinate data 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h of the welding target object 7, are position coordinate data of the respective markers 3 illustrated in
A measurement result (positional relationship) of welding operation data at welding time or a welding position as illustrated in
Specifically, a feeding amount of the filler metal, movement of the torch 6 in a welding progress direction, the deformation amount of the work, and the angle of the right elbow were calculated based on the coordinate data obtained by measuring the markers 3 attached to the torch 6, the work, the filler metal, and the worker. It was confirmed from the calculated feeding amount of the filler metal and movement of the torch 6 in the welding progress direction that the filler metal and the torch had a periodic operation pattern of repeating stop and moving.
Further, it was confirmed that the angle of the right elbow was increased in conjunction with the torch operation. Further, it was confirmed that the deformation amount increased over the welding time as a result of calculating the deformation amount of the work from the coordinates of the marker 3 attached to the work. Since the deformation amount is quantitatively evaluated on the spot, it is possible to offset the deformation amount in torch coordinates when measuring the next welding pass, and a relative position of the torch 6 with respect to the work can be measured with high accuracy. When the relative positional relationship is measured by attaching the marker 3 to the torch 6, the work, the filler metal, and the worker in this manner, it is possible to also evaluate a linked operation with high accuracy.
From the above description, the welding operation measurement system of the present embodiment can accurately measure the positional relationship between the work, which is the welding target object, and the torch provided with the marker possessed by the welder, that is, the positional relationship between the welding target object and the welder, and it is possible to provide the welding operation measurement system that acquires the accurate three-dimensional coordinate data of the shape of the work.
Although the semi-automatic welding has been described in the present embodiment, the measurement is similarly performed even in TIG welding and the like, and the measurement is similarly performed by attaching a marker to a filler metal even in the case of using the filler metal.
Further, the marker is recognized by emitting the light having the predetermined wavelength (850 nm) from the light irradiation unit in the present embodiment, but a light source having a wide wavelength range (predetermined wavelength range) may be used as the light irradiation unit. In such a case, a three-dimensional coordinate measurement unit preferably includes a filter that extracts light of a specific wavelength from reflected light and measures the light of the specific wavelength out of the light reflected from a marker attached to a work or a torch.
Further, when the self-luminous marker is used instead of the marker that reflects light, either a marker that emits light of a predetermined wavelength or a marker that emits light having a wide wavelength range (predetermined wavelength range) can be selected. When the latter, that is, the marker having the wider wavelength range is selected, it is preferable to use a filter that extracts light of a specific wavelength similarly to the reflective marker. Further, it is also possible to impart a filter function of reflecting light of a specific wavelength to the marker.
It is possible to provide an inertial sensor 14, which is an acceleration angular velocity measurement device, on the torch 6 to measure a three-axis acceleration and a three-axis angular velocity. The welding method and the welding target object 7 are the same as those in the first embodiment.
Operation data, such as welding work operation data, welding state data, welding environment data, and welded portion quality data, acquired in the past is stored in advance and is compared with operation data, such as welding work operation data, welding state data, and welding environment data, newly measured by a measurement unit to determine a quality of a welded portion by a quality determination unit. This quality determination unit can also evaluate an operation level of a welder.
Note that the welding work operation data may be measured by a global positioning system, an indoor global positioning system, a stereo camera, or the like other than an acceleration/angular velocity/geomagnetic measurement devices such as the above-described inertial sensor 14.
Specifically, when welding the welding target object 7, with the configuration according to the first embodiment, storage data stored in the storage unit, such as measured marker coordinate data, data of a torch height relative to welding time or a welding position as illustrated in
As a result of correlation analysis with the quality based on the storage data according to the first embodiment, an average moving speed of the torch and an angular velocity of the torch were extracted as feature amounts having a strong correlation with the quality.
The welding-target-object-simulated part 15 is the same as those in the first and second embodiments. When the welding operation measurement system described above is used, the feature amount analyzed in the first embodiment as having the strong correlation with the quality can be trained without actually performing welding, and the welding operation measurement system can be used as the education system.
The average moving speed and the angular velocity of the torch were selected as the feature amounts similarly to the second embodiment. Therefore, the inertial sensor 14, which is an operation data measurement unit capable of measuring and calculating these feature amounts, was attached to the torch similarly to the second embodiment (
Further, the imaging unit may be a stereo camera. When the stereo camera is used, it is possible to measure a positional relationship between the welding-target-object-simulated part 15 and the simulated torch 17, that is, to acquire three-dimensional distance information and position information. Note that the marker provided on the torch has been measured with the camera to acquire the accurate position information of the marker so far, it is possible to measure the positional relationship between the welding-target-object-simulated part 15 and the simulated torch 17 based on the acquired three-dimensional distance data without using the marker if the stereo camera is used.
The three-dimensional coordinate measurement unit 21 calculates three-dimensional coordinate data of the welding-target-object-simulated part 15, which is the welding target object, and the simulated torch 17 based on the position information acquired by the imaging unit and the various operation data described above. As also described in the first embodiment, the arithmetic unit 22 converts a shape of the welding-target-object-simulated part 15 into coordinates based on input three-dimensional graphic data and the three-dimensional coordinate data of the welding-target-object-simulated part 15, and generates coordinate data of the shape of the welding-target-object-simulated part 15.
The simulated torch 17 has a welding start switch, and is recognized as an energized state if the switch is in a pressed state. When a torch distal end is within a predetermined distance from the welding-target-object-simulated part 15 in the energized state, an arc is displayed on the head-mounted display, which is the display unit, and accordingly, a molten pool is displayed. When the welder 4 moves the simulated torch 17, the arc and the molten pool move accordingly. The control unit 1 refers to data stored in the past, and can reproduce the arc, the molten pool, a welding sound, a welding current/voltage in accordance with an operation of the torch. That is, on the head-mounted display as the display unit, it is possible to display the video of the welding operation reproducing the arc, the molten pool, the welding sound, the welding current/voltage in accordance with the operation of the torch based on the generated coordinate data of the shape of the welding-target-object-simulated part 15 and the operation data stored in advance.
As can be seen from
In the present system, it is possible to store the accurate operation data, such as the measured marker coordinate data, the data of the torch height relative to the welding time or welding position, and the data of the right elbow angle relative to the welding time or welding position, and thus, it is possible to refer to training history and control an operation skill level.
Although the education system has been constructed using the virtual system in the present embodiment, it is also possible to perform training while actually performing welding using actual welding target object and torch.
In the present invention, it is possible to provide the welding operation measurement system that can accurately digitize the welding operation, efficiently carry out a skill transfer by utilizing such numerical data for the education systems or the quality control, improve the quality of manufacturing, and contribute to reduction of a failure rate.
Number | Date | Country | Kind |
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2018-031501 | Feb 2018 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2019/006954 | 2/25/2019 | WO | 00 |