KR20210089521A - auto welding machine using infrared sensor - Google Patents

Abstract

The present invention relates to an auto welding machine using an infrared sensor, wherein a welding torch mounted on a support arm of a transfer device is transferred to perform welding while tracking a weld line between metal plates to be welded. The auto welding machine comprises: first and second infrared sensors mounted on the support arm and spaced apart by a symmetric distance from the welding torch to detect an infrared signal emitted by heating in correspondence to temperature produced from the metal plates to be welded in welding; and a controller for controlling the transfer device so that the transfer device moves along a preset traveling route, wherein the welding torch is transferred so that a mutual error is offset by comparing output signals of the first and second infrared sensors. According to the auto welding machine using an infrared sensor, an infrared ray emitted from a metal plate to be welded by heat generated in welding is detected to enable the welding torch to follow a gap, thereby providing advantages of a simple structure and easy tracking of the weld line.

Description

Automatic welding machine using infrared sensor

The present invention relates to an automatic welding apparatus using an infrared sensor, and more particularly, to an automatic welding apparatus using an infrared sensor capable of automatically performing welding while tracking a welding line.

Industrially, welding is widely used as a method of interconnecting metal plates.

In such welding, in order to perform automatic welding using a welding robot, it is most important to accurately track a welding line that is a joining line between two metal plates to be joined.

Currently, sensors used for automatic tracking of weld lines in GMA welding include mechanical contact sensors, arc sensors, electromagnetic sensors, and vision sensors.

Since the mechanical contact sensor receives a signal by mechanical contact, an error may occur depending on the surface condition of the metal plate to be processed, so it is difficult to use it universally. In addition, in the case of the arc sensor, when weaving, the difference in current values at both ends of the weaving is detected and indirect position information is used, so the position of the torch at the welding place can be detected by tracking the welding line. It can be used for tracking weld lines on thick plates, but cannot be used for welding thin plates.

There are disadvantages. In the case of an electromagnetic sensor, the weld line is measured relatively precisely, but it has a disadvantage that it is easily affected by arc heat and magnetic field.

In addition, in the case of a vision sensor, the image processing process to find the welding line is complicated, and the disturbance caused by arc light or spatter generated during the welding process is severe, so a blocking film must be installed between the camera and the welding torch, which makes the facility complex and the facility There is a disadvantage of being large in scale.

An object of the present invention is to provide an automatic welding apparatus using an infrared sensor that can perform welding while easily tracking a welding line in a non-contact manner while having a simple structure to improve the above problems.

In order to achieve the above object, an automatic welding apparatus using an infrared sensor according to the present invention is an automatic welding apparatus for welding while tracking a welding line between metal plates to be welded by transferring a welding torch mounted on a support arm of the transfer apparatus, first and second infrared sensors mounted on a support arm at a distance symmetrical to the center of the welding torch to detect infrared signals radiated from the metal plates to be welded in response to a temperature generated by heating during welding; and a controller for controlling the transfer device so that the welding torch is transferred so that the transfer device is transferred along a set travel path, but the output signal of the first and second infrared sensors is compared to attenuate a mutual error.

According to an aspect of the present invention, the transport device includes a carriage device installed so as to move forward and backward along a rail formed in a first direction with respect to a first stage on which the metal plate to be welded is placed, and the support arm includes the Doedoe coupled to the carriage device is installed to be transported in a second direction perpendicular to the first direction.

Preferably, each of the first and second infrared sensors is mounted on the housing so as to be dissipated through a housing coupled to the support arm, and is directed into the housing for heat dissipation of the first and second infrared sensors. A sensor cooling device installed to circulately supply cooling water; is further provided.

In addition, an air injector having an air ejection pipe mounted on the housing to eject air in a direction opposite to the light receiving surfaces of the first and second infrared sensors is further provided.

More preferably, a first amplifier for amplifying a signal output from each of the infrared sensors; a filter for filtering noise included in the signal output from the first amplifier; and a second amplifier amplifying the signal output through the filter and outputting the amplified signal to the controller.

According to the automatic welding apparatus using an infrared sensor according to the present invention, it is possible to control the welding torch to follow the gap by detecting infrared rays emitted from the metal plate to be welded by the heat generated during welding, so that the structure is simple and the welding line is easy to trace. it works

In addition, there is an effect that even beginners can easily weld regardless of the skill level of the user by using the sensor.

1 is a perspective view schematically showing an automatic welding apparatus using an infrared sensor according to the present invention.
FIG. 2 is an enlarged perspective view showing an enlarged view of a portion of an element mounted on the support arm of FIG. 1 .
3 is a block diagram of an automatic welding apparatus using the infrared sensor of FIG. 1 .
4 is a block diagram illustrating an example of the controller of FIG. 3 .
5 is a block diagram showing an example of the configuration of the computer of FIG.
6 is a view showing an example of a main screen displayed through a display device by the execution of the welding executor of the computer of FIG. 5 .

The present invention described below can apply various transformations and can have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Also, terms such as first, second, etc. may be used to distinguish and describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

In addition, when at least two different embodiments are described in the present application, all or part of the components may be used by merging and mixing with each other even if there is no particular description within the scope not departing from the technical spirit of the present invention. .

Hereinafter, an automatic welding apparatus using an infrared sensor according to a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a perspective view schematically showing an automatic welding apparatus using an infrared sensor according to the present invention, and FIG. 2 is a block diagram of the automatic welding apparatus using the infrared sensor of FIG. 1 .

1 and 2 , the automatic welding apparatus 100 using an infrared sensor includes a carriage apparatus 110 , a welding torch 131 , first and second infrared sensors 151 and 156 , and a controller 180 . to provide

The carriage device 110 is applied as an example of a transport device, and can travel along the rail 103 in the first direction, the X-direction.

The support arm 112 extending from the carriage device 110 along the Y direction perpendicular to the first direction is installed so as to be transportable from the carriage device 110 along the Y direction perpendicular to the traveling direction of the carriage device 110 . has been

The carriage device 110 is driven by the first motor 117 as a driving source, and the support arm 112 is moved by the second motor 118 . A power transmission structure from the rotation shaft of the first motor 117 to the wheels of the carriage device 110 and a rotation-linear power conversion transmission structure from the rotation shaft of the second motor 118 to the support arm 112 are variously known. Therefore, detailed description is omitted.

The carriage driving unit 116 controls driving of the first motor 117 and the second motor 118 according to a control signal output from the controller 180 .

The encoder 119 detects the rotation speed of the first motor 117 and outputs it to the controller 180 .

In the support arm 112, the first and the second in the bottom of the housings 141 and 146 installed at a distance symmetrical to each other about the welding torch 131 along the Y direction perpendicular to the traveling direction of the carriage device 110, respectively. 2 infrared sensors 151 and 156 are mounted.

The first and second infrared sensors 151 and 156 are installed in the housings 141 and 146 so that the light receiving window faces and is exposed to the first stage 105 on which the processing target metal plates 230 and 240 are seated. desirable.

In the housings 141 and 146 in which the first and second infrared sensors 151 and 156 are mounted, the operating temperature of the first and second infrared sensors 151 and 156 increases due to high heat generated during welding. The first and second infrared sensors 151 and 156 mounted so as to suppress the heat dissipation to provide a constant operating temperature have a cooling water inlet and outlet pipe in which a path is formed through which the cooling water for heat dissipation can enter and exit. Reference numerals 201a and 206a denote cooling water inlet pipes connected to allow the cooling water transferred from the sensor cooling device 200 for circulating and supplying cooling water to be introduced into the cooling water inlet and outlet pipes formed to lead into the housings 141 and 146, and reference numeral 201b , 206b is a cooling water discharge pipe for transferring the cooling water passing through the cooling water inlet/outlet pipe of the housings 151 and 156 to the sensor cooling device 200 .

The housings 141 and 146 may be formed of a metal material having good heat dissipation properties.

The sensor cooling device 200 may be constructed to circulate and supply cooling water into the housing through a cooling water inlet pipe and a cooling water discharge pipe.

The type, flow rate, etc. of the cooling water applied to the sensor cooling device 200 may be applied so that the infrared sensors 151 and 156 can be maintained at an appropriate temperature, for example, room temperature, depending on the applied device.

The air injector 210 sprays air in a direction opposite to the light receiving surface in order to suppress the smoke generated during welding from blocking the temperature detection target area of the first and second infrared sensors 151 and 156. It may be installed, and in the illustrated example, an air injection pipe 216 for ejecting air generated and sent from the air injector 210 is coupled to the housing 146 . Although the first infrared sensor 151 is mounted on the housing 141 is also hidden from view, the air injection pipe is mounted.

Since the infrared sensors 151 and 156 have a fast response speed and a non-contact type, restrictions on distance separation are alleviated, and preparation work before measurement is simple. In addition, the transmittance is good in a wide wavelength band.

Each of these infrared sensors 151 and 156 detects infrared rays radiated corresponding to the temperature change of the metal plates 230 and 240 to be welded by heating by heat generated during welding of the metal plates 230 and 240 to be welded. and output a voltage signal corresponding to the detected signal.

Preferably, the changes in voltage and current output corresponding to the infrared rays received from the infrared sensors 151 and 156 may be very weak, so that noise can be removed while increasing the sensitivity. For this purpose, it is preferable to further apply the first amplifiers 153 and 157, the bandpass filter (BPF) 154 and 158, and the second amplifiers 155 and 159.

The first amplifiers 153 and 157 amplify the signals output from the corresponding infrared sensors 151 and 156 .

The band pass filters 154 and 158 are applied as an example of a filter for removing noise. Preferably, the filtering band is set to remove the AC power noise in the 60Hz band and to remove unnecessary noise generated during welding. desirable. Unlike the illustrated example, a low-pass filter may be applied instead of the band-pass filters 154 and 158 .

The second amplifiers 154 and 159 amplify and output the signal output through the band pass filters 154 and 158 to an appropriate value required by the controller 180 .

The controller 180 controls driving of the carriage device 110 , the welding machine 130 , the air sprayer 210 , and the sensor cooling device 200 . Unlike the illustrated example, of course, the air injector 210 and the sensor cooling device 200 may be constructed to be manually operated.

The controller 180 detects the carriage device 110 from the first and second infrared sensors 151 and 156 while driving the carriage device 110 in the first direction according to the set travel distance and travel speed during welding. By using the input signal, the transfer of the support arm 112 in the y-axis direction is controlled so that the difference between the temperatures detected for each of the metal plates 230 and 240 to be welded is reduced.

That is, when welding is performed by the welding torch 131, when the tip tip of the welding torch 131 is located in the center of the gap between the welding target surfaces of the metal plates 230 and 240 to be welded, a plurality of concentrically shown in FIG. As indicated by a dotted line with a circular orbit of , the temperature is symmetrically distributed around the current welding point. On the other hand, if the welding torch 131 is deviated from the center of the welding line to either side along the Y direction, the current welding point As a reference, the temperature distribution on the temperature detection target region of each of the welding target metal plates 230 and 240 is changed. Therefore, if the welding torch 131 is controlled to be transferred left and right along the Y direction so that the temperature difference corresponding to the signal output from each of the infrared sensors 151 and 156 is reduced, accurate tracking of the welding line can be achieved. That is, when the output signal of any one of the infrared sensors 151 and 156 is greater than the output signal of the other infrared sensors 156 and 151, the infrared sensors 151 and 156 in which the welding torch 131 generates a large output signal. ), the support arm 112 is transferred so that the welding torch 131 is transferred toward the infrared sensors 156 and 151 that output a small output signal by determining that they are separated along the Y direction.

The controller 180 is preferably built with a general computer. In this case, as shown in FIG. 4 , a DAQ (Data Acquisition Device) 181 is applied as a relay device that relays data conversion and acquisition between the computer 190 and the carriage driving unit 116 and other devices.

The DAQ 181 samples the signals output through the second amplifiers 154 and 159, converts them into digital signals, and transfers the control signals output from the computer 190 for driving control of the carriage device 110 to the carriage. It may be constructed so as to process the conversion corresponding to the driving unit 116 .

In addition, as shown in FIG. 5 , the computer 190 includes a central processing unit (CPU) 191 , a ROM 912 , a RAM 193 , and a display device 194 , which are typical components. , an input device 195 , a storage device 196 , and a communication device 199 .

The storage device 196 is preferably a flash disk that is stable against vibration.

A welding executor 197 is installed in the storage device 196 as an execution program for controlling each element and processing the acquired data in addition to the operating program.

The welding executor 197 sets the traveling speed, the traveling distance, the weaving width, and the weaving speed of the carriage device 110 during welding, and the temperature detected through the infrared sensors 151 and 156 and the current of the welding torch 131 . It may be constructed to display and store location values, etc.

Reference numeral 198 denotes a sensor output value according to a separation distance from a detection target area, that is, a welding target metal plate 230 and 240 in order to calculate a temperature value corresponding to a signal output from the infrared sensors 151 and 156 and received. It is a lookup table in which the corresponding temperature values are experimentally obtained and recorded.

An example of the main screen provided through the display device 194 by the execution of the welding executor 197 is shown in FIG. 4 .

In the main screen 270, reference numeral 271 denotes a window showing the current temperature values measured by the infrared sensor 151 and 156 and the values acquired according to the driving distance of the welding torch 131 as a graph. , and reference numeral 275 denotes a transfer operation key window that can be used to manually transfer the welding torch 131 . The key provided in the window indicated by reference numeral 276 is provided with keys for manual operation when moving left and right along the Y direction orthogonal to the traveling direction of the carriage device 110, and the key marked "Set Zero" ( 277) is used to set the current position as the starting point of the zero point.

In addition, in the window indicated by the reference numeral 278, keys for manually operating the forward and backward movement along the X direction, which is the traveling direction of the carriage device 110, are provided, and the key 279 indicated by "Set Zero" is the current This is used when you want to set the position as the starting point of the zero point.

The monitoring window 281 provides data acquisition time, coordinates, and temperature values displayed in text. In the monitoring window 281 , the value indicated by Axis 1 is a position value against the traveling direction of the carriage device 110 , and the value indicated by Axis 2 is the value indicated by the welding torch 131 moving in the Y direction.

It is a window displaying the coordinate values of the time, Temperature R is a temperature value detected through the first infrared sensor 151, Temperature L is a temperature value detected through the second infrared sensor 156, respectively.

In the lower right corner, various keys are provided to set the welding speed, movement distance, weaving speed and weaving width, and whether or not to store the acquired data and the method. Reference numeral 287 denotes a key corresponding to driving start.

By using such a device, welding conditions, for example, traveling speed, weaving width, travel distance are set, the welding torch 131 is adjusted to be transferred to the initial welding line position, the zero point is set, and then the "weaving key 287 is operated" The support arm 112 reduces the temperature difference between the metal plates 230 and 240 to be welded by using the signal input from the infrared sensors 151 and 156 while driving the carriage device 110 in the first direction under the set condition. ) is transferred in the Y-axis direction while welding is performed.

On the other hand, the embodiments disclosed in the drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

110: carriage device 131: welding torch
151: first infrared sensor 156: second infrared sensor
180: controller

Claims (1)

An automatic welding device for welding while tracking a welding line between metal plates to be welded by transporting a welding torch mounted on a support arm of a transport device,
first and second infrared sensors mounted on the support arm at a distance symmetrical about the welding torch to detect infrared signals radiated from the metal plates to be welded in response to a temperature generated by heating during welding;
A controller for controlling the transfer device so that the welding torch is transferred so that the transfer device is transferred along a set travel path, but the output signal of the first and second infrared sensors is compared to attenuate a mutual error; and
The transfer device
and a carriage device installed so as to move forward and backward along the rail formed in the first direction with respect to the first stage on which the metal plate to be welded is placed;
The support arm is coupled to the carriage device and is installed to be transported in a second direction perpendicular to the first direction,
Each of the first and second infrared sensors is mounted on the housing so that heat can be dissipated through the housing coupled to the support arm,
The automatic welding apparatus using an infrared sensor, characterized in that for heat dissipation of the first and second infrared sensors, a sensor cooling device installed to circulately supply cooling water to the inside of the housing is provided.

Images