KR100671022B1 - Method for inspecting the image condition of welding robot by using laser vision sensor - Google Patents

Abstract

The present invention relates to a welding robot image state checking method using a laser vision sensor. In the welding robot image state checking method using the laser vision sensor according to the present invention, the laser band sensor in the normal state is set from the image data photographed using the laser vision sensor. Moving the welding robot to the set position; calculating the area value of the current laser stripe from the current image data measured at the position; and comparing the size of the current laser stripe area value with the laser stripe area value at a steady state. And determining whether or not the welding operation of the welding robot having the laser vision sensor is performed based on the comparison between the step and the laser strip area value.

Welding robot, laser vision sensor, image data, laser strip

Description

Method for inspecting the image condition of welding robot by using laser vision sensor}

1 is a schematic view showing a welding robot weaving system according to the prior art.

Figure 2 is a schematic diagram showing a welding robot image state checking system according to an embodiment of the present invention.

3 is a flow chart illustrating a procedure for performing robot image welding by using a laser vision sensor according to an exemplary embodiment of the present invention.

Figure 4 is an exemplary screen showing image data photographing the laser strip of the laser vision sensor according to an embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

210... Robot control unit 211. Processor

212... Timer 213... Memory

214... Area calculating section 215... Robot drive unit

220... Sensor control unit 222. Sensor drive

224... Image processing unit 230. Welding robot

231... Welding torch 240... Laser vision sensor

250... Welded object

The present invention relates to a method and system for checking a welding robot image condition using a laser vision sensor.

In general, the welding robot is used in the joining process of the metal plate, such as automobiles, ships, etc., the welding operation is automatically performed by the work program. The welding robot performs welding while following the welding line of the welded object by using a welding torch attached to the robot arm according to a work instruction.

In the weaving system of the conventional welding robot, the invention in which the 3D coordinates and the weaving coordinates of the welding line are obtained from the image data obtained from the laser vision sensor and the welding robot is driven based on the weaving coordinates. to be. Application No. 10-1977-0042128, filed Aug. 28, 1997, entitled "Control Methods and Apparatus for Welding Robots Using Laser Vision Sensors" (hereinafter referred to as prior invention), issued Mar. 15, 1999. Is disclosed.

1 is a configuration diagram schematically showing a welding robot weaving system according to the prior art.

Referring to FIG. 1, a weaving system of a welding robot using a laser vision sensor may be largely divided into a robot controller 210 and a sensor controller 220. In addition, the weaving system of the welding robot 30 is composed of a welding robot 30 under the control of the robot control unit 210, the laser vision sensor 40 under the control from the sensor control unit 220.

The robot controller 210 includes a processor 11 for controlling the welding robot 30 and a timer 12 for periodic control of the welding robot 30. In addition, the robot controller 210 stores an execution program for controlling the welding robot 30 and information to be processed during execution of the program.

The sensor controller 220 adjusts the weld line coordinates from the sensor driver 21 for driving the laser vision sensor 40, the image processor 22 for processing the image data obtained from the laser vision sensor 40, and the processed image. It consists of the coordinate conversion part 23 for obtaining.

The biggest problem of the welding robot with such a conventional laser vision sensor is that the welding robot is highly dependent on the laser vision sensor when welding. This prevents the welding robot from performing accurate image processing while continuing to work with an image state that is soiled with fume or spatter. This not only makes the actual measurement information inconsistent with the processed information, but also reduces the reliability of the data provided by the laser vision sensor. As a result, the accumulation of these conditions can lead to problems that not only reduce work efficiency and quality, but also make work difficult.

The present invention is to solve the above problems, an object of the present invention is to calculate the current laser band area value taken from the laser vision sensor compared to the laser band area value of the normal state set whether the abnormal state of the image; It is to provide a welding robot image condition checking system and method that can determine.

It is another object of the present invention to provide a welding robot image condition checking system and method that can interrupt the welding operation of a welding robot when an area loss occurs by a certain ratio or more than the laser band area value set in the normal state. To provide.

In order to achieve the above objects, according to an aspect of the present invention, the step of setting the laser band area value in the steady state from the image data photographed using the laser vision sensor, the area value of the laser band in the steady state Moving the welding robot to a position where the position is set; calculating an area value of the current laser stripe from the current image data measured at the position; A method for checking a welding robot image state using a laser vision sensor, the method comprising: comparing a size and determining whether a welding operation of a welding robot having a laser vision sensor is performed based on a comparison of the laser band area values is provided. Can be.

In a preferred embodiment, when the current laser stripe area value is smaller than the laser stripe area value in the normal state, the welding robot stops the welding operation or generates an alarm alarm under the control of the robot controller. Can be.

Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a schematic diagram showing a welding robot image state checking system according to an embodiment of the present invention.

Referring to FIG. 2, the welding robot image state system according to the present invention includes a laser control system including a robot controller 210, a welding robot 230, a sensor controller 220, and a laser vision sensor 240. .

The robot controller 210 includes a timer 212, a memory 213, an area calculator 214, a robot driver 215, and a processor 211. The timer 212 includes a function of transmitting a counting completion signal whenever a set time arrives. In addition, the robot controller 210 may further include a function of calculating the weaving coordinates of the welding of the welding torch 231 from the image data measured by the laser vision sensor 240 and controlling the operation of the welding robot 230. have.

The memory 213 includes a function of storing the center point coordinates of a specific welding line in order to move the welding robot 230 to the position where the laser band was measured in the normal state. The memory 213 further includes a function of storing the laser band area value of the steady state and the laser band area value of the current image state calculated by the area calculator 214.

The area calculator 214 includes a function of measuring a laser band area value of an image state provided from the sensor controller 220. The laser stripe area value measured by the area calculator 214 may be transmitted to the processor 211 and used to compare the laser stripe area values according to the present invention.

The robot driver 215 includes a function of driving the welding robot 230 according to the instruction of the processor 211. In addition, the robot driver 215 may further include a function of moving the welding robot 230 to a position where the laser band is measured in the normal state by using a specific welding line coordinate stored in the memory when an abnormality related to the image state occurs. In addition, the robot driver 215 may further include a function of stopping the welding operation according to the instruction of the processor 211.

The processor 211 interlocks with the timer 212, the memory 213, the area calculator 214, and the robot driver 215, and senses a request signal for photographing a welded portion in response to the completion signal of the timer 212. It includes a function for transmitting to the control unit 220. In addition, when the welding robot 230 does not calculate the weld line coordinates from the image data measured by the laser vision sensor 240 during the welding operation, the laser band area value of the current image state calculated by the area calculator 214. It further includes the function of receiving a comparison with the laser strip area value of the steady state. In addition, the processor 211 further includes a function of instructing the robot driver 215 to stop work when the laser stripe area value of the current image state is smaller than the laser stripe area value set in the normal state when comparing the laser stripe area values. do.

The sensor controller 220 is interlocked with the robot controller 210 and the laser vision sensor 240, and includes a sensor driver 222, an image processor 224, and a coordinate converter 223. The sensor controller 220 drives the laser vision sensor 240 according to the welding line information request signal of the robot controller 210, receives the image data photographed by the laser vision sensor 240, and transmits the image data to the processor 211. To perform the function. Here, the laser vision sensor 240 performs a function of photographing a welded portion of the welded object according to the image data request signal of the sensor controller 220.

Referring to the welding robot image state inspection system according to an embodiment of the present invention shown in FIG. 2 schematically.

When the completion signal of the timer 212 is applied, the processor 211 transmits an image data request signal to the sensor driver 222. The sensor driver 222 may transmit an image data request signal to the laser vision sensor 240 to start capturing. The timer 212 may output a completion signal when a sampling time for finding the center of the weld line arrives from the image data photographed by the laser vision sensor.

The image processor 224 receives image data captured by the laser vision sensor 240 and transmits the image data to the area calculator 214 through the processor 211. The coordinate converter 223 calculates the coordinates of the weld line from the image processed by the image processor 224.

Thereafter, when the welding operation is performed, when the welding line coordinates cannot be calculated from the image data measured by the laser vision sensor 240, when the abnormality related to the image state occurs, the processor 211 may determine the normal state calculated from the area calculator 214. The size of the laser stripe area value and the laser stripe area value of the current image state can be compared. In addition, the processor 211 may determine whether the welding robot 230 is interrupted when the laser band area value is smaller than the laser band area value set in the normal state.

The laser vision sensor 240 is installed away from the welding torch 231 by a predetermined distance, which is to prevent the photographed image from being deteriorated by the flame of the welding torch 231. The laser vision sensor 240 photographs a welded portion of the welded object 250 according to a driving signal of the sensor driver 222 and transmits the image data to the image processor 224. The laser vision sensor 240 may photograph the center point of the weld line while moving along the weld line direction of the welded object 250.

3 is a flowchart illustrating a procedure of performing image state check by robot welding using a laser vision sensor according to an exemplary embodiment of the present invention.

Referring to FIG. 3, first, a robot controller of a welding robot image state checking system according to the present invention receives image data from a laser vision sensor through a sensor controller and sets a laser band area value in a normal state (step 301).

The robot controller moves the welding robot to the position where the laser band was measured in the normal state to measure the current image state (step 303). After the welding robot moves to a position for measuring current image data, the robot controller calculates a current laser stripe area value through an area calculator using the current image data captured by the laser vision sensor (step 305). .

Thereafter, the welding controller compares the current laser stripe area value calculated by the area calculator with the laser stripe area value set in the normal state to check the image state before proceeding the welding operation (step 307). When the current laser stripe area value is greater than or equal to the laser stripe area value set in the normal state, the welding operation may be performed by controlling the welding robot based on the image data provided through the sensor controller (step 309). Here, when the current laser stripe area value is smaller than the laser stripe area value set in the normal state, the robot control unit may stop the welding operation of the welding robot or generate an alarm alarm through the robot driving unit (step 311).

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During the operation of the welding robot, if the next laser band image is acquired, the process returns to the step 305 of calculating the current laser band area value, and may continue the welding operation.

4 is an exemplary view showing image data of photographing a laser strip of a laser vision sensor according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the illustrated screen is a screen showing a laser strip 401 in a normal state photographed by a laser vision sensor and a laser strip 403 in a current image state where an area loss occurs. The laser strip 401 in the steady state and the laser strip 403 in the current image state where the area loss occurs represent image data photographed at the same position for comparing the area values of the laser strips.

The area of the laser band 401 in the steady state and the laser band 403 in the current image state in which the area loss occurs are calculated by the area calculator.

The area value of the steady state laser strip 401 may be a reference for accurate image processing required for the welding operation. In addition, the robot controller may increase the reliability of the welding operation from the image state defect of the laser vision sensor by setting the area value of the laser strip 401 in the normal state.

The laser strip 403 in the current state where the area loss occurs is a laser vision sensor that receives the image data of the laser welded under the influence of arc, fume, spatter, etc. by welding. This can occur if normal image data cannot be obtained from the laser vision sensor during the unit time of.

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

According to the present invention, the present invention provides a welding robot image state checking system and method for determining an abnormal state of an image state by calculating a current laser band area value photographed from a laser vision sensor and comparing the laser band area value in a normal state. can do.

According to the present invention, when the current laser band area value is smaller than the laser band area value set in the normal state, it is possible to provide a welding robot image condition checking system and method capable of stopping the welding operation of the welding robot.

Claims (3)

Setting a laser band area value at a steady state from image data photographed using a laser vision sensor; Moving the welding robot to a position where the area value of the laser strip in the steady state is set; Calculating an area value of a current laser strip from the current image data measured at the position; Comparing the current laser stripe area value with a size of the laser stripe area value in the steady state; And Determining whether the welding operation of the welding robot including the laser vision sensor is in progress based on the comparison of the laser strip area values; Welding robot image state checking method using a laser vision sensor comprising a. The method of claim 1, When the current laser stripe area value is smaller than the laser stripe area value in the normal state, the welding robot stops the welding operation under the control of the robot control unit. . delete

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