KR100695939B1 - Method for operating the rotating arc welding with welding current data by rotating of welding torch - Google Patents

Abstract

A method for operating the rotating arc welding using welding current data per rotating positions of a welding torch is provided to conduct rotating arc welding in which welding torch positions and welding line tracking are corrected by detecting the welding current data per the rotating positions of the welding torch. A method for operating the rotating arc welding using welding current data per rotating positions of a welding torch comprises: a step(S401) of collecting welding current data according to rotating positions of the welding torch as well as rotating position data for representing rotating positions of a servo motor; a step(S405) of matching the welding current data with the rotating position data; a step(S407) of detecting welding current data per rotating positions of the welding torch using the welding current data and the rotating position data that are matched with; a step(S409) of calculating a horizontal correction value and a vertical correction value using the detected welding current data per the rotating positions of the welding torch; a step(S411) of providing a robot driving controller with the calculated horizontal correction value and the calculated vertical correction value to correct a welding torch elevation and welding line tracking; and a step(S413) of implementing rotating arc welding from the corrected welding torch elevation and the corrected welding line tracking.

Description

{Method for operating the rotating arc welding with welding current data by rotating of welding torch}

1 is a perspective view showing a working state of the high-speed rotary arc welding according to a preferred embodiment of the present invention.

Figure 2 is a block diagram schematically showing a high speed arc welding seam tracking system according to an embodiment of the present invention.

3 is a flow chart illustrating a procedure for performing high speed rotating arc welding by correcting weld torch height and weld line tracking in accordance with a preferred embodiment of the present invention.

Figures 4a and 4b is an exemplary view showing a high-speed rotating arc welding by correcting the height and weld line tracking of the welding torch according to a preferred embodiment of the present invention.

                    <Explanation of symbols for the main parts of the drawings>

201, 203... Weld member 205... Bead

207... Servo motor 209... Welding torch

211, 213... Gear device

The present invention relates to a rotating arc welding drive method using welding current data for each rotation position.

The general welding method refers to metallurgical joining by operation such as heating and pressurization such that an atomic bond between two kinds of solid materials of the same or different types is used, and examples thereof include arc welding, resistance welding, laser welding, and the like. There is a way.

Arc welding is a welding method using heat generation of an arc by arc discharge. Here, the arc welding refers to melting the surface of the base material and the welding part by using heat obtained by generating an arc between the base material to be welded and the welding rod, and then melting the metal of the welding rod to the welding part and joining each other. In the arc welding, a carbon electrode or a tungsten electrode may be used instead of the electrode.

On the other hand, when the welding power source connected to the appropriate welding circuit and the base material are slightly separated from each other, an intense arc is generated between the two electrodes, and the arc persists even if the distance is farther away. . This is a discharge phenomenon in the vapor of the gas and electrode material present between the two electrodes, and typically, sufficient electrons must be supplied and discharged from the cathode (-pole) for the discharge phenomenon to continue.

The potential difference between the electrodes in the arc is called an arc voltage, and the current flowing through the arc is called an arc current. In the case of arc welding, this is also called a welding current. The welding current may be sized by the current flowing to give heat required for welding, the plate thickness of the base metal, the type of welding, the number of layers, the root spacing, the diameter of the electrode, and the like.

In systems for manufacturing large steel structures, such as ship building, bridge construction, etc., arc welding using high speed rotation is used to connect two or more members. The high speed rotation arc welding is a method of welding while rotating the arc at high speed as the electrode nozzle of the welding torch is mechanically rotated. At this time, the high-speed rotation of the arc uniformly distributes the arc force and the heat of the arc in the melt can give a flat and wide penetration shape.

In recent years, the method of automatically tracking weld seams is an indispensable condition in welding automation. Here, the said weld seam tracking method means that the position and attitude | position of a welding torch go along with the said welding path suitably according to the arbitrary welding path. And even if the welding path to be welded is recognized in advance, thermal deformation of the base material occurs during the welding process, so that the path change occurs. Therefore, the change must be corrected in real time.

In the conventional welding method, the weaving motion method is used to recognize the position difference between the top and bottom surfaces in the fillet part welding, which is the welding extension of the bottom plate and the bottom plate. The welding line can be traced by controlling the position of the upper and lower surfaces to be constant in the specified weaving motion.

However, when the welding robot uses an analog control circuit according to the prior art to find the center of the welding line during the welding operation using the welding line path and the rotary welding torch, problems may occur in the calculation process of kinematics and inverse kinematics.

As described above, when there are a large number of motors of the welding robot to be controlled in the welding line tracking process of the high-speed rotating arc welding system using the control circuit according to the prior art, the welding line cannot be traced due to the inverse kinematics of the correction value. Had the problem of degrading the quality.

The present invention is to solve the above problems, an object of the present invention, unlike the conventional welding method is a rotational position that can recognize the position difference between the upper surface and the lower surface by the rotation drive without performing the artificial weaving motion It is to provide a rotation arc welding driving method using the star welding current data.

Another object of the present invention is to detect a welding current data for each rotation position of the welding torch rotation arc welding driving method using the welding current data for each rotation position to perform the rotation arc welding of the welding torch position and the welding line tracking is corrected By providing a trace of the weld line.

In order to achieve the above objects, according to an aspect of the present invention, collecting the welding current data according to the rotational position of the welding torch and the rotational position data indicating the rotational position of the servo motor, the welding current data and the rotational position Matching data, detecting welding current data for each rotation position of the welding torch using the matched welding current data and the rotation position data, and horizontally using the welding current data for each rotation position of the detected welding torch Calculating a correction value and a vertical correction value; Providing the calculated horizontal correction value and the vertical correction value to a robot drive controller to correct the height and weld line tracking of the weld torch and performing rotation arc welding from the height and weld line tracking of the corrected weld torch, The vertical correction value is based on the welding current data for each rotation position of the welding torch through {(upper region welding current value + lower region welding current value) / 2-welding torch reference current value} * through a vertical correction gain value (Gain) The horizontal correction value is calculated by the formula of (upper region welding current value-lower region welding current value average) * horizontal correction gain value (Gain) using the welding current data for each rotation position of the welding torch. And the upper region welding current value and the lower region welding current value correspond to a position symmetrical with respect to the rotational position of the welding torch. Value, and the welding torch reference current value is a reference value for height control of the welding torch, and the vertical correction gain value and the horizontal correction gain value are tuning values adjusted for stable arc welding. It is possible to provide a rotating arc welding drive method using the welding current data.

In a preferred embodiment, in the matching of the welding current data and the rotation position data, the welding current data may be characterized by minimizing the influence due to noise through Kalman filtering.

The rotation position data may be calculated using a signal converter that recognizes a point in time at which a reference position output signal (phase Z) output from the encoder of the servo motor for each rotation of the servo motor is output. can do. The welding current data may be current data measured according to the rotational position of the welding torch through the hall sensor.

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

In the following description of the present invention, if it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, the terms to be described later are terms set in consideration of functions in the present invention, and these terms may vary according to the intention or custom of the producer producing the product, and the definition of the terms should be made based on the contents throughout the present specification.

1 is a perspective view showing a working state of the high-speed rotary arc welding according to a preferred embodiment of the present invention.

Referring to FIG. 1, in the case of high speed arc welding of two welding members 201 and 203, the welding torch 209 is interlocked with the servo motor 207 and a predetermined gear device 211 and 213 to provide the two welding members 201 and 203. A bead 205 is formed along the weld line of the fillet joint to which the welding members 201 and 203 are coupled.

The welding torch 209 engages with the rotation of the servo motor 207 to perform rotation welding according to a command of a welding robot controller (not shown) that controls the operation of the high speed rotation arc welding. The welding torch also rotates from a minimum of 1 Hz to a maximum of 50 Hz. The shape of the bead is changed according to the number of revolutions. In general, the higher the speed, the more flat beads can be obtained, but the welding speed can be welded using an appropriate number of revolutions in terms of welding stability and arc control.

The servo motor 207 includes an encoder (not shown) of a line drive method. The encoder may output a reference position output signal providing reference position information of the rotating servo motor 207 to provide rotation position information for use of the rotating arc sensor device according to the present invention.

Figure 2 is a block diagram schematically showing a high-speed rotating arc welding seam tracking system according to an embodiment of the present invention.

1 and 2, the high-speed rotating arc welding seam tracking system 300 according to the present invention is an encoder 310, a signal converter 311, a servo motor 320, a hall sensor 330, a rotating arc sensor device Apparatus 340 and robot drive controller 350 are included.

The encoder 310 includes a function of providing a reference position output signal output every one revolution of the servo motor 320 to the rotating arc sensor device device 340 according to the present invention.

In the case of the reference position output signal coming out of the encoder, a problem arises in that the output signal is shorter during high-speed rotation, so that the output signal is missed and cannot be processed. In order to solve this problem, the signal converter 311 includes an encoder 310. When the reference position output signal is outputted from the reference position output signal, the time point at which the reference position output signal is output is recognized as a peak point, and the peak position is delayed so that the end 209 of the welding torch rotates the rotation position 214. It converts the signal into a transformed peak signal that can detect.

Here, the reference position output signal output from the encoder 310 is the pulse interval varies depending on the speed, in the case of high-speed rotating arc welding is output at a very short interval.

The hall sensor 330 measures a welding current output according to a rotational position of the welding torch, which is controlled and operated by the robot driving controller 350 during the high speed rotation arc welding. The measured welding current may be processed into a digital signal and transmitted to the rotating arc sensor device device 340 according to the present invention. At this time, the digital signal-processed welding current data is the shortest wire in two parts of the upper surface 215 which is the contact surface of the upper plate 201 of the welding member and the lower surface 216 which is the contact surface of the lower plate 203 while the welding torch rotates. Because of the length of the protrusion, two valleys and floors may appear.

The rotating arc sensor device device 340 includes a communication unit 341, an A / D data board 343, a central processing unit (CPU) 345, and a motion board 347 for motion control of the welding torch.

The communication unit 341 includes a function of connecting and transmitting the central processing unit 345 and the robot driving controller 350 to each other.

The A / D data board 343 collects the conversion peak signal converted from the signal converter 311 and the welding current data measured from the hall sensor 330 at the same time in real time to form a center for matching according to the present invention. And a function for transmitting to the processing device 345.

The CPU 345 may recognize a rotation position of the welding torch corresponding to the peak point of the conversion peak signal by using the input conversion peak signal and the welding current data. In addition, the central processing unit 345 calculates the rotation position data of the actual welding torch by applying an offset value to the rotation position of the welding torch corresponding to the recognized peak point.

Here, the offset value represents a difference between an initial position on the rotational trajectory of the welding torch and a reference point set as an absolute reference on the rotational trajectory of the welding torch.

In addition, the CPU 345 performs a function of matching the calculated rotation position data of the actual welding torch and the welding current data, and detecting welding current data for each rotation position of the welding torch through the matching. do. In this case, the welding current data is filtered through a Kalman filter and matched with the rotation position data.

In addition, the central processing unit 345 performs a function of instructing the robot drive controller 350 to perform a high speed arc welding along the welding line path input through the communication unit 341.

The motion board 347 includes a function of controlling the motion of the servo motor 320 driven during high speed arc welding.

The robot driving controller 350 performs a function of controlling the driving of the welding robot that performs the high-speed rotating arc welding according to the command of the central processing unit 345.

Figure 3 is a flow chart illustrating a procedure for performing a high speed rotating arc welding by correcting the welding torch height and weld line tracking according to a preferred embodiment of the present invention.

Referring to FIG. 3, the rotation arc sensor device according to the present invention first collects rotation position data indicating the rotation position of the servo motor and welding current data according to the rotation position of the welding torch from the hall sensor (S401). At this time, the collected welding current data is filtered through a filter of the Kalman technique reflecting the trend of the data trend (S403).

Thereafter, the rotating arc sensor device matches the filtered welding current data with the rotation position data (S405). In this case, the rotation position data may be shifted by an offset value to be matched by resetting the welding current according to the rotation position of the welding torch.

As described above, the offset value represents a difference between an initial position on the rotational trajectory of the welding torch and a reference point set as an absolute reference on the rotational trajectory of the welding torch.

Thereafter, the rotating arc sensor device detects welding current data for each rotation position of the welding torch (S407). Through the above process, the rotating arc sensor device matches the rotation position data and the welding current data, so that the welding current value in the up region, the welding current value in the down region, and the previous position are matched. The welding current value in the (Fore) region and the welding current value in the Rear region can be obtained.

Thereafter, the rotary arc sensor device that detects welding current data for each rotation position of the welding torch calculates a vertical correction value for height correction of the welding torch and a horizontal correction value for correction of the welding line tracking (S409). At this time, the horizontal correction value for the horizontal correction is for the problem of the centering (Centering) to accurately track the welding line for the rotation arc welding. Here, a detailed formula for the vertical correction value and the horizontal correction value will be described later.

Thereafter, the rotating arc sensor device provides the calculated vertical correction value and the horizontal correction value to the robot drive controller to perform welding line tracking correction and welding torch position correction for high speed rotation arc welding (S411).

The robot driving controller which has received the vertical correction value and the horizontal correction value corrects the height of the welding torch and the welding line tracking to perform rotating arc welding (S413). Thereafter, the method returns to step 401 after the rotating arc welding operation, and the rotating arc welding having excellent welding quality may be performed by repeatedly correcting the welding torch position and the welding line tracking.

Figures 4a and 4b is an exemplary view showing a high-speed rotating arc welding by correcting the height and weld line tracking of the welding torch according to a preferred embodiment of the present invention.

4A and 4B, the rotary arc sensor device according to the present invention in the rotary track 500 of the welding torch includes the up 501, the down 503, and the fore 505. Then, the welding current data in the position region of Rear 507 is detected.

This has a position difference of 25 each when the positional division data is 100 on the rotational track 500 of the welding torch. That is, when the position value of the lower 503 on the rotary track 500 is set to 0, the fore 505 is 25 and the up 501 is 50 along the rotational direction of the welding torch. (Rear) 507 is designated as a position value of 75.

Based on this, the rotating arc sensor device matches the rotation position data with the welding current data so that the welding current value in the up 501 region, the welding current value in the down 503 region, and fore The welding current value in the region 505 and the welding current value in the rear region 507 can be obtained.

As shown in FIG. 4B, the rotation arc sensor device according to the present invention calculates a vertical correction value 509 and a horizontal correction value 511 for welding torch height and welding line tracking. The vertical correction value 509 may be calculated through Equation 1 using welding current data 501, 503, 505, and 507 for each rotation position of the welding torch.

{(Upper zone welding current value + lower zone welding current value) / 2-welding torch reference current value} * Vertical correction gain value (Vain) = vertical correction value

Here, the welding torch reference current value is a reference value for height control of the welding torch, and is a current set to perform rotational arc welding from the ideal position of the welding torch to the fillet welding site where the two welding members 201 and 203 are coupled. Value.

Preferably, the welding torch reference current value uses an average value of the welding current value 505 in the fore region. The vertical correction gain value here is a tuning value that can be adjusted by the user.

In the case of rotating arc welding, the welding current value according to the welding torch is determined by the height of the welding torch so that the user can set the vertical correction gain value appropriate to the difference between the torch reference current value and the welding current data so that the arc can be stably generated. Can be induced.

In addition, the horizontal correction value 511 is also calculated through Equation 2 using the welding current data (501, 503, 505, 507) for each rotation position of the welding torch. The horizontal correction value 511 for tracking the weld seam is for the problem of centering to accurately track the seam for rotating arc welding.

(Upper Area Welding Current Value-Lower Area Welding Current Value) * Horizontal Correction Gain Value (Gain) = Horizontal Correction Value

The horizontal correction gain value may be set differently by the user in relation to the moving speed of the welding robot, the reaction time, and the noise level of the welding current data. Meanwhile, the horizontal correction gain value is also a tuning value that can be adjusted by the user.

In the rotating arc sensor device according to the present invention, more preferably, the linear control such as the horizontal correction may be performed, but the control may be limited to a predetermined value or more than a predetermined value of the horizontal correction value 511.

In this case, the restriction on the predetermined value or more of the horizontal correction value 511 makes the response to the abnormal value of the welding current data insensitive. In addition, the restriction on the fixed value of the horizontal correction value 511 or more is related to noise and stability of the system, and the sudden large response of the welding robot due to the predetermined value or more is directly connected to the welding failure.

As such, by rotating the welding torch position and the welding line tracking, the rotating arc welding method may prevent the bead 205 from being formed in the wrong direction when the welding members 201 and 203 are twisted. Since the formation of the upper and lower portions is controlled constantly, the bead quality can be improved through the formation of good beads. In addition, the rotating arc welding method can increase the time and efficiency of the arc welding by eliminating the teaching (Teaching) to perform the welding through the predetermined welding line.

The embodiments of the present invention have been described above with reference to the accompanying drawings. However, it is to be noted that the present invention is not limited to the above-described embodiments, and, as necessary, various modifications and changes can be made by those skilled in the art within the spirit and spirit of the appended claims.

According to the present invention, there is provided a rotating arc welding driving method using the welding current data for each rotation position to detect the welding current data for each rotation position of the welding torch and perform the rotation arc welding in which the welding torch position and the welding line tracking are corrected. You can trace the weld line.

Claims (4)

Collecting welding current data according to the rotational position of the welding torch and rotational position data representing the rotational position of the servo motor; Matching the welding current data with the rotation position data; Detecting welding current data for each rotation position of a welding torch using the matched welding current data and the rotation position data; Calculating a horizontal correction value and a vertical correction value using welding current data for each rotation position of the detected welding torch; Providing the calculated horizontal correction value and the vertical correction value to a robot drive controller to correct the height and weld line tracking of the weld torch and performing rotation arc welding from the height and weld line tracking of the corrected weld torch, The vertical correction value is based on the welding current data for each rotation position of the welding torch through {(upper region welding current value + lower region welding current value) / 2-welding torch reference current value} * through a vertical correction gain value (Gain) Is calculated, The horizontal correction value is calculated through the formula of (upper region welding current value average-lower region welding current value average) * horizontal correction gain value (Gain) using welding current data for each rotation position of the welding torch, The upper region welding current value and the lower region welding current value are welding current values corresponding to positions symmetrical with respect to the rotational position of the welding torch, and the welding torch reference current value is a reference value for height control of the welding torch, The vertical correction gain value and the horizontal correction gain value are tuning values adjusted for stable arc welding Rotating arc welding driving method using the welding current data for each rotation position, characterized in that. The method of claim 1, In the matching of the welding current data and the rotational position data, the welding current data is minimized due to noise through Kalman filtering. Rotating arc welding driving method using the welding current data for each rotation position, characterized in that. The method of claim 1, The rotation position data is calculated by using a signal conversion unit that recognizes the point of time when the reference position output signal (Z phase) output from the encoder of the servo motor for each rotation of the servo motor is output. Rotating arc welding driving method using the welding current data for each rotation position, characterized in that. The method of claim 1, The welding current data is current data measured according to the rotational position of the welding torch through the Hall sensor. Rotating arc welding driving method using the welding current data for each rotation position, characterized in that.

Images