JP5513206B2 - Method and apparatus for adjusting wire protrusion length of welding robot - Google Patents

Description

  The present invention relates to a method for adjusting a wire protrusion length of a welding robot in which an operation for adjusting the wire protrusion length of a welding wire protruding from the tip of a welding torch to a standard wire protrusion length is performed when detecting the position of a workpiece by a wire touch sensor. The present invention relates to a robot control device.

  In the field of welding, arc welding is widely used. The welding robot is provided with an electrode (contact tip) on the welding torch side at the tip of the welding torch and generates an arc having an arc length corresponding to the arc voltage applied between the welding torch side electrode and the workpiece. Is moved along the welding line to weld the workpiece.

  When performing a work welding operation using a welding robot, the position of the work is detected using a touch sensor for each welding operation. This is because the position of the workpiece at the start of welding, which has been taught in advance, is shifted from the position of the workpiece at the start of actual welding, and the position shift is corrected. For example, if the distance from the tip of the welding torch to the workpiece is detected by the touch sensor at the start of welding, and the detected actual distance deviates from the taught distance, the welding torch is adjusted so as to correct the deviation. It is moved in the direction approaching or moving away from the workpiece.

  The touch sensor detects the position of the workpiece (distance from the tip of the welding torch to the workpiece) as follows. That is, while applying a voltage between the welding torch side electrode and the workpiece, the welding robot arm is operated to move the welding torch in a direction approaching the workpiece, and the welding protruding from the welding torch side electrode at the tip of the welding torch Touch the wire to the workpiece. The contact of the welding wire with the workpiece is detected when the welding torch side electrode at the tip of the welding torch and the workpiece are short-circuited. As a result, the position of the welding torch tip at the start of movement and the position of the welding torch tip when the welding wire contacts the workpiece can be measured, and the distance from the welding torch tip to the workpiece can be obtained from the difference between the two positions. It is done. The position of the tip of the welding torch can be obtained by converting the rotation angle of each axis of the robot.

  When the touch sensor is used, it is necessary to adjust the protruding length of the welding wire protruding from the tip of the welding torch to a certain length, that is, the standard wire protruding length. This is because measurement by the touch sensor is performed under the condition that the welding wire protrusion length is the standard wire protrusion length. If the welding wire protrusion length deviates from the standard wire protrusion length, the touch sensor This is because an error occurs in the measured value.

  However, the protruding length of the welding wire varies at the end of welding, and deviates from the standard protruding length of the wire. Therefore, if the touch sensor is used for the next welding operation in the same state, an error occurs in the workpiece detection position.

  Therefore, in the prior art, as shown in Patent Documents 1, 2, and 3 below, every time one welding operation is completed, the welding wire is sent from the tip of the welding torch to a length longer than the standard wire protrusion length. The welding wire is cut by a wire cutting device (wire cutter), and the welding wire protruding length is adjusted to the standard wire protruding length.

Japanese Patent Laid-Open No. 7-232271 JP-A-7-284935 Japanese Patent Laid-Open No. 11-58012

  However, it takes a lot of operation time to cut the welding wire. Moreover, when the workpiece position detection by the wire touch sensor is repeatedly performed because there are many joints to be welded, it is necessary to repeat the welding wire cutting operation, and the operation time required for the welding wire cutting operation is enormous. The efficiency of the welding operation is reduced.

  The present invention has been made in view of such circumstances, and enables welding wire protrusion length to be adjusted to standard wire protrusion length when using a wire touch sensor without performing welding wire cutting work. It is an object to improve work efficiency.

The first invention is
A method for adjusting a wire protrusion length of a welding robot in which an operation of adjusting a wire protrusion length of a welding wire protruding from a tip of a welding torch to a standard wire protrusion length is performed when detecting the position of a workpiece by a wire touch sensor,
When detecting the position of the workpiece by the wire touch sensor,
The welding current is detected with the movement of the welding torch tip stopped,
Based on the difference between the detected welding current value and the welding current value when the distance from the welding torch tip to the workpiece becomes the standard wire projection length, the distance from the welding torch tip to the workpiece is calculated as the standard wire projection length. To obtain the required distance of the welding torch,
The welding torch is moved by the determined moving distance, and the distance from the welding torch tip to the workpiece is the standard wire protrusion length,
In this state, by sending the welding wire from the tip of the welding torch until it hits the workpiece,
The wire protrusion length is adjusted to the standard wire protrusion length.

The second invention is the first invention,
Detect welding current during crater processing at the end of welding operation
It is characterized by.

The third invention is the first invention,
The welding current is sampled during crater processing at the end of the welding operation to obtain an average value of the welding current, and the average value of the obtained welding current and the distance from the tip of the welding torch to the workpiece become the standard wire protrusion length. On the basis of the difference from the welding current value at that time, the moving distance of the welding torch required to make the distance from the welding torch tip to the workpiece the standard wire protrusion length is obtained.

The fourth invention is
In detecting the position of a workpiece by a wire touch sensor, in a wire protrusion length adjusting device for a welding robot in which an operation for adjusting the wire protrusion length of a welding wire protruding from the welding torch tip to a standard wire protrusion length is performed.
Welding torch moving means for moving the welding torch by driving a welding robot;
Voltage applying means for applying a voltage between the welding torch side electrode and a welding electrode made of a workpiece;
Welding current detecting means for detecting a welding current;
Welding wire feeding means for feeding the welding wire from the tip of the welding torch;
These welding torch moving means, voltage application means, welding current detection means, and control means for controlling the welding wire feeding means are provided, the control means,
When detecting the position of the workpiece by the wire touch sensor,
The welding current is detected with the movement of the welding torch tip stopped,
Based on the difference between the detected welding current value and the welding current value when the distance from the welding torch tip to the workpiece becomes the standard wire projection length, the distance from the welding torch tip to the workpiece is calculated as the standard wire projection length. To obtain the required distance of the welding torch,
The welding torch is moved by the determined moving distance, and the distance from the welding torch tip to the workpiece is the standard wire protrusion length,
In this state, by sending the welding wire from the tip of the welding torch until it hits the workpiece,
Control is performed to adjust the wire protrusion length to the standard wire protrusion length.

A fifth invention is the first invention,
With the voltage applied to the electrode on the welding torch side, the welding wire is fed out from the tip of the welding torch, and when the electrode on the welding torch side and the workpiece are short-circuited, it is determined that the welding wire has hit the workpiece, It is characterized by stopping feeding.

The sixth invention
A method for adjusting a wire protrusion length of a welding robot in which an operation of adjusting a wire protrusion length of a welding wire protruding from a tip of a welding torch to a standard wire protrusion length is performed when detecting the position of a workpiece by a wire touch sensor,
When detecting the position of the workpiece by the wire touch sensor,
Pull the welding wire into the welding torch so that it does not protrude at least from the tip of the welding torch,
In this state, move the welding torch toward the workpiece until the tip of the welding torch hits the workpiece,
Move the welding torch away from the workpiece until the distance between the welding torch tip and the workpiece reaches the standard wire protrusion length from the position where the welding torch tip hits the workpiece,
By sending out the welding wire from this welding torch tip until it hits the workpiece,
The wire protrusion length is adjusted to the standard wire protrusion length.

  According to the present invention, the welding wire protrusion length can be adjusted to the standard wire protrusion length when the wire touch sensor is used without performing the welding wire cutting operation. As a result, the efficiency of the welding operation is improved.

FIG. 1A is a diagram illustrating a control apparatus for a welding robot according to an embodiment, and FIG. 1B is a diagram illustrating an enlarged cross-section of a welding torch tip. FIG. 2 is a functional block diagram showing an internal configuration of the controller. FIG. 3 is a flowchart showing the processing procedure of the crater processing work program. FIG. 4 is a perspective view showing the crater process. FIG. 5 is a diagram showing the relationship between the distance between the welding torch side electrode and the workpiece and the welding current value at the time of crater processing, and is a diagram showing the contents of the distance / welding current value data stored in the storage unit. FIGS. 6A, 6 </ b> B, 6 </ b> C, and 6 </ b> D are diagrams showing the movement of the welding robot in time series when the crater processing operation program is executed. FIG. 7 is a diagram showing the relationship between the welding operation time and welding current. FIG. 8 is a flowchart showing the processing procedure of another embodiment. 9 (a), (b), (c), (d), (e), (f), (g), and (h) are diagrams showing the movement of the welding robot of another embodiment in time series. It is.

  Embodiments of a wire protrusion length adjusting method and apparatus for a welding robot according to the present invention will be described below with reference to the drawings.

  In the embodiment, a welding robot that performs arc welding work is assumed as the welding robot.

  FIG. 1 shows a control apparatus for a welding robot according to an embodiment. FIG. 2 shows an enlarged cross section of the tip of the welding torch.

  As shown in FIG. 1, the control device for the welding robot includes a welding robot 10 in which the axes 1 to 6 are driven so that the tip 17 a of the welding torch 17 moves along the welding line L, and power to the welding robot 10. , A welding power source device 20 that feeds the welding wire 21 and applies a voltage between the welding electrodes, and generates a drive command for driving the axes 1 to 6 of the welding robot 10 according to the input data. The controller 30 sends the generated drive command to the welding robot 10, controls each axis of the welding robot 10, and controls the feeding of the welding wire 21 and the voltage between the welding electrodes via the welding power source device 20. It is prepared for.

  The welding robot 10 has an arm 10a, and a welding torch 17 is attached to the tip of the arm 10a. The welding robot 10 is provided with a welding wire feeding device 18. A welding wire delivery unit 90 is provided outside the welding robot 10.

  The welding wire feeding device 18 and the welding wire feeding unit 90 constitute welding wire feeding means for feeding the welding wire 21 from the welding torch tip 17a.

  The welding wire 21 is accommodated in a reel shape in the welding wire delivery part 90. The welding wire feeding device 18 feeds the welding wire 21 from the welding wire feeding portion 90 and is welded by driving a wire feeding motor in accordance with a wire feeding speed command given from the controller 30 via the welding power source device 20. The tip of the torch 17 is fed to a welding torch side electrode (contact tip) 17b. The welding torch side electrode 17b and the workpiece W constitute a “welding electrode”.

  The welding power source device 20 constitutes a voltage applying means for applying a voltage between the welding torch side electrode 17b and the workpiece W.

  A voltage is applied between the welding electrodes in accordance with a voltage command given from the controller 30 via the welding power source device 20. As a result, arc discharge is generated between the welding torch tip 17a and the workpiece W, and the joint (joint) of the workpiece W is heated and melted by the heat generated by the arc discharge, and the welding wire 21 as a filler material is formed. Heated and melted, the welding wire 21 becomes a weld metal, and the joint portion of the workpiece W is joined.

  The welding robot 10 is a 6-axis work robot having axes 1, 2, 3, 4, 5, and 6, and includes a drive unit 19. The first axis 1, the second axis 2, and the third axis 3 are basic three axes, and the fourth axis 4, the fifth axis 5, and the sixth axis 6 are wrist three axes. The drive unit 19 includes a servo amplifier and a robot motor.

  The drive unit 19 constitutes welding torch moving means for driving the welding robot 10 to move the welding torch 17.

  The drive unit 19 drives each of the axes 1, 2, 3, 4, 5, 6 in accordance with a drive command for each axis angle given from the controller 30. By driving each of the shafts 1, 2, 3, 4, 5, and 6, the coordinate position P and the torch attitude angle of the tip 17a of the welding torch 17 are changed.

  FIG. 2 is a functional block diagram showing an internal configuration of the controller 30.

  As shown in FIG. 2, the controller 30 includes a teaching data input unit 31, a storage unit 32, a calculation unit 33, a welding power source data input unit 34, and an output unit 35.

  The teaching data input unit 31 includes a teaching operation panel 31a. When the teaching operation panel 31a is operated by an operator, teaching data and distance / welding current value data (FIG. 5) described later are input. The teaching data is data necessary for creating a work program for the welding robot 10, and the work program is created based on the teaching data. The work program includes a movement command and a work command for the welding robot 10. The work program includes a “crater processing work program” to be described later.

  In this embodiment, the position of the workpiece W is detected by a wire touch sensor (not shown) to adjust the height of the welding torch 17, and welding is started from the welding start point Ps as shown in FIG. A series of operations from the time when the welding torch 17 is moved to the welding end point Pe along L and the crater (recess) processing is performed in a state where the movement of the welding torch 17 is stopped is referred to as “welding operation”. . When one welding operation is completed, the next welding operation is performed. The “crater processing work program” describes a movement command and a work command when the crater processing is performed at the end of the welding work, and a movement command and a work command until the next welding work starts after the welding work is finished.

  In FIG. 2, the storage unit 32 stores a work program of the welding robot 10 and distance / welding current value data (FIG. 5).

  The welding power supply device 20 includes a current sensor 22 and a welding wire short-circuit detection circuit 23.

  The welding power source device 20 constitutes a welding current detection means for detecting the welding current I.

  The current sensor 22 detects the welding current I. The welding wire short-circuit detection circuit 23 detects that the current sensor 22 detects a short-circuit current, whereby the welding torch side electrode 17b and the workpiece W are short-circuited, that is, the welding wire 21 and the workpiece W are short-circuited (hereinafter referred to as welding wire). Short circuit).

  The welding current value I and the detection result of the welding wire short circuit detection circuit 23 are input to the welding power source data input unit 34.

  The output unit 35 includes a command value calculation unit 35a. The command value calculator 35a calculates the wire feed speed of the welding wire 21 and the voltage value between the welding torch side electrode 17b and the workpiece W based on the work program. Then, the output unit 35 outputs the calculated wire feed speed and voltage value to the welding power source apparatus 20 as a wire feed speed command and a voltage command, respectively.

  The calculation unit 33 includes a locus calculation unit 33a and each axis angle conversion unit 33b.

  The trajectory calculation unit 33a calculates the sequential movement target position P and the target torch attitude angle to which the welding torch tip 17a should move based on the work program.

  In each axis angle conversion unit 33b, the sequential movement target position P and the target torch posture angle of the tip 17a of the welding torch 17 of the welding robot 10 are the angles J1, 2, 3, 4, 5, 6 of the welding robot axes 1, Converted to J2, J3, J4, J5, and J6, respectively. A drive command for changing the welding robot axes 1, 2, 3, 4, 5, 6 to the target angles J1, J2, J3, J4, J5, J6 is generated. It is output to the servo amplifier of the drive unit 19.

  The calculation unit 33 is based on the welding current value data (FIG. 5) stored in the storage unit 32, the welding current value I input from the welding power source data input unit 34, and the detection result of the welding wire short circuit detection circuit 23. Then, a “crater processing work program” is executed in accordance with the processing procedure shown in FIG.

  That is, the controller 30 constitutes control means for controlling the welding torch moving means, the voltage applying means, the welding current detecting means, and the welding wire feeding means, and the movement described in the “crater processing work program”. The welding robot 10 is controlled according to the command and the work command.

  Hereinafter, processing contents when the crater processing work program is executed will be described.

  FIG. 4 is a perspective view showing the crater process.

  In FIG. 4, a state in which a structure of a T joint is manufactured by joining the two workpieces (both plate members) W <b> 1 and W <b> 2 serving as base materials by horizontal fillet welding by the welding robot 10 is illustrated. The tip 17a of the welding torch 17 moves from the welding start point Ps to the welding end point Pe along the direction of the welding line L corresponding to the joint of both workpieces (both plate members) W1 and W2, thereby forming a bead. The At the welding end point Pe, crater processing for filling the crater (recess) is performed in a state where the movement of the welding torch 17 in the direction of the welding line L is stopped. The crater process is performed for a predetermined time T. The welding wire 21 and the workpiece W are melted for a predetermined time T at a welding current value lower than that when the welding torch 17 is moved, so that the recess is filled. This is because crater cracking may occur when processing is performed at a high welding current value. When the crater process is completed, the molten pool is solidified and the depression is filled.

  In FIG. 4, the distance between the weld pool and the welding torch tip 17a when the welding torch tip 17a is stopped on the welding end point Pe is "the workpiece W (W1, W2) from the welding torch tip 17a during crater processing". Distance E ”.

  FIG. 5 is a diagram showing the relationship between the distance E between the welding torch tip 17a and the workpiece W and the welding current I during crater processing, and shows the contents of the distance / welding current value data stored in the storage unit 32. ing. In FIG. 5, the horizontal axis is the distance E between the welding torch tip 17 a and the workpiece W, and the vertical axis is the welding current value I.

  Between the distance E and the welding current value I, a relationship is established in which the welding current value I decreases in proportion to the distance E, as shown in FIG.

I = α · E + β (1)
It is assumed that the welding current value I when the distance E becomes the standard wire protrusion length Estd is Istd (= α · Estd + β).

  The standard wire protrusion length Estd and the welding current value Istd corresponding to the standard wire protrusion length Estd are given as constants (fixed values) and stored in the storage unit 32.

  The controller 30 executes the crater processing work program in accordance with the processing procedure shown in FIG.

  FIGS. 6A, 6 </ b> B, 6 </ b> C, and 6 </ b> D show the movement of the welding robot 10 during execution of the crater processing work program in time series. Hereinafter, a description will be given with reference to FIGS.

(Detection process of welding current I)
First, the welding current I is detected in a state where the movement of the welding torch tip 17a is stopped.

  In this embodiment, the welding current I is detected during the crater process at the end of the welding operation.

  FIG. 7 shows the relationship between the elapsed time during the welding operation and the welding current I. The crater process is performed at a relatively low welding current value over a predetermined time T.

  During the crater process, the welding torch tip 17a is stationary, and the distance from the welding torch tip 17a to the workpiece W is stable. Therefore, the welding current I and the distance E obtained from the welding current I can be calculated with high accuracy.

  During the crater process at the end of the welding operation, the welding current I is sampled at a predetermined period (for example, every 1 msec) for a predetermined time T (for example, 1 second) to obtain an average value Ia of the welding current I.

That is, the welding current I is taken in every predetermined cycle (step 101), and the taken welding current value I is expressed by the following equation (2):
.SIGMA.Ik (K = 1, 2,... M; where M is the number of welding currents taken)
The processing (step 102) for integrating at (10) is repeated until the crater processing is completed (step 103).

Until the crater process is completed, the welding current I is taken M times, and when the integration process of the welding current value I is completed (determination YES in step 103), then the following equation (3):
Ia = (ΣIk) / M (3)
Thus, the average value Ia of the welding current I during the crater process is calculated (step 104; FIG. 6A).

(Calculation processing of moving distance ΔE of welding torch 17)
Next, the difference between the calculated average value Ia of the welding current I and the welding current value Istd (= α · Estd + β) when the distance E from the welding torch tip 17a to the workpiece W becomes the standard wire protrusion length Estd. Based on this, the movement distance ΔE of the welding torch 17 necessary for setting the distance E from the welding torch tip 17a to the workpiece W to the standard wire protrusion length Estd is obtained.

That is, the equation (1) (I = α · E + β) stored in the storage unit 32 and the welding current value Istd (= α · Estd + β) when the standard wire protrusion length Estd is obtained and calculated in step 104 above. Based on the average value Ia of the welding current I during crater processing, the following equation (4):
ΔE = {Ia− (α · Estd + β)} / α (4)
Thus, the movement distance ΔE of the welding torch 17 is calculated (step 105).

(Moving process of welding torch 17)
Next, after the crater process is completed, that is, after the welding operation is completed, the welding torch 17 is moved by the movement distance ΔE calculated in step 105. In this case, the axes 1 to 6 of the welding robot 10 are driven to move the welding torch 17 in the longitudinal direction of the welding torch 17. As a result, the welding torch tip 17a is moved in the direction approaching or away from the workpiece W, and the distance E from the welding torch tip 17a to the workpiece W is set to the standard wire protrusion length Estd (step 106; FIG. 6 ( b)).

(Feeding process of welding wire 17)
Next, as shown in FIG. 6C, the welding wire 21 is sent out from the welding torch tip 17a in a state where the distance E from the welding torch tip 17a to the workpiece W is the standard wire protrusion length Estd. In this case, the welding wire 21 is sent out from the welding torch tip 17a in a state where a voltage is applied between the welding electrodes (step 107).

(Process to adjust wire protrusion length to standard wire protrusion length Estd)
Next, as shown in FIG. 6D, the welding wire 21 is fed out from the welding torch tip 17a until it abuts against the workpiece W, and the wire protruding length is adjusted to the standard wire protruding length Estd.

  That is, it is determined whether or not the welding wire 21 is short-circuited to the workpiece W while the welding wire 21 is being fed from the welding torch tip 17a in a state where a voltage is applied between the welding electrodes (step 108).

  If it is determined that the welding wire 21 is short-circuited to the workpiece W (YES in step 108), it is determined that the welding wire 21 has hit the workpiece W at that time, and the feeding of the welding wire 21 is stopped. As a result, the wire protrusion length becomes the standard wire protrusion length Estd (step 109).

  Thereafter, the position of the workpiece W is measured by the touch sensor in a state where the projection length of the welding wire 21 is the standard wire projection length Estd, and the next welding operation is performed.

  As described above, according to the present embodiment, the welding wire protrusion length can be adjusted to the standard wire protrusion length Estd when the wire touch sensor is used without performing the cutting operation of the welding wire 21. As a result, the efficiency of the welding operation is improved.

  In the above-described embodiment, the detection of the welding current I is performed during the crater process. However, this is an example, and the welding current I can be detected with the movement of the welding torch tip 17a stopped. If it exists, it may be other than during crater processing. For example, a series of processes such as detecting the welding current I shown in FIG. 3 may be executed immediately after the crater process and immediately before using the wire touch sensor.

  Next, another embodiment will be described.

  FIG. 8 is a flowchart showing the processing procedure of another embodiment.

  9 (a), (b), (c), (d), (e), (f), (g), and (h) show the movement of the welding robot 10 of another embodiment in time series. Hereinafter, description will be made with reference to FIGS. 8 and 9 together.

(Welding process of welding wire 21)
As shown in FIG. 9A, the welding wire 21 is drawn into the welding torch 17 so as not to protrude from the welding torch tip 17a. The welding wire 21 is pulled in by operating the welding wire feeding means (the welding wire feeding device 18 and the welding wire feeding unit 90) in the direction opposite to the feeding side. The welding wire 21 is drawn into the welding torch 17 so as not to protrude at least from the welding torch tip 17a (step 201; FIG. 9B).

(Moving process of welding torch 17 toward workpiece W)
Next, the axes 1 to 6 of the welding robot 10 are driven, and the welding torch tip 17a is moved in a direction approaching the workpiece W. In this case, the welding torch tip 17a is moved in a state where a voltage is applied between the welding electrodes (step 202; FIG. 9 (c)).

(Abutting processing of welding torch 17)
While the welding torch tip 17a is being moved while a voltage is applied between the welding electrodes, it is determined whether or not the welding torch side electrode 17b is short-circuited to the workpiece W (step 203).

  If it is determined that the welding torch side electrode 17b is short-circuited to the workpiece W (determination YES in step 203), it is determined that the welding torch tip 17a has hit the workpiece W at that time, and the movement of the welding torch tip 17a is stopped. (Step 204; FIG. 9D).

(Moving process of welding torch 17 away from workpiece W)
Next, the axes 1 to 6 of the welding robot 10 are driven to move the welding torch tip 17a away from the workpiece W (step 205; FIG. 9 (e)). In this case, the welding torch 17 is moved until the distance E between the welding torch tip 17a and the workpiece W reaches the standard wire protrusion length Estd, and when the distance E reaches the standard wire protrusion length Estd, the movement of the welding torch 17 is stopped. (Step 206; FIG. 9 (f)).

(Feeding process of welding wire 17)
Next, as shown in FIG. 9G, the welding wire 21 is sent out from the welding torch tip 17a in a state where the distance E from the welding torch tip 17a to the workpiece W is the standard wire protrusion length Estd. In this case, the welding wire 21 is sent out from the welding torch tip 17a in a state where a voltage is applied between the welding electrodes (step 207).

(Process to adjust wire protrusion length to standard wire protrusion length Estd)
Next, as shown in FIG. 9 (h), the welding wire 21 is fed out from the welding torch tip 17a until it abuts against the workpiece W, and the wire protrusion length is adjusted to the standard wire protrusion length Estd.

  That is, it is determined whether or not the welding wire 21 is short-circuited to the workpiece W while the welding wire 21 is being fed from the welding torch tip 17a in a state where a voltage is applied between the welding electrodes (step 208).

  If it is determined that the welding wire 21 is short-circuited to the workpiece W (determination YES in step 208), it is determined that the welding wire 21 has hit the workpiece W at that time, and the feeding of the welding wire 21 is stopped. As a result, the wire protrusion length becomes the standard wire protrusion length Estd (step 209).

  Thereafter, the position of the workpiece W is measured by the touch sensor in a state where the projection length of the welding wire 21 is the standard wire projection length Estd, and the next welding operation is performed.

  As described above, according to another embodiment, the welding wire protrusion length can be adjusted to the standard wire protrusion length Estd when the wire touch sensor is used without cutting the welding wire 21. As a result, the efficiency of the welding operation is improved.

  In another embodiment described above, the series of processes shown in FIG. 8 may be performed when the position of the workpiece W is detected by the wire touch sensor. For example, a series of processes shown in FIG. 8 can be executed immediately before using the wire touch sensor.

  In each of the above-described embodiments, it is determined that the short-circuit current is detected by the current sensor 22 that the welding torch tip 17a or the welding wire 21 has hit the workpiece W. However, this is merely an example. It may be determined that the welding torch tip 17a or the welding wire 21 hits the workpiece W by providing a shock sensor or the like and detecting an acceleration or the like when the welding torch tip 17a or the welding wire 21 hits the workpiece W.

  10 welding robot, 17 welding torch, 17a welding torch tip, 17b welding torch side electrode, 30 controller, W workpiece

Claims (5)

A method for adjusting a wire protrusion length of a welding robot in which an operation of adjusting a wire protrusion length of a welding wire protruding from a tip of a welding torch to a standard wire protrusion length is performed when detecting the position of a workpiece by a wire touch sensor,
When detecting the position of the workpiece by the wire touch sensor,
Detecting the welding current in a state where the welding torch tip stops moving in the longitudinal direction of the welding torch ;
Based on the difference between the detected welding current value and the welding current value when the distance from the welding torch tip to the workpiece becomes the standard wire projection length, the distance from the welding torch tip to the workpiece is calculated as the standard wire projection length. To obtain the required distance of the welding torch,
The welding torch is moved by the determined moving distance, and the distance from the welding torch tip to the workpiece is the standard wire protrusion length,
In this state, by sending the welding wire from the tip of the welding torch until it hits the workpiece,
A method for adjusting a wire protrusion length of a welding robot, wherein the wire protrusion length is adjusted to the standard wire protrusion length. Detect welding current during crater processing at the end of welding operation
The method of adjusting a wire protrusion length of a welding robot according to claim 1. The welding current is sampled during crater processing at the end of the welding operation to obtain an average value of the welding current, and the average value of the obtained welding current and the distance from the tip of the welding torch to the workpiece become the standard wire protrusion length. 2. The welding distance according to claim 1, wherein a moving distance of the welding torch necessary for making the distance from the tip of the welding torch to the workpiece the protrusion length of the standard wire is obtained based on a difference from the welding current value at the time. A method for adjusting the wire protrusion length of a robot. In detecting the position of a workpiece by a wire touch sensor, in a wire protrusion length adjusting device for a welding robot in which an operation for adjusting the wire protrusion length of a welding wire protruding from the welding torch tip to a standard wire protrusion length is performed.
Welding torch moving means for moving the welding torch by driving a welding robot;
Voltage applying means for applying a voltage between the welding torch side electrode and a welding electrode made of a workpiece;
Welding current detecting means for detecting a welding current;
Welding wire feeding means for feeding the welding wire from the tip of the welding torch;
These welding torch moving means, voltage application means, welding current detection means, and control means for controlling the welding wire feeding means are provided, the control means,
When detecting the position of the workpiece by the wire touch sensor,
Detecting the welding current in a state where the welding torch tip stops moving in the longitudinal direction of the welding torch ;
Based on the difference between the detected welding current value and the welding current value when the distance from the welding torch tip to the workpiece becomes the standard wire projection length, the distance from the welding torch tip to the workpiece is calculated as the standard wire projection length. To obtain the required distance of the welding torch,
The welding torch is moved by the determined moving distance, and the distance from the welding torch tip to the workpiece is the standard wire protrusion length,
In this state, by sending the welding wire from the tip of the welding torch until it hits the workpiece,
An apparatus for adjusting a wire protrusion length of a welding robot, wherein the wire protrusion length is controlled to be adjusted to the standard wire protrusion length. With the voltage applied between the welding electrodes, the welding wire is fed from the tip of the welding torch, and when the electrode on the welding torch side is short-circuited with the workpiece, the welding wire is judged to have hit the workpiece, and the welding wire is fed. The wire protrusion length adjusting device for a welding robot according to claim 4, wherein the apparatus is stopped.

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