JP3355243B2 - Torch position control method and control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which the tip of a consumable electrode (hereinafter, referred to as a wire) is brought into contact with an object to be welded (hereinafter, referred to as a work) before an arc is generated. Torch position control for detecting (hereinafter referred to as touch sensing), moving the welding torch (hereinafter referred to as torch) to the detected welding start position of the processing work, starting welding, and ending welding at a predetermined position. The present invention relates to a method and a control device.

[0002]

[Prior art]

[Prior Art 1] FIG. 1 is a block diagram of an automatic welding apparatus disclosed in Japanese Unexamined Patent Application Publication No. Sho 62-114771 of "Touch Sensing Loss Control Method for Welding Robot" (hereinafter referred to as Prior Art 1). is there.

In FIG. 1, reference numeral 1 denotes an automatic welding device, which includes a torch 4, a wire feeding device 6 for feeding a wire 5 to the torch 4, a power supply device 3 for feeding power to the wire 5,
And a control device 2 with a built-in microcomputer for comprehensively controlling the automatic welding device 1. The power supply device 3 includes a welding power supply device 3a, a detection auxiliary power supply device 3b, a contact current detection device 3c, and a detection / welding power supply switch 3d. An orthogonal coordinate system (hereinafter referred to as a reference rectangular coordinate system) XYZ including an X direction, a Y direction, and a Z direction having an origin at an arbitrary point near the workpiece 7 or near the wire tip 5a of the torch 4 is set. I do.

[0004] As shown in FIG.
The work 7 includes a welding line Wy including a welding start position A and a welding end position B, and a vertical surface 7a of the processing work.
And the horizontal surface 7b of the work for processing and the plate thickness surface 7 of the work for processing
c is three surfaces orthogonal to each other. Hereinafter, in the reference orthogonal coordinate system XYZ, the welding line direction is defined as the Y direction, the direction of the vertical surface 7a of the work is defined as the X direction, and the direction of the horizontal plane 7b of the work is defined as the Z direction.

FIG. 3 is a cross-sectional view of the tip of the torch at a predetermined wire protrusion length (hereinafter, referred to as a fixed wire length) Lt, and FIG. 4 is a sectional view of the torch tip at an actually changing wire protrusion length La. FIG.

As shown in the sectional views of the tip of the torch in FIGS. 3 and 4, the torch 4 has a shield gas nozzle (hereinafter, referred to as a nozzle) 4a and a through hole through which a wire 5 is inserted along the center line of the nozzle. The contact length of the wire from the tip of the contact tip 4b to the tip 5a of the wire (hereinafter referred to as a variable wire length) varies. This variable wire length is denoted by La.

As described above, the conventional control device 2 controls the TCP at the wire tip position (hereinafter referred to as a fixed tool point) with respect to the work 7 and the angle with respect to the work 7 when the fixed wire length Lt is limited. are doing. The position of the fixed tool point TCP is calculated from the shape and size of the mechanical component supporting the torch 4 and the predetermined position of the mechanical component supporting the torch 4.

For example, when the mechanical component supporting the torch 4 is an articulated robot, the shape and dimensions of the mechanical component are determined by the length of the link connecting the joints, The predetermined position of the component is determined by the output value of the encoder that detects the rotation angle of each joint. The position of the fixed tool point TCP can be calculated from the link size, the detected rotation angle of each joint, and the predetermined fixed wire length Lt.

In the conventional control device 2, the actual wire tip 5a coincides with the fixed tool point TCP only when the variable wire length La is equal to a predetermined fixed wire length Lt. Therefore, as described above, when the variable wire length La is equal to the fixed wire length Lt, if the control for moving the fixed tool point TCP to a predetermined position is performed, the control for moving the position of the wire tip 5a is performed. Become.

Before welding the processing work 7 shown in FIG. 2, coordinate values of predetermined positions of the teaching work 70 shown in FIGS. 5 to 8 are stored (hereinafter referred to as teaching). 5 to 8 are diagrams for explaining the work deviation amount calculation processing, and FIG. 5 is a diagram showing a teaching position and a detection position when the torch 4 is moved in the X direction and the Z direction. FIG.
FIG. 4 is a diagram illustrating a teaching position and a detection position when the torch 4 is moved in a Z direction and a Y direction. FIG. 7 is an explanatory diagram of a first conventional technique for calculating a work deviation amount which is detected by bringing a wire tip into contact with a work for processing. FIG.
FIG. 6 is a diagram showing a taught welding start position and a welding end position and a welding start position and a welding end position at the time of welding.

The teaching positions shown in FIGS. 5 and 7 are coordinate values (Xx0, Yx0, Zx) of the detection start position Px0 in the X direction.
0) and the coordinate value (Xz) of the detection start position Pz0 in the Z direction.
0, Yz0, Zz0). The teaching position shown in FIG.
The coordinate value (Xy0, Yy) of the detection start position Py0 in the Y direction
0, Zy0). 8 are coordinate values (Ax0, Ay0, Az0) of the welding start teaching position A0 and coordinate values (Bx0, By0, Bz) of the welding end teaching position B0.
0).

FIG. 9 is a flowchart for explaining the operation of the automatic welding apparatus shown in FIG. In the figure, the teaching procedure before the start of the process is the same as the teaching procedure of FIGS. 5 to 8, and two processes are performed next. The first process is a work shift amount calculation process (steps ST100 to ST300) for calculating the work position shift amount between the teaching position of the first teaching work and the actual position of the processing work thereafter. The second process is a torch position control process (step ST400) in which welding is performed after the torch whose displacement has been corrected is moved to the welding start position of the processing workpiece, and welding is completed at the welding end position.

First, the work shift amount calculation process as the first process is a work shift amount calculation process in the X direction (step ST1).
00) and Z-direction work deviation amount calculation processing (step ST2)
00) and Y-direction work deviation amount calculation processing (step ST3)
00).

FIG. 10 is a flowchart showing the operation sequence of the X-direction work deviation amount calculation processing. The operation of the X-direction work deviation amount calculation processing will be described with reference to FIG. First, as shown in FIG. 1, the detection / welding power supply switch 3d is switched to the detection auxiliary power supply 3b (step ST101).

In FIG. 8, the teaching work 70 includes a teaching welding line Wy0 consisting of a line connecting the welding start teaching position A0 and the welding end teaching position B0. As shown in FIGS. 5 and 6, the work 7 for processing is arranged at a position shifted from the work 70 for teaching, and forms a welding line Wy composed of a line connecting the welding start position A and the welding end position B. Contains. Further, assuming that the shift amount is ΔX in the X-axis direction, ΔY in the Y-axis direction, and ΔZ in the Z-axis direction, these shift amounts are calculated as follows.

First, the coordinate values (Xx0, Yx) of the taught X direction detection start position Px0 shown in FIGS.
The wire tip 5a is moved so that the fixed tool point TCP is located at (0, Zx0) (step ST10).
2). The wire tip 5 is detected by the detection auxiliary power supply 3b.
A voltage (hereinafter, referred to as a contact detection voltage) for detecting contact between the workpiece a and the work 7 is applied (step ST10).
3).

The wire tip 5a has a vertical surface 7
The torch 4 is moved in the X-axis direction until the contact current detecting device 3c detects the contact with the workpiece a, and the contact position with the work 7 (hereinafter referred to as the contact position of the work) P
The coordinate value (Xx1, Yx0, Zx0) of x1 is detected (steps ST104 to ST107). After the detection, the contact detection voltage is cut off (step ST10).
8).

A contact position (hereinafter referred to as a teaching work contact position) P at which the wire tip 5a contacts the teaching work 70.
Let the coordinate value of x2 be (Xx2, Yx0, Zx0). From the coordinate value of the work contact position Px1 for machining and the coordinate value Px2 of the contact position for teaching work, a work position deviation amount ΔX in the X-axis direction is calculated and stored by the following equation (1) (step ST109). . ΔX = Xx1-Xx2 (1)

FIG. 11 is a flowchart showing the operation sequence of the Z-direction work deviation amount calculation processing. The operation of the Z-direction work deviation amount calculation processing will be described with reference to FIG. The coordinate value (Xz0, Yz0, Zz0) of the taught detection start position Pz0 in the Z direction shown in FIG. 5 is shifted in the X direction by ΔX, and the coordinate value (Xz0) of the detection start position Pzs0 in the Z direction is shifted.
0 + ΔX, Yz0, Zz0) (step ST
201). The wire tip 5a is moved so that the fixed tool point TCP is located at the Z direction detection start position Pzs0 (step ST202).

A contact detection voltage is applied between the wire tip 5a and the work 7 by the detection auxiliary power supply 3b (step ST203).

The wire tip 5 is placed on the horizontal surface 7b of the processing work.
The torch 4 is moved in the Z-axis direction until the contact current detecting device 3c detects that the contact a has made contact with the contact position Pzs1.
(Xz0 + ΔX, Yz0, Zz1) are detected (steps ST204 to ST207). After the detection, the contact detection voltage is cut off (step ST20).
8).

The coordinate value (Xz0, Yz0, Zz) of the contact position of the teaching work 70 (hereinafter referred to as the teaching position) Pz2
2) and the coordinate value (Xz0) of the processing work contact position Pzs1.
+ ΔX, Yz0, Zz1), and calculates and stores the work displacement ΔZ in the Z-axis direction by the following equation (2) (step ST209). ΔZ = Zz1-Zz2 (2)

FIG. 12 is a flowchart showing the operation sequence of the Y-direction work deviation amount calculation processing. The operation of the Y-direction work deviation amount calculation processing will be described with reference to FIG. The coordinate values (Xy0, Yy0, Zy0) of the taught detection start position Py0 in the Y direction shown in FIG. 6 are shifted by ΔX in the X direction and ΔZ in the Z direction, and the coordinate values (Xy0 + ΔX) of the detection start position Pys0 in the Y direction are shifted. , Yy0, Zy0 + ΔZ) are calculated (step ST301). The wire tip 5a is moved so that the fixed tool point TCP is located at the Y direction detection start position Pys0 (step ST302).

A contact detection voltage is applied between the wire tip 5a and the work 7 by the detection auxiliary power supply 3b (step ST303). The torch 4 is moved in the Y-axis direction until the contact current detecting device 3c detects that the wire tip 5a has come into contact with the plate thickness surface 7c of the processing work, and the coordinate value (Xy0 + ΔX, Yy1,
Zy0 + ΔZ) is detected (steps ST304 to ST307). After the detection, the contact detection voltage is cut off (step ST308).

The coordinate value (Xy0, Yy) of the teaching position Py2
2, Zy0) and the coordinate value (Xy0 + ΔX, Yy1, Zy0 + ΔZ) of the work contact position Pys1 are calculated and stored according to the following equation (3) in the Y-axis direction (step ST309). ). ΔY = Yy1-Yy2 (3)

FIG. 13 is a flowchart showing the operation sequence of the torch position control process. The operation from the start to the end of the torch position control process will be described with reference to FIG. First,
The detection / welding power supply changeover switch 3d shown in FIG. 1 is switched to the welding power supply device 3a to connect the welding power supply between the wire 5 and the work 7 (step ST40).
1).

The teaching welding line Wy0 shown in FIG. 8 has a coordinate value (Ax0, Ay0, Az0) of the welding start teaching position A0 and a coordinate value (Bx1, By1, Bz) of the welding end teaching position B0.
1). The welding start teaching position A0 and the welding end teaching position B0 are calculated by a work deviation amount calculation process. The calculated shift amount of the work position (Δ
The coordinate values (Ax0 + ΔX, Ay0 + ΔY, Az0 + ΔZ) of the welding start position A shifted by X, ΔY, ΔZ) and the coordinate values (Bx1 + ΔX, By1 + ΔY,
Bz1 + ΔZ) (steps ST402 and ST403).

The torch 4 is moved to the calculated welding start position A to start welding, and welding is performed up to the welding end position B (step ST404).

In the prior art 1 described above, as described with reference to FIGS. 5 to 8, the coordinate values (Xz0, Yz0, Zz0) of the detection start position Pz0 in the Z direction are prevented in order to prevent a miss swing during touch sensing in the Y direction. ) Is shifted by ΔX to the coordinate value of Pzs0 (Xz0 + ΔX, Yz0, Zz0)
From the start, and the detection start position Py in the Y-axis direction
The coordinate value of Pys0 (Xy0 + ΔX, Yy0, Zy) obtained by shifting the coordinate value of X0 (Xy0, Yy0, Zy0) by ΔX
0) The coordinate value of Pys2 further shifted by ΔY (Xy
0 + ΔX, Yy0 + ΔY, Zy0).

[Prior Art 2] JP-A-62-142079
FIG. 1 shows a configuration diagram of a “work surface detection method in an automatic welding device” (hereinafter referred to as “prior art 2”) disclosed in
Is the same as FIG. 15 is an explanatory diagram of a work shift amount calculation process of the second conventional technique for detecting the tip of the contact tip by contacting the work for processing.

FIG. 14 is a flowchart for explaining the operation of the automatic welding apparatus according to the prior art 2. In the figure, the teaching procedure before the start of the process is the same as the teaching procedure of FIGS. 5 to 8, and the following four processes are performed from the start to the end of the process.

The first processing is performed by the wire feeding roller 6b.
Is reversed to draw the wire 5 into the contact tip 4b (step ST50). The second process is
Work shift amount calculation processing for calculating the work shift amount between the teaching position of the teaching work 70 and the actual position of the machining work 7 thereafter (steps ST100 to ST30)
0).

The third process is a process of rotating the wire feed roller 6b forward to take out the wire 5 from the contact tip 4b (step ST350). The fourth process is a process of calculating the welding start position A and the welding end position B of the processing work 7 in which the detected and calculated work deviation amount is corrected, and moving the torch 4 to the calculated welding start position A. Torch position control process (step ST40) for executing welding to start welding and performing welding to the calculated welding end position B.
0).

As described above, the prior art 1 performs the detection by bringing the wire tip 5a into contact as shown in FIG. 5, while the prior art 2 performs the contact as shown in FIG. The tip is brought into contact with the processing work 7 for detection. Therefore, the prior art 2 has a feature that it is not affected by the fluctuation of the wire protrusion length, in addition to the advantage of preventing the miss swing of the prior art 1. The second work deviation amount calculation process and the fourth torch position control process of the related art 2 are the same as the processes of the related art 1.

The prior art 2 has an advantage as compared with the prior art 1, but this advantage cannot be obtained unless the following three processes are performed, so that it takes a long time to perform the work shift amount calculation processing. . (1) Since the spatter adheres to the wire tip 5a or a molten ball is generated, the wire 5 is connected to the contact tip 4 at the time of detection.
If it cannot be pulled into b,
The tip of the wire 5 must be cut. (2) The contact tip 4b is brought into contact with an arbitrary horizontal plane of the work 7 vertically, the torch 4 is raised from the contact position by a distance corresponding to a predetermined fixed wire length Lt, and the wire 5 is turned into a work. It is necessary to accurately regulate the wire protrusion length to the length of the fixed wire length Lt by feeding the wire until it comes into contact with the horizontal surface 7b. (3) The contact tip 4b is attached to the torch 4 movably in the axial direction and pulled into the nozzle 4a during welding.
It is necessary to move toward the tip during touch sensing.

[PRIOR ART 3] FIG.
FIG. 1 is a diagram illustrating a configuration of a “sensing device using a welding wire” (hereinafter, referred to as conventional technology 3) disclosed in Japanese Patent No.

In the figure, the same functions as those in FIG. 1 showing the configuration of the automatic welding apparatus of the prior art 1 are denoted by the same names and symbols. However, a wire straightening gauge (hereinafter, referred to as a gauge) 8 which calculates and corrects a wire bending deviation amount ΔM and a wire bending amount (hereinafter, referred to as a bending amount) ΔR, which will be described later, 8
And a wire cutting device 9 for cutting the distal end of the wire 5.

FIG. 17 is a flowchart for explaining the operation of the automatic welding apparatus of the prior art 3. In this figure, the teaching procedure before the start of the processing is the same as the teaching procedure described with reference to FIGS.
Performs two processes.

The first process is a wire bending deviation amount calculating process for calculating an apparently reduced wire protrusion length (hereinafter referred to as a wire bending deviation amount) ΔM due to the bending of the wire, and a bending amount ΔR of the wire 5. This is a wire bending calculation and correction process (step ST1) for executing a bending amount correction process for correcting the bending amount ΔR by measuring.

The second process is a work shift amount calculation process for calculating the work shift amount between the teaching position of the teaching work and the actual position of the processing work thereafter (step ST100).
Through ST300).

The third process is a process of calculating the welding start position A and the welding end position B of the processing work in which the work displacement is corrected, and moving the torch 4 to the calculated welding start position A to perform the welding. Start, and the calculated welding end position B
This is a torch position control process (step ST400) of executing the process of moving the torch 4 to perform welding.

FIG. 18 is a flow chart for explaining the wire bending operation correction processing of the prior art 3. This wire bending calculation and correction processing is to cut the tip of the wire 5 to remove the molten ball, measure the position of the fixed tool point when the wire is bent, and calculate the wire bending deviation amount ΔM. Quantity calculation processing (step ST10);
A bending amount correction process (step ST30) for correcting the bending amount by calculating the bending amount ΔR is executed.

FIG. 19 is a view showing the positions of the wire 5 and the gauge 8 during the wire bending deviation amount calculation processing of the prior art 3.
It is sectional drawing of a plane. FIG. 4A shows XZ indicating the positions of the wire 5 and the gauge 8 at the start of the wire bending deviation detection.
FIG. 4B is a cross-sectional view of the XZ plane showing the positions of the wire tip 5 a when the wire tip 5 a contacts the gauge 8.

In FIG. 19A, reference numeral 8 denotes a hollow cylindrical gauge having a bottom surface, the bottom surface of which is set at the position of the X coordinate value Xt, and 5t when the wire is not bent. It is a wire and is indicated by a dashed line. 4t is the torch position when the torch is moved to TCP0 and stopped, assuming that the wire tip touches the bottom surface of the gauge 8 (wire tip position at the start of wire bending displacement detection), and Lt is fixed. The solid line 5 is the actual bent wire, 4 is the actual torch at the same position as the torch 4t, La is the variable wire length, and ΔM is the amount of wire bending deviation.

Next, in FIG. 19B, when the torch 4 is moved until the torch 4 is brought into contact with the bottom surface of the gauge 8, the tip of the wire 5t indicated by the dashed line is shifted to the wire tip position TCP1 at the time of detecting the wire bending deviation. Move and its position TCP1
Is detected.

FIG. 20 is a flowchart for explaining the wire bending deviation amount calculation processing according to the conventional technique 3, and the processing order is as follows.

First, the detection / welding power switch 3d is switched to the detection auxiliary power device 3b (step ST11). Next, at the end of the previous welding, since a molten ball is formed at the tip of the wire 5, the wire 5 is protruded and the wire tip 5a is cut by the wire cutting device 9 (step S).
T12).

As shown in FIG. 19A, the coordinate value X of the wire tip position TCP0 at the time of starting the detection of the wire bending deviation amount.
At time t, the torch 4 is moved and stopped (step ST1).
3). In the same figure, like a torch 4t, a wire 5t
When the bend does not occur, the wire protrusion length is the fixed wire length Lt, but when the wire 5 bends downward like the torch 4, the apparent protrusion length of the wire 5 in the X direction, that is, the variable wire length La becomes It is shorter than the fixed wire length Lt by the wire bending deviation amount ΔM. At the position where the torch is stopped in step ST13, the auxiliary power supply device 3b for detection is used.
Thereby, a contact detection voltage is applied between the wire 5 and the gauge 8 (step ST14).

As shown in FIG. 19B, in order to calculate the wire bending deviation amount ΔM, the contact current detecting device 3c determines the fixed tool point when the tip of the wire 5 contacts the bottom surface of the gauge 8. The torch 4 is moved in the X direction until a coordinate value is detected (steps ST15 to ST17). The coordinate position XΔM of the fixed tool point TCP1 when the contact between the tip of the wire 5 and the bottom surface of the gauge 8 is detected (the wire tip position when the wire bending deviation is detected) is stored (step ST18).

The contact detection voltage is cut off (step ST).
19). The wire bending deviation amount ΔM and the variable wire length La are calculated by the following equations (4) and (5) (step ST20). ΔM = XΔM−Xt (4) La = Lt−ΔM (5)

Here, the coordinate value Xt of the bottom surface of the gauge 8 and the fixed wire length Lt are known, and the coordinate value XΔM of the wire bending deviation detection position TCP1 is a detected value. It is determined whether or not the calculated fluctuating wire length La is within an appropriate range. If not, the process returns to the wire cutting process (step ST12), and the wire bending deviation amount calculation process is repeated (step ST21). .

FIG. 21 is a diagram showing a Z direction coordinate value ZΔ of a bend amount detection position TCP3 for calculating a bend amount in the prior art 3.
FIG. 4 is a cross-sectional view of an XZ plane showing positions of a wire 5 and a gauge 8 when detecting R. In the figure, the wire tip position TCP2 at the start of the detection of the amount of bending is set to the position of the coordinate value Xr, and the inner peripheral surface of the gauge 8 is set to the position of the coordinate value Zt.

TCP2 is a start position for detecting the amount of bending, and TCP3 is a position where the wire 5 is connected to the gauge 8 when detecting the amount of bending.
A point at which the wire contacts the inner peripheral surface of the wire is a wire tip position at the time of wire bend amount detection (hereinafter, referred to as a wire bend amount detection position), and the wire tip is moved from a bend amount detection start position TCP2 to a bend amount detection position TCP3. . TCP4
Is a wire tip position at the time of correcting the amount of bending (hereinafter, referred to as a bending correction position), and moves the torch 4 to the Z-direction coordinate value Zc of the bending correction position.

FIG. 22 is a flowchart for explaining the bending correction processing according to the conventional technique 3, and the processing order is as follows.

After the wire bending deviation amount calculation processing, FIG.
As shown in FIG.
The wire tip 5a is moved to a bend amount detection start position (for example, X coordinate value Xr) several mm away in the direction (step ST).
31). Next, a contact detection voltage is applied between the wire 5 and the gauge 8 by the detection auxiliary power supply 3b (step ST32).

As shown in FIG. 21, in order to calculate the amount of bending ΔR, a contact point (wire bending detecting position) between the tip of the wire 5 and the inner peripheral surface of the gauge 8 is detected by the contact current detecting device 3c. The torch 4 is moved in the Z direction until (steps ST33 to ST35). Wire 5
The coordinate position ZΔR of the fixed tool point (wire bend amount detection position) TCP3 when the contact between the tip of the gauge and the inner peripheral surface of the gauge 8 is detected is stored (step ST36).

The contact detection voltage is cut off (step ST).
37). The bending amount ΔR is calculated by the following equation (6) (step ST38).

ΔR = Zt−ZΔR (6) Here, the Z-direction coordinate value Zt is a known installation position of the inner peripheral surface of the gauge 8 in the Z-direction, and the Z-direction coordinate value Zt of the bending amount detection position TCP3 The Z-direction coordinate value ZΔR is a detected value of the coordinate value of the fixed tool point when the wire tip 5a contacts the inner peripheral surface of the gauge 8.

Next, the torch 4 is moved in the Z direction from the bend amount detection position TCP3 to correct the bend amount ΔR.
A Z-direction coordinate value Zc for moving the torch 4 to the bending correction position TCP4 is calculated by the following equation (7) (step ST39).

Zc = Zt + α1 · ΔR (7) where α1 is a constant depending on the type (material, diameter, etc.) of the wire. The torch 4 is moved to the bending correction position TCP4 where the calculated coordinate value in the Z direction is Zc to correct the bending (step ST40 and step ST41).

The processing up to this point is repeated in both the positive and negative directions (vertical direction) of the Z axis, and further, in both the positive and negative directions (left and right directions) of the Y axis.

As described above, in the prior art 3, by correcting the amount of bending, the actual wire tip 5a coincides with the fixed tool point TCP, and the detection of the processing work 7 due to the variation in the protruding length of the wire 5 Variations in position (hereinafter, referred to as position detection errors) are eliminated.

[0063]

The length of the protruding wire differs at the end of each welding depending on the melting state of the wire during welding, and varies, so that the following problems are encountered in the prior art.

In the prior art 1, as described above, only the case where the variable wire length La is equal to the fixed wire length Lt is assumed, so that the fixed tool point TCP and the actual position of the wire tip 5a match. Only when this is the case, there is no position detection error, and it is possible to prevent miss swing. However, if the variable wire length La is different from the fixed wire length Lt, a position detection error occurs during touch sensing because the fixed tool point TCP does not match the actual position of the wire tip 5a. If this position detection error is large, if the wire protrusion length is short, it will miss when touch sensing,
If the wire protrusion length is long, the tip of the wire has already contacted at the start of detection, and there is a problem that the contact position of the tip of the wire cannot be detected. This will be described below.

FIG. 23 is a diagram for explaining the occurrence of a position detection error in conventional touch sensing when the variable wire length La is longer than the fixed wire length Lt. When the touch sensing is performed in the X-axis direction on the vertical surface 7a of the processing work shown in FIG. 5 described above, if the variable wire length La is longer than the fixed wire length Lt by the amount of deviation ΔL, the processing work obtained by the touch sensing is obtained. Vertical surface 7
A detection error of ΔLx is generated at the position a in the X-axis direction. When the torch 4 is inclined by an angle θ with respect to the X axis, a detection error ΔLx in the X direction of the wire deviation ΔL is calculated by the following equation (8).

ΔLx = (La−Lt) × cos θ = ΔL × cos θ (8) Therefore, although the actual wire tip 5a is at a position in contact with the vertical surface 7a, the wire tip 5a is fixed. Since it is detected as being at the position of the point TCP, the position of the tip of the wire in the X direction has a detection error of ΔLx. Similarly, the detection error when performing touch sensing in the Z-axis direction of the horizontal surface 7b of the processing workpiece and the detection error when performing touch sensing in the Y-axis direction of the thick plate surface 7c are ΔLz and ΔLy, respectively. .

FIG. 24 is a view for explaining an idle swing in the conventional work deviation amount calculation processing when the variable wire length La is shorter than the fixed wire length Lt. When the variable wire length La is shorter than the fixed wire length Lt by the shift amount ΔL, even if the fixed tool point TCP is lower than the upper end face 7d of the processing work, the wire tip 5a has the upper end face 7d of the processing work. If it is higher than this, it will be missed and the position of the workpiece for processing cannot be detected.

On the other hand, in the prior art 2, as described above, the wire 5 is pulled into the inside of the contact chip 4b, and the touch sensing is performed by the tip of the contact chip 4b. Can be prevented from scatter and swinging. However, after welding, a molten sphere is usually generated at the wire tip 5a. Therefore, in order to draw the wire 5 into the contact tip 4b, as described in the above-mentioned [0035] (1) as a disadvantage of the prior art 2, In addition, wire cutting means is required. Further, since the contact tip 4b used for detection must project beyond the nozzle 4a,
For example, when the tip of the contact tip 4b needs to be located inside the nozzle 4a as in the case of MAG welding, MIG welding, etc., (3) of the above-mentioned [0035] of the prior art 2
As shown in (1), a torch with a movable contact tip is required.

Further, also in the prior art 3, as described above with reference to FIGS. 16 to 22, wire cutting means and wire bending amount correcting means are required.

[0070]

According to the torch position control method of the first aspect, as shown in the claim correspondence diagram of FIG. 29, an arbitrary space near the work 7 or near the wire tip 5a of the torch 4 is provided. X direction, Y direction and Z with one point as the origin
An orthogonal coordinate system XYZ composed of directions is set, the torch 4 is moved to a welding start position A where the position of the work 7 for the processing is detected and the correction of the amount of work deviation is calculated, and welding is started.
Further, in the torch position control method of moving the torch to the welding end position B where the correction has been calculated and ending the welding,

(1) As shown in FIG. 26, the torch 4 is used to calculate the tip position (hereinafter referred to as a variable tool point VTCP) of the actual wire protrusion length (variable wire length) La.
To move the fixed tool point TCP to the Z coordinate value Zj of the detection start position. Next, the fixed tool point TCP is moved, and as shown in FIG. 27, the Z coordinate value Zv of the fixed tool point TCP when the wire tip 5a contacts the reference plane Zk of the reference gauge 10 is detected, and the reference plane is detected. Calculating a wire shift amount ΔL from the Z coordinate value Zk of the fixed tool point TCP and the Z coordinate value Zv of the fixed tool point TCP and storing the calculated wire shift amount ΔL;

(2) Fixed wire length Lt and wire deviation Δ
And the variable wire length La is calculated from the variable wire length L.
a variable tool point calculation process shown in the flowchart of FIG. 31 for storing the Z coordinate value of the tip position a, that is, the variable tool point Z coordinate value;

(3) By controlling the position of the variable tool point VTCP calculated in the wire shift amount calculation process and the torch angle θ with the variable tool point as a fulcrum, the actual position of the wire tip 5a and the actual wire tip are controlled. 5 to FIG. 5 to FIG. 5 to FIG. 5 to calculate the work deviation amounts ΔX, ΔY, and ΔZ between the teaching position of the teaching work 70 and the actual position of the processing work 7 to be welded thereafter while controlling the torch angle θ with the fulcrum as 8 and the work deviation amount calculation processing shown in FIGS. 10 to 12;

(4) The torch movement amount is added or subtracted by the work deviation amounts ΔX, ΔY, and ΔZ calculated in the work deviation amount calculation processing, and the welding start position A having no wire deviation amount is obtained.
A torch position control process for starting welding by moving the position of the variable tool point by moving the torch, and moving the position of the variable tool point by moving the torch to the welding end position B where there is no wire displacement; Is a torch position control method.

The torch position control device according to the second aspect is shown in FIG.
As shown in FIG. 32, an orthogonal coordinate system XYZ consisting of an X direction, a Y direction, and a Z direction with an origin at an arbitrary space near the work 7 or near the wire tip 5a of the torch 4 is set. Then, the torch 4 is moved to the welding start position A where the position of the processing work 7 is detected and the correction of the work deviation is calculated, the welding is started, and the torch 4 is moved to the welding end position B where the correction is calculated. In the torch position control device that ends welding by moving

A detection / welding power supply switch 3d for switching the output of the welding power supply 3a and the output of the detection auxiliary power supply 3b, and a reference gauge 10 arranged at a predetermined position in the rectangular coordinate system XYZ. A reference plane setting circuit ZK for presetting a reference plane signal Zks corresponding to the reference plane Zk, and a fixed wire length setting circuit LT for setting a fixed wire length signal Lts corresponding to a fixed wire length Lt which is a predetermined wire protrusion length. When,

A signal corresponding to the shape and size of the mechanical component supporting the torch 4, a signal corresponding to a predetermined position of the mechanical component, and a fixed wire length signal Lts are input, and the fixed wire length Lt is input. Fixed tool point T which is the tip position of
A fixed tool point calculation circuit TP that outputs a fixed tool point calculation signal Tps corresponding to CP, and a wire tip 5a is connected to a reference plane Z
k or the contact current detection signal I from the detection auxiliary power supply 3b when it comes into contact with the teaching work 70 or the processing work 7.
a contact current detection device 3c that outputs c.

A torch drive source MT having at least one drive source for moving the torch 4, a torch movement command circuit DT for outputting a torch movement command signal Dts for starting and stopping the movement of the torch 4,

The torch 4 is controlled by the torch movement command signal Dts.
Is moved to move the fixed tool point TCP to move the fixed tool point TCP, and the fixed tool point calculation signal Tps when the wire tip 5a comes into contact with the reference plane Zk and the contact current detection signal Ic is input is calculated. A fixed tool point reference plane storage circuit ZV for inputting and storing a fixed tool point reference plane signal Zvs corresponding to the position of the fixed tool point, a reference plane signal Zks corresponding to the Z coordinate value Zk of the reference plane, and a fixed tool point TCP
Tool point reference plane signal Zvs corresponding to Z coordinate value Zv of
And a wire shift amount signal D corresponding to the wire shift amount ΔL.
a wire shift amount calculation circuit DW that calculates and stores ws;

From the fixed tool point calculation signal Tps corresponding to the fixed tool point TCP and the wire shift amount signal Dws corresponding to the wire shift amount ΔL, a variable corresponding to the variable tool point Z coordinate value which is the tip position of the variable wire length La. Tool point signal Vps
And a variable tool point signal Vps corresponding to the torch movement command signal Dts and the variable tool point Z coordinate value.
Torch angle θ with CP position and variable tool point as fulcrum
A torch position and angle control circuit QT that outputs a torch position and angle control signal Qts for controlling

The torch 4 is controlled by the torch movement command signal Dts.
Is moved by moving the torch position angle control signal Qts when the wire tip 5a contacts the teaching position of the teaching work 70 and the contact current detection signal Ic is input. The tip end of the wire is moved by moving the torch 4 by the torch movement command signal Dts and the work teaching position storage circuit RP for storing the work teaching position signal Rps corresponding to the teaching position of the work 70, and the wire tip 5a is actually moved. The torch position angle control signal Qts when the contact current detection signal Ic is input after contacting the actual position of the work 7 to be welded is input and a work position signal Wps corresponding to the actual position of the work is stored. A work position storage circuit WP;

A work teaching position signal Rps corresponding to the teaching position of the teaching work 70 and a work position signal Wps corresponding to the actual position of the work 7 to be welded are input, and the work deviation amounts ΔX, ΔY and ΔZ are determined. Work shift amount calculation circuit WD for calculating and storing a corresponding work shift amount signal Wds
And the torch position / angle control signal Qts and the work deviation amount signal W
ds, the torch movement amount is added or subtracted by the work deviation amounts ΔX, ΔY and ΔZ, and the position of the variable tool point VTCP is moved to the welding start position A where there is no wire deviation amount by moving the torch 4. Then, the welding is started, and the position of the variable tool point VTCP is moved by the movement of the torch 4 to the welding end position B where there is no wire displacement, and the welding start / end position signal Sps for terminating the welding is output to the torch drive source MT. This is a torch position control device including a torch movement amount correction circuit SP.

[0083]

FIG. 25 is a schematic structural diagram of a torch position control device for implementing the torch position control method of the first embodiment. In the figure, the same functions as those of the automatic welding apparatus of the prior art 1 shown in FIG. 1 are denoted by the same names and the same symbols.

1 is an automatic welding device, 3 is a power supply device 3 for welding.
a, an auxiliary power supply device for detection 3b, a contact current detection device 3c, and a power switch for detecting and welding 3d, a power supply switch 4, a torch 4, a wire 5, a wire feeder 6, a wire feeder 7,
Is a work for processing. However, the reference plane Zk for detecting the coordinate value of the fixed tool point for calculating the wire shift amount ΔL of the difference between the variable wire length La and the fixed wire length Lt.
And a control device 20 shown in FIG. 32 described later.

FIG. 26 shows a coordinate value of a fixed tool point for calculating a wire shift amount ΔL of a difference between the variable wire length La and the fixed wire length Lt in a wire shift amount calculation process described later with reference to FIG. FIG. 9 is a diagram illustrating a positional relationship between a wire tip 5a and a reference plane Zk at the time of starting detection. 2, a reference Cartesian coordinate system composed of an X direction, a Y direction, and a Z direction having an origin at a point in an arbitrary space near the work 7 or near the wire tip 5a, similarly to the description of FIG. XYZ is set. The variable wire length La applied to the present invention is set in the reference rectangular coordinate system XYZ.
A reference gauge 10 having a reference plane Zk for detecting a wire shift amount ΔL of a difference between the distance and the fixed wire length Lt is arranged at a preset position. If this reference plane Zk is a plane orthogonal to the axial direction of the torch 4, X shown in FIG.
In addition to the Y plane, a YZ plane or a ZX plane may be used.

Here, the fixed wire length Lt is a predetermined value, and the position of the fixed tool point TCP is [000
7] to [0009], the position is a known position that can be calculated from the shape and size of the mechanical component supporting the torch 4 and the predetermined position of the mechanical component. Further, as will be described later, the variable wire length La is calculated from the known fixed wire length Lt and the wire shift amount ΔL detected and calculated. Therefore, the variable tool point VTCP is a position obtained by adding the wire deviation amount ΔL detected and calculated to the position of the known fixed tool point TCP, and controlling the position of the variable tool point VTCP allows the tip of the actual wire length to be adjusted. Can be controlled.

Zj is a Z coordinate value of a predetermined variable tool point detection start position (hereinafter, referred to as a variable tool point detection start Z) for calculating a variable tool point VTCP from a fixed tool point TCP described later and a wire deviation amount ΔL. The torch 4 is moved so that the Z coordinate value of the fixed tool point TCP (hereinafter, referred to as a fixed tool point Z coordinate value) comes to the variable tool point detection start Z coordinate value Zj.

FIG. 27 shows a coordinate value of a fixed tool point for calculating a wire shift amount ΔL of a difference between the variable wire length La and the fixed wire length Lt in a wire shift amount calculation process described later with reference to FIG. FIG. 6 is a diagram illustrating a positional relationship between a wire tip 5a and a reference plane Zk at the time of detection. FIG.
In 6, the torch 4 is moved in the Z direction from the position of the variable tool point detection start Z coordinate value Zj, and the torch 4 is stopped when the wire tip 5a comes into contact with the reference plane Zk. At this time, since the torch 4 moves by the moving amount ΔZm, the wire tip 5a comes into contact with the reference plane Zk as shown in FIG. 27, and the fixed tool point TCP also moves by the moving amount ΔZm of the torch 4 to the position indicated by Zv. become. The fixed tool point Z coordinate value Zv after the movement is stored.

In FIG. 26 and FIG. 27, focusing on the Z coordinate value of the fixed tool point TCP, if the torch 4 is moved from the variable tool point detection start Z coordinate value Zj by the moving amount ΔZm, the fixed tool point Z The coordinate value Zv is as follows: Zj + ΔZm = Zv (9a)

Next, paying attention to the Z coordinate value of the variable tool point VTCP, when the torch 4 moves by the movement amount ΔZm from the position obtained by adding the variable tool point detection start Z coordinate value Zj and the wire deviation amount ΔL, The point Z coordinate value coincides with the Z coordinate value Zk of the reference plane, and Zj + ΔZm + ΔL = Zk (9b).

Accordingly, from the above equations (9b)-(9a), the wire shift amount ΔL is given by ΔL = Zk−Zv (9) As described above, the wire deviation amount ΔL is calculated by storing the stored Z coordinate value Zk of the reference plane and the Z of the stored fixed tool point TCP.
From the coordinate value Zv, it is calculated by equation (9) and stored.

Next, in a variable tool point calculation process described later with reference to FIG. 29, the fluctuating wire length La is calculated from the stored fixed wire length Lt and the wire deviation amount ΔL calculated by the equation (9). The Z coordinate value of the tip position of the variable wire length La, that is, the Z coordinate value of the variable tool point is stored because it is calculated by the expression 10). La = Lt + ΔL (10)

FIG. 28 is an explanatory diagram of a work deviation amount calculation process using the variable tool point VTCP when the variable wire length La is longer than the fixed wire length Lt. FIG. 3 is an explanatory diagram when the torch 4 is moved until the wire tip 5a comes into contact with the vertical surface 7a of the work 7 for processing. In the figure, θ is the angle at which the torch 4 is inclined with respect to the XY plane (hereinafter referred to as a movement target angle), and ΔLx is the amount of wire deviation ΔL when the torch 4 is inclined with respect to the XY plane. This is a component in the X direction.

This ΔLx is the same as that of FIG.
However, in the present invention, since the wire tip 5a is controlled as the variable tool point VTCP, this ΔLx does not become an error, and the variable tool point VTCP for controlling the wire tip 5a does not become an error. Included in control. Similarly, the torch 4 is YZ plane or ZX
The component ΔLy in the Y direction of the wire deviation ΔL when inclined with respect to the plane or the component Δ in the Z direction of the wire deviation ΔL
Lz is included in the control of the variable tool point VTCP for controlling the wire tip 5a without causing an error.

FIG. 29 is a flowchart for explaining the torch position control method of the present invention. In the same drawing, the teaching procedure before the start of the processing is the same as the teaching procedure described with reference to FIG. 9, and the following four processings are performed from the start of the processing to the end of the processing.

The first process ST60 is a wire shift amount calculation process (step ST60) described later with reference to the flowchart of FIG.
61 to ST69). The fixed tool point TC is added to the variable tool point detection start Z coordinate value Zj described above with reference to FIG.
Moving P and, as previously described in FIG.
Detecting the Z coordinate value Zv of the fixed tool point TCP when the wire tip 5a comes into contact with the reference plane Zk; and detecting the Z coordinate value Zk of the reference plane and the Z coordinate value Zv of the fixed tool point TCP.
And calculating and storing the wire deviation amount ΔL from the above.

The second process ST80 is a variable tool point calculation process (step ST80) described later with reference to the flowchart of FIG.
81), is a process of calculating the variable wire length La from the fixed wire length Lt and the wire deviation amount ΔL, and storing the Z coordinate value of the tip position of the variable wire length La, that is, the variable tool point Z coordinate value.

[0098] The third processing ST100 to ST300 are as follows.
The work shift amount calculation processing (step ST1 of the first processing in FIG. 9) shown in FIGS. 5 to 8 and FIGS.
100 to ST300), and calculates the work deviation amounts ΔX, ΔY, and ΔZ between the teaching position of the teaching work 70 and the actual position of the processing work 7 to be welded thereafter.

In the third process, by controlling the position of the variable tool point VTCP calculated in the first process and the torch angle θ with the variable tool point as a fulcrum, the actual position of the wire tip 5a and its actual position are controlled. And the torch angle θ having the tip of the wire as a fulcrum. Therefore, the third process of the present invention differs from the first process of FIG. 9 in that the work deviation amounts ΔX, ΔY, and ΔZ include the correction value of the wire deviation amount ΔL.

The fourth processing ST400 is the same as that of FIG.
Is a torch position control process (steps ST401 to ST404) shown in FIG. 7, in which the torch movement amount is added or subtracted by the work deviation amounts ΔX, ΔY, and ΔZ calculated in the work deviation amount calculation process, and the welding start position A and the welding end position B and the position of the wire tip 5a is determined by the work 7 for processing.
Is moved to the welding start position A where there is no wire displacement, and the welding is started to the welding end position B where there is no wire displacement of the processing work 7.

In the fourth process of the present invention, as described in [Description of FIG. 28], the variable tool point VTCP controlling the wire tip 5a does not cause an error in the wire deviation amount as in the prior art of FIG. Included in the control of
When welding a curve or a curved surface (not shown), the teaching position at an arbitrary position on the welding line can be corrected as in the welding start position.

FIG. 30 is a flowchart for explaining the wire shift amount calculation processing of the first processing of the present invention. Less than,
The procedure of the wire shift amount calculation processing will be described with reference to FIG. First, the detection / welding power supply switch 3d is switched to the detection auxiliary power supply 3b (step ST6).
1).

By moving the torch 4, FIG.
The fixed tool point TCP is moved to the variable tool point detection start Z coordinate value Zj described in step 6 (step ST62).
A contact detection voltage is applied between the wire 5 and the reference gauge 10 by the detection auxiliary power supply 3b (Step S).
T63).

As described above with reference to FIG.
Moves the torch 4 until it contacts the reference plane Zk (step ST64), and detects that the wire tip 5a has contacted the reference plane Zk (steps ST65 and ST6).
6) After storing the Z coordinate value Zv of the fixed tool point TCP (step ST67), the contact detection voltage is cut off (step ST68).

Based on the stored Z coordinate value Zk of the reference plane and the stored fixed tool point Z coordinate value Zv, the wire deviation ΔL
Is calculated by an arithmetic expression ΔL = Zk−Zv and stored (step ST69).

FIG. 31 is a flow chart for explaining the variable tool point calculation processing of the second processing, the work shift amount calculation processing of the third processing described later, and the torch position control processing of the fourth processing of the present invention. This variable tool point calculation process (step ST81) calculates the variable wire length La from the fixed wire length Lt and the wire shift amount ΔL by the following formula: La = Lt + ΔL
And stores the Z coordinate value of the tip position of the variable wire length La, that is, the variable tool point Z coordinate value.

Next, the work deviation amount calculation processing of the third processing is as described in [0098],
Description is omitted. Further, as described in [0100], the torch position control process of the fourth process adds or subtracts the torch movement amount by the work deviation amounts ΔX, ΔY and ΔZ calculated in the work deviation amount calculation process, and The position 5a is moved to the welding start position A where there is no wire displacement amount of the processing work 7 to start welding.
Is completed at the welding end position B.

FIG. 32 is a block diagram of a control device according to claim 2 and will be described below with reference to FIG.

A control device according to a second aspect of the present invention provides an orthogonal coordinate system XYZ comprising an X direction, a Y direction, and a Z direction having an origin at an arbitrary space near the work 7 or near the wire tip 5a of the torch 4. Is set, the position of the variable tool point VTCP is moved by the movement of the torch 4 to the welding start position A where the position of the work 7 for processing is detected and the correction of the amount of deviation of the work is calculated, and welding is further started. This is a torch position control device that moves the position of the variable tool point VTCP by moving the torch 4 to the welding end position B where the correction has been calculated, and ends welding.

Reference numeral 1 denotes an automatic welding device, reference numeral 20 denotes a control device in which a circuit embodying the present invention is arranged, reference numeral 3 denotes switching between a welding power supply device 3a, a detection auxiliary power supply device 3b, a contact current detection device 3c, and a detection / welding power supply. A power supply device including the switch 3d, 4 is a torch, 5 is a wire, 6 is a wire feeder, and 7 is a work for processing.

The contact current detecting device 3c has a wire tip 5a
Outputs a contact current detection signal Ic from the detection auxiliary power supply device 3b when it comes into contact with the reference surface Zk of the reference gauge 10 described later, the teaching work 70 or the processing work 7.

The detection / welding power switch 3d is
The output of the welding power supply 3a and the output of the detection auxiliary power supply 3b are switched.

The reference gauge 10 has a reference surface (for example, Zk) for detecting contact at the position of the wire tip position 5a (for example, Z coordinate value) for calculating a variable tool point VTCP described later. I have.

The reference plane setting circuit ZK has a rectangular coordinate system XYZ.
The reference plane signal Zks corresponding to the reference plane Zk of the reference gauge 10 arranged at a predetermined position is set in advance and stored.

The fixed wire length setting circuit LT sets a fixed wire length signal Lts corresponding to a fixed wire length Lt which is a predetermined wire protrusion length.

The fixed tool point calculation circuit TP converts a signal corresponding to the shape and size of the mechanical component supporting the torch 4, a signal corresponding to a predetermined position of the mechanical component, and a fixed wire length signal Lts. It outputs a fixed tool point calculation signal Tps corresponding to the fixed tool point TCP which is the tip position of the fixed wire length Lt.

The torch drive source MT has one or more drive sources for moving the torch 4. The torch movement command circuit DT outputs a torch movement command signal Dts for commanding start and stop of the movement of the torch 4.

The fixed tool point reference plane storage circuit ZV moves the torch 4 by the torch movement command signal Dts to move the fixed tool point TCP, and the wire tip 5a comes into contact with the reference plane Zk and the contact current detection signal Ic Is input, and the fixed tool point reference plane signal Zvs corresponding to the position of the fixed tool point is stored.

The wire shift amount calculation circuit DW calculates the Z of the reference plane.
The reference plane signal Zks corresponding to the coordinate value Zk and the fixed tool point T
A wire shift amount signal Dws corresponding to the wire shift amount ΔL is calculated from the fixed tool point reference plane signal Zvs corresponding to the Z coordinate value Zv of the CP and stored. The wire shift amount ΔL is calculated by the calculation formula ΔL = Zk−Zv.

The variable tool point calculation circuit VP calculates a variable tool which is the tip position of the variable wire length La from the fixed tool point calculation signal Tps corresponding to the fixed tool point TCP and the wire shift amount signal Dws corresponding to the wire shift amount ΔL. A variable tool point signal Vps corresponding to the point Z coordinate value is calculated and stored. The fluctuating wire length La is calculated by a calculation formula La = Lt + ΔL.

The torch position / angle control circuit QT receives the torch movement command signal Dts and the variable tool point signal Vps corresponding to the variable tool point Z coordinate value, and inputs the variable tool point VTCP.
And a torch position angle control signal Qts for controlling the torch angle θ with the position of and the variable tool point as a fulcrum.

The work teaching position storage circuit RP moves the torch 4 in response to the torch movement command signal Dts, and the torch when the wire tip 5a contacts the teaching position of the teaching work 70 and the contact current detection signal Ic is input. The position and angle control signal Qts is input, and a work teaching position signal Rps corresponding to the teaching position of the teaching work 70 is stored.

The work position storage circuit WP moves the torch 4 in response to the torch movement command signal Dts,
a is in contact with the actual position of the work 7 to be actually welded, and the torch position angle control signal Qts when the contact current detection signal Ic is input to input the work position corresponding to the actual position of the work 7 The signal Wps is stored.

The work shift amount calculation circuit WD inputs a work teaching position signal Rps corresponding to the teaching position of the teaching work 70 and a work position signal Wps corresponding to the actual position of the work 7 to be welded. Work shift amount signals Wds corresponding to the shift amounts ΔX, ΔY, and ΔZ are calculated and stored.

The torch movement amount correction circuit SP receives the torch position angle control signal Qts and the work deviation amount signal Wds, and adds or subtracts the torch movement amount by the work deviation amounts ΔX, ΔY and ΔZ. The position of the variable tool point VTCP is moved by moving the torch 4 to the welding start position A with no amount to start welding, and the variable tool point V is moved by moving the torch 4 to the welding end position B with no wire displacement.
A welding start / end position signal Sps for terminating the welding by moving the position of the TCP is output to the torch drive source MT.

In this torch movement amount correction circuit SP,
Variable tool point VT calculated by variable tool point calculation circuit VP
Torch angle θ with CP position and variable tool point as fulcrum
Is controlled, and the position of the actual wire tip 5a and the torch angle θ with the actual wire tip as a fulcrum are controlled.

In the embodiment, the coordinate value Zk in the Z direction is used as the coordinate value of the reference plane, but the coordinate value Xk in the X direction is used.
Alternatively, the coordinate value Yk in the Y direction may be used. Also, the coordinate value Zj in the Z direction is used as the coordinate value of the variable tool point detection start, but the coordinate value Xj in the X direction or the coordinate value Yj in the Y direction
May be used. Further, the control device of the present invention can use an independent dedicated circuit, a composite circuit sharing a part thereof, a computer circuit controlled by a program having the same function as the dedicated circuit, and the like.

[0128]

According to the torch position control method of the first aspect and the torch position control apparatus of the second aspect, even when the actual wire protrusion length when detecting the position of the work to be processed is not the predetermined length, Since the position of the wire tip is controlled by using the actual wire tip as a variable tool point, there is no means to correct the wire length, and there is no swing when detecting the position of the workpiece, and the work piece due to variation in the wire protrusion length Variations in the detection position 7 can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an automatic welding apparatus according to Prior Art 1.

FIG. 2 is a layout view of a work for processing.

FIG. 3 is a cross-sectional view of the tip of the torch at a predetermined wire protrusion length (fixed wire length).

FIG. 4 is a cross-sectional view of the tip of the torch when the wire protrusion length (variable wire length) actually changes.

FIG. 5 is a diagram illustrating a teaching position and a detection position when the torch 4 is moved in the X direction and the Z direction during the work shift amount calculation processing.

FIG. 6 is a diagram illustrating a teaching position and a detection position when the torch 4 is moved in the Z direction and the Y direction during the work shift amount calculation processing.

FIG. 7 is an explanatory diagram of a first prior art work shift amount calculation process that is detected by bringing a wire tip into contact with a work for processing.

FIG. 8 is a diagram showing a taught welding start position and a welding end position, and a welding start position and a welding end position at the time of welding;

FIG. 9 is a flowchart illustrating the operation of the automatic welding apparatus of FIG.

FIG. 10 is a flowchart illustrating an operation order of an X-direction work deviation amount calculation process.

FIG. 11 is a flowchart illustrating an operation sequence of a Z-direction work deviation amount calculation process.

FIG. 12 is a flowchart illustrating an operation sequence of a Y-direction work deviation amount calculation process.

FIG. 13 is a flowchart illustrating an operation sequence of a torch position control process.

FIG. 14 is a flowchart illustrating the operation of the automatic welding apparatus according to the conventional technique 2.

FIG. 15 is an explanatory diagram of a second prior art work shift amount calculation process for detecting the tip of a contact tip by contacting the work to be processed;

FIG. 16 is a diagram showing a configuration of an automatic welding apparatus according to Prior Art 3;

FIG. 17 is a flowchart illustrating the operation of the automatic welding apparatus according to the conventional technique 3.

FIG. 18 is a flowchart illustrating a wire bending calculation and correction process according to Conventional Technique 3.

FIG. 19 is a cross-sectional view of the XZ plane showing the positions of wires and gauges during wire bending deviation amount calculation processing according to Prior Art 3;

FIG. 20 is a flowchart illustrating a wire bending deviation amount calculation process according to the related art 3.

FIG. 21 is a cross-sectional view in the XZ plane showing positions of a wire and a gauge when detecting a coordinate value ZΔR in a Z direction of a bending amount detection position TCP3 for calculating a bending amount according to Prior Art 3;

FIG. 22 is a flowchart illustrating a bend amount correction process according to a third related art;

FIG. 23 is a diagram illustrating the occurrence of a position detection error in conventional touch sensing when the variable wire length La is longer than the fixed wire length Lt.

FIG. 24 is a diagram for explaining a miss swing in the work shift amount calculation processing of the related art when the variable wire length La is shorter than the fixed wire length Lt.

FIG. 25 is a schematic configuration diagram of a torch position control device that implements the torch position control method of the first embodiment.

FIG. 26 is a diagram illustrating the wire tip 5a at the time when the detection of the coordinate value of the fixed tool point for calculating the wire shift ΔL of the difference between the variable wire length La and the fixed wire length Lt in the wire shift amount calculation processing; FIG. 7 is a diagram showing a positional relationship with a reference plane Zk.

FIG. 27 shows the wire tip 5a and the reference plane at the time when the coordinate value of the fixed tool point for calculating the wire shift ΔL of the difference between the variable wire length La and the fixed wire length Lt is detected in the wire shift amount calculation processing. It is a figure showing the positional relationship with Zk.

FIG. 28 is an explanatory diagram of a work shift amount calculation process using the variable tool point VTCP when the variable wire length La is longer than the fixed wire length Lt.

FIG. 29 is a flowchart illustrating a torch position control method of the present invention.

FIG. 30 is a flowchart illustrating a wire shift amount calculation process of the first process of the present invention.

FIG. 31 is a flowchart illustrating a variable tool point calculation process of the second process, a work deviation amount calculation process of the third process, and a torch position control process of the fourth process according to the present invention.

FIG. 32 is a block diagram of a control device according to claim 2;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 automatic welding device 2 control device 20 control device 3 power supply device 3a welding power supply device 3b detection auxiliary power supply device 3c contact current detection device 3d detection / welding power supply switch 4 welding torch (torch) 4a shield gas nozzle (nozzle) 4b Contact tip 5 Consumable electrode (wire) 5a Wire tip 6 Wire feeding device 6a Wire reel 6b Wire feeding roller 6c Motor for feeding roller drive 7 Workpiece to be welded (working work) 7a Vertical surface of work for processing 7b For processing Horizontal plane of the work 7c Thick surface of the work for processing 7d Upper end surface of the work for processing 70 Work during teaching (teaching work) 7a0 Vertical surface during teaching 7b0 Horizontal surface during teaching 7c0 Plate thick surface during teaching 8 Wire straightening Gauge (gauge) 9 Wire cutting device 10 Reference gauge ΔX Work position in X-axis direction Deviation ΔY Work position deviation in the Y-axis direction ΔZ Work position deviation in the Z-axis direction A Welding start position A0 Welding start position B Welding end position B0 Welding end teaching position Wy Welding line Wy0 Teaching welding line TCP Fixed tool point VTCP Variable tool point Lt Predetermined wire protrusion length (fixed wire length) La Actual wire protrusion length (variable wire length) TCP0 Wire tip position at the start of wire bending deviation detection TCP1 Wire leading position at wire bending deviation detection TCP2 Wire tip position at the time of detecting wire bending amount TCP3 Wire tip position at the time of detecting wire bending amount TCP4 Wire tip position at the time of correcting wire bending amount ΔM Wire bending displacement ΔL Wire tip X direction displacement (wire displacement) ΔR Displacement (bend) in the wire tip Z direction ΔLx X direction detection Error XΔM Coordinate value of TCP1 in X direction ZΔR Coordinate value of TCP3 in Z direction Xt coordinate value of gauge 8 Zt coordinate value of gauge 8 Xr coordinate value of TCP2 X direction Zj Variable tool point detection start Z coordinate value Zk Z-direction coordinate value of upper end face of reference gauge 10 (reference plane) ΔZm Movement amount of torch from the start of variable tool point detection Z coordinate Zj to contact with reference plane Zk at the end of wire Zv Fixed tool point Z coordinate value after movement θ Angle formed by the torch 4 with respect to the plane of the orthogonal coordinate system (torch angle) MT Torch drive source ZK Reference plane setting circuit LT Fixed wire length setting circuit TP Fixed tool point calculation circuit DT Torch movement command circuit ZV Fixed tool point reference plane storage circuit DW Wire shift amount calculation circuit VP Variable tool point calculation circuit QT Torch position angle control circuit RP Work teaching position storage circuit WP Work position storage circuit WD Work shift amount calculation circuit SP Torch movement amount correction circuit Zks Reference plane signal Lts Fixed wire length signal Tps Fixed tool point calculation signal Dts Torch movement command signal Zvs Fixed tool point reference plane signal Dws Wire shift amount signal Vps Variable tool point signal Dts Torch movement command signal Qts Torch position angle control signal Rps Work teaching position signal Wps Work position signal Wds Work shift amount signal Sps Weld start / end position signal

──────────────────────────────────────────────────続 き Continued on the front page (72) Koji Kurahashi 2-11-11 Tagawa, Yodogawa-ku, Osaka-shi Daihen Co., Ltd. (56) References JP-A-55-14150 (JP, A) JP-A-61- 95779 (JP, A) JP-A-60-261676 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 9/127 G05B 19/404

Claims (2)

(57) [Claims] 1. An X-direction and a Y-direction each having an origin at an arbitrary point in an arbitrary space near a processing work or near a wire tip of a torch.
By setting a rectangular coordinate system XYZ consisting of a direction and a Z direction,
In the torch position control method, the torch is moved to the welding start position where the position of the work for processing is detected and the correction of the work deviation amount is calculated, the welding is started, and the torch is moved to the welding end position to finish the welding. By moving the torch, the fixed tool point, which is the tip position of the wire with the predetermined wire protrusion length as the fixed wire length, is moved, and the wire tip is moved to the reference surface of the reference gauge disposed at the predetermined position. Detecting a coordinate value of the fixed tool point at the time of contact, calculating a wire shift amount from the coordinate value of the reference plane and the coordinate value of the fixed tool point and storing the wire shift amount; A variable tool point calculation process of calculating a variable wire length from the wire length and the wire shift amount and storing a variable tool point coordinate value that is a coordinate value of a tip position of the variable wire length; By controlling the position of the variable tool point and the torch angle with the variable tool point as a fulcrum, the position of the actual wire tip and the torch angle with the actual wire tip as a fulcrum are controlled. Work displacement calculation processing for calculating the work displacement between the teaching position and the actual position of the work to be welded thereafter, and welding with no wire displacement by adding or subtracting the torch movement by the work displacement. The torch position where the position of the variable tool point is moved to the start position by moving the torch to start welding, and the position of the variable tool point is moved by the movement of the torch to the welding end position where there is no wire displacement to end welding. A torch position control method including a control process. 2. The X direction and the Y direction each having an origin at an arbitrary space near the workpiece for processing or near the tip of the wire of the torch.
By setting a rectangular coordinate system XYZ consisting of a direction and a Z direction,
In the torch position control device that detects the position of the work for processing, moves the torch to the welding start position where the calculation of the work deviation amount was calculated, starts welding, moves the torch to the welding end position, and ends welding A detection / welding power switch for switching between the output of the welding power supply and the output of the detection auxiliary power supply, and a reference surface corresponding to a reference surface of a reference gauge disposed at a predetermined position in the rectangular coordinate system. A reference plane setting circuit for presetting a signal, a fixed wire length setting circuit for setting a fixed wire length signal corresponding to a fixed wire length that is a predetermined wire protrusion length, and the shape and mechanical components supporting the torch A signal corresponding to the dimension, a signal corresponding to a predetermined position of the mechanical component, and a fixed wire length signal are inputted, and a reference is made to a fixed tool point which is a tip position of the fixed wire length. A fixed tool point calculation circuit for outputting a fixed tool point calculation signal to be output, and a contact current detection signal output from the auxiliary power supply device for detection when the tip of a wire comes into contact with the reference surface or the work for teaching or the work for processing. Current detection device, a torch drive source having one or more drive sources for moving the torch, a torch movement command circuit for outputting a torch movement command signal for instructing start and stop of the movement of the torch, and the torch movement The fixed tool point calculation signal when the wire tip is moved by moving the torch by a command signal to move the fixed tool point, and the wire tip contacts the reference surface and the contact current detection signal is input. A fixed tool point reference plane storage circuit for storing a fixed tool point reference plane signal corresponding to the position of the fixed tool point; A wire shift amount calculation circuit that calculates and stores a wire shift amount signal corresponding to a wire shift amount from a surface signal and the fixed tool point reference surface signal; and calculates the wire shift amount signal from the fixed tool point calculation signal and the wire shift amount signal. A variable tool point calculation circuit for calculating and storing a variable tool point signal corresponding to a variable tool point Z coordinate value which is a tip position of a variable wire length; and inputting the torch movement command signal and the variable tool point signal. A torch position and angle control circuit that outputs a torch position and angle control signal for controlling the position of the variable tool point and the torch angle with the variable tool point as a fulcrum; The torch position angle when the wire tip is moved to contact the teaching position of the teaching work and the contact current detection signal is input. A work teaching position storage circuit for inputting a control signal and storing a work teaching position signal corresponding to the teaching position of the teaching work, and moving the tip of the wire by moving the torch by the torch movement command signal, The torch position angle control signal when the tip contacts the actual position of the work to be actually welded and the contact current detection signal is input to input a work position signal corresponding to the actual position of the work to be processed. A work position storage circuit for storing;
A work shift amount calculation circuit for inputting the work teaching position signal and the work position signal for processing and calculating and storing a work shift amount signal corresponding to the work shift amount; a torch position angle control signal and a work shift amount Input the signal and add or subtract the torch movement amount by the work deviation amount, move the position of the variable tool point by moving the torch to the welding start position where there is no wire deviation amount, and start welding. A torch position control device comprising: a torch moving amount correction circuit for moving the position of the variable tool point by moving the torch to a welding end position having no displacement and outputting a welding start / end position signal for terminating welding to a torch drive source. .