JPS6322913B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding line in an automatic welding device that controls the position of a workpiece and a position sensor along at least two intersecting translational axes, when a groove angle is not given in advance. The present invention relates to a position detection method.

As a method for detecting the position of the weld line as described above,
Conventionally, for example, JP-A-15441 and JP-A-54-
It is known from the publication No. 119353. In these conventional methods, a position sensor is first positioned in advance on one of the groove surfaces of the workpiece, and (a) after detecting one point on the one groove surface, Detecting two points and another point on one of the groove surfaces, resulting in a total of four points, calculating the position of the intersection line of both groove surfaces, that is, the position of the weld line, and as a result of the calculation, The obtained position is the weld line position.

(b) The surface of the workpiece and the groove surface are sequentially detected at regular intervals in the direction of the bottom of the groove surface, and the direction of the slope of the groove surface is determined. If the direction of the slope is opposite, the above-mentioned The position of the groove surface that has slightly returned in the opposite direction to the direction in which it was displaced is detected at regular intervals, and the detected position is taken as the position of the weld line.

By the way, when detecting the weld line on the workpiece,
Particularly when there is a problem with the positioning accuracy of the workpiece, it may be difficult to ensure that the position sensor is located above the groove surface of the workpiece at the beginning of sensing. In such cases, it is difficult to detect the position of the weld line using conventional methods.

This invention was made in view of the above-mentioned circumstances, and it is possible to reliably detect the position of the weld line even when there is a problem with the positioning accuracy of the workpiece, such that it is difficult to place the position sensor above the groove surface at the beginning of sensing. The aim is to provide a method that can be used.

Examples will be described in detail below.

First, the embodiments shown in FIGS. 1 to 4b will be described in detail. Although the automatic welding apparatus of this embodiment will be described as being designed to determine the relative position between the workpiece and the position sensor using orthogonal coordinates, for example, the relative position may be determined using polar coordinates or cylindrical coordinates.
In addition, the position information in polar coordinates or cylindrical coordinates may be converted into at least two intersecting translational axes (for example, rectangular coordinates) to control the position.
This invention is not limited to this embodiment.

In FIG. 1, this automatic welding device 100 includes:
Attach the fixture 105 of the workpiece W (not shown) to the left and right,
The torch 109 is configured so that it can be moved in the front-back direction or rotated around the horizontal axis H, and the fixture 108 of the torch 109 is configured to be moved in the up-down direction or rotated around the vertical axis L. A control box 400 including a computer for automatically controlling the position is provided. Let me explain in more detail.

A first frame 102 is fixed to one side of the L-shaped floor plate 101 in plan view. A cart 103 that is movable in the left-right direction (X-axis direction in the figure) is provided on the top of the frame 102. The power means (not shown) for this truck 103 is a known motor with a brake equipped with a speed reducer in this embodiment, and the power transmission means (not shown) is a known engagement means (so-called ball screw). In addition, a second frame 1 that is movable in the front-rear direction (Y-axis direction in the figure) is mounted on the upper part of the trolley 103.
04 is provided. Although not shown, the power means and power transmission means of this frame 104 are also a similar motor with a brake and a ball screw with a speed reducer.

A workpiece holder 105 is provided at the front of the frame 104 and is rotatable in the Θ axis direction in the figure. Although not shown, the power means of this workpiece fixture 105 is also a known motor with a brake and a reduction gear.

A third frame 1 is attached to the other side end of the floorboard 101.
06 will be erected. This frame body 106 has an arm 107 that is movable in the vertical direction (Z-axis direction in the figure).
will be provided. Although not shown, the power means and power transmission means of this arm 107 are also a similar motor with a brake and a ball screw with a speed reducer. A fixture 108 for a torch 109 is provided at the tip of the arm 107 and is rotatable around the vertical axis L (in the direction of the Θ axis in the figure). The power means for this torch mount 108 is also not shown, but
This is a known motor with a brake and a reduction gear. Furthermore, the mounting position of the torch 109 is
The welding point WP on the center line extension of 9 is the vertical axis L.
Furthermore, the mounting angle is optimally selected depending on the welding mode to be performed (butt welding, fillet welding, etc.) and the shape of the workpiece W.

Further, a current is applied to the torch 109 from a power supply device 200. The control box 400 and the welding control device 300 automatically control the forward rotation, reverse rotation, moving speed, welding current, etc. of the power means (motor with a brake with a speed reducer) of each part according to the program, and the welding Point WP is workpiece W (not shown)
The mutual positions of the two fixtures 105 and 108 are controlled so that automatic welding can be performed along the welding line and in the position with the best welding conditions. Remote control ("remote control") for the purpose of creating a program for that purpose or for the purpose of manual operation.
A panel 500 is provided.

In this embodiment, the welding point WP on the extension of the center line of the torch 109 is configured to coincide with the vertical axis L, so it remains constant regardless of the rotation of the fixture 108 in the Θ axis direction. The attitude of the torch 109 with respect to the same welding point can be changed arbitrarily by rotating the fixture 108 (in the Θ axis direction). That is, this embodiment is an automatic welding device with five degrees of freedom.

Next, a part of an embodiment of the present invention will be described in detail with reference to FIG.

Work W is a groove weld line of a square joint as shown in the figure.
It shall have WL. A consumable electrode supply means 201 for the tote 109 is provided in the power supply device 200 . The supply means 201 further includes a consumable electrode forcer 202 . In this embodiment, the force device 20
2 is formed by forming a consumable electrode guide flexible tube into a loop shape. Of course, the forcing device 202 may also be of a type that straightens the consumable electrode with a guide roller. Reference numeral 203 denotes a known potential applying means for the consumable electrode, and a changeover switch 204
A welding power source 205 and a high-voltage discharge power source 206 (voltage approximately 100 to 2000 V,
The current is designed so that only a small amount of current can flow through it. ) and are designed to be selectively connected. Further, the power source 205 is directly connected to the workpiece W, and the power source 206 is connected to the workpiece W via a current sensor 207. An output signal associated with a change in current value at sensor 207 is connected to be input to control box 400 . Further, the switch 204 is normally connected to a power source 205 as shown in the figure, and is configured to be switched to a power source 206 by a command from the control box 400.

An embodiment of the method of the present invention will now be described for detecting the position of a welding line WL on a workpiece W as shown in FIGS. 2 and 3. Please also refer to the flowchart shown in FIG. 4 below. Note that this workpiece W has its surface
It is assumed that the inclination angles of F ₁ and F ₂ are not given in advance.

(1) First, as shown in Figures 2 and 3, welding line of work W
WL is controlled to be approximately perpendicular to the X-axis and Z-axis (that is, approximately parallel to the Y-axis), and the groove surface of the workpiece W is controlled to be open with respect to the Z-axis.

(2) Then commands the switch 204 to be switched to the power source 206 side.

(3) Control the welding point of the torch 109 by commanding the position to point Pa. Point Pa is above the workpiece W,
and is predetermined at a location above one surface _F1 .

(4) Commanding the torch 109 to move in the (-) direction of the Z-axis, checking whether the tip electrode of the torch 109 approaches the surface F ₁ and outputting a signal;
If there is an output, then a command is given to stop the movement of the torch 109, and the position information of the detected position Pb at that time is stored in the computer.

(5) Command the workpiece W to move by △Xa in the (-) direction of the X-axis, and when the movement is completed,
The torch 109 is commanded to move in the (-) direction of the Z axis, and the tip electrode of the torch 109 is
Check whether it outputs a signal by approaching F ₁ ,
If there is an output, then a command is given to stop the movement of the torch 109, and the position information of the detected position Pc at that time is stored in the computer.

(6) Command to move the torch 109 in the (+) direction of the Z-axis to the height of the Pa position, and when the movement is completed, command to move the work W in the (+) direction of the X-axis by △Xb. do. This △Xb
The value of is set in advance so that the welding point of the torch 109 is positioned sufficiently above the surface _F2 due to the movement.

(7) When the movement in step (6) is completed, the torch 109 is commanded to move in the (-) direction of the Z axis, and the tip electrode of the torch 109 approaches the surface F ₂ and outputs a signal. If there is an output, a command is given to stop the movement of the torch 109 at that time, and the detected position Pd at that time is
location information is stored in the computer.

(8) Command the workpiece W to move by △Xa in the (+) direction of the X-axis, and when the movement is completed,
A command is given to move the torch 109 in the (-) direction of the Z-axis. Then, it is checked whether the tip electrode of the torch 109 approaches the surface F ₂ and outputs a signal, and if there is an output, then the torch 109
A command is given to stop the movement of Pe, and the position information of the detected position Pe at that time is stored in the computer.

(9) Based on the position information of Pb, Pc, Pd, and Pe,
The position P ₀ of the intersection line of F ₁ and F ₂ is calculated, and a command is given to position the welding point of the torch 109 at the P ₀ position. As a result, the relative position between the workpiece W and the position sensor (namely, the torch 109) is such that the torch 109 is positioned at a position P ₀ appropriately remote from the groove surface of the workpiece W in the Z-axis direction.

(10) Command the torch 109 to move in the (-) direction of the Z-axis, check whether the tip electrode of the torch 109 approaches the groove surface and outputs a signal;
If there is an output, then a command is given to stop the movement of the torch 109. Note that the groove surface detection position at this time is _P1 .

(11) Command to move the torch 109 by _ΔZ1 in the (+) direction of the Z-axis, and when the movement is completed, command to move the workpiece W in the (-) direction of the X-axis. Then, it is checked whether the tip electrode of the torch 109 approaches one of the groove surfaces and outputs a signal, and if there is an output, then the work W
A command is given to stop the movement of P2, and the position information of the detected position _P2 at that time is stored in the computer.

(12) Command the work W to move in the (+) direction of the X-axis, check whether the tip electrode of the torch 109 approaches the other groove surface and output a signal, and if there is an output, , then issues a command to stop the movement of the workpiece W, and stores the positional information of the detected position _P3 at that time in the computer.

(13) Command to move the torch 109 in the (+) direction of the Z-axis by ΔZ ₁ , and when the movement is completed, command to move the workpiece W in the (+) direction of the X-axis. Then, it is checked whether the tip electrode of the torch 109 approaches the other groove surface and outputs a signal, and if there is an output, then the work W
A command is given to stop the movement of P4, and the position information of the detected position _P4 at that time is stored in the computer.

(14) Command the work W to move in the (-) direction of the X-axis, check whether the tip electrode of the torch 109 approaches one of the groove surfaces and outputs a signal, and if there is an output, , then issues a command to stop the movement of the work W, and stores the position information of the detected position _P5 at that time in the computer.

(15) Using the position information of P ₂ , P ₃ , P ₄ , and P ₅ , calculate the position Pf ₁ of the intersection line of both groove surfaces, that is, the position of the weld line WL.

With steps (1) to (15) above, the welding line WL position detection step is completed, and the torch 1 is set to P _f1 as the welding point command position.
However, in this embodiment, the actual welding point command position is set to torch 1 in consideration of the material, plate thickness, welding mode, etc. of the workpiece W.
A position where the welding point 09 is slightly displaced from the P _f1 position in the (+) direction of the Z axis is set as the welding point command position.

Next, the embodiment shown in FIGS. 5 and 6 will be explained.

In this embodiment, the welding point of the torch 109 is
The steps up to positioning at the _P0 position are the same as steps (1) to (9) in the previous embodiment, so their explanation will be omitted and the subsequent steps will be explained.

(21) Command the torch 109 to move in the (-) direction of the Z-axis, and the tip electrode of the torch 109
It is checked whether a signal is output when approaching the groove surface, and if there is an output, a command is given to stop the movement of the torch 109 at that time, and the position information of the detected position _P1 at that time is stored in the computer. do.

(22) Command to move the torch 109 in the (+) direction of the Z axis by △Z ₂ , and when that movement is completed, command to move the workpiece W in the (+) direction of the X axis by △X . When the movement is completed, the torch 109 is commanded to move in the (-) direction of the Z-axis, and it is checked whether the tip electrode of the torch 109 approaches the groove surface and outputs a signal. If there is, then a command is given to stop the movement of the torch 109, and the position information of the detected position _P2 at that time is stored in the computer.

(23) Calculate the slope of the line segment connecting P ₁ and P ₂ using the position information of P ₁ and P ₂ .

(24) If the slope of the line segment connecting P ₁ and P ₂ is in the (+) direction, the same action as in step (22) is performed, and the groove surface position Pn (n; 3, 4 ,5...
), and each time it is detected, the position information is stored in the computer, and the slope of the line segment connecting Pn _-1 and Pn is calculated in the same way as in step (23).

(25) And the slope of the line connecting Pn _-1 and Pn is (+)
If the direction changes from the direction of (-) to the direction of (-),
The position information of Pn _-1 is stored in the computer as the position of the intersection line of both groove surfaces, that is, the position P _f2 of the welding line WL.

(26) If the calculation result of step (23) is P ₁ , P ₂
If the inclination of the line segment connecting is in the (-) direction, command is given to move the torch 109 by △Z ₂ in the (+) direction of the Z-axis, and when the movement is completed, the workpiece W is moved in the (-) direction of the X-axis. -) direction to move the torch 109 by △ 109 tip electrodes,
It is successively checked whether a signal is output when approaching the groove surface, and if there is an output, a command is given to stop the movement of the torch 109 at that time, and the detection position Pn (n; 3, 4 , 5...) is stored in the computer, and Pn _-1 ,
The slope of the line segment connecting Pn is also calculated.

(27) And the slope of the line connecting Pn _-2 and Pn is (-)
If the direction changes from the direction of (+) to the direction of (+),
The position information of Pn _-1 is stored in the computer as the position of the intersection line of both groove surfaces, that is, the position P _f2 of the welding line WL.

In this way, the position of P _f2 is determined and a position command is given to the torch 109 using P _f2 as the welding point command position. However, the actual welding point command position is from P _f2 to Z
The position is slightly displaced in the (+) direction of the axis. Note that P _f2 in this case does not necessarily match the position of the intersection line of both groove surfaces, that is, the position of the weld line WL, but
There are no problems in implementation.

In the above description, the position of the weld line on the groove surface of a square joint is detected, but it is obvious that the groove surfaces of various types of joints (excluding I-shaped grooves) can be similarly detected. Further, the position sensor may not be used also as the torch 109, but may be provided separately at a position having a certain relationship with the torch 109, and may be either a contact type or a non-contact type. It goes without saying that the technical scope of the present invention also includes the replacement of each component with equivalents.

As described above, this invention first detects two points Pb, Pc, Pd, and Pe on both surfaces F ₁ and F ₂ of the workpiece W, and then uses this positional information to determine the intersection line of both surfaces F ₁ and F ₂ . After calculating the position P ₀ and once positioning the position sensor at this P ₀ position, the groove surface of the workpiece W is detected to fully detect the position of the weld line. When detecting the position of the weld line by detecting the tip surface, the position sensor can be reliably positioned above the groove surface, that is, at the P ₀ position, at the beginning of full-scale sensing.
Therefore, even if there is a problem with the positioning accuracy of the work W, the position of the weld line can be detected accurately and reliably.

[Brief explanation of the drawing]

Figures 1 to 4b show an embodiment of the present invention, Figure 1 is an overall perspective view of an automatic welding device, Figure 2 is an explanatory diagram of main parts, Figure 3 is an explanatory diagram of the operation, and Figures 4a and 4b are It is a flowchart. 5 and 6 show another embodiment of the present invention, FIG. 5 is an explanatory diagram of the operation, and FIG. 6 is a flowchart. In the figure, 100... automatic welding device, 105...
Fixture for work W, 109...Torch (also serves as position sensor), W...Work, WL...Welding line, P _f1 , P _f2
...Position of the intersection line of both groove surfaces (position of weld line WL),
206...High voltage power supply for discharge (power supply for detection), 207
...Current sensor, 400...Control box.

Claims (1)

[Claims] 1. In an automatic welding device designed to control the position of a workpiece and a position sensor along at least two intersecting translational axes (for example, the X-axis and the Z-axis), the groove angle is not given in advance. In the welding line position detection method of Further, the position sensor is provided in the Z-axis direction, the output of the position sensor is input to a computer, and the position of the weld line is detected by a program including the following steps. (A) A step of determining the relative position of the workpiece and the position sensor to a position Pa appropriately remote from one surface _F1 of the workpiece in the Z-axis direction. (B) A step of moving the relative position of the workpiece and the position sensor closer in the Z-axis direction from the Pa position, detecting the one surface _F1 , and storing information on the position Pb. (C) After the relative positions of the workpiece and the position sensor are displaced ΔXa from the Pb position in the X-axis direction, they are brought closer together in the Z-axis direction, and the one surface
Step of detecting _F1 and storing information of its position Pc. (D) After moving the relative position of the workpiece and the position sensor away from the Pc position in the Z-axis direction,
Displace △Xb in the X-axis direction, and further displace the Z
A step of detecting the other surface _F2 by approaching it in the axial direction and storing information on its position Pd. (E) After the relative positions of the workpiece and the position sensor are displaced ΔXa from the Pd position in the X-axis direction, the workpiece and the position sensor are moved closer together in the Z-axis direction, and the position sensor is moved toward the other surface.
Step to detect F ₂ and store information of its position Pe. (F) From the information of each position Pb, Pc, Pd, Pe,
Step to calculate the position Po of the intersection line of F ₁ and F ₂ . (G) The relative position of the workpiece and the position sensor is
Step to position to Po position. (H) A step of moving the relative position of the workpiece and the position sensor closer in the Z-axis direction from the Po position, detecting the groove surface, and storing information on the position _P1 . (I) A step of moving the relative position of the workpiece and the position sensor away from the _P1 position by _ΔZ1 in the Z-axis direction. (J) Displace the relative position of the workpiece and the position sensor from the position of step (I) in the X-axis direction, detect one point on each of both groove surfaces of the workpiece, and determine the positions P ₂ , P Step ₃ to store information. (K) Adjust the relative position of the workpiece and the position sensor in the Z-axis direction from the detection position of the step (J).
Step to remote only Z ₁ . (L) Displace the relative position of the workpiece and the position sensor from the position of the step (K) in the X-axis direction, detect one point on each of both groove surfaces of the workpiece, and determine the positions P ₄ , P ₅ steps to store information. (M) Based on the information on each of the positions P ₂ , P ₃ , P ₄ , and P ₅ ,
A step of calculating the position P _f1 of the weld line. 2. The position of the welding line when the groove angle is not given in advance in an automatic welding device designed to control the position of the workpiece and the position sensor along at least two intersecting translational axes (for example, the X-axis and the Z-axis) In the detection method, the weld line is substantially perpendicular to the two axes, the groove surface of the workpiece is held open with respect to one of the two axes (for example, the Z axis), and The position sensor is provided in the Z-axis direction, and the output of the position sensor is input to a computer, and the position of the weld line is detected by a program including the following steps. (A) A step of determining the relative position of the workpiece and the position sensor to a position Pa appropriately remote from one surface _F1 of the workpiece in the Z-axis direction. (B) A step of moving the relative position of the workpiece and the position sensor closer in the Z-axis direction from the Pa position, detecting the one surface _F1 , and storing information on the position Pb. (C) After the relative positions of the workpiece and the position sensor are displaced ΔXa from the Pb position in the X-axis direction, they are brought closer together in the Z-axis direction, and the one surface
Step of detecting _F1 and storing information of its position Pc. (D) After moving the relative position of the workpiece and the position sensor away from the Pc position in the Z-axis direction,
Displace △Xb in the X-axis direction, and further displace the Z
A step of detecting the other surface _F2 by approaching it in the axial direction and storing information on its position Pd. (E) After the relative positions of the workpiece and the position sensor are displaced ΔXa from the Pd position in the X-axis direction, the workpiece and the position sensor are moved closer together in the Z-axis direction, and the position sensor is moved toward the other surface.
Step to detect F ₂ and store information of its position Pe. (F) From the information of each position Pb, Pc, Pd, Pe,
Step to calculate the position Po of the intersection line of F ₁ and F ₂ . (G) The relative position of the workpiece and the position sensor is
Step to position to Po position. (H) A step of moving the relative position of the workpiece and the position sensor closer in the Z-axis direction from the Po position, detecting the groove surface, and storing information on the position _P1 . (I) A step of moving the relative position of the workpiece and the position sensor away from the _P1 position by _ΔZ2 in the Z-axis direction. (J) A step of displacing the relative position of the workpiece and the position sensor by ΔX from the position of step (I) in the X-axis direction and in either direction. (K) A step in which the relative positions of the workpiece and the position sensor are brought closer in the Z-axis direction from the position of step (J), the groove surface is detected, and information on the position _P2 is stored. (L) A step of determining the direction of inclination of the groove surface from the information of both the positions P ₁ and P ₂ . (M) As a result _of the step (L), the X
The groove surface displaced by ΔX in the axial direction is sequentially detected, and the information on the position Pn is stored, and each time the position Pn is detected, the step is calculated from the information on the detected positions Pn- ¹ and Pn. A step of determining whether the direction of inclination of the groove surface in (L) has become opposite. (N) If the direction of the slope of the groove surface is reversed in step (M), the detection position
A step in which the position of the groove surface slightly returned in the opposite direction to the direction in which it was displaced by ΔX in step (M) from Pn is calculated as the position P _f2 of the weld line.