JPH0122069B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is an automatic welding device that controls the position of a workpiece and a position sensor along at least two intersecting translation axes. The present invention relates to a method for detecting the position of a weld line of a corner joint when

(Prior art and its problems) Conventionally, methods for detecting the positions of butt weld lines and fillet weld lines are known, for example, in JP-A-54-15441 and JP-A-54-119353. In these conventional methods, a position sensor is first positioned above the groove surface of the workpiece, and one point on both groove surfaces is detected, and the position of the weld line is determined based on the two-point position information and the groove angle. It is intended for calculation.

However, when detecting the position of a weld line of a square joint, it is difficult to manually position the position sensor above the groove surface, especially when the workpiece is thin.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a method for detecting the position of a weld line of a square joint that does not require difficulty in manual operation even when the work is a thin plate. It is.

(General description of the invention) In this invention, the initial position sensor is not located above the groove surface of the corner joint, but is simply placed at an appropriate position above one surface of the workpiece, and the sensor automatically detects the groove surface. After finding a certain position above the surface and once positioning the position sensor at that position, detect each point on both groove surfaces one by one, and perform welding of the square joint from this position and the groove angle of the groove surfaces. This is a method of detecting the position of a line.

(Example) Although the automatic welding apparatus of this example will be explained as one that determines the relative position of the workpiece and the position sensor using rectangular coordinates, it is also possible to position using other coordinate systems, such as polar coordinates or cylindrical coordinates. Translation 2 that intersects the position information in coordinates at least
The position may be controlled by converting coordinates to axes (for example, rectangular coordinates), and the present 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).
is 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 φ axis direction 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 brake with 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 φ-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 φ-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 torch 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
The inclination angles of F ₂ and F ₂ are given in advance as α ₁ and β ₁ with respect to the Z axis, and the groove angles are α ₂ and
Assume that β ₂ .

(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) Command the torch 109 to move in the (-) direction of the Z-axis.

(5) Check whether the tip electrode of the torch 109 approaches the surface F ₁ and outputs a signal, and if there is an output, command the torch 109 to stop moving at that time, and also detect the signal at that time. Store the position information of position Pb in the computer.

(6) Command to return the welding point of torch 109 to point Pa, and if it returns, command to stop the movement of torch 109.

(7) A command is given to move the work W in the (+) direction of the X-axis by ΔXa, and when the movement by ΔXa is completed, a command is given to stop the movement of the work W.

Note that the value of ΔXa is set in advance so that the welding point of the torch 109 is located sufficiently above the surface F ₂ due to the movement of the workpiece W.

(8) Command the torch 109 to move in the (-) direction of the Z-axis.

(9) Check whether the tip electrode of the torch 109 approaches the surface F ₂ and outputs a signal, and if there is an output, command the torch 109 to stop moving at that time, and also detect the signal at that time. Store the position information of position Pc in the computer.

(10) Calculate the position P ₀ of the intersection line of surfaces F ₁ and F ₂ from the inclination angles α ₁ and β ₁ of surfaces F ₁ and F ₂ and the position information of each position Pb and Pc.

(11) Command the welding point of the torch 109 to be controlled to the position of point P ₀ . 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.

(12) Command the torch 109 to move in the (-) direction of the Z-axis.

(13) Check whether the tip electrode of the torch 109 approaches the groove surface and outputs a signal, and if there is an output, commands the torch 109 to stop moving at that time.

(14) Command the torch 109 to move by ΔZ in the (+) direction of the Z-axis. The value of ΔZ is
It is set to a small value.

(15) Command to move the workpiece W by ΔX in the (-) direction of the X-axis. Note that the value of ΔX is set according to the groove angles α ₂ and β ₂ and the value of ΔZ.
That is, in this example, ΔX is (ΔZ.
It is set slightly larger than Tanα ₂ ).

(16) Check whether the tip electrode of the torch 109 approaches one of the groove surfaces and outputs a signal while the workpiece W moves by the above-mentioned ΔX, and if there is an output, then the workpiece 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.

(17) Command to move the workpiece W in the (+) direction of the X-axis.

(18) Check whether the tip electrode of the torch 109 approaches the other groove surface and outputs a signal, and if there is an output, command to stop the movement of the workpiece W at that time, and at that time The position information of the detected position _P3 is stored in the computer.

(19) If no signal is output while the workpiece W moves by ΔX in step (16), a command is given to move the workpiece W in the (+) direction of the X-axis.

(20) Check whether the tip electrode of the torch 109 approaches the other groove surface and outputs a signal, and if there is an output, command to stop the movement of the workpiece W at that time, and at that time The position information of the detected position _P3 is stored in the computer.

(21) Command to move the workpiece W in the (-) direction of the X-axis.

(22) 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, command to stop the movement of the workpiece W at that time, and at that time The position information of the detected position _P2 is stored in the computer.

(23) The position information of P ₂ and P _{3 stored in steps (16) and (18), or the position information of P 3 and} P ₂ stored in steps (20) and (22), and the groove The position Pf of the welding line WL is calculated from the angles α ₂ and β ₂ .

This completes the position detection step of the welding line WL, and sets the position Pf as the welding point command position to the torch 10.
However, the actual welding point command position is determined by moving the welding point of the torch 109 from position Pf in the (+) direction of the Z-axis, taking into consideration the material, plate thickness, welding mode, etc. of the workpiece W. The welding point command position is a position slightly remote from the welding point.

The above description is an example, and for example, the position sensor may not be used also as the torch 109, but may be provided separately at a position that has a certain relationship with the torch 109.
It may be either a contact type or a non-contact type. Furthermore, in the step (15), the workpiece W is to be moved by ΔX in the (-) direction of the X-axis,
If the groove surface cannot be detected as a result, the groove surface closer to the position sensor, that is, the torch 109, is preferentially detected, and then the other groove surface is detected. Even if ₁ is the upper part of the groove surface of the left side member of the workpiece W in Fig. 3, we tried to shorten the detection time as much as possible, but if the groove is small, for example, Without going through such a process, one of the groove surfaces may be detected first, and then the other groove surface may be detected. It goes without saying that the technical scope of the present invention also includes the replacement of each component with equivalents.

(Effects of the Invention) Since the present invention is as described above, the operator does not have to perform the difficult operation of manually positioning the position sensor relative to the workpiece W at the P ₀ position above the groove surface. That is, the relative position is initially set to one surface F ₁ of the work W
If you position it at the upper position Pa, the rest will be done automatically.
The P ₀ position can be found. Therefore, if this P ₀ position is found, even if the workpiece W is a thin plate, the two points P ₂ and P ₃ on the groove surface can be easily detected, and the position information of the two points P ₂ and P ₃ can be obtained. The position of the weld line of the square joint can be determined from the groove angles α ₂ and β ₃ .

[Brief explanation of drawings]

Each of the figures shows an embodiment of the present invention.
The figure is an overall perspective view of the automatic welding device, FIG. 2 is an explanatory view of the main parts, FIG. 3 is an explanatory view of the operation, and FIG. 4 is a flow chart. In the figure, 100... automatic welding device, 105
... Fixture for workpiece W, 109 ... Torch (also used as position sensor), W ... Workpiece, WL ... Welding line, F ₁ , F ₂ ... Workpiece surface, Pf ... Welding line WL
position, 206... High voltage power supply for discharge (power supply for detection), 207... Current sensor, 400... Control box,
α ₁ , β ₁ ... inclination angle of surfaces F ₁ , F ₂ ; α ₂ , β ₂ ... groove angle.

Claims (1)

[Claims] 1. A case where a groove angle is given in advance in an automatic welding device that controls 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) In the method for detecting the position of a welding line in a square joint, the welding line is approximately perpendicular to the two axes, and the groove surface of the workpiece is perpendicular to one of the two axes (for example, the Z axis). The position sensor is held in the open state, 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 of the square joint is detected by a program including the following steps. how to. (A) A step of determining the relative position of the position sensor with respect to the workpiece at a position Pa appropriately remote from one surface of the workpiece in the Z-axis direction. (B) the relative positions of the workpiece and the position sensor are moved closer in the Z-axis direction from the position of the step (A), and one surface of the workpiece is detected;
Step to store information of the position Pb. (C) The relative position of the workpiece and the position sensor is moved away from the position of step (B) in the Z-axis direction, and then moved to a position appropriately remote from the other surface of the workpiece in the Z-axis direction. A step of moving by ΔXa in the X-axis direction. (D) moving the relative position of the workpiece and the position sensor closer in the Z-axis direction from the position of step (C) to detect the other surface of the workpiece;
Step to store information of the location PC. (E) From the inclination angles α ₁ and β ₁ of both surfaces of the workpiece and the position information of each position Pb and Pc, calculate the position P ₀ of the intersection line of both the surfaces, and calculate the relative position of the workpiece and the position sensor. a step of locating the position at the P ₀ position; (F) The relative position of the workpiece and the position sensor is moved closer in the Z-axis direction from the position of step (E), the groove surface is detected, and the position P ₁
A step that stores information. (G) Adjust the relative position of the workpiece and the position sensor by ΔZ from the position of step (F).
Axially remote step. (H) Displace the relative position of the workpiece and the position sensor from the position of step (G) in the X-axis direction, detect both groove surfaces of the workpiece, and determine the positions P ₂ and P Step ₃ to store information. (I) Groove angles α ₂ , β ₂ and positions of both groove surfaces
A step of calculating the position Pf of the welding line from the information of P ₂ and P ₃ .