JPH1080768A - Control method for fillet multi-layer welding robot system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To move a robot while applying real time tracking and also changing aimed position in accordance with the thermal deformation of a work in a fillet multi-layer welding. SOLUTION: By using a laser beam sensor mounted to a robot and detecting work faces H1, H2 thermally deformed, its intersecting point (fillet position) Oob is obtained as a reference point of tracking. A reference object position Qob =Δ(Δx-Δy) set for work faces H1, H2 before thermal deforming is changed to Qob corresponding to a thermally deformed quantity. The position of Qob , by converting a reference position shift data (Δx, Δy) to the data on the oblique coordinate in which lines yob , xob showing the faces H1, H2 are taken for the coordinate, are obtained as remaining apexes of a parallelogram having three points Oob , Vob , Uob for apexes. Further, a point Qob (γ) or a point Qob , at which the point is slightly corrected based on an appropriate rule, may be set to be the object position in consideration of thermal deformation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot equipped with a laser sensor and an arc welding torch at a hand (hereinafter referred to as a welding robot or simply a robot) and a system provided with a robot controller. More specifically, the present invention relates to a technique for causing a welding robot to perform a tracking operation in consideration of deformation of a joint at the time of multi-layer welding using a laser sensor using a laser sensor.

[0002]

2. Description of the Related Art A technology in which a laser sensor is mounted on a robot together with a torch for arc welding, and the robot performs tracking of the welding line using data obtained by sensing the welding line in advance, is a technology of a welding robot. Widely known as real-time tracking. Attempts have also been made to apply real-time tracking control to a robot that performs multi-layer welding.

As schematically illustrated in FIG. 1, the first, second, third,..., N-th (N; total bead) (The number of layers), the first layer, the second layer, the third layer,..., The N-th layer of beads A1, A2, A3,. It is done in. Generally, the trajectory of the target position at the time of forming each bead layer is not the same. Here, the “target position” refers to the position of the tip of the welding torch required for performing appropriate welding (usually coincides with the position of the tip of the tool of the welding robot).

In the case of performing multi-layer building at the corner, it is customary that the trajectories B1 to B1 'of the target position of the first layer substantially coincide with the position of the fillet line. As shown by B2 'and B3 to B3', a position is selected which is substantially apart from the position of the fillet line along the surface of each of the works W1 and W2 by a distance corresponding to the bead thickness.

The trajectories B1 to B1 'of the target positions of the first layer are:
Applying real-time tracking using a laser sensor to the first movement cycle of the welding robot can be realized relatively easily. This is because at the time of welding the first layer, the laser sensor only has to sense the corner where no weld bead is formed and detect the corner line position (a line representing the position of the corner; the same applies hereinafter). In contrast, 2
At the time of welding after the layer, since the corner is covered with the weld bead formed in advance, it is impossible to directly detect the corner line position with the laser sensor.

Therefore, the corner line position is directly detected by a laser sensor, and a shift amount Δ (generally, a vector amount having two components of Δx and Δy) previously set as a shift amount on a rectangular coordinate system is added thereto. The trajectories B2 to B of the target positions in the second and subsequent layers are determined in real time
It has been difficult to adopt the method of realizing 2 ′, B3 to B3 ′.

There is a method of accumulating data of the corner line position during tracking of the first layer and using the data at the time of welding for the second and subsequent layers. However, a large amount of data is required to accurately reproduce the corner line position. Data must be stored, which is not a convenient method.

As a technique that can solve such a problem,
It has been proposed to indirectly determine the corner line position using a laser sensor (see JP-A-8-16221). If this proposal were to be applied to the above example, the corner line positions would be changed to the surfaces G1, G2 of the workpieces W1, W2 providing the corners.
The target position (the target path of the tool tip point) is determined by adding the shift amount Δ (Δx, Δy) previously set as the shift amount on the orthogonal coordinate system to the obtained intersection line position. Become.

[0009]

The above-mentioned improved technique is excellent in that it makes it easy to apply real-time tracking using a laser sensor even when welding the second and subsequent layers, and that there is no need to store a large amount of data. ing. However, when this is actually applied to the multi-layer welding at the corners as shown in FIG. 1, it is not uncommon that the target position during actual welding is slightly shifted, and the expected welding accuracy cannot be obtained.

[0010] It is considered that the cause of such a shift of the target position is that the works W1 and W2 constituting the joint are deformed by the influence of heat generated by the arc discharge. FIG. 2 is a schematic diagram for explaining the example shown in FIG. As shown in the figure, the surface G1 of the workpiece W1, which was located at the position indicated by the broken line before the start of welding,
It has the property of being thermally deformed inward and inclined with the progress of multi-layer welding (indicated by G1 → H1). Although not shown, thermal deformation can also occur in the horizontal plane G2 of the work W2.
Generally, which work surface is deformed depends on the work W
It is a case-by-case, depending on the thickness, material, heating condition, etc. of 1, W2.

Considering now a target position B2 at the time of welding the second layer illustrated in FIG. 1 as an example, according to the conventional technology (including the above-mentioned improved technology), the target position B2 is determined before the start of welding. Based on the position G1, the position shift amount Δ2 is set based on the corner line position B1 (detected by the laser sensor). For example, when a coordinate system is set in which the directions of G1 and G2 are the Y axis and the X axis, respectively, the position shift amount Δ2 for specifying the target position B2 is specified by the vector amount Δ2 (0, d). Here, d is the distance between the corner line position B1 and the target position B2.

When the target position Bi of the i-th layer (i = 1, 2, 3,... N) is determined for the N-layer multi-layer welding by the same designation method, the following equation (1) is used. The components Δix and Δiy of the position shift amount Δi to be shifted are set in advance. In the example of FIG. 2, naturally, Δ2x = 0 and Δiy = d.

Δi = (Δix, Δiy) (1) When the thermal deformation as shown in the drawing occurs, the target position (torch tip position) to be originally realized is indicated by reference numeral C2 instead of B2. Move to a position like that. However, in the above-described method of determining the target position, the target position remains at B2 even if there is thermal deformation, and a robot path such that the tip of the torch passes through position C2 cannot be realized. That is,
The conventional technology does not have the technical means to change the target position appropriately according to the thermal deformation, so it is difficult to solve the problem in cases where the thermal deformation is large or where the misalignment of the target position greatly affects the quality of welding. Had become.

Therefore, an object of the present invention is to make it possible to apply real-time tracking using a laser sensor even in the case of multi-layer fillet welding of the second and subsequent fillets, while responding to the thermal deformation of the work constituting the joint. It is an object of the present invention to provide a control method for determining a moving path of a robot while changing a target position. In addition, through this, the quality of fillet fillet welding is improved.

[0015]

SUMMARY OF THE INVENTION The present invention relates to a control method of a system in which a robot equipped with an arc welding torch and a laser sensor is controlled by a robot controller. By performing the movement and shift adjustment of the movement path in consideration of the thermal deformation of the work or the work surface in parallel,
This is a solution to the above technical problem.

The tracking operation is performed with reference to the position of the corner line. To detect the position of the corner line, the positions of the two work surfaces providing the corners are detected by using a laser sensor, and the tracking operation is performed. This is achieved by determining the position of the corner line based on that.

On the other hand, the detection results of the positions of the two work surfaces are used to control the shift amount of the movement path according to the thermal deformation of the work surface. In a preferred embodiment, the shift amount of the movement path with respect to the work surface without thermal deformation is set in the system in advance as the reference shift amount. The set reference shift adjustment amount is converted into a new shift adjustment amount based on the detection results of the positions of the two work surfaces, and the shift amount of the movement path is controlled according to the thermal deformation of the work surface.

In a typical embodiment, the reference shift adjustment amount is set as a two-dimensional reference shift adjustment amount, and is converted into a new two-dimensional shift amount based on the detection results of the positions of the two work surfaces. Thus, the shift amount of the moving path can be controlled according to the thermal deformation of the work surface.

In a preferred conversion method, two straight lines representing the positions of two work surfaces are read as values expressed on an oblique coordinate system constituted by coordinate axes, thereby obtaining a new two-dimensional shift. Conversion to quantity is performed. Further, after the replacement, the correction may be performed in a form including a distance adjustment from the detected corner line position.

According to the above configuration of the present invention, the target position can be changed in accordance with the thermal deformation of the work constituting the joint while applying real-time tracking using a laser sensor also in the multi-layer fillet welding of the second and subsequent fillets. It is possible to determine the movement route of the robot while doing so. Therefore, even if thermal deformation occurs with the progress of the corner multilayer welding, deviation of the target position is avoided.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is a main block diagram for explaining the overall configuration of a system including a robot controller which can be used in carrying out the present invention. As shown in the figure, the robot control device 30 for controlling the entire system includes:
A central processing unit (hereinafter referred to as a CPU) 31;
The U31 includes a memory 32 composed of a ROM, a memory 33 composed of a RAM, a nonvolatile memory 34, a robot axis controller 35, a teaching operation panel 38 having an LCD 37, and a general-purpose interface 39 for connection to an external device. Have been.

The ROM 32 stores a program for controlling the entire system including the robot controller 30 itself. This includes a program necessary for inputting various data for implementing the present invention on a screen in a mode described later. A part of the RAM 33 is used for temporarily storing data for processing performed by the CPU 31. Further, in order to implement the present invention, some buffer registers for storing sensing data, path correction data, and the like, which will be described later, are set in the RAM 33. Non-volatile memory 3
In 4, a register for storing position data and a parameter for determining the path shift amount at the time of multi-layering is set.

Each servo motor provided in each axis mechanism of the robot 40 is connected to the robot axis controller 35 via a servo circuit 36. The external devices connected to the general-purpose interface 39 include a power supply device 50 for the arc welding torch 2 mounted on the tip of the robot 40 and the laser sensor 3 for performing real-time tracking.

Although the structure, function, measurement principle, and the like of the laser sensor are well known, the outline will be described with reference to FIGS. FIG. 4 illustrates a main configuration of a laser sensor used in the present embodiment.
It comprises a projection unit 10 and a light detection unit 13. The projection unit 10 includes a laser oscillator 11 and an oscillating mirror (galvanometer) 12 for beam scanning, and the light detection unit 13 includes an optical system 14 for imaging and a light receiving element 15.

On the other hand, the laser sensor control unit 20 includes a mirror driving unit 21 for oscillating the oscillating mirror 12, and a laser driving unit 2 for driving the laser oscillator 11 to generate a laser beam.
2. A signal detection unit 23 that detects an incident position (reflection point) S of the laser beam 5 on the object based on the light receiving position of the light receiving element 15 is connected. These are connected to the general-purpose interface 39 of the robot controller 30 via the line 24.
(See FIG. 3).

When the laser sensor 3 receives an operation command from the robot controller 30 via the line 24, the laser driver 22 drives the laser oscillator 11 to generate the laser beam 5. At the same time, the swing of the swing mirror 12 is started by the mirror drive unit 21. Thereby, the laser beam generated from the laser oscillator 11 is scanned on the object surface G.

The laser beam diffusely reflected at the reflection point S on the object surface G forms an image on the light receiving element 15 by the optical system 14 according to the position of the reflection point S. The light receiving element 15 includes a one-dimensional CCD array which is a split type element and a light receiving element, or a position detector (PS) which is a non-division type and integrating type element.
D; Position Sensitive Detector) or a CCD camera having a two-dimensional CCD array.

Here, a one-dimensional CC is used as the light receiving element 15.
It is assumed that a D array is used. The light (image of the reflected light) hitting the light receiving surface of the light receiving element 15 is converted into an electric charge,
It is stored in that cell. The electric charge accumulated in the cell is changed by one every predetermined period in accordance with the CCD scanning signal from the signal detector 23.
The signals are sequentially output from the end, and sent to the robot controller 30 via the signal detector 23 and the line 24.

The scanning cycle of the CCD is set sufficiently shorter than the scanning cycle of the oscillating mirror 12 (for example, several hundredths).
The change of the swing angle of the swing mirror 12 and the CCD
The transition of the element output state can be grasped at any time. C
The CD element output state is the cell position (cell number) where the output is maximum
The position of the cell to which the reflected light is applied is detected.
From this position, the position of the reflection point S on the sensor coordinate system is obtained.

FIG. 5 shows a detection position s in the light receiving element 15.
, The position (Xs, Ys) of the reflection point S on the sensor coordinate system
FIG. 7 is a diagram for explaining a method of obtaining (). It is assumed that the origin (0, 0) of the sensor coordinate system is on a line connecting the center of the optical system 14 and the center point of the light receiving element 15, and this line is defined as a Y axis, and an axis orthogonal to the Y axis is defined as an X axis.

The distance from the origin of the sensor coordinate system to the center of the optical system is L1, and the distance from the center of the optical system to the light receiving element 15 is L1.
Is the distance from the sensor origin to the center of oscillation of the oscillating mirror 12 in the X-axis direction, and the distance from the sensor origin to the center of oscillation of the oscillating mirror 12 is L0.
The angle of the reflected light of the laser beam from the oscillating mirror 12 with respect to the Y-axis direction is θ, and the light receiving position on the light receiving surface of the light receiving element 15 is s.

Then, the coordinate position (Xs, Ys) of the reflection point S of the laser beam 5 can be obtained by the following equations (2) and (3). Xs = s ・ [(L1−L0) · tan θ + D] / (xa + L2 · tan θ) (2) Ys = [L1 · s + L2 · (L0 · tan θ−D)] / (s + L2 · tan θ) (3) The position (Xs, Ys) of the reflection point S obtained in the sensor coordinate system
) Is a coordinate system recognized by the robot using the posture data of the robot and the calibration data (data representing the relationship between the sensor coordinate system and the robot coordinate system). Σw O
-XYZ) is converted to three-dimensional data. A series of data obtained in each scanning cycle of the laser beam 5 is analyzed by software processing in the robot controller 30 and, for example, the position of the laser beam scanning locus on the surface G (calculated from the positions of the plurality of reflection points S) Is required.

Next, FIG. 6 is a sketch showing the outline of the overall arrangement when the present invention is applied to the case shown in FIG.
As shown in the figure, a welding torch 2 and a laser sensor 3 are mounted on the hand of the robot designated by reference numeral 1. Reference numeral 5 denotes a robot tool tip point set at the tip position (torch tip) of the welding wire 4 fed from the welding torch 2.

This figure shows a state where the welding of the second layer is in progress, and the bead A2 of the second layer is formed partway. Laser beam LB projected from laser sensor 3
In order to sense a region preceding the torch tip 5, a surface H1 (G
1) A bead A1 of the first layer already formed along the corner line 7 and a surface H2 (G
Light spot trajectories 6a and 6 that repeatedly pass through the three of 2)
b, 6c. Note that H1 (G1) and H2 (G2)
Indicates that the surfaces G1 and G2 before the start of welding may move due to thermal deformation after the start of welding (the same applies hereinafter).

As shown by the arrows, the welding robot
It is assumed that a movement path that moves from the corner start point P to the corner end point P ′ along the corner line 7 with the welding torch 2 ignited is taught. By regenerative operation, the robot
The moving operation using P 'as the teaching path is repeated N times equal to the total number of layers, but the actually realized moving path is different depending on the difference in the target position as described above. What is important here is that the influence of thermal deformation is taken into account when changing the path (changing the shift direction and distance from the corner line 7) depending on the difference in the target position.

In the present embodiment, the present invention is implemented by the following method. (1) The predicted maximum total number N in the nonvolatile memory 34
The number of registers RG1, RG2,... RG corresponding to max
Nmax and an address designation counter for designating a register number are set in advance. (2) The reference shift amount Δi for welding the i-th layer is stored in advance in the i-th register RGi. Here, the reference shift amount Δi refers to “the target positions B1 to B4 considered to be optimal when no thermal deformation occurs” (hereinafter, referred to as “reference target positions”) as the corner lines 7 (the laser sensor 3). ) Is expressed by a two-dimensional shift amount with reference to the position of (.). (3) The reference shift amount Δi is calculated based on the corner line 7 on the orthogonal coordinate system Σw (work coordinate system O-XYZ) set for the robot.
Shift amount Δ in the X-axis direction based on the position of (teaching path)
x and the value representing the shift amount Δy in the Y-axis direction are, for example, mm
It is set in advance by operating the teaching operation panel 38 in units. Here, it is assumed that the normal directions of the work surfaces G1 and G2 before welding are parallel to the Y axis and the X axis of the coordinate system Σw, respectively.

(4) As an example, the total number of layers N = 4, and the reference shift amount Δ1 representing the reference target positions B1 to B4.
.DELTA.4 are set as shown in FIG. Register R specified by each address specification counter value 1, 2, 3, 4
The data stored in G1 to RG4 is as follows. RG1; (0, 0) RG2; (0, d) RG3; (d, 0) RG4; (d, d) (5) In any of the first to fourth layers, a corner is formed by using the laser sensor 3. The position of the part line 7 is detected, and real-time tracking with position correction based on the position is executed.
This tracking correction is based on the teaching path (planned corner line position).
This is for compensating the deviation of the position of the corner line 7 actually detected by the laser sensor 3, and is different in purpose from the position shift for changing the target position for each layer welding.
The two are in a relation to be added when determining the torch tip position.

That is, in the present embodiment, “torch tip position” = “position on teaching path” + “tracking correction amount”
The position of the tip of the torch when the robot moves is determined based on the relationship of + "shift amount for determining the target position". And
Regarding the third item on the right side, “shift amount for determining target position”, the technical idea of the present invention is applied, and thermal deformation of the work is taken into consideration.

(6) The position of the corner line 7 described in the above (5) is obtained by changing the position of the intersection line between the surfaces H1 (G1) and H2 (G2) by laser beam scanning to the surfaces H1 (G1) and H2 ( G2)
At the intersection of two straight lines represented by the light spot trajectories 6a and 6b (see FIG. 6). There are two reasons for employing such an approach. One is to make it possible to estimate the position of the corner line even if the corner line 7 is hidden by the bead during the welding of the second and subsequent layers, and the other is to make the surface H1 (G
1), to know the thermal deformation of H2 (G2). The latter detection result is reflected in real time in the above-mentioned (5) “shift amount for determining target position”.

(7) The planes H1 (G1) and H2 (G2) are defined as intersection points of two straight lines represented by the light spot trajectories 6a and 6b.
In order to obtain the intersection line position of the surface H, as shown in FIG.
Parameters that can specify ranges L1 and L2 that are appropriate distances from the position of the corner line 7 (there is no possibility of being covered with the bead A1 or the like) on 1 (G1) and H2 (G2) are set in advance. .

As the parameter, for example, as shown, φs which defines a fixed angle range at both ends of the full scanning angle range φfull of the laser beam can be adopted. It is also possible to specify the time measured from the time when both ends of the scanning angle range are reached. Note that FIG. 8 shows a state in which only the surface G1 is thermally deformed to H1, but even if the surface G2 is thermally deformed, there is no particular problem in specifying the ranges L1 and L2 in such a manner.

(8) There are various ways to change the target position in accordance with the thermal deformation of the surfaces H1 (G1) and H2 (G2). The point is that the equivalence of the target position before and after the thermal deformation is important. May be changed by an appropriate method so that the position is substantially maintained. Various methods can be adopted as the change method. Here, a method using an oblique coordinate system will be described with reference to FIG.

In this method, the surfaces H1 (G1), H2 (G
The straight line (corresponding to 6a and 6b) detected in 2) is regarded as a coordinate axis of a two-dimensional oblique coordinate system representing thermal deformation, and the set value Δi of the reference software amount is interpreted again to determine the target position. The target position is obtained by the following geometric calculation. 1. As shown in FIG. 9, when Q is a reference target position representing an arbitrary set value Δi (Δx, Δy) of the reference software amount, QV is a perpendicular line dropped from point Q to surface G1, and QU is point Q.
From the surface G2. Surfaces G1 and G2 are Y
Considering a coordinate system o-xy corresponding to the axis and the X axis, the y coordinate value of V is Δy and the x coordinate value of U is Δx.

2. As shown (exaggerated), face G
When G1 and G2 undergo thermal deformation and become surfaces H1 and H2, y
Axis and x axis correspond to the planes H1 and H2, and the oblique coordinate system Oob-x
Ask for obyob. The position and direction of the xob axis and the yob axis are detected by the laser sensor 3, and the position of Oob is obtained from this. The displacement of the corner position Oob due to thermal deformation is so small as to be negligible (however, the present invention can be applied even if there is some displacement).

3. xob such that oobUob = oU (= Δx)
Find the point Uob on the axis. 4. Point Vob on the yob axis such that oobVob = oV (= Δy)
Ask for. 5.3 The remaining vertices Qob of the parallelogram having the three points oob, Vob, and Uob as vertices are obtained, and these points are set as target positions. The origin (the corner line position detected by the laser sensor) oob of the oblique coordinate system expressed on the above-described work coordinate system O-XYZ and the X and Y coordinate values of the point Qob obtained above are respectively (pxob, pyob)
), (Qxob, qyob), the shift amount δi (δix, δiy) in consideration of the thermal deformation is given by the following equations (4) and (5). δix = qxob−pxob (4) δiy = qyob−pyob (5) The diagonal line oobQ of the parallelogram oobUobQobVob
Point Qob (γ) on ob where oobQob (γ) = γoobQob
May be set as the target position. Here, γ is a coefficient for adjusting the distance from the corner line position oob to the target position measured, and is generally set to a value close to 1. Alternatively, a point Qob 'where oobQob' = | Δi | is determined on the diagonal line oobQob, and this point may be set as the target position.

In the following, on the premise described above, FIG.
With reference to the flowchart of FIG. It should be noted that only the processing relating to the detection operation by the laser sensor and the path movement of the robot will be described, and the processing relating to the control of the welding torch and the like will be omitted.

The process is started by setting the initial value of the address designation counter value i for designating the register RGi to 1. First, the laser sensor 3 is started (step M1), an operation command sentence of the operation program is read, and a process for moving the robot toward the teaching point position P is started (step M2). The work W1, W2
Is detected (yes output in step M3), immediately using the detection data of the laser sensor 3 obtained in the above-described scanning angle range φs, the appropriate points included in the ranges L1 and L2 (see FIG. 8) (at least 2 each))
The positions (including direction information) of the straight lines represented by L1 and L2 are obtained and stored in the buffer memory (step M4).

The straight line obtained in step M4 corresponds to the yob axis and the xob axis shown in FIG. The processing procedure of converting the sensor data obtained by the laser sensor 3 into the coordinate system set for the robot (the current position data of the robot and the coordinate system conversion data are used) and the data of the positions of a plurality of points are used. Since the processing procedure for obtaining a straight line represented by the above point is well known, a detailed description thereof will be omitted.

Next, the position oob of the corner line 7 is determined in step M4.
Is obtained as the position of the intersection of the two straight lines (the yob axis and the xob axis) obtained in step (step M5). Then, a tracking correction amount for compensating the deviation amount from the teaching path is obtained from the data of the obtained position oob of the corner line 7 and stored in the buffer memory (step M6).

Next, data of the reference position shift amount Δi stored in the register RGi designated by the address designation counter value i is read (step M7). And
Using the read data of the reference position shift amount Δi, the xob axis obtained in steps M4 and M5, the data representing the position / direction of yob, and the data of the corner position oob, the position for determining the target position. The shift amount δi is calculated (step M8). The calculation contents of the position shift amount δi are as described above.

When the position shift amount δi is obtained, the robot movement target position is calculated by the teaching path position + the tracking correction amount + the position shift amount δi. The movement command created based on the calculation result is output to the servo system (Step M9).

If the process for causing the robot to reach the teaching point P 'is not completed (No output in step M10), the process returns to step M4 and repeats steps M4 to M10. If the process for the robot to reach the teaching point P 'has been completed (yes output in step M10), the process proceeds to step M11, where the address designation counter value i is incremented by one.

Next, it is checked whether or not the multi-layer welding has been completed for the total number of layers of the multi-layer welding (here, four layers) (Step M12). Returning to M2, the processing cycle described above is repeated. When the multi-layer welding of four layers is completed,
Since a yes output is issued in step M12, the process is terminated after stopping the laser sensor 3 and the robot.

Through the above processing, regarding the movement of the robot during welding of the first to fourth layers, the robot path is determined in real time while determining the target position in consideration of the thermal deformation of the work in parallel with the real-time tracking of the robot. You can decide.

[0055]

According to the present invention, the real-time tracking using the laser sensor is applied to the fillet multi-layer welding of the second and subsequent fillets while changing the target position according to the thermal deformation of the work constituting the joint. You can now determine the path of the robot. In addition, through this, it is possible to improve the willingness of fillet multi-pass welding performed under conditions that easily cause thermal deformation.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating multi-layer welding on a fillet portion.

FIG. 2 is a schematic diagram illustrating deviation of a target position due to thermal deformation in the example shown in FIG. 1;

FIG. 3 is a main block diagram illustrating an overall configuration of a system including a robot control device that can be used when implementing the present invention.

FIG. 4 is a diagram illustrating a main configuration of a laser sensor used in the present embodiment.

FIG. 5 is a diagram illustrating a measurement principle of a laser sensor.

FIG. 6 is a perspective view schematically showing an overall arrangement in the embodiment.

FIG. 7 is a diagram for explaining setting contents of reference shift amounts Δ1 to Δ4 representing reference target positions B1 to B4 in the embodiment.

FIG. 8 shows planes H1 (G1) and H2 using a laser sensor.
It is a figure explaining parameter setting for calculating the intersection line position of (G2).

FIG. 9 is a diagram illustrating a calculation method for determining a shift amount δi in consideration of thermal deformation.

FIG. 10 is a flowchart illustrating an outline of processing contents when performing multi-layer welding in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Robot hand part 2 Welding torch 3 Laser sensor 4 Welding wire 5 Torch tip position (tool tip point) 6a, 6b, 6c Light spot locus 10 Projection unit 11 Laser oscillator 12 Oscillating mirror (galvanometer) 13 Detecting unit 14 Imaging 15 Light receiving element 20 Laser sensor control unit 21 Mirror drive unit 22 Laser drive unit 23 Signal detection unit 24 Line 30 Robot controller 31 CPU 32 ROM 33 RAM 34 Non-volatile memory 35 Axis controller 36 Servo circuit 37 LCD 38 Teaching Operation panel 39 General-purpose interface 40 Robot (servo motor of main body mechanism) 50 Power supply device A1 to A3 Welding bead B1 to B4 (Reference) Target position C2 (thermal deformation is considered) Target position G1, G2 Work surface (start welding) Before) H1, H2 Work surface (after welding start) S Incident position (reflection point) W1, W2 Work

Continued on the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H01S 3/00 H01S 3/00 F

Claims (5)

[Claims] An arc welding torch, a laser sensor,
A robot equipped with the arc welding torch and the laser sensor, and a control method in a fillet multilayer welding robot system for performing fillet multilayer welding using a system including a robot controller, wherein the robot has a fillet multilayer welding. The path movement during welding execution
In parallel with the tracking operation based on the detection of the position of the corner line representing the corner, the movement path of the robot so that the target position of the arc welding torch according to the welding of each layer of the fillet multilayer is realized. The position of the corner line is detected using the laser sensor to detect the position of the two work surfaces providing the corner, and the position of the two work surfaces is detected. The position of the corner line is calculated based on the position of the corner line, and the shift amount for adjusting the movement path is determined based on the detection result of the position of the two work surfaces. A control method for the fillet multi-layer welding robot system, wherein the control is performed according to the following. 2. A shift amount of the movement path with respect to the work surface that is not thermally deformed is set in the system in advance as a reference shift amount, and the set reference shift adjustment amount is set to a position of the two work surfaces. 2. The fillet multi-layer fillet according to claim 1, wherein the shift amount of the moving path is controlled in accordance with thermal deformation of the work surface by converting the shift amount into a new shift adjustment amount based on a detection result. 3. Control method in welding robot system. 3. The system according to claim 2, wherein the reference shift amount is previously set in the system as a two-dimensional reference shift amount based on the corner line position, and the set two-dimensional reference shift adjustment amount is set to the two workpieces. 2. The shift amount of the moving path according to claim 1, wherein the shift amount of the moving path is controlled in accordance with a thermal deformation of the work surface by converting the shift amount into a new two-dimensional shift amount based on a detection result of the position of the surface. Control method in fillet multilayer welding robot system. 4. The method of claim 2, wherein the two-dimensional reference shift adjustment amount is
The conversion to the new two-dimensional shift amount is performed by reading two straight lines representing the positions of two work surfaces as values expressed on an oblique coordinate system configured as coordinate axes. The control method in the fillet multilayer welding robot system according to claim 3. 5. The method of claim 2, wherein the two-dimensional reference shift adjustment amount is
The two straight lines representing the positions of the two work surfaces are read as values expressed on an oblique coordinate system configured as coordinate axes, and further corrected to include the distance adjustment from the detected corner line position. 4. The control method according to claim 3, wherein the conversion into the new two-dimensional shift amount is performed.