JP2001105137A - Off-line teaching device for welding and method of manufacturing for large structure using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an off-line teaching device for welding with which the burden on an operator is minimized and the operation of a robot is accurately performed, and a method of manufacturing a large structure or which a stable welding is executed by using the device. SOLUTION: Information on a welding robot, its peripheral equipments, a welding torch mounted on the robot, and a work welded by the robot is stored as a respective three-dimensional model in a storage device of a computer 13 or an external storage device. Stored information is displayed on a display to enable a teaching and simulation of operations of the robot and the peripheral equipments. The computer 13 is provided with a finding means for a section shape which finds a section shape of a fused and bonded metal part laminated on a welded part on the basis of a welding condition set on each path as a path-generation means for a multi-layer welding to be executed by the robot, and a generation means for a next path-position which generates the position of a next path on the basis of a result obtained by the calculation means for the section shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding off-line teaching apparatus applied when welding and assembling a large structure using a robot, and a method for manufacturing a large structure using the same.

[0002]

2. Description of the Related Art Conventionally, information relating to a welding robot, its peripheral devices, a welding torch attached to the robot, and a work to be welded by the robot are stored in a storage device of a computer or an external storage device.
2. Description of the Related Art There is known a technique of storing dimension models, displaying them on a display device, and teaching and simulating operations of the robot and peripheral devices.

[0003] The teaching methods of such a robot are roughly classified into two types: a method of teaching directly using a robot and a method of teaching offline.

In the former direct teaching method, an operator operates a robot controller to actually operate a robot, aligns a work with a tool such as a welding torch provided at the tip of a robot arm, and adjusts the position. This is stored in the controller. In this method, the burden on the operator is large because it depends on the skill of the operator.

In the latter method of teaching offline, the above teaching method is performed on a three-dimensional model display of a computer. In this method, an operator operates a robot model on a computer to create teaching points. In multi-layer welding with many teaching points, the burden on the operator is large.
Further, data at the time of design is used for creating a model of a work. In this case, since the deformation of the workpiece during welding is not taken into account, when the offline teaching data is actually reproduced by the robot, the operation may not be performed according to the intention of the operator.

[0006]

In the teaching of multi-layer welding by a robot, since there are many teaching positions, the burden on the operator is large. Further, in the conventional offline teaching device, since welding deformation is not taken into account, when the offline teaching data is reproduced by the robot, an error occurs between the teaching position and the operating position of the robot.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an offline teaching device for welding that can reduce the burden on an operator and accurately perform a robot operation.

Another object of the present invention is to provide a method of manufacturing a large-sized structure capable of performing a stable welding operation using the above-described apparatus.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a welding robot, its peripheral devices,
Information on the welding torch attached to the robot and the work to be welded by the robot is stored as a three-dimensional model, respectively, and displayed on a display device to enable teaching and simulation of the operation of the robot and peripheral devices. In the offline teaching device for a welding robot, the computer is configured to generate a multi-pass welding path to be performed by the robot, as a means for generating a weld metal portion to be stacked on a welding site based on welding conditions set for each pass. Off-line teaching for welding, comprising: a cross-sectional shape calculating means for calculating a cross-sectional shape; and a next pass position generating means for generating a position of a next pass based on a result obtained by the cross-sectional shape calculating means. Provide equipment.

According to the second aspect of the present invention, information on a welding robot, peripheral devices thereof, a welding torch attached to the robot, and a work to be welded by the robot are three-dimensionally stored in a storage device or an external storage device of the computer. In the off-line teaching device of a welding robot, which stores the models as models, displays them on a display device, and teaches and simulates the operation of the robot and peripheral devices, the computer includes a multi-layer buttering welding to be performed by the robot. Teaching point generating means for generating a teaching roll on the work surface so that the interval between the welding paths is an arbitrary distance; and the above-mentioned work so that the work surface at the teaching roll is at an arbitrary angle. Calculate the position of each motion axis of the positioner equipped with To provide offline teaching apparatus for welding, characterized in that it includes a work shaft position calculating means.

According to the third aspect of the present invention, information on a welding robot, peripheral devices thereof, a welding torch attached to the robot, and a work to be welded by the robot are three-dimensionally stored in a storage device or an external storage device of the computer. In the off-line teaching device of a welding robot, which stores the models as models, displays them on a display device, and teaches and simulates the operations of the robot and the peripheral devices, the computer is set to the taught welding path. Welding deformation amount calculating means for calculating the welding deformation amount of the work based on the welding conditions; and shape changing means for changing the shape of the three-dimensional model of the work based on the deformation amount obtained by the welding deformation amount calculating means. And providing an offline teaching device for welding characterized by comprising: That.

According to a fourth aspect of the present invention, in the welding off-line teaching apparatus according to the third aspect, the means for generating the paths for the multi-pass welding includes determining the position of the next pass based on the amount of deformation of each pass by welding. An offline teaching device for welding is provided, comprising a next pass position generating means for generating.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a large-scale structure by assembling a plurality of members formed of a three-dimensional curved surface by welding, wherein at least one of the members is formed by machining a groove. While providing a plurality of projections having a plane serving as a reference surface, while performing welding of the above members,
An operation instruction for detecting the protrusion is added to teaching data for a robot created by the offline teaching device for welding according to any one of claims 1 to 4, and the teaching data is reproduced by the robot. The present invention also provides a method for manufacturing a large-sized structure, characterized in that the teaching data is corrected by detecting three planes of the projections by a sensor, and welding is performed based on the corrected teaching data.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the basic configuration of an offline teaching device. This offline teaching device uses a keyboard 1
1, mouse 12, computer 13, display 1
4. An external storage device 15 is provided. In this offline teaching device, an input is performed using a keyboard 11 or a mouse 12, and the input robot or peripheral device, a welding torch attached to the robot, and a workpiece to be welded by the robot are formed on a display 14. Display as a model.

Next, the operator teaches the position and orientation of the robot or the end effector model of the robot displayed on the display 14 so that the computer 13 creates teaching data of the robot coordinate axes and outputs the teaching data to the external storage device 15. I do.

The computer 13 calculates a cross-sectional shape of a welded metal portion to be laminated on a welding portion based on welding conditions set for each pass, as means for generating multi-pass welding to be performed by the robot. A calculating section; and a next path position generating section configured to generate a position of a next path based on a result obtained by the section shape calculating section.

FIG. 2 is a flowchart showing a procedure for automatically generating a teaching point using such a device.

First, the keyboard 11 and the mouse 1 described above are used.
2, the workpiece shape and the welding conditions for each pass of multi-pass welding are input (S101). Thereby, a welding pass of the first layer of the multi-layered pile is generated based on the input information (S102). The generated number of passes is judged by the judging means whether or not the set number of passes has been reached. If the number of passes has not been reached (NO), the process proceeds to the next step, and the amount of deposited metal in the weld zone is determined from the welding conditions of the welding pass. Is calculated (S1
04). Next, the shape of the metal deposited on the weld is calculated (S105), and a welding pass for the next layer is generated based on the calculated shape (S106). In this manner, the steps (S103) to (S103) are performed by the number of times of the multi-pass welding.
106) is repeated, and when a predetermined number of passes is reached (S10)
3: YES), the process ends.

The method for calculating the amount of deposited metal in step (S104) will be described. In the case of GTAW, it is assumed that the wire supplied from the welding torch does not disappear during welding. At this time, the wire amount Vw supplied in a unit time is calculated using the wire diameter d, the welding speed Vt, and the wire supply speed Vf.

Vw = π × (d / 2) ² × Vf × Vt

Next, the method of calculating the shape of the deposited metal in step (S105) will be described.

At time t (0 ≦ t ≦ T), the amount of the deposited metal as the cross-sectional area S (t) of the deposited metal is:

## EQU2 ## If Vw = （S (t) dt and S (t) is a constant value S, S can be obtained from the above equation.

[0023]

(Equation 3)

FIGS. 3A and 3B are explanatory diagrams relating to the calculation of the formation of the deposited metal in the method of generating a welding path shown in FIG.

As shown in FIG. 3A, the groove angle θ (t), the torch attitude θ ₁ (t), and θ at time t
₂ (t) = θ (t) −θ ₁ (t), and assuming that the bead surface is perpendicular to the torch direction, the bead height H is

(Equation 4) Than

(Equation 5) Becomes

Further, as shown in FIG. 3 (B), bi the n-th layer (n ≧ 2) - De height _{H n} is a torch posture of the welding of the n-th layer θ ₁ (t), θ ₂ (t), the bead height H _n-1 of the (n-1) th layer and the torch posture are θ ₁ ′ (t), θ ₂ ′
When expressed using (t), the cross-sectional area S per unit time is expressed by the following equation.

[0027]

(Equation 6) From now on, the bead height Hn

(Equation 7) Becomes

FIG. 4 is an explanatory diagram of a method of calculating a teaching position in the method of generating a welding path shown in FIG.

As shown in FIG. 4, when calculating the welding path of the nth layer, the torch posture θ, the bead height H in the torch posture direction, and the bead height H ′ of the (n−1) th layer , The torch attitude θ ′, and the tip-base metal distance h,

(Equation 8) Becomes

As described above, according to the present embodiment, the teaching point of each pass of the multi-pass welding can be calculated by the computer, thereby reducing the burden on the operator and shortening the time for creating the teaching data. Can be.

FIG. 5 shows, as another embodiment of the present invention, a method of automatically generating teaching points for multi-layer buttering welding.

In this example, a teaching point generating means for generating a teaching point on a work surface so that an interval between welding paths is an arbitrary distance when a path for multi-layer buttering welding is generated, Operating axis position calculating means for calculating each operating axis position of the positioner on which the work is mounted so that the surface of the work is at an arbitrary angle.

In this case, a bead interval d of the multi-layer buttering welding is input as a welding condition, and a circle having a radius d from the vertex (center point) O of the groove is drawn. At this time, a teaching point P1 is generated at the intersection with the welding surface. Next, a circle having a radius d centered on P1 is drawn, and a teaching point P2 is generated at an intersection with the welding surface. Similarly, a circle having a radius d centered on the generated teaching point is drawn, and a teaching point is generated at the intersection with the welding surface.

According to the present embodiment, the teaching point of each pass in the case of application to multi-layered buttering welding is calculated using a computer, so that the burden on the operator is eliminated and the time for creating the teaching data is shortened. Can be.

In another embodiment of the present invention, off-line teaching data can be generated in consideration of welding deformation.

That is, the computer is configured to calculate a welding deformation amount of the workpiece based on the welding conditions set for the taught welding path, and a deformation amount obtained by the welding deformation amount calculating means. And a shape changing means for changing the shape of the three-dimensional model of the work based on the above.

In this case, first, the heat input by welding is calculated from the given welding conditions. The temperature distribution of the workpiece to be welded is calculated based on the heat quantity. Then
Deformation of the shape of the work is simulated by performing a thermal elasto-plastic stress analysis based on the temperature distribution of the work.
Change the dimensional model. Thereafter, offline teaching is performed by means similar to the above embodiment.

By such means as well, by predicting the welding deformation by calculation, it is possible to create teaching data in consideration of the welding deformation.

FIG. 6 shows a method of manufacturing a large structure using off-line teaching data as still another embodiment of the present invention.

In FIG. 6, a projection 63 having three flat surfaces serving as a reference surface for machining a groove portion 62 is attached to a vane 61 of a welding turbine runner which is a large structure. Depending on the performance of the NC machine used for machining the groove 62, the groove 62 of the vane 61 and the protrusion 63
The positional relationship between the planes is quantitatively guaranteed.

In the offline teaching device, the projection 63
When creating off-line teaching data using a three-dimensional model of a workpiece having the following, an operation command for sensing is added to the projection 63. Then, when the created offline teaching data is reproduced by the robot, the three planes of the protrusion 63 are detected by the sensor, and the offline teaching data is corrected and executed based on the detected error amount.

According to the manufacturing method described above, the position of a tool such as a welding torch attached to the tip of the robot arm is more accurate than in the conventional off-line teaching data, and a stable welding operation can be performed.

[0043]

As described above, according to the present invention, it is possible to automatically generate teaching data of multi-layer welding by a robot from given shapes of welding objects and welding conditions. In addition, by estimating the amount of deformation of an object due to welding from given welding conditions and correcting the teaching data, teaching data with high positional accuracy can be created. Furthermore, when the created data is played back by a robot, an accurate amount of robot operation can be realized by detecting an error amount with a sensor for a protrusion having a reference surface for groove preparation of a welding portion, and achieving stable operation. Welding work can be performed.

Further, according to the present invention, by accurately detecting the error amount existing between the offline teaching data and the actual machine and correcting the offline teaching data, the accuracy of the operation position of the robot can be improved and the stability can be improved. Welding work can be realized, and the manufacture of large structures can be suitably performed.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a configuration diagram of an offline teaching device of a robot.

FIG. 2 is a flowchart showing a procedure for generating a multipass welding pass by the offline teaching system shown in FIG. 1;

3A and 3B are explanatory diagrams relating to calculation of a shape of a deposited metal in the method of generating a welding path illustrated in FIG. 2;

FIG. 4 is an explanatory diagram of a method of calculating a teaching position in the method of generating a welding path shown in FIG. 3;

FIG. 5 illustrates another embodiment of the present invention and is an explanatory view of a method for calculating a teaching point in multi-layer buttering welding.

FIG. 6 is a diagram showing an embodiment of a method for manufacturing a large structure according to the present invention.

[Explanation of symbols]

 11 keyboard 12 mouse 13 computer 14 display 15 external storage device

Claims (5)

[Claims] 1. A storage device of a computer or an external storage device stores, as a three-dimensional model, information on a welding robot, peripheral devices thereof, a welding torch attached to the robot, and information on a work to be welded by the robot. In a welding robot off-line teaching device which displays them on a display device and enables teaching and simulation of the operation of the robot and peripheral devices, the computer generates a multi-pass welding pass to be performed by the robot. A cross-sectional shape calculating means for calculating a cross-sectional shape of a welded metal portion to be laminated on a welding portion based on welding conditions set in each pass; and a next pass based on a result obtained by the cross-sectional shape calculating means. Next path position generating means for generating the position of Offline teaching device for welding. 2. A storage device of a computer or an external storage device stores, as a three-dimensional model, information on a welding robot, peripheral devices thereof, a welding torch attached to the robot, and a work to be welded by the robot, respectively. In the off-line teaching device for a welding robot, which displays them on a display device to enable the teaching and simulation of the operation of the robot and peripheral devices, the computer generates a multi-layer buttering welding pass to be performed by the robot. As means, a teaching point generating means for generating a teaching roll on the work surface so that the interval of the welding path is an arbitrary distance, and a positioner mounted with the work so that the work surface at the teaching roll has an arbitrary angle. Operating axis position calculating means for calculating each operating axis position; An offline teaching device for welding, comprising: 3. A storage device of a computer or an external storage device stores, as a three-dimensional model, information on a welding robot, peripheral devices thereof, a welding torch attached to the robot, and information on a work to be welded by the robot. In the off-line teaching device of the welding robot that allows them to be displayed on a display device to teach and simulate the operation of the robot and peripheral devices, the computer is based on welding conditions set in the taught welding path, A welding deformation amount calculating means for calculating the welding deformation amount of the work; and a shape changing means for changing a shape of the three-dimensional model of the work based on the deformation amount obtained by the welding deformation amount calculating means. An offline teaching device for welding characterized by the following. 4. The off-line teaching device for welding according to claim 3, wherein the means for generating paths for multi-pass welding includes generating a next pass position based on a deformation amount of each pass by welding. An off-line teaching device for welding, comprising a generation unit. 5. A method for manufacturing a large structure by assembling a plurality of members constituted by three-dimensional curved surfaces by welding.
At least one of the above members is provided with a plurality of protrusions having a plane serving as a reference surface for machining a groove,
In order to perform welding of the respective members, an operation command for detecting the protrusion is added to teaching data for a robot created by the offline teaching device for welding according to any one of claims 1 to 4, When reproducing the teaching data with a robot, the three planes of the protrusion are detected by a sensor to correct the teaching data, and welding is performed based on the corrected teaching data. Method.