JPH07102463B2 - Multi-layer welding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-layer welding method using a welding robot.

[Conventional Technology] Instead of the conventional welding work that relies on the experience and intuition of workers,
Welding robots have been popularized for the purpose of saving labor, improving quality, and improving environmental conditions such as welding work. Among welding operations performed by a welding robot, multi-layer welding is a very important operation for securing the strength of the welded portion, but it is technically difficult in many cases.

In Japanese Patent Laid-Open No. 57-50279, a welding robot capable of calculating the welding torch tip position from predetermined constants and variables and controlling the welding torch tip to follow a desired locus sequentially presets desired constants. There is described a multi-layer welding method capable of performing multi-layer welding by changing the amount and moving the tip of the welding torch from a desired locus by the preset amount.

[Problems to be Solved by the Invention]

However, due to welding work, it may be required to change the posture of the torch 3 from the first layer to the second layer and the third layer in order as shown in FIG. In such a case, the above-mentioned multi-layer welding method only calculates the position and does not take into consideration changing the attitude of the torch. Therefore, if the attitude of the torch needs to be changed, the correction must be made by sequentially teaching the second layer and the third layer, which requires a great deal of work.

The present invention has been made in view of such circumstances, and an object thereof is to automatically calculate the torch posture and perform multi-layer welding.

[Means for Solving the Problems]

In order to achieve this object, the multi-layer welding method of the present invention,
In a multi-layer welding method using a teaching playback robot capable of scaling calculation, the torch motion locus in the welding of the first layer is stored, and the torch rotation angle is externally given as a parameter, and the motion loci of the second and subsequent layers are stored. After obtaining, the torch is rotated by the torch rotation angle around the advancing direction vector obtained at the teaching point, the posture data is calculated and obtained, and welding of the second and subsequent layers is performed based on the obtained posture data. Characterize.

[Action]

In the present invention, the torch position data in the welding of the first layer is taught, and the torch rotation angles of the second and subsequent layers are given as parameters in advance. The movement locus of the first layer during welding is obtained from the teaching data, and the movement loci of the second and subsequent layers are obtained by giving a predetermined shift amount to the teaching locus or the movement locus of the first layer. At this time, the torch is rotated by the torch rotation angle given as a parameter in advance, and welding is performed in a predetermined torch posture.

〔Example〕

 Hereinafter, the present invention will be specifically described based on Examples.

FIG. 1 is a block diagram showing a configuration of a robot control unit for carrying out the present invention.

In FIG. 1, reference numeral 1 is a robot controller, which is a position data storage unit 11 for storing the taught first layer position data,
A scaling calculation unit 12 that calculates each point of the motion locus of each layer and a storage unit 13 that stores the position data after scaling are provided.

FIG. 2 shows an operation procedure in the posture rotation angle storage unit 14 and the posture change calculation unit 15. That is, the rotation angle storage unit 14 stores the set rotation angles (α _{1 to} α _N ) of the torch postures from the first layer to the Nth layer (steps 20 and 21 in FIG. 2). Next, in the posture change calculation unit 15, the welding line between the welding start point P _N and the end point P _{N + 1} (see FIG. 3 (a), 2 in the figure is a workpiece, 3 is a torch). Is calculated (step 22 in FIG. 2).

Specifically, the following calculation is performed.

If the direction cosine of is K _x , K _y , K _z , this direction cosine can be obtained as follows.

K _x : X component K _y : Y component K _z : Z component K _x : ΔX / LK _y : ΔY / LK _z : ΔZ / L Next, the posture change calculation unit 16 determines the posture of P _N as shown in step 23 of FIG. 2 and FIG. 3 (b). A calculation of rotating α (α _{1 to} α _N ) around is performed.

Specifically, the following calculation is performed.

The posture of the robot at the position P _N is Can be represented by a matrix of 3 rows and 3 columns.

Next, the rotation of the arbitrary vector () (general rotation transformation) is
Let sinα be sα, cosα, and (1-cosα) be vα, Can be expressed as

Therefore, if the desired posture is T ', then T' = Rot
It can be calculated from (K, α) · T.

The above processing is performed until N reaches the total number of points (second
Steps 24, 25 in the figure).

The robot interpolation calculation unit 16 in FIG. 1 performs a predetermined interpolation calculation and outputs it as a motion command to the robot.

〔The invention's effect〕

As described above, according to the present invention, in the multi-layer welding method, after the motion locus of the first layer is stored and the torch rotation angle is externally given as a parameter, the motion loci of the second and subsequent layers are obtained. Since the torch is rotated by the torch rotation angle around the advancing direction vector obtained at the teaching point and the posture data is calculated, the posture conversion of multi-layer welding can be automated simply by inputting the torch rotation angle. The operation of the operator becomes extremely easy.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a robot control unit for carrying out the present invention, FIG. 2 is a flowchart showing its operating procedure, and FIG. 3 is an explanation of the rotating operation of a welding torch according to the present invention. FIG. 4 and FIG. 4 are explanatory views of multi-pass welding. 1: Control device 2: Work 3: Torch 11: Position data storage unit 12: Scaling calculation unit 13: Position data storage unit 14: Posture rotation angle storage unit 15: Posture change calculation unit 16: Robot interpolation calculation unit

Claims (1)

[Claims] 1. A multi-layer welding method using a teaching playback robot capable of scaling calculation, comprising:
The movement trajectory of the torch in the welding of the first layer is stored, and the torch rotation angle is externally given as a parameter.
After obtaining the motion loci of the second and subsequent layers, the torch is rotated by the torch rotation angle around the advancing direction vector obtained at the teaching point, the posture data is calculated, and the two layers are calculated based on the obtained posture data. A multi-layer welding method characterized by performing welding after the eyes.