JPS60124474A - Automatic welding method of circular work - Google Patents

Abstract

PURPOSE:To enable automatic welding even when the centers of the work on a turntable and the turntable deviate by deriving the fluctuation in the data on the servocontrol position of a servocontrol mechanism for the prescribed aiming position of the work as a function of the rotating angle of said table. CONSTITUTION:A work 19 is placed on a turntable 18 while the center of the work 19, i.e., a weld line 20, deviates from the center of the turntable. The rotating angle theta of the table 18 is processed by a servocontrol system and a servocontrol mechanism 14 is so driven as to maintain the specified distance in the Y- axis direction between the torch 15 and the line 20 in the case of performing teaching. The position of the origin of the mechanism 14 at angle theta=0, pi/2, pi, 3pi/2 is processed by the servocontrol system, by which the coordinates at the initial central point P of the line 20 are calculated. The position Y (theta) of the servocontrol origin is derived as the function of the angle theta and is stored. The mechanism 14 is then taught with the intersection point R which is the aiming position and welding is accomplished by reproducing the teaching.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic welding method for circumferentially welding a circular workpiece placed on a turntable.

[Prior art]

Conventionally, when circumferentially welding a large circular workpiece, the circular workpiece is placed on a turntable and moved in the direction of the central axis of the circular workpiece, that is, in the vertical direction, and in the direction of approaching and separating from the circular workpiece, that is, in the front and back direction. A welding head is fixed to a manipulator having a freely movable shaft, and the turntable is rotated to perform circumferential welding of the circular workpiece.

However, in this case, it is very difficult to make the center of the circular workpiece completely coincide with the center of the turntable, and generally the center of the circular workpiece is shifted from the center of the turntable marked 0+J, and the center of the circular workpiece is When the turntable is rotated with the center of the workpiece being eccentric from the center of the turntable, if the welding head is considered as a fixed reference point, the welding head relative to the circular workpiece as seen from the reference point. The predetermined target position of the target position changes, and in order to control the welding head to follow the target position, the manipulator must be moved forward and backward in accordance with the fluctuation of the target position. There are drawbacks.

[Purpose of the invention]

This invention was made with the above points in mind,
By deriving the fluctuation of the servo control position data of the servo mechanism with respect to a predetermined target position of the circular workpiece as a function of the rotation angle of the turntable, it is possible to determine if the center of the circular workpiece is eccentric from the center of the turntable. Even if the servo control position of the servo mechanism is easily derived, the servo mechanism is servo controlled based on the derived servo control position data, and the circular workpiece is automatically welded. do.

[Structure of the invention]

The present invention provides a method for determining the shape of the circular shape when the turntable rotates based on initial position data of the center of the circular workpiece placed on the turntable with respect to the rotation center of the turntable and rotation angle data of the turntable. relative to a predetermined target position on the workpiece. Performing teaching by deriving fluctuations in servo control position data of a servo mechanism mounted on a manipulator as a function of rotation angle, and reproducing the control position data based on the teaching to servo control the servo mechanism;
This automatic welding method for circular workpieces is characterized in that the circular workpieces are welded by a welding torch attached to the servo mechanism.

〔Effect of the invention〕

Therefore, according to the automatic welding method for circular workpieces of the present invention, teaching is performed by deriving the fluctuation of the servo control position data of the servo mechanism with respect to a predetermined target position of the circular workpiece as a function of the rotation angle of the turntable. By regenerating the servo control position data according to Even if the servo mechanism is placed eccentrically on the turntable, it is possible to easily derive the servo control position data of the servo mechanism, and to move the servo mechanism based on the derived servo control position data. It is possible to improve the practicality of QS, which makes it possible to automatically weld the circular workpieces.

[Embodiments] Next, the present invention will be explained in detail with reference to drawings showing embodiments thereof.

In FIGS. 1 and 2 showing automatic welding equipment for carrying out the automatic welding method for circular workpieces of the present invention, (1
) is the base, 12) is the two rails laid on the base (1), (3) is both rails (2) on both rails (2)
' K is a movable trolley, (4) is the main body of the manipulator (5) consisting of two supports (4) etc. fixed to the trolley (3), and (6) is the main body (4). 7 ride beams of a manipulator (5) mounted on the mount so that it can move vertically and longitudinally, (7) are two welding power sources installed on the trolley (3), and (8) are two wire packs. The welding wire (9) is installed on the trolley (3) and is fed to a welding torch (described later).

ao is a servo motor (first servo shaft attached to the front end of the beam (6) so as to be movable in the vertical direction by 1υ;
α Gong is a second servo axis, which is attached to the first servo axis o1 so as to be movable in the front and rear directions by a servo motor. θ insult and both servo motors (]υ
, a servo mechanism 0→ is configured in the awl, and the servo mechanism 0→ is attached to the beam (6) of the manipulator (5).

0υ is made up of two welding torches, which are rotatably attached to the front end of the second servo shaft via a fixture 0. Another 1-chi 0υ is connected to the second servo axis Q through the fixture o0.
A wire (9) is fed from a wire pack (8) using a wire feeder (Iη).

0 frame is a turntable whose rotation angle θ is detected by a rotation angle detector to be described later, and Ql is a turn tape having a circular welding line (A) /I/(a circular workpiece placed on I119, 121) is a control panel, which is installed on the trolley (3), is equipped with push buttons for moving the beam (6) in the vertical and two forward and backward directions, and has a built-in servo control section of a servo mechanism 0Φ.

In addition, FIG. 3 shows the servo control system, and in the same figure, (
(231 is a rotation angle detector consisting of a rotary encoder etc. which detects the rotation angle of the turntable 081 and outputs the angle detection signal.) This is a position detector that detects the origin position of the servo mechanism (14) and sends a position detection signal to the servo control unit @ and the servo mechanism (14) during teaching.
It is designed to be output to the addition point (251) on the input side of the servo, and based on the angle 1 position detection signal, the servo control position data of the servo mechanism 04 is derived by the servo control unit @, and is notated as Derived 1. The servo fIIIlfll signal based on the servo control position data is sent to the servo mechanism (1→
is output to.

Next, from the center of the workpiece (it is difficult to align one center completely with the center of the turntable (181, turntable 08) The center of 1 is heartbroken and work is 0
The operation of the automatic welding apparatus when the material is placed on the turn tape I08) will be explained.

To explain the principle of operation without switching, as shown in Fig. 4, the Y-Z coordinates of the servo mechanism a→, with the moving direction of both servo axes (le, Ill), that is, the front-rear and up-down directions are the Y-axis and z-axis, respectively. With respect to the plane, the X-Y coordinate plane of the servo mechanism 04), which consists of two axes and an X-axis and a Y-axis orthogonal to the Y-axis, can be set as shown in Figure D. Therefore, the welding line (A) can be It can be considered as a circle on the X-Y coordinate plane.

As shown in Fig. 4, if the center O of the turntable α frame coincides with the origin of the X-Y coordinate system, the center of the workpiece 0, that is, the center of the tangent line 1 (a) will be the center of the turntable α frame. Assuming that the turntable (l
As I19 rotates, the middle part of the weld line 11 changes the coordinates of the initial center point P to (εXO
.

εyo), radius AA with origin 0 as middle b; T1
As well as drawing a stone circle S, the servo mechanism 0
As shown in the figure, the aim position of welding line 1a by the tip of
If it is the intersection point with 21, then the turntable Ogl
Due to the rotation of , the coordinates of the intersection point will periodically vary with a certain relationship to the rotation angle of the turntable α frame. It becomes necessary to follow R and move in the Y-axis direction.

In other words, if the initial coordinates of the origin of the servo mechanism σ before rotation of the turntable α frame are (0, yo), then the turntable 0 → rotates by the angle θ and the welding line ((1)
Suppose that the center of is moved from the initial center point P to a point P' on the circle S, then the Y coordinate component of the origin of the servo mechanism aIO (hereinafter referred to as servo origin position) ■θ) is the initial position data. Based on the coordinates of the initial center point P (εXQ, εyo) as a function of said angle θ.

Y(-exa, sinθ+Qo, (Mθ-J(e;
o-L-s1n/II + Qyo-6im θf+'-
r"jxo' E:y.

-εyo+7蓬"17;2-1yO...■, therefore, the coordinates (εxo) of the initial center point P of the welding line 1'4 before the turn tape 7 and 0 rotations.

εyo ) and the rotation angle θ of the turntable 0 are detected, and the X and Y coordinate components εXO, ε of the initial center point P are calculated using the formula
, 0 and the angle θ, it becomes possible to derive the servo origin position Y for the angle θ.

On the other hand, θ-0. By substituting θ−夛, θ−π, and θ−゛, each servo origin position Y(
θ) are respectively Y(0) −y.

Y(N)=txo-εyo+in/2]=;=T-to'
Ten years.

Y(π) knee 2eyo 10)'O y(and 5) = -txo-tyo+J? Knee Cxo”
- to +yQ...■ From the formula ■, both coordinate components εxo of the initial center point P.

Since εyO is expressed as Y(0) = Y(π) 2 °゛■, the distance in the Y-axis direction between the torch 4 and the welding line work is based on the state where the center of the welding line 14 is at the initial center point P. The turntable Q81 is rotated at an angle of 0°2 π, -2- while driving the servo m structure a→ so that the angle is always constant.
The welding line (
The coordinates (εXO, εyo) of the initial center point P in (1) can be calculated.

Based on the above principle, when teaching is performed, the rotation angle θ of the turn tape I and QI19 is detected by the rotation angle detector t23+, and the servo control unit (221
An angle detection signal is output to the servo controller (221), and the rotation angle θ based on the angle detection signal is taken into the servo controller (221). and Y with weld line phrase
Servo mechanism (14) so that the axial distance is constant
The servo motor aυ, (13) is driven and turns π
3π The rotation angle θ of the table (18) is 0. -1π, T, when the servo mechanism (l → I base point position is position detection 8
g (to), respectively, and the servo control unit (22
A position detection signal is output, and the servo control unit Q21 substitutes the Y coordinate component of each position data of the origin of the servo mechanism 0 according to the position detection signal into the above formula (3) and (2) to obtain the welding line (a). Coordinates of the initial center point P (εXO, εyo)
is calculated, and both coordinate components εX of the calculated initial center point P
O.

εyo is substituted as a coefficient into the above equation 0, and the servo control unit @ derives and stores the servo origin position fit Y(θ) as a function of the rotation angle θ of the turn tape I and Q119, and the servo control unit @ derives and stores the servo origin position fit Y(θ) as a function of the rotation angle θ of the turn tape I and Q119. Mechanism (1→ teaching is performed.

Next, when welding is performed by reproducing the teaching data, the servo control unit @ updates the stored servo control position data to the rotation angle detector (23
The servo control signal based on the angle detection signal from the turntable (181) is reproduced every fixed rotation angle, and the servo control signal based on the reproduced servo control position data is transmitted to the servo mechanism a◆
The servo motor 0υ is output to Q3, and the servo mechanism (
The origin of I→ is controlled to a predetermined tracing position with respect to the target position of welding line (4) at the rotation angle θ, the torch (IfJ is controlled to trace), and the torch Q [with] is controlled to be tracing the welding line -4. The workpiece is always held in a fixed position (
1!1 circumferential welding is performed.

Therefore, according to the embodiment, even if the center of the workpiece (11) is eccentric from the center of the turn tape lvu, the servo control position data of the servo mechanism (servo mechanism) can be easily derived, and the derived servo control position data can be easily derived. It is possible to move the servo mechanism a→ based on the data, and it is possible to automatically weld the workpiece 4 placed eccentrically on the turn tape/barrel, which is very practical.

By simply detecting , servo control position data can be derived, and the time required for teaching can be significantly reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the automatic welding method for circular workpieces according to the present invention, FIG. 1 is a perspective view of an apparatus for automatically welding circular workpieces according to the present invention, and FIG. 2 is a part of FIG. 1. 3 is a block diagram of the control system of FIG. 1, and FIG. 4 is an explanatory diagram of the operation of FIG. 1, showing the eccentric state of a circular workpiece with respect to the turntable. (5)...manipulator, (1→...servo am
, a*...Welding torch, (To)...Turntable, (1...Circular workpiece, Agent: Patent attorney Ryutabe Fujita

Claims (1)

[Claims] Based on the initial position of the center of the oval workpiece placed on the turntable with respect to the rotation center of the turn tape I, and the rotation angle data of the turntable, the circular shape when the turntable rotates is determined. relative to a predetermined target position on the workpiece. Fluctuations in the servo control position data of the servo mechanism attached to the manipulator are
Teaching is performed by deriving a function of the rotation angle, the control position take by the teaching is reproduced to servo control the servo mechanism, and the circular workpiece is welded by a welding torch attached to the servo mechanism. An automatic welding method for circular workpieces, which is characterized by: