JPS58173084A - Copy welding device - Google Patents

Abstract

PURPOSE:To perform copy welding while controlling the attitude of a torch with respect to a weld line easily, by mounting a torch holding member and a sensor for copying a weld line to the output member at the tip of a robot, and controlling the positions of the output member and the holding member respectively. CONSTITUTION:A torch holding member 7 for welding and sensors SE1, SE2 for copying a weld line are mounted to the link-like output member 6c at the tip of a robot which is positioned at >=2 dimensions. The member 7 is moved to make the position of a torch T coincident with the start point P1 for welding, and the angle around an axis alpha with respect to a weld line WL is adjusted. The torch T is then moved under linear interpolation control. The outputs from the sensors SE1, SE2 are compared with a reference value during this time and the member 6c is operated to control the position of the torch T so as to copy the line WL. The angle of the torch T is also controlled so as to be made constant with respect to the line WL, whereby the copy welding is accomplished automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus that automatically traces and welds fillet and butt weld lines by attaching a welding torch to a robot that is positioned in at least two dimensions.

Conventionally, there are various tracing welding devices equipped with welding line tracing sensors. However, these welding devices simply follow the welding line, and if the attitude of the welding torch with respect to the tangent to the welding strip is also controlled, a separate sensor is required.

Therefore, the structure of the welding device becomes complicated.

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 profile welding device in which only a welding line tracing sensor is provided as a sensor, and the attitude of a welding torch with respect to the welding line can be controlled by a control device. and
The embodiment will be described in detail below. First, the embodiment shown in FIGS. 1 to 4, that is, the profile welding apparatus for the fillet weld line will be described in detail.

w and W2 are workpieces, Wl is a horizontal workpiece, and W2 is a vertical workpiece. WL is both work w,
, is the fillet weld line formed by w2.

1 is a fixed guide in the X direction.

2 is a moving body supported by the guide 1 and movable in the X direction.

3 is a horizontal arm supported by the moving body 2 and movable in the Y direction.

A vertical arm 4 is supported at the tip of the arm 3 and is movable in the Z direction.

Reference numeral 5 denotes a rotating body that is vertically supported 5a at the lower end of the arm 4 and is rotatable in the α direction.

Reference numeral 6 denotes a parallel link mechanism which is horizontally supported 6a and 6b at the lower end of the rotating body 5 and rotates in the β direction, and whose stock end link 6C rotates in a vertical plane around a virtual point. This is means for changing the elevation angle of a welding torch, which will be described later.

The three-dimensional positioning robot robot (R) of this embodiment is configured by the above 1 to 6, and is formed as a welding robot with 5 degrees of freedom in a rectangular coordinate system. In addition, the stock end link 6C of the change means 6
corresponds to the tip output member of Roboso)R.

7 is a holding member for the welding torch T attached to the link 6C. P is the position of the welding point of the torch T, P] is the position of the welding start point, and P. indicates the position of the welding end point.

S El + S E2 are welding line tracing sensors attached to the holding member 7, and in the example, each workpiece w
1. A non-contact sensor (e.g. optical plane) on the surface of w2.
5 wedding ceremony, electromagnetic type, ultrasonic type sensors, etc.).

C is a control device, which is mainly a computer including a central processing unit CPU and a memory MEM. As shown in Fig. 3, the computer C includes a remote control panel RE, a welding power source WS, an X-axis servo system sx, a y-axis servo system sy, a z-axis servo system Sz1 and an α-axis servo system S.
A servo system Sβ for the α and β axes, and sensors SE, , SE2 are connected via a path line B.

Note that the control device C is configured to connect the tip output member of the robot)H, that is, the link 6c, to the welding line WL (workpieces wl, w) so that the output value from the sensors SE and SE2 is almost constant.
The holding member 7 is controlled in position so that the angle of the torch T with respect to the welding line WL (the angle of the α-axis notch) is approximately constant. This includes a second means A2 which is designed to be used as a base station, and a known linear interpolation control means (not shown).

The first means A1 includes means for calculating the difference between each output value from the sensors SEI and SE2 and a preset reference value (steps ST17+ST2 to be described later).

In addition, the second means A2 includes means (
Step 5T7) to be described later, means for calculating the current angle of the torch T around the α axis with respect to the straight line H1 (in the embodiment, the angle θ1 of the torch T with respect to the Y-axis direction) (step S Too to be described later); Angle θ of torch T]
and the angle of the torch T around the α-axis with respect to the preset welding line WL (in the embodiment, the preset torch angle θ2 with respect to the Y-axis direction), that is, (θ1-θ2), is calculated, and dθ is obtained ( Step S T11) to be described later
and are included.

Further, the operation of this embodiment will be explained. 0. Don't hesitate to operate the remote control panel RE to store the welding start point position P1 and the welding end point position P8 in the computer C (step 5T1). Holding member 7
Move the torch T to the position shown in the figure, align the welding point position of the torch T with Pl, and α
The angle 7 around the axis is the optimal angle (in the example, the angle with respect to the Y-axis direction is θ2)
Adjustment is made in advance so that (step ST2).

Then, when the start switch (not shown) on the remote control panel RE is turned on, the torch T is moved from the P1 position to the P8 position at a preset welding speed (for example, 10 mm/sec) while being controlled by linear interpolation (step 5T3). ), and the welding power source WS is also turned on (step 5T4).

When a certain period of time t (for example, 01 seconds) has elapsed (step 5T5), the current welding point position PH-+ (i is the number of times this step ST60 has been passed) is loaded into the computer C (step 5T6).

Next, a straight line H1 passing through the previous P1 position and the current Pi position for a certain period of time is calculated (step 5T7).

Further, on the straight line HJ, the next target position P1+2 after a predetermined predetermined time has elapsed from the current welding speed is calculated (step 5T8).

Furthermore, a straight line H2 corresponding to a preset α-axis switching torch angle with respect to the straight line H1 is calculated (step 5T).
9).

Furthermore, the angle θ2 of the twisted straight line H2 with respect to the Y-axis direction and the current angle θ1 of the torch T with respect to the Y-axis direction are calculated (step 5no).

Furthermore, (θ1-θ2) is calculated and its value dθ is obtained (step ST], 1.).

Then, it is determined whether dθ is positive or negative, and if it is positive, the torch T is rotated to the left, and if it is negative, it is rotated to the right, respectively, at the trench where dθ becomes zero (Steps ST]2 to ST14). Through steps S T7 and S T9 to S T14 described above, even if the weld line WL is a curve, the position of the holding member gourd is controlled so that the angle around the α axis of the torch T with respect to the weld line WL is almost constant. It is configured as second means A2.

When dθ becomes zero in step ST]4, the torch T is moved from the position Pi+ toward the target position Pi+2 (step ST]5).

In addition, at this time, the first above-mentioned P1 position and P. The linear interpolation control between the positions is terminated, and instead the linear interpolation control between the positions Pi and Pi+2
Linear interpolation control between the positions is executed.

Next, in step S T5, after a certain period of time has elapsed, the
9, and after step ST]5, the output value from the sensor SEl is taken into the computer C (step ST]6).

Then, the difference between the output value and a preset reference value is calculated (step 5TI7).

Then, it is determined whether the difference is positive or negative, and if it is positive, the torch T is moved in the direction away from the workpiece W1, and if it is negative, it is moved in the direction of approach, respectively, by 1 where the difference becomes zero (step S T18~STh+).

Further, the output value from the sensor SE2 is taken into the computer C (step ST2]).

Then, the difference between the output value and a preset reference value is calculated (step 5T22).

Then, it is determined whether the difference is positive or negative, and if it is positive, the torch T is moved in the direction away from the workpiece W2, and if it is negative, it is moved in the direction of the approach, until the difference becomes zero (step ST23-5T25).

Note that in steps ST]6 to ST25, the sensor SE1. The second means A2 is configured to control the position of the tip output member of the Roboso l-R, that is, the link 6c, with respect to the welding head 10aWL so that the output value from the SE2 is substantially constant.

When the difference in step ST25 becomes zero, the value of 1 is updated by one (step 5T26), and P1'P in steps ST6 to STs and 5T15 is updated by one (step 5T26).
t-1-+i Pl]-2 will be updated by one.

Then, it is determined whether the Pi position matches the P8 position which is the welding end point, and if it does not match, the step S
The steps T5 to 5T270 are repeated, and when they match, the welding power source WS is turned off, and the movement of l·-chi T is also stopped (steps ST27 to 5T28).

As described above, the position of the torch T is controlled to follow the welding line WL based on the output information from the sensors SEI and SE2, and the angle of the torch T with respect to the welding line WL is also kept almost constant by the second means A2. The welding line WL is automatically welded from the P1 position to the Pe position.

The speed control in each axis direction of the robot R to keep the welding speed constant will not be described in detail, but... Since this is performed by linear interpolation control between the Pi position and the P1+2 position, which are recorded every time, the welding speed is maintained constant even if the welding line WL is a curve.

Next, in the embodiment shown in FIG. 5, both works w3. Regarding the case of tracing and welding the butt weld line WL of w4, the differences from the previous embodiment will be explained in particular.

In this case, the first means A1 includes the sensor SEA.

S F2 is removed and a sensor is installed in its place, for example, at a position preceding the torch T, and based on the output information from the sensor, the link 6c is installed in order to match the position of the welding point of the torch T with the welding line WL. will be position controlled. In addition, in the second means A2, the above-mentioned step S
T9 is replaced with a step of calculating a straight line H3 corresponding to the elevation angle of the torch T set in advance with respect to the straight line H1, and the aforementioned step STIO calculates the current elevation angle of the torch T (Y in the embodiment) with respect to the straight line H1. The above-mentioned step ST]] is replaced with a means for calculating the angle γ1) of the torch T with respect to the axial direction, and the step ST]] is calculated by calculating the current angle F] of the torch T and the elevation angle (Y in the embodiment) of the torch T with respect to the preset welding line WL. Calculate the difference between the preset torch angle with respect to the axial direction, that is, the angle F2) of the straight line H3 with respect to the Y-axis direction, that is, (Fl-F2), and calculate the value d1. Each step is replaced with a step of rotating until it becomes zero.

Other configurations and operations can be explained in accordance with the previous embodiments, so their explanations will be omitted.

The above explanations are all examples, and the sensor SE1゜S
F2 may be a contact type sensor in which a roller is biased to protrude, for example, modeled on a differential transformer, or may be a so-called arc sensor in which the torch T itself is used as a sensor. Furthermore, the robot) R may be of a multi-joint coordinate system, a cylindrical coordinate system, or a polar coordinate system, or may be a two-dimensional positioning robot.

It goes without saying that the technical scope of the present invention also includes the replacement of each component with equivalents.

I B As described above, this invention uses a torch T as a sensor.
Although the welding line tracing sensor S El, S E2L is not attached to the holding device 7 to match the position of the welding point with the welding line WL, the posture of the torch T with respect to the welding line WL is almost constant by the second means A2. The position can be controlled so that

That is, only one type of sensor is required, and the structure of the welding device, especially the robot R, is simplified.

[Brief explanation of drawings]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is an overall schematic explanatory diagram, FIG. 2 is an explanatory diagram of the operation, FIG. 3 is a block diagram of the control system, and FIGS. B) is a flowchart. FIG. 5 is an explanatory diagram showing another embodiment of the present invention. In the figure, W1 to W4...Workpiece, WL...Corner welding line, WL...Butt welding line, T...Welding torch, R...Three-dimensional positioning robot), 6c=Robot)
H tip output member (in the embodiment, the stock end link of the elevation angle changing means 6), 7... Torch holding device, P... Welding point position, C... Control device, S El r S F2.
・・Respectively Ivy 14 Welding line tracing sensor, AI・・Sensor SE1. sE2
A first means for controlling the position of the tip output member 6c of the robot) R with respect to the welding lines WL, WL so that the output value of the torch is approximately constant; A second means for controlling the position of the holding member 7 so that its posture is almost constant, S
Means for calculating 1, STIO... Straight line H. Means for calculating the current angle of the torch T (in the embodiment, the angle θ1 with respect to the Y-axis direction or the angle F1 with respect to the Y-axis direction), S T11...The current angle of the torch T and the preset welding lines WL, WL means for calculating the difference between the angle of the torch T (in the embodiment, the angle θ2 with respect to the Y-axis direction or the angle F2 with respect to the Y-axis direction), 5T17.
...Means for calculating the difference between the output value from the sensor S El and a preset reference value, S T22...Sensor S F2
means for calculating the difference between the output value from the controller and a preset reference value. Applicant ShinMaywa Industries Co., Ltd. Agent Tadashi Bengami (1 other person)

Claims (5)

[Claims] (1) A welding torch holding member and a welding line tracing sensor attached to the tip output member of a robot that is positioned in at least two dimensions, and a control device to which the output from the welding line tracing sensor is input; The control device includes a first means for controlling the position of the tip output member of the robot with respect to the welding line so that the output value from the welding line tracing sensor remains approximately constant; The angle of the torch is approximately constant.
- second means for controlling the position of the tip holding member. (2) The profile welding apparatus according to claim 1, wherein the first means includes means for calculating a difference between the output value from the weld line profile sensor and a preset reference value. (3) the second means is a means for calculating a straight line passing through the position of the point of contact between two images from a certain time ago and the present; and a means for calculating a current angle of the welding torch with respect to the straight line;
2. The profile welding apparatus according to claim 1, further comprising means for calculating a difference between the current welding torch angle and a preset angle of the welding torch with respect to the welding line. (4) The profile welding apparatus according to claim 1, wherein the weld line profile sensor is a contact type profile sensor. (5) The profile welding apparatus according to claim 1, wherein the weld line profile sensor is a non-contact type profile sensor.