JPH0418946B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) This invention provides a welding torch and a welding line for a traveling bogie supported by at least three wheels and capable of steering these wheels simultaneously in the same direction and at the same angle. The present invention relates to a fillet profile welding device equipped with a profile sensor.

(Prior Art) Conventionally, there are various fillet profile welding devices equipped with weld line profile sensors. However, these welding devices only match the position of the welding point of the welding torch with the welding line, and when trying to control the angle of the welding torch with respect to the welding line or the speed of the traveling truck, it is a separate matter. A sensor is required for this purpose. Therefore, the structure of the welding device becomes complicated and large, and there are problems in portability.

(Problem to be Solved) This invention was made in view of the above-mentioned circumstances, and it is possible to solve the problem by installing only a welding line tracing sensor that matches the position of the welding point of a welding torch with the welding line. For other control elements,
It is an object of the present invention to provide a fillet profile welding device that is controlled not by a sensor but by a control device.

(Means and effects for solving the problem) The traveling truck has at least three wheels, and these wheels can be simultaneously steered in the same direction and at the same angle by a steering mechanism. A movable body is provided so that it can move horizontally in the left and right directions,
Furthermore, this movable body vertically supports the base end of the parallel link mechanism, and its tip output member is equipped with a welding torch and a welding line tracing sensor, and the tip output member is centered around the tip of the welding torch. It can be rotated horizontally.

Based on the output from the sensor, the position of the moving body is controlled so that the position of the welding point of the welding torch matches the welding line, and the amount of displacement between the current position of the traveling trolley and a position a certain distance before is controlled. Based on the steering angle at the position, the position of the parallel link mechanism is controlled to keep the angle of the welding torch with respect to the welding line constant, and furthermore, the amount of displacement of the movable body from the reference position at both the positions is reduced. One invention is to control the steering mechanism as desired. In addition to this invention, another invention is to control the speed of the traveling cart so as to keep the welding speed constant based on the moving speed of the moving object and a reference speed determined during the position control of the moving object.

(Example) W ₁ and W ₂ are workpieces, W ₁ is a horizontal workpiece, and W ₂ is a vertical workpiece. and both works
W ₁ and W ₂ are mutually positioned and tack welded in advance as shown in FIG. WL is a weld line formed by both workpieces W ₁ and W ₂ .

Reference numeral 1 denotes a traveling trolley (in the embodiment, the planar shape is square), and a total of four wheels 2 (at least three are sufficient) are mounted thereon. All wheels 2
are configured to be driven in the same direction by an electric motor _M1 attached to the bottom of the truck 1 via a power transmission mechanism 3 consisting of a chain 3a, sprockets 3b, 3c, and bevel gears 3d, 3e.
Although _E1 is not shown in detail, it is an encoder for detecting travel distance connected to the wheel 2. S1 is a servo system including an electric motor _M1 and an encoder _E1 .

Reference numeral 4 denotes a steering mechanism, which is configured to be able to simultaneously steer all wheels 2 in the same direction and at the same angle via a chain 4a and sprockets _4b , 4c by an electric motor M2 attached to the bottom of the truck 1.
E ₂ is a steering angle detection encoder of the mechanism 4, although its details are not shown. S2 is a servo system including electric motor _M2 and encoder _E2 .

5 is vertically supported 5a at the upper center of the trolley 1,
It is a rotating body that is rotated by an electric motor _M3 attached to a trolley 1. Although E ₃ is not shown in detail, it is an encoder for detecting the rotation angle of the rotating body 5. S3
is a servo system including electric motor _M3 and encoder _E3 .

6 is supported by the rotating body 5, and is driven by an electric motor _M4 ,
It is a movable body that can be moved in the horizontal direction via a known ball screw type transmission mechanism 7. _E4 is an encoder for detecting the position of the moving body 6. S4 is a servo system including electric motor _M4 and encoder _E4 .

Reference numeral 8 denotes a mechanism which is vertically supported by the lower part of the movable body 6, and whose tip output member is horizontally rotated around the position of the welding point of a welding torch, which will be described later. It is a parallel link mechanism consisting of links. The mechanism 8 includes links 8a and 8b that are vertically supported 8c and 8d at the bottom of the movable body 6, and a link 8 that has a lever 8f' projecting from the tip of the link 8a.
A pair of parallelogram links are formed by connecting the lever 8f' and the link 8b's tip 8g, and a link 8h is connected to the lever 8a' tip protruding from the link 8a's tip. At the same time as arriving at 8i,
It consists of a pair of parallelogram links with links 8k and 8l connected between the ends of links 8f and 8h. _M5 is an electric motor that rotates the link 8a. Note that the distal end output member of the mechanism 8, that is, the distal end link 8j is configured as a holding member for the welding torch T.

S is a welding line tracing sensor supported at the tip of the holding member 8j, and in the embodiment, it is horizontally connected 9a to the tip of the holding member 8j, and is biased to protrude by a bullet (not shown), and detects the vertical surface tracing of the plate material _W2 . roller 9
and an actuating transformer TR that is attached to the holding member 8j and detects the protruding position of the roller 9.

Note that the position of the joint 9a of the roller 9 is determined by the distance between the shafts 8c and 8e and the shaft 8 at the standard protruding position of the roller 9 at the preset standard output value of the detector TR.
The distance between the axes k and 9b (rotation center axis of the roller 9) is equal, and the distance between the axes 8e and 8k is equal to the distance between the axes 8c and 9b.
The distance between the two is set to be equal. In addition, the attachment position of the torch T to the holding member 8j is such that the position P of the welding point of the torch T is on the horizontal plane that is below the tip of the roller 9 and passes through the lower ends of all the wheels 2 at the above-mentioned standard protruding position of the roller 9. is set to. Regardless of the rotation of the ring 8a, the torch T rotates about the shaft 9b, so that the angle of the torch T with respect to the welding line WL can be changed. _E5 is an encoder for detecting the angle of the torch T with respect to the welding line WL. S5 is an electric motor
It is a servo system including _M5 and encoder _E5 .

C is a computer as a control device including a central control device CPU and a memory MEM, and the computer C includes servo systems S1 to S5 and a detector.
TR, welding power source WS is connected to the fourth
Connected as shown.

Then, this control device C compares the output value from the transformer TR with a preset reference value.
A first means for controlling the position of the moving body 6 so that the position P of the welding point of the torch T coincides with the welding line WL
A ₁ + and (b) constant distance l The current displacement of the moving body 6 with respect to the position of the moving body 6 at the position of the cart ₁ one position before.
From YAi and the steering angle α of all wheels 2 with respect to the reference direction (X direction) at the position of the bogie 1 at a certain distance l ₁ before or the current (distance l ₁ before in the example),
Angle θ of welding line WL with respect to the reference direction (X direction)
A second means A ₂ for controlling the position of the mechanism ₈ so as to correct the rotational position of the torch T with respect to the reference direction (X direction) by this angle θ; In the example, the amount of displacement of the moving body 6 with respect to the preset reference position at each position of the trolley 1 between (l ₁ < l ₂ ) and the current value (i.e., YD _i-1 and YD _i )
A third means A ₃ for steering all wheels 2 so that the difference (YD _i −YD _i-1 ) becomes small by comparing
and (d) a fourth means A ₄ for determining the running speed of the truck 1 from the moving speed V ₂ of the moving body 6 and the preset welding speed V ₁ and controlling the truck 1 to this speed.
and are included.

Further, the operation of this embodiment will be explained based on the flowchart of FIGS. 6A and 6B and with reference to FIGS. 5A and 5B.

First, cart 1 is mounted on work W ₁ . At this time, the rotating body 5 is rotated so that the moving direction of the movable body 6 is perpendicular to the line WL to be welded (Y direction).
A rotation position with respect to the trolley 1 is set. Further, the roller 9 is brought into contact with the water surface of the workpiece _W2 , and the position P of the welding point of the torch T is aligned with one end of the welding line WL. Furthermore, all wheels 2 have lines to be welded.
It is directed in the X direction, which is almost parallel to WL. Furthermore, it is assumed that the angle of the torch T around the vertical axis with respect to the X direction is also set to an optimal angle.

Then, when the start switch of the control device C is turned on, the power source WS is turned on, and the cart 1 is driven forward at a preset welding speed _V1 .

Then, the output from the transformer TR is input to the computer C, and the difference between this value and a preset reference value is determined (step ST ₁ ).

Then, it is determined whether the difference is positive or negative, and if it is positive, the moving body 6 is moved inwardly, and if it is negative, it is moved in a protruding manner (step ST ₂ ).

When the difference becomes zero, the moving body 6 is stopped (step ST ₃ ).

Therefore, steps _ST1 to _ST3 compare the output value from the sensor S with a preset reference value and control the position of the moving body 6 so that the position P of the welding point of the torch T matches the welding line. This corresponds to the first means _A1 .

Also, during the position control of the moving body 6, the moving body 6
The moving speed V ₂ of is determined (step ST ₄ ).

Furthermore, √ ₁ ² − ₂ ² is determined, and the speed of the truck 1 is controlled based on this value (step ST ₅ ).

Therefore, steps _ST4 to _ST5 correspond to the fourth means _A4 for controlling the traveling speed of the truck 1 so that the welding speed is constant.

When the trolley 1 travels a certain distance l ₁ (approximately 10 mm), the moving body 6 at the position of the trolley 1 a distance l ₁ in front of the
The current displacement amount YA ₁ of the moving body 6 with respect to the position is determined (step ST ₆ ). In other words, if the distance y _i between the vertical axis 5a and the welding point position P _i is YA _i = (y _i −
y _i-1 ).

Furthermore, the steering angle α of all wheels 2 with respect to the reference direction (X direction) at the position of the truck 1 _one distance l
(Step ST ₇ ).

Furthermore, the amount of displacement YB _i of the moving body 6 corresponding to the angle α is determined (step ST ₈ ). That is, YB _i =
It can be found as l ₁・sinα.

Then, find (YA _i −YB _i ), that is, YC _i .
(Step ST ₉ ). In other words, P _i-1 of the welding point position P _i
The amount of displacement in the Y direction with respect to is calculated.

Furthermore, the rotation angle θ of the torch T corresponding to YC _i is determined (step ST ₁₀ ). That is, θ=
The angle between the position P _i-1 of the welding point and the straight line X direction passing through P _i is determined as tan ⁻¹ YC _i /l ₁ ·cos α.

Then determine whether the angle θ is positive or negative, and if it is positive,
The direction of the straight line H, which is a preset reference torch angle with respect to the
If is negative, the torch T is corrected for rotation by the angle θ to the right with respect to the reference direction of the straight line H (step ST ₁₁ ).

Then, if the rotation of the torch T is corrected by the angle θ,
The mechanism 8 is stopped (step ST ₁₂ ).

That is, from the distances in the X and Y directions from the P _i-1 position to the P _i position, the angle of the welding line WL with respect to the X direction between them is determined, and the angle of the torch T with respect to the H direction is corrected. Therefore, steps ST ₆ to ST ₁₂ correspond to the second means A ₂ for controlling the position of the mechanism 8 so that the angle of the torch T with respect to the weld line WL is approximately constant even if the weld line WL is a curve. It turns out.

Furthermore, when the trolley 1 travels a certain distance l ₂ (approximately 60 mm in the embodiment with l ₁ < l ₂ ), the preset reference position of the moving body 6 (Y between the vertical axis 5a and the welding point position)
The current displacement YD _i of the moving body 6 with respect to the position whose directional distance is y _p is determined (step ST ₁₃ ).

Furthermore, the current displacement YD _i and the distance l ₂ Carriage 1 in front
The amount of displacement YD _i-1 of the movable body 6 with respect to the reference position of the movable body 6 at the position is compared (step
_ST14 ).

And the sign (positive or negative) of the displacement YD _i is
It is determined whether the sign of YD _i-1 has changed, and if the sign has changed, the steering angles of all wheels 2 relative to the reference direction (X direction) are controlled to zero degrees (step ST ₁₅ ). .

In addition, if the sign does not change, the amount of displacement
It is determined whether YD _i and YD _i-1 are both positive or both negative (step ST ₁₆ ).

And if YD _i and YD _i-1 are both positive, YD _i ≧
Determine whether YD _i-1 , and if YD _i ≧YD _i-1 ,
All the wheels ₂ move further to the left by a certain angle (for example, 5
degree) is steered (step ST ₁₇ ).

Conversely, if YD _i and YD _i-1 are both negative, YD _i
Determine whether ≦YD _i-1 , and if YD _i ≦YD _i-1 ,
All wheels ₂ move further to the right by a certain angle (for example, 5
degree) is steered (step ST ₁₈ ).

In other words, the movable body 6 is not largely displaced from the predetermined reference position, and the steering angle of all wheels 2 is not frequently changed to the left or right with respect to the reference direction (X direction). Dolly 1 is a welding line
The steering control is designed to follow a path similar to WL. Therefore steps ST ₁₃ to _{ST 18}
However, in order to reduce the difference between YD _i and YD _i-1 , all wheels 2
This corresponds to the third means _A3 that was intended to steer the government.

When the trolley 1 completes traveling from the welding start point to the welding end point, the power supply WS is turned off.
Truck 1 is also stopped.

As described above, the means A ₁ controls the position of the moving body 6, the means A ₂ controls the position of the torch T, the means A ₃ controls the steering of all the wheels 2,
Furthermore, the welding line WL is automatically welded while controlling the traveling speed of the truck 1 by means _A4 .

In the above-mentioned embodiment, the rotating body 5 is rotatably vertically supported on the traveling trolley 1, and the movable body 6 is horizontally movably supported on this rotating body. Even when the workpiece W ₂ is formed into a U-shape or the like and the welding line is bent at a right angle, the rotational position of the rotating body 5, the forward/backward movement of the traveling trolley 1, and the steering angle can be suitably executed sequentially. Therefore, the rotating body 5 is not an essential part of the present invention, since the operator does not have to reset the traveling carriage 1 at a bending point. That is, the moving body 6 may be directly supported by the traveling carriage 1. In addition to a contact sensor, the sensor S may be a non-contact sensor such as an optical sensor, an electromagnetic sensor, an ultrasonic sensor, or a so-called arc sensor using the torch T itself as a pattern sensor. It goes without saying that the technical scope of the present invention also includes the replacement of each component with equivalents.

(Effects) As mentioned above, this invention can be used as a sensor.
Only the welding line tracing sensor is provided to match the welding point position P of the torch T with the welding line WL, and other elements to be controlled are the angle of the torch T with respect to the welding line WL, the steering angle of all wheels 2, Alternatively, regarding the running speed of the truck 1, the control device C
As a result, the welding device has a simple structure, small size, and light weight, and is highly effective.

[Brief explanation of drawings]

The figures all show embodiments of the present invention, with Fig. 1 being an overall perspective view, Fig. 2 being a bottom view of the traveling trolley, and Fig. 3 being a bottom view of the traveling trolley.
The figure is a plan view of the welding torch and weld line tracing sensor, Figure 4 is a block diagram of the control device, and Figure 5 is a block diagram of the control device.
Figures A and B are action explanatory diagrams, and Figures A and B are flowcharts. In the figure, W ₁ ... horizontal workpiece, W ₂ ... vertical workpiece, WL ... welding line, T ... welding torch,
P...Position of welding point of torch T, 1...Traveling trolley, 2...Wheels, 4...Steering mechanism, 6...Moving body, 8...Parallel link mechanism, 8c, 8d...Axles, respectively. 8j... Tip output member of mechanism 8 (torch holding member), S... Welding line tracing sensor, C...
...control device, _A1 ...first means, _A2 ...second means,
A ₃ ... the third means, A ₄ ... the fourth means.

Claims (1)

[Claims] 1. A traveling truck supported by at least three wheels and capable of steering these wheels simultaneously in the same direction and at the same angle; and a traveling truck supported by the traveling truck and capable of horizontal movement in left and right directions with respect to the welding line. a moving body, and a parallel link mechanism which is vertically supported by the moving body, and whose tip output member holds a welding torch and a welding line tracing sensor, and which is horizontally rotated about the tip of the welding torch. , and a control device into which the output from the welding line tracing sensor is input, and the control device (a) compares the output value from the sensor with a preset reference value to control the welding of the welding torch. (b) a first means for controlling the position of the movable body so that the position of the point coincides with the welding line; The angle of the welding line with respect to the reference direction is determined from the position and the steering angle of all the wheels with respect to the reference direction at the certain distance before or at the current position of the traveling vehicle, and the angle of the welding line with respect to the reference direction is determined by this angle. (c) a second means for controlling the position of the link mechanism so that the angle of the welding torch with respect to the welding line is substantially constant by correcting the rotational position with respect to the reference direction; and third means for comparing the amount of displacement of the movable body at each position of the traveling bogie with respect to a preset reference position, and steering all the wheels so that the difference is small. A fillet profile welding device. 2. The fillet profile welding device according to claim 1, wherein the weld line profile sensor is a contact type sensor. 3. The fillet profile welding device according to claim 1, wherein the weld line profile sensor is a non-contact type sensor. 4. A traveling truck supported by at least three wheels and capable of steering these wheels simultaneously in the same direction and at the same angle; a moving body supported by the traveling truck and capable of horizontal movement in the left and right directions with respect to the welding line; a parallel link mechanism that is vertically supported on a movable body and whose tip output member holds a welding torch and a welding line tracing sensor, and is horizontally rotated about the tip of the welding torch; and the welding line tracing sensor. (b) Compares the output value from the sensor with a preset reference value, and determines whether the welding point of the welding torch is at the welding line. (b) a current displacement position of the moving body with respect to the position of the moving body at the position of the traveling trolley a certain distance before the moving body; The angle of the welding line with respect to the reference direction is determined from the steering angle of all the wheels with respect to the reference direction at the front or current position of the traveling truck, and the welding torch is rotated with respect to the reference direction by this angle. (c) a second means for controlling the position of the link mechanism by correcting the position so that the angle of the welding torch with respect to the welding line is substantially constant; a third means for comparing the amount of displacement of the movable body at each position with respect to a preset reference position and steering all the wheels so that the difference is small; (d) the moving speed of the movable body; and a fourth means for determining the traveling speed of the traveling truck from the preset welding speed and the welding speed, and controlling the traveling truck to this speed to keep the welding speed constant. Welding equipment.