JPH0366989B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for performing fillet welding by mounting a welding torch on a straight-travel type carriage.

There are various types of conventional profile welding devices, but all of them use the output of a single profile sensor to
Therefore, as the number of elements to be controlled increases, the number of sensors must also increase. Therefore, the structure of the welding device becomes complicated and becomes large.

This invention was made in view of the above-mentioned circumstances, and only one tracing sensor is provided,
It is an object of the present invention to provide a fillet profile welding device in which multiple elements can be controlled by a control device,
Examples will be described in detail below.

W ₁ and W ₂ are workpieces, W ₁ is a horizontal plate,
W ₂ is a vertical board. And the works W ₁ and W ² are
As shown in FIG. 1, they are mutually positioned and tack welded in advance. WL is a weld line formed by both plate materials W ₁ and W ₂ .

Reference numeral 1 denotes a straight-running traveling trolley having four wheels 2, and although details are not shown, it is driven by an electric motor _M1 . E ₁ does not show details, but
This is an encoder for detecting travel distance connected to the wheel 2.

3 is a moving body that is supported by two guide rods 4 fixed to the cart 1 in the left and right direction and moves along the guide rods 4, and is driven by an electric motor _M2 via a known ball screw mechanism 5. be done. Although _E2 is not shown in detail, it is an encoder for detecting the position of the moving body 3.

Reference numeral 6 denotes a mechanism whose base end is vertically supported on the lower part of the movable body 3 and whose distal end rotates in a horizontal plane around an imaginary point Q, and in the embodiment, it is composed of two sets of parallelogram links. It is a parallel link mechanism. The mechanism 6 has links 6a and 6b vertically supported 6c and 6d at the bottom of the movable body 3, and a link 6e with a lever 6f' projecting from the tip of the link 6a, which is connected to the tip of the lever 6f'. A pair of parallelogram links 6g are pivotally supported at the tips of links 6b, and a link 6h is pivoted at the tip of a lever 6a' protruding from the tip of link 6a, and a link 6h is supported between both tips of links 6f and 6h. It consists of a pair of parallelogram links in which a link 6j is pivotally supported 6k and 6l. _M3 is an electric motor that rotates the link 6a around the shaft 6c.
Note that the distal end portion of the mechanism 6, that is, the distal end link 6j 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 6j, and in the embodiment, the vertical surface of the plate material W2 is horizontally supported 7a at the tip of the holding member 6j, and is biased to protrude by a bullet ( _not shown). This is a contact type sensor composed of a tracing roller 7 and a differential transformer TR attached to a holding member 6j to detect the protruding position of the roller 7.

Note that the position of the shaft support 7a of the roller 7 is determined by the distance between the shafts 6c and 6e and the shaft 6k, at the standard protruding position of the roller 7 at the preset standard output value of the sensor S.
7b (rotation center axis of roller 7) are equal,
Furthermore, the distance between the axes 6e and 6k is set to be equal to the distance between the axes 6c and 7b. The torch T is attached to the holding member 6j in such a way that the welding point P of the torch T is below the tip of the roller 7 and on the ground contact surface of the wheel 2 at the reference protruding position of the roller 7. It is set. Then, regardless of the rotation of the link 6a, the torch T rotates in a horizontal plane centering on a virtual point Q, and the torch T
The angle with respect to the weld line WL can be changed. _E3 is an encoder for detecting the angle of the torch T with respect to the welding line WL.

C is a device that controls the electric motors _M1 to _M3 and the welding power source WS, and includes the central processing unit CPU and memory MEM.
It is mainly a computer that includes.
Then, electric motors M ₁ to _{M 3} , drive circuits (drivers) for each of these electric motors MD ₁ to MD ₃ , encoders E ₁ to _{E 3} ,
The sensor S and the power source WS are connected to the control device C via a bus line B as shown in FIG.

The control device C includes a first means A1 for controlling the movement of the movable body 3 so that the output value of the sensor S becomes almost constant based on the output information of the sensor S, and a first means A1 for controlling the movement of the moving body 3 so that the output value of the sensor S becomes almost constant, and a first means A1 for controlling the movement of the moving body ₃ so that the output value of the sensor S becomes almost constant. A second means A ₂ for controlling the rotation of the mechanism 6 so that the rotation is constant.
and a third means _A3 for controlling the traveling speed of the truck 1 so that the welding speed is substantially constant.

The first means _A1 includes means (step _ST2 ) for calculating the difference between the output value from the sensor S and a preset reference value. Also the second means
_A2 includes means (step ST6) for calculating the direction of the straight line _H1 (direction of the welding line WL) passing through both positions from the position information of the positions Pi and Pi+1 of each welding point before a certain time t and _now. ), and means (step ST 8 ) for calculating the torch angle with respect to the direction of the straight line H ₁ (in the embodiment, the torch angle θ with respect to the direction _{H 2 perpendicular} to the straight line H 1 on the ground plane of the trolley ₁ ). It is. Further, the third means _A3 includes means (step _ST6 ) for calculating the direction of a straight line _H1 passing through both positions from the position information of the positions Pi and Pi+1 of each welding point before a certain time t and at the present time. _{Means ( step _}
ST ₁₁ ), and means (step ST ₁₂ ) for calculating the cosine of the angle Ψ and a preset welding speed.

Further, the operation of this embodiment will be explained based on the flowchart of FIG.

First, the operator places the trolley 1 at the position shown in FIG. At this time, the front and back direction of the truck 1 is the welding line WL
The direction is almost the same. Further, it is assumed that the roller 7 is brought into contact with the vertical surface of the plate material _W2 , and the position P of the welding point of the torch T is coincident with one end of the welding line WL.

Then, when the start switch of the control device C is turned on, the power supply WS is turned on. On the other hand, the positional information of the welding point Pi is input into the computer C, with the front-rear direction of the truck 1 as the X-axis and the left-right direction as the Y-axis (step ST ₁ ). Moreover, the forward rotation output of driver MD ₁ is turned ON, and motor M ₁ is driven in forward rotation.
The wheels 2 rotate in the normal direction, and the cart 1 moves forward (upward to the right in FIG. 1) at a preset welding speed, and at the same time, the encoder _E1 starts counting the travel distance.

Then, the output of the sensor S is input to the computer C, the difference from a preset reference value is calculated, and the difference is further converted into the distance in the left-right direction of the truck 1 (step ST ₂ ). Furthermore, the converted value is divided by a certain time t (step ST ₃ ). Note that this fixed time t
is related to the welding speed, which in this example is 0.1
seconds (welding speed 10mm/sec).

And if the said division value is positive, the driver MD ₂
The counterclockwise rotation output of driver MD 2 turns ON, and the motor M ₂ moves the moving body 3 at the speed of the above-mentioned division value (absolute value). Conversely, if the speed is negative, the clockwise rotation output of driver MD ₂ turns ON, and the motor M ₂ , the moving body 3 is moved immersed at a speed equal to the division value (absolute value) (step ST ₄ ).

Therefore, the position P of the welding point of the torch T always coincides with the welding line WL. Furthermore, step ST ₂
~ _ST4 , the first means _A1 is configured to control the movement of the moving body 3 so that the output value of the sensor S becomes approximately constant based on the output information of the sensor S.

When a certain period of time t has elapsed, the current position Pi+1 of the welding point is calculated from the position information of Pi and the outputs of encoders E ₁ and E ₂ , and the position information of Pi+1 is taken into the computer C (step ST ₅ ). Furthermore, the direction of straight line H ₁ passing through Pi and Pi+1 (welding line
(direction of WL) (step ST ₆ ). Furthermore, a direction _H2 perpendicular to the straight line _H1 on the surface of the plate _W1 is calculated (step _ST7 ). Then, the current angle θ of the torch T with respect to the orthogonal direction H ₂ is calculated (step ST ₈ ). Further, the torch angle θ is divided by a certain time t (step ST ₉ ).
If the division value θ/t is positive, the driver
The clockwise rotation output of MD ₃ turns ON, and the torch T is rotated to the right by the electric motor M ₃ at the speed of the above-mentioned division value (absolute value). Conversely, if it is negative, the left rotation output of driver MD ₃ turns ON. , the torch T is rotated to the left at the speed of the division value (absolute value) (step
_ST10 ).

Therefore, even if the welding line WL is a curve, the torch T
The angle with respect to the weld line WL is always approximately constant. Note that steps ST ₁ , ST ₅ to _{ST 10} provide a second means for controlling the rotation of the mechanism 6 so that the angle of the torch T with respect to the welding line WL is approximately constant.
It will be configured as A ₂ .

Next, the angle Ψ of the orthogonal direction H ₂ to the left-right direction H ₃ of the truck 1 is calculated (step
_ST11 ). Furthermore, the welding speed set in advance is
Multiply by cosΨ (step ST ₁₂ ). Furthermore, wheel 2 is driven at the speed of the multiplied value (step
_ST13 ).

Therefore, even if the welding line WL is a curve, the welding speed is always approximately constant. Note that steps ST ₁ and ST ₅
~ _ST7 , _ST11 ~ _ST13 constitute the third means _A3 for controlling the traveling speed of the truck 1 so that the welding speed is substantially constant.

Finally, when the count by the encoder _E1 reaches _K1 , that is, when the trolley 1 travels until the position P of the welding point of the torch T reaches the other end of the welding line WL, the power supply WS is turned off, and the driver _MD1 is turned off. is also turned OFF, truck 1 is stopped,
This means that automatic welding of weld line WL has been completed.

As is clear from the above explanation, in order to keep the output value of sensor S almost constant, and to
The welding line WL can be automatically welded while controlling the respective speeds so that the torch angle relative to the welding speed is approximately constant and the welding speed is approximately constant.

The above description is only an example, and the sensor S may be an optical sensor, an electromagnetic sensor, or a non-contact sensor such as a so-called arc sensor that uses the torch T itself as a tracing sensor. Further, for example, if the welding line WL is substantially straight, the third means _A3 may be omitted. Furthermore, the mechanism 6 is not limited to a parallel link mechanism; for example, the links 6b and 6h are eliminated, and the shafts 6c and 6
A transmission mechanism using a timing belt and a pulley may be provided between e and between the shafts 6e and 6k, respectively. Furthermore, the mechanism 6 at the reference protruding position of the roller 7 at the reference output value of the sensor S,
The holding member 6j may rotate around the tip of the roller 7 instead of around the shaft 7b. It goes without saying that the technical scope of the present invention also includes the replacement of each component with equivalents.

As is clear from the above description, this invention is provided with only one sensor S, but the control device C controls (a) the amount of approach and distance of the torch T to the welding line WL (the amount of movement of the moving body 3), and the amount of welding. In addition to (b) or the above (a), set the torch angle to line WL to the trolley 1.
The running speed of the vehicle can be controlled. That is, even with one sensor S, a plurality of elements can be controlled by the control device C, so there is no need to attach many sensors to the welding device as in the conventional case, and the structure can be simple, lightweight, and compact. In addition, since the mechanism 6 is designed so that the tip 6j rotates around a virtual point (axis 7b in the embodiment), even if the mechanism 6 is rotated to rotate the torch T, the mechanism 6 does not touch the workpiece. There is no joy in conflict.

[Brief explanation of drawings]

Each of the figures shows an embodiment of the present invention.
The figure is an overall perspective view, the second figure is a plan view of the mechanism in which the tip rotates around an imaginary point, and the third figure
4 is a block diagram of the control device, and FIG. 5 is a flowchart for explaining the operation. In the figure, W ₁ ...workpiece (horizontal plate material), W ₂ ...
Workpiece (vertical plate), WL...Welding line, T...Welding torch, P...Position of welding point of torch T, 1...Traveling trolley, 2...Wheels, 3...Moving object, 6...Tip points at a virtual point A mechanism designed to rotate horizontally around the center.
6j... Mechanism tip (torch T holding member), S...
Welding line tracing sensor, 7... Tracing roller, TR...
Differential transformer, C...control device, A1 _... first means for controlling the movement of the moving body 3 so that the output value of the sensor S is approximately constant, _A2 ...welding line of the torch T
A second means for controlling the rotation of the mechanism 6 so that the angle with respect to WL is almost constant, A ₃ ...Third means for controlling the speed of the trolley 1 so that the welding speed is almost constant, ST ₂ ... Sensor Means for calculating the difference between the output value from S and a preset reference value, ST ₆
…Position Pi, Pi of each welding point between a certain time t before and now
From the position information of +1, a straight line H ₁ passing through both positions
ST ₈ ... means for calculating the angle θ of the torch T with respect to the direction of the straight line H ₁ (in the embodiment, the angle of the torch T with respect to the direction H ₂ perpendicular to the straight line H ₁ ), ST ₁₁ ... Means for calculating the angle Ψ of the direction of the straight line H ₁ with respect to the longitudinal direction of the trolley 1 (in the embodiment, the angle in the direction H ₂ orthogonal to the straight line H ₁ with respect to the left-right direction H ₃ of the trolley 1), ST ₁₂ ... cosine of the angle Ψ and a preset welding speed.

Claims (1)

[Claims] 1. A traveling truck, a moving body supported by the traveling truck and movable in the left and right direction of the traveling truck,
a parallel link mechanism whose base end is vertically supported on the movable body and whose distal end is horizontally rotated around an imaginary point; a welding torch holding member integrated with the distal end of the mechanism; It is equipped with a tracing sensor supported by this holding member for detecting the left and right directions of the welding line, and a control device that automatically welds the welding line of the workpiece based on the output of this sensor, and this control device controls the output value of the sensor. a first means for controlling the movement of the movable body so that the distance is approximately constant, and a direction of a straight line passing through the welding points (direction of the welding line) from the positional information of each welding point a certain time ago and the present time is calculated. and further includes a second means for rotating the mechanism so that the angle of the welding torch with respect to the welding line becomes approximately constant by calculating the torch angle with respect to the linear direction. , fillet profile welding equipment.