JPH0333435B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for performing fillet welding by mounting a welding torch on a traveling truck whose wheels can be steered.

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. 4, they are mutually positioned and tack welded in advance. WL (WL ₁ to WL ₃ ) are weld lines formed by both plate materials W ₁ and W ₂ , respectively.

Reference numeral 1 denotes a traveling trolley (having a square planar shape in the embodiment), on which a total of four wheels 2 are mounted.
All wheels 2 are powered by electric motors attached to the bottom of the trolley 1.
M ₁ connects chain 3a and sprocket 3
b, 3c and bevel gears 3d, 3e to be driven in the same direction via a power transmission mechanism 3. E ₁ does not show details, but
This is an encoder for detecting travel distance connected to the wheel 2.

Reference numeral 4 denotes a steering mechanism, which is configured to be able to simultaneously steer all wheels 2 in the same direction 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.

5 is vertically supported 5a at the upper center of the trolley 1,
This is a rotating body that is rotated by an electric motor _M3 (not shown). Although E ₃ is not shown in detail, the rotating body 5
This is an encoder for detecting rotation angle.

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.

8 horizontally attaches one end to the tip of the moving body 6 8a
It is a rotating member.

Reference numeral 9 denotes a mechanism that is vertically supported on the lower part of the member 8 in a horizontal state, and whose tip part rotates horizontally around an imaginary point (an axis 10b to be described later in the example). It is a parallel link mechanism consisting of quadrilateral links. In the mechanism 9, when the member 8 is in a horizontal state, links 9a and 9b are vertically supported 9c and 9d at the lower part of the member 8, and a link 9f with a lever 9f' projecting from the tip of the link 9a is connected 9e.
Then, a pair of parallelogram links are formed by joining the tip of the lever 9f' and the tip of the link 9b 9g, and a link 9h is connected 9i to the tip of the lever 9a' protruding from the tip of the link 9a, and the link 9f A pair of parallelogram links 9k and 9l are connected between the ends of 9h and 9j. _M5 is
This is an electric motor that rotates the link 9a around the shaft 9c. Note that the tip link 9j of the mechanism 9 is configured as a holding member for the welding torch T.

S ₁ is a welding line tracing sensor supported at the tip of the holding member 9j, and in the embodiment, the plate material W ₂ is horizontally attached to the tip of the holding member 9j and urged to protrude by a bullet (not shown). The surface tracing roller 10 is attached to the holding member 9j, and the roller 10
This is a contact type sensor consisting of a differential transformer TR that detects the protruding position of the

11 is the lower part of the holding member 9j (on the same axis as the shaft 9k)
This is a free roller attached to the top surface of plate material _W1 .

Note that the position of the joint 10a of the roller 10 is such that the distance between the shafts 9c and 9e is equal to _the distance between the shafts 9k and 10b at the reference protruding position of the roller 10 at the preset reference output value of the sensor S1, and the distance between the shafts 9e,
The distance between the axes 9k and the distance between the axes 9c and 10b is set to be equal. Further, the attachment position of the torch T to the holding member 9j is the position P of the welding point of the torch T.
is set to coincide with a horizontal plane passing below the tip of the roller 10 and passing through the lower end of the roller 11 at the reference protruding position of the roller 10 . Regardless of the rotation of the link 9a, the torch T rotates horizontally about the shaft 10b, and 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.

S ₂ is a plate material W ₂ with a total of 4 protruding pieces on each side of the trolley 1.
Detector (e.g. limit switch).

In other words, the detector S ₂ detects the vertical workpiece, that is, the side wall of the plate material W ₂ that is an obstacle to the traveling of the trolley 1, and
This is for outputting a stop signal to at least the truck 1.

C is a device that controls the electric motors _M1 to _M5 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 5} , drive circuits (drivers) for each of these electric motors MD ₁ to MD ₅ , encoders E ₁ to _{E 5} ,
Sensor S ₁ , detector S ₂ and power source WS are connected to control device C via bus line B as shown in FIG.

The control device C includes a first _means A1 for controlling the movement of the movable body 6 so that the output value of the sensor _S1 is almost constant based on the output information of the sensor _S1 , and an angle of the torch T with respect to the welding line WL. a second means _A2 for controlling the rotation of the mechanism 9 so that the
A third means A 3 for controlling the speed of the truck 1 so that the welding speed is constant; and a fourth means A ₃ for controlling the steering of all wheels 2 so that the distance between the welding line WL and the truck 1 is approximately constant. Means A ₄ is included.

Specifically, the first means _A1 calculates the difference between the output value from the sensor _S1 and a preset reference value (step ST2), and moves the moving body 6 so that the difference becomes approximately constant. It is something to control. Also the second means
A ₂ is the position of each welding point before a certain time t and now.
From the position information of Pi and Pi+1, calculate the direction of a straight line passing through these positions (direction of welding line WL) (step ST5), and also calculate the torch angle with respect to the straight line direction (in the example, the direction of the straight line on _one side of the plate material W). is an angle with respect to the orthogonal line) (step ST6), and the mechanism 9 is controlled to rotate so that the angle of the torch T with respect to the welding line WL is approximately constant. Further, the third means _A3 calculates the position Pi+2 of the next virtual welding point that will be reached after a certain period of time t has passed on the straight line obtained in step ST5 (step ST8), and calculates the position Pi+2 of the next virtual welding point that will be reached after a certain period of time t has elapsed (step ST8), The speed is controlled so that the traveling speed (welding speed) of No. 1 is approximately constant. In this embodiment, after step ST8, from the Pi+2 position to the current moving direction of the moving body 6 (left and right direction of the truck 1) and the truck 1
A certain distance L2 to the side (the position of the welding point of the torch T at the preset reference position of the moving body 6 and the vertical axis 5a)
virtual position of the next vertical axis 5a separated by
While calculating Oi+2 (step ST9),
That position Oi+2 and the current position Oi+ of the vertical axis 5a
The traveling speed of the truck 1 is calculated by calculating the distance l from the truck 1 and further dividing the distance l by a certain time t (step ST10). Furthermore, the fourth means _A4 is performed at both positions Pi+1 after step ST8.
In addition to calculating the direction of a straight line passing through and Pi+2, the angle of that straight line with respect to the current steering direction of all wheels 2 is calculated, and the steering direction is calculated to keep the distance from the welding line WL of bogie 1 approximately constant. control. In this embodiment, after step ST9, the direction of a straight line passing through the two positions Oi+2 and Oi+1 is calculated, and the angle φ of the straight line with respect to the current steering direction of all wheels 2 is calculated (step ST12).
By this, the steering angle is determined.

Further, the operation of this embodiment will be explained based on the flowcharts of FIGS. 9A and 9B and FIG. 10.

First, the operator places the trolley 1 at the position shown by the solid line in FIG. At this time, the rotation body 5 is set at a rotation angle such that the moving direction of the movable body 6 is perpendicular to the direction in which the trolley 1 is desired to move (vertical direction in FIG. 4). Further, the roller 10 is in contact with the vertical surface of the plate material _W2 . Furthermore, the roller 11 is made of a plate material.
A member 8 that is in contact with the upper surface of W ₁ and whose center is the shaft 8a
Rotation is restricted by gravity. For convenience of explanation, it is assumed that the mechanism 4 is steered at an angle in which all wheels 2 are directed upward in FIG.

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 shaft 5a
With Oi as the origin and the steering direction of all wheels 2 as the Xi axis, the positional information of the welding point Pi is input into the computer C (step ST ₁ ). Moreover, the driver
The forward rotation output of MD ₁ is turned on, and the electric motor M ₁ is driven to rotate forward, and all wheels 2 are rotated forward through the mechanism 3.
The trolley 1 moves upward from the solid line position in Fig. 4 at a predetermined welding speed, and at the same time, the encoder E ₁
starts counting the distance traveled.

Then, the computer C takes in the output of the sensor _S1 , calculates the difference from a predetermined reference value, converts the difference into the length of the moving body 6 in the moving direction (step _ST2 ), and then calculates the converted value. Divide by a constant time t. Note that this constant time t is related to the welding speed, but in this example it is 0.1 seconds (welding speed 10 mm/
seconds). If the above-mentioned division value is positive, the counterclockwise rotation output of driver MD ₄ turns ON.
The electric motor M ₄ causes the moving body 6 to receive the above division value (absolute value).
If the speed is negative, then the driver
The clockwise rotation output of MD ₄ is turned on, and the moving body 6 is moved at the speed of the above-mentioned division value (absolute value) (step ST ₃ ).

Therefore, the position P of the welding point of the torch T is always the welding line.
It will match WL.

Then, after 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 , E ₂ , and E ₄ , and the position information of Pi + 1 is imported into the computer C (step ST _Four ).
Then, the current steering angle is calculated from the output of encoder E ₂ , and the steering direction is set on the Xi+1 axis and the vertical axis 5.
Replace a with the coordinates of the origin Oi+1, and perform coordinate transformation on the Pi and Pi+1 positions in the new coordinate system. And the direction of the straight line passing through Pi and Pi+1 (welding line
(direction of WL ₁ ) (step ST ₅ ), further calculates the direction of a line perpendicular to the straight line on the surface of plate _W1 , and further calculates the torch angle θ with respect to the direction of the perpendicular line (step ST 5). ST ₆ ), and furthermore, the torch angle θ is divided by a constant time t. If the division value θ/t is positive, the clockwise rotation output of driver MD ₅ turns ON, and motor M ₅
The torch T is rotated to the right at the speed of the above-mentioned division value (absolute value). Conversely, if it is negative, the counterclockwise rotation output of driver MD ₅ is turned on, and the torch T is rotated at the speed of the above-mentioned division value (absolute value). to the left (step
_ST7 ).

Therefore, even if the welding line WL is a curve, the torch T
The angle with respect to the weld line WL is almost constant.

Furthermore, the preset welding speed (10mm/
Multiply the constant time t (0.1 seconds) by Pi, Pi +
1, the position of the next virtual welding point Pi+2 that is separated from the Pi+1 position by the multiplication value (distance L ₁ , that is, 1 mm in this example), that is, the Pi+2 position that will be reached after a certain period of time t has elapsed. Calculate (step ST ₈ ). Furthermore, Pi+2
A certain distance L ₂ from the position to the left and right direction of the trolley 1 (the current moving direction of the moving body 6) (that is, the reference position of the moving body 6 is set in advance, and the position of the welding point is determined at the reference position of the moving body 6). The next virtual position Oi+2 of the vertical axis 5a, which is separated from the cart 1 by a distance (distance between P and the vertical axis 5a), is calculated (step ST ₉ ). Furthermore, the distance l between the current position Oi+1 of the vertical axis 5a and the next virtual point position Oi+2 is calculated, and the distance l is divided by a certain time t (step
_ST10 ). Then, the division value l/t is sent to the driver MD ₁
(step _ST11 ), and the trolley 1 is made to run at the speed of the divided value.

Therefore, even if the welding line WL is a curve, the welding speed is always approximately constant.

Then, calculate the direction of the straight line passing through Oi+1 and Oi+2, and the angle φ of that straight line with respect to the Xi+1 axis
(that is, the angle of the straight line with respect to the current steering direction of all wheels 2) is calculated (step ST ₁₂ ), and further the angle φ is divided by the time t. If the division value φ/t is positive, the counterclockwise rotation output of the driver MD ₂ is turned on, and all wheels 2 are steered to the left at the speed of the division value (absolute value), and conversely, if it is negative, The clockwise rotation output of the driver MD ₂ is turned on, and all wheels 2 are steered to the right at a speed equal to the division value (absolute value) (step ST ₁₃ ).

Therefore, even if the welding line WL has an extremely large uneven curve, the torch T, mechanism 9, and truck 1 will not collide with the plate material _W2 .

Then, the position information of Pi+1 is replaced with the position information of Pi, and the same operation as last time is repeatedly performed.

As described above, the output value of sensor S ₁ is almost constant, the torch angle with respect to welding line WL ₁ is almost constant, and the welding speed is almost constant regardless of the direction of welding line WL ₁ . Furthermore, the speeds are controlled as described above so that the distance between the trolley 1 and the welding line WL ₁ is almost constant, and in the end, the welding line WL ₁ moves from the bottom to the top in Fig. 4. It will be automatically welded.

When the truck 1 finally collides with the plate W ₂ as shown by the two-dot chain line 1' in Figure 4, the output of the detector S ₂ changes.
It becomes ON. Then, the amount counted (traveling distance) by the encoder E ₁ up to that point is temporarily stored in the memory MEM, and the driver MD ₁ is turned OFF and the cart 1 is stopped. Then, the clockwise rotation output of the driver MD ₃ is turned on, and the rotating body 5 is rotated to the right.
Moreover, counting by encoder _E3 is started. And when the count amount reaches K ₁ ,
In other words, when the torch T reaches the T'' position from the two-dot chain line T' in Fig. 4, the driver MD ₃ is turned OFF.
The rotating body 5 is stopped, and the power source WS is also turned off. Therefore, at this point, welding for weld line WL ₁ is completed.

Furthermore, the reverse rotation output of driver MD ₁ is
When the signal is turned ON, the truck 1 moves backward, and counting by the encoder _E1 is started. When the count reaches K ₂ , that is, when the truck 1 reaches the position 1' shown by the two-dot chain line in FIG. 5, the driver MD ₁ is turned OFF and the truck 1 is stopped. Ru.

Furthermore, the clockwise rotation output of the driver MD ₃ is turned on again, the rotating body 5 is rotated clockwise, and counting by the encoder E ₃ is started.
Then, when the count reaches K ₃ , that is, when the torch T reaches the position T'' on the two-dot chain line in Figure 5 from the position T'' on the two-dot chain line in Figure 5, the driver
MD ₃ is turned OFF and rotating body 5 is stopped.

Furthermore, the left rotation output of driver MD ₂ is
ON, all wheels 2 are steered to the left, and counting by encoder E ₂ is started.
When the count reaches K ₄ , that is, when all the wheels 2 are steered 90 degrees to the left and are facing left in Fig. 5, the driver MD ₂
OFF, and the steering is stopped. Further, the forward rotation output of the driver MD ₁ is turned ON, and the trolley 1 moves to the left in FIG. When the truck 1 collides with the plate W ₂ as shown by the two-dot chain line 1' in FIG. 5, the output of the detector S ₂ is turned ON, the driver MD ₁ is turned OFF, and the truck 1 is stopped.

Furthermore, the clockwise rotation output of driver MD ₂
ON, all wheels 2 are steered to the right, and the encoder E ₂ starts counting. When the count reaches K ₅ , that is, when all the wheels 2 are steered 90 degrees to the right and point upward in Fig. 5, the driver MD ₂
OFF, and the steering is stopped. Then, the forward rotation output of driver MD ₁ is turned on,
Truck 1 moves forward. Then, the roller 10 finally collides with the vertical surface of the plate material W ₂ , the output of the sensor S ₁ is released from the limit, the release output signal turns off the driver MD ₁ , and the cart 1 stops at the position shown in Fig. 6. be done.

Furthermore, the left rotation output of driver MD ₃ is
When turned ON, the rotating body 5 is rotated to the left, and counting is started by the encoder _E3 . When the count reaches _K6 , that is, when the torch T reaches the position T' from the position T shown by the two-dot chain line in FIG. 6, the driver MD ₃ is turned off and the rotating body 5 is stopped.

Furthermore, the clockwise rotation output of driver MD ₂
ON, all wheels 2 are steered to the right, and counting is started by encoder _E2 . When the count reaches _K7 , that is, when all the wheels 2 are steered 90 degrees to the right and turn to the right in FIG. 6, the driver MD ₂ is turned off and the steering is stopped.

Then, the power supply WS is turned ON again, and the right rotation output of the driver MD ₃ is also turned ON, so that the rotating body 5 is rotated clockwise, and the encoder E ₃ starts counting. When the count reaches K ₈ , that is, the torch T reaches the two-dot chain line in Figure 6.
When the driver reaches the T position from the T' position,
MD ₃ is turned OFF and rotating body 5 is stopped. Therefore, the welding line WL ₂ between the two-dot chain line T' position and the T position in FIG. 6 is automatically welded.

Then, the forward rotation output of driver MD ₁ is turned ON, and the count amount (from the welding start position in Fig. 4) that was once stored in the memory MEM is
(amount equivalent to the traveling distance of trolley 1 to position T')
The counting by the encoder _E1 is restarted using the initial value as the initial value, and the operations after step _ST2 described above are executed again. Therefore, the welding line WL ₂ will be automatically welded from the position of the two-dot chain line T in FIG. 6 to the right.

Then, welding lines WL ₂ and WL ₃ are automatically welded in the same manner as described above, and finally when the count amount by encoder E ₁ reaches K ₉ , that is, when the torch T reaches the welding line
In Figure 4 of WL ₃ , when the trolley 1 travels until it reaches the lower end position, the power supply WS is turned off.
Further, driver MD ₁ is also turned off, truck 1 is stopped, and automatic welding of welding line WL is completed.

As is clear from the above explanation, each weld line
The areas near the intersections of WL ₁ to WL ₃ are automatically welded based on the subroutine flowchart in Figure 10, and other areas are welded in accordance with the subroutine flowchart in Figure 9.
Based on the flowchart in (b), so that the output value of sensor S ₁ is approximately constant, and the torch angle with respect to welding line WL is approximately constant, respectively.
Furthermore, automatic welding is performed while controlling the respective speeds so that the welding speed is almost constant regardless of the direction of the welding line WL, and furthermore, so that the distance between the trolley 1 and the welding line WL is almost constant. Become.

As is clear from the above description, in this invention, even if the welding line tracing sensor is only _S1 , the first to fourth sensors
By means _A1 to _A4 , (a) the amount of approach and distance of the torch T to the welding line WL (the amount of movement of the moving body 6), the welding line
The torch angle with respect to WL, the speed of the truck 1 and the steering angle of all wheels 2, or (b) the amount of approach and distance of the torch T with respect to the welding line WL (the amount of movement of the moving body 6),
Torch angle with respect to welding line WL and all wheels 2
The steering angle of the can be controlled. That is, even with one welding line tracing sensor, multiple elements can be controlled by the control device C, so there is no need to mount a large number of sensors on the welding equipment as in the past, and the structure can be simple, lightweight, and compact. Furthermore, by detecting the side wall of the vertical workpiece with the detector _S2 , it is possible to at least stop the cart 1, and by stopping it, another sequential control can be performed for the parts that cannot be automatically welded by the first to fourth means. It is also possible to perform such operations, and the device of the present invention can be used depending on the shape of the workpiece.

[Brief explanation of drawings]

Each of the figures shows an embodiment of the present invention.
The figure is a perspective view for explaining the whole thing, Figure 2 is a bottom view of the traveling cart, Figure 3 is a plan view of the mechanism in which the tip part rotates around an imaginary point, and Figures 4 to 7 are explanatory diagrams of the operation. , FIG. 8 is a block diagram of the control device, and FIGS. 9A and 9B, and FIG. 10 are flowcharts for explaining the operation. In the figure, W ₁ ...Work (horizontal plate material), W ₂
...Work (vertical plate), WL (WL ₁ to _{WL 3} )...
Welding line, T...Welding torch, P...Position of welding point of torch T, 1...Traveling trolley, 2...Wheels, 4
... Steering mechanism, 5 ... Rotating body, 5a ... Vertical axis,
6... Moving body, 9... Mechanism whose tip is horizontally rotated around an imaginary point, 9j... Mechanism 9 tip (holding member for torch T), 10... Tracing roller, S ₁ ... ... Welding line tracing sensor, C... Control device, S ₂ ... Detector, A ₁ ... First means for controlling the movement of the moving body 6 so that the output value of sensor S ₁ is almost constant, A ₂ ...Torch T welding line WL
A second means for controlling the rotation of the mechanism 9 so that the angle relative to the welding speed is approximately constant, A ₃ . . . A third means for controlling the speed of the trolley 1 so that the welding speed is approximately constant, A ₄ . This is a fourth means for steering and controlling all the wheels 2 so that the distance between the welding line WL and the truck is approximately constant.

Claims (1)

[Claims] 1 A traveling bogie with a steering mechanism connected to all wheels,
a rotating body supported by the traveling truck and capable of rotating around a vertical axis; a moving body supported by the rotating body and movable in a direction perpendicular to the vertical axis; A mechanism whose tip part is horizontally rotated about a virtual point, a welding torch holding member integrated with the tip part of the mechanism, a welding line tracing sensor supported by the holding member, and a welding line tracing sensor provided on the traveling carriage. a detector that detects a side wall of a vertical workpiece and stops at least a traveling cart; and a control device configured to automatically weld a weld line of the workpiece based on the output of the weld line tracing sensor, and the control device includes: a first means for calculating the difference between the output value from the welding line tracing sensor and a preset reference value, and controlling the movement of the moving body so that the difference is substantially constant; Calculating the direction of a straight line passing through both positions (direction of the welding line) from the position information of the welding point, and calculating the torch angle with respect to the straight line direction, so that the angle of the welding torch with respect to the welding line is approximately constant. a second means for controlling the rotation of the rotation mechanism so that the next virtual welding point that will be reached after the elapse of the predetermined time is on a straight line passing through the positions of both the previous and current welding points; a third means for calculating the position and controlling the speed so that the running speed (welding speed) of the traveling trolley is substantially constant from both the current position information and the position information after the certain period of time has elapsed; In order to maintain the distance between the traveling bogie and the welding line approximately constant by calculating the direction of a straight line passing through both positions, and calculating the angle of the straight line with respect to the current steering direction of all the wheels. and fourth means for steering control.