JPS6142288B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling a position control device, and more particularly to a method of controlling a robot having a plurality of controlled objects or tools.

2. Description of the Related Art Conventionally, it has been known to control the position of a torch or a coating gun in, for example, an automatic welding machine or an automatic coating machine using a PTP (Point To Point) method. In such an automatic welding machine, for example, the object to be welded (work) is so large that it may exceed the movable range of the torch. In this case, the entire length of the workpiece is covered by moving the workpiece or using multiple torches. When the workpiece is, for example, a ship's hull, it is very difficult to move it, and for this reason two or more torches are moved simultaneously for continuous welding. The present invention is directed to improving the control method of such a position control device having a plurality of tools.

FIG. 1 is an overall perspective view showing an automatic welding apparatus that forms the background of this invention and in which this invention is implemented. This automatic welding device will be briefly explained below in order to facilitate understanding of the present invention. The length direction (X
In the axial direction) horizontal guides 2, 2 are fixedly provided above the table 1. This horizontal guide 2,2
Rails 3, 3 are disposed above, respectively.
A running beam 4 is placed on the horizontal guides 2, 2 and is movable in the X-axis direction on the rails 3, 3, and is driven by a motor 5. The running beam 4 is movable in the width direction (Y-axis direction) of the table 1 and is driven by a motor 7.
The movable body 6 is supported by the movable body 6. Further, a column 8 is provided which is supported by the movable body 6 and movable in the vertical direction (Z-axis direction) and which is driven up and down by a motor 9.

A torch mount 10 is attached to the lower end of the column 8.
is rotatably provided around a vertical axis. This torch fixture 10 holds a torch T and is rotationally driven by a motor 11 to adjust the orientation angle of the torch T with respect to the workpiece. In this example,
Another set of similar devices is provided in a similar combination. It is well known that the rotational speed of each motor 5, 7, 9, 11, the welding current applied to the torch T, and the torch position are controlled by a (positioning) control device (not shown).

In such an automatic welding apparatus, the torch T is position-controlled to a preprogrammed point position with respect to the X, Y, and Z axes, for example, by a PTP method. In the longitudinal direction of the table 1, there are two positioning devices and therefore torches T and T.
, but its central part is shared by the two torches T,T. In other words, 2
Each of the two torches T has its own area where there is no interference from other torches, and also has an area where they interfere with each other. Therefore, there is a possibility that the two torches T, T may intersect or collide in this interference area. Therefore, in that case, it is conceivable to stop one and move the other.

However, in automatic welding machines or automatic painting machines, once the operation of the torch or paint gun is started, it is not possible to stop the operation midway.
This is because it has a serious adverse effect on the finish of welding or painting, leading to a decline in the quality of the finish.

Therefore, the main object of the present invention is to provide a control method for such a position control device, which controls a plurality of controlled objects without stopping them in the middle of their operations and without mutual interference.

FIG. 2 is a blotter diagram outlining the invention. In configuration, this embodiment has, for example, three sets of positioning devices, each of which has a positioning device control device PC as described above.
1, PC2 and PC3 are provided. These positioning control devices PC1, PC2, and PC3 each have a remote control box RC for manually operating a corresponding positioning device (not shown) and for teaching a user program.
1, RC2, and RC3 are connected. Further, a control device CPU is provided to centrally control each positioning control device PC1, PC2, PC3.

The control device CPU includes each control device PC1 to PC.
A system program for controlling the computer 3 and a memory MRY for storing each of the user programs are coupled. Then, the control device CPU executes the positioning control device based on the user program and system program read from this memory MRY.
Give position commands to PC1 to PC3. Therefore, each of the positioning control devices PC1 to PC3 issues position commands for each axis X, Y, and Z as shown in FIG. 1 and system speed (combined movement speed) to the corresponding positioning device. and give. Then, upon receiving a null signal (zero signal: obtained when the target position is reached from the servo amplifier of the servo system) from the corresponding positioning device, it requests a position command from the control device CPU.

That is, each positioning control device PC1 to PC3
The controlled object (not shown) is moved to each axis
Position control in Y and Z directions.

These positioning control devices PC1, PC2, PC3
The controlled object whose position is controlled by
It has 3. That is, area A1 corresponds to positioning control device PC1 (a controlled object controlled by it), A2 corresponds to PC2, and A3 corresponds to PC3. Area A12 is an area where two positioning control devices PC1 and PC2 interfere with each other, and area A23 is an area where two positioning control devices PC1 and PC2 interfere with each other.
This is an area where PC3 and PC3 interfere with each other. Therefore, the area "A1-A12" is a unique area of the positioning control device PC1, and the area "A2-A1" is a unique area of the positioning control device PC1.
2-A23" is an area unique to the positioning control device PC2, and "A3-A23" is an area unique to the positioning control device PC3.

FIG. 4 is an illustrative diagram for explaining the control method of the present invention, in which two positioning control devices PC1,
The case where automatic welding or automatic painting is performed using PC2 is shown below.

First, in FIG. 4a, one positioning control device PC1 sequentially interpolates points P11 in area A1, point P12 in area A12, point P13 in area A12, and points P14 and P15 in area A1. Then, the position is controlled and welding is performed (welding on) from points P11 to P13. The other positioning control device PC2 moves from point P21 of area A2 to area A.
Point P22 of 2 - Point P23 of area A2 - Area A
The positions of the two points P24 and P25 are controlled by sequential interpolation, and welding is turned on from points P22 to P24. In such a case, one positioning control device PC1 enters the interference area A12, but the other positioning control device PC2 enters the interference area A1.
Do not enter 2. Therefore, the control device CPU
, two positioning control devices PC1, PC
2, it is determined that the two controlled object torches (not shown) will not interfere even if they are welded at the same time.
1. Judgment is made based on the user program that commands the PC 2 to specify the point positions as described above. ) Therefore, this control device CPU allows simultaneous work (welding) by the two positioning control devices PC1 and PC2.

Next, in FIG. 4b, one of the positioning control devices PC1 moves from point P11 of area A1 to point P12 of area A12 to point P13 of area A12 to
Sequentially position to point P14 in area A1, and
Welding is on from P11 to P13. The other positioning control device PC2 moves to point P21- in area A2.
Point P22 in area A12 - Point P2 in area A12
3-Sequentially position to point P24 in area A2,
Welding is turned on from points P22 to P23. In such a case, two positioning controllers PC1 and
Both PC2 enter the interference area A12, but the two torches do not interfere. Therefore, the control device CPU judges this and causes the two positioning control devices PC1 and PC2 to simultaneously perform welding.

Furthermore, in FIG. 4c, one of the positioning control devices PC1 sequentially positions the points P11 in area A1, P12 in area A12, P13 in area A12, and points P14 and P15 in area A1,
Welding is turned on from points P12 to P13. The other positioning control device PC2 is at point P2 in area A2.
1 - Point P22 of area A12 - Point P23 of area A12 - Point P24 of area A2 are sequentially positioned, and welding is turned on from point P22 to P23. In such a case, the positioning control devices PC1 and PC2 both enter the mutual interference area A12 and reach the point P.
Interference occurs between points 12 and P13 and points P22 and P23. Therefore, the control device CPU determines this using two user programs, and moves one of the positioning control devices PC1 to the current position (point P1).
1), and the other positioning control device PC2
performs welding with priority. When the other positioning control device PC2 stops at point P24 (a point outside area A12 and at which welding is off), one positioning control device PC1 is allowed.

Such decisions by the control device CPU are made in a preprogrammed order by the system program. That is, the control device CPU reads the user program programmed (taught) to each positioning control device PC1, PC2 from the memory MRY, and controls each positioning control device individually and overall. This will be explained below with reference to the flowchart of FIG.

FIG. 5 is a flowchart showing an example of a system program based on the present invention. As an example, this flowchart is applied to an automatic welding machine as shown in FIG. 1, in which positioning control devices PC1 and PC2 are controlled as shown in FIG. 4. It should be noted in advance that the interference area A12 and therefore the non-interference area (unique area) in the following explanation is determined depending on the mutual relationship with the positioning control devices PC1 and PC2. In other words, these interference areas and non-interference areas are
2. It changes depending on the situation at that time. This is because when one controlled object moves, it changes the movement range shown in FIG. 3 or 4, for example A1.
Because it also moves.

First, in response to the Nu11 signal from the corresponding servo system, the positioning control device PC1 to the control device
Request a position command to the CPU.

Accordingly, in the control unit CPU, as indicated by block 101, this control unit PC is programmed based on the corresponding user program from the memory MRY.
When the steps (point positions) are sequentially advanced according to step 1, find the movement range to the point position outside the mutual interference area A12 as described above and where welding is off (welding is not performed only by position control). . The reason for using "welding off" as a condition here is that in an automatic welding machine, once started and then stopped midway, the quality of the finished product deteriorates. When controlling only the position, such a "no work" condition is unnecessary.

Next, in this control device CPU, as shown in block 102, the positioning control device PC
When controlling the position within the movement range determined as described above using 1, it is determined whether the corresponding controlled object (torch) enters the mutual interference area A12 as shown in FIG. The above-mentioned blocks 101 and 102 cooperate to constitute an interference region determination step.

Then, if the positioning control device PC1 enters the interference area A12, that is, if YES, the control device CPU controls the block 10.
3, the other positioning control device PC2
It is determined whether the object has already entered or is about to enter the interference area A12. this is,
This is done by checking the "area A12 entered" flag in the work area of the control device PC2 in the system program (memory MRY) held by the control device CPU. This block 103 constitutes an entry determination step.

At this time, if YES, that is, if the positioning control device PC2 is about to enter or is entering the interference area A12 (if the flag is set), the control device CPU executes the steps shown in block 104. When the positioning control device PC2 sequentially advances the steps, the movement range outside the interference area A12 and up to the welding-off point position is determined. This is done by reading the corresponding user program from memory MRY.

Next, in this control device CPU, as shown in block 105, the positioning control device PC
1 and PC2 are likely to collide. This is done by comparing the movement ranges of each of the positioning control devices PC1 and PC2 determined as described above. Blocks 104 and 105 described above work together to constitute an interference determination step.

If YES, that is, if there is a possibility that the torches controlled by the two positioning controllers PC1 and PC2 will collide, the controller CPU will block 106, for example by inhibiting the next position command. As shown, one control device PC
The position control by 1 is stopped. This control device
The stopping position of PC1 is the point where the Nu11 signal is obtained, that is, the current step, as described above. At this time, it is easy to understand that the welding is off because the condition is "welding off." This block 106 constitutes the prohibition step.

Next, as shown in block 107, the control device CPU determines whether or not the positioning control device PC2 is stopped based on the movement range determined as described above. That is, it is determined whether the other positioning control device PC2 is in a stopped state to avoid interference.

At this time, if NO, that is, if the positioning control device PC2 is in operation, the check for interference in the control device CPU ends. vice versa,
If YES, that is, if the positioning control device PC2 has stopped, the control device CPU will:
As shown in block 108, the above-described series of processes is continued with PC1 and PC2 reversed. It goes without saying that this reverse process may be programmed as a separate routine.

In addition, in the above-mentioned block 102, that is, the interference area judgment step, if the judgment of "Does it enter the PC1 area A12?" is NO, the control device CPU executes the positioning control device as shown in block 109. Reset the "area A12 entry" flag in the work area of PC1.
This shows that the movement range (PC1) obtained based on the request from the control device PC1 is the area A1 where there is no other interference, and the control device CPU
Then, in block 110, the memory MRY
control device by the user program read from
Give the command for the next step to PC1. Blocks 109 and 110 described above together constitute the tolerance step.

Also, in the aforementioned block 103, that is, the entry judgment step, "Is PC2 already in the area?"
When the judgment is NO, or in block 105, that is, the interference judgment step,
When it is determined NO in the judgment "Is there a collision between PC1 and PC2?", as shown in block 111 in the control device CPU, the positioning control device PC1
Set the "area A12 entered" flag in This means that even if one positioning control device PC1 advances the steps sequentially, the other positioning control device
This means that there is no interference with PC2. Therefore, the control device CPU continues to block 1.
At step 10, a command for the next step is given to the control device PC1 by the user program read from the memory MRY. Blocks 111 and 1 above
10 together constitute the permissible step.

As described above, according to this embodiment, a plurality of controlled objects can be controlled in parallel while preventing mutual interference without stopping work such as welding or painting in the middle, so it is particularly useful for automatic welding machines or Suitable for automatic coating machines, etc.

In the above embodiment, when there is interference, one positioning control device PC1 is started on the condition that the other positioning control device PC2 moves out of the interference area A12 and stops.
This may be done by reading the sequential interpolation point information of the other positioning control device PC2 in the control device CPU, and starting when the interpolation point is out of the interference range. That is, in the case shown in FIG. 6, in the above embodiment, one positioning control device
PC1 stopped at point P11, waited until the other positioning control device PC2 stopped at point 25, and then started later. If this is done, there is a problem in that the working time is long and time consuming.

Therefore, in this embodiment, the control device CPU monitors the sequential interpolation points of the positioning control device PC2, and this positioning control device PC2 monitors the interpolation point P2.
3' or when the point P23'' is reached, one of the positioning control devices PC1
Give the command for the next step to . In this way, the waiting time of the positioning control device PC1 is reduced.

As described above, according to the present invention, the positions of a plurality of controlled objects can be controlled without mutual interference and without interrupting the work. Incidentally, in the present invention, the control circuit can also be configured by hardware without using a microprocessor or the like.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing an automatic welding device that forms the background of the present invention and in which the present invention can be implemented. FIG. 2 is a schematic block diagram of the invention. FIG. 3 is an illustrative diagram showing the movable range (area) of each positioning control device. FIG. 4 is a position diagram showing each case for explaining the present invention. FIG. 5 is a flowchart showing an example of a system program based on the present invention. FIG. 6 is a positional diagram for explaining another embodiment of the present invention. In the figure, CPU is the (supervising) control unit, MRY
is memory, PC1, PC2, PC3 are positioning control devices, RC1, RC2, RC3 are remote control boxes, T is a torch, 101, 102 are interference area judgment steps, 103 is an approach judgment step, 104,
105 is an interference determination step, 106 is a prohibition step, and 109, 110, and 111 are permission steps.

Claims (1)

[Scope of Claims] 1. Controls the position of a plurality of controlled objects sequentially to preprogrammed point positions, performs continuous work between the point positions, and controls other controlled objects in accordance with this sequential position control. A control method for such a position control device, in which a non-interference area that does not cause mutual interference with a controlled object and an interference area that causes mutual interference in relation to another controlled object are determined, In response to a request from a control body, it is determined whether a movement path of this one controlled body to the next point position within the non-interference area where the controlled body does not perform work includes the interference area. an interference region determination step for determining whether or not another controlled object has entered or is about to enter the interference region, in response to the determination that the interference region is included in the interference region determination step; an approach determination step for determining whether or not the one controlled object and another controlled object will interfere in response to the determination that the controlled object is entering or is about to enter in the entry determining step; an interference determination step for determining the interference region; a prohibition step for preventing the next position command from being given to the one controlled object in response to the determination of interference in the interference determination step; In response to determining in the determining step that the moving path of the one controlled object does not include the interference region, or in response to determining that the other controlled object enters the interference region in the entering determining step. In response to determining that the one controlled object and the other controlled object do not interfere with each other in the interference determining step, A method for controlling the position control device, comprising: a step of allowing a next position command to the one controlled object.