JP2003136446A - Control method and control system of robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent mutual interference of robots and reduce action time of robots when a plurality of robots work in close proximity to each other. SOLUTION: Each operation route of four articulated robots 14a-14d is divided into three sections including a first section 86 from a basic posture to reach near a vehicle body 40, a second section 88 for welding and a third section 90 for taking a shunting posture after welding. At the first section 86, mutual interference of each articulated robot is prevented by performing synchronous control (step S2-S6) with a synchronous control program 74. At the second section 88, action time is reduced by executing multi-task control (step S8) with a multi-task control program 76. At the third section 90, a synchronous control is executed by a second synchronous control program 78 (step S9-S14).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot control method and control system, and more particularly to a robot control method and control system for controlling a plurality of robots performing a predetermined work on a work by a controller.

[0002]

2. Description of the Related Art Many articulated robots are used for welding, painting, assembling work and the like in factory production lines.

With the widespread adoption of articulated robots, it is desired to improve the productivity per line length by arranging them in high density on the production line, and a plurality of articulated robots can work in one process. The number of cases where the robots operate while sharing the work, and the number of cases where an articulated robot works while a work, a jig, a transfer device, etc. coexist are increasing. In this case, since the multi-joint robots are arranged at high density, the possibility of mutual interference between the multi-joint robots increases. Therefore, it is necessary to perform the operation program or teaching with sufficient care so that the articulated robots and other obstacles do not interfere with each other.

Further, when a plurality of articulated robots are densely arranged and work is performed on one work at the same time, it is desirable that the plurality of articulated robots cooperate with each other, and the cooperative operation is realized. Therefore, a plurality of articulated robots that perform work on one work may be controlled by one controller.

[0005]

As a method of preventing interference between articulated robots, a method of simultaneously operating a plurality of robots one step at a time and determining an interfering step in this process to set an interlock for preventing interference. (For example, refer to Japanese Patent Laid-Open No. 10-264058).

However, this method is intended only to prevent interference between the robots, and does not consider the operation time. Therefore, if the number of interlock settings increases, the waiting time of each robot becomes long, and as a result, the operation time becomes long.

In the first place, one of the purposes of arranging the multi-joint robots at a high density is to improve the productivity, and it is disadvantageous that the operation time is long against this purpose.

The present invention has been made in consideration of such problems, and when a plurality of robots operate in a state of being close to each other, mutual interference between the robots can be prevented and the operation time can be shortened. An object of the present invention is to provide a robot control method and control system.

[0009]

A robot control method according to the present invention is a robot control method for controlling a plurality of robots performing a predetermined work on a work by a controller, wherein a plurality of motion paths of each robot are provided. It is characterized in that the robots are controlled by dividing the sections into multi-task control and synchronous control for each section.

In addition, the section is based on a basic posture of each robot as a starting point, a first section reaching the vicinity of the work, and an ending point of the first section as a starting point, and the section is predetermined with respect to the work. It may be configured to include a second section in which the work described above is performed, and a third section that starts from the end point of the second section and reaches a retracting posture in which the work is retracted.

In the first section and the third section, the robots may be controlled by the synchronous control, and in the second section, the robots may be controlled by the multitask control. .

Further, work points for performing a predetermined work on the work are arranged in an annular shape, and as the second section,
The work point is assigned to each of the robots,
The work points assigned to the second section of each robot may be set so that work is performed in the same rotation direction.

Further, a robot control system according to the present invention is a robot control system in which a controller controls a plurality of robots performing a predetermined work on a work, and a synchronization control unit for synchronously controlling the robots. A multi-task control unit that controls each robot by multi-task control, and an operation path of each robot is divided into a plurality of sections, and the synchronization control section or the multi-task control section is applied to each section. It is characterized by being done.

By doing so, it is possible to selectively apply the multitask control and the synchronous control according to the characteristics of each section divided into a plurality of sections.
As a result, when a plurality of robots operate in close proximity, mutual interference between the robots can be prevented and the operation time can be shortened.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the robot control method and control system according to the present invention will be described below with reference to FIGS.

This embodiment basically controls a plurality of articulated robots with a single controller, and performs synchronous control when each articulated robot moves from the basic posture to the vicinity of the work. In addition, each articulated robot is controlled by multitask control in the section where the work is being performed.

As shown in FIG. 1, a robot control system 10 according to the present embodiment is arranged in a machine frame 12 and is provided with
The robot group 16 includes the multi-joint robots 14a, 14b, 14c, and 14d, and the controller 18 that controls the robot group 16 based on predetermined data.

The articulated robots 14a to 14d are arranged in a two-row, two-row arrangement, and are arranged in high density close to each other. Further, since each of the articulated robots 14a to 14d is installed so as to extend in the same direction, it is possible to work on a predetermined work simultaneously and intensively.

All four articulated robots 14a to 14d have the same structure, and as shown in FIG. 2, a base which is rotatable with respect to an axis J1 which is the central axis of the base 20 set in the machine frame 12. Axis J in the lateral direction of the part 22 and the base part 22
Centering on a first arm portion 24 that can swing about 2; a second arm portion 26 that can extend and contract with respect to the first arm portion 24; and an axis J4 that is the axial center of the second arm portion 26. A rotatable first wrist portion 28, a second wrist portion 30 which can be swung about a shaft J5 in the distal end lateral direction of the first wrist portion 28, and a shaft J6 which is an axial center of the second wrist portion 30. It is composed of a tip portion 32 rotatable around the center and an end effector 34 attached to the tip portion 32.

The end effector 34 is a so-called C-type gun unit for performing welding, and has a pair of welding electrodes 36a and 36b which are opened and closed. This welding electrode 36a,
When 36b is closed, the contact point is the welded point TCP
(Tool Center Point), which is set on the axis J6.

Further, the rotation angles of the base portion 22, the first arm portion 24, the first wrist portion 28, the second wrist portion 30 and the tip portion 32 on the axes J1, J2, J4, J5 and J6 are θ1, θ2, θ4. , Θ5 and θ6. Also, the second
The extension / contraction amount of the arm portion 26 with respect to the first arm portion 24 is set to λ3.
And The amount of expansion / contraction λ3 is treated in the same way as the rotation angle θ
Also noted as 3.

A point that intersects the axis (axis J1) at the end of the base 20 is defined as an origin O. With this origin O as a reference, the tip side is the Z axis, and the width direction of the articulated robots 14a to 14d is Y.
X axis, Y axis and Z axis are perpendicular to the front side of the paper of FIG.
It is defined as an axis (not shown).

With this structure, the articulated robots 14a to 14d can freely move. As shown in FIG. 3, the vehicle body 40, which is a workpiece, is placed on the production line 42, and the vehicle body 40 is It is possible to intensively weld the opening 44 of the.

As shown in FIG. 4, the controller 18 is
A CPU (computer) 50 as control means for controlling the four articulated robots 14a to 14d, a ROM 52 and a RAM 54 that are storage units, and a hard disk 5
6, a hard disk drive (HDD) 58 for accessing data, and an external recording medium 60a (for example,
It has a recording medium drive 60 for controlling a flexible disk, an optical disk, etc., and a LAN control unit 62 having a function of communicating with an external device.

The LAN control unit 62 is connected to a controller (not shown) of the production line 42 and can detect the state of the production line 42.

Further, the controller 18 is instructed by the CPU 50 to move each of the articulated robots 14a to 14a.
servo amplifiers 64a, 64b, 64c for operating d,
64d, and inverters 66a, 66b, 66c, 66d that act so as to flow current to the welding electrodes 36a, 36b (see FIG. 2) in response to a welding command from the CPU 50.

Further, the controller 18 can be connected to a monitor, a keyboard and a mouse (not shown) as required, and the OS 69 stored in the hard disk 56.
Various processes are possible under the control of.

The OS 69 is operated by the CPU 50 while being loaded in the RAM 54, and controls the entire controller 18. The OS 69 is a so-called multitask control OS capable of time-division processing, and can process a plurality of programs in parallel.

Inverters 66a, 66b, 66c, 66
transformers 68a, 68b, 68 for generating a high voltage between the robot d and the robots 14a, 14b, 14c, 14d.
c and 68d are provided. These transformers 68a
~ 68d welding electrodes 36a, 36b (see FIG. 2)
A high voltage is generated at both ends of the vehicle body 40 to weld the vehicle body 40 held by the welding electrodes 36a and 36b.

In addition to the OS 69, the hard disk 56 stores a path table 70 indicating the operation paths of the articulated robots 14a to 14d, and an operation program 72 generated from the path table 70.

The operation program 72 includes a first synchronization control program 74 (synchronization control section) for controlling the first section 86 (see FIG. 6) which is the preceding stage in the operation path of each of the articulated robots 14a to 14d. , The second section 88 which is the middle section
And a second synchronization control program 78 (synchronization control unit) for controlling the third section 90 which is the latter stage unit.

As shown in FIG. 5, the path table 70 is
"Teaching posture point" column 70a, "Gun unit orientation" column 7
0b, "TCP position" column 70c, "each axis angle" column 70
It is composed of d and "section" column 70e.

Although the path table 70 corresponding to the articulated robot 14a is shown in FIG. 5 as an example, the path table corresponding to the articulated robots 14b to 14d has the same format.

The "teaching posture point" column 70a shows the numbers of the teaching posture points P (n) and Q (n) (working points) that make up the motion path. Of these, the teaching posture point P (n) is a teaching posture point that defines only the posture of the articulated robot 14a in space, and the teaching posture point Q (n) is the vehicle body 40.
Is a teaching posture point involving welding work.

Here, "(n)" means counter n (n =
0, 1, 2, 3, ...),
For example, if n = 1, P (n) indicates P1. Further, a numerical sequence, a movement command, and a welding command, which will be described later, are also expressed in the same manner.

The "gun unit orientation" column 70b represents the inclination of the end effector 34 in the three-dimensional space, and is indicated by a numerical sequence Vr (n).

The "TCP position" column 70c represents the position of TCP in the three-dimensional space, and is a numerical sequence V
It is represented by (n). The numerical value sequence V (n) is shown in the X, Y, Z coordinate system with the origin O as a reference.

The "each axis angle" column 70d is represented by a numerical sequence Θ (n) representing the posture of the articulated robot 14a.
The numerical sequence Θ (n) is the rotation angle θ of each of the axes J1 to J6.
1 to θ6.

The "section" column 70e is an item referred to when the operation program 72 is generated from the path table 70, and the corresponding teaching posture points P (n) and Q (n) are the first to the first.
It shows which of the third sections 86, 88, 90 (see FIG. 6) it belongs to.

In the path table 70, P0 is set as the basic posture in the first order "0". Further, the last order “12” is a retracted posture, and in the example of FIG. 5, P0, which is the same as the basic posture, is set. That is, the motion path created based on the path table 70 returns to the original posture after performing a predetermined motion such as welding. The basic posture and the retracted posture may be different postures.

As shown in FIG. 6, first to third sections 8
Reference numerals 6, 88, and 90 denote the motion paths of the articulated robots 14a to 14d divided into three sections.

The first section 86 is a section starting from the basic posture of each robot and reaching the vicinity of the vehicle body 40.
The second section 88 is a section where the welding work is performed on the vehicle body 40, starting from the end point of the first section 86. Third
The section 90 is a section starting from the end point of the second section 88 and retracted from the vehicle body 40.

Of these, the first and third sections 86, 9
0 is a section in which the articulated robots 14a to 14d may interfere with each other because the movement amount is relatively large. Further, since the first and third sections 86 and 90 are simple movements only between the basic posture or the retracted posture and the vehicle body 40, the number of taught posture points P (n) is set to be small. Has been done.

As shown in FIG. 7, the second section 88 is a section in which the teaching posture point Q (n), which is a welding work point, is welded to the vehicle body 40 in order. Second section 88
Are set individually for each of the articulated robots 14a to 14d. The welding area 84a is the area where the articulated robot 14a performs welding, the welding area 84b is the area where the articulated robot 14b performs welding, and the articulated robot is referred to as the articulated robot. The region where 14c performs welding is the welding region 84c, and the articulated robot 14d.
A region in which the welding is performed is a welding region 84d.

The welding areas 84a to 84d are set in an annular shape along the peripheral edge of the opening 44 of the vehicle body 40, and the respective welding areas 84a to 84d are adjacent to the teaching posture point Q.
(N) is set collectively. Further, the order of welding is unified in the clockwise direction (direction of arrow A) in FIG. 7. That is, regarding the welding region 84a, the teaching posture point Q11 is first welded, then the teaching posture points Q12, Q13, ... Are welded in the clockwise direction, and finally the teaching posture point Q16 is welded.

The second section 88 has a relatively small amount of movement because the teaching posture points Q (n) adjacent to each other are collectively set in each of the welding areas 84a to 84d. Moreover, since the welding sequence is set in the same direction in each of the welding regions 84a to 84d, the possibility of mutual interference is low. Further, the second section 88 has the teaching posture points Q as many as the number of welding points.
Since (n) is required, the number of necessary operation instructions is large.

As shown in FIG. 8, the first synchronous control program 74 has the commands COM11 to COM13 which are a group of movement commands for the articulated robots 14a to 14d. The robots 14a to 14d are synchronously controlled. The synchronization control will be described later.

The command COM11 is the teaching posture points P0 to P1.
To the teaching posture point P1.
Command from the teaching posture point P2 to P3.

As shown in FIG. 9, the multi-task control program 76 is a first task for controlling the articulated robot 14a.
Subprogram 80a, second subprogram 80b for controlling articulated robot 14b, articulated robot 14c
And a fourth subprogram 80d for controlling the articulated robot 14d.

First to fourth subprograms 80a to 80d
Is a command COM21 (n) which is a movement command and a welding command for each of the articulated robots 14a to 14d,
Command COM22 (n), command COM23 (n), command C
Each articulated robot 14a has an OM24 (n)
14d are controlled by multitask control. Multitask control will be described later.

These commands COM21 (n) to COM2
4 (n), for example, the command COM211 of the first subprogram 80a is from the teaching posture point P3 to the teaching posture point Q11.
To the teaching posture point Q.
11 is a welding instruction.

As shown in FIG. 10, the second synchronization control program 78 has a structure similar to that of the first synchronization control program 74, and commands COM31 to COM33 which are a collection of movement commands for the respective articulated robots 14a to 14d. have. The second synchronization control program 78 uses this command C
Each articulated robot 14a by OM31-COM33
14d is synchronously controlled.

Next, synchronous control and multitask control will be described.

The synchronization control is to synchronize the processes at a predetermined timing when performing a plurality of processes. When the synchronous control is applied to the articulated robots 14a to 14d, each teaching posture point P in the path table 70
It is sufficient to synchronize every (n) and Q (n).

According to this synchronous control, each of the articulated robots 14a to 14d starts and ends simultaneously for each of the teaching posture points P (n) and Q (n). FIG. 11A shows how the synchronous control is applied to the articulated robots 14a and 14b.
It is shown in the time chart of.

In FIG. 11A, the articulated robot 14a
It is assumed that the above operation is represented by operations 92a, 94a and 96a, and the respective operations 92a, 94a and 96a require the same time. The motion of the articulated robot 14b is motion 92.
b, 94b, 96b, the operation 92b takes a long time, and the operations 94b, 96b can be completed in a short time.

First, at time t0, the two articulated robots 14a and 14b start operations 92a and 92b, respectively.

The articulated robot 14b has a maximum speed Vhb.
Then, the operation 92b ends at time t11. On the other hand, the operation 92a can be completed in a shorter time than the operation 92b, but the speed Vla slower than the maximum speed Vha of the articulated robot 14a is set so as to end the operation at the same time t11.
To work with.

Next, at time t11, the two articulated robots 14a and 14b start operations 94a and 94b, respectively.

In this case, contrary to the above case, the articulated robot 14a operates at the maximum speed Vha, and the time t1 is reached.
While the operation 94a is ended at 2, the articulated robot 14b adjusts the speed so as to end the operation 94b at the same time t12, and operates at the slow speed Vlb.

After that, the same operation is performed for the motion 96a and the motion 96b, and the articulated robots 14a, 14b.
b completes all operations at the same time te1.

As described above, according to the synchronous control, since the articulated robots 14a and 14b are controlled so as to be synchronized with each other at a predetermined location, the articulated robots 14a and 14b are controlled at that location.
If the position of 14b is set such that mutual interference does not occur, there is very little risk of mutual interference throughout the synchronization control.

Next, multitask control will be described.

The multitask control is generally a usage mode in which one computer can be simultaneously used by a plurality of users or tasks by using time division processing or the like. The multitask control referred to here is not limited to one computer that performs control, but refers to a control mode in which a plurality of processes are simultaneously processed in parallel and independently.

In the multitask control, generally, the processing time of the computer is finely divided, the processing is switched at each divided time, and a plurality of different processings are executed one after another. Therefore, each user or task is Individual processes can be executed in parallel. This is shown in the schematic time chart of FIG. 11B.

In FIG. 11B, actions 92a, 94a,
96a, 92b, 94b and 96b operate in the same manner as shown in FIG. 11A.

First, at time t0, the two articulated robots 14a and 14b start operations 92a and 92b, respectively.

The articulated robots 14a and 14b operate at the maximum velocities Vha and Vhb, respectively, the operation 92a of the articulated robot 14a ends at time t1, and the operation 92b of the articulated robot 14b operates later than time t1. It ends at t11.

At time t1, the articulated robot 14a
Starts the next operation 94a continuously after finishing the operation 92a. That is, at time t1, the articulated robot 14b is in motion, but the articulated robot 14a does not wait until the motion 92b is completed.
4a is started.

On the other hand, at time t11, when the articulated robot 14b finishes the operation 94b, the articulated robot 14a is in the operation of the operation 94a.
Articulated robot 1 without waiting until 4a ends
4b starts the next operation 94b.

In this way, the articulated robot 14a
Performs operations 92a, 94a, and 96a in this order, and ends these operations at time t12. Articulated robot 1
4b performs operations 92b, 94b, and 96b in this order, and ends these operations at time te2, which is later than time t12.

The articulated robots 14a and 14b are
It is not always necessary to operate at the maximum speeds Vha and Vhb. For example, when the operation time is short like the operation 94b, the operation may be performed at the speed Vlb2 slower than the maximum speed Vhb in consideration of the operation overshoot and the like.

When performing the synchronous control after the multitask control, the articulated robot 14a waits until the time te2 after ending the operation at the time t12, and then starts the synchronous control simultaneously with the articulated robot 14b. Good.

As described above, in the multitasking control, the articulated robots 14a and 14b operate without being restricted by their operation states, so that the operation time can be shortened as a whole. In the example shown in FIG. 11B, the synchronous control shown in FIG. 11A ends the operation at time te1, whereas the multitask control can end at time te2 which is earlier than time te1.

11A and 11B, the synchronous control and the multi-task control have been described for the operation of the two articulated robots 14a and 14b. However, even when the number of the articulated robots is three or more, the synchronous control and the multi-task control are performed. Task control can operate as well.

Next, a method of controlling the articulated robots 14a to 14d using the robot control system having the above-described structure will be described with reference to FIGS.

Before controlling the articulated robots 14a to 14d, an operation program 72 is generated based on the path table 70 and stored in the hard disk 56 in advance.

In step S1 of FIG. 12, the generated operation program 72 is executed. The operation program 72 is loaded into the RAM 54 and then executed by the CPU 50.

Next, in step S2, the operation program 72 confirms via the LAN control unit 62 that the vehicle body 40 has been set at a predetermined location on the manufacturing line 42, and then the first synchronization control program 74 To execute.

Next, in step S3, the counter n
Is initialized to "1".

In step S4, the instruction COM1
Execute (n).

The instruction COM1 (n) is the articulated robot 1
Since it is composed of movement commands 4a to 14d (see FIG. 8).
As shown in FIG. 13, in order to execute the command COM1 (n), the respective movement commands are executed by the servo amplifiers 64a to 64a.
d (see FIG. 4).

That is, in the case of the instruction COM11, the instruction CO
The respective movement commands constituting M11 are sequentially transmitted during CPU operation times 1 to 4. After all the movement commands have been transmitted, the operation of each of the articulated robots 14a to 14d is started based on the command received by the servo amplifiers 64a to 64d at the CPU operation time "5".

The time for transmitting the movement command is extremely small compared to the time for which the articulated robots 14a-14d operate. Therefore, the articulated robot 14a-
In synchronizing the operation of 14d, the time for transmitting these movement commands can be ignored. For example, the servo amplifier 64a may start the operation corresponding to the instruction COM11 from the CPU operation time “2” immediately after receiving the instruction COM11.

Next, in step S5, the first synchronous control program 74 causes the articulated robots 14a to 14d to operate.
Wait until the operation of is completed. In the example of FIG. 13, CP
It waits until U operation time "9", "17", "24".
More specifically, the articulated robot 14a waits until it reaches the taught posture point P1, P2, or P3.

Next, in step S6, the last instruction of the first synchronous control program 74, that is, the instruction COM1.
It is confirmed whether or not the process is completed up to 3, and if there is an unexecuted instruction, the counter n is incremented by "1" in step S7, and then the process returns to step S4. If there is no unexecuted instruction, the process proceeds to the next step S8.

At this point, each articulated robot 14a-1
4d will be located near the vehicle body 40, respectively. More specifically, for example, the articulated robot 14a
Is the teaching posture point Q11 at the start of welding in the welding area 84a.
(See FIG. 7).

As described above, the first synchronization control program 74
When the articulated robots 14a to 14d are operated by the above, the posture teaching posture points P (n) are synchronized with each other.
If each posture teaching posture point P (n) is set to a posture in which mutual interference does not occur, there is very little possibility that mutual interference will occur even in the first section 86 as a whole.

Next, in step S8, the multitask control program 76 is executed. As described above, the multitask control program 76 is composed of the first to fourth subprograms 80a to 80d, and these four subprograms 80a to 80d are simultaneously processed in parallel by the function of the OS 69.

First to fourth subprograms 80a to 80d
Of the processing of the first subprogram 80a of FIG.
This will be described with reference to FIG. The second to fourth subprograms 80b to 80d also perform the same processing as the first subprogram 80a.

First, in step S101, the counter n is initialized to "1".

Next, in step S102, the instruction C
Execute OM21 (n). This command COM21 (n)
Is a move command, the first synchronization control program 7
The command COM21 (n) is transmitted to the servo amplifier 64a, as in the case of 4. The servo amplifier 64a uses the command COM
Command 21 (n) received when 21 (n) is received
Based on this, the operation of each of the articulated robots 14a to 14d is started.

If the command COM21 (n) is a welding command, the command COM21 (n) is sent to the inverter 66a.
(N) is transmitted. The inverter 66a generates a high voltage across the welding electrodes 36a and 36b through the transformer 68a based on the received command COM21 (n) to perform welding.

Next, in step S103, it is confirmed whether or not the moving operation of the articulated robot 14a or the welding work is completed. Wait while moving or welding
If completed, the process moves to the next step S104.

At this time, the first subprogram 80a
Regardless of the states of the second to fourth subprograms 80b to 80d, that is, the states of the articulated robots 14b to 14d, the process proceeds to the next step S104.

Next, in step S104, the instruction C
It is confirmed whether the execution has been completed up to the last instruction of the OM21 (n). If there is an unexecuted instruction, step S10
In 5, the counter n is incremented by "1" and the process returns to step S102. If the execution up to the instruction COM217 has been completed, the next first subprogram 80a is completed,
The procedure moves to step S9 in FIG.

By the way, the first to fourth subprograms 80
Although a to 80d are processed concurrently in parallel by the function of the OS 69, in reality, the CPU 50 divides the processing for each minute time, and the first to fourth subprograms 80a to 80d.
Is executed every minute time. This method is shown in Figure 1.
This will be described with reference to FIG.

At the CPU operating time "1" in FIG.
First, the CPU 50 executes the first subprogram 80a and sends the command COM211 to the servo amplifier 64a.

Similarly, the CPU 50 executes the second to fourth subprograms 80b to 80d at the CPU operating times "2", "3", and "4", and outputs the commands COM211 and C2.
OM231, COM241 servo amplifier 64b ~ 64
Send to d.

Next, at the CPU operating time "5", C
The PU 50 executes the first subprogram 80a. At this time, since the moving operation of the articulated robot 14a has ended, the next command COM212 is transmitted to the inverter 66a.

The CPU operating time "5" is separated from the CPU operating time "3", which is the time when the operation of the articulated robot 14a is completed. During this time, the articulated robot 14a is in the standby state,
Compared to the operation a, the CPU operation time is divided into minute times, so the waiting time is practically zero.

Next, at the CPU operating time "6", C
The PU 50 executes the second subprogram 80b,
At this time, since the articulated robot 14b controlled by the second subprogram 80b is in operation, the second subprogram 80b does not perform substantial processing. Therefore, CP
U50 executes the following third subprogram 80c at this CPU operating time "6". Third subprogram 80
Since the operation of the articulated robot 14c has been completed, c transmits the next command COM232.

Next, at the CPU operating time "7", C
PU50 is the 1st-4th subprogram 80a-80d.
Are sequentially executed, but four articulated robots 14a to 14a
Since d is all in operation, there is no necessary processing.
The CPU 50 stands by at the PU operation time “7”.

As described above, the operating time of the CPU 50 is divided into minute times, and the first to fourth subprograms 80a to 8a are divided.
By sequentially executing 0d, apparently the first to fourth subprograms 80a to 80d are simultaneously processed in parallel.

As shown in the CPU operating time "9", when the articulated robots 14c and 14d end their operations at the same time, the articulated robot 14c is first operated.
To the articulated robot 14d, and the command COM242 to the articulated robot 14d at the next CPU operating time “10”. In this CPU operating time "10", the first to third subprograms 80a to 80
The fourth subprogram 80d may be preferentially executed for c.

Further, the first to fourth subprograms 80a-
80d does not necessarily have to be executed in order, and may include servo amplifiers 64a-64d and inverters 66a-66.
The CPU 50 may select and execute the corresponding first to fourth subprograms 80a to 80d each time a command transmission request from d is received.

As described above, when the articulated robots 14a to 14d are operated by the multitask control program 76, the first to fourth subprograms 80a to 80d operate simultaneously in parallel and independently. It is not affected by the operation status of each other. Therefore, the operation can be completed in a short time.

Further, the second section 88 to which the multitask control program 76 is applied has an adjacent teaching posture point Q.
It is constituted by the welding areas 84a to 84d that collectively set (n). These welding areas 84a to 84d
However, since they respectively correspond to the operations of the articulated robots 14a to 14d, the articulated robots 14a to 14d can perform work in a state where they are appropriately separated from each other.

Further, since the order of the work in the welding areas 84a to 84d is unified in the same direction, the articulated robots 14a to 14d can carry out the work while keeping an appropriate distance. Therefore, even when working on the same opening 44 at the same time, mutual interference is less likely to occur.

Next, the operation of the second synchronization control program 78 will be described. The operation of the second synchronization control program 78 is basically the same as that of the first synchronization control program 74.

In step S9 of FIG. 12, the operation program 72 executes the second synchronization control program 78.

Next, in step S10, the second synchronization control program 78 causes the first to fourth subprograms 8
It is confirmed whether or not all of 0a to 80d are completed. If any one is not finished, the process waits, and if all are finished, the process proceeds to the next step S11.

In step S11, the counter n is initialized to "1".

Next, in step S12, the command CO
Execute M3 (n). This process is the same as step S4.
Is executed in the same manner as the processing of the instruction COM1 (n) in.

Next, in step S13, the robot waits until the operations of the articulated robots 14a to 14d are completed.

Then, in step S14, it is confirmed whether or not the last instruction COM33 of the second synchronization control program 78 has been completed. If there is an unexecuted instruction, step S14 is executed.
After counting up the counter n by "1" in 15, the process returns to step S12. If there is no unexecuted instruction, the process ends.

At this point, each articulated robot 14a-1
4d has returned to the basic posture.

When the articulated robots 14a to 14d are operated by the second synchronization control program 78, the first
Similar to the case of operating by the synchronization control program 74, the mutual interference is less likely to occur.

When operating the articulated robots 14a to 14d by the first and second synchronous control programs 74 and 78, the states of the articulated robots 14a to 14d are changed to the first and second synchronous control programs 74, Since it is centrally managed by 78, it is possible to predict the occurrence of mutual interference, so that the necessary interlock can be set.

When operating the articulated robots 14a to 14d by the multitask control program 76, the articulated robots 14a to 14d are individually controlled by the first to fourth subprograms 80a to 80d.
In this case, the first to fourth subprograms 80a to 80d
It is also possible to provide an information management program capable of exchanging information with each other, and this information management program monitors or predicts mutual interference of the articulated robots 14a to 14d and sets a necessary interlock.

First and second synchronization control program 7
Although 4 and 78 include only the movement command, the welding command may be included if necessary. In this case, the multi-joint robots 14a to 14d can simultaneously perform welding.

Further, in the present embodiment, an example in which the invention is applied to the articulated robots 14a to 14d for welding has been described, but the invention can also be applied to a robot for assembly or painting. The structure of the robot is an articulated robot 14a-1.
It is not necessary to have a 6-axis structure like 4d.

Further, the controller 18 uses one CP
Although the example in which all the control is performed by the U50 has been described, a plurality of CPUs 50 may be provided in the controller 18. In this case, for example, four CPUs 50 are provided, and each CPU 50 is connected to the articulated robots 14a to 14d.
It is advisable to apply them individually to the above, and to operate them in synchronization with each other during synchronization control.

Furthermore, the robot control method and control system according to the present invention are not limited to the above-described embodiments, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention. .

[0125]

As described above, according to the robot control method and control system of the present invention, mutual interference between robots is prevented when a plurality of robots operate in close proximity to each other. In addition, the effect that the operation time can be shortened is achieved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a robot control system according to the present embodiment.

FIG. 2 is an explanatory diagram showing an articulated robot.

FIG. 3 is an explanatory diagram showing a state in which an articulated robot welds a vehicle body.

FIG. 4 is a block diagram showing a configuration of a controller.

FIG. 5 is a table showing a path table.

FIG. 6 is an explanatory diagram showing first, second and third sections.

FIG. 7 is an explanatory diagram showing a welding region.

FIG. 8 is a block diagram showing a configuration of a first synchronization control program.

FIG. 9 is a block diagram showing a configuration of a multitask control program.

FIG. 10 is a block diagram showing a configuration of a second synchronization control program.

11A is a schematic time chart of synchronous control, and FIG. 11B is a schematic time chart of multitask control.

FIG. 12 is a flowchart showing a procedure of a robot control method according to the present embodiment.

FIG. 13 is a time chart of synchronization control in the present embodiment.

FIG. 14 is a flowchart showing processing of a first subprogram.

FIG. 15 is a time chart of multitask control according to the present embodiment.

[Explanation of symbols]

10 ... Robot control system 14a-14d ...
Articulated robot 18 ... Controller 40 ... Car body 42 ... Manufacturing line 44 ... Opening 50 ... CPUs 64a to 64d ...
Servo amplifiers 66a to 66d ... Inverter 69 ... OS 70 ... Path table 72 ... Operation program 80a-80d ... Subprogram 84a-84d ...
Welding areas 86, 88, 90 ... Section

Continued front page    (72) Inventor Yasuhiro Kawai             1-10-1 Shinsayama, Sayama City, Saitama Prefecture             Engineering Co., Ltd. (72) Inventor Eisaku Hasegawa             1-10-1 Shinsayama, Sayama City, Saitama Prefecture             Engineering Co., Ltd. (72) Inventor Toshiyuki Kondo             1-10-1 Shinsayama, Sayama City, Saitama Prefecture             Engineering Co., Ltd. F-term (reference) 3C007 AS11 BS12 BT08 CV06 CW02                       JS02 LV15 MS09 MT02                 4E065 AA05

Claims (5)

[Claims] 1. A robot control method for controlling a plurality of robots performing a predetermined work on a work by a controller, wherein an operation path of each robot is divided into a plurality of sections, and multitask control is performed for each section. A method for controlling a robot, characterized in that the robots are controlled separately for synchronous control. 2. The robot control method according to claim 1, wherein the section starts from the basic posture of each robot and reaches a vicinity of the workpiece, and the end of the first section. It is composed of a second section starting from a point and performing a predetermined work on the work, and a third section starting from the end point of the second section and reaching a retracting posture for retracting from the work. A robot control method characterized by the above. 3. The robot control method according to claim 2, wherein each of the robots is controlled by the synchronous control in the first section and the third section, and the multitask is performed in the second section. A method for controlling a robot, characterized in that each of the robots is controlled by control. 4. The robot control method according to claim 1, wherein work points for performing a predetermined work on the work are arranged in an annular shape, and the work section is the second section. A work point is assigned to each of the robots, and the work points assigned to the second section of each of the robots are set so that work is performed in the same rotation direction. Characteristic robot control method. 5. A robot control system for controlling a plurality of robots performing a predetermined work on a work by a controller, and a synchronization control unit for synchronously controlling the robots, and controlling the robots by multitask control. And a multi-task control unit, wherein the motion path of each robot is divided into a plurality of sections, and the synchronous control section or the multi-task control section is applied to each section. system.