JP2003285287A - Robot control method, control unit and controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To synchronously control a plurality of robots accurately. <P>SOLUTION: The robot controller 20 has computers 20a and 20b controlling each of robots 1a and 1b, connected with each other via a serial cable 2. The computers 20a and 20b incorporate control units 10a and 10b for controlling the respective robots 1a and 1b. The control unit 10a includes a movement information supply part 11 for supplying traveling time of the robot 1a reaching the next teaching point to the control unit 10b at least once during a process in which the robots 1a and 1b travel between two adjacent teaching points. The control unit 10b includes a speed regulating part 12 for regulating the speed of the robot 1b based on the traveling time of the robot 1a so that the robots 1a and 1b simultaneously arrive at the next teaching point. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method and apparatus for driving a plurality of robots while synchronizing them.

[0002]

2. Description of the Related Art For example, when arc welding of a horizontal fillet joint is performed from both sides, a plurality of industrial robots may cooperate to perform a working operation. When a plurality of robots collaborate in this way, it is necessary to perform synchronous control in order to prevent them from colliding with each other and to improve work efficiency.

As a technique for operating a plurality of industrial robots while synchronously controlling them, for example, Japanese Patent Laid-Open No. 5-27815 discloses a technique for synchronously controlling one of the plurality of robots as a master and the other robot as a slave. Has been done. The technique according to this publication is a so-called PTP (point-to-point) type in which a plurality of points (hereinafter referred to as teaching points) are defined along a work path of a robot, and synchronous control is performed at each teaching point. Specifically, first, the master starts moving, and when the master instructs the slave to move time to the next teaching point, the slave receives the instruction of the master and arrives at the next teaching point at the same time. The speed is adjusted to.

[0004]

In the actual operation process of the robot, the speed and the position may change during the movement of the robot. This may of course be done by human operation, but in the case of a robot that performs arc welding, it may also be performed by feedback control from an external sensor such as arc copying or a visual sensor. If the speed or the position is changed between teaching points in this way, the synchronous control technique according to the above publication cannot deal with it. Specifically, even if the master instructs the slave to move to the next teaching point at a certain teaching point, if the speed or position is changed before the master reaches the next teaching point, the master The robot arrives at the next teaching point at a time different from the time previously instructed by itself.
That is, it is impossible in principle to synchronize the master and slave.

In addition, when a processing tool such as a welding torch or hand is provided at the tip of the robot, the processing tool is actually turned ON after an ON command is issued to the processing tool.
There is some waiting time until it becomes, and there is some variation in the waiting time. For example, in the case of an arc welding robot having a welding torch at the tip as a processing tool, the time from when an ON command is issued to the welding torch until arc discharge occurs in the welding torch and welding current flows , Welding wire condition, welding power source characteristics, etc. As described above, a robot including a processing tool that requires a waiting time is generally in a stopped state until the processing tool is turned on, and then starts moving after confirming that the processing tool is turned on. Therefore, even if the ON commands are simultaneously issued to the respective processing tools, if the waiting times are different, the robots cannot be simultaneously started to move. If each of the master and slave has a processing tool that requires a wait time, and the processing tool of the slave is turned on before the master, the slave will stop the processing tool while it is on and issue a command from the master. have to wait. For example, in an arc welding robot that has a welding torch at the tip as a processing tool, the slave welding torch may be in a stopped state with an arc, and excessive heat input or beads may be formed at that stop position, resulting in a defect. There is.

On the other hand, regarding communication means between robots,
When hardware that can control multiple robots with one unit is used, high-speed communication via the bus can be performed by connecting the units to each other via a bus with high information transfer performance inside the hardware. it can. At this time, the time required for communication (communication delay time) is several microseconds or less, which is sufficiently smaller than the robot control cycle (several m to several tens msec) and can be ignored. However, a conventional communication means has been to connect a control device capable of controlling only one device to each robot and connect each control device with a communication medium such as a serial cable. A communication medium such as a serial cable used at this time has lower information transfer performance than the above-mentioned bus, and its communication delay time is about several tens to several hundreds ms, which can be ignored for the robot control cycle. Not a thing. After the instruction is given from the master until the instruction arrives at the slave, it is delayed by the communication delay time, and as a result, the synchronization between the robots is also delayed by ΔTcom.

An object of the present invention is to provide a robot control method, a control unit and a control device for accurately synchronizing a plurality of robots.

Another object of the present invention is to provide a robot control method, a control unit, and a control device capable of reducing the problem of work defects.

Another object of the present invention is to provide a robot control method, a control unit and a control device capable of accurately synchronizing a plurality of robots even if a communication delay occurs.

[0010]

In order to achieve the above object, a robot control method according to a first aspect of the invention is such that a movement path connecting a plurality of teaching points provided for each robot is controlled by an independent control unit. In the robot control method for controlling each robot so that the plurality of robots move synchronously, one of the plurality of robots is at least once in the process of the plurality of robots moving between two adjacent teaching points. Movement information supplying step of supplying one movement information from the control unit of the robot to the control units of the remaining robots, and moving the speeds of the remaining robots so that all the robots reach the next teaching point at the same time. And a speed adjusting step for adjusting based on the information.

A robot control unit according to a fifth aspect of the present invention controls each robot so that the plurality of robots synchronously move along a movement path connecting a plurality of teaching points provided for each robot. Control unit for supplying the robot movement information related to the control of the control unit to the control units of the remaining robots at least once in the process in which the plurality of robots move between two adjacent teaching points. It is characterized in that it comprises a moving information supply means.

A robot control unit according to a seventh aspect of the present invention controls each robot such that the plurality of robots synchronously move on a movement path connecting a plurality of teaching points provided for each robot, the robots independent of each other. Control unit of the above, at least once in the process in which the plurality of robots move between two adjacent teaching points, all of the robots move to the next teaching point based on the movement information supplied from another control unit. So as to arrive at the same time at the same time, a speed adjusting means for adjusting the speed of the robot under the control of the control unit is provided.

A robot controller according to a tenth aspect of the present invention is a robot controller for controlling each robot so that the plurality of robots synchronously move along a movement path connecting a plurality of teaching points provided for each robot. Of the robot, the movement information output means for outputting movement information of one of the plurality of robots, and the movement information output means output the movement information at least once in the process of moving between the two adjacent teaching points. Speed adjusting means for adjusting the speeds of the remaining robots so that all of the robots arrive at the next teaching point at the same time based on the movement information.

According to the above configuration, even if the speed or movement path of the robot is changed between teaching points, the movement information of a certain robot is supplied to the remaining robots by the time the robot reaches the next teaching point. By adjusting the speeds of the remaining robots based on the information, it is possible to control the plurality of robots to arrive at the next teaching point at the same time. Conventionally, the movement information is supplied and the speed is adjusted only at each teaching point, but by performing such an adjustment between the teaching points, it is possible to change the robot speed or the moving route between the teaching points. Can respond. That is, a plurality of robots can be accurately synchronized even if the speed or movement route of the robot is changed during movement.

According to a second aspect of the present invention, in the robot control method according to the first aspect, the movement information of one of the plurality of robots is shorter than the time required for the robot to move between two adjacent teaching points. It is characterized by supplying in a cycle.

According to a sixth aspect of the present invention, in the robot control unit according to the fifth aspect, the movement information of the robot relating to the control of the control unit is calculated based on a time required for the robot to move between two adjacent teaching points. It is also characterized by supplying in a short cycle.

According to a tenth aspect of the present invention, in the robot control apparatus according to the tenth aspect, the movement information output means moves the movement information of one of the plurality of robots between two teaching points adjacent to the robot. The output is performed in a cycle shorter than the time required for the.

According to the above structure, the movement information is supplied between the two adjacent teaching points at least once and at regular intervals to synchronously control the movement of the robot, thereby realizing more accurate synchronous control. .

According to a third aspect of the present invention, in the robot control method according to the first or second aspect, the robot at each teaching point is moved toward the next teaching point without waiting for an instruction from another robot. Is characterized by.

According to a seventh aspect of the present invention, in the control unit of the robot according to the seventh aspect, the robot at each teaching point is started to move toward the next teaching point without waiting for an instruction from another robot. Characterize.

A robot controller according to a twelfth aspect of the present invention, in the tenth or eleventh aspect, starts the movement of the robot at each teaching point toward the next teaching point without waiting for an instruction from another robot. Is characterized by.

According to the above configuration, since each robot continues its movement without stopping without waiting for an instruction from another robot, when they are equipped with a work tool with a waiting time, the work tool is turned on. The problem of being stopped as it is and causing a work defect is reduced.

According to a fourth aspect of the present invention, in the robot control method according to any one of the first to third aspects, in the speed adjusting step, adjustment is performed in consideration of communication delay between the control units. .

According to a ninth aspect of the present invention, there is provided the robot control unit according to the seventh or eighth aspect, wherein the speed adjusting means makes an adjustment in consideration of a communication delay between the control units.

According to a thirteenth aspect of the present invention, in the robot control apparatus according to any one of the tenth to twelfth aspects, the speed adjusting means performs an adjustment in consideration of a communication delay between the control units. .

According to the above configuration, the communication delay is taken into consideration when adjusting the speed of the robot, so that there is a communication delay that cannot be ignored with respect to the robot control cycle due to a communication medium such as a serial cable having a relatively low information transfer performance. Even if it occurs, it is possible to accurately control the synchronization.

A robot controller according to a fourteenth aspect is the robot controller according to any one of the tenth to thirteenth aspects, wherein the controller includes a plurality of independent control units for each robot, and each control unit has the movement information. It is characterized by having both an output means and the speed adjusting means.

According to the above configuration, each control unit has both movement information output means and speed adjustment means,
The movement information of each robot can be exchanged and the speed thereof can be adjusted based on the movement information, the master-slave relationship between masters and slaves is eliminated between the robots, and highly flexible synchronous control is realized.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the arrangement of a robot controller according to an embodiment of the present invention. Figure 2
It is a schematic diagram which shows a part of movement path in each robot of FIG. FIG. 3 is a flowchart showing the operation from the start of movement of each robot in FIG. 1 to the second teaching point along the time axis. FIG. 4 is a flowchart showing a process executed by the robot control device according to the embodiment of the present invention. FIG. 5 is a block diagram showing the configuration of a robot control apparatus according to another embodiment of the present invention.

First, with reference to FIG. 1, a schematic configuration of a robot controller according to an embodiment of the present invention will be described.
The two robots 1a and 1b shown in FIG. 1 are for arc welding the horizontal fillet joint 5 of the metal plate from both sides. The robot controller 20 shown in FIG. 1 is one in which two computers 20a and 20b for controlling the two robots 1a and 1b are connected to each other via a serial cable 2 as a communication means. . The computer 20a, 20b has a CPU
Hardware such as 15, a memory 16, a hard disk (not shown), an FD or CD drive device, and control units 10a and 10b for controlling the robots 1a and 1b are housed. The control unit 10a of the robot 1a is provided with a movement information supply unit 11 for supplying the movement time of the robot 1a, while the control unit 10b of the robot 1b is provided with a speed adjustment unit for adjusting the speed of the robot 1b. 12 are provided. The movement information supply unit 11 provided in the control unit 10a of the robot 1a determines the movement time of the robot 1a at least once during the movement of the robots 1a and 1b between two adjacent teaching points. It is supplied to 10b. Further, the speed adjustment unit 12 provided in the control unit 10b of the robot 1b uses the movement information supply unit 11 so that the two robots 1a and 1b arrive at the next teaching point at the same time.
The speed of the robot 1b is adjusted based on the movement time of the robot 1a supplied from the robot. Furthermore,
The robot 1a and the robot 1b each have a power source (not shown).

Next, with reference to FIGS. 2 to 4, the processing executed by the robot controller 20 according to the present embodiment will be described. FIG. 4 shows the process of controlling the robot from the start point to the end point of the movement route, but FIGS. 2 and 3 show the second teaching point from the movement start point of the robot 1a and the robot 1b of FIG. It only shows up to. Pa0 and Pb0 shown in FIG. 2 are movement start points of the robots 1a and 1b. The two robots 1a and 1b arrive at the first teaching points Pa1 and Pb1 almost at the same time after leaving the movement start points Pa0 and Pb0, respectively, and are further position-corrected to Pa1 'and Pb.
It moves to 1 ', and then heads to the next teaching point Pa2, Pb2. Thus, for the robot 1a, Pa1,
Pa2, Pb1, Pb2, etc. for the robot 1b,
A plurality of teaching points are provided on the moving paths of the robot 1a and the robot 1b, respectively. Two robots 1a, 1
The control device 20 including the control units 10a and 10b shown in FIG. 1 functions so that b moves synchronously and arrives at each of these teaching points at the same time.

First, the two robots 1a and 1b are shown in FIG.
As shown in, the movement starts at the movement start points Pa0 and Pb0 almost at the same time (S1, see FIG. 4), and the first teaching points Pa1 and Pb1 arrive at almost the same time (S2). The time at this time is set as t = 0 (see FIG. 3). The two robots 1a and 1b have first teaching points Pa1 and Pb1 respectively.
At the same time as arriving at, each control unit 10a shown in FIG.
In response to the command from 10b, the position correction operation is started (S3). Here, the teaching points Pa1 and Pb1 are before correction, and the accurate position of the welding joint is a point Pa slightly apart.
1 ', Pb1'.

In performing the position correction, the external sensor such as a contact performs an accurate teaching point search operation. here,
Since the time required for the search operation depends on the work installation error, the search method, etc., each robot 1a, 1b departs from the uncorrected teaching point Pa1, Pb1 and then the corrected teaching point Pa.
The time required to reach 1'and Pb1 'is different.
In FIG. 3, the robot 1a arrives at the corrected teaching points Pa1 'and Pb1' at time t = Ta1 and the robot 1b at time t = Tb1 (Tb1 ≠ Ta1), respectively (S4).

Each robot 1a, 1b has a corrected teaching point P
At the same time as arriving at a1 'and Pb1' (S4), a command to turn on the arc welding processing tool provided in each of the robots 1a and 1b is issued from each control unit 10a, 10b (S5), and a power source (not shown) is supplied. Sent. Each robot 1a, 1b remains stopped at the teaching points Pa1 ', Pb1' until the arc is generated from the arc welding tool (S6). Stopping until the occurrence of this arc is called "waiting". Here, the time required from when an ON command is issued to the arc welding tool to when the arc is actually generated and the waiting is released depends on the characteristics of the robots 1a and 1b. In the present embodiment, as shown in FIG. 3, the robot 1a has an arc at time t = Ta2 and the robot 1b has an arc at time t = Tb2, and the waiting time is released. Is different from (Ta2-Ta1) for the robot 1a and (Tb2-Tb1,) for the robot 1b.

Each of the robots 1a and 1b starts moving toward the next teaching point Pa2, Pb2 at the same time when the arc is generated from the processing tool (S6) and the waiting state is released (S6).
7). As shown in FIG. 3, Ta2 is used in this embodiment.
Since> Tb2, the robot 1b starts moving toward the next teaching point first. That is, the robot 1b
Starts moving toward the next teaching point without waiting for an instruction from the robot 1a (S7).

The control unit 1 of the robot 1a shown in FIG.
0a indicates that the robot 1a is moved to the next teaching point P at time t = Ta2.
At the same time when the robot 1a starts to move toward a2, the next teaching point Pa from the position at that time as the movement information of the robot 1a.
The moving time of the robot 1a until reaching 2 is supplied to the control unit 10b of the robot 1b via the serial cable 2 of FIG. 1 (S8). The supply of the movement information is executed by the movement information supply unit 11 included in the control unit 10a of the robot 1a shown in FIG. 1, and at this time, the time in the control unit 10a is reset to t = 0. It should be noted that in the present embodiment, as described in detail later, the supply of the movement information is performed at every constant cycle Tcyc shorter than the time required for the robots 1a and 1b to move between two adjacent teaching points. .

The control unit 10b of the robot 1b which has received the movement information adjusts the speed of the robot 1b based on the movement time of the robot 1a so that the robot 1a and the robot 1b arrive at the next teaching point at the same time (S9). ).
This speed adjustment is executed by the speed adjusting unit 12 included in the control unit 10b of the robot 1b shown in FIG. Here, the time required for communication of information from the control unit 10a of the robot 1a to the control unit 10b of the robot 1b (communication delay time) is ΔTcom. The communication delay time ΔTcom is due to the serial cable 2 being interposed between the control units 10a and 10b as shown in FIG.

The speed adjustment of the robot 1b by the control unit 10b is performed as follows. First, the robot 1
Regarding the moving time Tma from the point located at that time in a to the next teaching point Pa2, the communication delay time Δ
Correction is performed by the following equation (1) in consideration of Tcom, and the corrected moving time Tma ′ of the robot 1a is obtained. next,
Using the corrected moving time Tma ′ of the robot 1a obtained by the above formula (1), the moving time from the point where the robot 1b is located when the moving information is received to the next teaching point Pb2 is Tmb, and the following formula ( Robot 1 after correction from 2)
The moving time Tmb 'of b is calculated. The speed of the robot 1b is changed based on the moving time Tmb 'thus obtained. Tma ′ = (Tma−ΔTcom) (1) Tmb ′ = Tmb + Gain × (Tma′−Tmb) (2) Here, Gain: control gain (≦ 1.0)

The movement time T of each robot 1a, 1b
The greater the difference between ma and Tmb, the greater the change in the robot speed when performing the above process.
By reducing the control gain Gain in (1), it is possible to prevent a rapid speed change and smoothly change the speed.

As shown in FIG. 3, the time at which the movement information supply unit 11 included in the control unit 10a of the robot 1a transmits movement information to the control unit 10b of the robot 1b is t = 0 (S8, see FIG. 4). , At time t = ΔTcom, the speed of the robot 1b is adjusted (S9).
After that, the time t has not reached Tcyc (t <Tcyc)
It is determined whether or not (S10). When the time t has not reached Tcyc (t <Tcyc) (S10; YES)
Further checks whether or not the robot 1a has arrived at the next teaching point (S11). When the robot 1a has not arrived at the next teaching point (S11; NO), each robot 1a,
1b keeps moving at each speed until time t reaches Tcyc. When the time t reaches Tcyc (t = Tcyc) (S10; NO), the movement information of the robot 1a is supplied again (S8), and the speed of the robot 1b is adjusted (S9).

By repeating the above-described processing (S8, S9) every fixed period Tcyc, as shown in FIG.
Each of the robots 1a and 1b can reach the next teaching point almost at the same time. When the robot 1a and the robot 1b arrive at the next teaching point almost at the same time (S11;
YES), it is determined whether or not the arrived teaching point is the final teaching point on the moving route (S12). When the arrived teaching point is not the final one (S12; NO), the robots 1a and 1b start moving to the next teaching point without stopping (S7). On the other hand, when the arrived teaching point is the final one (S12; YES), the control is finished.

As described above, the control device 20 for a robot according to this embodiment has two robots 1a and 1b.
The moving time of the robot 1a is
Is provided with a movement information supply unit 11 that supplies the control unit 10b of another robot 1b at least once in the process of moving between two adjacent teaching points. Furthermore, a speed adjusting unit 12 that adjusts the speed of the robot 1b based on the moving time supplied by the moving information supplying unit 11 so that the two robots 1a and 1b arrive at the next teaching point at the same time. I have it. As a result, even if the speeds and movement paths of the robots 1a and 1b are changed between teaching points, the movement time of a robot is supplied to the remaining robots until the robots 1a and 1b reach the next teaching point. By adjusting the speeds of the remaining robots based on the information, it is possible to control so that a plurality of robots arrive at the next teaching point at the same time. That is, a plurality of robots can be accurately synchronized even if the speed or movement route of the robot is changed during movement.

Further, in the present embodiment, the supply of the moving time for the robot 1a (S8) is supplied for each constant period Tcyc shorter than the time required for the robots 1a and 1b to move between two adjacent teaching points. is doing. In this way, the moving time is supplied between two adjacent teaching points at least once and at regular intervals Tcyc, and the robots 1a, 1
By synchronously controlling the movement of b, more accurate synchronous control is realized.

In this embodiment, the robot 1b starts moving toward the next teaching point without waiting for the instruction from the robot 1a in step S7. In this way, the robots 1a and 1b arriving at each teaching point start moving toward the next teaching point without waiting for instructions from other robots, respectively, so that they are accompanied by waiting time. In the case of the above, it is possible to reduce the problem that the processing tool is stopped while being turned on to cause a work defect.

Further, the speed adjustment unit 12 causes the communication delay ΔT between the control units 10a and 10b in step S9.
com is adjusted. In this way, by considering the communication delay ΔTcom when adjusting the speed of the robot,
Even if a communication delay ΔTcom that cannot be ignored with respect to the control cycle of the robot occurs due to the communication medium such as the serial cable 2 having a relatively low information transfer performance, the synchronization control can be performed accurately.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes are possible within the scope of the claims. . For example, as shown in FIG. 5, a unit common to the robots 1a and 1b may be provided. Then, in the unit, the control unit 10a of the robot 1a, the control unit 10b of the robot 1b, the CP
The U15, the memory 16 and the like may be provided and the respective units may be connected to each other by the internal bus 22. That is, even if high-speed communication is performed by using hardware (common unit) capable of controlling a plurality of robots by one unit, and connecting each unit to each other by a bus 22 having high information transfer performance inside the hardware. Good.

Further, in the present embodiment, the control device 20 has the independent control units 20a, 2 for the robots 1a, 1b.
0b, the control unit 10a of the robot 1a includes a movement information supply unit 11, and the control unit 10b of the robot 1b includes a speed adjustment unit 12, but the control units 10a and 10b independent of each robot include the movement information supply unit 11. You may have both 11 and the speed adjustment part 12. Since each control unit 10a, 10b has both the movement information supply unit 11 and the speed adjustment unit 12, each robot 1a, 1b
The movement information can be exchanged and the speed thereof can be adjusted based on the movement information, the master-slave relationship between the robots 1a and 1b, that is, the master and the slave, is eliminated, and a highly flexible synchronous control is realized.

Further, in the present embodiment, the movement time relating to the robot 1a is supplied for each fixed cycle Tcyc which is shorter than the time required for the robots 1a and 1b to move between two adjacent teaching points. The present invention is not limited to this, and the robots 1a and 1b may be supplied at least once in the process of moving between two adjacent teaching points.

Further, in this embodiment, the movement information supply unit 1
Although the movement information of the robot 1a supplied by 1 is the movement time, it may be the movement speed.

Further, in this embodiment, the robots 1a and 1b which have arrived at the respective teaching points are designed to start moving toward the next teaching point without waiting for instructions from other robots. The movement does not have to be started until there is an instruction from the robot. However, if the robot is equipped with a work tool with a waiting time, and if the work tool is stopped while it is ON without starting movement until there is an instruction from another robot, excessive heat input or beads may occur at that stop position. It may be formed and become a defect. Therefore, in order to mitigate the problem of causing work defects when the robot is equipped with a work tool with a waiting time, aim each robot at the next teaching point without waiting for instructions from other robots. It is preferable to start the movement.

Further, in the present embodiment, in the speed adjusting step (S9), the communication delay ΔTcom between the control units 10a and 10b is taken into consideration, and the above equations (1),
Although the adjustment according to (2) is performed, the present invention is not limited to this. For example, as shown in FIG. 5 described above, when a common unit in which each unit including the control units 10a and 10b for the robots 1a and 1b is connected by the bus 22 having high information transfer performance is used, the communication delay ΔTcom is not considered. The movement information may be supplied without correction. This can be applied when high-speed communication is performed between the control units 10a and 10b by the internal bus 22, but as shown in FIG. 1, information is transferred between the control units independent of each of the plurality of robots like a serial cable 2. When connecting by a communication medium having a relatively low performance, it is preferable to adjust the speed in consideration of the communication delay ΔTcom.

Further, although the serial cable 2 is used as the communication medium for connecting the control units 10a and 10b independent to the robots 1a and 1b in this embodiment, other communication mediums may be used.

Furthermore, in the present embodiment, each robot 1a, 1b arrives at the first teaching point Pa0, Pb0 (before correction), and then the position is corrected to correct the teaching point Pa.
It has arrived at 0 ', Pb0', but is not limited to this. For example, if each robot 1a, 1b is made to reach the first teaching point with an accuracy that does not require position correction,
Position correction is not performed, that is, steps S2 and S3 shown in FIG.
May be omitted and step S5 for issuing an ON command to the arc welding tool may be performed. Further, the position correction may be performed each time the robots 1a and 1b arrive at each teaching point. In addition, when using a robot without a processing tool, step S
1 to S6 may be omitted and control may be performed in steps S7 to S12.

[0055]

Since the present invention is configured as described above, it has the following effects.

According to the first, fifth, seventh and tenth aspects, the plurality of robots can be accurately synchronized even if the speed or the movement route of the robot is changed during the movement.

According to the second, sixth and eleventh aspects, more accurate synchronization control is realized.

Further, according to the third, eighth and twelfth aspects, when the robot is provided with a working tool with a waiting time, the problem that the working tool is stopped while ON and causes a work defect is mitigated. It

Further, according to claims 4, 9 and 13, even if a communication delay that cannot be ignored with respect to the control cycle of the robot occurs, the synchronous control can be accurately performed.

Further, according to the fourteenth aspect, the master-slave relationship between the robot and the master and the slave is eliminated, and a highly flexible synchronous control is realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control device for a robot according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a part of a movement path in each robot of FIG.

FIG. 3 is a flowchart showing an operation along a time axis from the start of movement of each robot of FIG. 1 to reaching a second teaching point.

FIG. 4 is a flowchart showing processing executed by a robot control device according to an embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a robot control device according to another embodiment of the present invention.

[Explanation of symbols]

1a, 1b Robot 2 Serial cable (communication means) 5 Horizontal fillet joint 10a, 10b of metal plate Control unit 11 Movement information supply section (movement information supply means, movement information output means) 12 Speed adjustment section (speed adjustment means) 22 Internal bus 20,30 Control device

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Claims (14)

[Claims] 1. A robot control method for controlling each robot so that the plurality of robots controlled by an independent control unit move synchronously on a movement path connecting a plurality of teaching points provided for each robot, At least once in the process in which the plurality of robots move between two adjacent teaching points, one of the plurality of robots
Movement information supplying step of supplying one movement information from the control unit of the robot to the control units of the remaining robots, and moving the speeds of the remaining robots so that all the robots arrive at the next teaching point at the same time. And a speed adjusting step for adjusting based on information. 2. The movement information of one of the plurality of robots is supplied in a cycle shorter than the time required for the robot to move between two adjacent teaching points. A method for controlling the described robot. 3. The robot control according to claim 1, wherein the robot at each teaching point is started to move toward the next teaching point without waiting for an instruction from another robot. Method. 4. The robot control method according to claim 1, wherein in the speed adjusting step, adjustment is performed in consideration of communication delay between the control units. 5. A robot control unit independent of each robot, which controls each robot so that the plurality of robots synchronously move along a movement path connecting a plurality of teaching points provided for each robot, The robot is provided with movement information supply means for supplying movement information of the robot related to control of the control unit to the control units of the remaining robots at least once in the process of moving between two adjacent teaching points. A robot control unit characterized by the above. 6. The movement information of the robot under the control of the control unit is supplied in a cycle shorter than the time required for the robot to move between two adjacent teaching points. 5. The robot control unit according to item 5. 7. A robot control unit independent of each robot, which controls each robot so that the plurality of robots synchronously move along a movement path connecting a plurality of teaching points provided for each robot, Based on the movement information supplied from another control unit at least once in the process of the robot moving between two adjacent teaching points, all the robots arrive at the next teaching point at the same time. A control unit for a robot, comprising a speed adjusting means for adjusting the speed of the robot according to the control of the control unit. 8. The robot control unit according to claim 7, wherein the robot at each teaching point is started to move toward the next teaching point without waiting for an instruction from another robot. . 9. The control unit of the robot according to claim 7, wherein the speed adjusting means performs adjustment in consideration of a communication delay between the control units. 10. A robot control device for controlling each robot so that the plurality of robots synchronously move along a movement path connecting a plurality of teaching points provided for each robot. At least once in the process of moving between teaching points, one of the plurality of robots
Based on the movement information output means for outputting one movement information, and the movement information output by the movement information output means, all the robots of the remaining robots arrive at the next teaching point at the same time. A control device for a robot, comprising: speed adjusting means for adjusting the speed. 11. The movement information output means outputs movement information of one of the plurality of robots at a cycle shorter than a time required for the robot to move between two adjacent teaching points. The control device for a robot according to claim 10, wherein the control device is a robot. 12. The robot control according to claim 10, wherein the robot at each teaching point is started to move toward the next teaching point without waiting for an instruction from another robot. apparatus. 13. The control device for a robot according to claim 10, wherein the speed adjusting unit makes an adjustment in consideration of a communication delay between the control units. 14. The control device includes a plurality of control units independent for each robot, and each control unit has both the movement information output means and the speed adjustment means. Item 14. The control device for a robot according to any one of items 10 to 13.