JPH07136975A - Multiple robot system - Google Patents

Abstract

(57) [Abstract] [Purpose] The objective is to reduce the operator's burden on avoiding deadlocks among multiple robots and to completely eliminate deadlocks between robots. A control device for controlling a plurality of robots stores a work program for each robot, stores work execution means 11 for sequentially executing the work program, and a work state indicating whether each robot is working or not, Retracting determination means 12 for determining whether or not to retract the inside robot to a safe position, and trajectory control means 13 for retracting the robot to the safe position by performing trajectory calculation and interference check of each robot. And a position control means 14 for generating a motor drive signal for each robot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-robot system composed of a plurality of robots and a controller for controlling them.

[0002]

2. Description of the Related Art Recently, in the use of industrial robots,
For the purpose of shortening work tact and collaborative work, a plurality of robot systems are operated so that the operation areas of the respective robots overlap. In such a system, there is a problem that the robots interfere with each other in the overlapping part of the operation area, and the tasks performed by the robots have a predetermined order relation of the tasks. In some cases, the control method becomes complicated. In the case where the order relation of the work of each robot is defined, the simplest method is to evacuate the robot to the safe position after the work of a certain robot is completed, and then start the robot for the next work. However, this method has a problem that the waiting time of the robots becomes long and the total work tact becomes long. Therefore, various methods for advancing the work while avoiding the interference between the robots have been devised.

Japanese Laid-Open Patent Publication No. 64-36307 discloses a computer connected to a robot controller.
A method for managing and controlling areas where robots collide with each other is described.

Japanese Patent Laid-Open No. 2-190291 has means for declaring that each robot enters and leaves the interference area, and when one robot is in the interference area, the other robot waits outside the interference area. The method of making is described.

In Japanese Patent Laid-Open No. 2-83196, the controller of each robot is provided with collision avoidance means, and the presence or absence of a collision risk is detected from the geometrical positional relationship between the self arm and the other arm to detect the danger. There is described a method of determining a priority right from each other's operation state at a certain time and generating a collision avoidance path when there is no priority right.

[0006]

However, even if the interference between the robots can be avoided by these interference avoiding methods, a new problem that the deadlock between the robots as described below cannot be avoided occurs. To do.

In the first example, two robots A and B are
In the case of asynchronously performing work that does not have a sequence relation with the work of the other party, robot A wants to move to the work place, but robot B cannot move because it is stopped in the vicinity, while robot B does work. It is a deadlock, such as waiting for the next command at the end of.

In the second example, two robots A and B are
In the case of performing a work in which the order relationship with the work of the other party is determined, the robot A wants to move to the work place, but the robot B cannot move because the robot B is stopped near the work place.
The robot B has a deadlock in which the work of the robot A is not completed and thus the permission to continue the work cannot be obtained.

In order to avoid such a deadlock, in the former case, after the work of the robot B is completed, it is necessary to program the operation of retracting to a position where interference does not occur. In the latter case, it is necessary to program the description of the interlock so that the robot B does not go near the work place until the work of the robot A is completed.

However, it is difficult to take all the above-mentioned cases of deadlock occurrence into consideration at the teaching stage, and the operator's burden is heavy.

The present invention solves the above-mentioned conventional problems, and an object thereof is to reduce the burden on the operator for avoiding deadlock of a plurality of robots and to completely eliminate the deadlock between robots.

[0012]

In order to achieve this object, a multi-robot system according to claim 1 of the present invention comprises a plurality of robots and a controller for controlling them. The work program of each robot is stored, the work executing means for sequentially executing the work program, and the work state of whether each robot is working or not working are stored, and the work executing means communicates with the work executing means. Evacuation judgment means for updating the work status and judging whether to retract the non-working robot to a safe position based on the work status, and trajectory calculation of each robot and interference check by communicating with the work execution means. In the event of interference, the trajectory control means for retracting the robot to a safe position by communicating with the evacuation determination means and the trajectory control means are communicated. It is characterized by having more configured robot save circuit position control means for generating a motor drive signal for each robot.

Further, a multi-robot system according to a second aspect of the present invention comprises a plurality of robots and one control device for controlling them, and the control device is a work indicating the order relation of the work performed by each robot. Work sequence setting means for setting sequence data, work sequence storing means for storing the work sequence data set by the work sequence setting means, work programs for each robot are stored, and the programs are sequentially executed. The work progressing means for each robot and the work progressing status of each robot are stored, the work progressing status is updated by communicating with the work performing means, and the work order waiting state is waited based on the work ordering data and the work progressing status. Determine whether to retract the robot to a safe position,
When it is determined that the robots are to be evacuated, the robots wait for the robots to return to their original positions and determine whether or not the work can be continued based on the work progress status, and the robots by communicating with the work execution means. The locus calculation and interference check are performed, and if interference occurs, communication is made with the evacuation determination means to save the current position of the robot as a return position, and then retract the robot to a safe position and retract it. It is characterized by having a robot retract circuit with a return operation, which is composed of a trajectory control means for returning the robot to the return position and a position control means for communicating with the trajectory control means to generate a motor drive signal for each robot. .

Further, a multi-robot system according to a third aspect of the present invention comprises a plurality of robots and one control device for controlling them, and this control device has a work sequence indicating a sequence relation of work to be executed by each robot. Work order setting means for setting data, work order storing means for storing the work order data set by the work order setting means, work programs for each robot are stored, and the programs are sequentially executed. A work execution means, a work status and a work progress status of each robot are stored, the work status and the work progress status are updated by communicating with the work execution means, and the work status, the work sequence data, and the work status data are stored. Based on the work progress status, it is judged whether the robot not in work or the robot waiting for work order is retracted to the safe position, If it is determined to evacuate the robot, the robot waits for the robot to return to its original position and communicates with the evacuation determining means that determines whether or not the operation can be continued based on the work progress status. By calculating the trajectory of each robot and checking the interference, and if interference occurs, it communicates with the evacuation judgment means to save the current position of the robot as a return position and then retract the robot to a safe position for work. A robot with a returning operation, which is composed of a locus control means for returning the robot waiting in the order to the returning position when the robot is retreated, and a position control means for communicating with the locus control means to generate a motor drive signal for each robot. It is characterized by having a save circuit.

[0015]

The deadlock between a plurality of robots can be eliminated by communicating with the evacuation judging means for managing the working state of the robot and the trajectory control means for checking the interference of the robots.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a multi-robot system according to the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram of a control device for a multi-robot system according to a first embodiment of the present invention. In the figure, 11 is work execution means, 12 is evacuation judgment means, and 13
Is a locus control means, and 14 is a position control means. The processing contents of each means will be specifically described below.

The work executing means 11 stores a plurality of work programs in which a detailed sequence of the work of each robot is described by a dedicated command, and sequentially executes the work programs designated by a command from another means. It is possible to execute the work programs assigned to each robot in parallel, whereby the work of multiple robots proceeds at the same time. At the start and end of the execution of one work program, a message to that effect is sent to the evacuation judgment means 12 to inform the execution status of the work. When the command described in the work program is a robot motion command, a robot motion command message is transmitted to the trajectory control means 13 to cause the robot to perform a predetermined motion.

The locus control means 13 performs locus calculation and interference check of the robot at the time when the robot movement command message is received from the work execution means 11, and outputs an operation pulse to the position control means 14 only when no interference occurs. Send. When the interference occurs, the evacuation request message is transmitted to the evacuation determination means 12 to evacuate the robot causing the interference, and the evacuation permission message from the evacuation determination means 12 is waited. When the evacuation permission message is received, the robot causing the interference is retracted to the safe position. However, if the operation command message for the robot causing the interference is received from the work executing means 11 before the evacuation permission message is received. Then, the evacuation request cancellation message is transmitted to the evacuation determination means 12 to operate the robot causing the interference.

When the evacuation judgment means 12 receives the evacuation request message from the trajectory control means 13, the evacuation decision means 12 determines whether or not the robot can be evacuated based on the work state of whether the robot is working or not, and if the evacuation is possible, the trajectory control is performed. An evacuation permission message is transmitted to the means 13. When it is determined that the evacuation is impossible, the fact that the evacuation request is received is stored as the evacuation request existence, and when the evacuation is possible due to the change in the working state of the robot, the evacuation permission message is sent to the trajectory control means 13. Send. When the save request cancel message is received from the trajectory control means 13, the presence or absence of the save request is cleared.

The position control means 14 receives the operation pulse of each robot from the trajectory control means 13, generates a motor drive signal, and outputs it to the motor of each axis to operate the robot.

As described above, the deadlock between the plurality of robots can be eliminated by the communication between the evacuation determination means 12 for managing the working state of the robot and the trajectory control means 13 for checking the interference of the robots.

In the first embodiment described above, the work programs for a plurality of robots are executed by one work executing means 11. However, the same number of work executing means as the number of robots are provided, and the work of one robot is performed. You may make it take charge of a program and each may communicate with an evacuation determination means and a locus control means. The same applies to the position control means 14, and it is also possible to provide the same number of position control means as the robots and to handle one robot each.

Next, a second embodiment of the present invention will be described with reference to FIG. The present embodiment assumes a situation in which two robots A and B execute work in which the order relation is defined. The work content is that the robot grips a part from a part supply device arranged around the robot. However, the work is assembled on a jig provided in the overlapping portion of the operation area. FIG. 2 is an explanatory diagram of a control device for a multi-robot system according to a second embodiment of the present invention.

In FIG. 2, reference numeral 21 is a work order setting means,
Reference numeral 22 is work order storage means, 23 is work execution means A, 24
Is work execution means B, 25 is evacuation judgment means, 26 is trajectory control means, 27 is position control means A, and 28 is position control means B.
Is. The work execution means and the position control means are provided in the same number as two robots, and the symbols A and B represent the robots in charge. Hereinafter, the processing content of each unit in FIG. 2 will be specifically described.

The work order setting means 21 includes robots A and B.
Is a means for setting work order data indicating the order relation of the work programs executed by.

The work order storage means 22 is a data memory for storing the work order data set by the work order setting means 21.

The work executing means 23 and 24 have all the functions described in the first embodiment. As another function, when the command described in the work program is the work continuation confirmation command, the work continuation confirmation message is transmitted to the evacuation determination means 25, and the work continuation permission message is received from the evacuation determination means 25 before the program. Continue to. It is assumed that the work continuation confirmation command is described immediately before the robot grips the component from the supply device or assembles it on the jig.

The function of the trajectory control means 26 will be described by taking as an example the case where a robot operation command message is received from the work execution means A23. When the robot operation command message is received from the work execution means A23, the trajectory of the robot A is calculated and the interference check is performed, and the operation pulse is transmitted to the position control means A27 only when the interference does not occur. When the interference occurs, the evacuation request message is transmitted to the evacuation determination means 25 to evacuate the robot B, and the evacuation determination means 25 holds the evacuation permission message with return. When the evacuation permission message with return is received, the robot B is retracted to the safe position. At this time, the position where the robot B stopped before the retreat is stored as a return position, and after the operation of the robot A is completed, the robot B is moved to the return position. If an operation command message for the robot B is received from the work executing means B24 before receiving the evacuation permission message with return, the evacuation request cancel message is sent to the evacuation judging means 25 as in the case of the first embodiment. And the robot B is operated.

The evacuation judging means 25 is a work executing means 23,
Upon receiving the start and end reports of the program execution from 24, the work progress status is managed. Then, for example, the work executing means B2
When the work continuation confirmation command is received from 4, the robot determines whether or not the work of the robot B should be continued based on the work order data stored in the work order storage means 22 and the work progress status. If it is determined that the work can be continued, a work continue permission message is transmitted to the work executing means B24 to continue the work. However, if it is determined that the work cannot be continued, the message is not transmitted and the work is kept waiting. When the evacuation request message is received from the trajectory control means 26, it is determined whether or not the evacuation is possible based on whether or not the target robot is waiting for work to continue. That is, if the work is waiting to be continued, an evacuation permission message with return is sent to the trajectory control means 26 to evacuate the robot. If not, the fact that the evacuation request is received is saved as the presence or absence of the evacuation request. At the time of waiting, an evacuation permission message with return is transmitted to the trajectory control means 26. When the return report message of the robot which has been retracted from the trajectory control means 26 is received, whether or not the work can be continued is examined again, and if the work can be continued, the work execution permission message is transmitted to the work executing means B24.
When the evacuation request cancellation message is received from the trajectory control means 26, the evacuation request presence / absence is cleared as in the first embodiment.

Position control means A27, position control means B28
Receives the operation pulse of each robot from the trajectory control means 26, generates a motor drive signal, and outputs it to the motor of each axis.

As described above, the evacuation judging means for managing whether the robot is in the waiting state for continuing the work and the locus control means for checking the collision of the robot communicate with each other to evacuate the robot causing the interference and restore the original robot. By returning to the position, the deadlock between the plurality of robots can be eliminated, and the work can be performed in a predetermined order.

In the second embodiment, the case where the work is performed by the two robots has been described. However, in the case of three or more robots, there is no problem if the work order data is set correctly, and the work is performed. This can be realized by providing the same number of execution means and position control means as the robot.

Next, a third embodiment of the present invention will be described. This embodiment is a case where both the evacuation determination means 25 and the trajectory control means 26 described in the second embodiment also have the functions described in the first embodiment, which is different from the second embodiment. The points can be summarized as follows.

In response to the evacuation request message from the trajectory control means 26, the evacuation judgment means 25 judges whether or not evacuation is possible based on two pieces of information, that is, the work status and work progress status of each robot. If the permission message is awaiting the continuation of the work, an evacuation permission message with return is transmitted to the trajectory control means 26.

When the robots interfere with each other, the locus control means 26 sends the evacuation determination means 25 an evacuation permission message for the robot causing the interference, and when the evacuation permission message is received, only the evacuation operation is performed and the robot returns. When the attached save permission message is received, the save and restore operations are performed.

Since the retreat judging means 25 and the trajectory control means 26 have the above-mentioned functions, the retreat judging means 25 and the locus control means 26 are retreated when the non-working robot or the robot waiting for the work order causes the interference, and when the work is waiting, the original work is performed. It becomes possible to return to the position of and continue the work.

Further, in order to avoid deadlock between robots in the second and third embodiments, the operator only has to set the order relation of the work performed by each robot as work order data, and the work relation before and after is set. In consideration of the above, the burden of programming interlock and save operation is released.

[0039]

As described above, according to the present invention, the burden on the operator for avoiding deadlock of a plurality of robots can be reduced, and the deadlock between robots can be completely eliminated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a control device in a multi-robot system according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a control device in a multiple robot system according to a second embodiment of the present invention.

[Explanation of symbols]

 11 Work Execution Means 12 Evacuation Judgment Means 13 Trajectory Control Means 14 Position Control Means 21 Work Order Setting Means 22 Work Order Storage Means 23 Work Execution Means A 24 Work Execution Means B 25 Evacuation Judgment Means 26 Locus Control Means 27 Position Control Means A 28 Position control means B

Claims (3)

[Claims] 1. A system comprising a plurality of robots and a control device for controlling the robots, wherein the control device stores the work programs of the robots and sequentially executes the work programs. Work execution means,
A work state indicating whether each robot is working or not is stored, the work state is updated by communicating with the work executing means, and the non-working robot is saved to a safe position based on the work state. The robot is configured to communicate with the evacuation determining means for determining whether or not to perform the operation, the locus calculation and the interference check of each robot by communicating with the work executing means, and when the interference occurs, the robot communicates with the evacuation determining means. Multiple robot system having a robot retraction circuit composed of trajectory control means for retracting the robot to a safe position, and position control means for communicating with the trajectory control means to generate a motor drive signal for each robot. . 2. A system comprising a plurality of robots and one control device for controlling them, wherein the control device sets work sequence data indicating a sequence relation of work to be executed by each robot. Order setting means, work order storing means for storing the work order data set by the work order setting means, work programs for the robots, and work executing means for sequentially executing the programs The work progress status of each robot is stored, the work progress status is updated by communicating with the work executing means, and the robot waiting for the work order is placed in a safe position based on the work order data and the work progress status. If it is decided to evacuate, wait for the robot to return to its original position and then check the work progress status. Based on the evacuation judging means for judging whether or not the work can be continued based on the communication with the work executing means, the trajectory calculation of the robots and the interference check are performed, and when the interference occurs, the evacuation judging means is communicated. With the robot, the current position of the robot is saved as a return position, the robot is evacuated to a safe position, and the trajectory control means for returning the evacuated robot to the return position is communicated with the trajectory control means. 2. A multi-robot system having a robot withdrawal circuit with return operation, the robot withdrawal circuit comprising position control means for generating the motor drive signal. 3. A system comprising a plurality of robots and one control device for controlling them, wherein the control device sets work sequence data indicating a sequence relation of work to be executed by each robot. Order setting means, work order storing means for storing the work order data set by the work order setting means, work programs for the robots, and work executing means for sequentially executing the programs And storing the work status and work progress status of each robot, updating the work status and the work progress status by communicating with the work executing means, the work status, the work sequence data, and the work progress status. Robots that are not in work or are waiting for work order are judged based on If it is determined that the robot is to be returned to its original position, the evacuation judgment means for judging whether or not the work can be continued based on the work progress state, and the trajectory of each robot by communicating with the work execution means A robot waiting for the work order is stored by saving the current position of the robot as a return position by communicating with the retreat judging means when the calculation and the interference check are performed and communicating with the retreat judging means. Robot retraction circuit with return operation, which includes trajectory control means for returning the robot to the return position when the robot is retracted, and position control means for communicating with the trajectory control means to generate a motor drive signal for each robot. A multi-robot system comprising: