JPH07299792A - Double-armed robot system and its controlling method - Google Patents

Abstract

PURPOSE:To allow a plurality of robots, which might interfere with one another, to perform cooperative works by determining whether or not the interference check for each robot should be made in accordance with on/off of an interference check changeover signal, and thereby preventing the robots from interfering with one another. CONSTITUTION:Receiving an motion command 46 from a working procedure control means 41 of one robot 1, its motion control means 43 gives a motion admit signal 54 to an interference checking means 45. This means 45 sends a motion admit signal 56 to the motion control means 43 of the robot 1 when judgement is such that two robots 1, 2 do not interfere with each other. Further the motion control means 43 of this robot 1 waits for the start of a motion until it receives the motion admit signal 56. Another robot 2 operates in a similar way. Thereto a plurality of interference check changeover signals 58, 59 are added, and when the interference check changeover signals are put off by the working procedure control means 41, 42. the interference check is disengaged temporarily. That is, the robots 1, 2 are left operating whether they might interfere with each other or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-arm robot system and its control method. More specifically, the present invention is a multi-arm system in which a plurality of robots operate in the same area, for example, one robot holds a work and the other robot processes or assembles other parts to the work. The present invention relates to a multi-arm robot system for collaborative work and its control method.

[0002]

2. Description of the Related Art In recent years, as automation of production processes has become more sophisticated, in systems using industrial robots, centralization and integration of robot work have progressed, and in a narrower installation space. Robot control for efficient work is becoming an important issue. And actually,
For example, there is an increasing number of cases where a system is configured with a layout in which a plurality of robots have mutually operable areas.

When a plurality of robots perform work operations in such a small area, even in the conventional systems, interference check is performed for each operation of the robots so that the robots do not collide with each other. It is known that the two do not work at the same time. For example, FIG. 8 illustrates an operation area of a plurality of robots in the conventional example, and FIG. 9 illustrates a configuration of a control device for checking interference of the plurality of robots in the conventional example.

As shown in FIG. 8, a region a1 and a region a2
In the system in which the robot (1) operable in the area a4 and the robot (2) operable in the areas a2, a3, and a4 are arranged, both the robots (1) (2) ), The function of preventing the collision between the robots (1) and (2) is absolutely necessary. In the conventional typical method for preventing the collision, when the robot (1) enters the area a2, it is confirmed that the robot (2) does not exist in the area a2 and that the robot (2) does not try to enter the area a2. When the robot (2) enters the area a2 and confirms that the robot (1) does not exist in the area a2 and does not try to enter the area a2, the operation of entering the area a2 is performed. I am trying to do it. By doing this, it is guaranteed that the robot (1) and the robot (2) do not enter the area a2 at the same time, and the robots (1) and (2) in the area a2 are guaranteed.
The collision between the robots (1) and (2) is prevented in the area a4 by preventing the collisions and performing the same processing in the area a4.

FIG. 9 shows a robot operating procedure therefor. That is, in response to the operation command (46) from the work procedure control means (41) of the robot (1), the robot operation control means (43) sends an operation permission request signal (54) to the interference check means (45). . The interference checking means (45) determines the robot (1) (2) based on which region the current position and the motion target position of the robot (1) and the current position and the motion target position of the robot (2) are.
When it is determined that they do not interfere with each other, an operation permission signal (56) is sent to the operation control means (43) of the robot (1). The motion control means (43) of the robot (1) waits for the motion start until it receives the motion permission signal (56). Also for the robot (2), the robot operation control means (44) sends an operation permission request signal (55) to the interference check means (45) in response to the operation command (47) from the work procedure control means (42). And this interference check means (45)
The motion control means (44) of the robot (2) waits for the start of motion until it receives the motion permission signal (57) from.

Further, the robot (1) and the robot (2) send current position signals (52) and (53) to the operation control means (43) and (44), and drive outputs (50) and (51).
Will be driven by. By performing similar processing and operation, the robots (1) and (2) can operate without collision. On the other hand, as described above, in a plurality of robot systems configured not to monitor for collision prevention, be careful not to collide with each other,
By deciding and programming the order of all robot movements, the robots perform predetermined work without interference.

[0007]

However, in the conventional system configuration as described above, the robots cannot enter the same area at the same time, so that a plurality of robots share a single work piece in the same area. There was a problem that I could not work in. For example, in the case of a multi-arm robot system in which the robot (1) takes out from the component supply unit, sets it at a predetermined position and holds the component, the robot (2) needs a joint work such as screw tightening, A necessary work operation itself, such as a case where another robot processes a part held by the robot, is an operation that is not permitted because it is determined in the interference check that the robots interfere with each other. Therefore, the collision prevention means cannot be used as it is.

It is desirable that the operation of taking out the parts from the parts supply section of the robot (1) and the operation of taking out the screws from the screw supply section of the robot (2) are independently and asynchronously performed. However, if the operations are performed in the wrong order, they collide. Therefore, it is not possible to create a program that performs each operation independently. Therefore, in the case of the conventional system, there is a problem that the program becomes complicated and it takes time to create the program and teach the robot operation, such as when a conditional branch occurs in the operation of taking out from each supply unit in each robot.

Further, since the robots cannot operate asynchronously, there is a drawback that the work time becomes long due to the unnecessary waiting. The present invention has been made in order to solve the conventional problems as described above, there is no concern that a plurality of robots interfere with each other, there is no need for the trouble of program creation and operation teaching, and when performing work. It is an object of the present invention to provide a new multi-arm robot system which can reduce the waiting time of the robot and its control method.

[0010]

A multi-arm robot system according to a first aspect of the present invention for solving the above-mentioned problems is composed of a plurality of robots which independently perform a work operation and a control device therefor, and a control device. Is a work procedure control means for generating operation target position data or an interference check switching signal according to data designating the operation procedure of each robot, robot operation control means for controlling the operation of each robot according to the operation target position data, and this robot. Before the operation control means starts the individual movements of the robots, it checks the interference between the robots, and if it is determined that there is interference, the operation control means has an interference check means for holding the start of the robot operation until it changes to the non-interference state. , This interference check means checks the interference when the interference check switching signal is ON and checks the interference. Toggles signal is characterized by operating the robot regardless of whether or not to interfere when the OFF.

Further, in the multi-arm robot system of the second invention of the present invention, an interference check switching signal exists for each robot in the multi-arm robot system of the first invention, and the interference checking means outputs the interference check switching signal. Check the interference of multiple robots that are not both OFF.

Furthermore, a control method according to a third invention of the present invention for solving the problem is a system comprising a plurality of robots independently performing a work operation and a control device thereof, wherein the control devices are robots that interfere with each other. The interference check means that does not permit the action to be performed, and transmits the first signal to the second robot as a control procedure of the first robot,
After temporarily canceling the interference check, there is a step of waiting until the second signal transmitted from the second robot is received and restarting the interference check at the time of reception. 1st sent from one robot
It is characterized in that it includes a process of waiting until the signal is received, temporarily canceling the interference check at the time of reception, and a process of restarting the interference check and simultaneously transmitting the second signal to the first robot.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a control device and control method for a multi-arm robot system according to the present invention. As is apparent from FIG. 1, in the present invention, interference check switching signals (58) and (59) are added to the configuration of FIG. 9 described as a conventional example, and the work procedure control means (41) ( When the interference check switching signal is turned off from 42), the interference check can be temporarily canceled. In addition, work procedure control means (4
1) and (42) also have means for transmitting and receiving communication signals (61) and (62) to each other.

Since the multi-arm robot system of the first aspect of the present invention is configured to determine whether or not to perform the interference check by turning ON / OFF the interference check switching signal, robot operations that may interfere with each other are performed. When it is necessary, the interference check switching signal can be turned off, and a plurality of robots can work together on one work.

Further, in the multi-arm robot system of the second invention, the interference check is not performed only when both of the plurality of robots are in the interference check switching signal OFF. Even if is executed without being synchronized for each robot, there is no risk of accidentally colliding robots because the operation timing has changed.

Further, in the method for controlling a plurality of robots according to the third aspect of the invention, as shown in the flow chart of FIG. 2, since the communication for switching the interference check and waiting for the work procedure are simultaneously performed, the first robot is used. It is possible to easily and accurately create a program for performing multi-arm joint work such as screw tightening in a region where the second robot interferes while holding the work.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 3, horizontal articulated robots (1) and (2) are installed on a pedestal (3), and a hand (4) for holding parts is attached to the tip of the robot (1). A screw tightening driver (5) for adsorbing a screw and tightening the screw is attached to the tip of the. The work to which the parts are screwed is carried from the left by the conveyor (6) together with the jig pallet,
After stopping at the assembling station (7), parts are set by the robot (1), screwed by the robot (2), and then conveyed to the right by a conveyor.

The robot (1) sequentially takes out the parts arranged on the tray supplied by the tray feeder (8) from the end, sets the parts on the work on the jig pallet of the conveyor, and holds them. The robot (2) takes out the screw from the screw feeder (9) and tightens the screw on the part held by the robot (1). The layout of this system is shown in FIG. The operation areas of the robots (1) and (2) are (10) and (11), respectively, and there is a possibility that they will interfere with each other in the area (12) on the conveyor and the area (13) for supplying parts.

For example, the robot (1) carries out a retry operation for taking out the next component when the picking up of the component fails, and the robot (2) takes out the screw when picking up the screw from the screw feeder fails. Perform retry operation. In addition, when parts run out in a tray that supplies parts or a screw feeder that supplies screws, the tray hood can be operated continuously even when parts are replenished using a spare tray feeder or spare screw feeder. If two robots (14) and (15) are installed and three screw feeders (16), (17) and (18) are installed, and the robot is at a different operation position when replenishing components There is. As described above, in this system, each robot has its own work procedure, the work is executed asynchronously, and the execution timing and the operation position are not constant.

Therefore, this system is controlled by the control device described below. FIG. 5 is an explanatory diagram of hardware of the control device. The control device includes a central control unit (1) having a CPU (21), a memory (22) and an input / output device (23).
9), a robot operation control section (20) having a CPU (25), a memory (26) and an input / output device (27), and a 2-port RAM (2) of the robot operation control section (20).
The CPU (21) of the central control unit and the CPU (25) of the robot operation control unit read and write 4) so that the central control unit (19) and the robot operation control unit (20) communicate with each other. The input / output device (27) of the robot operation control unit includes an output command signal line of a motor for driving a robot joint, an encoder signal line for detecting the current position of the robot joint, and a motor drive control device (28) ( The robots (1) and (2) are connected via 29). The input / output device (23) of the central control unit includes the input / output device (30) of the operating device, the valve (31) for opening and closing the hand, the control device (32) for the conveyor, and the control device for the tray feeder / screw feeder. Sensors and actuators other than the robot, such as (33), are connected.

The work procedure control means (4) of the present invention
1) and 42) are realized by a program stored in the memory of the central control unit, and the robot operation control means (43) and (44) and the interference check means (4) of the present invention are implemented.
5) is realized by a program stored in the memory of the robot operation control unit (20). Central control unit (1
In the memory (22) of 9), data designating an operation procedure for each robot is stored, and the CPU of the central control unit sequentially reads this data and performs a process corresponding to the data, thereby performing the robot work. Is realized. The data includes data for designating the operation of the robot, data for instructing ON / OFF of the interference check switching signal, data for instructing opening / closing of the hand, and the like.

The CPU (21) of the central controller (19) is
For example, when the data designating the robot motion is read, the motion target position data is read, the motion command is communicated to the robot motion control unit, and the robot number and the motion target position are sent. Interference check switching signal OFF
When the data for instructing is read, communication of the interference check switching signal OFF is performed to the robot operation control unit. When the data for instructing to open the hand is read, the input / output processing for opening the hand is performed.

The memory (22) of the central control unit (19) stores the above-mentioned data string for each robot, and the CPUs of the central control unit are processed asynchronously in parallel by multitask processing. When the robot operation command of the robot (1) is issued, the reading of the data string related to the robot (1) and the execution of the processing are made to wait until the operation of the robot (1) is completed, but during that time, the robots other than the robot (1) The reading of the data string regarding and the execution of processing are performed.

The robot operation control section (20) receives a robot operation command or an interference check switching signal ON / OFF command from the central control section (19) and performs a process corresponding thereto. When the interference check switching signal ON / OFF command is received from the central control unit (19), the robot operation control unit (20) performs the processing of the flow shown in FIG.
The interference check switching flag of the designated robot in the memory (26) of the robot operation control section (20) is set or reset.

When the robot operation command is received from the central control section (19), the robot operation control section (20) carries out the processing of the flow shown in FIG. That is, when the operation command of the robot (1) is received, the value of the interference check switching flag of each robot stored in the memory is confirmed, and when the interference check switching flag of the robot (1) is ON, the interference check switching flag is ON. Move on to processing. When the interference check switching flag of the robot (1) is OFF, the robot (1)
Interference check processing is performed for robots other than those for which the interference check switching flag is ON. The interference check switching flag of the robot (1) is OFF, and the interference check switching flags of the robots other than the robot (1) are OFF, the robot operation processing is performed without performing the interference check. In this embodiment, since there are two robots, the interference check is not performed only when both robots are OFF.

The interference check processing is performed as follows. The second arm swing center at the motion start position and the target motion position of the robot (1) is defined as Pis, Pie, and the second arm swing center Pjs, Pje at the current motion position and the motion target position of another robot to be checked is defined. . When the other robot is not operating, Pjs and Pje are at the same position. The length of the second arm of the two robots is Li2, Lj2, and the radius of the hand and tool is H
i, Hj, and the predetermined distance L is Li2, Lj2, Hi, H
Let it be the sum of j.

L = Li2 + Lj2 + Hi + Hj The distance between Pis and Pjs is D1, the distance between Pis and Pje is D2, the distance between Pie and Pjs is D3, and the distance between Pie and Pje is D4. D1, D2, D3, D4
If it is greater than the minimum value of the predetermined distance L, it is determined that there is a possibility of interference and waits for the start of the operation. If it is less than L, it is determined that there is no possibility of interference and the operation processing is performed. .

In the process of motion, interpolation calculation is performed between the motion start position and the motion target position, the rotation target position of the motor for driving the robot joint is repeatedly calculated for each unit time, and the motor is rotationally controlled to the motion target position. Output. When the rotation of the motor that drives each joint reaches the operation target position, the completion of the operation is reported to the central control unit. When the central control unit receives a report of the end of the operation from the robot operation control unit, it reads the next data of the robot operation command and then performs the corresponding processing.

In the present embodiment, there are two robots, and the data designating the processing of the flow shown in FIG. 2 is stored in the memory of the central control unit. In the data string that specifies the work procedure of the robot (1), the robot moves to move the hand onto the tray to which the parts are supplied. The output process of the hand that holds the parts on the tray is performed.

It is confirmed that the work has been loaded on the conveyor, and if it has not been loaded, the process waits until it is loaded. Performs robot operation to move parts onto the work. Data is transmitted to the robot (2) and an instruction to turn off the interference check switching signal is issued.

After waiting for the data reception from the robot (2), the interference check switching signal ON command is issued. Output processing of grip release of the hand holding the component is performed. The robot moves away from the work. Carry out the work on the conveyor and carry out the output process to carry in the next work. The procedure is specified to be performed.

In the data string designating the work procedure of the robot (2), the robot is controlled to move the tool onto the screw feeder. Performs output processing of the tool that sucks screws. After waiting for data reception from the robot (1), the interference check switching signal OFF command is issued after reception.

A robot operation for moving the screw tightening tool onto the work / part is performed. Performs tool output processing to tighten the screws on the work / part. After tightening the screws, the robot moves away from the work / part. Data is transmitted to the robot (1) and an instruction to turn on the interference check switching signal is issued. The procedure is specified to be performed.

By the CPU of the central control unit sequentially reading out these data and performing the corresponding processing, the two robots take out parts asynchronously and perform screw taking-out operations correctly while avoiding collision with each other. It is possible to perform work to fix parts to work with screws.
As described above, according to this embodiment, in a system in which a plurality of robots wait when performing joint holding work, and during the other operations, the robots perform work operations asynchronously with each other, the program of each robot is There is no risk of collision even if you create independently without worrying about the work procedure of other robots. In addition, interference can be turned off during holding work.
In this case, since only one robot operates, it suffices to pay attention only to the teaching regarding the operation position of the robot for which the interference check during holding work is OFF.
Don't worry about making a mistake.

[0035]

As described above, according to the first invention of the present invention,
By deciding whether or not to perform the interference check by turning on / off the interference check switching signal, a plurality of robots that may interfere with each other may be interfered with each other in a system of a plurality of robots that prohibits the operation of interfering with each other. It is possible to realize an excellent multi-arm robot system that enables the collaborative work of other robots.

Further, in the second invention of the present invention, by adopting a configuration in which the interference check is not performed only when both of the plurality of robots are in the interference check switching signal OFF, the operation procedure of the work of the plurality of robots is made. Even if the robots are executed without being synchronized with each other, it is possible to realize an excellent multi-arm robot system in which there is no risk of accidentally colliding robots due to a change in operation timing.

According to the third aspect of the present invention, the process of simultaneously performing switching for interference check and communication for waiting for work procedure is included in the control procedure of each robot, so that the first robot holds the work. Second while
It is possible to realize an excellent control method for a plurality of robots, which can easily and accurately create a program for performing multi-arm joint work such as screw tightening in an area where the robots interfere with each other.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of a control device of the present invention.

FIG. 2 is a flowchart of an operation procedure of a plurality of robots according to the present invention.

FIG. 3 is a configuration diagram of a robot system according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a system layout according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of hardware of a control device according to an embodiment of the present invention.

FIG. 6 is a flowchart of a process of turning on / off the interference check switching signal according to the embodiment of the present invention.

FIG. 7 is a flowchart of a process of robot operation according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram of motion areas of a plurality of robots in a conventional example.

FIG. 9 is a configuration diagram of a control device for checking interference of a plurality of robots in a conventional example.

[Explanation of symbols]

 1, 2 robot 41 work procedure control means for robot 1 42 work procedure control means for robot 2 43 robot operation control means for robot 1 44 robot operation control means for robot 2 45 interference check means 46 robot 1 operation command 47 robot 2 Operation command 48 Robot 1 operation end report signal 49 Robot 2 operation end report signal 50 Robot 1 drive output 51 Robot 2 drive output 52 Robot 1 current position signal 53 Robot 2 current position signal 54 Robot 1 operation permission Request signal 55 Motion permission request signal of robot 2 56 Motion permission signal of robot 1 57 Motion permission signal of robot 2 58 Interference check switching signal of robot 1 59 Interference check switching signal of robot 2 61, 62 Communication signal of robots 1 and 2

Claims (3)

[Claims] 1. A plurality of robots that independently perform a work operation and a control device therefor, wherein the control device outputs operation target position data or an interference check switching signal according to data designating an operation procedure of the robot for each robot. The generated work procedure control means and the robot operation control means for controlling the operation of each robot according to the operation target position data, and the robot operation control means check the interference between the robots before starting the individual operation of the robots, and If so, the robot has an interference check means for holding the start of the robot operation until it changes to the non-interfering state. The interference check means checks the interference when the interference check switching signal is ON, and the interference check is performed. When the switching signal is OFF, the robot is Fukuude robot system, characterized in that to create. 2. The interference check switching signal exists for each robot, and the interference checking means checks the interference between two robots whose interference check switching signals are not both OFF. Multi-arm robot system. 3. A multi-arm robot system comprising a plurality of robots that independently perform a work operation and a control device for the robot, wherein the control device has an interference check means that does not allow the robots to interfere with each other. As the control procedure of the first robot, after transmitting the first signal to the second robot and temporarily canceling the interference check, waiting until the second signal transmitted from the second robot is received, As a control procedure of the second robot, including a process of restarting the interference check at the time of reception, a process of waiting until the first signal transmitted from the first robot is received and temporarily canceling the interference check at the time of reception. A method for controlling a multi-arm robot system, comprising the step of restarting the interference check and transmitting a second signal to the first robot at the same time.