JP7575691B2 - Robot control device and robot system - Google Patents

Description

The present invention relates to a device that executes a control program to control a robot.

As production equipment using robots becomes more sophisticated, there is a need to operate robots based on operation commands from a higher-level control device that exists separately from the controller attached to the robot. An example of a higher-level control device is a PLC (Programmable Logic Controller) that controls multiple industrial devices including robots in parallel. Conventionally, in a control system including a PLC and a robot, the PLC would output a trigger signal to the robot's controller to start the execution of a control program, or send a very simple command to have the controller temporarily execute it.

In response to this, for example, the PLC can also be equipped with the control programs for each robot, and the PLC can directly control each robot instead of the controller, making it easy to link multiple robots together and control them cooperatively.

Special Publication No. 2013-526418

In a control system like the one above, the controller's operating mode needs to be switched between a mode in which the controller executes its own control program and a mode in which the controller executes a control program stored in the PLC. In this case, it is desirable for the user to be able to flexibly switch between operating modes, but safety must also be taken into consideration.

The present invention was made in consideration of the above-mentioned circumstances, and its purpose is to provide a robot control device and robot system that can easily switch between self-control and control by an external control device while ensuring safety.

According to the robot control device of claim 1, the communication unit controls multiple industrial devices in parallel and communicates with an external control device having an external storage unit in which an external control program for the robot is stored. The information storage unit stores mode information that is set by the user and is used to set the operation mode of the control unit to either the internal mode or the external mode. The control unit is configured to be able to perform control based on the execution of the external control program by communicating with the external control device.

If the mode information indicates the internal mode, the control unit enables control based on the internal control program and disables control based on the external control program; if the mode information indicates the external mode, the control unit enables control based on the external control program and disables control based on the internal control program.

With this configuration, the operating mode of the control unit can be set to either internal mode or external mode based on the mode information set by the user and stored in the information storage unit. In the internal mode, control by the control unit based on the external control program is disabled, and in the external mode, control based on the internal control program is disabled, so that only one of the control programs can always be used for control.

As a result, in internal mode the control device can control the robot by executing an internal control program as before, and in external mode the control device can control the robot by carrying out control based on an external control program. This makes it possible to diversify the control form of the robot according to the needs of the user.

The information storage unit is a non-volatile memory, and the mode information is transferred from the non-volatile memory to a volatile memory that the control unit uses as a work area. The control unit then reads the mode information transferred to the volatile memory and determines the operation mode. With this configuration, the mode information set by the user is stored in the non-volatile memory, so the information content is retained even if the power supply is cut off. Therefore, it is no longer necessary to set the mode information every time control of the robot is started.

According to the robot control device of claim 2 , the transfer of mode information from the non-volatile memory to the volatile memory is performed during the initialization process after power is turned on. This makes it possible to switch the operation mode even after control of the robot has once been started in one operation mode by resetting the mode information and then turning the power of the control device back on.

According to a third aspect of the present invention, the robot system includes the robot control device according to the first or second aspect of the present invention, and an external control device that controls a plurality of industrial devices in parallel and has an external storage unit in which an external control program for controlling the robot is stored. With this configuration, the execution of the internal control program installed in the control device and the execution of the external control program installed in the external control device can be switched according to mode information set in the control device by the user, thereby diversifying the control form of the robot.

FIG. 1 is a functional block diagram showing a configuration of a robot system according to an embodiment. A functional block diagram showing the configuration of a control system for production equipment in a factory controlled by an external control device. Flowchart showing operation mode setting process Flowchart showing operation mode determination processing FIG. 1 is a diagram showing a form of communication performed between an external control device and a controller.

One embodiment will be described below with reference to the drawings. The robot system 1 shown in FIG. 1 is, for example, a general industrial robot system, and includes a robot 2, a controller 3 that controls the operation of the robot 2, a teaching device 4 for operating and displaying the robot 2, and an external control device 5 such as a PLC. The robot 2 is, for example, a six-axis vertical articulated robot. The controller 3 communicates with the teaching device 4 and the external control device 5 via communication boards 6 and 7.

Figure 2 shows a control system for production equipment in a factory, for example, that includes part of the configuration shown in Figure 1 and also shows other equipment controlled by an external control device 5. The external control device 5 controls two robots 2A, 2B via controllers 3A, 3B, and also communicates with a camera 21 and a machine tool 22 to control these devices as well. In this way, the external control device 5 controls multiple devices collectively, making it possible to improve the accuracy of synchronized operation between the robots 2A, 2B and the machine tool 22.

In FIG. 1, the functional blocks from the communication board 6 to the motor controller 11 are functions that are provided in a conventional controller 3. The teaching device 4 is used by the user to input information to operate the controller 3, and is called, for example, a teaching pendant. The user uses the teaching device 4 to teach the robot 2 how to move, and inputs instructions to start the taught movement. The instructions input to the teaching device 4 are input to the controller 3 via the communication board 6, and are interpreted as information that can be processed by the controller 3.

The path generator 8 has an internal storage unit in which an internal control program 12 is stored, and generates a motion path for the robot 2 based on the internal control program 12. The motion generator 9 generates command angles for the six motors 13 corresponding to the six axes of the robot 2, for example every 8 ms, based on the generated motion path. The calculator 10 divides the generated command angles into control periods of the motors 13, for example 1 ms. Then, it generates a PWM signal or the like according to the divided command angles and outputs it to the motor controller 11. The motor controller 11 is, for example, a drive circuit such as an inverter, and there are six motor controllers 11 corresponding to the six motors 13. The calculator 10 and the motor controller 11 correspond to the control unit.

The external control device 5 has an external storage unit in which an external control program 14, which is a control program for the robot 2, is stored. The external control program 14 is a program corresponding to the control form of the robot 2 shown in FIG. 2. On the other hand, the internal control program 12 is a program corresponding to the case where the controller 3 controls the robot 2 alone. The external control device 5 also has functions corresponding to the path generator 8 and the motion generator 9, and the communication board 7, which corresponds to the communication unit, outputs to the calculator 10 the same type of signal as the signal output from the motion generator 9.

Next, the operation of this embodiment will be described. In the operation mode setting process shown in FIG. 3, the user first inputs an operation mode setting request to the controller 3 via the teaching device 4 (S1). The controller 3 checks the setting value of the operation mode input by the user to the teaching device 4 (S2). The setting value is then written and stored in the storage area 15, which is the information storage section of the controller 3 (S3). The storage area 15 is divided into an area 16 of non-volatile memory such as flash ROM and an area 17 of non-volatile memory such as RAM, and the setting value of the operation mode is stored in area 16. This completes the setting process (S4). The setting value corresponds to mode information.

In the operation mode determination process shown in Fig. 4, when the power supply to the controller 3 is turned on (S11), an initialization process is executed (S12). In this initialization process, as shown in the figure, the mode setting value stored in area 16 is transferred to area 17. Next, the calculator 10 checks the operation mode, referring to the mode setting value transferred to area 17 (S13). Then, a start-up process corresponding to each operation mode is executed (S14), and the start-up of the controller 3 is completed (S15).
Here, the mode setting value may be, for example, a one-bit flag, and two operation modes may be assigned as follows:
<Mode setting value><Operationmode>
0 Internal mode
1 External mode

In the "internal mode", the calculator 10 obtains a command angle from the motion generator 9 and controls the robot 2 based on the internal control program 12. On the other hand, in the "external mode", the calculator 10 obtains a command angle from the external control device 5 via the communication board 7 and controls the robot 2 based on the external control program 14. In the "external mode", the external control device 5 essentially controls the motor controller 11 via the calculator 10.

Figure 5 shows the form of communication between the external control device 5 and the controller 3, and the communication protocol is, for example, EtherCAT (registered trademark). As shown in Figure 5, communication is divided into periodic communication that is performed at regular intervals, and non-periodic communication that is performed during intervals when no periodic communication is performed. In periodic communication, data required for each control cycle of the external control device 5, such as the command position, current position, and current speed, is sent and received. On the other hand, in non-periodic communication, data required immediately after startup or when settings are changed, such as the origin position of the robot 2 and the settings of the motor 13, is sent and received.

As described above, according to this embodiment, in the controller 3, the communication board 7 communicates with the external control device 5 that controls multiple industrial devices in parallel. Area 16 of the storage area 15 stores a mode setting value that is set by the user and is used to set the operation mode of the calculator 10 to either the internal mode or the external mode. The calculator 10 is also configured to be capable of being controlled based on the external control program 14 transmitted from the external control device 5.

When the mode setting value indicates the internal mode, the control based on the internal control program 12 by the calculator 10 is enabled and the control based on the external control program 14 is disabled; when the mode setting value indicates the external mode, the control based on the external control program 14 is enabled and the control based on the internal control program 12 is disabled.

With this configuration, the operating mode of the calculator 10 can be set to either the internal mode or the external mode based on the mode setting value set by the user. In the internal mode, execution of the external control program 14 by the calculator 10 is disabled, and in the external mode, execution of the internal control program 12 is disabled, so that control based on only one of the control programs is always possible.

As a result, in the internal mode, the controller 3 can control the robot 2 by executing control based on the internal control program 12 as before, and in the external mode, the controller 3 can control the robot 2 based on the external control program 14. This makes it possible to diversify the control form of the robot 2 according to the needs of the user. In addition, in the system configuration shown in FIG. 2, by having the controllers 3A and 3B perform control in the external mode, it becomes possible to achieve highly accurate synchronized operation not only between the robots 2A and 2B, but also with other production equipment such as the machine tool 22. This makes it possible to reduce takt time and apply the system to highly difficult applications. In particular, when the controllers 3A and 3B are different products, the accuracy of synchronous operation between them is improved.

The mode information is also transferred from area 16, which is a non-volatile memory, to area 17, which is a volatile memory used by the calculator 10 as a working area, and the calculator 10 reads the mode information transferred to area 17 to determine the operation mode. With this configuration, the contents of the mode setting value set by the user are retained even if the power supply is cut off. Therefore, it is not necessary to set the mode setting value every time control of the robot 2 is started. The transfer from area 16 to area 17 is performed during the initialization process after the power is turned on. As a result, even after control of the robot 2 has been started in one operation mode, the operation mode can be switched by resetting the mode setting value and then turning the power of the controller 3 back on.

The present invention is not limited to the embodiments described above or illustrated in the drawings, and the following modifications and extensions are possible.
The cycle for generating the command angle is not limited to 8 ms.
The robot is not limited to a vertical six-axis type, but may be a horizontal four-axis type, etc.
The mode setting value does not necessarily have to be transferred from area 16 to area 17 before being read into the arithmetic unit 10 .
The communication protocol is not limited to EtherCAT.
Industrial equipment other than the camera 21 and the machine tool 22 may also be subject to control by the external control device 5 .

In the drawing, 1 is a robot system, 2 is a robot, 3 is a controller, 4 is a teaching device, 5 is an external control device, 7 is a communication board, 10 is a calculator, 12 is an internal control program, 14 is an internal control program, 15 is a storage area, 16 and 17 are areas, 21 is a camera, and 22 is a machine tool.

Claims (3)

an internal storage unit in which an internal control program for controlling the robot is stored;
A control unit that performs control based on execution of the control program;
a communication unit for communicating with an external control device having an external storage unit in which an external control program for controlling a plurality of industrial devices in parallel and controlling the robot is stored;
an information storage unit that stores mode information set by a user for setting the operation mode of the control unit to either an internal mode or an external mode;
The control unit is configured to be capable of control based on the external control program executed by the external control device,
When the mode information indicates an internal mode, the control based on the internal control program by the control unit is enabled, and the control based on the external control program is disabled;
When the mode information indicates an external mode, the control based on the external control program by the control unit is enabled, and the control based on the internal control program is disabled ;
the information storage unit is a non-volatile memory,
The mode information is transferred from the non-volatile memory to a volatile memory used by the control unit as a working area,
The control unit is a robot control device that reads the mode information transferred to the volatile memory and determines the operation mode . 2. The robot control device according to claim 1 , wherein the mode information is transferred from the non-volatile memory to the volatile memory during initialization processing after power is turned on. A robot control device according to claim 1 or 2 ;
A robot system comprising: an external control device that controls a plurality of industrial devices in parallel and has an external memory unit in which an external control program that controls the robot is stored.

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