Robot system

Abstract

The robot system (100) includes a robot (10), a drive unit (12), a first control unit (21) that controls an operation of the robot (10), and a second control unit (22) that controls power supplied to the drive unit (12) based on a command from the first control unit (21). The first control unit (21) and the second control unit (22) monitor the operating state of each other and detect an abnormality in the operation of the robot (10), and when an operation abnormality, which is an abnormality in at least one of the operating state and the operation of the robot (10), is detected, the first control unit (21) and the second control unit (22) each output a stop command for stopping the operation of the drive unit (12).

Description

Technical Field

[0001] The present disclosure relates to a robot system, and particularly to a robot system including a control unit that controls the operation of the robot. Background Art

[0002] Conventionally, a robot system including a control unit that controls the operation of the robot has been known. For example, Japanese Patent No. 3114579 discloses a control device for an industrial robot. The control device for the industrial robot includes a main CPU unit and a servo CPU unit. The main CPU unit outputs a speed command signal for the robot. The servo CPU unit operates the servo motors of the respective axes of the robot at the speed indicated by the speed command signal from the main CPU unit. Further, in the control device for the industrial robot described in Japanese Patent No. 3114579, comparison units are provided in the main CPU unit and the servo CPU unit, respectively. The comparison unit compares the actual speed calculated based on the signal from an encoder that obtains the rotation amount of the servo motors of the respective axes of the robot with the command speed commanded by the main CPU unit. Then, when the comparison result exceeds an allowable value, an abnormality generation process is executed in the main CPU unit and the servo CPU unit, respectively.

[0003] Patent Document 1: Japanese Patent No. 3114579

[0004] However, in the control device for the industrial robot described in Japanese Patent No. 3114579, since the rotation of the servo motor is controlled by the servo CPU unit based on the command generated by the main CPU unit, when an abnormality occurs in the main CPU unit, the command itself output from the main CPU unit to the servo CPU unit becomes abnormal, and thus the control of the servo motor cannot be performed normally. In this case, even when comparing the command from the main CPU unit with the actual speed of the rotation of the servo motor as in Japanese Patent No. 3114579, it is difficult to correctly detect an abnormality in the operation of the robot. Therefore, it is desired to correctly detect an abnormality in the operation of the robot when controlling the operation of the robot using two different control units. Summary of the Invention

[0005] The present disclosure has been made to solve the above-described problems, and an object of the present disclosure is to provide a robot system that can correctly detect an abnormality in the operation of the robot when controlling the operation of the robot using two different control units.

[0006] A robot system according to one aspect of the present disclosure includes: a robot; a drive unit that serves as a drive source for causing the robot to operate; a first control unit that controls the operation of the robot; and a second control unit that controls the power supplied to the drive unit based on an instruction from the first control unit. The first control unit and the second control unit mutually monitor each other's operation states and detect abnormalities in the operation of the robot. When an abnormality in at least one of the operation state and the operation of the robot, that is, an operation abnormality, is detected, the first control unit and the second control unit respectively output a stop instruction for stopping the operation of the drive unit.

[0007] In the robot system according to one aspect of the present disclosure, as described above, the first control unit and the second control unit mutually monitor each other's operation states and detect abnormalities in the operation of the robot. When an abnormality in at least one of the operation state and the operation of the robot, that is, an operation abnormality, is detected, a stop instruction for stopping the operation of the drive unit is output. Thus, when the operation of the robot is controlled by two different control units, namely the first control unit and the second control unit, the first control unit and the second control unit can mutually detect abnormalities occurring in each of the first control unit and the second control unit by mutually monitoring the operation states. Therefore, the first control unit and the second control unit that have mutually confirmed that no abnormality has occurred can respectively detect abnormalities in the operation of the robot. As a result, when the operation of the robot is controlled by two different control units, abnormalities in the operation of the robot can be correctly detected.

[0008] According to the present disclosure, when the operation of the robot is controlled by two different control units, abnormalities in the operation of the robot can be correctly detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram showing the overall structure of a robot system in one embodiment.

[0010] Figure 2 It is a block diagram showing the overall structure of a robot system in one embodiment.

[0011] Figure 3 It is a diagram for explaining the configuration of the first control unit, the second control unit, and the stop control unit in a robot controller.

[0012] Figure 4 It is a block diagram for explaining the structure of the first control unit, the second control unit, and the stop control unit in a robot controller.

[0013] Figure 5It is a flowchart for explaining the control method of a robot system in the case where an abnormal action is detected. Detailed implementation mode

[0014] Hereinafter, embodiments of the present disclosure in which the present disclosure is embodied will be described based on the drawings.

[0015] (Overall structure of the robot system)

[0016] Refer to Figures 1 to 4 The structure of the robot system 100 in one embodiment will be described.

[0017] As Figure 1 shown, the robot system 100 includes a robot 10 and a robot controller 20. The robot system 100 performs, for example, a workpiece W handling operation. In addition, the robot 10 has a robot arm 11. An end effector 15 for performing the handling operation is attached to the robot arm 11. The end effector 15 is, for example, a robot hand that holds the workpiece W. The robot 10 is connected to the robot controller 20 and operates under the control of the robot controller 20. The robot 10 is, for example, a 6-axis vertical articulated robot.

[0018] As Figure 2 shown, the robot controller 20 has a first control unit 21, a second control unit 22, a stop control unit 23, a drive circuit unit 24, an input / output module 25, and a communication module 26. The first control unit 21, the second control unit 22, the stop control unit 23, the drive circuit unit 24, the input / output module 25, and the communication module 26 are arranged inside a housing 20a of the robot controller 20. The housing 20a has a rectangular parallelepiped shape. In addition, the robot controller 20 is connected to an external stop switch 101 and a PLC 102 (Programmable Logic Controller).

[0019] The drive unit 12 is arranged on the robotic arm 11. The drive unit 12 serves as a drive source for operating the robot 10. That is, the drive unit 12 operates the robotic arm 11. The robotic arm 11 rotates and moves by means of the drive unit 12. The drive unit 12 includes a servo motor 13 and an encoder 14. The servo motor 13 rotates when supplied with power. For example, the servo motor 13 rotates its rotating shaft by means of three-phase alternating current. The encoder 14 detects the rotation angle of the servo motor 13. Moreover, the encoder 14 outputs the detected value representing the rotation angle of the servo motor 13 to the first control unit 21 and the second control unit 22. Specifically, a signal representing the detected value from the encoder 14 is input to the second control unit 22. Moreover, via the second control unit 22, a signal representing the detected value is input to the first control unit 21. In the robotic arm 11 of the robot 10, two linearly extending arm portions are connected to each other via a joint portion. In addition, at the end of the arm portion on the front end side, an end effector 15 is mounted via a separate joint portion. Moreover, the robotic arm 11 is connected to the base portion. A separate joint portion is further arranged on the base portion side of the robotic arm 11. The drive unit 12 is arranged at each joint portion. Specifically, in a six-axis vertical articulated robot, that is, the robot 10, six drive units 12 are arranged. In addition, the encoder 14 is an example of a rotation angle detection unit.

[0020] In the present embodiment, the first control unit 21 controls the operation of the robot 10. Specifically, the first control unit 21 is a main control unit that controls the overall operation of the robot 10. The second control unit 22 controls the power supplied to the drive unit 12 based on an instruction from the first control unit 21. That is, the second control unit 22 is a servo control unit that controls the operation of the servo motor 13. The stop control unit 23 performs control to stop the operation of the drive unit 12. The stop control unit 23 is independent of the first control unit 21 and the second control unit 22 as a third party, and controls the stop of the operation of the robot 10 based on signals from the first control unit 21 and the second control unit 22. The first control unit 21, the second control unit 22, and the stop control unit 23 perform control using programs and parameters stored in a storage unit 31a described later. The control performed by the first control unit 21, the second control unit 22, and the stop control unit 23 will be described in detail later.

[0021] As Figure 3 shown, the first control unit 21, the second control unit 22, and the stop control unit 23 are respectively arranged on independent substrates. Specifically, the first control unit 21 is arranged on the first substrate 31. The second control unit 22 is arranged on the second substrate 32. Moreover, the stop control unit 23 is arranged on the third substrate 33. The first substrate 31 is connected to the second substrate 32 and the third substrate 33 respectively.

[0022] The first control unit 21 includes, for example, a CPU (Central Processing Unit). In addition, the second control unit 22 is the same as the first control unit 21 and includes a CPU. In addition to the first control unit 21 and the second control unit 22, storage devices such as an IC (Integrated Circuit) for power supply and a RAM (Random Access Memory) (not shown) are respectively arranged on the first substrate 31 and the second substrate 32. In addition, a storage unit 31a is arranged on the first substrate 31. The storage unit 31a stores programs and parameters to be executed by the first control unit 21 and the second control unit 22. The storage unit 31a includes, for example, a flash memory such as a CFast. In addition, the stop control unit 23 independently has a first stop control unit 23a and a second stop control unit 23b. The first stop control unit 23a and the second stop control unit 23b respectively include, for example, a CPLD (Complex Programmable Logic Device).

[0023] The first control unit 21 and the second control unit 22 mutually transmit and receive signals. The first control unit 21 and the second control unit 22 transmit and receive signals through serial communication, for example. In addition, the first control unit 21 respectively transmits and receives signals with the first stop control unit 23a and the second stop control unit 23b of the stop control unit 23. Moreover, the second control unit 22 respectively transmits and receives signals with the first stop control unit 23a and the second stop control unit 23b of the stop control unit 23 via the first control unit 21. For example, the first control unit 21 respectively transmits and receives signals with the first stop control unit 23a and the second stop control unit 23b through parallel communication based on a 16-bit bus. In addition, by converting the signals obtained by the first control unit 21 from the second control unit 22 through serial communication into a 16-bit bus, the second control unit 22 respectively transmits and receives signals with the first stop control unit 23a and the second stop control unit 23b via the first control unit 21.

[0024] In addition, the first substrate 31 on which the first control unit 21 is arranged is arranged so as to overlap the second substrate 32 on which the second control unit 22 is arranged in the thickness direction of the substrate. In addition, the third substrate 33 on which the stop control unit 23 is arranged is arranged so as to overlap the second substrate 32 in the thickness direction of the substrate and is arranged adjacent to the first substrate 31.

[0025] As Figure 4As shown, the drive circuit unit 24 supplies power to the drive unit 12. Specifically, the drive circuit unit 24 includes a conversion circuit that supplies alternating current to the servo motor 13 of the drive unit 12. The drive circuit unit 24 has a plurality of switching elements Sw. The plurality of switching elements Sw control the switching operation through the control by the second control unit 22. In addition, in the conversion circuit of the drive circuit unit 24, the switching element Sw on the upper arm side and the switching element Sw on the lower arm side, which are connected in series with each other, are connected in parallel. For the plurality of switching elements Sw, in order to supply three-phase alternating current to the servo motor 13, there are 3 switching elements Sw on the upper arm side and 3 switching elements Sw on the lower arm side for each drive unit 12. That is, in order to supply current to each of the plurality of drive units 12, the drive circuit unit 24 has a plurality of conversion circuits corresponding to the plurality of drive units 12 respectively.

[0026] As Figure 3 shown, the input / output module 25 is arranged on a substrate independent of the first substrate 31, the second substrate 32, and the third substrate 33. The input / output module 25 receives signals from the outside of the robot controller 20. For example, the input / output module 25 is connected to the stop switch 101 outside the robot controller 20. The input / output module 25 has connection terminals (not shown) connected to the outside of the robot controller 20. In addition, the input / output module 25 includes a plurality of substrates. In the input / output module 25, a plurality of inputs and outputs are connected on one substrate. In addition, the input / output module 25 is connected to the second substrate 32 on which the second control unit 22 is arranged. Signals from the input / output module 25 are obtained by the second control unit 22 through being input to the second substrate 32, and are output to the first control unit 21 via the second control unit 22. Thus, signals from the input / output module 25 are obtained by the first control unit 21 and the second control unit 22 respectively.

[0027] In addition, the input / output module 25 has a first signal generation unit 25a and a second signal generation unit 25b. The first signal generation unit 25a and the second signal generation unit 25b each include, for example, an FPGA (Field Programmable Gate Array). The first signal generation unit 25a and the second signal generation unit 25b each output a signal indicating the received input signal to the second control unit 22. In the input / output module 25, the same control process is respectively executed in the first signal generation unit 25a and the second signal generation unit 25b. That is, in order to implement the safety function, the circuit structure of the input / output module 25 is made redundant. In addition, in order to implement the safety function, the input / output module 25 has a diagnostic circuit (not shown).

[0028] The communication module 26 is arranged on the first substrate 31. The communication module 26 is connected to an external device via a network. For example, the communication module 26 communicates with the PLC 102. The communication module 26 transmits and receives signals with the PLC 102 via a network such as a LAN (Local Area Network), for example. The robot controller 20 is connected to the PLC 102 via a secure communication network through the communication module 26. The communication module 26 has connection terminals for connecting to an external device via a network. In addition, the communication module 26 outputs a signal input from an external device such as the PLC 102 via the network to the first control unit 21. The signal from the communication module 26 is obtained by the first control unit 21 and output to the second control unit 22 via the first control unit 21, and thus is obtained by the first control unit 21 and the second control unit 22 respectively.

[0029] The stop switch 101 receives an input operation performed by a worker. Specifically, the stop switch 101 receives a stop operation performed by a worker to stop the operation of the robot 10. Based on the stop operation performed by the worker, the stop switch 101 outputs a stop signal for stopping the operation of the drive unit 12 to the input / output module 25 to stop the operation of the robot 10. The PLC 102 is a safety controller that communicates with the robot controller 20. Based on signals from detection devices such as a laser scanner and a light curtain, the PLC 102 outputs a stop signal for stopping the operation of the drive unit 12 to the communication module 26 via a network to stop the operation of the robot 10.

[0030] (Control during handling operation)

[0031] The first control unit 21 controls the operation of the robot 10 based on, for example, signals from an upper control device (not shown). The first control unit 21 outputs an instruction for controlling the operation of the drive unit 12 to the second control unit 22 to operate the robot arm 11 including the end effector 15. The first control unit 21 and the second control unit 22 control the operation of the robot 10 to control the handling operation of handling the workpiece W by the robot 10.

[0032] For example, the first control unit 21 acquires a signal indicating the position of the workpiece W from an upper control device (not shown) to perform a transfer operation of transferring the workpiece W by the robot 10. Based on the acquired signal, the first control unit 21 calculates the rotational speed of the servo motor 13 in the drive unit 12 for moving the end effector 15 to the position of the workpiece W. Then, the first control unit 21 outputs the calculated speed command indicating the rotational speed as a command for controlling the operation of the drive unit 12 to the second control unit 22. Based on the speed command acquired from the first control unit 21, the second control unit 22 calculates the specific current value of the current input to the drive unit 12. Then, in order to supply the current of the calculated current value to the drive unit 12, the second control unit 22 controls the switching operation of the switching element Sw by controlling the gate signal of the gate terminal of the switching element Sw input to the drive circuit unit 24. In addition, the second control unit 22 controls the currents supplied to the plurality of drive units 12 disposed on the robot arm 11 of the robot 10 based on the speed command.

[0033] (Control during operation abnormality detection)

[0034] As Figure 4 shown, when the first control unit 21, the second control unit 22, and the stop control unit 23 detect an abnormality in at least one of the operation states of the first control unit 21 and the second control unit 22 and the operation of the robot 10, that is, an operation abnormality, they perform control to stop the operation of the robot 10. In the present embodiment, the first control unit 21 and the second control unit 22 mutually monitor the operation states independently of each other and detect an abnormality in the operation of the robot 10. Moreover, when the first control unit 21 and the second control unit 22 respectively detect an abnormality in at least one of the operation states of the first control unit 21 and the second control unit 22 and the operation of the robot 10, that is, an operation abnormality, they individually output a stop command for stopping the operation of the drive unit 12 to the stop control unit 23. The stop control unit 23 stops the operation of the drive unit 12 based on the stop commands from the first control unit 21 and the second control unit 22.

[0035] In order to detect an operation abnormality, the first control unit 21 and the second control unit 22 respectively acquire common inputs from each other and execute common arithmetic processing, thereby detecting an operation abnormality. Then, when an operation abnormality is detected, the same stop command is output to the first stop control unit 23a and the second stop control unit 23b respectively. That is, in order to detect an operation abnormality, the first control unit 21 and the second control unit 22 are made redundant with each other. Then, the stop control unit 23 stops the operation of the drive unit 12 when at least one of the stop command from the first control unit 21 and the stop command from the second control unit 22 is input.

[0036] <Monitoring of Operating Range and Operating Speed>

[0037] The first control unit 21 and the second control unit 22 respectively detect the operating range and operating speed of the robot 10 as monitoring objects for detecting abnormal operations. Moreover, when the first control unit 21 and the second control unit 22 respectively detect that the robot 10 operates beyond a preset parameter range, they output a stop command. In the present embodiment, the first control unit 21 and the second control unit 22 respectively detect abnormal operations based on the position of the robot arm 11, the moving speed of the robot arm 11, the orientation of the end effector 15, and the determination of whether the robot arm 11 has stopped.

[0038] Specifically, the first control unit 21 and the second control unit 22 respectively detect the position of the robot arm 11, the moving speed of the robot arm 11, and the orientation of the end effector 15 based on the detection values from the encoder 14. Moreover, when the detected position of the robot arm 11 exceeds the preset operating range as a parameter, the first control unit 21 and the second control unit 22 respectively detect it as an abnormal operation of the robot 10. In addition, when the detected moving speed of the robot arm 11 is greater than the preset threshold speed as a parameter, the first control unit 21 and the second control unit 22 respectively detect it as an abnormal operation of the robot 10. In addition, when the detected orientation of the end effector 15 exceeds the preset range as a parameter, the first control unit 21 and the second control unit 22 respectively detect it as an abnormal operation of the robot 10. Moreover, when a command to stop the operation of the robot arm 11 has been output, and it is determined based on the detection values from the encoder 14 that the robot arm 11 has not stopped, the first control unit 21 and the second control unit 22 respectively detect it as an abnormal operation of the robot 10. When the first control unit 21 and the second control unit 22 respectively detect any one of the above abnormal operations of the robot 10, they detect an abnormal operation in the robot system 100 and thus output a stop command.

[0039] <Comparison between Detection Value and Command Value>

[0040] In addition, the first control unit 21 and the second control unit 22 respectively detect abnormal operations separately by comparing the detection value representing the rotation angle of the servo motor 13 detected by the encoder 14 with the command value based on the command for controlling the operation of the drive unit 12 output from the first control unit 21 to the second control unit 22.

[0041] The first control unit 21 obtains the ideal detected value of the encoder 14 corresponding to the instruction for controlling the operation of the drive unit 12 output to the second control unit 22 as the instruction value based on the instruction. Specifically, the first control unit 21 calculates the detected value of the encoder 14 when the servo motor 13 rotates at the rotational speed indicated by the speed instruction based on the speed instruction output to the second control unit 22 as the instruction value based on the instruction. That is, the first control unit 21 obtains the ideal detected value of the encoder 14 obtained when the operation of the robot 10 is normal as the instruction value based on the instruction. In other words, the first control unit 21 obtains the detected value of the rotational speed of the servo motor 13 calculated to output the speed instruction as the instruction value of the rotational speed based on the instruction. Further, the first control unit 21 outputs the obtained instruction value to the second control unit 22. The first control unit 21 and the second control unit 22 respectively calculate the difference between the instruction value and the detected value by comparing the obtained instruction value with the detected value from the encoder 14. Then, when the calculated difference is greater than a predetermined threshold value set as a parameter, the first control unit 21 and the second control unit 22 respectively detect an abnormal operation.

[0042] 〈Mutual monitoring of operation states〉

[0043] In addition, in the present embodiment, the first control unit 21 and the second control unit 22 mutually monitor each other's operation states. Moreover, when the monitoring result detects an abnormality in the operation state, the first control unit 21 and the second control unit 22 output a stop instruction as detecting an abnormal operation.

[0044] Specifically, the first control unit 21 and the second control unit 22 respectively calculate the position of the robot arm 11 and the moving speed of the robot arm 11 based on the detected value from the encoder 14. Then, the first control unit 21 and the second control unit 22 obtain the calculation results of the other party by mutually outputting the calculation results of the position of the robot arm 11 and the moving speed of the robot arm 11 calculated. That is, the first control unit 21 obtains the calculation result calculated by the second control unit 22, and the second control unit 22 obtains the calculation result calculated by the first control unit 21. Then, the first control unit 21 and the second control unit 22 mutually monitor the operation states by comparing their own calculation results with the calculation results of the other party obtained. When detecting an abnormal operation based on the comparison result of the calculation results, the first control unit 21 and the second control unit 22 respectively output a stop instruction.

[0045] For example, the first control unit 21 and the second control unit 22 respectively calculate the spatial position or angle and the moving speed of the flange portion for mounting the end effector 15 of the robotic arm 11 as the position of the robotic arm 11 based on the detection values from the encoder 14. The first control unit 21 and the second control unit 22 respectively obtain the difference between their calculation results as the comparison result. The first control unit 21 and the second control unit 22 respectively determine that an operation abnormality has occurred when the obtained difference is greater than a preset parameter, that is, a specified threshold value. The first control unit 21 and the second control unit 22 respectively detect an operation abnormality and output a stop instruction when it is determined that an operation abnormality has occurred based on the comparison result of the calculation results.

[0046] 〈Stop signal from outside〉

[0047] In addition, the first control unit 21 and the second control unit 22 respectively output a stop instruction based on a stop signal from outside. In the robot controller 20, the input / output module 25 receives a stop signal for stopping the operation of the drive unit 12. Specifically, the first signal generation unit 25a and the second signal generation unit 25b of the input / output module 25 respectively generate an abnormality signal indicating that an abnormality has been detected based on the stop signal received according to the stop operation of the stop switch 101. Then, the first signal generation unit 25a and the second signal generation unit 25b respectively output the abnormality signals generated for the first control unit 21 and the second control unit 22. The first control unit 21 and the second control unit 22 detect an operation abnormality and output a stop instruction when they have obtained the abnormality signals from the first signal generation unit 25a and the second signal generation unit 25b. In addition, a plurality of devices or equipment may be connected to the input / output module 25.

[0048] In addition, the first control unit 21 and the second control unit 22 respectively output a stop instruction when they have obtained a stop signal via the communication module 26. That is, the first control unit 21 and the second control unit 22 respectively output a stop instruction when they have obtained a stop signal via the communication module 26 that is separately arranged with respect to the input / output module 25. For example, the communication module 26 receives a stop signal from the PLC 102 as an external device via a network. The first control unit 21 and the second control unit 22 respectively detect an operation abnormality and output a stop instruction based on the stop signal from the PLC 102 obtained via the communication module 26.

[0049] In addition, the CPUs included in the first control unit 21 and the second control unit 22 each have a plurality of cores. Among the first control unit 21 and the second control unit 22, one core out of the plurality of cores that the CPU has performs processing for detecting an operation abnormality. Moreover, the remaining cores different from the core that performs the processing for detecting an operation abnormality perform control of the handling operation performed by the robot 10 and the like.

[0050] 〈Stopping of the operation of the drive unit implemented by the stop control unit〉

[0051] As Figure 4 shown, when the first control unit 21 and the second control unit 22 respectively detect an operation abnormality, they respectively output stop commands to the first stop control unit 23a and the second stop control unit 23b of the stop control unit 23. Then, based on the stop commands from the first control unit 21 and the second control unit 22, the first stop control unit 23a and the second stop control unit 23b respectively stop the operation of the drive circuit unit 24 that supplies power to the drive unit 12.

[0052] Specifically, in order to stop the drive circuit unit 24, the first stop control unit 23a and the second stop control unit 23b respectively stop the gate signals of the gate terminals of the switching elements Sw input to the drive circuit unit 24. The first stop control unit 23a outputs a STO1 signal (Safety Torque Off 1 signal: safety torque disconnection signal 1) that stops the operation of the switching element Sw on the upper arm side. The second stop control unit 23b outputs a STO2 signal (Safety Torque Off 2 signal: safety torque disconnection signal 2) that stops the operation of the switching element Sw on the lower arm side. In the drive circuit unit 24, the switching operations of the switching element Sw on the upper arm side and the switching element Sw on the lower arm side are respectively interrupted by the STO1 signal and the STO2 signal. That is, when the STO1 signal is output from the first stop control unit 23a, the switching operation of the switching element Sw on the upper arm side of the drive circuit unit 24 is interrupted. In addition, when the STO2 signal is output from the second stop control unit 23b, the switching operation of the switching element Sw on the lower arm side of the drive circuit unit 24 is interrupted. Thus, when at least one of the STO1 signal and the STO2 signal is obtained, the power supplied from the drive circuit unit 24 to the drive unit 12 is cut off. In this way, the stop control unit 23 is also made redundant by the first stop control unit 23a and the second stop control unit 23b.

[0053] In addition, even when the stop commands from the first control unit 21 and the second control unit 22 are not obtained, the first stop control unit 23a and the second stop control unit 23b each stop the operation of the drive unit 12 when at least one of the abnormal operation states of the first control unit 21 and the second control unit 22 and the abnormal operation of the robot 10 is detected. For example, the first stop control unit 23a and the second stop control unit 23b each monitor the signal from the first control unit 21, and when an abnormality occurs in the signal from the first control unit 21, the operation of the drive unit 12 is stopped. For example, the first stop control unit 23a and the second stop control unit 23b each monitor the signal from the first control unit 21 through a monitoring timer. When a normal signal is not input from the first control unit 21 at each specified timing, the first stop control unit 23a and the second stop control unit 23b each determine that an abnormality has occurred in the first control unit 21, and thus stop the operation of the drive unit 12.

[0054] In addition, the first stop control unit 23a and the second stop control unit 23b mutually monitor the operation states by mutually transmitting and receiving signals. Specifically, the first stop control unit 23a and the second stop control unit 23b mutually output the STO1 signal and the STO2 signal. That is, the STO1 signal from the first stop control unit 23a is acquired by the second stop control unit 23b, and the STO2 signal from the second stop control unit 23b is acquired by the first stop control unit 23a. Moreover, for example, when an abnormality such as the STO1 signal or the STO2 signal being stacked in the high-level state is detected, the first stop control unit 23a and the second stop control unit 23b each determine that an operation abnormality has been detected, and thus stop the operation of the drive unit 12.

[0055] In addition to the above, when an operation signal indicating stop is received from a stop switch (not shown) disposed on the outer surface of the housing 20a of the robot controller 20, or when an abnormality in the temperature inside the housing 20a is detected, etc., the first stop control unit 23a and the second stop control unit 23b of the stop control unit 23 also determine that an operation abnormality has been detected, and thus stop the operation of the drive unit 12.

[0056] (Control method when an abnormality in the robot system is detected)

[0057] Next, with reference to Figure 5 A control method of the robot system 100 when an operation abnormality is detected will be described. The processing of the control method of the robot system 100 when the operation abnormality is detected is executed by the first control unit 21, the second control unit 22, and the stop control unit 23.

[0058] First, in step S1, the first control unit 21 and the second control unit 22 respectively detect an abnormality in at least one of their respective operation states and the operation of the robot 10, that is, an operation abnormality. Specifically, control processing for monitoring the operation range and operation speed of the robot 10 is performed based on preset parameters stored in advance in the storage unit 31a and detection values from the encoders 14 of the respective plurality of drive units 12, control processing for comparing the detection values with command values based on commands for controlling the operation of the drive unit 12, and control processing for the first control unit 21 and the second control unit 22 to mutually monitor their operation states, to detect an operation abnormality. In addition, an operation abnormality is detected based on inputs from the input / output module 25 and the communication module 26.

[0059] Next, in step S2, the first control unit 21 and the second control unit 22 respectively output stop commands to the stop control unit 23. Specifically, the first stop control unit 23a and the second stop control unit 23b of the stop control unit 23 are respectively output the same stop commands from the first control unit 21 and the second control unit 22.

[0060] Next, in step S3, by respectively outputting a STO1 signal and a STO2 signal from the first stop control unit 23a and the second stop control unit 23b to the drive circuit unit 24, the operation of the drive unit 12 is stopped.

[0061] In addition, during the operation of the robot 10, the control processing from step S1 to step S3 is repeatedly executed at every prescribed sampling period.

[0062] [Effects of the Embodiment]

[0063] In the present embodiment, the following effects can be obtained.

[0064] In the robot system 100, the first control unit 21 and the second control unit 22 mutually monitor each other's operation states and detect abnormalities in the operation of the robot 10. When an abnormality in at least one of the operation state and the operation of the robot 10, that is, an operation abnormality, is detected, a stop instruction for stopping the operation of the drive unit 12 is output. Thus, when the operation of the robot 10 is controlled by two different control units, namely the first control unit 21 and the second control unit 22, respectively, the first control unit 21 and the second control unit 22 can mutually detect abnormalities generated in the first control unit 21 and the second control unit 22 by mutually monitoring the operation states. Therefore, the first control unit 21 and the second control unit 22, which have mutually confirmed that no abnormality has occurred, can respectively detect abnormalities in the operation of the robot 10. As a result, when the operation of the robot 10 is controlled by two different control units, abnormalities in the operation of the robot 10 can be correctly detected.

[0065] The robot system 100 includes a stop control unit 23 that is separately provided with respect to the first control unit 21 and the second control unit 22 and controls the stop of the operation of the drive unit 12. When the first control unit 21 and the second control unit 22 each detect an operation abnormality, a stop instruction is separately output to the stop control unit 23. Thus, the operation of the drive unit 12 can be stopped by the stop control unit 23 that is separately provided with respect to the first control unit 21 and the second control unit 22, based on the stop instructions respectively output from the first control unit 21 and the second control unit 22. Therefore, the operation of the drive unit 12 can be reliably stopped by the stop control unit 23 separately from the control processes of the first control unit 21 and the second control unit 22. As a result, abnormalities in the operation of the robot 10 can be correctly detected, and when an abnormality is detected, the operation of the drive unit 12 can be reliably stopped.

[0066] The robot system 100 includes a drive circuit unit 24 that supplies power to the drive unit 12. The stop control unit 23 includes a first stop control unit 23a and a second stop control unit 23b. When the first control unit 21 and the second control unit 22 respectively detect an operation abnormality, they respectively output stop commands to the first stop control unit 23a and the second stop control unit 23b, and the first stop control unit 23a and the second stop control unit 23b respectively stop the operation of the drive circuit unit 24 based on the stop commands. Thus, since the stop control unit 23 is made redundant by the first stop control unit 23a and the second stop control unit 23b, even if an abnormality occurs in either the first stop control unit 23a or the second stop control unit 23b of the stop control unit 23, the operation of the drive circuit unit 24 can be stopped by the control performed by the other party in which no abnormality has occurred, and thus the operation of the drive unit 12 can be stopped. Therefore, when an operation abnormality occurs, the operation of the drive unit 12 can be stopped more reliably.

[0067] The first stop control unit 23a and the second stop control unit 23b mutually monitor their operation states by transmitting and receiving signals to and from each other. Thus, an abnormality occurring in either the first stop control unit 23a or the second stop control unit 23b can be detected by the other party, and thus the situation where the robot 10 operates can be suppressed when an abnormality occurs in either the first stop control unit 23a or the second stop control unit 23b.

[0068] The drive unit 12 includes a servo motor 13 that rotates by being supplied with power, and an encoder 14 that detects the rotation angle of the servo motor 13. The first control unit 21 and the second control unit 22 respectively compare the detection value indicating the rotation angle of the servo motor 13 detected by the encoder 14 with the command value based on the command for controlling the operation of the drive unit 12 output from the first control unit 21 to the second control unit 22, individually detect an operation abnormality, and individually output a stop command when an operation abnormality is detected. Thus, since the first control unit 21 and the second control unit 22 that mutually monitor their operation states respectively compare the detection value indicating the rotation angle of the servo motor 13 with the command value based on the command for controlling the operation of the drive unit 12, the comparison between the detection value and the command value can be performed more reliably by the first control unit 21 and the second control unit 22 that have mutually confirmed that no abnormality has occurred. Therefore, when the operation of the robot 10 is controlled by two different control units respectively, an abnormality in the operation of the robot 10 can be detected more accurately.

[0069] The robot system 100 is provided with an input / output module 25 for receiving a stop signal for stopping the operation of the drive unit 12. The input / output module 25 includes a first signal generation unit 25a and a second signal generation unit 25b that respectively generate an abnormality signal indicating that an abnormality has been detected based on the received stop signal. The first signal generation unit 25a and the second signal generation unit 25b respectively output the abnormality signals generated for the first control unit 21 and the second control unit 22. Thus, it is possible to obtain a stop signal from an external device or an external operation unit such as a stop switch 101 via the input / output module 25. Therefore, since the first signal generation unit 25a and the second signal generation unit 25b that output the abnormality signal in the input / output module 25 are redundant, when the input / output module 25 receives a stop signal from the outside, it is possible to more reliably output the abnormality signal to the first control unit 21 and the second control unit 22. As a result, when a stop signal is received, the operation of the drive unit 12 can be stopped more reliably.

[0070] The robot system 100 is provided with a communication module 26 for inputting a stop signal for stopping the operation of the drive unit 12 from an external device. The first control unit 21 and the second control unit 22 respectively output a stop command based on the stop signal obtained via the communication module 26. Thus, since it is possible to obtain a stop signal from an external device via the communication module 26, for example, the drive unit 12 can be stopped by communicating with an external device that performs detection of intrusion into the work area of the robot 10 or detection of the locked state of a door provided in the work area. Therefore, even when other manufacturing systems or the like are combined with the robot system 100 and operated, the operation of the drive unit 12 can be reliably stopped.

[0071] The robot 10 includes a robot arm 11 having an end effector 15 mounted thereon for performing an operation. A drive unit 12 moves the robot arm 11. A first control unit 21 and a second control unit 22 respectively detect an operation abnormality based on at least two of the position of the robot arm 11, the moving speed of the robot arm 11, the orientation of the end effector 15, and the determination of whether the robot arm 11 has stopped, and output a stop instruction when an operation abnormality is detected. Thus, since the first control unit 21 and the second control unit 22 that mutually monitor the operation states respectively detect an operation abnormality based on at least two of the position of the robot arm 11, the moving speed of the robot arm 11, the orientation of the end effector 15, and the determination of whether the robot arm 11 has stopped, it is possible to more reliably detect an operation abnormality based on a plurality of determination criteria by the first control unit 21 and the second control unit 22 that have mutually confirmed a state in which no abnormality has occurred. Therefore, when controlling the operation of the robot 10 using two different control units, it is possible to more correctly detect an abnormality in the operation of the robot 10.

[0072] The drive unit 12 includes a servo motor 13 that rotates by being supplied with power, and an encoder 14 that detects the rotation angle of the servo motor 13. The robot 10 includes a robot arm 11 having an end effector 15 mounted thereon for performing an operation. The first control unit 21 and the second control unit 22 respectively calculate at least one of the position of the robot arm 11 that moves by the operation of the drive unit 12 and the moving speed of the robot arm 11 based on a detection value indicating the rotation angle of the servo motor 13 detected by the encoder 14, and obtain a calculation result of the other by mutually outputting the calculation result of at least one of the calculated position of the robot arm 11 and the moving speed of the robot arm 11, and mutually monitor the operation state by comparing the calculation result of its own with the calculation result of the other obtained, and output a stop instruction when an operation abnormality is detected based on the comparison result of the calculation results. Thus, by comparing the calculation results of both sides with each other, the first control unit 21 and the second control unit 22 can mutually monitor the operation state, and can stop the operation of the drive unit 12 when it is determined that an abnormality has occurred in either the first control unit 21 or the second control unit 22 based on the comparison result of the calculation results. Therefore, since it is possible to mutually monitor whether an abnormality has occurred in the arithmetic processing by the first control unit 21 and the second control unit 22, it is possible to more correctly detect an abnormality in the operation of the robot 10.

[0073] [Modified Example]

[0074] In addition, the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present disclosure is shown not by the description of the above embodiments but by the claims, and further includes all changes (modifications) within the meaning and scope equivalent to the scope of the claims.

[0075] For example, in the above embodiment, an example is shown in which a signal for stopping the operation of the drive unit 12 is output from the stop control unit 23 provided separately from the first control unit 21 and the second control unit 22 to the drive circuit unit 24, but the present disclosure is not limited thereto. In the present disclosure, the stop control unit may not be provided, and a signal for stopping the operation of the drive unit may be directly output from the first control unit and the second control unit to the drive circuit unit. In addition, an example is shown in which a stop instruction from the second control unit 22 is input to the stop control unit 23 via the first control unit 21, but the stop instruction may also be directly output from both the first control unit and the second control unit to the stop control unit.

[0076] In addition, in the above embodiment, an example is shown in which the stop control unit 23 is made redundant by two stop control units, i.e., the first stop control unit 23a and the second stop control unit 23b, but the present disclosure is not limited thereto. In the present disclosure, the stop control unit may not be made redundant. In addition, the stop control unit may be made redundant by three or more arithmetic devices or processing circuits.

[0077] In addition, in the above embodiment, an example is shown in which a speed command is output from the first control unit 21 to the second control unit 22, and an ideal detection value corresponding to the speed command output from the first control unit 21 is obtained as a command value based on the speed command, and an operation abnormality is detected by comparing the command value based on the speed command with the detection value of the encoder 14, but the present disclosure is not limited thereto. In the present disclosure, the command for controlling the operation of the drive unit output from the first control unit to the second control unit may not be a speed command indicating the rotational speed. The command for controlling the operation of the drive unit may be, for example, a torque command indicating the magnitude of the torque of the servo motor or a command for the rotational speed of the servo motor. In addition, an example is shown in which the command value based on the speed command is obtained by the first control unit and output to the second control unit, but the command value corresponding to the ideal detection value may also be calculated based on the command by the first control unit and the second control unit.

[0078] In addition, in the above-described embodiment, an example is shown in which a signal from the stop switch 101 is received by the input / output module 25, but the present disclosure is not limited thereto. In the present disclosure, an input may also be received from a detection device such as a laser scanner or a light curtain by the input / output module, or a switch that detects the locked state of the door portion provided in the work area of the robot. In addition, the input / output module may not be provided.

[0079] In addition, in the above-described embodiment, an example is shown in which the first control unit 21 and the second control unit 22 detect an operation abnormality based on the position of the robot arm 11, the moving speed of the robot arm 11, the orientation of the end effector 15, and the determination of whether the robot arm 11 has stopped, but the present disclosure is not limited thereto. In the present disclosure, the first control unit and the second control unit may also detect an operation abnormality based on at least two of the position of the robot arm, the moving speed of the robot arm, the orientation of the end effector, and the determination of whether the robot arm has stopped.

[0080] In addition, in the above-described embodiment, an example is shown in which the first control unit 21 and the second control unit 22 mutually output the calculation results of the position of the robot arm 11 and the moving speed of the robot arm 11 calculated by each other to obtain the calculation results of the other party, and mutually monitor the operation state by comparing the calculation results of the other party with their own calculation results, but the present disclosure is not limited thereto. In the present disclosure, the first control unit and the second control unit may also compare the calculation results of at least one of the position of the robot arm and the moving speed of the robot arm with each other to mutually monitor the operation state.

[0081] In addition, in the above-described embodiment, an example is shown in which the gate signal of the switching element Sw input to the drive circuit unit 24 is stopped to interrupt the switching operation, and the power supplied to the drive unit 12 is cut off to stop the operation of the drive unit 12, but the present disclosure is not limited thereto. In the present disclosure, the power supplied to the drive unit may also be cut off by a switch or a cut-off device such as an electromagnetic contactor to stop the operation of the drive unit.

[0082] In addition, in the above-described embodiment, an example of controlling the operation of the robot 10, which is a six-axis vertical articulated robot for transporting the workpiece W, is shown. However, the present disclosure is not limited thereto. In the present disclosure, it is also possible to control a robot that performs manufacturing or processing. In addition, the robot may be a vertical articulated robot having an axis number other than six axes, or may be a horizontal articulated robot for transporting a semiconductor substrate. In addition, instead of having a robot arm, it is also possible to control a robot that operates through a linear motion mechanism. In addition, an example of controlling the operation of the robot by inputting a signal from an upper control device to the first control unit is shown, but it is also possible to output an instruction from the first control unit to the second control unit based on preset parameters stored in the storage unit.

[0083] In addition, in the above-described embodiment, an example in which the end effector 15 attached to the end of the robot arm 11 is a robot hand that holds the workpiece W is shown. However, the present disclosure is not limited thereto. In the present disclosure, the end effector attached to the robot arm may also be a painting spray gun, a tool for screw fastening, a photographing unit, a sensor for detection, or the like. That is, the operation performed by the robot using the end effector may be not only a transportation operation, but also a painting operation, a manufacturing and assembly operation, a photographing operation, an inspection operation, or the like.

[0084] In addition, in the above-described embodiment, an example in which a signal from the input / output module 25 is input to the second control unit 22 and input to the first control unit 21 via the second control unit 22, and a signal from the communication module 26 is input to the first control unit 21 and input to the second control unit 22 via the first control unit 21 is shown. However, the present disclosure is not limited thereto. In the present disclosure, conversely, it may be configured such that a signal from the input / output module is input to the first control unit and input to the second control unit via the first control unit, and a signal from the communication module is input to the second control unit and input to the first control unit via the second control unit. In addition, it may be configured such that both the signal from the input / output module and the signal from the communication module are input to the first control unit and input to the second control unit via the first control unit, or it may be configured such that both are input to the second control unit and input to the first control unit via the second control unit. In addition, signals from the input / output module and the communication module may be directly input to both the first control unit and the second control unit.

[0085] In addition, in the above-described embodiment, an example is shown in which the first control unit 21, the second control unit 22, and the stop control unit 23 are respectively arranged on different substrates, but the present disclosure is not limited thereto. In the present disclosure, two or all of the first control unit, the second control unit, and the stop control unit may also be arranged on a common substrate. In addition, the second control unit may also be arranged respectively for each of a plurality of servo motors on a plurality of substrates. That is, a plurality of second control units may be provided in a number corresponding to the number of the plurality of servo motors.

[0086] In addition, in the above-described embodiment, an example is shown in which the first control unit 21, the second control unit 22, and the stop control unit 23 are respectively arranged in the robot controller 20, but the present disclosure is not limited thereto. In the present disclosure, the second control unit may also be arranged on the robot arm side. For example, the second control unit and the drive circuit unit may also be arranged on the robot arm. In addition, a part of the processing executed by the first control unit may also be executed by a control device such as a computer external to the robot controller.

[0087] The functions of the elements disclosed in this specification can be executed by circuitry or a processing circuit including a general-purpose processor, a dedicated processor, an integrated circuit, an ASIC (Application Specific Integrated Circuits), existing circuits, and / or a combination thereof configured or programmed to execute the disclosed functions. Since a processor includes transistors and other circuits, it is regarded as a processing circuit or circuitry. In the present disclosure, a circuit, a unit, or a means is hardware that executes the recited functions, or is hardware programmed to execute the recited functions. The hardware may be the hardware disclosed in this specification, or may also be other known hardware configured or programmed to execute the recited functions. In the case where the hardware is a processor which is regarded as a kind of circuitry, the circuit, the means, or the unit is a combination of hardware and software, and the software is for configuring the hardware and / or the processor.

[0088] For example, each of the first control unit and the second control unit may also include an arithmetic device or a processing circuit other than a CPU. In addition, each of the first stop control unit and the second stop control unit of the stop control unit may also include an arithmetic device or a processing circuit other than a CPLD. In addition, each of the first signal generation unit and the second signal generation unit of the input / output module may also include an arithmetic device or a processing circuit other than an FPGA.

[0089] [Mode]

[0090] Those skilled in the art should understand that the above exemplary embodiments are specific examples of the following modes.

[0091] (Item 1)

[0092] A robot system, comprising:

[0093] A robot;

[0094] A drive unit that serves as a drive source for operating the robot;

[0095] A first control unit that controls the operation of the robot; and

[0096] A second control unit that controls the power supplied to the drive unit based on an instruction from the first control unit,

[0097] The first control unit and the second control unit mutually monitor each other's operation states and detect abnormalities in the operation of the robot,

[0098] When an abnormality in at least one of the operation state and the operation of the robot, i.e., an operation abnormality, is detected, the first control unit and the second control unit respectively output stop instructions for stopping the operation of the drive unit.

[0099] (Item 2)

[0100] In the robot system described in Item 1,

[0101] It further includes a stop control unit that is provided separately from the first control unit and the second control unit and controls to stop the operation of the drive unit,

[0102] When the first control unit and the second control unit respectively detect the operation abnormality, they separately output the stop instructions to the stop control unit.

[0103] (Item 3)

[0104] In the robot system described in Item 2,

[0105] It further includes a drive circuit unit that supplies power to the drive unit,

[0106] The stop control unit includes a first stop control unit and a second stop control unit,

[0107] When the first control unit and the second control unit respectively detect the operation abnormality, they respectively output the stop instructions to the first stop control unit and the second stop control unit,

[0108] The first stop control unit and the second stop control unit respectively stop the operation of the drive circuit unit based on the stop instructions.

[0109] (Item 4)

[0110] In the robot system described in Item 3,

[0111] The first stop control unit and the second stop control unit mutually monitor their operation states by mutually transmitting and receiving signals to and from each other.

[0112] (Item 5)

[0113] In the robot system described in any one of Items 1 to 4,

[0114] The drive unit includes a servo motor that rotates by being supplied with power, and a rotation angle detection unit that detects the rotation angle of the servo motor.

[0115] The first control unit and the second control unit each compare a detection value indicating the rotation angle of the servo motor detected by the rotation angle detection unit with a command value based on a command for controlling the operation of the drive unit output from the first control unit to the second control unit, individually detect the operation abnormality, and output the stop command individually when the operation abnormality is detected.

[0116] (Item 6)

[0117] In the robot system described in any one of Items 1 to 5,

[0118] It further includes an input / output module for receiving a stop signal for stopping the operation of the drive unit.

[0119] The input / output module includes a first signal generation unit and a second signal generation unit that respectively generate an abnormality signal indicating that an abnormality has been detected based on the received stop signal.

[0120] The first signal generation unit and the second signal generation unit respectively output the abnormality signals generated for the first control unit and the second control unit.

[0121] (Item 7)

[0122] In the robot system described in any one of Items 1 to 6,

[0123] It further includes a communication module for inputting a stop signal for stopping the operation of the drive unit from an external device.

[0124] The first control unit and the second control unit respectively output the stop command based on the stop signal obtained via the communication module.

[0125] (Item 8)

[0126] In the robot system described in any one of Items 1 to 7,

[0127] The above-mentioned robot includes a robot arm equipped with an end effector for performing operations,

[0128] The above-mentioned drive unit moves the above-mentioned robot arm,

[0129] The above-mentioned first control unit and the above-mentioned second control unit respectively detect the above-mentioned abnormal movement based on at least two of the position of the above-mentioned robot arm, the moving speed of the above-mentioned robot arm, the orientation of the above-mentioned end effector, and the determination of whether the above-mentioned robot arm stops, and output the above-mentioned stop instruction when the above-mentioned abnormal movement is detected.

[0130] (Item 9)

[0131] In the robot system described in any one of Items 1 to 8,

[0132] The above-mentioned drive unit includes a servo motor that rotates by being supplied with power, and a rotation angle detection unit that detects the rotation angle of the above-mentioned servo motor,

[0133] The above-mentioned robot includes a robot arm equipped with an end effector for performing operations,

[0134] The above-mentioned first control unit and the above-mentioned second control unit respectively calculate at least one of the position of the above-mentioned robot arm that moves through the operation of the above-mentioned drive unit and the moving speed of the above-mentioned robot arm based on the detection value indicating the rotation angle of the above-mentioned servo motor detected by the above-mentioned rotation angle detection unit,

[0135] The above-mentioned first control unit and the above-mentioned second control unit obtain the calculation result of the other party by mutually outputting at least one of the calculation results of the position of the above-mentioned robot arm and the moving speed of the above-mentioned robot arm calculated,

[0136] The above-mentioned first control unit and the above-mentioned second control unit mutually monitor the above-mentioned operation state by comparing their own calculation results with the calculation results of the other party obtained,

[0137] The above-mentioned first control unit and the above-mentioned second control unit respectively output the above-mentioned stop instruction when the above-mentioned abnormal movement is detected based on the comparison result of the above-mentioned calculation results.

Claims

1. A robot system, characterized in that, it includes: a robot; a driving unit that serves as a driving source for operating the robot; a first control unit that controls the operation of the robot; and a second control unit that controls the power supplied to the driving unit based on an instruction from the first control unit, the first control unit and the second control unit mutually monitor each other's operation states and detect abnormalities in the operation of the robot, when detecting an abnormality in at least one of the operation state and the operation of the robot, that is, an operation abnormality, the first control unit and the second control unit respectively output stop instructions for stopping the operation of the driving unit.

2. The robot system according to claim 1, characterized in that, it further includes a stop control unit that is separately provided with respect to the first control unit and the second control unit and controls the stopping of the operation of the driving unit, when the first control unit and the second control unit respectively detect the operation abnormality, they separately output the stop instruction to the stop control unit.

3. The robot system according to claim 2, characterized in that, it further includes a drive circuit unit that supplies power to the driving unit, the stop control unit has a first stop control unit and a second stop control unit, when the first control unit and the second control unit respectively detect the operation abnormality, they respectively output the stop instruction to the first stop control unit and the second stop control unit, the first stop control unit and the second stop control unit respectively stop the operation of the drive circuit unit based on the stop instruction.

4. The robot system according to claim 3, characterized in that, the first stop control unit and the second stop control unit mutually monitor each other's operation states by mutually transmitting and receiving signals.

5. The robot system according to claim 1, characterized in that, the driving unit includes a servo motor that rotates by being supplied with power and a rotation angle detection unit that detects the rotation angle of the servo motor, the first control unit and the second control unit respectively detect the operation abnormality by comparing the detection value representing the rotation angle of the servo motor detected by the rotation angle detection unit with the instruction value based on the instruction for controlling the operation of the driving unit output from the first control unit to the second control unit, and when detecting the operation abnormality, they separately output the stop instruction.

6. The robot system according to claim 1, characterized in that, it further includes an input / output module for receiving a stop signal for stopping the operation of the driving unit, the input / output module includes a first signal generation unit and a second signal generation unit that respectively generate an abnormality signal indicating that an abnormality has been detected based on the received stop signal. The first signal generation unit and the second signal generation unit respectively output the abnormal signals generated for the first control unit and the second control unit, respectively.

7. The robot system according to claim 1, wherein, it further includes a communication module, and the communication module inputs a stop signal from an external device for stopping the operation of the driving unit, and the first control unit and the second control unit respectively output the stop instruction based on the stop signal obtained via the communication module.

8. The robot system according to claim 1, wherein, the robot includes a robot arm equipped with an end effector for performing operations, the driving unit moves the robot arm, the first control unit and the second control unit respectively detect the motion abnormality based on at least two of the position of the robot arm, the moving speed of the robot arm, the orientation of the end effector, and the determination of whether the robot arm stops, and output the stop instruction when the motion abnormality is detected.

9. The robot system according to claim 1, wherein, the driving unit includes a servo motor that rotates by being supplied with power, and a rotation angle detection unit that detects the rotation angle of the servo motor, the robot includes a robot arm equipped with an end effector for performing operations, the first control unit and the second control unit respectively calculate at least one of the position of the robot arm that moves through the operation of the driving unit and the moving speed of the robot arm based on the detection value indicating the rotation angle of the servo motor detected by the rotation angle detection unit, the first control unit and the second control unit obtain the calculation result of the other party by mutually outputting at least one of the calculation results of the position of the robot arm and the moving speed of the robot arm calculated, the first control unit and the second control unit mutually monitor the operation state by comparing their own calculation results with the calculation results of the other party obtained, and the first control unit and the second control unit respectively output the stop instruction when the motion abnormality is detected based on the comparison result of the calculation results.

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