JP2017094445A - Robot control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot control device capable of securing safety of an operator until a robot is completely stopped even when an abnormality occurs in a robot system.SOLUTION: A control device 20 includes: a driving section 22 in which a control signal output from a control section 26 is input via a signal transmission path and which drives a motor 41 on the basis of the input control signal; and a signal cut-off section 27 which switches the signal transmission path to either a signal passable state or a signal cut-off state. The control device 20 further includes a monitoring section 29. The monitoring section 29 performs a switching operation of the signal cut-off section 27 so that the signal transmission path is switched from the signal passable state to the signal cut-off state when detecting an abnormality in a robot system.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a robot control apparatus that constitutes a robot system including a robot having a plurality of rotating units and a motor that drives a rotating shaft of each rotating unit.

  As this type of control device, as can be seen in the following Patent Document 1, electric power is supplied from a control unit that outputs a control signal for driving control of a motor and an external power source through first to third electromagnetic contactors. A device that is configured to be operable by being supplied and includes a drive unit that drives a motor with a control signal output from the control unit as an input is known. The control unit has a function of monitoring the presence or absence of an abnormality of the robot based on position data from an encoder that detects the rotational position of the rotary shaft. A control part switches a 1st electromagnetic contactor from a conduction | electrical_connection state to a interruption | blocking state, when abnormality of a robot is detected. As a result, power supply from the external power source to the drive unit is interrupted, and the robot is stopped.

  The control device further includes a monitoring unit. The monitoring unit has a function of monitoring the presence or absence of abnormality of the robot based on the position data from the encoder. When the monitoring unit detects an abnormality of the robot, the monitoring unit switches the second and third electromagnetic contactors from the conduction state to the cutoff state. As a result, power supply from the external power source to the drive unit is interrupted, and the robot is stopped.

Japanese Patent No. 5271499

  In order to prevent an operator from entering the operation area of the robot in the production line, safety measures have been conventionally taken to enclose the operation area with a safety protection fence. In recent years, it has been considered that a robot and an operator work together in a production line in order to improve the efficiency of product production. In this case, since there is a possibility that the safety protection fence is not installed, it is necessary to take safety measures in place of the safety protection fence. In order to take this safety measure, the monitoring unit is an essential component of the control device.

  In the control device described in Patent Document 1, a power supply for the drive unit is secured in addition to the external power source such as a capacitor connected to the drive unit even when the monitoring unit switches the electromagnetic contactor to the cutoff state. It can be in the state. In this state, if an abnormality occurs in the control unit and an erroneous control signal is output from the control unit to the drive unit, the time from when the electromagnetic contactor is switched to the shut-off state until the robot is completely stopped. In some cases, the robot may perform unexpected movements. As a result, there is a risk of anxiety for the worker who works in cooperation with the robot.

  The present invention has been made to solve the above problems, and provides a robot control device that can ensure the safety of an operator until the robot is completely stopped even when an abnormality occurs in the robot system. This is the main purpose.

  1st invention comprises a robot system provided with the robot which has a some rotation part and the three-phase motor which drives the rotating shaft of each said rotation part, The robot control apparatus which drives and controls the said robot WHEREIN: The said robot A control unit that outputs a control signal for driving control, and a drive unit that inputs the control signal output from the control unit via a signal transmission path and drives the motor based on the input control signal And a signal blocking unit that switches the signal transmission path to one of a signal blocking state and a signal blocking state, and a function of monitoring the presence or absence of an abnormality of the robot system, and detecting an abnormality of the robot system, A monitoring unit that switches the signal blocking unit so as to switch the signal transmission path from the signal passable state to the signal blocking state. And wherein the door.

  In the said invention, the control signal output from the control part is input into a drive part via a signal transmission path | route. The drive unit performs drive control of the robot by driving the motor based on the input control signal.

  Here, the invention includes a signal blocking unit and a monitoring unit. The signal blocking unit switches the signal transmission path to either a signal passable state or a signal blocking state. When the monitoring unit detects an abnormality in the robot system, the monitoring unit switches the signal blocking unit so as to switch the signal transmission path from the signal passable state to the signal blocking state. According to the above invention, when an abnormality occurs in the control unit constituting the robot system, the signal blocking unit is switched to the signal blocking state by the monitoring unit. For this reason, even if an erroneous control signal is output from the control unit in a state where the power source of the driving unit is secured in addition to the external power source, the control signal is not transmitted to the driving unit. Thereby, it is possible to prevent the robot from performing an unexpected operation until the robot is completely stopped. Therefore, the safety of the operator can be ensured until the robot is completely stopped.

  In the first invention, as the drive unit, specifically, for example, as in the fifth invention, a three-phase inverter having three series connection bodies of a high side switch and a low side switch, and the series connection body A configuration including capacitors connected in parallel can be employed. In this case, the capacitor is included in a configuration that can serve as a power source for the drive unit in addition to the external power source.

  In a second aspect of the invention, the robot control device is configured so that the control unit cannot directly switch the signal blocking unit, and the control unit has a function of monitoring whether there is an abnormality in the robot, When the abnormality of the robot is detected, an instruction to switch the signal blocking unit from the signal passable state to the signal blocking state is output to the monitoring unit.

  According to the said invention, the operation | work for obtaining the certification | authentication of a 3rd party organization can be simplified about the part which concerns on the safety | security of a robot control apparatus. That is, the configuration for stopping the robot is included in the authentication target range of the third party organization. For this reason, in the control device described in Patent Document 1, when the control unit that directly switches the electromagnetic contactor is improved, it is proved that the improvement does not affect the function of safely stopping the robot by the monitoring unit. The workload can be large. On the other hand, in the above invention, the control unit cannot directly switch the signal blocking unit, and the monitoring unit directly switches the signal blocking unit. For this reason, even when the control unit is improved, it becomes easy to prove that the improvement does not affect the safe stop of the robot by the monitoring unit. Therefore, according to the said invention, when improving a control part, the operation | work for obtaining authentication can be facilitated and the workload for obtaining authentication can be reduced.

  According to a third aspect of the present invention, each of the control unit and the monitoring unit has a function of monitoring each other for the presence or absence of an abnormality. When the monitoring unit detects an abnormality of the control unit, the signal blocking unit Switching the signal blocking unit to switch from the signal passable state to the signal blocking state, and when the control unit detects an abnormality of the monitoring unit, a signal for stopping the robot as the control signal Is output to the drive unit.

  In the above invention, the robot can be stopped even when an abnormality occurs in either the monitoring unit or the control unit. Further, even when an abnormality occurs in the monitoring unit, the control unit can stop the robot with a signal for stopping the robot, instead of directly switching the signal blocking unit. Note that a signal for stopping the robot while performing a predetermined operation may be employed as the signal for stopping the robot.

  According to a fourth aspect of the present invention, the robot system includes a rotation detection unit that detects rotation position information of the rotation shaft, and the monitoring unit detects the rotation position information detected by the rotation detection unit and its command information. If the deviation is determined to be greater than or equal to a predetermined amount, it is detected that an abnormality has occurred in the robot, and when the abnormality of the robot is detected, the signal transmission path is blocked from the signal passing state to the signal cut-off state. The signal blocking unit is switched so as to switch to a state.

  In the above invention, when the monitoring unit determines that the deviation between the rotational position information detected by the rotation detecting unit and the command information has become a predetermined amount or more, the monitoring unit detects an abnormality of the robot. If an abnormality occurs in the robot, the drive control of the robot becomes impossible and the deviation becomes large. Therefore, according to the invention, the abnormality of the robot can be detected with high accuracy.

  According to a sixth aspect of the present invention, a stator winding of the motor is connected to a connection point of the high side switch and the low side switch in each phase.

  Until the robot is completely stopped, an induced voltage is generated in the stator winding due to inertial rotation of the motor. This induced voltage can be a power source for the drive unit in addition to the external power source. For this reason, if the in-phase high-side and low-side switches are simultaneously turned on by an erroneous control signal from the control unit during inertial rotation of the motor, a short-circuit current may flow.

  In this regard, in the above invention, when an abnormality occurs in the control unit, the signal blocking unit is switched to the signal blocking state by the monitoring unit. For this reason, it is possible to prevent the high-side and low-side switches having the same phase from being simultaneously turned on by an erroneous control signal from the control unit, and it is possible to prevent a short-circuit current from flowing.

The figure which shows the outline | summary of a robot system. The figure which shows the structure of a safety controller. The flowchart which shows the procedure of the process of the monitoring part which concerns on abnormality detection. The flowchart which shows the procedure of the process of the control part which concerns on abnormality detection.

  Hereinafter, an embodiment embodying a robot control device will be described with reference to the drawings. The robot according to the present embodiment is used in an assembly system such as a machine assembly factory as an industrial robot, for example.

  First, the outline of the robot system according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 1, the robot 10 constituting the robot system includes a plurality of rotating units and joints that connect the rotating units to each other. The robot 10 according to the present embodiment is configured as a 6-axis vertical articulated robot.

  The robot 10 includes a fixed portion 11 that is fixed to a floor or the like, and a first rotating portion 12 that is provided above the fixed portion 11. The arm of the robot 10 includes a lower arm 13, an upper arm 14, a wrist portion 15, and a hand portion 16 in addition to the first rotating portion 12. The 1st rotation part 12 is equivalent to the root part on the opposite side to the arm tip part among the both ends of an arm. The first rotating unit 12 is rotatable in the horizontal direction with a first axis J1 extending in the vertical direction as a rotation center.

  The first rotating portion 12 is connected to the lower end portion of the lower arm 13 as the second rotating portion so as to be rotatable clockwise or counterclockwise about a second axis J2 extending in the horizontal direction as a rotation center. . The upper arm 14 is coupled to the upper end of the lower arm 13 so as to be rotatable clockwise or counterclockwise about a third axis J3 extending in the horizontal direction. The upper arm 14 is configured to be divided into two arm portions on the base end side (the joint side having the third axis J3 as the rotation center during rotation) and the tip end side, and the base end side is the third rotation. The first upper arm 14A (third rotating part) as a part, and the tip side is a second upper arm 14B (fourth rotating part) as a fourth rotating part. The second upper arm 14B is rotatable in the torsional direction with respect to the first upper arm 14A, with a fourth axis J4 extending in the longitudinal direction of the upper arm 14 as a rotation center.

  A wrist portion 15 as a fifth rotating portion is provided at the distal end portion of the second upper arm 14B. The wrist portion 15 is rotatable with respect to the second upper arm 14B with a fifth axis J5 extending in the horizontal direction as a rotation center. A hand portion 16 as a sixth rotating portion for attaching a work, a tool, or the like is provided at the distal end portion of the wrist portion 15. The hand portion 16 is rotatable in the torsional direction with the sixth axis J6 that is the center line as the rotation center. A TCP (Tool Center Point) that is the center point 16a of the hand unit 16 is set as a control point.

  Each rotating part of the robot 10 is driven by a motor 41 (see FIG. 2) provided correspondingly. The motor 41 can rotate in both forward and reverse directions, and each rotating unit is driven by the drive of the motor 41 with reference to the origin position.

  The robot system further includes a controller 20 that controls the robot 10 and a teaching pendant 30 that is electrically connected to the controller 20. The teaching pendant 30 includes a microcomputer including a CPU, ROM, and RAM, various manual operation keys, a display, and the like. The pendant 30 can communicate with the controller 20. The operator can manually operate the pendant 30 to create, modify, register, and set various parameters for the operation program of the robot 10. In teaching for correcting an operation program or the like, a teaching point through which a TCP as a control point passes in the work is taught. The operator can operate the robot 10 through the controller 20 based on the teaching operation program.

  Next, the electrical configuration of the robot system will be described with reference to FIG.

  The controller 20 includes a rectifier 21 that converts an AC voltage output from an external power supply 40 (commercial power supply) into a DC voltage, and a drive unit 22 that is supplied with the DC voltage output from the rectifier 21. The drive unit 22 smoothes the DC voltage output from the rectifier 21, converts the DC voltage output from the capacitor 23 into an AC voltage, and applies it to the stator windings 41 U, 41 V, 41 W of the motor 41. The three-phase inverter 24 is provided. The motor 41 and the inverter 24 are individually provided corresponding to each rotating part of the robot 10.

  The inverter 24 includes three series-connected bodies of a high side switch SWH and a low side switch SWL. The capacitor 23 is connected in parallel to these series connection bodies. A first end of a U-phase stator winding 41U is connected to a connection point between the U-phase high-side and low-side switches SWH and SWL. A first end of a V-phase stator winding 41V is connected to a connection point between the V-phase high-side and low-side switches SWH and SWL. A first end of a W-phase stator winding 41W is connected to a connection point of the W-phase high-side and low-side switches SWH and SWL. The second ends of the stator windings 41U, 41V, 41W are connected to each other at a neutral point. Incidentally, in this embodiment, voltage controlled semiconductor switching elements are used as the switches SWH and SWL, and more specifically, IGBTs are used. The freewheel diodes DH and DL are connected in antiparallel to the switches SWH and SWL. In the present embodiment, a permanent magnet synchronous machine is used as the motor 41 having the stator windings 41U, 41V, 41W.

  The controller 20 includes a power cutoff unit 25 provided on an electrical path connecting the external power source 40 and the drive unit 22. In the present embodiment, a contactor (electromagnetic contactor) is used as the power cutoff unit 25. The power shut-off unit 25 electrically connects the external power source 40 and the drive unit 22 when the connection state is made conductive, and drives with the external power source 40 when the connection state is made the cut-off state. Electrical isolation from the part 22 is made.

  The controller 20 includes a control unit 26 that performs drive control of the motor 41. The control unit 26 is configured mainly with a microprocessor, and is configured to be able to acquire an output signal of an encoder 42 as a rotation detection unit that detects rotation position information of the motor 41. The encoder 42 is provided individually corresponding to each motor 41. The control unit 26 is a PWM signal that is a control signal for driving the high-side and low-side switches SWH and SWL so as to control the control amount (for example, rotation speed) of the motor 41 provided corresponding to each rotation axis to the command value. Is output to the inverter 24.

  The controller 20 includes a signal blocking unit 27. The signal blocking unit 27 is provided on a signal transmission path for PWM signal transmission that connects the control unit 26 and the inverter 24. The signal blocking unit 27 includes a buffer IC 27a (for example, a three-state buffer) provided on the signal transmission path and a switch 27b. The switch 27b switches an electrical connection state between the power supply 28 and the buffer IC 27a to either a conduction state or a cutoff state by being energized. When the switch 27b is turned on, the signal transmission path is in a signal passable state. As a result, the PWM signal output from the control unit 26 is transmitted to the inverter 24 via the buffer IC 27a. On the other hand, the signal transmission path is set to the signal cutoff state by setting the switch 27b to the cutoff state. As a result, the PWM signal output from the control unit 26 cannot pass through the buffer IC 27 a, and the PWM signal is not transmitted to the inverter 24. As a result, all the high-side and low-side switches SWH and SWL constituting the inverter 24 are turned off.

  The controller 20 includes a monitoring unit 29 that monitors whether the robot 10 and the control unit 26 are abnormal. The monitoring unit 29 is configured to be able to acquire the output signal of the encoder 42. In the present embodiment, each of the control unit 26 and the monitoring unit 29 has a function of monitoring each other for the presence or absence of abnormality. In the present embodiment, only the monitoring unit 29 in the controller 20 can directly switch the signal cutoff unit 27 and the power cutoff unit 25. For this reason, the control unit 26 cannot directly switch the signal cutoff unit 27 and the power cutoff unit 25. That is, the control unit 26 and the power cutoff unit 25 are not directly connected by a signal line, and the control unit 26 and the signal cutoff unit 27 are not directly connected so as to be operable by the signal line.

  In the present embodiment, the control unit 26, the monitoring unit 29, the power cutoff unit 25, the drive unit 22, and the signal cutoff unit 27 are accommodated in a common casing 20a.

  Subsequently, processing of the monitoring unit 29 and the control unit 26 relating to abnormality detection will be described.

  First, the processing of the monitoring unit 29 will be described with reference to FIG. This process is repeatedly executed by the monitoring unit 29 at a predetermined cycle, for example.

  In this series of processing, first, in step S10, it is determined whether or not an abnormality has been detected in at least one of the robot 10 and the control unit 26. Hereinafter, the abnormality detection methods of the robot 10 and the control unit 26 will be described.

  The abnormality detection method of the robot 10 will be described. In this embodiment, when it is determined that the deviation between the rotation angle of the rotation axis based on the rotation position information detected by the encoder 42 and the command angle thereof is a predetermined amount or more, the robot It is determined that 10 abnormalities are detected. The command angle is, for example, a command rotation angle of each rotation axis determined by PTP control when the drive control of the robot 10 is performed by PTP control, and is controlled when the drive control is performed by CP control. It is a rotation angle of each rotation axis calculated by performing an inverse conversion process on the command value of the point.

  On the other hand, an abnormality detection method of the control unit 26 will be described. In the present embodiment, an abnormality of the control unit 26 is detected based on a watchdog timer.

  When it determines with abnormality being detected in step S10, it progresses to step S11 and switches the switch 27b from a conduction | electrical_connection state to a interruption | blocking state. As a result, the signal blocking unit 27 is switched from the signal passable state to the signal blocking state. Further, the power shut-off unit 25 is switched from the conductive state to the shut-off state. Thereby, the power supply from the external power supply 40 to the drive unit 22 is interrupted.

  Next, processing of the control unit 26 will be described with reference to FIG. This process is repeatedly executed by the control unit 26 at a predetermined cycle, for example.

  In this series of processes, it is first determined in step S20 whether or not an abnormality of the robot 10 has been detected. Here, the abnormality detection method of the robot 10 may be the same method as the method described in step S10 of FIG.

  If it is determined in step S20 that an abnormality has been detected, the process proceeds to step S21. In step S21, an instruction to switch the signal blocking unit 27 from the signal passable state to the signal blocking state and an instruction to switch the power supply blocking unit 25 from the conducting state to the blocking state are output to the monitoring unit 29. Thereby, the monitoring unit 29 switches the signal blocking unit 27 to the signal blocking state, and switches the power blocking unit 25 to the blocking state.

  On the other hand, if a negative determination is made in step S20, the process proceeds to step S22 to determine whether or not an abnormality of the monitoring unit 29 has been detected. In the present embodiment, an abnormality of the monitoring unit 29 is detected based on the watchdog timer.

  If it is determined in step S22 that an abnormality has been detected, the process proceeds to step S23, and the output of the PWM signal to the inverter 24 is stopped. Thereby, the drive control of the robot 10 is stopped.

  The embodiment described in detail above has the following advantages.

  The controller 20 includes a signal blocking unit 27 and a monitoring unit 29. When the monitoring unit 29 detects an abnormality in at least one of the robot 10 and the control unit 26, the monitoring unit 29 switches the switch 27b from the conduction state to the cutoff state. For this reason, when an abnormality occurs in the control unit 26, the signal blocking unit 27 is switched to the signal blocking state by the monitoring unit 29. As a result, even if an incorrect PWM signal is output from the control unit 26, the PWM signal is not transmitted to the inverter 24. Therefore, it is possible to prevent the robot 10 from performing an unexpected operation until the robot 10 is completely stopped. Therefore, the operator's safety can be ensured until the robot 10 is completely stopped.

  Further, when the monitoring unit 29 switches the signal blocking unit 27 to the signal blocking state, the high-side and low-side switches SWH and SWL having the same phase due to an erroneous PWM signal from the control unit 26 until the robot 10 is completely stopped. Can be prevented from being turned on simultaneously. Thereby, it is possible to prevent a short-circuit current from flowing through the inverter 24 due to the induced voltage generated in the stator windings 41U, 41V, 41W.

  In the controller 20, the controller 20 is configured such that only the monitoring unit 29 can switch the signal blocking unit 27. Thereby, about the part which concerns on the safety | security of the controller 20, the operation | work for obtaining the certification | authentication of a third party organization can be made easy. That is, a configuration for stopping the robot 10 is included in the authentication target range of the third party organization. In the present embodiment, the control unit 26 cannot directly switch the signal blocking unit 27, and the monitoring unit 29 directly switches the signal blocking unit 27. For this reason, even if the control unit 26 is improved, the improvement does not affect the monitoring unit 29 that switches the signal blocking unit 27. Therefore, according to the present embodiment, when the control unit 26 is improved, the work for obtaining authentication can be facilitated, and the work load for obtaining authentication can be reduced.

  When each of the monitoring unit 29 and the control unit 26 determines that the deviation between the rotation angle calculated based on the rotation position information of the encoder 42 and the command angle is a predetermined amount or more, an abnormality has occurred in the robot 10. Detected. This detection method is a highly reliable abnormality detection method because the rotation angle of each rotation axis is a parameter that can accurately grasp the operation state of each rotation unit of the robot 10. For this reason, in this embodiment, it is possible to accurately detect that an abnormality has occurred in the robot 10. Thereby, the condition which should switch the signal interruption | blocking part 27 to a signal interruption | blocking state can be grasped | ascertained exactly.

  Each of the control unit 26 and the monitoring unit 29 has a function of monitoring whether or not there is an abnormality. When detecting an abnormality in the control unit 26, the monitoring unit 29 switches the power cut-off unit 25 to the cut-off state, and switches the signal cut-off unit 27 to the signal cut-off state. For this reason, the means for stopping the robot 10 can be doubled. Further, when the control unit 26 detects an abnormality in the monitoring unit 29, the control unit 26 stops outputting the PWM signal to the inverter 24. As a result, the robot 10 can be stopped regardless of whether the monitoring unit 29 or the control unit 26 has an abnormality.

(Other embodiments)
In addition, the said embodiment can also be changed and implemented as follows.

  In the above embodiment, the abnormality detection target by the control unit 26 and the monitoring unit 29 may include other components of the robot system such as the power shut-off unit 25 in addition to the robot 10.

  The abnormality detection method for the robot 10 by the control unit 26 and the monitoring unit 29 is not limited to that shown in the above embodiment. For example, when it is determined that the current control point calculated based on the rotational position information has deviated from a predetermined operating range, or when the rotational speed of the current rotational axis calculated based on the rotational position information is greater than or equal to a specified speed. If determined, an abnormality of the robot 10 may be detected.

  When a positive determination is made in step S22 of FIG. 4, a PWM signal that stops the robot 10 while applying a dynamic brake to the robot 10 may be output. The dynamic brake is to decelerate and stop the motor 41 by operating the inverter 24 so as to form a closed circuit including the stator windings 41U, 41V, 41W and a switch of the inverter 24.

  In addition, when an affirmative determination is made in step S <b> 22 of FIG. 4, a PWM signal that stops the robot 10 while causing the robot 10 to perform an operation such that the rotating unit of the robot 10 moves away from the operator may be output. Specifically, for example, a PWM signal for stopping the robot 10 is output while turning the first rotating unit 12 around the first axis J1 so that the center point 16a of the robot 10 is separated from a predetermined operator's work space. do it. Information relating to the work space of the worker is stored in advance in the memory of the controller 20, for example.

  In the above embodiment, when detecting an abnormality of the robot 10, the control unit 26 may not output an instruction to switch the connection state of the power shutoff unit 25 from the conduction state to the cutoff state to the monitoring unit 29.

  In the above embodiment, the monitoring unit 29 may not switch the connection state of the power shut-off unit 25 to the shut-off state when detecting an abnormality in at least one of the robot 10 and the control unit 26.

  In the above embodiment, a power cutoff unit that is directly switched by the control unit 26 may be further provided on the electrical path connecting the external power source 40 and the drive unit 22. That is, a power cutoff unit may be provided individually corresponding to each of the monitoring unit 29 and the control unit 26.

  The power cutoff unit 25 is not limited to a contactor, and may be a semiconductor switch such as an IGBT. Further, the power shut-off unit 25 is not an essential component for the controller 20.

  In the above embodiment, the drive unit 22 and the power cutoff unit 25 may not be accommodated in the common casing 20a, and at least the control unit 26, the monitoring unit 29, and the signal cutoff unit 27 are accommodated in the casing 20a. Just do it.

  The robot is not limited to a vertical articulated type, but may be a horizontal articulated type, for example.

  DESCRIPTION OF SYMBOLS 10 ... Robot, 20 ... Controller, 22 ... Drive part, 25 ... Power supply interruption | blocking part, 26 ... Control part, 27 ... Signal interruption | blocking part, 29 ... Monitoring part, 41 ... Motor.

Claims (6)

In a robot control device comprising a robot having a plurality of rotating units and a three-phase motor that drives a rotation axis of each rotating unit, and driving and controlling the robot,
A control unit for outputting a control signal for driving control of the robot;
The control signal output from the control unit is input via a signal transmission path, and a drive unit that drives the motor based on the input control signal;
A signal blocking unit that switches the signal transmission path to either a signal passing state or a signal blocking state;
The function of monitoring the presence or absence of an abnormality in the robot system, and when the abnormality of the robot system is detected, the signal blocking unit is switched to switch the signal transmission path from the signal passable state to the signal blocking state. A robot control device comprising: a monitoring unit that operates. The robot control device is configured so that the control unit cannot directly switch the signal blocking unit,
The control unit has a function of monitoring the presence or absence of an abnormality of the robot, and when the abnormality of the robot is detected, an instruction to switch the signal blocking unit from the signal passable state to the signal blocking state is the monitoring unit The robot control apparatus according to claim 1, wherein Each of the control unit and the monitoring unit has a function of monitoring each other for the presence or absence of an abnormality,
When the monitoring unit detects an abnormality of the control unit, the monitoring unit switches the signal blocking unit to switch the signal blocking unit from the signal passable state to the signal blocking state,
The robot control device according to claim 2, wherein the control unit outputs a signal for stopping the robot to the driving unit as the control signal when detecting an abnormality of the monitoring unit. The robot system includes a rotation detection unit that detects rotation position information of the rotation shaft,
When the monitoring unit determines that the deviation between the rotation position information detected by the rotation detection unit and the command information is a predetermined amount or more, the monitoring unit detects that an abnormality has occurred in the robot, and the robot 4. The robot control device according to claim 1, wherein when the abnormality is detected, the signal blocking unit is switched to switch the signal transmission path from the signal passable state to the signal blocking state. 5. .   The said drive part contains the three-phase inverter which has three series connection bodies of a high side switch and a low side switch, and the capacitor | condenser connected in parallel with the said series connection body of any one of Claims 1-4. Robot control device.   The robot control device according to claim 5, wherein a stator winding of the motor is connected to a connection point of the high-side switch and the low-side switch in each phase.

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