JP2009125917A - Control unit of industrial robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an industrial robot control unit 4 having a servo amplifier 5 for controlling a motor 2 for operating each articulated shaft of a robot body 1, which control unit can automatically, precisely and surely execute a failure diagnosis in the servo amplifier 5 by itself. <P>SOLUTION: The servo amplifier 5 includes: a power circuit 7 for outputting a control signal for driving the motor 2; a failure diagnosis circuit 10 for diagnosing whether the servo amplifier 5 is out of order, based on a control signal outputted from the power circuit 7; an abnormality detection circuit 8 for detecting an abnormality, based on an electric current value of the motor 2 and positional information; and a multiplexer 9. The multiplexer 9 makes a selection such that a control signal outputted from the power circuit 7 is inputted to the motor 2 when the abnormality detection circuit 8 does not detect an abnormality, and makes a selection such that a control signal outputted from the power circuit 7 is inputted to the failure diagnosis circuit 10 when the abnormality detection circuit 8 detects an abnormality. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an industrial robot control device, and more particularly to an industrial robot control device capable of diagnosing a failure of a servo amplifier in the control device.

  Conventionally, a control device for an industrial robot provided with a servo amplifier is configured as shown in FIG. 4, for example. That is, a motor 2 as a servo motor for operating each joint axis included in the robot main body 1 is connected to a servo amplifier 5 in a control device 4 for driving and controlling the motor 2 by wiring 3. The servo amplifier 5 is connected so that the controller unit 6 for controlling the servo amplifier 5 is positioned as an upper control unit. The servo amplifier 5 is provided with a power circuit unit 7 that outputs a control signal for driving the motor 2 and an abnormality detection circuit unit 8 that detects an abnormality based on a current value and position information flowing through the motor 2. .

In the abnormality detection in the abnormality detection circuit unit 8, parameters related to the operation of the robot body 1 (for example, parameters for controlling the motor 2 such as the position, speed, and current of the motor 2) are used. An abnormality display is performed by the controller unit 6 located above the amplifier 5.
JP-A-6-344293

  However, in this abnormality detection method, there is a problem that the failure detection accuracy of the servo amplifier 5 itself is poor, and further, for example, the failure of the motor 2 such as magnetic pole deterioration, the disconnection of the wiring 3 to the motor 2 or the ground fault. Even when the servo amplifier 5 itself is not broken, there is a problem that it cannot be distinguished from the failure of the servo amplifier 5. Further, in the case of this abnormality detection method, there is a problem that the operator (operator) has to guess the cause of the failure of the servo amplifier 5 by performing a trial and error on the occurrence state of the failure and checking the operation again. There is also. Furthermore, since such trial and error implementation depends largely on the experience and knowledge of the operator, the process until the cause of the failure is greatly different, so there is also a problem that it takes a lot of time to investigate the cause of the failure. .

  The failure determination process in this conventional abnormality detection method will be described with reference to the flowchart shown in FIG. FIG. 5 is a flowchart showing this conventional failure determination process. When an abnormality is detected in the servo amplifier 5 (S301), a failure diagnosis is performed by the servo amplifier 5 itself (S302), and this abnormality is displayed on the controller unit 6 to notify the operator (S303). Then, the operator investigates whether or not the servo amplifier 5 is abnormal (S304), and if the operator determines that the servo amplifier 5 is abnormal (S304Y), the operator replaces the servo amplifier 5 (S304Y). S305).

  However, in the case of other failures, for example, in the case of failure of the motor 2 or disconnection of the wiring 3 (S304N), the operator should investigate by repeating the event of occurrence of abnormality until the cause of the failure is found. The operator selects and implements (S 306) or whether to replace all the components such as the servo amplifier 5, the motor 2, and the wiring 3 (S 308) (S 307).

  Further, in this conventional abnormality detection method, an abnormality process is performed after a failure has occurred, and therefore, operations such as replacement of the servo amplifier 5 are performed after the production line is stopped. Therefore, this conventional abnormality detection method has a great influence on productivity.

  On the other hand, as a simple failure diagnosis method, a simulation waveform is generated with parameters related to the cause of failure in the controller unit 6 as a higher-level control unit of the servo amplifier 5, and the simulation waveform is compared with the failure waveform to determine the failure. A technique for inferring the cause is known (for example, Patent Document 1). However, since this method is a simulation method and is not an actual situation, it has not detected an abnormality accurately and reliably.

  The present invention has been made to solve such problems of the prior art, and provides an industrial robot control device capable of automatically and reliably performing failure diagnosis with a servo amplifier itself. The purpose is to do.

  In order to achieve such an object, the invention according to claim 1 is an industrial application having a servo amplifier that drives and controls a motor that operates each joint axis of the robot body, and a controller unit that controls the servo amplifier. In the robot control device, the servo amplifier outputs a control signal for driving the motor, and a failure diagnosis for diagnosing whether or not the servo amplifier is faulty based on the control signal output from the power circuit unit A fault diagnosis circuit unit having a process, an abnormality detection circuit unit for detecting an abnormality based on a current value flowing through the motor and position information of the motor, and the power circuit when no abnormality is detected in the abnormality detection circuit unit The control signal output from the control unit is selected to be input to the motor, and the abnormality detection circuit unit detects an abnormality. When provided the control apparatus for an industrial robot, characterized in that it comprises a multiplexer for selecting so as to input the control signal output from the power circuit unit to the fault diagnostic unit.

  According to the first aspect of the present invention, when an abnormality is detected in the abnormality detection circuit unit during the operation of the robot body, the multiplexer is switched from the motor side to the failure diagnosis circuit unit side. It is disconnected from the motor and connected to the failure diagnosis circuit unit. Therefore, when an abnormality is detected in the abnormality detection circuit unit, the operation of the motor, that is, the operation of the robot body is immediately stopped, and the failure diagnosis process in the failure diagnosis circuit unit inside the servo amplifier is executed. Will be. In the fault diagnosis process in the fault diagnosis circuit section, the control signal output from the power circuit section to the motor is normally taken into the fault diagnosis circuit section and processed in the fault diagnosis process by the switching operation by the multiplexer. It can be determined whether or not the servo amplifier itself is in failure. For example, when the output according to the command value defined by the operation program in the controller unit is not output from the power circuit unit, it can be determined that the servo amplifier itself is in failure.

Further, in the invention according to claim 2, in a control device for an industrial robot having a servo amplifier that drives and controls a motor that operates each joint axis included in the robot body, and a controller unit that controls the servo amplifier. The servo amplifier has a power circuit unit that outputs a control signal for driving a motor, and a fault diagnosis circuit that has a fault diagnosis process for diagnosing the presence or absence of a failure of the servo amplifier based on the control signal output from the power circuit unit And a multiplexer for inputting the control signal output from the power circuit unit to the failure diagnosis circuit unit when the timer included in the failure diagnosis circuit unit counts up,
There is provided an industrial robot control device characterized by comprising:

  According to the second aspect of the present invention, when the robot body is not operated, the edge between the servo amplifier and the motor is automatically cut, and the failure diagnosis process in the failure diagnosis circuit section inside the servo amplifier is entered. The internal circuit will be diagnosed. In this way, it is determined whether or not a failure may occur due to deterioration of the servo amplifier itself. In this case, since the edge of the motor wiring connected to the servo amplifier is cut, it is clear that the servo amplifier itself is abnormal when the diagnosis result is an abnormal value. When this abnormality, that is, deterioration is detected, a warning is given to the controller that there is a possibility of an abnormality, thereby prompting the operator to replace the servo amplifier. In this case, the servo amplifier is deteriorated and is not a complete failure. Considering the operation schedule of the production line including this robot system, replacing the servo amplifier during planned shutdown of the production line This can prevent productivity from being affected by shutdown.

  As described above, according to the present invention, since the servo amplifier is disconnected from the motor and wiring at the time of failure diagnosis, it is possible to automatically and reliably diagnose the failure of the servo amplifier. At the same time, it was possible to accurately determine whether the cause of the failure was in the servo amplifier. As a result, the operator's approach to maintenance after a failure is more suitable for the failure part, and the failure repair time can be made shorter than before. In addition, since it is possible to diagnose the failure deterioration of the servo amplifier, the servo amplifier can be replaced before it becomes abnormal, and the worst situation of the production line being stopped can be avoided.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a robot system including an industrial robot controller 4 having a servo amplifier 5 according to an embodiment of the present invention. The same components as those in FIG. 4 which is a block diagram showing the conventional configuration described above are denoted by the same reference numerals.

  As shown in FIG. 1, a motor 2 as a servo motor for operating each joint axis included in the robot main body 1 is connected to a servo amplifier 5 and a wiring 3 in a control device 4 for driving and controlling the motor 2. The servo amplifier 5 is connected so that the controller unit 6 that controls the servo amplifier 5 is positioned as a higher-level control unit. In the servo amplifier 5, a power circuit unit 7 for outputting a control signal for driving the motor 2 and an abnormality detection circuit unit 8 for detecting an abnormality based on the current value and position information flowing through the motor 2 are provided. Yes.

  Further, in the servo amplifier 5, a multiplexer (MUX) 9 as a switching circuit and a failure diagnosis circuit unit 10 that performs failure diagnosis of the servo amplifier 5 are provided. Further, the failure diagnosis circuit unit 10 receives a control signal (for example, a current value or a voltage value) output from the power circuit unit 7 and measures it, and based on the control signal measured by the sensor 12. A failure determination circuit 11 having a failure diagnosis process for determining whether or not an output according to the command value is output from the power circuit unit 7 is provided. The multiplexer 9 operates so that the output from the power circuit unit 7 is connected to the motor 2 via the wiring 3 and drives it during normal operation. However, when the abnormality detection circuit unit 8 detects an abnormality, the multiplexer 9 operates. Operates so that the output from the power circuit unit 7 is connected to the sensor 12 included in the failure diagnosis circuit unit 10 in response to the input of the abnormality signal from the abnormality detection circuit unit 8.

  Next, referring to FIG. 2 which is a flowchart showing a first example of the failure diagnosis process according to one embodiment of the present invention, an abnormality is detected by the abnormality detection circuit unit 8 during normal operation of the robot system. The flow of processing at that time will be described.

  When any abnormality is detected by the abnormality detection circuit unit 8 in the servo amplifier 5 (S101), the connection of the multiplexer 9 is switched to the failure diagnosis circuit unit 10 side, the connection to the motor 2 is cut off, and the edge is cut. (S102). Thereafter, the fault diagnosis circuit unit 10 operates, and the controller unit 6 instructs the power circuit unit 7 to output a basic operation pattern (for example, a constant current or pulsed current pattern). The control signal (for example, current value or voltage value) received and output from the power circuit unit 7 is measured by the sensor 12 (S103). Then, based on the measured value of the sensor 12, the failure determination circuit 11 determines whether or not the output according to the command value is output in the power circuit unit 7 (S104).

  If it is determined in S104 that the output does not correspond to the command value, it is determined that the servo amplifier 5 is faulty (S104Y), and the servo amplifier 5 is abnormal with respect to the controller unit 6. Is displayed and displayed (S105). On the other hand, if it is determined in S104 that the output is in accordance with the command value, it is determined that there is a failure other than the servo amplifier 5 (S104N), and the controller unit 6 is external to the servo amplifier 5, that is, The fact that the motor 2 or the wiring 3 is abnormal is notified and displayed (S107). If the former servo amplifier 5 is abnormal, the operator replaces the servo amplifier 5 (S106), while the latter (S108) is an abnormality outside the servo amplifier 5, that is, the motor 2 or the wiring 3. In this case, the operator replaces the motor 2 and the wiring 3.

  As described above, according to the first embodiment, when an abnormality is detected in the abnormality detection circuit unit 8 during the operation of the robot body 1, the multiplexer 9 is connected to the failure diagnosis circuit unit 10 from the motor 2 side. Therefore, the power circuit unit 7 is disconnected from the motor 2 and connected to the failure diagnosis circuit unit 10. Therefore, when an abnormality is detected in the abnormality detection circuit unit 8, the operation of the motor 2, that is, the operation of the robot body 1 is immediately stopped, and the failure in the failure diagnosis circuit unit 10 inside the servo amplifier 5 is stopped. A diagnostic process will be performed. In the fault diagnosis process in the fault diagnosis circuit unit 10, the control signal output from the power circuit unit 7 to the motor 2 is normally taken into the fault diagnosis circuit unit 10 as usual by the switching operation by the multiplexer 9. Since it is processed, it can be determined whether or not the servo amplifier 5 itself is in failure.

  The first embodiment has been described above. Although the first embodiment shows a case where an abnormality is detected during normal operation of the robot system, the present embodiment can also be applied to a case where a failure diagnosis is performed periodically. Therefore, a flow of processing when performing periodic failure diagnosis will be described with reference to FIG. 3 which is a flowchart showing a second example of the failure diagnosis process according to an embodiment of the present invention.

  The failure diagnosis circuit unit 10 has a clock (timer) for starting periodic diagnosis. Here, when this clock (timer) is timed up, that is, when the diagnosis time is reached (S201), the operation stop state of the robot 1 is confirmed (S202), and if it is stopped (S202N), the multiplexer 9 The connection is switched to the failure diagnosis circuit unit 10 side, the connection to the motor 2 is cut off, and the edge is cut (S203). Thereafter, the failure diagnosis circuit unit 10 operates, and the controller unit 6 is instructed to output a basic operation pattern (for example, a constant current or pulsed current pattern) to the power circuit unit 7. In response, a signal (for example, a current value or a voltage value) output from the power circuit unit 7 is measured by the sensor 12. And based on the measured value of the sensor 12, it is judged whether the output according to the command value is output in the power circuit unit 7 (S204). If it is determined in S204 that the output does not correspond to the command value (S205Y), it is determined that the servo amplifier 5 has failed, and the servo amplifier 5 is being deteriorated abnormally with respect to the controller unit 6. Is displayed and displayed (S206).

  As described above, according to the second embodiment, when the robot body 1 is not operated, the edge between the servo amplifier 5 and the motor 2 is automatically cut, and the failure diagnosis circuit unit 10 inside the servo amplifier 5 is cut. Then, the failure diagnosis process is started and the internal circuit of the servo amplifier 5 is diagnosed. As a result, it is determined whether or not a failure may occur due to deterioration of the servo amplifier 5 itself. In this case, since the edge with the motor 2 connected to the servo amplifier 5 is cut, it is obvious that the servo amplifier 5 itself is abnormal when the diagnosis result is an abnormal value. When this abnormality, that is, deterioration is detected, a warning is given to the controller unit 6 that there is a possibility of an abnormality, thereby prompting the operator to replace the servo amplifier 5. In this case, since the servo amplifier 5 is deteriorated and is not a complete failure, the servo amplifier 5 is replaced during a planned stop of the production line in consideration of the operation schedule of the production line including the robot system. As a result, it is possible to prevent the influence on productivity due to the suspension of operation.

  The embodiment of the present invention has been described above. According to the present embodiment, since the servo amplifier 5 is disconnected from the motor 2 and the wiring 3 at the time of failure diagnosis, the failure of the servo amplifier 5 can be automatically and reliably diagnosed. At the same time, it can be accurately determined whether or not the cause of the failure is in the servo amplifier 5. As a result, the operator's approach to maintenance after a failure is more suitable for the failure site, so that the failure repair time can be made shorter than before. In addition, since it is possible to diagnose failure deterioration of the servo amplifier 5, the servo amplifier can be replaced before it becomes abnormal, and the worst situation of the production line being stopped can be avoided.

It is a block diagram which shows the structure of the robot system containing the control apparatus 4 of the industrial robot provided with the servo amplifier 5 which concerns on one Embodiment of this invention. It is a flowchart which shows the 1st Example of the failure diagnosis process which concerns on one Embodiment of this invention. It is a flowchart which shows the 2nd Example of the failure diagnosis process which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the robot system containing the control apparatus 4 of the industrial robot provided with the conventional servo amplifier 5. FIG. It is a flowchart which shows the conventional failure diagnosis process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot main body 2 Motor 3 Wiring 4 Control apparatus 5 Servo amplifier 6 Controller part 7 Power circuit part 8 Abnormality detection circuit part 9 Multiplexer 10 Fault diagnosis circuit part 11 Failure judgment circuit 12 Sensor

Claims (2)

In a control apparatus for an industrial robot having a servo amplifier that drives and controls a motor that operates each joint axis included in the robot body, and a controller unit that controls the servo amplifier,
The servo amplifier is
A power circuit unit that outputs a control signal for driving the motor;
A failure diagnosis circuit unit having a failure diagnosis process for diagnosing the presence or absence of a failure of the servo amplifier based on the control signal output from the power circuit unit;
An abnormality detection circuit unit for detecting an abnormality based on a current value flowing through the motor and position information of the motor;
When no abnormality is detected in the abnormality detection circuit unit, the control signal output from the power circuit unit is selected to be input to the motor, and when an abnormality is detected in the abnormality detection circuit unit Is a multiplexer that selects the control signal output from the power circuit unit to be input to the fault diagnosis circuit unit;
An industrial robot control apparatus comprising: In a control apparatus for an industrial robot having a servo amplifier that drives and controls a motor that operates each joint axis included in the robot body, and a controller unit that controls the servo amplifier,
The servo amplifier is
A power circuit unit that outputs a control signal for driving the motor;
A failure diagnosis circuit unit having a failure diagnosis process for diagnosing the presence or absence of a failure of the servo amplifier based on the control signal output from the power circuit unit;
A multiplexer for inputting the control signal output from the power circuit unit to the failure diagnosis circuit unit when the timer included in the failure diagnosis circuit unit counts up;
An industrial robot control apparatus comprising:

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