JP2019018270A - Abnormality determination device and abnormality determination method - Google Patents

Abstract

To identify an abnormal cause while determining abnormality of a speed reducer with high accuracy.SOLUTION: An abnormality determination device comprises: operation data acquisition means which acquires plural operation data at the time of operation of a speed reducer; evaluation value calculation means which calculates a correlation coefficient of past operation data in abnormal modes which represent forms of abnormality of the speed reducer and current operation data acquired by the operation data acquisition means in each abnormal mode, multiplies the calculated correlation coefficient and current operation data, and calculates an evaluation value in each abnormal mode by adding the multiplication result; storage means which stores a threshold for each abnormal mode; and abnormality determination means which compares a threshold in each abnormal mode which is stored by the storage means, and a corresponding evaluation value which is calculated by the evaluation value calculation means, respectively, thereby determining abnormality of the speed reducer in each abnormal mode, and identifying a possible cause of the abnormality.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an abnormality determination device and an abnormality determination method for determining an abnormality of a speed reducer of a robot.

  An abnormality determination device that determines an abnormality of a reduction gear from a command current value and rotation information of a motor with a reduction gear is known (for example, Patent Documents 1 to 5).

JP 2012-194035 A JP 2006-102889 A Japanese Patent Laid-Open No. 02-0898938 JP 2009-226488 A JP 2012-008030 A

  In the abnormality determination devices described in Patent Documents 1 to 4, abnormality can be determined, but it is not possible to individually identify the cause of the abnormality. Further, in the abnormality determination device shown in Patent Document 5, abnormality determination in an abnormal mode such as a bearing failure is performed using a vibration waveform, and the cause of the abnormality is specified. However, the vibration waveform is easily affected by disturbance, and accurate abnormality determination can be difficult.

  The present invention has been made to solve such a problem, and provides an abnormality determination device and an abnormality determination method capable of specifying the cause of an abnormality while accurately determining an abnormality of a reduction gear. The main purpose is to do.

In order to achieve the above object, one embodiment of the present invention provides:
An abnormality determination device for determining abnormality of a reduction gear provided in a robot,
Operation data acquisition means for acquiring a plurality of operation data during operation of the speed reducer;
Calculating a correlation coefficient between the past operation data in an abnormal mode indicating an abnormality mode of the speed reducer and the current operation data acquired by the operation data acquisition unit for each of the abnormal modes; An evaluation value calculation means for calculating an evaluation value for each abnormal mode by multiplying the calculated correlation coefficient and the current operation data and adding the multiplication results;
Storage means for storing a threshold value for each abnormal mode;
By comparing the threshold value of each abnormal mode stored by the storage unit and the corresponding evaluation value calculated by the evaluation value calculation unit, respectively, determine the abnormality of the speed reducer for each abnormal mode, An abnormality determining means for identifying the cause of the abnormality;
It is an abnormality determination apparatus characterized by comprising.
In this aspect, the abnormal mode includes an abnormal mode due to a foreign object in a gear in the speed reducer, an abnormal mode due to coolant intrusion in the speed reducer, an abnormal mode due to a bearing failure in the speed reducer, and a lubricating oil in the speed reducer. At least one of an abnormal mode due to deterioration of the gear and an abnormal mode due to wear of gears in the speed reducer.
In this one aspect, the operation data includes an average value of a command current value for a motor driving the reduction gear, a maximum value of the command current value, an amplitude of the command current value, a rotation speed of the motor, and the motor May include at least one of the rotation angles.
In order to achieve the above object, one embodiment of the present invention provides:
An abnormality determination method for determining an abnormality of a reduction gear provided in a robot,
Obtaining a plurality of operation data during operation of the speed reducer;
A correlation coefficient between the past operation data in the abnormal mode indicating the abnormality mode of the speed reducer and the acquired current operation data is calculated for each abnormal mode, and the calculated correlation coefficient Multiplying the current operation data and adding the multiplication result to calculate an evaluation value for each abnormal mode;
By comparing the threshold value set for each abnormal mode and the calculated corresponding evaluation value, the reduction gear abnormality is determined for each abnormal mode, and the cause of the abnormality is specified. Steps,
An abnormality determination method characterized by including:

  ADVANTAGE OF THE INVENTION According to this invention, the abnormality determination apparatus and abnormality determination method which can identify the abnormality cause can be provided, determining the abnormality of a reduction gear with high precision.

1 is a block diagram showing a schematic system configuration of a robot according to an embodiment of the present invention. 1 is a block diagram illustrating a schematic system configuration of an abnormality determination device according to an embodiment of the present invention. It is a figure which shows an example of the correlation coefficient of each operation | movement data with respect to each abnormal mode. It is a flowchart which shows the flow of the abnormality determination method by the abnormality determination apparatus which concerns on one Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a schematic system configuration of a robot according to an embodiment of the present invention. The abnormality determination device 1 according to the present embodiment is mounted on, for example, a robot 10 or the like. The abnormality determination device 1 determines an abnormality of the speed reducer 11 provided in the robot 10.

  The speed reducer 11 is provided at each joint portion (shoulder joint, wrist joint, knee joint, ankle joint, etc.) 12 of the robot 10, for example. A motor 13 is connected to the joint portion 12 via a speed reducer 11. The motor 13 rotationally drives the joint portion 12 via the speed reducer 11. The motor 13 is provided with a rotation sensor 14 that detects rotation information of the motor 13. The rotation information includes, for example, the rotation angle, rotation speed, rotation acceleration, rotation speed, and the like of the motor 13. The rotation sensor 14 is composed of, for example, an encoder or a potentiometer.

  The motor 13 and the rotation sensor 14 are connected to the control device 15. For example, the control device 15 feedback-controls the motor 13 based on rotation information detected by the rotation sensor 14. The control device 15 outputs a command current value for controlling the motor 13 to the motor 13. The motor 13 rotationally drives the joint portion 12 via the speed reducer 11 according to the command current value from the control device 15.

  By the way, although the conventional abnormality determination apparatus can perform abnormality determination, there has been a problem that it is impossible to individually identify the cause of abnormality. Even when the cause of the abnormality can be identified, accurate abnormality determination may be difficult due to the influence of disturbance or the like.

  On the other hand, the abnormality determination device 1 according to the present embodiment can identify the cause of the abnormality while determining the abnormality of the speed reducer 11 with high accuracy. The abnormality determination device 1 determines abnormality of the speed reducer 11 provided in the robot 10 based on the command current value from the control device 15 of the robot 10 and / or the rotation information from the rotation sensor 14.

  FIG. 2 is a block diagram illustrating a schematic system configuration of the abnormality determination device according to the present embodiment. The abnormality determination device 1 according to the present embodiment includes an operation data acquisition unit 2 that acquires a plurality of operation data during operation of the speed reducer 11, past operation data in an abnormality mode that indicates an abnormality mode of the speed reducer 11, and The correlation coefficient between the current motion data acquired by the motion data acquisition unit 2 is calculated for each abnormal mode, the calculated correlation coefficient is multiplied by the current motion data, and the multiplication result is added. Thus, an evaluation value calculation unit 3 that calculates an evaluation value for each abnormal mode, a storage unit 4 that stores a threshold value of each abnormal mode, a threshold value of each abnormal mode stored in the storage unit 4, and an evaluation value calculation unit The abnormality evaluation part 5 which determines the abnormality of the reduction gear 11 for every abnormality mode by each comparing with the corresponding evaluation value calculated by 3 and identifies the cause of this abnormality is provided.

  As described above, in the abnormality determination device according to the present embodiment, the correlation coefficient between the past operation data in the abnormality mode and the current operation data is calculated, and the calculated correlation coefficient is multiplied by the current operation data. Then, an evaluation value is calculated by adding the multiplication results. By comparing the evaluation value reflecting the past operation data in the actual abnormal mode and the threshold value set according to each abnormal mode, the abnormality of the speed reducer 11 is not affected by disturbance or the like. Can be determined with high accuracy. Furthermore, the cause of the abnormality can be specified by determining the abnormality of the reduction gear 11 for each abnormality mode. That is, the cause of the abnormality can be specified while determining the abnormality of the speed reducer 11 with high accuracy.

  The abnormality determination device 1 includes, for example, a CPU (Central Processing Unit) 1a that performs arithmetic processing and the like, and a ROM (Read Only Memory) and a RAM (Random Access Memory) that store arithmetic programs executed by the CPU. A hardware configuration is made up of a microcomputer including a memory 1b and an interface unit (I / F) 1c for inputting / outputting signals to / from the outside. The CPU 1a, the memory 1b, and the interface unit 1c are connected to each other via a data bus or the like.

  The motion data acquisition unit 2 is a specific example of motion data acquisition means. The operation data acquisition unit 2 acquires a plurality of operation data during the operation of the speed reducer 11 based on the command current value from the control device 15 and the rotation information from the rotation sensor 14. The operation data includes, for example, the average value of the command current value, the maximum value of the command current value, the amplitude of the command current value, the standard deviation of the command current value, the rotation speed of the motor 13, the rotation angle of the motor 13.

  For example, the operation data acquisition unit 2 calculates an average value, a maximum value, an amplitude, a standard deviation, and the like of the command current value based on the command current value output from the control device 15. Alternatively, the operation data acquisition unit 2 calculates the rotation speed, rotation angle, and the like of the motor 13 based on rotation information output from the rotation sensor 14, for example.

  The evaluation value calculation unit 3 is a specific example of evaluation value calculation means. The evaluation value calculation unit 3 is a correlation coefficient α, β, γ between the past operation data in the abnormal mode indicating the form of the abnormality of the speed reducer 11 and the current operation data acquired by the operation data acquisition unit 2. Are calculated for each abnormal mode.

  The abnormal mode includes, for example, an abnormal mode (hereinafter referred to as a gear biting mode) due to a foreign object biting of a gear in the speed reducer 11, an abnormal mode (hereinafter referred to as a coolant intrusion mode) due to intrusion of coolant (cooling water) in the speed reducer 11, An abnormal mode (hereinafter referred to as a bearing failure mode) due to a failure of the bearing in the speed reducer 11, an abnormal mode (hereinafter referred to as a lubricant deterioration mode) due to deterioration of the lubricating oil (such as grease) in the speed reducer 11, and a gear in the speed reducer 11 Including abnormal modes due to wear (hereinafter referred to as gear wear modes).

  The past operation data in each abnormal mode described above is, for example, each operation data (average value of command current value, maximum value, etc.) acquired by the operation data acquisition unit 2 until failure in each abnormal mode occurs. Amplitude, standard deviation, etc.). Past operation data in each abnormal mode is stored in the storage unit 4 or the like. The storage unit 4 is configured by, for example, the memory 1b. Past operation data in each abnormal mode may be stored in a failure record data storage unit of the cloud or server.

The evaluation value calculation unit 3 calculates the correlation coefficient of the average value of the command current value using, for example, the following equation.

In the above formula, n is the number of data, x _n is a past command current value in each abnormal mode, and x _n − is an average value of past command current values in each abnormal mode. In addition, x _n − is obtained by adding an upper bar to x _n in the above formula, and hereinafter, other parameters are similarly expressed. y _n is a current command current value acquired by the operation data acquisition unit 2, and y _n − is an average value of the current command current values acquired by the operation data acquisition unit 2. Similarly, the evaluation value calculation unit 3 may calculate the correlation coefficient of other motion data.

  FIG. 3 is a diagram showing an example of the correlation coefficient of each operation data (average value of command current value, maximum value, amplitude, standard deviation) for each abnormal mode (bearing failure mode, gear wear mode, lubricant deterioration mode). It is.

The evaluation value calculation unit 3 multiplies the calculated correlation coefficients α _m , β _m , γ _m ,... Of each abnormal mode by the corresponding current operation data acquired by the operation data acquisition unit 2. Then, the evaluation value U _m for each abnormal mode is calculated by adding the multiplication results.

For example, the evaluation value calculation unit 3 includes the correlation coefficient α _m , β _m , γ _m ,... And the operation data acquisition unit 2 in each abnormal mode m (m = 1, 2, 3,...). Are multiplied by the current operation data (average value of command current value I _m- , rotation speed V _{m of} motor 13, maximum value of command current value I _pn ,...) Is added to calculate the evaluation value U _m of each abnormal mode.
Evaluation value of abnormal mode m U _m = α _m I _m- + β _m V _m + γ _m I _pm ...

  As described above, the correlation coefficient between the past motion data actually generated in the abnormal mode and the current motion data is calculated, the calculated correlation coefficient is multiplied by the current motion data, and the multiplication is performed. An evaluation value is calculated by adding the results. Thereby, it is possible to calculate an evaluation value that is not easily affected by disturbance or the like and that accurately indicates an abnormal state of the reduction gear.

In addition, if the evaluation value is calculated by increasing the number of operation data (I _m- , V _m , I _pm ...), The correlation with the abnormality of each abnormal mode becomes stronger, and the accuracy of the evaluation value is increased. On the other hand, the calculation load increases. Therefore, in the present embodiment, it is preferable that the operation data be the average value, the maximum value, the amplitude, and the standard deviation of the command current value in consideration of the accuracy of the evaluation value and the calculation load. However, the operation data is not limited to this, and can be arbitrarily set according to the abnormal mode in which the determination is performed.

  The abnormality determination unit 5 is a specific example of an abnormality determination unit. The abnormality determination unit 5 determines the abnormality of the speed reducer 11 for each abnormality mode by comparing the threshold value of each abnormality mode with the corresponding evaluation value calculated by the evaluation value calculation unit 3, respectively. Identify the cause of

  The threshold value of each abnormal mode is stored in the storage unit 4 in advance. The storage unit 4 is a specific example of storage means. The threshold value of each abnormal mode is set in advance by experimentally obtaining the value of each evaluation value when abnormality in each abnormal mode (gear engagement, coolant intrusion, grease deterioration, etc.) has occurred. The threshold value of each abnormal mode stored in the storage unit 4 is configured so that the user can change the setting as appropriate.

  The abnormality determination unit 5 may determine abnormality including an abnormality sign of the reduction gear 11 for each abnormality mode. This abnormality sign indicates, for example, a state in which the reduction gear 11 cannot be said to be abnormal at the present time, but the abnormality occurs after several hours or after several cycles of driving. In this case, as the threshold value of each abnormal mode, for example, the value of each evaluation value when an abnormality sign of each abnormal mode occurs may be experimentally obtained and set in advance.

  The abnormality determination unit 5 determines that the abnormality in the abnormal mode is abnormal when each evaluation value calculated by the evaluation value calculation unit 3 is equal to or greater than the corresponding abnormality mode threshold. Then, the abnormality determination unit 5 identifies the abnormality of the determined abnormality mode as the cause of the abnormality of the speed reducer 11.

For example, the abnormality determining unit 5, the evaluation value U ₁ of the evaluation value calculation unit 3 gear biting mode is calculated by m = 1 is, when it becomes the corresponding abnormal mode threshold U _set1 or more, abnormal inclusive gear mesh Is determined. Then, the abnormality determination unit 5 identifies the determined abnormality of the gear biting as the cause of the abnormality of the speed reducer 11.

Likewise, abnormality determining unit 5, the evaluation value U ₂ of the calculated by the evaluation value calculation unit 3 Coolant entering mode m = 2 is, when it becomes the corresponding abnormal mode threshold U _set2 above, an abnormality of the coolant entering judge. Then, the abnormality determination unit 5 identifies the determined abnormality of coolant intrusion as the cause of the abnormality of the reduction gear 11.

  As described above, by comparing a highly accurate evaluation value reflecting past operation data in each abnormal mode with a threshold value set according to each abnormal mode, it is possible to avoid the influence of disturbance or the like. The abnormality of the speed reducer 11 can be determined with high accuracy. Furthermore, the cause of the abnormality can be specified by determining the abnormality of the reduction gear 11 for each abnormality mode. For example, the user can immediately and appropriately respond to the cause of the abnormality of the specified speed reducer 11.

  The abnormality determination unit 5 may notify the user of an abnormality determination result or abnormality cause in each abnormality mode using the notification device 6 or the like. The notification device 6 includes, for example, a display device that displays a determination result, a cause of abnormality, a light device that notifies the fact, a speaker, a communication device that remotely notifies a third party, and the like. Further, the abnormality determination unit 5 may cause the display device to display an instruction to replace the speed reducer 11 in accordance with the determination result of the abnormality in each abnormality mode.

  FIG. 4 is a flowchart showing a flow of an abnormality determination method by the abnormality determination device according to the present embodiment.

  Based on the command current value from the control device 15 and the rotation information from the rotation sensor 14, the operation data acquisition unit 2 calculates the average value, maximum value, amplitude, standard deviation, rotation speed of the motor 13, and rotation angle of the command current value. The current operation data is acquired (step S101).

  The evaluation value calculation unit 3 compares the past operation data in the abnormality mode indicating the abnormality form of the speed reducer 11 stored in the storage unit 4 and the current operation data acquired by the operation data acquisition unit 2. The number of relationships is calculated for each abnormal mode (step S102).

  The evaluation value calculation unit 3 multiplies the calculated correlation coefficient of each abnormal mode by the corresponding current operation data acquired by the operation data acquisition unit 2, and adds the multiplication result to thereby calculate the abnormal mode. Each evaluation value is calculated (step S103).

  The abnormality determination unit 5 determines the abnormality of the speed reducer 11 for each abnormality mode by comparing the threshold value of each abnormality mode with the corresponding evaluation value calculated by the evaluation value calculation unit 3, respectively. The cause is identified (step S104).

  The abnormality determination unit 5 notifies the user of the abnormality determination result and the abnormality cause in each abnormality mode using the notification device 6 or the like (step S105).

  As described above, the abnormality determination device 1 according to the present embodiment includes the operation data acquisition unit 2 that acquires a plurality of operation data during the operation of the speed reducer 11 and the past operation in the abnormality mode that indicates the form of the speed reducer 11 abnormality. The correlation coefficient between the data and the current motion data acquired by the motion data acquisition unit 2 is calculated for each abnormal mode, the calculated correlation coefficient is multiplied by the current motion data, and the multiplication result is obtained. By adding, an evaluation value calculation unit 3 that calculates an evaluation value for each abnormal mode, a storage unit 4 that stores a threshold value of each abnormal mode, a threshold value of each abnormal mode stored in the storage unit 4, and an evaluation value An abnormality determination unit 5 that determines an abnormality of the speed reducer 11 for each abnormality mode and identifies the cause of the abnormality by comparing the corresponding evaluation values calculated by the calculation unit 3 with each other. .

  Thereby, by comparing the evaluation value reflecting the past operation data in each abnormal mode with the threshold value set according to each abnormal mode, the abnormality of the speed reducer 11 is not affected by disturbance or the like. Can be determined with high accuracy. Furthermore, the cause of the abnormality can be specified by determining the abnormality of the reduction gear 11 for each abnormality mode. That is, the cause of the abnormality can be specified while determining the abnormality of the speed reducer 11 with high accuracy.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the present invention, for example, the processing shown in FIG. 4 can be realized by causing the CPU 1a to execute a computer program.

  The program may be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / W and semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)) are included.

  The program may be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

DESCRIPTION OF SYMBOLS 1 Abnormality determination apparatus, 2 Operation | movement data acquisition part, 3 Evaluation value calculation part, 3 Evaluation value calculation part, 4 Memory | storage part, 5 Abnormality determination part, 6 Notification apparatus, 10 Robot, 11 Reducer, 12 Joint part, 13 Motor, 14 Rotation sensor, 15 Control device

Claims (4)

An abnormality determination device for determining abnormality of a reduction gear provided in a robot,
Operation data acquisition means for acquiring a plurality of operation data during operation of the speed reducer;
Calculating a correlation coefficient between the past operation data in an abnormal mode indicating an abnormality mode of the speed reducer and the current operation data acquired by the operation data acquisition unit for each of the abnormal modes; An evaluation value calculation means for calculating an evaluation value for each abnormal mode by multiplying the calculated correlation coefficient and the current operation data and adding the multiplication results;
Storage means for storing a threshold value for each abnormal mode;
By comparing the threshold value of each abnormal mode stored by the storage unit and the corresponding evaluation value calculated by the evaluation value calculation unit, respectively, determine the abnormality of the speed reducer for each abnormal mode, An abnormality determining means for identifying the cause of the abnormality;
An abnormality determination device comprising: The abnormality determination device according to claim 1,
The abnormal mode is
An abnormal mode caused by a foreign object in a gear in the speed reducer, an abnormal mode caused by coolant intrusion in the speed reducer, an abnormal mode caused by a bearing failure in the speed reducer, an abnormal mode caused by deterioration of lubricating oil in the speed reducer, and the speed reduction Including at least one of abnormal modes due to wear of gears in the aircraft,
An abnormality determination device characterized by the above. The abnormality determination device according to claim 1 or 2,
The operation data includes an average value of command current values for a motor that drives the speed reducer, a maximum value of the command current value, an amplitude of the command current value, a rotation speed of the motor, and a rotation angle of the motor. Including at least one of them,
An abnormality determination device characterized by the above. An abnormality determination method for determining an abnormality of a reduction gear provided in a robot,
Obtaining a plurality of operation data during operation of the speed reducer;
A correlation coefficient between the past operation data in the abnormal mode indicating the abnormality mode of the speed reducer and the acquired current operation data is calculated for each abnormal mode, and the calculated correlation coefficient Multiplying the current operation data and adding the multiplication result to calculate an evaluation value for each abnormal mode;
By comparing the threshold value set for each abnormal mode and the calculated corresponding evaluation value, the reduction gear abnormality is determined for each abnormal mode, and the cause of the abnormality is specified. Steps,
An abnormality determination method comprising:

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