Method and system for determining abnormalities in industrial machinery

Abstract

To accurately detect a synchronization shift in an industrial machine including a pair of driving mechanisms operating in synchronization with each other.SOLUTION: A method for determining a synchronization shift includes acquiring first driving data indicative of a dynamic state of a first driving mechanism, acquiring second driving data indicative of a dynamic state of a second driving mechanism, extracting the difference between the first driving data and the second driving data, calculating a cumulative sum of the difference, determining whether the cumulative sum has linearity or nonlinearity, and when the cumulative sum has nonlinearity, determining that a synchronization shift has occurred between the first driving mechanism and the second driving mechanism.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method and a system for determining an abnormality of industrial machinery.

Background Art

[0002] In industrial machinery, it may be required to detect the occurrence of an abnormality. Therefore, in the conventional technology, a predetermined output value of industrial machinery is detected by a sensor, and an abnormality is determined by comparing the detected output value with a threshold value (see, for example, Patent Document 1).

[0003] On the other hand, some industrial machinery includes a pair of drive mechanisms that operate in synchronization with each other. For example, Patent Document 2 discloses a work transfer device in a press line. The work transfer device includes a crossbar, a pair of swing bodies, and a pair of drive mechanisms. The pair of swing bodies are respectively connected to the left and right ends of the crossbar. The pair of drive mechanisms move the pair of swing bodies respectively.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the workpiece transfer device described above, the pair of drive mechanisms have the same structure and operate the pair of oscillating bodies in sync. However, the synchronization of the pair of drive mechanisms may become misaligned. When a misalignment occurs in the pair of drive mechanisms, it becomes difficult to operate the workpiece transfer device accurately. However, the conventional abnormality detection method described above can determine whether or not there is an abnormality in each of the pair of drive mechanisms, but it is difficult to detect a misalignment in the synchronization of the pair of drive mechanisms. The object of the present invention is to accurately detect a misalignment in synchronization in an industrial machine that includes a pair of drive mechanisms that operate in sync with each other. [Means for solving the problem]

[0006] A method according to one aspect of the present invention is a method performed by one or more computers to determine a synchronization mismatch between a first drive mechanism and a second drive mechanism in an industrial machine including a first drive mechanism and a second drive mechanism that operate synchronously with respect to each other. The method comprises: acquiring first drive data indicating the dynamic state of the first drive mechanism; acquiring second drive data indicating the dynamic state of the second drive mechanism; extracting the difference between the first drive data and the second drive data; calculating the cumulative sum of the differences; determining whether the cumulative sum is linear or nonlinear; and determining that a synchronization mismatch has occurred between the first drive mechanism and the second drive mechanism if the cumulative sum is nonlinear.

[0007] Another aspect of the present invention relates to a system for determining a synchronization mismatch between a first drive mechanism and a second drive mechanism in an industrial machine that includes a first drive mechanism and a second drive mechanism that operate synchronously with respect to each other. The system comprises a storage device and one or more computers. The storage device stores first drive data indicating the dynamic state of the first drive mechanism and second drive data indicating the dynamic state of the second drive mechanism. One or more computers are communicatively connected to the storage device. One or more computers extract the difference between the first drive data and the second drive data. One or more computers calculate the cumulative sum of the differences. One or more computers determine whether the cumulative sum is linear or nonlinear. If the cumulative sum is nonlinear, one or more computers determine that a synchronization mismatch has occurred between the first drive mechanism and the second drive mechanism. [Effects of the Invention]

[0008] According to the present invention, in an industrial machine including a pair of drive mechanisms that operate synchronously with each other, synchronization discrepancies can be detected with high accuracy. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing a predictive maintenance system according to an embodiment. [Figure 2] This is a front view of an industrial machine. [Figure 3] This is a front view showing a workpiece transport device. [Figure 4] This is a side view showing the first drive mechanism. [Figure 5] This is a flowchart showing the process for predictive maintenance services for workpiece handling equipment. [Figure 6] This is a flowchart showing the process for predictive maintenance services for workpiece handling equipment. [Figure 7A] This figure shows an example of the first drive data. [Figure 7B] This figure shows an example of the second drive data. [Figure 8]This figure shows an example of the difference data between the first drive data and the second drive data. [Figure 9A] This figure shows an example of the analysis data. [Figure 9B] This figure shows an example of a Gaussian distribution of the analyzed data. [Figure 10] This figure shows an example of cumulative sum data that demonstrates no synchronization discrepancies. [Figure 11] This figure shows an example of cumulative sum data indicating a synchronization error. [Modes for carrying out the invention]

[0010] Embodiments will be described below with reference to the drawings. Figure 1 is a schematic diagram showing a predictive maintenance system 1 according to an embodiment. The predictive maintenance system 1 is a system for determining which parts to be maintained in industrial machinery before a failure occurs. The predictive maintenance system 1 includes industrial machinery 2 and 3, a local computer 4, and a server 5.

[0011] As shown in Figure 1, industrial machines 2 and 3 include a press machine 2 and a workpiece handling device 3. Figure 2 is a front view of industrial machines 2 and 3. Press machine 2 includes a slider 11, a slide drive mechanism 12, a bolster 13, a bed 14, a die cushion device 15, and a press controller 6. The slider 11 is provided to be movable up and down. An upper die 16 is attached to the slider 11. The slide drive mechanism 12 operates the slider 11. The slide drive mechanism 12 includes, for example, a servo motor.

[0012] The bolster 13 is located below the slider 11. The lower die 17 is attached to the bolster 13. The bed 14 is located below the bolster 13. The die cushion device 15 applies an upward load to the lower die 17 during pressing. Specifically, the die cushion device 15 applies an upward load to the lower die 17 during pressing. The press controller 6 controls the operation of the slider 11 and the die cushion device 15.

[0013] The cushioning device 15 includes a cushion pad 18 and a cushioning drive mechanism 19. The cushion pad 18 is disposed below the bolster 13. The cushion pad 18 is provided so as to be movable vertically. The cushioning drive mechanism 19 moves the cushion pad 18 vertically. The cushioning drive mechanism 19 includes, for example, a servo motor.

[0014] The slide drive mechanism 12 and the cushioning drive mechanism 19 are connected to the press controller 6. The press controller 6 includes a processor and a memory (not shown). The slide drive mechanism 12 and the cushioning drive mechanism 19 are controlled by the press controller 6. Thereby, the workpiece W1 is press-worked by the upper die 16 and the lower die 17.

[0015] The workpiece transfer device 3 transfers the workpiece W1 to be press-worked. The workpiece transfer device 3 moves the workpiece W1 in the transfer direction. The transfer direction is a direction perpendicular to the plane of the drawing in FIG. 2. Hereinafter, the direction perpendicular to the plane of the drawing in FIG. 2 is defined as the front-rear direction in the workpiece transfer device 3. The left-right direction in FIG. 2 is defined as the left-right direction in the workpiece transfer device 3.

[0016] For example, the above-described press machine 2 is a part of a transfer press including a plurality of press machines, and the plurality of press machines are arranged side by side in the front-rear direction. The workpiece transfer device 3 transfers the workpiece W1 press-worked in the press machine 2 to the processing position in another press machine. As shown in FIG. 2, the workpiece transfer device 3 includes a first drive mechanism 21, a second drive mechanism 22, and a crossbar 23.

[0017] Figure 3 is a front view showing the workpiece transfer device 3. Figure 4 is a side view showing the first drive mechanism 21. As shown in Figures 3 and 4, the first drive mechanism 21 includes a first rail 31, a first linear arm 32, a first swing arm 33, and a first slider arm 34. The first rail 31 extends in the front-rear direction. The first linear arm 32 is supported by the first rail 31. As indicated by arrow A1 in Figure 4, the first linear arm 32 is movable in the front-rear direction along the first rail 31. The first swing arm 33 is connected to the first linear arm 32. As indicated by arrow A2 in Figure 4, the first swing arm 33 is swingable about a first axis Ax1 relative to the first linear arm 32. The first slider arm 34 is connected to the first swing arm 33. As indicated by arrow A3 in Figure 4, the first slider arm 34 is movable along the first swing arm 33.

[0018] The first drive mechanism 21 includes a first linear motor 35, a first swing motor 36, and a first slider motor 37. The first linear motor 35 operates the first linear arm 32. The first swing motor 36 operates the first swing arm 33. The first slider motor 37 operates the first slider arm 34. Specifically, the first linear motor 35 moves the first linear arm 32 along the first rail 31. The first swing motor 36 swings the first swing arm 33 around the first axis Ax1. The first slider motor 37 moves the first slider arm 34 along the first swing arm 33.

[0019] The second drive mechanism 22 is positioned separately from the first drive mechanism 21 in the left-right direction. The second drive mechanism 22 has a left-right symmetrical structure to the first drive mechanism 21. The second drive mechanism 22 includes a second rail 41, a second linear arm 42, a second swing arm 43, and a second slider arm 44. The second rail 41 extends in the front-rear direction. The second linear arm 42 is supported on the second rail 41. The second linear arm 42 is movable in the front-rear direction along the second rail 41. The second swing arm 43 is connected to the second linear arm 42. The second swing arm 43 is pivotable about a second axis Ax2 relative to the second linear arm 42. The second slider arm 44 is connected to the second swing arm 43. The second slider arm 44 is movable along the second swing arm 43.

[0020] The second drive mechanism 22 includes a second linear motor 45, a second swing motor 46, and a second slider motor 47. The second linear motor 45 operates the second linear arm 42. The second swing motor 46 operates the second swing arm 43. The second slider motor 47 operates the second slider arm 44. Specifically, the second linear motor 45 moves the second linear arm 42 along the second rail 41. The second swing motor 46 swings the second swing arm 43 around the second axis Ax2. The second slider motor 47 moves the second slider arm 44 along the second swing arm 43.

[0021] The crossbar 23 holds the workpiece W1. The crossbar 23 extends in the left-right direction between the first drive mechanism 21 and the second drive mechanism 22. One end of the crossbar 23 is connected to the first slider arm 34. The other end of the crossbar 23 is connected to the second slider arm 44. For example, a vacuum cup is attached to the crossbar 23 to hold the workpiece W1 by suction.

[0022] As shown in Figure 1, the workpiece transport device 3 includes a feeder controller 7. The feeder controller 7 includes a processor and memory (not shown). The motors 35-37 and 45-47 mentioned above are servo motors. The feeder controller 7 controls the motors 35-37 and 45-47 to operate the first drive mechanism 21 and the second drive mechanism 22 in a synchronous manner. More specifically, the feeder controller 7 operates the first linear motor 35 and the second linear motor 45 in a synchronous manner. The feeder controller 7 operates the first swing motor 36 and the second swing motor 46 in a synchronous manner. The feeder controller 7 operates the first slider motor 37 and the second slider motor 47 in a synchronous manner. As a result, the first drive mechanism 21 and the second drive mechanism 22 operate in a synchronous manner, and the crossbar 23 moves in the transport direction, thereby transporting the workpiece W1.

[0023] The local computer 4 communicates with the press controller 6 and the feeder controller 7. As shown in Figure 1, the local computer 4 includes a processor 51, a storage device 52, and a communication device 53. The processor 51 is, for example, a CPU (central processing unit). Alternatively, the processor 51 may be a different processor from the CPU.

[0024] The storage device 52 includes non-volatile memory such as ROM and volatile memory such as RAM. The storage device 52 may also include auxiliary storage devices such as a hard disk or an SSD (Solid State Drive). The storage device 52 is an example of a non-transitory computer-readable recording medium. The storage device 52 stores computer commands and data for controlling the local computer 4. The communication device 53 communicates with the server 5.

[0025] Server 5 collects data for predictive maintenance from the workpiece transport device 3 via the local computer 4. Based on the collected data, Server 5 performs predictive maintenance services. Server 5 communicates with the client computer 8. Server 5 provides predictive maintenance services to the client computer 8. The predictive maintenance services will be described later.

[0026] Server 5 includes a first communication device 55, a second communication device 56, a processor 57, and a storage device 58. The first communication device 55 communicates with the local computer 4. The second communication device 56 communicates with the client computer 8. The processor 57 is, for example, a CPU (central processing unit). Alternatively, the processor 57 may be a different processor from the CPU. The processor 57 performs processing for predictive maintenance services according to a program.

[0027] The storage device 58 includes non-volatile memory such as ROM and volatile memory such as RAM. The storage device 58 may also include auxiliary storage devices such as a hard disk or an SSD (Solid State Drive). The storage device 58 is an example of a non-transitory computer-readable recording medium. The storage device 58 stores computer commands and data for controlling the server 5.

[0028] The above-mentioned communication may be conducted via a mobile communication network such as 3G, 4G, or 5G. Alternatively, the communication may be conducted via other wireless communication networks such as satellite communication. Alternatively, the communication may be conducted via a computer communication network such as LAN, VPN, or the Internet. Alternatively, the communication may be conducted via a combination of these communication networks.

[0029] Next, the process for predictive maintenance services for the workpiece transfer device 3 will be described. Figures 5 and 6 are flowcharts of the process for predictive maintenance services for the workpiece transfer device 3. As shown in Figure 5, in step S101, the server 5 acquires the first drive data. The first drive data is transmitted from the feeder controller 7 to the local computer 4. The server 5 receives the first drive data from the local computer 4 and stores the first drive data in the storage device 58.

[0030] The first drive data indicates the dynamic state of the first drive mechanism 21. The first drive data includes, for example, the motor torque of the first slider motor 37. The first slider motor 37 is feedback-controlled by the feeder controller 7, and the motor torque of the first slider motor 37 is indicated, for example, by the torque command value from the feeder controller 7 to the first slider motor 37. The feeder controller 7 acquires the motor torque of the first slider motor 37 at a predetermined sampling period. The number of samples is, for example, several hundred to several thousand, but is not limited to this. The first drive data includes multiple motor torque values ​​sampled within a predetermined time.

[0031] In step S102, the server 5 acquires the second drive data. The second drive data is transmitted from the feeder controller 7 to the local computer 4. The server 5 receives the second drive data from the local computer 4 and stores it in the storage device 58. The second drive data indicates the dynamic state of the second drive mechanism 22. The second drive data includes, for example, the motor torque of the second slider motor 47. The second slider motor 47 is feedback controlled by the feeder controller 7, and the motor torque of the second slider motor 47 is indicated, for example, by the torque command value from the feeder controller 7 to the second slider motor 47.

[0032] Figure 7A shows an example of first drive data. The first drive data in Figure 7A shows the motor torque waveform of the first slider motor 37. Server 5 acquires the motor torque waveform of the first slider motor 37 as first drive data. Figure 7B shows an example of second drive data. The second drive data shown in Figure 7B shows the motor torque waveform of the second slider motor 47. Server 5 acquires the motor torque waveform of the second slider motor 47 as second drive data.

[0033] In step S103, the server 5 extracts the difference between the first drive data and the second drive data. From the first drive data and the second drive data, the server 5 extracts the difference in motor torque between the first slider motor 37 and the second slider motor 47 at the same time. The server 5 stores the extracted difference as difference data in the storage device 58. The difference data includes multiple difference values ​​of motor torque sampled within a predetermined time. Figure 8 shows an example of difference data between the first slider motor 37 and the second slider motor 47.

[0034] In step S104, Server 5 generates analysis data. Server 5 generates analysis data from the difference data using the Fast Fourier Transform. Figure 9A shows an example of analysis data. In Figure 9A, the horizontal axis is frequency and the vertical axis is amplitude. The analysis data shows the power spectrum values ​​at each frequency of the Fast Fourier Transform.

[0035] In step S105, Server 5 extracts features from the analysis data. Server 5 obtains the mean and standard deviation of the analysis data as features by transforming the analysis data into a Gaussian distribution. Figure 9B shows an example of a Gaussian distribution of the analysis data. In Figure 9B, the horizontal axis represents the random variable x and shows the power spectral value. The vertical axis represents the probability density f(x). The probability density f(x) is expressed by the following equation (1). In equation (1), "μ" is the mean and "σ" is the standard deviation. In step S106, the server 5 stores the analysis data and feature quantities μ and σ in the storage device 58. As shown in Figure 6, in step S107, the server 5 determines whether the first and second drive mechanisms 21 and 22 are functioning correctly. The server 5 determines whether the first slider motor 37 and the second slider motor 47 are functioning correctly from the feature quantities μ and σ corresponding to the difference data between the first slider motor 37 and the second slider motor 47. The determination of whether the first slider motor 37 and the second slider motor 47 are functioning correctly may be performed by known determination methods in quality engineering.

[0036] For example, Server 5 uses the MT method (Mahalanobis-Taguchi method) to determine whether the first slider motor 37 and the first slider arm 34, and the second slider motor 47 and the second slider arm 44 are functioning correctly. In this case, Server 5 calculates the Mahalanobis distance of the feature quantities μ and σ received from Server 5 based on the feature quantities μ and σ when the first slider motor 37 and the first slider arm 34, and the second slider motor 47 and the second slider arm 44 are functioning correctly. If the Mahalanobis distance is greater than a threshold, Server 5 determines that at least one of the first slider motor 37 and the first slider arm 34, and the second slider motor 47 and the second slider arm 44 is not functioning correctly. However, Server 5 may use other methods to determine whether the first and second drive mechanisms 21 and 22 are functioning correctly.

[0037] If, in step S107, the server 5 determines that the first slider motor 37 and the second slider motor 47 are not functioning correctly, the process proceeds to step S201 as shown in Figure 6. Note that the first slider motor 37 and the second slider motor 47 being "not functioning correctly" means that the first slider motor 37 and the second slider motor 47 are not yet broken, but have deteriorated to a certain extent.

[0038] In step S201, Server 5 calculates the cumulative sum of the differences. For example, Server 5 obtains the cumulative sum of the differences in motor torque between the first slider motor 37 and the second slider motor 47 from the difference data between the first slider motor 37 and the second slider motor 47 described above. Figure 10 is a diagram showing an example of cumulative sum data that represents the cumulative sum of the differences.

[0039] In step S202, Server 5 determines whether the cumulative sum is linear. Server 5 determines whether the cumulative sum is linear based on, for example, a known linearity determination method. As shown in Figures 10 and 11, Server 5 determines whether the change in the cumulative sum with respect to time is linear or nonlinear. As an indicator of linearity, for example, Server 5 may determine that there is linearity if the sum of squared residuals (RSS) between the data interpolation line and the data is 2.0 to 3.0 or less. However, the numerical value of the linearity indicator is not limited to these and may be an appropriate value depending on the model being analyzed. Figure 10 shows the cumulative sum data when there is linearity. Figure 11 shows the cumulative sum data when there is no linearity. As shown in Figure 11, if there is no linearity in the cumulative sum, in step S203, Server 5 determines that there is a synchronization mismatch between the first drive mechanism 21 and the second drive mechanism 22.

[0040] As shown in Figure 10, if the cumulative sum is not linear, in step S204, the server 5 determines that there is no synchronization mismatch between the first drive mechanism 21 and the second drive mechanism 22. Then, in step 205, the server 5 determines that deterioration is progressing in either the first drive mechanism 21 or the second drive mechanism 22.

[0041] Server 5 performs the same processing on the first drive data for the first linear motor 35 and the second drive data for the second linear motor 45 as described above. Server 5 also performs the same processing on the first drive data for the first swing motor 36 and the second drive data for the second swing motor 46 as described above. As a result, Server 5 determines whether or not there is a synchronization mismatch between the first drive mechanism 21 and the second drive mechanism 22. Server 5 also determines whether or not deterioration is progressing in either the first drive mechanism 21 or the second drive mechanism 22.

[0042] Server 5 provides the results of the above determination to client computer 8 as a predictive maintenance service. For example, Server 5 sends the determination results to client computer 8 via email. Alternatively, Server 5 may display the determination results on a management screen that can be viewed in a web browser.

[0043] In the system according to the embodiment described above, it is determined whether the cumulative sum of the differences between the first drive data and the second drive data is linear or nonlinear. If the cumulative sum is nonlinear, it is determined that a synchronization mismatch has occurred between the first drive mechanism 21 and the second drive mechanism 22. As a result, the synchronization mismatch can be detected with high accuracy in the workpiece transfer device 3, which includes the first drive mechanism 21 and the second drive mechanism 22 that operate in sync with each other.

[0044] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. For example, the processing for the predictive maintenance service described above may be performed on the press machine 2, not just the workpiece transport device 3. Alternatively, the industrial machine may include other machines such as a welding machine or a cutting machine, or workpiece transport devices used in them, not just the press machine 2 and the workpiece transport device 3.

[0045] The configuration of the workpiece transport device 3 may be changed. For example, some of the motors described above may be omitted, or motors may be added. The configuration of the server 5 may be changed. For example, the server 5 may include multiple computers. The processing performed by the server 5 described above may be distributed and executed across multiple computers. The server 5 may include multiple processors. Some or all of the processing performed by the server 5 described above may be executed by the local computer 4. For example, the processing in steps S101 to S105 described above may be executed by the local computer 4.

[0046] Some of the processes described above may be omitted or modified. The order of the processes described above may be changed. For example, the method for determining anomalies using the analysis data is not limited to that of the embodiment described above and may be changed. The features may include only one of the mean μ and standard deviation σ of the Gaussian distribution. The analysis data may be obtained not only by the Fast Fourier Transform but also by other frequency analyses such as the Discrete Fourier Transform.

[0047] The first drive data and the second drive data are not limited to the command value of the motor torque. The first drive data and the second drive data may also be other parameters that indicate the dynamic state of the first drive mechanism and the second drive mechanism, such as the motor current value, motor position, or motor rotation speed. [Industrial applicability]

[0048] According to the present invention, in an industrial machine including a pair of drive mechanisms that operate synchronously with each other, synchronization discrepancies can be detected with high accuracy. [Explanation of Symbols]

[0049] 5: Server (computer) 21: First drive mechanism 22: Second drive mechanism 23: Crossbar 34: First slider arm 37: First slider motor 44: Second slider arm 47: Second slider motor 58:Storage device

Claims

1. A method performed by one or more computers to determine a synchronization mismatch between a first drive mechanism and a second drive mechanism in an industrial machine that operates synchronously with respect to each other, To acquire first drive data indicating the dynamic state of the first drive mechanism, To acquire second drive data indicating the dynamic state of the second drive mechanism, Extracting the difference between the first drive data and the second drive data, To calculate the cumulative sum of the aforementioned differences, The determination of whether the cumulative sum is linear or nonlinear, If the cumulative sum is nonlinear, it is determined that the synchronization mismatch has occurred between the first drive mechanism and the second drive mechanism. A method for providing this.

2. By performing frequency analysis on the difference data showing the aforementioned difference, analytical data showing the power spectrum of the difference data is obtained. The Gaussian distribution of the aforementioned analysis data is determined, and features representing the Gaussian distribution are obtained. Based on the aforementioned feature quantities, determine whether the first drive mechanism and the second drive mechanism are abnormal. The method according to claim 1, further comprising:

3. Based on the aforementioned feature quantities, it is determined that the first drive mechanism and the second drive mechanism are abnormal, and if it is determined that the cumulative sum has linearity, it is determined that deterioration is progressing in either the first drive mechanism or the second drive mechanism. The method according to claim 2, further comprising:

4. The first drive mechanism includes a first motor, The second drive mechanism includes a second motor, The first drive data shows the torque waveform of the first motor. The second drive data shows the torque waveform of the second motor. The method according to claim 1.

5. The aforementioned industrial machine is a workpiece transport device that transports workpieces to be pressed. The method according to claim 1.

6. The aforementioned industrial machine is A crossbar extending between the first drive mechanism and the second drive mechanism, which holds the workpiece. Furthermore, The first drive mechanism is, A first arm connected to one end of the crossbar, A first motor for operating the first arm, Includes, The second drive mechanism is, A second arm connected to the other end of the crossbar, A second motor for operating the second arm, including, The method according to claim 5.

7. A system for determining the synchronization mismatch between a first drive mechanism and a second drive mechanism in an industrial machine that operates synchronously with respect to the first drive mechanism and the second drive mechanism, A storage device that stores first drive data indicating the dynamic state of the first drive mechanism and second drive data indicating the dynamic state of the second drive mechanism, One or more computers that are communicably connected to the aforementioned storage device, Equipped with, The one or more computers mentioned above are: The difference between the first drive data and the second drive data is extracted, The cumulative sum of the aforementioned differences is calculated, Determine whether the cumulative sum is linear or nonlinear. If the cumulative sum is nonlinear, it is determined that the synchronization mismatch has occurred between the first drive mechanism and the second drive mechanism. system.

8. The one or more computers mentioned above are: By performing frequency analysis on the difference data showing the difference, analysis data showing the power spectrum of the difference data is obtained. The Gaussian distribution of the analysis data is determined, and features representing the Gaussian distribution are obtained. Based on the aforementioned feature quantities, it is determined whether the first drive mechanism and the second drive mechanism are abnormal. The system according to claim 7.

9. The one or more computers mentioned above are: If, based on the aforementioned feature quantities, it is determined that the first drive mechanism and the second drive mechanism are abnormal, and if it is determined that the cumulative sum has linearity, then it is determined that deterioration is progressing in either the first drive mechanism or the second drive mechanism. The system according to claim 8.

10. The first drive mechanism includes a first motor, The second drive mechanism includes a second motor, The first drive data shows the torque waveform of the first motor. The second drive data shows the torque waveform of the second motor. The system according to claim 7.

11. The aforementioned industrial machine is a workpiece transport device that transports workpieces to be pressed. The system according to claim 7.

12. The aforementioned industrial machine is A crossbar extending between the first drive mechanism and the second drive mechanism, which holds the workpiece. Furthermore, The first drive mechanism is, A first arm connected to one end of the crossbar, A first motor for operating the first arm, Includes, The second drive mechanism is, A second arm connected to the other end of the crossbar, A second motor for operating the second arm, including, The system according to claim 11.

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