Transmission monitoring system

Abstract

This invention provides a transmission device monitoring system capable of determining the vibration frequency for diagnosing the transmission device based on motor-related current information that is a composite superposition of mechanical and electrical noise. It includes: a diagnostic frequency estimation unit (8) that uses at least the current information related to the motor (4), the gear ratio of the transmission device (5), and the number of gears in the transmission device (5) to extract multiple diagnostic frequency candidate groups from a frequency region at least a certain frequency (Δf) apart, and estimates a frequency satisfying a specific relationship from the frequencies obtained from the multiple diagnostic frequency candidate groups as the diagnostic frequency; and an anomaly diagnosis unit (15) that uses at least one diagnostic frequency estimated by the diagnostic frequency estimation unit (8) to diagnose anomalies in the transmission device (5).

Description

Technical Field

[0001] This invention relates to a transmission monitoring system for monitoring a motor-driven transmission. Background Technology

[0002] In recent years, the expansion of the Internet of Things (IoT), the advancement of AI (Artificial Intelligence), and the shrinking labor force have combined to generate interest in technologies that automatically diagnose anomalies in mechanical devices based on information obtained from sensors. Among these, diagnostic techniques utilizing vibration sensors to detect vibrations generated when anomalies occur have been disclosed for motor-driven devices. A representative method is one that diagnoses anomalies in rotating components such as bearings and gears by monitoring increases in the inherent vibration frequency components (amplitude) of the parts. This method can infer the state of the anomaly by observing increases or decreases in the frequency components and can also pinpoint the location of the anomaly corresponding to each frequency.

[0003] At this point, determining the vibration frequency is crucial, especially in systems with transmissions, where the vibration frequencies of all shafts / rotating components before and after the gear shift need to be determined. However, in most cases, the mechanical specifications (design specifications) used to determine these frequencies are not publicly available. Furthermore, even if the mechanical specifications are available, it can be difficult to detect specific frequencies in environments where vibrations from other machinery, such as those from the machine being diagnosed, are ubiquitous. Therefore, issues such as the time required for frequency determination or the selection of the wrong frequency arise.

[0004] Therefore, Patent Document 1 discloses a method for determining the vibration frequencies of each rotating shaft / component before and after a gear shift, even in complex machines including transmissions, even without specification information. Specifically, using the predicted value of the meshing frequency of the gears included in the transmission and the maximum peak value (amplitude) within the range of the predicted value of that frequency, the method determines, for example, the meshing frequency used to diagnose gear abnormalities, the number of teeth on the gears (if the number of teeth is known, the reduction ratio and the rotational speed of each shaft can also be calculated).

[0005] Existing technical documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-181282 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, the technology described in Patent Document 1 can be applied to situations using vibration sensors, but it is not suitable for diagnostic methods using current sensors that can diagnose rotating parts in the same way as vibration sensors.

[0009] The reason is that electrical noise (vibration) is superimposed on the mechanical vibration component in the motor current. It is a well-known fact that mechanical vibration components generated during abnormalities are also superimposed on the motor current. Electrical noise includes, for example, high-order harmonics generated when driving a motor (AC motor). Furthermore, there are cases where the peak value (amplitude) of the electrical noise is larger than that of the mechanical vibration. Therefore, in methods that use maximum peak value search, such as in Patent Document 1, it is difficult to determine the mechanical vibration frequency (diagnostic frequency) used for abnormality diagnosis.

[0010] The present invention was made in view of the above situation, and the object of the present invention is to determine the vibration frequency of the rotating parts of the transmission device for diagnosing abnormalities based on the motor-related current information, which is a composite superposition of mechanical vibration and electrical vibration.

[0011] Methods for solving problems

[0012] To address the aforementioned issues, one aspect of the present invention provides a transmission monitoring system for monitoring a motor-driven transmission, comprising: a diagnostic frequency estimation unit that uses at least current information related to the motor, the transmission ratio, and the number of stages of the transmission to extract multiple candidate diagnostic frequencies from a frequency region at least a certain frequency apart, and estimates a frequency satisfying a specific relationship from the frequencies obtained from the multiple candidate diagnostic frequencies as a diagnostic frequency; and an anomaly diagnosis unit that uses at least one diagnostic frequency estimated by the diagnostic frequency estimation unit to diagnose anomalies in the transmission.

[0013] Invention Effects

[0014] According to at least one aspect of the present invention, it is possible to accurately and automatically estimate the vibration frequency component for diagnosing abnormalities in rotating components of a transmission device based on motor-related current information that is a composite superposition of mechanical and electrical vibrations. Furthermore, by using this diagnostic frequency component, improvements in diagnostic accuracy and reductions in the time required to construct the transmission device monitoring system can be expected.

[0015] Other issues, structures, and effects not mentioned above become clear through the following description of implementation methods. Attached Figure Description

[0016] Figure 1 This is a block diagram illustrating a structural example of a transmission device monitoring system according to the first embodiment of the present invention.

[0017] Figure 2 This is a block diagram illustrating a structural example of the signal conversion unit according to the first embodiment of the present invention.

[0018] Figure 3 This is a block diagram illustrating another structural example of the signal conversion unit according to the first embodiment of the present invention.

[0019] Figure 4 This is a diagram showing an example of the waveform obtained by frequency analysis of the phase current of a mechanical device (motor).

[0020] Figure 5 This is a flowchart illustrating an example of the processing procedure of the computing management unit according to the first embodiment of the present invention.

[0021] Figure 6 This is a diagram showing an example of the structure of a speed change device.

[0022] Figure 7 This is a block diagram illustrating a structural example of the diagnostic frequency candidate extraction unit according to the first embodiment of the present invention.

[0023] Figure 8 This is a block diagram illustrating a structural example of a transmission device monitoring system according to a second embodiment of the present invention.

[0024] Figure 9 This is a block diagram illustrating a structural example of the signal conversion unit according to the second embodiment of the present invention.

[0025] Figure 10 This is a block diagram illustrating a structural example of a transmission device monitoring system according to a third embodiment of the present invention.

[0026] Figure 11 This is a block diagram illustrating a structural example of the signal conversion unit according to the third embodiment of the present invention.

[0027] Figure 12 This is a block diagram illustrating a structural example of the diagnostic frequency candidate extraction unit according to the third embodiment of the present invention.

[0028] Figure 13 This is a block diagram illustrating a structural example of a transmission device monitoring system according to a fourth embodiment of the present invention.

[0029] Figure 14 This is a diagram showing an example of the spectrum of estimated torque current values ​​including the first diagnostic frequency candidate group and the second diagnostic frequency candidate group.

[0030] Symbol Explanation

[0031] 1…Drive power supply, 2…U-phase current sensor, 3…V-phase current sensor, 4…Motor, 5…Speed ​​changer, 6…Load device, 7, 807, 1307…Mechanical device, 8, 808, 1008, 1308…Diagnostic frequency estimation unit, 9, 9A, 809, 1009…Signal conversion unit, 10…Computational management unit, 11, 1011…Diagnostic frequency candidate extraction unit, 12…Diagnostic frequency selection unit, 13…Delay unit, 14…Division unit, 15…Abnormal diagnosis unit, 100, 100A, 100B, 100C…Speed ​​changer monitoring system. Detailed Implementation

[0032] Hereinafter, examples of embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In this specification and the drawings, constituent elements having substantially the same function or structure are labeled with the same reference numerals and repeated descriptions are omitted.

[0033] <First Implementation Method>

[0034] First, the transmission device monitoring system of the first embodiment of the present invention will be described.

[0035] In a first embodiment of the present invention, a transmission device monitoring system is described. The transmission device monitoring system estimates the vibration frequency (diagnostic frequency) required for diagnosing rotating components based on information such as the two-phase motor current, the total gear ratio of the mechanical device, the number of gear stages, and the number of motor poles, and diagnoses abnormalities of the mechanical device (especially the transmission device).

[0036] [Structure of the transmission monitoring system]

[0037] Figure 1 This is a block diagram illustrating a structural example of a transmission device monitoring system according to the first embodiment of the present invention.

[0038] exist Figure 1 In the transmission monitoring system 100 that monitors the status of the mechanical device 7, there is a diagnostic frequency estimation unit 8 and an anomaly diagnosis unit 15. The diagnostic frequency estimation unit 8 calculates the total gear ratio inside the mechanical device 7 and the current information related to the motor 4 (three-phase AC motor). Figure 1 The diagnostic frequency is estimated by taking the motor current (phase current), the number of speed stages, and the number of motor poles as inputs. The abnormality diagnosis unit 15 uses the diagnostic frequency calculated by the diagnostic frequency estimation unit 8 as input to calculate the degree of abnormality of the mechanical device 7 and monitor the state of the mechanical device 7. The number of speed stages indicates the number of speed changes performed to achieve the total speed ratio. (This will be discussed later.) Figure 6 In the example of the transmission device 5 shown, the number of transmission levels is 3.

[0039] In this specification, diagnostic frequency refers to the speed (frequency) of each rotating shaft before and after the gear shift in the transmission device 5. Figure 6 The speed change device 5 shown corresponds to the speed (frequency) of the four rotating shafts 51 to 54. The following is a detailed description of each of the aforementioned devices and processing units.

[0040] [Mechanical Device]

[0041] First, let’s explain the mechanical device 7.

[0042] Mechanical device 7 schematically represents the object being diagnosed by the transmission monitoring system 100. Examples of mechanical devices 7 include industrial machines such as machine tools, fans / pumps, and winches, automobiles, construction machinery, railway vehicles, or household electrical appliances. Mechanical device 7 consists of a motor 4, a transmission device 5 connected to the end of the motor 4, and a load device 6 from which power is transmitted from the transmission device 5. The motor 4 is driven by an AC voltage from a drive power source 1, such as a commercial power supply or an inverter. Here, the transmission device 5 is a device that changes the rotational speed of rotating shafts (rotating components) such as reducers and speed increasers through gears, matching all the transmission mechanisms (gear ratios) included in mechanical device 7.

[0043] [Diagnostic Frequency Estimation Section]

[0044] Next, the diagnostic frequency estimation section 8 will be explained.

[0045] The diagnostic frequency estimation unit 8 is a processing block that extracts the frequencies (diagnostic frequencies) of the rotating shafts before and after multiple speed changes based on input information such as motor current values. Furthermore, in this diagnostic frequency estimation unit 8, for... Figure 6 In addition to the frequencies of the input shaft (rotation shaft 51) and output shaft (rotation shaft 54) of the speed change device 5 shown, the frequency of the rotation shaft after the speed change is performed step by step from the input shaft is estimated (diagnostic frequency).

[0046] First, the signal conversion unit 9 takes the two-phase motor current (phase current) and the number of motor poles detected by the current sensors 2 and 3, which are current detection units, as input as information related to the current of the motor 4, and outputs the torque current estimation value and the motor speed estimation value. For example, the diagnostic frequency estimation unit 8 can be implemented by a microcomputer or an FPGA (Field Programmable Gate Array), and actually reads the motor current (in the AC converter) via an AD converter. Figure 1 (The AD converter is omitted).

[0047] Torque current is the current flowing based on the torque generated in motor 4. It has minimal frequency variation and can be treated as a DC current. The current obtained is assumed to be a two-phase current, but it can also be a three-phase current. Furthermore, in the case of a two-phase current, the two phases obtained can be any combination of U-phase, V-phase, and W-phase. In this embodiment, the current is obtained from the U-phase and V-phase.

[0048] The number of motor poles indicates the number of magnet poles used in the rotating rotor of motor 4. Regarding the number of motor poles, for example, the user can manually input the information recorded on the nameplate of motor 4 into the transmission monitoring system 100. The estimated torque current value calculated by the signal conversion unit 9 is input to the diagnostic frequency candidate extraction unit 11. Additionally, the estimated motor speed value is input to the calculation management unit 10, and simultaneously input to the division unit 14 using the total gear ratio and the fault diagnosis unit 15.

[0049] In this embodiment, a block diagram is provided assuming that all components of the rotating shaft with mechanical device 7 are being diagnosed. Therefore, the estimated motor speed is used for diagnosing components located on the input shaft of the transmission 5 (rotating shaft 51, which is the same as the motor shaft). Additionally, the output of the divider 14 is used for diagnosing components located on the output shaft (rotating shaft 54) of the transmission 5 after all gear changes have been completed. Furthermore, information on the total gear ratio can be obtained from the nameplate provided on the transmission 5, just like the number of motor poles.

[0050] Next, the calculation management unit 10, which has received the estimated motor speed value, also receives the number of gear shift stages of the transmission device 5 from the delay unit 13 and the diagnostic frequency (the frequency after shifting before stage 1) output by the diagnostic frequency selection unit 12 before step 1. The calculation step is managed by the calculation management unit 10. Furthermore, the information required to calculate the frequency after deceleration estimated by the diagnostic frequency candidate extraction unit 11, namely the input frequency W before shifting and the number of gear shift stages N indicating which gear shift stage from the output shaft is being calculated, is input to the diagnostic frequency candidate extraction unit 11.

[0051] Furthermore, the diagnostic frequency candidate extraction unit 11, which has been input with the total gear ratio, estimated torque current, estimated motor speed, input frequency W, and number of stages N, outputs a first diagnostic frequency candidate group and a second diagnostic frequency candidate group. Both the first and second diagnostic frequency candidate groups have one or more frequencies. In this embodiment, only two frequency candidate groups are specified, but the diagnostic frequency candidate extraction unit 11 can also extract three or more frequency candidate groups.

[0052] The diagnostic frequency candidate extraction unit 11 calculates the frequency of the rotating shaft after the shift of the current shift stage based on the speed of the motor 4 (e.g., an estimated motor speed), the shift ratio (total shift ratio) of the transmission 5, the current shift stage (number of stages N) of the transmission 5, and the input frequency W of the current shift stage (number of stages N). Based on the frequency of the rotating shaft after the shift, it extracts one or more frequencies from the spectrum obtained based on the current information (e.g., an estimated torque current) related to the motor 4 (see below). Figure 14This serves as the second diagnostic frequency candidate group. Furthermore, the diagnostic frequency candidate extraction unit 11 is configured to extract one or more frequencies from the spectrum obtained based on current information (e.g., torque current estimation value) related to the motor 4, according to the meshing frequency of the gears constituting the current transmission stage (see below). Figure 14 () as the first diagnostic frequency candidate group.

[0053] Therefore, based on the current information related to the motor 4, which is a composite superposition of mechanical and electrical vibrations, it is possible to accurately and automatically extract the abnormal vibration frequency components of rotating parts such as rotating shafts and gears of the transmission device 5 for diagnosis.

[0054] Furthermore, the signal conversion unit 9 is configured to estimate the speed of the motor 4 by dividing the frequency obtained by parsing the current information (e.g., an estimated motor speed) related to the motor 4 by the number of poles of the motor 4. In this way, the estimated motor speed can be obtained based on the current information related to the motor 4.

[0055] Finally, the diagnostic frequency selection unit 12 compares the first and second diagnostic frequency candidate groups described above, and selects the frequency component that exists in both diagnostic frequency candidate groups as the diagnostic frequency output. The frequency component that exists in both diagnostic frequency candidate groups is a frequency that satisfies a specific relationship among the frequencies obtained from the two diagnostic frequency candidate groups.

[0056] In this way, the diagnostic frequency selection unit 12 can accurately select the diagnostic frequency by selecting a frequency that satisfies a specific relationship from the frequencies obtained from the first diagnostic frequency candidate group and the second diagnostic frequency candidate group.

[0057] Here, the diagnostic frequency selection unit 12 can estimate the diagnostic frequency according to the rotational axes 51 to 54 (target axes) that are the objects of diagnosis for the transmission device 5, and save or output the diagnostic frequency to a memory (not shown). Hereinafter, each processing block of the signal conversion unit 9, the calculation management unit 10, the diagnostic frequency candidate extraction unit 11, and the diagnostic frequency selection unit 12 will be described in detail.

[0058] [Signal Conversion Section]

[0059] First, use Figure 2 The details of the signal conversion unit 9 will be explained.

[0060] Figure 2 This is a block diagram illustrating a structural example of the signal conversion unit 9 in the first embodiment.

[0061] The signal conversion unit 9 includes: a W-phase current generation unit 201, a three-phase to two-phase conversion unit 202, a phase calculation unit 203, a coordinate conversion unit 207, and a division unit 208.

[0062] Signal conversion unit 9 is a processing block that converts the motor current, which is a two-phase AC signal, into estimated torque current and estimated motor speed, which are DC quantities. Here, DC quantity refers to a signal that is constant if there is no load change. The estimated torque current and estimated motor speed, which will be explained later, can be processed as DC quantities because the fundamental frequency (power supply frequency) of the AC motor current (phase current) has been removed. The power supply frequency is, for example, the frequency of the drive power supply 1, and can be set to the frequency of a commercial power supply (50Hz, 60Hz).

[0063] This makes it easier to extract mechanical load variations such as vibration when converting motor current to DC. Additionally, it has the advantage of being able to extract vibration frequency components at the same frequency as those processed by a vibration sensor. When analyzing the spectrum of a signal, a constant rotational speed (frequency), i.e., DC, is preferred.

[0064] (First processing example of the signal conversion unit)

[0065] First, as the first processing method of the signal conversion unit 9, it is indicated that a current phase conversion processing method is used. First, the U-phase current Iu and V-phase current Iv obtained by the current sensors 2 and 3 are input to the W-phase current generation unit 201. This is a process to obtain three-phase current when the measured current is two-phase, and is not needed when current is obtained in all three phases. In the W-phase current generation unit 201, the processing shown in the following formula (1) is performed to calculate the W-phase current Iw.

[0066] [Mathematical Expression 1]

[0067] Iw=-(Iu+Iv)…(1)

[0068] Next, three-phase current is input from the W-phase current generation unit 201 to the three-phase two-phase conversion unit 202, and the processing shown in the following formulas (2) and (3) is performed in the three-phase two-phase conversion unit 202. As a result, Iα and Iβ are obtained as orthogonal two-axis current components based on the α-axis and β-axis.

[0069] [Mathematical Expression 2]

[0070] Iα=(2 / 3){Iu-Iv / 2-Iw / 2}…(2)

[0071] [Mathematical Expression 3]

[0072] Iβ=(1 / √3){Iv-Iw}…(3)

[0073] Then, the phase calculation unit 203 calculates the phase required for coordinate transformation (conversion to DC quantity) of the orthogonal two-axis current components based on the α-axis and β-axis. The phase calculation unit 203 consists of an instantaneous phase calculation unit 204, a PLL (Phase Locked Loop) unit 205, and an integration unit 206. In the instantaneous phase calculation unit 204, the instantaneous phase θi is calculated by performing the process shown in the following formula (4). * .

[0074] [Mathematical Expression 4]

[0075] θi * =tan -1 (Iβ / Iα)…(4)

[0076] Instantaneous phase θi * Through the feedback loop consisting of PLL unit 205 and integrator unit 206, the coordinate transformation phase θi is finally generated in integrator unit 206. That is, the instantaneous phase θi is calculated in addition unit 209. * The value of the coordinate transformation phase θi, after being subtracted from the coordinate transformation phase θi output from the integrator 206, is input to the PLL unit 205 for phase synchronization processing. Then, the output of the PLL unit 205 is input to the integrator 206, where they are sequentially added. The value of this coordinate transformation phase θi is an estimated value for the rotor position of the motor 4. The PLL unit 205 for phase synchronization processing can also be considered a phase storage unit that stores phase information.

[0077] Furthermore, during this process, the estimated electrical velocity (i.e., power supply frequency) Wi is obtained through the PLL unit 205. This feedback loop has a noise removal function; therefore, if the instantaneous phase θi is not a concern... * In the presence of noise (electrical or mechanical noise), it is also possible to avoid changing the instantaneous phase θi. * Through the feedback loop described above. For example, at the instantaneous phase θi * If the noise level is lower than the specified value, no feedback processing is performed. That is, the adder 209, PLL 205, and integrator 206 are not required. The structure of this phase calculation unit 203 is also described in International Publication 2019 / 049188.

[0078] Furthermore, the coordinate transformation unit 207 inputs the orthogonal two-axis current components Iα and Iβ based on the α-axis and β-axis obtained by the three-phase two-phase transformation unit 202, and the coordinate transformation phase θi obtained by the phase calculation unit 203, and performs coordinate transformation in the coordinate transformation unit 207. As shown in the following formula (5), the coordinate transformation is the process of obtaining the DC current Ia related to the motor 4. The DC current Ia is the effective current component. The ineffective current component Iz is not used here.

[0079] [Mathematical Expression 5]

[0080] Ia=Iα·cos(θi)+Iβ·sin(θi)…(5)

[0081] The DC current Ia calculated in this way, and the estimated electrical speed Wi output from the phase calculation unit 203, are both DC currents. Here, in the division unit 208, the estimated electrical speed Wi is divided by the number of motor poles to obtain an estimated motor speed (rotation frequency of the motor shaft). Furthermore, since the DC current Ia is similar to the time variation of the torque current used in motor control, it is referred to as "estimated torque current value" in this specification. This calculation method assumes an installation model that can be applied under any circumstances, regardless of whether the motor 4 operates at a constant or variable speed.

[0082] (Second processing example of the signal conversion unit)

[0083] Next, use Figure 3 The second processing method of the signal conversion unit 9 will be explained.

[0084] Figure 3 This is a block diagram showing another structural example of the signal conversion unit 9 in the first embodiment.

[0085] Figure 3 Before the signal conversion unit 9A shown calculates Iα and Iβ through the W-phase current generation unit 201 and the three-phase two-phase conversion unit 202, it connects with... Figure 2 The calculation method of the signal conversion unit 9 shown is the same. In the calculation of the torque current estimate, after the three-phase two-phase conversion unit 202, the signal conversion unit 9A performs the following formula (6) in the processing block 312 using Iα and Iβ. That is, the root mean square of Iα and Iβ is calculated.

[0086] [Mathematical Expression 6]

[0087]

[0088] On the other hand, in the calculation of the estimated motor speed, the frequency analysis unit 313 converts the signal of one phase (the signal on the time axis) of the U-phase current Iu and the V-phase current Iv into... Figure 4 The signal has a frequency axis as shown. Therefore, the peak frequency extraction unit 314 extracts the frequency with the peak amplitude from the U-phase current Iu or the V-phase current Iv.

[0089] Figure 4 This is a diagram illustrating an example of the waveform obtained by frequency analysis of the phase current of mechanical device 7 (motor 4). Figure 4 In the diagram, the horizontal axis represents frequency, and the vertical axis represents amplitude.

[0090] The peak frequency of the phase current is the frequency of the power supply driving the motor 4. Therefore, by dividing this peak frequency by the number of motor poles using the division unit 315, an estimated motor speed can be calculated. Furthermore, this method is preferably used when the motor 4 is operating at a constant speed. This is because, as described above, the FFT (High-Speed ​​Fourier Transform) used in the frequency analysis unit 313 provides improved accuracy when the rotational speed is constant.

[0091] The structure and operation of the signal conversion unit 9, which converts AC current information related to motor 4 into DC current, can, for example, utilize known technologies as described in International Publication No. 2019 / 049188.

[0092] [Computer Management Department]

[0093] Next, use Figure 5 The Computing Management Department 10 will be explained.

[0094] The calculation management unit 10 is a block that controls the processing of the diagnostic frequency estimation unit 8, and manages the calculation steps and the information required for the calculation.

[0095] Figure 5 This is a flowchart illustrating a process example of the calculation management unit 10. When the calculation is first started in the calculation management unit 10 (S1), information about the number of gear shifts of the transmission device 5 is input into the variable N (S2). At this time, the calculation management unit 10 sets the flag S, which indicates that the calculation is an initial estimate, to 1.

[0096] Here, refer to Figure 6 The transmission device 5 will be described.

[0097] Figure 6 This is a diagram showing an example of the structure of the transmission device 5.

[0098] Here, as an example, when considering the presumption Figure 6 When the rotational shafts 51 to 54 of the transmission device 5 are at certain frequencies, the number of transmission stages N is 3 (3-stage transmission). The transmission stages are counted from the output shaft side. In each transmission stage, the front gear and the rear gear with different numbers of teeth mesh and rotate, thereby changing the rotational frequency of the rotational shafts 52 to 54.

[0099] Next, the calculation management department 10 checks whether the level N is 1 (S3). Here, since N = 3, it is determined to be no in step S3, and proceeds to step S4.

[0100] Next, the calculation management unit 10 checks whether it is the first calculation using the flag S (S4). Currently, the flag S is 1, so it is determined to be yes in step S4. Next, in step S8, the calculation management unit 10 sets the flag S to 0 and sets the input frequency W before speed change input to the diagnostic frequency candidate extraction unit 11 to the motor speed estimation value estimated by the signal conversion unit 9 (S8).

[0101] Here, in use Figure 6 In this explanation, the input frequency W is used to calculate the frequency of the rotating shaft 52 (the second shaft from the left) after the first speed change. The input frequency W used at this time is the frequency of the rotating shaft 51 before the speed change, which is the estimated motor speed value. Therefore, in step S8, the estimated motor speed value is set as the input frequency W.

[0102] Then, after the processing in step S8, the management unit 10 calculates the input frequency W and the number of stages N (S6). Next, in step S7, the management unit 10 updates the number of stages N (N = N-1), and the diagnostic frequency is determined by the diagnostic frequency candidate extraction unit 11. Figure 6 Regarding the estimation of the estimated value 1), after processing in step S7, return to step S3.

[0103] In the second cycle ( Figure 6 In the estimation of the frequency of the third rotation axis 53 from the left, N=2 and S=0. Therefore, after the negative checks in steps S3 and S4, the process proceeds to step S5. Here, the calculation management unit 10 will calculate the diagnostic frequency (currently the estimated rotation frequency of the third axis from the left) calculated before step 1. Figure 6 The estimated value 1 (the diagnostic frequency before step 1) is set as the input frequency W.

[0104] Then, the calculation management unit 10 proceeds to steps S6 and S7, updates the level N (N = N-1), and performs diagnostic frequency extraction by the diagnostic frequency candidate extraction unit 11. Figure 6 The estimated value 2) is estimated. After processing in step S7, return to step S3.

[0105] Then, in the third loop, N=1, therefore, the calculation management unit 10 determines in step S3 that it is yes, and ends the estimation of the diagnostic frequency by the diagnostic frequency candidate extraction unit 11 (S9). After step S9, this flowchart ends (S10). In addition, the rotational frequencies of the input shaft (rotation shaft 51) and output shaft (rotation shaft 54) of the transmission device 5 can be calculated using the estimated motor speed and the total gear ratio (total reduction ratio), therefore, the diagnostic frequency candidate extraction unit 11 does not perform estimation calculation.

[0106] [Diagnostic Frequency Candidate Extraction Department]

[0107] Next, use Figure 7 The diagnostic frequency candidate extraction unit 11 will be explained.

[0108] Figure 7 This is a block diagram illustrating a structural example of the diagnostic frequency candidate extraction unit 11 in the first embodiment.

[0109] The diagnostic frequency candidate extraction unit 11 uses two different methods to extract the diagnostic frequency candidate group. The details of the different methods will be described later, but the key point is that it uses the following principle: the rotating shafts 51 to 54 always rotate with slight misalignment and eccentricity, so in the gear mechanism, the effect is manifested in both the sideband waves of the rotation frequency and the meshing frequency.

[0110] like Figure 7 As shown, the diagnostic frequency candidate extraction unit 11 is composed of a frequency analysis unit 701, a total gear ratio recalculation unit 702, a gear ratio division unit 703, a multiplication unit 704, a frequency peak extraction unit 705, a multiplication unit 706, and a sideband wave peak extraction unit 707.

[0111] First, the estimated torque current value input to the diagnostic frequency candidate extraction unit 11 is input to the frequency analysis unit 701, where information from the time axis is converted to information from the frequency axis using methods such as FFT (High-Speed ​​Fourier Transform). The frequency axis information of the estimated torque current value, i.e., the spectrum information, is input from the frequency analysis unit 701 to the frequency peak extraction unit 705.

[0112] Next, the input frequency W before the gear shift, the estimated motor speed, and the information of the total gear ratio are input to the total gear ratio recalculation unit 702. In this total gear ratio recalculation unit 702, the total gear ratio from the gear stage from which the current diagnostic frequency is to be estimated to the final gear stage is recalculated.

[0113] by Figure 6 For example, if the rotational frequency of the third rotational axis 53 from the left is currently estimated, the product of the gear ratio of the second stage and the gear ratio of the third stage is the new total gear ratio. On the other hand, if the rotational frequency of the second rotational axis 52 from the left is estimated, the total gear ratio itself input to the diagnostic frequency candidate extraction unit 11 can be used. Therefore, the recalculation of the total gear ratio is performed as shown in the following formula (7).

[0114] [Mathematical Expression 7]

[0115] Then calculate the total gear ratio = total gear ratio / (W / estimated motor speed)...(7)

[0116] The total gear ratio, calculated as described above, along with the number of gears N indicating which gear stage the calculation is performed for from the output shaft, is input from the total gear ratio recalculation unit 702 to the gear ratio division unit 703. Furthermore, based on the recalculated total gear ratio, the gear ratio R of the current gear stage is estimated. That is, gear ratio division refers to a portion of the total gear ratio of the transmission device 5, representing the division of the total gear ratio component (gear ratio R). As a calculation method, for example, a table can be maintained for each gear ratio R based on the relationship between the recalculated total gear ratio and the number of gears N, and this table can be used. For example, this table can be stored in a non-volatile memory (not shown) included in the gear ratio division unit 703 or the diagnostic frequency candidate extraction unit 11.

[0117] Furthermore, the gear ratio R calculated by the gear ratio division unit 703 is multiplied by the input frequency W in the multiplication unit 704, and input together with the analysis result of the frequency analysis unit 701 to the frequency peak extraction unit 705. The output of the multiplication unit 704 is equivalent to the rotation frequency of the rotating shaft after the gear shift, which is set as the gear shift stage of the current object. In addition, the value of the gear ratio R output from the gear ratio division unit 703 may not be 1, and the gear ratio R may be a value with a certain range.

[0118] In the frequency peak extraction unit 705, the value calculated by the multiplication unit 704 is searched from the spectrum calculated by the frequency analysis unit 701. As a method, for example, one or more frequency peaks existing within ±10% of the output value of the multiplication unit 704 can be extracted. Furthermore, if the gear ratio R is calculated within a certain range in the gear ratio division unit 703, only one or more frequency peaks within that range need to be extracted, and the extraction result is output as a second diagnostic frequency candidate group.

[0119] On the other hand, the input frequency W is also input to the multiplication unit 706 and multiplied by the estimated number of teeth of the gear on the input side of the transmission stage being calculated. This is equivalent to calculating the frequency of the meshing vibration (an example of mechanical vibration) generated from the gear. At this time, the estimated number of teeth is calculated in advance based on the design values ​​of multiple transmission devices, etc., and stored in a non-volatile memory (not shown) provided in the diagnostic frequency candidate extraction unit 11, etc. In addition, the estimated number of teeth may not be one, but may have a certain range.

[0120] The output from the multiplication unit 706 and the output from the frequency analysis unit 701 (the spectrum of the estimated torque current value) are input to the sideband peak extraction unit 707. The sideband peak extraction unit 707 first searches for the meshing frequency from the spectrum of the estimated torque current value. As a search method, it searches for the maximum peak value within, for example, ±10% of the output value of the multiplication unit 706. At this time, the sideband peak extraction unit 707 does not search for higher harmonics of electrical noise, but can perform a search using multiple conditions as AND conditions. If the output value of the multiplication unit 706 has a certain range, the search can also be performed within that range using the aforementioned multiple conditions. Furthermore, the sideband peak extraction unit 707 extracts the peak frequency of the sideband wave existing at the determined meshing frequency (e.g., within ±10% of the meshing frequency) as the output of a first diagnostic frequency candidate group. In addition, the number of extracted frequencies can be one or more. In addition, the conditions for the frequency extracted from the sideband wave of the meshing frequency are set in advance through experiments or the like in a non-volatile memory (not shown) provided in the sideband wave peak extraction unit 707 or the diagnostic frequency candidate extraction unit 11.

[0121] [Diagnostic Frequency Selection Unit]

[0122] Next, use Figure 7 The diagnostic frequency selection unit 12 will be explained.

[0123] Diagnostic frequency selection unit 12 ( Figure 1 The frequency (second diagnostic frequency candidate) included in the second diagnostic frequency candidate group output from the diagnostic frequency candidate extraction unit 11 is compared with the frequency obtained by subtracting the meshing frequency from the first diagnostic frequency candidate group and taking the absolute value. The frequency at which a specific relationship exists between the two diagnostic frequency candidate groups is output as the diagnostic frequency. Among the two frequencies at which this specific relationship exists, the relationship "frequency difference Δf = meshing frequency - (second diagnostic frequency candidate) × 2" or "frequency difference Δf = meshing frequency" holds true.

[0124] Thus, any of the following relationships hold true regarding the frequency difference Δf (at a specific frequency).

[0125] • Frequency difference Δf = Meshing frequency of the gears in transmission device 5 - (Frequency extracted from the second diagnostic frequency candidate group × 2)

[0126] • Frequency difference Δf = meshing frequency of the meshing gears

[0127] Therefore, the diagnostic frequency selection unit 12 can extract multiple diagnostic frequency candidate groups from frequency regions with a frequency difference Δf (a specific frequency) or more, and estimate a frequency that satisfies a specific relationship from the frequencies obtained from the multiple diagnostic frequency candidate groups as the diagnostic frequency.

[0128] [Spectrum including the first and second diagnostic frequency candidate groups]

[0129] Figure 14 This is a diagram showing an example of the spectrum of estimated torque current values ​​including the first diagnostic frequency candidate group and the second diagnostic frequency candidate group. Figure 14 The example shown is the spectrum of the estimated torque current when specific values ​​are applied to mechanical device 7.

[0130] exist Figure 14 The frequency spectrum of the first stage of the transmission is shown only when the total gear ratio in a two-stage transmission is 1 / 4 and the gear ratio of each stage is 1 / 2. That is, the transmission device has an input shaft, an output shaft, and a rotating shaft disposed between them. Furthermore, it is assumed that the input shaft gear has 30 teeth, the gear meshing with the input shaft gear has 60 teeth, the input shaft speed is 10Hz, the rotated speed of the rotating shaft meshing with the input shaft after the speed change is 5Hz, and the meshing frequency of the first stage of the transmission is 300Hz.

[0131] When this embodiment is applied to the mechanical device 7 under such conditions, the diagnostic frequency selection unit 12 selects 5Hz from the second diagnostic frequency candidate group and selects 295Hz or 305Hz from the first diagnostic frequency candidate group. That is, it can be seen that the difference (specific frequency) between the frequencies extracted from each of the first and second diagnostic frequency candidate groups is the relationship described above. Furthermore, the diagnostic frequency selection unit 12 selects 5Hz extracted from the second diagnostic frequency candidate group as the diagnostic frequency of the rotating shaft meshing with the input shaft and outputs it to the abnormality diagnosis unit 15.

[0132] In this way, the diagnostic frequency selection unit 12 selects a frequency that satisfies the specific relationship described above from the frequencies included in the second diagnostic frequency candidate group as the diagnostic frequency. As a result, the diagnostic frequency selection unit 12 can accurately and automatically select a diagnostic frequency from the second diagnostic frequency candidate group extracted by the diagnostic frequency candidate extraction unit 11 by utilizing two completely different phenomena in geared mechanisms, namely, the mechanical effects of which manifest as sideband waves at the rotational frequency and the meshing frequency.

[0133] Furthermore, as shown in the specific example, in this embodiment, when there are two candidate groups for multiple diagnostic frequencies, the first candidate group for diagnostic frequencies consists of one or more frequencies extracted from the sideband wave of the meshing frequency (e.g., 300Hz) of the gears meshing in the transmission device 5. The second candidate group for diagnostic frequencies consists of one or more frequencies (e.g., 5Hz) extracted from sources other than the sideband wave of the meshing frequency (e.g., 300Hz) of the gears meshing in the transmission device 5.

[0134] [Abnormal Diagnosis Department]

[0135] Finally, the abnormality diagnosis section 15 will be explained.

[0136] In the anomaly diagnosis unit 15, anomaly diagnosis (e.g., anomaly degree calculation) of the transmission device 5 is performed using the diagnostic frequency estimated by the diagnostic frequency estimation unit 8. Anomaly diagnosis may involve inputting the amplitude component of the diagnostic frequency into a pre-prepared model to calculate an evaluation value (continuous or discrete) representing the abnormal state, or outputting a result obtained by directly comparing the amplitude component with a threshold (e.g., anomaly degree). When using a model, models that have learned normal states and models that have learned both abnormal and normal states may be considered, and models such as regression models, classification models, cluster models, and neural networks may be used to construct the model.

[0137] Furthermore, the amplitude component of the diagnostic frequency mentioned above can also be the amplitude component of the frequency obtained by multiplying the diagnostic frequency by a coefficient. The coefficient can be, for example, a value derived from the shape of the bearing on the rotating shaft, the number of teeth on a gear, etc., or it can be an integer or fractional value multiplied by the diagnostic frequency. Moreover, the anomaly diagnosis unit 15 can use multiple input values ​​for diagnostic frequencies, or it can use a single value. Additionally, the models for calculating the degree of anomaly can, for example, exist in multiple ways depending on the diagnostic location of the object being diagnosed (in this case, the transmission device 5).

[0138] According to the transmission monitoring system 100 of the first embodiment configured as described above, the abnormal vibration frequency component for diagnosing the rotating component (transmission device 5) can be accurately and automatically estimated based solely on information such as motor current, total gear ratio, number of gear stages, and number of motor poles, using only the motor current superimposed with mechanical and electrical noise. Furthermore, by using its diagnostic frequency component, the transmission monitoring system of this embodiment can be expected to achieve improved diagnostic accuracy and reduce the time required to construct the transmission monitoring system.

[0139] <Second Implementation Method>

[0140] In the second embodiment of the present invention, a transmission device monitoring system is described. The transmission device monitoring system estimates the vibration frequency (diagnostic frequency) required for the diagnosis of the rotating component based on information such as the motor current of one phase, the total speed ratio and number of speed stages of the mechanical device 7, and the number of poles of the motor 4, and calculates the degree of abnormality.

[0141] [Structure of the transmission monitoring system]

[0142] Figure 8 This is a block diagram illustrating a structural example of a transmission device monitoring system according to a second embodiment of the present invention.

[0143] In the second embodiment, descriptions of the same structure and processes as in the first embodiment are omitted. The transmission monitoring system 100A of the second embodiment is similar to the transmission monitoring system 100 of the first embodiment. Figure 1 The difference lies in that, as current information related to motor 4, only the motor current of one phase is used. Therefore, the transmission monitoring system 100A has a signal conversion unit 809 instead of the signal conversion unit 9. In this embodiment, the U-phase current Iu is obtained by the current sensor 2. Furthermore, the phase of the obtained current can be any one of the U-phase, V-phase, and W-phase. The obtained motor current is input to the signal conversion unit 809.

[0144] [Signal Conversion Section]

[0145] Next, use Figure 9 The details of the signal conversion unit 809 will be explained.

[0146] Figure 9 This is a block diagram illustrating a structural example of the signal conversion unit 809 in the second embodiment.

[0147] As in the first embodiment, the signal conversion unit 809 performs the processing of calculating the estimated torque current value and the estimated motor speed value. The input U-phase current Iu is input to the envelope detector 901 to calculate the estimated torque current value.

[0148] Methods for processing the envelope include the Hilbert transform. The value of the phase current after envelope processing, by removing the alternating positive and negative AC components, becomes a DC current, which approximates the torque current variation. Therefore, the value of the phase current after envelope processing can be used as an estimated torque current value. On the other hand, the calculation of the estimated motor speed... Figure 3 The method of the signal conversion unit 9 shown is the same, therefore, the description is omitted.

[0149] According to the second embodiment described above, the transmission monitoring system 100B can reduce the number of current sensors compared to the first embodiment, thus reducing the cost of constructing the transmission monitoring system.

[0150] <Third Implementation Method>

[0151] In a third embodiment of the present invention, another transmission device monitoring system will be described. This system calculates the degree of abnormality by estimating the vibration frequency (diagnostic frequency) required for diagnosing the rotating component based on information such as the motor current of one phase, the total gear ratio and number of gear stages of the mechanical device 7, and the number of poles of the motor 4. That is, the third embodiment can also be considered a variation of the second embodiment.

[0152] [Structure of the transmission monitoring system]

[0153] Figure 10 This is a block diagram illustrating a structural example of a transmission device monitoring system according to a third embodiment of the present invention.

[0154] In the third embodiment, the parts that perform the same structure and processing as in the first and second embodiments are omitted from repeated description. The transmission monitoring system 100B of the third embodiment differs from the transmission monitoring systems 100 and 100A of the first and second embodiments in two aspects. The first aspect is that the phase current itself is output from the signal conversion unit 1009 instead of the estimated value of the torque current, and the second aspect is that the processing method of the diagnostic frequency candidate extraction unit 1011 is different.

[0155] [Signal Conversion Section]

[0156] Next, use Figure 11 The details of the signal conversion unit 1009 are explained below.

[0157] Figure 11 This is a block diagram illustrating a structural example of the signal conversion unit 1009 in the third embodiment.

[0158] The signal conversion unit 1009 does not perform the process of converting motor current into DC quantity as in the first and second embodiments, but directly outputs phase current. Figure 11 The document describes a structure in which the U-phase current Iu obtained by the current sensor 2 is directly output to the diagnostic frequency candidate extraction unit 1011.

[0159] [Diagnostic Frequency Candidate Extraction Department]

[0160] Next, use Figure 12 The details of the diagnostic frequency candidate extraction unit 1011 are explained.

[0161] Figure 12 This is a block diagram illustrating a structural example of the diagnostic frequency candidate extraction unit 1011 in the third embodiment.

[0162] In the diagnostic frequency candidate extraction unit 1011 of the input phase current, such as Figure 12 As shown, except for the frequency peak extraction unit (for phase current) 1205 and the sideband peak extraction unit (for phase current) 1207, the same processing as in the first embodiment is performed.

[0163] In the frequency peak extraction unit 1205, the target of the search is the spectrum of the phase current. Therefore, the search is performed by adding the power supply frequency to the value output from the multiplication unit 704. As described above, the output of the multiplication unit 704 corresponds to the rotation frequency of the rotating shaft after the speed change of the speed change stage, which is set as the target. Furthermore, in the sideband peak extraction unit 1207, the search is also performed by adding the power supply frequency to the value output from the multiplication unit 706. That is, as described in the first embodiment... Figure 14 The information on the frequency axis is also expressed as an offset from the power supply frequency.

[0164] For example, in the first embodiment, the frequency peak extraction unit 705 ( Figure 7 Choose from Figure 14 The "5Hz" extracted from the second diagnostic frequency candidate group shown is taken as the vibration frequency. Assuming the power supply frequency is set to 50Hz, adding the power supply frequency of 50Hz to this 5Hz results in "55Hz". Furthermore, in Figure 14 In the example, the meshing frequency "300Hz" is displayed as an example of the first vibration frequency candidate group. With a meshing frequency of 300Hz, adding a power supply frequency of 50Hz results in "350Hz".

[0165] The transmission monitoring system 100B according to this third embodiment, compared to the first embodiment, can reduce the number of current sensors, thus reducing the cost of constructing the transmission monitoring system. Furthermore, compared to the second embodiment, this embodiment simplifies signal conversion processing. Therefore, the processing load of the transmission monitoring system can be reduced.

[0166] According to the transmission device monitoring systems 100, 100A, and 100B of the first to third embodiments described above, the signal conversion units 9, 809, and 1009 can obtain current information (motor current) related to the motor 4 from a current sensor provided in at least one phase of the motor 4 and perform diagnostics.

[0167] Furthermore, as shown in the specific example, in this embodiment, when there are two candidate groups for multiple diagnostic frequencies, the first candidate group for diagnostic frequencies consists of one or more frequencies extracted from the sideband wave of the frequency obtained by adding the power supply frequency of the drive power supply 1 of the motor 4 to the meshing frequency of the gear meshing with the gear of the transmission 5 (e.g., 300Hz). The second candidate group for diagnostic frequencies consists of one or more frequencies (e.g., 55Hz) extracted from the sideband wave of the frequency obtained by adding the power supply frequency of the drive power supply 1 of the motor 4 to the meshing frequency of the gear meshing with the transmission 5 (e.g., 300Hz) to the power supply frequency of the drive power supply 1 of the motor 4 (e.g., 50Hz).

[0168] <Fourth Implementation Method>

[0169] In the fourth embodiment of the present invention, a transmission device monitoring system is described, which estimates the vibration frequency (diagnostic frequency) required for the diagnosis of rotating components and calculates the degree of abnormality based on information such as torque current, total gear ratio and number of gears of the mechanical device, and motor speed.

[0170] [Structure of the transmission monitoring system]

[0171] Figure 13 This is a block diagram illustrating a structural example of a transmission device monitoring system according to a fourth embodiment of the present invention.

[0172] In the fourth embodiment, the parts that perform the same structure and processing as in the first to third embodiments are omitted from the description. The difference between the transmission monitoring system 100C of the fourth embodiment and the transmission monitoring systems 100 to 100B of the first to third embodiments is that, as current information related to the motor 4, information on torque current and motor speed, which has been converted to DC values, is obtained from the drive power supply 1301 (inverter). The drive power supply 1301 of the mechanical device 1307, in addition to outputting the aforementioned torque current and motor speed information to the diagnostic frequency candidate extraction unit 11, has the same characteristics as the drive power supply 1 (…). Figure 1 It has the same structure.

[0173] Therefore, in this embodiment, the signal conversion units 9, 809, and 1009 present in the transmission monitoring systems 100-100B of the first to third embodiments are not required. Torque current information is directly input from the drive power supply 1301 to the diagnostic frequency candidate extraction unit 11. Furthermore, motor speed information is directly input from the drive power supply 1301 to the diagnostic frequency candidate extraction unit 11, the calculation management unit 10, the division unit 14, and the anomaly diagnosis unit 15. Moreover, the contents of the other processing blocks are the same as those described in the first and second embodiments, therefore, descriptions are omitted.

[0174] According to the fourth embodiment described above, the transmission device monitoring system 100C reduces the number of current sensors and the processing load of the transmission device monitoring system compared to the first to third embodiments.

[0175] <Summary of the first to fourth implementation methods>

[0176] As described above, the transmission monitoring system of the first to fourth embodiments of the present invention is a transmission monitoring system for monitoring transmission devices driven by motors, and has a diagnostic frequency estimation unit and an abnormality diagnosis unit.

[0177] The aforementioned diagnostic frequency estimation unit is configured to use at least the current information related to the motor, the gear ratio of the transmission device, and the number of gears of the transmission device to extract multiple diagnostic frequency candidate groups from frequency regions that are more than a certain frequency (frequency difference Δf), and to estimate a frequency that satisfies a specific relationship from the frequencies obtained from the multiple diagnostic frequency candidate groups as the diagnostic frequency.

[0178] The above-mentioned abnormality diagnosis unit is configured to use at least one diagnosis frequency estimated by the above-mentioned diagnosis frequency estimation unit to diagnose abnormalities of the transmission device.

[0179] The transmission monitoring system according to the first to fourth embodiments described above can accurately and automatically estimate the abnormal vibration frequency component for diagnosing the rotating parts of the transmission based on the motor-related current information (motor current, torque current, etc.) that is a composite superposition of mechanical and electrical vibrations. Furthermore, by using its diagnostic frequency component, the transmission monitoring system of each embodiment can be expected to improve diagnostic accuracy and reduce the time required to construct the transmission monitoring system.

[0180] <Variation Example>

[0181] Furthermore, the present invention is not limited to the embodiments described above. As long as it does not depart from the spirit of the present invention as described in the technical solution for which patent protection is sought, various other application examples and modifications can be adopted.

[0182] For example, the above embodiments are detailed and specific descriptions of the structure of the monitoring system for ease of understanding of the present invention, and are not limited to having all the structural elements described. Furthermore, a portion of the structure of one embodiment can be replaced with structural elements of other embodiments. Additionally, structural elements of other embodiments can be added to the structure of one embodiment. Furthermore, for a portion of the structure of each embodiment, other structural elements can be added, replaced, or deleted.

[0183] Furthermore, in the above embodiments, the control lines and information lines represent the parts deemed necessary for explanation, and do not necessarily show all the control lines and information lines on the product. In fact, it can be considered that almost all the constituent elements are interconnected.

[0184] Furthermore, the various structures, functions, and processing units described in the various embodiments can be partially or entirely implemented in hardware, for example, through design in an integrated circuit. As hardware, processor devices in a broad sense, such as FPGAs (Field Programmable Gate Arrays) and ASICs (Application Specific Integrated Circuits), can also be used. Additionally, in the speed changer monitoring systems of the above embodiments, the processing performed by a certain processing unit can be implemented by a single piece of hardware, or it can be implemented through distributed processing based on multiple pieces of hardware.

[0185] Furthermore, the aforementioned components, functions, and processing units can also be implemented in software by having the computer's processor interpret and execute the programs that perform each function. The programs, tables, files, and other information that implement each function can be stored in recording devices such as memory, hard disks, SSDs (Solid State Drives), or recording media such as IC cards, SD cards, and optical discs.

Claims

1. A transmission device monitoring system for monitoring a motor-driven transmission device, characterized in that, have: The diagnostic frequency estimation unit uses at least current information related to the motor, the gear ratio of the transmission, and the number of stages of the transmission to estimate the diagnostic frequency; and The anomaly diagnosis unit uses at least one diagnosis frequency estimated by the diagnosis frequency estimation unit to diagnose anomalies in the transmission device. The diagnostic frequency estimation unit calculates the frequency of the post-shift rotating shaft in the current shift stage based on the speed of the motor, the shift ratio of the transmission, the current shift stage of the transmission, and the input frequency of the current shift stage. Based on the frequency of the post-shift rotating shaft, it extracts one or more frequencies from the spectrum obtained based on the current information related to the motor as a second diagnostic frequency candidate group. In addition, based on the meshing frequency of the gears constituting the current shift stage, it extracts one or more sideband frequencies of the meshing frequency from the spectrum obtained based on the current information related to the motor as a first diagnostic frequency candidate group. Based on the difference between the frequency of the sideband frequency of the one or more meshing frequencies extracted as the first diagnostic frequency candidate group and the meshing frequency, it selects the diagnostic frequency from one or more frequencies extracted as the second diagnostic frequency candidate group.

2. The transmission device monitoring system according to claim 1, characterized in that, Current information related to the motor is obtained from a current sensor located in at least one phase of the motor.

3. The transmission device monitoring system according to claim 1, characterized in that, The current information associated with the motor is the torque current that can be obtained from the drive power supply that drives the motor.

4. The transmission device monitoring system according to claim 2 or 3, characterized in that, The first diagnostic frequency candidate group consists of one or more frequencies extracted from the sideband waves of the meshing frequency of the gears constituting the current transmission stage. The second diagnostic frequency candidate group consists of one or more frequencies extracted from the sideband wave of the meshing frequency of the gears constituting the current transmission stage.

5. The transmission device monitoring system according to claim 2, characterized in that, The first diagnostic frequency candidate group consists of one or more frequencies extracted from the sideband wave of a frequency obtained by adding the power supply frequency of the motor's drive power supply to the meshing frequency of the gears constituting the current transmission stage. The second diagnostic frequency candidate group consists of one or more frequencies extracted from the sideband wave of the frequency obtained by adding the power supply frequency of the motor drive power supply to the meshing frequency of the gear constituting the current transmission stage.

6. The transmission device monitoring system according to claim 4, characterized in that, When the difference between the frequency extracted from the first diagnostic frequency candidate group and the frequency extracted from the second diagnostic frequency candidate group is set as the frequency difference Δf, Δf = the meshing frequency of the gear constituting the current transmission stage - the frequency extracted from the second diagnostic frequency candidate group × 2, or Δf = the meshing frequency of the gear constituting the current transmission stage.

7. The transmission device monitoring system according to claim 5, characterized in that, When the difference between the frequency extracted from the first diagnostic frequency candidate group and the frequency extracted from the second diagnostic frequency candidate group is set as the frequency difference Δf, Δf = the meshing frequency of the gear constituting the current transmission stage - the frequency extracted from the second diagnostic frequency candidate group × 2, or Δf = the meshing frequency of the gear constituting the current transmission stage.

8. The transmission device monitoring system according to claim 1, characterized in that, The abnormality diagnosis unit inputs the amplitude component of the diagnostic frequency into a model constructed from any one of a regression model, classification model, cluster model, or neural network model to calculate the abnormality degree, or calculates the abnormality degree of the transmission device based on the comparison result of the amplitude component of the diagnostic frequency with a threshold.

9. The transmission device monitoring system according to claim 1, characterized in that, The diagnostic frequency estimation unit estimates the speed of the motor by dividing the frequency obtained by parsing the current information related to the motor by the number of poles of the motor.

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