Servo motor operation state monitoring method and system

Abstract

The invention discloses an operation state monitoring method and system for a servo motor, and relates to the technical field of servo motor monitoring, and the method comprises the steps: obtaining a position deviation angle corresponding to a rotor at each preset operation time; meanwhile, according to the current of the rotating coordinate system, flux linkage deviations corresponding to the rotor at all preset operation durations are obtained, and according to the position deviation angle and the flux linkage deviations, the fault type of the rotor is diagnosed; the method comprises the following steps: performing deviation compensation on a stator according to a fault type of a rotor, calculating a major semi-axis and a minor semi-axis of an actual running track through ellipse fitting so as to obtain an eccentricity ratio, comparing the actual eccentricity ratio with a theoretical value, judging whether a fault signal is generated or not, and determining whether the fault signal is generated or not by combining flux linkage deviation calculation and real-time collection of current. The fault type of the rotor can be diagnosed more accurately, finally compensation is performed according to the fault type, the deviation of the rotor in operation is reduced through real-time compensation, and the operation stability and reliability of the motor are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of servo motor monitoring, and in particular relates to a method and a system for monitoring the operating status of a servo motor. Background Art

[0002] Permanent magnet direct-drive servo motor is a type of servo motor. Permanent magnet direct-drive servo system has the advantages of high efficiency and fast response due to the lack of reduction transmission mechanism, and is widely used in many fields.

[0003] The rotor of the servo motor is easily affected by many factors during low-speed operation, such as cogging torque, friction torque, harmonic torque, and load disturbance, which can easily cause position offset and unstable speed. These problems will not only reduce the operating efficiency of the motor, but may also cause the servo motor to be affected by cogging torque, friction torque, harmonic torque, and load disturbance, leading to speed fluctuations, creeping, and jamming, and even cause failures, seriously affecting the normal operation and service life of the servo motor; However, traditional motor fault detection methods mainly rely on simple monitoring of motor operating parameters, such as current, voltage and temperature. However, it is impossible to monitor slight changes in the rotor's operating trajectory in a timely manner, resulting in insufficient accuracy and timeliness of fault diagnosis. Based on this, a servo motor operating status monitoring method and system are proposed. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for monitoring the operating status of a servo motor, which solves the technical problem that slight changes in the rotor's operating trajectory cannot be monitored in a timely manner.

[0005] A method for monitoring the operating status of a servo motor comprises the following steps: Step 1: Obtain the theoretical positions of the rotor at each preset running time; Step 2: According to the actual positions of the rotor corresponding to each preset running time, curve fitting is performed on the actual running trajectory of the rotor to obtain the major semi-axis a and the minor semi-axis b in the actual running trajectory; Step 3: Calculate the eccentricity PB of the actual running track of the rotor according to the major semi-axis a and the minor semi-axis b in the actual running track, and compare it with the eccentricity PA of the theoretical running track of the rotor to determine and generate a fault signal; Step 4: When a fault signal is generated, the actual positions of the rotor corresponding to each preset operating duration are compared and analyzed with the corresponding theoretical positions to obtain the position deviation angles of the rotor corresponding to each preset operating duration. At the same time, the three-phase current is transformed to obtain the rotating coordinate system current, and the magnetic flux deviation corresponding to the rotor at each preset operating duration is obtained according to the rotating coordinate system current; Step Five: Diagnose the fault type of the rotor according to the position deviation angle and flux linkage deviation corresponding to the rotor at each preset operation duration. Step Six: Perform deviation compensation on the stator according to the fault type of the rotor.

[0006] As a further solution of the present invention: The specific method for obtaining the major semi-axis a and minor semi-axis b in the actual operation trajectory is as follows: Obtain the actual position θt of the rotor corresponding to each preset operation duration Tt. Take the motor installation center as the ellipse center O(0, 0), and set the fitting ellipse equation: , by minimizing the error function: ; Then, the major semi-axis a and minor semi-axis b in the actual operation trajectory can be obtained by obtaining and and solving, where t represents different preset operation durations, t = 1, 2,..., n, where n represents the total number of preset operation durations, n is a positive integer, and n is greater than or equal to 2.

[0007] The specific method for calculating the eccentricity PB of the actual operation trajectory of the rotor is as follows: Through the formula: ; Calculate the eccentricity PB of the actual operation trajectory.

[0008] As a further solution of the present invention: The specific method for determining the generation of a fault signal is as follows: Since the theoretical operation trajectory of the rotor is defaulted to a circular trajectory, its corresponding eccentricity PA is defaulted to 0. When PB is greater than PB + Y1, it is determined that a fault signal is generated. Otherwise, no processing is performed. Y1 is a preset threshold value, and its value is 0.025.

[0009] As a further solution of the present invention: The specific method for obtaining the position deviation angle corresponding to the rotor at each preset operation duration is as follows: Calculate the differences between the actual position and actual speed of the rotor corresponding to each preset operation duration and the theoretical position and theoretical speed of the rotor corresponding to each preset operation duration, and then obtain the position deviation angle △θt corresponding to the rotor at each preset operation duration.

[0010] As a further solution of the present invention: The specific method for obtaining the rotating coordinate system current after transforming the three-phase current is as follows: Collect the three-phase currents IAt, IBt, and ICt corresponding to the stator at each preset operation duration in real time. Through IAt = Iαt and , calculate the two-phase stationary coordinate system currents Iαt and Iβt after the Clarke transformation of the three-phase current; Then, through the formulas: Idt = Iαt×cosθt + Iqt×sinθt and Iqt = -Iαt×sinθt + Iqt×cosθt, the magnetic field component Idt and torque component Iqt in the Park rotating coordinate system current are calculated from the two-phase stationary coordinate system currents Iαt and Iβt.

[0011] As a further aspect of the present invention: The specific method for obtaining the magnetic flux deviations corresponding to the rotor at each preset operation duration is as follows: Through the formulas: Ψdt = Ldt×Idt + Ψf and Ψqt = Lqt×Iqt, the estimated magnetic field magnetic flux Ψdt and torque magnetic flux Ψqt corresponding to the rotor at each preset operation duration are calculated. ; The magnetic flux deviations △Ψt corresponding to the rotor at each preset operation duration are calculated, where Ψf is the permanent magnet magnetic flux, and Ldt and Lqt are the d-axis and q-axis inductances of the rotor at each preset operation duration.

[0012] As a further aspect of the present invention: The specific method for diagnosing the fault type of the rotor is as follows: The average value △θp of the maximum and minimum values in the deviation angle △θt is obtained. When △θp is greater than the preset threshold Y2, the fault type of the rotor is diagnosed as a position defect; the average value △Ψp of the maximum and minimum values in the magnetic flux deviation △Ψt of the deviation angle is obtained. When △Ψp is greater than the preset threshold Y3, the fault type of the rotor is diagnosed as a speed deviation defect. The specific method for compensating the stator according to the fault type of the rotor is as follows: When the fault type of the rotor is diagnosed as a position defect, the compensation current BA of the rotor is calculated through BA = MA×△θp, and the compensation current BA is added to the stator real-time current. When the fault type of the rotor is diagnosed as a speed deviation defect, the frequency adjustment amount △F of the rotor is calculated through the formula △F = MB×△Ψp; the adjusted frequency Fnew of the stator is calculated through Fnew = Fo + △F, and the adjusted frequency Fnew is applied to the stator current control. Fo is the actual frequency of the stator, and MA and MB are the compensation gain coefficient and frequency adjustment gain coefficient respectively.

[0013] An operating state monitoring system for a servo motor, which implements an operating state monitoring method for a servo motor, including: A data acquisition terminal, which obtains the theoretical position of the rotor at each preset operation duration; Actual operating trajectory acquisition, according to the actual positions corresponding to the rotor at each preset operation duration, the actual operating trajectory of the rotor is curve-fitted to obtain the major semi-axis a and minor semi-axis b in the actual operating trajectory; A fault signal determination terminal calculates the eccentricity PB of the actual operating trajectory of the rotor based on the major semi-axis a and minor semi-axis b in the actual operating trajectory, compares it with the eccentricity PA of the theoretical operating trajectory of the rotor, and generates a fault signal through determination; A fault type diagnosis terminal, when a fault signal is generated, compares and analyzes the actual positions corresponding to the rotor at each preset operating duration with the corresponding theoretical positions respectively, obtains the position deviation angles corresponding to the rotor at each preset operating duration respectively, simultaneously performs transformation processing on the three-phase current to obtain the rotating coordinate system current, and obtains the magnetic flux deviation corresponding to the rotor at each preset operating duration according to the rotating coordinate system current, and diagnoses the fault type of the rotor according to the position deviation angle and the magnetic flux deviation; A deviation compensation terminal compensates for the deviation of the stator according to the fault type of the rotor.

[0014] Compared with the prior art, the beneficial effects of the present invention are: In the present invention, by obtaining the theoretical position of the rotor under the preset operating duration and collecting the actual position data to obtain the actual operating trajectory, calculating the major semi-axis and minor semi-axis of the actual operating trajectory through ellipse fitting, and further obtaining the eccentricity, comparing the actual eccentricity with the theoretical value to determine whether a fault signal is generated. If a fault signal is generated, further through the combination of magnetic flux deviation calculation and real-time acquisition of current, the fault type of the rotor can be diagnosed more accurately. Finally, compensation is performed according to the fault type. Through real-time compensation, the deviation during the operation of the rotor is reduced, the operation stability and reliability of the motor are improved, and the service life of the equipment is extended. Description of the Drawings

[0015] Figure 1 is a schematic diagram of the method framework structure of the present invention; Figure 2 is a schematic diagram of the system framework structure of the present invention. Specific Embodiments

[0016] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Embodiment 1: Please refer to Figure 1 , this application provides a method for monitoring the operating state of a servo motor, including the following steps: Step 1: When the rotor rotates along a circular trajectory with a radius of R at a constant angular velocity ω (rad / s), obtain the theoretical positions corresponding to each preset operation duration Tt. According to the theoretical positions corresponding to each preset operation duration of the rotor, and taking the motor installation center as the center point when the motor rotates along a circular trajectory with a radius of R at a constant angular velocity, thereby achieving the acquisition of the ideal trajectory of the rotor, where t represents different preset operation durations, t = 1, 2, ……, n, where n represents the total number of preset operation durations, n is a positive integer, and n is greater than or equal to 2; It should be noted that the specific method for setting the preset operation duration Tt is as follows: By TA = 2π / ω, obtain the theoretical duration TA required for the rotor to rotate one circle along a circular trajectory with a radius of R at a constant angular velocity ω (rad / s). Select n time points at equal intervals within the theoretical duration TA to complete the setting of the preset operation duration Tt. Tt is greater than 0 and less than or equal to TA, and the time intervals between each preset operation duration Tt are equal. The preset operation duration Tt needs to cover at least one rotation period to provide accurate theoretical position data for subsequent fault diagnosis and help accurately monitor the actual operating state of the rotor.

[0018] Step 2: Collect the actual positions corresponding to each preset operation duration of the rotor. According to the actual positions corresponding to each preset operation duration of the rotor, perform curve fitting on the actual operating trajectory of the rotor, and calculate and obtain the major semi-axis a and minor semi-axis b in the actual operating trajectory. The specific method is as follows: Obtain the actual position θt corresponding to each preset operation duration Tt of the rotor, obtain the data points Qt(Tt, θt) corresponding to each preset operation duration of the rotor, and directly use them as the data points Qt(Tt, θt) in the rectangular coordinate system. At the same time, take the motor installation center as the ellipse center O(0, 0) for ellipse fitting to achieve the curve fitting of the actual operating trajectory of the rotor. The specific method is as follows: First, set the fitting ellipse equation: ; where a and b are the major semi-axis and minor semi-axis, and then through minimizing the error function: ; then we can obtain ; , solve to obtain the major semi-axis a and minor semi-axis b in the actual operating trajectory; Step 3: Calculate the eccentricity PB of the actual operating trajectory of the rotor according to the major semi-axis a and minor semi-axis b in the actual operating trajectory, compare it with the eccentricity PA of the theoretical operating trajectory of the rotor, and determine and generate a fault signal according to the analysis result. The specific method is as follows: Through the formula: ; Calculate the eccentricity PB of the actual operating trajectory. Since the theoretical operating trajectory of the rotor is defaulted to a circular trajectory, the corresponding eccentricity PA is defaulted to 0, that is, PA = 0. When PB is greater than PB + Y1, it is determined that there is a relatively obvious deviation between the actual operating trajectory of the rotor and the theoretical operating trajectory, and then a fault signal is generated. When PB is not greater than PB + Y1, no processing is done. Here, Y1 is a preset threshold value, and the specific value is determined by relevant staff according to actual needs. The value of Y1 is 0.025. Obtain the actual operating trajectory of the rotor according to the actual position and speed of the rotor corresponding to each preset operating duration. If there is a deviation between the actual operating trajectory and the ideal trajectory, it means that there is a deviation in the actual operation of the rotor, that is, the rotor may deviate from a circle during actual operation. By comparing the actual operating trajectory with the ideal trajectory, the deviation in the rotor operation can be intuitively found, providing a basis for fault diagnosis.

[0019] Step 4: When a fault signal is generated, compare and analyze the actual positions of the rotor corresponding to each preset operating duration with the corresponding theoretical positions respectively to obtain the position deviation angles of the rotor corresponding to each preset operating duration. At the same time, use a current sensor to collect the three-phase currents of the stator corresponding to each preset operating duration in real time, and obtain the rotating coordinate system current after transforming the three-phase currents. Then, obtain the magnetic flux deviation of the rotor corresponding to each preset operating duration according to the rotating coordinate system current. The specific method is as follows: First, calculate the differences between the actual positions and actual speeds of the rotor corresponding to each preset operating duration and the theoretical positions and theoretical speeds of the rotor corresponding to each preset operating duration, and then obtain the position deviation angles △θt of the rotor corresponding to each preset operating duration. The specific method of the position deviation angle is: △θt = θ0t - θ1t, where θ1t is the actual position of the rotor corresponding to each preset operating duration. Next, use a current sensor to collect the three-phase currents of the stator corresponding to each preset operating duration in real time, and mark them as IAt, IBt, and ICt respectively. Transform the three-phase currents of the stator corresponding to each preset operating duration into two-phase stationary coordinate system currents through Clarke-Park transformation, and then obtain the magnetic field components and torque components of the rotating coordinate system corresponding to the three-phase currents of the stator at each preset operating duration. The specific method is as follows: Then, perform Clarke transformation on the three-phase currents of the stator corresponding to each preset operating duration. Through IAt = Iαt and , calculate the two-phase stationary coordinate system currents \(I_{αt}\) and \(I_{βt}\) after the Clarke transformation of the three-phase currents; Then perform the Park transformation on the two-phase stationary coordinate system currents \(I_{αt}\) and \(I_{βt}\) after the Clarke transformation of the three-phase currents to obtain the rotating coordinate system currents \(I_{dt}\) and \(I_{qt}\) of the two-phase stationary coordinate system currents \(I_{αt}\) and \(I_{βt}\) after the Park transformation; Through the formulas: \(I_{dt}=I_{αt}×\cosθt + I_{qt}×\sinθt\) and \(I_{qt}=-I_{αt}×\sinθt + I_{qt}×\cosθt\), calculate the magnetic field component \(I_{dt}\) and torque component \(I_{qt}\) in the rotating coordinate system currents of the two-phase stationary coordinate system currents \(I_{αt}\) and \(I_{βt}\); Finally, according to the magnetic field component \(I_{dt}\) and torque component \(I_{qt}\) in the rotating coordinate system corresponding to the rotor at each preset operation duration respectively, obtain the magnetic flux deviation corresponding to the rotor at each preset operation duration respectively, and the specific method is: Through the formulas: \(\Psi_{dt}=L_{dt}×I_{dt}+\Psi_{f}\) and \(\Psi_{qt}=L_{qt}×I_{qt}\), calculate the estimated magnetic field magnetic flux \(\Psi_{dt}\) and torque magnetic flux \(\Psi_{qt}\) corresponding to the rotor at each preset operation duration respectively, where \(\Psi_{f}\) is the permanent magnet magnetic flux, and \(L_{dt}\) and \(L_{qt}\) are the d-axis and q-axis inductances of the rotor at each preset operation duration; Through ; calculate the magnetic flux deviation \(\Delta\Psi_{t}\) corresponding to the rotor at each preset operation duration respectively; Step Five: According to the position deviation angle \(\Delta\theta_{t}\) and magnetic flux deviation \(\Delta\Psi_{t}\) corresponding to the rotor at each preset operation duration respectively, diagnose the fault type of the rotor, and the specific method is: Obtain the mean value \(\Delta\theta_{p}\) of the maximum and minimum values in the deviation angle \(\Delta\theta_{t}\). When \(\Delta\theta_{p}\) is greater than the preset threshold \(Y2\), it means that the rotor has a position deviation, that is, the rotor has imbalance or asymmetry, resulting in a deviation in the rotor operation trajectory, or bearing damage or wear will cause the rotor to rotate unevenly, resulting in a position deviation. Furthermore, diagnose the fault type of the rotor as a position defect; Finally, obtain the mean value \(\Delta\Psi_{p}\) of the maximum and minimum values in the deviation angle magnetic flux deviation \(\Delta\Psi_{t}\). When \(\Delta\Psi_{p}\) is greater than the preset threshold \(Y3\), it means that the rotor speed has a deviation, and it is necessary to adjust the frequency of the stator current to ensure that the rotor returns to the normal speed in a short time. Then diagnose the fault type of the rotor as a speed deviation defect. The specific values of the preset thresholds \(Y2\) and \(Y3\) are determined by relevant personnel according to actual needs. Accurately diagnose the fault type, provide accurate information for subsequent deviation compensation, improve the pertinence and effectiveness of fault handling, can timely detect abnormal changes in the rotor operation trajectory, early warning of potential faults, and reduce the risk of equipment damage.

[0020] Embodiment 2: As the second embodiment of the present invention, when the present application is specifically implemented, compared with Embodiment 1, it further includes Step 6: Step 6: Perform deviation compensation on the stator according to the fault type of the rotor. The specific method is as follows: When the fault type of the rotor is diagnosed as a position defect, compensate for the position deviation of the rotor. The specific method is as follows: Obtain the compensation current BA of the rotor by calculating BA = MA × △θp, and add the compensation current BA to the real-time current of the stator to reduce the influence of the position deviation. MA is the compensation gain coefficient; When the fault type of the rotor is diagnosed as a rotational speed deviation defect, compensate for the rotational speed deviation of the rotor. Obtain the frequency adjustment amount △F of the rotor by calculating with the formula △F = MB × △Ψp; MB is the frequency adjustment gain coefficient; Mark the actual frequency of the stator as Fo, calculate and obtain the adjusted frequency Fnew of the stator by Fnew = Fo + △F, and apply the adjusted frequency Fnew to the stator current control to reduce the rotational speed deviation, effectively diagnose the fault type of the rotor, and perform corresponding deviation compensation according to the fault type, thereby improving the operation stability and reliability of the motor; Among them, both the compensation gain coefficient MA and the frequency adjustment gain coefficient MB are preset values, and the specific values are adjusted by relevant personnel according to actual needs; Through real-time compensation, reduce the deviation during the operation of the rotor, improve the operation stability and reliability of the motor, and extend the service life of the equipment; Combined with the calculation of the flux linkage deviation and the real-time acquisition of the current, the solution can more accurately diagnose the fault type of the rotor. Obtain the actual operation trajectory by acquiring the theoretical position of the rotor under the preset operation duration and collecting the actual position data, calculate the major axis and minor axis of the actual operation trajectory through ellipse fitting, and then obtain the eccentricity. Compare the actual eccentricity with the theoretical value to determine whether a fault signal is generated. If a fault signal is generated, further analyze the position deviation angle and the flux linkage deviation to determine the fault type. Finally, the deviation compensation terminal performs compensation according to the fault type, such as adjusting the current in case of a position defect and adjusting the frequency in case of a rotational speed deviation, to reduce the influence of the deviation. Through real-time compensation, reduce the deviation during the operation of the rotor, improve the operation stability and reliability of the motor, and extend the service life of the equipment.

[0021] This solution can monitor the operation state of the rotor in real time, detect and handle faults in time, reduce the risk of equipment damage, extend the service life of the motor, improve the operation stability and reliability of the motor through accurate fault diagnosis and compensation measures, reduce the maintenance cost, and enhance the adaptability of the equipment under complex working conditions.

[0022] Embodiment 3: As the third embodiment of the present invention, please refer to Figure 2, a running state monitoring system for a servo motor is provided. This system is used to implement the previously disclosed running state monitoring method for a servo motor, specifically including: A data acquisition terminal obtains the theoretical positions corresponding to each preset running duration Tt when the rotor rotates along a circular trajectory with a radius of R at a constant angular velocity ω (rad / s) through a resolver, and based on the theoretical positions corresponding to each preset running duration of the rotor, and taking the motor installation center as the center point when the motor rotates along a circular trajectory with a radius of R at a constant angular velocity, thereby obtaining the ideal trajectory of the rotor. An actual running trajectory acquisition terminal collects the actual positions corresponding to each preset running duration of the rotor through the data acquisition terminal, performs curve fitting on the actual running trajectory of the rotor based on the actual positions corresponding to each preset running duration of the rotor, and calculates and obtains the major semi-axis a and minor semi-axis b in the actual running trajectory. A fault signal determination terminal calculates the eccentricity PB of the actual running trajectory of the rotor based on the major semi-axis a and minor semi-axis b in the actual running trajectory, compares and analyzes it with the eccentricity PA of the theoretical running trajectory of the rotor, and determines and generates a fault signal according to the analysis result. A fault type diagnosis terminal, when a fault signal is generated, compares and analyzes the actual positions corresponding to each preset running duration of the rotor with the corresponding theoretical positions respectively, obtains the position deviation angles corresponding to each preset running duration of the rotor, and at the same time, a current sensor is used to collect the three-phase currents corresponding to each preset running duration of the stator in real time, and obtains the magnetic flux deviation corresponding to each preset running duration of the rotor according to the three-phase currents. The fault type of the rotor is diagnosed according to the position deviation angle and the magnetic flux deviation. The specific method is as follows: In the position deviation angle acquisition unit, calculate the differences between the actual positions and actual rotational speeds corresponding to each preset running duration of the rotor and the theoretical positions and theoretical rotational speeds corresponding to each preset running duration of the rotor, thereby obtaining the position deviation angles △θt corresponding to each preset running duration of the rotor. In the current acquisition unit, a current sensor is used to collect the three-phase currents corresponding to each preset running duration of the stator in real time, and they are respectively marked as IAt, IBt, and ICt. The three-phase currents corresponding to each preset running duration of the stator are transformed by Clarke-Park transformation into two-phase stationary coordinate system currents, thereby obtaining the magnetic field components and torque components of the rotating coordinate system corresponding to the three-phase currents of the stator at each preset running duration. Within the flux linkage deviation acquisition unit, according to the magnetic field component Idt and torque component Iqt in the rotating coordinate system corresponding to the rotor at each preset operation duration, the flux linkage deviation corresponding to the rotor at each preset operation duration is obtained; Within the fault type diagnosis unit, according to the position deviation angle △θt and flux linkage deviation △Ψt corresponding to the rotor at each preset operation duration, the fault type of the rotor is diagnosed; the mean value △θp of the maximum and minimum values in the deviation angle △θt is obtained. When △θp is greater than the preset threshold Y2, it indicates that the rotor has a position deviation, that is, the rotor has imbalance or asymmetry, resulting in a deviation in the rotor operation trajectory, or bearing damage or wear will cause the rotor to rotate unstably, thus generating a position deviation. Furthermore, the fault type of the rotor is diagnosed as a position defect; The mean value △Ψp of the maximum and minimum values in the flux linkage deviation △Ψt is obtained. When △Ψp is greater than the preset threshold Y3, it indicates that there is a deviation in the rotor speed, and the frequency of the stator current needs to be adjusted to ensure that the rotor returns to the normal speed within a short time. Then, the fault type of the rotor is diagnosed as a speed deviation defect. The specific values of the preset thresholds Y2 and Y3 are determined by relevant personnel according to actual requirements.

[0023] Deviation compensation terminal. When the fault type of the rotor is diagnosed as a position defect, the position deviation of the rotor is compensated. The compensation current BA of the rotor is calculated through BA = MA×△θp, and the compensation current BA is added to the stator current to reduce the influence of the position deviation. MA is the compensation gain coefficient; when the fault type of the rotor is diagnosed as a speed deviation defect, the speed deviation of the rotor is compensated. The frequency adjustment amount △F of the rotor is calculated through the formula △F = MB×△Ψp; MB is the frequency adjustment gain coefficient; The actual frequency of the stator is marked as Fo, and the adjusted frequency Fnew of the stator is calculated through Fnew = Fo + △F. The adjusted frequency Fnew is applied to the stator current control to reduce the speed deviation, effectively diagnose the fault type of the rotor, and perform corresponding deviation compensation according to the fault type, thereby improving the operation stability and reliability of the motor; Among them, both the compensation gain coefficient MA and the frequency adjustment gain coefficient MB are preset values, and the specific values are adjusted by relevant personnel according to actual requirements.

[0024] Embodiment 4: As Embodiment 4 of the present invention, when this application is specifically implemented, compared with Embodiment 1, Embodiment 2, and Embodiment 3, the technical solution of this embodiment lies in combining the solutions of the above Embodiment 1, Embodiment 2, and Embodiment 3 for implementation.

[0025] The above formulas are all dimensionless and take their numerical calculations. The formula is a formula obtained by collecting a large amount of data for software simulation to get the closest to the actual situation. The preset parameters and threshold selection in the formula are set by those skilled in the art according to the actual situation.

[0026] As described above, it is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the said claims.

Claims

1. A method for monitoring the operating state of a servo motor, characterized in that, It includes the following steps: Step 1: Obtain the theoretical positions corresponding to the rotor at each preset running duration respectively; Step 2: According to the actual positions corresponding to the rotor at each preset running duration respectively, perform curve fitting on the actual running trajectory of the rotor to obtain the major semi-axis a and minor semi-axis b in the actual running trajectory; Step 3: Calculate the eccentricity PB of the actual running trajectory of the rotor based on the major semi-axis a and minor semi-axis b in the actual running trajectory, and compare it with the eccentricity PA of the theoretical running trajectory of the rotor to generate a fault signal; Step 4: When a fault signal is generated, compare and analyze the actual positions corresponding to the rotor at each preset running duration respectively with the corresponding theoretical positions to obtain the position deviation angles corresponding to the rotor at each preset running duration respectively. At the same time, perform transformation processing on the three-phase current to obtain the rotating coordinate system current, and obtain the flux linkage deviation corresponding to the rotor at each preset running duration based on the rotating coordinate system current; Step 5: Diagnose the fault type of the rotor according to the position deviation angles and flux linkage deviations corresponding to the rotor at each preset running duration respectively; Step 6: Perform deviation compensation on the stator according to the fault type of the rotor.

2. The operating state monitoring method of a servo motor according to claim 1, characterized in that The specific method for obtaining the major semi-axis a and minor semi-axis b in the actual running trajectory is: Obtain the actual position θt corresponding to the rotor at each preset running duration Tt, take the motor installation center as the ellipse center O(0, 0), and set the fitting ellipse equation: , by minimizing the error function: ; then, by obtaining and , solve to obtain the major semi-axis a and the minor semi-axis b in the actual running trajectory, where t represents different preset running durations, t = 1, 2, ……, n, where n represents the total number of preset running durations, n is a positive integer, and n is greater than or equal to 2.

3. The operating state monitoring method of a servo motor according to claim 2, characterized in that, The specific method for calculating the eccentricity PB of the actual running trajectory of the rotor is: Through the formula: ; the eccentricity PB of the actual operating trajectory is calculated and obtained.

4. A method for monitoring the operating state of a servo motor according to claim 3, characterized in that, The specific method for determining and generating a fault signal is: Since the theoretical running trajectory of the rotor is defaulted to a circular trajectory, its corresponding eccentricity PA is defaulted to 0. When PB is greater than PB + Y1, it is determined that a fault signal is generated. Otherwise, no processing is performed. Y1 is a preset threshold value, and its value is 0.

025.

5. A method for monitoring the operating state of a servo motor according to claim 4, characterized in that, The specific method for obtaining the position deviation angles corresponding to the rotor at each preset running duration respectively is: Calculate the differences between the actual positions and actual rotational speeds corresponding to the rotor at each preset running duration respectively and the theoretical positions and theoretical rotational speeds corresponding to the rotor at each preset running duration respectively, and then obtain the position deviation angles △θt corresponding to the rotor at each preset running duration respectively.

6. The operating state monitoring method of a servo motor according to claim 5, characterized in that, The specific method for performing transformation processing on the three-phase current to obtain the rotating coordinate system current is: The three-phase currents IAt, IBt, and ICt corresponding to the stator at each preset operating duration are respectively collected in real time. Through IAt = Iαt and , the two-phase stationary coordinate system currents Iαt and Iβt after the Clarke transformation of the three-phase currents are calculated and obtained; Then, through the formulas: Idt = Iαt×cosθt + Iqt×sinθt and Iqt = -Iαt×sinθt + Iqt×cosθt, calculate the magnetic field component Idt and torque component Iqt in the Park's rotating coordinate system current of the two-phase stationary coordinate system currents Iαt and Iβt.

7. The operating state monitoring method of a servo motor according to claim 6, characterized in that The specific method for obtaining the flux linkage deviations corresponding to the rotor at each preset running duration respectively is: The estimated magnetic flux linkage Ψdt and torque magnetic flux linkage Ψqt corresponding to the rotor at each preset operation duration are calculated through the formulas: Ψdt = Ldt × Idt + Ψf and Ψqt = Lqt × Iqt. Through ; the magnetic flux linkage deviation △Ψt corresponding to the rotor at each preset operation duration is calculated, where Ψf is the permanent magnet magnetic flux linkage, and Ldt and Lqt are the d-axis and q-axis inductances of the rotor at each preset operation duration.

8. A method for monitoring the operating state of a servo motor according to claim 7, characterized in that, The specific method for diagnosing the fault type of the rotor is: Obtain the mean value △θp of the maximum and minimum values in the deviation angle △θt. When △θp is greater than the preset threshold Y2, diagnose the fault type of the rotor as a position defect; Obtain the mean value △Ψp of the maximum and minimum values in the deviation angle flux linkage deviation △Ψt. When △Ψp is greater than the preset threshold Y3, then diagnose the fault type of the rotor as a rotational speed deviation defect.

9. The operating state monitoring method of a servo motor according to claim 8, characterized in that, The specific method for performing deviation compensation on the stator according to the fault type of the rotor is: When the fault type diagnosis of the rotor is a position defect, the compensation current BA of the rotor is calculated through BA = MA × △θp, and the compensation current BA is added to the real-time current of the stator. When the fault type diagnosis of the rotor is a speed deviation defect, the frequency adjustment amount △F of the rotor is calculated through the formula △F = MB × △Ψp. The adjusted frequency Fnew of the stator is calculated through Fnew = Fo + △F, and the adjusted frequency Fnew is applied to the stator current control. Fo is the actual frequency of the stator, and MA and MB are the compensation gain coefficient and the frequency adjustment gain coefficient respectively.

10. An operating state monitoring system for a servo motor, characterized in that, This system implements the method for monitoring the operating state of a servo motor according to any one of claims 1-9, including: A data acquisition terminal, which obtains the theoretical position of the rotor at each preset operating duration; Actual operating trajectory acquisition: According to the actual positions corresponding to the rotor at each preset operating duration, curve fitting is performed on the actual operating trajectory of the rotor to obtain the major semi-axis a and the minor semi-axis b in the actual operating trajectory; A fault signal determination terminal, which calculates the eccentricity PB of the actual operating trajectory of the rotor according to the major semi-axis a and the minor semi-axis b in the actual operating trajectory, and compares it with the eccentricity PA of the theoretical operating trajectory of the rotor to generate a fault signal; A fault type diagnosis terminal, when a fault signal is generated, compares and analyzes the actual positions corresponding to the rotor at each preset operating duration with the corresponding theoretical positions respectively to obtain the position deviation angles corresponding to the rotor at each preset operating duration. At the same time, after transforming the three-phase current, the rotating coordinate system current is obtained, and the flux linkage deviation corresponding to the rotor at each preset operating duration is obtained according to the rotating coordinate system current. The fault type of the rotor is diagnosed according to the position deviation angle and the flux linkage deviation; A deviation compensation terminal, which performs deviation compensation on the stator according to the fault type of the rotor.

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