Planetary reducer gear shaft machining method capable of reducing machining errors

Abstract

The invention relates to the technical field of grinding processes, and provides a planetary reducer gear shaft machining method capable of reducing machining errors, which comprises the following steps: setting an initial value of a PI coefficient, adjusting grinding parameters of grinding treatment by using a PID control algorithm, and collecting surface roughness before and after the grinding treatment and a vibration value of the grinding treatment; determining the machining effect stability degree of the grinding treatment and the predicted value of the surface roughness degree of the next grinding treatment; a PI coefficient reference value, vibration-grinding precision correlation and PI coefficient parameters of grinding treatment are determined; and according to the PI coefficient reference value of grinding treatment, the PI coefficient value, the vibration-grinding precision correlation and the PI coefficient parameter, a PI coefficient optimization value is determined, and planetary reducer gear shaft machining is achieved according to the PI coefficient optimization value. Cutting machining errors can be reduced, and the precision of the planetary reducer gear shaft is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the grinding process technical field, in particular to a planetary reducer gear shaft machining method for reducing machining errors. BACKGROUND

[0002] Reducing the machining errors of the planetary reducer gear shaft can improve the meshing performance, improve the transmission efficiency, meet the high-end mechanical requirements, and reduce the maintenance cost. The grinding quality of the surface of the gear shaft, which is the core component of the planetary reducer, directly affects the overall performance. In order to ensure the grinding quality of the surface of the gear shaft, a fixed PI coefficient is generally used to adjust the grinding parameters through a PID control algorithm.

[0003] However, the surface roughness of different planetary reducer gear shafts processed by different pre-processing processes is not the same. Using a fixed PI coefficient to adjust the grinding parameters cannot adapt to the dynamic changes of the surface roughness of different planetary reducer gear shafts, which may lead to insufficient grinding or excessive grinding, and affect the machining accuracy of the planetary reducer gear shaft after the grinding parameter adjustment. SUMMARY

[0004] The application provides a planetary reducer gear shaft machining method for reducing machining errors to solve the problem that the grinding parameter adjustment cannot adapt to different surface roughness of different planetary reducer gear shafts, which may lead to insufficient grinding or excessive grinding and insufficient machining accuracy. The technical scheme adopted is as follows: One embodiment of the application provides a planetary reducer gear shaft machining method for reducing machining errors, which comprises the following steps: An initial value of a PI coefficient of a PID control algorithm is set, the grinding parameters of grinding processing are adjusted using the PID control algorithm, the surface roughness of a first preset number of planetary reducer gear shafts before and after grinding processing is continuously collected, and the vibration value of the grinding processing is collected; The grinding machining effect of the same grinding processing is determined according to the difference between the surface roughness before and after the same grinding processing, the machining effect stability of the last grinding processing in all grinding processes and the predicted value of the surface roughness after the next grinding processing after the last grinding processing in all grinding processes are determined according to the difference between the grinding machining effects of the first preset number of continuous grinding processes and the difference between the surface roughness; The PI coefficient reference value of the next grinding treatment of the last grinding treatment in all grinding treatments and the vibration-grinding accuracy correlation and PI coefficient parameters of the last grinding treatment in all grinding treatments are determined according to the surface roughness before and after the first preset number of times of grinding treatment, the grinding processing effect of the grinding treatment, the stability degree of the processing effect, the vibration value, the value of the PI coefficient in the grinding treatment, the predicted value of the surface roughness after the next grinding treatment of the last grinding treatment in all grinding treatments. The PI coefficient optimization value of the next grinding treatment of the grinding treatment is determined according to the PI coefficient reference value of the grinding treatment, the value of the PI coefficient, the vibration-grinding accuracy correlation and the PI coefficient parameters, and the planetary reducer gear shaft is processed according to the PI coefficient optimization value.

[0005] Further, the vibration value of the grinding treatment is specifically: The mean value of all vibration data of the same grinding treatment is recorded as the vibration value of the grinding treatment.

[0006] Further, the specific determination method of the grinding processing effect of the grinding treatment is: The absolute value of the difference between the surface roughness before and after the same grinding treatment is recorded as the roughness difference of the same grinding treatment, and the ratio of the roughness difference of the same grinding treatment to the surface roughness after the treatment is recorded as the grinding processing effect of the same grinding treatment.

[0007] Further, the specific determination method of the stability degree of the processing effect of the grinding treatment is: The variance of the grinding processing effect of the first preset number of consecutive planetary reducer gear shafts in the grinding treatment is recorded as the first variance of the last grinding treatment in all grinding treatments. The variance of the surface roughness after the grinding treatment of the first preset number of consecutive planetary reducer gear shafts is recorded as the second variance of the last grinding treatment in all grinding treatments. The positive correlation processing result of the first variance and the second variance of the grinding treatment is recorded as the stability degree of the processing effect of the last grinding treatment in all grinding treatments.

[0008] Further, the specific determination method of the predicted value of the surface roughness after the next grinding treatment of the last grinding treatment in all grinding treatments is: The predicted value of the surface roughness after the next grinding treatment is obtained according to the surface roughness of the first preset number of planetary reducer gear shafts after the grinding treatment.

[0009] Further, the acquisition method of the PI coefficient reference value is: According to the surface roughness before and after the grinding treatment, the grinding processing effect of the grinding treatment, the stability of the processing effect, and the predicted value of the surface roughness after the next grinding treatment of the last grinding treatment in all the grinding treatments, the first preset number of grinding treatments is clustered to obtain a grinding first cluster; The average value of the PI coefficient values in the process of all the grinding treatments in the grinding first cluster where the last grinding treatment is located is recorded as the PI coefficient reference value of the next grinding treatment of the last grinding treatment in all the grinding treatments.

[0010] Further, the specific calculation method of the vibration-grinding precision correlation is: According to the surface roughness before and after the grinding treatment, the vibration value of the grinding treatment, and the PI coefficient value in the process of the grinding treatment, the first preset number of grinding treatments is clustered to obtain a grinding second cluster; According to the vibration values of all the grinding treatments in the grinding second cluster where the last grinding treatment is located, a vibration value sequence is constructed. According to the surface roughness after all the grinding treatments in the grinding second cluster where the last grinding treatment is located, a post-processing surface roughness sequence is constructed. The absolute value of the correlation coefficient of the vibration value sequence and the post-processing surface roughness sequence is recorded as the vibration-grinding precision correlation of the last grinding treatment in all the grinding treatments.

[0011] Further, the specific determination method of the PI coefficient parameter is: According to the surface roughness before different grinding treatments, the vibration values of the first preset number of collected grinding treatments are clustered to obtain a grinding third cluster. The average value of the vibration values of all the grinding treatments included in the grinding third cluster is recorded as the vibration average value of the grinding third cluster. According to the vibration average values of all the grinding third clusters, a vibration threshold value is determined, and the average value of the PI coefficient values of all the grinding treatments included in the grinding third cluster whose vibration average value is less than the vibration threshold value is recorded as the PI coefficient parameter of the last grinding treatment in all the grinding treatments.

[0012] Further, the calculation formula of the PI coefficient optimization value is: wherein, PIcofopt represents the PI coefficient optimization value of the next grinding treatment of the last grinding treatment in all the grinding treatments; PIcorr represents the vibration-grinding precision correlation of the last grinding treatment in all the grinding treatments; PIcof represents the PI coefficient value of the last grinding treatment in all the grinding treatments. PI coefficient reference value of the next grinding process representing the last grinding process among all grinding processes; PI coefficient parameter of the last grinding process among all grinding processes.

[0013] Further, the planetary reducer gear shaft machining according to the PI coefficient optimization value comprises the specific method that: The PI coefficient optimization value of the next grinding process representing the last grinding process among all grinding processes is taken as the value of the PI coefficient of the PID control algorithm of the grinding process, and the grinding parameters of the planetary reducer gear shaft machining are adjusted by using the PID control algorithm.

[0014] The beneficial effects of the present application are: The present application firstly evaluates the machining effect of the grinding process on the planetary reducer gear shaft according to the difference of the surface roughness before and after the same grinding process, obtains the grinding machining effect and the machining effect stability degree of the grinding process, the machining effect of the grinding process on the continuous first preset number of planetary reducer gear shafts is better when the machining effect stability degree of the grinding process is greater, the value of the PI coefficient of the PID control algorithm selected at this time is more reasonable, and the adjustment of the value of the PI coefficient is not needed, and the prediction value of the surface roughness after the next grinding process is determined; in order to better obtain a more appropriate value of the PI coefficient of the PID control algorithm, improve the machining precision, and reduce the machining error, the relationship between the vibration value of the grinding process and the accuracy of the grinding process is evaluated, the vibration-grinding accuracy correlation is obtained, and the PI coefficient reference value and the PI coefficient parameter are determined according to the evaluation value of each grinding process; finally, the PI coefficient optimization value of the next grinding process of the grinding process is determined according to the PI coefficient reference value, the value of the PI coefficient, the vibration-grinding accuracy correlation and the PI coefficient parameter, the planetary reducer gear shaft machining is realized according to the PI coefficient optimization value, the problem that the grinding parameter adjustment cannot be self-adapted to different surface roughness of different planetary reducer gear shafts is solved, the problems of insufficient grinding or excessive grinding are easily caused, the machining precision is insufficient, the cutting machining error is reduced, and the precision of the planetary reducer gear shaft is improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1A planetary reducer gear shaft machining method flowchart for reducing machining error provided by an embodiment of the present application; Figure 2 A grinding machining effect acquisition flowchart provided by an embodiment of the present application. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0018] Please refer to Figure 1 which shows a planetary reducer gear shaft machining method flowchart for reducing machining error provided by an embodiment of the present application. The method comprises the following steps: Step S001, set initial values of PI coefficients of a PID control algorithm, use the PID control algorithm to adjust grinding parameters of grinding processing, continuously collect surface roughness of the first preset number of planetary reducer gear shafts before and after grinding processing, and vibration value of grinding processing.

[0019] Set initial values of PI coefficients of a PID control algorithm, use the PID control algorithm to adjust grinding parameters, and continuously perform grinding processing on the first preset number of planetary reducer gear shafts.

[0020] Use a laser roughness sensor to collect surface roughness of the planetary reducer gear shaft before and after grinding processing. Use a vibration sensor to collect vibration data of a grinding wheel spindle during grinding processing of the planetary reducer gear shaft, and take the mean value of all vibration data of the same grinding processing of the planetary reducer gear shaft as the vibration value of the grinding processing.

[0021] Preferably, in an embodiment of the present application, the data sampling frequency is 1 kHz when collecting vibration data. In actual application, as other implementation manners, the implementer can determine the value of the sampling frequency according to the actual situation, and the present application does not make special limitation.

[0022] The surface roughness of the first preset number of planetary reducer gear shafts before and after the grinding process and the vibration value of the grinding process are continuously collected, and according to these data, the value of the PI coefficient of the PID control algorithm used in the grinding process of the next planetary reducer gear shaft is determined, so that the next grinding process is more in line with the requirements of the surface roughness of the planetary reducer gear shaft, and the problems of insufficient grinding or excessive grinding are avoided. The value of the first preset number in this embodiment is 50.

[0023] At this point, the surface roughness of the planetary reducer gear shaft before and after the grinding process and the vibration value of the grinding process are obtained.

[0024] Step S002, according to the difference between the surface roughness before and after the same grinding process, determine the grinding processing effect of the same grinding process, according to the difference between the grinding processing effect of the continuous first preset number of times of grinding process and the difference between the surface roughness, determine the processing effect stability of the last grinding process in all grinding processes and the predicted value of the surface roughness after the next grinding process after the last grinding process in all grinding processes.

[0025] In order to adjust the grinding parameters in time, the value of the PI coefficient of the PID control algorithm needs to be adjusted in time according to the grinding processing effect of the planetary reducer gear shaft being ground, so that the next grinding process is more in line with the requirements of the surface roughness of the planetary reducer gear shaft, and the problems of insufficient grinding or excessive grinding are avoided.

[0026] According to the difference between the surface roughness before and after the same grinding process, determine the grinding processing effect of the same grinding process.

[0027] The absolute value of the difference between the surface roughness before and after the same grinding process is recorded as the roughness difference of the same grinding process, and the ratio of the roughness difference of the same grinding process to the surface roughness after the process is recorded as the grinding processing effect of the same grinding process.

[0028] The greater the grinding processing effect of the planetary reducer gear shaft in the grinding process, the better the processing effect of the planetary reducer gear shaft in the grinding process. The grinding processing effect acquisition flow chart is shown in Figure 2

[0029] ​The variance of the grinding processing effect of the continuous first preset number of planetary reducer gear shafts in the grinding processing is recorded as the first variance of the last grinding processing in all grinding processing. The variance of the surface roughness of the continuous first preset number of planetary reducer gear shafts after the grinding processing is recorded as the second variance of the last grinding processing in all grinding processing. The positive correlation processing result of the first variance and the second variance of the grinding processing is recorded as the processing effect stability degree of the last grinding processing in all grinding processing.

[0030] It can be understood that the first variance and the second variance of the grinding processing are positively correlated, that is, the first variance and the second variance of the grinding processing are respectively positively correlated with the processing effect stability degree of the grinding processing. It can be understood that the positive correlation of the present application refers to the relationship between the independent variable and the dependent variable, the independent variable is the first variance and the second variance of the grinding processing, and the dependent variable is the processing effect stability degree of the grinding processing. The positive correlation is that the dependent variable increases (decreases) with the increase (decrease) of the independent variable, which can be an additive relationship, a multiplication relationship, etc.

[0031] Preferably, as an embodiment of the present application, the reciprocal of the normalized value of the mean of the first variance and the second variance of the grinding processing is recorded as the processing effect stability degree of the last grinding processing in all grinding processing.

[0032] In the present embodiment, the sigmoid function is used to calculate the normalized value, wherein the sigmoid function is a known technology and will not be described here. As other implementation manners, the implementer can use other methods of the prior art, such as tanh function, etc. In the process of reciprocal calculation, in order to avoid the case that the denominator is zero, a preset value needs to be added to the denominator. The value of the preset value is 0.01 in the embodiment.

[0033] The greater the processing effect stability degree of the grinding processing is, the better the processing effect of the grinding processing of the continuous first preset number of planetary reducer gear shafts is, and at this time, the value of the PI coefficient of the selected PID control algorithm is more reasonable and does not need to be adjusted.

[0034] It should be understood that when the grinding processing before the grinding processing is less than the first preset number of times, the surface roughness before and after the historical grinding processing and the vibration value of the grinding processing are used to calculate the processing effect stability degree of the grinding processing.

[0035] The surface roughness degree of the first preset number of planetary reducer gear shafts after the grinding treatment is sequentially arranged, a surface roughness degree sequence is obtained, a time series prediction algorithm is used to process the surface roughness degree sequence, and a predicted value of the surface roughness degree after the next grinding treatment of the last grinding treatment in all grinding treatments is obtained.

[0036] In the actual application process, as other implementation manners, on the basis of achieving the purpose of data prediction, the implementer can use other methods such as the autoregressive model AR, the moving average model MA, the autoregressive moving average model, the seasonal autoregressive integrated moving average model SARIMA, and the exponential smoothing method to realize data prediction.

[0037] At this point, the processing effect stability degree of the grinding treatment and the predicted value of the surface roughness degree after the next grinding treatment are obtained.

[0038] Step S003, according to the surface roughness degree before and after the first preset number of times of grinding treatment, the grinding processing effect of the grinding treatment, the processing effect stability degree, the vibration value, the value of the PI coefficient in the process of the grinding treatment, the predicted value of the surface roughness degree after the next grinding treatment of the grinding treatment, the PI coefficient reference value of the next grinding treatment of the last grinding treatment in all grinding treatments is determined, and the vibration-grinding accuracy correlation and the PI coefficient parameter of the last grinding treatment in all grinding treatments are determined.

[0039] The surface roughness degree before and after the grinding treatment, the grinding processing effect of the grinding treatment, the processing effect stability degree, and the predicted value of the surface roughness degree after the next grinding treatment of the grinding treatment are sequentially arranged, a first feature sequence of the grinding treatment is obtained, the Euclidean distance between the first feature sequences of different grinding treatments is taken as the distance between different grinding treatments, the first preset number of times of grinding treatment is clustered, and a first clustering cluster is obtained.

[0040] The average value of the value of the PI coefficient in the process of all grinding treatments in the first grinding clustering cluster is recorded as the PI coefficient reference value of the next grinding treatment of the last grinding treatment in all grinding treatments.

[0041] The rotation speed and the feed amount of the grinding tool will affect the vibration data of the grinding process. When the vibration of the grinding treatment is larger, the grinding accuracy of the grinding treatment is lower. In order to better obtain the value of the PI coefficient of the PID control algorithm, improve the processing accuracy, and reduce the processing error, the relationship between the vibration value of the grinding treatment and the accuracy of the grinding treatment is evaluated.

[0042] The surface roughness before and after the grinding process, the vibration value of the grinding process, and the value of the PI coefficient in the grinding process are arranged in sequence to obtain a second feature sequence of the grinding process. The Euclidean distance between the second feature sequences of different grinding processes is taken as the distance between different grinding processes. The first preset number of grinding processes is clustered to obtain a second grinding cluster.

[0043] The vibration values of all grinding processes in the second grinding cluster of the last grinding process are arranged in order of the grinding process to obtain a vibration value sequence. The surface roughness after all grinding processes in the second grinding cluster of the last grinding process is arranged in order of the grinding process to obtain a post-processing surface roughness sequence. The absolute value of the correlation coefficient between the vibration value sequence and the post-processing surface roughness sequence is recorded as the vibration-grinding precision correlation of the last grinding process in all grinding processes.

[0044] In this embodiment, the Pearson correlation coefficient is used to calculate the correlation coefficient between the vibration value sequence and the post-processing surface roughness sequence, i.e., the Pearson correlation coefficient is used to evaluate the correlation between the two sequences. As other embodiments, for the purpose of measuring the correlation between two sequences, the implementer can use other methods such as cosine similarity, Spearman correlation coefficient, etc. in the prior art to obtain the correlation between two sequences, and the present application does not make special restrictions.

[0045] The greater the vibration-grinding precision correlation is, the more significant the correlation between the vibration value of the grinding process and the precision of the grinding process is. When determining the value of the PI coefficient of the PID control algorithm of the next grinding process, the influence of the vibration value of the grinding process should be considered more.

[0046] The Euclidean distance between the surface roughness before different grinding processes is taken as the distance between different grinding processes. The vibration values of the first preset number of collected grinding processes are clustered to obtain a third grinding cluster. The mean value of the vibration values of all grinding processes contained in the third grinding cluster is recorded as the vibration mean value of the third grinding cluster. The vibration threshold is obtained by processing the vibration mean values of all third grinding clusters using the maximum inter-cluster variance method. The mean value of the values of the PI coefficient of the grinding processes contained in all third grinding clusters whose vibration mean values are less than the vibration threshold is recorded as the PI coefficient parameter of the last grinding process in all grinding processes.

[0047] In the embodiment, the DBSCAN clustering algorithm is used for clustering. In actual application, other methods such as the Mean Shift clustering algorithm, the OPTICS clustering algorithm, the Gaussian Mixture Models clustering algorithm, and the Spectral Clustering algorithm can be used for clustering on the basis of achieving the purpose of clustering, and the application is not specially limited.

[0048] At this point, the PI coefficient reference value of the next grinding process of the last grinding process in all grinding processes is obtained, and the vibration-grinding accuracy correlation and the PI coefficient parameter of the last grinding process in all grinding processes are obtained.

[0049] In step S004, the PI coefficient optimization value of the next grinding process of the grinding process is determined according to the PI coefficient reference value of the grinding process, the value of the PI coefficient, the vibration-grinding accuracy correlation, and the PI coefficient parameter, and the planetary reducer gear shaft is processed according to the PI coefficient optimization value.

[0050] According to the PI coefficient reference value of the next grinding process of the last grinding process in all grinding processes, and the value of the PI coefficient, the vibration-grinding accuracy correlation, and the PI coefficient parameter of the last grinding process in all grinding processes, the PI coefficient optimization value of the next grinding process of the last grinding process in all grinding processes is determined, and the calculation formula of the PI coefficient optimization value is: wherein, PI coefficient optimization value of the next grinding process of the last grinding process in all grinding processes; vibration-grinding accuracy correlation of the last grinding process in all grinding processes; value of the PI coefficient of the last grinding process in all grinding processes; PI coefficient reference value of the next grinding process of the last grinding process in all grinding processes; PI coefficient parameter of the last grinding process in all grinding processes.

[0051] The PI coefficient optimization value of the next grinding process of the last grinding process in all grinding processes is used as the value of the PI coefficient of the PID control algorithm of the grinding process, and the grinding parameters of the planetary reducer gear shaft processing are adjusted using the PID control algorithm.

[0052] wherein, the grinding parameters are spindle speed or feed speed.

[0053] At this point, the processing of the planetary reducer gear shaft is completed, and the processing error is reduced during the processing.

[0054] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for machining planetary reducer gear shafts to reduce machining errors, characterized in that, The method includes the following steps: Set the initial value of the PI coefficient of the PID control algorithm, use the PID control algorithm to adjust the grinding parameters of the grinding process, and continuously collect the surface roughness of the first preset number of planetary reducer gear shafts before and after the grinding process, as well as the vibration value of the grinding process. Based on the difference in surface roughness before and after the same grinding process, the grinding effect of the same grinding process is determined. Based on the difference in the grinding effect of the first preset number of consecutive grinding processes and the difference in surface roughness, the stability of the processing effect of the last grinding process in all grinding processes and the predicted value of the surface roughness after the next grinding process of the last grinding process in all grinding processes are determined. Based on the surface roughness before and after the first preset number of grinding processes, the grinding effect, the stability of the grinding effect, the vibration value, the value of the PI coefficient during the grinding process, and the predicted value of the surface roughness after the next grinding process, the reference value of the PI coefficient for the next grinding process after the last grinding process in all grinding processes is determined, as well as the vibration-grinding accuracy correlation and PI coefficient parameters for the last grinding process in all grinding processes. Based on the reference value of the PI coefficient for grinding, the value of the PI coefficient, the correlation between vibration and grinding accuracy, and the PI coefficient parameters, the optimized value of the PI coefficient for the next grinding process is determined, and the planetary reducer gear shaft is machined according to the optimized PI coefficient value.

2. The method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The vibration value of the grinding process is specifically: The average value of all vibration data from the same grinding process is recorded as the vibration value of the grinding process.

3. The method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The specific method for determining the grinding effect of the aforementioned grinding process is as follows: The absolute value of the difference in surface roughness before and after the same grinding process is denoted as the roughness difference of the same grinding process, and the ratio of the roughness difference of the same grinding process to the surface roughness after the process is denoted as the grinding effect of the same grinding process.

4. The method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The specific method for determining the stability of the processing effect of the grinding process is as follows: The variance of the grinding effect of the first preset number of planetary reducer gear shafts in the grinding process is denoted as the first variance of the last grinding process in all grinding processes. The variance of the surface roughness of a first preset number of planetary reducer gear shafts after grinding is denoted as the second variance of the last grinding process in all grinding processes. The positive correlation between the first and second variances of the grinding process is recorded as the stability of the processing effect of the last grinding process among all grinding processes.

5. A method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The specific method for determining the predicted surface roughness value after the next grinding process following the last grinding process in all grinding processes is as follows: Based on the surface roughness of the first preset number of planetary reducer gear shafts after grinding, a predicted value for the surface roughness after the next grinding process is obtained.

6. A method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The method for obtaining the PI coefficient reference value is as follows: Based on the surface roughness before and after grinding, the grinding effect and the stability of the grinding effect, and the predicted value of the surface roughness after the next grinding, the first preset number of grinding processes are clustered to obtain the first grinding cluster. The average value of the PI coefficient during all grinding processes within the first grinding cluster where the last grinding process is located is recorded as the reference value of the PI coefficient for the next grinding process after the last grinding process.

7. The method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The specific calculation method for the vibration-grinding accuracy correlation is as follows: Based on the surface roughness before and after grinding, the vibration value of grinding, and the value of the PI coefficient during grinding, the first preset number of grinding processes are clustered to obtain the second grinding cluster. A vibration value sequence is constructed based on the vibration values ​​of all grinding processes within the second cluster of grinding processes where the last grinding process is located. Based on the surface roughness of all grinding processes within the second grinding cluster where the last grinding process is located, a post-processing surface roughness sequence is constructed. The absolute value of the correlation coefficient between the vibration value sequence and the post-processing surface roughness sequence is denoted as the vibration-grinding accuracy correlation of the last grinding process in all grinding processes.

8. A method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The specific method for determining the PI coefficient parameter is as follows: Based on the surface roughness before different grinding processes, the vibration values ​​of the first preset number of grinding processes are clustered to obtain the third grinding cluster; The average vibration value of all grinding processes contained in the third grinding cluster is denoted as the average vibration value of the third grinding cluster. Based on the vibration mean of all grinding third clusters, a vibration threshold is determined. The average value of the PI coefficient of the grinding processes included in all grinding third clusters with a vibration mean less than the vibration threshold is recorded as the PI coefficient parameter of the last grinding process among all grinding processes.

9. A method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The formula for calculating the optimized value of the PI coefficient is: in, This represents the optimized PI coefficient value for the next grinding process following the last grinding process in all grinding processes. This indicates the vibration-grinding accuracy correlation of the last grinding process in all grinding processes; This represents the value of the PI coefficient for the last grinding process out of all grinding processes. This represents the PI coefficient reference value for the next grinding process following the last grinding process in all grinding processes; This represents the PI coefficient parameter of the last grinding process in all grinding processes.

10. A method for machining planetary reducer gear shafts to reduce machining errors according to claim 1, characterized in that, The specific method for machining the planetary reducer gear shaft based on the PI coefficient optimization value includes: The optimized PI coefficient value of the next grinding process after the last grinding process in all grinding processes is used as the PI coefficient value of the PID control algorithm for this grinding process. The grinding parameters of the planetary reducer gear shaft machining are adjusted using the PID control algorithm.

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