Method and system for automatically regulating and controlling eccentric wire wrapping head tension

Abstract

The invention belongs to the technical field of eccentric wire wrapping head tension control, and discloses an eccentric wire wrapping head tension automatic regulation and control method and system. The method comprises the following steps: acquiring tension and core speed of wrapping materials on an eccentric side and a non-eccentric side, loads and rotating speeds of a servo motor and a variable frequency motor, power supply voltage of the variable frequency motor and feedback delay time of a servo motor encoder in real time; inputting the power supply voltage, the load and the rotating speed of the variable frequency motor in unit time into a pre-trained rotating speed prediction model, outputting to obtain a rotating speed deviation estimated value of the variable frequency motor at the next moment, and calculating to obtain a wire core speed estimated value in combination with the historical wire core speed and the transmission ratio in a set time window; according to the utility model, stable regulation and control of tension in the eccentric wire wrapping process are realized, balanced stress of a wrapping material is ensured, breakage, looseness or accumulation of the wrapping material is avoided, and the product quality and the production efficiency are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of eccentric wire package head tension control, and more particularly, to an eccentric wire package head tension automatic regulation method and system. BACKGROUND

[0002] In the eccentric wire winding process of electromagnetic wire production, tension regulation is the key to determining product quality. The core is to monitor the force difference of the winding material on the eccentric side and the non-eccentric side in real time through the tension sensor, and to dynamically adjust the material supply force on both sides by driving the hysteresis brake motor, tension lever and other actuators with the help of the control system, so as to balance the uneven stress caused by the eccentric structure and ensure that the winding layer on the eccentric side is tight and the non-eccentric side does not appear loose. Compared with ordinary concentric winding, in the eccentric wire winding, the coverage thickness of the winding material in the eccentric direction is larger, and the supply amount and stress state of the materials on both sides are naturally different, which makes the tension regulation system more sensitive to various interference factors, and the stability of the wire core running state is a key problem that can easily cause regulation failure.

[0003] Specifically, the stable operation of the tension regulation system depends on the dynamic matching of the winding material supply speed and the wire core speed, and the wire core speed is driven by two types of motors: the wire core main transmission system uses a variable frequency motor, which adjusts the power supply frequency through a frequency converter to realize large-scale continuous speed adjustment, to adapt to the production needs of different specifications of electromagnetic wire; the tension adjustment components of the winding mechanism are equipped with servo motors, which use encoders to feedback position information in real time to realize millisecond-level fine speed correction and ensure the precise synchronization of winding material supply and wire core running. However, the characteristic defects of the two types of motors will cause abnormal fluctuations in the wire core speed: the servo motor is prone to speed jump when the load suddenly changes due to the feedback delay of the encoder; the variable frequency motor is significantly affected by power supply voltage fluctuations, and unstable power supply will cause periodic speed fluctuations. Both of these fluctuations will cause the actual wire core speed to deviate from the expected value, directly breaking the balance of tension regulation.

[0004] At this time, the response lag problem of the tension control system is magnified: when the core speed suddenly increases, the tension on the eccentric side increases more obviously due to the greater demand for wrapping material, which easily causes the wrapping material to be excessively pulled; when the core speed suddenly decreases, more excess wrapping material accumulates on the eccentric side, and the tension decreases more greatly, and the non-eccentric side may also be loose due to excess supply. This tension imbalance caused by abnormal core speed makes the already complex eccentric wire tension control repeatedly fall into a chaotic state, making it difficult to maintain the stability of the wrapping layers on both sides. The failure of tension control is particularly harmful to eccentric wire wrapping: sudden tension increase on the eccentric side can cause the wrapping material such as glass fiber and film to break, or make the insulation layer on that side too thin due to excessive stretching, affecting the voltage resistance performance of the magnet wire; sudden tension decrease on the non-eccentric side can cause the wrapping material to relax and wrinkle, forming a local insulation weak point. At the same time, the sharp fluctuation of tension will react on the core, causing irregular elastic deformation of the core, further exacerbating speed instability, forming a vicious cycle of tension imbalance and speed fluctuation, ultimately leading to problems such as uneven insulation layer thickness and eccentricity deviation in the eccentric wire wrapped magnet wire, significantly reducing product qualification rate and severely restricting production efficiency

[0005] In the production of magnet wires, the failure of such tension control is particularly harmful to eccentric wire wrapping: sudden tension increase on the eccentric side can cause the wrapping material such as glass fiber and film to break, or make the insulation layer on that side too thin due to excessive stretching, affecting the voltage resistance performance of the magnet wire; sudden tension decrease on the non-eccentric side can cause the wrapping material to relax and wrinkle, forming a local insulation weak point. At the same time, the sharp fluctuation of tension will react on the core, causing irregular elastic deformation of the core, further exacerbating speed instability, forming a vicious cycle of tension imbalance and speed fluctuation, ultimately leading to problems such as uneven insulation layer thickness and eccentricity deviation in the eccentric wire wrapped magnet wire, significantly reducing product qualification rate and severely restricting production efficiency.

[0006] In view of this, the present application proposes an automatic tension control method and system for eccentric wire head wrapping to solve the above problems. SUMMARY

[0007] In order to overcome the above-mentioned defects of the prior art and achieve the above-mentioned purposes, the present application provides the following technical solutions: an automatic tension control method for eccentric wire head wrapping, comprising:

[0008] real-time acquisition of the tension of the wrapping material on the eccentric side and the non-eccentric side, the core speed, the load and speed of the servo motor and the frequency conversion motor, the power supply voltage of the frequency conversion motor, and the feedback delay time of the servo motor encoder; the servo motor is used to adjust the tension of the wrapping material; the frequency conversion motor is used to adjust the core speed;

[0009] The power supply voltage, load and rotating speed of the variable frequency motor per unit time are input into the pre-trained rotating speed prediction model, and a rotating speed deviation estimation value of the variable frequency motor at the next moment is output, and the historical linear core speed and transmission ratio in the set time window are combined to calculate a linear core speed estimation value; the transmission ratio is a conversion coefficient between the rotating speed of the variable frequency motor and the linear core speed;

[0010] Based on the linear core speed estimation value, the current linear core speed and the rotating speed of the current variable frequency motor, the power supply frequency of the frequency converter of the variable frequency motor is adjusted; based on the feedback delay time of the servo motor encoder and the current rotating speed of the servo motor, the rotating speed of the servo motor at the next moment is adjusted;

[0011] Based on the linear core speed estimation value, the current linear core speed, and the tension of the eccentric side and the non-eccentric side of the wrapped material, the rotating speeds of the servo motor and the variable frequency motor at the next moment are adjusted.

[0012] Further, the method for adjusting the power supply frequency of the frequency converter of the variable frequency motor based on the linear core speed estimation value and the linear core speed at the corresponding moment, and the rotating speed of the variable frequency motor comprises:

[0013] The difference between the linear core speed estimation value and the current linear core speed is calculated to obtain a linear core speed deviation;

[0014] The difference between the rotating speed of the current variable frequency motor and the set rotating speed of the variable frequency motor is calculated to obtain a variable frequency motor rotating speed fluctuation;

[0015] The difference between the rotating speed of the current servo motor and the set rotating speed of the servo motor is calculated to obtain a servo motor rotating speed fluctuation;

[0016] The weighted sum of the absolute value of the linear core speed deviation and the absolute value of the variable frequency motor rotating speed fluctuation is calculated to obtain a compensation frequency;

[0017] When the absolute value of the linear core speed deviation is greater than the set speed deviation threshold, based on the linear core speed deviation and the positive and negative of the variable frequency motor rotating speed fluctuation, the corresponding power supply frequency is output from the frequency converter to the variable frequency motor.

[0018] Further, the method for outputting the corresponding power supply frequency from the frequency converter to the variable frequency motor based on the linear core speed deviation and the positive and negative of the variable frequency motor rotating speed fluctuation comprises:

[0019] If the linear core speed deviation is positive and the variable frequency motor rotating speed fluctuation is negative, the sum of the current power supply frequency and the compensation frequency is output from the frequency converter to the variable frequency motor;

[0020] If the linear core speed deviation is negative and the variable frequency motor rotating speed fluctuation is positive, the difference between the current power supply frequency and the compensation frequency is output from the frequency converter to the variable frequency motor.

[0021] Furthermore, the method for adjusting the servo motor speed at the next moment based on the feedback delay time of the servo motor encoder and the current servo motor speed includes:

[0022] Based on the current servo motor speed, the previous speed, and the feedback delay time of the servo motor encoder, the speed lag is obtained.

[0023] The corrected speed is obtained by adding the speed lag to the current speed of the servo motor.

[0024] If the speed lag is not zero, a corrected speed is output to the servo motor.

[0025] Furthermore, based on the estimated core speed, the current core speed, and the tension of the wrapping material on both the eccentric and non-eccentric sides, the methods for adjusting the speeds of the servo motor and the variable frequency motor at the next moment include:

[0026] The tension difference is obtained by calculating the tension difference between the wrapping materials on the eccentric side and the non-eccentric side;

[0027] Based on the material of the wrapping material, a safe range for tension difference is pre-set;

[0028] If the tension difference exceeds the safe range, the speed of the servo motor and the variable frequency motor will be adjusted at the next moment based on the deviation of the wire core speed and the sign of the tension difference.

[0029] Furthermore, based on the sign of the wire core speed deviation and tension difference, the methods for adjusting the speeds of the servo motor and the frequency converter at the next moment include:

[0030] Calculate the speed correction amount based on the core speed deviation, the current tension difference, and the current load of the servo motor and the variable frequency motor;

[0031] If the core speed deviation is positive and the tension difference is positive, then the speed of the eccentric side servo motor will be corrected to the sum of the current speed and the speed correction amount. If the speed of the variable frequency motor is less than the set speed of the variable frequency motor, then the speed of the variable frequency motor will be corrected to the sum of the current speed and the speed correction amount.

[0032] If the core speed deviation is positive and the tension difference is negative, the speed of the non-eccentric servo motor will be corrected to the difference between the current speed and the speed correction amount. If the load of the variable frequency motor is greater than the rated load of the preset ratio, the speed of the variable frequency motor will be corrected to the difference between the current speed and the speed correction amount.

[0033] If the core speed deviation is negative and the tension difference is negative, the speed of the eccentric servo motor will be corrected to the difference between the current speed and the speed correction amount. If the speed of the variable frequency motor is less than the speed of the variable frequency motor set by the preset ratio, the speed of the variable frequency motor will be corrected to the sum of the current speed and the speed correction amount.

[0034] If the core speed deviation is negative and the tension difference is positive, the speed of the non- eccentric side servo motor is corrected to the difference between the current speed and the speed correction amount, and if the load of the variable frequency motor is less than the preset proportion of the rated load, the speed of the variable frequency motor is corrected to the difference between the current speed and the speed correction amount.

[0035] Further, based on the core speed deviation, the current tension difference, and the current loads of the servo motor and the variable frequency motor, the method for calculating the speed correction amount comprises:

[0036] The speed influence coefficient, the tension influence coefficient, and the load influence coefficient are fitted by the core speed deviation, the tension difference, and the load in the historical data, and the corresponding speed correction amount;

[0037] The speed influence coefficient is the speed correction amount corresponding to each unit of the core speed deviation; the tension influence coefficient is the speed correction amount corresponding to each unit of the tension difference; and the load influence coefficient is the speed correction amount corresponding to each unit of the load;

[0038] Speed correction amount = speed influence coefficient × absolute value of core speed deviation + tension influence coefficient × absolute value of current tension difference + load influence coefficient × current load.

[0039] Further, the training method of the speed prediction model comprises:

[0040] The historical power supply voltage, the historical load, and the historical speed of the variable frequency motor are collected to form a training set;

[0041] The training set is preprocessed by removing outliers, and the power supply voltage, the load, and the speed of the variable frequency motor at consecutive multiple time points are taken as input samples in time sequence, and the speed deviation prediction value at the corresponding time point is taken as an output label to obtain preprocessed data;

[0042] A time series network architecture is built based on LSTM, and corresponding hidden layers, neurons, and activation functions are set to obtain an initial model;

[0043] The preprocessed data is divided into a training set, a test set, and a validation set in proportion, the initial model is trained by a back propagation algorithm and the validation set error is monitored in real time, and the training is stopped when the error no longer decreases;

[0044] The performance of the initial model is evaluated with the test set, the initial model parameters are adjusted for retraining if the prediction error exceeds the set range, until the preset accuracy requirement is met, and a trained speed prediction model is obtained.

[0045] Further, based on the speed deviation prediction value, the historical core speed and the transmission ratio in a time window are set to calculate the core speed prediction value.

[0046] The pre-trained rotating speed prediction model is used to output a rotating speed deviation estimation value of the variable frequency motor, and the rotating speed deviation estimation value of the variable frequency motor is a difference between the estimated rotating speed and the set rotating speed.

[0047] The mean value of the historical core speed in the set time window is calculated as a historical reference value of the core speed.

[0048] The rotating speed deviation estimation value is multiplied by the transmission ratio to obtain a core speed deviation estimation value.

[0049] The historical reference value of the core speed is added to the core speed deviation estimation value to obtain a core speed estimation value.

[0050] The data acquisition module is used to acquire the tension of the eccentric side and the non-eccentric side, the core speed, the load and the rotating speed of the servo motor and the variable frequency motor, the power supply voltage of the variable frequency motor, and the feedback delay time of the servo motor encoder in real time.

[0051] The rotating speed prediction module is used to input the power supply voltage, the load and the rotating speed of the variable frequency motor in a unit time into the pre-trained rotating speed prediction model, output a rotating speed deviation estimation value of the variable frequency motor at the next moment, and calculate a core speed estimation value in combination with the historical core speed in the set time window and the transmission ratio.

[0052] The motor adjustment module is used to adjust the power supply frequency of the frequency converter of the variable frequency motor based on the core speed estimation value, the current core speed and the rotating speed of the current variable frequency motor, and adjust the rotating speed of the servo motor at the next moment based on the feedback delay time of the servo motor encoder and the current rotating speed of the servo motor.

[0053] The rotating speed adjustment module is used to adjust the rotating speed of the servo motor and the variable frequency motor at the next moment based on the core speed estimation value, the current core speed and the tension of the eccentric side and the non-eccentric side.

[0054] Compared with the prior art, the technical effects and advantages of the eccentric wire package head tension automatic regulation method and system are as follows:

[0055] The present application acquires the tension of the eccentric side and the non-eccentric side, the core speed, the load and the rotating speed of the servo motor and the variable frequency motor, the power supply voltage of the variable frequency motor, and the feedback delay time of the servo motor encoder in real time, uses the pre-trained LSTM model to predict the rotating speed deviation at the next moment based on the power supply voltage, the load and the rotating speed of the variable frequency motor, calculates the core speed estimation value in combination with the historical core speed and the transmission ratio, adjusts the power supply frequency of the frequency converter based on the core speed estimation value, the current core speed and the rotating speed of the variable frequency motor, adjusts the rotating speed of the servo motor according to the feedback delay time of the servo motor encoder and the rotating speed, and dynamically adjusts the rotating speed of the servo motor and the variable frequency motor in combination with the tension difference between the eccentric side and the non-eccentric side and the safety interval according to the positive and negative situations of the core speed deviation and the tension difference.

[0056] This invention solves the problems of speed jumps in servo motors due to encoder feedback delay during sudden load changes and periodic speed fluctuations in variable frequency motors caused by power supply voltage fluctuations. It achieves stable tension control during the eccentric wire winding process, ensuring balanced force on the winding material, avoiding breakage, loosening or accumulation of the winding material, and improving product quality and production efficiency. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of an automatic tension control system for eccentric yarn wrapping according to an embodiment of the present invention;

[0058] Figure 2 This is a flowchart of an automatic tension control method for eccentric yarn wrapping according to an embodiment of the present invention;

[0059] Figure 3 This is a flowchart illustrating a method for outputting a corresponding power supply frequency from a frequency converter to a frequency converter based on the positive and negative values ​​of the wire core speed deviation and the speed fluctuation of the frequency converter motor, according to an embodiment of the present invention.

[0060] Figure 4 This is a flowchart illustrating a method for adjusting the speeds of the servo motor and the variable frequency motor at the next moment based on the positive and negative values ​​of the wire core speed deviation and tension difference, according to an embodiment of the present invention.

[0061] Figure 5 This is a schematic diagram of the training method for the speed prediction model according to an embodiment of the present invention. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be described in detail, clearly, and completely below with reference to the accompanying drawings. It should be particularly noted that the specific embodiments described below are only used to better illustrate and explain the technical solutions of the present invention, and are intended to enable those skilled in the art to better understand and implement the present invention, and should not be construed as limiting the scope of protection of the present invention. Without departing from the spirit and substance of the present invention, those skilled in the art can modify, adjust, or make equivalent substitutions based on the content disclosed in the present invention, and these should all be considered within the scope of protection of the present invention.

[0063] Example 1

[0064] Please see Figure 1 As shown, this embodiment discloses an automatic tension control system for eccentric yarn wrapping, including modules that are connected by wires and / or wirelessly to achieve data transmission.

[0065] The data acquisition module is used to acquire in real time the tension of the wrapping material on the eccentric and non-eccentric sides, the core speed, the load and speed of the servo motor and the variable frequency motor, the power supply voltage of the variable frequency motor, and the feedback delay time of the servo motor encoder.

[0066] The tension of the eccentric side and the non-eccentric side around the wrapping material needs to be installed with a tension sensor, such as a strain gauge type tension sensor, in the running path of the wrapping material on both sides. The tension sensor is connected in series between the wrapping material and the guide wheel to ensure that the tension of the wrapping material directly acts on the sensing end of the tension sensor. The collection of the linear core speed needs to install an incremental encoder on the driven wheel of the linear core traction mechanism. The incremental encoder is coaxially connected with the driven wheel. When the linear core drives the driven wheel to rotate, the incremental encoder outputs a pulse signal. The real-time linear core speed is calculated according to the pulse frequency and the circumference of the driven wheel. The speed of the servo motor is obtained through the absolute value encoder attached to it. The absolute value encoder outputs the angular position pulse of the motor shaft in real time. The speed is obtained by calculating the number of angular position pulses per unit time. The load of the servo motor is obtained through the servo driver. The driver monitors the winding current of the servo motor and calculates the load percentage in combination with the rated current of the servo motor, i.e. load = real-time current / rated current x 100%. The speed of the variable frequency motor is detected in real time by the frequency converter. The frequency converter calculates the speed by the power supply frequency and the pole pair number of the variable frequency motor, i.e. speed = 60 x power supply frequency / pole pair number. At the same time, the load percentage is converted by detecting the motor input current and referring to the rated current. The power supply voltage of the variable frequency motor needs to be obtained by connecting a voltage sensor, such as a Hall voltage sensor, in parallel on its power supply line. The feedback delay time of the servo motor encoder is measured by a timer. The time when the speed command is sent and the time when the encoder feedback signal is received are recorded. The time difference between the two is the feedback delay time.

[0067] Real-time acquisition of the tension of the eccentric side and the non-eccentric side wrapping material can directly monitor whether the force difference of the wrapping material on both sides is in a balanced state. The eccentric structure naturally causes the force difference of the material on both sides, and sudden increase or decrease of the tension is a direct manifestation of the imbalance of the tension. Real-time tension data can capture this abnormality in the first time, providing original basis for judging whether the tension exceeds the safety range and whether the motor action needs to be adjusted, avoiding excessive pulling of the eccentric side wrapping material or accumulation of the non-eccentric side wrapping material due to too large force difference.

[0068] Real-time data of the linear core speed is the core reference for tracking speed fluctuation. Dynamic matching of the linear core speed and the wrapping material supply speed is the premise of tension stability, and abnormal fluctuation of the linear core speed is a direct cause of tension imbalance. Real-time acquisition of the linear core speed can find that it deviates from the expected value in time, providing monitoring basis for subsequent adjustment of the speed of the variable frequency motor and the servo motor to stabilize the linear core speed, preventing the speed from being abnormally detected in time and amplifying the tension fluctuation, such as sudden increase of the speed leading to sudden increase of the tension of the eccentric side wrapping material.

[0069] The load and speed data of the servo motor, combined with the feedback delay time of the servo motor encoder, can solve the problem of speed jump of the servo motor caused by encoder feedback delay when the load changes. The sudden change of the actual speed of the servo motor will cause the system to adjust based on the old data, resulting in the disconnection of the command and the actual demand. By monitoring the load and speed of the servo motor in real time, and combining the delay time to calculate the speed lag, the speed command can be corrected in advance, so that the speed of the servo motor is accurately synchronized with the movement of the wire core, reducing the interference of speed jump on the speed of the wire core, and avoiding the breaking of tension balance caused by jump.

[0070] The load, speed and power supply voltage data of the variable frequency motor are the key to solving the problem of periodic speed jitter of the variable frequency motor caused by power supply voltage fluctuation. The power supply voltage directly reflects the power grid fluctuation, while the load and speed data record the response law of the variable frequency motor under dynamic disturbance, such as the correlation between load increase and speed drop when voltage decreases.

[0071] The feedback delay time of the servo motor encoder is used to quantify the influence of delay on the regulation of the servo motor. The encoder delay will cause the system to collect historical data of the speed, and the adjustment command will be disconnected from the actual demand when the load changes, causing speed jump. After obtaining the delay time in real time, the speed lag can be calculated to correct the speed command of the servo motor, so that the adjustment action is synchronized with the actual state of the motor, avoiding the speed jump caused by delay, and ensuring the accurate matching of the supply speed of the wrapping material and the speed of the wire core.

[0072] The speed prediction module is used to input the power supply voltage, load and speed of the variable frequency motor per unit time into the pre-trained speed prediction model, output the estimated value of the speed deviation of the variable frequency motor at the future time, and calculate the estimated value of the wire core speed by combining the historical wire core speed and transmission ratio in the set time window. The transmission ratio is the conversion coefficient between the speed of the variable frequency motor and the speed of the wire core.

[0073] In actual production, the estimated value of the wire core speed cannot be achieved by direct presetting, the power supply voltage fluctuation of the variable frequency motor will change the output torque of the variable frequency motor, the load change such as uneven material of the wire core and sudden change of the wrapping tension will cause nonlinear response of the speed of the variable frequency motor, and even the mechanical gap of the transmission mechanism will also cause slight fluctuation of the wire core speed. The power supply voltage, load and speed data of the variable frequency motor have randomness and real-time nature. If the fixed estimated value of the wire core speed is directly preset, there will be a continuous deviation from the actual wire core speed. When the actual wire core speed is higher than the preset wire core speed, the wrapping tension will suddenly increase, causing the wire core to be pulled tight; when the actual wire core speed is lower than the preset wire core speed, the tension will relax, causing the wire core to sag, ultimately leading to uneven wire diameter or broken wire and other wrapping quality defects. Therefore, the real-time trend of the wire core speed must be captured through dynamic prediction, rather than relying on presetting.

[0074] At the same time, the change of the linear core speed will directly lead to the change of the tension of the wrapping material, and the tension will increase when the linear core speed increases, and the tension will decrease when the linear core speed decreases. However, there is a physical delay in motor control, such as the response time of the frequency converter or mechanical inertia when adjusting the speed of the frequency conversion motor. Through the linear core speed prediction value, the future trend of the linear core speed can be judged in advance: if it is predicted that the speed will decrease soon, the speed of the frequency conversion motor can be increased in advance to offset the speed decrease; if it is predicted that the speed will increase soon, the speed of the frequency conversion motor can be reduced in advance to suppress the sudden change of the tension.

[0075] In addition, the linear core is connected to the frequency conversion motor through a transmission mechanism such as a gear or a roller. When the transmission ratio is fixed, the linear core speed is proportional to the speed of the frequency conversion motor, i.e. linear core speed = frequency conversion motor speed x transmission ratio. Therefore, the motor speed itself is a direct mapping of the linear core speed. The supply voltage and the load are the key variables that affect the motor speed. Voltage fluctuations will change the output torque of the frequency conversion motor. When the supply voltage decreases, the torque is insufficient, and the speed is easy to decrease. An increase in load will force the frequency conversion motor to reduce speed. The voltage, load, and speed data in a unit of time record the response law of the motor under dynamic interference. By training the speed prediction model, such as the LSTM neural network, the time correlation law of voltage-load-speed change and linear core speed change in historical data can be learned. Based on the real-time data in the current unit of time, the trend of the linear core speed in the future, such as 1-3 seconds, can be deduced, and finally the linear core speed prediction value is obtained.

[0076] Based on the speed deviation prediction value, the historical linear core speed and the transmission ratio in a set time window are calculated to obtain the linear core speed prediction value, as follows:

[0077] The pre-trained speed prediction model outputs the speed deviation prediction value of the frequency conversion motor. The average value of the historical linear core speed in the set time window is calculated as the historical reference value of the linear core speed. The speed deviation prediction value is multiplied by the transmission ratio to obtain the linear core speed deviation prediction value. The historical reference value of the linear core speed is added to the linear core speed deviation prediction value to obtain the linear core speed prediction value.

[0078] wherein the time window is set to match the fluctuation frequency of the wire core speed. If the wire core speed fluctuates at a high frequency and small amplitude due to material tension changes, motor load fluctuations, and other process characteristics, for example, more than 10 times per second, the time window should be selected to be small, for example, 0.1-0.5 seconds, to avoid including too much outdated data, causing the mean to lag behind the actual changes. If the speed changes smoothly, for example, several times per minute, the window can be appropriately increased, for example, 1-3 seconds, to smooth out random noise through more historical data, ensuring the stability of the historical reference value. In addition, the time scale of the pre-trained speed prediction model also needs to be adapted. The pre-trained speed prediction model is trained based on samples of a specific time interval, for example, data is collected every 0.01 seconds. The selection of the time window needs to match the input time step of the speed prediction model, for example, the model input is the data of the past 10 time steps, then the window can be set to 0.01 seconds x 10 = 0.1 seconds, to ensure the consistency of the speed deviation prediction value and the historical reference value of the wire core speed in the time dimension, avoiding the increase of prediction error due to the mismatch of time scale.

[0079] Referring to Figure 5 As shown in the figure, the training method of the speed prediction model is as follows:

[0080] Collect the historical supply voltage, historical load and historical speed of the variable frequency motor to form a training set; perform outlier rejection preprocessing on the training set, and take the supply voltage, load and speed of the variable frequency motor at consecutive multiple time points as input samples according to the time sequence, and take the speed deviation prediction value at the corresponding time as the output label to obtain the preprocessed data; build a time series network architecture based on LSTM, and set the corresponding hidden layer, neuron and activation function to obtain an initial model, for example, 2 layers of hidden layers can be set, the first layer contains 128 LSTM neurons to capture the long-period correlation between the supply voltage, load and speed of the variable frequency motor, and the second layer contains 64 LSTM neurons to extract short-term dynamic characteristics, both layers use tanh activation function to adapt to the numerical range of the LSTM internal control mechanism, the output layer is set to 1 neuron and uses linear activation function because the speed deviation prediction value is a continuous value and does not need nonlinear mapping, and a dropout layer is added between the two hidden layers to prevent overfitting; the preprocessed data is divided into training set, test set and validation set in proportion, the initial model is trained through the back propagation algorithm and the validation set error is monitored in real time, and the training is stopped when the error no longer decreases; the performance of the initial model is evaluated using the test set, if the prediction error exceeds the set range, the initial model parameters are adjusted and retrained until the preset accuracy requirement is met, to obtain the trained speed prediction model, for example, the mean square error (MSE) of the predicted speed deviation prediction value and the actual speed deviation on the test set can be calculated to evaluate the performance, if the set accuracy requirement is MSE≤0.5 rpm 2 , and the initial model after the first training has a MSE of 0.8 rpm 2Then the initial model parameters need to be adjusted: increase the number of first layer neurons to 150 to enhance feature extraction capability, reduce the learning rate from 0.001 to 0.0005 to avoid training shock, and increase the training rounds to 200 rounds. After retraining, if the test set MSE is reduced to 0.3 rpm 2 Then the trained speed prediction model is obtained.

[0081] The motor adjustment module adjusts the power supply frequency of the frequency converter of the variable frequency motor based on the wire core speed estimate, the current wire core speed, and the current variable frequency motor speed. Based on the feedback delay time of the servo motor encoder and the current servo motor speed, the speed of the servo motor at the next time is adjusted.

[0082] Based on the wire core speed estimate and the wire core speed at the corresponding time, and the speed of the variable frequency motor, the power supply frequency of the frequency converter of the variable frequency motor is adjusted, specifically as follows:

[0083] The difference between the wire core speed estimate and the current wire core speed is calculated to obtain the wire core speed deviation. The difference between the current variable frequency motor speed and the set variable frequency motor speed is calculated to obtain the variable frequency motor speed fluctuation. The set variable frequency motor speed is determined according to the production of the magnet wire specification. Different specifications of magnet wire correspond to different wire core target running speeds. The wire core speed and the variable frequency motor speed are related through a fixed transmission ratio. Therefore, the wire core target speed and the transmission ratio need to be calculated to adapt to the wide range of speed adjustment requirements of the wire core main drive system, and to ensure that the wire core can run stably at the basic speed required by the process. The difference between the current servo motor speed and the set servo motor speed is calculated to obtain the servo motor speed fluctuation. The set servo motor speed is determined according to the type of wrapping material and the wrapping density requirement. It needs to match the wire core speed to ensure the precise synchronization of the wrapping material supply speed and the wire core speed, thereby maintaining the basic tension balance of the wrapping material and avoiding abnormal tension caused by mismatch between the supply and the wire core speed. The value needs to be combined with the breaking tension and elongation of the wrapping material to ensure that the wrapping material will not be excessively stretched due to slow supply, nor will it accumulate due to fast supply. The weighted sum of the absolute value of the wire core speed deviation and the absolute value of the variable frequency motor speed fluctuation is calculated to obtain the compensation frequency.

[0084] The weights of the absolute value of the wire core speed deviation and the absolute value of the variable frequency motor speed fluctuation are obtained by collecting the corresponding relationship between the wire core speed deviation, the variable frequency motor speed fluctuation, and the actual required frequency adjustment under different working conditions. For example, when the wire core speed deviation is 0.2 m / s, an adjustment of 0.004 Hz is required to offset the speed deviation. When the variable frequency motor speed fluctuation is 5 rpm, an adjustment of 0.05 Hz is required to stabilize the speed. The contribution weights of the wire core speed deviation and the variable frequency motor speed fluctuation to the frequency compensation are fitted by the least squares method.

[0085] Please refer to Figure 3 When the absolute value of the core speed deviation is greater than the set speed deviation threshold, the corresponding power supply frequency is output from the frequency converter to the variable frequency motor based on the core speed deviation and the positive or negative of the variable frequency motor speed fluctuation amount, as follows:

[0086] The speed deviation threshold is determined in combination with the stress characteristics of the wrapping material and the production process requirements. First, referring to the elongation and breaking tension of the wrapping material, the speed fluctuation range that the material can withstand directly determines the upper limit of the speed deviation threshold, avoiding excessive stretching or accumulation of the wrapping material due to excessive deviation. At the same time, according to the production of the magnet wire specifications, different specifications correspond to different core speeds, and the speed deviation threshold needs to be adapted to the core speed. The speed deviation threshold can be appropriately relaxed when the core speed is high, and it needs to be tightened to ensure accuracy when it is low. When setting, test production is tested, and the deviation value is gradually adjusted. Whether the core speed under this deviation will cause the tension difference to exceed the safe interval is observed, and the maximum deviation that does not cause tension imbalance is taken as the speed deviation threshold, while considering the adjustment stability, avoiding the fluctuation caused by frequent adjustment of the variable frequency motor due to too small speed deviation threshold, or the adjustment lag caused by too large speed deviation threshold.

[0087] If the core speed deviation is positive and the variable frequency motor speed fluctuation amount is negative, the sum of the current power supply frequency and the compensation frequency is output from the frequency converter to the variable frequency motor. Because when the core speed deviation is positive, that is, the core speed estimated value is higher than the current actual core speed, it indicates that the future core speed has a rising trend, and the variable frequency motor speed fluctuation amount is negative, that is, the current variable frequency motor actual speed is lower than the set speed. At this time, if there is no intervention, the core speed will be difficult to reach the estimated value due to insufficient motor power, forming a situation of insufficient speed. At this time, the command of the sum of the current power supply frequency and the compensation frequency is output to the frequency converter to directly increase the power supply frequency of the frequency converter. Since the speed of the variable frequency motor is positively correlated with the power supply frequency, the increase in the power supply frequency will immediately drive the motor speed to rise, and the motor speed directly acts on the core through the fixed transmission ratio, so that the core speed rises synchronously with the motor speed. The time of the advance adjustment matches the prediction period of the speed prediction model. When the future core speed rises according to the estimated value, the variable frequency motor has completed the speed reserve through the advance speed-up, thereby offsetting the speed deficiency that may be caused by the low speed of the variable frequency motor, and ensuring the smooth transition of the core speed to the estimated value.

[0088] If the core speed deviation is negative and the variable frequency motor speed fluctuation is positive, the difference between the current power supply frequency and the compensation frequency is output to the variable frequency motor. Because when the core speed deviation is negative, that is, the core speed estimate is lower than the current actual core speed, it indicates that the future core speed will decrease, and the variable frequency motor speed fluctuation is positive, that is, the current variable frequency motor actual speed is higher than the set speed, at this time if no intervention, the core speed will exceed the estimated value due to the excess power of the motor, forming the situation of too high speed, at this time the power supply frequency of the frequency converter needs to be reduced by outputting the command of the difference between the current power supply frequency and the compensation frequency to the frequency converter. The reduction of the power supply frequency will directly lead to the reduction of the motor speed, and the core speed will be reduced synchronously through the transmission ratio. When the future core speed decreases according to the estimated value, the motor has reduced the power output by reducing the speed in advance, avoiding the situation that the core speed exceeds the core speed estimate due to the too high speed, ensuring that the core speed fluctuates stably around the core speed estimate.

[0089] For the case that the core speed deviation is positive and the variable frequency motor speed fluctuation is positive, and the core speed deviation is negative and the variable frequency motor speed fluctuation is negative, no adjustment is needed because the physical meaning and adjustment target do not match, as follows:

[0090] The positive core speed deviation indicates that the core speed estimate is higher than the current actual core speed, if the variable frequency motor speed fluctuation is positive at this time, that is, the actual speed is higher than the set speed, it indicates that the current output of the variable frequency motor is too strong, the core speed will naturally rise in the future due to the too high speed, and there is no need to additionally increase the frequency, otherwise it will exacerbate the too high speed. The negative core speed deviation indicates that the core speed estimate is lower than the current actual core speed, if the variable frequency motor speed fluctuation is negative at this time, that is, the actual speed is lower than the set speed, it indicates that the current output of the variable frequency motor is too weak, the core speed will naturally decrease in the future due to the too low speed, and there is no need to additionally reduce the frequency, otherwise it will exacerbate the too low speed.

[0091] Based on the feedback delay time of the servo motor encoder and the current speed of the servo motor, the speed of the servo motor at the next time is adjusted, as follows:

[0092] Based on the current speed of the servo motor, the speed at the last time, and the feedback delay time of the servo motor encoder, the speed lag is obtained; the speed lag = (real-time speed of the servo motor - speed at the last unit time) x feedback delay time of the servo motor encoder.

[0093] The speed lag is added to the current speed of the servo motor to obtain the corrected speed; if the speed lag is not 0, the corrected speed is output to the servo motor.

[0094] The encoder feedback delay of the servo motor can cause the collected rotation speed of the servo motor to be not a real-time value, but historical data before the delay. When the load suddenly changes, the actual rotation speed of the servo motor has begun to change rapidly, but the system is still based on the old data to adjust, causing the adjustment instruction to be inconsistent with the actual demand. For example, when the load suddenly drops, the servo motor has accelerated, but the system is still outputting an instruction to maintain the original rotation speed, eventually causing the rotation speed of the servo motor to jump excessively.

[0095] The rotation speed hysteresis is calculated to quantify the influence of the encoder feedback delay of the servo motor. For example, if the encoder feedback delay time of the servo motor is 0.02 s, and the rotation speed of the servo motor increases from 1000 rpm to 1005 rpm within 0.001 s, the rotation speed hysteresis = 0.02*5000 = 100 rpm, which means that the system considers that the rotation speed of the servo motor is 1000 rpm, while the actual rotation speed is 1100 rpm, and there is a hysteresis deviation of 100 rpm.

[0096] The modified rotation speed is output based on the hysteresis, which essentially makes up for the rotation speed deviation in advance. When the rotation speed hysteresis is positive, that is, the actual rotation speed of the servo motor is higher than the system's perceived value due to the encoder feedback delay of the servo motor, the system outputs a higher rotation speed instruction in advance by outputting a modified rotation speed to the servo motor, to offset the insufficient rotation speed accumulated during the delay. When the rotation speed hysteresis is negative, that is, the actual rotation speed is lower than the system's perceived value due to the delay, the system reduces the rotation speed of the servo motor by outputting a modified rotation speed to the servo motor, to suppress the possible excessive decrease in rotation speed in advance. This advance correction is equivalent to completing the rotation speed adjustment of the servo motor within the encoder feedback delay time of the servo motor, so that the system is synchronized with the actual rotation speed of the servo motor, avoiding the excessive jump in the rotation speed of the servo motor caused by the encoder feedback delay of the servo motor.

[0097] The rotation speed adjustment module adjusts the rotation speed of the servo motor and the variable frequency motor at the next time based on the wire core speed estimation value, the current wire core speed, and the tension of the eccentric side and the non-eccentric side wrapping material.

[0098] The rotation speed of the servo motor and the variable frequency motor at the next time is adjusted based on the wire core speed estimation value, the current wire core speed, and the tension of the eccentric side and the non-eccentric side wrapping material, as follows:

[0099] The difference between the tensions of the eccentric side and the non-eccentric side wrapping material is calculated to obtain the tension difference.

[0100] According to the material of the wrapping material, the safety range of the tension difference is preset: the core physical parameters of the material of the wrapping material need to be collected, including the breaking tension, i.e. the maximum tension that the material can withstand, the elastic modulus, i.e. the tensile strength of the material, and the elongation, i.e. the maximum elongation ratio before the material breaks, which can be obtained from the factory specification or measured by material mechanics test. For example, the breaking tension of glass silk is usually 5-8N, and the breaking tension of film is 3-5N, and the elongation is lower than that of glass silk. Then start the eccentric silk wrapping device in the unloaded state, and pass the wrapping material to be set for the safety range of the tension difference into the wrapping mechanism of the eccentric side and the non-eccentric side respectively, and gradually adjust the initial tension of both sides to the basic value required by the process, for example, 3N on the eccentric side and 2N on the non-eccentric side, and then slowly change the tension of one side through the tension adjusting device, so that the tension difference gradually increases from 0, for example, it can be increased by 0.2N each time, while observing the state of the wrapping material in real time: if the wrapping material appears local tensile deformation, such as film wrinkles or glass silk micro-cracks, record the tension difference value at this time as the early warning threshold; if the wrapping material breaks or obviously relaxes, such as yarn disconnection, record the tension difference value at this time as the limit threshold. Then repeat the above test under the loaded production condition, because the friction force generated by the movement of the core will change the actual stress state of the material, the early warning threshold and the limit threshold need to be corrected in combination with the core speed, for example, when the core speed is increased by 10%, the early warning threshold of glass silk needs to be reduced by 0.3N to avoid brittle fracture at high speed. Finally, the range between the corrected early warning threshold and the limit threshold is determined as the safety range of the tension difference of the material, for example, glass silk is set to -0.5N to +0.8N, and film is set to -0.3N to +1.0N, where the negative sign indicates that the tension of the non-eccentric side is greater than that of the eccentric side.

[0101] Please refer to Figure 4 If the tension difference exceeds the safety range, the speed of the servo motor and the variable frequency motor at the next moment is adjusted based on the core speed deviation and the positive and negative of the tension difference, as follows:

[0102] Based on the core speed deviation, the current tension difference and the current servo motor and variable frequency motor load, the speed correction amount is calculated, specifically: through the historical data of the core speed deviation, the tension difference and the load, and the corresponding speed correction amount, the speed influence coefficient, the tension influence coefficient and the load influence coefficient are fitted, for example, 1000 groups of historical data in the same wrapping material production process in the past 3 months are selected, each group of data contains the core speed deviation (unit: m / s), the tension difference (unit: N), the variable frequency motor load (unit: % rated load) and the corresponding actual speed correction amount (unit: rpm). Part of the data is as follows: when the core speed deviation is 0.3 m / s, the tension difference is 0.5 N, and the load is 60%, the corresponding speed correction amount is 2.8 rpm; when the core speed deviation is 0.2 m / s, the tension difference is 0.3 N, and the load is 50%, the correction amount is 1.9 rpm; when the core speed deviation is 0.4 m / s, the tension difference is 0.6 N, and the load is 70%, the correction amount is 3.5 rpm. The parameters that make the predicted speed correction amount and the actual speed correction amount error minimum are calculated by the least square method: if k1=2 rpm / (m / s), k2=1.5 rpm / N, and k3=0.02 rpm / % are calculated, it is indicated that every 1 m / s of core speed deviation requires 2 rpm of speed correction, every 1 N of tension difference requires 1.5 rpm of correction, and every 1% of load requires 0.02 rpm of correction.

[0103] Wherein, the speed influence coefficient is the speed correction amount corresponding to every unit of core speed deviation; the tension influence coefficient is the speed correction amount corresponding to every unit of tension difference; the load influence coefficient is the speed correction amount corresponding to every unit of load; the speed correction amount = speed influence coefficient x core speed deviation absolute value + tension influence coefficient x current tension difference absolute value + load influence coefficient x current load.

[0104] If the core speed deviation is positive, that is, the core speed estimated value is higher than the current actual core speed, there is an acceleration trend in the future, and the tension difference is positive, indicating that the tension of the eccentric side wrapping material is greater than that of the non-eccentric side wrapping material, which will cause the eccentric side wrapping material to break due to excessive stretching, then the speed of the eccentric side servo motor is corrected to the sum of the current speed and the speed correction amount, because increasing the speed of the eccentric side servo motor can increase the speed of releasing the wrapping material, which matches the future acceleration trend of the core, avoiding further widening of the tension difference when the core accelerates due to insufficient supply of the eccentric side wrapping material, thereby balancing the tension on both sides. At the same time, if the speed of the variable frequency motor is less than the set speed of the variable frequency motor, it indicates that the current power is insufficient to support the acceleration of the core, then the speed of the variable frequency motor is corrected to the sum of the current speed and the speed correction amount, to ensure that the core can accelerate smoothly according to the estimated value by increasing the power, avoiding tension fluctuations caused by insufficient power leading to core speed lag.

[0105] If the core speed deviation is positive, and the tension difference is negative, that is, the tension of the non-bias side wrapping material is greater than that of the bias side wrapping material, the non-bias side wrapping material is prone to breakage due to over-tightening, and the speed of the non-bias side servo motor is corrected to the difference between the current speed and the speed correction amount, because reducing the speed of the non-bias side can reduce the release speed of the wrapping material, avoiding the non-bias side wrapping material from being further tightened due to too fast release when the core is accelerating, thereby reducing the tension difference; at the same time, if the load of the frequency conversion motor is greater than the preset proportion of the rated load, it indicates that the current load of the frequency conversion motor is too high, and the core traction force is too strong, which will exacerbate the stress of the non-bias side wrapping material, and the speed of the frequency conversion motor is corrected to the difference between the current speed and the speed correction amount, by reducing the speed to reduce the core traction force, to relieve the tension of the non-bias side wrapping material, to prevent damage to the wrapping material caused by the high load of the frequency conversion motor.

[0106] If the core speed deviation is negative, that is, the estimated core speed is lower than the current actual core speed, there is a trend of deceleration in the future, and the tension difference is negative, that is, the tension of the non-bias side wrapping material is large, and the non-bias side wrapping material is prone to accumulate when the core decelerates, the speed of the bias side servo motor is corrected to the difference between the current speed and the speed correction amount, because reducing the speed of the bias side servo motor can reduce the release of the wrapping material, avoiding the bias side wrapping material from being accumulated due to excessive supply when the core decelerates, while reducing the tension advantage of the non-bias side wrapping material; at the same time, if the speed of the frequency conversion motor is less than the preset proportion of the set speed of the frequency conversion motor, it indicates that the current power of the frequency conversion motor is too weak, and the core may decelerate too much, and the speed of the frequency conversion motor is corrected to the sum of the current speed and the speed correction amount, by appropriately increasing the speed of the frequency conversion motor to maintain the core speed, to avoid the non-bias side wrapping material from being more seriously accumulated due to too fast deceleration, and to ensure uniform wrapping.

[0107] If the core speed deviation is negative, and the tension difference is positive, that is, the tension of the bias side wrapping material is large, and the bias side wrapping material is prone to be over-tightened when the core decelerates, the speed of the non-bias side servo motor is corrected to the difference between the current speed and the speed correction amount, because reducing the speed of the non-bias side servo motor can reduce the release of the wrapping material, avoiding the non-bias side wrapping material from being further tightened due to insufficient release when the core decelerates, balancing the stress of the two sides; at the same time, if the load of the frequency conversion motor is less than the preset proportion of the rated load, it indicates that the current load of the frequency conversion motor is too light, and the core traction force is insufficient, which will lead to too fast deceleration, and the speed of the frequency conversion motor is corrected to the difference between the current speed and the speed correction amount, by appropriately reducing the speed of the frequency conversion motor to match the trend of core deceleration, to avoid the core speed from suddenly dropping due to the light load of the frequency conversion motor, to prevent the bias side wrapping material from being over-tightened due to too slow supply speed, and to ensure the stable state of the wrapping material.

[0108] The preset proportion of the rated load needs to be determined by trial production test in combination with the load bearing capacity of the wrapping material and the rated operating characteristics of the variable frequency motor. First, according to the physical parameters such as the breaking tension and the elastic modulus of the wrapping material, the stress limit of the material under different loads is determined. For example, the glass silk is prone to breakage when the load exceeds 80% of the rated load due to excessive core traction, and the film is prone to excessive stretching when the load exceeds 70%. At the same time, the rated load parameters of the variable frequency motor are referred to, to ensure that the proportion does not exceed the safe operating range of the motor, and to avoid overheating or sudden speed drop of the motor due to excessive load.

[0109] Embodiment 2

[0110] Referring to Figure 2 The embodiment provides an automatic tension regulation method for eccentric wire wrapping head, which comprises the following steps:

[0111] The tension of the wrapping material on the eccentric side and the non-eccentric side, the core speed, the load and the speed of the servo motor and the variable frequency motor, the power supply voltage of the variable frequency motor, and the feedback delay time of the servo motor encoder are acquired in real time; the servo motor is used to adjust the tension of the wrapping material; and the variable frequency motor is used to adjust the core speed;

[0112] The power supply voltage, the load and the speed of the variable frequency motor within a unit time are input into a pre-trained speed prediction model, and a speed deviation prediction value of the variable frequency motor at the next moment is output, and the historical core speed and the transmission ratio within a set time window are combined to calculate a core speed prediction value; the transmission ratio is a conversion coefficient between the speed of the variable frequency motor and the core speed;

[0113] Based on the core speed prediction value, the current core speed and the current speed of the variable frequency motor, the power supply frequency of the frequency converter of the variable frequency motor is adjusted; based on the feedback delay time of the servo motor encoder and the current speed of the servo motor, the speed of the servo motor at the next moment is adjusted;

[0114] Based on the core speed prediction value, the current core speed and the tension of the wrapping material on the eccentric side and the non-eccentric side, the speed of the servo motor and the variable frequency motor at the next moment is adjusted.

[0115] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0116] Finally: the above is only a preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for automatically adjusting the tension of an eccentric wire wrapping, characterized in that, include: Real-time acquisition of tension of the wrapping material on the eccentric and non-eccentric sides, core speed, load and speed of servo motor and variable frequency motor, power supply voltage of variable frequency motor and feedback delay time of servo motor encoder; Servo motors are used to adjust the tension of the wrapping material; Variable frequency motors are used to adjust the speed of the wire core; The power supply voltage, load, and speed of the variable frequency motor per unit time are input into a pre-trained speed prediction model, and the estimated value of the speed deviation of the variable frequency motor at the next moment is output. Combined with the historical core speed and transmission ratio within a set time window, the estimated value of the core speed is calculated. The transmission ratio is the conversion coefficient between the speed of the variable frequency motor and the core speed. Based on the estimated core speed, the current core speed, and the current speed of the variable frequency motor, adjust the power supply frequency of the variable frequency motor's inverter. Based on the feedback delay time of the servo motor encoder and the current speed of the servo motor, adjust the speed of the servo motor at the next moment. Based on the estimated core speed, the current core speed, and the tension of the wrapping material on the eccentric and non-eccentric sides, adjust the speed of the servo motor and the variable frequency motor at the next moment.

2. The method for automatic tension control of eccentric wire wrapping head according to claim 1, characterized in that... Based on the estimated core speed, the corresponding core speed, and the rotational speed of the variable frequency motor, methods for adjusting the power supply frequency of the variable frequency motor's inverter include: The difference between the estimated core speed and the current core speed is calculated to obtain the core speed deviation; The difference between the current speed of the variable frequency motor and the set speed of the variable frequency motor is calculated to obtain the speed fluctuation of the variable frequency motor. Calculate the difference between the current servo motor speed and the set servo motor speed to obtain the servo motor speed fluctuation. The compensation frequency is obtained by calculating the weighted sum of the absolute value of the core speed deviation and the absolute value of the speed fluctuation of the variable frequency motor. When the absolute value of the core speed deviation is greater than the set speed deviation threshold, the inverter outputs the corresponding power supply frequency to the variable frequency motor based on the positive and negative values ​​of the core speed deviation and the speed fluctuation of the variable frequency motor.

3. The method for automatic tension control of eccentric yarn wrapping according to claim 2, characterized in that, Based on the positive and negative values ​​of the wire core speed deviation and the speed fluctuation of the variable frequency motor, the methods for outputting the corresponding power supply frequency from the frequency converter to the variable frequency motor include: If the core speed deviation is positive and the variable frequency motor speed fluctuation is negative, then the variable frequency drive outputs the sum of the current power supply frequency and the compensation frequency to the variable frequency motor. If the core speed deviation is negative and the variable frequency motor speed fluctuation is positive, then the variable frequency drive outputs the difference between the current power supply frequency and the compensation frequency to the variable frequency motor.

4. The method for automatic tension control of eccentric yarn wrapping according to claim 1, characterized in that, Methods for adjusting the servo motor speed at the next moment based on the feedback delay time of the servo motor encoder and the current servo motor speed include: Based on the current servo motor speed, the previous speed, and the feedback delay time of the servo motor encoder, the speed lag is obtained. The corrected speed is obtained by adding the speed lag to the current speed of the servo motor. If the speed lag is not zero, a corrected speed is output to the servo motor.

5. The method for automatic tension control of eccentric yarn wrapping according to claim 1, characterized in that, Based on the estimated core speed, the current core speed, and the tension of the wrapping material on both the eccentric and non-eccentric sides, the methods for adjusting the speeds of the servo motor and the variable frequency motor at the next moment include: The tension difference is obtained by calculating the tension difference between the wrapping materials on the eccentric side and the non-eccentric side; Based on the material of the wrapping material, a safe range for tension difference is pre-set; If the tension difference exceeds the safe range, the speed of the servo motor and the variable frequency motor will be adjusted at the next moment based on the deviation of the wire core speed and the sign of the tension difference.

6. The method for automatic tension control of eccentric yarn wrapping according to claim 5, characterized in that, Based on the sign of the wire core speed deviation and tension difference, the methods for adjusting the speed of the servo motor and the frequency converter motor at the next moment include: Calculate the speed correction amount based on the core speed deviation, the current tension difference, and the current load of the servo motor and the variable frequency motor; If the core speed deviation is positive and the tension difference is positive, then the speed of the eccentric side servo motor will be corrected to the sum of the current speed and the speed correction amount. If the speed of the variable frequency motor is less than the set speed of the variable frequency motor, then the speed of the variable frequency motor will be corrected to the sum of the current speed and the speed correction amount. If the core speed deviation is positive and the tension difference is negative, the speed of the non-eccentric servo motor will be corrected to the difference between the current speed and the speed correction amount. If the load of the variable frequency motor is greater than the rated load of the preset ratio, the speed of the variable frequency motor will be corrected to the difference between the current speed and the speed correction amount. If the core speed deviation is negative and the tension difference is negative, the speed of the eccentric servo motor will be corrected to the difference between the current speed and the speed correction amount. If the speed of the variable frequency motor is less than the speed of the variable frequency motor set by the preset ratio, the speed of the variable frequency motor will be corrected to the sum of the current speed and the speed correction amount. If the core speed deviation is negative and the tension difference is positive, the speed of the non-eccentric servo motor will be corrected to the difference between the current speed and the speed correction amount. If the load of the variable frequency motor is less than the preset ratio of the rated load, the speed of the variable frequency motor will be corrected to the difference between the current speed and the speed correction amount.

7. The method for automatic tension control of eccentric yarn wrapping according to claim 6, characterized in that, The methods for calculating the speed correction amount based on the core speed deviation, current tension difference, and current load of the servo motor and frequency converter motor include: By fitting the wire core speed deviation, tension difference, and load from historical data, along with the corresponding rotational speed correction, the speed influence coefficient, tension influence coefficient, and load influence coefficient are obtained. The speed influence coefficient is the speed correction amount corresponding to each unit of wire core speed deviation; the tension influence coefficient is the speed correction amount corresponding to each unit of tension difference; the load influence coefficient is the speed correction amount corresponding to each unit of load. Rotational speed correction = speed influence coefficient × absolute value of core speed deviation + tension influence coefficient × absolute value of current tension difference + load influence coefficient × current load.

8. The method for automatic tension control of eccentric yarn wrapping according to claim 1, characterized in that, Training methods for speed prediction models include: Collect historical power supply voltage, historical load, and historical speed of the variable frequency motor to form a training set; The training set is preprocessed by removing outliers. The power supply voltage, load and speed of the variable frequency motor at multiple consecutive time points are used as input samples according to the time series, and the speed deviation estimate at the corresponding time point is used as the output label to obtain the preprocessed data. A temporal network architecture is built based on LSTM, and the corresponding hidden layers, neurons and activation functions are set to obtain the initial model; The preprocessed data is divided into training set, test set and validation set according to the proportion. The initial model is trained by backpropagation algorithm and the error of the validation set is monitored in real time. Training is stopped when the error no longer decreases. The initial model performance is evaluated using a test set. If the prediction error exceeds the set range, the initial model parameters are adjusted and the model is retrained until the preset accuracy requirements are met, resulting in a well-trained speed prediction model.

9. The method for automatic tension control of eccentric yarn wrapping according to claim 1, characterized in that, Based on the estimated rotational speed deviation, methods for calculating the estimated core speed by setting historical core speeds and transmission ratios within a time window include: The speed deviation estimate of the variable frequency motor is obtained from the output of the pre-trained speed prediction model. The speed deviation estimate of the variable frequency motor is the difference between the predicted speed and the set speed. Calculate the average historical core velocity within a set time window, and use it as a historical reference value for core velocity; Multiply the estimated rotational speed deviation by the transmission ratio to obtain the estimated core speed deviation. The estimated core speed is obtained by adding the historical reference value of the core speed to the estimated core speed deviation.

10. An automatic tension control system for eccentric yarn wrapping, used to implement the automatic tension control method for eccentric yarn wrapping as described in any one of claims 1-9, characterized in that, include: The data acquisition module is used to acquire in real time the tension of the wrapping material on the eccentric and non-eccentric sides, the core speed, the load and speed of the servo motor and the variable frequency motor, the power supply voltage of the variable frequency motor, and the feedback delay time of the servo motor encoder. The speed prediction module is used to input the power supply voltage, load and speed of the variable frequency motor per unit time into the pre-trained speed prediction model, output the speed deviation estimate of the variable frequency motor at the next moment, and calculate the core speed estimate by combining the historical core speed and transmission ratio within the set time window. The motor adjustment module adjusts the power supply frequency of the inverter for the variable frequency motor based on the estimated core speed, the current core speed, and the current speed of the variable frequency motor. Based on the feedback delay time of the servo motor encoder and the current speed of the servo motor, adjust the speed of the servo motor at the next moment. The speed adjustment module adjusts the speed of the servo motor and the frequency converter motor at the next moment based on the estimated core speed, the current core speed, and the tension of the wrapping material on the eccentric and non-eccentric sides.

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