Stirring head temperature control method and system, medium and product

Abstract

The invention discloses a stirring head temperature control method and system, a medium and a product, and relates to the field of electric digital data processing. By implementing the application, the control system acquires the temperature data of the needle part and the shoulder part of the stirring head in real time, and predicts the temperature of the needle part and the temperature of the shoulder part within the future preset duration by using the temperature prediction model in combination with the cooling liquid flow of the needle part and the shoulder part. When the deviation between the predicted temperature and the target temperature exceeds the temperature threshold value, the control system can calculate and adjust the flow of the cooling liquid in time, and accurate dynamic control over the temperature of the stirring head is achieved. According to the predictive temperature control method, the machining quality problem caused by too large temperature fluctuation of the stirring head can be prevented, and the stability and controllability of the welding process are improved. Meanwhile, the control system controls the cooling liquid flow of the needle part and the shoulder part respectively, finer temperature adjustment is achieved, and the phenomenon of local supercooling or superheating caused by a traditional single cooling mode is avoided.

Description

Technical Field

[0001] This application relates to the field of electrical digital data processing, and particularly to a method for controlling the temperature of a stirring head, a control system, a medium, and a product. Background Art

[0002] Friction stir welding is a solid-state joining technology that has been widely used in fields such as aerospace, rail transit, and automotive manufacturing. During the friction stir welding process, the control of the stirring head temperature plays a crucial role in the welding quality. Excessive temperature will cause a decrease in the weld strength, while too low temperature will result in insufficient welding. Therefore, precise control of the stirring head temperature is required.

[0003] Currently, in industrial production, the temperature of the stirring head is generally controlled by setting the coolant flow rate according to the welding process parameters. Specifically, according to different welding materials, welding speeds and other process parameters, the flow rates of the needle coolant and the shoulder coolant are preset in advance, and a fixed flow rate is maintained for cooling during the welding process to control the temperature of the stirring head.

[0004] However, the cooling method with a fixed flow rate has certain limitations in practical applications. Due to factors such as the dynamic change of the workpiece temperature distribution during the welding process and the fluctuation of the external environmental temperature, the cooling method with a fixed flow rate is difficult to respond to temperature changes in a timely manner. During the welding process, the temperature of the stirring head is prone to fluctuate, resulting in unstable weld quality and affecting the welding effect. Summary of the Invention

[0005] This application provides a method for controlling the temperature of a stirring head, a control system, a medium, and a product, which is used to prevent processing quality problems caused by excessive temperature fluctuations of the stirring head, and improves the stability and controllability of the welding process.

[0006] First aspect, the present application provides a method for controlling the temperature of a stirring head, which is applied to a control system. The method includes: collecting the needle part temperature data and the shoulder part temperature data of the stirring head, where the needle part temperature data includes the current temperature of the needle part and the temperature change rate of the needle part, and the shoulder part temperature data includes the current temperature of the shoulder part and the temperature change rate of the shoulder part; inputting the needle part temperature data, the shoulder part temperature data, the coolant flow rate of the needle part, and the coolant flow rate of the shoulder part into a temperature prediction model to obtain the predicted temperature of the needle part and the predicted temperature of the shoulder part within a preset future time period, where the coolant flow rate of the needle part refers to the coolant flow rate in the current needle part cooling channel, and the coolant flow rate of the shoulder part refers to the coolant flow rate in the current shoulder part cooling channel; when the deviation between the predicted temperature of the needle part and the preset target temperature of the needle part exceeds the first temperature threshold and / or the deviation between the predicted temperature of the shoulder part and the preset target temperature of the shoulder part exceeds the second temperature threshold, calculating the target flow rate of the needle part and / or the target flow rate of the shoulder part; adjusting the coolant flow rate of the needle part cooling channel and / or the shoulder part cooling channel to reach the target flow rate of the needle part and / or the target flow rate of the shoulder part.

[0007] By adopting the above technical solution, the control system collects the temperature data of the needle part and the shoulder part of the stirring head in real time, combines the coolant flow rates of the needle part and the shoulder part, and uses the temperature prediction model to predict the temperature of the needle part and the shoulder part within a preset future time period. When the deviation between the predicted temperature and the target temperature exceeds the temperature threshold, the control system can calculate and adjust the coolant flow rate in time, realizing precise dynamic control of the temperature of the stirring head. This predictive temperature control method can prevent processing quality problems caused by excessive temperature fluctuations of the stirring head, improving the stability and controllability of the welding process. At the same time, the control system realizes more refined temperature adjustment by separately controlling the coolant flow rates of the needle part and the shoulder part, avoiding local overcooling or overheating phenomena caused by traditional single cooling methods.

[0008] Combined with some embodiments of the first aspect, in some embodiments, after the step of collecting the needle part temperature data and the shoulder part temperature data of the stirring head, where the needle part temperature data includes the current temperature of the needle part and the temperature change rate of the needle part, and the shoulder part temperature data includes the current temperature of the shoulder part and the temperature change rate of the shoulder part, the method further includes: if the temperature change rate of the needle part and / or the temperature change rate of the shoulder part exceeds the preset rate threshold, adjusting the coolant flow rate of the needle part cooling channel to the preset maximum needle part flow rate and / or adjusting the coolant flow rate of the shoulder part cooling channel to the preset maximum shoulder part flow rate, and reducing the rotation speed of the stirring head to the preset safe rotation speed; after a preset time period, if the temperature change rate of the needle part and / or the temperature change rate of the shoulder part still exceeds the preset rate threshold, controlling the stirring head to stop.

[0009] By adopting the above technical solution, when the temperature change rate at the needle part and / or the shoulder part exceeds the preset rate threshold, the control system will immediately adjust the coolant flow rate to the maximum and reduce the rotational speed of the stirring head. This rapid response mechanism can effectively prevent the stirring head from being damaged due to rapid temperature changes. If the temperature change rate at the needle part and / or the shoulder part is still too large after the preset duration, the control system will automatically shut down for protection. This dual protection mechanism greatly improves the safety and reliability of the equipment, can detect and handle temperature anomalies in a timely manner, avoid equipment damage and processing quality problems caused by temperature runaway, and ensures the safety of the friction stir welding process.

[0010] Combined with some embodiments of the first aspect, in some embodiments, before the step of calculating the target flow rate of the needle part and / or the target flow rate of the shoulder part when the deviation between the predicted temperature of the needle part and the preset target temperature of the needle part exceeds the first temperature threshold and / or the deviation between the predicted temperature of the shoulder part and the preset target temperature of the shoulder part exceeds the second temperature threshold, the method further includes: obtaining the operating parameters of the stirring head, where the operating parameters include the rotational speed of the stirring head, the axial pressure, and the stirring depth; inputting the operating parameters into the first temperature formula and the second temperature formula respectively to obtain the preset target temperature of the needle part and the preset target temperature of the shoulder part; the first temperature formula is: Tn = T0 + k1×P - k2×R + k3×D; the second temperature formula is: Ts = T0 + k4×P - k5×R - k6×D; where, Tn is the preset target temperature of the needle part, Ts is the preset target temperature of the shoulder part, T0 is the preset reference temperature, P is the axial pressure, R is the rotational speed of the stirring head, D is the stirring depth, k1 is the pressure-temperature coefficient of the needle part, k2 is the rotational speed-temperature coefficient of the needle part, k3 is the depth-temperature coefficient of the needle part, k4 is the pressure-temperature coefficient of the shoulder part, k5 is the rotational speed-temperature coefficient of the shoulder part, and k6 is the depth-temperature coefficient of the shoulder part.

[0011] By adopting the above technical solution, the control system establishes a mathematical relationship between the operating parameters of the stirring head (the rotational speed of the stirring head, the axial pressure, and the stirring depth) and the preset target temperature of the top part and the preset target temperature of the shoulder part, realizing the dynamic calculation of the target temperature. The adopted temperature formula takes into account the different effects of the rotational speed of the stirring head, the axial pressure, and the stirring depth on the temperature of the needle part and the shoulder part, and reflects the contribution degree of each operating parameter to the temperature through different temperature coefficients. This temperature control method based on a physical model makes the temperature control more scientific and accurate, can automatically adjust the target temperature according to the change of process parameters, improves the adaptability and accuracy of temperature control, and further enhances the stability of welding quality.

[0012] In some embodiments in combination with some embodiments of the first aspect, before the step of inputting the needle part temperature data, the shoulder part temperature data, the needle part coolant flow rate, and the shoulder part coolant flow rate into a temperature prediction model to obtain the predicted needle part temperature and the predicted shoulder part temperature within a preset future time period, where the needle part coolant flow rate refers to the coolant flow rate in the current needle part cooling channel and the shoulder part coolant flow rate refers to the coolant flow rate in the current shoulder part cooling channel, the method further includes: obtaining the needle part profile data and the shoulder part profile data of the stirring head to determine wear characteristic parameters, where the wear characteristic parameters include the wear depth, wear area, and surface roughness of the needle part and the shoulder part; determining the needle part frictional heat data and the shoulder part frictional heat data based on the wear characteristic parameters; calculating the heat dissipation amount of the needle part and the heat dissipation amount of the shoulder part per unit time according to the needle part frictional heat data and the shoulder part frictional heat data; detecting the working parameters of the needle part cooling channel and the shoulder part cooling channel, where the working parameters include the pressure difference between the inlet and outlet, the coolant temperature, and the channel cross-sectional area; and calculating the needle part coolant flow rate and the shoulder part coolant flow rate based on the heat dissipation amount of the needle part, the heat dissipation amount of the shoulder part, and the working parameters.

[0013] By adopting the above technical solution, the control system obtains the needle part profile data and the shoulder part profile data of the stirring head, comprehensively evaluates its wear state, including wear characteristic parameters such as wear depth, wear area, and surface roughness. Based on these wear characteristic parameters, the control system can accurately calculate the frictional heat data and the heat dissipation amount, and combine with the working parameters of the cooling channel (pressure difference between the inlet and outlet, coolant temperature, and channel cross-sectional area) to achieve accurate calculation of the coolant flow rate. This temperature control method considering the tool wear state overcomes the defect of the traditional method ignoring the influence of tool wear, making the temperature control more in line with the actual working conditions. At the same time, the control system monitors the working parameters of the cooling channel in real time, ensuring the effectiveness of the cooling system and improving the reliability and accuracy of temperature control.

[0014] In some embodiments in combination with some embodiments of the first aspect, specifically determining the needle part frictional heat data includes: obtaining the material parameters of the needle part, where the material parameters include the thermal conductivity coefficient, specific heat capacity, and density; calculating the actual contact area between the needle part and the workpiece based on the wear depth and wear area of the needle part, and determining the dynamic friction coefficient of the needle part according to the surface roughness of the needle part; and substituting the material parameters, the operating parameters, the actual contact area, and the dynamic friction coefficient into the needle part heat dissipation amount calculation formula to obtain the heat dissipation amount of the needle part per unit time.

[0015] By adopting the above technical solution, when determining the friction heat data of the needle part, the control system comprehensively considers the material properties of the needle part (thermal conductivity coefficient, specific heat capacity, and density) and the actual working condition parameters, and establishes a more accurate calculation formula for the heat dissipation of the needle part. This heat dissipation calculation method based on multiple parameters overcomes the limitations of traditional simplified calculation methods, can more accurately reflect the heat generation situation in the actual processing process, combines the tool wear state with the heat generation mechanism, makes the temperature control more in line with physical reality, and improves the accuracy of temperature prediction and control.

[0016] Combined with some embodiments of the first aspect, in some embodiments, based on the heat dissipation of the needle part, the heat dissipation of the shoulder part, and the working parameters, the coolant flow rates of the needle part and the shoulder part are calculated. Specifically, it includes: calculating the reference coolant flow rate according to the pressure difference between the inlet and outlet and the cross-sectional area of the channel; calculating the minimum cooling flow rate required for the needle part based on the heat dissipation of the needle part and the coolant temperature in the coolant channel of the needle part; calculating the minimum cooling flow rate required for the shoulder part based on the heat dissipation of the shoulder part and the coolant temperature in the coolant channel of the shoulder part; when the reference coolant flow rate is less than the minimum cooling flow rate required for the needle part, increasing the pump pressure of the coolant channel of the needle part to increase the pressure difference between the inlet and outlet; substituting the increased pressure difference between the inlet and outlet into the preset flow rate calculation formula to obtain the coolant flow rate of the needle part; when the reference coolant flow rate is less than the minimum cooling flow rate required for the shoulder part, increasing the pump pressure of the coolant channel of the shoulder part to increase the pressure difference between the inlet and outlet; substituting the increased pressure difference between the inlet and outlet into the preset flow rate calculation formula to obtain the coolant flow rate of the shoulder part; when the reference coolant flow rate is greater than the minimum cooling flow rate required for the needle part, determining the minimum cooling flow rate required for the needle part as the coolant flow rate of the needle part; when the reference coolant flow rate is greater than the minimum cooling flow rate required for the shoulder part, determining the minimum cooling flow rate required for the shoulder part as the coolant flow rate of the shoulder part.

[0017] By adopting the above technical solution, the control system establishes a complete set of coolant flow rate calculation and adjustment mechanisms. First, the control system calculates the reference coolant flow rate, and then determines the minimum cooling flow rate according to the heat dissipation requirements. When the reference coolant flow rate is insufficient, the control system increases the coolant flow rate by increasing the pump pressure; when the reference coolant flow rate is sufficient, the control system adopts the minimum required flow rate. This intelligent flow rate adjustment scheme not only ensures sufficient cooling effect but also avoids excessive use of coolant, realizes on-demand adjustment of the cooling system, improves energy utilization efficiency, and at the same time ensures the reliability and economy of temperature control.

[0018] In combination with some embodiments of the first aspect, in some embodiments, before the step of collecting the temperature data of the needle part and the shoulder part of the collecting and stirring head, the method further includes: obtaining the ambient temperature and the ambient humidity; determining whether the ambient temperature and the ambient humidity meet the working conditions of friction stir welding; if they meet, starting the stirring head; if they do not meet, adjusting the ambient temperature and the ambient humidity to meet the working conditions of friction stir welding.

[0019] By adopting the above technical solution, the control system performs a pre-inspection of the environmental conditions before starting the stirring head to ensure that the processing environment meets the process requirements. This preventive environmental management mechanism can avoid processing quality problems caused by improper environmental conditions, ensure suitable environmental conditions before processing, improve the stability and reliability of the process, provide necessary environmental guarantees for the smooth implementation of the friction stir welding process, and reduce process fluctuations caused by environmental factors.

[0020] In a second aspect, an embodiment of the present application provides a control system, which includes: one or more processors and a memory; the memory is coupled to the one or more processors, and the memory is used to store computer program code, and the computer program code includes computer instructions, and the one or more processors call the computer instructions to enable the control system to execute the method described in the first aspect and any possible implementation manner in the first aspect.

[0021] In a third aspect, an embodiment of the present application provides a computer program product containing instructions, and when the above computer program product runs on a control system, it enables the above control system to execute the method described in the first aspect and any possible implementation manner in the first aspect.

[0022] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, including instructions, and when the above instructions run on a control system, it enables the above control system to execute the method described in the first aspect and any possible implementation manner in the first aspect.

[0023] It can be understood that the control system provided in the second aspect, the computer program product provided in the third aspect, and the computer storage medium provided in the fourth aspect are all used to execute the method provided in the embodiments of the present application. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method, and will not be elaborated here.

[0024] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. By adopting the above technical solution, the control system collects the temperature data of the pin part and the shoulder part of the stirring head in real time, and combines the coolant flow rates of the pin part and the shoulder part. Using the temperature prediction model, it predicts the pin part temperature and the shoulder part temperature within a preset future time period. When the deviation between the predicted temperature and the target temperature exceeds the temperature threshold, the control system can calculate and adjust the coolant flow rate in a timely manner, achieving precise dynamic control of the stirring head temperature. This predictive temperature control method can prevent processing quality problems caused by excessive temperature fluctuations of the stirring head, improving the stability and controllability of the welding process. At the same time, by separately controlling the coolant flow rates of the pin part and the shoulder part, the control system realizes more refined temperature adjustment, avoiding local overcooling or overheating phenomena caused by traditional single cooling methods.

[0025] 2. By adopting the above technical solution, the control system establishes the mathematical relationship between the operating parameters of the stirring head (stirring head rotation speed, axial pressure, and stirring depth) and the preset top target temperature and the preset shoulder target temperature, realizing the dynamic calculation of the target temperature. The adopted temperature formula takes into account the different effects of the stirring head rotation speed, axial pressure, and stirring depth on the pin part temperature and the shoulder part temperature, and reflects the contribution degree of each operating parameter to the temperature through different temperature coefficients. This temperature control method based on a physical model makes the temperature control more scientific and accurate, can automatically adjust the target temperature according to the changes in process parameters, improving the adaptability and accuracy of temperature control, and thus enhancing the stability of welding quality.

[0026] 3. By adopting the above technical solution, the control system obtains the pin part contour data and the shoulder part contour data of the stirring head, comprehensively evaluates its wear state, including wear feature parameters such as wear depth, wear area, and surface roughness. Based on these wear feature parameters, the control system can accurately calculate the friction heat data and the heat dissipation amount, and combine the working parameters of the cooling channel (inlet and outlet pressure difference, coolant temperature, and channel cross-sectional area) to achieve the precise calculation of the coolant flow rate. This temperature control method considering the tool wear state overcomes the defect of traditional methods ignoring the influence of tool wear, making the temperature control more in line with the actual working conditions. At the same time, the control system monitors the working parameters of the cooling channel in real time, ensuring the effectiveness of the cooling system and improving the reliability and accuracy of temperature control. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flowchart of a method for controlling the temperature of the stirring head in an embodiment of the present application; Figure 2 is another flowchart of a method for controlling the temperature of the stirring head in an embodiment of the present application; Figure 3 is a structural schematic diagram of a stirring head in an embodiment of the present application; Figure 4It is a schematic structural diagram of an entity device in the control system in the embodiments of the present application. Detailed implementation manners

[0028] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. As used in the specification of the present application, the singular forms "a", "an", "the above", "the", and "this" are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in the present application refers to any or all possible combinations including one or more of the listed items.

[0029] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as implying or suggesting relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0030] The following describes the process of the method provided in this embodiment. Please refer to Figure 1 , which is a schematic flowchart of a method for controlling the temperature of the stirring head in the embodiments of the present application.

[0031] S101. Collect the needle part temperature data and the shoulder part temperature data of the stirring head. The needle part temperature data includes the current temperature of the needle part and the temperature change rate of the needle part, and the shoulder part temperature data includes the current temperature of the shoulder part and the temperature change rate of the shoulder part; Among them, the stirring head refers to the main tool for friction stir welding, including two main parts: the needle part and the shoulder part; the needle part refers to the central protruding part of the stirring head, which is used to insert into the workpiece and generate a stirring effect; the shoulder part refers to the flat disc-shaped structure surrounding the needle part, which is used to prevent material overflow and provide additional heat; the needle part temperature data and the shoulder part temperature data refer to the temperature-related information collected by the temperature sensor; the current temperature of the needle part and the current temperature of the shoulder part refer to the real-time temperature values of the needle part and the shoulder part at a specific moment, with the unit of degree Celsius; the temperature change rate of the needle part and the temperature change rate of the shoulder part are used to represent the change amount of the needle part temperature and the change amount of the shoulder part temperature per unit time, usually in the unit of degree Celsius per second.

[0032] Specifically, the control system continuously collects temperature data at a preset sampling frequency (such as 10 Hz) through multiple temperature sensors arranged on the needle part and the shoulder part. For each sampling point, the control system simultaneously records the instantaneous temperature values of the needle part and the shoulder part, and obtains the temperature change rate by dividing the temperature difference between adjacent sampling points by the preset sampling time interval.

[0033] S102. Input the needle part temperature data, shoulder part temperature data, needle part coolant flow rate, and shoulder part coolant flow rate into the temperature prediction model to obtain the predicted needle part temperature and predicted shoulder part temperature within a preset future duration. The needle part coolant flow rate refers to the coolant flow rate in the current needle part cooling channel, and the shoulder part coolant flow rate refers to the coolant flow rate in the current shoulder part cooling channel; Among them, the temperature prediction model refers to a mathematical model used to predict future temperature changes; the preset future duration refers to the time span for which temperature prediction is required, usually several seconds; the needle part cooling channel refers to the pipeline system provided in the needle part for passing coolant; the shoulder part cooling channel refers to the pipeline system provided in the shoulder part for passing coolant; the coolant flow rate is used to represent the volume of coolant passing through the cooling channel per unit time, usually in liters per minute; the predicted needle part temperature and predicted shoulder part temperature represent the needle part temperature value and shoulder part temperature value at a future moment calculated by the temperature prediction model.

[0034] Specifically, the control system inputs the collected needle part temperature data and the coolant flow rate in the current needle part cooling channel into a pre-trained temperature prediction model (such as an LSTM model based on deep learning or a physical mechanism model). This temperature prediction model takes into account multiple factors such as the historical trend of needle part temperature changes, cooling effect, heat generation, etc., and can predict the temperature changes of the needle part within the next 5 - 10 seconds. The prediction result includes the temperature change curve of the needle part during this period, providing a decision basis for subsequent flow rate adjustment. The processing method for the shoulder part temperature data and the coolant flow rate in the current shoulder part cooling channel is the same. The control system will evaluate the accuracy of the prediction result in real time and perform online fine-tuning on the temperature prediction model according to the actual temperature feedback to improve the prediction accuracy.

[0035] The steps to build a temperature prediction model based on deep learning are as follows: First, the control system collects the needle part temperature, shoulder part temperature, needle part coolant flow rate, and shoulder part coolant flow rate at multiple measurement points within a preset past duration (such as within 6 months). The needle part temperature and shoulder part temperature are the real-time temperature values at each position collected by the control system. The needle part coolant flow rate and shoulder part coolant flow rate are the volume of coolant flowing through the cooling channel per second collected by the control system. The control system stores the collected needle part temperature and needle part coolant flow rate in the dataset D in chronological order, and the format of each piece of data is (needle part temperature, needle part coolant flow rate). Similarly, the control system stores the collected shoulder part temperature and shoulder part coolant flow rate in the dataset D in chronological order, and the format of each piece of data is (shoulder part temperature, shoulder part coolant flow rate). Among them, the current needle part temperature, shoulder part temperature, needle part coolant flow rate, and shoulder part coolant flow rate are the input features for model training, and the needle part temperature and shoulder part temperature at future moments are the output features for model training.

[0036] Then, the control system constructs a recurrent neural network based on LSTM, which includes an input layer, two LSTM hidden layers, a fully connected layer, and an output layer. The input layer inputs the needle temperature, shoulder temperature, needle coolant flow rate, and shoulder coolant flow rate. The number of nodes in the hidden layer is set to 64, and the number of nodes in the fully connected layer is set to 32. The output layer outputs the predicted needle temperature and predicted shoulder temperature within a preset future time period.

[0037] Next, the control system uses the Adam optimizer with a learning rate set to 0.001 and a training batch size of 32, which can also be set according to the actual situation and is not limited here. 80% of the historical data is divided into the training set, and 20% is divided into the validation set. It is trained for 100 epochs, and the model with the highest accuracy on the validation set is saved, which can also be set according to the actual situation and is not limited here. An epoch is the process of the entire training dataset passing through the neural network once. In machine learning and deep learning, an epoch is a unit used to measure the number of times the entire training set is repeatedly learned. Specifically, when the neural network completes a forward calculation and a backward propagation process, that is, all data has been processed by the network once, one epoch is completed. The control system uses binary cross-entropy as the loss function and adopts Early Stopping to prevent overfitting. When the value of the loss function exceeds the preset function threshold, it is determined that the model training is completed, and the temperature prediction model is obtained. Early Stopping is a technique in deep learning and machine learning to prevent model overfitting. It decides when to stop training by monitoring the performance of the model on the validation set.

[0038] Finally, the control system inputs the input features in the validation set into the temperature prediction model, then obtains the predicted output of the temperature prediction model, compares the predicted output of the temperature prediction model with the actual output features in the validation set, and uses some performance metrics such as accuracy, precision, recall, F1-score, mean squared error (MSE), etc. to evaluate the performance of the temperature prediction model. According to the performance of the temperature prediction model on the validation set, adjust the parameters of the temperature prediction model, including adjusting the learning rate, changing the model complexity (such as increasing or decreasing the number of layers or nodes in the neural network), modifying the regularization strength, etc. This process may require multiple iterations, each time adjusting based on the previous learning results to optimize the temperature prediction model.

[0039] S103. When the deviation between the predicted needle temperature and the preset needle target temperature exceeds the first temperature threshold and / or the deviation between the predicted shoulder temperature and the preset shoulder target temperature exceeds the second temperature threshold, calculate the needle target flow rate and / or the shoulder target flow rate; Among them, the preset needle part target temperature refers to the optimal working temperature of the needle part determined according to the process requirements; the preset shoulder part target temperature refers to the optimal working temperature of the shoulder part determined according to the process requirements; the temperature deviation is used to represent the difference between the predicted temperature and the target temperature; the first temperature threshold refers to the maximum temperature deviation allowed for the needle part; the second temperature threshold refers to the maximum temperature deviation allowed for the shoulder part; the needle part target flow rate is used to represent the ideal coolant flow rate required to maintain the temperature of the needle part; the shoulder part target flow rate represents the ideal coolant flow rate required to maintain the temperature of the shoulder part.

[0040] Specifically, the control system compares the predicted temperature of the needle part with the preset needle part target temperature, and compares the predicted temperature of the shoulder part with the preset shoulder part target temperature. When the deviation between the predicted temperature of the needle part and the preset needle part target temperature exceeds the first temperature threshold (such as ±15°C) or the deviation between the predicted temperature of the shoulder part and the preset shoulder part target temperature exceeds the second temperature threshold (such as ±20°C), the control system starts the flow rate adjustment calculation program. This flow rate adjustment calculation program calculates the coolant flow rate required to maintain the preset needle part target temperature and / or the preset shoulder part target temperature based on the heat conduction equation and the magnitude of the temperature deviation, combined with the cooling efficiency model. The calculation process takes into account the temperature change rate, the heat accumulation effect, and the response characteristics of the cooling system, and obtains the optimal needle part target flow rate and / or shoulder part target flow rate through iterative optimization. For the heating and cooling scenarios, the control system adopts different calculation strategies to ensure the accuracy and rapidity of the adjustment.

[0041] S104. Adjust the coolant flow rate of the needle part cooling channel and / or the shoulder part cooling channel to reach the needle part target flow rate and / or the shoulder part target flow rate.

[0042] Specifically, the control system checks the working state of the current cooling system, including parameters such as pump pressure, valve opening, and pipeline pressure. Then, the control system calculates the required adjustment amount according to the difference between the target flow rate and the current flow rate. For the needle part cooling channel, the control system changes the flow rate by adjusting the rotation speed of the liquid supply pump and controlling the opening of the valve. The adjustment process uses the PID control algorithm to achieve a smooth transition. For the shoulder part cooling channel, a similar adjustment method is adopted. The control system will monitor the flow rate change in real time. When the deviation between the actual flow rate and the target flow rate is less than the preset value (such as ±5%), this adjustment is completed. At the same time, the control system will record the parameter changes during the adjustment process for optimizing the subsequent control strategy. If the target flow rate cannot be reached within the preset time, the control system will issue a warning message and start the standby adjustment plan.

[0043] By adopting the above technical solution, the control system collects the temperature data of the pin and shoulder of the stirring head in real time, and combines the coolant flow rates of the pin and shoulder. Using the temperature prediction model, it predicts the pin temperature and shoulder temperature within a preset future duration. When the deviation between the predicted temperature and the target temperature exceeds the temperature threshold, the control system can calculate and adjust the coolant flow rate in a timely manner, achieving precise dynamic control of the stirring head temperature. This predictive temperature control method can prevent processing quality problems caused by excessive temperature fluctuations of the stirring head, improving the stability and controllability of the welding process. At the same time, by separately controlling the coolant flow rates of the pin and shoulder, the control system achieves more refined temperature adjustment, avoiding local overcooling or overheating phenomena caused by traditional single cooling methods.

[0044] The following further describes the more specific process of the method provided in this embodiment. Please refer to Figure 2 , which is another process schematic diagram of the stirring head temperature control method in the embodiment of the present application.

[0045] S201. Obtain the ambient temperature and ambient humidity; determine whether the ambient temperature and ambient humidity meet the friction stir welding working conditions.

[0046] Among them, the ambient temperature refers to the air temperature in the friction stir welding processing area, with the unit of degree Celsius; the ambient humidity refers to the moisture content in the air in the friction stir welding processing area, usually expressed as a relative humidity percentage; the friction stir welding working conditions are used to represent the range of environmental parameters required for the normal operation of the equipment.

[0047] Specifically, the control system simultaneously collects the temperature data and humidity data of multiple measurement points through multiple temperature and humidity sensors distributed in the processing area. The control system performs average processing on the collected data to eliminate the influence of local fluctuations. The temperature judgment standard is usually 15 - 35 °C, and the humidity judgment standard is usually 30% - 70% relative humidity. The control system also considers the change trend of temperature and humidity. If a rapid change trend is detected, even if the current value is within the range, it may be determined that the friction stir welding working conditions are not met.

[0048] S202. If satisfied, start the stirring head.

[0049] Specifically, the control system first conducts equipment self - inspection to confirm that the states of all components are normal, and then gradually increases the rotation speed of the stirring head according to the preset start - up curve, usually using a segmented acceleration method, such as first accelerating to 50% of the rated speed and running stably for 10 seconds, and then continuing to accelerate to the working speed. The control system monitors parameters such as motor current, bearing temperature, and vibration in real time during the start - up process. If any abnormality is found, the start - up program will be immediately interrupted.

[0050] S203. If not satisfied, adjust the ambient temperature and ambient humidity to meet the friction stir welding working conditions.

[0051] Specifically, the control system analyzes the deviation type and degree of environmental parameters, such as too high temperature, too high humidity, etc. According to the deviation type and degree, the control system formulates adjustment strategies, such as starting the refrigeration system to cool down, turning on the dehumidifier to reduce humidity, etc. When it is detected that the environmental parameters are close to the friction stir welding working conditions, the control system will reduce the adjustment intensity to avoid overshooting.

[0052] S204. Collect the needle part temperature data and shoulder part temperature data of the stirring head. The needle part temperature data includes the current temperature of the needle part and the temperature change rate of the needle part. The shoulder part temperature data includes the current temperature of the shoulder part and the temperature change rate of the shoulder part.

[0053] Specifically, reference can be made to step S101, which will not be elaborated here.

[0054] S205. If the temperature change rate of the needle part and / or the temperature change rate of the shoulder part exceeds the preset rate threshold, adjust the coolant flow rate of the needle part cooling channel to the preset maximum needle part flow rate and / or adjust the coolant flow rate of the shoulder part cooling channel to the preset maximum shoulder part flow rate, and reduce the rotation speed of the stirring head to the preset safe rotation speed.

[0055] Among them, the preset rate threshold is used to represent the safety upper limit value of the temperature change rate of the needle part and the temperature change rate of the shoulder part, usually in degrees Celsius per second; the preset maximum needle part flow rate refers to the maximum coolant flow rate that the needle part cooling channel can withstand; the preset maximum shoulder part flow rate refers to the maximum coolant flow rate that the shoulder part cooling channel can withstand; the preset safe rotation speed refers to the target rotation speed at which the stirring head runs at a reduced speed when an abnormality occurs.

[0056] Specifically, the control system quickly evaluates the temperature change rate of the needle part and the temperature change rate of the shoulder part. If the temperature change rate of the needle part exceeds the preset threshold (such as 2 °C / s) or the temperature change rate of the shoulder part exceeds the preset threshold (such as 1.5 °C / s), immediately start the emergency procedure. The control system simultaneously performs three actions: quickly increase the flow rate of the needle part cooling channel to the maximum value (such as 20 L / min), increase the flow rate of the shoulder part cooling channel to the maximum value (such as 25 L / min), and reduce the rotation speed of the stirring head to the preset safe rotation speed (such as 60% of the rated rotation speed). The control system adopts a fast response control strategy to ensure that the adjustment of various parameters is completed within 0.5 seconds.

[0057] S206. After the preset duration, if the temperature change rate of the needle part and / or the temperature change rate of the shoulder part still exceeds the preset rate threshold, then control the stirring head to stop.

[0058] Among them, the preset duration represents the waiting time for observing the temperature change trend, usually several seconds; stopping means making the stirring head completely stop running according to the safety procedure.

[0059] Specifically, after adjusting the parameters, the control system continuously monitors the temperature change within a preset duration (usually 10 - 15 seconds). If the temperature change rate of the needle part and / or the temperature change rate of the shoulder part still exceeds the preset rate threshold during this period, it indicates that the cooling measures are not effective enough, and the control system will initiate the shutdown procedure. The shutdown process is divided into three stages: First, the rotation speed of the stirring head is reduced to the lowest (such as 100 rpm) and maintained for 5 seconds. Then, the main shaft power is cut off while the cooling system operates at full power. Finally, after confirming that the temperature starts to drop, the cooling system is gradually shut down. The entire shutdown process lasts about 30 seconds, and the control system will record the parameter changes throughout the process.

[0060] S207. Obtain the needle profile data and shoulder profile data of the stirring head to determine the wear characteristic parameters. The wear characteristic parameters include the wear depth, wear area, and surface roughness of the needle part and the shoulder part.

[0061] Among them, the needle profile data is used to represent the digital information of the needle part's outer dimension and surface shape, including geometric parameters such as height and diameter; the shoulder profile data is used to represent the digital information of the shoulder part's outer dimension and surface shape, including parameters such as diameter and inclination angle; the wear depth is used to represent the loss depth of the tool surface relative to the original state, with the unit of millimeter; the wear area is used to represent the planar projection area of the damaged part of the tool surface, with the unit of square millimeter; the surface roughness is the statistical characteristic value of the surface microgeometry, usually represented by the Ra value.

[0062] Specifically, the control system performs profile scanning on the stirring head in a stationary state through a equipped high-precision laser scanning system. The scanning process adopts a multi-point measurement method. 36 measurement points are set in the needle part area, with an interval of 10 degrees; 72 measurement points are set in the shoulder part area, with an interval of 5 degrees. After the original data collected by the control system is denoised, it is compared with the standard CAD model to calculate the wear depth distribution map. For the wear area, the control system uses an image processing algorithm to identify the boundary of the wear area and calculate the area value. The surface roughness is obtained by measuring with a micro profiler, and multiple sampling points are selected for measurement in the main stress area. All measurement data are digitally filtered and validity verified to ensure the accuracy of the data.

[0063] S208. Based on the wear characteristic parameters, determine the frictional heat data of the needle part and the frictional heat data of the shoulder part.

[0064] Among them, the frictional heat data refers to the heat information generated during the contact process between the stirring head and the workpiece.

[0065] Specifically, the control system corrects the friction coefficient according to the wear characteristic parameters. For every 0.1 mm increase in wear depth, the friction coefficient is adjusted by 0.02; for every 1 μm increase in surface roughness, the friction coefficient is adjusted by 0.01. Then, the control system combines the process parameters (rotation speed, pressure) and the corrected friction coefficient, and uses the heat generation model to calculate the frictional heat of the needle part and the shoulder part. The calculation process takes into account the influence of different wear degrees on the contact area and adjusts the heat distribution coefficient according to the wear morphology. The control system adopts a zoning calculation method, divides the needle part and the shoulder part into multiple calculation units respectively, obtains a more accurate heat distribution, and the calculation results include the heat flux density and the total heat generation rate of each region.

[0066] The following lists a specific calculation example to illustrate this process. Assume the initial conditions are: standard friction coefficient μ0 = 0.3, process parameters: rotation speed = 1000 rpm, axial pressure = 10 kN, initial diameter of the needle part = 8 mm, initial diameter of the shoulder part = 24 mm. When the following wear characteristic parameters are detected: 1. Wear condition of the needle part: Wear depth = 0.3 mm (increasing the friction coefficient by 0.06); Surface roughness Ra = 3 μm (increasing the friction coefficient by 0.03); Corrected friction coefficient of the needle part = 0.3 + 0.06 + 0.03 = 0.39; 2. Wear condition of the shoulder part: Wear depth = 0.2 mm (increasing the friction coefficient by 0.04); Surface roughness Ra = 2 μm (increasing the friction coefficient by 0.02); Corrected friction coefficient of the shoulder part = 0.3 + 0.04 + 0.02 = 0.36; Heat calculation example: 1. Heat calculation of the needle part (divided into 3 regions): (1) Central region (radius 0 - 3 mm): Contact pressure = 12 kN (considering pressure concentration after wear); Heat flux density = 0.39 × 12 kN × 1000 rpm × 0.1047 = 489.996 W / cm²; Heat distribution coefficient = 0.6 (60% of the heat enters the tool); Region heat = 489.996 × π × 0.3² × 0.6 = 83.09 W; (2) Intermediate region (radius 3 - 6 mm): Contact pressure = 10 kN; Heat flux density = 0.39 × 10 kN × 1000 rpm × 0.1047 = 408.33 W / cm²; Heat distribution coefficient = 0.55; Regional heat = 408.33×π×(0.6² - 0.3²)×0.55 = 127.39W; (3)Peripheral region (radius 6 - 8mm): Contact pressure = 8kN; Heat flux density = 0.39×8kN×1000rpm×0.1047 = 326.664W / cm²; Heat distribution coefficient = 0.5; Regional heat = 326.664×π×(0.8² - 0.6²)×0.5 = 102.73W; Total heat of the needle part = 83.09 + 127.39 + 102.73 = 313.21W; 2. Shoulder heat calculation (divided into 2 regions): (1)Inner ring region (radius 8 - 16mm): Contact pressure = 9kN; Heat flux density = 0.36×9kN×1000rpm×0.1047 = 339.228W / cm²; Heat distribution coefficient = 0.45; Regional heat = 339.228×π×(1.6² - 0.8²)×0.45 = 543.93W; (2)Outer ring region (radius 16 - 24mm): Contact pressure = 7kN; Heat flux density = 0.36×7kN×1000rpm×0.1047 = 263.844W / cm²; Heat distribution coefficient = 0.4; Regional heat = 263.844×π×(2.4² - 1.6²)×0.4 = 633.85W; Total heat of the shoulder = 543.93 + 633.85 = 1177.78W.

[0067] Optionally, generally, the needle part friction heat data can be determined in the following ways, which are not limited herein: Obtain the material parameters of the needle part, where the material parameters include the thermal conductivity coefficient, specific heat capacity, and density; Based on the wear depth and wear area of the needle part, calculate the actual contact area between the needle part and the workpiece, and determine the dynamic friction coefficient of the needle part according to the surface roughness of the needle part; Substitute the material parameters, operating parameters, actual contact area, and dynamic friction coefficient into the needle part heat dissipation calculation formula to obtain the heat dissipation of the needle part per unit time.

[0068] The following uses a specific example to illustrate the calculation process of the needle part friction heat data. Assume the initial conditions are: Needle part material parameters (taking H13 steel as an example): Thermal conductivity coefficient (λ) = 28 W / (m·K), specific heat capacity (c) = 460 J / (kg·K), density (ρ) = 7800 kg / m³; Initial parameters of the needle part: Initial diameter = 8 mm, initial length = 6 mm, standard dynamic friction coefficient (μ0) = 0.3; Operating parameters of the needle part: Rotational speed (n) = 1200 rpm, axial pressure (F) = 12 kN, linear velocity (v) = πdn / 60 = π×0.008×1200 / 60 = 0.503 m / s; Detected wear parameters: Wear depth (h) = 0.25 mm, wear area (S) = 38 mm², surface roughness Ra = 2.5 μm.

[0069] The calculation process is as follows: (1) Correct the dynamic friction coefficient: Influence of wear depth: 0.25 mm / 0.1 mm × 0.02 = 0.05; Influence of surface roughness: 2.5 μm × 0.01 = 0.025; Corrected dynamic friction coefficient (μ) = 0.3 + 0.05 + 0.025 = 0.375; (2) Calculate the actual contact area: Initial contact area = π×(8 mm)² / 4 = 50.27 mm²; Actual contact area considering wear (A) = 50.27 + 38 = 88.27 mm² = 8.827×10⁻ 5 m²; (3) Heat dissipation formula for the needle part: Q = μ×F×v×k×A; Where, Q is the heat dissipation (W), μ is the corrected dynamic friction coefficient, F is the axial pressure (N), v is the linear velocity (m / s), k is the heat distribution coefficient (assumed to be 0.6, indicating 60% of the heat enters the tool), and A is the actual contact area coefficient (actual contact area / initial contact area); Substitute the values for calculation: Q = 0.375×12000×0.503×0.6×(88.27 / 50.27) = 2249.8 W; Therefore, the heat dissipation of the needle part per unit time is approximately 2250 W.

[0070] S209. Calculate the heat dissipation of the needle part and the heat dissipation of the shoulder per unit time based on the needle part friction heat data and the shoulder friction heat data.

[0071] Among them, the heat dissipation of the needle part refers to the heat that needs to be dissipated by the needle part per unit time, with the unit of joule per second; the heat dissipation of the shoulder part refers to the heat that needs to be dissipated by the shoulder part per unit time, with the unit of joule per second.

[0072] Specifically, the control system uses a multi-layer heat conduction model to calculate the heat dissipation, taking into account the thermal conductivity characteristics, geometric structure, and cooling channel distribution of the tool material. For the needle part, the control system divides it into a core area and a peripheral area, and calculates the heat transfer paths respectively; for the shoulder part, the control system adopts a radial zoning method, considering the heat dissipation conditions at different radius positions. The heat conduction equations are introduced in the calculation process, considering both steady-state and transient conditions. The control system also takes into account the variation of the thermal physical properties of the material with temperature, such as the thermal conductivity is adjusted by 5% for every 100 °C increase. The finally obtained heat dissipation data includes the distribution values and the total amounts of each area, and the accuracy can reach ±3%.

[0073] S210. Detect the working parameters of the cooling channels of the needle part and the shoulder part. The working parameters include the pressure difference between the inlet and outlet, the coolant temperature, and the cross-sectional area of the channel.

[0074] Among them, the pressure difference between the inlet and outlet refers to the pressure difference between the inlet and outlet of the cooling channel, with the unit of kilopascal; the coolant temperature refers to the temperature value of the cooling medium in the cooling channel, with the unit of degree Celsius; the cross-sectional area of the channel is used to represent the effective area for the coolant to flow through, with the unit of square millimeter.

[0075] Specifically, the control system synchronously collects the working parameters through a sensor network arranged at key positions of each cooling channel. High-precision pressure sensors are installed at the inlet and outlet, with a sampling frequency of 100 Hz and a measurement accuracy of 0.1 kPa; temperature sensors are arranged at equal intervals along the channel (no less than 3 for each channel) to monitor the coolant temperature distribution in real time; ultrasonic sensors are used to periodically detect the cross-sectional area of the channel to judge whether there is deposition or deformation. All sensor data are calibrated in real time and digitally filtered to ensure that the data reliability reaches 99.9%.

[0076] S211. Calculate the coolant flow rate of the needle part and the coolant flow rate of the shoulder part based on the heat dissipation of the needle part, the heat dissipation of the shoulder part, and the working parameters.

[0077] Specifically, the control system establishes a thermal-fluid coupling calculation model, combining the heat dissipation requirements with the channel characteristics. The calculation process is divided into three stages: In the first stage, the theoretically required flow rate is calculated based on the heat dissipation amount, considering the specific heat capacity of the coolant and the allowable temperature rise. In the second stage, a flow resistance equation is established based on the channel characteristics (pressure difference, cross-sectional area) to obtain the range of practically feasible flow rates. In the third stage, the optimal flow rate that meets the heat dissipation requirements and has the minimum system pressure loss is found through iterative calculation. The control system adopts a dynamic correction mechanism and updates the correction coefficient every 30 minutes according to the actual operation effect. At the same time, the control system compares the calculation results with the equipment limits to ensure operation within a safe range.

[0078] Optionally, generally, based on the needle part heat dissipation amount, shoulder part heat dissipation amount and working parameters, calculating the coolant flow rate of the needle part and the coolant flow rate of the shoulder part can be achieved in the following ways, which are not limited here: Calculate the reference coolant flow rate according to the pressure difference between the inlet and outlet and the cross-sectional area of the channel; Based on the needle part heat dissipation amount and the coolant temperature in the needle part cooling channel, calculate the minimum required cooling flow rate of the needle part; Based on the shoulder part heat dissipation amount and the coolant temperature in the shoulder part cooling channel, calculate the minimum required cooling flow rate of the shoulder part; When the reference coolant flow rate is less than the minimum required cooling flow rate of the needle part, increase the pump pressure of the needle part cooling channel to increase the pressure difference between the inlet and outlet; Substitute the increased pressure difference between the inlet and outlet into the preset flow rate calculation formula to obtain the coolant flow rate of the needle part; When the reference coolant flow rate is less than the minimum required cooling flow rate of the shoulder part, increase the pump pressure of the shoulder part cooling channel to increase the pressure difference between the inlet and outlet; Substitute the increased pressure difference between the inlet and outlet into the preset flow rate calculation formula to obtain the coolant flow rate of the shoulder part; When the reference coolant flow rate is greater than the minimum required cooling flow rate of the needle part, determine the minimum required cooling flow rate of the needle part as the coolant flow rate of the needle part; When the reference coolant flow rate is greater than the minimum required cooling flow rate of the shoulder part, determine the minimum required cooling flow rate of the shoulder part as the coolant flow rate of the shoulder part.

[0079] The following uses a specific example to illustrate the calculation process of the coolant flow rate: Initial conditions: 1. Heat dissipation data: Needle part heat dissipation amount = 2250 W; Shoulder part heat dissipation amount = 3800 W; 2. Coolant physical property parameters (taking water-based coolant as an example): Specific heat capacity (c) = 4200 J / (kg·K); Density (ρ) = 998 kg / m³; Allowable temperature rise (ΔT) = 15 °C; 3. Channel parameters: Cross-sectional area of the needle part channel (A1) = 28.3 mm² (φ6 mm); Cross-sectional area of the shoulder part channel (A2) = 50.3 mm² (φ8 mm); Initial inlet and outlet pressure difference (ΔP) = 0.2 MPa; Maximum allowable pressure difference = 0.8 MPa.

[0080] Calculation process: 1. Calculate the reference flow rate of the coolant: Use Bernoulli's equation: Q = Cd × A × √(2 × ΔP / ρ), where Cd is the flow coefficient (take 0.85); Reference flow rate of the needle part: Q1 = 0.85 × 28.3 × 10⁻ 6 × √(2 × 0.2 × 10 6 / 998) = 4.82 L / min; Reference flow rate of the shoulder part: Q2 = 0.85 × 50.3 × 10⁻ 6 × √(2 × 0.2 × 10 6 / 998) = 8.57 L / min; 2. Calculate the minimum required cooling flow rate: Q minimum = Q heat dissipation / (ρ × c × ΔT); Minimum flow rate of the needle part: Q1 minimum = 2250 / (998 × 4200 × 15) × 60000 = 6.43 L / min; Minimum flow rate of the shoulder part: Q2 minimum = 3800 / (998 × 4200 × 15) × 60000 = 10.85 L / min; 3. Flow rate adjustment calculation: Cooling channel of the needle part: Reference flow rate (4.82 L / min) < Required minimum flow rate (6.43 L / min), need to increase the pressure difference; Calculation of the new pressure difference: ΔP1 new = (6.43 / 4.82)² × 0.2 = 0.357 MPa, final flow rate of the needle part = 6.43 L / min; Cooling channel of the shoulder part: Reference flow rate (8.57 L / min) < Required minimum flow rate (10.85 L / min), need to increase the pressure difference; Calculation of the new pressure difference: ΔP2 new = (10.85 / 8.57)² × 0.2 = 0.320 MPa, final flow rate of the shoulder part = 10.85 L / min; 4. Verification and adjustment: Check whether the new pressure difference is within the allowable range: New pressure difference of the needle part 0.357 MPa < Maximum allowable pressure difference 0.8 MPa (satisfied); New pressure difference of the shoulder part 0.320 MPa < Maximum allowable pressure difference 0.8 MPa (satisfied); System correction: Check the actual cooling effect after 30 minutes. If the temperature control effect is not ideal, adjust the correction factor. Assuming the cooling effect is slightly low, the correction factor is taken as 1.1. After correction, the flow rates are as follows: Needle part: 6.43 × 1.1 = 7.07 L / min, Shoulder part: 10.85 × 1.1 = 11.94 L / min; 5. Final output parameters: 1. Needle part cooling channel: Flow rate: 7.07 L / min, Working pressure difference: 0.432 MPa; 2. Shoulder part cooling channel: Flow rate: 11.94 L / min, Working pressure difference: 0.387 MPa.

[0081] S212. Input the needle part temperature data, shoulder part temperature data, needle part coolant flow rate, and shoulder part coolant flow rate into the temperature prediction model to obtain the predicted needle part temperature and predicted shoulder part temperature within a preset future time period. The needle part coolant flow rate refers to the coolant flow rate in the current needle part cooling channel, and the shoulder part coolant flow rate refers to the coolant flow rate in the current shoulder part cooling channel.

[0082] Specifically, refer to step S102, which will not be elaborated here.

[0083] S213. Obtain the operating parameters of the stirring head. The operating parameters include the stirring head rotation speed, axial pressure, and stirring depth.

[0084] Among them, the operating parameters represent the key process variables describing the working state of the stirring head; the stirring head rotation speed refers to the angular velocity of the tool rotating around its own axis, with the unit of revolutions per minute; the axial pressure is used to represent the pressure exerted by the stirring head in the vertical direction, with the unit of kilonewtons; the stirring depth represents the distance that the needle part of the stirring head inserts into the workpiece, with the unit of millimeters.

[0085] Specifically, the control system collects the operating parameters in real time through multiple sensor systems working in coordination: The stirring head rotation speed is measured by a high-precision Hall sensor, with a sampling frequency of 1000 Hz and an accuracy of ±1 rpm; the axial pressure is measured by a strain gauge pressure sensor, with a sampling frequency of 500 Hz and an accuracy of ±0.1 kN; the stirring depth is measured by a displacement sensor, with a sampling frequency of 100 Hz and an accuracy of ±0.01 mm. The control system performs real-time filtering and averaging on the collected data to eliminate the influence of instantaneous fluctuations. At the same time, the control system records the change trend of the parameters to judge the stability of the process.

[0086] S214. Input the operating parameters into the first temperature formula and the second temperature formula respectively to obtain the preset needle part target temperature and the preset shoulder part target temperature.

[0087] Among them, the first temperature formula represents a mathematical equation for calculating the preset target temperature of the needle part; the second temperature formula refers to a mathematical equation for calculating the preset target temperature of the shoulder part; the preset target temperature of the needle part is used to represent the ideal operating temperature of the needle part; the preset target temperature of the shoulder part represents the ideal operating temperature of the shoulder part. The first temperature formula is: Tn = T0 + k1×P - k2×R + k3×D; the second temperature formula is: Ts = T0 + k4×P - k5×R - k6×D; where, Tn is the preset target temperature of the needle part, Ts is the preset target temperature of the shoulder part, T0 is the preset reference temperature, P is the axial pressure, R is the rotational speed of the stirring head, D is the stirring depth, k1 is the pressure-temperature coefficient of the needle part, k2 is the rotational speed-temperature coefficient of the needle part, k3 is the depth-temperature coefficient of the needle part, k4 is the pressure-temperature coefficient of the shoulder part, k5 is the rotational speed-temperature coefficient of the shoulder part, and k6 is the depth-temperature coefficient of the shoulder part.

[0088] Specifically, the control system substitutes the collected operating parameters into the first temperature formula and the second temperature formula. The reference temperature T0 is usually set to the ambient temperature plus 100°C. Each temperature coefficient is calibrated through a large number of experiments: k1 (pressure-temperature coefficient of the needle part) ≈ 0.5°C / kN, k2 (rotational speed-temperature coefficient of the needle part) ≈ 0.02°C / rpm, k3 (depth-temperature coefficient of the needle part) ≈ 2°C / mm, k4 (pressure-temperature coefficient of the shoulder part) ≈ 0.3°C / kN, k5 (rotational speed-temperature coefficient of the shoulder part) ≈ 0.015°C / rpm, k6 (depth-temperature coefficient of the shoulder part) ≈ 1°C / mm. The control system updates the calculation result every 0.1 second and compares the calculated target temperature with the process allowable range to ensure that the temperature setting value is within the safe range.

[0089] S215. When the deviation between the predicted temperature of the needle part and the preset target temperature of the needle part exceeds the first temperature threshold and / or the deviation between the predicted temperature of the shoulder part and the preset target temperature of the shoulder part exceeds the second temperature threshold, calculate the target flow rate of the needle part and / or the target flow rate of the shoulder part.

[0090] Specifically, reference can be made to step S103, which will not be elaborated here.

[0091] S216. Adjust the coolant flow rate of the needle cooling channel and / or the shoulder cooling channel to reach the target flow rate of the needle part and / or the target flow rate of the shoulder part.

[0092] Specifically, reference can be made to step S104, which will not be elaborated here.

[0093] The following introduces the stirring head in the embodiments of the present application. Please refer to Figure 3 , which is a schematic structural diagram of the stirring head in the embodiments of the present application.

[0094] The following describes the control system in the embodiments of the present invention application from the perspective of hardware processing. Please refer to Figure 4, which is a schematic structural diagram of an entity device in the control system according to an embodiment of the present application.

[0095] It should be noted that Figure 4 the structure of the control system shown is only an example and should not impose any limitations on the functions and usage scope of the embodiments of the present invention.

[0096] As Figure 4 shown, the control system includes a CPU 401, which can perform various appropriate actions and processes according to the program stored in the read-only memory ROM 402 or the program loaded from the storage section 408 into the random access memory RAM 403, such as executing the method described in the above embodiments. In the RAM 403, various programs and data required for system operation are also stored. The CPU 401, ROM 402, and RAM 403 are connected to each other via a bus 404. The I / O interface 405 is also connected to the bus 404.

[0097] The following components are connected to the I / O interface 405: an input section 406 including an audio input device, a button switch, etc.; an output section 407 including a liquid crystal display (LCD), an audio output device, an indicator light, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 409 performs communication processing via a network such as the Internet. The drive 410 is also connected to the I / O interface 405 as needed. A removable medium 411, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 410 as needed so that the computer program read from it can be installed into the storage section 408 as needed.

[0098] Particularly, according to the embodiments of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments of the present invention include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication section 409 and / or installed from the removable medium 411. When the computer program is executed by the CPU 401, various functions defined in the present invention are executed.

[0099] It should be noted that specific examples of computer-readable storage media may include, but are not limited to: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fibers, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium that contains or stores a program, and this program can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0100] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present invention. Among them, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above-mentioned module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the accompanying drawings.

[0101] Specifically, the control system of this embodiment includes a processor and a memory. A computer program is stored on the memory. When the computer program is executed by the processor, the stirring head temperature control method provided in the above embodiment is implemented.

[0102] On the other hand, the present invention also provides a computer-readable storage medium, which may be included in the control system described in the above embodiment; or it may exist separately and not be assembled into the control system. The above storage medium carries one or more computer programs. When the above one or more computer programs are executed by a processor of the control system, the control system implements the stirring head temperature control method provided in the above embodiment.

[0103] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present application.

[0104] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by relevant hardware instructed by a computer program. This program can be stored in a computer-readable storage medium. When this program is executed, it can include the processes of the above method embodiments. The aforementioned storage medium includes various media that can store program codes, such as ROM, random access memory (RAM), magnetic disks, or optical discs.

Claims

1. A method for controlling the temperature of a stirring head, characterized in that, Applied to a control system, the method includes: Collecting the needle part temperature data and the shoulder part temperature data of the stirring head, where the needle part temperature data includes the current temperature of the needle part and the temperature change rate of the needle part, and the shoulder part temperature data includes the current temperature of the shoulder part and the temperature change rate of the shoulder part; Inputting the needle part temperature data, the shoulder part temperature data, the coolant flow rate of the needle part, and the coolant flow rate of the shoulder part into a temperature prediction model to obtain the predicted temperature of the needle part and the predicted temperature of the shoulder part within a future preset time period. The coolant flow rate of the needle part refers to the coolant flow rate in the current needle part cooling channel, and the coolant flow rate of the shoulder part refers to the coolant flow rate in the current shoulder part cooling channel; When the deviation between the predicted temperature of the needle part and the preset target temperature of the needle part exceeds the first temperature threshold and / or the deviation between the predicted temperature of the shoulder part and the preset target temperature of the shoulder part exceeds the second temperature threshold, calculate the target flow rate of the needle part and / or the target flow rate of the shoulder part; Adjust the coolant flow rate of the needle part cooling channel and / or the shoulder part cooling channel to reach the target flow rate of the needle part and / or the target flow rate of the shoulder part.

2. The method according to claim 1, wherein After the step of collecting the needle part temperature data and the shoulder part temperature data of the stirring head, where the needle part temperature data includes the current temperature of the needle part and the temperature change rate of the needle part, and the shoulder part temperature data includes the current temperature of the shoulder part and the temperature change rate of the shoulder part, the method further includes: If the temperature change rate of the needle part and / or the temperature change rate of the shoulder part exceeds the preset rate threshold, adjust the coolant flow rate of the needle part cooling channel to the preset maximum flow rate of the needle part and / or adjust the coolant flow rate of the shoulder part cooling channel to the preset maximum flow rate of the shoulder part, and reduce the rotation speed of the stirring head to the preset safe rotation speed; After a preset time period, if the temperature change rate of the needle part and / or the temperature change rate of the shoulder part still exceeds the preset rate threshold, control the stirring head to stop.

3. The method according to claim 1, wherein Before the step of calculating the target flow rate of the needle part and / or the target flow rate of the shoulder part when the deviation between the predicted temperature of the needle part and the preset target temperature of the needle part exceeds the first temperature threshold and / or the deviation between the predicted temperature of the shoulder part and the preset target temperature of the shoulder part exceeds the second temperature threshold, the method further includes: Obtaining the operating parameters of the stirring head, where the operating parameters include the rotation speed of the stirring head, the axial pressure, and the stirring depth; Inputting the operating parameters into the first temperature formula and the second temperature formula respectively to obtain the preset target temperature of the needle part and the preset target temperature of the shoulder part; The first temperature formula is: Tn = T0 + k1×P - k2×R + k3×D; The second temperature formula is: Ts = T0 + k4×P - k5×R - k6×D; Where, Tn is the preset target temperature of the needle part, Ts is the preset target temperature of the shoulder part, T0 is the preset reference temperature, P is the axial pressure, R is the rotation speed of the stirring head, D is the stirring depth, k1 is the needle part pressure temperature coefficient, k2 is the needle part rotation speed temperature coefficient, k3 is the needle part depth temperature coefficient, k4 is the shoulder part pressure temperature coefficient, k5 is the shoulder part rotation speed temperature coefficient, and k6 is the shoulder part depth temperature coefficient.

4. The method according to claim 1, wherein Before the step of inputting the needle part temperature data, the shoulder part temperature data, the needle part coolant flow rate, and the shoulder part coolant flow rate into a temperature prediction model to obtain the predicted needle part temperature and the predicted shoulder part temperature within a preset future time period, where the needle part coolant flow rate refers to the coolant flow rate in the current needle part cooling channel and the shoulder part coolant flow rate refers to the coolant flow rate in the current shoulder part cooling channel, the method further includes: Obtain the needle part contour data and the shoulder part contour data of the stirring head to determine wear characteristic parameters, where the wear characteristic parameters include the wear depth, wear area, and surface roughness of the needle part and the shoulder part; Based on the wear characteristic parameters, determine the needle part frictional heat data and the shoulder part frictional heat data; According to the needle part frictional heat data and the shoulder part frictional heat data, calculate the heat dissipation amount of the needle part and the heat dissipation amount of the shoulder part per unit time; Detect the working parameters of the needle part cooling channel and the shoulder part cooling channel, where the working parameters include the inlet and outlet pressure difference, coolant temperature, and channel cross-sectional area; Based on the heat dissipation amount of the needle part, the heat dissipation amount of the shoulder part, and the working parameters, calculate the needle part coolant flow rate and the shoulder part coolant flow rate.

5. The method according to claim 4, characterized in that The determining the needle part frictional heat data specifically includes: Obtain the material parameters of the needle part, where the material parameters include the thermal conductivity coefficient, specific heat capacity, and density; Based on the wear depth and wear area of the needle part, calculate the actual contact area between the needle part and the workpiece, and determine the dynamic friction coefficient of the needle part according to the surface roughness of the needle part; Substitute the material parameters, operating parameters, the actual contact area, and the dynamic friction coefficient into the needle part heat dissipation calculation formula to obtain the heat dissipation amount of the needle part per unit time.

6. The method according to claim 4, characterized in that, The calculating the needle part coolant flow rate and the shoulder part coolant flow rate based on the heat dissipation amount of the needle part, the heat dissipation amount of the shoulder part, and the working parameters specifically includes: Calculate the coolant reference flow rate according to the inlet and outlet pressure difference and the channel cross-sectional area; Based on the heat dissipation amount of the needle part and the coolant temperature of the needle part cooling channel, calculate the minimum cooling flow rate required for the needle part; Based on the heat dissipation amount of the shoulder part and the coolant temperature of the shoulder part cooling channel, calculate the minimum cooling flow rate required for the shoulder part; When the coolant reference flow rate is less than the minimum cooling flow rate required for the needle part, increase the pump pressure of the needle part cooling channel to increase the inlet and outlet pressure difference; substitute the increased inlet and outlet pressure difference into the preset flow rate calculation formula to obtain the needle part coolant flow rate; When the coolant reference flow rate is less than the minimum cooling flow rate required for the shoulder part, increase the pump pressure of the shoulder part cooling channel to increase the inlet and outlet pressure difference; substitute the increased inlet and outlet pressure difference into the preset flow rate calculation formula to obtain the shoulder part coolant flow rate; When the coolant reference flow rate is greater than the minimum cooling flow rate required for the needle part, determine the minimum cooling flow rate required for the needle part as the needle part coolant flow rate; When the coolant reference flow rate is greater than the minimum cooling flow rate required for the shoulder part, determine the minimum cooling flow rate required for the shoulder part as the shoulder part coolant flow rate.

7. The method according to claim 1, characterized in that, Before the step of collecting the needle part temperature data and the shoulder part temperature data of the stirring head, the method further includes: Obtain the ambient temperature and ambient humidity; Determine whether the ambient temperature and the ambient humidity meet the working conditions of friction stir welding; If they are met, start the stirring head; If they are not met, adjust the ambient temperature and the ambient humidity to meet the working conditions of friction stir welding.

8. A control system, characterized in that, The control system includes: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code includes computer instructions, and the one or more processors call the computer instructions to enable the control system to execute the method according to any one of claims 1-7.

9. A computer-readable storage medium, comprising instructions, characterized in that, When the instructions run on the control system, enable the control system to execute the method according to any one of claims 1-7.

10. A computer program product, characterized in that, When the computer program product runs on the control system, enable the control system to execute the method according to any one of claims 1-7.

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