Copper pipe straightening dynamic compensation method and system

Abstract

The invention provides a dynamic compensation method and system for copper pipe straightening, which are applied to the technical field of copper pipe straightening, and dynamically calculate and adjust the position of a straightening roll by sensing the center position coordinate and the section torsion angle of a copper pipe in real time and based on a correlation model of attitude and mechanical action so as to compensate the mechanical action deviation caused by attitude change. The problems that in the high-speed straightening process of the copper pipe, due to posture changes such as dynamic torsion, straightening mechanical action deviation is caused, and the straightening precision is affected are solved, and the advantage of improving the straightening precision is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of copper tube straightening, and particularly to a dynamic compensation method and system for copper tube straightening. Background Art

[0002] As a common metal material, after undergoing previous processing operations such as stretching and rolling, copper tubes usually undergo a certain degree of bending or deformation, resulting in their straightness not meeting the requirements of subsequent processing or use. In order to obtain copper tubes with high straightness, precise straightening treatment is required.

[0003] However, during the copper tube straightening process, in addition to bearing the bending moment applied by the straightening rolls, when passing through a multi-roll straightening machine at high speed, the copper tube may also be subjected to other complex dynamic mechanical actions, such that during the high-speed movement of the copper tube, in addition to bending deformation, it may also generate dynamic torsion along its own axis. This torsional movement is not constant, but dynamically fluctuates with time, the position of the copper tube inside the straightening machine, and specific working conditions.

[0004] The dynamic torsion of the copper tube directly affects its actual attitude in the straightening roll gap and the contact state with the straightening rolls, which will cause the effective component of the actually applied bending moment to change when there is dynamic torsion in the copper tube for the roll position settings originally mainly used to generate bending moment, and at the same time, additional and unexpected torques may be generated.

[0005] This means that even if the straightening system can compensate for the bending springback of the copper tube to a certain extent through real-time measurement and calculation, due to the failure to effectively handle the influence brought by the dynamic torsion of the copper tube, the actual mechanical action applied by the straightening rolls may still deviate from the expectation. This deviation may cause residual bending or residual torsion in the final shape of the copper tube, thus affecting the final straightness accuracy.

[0006] Therefore, during the high-speed and high-precision copper tube straightening process, how to on-line and real-time sense the dynamic torsion of the copper tube as a slender member along its own axis and its real-time influence on the mechanical action applied by the straightening rolls, and based on this, perform precise compensation to ensure the straightening effect and achieve extremely high straightness accuracy.

[0007] In view of the above problems of the prior art, there is an urgent need for improvement. Summary of the Invention

[0008] In view of the deficiencies of the above prior art, the present application provides a dynamic compensation method and system for copper tube straightening, which has the advantages of being able to real-time sense the dynamic attitude changes of the copper tube, including the central position coordinates and the cross-sectional torsion angle, and based on this, dynamically adjust the position of the straightening rolls, thereby compensating for the deviation of the mechanical action caused by the attitude change and improving the straightening accuracy.

[0009] First aspect, a dynamic compensation method for straightening copper tubes, which is used for a straightening machine to straighten copper tubes. The method includes the following steps: S1: Obtain the spatial position coordinates of each laser displacement sensor inside the straightening machine, and the distance data of each point on the cross-section of the copper tube collected by the laser displacement sensor in real time; S2: According to the distance data and the spatial position coordinates of each laser displacement sensor, calculate the central position coordinates and the cross-section torsion angle of the copper tube cross-section in real time; S3: According to the central position coordinates and the cross-section torsion angle, combined with a preset attitude-mechanical action correlation model, calculate the compensation adjustment amount of the straightening roll; S4: According to the compensation adjustment amount, drive the straightening roll actuator to adjust the position of the straightening roll to compensate for the deviation of the straightening mechanical action caused by the change of the copper tube attitude.

[0010] A dynamic compensation method for straightening copper tubes proposed in this application can, by perceiving the central position coordinates and the cross-section torsion angle of the copper tube in real time and based on the correlation model between the attitude and the mechanical action, dynamically calculate and adjust the position of the straightening roll to compensate for the deviation of the mechanical action caused by the attitude change. It solves the problem that the deviation of the straightening mechanical action caused by attitude changes such as dynamic torsion during the high-speed straightening of copper tubes affects the straightening accuracy, and has the advantage of improving the straightening accuracy.

[0011] Further, step S1 includes: S11: Calibrate each laser displacement sensor to obtain the spatial position coordinates of each laser displacement sensor in the straightening machine coordinate system; S12: Set the data acquisition frequency of the laser displacement sensor, and dynamically adjust the data acquisition frequency according to the movement speed of the copper tube to ensure that the distance between adjacent two data acquisition points is less than a preset threshold value in the movement direction of the copper tube; S13: Start the laser displacement sensor, and collect the distance data of each point on the cross-section of the copper tube in real time according to the data acquisition frequency.

[0012] A dynamic compensation method for straightening copper tubes proposed in this application provides specific technical means to ensure accurate, reliable and real-time data acquisition by refining the process of obtaining the spatial position coordinates and the distance data, and provides a high-quality data basis for subsequent accurate calculation of the copper tube attitude and dynamic compensation.

[0013] Further, step S13 includes: S131: Collect the first distance data of each point on the cross-section of the copper tube in real time; S132: Use the median filtering algorithm to filter the first distance data to obtain the filtered second distance data; S133: Calculate the standard deviation of the second distance data. If the absolute value of the difference between the first distance data and the second distance data is greater than N times the standard deviation, it is determined as an outlier and excluded to obtain the distance data, where N is a preset outlier coefficient.

[0014] A dynamic compensation method for copper pipe straightening proposed in this application, by collecting the first distance data and the second distance data, and obtaining the required distance data after filtering processing, solves the problems of possible noise and outliers in the first distance data, improves the data quality, and thus enhances the accuracy of subsequent copper pipe attitude calculation.

[0015] Further, step S2 includes: S21: Construct a copper pipe cross-section coordinate system, with the plane where the laser displacement sensor is located as the XY plane, the axial direction of the copper pipe as the Z axis, and the origin located at the origin of the straightening machine coordinate system. S22: According to the spatial position coordinates, combined with the coordinate transformation matrix, transform the spatial position coordinates of each laser displacement sensor to the copper pipe cross-section coordinate system to obtain the plane coordinates of each laser displacement sensor in the copper pipe cross-section coordinate system. S23: According to the distance data and the plane coordinates of each laser displacement sensor, use the least squares method to fit the copper pipe cross-section circle to obtain the center coordinates and radius of the fitted circle. S24: Use the center coordinates as the center position coordinates of the copper pipe cross-section, and calculate the deviation between the distance data and the theoretical distance on the corresponding fitted circle. S25: According to the deviation, use the gradient descent method to iteratively optimize the torsion angle of the copper pipe cross-section until the sum of the squares of the deviations is less than a preset threshold, and use the final torsion angle as the cross-section torsion angle of the copper pipe cross-section.

[0016] A dynamic compensation method for copper pipe straightening proposed in this application, by according to the spatial position coordinates of the laser displacement sensor and the collected distance data, calculates the center position coordinates and cross-section torsion angle of the copper pipe cross-section in real time and accurately. This solves the problem of how to extract accurate attitude information from sensor data with noise in the case of high-speed movement and dynamic torsion of the copper pipe, and provides reliable basic data for subsequent straightening compensation.

[0017] Further, step S22 includes: S221: Construct a coordinate transformation matrix, where the coordinate transformation matrix includes a rotation matrix and a translation vector. S222: Represent the spatial position coordinates of each laser displacement sensor as homogeneous coordinates, and multiply the coordinate transformation matrix by the homogeneous coordinates to obtain the cross-section homogeneous coordinates of each laser displacement sensor in the copper pipe cross-section coordinate system. S223: Extract the first two components of the homogeneous coordinates of the cross-section as the planar coordinates of each laser displacement sensor in the copper tube cross-section coordinate system.

[0018] Further, step S23 includes: S231: Set the initial center coordinates and initial radius of the initial fitting circle, and set the maximum number of iterations. S232: According to the distance data and the planar coordinates of each laser displacement sensor, calculate the initial distance deviation of each laser displacement sensor from the initial fitting circle, and calculate the initial sum of squares of all the initial distance deviations. S233: Determine whether the current initial sum of squares is less than the initial sum of squares of the previous iteration. If so, accept the current adjustment result, update the number of iterations, and return to S232 to continue the next iteration; otherwise, reduce the step size of the gradient descent method, readjust the initial center coordinates and initial radius. If the calculated initial sum of squares after adjustment is still not less than the initial sum of squares of the previous iteration, and the step size is less than the preset threshold, stop the iteration and output the center coordinates and radius of the fitting circle corresponding to the minimum initial sum of squares during the iteration; otherwise, execute S234. S234: Determine whether the current number of iterations has reached the maximum number of iterations. If so, output the center coordinates and radius of the current fitting circle after iteration; otherwise, return to S232.

[0019] Further, step S3 includes: S31: Take the center position coordinates and cross-section torsion angle of the copper tube cross-section as inputs, and take the bending moment and torque applied to the copper tube by the straightening rolls as outputs, establish the functional relationship between the center position coordinates, cross-section torsion angle and bending moment, torque, and use this functional relationship as the attitude-mechanical action correlation model. S32: Set the target attitude of the copper tube as the ideal center position coordinates and zero torsion angle. According to the target attitude, combined with the attitude-mechanical action correlation model, calculate the target straightening mechanical action. S33: According to the center position coordinates and cross-section torsion angle of the current copper tube cross-section, combined with the attitude-mechanical action correlation model, calculate the actual straightening mechanical action in the current attitude, and calculate the mechanical deviation between the target straightening mechanical action and the actual straightening mechanical action. S34: Calculate the compensation adjustment amount of each straightening roll according to the mechanical deviation.

[0020] Further, step S34 includes: S341: Establish a mapping relationship between the straightening roll adjustment amount and the mechanical deviation. This mapping relationship is obtained through experiments or simulations and characterizes the relationship between the bending moment and torque applied by the straightening rolls to the copper tube and the target mechanical action at different straightening roll positions. S342: Calculate the compensation adjustment amount of each straightening roll based on the mechanical deviation and in combination with the mapping relationship.

[0021] Further, step S4 includes: S41: Obtain the actual position parameters of the straightening roll actuator in real time. S42: Compare the compensation adjustment amount with the actual position parameters to obtain a position deviation, and determine whether the position deviation exceeds a preset deviation threshold. S43: If the position deviation exceeds the preset deviation threshold, drive the straightening roll actuator to adjust the position of the straightening roll until the position deviation is less than or equal to the preset deviation threshold to compensate for the deviation of the straightening mechanical action caused by the change in the posture of the copper tube.

[0022] In a second aspect, a copper tube straightening dynamic compensation system is characterized in that it is used to implement the method described in any one of the above. The system includes: An acquisition module: acquire the spatial position coordinates of each laser displacement sensor inside the straightening machine and the distance data of each point on the cross-section of the copper tube collected by the laser displacement sensor in real time. A calculation module: calculate the central position coordinates and the cross-section torsion angle of the copper tube cross-section in real time according to the distance data and the spatial position coordinates of each laser displacement sensor. A computing module: calculate the compensation adjustment amount of the straightening roll according to the central position coordinates and the cross-section torsion angle in combination with a preset attitude-mechanical action correlation model. A compensation module: drive the straightening roll actuator to adjust the position of the straightening roll according to the compensation adjustment amount to compensate for the deviation of the straightening mechanical action caused by the change in the posture of the copper tube.

[0023] Beneficial effects: A copper tube straightening dynamic compensation method and system proposed in this application can dynamically calculate and adjust the position of the straightening roll by real-time sensing the central position coordinates and the cross-section torsion angle of the copper tube and based on the correlation model between the attitude and the mechanical action, so as to compensate for the deviation of the mechanical action caused by the attitude change. It solves the problem that the deviation of the straightening mechanical action caused by the attitude changes such as dynamic torsion during the high-speed straightening of the copper tube affects the straightening accuracy, and has the advantage of improving the straightening accuracy. Description of the Drawings

[0024] Figure 1 It is a flowchart of a copper tube straightening dynamic compensation method proposed in this application.

[0025] Figure 2 This is a structural diagram of a dynamic compensation system for copper pipe straightening proposed in this application.

[0026] Figure 3 This is an architecture diagram of a dynamic compensation system for copper pipe straightening proposed in this application.

[0027] Label description: 201, acquisition module; 202, calculation module; 203, computing module; 204, compensation module. Detailed implementation manners

[0028] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Usually, the components of the embodiments of this application described and marked in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application required to be protected, but only represents the selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative efforts belong to the scope of protection of this application.

[0029] It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0030] Please refer to Figure 1 , a dynamic compensation method for copper pipe straightening, used for a straightening machine to straighten copper pipes. The method includes the steps of: S1: Obtain the spatial position coordinates of each laser displacement sensor inside the straightening machine, and the distance data of each point on the cross-section of the copper pipe collected by the laser displacement sensor in real time; S2: According to the distance data and the spatial position coordinates of each laser displacement sensor, calculate and obtain the central position coordinates and cross-section torsion angle of the copper pipe cross-section in real time; S3: According to the central position coordinates and the cross-section torsion angle, combined with a preset attitude-mechanical action correlation model, calculate the compensation adjustment amount of the straightening rolls; S4: According to the compensation adjustment amount, drive the straightening roll actuator to adjust the position of the straightening rolls to compensate for the deviation of the straightening mechanical action caused by the change in the attitude of the copper pipe.

[0031] Among them, the laser displacement sensors can be arranged at intervals along the copper pipe conveying direction, and are mainly used to non-contactedly obtain the distance information of each point on the surface of the copper pipe.

[0032] The spatial position coordinates refer to the three-dimensional position information of the laser displacement sensor in the fixed coordinate system of the straightening machine.

[0033] The cross-section torsion angle refers to the rotation angle of the copper tube cross-section around the copper tube axis relative to a certain reference direction; the attitude-mechanical action correlation model refers to a mathematical model or mapping relationship that describes the relationship between the copper tube cross-section attitude and the mechanical action exerted by the straightening rolls on the copper tube.

[0034] The compensation adjustment amount refers to the correction amount of the position or angle of the straightening roll calculated according to the change of the copper tube attitude.

[0035] The straightening roll actuator refers to a device that drives the straightening roll to adjust its position or angle, which can be implemented by an electric servo system, a hydraulic servo system or a pneumatic actuator. For example, a lead screw mechanism driven by a servo motor, which is mainly used to accurately execute the compensation adjustment action of the straightening roll; the deviation of the straightening mechanical action refers to the difference between the actual mechanical action exerted by the straightening roll on the copper tube and the target mechanical action, which is mainly caused by the change of the contact state between the straightening roll and the copper tube due to the change of the copper tube attitude and needs to be eliminated by compensation.

[0036] Specifically, first, obtain the spatial position coordinates of the laser displacement sensor inside the straightening machine, which provide a fixed reference for the sensor in the machine coordinate system. At the same time, the laser displacement sensor real-time collects the distance data of each point on the copper tube cross-section, and these data reflect the geometric contour of the copper tube surface.

[0037] Next, based on the collected distance data and the spatial position coordinates of each laser displacement sensor, the method calculates in real time the central position coordinates of the copper tube cross-section in space and the cross-section torsion angle along its own axis. This step converts the original distance information into the accurate attitude information of the copper tube at the current moment.

[0038] Then, the method takes the calculated central position coordinates and cross-section torsion angle of the copper tube cross-section as inputs, and combines with a preset attitude-mechanical action correlation model. This model establishes the relationship between the copper tube attitude and the mechanical action exerted by the straightening rolls. Through model calculation, the compensation adjustment amount that the straightening roll needs to perform can be obtained under the current copper tube attitude to ensure that the exerted mechanical action meets the expectations. Finally, the method drives the corresponding straightening roll actuator to adjust the position of the straightening roll according to the calculated compensation adjustment amount of the straightening roll. Through this dynamic position adjustment, the deviation of the straightening mechanical action caused by the change of the copper tube attitude, especially dynamic torsion, is compensated in real time, thereby maintaining the stability and effectiveness of the straightening process.

[0039] As a preferred embodiment, the solution of the present application is specifically implemented as follows: Multiple measurement stations can be set inside the straightening machine along the movement direction of the copper tube. Each measurement station is equipped with one or more laser displacement sensors. If multiple sensors are configured, the multiple laser displacement sensors at the same measurement station are arranged around the circumference of the copper tube. The spatial position coordinates of these laser displacement sensors can be obtained through pre-precise calibration and stored in the system.

[0040] During the straightening process, these laser displacement sensors collect distance data of each point on the surface of the copper tube in real time at a set frequency. After the system receives the distance data, combined with the spatial position coordinates of the sensors, geometric algorithms and numerical calculation methods are used. For example, the least squares method is used to fit the cross-sectional circle of the copper tube to determine the central position, and the cross-sectional torsion angle is calculated based on the change in the distribution of cross-sectional points or the position of characteristic points. The actual calculation is carried out continuously to track the dynamic posture of the copper tube.

[0041] The calculated central position coordinates and cross-sectional torsion angle are input into a pre-established posture-mechanical action correlation model. This model can be a mapping relationship obtained through training with a large amount of experimental data. What the model outputs is the position or angle adjustment amount of each straightening roll required to compensate for the current posture change.

[0042] Finally, according to the calculated compensation adjustment amount, the control system sends instructions to the actuators of each straightening roll. The actuators, such as precision lead screws or hydraulic cylinders driven by servo motors, accurately move or rotate the straightening rolls to new positions. This adjustment process is carried out dynamically and is synchronized with the real-time change of the copper tube posture, so as to achieve real-time compensation for the deviation of the straightening mechanical action.

[0043] Through the above solution, the present application can perceive the dynamic posture of the copper tube during the straightening process online and in real time, including its central position and torsion along the axis. Based on this real-time posture information, combined with the correlation model between posture and mechanical action, the adjustment amount of the straightening roll required to compensate for the deviation of the straightening mechanical action can be accurately calculated. By driving the actuator to dynamically adjust the position of the straightening roll, effective compensation for the deviation of the mechanical action caused by the change of the copper tube posture is achieved. This significantly improves the stability of the straightening process and the adaptability to the dynamic behavior of the copper tube, thus ensuring the straightening effect and helping to obtain extremely high straightness accuracy of the copper tube.

[0044] Further, step S1 includes: S11: Calibrate each laser displacement sensor to obtain the spatial position coordinates of each laser displacement sensor in the coordinate system of the straightening machine; S12: Set the data acquisition frequency of the laser displacement sensor, and dynamically adjust the data acquisition frequency according to the movement speed of the copper tube to ensure that the distance between adjacent two data acquisition points is less than a preset threshold in the movement direction of the copper tube; S13: Activate the laser displacement sensor and, according to the data acquisition frequency, collect the distance data of each point on the cross-section of the copper tube in real time.

[0045] Among them, calibrating each laser displacement sensor means determining the precise three-dimensional position and attitude of each laser displacement sensor in a unified reference coordinate system (straightening machine coordinate system) inside the straightening machine through specific measurement methods or equipment. It can be achieved by measuring based on known reference points, using a high-precision measuring arm, or through a vision measurement system.

[0046] Obtaining the spatial position coordinates of each laser displacement sensor in the straightening machine coordinate system means recording the position and attitude information obtained during the calibration process in the form of coordinates in the straightening machine coordinate system.

[0047] In one embodiment, the data acquisition can be implemented in the following way: After the straightening machine is installed, use a high-precision three-coordinate measuring instrument to calibrate the spatial positions of multiple laser displacement sensors installed inside the straightening machine. The probe of the measuring instrument successively contacts or aims at specific reference points of each sensor, records its three-dimensional coordinates and attitude information in the straightening machine coordinate system, and stores this information in the memory of the straightening machine control system as the spatial position coordinates of the sensor.

[0048] During the operation of the straightening machine, the axial movement speed of the copper tube is detected in real time through an encoder or a speed sensor installed at the feeding end of the copper tube. The control system calculates the current required data acquisition frequency according to this real-time speed value and in combination with a preset maximum distance threshold between adjacent data points (for example, set as a certain proportion of the copper tube diameter). For example, if the copper tube speed increases, the acquisition frequency is correspondingly increased to ensure that the number of data points per unit length does not decrease. Then, the control system sends a start command to each laser displacement sensor to make it start working. The sensor continuously measures the distance to the surface of the copper tube according to the dynamically adjusted acquisition frequency calculated and set by the control system, and transmits these distance data to the data processing unit in real time through industrial Ethernet or other high-speed communication interfaces for subsequent processing.

[0049] Further, step S13 includes: S131: Collect the first distance data of each point on the cross-section of the copper tube in real time; S132: Use the median filtering algorithm to filter the first distance data to obtain the filtered second distance data; S133: Calculate the standard deviation of the second distance data. If the absolute value of the difference between the first distance data and the second distance data is greater than N times the standard deviation, it is determined as an outlier and excluded to obtain the distance data; where N is a preset outlier coefficient.

[0050] Specifically, the method first collects the original distance data of each point on the cross-section of the copper tube in real time, which is called the first distance data. This is a necessary step to obtain the original measurement information and provides the basic input for subsequent data processing and attitude calculation.

[0051] Next, the median filtering algorithm is used to filter the first distance data to obtain the filtered second distance data. The median filtering algorithm is a non-linear digital filtering technique that can effectively remove impulse noise while retaining the edge information of the signal, which is crucial for subsequent calculation of the cross-sectional shape and attitude of the copper tube based on the distance data. Through median filtering, the data can be initially smoothed, the influence of random noise can be reduced, and a more stable basis for subsequent outlier detection can be provided.

[0052] Finally, based on the filtered data, further outlier detection and elimination are performed. Specifically, calculate the standard deviation of the filtered second distance data, and set a preset outlier coefficient N, which can be set according to actual application requirements, for example, taking a value of 2 or 3. Then, compare the absolute value of the difference between the original first distance data and the filtered second distance data. If the absolute value of the difference between the first distance data and the second distance data is greater than N times the standard deviation, the corresponding first distance data is determined as an outlier and is eliminated.

[0053] This method combines the characteristics of filtered and smoothed data to judge the outliers in the original data, and can more robustly identify and remove those abnormal measurement values that are significantly inconsistent with the overall data distribution. By eliminating outliers, it is possible to avoid excessive interference of individual incorrect measurement points on the subsequent calculation process, and finally obtain more reliable distance data for subsequent copper tube attitude calculation.

[0054] Furthermore, step S2 includes: S21: Construct a coordinate system for the cross-section of the copper tube, with the plane where the laser displacement sensor is located as the XY plane, the axial direction of the copper tube as the Z axis, and the origin located at the origin of the straightening machine coordinate system; S22: According to the spatial position coordinates, combined with the coordinate transformation matrix, transform the spatial position coordinates of each laser displacement sensor to the coordinate system of the copper tube cross-section to obtain the plane coordinates of each laser displacement sensor in the coordinate system of the copper tube cross-section; S23: According to the distance data and the plane coordinates of each laser displacement sensor, use the least squares method to fit the circle of the copper tube cross-section to obtain the center coordinates and radius of the fitted circle; S24: Take the center coordinates as the center position coordinates of the copper tube cross-section, and calculate the deviation between the distance data and the theoretical distance on the corresponding fitted circle; S25: According to the deviation, use the gradient descent method to iteratively optimize the torsion angle of the copper tube cross-section until the sum of the squares of the deviations is less than the preset threshold, and take the final torsion angle as the cross-sectional torsion angle of the copper tube cross-section.

[0055] Among them, the coordinate transformation matrix refers to a mathematical tool used for point or vector coordinate transformation between different coordinate systems, which can be implemented by a combination of a rotation matrix and a translation vector. The least squares fitting refers to a mathematical optimization technique that finds the best function match for data by minimizing the sum of the squares of errors, which can be implemented by an iterative algorithm or an analytical solution. The gradient descent iterative optimization refers to a commonly used optimization algorithm that gradually adjusts parameters to minimize the function value by moving along the direction of the gradient descent of the objective function, which can be implemented by an iterative process with a fixed step size or an adaptive step size.

[0056] For example, in a specific implementation, assume that the coordinate system of the straightening machine is O-XYZ. Construct the coordinate system O'-X'Y'Z' of the copper tube cross-section, where O' coincides with O, the X'Y' plane is parallel to the plane where the laser displacement sensor is located, and the Z' axis is along the axial direction of the copper tube. Assume that the plane where the sensor is located is parallel to the XY plane of the straightening machine coordinate system, and the axis of the copper tube is parallel to the Z axis of the straightening machine coordinate system, then the coordinate system O'-X'Y'Z' of the copper tube cross-section coincides with the coordinate system O-XYZ of the straightening machine.

[0057] Suppose there are M laser displacement sensors, and their spatial position coordinates in the straightening machine coordinate system are respectively , i = 1,..., M. Since the coordinate system of the copper tube cross-section coincides with the coordinate system of the straightening machine, the spatial position coordinates of the sensor in the coordinate system of the copper tube cross-section are still . Convert the spatial position coordinates to plane coordinates, that is, take the first two components, and obtain the plane coordinates of the sensor in the coordinate system of the copper tube cross-section .

[0058] Real-time collect the distance data from each sensor to the copper tube cross-section .

[0059] Use the least squares method to fit the copper tube cross-section circle. Set the initial center coordinates and the initial radius . The fitting goal is to find the center coordinates (xc, yc) and the radius r such that is minimized. This can be achieved through iterative optimization, such as using the Gauss-Newton method. In each iteration, calculate the theoretical distance from the position of each laser displacement sensor to the currently fitted circle according to the current parameters, and calculate the deviation from the actual distance . Update the center and radius according to the deviation until convergence. Take the finally obtained center coordinates (xc, yc) as the center position coordinates of the copper tube cross-section.

[0060] Calculate the distance data measured by each sensor The theoretical distance on the corresponding fitted circle The deviation between .

[0061] The gradient descent method is used to iteratively optimize the torsion angle θ of the copper tube cross-section. Establish the objective function: , where represents the calculated deviation after considering the torsion angle θ. The initial torsion angle is set to . In each iteration, calculate the gradient of the objective function with respect to the torsion angle: . Update the torsion angle along the opposite direction of the gradient: . Where α is the learning rate. Repeat the iteration until the sum of squared deviations is less than the preset threshold. Take the final torsion angle θ as the cross-section torsion angle of the copper tube cross-section.

[0062] Through the above technical solution, the present application can accurately associate the spatial position of the laser displacement sensor in the straightening machine coordinate system with the measurement points on the copper tube cross-section, and accurately and robustly solve the central position and dynamic torsion angle of the copper tube cross-section from the discrete distance data at the same time, solving the technical problem of real-time sensing of the posture change of the copper tube during high-speed straightening.

[0063] Further, step S22 includes: S221: Construct a coordinate transformation matrix, which includes a rotation matrix and a translation vector; S222: Represent the spatial position coordinates of each laser displacement sensor as homogeneous coordinates, and multiply the coordinate transformation matrix by the homogeneous coordinates to obtain the cross-section homogeneous coordinates of each laser displacement sensor in the copper tube cross-section coordinate system; S223: Extract the first two components in the cross-section homogeneous coordinates as the plane coordinates of each laser displacement sensor in the copper tube cross-section coordinate system.

[0064] Among them, the coordinate transformation matrix refers to the mathematical representation used to describe the transformation relationship between one coordinate system and another coordinate system, and it can be implemented in the matrix form including the rotation matrix and the translation vector.

[0065] The rotation matrix refers to the matrix that describes the rotation relationship between two coordinate systems. The translation vector refers to the vector that describes the translation relationship between the origins of two coordinate systems.

[0066] The homogeneous coordinate refers to an extended coordinate representation method, which can uniformly represent linear transformations (such as rotation, scaling) and translation transformations as matrix multiplications.

[0067] In one embodiment, the construction of the coordinate transformation matrix can be obtained based on a pre - performed system calibration. This matrix can be a 4x4 matrix, where the upper - left corner can be a 3x3 rotation matrix, the first three elements of the right - most column can be a 3x1 translation vector, and the bottom - most row can be [0, 0, 0, 1]. The spatial position coordinates of the laser displacement sensor in the straightening machine coordinate system are represented as a homogeneous coordinate column vector . Multiply the constructed 4x4 coordinate transformation matrix by this 4x1 homogeneous coordinate column vector to obtain a 4x1 cross - section homogeneous coordinate column vector. Extract the first two elements of this cross - section homogeneous coordinate column vector, and the planar coordinates of the sensor in the copper tube cross - section coordinate system can be obtained .

[0068] Further, step S23 includes: S231: Set the initial center coordinates and initial radius of the initial fitting circle, and set the maximum number of iterations; S232: According to the distance data and the planar coordinates of each laser displacement sensor, calculate the initial distance deviation of each laser displacement sensor from the initial fitting circle, and calculate the initial sum of squares of all initial distance deviations; S233: Determine whether the current initial sum of squares is less than the initial sum of squares of the previous iteration. If so, accept the current adjustment result, update the number of iterations, and return to S232 to continue the next iteration; otherwise, reduce the step size of the gradient descent method, readjust the initial center coordinates and initial radius. If the calculated initial sum of squares after adjustment is still not less than the initial sum of squares of the previous iteration and the step size is less than the preset threshold, stop the iteration and output the center coordinates and the radius of the fitting circle corresponding to the minimum initial sum of squares during the iteration process; otherwise, execute S234; S234: Determine whether the current number of iterations has reached the maximum number of iterations. If so, output the center coordinates and radius of the current fitting circle after iteration; otherwise, return to S232.

[0069] This solution elaborates in detail the process of using iterative optimization to implement the least - squares fitting of the copper tube cross - section circle. First, set an initial fitting circle and the maximum number of iterations in the iterative process to provide a starting point and a termination condition for subsequent calculations.

[0070] Next, according to the real - time distance data and the sensor planar coordinates, calculate the initial distance deviation between the initial fitting circle and the actual measurement points, and calculate the sum of squares of these initial distance deviations. This sum of squares is used as an objective function to measure the quality of the fitting.

[0071] During the iteration process, it is determined whether the initially calculated sum of squares is less than the sum of squares in the previous iteration to evaluate the effect of the current parameter adjustment. If the sum of squares decreases, it indicates that the parameter adjustment direction is correct. Then, the gradient descent method is used to adjust the center coordinates and radius along the direction in which the sum of squares decreases, and the iteration count is recorded. If the sum of squares does not decrease, it means that the current adjustment amplitude (step size) may be inappropriate, and the step size needs to be reduced, and then the parameter adjustment is retried. When the step size is reduced to less than the preset threshold, it is considered that the iteration process is close to convergence or cannot be further optimized. At this time, the iteration is terminated, and the initial center coordinates and initial radius corresponding to the minimum result of the sum of squares in the entire iteration process are selected as the optimal solution.

[0072] In addition, to ensure real-time performance, a maximum iteration count is also set as a forced termination condition. Even if the preset threshold of the step size is not reached, the calculation will be terminated when the iteration count reaches the upper limit.

[0073] Finally, the center coordinates and radius obtained through iterative optimization are output as the fitting result of the circular cross-section of the copper tube. Through this iterative optimization and combined with the dynamic step size adjustment strategy, this solution can overcome problems such as poor convergence and insufficient stability that may be encountered in the practical application of the standard least squares method, and improve the accuracy of the fitting result. This accurate and real-time fitting result of the circular cross-section provides reliable basic data for subsequent calculation of the center position and torsion angle of the copper tube cross-section, thereby improving the accuracy and robustness of the entire dynamic compensation method for copper tube straightening.

[0074] For example: in step S231, the initial center coordinates of the initial fitting circle can be set as the origin (0, 0) of the copper tube cross-section coordinate system, the initial radius can be set as half of the standard outer diameter of the copper tube to be straightened, and the maximum iteration count can be set to, for example, 200 times.

[0075] In step S232, for each laser displacement sensor i, its planar coordinates in the copper tube cross-section coordinate system are , and the distance data collected in real time is . The center coordinates of the current fitting circle are (xc, yc), and the radius is R. Calculate the distance from sensor i to the center of the current fitting circle as . The distance deviation is calculated as . The sum of the squares of the distance deviations of all sensors is calculated as .

[0076] In step S233, compare the initially calculated sum of squares in the current iteration with the sum of squares in the previous iteration. If the current sum of squares is smaller, update the center coordinates and radius according to the gradient descent method. For example, , , , where is the current step size; , is the partial derivative of the initial sum of squares of the circular coordinates, is the partial derivative of the initial sum of squares of the radius. At the same time, the iteration count is incremented by one. If the current initial sum of squares does not decrease, the current step size is multiplied by a decay factor, such as 0.5, and then the adjustment amount of the parameters is recalculated using the new step size, and the parameters are adjusted again. Determine whether the new step size is less than a preset threshold. If it is less than, stop the iteration and output the center coordinates and radius of the fitted circle corresponding to the minimum value of the initial sum of squares during the iteration. If the step size is greater than or equal to the preset threshold, proceed to S234.

[0077] In step S234, determine whether the current iteration count has reached 200 times. If it has reached, output the current center coordinates (xc, yc) and radius R. If it has not reached, return to step S232 and perform the next round of calculation using the new center coordinates and radius.

[0078] Furthermore, step S3 includes: S31: Taking the center position coordinates of the copper tube cross-section and the cross-section torsion angle as inputs, and the bending moment and torque applied by the straightening rolls to the copper tube as outputs, establish the functional relationship between the center position coordinates, cross-section torsion angle and bending moment, torque, and use this functional relationship as the attitude-mechanical action correlation model; S32: Set the target attitude of the copper tube as the ideal center position coordinates and zero torsion angle. According to the target attitude, combined with the attitude-mechanical action correlation model, calculate the target straightening mechanical action; S33: According to the center position coordinates and cross-section torsion angle of the current copper tube cross-section, combined with the attitude-mechanical action correlation model, calculate the actual straightening mechanical action in the current attitude, and calculate the mechanical deviation between the target straightening mechanical action and the actual straightening mechanical action; S34: Calculate the compensation adjustment amount of each straightening roll according to the mechanical deviation.

[0079] Among them, the attitude-mechanical action correlation model refers to the functional relationship between the center position coordinates of the copper tube cross-section, the cross-section torsion angle and the bending moment, torque applied by the straightening rolls to the copper tube. Specifically, methods such as finite element analysis, experimental data fitting or analytical mechanical models can be used to establish this model. This model takes the attitude of the copper tube as the input and outputs the mechanical actions (bending moment and torque) applied by the straightening rolls to the copper tube in this attitude. Specifically: Assume that the attitude-mechanical action correlation model is established through finite element simulation and simplified to a polynomial function. The input is the center position coordinates (x, y) of the copper tube cross-section and the cross-section torsion angle θ, and the output is the bending moment and torque The attitude-mechanical action correlation model can be expressed as: ; ; ; where, 、 、 、 、 、 、 、 、 、 、 、 are coefficients determined by simulation or experiment. Since within the small offset and small angle range, the geometric and mechanical responses exhibit linear characteristics, the attitude-mechanical action correlation model can be represented by a linear equation.

[0080] Set the target attitude of the copper tube as the ideal center position coordinates and zero torsion angle. Therefore, the target attitude of the copper tube is (x = 0, y = 0, θ = 0); the target straightening mechanical action applied is . These target mechanical actions can be determined by inputting the target attitude into the attitude-mechanical action correlation model.

[0081] Obtain the center position coordinates (xc, yc) and cross-section torsion angle θc of the current copper tube cross-section in real time. Using (xc, yc, θc) as the input, calculate the target straightening mechanical action at the current attitude by using the attitude-mechanical action correlation model.

[0082] Calculate the mechanical deviation: , , .

[0083] According to the mechanical deviation , calculate the compensation adjustment amount of each straightening roll. Assume there is a mapping relationship, such as another linear model or look-up table, that maps the mechanical deviation to the radial adjustment amount ΔR and tilt angle adjustment amount of the straightening roll: ;

[0084] According to the calculated ΔR and , determine the specific compensation adjustment amount of each straightening roll.

[0085] Furthermore, step S34 includes: S341: Establish a mapping relationship between the straightening roll adjustment amount and the mechanical deviation. This mapping relationship is obtained through experiments or simulations and characterizes the relationship between the bending moment and torque applied by the straightening rolls to the copper tube and the target mechanical action at different straightening roll positions; S342: Calculate the compensation adjustment amount for each straightening roll based on the mechanical deviation and in combination with the mapping relationship.

[0086] This solution provides a specific method for converting the calculated mechanical deviation into the compensation adjustment amount of the straightening rolls. By establishing a mapping relationship between the straightening roll adjustment amount and the mechanical deviation, it provides a basis for the conversion from mechanical deviation to mechanical adjustment amount. This mapping relationship is obtained through experiments or simulations, ensuring its reliability based on the actual physical process or its simulation, and can accurately reflect the impact of the straightening roll position change on the applied mechanical action and the difference from the target mechanical action.

[0087] On this basis, according to the calculated mechanical deviation and in combination with this mapping relationship, the compensation adjustment amount for each straightening roll can be calculated. This process utilizes the pre-established corresponding relationship, making the conversion from the abstract mechanical deviation to the specific mechanical adjustment amount feasible and efficient.

[0088] This conversion mechanism enables the entire dynamic compensation system to calculate the mechanical action deviation based on the real-time posture change of the copper tube and accurately determine how to adjust the straightening rolls, so as to offset the mechanical action deviation caused by the posture change and achieve precise straightening of the copper tube. Combined with the solution for calculating the mechanical action deviation based on the copper tube posture, it forms a complete closed-loop of dynamic mechanical action compensation based on real-time posture perception, provides the key link for converting the mechanical action deviation into the mechanical adjustment amount, enables the realization of the entire compensation process, and solves the straightening accuracy problem caused by the failure to effectively handle dynamic torsion in the prior art.

[0089] Further, step S4 includes: S41: Obtain the actual position parameters of the straightening roll actuator in real time; S42: Compare the compensation adjustment amount with the actual position parameters to obtain a position deviation, and determine whether the position deviation exceeds a preset deviation threshold; S43: If the position deviation exceeds the preset deviation threshold, drive the straightening roll actuator to adjust the position of the straightening roll until the position deviation is less than or equal to the preset deviation threshold to compensate for the straightening mechanical action deviation caused by the copper tube posture change.

[0090] Among them, the actual position parameters include the current actual radial position and the actual tilt angle of the straightening roller. The actual radial position refers to the real-time vertical distance between the center line of the straightening roller and the ideal central axis of the copper tube, and the radial direction refers to the direction perpendicular to the axial direction of the copper tube movement. The actual tilt angle is the real-time angle formed by the rotation axis of the straightening roller itself relative to the reference axis of the straightening machine. In a multi-roller straightening machine, in order to better apply a straightening force to the copper tube, the straightening roller itself is arranged at a certain angle, and this angle can be adjusted.

[0091] The position deviation actually makes two independent comparisons, namely the radial position deviation and the tilt angle deviation. Correspondingly, the preset deviation threshold also includes two corresponding thresholds, namely a threshold for the radial position deviation and a threshold for the tilt angle deviation.

[0092] Among them, if the radial position deviation exceeds the radial position deviation threshold, or the tilt angle deviation exceeds the tilt angle deviation threshold, the driving straightening roller actuator adjusts the position of the straightening roller until both the radial position deviation and the tilt angle deviation are less than or equal to their respective preset deviation thresholds.

[0093] This solution constructs a more precise straightening roller position control link by introducing real-time feedback on the actual position of the straightening roller actuator and a closed-loop adjustment mechanism based on deviation.

[0094] Specifically, after calculating the compensation adjustment amount of the straightening roller according to the change in the copper tube attitude, the system does not simply send a one-time adjustment instruction, but first obtains the current actual position of the actuator in real time. Subsequently, the calculated compensation adjustment amount (representing the target position) is compared with the real-time obtained actual position, and the position deviation between the two is calculated. This deviation quantifies the gap between the current position of the actuator and the desired compensation position.

[0095] The system determines whether this position deviation exceeds the preset allowable range, that is, the preset deviation threshold. If the deviation is too large, it indicates that the actuator has not adjusted the straightening roller to a position that meets the accuracy requirements, and the system will continuously drive the actuator to make adjustments. This adjustment process is iterative or continuous, and the key is that it will continue, while continuously obtaining new actual position parameters in real time and recalculating the position deviation until the detected position deviation is reduced within the preset deviation threshold.

[0096] This control method based on real-time feedback and deviation convergence can effectively overcome various uncertain factors that may be encountered during the movement of the actuator, such as mechanical clearance, friction change, load fluctuation, or the nonlinearity of the control system, etc., ensuring that the actual position of the straightening roller can accurately approach the target compensation position calculated in real time according to the copper tube attitude.

[0097] Please refer toFigure 2 , Figure 3 , a dynamic compensation system for copper tube straightening, characterized in that it is used to implement any of the above methods, and the system includes: Acquisition module 201: Acquire the spatial position coordinates of each laser displacement sensor inside the straightening machine, and the distance data of each point on the cross-section of the copper tube collected by the laser displacement sensor in real time; Calculation module 202: According to the distance data and the spatial position coordinates of each laser displacement sensor, calculate the central position coordinates and cross-section torsion angle of the copper tube cross-section in real time; Calculation module 203: According to the central position coordinates and cross-section torsion angle, combined with the preset attitude-mechanical action correlation model, calculate the compensation adjustment amount of the straightening roll; Compensation module 204: According to the compensation adjustment amount, drive the straightening roll actuator to adjust the position of the straightening roll to compensate for the deviation of the straightening mechanical action caused by the change of the copper tube attitude.

[0098] Among them, the acquisition module 201 refers to the functional unit for collecting original measurement data, which can be connected to the laser displacement sensor through hardware interfaces such as data acquisition cards, industrial camera interfaces or sensor bus interfaces, and is realized in cooperation with corresponding driver programs and data acquisition software.

[0099] The calculation module 202 refers to the functional unit for processing the original measurement data and extracting the copper tube attitude information, which can use hardware carriers such as high-performance processors, digital signal processors or embedded computing platforms, and is realized by running attitude calculation algorithm software.

[0100] The calculation module 203 refers to the functional unit for calculating the straightening roll adjustment amount according to the copper tube attitude information, which can use hardware platforms such as industrial control computers, programmable logic controllers or special motion controllers, and is realized by running compensation calculation algorithm software.

[0101] The compensation module 204 refers to the functional unit for converting the calculated adjustment amount into a control signal for the straightening roll actuator, which can use hardware devices such as servo drivers, stepper motor controllers or hydraulic proportional valve controllers, and is realized in cooperation with corresponding control software.

[0102] The dynamic compensation system for copper tube straightening provided by this application decomposes the functions of the dynamic compensation method for copper tube straightening into four modules: acquisition, calculation, calculation and compensation, and clarifies the functional responsibilities and data flow of each module, forming a complete control loop.

[0103] The acquisition module 201, as the perception layer of the system, is responsible for collecting the first distance data of the copper tube cross-section and the sensor position information in real time and accurately, providing a basis for subsequent processing. The solution module 202 receives the original data and, based on the sensor position information, converts the distance data into the central position and torsion angle of the copper tube cross-section with physical significance through geometric calculations and optimization algorithms, which is the key to converting the sensor signal into the copper tube attitude information. The calculation module 203 then uses the attitude information output by the solution module, combines it with the preset attitude-mechanical action correlation model, predicts the straightening mechanical action required under the current copper tube attitude, and compares it with the desired mechanical action to calculate the compensation adjustment amount that the straightening rollers need to make. The compensation module 204, as the execution layer of the system, receives the adjustment amount output by the calculation module and drives the actuator of the straightening rollers (such as a servo motor or a hydraulic cylinder) to accurately adjust the position of the straightening rollers, thereby changing the mechanical action exerted by the straightening rollers on the copper tube and realizing the real-time compensation for the mechanical action deviation caused by the copper tube attitude change.

[0104] It is precisely due to this modular system architecture design that the above method can be executed efficiently and in real time. The data interaction and processing speed between modules are guaranteed, so that it can quickly respond to the dynamic attitude changes of the copper tube and achieve precise dynamic compensation control. The combination of this system structure and method effectively solves the dynamic torsion problem during the copper tube straightening process, improving the straightening accuracy and stability.

[0105] In this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0106] The above description is only for the embodiments of the present application and does not limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A dynamic compensation method for straightening copper pipe, which is used for a straightening machine to straighten copper pipes, is characterized in that, The method includes the steps of: S1: Obtain the spatial position coordinates of each laser displacement sensor inside the straightening machine, and the distance data of each point on the cross-section of the copper tube collected by the laser displacement sensor in real time; S2: According to the distance data and the spatial position coordinates of each laser displacement sensor, calculate the central position coordinates and the cross-section torsion angle of the copper tube cross-section in real time; S3: According to the central position coordinates and the cross-section torsion angle, and in combination with a preset attitude-mechanical action correlation model, calculate the compensation adjustment amount of the straightening rolls; S4: According to the compensation adjustment amount, drive the straightening roll actuator to adjust the position of the straightening rolls to compensate for the deviation of the straightening mechanical action caused by the change in the attitude of the copper tube.

2. A dynamic compensation method for straightening copper pipe materials according to claim 1, characterized in that Step S1 includes: S11: Calibrate each laser displacement sensor to obtain the spatial position coordinates of each laser displacement sensor in the straightening machine coordinate system; S12: Set the data acquisition frequency of the laser displacement sensor, and dynamically adjust the data acquisition frequency according to the movement speed of the copper tube to ensure that the distance between adjacent two data acquisition points is less than a preset threshold in the movement direction of the copper tube; S13: Start the laser displacement sensor and collect the distance data of each point on the cross-section of the copper tube in real time according to the data acquisition frequency.

3. A dynamic compensation method for straightening copper pipe materials according to claim 2, characterized in that, Step S13 includes: S131: Collect the first distance data of each point on the cross-section of the copper tube in real time; S132: Use the median filtering algorithm to filter the first distance data to obtain the filtered second distance data; S133: Calculate the standard deviation of the second distance data. If the absolute value of the difference between the first distance data and the second distance data is greater than N times the standard deviation, it is determined as an outlier and eliminated to obtain the distance data; where N is a preset outlier coefficient.

4. A dynamic compensation method for straightening copper pipes according to claim 2, characterized in that Step S2 includes: S21: Construct a copper tube cross-section coordinate system, with the plane where the laser displacement sensor is located as the XY plane, the axial direction of the copper tube as the Z axis, and the origin located at the origin of the straightening machine coordinate system; S22: According to the spatial position coordinates, and in combination with the coordinate transformation matrix, transform the spatial position coordinates of each laser displacement sensor to the copper tube cross-section coordinate system to obtain the plane coordinates of each laser displacement sensor in the copper tube cross-section coordinate system; S23: According to the distance data and the plane coordinates of each laser displacement sensor, use the least squares method to fit the copper tube cross-section circle to obtain the center coordinates and radius of the fitted circle; S24: Use the center coordinates as the central position coordinates of the copper tube cross-section, and calculate the deviation between the distance data and the theoretical distance on the corresponding fitted circle; S25: According to the deviation, use the gradient descent method to iteratively optimize the torsion angle of the copper tube cross-section until the sum of the squares of the deviations is less than a preset threshold, and use the final torsion angle as the cross-section torsion angle of the copper tube cross-section.

5. A dynamic compensation method for straightening copper pipe materials according to claim 4, characterized in that, Step S22 includes: S221: Construct a coordinate transformation matrix, and the coordinate transformation matrix includes a rotation matrix and a translation vector; S222: Represent the spatial position coordinates of each laser displacement sensor as homogeneous coordinates, and multiply the coordinate transformation matrix by the homogeneous coordinates to obtain the cross-section homogeneous coordinates of each laser displacement sensor in the copper tube cross-section coordinate system; S223: Extract the first two components of the homogeneous coordinates of the cross-section as the plane coordinates of each laser displacement sensor in the copper tube cross-section coordinate system.

6. A dynamic compensation method for straightening copper pipe materials according to claim 4, characterized in that, Step S23 includes: S231: Set the initial center coordinates and initial radius of the initial fitting circle, and set the maximum number of iterations. S232: According to the distance data and the plane coordinates of each laser displacement sensor, calculate the initial distance deviation of each laser displacement sensor from the initial fitting circle, and calculate the initial sum of squares of all the initial distance deviations. S233: Determine whether the current initial sum of squares is less than the initial sum of squares of the previous iteration. If so, accept the current adjustment result, update the number of iterations, and return to S232 for the next iteration; otherwise, reduce the step size of the gradient descent method, readjust the initial center coordinates and initial radius. If the calculated initial sum of squares after adjustment is still not less than the initial sum of squares of the previous iteration and the step size is less than the preset threshold, stop the iteration and output the center coordinates and radius of the fitting circle corresponding to the minimum initial sum of squares during the iteration; otherwise, execute S234. S234: Determine whether the current number of iterations has reached the maximum number of iterations. If so, output the center coordinates and radius of the current fitting circle after iteration; otherwise, return to S232.

7. A dynamic compensation method for straightening copper tubes according to claim 1, characterized in that Step S3 includes: S31: Take the center position coordinates and cross-section torsion angle of the copper tube cross-section as inputs, and take the bending moment and torque applied by the straightening rolls to the copper tube as outputs, establish the functional relationship between the center position coordinates, cross-section torsion angle and bending moment, torque, and use this functional relationship as the attitude-mechanical action correlation model. S32: Set the target attitude of the copper tube as the ideal center position coordinates and zero torsion angle. According to the target attitude, combine with the attitude-mechanical action correlation model, and calculate the target straightening mechanical action. S33: According to the center position coordinates and cross-section torsion angle of the current copper tube cross-section, combine with the attitude-mechanical action correlation model, calculate the actual straightening mechanical action in the current attitude, and calculate the mechanical deviation between the target straightening mechanical action and the actual straightening mechanical action. S34: Calculate the compensation adjustment amount of each straightening roll according to the mechanical deviation.

8. A dynamic compensation method for straightening copper pipe materials according to claim 7, characterized in that Step S34 includes: S341: Establish the mapping relationship between the straightening roll adjustment amount and the mechanical deviation. This mapping relationship is obtained through experiments or simulations, and characterizes the relationship between the bending moment and torque applied by the straightening rolls to the copper tube and the target mechanical action at different straightening roll positions. S342: Calculate the compensation adjustment amount of each straightening roll according to the mechanical deviation and in combination with the mapping relationship.

9. A dynamic compensation method for straightening copper pipe materials according to claim 1, characterized in that Step S4 includes: S41: Real-time obtain the actual position parameters of the straightening roll actuator. S42: Compare the compensation adjustment amount with the actual position parameters to obtain the position deviation, and determine whether the position deviation exceeds the preset deviation threshold. S43: If the position deviation exceeds a preset deviation threshold, drive the straightening roll actuator to adjust the position of the straightening roll until the position deviation is less than or equal to the preset deviation threshold, so as to compensate for the deviation of the straightening mechanical action caused by the change of the copper tube posture.

10. A dynamic compensation system for copper pipe straightening, characterized in that, For implementing the method described in any one of claims 1-9 above, the system includes: An acquisition module: acquire the spatial position coordinates of each laser displacement sensor inside the straightening machine, and the distance data of each point on the cross-section of the copper tube collected by the laser displacement sensor in real time; A calculation module: calculate the central position coordinates and the cross-section torsion angle of the copper tube cross-section in real time according to the distance data and the spatial position coordinates of each laser displacement sensor; A computing module: calculate the compensation adjustment amount of the straightening roll according to the central position coordinates and the cross-section torsion angle, in combination with a preset attitude-mechanical action correlation model; A compensation module: drive the straightening roll actuator to adjust the position of the straightening roll according to the compensation adjustment amount, so as to compensate for the deviation of the straightening mechanical action caused by the change of the copper tube posture.

Images