Edge auxiliary traction system and method for longitudinal large-curvature forming of roller-coated hyperbolic aluminum plate

Abstract

The invention relates to the technical field of roller coating hyperbolic aluminum plate machining control, in particular to an edge auxiliary traction system and method for longitudinal large-curvature forming of a roller coating hyperbolic aluminum plate. The edge auxiliary traction system comprises a clamping pre-deformation unit, when a main stretcher is started, a traction clamping jaw pulls down at a basic speed, and a dynamic proportional relation between the edge stretching speed and the central stretching speed is established; during stretching, when the displacement increment reaches a threshold value, the traction force is proportionally distributed according to the distance from the center line, the pull-down force is updated in real time, when the strain deviation exceeds the limit, a deviation area is positioned through a multi-modal array, the traction speed and the pull-down force of the area are increased, and the local curvature radius reaches a critical range, a reinforced traction mode is started; speed and plastic flow phase locking and grain orientation regulation and control are achieved, traction force is maintained till stress is released in the pressure maintaining stage, the longitudinal large-curvature forming precision of the roller-coated hyperbolic aluminum plate is improved, wrinkles and cracks are reduced, and the method is suitable for machining of the high-precision hyperbolic aluminum plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of roll-coated double-curved aluminum plate processing control, in particular to an edge auxiliary traction system and method for roll-coated double-curved aluminum plate longitudinal large-curvature forming. BACKGROUND

[0002] Roll-coated double-curved aluminum plate processing control is an important technology. In the fields of building curtain walls and rail transit, roll-coated double-curved aluminum plates are widely used due to their aesthetic appearance and mechanical properties. The longitudinal large-curvature forming of the plates needs to be cooperatively pulled by a stretching machine on the edge and central area of the plate to avoid defects such as wrinkles and cracks. In the prior art, the edge traction in the aluminum plate stretching process is controlled by a fixed proportional speed and a uniform traction force distribution mode. The edge traction speed is set as a fixed multiple of the central stretching speed, and the pulling force of each jaw is distributed in equal proportion to achieve basic forming control. This method relies on a mechanical synchronization mechanism to ensure the cooperation of speed and force. In the small-curvature forming scenario, the basic requirements can be met. However, in the longitudinal large-curvature forming, the prior art has significant limitations. First, the speed and traction force control adaptability is insufficient. The fixed proportional speed cannot compensate for the material flow lag effect, especially when the stretching rate suddenly changes. The edge is prone to wrinkles due to speed lag. The uniform traction force distribution does not consider the stress gradient demand in the width direction of the plate. The edge area cannot be fully curved due to insufficient stress. Second, there is a lack of deviation correction mechanism. When the local strain deviation exceeds the limit, the prior art lacks a multi-modal monitoring means to locate the deviation area and cannot correct the deformation through micro-control, which easily causes local cracking. Third, the control of the critical deformation zone is weak. In the critical stage of rapid reduction of the curvature radius, there is no dynamic coupling mechanism between speed and plastic flow, which leads to stress concentration and reduction of forming accuracy. These defects make it difficult for the prior art to meet the high-quality requirements of roll-coated double-curved aluminum plate longitudinal large-curvature forming. To solve this problem, we provide an edge auxiliary traction system and method for roll-coated double-curved aluminum plate longitudinal large-curvature forming. SUMMARY

[0003] The purpose of the present application is to provide an edge auxiliary traction system and method for roll-coated double-curved aluminum plate longitudinal large-curvature forming to solve the problems raised in the background art.

[0004] 1. Since the fixed proportional speed of the prior art cannot compensate for the material flow lag, and the uniform traction force is not suitable for the stress gradient demand, the present case sets the edge and central speed by dynamic proportioning and distributes the traction force according to the distance from the center line, which can reduce edge wrinkles and ensure full curvature forming.

[0005] 2. Due to the lack of deviation positioning and micro-control in existing technologies, the coupling between velocity and plastic flow in the critical region is insufficient. Therefore, this case uses multi-modal positioning of the deviation area to activate the strengthening mode to achieve phase locking between velocity and plastic flow, which can correct local deformation and improve molding accuracy.

[0006] To achieve the above objectives, an edge-assisted traction system for longitudinal large curvature forming of roll-coated hyperbolic aluminum sheets is provided, including a clamping pre-deformation unit. When the main stretching machine start signal is triggered, all traction grippers initiate a downward pulling action at a preset base speed. Simultaneously, a mathematical relationship is set between the edge traction speed and the central stretching speed. The system is characterized by further comprising: During the main stretching process, when the displacement increment of the longitudinal stretching machine reaches the preset displacement threshold, the pulling force of each traction jaw is automatically updated according to the strain increment of the roll-coated hyperbolic aluminum plate, and the traction force is distributed according to the distance of each traction jaw from the center line of the roll-coated hyperbolic aluminum plate. When the deviation between the actual strain increment of the edge of the roll-coated hyperbolic aluminum plate monitored in real time and the target value exceeds the preset deviation threshold, the deviation area is located and the edge traction speed and pulling force of the traction jaw in the deviation area are increased. When the local curvature radius of the deviation area drops to the preset curvature radius range, the local area enhanced traction mode is activated, that is, the edge traction speed of the traction jaw in the deviation area is set according to the central stretching speed at this time. After the main stretching machine enters the pressure holding stage, the pulling force of all traction jaws is maintained until the forming stress is released, and the edge auxiliary traction is completed.

[0007] The second objective of this invention is to provide a method for implementing an edge-assisted traction system for longitudinal large curvature forming of roll-coated hyperbolic aluminum sheets, comprising the following steps: S1. When the main stretching machine start signal is triggered, the pull-down action of all traction grippers is activated synchronously. The dynamic proportional relationship between the edge traction speed and the central stretching speed is established through the speed command generator. At the same time, the initial position of the traction grippers is lower than the mold plane to form a pre-deformation zone. S2. When the displacement increment of the longitudinal tensioning machine reaches the threshold, the material deformation analysis module is called to convert the displacement into strain increment and generate a gradient traction force distribution map based on the spatial location data. S3. When the strain deviation exceeds the threshold, multi-modal positioning is initiated, triggering the velocity phase-locked loop and grain orientation modulator to achieve microscopic collaborative control. S4. During the pressure holding stage, maintain the gradient traction force and initiate the graded unloading procedure by monitoring the grain boundary recombination signal.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The dynamic proportional relationship between the edge traction speed and the central stretching speed is established by the speed command generator, combined with the material flow compensation algorithm, the proportional coefficient is dynamically adjusted according to the stretching rate change, the material flow hysteresis effect is accurately compensated, the edge wrinkles caused by speed hysteresis are avoided, at the same time, the traction force is distributed in proportion to the distance from the center line of the traction clamping jaw, forming a gradient stress field increasing from the center to the edge, matching the edge strain demand required by large curvature forming, solving the problem of insufficient edge forming caused by traditional uniform traction force, ensuring that the stress distribution in the width direction of the plate matches the curvature change.

[0009] 2. A multi-modal fusion detection array is used to locate the deviation area through the spatial superposition of temperature anomalies and curvature mutations, realize the three-dimensional accurate positioning of the abnormal area, and realize the stepless speed regulation of the edge traction speed through the speed compensation controller for the deviation area, combined with the dynamic enhancement of the stepped force pulse to improve the downward force, so that the speed and the pulling force are accurately adjusted to the abnormal area, quickly correct the local strain deviation, avoid the secondary stress concentration caused by single parameter adjustment, and effectively reduce the cracking risk.

[0010] 3. When the local curvature radius decreases to the critical range, the dynamic curvature coupling control is started, the edge speed and the central speed are electromagnetically synchronized through the speed phase-locked loop, the stretching rhythm is highly coordinated, the adaptive waveform tension is generated by activating the bionic hydraulic tendon group, the influence of material stress relaxation is offset, the crystal orientation modulator is started to guide the grain to preferentially arrange along the curvature normal, the material plastic deformation ability is improved, at the same time, the edge traction speed and the internal plastic flow rate form a phase-locked loop control through the eddy current field synchronous technology, avoiding stress concentration in the critical stage, and ensuring the large curvature forming precision. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 The overall block diagram of the present application is shown in the figure; Figure 2 The overall flowchart of the present application is shown in the figure.

[0012] The meanings of various labels in the figure are as follows: 1. Clamping pre-deformation unit. DETAILED DESCRIPTION

[0013] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0014] The present application provides an edge auxiliary traction system for longitudinal large-curvature forming of roll-coated double-curved aluminum plate, please refer to Figure 1As shown, the pre-gripping unit 1 includes a pre-gripping unit 1, when the main stretching machine starts the signal trigger, all the traction clamps start the downward action at a preset basic speed, and the mathematical relationship between the edge traction speed and the central stretching speed is set; The pre-gripping unit 1 includes a speed relationship setting module for setting the mathematical relationship between the edge traction speed and the central stretching speed, which includes: In the process of roll-coating double-curved aluminum plate longitudinal large-curvature forming, the speed relationship setting module of the pre-gripping unit is the core to ensure the synchronous stretching of the edge and the central area. It lays the foundation for the uniform stress distribution in the subsequent forming process by accurately setting the mathematical relationship between the edge traction speed and the central stretching speed. This link not only connects the trigger logic of the main stretching machine start signal, but also responds to the challenges brought by material flow characteristics through dynamic compensation mechanism. The specific implementation is as follows: A traction clamp speed command generator is established, which forms a real-time communication link with the rotation speed sensor of the main stretching machine transmission shaft, continuously receives the transmission shaft rotation speed pulse signal, and converts the transmission shaft rotation speed signal into central stretching speed data through a signal converter. The process is divided into three steps: Pulse counting and frequency conversion, the signal converter counts the pulse signal in 10ms period, converts the pulse frequency (Hz) into the transmission shaft speed (r / min), the formula is: speed=(pulse frequency x 60) / 1024, transmission ratio conversion, according to the gear transmission ratio of the main stretching machine, the transmission shaft speed is converted into the linear speed base of the stretching roller, that is, the stretching roller speed=transmission shaft speed / transmission ratio, linear speed calculation, combined with the diameter of the stretching roller, the final linear speed (unit m / s) is obtained through the formula central stretching speed=stretching roller speed x π x diameter / 60, for example, when the transmission shaft speed is 1000r / min, the central stretching speed is 2.618m / s after conversion, when the proportional operator generates the edge traction speed reference value, the proportional coefficient is set based on the central stretching speed, that is, the edge traction speed reference value=central stretching speed x proportional coefficient. The logic of this initial setting is: The edge of the aluminum plate needs to bear a larger deformation during stretching. Appropriately increasing the edge speed can avoid wrinkles caused by edge lag. For example, when the central stretching speed is 2.618 m / s, the initial edge traction speed reference value is set to 2.88 m / s. The material flow compensation algorithm built in the proportional operator is the key to dynamic adjustment. The core lies in adjusting the proportional coefficient according to the extension characteristics of the transmission shaft speed signal, which refers to the rate of speed change and acceleration characteristics. For example, during the process of increasing the speed from 1000 r / min to 1500 r / min, if it is completed within 0.5 s, it belongs to fast extension, and if it is completed within 2 s, it belongs to slow extension. This characteristic directly reflects the degree of change in the stretching rate of the aluminum plate. When the speed changes rapidly, the internal flow lag effect of the material is more significant, and the speed difference between the edge and the center needs to be further amplified. The compensation algorithm establishes a dynamic mapping model of extension characteristics-proportional coefficient: The first derivative (rate of change of speed) and the second derivative (speed acceleration) of the transmission shaft speed signal are extracted in real time to quantify the extension characteristics. When the rate of change of speed is less than 500 and the acceleration is less than 200 (slow extension), the proportional coefficient is maintained at 1.1-1.2, only compensating for slight lag. When the rate of change of speed is greater than or equal to 500 or the acceleration is greater than or equal to 200 (fast extension), the algorithm triggers nonlinear compensation, and the proportional coefficient is dynamically increased according to the exponential function (coefficient = 1.1 + 0.1 x e^(0.002 x acceleration)). The highest value can reach 1.5. At this time, the edge traction speed is amplified with the rapid increase of the central speed, and a material thickness correction factor is introduced. For every 0.5 mm increase in the thickness of the aluminum plate, the proportional coefficient is increased by 0.05 based on the basic value, to cope with the characteristics of thicker plates with poorer flowability. Through this mechanism, the edge traction speed can accurately compensate for the material flow lag effect: When the central stretching speed increases rapidly due to the increase of the transmission shaft speed, the edge speed is always ahead of the theoretical lag value of the central speed through the dynamic amplification of the proportional coefficient (for example, during the fast extension process of increasing the central speed from 2.618 m / s to 3.927 m / s, the edge speed increases from 2.88 m / s to 5.89 m / s, and the difference increases from 0.262 m / s to 1.963 m / s), ensuring that the stretching amount of the edge of the aluminum plate matches the central area, avoiding edge wrinkles or cracks caused by flow lag, and providing a stable speed reference for subsequent proportional distribution of traction force according to distance.

[0015] characterized in that it further comprises: The clamping pre-deformation unit 1 comprises a material deformation analysis module. In the main stretching process, when the displacement increment of the longitudinal stretching machine reaches the preset displacement threshold, the material deformation analysis module automatically updates the downward force of each traction jaw according to the strain increment of the roll-coated hyperbolic aluminum plate. When the dynamic proportional setting of the edge traction speed and the central stretching speed is completed, the material deformation analysis module needs to update the pull-down force of each traction clamp in real time according to the strain increment of the roll-coated double-curved aluminum plate. This process is the key to realizing the uniform deformation of the aluminum plate, which not only connects the setting logic of the speed reference, but also accurately captures the actual stress state of the material through multi-physical field coupling calculation, providing a scientific basis for the subsequent gradient distribution of the traction force. The material stress-strain conversion model is a dynamic calculation model integrating multiple parameters. Its core function is to convert the mechanical displacement signal of the longitudinal stretching machine into the actual strain state of the aluminum plate. The model has three built-in basic databases and algorithm modules: The roll-coated double-curved aluminum plate elastic modulus database stores the elastic modulus reference values of aluminum plates with different thicknesses and different alloy compositions. The coating adhesion feature library contains the interfacial bonding strength data of the roll-coated coating and the aluminum plate substrate. The real-time temperature compensation algorithm is used to correct the influence of temperature changes on the mechanical properties of the material. The three work together to make the model adapt to strain calculation under different material properties and environmental conditions. The specific process of converting the displacement increment of the longitudinal stretching machine into the actual strain increment of the aluminum plate through multi-physical field coupling calculation is as follows: The displacement sensor of the longitudinal stretching machine collects the cumulative displacement change during the stretching process in real time. After filtering, the signal is input into the conversion model as the initial excitation parameter. The model first calculates the theoretical stress value (σ) according to the displacement increment. where E is the elastic modulus, and the theoretical strain (ε) at the same time. The real-time temperature distribution of the aluminum plate surface is obtained through the infrared temperature measuring instrument, and the real-time temperature compensation algorithm is called to correct the elastic modulus, obtaining the stress value after temperature correction. The role of this "temperature compensation algorithm" is to correct the influence of temperature changes on the elastic modulus of the aluminum plate during the stretching process, ensuring the accuracy of subsequent stress calculation and avoiding the influence of mechanical property parameter deviation caused by temperature fluctuations on the forming precision. The specific correction method is as follows: after obtaining the real-time temperature distribution of the roll-coated double-curved aluminum plate surface through the infrared temperature measuring instrument, the algorithm calls the built-in roll-coated double-curved aluminum plate elastic modulus database. This database stores the elastic modulus reference values of aluminum plates with different thicknesses and alloy compositions at different temperatures. The algorithm matches the real-time temperature data with the elastic modulus data in the corresponding temperature interval in the database, combines the actual thickness and alloy type of the aluminum plate, and dynamically corrects the initial elastic modulus according to the "temperature-elastic modulus" correlation formula (for example, for 3003 aluminum plate, the elastic modulus is reduced by 0.5% for every 10°C temperature rise). Finally, the temperature-corrected elastic modulus is output, and the temperature-corrected stress value is obtained by substituting it into the theoretical stress value calculation formula. Considering the interfacial effect of the coating and the substrate, the model introduces the coating adhesion coefficient (value from the feature library), and when the calculated theoretical stress exceeds the coating adhesion threshold, the interfacial slip factor (0.8) is automatically introduced to correct the strain calculation result. For example, the theoretical strain = 0.001, the actual strain after interface correction = 0.001 x 0.8 = 0.0008 to reflect the impact of coating peeling risk on overall strain, combined with the geometric characteristics of the aluminum plate, the model decomposes the overall displacement increment into gradient displacement along the width direction, calculates the strain value of each micro-element body through finite element mesh division, and finally generates a global strain distribution map, where the strain value of the edge area needs to be superimposed with the additional strain caused by the velocity difference. After calculation, the model outputs the actual strain increment of each area, and the material deformation analysis module refreshes the pulling force command in real time according to the conversion relationship between strain and pulling force (F = σ x A, where A is the contact area of the pulling clamp), ensuring that the pulling force always matches the deformation demand of the material, laying a precise force value foundation for subsequent proportional distribution of traction force according to distance.

[0016] The clamping pre-deformation unit 1 includes a spatial force field reconstruction module, which distributes the traction force according to the distance proportion of each traction clamp from the center line of the roll-coated hyperbolic aluminum plate, including: After the material deformation analysis module completes the initial calculation of the pulling force command, the spatial force field reconstruction module needs to distribute the traction force according to the distance of each traction clamp from the center line of the aluminum plate. This process is the core of achieving uniform stress distribution in longitudinal large curvature forming, not only connecting the pulling force calculation logic based on strain increment in the previous text, but also ensuring the deformation of the edge area and the central area through nonlinear force field design, providing a stable stress foundation for subsequent deviation correction. First of all, the definition of the center line of the roll-coated hyperbolic aluminum plate is clear: taking the initial position of the aluminum plate entering the stretching machine as the reference, the midline of the two side edges of the aluminum plate is identified by the visual positioning system. This line runs through the entire forming area along the length direction of the aluminum plate, serving as the reference axis of the spatial position (denoted as X axis). For example, for an aluminum plate with a width of 2m, the center line is located 1m away from both sides of the edge. The measurement zero point of the laser ranging sensor is calibrated to this axis. When the distance value is obtained by the laser ranging sensor, the laser sensor on each traction clamp base emits a laser beam perpendicular to the center line to measure the straight-line distance (denoted as d, unit: m) between the traction clamp execution end and the center line in real time. After filtering processing (removing the jump values caused by mechanical vibration), the measurement data is transmitted to the spatial force field reconstruction module to form a spatial position matrix of each clamp (such as [ , ,..., ] n is the number of clamps). The detailed steps to create a nonlinear pulling force distribution map are as follows, integrating the distance-pulling force dynamic mapping mechanism: Taking the traction clamp at the center line (d = 0) as the reference point, the average pulling force calculated by the material deformation analysis module is set as the reference pulling force (such as 20000N), which ensures that the tensile stress in the central area matches the theoretical strain. Based on the edge effect theory in material mechanics, an exponential nonlinear coefficient k = e^( ), where a is a material characteristic coefficient (0.8 for 3003 aluminum plate ), d is the distance between the clamping jaw and the center line, when d increases, the value of k increases exponentially, which gradually expands the increase of the pulling force in the edge area, and the non-linear growth characteristics can avoid local tearing caused by sudden changes in pulling force. The aluminum plate width direction is divided into three regions: the near-center region (d≤0.5m), the transition region (0.5m The nonlinear coefficient of each clamping jaw is calculated by substituting the distance value d of each clamping jaw into the formula When each traction clamping jaw applies a pulling force according to the target pulling force in the map, the clamping jaw farther from the center line (i.e., the edge region) applies a greater pulling force, and the pulling force increases exponentially with distance. Thus, a gradient stress field is formed inside the aluminum plate, gradually increasing from the center to the edge. This stress distribution is completely matched with the strain gradient required for the longitudinal large curvature forming of the hyperbolic aluminum plate. The edge region needs to withstand greater plastic deformation, and the gradient stress field provides a continuous and controllable stretching driving force for it, avoiding insufficient forming due to insufficient stress or cracking due to stress concentration. The speed-lift dual-dimension control formed by the speed coordination mechanism in the previous text ensures uniform forming of the aluminum plate, and the generated nonlinear pulling force distribution map is transmitted to the execution end of each traction clamping jaw through a real-time communication protocol. The force sensor built into the clamping jaw compares the actual pulling force with the target value in a closed loop to ensure that the actual effect of the gradient stress field is consistent with the theoretical design, providing a stable force field basis for subsequent strain deviation monitoring.

[0017] When the actual strain increment of the edge of the roll-coated hyperbolic aluminum plate deviates from the target value by more than the preset deviation threshold, the deviation area is located and the edge traction speed and pulling force of the traction clamping jaw in the deviation area are increased. The multi-modal fusion detection array for locating the deviation area includes: ​On the basis of the spatial force field reconstruction module establishing a gradient stress field, in order to timely find the local deformation abnormality caused by material unevenness or force field fluctuation in the stretching process, the multi-modal fusion detection array needs to be positioned to the deviation area, which is not only the monitoring of the actual effect of the gradient stress field, but also provides accurate spatial coordinates for subsequent targeted adjustment of the traction parameters, and forms a closed-loop control with the force field distribution logic in the foregoing, the specific implementation is as follows: The multi-modal fusion detection array is composed of an infrared thermal imager and a laser interferometer, and the two work cooperatively according to a preset time synchronization signal to capture the abnormal changes of the aluminum plate from two dimensions of temperature and geometric shape. The infrared thermal imager is installed 2 m above the stretching machine to perform full-domain scanning on the surface of the double-curved aluminum plate at an angle of 45°, and capture the temperature field abnormal distribution graph. When the aluminum plate is uniformly stretched, the surface temperature will present a gentle gradient distribution due to plastic deformation. When stress concentration occurs locally, the plastic deformation of the region will intensify, and the temperature will abnormally rise. The thermal imager compares the current frame with the average temperature field of the previous 5 frames through a frame-to-frame temperature difference comparison algorithm, marks the region with an absolute temperature difference ≥ 3 ℃ as a temperature abnormal region, and outputs the two-dimensional pixel coordinates thereof. The simultaneously started laser interferometer emits a wavelength of 632.8 nm helium-neon laser to perform point-by-point scanning on the surface of the aluminum plate, with a scanning density of 10 points / mm², and calculates the relative displacement of each point in real time, and then converts the local curvature change amount. When the aluminum plate is normally stretched, the longitudinal curvature of the aluminum plate should change smoothly along the preset trajectory. If the curvature change rate (the ratio of the curvature difference between two adjacent points to the distance) of a region exceeds 0.5 / m², it is determined as a curvature mutation region. The laser interferometer outputs the two-dimensional coordinates (based on the laser scanning coordinate system) of the curvature mutation region, which forms a complementary monitoring with the temperature abnormal region. When the temperature abnormal region and the curvature mutation region are subjected to spatial superposition operation through an image processing algorithm, first, the coordinate systems are unified: The pixel coordinates of the infrared thermal imager and the scanning coordinates of the laser interferometer are calibrated (error ≤ 1 mm) through a calibration plate, and are converted to a unified coordinate system with the center line of the aluminum plate as the X axis and the stretching direction as the Y axis. The morphological erosion and dilation algorithm is used to smooth the boundaries of the two regions, and the isolated noise points are removed. Finally, the intersection of the two regions is calculated. When a region simultaneously satisfies temperature abnormality and curvature mutation, it is determined as a deviation region, and through three-dimensional coordinate conversion, combined with the Z-axis height data of the laser interferometer, the three-dimensional coordinate positioning data of the region is output. This multi-modal fusion positioning method not only captures the stress concentration state inside the material through temperature abnormality, but also confirms the abnormal deformation of the external shape through curvature mutation. The spatial superposition of the two ensures the accuracy of the deviation region positioning, avoids the misjudgment that may occur in a single mode, and outputs the three-dimensional coordinate data, which provides accurate action point reference for subsequent improvement of the traction speed and the downforce of the deviation region, so that the adjustment measures can accurately act on the abnormal region, and forms a dynamic response mechanism with the gradient stress field control, which together guarantees the uniform forming of the aluminum plate.

[0018] The edge traction speed of the deviation area traction gripper is raised, including: After positioning the deviation area by the multi-modal fusion detection array and obtaining its three-dimensional coordinate data, the edge traction speed of the traction gripper in the area needs to be raised in a targeted manner. This process is a dynamic response to the deformation anomaly of the deviation area, which not only connects the precise positioning result in the previous text, but also ensures the coordination of the overall stretching through the correlation control with the central stretching speed, avoiding new stress imbalance caused by local speed adjustment. The specific implementation is as follows: When the speed compensation controller receives the three-dimensional coordinate positioning data of the deviation area, it first determines the corresponding target traction gripper number of the area through the coordinate mapping algorithm, and immediately activates the speed adjustment module of these grippers. In terms of maintaining correlation with the central stretching speed reference, the system adopts a dynamic proportional locking mechanism: The speed compensation controller receives the central stretching speed data in real time, and sets a temporary proportional coefficient based on the curvature characteristics of the deviation area. For the curvature mutation area, the temporary proportional coefficient is increased by 10-30% on the basis of the original proportional coefficient, so that the edge traction speed is always a fixed multiple of the central stretching speed. For example, when the central stretching speed rises to 3.0 m / s, the speed reference value of the target traction gripper is calculated at 1.3 times, which is 3.9 m / s, ensuring that the stretching rhythm of the edge and the center remains matched, avoiding wrinkles or tears caused by speed disconnection. At the same time, the system compares the proportional relationship between the edge speed and the central speed every 5 ms, and if the deviation exceeds 2%, the temporary proportional coefficient is immediately fine-tuned to maintain the stability of the dynamic correlation. The speed upgrade instruction realizes the process of stepless speed adjustment through a smooth acceleration curve generator, which integrates the gradual force generation logic of bionics: The curve generator first obtains the difference between the current edge pulling speed and the target speed, and automatically selects the acceleration curve type according to the difference size. When the difference is ≤0.5 m / s, a sinusoidal acceleration curve (the acceleration first increases and then decreases) is used, and when the difference is >0.5 m / s, an S-shaped acceleration curve (including a starting section, a uniform acceleration section, and a deceleration section) is used to ensure the smoothness of the acceleration process. Taking the S-shaped curve as an example, the total acceleration time is divided into three stages, each occupying 1 / 3 of the time. The starting section (the acceleration is linearly increased from 0 to the maximum acceleration 0.5 m / s²), the uniform acceleration section (the maximum acceleration is maintained), and the deceleration section (the acceleration is linearly decreased from the maximum to 0). Through this three-stage transition, mechanical shocks caused by sudden acceleration are avoided. During the acceleration process, the curve generator outputs an instantaneous speed command every 1 ms, and the target traction gripper servo motor adjusts the speed in real time according to the command. The pulse width modulation is used to realize stepless switching of the speed, ensuring the continuity of the speed change, and the speed difference between adjacent moments is ≤0.01 m / s. This makes the aluminum plate in the deviation area smoothly transition from abnormal state to normal trajectory, and forms a quick response closed loop of discovery and adjustment with the deviation area positioning, laying a stable speed foundation for subsequent targeted improvement of the down-draw force.

[0019] The use of roll-coated double-curved aluminum plates to improve the down-draw force in the deviation area includes: After completing the improvement of the edge pulling speed of the traction gripper in the deviation area, the down-draw force in this area needs to be improved simultaneously to match the deformation requirements after speed adjustment. This process is a precise control of the mechanical state of the deviation area, which not only coordinates with the speed compensation logic, but also dynamically matches the tensile force and material yield characteristics through micro-dislocation monitoring, ensuring that the aluminum plate does not undergo excessive stretching or tearing when correcting deformation. The piezoelectric crystal array is a distributed monitoring network composed of dozens of piezoelectric sensors, installed on the end surface of the traction gripper in contact with the aluminum plate, and can convert the small stress changes caused by aluminum plate deformation into electrical signals. The sampling frequency reaches 1 kHz, which can capture the internal mechanical disturbance of the material in real time. The dislocation density change curve is a defect in the arrangement of atoms in the metal crystal. When the aluminum plate is stretched, the dislocation will move and proliferate, and the change in its density (the number of dislocations per unit volume) directly reflects the degree of plastic deformation of the material. The curve takes time as the horizontal axis and the dislocation density (the number of dislocations per unit volume) as the vertical axis. ) is the longitudinal axis, generated by the conversion of the electrical signal of the piezoelectric crystal array, the greater the slope indicates the more intense deformation, the crystal slip direction is the direction of the relative sliding of the atomic plane in the metal crystal along a certain crystal plane, which is determined by the crystal structure of the material itself, under the action of tensile stress, dislocation movement accumulates along this direction, and finally forms macroscopic deformation, the stepped force increasing pulse indicates that the amplitude of the pulling force is not continuously linearly increased, but the force signal is increased in steps according to the preset step, the duration of each step matches the periodicity of dislocation movement, avoiding the impact on the crystal lattice caused by sudden changes in force value, after the target traction clamp in the deviation area is positioned, the piezoelectric crystal array immediately starts monitoring, the electrical signals output by each sensor in the array are amplified and filtered, and then input into the dislocation analysis algorithm, through comparison with the standard dislocation-stress corresponding relationship of the aluminum plate material, the dislocation density value at each time is converted, the continuous dislocation density value is fitted into a smooth curve with time as the axis, and the dislocation movement speed is calculated through the first derivative of the curve, combined with the tensile direction of the aluminum plate and crystallographic data, the spatial distribution of dislocation density is converted into a three-dimensional motion trajectory, which intuitively presents the migration path of dislocation inside the aluminum plate, based on the dislocation motion trajectory, the following steps are taken to generate the force increasing waveform atlas, identify the key parameters of dislocation movement, the main direction of the trajectory (compared with the crystal lattice slip direction, the included angle θ is determined), the peak speed (the fastest moment of dislocation movement), and the periodic fluctuation frequency (velocity oscillation caused by lattice resistance), taking the current pulling force of the target clamp as the benchmark, setting the initial amplitude ratio, determining the total amplitude according to the peak speed of the trajectory, segmenting according to the slope of the dislocation density curve, using large steps (800N per step) in the slope increasing stage (deformation acceleration) and small steps (300N per step) in the slope gentle stage (deformation stability), synchronizing with the periodic fluctuation frequency of dislocation movement (such as a fluctuation period of 100ms, the interval is set to 100ms), ensuring that the force application time of each step matches the time when dislocation breaks away from the lattice resistance, by adjusting the starting time of the step, the rising edge of the force increasing pulse is synchronized with the peak value of dislocation movement in the crystal lattice slip direction, and the step height, interval, total amplitude and other parameters are integrated into the visual force increasing waveform atlas, with time as the horizontal axis and pulling force as the vertical axis, as the command template for pulling force adjustment, according to the force increasing waveform atlas, the force control system of the traction clamp outputs a stepped force increasing pulse through a servo valve, the specific process is as follows: Each step applies a preset force value and duration, for example, the first step increases from 20000N to 20800N and maintains for 100ms, the second step increases to 21600N and maintains for 80ms (due to the acceleration of dislocation movement frequency), until the target pulling force is reached, the real-time strain data of the aluminum plate is synchronously collected (through a laser interferometer), the current yield strength is calculated (Y ) With the increase of work hardening, when the dislocation density is saturated tends to be stable, if the actual yield strength is monitored to be faster than expected, the current step duration is automatically extended, the increase rate is reduced, if rise slowly (obstruction of dislocation movement), the interval is shortened and the step height is increased, and the dislocation is pushed to break through the lattice resistance by stronger pulling force, and finally the increase of the pulling force always maintains a dynamic ratio of 1:1.2 with the evolution process of The safety factor based on material test calibration, through this stepwise force increasing method based on micro-dislocation monitoring, the pulling force can not only accurately correct the deformation of the deviation area, but also adapt to the real-time change of the material yield strength. The speed adjustment in the previous text forms a speed-pulling force double parameter cooperation, so that the stress state of the aluminum plate in the deviation area quickly returns to the normal range, laying a stable mechanical foundation for the subsequent local strengthening traction.

[0020] When the local curvature radius of the deviation area decreases to the preset curvature radius range, the local area strengthening traction mode is started. The dynamic curvature coupling control is introduced when the local area strengthening traction mode is started, including: After completing the stepwise lifting of the pulling force in the deviation area, when the curvature radius identification sensor detects that the local curvature radius of the roll-coated hyperbolic aluminum plate decreases to the preset critical range, it means that the aluminum plate enters the critical deformation zone. At this time, the local area strengthening traction mode needs to be started, and the dynamic curvature coupling control is introduced. This process is a deep regulation of the key stage of large curvature forming, which not only undertakes the speed and pulling force adjustment of the deviation area in the previous text, but also ensures that the aluminum plate can still maintain structural uniformity under extreme deformation through multi-dimensional collaborative control. The triggered triple response mechanism is implemented as follows: First, the speed phase lock loop of the traction clamp in the deviation area is established, which takes the electromagnetic field signal of the central stretching speed as the reference, is realized through the establishment of the electromagnetic coupling link between the driving motor of the traction clamp and the main stretching machine transmission shaft, installs the Hall sensor at the end of the motor shaft, collects the electromagnetic field frequency corresponding to the edge traction speed in real time, receives the electromagnetic field reference signal of the main stretching machine transmission shaft at the same time, calculates the phase difference of the two through the phase comparator, and if the phase difference exceeds the threshold value, immediately outputs the correction current through the PID regulator to adjust the motor speed to eliminate the phase deviation. This synchronization method based on electromagnetic field signal can control the time difference between the edge traction speed and the central stretching speed within 10 microseconds, that is, form the so-called electromagnetic field level synchronization, ensure that the stretching rhythm of the deviation area completely matches the overall forming process, avoid stress concentration caused by the accumulation of small speed difference, and activate the bionic hydraulic tendon group. It is a hydraulic driving device that simulates the elastic properties of human tendon, which is composed of multiple series of elastic hydraulic cavities, filled with high viscosity hydraulic oil, and has the characteristics of stretching and power similar to tendon through dynamic adjustment of the pressure in the cavity. The stress relaxation characteristics of the roll-coated hyperbolic aluminum plate refer to the characteristics that the internal stress gradually decays over time while maintaining a constant strain. The bionic hydraulic tendon group monitors the stress change curve of the aluminum plate in real time through the pressure sensor, and automatically adjusts the pressure output of the hydraulic cavity when it identifies that the stress relaxation rate is accelerating. It generates an adaptive waveform tension that reverses the stress relaxation curve. During the rapid stress decline phase, the tension output is increased, and during the stable stress phase, the increase is reduced. Through this dynamic compensation, the influence of stress relaxation on the forming accuracy is offset. Finally, the crystal orientation modulator is started. The device can emit directional ultrasonic wave field with a frequency of 1-5 MHz, and its propagation direction is consistent with the current curvature normal of the aluminum plate, that is, perpendicular to the curvature center. When the ultrasonic wave field acts on the inside of the aluminum plate, periodic stress fluctuations will occur at the grain boundaries. This fluctuation energy will guide the originally randomly oriented grains to rotate and reorganize along the direction of ultrasonic wave propagation (i.e. the curvature normal). Specifically, the compression and sparseness of the ultrasonic wave will make the grains preferentially arrange in the direction with the lowest energy (curvature normal), just like water flow pushing stones to align along the river direction. Through the action of directional ultrasonic wave for 2-3 seconds, local brittle cracking caused by disordered grain arrangement is avoided, and the accuracy and quality of the roll-coated hyperbolic aluminum plate are ensured.

[0021] That is, according to the central stretching speed at this time, the edge traction speed of the traction clamp in the deviation area is set. The edge traction speed of the traction clamp in the deviation area is set by adopting the eddy current field synchronization technology, which includes: After starting the local area reinforced traction mode and realizing multi-dimensional coordination through dynamic curvature coupling control, in order to further improve the accuracy of the deviation area speed control, the edge traction speed needs to be set by using the eddy current field synchronization technology. This step is a deepening of the speed synchronization mechanism, which not only inherits the basic synchronization logic of the speed phase-locked loop, but also realizes more fine dynamic matching by capturing the plastic flow state inside the material, ensuring that the traction speed completely matches the micro deformation rhythm of the aluminum plate, and after the reinforced traction mode is activated, the vortex sensor array embedded at the end of the traction clamp starts working immediately, which is composed of multiple high-frequency vortex probes. During the stretching process of the aluminum plate, dislocation movement occurs inside, that is, irregular displacement of atomic arrangement in the crystal structure. This micro movement is accompanied by redistribution of electric charge, which will generate weak electromagnetic field disturbance inside the material. The vortex sensor array can sensitively capture these disturbance signals and convert them into voltage fluctuation signals, which can reflect the intensity and rate of dislocation movement in real time, and indirectly represent the plastic flow state inside the aluminum plate. The process of inputting the electromagnetic field disturbance signal into the bit compensation algorithm to generate the speed correction waveform reflects the accurate conversion from micro signal to macro control instruction. Firstly, the original disturbance signal is filtered to extract the characteristic frequency component related to dislocation movement. Then, the time domain signal is converted into a frequency domain spectrum through Fourier transform, and the main peak frequency is identified. The frequency is positively correlated with the dislocation movement speed. The bit compensation algorithm is based on a pre-set frequency-speed mapping model to calculate the deviation value between the current plastic flow rate and the target rate, and generate a corresponding speed correction waveform according to the deviation. The correction waveform uses a sine-modulated pulse signal, whose amplitude is proportional to the deviation size, and the frequency is consistent with the characteristic frequency of the disturbance signal, ensuring that the correction instruction can accurately match the dynamic changes of plastic flow. Through this speed correction waveform, the edge traction speed of the traction clamp in the deviation area and the plastic flow rate inside the aluminum plate form a phase-locked loop control. The reference signal of the phase-locked loop is taken from the electromagnetic field disturbance characteristic frequency captured by the vortex sensor array (representing the plastic flow rate), and the feedback signal is the current edge traction speed of the traction clamp (real-time collected by the encoder). The phase-locked loop controller continuously compares the frequency and phase of the two signals. When there is a deviation between the feedback signal and the reference signal, the edge traction speed is immediately adjusted through the correction waveform to make the change rhythm of the edge traction speed completely synchronized with the fluctuation of the plastic flow rate, just like two gears tightly engaged, realizing the non-lagging following of plastic flow to traction speed. After the main stretching machine enters the pressure maintaining stage, the system keeps the current down force of all traction clamps unchanged, and maintains the synchronization state of speed and plastic flow through continuous phase-locked loop control until the forming stress inside the aluminum plate is gradually released through microstructure reorganization. At this time, the edge auxiliary traction process is completed. This whole process from micro disturbance monitoring to macro speed regulation forms a closed-loop fine control logic, which together with the dynamic curvature coupling control guarantees the precision and stability of the roll-coated double-curved aluminum plate in longitudinal large-curvature forming.

[0022] In the application, the pre-deformation unit 1 is clamped, the main stretching machine is started, the clamping jaw is pulled down at the basic speed, and the dynamic proportional relationship of the edge and the central stretching speed is established, in the stretching process, when the displacement increment reaches the threshold value, the traction force is distributed according to the distance proportional to the center line, the pull-down force is updated in real time, when the strain deviation exceeds the limit, the multi-mode array positioning deviation area is positioned, the traction speed and the pull-down force of the area are improved, when the local curvature radius reaches the critical range, the enhanced traction mode is started, the speed and the plastic flow are locked in phase, and the grain orientation is controlled, and the traction force is maintained in the pressure maintaining stage to release the stress, the longitudinal large curvature forming precision of the roll-coated double-curved aluminum plate is improved, the wrinkles and cracks are reduced, and the application is suitable for high-precision double-curved aluminum plate processing.

[0023] The second purpose of the application is to provide a method for realizing the edge auxiliary traction system for the longitudinal large curvature forming of the roll-coated double-curved aluminum plate. S1, when the main stretching machine starting signal is triggered, the pull-down action of all clamping jaws is activated synchronously, the dynamic proportional relationship of the edge traction speed and the central stretching speed is established through the speed instruction generator, and the initial position of the clamping jaw is lower than the mold plane to form a pre-deformation area; S2, when the longitudinal stretching machine displacement increment reaches the threshold value, the material deformation analysis module is called to convert the displacement into strain increment, and the gradient traction force distribution atlas is generated based on the spatial position data; S3, when the strain deviation exceeds the threshold value, the multi-mode positioning is started, the speed phase-locked loop and the grain orientation modulator are triggered to realize the microscopic cooperative control; S4, the gradient traction force is maintained in the pressure maintaining stage, and the staged unloading program is started through the grain boundary recombination signal monitoring.

[0024] The basic principles, main features and advantages of the application are shown and described. It should be understood by those skilled in the art that the application is not limited by the above examples, the above examples and descriptions in the specification are only preferred examples of the application, and are not used to limit the application, various changes and improvements of the application can be made without departing from the spirit and scope of the application, and these changes and improvements all fall within the scope of the claimed application. The scope of protection of the application is defined by the appended claims and their equivalents.

Claims

1. A roll-coating double-curved aluminum plate longitudinal large-curvature forming edge auxiliary traction system, comprising a clamping pre-variation unit (1), when a main stretching machine starting signal triggers, all traction clamping jaws start a downward pulling action at a preset basic speed, and a mathematical relationship between the edge traction speed and the central stretching speed is set, characterized in that, Also included are: In the main stretching process, when the displacement increment of the longitudinal stretcher reaches the preset displacement threshold, the down force of each traction jaw is automatically updated according to the strain increment of the roll-coated double-curved aluminum plate, and the traction force is distributed in proportion to the distance of each traction jaw from the center line of the roll-coated double-curved aluminum plate. When the actual strain increment of the roll-coated double-curved aluminum plate monitored in real time deviates from the target value by more than the preset deviation threshold, the deviation area is located and the edge traction speed and down force of the traction jaw in the deviation area are increased. When the local radius of curvature of the deviation area decreases to the preset radius of curvature range, the local area strengthening traction mode is started, that is, the edge traction speed of the traction jaw in the deviation area is set according to the current central stretching speed. After the main stretcher enters the pressure maintaining stage, the down force of all traction jaws is maintained until the forming stress is released and the edge auxiliary traction is completed.

2. The roll-coated double-curved aluminum panel longitudinal large-curvature forming edge-assisted pulling system according to claim 1, characterized in that: The clamping pre-forming unit (1) includes a speed relationship setting module for setting the mathematical relationship between the edge traction speed and the central stretching speed, which includes: A traction jaw speed command generator is established, which receives the transmission shaft speed signal of the main stretcher in real time, converts the transmission shaft speed signal into central stretching speed data through a signal converter, and generates an edge traction speed reference value through a proportional operator. The proportional operator has a material flowability compensation algorithm built-in, which dynamically adjusts the proportional coefficient according to the extension characteristics of the transmission shaft speed signal, so that the edge traction speed compensates for the material flow lag effect.

3. The roll-coated double-curved aluminum panel longitudinal large-curvature forming edge-assisted pulling system according to claim 1, characterized in that, The clamping pre-forming unit (1) includes a material deformation analysis module for automatically updating the down force of each traction jaw according to the strain increment of the roll-coated double-curved aluminum plate, which includes: When the cumulative displacement change of the longitudinal stretcher is monitored, a preset material stress-strain conversion model is triggered, which integrates an elastic modulus database of the roll-coated double-curved aluminum plate, a coating adhesion feature library, and a real-time temperature compensation algorithm. The displacement increment of the longitudinal stretcher is converted into the actual strain increment of the roll-coated double-curved aluminum plate through multi-physical field coupling calculation and output to the material deformation analysis module for real-time refresh of the down force command.

4. The roll-coated double-curved aluminum panel longitudinal large-curvature forming edge-assisted pulling system according to claim 1, characterized in that: The clamping pre-forming unit (1) includes a spatial force field reconstruction module for distributing the traction force in proportion to the distance of each traction jaw from the center line of the roll-coated double-curved aluminum plate, which includes: The distance values of each traction jaw from the center line of the roll-coated double-curved aluminum plate are obtained through a laser ranging sensor installed on the traction jaw base. The spatial force field reconstruction module creates a nonlinear tension distribution map according to the distance values, so that a gradient stress field is formed in the edge area of the roll-coated double-curved aluminum plate. The nonlinear tension distribution map is transmitted to the execution end of each traction jaw in real time.

5. The roll-coated double-curved aluminum panel longitudinal large-curvature forming edge-assisted pulling system according to claim 1, characterized in that: The deviation area positioning device uses a multi-modal fusion detection array, which includes: An infrared thermal imager captures the abnormal temperature distribution of the roll-coated double-curved aluminum plate surface, obtains a temperature anomaly area, synchronously measures the local curvature change with a laser interferometer, obtains a curvature mutation area, and performs spatial superposition operation on the temperature anomaly area and the curvature mutation area through an image processing algorithm to output three-dimensional coordinate positioning data of the deviation area.

6. The roll-coated double-curved aluminum panel longitudinal large-curvature forming edge-assisted pulling system according to claim 5, characterized in that: The edge traction speed of the traction jaw in the deviation area is increased, which includes: When receiving the three-dimensional coordinate positioning data, the speed compensation controller is immediately activated to send a speed upgrade instruction to the target traction clamp, which is adjusted by a smooth acceleration curve generator to eliminate mechanical impact while maintaining the association with the central stretching speed reference.

7. The roll-coated double-curved aluminum panel longitudinal large-curvature forming edge-assisted pulling system according to claim 5, characterized in that: The roll-coated double-curved aluminum plate is used to enhance the deviation area and the downward force includes: When the target traction clamp in the deviation area is positioned, the dislocation density change curve of the roll-coated double-curved aluminum plate is captured in real time by a piezoelectric crystal array, a dislocation motion trajectory is generated, a force enhancement waveform atlas is generated based on the dislocation motion trajectory, and a step-shaped force enhancement pulse that is in phase with the lattice slip direction of the roll-coated double-curved aluminum plate is output according to the force enhancement waveform atlas, so that the downward force amplitude matches the yield strength evolution process of the roll-coated double-curved aluminum plate.

8. The roll-coated double-curved aluminum panel longitudinal large-curvature forming edge-assisted pulling system according to claim 7, characterized in that: The dynamic curvature coupling control is introduced when the local area reinforced traction mode is started, including: When the curvature radius identification sensor detects that the roll-coated double-curved aluminum plate enters the critical deformation zone, a triple-response mechanism is triggered: The speed phase-locked loop of the traction clamp in the deviation area is established to form electromagnetic field level synchronization between the edge traction speed of the traction clamp in the deviation area and the central stretching speed, and the bionic hydraulic muscle group is activated, which generates an adaptive waveform tension according to the stress relaxation characteristics of the roll-coated double-curved aluminum plate, and finally the crystal orientation modulator is started to guide the grain of the roll-coated double-curved aluminum plate to preferentially arrange along the curvature normal direction through directional ultrasonic field.

9. The roll-coated double-curved aluminum panel longitudinal large-curvature forming edge-assisted pulling system according to claim 8, characterized in that: The edge traction speed of the traction clamp in the deviation area is set by using eddy current field synchronization technology, including: After the reinforced traction mode is activated, the end-embedded eddy current sensor array is executed on the traction clamp to capture electromagnetic field disturbance signals generated by the dislocation motion inside the roll-coated double-curved aluminum plate in real time, and the electromagnetic field disturbance signals are input into the site compensation algorithm to generate a speed correction waveform, so that the edge traction speed of the traction clamp in the deviation area and the internal plastic flow rate of the roll-coated double-curved aluminum plate form a phase-locked loop control.

10. A method for implementing an edge assisted traction system for the longitudinal large curvature forming of a roll-coated double-curved aluminum panel comprising the roll-coated double-curved aluminum panel of any one of claims 1-9, characterized in that: The method includes the following steps: S1, when the main stretching machine starting signal is triggered, the downward action of all traction clamps is activated synchronously, the dynamic proportional relationship between the edge traction speed and the central stretching speed is established through the speed instruction generator, and at the same time, the initial position of the traction clamp is lowered below the mold plane to form a pre-deformation zone; S2, when the displacement increment of the longitudinal stretcher reaches the threshold value, the material deformation analysis module is called to convert the displacement into strain increment, and a gradient traction force distribution atlas is generated based on the spatial position data; S3, when the strain deviation exceeds the threshold value, the multi-modal positioning is started, the speed phase-locked loop and the grain orientation modulator are triggered to realize microcosmic cooperative control; S4, the gradient traction force is maintained during the pressure maintaining stage, and the staged unloading program is started by monitoring the grain boundary recombination signal.

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