A friction stir welding online testing method, system, product and medium

Abstract

A method, system, product, and medium for online testing of friction stir welding. The method includes: obtaining the motion trajectory of the welding tool, identifying the turning segments, and simultaneously calculating the turning angle of each turning segment; for each turning segment, calculating the difference in inner and outer path lengths based on the welding tool diameter and the turning angle, thereby obtaining an action difference coefficient that characterizes the degree of uneven force applied to the material, and determining the compensation start time and compensation angle in combination with the turning segment position; when entering the real-time turning segment, obtaining the compensation angle of the previous turning segment and the remaining distance between the two segments, calculating the remaining compensation amount of the previous turning segment using a decaying exponential function, and determining whether to increase or decrease the real-time compensation angle based on the similarities and differences in the directions of the previous turning segment and the real-time turning segment, ultimately obtaining a real-time corrected compensation angle to control the welding tool posture. Implementing the technical solution provided by this application improves the uniformity of weld quality during friction stir welding on complex curved trajectories.

Description

Technical Field

[0001] The present application relates to the field of welding, and in particular to an online testing method, system, product and medium for friction stir welding. Background Art

[0002] With the development of modern industrial manufacturing technology, the problem of joining dissimilar metals has become increasingly prominent. As a solid-state joining technology, friction stir welding (FSW) offers advantages such as minimal deformation, low residual stress, energy conservation, and environmental protection. It has been widely used in aerospace, rail transportation, shipbuilding, and other fields.

[0003] In related technologies, welding tool posture adjustment is often used to improve welding quality. This approach involves conducting extensive process experiments to determine optimal welding parameter combinations for different welding conditions and establishing a comprehensive welding parameter database. During the actual welding process, the corresponding welding parameters are retrieved from the database based on the workpiece's shape characteristics and material properties. Furthermore, the welding parameters are fine-tuned in real time based on factors such as the temperature field distribution and weld formation during welding to ensure consistent welding quality.

[0004] However, in the related art, fixed welding parameter settings will cause obvious problems when encountering curved trajectory segments. Due to the different path lengths inside and outside the curved segment, the outer material needs to fill a larger space in the same amount of time, and the heat input obtained is the same as the inner side, which makes the outer area prone to defects such as lack of fusion and insufficient strength. What is more serious is that when multiple curved segments are adjacent, the heat accumulation and plastic deformation generated by the previous curved segment will affect the temperature field distribution and material flow state of the subsequent curved segments. This superposition effect of heat and stress makes the welding process of subsequent curved segments more complicated, and the fixed parameter adjustment method cannot adapt to this dynamically changing working condition, which ultimately leads to uneven spatial distribution of weld quality, especially in the continuous curved segment area. Summary of the Invention

[0005] The present application provides an online testing method, system, product and medium for friction stir welding, which are used to improve the uniformity of weld quality during friction stir welding under complex curved trajectories.

[0006] In a first aspect of the present application, a friction stir welding online testing method is provided, the method comprising:

[0007] The motion trajectory of the welding tool is obtained, the curvature change rate of each point of the motion trajectory is calculated, and the trajectory segment consisting of adjacent points whose curvature change rate exceeds a preset curvature threshold is marked as a turning segment. The turning angle of each turning segment is calculated. For each turning segment, the path length difference between the inner and outer sides of the turning and the action difference coefficient reflecting the uneven force on the inner and outer materials are calculated based on the welding tool diameter and the turning angle. The compensation start time is determined based on the position of the turning segment, and the compensation tilt angle is calculated based on the steering angle and the action difference coefficient. When entering the real-time turning segment, the previous compensation tilt angle of the previous turning segment and the remaining distance between the previous turning segment and the real-time turning segment are obtained. The remaining compensation amount caused by the previous turning segment is calculated using a decaying exponential function, and it is determined whether the previous turning segment and the real-time turning segment are turning in the same direction. If so, the real-time compensation tilt angle of the real-time turning segment is increased by the remaining compensation amount to obtain a real-time corrected compensation tilt angle. If not, the real-time compensation tilt angle is reduced by the remaining compensation amount to obtain a real-time corrected compensation tilt angle. The posture of the welding tool is controlled based on the real-time corrected compensation tilt angle.

[0008] In the above-described embodiment, by identifying turning segments in the motion trajectory and dynamically adjusting the welding tool's posture, the problem of uneven flow between the inner and outer sides of curved trajectory welding caused by different path lengths is addressed. First, turning segments are identified using the curvature change rate, and the difference in path length between the inner and outer sides is calculated based on the turning angle and tool diameter. This geometric analysis ensures accurate understanding of the characteristics of the turning segments. Then, by calculating the action difference coefficient, the degree of uneven force applied to the inner and outer materials is quantified. Based on this, a compensation angle is determined, tilting the welding tool at a specific angle to increase the extrusion pressure and heat input in the outer region, thereby balancing the material flow inside and outside. More importantly, the interaction between multiple turning segments is taken into account, and the residual compensation amount of the preceding turning segment is calculated using a decaying exponential function. Different overlay strategies are then applied based on the differences in turning directions. When adjacent turning segments are in the same direction, the real-time compensation angle is increased to enhance the compensation effect; when the turning directions are opposite, the compensation angle is reduced to avoid overcompensation. This dynamic compensation mechanism, which takes into account the effects of heat accumulation and stress superposition, can accurately cope with various working conditions in complex curved trajectories, especially in the case of multiple consecutive turning sections. By controlling the posture of the welding tool, the uniformity of the weld quality during stir friction welding in complex curved trajectories is improved.

[0009] In conjunction with some embodiments of the first aspect, in some embodiments, when entering a real-time turning segment, obtaining a preceding compensation inclination angle of a preceding turning segment and a remaining distance between the preceding turning segment and the real-time turning segment, and calculating a remaining compensation amount caused by the preceding turning segment using a decaying exponential function specifically includes:

[0010] When a point is detected where the axial force and torque in the remaining path decrease simultaneously and the decrease rate exceeds the corresponding decrease rate threshold, it is marked as the starting point of the gap area; after the starting point of the gap area appears, when a point is detected where the axial force and torque increase simultaneously, it is marked as the end point of the gap area; the remaining compensation amount brought by the preceding steering section is calculated by the attenuation exponential function, and the attenuation coefficient of the attenuation exponential function in the gap area is set to the preset maximum attenuation coefficient.

[0011] In the above embodiment, gap regions are identified by real-time monitoring of the changing characteristics of axial force and torque. The impact of gaps on the transmission of the compensation effect is considered in the compensation calculation. By setting the attenuation coefficient of the attenuation exponential function to its maximum value in the gap region, the rapid decay of the compensation effect in the gap is simulated. This compensation transmission mechanism, which considers the influence of gaps, effectively addresses situations where the compensation effect in the preceding steering section is blocked by gaps, preventing the unreasonable continuation of the compensation effect after the gap, thereby improving the uniformity of weld quality during friction stir welding on complex curved paths.

[0012] In conjunction with some embodiments of the first aspect, in some embodiments, after detecting that the axial force and torque rise simultaneously and marking it as the end point of the gap area, the method further includes:

[0013] When the length of the gap area is less than the minimum value in the preset gap area threshold range, the disturbance amplitude is calculated according to the gap area length, and the welding tool is controlled to perform a lateral disturbance according to the disturbance amplitude; when the length of the gap area is within the gap area threshold range or equal to the boundary value of the gap area threshold range, the speed increase value is calculated according to the gap area length, and the welding tool is controlled to increase the speed according to the speed increase value; when the length of the gap area is greater than the maximum value in the preset gap area threshold range, the position information of the gap area is recorded, a defect warning signal is issued, and the welding tool is controlled to return to the starting point of the gap area for repair welding and then move forward along the motion trajectory again.

[0014] In the above embodiment, differentiated treatment strategies are implemented based on gap size. For small gaps, lateral disturbance is used to increase material flow and mixing; for medium gaps, the rotation speed is increased to increase heat input and plasticization; and for large gaps, a return repair method is used to eliminate defects. This gap-size-based hierarchical treatment mechanism selects the optimal treatment solution for gaps with different characteristics, avoiding overtreatment of small defects while ensuring sufficient repair of large defects, thereby improving the uniformity of weld quality during friction stir welding on complex curved paths.

[0015] In conjunction with some embodiments of the first aspect, in some embodiments, before controlling the posture of the welding tool according to the real-time corrected compensation tilt angle, the method further includes:

[0016] The three-dimensional contour data of the workpiece surface within the preset welding point monitoring area in front of and below the welding point is obtained; the displacement deviation of the welding point in the normal direction of the workpiece and the actual normal vector of the workpiece surface at the contact point are calculated based on the three-dimensional contour data; and the real-time correction compensation inclination angle is secondary corrected based on the displacement deviation and the actual normal vector.

[0017] In the above-described embodiment, by calculating the normal displacement deviation and the actual normal vector, local geometric features of the workpiece surface are obtained in the event of possible plastic changes on the workpiece surface, and secondary corrections to the compensation tilt angle are made accordingly. This dynamic correction mechanism based on real-time surface features can promptly address posture deviations caused by workpiece deformation. This is particularly true during the welding of large and complex components. By adjusting the tool posture by tracking the workpiece surface features, the uniformity of the weld quality during friction stir welding on complex curved trajectories is improved.

[0018] In conjunction with some embodiments of the first aspect, in some embodiments, after performing a secondary correction on the real-time corrected compensation tilt angle according to the displacement deviation and the actual normal vector, the method further includes:

[0019] A vibration signal during the welding process is obtained and a spectrum analysis is performed on the vibration signal; a vibration suppression reaction force is calculated based on the vibration signal and an active damping device is controlled to apply the vibration suppression reaction force; when it is detected that the amplitude of the vibration signal exceeds a preset instability vibration threshold, the spindle speed of the welding tool is reduced and the vibration suppression reaction force is increased according to the frequency of the vibration signal; when the amplitude of the vibration signal still exceeds the instability vibration threshold after the spindle speed is reduced, an abnormal vibration alarm signal is generated.

[0020] In the above-described embodiment, vibration control during the welding process is achieved by real-time monitoring of vibration signals and implementing a multi-stage suppression strategy. First, vibration characteristics are identified through spectral analysis, and a suppressive reaction force is applied via an active damping device. When high vibration levels are detected, a combination of speed reduction and damping force is employed to suppress the vibrations. If vibration levels continue to exceed the specified limit, an alarm is issued. This progressive vibration control mechanism selects the appropriate suppression strategy for varying vibration intensities. This is particularly true for welding on complex curved trajectories. By controlling the vibration state, the uniformity of the weld quality during friction stir welding is improved.

[0021] In conjunction with some embodiments of the first aspect, in some embodiments, determining the compensation start time according to the position of the turning section specifically includes:

[0022] The stress and strain distribution data of the workpiece surface are obtained and the maximum stress value of each turning section is identified; the compensation starting point of the turning section is determined according to the maximum stress value of the turning section; and the compensation starting time corresponding to the turning section is obtained according to the compensation starting point.

[0023] In the above-described embodiment, accurate determination of the compensation starting point and timing is achieved by acquiring stress and strain distribution data on the workpiece surface. By identifying the maximum stress in the turning section, the spatial distribution characteristics of the material deformation are grasped, and the location of the compensation starting point is determined accordingly. The greater the stress, the longer the compensation starting distance, ensuring that compensation is initiated promptly before the stress concentration area. The compensation timing can be dynamically adjusted based on the actual material deformation. In particular, in welding with multiple turning sections, controlling the compensation start time improves the uniformity of weld quality during friction stir welding on complex curved paths.

[0024] In conjunction with some embodiments of the first aspect, in some embodiments, after controlling the posture of the welding tool according to the real-time correction compensation tilt angle, the method further includes:

[0025] When the motion trajectory includes a docking interface, the docking position of the docking interface is obtained, and a transition area with a preset transition length is divided on both sides of the docking position; when there is a material height difference at the docking interface, in the transition area, a transition additional angle is added on the basis of the real-time correction compensation inclination angle; temperature data on both sides of the docking interface are obtained to obtain a docking temperature difference; when the docking temperature difference exceeds a preset docking temperature difference threshold, the rotation speed of the welding tool is adjusted according to the temperature adjustment amplitude.

[0026] In the above-described embodiment, by identifying the characteristics of the butt joint interface and implementing a corresponding transition adjustment strategy, the transition region is divided and an additional transition angle is added to smooth the transition caused by material height differences. Simultaneously, by monitoring the temperature difference across the butt joint interface and dynamically adjusting the rotational speed, the heat input distribution is balanced. This transition control mechanism, which comprehensively considers geometric characteristics and thermal state, can address discontinuities at the butt joint interface. This is particularly true when the butt joint interface is included in a complex curved trajectory. By precisely controlling the tool posture and heat input, the uniformity of the weld quality during friction stir welding on complex curved trajectories is improved.

[0027] In a second aspect, an embodiment of the present application provides an online friction stir welding testing system, which includes: one or more processors and a memory; the memory is coupled to the one or more processors, and the memory is used to store computer program code, the computer program code includes computer instructions, and the one or more processors call the computer instructions to enable the online friction stir welding testing system to execute the method described in the first aspect and any possible implementation method of the first aspect.

[0028] In a third aspect, an embodiment of the present application provides a computer program product comprising instructions. When the computer program product is run on a stir friction welding online testing system, the stir friction welding online testing system executes the method described in the first aspect and any possible implementation method of the first aspect.

[0029] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium comprising instructions. When the instructions are executed on a friction stir welding online testing system, the friction stir welding online testing system executes the method described in the first aspect and any possible implementation of the first aspect.

[0030] It is understood that the friction stir welding online testing system provided in the second aspect, the computer program product provided in the third aspect, and the computer storage medium provided in the fourth aspect are all used to execute the friction stir welding online testing method provided in the embodiments of this application. Therefore, the beneficial effects achievable by these methods can be referenced to the beneficial effects of the corresponding methods and will not be further elaborated here.

[0031] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0032] 1. This application addresses the unevenness of the inner and outer surfaces of curved trajectory welding due to differing path lengths by identifying turning segments in the motion trajectory and dynamically adjusting the welding tool's posture. First, the turning segments are identified by the curvature change rate, and the difference in path length between the inner and outer surfaces is calculated based on the turning angle and tool diameter. This geometric analysis ensures accurate understanding of the characteristics of the turning segments. Then, by calculating the action difference coefficient, the degree of uneven force on the inner and outer materials is quantified. Based on this, a compensation angle is determined, tilting the welding tool at a certain angle to increase the extrusion pressure and heat input in the outer area, thereby balancing the material flow inside and outside. More importantly, the mutual influence between multiple turning segments is taken into account, and the remaining compensation amount of the preceding turning segment is calculated using a decaying exponential function. Different superposition strategies are adopted based on the similarities and differences in the turning directions. When adjacent turning segments are in the same direction, the real-time compensation angle is increased to enhance the compensation effect; when the turning directions are opposite, the compensation angle is reduced to avoid overcompensation. This dynamic compensation mechanism, which takes into account the effects of heat accumulation and stress superposition, can accurately cope with various working conditions in complex curved trajectories, especially in the case of multiple consecutive turning sections. By controlling the posture of the welding tool, the uniformity of the weld quality during stir friction welding in complex curved trajectories is improved.

[0033] 2. This application identifies gap regions by real-time monitoring of the changing characteristics of axial force and torque, and considers the impact of gaps on the transmission of the compensation effect in the compensation calculation. By setting the attenuation coefficient of the attenuation exponential function to its maximum value in the gap region, the rapid attenuation of the compensation effect in the gap is simulated. This compensation transmission mechanism that considers the influence of gaps can effectively address situations where the compensation effect of the preceding steering section is blocked by gaps, avoiding the unreasonable continuation of the compensation effect after the gap, and improving the uniformity of weld quality during friction stir welding on complex curved trajectories.

[0034] 3. This application adopts differentiated treatment strategies based on void size. For small voids, lateral disturbance is used to increase material flow and mixing; for medium voids, increasing the rotational speed increases heat input and plasticization; and for large voids, a return repair method is used to eliminate defects. This gap-size-based hierarchical treatment mechanism selects the optimal treatment solution for voids with different characteristics, avoiding overtreatment of small defects while ensuring that large defects are fully repaired, thereby improving the uniformity of weld quality during friction stir welding on complex curved trajectories. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of an online friction stir welding testing method according to an embodiment of the present application;

[0036] Figure 2 This is another flow chart of the friction stir welding online testing method in the embodiment of the present application;

[0037] Figure 3 This is a schematic diagram of an exemplary hardware structure of a friction stir welding online testing system in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The terms used in the following examples of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. As used in the specification and appended claims of the present application, the singular expressions "a," "an," "said," "above," "the," and "this" are intended to include plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in the present application refers to and encompasses any or all possible combinations of one or more of the listed items.

[0039] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0040] In related technologies, the friction stir welding process is typically controlled using fixed tool postures and welding parameters. However, when a turning section appears in the welding trajectory, due to the different lengths of the inner and outer paths, the outer material needs to fill a larger space, while the heat input and extrusion pressure obtained are the same as those on the inner side, resulting in defects such as lack of fusion in the outer area. More seriously, when multiple turning sections are adjacent, the heat accumulation and plastic deformation generated by the previous turning section will affect the material flow state of the subsequent turning sections. This superposition effect of heat and stress makes it difficult for the fixed parameter control method to adapt to dynamically changing working conditions, resulting in uneven weld quality.

[0041] In an embodiment of the present application, a dynamic compensation method based on the characteristics of the turning section is proposed. The turning section is identified by calculating the rate of change of the trajectory curvature, and the difference in the inner and outer path lengths is calculated by combining the tool diameter and the turning angle. The action difference coefficient is introduced to quantify the degree of uneven force on the material, and the compensation inclination angle is determined accordingly to adjust the tool posture. In particular, considering the mutual influence of multiple turning sections, a decaying exponential function is used to calculate the remaining compensation amount of the preceding turning section, and different superposition strategies are adopted according to the similarities and differences in the turning directions. This realizes the control of heat accumulation and stress superposition effects, and improves the uniformity of weld quality.

[0042] Figure 1 The present invention is a flow chart of an online friction stir welding testing method according to an embodiment of the present invention, comprising the following steps:

[0043] S101. Obtain a motion trajectory of a welding tool, calculate a curvature change rate of each point on the motion trajectory, mark a trajectory segment consisting of adjacent points whose curvature change rate exceeds a preset curvature threshold as a turning segment, and calculate a turning angle of each turning segment.

[0044] Specifically, the welding path data from an engineering CAD drawing or 3D model is first imported to obtain a complete sequence of preset motion trajectory coordinates. This trajectory is discretized into a sufficiently dense set of path points, and the tangent vector is calculated for each path point. Based on the tangent vectors of adjacent path points, the curvature value of that point, i.e., the rate of change of the tangent vector, is calculated. The rate of change of the curvature along the path is further calculated. When the curvature rate of change exceeds a preset threshold, the area is marked as the starting point of the turning segment. The turning angle is then calculated by calculating the angle between the tangent vectors at the starting and ending points of the turning segment.

[0045] S102. For each turning section, calculate the path length difference between the inner and outer sides of the turning according to the welding tool diameter and the turning angle, and the effect difference coefficient reflecting the uneven force on the inner and outer materials; determine the compensation start time according to the position of the turning section; and calculate the compensation inclination angle according to the turning angle and the effect difference coefficient.

[0046] Specifically, when welding turns, due to the different path lengths on the outside and inside of the tool, the outer material needs to flow a longer distance, while the inner material flows a shorter distance. This path difference will cause uneven material flow, the outer material will have a stretching effect, and the inner material will accumulate. By adjusting the inclination angle of the welding tool, the force direction and pressure distribution of the tool angle on the material can be changed. When the tool tilts toward the outside, it will apply greater pressure to the outside, promote the flow of the outer material, and reduce the extrusion effect on the inner material, thereby balancing the flow state of the inner and outer materials and achieving a more uniform material distribution.

[0047] The path length difference is calculated using a geometric method: taking the center line of the welding tool as the reference, when the tool diameter and steering angle are known, the outer path length = (steering radius + tool diameter / 2) × steering angle, the inner path length = (steering radius - tool diameter / 2) × steering angle, and the path length difference = outer path length - inner path length.

[0048] The basic calculation formula for the action difference coefficient is: action difference coefficient = a × path length difference, where a is a pre-set proportional coefficient, an empirical coefficient obtained through statistical analysis of a large amount of welding test data. Its value reflects the degree of influence of the path length difference on the material flow unevenness. This coefficient needs to take into account the geometric characteristics of the welding tool (such as the ratio of the shoulder diameter to the needle diameter) and the welding process parameters (such as the matching relationship between the rotation speed and the feed rate). The optimal value range is determined through optimization tests. In practical applications, the influence of material properties on the coefficient must also be considered. It can be corrected to: action difference coefficient = a × path length difference × b, where b is the material property correction coefficient, a correction factor determined based on the physical property parameters of the material to be welded, such as plastic deformation characteristics, thermal conductivity, and yield strength. It is mainly used to adjust the actual mechanical response differences produced by different materials under the same geometric deformation conditions. Its value is obtained through standardized characterization of material properties and welding performance evaluation.

[0049] The calculation of the compensation angle requires comprehensive consideration of the steering angle and the action difference coefficient: Compensation angle = steering angle × action difference coefficient × c, where c is the compensation coefficient, an adjustment factor used to balance the theoretical calculated value with the actual compensation required. Its value is determined by analyzing the actual impact of the tool inclination angle on material flow during welding, combined with verification tests of weld formation quality at different steering angles. It is used to convert the degree of uneven material flow into a practical and executable compensation angle value. To ensure a smooth compensation transition, a sinusoidal function is often used in practical applications to gradually change the compensation angle: y(t) = y × sin(πt / T), where t is the compensation time, T is the total compensation time, and y is the compensation angle.

[0050] S103. When entering the real-time turning segment, obtain the preceding compensation inclination angle of the preceding turning segment and the remaining distance between the preceding turning segment and the real-time turning segment, and calculate the remaining compensation amount brought by the preceding turning segment using a decaying exponential function.

[0051] Specifically, when the welding tool enters a real-time turn segment, the impact of the preceding turn segment is first determined. A preceding turn segment is a turn segment that is adjacent to the current turn segment in both time and space. The difference between the compensation start time of the preceding turn segment and the compensation start time of the current real-time turn segment is calculated. If the compensation start time difference is less than a preset time threshold (determined by welding speed and process requirements), and the preceding turn segment is spatially adjacent to the current turn segment, it is considered a valid preceding turn segment.

[0052] After determining the preceding turning segment, its compensation inclination angle value is obtained as the initial quantity, and the actual distance (remaining distance) from the end point of the preceding turning segment to the current position is obtained. The actual distance from the end point of the preceding turning segment to the current position is obtained by obtaining the end point of the preceding turning segment and the starting point of the real-time turning segment through the known welding tool motion trajectory and turning segment position information. The path between these two points is integrated along the motion trajectory to obtain the actual path length. Specifically, the trajectory can be discretized into small line segments, and the accurate path distance is obtained by accumulating the lengths of these line segments. For complex curved trajectories, the influence of curvature needs to be considered to ensure the accuracy of the distance calculation. The remaining compensation amount is then calculated using a decaying exponential function. This function uses distance as the main decay basis, while considering the influence of tool diameter and turning angle on the decay rate. The exponential term of the function includes distance factors and geometric characteristic factors to ensure that the compensation amount decays smoothly with increasing distance.

[0053] The calculation of the remaining compensation amount can use the decay exponential function: In this decay exponential function, F0 represents the original compensation inclination of the previous turning segment, d represents the actual distance from the current position to the end point of the previous turning segment, L is the distance between the two turning segments, λ is the decay coefficient determined by the tool diameter and the turning angle, and n is the exponent used to adjust the decay smoothness. This double decay form is adopted because the exponential term Can provide the basic fast decay characteristics, and the polynomial term It provides a more delicate distance-sensitive adjustment. The combination of the two ensures that the compensation amount can be fully attenuated when it is far away from the previous turning section, and ensures a smooth transition when approaching the new turning section, avoiding sudden changes in the compensation amount, which is more in line with the actual physical characteristics of material flow.

[0054] S104: Determine whether the preceding turning segment and the real-time turning segment are turning in the same direction.

[0055] If yes, then execute the following step S105;

[0056] If not, return to execute the above step S106;

[0057] Specifically, determining the turn direction first requires obtaining the turning vectors for both turning segments. For each turning segment, the direction of rotation is determined by the cross product of its inlet and outlet tangent vectors: a positive cross product indicates a left turn; a negative cross product indicates a right turn. If the two turning segments have the same rotation direction, it's considered a same-direction turn; if they have different rotation directions, it's considered a different-direction turn.

[0058] Same-direction and counter-direction turns have different effects on material flow: With same-direction turns, the uneven material flow caused by the first turn has not yet been completely eliminated before the second turn in the same direction occurs. This further exacerbates the degree of material compression on the inside and the degree of material stretching on the outside, leading to a compounding of material flow unevenness. With counter-direction turns, the second turn forces the material to flow in the opposite direction. Here, areas squeezed in the first turn are stretched in the second, while areas previously stretched are squeezed. This opposing effect partially offsets the uneven material flow.

[0059] S105 , increasing the real-time compensation inclination angle of the real-time steering section by the remaining compensation amount to obtain a real-time corrected compensation inclination angle.

[0060] Specifically, in the case of unidirectional turns, the compensation inclination angle originally calculated for the current turn segment is added to the remaining compensation amount generated by the preceding turn segment. This superposition reflects the material flow characteristics: when two turns are unidirectional, the material flow unevenness caused by the previous turn (material accumulation on the inside and material stretching on the outside) will be superimposed on the material flow trend of the subsequent turn, resulting in even more uneven material distribution. Therefore, increasing the compensation inclination angle is necessary to provide stronger compensation to balance the exacerbated material flow unevenness.

[0061] During the first turning process, the inner material is compressed and accumulated, and the outer material is stretched. When entering the second same-direction turning process, the accumulated inner material will be further compressed, and the already stretched outer material will continue to be stretched. This superposition effect will cause the material distribution to be more uneven, increasing the risk of welding defects.

[0062] S106: Reduce the real-time compensation tilt angle by the remaining compensation amount to obtain a real-time corrected compensation tilt angle.

[0063] Specifically, in the case of counter-directional turns, the compensation angle originally calculated for the current turn segment is subtracted from the residual compensation generated by the preceding turn segment. This reduced compensation is based on the natural neutralization effect of material flow: when two turns are in counter-directional directions, the material flow unevenness caused by the previous turn (such as inward accumulation and outward stretching caused by a left turn) is naturally alleviated by the subsequent turn in the opposite direction, because the areas that were originally accumulated become outward and stretched, while the areas that were originally stretched become inward and compressed.

[0064] The material area that is compressed in the first turn will be transformed into an area that needs to be stretched in the second turn, and the material area that is stretched in the first turn will be transformed into an area that needs to be compressed in the second turn. This natural physical neutralization effect reduces the unevenness of material flow, so a smaller compensation inclination angle is required.

[0065] In some embodiments, in order to further improve the stability of welding quality, the surface profile of the workpiece and the vibration state during welding can be monitored in real time to dynamically adjust the compensation inclination angle and achieve vibration suppression, thereby ensuring the stability of the welding process and the quality of the weld.

[0066] First, a vision sensor acquires the workpiece surface profile data within a predefined area in front of and below the weld point. Based on this 3D profile data, the displacement deviation of the weld point in the workpiece normal direction (i.e., the difference between the expected and actual surface heights) and the actual normal vector of the workpiece surface at the contact point are calculated. These parameters reflect the actual geometric characteristics and deformation state of the workpiece surface.

[0067] Based on the calculated displacement deviation and the actual normal vector, a secondary correction is made to the real-time compensation tilt angle. This correction takes into account the influence of the actual surface condition of the workpiece on the welding process, enabling more precise control of the welding tool posture and ensuring ideal contact between the tool and the workpiece.

[0068] Simultaneously, vibration signals from the welding process are acquired in real time and spectrally analyzed. By analyzing the frequency characteristics and amplitude variations of the vibration signals, potential instability factors are promptly identified. Based on the vibration signal analysis results, the required vibration suppression reaction force is calculated and applied through an active damping device, thereby proactively suppressing harmful vibrations during the welding process.

[0069] When the amplitude of the detected vibration signal exceeds a preset threshold for destabilizing vibration, a two-stage response is implemented: first, the spindle speed of the welding tool is reduced, and then, based on the frequency characteristics of the vibration signal, the vibration suppression reaction force is increased. This combined measure effectively suppresses most destabilizing vibrations. If the vibration still exceeds the threshold after the spindle speed is reduced, an abnormal vibration alarm signal is generated, prompting the operator to intervene.

[0070] This dynamic monitoring and adjustment process can address various unstable factors during welding. Real-time monitoring of the workpiece surface profile ensures accurate control of the welding tool's posture, while vibration monitoring and suppression mechanisms provide reliable stability for the welding process. By sensing the workpiece surface condition and process vibration characteristics, real-time optimization and adjustment of welding parameters are achieved. This active sensing and dynamic response mechanism can promptly detect and resolve potential problems, avoiding the occurrence of welding defects, while also providing reliable process monitoring and early warning capabilities. This is particularly true when welding complex curved trajectories. By controlling the tool's posture and suppressing harmful vibrations, the uniformity and consistency of weld quality during friction stir welding are improved.

[0071] S107 , controlling the posture of the welding tool according to the real-time correction compensation tilt angle.

[0072] Specifically, the welding tool's posture is adjusted in real time based on the calculated real-time correction compensation tilt angle. During this process, the compensation tilt angle is converted into an angular parameter in the tool coordinate system, and an interpolation operation is used to ensure smooth changes in the tool's posture.

[0073] In some embodiments, when the welding trajectory includes a butt joint interface, the material flow and heat input at the butt joint interface can be controlled by identifying the butt joint position, dividing the transition area, and dynamically adjusting the tool posture and process parameters, thereby ensuring the quality stability of the butt weld.

[0074] First, the specific position information of the docking interface is obtained, and a transition area of ​​preset length is divided on both sides of the docking position. The setting of the transition area provides space for the smooth transition of process parameters, avoiding welding defects that may be caused by sudden changes in parameters.

[0075] When there's a height difference between the materials at the interface, the real-time compensation angle is further adjusted within the transition zone, tilting the tool toward the higher side. This increases the transition angle, which is positively correlated with the material height difference. This tilt adjustment increases the tool's squeezing effect on the higher material, promoting downward flow, while reducing squeezing on the lower material, helping to achieve uniform material flow and mixing within the height transition zone.

[0076] Simultaneously, a temperature sensor acquires real-time temperature data on both sides of the butt joint interface and calculates the temperature difference. If the temperature in the area approaching the butt joint is higher, the welding tool's rotational speed is reduced to minimize heat input. If the temperature in the area approaching the butt joint is lower, the rotational speed is increased to provide more heat input. The speed adjustment is proportional to the temperature difference; the greater the temperature difference, the greater the adjustment. This predictive speed control ensures uniform heat input at the butt joint interface, maintaining a consistent degree of plasticization.

[0077] This dynamic parameter control strategy at the interface achieves precise control of tool posture and heat input. This multi-parameter collaborative control method, combining material height and temperature differences, addresses the issues of uneven material flow and unbalanced heat input at the interface during friction stir welding under complex curved trajectories, improving the uniformity and consistency of weld quality.

[0078] In the above-described embodiment, by identifying turning segments in the motion trajectory and dynamically adjusting the welding tool's posture, the problem of uneven flow between the inner and outer sides of curved trajectory welding caused by different path lengths is addressed. First, turning segments are identified by the curvature change rate, and the difference in path length between the inner and outer sides is calculated based on the turning angle and tool diameter. This geometric analysis ensures accurate understanding of the characteristics of the turning segments. By calculating the action difference coefficient, the degree of uneven force applied to the inner and outer materials is quantified. Based on this, a compensation angle is determined, tilting the welding tool at a certain angle to increase the extrusion pressure and heat input in the outer region, thereby balancing the material flow inside and outside. More importantly, the interaction between multiple turning segments is taken into account, and the residual compensation amount of the preceding turning segment is calculated using a decaying exponential function. Different overlay strategies are then applied based on the similarities and differences in the turning directions. When adjacent turning segments are in the same direction, the real-time compensation angle is increased to enhance the compensation effect; when the turning directions are opposite, the compensation angle is reduced to avoid overcompensation. This dynamic compensation mechanism, which takes into account the effects of heat accumulation and stress superposition, can accurately cope with various working conditions in complex curved trajectories, especially in the case of multiple consecutive turning sections. By controlling the posture of the welding tool, the uniformity of the weld quality during stir friction welding in complex curved trajectories is improved.

[0079] In other embodiments of the present application, the presence of a gap during welding may block the transfer of the compensation effect of the preceding turning section, causing the compensation effect to continue beyond the gap and resulting in overcompensation. The online friction stir welding testing method provided in this application can identify the location of the gap, increase the attenuation coefficient in the gap area, and control the transfer characteristics of the compensation effect.

[0080] like Figure 2 FIG. 1 is another flow chart of the friction stir welding online testing method provided in an embodiment of the present application, comprising the following steps:

[0081] S201. Obtain a motion trajectory of a welding tool, calculate a curvature change rate of each point on the motion trajectory, mark a trajectory segment consisting of adjacent points whose curvature change rate exceeds a preset curvature threshold as a turning segment, and calculate a turning angle of each turning segment.

[0082] S202. For each turning section, calculate the path length difference between the inner and outer sides of the turning according to the welding tool diameter and the turning angle and the action difference coefficient reflecting the uneven force of the inner and outer materials, and calculate the compensation inclination angle according to the turning angle and the action difference coefficient.

[0083] S203 , acquiring stress and strain distribution data on the workpiece surface and identifying the maximum stress value of each turning section.

[0084] Specifically, workpiece surface stress and strain distribution data is acquired primarily through two methods: pre-analysis and real-time monitoring. During the pre-analysis phase, stress and strain simulation is performed on the entire welding trajectory. Based on the workpiece material properties, welding parameters, and trajectory geometry, the stress distribution likely to occur during welding is calculated. This simulation can predict potential stress concentration areas in each turning section during welding.

[0085] During the real-time monitoring phase, a network of stress and strain sensors deployed on the workpiece surface collects real-time stress and strain data during the welding process. These sensors, typically in the form of fiber Bragg gratings or resistance strain gauges, continuously monitor stress changes on the workpiece surface. This collected data is then compared and integrated with pre-analysis results to obtain more accurate stress distribution information.

[0086] To identify the maximum stress in the turning section, the entire welding track is first divided into several turning sections based on its geometric characteristics. Then, within each turning section, the stress data in that area is analyzed using a data processing algorithm to identify the local maximum.

[0087] S204: Determine the compensation starting point of the turning section according to the maximum stress value of the turning section.

[0088] Specifically, the compensation starting point is determined based on the maximum stress in the turning section. A higher maximum stress indicates greater material deformation in that area, necessitating earlier compensation to ensure adequate stress release and material flow regulation. Consequently, a positive correlation between maximum stress and compensation starting distance is established: the greater the maximum stress, the earlier the compensation starting point, meaning the greater the distance from the turning section's curve apex.

[0089] First, set the baseline stress value and baseline distance parameters. The baseline stress value is typically selected as a certain percentage of the material's yield strength, while the baseline distance is determined based on process experience. Then, the actual compensation starting distance is determined using the following relationship: when the maximum measured stress is equal to the baseline stress value, the baseline distance is used. When the maximum stress value exceeds the baseline stress value, the compensation starting distance is proportionally increased. When the maximum stress value is less than the baseline stress value, the compensation starting distance is proportionally decreased.

[0090] S205: Obtain the compensation start time of the corresponding turning section according to the compensation start point.

[0091] Specifically, the compensation start time is determined by calculating the time required for the welding tool to reach the compensation starting point from its starting position. This calculation is primarily based on the welding speed and path characteristics, and needs to account for speed variations and path characteristics during the actual welding process. In the most basic case, when the welding speed remains constant, the required time can be simply calculated by dividing the distance by the speed. However, in actual applications, the welding process often involves acceleration and deceleration stages, and the welding speed may need to be reduced when approaching a turning point. Therefore, more complex time calculations using kinematic formulas are required.

[0092] In some embodiments, the welding trajectory typically includes multiple turning segments, with the distance between adjacent turning segments being relatively short. In such situations, the welding tool must frequently adjust its acceleration and deceleration. Traditional compensation time calculation methods based on constant speed struggle to accurately predict when the tool will reach the compensation starting point, which can easily lead to inconsistent compensation timing and unstable weld quality.

[0093] To address these issues, a dynamic time prediction method based on integration is employed. The welding tool's velocity profile is acquired in real time. By performing a segmented integral calculation on the velocity-time curve, the actual distance the tool travels during acceleration and deceleration is determined. Simultaneously, the tool's real-time position and velocity are continuously monitored, and the estimated time to reach the compensation starting point is dynamically updated. The compensation start sequence is adjusted based on this updated time to ensure precise implementation of the compensation action.

[0094] By adopting this dynamic time prediction and compensation timing adjustment mechanism, the problem of compensation timing control under variable speed welding conditions is solved. It not only improves the timing accuracy of the compensation action, but also ensures the smooth transition of the compensation process between adjacent turning sections, and improves the consistency of weld quality during the welding process of complex components.

[0095] S206 : When a point is detected where the axial force and torque in the remaining path decrease simultaneously and the decreasing rates both exceed corresponding decreasing rate thresholds, it is marked as a starting point of the gap area.

[0096] Specifically, the axial force and torque changes during the welding process are monitored in real time. Under normal welding conditions, the axial force and torque fluctuate within a relatively stable range. When the welding tool encounters a gap area, the sudden decrease in material support causes a significant decrease in both the axial force and torque. The real-time rate of change of these two parameters is calculated and compared with a preset rate of decrease threshold. When the rate of decrease of the axial force and torque exceeds their respective thresholds, the location is marked as the starting point of the gap area.

[0097] Due to the lack of material support in the gap area, the compensation effect of the previous turning section cannot be effectively transferred to the subsequent area, blocking the remaining compensation amount of the previous bend from being transferred backward, resulting in a sudden change in the compensation effect. Therefore, it is necessary to consider the impact of the gap during the compensation process and adjust the compensation strategy in time to ensure the continuity and uniformity of the weld quality.

[0098] S207 . After the start point of the gap region appears, when a point where the axial force and torque increase simultaneously is detected, it is marked as the end point of the gap region.

[0099] Specifically, after marking the starting point of the gap area, the axial force and torque changes during the welding process are continuously monitored. When the welding tool passes through the gap area and re-enters the solid material area, the axial force and torque will simultaneously show an upward trend due to the recovery of the material support force. The changing characteristics of these two parameters are analyzed in real time. When they are detected to show a simultaneous upward trend, the location is marked as the end point of the gap area. This detection method not only considers the instantaneous changes in parameters but also incorporates the overall characteristics of the gap area, ensuring the reliability of the detection results.

[0100] In some embodiments, differentiated processing strategies are adopted according to the length of the gap area, including lateral disturbance, speed increase and repair welding, so as to achieve precise processing of gaps of different sizes and improve welding quality.

[0101] When the gap length is less than the minimum value in the threshold range, lateral perturbation is used. First, the gap area length is calculated, that is, the straight-line distance from the starting point to the end point of the gap, and then the required perturbation amplitude is calculated based on this distance. The perturbation amplitude is proportional to the gap length. This correspondence ensures that the perturbation amount matches the gap size. Larger gaps correspond to larger perturbation amplitudes, which can bring more material replenishment; smaller gaps correspond to smaller perturbation amplitudes to avoid excessive stirring. The welding tool is controlled to perform a lateral perturbation action. This instantaneous lateral movement increases material flow, promotes material filling and mixing in the gap, and eliminates small gap defects.

[0102] When the gap length is within the threshold, the speed is increased. The required speed increase is first calculated based on the gap length, with the speed increase proportional to the gap length. This proportional relationship ensures that the increase in heat input is appropriate to the gap size, avoiding excessive or insufficient heat input. Larger gaps correspond to higher speed increases, providing more heat input and stirring; smaller gaps correspond to lower speed increases, preventing excessive heat input. Increasing the speed increases the plasticization and fluidity of the material, while the enhanced stirring action promotes thorough mixing of the material, improving the filling of medium-sized gaps.

[0103] When the gap length exceeds the maximum value within the threshold range, the repair welding process is initiated. The detailed location information of the current gap area, including the coordinates of the starting and ending points, is recorded. A defect warning signal is then issued to alert the operator. The welding tool is then controlled to return to the starting position of the gap area for repair welding. After the repair weld is complete, the welding tool resumes its original trajectory. This process ensures that large gaps are completely repaired, avoiding serious weld defects.

[0104] This differentiated approach based on void size allows for precise control of void defects. Lateral perturbations promote material replenishment in small voids, while increased rotational speed enhances material flow in medium-sized voids. Repair welding completely resolves the problem of large voids. This multi-layered approach improves weld uniformity during friction stir welding on complex curved paths.

[0105] S208 , calculating the remaining compensation amount caused by the preceding turning segment by using an attenuation exponential function, and setting the attenuation coefficient of the attenuation exponential function to a preset maximum attenuation coefficient in the gap area.

[0106] Specifically, during the welding process, the compensation effect of the preceding turning section gradually decays with increasing distance. This attenuation characteristic is described by a decay exponential function. The transfer effect of the compensation amount is controlled by adjusting the attenuation coefficient. Furthermore, a regional calculation strategy is employed. Based on the gap detection results, the welding path is divided into a normal area and a gap area. Different attenuation coefficients are applied to these two areas, enabling differentiated control of the compensation amount in different areas.

[0107] When a gap region is detected (i.e., the area from the start to the end of the gap region), the transmission of the compensation effect is significantly affected due to the lack of material support. The attenuation coefficient of the attenuation exponential function is set to a preset maximum value to reflect the rapid decay of the compensation effect in the gap. In normal areas, the standard attenuation coefficient is used to calculate the remaining compensation amount. This calculation takes into account the natural decay of the compensation effect with distance, allowing the compensation amount to gradually decrease with increasing distance from the turning section, ensuring smooth transmission of the compensation effect.

[0108] S209: Determine whether the preceding turning segment and the current turning segment are turning in the same direction;

[0109] If yes, then execute the following step S210;

[0110] If not, return to execute the above step S211;

[0111] S210: Reduce the real-time compensation inclination angle of the real-time steering section by the remaining compensation amount to obtain a real-time corrected compensation inclination angle.

[0112] S211 , increasing the real-time compensation tilt angle by the remaining compensation amount to obtain a real-time corrected compensation tilt angle.

[0113] S212: Control the posture of the welding tool according to the real-time correction compensation tilt angle.

[0114] Steps S201-S202, S209-S212 and Figure 1 In the illustrated embodiment, steps S101 - S102 and S104 - S107 are similar, and reference may be made to the descriptions in the steps, which will not be repeated here.

[0115] In the above embodiment, the identification of the gap and the dynamic adjustment of the compensation effect are achieved by real-time monitoring of the changing characteristics of the axial force and torque. The starting position of the gap is identified by simultaneously analyzing the rate of decrease of the force and torque, and the end position of the gap is determined by using the parameter recovery characteristics, thereby defining the range of the gap area. In particular, it is recognized that the gap will significantly affect the transmission of the compensation effect. By setting the attenuation coefficient of the attenuation exponential function to the maximum value in the gap area, the rapid attenuation characteristics of the compensation effect at the gap are simulated. This compensation transmission mechanism that takes the influence of the gap into consideration can effectively deal with the situation where the compensation effect of the preceding steering section is blocked by the gap, and avoids the unreasonable continuation of the compensation effect after the gap. By controlling the transmission characteristics of the compensation effect, the uniformity of the weld quality during stir friction welding under complex curve trajectories is improved.

[0116] The following introduces an exemplary friction stir welding online testing system 300 provided in an embodiment of the present application. Figure 3 Schematic diagram of an exemplary hardware structure of a friction stir welding online testing system 300 provided in an embodiment of the present application.

[0117] In some embodiments, the friction stir welding online testing system 300 is a computer device or the friction stir welding online testing system 300 includes a computer device. The computer device includes a processor, a memory, and a network interface connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data. The network interface of the computer device is used to communicate with other external terminals or servers via a network connection. In some embodiments, the network interface can be a wired network interface, and in some embodiments, the network interface can also be a wireless network interface. When the computer program is executed by the processor, the method in the embodiment of the present application is implemented.

[0118] Those skilled in the art will understand that Figure 3The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0119] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0120] As used in the above embodiments, the term “when…” may be interpreted as “if…” or “after…” or “in response to determining…” or “in response to detecting…”, depending on the context. Similarly, the phrases “upon determining…” or “if (stated condition or event) is detected” may be interpreted as “if determining…” or “in response to determining…” or “upon detecting (stated condition or event)” or “in response to detecting (stated condition or event)”, depending on the context.

[0121] In the above embodiments, all or part of the embodiments can be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disk, hard disk, tape), optical media (e.g., DVD), or semiconductor media (e.g., solid-state drive).

[0122] Those skilled in the art will appreciate that all or part of the process steps in the above-described method embodiments can be implemented by a computer program instructing the relevant hardware. The program can be stored in a computer-readable storage medium, and when executed, the program can include the process steps in the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A friction stir welding online testing method, characterized in that: include: Obtaining a motion trajectory of the welding tool, calculating a curvature change rate of each point on the motion trajectory, marking a trajectory segment consisting of adjacent points whose curvature change rate exceeds a preset curvature threshold as a turning segment, and calculating a turning angle of each turning segment; For each steering section, the difference in path length between the inner and outer sides of the steering section and an action difference coefficient reflecting the uneven force applied to the inner and outer materials are calculated based on the diameter of the welding tool and the steering angle. The compensation start time is determined based on the position of the steering section. The compensation inclination angle is obtained by multiplying the steering angle, the action difference coefficient, and a preset compensation coefficient. The action difference coefficient is proportional to the path length difference. The preset compensation coefficient is an adjustment factor used to balance a theoretically calculated value with the actual required compensation amount. When entering the real-time turning section, the preceding compensation inclination angle of the preceding turning section and the remaining distance between the preceding turning section and the real-time turning section are obtained, the remaining compensation amount brought by the preceding turning section is calculated by using the decay exponential function, and it is determined whether the preceding turning section and the real-time turning section are turning in the same direction; the preceding turning section is the previous turning section adjacent to the real-time turning section and the time difference between the compensation start time and the real-time turning section is less than the preset remaining time threshold; the decay exponential function is , where F0 is the original compensation inclination angle of the preceding steering segment, d is the distance from the current position to the end point of the preceding steering segment, L is the distance between the two steering segments, λ is the attenuation coefficient determined by the tool diameter and the steering angle, and n is an exponent used to adjust the attenuation smoothness; If so, the real-time compensation inclination angle of the real-time steering section is increased by the residual compensation amount to obtain a real-time corrected compensation inclination angle; If not, reducing the real-time compensation tilt angle by the residual compensation amount to obtain a real-time corrected compensation tilt angle; The posture of the welding tool is controlled according to the real-time corrected compensation tilt angle.

2. The method according to claim 1, characterized in that When entering the real-time turning section, obtaining the preceding compensation inclination angle of the preceding turning section and the remaining distance between the preceding turning section and the real-time turning section, and calculating the remaining compensation amount brought by the preceding turning section by using a decaying exponential function, specifically includes: When a point is detected where the axial force and torque in the remaining path decrease simultaneously and the decrease rate exceeds the corresponding decrease rate threshold, it is marked as the starting point of the gap area; the remaining path is the path between the previous turning segment and the real-time turning segment; After the start point of the gap region appears, when the point where the axial force and the torque simultaneously increase is detected, it is marked as the end point of the gap region; The remaining compensation amount brought by the preceding turning section is calculated by using an attenuation exponential function, and the attenuation coefficient of the attenuation exponential function is set to a preset attenuation coefficient maximum value in the gap area; the gap area is the area from the starting point of the gap area to the end point of the gap area.

3. The method according to claim 2, characterized in that After detecting that the axial force and the torque increase simultaneously and marking it as the end point of the gap region, the method further includes: When the gap region length is less than the minimum value in a preset gap region threshold range, a disturbance amplitude is calculated based on the gap region length, and the welding tool is controlled to perform a lateral disturbance according to the disturbance amplitude; the gap region length is the straight-line distance from the starting point of the gap region to the ending point of the gap region; and the disturbance amplitude is proportional to the gap region length; When the length of the gap region is within the gap region threshold range or equal to the boundary value of the gap region threshold range, a speed boost value is calculated according to the gap region length, and the welding tool is controlled to increase the speed by the speed boost value; the speed boost value is proportional to the gap region length; When the length of the gap area is greater than the maximum value in the preset gap area threshold range, the position information of the gap area is recorded, a defect warning signal is issued, and the welding tool is controlled to return to the starting point of the gap area for repair welding and then move forward again along the motion trajectory.

4. The method according to claim 1, wherein Before controlling the posture of the welding tool according to the real-time correction and compensation tilt angle, the method further includes: Acquire three-dimensional contour data of the workpiece surface within the preset welding spot monitoring area in front of and below the welding spot; Calculating a displacement deviation of the welding point in the normal direction of the workpiece and an actual normal vector of the workpiece surface at the contact point based on the three-dimensional profile data; the displacement deviation is the difference between the expected surface height and the actual surface height of the workpiece; The real-time corrected compensation tilt angle is corrected twice according to the displacement deviation and the actual normal vector.

5. The method according to claim 4, characterized in that After performing secondary correction on the real-time correction compensation tilt angle according to the displacement deviation and the actual normal vector, the method further includes: Acquiring a vibration signal during the welding process, and performing spectrum analysis on the vibration signal; Calculating a vibration suppression reaction force according to the vibration signal and controlling an active damping device to apply the vibration suppression reaction force; When it is detected that the amplitude of the vibration signal exceeds a preset destabilizing vibration threshold, reducing the spindle speed of the welding tool and increasing the vibration suppression reaction force according to the frequency of the vibration signal; When the amplitude of the vibration signal still exceeds the unstable vibration threshold after the spindle speed is reduced, an abnormal vibration alarm signal is generated.

6. The method according to claim 1, characterized in that The step of determining the compensation start time according to the position of the turning section specifically includes: Acquiring stress and strain distribution data on the workpiece surface and identifying the maximum stress value of each turning section; Determining a compensation starting point of the turning section according to the maximum stress value of the turning section; the maximum stress value of the turning section is proportional to the distance between the compensation starting point and the corner vertex of the turning section; The compensation starting time corresponding to the turning section is obtained according to the compensation starting point.

7. The method according to claim 1, characterized in that After controlling the posture of the welding tool according to the real-time correction and compensation tilt angle, the method further includes: When the motion trajectory includes a docking interface, obtaining a docking position of the docking interface, and dividing a transition area of ​​a preset transition length on both sides of the docking position; In the case where there is a material height difference at the docking interface, in the transition region, a transition additional angle is added on the basis of the real-time correction compensation inclination angle; the transition additional angle is proportional to the material height difference; Acquiring temperature data on both sides of the docking interface to obtain a docking temperature difference; When the docking temperature difference exceeds a preset docking temperature difference threshold, the rotation speed of the welding tool is adjusted according to a temperature adjustment amplitude; the temperature adjustment amplitude is proportional to the docking temperature difference.

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

9. A computer program product comprising instructions, characterized in that When the computer program product is run on a friction stir welding online testing system, the friction stir welding online testing system is enabled to perform the method according to any one of claims 1 to 7.

10. A computer-readable storage medium comprising instructions, characterized in that: When the instruction is executed on a friction stir welding online testing system, the friction stir welding online testing system is enabled to perform the method according to any one of claims 1 to 7.

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