A collaborative control method integrating laser cutting and beveling of steel structures

Abstract

This invention belongs to the field of laser processing technology, specifically a collaborative control method for integrating laser cutting and beveling of steel structures. It determines the clamping points based on the processing path, heat-affected zone, and fixture accessibility, ensuring the clamping layout matches the cutting segment distribution and improving processing stability. After the current cutting segment is completed, the fixture moves along the feed direction to the starting position of the next segment to be processed. The distance between this starting position and the end of the completed segment is not less than the preset heat-affected zone width, preventing the fixture from entering the heat-affected zone and reducing the risk of reference drift. By acquiring three non-collinear feature points on the intersection contour of the surface to be fitted and the workpiece, the spatial trajectory of the beveling process is determined, ensuring the beveling path matches the actual surface posture and improving the assembly fit. Deformation and deflection are detected in real time; when the change exceeds a threshold, a trajectory and laser frequency compensation are generated to collaboratively correct geometric errors and thermal input. Continuous monitoring and re-correction form a closed-loop feedback control mechanism.

Description

Technical Field

[0001] This invention belongs to the field of laser processing technology, specifically a collaborative control method for integrating laser cutting and beveling of steel structures. Background Technology

[0002] As the application of steel structure components in bridges, prefabricated buildings, and large stadiums continues to expand, the demand for high-precision cutting and beveling of steel profiles, box-type components, and plate-beam connectors is increasing. To improve processing efficiency, current production scenarios typically aim to continuously complete straight cutting and beveling on the same processing platform to reduce the number of workpiece transfers and repeated clamping.

[0003] In existing technologies, laser cutting and beveling of steel structural components typically employ pre-programmed offline processes, fixed clamping, and multi-stage execution. Specifically, one approach first generates a cutting path based on a theoretical model, and then the processing equipment completes the cutting according to a preset program; another approach, after completing the straight cut, transfers the workpiece to another station for beveling.

[0004] However, the existing technology still has the following limitations: 1. In the continuous laser processing, uneven heating of the workpiece is prone to thermal deformation. The workpiece deflection will continue to change with the cutting process. However, the existing solutions mostly follow the initial path and lack a real-time correction mechanism for the deformation state during processing. This can easily cause the accumulation of positional deviations in subsequent cutting segments, which in turn affects the cutting accuracy and forming quality.

[0005] 2. The existing multi-point clamping does not fully consider the re-clamping connection problem after the cutting segment is completed. When the distance between the moving position of the clamp and the end of the completed cutting segment is not set reasonably, the subsequent processing area is likely to fall into the heat-affected zone, resulting in changes in local stress state, clamping reference drift or unstable re-clamping positioning, thereby reducing the processing consistency of the entire path.

[0006] 3. For beveling scenarios that require assembly with other components, existing technologies typically generate beveling trajectories based on theoretical cross-sections or single contour lines. They lack a trajectory construction method that incorporates the actual spatial posture of intersecting contours, resulting in deviations between the beveling trajectory and the actual mating surface, which in turn affects the subsequent assembly and fitting effect. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, this invention provides a collaborative control method for integrating laser cutting and beveling of steel structures, which can effectively solve the problems mentioned in the prior art.

[0008] The objective of this invention can be achieved through the following technical solution: a collaborative control method integrating laser cutting and beveling of steel structures, comprising: Based on the processing path, determine multiple clamping points on the workpiece to be processed, and use no less than two fixtures to implement multi-point clamping. Divide the processing path into multiple cutting segments and perform laser straight cutting segment by segment.

[0009] After the current cutting segment is completed, the fixture that is holding the current cutting segment will be moved along the feed direction to the starting position of the next segment to be processed. Taking the end position of the completed cutting segment in the workpiece coordinate system as the reference, the distance between the moving endpoint and the end of the completed cutting segment is not less than the preset heat-affected zone width under the current laser process parameters.

[0010] The workpiece is held at the end by a rotating fixture and driven to rotate around its own axis. The spatial coordinates of three non-collinear feature points on the intersecting contour of the surface to be fitted and the workpiece are obtained. Based on this, the spatial trajectory for beveling is determined and beveling is performed.

[0011] The deformation and deflection of the workpiece are acquired in real time throughout the laser straight cutting and bevel cutting process. If the change exceeds the preset threshold, a compensation amount is generated based on the change to correct the processing trajectory and laser pulse frequency of the subsequent unprocessed cutting segment.

[0012] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: (1) The present invention determines multiple clamping points based on the processing path, heat-affected zone and fixture accessibility, which enables the clamping layout to match the distribution of subsequent cutting segments, thereby improving the support stability of the workpiece during continuous processing while ensuring processing accessibility.

[0013] (2) By moving the clamping fixture along the feed direction to the starting position of the next segment to be processed after the current cutting segment is completed, and limiting the distance between the moving endpoint and the end of the completed cutting segment to be no less than the width of the preset heat-affected zone, the present invention can prevent the clamping fixture from re-entering the high heat-affected zone, thereby reducing the risk of clamping reference drift and ensuring the stability of re-clamping of subsequent cutting segments.

[0014] (3) By obtaining three non-collinear feature points on the intersecting contour of the surface to be fitted and the workpiece to be processed, and determining the beveling processing spatial trajectory based on the three feature points, the beveling processing path can be kept consistent with the spatial posture of the actual surface to be fitted, thereby improving the beveling processing accuracy and subsequent assembly fitting effect.

[0015] (4) This invention detects the deformation and deflection of the workpiece in real time, and generates trajectory compensation and laser pulse frequency compensation when the change exceeds a preset threshold. It can simultaneously correct geometric processing errors and thermal input status, and continuously perform deformation monitoring, compensation generation and correction in subsequent processing to form a closed-loop feedback control mechanism. Attached Figure Description

[0016] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0018] Figure 2 This is a flowchart of the present invention, which divides the processing path into multiple cutting segments and performs laser straight cutting segment by segment.

[0019] Figure 3 The present invention provides a logical flowchart for determining whether three feature points constitute a non-collinear distribution. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Reference Figure 1 As shown, the present invention provides a collaborative control method for integrating laser cutting and beveling of steel structures, including: S1 determining multiple clamping points on the workpiece to be processed according to the processing path, and using no less than two clamps to perform multi-point clamping, dividing the processing path into multiple cutting segments and performing laser straight cutting segment by segment.

[0022] Considering that the processing path of steel structural components and the layout of fixtures jointly affect the constraint stiffness and thermal deformation, if the clamping point deviates from the high stiffness zone, it is easy to cause vibration and accuracy loss. The processing path is divided into multiple cutting segments according to the connection relationship, and laser direct cutting and fixture movement and re-clamping are performed in sequence, so that effective constraints can be maintained at each processing stage.

[0023] Based on this, the process of determining multiple clamping points on the workpiece according to the machining path is as follows: Obtain the structural dimensions, machining path, and fixture travel information of the workpiece to be processed; among which, the structural dimensions include the length, width, thickness, end contour, and location of local reinforcement structures of the workpiece to be processed; the machining path includes the spatial path data corresponding to each laser straight cutting path segment and beveling area; the fixture travel information includes the lateral reachable range, longitudinal reachable range, and rotational capability range of each fixture.

[0024] Acquire CNC programming files, offline programming files, or machining path data issued by the upper control system, and uniformly convert the machining path data to the workpiece coordinate system to form a standard trajectory dataset that includes the spatial coordinates of each trajectory point, trajectory type identifier, machining attribute identifier, and trajectory execution sequence identifier.

[0025] The trajectory type identifier can be used to distinguish between straight trajectory, curved trajectory, or polyline trajectory; the machining attribute identifier can be used to distinguish between straight cutting trajectory and beveling trajectory; the workpiece coordinate system takes the length direction of the workpiece as the X-axis, its transverse direction as the Y-axis, its thickness direction as the Z-axis, and the machining start point or fixture reference point as the origin.

[0026] The trajectory points are sorted according to the trajectory execution order, and each independent path segment is identified based on the coordinate change relationship between adjacent trajectory points. Specifically, starting from the current trajectory point to be processed, the arithmetic mean of the distance between three consecutive points is calculated along the trajectory execution order and used as the reference step size for the corresponding local segment. When the distance between the next adjacent trajectory points is not greater than 1.5 times the reference step size and the corresponding processing attributes are consistent, the adjacent trajectory points can be merged into the same path segment.

[0027] When the distance between adjacent trajectory points is greater than 1.5 times the baseline step size, or when the corresponding processing attributes change, the corresponding position can be determined as the path segment boundary point, thereby completing the segmentation identification of the overall processing path.

[0028] It should be noted that taking 1.5 times the baseline step size as the dividing criterion is an empirical threshold selected to balance the allowable local fluctuations in the distribution of trajectory points with the accuracy of identifying macroscopic boundaries between path segments; for processing paths with different trajectory point densities, this multiple can be adjusted within the range of 1.2 to 2.0.

[0029] The first and last trajectory points of each path segment are extracted and recorded as the starting and ending coordinates of the path segment, respectively.

[0030] A direction vector is constructed based on the starting and ending coordinates of each path segment, and then normalized to obtain the extension direction of the path segment. If the corresponding path segment contains multiple intermediate trajectory points, the extension direction can be fitted and corrected by combining the distribution trend of each intermediate trajectory point.

[0031] Based on the extension directions of adjacent path segments, corresponding direction vectors are constructed, and the angle relationship is represented by the dot product of adjacent direction vectors. Simultaneously, the Euclidean distance between the ending coordinates of the previous path segment and the starting coordinates of the next path segment is taken as the trajectory transition distance. Specifically, let the direction vector of the previous path segment be... The direction vector of the next path segment is Let the ending coordinates of the previous path segment be... The starting coordinates of the next path segment are ,but and dot product Used to characterize the degree of continuity between two path segments in a direction. and Spatial distance between It is used to characterize the degree of connection between two path segments in terms of location.

[0032] like If the value is zero, then the two are considered to be directly connected; if... Greater than zero and If the dot product is greater than zero, then the two are considered to be in a jump connection relationship; if Greater than zero and If the dot product of the two is less than or equal to zero, then the two are considered to be intersecting and connected.

[0033] The starting coordinates, ending coordinates, extension direction, and connection relationships between adjacent path segments are associated and stored to form path analysis results used for segment division, clamping point determination, and subsequent processing sequence planning.

[0034] It should be noted that when the path segment is a straight line segment, the coordinates of the first and last points can be directly used as the starting and ending coordinates; when the path segment is a curved or polyline segment, the starting and ending trajectory coordinates of the path segment in the execution sequence are used as the corresponding starting and ending coordinates.

[0035] When the processing path data does not have separate entry and exit segments, the starting coordinates are directly determined as the entry position of the corresponding cutting segment, and the ending coordinates are determined as the exit position of the corresponding cutting segment.

[0036] When the processing path data includes an introductory segment and an outtroductory segment, the intersection position of the introductory segment and the target cutting contour is determined as the introductory position, and the separation position of the target cutting contour and the outtroductory segment is determined as the outtroductory position, thereby obtaining the actual starting and ending cutting boundaries of the corresponding cutting segment.

[0037] Based on the preset heat-affected zone width corresponding to the current laser process parameters, the specific heat-affected zone coverage areas on both sides of the corresponding cutting segment are determined as follows: Construct the center trajectory of the current cutting segment based on the entry and exit positions, and determine the tangential direction of the trajectory within the local cutting plane where the current cutting segment is located, according to the extension direction of the center trajectory, and then determine the normal directions on both sides perpendicular to the tangential direction.

[0038] Using each point on the central trajectory as a reference, the width of the preset heat-affected zone is offset along the normal direction on both sides to form the boundary lines on both sides of the cutting segment. The strip-shaped area enclosed by the central trajectory, the boundary lines on both sides, and the length range between the cutting position and the cutting position is defined as the heat-affected zone on both sides of the cutting segment.

[0039] Using the cutting plane where the current cutting segment is located as a reference plane, the heat-affected zone is projected onto the corresponding solid surface of the workpiece along the normal direction of the reference plane. The projected coverage area and the cut itself together constitute the clamping area of ​​the cutting segment.

[0040] If the displacement of the clamp corresponding to a certain position does not exceed the maximum stroke of the clamp, and the effective contact width of the jaws falls completely within the surface of the workpiece when the position is the clamping center, and does not overlap with the cut, hole, or restricted clamping area, then the position is determined as an reachable point; the connected region formed by the continuously distributed reachable points is determined as a candidate clamping region.

[0041] The preset heat-affected zone width can be obtained through experimental calibration. Specifically, on a test piece with the same material and thickness as the workpiece to be processed, a test cutting trajectory is executed using the laser power, cutting speed, pulse frequency, defocusing amount and auxiliary gas pressure corresponding to the current cutting segment. The width of the area where the metallographic structure changes on both sides of the cut is measured, and 1.2 times the width of the area is taken as the preset heat-affected zone width.

[0042] In the workpiece coordinate system, the length direction of the workpiece to be processed is taken as the segmentation reference direction, and each candidate clamping area is projected along the length direction into several candidate intervals. Then, the effective contact width of the gripper is used as the segment length, and each candidate interval is continuously divided to obtain multiple candidate segments. When the remaining length at the end of the candidate interval is less than the effective contact width of the gripper, the remaining part is merged into the last adjacent complete candidate segment.

[0043] For each candidate segment, the cross section corresponding to its center position is taken as the evaluation cross section, and a unit load is applied in the direction perpendicular to the current cutting plane. The displacement of the evaluation cross section is calculated, and the ratio of the unit load to the displacement is recorded as the local stiffness of the candidate segment. When the candidate segment corresponds to a cutting segment with different orientations, a load can be applied along the normal direction of the corresponding cutting segment and the corresponding local stiffness can be calculated.

[0044] Calculate the distance along the length of the workpiece from the center position of the candidate segment to the nearest stable support position, and record this distance as the cantilever length of the candidate segment. The stable support position includes the support positions at both ends of the workpiece, the selected clamping point, and the structural position that is continuously connected to the uncut body.

[0045] The ratio of local stiffness to cantilever length is used as the support evaluation value. Candidate segments are sorted in descending order of support evaluation value. Under the condition that the distance between adjacent clamping points is not less than the outer width of the clamp, the candidate segments with the highest ranking are selected in turn, and the center position of each selected candidate segment is determined as multiple clamping points.

[0046] Reference Figure 2 As shown, in a preferred embodiment of the present invention, the process of dividing the processing path into multiple cutting segments and performing laser straight cutting segment by segment is specifically as follows: The path segments are traversed and merged according to the execution order of the processing program.

[0047] When adjacent path segments are directly connected and extend in the same direction, the corresponding path segments are merged into the same cutting segment; when adjacent path segments are jump-connected, intersecting, or extend in different directions, the current merging ends and an independent cutting segment is formed, thus obtaining multiple cutting segments.

[0048] Subsequently, the execution order is determined according to the positional order of each cutting segment in the feed direction, and the starting end of each cutting segment is taken as the entry position and the ending end as the exit position.

[0049] When executing the current cutting segment, the laser head is controlled to continuously feed from the entry position to the exit position to complete the laser straight cut of the current cutting segment; after the current cutting segment is completed, the clamping fixture involved in the current cutting segment is controlled to move along the feed direction to the starting position of the next segment to be processed, and after a stable clamping is formed, the laser straight cut of the next cutting segment is executed until all cutting segments are processed.

[0050] S2. After the current cutting segment is completed, the fixture that is holding the current cutting segment will be moved along the feed direction to the starting position of the next segment to be processed. Taking the end position of the completed cutting segment in the workpiece coordinate system as the reference, the distance between the moving endpoint and the end of the completed cutting segment along the feed direction shall not be less than the preset heat-affected zone width under the current laser process parameters.

[0051] It is understandable that after laser straight cutting, the metallographic structure and mechanical properties of the material in the heat-affected zone on both sides of the cut have changed. If the fixture is used to clamp the material in the heat-affected zone, on the one hand, the hardness and yield strength of the material in the heat-affected zone are different from those of the base material, and the local deformation behavior under the clamping force is uncontrollable, which can easily introduce secondary clamping errors.

[0052] On the other hand, the heat-affected zone continues to release residual thermal stress during the cooling process. Applying severe external constraints at this time may induce additional deformation or microcracks, reducing the quality of the finished workpiece. Therefore, setting the end point of the fixture movement outside the preset width range of the heat-affected zone allows sufficient cooling and stress release space to be reserved for the heat-affected zone during the fixture connection process of adjacent cutting segments. This avoids the fixture directly applying force to the material in the heat-affected zone, thereby ensuring that the next segment to be processed is reliably clamped in a stable, heat-undisturbed base material area, and ensuring the consistency of the constraint state between each processing stage.

[0053] Reference Figure 3 As shown, S3, the end of the workpiece to be processed is clamped by a rotating fixture, and the workpiece is driven to rotate around its own axis to obtain the spatial coordinates of three non-collinear feature points on the intersection contour of the surface to be mated and the workpiece to be processed, and the beveling process spatial trajectory is determined based on this to perform beveling cutting.

[0054] The process of obtaining the spatial coordinates of three non-collinear feature points on the intersection contour of the mating surface and the workpiece is as follows: During the process of the rotary fixture driving the workpiece to rotate around its own axis, the contour data of the area where the mating surface intersects with the workpiece is collected by a laser contour sensor. The mating surface refers to the mating surface on the target component that is assembled and connected with the workpiece.

[0055] It should be noted that the method of clamping the end of the workpiece with a rotating fixture and driving the workpiece to rotate around its own axis is preferably suitable for shaft-type steel structural parts or tubular steel structural parts with a defined axis.

[0056] The contour data is denoised and the coordinates are unified. The contour points are projected onto three coordinate planes under the workpiece coordinate system. The coordinate axis with the largest projection length is selected as the initial main extension direction, and the contour points are sorted in ascending order of their coordinate values ​​in this direction. The contour point with the smallest coordinate value in the sorted contour point sequence is determined as the starting position, and the contour point with the largest coordinate value is determined as the ending position.

[0057] Using the line connecting the starting and ending positions as the baseline, calculate the vertical distance from the remaining contour points to the baseline, and select the contour point with the largest vertical distance as the intermediate transition position; when there are multiple candidate points, select the candidate point with the largest curvature value as the intermediate transition position.

[0058] The contour points at the starting position, intermediate transition position, and ending position are respectively designated as the starting feature point, intermediate feature point, and ending feature point.

[0059] It should be noted that the above method of selecting a single intermediate transition position based on the principle of maximizing vertical distance is applicable to situations where the intersecting contours are in a single-peak curved shape. When the intersecting contours exhibit multi-peak curvature or S-shaped trends in the actual collected data, the positions of each peak can be identified sequentially along the main extension direction, and the corresponding intermediate transition points can be selected respectively. The feature plane and beveling trajectory can then be constructed in segments based on each intermediate transition point.

[0060] Obtain the spatial coordinates of the starting feature point, the middle feature point, and the ending feature point in the workpiece coordinate system. Using the starting feature point as the common starting point, calculate the differences between the middle feature point and the starting feature point, and between the ending feature point and the starting feature point, in each spatial coordinate component. Combine the differences into the first eigenvector and the second eigenvector, respectively.

[0061] The components of the first and second eigenvectors in the three coordinate directions are cross-combined to obtain the three components of the vector product. If all three components are non-zero, it indicates that the first and second eigenvectors are not collinear, thus determining that the three feature points form a non-collinear distribution.

[0062] Otherwise, the three feature points are determined to be collinearly distributed.

[0063] Take the components of the two feature vectors on each coordinate axis respectively, perform cross-combination operation, and take the direction vector that is perpendicular to the first feature vector and the second feature vector as the normal vector. With the starting feature point as the reference point and the normal vector as the plane direction constraint, construct a feature plane that passes through the starting feature point, the middle feature point and the ending feature point.

[0064] It should be noted that if the result of the cross-combination operation in the feature vectors is a zero vector, it means that the two feature vectors have not formed an effective plane. The middle feature point should be reselected until the result of the cross-combination operation is not a zero vector.

[0065] Within the feature plane, the line connecting the starting feature point and the ending feature point is used as the reference line, and the direction from the starting feature point to the ending feature point is determined as the main extension direction.

[0066] Project the central feature point vertically onto the reference line to obtain the projection point, and calculate the vertical distance between the central feature point and the projection point. Determine the deflection direction of the intersecting contour based on the lateral position of the central feature point relative to the reference line.

[0067] When the vertical distance is zero, the intersecting profile is determined to transition in a straight line along the main extension direction. When the vertical distance is not zero, the magnitude of the vertical distance characterizes the transition range of the intersecting profile from the reference line. The deflection direction is taken as the lateral offset direction of the intersecting profile, and the transition range is taken as the maximum offset of the intersecting profile at the middle feature point. The offset of the intersecting profile relative to the reference line gradually increases from zero at the starting feature point to the maximum value at the middle feature point along the main extension direction, and then gradually decreases from the maximum value at the middle feature point to zero at the ending feature point. This determines the transition extension trend of the intersecting profile.

[0068] Obtain the contour length along the main extension direction between the starting feature point and the ending feature point, and calculate the sampling interval based on the current feed speed of the laser head and the interpolation cycle.

[0069] Subsequently, starting from the initial feature point, multiple sampling positions are sequentially determined along the main extension direction according to the sampling interval, and a sampling section perpendicular to the main extension direction is established at each sampling position; each sampling section is matched with the intersecting contour data to obtain the corresponding sampling point, and the spatial coordinates of each sampling point in the workpiece coordinate system are obtained.

[0070] Next, project each sampling point vertically onto the feature plane to obtain the corresponding projection point, and calculate the directed distance of each sampling point relative to the feature plane.

[0071] Using the position of the projection point in the feature plane as the planar positioning reference of the bevel processing trajectory point, and using the directed distance as the normal position correction amount of the corresponding bevel processing trajectory point, bevel processing trajectory points corresponding one-to-one with each sampling point are generated.

[0072] Finally, the bevel processing trajectory points are connected according to the arrangement order of each sampling point along the main extension direction. A cubic B-spline curve is used to smoothly fit the transition segment between adjacent bevel processing trajectory points to obtain a continuous bevel processing spatial trajectory.

[0073] S4. During the entire laser straight cutting and bevel cutting process, the deformation deflection of the workpiece is acquired in real time. If the change exceeds the preset threshold, a compensation amount is generated based on the change to correct the processing trajectory and laser pulse frequency of the subsequent unprocessed cutting segment.

[0074] The process of acquiring the deformation deflection of the workpiece in real time is as follows: Using the length axis in the workpiece coordinate system as the reference for point layout, the sections between adjacent clamping points and between the clamping points and the end of the workpiece under the current clamping state are defined as free spans, and the midpoint along the length direction of each free span is taken as the deflection detection position; displacement detection units are fixedly installed on the equipment frame at the corresponding positions of each deflection detection position, so that the measurement direction of each displacement detection unit is perpendicular to the initial surface of the workpiece.

[0075] Before processing begins, after all fixtures are clamped and stabilized, each displacement detection unit is controlled to synchronously collect surface displacement data at the corresponding deflection detection position, and the displacement measurement values ​​within one sampling period are taken as an arithmetic mean. Then, combined with the installation reference coordinates of each displacement detection unit in the workpiece coordinate system, the coordinate conversion of the arithmetic mean displacement measurement values ​​is performed to obtain the initial position data corresponding to each deflection detection position.

[0076] During the processing of each cutting segment, each displacement detection unit is controlled to synchronously collect surface displacement data of the corresponding deflection detection position according to the interpolation cycle, and the current position data corresponding to each deflection detection position is obtained by using the same coordinate conversion method as the initial position data.

[0077] During the movement of the clamp, after the clamp has completed the release, forward movement and re-clamping, the free spans are redefined based on the updated clamping points, and the midpoint of each free span is taken as the current deflection detection position. Then, the displacement detection unit corresponding to the current deflection detection position is called to collect surface displacement data again, and the updated current position data is calculated. At the same time, the displacement data collected after this re-clamping is used as the updated initial position data of the detection position for subsequent calculation of local deflection.

[0078] The current position data and the corresponding initial position data of each deflection detection position are uniformly mapped to the same workpiece coordinate system, and the detection direction of each deflection detection position is used as the reference direction for deflection calculation. The coordinate component difference between the current position and the initial position of each deflection detection position along the detection direction is calculated, and the coordinate component difference is determined as the local deflection value of the corresponding deflection detection position.

[0079] The absolute values ​​of the local deflection values ​​corresponding to each deflection detection position are compared, and the local deflection value with the largest absolute value is selected as the overall deformation deflection of the workpiece at the current sampling time, which represents the maximum deformation degree at the most unfavorable position under the current processing state.

[0080] The overall deformation deflection at the current sampling time is compared with the overall deformation deflection at the previous sampling time. The difference between the two is calculated, and the absolute value of the difference is taken as the change range of the deformation deflection of the workpiece.

[0081] The process of generating compensation based on the change amplitude is as follows: First, the change amplitude of the deformation deflection of the workpiece obtained at the current sampling time is compared with a preset threshold; when the change amplitude of the deformation deflection is greater than the preset threshold, it is determined that the workpiece has undergone deformation offset that needs to be compensated in the current processing state.

[0082] It should be noted that the preset threshold was determined through experimental calibration. Specifically, before the actual processing, the workpiece is kept in the same clamping state as the actual processing, and the laser head is controlled to perform one processing along the corresponding cutting segment. During the processing, the current position data of each deflection detection position is collected synchronously, and the baseline change amplitude sequence corresponding to the continuous sampling time is obtained according to the aforementioned calculation method of local deflection value, overall deformation deflection, and deformation deflection change amplitude. The maximum value in the baseline change amplitude sequence is taken as the preset threshold.

[0083] The absolute values ​​of the local deflection values ​​corresponding to all deflection detection positions are compared. The deflection detection position corresponding to the local deflection value with the largest absolute value is determined as the target deflection detection position in the current processing state. If there are two or more deflection detection positions with the same absolute value of local deflection, the position closer to the current cutting segment along the feed direction is taken as the target deflection detection position.

[0084] Unify the current position data of the target deflection detection position under the current processing state with the initial position data into the same workpiece coordinate system, extract the coordinate components of the two along the deflection detection direction, calculate the coordinate difference between the current position data and the initial position data, and determine the absolute value of the coordinate difference as the deformation offset.

[0085] When the coordinate difference is greater than zero, it is determined that the workpiece has deformed and shifted in the positive direction of the deflection detection direction; when the coordinate difference is less than zero, it is determined that the workpiece has deformed and shifted in the negative direction of the deflection detection direction; when the coordinate difference is equal to zero, it is determined that the target deflection detection position has not deformed and shifted.

[0086] A deformation compensation vector is constructed with the deformation offset as the modulus and the deformation offset direction as the direction. The deformation compensation vector is projected along each coordinate axis of the workpiece coordinate system to obtain the trajectory offset components in each coordinate axis direction. The trajectory offset components are then combined as the first trajectory compensation amount.

[0087] The actual positioning position of the fixture in the workpiece coordinate system is obtained by the displacement sensor, which is involved in clamping the current cutting segment and moving to the next segment to be processed.

[0088] The coordinate components of the target end position corresponding to the actual positioning position and the starting position of the next segment to be processed are compared in each coordinate axis direction to obtain the positioning deviation value in each coordinate axis direction, and this value is used as the second trajectory compensation amount. The first trajectory compensation amount and the second trajectory compensation amount are vector superimposed in the same workpiece coordinate system to obtain the trajectory compensation amount for the subsequent unprocessed cutting segment.

[0089] Read the laser pulse frequency corresponding to the original processing program of the current unprocessed cutting segment and record it as the reference frequency.

[0090] The trajectory compensation amount is projected along the laser beam axis to obtain the focal relative offset. The thickness of the workpiece is used as the normalization reference, and the ratio of the focal relative offset to the workpiece thickness is determined as the frequency correction coefficient. The product of the reference frequency and the frequency correction coefficient is used as the laser pulse frequency compensation amount.

[0091] When the direction of the relative focal offset is away from the laser head, the laser pulse frequency compensation is set to a positive value; when the direction of the relative focal offset is towards the laser head, the laser pulse frequency compensation is set to a negative value; when the relative focal offset is zero, the laser pulse frequency compensation is set to zero.

[0092] It should be noted that when the workpiece is deformed and shifts axially, the position of the laser focus relative to the workpiece surface changes, causing the actual energy density acting on the kerf to deviate from the preset value. The frequency correction coefficient is used to characterize the pulse frequency adjustment ratio corresponding to the degree of energy density deviation. When the focus shifts away from the laser head, the pulse frequency needs to be increased to compensate for energy dispersion. When the focus shifts towards the laser head, the pulse frequency needs to be reduced to avoid overheating.

[0093] The process of correcting the processing trajectory and laser pulse frequency of the subsequent unprocessed cutting segment is as follows: Read the entry position, exit position and intermediate trajectory points in the original machining trajectory of the subsequent unprocessed cutting segment, and obtain the compensation components of the trajectory compensation in each coordinate axis direction of the workpiece coordinate system.

[0094] The entry position, exit position, and each intermediate trajectory point are each corrected by coordinate correction. That is, according to the component and sign of the trajectory compensation amount in the corresponding coordinate axis direction, the coordinate values ​​of each trajectory point on the corresponding coordinate axis are corrected along the compensation direction. The compensation direction is opposite to the deformation offset direction to offset the generated deformation offset, while the coordinate values ​​of the coordinate axes not involved in the compensation remain unchanged. After all trajectory points are corrected, the original arrangement order of each trajectory point is kept unchanged, and the corrected entry position, each corrected intermediate trajectory point, and the corrected exit position are connected in sequence to obtain the corrected machining trajectory.

[0095] The reference frequency is used as the correction reference, and the laser pulse frequency compensation is algebraically superimposed with the correction reference according to its positive and negative values ​​to obtain the corrected laser pulse frequency. If the corrected laser pulse frequency exceeds the laser's allowable output range, the corresponding upper or lower limit value is taken as the final execution frequency.

[0096] In a preferred embodiment of the present invention, a collaborative control method integrating laser cutting and beveling of steel structures further includes: The laser head is controlled to process the subsequent unprocessed cutting segments according to the corrected processing trajectory and the corrected laser pulse frequency; during the processing, the deformation and deflection of the workpiece are continuously acquired and its change range is calculated.

[0097] When the change amplitude is not greater than the preset threshold, the current processing trajectory and laser pulse frequency are maintained and processing continues; when the change amplitude is greater than the preset threshold, the laser head is controlled to pause light output after completing the trajectory segment corresponding to the current interpolation cycle, and the pause position is recorded as the breakpoint position. The unexecuted trajectory after the current pause position is taken as the remaining unprocessed cutting segment, and the compensation amount is regenerated based on the current deformation state and the actual positioning state of the fixture. The processing trajectory and laser pulse frequency of the remaining unprocessed cutting segment are corrected again and processing continues until all subsequent unprocessed cutting segments are processed.

[0098] The subsequent unprocessed cutting segments include at least one cutting segment that will be executed immediately after the current cutting segment is completed. Furthermore, the trajectory correction operation for the next cutting segment to be executed is completed before the fixture involved in holding the current cutting segment is moved to the starting position of the next segment to be processed in step S2.

[0099] It should be noted that the current deformation state is calculated using the current position data obtained last time before the start of this correction and the corresponding initial position data. The initial position data is consistent with the initial position data used in the aforementioned S4 step to ensure the continuity of deformation calculation.

[0100] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined by the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A collaborative control method integrating laser cutting and beveling of steel structures, characterized in that, include, Based on the processing path, determine multiple clamping points on the workpiece to be processed, and use no less than two fixtures to implement multi-point clamping, divide the processing path into multiple cutting segments and perform laser straight cutting segment by segment; After the current cutting segment is completed, the fixture that is used to hold the current cutting segment will be moved along the feed direction to the starting position of the next segment to be processed. The distance between the end position of the completed cutting segment in the workpiece coordinate system and the end position of the completed cutting segment along the feed direction shall not be less than the preset heat-affected zone width under the current laser process parameters. The end of the workpiece is held by a rotating fixture, and the workpiece is driven to rotate around its own axis. The spatial coordinates of three non-collinear feature points on the intersection contour of the surface to be fitted and the workpiece are obtained, and the beveling process spatial trajectory is determined based on this to perform beveling cutting. The deformation and deflection of the workpiece are acquired in real time throughout the laser straight cutting and bevel cutting process. If the change exceeds the preset threshold, a compensation amount is generated based on the change to correct the processing trajectory and laser pulse frequency of the subsequent unprocessed cutting segment.

2. The integrated control method for laser cutting and beveling of steel structures according to claim 1, characterized in that, The process of determining multiple clamping points on the workpiece based on the machining path is as follows: Obtain the structural dimensions, machining path, and fixture travel information of the workpiece to be processed; The trajectory data in the processing path is analyzed to extract the starting coordinates, ending coordinates, extension direction, and connection relationship between adjacent path segments. The starting coordinates of the path segment determine the entry position of the corresponding cutting segment, and the ending coordinates of the path segment determine the exit position of the corresponding cutting segment. Based on the preset heat-affected zone width corresponding to the current laser process parameters, determine the heat-affected zone coverage area on both sides of the corresponding cutting segment; The area outside the heat-affected zone that meets the clamping accessibility criteria is identified as the candidate clamping area; The candidate clamping area is segmented and screened according to the length direction of the workpiece. The ratio of the local stiffness of each candidate segment to the cantilever length is calculated as the support evaluation value. Combined with the condition that the distance between adjacent clamping points is not less than the outer width of the jaw, the candidate segments with the highest support evaluation values ​​are selected in sequence, and the center position of each selected candidate segment is determined as multiple clamping points.

3. The integrated control method for laser cutting and beveling of steel structures according to claim 1, characterized in that, The process of dividing the processing path into multiple cutting segments and performing laser straight cutting segment by segment is specifically as follows: Based on the starting coordinates, ending coordinates, extension direction, and connection relationship between adjacent path segments in the processing path, the processing path is segmented to obtain multiple cutting segments. The execution order of each cutting segment is determined based on the time sequence and spatial position constraints of the fixtures participating in the current cutting segment moving to the starting position of the next segment to be processed after the current cutting segment is completed. When executing the current cutting segment, the laser head is controlled to continuously feed from the entry position to the exit position of the current cutting segment to complete the laser straight cut; After the current cutting segment is completed, the fixture involved in the current cutting segment is controlled to move along the feed direction, and after a stable clamping is formed in the next segment to be processed, the laser straight cut of the next cutting segment is executed.

4. The integrated control method for laser cutting and beveling of steel structures according to claim 1, characterized in that, The process of obtaining the spatial coordinates of three non-collinear feature points on the intersection contour of the mating surface and the workpiece is as follows: During the process of the rotary fixture driving the workpiece to rotate around its own axis, the contour data of the area where the mating surface intersects with the workpiece is collected; Extract the starting position, intermediate transition position and ending position of the intersecting contours based on the contour data, and determine the contour points at the corresponding positions as the starting feature point, intermediate feature point and ending feature point respectively; Obtain the spatial coordinates of the three feature points in the workpiece coordinate system, and determine whether the three feature points are non-collinearly distributed; If so, the spatial coordinates of the three feature points are used as the representation data of the spatial attitude of the surface to be fitted, and the spatial trajectory of the beveling process is determined.

5. The integrated control method for laser cutting and beveling of steel structures according to claim 4, characterized in that, The process of determining whether the three feature points constitute a non-collinear distribution is as follows: Based on the spatial coordinates of the starting feature point, the middle feature point, and the ending feature point, construct a first feature vector pointing from the starting feature point to the middle feature point and a second feature vector pointing from the starting feature point to the ending feature point. Calculate the vector product of the first eigenvector and the second eigenvector. If the vector product is not zero, then the three feature points are determined to be non-collinearly distributed. Otherwise, the three feature points are determined to be collinearly distributed.

6. The integrated control method for laser cutting and beveling of steel structures according to claim 5, characterized in that, The process of determining the spatial trajectory for beveling is as follows: Based on the spatial coordinates of the starting feature point, the middle feature point, and the ending feature point in the workpiece coordinate system, construct a feature plane passing through the starting feature point, the middle feature point, and the ending feature point; Within the feature plane, the main extension direction of the intersecting contour is determined according to the direction of the line connecting the starting feature point to the ending feature point, and the transition extension trend of the intersecting contour is determined according to the position offset of the middle feature point relative to the connecting line. Multi-point sampling is performed on the intersecting contours along the main extension direction to obtain the spatial coordinates of each sampling point in the workpiece coordinate system, and the corresponding beveling trajectory points are generated based on the spatial position of each sampling point relative to the feature plane. The beveling trajectory points are connected according to the sampling order, and the transition segment between adjacent beveling trajectory points is smoothly fitted to obtain a continuous beveling spatial trajectory.

7. The integrated control method for laser cutting and beveling of steel structures according to claim 1, characterized in that, The process of acquiring the deformation deflection of the workpiece in real time is as follows: Multiple deflection detection positions are set along the length of the workpiece, and the initial position data corresponding to each deflection detection position is obtained before the processing begins. During the processing of each cutting segment and the movement of the fixture, the current position data corresponding to each deflection detection position is acquired in real time; Based on the coordinate difference between the current position data and the initial position data at each deflection detection location, the local deflection value at each deflection detection location is determined. The maximum absolute value among the local deflection values ​​is selected as the overall deformation deflection of the workpiece under the current processing state. The absolute value of the difference between the overall deformation deflection under the current processing state and the overall deformation deflection corresponding to the previous sampling time is taken to obtain the change range of the deformation deflection of the workpiece.

8. The integrated control method for laser cutting and beveling of steel structures according to claim 7, characterized in that, The process of generating the compensation amount based on the change amplitude is as follows: When the change in deformation deflection exceeds the preset threshold, the detection position corresponding to the maximum local deflection is obtained, and its current position data is compared with the initial position data to obtain the corresponding coordinate difference. The direction of deformation offset is determined according to the sign of the coordinate difference, and the absolute value of the coordinate difference is used as the deformation offset. The deformation offset is projected along the deformation offset direction onto the corresponding coordinate axis of the workpiece coordinate system to obtain the trajectory offset value, which is then used as the first trajectory compensation amount. The actual positioning position of the fixture, which participates in the current cutting segment clamping and moves along the feed direction, in the workpiece coordinate system is obtained by the displacement sensor. The actual positioning position is compared with the target final position corresponding to the starting position of the next segment to be processed to obtain the positioning deviation value; The positioning deviation value is used as the second trajectory compensation amount, and it is vector-superimposed with the first trajectory compensation amount to obtain the trajectory compensation amount for the subsequent unprocessed cutting segment. Using the laser pulse frequency corresponding to the current unprocessed cutting segment as the reference frequency, the trajectory compensation amount is projected along the laser beam axis to obtain the focal relative offset. Using the thickness of the workpiece as the normalization reference, the ratio of the focal relative offset to the workpiece thickness is used as the frequency correction coefficient. The product of the reference frequency and the frequency correction coefficient is used as the laser pulse frequency compensation amount.

9. The integrated control method for laser cutting and beveling of steel structures according to claim 8, characterized in that, The process of correcting the processing trajectory and laser pulse frequency of the subsequent unprocessed cutting segment is as follows: The entry and exit positions and intermediate trajectory points in the original machining trajectory of the subsequent unprocessed cutting segment are corrected in the workpiece coordinate system along the component directions of the trajectory compensation amount on each coordinate axis of the workpiece coordinate system. The correction direction is opposite to the deformation offset direction, thus obtaining the corrected machining trajectory. Using the reference frequency as the correction reference, the reference frequency and the laser pulse frequency compensation amount are algebraically superimposed to obtain the corrected laser pulse frequency.

10. The integrated control method for laser cutting and beveling of steel structures according to claim 9, characterized in that, Also includes: The laser head is controlled to process the subsequent unprocessed cutting segments according to the corrected processing trajectory and the corrected laser pulse frequency; During the subsequent processing of the unprocessed cutting segment, the deformation deflection of the workpiece to be processed is continuously acquired. If the change still exceeds the preset threshold, the compensation amount is regenerated for the remaining unprocessed cutting segment and corrected again.

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