Laser processing error compensation method and processing system

Abstract

The invention discloses a laser processing error compensation method and a processing system, and the method comprises the following steps: based on target processing graphic data, setting a decomposition step length and a galvanometer refresh cycle of laser processing, and planning a target axis track and a target galvanometer track; before machining is started, the shaft is driven to move along a preset empty track, actual motion coordinate information on a plurality of preset points is recorded, and coordinate information of the next point position of the shaft is predicted according to the coordinate information; calculating deviation information based on the actual coordinate information of the current point location on the target axis track, and correcting the track between the current point location and the next point location of the axis by using the deviation information; obtaining the correction information of the galvanometer on the corresponding galvanometer track based on the correction information of the track between the current point location and the next point location of the shaft; and the correction information of the galvanometer is issued to the galvanometer to compensate the actual position of the galvanometer, and then laser machining is started. Various machining errors are effectively compensated, and the machining precision and the product quality are improved.

Description

Technical Field

[0001] This invention belongs to the field of laser processing technology, specifically relating to a laser processing error compensation method and processing system. Background Technology

[0002] Laser processing technology, with its advantages of non-contact operation, high efficiency, and high precision, is widely used in industrial production. However, with the increasing size of processed parts, especially for large-format workpieces, a single laser processing module (such as a galvanometer system or a gantry system) is insufficient to meet the demands of the processing area. To achieve large-format processing, a linkage between the gantry system and the galvanometer system is typically used; the gantry axis handles the large-scale movement, while the galvanometer system performs high-speed scanning over a smaller area.

[0003] However, during the linkage between the gantry axis and the galvanometer system, especially when switching galvanometer scanning areas or splicing different areas, various processing errors, such as splicing errors, dimensional errors, and deformation errors, are easily generated due to the superposition of factors such as mechanical motion errors, galvanometer calibration errors, laser parameter fluctuations, ambient temperature changes, and transformation errors between multiple coordinate systems. The existence of these errors seriously affects the accuracy and product quality of large-format laser processing, leading to increased scrap rates and reduced processing efficiency.

[0004] Existing error compensation methods mainly focus on error correction of a single system, or employ offline calibration and manual adjustment. However, for large-format machining involving the linkage of gantry shafts and galvanometers, especially for online compensation under high precision and high dynamic range conditions, there is still a lack of effective and robust solutions. Traditional compensation methods often fail to capture and correct complex dynamic errors in real time, resulting in unsatisfactory compensation effects. Therefore, developing a high-precision, high-efficiency, and adaptive laser processing error compensation method is of great significance for improving the quality and efficiency of large-format laser processing. Summary of the Invention

[0005] The purpose of this invention is to address the machining error problem caused by the linkage between the gantry and the galvanometer in existing large-format laser processing, and to provide a high-precision, high-efficiency, and adaptive laser processing error compensation method and processing system to effectively compensate for various processing errors and improve processing accuracy and product quality.

[0006] To achieve the above objectives, a specific embodiment of the present invention provides a laser processing error compensation method, the method comprising the following steps: Based on the target processing graphic data, the decomposition step size and galvanometer refresh cycle of laser processing are set, and the target axis trajectory and target galvanometer trajectory are planned. Before processing begins, the shaft is driven to move along a preset empty trajectory and the actual motion coordinate information at several preset points is recorded. Based on the coordinate information, the coordinate information of the next point of the shaft is predicted. Based on the actual coordinate information of the current point on the target axis trajectory, the deviation information is calculated, and the deviation information is used to correct the trajectory between the current point and the next point on the axis. Based on the correction information of the trajectory between the current point and the next point of the axis, the correction information of the galvanometer on the corresponding galvanometer trajectory is obtained; The correction information of the galvanometer is sent to the galvanometer to compensate for its actual position, and then laser processing begins.

[0007] In one or more embodiments of the present invention, the step of predicting the coordinate information of the next point on the axis includes: A set is established, which includes moving along a preset empty trajectory and recording the actual motion coordinate information at several preset points. Based on the actual motion coordinates in the set, the actual motion trajectory curve of the axis is fitted. Based on the target axis trajectory and the actual motion trajectory curve, predict the coordinate information of the axis at the next point.

[0008] In one or more embodiments of the present invention, correcting the trajectory between the current point and the next point of the axis includes: Based on the decomposition step size and galvanometer refresh cycle, the axis sub-coordinates with an equal number of galvanometer refresh cycles are decomposed at the current point and the next point of the axis. The axis error is obtained based on the actual coordinates of the current point and the coordinates of the current point on the target axis trajectory. The coordinates of each axis sub-axis are then corrected based on the error.

[0009] In one or more embodiments of the present invention, the compensation for the actual position of the galvanometer includes: Establish the correspondence between the axis coordinates and the galvanometer point coordinates within the galvanometer refresh cycle; Based on the coordinate information of the graphic target track at the current and next points and the position information of the axis coordinates, the galvanometer coordinate information within the current galvanometer refresh cycle is corrected and supplemented.

[0010] In one or more embodiments of the present invention, during the movement of the shaft, the set updates its internal data points in real time. After calculating the galvanometer compensation point information, the point that first entered the set cache is deleted, and the next latest point is stored.

[0011] In one or more embodiments of the present invention, the actual motion coordinate information of the plurality of preset points is recorded by a point-time controller, and the actual motion coordinate information includes the coordinates, velocity, acceleration and motion error of the point.

[0012] In one or more embodiments of the present invention, the decomposition step size is 1ms and the galvanometer refresh period is 10us.

[0013] In one or more embodiments of the present invention, the set contains at least six consecutive preset points with axis coordinate information.

[0014] In one or more embodiments of the present invention, the motion error of the axis includes motion errors in the X and Y directions, and the motion error is the difference between the axis coordinates of the current actual position and the axis coordinates of the corresponding position of the target axis trajectory.

[0015] In another aspect of the present invention, a laser processing system is provided, the system being used to implement the above-described laser processing error compensation method, comprising: A laser is used to generate a laser beam. The laser processing head has a built-in galvanometer system for receiving control commands and precisely controlling the scanning path and focal position of the laser beam; The gantry system includes X, Y, and Z axis motion modules that carry the laser processing head and are used to achieve coarse positioning and coordinated movement within a large area. The EtherCAT bus is used to connect the laser, the galvanometer controller in the laser processing head, the gantry shaft motion controller, various sensors, data acquisition modules and the host computer to ensure high-speed and high synchronization of data transmission. Multiple sensors are used to collect motion data of the gantry shaft and the galvanometer, the working status of the laser, environmental parameters, and error data of the workpiece or processing area in real time; The controller, including the gantry shaft motion controller and the galvanometer motion controller, acts as an EtherCAT slave station to receive motion commands and real-time compensation values ​​sent by the host computer and to precisely control the execution of their respective motion systems. The host computer is used to receive the sensor data, run the error compensation model, calculate the real-time compensation amount, and send motion commands and compensation commands to the controller.

[0016] Compared with the prior art, the laser processing error compensation method of the present invention predicts the axis position information of the next point by planning the target axis trajectory and the target galvanometer trajectory and recording the actual axis position information. At the same time, it corrects the axis trajectory within the same galvanometer refresh cycle according to the error information. Based on the following relationship between the axis and the galvanometer, it applies 100 sets of correction data of the axis between two points to the correction of the galvanometer coordinates through the mapping relationship, thereby improving the accuracy of laser processing.

[0017] The mechanical processing system linked to the laser processing system in this invention possesses an unlimited field of view and can synchronously operate a linear servo axis and a laser scanning galvanometer. When the high dynamic performance of the scanning galvanometer is combined with the large stroke range of the servo platform, it can continuously process a larger working range than traditional galvanometers without the need for splicing working areas. The linked laser system not only expands the working range of the scanning galvanometer system and the application range of individual optical components, but also avoids the mutual interference between the laser beam range and the usable working range, improving the accuracy of large-area processing. This, in turn, improves processing quality and the production of large parts. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a laser processing error compensation method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the trajectory in one embodiment of the present invention; Figure 3 for Figure 2 Medium magnified view; Figure 4 This is a schematic diagram of trajectory compensation in one embodiment of the present invention; Figure 5 This is a schematic diagram of a cached coordinate set according to one embodiment of the present invention; Figure 6 This is a schematic diagram of fitting the axial coordinate curve in one embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the prediction of the axis coordinates at the next time step according to one embodiment of the present invention; Figure 8 This is a schematic diagram of the galvanometer coordinate compensation step in one embodiment of the present invention; Figure 9 This is a schematic diagram of the galvanometer following axis step in one embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0021] As described in the background section, there is a problem with the machining error caused by the linkage between the gantry axis and the galvanometer in large-format laser processing.

[0022] In response to the above technical problems, such as Figure 1 As shown, this invention introduces a laser processing error compensation method, which includes the following steps: Step 1: Based on the target processing graphic data, set the decomposition step size and galvanometer refresh cycle for laser processing, and plan the target axis trajectory and target galvanometer trajectory; Step 2: Before the machining begins, the drive shaft moves along a preset empty trajectory and records the actual motion coordinate information at several preset points. Based on the coordinate information, the coordinate information of the next point of the shaft is predicted. Step 3: Calculate the deviation information based on the actual coordinate information of the current point on the target axis trajectory, and use the deviation information to correct the trajectory between the current point and the next point on the axis; Step 4: Based on the correction information of the trajectory between the current point and the next point of the axis, obtain the correction information of the galvanometer on the corresponding galvanometer trajectory; Step 5: Send the correction information of the galvanometer to the galvanometer to compensate for the actual position of the galvanometer, and then start laser processing.

[0023] In a further embodiment, galvanometer following control is the core of the linkage algorithm. Its main purpose is to compensate for the position of the axis acquired by the galvanometer during the axis's movement in real time. After acquiring the large-format target processing graphic data, the motion trajectory of the axis is first planned, and then the motion position of the galvanometer is calculated based on the axis's motion position. The original trajectory is then subjected to frequency domain transformation, and the low-frequency part is filtered out using a filtering method. The low-frequency part is handled by the axis (motion stage), while the high-frequency part is handled by the galvanometer. In this embodiment, the galvanometer following algorithm is integrated into the motion controller, using an EtherCAT configuration topology connection.

[0024] In a further embodiment, since the axis interpolation period is 1ms, the galvanometer refresh period is set to 10us. However, the system's interpolation period is limited to only 1ms, so the position of the galvanometer needs to be predicted, calculated, and compensated. If there is a deviation between the predicted point position and the actual point position during this process, this error will be immediately included in the next prediction compensation. Each accumulated error will be compensated in the next one, and there will be no accumulation.

[0025] Assuming the decomposition step size is set to 1ms, and the position points of one axis and 100 galvanometers are decomposed every 1ms, the target trajectory decomposed is shown in Table 1 below, including the target trajectory and the target axis trajectory and target galvanometer trajectory decomposed from the target trajectory.

[0026] Table 1. Target Trajectory Decomposition Table

[0027] like Figures 2-9 As shown, the yellow line represents the trajectory of the target graphic to be processed, the blue line represents the trajectory of the axis movement, and the light blue line represents the trajectory of the axis in the air. During this stage, the axis moves to the point to be processed, and no laser is emitted or processing is performed on this path.

[0028] In a further embodiment, the step of predicting the coordinates of the next point on the axis includes: A set is established, which includes moving along a preset empty trajectory and recording the actual motion coordinate information at several preset points. Based on the actual motion coordinates in the set, the actual motion trajectory curve of the axis is fitted. Based on the target axis trajectory and the actual motion trajectory curve, predict the coordinate information of the axis at the next point. Specifically, during the empty trajectory phase of the axis, no laser processing is performed. At this time, a buffer stack of a specified size (e.g., 6 points) is created to store the coordinate information of the axis's movement points. Once the axis reaches the point where processing begins, the controller starts recording the axis's movement point P. t-5 This includes the point (PX) t-5 PY t-5 Coordinates, velocity v t-5 acceleration a t-5 Motion error EX t-5 EY t-5 Record P in the same way. t-4 P t-3 P t-2 P t-1 and P t The information and the recorded results are shown in Table 2 below.

[0029] Table 2. Axis Coordinate Information for Empty Trajectory Phase

[0030] like Figures 4-5 As shown, curve fitting is performed based on the coordinate information of the points moving along the six axes in the table to obtain the equation of the fitted curve. Based on P in the table... t P can be calculated from the velocity and acceleration information of the point. t+1 Point information.

[0031] In a further embodiment, P is divided into 100 equal parts. t To P t+1 Line segments between points yield the motion coordinates PX along 100 axes. t.001 -PX t.100 and PY t.001 -PY t.100 The shaft error EX t and EY t Substitute and correct PXt. 001 -PXt. 100 And PYt. 001 -PYt. 100 .

[0032] In a further embodiment, according to the current P t The coordinates query retrieves the corresponding target trajectory coordinates (RX). t RY t ) and (RX t+1 RY t+1 Then, based on PXt. 001 -PXt. 100 And PYt. 001 -PYt. 100 Correct the coordinate information of the compensation galvanometer point GXt. 001 —GXt. 100 and GYt. 001 —GYt. 100 These points are sent to the galvanometer via a control card, thereby driving the galvanometer's movement and achieving a synchronized movement. This process is handled in real time, with the point set cache stack continuously updated. After calculating the galvanometer compensation point information, the earliest point in the cache is deleted, and the next newest point is added, maintaining a fixed-size cache with constantly updated data. This process is repeated until all target graphics processing is complete.

[0033] like Figure 5 As shown, a system for implementing a laser processing error compensation method according to a specific embodiment of the present invention is described. The system includes: A laser is used to generate a laser beam. The laser processing head has a built-in galvanometer system for receiving control commands and precisely controlling the scanning path and focal position of the laser beam; The gantry system includes X, Y, and Z axis motion modules that carry the laser processing head and are used to achieve coarse positioning and coordinated movement within a large area. The EtherCAT bus is used to connect the laser, the galvanometer controller in the laser processing head, the gantry shaft motion controller, various sensors, data acquisition modules and the host computer to ensure high-speed and high synchronization of data transmission. Multiple sensors are used to collect motion data of the gantry shaft and the galvanometer, the working status of the laser, environmental parameters, and error data of the workpiece or processing area in real time; The controller, including the gantry shaft motion controller and the galvanometer motion controller, acts as an EtherCAT slave station to receive motion commands and real-time compensation values ​​sent by the host computer and to precisely control the execution of their respective motion systems. The host computer is used to receive the sensor data, run the error compensation model, calculate the real-time compensation amount, and send motion commands and compensation commands to the controller.

[0034] This linked laser processing system boasts an unlimited field of view, synchronizing linear servo axes with a laser scanning galvanometer. When the high dynamic performance of the scanning galvanometer is combined with the large stroke range of the servo platform, it can continuously process a larger working range than traditional galvanometers, eliminating the need for splicing working areas. The linked laser system not only expands the working range of the scanning galvanometer system and the application range of individual optical components, but also avoids mutual interference between the laser beam range and the usable working range, improving the accuracy of large-area processing. This, in turn, improves processing quality and the production of large parts.

[0035] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0036] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1One or more processes and / or boxes Figure 1 A system that specifies functions in one or more boxes.

[0037] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including an instruction set implemented in a process. Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0038] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0040] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A laser processing error compensation method, characterized in that, The method includes the following steps: Based on the target processing graphic data, the decomposition step size and galvanometer refresh cycle of laser processing are set, and the target axis trajectory and target galvanometer trajectory are planned. Before the machining begins, the drive shaft moves along a preset empty trajectory and records the actual motion coordinate information at several preset points. Based on the coordinate information, the coordinate information of the next point of the shaft is predicted. Based on the actual coordinate information of the current point on the target axis trajectory, the deviation information is calculated, and the deviation information is used to correct the trajectory between the current point and the next point on the axis. Based on the correction information of the trajectory between the current point and the next point of the axis, the correction information of the galvanometer on the corresponding galvanometer trajectory is obtained; The correction information of the galvanometer is sent to the galvanometer to compensate for its actual position, and then laser processing begins.

2. The laser processing error compensation method according to claim 1, characterized in that, The step of predicting the coordinates of the next point on the axis includes: A set is established, which includes moving along a preset empty trajectory and recording the actual motion coordinate information at several preset points. Based on the actual motion coordinates in the set, the actual motion trajectory curve of the axis is fitted. Based on the target axis trajectory and the actual motion trajectory curve, predict the coordinate information of the axis at the next point.

3. The laser processing error compensation method according to claim 1, characterized in that, The correction of the trajectory between the current point and the next point of the axis includes: Based on the decomposition step size and galvanometer refresh cycle, the axis sub-coordinates with an equal number of galvanometer refresh cycles are decomposed at the current point and the next point of the axis. The axis error is obtained based on the actual coordinates of the current point and the coordinates of the current point on the target axis trajectory. The coordinates of each axis sub-axis are then corrected based on the error.

4. The laser processing error compensation method according to claim 3, characterized in that, The compensation for the actual position of the galvanometer includes: Establish the correspondence between the axis coordinates and the galvanometer point coordinates within the galvanometer refresh cycle; Based on the coordinate information of the graphic target track at the current and next points and the position information of the axis coordinates, the galvanometer coordinate information within the current galvanometer refresh cycle is corrected and supplemented.

5. The laser processing error compensation method according to claim 2, characterized in that, During the movement of the axis, the set updates its internal data points in real time. After calculating the galvanometer compensation point information, the point that first entered the set cache is deleted, and the next latest point is stored.

6. The laser processing error compensation method according to claim 1, characterized in that, The actual motion coordinate information at the preset points is recorded by the point-time controller. The actual motion coordinate information includes the coordinates, velocity, acceleration, and motion error of the point.

7. The laser processing error compensation method according to claim 1, characterized in that, The decomposition step size is 1ms, and the galvanometer refresh period is 10us.

8. The laser processing error compensation method according to claim 2, characterized in that, The set contains the axis coordinate information of at least 6 consecutive preset points.

9. A laser processing error compensation method according to claim 3, characterized in that, The motion error of the axis includes motion errors in the X and Y directions, and the motion error is the difference between the axis coordinates of the current actual position and the axis coordinates of the corresponding position of the target axis trajectory.

10. A laser processing system, characterized in that, The system is used to implement the laser processing error compensation method according to any one of claims 1 to 9, including: A laser is used to generate a laser beam. The laser processing head has a built-in galvanometer system for receiving control commands and precisely controlling the scanning path and focal position of the laser beam; The gantry system includes X, Y, and Z axis motion modules that carry the laser processing head and are used to achieve coarse positioning and coordinated movement within a large area. The EtherCAT bus is used to connect the laser, the galvanometer controller in the laser processing head, the gantry shaft motion controller, various sensors, data acquisition modules and the host computer to ensure high-speed and high synchronization of data transmission. Multiple sensors are used to collect motion data of the gantry shaft and the galvanometer, the working status of the laser, environmental parameters, and error data of the workpiece or processing area in real time; The controller, including the gantry shaft motion controller and the galvanometer motion controller, acts as an EtherCAT slave station to receive motion commands and real-time compensation values ​​sent by the host computer and to precisely control the execution of their respective motion systems. The host computer is used to receive the sensor data, run the error compensation model, calculate the real-time compensation amount, and send motion commands and compensation commands to the controller.

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