Focus compensation method, device and storage medium of coordinate system

Abstract

The application discloses a focal point compensation method and device of a coordinate system and a storage medium, relates to the technical field of laser processing, and comprises the following steps: acquiring the displacement amount of a manipulator relative to a calibration reference point and the deflection angle of a galvanometer when a current processing point is completed; calculating a focal point displacement amount based on the coupling coefficient between the pre-calibrated displacement of the manipulator and the deflection of the galvanometer, the displacement amount and the deflection angle; and controlling an actuator to perform focal point compensation according to the focal point displacement amount, so as to correct the focal point position of a next processing point. The application solves the problem that, when the actual motion track of the manipulator deviates from the calibration track due to load change, temperature drift, servo lag or external disturbance, the pre-stored calibration table cannot reflect the real pose change, resulting in focal point displacement, realizes real-time correction of the focal point in the continuous movement of the manipulator, and effectively improves the processing efficiency and focal point control precision.

Description

Technical Field

[0001] This application relates to the field of laser processing technology, and in particular to a method, apparatus and storage medium for focal compensation of a coordinate system. Background Technology

[0002] Related galvanometer focusing systems typically use a static calibration table for focusing. This means that during the equipment debugging phase, the focal offset corresponding to each coordinate point of the robot arm and each deflection angle of the galvanometer is pre-written into the controller. During processing, compensation is performed by interpolation through table lookup.

[0003] However, when the actual movement trajectory of the robot deviates from the calibrated trajectory due to load changes, temperature drift, servo lag, or external disturbances, the pre-stored calibration table cannot reflect the true pose changes, leading to focus shift. For high-speed continuous machining requirements, the lag of this static calibration method is more pronounced, resulting in larger calibration errors.

[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this application is to provide a coordinate system focus compensation method, device, and storage medium, which aims to solve the technical problem of focus offset when the actual movement trajectory of a robot deviates from the calibrated trajectory.

[0006] To achieve the above objectives, this application proposes a coordinate system focus compensation method, which includes: When the current processing point completes processing, obtain the displacement of the robot relative to the calibration reference point and the deflection angle of the galvanometer; Based on the pre-calibrated coupling coefficient between the robot arm displacement and the galvanometer deflection, the focal offset is calculated using the displacement and the deflection angle. The control actuator performs focus compensation based on the focus offset to correct the focus position of the next processing point.

[0007] In one embodiment, the step of calculating the focal offset based on the pre-calibrated coupling coefficient between the manipulator displacement and the galvanometer deflection, the displacement amount, and the deflection angle includes: The displacement is decomposed into a first component along the optical axis and a second component perpendicular to the optical axis. The second component is determined as the reference focus offset; The coupling focus offset is calculated based on the coupling coefficient, the second component, and the deflection angle. The sum of the reference focus offset and the coupled focus offset is determined as the focus offset.

[0008] In one embodiment, the step of calculating the coupling focus offset based on the coupling coefficient, the second component, and the deflection angle includes: The deflection angles are combined into a deflection angle, and the tangent of the deflection angle is determined. The coupling focus offset is obtained by calculating the product of the coupling coefficient, the tangent value, and the second component.

[0009] In one embodiment, after the step of calculating the coupling focus offset based on the coupling coefficient, the second component, and the deflection angle, the focus compensation method for the coordinate system further includes: The thermal drift compensation value is determined based on the temperature data collected by the temperature sensor. The sum of the reference focus offset, the coupled focus offset, and the thermal drift compensation value is determined as the focus offset.

[0010] In one embodiment, before the step of obtaining the displacement of the robot arm relative to the calibration reference point and the deflection angle of the galvanometer when the current processing point completes processing, the focus compensation method of the coordinate system further includes: Obtain the calibration data combination of multiple sets of manipulator calibration displacement and galvanometer calibration deflection angle contained in the calibration plate; Calculate the actual focus offset corresponding to each set of calibration data; Based on the least squares method, the actual focus offset, the calibration displacement, and the calibration deflection angle of each group are fitted, and the calibration coupling coefficient between the pre-calibrated manipulator displacement and the galvanometer deflection is calculated. The calibration coupling coefficient is used as the coupling coefficient.

[0011] In one embodiment, after the step of obtaining the coupling coefficient between the pre-calibrated manipulator displacement and the galvanometer deflection by fitting each group of actual focus offsets, calibration displacements, and calibration deflection angles using the least squares method, the focus compensation method for the coordinate system further includes: Each processing section is determined based on the movement direction and / or working distance of the robotic arm; Based on the calibration coupling coefficients corresponding to each processing section, the segmented coupling coefficients are calculated. The segmented coupling coefficient is used as the coupling coefficient.

[0012] In one embodiment, before the step of obtaining the calibration data combination of multiple sets of manipulator calibration displacements and galvanometer calibration deflection angles contained in the calibration plate, the focus compensation method of the coordinate system further includes: During the calibration phase, the robot's base coordinate system, galvanometer coordinate system, and laser optical axis coordinate system are constructed. Based on the hand-eye calibration algorithm, a homogeneous transformation matrix from the end flange of the robotic arm to the galvanometer coordinate system is constructed, as well as a transformation matrix from the galvanometer coordinate system to the laser optical axis coordinate system that varies with the galvanometer deflection angle.

[0013] In one embodiment, the actuator includes a focusing module for the galvanometer and a Z-axis fine-tuning module for the robotic arm; the step of controlling the actuator to perform focus compensation based on the focus offset to correct the focus position of the next processing point includes: Determine the first focusing ratio of the focusing module and the second focusing ratio of the Z-axis fine-tuning module; The product of the first focusing ratio and the focus offset is determined as the first adjustment value of the focusing module; The product of the second focusing ratio and the focus offset is determined as the second adjustment value of the Z-axis fine-tuning module; The focusing module is controlled to perform focus compensation based on the first adjustment value, and / or the Z-axis fine-tuning module is controlled to perform focus compensation based on the second adjustment value.

[0014] In addition, to achieve the above objectives, this application also proposes a focus compensation device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the focus compensation method for the coordinate system as described above.

[0015] The technical solution proposed in this application has at least the following technical effects: This application acquires the displacement of the robot arm and the deflection angle of the galvanometer in real time, and dynamically calculates the focus offset based on a pre-calibrated coupling coefficient. This allows for real-time compensation of the actuator. Compared to related technologies that rely on static calibration tables for lookup and interpolation, this application uses the coupling coefficient to calibrate the coupling mapping relationship between the robot arm's displacement perpendicular to the optical axis and the galvanometer deflection along the optical axis. Therefore, even if the robot arm's actual movement trajectory deviates from the calibrated trajectory due to load changes, temperature drift, or external disturbances, this application can still dynamically calculate the true focus offset based on the current real-time pose data and perform online compensation. This solves the technical problem that static calibration tables cannot reflect focus offset caused by dynamic pose changes. Furthermore, since segmented calibration does not need to be paused during processing, this application achieves real-time focus correction during continuous robot arm movement, effectively improving processing efficiency and focus control accuracy. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the first embodiment of the focus compensation method for the coordinate system of this application; Figure 2 This is a simplified flowchart illustrating the calculation of focus offset in the focus compensation method of the coordinate system of this application. Figure 3 This is a simplified flowchart illustrating the focus compensation method in the coordinate system of this application. Figure 4 This is a schematic diagram of the device structure of the hardware operating environment involved in the focus compensation method of the coordinate system in the embodiments of this application.

[0019] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0021] Related galvanometer focusing systems typically use a static calibration table for focusing. This means that during the equipment debugging phase, the focal offset corresponding to each coordinate point of the robot arm and each deflection angle of the galvanometer is pre-written into the controller. During processing, compensation is performed by interpolation through table lookup.

[0022] However, when the actual movement trajectory of the robot deviates from the calibrated trajectory due to load changes, temperature drift, servo lag, or external disturbances, the pre-stored calibration table cannot reflect the true pose changes, leading to focus shift. For high-speed continuous machining requirements, the lag of this static calibration method is more pronounced, resulting in larger calibration errors.

[0023] Based on this, the main solution of the embodiments of this application is: When the current processing point completes processing, obtain the displacement of the robot relative to the calibration reference point and the deflection angle of the galvanometer; The focal offset is calculated based on the coupling coefficient, displacement, and deflection angle between the pre-calibrated manipulator displacement and the galvanometer deflection. The actuator is controlled to perform focus compensation based on the focus offset in order to correct the focus position of the next processing point.

[0024] In the focus compensation method of the coordinate system provided in this application, if the current processing point is completed, the displacement of the robot relative to the calibration reference point and the deflection angle of the galvanometer are obtained. Then, based on the pre-calibrated coupling coefficient between the robot displacement and the galvanometer deflection, the displacement is decomposed into a first component along the optical axis and a second component perpendicular to the optical axis. The second component is used as the reference focus offset, and the coupled focus offset is calculated based on the coupling coefficient, the first component, and the tangent of the deflection angle. The reference focus offset and the coupled focus offset are then superimposed to obtain the total focus offset. Finally, according to the system hardware configuration, the appropriate compensation mode is selected, and focus compensation is performed through the galvanometer focusing module and / or the robot's Z-axis fine-tuning module to correct the focus position of the next processing point. This achieves real-time dynamic compensation of the focus during the continuous movement of the robot, solving the technical problem that static calibration tables cannot reflect dynamic pose changes leading to focus shift, and improving the focus control accuracy and processing quality consistency of laser precision machining.

[0025] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a computer, server, and / or laser processing equipment, or an electronic device capable of performing the above functions. For ease of description, the executing device of the coordinate system focus compensation method will be uniformly described as a focus compensation device, and the following embodiments will be described accordingly.

[0026] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0027] First Embodiment This embodiment provides a focus compensation method for a coordinate system, referring to... Figure 1 The flowchart of the first embodiment of the focus compensation method for the coordinate system shown is illustrated. The method includes steps S10 to S30: Step S10: Obtain the displacement of the robot relative to the calibration reference point and the deflection angle of the galvanometer when the current processing point completes processing; The displacement of the robotic arm relative to the calibration reference point refers to the three-dimensional position change vector of the robotic arm's end effector relative to the calibration reference point at the current moment. The galvanometer deflection angle refers to the angle by which the X-axis and Y-axis galvanometers inside the galvanometer rotate around their respective axes of rotation. In laser processing equipment, the deflection of the laser beam in the X and Y directions is controlled by adjusting the galvanometer deflection angle.

[0028] The calibration reference point is the pose reference point determined when the robot arm is in the calibration pose and the galvanometer is in a zero-deflection state. This allows the calibration reference point to be used as a reference point during subsequent processing to determine the pose changes of the robot arm and galvanometer relative to their initial state. This calibration reference point can be determined and recorded manually or automatically during the equipment debugging or calibration phase.

[0029] During the processing of a workpiece by a laser processing equipment, processing can be performed point-by-point according to preset processing points. The focus compensation device determines whether the laser processing equipment has completed the processing action at the current processing point by acquiring the equipment's operating parameters. Understandably, the acquired operating parameters may include an indication signal indicating the completion of the laser processing action, the moment when energy output stopped during the processing of the current processing point, etc.

[0030] If it is determined that the laser processing equipment has completed the processing procedure at the current processing point, the robot arm and galvanometer will remain in the final pose after the processing at the current processing point is completed. Therefore, the focus compensation device can trigger the parameter acquisition process at this time.

[0031] Understandably, since the robot arm is in real-time motion during continuous processing and its posture changes constantly over time, it is necessary to obtain the current displacement of the robot arm and the current deflection angle of the galvanometer in real time during each control cycle in order to calculate the focus offset later.

[0032] In this embodiment, the displacement of the robot relative to the calibration reference point is obtained by an absolute encoder, and the actual deflection angle of the galvanometer is collected by the position sensor built into the galvanometer.

[0033] Specifically, upon completion of processing at the current processing point, the main control unit simultaneously sends a data latch command to the robot's motion control unit and the galvanometer drive unit to lock the motion parameters at the current moment. Next, the data acquisition module reads the angle values ​​of each joint at the latched moment from the absolute encoders of each joint of the robot. Then, based on the read joint angle values, the real-time pose of the robot's end effector within the current control cycle is calculated using the robot's forward kinematics algorithm. Finally, the current real-time pose is subtracted from the pre-stored calibration reference pose to obtain the displacement ΔL(t) of the robot relative to the calibration reference point.

[0034] Similarly, after the galvanometer drive unit receives the data latching command from the main control unit, the data acquisition module reads the actual deflection angles θ_ of the X-axis and Y-axis galvanometers at the latching moment from the position sensors built into the galvanometer. x (t) and θ_ y (t). Then, the read X-axis deflection angle and Y-axis deflection angle are used as the current deflection angle of the galvanometer, and the deflection angle is calculated according to Formula 1: (Formula 1) In this embodiment, by acquiring the displacement of the robot arm and the deflection angle of the galvanometer in real time during each control cycle, an accurate data basis is provided for calculating the focus offset in step S20. This enables the subsequent dynamic calculation of the actual focus offset at the current moment by combining the pre-calibrated coupling coefficient. This solves the technical problem that the existing static calibration table cannot adapt to the dynamic trajectory deviation of the robot arm, and realizes the real-time online correction of the focus position during the continuous movement of the robot arm, so that the laser focus remains within the target focal depth range on the workpiece surface without stopping the robot arm.

[0035] The above is only a specific implementation of step S10 provided in this embodiment. This embodiment does not specifically limit the specific implementation of step S10.

[0036] Step S20: Calculate the focal offset based on the pre-calibrated coupling coefficient between the robot arm displacement and the galvanometer deflection, the displacement amount, and the deflection angle. The coupling coefficient is a comprehensive coefficient related to the optical system structure and the kinematic parameters of the manipulator. It characterizes the coupling mapping relationship between the manipulator's displacement and the galvanometer deflection along the optical axis. When the manipulator displaces perpendicular to the optical axis, an additional focal offset will be generated along the optical axis due to the galvanometer deflection. This offset satisfies... Where n is the coupling coefficient. The physical meaning of this coupling coefficient is: the focal offset coupling factor generated in the optical axis direction after the lateral displacement of the robot arm is amplified by the deflection optical path of the galvanometer. This coupling coefficient can be a static coupling coefficient or a segmented coupling coefficient. When the coupling coefficient is static, it is assumed that the focal offset coupling factor in the entire working path is a fixed value; while when the coupling coefficient is segmented, the corresponding segmented coupling coefficient needs to be dynamically selected based on the actual processing section of the robot arm.

[0037] Focus offset refers to the deviation of the actual position of the laser focus from the reference focus position along the optical axis during laser processing.

[0038] Understandably, since the displacement of the robotic arm includes components along the optical axis and components perpendicular to the optical axis, the displacement component along the optical axis directly causes the focal point to shift, while the component perpendicular to the optical axis indirectly causes the focal point to shift through coupling with the galvanometer deflection. Therefore, it is necessary to decompose the robotic arm displacement into two components and process them separately.

[0039] In this embodiment, step S20 may include steps S21 to S24: Step S21: Decompose the displacement into a first component along the optical axis and a second component perpendicular to the optical axis. First, obtain the first component along the optical axis within the current control cycle. The first component along the optical axis can be obtained through a homogeneous transformation matrix from the galvanometer coordinate system to the optical axis coordinate system. To determine this: Extract the rotation matrix component corresponding to the Z-axis direction from the homogeneous transformation matrix, i.e., the first three elements of the third column of the matrix. This vector represents the spatial direction of the laser beam in the galvanometer coordinate system under the current galvanometer deflection state. Project the robot's displacement ΔL(t) onto the unit vector along this optical axis direction. By calculating the dot product of the displacement and the unit vector along the optical axis direction, the first component ΔL_ along the optical axis direction is obtained. z (t); the second component ΔL_ perpendicular to the optical axis xy (t) is obtained by calculation using the Pythagorean theorem, specifically: The first vector along the optical axis is calculated using the following formula: ,in Let φ(t) be the unit vector along the optical axis, and let φ(t) be the angle between the displacement vector and the optical axis.

[0040] The second component ΔL_ perpendicular to the optical axis xy (t) is then calculated using Formula 2: (Formula 2) Wherein, ΔL_ z (t) represents the first component of the manipulator along the optical axis, ΔL_ xy (t) represents the second component of the robot arm in the direction perpendicular to the optical axis.

[0041] Step S22: Determine the second component as the reference focus offset; The second component ΔL_ obtained in step S21, perpendicular to the optical axis, is... xy (t) is determined as the reference focus offset ΔZ_ base (t), that is: Its physical meaning is: the distance that the end effector of the robot moves in the direction perpendicular to the optical axis is the reference offset of the laser focus in the direction perpendicular to the optical axis.

[0042] Step S23: Calculate the coupling focus offset based on the coupling coefficient, the second component, and the deflection angle; Based on the pre-calibrated coupling coefficient n, the second component ΔL_ perpendicular to the optical axis xy (t) and the deflection angle of the galvanometer are combined to form the deflection angle. Then, the tangent of the deflection angle is determined, followed by the calculation of the coupling coefficient n, the tangent tanθ(t), and the second component ΔL_. xy The product of (t) and (t) gives the coupling focus offset, and its formula is: ; Step S24: Determine the sum between the reference focus offset and the coupled focus offset, and use it as the focus offset; Add the reference focus offset obtained in step S22 and the coupling focus offset obtained in step S23 to obtain the total focus offset, i.e.: .

[0043] In this embodiment, by decomposing the displacement into two components along the optical axis and perpendicular to the optical axis, and calculating their respective focal offsets, the coupling relationship between the robot's displacement and the galvanometer deflection can be accurately reflected, thereby improving the calculation accuracy of the focal offset.

[0044] Furthermore, in an embodiment considering the effect of thermal drift, the focus offset can also be obtained by combining the thermal drift compensation value with the reference focus offset and the coupled focus offset. Therefore, after step S23, the following may also be included: Step S25: Determine the thermal drift compensation value based on the temperature data collected by the temperature sensor; Thermal drift compensation value ΔZ_ thermal (t) can be determined by the thermal drift coefficient k_ calibrated in advance through experiments. T Calculation of the product with the change in temperature: , where T(t) is the temperature value collected in real time by the temperature sensor, and T0 is the reference temperature during calibration.

[0045] Step S26: Determine the sum of the reference focus offset, the coupled focus offset, and the thermal drift compensation value as the focus offset; Right now .

[0046] In this embodiment, a thermal drift compensation term is introduced, which can eliminate the influence of ambient temperature changes on the focal position and further improve the accuracy of focal compensation.

[0047] To aid in understanding the specific implementation process of this embodiment, please refer to... Figure 2 The diagram below shows a simplified flowchart of the focus offset calculation method in the coordinate system shown. Specifically: First, the displacement is decomposed into a first component along the optical axis and a second component perpendicular to the optical axis. Then, the second component is determined as the reference focus offset; simultaneously, the coupled focus offset is calculated based on the coupling coefficient n, the second component, and the deflection angle. Next, the reference offset and the coupled offset are added together. Based on this, it is determined whether thermal drift should be considered: if not, the sum is directly used as the total focus offset and output; if so, a thermal drift compensation value is determined based on temperature sensor data, and this thermal drift compensation value is superimposed on the total focus offset before output; finally, the total focus offset is output.

[0048] For example, in the scenario of QR code marking on automotive engine cylinder heads, the cylinder head surface is a complex free-form surface with a radius of curvature varying from 50mm to 500mm, requiring the focus stability to be controlled within ±10μm. The system has completed the coupling coefficient calibration, and the X-direction coupling coefficient n_ x =0.82, Y-direction coupling coefficient n_ y =0.85. During the processing, the controller executes step S20 within a 250μs control cycle: decomposes the robot's current displacement ΔL(t) into the first component ΔL_ along the optical axis. z (t) and the second component ΔL_ perpendicular to the optical axis xy (t); Based on the current working distance, query the segmented coupling coefficient lookup table to obtain the coupling coefficient n of the current segment; according to ΔZ_ base =ΔL_ z (t) Calculate the reference focus offset according to ΔZ_ couple =n·ΔL_ xy The coupling focus offset is calculated by tanθ(t) and the two are added together to obtain the total focus offset ΔZ_. total (t).

[0049] Step S30: Control the actuator to perform focus compensation based on the focus offset to correct the focus position of the next processing point; An actuator is a specific hardware device used to adjust the focal position. Depending on the system configuration, the actuator may include a focusing module for a galvanometer, a Z-axis fine-tuning module for a robotic arm, or a combination of the two. Optionally, the actuator may also be other control modules used to control the robotic arm and / or the galvanometer.

[0050] It is understandable that the focus offset calculated by step S20 is the focus offset when the current processing point is completed. This offset reflects the influence of the robot and galvanometer on the focus position when in the current pose. In order to ensure the accuracy of the focus position at the next processing point, the focus position needs to be corrected in advance before the next control cycle arrives based on the currently calculated focus offset.

[0051] The actuator may include the focusing module of the galvanometer and / or the Z-axis fine-tuning module of the robot.

[0052] Therefore, as an optional implementation, when the actuator is the focusing module of the galvanometer, the controller inverts the focus offset and outputs it directly to the driver of the galvanometer focusing module. The voice coil motor then drives the lens group to move the corresponding displacement along the optical axis. The compensation command is... , where λ is the allocation coefficient and λ=1. Since the galvanometer focusing module has a response bandwidth of up to 1kHz, it can respond quickly in each control cycle. Therefore, this mode is suitable for high-frequency, small-amplitude compensation scenarios.

[0053] As another optional implementation, when the actuator is a Z-axis fine-tuning module, the controller converts the required focus compensation amount into a fine-tuning command for the robot end effector along the Z-axis direction through inverse kinematics calculation. The allocation coefficient λ = 0. This instruction is sent to the robot controller via the bus, and the robot servo system executes a small Z-axis displacement. This mode is suitable for low-cost systems with galvanometers that do not have a dynamic focusing module, but because the response frequency of the robot servo system is usually below 50Hz, this mode is suitable for scenarios requiring large-amplitude compensation at low frequencies.

[0054] Furthermore, when the actuators are the focusing module of the galvanometer and the Z-axis fine-tuning module of the robot, the controller sets an allocation coefficient λ (0 < λ < 1) to proportionally distribute the focus compensation amount to the two actuators: the galvanometer focusing module receives... The robot arm's Z-axis fine-tuning module receives... By properly configuring λ, the galvanometer focusing module can handle scenarios requiring high-frequency, small-amplitude compensation, while the robot's Z-axis can handle scenarios requiring low-frequency, large-amplitude compensation. This allows for the full utilization of the advantages of each actuator and prevents any single actuator from exceeding its response bandwidth or travel range.

[0055] In this embodiment, step S30 includes steps S31 to S34: Step S31: Determine the first focusing ratio of the focusing module and the second focusing ratio of the Z-axis fine-tuning module; The aforementioned first and second focusing ratios are pre-set allocation coefficients used to distribute the total focus compensation amount to different actuators. The first focusing ratio is denoted as λ (0 ≤ λ ≤ 1), and the second focusing ratio is denoted as (1-λ). When λ = 1, it indicates that all focus compensation is handled by the galvanometer focusing module; when λ = 0, it indicates that all focus compensation is handled by the robot's Z-axis fine-tuning module; when 0 < λ < 1, it indicates that the focus compensation amount is proportionally distributed to the two actuators.

[0056] Step S32: Determine the product of the first focusing ratio and the focus offset as the first adjustment value of the focusing module; The first adjustment value of the focusing module is calculated using the following formula: The negative sign indicates that the adjustment direction is opposite to the focus offset direction. The first adjustment value is ΔZ_ DFM (t) represents the amount of compensation displacement that the focusing module needs to perform.

[0057] Step S33: Determine the product of the second focusing ratio and the focus offset as the second adjustment value of the Z-axis fine-tuning module; Calculate the second adjustment value of the Z-axis fine-tuning module according to Formula 3: (Formula 3) The negative sign indicates that the adjustment direction is opposite to the focus offset direction. Second adjustment value ΔZ_ robot (t) represents the amount of compensation displacement that the Z-axis fine-tuning module needs to perform.

[0058] Step S34: Control the focusing module to perform focus compensation based on the first adjustment value, and / or control the Z-axis fine-tuning module to perform focus compensation based on the second adjustment value; The controller will use the first adjustment value ΔZ_ obtained in step S32 DFM (t) and / or the second adjustment value ΔZ_ obtained in step S33 robot (t) The signals are sent to the corresponding actuators via the bus or analog channel, and the respective actuators drive the corresponding mechanical parts to move and adjust the focus position.

[0059] In one specific implementation, the voice coil motor driver of the galvanometer focusing module receives an analog voltage command, which, after power amplification, drives the voice coil motor mover to move the lens assembly along the optical axis. A position sensor provides real-time feedback on the actual displacement of the lens assembly, forming a closed-loop control to ensure the accuracy of displacement compensation.

[0060] In another specific implementation, the robot's Z-axis fine-tuning module receives position correction commands via the EtherCAT bus (EtherCAT is a high-performance real-time Ethernet communication protocol for industrial automation, which is an "ultra-high-speed communication network" connecting the controller, robot, and galvanometer). The robot controller superimposes these commands onto the original Z-axis motion commands, and the servo driver and motor execute a small Z-axis displacement.

[0061] For example, in the scenario of welding a titanium alloy mid-frame for a mobile phone, the allocation coefficient λ is set to 0.7, meaning that the galvanometer focusing module undertakes 70% of the focus compensation, and the robot's Z-axis fine-tuning module undertakes 30% of the focus compensation. High-frequency components are compensated by the galvanometer focusing module, while low-frequency components are compensated by the robot's Z-axis. In the scenario of laser hardening of large molds, since the galvanometer has no dynamic focusing module, the allocation coefficient λ is set to 0, and the compensation is entirely performed by the robot's Z-axis in conjunction with the variable-focus laser head.

[0062] To aid in understanding the specific implementation process of this embodiment, please refer to... Figure 3 The focus compensation method for the coordinate system shown provides a simplified flowchart of the focus compensation process, specifically: First, the compensation mode is determined. Based on the system hardware configuration and processing requirements, one of mode A, mode B, or mode C is selected: mode A is dynamic focusing compensation of the galvanometer, mode B is Z-axis fine-tuning compensation of the robot arm, and mode C is composite compensation. Further spectrum separation is then performed. After determining the compensation mode, the compensation command is executed and sent to the actuator driver. Based on this, it is determined whether closed-loop correction should be enabled: if not, compensation is complete, and the next control cycle begins; if so, residual error is measured in real time using sensors, and the residual error is fed back before the compensation command is re-executed, forming closed-loop control until compensation is complete, and the next control cycle begins.

[0063] In this embodiment, multi-mode adaptive compensation is used to enable the galvanometer focusing module to be responsible for high-frequency small-amplitude compensation and the robot arm Z-axis to be responsible for low-frequency large-amplitude compensation, which takes into account both high-frequency response and large-stroke compensation. This improves the stability and compensation accuracy of the system while ensuring that each actuator does not exceed the limits.

[0064] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment can be referred to the above description, and will not be repeated hereafter. Furthermore, before step S10, the focus compensation method for the coordinate system further includes steps S01 to S04: Step S01: Obtain the calibration data combination of multiple sets of robot arm calibration displacement and galvanometer calibration deflection angle contained in the calibration plate; A calibration plate is a specialized fixture used for calibrating coupling coefficients. It is typically made of a flat metal or ceramic plate, with a precision-machined surface to ensure flatness. The material of the calibration plate should be similar to or the same as the material of the actual workpiece to minimize the impact of material property differences on the calibration results. Calibration displacement refers to the preset displacement value of the robot arm's movement perpendicular to the optical axis during the calibration phase; calibration deflection angle refers to the preset angle value of the galvanometer's deflection during the calibration phase. Each set of calibration data is formed by pairing a calibration displacement value with a calibration deflection angle value, used to establish the correspondence between the robot arm's pose, galvanometer state, and focal offset. By acquiring multiple different sets of calibration data, sufficient sample data is provided for subsequent least-squares fitting of the coupling coefficients.

[0065] Specifically, the calibration plate is horizontally fixed on the worktable, and multiple calibration points are preset on the surface of the calibration plate to form a grid-like layout. The spacing between each calibration point should be evenly distributed to ensure that the calibration data can cover the displacement and deflection range of the entire processing area. At each calibration point, the robot arm is controlled to generate multiple calibration displacements ΔL_i in a plane perpendicular to the optical axis. For each calibration displacement point, the galvanometer is controlled to deflect multiple different calibration deflection angles θ_j in the X and Y directions. Each calibration displacement and each deflection angle are combined to form multiple sets of calibration data combinations (ΔL_i, θ_j). Each set of calibration data combinations (ΔL_i, θ_j) and the corresponding calibration point position information are recorded and stored in the controller's storage device.

[0066] It should be noted that before this step, it is necessary to construct the robot's base coordinate system, galvanometer coordinate system, and laser optical axis coordinate system, and calibrate the homogeneous transformation matrix from the robot's end flange to the galvanometer coordinate system based on the hand-eye calibration algorithm. And the transformation matrix from the galvanometer coordinate system to the laser optical axis coordinate system, which varies with the galvanometer deflection angle. This achieves the unification of the three coordinate systems. Among them, Calibrated using the standard ball method The transformation matrix is ​​calibrated using a telecentric lens and a calibration board. After calibration, the transformation matrix is ​​stored in the controller for subsequent processing.

[0067] Step S02: Calculate the actual focus offset corresponding to each set of calibration data; The actual focus offset refers to the deviation of the actual position of the laser focus relative to the reference focus position (ΔL=0, θ=0°) in the optical axis direction, obtained by measurement for each set of input calibration parameters (ΔL_i, θ_j) during the calibration process. This measured focus offset is used as the observation sample output of the least squares fitting coupling coefficient, and the model to be fitted uses (ΔL_i, θ_j) as input to predict the focus offset.

[0068] Specifically, first, the robot arm is controlled to return to the calibration reference point and the galvanometer returns to the zero deflection state. At this time, the position of the laser focus on the calibration plate is defined as the reference focus position. The laser confocal displacement sensor is used to measure the distance value of the focus relative to the sensor reference point at this time, which is used as the reference distance value d0.

[0069] Then, for each set of calibration data (ΔL_i, θ_j) generated in step S01, the controller sequentially controls the robot arm to move to the corresponding calibration displacement ΔL_i, while simultaneously controlling the galvanometer to deflect to the corresponding calibration deflection angle θ_j. The distance d_ij of the current focal point relative to the sensor is measured using a laser confocal displacement sensor. Subtracting the reference distance d0 from the current distance d_ij yields the actual focal offset corresponding to that set of calibration data. .in The value is a signed number, with positive and negative indicating the direction of focus offset.

[0070] Repeat the above steps until all calibration data combinations have been measured, and record the actual focus offset obtained from each set of measurements. The calibration displacement ΔL_i and calibration deflection angle θ_j are recorded one-to-one to form a complete calibration dataset and stored in the controller.

[0071] Step S03: Based on the least squares method, fit the actual focal offset, calibration displacement and calibration deflection angle of each group to obtain the calibration coupling coefficient between the pre-calibrated manipulator displacement and the galvanometer deflection. Least squares is a mathematical optimization technique that finds the best function match for data by minimizing the sum of squared errors.

[0072] In this embodiment, the least squares method is used to fit the calibration data, namely the calibration displacement ΔL_i, the calibration deflection angle θ_j, and the actual focus offset. To determine the coupling coefficient n that minimizes the overall fitting error of all calibration data points.

[0073] Based on the principle of least squares, we construct the sum of squared errors function, namely: , By differentiating S(n) with respect to n and setting the derivative to zero, the fitting formula for the coupling coefficient n is obtained: , Substituting all the calibration data measured in step S02 into the above formula, the coupling coefficient n can be obtained and stored in the controller's non-volatile memory.

[0074] For example, in the scenario of QR code marking on the cylinder head of an automobile engine, the calibration data in the X and Y directions are substituted into the fitting formula to obtain the coupling coefficient n_ in the X direction. x =0.82, Y-direction coupling coefficient n_ y =0.85.

[0075] Step S04: Use the calibrated coupling coefficient as the coupling coefficient; It should be noted that the calibration coupling coefficient n obtained by least squares fitting in step S03 reflects the coupling mapping relationship between the robot displacement and the galvanometer deflection in the optical axis direction. This coefficient is obtained under calibration conditions and is used to characterize the coupling characteristics under the calibration conditions.

[0076] Specifically, the calibration coupling coefficient n calculated in step S03 is used as the coupling coefficient required to calculate the focal offset in the subsequent processing. It is stored in the controller's non-volatile memory so that when the subsequent processing point is completed, the focal offset can be calculated based on the displacement of the robot relative to the calibration reference point and the deflection angle of the galvanometer.

[0077] In this embodiment, the coupling coefficient is accurately calibrated through a complete technical chain of coordinate system calibration, multi-condition calibration data acquisition, precise measurement, and optimal fitting. This provides an accurate, reliable, and comprehensive parameter basis for the calculation of dynamic focus offset in the subsequent implementation step S20, thereby ensuring the accuracy and reliability of the entire dynamic focus compensation method.

[0078] Based on the second embodiment, in the third embodiment, the same or similar content as in the above embodiment can be referred to the above description, and will not be repeated hereafter. Furthermore, after step S03, steps S05-S07 are also included: Step S05: Determine each processing section based on the robot's movement direction and / or working distance; Specifically, the criteria for dividing the processing sections are determined based on the actual processing scenario and accuracy requirements. The criteria for division include at least one of the following three methods: In one alternative implementation, the division is based on the direction of motion. Since the optical characteristics of the optical system may differ in the X and Y directions, the coupling coefficient n may also differ in the X and Y directions; therefore, the processing section is divided according to the direction of motion.

[0079] In another alternative implementation, the processing section is divided according to the working distance. Since the magnification of the optical system varies with the working distance, the coupling coefficient n may be different at different working distances. Therefore, the processing section is divided according to the working distance.

[0080] Furthermore, the process is divided according to the combination of motion direction and working distance. Considering both motion direction and working distance, a two-dimensional segmentation is performed, dividing the processing space into multiple combined segments such as "X-direction + distance segment" and "Y-direction + distance segment," and assigning corresponding segment coupling coefficients to each.

[0081] Step S06: Calculate the segmented coupling coefficient based on the corresponding calibration coupling coefficient within each processing section; Specifically, within each processing section, the calibration data combination for that section is obtained according to steps S01 to S03, the corresponding actual focus offset is measured, and the segmented coupling coefficient n_ corresponding to that section is obtained by least squares fitting. k Traverse all processing sections to obtain the segmented coupling coefficients n1, n2, ..., n for each section. mThis forms a segmented coupling coefficient lookup table, which is stored in the controller.

[0082] Step S07: Use the segmented coupling coefficient as the coupling coefficient; Specifically, during real-time processing, the controller, based on the segmented coupling coefficient lookup table established in step S06, retrieves the segmented coupling coefficient n_ determined in step S06. k The coupling coefficient n(t) is used as the current time step.

[0083] Understandably, since the robotic arm will traverse different processing sections during continuous processing, the segment coupling coefficients corresponding to different sections may be different. Therefore, it is necessary to dynamically select the corresponding segment coupling coefficient according to the current section in each control cycle to ensure the accuracy of the focus offset calculation.

[0084] Specifically, when the robotic arm is currently near the boundary between two adjacent segments, to avoid abrupt changes in the compensation command caused by sudden changes in the coupling coefficient, a linear interpolation method is used to calculate the transition coupling coefficient:

[0085] Where n_ a and n_ b Here, w1 and w2 are the segmented coupling coefficients for two adjacent segments, respectively. w1 and w2 are weighting coefficients determined based on the distance ratio of the current parameters on both sides of the boundary, satisfying w1 + w2 = 1. This interpolation process avoids abrupt changes in the coupling coefficients when the robot moves near the segment boundaries, ensuring the smoothness of the compensation commands.

[0086] In this embodiment, segmented calibration enables the coupling coefficient within each segment to more accurately reflect the actual optical characteristics of that segment, thereby improving the accuracy of the coupling coefficient and thus enhancing the accuracy of the focus offset calculation.

[0087] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the focus compensation method of the coordinate system of this application. Any simple transformations based on this technical concept are within the protection scope of this application.

[0088] This application provides a focus compensation device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform the focus compensation method of the coordinate system in the first embodiment described above.

[0089] Furthermore, the focus compensation device may include a robotic arm motion unit, a galvanometer scanning unit, a laser emission unit, a unified coordinate system calibration module, a dynamic compensation calculation unit, an execution compensation unit, and a sensor feedback unit.

[0090] The robotic arm motion unit can take the form of a six-axis industrial robot, SCARA, or linear module, etc., to carry the laser processing head or workpiece for large-stroke movement, and has real-time pose feedback function, providing pose data at the current moment through encoder or servo driver.

[0091] The galvanometer scanning unit can adopt a dual-axis (XY) or tri-axis (XY+Z dynamic focusing) galvanometer system, which includes a galvanometer motor, a reflector and a position sensor, to control the laser beam to deflect and scan within a local range and to provide real-time feedback on the deflection angle of the galvanometer.

[0092] The laser emitting unit is used to provide the processing light source, and can be a laser source such as a fiber laser, CO2 laser or ultraviolet laser.

[0093] The unified coordinate system calibration module is used to establish the homogeneous transformation matrix between the robot's base coordinate system {B}, the galvanometer coordinate system {G}, and the laser optical axis coordinate system {L}, thereby achieving the unification of the three coordinate systems.

[0094] The dynamic compensation calculation unit can be in the form of hardware such as embedded controller, industrial computer or FPGA, to run the focus offset compensation algorithm and calculate the focus offset caused by the coupling of the robot displacement and the galvanometer deflection in real time.

[0095] The execution compensation unit, or execution mechanism, can be a dynamic focusing module, such as a Z-axis voice coil motor, a piezoelectric ceramic driver, or a robot Z-axis fine-tuning module, used to adjust the laser focus position according to the focus offset.

[0096] The sensing feedback unit is an optional module and can use sensing elements such as laser triangulation sensors, confocal sensors or vision cameras to measure the actual focal position in real time and achieve closed-loop correction.

[0097] The following is for reference. Figure 4 The diagram illustrates a structural schematic suitable for implementing the focus compensation device in the embodiments of this application. The focus compensation device in the embodiments of this application may include, but is not limited to, terminal devices such as computers, servers, and / or laser processing equipment, or electronic devices capable of performing the aforementioned functions. Figure 4 The focus compensation device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0098] like Figure 4As shown, the focus compensation device may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The random access memory 1004 also stores various programs and data required for the operation of the focus compensation device. The processing unit 1001, the read-only memory 1002, and the random access memory 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the input / output interface 1006: input devices 1007 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the focus compensation device to communicate wirelessly or wiredly with other devices to exchange data. Although focus compensation devices with various systems are shown in the figures, it should be understood that it is not required to implement or possess all the systems shown. More or fewer systems can be implemented alternatively.

[0099] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from read-only memory 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0100] The focus compensation device provided in this application employs the focus compensation method of the coordinate system in the above embodiments. This solves the technical problem that when the actual movement trajectory of the robot arm deviates from the calibrated trajectory due to load changes, temperature drift, servo lag, or external disturbances, the pre-stored calibration table cannot reflect the true pose changes, leading to focus offset. Compared with the prior art, the beneficial effects of the focus compensation device provided in this application are the same as those of the focus compensation method of the coordinate system provided in the above embodiments, and other technical features of this focus compensation device are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0101] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0102] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0103] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory, read-only memory, erasable programmable read-only memory (EPROM, or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, radio frequency (RF), etc., or any suitable combination thereof.

[0104] The aforementioned computer-readable storage medium may be included in the focus compensation device; or it may exist independently and not assembled into the focus compensation device.

[0105] The aforementioned computer-readable storage medium carries one or more programs, which, when executed by the focus compensation device, cause the focus compensation device to perform the steps of the focus compensation method for the coordinate system described above: Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0106] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation that may be implemented in systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0107] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0108] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the focus compensation method of the above-described coordinate system. This solves the technical problem that when the actual motion trajectory of the robot arm deviates from the calibrated trajectory due to load changes, temperature drift, servo lag, or external disturbances, the pre-stored calibration table cannot reflect the true pose changes, leading to focus shift. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the focus compensation method of the coordinate system provided in the above embodiments, and will not be elaborated upon here.

[0109] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for focus compensation in a coordinate system, characterized in that, The focus compensation method for the coordinate system includes: When the current processing point completes processing, obtain the displacement of the robot relative to the calibration reference point and the deflection angle of the galvanometer; Based on the pre-calibrated coupling coefficient between the robot arm displacement and the galvanometer deflection, the focal offset is calculated using the displacement and the deflection angle. The actuator is controlled to perform focus compensation based on the focus offset to correct the focus position of the next processing point; The step of calculating the focal offset based on the pre-calibrated coupling coefficient between the robot arm displacement and the galvanometer deflection, the displacement amount, and the deflection angle includes: The displacement is decomposed into a first component along the optical axis and a second component perpendicular to the optical axis. The second component is determined as the reference focus offset; The coupling focus offset is calculated based on the coupling coefficient, the second component, and the deflection angle. The sum of the reference focus offset and the coupled focus offset is determined as the focus offset; The step of calculating the coupling focus offset based on the coupling coefficient, the second component, and the deflection angle includes: The deflection angles are combined into a deflection angle, and the tangent of the deflection angle is determined. The coupling focus offset is obtained by calculating the product of the coupling coefficient, the tangent value, and the second component. Before the step of obtaining the displacement of the robot arm relative to the calibration reference point and the deflection angle of the galvanometer when the current processing point completes processing, the focus compensation method of the coordinate system further includes: Obtain the calibration data combination of multiple sets of manipulator calibration displacement and galvanometer calibration deflection angle contained in the calibration plate; Calculate the actual focus offset corresponding to each set of calibration data; Based on the least squares method, the actual focus offset, the calibration displacement, and the calibration deflection angle of each group are fitted, and the calibration coupling coefficient between the pre-calibrated manipulator displacement and the galvanometer deflection is calculated. The calibration coupling coefficient is used as the coupling coefficient; The calculation of the actual focus offset corresponding to each set of calibration data includes: When the robotic arm returns to the calibration reference point and the galvanometer is in a zero-deflection state, the reference distance value is obtained; Measure the current distance value of each set of calibration data; Subtracting the reference distance value from the current distance value yields the actual focus offset corresponding to each set of calibration data.

2. The coordinate system focus compensation method as described in claim 1, characterized in that, After the step of calculating the coupling focus offset based on the coupling coefficient, the second component, and the deflection angle, the focus compensation method for the coordinate system further includes: The thermal drift compensation value is determined based on the temperature data collected by the temperature sensor. The sum of the reference focus offset, the coupled focus offset, and the thermal drift compensation value is determined as the focus offset.

3. The coordinate system focus compensation method as described in claim 1, characterized in that, After the step of obtaining the coupling coefficient between the pre-calibrated manipulator displacement and the galvanometer deflection by fitting each group of actual focus offsets, calibration displacements, and calibration deflection angles using the least squares method, the focus compensation method for the coordinate system further includes: Each processing section is determined based on the movement direction and / or working distance of the robotic arm; Based on the calibration coupling coefficients corresponding to each processing section, the segmented coupling coefficients are calculated. The segmented coupling coefficient is used as the coupling coefficient.

4. The coordinate system focus compensation method as described in claim 1, characterized in that, Before the step of obtaining the calibration data combination of multiple sets of manipulator calibration displacements and galvanometer calibration deflection angles contained in the calibration plate, the focus compensation method of the coordinate system further includes: During the calibration phase, the robot's base coordinate system, galvanometer coordinate system, and laser optical axis coordinate system are constructed. Based on the hand-eye calibration algorithm, a homogeneous transformation matrix from the end flange of the robotic arm to the galvanometer coordinate system is constructed, as well as a transformation matrix from the galvanometer coordinate system to the laser optical axis coordinate system that varies with the galvanometer deflection angle.

5. The coordinate system focus compensation method as described in claim 1, characterized in that, The actuator includes the focusing module of the galvanometer and the Z-axis fine-tuning module of the manipulator; The step of controlling the actuator to perform focus compensation based on the focus offset to correct the focus position of the next processing point includes: Determine the first focusing ratio of the focusing module and the second focusing ratio of the Z-axis fine-tuning module; The product of the first focusing ratio and the focus offset is determined as the first adjustment value of the focusing module; The product of the second focusing ratio and the focus offset is determined as the second adjustment value of the Z-axis fine-tuning module; The focusing module is controlled to perform focus compensation based on the first adjustment value, and / or the Z-axis fine-tuning module is controlled to perform focus compensation based on the second adjustment value.

6. A focus compensation device, characterized in that, The focus compensation device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the focus compensation method for the coordinate system as described in any one of claims 1 to 5.

7. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the focus compensation method for the coordinate system as described in any one of claims 1 to 5.

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