A galvanometer system correction method and device

Abstract

The application provides a galvanometer system correction method and device, the method comprises the following steps: S1, an error analysis model of the galvanometer system is established; S2, a correction accuracy target is determined according to the error analysis model; S3, an iterative correction process is executed based on the correction accuracy target, each iteration comprises: an error value between an actual output position of the galvanometer system and a theoretical target position is obtained, and the galvanometer system control parameters are compensated and corrected according to the error value; S4, the iterative correction process is repeatedly executed until the error value meets a preset termination condition. The application establishes the error analysis model of the galvanometer system to clearly define the theoretical upper limit of each error source, thereby performing hardware selection and accuracy budget allocation, ensuring that the errors of each link are within a controllable range, and guaranteeing the realizability of the final accuracy from the source; and the iterative correction is adopted instead of one-time full compensation, which can quickly converge the accuracy and avoid oscillation divergence caused by over-compensation, thereby significantly improving the correction stability and convergence reliability.

Description

Technical Field

[0001] This invention belongs to the field of optical equipment calibration technology, specifically relating to a galvanometer system calibration method and apparatus. Background Technology

[0002] As the core scanning component of laser processing equipment, the positioning accuracy of the galvanometer system directly determines the precision and quality of laser processing. Existing galvanometer calibration technologies mainly include the BOX calibration method and the two-dimensional calibration method. The BOX calibration method uses mechanical positioning blocks for calibration, and relying on these blocks, the calibration accuracy can only reach ±0.5mm, which cannot meet the requirements of precision machining. The two-dimensional calibration method uses two-dimensional measuring instruments for calibration, and although the accuracy can reach about ±0.07mm, it is complex to operate, takes more than 1 hour to calibrate, requires professional personnel, and is costly.

[0003] Existing technologies generally suffer from four major pain points: First, insufficient accuracy, unable to achieve a stable accuracy of ±0.01mm within a 200mm×200mm area, with particularly noticeable accuracy decay in edge areas; second, poor stability, easily caused by temperature changes and environmental vibrations leading to accuracy drift, and severe accuracy decay after long-term operation, requiring frequent recalibration; third, low calibration efficiency, with cumbersome and time-consuming processes affecting equipment utilization; and fourth, high operational threshold, relying on professional personnel, resulting in high labor and training costs. Summary of the Invention

[0004] The purpose of this invention is to provide a galvanometer system calibration method that can at least solve some of the defects existing in the prior art.

[0005] Therefore, the present invention adopts the following technical solution:

[0006] A method for calibrating a galvanometer system, characterized by comprising the following steps:

[0007] S1. Establish an error analysis model for the galvanometer system. The error analysis model is used to quantitatively analyze multiple error sources that affect the correction accuracy, so as to determine the contribution value of each error source to the total correction accuracy.

[0008] S2. Determine the correction accuracy target based on the error analysis model;

[0009] S3. Based on the target correction accuracy, perform an iterative correction process. Each iteration includes: obtaining the error value between the actual output position of the galvanometer system and the theoretical target position, and compensating and correcting the control parameters of the galvanometer system according to the error value.

[0010] S4. Repeat the iterative correction process until the error value meets the preset termination condition.

[0011] Furthermore, in S1, the error sources are galvanometer system error, visual measurement error, motion platform error, and environmental error;

[0012] Establish an error analysis model for the galvanometer system, including:

[0013] Establish separate sub-models for the galvanometer system error, visual measurement error, motion platform error, and environmental error;

[0014] Based on the statistical relationships between the various error sources, the error sub-models are synthesized to obtain the overall error model.

[0015] Furthermore, the various error sub-models are synthesized, including:

[0016] The root mean square synthesis method is used to synthesize the error sub-models: E_total = Where E_total is the theoretical total error, and E_i is the error value of each error source.

[0017] Furthermore, in step S3, obtaining the error value between the actual output position of the galvanometer system and the theoretical target position includes:

[0018] The control galvanometer system generates an array pattern covering the target scanning area on the calibration medium;

[0019] Images of the array pattern are acquired using a vision system;

[0020] Extract the actual position coordinates of each marker point in the array pattern;

[0021] The error value is obtained by calculating the deviation between the actual position coordinates and the theoretical position coordinates of each marker point.

[0022] Furthermore, in step S3, compensating and correcting the control parameters of the galvanometer system based on the error value includes:

[0023] Get the current error value corresponding to the current iteration number;

[0024] The current error value is partially compensated according to a preset ratio to generate a compensation amount;

[0025] The mapping parameters of the galvanometer controller are updated based on the compensation amount. These mapping parameters are used to map theoretical coordinates to compensated actual control coordinates.

[0026] Furthermore, the step of partially compensating the current error value according to a preset ratio includes:

[0027] For the k-th iteration, the compensation amount Compensation_k(i,j) satisfies: Compensation_k(i,j) = Compensation_{k-1}(i,j) + α × Error_k(i,j), where α is a preset scaling factor, 0 < α < 1, and Error_k(i,j) is the error value of the (i,j)-th marker point measured in the k-th iteration, where i and j are the row and column numbers corresponding to each marker point in the array, respectively.

[0028] Error_k(i,j) = P_theory(i,j) - P_measured_k(i,j); where P_theory(i,j) is the theoretical position coordinates corresponding to the (i,j)th marker, and P_measured_k(i,j) is the actual position coordinates of the (i,j)th marker measured in the kth iteration.

[0029] P_theory(i,j) = P_origin + (i×Δx, j×Δy) + (ΔX, ΔY); where P_origin is the coordinate of the starting point, Δx and Δy are the horizontal and vertical spacing of the array, respectively, and (ΔX, ΔY) is the relative offset between the origin of the galvanometer system's scanning coordinate system and the center of the visual system's field of view.

[0030] Furthermore, in S4, the preset termination condition is: after the k-th iteration, the absolute value of the largest error value among all marked points is less than the correction accuracy target.

[0031] Furthermore, the iterative correction process simultaneously executes environmental parameter control, stabilizing the working environment temperature at 20±0.5℃ and the relative humidity at 45±5% RH, and isolating environmental vibrations in the frequency range of 1~100Hz.

[0032] In addition, the present invention also provides a galvanometer system calibration device for the above-mentioned galvanometer system calibration method, comprising:

[0033] A galvanometer system is used to output a laser beam to form an array pattern under the drive of a control signal;

[0034] A vision system is used to acquire images of the array pattern and extract the actual position coordinates of each marker point in the array pattern;

[0035] A motion platform for carrying a calibration medium and moving the calibration medium in at least one direction;

[0036] A control system is connected to the galvanometer system, the vision system, and the motion platform, respectively. The control system includes:

[0037] The error analysis module is used to establish an error analysis model for the galvanometer system. The error analysis model is used to quantitatively analyze multiple error sources that affect the correction accuracy.

[0038] The iterative correction module is used to determine the correction accuracy target based on the error analysis model and to execute the iterative correction process. Each iteration includes compensating and correcting the control parameters of the galvanometer system based on the error value between the actual output position of the galvanometer system and the theoretical target position, until the error value meets the preset termination condition.

[0039] Furthermore, the accuracy of the galvanometer system, vision system, and motion platform is selected based on the quantitative analysis results of the corresponding error sources using the error analysis model.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] (1) The galvanometer system calibration method provided by this invention establishes an error analysis model of the galvanometer system to clarify the theoretical upper limit of each error source, and makes hardware selection and accuracy budget allocation accordingly, ensuring that the error of each link is within a controllable range, thereby guaranteeing the feasibility of the final accuracy from the source; and adopts iterative calibration instead of one-time full compensation, which can not only quickly converge the accuracy, but also avoid the oscillation divergence caused by overcompensation, significantly improving the stability and convergence reliability of the calibration process; at the same time, the whole process is automated, without the need for manual reading, manual adjustment or professional two-dimensional equipment, which significantly improves the calibration efficiency and reduces the operation threshold and equipment cost.

[0042] (2) The galvanometer system calibration method provided by the present invention uses an array pattern marking that covers the entire target scanning area, rather than single-point or local calibration. The actual position coordinates of each marking point of the array pattern are automatically collected, identified and located by the vision system, so as to realize large-area, high-density and automated position deviation measurement, and avoid edge accuracy failure caused by local calibration.

[0043] (3) The calibration accuracy of the galvanometer system calibration method provided by the present invention is improved from ±0.07mm to ±0.01mm, which is a significant improvement in accuracy. At the same time, the calibration time is also shortened from more than 1 hour in the prior art to less than 30 minutes, which greatly improves efficiency.

[0044] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating the calibration method for the galvanometer system of the present invention;

[0046] Figure 2 This is a schematic diagram of a 17×17 array of crosshair markings in an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of error calculation in an embodiment of the present invention;

[0048] Figure 4 This is a convergence curve diagram of iterative correction in an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the structure of the galvanometer system correction device of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an abutting connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0053] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] like Figure 1 As shown, this embodiment provides a galvanometer system calibration method, characterized by the following steps:

[0055] S1. Establish an error analysis model for the galvanometer system. The error analysis model is used to quantitatively analyze multiple error sources that affect the correction accuracy, so as to determine the contribution value of each error source to the total correction accuracy.

[0056] S2. Determine the correction accuracy target based on the error analysis model.

[0057] S3. Based on the target correction accuracy, perform an iterative correction process. Each iteration includes: obtaining the error value between the actual output position of the galvanometer system and the theoretical target position, and compensating and correcting the control parameters of the galvanometer system according to the error value.

[0058] S4. Repeat the iterative correction process until the error value meets the preset termination condition.

[0059] In step S1 above, as Figure 3 As shown, the calibration accuracy of the galvanometer system is affected by a variety of error factors. The main error sources can be summarized into the following four categories: galvanometer system error (E_galvo), visual measurement error (E_camera), motion platform error (E_stage), and environmental error (E_env).

[0060] (1) The galvanometer system error refers to the positioning deviation generated by the galvanometer motor during the scanning process. It mainly comes from the motor drive control error, mechanical transmission clearance, and nonlinear error of scanning angle and displacement conversion.

[0061] Motor drive control error (E_drive): The galvanometer motor uses closed-loop control. Quantization errors in the drive signal and discretization errors in the control algorithm can cause deviations between the angular displacement output and the expected value. For example, the galvanometer system used in this invention is equipped with a 16-bit DAC driver, with a theoretical control accuracy of 0.005°, corresponding to an angular displacement error of approximately ±0.001°. The calculation method for its motor drive control error is as follows:

[0062] The 16-bit DAC has a resolution of 2^16 = 65536 levels, corresponding to a maximum scanning angle of ±20° (total range 40°) for the galvanometer. Therefore, the angle corresponding to each level is: Δθ_min = 40° / 65536 ≈ 0.00061°. With a scanning area of ​​200mm and a working distance L = 400mm, the angle error is converted into a linear displacement error.

[0063] Δx = L × tan(Δθ) ≈ L × Δθ (radians) = 400mm × (0.00061 × π / 180)≈ 0.0043μm

[0064] Considering the discretization error and noise effect of the control algorithm, the actual drive control error is about 50 times the theoretical value, i.e., ±0.2μm.

[0065] Mechanical transmission clearance (E_mechanical): The galvanometer reflector is connected to the motor shaft via a flexible hinge. Minor assembly gaps and material elastic deformation can cause angular transmission errors, which are controlled through precision machining and assembly processes. Measurement method for mechanical transmission clearance: A laser interferometer is used to perform bidirectional positioning tests on the galvanometer. By approaching the same target position in both forward and reverse directions, the difference between the two positioning measurements is measured. For example, the mechanical transmission clearance of the galvanometer system of this invention is controlled within ±1 μm.

[0066] Nonlinear error in scanning angle and displacement conversion (E_nonlinear): Galvanometer scanning uses a conversion from polar coordinates to rectangular coordinates, which introduces inherent nonlinear error during large-angle scanning. When the scanning angle θ≤15°, sin(θ)≈θ, and the nonlinear error can be ignored; when θ>15°, a correction factor needs to be introduced. Calculation of nonlinear error: The displacement formula for galvanometer scanning is x = f × tan(θ), where f is the focal length (400mm). At the maximum scanning angle θ=20°, the ideal displacement is: x_ideal = f× θ = 400mm × 20° × π / 180 ≈ 139.6mm, the actual displacement is: x_actual = f × tan(20°) =400mm × 0.364 ≈ 145.6mm, and the nonlinear error is: Δx_nonlinear = x_actual - x_ideal ≈ 6mm (at the edge). This nonlinear error is compensated by a lookup table method, and the residual after compensation is approximately ±0.5μm.

[0067] Considering the three sources of galvanometer systematic error mentioned above, a sub-model of galvanometer systematic error is established using the root mean square synthesis method: E_galvo = .

[0068] Substituting the above errors, we get E_galvo = ≈ 1.14μm. Considering factors such as long-term stability, temperature drift, and component aging, a safety factor K=1.75 is introduced, resulting in E_galvo(actual) = K×E_galvo(theoretical) = 1.75 × 1.14μm ≈ 2μm. This value has been experimentally verified. Within a 200mm×200mm area, the galvanometer underwent 1000 repeated positioning tests. The statistical results show that the maximum positioning error is ±1.8μm, and the standard deviation is 0.6μm. Therefore, this invention rounds it to ±2μm as the theoretical repeatability positioning accuracy of the galvanometer system.

[0069] (2) Visual measurement error refers to the error generated when acquiring images and extracting the coordinates of marker points through an industrial camera. It is mainly determined by the following factors: camera resolution limitation, lens distortion error, and image processing algorithm error. Therefore, the root mean square synthesis method is used to establish a visual measurement error sub-model for these three error sources.

[0070] This invention is equipped with a 20-megapixel industrial camera with a single field of view of 4mm×5mm. Taking all factors into account, the theoretical positioning error of the vision system is E_camera = ±1μm.

[0071] (3) Motion platform error refers to the multi-source error generated by the motion platform during the movement process, including positioning error, verticality error and straightness error; the motion platform error sub-model is established by using the root mean square synthesis method for these three error sources.

[0072] A high-precision linear motor drives the XY-axis motion platform. The positioning errors (ΔX, ΔY) are determined by the motor encoder accuracy and the lead screw pitch error. This galvanometer system uses a 20nm resolution encoder, achieving a positioning error better than ±0.5μm. The perpendicularity error (Δperpendicularity) is the orthogonal deviation between the X and Y axis motion directions, calibrated using a laser interferometer, with the perpendicularity error controlled within ±2μm / m. The straightness error (Δstraightness) is the deviation of the motion trajectory from the ideal straight line, including horizontal and vertical straightness, with a combined error of approximately ±2μm. The motion platform error sub-model is E_stage = Substituting the various error values, we calculate E_stage ≈ 2.9μm. Considering the cumulative error under actual working conditions, this invention adopts a safety factor of 1.03, and the final comprehensive error of the motion platform is E_stage ≈ ±3μm.

[0073] (4) Environmental error refers to the influence of working environment factors on the accuracy of correction, mainly including temperature drift error, vibration interference error and humidity influence; the three errors are combined using the root mean square method to establish an environmental error sub-model.

[0074] Temperature drift error: Temperature changes cause thermal expansion and contraction of materials, affecting the dimensions of mechanical structures; the main materials of the galvanometer system correction device in this invention are aluminum alloy and steel, with linear expansion coefficients of 23×10⁻⁶ respectively. -6 / ℃ and 11×10 -6 / ℃, within a 200mm stroke range, the error produced by a 1℃ temperature change is approximately: ΔL = L × α × ΔT = 200mm × 23 × 10 -6 / ℃ × 1℃ = 4.6μm. The temperature is stabilized at 20±0.5℃ by the environmental control unit, and the temperature drift error can be controlled within ±2.3μm.

[0075] Vibration interference error: Environmental vibration can cause platform shaking, affecting the stability of image acquisition. Vibration in the range of 1 to 100 Hz can be suppressed by passive vibration isolation pads. The positioning error caused by vibration is about ±1 μm.

[0076] Humidity effect: Changes in humidity can cause materials to absorb moisture and expand, especially for calibration media made of paper. By controlling the relative humidity within the range of 45±5%RH, the error caused by humidity is approximately ±0.7μm.

[0077] Environmental error sub-model E_env = Substituting the various error values, we get E_env≈2.6μm. Considering the uncertainty of environmental fluctuations, we take a safety factor of 1.5, and the final environmental error is E_env≈±4μm.

[0078] Establish an error analysis model for the galvanometer system, including:

[0079] Establish separate sub-models for the galvanometer system error, visual measurement error, motion platform error, and environmental error;

[0080] Based on the statistical relationships between the various error sources, the error sub-models are synthesized to obtain the total error model. Specifically, the synthesis of the various error sub-models includes: using the root mean square synthesis method to synthesize the various error sub-models: E_total = Where E_total is the theoretical total error, and E_i is the error value of each error source.

[0081] For example, based on the above error analysis, this invention establishes a total error synthesis model, where each error source is independent, and the sum-of-squares (RSS) method is used for error synthesis:

[0082] E_total =

[0083] Substituting the error components, we get:

[0084] E_total = ≈ 5.5μm (theoretical value)

[0085] Considering the existence of unmodeled errors and measurement uncertainties in the actual system, and taking a safety factor of approximately 1.8, the actual conservative estimate of the total error is:

[0086] E_total ≈ ±10μm (conservative estimate)

[0087] The error analysis results show that, under the condition of reasonable control of each error source, it is theoretically feasible for the galvanometer system to achieve a correction accuracy of ±0.01mm (i.e. ±10μm) within a 200mm×200mm area.

[0088] Based on the conclusions of the above error analysis, we can guide the hardware selection, accuracy allocation, and calibration process design of the galvanometer system calibration device.

[0089] Specifically, such as Figure 5 As shown, the hardware components of the galvanometer system calibration device include a galvanometer system 1, a vision system 2, a motion platform 5, and a control system 6. The galvanometer system 1 uses a galvanometer motor with a scanning range of 200mm × 200mm and a theoretical repeatability of ±2μm. The vision system 2 is equipped with a 20-megapixel industrial camera with a single field of view of 4mm × 5mm and a theoretical visual positioning accuracy of ±1μm. The motion platform 5 uses a high-precision linear motor to drive the XY-axis motion platform, with positioning accuracy better than 0.5μm for each axis. It is equipped with passive vibration isolation pads. An adsorption platform 4 is mounted on the motion platform 5 to fix the calibration medium 3, ensuring a tight fit between the calibration medium 3 and the adsorption platform 4. The vision system 2 is also equipped with a hand-cranked lifting platform to adjust the focal length between the camera and the calibration plane. The control system 6 is electrically connected to the galvanometer system 1, the vision system 2, and the motion platform 5. The control system 6 includes an environmental control unit to control the operating environment temperature within the range of 20±0.5℃ and the relative humidity within the range of 45±5%RH. During assembly, place the marble platform on the vibration isolation pad to ensure the platform is level. Install the motion platform 5 on the marble platform, with the motion range covering a 200mm×200mm area. Fix the adsorption platform 4 on the motion platform 5. Install the galvanometer system 1 above the motion platform 5, ensuring the scanning range covers a 200mm×200mm area. Install the vision system 2 (including a 20-megapixel camera, matching lens, light source, etc.) on one side of the motion platform via a hand-cranked lifting platform. Adjust the focus to make the calibration plane clearly imaged.

[0090] In step S3 above, the error value between the actual output position of the galvanometer system and the theoretical target position is obtained, including:

[0091] S31. Control the galvanometer system to generate an array pattern covering the target scanning area on the calibration medium.

[0092] Preferably, system calibration is performed before generating the array pattern. Specifically, the image pixel coordinates and actual physical coordinates of the vision system are mapped and calibrated, and the relative offset between the origin of the galvanometer system scanning coordinate system and the center of the vision system's field of view is calibrated.

[0093] The vision system is equipped with a 20-megapixel industrial camera with a single field of view of 4mm×5mm and a visual positioning accuracy of no less than ±1μmm. Specifically, a standard calibration ruler is placed on the adsorption platform, and the motion platform is controlled to move so that the calibration ruler is successively located at different positions in the field of view of the industrial camera. Multiple images are captured, the standard scale points on the calibration ruler are extracted, and the mapping relationship between the image pixel coordinates and the actual physical coordinates is established. After calibration, the camera parameters are saved. This step only needs to be repeated when changing the camera model.

[0094] The relative offset includes a horizontal offset ΔX and a vertical offset ΔY, calculated by locating the origin of the galvanometer system's scanning coordinate system and the center of the vision system's field of view in the mechanical coordinate system using standard markers. Specifically, the process of determining the relative offset between the origin of the galvanometer system's scanning coordinate system and the center of the industrial camera's field of view is as follows: The galvanometer system marks a positioning marker at the center of the calibration medium. The motion platform is moved until this positioning marker is located at the center of the industrial camera's field of view. The coordinates (X1, Y1) of the motion platform at this point are recorded. The galvanometer system then marks another positioning marker at the center of the calibration medium (theoretically coinciding with the first one). The deviation (ΔX, ΔY) of this positioning marker relative to the center of the industrial camera's field of view is measured by the vision system. This deviation is the relative offset between the galvanometer center and the industrial camera center and is stored. Calibration paper can be used as the calibration medium.

[0095] This independently calibrated galvanometer system can scan the relative offset between the origin of the coordinate system and the center of the field of view of the vision system, eliminate the inherent deviation between the two coordinate systems, achieve high-precision unification of the theoretical coordinates of the galvanometer, the visual measurement coordinates, and the mechanical platform coordinates, and solve the systematic deviation caused by cross-coordinate system measurement.

[0096] Optionally, the array pattern generated by the galvanometer system on the calibration medium can be any one of crosshairs, dots, or square marks; in this embodiment, such as Figure 2 As shown, the target scanning area is specifically 200mm×200mm, and the array pattern is a 17×17 array of crosshair markings, with the array spacing (12.5mm) evenly distributed to cover the entire target scanning area.

[0097] S32. Acquire an image of the array pattern using a vision system.

[0098] S33. Extract the actual position coordinates of each marker point in the array pattern.

[0099] Specifically, the motion platform is driven to move the calibration medium, so that each marker point of the array pattern enters the center of the vision system in sequence. The actual coordinates P_measured(i,j) of the center of the marker point (such as a crosshair) are extracted, which are the actual position coordinates of the marker point.

[0100] S34. Calculate the deviation between the actual position coordinates and the theoretical position coordinates of each marker point to obtain the error value.

[0101] The theoretical position coordinates of each marker point are calculated based on the target scanning area size, the array spacing of the array pattern, and the relative offset calibrated by the system.

[0102] Specifically, the formula for calculating the theoretical position coordinates of each positioning mark is as follows: P_theory(i,j) = P_origin + (i×Δx, j×Δy) + (ΔX, ΔY); where P_theory(i,j) is the theoretical position coordinates of the (i,j)th mark, P_origin is the starting point coordinates, generally (0,0), i and j are the row and column numbers of the array, Δx and Δy are the horizontal and vertical spacing of the array pattern, and (ΔX, ΔY) is the relative offset between the origin of the galvanometer system scanning coordinate system and the center of the visual system's field of view.

[0103] Then the error value Error_(i,j) = P_theory(i,j) - P_measured_(i,j).

[0104] Furthermore, in S3 above, the control parameters of the galvanometer system are compensated and corrected based on the error value, including:

[0105] S35. Obtain the current error value corresponding to the current iteration number.

[0106] S36. Perform partial compensation on the current error value according to a preset ratio to generate a compensation amount.

[0107] Specifically, for the k-th iteration, the compensation amount Compensation_k(i,j) satisfies: Compensation_k(i,j) = Compensation_{k-1}(i,j) + α × Error_k(i,j), where α is a preset scaling factor, 0 < α < 1, and Error_k(i,j) is the error value of the (i,j)-th marker point measured in the k-th iteration, where i and j are the row and column numbers corresponding to each marker point in the array, respectively.

[0108] Error_k(i,j) = P_theory(i,j) - P_measured_k(i,j); where P_theory(i,j) is the theoretical position coordinates corresponding to the (i,j)th marker, and P_measured_k(i,j) is the actual position coordinates of the (i,j)th marker measured in the kth iteration.

[0109] In this embodiment, each iteration compensates and corrects by half of the current error value, i.e., α is 0.5. By using this iterative correction strategy instead of a one-time full compensation, the error sequence can be guaranteed to decrease monotonically and eventually converge to near zero. This can not only quickly improve the accuracy but also avoid oscillations and divergences caused by overcompensation, significantly improving the stability and convergence reliability of the correction process.

[0110] S37. Update the mapping parameters of the galvanometer controller according to the compensation amount. The mapping parameters are used to map the theoretical coordinates to the compensated actual control coordinates.

[0111] After updating the mapping parameters of the galvanometer controller, when the galvanometer receives the original theoretical coordinate command in the next cycle, it automatically superimposes the compensation coordinate points to correct the actual output position. That is, in the next cycle, P_theory(i,j) remains unchanged, while P_measured(i,j) is corrected. P_measured(i,j) continuously approaches P_theory(i,j), thus achieving accuracy convergence.

[0112] In step S4 above, the preset termination condition is: after the k-th iteration, the absolute value of the largest error value among all marked points is less than the correction accuracy target.

[0113] In this embodiment, the target correction accuracy is ±0.01mm, that is, the termination condition for iterative correction is max|Error_k(i,j)|<0.01mm.

[0114] The optimized system simultaneously controls environmental parameters during the calibration process, stabilizing the operating temperature at 20±0.5℃ and the relative humidity at 45±5% RH, while isolating environmental vibrations within the 1~100Hz frequency range. Through closed-loop temperature and humidity control and vibration reduction in the specified frequency band, the system reduces additional errors introduced by environmental disturbances, improves measurement stability, shortens the number of iterations, and ensures stable calibration accuracy.

[0115] Taking the calibration of a 200mm×200mm galvanometer system as an example, the calibration process described above should be followed. Figure 4As shown, in the first iteration: the galvanometer is controlled to mark a 17×17 array of crosshairs with an array spacing of 12.5mm (200mm / 16). The motion platform is moved sequentially so that each crosshair enters the camera's field of view. The deviation between the actual and theoretical positions of each crosshair is measured, the compensation value is calculated, and the galvanometer mapping table is updated. The maximum error is measured to be approximately ±0.05mm. In the second iteration: the updated galvanometer mapping table is used to remark the 17×17 array of crosshairs, and the measurement and compensation process is repeated. The maximum error is measured to be approximately ±0.02mm. In the third iteration: the updated galvanometer mapping table from the second iteration is used again to remark the 17×17 array of crosshairs, and the measurement and compensation process is repeated. The maximum error is measured to be approximately ±0.008mm, which meets the ±0.01mm requirement, and the iteration is terminated.

[0116] Using this calibrated galvanometer system, 20 test points were randomly selected within a 200mm×200mm area for calibration verification. The crosshairs of the galvanometer were controlled, and the deviation between the actual and theoretical positions was measured using a vision system. The verification results are as follows: the maximum deviation of all test points was 0.008mm, the minimum deviation was 0.002mm, and the average deviation was 0.005mm. The verification results show that the deviation of all test points is less than ±0.01mm, indicating successful calibration.

[0117] In addition, such as Figure 5 As shown, this embodiment also provides a galvanometer system calibration device for the above-described galvanometer system calibration method, comprising:

[0118] Galvanometer system 1 is used to output a laser beam to form an array pattern under the drive of a control signal;

[0119] Vision system 2 is used to acquire images of the array pattern and extract the actual position coordinates of each marker point in the array pattern;

[0120] Motion platform 5 is used to carry calibration medium 3 and drive calibration medium 3 to move in at least one direction;

[0121] The control system 6 is connected to the galvanometer system 1, the vision system 2, and the motion platform 5, respectively. The control system includes:

[0122] The error analysis module is used to establish an error analysis model for the galvanometer system. The error analysis model is used to quantitatively analyze multiple error sources that affect the correction accuracy.

[0123] The iterative correction module is used to determine the correction accuracy target based on the error analysis model and to execute the iterative correction process. Each iteration includes compensating and correcting the control parameters of the galvanometer system based on the error value between the actual output position of the galvanometer system and the theoretical target position, until the error value meets the preset termination condition.

[0124] Specifically, in this embodiment, the accuracy of the galvanometer system 1, vision system 2, and motion platform 5 is selected based on the quantitative analysis results of the corresponding error sources using the aforementioned error analysis model.

[0125] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A method for calibrating a galvanometer system, characterized in that, Includes the following steps: S1. Establish an error analysis model for the galvanometer system. The error analysis model is used to quantitatively analyze multiple error sources that affect the correction accuracy, so as to determine the contribution value of each error source to the total correction accuracy. S2. Determine the correction accuracy target based on the error analysis model; S3. Based on the target correction accuracy, perform an iterative correction process. Each iteration includes: obtaining the error value between the actual output position of the galvanometer system and the theoretical target position, and compensating and correcting the control parameters of the galvanometer system according to the error value. S4. Repeat the iterative correction process until the error value meets the preset termination condition.

2. The galvanometer system calibration method as described in claim 1, characterized in that, In S1, the error sources are galvanometer system error, visual measurement error, motion platform error, and environmental error; Establish an error analysis model for the galvanometer system, including: Establish separate sub-models for the galvanometer system error, visual measurement error, motion platform error, and environmental error; Based on the statistical relationships between the various error sources, the error sub-models are synthesized to obtain the overall error model.

3. The galvanometer system calibration method as described in claim 2, characterized in that, The various error sub-models are synthesized, including: The root mean square synthesis method is used to synthesize the error sub-models: E_total = Where E_total is the theoretical total error, and E_i is the error value of each error source.

4. The galvanometer system calibration method as described in claim 1, characterized in that, In step S3, obtaining the error value between the actual output position of the galvanometer system and the theoretical target position includes: The control galvanometer system generates an array pattern covering the target scanning area on the calibration medium; Images of the array pattern are acquired using a vision system; Extract the actual position coordinates of each marker point in the array pattern; The error value is obtained by calculating the deviation between the actual position coordinates and the theoretical position coordinates of each marker point.

5. The galvanometer system calibration method as described in claim 4, characterized in that, In step S3, the control parameters of the galvanometer system are compensated and corrected based on the error value, including: Get the current error value corresponding to the current iteration number; The current error value is partially compensated according to a preset ratio to generate a compensation amount; The mapping parameters of the galvanometer controller are updated based on the compensation amount. These mapping parameters are used to map theoretical coordinates to compensated actual control coordinates.

6. The galvanometer system calibration method as described in claim 5, characterized in that, The step of partially compensating the current error value according to a preset ratio includes: For the k-th iteration, the compensation amount Compensation_k(i,j) satisfies: Compensation_k(i,j) = Compensation_{k-1}(i,j) + α × Error_k(i,j), where α is a preset scaling factor, 0 < α < 1, and Error_k(i,j) is the error value of the (i,j)-th marker point measured in the k-th iteration, where i and j are the row and column numbers corresponding to each marker point in the array, respectively. Error_k(i,j) = P_theory(i,j) - P_measured_k(i,j); where P_theory(i,j) is the theoretical position coordinates corresponding to the (i,j)th marker, and P_measured_k(i,j) is the actual position coordinates of the (i,j)th marker measured in the kth iteration. P_theory(i,j) = P_origin + (i×Δx, j×Δy) + (ΔX, ΔY); where P_origin is the coordinate of the starting point, Δx and Δy are the horizontal and vertical spacing of the array, respectively, and (ΔX, ΔY) is the relative offset between the origin of the galvanometer system's scanning coordinate system and the center of the visual system's field of view.

7. The galvanometer system calibration method as described in claim 6, characterized in that, In S4, the preset termination condition is: after the k-th iteration, the absolute value of the largest error value among all marked points is less than the correction accuracy target.

8. The galvanometer system calibration method as described in claim 1, characterized in that, The iterative correction process simultaneously executes environmental parameter control, stabilizing the working environment temperature at 20±0.5℃ and the relative humidity at 45±5% RH, and isolating environmental vibrations in the frequency range of 1~100Hz.

9. A galvanometer system calibration device, characterized in that, The calibration method for the galvanometer system according to any one of claims 1-8 includes: A galvanometer system is used to output a laser beam to form an array pattern under the drive of a control signal; A vision system is used to acquire images of the array pattern and extract the actual position coordinates of each marker point in the array pattern; A motion platform for carrying a calibration medium and moving the calibration medium in at least one direction; A control system is connected to the galvanometer system, the vision system, and the motion platform, respectively. The control system includes: The error analysis module is used to establish an error analysis model for the galvanometer system. The error analysis model is used to quantitatively analyze multiple error sources that affect the correction accuracy. The iterative correction module is used to determine the correction accuracy target based on the error analysis model and to execute the iterative correction process. Each iteration includes compensating and correcting the control parameters of the galvanometer system based on the error value between the actual output position of the galvanometer system and the theoretical target position, until the error value meets the preset termination condition.

10. The galvanometer system calibration device as described in claim 9, characterized in that, The accuracy of the galvanometer system, vision system, and motion platform is selected based on the quantitative analysis results of the corresponding error sources using the error analysis model.

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