A laser calibration method and system

Abstract

This invention relates to the field of laser calibration technology, and discloses a laser calibration method and system. The method involves acquiring the real-time output power value and spot morphology parameter set of the beam emission source in a laser processing system; calculating the transmission path offset and energy density dispersion based on the spatial vector differences of different spot morphology parameter sets; constructing a dynamic response function of optical power versus calibration depth based on the energy density dispersion, the beam's focal length compensation coefficient, and the real-time output power value; calculating the fitting weight matrix based on the rate of change of the response slope of the dynamic response function; and performing multi-band coordinated adjustment of the beam emission source's output power based on the convergence characteristics of the fitting weight matrix to achieve laser calibration control. By constructing the optical power versus calibration depth dynamic response function and the fitting weight matrix, multi-band coordinated adjustment and predictive feedforward control are achieved, improving the laser processing system's dynamic compensation capability for transmission path offset and the stability of processing quality.

Description

Technical Field

[0001] This invention relates to the field of laser calibration technology, and more specifically, to a laser calibration method and system. Background Technology

[0002] Laser processing calibration refers to the technology of adjusting the laser output power and beam path parameters to compensate for transmission deviations caused by factors such as thermal drift, mechanical vibration and aging of optical components, so as to maintain the quality of the processing beam and positioning accuracy. It is a key supporting technology to ensure the long-term stable operation of the laser processing system.

[0003] Existing technologies often employ fixed power output combined with independent optical path mechanical fine-tuning, or use simple closed-loop feedback to correct a single parameter, thereby correcting beam transmission path offset to achieve the calibration target. However, fixed power in existing technologies is difficult to adapt to dynamically changing transmission offsets, causing calibration accuracy to decrease with environmental disturbances. Furthermore, the amount of compensation information contained in single-parameter adjustment is insufficient, affecting dynamic response speed; independent multi-parameter adjustment lacks a coordination mechanism, leading to mutual interference between adjustment values ​​and affecting the stability and consistency of processing quality. Especially in non-steady-state processing, the dispersion of beam energy density distribution and transmission offset exhibit strong coupling characteristics. Traditional methods cannot construct the dynamic response relationship between optical power and calibration depth in real time, causing adjustment to lag behind disturbance changes and making it difficult to meet the stringent requirements of precision machining for beam stability. Summary of the Invention

[0004] This invention provides a laser calibration method and system. By constructing a dynamic response function of optical power-calibration depth and an adaptation weight matrix, it achieves multi-band coordinated adjustment and predictive feedforward control, thereby improving the dynamic compensation capability of the laser processing system for transmission path offset and the stability of processing quality.

[0005] To achieve the above objectives, the present invention provides a laser calibration method, comprising:

[0006] Acquire the real-time output power value of the beam emission source in the laser processing system and the set of beam spot morphology parameters acting on the workpiece surface; Based on the spatial vector differences of the light spot morphology parameter set at different spatial sampling points, the transmission path offset and energy density dispersion of the light beam are calculated. Based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value, a dynamic response function of optical power-calibration depth is constructed. Based on the rate of change of the response slope of the dynamic response function, the adaptation weight matrix between each output power level and the transmission path offset is calculated. Based on the convergence characteristics of the adaptation weight matrix, the output power of the beam emission source is adjusted in a multi-band coordinated manner to achieve laser calibration control.

[0007] Furthermore, based on the spatial vector differences in the light spot morphology parameter sets at different spatial sampling points, the propagation path offset and energy density dispersion of the light beam are calculated, including: The beam morphology parameter set is simultaneously captured at at least three non-collinear spatial sampling points using a preset beam quality analyzer. The beam morphology parameter set includes the beam center coordinates, ellipticity, peak power density, and effective radius. Based on the homogeneous coordinate transformation of the center coordinates of the light spot at each sampling point, the spatial angle and translation vector between the actual optical axis of the beam and the reference optical axis are calculated, and the spatial angle and the translation vector are combined to form the transmission path offset. The energy density dispersion is calculated based on the normalized distribution deviation of the peak power density at each sampling point and the surface integral difference of the effective radius.

[0008] Furthermore, based on the normalized distribution deviation of the peak power density at each sampling point and the surface integral difference of the effective radius, the energy density dispersion is calculated, including: The peak power density at each sampling point is fitted with a fundamental Gaussian distribution to obtain the root mean square error between the actual distribution function and the theoretical distribution function. Calculate the two-dimensional integral value of the power density within the effective radius of each sampling point, and determine the relative deviation rate between the maximum and minimum integral values ​​among all sampling points; The weighted sum of the root mean square error values ​​is nonlinearly coupled with the relative deviation rate to output the energy density dispersion, wherein the weighting coefficients are dynamically adjusted according to the spatial angle.

[0009] Furthermore, based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value, a dynamic response function of optical power-calibration depth is constructed, including: Based on the thermal expansion characteristic curve of the optical lens of the laser processing system, a lookup table of focal length compensation coefficients under the current ambient temperature is established. Obtain material removal depth samples corresponding to different output power values ​​from historical processing data, and obtain the baseline response curve by fitting the least squares method. The energy density dispersion is introduced as a correction factor into the baseline response curve to construct a three-dimensional response surface that includes the focal length compensation coefficient independent variable, the real-time output power value dependent variable, and the calibration depth output. The dynamic response function is extracted by performing a differential operation along the power value dimension on the three-dimensional response surface.

[0010] Furthermore, based on the rate of change of the response slope of the dynamic response function, the adaptation weight matrix between each output power level and the transmission path offset is calculated, including: The real-time output power value is divided into N discrete gear intervals, and the ratio of the first derivative to the second derivative of the dynamic response function is calculated for each gear interval. The ratio is mapped to a preset stability evaluation interval to generate initial weight values ​​for each gear interval; Based on the direction vector of the transmission path offset, the initial weight value of each gear interval is spatially projected and corrected. The weight value is attenuated when the orthogonality between the offset direction and the power adjustment direction increases. The corrected weight values ​​are used to construct a two-dimensional matrix according to the gear range and the offset magnitude. After normalization, the adaptation weight matrix is ​​obtained.

[0011] Furthermore, based on the convergence characteristics of the adaptation weight matrix, the output power of the beam emission source is adjusted in a multi-band coordinated manner, including: Extract the eigenvalue sequence of the adaptation weight matrix. When the difference between the largest eigenvalue and the second largest eigenvalue exceeds a preset separation threshold, it is determined to be a single-mode dominant convergence mode, and a fast coarse adjustment strategy is executed. When all feature values ​​are distributed within a preset band interval, it is determined to be a multi-mode coupling convergence mode, and a refined collaborative adjustment strategy is initiated. The refined collaborative adjustment strategy includes superposition modulation of high-frequency power jitter components and low-frequency trend components. Based on the spectral distribution of the convergence characteristics, the power adjustment ratio of the coarse adjustment channel and the fine adjustment channel is automatically allocated, wherein the coarse adjustment channel acts on the pump current of the solid-state laser, and the fine adjustment channel acts on the diffraction efficiency of the acousto-optic modulator.

[0012] Furthermore, after initiating a refined and coordinated adjustment strategy, it also includes: Acquire the laser medium temperature field distribution data and the cavity length drift of the beam emission source; The focal position shift caused by the thermal lensing effect is calculated based on the temperature field distribution data, and a first compensation power value is generated. The power fluctuation caused by longitudinal mode competition is calculated based on the cavity length drift, and a second compensation power value is generated. The first compensation power value and the second compensation power value are vector synthesized to obtain the environmental disturbance feedforward compensation amount, which is then superimposed on the output of the refined collaborative adjustment strategy.

[0013] Furthermore, based on the convergence characteristics of the adaptation weight matrix, after multi-band coordinated adjustment of the output power of the beam emission source, the method further includes: Establish a trajectory database of the output power adjustment amount and the transmission path offset, the trajectory database recording parameter pairs before and after each adjustment; A long short-term memory network is used to perform time-series modeling on the change trajectory database to predict the optimal power pre-regulation amount within a specific future time window.

[0014] Furthermore, based on the convergence characteristics of the adaptation weight matrix, after multi-band coordinated adjustment of the output power of the beam emission source, the method further includes: When the prediction confidence exceeds the preset confidence threshold, a preset proportion of the optimal power pre-adjustment amount is injected in advance at the current moment as a feedforward control amount, and the remaining proportion is dynamically corrected by real-time feedback control.

[0015] To achieve the above objectives, the present invention also provides a laser calibration system, comprising: The parameter acquisition module is used to acquire the real-time output power value of the beam emission source in the laser processing system and the set of light spot morphology parameters acting on the workpiece surface; The first calculation module is used to calculate the transmission path offset and energy density dispersion of the light beam based on the spatial vector difference of the light spot morphology parameter set at different spatial sampling points. The function construction module is used to construct a dynamic response function of optical power-calibration depth based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value. The second calculation module is used to calculate the adaptation weight matrix between each output power level and the transmission path offset based on the rate of change of the response slope of the dynamic response function. The laser calibration module is used to perform multi-band coordinated adjustment of the output power of the beam emission source based on the convergence characteristics of the adaptation weight matrix, thereby realizing laser calibration control.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses a laser calibration method and system. The method acquires the real-time output power value and spot morphology parameter set of the beam emission source in a laser processing system. Based on the spatial vector differences of different spot morphology parameter sets, it calculates the transmission path offset and energy density dispersion. Based on the energy density dispersion, the beam's focal length compensation coefficient, and the real-time output power value, it constructs a dynamic response function of optical power versus calibration depth. Based on the rate of change of the response slope of the dynamic response function, it calculates the fitting weight matrix. Based on the convergence characteristics of the fitting weight matrix, it performs multi-band coordinated adjustment of the beam emission source's output power to achieve laser calibration control. By constructing the optical power versus calibration depth dynamic response function and the fitting weight matrix, it achieves multi-band coordinated adjustment and predictive feedforward control, improving the laser processing system's dynamic compensation capability for transmission path offset and the stability of processing quality. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic flowchart of a laser calibration method according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of a laser calibration system according to an embodiment of the present invention is shown. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] In the description of this application, 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 application 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 application.

[0020] 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] The following is a description of preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0023] like Figure 1 As shown, an embodiment of the present invention discloses a laser calibration method, comprising: S110: Acquire the real-time output power value of the beam emission source in the laser processing system and the set of beam spot morphology parameters acting on the workpiece surface; S120: Based on the spatial vector difference of the light spot morphology parameter set at different spatial sampling points, the transmission path offset and energy density dispersion of the light beam are calculated. S130: Based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value, construct a dynamic response function of optical power-calibration depth; S140: Based on the rate of change of the response slope of the dynamic response function, calculate the adaptation weight matrix between each output power level and the transmission path offset; S150: Based on the convergence characteristics of the adaptation weight matrix, the output power of the beam emission source is adjusted in a multi-band coordinated manner to achieve laser calibration control.

[0024] In some embodiments of this application, the propagation path offset and energy density dispersion of the light beam are calculated based on the spatial vector differences of the light spot morphology parameter sets at different spatial sampling points, including: The beam morphology parameter set is simultaneously captured at at least three non-collinear spatial sampling points using a preset beam quality analyzer. The beam morphology parameter set includes the beam center coordinates, ellipticity, peak power density, and effective radius. Based on the homogeneous coordinate transformation of the center coordinates of the light spot at each sampling point, the spatial angle and translation vector between the actual optical axis of the beam and the reference optical axis are calculated, and the spatial angle and the translation vector are combined to form the transmission path offset. The energy density dispersion is calculated based on the normalized distribution deviation of the peak power density at each sampling point and the surface integral difference of the effective radius.

[0025] In this embodiment, the laser processing system refers to fiber laser cutting or welding equipment. The beam emission source is a ytterbium-doped fiber laser, and the real-time output power value is acquired by a built-in integrating sphere power meter. The sampling frequency is set to 10 times per second, with a range of 0 to 6000 watts. The beam morphology parameter set is obtained by a beam quality analyzer deployed in the processing area, including four core parameters: beam center coordinates, ellipticity, peak power density, and effective radius. The preset beam quality analyzer uses a CMOS sensor array in conjunction with a beam splitter group, with three sampling points deployed near the processing head. The first sampling point is located at the upper left corner of the processing area, the second sampling point is located at the lower right corner, and the third sampling point is located at the geometric center, forming a non-collinear triangular layout. Synchronous capture is achieved through a time-division multiplexing trigger mechanism. The controller sequentially triggers the analysis units of the three sampling points within each laser pulse cycle, with a timing interval of 10 microseconds to ensure the capture of the beam morphology of the same pulse. The beam center coordinates are calculated using an image moment algorithm to determine the centroid position of the beam grayscale distribution. The coordinate system has the lower left corner of the processing area as the origin, and the unit is millimeters. Ellipticity is defined as the ratio of the major axis to the minor axis of the beam, reflecting the focusing quality. Peak power density is the maximum power density within the beam spot region, measured in watts per square centimeter. Effective radius of action refers to the radial distance from which the power density drops to 1 / e² of the peak value. Homogeneous coordinate transformation converts the center coordinates of each sampling point to a unified reference coordinate system, calculating the angle between the actual optical axis direction vector and the reference optical axis (the z-axis perpendicular to the processing surface), for example, an angle of 1.5 degrees. The translation vector is the average deviation between the center coordinates of each sampling point and the theoretical center coordinates, for example, a translation of 0.3 mm in the x-direction and 0.2 mm in the y-direction. The transmission path offset is a weighted composite of the angle and the translation vector, with an angle weight of 0.6 and a translation weight of 0.4, resulting in a dimensionless offset value of 0.85.

[0026] The beneficial effects of the above technical solution are: the non-collinear sampling point layout fully captures the beam transmission state, the time-division multiplexing synchronization mechanism ensures the consistency of data timing, the homogeneous coordinate transformation accurately calculates the spatial offset, the synthesis processing takes into account both angle and position deviations, and the normalized distribution deviation and surface integral difference are used to evaluate energy uniformity, thereby improving the accuracy of offset and dispersion calculation.

[0027] In some embodiments of this application, the energy density dispersion is calculated based on the normalized distribution deviation of the peak power density at each sampling point and the surface integral difference of the effective radius of action, including: The peak power density at each sampling point is fitted with a fundamental Gaussian distribution to obtain the root mean square error between the actual distribution function and the theoretical distribution function. Calculate the two-dimensional integral value of the power density within the effective radius of each sampling point, and determine the relative deviation rate between the maximum and minimum integral values ​​among all sampling points; The weighted sum of the root mean square error values ​​is nonlinearly coupled with the relative deviation rate to output the energy density dispersion, wherein the weighting coefficients are dynamically adjusted according to the spatial angle.

[0028] In this embodiment, the least squares method is used for fitting the fundamental mode Gaussian distribution. The measured peak power density decay curve with radius is compared with the theoretical Gaussian curve. The theoretical curve formula is determined by the laser calibration parameters. The root mean square error is calculated by taking the square root of the square of the difference between the measured and theoretical values ​​at each radius. For example, if the measured decay is faster than the theoretical decay, the error value is 0.15, indicating that the beam quality deviates from the ideal state. The two-dimensional integral value is obtained by numerically integrating the power density distribution within the effective radius. The integral value at sampling point 1 is 38 W, at sampling point 2 it is 35 W, and at sampling point 3 it is 32 W. The difference between the maximum value of 38 W and the minimum value of 32 W is 6 W, and the relative deviation rate is 6 ÷ 38 ≈ 0.158. The dynamic adjustment rule for the weighting coefficients is as follows: when the angle is less than 1 degree, the root mean square error weight is 0.3 and the relative deviation rate weight is 0.7; when the angle is 1 to 2 degrees, the error weight is 0.4 and the deviation rate weight is 0.6; when the angle is greater than 2 degrees, the error weight is 0.5 and the deviation rate weight is 0.5, reflecting that the larger the angle, the more sensitive the beam quality is to the offset. The nonlinear coupling operation adopts a product form. The energy density dispersion is equal to the weighted sum of the root mean square error values ​​multiplied by the square root of the relative deviation rate. For example, the weighted sum of error values ​​is 0.15 × 0.4 = 0.06, the square root of the deviation rate 0.158 is approximately 0.397, and the dispersion is 0.06 × 0.397 ≈ 0.024. The smaller this value, the better the energy concentration.

[0029] The beneficial effects of the above technical solution are: Gaussian distribution fitting quantifies the degree of deviation of beam quality from the ideal, two-dimensional integral value comprehensively evaluates energy distribution, relative deviation rate reflects the consistency between sampling points, dynamic weighting coefficient is adaptively adjusted according to the included angle, and nonlinear coupling integrates the two indicators, thereby improving the accuracy and physical meaning of energy density dispersion assessment.

[0030] In some embodiments of this application, a dynamic response function of optical power-calibration depth is constructed based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value, including: Based on the thermal expansion characteristic curve of the optical lens of the laser processing system, a lookup table of focal length compensation coefficients under the current ambient temperature is established. Obtain material removal depth samples corresponding to different output power values ​​from historical processing data, and obtain the baseline response curve by fitting the least squares method. The energy density dispersion is introduced as a correction factor into the baseline response curve to construct a three-dimensional response surface that includes the focal length compensation coefficient independent variable, the real-time output power value dependent variable, and the calibration depth output. The dynamic response function is extracted by performing a differential operation along the power value dimension on the three-dimensional response surface.

[0031] In this embodiment, the lookup table uses ambient temperature as the index. Ambient temperature values ​​are collected in real time by a temperature sensor; for example, if the current temperature is 28 degrees Celsius, the lookup table yields a focal length compensation coefficient of 1.02. Historical processing data is collected from the most recent 1000 cutting records, extracting data pairs corresponding to power values ​​and material removal depths. The power range is 500 to 3000 watts, and the depth range is 0.5 to 5 millimeters. The least squares fitting method yields a baseline response curve that is a monotonically increasing curve, reflecting that higher power results in deeper material removal. Energy density dispersion is introduced as a correction factor; a dispersion value of 0.024 results in a correction coefficient of 0.98, indicating that energy dispersion causes the actual depth to be lower than the theoretical value. The three-dimensional response surface is constructed with the focal length compensation coefficient as the x-axis, the power value as the y-axis, and the calibration depth as the z-axis. For example, a focal length compensation of 1.02, a power of 2000 watts, and a depth of 2.1 millimeters after dispersion correction correspond to a point on the surface. Differential operation along the power dimension calculates the rate of change of depth with power at a fixed focal length, i.e., the response slope. This slope function is extracted as the dynamic response function to describe the sensitivity change law of power adjustment.

[0032] The expression for the dynamic response function is as follows: dD / dP = D / P, dD / dP are the dynamic response functions, D is the calibration depth, and P is the real-time output power value. D / P is the partial derivative of the calibration depth with respect to the real-time output power value.

[0033] The beneficial effects of the above technical solution are: the thermal expansion characteristic curve and lookup table realize accurate compensation for focal length drift; historical data fitting provides a benchmark response relationship; energy density dispersion correction eliminates the influence of beam quality; three-dimensional response surface integrates multiple factors; differential extraction obtains the dynamic sensitivity function; and a comprehensive and accurate power-depth response model is constructed.

[0034] In some embodiments of this application, based on the rate of change of the response slope of the dynamic response function, an adaptation weight matrix between each output power level and the transmission path offset is calculated, including: The real-time output power value is divided into N discrete gear intervals, and the ratio of the first derivative to the second derivative of the dynamic response function is calculated for each gear interval. The ratio is mapped to a preset stability evaluation interval to generate initial weight values ​​for each gear interval; Based on the direction vector of the transmission path offset, the initial weight value of each gear interval is spatially projected and corrected. The weight value is attenuated when the orthogonality between the offset direction and the power adjustment direction increases. The corrected weight values ​​are used to construct a two-dimensional matrix according to the gear range and the offset magnitude. After normalization, the adaptation weight matrix is ​​obtained.

[0035] In this embodiment, the output power levels are divided into 10 levels, such as 0-600 watts, 600-1200 watts, and up to 5400-6000 watts. The dynamic response function is calculated by numerical differentiation to obtain the first derivative (slope) and the second derivative (curvature). For example, for the 2000-watt level, the first derivative is 0.003 mm / watt and the second derivative is 0.00001 mm / watt, with a ratio of 0.00001 ÷ 0.003 ≈ 0.0033. The stability evaluation range is set to 0 to 0.01. The smaller the ratio, the more linear and stable the response. The mapping rule is linear mapping, with a ratio of 0 corresponding to a weight of 1.0 and a ratio of 0.01 corresponding to a weight of 0.5. Therefore, 0.0033 maps to an initial weight value of approximately 0.67. The transmission path offset direction vector is calculated using the method described in claim 2. For example, the direction vector is (0.3, 0.2), and the power adjustment direction is the power increase vector (0, 0, 1). The orthogonality between the two is evaluated using the cross product magnitude; the larger the cross product magnitude, the stronger the orthogonality. The projection correction rule is: for every 10% increase in orthogonality, the weight decreases by 5%. For example, for a 20% increase in orthogonality, the weight decreases from 0.67 to 0.67 × (1 - 0.1) = 0.603. The offset magnitude is divided into 5 intervals, such as 0-0.5 mm, 0.5-1.0 mm, etc., constructing a 10-level × 5-interval two-dimensional matrix. The matrix element values ​​are the corrected weights for the corresponding level and interval. Normalization ensures that the sum of the weights in each row is 1, and the sum of the weights in each column is also 1, forming an adaptation weight matrix used to guide the selection of the optimal power level under different offsets.

[0036] The beneficial effects of the above technical solution are: power level division enables power discretization analysis, derivative ratio quantifies response stability, stability mapping transforms technical indicators into weights, spatial projection correction considers the influence of offset direction, two-dimensional matrix construction provides structured weight allocation, normalization processing ensures the consistency of the weight system, and achieves optimal matching between offset and power level.

[0037] In some embodiments of this application, based on the convergence characteristics of the adaptation weight matrix, multi-band coordinated adjustment of the output power of the beam emission source is performed, including: Extract the eigenvalue sequence of the adaptation weight matrix. When the difference between the largest eigenvalue and the second largest eigenvalue exceeds a preset separation threshold, it is determined to be a single-mode dominant convergence mode, and a fast coarse adjustment strategy is executed. When all feature values ​​are distributed within a preset band interval, it is determined to be a multi-mode coupling convergence mode, and a refined collaborative adjustment strategy is initiated. The refined collaborative adjustment strategy includes superposition modulation of high-frequency power jitter components and low-frequency trend components. Based on the spectral distribution of the convergence characteristics, the power adjustment ratio of the coarse adjustment channel and the fine adjustment channel is automatically allocated, wherein the coarse adjustment channel acts on the pump current of the solid-state laser, and the fine adjustment channel acts on the diffraction efficiency of the acousto-optic modulator.

[0038] In this embodiment, eigenvalue extraction is achieved by performing singular value decomposition on the adaptation weight matrix. Assuming the matrix is ​​10×5, five eigenvalues ​​are obtained after decomposition, such as 4.2, 1.5, 0.8, 0.3, and 0.1. A preset separation threshold is set to 2.0. The difference between the largest eigenvalue (4.2) and the second largest (1.5) is 2.7, exceeding the threshold. This is considered single-mode dominant convergence, indicating that the system is primarily dominated by a single offset mode. The fast coarse-adjustment strategy directly outputs the power setting corresponding to the largest eigenvalue, for example, for the 3000-watt setting, achieved by adjusting the pump current from 20 amps to 25 amps. The bandgap is set from 0.5 to 2.0. If the eigenvalues ​​are 1.8, 1.6, 1.5, 1.4, and 1.3, all falling within this bandgap, it is considered multi-mode coupled convergence, indicating the coexistence of multiple offset modes. The refined collaborative adjustment strategy decomposes the power adjustment into a low-frequency trend component (below 1 Hz) and a high-frequency jitter component (10 to 100 Hz). The trend component is achieved by slow adjustment of the pump current, while the jitter component is achieved by rapid switching of the acousto-optic modulator. The two are superimposed on the output. The amplitude ratio of the coarse adjustment channel and the fine adjustment channel is allocated according to the dispersion of the eigenvalues. The more dispersed the eigenvalues, the higher the proportion of coarse adjustment; for example, when single-mode is dominant, coarse adjustment accounts for 80%. The more concentrated the eigenvalues, the higher the proportion of fine adjustment; for example, when multi-mode is coupled, coarse adjustment accounts for 40% and fine adjustment accounts for 60%. This collaborative mechanism balances adjustment speed and accuracy.

[0039] The beneficial effects of the above technical solutions are: eigenvalue analysis reveals the essence of the convergence mode; single-mode coarse adjustment provides a fast response to dominate the offset; multi-mode collaborative adjustment finely processes complex offsets; superposition of high and low frequency components achieves a combination of fast and slow modes; automatic allocation of channel amplitude ratio optimizes adjustment resources; and coarse and fine dual-channel hardware collaboration improves the dynamic performance of the system.

[0040] In some embodiments of this application, after initiating the refined collaborative adjustment strategy, the method further includes: Acquire the laser medium temperature field distribution data and the cavity length drift of the beam emission source; The focal position shift caused by the thermal lensing effect is calculated based on the temperature field distribution data, and a first compensation power value is generated. The power fluctuation caused by longitudinal mode competition is calculated based on the cavity length drift, and a second compensation power value is generated. The first compensation power value and the second compensation power value are vector synthesized to obtain the environmental disturbance feedforward compensation amount, which is then superimposed on the output of the refined collaborative adjustment strategy.

[0041] In this embodiment, the laser medium is ytterbium-doped double-clad fiber. Temperature field distribution data is collected by distributed fiber optic grating sensors on the fiber cladding surface, with 10 temperature measurement points arranged along the fiber length. The measured temperature gradient is, for example, 25 to 35 degrees Celsius. The change in focal length of the thermal lens is calculated using the thermo-optic coefficient. A 10-degree Celsius increase in temperature causes a change in refractive index, resulting in a 0.3 mm shortening of the equivalent focal length and a 0.3 mm shift in the focal position. To compensate for this shift, a 2% increase in power is required, i.e., the first compensation power value is 2% of the current power. The cavity length drift is measured by a piezoelectric ceramic displacement sensor on the back of the cavity mirror. For example, a 0.01 mm change in cavity length causes a change in the longitudinal mode spacing, resulting in a power fluctuation of approximately 1.5%. The second compensation power value is obtained by looking up a table; a 0.01 mm change in cavity length corresponds to a compensation power of 1.5%. Vector synthesis superimposes the first compensation value (2%) and the second compensation value (1.5%) in the direction of power increase. Since both act in the power increase direction, they are directly added to obtain the environmental disturbance feedforward compensation amount of 3.5%. This compensation is added to the output of the refined coordinated adjustment strategy. For example, if the original strategy outputs 2500 watts, the actual output after compensation is 2587.5 watts. This feedforward mechanism compensates for the impact of environmental disturbances in advance, improving the system's anti-interference capability.

[0042] The beneficial effects of the above technical solution are: real-time monitoring of thermal effects using temperature field data, accurate quantification of focus shift using thermal lens calculation, detection of cavity length drift revealing longitudinal mode competition, dual compensation power values ​​to address thermal and optical disturbances respectively, vector synthesis to fully cover environmental disturbances, and feedforward superposition to suppress interference in advance, significantly improving system stability and processing consistency.

[0043] In some embodiments of this application, after multi-band coordinated adjustment of the output power of the beam emission source based on the convergence characteristics of the adaptation weight matrix, the method further includes: Establish a trajectory database of the output power adjustment amount and the transmission path offset, the trajectory database recording parameter pairs before and after each adjustment; A long short-term memory network is used to perform time-series modeling on the change trajectory database to predict the optimal power pre-regulation amount within a specific future time window.

[0044] In some embodiments of this application, after multi-band coordinated adjustment of the output power of the beam emission source based on the convergence characteristics of the adaptation weight matrix, the method further includes: When the prediction confidence exceeds the preset confidence threshold, a preset proportion of the optimal power pre-adjustment amount is injected in advance at the current moment as a feedforward control amount, and the remaining proportion is dynamically corrected by real-time feedback control.

[0045] In this embodiment, the change trajectory database records the most recent 1000 adjustment events. Each record contains three parameters: the pre-adjustment offset, the adjustment amount, and the post-adjustment offset, for example (0.8 mm, +300 watts, 0.3 mm). The input sequence of the Long Short-Term Memory (LSTM) network is the past 50 adjustment events, and the output is the optimal power adjustment amount within the next 10 event windows. The network hidden layer is set to 128 neurons, the learning rate is 0.001, and the training iterations are 500. The specific time window is set to 5 seconds to predict the optimal adjustment amount within the next 5 seconds. The prediction confidence is the probability value of the network output, for example, 0.87. The preset confidence threshold is set to 0.80. When the confidence exceeds the threshold, feedforward control is triggered. The optimal power pre-adjustment amount is, for example, +200 watts, and the preset ratio is set to 70%, that is, 140 watts are injected in advance as feedforward at the current moment, and the remaining 30% (60 watts) is dynamically adjusted by real-time feedback control according to the actual offset changes. This predictive feedforward mechanism utilizes historical data patterns to anticipate upcoming shifts, reducing feedback lag and enhancing the system's forward-looking capabilities.

[0046] The beneficial effects of the above technical solution are: the trajectory database accumulates adjustment experience data, the LSTM network mines time-series dependency patterns, the optimal adjustment amount is predicted to achieve proactive control, the confidence threshold ensures the reliability of prediction, the preset ratio injection balances prediction and real-time feedback, and the feedforward control effectively compensates for system lag, thereby improving the dynamic response speed and accuracy.

[0047] To further illustrate the technical concept of this invention, the technical solution of this invention will now be described in conjunction with specific application scenarios.

[0048] Correspondingly, such as Figure 2 As shown, this application also provides a laser calibration system, including: The parameter acquisition module is used to acquire the real-time output power value of the beam emission source in the laser processing system and the set of light spot morphology parameters acting on the workpiece surface; The first calculation module is used to calculate the transmission path offset and energy density dispersion of the light beam based on the spatial vector difference of the light spot morphology parameter set at different spatial sampling points. The function construction module is used to construct a dynamic response function of optical power-calibration depth based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value. The second calculation module is used to calculate the adaptation weight matrix between each output power level and the transmission path offset based on the rate of change of the response slope of the dynamic response function. The laser calibration module is used to perform multi-band coordinated adjustment of the output power of the beam emission source based on the convergence characteristics of the adaptation weight matrix, thereby realizing laser calibration control.

[0049] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0050] Although the invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. The fact that not all of these combinations are described in this specification is merely for the sake of brevity and resource conservation.

[0051] It will be understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser calibration method, characterized in that, include: Acquire the real-time output power value of the beam emission source in the laser processing system and the set of beam spot morphology parameters acting on the workpiece surface; Based on the spatial vector differences of the light spot morphology parameter set at different spatial sampling points, the transmission path offset and energy density dispersion of the light beam are calculated. Based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value, a dynamic response function of optical power-calibration depth is constructed. Based on the rate of change of the response slope of the dynamic response function, the adaptation weight matrix between each output power level and the transmission path offset is calculated. Based on the convergence characteristics of the adaptation weight matrix, the output power of the beam emission source is adjusted in a multi-band coordinated manner to achieve laser calibration control.

2. The laser calibration method according to claim 1, characterized in that, Based on the spatial vector differences of the light spot morphology parameter sets at different spatial sampling points, the propagation path offset and energy density dispersion of the light beam are calculated, including: The beam morphology parameter set is simultaneously captured at at least three non-collinear spatial sampling points using a preset beam quality analyzer. The beam morphology parameter set includes the beam center coordinates, ellipticity, peak power density, and effective radius. Based on the homogeneous coordinate transformation of the center coordinates of the light spot at each sampling point, the spatial angle and translation vector between the actual optical axis of the beam and the reference optical axis are calculated, and the spatial angle and the translation vector are combined to form the transmission path offset. The energy density dispersion is calculated based on the normalized distribution deviation of the peak power density at each sampling point and the surface integral difference of the effective radius.

3. The laser calibration method according to claim 2, characterized in that, Based on the normalized distribution deviation of the peak power density at each sampling point and the surface integral difference of the effective radius, the energy density dispersion is calculated, including: The peak power density at each sampling point is fitted with a fundamental Gaussian distribution to obtain the root mean square error between the actual distribution function and the theoretical distribution function. Calculate the two-dimensional integral value of the power density within the effective radius of each sampling point, and determine the relative deviation rate between the maximum and minimum integral values ​​among all sampling points; The weighted sum of the root mean square error values ​​is nonlinearly coupled with the relative deviation rate to output the energy density dispersion, wherein the weighting coefficients are dynamically adjusted according to the spatial angle.

4. The laser calibration method according to claim 1, characterized in that, Based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value, a dynamic response function of optical power-calibration depth is constructed, including: Based on the thermal expansion characteristic curve of the optical lens of the laser processing system, a lookup table of focal length compensation coefficients under the current ambient temperature is established. Obtain material removal depth samples corresponding to different output power values ​​from historical processing data, and obtain the baseline response curve by fitting the least squares method. The energy density dispersion is introduced as a correction factor into the baseline response curve to construct a three-dimensional response surface that includes the focal length compensation coefficient independent variable, the real-time output power value dependent variable, and the calibration depth output. The dynamic response function is extracted by performing a differential operation along the power value dimension on the three-dimensional response surface.

5. The laser calibration method according to claim 1, characterized in that, Based on the rate of change of the response slope of the dynamic response function, the adaptation weight matrix between each output power level and the transmission path offset is calculated, including: The real-time output power value is divided into N discrete gear intervals, and the ratio of the first derivative to the second derivative of the dynamic response function is calculated for each gear interval. The ratio is mapped to a preset stability evaluation interval to generate initial weight values ​​for each gear interval; Based on the direction vector of the transmission path offset, the initial weight value of each gear interval is spatially projected and corrected. The weight value is attenuated when the orthogonality between the offset direction and the power adjustment direction increases. The corrected weight values ​​are used to construct a two-dimensional matrix according to the gear range and the offset magnitude. After normalization, the adaptation weight matrix is ​​obtained.

6. The laser calibration method according to claim 1, characterized in that, Based on the convergence characteristics of the adaptation weight matrix, the output power of the beam emission source is adjusted in a multi-band coordinated manner, including: Extract the eigenvalue sequence of the adaptation weight matrix. When the difference between the largest eigenvalue and the second largest eigenvalue exceeds a preset separation threshold, it is determined to be a single-mode dominant convergence mode, and a fast coarse adjustment strategy is executed. When all feature values ​​are distributed within a preset band interval, it is determined to be a multi-mode coupling convergence mode, and a refined collaborative adjustment strategy is initiated. The refined collaborative adjustment strategy includes superposition modulation of high-frequency power jitter components and low-frequency trend components. Based on the spectral distribution of the convergence characteristics, the power adjustment ratio of the coarse adjustment channel and the fine adjustment channel is automatically allocated, wherein the coarse adjustment channel acts on the pump current of the solid-state laser, and the fine adjustment channel acts on the diffraction efficiency of the acousto-optic modulator.

7. The laser calibration method according to claim 6, characterized in that, After initiating the refined coordinated adjustment strategy, it also includes: Acquire the laser medium temperature field distribution data and the cavity length drift of the beam emission source; The focal position shift caused by the thermal lensing effect is calculated based on the temperature field distribution data, and a first compensation power value is generated. The power fluctuation caused by longitudinal mode competition is calculated based on the cavity length drift, and a second compensation power value is generated. The first compensation power value and the second compensation power value are vector synthesized to obtain the environmental disturbance feedforward compensation amount, which is then superimposed on the output of the refined collaborative adjustment strategy.

8. The laser calibration method according to claim 1, characterized in that, Based on the convergence characteristics of the adaptation weight matrix, after multi-band coordinated adjustment of the output power of the beam emission source, the method further includes: Establish a trajectory database of the output power adjustment amount and the transmission path offset, the trajectory database recording parameter pairs before and after each adjustment; A long short-term memory network is used to perform time-series modeling on the change trajectory database to predict the optimal power pre-regulation amount within a specific future time window.

9. The laser calibration method according to claim 8, characterized in that, Based on the convergence characteristics of the adaptation weight matrix, after multi-band coordinated adjustment of the output power of the beam emission source, the method further includes: When the prediction confidence exceeds the preset confidence threshold, a preset proportion of the optimal power pre-adjustment amount is injected in advance at the current moment as a feedforward control amount, and the remaining proportion is dynamically corrected by real-time feedback control.

10. A laser calibration system, applied to the laser calibration method as described in any one of claims 1-9, characterized in that, include: The parameter acquisition module is used to acquire the real-time output power value of the beam emission source in the laser processing system and the set of light spot morphology parameters acting on the workpiece surface; The first calculation module is used to calculate the transmission path offset and energy density dispersion of the light beam based on the spatial vector difference of the light spot morphology parameter set at different spatial sampling points. The function construction module is used to construct a dynamic response function of optical power-calibration depth based on the energy density dispersion, the focal length compensation coefficient of the beam, and the real-time output power value. The second calculation module is used to calculate the adaptation weight matrix between each output power level and the transmission path offset based on the rate of change of the response slope of the dynamic response function. The laser calibration module is used to perform multi-band coordinated adjustment of the output power of the beam emission source based on the convergence characteristics of the adaptation weight matrix, thereby realizing laser calibration control.

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