Cutting head vibration online detection method and system for laser cutting equipment

Abstract

The application provides a cutting head vibration online detection method and system for a laser cutting device, relates to the technical field of device detection, and the method comprises the following steps: in a laser processing process, a wavefront aberration signal of processing laser is synchronously collected and separated in real time, multi-dimensional vibration modal parameters of the cutting head are calculated based on periodic aberration disturbance components, and the health state of an optical system is evaluated based on the deviation of a slowly-varying aberration background component from a preset reference; a feedforward control signal is generated according to the multi-dimensional vibration modal parameters to generate a compensation action, and residual wavefront errors after compensation are extracted for closed-loop control, and the laser focal point position is locked at a set position on the workpiece surface in a vibration environment. The technical problems that the cutting head vibration is difficult to directly perceive, external sensors are lagged and vibration and optical degradation cannot be distinguished in the prior art are solved. Through decoupling of vibration and optical degradation on the laser processing wavefront aberration signal, the technical effect of improving the processing precision and quality of the laser device is achieved.

Description

Technical Field

[0001] This invention relates to the field of equipment testing technology, and specifically to a method and system for online detection of vibration of the cutting head in laser cutting equipment. Background Technology

[0002] Under complex processing conditions, the cutting head of existing laser cutting equipment is subject to high-frequency, multi-dimensional vibrations. These vibrations are difficult to measure directly at the end. Currently, most technologies use external accelerometers and displacement sensors to detect the vibration of the cutting head. However, these sensors are installed outside the cutting head and have inherent defects such as measurement lag and indirect detection, making it impossible to capture the vibration of the cutting head instantaneously.

[0003] Furthermore, relying on external sensors to detect cutting head vibration makes it impossible to distinguish between vibration disturbances and optical components, such as beam distortion caused by the degradation of the focusing lens itself. This can easily lead to misjudging the aging of optical components as abnormal vibration, or ignoring the impact of vibration on the optical system. As a result, it is difficult to maintain focus stability during the cutting process, causing the laser beam to drift slightly on the workpiece surface, which in turn leads to fluctuations in cutting quality, uneven cutting edges, or even processing defects.

[0004] In summary, existing technologies suffer from the problem that cutting head vibration is difficult to detect directly, external sensors are lagging and cannot distinguish between vibration and optical degradation, leading to unstable cutting quality. Summary of the Invention

[0005] The purpose of this application is to provide an online detection method and system for the vibration of the cutting head of a laser cutting equipment, in order to solve the technical problems in the prior art where the vibration of the cutting head is difficult to be directly sensed, external sensors are lagging and cannot distinguish between vibration and optical degradation, resulting in unstable cutting quality.

[0006] In view of the above problems, this application provides a method and system for online detection of vibration of the cutting head of laser cutting equipment.

[0007] The first aspect of this application provides a method for online vibration detection of a cutting head in a laser cutting equipment. The method includes: during laser processing, simultaneously acquiring wavefront aberration signals of the processing laser emitted from the laser cutting equipment; and in real time separating periodic aberration disturbance components with the same frequency as mechanical vibration and slowly varying aberration background components determined by the state of optical elements from the wavefront aberration signals; calculating multidimensional vibration mode parameters of the cutting head in space based on the periodic aberration disturbance components; simultaneously assessing the health status of the optical system and generating a health warning signal based on the deviation of the slowly varying aberration background components from a preset reference; generating a feedforward control signal based on the multidimensional vibration mode parameters to drive a beam orientation adjustment device inside the cutting head to perform a compensation action and extracting the compensated residual wavefront error; and using the compensated residual wavefront error as feedback for closed-loop control to lock the laser focus position at a set position on the workpiece surface under vibration conditions.

[0008] Optionally, the wavefront aberration signal is orthogonally decomposed to obtain a time series containing multiple basis function coefficients; the first-order aberration coefficients representing the overall tilt of the beam in the basis function coefficients are used as characteristic signals for vibration decoupling analysis; the characteristic signals are subjected to spectral analysis, and the specific frequency band energy related to the natural frequency of the cutting head's mechanical structure in the spectrum is reconstructed into a time-domain signal as the periodic aberration perturbation component; the periodic aberration perturbation component is filtered out from the time series of the basis function coefficients to obtain the slowly varying aberration background component.

[0009] Optionally, for at least one primary vibration mode determined by the mechanical structure of the cutting head, a correspondence model is established between the vibration direction vector of the primary vibration mode and a specific combination of basis function coefficients in the wavefront aberration signal; real-time amplitude and phase information of the specific combination of basis function coefficients are extracted from the periodic aberration perturbation components; the real-time amplitude and phase information, as well as the real-time pose information of the cutting head during processing, are input into the correspondence model to calculate the multidimensional vibration mode parameters of the cutting head under the primary vibration mode, wherein the multidimensional vibration mode parameters include at least the equivalent vibration amplitude and direction in the workpiece coordinate system.

[0010] Optionally, a standard vibration excitation matching the main vibration mode is applied to the cutting head, and a calibration wavefront aberration signal under the standard vibration excitation is acquired simultaneously; the periodic aberration perturbation component caused by the standard vibration excitation is separated from the calibration wavefront aberration signal as the calibration perturbation component; the basis function coefficients that produce a stable response to the standard vibration excitation are identified from the calibration perturbation component as a specific basis function coefficient combination, and its response amplitude and phase are recorded; based on the vibration direction vector of the standard vibration excitation and the response amplitude and phase of the specific basis function coefficient combination, the correspondence model is established.

[0011] Optionally, higher-order aberration coefficients sensitive to changes in the surface shape of optical elements and assembly errors are extracted from the slowly varying aberration background components. After the equipment has been assembled or maintained, the average value of the higher-order aberration coefficients at different output powers is recorded under constant temperature and no processing load conditions to establish a preset health benchmark. During real-time processing, the deviation of the higher-order aberration coefficients from the preset benchmark and their rate of change are monitored in real time. When the deviation of any higher-order aberration coefficient and its rate of change exceed a preset degradation judgment threshold, a health warning signal containing the specific degradation type and the estimated remaining service life is generated.

[0012] Optionally, the angular vibration component of the cutting head in the beam propagation direction is extracted from the multidimensional vibration mode parameters; the expected drift trajectory of the focal point on the workpiece surface is calculated based on the current focal position of the cutting head and the angular vibration component; the deflection amount required to reverse the beam focal position is calculated based on the expected drift trajectory; and a feedforward control signal for driving the beam orientation adjustment device is generated based on the deflection amount.

[0013] Optionally, the feedforward control signal is sent to the beam orientation adjustment device; within the same control cycle of the beam orientation adjustment device, a new wavefront aberration signal is acquired; from the new wavefront aberration signal, the aberration coefficient characterizing the residual beam pointing deviation is extracted as the residual wavefront error.

[0014] Optionally, based on the residual beam pointing deviation characterized by the residual wavefront error and the current focal position of the cutting head, the residual position deviation of the focal point on the workpiece surface is calculated; based on the residual position deviation, a feedback control signal for further correcting the beam pointing is generated; the feedback control signal is superimposed with the feedforward control signal to form a composite control command, which jointly drives the beam orientation adjustment device to suppress the residual position deviation and lock the focal point.

[0015] Optionally, the feedforward control signal and the feedback control signal are combined using frequency domain weighting, wherein the feedforward control signal is mainly used for control components above the cutoff frequency, and the feedback control signal is mainly used for control components below the cutoff frequency.

[0016] A second aspect of this application provides an online vibration detection system for a laser cutting head, the system comprising: a signal separation module, used to synchronously acquire the wavefront aberration signal of the processing laser emitted by the laser cutting equipment during laser processing, and to separate in real time the periodic aberration disturbance component with the same frequency as the mechanical vibration and the slowly varying aberration background component determined by the state of the optical elements from the wavefront aberration signal; a health status assessment module, used to calculate the multidimensional vibration mode parameters of the cutting head in space based on the periodic aberration disturbance component, and simultaneously assess the health status of the optical system and generate a health warning signal based on the deviation of the slowly varying aberration background component from a preset benchmark; a compensation drive module, used to generate a feedforward control signal based on the multidimensional vibration mode parameters, drive the beam orientation adjustment device inside the cutting head to generate a compensation action, and extract the residual wavefront error after compensation; and a closed-loop control module, used to perform closed-loop control with the compensated residual wavefront error as feedback, and lock the laser focus position at a set position on the workpiece surface under vibration conditions.

[0017] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0018] The method provided in this application synchronously acquires the wavefront aberration signal of the processing laser emitted from the laser cutting equipment during laser processing. From the wavefront aberration signal, it separates in real time a periodic aberration disturbance component with the same frequency as mechanical vibration and a slowly varying aberration background component determined by the state of optical elements. Based on the periodic aberration disturbance component, it calculates the multidimensional vibration mode parameters of the cutting head in space. Simultaneously, based on the deviation of the slowly varying aberration background component from a preset benchmark, it assesses the health status of the optical system and generates a health warning signal. According to the multidimensional vibration mode parameters, it generates a feedforward control signal to drive the beam orientation adjustment device inside the cutting head to perform a compensation action and extract the compensated residual wavefront error. Using the compensated residual wavefront error as feedback, it performs closed-loop control to lock the laser focus position at a set position on the workpiece surface under vibration conditions. This achieves the technical effect of decoupling vibration and optical degradation from the laser processing wavefront aberration signal, realizing accurate detection of cutting head vibration, optical health warning, and actively maintaining the focus on the working surface when vibration occurs, thereby improving the processing accuracy and quality of the laser equipment.

[0019] The above description is merely an overview of the technical solution of this application. To better understand the technical means of this application and to facilitate its implementation according to the description, and to make the above and other objects, features, and advantages of this application more apparent, specific embodiments of this application are described below. It should be understood that the content described in this section is not intended to identify key or important features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent through the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 A schematic flowchart illustrating the online vibration detection method for laser cutting equipment provided in this application.

[0022] Figure 2 This is a schematic diagram of the online vibration detection system for laser cutting equipment provided in this application.

[0023] Explanation of reference numerals in the attached diagram: Signal separation module 11, Health status assessment module 12, Compensation drive module 13, Closed-loop control module 14. Detailed Implementation

[0024] This application provides a method and system for online detection of cutting head vibration in laser cutting equipment. It addresses the technical problems of existing technologies, such as the difficulty in directly sensing cutting head vibration, the lag of external sensors, and the inability to distinguish between vibration and optical degradation, leading to unstable cutting quality. The method achieves the technical effect of decoupling vibration and optical degradation from the laser processing wavefront aberration signal, enabling precise detection of cutting head vibration, optical health early warning, and actively maintaining the focus on the working surface when vibration occurs, thereby improving the processing accuracy and quality of laser cutting equipment.

[0025] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be understood that the present invention is not limited to the exemplary embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. It should also be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all of them.

[0026] Example 1, as Figure 1 As shown, this application provides an online vibration detection method for a cutting head of a laser cutting equipment, the online vibration detection method for a cutting head of a laser cutting equipment includes: During laser processing, the wavefront aberration signal of the processing laser emitted by the laser cutting equipment is acquired synchronously, and the periodic aberration disturbance component with the same frequency as the mechanical vibration and the slowly varying aberration background component determined by the state of the optical elements are separated from the wavefront aberration signal in real time.

[0027] Furthermore, from the wavefront aberration signal, the periodic aberration disturbance component with the same frequency as the mechanical vibration and the slowly varying aberration background component determined by the optical element state are separated in real time, including: performing orthogonal decomposition on the wavefront aberration signal to obtain a time series containing multiple basis function coefficients; using the first-order aberration coefficients representing the overall tilt of the beam in the basis function coefficients as the characteristic signal for vibration decoupling analysis; performing spectral analysis on the characteristic signal to reconstruct the specific frequency band energy related to the natural frequency of the cutting head's mechanical structure in the spectrum into a time-domain signal as the periodic aberration disturbance component; and filtering out the periodic aberration disturbance component from the time series of the basis function coefficients to obtain the slowly varying aberration background component.

[0028] Specifically, during laser processing, a wavefront sensor synchronously acquires the wavefront aberration signal of the laser beam emitted from the equipment. This wavefront aberration signal refers to the deviation between the actual wavefront and the ideal wavefront of the laser beam. The wavefront sensor is installed inside the cutting head or on the beam output path, acquiring a portion of the laser beam being processed through a beam splitter or reflector without affecting the output of the main cutting beam. The sampling frequency of the wavefront sensor is set to be more than twice the vibration frequency of the laser cutting head to satisfy the Nyquist sampling theorem and ensure accurate separation of the vibration components. For example, if the natural vibration frequency of the cutting head is 500Hz, the wavefront sampling frequency is set to at least 1kHz.

[0029] The Zernike orthogonal polynomial decomposition method is used to orthogonally decompose the acquired wavefront aberration signal into a set of independent basis functions. The order of the basis functions is set from 3 to 20 according to the detection accuracy requirements, resulting in a time series containing multiple basis function coefficients. Each basis function coefficient corresponds to a specific type of aberration. The first-order aberration coefficient represents the overall tilt state of the beam, while the second-order and higher aberration coefficients correspond to complex forms such as focusing, defocusing, or aberration.

[0030] The first-order aberration coefficients, representing the overall tilt of the beam, are used as characteristic signals for vibration decoupling analysis. These characteristic signals are then subjected to spectral analysis using Fast Fourier Transform (IFFT). The natural frequencies of the cutting head's mechanical structure, such as 50Hz and 120Hz, are obtained through equipment calibration. These natural frequencies are determined by the structural characteristics of the cutting head frame, motor, and transmission mechanism. The calibration method involves applying standard vibration excitation to the cutting head, acquiring the corresponding wavefront aberration signals, and extracting the characteristic frequencies. The Inverse Fourier Transform (IFFT) algorithm is then used to reconstruct the energy of the frequency band corresponding to these natural frequencies in the time domain, yielding periodic aberration perturbation components. These periodic aberration perturbation components are at the same frequency as the mechanical vibration of the cutting head, reflecting the wavefront deviation caused by the mechanical vibration.

[0031] An adaptive filtering algorithm, such as Kalman filtering, is used. The filtering coefficients are adjusted in real time according to the processing conditions. The periodic aberration disturbance components are filtered out from the time series of the basis function coefficients to obtain the slowly varying aberration background components. The slowly varying aberration background components are not affected by mechanical vibration and are determined only by the state changes of the optical elements.

[0032] For example, analyzing a 1064nm fiber laser cutting device, a Shack-Hartmann wavefront sensor was used to acquire wavefront aberration signals at a frequency of 2000Hz during the processing. This wavefront aberration signal was then subjected to Zernike orthogonal decomposition of order 15, yielding a time series containing 15 basis function coefficients. The time series of the first-order tilt aberration coefficients Z1 and Z2 showed significant fluctuations. FFT spectral analysis identified the natural frequency of the cutting head's mechanical structure as 50Hz. Energy in the 48Hz-52Hz frequency band was extracted and reconstructed using IFFT to obtain periodic aberration perturbation components, with amplitude fluctuations ranging from 0.05λ to 0.2λ. Kalman filtering with a filter coefficient of 0.02 was then used to remove the periodic aberration perturbation components, resulting in a slowly varying aberration background component with an amplitude change rate of 0.03λ / h. This corresponds to the slow degradation of the focusing mirror shape and is unrelated to the vibration signal, achieving effective separation of the two types of signals.

[0033] By decoupling the rapid periodic errors caused by mechanical vibration in laser processing from the slow-varying errors of the optical system, the accuracy of subsequent vibration detection and the reliability of optical health assessment are ensured, thereby improving the precision and stability of laser processing.

[0034] Based on the periodic aberration perturbation components, the multidimensional vibration mode parameters of the cutting head in space are calculated. At the same time, based on the deviation of the slowly varying aberration background components from the preset benchmark, the health status of the optical system is evaluated and a health warning signal is generated.

[0035] Furthermore, based on the periodic aberration perturbation components, the multidimensional vibration mode parameters of the cutting head in space are calculated, including: for at least one principal vibration mode determined by the mechanical structure of the cutting head, establishing a correspondence model between the vibration direction vector of the principal vibration mode and a specific combination of basis function coefficients in the wavefront aberration signal; extracting the real-time amplitude and phase information of the specific basis function coefficient combination from the periodic aberration perturbation components; inputting the real-time amplitude and phase information, as well as the real-time pose information of the cutting head during processing, into the correspondence model to calculate the multidimensional vibration mode parameters of the cutting head under the principal vibration mode, wherein the multidimensional vibration mode parameters include at least the equivalent vibration amplitude and direction in the workpiece coordinate system.

[0036] Specifically, a vibration mode refers to the inherent vibration pattern of a mechanical structure at a specific frequency. Each mode can be described by a vibration direction vector in terms of its spatial vibration direction and by a vibration amplitude in terms of its magnitude. Based on the mechanical structural information of the cutting head, such as the cutting head arm length, transmission components, and focusing lens mount, a correspondence model is established between the vibration direction vector of at least one principal vibration mode and a specific combination of basis function coefficients in the wavefront aberration signal. The specific combination of basis function coefficients refers to the combination of coefficients corresponding to the vibration characteristics of the cutting head in orthogonal decomposition.

[0037] From the periodic aberration perturbation components, real-time amplitude and phase information of specific basis function coefficient combinations are extracted. The amplitude represents the instantaneous magnitude of the wavefront deviation, and the phase represents the instantaneous state of vibration, equivalent to the position angle of the cutting head during the vibration period. Simultaneously, pose sensors, such as laser displacement sensors and gyroscopes, collect real-time pose information of the cutting head in the workpiece coordinate system during processing, including the X, Y, and Z axis coordinates and rotation angles around these axes. The sampling frequency must be synchronized with the wavefront sampling frequency. This real-time pose information is used to correct spatial coordinate system deviations of the vibration parameters, ensuring that the calculation results accurately correspond to the workpiece processing position. The workpiece coordinate system refers to a three-dimensional coordinate system established with the workpiece as a reference. Typically, the X, Y, and Z axes are fixed on the workpiece surface or clamping position, used to describe the spatial motion of the cutting head relative to the workpiece.

[0038] The extracted real-time amplitude, phase, and pose information are input into the established correspondence model. Through a solution algorithm, the multidimensional vibration modal parameters of the cutting head under the main vibration modes are obtained. For example, using least-squares fitting, the real-time amplitude and phase of specific basis function coefficient combinations extracted from the periodic aberration perturbation components are transformed into instantaneous wavefront offset vectors. The wavefront perturbation of each basis function is represented as the amplitude multiplied by a phase cosine function. Simultaneously, the real-time pose information of the cutting head during processing, including its three-dimensional position and rotation angles around the three axes, is integrated into a spatial coordinate vector.

[0039] Based on the established correspondence model between vibration modes and wavefront coefficient combinations, a sensitivity matrix equation is established by combining the spatial direction vector of each principal vibration mode with the coefficients of a specific wavefront basis function. This sensitivity matrix equation describes the projection coefficients of the vibration onto the wavefront aberration in the spatial direction. Substituting the instantaneous wavefront offset vector and the cutting head pose vector into this sensitivity matrix equation, the amplitude and direction of each vibration mode at a given time point are solved using a least-squares fitting algorithm. This yields the real-time vibration amplitude and direction vector of each principal vibration mode in the workpiece coordinate system, achieving accurate mapping from optical wavefront disturbance signals to multi-dimensional vibration mode parameters of the cutting head. These multi-dimensional vibration mode parameters include at least the equivalent vibration amplitude and vibration direction in the workpiece coordinate system. The equivalent vibration amplitude refers to the actual magnitude of the vibration's impact after projection onto the machining surface, and the vibration direction characterizes the vector direction of the vibration in three-dimensional space, used for machining error prediction and dynamic compensation.

[0040] By converting wavefront aberration signals into cutting head vibration parameters, the cutting head vibration can be quantified in the workpiece coordinate system, providing basic data for real-time vibration suppression, processing path adjustment, or error compensation, thereby improving the accuracy and quality of laser processing.

[0041] Furthermore, establishing a correspondence model between the vibration direction vector of the main vibration mode and a specific combination of basis function coefficients in the wavefront aberration signal includes: applying a standard vibration excitation matching the main vibration mode to the cutting head, and simultaneously acquiring a calibrated wavefront aberration signal under the standard vibration excitation; separating the periodic aberration perturbation component caused by the standard vibration excitation from the calibrated wavefront aberration signal as the calibrated perturbation component; identifying the basis function coefficients that produce a stable response to the standard vibration excitation from the calibrated perturbation component as a specific combination of basis function coefficients, and recording its response amplitude and phase; and establishing the correspondence model based on the vibration direction vector of the standard vibration excitation and the response amplitude and phase of the specific combination of basis function coefficients.

[0042] Specifically, a standard vibration excitation matching the characteristics of the main vibration mode is applied to the cutting head, that is, simulating the typical motion of the main vibration mode in terms of vibration frequency, amplitude, and direction. The standard vibration excitation refers to an external drive capable of generating a repeatable and quantifiable response on the cutting head structure. For example, sinusoidal vibration is applied using a precision vibration table or a servo-driven piezoelectric actuator, with the excitation direction consistent with the vibration direction vector of the main vibration mode and the frequency consistent with the natural frequency of the main mode. Simultaneously with the application of the standard vibration excitation, a calibration wavefront aberration signal from the laser emission is synchronously acquired using a wavefront sensor. Using the same signal separation method as in real-time processing, the calibration wavefront aberration signal is orthogonally decomposed, followed by spectral analysis and filtering. The periodic aberration disturbance component caused by the standard vibration excitation is separated from the calibration wavefront aberration signal and used as the calibration disturbance component.

[0043] By analyzing the spectral and time-domain characteristics of the calibration disturbance components, the basis function coefficients that produce a stable response to standard vibration excitation are identified. The criteria for determining a stable response are that the fluctuation frequency of the basis function coefficient is consistent with the standard vibration excitation frequency and the response amplitude variation coefficient is less than or equal to 5%. The response amplitude variation coefficient is used to measure the stability of the response amplitude of a specific basis function coefficient to standard vibration excitation. It is obtained by calculating the ratio of the standard deviation to the average value of the amplitude of the basis function coefficient within the calibration period to ensure the stability and repeatability of the response. The basis function coefficients that meet the criteria are combined into specific basis function coefficient combinations, and the response amplitude and phase information of each specific basis function coefficient under calibration vibration are recorded.

[0044] By associating the known vibration direction vector of a standard vibration excitation with the response amplitude and phase of a specific combination of basis function coefficients, a correspondence model is established. For example, a correspondence model of the principal vibration modes can be established by constructing a sensitivity matrix, and the response amplitude and phase can be combined into a response vector C. j Each element corresponds to a selected specific basis function coefficient, reflecting the projection of the vibration mode onto each basis function. Then, the vibration direction vector v is represented by a sensitivity matrix S. j With response vector C j The correlation is established where each column of the sensitivity matrix corresponds to a basis function coefficient, and each row corresponds to the projection coefficients of the vibration space direction, forming a matrix relationship. By calibrating multiple sets of standard vibration excitations in different directions, the equation can be solved using least squares fitting or matrix inversion methods to obtain the sensitivity matrix S. Its elements represent the projection ratio of vibration in each spatial direction to each basis function coefficient, thus completing the mapping from the spatial vibration direction of the cutting head to the wavefront basis function response.

[0045] By standard vibration calibration, a precise mapping is established between the modal information of mechanical vibration in the cutting head space and the optical wavefront disturbance signal. This allows for the deduction of multidimensional vibration modal parameters of the cutting head in the workpiece coordinate system from the real-time wavefront signal, providing a reliable basis for vibration compensation and machining accuracy optimization.

[0046] Furthermore, based on the deviation of the gradually varying aberration background component from a preset benchmark, the health status of the optical system is assessed and a health warning signal is generated. This includes: extracting higher-order aberration coefficients from the gradually varying aberration background component that are sensitive to changes in the surface shape of optical elements and assembly errors; after the equipment has been assembled or maintained, recording the average value of the higher-order aberration coefficients at different output powers under constant temperature and no processing load conditions to establish a preset health benchmark; during real-time processing, monitoring the deviation of the higher-order aberration coefficients from the preset benchmark and their rate of change in real time; when the combination of the deviation of any higher-order aberration coefficient and its rate of change exceeds a preset degradation judgment threshold, generating a health warning signal that includes the specific degradation type and the estimated remaining service life.

[0047] Specifically, higher-order aberration coefficients, namely third-order and above Zernike coefficients, are extracted from the slowly varying aberration background components. These higher-order aberration coefficients are extremely sensitive to minute surface deformations of optical components, lens eccentricity, or assembly errors, and are unaffected by vibration-related lower-order aberrations such as overall beam tilt. After the laser cutting equipment is assembled and debugged, and optical calibration or lens replacement and maintenance are completed, under constant temperature and no actual cutting load, different rated output power levels of the laser are sequentially adjusted. After stable operation at each level, steady-state wavefront data is collected, and the steady-state average value of the corresponding higher-order aberration coefficients at each power level is statistically analyzed. The average values ​​of higher-order aberration coefficients at different output powers are integrated as a preset health benchmark. The preset health benchmark is a reference value for higher-order aberrations under ideal optical system conditions, used to determine whether the system has degraded during subsequent processing.

[0048] For example, after the laser cutting equipment completes assembly, debugging, and lens replacement and maintenance, under a constant temperature and no-load environment of 25℃, the laser output power is sequentially set to 20%, 50%, and 80% of its rated power. After each setting is run stably for 10 minutes, steady-state wavefront data is collected. Third-order and higher-order Zernike aberration coefficients are extracted through orthogonal decomposition. The steady-state average value at each power setting is calculated, yielding an average value of 0.042λ for the higher-order aberration coefficients at 20% power, 0.043λ at 50% power, and 0.044λ at 80% power. Integrating the data from these three settings, a preset health benchmark of 0.043λ for the higher-order aberrations of the optical system is obtained, serving as a reference value for judging optical component degradation and assembly abnormalities during subsequent processing.

[0049] During real-time processing, wavefront signals are continuously and synchronously acquired, and real-time higher-order aberration coefficients are calculated. Each coefficient is then compared against a preset benchmark value under the same power condition. The deviation from the preset health benchmark and the rate of change of the coefficient deviation per unit time are calculated. The deviation is obtained through difference calculation, reflecting the gap between the current optical state and the optimal state. The rate of change is obtained by calculating the deviation / unit time, used to determine whether the optical component is experiencing slow natural aging or rapid abnormal degradation. Based on industry aging test data and historical maintenance data for optical components, joint degradation judgment thresholds are pre-set for different higher-order aberration coefficients, including deviation thresholds and rate of change thresholds. For example, an abnormal degradation can be judged when the higher-order aberration coefficient deviates from the benchmark by more than 0.043λ and the hourly rate of change is greater than 0.008λ / h.

[0050] During real-time monitoring, when the deviation and rate of change of a certain higher-order aberration coefficient exceed a preset threshold, the deviation pattern and rate of change of that higher-order aberration coefficient are compared with those in the degradation feature database. This degradation feature database, based on aging test data from the optical component industry and historical maintenance data, associates different degradation types, such as lens thermal expansion, lens displacement, optical coating aging, or loosening of components, with higher-order aberration response characteristics. Through pattern matching, the most likely degradation type is identified, and combined with historical degradation rates and lifespan statistics, the remaining lifespan of the current component is calculated. For example, if the deviation of a higher-order aberration coefficient is 0.05λ and the rate of change is 0.01λ / h, which highly matches the lens thermal expansion pattern, and historical statistics show that this type of component can operate for an average of 1200 hours from reaching this deviation to failure, a health warning signal is generated, containing the specific degradation type and the estimated remaining lifespan. The degradation type is labeled as lens thermal deformation, and the estimated remaining lifespan is 1200 hours, providing maintenance personnel with timely maintenance guidance.

[0051] By utilizing the gradually varying optical wavefront aberration, minute deformations and assembly errors of optical components can be quantified in real time. By judging the degradation type and predicting the remaining lifespan based on deviations from the reference threshold, real-time monitoring and early warning of the optical system's health can be achieved, thereby preventing focus drift of the cutting head, maintaining processing accuracy, and improving the reliability and production stability of laser cutting equipment.

[0052] Based on the multidimensional vibration mode parameters, a feedforward control signal is generated to drive the beam orientation adjustment device inside the cutting head to perform a compensation action, and the residual wavefront error after compensation is extracted.

[0053] Furthermore, based on the multidimensional vibration mode parameters, a feedforward control signal is generated, including: extracting the angular vibration component of the cutting head in the beam propagation direction from the multidimensional vibration mode parameters; calculating the expected drift trajectory of the focal point on the workpiece surface based on the current focal position of the cutting head and the angular vibration component; calculating the deflection amount required to reverse the beam focal position compensation based on the expected drift trajectory; and generating a feedforward control signal to drive the beam orientation adjustment device based on the deflection amount.

[0054] Specifically, the beam propagation direction, i.e., the unit vector u-axis of the laser optical axis in the cutting head coordinate system, is determined through laser optical design or by optical axis positioning calibration during the assembly and debugging phase. For example, using the origin of the cutting head's mechanical coordinate system as a reference point, the direction cosines of the optical axis along the X, Y, and Z directions are measured and normalized to obtain the u-axis unit vector. Then, the three-dimensional vibration vector of the multi-dimensional vibration mode parameters is projected onto this optical axis direction. The angular vibration components of the cutting head in the beam propagation direction are obtained. Among them, the v mode (t) refers to the real-time vibration vector of the cutting head in three spatial directions under a certain main vibration mode. It is obtained by solving the multi-dimensional vibration mode by the vibration mode decoupling algorithm, which includes the instantaneous vibration amplitude and phase information along the X, Y and Z directions. The angular vibration component refers to the small angle deflection of the beam direction caused by the vibration of the cutting head under its support structure.

[0055] Let the focal length of the cutting head's optical system be F, the current focal position of the cutting head be (X0, Y0), and the angular vibration component be θ. Based on the principle of geometric offset of laser beam deflection, and using the current focal position (X0, Y0) and the angular vibration component θ, the focal plane offset calculation formula is applied. Where θx and θy are the angular vibration deflection angles in the X and Y orthogonal planes. Taking the current reference focus position acquired in real time as the origin, and substituting the continuously changing instantaneous angular vibration values, the real-time offset coordinates (X0+ΔX, Y0+ΔY) of the focus in the workpiece plane are calculated, and integrated in time sequence to obtain the expected drift trajectory of the laser focus on the workpiece surface.

[0056] Using the standard processing point as the target, the real-time offset direction and offset angle of the expected drift trajectory of the focus are compared. An equal-quantity reverse compensation principle is adopted, setting the reverse compensation deflection θcomplement = -θ, meaning the compensation deflection angle is equal in magnitude and completely opposite in direction to the vibration-induced angular vibration. This is used to counteract the focus shift caused by beam deflection. The standard processing point refers to the ideal position where the laser should fall on the workpiece surface under the processing requirements. It is determined based on the CAD processing path or the optical calibration point measured during the assembly and debugging stage. For example, the reference coordinates of the focus on the workpiece plane are calibrated using an optical calibration plate and used as the standard processing point. Combined with the angle-drive response calibration coefficient K built into the beam orientation adjustment device (e.g., K = 500 pulses / degree, meaning 500 drive pulse signals are output for every 1 degree of deflection), the compensation deflection is converted into standard electrical signals, pulse signals, and other drive quantities that the equipment can recognize using the control quantity conversion formula U = K × θcomplement. Signal timing matching and amplitude tuning are completed according to the equipment control cycle to generate a feedforward control signal for driving the beam orientation adjustment device, suppressing the positional drift of the laser focus on the workpiece surface from the source.

[0057] By directly converting the real-time detected vibration of the cutting head into a beam deflection control signal, the dynamic stabilization of the focal point on the workpiece surface is achieved, thereby actively eliminating the impact of vibration on machining accuracy and improving cutting quality and machining consistency.

[0058] Furthermore, driving the beam orientation adjustment device inside the cutting head to generate a compensation action and extracting the compensated residual wavefront error includes: sending the feedforward control signal to the beam orientation adjustment device; acquiring a new wavefront aberration signal within the same control cycle of the beam orientation adjustment device's action; and extracting the aberration coefficient characterizing the residual deviation of the beam pointing from the new wavefront aberration signal as the residual wavefront error.

[0059] Specifically, the generated feedforward control signal is sent in real time to the beam orientation adjustment device built into the cutting head, such as a fast-axis galvanometer or deflector, via the equipment servo drive bus, causing the beam to undergo corresponding angle compensation. Within the same control cycle of the beam orientation adjustment device's operation, new wavefront aberration signals are synchronously acquired via a wavefront sensor. Using Zernike polynomials, the newly acquired wavefront aberration signals are orthogonally decomposed to filter out aberration coefficients characterizing the residual beam pointing. These aberration coefficients are low-order tilt terms, corresponding to Zernike coefficients Z1 and Z2, directly reflecting the small angular deflection of the beam in the X and Y directions, corresponding to the small angular deflection αx and αy of the beam direction, i.e., the residual beam pointing deviation. By filtering the low-order tilt aberration coefficients and ignoring higher-order aberrations, such as focusing distortion, spherical aberration, and transient components introduced by vibration, the residual wavefront error that has not been eliminated after feedforward compensation can be obtained, providing a quantized signal for closed-loop feedback.

[0060] By performing feedforward compensation and continuously monitoring and analyzing residual wavefront errors, the compensation accuracy can be quantified, guiding the dynamic optimization of vibration suppression and beam orientation adjustment devices, thereby further improving the stability of the cutting focus and the machining accuracy.

[0061] The compensated residual wavefront error is used as feedback for closed-loop control, and the laser focus position is locked at the set position on the workpiece surface under vibration environment.

[0062] Furthermore, closed-loop control is performed using the compensated residual wavefront error as feedback to lock the laser focus position at a set position on the workpiece surface under vibration conditions. This includes: calculating the residual position deviation of the focus on the workpiece surface based on the residual beam pointing deviation characterized by the residual wavefront error and the current focus position of the cutting head; generating a feedback control signal for further correcting the beam pointing based on the residual position deviation; and superimposing the feedback control signal with the feedforward control signal to form a composite control command, which jointly drives the beam orientation adjustment device to suppress the residual position deviation and lock the focus.

[0063] Furthermore, the feedforward control signal and the feedback control signal are synthesized by frequency domain weighting, wherein the feedforward control signal is mainly used for control components above the cutoff frequency, and the feedback control signal is mainly used for control components below the cutoff frequency.

[0064] Specifically, based on the residual wavefront errors αx and αy reflecting the residual deviation of the beam direction, combined with the current focal position (xc, yc) of the cutting head and the propagation distance L of the beam from the cutting head to the workpiece surface, the residual position deviation of the focal point in the plane perpendicular to the optical axis on the workpiece surface is calculated using the small-angle approximation geometric optics relationship: By calculation, the residual wavefront error is quantified into the actual focus offset on the workpiece plane, providing accurate input for closed-loop feedback control and realizing dynamic correction of the focus position.

[0065] A PID algorithm is used to generate a feedback control signal for further beam pointing correction based on the residual position deviation. This residual position deviation is input into the PID controller, and the signal is then processed using the formula... The feedback control signal is calculated, where Kp, Ki, and Kd are the proportional, integral, and derivative gains, respectively, used for rapid response to deviations, elimination of steady-state errors, and suppression of vibration fluctuations, and Δ(t) is the residual position deviation. The feedback control signal is superimposed with the feedforward control signal, and frequency-domain weighted synthesis is performed: based on the inherent frequency of the cutting head's mechanical structure and the response characteristics of the beam orientation device, the system control cutoff frequency is preset. For example, frequency response experiments show that the main vibration of the cutting head is concentrated in the 50-500Hz range, while the beam adjustment device can quickly track 1-200Hz; therefore, a cutoff frequency of 100Hz is set as the high-low frequency boundary.

[0066] For control components with frequencies higher than the cutoff frequency, the feedforward control signal is mainly used to achieve rapid vibration suppression. For control components with frequencies lower than the cutoff frequency, the feedback control signal is mainly used. Here, the control component refers to the amplitude and phase information corresponding to each frequency component after frequency domain decomposition of the feedforward and feedback control signals. The feedforward and feedback control signal spectrum data are obtained by performing a Fast Fourier Transform (FFT) on the feedforward and feedback control signals. These spectrum data are compared with the cutoff frequency and fused according to frequency domain weights to form the final composite control command: Composite Control Signal = w1 × Feedforward Control Signal Spectrum Data + w2 × Feedback Control Signal Spectrum Data, where w1 is the weight corresponding to the feedforward control signal spectrum data and w2 is the weight corresponding to the feedback control signal spectrum data. For control components higher than the cutoff frequency, they are classified as high-frequency components, with w1 set to 0.8 and w2 set to 0.2. For control components lower than the cutoff frequency, they are classified as low-frequency components, with w1 set to 0.2 and w1 set to 0.8. The composite control signal is processed by inverse Fourier transform to obtain a time-domain composite control command. This command is then sent to the beam orientation adjustment device, which adjusts the beam direction in real time to achieve dynamic locking of the focal point on the workpiece surface, ensuring stable machining accuracy even under vibration interference.

[0067] For example, setting the beam propagation distance to 150mm, the current focal position (xc, yc) to (0, 0)mm, and the PID controller parameters Kp = 100 pulses / mm and Ki = 10 pulses / (mm) s), Kd=5 pulse The cutoff frequency is set to 100Hz, and the feedforward control signal is a 120Hz sine wave with an amplitude of 10 pulses. After feedforward compensation, the residual wavefront errors αx = 0.00002rad and αy = 0 are measured. Substituting these values ​​into the formula, the residual position deviations Δx2 = 0.003mm and Δy2 = 0 are calculated. This deviation is input into the PID controller, and simplified calculation yields a feedback control signal amplitude of approximately 0.3 pulses. After performing FFT transformation on the feedforward and feedback control signals, the 120Hz high-frequency component is weighted with a feedforward weight of 0.8 and a feedback weight of 0.2, resulting in a composite signal amplitude of 8 at that frequency. The 0Hz low-frequency component is weighted with a feedforward weight of 0.2 and a feedback weight of 0.8, resulting in a composite signal amplitude of 0.24 at that frequency. An inverse FFT transformation is then performed on the fused spectrum to obtain... The beam orientation adjustment device is driven by composite control commands to suppress residual position deviations and lock the focus dynamically at a preset position on the workpiece surface, thereby ensuring laser cutting accuracy and equipment stability. Dynamic locking of the focus on the workpiece surface is achieved through feedforward high-frequency vibration suppression and feedback low-frequency correction, ensuring stable processing accuracy.

[0068] By using dynamic composite control that rapidly suppresses high-frequency vibrations with feedforward and corrects low-frequency residuals with feedback, the laser focus remains at the preset processing position even under vibration interference and optical system drift, improving the stability and reliability of focus position locking, thereby ensuring the accuracy and quality of cutting processing.

[0069] Example 2, based on the same inventive concept as the online vibration detection method for the cutting head of the laser cutting equipment in the foregoing examples, such as... Figure 2 As shown, this application provides an online vibration detection system for a cutting head of a laser cutting equipment, wherein the online vibration detection system for a cutting head of a laser cutting equipment includes: The signal separation module 11 is used to synchronously acquire the wavefront aberration signal of the processing laser emitted by the laser cutting equipment during laser processing, and to separate the periodic aberration disturbance component with the same frequency as the mechanical vibration and the slowly varying aberration background component determined by the state of the optical elements from the wavefront aberration signal in real time. The health status assessment module 12 is used to calculate the multidimensional vibration mode parameters of the cutting head in space based on the periodic aberration disturbance component, and at the same time, to assess the health status of the optical system and generate a health warning signal based on the deviation of the slowly varying aberration background component from the preset benchmark. The compensation drive module 13 is used to generate a feedforward control signal based on the multidimensional vibration mode parameters, drive the beam orientation adjustment device inside the cutting head to generate a compensation action, and extract the residual wavefront error after compensation. The closed-loop control module 14 is used to perform closed-loop control with the residual wavefront error after compensation as feedback, and lock the laser focus position at a set position on the workpiece surface in a vibration environment.

[0070] Furthermore, the signal separation module 11 is also used to: perform orthogonal decomposition on the wavefront aberration signal to obtain a time series containing multiple basis function coefficients; take the first-order aberration coefficients representing the overall tilt of the beam in the basis function coefficients as the characteristic signal for vibration decoupling analysis; perform spectral analysis on the characteristic signal, and reconstruct the specific frequency band energy related to the natural frequency of the cutting head's mechanical structure in the spectrum into a time-domain signal as the periodic aberration perturbation component; and filter out the periodic aberration perturbation component from the time series of the basis function coefficients to obtain the slowly varying aberration background component.

[0071] Furthermore, the health status assessment module 12 is also used to: establish a correspondence model between the vibration direction vector of the main vibration mode and a specific combination of basis function coefficients in the wavefront aberration signal for at least one main vibration mode determined by the mechanical structure of the cutting head; extract the real-time amplitude and phase information of the specific combination of basis function coefficients from the periodic aberration perturbation components; input the real-time amplitude and phase information, as well as the real-time pose information of the cutting head during processing, into the correspondence model to calculate the multidimensional vibration mode parameters of the cutting head under the main vibration mode, wherein the multidimensional vibration mode parameters include at least the equivalent vibration amplitude and direction in the workpiece coordinate system.

[0072] Furthermore, the health status assessment module 12 is also used to: apply a standard vibration excitation matching the main vibration mode to the cutting head, and simultaneously acquire the calibration wavefront aberration signal under the standard vibration excitation; separate the periodic aberration disturbance component caused by the standard vibration excitation from the calibration wavefront aberration signal as the calibration disturbance component; identify the basis function coefficients that produce a stable response to the standard vibration excitation from the calibration disturbance component as a specific basis function coefficient combination, and record its response amplitude and phase; and establish the correspondence model based on the vibration direction vector of the standard vibration excitation and the response amplitude and phase of the specific basis function coefficient combination.

[0073] Furthermore, the health status assessment module 12 is also used to: extract higher-order aberration coefficients from the slowly varying aberration background components that are sensitive to changes in the surface shape of optical elements and assembly errors; after the equipment has been assembled or maintained, under constant temperature and no processing load conditions, record the average value of higher-order aberration coefficients at different output powers to establish a preset health benchmark; during real-time processing, monitor the deviation of the higher-order aberration coefficients from the preset benchmark and their rate of change in real time; when the deviation of any higher-order aberration coefficient and its rate of change exceed a preset degradation judgment threshold, generate a health warning signal containing the specific degradation type and the estimated remaining service life.

[0074] Furthermore, the compensation drive module 13 is also used to: extract the angular vibration component of the cutting head in the beam propagation direction from the multidimensional vibration mode parameters; calculate the expected drift trajectory of the focal point on the workpiece surface based on the current focal position of the cutting head and the angular vibration component; calculate the deflection amount required to reverse the beam focal position compensation based on the expected drift trajectory; and generate a feedforward control signal for driving the beam orientation adjustment device based on the deflection amount.

[0075] Furthermore, the compensation drive module 13 is also used to: send the feedforward control signal to the beam orientation adjustment device; acquire a new wavefront aberration signal within the same control cycle of the beam orientation adjustment device operation; and extract the aberration coefficient characterizing the residual beam pointing deviation from the new wavefront aberration signal as the residual wavefront error.

[0076] Furthermore, the closed-loop control module 14 is also used to: calculate the residual position deviation of the focus on the workpiece surface based on the residual beam pointing residual deviation characterized by the residual wavefront error and the current focus position of the cutting head; generate a feedback control signal for further correcting the beam pointing based on the residual position deviation; and superimpose the feedback control signal with the feedforward control signal to form a composite control command, which jointly drives the beam orientation adjustment device to suppress the residual position deviation and lock the focus.

[0077] Furthermore, the closed-loop control module 14 is also used to: perform frequency domain weighted synthesis of the feedforward control signal and the feedback control signal, wherein the feedforward control signal is mainly used for control components above the cutoff frequency, and the feedback control signal is mainly used for control components below the cutoff frequency.

[0078] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The online vibration detection method and specific examples for the cutting head of a laser cutting equipment in the foregoing embodiment one are also applicable to the online vibration detection system for the cutting head of a laser cutting equipment in this embodiment. Through the foregoing detailed description of the online vibration detection method for the cutting head of a laser cutting equipment, those skilled in the art can clearly understand the online vibration detection system for the cutting head of a laser cutting equipment in this embodiment. Therefore, for the sake of brevity, it will not be described in detail here.

[0079] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0080] Obviously, those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A method for online detection of vibration of a cutting head in laser cutting equipment, characterized in that, The method includes: During laser processing, the wavefront aberration signal of the processing laser emitted by the laser cutting equipment is acquired synchronously, and the periodic aberration disturbance component with the same frequency as the mechanical vibration and the slowly varying aberration background component determined by the state of the optical elements are separated from the wavefront aberration signal in real time. Based on the periodic aberration perturbation components, the multidimensional vibration mode parameters of the cutting head in space are calculated. At the same time, based on the deviation of the slowly varying aberration background components from the preset benchmark, the health status of the optical system is evaluated and a health warning signal is generated. Based on the multidimensional vibration mode parameters, a feedforward control signal is generated to drive the beam orientation adjustment device inside the cutting head to perform a compensation action, and the residual wavefront error after compensation is extracted. The compensated residual wavefront error is used as feedback for closed-loop control, and the laser focus position is locked at the set position on the workpiece surface under vibration environment.

2. The online vibration detection method for a cutting head in a laser cutting equipment as described in claim 1, characterized in that, From the wavefront aberration signal, the periodic aberration perturbation component with the same frequency as the mechanical vibration and the slowly varying aberration background component determined by the state of the optical elements are separated in real time, including: The wavefront aberration signal is orthogonally decomposed to obtain a time series containing multiple basis function coefficients; The first-order aberration coefficients, which characterize the overall tilt of the beam, are used as the characteristic signals for vibration decoupling analysis. Spectral analysis is performed on the characteristic signal, and the specific frequency band energy related to the inherent frequency of the cutting head's mechanical structure in the spectrum is reconstructed into a time-domain signal, which serves as the periodic aberration perturbation component. The periodic aberration perturbation component is filtered out from the time series of the basis function coefficients to obtain the slowly varying aberration background component.

3. The online vibration detection method for a cutting head in a laser cutting equipment as described in claim 1, characterized in that, Based on the periodic aberration perturbation components, the multidimensional vibration mode parameters of the cutting head in space are calculated, including: For at least one principal vibration mode determined by the mechanical structure of the cutting head, a correspondence model is established between the vibration direction vector of the principal vibration mode and a specific combination of basis function coefficients in the wavefront aberration signal; Real-time amplitude and phase information of the specific basis function coefficient combination are extracted from the periodic aberration perturbation components; The real-time amplitude and phase information, as well as the real-time pose information of the cutting head during the processing, are input into the corresponding relationship model to calculate the multi-dimensional vibration mode parameters of the cutting head under the main vibration mode. The multi-dimensional vibration mode parameters include at least the equivalent vibration amplitude and direction in the workpiece coordinate system.

4. The online vibration detection method for a cutting head in a laser cutting equipment as described in claim 3, characterized in that, A model is established to model the correspondence between the vibration direction vector of the principal vibration mode and a specific combination of basis function coefficients in the wavefront aberration signal, including: A standard vibration excitation matching the main vibration mode is applied to the cutting head, and the calibrated wavefront aberration signal under the standard vibration excitation is acquired simultaneously. The periodic aberration component caused by standard vibration excitation is separated from the calibration wavefront aberration signal and used as the calibration perturbation component; From the calibrated disturbance components, the basis function coefficients that produce a stable response to the standard vibration excitation are identified as a specific combination of basis function coefficients, and their response amplitude and phase are recorded. Based on the vibration direction vector of the standard vibration excitation and the response amplitude and phase of the specific basis function coefficients, the corresponding relationship model is established.

5. The online vibration detection method for a cutting head in a laser cutting equipment as described in claim 3, characterized in that, Based on the deviation of the slowly varying aberration background component from a preset reference, the health status of the optical system is assessed and a health warning signal is generated, including: Extract the higher-order aberration coefficients from the slowly varying aberration background components that are sensitive to changes in the surface shape of optical elements and assembly errors; After the equipment is installed, adjusted or maintained, under constant temperature and no processing load conditions, record the average value of higher-order aberration coefficients under different output powers to establish a preset health benchmark. During real-time processing, the deviation of the higher-order aberration coefficients relative to the preset reference and its rate of change are monitored in real time. When the deviation of any higher-order aberration coefficient and the combination of its rate of change exceed the preset degradation judgment threshold, a health warning signal containing the specific degradation type and the estimated remaining service life is generated.

6. The online vibration detection method for a cutting head in a laser cutting equipment as described in claim 1, characterized in that, Based on the aforementioned multidimensional vibration modal parameters, a feedforward control signal is generated, including: The angular vibration component of the cutting head in the beam propagation direction is extracted from the multidimensional vibration mode parameters. The expected drift trajectory of the focal point on the workpiece surface is calculated based on the current focal position of the cutting head and the angular vibration component. Based on the expected drift trajectory, the amount of deflection required to reverse the beam focal position is calculated, and a feedforward control signal for driving the beam orientation adjustment device is generated based on the amount of deflection.

7. The online vibration detection method for a cutting head in a laser cutting equipment as described in claim 6, characterized in that, The beam orientation adjustment device inside the cutting head is driven to generate a compensation action, and the compensated residual wavefront error is extracted, including: The feedforward control signal is sent to the beam orientation adjustment device; During the same control cycle of the beam orientation adjustment device, a new wavefront aberration signal is acquired; From the new wavefront aberration signal, the aberration coefficients characterizing the residual deviation of the beam pointing are extracted as the residual wavefront error.

8. The online vibration detection method for a cutting head in a laser cutting equipment as described in claim 1, characterized in that, Using the compensated residual wavefront error as feedback for closed-loop control, the laser focus position is locked at a set position on the workpiece surface under vibration conditions, including: Based on the residual beam pointing deviation characterized by the residual wavefront error and the current focal position of the cutting head, the residual position deviation of the focal point on the workpiece surface is calculated. Based on the residual position deviation, a feedback control signal is generated for further correcting the beam direction; The feedback control signal and the feedforward control signal are superimposed to form a composite control command, which jointly drives the beam orientation adjustment device to suppress the residual position deviation and lock the focus.

9. The online vibration detection method for a cutting head in a laser cutting equipment as described in claim 8, characterized in that, The method further includes: The feedforward control signal and the feedback control signal are combined by frequency domain weighting. For control components above the cutoff frequency, the feedforward control signal is mainly used, and for control components below the cutoff frequency, the feedback control signal is mainly used.

10. An online vibration detection system for a laser cutting head, characterized in that, The steps for implementing the online vibration detection method for a cutting head of a laser cutting equipment according to any one of claims 1 to 9 include: The signal separation module is used to simultaneously acquire the wavefront aberration signal of the processing laser emitted by the laser cutting equipment during the laser processing process, and to separate the periodic aberration disturbance component with the same frequency as the mechanical vibration and the slowly varying aberration background component determined by the state of the optical elements from the wavefront aberration signal in real time. The health status assessment module is used to calculate the multidimensional vibration mode parameters of the cutting head in space based on the periodic aberration perturbation component. At the same time, based on the deviation of the slowly varying aberration background component from the preset benchmark, it assesses the health status of the optical system and generates a health warning signal. The compensation drive module is used to generate a feedforward control signal based on the multidimensional vibration mode parameters, drive the beam orientation adjustment device inside the cutting head to perform a compensation action, and extract the residual wavefront error after compensation. The closed-loop control module is used to perform closed-loop control with the compensated residual wavefront error as feedback, and locks the laser focus position to a set position on the workpiece surface in a vibration environment.

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