Precise metal plate laser cutting process parameter self-adaptive control system

Abstract

The invention relates to the technical field of industrial automation control, and discloses a precise sheet metal laser cutting process parameter self-adaptive control system, which comprises an instruction analysis unit, a laser cutting unit, a laser cutting unit, a laser cutting unit, a laser cutting unit and a laser cutting unit, the density operation unit constructs a virtual space-time sliding window, executes virtual track injection logic to convert static perforation into a virtual track data packet, and calculates a local energy density index in combination with a laser opening track segment; the parameter adjusting unit generates a basic pulse modulation coefficient based on the index, and generates a spatial discrete trigger signal when the index and the geometric curvature feature simultaneously exceed a threshold value; according to the virtual track injection and space-time sliding window mechanism, the data blind area of the static perforation action in the dynamic control model is eliminated, the overburning problem at the zero-speed singular point is solved through the modulation domain switching logic, and the machining quality of a complex contour is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a precision sheet metal laser cutting process parameter adaptive control system, belonging to the field of industrial automation control technology. BACKGROUND

[0002] In current precision metal part manufacturing, laser cutting control systems generally use speed and power coupling control strategy. The strategy establishes a function relationship between laser output power and cutting head moving speed, monitors the real-time motion speed of the cutting head to adjust the laser output power, maintains the constant energy density of the unit cutting path line, and ensures the consistency of the cutting section quality. The existing technology improves the processing quality by limiting hardware improvement, relying on the optimization of transmission component morphology or the enhancement of mechanical structure rigidity, which is difficult to solve the dynamic energy matching of complex trajectory, and the control strategy is externally constrained mechanism. For example, the Chinese invention patent with the authorization announcement number CN120326197B discloses a laser cutting device and process for precision sheet metal component processing, which sets auxiliary tooth-shaped groove support net plate and multiple adjustable positioning clamps, uses mechanical limiting to strengthen the spatial stability of sheet metal components, solves the shaking displacement of thin plate processing, strengthens the physical constraint to ensure the static position accuracy of the workpiece, and the process control logic still stops at the static clamping open-loop cutting. The heat history space-time correlation evaluation of the cutting path is not built, and it is difficult to perceive the local heat accumulation state when facing high-density array holes or complex topological features with sharp turns. The energy is output according to the preset fixed parameters, although the position ignores the temperature, which causes the mismatch between laser energy input and material heat bearing capacity, and the fine profile or variable speed motion segment is easily burned, fused or hung slag due to the inability to dissipate heat in time.

[0003] However, the control mode based on instantaneous motion state ignores the heat residual effect in the spatial neighborhood of the historical processing path. When high-density array features or continuous sharp turning profiles are processed, the cutting head continuously traverses the spatial adjacent area in a short time, and the heat generated by the previous processing has not been dissipated, which causes the temperature at the current processing position to rise. At this time, only the output power according to the current speed is superimposed on the heat input, which exceeds the material bearing threshold, causing overburning or fusion. The conventional control model is difficult to handle the energy connection between static dwell action and dynamic cutting process. Laser drilling is a high-energy input static process with zero displacement, which cannot be characterized by a dynamic model based on motion trajectory. Therefore, the system transitions from static drilling to motion cutting, lacks a mechanism to compensate for residual heat from drilling, and causes the hole to burst at the starting point. In addition, at the kinematic singularity of the trajectory sharp corner, the speed of the servo shaft tends to zero, and the fixed frequency pulse width modulation causes the laser pulses in the unit spatial distance to be infinitely stacked, forming an energy density singularity.

[0004] Therefore, how to build a dynamic evaluation mechanism that integrates time series historical data and spatial neighborhood features to solve the energy control mismatch problem in static action and extremely low speed working conditions has become a technical problem to be solved by the present application. SUMMARY

[0005] To solve the problems presented in the background art, the technical solutions of the present application are as follows: A precise sheet metal laser cutting process parameter adaptive control system, the system comprises an instruction analysis unit, a density calculation unit, a parameter adjustment unit and an output control unit: The instruction analysis unit reads the pre-read buffer instruction sequence of the numerical control machining program and extracts geometric coordinates and feed speed, constructs a four-dimensional data stream based on relative time stamps for the trajectory nodes in the instruction sequence, and identifies static piercing action instructions in the instruction sequence; The density calculation unit constructs a virtual space-time sliding window centered on the target trajectory point to be processed, executes a virtual trajectory injection logic, calculates the equivalent virtual trajectory length based on the piercing energy parameter set by the static piercing action instruction and the preset standard line energy density, constructs a virtual trajectory data packet with the equivalent virtual trajectory length and the spatial coordinates anchored at the piercing position, and injects the calculation queue of the space-time sliding window. The density calculation unit selects the effective laser on trajectory segment and the virtual trajectory data packet falling into the space-time sliding window, and performs time difference-based attenuation weighted accumulation on them, to generate a local energy density index representing the local heat accumulation level of the target trajectory point; The parameter adjustment unit generates a basic pulse modulation coefficient based on the local energy density index according to a preset density parameter mapping relationship, and executes modulation domain switching logic, generates a spatial discrete trigger signal when detecting that the local energy density index exceeds a first threshold and the geometric curvature feature of the target trajectory point exceeds a second threshold; The output control unit uses the basic pulse modulation coefficient to control the pulse duty cycle of the laser in real time, and in response to the spatial discrete trigger signal, switches the control mode of the laser from the pulse width modulation mode based on the time period to the position synchronous output mode based on the axis movement distance, to lock the number of laser pulses within a unit spatial distance.

[0006] Preferably, the density calculation unit calculates the equivalent virtual trajectory length when executing the virtual trajectory injection logic using the following calculation rules: Wherein, represents the equivalent virtual trajectory length, represents the piercing power set by the static piercing action instruction, represents the dwell time set by the static piercing action instruction, represents the preset standard line energy density; the density calculation unit sets the time attribute of the generated virtual trajectory data packet to the starting time of the subsequent cutting action, to maintain the continuity of the thermal field data evolution in the space-time sliding window.

[0007] Preferably, the density operation unit further executes heat conduction boundary correction logic, when constructing the spatio-temporal sliding window, identifying the historical trajectory points whose machining state in the instruction sequence is completed, counting the topological obstruction density of the historical trajectory points whose machining state is completed within the spatio-temporal sliding window; the density operation unit generates a thermal barrier gain coefficient according to the topological obstruction density, and performs forward weighting correction on the local energy density index by using the thermal barrier gain coefficient, so as to compensate the heat diffusion blocking effect caused by the material continuity being cut off.

[0008] Preferably, the system further comprises a signal feature analysis unit connected to the laser cutting head height adjustment sensor; the signal feature analysis unit extracts a high-frequency noise component in the capacitance signal of the height adjustment sensor, and calculates a statistical dispersion index of the high-frequency noise component within a unit time window; the parameter adjustment unit generates a global attenuation coefficient and performs secondary weighting correction on the basic pulse modulation coefficient when the statistical dispersion index exceeds a preset stability threshold.

[0009] Preferably, the instruction analysis unit calculates the geometric curvature feature by analyzing the included angle of adjacent trajectory vectors; the modulation domain switching logic in the parameter adjustment unit is configured with a hysteresis comparison function, and only when the geometric curvature feature falls below a safe hysteresis value of the second threshold value, the operation of releasing the spatial dispersion trigger signal is triggered, so that the control mode of the laser is restored to the pulse width modulation mode based on the time period.

[0010] Preferably, the density operation unit applies a time decay weight function that monotonically decreases with the increase of time difference when calculating the local energy density index; the decay rate constant of the time decay weight function is set based on the thermal diffusion coefficient of the machined plate; the density operation unit only includes the effective laser-on trajectory segment with a time difference less than the thermal dissipation time constant from the target trajectory point in the weighted accumulation calculation.

[0011] Preferably, the parameter adjustment unit further executes cooling insertion logic, generates a stay instruction and inserts it before the machining instruction of the target trajectory point when the calculated local energy density index exceeds a preset limit threshold; the output control unit controls the laser to turn off the laser output and maintain the auxiliary gas output in response to the stay instruction until the real-time local energy density index calculated by the density operation unit decreases to the allowable threshold.

[0012] Preferably, the signal feature analysis unit comprises a high-pass filter and a variance operation module; the high-pass filter filters out the direct current and low-frequency components in the capacitance signal representing the change of the cutting head height, and retains the high-frequency alternating current components representing the fluctuation of the plasma cloud; the variance operation module performs sliding window variance calculation on the retained high-frequency alternating current components to obtain the statistical dispersion index.

[0013] Preferably, the virtual trajectory data packet contains spatial coordinates, time stamps and laser on-off status bits consistent with the actual machining trajectory data structure, but its corresponding physical axis movement speed is zero; the density calculation unit treats it as a real trajectory segment with non-zero energy density when processing the virtual trajectory data packet, and performs heat accumulation contribution calculation.

[0014] Preferably, the output control unit, in the position synchronization output mode, masks the clock trigger signal inside the laser, and establishes a hardware mapping connection with the servo motor encoder feedback pulse, triggering a laser pulse output once every time the cutting head moves a preset fixed spatial step.

[0015] Compared with the prior art, the present application has the following advantages: 1. In precise sheet metal laser cutting, a space-time sliding window evaluation mechanism is constructed for instruction stream data, the control adjustment dimension is expanded from a single instantaneous speed to historical trajectory data space-time convolution, the density calculation unit extracts the implicit time sequence and spatial characteristics of the machining instruction sequence, performs time decay weighted operation on the laser on-off trajectory segment falling within the sliding window range, calculates the local heat accumulation level energy density index, and the data processing mechanism predicts the heat residual effect in the current spatial neighborhood before executing the action according to the instruction stream history and future distribution, thereby generating a dynamic duty cycle suppression coefficient, ensuring that the net energy acting on the controlled object maintains constant in dense path areas or complex geometric contours, and eliminating the consistency deviation caused by ignoring the space-time correlation in the existing control strategy.

[0016] 2. Heterogeneous data isomorphism translation logic is established, the system identifies the static piercing instruction definition energy parameter, converts it into a virtual trajectory data segment of a specific length according to the principle of energy conservation, and injects it into the sliding window calculation queue of the density calculation unit. This data processing method eliminates the dimensional gap between static high-energy actions and dynamic evaluation models, so that the control system can automatically generate a suppression characteristic modulation coefficient based on the cumulative calculation results of the virtual data in the transition stage from static piercing to dynamic cutting, realizing the uniform and continuous mapping of thermal state data in the control model throughout the entire process.

[0017] 3. When the modulation domain dynamic switching logic detects a coexistence condition of high local energy density and high geometric curvature, it blocks the time period pulse trigger signal based on the time period pulse trigger signal, and generates a spatial discrete trigger instruction using the position feedback signal. This logic migrates the laser control reference from the time domain to the spatial domain, locks the number of pulse triggers within a unit movement distance, and dynamically migrates the orthogonal control reference, so that even at the kinematic singularity where the servo shaft movement speed tends to zero, the spatial distribution density of the output energy remains linearly controlled, solving the problem of energy out of control caused by infinite stacking of pulses in the spatial domain under extremely low speed conditions. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1This is a closed-loop logic flowchart of the adaptive control system for process parameters of the present invention; Fig. 2 This is a bar chart comparing the response time of the system of the present invention with that of the traditional PV control strategy; Fig. 3 This is a schematic diagram of the hierarchical architecture for the collaboration between the digital computing domain and the physical execution domain of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] This invention discloses an adaptive control system for precision sheet metal laser cutting process parameters, comprising four core logic modules: an instruction parsing unit, a density calculation unit, a parameter adjustment unit, and an output control unit. These units communicate at high speed via a real-time data bus to achieve closed-loop control from processing instructions to laser energy output. The instruction parsing unit, as the system's input front-end, is responsible for reading the instruction sequence from the pre-read buffer of the CNC machining program. This unit not only extracts the geometric coordinates and feed rate information from the instructions but also, based on a preset feed rate, assigns a relative timestamp to each trajectory node in the instruction sequence, thereby transforming the originally discrete static geometric code into a four-dimensional data stream containing spatial position, motion speed, and time dimensions. When dealing with the piercing action commonly found in actual sheet metal processing scenarios, since the piercing process is a static physical process with zero displacement but extremely high energy input, conventional speed-based control models often misjudge it as a cold region due to the inability to detect displacement, leading to overheating or bursting during the initial cutting stage. Therefore, the instruction parsing unit is configured to identify the static piercing action instructions in the instruction sequence and trigger the density calculation unit to execute the virtual trajectory injection logic, and then adjust the piercing power according to the static piercing action instructions. Duration of stay and the preset standard line energy density selected by the current process. Using the rules of operation Calculate the length of the equivalent virtual trajectory This leads to the construction of a virtual trajectory with the equivalent length. and the spatial coordinate is anchored to the virtual trajectory data packet at the piercing position, and the time attribute of the virtual trajectory data packet is set to the starting time immediately after the subsequent cutting action, and the virtual trajectory data packet is injected into the calculation queue of the space-time sliding window, so that the static heat input is converted into dynamic trajectory data at the mathematical model level, and it is ensured that the heat history stored in the material is continuously mapped in the control model.

[0021] The density operation unit undertakes the core task of quantifying the local heat accumulation level. The unit constructs a virtual space-time sliding window centered on the current target trajectory point to be processed, and the spatial coverage range is set according to the heat affected zone characteristic radius of the processed plate, and the time correlation range is determined based on the thermal diffusion coefficient of the material. When performing operations, the density operation unit selects all effective laser-on trajectory segments and the aforementioned injected virtual trajectory data packets within the range of the space-time sliding window, and performs weighted and accumulated calculation on the time difference and spatial distance of these trajectory segments relative to the target trajectory point, to generate a local energy density index representing the local heat accumulation level of the target trajectory point. For non-continuous medium areas such as nested nesting or thin-walled skeleton commonly seen in complex contour processing, the completed cutting seam will block the lateral diffusion of heat, causing heat to accumulate abnormally in the remaining material. The density operation unit further executes a heat conduction boundary correction logic, that is, when constructing the space-time sliding window, it simultaneously identifies the historical trajectory points in the instruction sequence whose processing state is completed, and counts the distribution density of these completed points within the sliding window, i.e. the topological blocking density. When the density exceeds a preset threshold, a thermal barrier gain coefficient is generated to positively weight and correct the local energy density index, so as to compensate for the heat diffusion blocking effect caused by the discontinuity of the material structure, and ensure that the system can perceive the drift of the heat boundary condition caused by the change of the structure topology.

[0022] The parameter adjustment unit generates corresponding basic pulse modulation coefficients according to the real-time calculated local energy density index based on the preset density parameter mapping relationship, which is used to dynamically suppress the output power of the laser. In the case of kinematic singularity such as a corner with a very small radius or a sharp corner, the physical movement speed of the servo shaft will tend to zero. At this time, if only the pulse width modulation mode based on the time period is used, even if the duty cycle is very low, the number of laser pulses stacked in the unit space distance will still tend to infinity, causing overheating. To address this physical failure boundary, the parameter adjustment unit is also configured with modulation domain switching logic and real-time monitoring of the geometric curvature characteristics of the target trajectory point. When the local energy density index exceeds the first threshold and the geometric curvature characteristics also exceed the second threshold, it is determined that the current is in an extreme working condition of high heat and low speed, and a space discrete trigger signal is generated immediately.

[0023] The output control unit switches the control mode of the laser from the internal clock triggered time cycle based pulse width modulation mode to the position synchronous output mode based on the shaft movement distance in response to the spatial discrete trigger signal, the system shields the internal clock of the laser, establishes a hardware mapping connection with the feedback pulse of the servo motor encoder, strictly locks the laser pulse output to trigger once for every preset fixed spatial step of the cutting head, thereby constraining the density of energy input in the spatial domain and eliminating the spot overlap effect in the low speed movement state. In addition, the system also includes a signal feature analysis unit connected to the height adjustment sensor of the laser cutting head, which is used to deal with non-modeled disturbances such as lens contamination or gas purity fluctuations. The unit extracts the high frequency noise component in the capacitance signal of the height adjustment sensor through a high pass filter, and calculates the statistical dispersion index of the component in the unit time window. When the index exceeds the preset stability threshold, the parameter adjustment unit generates a global attenuation coefficient to make secondary weighted correction to the basic pulse modulation coefficient, so as to compensate the influence of environmental disturbance on the processing stability in a closed loop manner. The parameter adjustment unit also executes the cooling insertion logic. When the calculated local energy density index exceeds the preset limit threshold, the parameter adjustment unit generates a stay instruction and inserts it before the processing instruction of the target trajectory point. The output control unit responds to the stay instruction to control the laser to close the laser output and maintain the auxiliary gas output until the real-time local energy density index calculated by the density calculation unit decreases to the allowable threshold.

[0024] Embodiment 1: In the industrial application scenario of processing the heat dissipation hole array of high-density electronic shielding cover, containing thousands of closely arranged micro hexagonal holes in honeycomb shape, the rib width between the holes is only times the thickness of the plate, and the working condition requires to maintain high production rhythm while ensuring that all hole walls are not over-burned and the sharp corners are not molten. When the system analyzes the starting processing instruction of each hexagonal hole, the instruction analysis unit identifies the accompanying static piercing action instruction. At this time, the density calculation unit does not wait for the occurrence of physical displacement, but executes the virtual trajectory injection logic. According to the piercing power , residence time and preset standard line energy density selected by the current process in the piercing action instruction, the equivalent virtual trajectory length is calculated by using the operation rule , and the virtual trajectory data packet with the length and anchored in the piercing coordinate is injected into the blank space-time sliding window calculation queue, so that the density calculation unit can calculate the high local energy density index based on the data containing the virtual heat history at the starting moment of cutting, thereby driving the parameter adjustment unit to generate a greatly attenuated basic pulse modulation coefficient in the starting stage to suppress the burst hole phenomenon caused by the superposition of piercing residual heat and starting high energy.

[0025] As the cutting head moves at high speed along the hexagonal trajectory, the density operation unit continuously maintains the virtual time-space sliding window, not only counting the effective laser opening trajectory segment in the current hole, but also synchronously scanning the historical hole trajectory in the neighborhood whose state identifier is completed. When a large number of completed cutting seams are detected within the sliding window range, the system determines that the current is in the narrow muscle area where heat diffusion is blocked, and then generates a heat barrier gain coefficient greater than according to the statistical topological barrier density to positively weight and correct the local energy density index, so that the output control unit further reduces the duty cycle to match the limited heat dissipation condition. When the cutting head approaches each sharp corner point of the hexagonal trajectory, the servo axis feed speed naturally decreases to near zero due to kinematic constraints. At this time, the parameter adjustment unit detects that the real-time calculated local energy density index is continuously maintained at a high level, and the geometric curvature feature extracted by the instruction analysis unit simultaneously exceeds the preset second threshold value. The system determines that a singular point working condition coexists with high heat accumulation and low speed motion, and then generates a spatial discrete trigger signal to drive the output control unit to shield the internal clock of the laser, and instead establish a hardware mapping with the servo encoder, and switch the control mode to a position synchronous output mode based on the axis movement distance, and lock the number of laser pulse triggers within a unit space distance.

[0026] In the continuous processing of high-density arrays, as the cutting path gradually advances to the geometric center area of the workpiece, the overall background temperature of the material increases cumulatively due to the dense distribution of the surrounding processed holes. The local energy density index calculated by the density operation unit in real time may instantaneously exceed the preset limit threshold in the local area. For this heat saturation critical condition, the parameter adjustment unit activates the cooling insertion logic to automatically insert a stay instruction that only maintains auxiliary gas injection into the current processing instruction sequence. The output control unit temporarily blocks the emission of the laser beam, and uses the forced convection effect of high-speed airflow to accelerate heat dissipation, until the real-time local energy density index calculated by the density operation unit according to the heat diffusion model falls within the safe allowable threshold range. The system automatically resumes laser output and continues to execute the subsequent cutting path, thereby effectively preventing local melting or substrate deformation in the center area of the array due to the inability of heat to be conducted by the medium in time. This control process automatically maintains the dynamic balance between the overall processing energy input and the local heat bearing capacity of the material by real-time analysis and response to the time-space heat history and geometric features contained in the instruction stream without manual intervention in perforation parameters or individual angular point processes.

[0027] Example 2: Construct a comparative verification test on a standardized industrial laser processing test platform, which is equipped with a fiber laser cutting machine with a rated power of (wavelength ), and a set of high-speed field bus (sampling period The open CNC system of the application is used for real-time acquisition and recording of the motion state of each axis and the laser output parameter in the machining process. The SUS304 stainless steel plate with a thickness of 0.5 mm is selected as the material for the test, and the test sample is designed as a composite geometric profile including a continuous right-angle corner, a micro-hole array (hole diameter , pitch ) and a variable curvature spline curve, aiming to simulate the complex topology and variable speed working condition commonly seen in actual production. The test design includes two groups of control samples: the control group adopts the traditional speed-power (P-V) coupling control strategy, that is, the laser power only changes linearly with the real-time feeding speed; the sample group of the application completely enables the adaptive control system including instruction analysis, density calculation, parameter adjustment and output control. During the test process, the machining quality indicators of the sample at the starting perforation point, the continuous small hole area and the right-angle sharp corner are monitored and recorded, including the heat affected zone (HAZ) width, the slag height and the sharp corner profile error. In order to quantify the response capability of the system to the thermal accumulation effect, a thermocouple sensor is embedded on the back surface of the dense small hole area to monitor the local temperature rise curve in the machining process.

[0028] For the starting perforation stage, the control group lacks the memory mechanism of the static perforation energy, and at the moment when the perforation ends and the cutting starts , the system detects the speed jump and outputs high power, resulting in obvious burst holes and overburning near the starting point, and the average heat affected zone width reaches . In contrast, the sample group of the application identifies the perforation action through the instruction analysis unit, and executes the virtual trajectory injection logic through the density calculation unit, constructs a virtual trajectory data packet with an equivalent length of , and injects the local energy density index calculated by the system at the starting moment to be at a high level, so as to drive the parameter adjustment unit to suppress the initial pulse modulation coefficient to below , realizing the smooth transition of energy. The measured data shows that the heat affected zone width at the starting point of the sample group of the application is only , and the burst hole rate is reduced to .

[0029] In the dense small hole array machining area, the temperature rise data collected by the thermocouple shows that with the increase of the number of machined holes, the local substrate temperature of the control group presents a stepwise rising trend, and the peak temperature at the th hole position exceeds , resulting in obvious collapse and slag at the subsequent hole positions, and the average slag height reaches . The sample group of the application uses the time-space sliding window constructed by the density calculation unit to realize real-time statistics of the set feature radius within the sliding window range the effective laser opening trajectory segment and the topological barrier density of the completed trajectory, when the local heat accumulation index gradually increases with the processing progress, the parameter adjustment unit dynamically reduces the basic pulse modulation coefficient, so that the peak temperature of the whole array region is always controlled within , the average slag hanging height is reduced to , and the standard deviation of the aperture consistency is better than , which proves that the spatiotemporal sliding window mechanism can accurately suppress the heat accumulation effect; for the kinematic singularity working condition at the right-angle sharp corner, when the feed speed of the control group is reduced to , although the power decreases with the speed, due to the fixed pulse frequency, the spot overlap rate per unit length increases sharply, resulting in the appearance of the round corner feature at the sharp corner, and the measured sharp corner profile error reaches , when the geometric curvature feature of the inventive sample group exceeds the second threshold set to and the local energy density index is high, the output control unit generates a spatially discrete trigger signal, switches the control mode to a position-synchronous output mode (PSO), locks the fixed spatial step distance to trigger the laser pulse, microscopic observation results show that the sharp corner profile processed by the inventive sample group is clear and sharp, without over-melting phenomenon, and the sharp corner profile error is only , solving the problem of energy accumulation at low speed. Table 1 summarizes the comparison data of the key performance indicators of the above tests.

[0030] Table 1: Comparison of key processing performance indicators

[0031] Based on the above test results and data analysis, the present application successfully solves the problems of static perforation heat residue, dense path heat accumulation and zero-speed singularity burning under a single control architecture by introducing virtual trajectory injection, spatiotemporal sliding window evaluation and modulation domain dynamic switching core mechanisms.

[0032] Embodiment 3: This embodiment combines Figs. 1 to 3 , to explain a kind of precision sheet metal laser cutting process parameter adaptive control system, such as Fig. 1As shown, the flow starts with the system reading the pre-read buffer instruction sequence in the numerical control machining program, the instruction parsing unit processes the sequence to identify static piercing actions and build a four-dimensional data stream containing geometric and time information, and enters the density operation unit, where the system performs virtual trajectory injection logic and calculates the local energy density index representing the state of heat accumulation, which is passed to the parameter adjustment unit as the core control variable to generate the basic pulse modulation coefficient and determine whether to execute the modulation domain switching logic, while the signal feature analysis unit connected to the height sensor extracts the high-frequency noise component in the capacitive signal feedback and calculates the statistical dispersion index, which is fed back to the parameter adjustment unit as a secondary weighting correction parameter to dynamically calibrate the modulation coefficient, and finally the output control unit adjusts the pulse duty cycle of the laser or switches to the position synchronous output mode according to the processed pulse modulation coefficient or spatial dispersion trigger signal, driving the laser and cutting head to perform precise physical processing.

[0033] As shown in Fig. 2 , the vertical coordinate represents the response time in ms, and the horizontal coordinate covers the piercing start response, sharp corner switching response, and heat accumulation response, the column chart filled with horizontal stripes represents the test data of traditional P-V control, and the column chart filled with diagonal stripes represents the test data of the system of the present application, through the intuitive comparison of the height difference between the two, it can be found that the system response delay of the system of the present application is lower than that of the traditional control strategy when processing the start after static piercing, the sharp corner switching of complex contour, and the heat accumulation suppression of long-time processing; as shown in Fig. 3 , the left digital calculation domain is located inside the industrial control host computer, and is divided from top to bottom into a trajectory prediction layer responsible for instruction analysis, virtual trajectory injection, and density calculation, a strategy decision layer responsible for parameter adjustment, modulation domain switching, and cooling insertion, a signal sensing layer responsible for high-frequency noise extraction and dispersion analysis, and an output interface layer responsible for pulse control and position synchronous output, the right physical execution domain corresponds to the machine tool hardware facilities, including an energy output subsystem composed of a fiber laser and a pulse controller, a motion execution subsystem composed of a servo driver, a servo motor, and an encoder, and an environment sensing subsystem composed of a height sensor and a capacitive feedback probe, the two domains interact through a high-speed real-time communication bus for data interaction of state data uplink and control instruction downlink, and the signal sensing layer and the strategy decision layer realize dynamic correction of control parameters through a closed-loop adaptive link.

[0034] Example 4: This embodiment solves the problem of overburning of kinematic singularities for complex topological structures such as irregular and continuous sawtooth edges in precision sheet metal processing, the workpiece to be processed is a thin-walled stator lamination with a continuous sawtooth edge, the edge has a large number of small-radius ( ) are connected, when the cutting head traverses these sharp corner regions, the servo axis feed speed will inevitably experience a process of deceleration to zero and then acceleration due to kinematic constraints, even if the laser power decreases linearly with speed, the number of laser pulses stacked in unit space distance will tend to infinity as the speed approaches zero; in view of the above problems, the embodiment of the present application adopts a modulation domain dynamic switching strategy based on local energy density index and geometric curvature characteristic double constraints, the specific control process is as follows: the instruction analysis unit calculates the geometric curvature characteristic of each place in the track when reading the instruction sequence in the pre-reading buffer, and sets the preset curvature threshold value as Comparison is made, and all sharp corner feature sections are identified.

[0035] During the machining process, the parameter adjustment unit monitors the current local energy density index and geometric curvature characteristic in real time, when it is detected that both of them exceed the preset threshold value at the same time, the local energy density index is at a high level and the geometric curvature characteristic exceeds , the system determines that the current is in the singular point working condition of high heat accumulation and low speed motion, and generates a spatial discrete trigger signal, in response to the spatial discrete trigger signal, the output control unit executes the dynamic switching of the modulation domain, the system shields the time-based clock trigger signal inside the laser, and instead establishes a direct hardware mapping with the servo motor encoder feedback pulse, and switches the control mode to the position synchronous output mode, in the position synchronous output mode, the triggering of the laser pulse is strictly locked to the physical displacement of the cutting head, and is set to trigger a laser pulse every fixed space step ; this mechanism ensures that no matter how low the actual motion speed of the cutting head is at the sharp corner, the laser energy density acting on the workpiece per unit length remains constant, eliminating energy accumulation caused by speed fluctuations, the test results show that after adopting the spatial domain modulation strategy, the sharp corner profile of the jagged edge is clear and sharp, there is no over-melted round corner, and the heat affected zone width is highly consistent with the straight line segment, and the sharp corner profile error is controlled within .

[0036] Embodiment 5: In this embodiment, a standardized on-site deployment pre-calibration procedure is constructed, before formal machining, the operator uses the automatic calibration function of the system to perform a set of standard test matrix in the waste area of the to-be-machined plate, which includes short line cutting tasks under different speed and power combinations, the system collects and analyzes the capacitance signal noise characteristics of the cutting head height sensor feedback in real time through the signal feature analysis unit, automatically establishes the noise-thermal state benchmark mapping table of the current batch of materials, and uses it as the input benchmark of the global gain calibration logic in the parameter adjustment unit, so that the system can dynamically adjust the calculation weight of the local energy density index according to the measured material response characteristics.

[0037] And for the problem of offline data mismatching real-time working condition in the above scenarios, the embodiment further introduces offline calibration and data filling procedures. In the system initialization stage, high-precision thermal simulation software is used to simulate the thermal field of a series of typical topological structures such as right angle, acute angle, circular arc and narrow bridge, to build an offline database containing the multi-dimensional nonlinear relationship between geometric curvature, cutting speed, laser power and local thermal accumulation index, and after strict experimental verification and correction, the offline database is solidified into the lookup table of the density calculation unit. In the real-time processing process, the system quickly obtains the theoretical thermal response value under the current working condition by lookup table method, and combines the real-time feedback data obtained by the foregoing online calibration to make microsecond-level correction to the prediction result.

[0038] Embodiment 6: This embodiment constructs a standardized system deployment pre-calibration procedure. The procedure is designed as the initialization step executed when the system is powered on for the first time or when the material batch is replaced. After the procedure is started, the control system automatically generates and executes a set of orthogonal cutting test matrix covering different speed intervals ( to ) and power levels ( to ). During the execution of each test section, the density calculation unit records the theoretical energy input set by the instruction in real time, while the signal feature analysis unit synchronously collects the high-frequency noise component of the height sensor capacitor signal, calculates the statistical variance value, and the system automatically calibrates the noise-thermal state reference curve under the current material batch by fitting the nonlinear mapping relationship between the noise variance and the theoretical energy density by the least square method, and solidifies it as the reference model of the global gain calibration logic in the parameter adjustment unit, so that the system can quantitatively calculate the global attenuation coefficient according to the deviation of the measured noise from the reference in subsequent processing, thereby automatically compensating for the thermal response deviation caused by the fluctuation of material properties without human intervention.

[0039] In addition, for the servo following lag problem that may exist at the kinematic singularity, the embodiment also integrates a dynamic parameter optimization subroutine for the position synchronous output mode (PSO). In the calibration stage, the system controls the cutting head to traverse the standard right-angle test spline at a very low speed (for example, ), and uses the encoder feedback data to monitor the position deviation of each axis in real time. The system automatically adjusts the spatial trigger step distance and laser switch delay parameters in the PSO mode according to the preset profile error tolerance such as , until the coincidence degree of the measured trajectory and the instructed trajectory meets the accuracy requirement.

[0040] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application.

[0041] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. An adaptive control system for precision sheet metal laser cutting process parameters, characterized in that, The system includes an instruction parsing unit, a density calculation unit, a parameter adjustment unit, and an output control unit. The instruction parsing unit reads the instruction sequence from the pre-read buffer of the CNC machining program and extracts the geometric coordinates and feed rate. It constructs a four-dimensional data stream for the trajectory nodes in the instruction sequence based on relative timestamps and identifies the static piercing action instructions in the instruction sequence. The density calculation unit constructs a virtual spatiotemporal sliding window centered on the target trajectory point to be processed, executes the virtual trajectory injection logic, calculates the equivalent virtual trajectory length based on the perforation energy parameters set by the static perforation action command and the preset standard line energy density, constructs a virtual trajectory data packet with an equivalent virtual trajectory length and spatial coordinates anchored to the perforation position, and injects it into the calculation queue of the spatiotemporal sliding window. The density calculation unit filters the effective laser opening trajectory segments and virtual trajectory data packets that fall into the spatiotemporal sliding window, performs attenuation weighted accumulation based on time difference, and generates a local energy density index characterizing the local heat accumulation level of the target trajectory point. The parameter adjustment unit generates basic pulse modulation coefficients based on the local energy density index according to the preset density parameter mapping relationship, and executes modulation domain switching logic. When the local energy density index exceeds the first threshold and the geometric curvature characteristics of the target trajectory point exceed the second threshold, a spatial discrete trigger signal is generated. The output control unit uses the basic pulse modulation coefficient to control the pulse duty cycle of the laser in real time, and responds to the spatial discrete trigger signal to switch the control mode of the laser from the pulse width modulation mode based on the time period to the position synchronous output mode based on the axis motion distance, so as to lock the number of laser pulses per unit spatial distance.

2. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 1, characterized in that, When executing the virtual trajectory injection logic, the density calculation unit calculates the equivalent virtual trajectory length using the following calculation rules: ,in, Represents the equivalent virtual trajectory length. This represents the piercing power set by the static piercing action command. This represents the dwell time set by the static perforation action command. This represents the preset standard line energy density; the density calculation unit sets the time attribute of the generated virtual trajectory data packet to the start time immediately adjacent to the subsequent cutting action.

3. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 1, characterized in that, The density calculation unit also executes the thermal conduction boundary correction logic. When constructing the spatiotemporal sliding window, it identifies historical trajectory points in the instruction sequence whose processing status is marked as completed, and calculates the topological barrier density of the completed historical trajectory points within the spatiotemporal sliding window. The density calculation unit generates the thermal barrier gain coefficient based on the topological barrier density and uses the thermal barrier gain coefficient to perform positive weighted correction on the local energy density index.

4. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 1, characterized in that, The system also includes a signal feature analysis unit connected to the laser cutting head height adjustment sensor; The signal feature analysis unit extracts the high-frequency noise component from the capacitance signal of the height sensor and calculates the statistical dispersion index of the high-frequency noise component within a unit time window; when the statistical dispersion index exceeds the preset stability threshold, the parameter adjustment unit generates a global attenuation coefficient and performs a secondary weighted correction on the basic pulse modulation coefficient.

5. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 1, characterized in that, The instruction parsing unit calculates the geometric curvature characteristics by parsing the angle between adjacent trajectory vectors; the modulation domain switching logic in the parameter adjustment unit is configured with a hysteresis comparison function, which triggers the operation of releasing the spatial discrete trigger signal only when the geometric curvature characteristics fall back to a safe hysteresis value below the second threshold, so that the control mode of the laser is restored to the pulse width modulation mode based on the time period.

6. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 1, characterized in that, When calculating the local energy density index, the density calculation unit applies a time decay weight function that monotonically decreases with increasing time difference. The decay rate constant of the time decay weight function is set based on the thermal diffusivity of the processed material. The density calculation unit only includes effective laser activation trajectory segments whose time difference with the target trajectory point is less than the thermal dissipation time constant in the weighted cumulative calculation.

7. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 1, characterized in that, The parameter adjustment unit also executes cooling insertion logic. When the calculated local energy density index exceeds the preset limit threshold, it generates a dwell command and inserts it before the processing command at the target trajectory point. The output control unit responds to the dwell command by controlling the laser to turn off the laser output and maintaining the auxiliary gas output until the real-time local energy density index calculated by the density calculation unit drops to the allowable threshold.

8. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 4, characterized in that, The signal feature analysis unit includes a high-pass filter and a variance calculation module. The high-pass filter filters out the DC and low-frequency components that characterize the change in cutting head height in the capacitor signal, while retaining the high-frequency AC components that characterize the fluctuation of the plasma cloud. The variance calculation module performs sliding window variance calculation on the retained high-frequency AC components to obtain the statistical dispersion index.

9. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 1, characterized in that, The virtual trajectory data packet contains spatial coordinates, timestamps, and laser on status bits that are consistent with the actual processing trajectory data structure, but the corresponding physical axis motion speed is zero. When processing the virtual trajectory data packet, the density calculation unit treats it as a physical trajectory segment with non-zero energy density and performs thermal accumulation contribution calculation.

10. The adaptive control system for precision sheet metal laser cutting process parameters according to claim 1, characterized in that, In position synchronization output mode, the output control unit shields the clock trigger signal inside the laser and establishes a hardware mapping connection with the feedback pulse of the servo motor encoder, triggering a laser pulse output once every time the cutting head moves a preset fixed spatial step.

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