A laser head servo control method and system in a laser cutting process

Abstract

The application discloses a laser head servo control method and system in a laser cutting process, and the method comprises the following steps: setting a calibration characteristic curve of a distance sensor and controlling a Z-axis servo motor to calibrate; setting a precision parameter of a cutting height, setting a speed and acceleration / deceleration of the Z-axis servo motor according to a distance difference; and calculating the speed and acceleration / deceleration setting value of the Z-axis servo motor when the laser head enters and exits the edge of the material to be cut. The application realizes smooth control of the cutting height in the cutting process, carries out accurate calibration of the distance sensor, reduces the influence of external interference on the sensing distance by filtering, considers the whole cutting process from when the laser head enters the edge of the material to be cut to when the laser head exits the edge of the material to be cut, and respectively adopts different speed and acceleration / deceleration setting values, so that the cutting height is smoothly and quickly controlled in the whole cutting process.

Description

Technical Field

[0001] This invention relates to laser cutting control technology, and more particularly to a laser head follow-up control method and system in the laser cutting process. Background Technology

[0002] With the rapid development of the processing industry, laser cutting machines have been used more and more widely. They can achieve fast, accurate and efficient cutting of metal materials such as stainless steel, carbon steel, aluminum plates, galvanized plates, and iron plates.

[0003] To achieve good cutting results, all process parameters must be kept at their optimized values ​​during laser cutting. Cutting height is a particularly important parameter; improper settings can significantly impact the cutting effect, causing slag buildup, nodules, or even failure to cut. Therefore, maintaining a stable cutting height is crucial during laser cutting.

[0004] The thickness of metal sheets often fluctuates in the width direction. To maintain a stable cutting height, most mainstream laser heads are equipped with non-contact distance sensors that measure the distance between the laser head and the surface of the metal sheet. For example, the distance sensor of a certain brand of laser head has a measurement range of 0.0–10.0 mm, corresponding to an output voltage of 0–10V. The ratio between the measured output voltage and the corresponding distance value is stored in the laser head's height adjuster. This ratio is affected by the measured material; therefore, calibration is necessary after the initial measurement or after changing to a different specification or type of steel sheet. During calibration, the laser head will contact the steel sheet, at which point the laser head's height adjuster will emit a contact signal. If the laser head is too far from the steel sheet, exceeding the 10.0 mm measurement range, the laser head's height adjuster will emit an out-of-measurement-range signal. Additionally, the laser head is mounted on a vertically movable axis, and a PLC (Programmable Logic Controller) controls a servo motor to achieve the vertical movement of the axis, thus providing the hardware conditions for laser head follow-up control.

[0005] Because there is a certain error in the cutting plate width data, to ensure that the cutting plate can be completely cut, the laser and cooling gas need to be activated before the laser head reaches the edge of the cutting plate. Similarly, after the cutting plate is finished, even though the laser head has already moved beyond the other side of the cutting plate, the laser and cooling gas must remain on for a short period of time. Therefore, during the cutting process, there will be one instance of the laser head entering the edge of the cutting plate and another instance of the laser head exiting the edge of the cutting plate. The laser head servo function is enabled during both of these processes. At this time, the sensing distance of the laser head outside the cutting plate range will exceed the measurement range. Furthermore, based on actual observation, there is a transition time of approximately two sampling cycles for the sensing distance. Taking the laser head exiting the edge of the cutting plate as an example, the sensing distance first changes from near the cutting height to a relatively large value within the measurement range, then reaches near the measurement range in the next sampling cycle, and then exceeds the measurement range in the next sampling cycle. To address this situation, the servo motor's movement must be carefully controlled when the laser head enters and exits the edge of the cutting plate; otherwise, the laser head may descend rapidly, causing equipment damage. Summary of the Invention

[0006] The main objective of this invention is to provide a laser head follow-up control method and system for laser cutting, which can improve the stability of cutting control during high-difficulty cutting processes.

[0007] The technical solution adopted in this invention is: a laser head follow-up control method in the laser cutting process, wherein the laser head is controlled to move in the height direction by a Z-axis servo motor and to move in the cutting direction by a Y-axis servo motor; the method includes the following steps:

[0008] Calibration of S1 and Z-axis servo motors:

[0009] A calibration characteristic curve for the distance sensor is set, and the Z-axis servo motor is controlled to perform calibration based on the calibration characteristic curve. The distance sensor is used to measure the distance between the laser head nozzle and the upper surface of the material to be cut. Several feature points are set within the range of the distance sensor, and the calibration characteristic curve is composed of the positions of all feature points.

[0010] S2. Calculate and set the operating parameters of the Z-axis servo motor:

[0011] 2.1 When the laser head enters the edge of the material to be cut:

[0012] Before the laser head enters the edge of the material to be cut, the distance sensor measurement value exceeds the range, so the Z-axis servo motor remains stationary. The sampling time when the laser head enters the edge of the material to be cut and the next sampling time are determined. Based on the cutting height value measured by the distance sensor and the cutting height setting value, the proportional-integral controller is used to calculate the action speed of the Z-axis servo motor with a preset small proportional coefficient. The calculated speed is then limited by a preset small limit value to obtain a second speed setting value. Based on the second speed setting value and the Z-axis servo motor's own parameters, a second acceleration / deceleration setting value is determined as the operating parameter of the Z-axis servo motor when the laser head enters the edge of the material to be cut.

[0013] 2.2 During the cutting process:

[0014] After determining the two sampling moments when the laser head enters the edge of the material to be cut, the first speed setpoint is calculated by increasing the proportional coefficient and the speed limit value using the proportional-integral controller. Based on the first speed setpoint and the parameters of the Z-axis servo motor, the first acceleration / deceleration setpoint is determined. The first speed setpoint and the first acceleration / deceleration setpoint are used as the operating parameters of the Z-axis servo motor during the cutting process.

[0015] During the cutting process, the movement in the cutting direction is controlled by a Y-axis servo motor;

[0016] 2.3 When the laser head exits from the edge of the material to be cut:

[0017] The third speed setting value is set to 0, and the third deceleration setting value is set to the maximum value, which are used as the operating parameters of the Z-axis servo motor when the laser head exits from the edge of the material to be cut;

[0018] S3. Control the Z-axis servo motor according to the operating parameters set in S2, and drive the laser head to move during cutting.

[0019] Using the above method, the range of the distance sensor is a fixed value, and the cutting height range is the distance between the laser head nozzle and the upper surface of the material to be cut. The range is given according to the process requirements and is within the range of the distance sensor. Feature points are selected within the range of the distance sensor, and the number of feature points located within the cutting height range accounts for more than half of the total number of feature points.

[0020] The calibration process in S1, as described above, is as follows:

[0021] The Z-axis servo motor descends at a preset low speed until the laser head nozzle contacts the upper surface of the material to be cut and stops. Then, the Z-axis servo motor is controlled to raise the laser head to the feature point with the greatest distance from the upper surface of the material to be cut. After reaching the position, the height controller records the position and the corresponding voltage value fed back by the distance sensor. Then, according to the calibration feature curve, the Z-axis servo motor is controlled to reach each feature point from high to low in sequence, and the position and corresponding voltage value of each feature point are recorded. Finally, the Z-axis servo motor is controlled to lift up at a preset fast speed, and the calibration is completed.

[0022] Using the above method, section 2.1 determines whether the laser head has entered the edge of the material to be cut by means of the following:

[0023] If at a certain sampling time n, the distance value obtained by the distance sensor is greater than the range of the distance sensor, and the distance value obtained at time n+1 is less than or equal to the range, it is determined that the laser head has entered the edge of the steel plate.

[0024] Using the method described above, section 2.3 determines whether the laser head exits from the edge of the material to be cut in the following way:

[0025] If at a certain sampling time m, the distance value obtained by the distance sensor fluctuates within a certain range of the cutting height setting value, and the distance value obtained at the next sampling time m+1 exceeds the preset value that is much greater than the cutting height setting value, then it is determined that the laser head exits from the edge of the material to be cut.

[0026] A laser head follow-up control system includes a laser head with a built-in distance sensor for sensing the distance between the laser nozzle and the material to be cut. The laser head is mounted on a Z-axis servo motor and moves along a Z-axis track along the height direction. The Z-axis track is mounted on a Y-axis servo motor, so that the laser head, Z-axis servo motor, and Z-axis track together move along a Y-axis track along the cutting direction. The system also includes a control unit for controlling the movement trajectories of the Z-axis and Y-axis servo motors based on the distance values ​​collected by the distance sensor, thereby realizing the laser head follow-up control method according to any one of claims 1 to 5.

[0027] According to the above system, the system also includes a height adjuster for distance sensor calibration. The distance sensor and the height adjuster are connected via optical fiber, and the height adjuster is electrically connected to the control unit.

[0028] According to the above system, the control unit includes a PLC controller and a servo amplifier. The PLC controller controls the Z-axis servo motor and the Y-axis servo motor through the servo amplifier.

[0029] An electronic device includes a memory, a controller, and a controller program stored in the memory and executable on the controller, wherein the controller implements the steps of the laser head follow-up control method described above when executing the controller program.

[0030] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a controller, implements the steps of the laser head follow-up control method described above.

[0031] The beneficial effects of this invention are as follows: by calibrating the laser head distance sensor, the sensed distance value is made more accurate; considering the transition process when the laser head enters the edge of the material to be cut, the proportional coefficient, speed limit, and acceleration / deceleration of the Z-axis servo motor are reduced, making the transition process smoother and reducing overshoot; considering the transition process when the laser head leaves the edge of the material to be cut, the deceleration setting value of the Z-axis servo motor is increased to stop the servo motor as quickly as possible; during the middle of the cutting process, a moderate proportional coefficient, speed limit, and acceleration / deceleration are used, allowing the Z-axis servo motor to quickly and accurately follow the fluctuations in the thickness of the material to be cut, maintaining a stable cutting height, thus solving the problem of cutting height control in laser cutting. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0033] Figure 1 This is a flowchart of a method according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram of an embodiment of the present invention.

[0035] In the diagram: 1-Y-axis track, 2-Y-axis servo motor, 3-absolute encoder, 4-Z-axis track, 5-servo amplifier, 6-PLC, 7-laser head, 8-distance sensor, 9-laser nozzle, 10-Z-axis servo motor, 11-absolute encoder, 12-height adjuster, 13-steel plate, 14-transfer roller conveyor. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] like Figure 1 As shown, taking steel plate cutting as an example, this invention provides a laser head follow-up control method in the laser cutting process. The laser head is controlled to move in the height direction by a Z-axis servo motor and to move in the cutting direction by a Y-axis servo motor. This method includes the following steps:

[0038] Calibration of S1 and Z-axis servo motors:

[0039] Before cutting steel plates, the laser head distance sensor must be calibrated. Only after calibration can the distance sensor's measurement values ​​be accurate and effective. The accuracy of the laser head follow-up control directly depends on the measurement accuracy of the distance sensor.

[0040] A calibration characteristic curve for the distance sensor is set, and the Z-axis servo motor is controlled to perform calibration based on the calibration characteristic curve. The distance sensor is used to measure the distance between the laser head and the upper surface of the material to be cut. Several feature points are set within the range of the distance sensor, and the calibration characteristic curve is composed of the positions of all feature points.

[0041] The distance sensor has a fixed range. The cutting height range is the distance between the laser head nozzle and the upper surface of the material to be cut, and this range is given according to process requirements. Within the range of the distance sensor, feature points are selected, and the number of feature points located within the cutting height range accounts for more than half of all feature points. The height adjustment range of the Z-axis servo motor is approximately 140mm, while the distance sensor's range is 10mm. The distance sensor measures the distance from the laser head nozzle to the upper surface of the material to be cut, excluding the thickness of the material. During the cutting process, the sensed distance still represents the distance from the laser head nozzle to the upper surface of the material to be cut; even if the material has been cut through, it does not affect the measurement, as the height adjuster will automatically handle this.

[0042] To achieve high-precision calibration, this embodiment employs a calibration method using 16 feature points within the distance sensor's measurement range. These 16 feature points form a characteristic curve. Considering that the cutting height of laser cutting machines is typically within 2.0 mm, more feature points are set below 2.0 mm, while feature points in the range of 2.0 mm to 10.0 mm are more sparsely distributed. In this embodiment, the selected feature points are:

[0043] [0.2,0.5,0.7,1.0,1.2,1.5,1.8,2.0,2.5,3.0,4.0,5.0,6.0,7.0,8.0,10.0]mm

[0044] The calibration process is as follows:

[0045] The Z-axis servo motor descends at a preset low speed until the laser head nozzle contacts the upper surface of the material to be cut and stops. Then, the Z-axis servo motor is controlled to raise the laser head to the feature point with the largest distance from the upper surface of the material to be cut (10.0 mm in this embodiment). After reaching the position, the height controller records the position and the corresponding voltage value fed back by the height controller. Then, according to the calibration feature curve, the Z-axis servo motor is controlled to reach each feature point from high to low in sequence, and the position and corresponding voltage value of each feature point are recorded. Finally, the Z-axis servo motor is controlled to lift up quickly at a preset speed, and the calibration is completed.

[0046] The voltage value fed back by the distance sensor, for example, if the distance from the laser head nozzle to the surface of the steel plate is 2mm, then the voltage value fed back is, for example, 2V. The height adjuster records the correspondence between the voltage value fed back and the distance. When in use, the height adjuster can calculate the sensing distance value based on the voltage value fed back by the distance sensor and send it to the PLC for use.

[0047] After calibration, the distance sensor can output the sensed distance value. However, in actual use, the distance sensor will be affected by interference factors such as dust and fog in the field. In order to reduce the influence of interference, the sensed distance value needs to be filtered. Commonly used filtering circuits are first-order smoothing filter circuit and multi-point averaging filter. In this embodiment, multi-point averaging filter is used, that is, several adjacent sample values ​​are selected, averaged and then output.

[0048] S2. Calculate and set the operating parameters of the Z-axis servo motor:

[0049] The measurement of the sensing distance has a very small error, so a precision parameter needs to be set. Fluctuations within the precision parameter range are normal and do not require adjustment. In this embodiment, the Z-axis servo motor uses a speed control mode, where the PLC calculates the speed and acceleration / deceleration setpoints based on the distance difference and sends them to the Z-axis servo motor.

[0050] 2.1 When the laser head enters the edge of the material to be cut:

[0051] Before the laser head enters the edge of the material to be cut, the distance sensor measurement value exceeds the range, at which point the Z-axis servo motor remains stationary. The sampling time when the laser head enters the edge of the material and the next sampling time are determined. Based on the cutting height value measured by the distance sensor and the cutting height setpoint, a proportional-integral controller is used to calculate the Z-axis servo motor's operating speed with a preset small proportional coefficient. The calculated speed is then limited by a preset small limit value to obtain a second speed setpoint. Based on the second speed setpoint and the Z-axis servo motor's own parameters, a second acceleration / deceleration setpoint is determined, which serves as the Z-axis servo motor's operating parameters when the laser head enters the edge of the material to be cut.

[0052] Suppose that at a certain sampling time n, the sensing distance value is greater than the range and at time n+1 the sensing distance value is less than the range, it is determined that the laser head has entered the edge of the steel plate. At this time, the sensing distance changes drastically. In order to reduce the overshoot of the follow-up control, the proportional coefficient of the proportional controller should be reduced, and the acceleration setting value and speed limit value of the Z-axis servo motor should also be set to a lower value.

[0053] Specifically, in this embodiment, the two sampling times n+1 and n+2 when the laser head enters the edge of the steel plate are determined, the scaling factor is set to 1.0, the integration time is set to 500ms, and the acceleration / deceleration of the Z-axis servo motor is set to 200mm / s. 2 The speed limit range is also reduced to 0.0–3.0 mm / s.

[0054] 2.2 During the cutting process:

[0055] After determining the two sampling moments when the laser head enters the edge of the material to be cut, the first speed setpoint is calculated by increasing the proportional coefficient and the speed limit value using the proportional-integral controller. Based on the first speed setpoint and the parameters of the Z-axis servo motor, the first acceleration / deceleration setpoint is determined. The first speed setpoint and the first acceleration / deceleration setpoint are used as the operating parameters of the Z-axis servo motor during the cutting process.

[0056] In this embodiment, the distance measured by the laser head distance sensor is denoted as H. act Note that the distance measurement value will fluctuate slightly when the distance remains constant. Based on actual observation, the fluctuation range is within ±0.015mm. Therefore, the accuracy parameter is set to P. H = 0.015mm. Find the current thickness of the steel plate cutting height setting in the process parameter table, and record it as H. cu,SP The difference between the two is the distance that needs to be adjusted.

[0057] Z Adj =H act -H cut,SP

[0058] If the distance Z to be adjusted Adj If the distance is within the accuracy parameter range, no adjustment is required; if the distance to be adjusted is outside the accuracy parameter range, the above proportional-integral controller is used to calculate the motor speed according to the adjustment distance, and then the speed is limited to obtain the final first speed setting value.

[0059]

[0060] In the formula, V z,SP () and V z,SP(-1) represents the first speed setpoint of the Z-axis servo motor at the current and previous moments, respectively. Lim represents the limiting element, and the specific limiting value is set according to the parameters of the Z-axis servo motor. K P T is the proportionality coefficient. S T is the sampling time of the PLC controller. I Z is the integration time parameter. Adj () and Z Adj (-1) represents the distance the Z-axis servo motor needs to adjust at the current and previous moments, respectively. In this embodiment, the given speed limit range is 0.0~4.0mm / s, and the proportional coefficient K P Set to 1.6, integration time T I Set to 500ms.

[0061] At this point, the acceleration and deceleration are set to appropriate values, specifically based on the parameters of the Z-axis servo motor. In this embodiment, the first acceleration and deceleration are set as follows:

[0062] Acc SP =ec SP =300 / s 2

[0063] In the formula, Acc SP The first acceleration setpoint, Dec SP This is the first deceleration setting value.

[0064] During the cutting process, the movement in the cutting direction is controlled by a Y-axis servo motor.

[0065] 2.3 When the laser head exits from the edge of the material to be cut:

[0066] The third speed setting value is set to 0, and the third deceleration setting value is set to the maximum value, which are used as the operating parameters of the Z-axis servo motor when the laser head exits from the edge of the material to be cut.

[0067] During the cutting process, the laser head moves from one side of the steel plate to the other. The sensing distance fluctuates around the set cutting height until the laser head reaches the edge of the steel plate, at which point the sensing distance suddenly increases and exceeds the range after two sampling moments. If at a certain sampling moment *m*, the sensing distance is less than 2.0 mm, and at moment *m+1*, the sensing distance is greater than 2.0 mm, indicating that the laser head has moved out of the edge of the steel plate at this moment. The change in sensing distance between these two sampling moments is relatively drastic, and the Z-axis servo motor should stop as soon as possible. The Z-axis servo motor speed should be set to 0.0 mm / s, and the deceleration set to a relatively high value.

[0068] Specifically, in this embodiment, the two sampling times m+1 and m+2 when the laser head exits the edge of the steel plate are determined. The speed of the Z-axis servo motor is set to 0.0 mm / s, and the deceleration is set to 500 / s. 2 Once the Z-axis servo motor stops, it remains stationary until the next process begins.

[0069] S3. Control the Z-axis servo motor according to the operating parameters set in S2, and drive the laser head to move during cutting.

[0070] The laser head follow-up control method provided in this embodiment of the invention first calibrates the laser head distance sensor. After calibration, a relatively accurate sensing distance value is obtained. Then, the measured distance value is filtered to reduce the influence of interference. Accuracy parameters are set according to the accuracy of the distance measurement value. The sensing distance is compared with the cutting height setting value to obtain the position difference. The PLC calculates the speed and acceleration / deceleration of the Z-axis servo motor during the intermediate cutting process based on the position difference. Finally, the calculation method for the speed and acceleration / deceleration of the Z-axis servo motor when the laser head enters and exits the edge of the steel plate is given. This completes the laser head follow-up control during the cutting process.

[0071] This invention also provides a laser head follow-up control system for implementing the above-described method embodiments, such as... Figure 2As shown, the conveyor roller 14 transports the steel plate 13 to the cutting area to await cutting. The system includes a PLC controller 6, a servo amplifier 5, a height adjuster 12, a laser head 7, a Y-axis servo motor 2 (the axis moving in the cutting direction) and a Z-axis servo motor 10 (the axis moving in the height direction), a Y-axis track 1, and a Z-axis track 4. The Y-axis servo motor 2 and the Z-axis servo motor 10 are used to move the laser head on the Y-axis track (the track moving in the cutting direction) 1 and the Z-axis track (the track moving in the height direction) 4. The Y-axis servo motor 2 and the Z-axis servo motor 10 are also equipped with absolute encoders 3 and 11, respectively, to measure the actual position values ​​of the Y-axis servo motor 2 and the Z-axis servo motor 10. The laser head 7 has a built-in distance sensor 8, which can sense the distance between the laser nozzle 9 and the steel plate 13. Distance sensor 8 and height adjuster 12 are connected via optical fiber. PLC controller 6 reads the sensed distance measurement value from height adjuster 12, and the absolute encoder reading is also fed into the PLC controller. PLC controller 6 sends instructions to servo amplifier, which controls the movement of Y-axis and Z-axis servo motors. The PLC controller first controls the Y-axis and Z-axis servo motors to calibrate the distance sensor. After calibration, cutting is initiated. The Z-axis servo motor is controlled to lower the laser head close to the steel plate surface, and then the Y-axis servo motor is controlled to move at a constant speed along the width of the steel plate. During laser cutting, the Z-axis servo motor continuously adjusts according to the sensed distance value, maintaining a stable cutting height until cutting is complete. All laser head follow-up control functions are programmed and implemented in PLC controller 6.

[0072] In summary, the laser head servo control method and system provided by this invention achieve high-precision servo control of the laser head during the laser cutting process. A precise calibration method for the laser head distance sensor is presented, and filtering is used to reduce the influence of external interference, making the sensed distance value more accurate. The transition process when the laser head enters the edge of the steel plate is considered, and the proportional coefficient, speed limit, and acceleration / deceleration are reduced to make the transition process smoother and reduce overshoot. The transition process when the laser head exits the edge of the steel plate is considered, and the deceleration setpoint is increased to stop the servo motor as quickly as possible. During the intermediate cutting process, a moderate proportional coefficient, speed limit, and acceleration / deceleration are used to allow the Z-axis servo motor to quickly and accurately follow the fluctuations in the steel plate thickness, maintaining a stable cutting height and solving the problem of cutting height control during laser cutting.

[0073] An electronic device includes a memory, a controller, and a controller program stored in the memory and executable on the controller, wherein the controller implements the steps of the laser head follow-up control method described above when executing the controller program.

[0074] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a controller, implements the steps of the laser head follow-up control method described above.

[0075] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for controlling the servo motion of a laser head during laser cutting, characterized in that, The laser head is controlled to move in the height direction by a Z-axis servo motor and to move in the cutting direction by a Y-axis servo motor; this method includes the following steps: Calibration of S1 and Z-axis servo motors: A calibration characteristic curve for the distance sensor is set, and the Z-axis servo motor is controlled to perform calibration based on the calibration characteristic curve. The distance sensor is used to measure the distance between the laser head and the upper surface of the material to be cut. Several feature points are set within the measurement range of the distance sensor, and the calibration characteristic curve is composed of the positions of all feature points. The calibration process is as follows: The Z-axis servo motor descends at a preset low speed until the laser head nozzle contacts the material to be cut and stops; then the Z-axis servo motor is controlled to raise the laser head to the feature point with the greatest distance from the material to be cut, and after it is in place, it waits for the height controller to record the position and the corresponding voltage value fed back by the distance sensor. Next, following the calibration characteristic curve, control the Z-axis servo motor to reach each feature point sequentially from high to low, and record the position and corresponding voltage value of each feature point; finally, control the Z-axis servo motor to lift up quickly at a preset speed, and the calibration is completed. S2. Calculate and set the operating parameters of the Z-axis servo motor: 2.

1. Cutting starts: The adjustment distance of the laser head is calculated based on the cutting height value measured by the distance sensor and the cutting height setting value. The precision range of the cutting height is set. Based on the calculated adjustment distance of the laser head and the preset precision range of the cutting height, a proportional-integral controller is used to calculate the motor speed with a certain proportional coefficient. After limiting the motor speed, the first speed setting value is obtained. Based on the first speed setting value and the parameters of the Z-axis servo motor, the first acceleration / deceleration setting value is determined. The first speed setting value and the first acceleration / deceleration setting value are used as the operating parameters of the Z-axis servo motor when cutting is just started. During the cutting process, the movement in the cutting direction is controlled by a Y-axis servo motor; 2.2 When the laser head enters the edge of the material to be cut: The proportional coefficient of the proportional-integral controller is reduced, and the amplitude is limited to obtain the second speed setting value. Based on the second speed setting value and the parameters of the Z-axis servo motor, the second acceleration / deceleration setting value is determined as the operating parameter of the Z-axis servo motor when the laser head enters the edge of the material to be cut. 2.3 When the laser head exits from the edge of the material to be cut: The third speed setting value is set to 0, and the third deceleration setting value is set to the maximum value, which are used as the operating parameters of the Z-axis servo motor when the laser head exits from the edge of the material to be cut; S3. Control the Z-axis servo motor according to the operating parameters set in S2, and drive the laser head to move during cutting.

2. The laser head follow-up control method according to claim 1, characterized in that, The range of the distance sensor is the distance between the laser head at its highest position and the upper surface of the material to be cut, and the cutting height range is the distance from the upper surface to the lower surface of the material to be cut; the number of feature points selected within the laser head cutting height range is greater than the number of feature points within the range of other Z-axis servo motors.

3. The laser head follow-up control method according to claim 1, characterized in that, The method described in 2.2 determines whether the laser head has entered the edge of the material to be cut by the following method: If at a certain sampling time n, the distance value obtained by the distance sensor is greater than the range of the distance sensor, and the distance value obtained at time n+1 is less than or equal to the range, it is determined that the laser head has entered the edge of the steel plate.

4. The laser head follow-up control method according to claim 1, characterized in that, The method described in 2.3 determines whether the laser head exits from the edge of the material to be cut in the following way: If at a certain sampling time m, the distance value obtained by the distance sensor fluctuates within a certain range of the cutting height setting value, and the distance value obtained at the next sampling time m+1 exceeds the preset value that is much greater than the cutting height setting value, then it is determined that the laser head exits from the edge of the material to be cut.

5. A laser head follow-up control system, characterized in that, This system includes a laser head, which has a built-in distance sensor for sensing the distance between the laser nozzle and the material to be cut. The laser head is mounted on a Z-axis servo motor and moves along the Z-axis track set along the height direction with the Z-axis servo motor. The Z-axis track is mounted on the Y-axis servo motor, so that the laser head, the Z-axis servo motor and the Z-axis track together move along the Y-axis track set along the cutting direction with the Y-axis servo motor; it also includes a control unit, which controls the movement trajectory of the Z-axis servo motor and the Y-axis servo motor according to the distance value collected by the distance sensor, thereby realizing the laser head follow-up control method according to any one of claims 1 to 4.

6. The laser head follow-up control system according to claim 5, characterized in that, The system also includes a height adjuster for distance sensor calibration. The distance sensor and the height adjuster are connected via optical fiber, and the height adjuster is electrically connected to the control unit.

7. The laser head follow-up control system according to claim 5, characterized in that, The control unit includes a PLC controller and a servo amplifier. The PLC controller controls the Z-axis servo motor and the Y-axis servo motor through the servo amplifier.

8. An electronic device comprising a memory, a controller, and a controller program stored in the memory and executable on the controller, characterized in that: When the controller executes the controller program, it implements the steps of the laser head follow-up control method as described in any one of claims 1 to 4.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the controller, it implements the steps of the laser head follow-up control method according to any one of claims 1 to 4.

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