Flame induction laser cutting bed and control system

Abstract

The invention relates to the technical field of laser processing, in particular to a flame sensing laser head control system which comprises a laser cutting device, a flame sensing module, a height adjusting module and a main controller. The flame sensing module monitors flame signals in real time, the displacement sensor dynamically measures the vertical distance between the laser head and a workpiece, and the main controller adjusts the height of the laser head according to the signals and deals with abnormities. The laser cutting device can rapidly give an alarm and stop laser output when the flame is abnormal, the cutting height is dynamically adjusted to improve the machining precision, oscillation is reduced through an incremental PID algorithm, self-adaptive adjustment is achieved through fault recording, and the safety and the intelligent level of equipment are remarkably improved.

Description

Technical Field

[0001] The present invention mainly relates to the field of laser cutting, and in particular to a flame-sensing laser cutting machine and a control system. Background Art

[0002] With the widespread adoption of laser processing technology, flame sensing and the safety and precision control of laser cutting machines have become research hotspots. Especially in industrial scenarios like high-precision cutting and welding, avoiding safety hazards caused by accidental flames while maintaining a constant vertical distance between the laser head and the workpiece are key issues in improving equipment performance and operational safety.

[0003] A search revealed a laser sensing device and camera system with publication number CN115514923B, published on March 7, 2025. This patent protects the image acquisition device from laser damage by placing a laser sensing device in a preset area to detect the presence of laser light in advance and issue a warning signal. However, this technical solution primarily addresses the protection of the image acquisition device from laser damage and does not involve flame sensing, making it unable to address safety hazards caused by flame generation. Furthermore, the system lacks the ability to dynamically adjust the vertical distance between the laser head and the workpiece, making it difficult to meet the demand for precise distance control in complex processing scenarios.

[0004] After searching, the publication number CN116604202B is a method and system for accurately calibrating and controlling a laser head distance sensor, with a publication date of June 27, 2025. This patent ensures the measurement accuracy of the laser head near the working point by setting a calibration characteristic curve and a multi-point calibration method. However, this technical solution only focuses on the calibration accuracy of the laser head distance sensor and does not involve the flame sensing function, making it impossible to detect and respond to flame anomalies in a timely manner. At the same time, its calibration process relies on complex feature point settings and servo motor control, which may lead to a slow system response speed and has certain limitations in practical applications.

[0005] The above issues demonstrate that existing laser sensing and distance control technologies still have shortcomings in flame sensing, the ability to dynamically adjust the vertical distance between the laser head and the workpiece, and rapid response. Therefore, the present invention provides a flame-sensing laser cutting machine and control system designed to achieve real-time flame detection and automatic stop functions. Simultaneously, by driving the laser head up and down to maintain a constant vertical distance from the workpiece, this improves equipment safety and processing accuracy, meeting modern industry's demand for efficient, intelligent laser cutting machines. Summary of the Invention

[0006] To solve the above problems, the present invention adopts the following technical solutions.

[0007] The present invention provides a flame-sensing laser cutting bed, comprising a laser cutting component, wherein the laser cutting component comprises a laser reflection component and a laser head, wherein the laser head is located directly below the laser reflection component, and wherein the laser cutting component further comprises a vertical servo drive motor, a belt transmission mechanism and a screw slider mechanism, wherein the laser head is arranged on the screw slider mechanism, and a displacement sensor is arranged on the outside of the laser head through a bracket, wherein the displacement sensor is arranged at an angle, and its laser coincides with the cutting position of the laser head.

[0008] Furthermore, a photoelectric detector is provided on one side of the laser head close to the screw slider mechanism for detecting flame anomalies during the processing.

[0009] Utilizing the above-mentioned flame-sensing laser cutting bed, the present invention also provides a laser head control system, including a main controller, the vertical servo drive motor receives instructions from the main controller, and controls the screw slider mechanism to adjust the height of the laser head; the main controller receives signals from the flame sensing module and the displacement sensor, and processes them according to preset logic.

[0010] Furthermore, the photoelectric detector collects the light intensity signal of the flame radiation and converts it into a voltage signal; the main controller calculates its root mean square value after filtering the voltage signal, and compares the root mean square value with a preset flame signal trigger threshold.

[0011] Furthermore, the flame signal triggering threshold is 1.5 to 2 times the average value of the background light noise, and the average value of the background light noise is calculated by sampling the ambient light intensity through a photoelectric detector.

[0012] Furthermore, the displacement sensor transmits ultrasonic pulses and receives reflected signals, calculating the round-trip time of the ultrasonic waves to obtain the actual distance between the laser head and the workpiece surface; the main controller compares the measured value of the displacement sensor with the preset target vertical distance, and uses an incremental PID algorithm to calculate the adjustment amount to control the screw slider mechanism to adjust the height of the laser head.

[0013] Furthermore, the formula of the incremental PID algorithm is:

[0014] ΔU=K P ×e+K I ×∑e+K D ×(ee prev ),

[0015] Where ΔU is the adjustment amount, K P , K I , K D are proportional, integral and differential coefficients respectively, e is the current error, e prev is the error at the previous moment.

[0016] Furthermore, when the displacement sensor's measured value exceeds a preset range, the main controller identifies a height adjustment anomaly and attempts to recalibrate the displacement sensor's zero and full-scale values. If the calibration fails, the main controller prompts the user through the human-machine interface to check the displacement sensor's connection status or replace the sensor. If the photoelectric detector detects flame anomalies multiple times in a row, the main controller records the time interval and signal strength between each anomaly and analyzes whether there is a consistent pattern. If so, the main controller automatically adjusts the flame signal trigger threshold to adapt to different machining environments.

[0017] According to the above system, the field of view of the photodetector covers the working area of ​​the laser head; the displacement sensor is installed at the bottom of the laser head through an elastic clip, and its ultrasonic transmitting end is facing the workpiece surface; the main controller communicates with the photodetector and displacement sensor through the CAN bus to ensure the real-time and reliability of data transmission.

[0018] The system steps are summarized as follows:

[0019] S1. Initialize the system and set the flame sensing threshold, and calibrate the measurement range of the displacement sensor;

[0020] S2. Start the laser cutting operation. The flame sensing module monitors the flame signal in real time, and the displacement sensor synchronously collects the vertical distance between the laser head and the workpiece surface.

[0021] S3. When the flame sensing module detects that the flame signal intensity exceeds the preset threshold, the main controller triggers an alarm and stops the laser output;

[0022] S4. During the cutting process, the main controller dynamically adjusts the height of the laser head according to the measurement value of the displacement sensor to maintain the set vertical distance;

[0023] S5. If an abnormal situation occurs, the main controller records the fault information and performs corresponding recovery operations.

[0024] The beneficial effects of the present invention are:

[0025] This invention uses photoelectric detectors to achieve real-time monitoring of flame radiation signals in the processing area. Dynamic background noise sampling, adaptive threshold setting, and rapid calculation and comparison of the RMS value of the light intensity signal ensure detection sensitivity and low false alarm rate for abnormal flames. If the flame signal intensity exceeds the preset threshold, the main controller quickly triggers an audible and visual alarm and immediately shuts off the laser output, eliminating the fire hazard at the source. This shift in safety protection from passive defense to active intervention is particularly suitable for flammable material processing or high-power laser applications, greatly ensuring the safety of operators, equipment, and the environment.

[0026] The displacement sensor of the application can feed back the actual distance between the laser head and the workpiece surface in real time by accurately measuring the round trip time of ultrasonic pulses. The main controller uses the incremental PID control algorithm to dynamically calculate and output accurate motor adjustment instructions based on the deviation between the measured value and the target vertical distance. The system oscillation is suppressed, the laser head height is quickly, smoothly and non-overshoot adjusted, the cutting focal point is always kept at the optimal working distance, and the cutting edge quality and size accuracy are significantly improved, and the consistency and stability of the machining process are improved.

[0027] The control system of the application has advanced fault diagnosis and adaptive learning capabilities. When the displacement sensor measurement value is abnormal, the system can automatically attempt to recalibrate the zero point and full scale value; if the calibration fails, the system provides clear fault positioning information through the human-machine interface to guide the user to quickly eliminate hardware problems. For flame detection, the system can record the time and intensity of each abnormal event, and through pattern recognition of multiple consecutive abnormal data, it can analyze whether there is regular interference. Thus, the system can automatically and dynamically adjust the trigger threshold of the flame signal to achieve adaptive optimization of the detection strategy and effectively reduce the risk of false action caused by environmental changes. At the same time, the system records fault information and adjustment process, which provides a data basis for equipment maintenance, process optimization and subsequent intelligent upgrading, and improves the adaptability and long-term reliability of the system under different working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Figure 1 is a schematic diagram of the overall structure of the laser head control system of the application.

[0029] Figure 2 Figure 4 is a working principle block diagram of the photodetector.

[0030] Figure 3 Figure 6 is a dynamic adjustment flowchart of the height adjustment module.

[0031] 1 vertical servo drive motor; 2 laser reflection assembly; 3 displacement sensor; 4 laser head; 5 screw block mechanism; 6 belt drive mechanism; 7 photodetector. DETAILED DESCRIPTION

[0032] The content of the application will be further described in detail below in combination with the drawings.

[0033] The application provides a laser head control system with flame sensing, and the overall structure thereof is shown in Figure 1 The system includes a vertical servo drive motor 1, a laser reflection assembly 2, a displacement sensor 3, a laser head 4, a screw block mechanism 5, a belt drive mechanism 6, a photodetector 7, and a main controller (not shown in the figure). The specific embodiments of each component will be described in detail below in combination with the drawings.

[0034] The laser head 4 is the core executive component of the entire system, which is used to complete the cutting task of the workpiece. The photoelectric detector 7 is fixed on one side of the laser head 4 through threaded connection, and its installation position can ensure that the field of view angle of the photoelectric detector 7 can cover the working area of the laser head 4. So that the photoelectric detector 7 can monitor the flame signal generated in the processing process of the laser head 4 in real time. The displacement sensor 3 is installed on the other side of the laser head 4 through a support, and the ultrasonic wave emission end thereof faces the workpiece surface (i.e. the cutting position), which is used to measure the vertical distance between the laser head 4 and the workpiece surface. The displacement sensor 3 can remain stable when the laser head 4 moves, and accurately collect distance data.

[0035] The main controller communicates with the photoelectric detector 7 and the displacement sensor 3 through the CAN bus, ensuring the real-time and reliability of data transmission. The main controller is also connected with the vertical servo drive motor 1, which receives the instructions of the main controller and drives the screw slide mechanism 5 to adjust the height of the laser head 4. The screw slide mechanism 5 is responsible for realizing the displacement control of the laser head 4 in the vertical direction. So that the system can dynamically adjust the distance between the laser head 4 and the workpiece surface, while monitoring the change of the flame signal in real time.

[0036] The above describes the specific implementation of the present application in detail, including the connection relationship, position relationship and mutual cooperation relationship of each component, as well as the operation principle and process of the system. Through the above implementation, the present application can realize real-time monitoring of flame abnormalities and dynamic adjustment of the height of the laser head, thereby improving the safety and processing precision of the equipment.

[0037] In order to better enable relevant persons in the art to fully understand and implement the present application, the specific implementation principle of the present application is further described below in conjunction with a specific application scenario.

[0038] In the actual operation of the laser cutting equipment, the initialization operation of the system needs to be completed first. The operator sets the flame signal trigger threshold of the photoelectric detector 7 through the main controller, and calibrates the displacement sensor 3. When setting the flame signal trigger threshold, the photoelectric detector 7 will sample the ambient light intensity, calculate the average value of the background light noise, and set the trigger threshold of the flame signal based on this. Ensure that the photoelectric detector 7 can accurately identify the flame abnormal signal, and will not produce false alarm due to environmental light interference. When calibrating the displacement sensor 3, the laser head 4 is moved to the highest point of the workpiece surface, and the displacement sensor 3 reading at this time is recorded as the zero point; then the laser head 4 is moved to the maximum allowed height, and the displacement sensor 3 reading at this time is recorded as the full scale value. The main controller generates a linear mapping relationship according to the zero point and the full scale value, which is used for subsequent distance measurement. This calibration step provides an accurate data basis for subsequent height adjustment.

[0039] Subsequently, after starting the laser cutting operation, the photodetector 7 begins to monitor the flame signal in real time. The photodetector 7 collects the light intensity signal of the flame radiation and converts it into a voltage signal. The main controller filters the voltage signal and calculates its root mean square value after removing high-frequency interference. If the root mean square value exceeds the preset flame signal trigger threshold, it is determined that the flame is abnormal. At the same time, the displacement sensor 3 synchronously collects the vertical distance between the laser head 4 and the workpiece surface. The displacement sensor 3 calculates the actual distance between the laser head 4 and the workpiece surface by emitting ultrasonic pulses and receiving reflected signals. Through the cooperative work of the photodetector 7 and the displacement sensor 3, dual monitoring of the flame signal and cutting height is realized.

[0040] When the photodetector 7 detects that the flame signal intensity exceeds the preset threshold, the main controller immediately triggers an alarm and stops the laser output. The main controller sends a stop command to the laser cutting assembly, closes the laser output, and at the same time sends an alarm signal through the built-in buzzer of the photodetector 7, and displays the position and time information of the flame abnormality on the human-machine interface. In addition, the main controller records the current displacement sensor 3 reading and flame signal intensity for subsequent analysis of the fault cause. Through the fast response mechanism, safety hazards caused by flame abnormalities are effectively avoided.

[0041] During the cutting process, the main controller dynamically adjusts the height of the laser head 4 according to the measurement value of the displacement sensor 3. The main controller first reads the current measurement value of the displacement sensor 3 and compares it with the preset target vertical distance. If the measurement value is less than the target value, the main controller sends an upward command to the vertical servo drive motor 1 to control the screw block mechanism 5 to raise the laser head 4; if the measurement value is greater than the target value, the main controller sends a downward command to the vertical servo drive motor 1 to control the screw block mechanism 5 to lower the laser head 4. In order to reduce the oscillation phenomenon in the adjustment process, the main controller uses an incremental PID algorithm to calculate the adjustment amount. The formula is: ΔU = K P ×e + K I ×∑e + K D ×(e - e prev ),

[0042] Where ΔU is the adjustment amount, K P , K I , K D are the proportional, integral and differential coefficients respectively, e is the current error, e prev is the error at the last time. Further, the system can quickly and stably adjust the height of the laser head 4 to ensure cutting accuracy; through closed-loop control, accurate control of the distance between the laser head and the workpiece surface is realized.

[0043] If an abnormal situation occurs, the main controller records the fault information and performs corresponding recovery operations. For example, when the measurement value of the displacement sensor 3 exceeds the preset range, the main controller determines that the height adjustment is abnormal. At this time, the main controller first attempts to recalibrate the zero point and full-scale value of the displacement sensor 3. If the calibration fails, the main controller prompts the user through the human-machine interface to check the connection status of the displacement sensor 3 or replace the sensor. When the photoelectric detector 7 detects flame anomalies for multiple consecutive times, the main controller records the time interval and signal strength of each anomaly and analyzes whether there is a fixed pattern. If there is a pattern, the main controller automatically adjusts the trigger threshold of the flame signal to adapt to different processing environments, thereby improving the intelligence level of the system and being able to cope with complex and changing processing scenarios.

[0044] The working principle of the photodetector 7 is as follows Figure 2 As shown. After the photoelectric detector 7 collects the flame signal and converts it into a voltage signal, the main controller processes the voltage signal. The processing process includes filtering, RMS value calculation and comparison with the trigger threshold to ensure that the photoelectric detector 7 can accurately identify flame anomalies and send signals to the main controller in a timely manner. The dynamic adjustment process of the height adjustment module is shown in Figure 3 As shown in the figure, after the displacement sensor 3 measures the vertical distance between the laser head 4 and the workpiece surface, the main controller calculates the adjustment amount using an incremental PID algorithm and sends a command to the vertical servo drive motor 1. The vertical servo drive motor 1 drives the screw slider mechanism 5 to adjust the height of the laser head 4, thus achieving dynamic adjustment and ensuring that the distance between the laser head 4 and the workpiece surface always remains within the set range.

[0045] The above specific embodiments will allow those skilled in the art to easily implement the present invention. However, it should be understood that the present invention is not limited to the above specific embodiments. Based on the disclosed embodiments, those skilled in the art can arbitrarily combine different technical features to implement different technical solutions.

Claims

1. A flame-sensing laser cutting machine, characterized by: The invention comprises a laser cutting assembly, wherein the laser cutting assembly comprises a laser reflection assembly (2) and a laser head (4), wherein the laser head (4) is located directly below the laser reflection assembly (2), and further comprises a vertical servo drive motor (1), a belt transmission mechanism (6) and a screw slider mechanism (5), wherein the laser head (4) is arranged on the screw slider mechanism (5), and a displacement sensor (3) is arranged on the outside of the laser head (4) through a bracket, wherein the displacement sensor (3) is arranged obliquely, and the laser thereof coincides with the cutting position of the laser head (4).

2. The flame-sensing laser cutting machine according to claim 1, characterized in that: A photoelectric detector (7) is provided on one side of the laser head (4) close to the screw slider mechanism (5) for detecting flame anomalies during the processing.

3. The laser head control system of a flame-sensing laser cutting machine according to claim 2, characterized in that: The vertical servo drive motor (1) receives instructions from the main controller and controls a screw slider mechanism (5) to adjust the height of the laser head (1); the main controller (4) receives signals from a flame sensing module (2) and a displacement sensor (3) and processes them according to a preset logic.

4. The laser head control system of a flame-sensing laser cutting machine according to claim 3, characterized in that: The photoelectric detector (6) collects the light intensity signal of flame radiation and converts it into a voltage signal; the main controller performs filtering on the voltage signal, calculates its root mean square value, and compares the root mean square value with a preset flame signal trigger threshold.

5. The flame sensing laser head control system according to claim 3, characterized in that: The flame signal triggering threshold is 1.5 to 2 times the average value of background light noise, and the average value of background light noise is calculated by sampling the ambient light intensity through the photoelectric detector (6).

6. The flame sensing laser head control system according to claim 3, characterized in that: The displacement sensor (3) emits ultrasonic pulses and receives reflected signals, calculating the ultrasonic round trip time to obtain the actual distance between the laser head (1) and the workpiece surface; the main controller compares the measured value of the displacement sensor (3) with a preset target vertical distance, and uses an incremental PID algorithm to calculate an adjustment amount to control the screw slider mechanism (5) to adjust the height of the laser head (1).

7. The flame sensing laser head control system according to claim 6, characterized in that: The formula of the incremental PID algorithm is: ΔU=K P ×e+K I ×∑e+K D ×(ee prev ), Where ΔU is the adjustment amount, K P , K I , K D are proportional, integral and differential coefficients respectively, e is the current error, e prev is the error at the previous moment.

8. The flame sensing laser head control system according to claim 3, characterized in that: When the measured value of the displacement sensor (3) exceeds a preset range, the main controller determines that the height adjustment is abnormal and attempts to recalibrate the zero point and full-scale value of the displacement sensor (3); if the calibration fails, the main controller prompts the user through the human-machine interface to check the connection status of the displacement sensor (3) or replace the sensor.

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