LIBS liquid metal online composition analysis automatic detection control system and method

Abstract

The application belongs to the field of high-temperature liquid metal online component detection, in particular to a LIBS liquid metal online component analysis automatic detection control system and method, comprising: a main control cabinet, a LIBS module, a mechanical arm control module, a mechanical arm and a main control PLC; the main control cabinet comprises an industrial control touch screen, an industrial computer and a timing controller; the LIBS module is used for extending into the liquid metal to perform in-situ spectral excitation and spectral collection; the mechanical arm is used for carrying and driving the probe gun of the LIBS module to immerse in the liquid metal; the mechanical arm control module is internally provided with an end-side PLC, which is used for receiving the main control PLC instructions and driving the mechanical arm to perform actions; the main control PLC is in communication connection with the main control cabinet, the LIBS module and the end-side PLC respectively, and is used for processing sensor signals, performing state flow control and coordinating the linkage of each subsystem. The application realizes the full-automatic online detection of high-temperature liquid metal components, and has the advantages of high detection efficiency, good safety and strong stability.

Description

Technical Field

[0001] This invention belongs to the field of online component detection of high-temperature liquid metals, specifically a LIBS liquid metal online component analysis automatic detection and control system and method. Background Technology

[0002] Composition analysis of high-temperature liquid metals (such as molten steel, molten iron, molten aluminum, molten copper, etc.) is a crucial step in the metallurgical and casting industries, directly affecting the quality of the final product and production costs.

[0003] Currently, the main technologies are divided into: offline sampling analysis technology and online in-situ detection technology.

[0004] Offline sampling and analysis technology is highly accurate, mature, and reliable, but it suffers from significant latency, making it unsuitable for real-time control, highly dependent on manual intervention, and prone to information delays. Online in-situ detection technology is fast, offers strong real-time performance, and can achieve automated closed-loop control, but it also faces challenges in maintaining long-term stability and accuracy under extreme environments. In the trend of modern intelligent manufacturing, online in-situ detection is a clear development direction, particularly suitable for refining processes requiring rapid closed-loop control.

[0005] In online in-situ detection, laser-induced breakdown spectroscopy (LIBS) has become an indispensable core technology in this field due to its rapid and simultaneous multi-element analysis capabilities. Its principle involves using a focused high-power pulsed laser to excite the analyte into plasma, and then analyzing the plasma's emission spectrum to determine its chemical composition and content. LIBS technology offers advantages such as real-time processing, speed, remote non-contact detection, and a wide detection range, and has received widespread attention in recent years for online detection of high-temperature melt composition in the metallurgical industry.

[0006] Currently, LIBS technology in the field of online liquid metal detection mainly revolves around two major technical routes: non-contact and immersion methods. In large smelting plants, due to the open environment, non-contact methods are more susceptible to various on-site interferences, resulting in unstable optical signals and inconsistent detection results. The core of immersion technology lies in directly inserting a protective probe into the liquid metal. Through high-temperature resistant probe design and inert gas protection and purification, a localized, protected measurement zone is created in the extreme environment. Because plasma is directly excited within the melt, the signal intensity is usually stronger, which is beneficial for measuring many key elements with characteristic spectral lines in the ultraviolet band that are difficult to measure accurately using non-contact methods.

[0007] However, immersion online inspection still faces many technical challenges in practical applications. First, the melt temperature is typically above 1000℃ (up to 1800℃), and the intense heat radiation makes it difficult for operators to closely inspect and control the equipment, necessitating a fully automated inspection process. Second, existing immersion inspection devices mostly rely on manual or semi-automatic control, resulting in low inspection efficiency, poor repeatability, and difficulty in ensuring consistency of measurement conditions across tests. Furthermore, the probe is easily damaged during inspection due to surface crusting or viscosity differences in the melt, and there is a lack of effective anomaly monitoring and safety protection mechanisms. In addition, existing systems have shortcomings in sensor fusion, multi-level safety control, and maintaining stable internal environments under extreme conditions, hindering the industrial-scale application of immersion LIBS online inspection technology.

[0008] Therefore, it is necessary to implement a fully automated detection control process in this type of detection scheme. This fully automated control scheme can effectively shorten the detection time, improve detection efficiency, and thus enhance the real-time response capability of online in-situ detection. Summary of the Invention

[0009] The purpose of this invention is to provide an automatic detection and control system and method for online composition analysis of liquid metals (LIBS). This system, with a main control PLC as its core, integrates information from multiple sensors and achieves fully automated operation of the detection process through a distributed control architecture. It also features a three-level independent safety control mechanism. This aims to solve the problems of low automation, insufficient safety, and poor detection stability in existing immersion LIBS detection solutions. Furthermore, this method improves detection efficiency and real-time performance while ensuring personnel and production safety, and further enhances the system's detection stability through multi-level sensor control.

[0010] The technical solution adopted by the present invention to achieve the above objectives is: an automatic detection and control system for online composition analysis of liquid metals using LIBS, comprising: a main control cabinet, a LIBS module, a robotic arm control module, a robotic arm, and a main control PLC;

[0011] The main control cabinet includes: an industrial control touch screen, an industrial computer, and a timing controller;

[0012] The industrial control touch screen is used to display the readings of each sensor in real time, provide an operation interface, and display the detection process status and result parameters.

[0013] The industrial control computer is used to control the timing controller to generate timing signals and analyze spectral data to calculate the composition and content of liquid metal;

[0014] The timing controller is used to generate synchronous timing control signals to precisely coordinate the timing of laser output from the LIBS module and the timing of spectrometer acquisition in the LIBS module.

[0015] The LIBS module is used to extend into the liquid metal to perform in-situ spectral excitation and spectral acquisition on the high-temperature liquid metal in a localized controlled measurement area, and to transmit the acquired spectral signals to the main control cabinet for analysis.

[0016] The robotic arm is used to carry and drive the probe of the LIBS module to be immersed in liquid metal, and its rated load capacity is not less than 500 kg.

[0017] The robotic arm control module is located in a safe area away from high temperature and high magnetic field environments. It has an end-side PLC that receives instructions from the main control PLC and drives the robotic arm to perform actions. The robotic arm control module receives three independent control signals from the main control PLC, the handheld operating terminal, and the cabinet panel.

[0018] The main control PLC is connected to the main control cabinet, the LIBS module and the end-side PLC. It is used to centrally process the sensor signals collected by the sensor group in the LIBS module, execute state process control and coordinate the linkage of each subsystem. The main control PLC and the end-side PLC interact using the S7 communication protocol. The main control PLC maintains the internal temperature of the LIBS module within a set range by adjusting the cooling circulation of the fan and liquid cooling pipe.

[0019] The sensor signals include temperature signals, pressure signals, flow signals, humidity signals, and displacement signals.

[0020] The LIBS module includes: a laser, a spectrometer, a probe, a sensor group, a control valve group, a probe housing, an optical chamber, liquid cooling pipes, and wiring harnesses;

[0021] The probe is a component made of high-temperature resistant ceramic material, and its front end forms a local measurement area. The probe extends forward along the axial center line of the probe housing and extends out of the front end of the probe housing.

[0022] The sensor array is used to monitor the internal environment and pipeline status of the module;

[0023] The control valve assembly is used to regulate the on / off state and flow rate of each air passage;

[0024] The optical chamber is located in the middle section inside the probe housing. The optical chamber and the probe gun are optically coupled together via an optical path channel. An optical window is provided inside the optical chamber.

[0025] The laser and the spectrometer are respectively located on opposite sides of the optical chamber and connected to the optical path of the optical chamber. The laser emitted by the laser reaches the front end of the probe through the optical window inside the optical chamber, and the spectrometer collects the plasma emission spectrum through the same optical path.

[0026] The liquid cooling pipe is arranged in a circular or meandering manner inside the probe housing at the mounting base of the laser and spectrometer. The two ends of the liquid cooling pipe are respectively connected to the inlet and outlet of the external cooling circulation system to circulate heat dissipation for the laser and spectrometer.

[0027] The wiring harness runs along the inner wall of the probe housing, and the control lines and signal lines of the sensors and control valve groups located inside the probe housing are gathered and led out to the outside of the probe housing, and connected to the main control PLC and the corresponding control module respectively.

[0028] The sensor group includes: a temperature sensor group, a pressure sensor group, a flow sensor, and a distance sensor;

[0029] The temperature sensor group includes: a temperature sensor disposed inside the probe housing near the optical chamber area and a probe temperature sensor attached to the root of the probe or near the inner wall of the front end of the probe housing.

[0030] Temperature sensor used to monitor the temperature at key locations inside the probe housing;

[0031] The probe temperature sensor is used to monitor the temperature of the probe body to assist in the determination of probe breakage anomalies;

[0032] The pressure sensor group includes: a compressed air supply pressure sensor, an argon gas inlet pressure sensor, a probe internal pressure sensor disposed in the gas path channel inside the probe, a spectrometer flushing gas pressure sensor, and a pipeline pressure sensor; wherein, the compressed air supply pressure sensor is disposed on the compressed air supply pipeline, the argon gas inlet pressure sensor is disposed on the argon gas inlet pipeline, the probe internal pressure sensor is disposed in the gas path channel inside the probe, the spectrometer flushing gas pressure sensor is disposed on the spectrometer flushing gas path, and the pipeline pressure sensor is disposed at the pipeline pressure detection point;

[0033] The flow sensor is an argon flow meter installed inside the probe housing on the argon gas supply pipeline and located in the middle section of the gas path between the argon gas control valve and the probe.

[0034] The ranging sensor is located inside the probe housing and faces the moving part of the probe gun, and is used to monitor the downward displacement of the probe gun;

[0035] The probe housing is also equipped with a humidity sensor for monitoring the humidity of the internal environment. The humidity sensor and the temperature sensor are located adjacent to each other in the area near the optical chamber.

[0036] The control valve assembly includes: an exhaust valve, an argon control valve, and a compressed air control valve;

[0037] The exhaust valve is located at the exhaust port, the argon control valve is located on the argon supply pipeline, and the compressed air control valve is located on the compressed air supply pipeline.

[0038] The sensor information received and processed by the main control PLC includes: the probe internal temperature measured by the temperature sensor, the probe internal humidity measured by the humidity sensor, the probe internal temperature measured by the probe temperature sensor, the compressed air pressure measured by the compressed air supply pressure sensor, the argon inlet pressure measured by the argon inlet pressure sensor, the instantaneous argon flow rate measured by the argon flow meter, the exhaust valve opening, the spectrometer internal gas pressure measured by the spectrometer flushing gas pressure sensor, the probe internal pressure measured by the probe internal pressure sensor, and the probe descent distance measured by the distance measuring sensor.

[0039] A control method for an automated detection and control system for online composition analysis of LIBS liquid metals includes the following steps:

[0040] Step 1) Set automatic detection parameters and perform self-check on the key sensor parameters of the detection system. If any abnormality is found, lock the system and prevent it from entering the automatic detection process.

[0041] The automatic detection parameters include: initial flow rate, descent time, descent pressure, delayed detection time, flow rate during detection, motor rise time, measurement timeout, upper limit of probe temperature, upper limit of pressure, lower limit of pressure, and minimum flow rate.

[0042] Step 2) The end-side PLC receives the automatic detection command and triggers the automatic detection process;

[0043] Step 3) The main control PLC enters the start-up delay state and performs parameter initialization operations; the main control PLC adjusts the cooling circulation of the fan and liquid cooling pipes and combines it with compressed air purging, and works with the temperature and humidity sensors set inside the probe housing to maintain the temperature and humidity inside the probe housing within the set range; the main control PLC starts full-process abnormal state monitoring.

[0044] The parameter initialization operation includes: closing the pressure exhaust valve, setting the initial flow rate value, and delaying the blowing control;

[0045] Step 4) The system enters the probe descent state, and the main control PLC automatically sets the descent flow rate value and controls the probe to descend;

[0046] Step 5) After the probe is in place, the system enters the detection and measurement state. The main control PLC automatically sets the detection flow rate value, adjusts the opening of the exhaust valve, and opens the argon control valve and compressed air control valve. The main control PLC sends instructions to the host computer, and the timing controller generates a synchronous timing signal to coordinate the laser light output and the spectrometer acquisition, starting LIBS spectral detection. The main control PLC monitors whether the total detection time exceeds the limit. If it does, a measurement timeout abnormality is triggered. During the detection and measurement state, the temperature sensor and humidity sensor monitor the temperature and humidity changes inside the probe housing in real time. If the temperature and humidity exceed the set range, a high temperature abnormality or a humidity abnormality is triggered.

[0047] Step 6) After the test is completed, the system enters the end rising state, and the main control PLC controls the probe to rise to the initial position; after the probe rises to the position, the main control PLC resets all status flags and parameters and returns to the standby state.

[0048] In step 1), the key sensing parameters include: pipeline gas pressure, argon flow rate measured by argon flow meter, internal temperature of probe housing, spectrometer cleaning status, and laser switch status.

[0049] If any parameter is abnormal or does not meet the startup conditions, the system will be locked.

[0050] The automatic detection command is issued by the one-button detection button on the industrial wireless handheld control box that is connected to the end-side PLC; the full-process abnormal state monitoring is started synchronously in the start-up delay state and continues throughout all four states: start-up delay state, probe descent state, detection and measurement state, and end-up state.

[0051] During the entire automatic detection process from steps 3) to 6), the main control PLC performs real-time diagnosis based on multi-sensor data. The multi-sensor data includes data collected by the probe temperature sensor, argon flow meter, pressure sensor group, temperature sensor, humidity sensor, and distance sensor. At the same time, it performs timing consistency verification in conjunction with the set execution time of each process. When the sensor data exceeds the limit or the process execution time exceeds the limit, the main control PLC automatically interrupts the detection process, closes the argon control valve and compressed air control valve, and drives the robotic arm to reset the probe to a safe position through the robotic arm control module. This safety mechanism is the first level of safety mechanism.

[0052] During the automatic detection process, the system also includes a second-level security mechanism and a third-level security mechanism, independent of the first-level security mechanism, to form a three-level independent security control mechanism:

[0053] The second level of safety mechanism is: the on-site operator intervenes in the emergency stop through a handheld operating terminal. The handheld operating terminal is an industrial wireless handheld control box. Its receiver is connected to the end-side PLC. After the operator triggers the emergency stop, the end-side PLC directly sends a reset command to the robotic arm, triggering the robotic arm to automatically reset. This level of safety mechanism does not go through the main control PLC.

[0054] The third level of safety mechanism is as follows: when both the main control PLC and the handheld terminal fail, a manual reset can be performed through the independent emergency control circuit on the cabinet panel. This emergency control circuit is a pure hardware circuit, independent of the main control PLC and the end-side PLC, and directly controls the drive unit of the robotic arm to achieve emergency safe recovery of the robotic arm.

[0055] Step 4) specifically involves:

[0056] When the probe is inserted into the liquid metal, if the pressure measured by the pressure sensor inside the probe instantly exceeds the preset threshold and the temperature measured by the probe temperature sensor rises sharply, it is determined that the probe has entered the melt. If the pressure measured by the pressure sensor inside the probe drops sharply under stable air pressure, it is determined to be a probe breakage abnormality, and the system automatically terminates the detection process and performs a reset. If the descent time exceeds the preset descent time, it is determined to be a descent timeout abnormality.

[0057] During the detection and measurement process, the temperature and humidity changes inside the probe are monitored in real time by temperature and humidity sensors. If the temperature or humidity exceeds the set range, a high temperature abnormality or humidity abnormality is triggered. If the total duration of spectral detection exceeds the set measurement timeout time, a measurement timeout abnormality is triggered.

[0058] During the lifting process, the system monitors the lifting time. If the time exceeds the set motor lifting time, it is determined to be an lifting timeout abnormality.

[0059] The present invention has the following beneficial effects and advantages:

[0060] 1. This invention achieves fully automated online detection of the composition of high-temperature liquid metals. The invention employs a PLC-based LIBS fully automated detection system. The main control PLC integrates information from multiple sensors and controls the end-side PLC to drive a robotic arm to move at a preset angle and trajectory, stably and accurately inserting the LIBS probe into a designated position below the liquid metal surface for spectral acquisition. The system effectively suppresses probe vibration within the melt by real-time adjustment of gas flow rate and exhaust valve opening, ensuring the stability of the detection process. Simultaneously, the insertion depth is dynamically judged and controlled based on the liquid metal pressure to ensure consistent measurement conditions and improve the repeatability and reliability of the detection data.

[0061] 2. This invention features a three-level independent safety control mechanism to ensure system operational safety. During automatic detection, the system receives three independent control signals from the main control PLC, handheld operating terminal, and cabinet panel, forming multiple safety safeguards: First, the main control PLC performs real-time anomaly diagnosis based on multi-sensor data and the execution time of each process; once an anomaly is detected, the process is immediately interrupted and a safety operation is performed. Second, on-site operators can intervene in an emergency stop at any time based on the equipment's operating status via the handheld operating terminal, triggering the robotic arm's automatic reset. Third, in extreme cases where both the main control PLC and the handheld terminal fail, the robotic arm can be manually reset via an independent emergency control circuit on the cabinet panel, achieving emergency safe retrieval.

[0062] 3. This invention boasts high detection efficiency and can be seamlessly integrated into existing production processes. For the analysis of components in high-temperature liquid metals (typically around 1000℃), traditional manual sampling and testing methods are time-consuming, cannot be performed online, and struggle to support intelligent continuous production. This invention, using a robotic arm to automatically drive the detection probe, completes a single online component detection in less than 2 minutes. This significantly shortens the analysis cycle and minimally impacts the normal operation of the smelting process, providing an effective technical means for real-time component monitoring and closed-loop quality control in the smelting process. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0064] Figure 2 This is a schematic diagram of the control flow of the present invention;

[0065] Figure 3 This is a schematic diagram of the safety control mechanism of the present invention;

[0066] Figure 4 This is a schematic diagram of the exception handling mechanism of the present invention;

[0067] Figure 5 This is a schematic diagram of the overall structure of the probe of the present invention;

[0068] Figure 6 This is a schematic diagram of the overall structure of the automatic monitoring system of the present invention;

[0069] Figure 7 This is a schematic diagram of the automatic monitoring system of the present invention.

[0070] Among them, 1 is the probe, 2 is the probe temperature sensor, 3 is the probe housing, 4 is the argon flow meter, 5 is the pressure sensor group, 6 is the control valve group, 7 is the optical chamber, 8 is the wire harness, 9 is the laser, 10 is the spectrometer, 11 is the liquid cooling pipe, 12 is the temperature sensor, 13 is the humidity sensor, 14 is the distance sensor, and 15 is the liquid metal. Detailed Implementation

[0071] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0072] like Figure 1 and Figure 6 As shown, the present invention provides an automatic detection and control system for online composition analysis of liquid metals via LIBS, which mainly includes a main control cabinet, a LIBS module, a robotic arm control module, a robotic arm, and a main control PLC.

[0073] The main control cabinet includes an industrial control touchscreen, an industrial computer, and a timing controller. The industrial control touchscreen displays real-time sensor readings, provides a host computer software interface, and displays the detection process status, detection result parameters, and related graphical information. The industrial computer controls the timing controller to generate timing signals and analyzes the data collected by the spectrometer based on a self-developed algorithm model to calculate the composition and content of the liquid metal. The timing controller generates synchronous timing control signals to precisely coordinate the timing of laser emission and plasma signal acquisition by the spectrometer.

[0074] The LIBS module includes: a laser 9, a spectrometer 10, a probe 1, a sensor group, a control valve group 6, a probe housing 3, an optical chamber 7, a liquid cooling pipe 11, and a wiring harness 8. The laser 9 emits high-energy laser pulses towards the liquid metal to be detected, exciting plasma to be generated on its surface. The spectrometer 10 collects and analyzes the emission spectrum of the plasma. The probe 1 is a component made of high-temperature resistant ceramic material, with its front end forming a local measurement area. The probe 1 extends forward along the axial centerline of the probe housing 3 and protrudes beyond the front end of the probe housing 3.

[0075] An optical chamber 7 is located in the middle section inside the probe housing 3. The optical chamber 7 is optically coupled to the probe 1 via an optical path channel, and an optical window is provided inside the optical chamber 7. The laser 9 and the spectrometer 10 are respectively located on opposite sides of the optical chamber 7 and are optically connected to the optical chamber 7. The laser emitted by the laser 9 reaches the front end of the probe 1 through the optical window in the optical chamber 7 to excite the liquid metal 15 to generate plasma. The spectrometer 10 collects the plasma emission spectrum through the same optical path.

[0076] The liquid cooling pipe 11 is arranged in a circular or meandering manner inside the probe housing 3 at the mounting base of the laser 9 and the spectrometer 10. The two ends of the liquid cooling pipe 11 are respectively connected to the inlet and outlet of the external cooling circulation system to circulate heat dissipation for the laser 9 and the spectrometer 10.

[0077] The wiring harness 8 runs along the inner wall of the probe housing 3, and the signal lines of the sensor and control valve group 6 located inside the probe housing 3 are brought together and led out to the outside of the probe housing 3, and connected to the main control PLC and the corresponding control module respectively.

[0078] The robotic arm is used to carry and drive the probe 1 of the LIBS module into the liquid metal 15. Its rated load capacity is not less than 500 kg, ensuring reliable operation in high-temperature environments.

[0079] The robotic arm control module is located in a safe area away from high-temperature and high-magnetic environments. It contains an end-side PLC that receives commands from the main control PLC and drives the robotic arm to perform actions. The robotic arm control module receives three independent control signals from the main control PLC, the handheld operating terminal, and the cabinet panel. The end-side PLC can execute various preset motion logics, responsible for controlling the robotic arm's rotation, lifting, and other movements.

[0080] The main control PLC, as the core controller of the system, communicates with the main control cabinet, the LIBS module, and the end-side PLCs. It is used to centrally process sensor signals, execute state flow control, and coordinate the linkage of various subsystems. The main control PLC and the end-side PLCs interact using the S7 communication protocol. The main control PLC maintains the internal temperature of the LIBS module within a set range by adjusting the cooling circulation of the fan and liquid cooling pipe 11.

[0081] like Figure 5 As shown, the overall structure of the probe includes the following components:

[0082] The probe 1 is a high-temperature resistant component that is directly immersed in liquid metal 15. It is made of high-temperature resistant ceramic material, and its front end forms a local measurement area. The probe temperature sensor 2 is attached to the base of the probe 1 or to the inner wall near the front end of the probe housing 3, and is used to monitor the temperature of the probe 1 body in real time.

[0083] The probe housing 3 constitutes the main external structure of the probe, providing support and protection. The optical chamber 7 is located in the middle section inside the probe housing 3, containing an optical window, and is the core area for laser excitation and spectral acquisition.

[0084] Argon flow meter 4 is installed on the argon supply pipeline inside the probe housing 3, located in the middle section of the gas path between the argon control valve and the probe 1, and is used to detect and provide feedback on the real-time flow rate of the argon gas used for purging.

[0085] Pressure sensor group 5 includes a compressed air supply pressure sensor, an argon gas inlet pressure sensor, a probe internal pressure sensor, a spectrometer flushing gas pressure sensor, and a pipeline gas pressure sensor. Each sensor is installed at a corresponding gas supply pipeline or gas path detection point.

[0086] The control valve group 6 includes an exhaust valve, an argon control valve, and a compressed air control valve, which are respectively located at the exhaust port, the argon supply line, and the compressed air supply line, and are used to regulate the on / off state and flow rate of each gas line.

[0087] The wiring harness 8 integrates power supply and signal lines. It runs along the inner wall of the probe housing 3, and gathers the signal lines of the sensors and control valve group 6 located in various places inside the probe housing 3 before leading them out to the outside of the probe housing 3, and connecting them to the main control PLC and the corresponding control module respectively.

[0088] Laser 9 emits high-energy laser pulses to break down the surface of liquid metal and generate plasma. Spectrometer 10 collects and analyzes the plasma emission spectrum to determine its composition. Liquid cooling pipe 11, a component of the cooling circulation system, is arranged in a circular or meandering manner inside the probe housing 3 at the mounting base of laser 9 and spectrometer 10 to dissipate heat from high-heat components such as laser 9 and spectrometer 10.

[0089] Temperature sensor 12 is located inside probe housing 3 near optical chamber 7 to monitor the temperature at key locations inside the probe. Humidity sensor 13 is located inside probe housing 3 near optical chamber 7, adjacent to temperature sensor 12, to monitor the humidity of the internal environment of the probe. Distance sensor 14 is located inside probe housing 3 and faces the moving part of probe 1 to monitor the descent displacement of probe 1.

[0090] like Figure 5 As shown, the sensor group includes: a temperature sensor group, a pressure sensor group, a flow sensor, and a distance sensor.

[0091] The temperature sensor group includes a temperature sensor 12 located inside the probe housing 3 near the optical chamber 7, and a probe temperature sensor 2 attached to the base of the probe 1 or near the inner wall of the front end of the probe housing 3. Temperature sensor 12 monitors the temperature at key locations inside the probe housing 3. Probe temperature sensor 2 monitors the temperature of the probe 1 body to assist in determining probe breakage abnormalities.

[0092] The pressure sensor group includes a compressed air supply pressure sensor, an argon gas inlet pressure sensor, an internal pressure sensor 5 located in the gas path of the probe 1, a spectrometer flushing gas pressure sensor, and a pipeline pressure sensor. The compressed air supply pressure sensor is located on the compressed air supply pipeline and is used to detect the supply pressure of compressed air. The argon gas inlet pressure sensor is located on the argon gas inlet pipeline and is used to detect the inlet pressure of argon gas. The internal pressure sensor 5 is located in the gas path inside the probe 1 and is primarily used to determine the insertion depth of the probe 1 and diagnose probe breakage. The spectrometer flushing gas pressure sensor is located on the spectrometer flushing gas path and is used to detect the gas pressure inside the spectrometer 10. The pipeline pressure sensor is located at the pipeline pressure detection point and is used to monitor the gas pressure status within the pipeline.

[0093] The flow sensor is an argon flow meter 4, which is installed inside the probe housing 3 on the argon gas supply line and located in the middle of the gas path between the argon control valve and the probe 1. It is used to detect the real-time flow rate of the argon gas used for purging.

[0094] The ranging sensor 14 is located inside the probe housing 3 and faces the moving part of the probe 1, and is used to monitor the downward displacement of the probe 1.

[0095] The probe housing 3 is also equipped with a humidity sensor 13 for monitoring the humidity of the internal environment. The humidity sensor 13 is located adjacent to the temperature sensor 12 in the area near the optical chamber 7.

[0096] Control valve assembly 6 includes: an exhaust valve, an argon control valve, and a compressed air control valve. The exhaust valve is located at the exhaust port, the argon control valve is located on the argon supply line, and the compressed air control valve is located on the compressed air supply line. Control valve assembly 6 is used to adjust the gas flow rate and switch the gas supply path according to the needs of the detection process.

[0097] The sensor information collected by the main control PLC includes: the probe internal temperature measured by temperature sensor 12, the probe internal humidity measured by humidity sensor 13, the probe internal temperature measured by probe temperature sensor 2, the compressed air pressure measured by compressed air supply pressure sensor, the argon inlet pressure measured by argon inlet pressure sensor, the instantaneous argon flow rate measured by argon flow meter 4, the exhaust valve opening, the gas pressure inside the spectrometer 10 measured by spectrometer flushing gas pressure sensor, the probe internal pressure measured by probe internal pressure sensor 5, and the probe descent distance measured by distance sensor 14.

[0098] like Figure 2 As shown, the present invention provides an automatic detection and control method for online composition analysis of LIBS liquid metals, comprising the following steps:

[0099] Step 1: System self-test and parameter preset

[0100] On-site operators first set the operating parameters for each step in the main control PLC via the industrial control touchscreen. The set automatic detection parameters include the initial flow rate, descent time, descent pressure, delay detection time, flow rate during detection, motor rise time, measurement timeout, upper limit probe temperature, upper limit pressure, lower limit pressure, and minimum flow rate.

[0101] After the parameters are set, a self-check is performed on the key sensing parameters of the detection system. These key sensing parameters include pipeline gas pressure, argon flow rate measured by argon flow meter 4, internal temperature of probe housing 3, cleaning status of spectrometer 10, and on / off status of laser 9. If any parameter is abnormal or does not meet the automatic detection start-up conditions, the system is locked, preventing entry into the automatic detection process.

[0102] Step 2: Process Trigger

[0103] After confirming that the on-site environment meets the conditions for automatic detection, the on-site operator issues an automatic detection command via the one-button detection button on the industrial wireless handheld control box. The receiver of the industrial wireless handheld control box is connected to the end-side PLC. After receiving the automatic detection command, the end-side PLC triggers the automatic detection process and controls the robotic arm to perform the corresponding actions.

[0104] Step 3: Start Delay

[0105] The main control PLC enters the start-up delay state. In this state, parameter initialization operations are performed, including closing the pressure exhaust valve, setting the initial flow rate value, and executing delayed air blowing control. Simultaneously, the full-process abnormal state monitoring function is activated. Full-process abnormal state monitoring is activated synchronously in the start-up delay state and continues throughout all four states: start-up delay state, probe descent state, detection and measurement state, and end-of-life rise state.

[0106] The startup delay state also includes control steps for the internal environment of the LIBS module. The main control PLC adjusts the cooling circulation of the fan and liquid cooling pipe 11, combined with compressed air purging, and works with the temperature sensor 12 and humidity sensor 13 located inside the probe housing 3 to maintain the temperature and humidity inside the probe housing 3 within a set range. The liquid cooling pipe 11 is arranged in a circular or meandering manner inside the probe housing 3 at the mounting base of the laser 9 and spectrometer 10 to circulate heat dissipation for the laser 9 and spectrometer 10. Compressed air is regulated by the compressed air control valve 6 and introduced into the probe housing 3 to purge the optical window in the optical chamber 7 and maintain a positive pressure environment inside the probe to prevent dust and splashes from the high-temperature liquid metal 15 from contaminating the optical components.

[0107] Through the above-mentioned coordinated control, the laser 9 and the spectrometer 10 are ensured to operate under optimal temperature conditions, and the cleanliness of the optical window is maintained to ensure the signal-to-noise ratio of spectral acquisition.

[0108] Step 4: Lower the probe

[0109] The system transitions from a startup delay state to probe descent. The main control PLC automatically sets the descent flow rate and controls the probe 1 to descend. During probe 1's descent, the internal pressure sensor 5 monitors the internal pressure of probe 1 in real time, and the probe temperature sensor 2 monitors the temperature of probe 1 in real time. Based on the detection data from the internal pressure sensor 5 and the probe temperature sensor 2, the main control PLC determines whether probe 1 has inserted the liquid metal 15 and whether a probe breakage abnormality has occurred.

[0110] When the pressure measured by the internal pressure sensor 5 of the probe instantly exceeds the preset threshold and the temperature measured by the probe temperature sensor 2 rises sharply, it is determined that probe 1 has entered the melt. If the pressure measured by the internal pressure sensor 5 of the probe suddenly drops when the inlet pressure is stable, it is determined to be a probe breakage abnormality, and the system automatically terminates the detection process and performs a reset. The main control PLC also determines whether probe 1 has descended to the correct position (i.e., whether the internal pressure of probe 1 has reached the preset descent pressure value) based on the detection value of the internal pressure sensor 5, and whether a descent timeout abnormality has occurred based on whether the descent time exceeds the preset descent time.

[0111] Step 5: Detection and Measurement

[0112] Once probe 1 is in position, the system enters the detection and measurement state. The main control PLC automatically sets the detection flow rate value, dynamically adjusts the opening of the exhaust valve to stabilize the probe 1's posture and suppress vibration, and opens the argon control valve and compressed air control valve.

[0113] The main control PLC sends instructions to the host computer, and the timing controller generates a synchronization timing signal to coordinate the light output from laser 9 and the acquisition by spectrometer 10, thus initiating LIBS spectral detection. The main control PLC monitors whether the total detection time exceeds the measurement timeout period; if it does, it triggers a measurement timeout exception.

[0114] During the detection and measurement process, the temperature sensor 12 and humidity sensor 13 monitor the temperature and humidity changes inside the probe housing 3 in real time. If the temperature or humidity exceeds the set range, a high temperature abnormality or a humidity abnormality is triggered.

[0115] Step 6: End the ascent

[0116] After the test is completed, the system enters the final ascent state. The main control PLC sets the ascent flow rate, closes the exhaust valve, and controls probe 1 to rise to the initial position within the set motor ascent time. The main control PLC monitors the ascent process duration; if it exceeds the set motor ascent time, it is determined to be an ascent timeout abnormality.

[0117] Step 7: Reset standby

[0118] After probe 1 rises to its position, the main control PLC automatically resets all status flags and parameters, returns to standby mode, and waits for the next automatic detection command.

[0119] The entire process of a single online component detection takes no more than 2 minutes.

[0120] The aforementioned automatic detection method includes a safety control mechanism, specifically:

[0121] like Figure 3 As shown, the present invention has a three-level independent safety control mechanism in the automatic detection process.

[0122] The first level of safety mechanism involves real-time diagnostics performed by the main control PLC based on multi-sensor data. This multi-sensor data includes data collected by the probe temperature sensor 2, argon flow meter 4, pressure sensor group 5, temperature sensor 12, humidity sensor 13, and distance sensor 14. It also incorporates the set execution times for each process for timing consistency verification. When sensor data exceeds limits or a process execution timeout is detected, the main control PLC automatically interrupts the detection process, closes the argon control valve and compressed air control valve 6, and drives the robotic arm control module to reset the probe 1 to a safe position.

[0123] The second-level safety mechanism involves emergency stop intervention by on-site operators via a handheld control terminal. The handheld terminal is an industrial wireless handheld control box, whose receiver communicates with the end-side PLC. After the operator presses the emergency stop button, the end-side PLC directly sends a reset command to the robotic arm, triggering automatic reset. This level of safety mechanism operates independently of the first-level safety mechanism, without going through the main control PLC.

[0124] The third level of safety mechanism: In the extreme case where both the main control PLC and the handheld terminal fail, a manual reset can be performed via an independent emergency control circuit on the cabinet panel. This emergency control circuit is a purely hardware circuit, independent of the main control PLC and the end-side PLC, and directly controls the hydraulic or electric drive unit of the robotic arm to achieve emergency safe retrieval of the robotic arm.

[0125] like Figure 4 As shown, the present invention involves the following anomaly detection and handling schemes during the automatic detection process:

[0126] (a) Sensor status monitoring before startup

[0127] During the system self-test phase, the status of various sensors is monitored to confirm whether the automatic detection start conditions are met. Monitored items include the argon flow rate measured by argon flow meter 4, the compressed air supply pressure measured by compressed air supply pressure sensor, the probe internal pressure measured by probe internal pressure sensor 5, the probe internal temperature and humidity measured by temperature sensor 12 and humidity sensor 13, the probe pressure measured by probe temperature sensor 2, the spectrometer flushing gas pressure measured by spectrometer flushing gas pressure sensor, and the robotic arm position. If any monitored item is abnormal, the system is locked and automatic detection is prohibited.

[0128] (II) Monitoring of Gun Breakage Anomalies

[0129] After the probe enters the descent state, the probe breakage anomaly monitoring is initiated, and this monitoring continues throughout the entire automatic detection process. When probe 1 is inserted into the liquid metal 15, if the pressure measured by the internal pressure sensor 5 of the probe instantly exceeds the preset threshold and the temperature measured by the probe temperature sensor 2 rises sharply, it is determined that probe 1 has entered the melt. If, under stable inlet pressure, the pressure measured by the internal pressure sensor 5 of the probe suddenly drops, it is determined to be a probe breakage anomaly, and the system automatically terminates the detection process and performs a reset.

[0130] (III) Monitoring of abnormal descent timeout

[0131] If the descent time exceeds the preset descent time during the probe's descent phase, it is determined to be a descent timeout abnormality, and the system automatically terminates the detection process and performs a reset.

[0132] (iv) Monitoring of abnormal temperature and humidity inside the probe

[0133] During the detection and measurement process, the temperature and humidity changes inside the probe are monitored in real time by temperature sensor 12 and humidity sensor 13. If the temperature or humidity exceeds the set range, a high temperature abnormality or humidity abnormality is triggered.

[0134] (v) Monitoring of measurement timeout anomalies

[0135] If the total duration of spectral detection exceeds the set measurement timeout during the detection and measurement process, a measurement timeout exception will be triggered.

[0136] (vi) Monitoring of abnormal rise timeout

[0137] During the lifting process, the system monitors the lifting time. If the time exceeds the set motor lifting time, it is determined to be an lifting timeout abnormality.

[0138] Example:

[0139] like Figure 7 As shown below, the specific implementation method of the present invention will be further explained using a PLC-based fully automated liquid metal detection scheme as an example.

[0140] Taking molten steel testing as an example, the temperature of molten steel is typically around 1000℃~1600℃. On-site operators first set the operating parameters for each step in the main control PLC, including the initial flow rate, descent time, descent pressure, delay detection time, flow rate during detection, motor rise time, measurement timeout, upper limit probe temperature, upper limit pressure, lower limit pressure, and minimum flow rate. After confirming that the on-site environment meets the automatic detection conditions, the process is started via the "one-click detection" button on the industrial wireless handheld control box.

[0141] After the process starts, the main control PLC executes status control sequentially:

[0142] During the startup delay state, the main control PLC closes the pressure exhaust valve, sets the initial flow rate, executes delayed air blowing control, and simultaneously initiates full-process abnormal state monitoring. The main control PLC, through adjusting the fan and water cooling system, in conjunction with sensors and controllers, maintains the internal temperature of the LIBS module within the set range, ensuring that the laser and spectrometer operate under optimal temperature conditions.

[0143] During probe descent, the main control PLC automatically sets the descent flow rate to control the probe's descent. After the probe enters the molten metal, if the pressure measured by the internal pressure sensor momentarily exceeds the preset threshold, and the temperature measured by the temperature sensor rises sharply, it is determined that the probe has entered the molten metal. The main control PLC monitors the internal pressure changes of the probe in real time. If the probe pressure suddenly drops while the inlet pressure is stable, it is considered a probe breakage abnormality, and the system automatically terminates the detection process and performs a reset. If the descent time exceeds the preset descent completion time, it is considered a descent timeout abnormality.

[0144] During the detection and measurement process, after the probe descends to the set pressure position, the main control PLC sets the detection flow rate value, dynamically adjusts the exhaust valve opening to suppress probe vibration, opens the corresponding argon and compressed air valves, and sends a command to the host computer to start LIBS spectral detection. The timing controller precisely coordinates the timing of laser light emission and spectrometer plasma signal acquisition. The main control PLC simultaneously monitors the total spectral detection time; if it exceeds the set measurement timeout, it is judged as a measurement timeout anomaly. During the detection process, temperature and humidity sensors monitor the internal temperature and humidity changes of the probe in real time; if they exceed the set range, a high temperature anomaly or a humidity anomaly is triggered.

[0145] After the ascent phase ends and the test is completed, the main control PLC sets the ascent flow rate, closes the exhaust valve, and controls the probe to rise to the initial position within the set motor ascent time. The main control PLC monitors the ascent process duration; if it exceeds the set motor ascent time, it is considered an ascent timeout abnormality.

[0146] After the probe rises to its position, the system automatically resets all detection status flags and parameters, returns to standby mode, and waits for the next automatic detection command.

[0147] During operation, the main control PLC collects information from multiple sensors in real time, including probe internal temperature and humidity, probe gun internal temperature, compressed air pressure, argon inlet pressure, argon instantaneous flow rate, exhaust valve opening, spectrometer internal gas pressure, probe gun internal pressure, and probe descent distance. It also monitors for anomalies based on the allowable execution time for each state. The process is interrupted immediately upon detection of an anomaly, ensuring the safety and stability of each test.

[0148] This invention uses a robotic arm to automatically drive the detection probe, and the entire process of a single online component detection takes no more than 2 minutes. It can be seamlessly integrated into existing production processes, providing an effective technical means for real-time component monitoring and closed-loop quality control in the smelting process.

[0149] Those skilled in the art will understand that the above description is merely a preferred embodiment of the present invention, and the features described in the various embodiments of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. This is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An automatic detection and control system for online composition analysis of LIBS liquid metals, characterized in that, include: Main control cabinet, LIBS module, robotic arm control module, robotic arm and main control PLC; The main control cabinet includes: an industrial control touch screen, an industrial computer, and a timing controller; The industrial control touch screen is used to display the readings of each sensor in real time, provide an operation interface, and display the detection process status and result parameters. The industrial control computer is used to control the timing controller to generate timing signals and analyze spectral data to calculate the composition and content of liquid metal; The timing controller is used to generate a synchronous timing control signal to precisely coordinate the timing of the laser (9) output from the LIBS module and the acquisition by the spectrometer (10) of the LIBS module; The LIBS module is used to extend into the liquid metal to perform in-situ spectral excitation and spectral acquisition on the high-temperature liquid metal in a localized controlled measurement area, and to transmit the acquired spectral signals to the main control cabinet for analysis. The robotic arm is used to carry and drive the probe (1) of the LIBS module to be immersed in liquid metal (15), and its rated load capacity is not less than 500 kg; The robotic arm control module is located in a safe area away from high temperature and high magnetic field environments. It has an end-side PLC that receives instructions from the main control PLC and drives the robotic arm to perform actions. The robotic arm control module receives three independent control signals from the main control PLC, the handheld operating terminal, and the cabinet panel. The main control PLC is connected to the main control cabinet, the LIBS module and the end-side PLC respectively. It is used to centrally process the sensor signals collected from the sensor group in the LIBS module, execute state process control and coordinate the linkage of each subsystem. The main control PLC and the end-side PLC use the S7 communication protocol to interact. The main control PLC maintains the internal temperature of the LIBS module within the set range by adjusting the cooling cycle of the fan and liquid cooling pipe (11). The sensor signals include temperature signals, pressure signals, flow signals, humidity signals, and displacement signals.

2. The LIBS liquid metal online composition analysis automatic detection and control system according to claim 1, characterized in that, The LIBS module includes: a laser (9), a spectrometer (10), a probe (1), a sensor group, a control valve group (6), a probe housing (3), an optical chamber (7), a liquid cooling pipe (11), and a wiring harness (8). The probe (1) is a component made of high-temperature resistant ceramic material, and its front end forms a local measurement area. The probe (1) extends forward along the axial center line of the probe housing (3) and extends out of the front end of the probe housing (3). The sensor array is used to monitor the internal environment and pipeline status of the module; The control valve group (6) is used to regulate the on / off state and flow rate of each air passage; The optical chamber (7) is located in the middle section inside the probe housing (3). The optical chamber (7) and the probe gun (1) are optically coupled together through an optical path channel. An optical window is provided inside the optical chamber (7). The laser (9) and the spectrometer (10) are respectively set on opposite sides of the optical chamber (7) and connected to the optical path of the optical chamber (7). The laser emitted by the laser (9) reaches the front end of the probe (1) through the optical window in the optical chamber (7), and the spectrometer (10) collects the plasma emission spectrum through the same optical path. The liquid cooling pipe (11) is arranged in a circular or meandering manner inside the probe housing (3) at the mounting base of the laser (9) and the spectrometer (10). The two ends of the liquid cooling pipe (11) are respectively connected to the inlet and outlet of the external cooling circulation system to circulate heat dissipation for the laser (9) and the spectrometer (10). The wiring harness (8) runs along the inner wall of the probe housing (3), and the control lines and signal lines of the sensor and control valve group (6) located inside the probe housing (3) are brought together and led out to the outside of the probe housing (3) to be connected to the main control PLC and the corresponding control module respectively.

3. The LIBS liquid metal online composition analysis automatic detection and control system according to claim 2, characterized in that, The sensor group includes: a temperature sensor group, a pressure sensor group, a flow sensor, and a distance sensor; The temperature sensor group includes: a temperature sensor (12) disposed inside the probe housing (3) near the optical chamber (7) and a probe temperature sensor (2) attached to the root of the probe (1) or near the inner wall of the front end of the probe housing (3). Temperature sensor (12) is used to monitor the temperature at key locations inside the probe housing (3); The probe temperature sensor (2) is used to monitor the temperature of the probe (1) body to assist in the determination of probe breakage abnormality; The pressure sensor group includes: a compressed air supply pressure sensor, an argon gas inlet pressure sensor, a probe internal pressure sensor (5) installed in the gas path channel inside the probe (1), a spectrometer flushing gas pressure sensor, and a pipeline gas pressure sensor (5); wherein, the compressed air supply pressure sensor is installed on the compressed air supply pipeline, the argon gas inlet pressure sensor is installed on the argon gas inlet pipeline, the probe internal pressure sensor (5) is installed in the gas path channel inside the probe (1), the spectrometer flushing gas pressure sensor is installed on the spectrometer flushing gas path, and the pipeline gas pressure sensor (5) is installed at the pipeline gas pressure detection point; The flow sensor is an argon flow meter (4) installed inside the probe housing (3) on the argon gas supply pipeline and located in the middle section of the gas path between the argon control valve and the probe (1). The ranging sensor (14) is located inside the probe housing (3) and faces the moving part of the probe (1) to monitor the downward displacement of the probe (1); The probe housing (3) is also equipped with a humidity sensor (13) for monitoring the humidity of the internal environment. The humidity sensor (13) and the temperature sensor (12) are arranged adjacent to each other in the area near the optical chamber (7).

4. The LIBS liquid metal online composition analysis automatic detection and control system according to claim 2, characterized in that, The control valve group (6) includes: an exhaust valve, an argon control valve, and a compressed air control valve; The exhaust valve is located at the exhaust port, the argon control valve is located on the argon supply pipeline, and the compressed air control valve is located on the compressed air supply pipeline.

5. The LIBS liquid metal online composition analysis automatic detection and control system according to claim 1, characterized in that, The sensor information collected by the main control PLC includes: the probe internal temperature measured by temperature sensor (12), the probe internal humidity measured by humidity sensor (13), the probe internal temperature measured by probe temperature sensor (2), the compressed air pressure measured by compressed air supply pressure sensor, the argon inlet pressure measured by argon inlet pressure sensor, the instantaneous argon flow rate measured by argon flow meter (4), the exhaust valve opening, the gas pressure inside the spectrometer (10) measured by spectrometer flushing gas pressure sensor, the probe internal pressure measured by probe internal pressure sensor (5), and the probe descent distance measured by distance measuring sensor (14).

6. The control method for an automatic detection and control system for online composition analysis of LIBS liquid metals according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1) Set automatic detection parameters and perform self-check on the key sensor parameters of the detection system. If any abnormality is found, lock the system and prevent it from entering the automatic detection process. The automatic detection parameters include: initial flow rate, descent time, descent pressure, delayed detection time, flow rate during detection, motor rise time, measurement timeout, upper limit of probe temperature, upper limit of pressure, lower limit of pressure, and minimum flow rate. Step 2) The end-side PLC receives the automatic detection command and triggers the automatic detection process; Step 3) The main control PLC enters the start-up delay state and performs parameter initialization operation; the main control PLC adjusts the cooling cycle of the fan and liquid cooling pipe (11) and combines it with compressed air purging, and with the temperature sensor (12) and humidity sensor (13) set inside the probe housing (3), maintains the temperature and humidity inside the probe housing (3) within the set range; the main control PLC starts full-process abnormal state monitoring; The parameter initialization operation includes: closing the pressure exhaust valve, setting the initial flow rate value, and delaying the blowing control; Step 4) The system enters the probe descent state, and the main control PLC automatically sets the descent flow rate value and controls the probe (1) to descend; Step 5) After the probe (1) is in place, the system enters the detection and measurement state. The main control PLC automatically sets the detection flow rate value, adjusts the opening of the exhaust valve, opens the argon control valve and the compressed air control valve, and sends instructions to the host computer. The timing controller generates a synchronous timing signal to coordinate the light output of the laser (9) and the acquisition of the spectrometer (10) to start LIBS spectral detection. The main control PLC monitors whether the total detection time exceeds the limit. If it exceeds the limit, a measurement timeout abnormality is triggered. In the detection and measurement state, the temperature sensor (12) and the humidity sensor (13) monitor the temperature and humidity changes inside the probe housing (3) in real time. If the temperature and humidity exceed the set range, a high temperature abnormality or a humidity abnormality is triggered. Step 6) After the detection is completed, the system enters the end rising state, and the main control PLC controls the probe (1) to rise to the initial position; after the probe (1) rises to the position, the main control PLC resets all status flags and parameters and returns to the standby state.

7. The control method for an automatic detection and control system for online composition analysis of LIBS liquid metals according to claim 6, characterized in that, In step 1), the key sensing parameters include: pipeline pressure, argon flow rate measured by argon flow meter (4), internal temperature of probe housing (3), cleaning status of spectrometer (10), and switching status of laser (9). If any parameter is abnormal or does not meet the startup conditions, the system will be locked. The automatic detection command is issued by the one-button detection button on the industrial wireless handheld control box that is connected to the end-side PLC; the full-process abnormal state monitoring is started synchronously in the start-up delay state and continues throughout all four states: start-up delay state, probe descent state, detection and measurement state, and end-up state.

8. The control method for an automatic detection and control system for online composition analysis of LIBS liquid metals according to claim 6, characterized in that, During the entire automatic detection process from step 3) to step 6), the main control PLC performs real-time diagnosis based on multi-sensor data. The multi-sensor data includes data collected by the probe temperature sensor (2), argon flow meter (4), pressure sensor group (5), temperature sensor (12), humidity sensor (13), and distance sensor (14). At the same time, it performs timing consistency verification in conjunction with the set execution time of each process. When the sensor data exceeds the limit or the process execution time is exceeded, the main control PLC automatically interrupts the detection process, closes the argon control valve and compressed air control valve (6), and drives the robotic arm through the robotic arm control module to reset the probe (1) to a safe position. This safety mechanism is the first level safety mechanism.

9. The control method for an automatic detection and control system for online composition analysis of LIBS liquid metals according to claim 8, characterized in that, During the automatic detection process, the system also includes a second-level security mechanism and a third-level security mechanism, independent of the first-level security mechanism, to form a three-level independent security control mechanism: The second level of safety mechanism is: the on-site operator intervenes in the emergency stop through a handheld operating terminal. The handheld operating terminal is an industrial wireless handheld control box. Its receiver is connected to the end-side PLC. After the operator triggers the emergency stop, the end-side PLC directly sends a reset command to the robotic arm, triggering the robotic arm to automatically reset. This level of safety mechanism does not go through the main control PLC. The third level of safety mechanism is as follows: when both the main control PLC and the handheld terminal fail, a manual reset can be performed through the independent emergency control circuit on the cabinet panel. This emergency control circuit is a pure hardware circuit, independent of the main control PLC and the end-side PLC, and directly controls the drive unit of the robotic arm to achieve emergency safe recovery of the robotic arm.

10. The control method for an automatic detection and control system for online composition analysis of LIBS liquid metals according to claim 6, characterized in that, Step 4) specifically involves: When the probe (1) is inserted into the liquid metal (15), if the pressure measured by the internal pressure sensor (5) of the probe instantly exceeds the preset threshold and the temperature measured by the probe temperature sensor (2) rises sharply, it is determined that the probe (1) has entered the melt. If the pressure measured by the internal pressure sensor (5) of the probe drops sharply under the condition of stable air pressure, it is determined that the probe is broken. The system automatically terminates the detection process and performs a reset. If the descent time exceeds the preset descent time, it is determined that the descent timeout is abnormal. During the detection and measurement state, the temperature and humidity changes inside the probe are monitored in real time by temperature sensor (12) and humidity sensor (13). If the temperature and humidity exceed the set range, a high temperature abnormality or humidity abnormality is triggered. If the total duration of spectral detection exceeds the set measurement timeout time, a measurement timeout abnormality is triggered. During the lifting process, the system monitors the lifting time. If the time exceeds the set motor lifting time, it is determined to be an lifting timeout abnormality.

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