Automatic calibration method and system for mining laser gas detector

Abstract

The invention discloses an automatic calibration method and system for a mining laser gas detector, and relates to the technical field of instrument calibration. The method comprises the following steps: dividing detection beam parameters into measurement beam parameters and reference beam parameters; enabling the measurement light beam parameter to penetrate through the to-be-measured gas area to obtain a measurement signal, and enabling the reference light beam parameter to penetrate through the reference gas chamber to obtain a reference signal; performing photoelectric conversion calculation on the reference signal to obtain a gas concentration detection value; the gas concentration detection value is compared and analyzed with a reference data value according to the central wavelength position of the mining laser gas detector, and a calibration unit is activated according to a comparison result; and automatically correcting the mining laser gas detector, generating a correction parameter set, calculating a measurement signal, and generating a concentration value of the gas to be detected. The technical problems of low calibration efficiency and unstable calibration precision of the mining laser gas detector in the prior art are solved, and the technical effects of realizing automatic calibration of the mining laser gas detector and improving the calibration efficiency and precision are achieved.

Description

Technical Field

[0001] This invention relates to the field of instrument calibration technology, specifically to an automatic calibration method and system for a mining laser gas detector. Background Technology

[0002] Mining laser gas detectors are key equipment in coal mine safety monitoring systems, primarily used for real-time detection of harmful gas concentrations such as methane and carbon monoxide in the mine environment to prevent gas explosions and poisoning accidents. Existing mining laser gas detectors typically employ a detection principle based on tunable semiconductor laser absorption spectroscopy, calculating gas concentration by analyzing the absorption characteristics of the signal after the beam passes through the gas being measured. However, during long-term operation, factors such as temperature, humidity, light source aging, optical path contamination, and changes in detector sensitivity can cause drift or errors in the detection results, necessitating periodic calibration to ensure measurement accuracy. Current calibration methods mostly rely on manual operation or comparison with external standard gases, which are cumbersome, inefficient, and prone to instability due to human factors, failing to meet the requirements of continuous monitoring and high reliability in mines. Summary of the Invention

[0003] This application provides an automatic calibration method and system for a mining laser gas detector, which solves the technical problems of low calibration efficiency and unstable calibration accuracy of existing mining laser gas detectors.

[0004] The first aspect of this application provides an automatic calibration method for a mining laser gas detector, the method comprising: The mining laser gas detector is activated to generate detection beam parameters, which are then divided into measurement beam parameters and reference beam parameters. The measurement beam parameters are passed through the area of ​​the gas to be measured to obtain a measurement signal, and the reference beam parameters are passed through a reference gas chamber to obtain a reference signal, which includes reference data values. Based on the measurement signal, the reference signal is photoelectrically converted and calculated to obtain a gas concentration detection value. The gas concentration detection value is compared and analyzed with the reference data value according to the center wavelength position of the mining laser gas detector, and the calibration unit is activated based on the comparison result. The calibration unit automatically calibrates the mining laser gas detector, generates a calibration parameter set, calculates the measurement signal, and generates the gas concentration value to be measured.

[0005] A second aspect of this application provides an automatic calibration system for a mining laser gas detector, the system comprising: Parameter Generation Component: Activates the mining laser gas detector to generate detection beam parameters, dividing the detection beam parameters into measurement beam parameters and reference beam parameters; Signal Acquisition Component: Allows the measurement beam parameters to pass through the area of ​​the gas to be measured to acquire a measurement signal, and allows the reference beam parameters to pass through a reference gas chamber to acquire a reference signal, the reference signal containing reference data values; Calculation Component: Performs photoelectric conversion calculation on the reference signal based on the measurement signal to obtain the gas concentration detection value; Comparison and Analysis Component: Compares and analyzes the gas concentration detection value with the reference data value according to the center wavelength position of the mining laser gas detector, and activates the calibration unit based on the comparison result; Correction Component: Automatically corrects the mining laser gas detector through the calibration unit, generates a correction parameter set to calculate the measurement signal, and generates the gas concentration value to be measured.

[0006] One or more technical solutions provided in this application have at least the following technical effects or advantages: First, the mining laser gas detector is activated to generate detection beam parameters, which are then divided into measurement beam parameters and reference beam parameters. Next, the measurement beam parameters are passed through the area of ​​the gas to be measured to acquire a measurement signal, while the reference beam parameters are passed through a reference gas chamber to acquire a reference signal containing reference data values. Further, based on the measurement signal, photoelectric conversion calculations are performed on the reference signal to obtain the gas concentration detection value. Then, the gas concentration detection value is compared and analyzed with the reference data value according to the center wavelength position of the mining laser gas detector, and the calibration unit is activated based on the comparison result. Finally, the calibration unit automatically calibrates the mining laser gas detector, generating a calibration parameter set to calculate the measurement signal and generate the gas concentration value to be measured. This solves the technical problems of low calibration efficiency and unstable calibration accuracy in existing mining laser gas detectors, achieving the technical effect of automatic calibration of mining laser gas detectors and improving calibration efficiency and accuracy. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 A schematic diagram of the automatic calibration method for a mining laser gas detector provided in this application embodiment; Figure 2 This is a schematic diagram of the automatic calibration system for a mining laser gas detector provided in an embodiment of this application.

[0009] Explanation of reference numerals in the attached figures: Parameter generation component 11, signal acquisition component 12, calculation component 13, comparison and analysis component 14, and calibration component 15. Detailed Implementation

[0010] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0011] Example 1, as Figure 1 As shown, this application provides an automatic calibration method for a mining laser gas detector, wherein the method includes: The mining laser gas detector is activated to generate detection beam parameters, which are then divided into measurement beam parameters and reference beam parameters.

[0012] In this embodiment, the microcontroller sends a start command to the internal control module of the laser gas detector, activating the laser drive circuit and putting the mine laser gas detector into operation. The microcontroller outputs a superimposed waveform of bias current signal and modulation current signal through a digital-to-analog converter. The bias current is used to maintain the ground-state emission power of the laser, and the modulation current is used to periodically modulate the laser wavelength within a set frequency range. Under the action of the drive current, the mine laser gas detector emits an infrared detection beam, which carries specific wavelength and power parameters, constituting the detection beam parameters. The infrared detection beam is collimated by a collimating lens to ensure uniform energy distribution, and then introduced into a beam-splitting optical unit to perform energy splitting processing on the detection beam. The beam-splitting optical unit splits the detection beam into two independently propagating beams according to a preset energy distribution ratio: one beam serves as the measurement beam parameter, used to pass through the gas region to obtain absorption characteristics; the other beam serves as the reference beam parameter, used to pass through the internal reference gas chamber to obtain a stable reference signal.

[0013] Furthermore, activating a mining laser gas detector to generate detection beam parameters, and dividing the detection beam parameters into measurement beam parameters and reference beam parameters, includes the following methods: A bias current signal is generated by sending instructions to a digital-to-analog converter via a microcontroller; the bias current signal drives the mining laser gas detector to generate infrared detection beam parameters; the infrared detection beam parameters are coupled to a beam splitting optical unit, and the beam splitting optical unit divides the infrared detection beam parameters into two independently propagating beam parameters according to a preset energy ratio to obtain the measurement beam parameters and the reference beam parameters.

[0014] The microcontroller sends a start command to the digital-to-analog converter, which then outputs a corresponding bias current signal. This bias current signal is used to maintain the laser's stable emission within the set operating current range, ensuring that the output optical power is within the linear response range.

[0015] Based on a bias current signal, the laser driving module drives the semiconductor laser in the mining laser gas detector to emit an infrared detection beam. This infrared detection beam includes wavelength parameters, frequency modulation parameters, and output power parameters, constituting the infrared detection beam parameters. Subsequently, the infrared detection beam undergoes energy shaping and optical axis calibration via an optical fiber or collimating lens to ensure uniform beam energy distribution and meet the incident light spot requirements. The shaped infrared detection beam is coupled to a beam-splitting optical unit, which can be a semi-transparent beam splitter, a polarizing beam splitter, or a fiber optic beam splitter, used to distribute the energy of the input beam. The beam-splitting optical unit divides the infrared detection beam into two independently propagating beam parameters according to a preset energy ratio, such as 7:3 or 5:5. One beam serves as the measurement beam parameter, used to pass through the gas region to perform absorption detection; the other beam serves as the reference beam parameter, used to pass through the internal reference gas chamber to provide a standardized reference signal.

[0016] The measurement beam parameters are passed through the region of the gas to be measured to obtain a measurement signal, and the reference beam parameters are passed through the reference gas chamber to obtain a reference signal, which includes reference data values.

[0017] Based on tunable laser absorption spectroscopy, a measurement beam output from a laser passes through the region of the gas to be tested in a mine. The gas molecules selectively absorb the light signal within a specific wavelength range, thus forming corresponding absorption characteristics in the spectrum. The beam transmitted through the gas region becomes the emitted measurement beam, whose energy and wavelength characteristics change. This emitted measurement beam is received by a photodetector located at the end of the optical path of the detector, which converts the optical signal into a corresponding electrical signal for output. This electrical signal is the measurement signal, used to reflect the intensity of the absorption characteristics of the gas to be tested.

[0018] Simultaneously, the reference beam parameters pass through a separate reference gas chamber along a separate path. This chamber contains a standard gas of known concentration, such as methane or carbon monoxide, to provide a stable and traceable reference absorption spectrum. After transmission through the reference gas chamber, the reference beam is received by a reference photodetector and converted into a second electrical signal, forming a reference signal. This reference signal contains reference data values ​​used to characterize the standard absorption features at the known concentration.

[0019] Furthermore, the method of obtaining a measurement signal by passing the measurement beam parameters through the region of the gas to be measured and obtaining a reference signal by passing the reference beam parameters through a reference gas cell includes: The measurement beam parameters are guided through the gas region to obtain the gas parameters; the gas parameters absorb the measurement beam parameters to generate an outgoing measurement beam parameter; the outgoing measurement beam parameter is received by a measurement photodetector and converted to generate a first electrical signal, which is the measurement signal; the reference beam parameters are guided through a reference gas chamber to generate an outgoing reference beam parameter; the outgoing reference beam parameter is received by a reference photodetector and converted to generate a second electrical signal, which is the reference signal.

[0020] The measurement beam parameters are guided along the detection channel through the target gas region in the mine. The detection channel is a sealed or semi-open structure, filled with mine air samples. During its passage, the measurement beam selectively absorbs the target gas molecules based on the principle of tunable laser absorption spectroscopy. Different gas components absorb different wavelengths of laser light with varying intensities, thus forming characteristic absorption curves in the spectral signal. After transmission through the target gas region, the beam energy and wavelength distribution change, forming the output measurement beam parameters. These parameters are received by a measurement photodetector located at the end of the optical path. The photodetector converts the received optical signal into an electrical signal, generating a first electrical signal. This first electrical signal simultaneously contains environmental interference factors (such as light source fluctuations and dust scattering) and gas absorption information; this signal is the measurement signal, used to characterize the absorption features of the target gas.

[0021] Simultaneously, the reference beam parameters are guided through an internally located reference gas chamber, which is an independent, sealed optical cavity filled with a standard gas of known concentration (e.g., methane or carbon monoxide standard gas) to provide a stable and traceable absorption reference. As the reference beam passes through the reference gas chamber, its spectrum is modulated by the standard gas according to a fixed absorption coefficient, forming the emitted reference beam parameters. These parameters are received by a reference photodetector and converted into a second electrical signal, which is the reference signal. This second electrical signal contains information about laser fluctuations, source energy drift, and standard absorption characteristics.

[0022] Based on the measured signal, the reference signal is converted into a photoelectric value to obtain the gas concentration detection value.

[0023] Furthermore, the method for obtaining a gas concentration detection value by performing photoelectric conversion calculation on the reference signal based on the measured signal includes: The first and second electrical signals are respectively input into a low-noise transimpedance amplifier for conversion and amplification to obtain a first voltage signal and a second voltage signal. Based on the first and second voltage signals, a high-speed analog-to-digital conversion is performed to obtain a digital measurement signal and a digital reference signal. The digital reference signal is amplified by lock-in to extract the second harmonic component. The mine laser gas detector is locked in real time according to the second harmonic component to determine the center wavelength parameter of the mine laser gas detector. Harmonic analysis is performed on the digital measurement signal according to the center wavelength parameter to extract the first and second harmonic components of the digital measurement signal. The amplitude of the first and second harmonic components of the digital measurement signal is analyzed to obtain the amplitude ratio. The gas concentration detection value is then calculated.

[0024] First, the first electrical signal output from the measurement photodetector and the second electrical signal output from the reference photodetector are respectively input into a low-noise transimpedance amplifier for current-to-voltage conversion and signal amplification. The transimpedance amplifier converts the weak photocurrent signal into a voltage signal with stable amplitude, and reduces thermal noise and drift error by optimizing the matching of the feedback resistor and the input impedance to obtain the first voltage signal and the second voltage signal. Subsequently, based on the first voltage signal and the second voltage signal, a high-speed analog-to-digital converter is used for synchronous sampling to convert the analog signal into a digital signal sequence, obtaining the digital measurement signal and the digital reference signal respectively. The digital signal is a digital sequence that can be calculated in real time by a digital signal processor for subsequent lock-in amplification and harmonic analysis processing. Next, the digital reference signal is subjected to lock-in amplification to extract its second harmonic component. Specifically, the system sets the lock-in amplification reference frequency based on the laser's modulation frequency, performs synchronous detection and digital low-pass filtering on the digital reference signal to filter out the fundamental frequency and high-frequency noise, retaining only the second harmonic signal corresponding to twice the modulation frequency. The second harmonic component reflects the wavelength shift at the center of the laser absorption curve. Based on this component, the system adjusts the laser drive current and temperature control module in real time to keep the mine laser gas detector at the center of the target absorption spectrum, thus determining the center wavelength parameter of the mine laser gas detector. After obtaining the center wavelength parameter, harmonic analysis is performed on the digital measurement signal according to the center wavelength parameter to extract the first and second harmonic components of the digital measurement signal. The first harmonic component reflects the linear response intensity of gas absorption, and the second harmonic component reflects the change in the shape of the absorption curve. Together, they characterize the absorption characteristics of the gas to be measured by the optical signal. Finally, the amplitude of the first harmonic component and the second harmonic component of the digital measurement signal are analyzed to calculate their amplitude ratio. The amplitude ratio is proportional to the gas absorption intensity. The amplitude ratio is calculated by linear or nonlinear interpolation using a pre-established standard gas concentration-amplitude ratio calibration curve to obtain the gas concentration detection value.

[0025] Furthermore, the method for extracting the second harmonic component of the digital reference signal by performing lock-in amplification includes: The modulation frequency of the mining laser gas detector is retrieved, and the modulation frequency is mapped to the digital domain for same-frequency analysis to extract the sine reference signal and cosine reference signal. The digital reference signal is multiplied by the sine reference signal to obtain a first product signal. The digital reference signal is multiplied by the cosine reference signal to obtain a second product signal. The first product signal and the second product signal are digitally low-pass filtered to obtain the real part data and imaginary part data of the second harmonic. The second harmonic component of the digital reference signal is calculated based on the real part data and the imaginary part data of the second harmonic.

[0026] The modulation frequency of the mining laser gas detector is invoked. This modulation frequency is a periodic modulation component in the laser drive current, used for wavelength scanning near the gas absorption spectral lines. This modulation frequency is mapped to the time-domain sequence of the digital signal processing unit, enabling same-frequency analysis in the digital domain. The digital signal processor generates two sets of mutually orthogonal reference signals based on this modulation frequency: a sine reference signal and a cosine reference signal, used for synchronous demodulation. Subsequently, the digital reference signals are multiplied by the sine and cosine reference signals respectively, resulting in two same-frequency product signals. The first product signal reflects the correlation between the reference signal and the sine phase component, and the second product signal reflects the correlation between the reference signal and the cosine phase component. Next, digital low-pass filtering is performed on the first and second product signals respectively to filter out the fundamental frequency and high-frequency noise components of the modulation frequency, retaining only the DC component corresponding to twice the modulation frequency, thereby obtaining the real and imaginary parts of the second harmonic wave, respectively. The cutoff frequency of the low-pass filter is typically set to one-hundredth to one-thousandth of the modulation frequency to ensure smooth and stable second harmonic components. Finally, based on the real and imaginary part data of the second harmonic, the amplitude and phase information of the harmonic components are determined using the square root of the sum of squares or arctangent calculation methods to obtain the second harmonic components of the digital reference signal. These second harmonic components can accurately reflect the degree of offset of the laser wavelength relative to the center of the gas absorption spectral line.

[0027] Furthermore, the amplitude ratio of the first harmonic component and the second harmonic component of the digital measurement signal is obtained through amplitude analysis to calculate the gas concentration detection value. The method includes: The amplitude ratio is obtained by dividing the second harmonic amplitude of the digital measurement signal by the first harmonic amplitude of the digital measurement signal; a concentration-amplitude ratio calibration curve is constructed based on a standard gas with a known concentration; the amplitude ratio is linearly interpolated on the concentration-amplitude ratio calibration curve, and the gas concentration detection value is determined based on the interpolation result.

[0028] Specifically, the extracted first harmonic amplitude is compared with the second harmonic amplitude, i.e., the second harmonic amplitude of the digital measurement signal is divided by the first harmonic amplitude of the digital measurement signal to obtain the amplitude ratio. This amplitude ratio reflects the nonlinear response characteristics of the gas absorption curve. The detection system is calibrated using standard gas samples of known concentrations. The amplitude ratios of multiple standard gases with different concentrations are collected under the same modulation frequency, wavelength range, and detection conditions to construct a concentration-amplitude ratio calibration curve. The calibration curve can be obtained by polynomial fitting or piecewise linear fitting, representing the functional relationship between the amplitude ratio and the gas concentration under standard conditions. By substituting the amplitude ratio into the concentration-amplitude ratio calibration curve for interpolation calculation or inverse function fitting, the corresponding gas concentration detection value is obtained.

[0029] The gas concentration detection value is compared and analyzed with the reference data value according to the center wavelength position of the mining laser gas detector, and the calibration unit is activated based on the comparison result.

[0030] Furthermore, the gas concentration detection value is compared and analyzed with the reference data value according to the center wavelength position of the mining laser gas detector, and the calibration unit is activated based on the comparison result. The method includes: The system continuously monitors the second harmonic peak position of the digital reference signal and determines the center wavelength position of the mining laser gas detector based on the second harmonic peak position of the digital reference signal. It then performs a first comparison between the detected gas concentration value and a standard concentration reference value to calculate the concentration deviation. Next, it performs a second comparison between the center wavelength position of the mining laser gas detector and a calibrated wavelength reference value to calculate the wavelength drift. The system then compares the concentration deviation value with a first preset threshold and the wavelength drift with a second preset threshold. When the concentration deviation value continuously exceeds the first preset threshold and / or the wavelength drift continuously exceeds the second preset threshold, it extracts a first duration of continuous exceedance and a second duration of continuous exceedance. When both the first duration of continuous exceedance and the second duration of continuous exceedance reach a preset stable duration, it generates a calibration activation command. The calibration activation command is sent to the calibration unit, triggering the calibration unit to enter a standby state to prepare for the execution of an automatic calibration program.

[0031] The system continuously monitors the second harmonic peak position of the digital reference signal, using this position to reflect the center drift of the laser absorption curve. Since the laser wavelength is susceptible to slight drift due to temperature, driving current, and optical cavity stress, the system determines the current center wavelength position of the mining laser gas detector by real-time tracking of the second harmonic peak, ensuring dynamic stability in the wavelength locking process. The system performs a first comparison analysis between the detected gas concentration value and a standard concentration reference value, calculating the concentration deviation. The standard concentration reference value is derived from a known concentration of standard gas in the reference chamber, and the concentration deviation reflects the degree of deviation of the detected value from the standard value. Simultaneously, the system performs a second comparison between the current center wavelength position and a preset calibration wavelength reference value, calculating the wavelength drift to assess the degree of deviation of the laser wavelength from the center of the ideal absorption spectrum.

[0032] The system compares the concentration deviation value with a first preset threshold and the wavelength drift with a second preset threshold. The first preset threshold defines the permissible error range for gas concentration detection, typically expressed as a percentage of the standard concentration; the second preset threshold defines the acceptable range for wavelength drift, typically measured in nanometers or picometers. When the concentration deviation value consistently exceeds the first preset threshold and / or the wavelength drift consistently exceeds the second preset threshold, the system considers the detector's state to have deviated.

[0033] To avoid false triggering caused by transient interference, the system further extracts the first continuous exceedance duration and the second continuous exceedance duration. When both reach the preset stable duration (e.g., the continuous exceedance of the threshold time reaches 30 seconds or several sampling cycles), the system generates a calibration activation command. The calibration activation command is sent to the calibration unit through the communication bus, triggering the calibration unit to enter the standby state and prepare to execute the automatic calibration program.

[0034] Furthermore, before determining the concentration deviation value against a first preset threshold and the wavelength shift against a second preset threshold, the method includes: The first preset threshold is a relative threshold used to determine whether the concentration measurement accuracy is out of tolerance; the second preset threshold is an absolute threshold used to determine whether the wavelength of the mining laser gas detector has drifted; if the absolute value of the concentration deviation is greater than the first preset threshold, or the absolute value of the wavelength drift is greater than the second preset threshold, it is determined to be a preliminary abnormality.

[0035] The first preset threshold is a relative threshold used to determine whether the concentration measurement accuracy is out of tolerance. This threshold is determined based on the calibration concentration of the standard gas and the system's measurement accuracy level, and is usually taken as ±1% to ±3% of the standard concentration. When the deviation between the actual measured gas concentration value and the standard concentration reference value exceeds this relative threshold, it indicates that the accuracy of the system measurement results has decreased.

[0036] The second preset threshold is an absolute threshold used to determine whether the center wavelength of the mining laser gas detector has drifted. This threshold is determined by a spectral calibration experiment and is used to limit the allowable offset range of the laser output wavelength relative to the center of the absorption spectral line. When the actual center wavelength position deviates from the calibrated wavelength reference value by more than this absolute threshold, it indicates that the laser wavelength stability has decreased or the temperature control module has experienced a slight misalignment.

[0037] During real-time detection, the system compares the calculated concentration deviation and wavelength drift with the first and second preset thresholds, respectively. When the absolute value of the concentration deviation exceeds the first preset threshold, or the absolute value of the wavelength drift exceeds the second preset threshold, the system determines the current detection state as a preliminary abnormal state. This preliminary abnormal state will serve as a trigger condition to initiate subsequent continuous monitoring and stabilization duration determination processes to determine whether an automatic calibration process needs to be initiated.

[0038] The calibration unit automatically calibrates the mine laser gas detector, generates a set of calibration parameters, calculates the measurement signal, and generates the concentration value of the gas to be measured.

[0039] The calibration unit comprises two parts: a laser drive current correction module and a temperature control compensation module, used to correct the output power and wavelength stability of the light source, respectively. Specifically, the laser drive current correction module automatically adjusts the laser drive current amplitude and modulation depth parameters based on the difference between the concentration deviation and the wavelength drift, so that the output wavelength is re-aligned with the center region of the gas absorption spectrum; the temperature control compensation module performs minute temperature corrections on the laser temperature control unit, adjusting the refractive index of the laser resonant cavity to achieve subtle wavelength drift compensation.

[0040] After the calibration unit completes the calibration operation, the system automatically generates a calibration parameter set containing current correction parameters, temperature compensation parameters, and wavelength shift correction factors, and then verifies this parameter set. The verification process includes re-acquiring the standard gas signal, calculating the new concentration deviation and wavelength drift, and determining that the calibration is successful when both fall back to the corresponding threshold range. Subsequently, the calibration parameter set is applied to the subsequent data processing flow to compensate for the real-time acquired measurement signals, correcting system errors caused by temperature, aging, and optical attenuation, and finally generating the concentration value of the gas to be measured.

[0041] Furthermore, the method involves automatically calibrating the mining laser gas detector using the calibration unit, generating a calibration parameter set, calculating the measurement signal, and generating the concentration value of the gas to be measured. The calibration unit is activated in response to the calibration activation command. The calibration unit includes a laser drive current correction module and a temperature control compensation module. The laser drive current correction module is calibrated based on the concentration deviation value and the wavelength drift to obtain current amplitude adjustment parameters. The temperature control compensation module is calibrated based on the concentration deviation value and the wavelength drift to obtain temperature fine-tuning parameters. The current amplitude adjustment parameters and the temperature fine-tuning parameters are used as calibration commands to automatically calibrate the mining laser gas detector, generating a calibration parameter set. The calibration parameter set is verified. When the verification is successful, the calibration parameter set is applied to the measurement signal for compensation calculation to generate the concentration value of the gas to be measured.

[0042] After determining that the automatic calibration trigger conditions are met, the system responds to the calibration activation command and starts the calibration unit. The calibration unit includes a laser drive current correction module and a temperature control compensation module. The calibration unit is connected to the laser drive module and the temperature control module via a control bus, enabling fine-tuning of the laser's output characteristics and cavity temperature.

[0043] The laser drive current correction module is calibrated based on the concentration deviation and wavelength drift to obtain current amplitude adjustment parameters. Specifically, the system determines the shift trend of the laser output spectrum according to the direction and amplitude of the wavelength drift. If the wavelength drifts towards longer wavelengths, the drive current amplitude is appropriately reduced; if it drifts towards shorter wavelengths, the drive current is appropriately increased. This adjustment process employs a closed-loop iterative algorithm, using the second harmonic peak position as a feedback signal to dynamically correct the amplitude and modulation depth of the drive current, ensuring that the output wavelength is relocked to the center position of the gas absorption spectral line.

[0044] The temperature control compensation module is calibrated based on the concentration deviation and wavelength drift to obtain temperature fine-tuning parameters. The temperature control compensation module achieves precise temperature control by adjusting the operating current of the semiconductor thermoelectric cooler within the laser cavity. The system calculates the temperature fine-tuning amount based on the coupling relationship between the concentration deviation and wavelength drift, performing small-step compensation to eliminate the influence of ambient temperature fluctuations on the refractive index of the laser resonant cavity, thereby improving wavelength locking accuracy.

[0045] After obtaining the current amplitude adjustment parameters and temperature fine-tuning parameters, the system synchronously sends both as calibration commands to the laser drive current correction module and the temperature control compensation module to automatically calibrate the mining laser gas detector. After execution, the system generates a calibration parameter set containing current correction coefficients, temperature compensation factors, and wavelength correction vectors to describe the device's current self-calibration status. Subsequently, the calibration parameter set is verified. The verification process includes: acquiring the reference gas signal again after calibration, recalculating the concentration deviation and wavelength drift; when both fall back to the corresponding threshold range, the calibration result is deemed valid. After successful verification, the calibration parameter set is applied to subsequent signal processing to compensate for the real-time acquired measurement signals, thereby generating the corrected concentration value of the gas to be measured.

[0046] In summary, the embodiments of this application have at least the following technical effects: First, the mining laser gas detector is activated to generate detection beam parameters, which are then divided into measurement beam parameters and reference beam parameters. Next, the measurement beam parameters are passed through the area of ​​the gas to be measured to acquire a measurement signal, while the reference beam parameters are passed through a reference gas chamber to acquire a reference signal containing reference data values. Further, based on the measurement signal, photoelectric conversion calculations are performed on the reference signal to obtain the gas concentration detection value. Then, the gas concentration detection value is compared and analyzed with the reference data value according to the center wavelength position of the mining laser gas detector, and the calibration unit is activated based on the comparison result. Finally, the calibration unit automatically calibrates the mining laser gas detector, generating a calibration parameter set to calculate the measurement signal and generate the gas concentration value to be measured. This solves the technical problems of low calibration efficiency and unstable calibration accuracy in existing mining laser gas detectors, achieving the technical effect of automatic calibration of mining laser gas detectors and improving calibration efficiency and accuracy.

[0047] Example 2, based on the same inventive concept as the automatic calibration method of the mining laser gas detector in the foregoing examples, such as... Figure 2 As shown, this application provides an automatic calibration system for a mining laser gas detector, wherein the system includes: Parameter generation component 11: Activates the mining laser gas detector to generate detection beam parameters, dividing the detection beam parameters into measurement beam parameters and reference beam parameters; Signal acquisition component 12: Allows the measurement beam parameters to pass through the area of ​​the gas to be measured to acquire a measurement signal, and allows the reference beam parameters to pass through the reference gas chamber to acquire a reference signal, the reference signal containing reference data values; Calculation component 13: Performs photoelectric conversion calculation on the reference signal based on the measurement signal to obtain the gas concentration detection value; Comparison and analysis component 14: Compares and analyzes the gas concentration detection value with the reference data value according to the center wavelength position of the mining laser gas detector, and activates the calibration unit based on the comparison result; Correction component 15: Automatically corrects the mining laser gas detector through the calibration unit, generates a correction parameter set to calculate the measurement signal, and generates the gas concentration value to be measured.

[0048] Furthermore, the parameter generation component 11 is used to perform the following method: A bias current signal is generated by sending instructions to a digital-to-analog converter via a microcontroller; the bias current signal drives the mining laser gas detector to generate infrared detection beam parameters; the infrared detection beam parameters are coupled to a beam splitting optical unit, and the beam splitting optical unit divides the infrared detection beam parameters into two independently propagating beam parameters according to a preset energy ratio to obtain the measurement beam parameters and the reference beam parameters.

[0049] Furthermore, the signal acquisition component 12 is used to perform the following method: The measurement beam parameters are guided through the gas region to obtain the gas parameters; the gas parameters absorb the measurement beam parameters to generate an outgoing measurement beam parameter; the outgoing measurement beam parameter is received by a measurement photodetector and converted to generate a first electrical signal, which is the measurement signal; the reference beam parameters are guided through a reference gas chamber to generate an outgoing reference beam parameter; the outgoing reference beam parameter is received by a reference photodetector and converted to generate a second electrical signal, which is the reference signal.

[0050] Furthermore, the computing component 13 is used to perform the following methods: The first and second electrical signals are respectively input into a low-noise transimpedance amplifier for conversion and amplification to obtain a first voltage signal and a second voltage signal. Based on the first and second voltage signals, a high-speed analog-to-digital conversion is performed to obtain a digital measurement signal and a digital reference signal. The digital reference signal is amplified by lock-in to extract the second harmonic component. The mine laser gas detector is locked in real time according to the second harmonic component to determine the center wavelength parameter of the mine laser gas detector. Harmonic analysis is performed on the digital measurement signal according to the center wavelength parameter to extract the first and second harmonic components of the digital measurement signal. The amplitude of the first and second harmonic components of the digital measurement signal is analyzed to obtain the amplitude ratio. The gas concentration detection value is then calculated.

[0051] Furthermore, the computing component 13 is used to perform the following methods: The modulation frequency of the mining laser gas detector is retrieved, and the modulation frequency is mapped to the digital domain for same-frequency analysis to extract the sine reference signal and cosine reference signal. The digital reference signal is multiplied by the sine reference signal to obtain a first product signal. The digital reference signal is multiplied by the cosine reference signal to obtain a second product signal. The first product signal and the second product signal are digitally low-pass filtered to obtain the real part data and imaginary part data of the second harmonic. The second harmonic component of the digital reference signal is calculated based on the real part data and the imaginary part data of the second harmonic.

[0052] Furthermore, the computing component 13 is used to perform the following methods: The amplitude ratio is obtained by dividing the second harmonic amplitude of the digital measurement signal by the first harmonic amplitude of the digital measurement signal; a concentration-amplitude ratio calibration curve is constructed based on a standard gas with a known concentration; the amplitude ratio is linearly interpolated on the concentration-amplitude ratio calibration curve, and the gas concentration detection value is determined based on the interpolation result.

[0053] Furthermore, the comparison analysis component 14 is used to perform the following methods: The system continuously monitors the second harmonic peak position of the digital reference signal and determines the center wavelength position of the mining laser gas detector based on the second harmonic peak position of the digital reference signal. It then performs a first comparison between the detected gas concentration value and a standard concentration reference value to calculate the concentration deviation. Next, it performs a second comparison between the center wavelength position of the mining laser gas detector and a calibrated wavelength reference value to calculate the wavelength drift. The system then compares the concentration deviation value with a first preset threshold and the wavelength drift with a second preset threshold. When the concentration deviation value continuously exceeds the first preset threshold and / or the wavelength drift continuously exceeds the second preset threshold, it extracts a first duration of continuous exceedance and a second duration of continuous exceedance. When both the first duration of continuous exceedance and the second duration of continuous exceedance reach a preset stable duration, it generates a calibration activation command. The calibration activation command is sent to the calibration unit, triggering the calibration unit to enter a standby state to prepare for the execution of an automatic calibration program.

[0054] Furthermore, the comparison analysis component 14 is used to perform the following methods: The first preset threshold is a relative threshold used to determine whether the concentration measurement accuracy is out of tolerance; the second preset threshold is an absolute threshold used to determine whether the wavelength of the mining laser gas detector has drifted; if the absolute value of the concentration deviation is greater than the first preset threshold, or the absolute value of the wavelength drift is greater than the second preset threshold, it is determined to be a preliminary abnormality.

[0055] Furthermore, the correction component 15 is used to perform the following method: The calibration unit is activated in response to the calibration activation command. The calibration unit includes a laser drive current correction module and a temperature control compensation module. The laser drive current correction module is calibrated based on the concentration deviation value and the wavelength drift to obtain current amplitude adjustment parameters. The temperature control compensation module is calibrated based on the concentration deviation value and the wavelength drift to obtain temperature fine-tuning parameters. The current amplitude adjustment parameters and the temperature fine-tuning parameters are used as calibration commands to automatically calibrate the mining laser gas detector, generating a calibration parameter set. The calibration parameter set is verified. When the verification is successful, the calibration parameter set is applied to the measurement signal for compensation calculation to generate the concentration value of the gas to be measured.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An automatic calibration method for a mining laser gas detector, characterized in that, The method includes: The mining laser gas detector is activated to generate detection beam parameters, which are then divided into measurement beam parameters and reference beam parameters. The measurement beam parameters are passed through the gas region to obtain a measurement signal, and the reference beam parameters are passed through the reference gas cell to obtain a reference signal, which includes reference data values. Based on the measured signal, the reference signal is photoelectrically converted and calculated to obtain the gas concentration detection value; The gas concentration detection value is compared and analyzed with the reference data value according to the center wavelength position of the mining laser gas detector, and the calibration unit is activated based on the comparison result; The calibration unit automatically calibrates the mine laser gas detector, generates a set of calibration parameters, calculates the measurement signal, and generates the concentration value of the gas to be measured.

2. The automatic calibration method for the mining laser gas detector as described in claim 1, characterized in that, Activating a mining laser gas detector to generate detection beam parameters, and dividing the detection beam parameters into measurement beam parameters and reference beam parameters, the method includes: A bias current signal is generated by sending instructions to the digital-to-analog converter via a microcontroller. The bias current signal drives the mining laser gas detector to generate infrared detection beam parameters. The infrared detection beam parameters are coupled to a beam-splitting optical unit, which then splits the infrared detection beam parameters into two independently propagating beam parameters according to a preset energy ratio, thereby obtaining the measurement beam parameters and the reference beam parameters.

3. The automatic calibration method for the mining laser gas detector as described in claim 1, characterized in that, The method involves passing the measurement beam parameters through the region of the gas to be measured to obtain a measurement signal, and passing the reference beam parameters through a reference gas cell to obtain a reference signal. The measurement beam is guided through the region of the gas to be measured to obtain the parameters of the gas to be measured; The parameters of the gas to be measured are subjected to spectral absorption by the parameters of the measurement beam to generate the parameters of the outgoing measurement beam. The parameters of the emitted measurement beam are received by a photodetector and converted to generate a first electrical signal, which is the measurement signal. The reference beam parameters are guided through the reference gas chamber to generate the outgoing reference beam parameters; The parameters of the emitted reference beam are received by a reference photodetector and converted to generate a second electrical signal, which is the reference signal.

4. The automatic calibration method for the mining laser gas detector as described in claim 3, characterized in that, The method involves performing photoelectric conversion calculations on the reference signal based on the measured signal to obtain the gas concentration detection value, and includes: The first electrical signal and the second electrical signal are respectively input into a low-noise transimpedance amplifier for conversion and amplification to obtain a first voltage signal and a second voltage signal. High-speed analog-to-digital conversion is performed based on the first voltage signal and the second voltage signal to obtain digital measurement signal and digital reference signal; The digital reference signal is amplified by lock-in to extract the second harmonic component, and the mine laser gas detector is locked in real time according to the second harmonic component to determine the center wavelength parameter of the mine laser gas detector. Harmonic analysis is performed on the digital measurement signal according to the center wavelength parameter to extract the first harmonic component and the second harmonic component of the digital measurement signal. The amplitude of the first harmonic component and the second harmonic component of the digital measurement signal are analyzed to obtain the amplitude ratio. The gas concentration is then calculated to obtain the gas concentration detection value.

5. The automatic calibration method for a mining laser gas detector as described in claim 4, characterized in that, The method for extracting the second harmonic component of the digital reference signal by performing lock-in amplification includes: The modulation frequency of the mining laser gas detector is retrieved, and the modulation frequency is mapped to the digital domain for same-frequency analysis to extract the sine reference signal and cosine reference signal. The digital reference signal is multiplied by the sinusoidal reference signal to obtain the first product signal; The digital reference signal is multiplied by the cosine reference signal to obtain the second product signal; The first product signal and the second product signal are digitally low-pass filtered to obtain the real part data and the imaginary part data of the second harmonic; The second harmonic component of the digital reference signal is obtained by calculating based on the real part data and the imaginary part data of the second harmonic.

6. The automatic calibration method for the mining laser gas detector as described in claim 4, characterized in that, The method involves performing amplitude analysis on the first harmonic component and the second harmonic component of the digital measurement signal to obtain the amplitude ratio, and then calculating the gas concentration detection value. The amplitude ratio is obtained by dividing the second harmonic amplitude of the digital measurement signal by the first harmonic amplitude of the digital measurement signal. Calibration is performed based on a standard gas, and a concentration-amplitude ratio calibration curve is constructed, wherein the standard gas has a known concentration. The amplitude ratio is linearly interpolated on the concentration-amplitude ratio calibration curve, and the gas concentration detection value is determined based on the interpolation result.

7. The automatic calibration method for the mine laser gas detector as described in claim 4, characterized in that, The gas concentration detection value is compared and analyzed with the reference data value according to the center wavelength position of the mining laser gas detector, and the calibration unit is activated based on the comparison result. The method includes: The position of the second harmonic peak of the digital reference signal is continuously monitored, and the center wavelength position of the mining laser gas detector is determined according to the position of the second harmonic peak of the digital reference signal. The gas concentration detection value is compared with the standard concentration reference value to calculate the concentration deviation value. The center wavelength position of the mining laser gas detector is compared with the calibrated wavelength reference value in a second comparison to calculate the wavelength drift. The concentration deviation value is compared with a first preset threshold, and the wavelength drift is compared with a second preset threshold. When the concentration deviation value continuously exceeds the first preset threshold and / or the wavelength drift continuously exceeds the second preset threshold, the first duration of continuous exceedance and the second duration of continuous exceedance are extracted. When both the first duration of continuous exceedance and the second duration of continuous exceedance reach a preset stable duration, a calibration activation command is generated. The calibration activation command is sent to the calibration unit, triggering the calibration unit to enter standby mode to prepare for the execution of the automatic calibration procedure.

8. The automatic calibration method for a mining laser gas detector as described in claim 7, characterized in that, Before determining the concentration deviation value against a first preset threshold and the wavelength shift amount against a second preset threshold, the method includes: The first preset threshold is a relative threshold used to determine whether the concentration measurement accuracy is out of tolerance; The second preset threshold is an absolute threshold used to determine whether the wavelength of the mining laser gas detector has drifted. If the absolute value of the concentration deviation is greater than the first preset threshold, or the absolute value of the wavelength drift is greater than the second preset threshold, then it is determined to be a preliminary abnormality.

9. The automatic calibration method for a mining laser gas detector as described in claim 7, characterized in that, The calibration unit automatically calibrates the mining laser gas detector, generates a calibration parameter set, calculates the measurement signal, and generates the concentration value of the gas to be measured. The method includes: The calibration unit is activated in response to the calibration activation command. The calibration unit includes a laser drive current correction module and a temperature control compensation module. The laser drive current correction module is calibrated based on the concentration deviation value and the wavelength drift to obtain the current amplitude adjustment parameters; The temperature control compensation module is calibrated based on the concentration deviation value and the wavelength drift to obtain temperature fine-tuning parameters. The current amplitude adjustment parameter and the temperature fine-tuning parameter are used as calibration commands to automatically calibrate the mining laser gas detector and generate a calibration parameter set. The calibration parameter set is verified. Once the verification is successful, the calibration parameter set is applied to the measurement signal for compensation calculation to generate the concentration value of the gas to be measured.

10. An automatic calibration system for a mining laser gas detector, characterized in that, An automatic calibration method for implementing the mining laser gas detector according to any one of claims 1-9, the system comprising: Parameter generation component: Activate the mining laser gas detector to generate detection beam parameters, and divide the detection beam parameters into measurement beam parameters and reference beam parameters; Signal acquisition component: The measurement beam parameter passes through the gas region to acquire a measurement signal, and the reference beam parameter passes through the reference gas cell to acquire a reference signal, wherein the reference signal contains reference data values; Calculation component: Based on the measurement signal, the reference signal is converted into a photoelectric value to obtain the gas concentration detection value; Comparison and analysis component: The gas concentration detection value is compared and analyzed with the reference data value according to the center wavelength position of the mining laser gas detector, and the calibration unit is activated based on the comparison result; Calibration component: The calibration unit automatically calibrates the mining laser gas detector, generates a set of calibration parameters, calculates the measurement signal, and generates the concentration value of the gas to be measured.

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