An integrated multi-sensor working face safety state real-time perception and alarm system

Abstract

This invention discloses a real-time sensing and alarm system for the safety status of a working face integrating multiple sensors. The system includes a broadband light source, a pump laser, a grating demodulator, a centralized control server, an optical coupler, armored optical fiber, a cross-modal physical actuation sensing probe, and an explosion-proof linkage control box. The probe integrates a cascaded temperature compensation grating, a strain sensing grating, and a gas actuation grating. The gas actuation grating is housed in a constant-volume cavity with a gas-sensitive material and a photothermal micro / nano coating. Geometric constraints are used to convert the volume expansion of the gas-sensitive material into axial tensile stress on the grating. The centralized control server orthogonally decouples multiple wavelength drift signals using a third-order forward sensing matrix equation, outputting ambient temperature, structural strain, and gas concentration variables. When variables exceed limits, the power supply is physically cut off via the explosion-proof linkage control box. Furthermore, the pump light triggers photothermal desorption to eliminate hysteresis and achieve dynamic zero-point reset. This invention achieves passive sensing and hard-wired linkage control of multiple parameters in a mine.

Description

Technical Field

[0001] This invention relates to the field of coal mine safety monitoring technology, specifically to a real-time sensing and alarm system for the safety status of a working face that integrates multiple sensors. Background Technology

[0002] Coal mine underground working faces are high-risk areas for safety accidents such as gas outbursts and roof collapses. In order to ensure the safe production of mines, it is necessary to sense and monitor key parameters such as the concentration of dangerous gases such as gas in the working face environment, the structural stress deformation of large equipment, and the ambient temperature in real time. Fiber optic sensing technology has become an important technical means for condition monitoring in high-risk industrial sites due to its inherent safety, resistance to electromagnetic interference, and ease of long-distance serial multiplexing.

[0003] In existing multi-parameter monitoring systems in coal mines, fiber Bragg grating sensors are typically used to acquire environmental and equipment information. In practical applications, technicians place packaged fiber Bragg grating sensors on hydraulic supports, roadway sidewalls, or power distribution areas. When external physical or chemical quantities change, it causes changes in the effective refractive index of the fiber Bragg grating core or the grating period, resulting in a shift in the center wavelength of its reflection spectrum. The grating demodulation equipment located on the ground continuously collects these center wavelength shift data, performs conversion using a preset scaling factor, and then obtains the corresponding temperature, strain, or gas concentration values ​​at the working face, which serve as the basis for safety early warning.

[0004] However, existing multi-parameter monitoring technologies in coal mines typically employ dual-wavelength methods or reference grating methods to address temperature compensation. But in the complex underground environment, when a third environmental variable (such as methane concentration) needs to be simultaneously introduced for monitoring, existing dual-grating temperature compensation schemes cannot maintain high-precision orthogonal decoupling under multi-physics coupling conditions. Furthermore, existing chemical gas-sensitive coatings generally exhibit physical adsorption saturation hysteresis and mechanical stress relaxation after long-term adsorption of target gases. Once adsorption saturation occurs, they cannot automatically desorb and reset, leading to severe drift of the measurement zero point. Summary of the Invention

[0005] The technical problem this invention aims to solve is the deficiency of existing fiber Bragg grating monitoring technology in complex multi-field environments due to multivariate cross-sensitivity interference, and the difficulty of zero-point drift and inability to automatically reset after the gas-sensitive coating becomes saturated. Because environmental temperature fluctuations, equipment deformation, and the emission of hazardous gases simultaneously affect the sensing optical path, conventional demodulation systems lack a multi-dimensional orthogonal decoupling model, leading to false alarms and missed alarms in safety warnings.

[0006] The first aspect of this invention provides a real-time sensing and alarm system for the safety status of a working face that integrates multiple sensors. This system enables synchronous monitoring and safety linkage of temperature, strain, and gas concentration at the mine working face.

[0007] The system includes a broadband light source, a pump laser, an optical coupler, a grating demodulator, and a centralized control server at the ground control center, as well as a downhole cross-modal physical actuation sensing probe and an explosion-proof linkage control box connected via armored optical fiber. The cross-modal physical actuation sensing probe integrates a temperature compensation grating, a strain sensing grating, and a gas actuation grating. The temperature compensation grating achieves mechanical stress isolation through a micro capillary steel tube; the strain sensing grating is directly fixed to the displacement node of the hydraulic support; and the gas actuation grating is set in a constant volume cavity filled with gas-sensitive material.

[0008] This invention utilizes the geometric constraint mechanism inside a constant-volume cavity to convert the volume expansion caused by the adsorption of target gas by the gas-sensitive material into the linear displacement of the force-bearing slider, thereby applying axial tensile stress to the gas-actuated grating. Specifically, the axial tensile deformation of the gas-actuated grating driven by the slider is directly proportional to the product of the initial volume of the gas-sensitive material, the concentration volume expansion coefficient, and the target gas concentration, and inversely proportional to the effective force-bearing cross-sectional area of ​​the slider. Through this structure, chemical concentration information is converted into mechanical strain information of the fiber Bragg grating, realizing chemical parameter sensing under passive conditions.

[0009] The second aspect of the present invention provides a method for real-time perception and alarm of the working face safety status based on the above system. This method eliminates cross-sensitive interference between temperature, strain and gas concentration by constructing a third-order forward sensing matrix equation.

[0010] The centralized control server constructs a third-order forward sensing matrix equation, expressing the center wavelength drift of the three gratings as a linear superposition of the ambient temperature variable, structural strain variable, and target gas concentration variable. First, the centralized control server calculates the ambient temperature variable using the ratio of the wavelength drift of the temperature-compensated grating to the temperature sensitivity coefficient. Then, it substitutes the ambient temperature variable into the linear equation of the strain-sensing grating, subtracts the wavelength drift error caused by temperature fluctuations, and calculates the structural strain variable. Finally, it substitutes the ambient temperature variable into the linear equation of the gas-actuated grating, and, combined with the concentration-actuated strain proportionality coefficient, solves for the target gas concentration variable.

[0011] The centralized control server compares the calculated structural strain variable with the mechanical yield deformation threshold and the target gas concentration variable with the lower explosive limit concentration threshold. When the structural strain variable is greater than or equal to the mechanical yield deformation threshold, or the target gas concentration variable is greater than or equal to the lower explosive limit concentration threshold, the centralized control server generates an over-limit power-off command and sends the over-limit power-off command to the explosion-proof linkage control box, which then cuts off the power supply circuit of the working face power equipment.

[0012] In addition, the centralized control server synchronously performs time derivative calculations on the target gas concentration variable. When the rate of change of the target gas concentration is lower than the hysteresis judgment threshold within the preset time window and the target gas concentration variable is greater than zero, it is determined that the gas-sensitive material has entered the adsorption saturation state. The centralized control server sends a start signal to the pump laser and outputs a high-energy pump beam. The photothermal micro-nano coating in the constant volume cavity absorbs the high-energy pump beam and generates heat, causing the gas-sensitive material to be heated and undergo gas desorption. After the pump laser stops outputting, when the ambient temperature returns to the initial steady state, the centralized control server reads the real-time center wavelength of the current gas actuation grating and records it as the calibration wavelength, and replaces the original initial center wavelength, completing the zero-point reset.

[0013] The present invention, by adopting the above technical solution, can bring the following beneficial effects:

[0014] 1. This invention cascades structurally differentiated temperature compensation gratings, strain sensing gratings, and gas actuation gratings with constant volume cavity constraints along the axial direction on armored optical fibers. It also performs inverse matrix orthogonal decoupling operations using a third-order forward sensing matrix equation constructed within a centralized control server. This decomposes the mutually interfering center wavelength drift signals in the complex multi-field environment of the working face into linearly independent environmental temperature variables, structural strain variables, and target gas concentration variables. From the physical mechanism and algorithm level, this invention eliminates the cross-sensitive interference defect of fiber Bragg grating sensors in multi-physics field monitoring, achieving a precise all-time decoupling sensing effect for multi-field coupled safety parameters of the coal mine working face using a single sensing link.

[0015] 2. This invention designs a rigid constant-volume cavity physical structure integrating gas-sensitive materials and micro-slider guide rail components. It converts the three-dimensional volume expansion increment after the chemically sensitive material adsorbs the target gas into a quasi-static mechanical strain physical quantity that drives the force-bearing slider to make linear displacement. The real-time concentration variable calculated by the centralized control server directly drives the protocol parsing module and relay drive circuit inside the explosion-proof linkage control box. This enables the vacuum contactor to immediately physically disconnect the main power supply circuit of the high-power equipment at the working face when it detects structural strain or gas concentration exceeding the limit. This completely eliminates the monitoring failure hazard of electrical sensors in flammable and explosive complex environments, and achieves the safety control effect of essentially passive front-end disaster perception and hard-wired linkage at the end of alarm execution at the coal mine working face.

[0016] 3. This invention utilizes a central control server to perform time derivative determination logic on the real-time calculated target gas concentration change rate, thereby driving a pump laser to convert the high-energy pump beam energy into heat through photothermal conversion effect to accelerate the active desorption and reset process of the gas-sensitive material. After the ambient temperature recovers to the steady-state determination time window, the current center wavelength value is extracted and the initial calibration parameters in the underlying database are overwritten in real time. This effectively solves the problem of zero-point drift caused by physical adsorption saturation hysteresis and mechanical stress relaxation that is common in chemically actuated sensors. It also realizes the active self-healing performance of the sensor during long-term operation in harsh downhole environments and the dynamic automatic reset effect of the measurement baseline. Attached Figure Description

[0017] Figure 1 This is a hardware topology diagram of the multi-sensor integrated real-time sensing and alarm system for the safety status of the working surface in this invention.

[0018] Figure 2 This is a flowchart of the multi-parameter passive sensing method for the working surface based on photothermal-chemical synergy of the present invention;

[0019] Figure 3 This is a diagram of the cross-modal physical actuation sensing probe of the present invention;

[0020] Figure 4 This is a surface view of the internal structure of the constant-volume cavity and the photothermal-gas-sensitive cross-modal coupling mechanism of the present invention;

[0021] Figure 5 This is a diagram of the hard-wired linkage electrical structure for passive sensing to active disconnection according to the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] See attached document Figure 1-5 The present invention provides a real-time sensing and alarm system for the safety status of a working surface that integrates multiple sensors, including: a broadband light source 10, a pump laser 20, a grating demodulator 30, a centralized control server 40, an optical coupler 50, an armored optical fiber 60, a cross-modal physical actuation sensing probe 70, and an explosion-proof linkage control box 80.

[0025] The output of the broadband light source 10 and the output of the pump laser 20 are respectively connected to the input of the optical coupler 50. The output of the optical coupler 50 is connected to the input of the armored fiber 60. The receiving end of the grating demodulator 30 is connected to the armored fiber 60 through the optical coupler 50. The central control server 40 is connected to the grating demodulator 30 and the pump laser 20 through data cables. The central control server 40 is connected to the explosion-proof linkage control box 80 through industrial Ethernet. The explosion-proof linkage control box 80 is connected in series with the power supply circuit of the working face power equipment.

[0026] Broadband light source 10, pump laser 20, grating demodulator 30, central control server 40 and optical coupler 50 are set in the ground control center, armored optical fiber 60 is laid along the hydraulic support of the working face, and explosion-proof linkage control box 80 is set in the explosion-proof power distribution area underground.

[0027] Multiple cross-modal physical actuation sensing probes 70 are configured, and the multiple cross-modal physical actuation sensing probes 70 are connected in series along the extension direction of the armored optical fiber 60 into the optical path of the armored optical fiber 60.

[0028] The cross-modal physical actuation sensing probe 70 includes a temperature compensation grating 71, a strain sensing grating 72, a gas actuation grating 73, and a constant volume cavity 74. The temperature compensation grating 71, the strain sensing grating 72, and the gas actuation grating 73 are cascaded sequentially along the core axis of the armored optical fiber 60. The temperature compensation grating 71, the strain sensing grating 72, and the gas actuation grating 73 have non-overlapping initial center wavelengths.

[0029] The temperature compensation grating 71 is encapsulated in a micro capillary tube. One end of the micro capillary tube is fixed to the inner wall of the housing of the cross-modal physical actuation sensing probe 70, and the other end of the micro capillary tube is suspended. The two ends of the fiber core of the temperature compensation grating 71 do not bear external axial stress and transverse shear force.

[0030] The two ends of the strain sensing grating 72 are fixedly installed on the two relative displacement nodes of the hydraulic support of the working face, and the fiber core axis of the strain sensing grating 72 is parallel to the direction of the force deformation of the hydraulic support of the working face.

[0031] The gas-actuated grating 73 is disposed in the constant volume cavity 74, which is a rigid sealed shell structure with a fixed internal volume. The constant volume cavity 74 is filled with a gas-sensitive material 75, and the inner wall of the constant volume cavity 74 is deposited with a photothermal micro-nano coating 76.

[0032] The gas-sensitive material 75 is located within the volume constraint space of the constant volume cavity 74. The constant volume cavity 74 is equipped with a micro slider guide rail assembly, which includes a slider and a guide rail. One end of the gas-sensitive material 75 abuts against the inner wall of the constant volume cavity 74, and the other end of the gas-sensitive material 75 is attached to the slider. The slider is slidably mounted on the guide rail, and the slider is connected to the end of the gas actuation grating 73.

[0033] The internal geometric constraints of the constant-volume cavity 74 convert the volume expansion of the gas-sensitive material 75 into unidirectional linear displacement, and the axial tensile deformation of the gas-actuated grating 73 caused by the slider drive. satisfy:

[0034]

[0035] in, The initial volume of the gas-sensitive material (75) is given. The concentration volume expansion coefficient of the gas-sensitive material (75) is given. The coefficient of volumetric thermal expansion of the gas-sensitive material (75) is given. For the ambient temperature variable, For the target gas concentration variable, This is the effective cross-sectional area of ​​the slider under force.

[0036] The photothermal micro-nano coating 76 is located within the photothermal field radiation region of the armored optical fiber 60. The central control server 40 controls the pump laser 20 to output pump light. The pump light is transmitted to the constant volume cavity 74 via the optical coupler 50 and the armored optical fiber 60. The photothermal micro-nano coating 76 absorbs the pump light and generates heat. The heat is conducted to the surface of the gas-sensitive material 75, causing the gas-sensitive material 75 to undergo a gas desorption process.

[0037] A broadband light source 10 emits a sensing beam, which is transmitted via armored optical fiber 60 to each cross-modal physical actuation sensing probe 70. Temperature compensation grating 71, strain sensing grating 72 and gas actuation grating 73 respectively reflect narrowband light signals corresponding to their center wavelengths. Grating demodulator 30 receives the narrowband light signals and extracts the center wavelength drift data of the grating. Central control server 40 receives the center wavelength drift data, performs analysis and calculation, and outputs action commands to explosion-proof linkage control box 80.

[0038] Furthermore, this embodiment provides a workflow for a real-time sensing and alarm system for the safety status of a work surface integrating multiple sensors, including:

[0039] In the initial state where there is no external stress on the working surface and no target gas infiltration, the system performs the initialization calibration steps. The broadband light source 10 outputs the sensing beam, and the grating demodulator 30 reads and records the initial center wavelength values ​​of the temperature compensation grating 71, the strain sensing grating 72 and the gas actuation grating 73. The initial center wavelength values ​​are stored in the central control server 40 as the reference data for wavelength drift calculation.

[0040] After the initial calibration step is completed, the system enters the real-time monitoring stage. The broadband light source 10 continuously outputs a broadband sensing beam, which is injected into the armored fiber 60 via the optical coupler 50. The armored fiber 60 transmits the broadband sensing beam to multiple transmodal physical actuation sensing probes 70 connected in series.

[0041] The temperature compensation grating 71, strain sensing grating 72 and gas actuation grating 73 inside the cross-modal physical actuation sensing probe 70 perform wavelength selective reflection of the broadband sensing beam, and the reflection process forms a narrowband reflected light signal containing environmental parameter information. The narrowband reflected light signal is transmitted in reverse along the armored optical fiber 60 and enters the grating demodulator 30 through the optical coupler 50.

[0042] The grating demodulator 30 analyzes the narrowband reflected light signal, extracts the real-time center wavelength data of the temperature compensation grating 71, the strain sensing grating 72 and the gas actuation grating 73, and sends the real-time center wavelength data to the central control server 40.

[0043] The central control server 40 receives real-time center wavelength data and calculates the center wavelength drift of the corresponding grating at the current moment. The central control server 40 uses the aforementioned center wavelength drift to perform orthogonal decoupling calculations and outputs ambient temperature variables, structural strain variables, and target gas concentration variables.

[0044] The centralized control server 40 compares the calculated structural strain variable and target gas concentration variable with the safety threshold envelope set inside the system. When the structural strain variable exceeds the preset mechanical yield deformation threshold, or the target gas concentration variable exceeds the preset lower explosive limit concentration threshold, the centralized control server 40 generates an over-limit action command.

[0045] The central control server 40 sends the over-limit action command to the explosion-proof linkage control box 80 in the underground area through the industrial Ethernet link. After receiving the over-limit action command, the explosion-proof linkage control box 80 triggers the internal relay module to disconnect the power supply circuit of the working face power equipment.

[0046] The centralized control server 40 synchronously performs time derivative calculation on the target gas concentration variable to obtain the target gas concentration change rate. When the target gas concentration change rate is lower than the set hysteresis judgment threshold within the preset time window and the absolute value of the target gas concentration variable is greater than zero, the centralized control server 40 determines that the gas sensitive material 75 in the cross-modal physical actuation sensing probe 70 has entered the adsorption saturation state.

[0047] After determining the adsorption saturation state, the central control server 40 sends a start-up level signal to the pump laser 20. The pump laser 20 outputs a high-energy pump beam of a specific wavelength. The high-energy pump beam is transmitted sequentially through the optical coupler 50 and the armored optical fiber 60 to the constant volume cavity 74 of the cross-modal physical actuation sensing probe 70.

[0048] The photothermal micro-nano coating 76 on the inner wall of the constant volume cavity 74 absorbs the high-energy pump beam and generates heat. The heat is conducted to the surface of the gas-sensitive material 75. The gas-sensitive material 75 undergoes gas desorption when heated, releasing the adsorbed target gas. The volume of the gas-sensitive material 75 shrinks back to its initial state.

[0049] The central control server 40 sends a stop signal to the pump laser 20, and the high-energy pump beam stops outputting. The central control server 40 continues to read the real-time center wavelength data of the temperature compensation grating 71 until the ambient temperature variable returns to the initial reference zero point.

[0050] After the temperature recovers, the central control server 40 reads the real-time center wavelength value fed back by the gas actuation grating 73. The central control server 40 then overwrites the real-time center wavelength value fed back at this time into the underlying database as the new initial center wavelength parameter of the gas actuation grating 73, thus completing the initial center wavelength update of the gas actuation grating 73.

[0051] Furthermore, this embodiment provides a physical cascade structure for a cross-modal physical actuation sensing probe 70, including:

[0052] The probe housing 701, the encapsulation flange 702, and the temperature compensation grating 71, the strain sensing grating 72, and the gas actuation grating 73 are cascaded sequentially along the extension direction of the armored optical fiber 60.

[0053] The probe housing 701 has encapsulation flanges 702 at both ends. The armored optical fiber 60 passes through the inside of the probe housing 701. The outer protective layer of the armored optical fiber 60 is cut off inside the probe housing 701 to form a bare optical fiber section. The temperature compensation grating 71, the strain sensing grating 72 and the gas actuation grating 73 are all engraved in the core of the bare optical fiber section. The temperature compensation grating 71, the strain sensing grating 72 and the gas actuation grating 73 are arranged in series axially on the bare optical fiber section.

[0054] A microcapillary tube 711 is sleeved on the outside of the bare optical fiber section where the temperature compensation grating 71 is located. The inner diameter of the microcapillary tube 711 is larger than the outer diameter of the bare optical fiber section. The bare optical fiber section is in a tension-free and straight state inside the microcapillary tube 711. The first end of the microcapillary tube 711 is fixed to the inner wall of the probe housing 701, and the second end of the microcapillary tube 711 is suspended inside the probe housing 701. The microcapillary tube 711 forms a mechanical stress isolation structure between the temperature compensation grating 71 and the probe housing 701.

[0055] The two ends of the bare optical fiber section where the strain sensing grating 72 is located are respectively provided with a first anchor point 721 and a second anchor point 722. The first anchor point 721 and the second anchor point 722 are fixedly connected to the side wall of the probe housing 701. The side wall of the probe housing 701 is in contact with the surface of the bearing structure of the working surface hydraulic support and is connected by fasteners. The mechanical deformation of the working surface hydraulic support is sequentially transmitted to the probe housing 701, the first anchor point 721 and the second anchor point 722. The fiber core of the strain sensing grating 72 generates axial tension synchronous with the mechanical deformation of the working surface hydraulic support.

[0056] A gas-actuated grating 73 passes through the internal space of a constant-volume cavity 74. A first fiber optic perforation and a second fiber optic perforation are formed on the outer wall of the constant-volume cavity 74. Bare fiber segments at both ends of the gas-actuated grating 73 are inserted into the first and second fiber optic perforations, respectively. The first and second fiber optic perforations are filled with sealant 743, which seals and fixes the bare fiber segments to the outer wall of the constant-volume cavity 74. The constant-volume cavity 74 is fixedly disposed inside the probe housing 701, and is further fixed inside the probe housing 701 by a single-point cantilever buffer support structure. This single-point cantilever buffer support structure allows the constant-volume cavity 74 to float entirely within the housing cavity, thus physically decoupling and isolating the constant-volume cavity 74 and the internal gas-actuated grating 73 from the axial mechanical deformation of the probe housing 701 caused by the external hydraulic support. Target gas molecules enter the constant-volume cavity 74 through a waterproof and breathable membrane 742 and ventilation micropores 741.

[0057] Temperature-compensated grating 71, strain-sensing grating 72, and gas-actuated grating 73 satisfy the fiber Bragg diffraction condition, and the center wavelength of the gratings... satisfy:

[0058]

[0059] In the formula, The effective refractive index of the fiber core, The grating period is the grating period of the grating. The temperature compensation grating 71, the strain sensing grating 72 and the gas actuation grating 73 each have different grating period values. There is a wavelength interval between the center wavelengths of the temperature compensation grating 71, the strain sensing grating 72 and the gas actuation grating 73. The value of the wavelength interval is greater than the sum of the maximum wavelength drifts generated by each grating under the maximum measurement range. The wavelength interval is used to isolate the reflection spectrum of adjacent gratings.

[0060] Furthermore, it also includes: an elastic diaphragm transmission assembly 77, the constant volume cavity 74 has a cylindrical accommodating space inside, the elastic diaphragm transmission assembly 77 is disposed in the cylindrical accommodating space, the periphery of the elastic diaphragm transmission assembly 77 is rigidly sealed and fixed to the inner wall of the constant volume cavity 74, and its center has a degree of freedom to generate deflection displacement along the central axis of the constant volume cavity 74.

[0061] Gas-sensitive material 75 is filled in the columnar accommodating space and is located between the first sidewall of the constant volume cavity 74 and the elastic diaphragm transmission assembly 77. The first end face of the gas-sensitive material 75 is attached to the first sidewall, and the second end face is attached to the force-bearing surface of the elastic diaphragm transmission assembly 77.

[0062] After the gas-sensitive material 75 adsorbs the target gas molecules, it expands in volume. Due to the radial constraint of the inner wall of the constant volume cavity, the volume expansion of the gas-sensitive material 75 is converted into a frictionless deflection displacement of the central node of the elastic diaphragm transmission assembly 77 in the direction away from the first side wall.

[0063] The elastic diaphragm drive assembly 77 has an optical fiber through hole at its center. The bare optical fiber section passes through the optical fiber through hole and is fixedly connected to the center displacement node of the elastic diaphragm drive assembly 77 at the optical fiber through hole by a second sealant.

[0064] The elastic diaphragm transmission assembly 77 deflects as the gas-sensitive material 75 expands, thereby applying axial tensile stress to the gas-actuated grating 73 and generating a chemical actuation strain that satisfies:

[0065]

[0066] In the formula, This refers to the axial tensile deformation of the gas-actuated grating 73 caused by the slider drive. This is the initial calibration length of the bare optical fiber segment between the first sidewall and the force-bearing slider 772;

[0067] A photothermal micro / nano coating 76 is coated on the inner wall of the columnar accommodating space of the constant volume cavity 74 and is arranged circumferentially around the periphery of the gas-sensitive material 75. A wavelength-selective coupling microstructure (e.g., a tilted fiber grating or a long-period fiber grating whose resonant wavelength matches the pump light band) is fabricated on the bare fiber segment next to the gas actuation grating 73 inside the constant volume cavity 74. The high-energy pump beam and the broadband sensing beam are configured in different non-overlapping frequency bands (e.g., the pump light in the 980nm band and the broadband sensing beam in the 1550nm C band). When the high-energy pump beam is transmitted to the bare fiber segment through the armored fiber 60, the pump light of a specific wavelength is directionally coupled out of the cladding and radiates to the surface of the photothermal micro / nano coating 76 through the wavelength-selective coupling microstructure, while the broadband sensing beam maintains total internal reflection and lossless transmission in this segment.

[0068] The photothermal micro-nano coating 76 absorbs the photon energy of the high-energy pump beam and generates heat. The heat is conducted to the gas-sensitive material 75, causing the gas-sensitive material 75 to heat up. The increased temperature reduces the binding energy between the gas-sensitive material 75 and the target gas molecules.

[0069] Gas-sensitive material 75 undergoes gas desorption, releasing adsorbed target gas molecules. The released target gas molecules are discharged from constant volume cavity 74 through waterproof and breathable membrane 742 and ventilated micropores 741. The volume of gas-sensitive material 75 shrinks, and the quartz elastic restoring force of gas-actuated grating 73 pulls the force-bearing slider 772 to slide in the opposite direction along linear guide rail 771. The force-bearing slider 772 resets towards the first sidewall, the axial tensile stress of gas-actuated grating 73 is relieved, and the center wavelength of gas-actuated grating 73 returns to the initial center wavelength.

[0070] Example 2

[0071] See attached document Figure 1-5 This invention provides a multiphysics orthogonal decoupling and parameter calculation algorithm, comprising:

[0072] The center wavelength of the temperature-compensated grating 71 is affected by ambient temperature. The influence causes drift, environmental temperature variables The thermo-optical effect causes a change in the refractive index of the fiber material on which the temperature compensation grating 71 is inscribed, and also causes thermal expansion of the fiber material. The temperature compensation grating 71 is encapsulated inside a micro-capillary steel tube 711 and is in a suspended state. The temperature compensation grating 71 is unaffected by external mechanical strain. The center wavelength shift of the temperature compensation grating 71 is... With ambient temperature variables The physical response relationship satisfies:

[0073]

[0074] In the formula, The initial center wavelength of the temperature compensation grating 71, The coefficient of thermal expansion of the optical fiber material. The thermo-optic coefficient of optical fiber material is defined as follows: The temperature sensitivity coefficient of the temperature compensation grating 71;

[0075] The center wavelength of the strain-sensing grating 72 is affected by ambient temperature. With structural strain variables Combined effect, structural strain variables The fiber segment inscribed with the strain-sensing grating 72 undergoes axial physical deformation, which alters the grating period of the strain-sensing grating 72 and changes the effective refractive index of the fiber core through the elasto-optic effect, resulting in a shift in the center wavelength of the strain-sensing grating 72. satisfy:

[0076]

[0077] In the formula, The initial center wavelength of the strain-sensing grating 72 is given. The effective elastic-optical coefficient of optical fiber material is defined as follows: The strain sensitivity coefficient of the strain sensing grating 72 is defined as follows: The temperature sensitivity coefficient of the strain sensing grating 72;

[0078] The center wavelength of the gas-actuated grating 73 is affected by ambient temperature. Chemically Actuated Strain Combined effect, chemically actuated strain The center wavelength shift of the gas-actuated grating 73 is caused by the volume expansion of the gas-sensitive material 75 after adsorbing target gas molecules. satisfy:

[0079]

[0080] In the formula, Define the initial center wavelength of the gas-actuated grating 73. The strain sensitivity coefficient of the gas-actuated grating 73 is defined as follows: The temperature sensitivity coefficient of the gas-actuated grating 73;

[0081] The volume expansion of the gas-sensitive material 75 after adsorbing target gas molecules is related to the change in target gas concentration. Relatedly, the force-bearing slider 772 converts the volume expansion into axial tension on the gas-actuated grating 73, resulting in chemically actuated strain. With target gas concentration The linear response relationship satisfies:

[0082]

[0083] In the formula, The concentration-induced strain proportionality coefficient of the gas-sensitive material 75. The value is determined by the physical parameters of the constant-volume cavity 74 and the gas-sensitive material 75, satisfying the calculation relationship:

[0084]

[0085] In the formula, The initial volume of the gas-sensitive material 75. The concentration volume expansion coefficient of the gas-sensitive material is 75. The effective cross-sectional area of ​​the force-bearing slider 772 is... This is the initial calibration length of the bare optical fiber segment between the first sidewall and the force-bearing slider 772;

[0086] The centralized control server 40 will use chemically actuated strain With target gas concentration Substituting the linear response relationship into the equation for the center wavelength drift of the gas-actuated grating 73, the center wavelength drift of the gas-actuated grating 73 is... With target gas concentration and ambient temperature variables The mathematical model satisfies:

[0087]

[0088] The centralized control server 40 extracts the mathematical models of the temperature compensation grating 71, the strain sensing grating 72, and the gas actuation grating 73. The centralized control server 40 determines that the ambient temperature variable is included in the formula for the center wavelength drift of each grating. The resulting wavelength drift term is used by the centralized control server 40 as the basis for constructing the forward sensing matrix equation using a mathematical model.

[0089] It should be noted that the additional axial mechanical tensile strain caused by the thermal expansion volume increase of the gas-sensitive material (75) due to temperature fluctuations is used as an ambient temperature parameter. The linear response term is uniformly and equivalently absorbed into the overall temperature sensitivity coefficient of the gas-actuated grating (73) in the above drift equation. Therefore, through subsequent inverse orthogonal decoupling operations, the cross-sensitivity interference caused by the intrinsic thermal expansion of the material and the interference from environmental temperature fluctuations can be completely eliminated.

[0090] Furthermore, the central control server 40 acquires the center wavelength drift of the temperature compensation grating 71, the strain sensing grating 72, and the gas actuation grating 73. The center wavelength drift is measured by the grating demodulator 30 and transmitted to the central control server 40. The central control server 40 internally stores sensitivity coefficient parameters, including the temperature sensitivity coefficient of the temperature compensation grating 71. Temperature sensitivity coefficient of strain sensing grating 72 The strain sensitivity coefficient of strain sensing grating 72 Temperature sensitivity coefficient of gas-actuated grating 73 and the strain sensitivity coefficient of the gas-actuated grating 73 The central control server 40 internally stores the concentration-induced strain proportionality coefficient of the gas-sensitive material 75. ;

[0091] The centralized control server 40 constructs a linear equation for wavelength drift based on the elasto-optic and thermo-optic effects of optical fibers. The temperature-compensated grating 71 is in a state without external axial stress, and its center wavelength drift is linearly proportional to the ambient temperature. The strain-sensing grating 72 is affected by the combined effects of the deformation of the hydraulic support on the working surface and ambient temperature fluctuations. Its center wavelength drift is a linear superposition of the periodic physical deformation of the grating caused by mechanical strain and the change in the refractive index of the fiber core caused by temperature changes. The gas-actuated grating 73, due to the single-point cantilever buffer structure of the constant-volume cavity, achieves physical decoupling from external mechanical strain and is therefore absolutely immune to external structural strain variables. The cross-interference of the center wavelength is only affected by the combined effect of the expansion of the gas-sensitive material 75 and the fluctuation of the ambient temperature. That is, the center wavelength drift of the gas-actuated grating 73 is strictly expressed as a linear superposition of chemical actuation strain and thermo-optic effect.

[0092] The central control server 40 combines the center wavelength drift, environmental variables, and sensitivity coefficient parameters to construct a third-order forward sensing matrix equation, which satisfies the following:

[0093]

[0094] In the formula, To compensate for the center wavelength shift of the temperature-compensated grating 71, The center wavelength shift of the strain sensing grating 72. This represents the center wavelength shift of the gas-actuated grating 73. For the ambient temperature variable, For structural strain variables, The target gas concentration variable;

[0095] The equation for the third-order forward sensing matrix contains a lower triangular matrix, and the main diagonal elements of the third-order forward sensing matrix are... , and All are non-zero, the third-order forward sensing matrix is ​​full rank and has a unique inverse matrix. The central control server performs inverse matrix operations on 40 pairs of third-order forward sensing matrices to generate an inverse orthogonal decoupling model.

[0096] The central control server 40 executes an inverse orthogonal decoupling model to separate cross-sensitive interferences between environmental variables, and the central control server 40 calculates the environmental temperature variable. Ambient temperature variables The computational relationship satisfies:

[0097]

[0098] The central control server 40 will control the ambient temperature variable. Substituting the wavelength drift linear equation of the strain-sensing grating 72 and eliminating the common-mode error caused by environmental temperature fluctuations, the centralized control server 40 calculates the structural strain variables. Structural strain variables The computational relationship satisfies:

[0099]

[0100] The central control server 40 will control the ambient temperature variable. Substituting the wavelength drift linear equation of the gas-actuated grating 73 and eliminating the common-mode error caused by ambient temperature fluctuations, the central control server 40 calculates the target gas concentration variable. Target gas concentration variable The computational relationship satisfies:

[0101]

[0102] Centralized control server 40 outputs ambient temperature variable Structural strain variables With the target gas concentration variable The value.

[0103] Furthermore, the central control server 40 internally stores safety threshold parameters, including the mechanical yield deformation threshold. With lower explosive limit concentration threshold The centralized control server 40 obtains the structural strain variables from the orthogonal decoupling calculation output. With the target gas concentration variable ;

[0104] The central control server 40 extracts the current time according to the preset sampling period. Structural strain variables With the current moment Target gas concentration variable The central control server 40 executes the early warning judgment logic, which takes the structural strain variables as an example. With mechanical yield deformation threshold Perform numerical comparisons and simultaneously update the target gas concentration variable. With lower explosive limit concentration threshold Perform numerical comparison;

[0105] The Boolean function corresponding to the early warning judgment logic Boolean functions The judgment relationship satisfies:

[0106]

[0107] In the formula, for Structural strain variables at time t, for The target gas concentration variable at any given time. The mechanical yield deformation threshold. This is the lower explosive limit concentration threshold. For logical OR operator;

[0108] when When the calculation result is 1, the central control server 40 determines that the working face is in a dangerous state, the central control server 40 generates an over-limit power cut-off command, and the central control server 40 writes the over-limit power cut-off command into the control output register.

[0109] when When the calculation result is 0, the central control server 40 determines that the working face is in a normal state, the central control server 40 does not output control commands, and the central control server 40 waits to read the center wavelength drift data of the next time period.

[0110] The central control server 40 encapsulates the over-limit power-off command into an industrial control protocol data packet through the industrial Ethernet communication interface, and sends the industrial control protocol data packet to the explosion-proof linkage control box 80.

[0111] The explosion-proof linkage control box 80 is equipped with a protocol parsing module and a relay drive circuit. The protocol parsing module receives and parses industrial control protocol data packets. The protocol parsing module outputs a trigger level to the relay drive circuit. The relay drive circuit receives the trigger level and controls the AC contactor of the working face power equipment to disconnect. The AC contactor physically cuts off the power supply circuit of the working face power equipment.

[0112] Example 3

[0113] See attached document Figure 1-5 The present invention provides a hard-wired linkage mechanism for passive sensing to active disconnection, comprising: an industrial Ethernet switch 81, a protocol parsing module 82, a relay drive circuit 83, an intermediate relay 84, a vacuum contactor 85, and an independent control power supply 86.

[0114] The network communication interface of the centralized control server 40 is connected to the industrial Ethernet switch 81 via a fiber optic link. The industrial Ethernet switch 81 is installed in the explosion-proof power distribution chamber underground. The industrial Ethernet switch 81 is connected to the protocol parsing module 82 via a shielded twisted pair cable. The protocol parsing module 82, the relay drive circuit 83, and the intermediate relay 84 are installed inside the shell of the explosion-proof linkage control box 80. The independent control power supply 86 is installed inside the shell of the explosion-proof linkage control box 80. The power output terminal of the independent control power supply 86 is connected to the power input terminal of the protocol parsing module 82 and the power input terminal of the relay drive circuit 83, respectively. The independent control power supply 86 is independent of the main power supply circuit of the working face power equipment.

[0115] The logic output pin of the protocol parsing module 82 is connected to the input terminal of the relay drive circuit 83. The drive output terminal of the relay drive circuit 83 is connected to the excitation coil of the intermediate relay 84. The normally closed contact of the intermediate relay 84 is connected in series to the control coil circuit of the vacuum contactor 85. The main contact of the vacuum contactor 85 is connected in series to the main power supply circuit of the working face power equipment.

[0116] After determining that the structural strain variable or the target gas concentration variable exceeds the limit, the centralized control server 40 generates a power-off control data packet that follows the industrial standard protocol. The power-off control data packet is routed to the protocol parsing module 82 through the industrial Ethernet switch 81. The protocol parsing module 82 performs data packet parsing and address verification on the power-off control data packet.

[0117] The protocol parsing module 82 extracts the instruction field information from the power failure control data packet. After verifying that the instruction field information is consistent with the preset hardware operation code, the protocol parsing module 82 changes the level state of the logic output pin from low level to high level, and the relay drive circuit 83 receives the high level signal.

[0118] The relay drive circuit 83 amplifies the high-level signal, and the DC current output by the relay drive circuit 83 flows to the excitation coil of the intermediate relay 84. The excitation coil of the intermediate relay 84 generates a magnetic field, and the armature of the intermediate relay 84 is attracted under the action of the magnetic field, causing its normally closed contact to open. The opening of the normally closed contact forcibly cuts off the control coil circuit of the vacuum contactor 85, causing the internal electromagnetic mechanism of the vacuum contactor 85 to lose its holding excitation. The main contacts of the vacuum contactor 85 are instantaneously released and opened under the action of the return spring. The main contacts of the vacuum contactor 85 physically disconnect the phase line of the power equipment on the working face, and the state variable of the main contacts of the vacuum contactor 85 changes. The logic output level variable of the protocol parsing module 82 The logical linkage relationship satisfies:

[0119]

[0120] In the formula, This indicates that the main contact is closed. This indicates that the main contact is open. For the logic output level variable of protocol parsing module 82, This is the trigger threshold voltage for the relay drive circuit 83;

[0121] After the centralized control server 40 sends out the power failure control data packet, it monitors the port status fed back by the industrial Ethernet switch 81 in real time. After the protocol parsing module 82 of the explosion-proof linkage control box 80 completes the level conversion action, it sends an execution confirmation signal back to the centralized control server 40. The independent control power supply 86, with its built-in explosion-proof battery pack, continues to provide working voltage to the protocol parsing module 82 within the rated safety endurance time after the vacuum contactor 85 cuts off the main power supply circuit. This ensures the hard-wired logic locking of the disaster protection status such as gas over-limit and the reliable transmission of the execution confirmation signal back to the ground. The centralized control server 40 receives the execution confirmation signal and updates the system status register.

[0122] Furthermore, this embodiment provides a method for hysteresis determination and photothermal actuation execution logic, including the following steps:

[0123] The centralized control server 40 acquires the target gas concentration variable from the orthogonal decoupling calculation output in real time. The centralized control server has 40 pairs of target gas concentration variables. The rate of change of the target gas concentration is calculated by performing time derivative calculations. The central control server 40 has a hysteresis detection threshold stored in its internal storage. With time window ;

[0124] Centralized control server 40 extracts continuous time windows Rate of change of target gas concentration within With the target gas concentration variable The central control server compares the rate of change of target gas concentration. The absolute value and the hysteresis threshold ;

[0125] The logic condition for the centralized control server 40 to determine that the gas-sensitive material 75 has entered the adsorption saturation hysteresis state is met:

[0126]

[0127] In the formula, For continuous time windows The absolute value of the rate of change of the internal target gas concentration. The set hysteresis detection threshold, The logical AND operator determines that when the logical condition is met, the centralized control server 40 determines that the gas-sensitive material 75 in the cross-modal physical actuation sensing probe 70 has entered the adsorption saturation hysteresis state.

[0128] After determining that the gas-sensitive material 75 has entered the adsorption saturation hysteresis state, the central control server 40 generates an actuation trigger command. The central control server 40 sends the actuation trigger command to the pump laser 20. The pump laser 20 receives the actuation trigger command and starts. The pump laser 20 outputs a high-energy pump beam. The center wavelength of the high-energy pump beam (such as the 980nm band) is outside the reflection band (such as the 1550nm band) of the gas actuation grating 73, so as to avoid optical crosstalk of the high-energy pump beam to the wavelength drift measurement.

[0129] A high-energy pump beam is transmitted through armored fiber 60 to the constant-volume cavity 74. The photothermal micro / nano coating 76 on the inner wall of the constant-volume cavity 74 absorbs the high-energy pump beam and converts the photon energy of the high-energy pump beam into heat. The heat is conducted to the gas-sensitive material 75, generating a local temperature increment on the surface and inside the gas-sensitive material 75. ;

[0130] Local temperature increment The computational relationship satisfies:

[0131]

[0132] In the formula, The photothermal conversion efficiency of the photothermal micro / nano coating is 76. The input power of the high-energy pump beam. The heat dissipation impedance inside the constant volume cavity 74;

[0133] Gas-sensitive material 75 in local temperature increment Under the influence of the temperature rise, the adsorption force between the gas-sensitive material 75 and the target gas molecules is weakened, and the gas-sensitive material 75 undergoes gas desorption, releasing the adsorbed target gas molecules. The released target gas molecules are discharged from the constant volume cavity 74. The central control server 40 has a preset deheating time. After the continuous operation time of the pump laser 20 reaches the deheating time, the central control server 40 generates a stop actuation command and sends the stop actuation command to the pump laser 20. The pump laser 20 stops outputting the high-energy pump beam, and the gas-sensitive material 75 completes active desorption.

[0134] Furthermore, the pump laser 20 stops outputting the high-energy pump beam, the heat inside the constant volume cavity 74 is dissipated to the external environment, the grating demodulator 30 continuously collects the real-time center wavelength data of the temperature compensation grating 71, and the grating demodulator 30 continuously transmits the real-time center wavelength data to the central control server 40.

[0135] The centralized control server 40 calculates the ambient temperature variable based on real-time center wavelength data. The central control server 40 has an internal temperature steady-state threshold. With steady-state determination time window The centralized control server 40 compares the ambient temperature variables. The absolute value and the steady-state temperature threshold When the ambient temperature changes The absolute value within the steady-state determination time window The temperature is continuously below the steady-state threshold. At that time, the central control server 40 determines that the internal temperature of the cross-modal physical actuation sensing probe 70 has returned to the initial environmental steady state;

[0136] After the internal temperature returns to its initial steady state, the gas-sensitive material 75 is in a contracted state without adsorption of target gas molecules. The gas-sensitive material 75 does not apply effective axial tensile stress to the gas-actuated grating 73. The central control server 40 controls the grating demodulator 30 to read the current real-time center wavelength of the gas-actuated grating 73, and the central control server 40 records the read real-time center wavelength as the calibration wavelength. calibrated wavelength This includes mechanical creep errors generated by the constant volume cavity 74 and the gas-actuated grating 73 in a long-term working environment;

[0137] The central control server 40 establishes a data communication connection with the underlying database 41, which stores the original center wavelength of the gas-actuated grating 73. The central control server 40 will calibrate the wavelength. Write the original initial center wavelength to the specified storage address of the underlying database 41. Replace with calibration wavelength The numerical update logic satisfies:

[0138]

[0139] In the formula, The updated initial center wavelength, The calibration wavelength after desorption and reset;

[0140] The central control server 40 completes the update operation of the reference zero-point parameter, and then calls the updated initial center wavelength from the underlying database 41. The central control server 40 utilizes the updated initial center wavelength. The center wavelength drift of the gas-actuated grating 73 is calculated in subsequent monitoring cycles. The central control server 40 eliminates the zero-point baseline drift error caused by mechanical creep and restores the real-time calculation status of the target gas concentration variable at the working face.

Claims

1. An integrated multi-sensor working face safety state real-time perception and alarm system, characterized in that, include: Broadband light source (10), pump laser (20), grating demodulator (30), centralized control server (40), optical coupler (50), armored fiber (60), cross-modal physical actuation sensing probe (70) and explosion-proof linkage control box (80); The output end of the broadband light source (10) and the output end of the pump laser (20) are respectively connected to the input end of the optical coupler (50). The output end of the optical coupler (50) is connected to the input end of the armored optical fiber (60). The receiving end of the grating demodulator (30) is connected to the armored optical fiber (60) through the optical coupler (50). The central control server (40) is connected to the grating demodulator (30) and the pump laser (20) through data cables. The central control server (40) is connected to the explosion-proof linkage control box (80) through industrial Ethernet. The explosion-proof linkage control box (80) is connected in series with the power supply circuit of the working face power equipment. Multiple cross-modal physical actuation sensing probes (70) are connected in series along the extension direction of the armored optical fiber (60) into the optical path of the armored optical fiber (60); The transmodal physical actuation sensing probe (70) includes a temperature compensation grating (71), a strain sensing grating (72), a gas actuation grating (73), and a constant volume cavity (74). The temperature compensation grating (71), the strain sensing grating (72), and the gas actuation grating (73) are cascaded sequentially along the core axis of the armored optical fiber (60) and have non-overlapping initial center wavelengths.

2. The integrated multi-sensor real-time sensing and alarm system for the safety status of a working face according to claim 1, characterized in that, In the physical cascade structure of the cross-modal physical actuation sensing probe (70): The temperature compensation grating (71) is encapsulated in a micro capillary tube. One end of the micro capillary tube is fixed to the inner wall of the housing of the transmodal physical actuation sensing probe (70), and the other end is suspended, so that the two ends of the fiber core of the temperature compensation grating (71) do not bear external axial stress and transverse shear force. The two ends of the strain sensing grating (72) are respectively fixed on two relative displacement nodes of the hydraulic support of the working face, and the fiber core axis of the strain sensing grating (72) is parallel to the direction of force deformation of the hydraulic support of the working face.

3. An integrated multi-sensor working face safety state real-time perception and alarm system according to claim 1, characterized in that, The gas-actuated grating (73) is disposed in a constant volume cavity (74), which is a rigid sealed shell structure with a fixed internal volume. The constant volume cavity (74) is filled with a gas-sensitive material (75), and the inner wall of the constant volume cavity (74) is deposited with a photothermal micro-nano coating (76). The constant volume cavity (74) is provided with a frictionless elastic diaphragm transmission assembly. One end of the gas sensitive material (75) abuts against the inner wall of the constant volume cavity (74), and the other end is in contact with the force-bearing surface of the elastic diaphragm transmission assembly. The center displacement node of the elastic diaphragm transmission assembly is connected to the end of the gas actuation grating (73). The central control server (40) controls the pump laser (20) to output pump light and transmit it to the constant volume cavity (74). The photothermal micro-nano coating (76) absorbs the pump light and generates heat. The heat is conducted to the surface of the gas-sensitive material (75) so that the gas-sensitive material (75) is heated and undergoes a gas desorption process.

4. An integrated multi-sensor working face safety state real-time perception and alarm system according to claim 3, characterized in that, The internal geometric constraints of the constant-volume cavity (74) convert the volume expansion of the gas-sensitive material (75) into the deflection displacement of the elastic diaphragm, and the axial tensile deformation of the gas-actuated grating (73) driven by the elastic diaphragm. satisfy: in, The initial volume of the gas-sensitive material (75) is given. The concentration volume expansion coefficient of the gas-sensitive material (75) is given. The coefficient of volumetric thermal expansion of the gas-sensitive material (75) is given. For the ambient temperature variable, For the target gas concentration variable, This is the effective cross-sectional area of ​​the elastic diaphragm under stress.

5. The integrated multi-sensor working face safety state real-time perception and alarm system according to claim 1, characterized in that, The central control server (40) is configured to acquire the center wavelength drift of each grating as resolved by the grating demodulator (30); The center wavelength drift, environmental variables, and sensitivity coefficient parameters are combined to construct a third-order forward sensing matrix equation for orthogonal decoupled calculation; the third-order forward sensing matrix equation satisfies: In the formula, , , The center wavelength shifts of the temperature compensation grating (71), strain sensing grating (72), and gas actuation grating (73) are respectively. , , These are the corresponding temperature sensitivity coefficients; , These are the corresponding strain sensitivity coefficients; This is the concentration-induced strain proportionality coefficient; For the ambient temperature variable, For structural strain variables, The target gas concentration variable.

6. An integrated multi-sensor working face safety state real-time perception and alarm system according to claim 5, characterized in that, The centralized control server (40) is configured to perform inverse matrix operations on the third-order forward sensing matrix equation to generate an inverse orthogonal decoupling model, and output environmental temperature variables, structural strain variables and target gas concentration variables; Furthermore, when the calculated structural strain variable exceeds the preset mechanical yield deformation threshold, or the target gas concentration variable exceeds the preset lower explosive limit concentration threshold, the centralized control server (40) is configured to generate an over-limit action command.

7. The integrated multi-sensor working face safety state real-time perception and alarm system according to claim 1, characterized in that, The explosion-proof linkage control box (80) constitutes a hard-wired linkage mechanism for passive sensing to active disconnection. It is equipped with a protocol parsing module (82), a relay drive circuit (83), an intermediate relay (84), a vacuum contactor (85), and an independent control power supply (86). The independent control power supply (86) is a mine-use intrinsically safe backup power supply with rated endurance capacity. It is independent of the main power supply circuit of the working face power equipment and continuously provides independent working voltage to the protocol parsing module (82) and the relay drive circuit (83) during a period of safe endurance after the main power supply circuit is cut off. The protocol parsing module (82) is used to receive and parse the over-limit action command issued by the centralized control server (40), and then output a trigger level to the relay drive circuit (83) to control the normally closed contact of the intermediate relay (84) to open, thereby triggering the vacuum contactor (85) to physically cut off the power supply circuit of the working face power equipment.

8. The integrated multi-sensor working face safety state real-time perception and alarm system according to claim 1, characterized in that, The centralized control server (40) is configured to synchronously perform time derivative calculations on the target gas concentration variable to obtain the target gas concentration change rate; When the rate of change of the target gas concentration is lower than the set hysteresis judgment threshold within the preset time window, and the absolute value of the target gas concentration variable is greater than zero, it is determined that the gas sensitive material (75) in the cross-modal physical actuation sensing probe (70) has entered the adsorption saturation state. A start-up level signal is sent to the pump laser (20) to output a high-energy pump beam to induce gas desorption in the gas-sensitive material (75).

9. An integrated multi-sensor working face safety state real-time perception and alarm system according to claim 8, characterized in that, The central control server (40) is also configured to: After the pump laser (20) stops outputting the high-energy pump beam, the ambient temperature variable calculated based on the real-time center wavelength data... When the absolute value of the temperature is continuously less than the steady-state threshold within the steady-state determination time window, the internal temperature is determined to have recovered to the initial environmental steady state. The current real-time center wavelength of the gas-actuated grating (73) is recorded as the calibration wavelength, and the original initial center wavelength in the underlying database is replaced with the calibration wavelength to complete the initial center wavelength update of the gas-actuated grating (73).

10. A method for real-time sensing and alarming of safety status of a working face based on the system according to any one of claims 1 to 9, characterized in that, Includes the following steps: Initialization calibration steps: In the initial state where there is no external stress on the working surface and no target gas infiltration, the broadband light source (10) outputs a sensing beam, and the grating demodulator (30) reads and records the initial center wavelength values ​​of the temperature compensation grating (71), strain sensing grating (72) and gas actuation grating (73), and stores the initial center wavelength values ​​in the central control server (40) as the reference data for wavelength drift calculation; Real-time monitoring stage: The broadband light source (10) continuously outputs a broadband sensing beam, which is injected into the armored fiber (60) via the optical coupler (50) and transmitted to multiple transmodal physical actuation sensing probes (70) connected in series; each grating performs wavelength selective reflection on the broadband sensing beam to form a narrowband reflected light signal, which is transmitted in reverse along the armored fiber (60) and enters the grating demodulator (30) via the optical coupler (50); the grating demodulator (30) extracts the real-time center wavelength data and sends it to the central control server (40) for analysis, calculation and instruction output.

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