A digital monitoring device for intrinsic safety in mines

Abstract

The present invention relates to the field of underground coal mine safety monitoring, and specifically to an intrinsically safe digital monitoring device for mines. The solution includes a dynamic energy control module, a multi-environment adaptive imaging module, a composite protective heat dissipation module, and an intelligent power management module. The dynamic energy control module adopts a three-level protection architecture. The first-level hardware current limiting uses a current sensor to monitor the loop current in real time, a parallel thermistor to compensate for temperature drift, and cooperates with a MOS tube to achieve microsecond response. The second-level dynamic PID control is based on a microcontroller's PID control algorithm, adjusting the PWM duty cycle in real time. The third-level redundant protection adopts an electronic fuse in parallel with a mechanical fuse. The multi-environment adaptive imaging module integrates a PM2.5 sensor and an illumination sensor. The housing of the composite protective heat dissipation module is made of an alloy of ABS resin and polycarbonate, and the intelligent power management module adopts a battery box handshake protocol. The present invention is suitable for underground coal mine safety monitoring.

Description

Technical Field

[0001] The present invention relates to the field of underground coal mine safety monitoring, and in particular to an intrinsically safe digital monitoring device for mines. Background Art

[0002] The complex underground environment of coal mines presents numerous safety hazards, including gas accumulation, coal dust explosions, roof collapse, and excessive carbon monoxide levels. Early systems relied on miners carrying portable gas detectors (such as optical interferometer gas detectors) or CO detection tubes to regularly record data. These systems suffered from poor real-time performance, limited coverage, and the inability to continuously monitor the mine's atmosphere. Later, fixed sensors (such as catalytic combustion gas sensors) were connected via cables to transmit data to surface monitoring centers. However, these systems faced challenges, including complex wiring, high costs, and difficulty covering mobile underground equipment (such as shearers).

[0003] With the development of wireless sensor networks and the Internet of Things (IoT), wireless backhaul of data on gas and dust levels can be achieved by deploying low-power ZigBee, LoRa, or Wi-Fi modules. These systems offer advantages such as flexible deployment in key areas like the mining face and return air lanes. However, they still struggle to adapt to harsh environments and cannot meet requirements for high temperature, high humidity, and dust resistance.

[0004] The existing coal mine underground safety monitoring device also has the following shortcomings:

[0005] Energy control is insufficient, and the response time of traditional current-limiting circuits is greater than 200ms, failing to meet the spark test requirements of GB3836.4-2010. Single fuse protection has a dead zone, and the fuse action threshold error is large.

[0006] The imaging quality in mines is poor. Existing mining cameras produce blurred images when the dust concentration is greater than 10mg / m³, and lack adaptive adjustment based on dust concentration.

[0007] Structural design defects and the metal casing make it too heavy, making it difficult to balance heat dissipation and protection. Summary of the Invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an intrinsically safe digital monitoring device for mining, thereby improving the energy control capability and imaging quality of the device.

[0009] The present invention adopts the following technical solutions to achieve the above-mentioned purpose. The present invention provides an intrinsically safe digital monitoring device for mining, comprising:

[0010] It includes dynamic energy control module, multi-environment adaptive imaging module, composite protection and heat dissipation module and intelligent power management module;

[0011] The dynamic energy control module adopts a three-level protection architecture. The first level hardware current limiting uses a current sensor to monitor the loop current in real time, a parallel thermistor to compensate for temperature drift, and a MOS tube to achieve microsecond response.

[0012] The second-level dynamic PID (Proportional-Integral-Derivative Control) uses a microcontroller-based PID control algorithm to adjust the PWM (Pulse Width Modulation) duty cycle in real time.

[0013] The third level of redundant protection uses electronic fusing and mechanical fusing in parallel;

[0014] The multi-environment adaptive imaging module integrates a PM2.5 sensor and an illumination sensor. The image processing process of the multi-environment adaptive imaging module includes image preprocessing and dynamic noise reduction;

[0015] The composite protective heat dissipation module has an outer shell made of an alloy of ABS resin and polycarbonate, an internal bracket made of magnesium-aluminum alloy, a sealing structure including a silicone ring compression seal, a nano-hydrophobic coating, and a labyrinth-style drainage groove, and a heat dissipation design including an internal air duct with a bionic fin structure.

[0016] The intelligent power management module adopts the battery box handshake protocol. When powered on, the host sends a handshake signal, and the battery box returns a message containing voltage and temperature data. The host dynamically adjusts the power strategy according to the returned data.

[0017] Furthermore, the current limiting threshold setting formula of the first-level hardware current limiting is:

[0018] , Indicates the current limiting threshold, is the measured current peak value, which is the maximum value of the set loop current limit.

[0019] Furthermore, the way to adjust the PWM duty cycle in real time is: ;

[0020] Where, represents the proportional gain, represents the integral gain, represents the differential gain, Indicates the difference between the set current and the actual current. represents the temperature compensation coefficient, Indicates the ambient temperature, Indicates the total output of PID control, represents the time constant;

[0021] The total energy accumulation model is:

[0022] ;

[0023] Where, Indicates the actual current of the circuit. is the resistance of the IRF7319 MOSFET when it is on, represents the input equivalent capacitance, represents the input voltage, and T represents the upper limit of the time for total energy accumulation.

[0024] Furthermore, the original image in RAW format is preprocessed as follows:

[0025] ;

[0026] ;

[0027] Where, represents the dark current compensation matrix, represents the camera microlens correction factor, G represents the environmental gain coefficient, Indicates dust concentration, Indicates the ambient temperature, represents the original input image, represents the output image after preprocessing;

[0028] The dynamic noise reduction is based on the adaptive adjustment of the bilateral filter parameters of the dust concentration, as follows:

[0029] ;

[0030] ;

[0031] Where, represents the spatial domain standard deviation, Indicates the standard deviation of the range.

[0032] Furthermore, the intelligent power management module adopts dual power path management, the main path adopts the LTC4417 ideal diode controller, and the backup path adopts the TPS22965 load switch.

[0033] The beneficial effects of the present invention are:

[0034] The dynamic energy control module of the present invention adopts a three-level protection architecture. The first-level hardware current limiting uses a current sensor to monitor the loop current in real time, a parallel thermistor to compensate for temperature drift, and cooperates with the MOS tube to achieve microsecond response. The second-level dynamic PID control is based on the PID control algorithm of the microcontroller to adjust the PWM duty cycle in real time. The third-level redundant protection uses electronic fusing and mechanical fusing in parallel, which greatly improves the energy control capability.

[0035] The multi-environment adaptive imaging module of the present invention integrates a PM2.5 sensor and an illuminance sensor. The image processing process of the multi-environment adaptive imaging module includes image preprocessing and dynamic noise reduction. Image preprocessing takes into account dust concentration and ambient temperature, as well as parameters such as the dark current compensation matrix and the camera microlens correction factor. Dynamic noise reduction includes a method of adaptively adjusting bilateral filtering parameters based on dust concentration, thereby improving the imaging quality of the monitoring device in mines.

[0036] The composite protective heat dissipation module of the present invention adopts an alloy made of ABS resin and polycarbonate, the internal bracket is made of magnesium-aluminum alloy, the sealing structure includes a silicone ring compression seal, a nano-hydrophobic coating and a maze-type drainage groove, and the heat dissipation design includes an internal air duct with a bionic fin structure, which reduces weight and takes into account both heat dissipation and protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a structural block diagram of a digital monitoring device for intrinsically safe mining provided by an embodiment of the present invention;

[0038] Figure 2 This is a timing diagram of the battery box communication protocol provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0040] The present invention provides a digital monitoring device for intrinsically safe mining. Figure 1 As shown, it includes a dynamic energy control module, a multi-environment adaptive imaging module, a composite protection and heat dissipation module, and an intelligent power management module.

[0041] Dynamic Energy Control Module:

[0042] Adopting a three-level protection architecture;

[0043] Level 1 (hardware current limiting)

[0044] A TI INA240 current sensor (bandwidth 1MHz) is used to monitor the loop current of the entire device in real time. An NTC thermistor (MF52-103) is connected in parallel to compensate for temperature drift, and an IRF7319 MOSFET (Rds(on) = 5mΩ) is used to achieve microsecond response.

[0045] Current limiting threshold setting formula:

[0046] , is the measured current peak value, which is the maximum value of the set loop current limit;

[0047] Second level (software dynamic PID control)

[0048] Based on the PID control algorithm of STM32F407, the PWM duty cycle is adjusted in real time.

[0049] ;

[0050] Where, represents the proportional gain, represents the integral gain, represents the differential gain, Indicates the difference between the set current and the actual current. represents the temperature compensation coefficient, Indicates the ambient temperature, Indicates the total output of PID control, Represents the time constant, parameter =0.8, =0.05, =0.1, obtained by particle swarm optimization algorithm.

[0051] The total energy accumulation model is:

[0052] ;

[0053] Where, Indicates the actual current of the circuit. is the resistance of the IRF7319 MOSFET when it is on, represents the input equivalent capacitance, represents the input voltage, T represents the upper limit of the time for total energy accumulation;

[0054] Level 3 (redundant protection)

[0055] Electronic fusing (response time <10μs) is connected in parallel with mechanical fusing (1.8A±2%) to ensure safety under extreme fault conditions.

[0056] The maximum fault current in the short-circuit test is 1.53A (GB3836.4-2010 10.1 test passed);

[0057] Calculated energy release: 0.5×297μF×(8.6V) 2 +0.5×89.5μH×(1.5A) 2 =11.3mJ<20mJ (safety threshold). Represents the equivalent inductance in the loop.

[0058] Multi-environment adaptive imaging module:

[0059] Sensor fusion: Integrates a PM2.5 sensor (Sharp GP2Y1010AU0F, detection range 0-1000 μg / m³) and an illuminance sensor (VEML7700, range 0-120 klux).

[0060] The image processing process includes image preprocessing and dynamic noise reduction;

[0061] The original image preprocessing in RAW format is as follows:

[0062] ;

[0063] ;

[0064] Where, Represents the dark current compensation matrix (calibration data is stored in FLASH), Represents the camera microlens correction factor (generated by factory calibration), G represents the environmental gain coefficient, Indicates dust concentration, Indicates the ambient temperature, represents the original input image, represents the output image after preprocessing;

[0065] Dynamic noise reduction is based on the adaptive adjustment of bilateral filter parameters based on dust concentration, as follows:

[0066] ;

[0067] ;

[0068] Where, represents the spatial domain standard deviation, Indicates the standard deviation of the range.

[0069] MTF50>0.3 when dust concentration is 50mg / m³ (ISO12233 test card);

[0070] The signal-to-noise ratio in low-light (1lux) environments is improved to 35dB (the traditional algorithm is only 28dB).

[0071] Composite protective heat dissipation module:

[0072] Material selection: Shell, ABS+PC alloy, that is, an alloy made of ABS resin and polycarbonate (UL94 V-0 flame retardant rating, surface insulation resistance ≤1GΩ); internal bracket, magnesium-aluminum alloy (thickness 1.2mm, density 1.8g / cm³).

[0073] Sealing structure: triple protection design, silicone ring compression seal (compression rate 25%±3%, Shore hardness 60±5);

[0074] Nano-hydrophobic coating (thickness 50 μm, contact angle > 150°); maze-type drainage groove (groove depth 0.8 mm, spacing 2 mm, inclination angle 5°).

[0075] Heat dissipation design: The internal air duct adopts a bionic fin structure (fin height 3mm, spacing 1.5mm); the heat conduction path is image sensor → copper substrate → magnesium-aluminum bracket → housing.

[0076] The whole machine weighs 720g (40% lighter than similar products);

[0077] Dust intrusion in the GB / T4208-2017 test is 0.3g / m³ (IP54 requires ≤1g / m³);

[0078] During the high temperature test (60°C), the lower surface temperature is ≤82°C (GB3836.1-2010 requires ≤150°C).

[0079] Intelligent power management module:

[0080] Battery box handshake protocol such as Figure 2 As shown in the figure, when powered on, the host sends a 0x55AA handshake signal; the battery box returns a 16-byte message containing voltage and temperature data; the host dynamically adjusts the power strategy based on the returned data. Dual power path management:

[0081] Primary path: LTC4417 ideal diode controller (on-resistance 18mΩ); backup path: TPS22965 load switch (switching time <1ms).

[0082] Power switching interruption time <0.5ms (MT210-1990 requires <1ms);

[0083] The battery box over-temperature protection accuracy is ±1.5°C (traditional solution ±3°C).

[0084] The dynamic energy control circuit is implemented as follows:

[0085] Component selection: Main control chip, STM32F407VGT6 (168MHz, with FPU), current sensor, INA240A1PW (common mode voltage -4~80V); MOSFET, IRF7319 (Vds=30V, Rds(on)=18mΩ).

[0086] PCB layout specifications: The distance between the power layer and the signal layer is ≥ 0.8mm (meeting the creepage distance requirements of GB3836.4);

[0087] The length matching error of key signal lines is less than 5mm (reducing EMI interference).

[0088] Test data: Short-circuit response time, 8.2μs (measured by Tektronix MSO54 oscilloscope); steady-state current fluctuation: ±0.02A (MT209-1990 requires ±0.05A).

[0089] Adaptive imaging debugging:

[0090] Parameter calibration: Calibrate the PM2.5 sensor in a standard dust chamber, fitting formula:

[0091] , Vout represents the output voltage of the sensor.

[0092] Algorithm deployment: Real-time processing is implemented in an embedded Linux system (kernel 4.19), with a frame rate ≥ 25fps.

[0093] Imaging test: Using the ISO12233 test chart in a 50mg / m³ dust environment, MTF50 was measured to be 0.32 (compared to 0.25 using the traditional method).

[0094] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A digital monitoring device for intrinsically safe mining, characterized in that: It includes dynamic energy control module, multi-environment adaptive imaging module, composite protection and heat dissipation module and intelligent power management module; The dynamic energy control module adopts a three-level protection architecture. The first level hardware current limiting uses a current sensor to monitor the loop current in real time, a parallel thermistor to compensate for temperature drift, and a MOS tube to achieve microsecond response. The current limiting threshold setting formula of the first level hardware current limiting is: , Indicates the current limiting threshold, is the measured current peak value, which is the maximum value of the set loop current limit; The second level is based on the microcontroller's PID control algorithm to adjust the PWM duty cycle in real time; The way to adjust the PWM duty cycle in real time is: ； Where, represents the proportional gain, represents the integral gain, represents the differential gain, Indicates the difference between the set current and the actual current. represents the temperature compensation coefficient, Indicates the ambient temperature, Indicates the total output of PID control, represents the time constant; The total energy accumulation model is: ； Where, Indicates the actual current of the circuit. is the resistance of the MOSFET when it is on, represents the input equivalent capacitance, Indicates the input voltage, represents the total energy, and T represents the upper limit of the time for total energy accumulation; The third level uses electronic fusing and mechanical fusing in parallel for redundant protection; The multi-environment adaptive imaging module integrates a PM2.5 sensor and an illumination sensor. The image processing process of the multi-environment adaptive imaging module includes image preprocessing and dynamic noise reduction; The original image preprocessing in RAW format is as follows: ； Where, represents the dark current compensation matrix, represents the camera microlens correction factor, G represents the environmental gain coefficient, Indicates dust concentration, Indicates the ambient temperature, represents the original input image, represents the output image after preprocessing; The dynamic noise reduction is based on the adaptive adjustment of the bilateral filter parameters of the dust concentration, as follows: ； ； Where, represents the spatial domain standard deviation, Indicates the standard deviation of the range; The composite protective heat dissipation module has an outer shell made of an alloy of ABS resin and polycarbonate, an internal bracket made of magnesium-aluminum alloy, a sealing structure including a silicone ring compression seal, a nano-hydrophobic coating, and a labyrinth-style drainage groove, and a heat dissipation design including an internal air duct with a bionic fin structure. The intelligent power management module adopts the battery box handshake protocol. When powered on, the host sends a handshake signal, and the battery box returns a message containing voltage and temperature data. The host dynamically adjusts the power strategy according to the returned data. The intelligent power management module adopts dual power path management, the main path adopts the LTC4417 ideal diode controller, and the backup path adopts the TPS22965 load switch.

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