Mining intrinsically safe digital monitoring device

Abstract

The invention relates to the field of coal mine underground safety monitoring, in particular to a mining intrinsically safe digital monitoring device. According to the scheme, the system comprises a dynamic energy control module, a multi-environment self-adaptive imaging module, a composite protection heat dissipation module and an intelligent power management module. The dynamic energy control module adopts a three-level protection framework, a current sensor is adopted for monitoring loop current in real time in first-level hardware current limiting, a thermistor is connected in parallel to compensate temperature drift, and microsecond-level response is achieved in cooperation with an MOS tube; the second-stage dynamic PID control is based on a PID control algorithm of the microcontroller, and the PWM duty ratio is adjusted in real time; the third-stage redundancy protection adopts a mode of parallel connection of electronic fusing and mechanical fusing; the multi-environment self-adaptive imaging module is integrated with a PM2.5 sensor and an illuminance sensor; a shell of the composite protection heat dissipation module is made of alloy made of ABS resin and polycarbonate, the intelligent power management module adopts a battery box handshake protocol, and the coal mine underground safety monitoring system is suitable for coal mine underground safety monitoring.

Description

Technical Field

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

[0002] The environment in underground coal mines is complex, with various safety hazards such as gas accumulation, coal dust explosion, roof collapse, and excessive carbon monoxide. In the early stage, miners relied on portable gas detectors (such as optical interference gas detectors) or CO detection tubes to record data regularly. The disadvantages are poor real-time performance and limited coverage, and continuous monitoring cannot be achieved. In the later stage, fixed sensors (such as catalytic combustion gas sensors) were connected through cables to transmit data to the ground monitoring center. The disadvantages are complex wiring, high cost, and it is difficult to cover underground mobile equipment (such as coal shearers).

[0003] With the development of wireless sensor networks and Internet of Things technologies, by deploying low-power ZigBee, LoRa, or Wi-Fi modules, wireless transmission of data such as gas and dust is realized. The advantages are flexible deployment in key areas such as working faces and return airways. However, it is still difficult to adapt to harsh environments and cannot meet the requirements of high temperature and humidity resistance and anti-dust interference.

[0004] The existing underground coal mine safety monitoring devices also have the following disadvantages: Insufficient energy control. The response time of the traditional current limiting circuit is >200 ms, which cannot meet the spark test requirements of GB3836.4-2010. There is a dead zone in single fuse protection, and the action threshold error of the fuse is large.

[0005] The imaging quality underground is low. Existing mine cameras are blurred when the dust concentration >10 mg / m³, and lack adaptive adjustment based on dust concentration.

[0006] Defects in structural design. The metal shell causes excessive weight, and it is difficult to balance heat dissipation and protection. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an intrinsically safe digital monitoring device for mines, which improves the energy control ability and imaging quality of the device.

[0008] The present invention adopts the following technical solutions to achieve the above purpose. The present invention provides an intrinsically safe digital monitoring device for mines, including: including a dynamic energy control module, a multi-environment adaptive imaging module, a composite protection and 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 real-time monitor the loop current, shunts a thermistor to compensate for temperature drift, and cooperates with a MOS tube to achieve microsecond-level response; The second-level dynamic PID (Proportional-Integral-Derivative Control) is based on the PID control algorithm of the microcontroller and adjusts the PWM (Pulse Width Modulation) duty cycle in real time; The third-level redundant protection adopts the method of parallel connection of electronic fusing and mechanical fusing; The multi-environment adaptive imaging module 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; The housing of the composite protection and heat dissipation module is made of an alloy of ABS resin and polycarbonate, the internal bracket is made of magnesium alloy, the sealing structure includes silicone rubber ring compression sealing, nano-hydrophobic coating and labyrinth drainage groove, and the heat dissipation design includes that the internal air duct adopts 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.

[0009] Furthermore, the formula for setting the current limiting threshold of the first-level hardware current limiting is: , represents the current limiting threshold, is the measured peak current, and is the maximum value of the set loop current limit.

[0010] Furthermore, the method for adjusting the PWM duty cycle in real time is: ; In the formula, represents the proportional gain, represents the integral gain, represents the derivative gain, represents the difference between the set current and the actual current, represents the temperature compensation coefficient, represents the ambient temperature, represents the total output of PID control, represents the time constant; The total energy accumulation model is: ; In the formula, represents the actual current of the loop, is the resistance when the IRF7319 MOSFET is turned on, represents the input equivalent capacitance, represents the input voltage, and T represents the upper limit of the time for total energy accumulation.

[0011] Furthermore, the preprocessing of the raw image in RAW format is as follows: ; ; In the formula, represents the dark current compensation matrix, represents the camera microlens correction factor, G represents the environmental gain coefficient, represents the dust concentration, represents the environmental temperature, represents the original input image, represents the output image after preprocessing; The dynamic noise reduction is the adaptive adjustment of the bilateral filtering parameters based on the dust concentration, and the method is as follows: ; ; In the formula, represents the standard deviation in the spatial domain, represents the standard deviation in the value domain.

[0012] Furthermore, the intelligent power management module adopts dual power path management. The main path uses the LTC4417 ideal diode controller, and the backup path uses the TPS22965 load switch.

[0013] The beneficial effects of the present invention are as follows: 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, and a parallel thermistor compensates for the temperature drift. Together with the MOS transistor, it realizes a microsecond-level 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 adopts the method of parallel connection of electronic fusing and mechanical fusing, which greatly improves the energy control ability.

[0014] 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. The image preprocessing takes into account the dust concentration and environmental temperature, and also considers parameters such as the dark current compensation matrix and the camera microlens correction factor. The dynamic noise reduction includes the method of adaptive adjustment of the bilateral filtering parameters based on the dust concentration, which improves the imaging quality of the monitoring device underground in the mine.

[0015] The composite protection and heat dissipation module of the present invention is made of an alloy of ABS resin and polycarbonate, the internal bracket is made of magnesium alloy, the sealing structure includes silicone ring compression sealing, nano-hydrophobic coating and labyrinth drainage grooves, and the heat dissipation design includes a biomimetic fin structure for the internal air duct, which reduces the weight and takes into account heat dissipation and protection. Description of the Drawings

[0016] Figure 1 It is a structural block diagram of a mine intrinsically safe digital monitoring device provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of the battery box communication protocol timing provided by an embodiment of the present invention. Detailed Embodiments

[0017] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, 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.

[0018] The present invention provides a mine intrinsically safe digital monitoring device, as Figure 1 shown, including a dynamic energy control module, a multi-environment adaptive imaging module, a composite protection and heat dissipation module, and an intelligent power management module.

[0019] Dynamic energy control module: Adopts a three-level protection architecture; The first level (hardware current limiting) Adopts a TI INA240 current sensor (bandwidth 1MHz) to monitor the loop current of the entire device in real time, and a parallel NTC thermistor (MF52-103) compensates for the temperature drift, and cooperates with an IRF7319 MOSFET (Rds(on)=5mΩ) to achieve a microsecond-level response.

[0020] Current limiting threshold setting formula: , is the measured current peak value, and is the maximum value of the set loop current limit; The second level (software dynamic PID control) Based on the PID control algorithm of STM32F407, the PWM duty cycle is adjusted in real time.

[0021] ; In the formula, represents the proportional gain, represents the integral gain, represents the derivative gain, represents the difference between the set current and the actual current, represents the temperature compensation coefficient, represents the ambient temperature, Represents the total output of PID control, Represents the time constant, a parameter = 0.8, = 0.05, = 0.1, obtained through the particle swarm optimization algorithm.

[0022] The total energy accumulation model is: ; In the formula, Represents the actual current of the circuit, Is the on-resistance of the IRF7319 MOSFET, Represents the input equivalent capacitance, Represents the input voltage, and T represents the upper limit of the time for total energy accumulation; The third stage (redundant protection) Electronic fusing (response time < 10 μs) is in parallel with mechanical fusing (1.8 A ± 2%) to ensure safety under extreme faults.

[0023] The maximum fault current in the short-circuit experiment is 1.53 A (passing the test of item 10.1 of GB3836.4-2010); Calculated value of energy release: 0.5 × 297 μF × (8.6 V) 2 + 0.5 × 89.5 μH × (1.5 A) 2 = 11.3 mJ < 20 mJ (safety threshold). Represents the equivalent inductance in the circuit.

[0024] Multi-environment adaptive imaging module: Sensor fusion: Integrates a PM2.5 sensor (Sharp GP2Y1010AU0F, detection range 0~1000 μg / m³) and an illuminance sensor (VEML7700, range 0~120 klux).

[0025] The image processing process includes image preprocessing and dynamic noise reduction; Preprocessing of the RAW format raw image is as follows: ; ; In the formula, 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, Represents the dust concentration, Represents the environmental temperature, represents the original input image, represents the output image after preprocessing; Dynamic noise reduction is the adaptive adjustment of bilateral filtering parameters based on dust concentration, and the method is as follows: ; ; In the formula, represents the standard deviation in the spatial domain, represents the standard deviation in the value domain.

[0026] When the dust concentration is 50mg / m³, MTF50 > 0.3 (ISO12233 test chart); The signal-to-noise ratio is increased to 35dB in a low-light (1lux) environment (only 28dB for traditional algorithms).

[0027] Composite protection and heat dissipation module: Material selection: For the outer shell, ABS+PC alloy, an alloy made of ABS resin and polycarbonate (UL94 V-0 flame retardant rating, surface insulation resistance ≤ 1GΩ); for the internal bracket, magnesium-aluminum alloy (thickness 1.2mm, density 1.8g / cm³).

[0028] Sealing structure: Triple protection design, compression sealing with silicone rubber ring (compression rate 25% ± 3%, Shore hardness 60 ± 5); Nanometer hydrophobic coating (thickness 50μm, contact angle > 150°); labyrinth drainage groove (groove depth 0.8mm, spacing 2mm, inclination angle 5°).

[0029] Heat dissipation design: The internal air duct adopts a bionic fin structure (fin height 3mm, spacing 1.5mm); heat conduction path, image sensor → copper substrate → magnesium-aluminum bracket → outer shell.

[0030] The total weight of the whole machine is 720g (40% lighter than similar products); The dust intrusion amount is 0.3g / m³ in the GB / T4208-2017 test (IP54 requirement ≤ 1g / m³); The surface temperature ≤ 82℃ under the high-temperature test (60℃) (GB3836.1-2010 requirement ≤ 150℃).

[0031] Intelligent power management module: The battery box handshake protocol is as Figure 2 shown. When powering 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 according to the returned data. Dual power path management: Main path: LTC4417 ideal diode controller (on-resistance 18mΩ); Backup path: TPS22965 load switch (switching time < 1ms).

[0032] Power supply switching interruption time < 0.5ms (MT210-1990 requires < 1ms); Battery box over-temperature protection accuracy ±1.5°C (traditional solution ±3°C).

[0033] The dynamic energy control circuit is implemented as follows: Component selection: Main control chip, STM32F407VGT6 (168MHz, with FPU), current sensor, INA240A1PW (common-mode voltage -4~80V); MOSFET, IRF7319 (Vds = 30V, Rds(on) = 18mΩ).

[0034] PCB layout specification: The distance between the power layer and the signal layer ≥ 0.8mm (meeting the creepage distance requirements of GB3836.4); The length matching error of key signal lines < 5mm (reducing EMI interference).

[0035] Test data: Short-circuit response time, 8.2μs (measured by Tektronix MSO54 oscilloscope); Steady-state current fluctuation: ±0.02A (MT209-1990 requires ±0.05A).

[0036] Adaptive imaging debugging: Parameter calibration: Calibrate the PM2.5 sensor in a standard dust chamber, fitting formula: , where Vout represents the output voltage of the sensor.

[0037] Algorithm deployment: Implement real-time processing in an embedded Linux system (kernel 4.19), frame rate ≥ 25fps.

[0038] Imaging test: Using an ISO12233 test chart, MTF50 = 0.32 was measured in a 50mg / m³ dust environment (the traditional algorithm was only 0.25).

[0039] The above are only the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications, and environments, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in related fields. And the changes and modifications made by those skilled in the art that do not depart from the spirit and scope of the present invention should all be within the protection scope of the appended claims of the present invention.

Claims

1. A intrinsically safe digital monitoring device for mine use, characterized in that, 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; 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, shunts a thermistor to compensate for temperature drift, and cooperates with MOS transistors to achieve microsecond-level response; The second level is based on the PID control algorithm of the microcontroller to adjust the PWM duty cycle in real time; The third level uses a redundant protection method by paralleling an electronic fuse and a mechanical fuse; The multi-environment adaptive imaging module 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; The housing of the composite protection and heat dissipation module is made of an alloy of ABS resin and polycarbonate, the internal bracket is made of magnesium alloy, the sealing structure includes silicone rubber ring compression sealing, nano-hydrophobic coating, and labyrinth drainage grooves, and the heat dissipation design includes that the internal air duct adopts a bionic fin structure; The intelligent power management module adopts a 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.

2. The intrinsically safe digital monitoring device for mines according to claim 1, characterized in that, The formula for setting the current limiting threshold of the first-level hardware current limiting is: , represents the current limiting threshold value, is the measured peak current and is the maximum value set for the loop current limit.

3. The intrinsically safe digital monitoring device for mines according to claim 1, characterized in that, The way to adjust the PWM duty cycle in real time is as follows: ; Wherein, represents the proportional gain, represents the integral gain, represents the derivative gain, represents the difference between the set current and the actual current, represents the temperature compensation coefficient, represents the ambient temperature, represents the total output of the PID control, represents the time constant; The total energy accumulation model is: ； Wherein, represents the actual current of the circuit, is the resistance when the MOSFET is turned on, represents the input equivalent capacitance, represents the input voltage, represents the total energy, and T represents the upper limit of the time for total energy accumulation.

4. The intrinsically safe digital monitoring device for mines according to claim 1, wherein, The preprocessing of the RAW format original image is as follows: ； ； In the formula, represents the dark current compensation matrix, represents the camera microlens correction factor, G represents the environmental gain coefficient, represents the dust concentration, represents the environmental temperature, represents the original input image, represents the preprocessed output image; The dynamic noise reduction is the adaptive adjustment of bilateral filtering parameters based on the dust concentration, and the method is as follows: ； ； In the formula, represents the standard deviation in the spatial domain, represents the standard deviation in the value domain.

5. The intrinsically safe digital monitoring device for mines according to claim 1, wherein The intelligent power management module adopts dual power path management. The main path uses an LTC4417 ideal diode controller, and the standby path uses a TPS22965 load switch.

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