Mine wind speed sensor compensation method and early warning mechanism adaptive to different degrees of dirt

Abstract

The present application relates to the technical field of coal mine ventilation detection, and specifically discloses a mine-used wind speed sensor compensation method and early warning mechanism suitable for different levels of dirt, to solve the problem that the prior art cannot dynamically compensate and grade early warn according to the level of dirt on the transducer. The reference voltage and the current voltage are respectively obtained under the cleaning and running state of the transducer, the level of dirt is quantified according to the two, and the voltage attenuation is calculated. The thickness of the attached layer is inverted through the voltage attenuation, and then the initial spacing of the transducer is dynamically corrected to obtain the actual effective spacing. The mine-used wind speed after compensation is calculated by substituting the corrected actual effective spacing into the time difference method formula. At the same time, the remaining available time is predicted according to the voltage drop rate, and the grading early warning threshold is set, and when the percentage of dirt reaches the corresponding threshold, a maintenance prompt or an alarm is output. The present application is mainly used for maintaining the precision of ultrasonic wind speed measurement and intelligently operating and maintaining in the harsh environment of a mine.

Description

Technical Field

[0001] This invention relates to the technical field of coal mine ventilation detection, and in particular to a compensation method and early warning mechanism for a mine wind speed sensor that adapts to different levels of dirt. Background Technology

[0002] Mining ultrasonic anemometers primarily rely on the time-of-flight method, calculating wind speed by measuring the time difference between the propagation of ultrasonic waves upstream and downstream. However, the harsh environment in mines, with its humidity and dust, leads to contamination of the ultrasonic transducer surface, altering the emission and reception intensity of sound waves and directly impacting measurement accuracy. Existing research focuses on temperature compensation, turbulence correction, shadowing effect compensation, or signal noise reduction, which, while improving measurement accuracy to some extent, fail to systematically address the problem of output signal attenuation caused by varying degrees of contamination. Especially when contamination is severe, signal strength may plummet or even disappear, and current technologies lack quantitative assessment, tiered early warning, and adaptive compensation mechanisms for different levels of contamination.

[0003] Currently, error compensation schemes for ultrasonic anemometers used in mines mainly include: real-time temperature compensation based on temperature sensors, turbulence model correction based on fluid dynamics, shadowing effect compensation models based on machine learning, and multi-channel cross-sectional average wind speed measurement. In addition, some studies have reduced signal noise by optimizing filtering algorithms. However, all of the above schemes have significant shortcomings: first, they all assume that the ultrasonic transducer is clean, failing to consider the dynamic attenuation effect of dirt on signal strength; second, they cannot provide differentiated processing strategies based on the degree of dirtiness, failing to provide effective wind speed compensation for light dirtiness and failing to issue clear maintenance warnings for heavy dirtiness. Therefore, existing technologies are insufficient to meet the actual engineering needs of complex mining environments. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] To address this issue, this invention proposes a compensation method and early warning mechanism for ultrasonic wind speed sensors used in mines that adapts to different levels of contamination. The aim is to solve the problem that existing technologies cannot dynamically compensate and provide graded early warnings based on the degree of contamination on the transducer surface, thereby achieving accurate wind speed measurement and intelligent operation and maintenance in complex mine environments.

[0006] According to an embodiment of the present invention, a compensation method for a mine wind speed sensor adaptable to different degrees of dirtiness is provided. The sensor includes a first ultrasonic transducer and a second ultrasonic transducer installed opposite to each other. The method includes the following steps: acquiring the reference voltage of the received signal when each transducer is used as a receiving end, with the transducers in a clean state. During sensor operation, the current received voltage of the received signal when each transducer acts as a receiver is acquired in real time. Based on reference voltage and current received voltage Quantify the degree of contamination on the surface of each transducer; utilize the current received voltage relative to reference voltage Attenuation Calculate the thickness of the surface deposits on the transducer caused by dirt adhesion. Based on the thickness of the adhesion layer The initial spacing of the transducers in a clean state Dynamic correction is performed to obtain the actual effective spacing. ; Measuring the downwind propagation time of ultrasonic waves and headwind propagation time And using the corrected actual effective spacing Calculate the compensated underground wind speed .

[0007] According to one embodiment of the present invention, using the current received voltage relative to reference voltage Attenuation Calculate the thickness of the adhesion layer The specific steps are as follows: using a pre-calibrated scaling factor Calculate the thickness of the adhesion layer proportionality coefficient Voltage attenuation was calibrated experimentally. With the thickness of the adhesion layer The correspondence was obtained.

[0008] According to one embodiment of the present invention, the scaling factor The calibration method is as follows: In a laboratory environment, simulated contaminant materials of different thicknesses are coated on the transducer surface. The change in received voltage and the actual thickness of the simulated contaminant material are measured simultaneously. The voltage attenuation is determined through linear regression analysis. The proportionality coefficient between thickness and other factors .

[0009] According to one embodiment of the present invention, the compensated underground wind speed The calculation formula is: .

[0010] According to one embodiment of the present invention, the degree of contamination on the surface of each transducer is quantified specifically by: based on a reference voltage. Current received voltage and the preset minimum measurable voltage threshold Define the percentage of dirt. .

[0011] According to one embodiment of the present invention, a warning step is further included: real-time recording of the current received voltage. Calculate the rate of voltage decrease over time using the corresponding timestamps. Based on the current received voltage Minimum measurable voltage threshold and voltage drop rate Predict remaining available time Based on the degree of soiling or remaining available time It generates and outputs corresponding maintenance prompts.

[0012] According to one embodiment of the present invention, maintenance prompts are generated and output based on the degree of dirtiness, specifically by setting at least one warning threshold; when the percentage of dirtiness... When the warning threshold is reached, a corresponding tiered warning message will be issued.

[0013] According to one embodiment of the present invention, the rate of voltage decrease over time is calculated. The specific steps are: store the most recent The voltage samples and their corresponding timestamps are linearly fitted using either the moving average method or the least squares method. The slope of the fitted line is then used as the current voltage rate of decrease. .

[0014] According to one embodiment of the present invention, the graded early warning prompt includes: when the percentage of dirt... When the first-level warning threshold is reached, a prompt message representing the first-level maintenance requirement is generated and output, while the compensated underground wind speed value continues to be output; when the percentage of dirt... Reaching the Level 2 warning threshold or the current received voltage Below the minimum measurable voltage threshold At that time, a serious alarm was triggered, and the mine's underground wind speed stopped after compensation. Output or output invalid flag.

[0015] This invention also provides a mine wind speed sensor early warning mechanism adaptable to different levels of contamination, including a state quantization module, a trend prediction module, and a graded early warning module; the state quantization module is used to determine the current received voltage of the transducer's received signal. With reference voltage The percentage of dirt, which represents the degree of dirtiness, is quantified. The trend prediction module is used to calculate the voltage drop rate based on historical voltage data. And combined with the current received voltage With the lowest measurable voltage threshold Predict remaining available time The graded early warning module is used to determine the percentage of dirt or grime. and / or remaining available time It compares the value with a preset threshold and triggers different levels of maintenance or alarm prompts.

[0016] The beneficial effects of this invention are: 1. Dynamic Spacing Correction for Guaranteed Measurement Accuracy: By real-time monitoring of the received voltage attenuation and quantifying the thickness of the dirt layer on the transducer surface, the effective spacing of the transducers caused by dirt is dynamically corrected and directly substituted into the time-of-flight calculation formula. This physical layer compensation method effectively eliminates the interference of dirt on the wind speed measurement benchmark, ensuring that the sensor maintains high-precision output even in light to moderately dirty environments, overcoming the inherent defect of traditional methods that ignore spacing changes.

[0017] 2. Intelligent predictive maintenance improves operational efficiency: Based on the rate of voltage drop of ultrasonic voltage signals, the system calculates the rate of dust accumulation in the environment and combines this with the current level of dirt to predict the remaining usable time in real time, dynamically outputting suggested maintenance prompts. This mechanism transforms passive maintenance into proactive planning, avoiding measurement interruptions due to sudden failures, significantly reducing the downtime risk of the mine ventilation monitoring system, and optimizing the allocation of manpower and resources.

[0018] 3. Graded early warning mechanism to enhance environmental adaptability: By setting a threshold for the percentage of dirt, graded early warning prompts can be achieved. This strategy can not only continuously provide compensated wind speed within the measurable range, but also provide clear warnings in the case of extreme dirt, thereby improving the reliability and intelligence level of the sensor in harsh mining environments. Attached Figure Description

[0019] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0021] This invention addresses two key issues caused by transducer contamination: first, contamination can alter the effective spacing between transducers, affecting the accuracy of wind speed measurements; second, existing technologies lack a quantitative assessment mechanism based on contamination levels, failing to provide measurement compensation for mild contamination or issue maintenance warnings for severe contamination, thus hindering the engineering needs of complex mining environments. To address these issues, this invention quantifies the degree of contamination on the transducer surface by real-time monitoring of ultrasonic signal intensity attenuation characteristics, dynamically adjusting the effective spacing parameters accordingly to achieve accurate wind speed measurement compensation. Simultaneously, it establishes a correlation model between contamination levels and measurement errors, predicting and recommending maintenance times based on the current contamination environment, and triggering warnings when severe contamination renders measurement impossible.

[0022] This invention provides a compensation method and early warning mechanism for mine wind speed sensors adapted to different levels of contamination, offering a solution to the contamination problem of ultrasonic wind speed sensors used in mines under various environmental conditions. The technical solution of this invention replaces traditional signal correction with physical layer spacing compensation: existing technologies only filter or adjust gain for signal attenuation. This invention innovatively uses voltage attenuation to inversely determine the thickness of contamination on the transducer surface, dynamically correcting changes in the effective spacing of the transducers caused by dust accumulation, eliminating ranging errors at their source, rather than passively compensating for signal quality. Simultaneously, this invention replaces passive threshold alarms with proactive maintenance prediction: traditional solutions only issue alarms when the signal falls below a threshold. This invention predicts the remaining usable time by statistically analyzing the voltage drop rate, transforming post-event maintenance into pre-event planning, achieving dynamic recommendations for maintenance cycles, and significantly improving the continuity and operational efficiency of mine ventilation monitoring. This invention uses a microcontroller (MCU) to monitor the voltage amplitude of the transducer's received signal in real time, combining it with time parameters to achieve contamination level assessment, wind speed measurement compensation, and maintenance early warning.

[0023] The following describes in detail, with reference to the accompanying drawings, a compensation method and early warning mechanism for a mine wind speed sensor adapted to different levels of dirtiness according to embodiments of the present invention.

[0024] Example 1: The specific implementation of the compensation method is illustrated in this embodiment using a pair of opposingly installed first and second ultrasonic transducers as an example. The first and second ultrasonic transducers alternately act as the transmitter and receiver during the measurement process, and the microcontroller (…) It is responsible for controlling the launch timing, acquiring signals, and performing calculations.

[0025] In the harsh environment of mines, dust and moisture gradually accumulate on the surface of ultrasonic transducers, leading to a decrease in the strength of the received signal. To quantify the degree of contamination, this invention, after initial sensor installation or cleaning, uses a microcontroller to control the transmitting transducer to emit ultrasonic pulses of a fixed amplitude, and the receiving transducer converts the acoustic signal into an electrical signal. At this time, the analog-to-digital converter (ADC)... The peak voltage of the received signal is collected and recorded as the reference voltage, which corresponds to the cleanliness of the transducer surface. Simultaneously, a minimum measurable voltage threshold is pre-calibrated experimentally; when the received voltage is below this value, the signal-to-noise ratio is too low, compromising the reliability of wind speed measurement. During sensor operation, the microcontroller triggers a measurement at fixed time intervals, using an analog-to-digital converter to acquire the current received voltage in real time.

[0026] During continuous monitoring, the microcontroller not only records the current received voltage It also records the timestamp of each sampling. As dirt accumulates, the voltage decreases, and the rate of voltage drop reflects the speed of dust accumulation in the environment. To smooth out the effects of noise, the rate of change of voltage over time can be calculated using moving average or linear fitting methods, thus predicting the remaining usable time of the transducer.

[0027] Dirt not only causes signal attenuation, but also forms an adhesion layer on the transducer surface, reducing the effective spacing between the front faces of the transducers.

[0028] The specific steps of the compensation method are as follows: Step 1, Reference Voltage Calibration: After initial sensor installation or transducer surface cleaning, reference voltage calibration is performed. The microcontroller controls the first ultrasonic transducer to emit ultrasonic pulses of fixed amplitude. The second ultrasonic transducer receives the acoustic signal and converts it into an electrical signal. The analog-to-digital converter acquires the peak voltage of this signal and records it as the reference voltage of the second ultrasonic transducer. Subsequently, the second ultrasonic transducer is controlled to emit and the first ultrasonic transducer to receive, and the reference voltage of the first ultrasonic transducer is collected. For the sake of simplicity, the following will be referred to as... The reference voltage of each transducer.

[0029] Step 2: Real-time monitoring of current received voltage: During the operation of the mine wind speed sensor, the microcontroller triggers a measurement at fixed time intervals (e.g., every minute). Using the same method as in Step 1, it alternately controls the two transducers to transmit and collects the current received voltage of each transducer as the receiving end in real time. The current received voltage This reflects the degree to which dirt on the transducer surface attenuates the signal strength.

[0030] Step 3, Quantifying the degree of dirtiness: based on the reference voltage and current received voltage Combined with the preset minimum measurable voltage threshold The minimum measurable voltage threshold Through pre-calibration via experimentation, when the voltage is below this minimum measurable voltage threshold... (When the signal-to-noise ratio is too low, measurement reliability cannot be guaranteed), the percentage of dirt is defined based on the relative degree of voltage attenuation. :

[0031] in, , and The unit is volt (Volt). ).

[0032] when When the transducer surface is clean, it indicates that the transducer surface is clean; when As the value gradually increases, it indicates that the degree of dirt accumulation is intensifying; when When this time, it indicates that the voltage has dropped to the lowest measurable voltage threshold. The signal strength is insufficient to support effective measurement, requiring immediate maintenance. This quantitative indicator directly reflects the transducer's condition under environmental influences, providing fundamental data for subsequent compensation and early warning.

[0033] Step 4: Calculation of Adhesion Layer Thickness and Dynamic Correction of Spacing: Dirt adhesion not only leads to signal attenuation but also forms an adhesion layer on the transducer surface, reducing the effective spacing between the front faces of the two transducers. Let the distance between the front faces of the two transducers in the clean state be... The thickness of the coating layer on the surface of each transducer is The actual effective sound path spacing is ,in, , and The units are all millimeters (mm) ).

[0034] In other words, in practical applications, the thickness is calculated based on the real-time voltage attenuation. This leads to the corrected actual distance. In ultrasonic time-of-flight wind speed measurement, the downwind and upwind propagation times are measured by a microcontroller, resulting in the compensated wind speed. Specifically, the thickness of the adhesion layer... With voltage attenuation There is a linear correlation between them, and the proportionality coefficient can be obtained through experimental calibration. (unit: Then we have:

[0035] Substituting the above results into the spacing correction formula, we obtain the actual effective spacing:

[0036] Step 5, Wind speed calculation: Measure the downwind propagation time of the ultrasonic wave. (First ultrasonic transducer transmits, second ultrasonic transducer receives) and headwind propagation time (Second ultrasonic transducer transmits, first ultrasonic transducer receives), utilizing the corrected actual effective distance. Calculate the compensated underground wind speed :

[0037] in, and The units are all seconds ( ), The unit is millimeters per second (m / s) ).

[0038] This formula directly corrects for spacing variations caused by dirt, maintaining high wind speed measurement accuracy even with dust accumulation on the transducer. Meanwhile, due to the current receiving voltage... It updates in real time, and the compensation amount is also dynamically adjusted to adapt to the gradual change in the degree of dirtiness.

[0039] Example 2: proportionality coefficient The calibration method in this embodiment focuses on the scaling factor. The calibration process will be explained in detail. Proportionality coefficient. The method for obtaining the data is as follows: In a laboratory environment, simulated dirt materials (such as a mixture of dust and water) of different thicknesses are artificially coated onto the transducer surface. Simultaneously, the changes in the received voltage and the actual thickness are measured, and the data is determined through linear regression. Value. That is, the amount of voltage attenuation corresponding to each thickness is measured simultaneously. And the actual thickness of the simulated dirty material. After collecting multiple sets of data, a linear regression analysis was used to fit the result. The linear relationship between thickness and the slope is the proportionality coefficient. This calibration process is completed before the sensor leaves the factory, and will... The value is stored in the microcontroller for real-time retrieval.

[0040] Experimental data show that the proportional coefficient of transducers made of different materials varies under different types of contamination. The range of values ​​also varies, and typical data are shown in Table 1 below:

[0041] Example 3: In this embodiment, the early warning mechanism is implemented by adding an early warning step to the existing embodiment 1, thereby enabling intelligent prediction and tiered alerts for maintenance needs.

[0042] Step 6: Voltage drop rate calculation and remaining time prediction: The microcontroller records the current received voltage for each sample in real time. and its corresponding timestamp Store the most recent Secondary sampling data, It is a positive integer greater than or equal to 2. A linear fit is performed using the moving average method or the least squares method, and the slope of the fitted line is taken as the current voltage rate of decrease. (A positive value indicates a decrease).

[0043] Based on common working conditions in underground mines, the voltage drop rate is... The fluctuation range was statistically analyzed, as shown in Table 2 below:

[0044] Based on the current received voltage Minimum measurable voltage threshold and voltage drop rate Predict remaining available time :

[0045] in, and The unit is hour (h). The unit is volts per second (V / s). ).

[0046] This time indicates how long it is expected the voltage will drop to a critical value at the current rate of dust accumulation. Simultaneously, the system can estimate the average rate of dust accumulation in the environment based on long-term statistical trends in voltage drop rates, and dynamically generate recommended maintenance times based on user-defined maintenance cycles (such as weekly or monthly).

[0047] Step 7, Tiered Early Warning Prompts: To provide users with intuitive maintenance guidance, the system provides tiered early warning prompts based on the percentage of dirt or grime. Set multi-level warning thresholds. At least one warning threshold is set. In this embodiment, two warning thresholds are set: Level 1 warning threshold 80%: when the percentage of dirt is... When the soil level reaches 80%, a prompt message indicating the first level of maintenance needs is generated and output (e.g., the system displays "High level of dirt, cleaning recommended soon" via a screen or communication interface). Simultaneously, wind speed measurement (already compensated for spacing) continues, meaning the compensated mine wind speed value is output concurrently. For example, if the current soiling percentage... If the current dirt percentage is 60% and the voltage drop rate is stable, the system can display "Current dirt percentage is 60%, estimated remaining usage time is X days, cleaning is recommended on date Y".

[0048] Level 2 warning threshold 100%: When the percentage of dirt is... Reaching 100% or the current received voltage Below the minimum measurable voltage threshold At this point, a critical alarm is triggered, displaying the message "Severely contaminated, unable to measure, please clean the transducer immediately," and the compensated mine wind speed is stopped. Output or output invalid flag. In addition, the system continuously records voltage drop history, calculates the average voltage drop rate, and dynamically predicts the next recommended maintenance time based on the current level and rate of contamination. For example, if the current contamination level is 50% and the average voltage drop rate is 1% per day, the predicted remaining usage days are 50 days, and the sensor displays "Maintenance and cleaning expected in 50 days." Users can use this information to rationally schedule inspections, avoiding measurement failures or data anomalies caused by transducer contamination. The entire early warning mechanism combines real-time status assessment and trend prediction, effectively improving the sensor's intelligence and reliability.

[0049] Example 4: This embodiment provides a warning mechanism device for mine wind speed sensors that adapt to different levels of contamination, applied to the aforementioned compensation method. The warning mechanism includes: The state quantization module is used to quantize the current received voltage of the transducer's received signal. With reference voltage The percentage of dirt, which represents the degree of dirtiness, is quantified. ; The trend prediction module is used to calculate the voltage drop rate based on historical voltage data. And combined with the current received voltage With the lowest measurable voltage threshold Predict remaining available time ; A graded early warning module is used to determine the level of dirt based on the percentage of dirt. and / or remaining available time It compares the value with a preset threshold and triggers different levels of maintenance or alarm prompts.

[0050] The aforementioned modules can be implemented by a microcontroller with corresponding software programs and integrated into the mining wind speed sensor. This invention, by real-time monitoring of voltage attenuation, achieves quantitative assessment of transducer contamination levels, dynamic spacing compensation, remaining lifespan prediction, and tiered early warning, effectively improving the measurement accuracy and intelligent operation and maintenance level of the mining wind speed sensor in harsh environments.

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A compensation method for a mine wind speed sensor adaptable to different levels of dirt, wherein the sensor comprises a first ultrasonic transducer and a second ultrasonic transducer mounted opposite each other, characterized in that, Includes the following steps: With the transducers in a clean state, obtain the reference voltage of the received signal when each transducer is used as a receiver. ; During sensor operation, the current received voltage of the received signal when each transducer acts as a receiver is acquired in real time. ; Based on the reference voltage and the current received voltage Quantify the degree of dirt on the surface of each transducer; Using the current received voltage relative to reference voltage Attenuation Calculate the thickness of the surface deposits on the transducer caused by dirt adhesion. ; Based on the thickness of the adhesion layer The initial spacing of the transducers in a clean state Dynamic correction is performed to obtain the actual effective spacing. ; Measuring the downwind propagation time of ultrasonic waves and headwind propagation time And using the corrected actual effective spacing Calculate the compensated underground wind speed .

2. The compensation method according to claim 1, characterized in that, The use of the current received voltage relative to reference voltage Attenuation Calculate the thickness of the adhesion layer The specific steps are as follows: using a pre-calibrated scaling factor Calculate the thickness of the adhesion layer The proportionality coefficient Voltage attenuation was calibrated experimentally. With the thickness of the adhesion layer The correspondence was obtained.

3. The compensation method according to claim 2, characterized in that, The proportionality coefficient The calibration method is as follows: In a laboratory environment, simulated contaminant materials of different thicknesses are coated on the transducer surface. The change in received voltage and the actual thickness of the simulated contaminant material are measured simultaneously. The voltage attenuation is determined through linear regression analysis. The proportionality coefficient between thickness and other factors .

4. The compensation method according to claim 2, characterized in that, The compensated underground wind speed The calculation formula is: 。 5. The compensation method according to claim 1, characterized in that, The quantification of the degree of contamination on the surface of each transducer is specifically as follows: Based on the reference voltage Current received voltage and the preset minimum measurable voltage threshold Define the percentage of dirt. .

6. The compensation method according to claim 5, characterized in that, It also includes early warning steps: Real-time recording of current received voltage Calculate the rate of voltage decrease over time using the corresponding timestamps. ; Based on the current received voltage Minimum measurable voltage threshold and voltage drop rate Predict remaining available time ; Based on the degree of soiling or the remaining available time It generates and outputs corresponding maintenance prompts.

7. The compensation method according to claim 6, characterized in that, The process of generating and outputting corresponding maintenance prompts based on the degree of dirtiness specifically involves setting at least one warning threshold; when the percentage of dirtiness... When the warning threshold is reached, a corresponding tiered warning prompt will be issued.

8. The compensation method according to claim 6, characterized in that, The calculated voltage rate of decrease over time The specific steps are: store the most recent The voltage samples and their corresponding timestamps are linearly fitted using either the moving average method or the least squares method. The slope of the fitted line is then used as the current voltage rate of decrease. .

9. The compensation method according to claim 7, characterized in that, The tiered early warning notifications include: When the percentage of dirt Reaching the Level 1 warning threshold At that time, a prompt message representing the first level of maintenance needs is generated and output, while continuing to output the compensated underground wind speed value. When the percentage of dirt Reaching the Level II warning threshold Or the current received voltage Below the minimum measurable voltage threshold At that time, a serious alarm was triggered, and the mine's underground wind speed stopped after compensation. Output or output invalid flag; Among them, the secondary warning threshold Greater than the first-level warning threshold .

10. A mine wind speed sensor early warning mechanism adaptable to different levels of contamination, applied to the compensation method as described in any one of claims 1 to 9, characterized in that, include: The state quantization module is used to quantize the current received voltage of the transducer's received signal. With reference voltage The percentage of dirt, which represents the degree of dirtiness, is quantified. ; The trend prediction module is used to calculate the voltage drop rate based on historical voltage data. And combined with the current received voltage With the lowest measurable voltage threshold Predict remaining available time ; A graded early warning module is used to determine the degree of dirt based on the percentage of dirt. and / or the remaining available time It compares the value with a preset threshold and triggers different levels of maintenance or alarm prompts.

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