A piezoelectric rain gauge calibration device, method and system

Abstract

The present application belongs to the technical field of sensor calibration, and particularly relates to a piezoelectric rain gauge calibration device, method and system. The piezoelectric rain gauge calibration device comprises an ultrasonic vibration module, a flexible coupling module, a signal acquisition and processing module, a signal control module and a power supply module, and each module cooperates to realize non-contact calibration of the piezoelectric rain gauge. The present application realizes non-contact vibration excitation through ultrasonic vibration coupling technology, dynamically adjusts vibration parameters in combination with an algorithm, realizes high-precision calibration of the piezoelectric rain gauge in a full rain intensity range (0.1-200 mm / h), and simultaneously takes into account the portability of the device, and is suitable for field calibration scenes.

Description

Technical Field

[0001] This invention belongs to the field of sensor calibration technology, specifically relating to a piezoelectric rain gauge calibration device, method, and system. Background Technology

[0002] Piezoelectric rain gauges are widely used in meteorological observation, hydrological monitoring, and geological disaster early warning systems due to their advantages such as fast response, wide measurement range, and low maintenance costs. Their working principle involves using a piezoelectric sensor to detect the vibration signal generated by raindrops hitting a panel, converting the vibration signal into an electrical signal, and then using an algorithm to calculate rainfall data. The accuracy of rainfall monitoring data directly determines the reliability of subsequent data-driven decision-making; therefore, regular calibration is necessary to maintain performance stability and data accuracy.

[0003] Currently, most piezoelectric rain gauge calibration methods employ laboratory-based artificial rainfall simulation calibration. This involves constructing an artificial rainfall simulation hall and controlling the rainfall environment to achieve calibration. While this method offers high accuracy, practical applications require disassembling and transporting the field equipment to the laboratory, resulting in a long calibration cycle and cumbersome procedures, impacting the continuity of equipment operation. Outdoor rain gauge comparative calibration typically involves deploying a standard rain gauge (such as a tipping bucket rain gauge or a graduated cylinder rain gauge) next to the rain gauge to be calibrated, using the measurement data from the standard device as a benchmark for comparative calibration. However, standard rain gauge calibration is costly and unsuitable for on-site calibration at remote field sites. Furthermore, calibration requires waiting for natural or artificial rainfall, making the calibration cycle highly susceptible to weather conditions and preventing real-time calibration.

[0004] Therefore, there is an urgent need for a real-time, rapid, accurate, and portable calibration device and system that does not require the construction of a simulated rainfall hall in a professional laboratory, does not require waiting for natural rainfall, and can be carried out directly in the field to solve the industry problem that existing technologies cannot achieve efficient field calibration. Summary of the Invention

[0005] In view of this, the present invention provides a piezoelectric rain gauge calibration device, method and system, which can achieve high-precision calibration of piezoelectric rain gauges across the entire rainfall intensity range (0.1-200 mm / h), while also taking into account the portability of the device and adapting to field calibration scenarios.

[0006] To achieve the objectives of this invention, the following technical solutions are provided.

[0007] A piezoelectric rain gauge calibration device, comprising: The ultrasonic vibration module is used to generate high-frequency sinusoidal vibrations with controllable frequency and amplitude to simulate the vibration signals of raindrops hitting the rain gauge panel under different rainfall intensities. The flexible coupling module, including a flexible coupling rod and a vacuum suction cup, is used to transmit the vibration generated by the ultrasonic vibration module to the piezoelectric rain gauge panel and avoid mechanical contact that could cause wear to the panel. The signal acquisition and processing module is used to acquire the electrical signal output by the piezoelectric rain gauge and to perform filtering, amplification and analog-to-digital conversion on the signal. The signal control module stores the mapping relationship between standard vibration parameters and electrical signals, compares the deviation between the acquired measured electrical signals and the standard electrical signals, and dynamically adjusts the vibration parameters of the ultrasonic vibration module; and The power supply module is used to provide power to each module.

[0008] The ultrasonic vibration module includes an ultrasonic generator and an ultrasonic transducer. The ultrasonic generator has a continuously adjustable operating frequency of 50-800Hz, a frequency accuracy of ±0.1Hz, and an adjustable output power of 0.5-10W, supporting both sine wave and square wave vibration waveforms. The ultrasonic transducer is made of piezoelectric ceramic material, and its vibration amplitude is adjustable in steps of 0.01-10μm.

[0009] The flexible coupling rod is made of carbon fiber reinforced silicone, and its two ends are connected to the ultrasonic transducer and the vacuum suction cup respectively by threads. The vacuum suction cup is made of nitrile rubber, and a one-way exhaust valve is provided on the top of the suction cup. By manually pressing to expel air and generate negative pressure, the coupling rod is fixed to the center of the rain gauge panel.

[0010] The signal acquisition and processing module is connected to the signal output terminal of the piezoelectric rain gauge and supports differential signal acquisition. It includes a low-pass filter and an instrumentation amplifier to amplify the weak electrical signal output by the rain gauge to a standard signal. A high-precision AD converter is used to convert the analog signal into a digital signal and transmit it to the signal control module.

[0011] The signal control module includes a microcontroller with a built-in floating-point arithmetic unit and a neural network acceleration unit, supporting the local execution of lightweight AI models; it also has a built-in preset rain intensity-vibration parameter-standard electrical signal mapping library, and updates new operating conditions via a USB interface.

[0012] The power supply module has a built-in high-capacity lithium battery that supports continuous calibration for more than 8 hours and is equipped with a USB-C fast charging interface and a solar charging interface.

[0013] This invention provides a method for calibrating a piezoelectric rain gauge, using the piezoelectric rain gauge calibration device described in this invention, and includes the following steps: Based on the preset correspondence between rainfall intensity and vibration parameters, the ultrasonic vibration module outputs a standard vibration that matches the target rainfall intensity, causing the piezoelectric rain gauge to generate a vibration response and output a measured electrical signal. The standard electrical signal corresponding to the vibration parameter is retrieved from the mapping library of the signal control module and compared with the measured electrical signal obtained by the signal acquisition and processing module to calculate the deviation between the two. Using a lightweight AI algorithm tailored for piezoelectric rain gauge calibration scenarios, a calibration coefficient capable of offsetting the deviation is calculated based on the deviation; and The calibration coefficient is written into the main control unit of the piezoelectric rain gauge to correct the rainfall data output in subsequent measurements.

[0014] Wherein, the deviation is the percentage of the difference between the measured electrical signal and the standard electrical signal relative to the standard electrical signal; the calibration coefficient is equal to the difference obtained by dividing by and subtracting the percentage.

[0015] The lightweight AI algorithm uses a BP neural network based on gradient descent optimization to construct a control loop of vibration excitation, signal acquisition, deviation calculation, and parameter adjustment. The algorithm takes ultrasonic vibration parameters and measured electrical signals from a rain gauge as inputs and outputs parameter adjustment amounts, i.e., calibration coefficients, to ensure that the deviation between the acquired electrical signals and the standard electrical signals is within a preset threshold.

[0016] This invention also provides a piezoelectric rain gauge calibration system, including the piezoelectric rain gauge calibration device of this invention and a cloud data platform. The calibration device is connected to the main control unit of the piezoelectric rain gauge to be calibrated via an RS485 interface, and is used to collect electrical signals and write calibration coefficients. The calibration device has a built-in wireless communication module to encrypt and upload calibration data to the cloud data platform. The cloud data platform provides data storage, data analysis, and device management functions, and supports connection with meteorological and hydrological monitoring networks.

[0017] Beneficial effects 1. This invention achieves non-contact vibration excitation of the rain gauge panel through the coordinated operation of an ultrasonic vibration module and a flexible coupling module. The flexible coupling rod is made of carbon fiber reinforced silicone material, and with the negative pressure adsorption of the vacuum suction cup, it ensures efficient and attenuated transmission of vibration energy, while avoiding the wear and damage to the panel caused by traditional mechanical knocking or contact calibration. This significantly extends the service life of the rain gauge, making it particularly suitable for field environments requiring frequent calibration.

[0018] 2. The ultrasonic vibration module in this invention can generate high-frequency sinusoidal vibrations covering the entire rainfall intensity range of 0.1-200 mm / h, simulating everything from drizzle to torrential rain. The operating frequency is continuously adjustable from 50-800 Hz, and the amplitude is adjustable in steps from 0.01-10 μm. It is compatible with the entire measurement range of existing piezoelectric rain gauges, solving the technical problem that traditional calibration methods cannot cover extreme rainfall scenarios, and improving the versatility and adaptability of the calibration device.

[0019] 3. This invention boasts excellent portability and rapid on-site calibration capabilities. The power supply module features a built-in high-capacity lithium battery and supports solar charging. A single calibration takes no more than 5 minutes, allowing a single person to carry it to remote field sites for calibration. The device eliminates the need to disassemble the equipment to be calibrated, wait for natural rainfall, or rely on a laboratory simulated rainfall hall, completely solving the problems of long cycles, cumbersome procedures, and disruptions to continuous equipment operation associated with traditional calibration methods. It achieves real-time, efficient, and accurate on-site calibration.

[0020] 4. This invention achieves closed-loop dynamic parameter adjustment through a rain intensity-vibration parameter-standard electrical signal mapping library built into the signal control module and a lightweight AI model. The control module compares the collected measured electrical signals with the standard electrical signals, calculates the deviation, and automatically corrects the vibration parameters or generates calibration coefficients. High-precision calibration can be completed on-site without relying on cloud computing power, and the calibration deviation can be controlled within ±2%, significantly improving the automation level and accuracy of calibration.

[0021] 5. This invention employs a BP neural network algorithm based on gradient descent optimization to construct the control loop. It uses ultrasonic vibration parameters and measured electrical signals from the rain gauge as inputs, and dynamically outputs parameter adjustments, i.e., calibration coefficients. This algorithm can adapt to the nonlinear response characteristics of different rain gauge models, ensuring rapid convergence to the acceptable deviation range after multiple iterations. Simultaneously, it automatically generates a calibration log containing calibration time, operating parameters, deviation values, and comprehensive calibration coefficients, facilitating data traceability and quality control.

[0022] 6. The calibration system provided by this invention combines a portable calibration device with a cloud data platform, enabling encrypted uploading and remote management of calibration data via an RS485 interface and a wireless communication module. The cloud data platform provides data storage, analysis, remote equipment monitoring, and batch management of calibration logs. It can seamlessly connect with meteorological and hydrological monitoring networks to achieve linked analysis of rain gauge calibration status and monitoring data, meeting the standardized requirements of metrological calibration. It is suitable for large-scale deployment and centralized operation and maintenance of rain gauge calibration networks with multiple field stations. Attached Figure Description

[0023] Figure 1 This is a structural diagram of an embodiment of the device of the present invention.

[0024] Figure 2 This is a schematic diagram of the calibration process in an embodiment of the method of the present invention.

[0025] Figure 3 This is a schematic diagram of an embodiment of the system of the present invention. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0027] This invention provides a piezoelectric rain gauge calibration device, comprising an ultrasonic vibration module, a flexible coupling module, a signal acquisition and processing module, a signal control module, and a power supply module, such as... Figure 1 As shown, the modules work together to achieve non-contact calibration of the piezoelectric rain gauge.

[0028] The core components of the ultrasonic vibration module include an ultrasonic generator and an ultrasonic transducer, used to generate high-frequency sinusoidal vibrations with controllable frequency and amplitude to simulate the vibration signals of raindrops impacting the rain gauge panel under different rainfall intensities. The ultrasonic generator uses a high-frequency ultrasonic oscillation chip (operating frequency continuously adjustable from 50-800Hz, frequency accuracy ±0.1Hz), with an adjustable output power of 0.5-10W, supporting both sine and square wave vibration waveforms. The ultrasonic transducer is electrically connected to the ultrasonic generator, using piezoelectric ceramic material to ensure concentrated transmission of vibration energy, converting electrical signals into mechanical vibrations, with vibration amplitude adjustable in steps from 0.01-10μm. The ultrasonic vibration module has a built-in vibration parameter adjustment unit, including a frequency adjustment knob, an amplitude adjustment knob, and a potentiometer, supporting precise manual adjustment. It also reserves an RS485 interface for bidirectional communication with the control module, enabling one-button switching between "manual mode" and "automatic mode." In automatic mode, the control module outputs commands to dynamically adjust the vibration parameters.

[0029] The flexible coupling module transmits vibrations generated by the ultrasonic transducer to the piezoelectric rain gauge panel without attenuation, while avoiding mechanical contact and wear on the panel. Its core components include a flexible coupling rod and a vacuum suction cup. The flexible coupling rod is made of carbon fiber reinforced silicone, with its two ends connected to the ultrasonic transducer and vacuum suction cup respectively via threads. The carbon fiber layer ensures efficient vibration transmission, while the silicone layer buffers vibration impact. The vacuum suction cup is made of nitrile rubber (with the same diameter as the piezoelectric panel), and a one-way exhaust valve is located on the top of the suction cup. By manually pressing the valve, air is expelled to create negative pressure, fixing the coupling rod to the center of the rain gauge panel and ensuring seamless vibration transmission.

[0030] The signal acquisition and processing module is used to acquire the electrical signal output from the piezoelectric rain gauge, filter and amplify the signal, and provide calibration data for the control module. This module connects to the signal output terminal of the piezoelectric rain gauge, supports differential signal acquisition, and suppresses common-mode interference. It includes a low-pass filter (cutoff frequency 1kHz) and an instrumentation amplifier (adjustable gain 10-1000 times) to amplify the weak electrical signal (0-10mV) output by the rain gauge to a 0-5V standard signal. A high-precision AD converter is used to convert the analog signal into a digital signal and transmit it to the control module.

[0031] The control module stores the mapping relationship between standard vibration parameters and electrical signals, compares the deviation between the acquired signal and the standard signal, and dynamically adjusts the ultrasonic vibration parameters to achieve calibration. The module includes a microcontroller (with a built-in floating-point unit and neural network acceleration unit), supporting local execution of lightweight AI models without relying on cloud computing power. It has a built-in pre-set "rain intensity-vibration parameter-standard electrical signal" mapping library, which can be updated via a USB interface for new operating conditions.

[0032] In summary, this invention achieves vibration transmission through a flexible coupling rod and a vacuum suction cup, avoiding the damage to the rain gauge panel caused by traditional mechanical impacts. The non-contact calibration method avoids or reduces panel damage, extending the rain gauge's lifespan. The ultrasonic vibration module provides vibration signals across the entire range of rainfall intensity, from drizzle to torrential downpours, covering the full measurement range of existing piezoelectric rain gauges and adapting to extreme rainfall monitoring scenarios. Furthermore, it features a portable design with a built-in high-capacity lithium battery, supports solar charging, and a single calibration takes ≤5 minutes, allowing for calibration by a single person at remote field sites, achieving real-time, efficient, and accurate sensor calibration. Finally, calibration data is transmitted encrypted, and the cloud platform supports data traceability and batch management, meeting the standardized requirements of metrological calibration.

[0033] This invention also provides a calibration method for a piezoelectric rain gauge, implemented using the device of this invention. The core logic of the calibration is to simulate rainfall through ultrasonic vibration, calculate the correction coefficient by comparing the signal deviation, and finally write the correction coefficient into the rain gauge, achieving contactless calibration. The entire process is as follows: Figure 2 As shown, it includes the following steps: Based on the correspondence between "rainfall intensity and vibration parameters," the ultrasonic vibration module outputs a standard vibration matching the target rainfall intensity. The rain gauge generates a vibration response and outputs an electrical signal. The control module retrieves the "standard electrical signal" corresponding to this vibration parameter from the mapping library and compares it with the "measured electrical signal" from the rain gauge acquired by the signal acquisition module, calculating the deviation θ between the two. θ=(V1-V0) / V0×100% Where: θ is the electrical signal deviation (unit: %), V1 is the measured electrical signal of the rain gauge (unit: V), and V0 is the standard electrical signal in the mapping library (unit: V).

[0034] The AI ​​algorithm calculates the calibration coefficient K that can offset the deviation based on the deviation value: K=1 / (1-θ / 100) Where: K is the calibration coefficient, and the larger the deviation of θ, the greater the adjustment range of the coefficient.

[0035] The calibration coefficient is written into the main control unit of the rain gauge. When the rain gauge subsequently measures actual rainfall, it will automatically use this coefficient to correct the electrical signal, thereby outputting accurate rainfall data.

[0036] P(calibration)=P0×K Where: P(calibration) is the corrected rainfall of the rain gauge (unit: mm / h), P0 is the measured value of the rain gauge before calibration (unit: mm / h), and K is the calibration coefficient.

[0037] The control module constructs the control logic of "vibration excitation - signal acquisition - deviation calculation - parameter adjustment" based on the BP neural network algorithm optimized by gradient descent, inputs "ultrasonic vibration parameter - measured electrical signal of rain gauge", and outputs the parameter adjustment amount, that is, the calibration coefficient, to ensure that the deviation between the acquired electrical signal and the standard electrical signal is ≤±2%. After the calibration is completed, a calibration log is automatically generated, which includes calibration time, working condition parameters (vibration frequency / amplitude), measured electrical signal value, deviation value, and comprehensive calibration coefficient, and supports export through the USB interface or upload to the cloud via the 4G module.

[0038] The power supply module has a built-in 20000mAh lithium battery, supports continuous calibration for ≥8 hours, is equipped with a USB-C fast charging interface and a solar charging interface, and the charging time is ≤3 hours.

[0039] The present invention further provides a piezoelectric rain gauge calibration system, which includes a calibration device and a cloud data platform. Based on the above piezoelectric rain gauge calibration device, the piezoelectric rain gauge calibration that realizes data interaction with the piezoelectric rain gauge to be calibrated and the cloud data platform through the communication module is as Figure 3 shown in the figure.

[0040] The piezoelectric rain gauge calibration device is connected to the main control unit of the rain gauge to be calibrated through the RS485 interface. On the one hand, it collects the real-time electrical signal of the rain gauge, and on the other hand, writes the calibration coefficient into the rain gauge to complete the parameter update. The calibration device has a built-in 4G full-network communication module, which uses an encrypted protocol to directly upload calibration data (vibration parameters, electrical signals, deviation values, calibration logs) to the cloud data platform, supporting remote viewing of calibration records and batch management of multiple calibration devices. The cloud data platform provides functions of data storage, data analysis, and equipment management (remote monitoring of the power and working status of the calibration device), and also supports docking with meteorological and hydrological monitoring networks to realize the linkage analysis of the rain gauge calibration status and monitoring data.

[0041] The overall working process of the system of the present invention is illustrated by the field on-site calibration of the piezoelectric rain gauge with model RT001: 1. Device deployment Fix the calibration device directly in front of the piezoelectric rain gauge to be calibrated, ensuring the device is coaxial with the rain gauge. Connect one end of the flexible coupling rod (made of carbon fiber reinforced silicone) to the ultrasonic transducer via threads, and install a 20cm nitrile rubber vacuum suction cup on the other end. The suction cup size should be the same as the effective panel size of the piezoelectric sensor. Press the suction cup exhaust valve to expel air, allowing the suction cup to adhere tightly to the center of the RT001 rain gauge panel, ensuring a tight fit between the suction cup and the panel, and that the vibration transmission direction is perpendicular to the panel. Connect the signal acquisition interface of the calibration device to the signal output terminal of the rain gauge, and connect the calibration device to the main control unit of the rain gauge using an RS485 cable. Start the power supply module to prepare for calibration.

[0042] Turn on the calibration device, select the "automatic calibration" mode through the control module, and call up the corresponding working condition data from the built-in "rain intensity-vibration parameter-standard electrical signal" mapping library.

[0043] 2. Calibration parameter settings Based on the rainfall monitoring range of the RT001 piezoelectric rain gauge, five sets of calibration conditions covering different rainfall intensities were generated, with specific parameters as follows:

[0044] 3. Calibration execution The calibration device control module sends a command, and the ultrasonic vibration module outputs a 50Hz, 0.01μm sinusoidal vibration, which is transmitted to the rain gauge panel via a flexible coupling rod. The signal acquisition module simultaneously acquires the electrical signals from the rain gauge. .

[0045] The control module calculates θ=-4% using the formula θ=(V1-V0) / V0×100%, substituting V1=0.048V and V0=0.05V. This deviation exceeds the ±2% threshold. The BP neural network algorithm outputs an adjustment command based on the deviation value. The control module sends a parameter adjustment signal to the ultrasonic vibration module via the RS485 interface, increasing the amplitude from 0.01μm to 0.0104μm (keeping the frequency constant at 50Hz). The ultrasonic module outputs vibration according to the adjusted parameters. The signal acquisition module again acquires the electrical signal V2=0.0499V and recalculates the deviation θ=(0.0499-0.05) / 0.05×100%=-0.2% (≤±2%). Calibration for condition 1 is qualified. Using the formula K=1 / (1-θ / 100), substituting θ=-0.2%, the calibration coefficient K1=1.002 is calculated. Repeat the above steps to complete the calibration for operating conditions 2-5, and finally calculate the comprehensive calibration coefficient K (comprehensive) = 1.007.

[0046] The value K(overall) = 1.007 was written to the RT001 rain gauge main control unit via the RS485 interface, and the rain gauge automatically updated and corrected its parameters. The control module automatically generated a calibration log, which included: calibration time, rain gauge model (RT001), vibration parameters / measured electrical signals / deviation values / single-condition coefficients for 5 operating conditions, and the overall calibration coefficient (1.007). The calibration device uploaded the calibration log to the cloud data platform via a 4G full-network module, completing the calibration of this piezoelectric rain gauge.

[0047] The specific meanings of the technical terms, English abbreviations, and letters that may be used in this invention are explained below: This invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered within the scope of protection of this invention.

Claims

1. A piezoelectric rain gauge calibration device, characterized in that, include: The ultrasonic vibration module is used to generate high-frequency sinusoidal vibrations with controllable frequency and amplitude to simulate the vibration signals of raindrops hitting the rain gauge panel under different rainfall intensities. The flexible coupling module, including a flexible coupling rod and a vacuum suction cup, is used to transmit the vibration generated by the ultrasonic vibration module to the piezoelectric rain gauge panel and avoid mechanical contact that could cause wear to the panel. The signal acquisition and processing module is used to acquire the electrical signal output by the piezoelectric rain gauge and to perform filtering, amplification and analog-to-digital conversion on the signal. The signal control module stores the mapping relationship between standard vibration parameters and electrical signals, compares the deviation between the acquired measured electrical signals and the standard electrical signals, and dynamically adjusts the vibration parameters of the ultrasonic vibration module; and The power supply module is used to provide power to each module.

2. The piezoelectric rain gauge calibration device according to claim 1, characterized in that, The ultrasonic vibration module includes an ultrasonic generator and an ultrasonic transducer; the ultrasonic generator has a continuously adjustable operating frequency of 50-800Hz, a frequency accuracy of ±0.1Hz, and an adjustable output power of 0.5-10W, supporting both sine wave and square wave vibration waveforms; the ultrasonic transducer is made of piezoelectric ceramic material, and the vibration amplitude is adjustable in steps of 0.01-10μm.

3. The piezoelectric rain gauge calibration device according to claim 1, characterized in that, The flexible coupling rod is made of carbon fiber reinforced silicone. Both ends of the rod are connected to the ultrasonic transducer and the vacuum suction cup respectively through threads. The vacuum suction cup is made of nitrile rubber. A one-way exhaust valve is provided on the top of the suction cup. By manually pressing to expel air and generate negative pressure, the coupling rod is fixed to the center of the rain gauge panel.

4. The piezoelectric rain gauge calibration device according to claim 1, characterized in that, The signal acquisition and processing module is connected to the signal output terminal of the piezoelectric rain gauge and supports differential signal acquisition. It includes a low-pass filter and an instrumentation amplifier to amplify the weak electrical signal output by the rain gauge to a standard signal. A high-precision AD converter is used to convert the analog signal into a digital signal and transmit it to the signal control module.

5. The piezoelectric rain gauge calibration device according to claim 1, characterized in that, The signal control module includes a microcontroller with a built-in floating-point arithmetic unit and a neural network acceleration unit, supporting the local execution of lightweight AI models; it also has a built-in preset rain intensity-vibration parameter-standard electrical signal mapping library, and updates new operating conditions via a USB interface.

6. The piezoelectric rain gauge calibration device according to any one of claims 1-5, characterized in that, The power supply module has a built-in high-capacity lithium battery that supports continuous calibration for more than 8 hours and is equipped with a USB-C fast charging interface and a solar charging interface.

7. A calibration method for a piezoelectric rain gauge, characterized in that, The piezoelectric rain gauge calibration device according to any one of claims 1 to 6 includes the following steps: Based on the preset correspondence between rainfall intensity and vibration parameters, the ultrasonic vibration module outputs a standard vibration that matches the target rainfall intensity, causing the piezoelectric rain gauge to generate a vibration response and output a measured electrical signal. The standard electrical signal corresponding to the vibration parameter is retrieved from the mapping library of the signal control module and compared with the measured electrical signal obtained by the signal acquisition and processing module to calculate the deviation between the two. Using a lightweight AI algorithm tailored for piezoelectric rain gauge calibration scenarios, a calibration coefficient capable of offsetting the deviation is calculated based on the deviation; and The calibration coefficient is written into the main control unit of the piezoelectric rain gauge to correct the rainfall data output in subsequent measurements.

8. The method according to claim 7, characterized in that, The deviation is the percentage of the difference between the measured electrical signal and the standard electrical signal relative to the standard electrical signal; the calibration coefficient is equal to the difference obtained by dividing by and subtracting the percentage.

9. The method according to claim 7 or 8, characterized in that, The lightweight AI algorithm uses a BP neural network based on gradient descent optimization to construct a control loop of vibration excitation, signal acquisition, deviation calculation, and parameter adjustment. The algorithm takes ultrasonic vibration parameters and measured electrical signals from a rain gauge as inputs and outputs parameter adjustment amounts, i.e., calibration coefficients, to ensure that the deviation between the acquired electrical signals and the standard electrical signals is within a preset threshold.

10. A piezoelectric rain gauge calibration system, characterized in that, The invention includes a piezoelectric rain gauge calibration device and a cloud data platform as described in any one of claims 1 to 6. The calibration device is connected to the main control unit of the piezoelectric rain gauge to be calibrated via an RS485 interface for collecting electrical signals and writing calibration coefficients. The calibration device has a built-in wireless communication module that encrypts and uploads the calibration data to the cloud data platform. The cloud data platform provides data storage, data analysis, and device management functions, and supports connection with meteorological and hydrological monitoring networks.

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