Windscreen wiper control method based on piezoelectric ceramics

Abstract

The invention relates to the technical field of automotive electronics and electrics, in particular to a windscreen wiper control method based on piezoelectric ceramics, which directly detects elastic waves of rainwater through a piezoelectric ceramic sensor, confirms the authenticity of rainfall from the physical level, thoroughly avoids the interference of light change, dust coverage, foreign matter shielding and the like on a light rainfall sensor, and improves the control accuracy of the windscreen wiper. The core pain point that a traditional system scrapes without rain and does not scrape when it rains is solved, the double-sensor integral product logic is adopted, the two dimensions of rainfall existence and intensity are considered, a dynamic threshold value adjusting mechanism is combined, the working state of a windscreen wiper is highly matched with the actual rainfall condition, the control refinement level is improved, and the control precision is improved. And an original light rainfall sensor and a windscreen wiper executing mechanism of the vehicle do not need to be replaced, only the piezoelectric ceramic sensor and the signal conditioning module need to be additionally arranged, the light rainfall sensor for synchronous detection is matched, it is guaranteed that the windscreen wiper responds to rainfall intensity fluctuation in time, and driving safety is further guaranteed.

Description

Technical Field

[0001] This invention relates to the field of automotive electronics and electrical technology, and more specifically, to a windshield wiper control method based on piezoelectric ceramics. Background Technology

[0002] Automatic wiper functions use sensors to detect precipitation on the windshield and the control system adjusts the speed and interval of the wipers to ensure clear visibility for the driver. Most existing automatic wiper systems use light sensors or microwave radar sensors. Light sensors determine precipitation by reflecting and refractioning light, while microwave radar sensors determine the intensity and location of precipitation by emitting and detecting the reflection of microwave signals.

[0003] Piezoelectric ceramics are special materials that exhibit both piezoelectric and inverse piezoelectric effects. The piezoelectric effect refers to the minute deformation of the crystal structure when subjected to external force or pressure, leading to the separation of positive and negative charges. The inverse piezoelectric effect refers to the rearrangement of positive and negative charges when an external electric field is applied, causing minute deformation of the crystal structure. Based on these two effects, piezoelectric ceramics can achieve the interconversion of mechanical energy and electrical energy.

[0004] In current technologies, light rain sensors are easily affected by changes in light (such as from cloudy to sunny days, sudden changes in light at tunnel entrances and exits), dust cover, or obstruction by foreign objects (such as fallen leaves or bird droppings adhering to the sensor surface), which can lead to distortion of the detection signal. This can cause problems such as automatic wipers "wiping randomly when there is no rain" (the sensor misjudges precipitation) or "not wiping when it rains" (the sensor does not recognize actual precipitation), which seriously affects the driving experience and driving safety. Therefore, the present invention provides a wiper control method based on piezoelectric ceramics. Summary of the Invention

[0005] The purpose of this invention is to provide a windshield wiper control method based on piezoelectric ceramics to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides a windshield wiper control method based on piezoelectric ceramics, the method steps of which are as follows: S1: A piezoelectric ceramic sensor is used to collect precipitation signals, which are then converted into electrical signals. The electrical signals are preprocessed and output as digital signals. The threshold levels are then divided, and an integral is assigned to each level to obtain the threshold integral. S2: Set the original integral trigger lower limit of the wipers in various working states, dynamically adjust the trigger lower limit through a threshold adjustment algorithm, establish a correlation model between vehicle speed and threshold adjustment range, and then dynamically adjust the trigger lower limit again. S3: A light rain sensor is used to convert the received light signal into an electrical signal, calculate the photocurrent and photoelectric voltage, preprocess the photoelectric voltage, and output a digital signal. The amount of change in light intensity is calculated, and threshold levels are assigned. An integral is then applied to obtain the precipitation integral. S4: Calculate the total integral of the wipers, set the interval threshold, and determine the output wiper working status command. S5: Calculate the false trigger rate and response time, and calculate the visual clarity score through subjective scoring method. Set the original adjustment range, calculate the optimized adjustment range, and the number of consecutive no-signal wipers.

[0007] Preferably, the specific principle of converting the precipitation signal into an electrical signal in S1 is as follows: The piezoelectric ceramic sensor utilizes the piezoelectric effect (operating when rain hits the windshield) to generate elastic waves. When the elastic waves are transmitted to the piezoelectric ceramic sensor, they cause a slight deformation in its crystal structure, which in turn leads to the separation of positive and negative charges inside, generating an electrical signal. The preprocessing of the electrical signal includes filtering, amplification, and conversion of the continuous electrical signal into a digital signal.

[0008] Preferably, the calculation expression for the electrical signal filtering is: the transfer function equals 1 divided by the product of the resistance value and the capacitance value multiplied by the complex frequency s, plus 1. The calculation expression for the electrical signal amplification is: the voltage amplification factor equals the resistance value of the feedback resistor divided by the resistance value of the input resistor, and the result is negative. The calculation expression for the conversion of the electrical signal to a digital signal is: the analog voltage minus the minimum value of the voltage range is defined as the first value, the difference between the maximum value and the minimum value of the voltage range is defined as the second value, the first value is divided by the second value, and then multiplied by 2 to the power of n.

[0009] Preferably, the logic for the threshold level is: to convert the digital signal... Divided into 5 intervals, each interval corresponds to a threshold level. , , , The threshold level is assigned a corresponding integral value to obtain the threshold integral.

[0010] Preferably, the logic of the threshold adjustment algorithm for dynamically adjusting the trigger lower limit is as follows: when the piezoelectric ceramic sensor detects an elastic wave, the threshold adjustment algorithm is used to automatically lower the wiper trigger threshold; if the sensor does not detect an elastic wave, the threshold adjustment algorithm is used to automatically raise the wiper trigger threshold. The calculation formula of the threshold adjustment algorithm is: the original trigger lower limit multiplied by 1 minus the adjustment ratio. The logic of the trigger lower limit after dynamic adjustment is: the trigger lower limit adjusted by the threshold adjustment algorithm multiplied by 1 minus the adjustment coefficient.

[0011] Preferably, the photocurrent is equal to the photoelectric conversion efficiency multiplied by the electron charge, then multiplied by the ratio of the incident light wavelength to the product of Planck's constant and the speed of light, and then multiplied by the incident light power and the photodiode's light-receiving area. The photoelectric voltage is equal to the photocurrent multiplied by the load resistance. The digital signal... The first value is defined as the difference between the photoelectric voltage and the minimum value of the voltage range. The second value is defined as the difference between the maximum value and the minimum value of the voltage range. The first value is then divided by the second value, and finally multiplied by 2 to the power of n.

[0012] Preferably, the change in light intensity is equal to a scaling factor multiplied by the digital signal. With the offset added, the determination logic for the precipitation integral is the same as that for the threshold integral.

[0013] Preferably, the total integral of the wiper is equal to the threshold integral multiplied by the precipitation integral. An interval threshold is set, and the total integral is compared with the interval threshold to determine and output the working status command of the wiper.

[0014] Preferably, the false trigger rate is equal to the number of false triggers divided by the total number of tests multiplied by 100%, the wiper response time is equal to the wiper start time minus the time of the effective signal detected by the sensor, and the visual clarity score is equal to the sum of the scores of all scorers divided by the number of scorers.

[0015] Preferably, the adjustment range is equal to the original adjustment range multiplied by the adjustment coefficient, and the number of consecutive no-signal times is equal to the no-signal time minus the detection period.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By directly detecting rainwater elastic waves using piezoelectric ceramic sensors, the authenticity of precipitation is confirmed from a physical perspective. This completely avoids interference from changes in light, dust cover, and foreign object obstruction to the light and rain measurement sensor, solving the core pain points of traditional systems such as "wiping randomly when there is no rain" and "not wiping when it rains". It adopts "dual sensor integral product" logic, taking into account both the "existence" and "intensity" of precipitation. Combined with a dynamic threshold adjustment mechanism, the wiper working status is highly matched with the actual precipitation situation, improving the level of control precision.

[0017] 2. The upgrade can be achieved without replacing the vehicle's original light and rain sensor and wiper actuator. Only the addition of a piezoelectric ceramic sensor and signal conditioning module and optimization of the vehicle body controller algorithm are required. The modification cost is low, it can be adapted to most vehicle models, and it is easy to promote on a large scale. The piezoelectric ceramic sensor has a detection frequency of 10-20Hz, which can quickly capture changes in precipitation. Together with the synchronously detected light and rain sensor, it ensures that the wipers respond to fluctuations in precipitation intensity in a timely manner, further ensuring driving safety. Attached Figure Description

[0018] Figure 1 This is a flowchart of the piezoelectric ceramic sensor signal processing and integral quantization process in a windshield wiper control method based on piezoelectric ceramics according to the present invention. Figure 2This is a flowchart of the light and rain sensor signal processing and precipitation integration in a windshield wiper control method based on piezoelectric ceramics according to the present invention. Figure 3 This is a flowchart of the total integral calculation and wiper state control in a wiper control method based on piezoelectric ceramics according to the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0021] A wiper control method based on piezoelectric ceramics, the steps of which are as follows: Since the windshield of a vehicle is located in a high-frequency area where rainwater naturally falls and impacts the windshield, it can capture the elastic waves generated when rainwater hits the windshield with the highest probability. Furthermore, the upper middle part of the windshield is less affected by the vehicle's own structure (such as the range of the windshield wipers and other components), which can reduce false triggering by non-rainwater factors (such as dust, foreign objects, and vehicle vibration) and improve detection reliability. Therefore, piezoelectric ceramic sensors are deployed in the area inside the windshield that is easily hit by rainwater.

[0022] Therefore, S1: Piezoelectric ceramic sensors are used to collect precipitation signals. The specific working principle of piezoelectric ceramic sensors is as follows: Piezoelectric ceramic sensors utilize the piezoelectric effect (working - when rain hits the windshield), which generates elastic waves. When the elastic waves are transmitted to the piezoelectric ceramic sensors, they cause slight deformation of their crystal structure, which in turn leads to the separation of positive and negative charges inside, generating electrical signals. Since the intensity of the electrical signal is directly related to the elastic wave (i.e., the force and frequency of rain impact), the electrical signal is processed by the signal conditioning module (filtering, amplification, A / D conversion) built into the piezoelectric ceramic sensor. The working principle of filtering electrical signals is as follows: Using a filtering circuit (such as an RC filter circuit or an active filter circuit), the impedance or conduction characteristics of capacitors and inductors to signals of different frequencies are utilized to filter out interference noise (usually high-frequency or non-target frequency signals) in the electrical signal, retaining the effective electrical signal corresponding to the elastic waves of rainwater. The specific calculation formula is as follows: ; in: This is the resistance value. This is the capacitance value. It is a complex frequency; It can effectively filter high-frequency signals in electrical signals while retaining the effective electrical signals corresponding to rainwater elastic waves; However, since the filtered electrical signal is usually quite weak, it cannot meet the requirements for subsequent A / D conversion, resulting in insufficient accuracy or inability to recognize the signal during A / D conversion. Therefore, the received filtered electrical signal is amplified by constructing an amplification circuit using an operational amplifier (such as an op-amp chip). Utilizing the high gain characteristic of the op-amp, the weak electrical signal is amplified by a certain proportion. The specific calculation formula for the operational amplifier is as follows: ; in: For feedback resistor, The input resistance is indicated by a negative sign, which means the output signal is out of phase with the input signal. It can amplify the filtered electrical signal by a certain proportion to meet the needs of subsequent A / D conversion; Since digital systems such as vehicle controllers only process digital signals, the specific working principle of acquiring, filtering, and amplifying continuous electrical signals, and converting them into digital signals, is as follows: Voltage range for receiving continuous voltage signals The number of bits in an analog-to-digital converter chip and analog voltage Calculate digital quantities The specific calculation expression is as follows: ; It can convert electrical signals into digital signals, which can be received by digital systems such as vehicle controllers to control the windshield wipers. This can effectively improve the accuracy of windshield wiper control and avoid misjudgment caused by external environmental factors. Then the intensity of rainwater elastic waves is calculated according to the corresponding digital signal. Divided into 5 intervals, each interval corresponds to a threshold level (defined as...). , , , The four threshold levels are determined based on the elastic wave intensity under simulated rainfall (light rain, moderate rain, heavy rain) and the statistical digital signal distribution range, and are assigned corresponding integral values ​​as follows: Extremely low threshold (integral = 0): The elastic wave is extremely weak, corresponding to a digital signal range of... ( (for the first-level threshold) Low threshold (integral=1): Weak elastic wave, corresponding to a digital signal range of... ( (for the second-level threshold); Threshold (integral=2): Medium for elastic waves, corresponding to the range of digital signals. ( (for the third-level threshold) High threshold (integral=3): Stronger elastic wave, corresponding to a digital signal range of... ( (for the fourth level threshold); Extremely high threshold (integral=4): strong elastic wave, corresponding to a digital signal range of... ( (The maximum digital value of the A / D conversion). Then the vehicle controller reads the digital signal after A / D conversion in real time and judges the digital signal. Which of the five intervals it falls into allows us to determine the corresponding threshold integral. The specific logical expression for determining the level is as follows: ; It can convert continuous elastic wave intensity into discrete 5-level integrals, providing a quantitative basis for subsequent wiper control. It can convert elastic wave intensity into 5 threshold integral levels (extremely low threshold, low threshold, medium threshold, high threshold, and extremely high threshold, corresponding to integrals 0-4), thereby reflecting whether precipitation actually exists and the intensity of its existence.

[0023] S2: Receives the detection results from the piezoelectric ceramic sensor and dynamically adjusts the trigger sensitivity of the wipers. The specific working principle is as follows: when the piezoelectric ceramic sensor detects an elastic wave, the threshold adjustment algorithm is used to automatically lower the wiper trigger threshold. If the sensor does not detect an elastic wave, the threshold adjustment algorithm is used to automatically raise the wiper trigger threshold. Set the lower limit of the original integral trigger for the windshield wipers in various operating states, specifically as follows: Low-speed scraping original trigger lower limit: ; Medium-speed scraping original trigger lower limit: ; High-speed scraping original trigger lower limit: ; If the piezoelectric ceramic sensor detects an elastic wave, the trigger lower limit, dynamically adjusted by the threshold adjustment algorithm, is: ; Where: the percentages in the expression are determined based on real vehicle tests (such as wiper performance under different rainfall levels and statistics on false trigger rates). For example: a 20% reduction can ensure that the wipers start in time during light rain, while a 50% increase can prevent false wiping when there is no rain. If the piezoelectric ceramic sensor does not detect the elastic wave, the trigger lower limit dynamically adjusted by the threshold adjustment algorithm is: ; It can dynamically adjust the trigger threshold of the windshield wipers in real time, which can ensure timely wiping during rainfall and avoid accidental wiping when there is no rain, thus effectively improving the accuracy of windshield wiper control. Furthermore, to avoid the impact of different vehicle speeds on the threshold, for example: low sensitivity is required when driving at high speeds to avoid accidental triggering by rain splashes, while high sensitivity is required when driving in low-speed congestion to allow for early wiping and other scenarios. Therefore, the core logic of establishing a correlation model between vehicle speed and threshold adjustment range is as follows: In low-speed congestion scenarios (vehicle speed ≤ 40km / h): the vehicle driving environment is complex, and precipitation is prone to accumulate on the windshield, so it is necessary to improve the sensitivity of the wipers to ensure that light precipitation is wiped away in time; Medium-speed driving scenario (40km / h < vehicle speed ≤ 80km / h): Under normal road conditions, maintain basic sensitivity and balance the timeliness of wiping with system stability; High-speed driving scenarios (vehicle speed > 80km / h): Rain splashes and airflow disturbances can easily cause sensor misjudgments. It is necessary to reduce the sensitivity of the wipers to avoid wiping when there is no rain or triggering the wipers due to slight splashes. The dynamically adjusted trigger lower limit expression is: ; in: To adjust the coefficient, based on vehicle speed The decision, specifically: like (High sensitivity ensures timely wiping even in low-speed congestion). like (Basic sensitivity, adapted to normal road conditions); like (Low sensitivity to avoid false triggering by high-speed splashing).

[0024] It enables the vehicle controller to read the vehicle speed signal in real time and dynamically correct the wiper trigger threshold, so that the wipers can accurately and realistically apply water at different vehicle speeds.

[0025] S3: Since the light rain sensor works based on the principle of light reflection / refraction, the working principle of the light rain sensor is as follows: The light rain sensor emits specific light (usually infrared light) towards the vehicle windshield. If there is no rain on the windshield surface, the light will be reflected or refracted along a preset path; if there is rain, the rain will change the propagation path of the light (change in reflection angle, change in refraction intensity), which will cause changes in the light intensity, phase and other characteristics at the sensor receiving end. At this point, the photoelectric conversion element inside the light rain sensor converts the received light signal into an electrical signal. The specific working principle is as follows: when specific light (such as infrared light) shines on the semiconductor PN junction of the photodiode, the photon energy is absorbed by electrons in the junction region, causing electrons to jump from the valence band to the conduction band, forming freely moving photogenerated carriers (electron-hole pairs). These carriers separate under the influence of the built-in electric field of the PN junction, forming a photogenerated voltage across the diode; if the external circuit is closed, a photogenerated current is generated. The specific calculation expression is as follows: ; in: For photoelectric conversion efficiency, Electron charge (fixed value) ), The incident light wavelength, Planck's constant (a fixed value) ), speed of light Incident light power, The light-receiving area of ​​a photodiode; Then sense the external load resistance of the diode. Calculating photoelectric voltage based on Ohm's law The specific calculation formula is as follows: ; The photoelectric voltage is then amplified and filtered, and converted into a digital signal via an A / D converter. The specific calculation expression is as follows: ; in: This is the minimum input voltage (e.g., 0V) for the A / D converter. This is the maximum input voltage of the A / D converter (e.g., 5V). The number of bits in the A / D converter. The quantized digital signal; This allows the changes in light to be converted into electrical signals, providing a valid basis for subsequent precipitation integral calculations; The electrical signal after photoelectric conversion is then quantized to obtain the change in light intensity. The specific working principle is as follows: Digital signals are mapped linearly. Converted into changes in light intensity The specific calculation expression is as follows: ; in: This is the proportionality coefficient. This is the offset; And set an interval threshold to determine the output precipitation integral. The interval threshold is set as follows: The specific decision logic expression is as follows: ; It can be used to calculate the total integral of wiper control in subsequent calculations.

[0026] S4: Receive threshold integral and precipitation integral Integrating the threshold Multiply by precipitation integral The total integral of the wiper control is obtained, and the specific expression is: ; It can be used to determine the working status of windshield wipers, effectively improving the accuracy of windshield wiper control; Then, a threshold range is set to determine the operating status command of the windshield wipers: When the total score is less than or equal to 1, it is determined that the current precipitation is extremely weak or there is no actual precipitation, the wipers are in the "no wiping" state, and the actuator stops working. When 1 < total score ≤ 5, it is judged as light precipitation, the wipers enter the "low speed wiping" mode, and the wiping interval is set to 8-10 seconds; When 5 < total score ≤ 10, it is judged as moderate precipitation, the wipers enter the "medium speed wiping" mode, and the wiping interval is set to 3-5 seconds; When the total score is greater than 10, it is determined to be heavy precipitation, and the windshield wipers enter "high-speed wiping" mode, wiping continuously without intervals. The specific determination expression is as follows: ; It can precisely control the working state of the windshield wipers based on the "presence" and "intensity" of actual precipitation, avoiding accidental wiping when there is no rain and ensuring timely wiping when it rains, effectively improving the accuracy of windshield wiper control.

[0027] S5: Combining variables such as vehicle dynamics (vehicle speed), meteorological conditions (rainfall level), and environmental interference (sudden changes in light, sensor contamination), a test matrix covering real-world driving scenarios is constructed to ensure that the control logic can work stably under various extreme or normal scenarios. For example, the "light rain + low speed" scenario simulates slight precipitation in congested urban traffic to verify the timeliness of low-speed wiping by the wipers; the "heavy rain + tunnel entrance / exit" scenario simulates heavy precipitation under sudden changes in light to verify the sensor's anti-interference capability and the speed of high-speed wiping. First, the number of times the wipers were falsely triggered under conditions of no rain or non-precipitation interference (such as dust or light) was measured, along with the total number of tests. The false trigger rate was then calculated using the following formula: ; It can detect the system's anti-interference capability; Then, the wiper activation time and the effective signal detection time of the piezoelectric ceramic sensor and the light rain sensor are sensed to calculate the wiper response time. The specific calculation expression is as follows: ; This ensures that the wipers work quickly after rainfall; Finally, the visual acuity score is calculated using a subjective rating method. The specific calculation formula is as follows: ; in: For the number of evaluators, the target score is ≥90 points, with a maximum score of 100 points. It can effectively reflect the clarity of the windshield's field of vision, enabling the wiper control scheme to form a closed loop from theoretical design to actual verification, thereby improving the rigor and feasibility of the scheme.

[0028] Furthermore, this invention also considers that if abnormal situations such as "false triggering during light rain at high speed" occur during real vehicle testing, it is necessary to analyze the test data (such as the signal output of piezoelectric ceramics and light rain sensors in high-speed scenarios, and the total integral calculation results) and adjust the adjustment range of the dynamic threshold (such as reducing the adjustment range from 10% to 5%) to make the wiper triggering logic more suitable for the real precipitation characteristics of the scenario. Therefore, the initial adjustment range is set as follows: The optimized adjustment range is The specific expression is: ; in: The adjustment coefficients are determined based on actual vehicle test data; To avoid signal failure of the piezoelectric ceramic sensor, if no valid signal is detected for 3 consecutive seconds (e.g., sensor hardware failure, circuit break), the piezoelectric ceramic sensor is considered to be faulty. Specifically: Setting the signal detection period of the piezoelectric ceramic sensor The number of consecutive times the wipers show no signal is: ; If at this time When the value is ≥30, it is determined that the sensor has failed and the mode switch is triggered. This can effectively prevent the wiper system from being completely paralyzed due to the failure of a single sensor and ensure basic wiping function.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A piezoceramic-based wiper control method, characterized by: The method steps are as follows: S1: Adopt piezoelectric ceramic sensor to collect precipitation signal, and convert precipitation signal into electric signal, pretreat electric signal, and output digital signal And threshold value is divided into threshold value grades, and integral is given to threshold value grades, and threshold value integral is obtained. S2: set the original integral trigger lower limit of the wiper in various working states, dynamically adjust the trigger lower limit through the threshold adjustment algorithm, and establish a correlation model of vehicle speed and threshold adjustment amplitude, and again dynamically adjust the trigger lower limit; S3: the light rain sensor converts the received light signal into an electric signal, calculates the photoelectric current as a photoelectric voltage, pre-processes the photoelectric voltage, and outputs a digital signal , calculates the light change amount, divides the threshold level, gives it an integral, and obtains the precipitation integral; S4: calculate the total integral of the wiper, set the interval threshold, and determine the working state instruction of the output wiper; S5: calculate the false trigger rate, response time, and calculate the visual field clarity score through the subjective scoring method, set the original adjustment amplitude, calculate the optimized adjustment amplitude and the continuous no-signal number of the wiper.

2. The piezoceramic-based wiper control method according to claim 1, characterized in that: The specific principle of converting the precipitation signal into an electrical signal in S1 is that the piezoelectric ceramic sensor utilizes the piezoelectric effect to generate an elastic wave, when the elastic wave is transmitted to the piezoelectric ceramic sensor, the crystal structure thereof is deformed slightly, thereby causing internal positive and negative charge separation and generating an electrical signal. The pre-processing electrical signal includes filtering, amplification, and converting the continuous electrical signal into a digital signal.

3. A piezoceramic-based wiper control method according to claim 2, characterized in that: The calculation expression of the electrical signal filtering is that the transfer function is equal to 1 divided by the product of the resistance value and the capacitance value multiplied by the complex frequency s, plus 1. The calculation expression of the electrical signal amplification is that the voltage amplification factor is equal to the resistance value of the feedback resistance divided by the resistance value of the input resistance, and the result is taken as a negative value. The calculation expression of the electrical signal conversion into a digital signal is that the analog voltage is subtracted from the minimum value of the voltage range, defined as a first value, and the difference between the maximum value and the minimum value of the voltage range is defined as a second value. The first value is divided by the second value, and then multiplied by 2 raised to the power of n.

4. A piezoceramic-based wiper control method according to claim 3, characterized in that: The logic of the threshold level is to divide the digital signal into 5 intervals, each interval corresponds to a threshold level and the threshold level is given a corresponding integral value to obtain the threshold integral.​​​​ 5. A piezoceramic-based wiper control method according to claim 4, characterized in that: The logic of the threshold adjustment algorithm dynamically adjusting the trigger lower limit is that when the piezoelectric ceramic sensor detects an elastic wave, the threshold adjustment algorithm is used to automatically lower the wiper trigger threshold, and if the sensor does not detect an elastic wave, the threshold adjustment algorithm is used to automatically raise the wiper trigger threshold. The calculation formula of the threshold adjustment algorithm is that the original trigger lower limit is multiplied by 1 minus the adjustment proportion. The logic of the trigger lower limit after the second dynamic adjustment is that the trigger lower limit after the adjustment of the threshold adjustment algorithm is multiplied by 1 minus the adjustment coefficient.

6. A piezoceramic-based wiper control method according to claim 5, characterized in that: The photo-generated current is equal to the photoelectric conversion efficiency multiplied by the electronic charge, multiplied by the ratio of the incident light wavelength to the product of the Planck constant and the speed of light, multiplied by the incident light power and the light receiving area of the photodiode, the photoelectric voltage is equal to the photo-generated current multiplied by the load resistance, the digital signal is equal to the photoelectric voltage minus the minimum value of the voltage range, defined as a first value, the difference between the maximum value of the voltage range minus the minimum value, defined as a second value, the first value divided by the second value, and finally multiplied by 2 raised to the power of n.

7. A piezoceramic-based wiper control method according to claim 6, characterized in that: The light ray variation quantity is equal to a proportional coefficient multiplied by a digital signal With the offset added, the determination logic of the precipitation integral is the same as the threshold integral determination.

8. A piezoceramic-based wiper control method according to claim 7, characterized in that: The total integral of the wiper is equal to the threshold integral multiplied by the precipitation integral, the interval threshold is set, the total integral is compared with the interval threshold, and the working state instruction of the output wiper is determined.

9. A piezoceramic-based wiper control method according to claim 8, characterized in that: The false trigger rate is equal to the false trigger number divided by the total test number multiplied by 100%. The wiper response time is equal to the wiper start time minus the time of the effective signal detected by the sensor. The visual field clarity score is equal to the sum of the scores of all evaluators divided by the number of evaluators.

10. A piezoceramic-based wiper control method according to claim 9, characterized in that: The adjustment amplitude is equal to the original adjustment amplitude multiplied by the adjustment coefficient. The continuous no-signal number is equal to the no-signal time minus the detection period.

Images