A photovoltaic panel stubborn stain local micro-liquid mist stripping cleaning method and system based on ultrasonic vibration

Abstract

This invention discloses a method and system for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration, relating to the field of photovoltaic power generation equipment cleaning and intelligent operation and maintenance technology. The method includes: acquiring contamination distribution information on the photovoltaic panel surface, identifying target contaminated areas, and determining the stain type and adhesion level; matching cleaning parameters according to the stain type and adhesion level; activating the target contaminated area with localized micro-liquid mist; performing ultrasonic vibration pre-cracking and main body stripping on the activated target contaminated area according to the cleaning parameters; simultaneously recovering the generated residue and trace residual liquid; verifying the cleaning effect; if the preset cleaning threshold is not reached, compensatory cleaning is performed; if the preset cleaning threshold is reached, the process moves to the next contaminated area until all contaminated areas are cleaned. This invention can efficiently remove stubborn stains, reduce liquid consumption, and improve the level of intelligent operation and maintenance.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation equipment cleaning and intelligent operation and maintenance technology, and in particular to a method and system for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration. Background Technology

[0002] During long-term service, photovoltaic modules accumulate contaminants such as dust, silt, bird droppings, tree sap, oil film, and salt crystals on their surfaces. Ordinary dust can be removed by blowing it away or simply rinsing; however, stubborn stains formed after exposure to high temperatures, rain, and repeated wet-dry cycles often adhere strongly to the photovoltaic glass surface, making them difficult to remove effectively with conventional cleaning methods.

[0003] In existing technologies, photovoltaic panel cleaning methods mainly include manual wiping, high-pressure water spraying, and mechanical brushing. While these methods can effectively clean general contamination, they generally suffer from low cleaning efficiency, high water consumption, high labor or equipment costs, easy surface wear, and potential secondary pollution when dealing with stubborn stains. In water-scarce areas or large-scale centralized photovoltaic power plants, traditional water-intensive cleaning methods cannot meet the requirements of water conservation, environmental protection, and intelligent operation and maintenance. Current related technologies suffer from low efficiency in removing stubborn stains, high liquid consumption, high risk of damage to the photovoltaic panel surface, and the risk of secondary pollution during the cleaning process.

[0004] Therefore, proposing a method and system for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration to solve the difficulties of existing technologies is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method and system for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration. This method can solve the technical problems of low removal efficiency of stubborn stains, large liquid consumption, easy damage to the surface of the components, and insufficient control of secondary pollution in the prior art. It can achieve efficient stripping of highly attached stains, significantly reduce liquid consumption, and improve the level of intelligent operation and maintenance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration includes: S1. Obtain information on the distribution of contaminants on the surface of photovoltaic panels, identify target contaminant areas, and determine the type and level of stains. S2. Match cleaning parameters according to the type and adhesion level of stains in the target contaminated area; S3. Activate the target contaminated area with localized micro-liquid mist; S4. Based on the matched cleaning parameters, perform ultrasonic vibration pre-cracking and main body peeling on the activated target contaminated area; S5. Simultaneously recover the residue and trace amounts of residual liquid generated during ultrasonic vibration pre-cracking and main body peeling. S6. Verify the cleaning effect. If the preset cleaning threshold is not reached, perform compensatory cleaning. If the preset cleaning threshold is reached, proceed to the next contaminated area until all contaminated areas are cleaned.

[0007] Optionally, in the above method, in S1, obtaining the surface contamination distribution information of the photovoltaic panel, identifying the target contamination area, and determining the stain type and adhesion level, specifically involves: Collect images, reflectivity information, and contour information of the photovoltaic panel surface; Based on image grayscale changes, color distribution, edge texture, morphological features, and surface reflectance attenuation, the location, area, thickness, and boundary features of the contaminated area are identified, thus determining the target contaminated area. To distinguish between ordinary dust and stubborn stains, stains are classified into: bird droppings, mud stains, oil film stains, resin stains, salt crystal stains, and complex stubborn stains. Based on the difficulty of cleaning stains on the surface of photovoltaic panels, the adhesion level is divided into four levels: Level 1, Level 2, Level 3, or Level 4. Level 1 includes: lightly adhered ordinary dust and oily film stains; Secondary stains include: moderately adhered mud stains and salt crystal stains; Level 3 includes: highly adherent bird droppings stains and tree sap stains; Level 4 includes: complex and stubborn stains.

[0008] Optionally, in the above method, in S2, cleaning parameters are matched according to the stain type and adhesion level of the target contaminated area, specifically as follows: Based on the type and adhesion level of the stain, the corresponding cleaning strategy is called from the preset parameter library; The cleaning strategy includes: ultrasonic frequency, ultrasonic amplitude, pulse duty cycle, single-point action time, cleaning head scanning speed, contact pressure or suspension gap, liquid mist spraying volume, liquid mist spraying duration, and recovery negative pressure intensity; ultrasonic frequency: 20 kHz to 120 kHz; ultrasonic amplitude: 5 μm to 80 μm; pulse duty cycle: 20% to 80%; single-point action time: 0.1 s to 10 s; cleaning head scanning speed: 5 mm / s to 300 mm / s; contact pressure: 0.2 N to 20 N; suspension gap: 0.1 mm to 2.0 mm; recovery negative pressure intensity: 1 kPa to 20 kPa. Level 1 corresponding cleaning strategy parameters: ultrasonic frequency 60~100 kHz, ultrasonic amplitude 5~15 μm, cleaning head scanning speed 100~300 mm / s, no liquid spraying or liquid spraying ≤0.03 mL / cm². Secondary cleaning strategy parameters: ultrasonic frequency 40–80 kHz, ultrasonic amplitude 10–30 μm, cleaning head scanning speed 50–150 mm / s, and spray liquid 0.03–0.08 mL / cm². The parameters for the Level 3 cleaning strategy are as follows: ultrasonic frequency 25–60 kHz, ultrasonic amplitude 25–60 μm, cleaning head scanning speed 10–80 mm / s, and liquid spray 0.08–0.20 mL / cm². Level 4 corresponding cleaning strategy parameters: ultrasonic frequency 20-50 kHz, ultrasonic amplitude 40-80 μm, cleaning head scanning speed 5-40 mm / s, spray liquid 0.15-0.30 mL / cm², and perform 2-3 compensation cleaning cycles.

[0009] Optionally, in the above method, in step S3, localized micro-liquid mist activation is performed on the target contaminated area, specifically as follows: Only short-term atomized spraying is applied to the edge areas of stains, the core areas of thick stains, or pre-cracked areas; the entire photovoltaic panel is not continuously rinsed. The pre-cracked area is the boundary zone extending 0–5 mm inward and 0–3 mm outward along the outer contour of the stain, or the core area of ​​a thick stain with a thickness greater than 0.2 mm and a reflectivity attenuation greater than 25%. The distance between the liquid mist nozzle and the panel surface is 5 mm to 30 mm, the spray angle is 15° to 60°, and the local spray coverage area is 10% to 60% of the target stain area; The spraying time is 0.1 s to 2 s before ultrasonic edge pre-cracking or during the pre-cracking process.

[0010] Optionally, in the above method, in S4, ultrasonic vibration pre-cracking and main body peeling are performed on the activated target contaminated area according to the matched cleaning parameters, specifically as follows: After the cleaning head is in place, the ultrasonic transducer drives the vibrating cleaning head to first apply short-time pulsed ultrasonic action to the edge area of ​​the stain, causing the stain layer to form initial cracks, edge lifting, or local detachment. After pre-cracking is completed, the cleaning head is controlled to continuously or intermittently scan the main area of ​​the stain along the preset path, causing the stain to loosen in the middle, detach as a whole, and break off. During ultrasonic vibration, the amplitude, duty cycle, and scanning speed are dynamically adjusted based on real-time feedback. Real-time feedback includes: contact force F, glass surface temperature rise ΔT, vibration power / current change, reflectivity recovery rate R, residual stain area A_r, and cleaning head displacement response; Real-time feedback parameter thresholds: Contact force F≤10 N, safety limit 20 N; Surface temperature rise ΔT ≤ 10 ℃, or plate surface temperature ≤ 60℃; If the vibration power / current change exceeds 30% of the reference value, it is determined to be an abnormal contact or blockage by hard particles; If the residual area A_r > 3%, proceed with compensation cleaning; If the threshold is exceeded, reduce the amplitude by 20% to 40%, increase the scanning speed by 10% to 30%, pause for 5 to 10 seconds, or switch to a low-energy mode.

[0011] Optionally, in the above method, in step S5, the residue and trace amounts of residual liquid generated during ultrasonic vibration pre-cracking and main body peeling are simultaneously recovered, specifically as follows: A negative pressure recovery device is installed behind or around the vibrating cleaning head to simultaneously recover the stripped contaminants and recover the detached dirt particles, powder, mud, crystal fragments and trace amounts of residual liquid. The negative pressure recovery device includes: a negative pressure adsorption port, a flow guide hood, a filter unit, a gas-liquid separation unit, and a collection container.

[0012] Optionally, in step S6 of the above method, the cleaning effect is reviewed. If the preset cleaning threshold is not reached, compensatory cleaning is performed. If the preset cleaning threshold is reached, the process moves to the next contaminated area until all contaminated areas are cleaned. Specifically: The cleaned area was re-inspected to obtain indicators such as the degree of reflectivity recovery, the area of ​​residual stains, and the surface uniformity. Preset cleaning thresholds include: Reflectance recovery rate ≥90%; The area of ​​residual stains is ≤5% of the target area; The surface uniformity index is defined as a grayscale / reflectivity coefficient of variation (CV) ≤ 10%; When the cleaning effect reaches the preset cleaning threshold, the current area operation ends and the next target area is cleaned. When the cleaning effect does not reach the preset cleaning threshold, the cleaning parameters are called again to perform secondary processing, and the movement path is optimized according to the stain distribution density. Re-execute the secondary processing parameter adjustment rules by re-invoking the cleaning parameters: If the residual stain area is 3% to 10%, increase the single-point action time by 10% to 30% or the duty cycle by 10% to 20%. If the residual stain area is >10%, within the safety threshold, increase the amplitude by 10% to 30% and add 0.01 to 0.05 mL / cm² liquid mist; If the standard is not met after three consecutive compensation attempts, it will be marked as a manual review / high-risk stain. If the contact force or temperature rise exceeds the threshold, the amplitude should not be increased further; instead, the scanning speed should be reduced or the process should be performed in multiple segments.

[0013] A localized micro-liquid mist stripping and cleaning system for stubborn stains on photovoltaic panels based on ultrasonic vibration, comprising performing any one of the above-described methods for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration, including: The stain detection and identification module is used to obtain information on the distribution of contaminants on the surface of photovoltaic panels and to identify the type, area, thickness, boundary features, and adhesion level of stains. The control module, connected to the stain detection and identification module, is used to coordinate and control the various modules in a unified manner. Based on the stain distribution and category information, it outputs the ultrasonic frequency, amplitude, duty cycle, contact pressure, scanning speed, liquid mist spraying volume, spraying timing, and recovery power. The mobile execution module, connected to the control module, is used to drive the cleaning device to move along the surface of the photovoltaic panel or along the direction of the module array according to the output parameters of the control module, so as to achieve the positioning, scanning and continuous operation of the target stain area; The micro-liquid mist supply module, connected to the control module, is used to apply liquid mist locally, quantitatively, and for a short time to areas with stubborn stains. The ultrasonic vibration cleaning module, connected to the control module, is used to apply ultrasonic mechanical vibration to the target contaminated area to achieve stain debonding, pyrolysis and peeling. The pressure and attitude adjustment module, connected to the control module, is used to adjust the relative attitude, contact angle, suspension distance, or contact pressure between the ultrasonic vibration cleaning module and the photovoltaic panel surface. The residue synchronous recovery module is connected to the control module and is used to recover particles, mud, crystal fragments and trace amounts of residual liquid after the stains are removed. The power supply and safety protection module, connected to the control module, is used to supply power to the system and protect against overcurrent, overvoltage, overheating, abnormal contact, and abnormal collision.

[0014] As can be seen from the above technical solution, compared with the prior art, the present invention provides a method and system for localized micro-liquid mist peeling and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration, which has the following beneficial effects: the mechanical stress generated by ultrasonic vibration can effectively destroy the adhesion interface between stubborn stains and the photovoltaic glass surface, achieving rapid and thorough peeling, especially suitable for highly adhesive stains such as bird droppings, tree sap, and mud stains; micro-liquid mist is sprayed only in localized areas of the stain for activation and stress coupling, avoiding the large water consumption of traditional high-pressure water washing or rinsing methods, resulting in significant water saving; the use of non-contact or low-contact pressure ultrasonic vibration, combined with pressure and attitude adjustment modules, avoids surface scratches or wear that may be caused by mechanical brushing; the peeled stain particles and micro-liquid residues are recovered immediately to prevent contaminants from spreading or flowing into the cleaned area; and the system integrates stain recognition, parameter adaptive matching, effect feedback, and path optimization functions, realizing fully automated closed-loop control from detection and cleaning to verification. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 A flowchart of a method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration, provided by the present invention; Figure 2 The present invention provides a structural diagram of a localized micro-liquid mist stripping and cleaning system for stubborn stains on photovoltaic panels based on ultrasonic vibration. Detailed Implementation

[0017] 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, 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.

[0018] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0019] Reference Figure 1 As shown, this invention discloses a method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration, comprising: S1. Obtain information on the distribution of contaminants on the surface of photovoltaic panels, identify target contaminant areas, and determine the type and level of stains. S2. Match cleaning parameters according to the type and adhesion level of stains in the target contaminated area; S3. Activate the target contaminated area with localized micro-liquid mist; S4. Based on the matched cleaning parameters, perform ultrasonic vibration pre-cracking and main body peeling on the activated target contaminated area; S5. Simultaneously recover the residue and trace amounts of residual liquid generated during ultrasonic vibration pre-cracking and main body peeling. S6. Verify the cleaning effect. If the preset cleaning threshold is not reached, perform compensatory cleaning. If the preset cleaning threshold is reached, proceed to the next contaminated area until all contaminated areas are cleaned.

[0020] Furthermore, in S1, information on the distribution of contaminants on the photovoltaic panel surface is obtained, target contaminated areas are identified, and the type and adhesion level of the stains are determined, specifically: Collect images, reflectivity information, and contour information of the photovoltaic panel surface; Based on image grayscale changes, color distribution, edge texture, morphological features, and surface reflectance attenuation, the location, area, thickness, and boundary features of the contaminated area are identified, thus determining the target contaminated area. To distinguish between ordinary dust and stubborn stains, stains are classified into: bird droppings, mud stains, oil film stains, resin stains, salt crystal stains, and complex stubborn stains. Based on the difficulty of cleaning stains on the surface of photovoltaic panels, the adhesion level is divided into four levels: Level 1, Level 2, Level 3, or Level 4. Level 1 includes: lightly adhered ordinary dust and oily film stains; Secondary stains include: moderately adhered mud stains and salt crystal stains; Level 3 includes: highly adherent bird droppings stains and tree sap stains; Level 4 includes: complex and stubborn stains.

[0021] Furthermore, in S2, cleaning parameters are matched according to the type and adhesion level of the stains in the target contaminated area, specifically: Based on the type and adhesion level of the stain, the corresponding cleaning strategy is called from the preset parameter library; The cleaning strategy includes: ultrasonic frequency, ultrasonic amplitude, pulse duty cycle, single-point action time, cleaning head scanning speed, contact pressure or suspension gap, liquid mist spraying volume, liquid mist spraying duration, and recovery negative pressure intensity; ultrasonic frequency: 20 kHz to 120 kHz, preferably 25 kHz to 60 kHz; ultrasonic amplitude: 5 μm to 80 μm, preferably 15 μm to 50 μm; pulse duty cycle: 20% to 80%, preferably 35% to 65%; single-point action time: 0.1 s to 10 s, preferably 0.5 s to 5 s; cleaning head scanning speed: 5 mm / s to 300 mm / s, preferably 10 mm / s to 80 mm / s for stubborn stains; contact pressure: 0.2 N to 20 N, preferably 1 N to 8 N; suspension gap: 0.1 mm to 2.0 mm; recovery negative pressure intensity: 1 kPa to 20 kPa, preferably 5 kPa to 12 kPa. Level 1 corresponding cleaning strategy parameters: ultrasonic frequency 60~100 kHz, ultrasonic amplitude 5~15 μm, cleaning head scanning speed 100~300 mm / s, no liquid spraying or liquid spraying ≤0.03 mL / cm². Secondary cleaning strategy parameters: ultrasonic frequency 40–80 kHz, ultrasonic amplitude 10–30 μm, cleaning head scanning speed 50–150 mm / s, and spray liquid 0.03–0.08 mL / cm². The parameters for the Level 3 cleaning strategy are as follows: ultrasonic frequency 25–60 kHz, ultrasonic amplitude 25–60 μm, cleaning head scanning speed 10–80 mm / s, and liquid spray 0.08–0.20 mL / cm². Level 4 corresponding cleaning strategy parameters: ultrasonic frequency 20-50 kHz, ultrasonic amplitude 40-80 μm, cleaning head scanning speed 5-40 mm / s, spray liquid 0.15-0.30 mL / cm², and perform 2-3 compensation cleaning cycles.

[0022] Furthermore, in S3, localized micro-liquid mist activation is performed on the target contaminated area, specifically as follows: Short-term atomized spraying is applied only to the edge area of ​​the stain, the core area of ​​the thick stain, or the pre-cracked area, without continuous rinsing of the entire photovoltaic panel; the liquid is preferably deionized water, but can also be a low-concentration surface tension regulating liquid, a weakly polar wetting agent, or a volatile low-residue cleaning liquid, to reduce the local adhesion strength of the stain, improve the coupling effect of ultrasonic vibration on stress transmission, promote the initiation and propagation of internal cracks in the stain, and avoid liquid waste and secondary pollution caused by rinsing the entire panel; The pre-cracked area can be defined as the boundary zone extending 0–5 mm inward and 0–3 mm outward along the outer contour of the stain, or the core area of ​​a thick stain with a thickness greater than 0.2 mm and a reflectivity attenuation greater than 25%. The distance between the liquid mist nozzle and the panel surface can be 5 mm to 30 mm, the spray angle can be 15° to 60°, and the local spray coverage area can be 10% to 60% of the target stain area, preferably 20% to 40%. The spraying time is 0.1 s to 2 s before ultrasonic edge pre-cracking or during the pre-cracking process.

[0023] Furthermore, in S4, based on the matched cleaning parameters, ultrasonic vibration pre-cracking and main body peeling are performed on the activated target contaminated area, specifically as follows: After the cleaning head is in place, the ultrasonic transducer drives the vibrating cleaning head to first apply short-time pulsed ultrasonic action to the edge area of ​​the stain, causing the stain layer to form initial cracks, edge lifting, or local detachment. After pre-cracking is completed, the cleaning head is controlled to continuously or intermittently scan the main area of ​​the stain along the preset path, causing the stain to loosen in the middle, detach as a whole, and break off. During ultrasonic vibration, the amplitude, duty cycle, and scanning speed are dynamically adjusted based on real-time feedback. Real-time feedback includes: contact force F, glass surface temperature rise ΔT, vibration power / current change, reflectivity recovery rate R, residual stain area A_r, and cleaning head displacement response; Real-time feedback parameter thresholds: Contact force F≤10 N, safety limit 20 N; Surface temperature rise ΔT ≤ 10 ℃, or plate surface temperature ≤ 60℃; If the vibration power / current change exceeds 30% of the reference value, it is determined to be an abnormal contact or blockage by hard particles; If the residual area A_r > 3%, proceed with compensation cleaning; When the threshold is exceeded, the amplitude can be reduced by 20% to 40%, the scanning speed can be increased by 10% to 30%, the scan can be paused for 5 to 10 seconds, or the low-energy mode can be switched.

[0024] Furthermore, in S5, the residue and trace amounts of residual liquid generated during ultrasonic vibration pre-cracking and main body peeling are simultaneously recovered, specifically as follows: A negative pressure recovery device is installed behind or around the vibrating cleaning head to simultaneously recover the stripped contaminants and recover the detached dirt particles, powder, mud, crystal fragments and trace amounts of residual liquid. The negative pressure recovery device includes: a negative pressure adsorption port, a flow guide hood, a filter unit, a gas-liquid separation unit, and a collection container; The negative pressure adsorption port is preferably located behind or around the vibrating cleaning head, so that the stripped dirt particles can be sucked away immediately. A primary particle filter and a secondary gas-liquid separator are set in the adsorption channel to reduce the risk of clogging and prevent dirt from spreading or flowing to adjacent areas again.

[0025] Furthermore, in S6, the cleaning effect is reviewed. If the preset cleaning threshold is not met, compensatory cleaning is performed. If the preset cleaning threshold is met, the process moves to the next contaminated area until all contaminated areas are cleaned. Specifically: The cleaned area was re-inspected to obtain indicators such as the degree of reflectivity recovery, the area of ​​residual stains, and the surface uniformity. Preset cleaning thresholds include: Reflectance recovery rate ≥90%, preferably ≥95%; The area of ​​residual stains should be ≤5% of the target area, preferably ≤3%; The surface uniformity index is defined as a grayscale / reflectivity coefficient of variation (CV) ≤ 10%; When the cleaning effect reaches the preset cleaning threshold, the current area operation ends and the next target area is cleaned. When the cleaning effect does not reach the preset cleaning threshold, the cleaning parameters are called again to perform secondary processing, and the movement path is optimized according to the stain distribution density. Re-execute the secondary processing parameter adjustment rules by re-invoking the cleaning parameters: If the residual stain area is 3% to 10%, increase the single-point action time by 10% to 30% or the duty cycle by 10% to 20%. If the residual stain area is >10%, within the safety threshold, increase the amplitude by 10% to 30% and add 0.01 to 0.05 mL / cm² liquid mist; If the standard is not met after three consecutive compensation attempts, it will be marked as a manual review / high-risk stain. If the contact force or temperature rise exceeds the threshold, the amplitude should not be increased further; instead, the scanning speed should be reduced or the process should be performed in multiple segments.

[0026] Furthermore, the method follows a graded cleaning logic of starting with light stains and moving to heavy stains, starting with the edges and moving to the center, starting with pre-cracking and moving to peeling, and starting with recycling and moving to verification. For light stains, low-energy ultrasonic scanning is performed directly. For heavily adhered stains, local liquid mist activation and edge pre-cracking are performed first, followed by the main body peeling. The method also includes adaptive parameter correction logic, which automatically increases the local vibration time, increases the pulse duty cycle, or increases the liquid mist spraying volume when the residual stain area after cleaning is still higher than the threshold; and automatically reduces the amplitude, pauses cleaning, or switches to a low-energy mode when the temperature rise of the glass surface or the contact force exceeds the safety threshold.

[0027] Reference Figure 2 As shown, a localized micro-liquid mist stripping and cleaning system for stubborn stains on photovoltaic panels based on ultrasonic vibration is implemented, comprising the following steps: The stain detection and recognition module is used to acquire information on the distribution of contaminants on the surface of photovoltaic panels and to identify the type, area, thickness, boundary features, and adhesion level of stains. The stain detection and recognition module includes one or more of the following: a visible light camera, a near-infrared imaging unit, a surface reflectivity detection unit, a macro vision unit, and a laser contour scanning unit. The control module, connected to the stain detection and identification module, is used to coordinate and control the various modules in a unified manner. Based on the stain distribution and category information, it outputs the ultrasonic frequency, amplitude, duty cycle, contact pressure, scanning speed, liquid mist spraying volume, spraying timing, and recovery power. The mobile execution module, connected to the control module, is used to drive the cleaning device to move along the surface of the photovoltaic panel or along the direction of the module array according to the output parameters of the control module, so as to achieve the positioning, scanning and continuous operation of the target stain area; The micro-liquid mist supply module, connected to the control module, is used to apply liquid mist locally, quantitatively, and for a short time to areas with stubborn stains. An ultrasonic vibration cleaning module, connected to a control module, is used to apply ultrasonic mechanical vibration to the target contaminated area to achieve stain removal, pyrolysis, and peeling. The ultrasonic vibration cleaning module includes: an ultrasonic transducer, a vibration amplification rod or vibration transmission rod, a vibration cleaning head, a compliant coupling layer, and a loading mechanism. The pressure and attitude adjustment module, connected to the control module, is used to adjust the relative attitude, contact angle, suspension distance, or contact pressure between the ultrasonic vibration cleaning module and the photovoltaic panel surface. The residue synchronous recovery module is connected to the control module and is used to recover particles, mud, crystal fragments and trace amounts of residual liquid after the stains are removed. The power supply and safety protection module, connected to the control module, is used to supply power to the system and protect against overcurrent, overvoltage, overheating, abnormal contact, and abnormal collision.

[0028] In one specific embodiment, for bird droppings hardened stains formed under sunny and high-temperature conditions, the control module identifies them as highly adherent and stubborn stains based on image features, and invokes a cleaning strategy of edge-priority activation, high-amplitude local dwell, and low-speed scanning; the micro-liquid mist supply module first performs a ring spray on the edge of the stain, then the ultrasonic vibration cleaning module performs pulsed pre-splitting and reciprocating scanning, the residue synchronous recovery module immediately sucks up debris and residual liquid, and finally the stain detection and identification module re-inspects the cleaned area and performs compensatory cleaning if necessary.

[0029] In another specific embodiment, for mud stains on the surface of photovoltaic panels in windy and sandy areas, the system adopts a strategy of multi-point liquid mist activation, sequential formation of multiple edge pre-crack points, and continuous low-speed scanning in the middle to gradually loosen, break, and remove thick mud blocks, thereby avoiding surface damage caused by repeated friction from traditional brushes.

[0030] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0031] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for ultrasonic vibration-based local micro-liquid fog stripping cleaning of stubborn stains on photovoltaic panels, characterized in that, include: S1. Obtain information on the distribution of contaminants on the surface of photovoltaic panels, identify target contaminant areas, and determine the type and level of stains. S2. Match cleaning parameters according to the type and adhesion level of stains in the target contaminated area; S3. Activate the target contaminated area with localized micro-liquid mist; S4. Based on the matched cleaning parameters, perform ultrasonic vibration pre-cracking and main body peeling on the activated target contaminated area; S5. Simultaneously recover the residue and trace amounts of residual liquid generated during ultrasonic vibration pre-cracking and main body peeling. S6. Verify the cleaning effect. If the preset cleaning threshold is not reached, perform compensatory cleaning. If the preset cleaning threshold is reached, proceed to the next contaminated area until all contaminated areas are cleaned.

2. The method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration according to claim 1, characterized in that, In S1, information on the distribution of contaminants on the photovoltaic panel surface is obtained, target contaminant areas are identified, and the type and adhesion level of the stains are determined. Specifically: Collect images, reflectivity information, and contour information of the photovoltaic panel surface; Based on image grayscale changes, color distribution, edge texture, morphological features, and surface reflectance attenuation, the location, area, thickness, and boundary features of the contaminated area are identified, thus determining the target contaminated area. To distinguish between ordinary dust and stubborn stains, stains are classified into: bird droppings, mud stains, oil film stains, resin stains, salt crystal stains, and complex stubborn stains. Based on the difficulty of cleaning stains on the surface of photovoltaic panels, the adhesion level is divided into four levels: Level 1, Level 2, Level 3, or Level 4. Level 1 includes: lightly adhered ordinary dust and oily film stains; Secondary stains include: moderately adhered mud stains and salt crystal stains; Level 3 includes: highly adherent bird droppings stains and tree sap stains; Level 4 includes: complex and stubborn stains.

3. The method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration according to claim 2, characterized in that, In S2, cleaning parameters are matched according to the type and adhesion level of the stains in the target contaminated area, specifically: Based on the type and adhesion level of the stain, the corresponding cleaning strategy is called from the preset parameter library; The cleaning strategy includes: ultrasonic frequency, ultrasonic amplitude, pulse duty cycle, single-point action time, cleaning head scanning speed, contact pressure or suspension gap, liquid mist spraying volume, liquid mist spraying duration, and recovery negative pressure intensity; ultrasonic frequency: 20 kHz to 120 kHz; ultrasonic amplitude: 5 μm to 80 μm; pulse duty cycle: 20% to 80%; single-point action time: 0.1 s to 10 s; cleaning head scanning speed: 5 mm / s to 300 mm / s; contact pressure: 0.2 N to 20 N; suspension gap: 0.1 mm to 2.0 mm; recovery negative pressure intensity: 1 kPa to 20 kPa. Level 1 corresponding cleaning strategy parameters: ultrasonic frequency 60~100 kHz, ultrasonic amplitude 5~15 μm, cleaning head scanning speed 100~300 mm / s, no liquid spraying or liquid spraying ≤0.03 mL / cm². Secondary cleaning strategy parameters: ultrasonic frequency 40–80 kHz, ultrasonic amplitude 10–30 μm, cleaning head scanning speed 50–150 mm / s, and spray liquid 0.03–0.08 mL / cm². The parameters for the Level 3 cleaning strategy are as follows: ultrasonic frequency 25–60 kHz, ultrasonic amplitude 25–60 μm, cleaning head scanning speed 10–80 mm / s, and liquid spray 0.08–0.20 mL / cm². Level 4 corresponding cleaning strategy parameters: ultrasonic frequency 20-50 kHz, ultrasonic amplitude 40-80 μm, cleaning head scanning speed 5-40 mm / s, spray liquid 0.15-0.30 mL / cm², and perform 2-3 compensation cleaning cycles.

4. The method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration according to claim 3, characterized in that, In S3, localized micro-liquid mist activation is performed on the target contaminated area, specifically as follows: Only short-term atomized spraying is applied to the edge areas of stains, the core areas of thick stains, or pre-cracked areas; the entire photovoltaic panel is not continuously rinsed. The pre-cracked area is the boundary zone extending 0–5 mm inward and 0–3 mm outward along the outer contour of the stain, or the core area of ​​a thick stain with a thickness greater than 0.2 mm and a reflectivity attenuation greater than 25%. The distance between the liquid mist nozzle and the panel surface is 5 mm to 30 mm, the spray angle is 15° to 60°, and the local spray coverage area is 10% to 60% of the target stain area; The spraying time is 0.1 s to 2 s before ultrasonic edge pre-cracking or during the pre-cracking process.

5. The method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration according to claim 4, characterized in that, In S4, based on the matched cleaning parameters, ultrasonic vibration pre-cracking and main body peeling are performed on the activated target contaminated area, specifically as follows: After the cleaning head is in place, the ultrasonic transducer drives the vibrating cleaning head to first apply short-time pulsed ultrasonic action to the edge area of ​​the stain, causing the stain layer to form initial cracks, edge lifting, or local detachment. After pre-cracking is completed, the cleaning head is controlled to continuously or intermittently scan the main area of ​​the stain along the preset path, causing the stain to loosen in the middle, detach as a whole, and break off. During ultrasonic vibration, the amplitude, duty cycle, and scanning speed are dynamically adjusted based on real-time feedback. Real-time feedback includes: contact force F, glass surface temperature rise ΔT, vibration power / current change, reflectivity recovery rate R, residual stain area A_r, and cleaning head displacement response; Real-time feedback parameter thresholds: Contact force F≤10 N, safety limit 20 N; Surface temperature rise ΔT ≤ 10 ℃, or plate surface temperature ≤ 60℃; If the vibration power / current change exceeds 30% of the reference value, it is determined to be an abnormal contact or blockage by hard particles; If the residual area A_r > 3%, proceed with compensation cleaning; If the threshold is exceeded, reduce the amplitude by 20% to 40%, increase the scanning speed by 10% to 30%, pause for 5 to 10 seconds, or switch to a low-energy mode.

6. The method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration according to claim 5, characterized in that, In S5, the residue and trace amounts of residual liquid generated during ultrasonic vibration pre-cracking and main body peeling are simultaneously recovered, specifically as follows: A negative pressure recovery device is installed behind or around the vibrating cleaning head to simultaneously recover the stripped contaminants and recover the detached dirt particles, powder, mud, crystal fragments and trace amounts of residual liquid. The negative pressure recovery device includes: a negative pressure adsorption port, a flow guide hood, a filter unit, a gas-liquid separation unit, and a collection container.

7. The method for localized micro-liquid mist stripping and cleaning of stubborn stains on photovoltaic panels based on ultrasonic vibration according to claim 6, characterized in that, In S6, the cleaning effect is reviewed. If the preset cleaning threshold is not met, compensatory cleaning is performed. If the preset cleaning threshold is met, the process moves to the next contaminated area until all contaminated areas are cleaned. Specifically: The cleaned area was re-inspected to obtain indicators such as the degree of reflectivity recovery, the area of ​​residual stains, and the surface uniformity. Preset cleaning thresholds include: Reflectance recovery rate ≥90%; The area of ​​residual stains is ≤5% of the target area; The surface uniformity index is defined as a grayscale / reflectivity coefficient of variation (CV) ≤ 10%; When the cleaning effect reaches the preset cleaning threshold, the current area operation ends and the next target area is cleaned. When the cleaning effect does not reach the preset cleaning threshold, the cleaning parameters are called again to perform secondary processing, and the movement path is optimized according to the stain distribution density. Re-execute the secondary processing parameter adjustment rules by re-invoking the cleaning parameters: If the residual stain area is 3% to 10%, increase the single-point action time by 10% to 30% or the duty cycle by 10% to 20%. If the residual stain area is >10%, within the safety threshold, increase the amplitude by 10% to 30% and add 0.01 to 0.05 mL / cm² liquid mist. If the standard is not met after three consecutive compensation attempts, it will be marked as a manual review / high-risk stain. If the contact force or temperature rise exceeds the threshold, the amplitude should not be increased further; instead, the scanning speed should be reduced or the process should be performed in multiple segments.

8. A ultrasonic vibration based local micro-liquid fog stripping cleaning system for stubborn stains on photovoltaic panels, performing a ultrasonic vibration based local micro-liquid fog stripping cleaning method for stubborn stains on photovoltaic panels according to any one of claims 1-7, characterized in that, include: The stain detection and identification module is used to obtain information on the distribution of contaminants on the surface of photovoltaic panels and to identify the type, area, thickness, boundary features, and adhesion level of stains. The control module, connected to the stain detection and identification module, is used to coordinate and control the various modules in a unified manner. Based on the stain distribution and category information, it outputs the ultrasonic frequency, amplitude, duty cycle, contact pressure, scanning speed, liquid mist spraying volume, spraying timing, and recovery power. The mobile execution module, connected to the control module, is used to drive the cleaning device to move along the surface of the photovoltaic panel or along the direction of the module array according to the output parameters of the control module, so as to achieve the positioning, scanning and continuous operation of the target stain area; The micro-liquid mist supply module, connected to the control module, is used to apply liquid mist locally, quantitatively, and for a short time to areas with stubborn stains. The ultrasonic vibration cleaning module, connected to the control module, is used to apply ultrasonic mechanical vibration to the target contaminated area to achieve stain debonding, pyrolysis and peeling. The pressure and attitude adjustment module, connected to the control module, is used to adjust the relative attitude, contact angle, suspension distance, or contact pressure between the ultrasonic vibration cleaning module and the photovoltaic panel surface. The residue synchronous recovery module is connected to the control module and is used to recover particles, mud, crystal fragments and trace amounts of residual liquid after the stains are removed. The power supply and safety protection module, connected to the control module, is used to supply power to the system and protect against overcurrent, overvoltage, overheating, abnormal contact, and abnormal collision.

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