An unmanned aerial vehicle and a control method for cleaning photovoltaic panels based on the unmanned aerial vehicle

Abstract

The application discloses a kind of unmanned plane and the control method based on unmanned plane cleaning photovoltaic board, unmanned plane includes fuselage, folding arm and support, fuselage is rotatably connected with one end of folding arm, the end of folding arm away from fuselage is rotatably connected with support, support is provided with spray head, control method includes: obtaining the position information of the existence of photovoltaic board attachment;According to position information, the flight height of unmanned plane is adjusted;Obtain the inclination angle of photovoltaic board and horizontal plane;According to inclination angle, the folding arm of unmanned plane is controlled to be unfolded, so that support is parallel to photovoltaic board, and spray head faces the light-receiving surface of photovoltaic board;Control spray head to open to clean photovoltaic board.The application is by making spray head face photovoltaic board attachment, improve the efficiency of cleaning photovoltaic board, while photovoltaic board can be cleaned more cleanly.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photovoltaic power stations, and particularly relates to a UAV and a control method for cleaning photovoltaic panels based on a UAV. BACKGROUND

[0002] With the popularization of photovoltaic power generation, the cleaning problem of photovoltaic panels is increasingly prominent, because dust, bird droppings, leaves and other pollutants can reduce the power generation efficiency of photovoltaic panels. The UAV cleaning of photovoltaic panels is a new technical solution, which is mainly used for the maintenance and cleaning of large-scale photovoltaic power stations. At present, the cleaning range of the UAV in the operation process is limited, and the cleaning is not thorough, and uneven removal of floating dust and scale on the photovoltaic panels occurs. SUMMARY

[0003] The application provides a UAV and a control method for cleaning photovoltaic panels based on a UAV, which solves the problem of insufficient cleaning of the UAV in the cleaning operation process and uneven removal of floating dust and scale on the photovoltaic panels.

[0004] In a first aspect, the application provides a control method for cleaning photovoltaic panels based on a UAV, the UAV comprising a fuselage, a folding arm and a support, the fuselage being rotationally connected to one end of the folding arm, the other end of the folding arm being rotationally connected to the support, the support being provided with a spray head, and the control method comprising:

[0005] obtaining the inclination angle of the photovoltaic panel and the horizontal plane;

[0006] obtaining the position information of the attached objects on the photovoltaic panel;

[0007] adjusting the flight position of the UAV according to the position information;

[0008] controlling the folding arm of the UAV to be unfolded according to the inclination angle, so that the support is parallel to the photovoltaic panel, and the spray head faces the attached objects in the photovoltaic panel;

[0009] controlling the spray head to be turned on to clean the attached objects in the photovoltaic panel.

[0010] In a feasible implementation, obtaining the position information of the attached objects on the photovoltaic panel comprises:

[0011] receiving a position signal of the photovoltaic panel and flying above the photovoltaic panel according to the position signal;

[0012] taking a photo of the photovoltaic panel to obtain an image;

[0013] analyzing the image to determine the position information of the attached objects on the photovoltaic panel.

[0014] In an implementation, the unmanned aerial vehicle further comprises a rotor, a rotation shaft of the rotor being hinged to the fuselage; adjusting the flight position of the unmanned aerial vehicle according to the position information comprises:

[0015] determining the height of the attached object based on the position information;

[0016] determining the flight position of the unmanned aerial vehicle based on the height of the attached object, the tilt angle of the photovoltaic panel and the horizontal plane, and the preset spraying distance of the spray head.

[0017] In an implementation, the folding arm of the unmanned aerial vehicle is controlled to be unfolded according to the tilt angle, so that the support is parallel to the photovoltaic panel, which comprises:

[0018] obtaining a current included angle between the support and the horizontal plane;

[0019] controlling the folding arm to be unfolded according to the current included angle between the support and the horizontal plane and the tilt angle;

[0020] controlling the support to rotate relative to the folding arm until the included angle between the support and the horizontal plane and the tilt angle are complementary angles.

[0021] In an implementation, the unmanned aerial vehicle is controlled to hover when the spray head is controlled to be turned on to clean the photovoltaic panel, which comprises:

[0022] obtaining a wind direction and a wind force of an external wind;

[0023] adjusting the rotation of the rotation shaft relative to the fuselage and the rotation speed of the rotor according to the wind direction and the wind force of the external wind, so that the wind force generated by the rotor is balanced with the wind force of the external wind.

[0024] In an implementation, the control method further comprises that the unmanned aerial vehicle adjusts the rotation speed of the rotor according to the weight of the unmanned aerial vehicle to keep the unmanned aerial vehicle hovering; adjusting the rotation speed of the rotor according to the weight of the unmanned aerial vehicle to keep the unmanned aerial vehicle hovering comprises:

[0025] obtaining the current weight of the unmanned aerial vehicle and the flow rate of the spray head;

[0026] reducing the rotation speed of the rotor according to the weight of the unmanned aerial vehicle and the flow rate of the spray head, so that the unmanned aerial vehicle hovers.

[0027] In an implementation, the unmanned aerial vehicle is controlled to fly parallel to the photovoltaic panel when the spray head is controlled to be turned on to clean the photovoltaic panel, which comprises:

[0028] obtaining a tilt angle of the photovoltaic panel and the horizontal plane;

[0029] obtaining a position of the unmanned aerial vehicle;

[0030] receiving a position of a flight destination of the unmanned aerial vehicle;

[0031] The flight path of the unmanned aerial vehicle is determined according to the inclination angles of the photovoltaic panel and the horizontal plane, the position of the unmanned aerial vehicle, and the position of the flight destination of the unmanned aerial vehicle, so that the flight path of the unmanned aerial vehicle is parallel to the photovoltaic panel.

[0032] In an implementable manner, the unmanned aerial vehicle flying parallel to the photovoltaic panel further includes:

[0033] The first boundary of the photovoltaic panel is acquired.

[0034] The angles of the rotating shafts of the rotors and the height direction are adjusted, and the rotating speeds of the rotors are adjusted according to the first boundary, so that the flight path of the unmanned aerial vehicle is parallel to the first boundary.

[0035] In an implementable manner, the unmanned aerial vehicle has multiple spraying modes.

[0036] The spray head is controlled to be turned on to clean the photovoltaic panel, including:

[0037] The dirt degree level is determined according to the image of the attached object, and the dirt degree level includes a first level, a second level, and a third level.

[0038] The spraying mode is selected according to the dirt degree, and the spraying mode includes a wind spraying mode, a water spraying mode, and a wind-water mixed spraying mode.

[0039] When the dirt degree level is the first level, the spraying mode is the wind spraying mode.

[0040] When the dirt degree level is the second level, the spraying mode is the water spraying mode.

[0041] When the dirt degree level is the third level, the spraying mode is the wind-water mixed spraying mode.

[0042] In a second aspect, the application further provides an unmanned aerial vehicle for cleaning a photovoltaic panel based on the control method of the first aspect.

[0043] The control method and the unmanned aerial vehicle for cleaning a photovoltaic panel using the method provided by the application can adjust the posture of the support and the spraying mode of the spray head according to the position information of the attached object on the photovoltaic panel and the dirt degree when the unmanned aerial vehicle is performing a low-altitude cleaning operation, so that the support is parallel to the photovoltaic panel, the spray head faces the light-receiving surface of the photovoltaic panel, and the unmanned aerial vehicle flies parallel to the photovoltaic panel to perform the cleaning operation. The photovoltaic panel can be accurately and efficiently cleaned in a safe flight height range, so that the photovoltaic panel is cleaned more cleanly and more comprehensively. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the application or the background art, the drawings needed to be used in the embodiments of the application or the background art will be described below.

[0045] Figure 1 The structure of the unmanned aerial vehicle related to the application is shown in the figure;

[0046] Figure 2 This is a flowchart of the control method involved in this application;

[0047] Figure 3 This is a schematic diagram of the first working path of the UAV involved in this application;

[0048] Figure 4 This is a schematic diagram of the second working path of the UAV involved in this application;

[0049] Figure 5 This is a schematic diagram of the passive control mode of the UAV involved in this application;

[0050] Figure 6 This is a schematic diagram of the automatic control mode of the unmanned aerial vehicle involved in this application.

[0051] Attached Figure Captions

[0052] 1-Fuselage, 2-Folding arm, 3-Bracket, 4-Nozzle, 5-Rotor, 6-Shaft.

[0053] 71-Current position, 72-Destination position, 73-First working path, 74-Photovoltaic panel, 75-Horizontal plane;

[0054] 76-Unmanned Aerial Vehicle, 77-First Boundary, 78-Second Working Path. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0056] Please see Figure 1 The drone includes a fuselage 1, a folding arm 2, and a support 3. The fuselage 1 is rotatably connected to one end of the folding arm 2, and the end of the folding arm 2 away from the fuselage 1 is rotatably connected to the support 3. The support 3 is equipped with a nozzle 4. The fuselage 1 is connected to a rotor 5 via a pivot 6, which is hinged to the fuselage 1. This application utilizes a drone for low-altitude cleaning operations. The drone adjusts the attitude of the support 3 and the spray pattern of the nozzle 4 based on the location and degree of dirt on the photovoltaic panel. This ensures that the support 3 is parallel to the photovoltaic panel, the nozzle 4 faces the dirt on the photovoltaic panel, and the drone flies parallel to the photovoltaic panel for cleaning. Within a safe flight altitude range, it accurately and efficiently cleans the dirt on the photovoltaic panel, resulting in a cleaner and more comprehensive cleaning. Please refer to [link to relevant documentation]. Figure 2 , Figure 3 and Figure 4 The control method steps are as follows:

[0057] S01, obtain the tilt angle between the photovoltaic panel 74 and the horizontal plane 75.

[0058] The drone 76 acquires images of the photovoltaic panel 74 and the horizontal surface 75, detects the boundaries of the photovoltaic panel 74 and the horizontal surface 75, extracts feature points, and forms a stereoscopic vision of the photovoltaic panel 74 and the horizontal surface 75 based on the extracted feature points, thereby determining the tilt angle of the photovoltaic panel 74 and the horizontal surface 75. Based on the acquired tilt angle of the photovoltaic panel 74 and the horizontal surface 75, the tilt angle of the drone 76's support 3 is adjusted to ensure that the gas or liquid sprayed from the nozzle 4 impacts the photovoltaic panel 74 at an optimal angle during cleaning operations, thus cleaning the photovoltaic panel 74 efficiently.

[0059] S02, Obtain the location information of the objects attached to the photovoltaic panel.

[0060] Before cleaning the photovoltaic panel 74, the drone 76 first determines the location, size, and degree of deposits on the panel. This information determines the drone 76's position relative to the panel and its spraying mode, ensuring precise and efficient cleaning of deposits such as dust and grime. If the photovoltaic panel 74 has only light dust or a small amount of grime that is easily blown away from the sun-receiving surface, the drone 76 uses a wind spray mode. If the panel has a large amount of grime that a wind spray mode alone cannot thoroughly clean, the drone 76 uses a water spray mode. The stronger water mist is more effective at removing large areas and deep deposits. Alternating between wind and water spray modes extends the drone 76's runtime and improves cleaning efficiency.

[0061] S02 includes the following sub-steps:

[0062] S201, the drone 76 receives the position signal of the photovoltaic panel 74 and flies to the top of the photovoltaic panel 74 according to the position signal.

[0063] The drone 76 receives the position signal from the photovoltaic panel 74, identifies its own position signal, compares its own position signal with the position signal of the photovoltaic panel 74, uses the position signal of the photovoltaic panel 74 as a reference point, and its own position signal as a starting point to plan a working path. It then flies to a position above the photovoltaic panel 74 according to this working path. For example, if the photovoltaic panel 74's own position is position A and its position is position B, the drone 76, after receiving the information, uses position B as a reference point and flies from position A to a position above B. The distance between the drone 76 and position B is determined by the distance between the drone 74 and position B. The image obtained from photovoltaic panel 74 indicates the presence of deposits. If the photovoltaic panel 74 has only floating dust or a small amount of dirt, which is lightweight and easily blown away from the sun-receiving surface, then drone 76 selects the wind spray mode. In this case, the optimal cleaning distance of drone 76 from position B is five to eight centimeters. If the photovoltaic panel 74 has a large amount of dirt, the wind spray mode alone is insufficient for thorough cleaning. In this case, drone 76 selects the water spray mode, which has a stronger water mist force, making it easier to remove large areas and deep deposits of dirt. In this case, the optimal cleaning distance of drone 76 from position B is one to three meters. If drone 76 does not receive a cleaning operation signal, it turns off the spray mode and remains in standby mode. If it receives a cleaning operation signal, it flies parallel to photovoltaic panel 74 to perform the cleaning operation.

[0064] S202, Drone 76 takes pictures of photovoltaic panel 74 to obtain images.

[0065] The cleaning operation signal of the drone 76 depends on the image analysis of the photovoltaic panel 74 by the drone 76 of the deposits present on the photovoltaic panel 74. The drone 76 takes pictures of the photovoltaic panel 74 to obtain images, for example, by acquiring images of the photovoltaic panel 74 from different angles through at least two camera sensors, and then identifies the degree of dirt on the photovoltaic panel 74 based on the grayscale of the images.

[0066] S203, Analyze the image to determine the location information of the attachments in the photovoltaic panel 74.

[0067] After acquiring an image of deposits on the photovoltaic panel 74, the drone 76 first preprocesses the image, such as denoising and enhancing contrast. Then, it extracts pixels from the image and analyzes their grayscale values. Grayscale regions indicate the location and size of the deposits, and the degree of grayscale intensity indicates the extent of deposit deposition. By analyzing the image, the drone 76 determines the location information of the deposits on the photovoltaic panel 74, thereby identifying the areas of the photovoltaic panel 74 that require cleaning.

[0068] S03, adjust the flight position of UAV 76 based on location information.

[0069] The drone 76 determines its position relative to the photovoltaic panel 74 based on the location of the attached objects. It determines its flight altitude based on the area and degree of deposition of the attached objects. If the area of ​​attached objects is large, the drone 76 needs to rise to a suitable altitude to ensure that the attached objects are within the cleaning range of the drone 76 and to avoid missed cleaning. If the deposition of the attached objects is deep, the drone 76 needs to descend to a suitable altitude. Within a safe flight altitude range, the closer the nozzle 4 on the support 3 of the drone 76 is to the photovoltaic panel 74, the higher the cleaning efficiency of the drone 76.

[0070] S03 includes the following sub-steps:

[0071] S301, determine the height of the attachment based on location information.

[0072] The drone 76 analyzes the height of the attachments on the photovoltaic panel 74 from the ground based on the image of the attachments on the photovoltaic panel 74.

[0073] S302 determines the drone's flight position based on the height of the attachment, the tilt angle of the photovoltaic panel and the horizontal plane, and the preset spray distance of the nozzle.

[0074] The drone's flight position projection on the photovoltaic panel coincides with any deposits on the panel. The drone's flight position has a preset flight height relative to the photovoltaic panel. This preset flight height is determined based on the preset spray distance of the drone's nozzles when cleaning the photovoltaic panel, the ground clearance of the deposits, and the tilt angle of the photovoltaic panel relative to the horizontal plane. For example, for the drone 76 using water spray mode, the preset flight height of the drone 76 relative to the photovoltaic panel 74 varies from one meter to three meters depending on the degree of deposits; for the drone 76 using wind spray mode, the preset flight height of the drone 76 relative to the photovoltaic panel 74 varies from five centimeters to ten centimeters depending on the degree of deposits. If the drone's flight position projection on the photovoltaic panel coincides with any deposits on the panel, the drone 76 measures its acceleration at the X, Y, and Z altitudes and its angular velocity around the panel in three revolutions. Integrating the acceleration yields the drone 76's velocity, integrating the velocity yields the drone 76's displacement, and integrating the angular velocity yields the drone 76's rotation angle, thus obtaining the drone 76's motion attitude. By combining the displacement and attitude of UAV 76, the current flight altitude and orientation of UAV 76 are determined. The current flight altitude is compared with the preset flight altitude, and the difference between the current flight altitude and the preset flight altitude generates a control output. After accumulating the change of altitude error over time to eliminate static error, the rotation speed of rotor 5 is adjusted according to the altitude change rate.

[0075] If the current flight altitude is higher than the preset flight altitude, it means that the drone 76 is currently positioned above the preset flight altitude for cleaning the photovoltaic panel 74. For example, when using water spray mode, the drone 76 is more than three meters away from the photovoltaic panel 74, and when using wind spray mode, it is more than eight centimeters away. To ensure the cleaning effect of the drone 76, the rotation speed of the rotor 5 of the drone 76 is reduced, decreasing the lift of the drone 76, allowing the drone 76 to gradually descend to the preset flight altitude. If the current flight altitude is lower than the preset flight altitude, for example, when using water spray mode, the drone 76 is less than one meter away from the photovoltaic panel 74, and when using wind spray mode, it is less than five centimeters away. To avoid the drone 76 colliding with the photovoltaic panel 74 during cleaning, the rotation speed of the rotor 5 of the drone 76 is increased, increasing the lift of the drone 76, allowing the drone 76 to gradually ascend to the preset flight altitude.

[0076] S04, according to the tilt angle, the folding arm 2 of the drone 76 is unfolded so that the bracket 3 is parallel to the photovoltaic panel 74 and the nozzle 4 faces the attachment in the photovoltaic panel 74.

[0077] After the drone 76 obtains the tilt angle between the photovoltaic panel 74 and the horizontal plane 75, it releases the brake on the folding arm 2 and adjusts the rotation of the folding arm 2 to make it perpendicular to the horizontal plane 75. Then, it closes the brake on the folding arm 2 and releases the brake on the bracket 3. The drone 76 controls the bracket 3 to rotate so that the angle between the bracket 3 and the folding arm 2 is complementary to the tilt angle between the photovoltaic panel 74 and the horizontal plane 75, ensuring that the bracket 3 is parallel to the photovoltaic panel 74. It is worth noting that the bracket 3 of the drone 76 is parallel to the photovoltaic panel 74, meaning that the nozzles 4 on the bracket 3 are directly facing the deposits on the photovoltaic panel 74. After the bracket 3 is parallel to the photovoltaic panel 74, the brake on the bracket 3 is closed. The drone 76 controls the nozzles 4 on the bracket 3 to face the deposits on the photovoltaic panel 74. Considering the nozzle flow rate and the drone 76's endurance, if the drone 76 uses a 50L water tank, and the water consumption of a single nozzle 4 is controlled to be less than or equal to 0.8 liters per second, to ensure the drone 76 has sufficient cleaning time, a maximum of four nozzles 4 can be used on the bracket 3.

[0078] S04 includes the following sub-steps:

[0079] S401, obtain the current angle between bracket 3 and the horizontal plane 75;

[0080] Before the folding arm 2 is unfolded, the drone 76 measures the current angle between the support 3 and the horizontal plane 75. If the current angle is 0 degrees or 180 degrees, it means that the support 3 is in the original position and the folding arm 2 can be unfolded directly. If the current angle is not 0 degrees or 180 degrees, the support 3 needs to be rotated to the original position before the folding arm 2 is unfolded.

[0081] S402, control the unfolding of the folding arm 2 according to the current angle between the bracket 3 and the horizontal plane 75 and the tilt angle;

[0082] The drone 76 controls the folding arm 2 to unfold. When the folding arm 2 unfolds to the vertical horizontal plane 75, the drone 76 measures the tilt angle between the bracket 3 and the folding arm 2. If the angle between the bracket 3 and the folding arm 2 and the tilt angle between the photovoltaic panel 74 and the horizontal plane 75 are complementary angles, then the bracket 3 and the photovoltaic panel 74 are parallel.

[0083] S403, control the bracket 3 to rotate relative to the folding arm 2 until the angle between the bracket 3 and the folding arm 2 is complementary to the tilt angle.

[0084] When the folding arm 2 is perpendicular to the horizontal plane 75, the drone 76 releases the brake of the bracket 3 and controls the bracket 3 to rotate so that the angle between the bracket 3 and the folding arm 2 is complementary to the tilt angle between the photovoltaic panel 74 and the horizontal plane 75, so that the bracket 3 is parallel to the photovoltaic panel 74.

[0085] S05, control the nozzle 4 to open to clean the deposits in the photovoltaic panel 74.

[0086] The drone 76 has multiple spraying modes. After the drone 76 controls the nozzle 4 to face the photovoltaic panel 74, it analyzes the degree of dirtiness of the photovoltaic panel 74 based on the acquired image of the photovoltaic panel 74. The degree of dirtiness includes Level 1, Level 2, and Level 3. The spraying mode is selected according to the degree of dirtiness, including wind spraying, water spraying, and a combined wind and water spraying mode. When the degree of dirtiness is Level 1, the spraying mode is wind spraying. When the degree of dirtiness is Level 2, the spraying mode is water spraying. When the degree of dirtiness is Level 3, the spraying mode is a combined wind and water spraying mode.

[0087] During cleaning operations, the drone 76 has two movement states: hovering and flying parallel to the photovoltaic panel 74. Under normal operating conditions, the drone 76 controls the rotation speed of its rotor 5 to ensure that the force generated by the rotor 5 is equal to the weight of the drone 76, thus hovering above the photovoltaic panel 74. For example, based on the height of the drone 76 above the photovoltaic panel 74 and the diameter of the drone 76's structure, the drone 76 controls its vertical movement in the direction perpendicular to the photovoltaic panel 74 to not exceed 10% of its height above the photovoltaic panel 74, and its horizontal and backward movement in the direction parallel to the photovoltaic panel 74 to not exceed 10% of the diameter of the drone 76's structure; this constitutes hovering. In case of strong winds, the drone 76 can also maintain hovering according to the external wind conditions. The control steps are as follows:

[0088] S601, obtains the wind direction and force of the outside wind.

[0089] The UAV 76 monitors the wind direction and force of its surroundings in real time, and can also predict wind direction and force based on existing data to adjust subsequent flight. According to the estimated wind conditions, the UAV 76 adjusts the rotation speed of its rotor 5 accordingly to counteract the influence of the external wind and maintain the predetermined speed and altitude.

[0090] S602, based on the direction and force of the outside wind, the UAV 76 adjusts the rotation of the pivot 6 relative to the fuselage 1 and adjusts the rotation speed of the rotor 5 so that the wind force generated by the rotor 5 is balanced with the outside wind force.

[0091] After obtaining the wind direction, the drone 76 controls the rotation shaft 6 of the rotor 5 to rotate, making the shaft 6 parallel to the wind direction. Simultaneously, it controls the rotation speed of the rotor 5 according to the wind force, generating a wind force equal to the outside wind, thus maintaining the drone 76 at a preset flight altitude. Furthermore, in strong wind conditions, the drone 76 can choose to increase or decrease its flight altitude to avoid areas with strong winds. It is worth noting that if the wind conditions exceed the drone 76's handling capacity, the drone 76 will automatically return to its takeoff point, and if necessary, it will seek a safe location for an emergency landing.

[0092] In addition to strong wind conditions, the UAV 76 also dynamically adjusts the rotation speed of its rotor 5 to maintain hovering during cleaning operations. As water consumption increases during cleaning operations, the water level in the UAV 76's water tank decreases, resulting in a corresponding decrease in the UAV 76's weight. If the rotor 5 of the UAV 76 continues to operate at its full-load speed under these conditions, it would be difficult to guarantee the correctness of its working position. This application takes this into consideration and has made improvements to the control method. The control steps are as follows:

[0093] S701, obtain the current drone weight (76) and nozzle flow rate.

[0094] The current weight of drone 76 consists of its own weight and the weight of the water contained in its internal water tank. In water spray mode, the weight change of drone 76 is due to the decrease in the amount of water in the tank. Drone 76 determines the water tank's water consumption by measuring the spray diameter and spray time per unit time to obtain the nozzle flow rate. Based on the nozzle flow rate, drone 76 calculates the water consumption of nozzle 4 to determine the water tank's water consumption, thus determining the current weight of drone 76. As the weight of drone 76 changes during cleaning operations, the rotation speed of drone 76's rotor 5 should also be adjusted accordingly to ensure drone 76 can hover.

[0095] S702 reduces the rotational speed of rotor 5 based on the weight of drone 76 and nozzle flow rate to keep drone 76 hovering.

[0096] When the weight of the drone 76 decreases, the water consumption of the drone 76 at the next moment is predicted based on the flow rate of the nozzle 4, and the weight of the drone 76 at the next moment is calculated. Based on the weight of the drone 76 at the next moment, the rotation speed of the rotor 5 of the drone 76 is adjusted to reduce the rotation speed of the rotor 5 to ensure that the drone 76 does not exceed the predetermined flight altitude as the water consumption increases, and remains hovering.

[0097] For example, the lift calculation formula for the UAV 76 is as follows:

[0098] L=1 / 2×ρ×V 2 ×S×C L

[0099] Where: L - lift (Newtons), ρ - air density (kg / m³), V - the flight speed of the UAV relative to the air (m / s), S - the area swept by the rotor (m²), C L - Lift coefficient (dimensionless coefficient, depending on the shape and attitude of rotor 5).

[0100] The formula for calculating the weight of the UAV 76 is as follows:

[0101] W = EW + PL

[0102] Where: W - weight of UAV 76, EW - empty weight of UAV 76 (weight of UAV 76's own structure and equipment), PL - payload of UAV 76 (mainly the weight of water carried in the water tank).

[0103] In this application, the effective payload of the UAV 76 = original water volume - nozzle flow rate × usage time.

[0104] To maintain stable flight, the lift of the drone 76 must equal its weight, i.e., L = W. During cleaning operations, the drone 76 continuously calculates and adjusts the rotational speed of the rotor 5 according to the above principles and formulas to ensure that the drone 76 does not exceed the predetermined flight altitude as water consumption increases, thus maintaining hovering.

[0105] The drone 76 flying parallel to the photovoltaic panel 74 has two working paths; please refer to [link / reference]. Figure 3 This is the first working path 73 for the UAV 76. After receiving the destination position 72, the UAV 76 moves from its current position 71 parallel to the photovoltaic panel 74 to the destination position 72. The control method for the first working path 73 is as follows:

[0106] S801, obtain the tilt angle between the photovoltaic panel 74 and the horizontal plane 75.

[0107] The drone 76 acquires images of the photovoltaic panel 74 and the horizontal surface 75, detects the boundaries of the photovoltaic panel 74 and the horizontal surface 75, extracts feature points, and forms a stereoscopic vision of the photovoltaic panel 74 and the horizontal surface 75 based on the extracted feature points, thereby determining the tilt angle of the photovoltaic panel 74 and the horizontal surface 75. Based on the acquired tilt angle of the photovoltaic panel 74 and the horizontal surface 75, the tilt angle of the drone 76 support 3 is adjusted to ensure that the gas or liquid sprayed from the nozzle 4 impacts the photovoltaic panel 74 at an optimal angle during the cleaning operation, thus cleaning the photovoltaic panel 74 efficiently.

[0108] S802, obtain the location of drone 76.

[0109] The UAV 76 measures its own acceleration at three altitudes (X, Y, and Z) and its angular velocity around three revolutions. Integrating the acceleration yields the velocity, and integrating the velocity yields the displacement. Integrating the angular velocity yields the rotation angle, which in turn determines the UAV 76's attitude, such as its pitch angle. Simultaneously, the UAV 76 measures the strength and direction of the Earth's magnetic field, providing an absolute reference direction. Combining the UAV 76's displacement, attitude, and reference direction, its position and orientation are determined, enabling navigation and motion control.

[0110] S803 receives the location of the destination of the UAV 76 flight.

[0111] The flight target position 72 of the first working path of the UAV 76 is a set value, and the UAV 76 communicates and receives the data through a mobile network.

[0112] S804, based on the tilt angle of the photovoltaic panel 74 and the horizontal plane 75, the position of the drone 76, and the target flight position of the drone 76, determine the flight path of the drone 76 so that the flight path of the drone 76 is parallel to the photovoltaic panel 74.

[0113] After determining the position of the drone 76 and the flight destination position 72, the drone 76 adjusts its motion attitude, motion direction and rotor speed 5 according to the current position 71, the destination position 72 and the tilt angle of the photovoltaic panel 74 and the horizontal plane 75, so that the drone 76 moves from the current position 71 to the destination position 72 parallel to the photovoltaic panel 74, so as to ensure the cleaning effect of the drone 76.

[0114] Please see Figure 4 This is the second working path 78 for the drone 76. After the drone 76 identifies the first boundary 77 of the photovoltaic panel 74, it cleans the photovoltaic panel 74 from top to bottom, parallel to the first boundary 77. This top-to-bottom cleaning method avoids watermarks after cleaning. The control method for the second working path 78 is as follows:

[0115] S901, obtain the first boundary 77 of the photovoltaic panel 74.

[0116] The drone 76 extracts the first boundary 77 information of the photovoltaic panel 74 based on the obtained image of the photovoltaic panel 74, and provides a directional reference for the working path of the photovoltaic panel 74.

[0117] S902, adjust the rotation axis 6 of rotor 5 and the angle in the altitude direction according to the first boundary 77, and adjust the rotation speed of rotor 5 so that the flight path of UAV 76 is parallel to the first boundary 77.

[0118] The drone 76 starts at one end of the first boundary 77 and ends at the other end of the first boundary 77. Without changing the cleaning distance from the photovoltaic panel 74, it adjusts the angle of the rotor shaft 6 and the altitude direction, as well as the rotation speed of the rotor 5, to fly from one end of the first boundary 77 to the other end of the first boundary 77, ensuring that the drone 76's flight path is parallel to the first boundary 77, i.e., the drone 76 cleans parallel to the photovoltaic panel 74. After the drone 76 reaches the end point from the starting point of the first boundary 77, it moves to a new starting point one drone length away from the starting point of the first boundary 77 and starts cleaning again. This process is repeated until cleaning is complete, ensuring that the drone 76 cleans more thoroughly.

[0119] The drone 76 can reach the photovoltaic panel 74 from the takeoff point using both passive and automatic control modes. Please refer to [link / reference]. Figure 5 This is the passive control mode for drone 76. In this mode, the operator controls drone 76 to fly above photovoltaic panel 74 via a central control console or remote controller, enabling drone 76 to perform cleaning operations. Please see... Figure 6 This is the automatic control mode of the drone 76. After the drone 76 is turned on, it receives wireless network and satellite signals, receives the location information of the photovoltaic panel 74, and automatically plans a flight path to fly above the photovoltaic panel 74 to carry out cleaning operations.

[0120] The present invention also provides a drone 76 for cleaning photovoltaic panels 74 based on the above control method.

[0121] The drone 76 includes a fuselage 1, a folding arm 2, and a support 3. The fuselage 1 is rotatably connected to one end of the folding arm 2, and the end of the folding arm 2 away from the fuselage 1 is rotatably connected to the support 3. The support 3 is equipped with a nozzle 4.

[0122] Before cleaning the photovoltaic panel 74, the drone 76 first determines the location, size, and degree of deposits on the photovoltaic panel 74. This information is used to determine the drone 76's position relative to the photovoltaic panel 74 and its spraying mode, ensuring that the drone 76 can accurately and efficiently clean the deposits, such as dust and dirt, on the photovoltaic panel 74. If there is only dust or a small amount of dirt on the photovoltaic panel 74, which is lightweight and easily blown away from the sun-receiving surface, the drone 76 selects the wind spray mode. If there is a large amount of dirt on the photovoltaic panel 74, the wind spray mode alone is insufficient for thorough cleaning, so the drone 76 selects the water spray mode. The water mist has a stronger impact, making it easier to remove large areas and deep deposits of dirt.

[0123] The drone 76 determines its position relative to the photovoltaic panel 74 based on the location of the attached material. It then determines its preset flight altitude based on the area of ​​the attached material, the degree of deposition, the height of the material above the ground, the tilt angle between the photovoltaic panel and the horizontal plane, and the preset spray distance of the nozzle. For example, if the area of ​​attached material is large, the drone 76 needs to ascend to a suitable altitude to ensure the material is within its cleaning range and to avoid missed areas. If the material is deeply deposited, the drone 76 needs to descend to a suitable altitude. Within a safe flight altitude range, the closer the nozzle 4 on the drone 76's support 3 is to the photovoltaic panel 74, the higher the cleaning efficiency of the drone 76.

[0124] After acquiring images of the photovoltaic panel 74 and the horizontal surface 75, the drone 76 detects the boundaries of the photovoltaic panel 74 and the horizontal surface 75, extracts feature points, and forms a stereoscopic vision of the photovoltaic panel 74 and the horizontal surface 75 based on the extracted feature points, thereby determining the tilt angle of the photovoltaic panel 74 and the horizontal surface 75. Based on the acquired tilt angle of the photovoltaic panel 74 and the horizontal surface 75, the tilt angle of the drone 76's support 3 is adjusted to ensure that the gas or liquid sprayed from the nozzle 4 impacts the photovoltaic panel 74 at an optimal angle during the cleaning operation, thus cleaning the photovoltaic panel 74 efficiently.

[0125] After the drone 76 obtains the tilt angle between the photovoltaic panel 74 and the horizontal plane 75, it engages the brake on the folding arm 2 of the drone 76 and adjusts the rotation of the folding arm 2 to make it perpendicular to the horizontal plane 75. Then, it engages the brake on the folding arm 2 and engages the brake on the bracket 3. The drone 76 controls the bracket 3 to rotate so that the angle between the bracket 3 and the folding arm 2 is complementary to the tilt angle between the photovoltaic panel 74 and the horizontal plane 75, ensuring that the bracket 3 is parallel to the photovoltaic panel 74. It is worth noting that the bracket 3 of the drone 76 is parallel to the photovoltaic panel 74, meaning that the nozzles 4 on the bracket 3 are directly facing the deposits on the photovoltaic panel 74. After the bracket 3 is parallel to the photovoltaic panel 74, the brake on the bracket 3 is engaged. The drone 76 controls the nozzles 4 on the bracket 3 to face the deposits on the photovoltaic panel 74. Considering the flow rate of the nozzles 4 and the endurance of the drone 76, if the drone 76 uses a 50L water tank, and the water consumption of a single nozzle 4 is controlled to be less than or equal to 0.8 liters per second, to ensure that the drone 76 has sufficient cleaning time, a maximum of four nozzles 4 can be used on the bracket 3.

[0126] The drone 76 also features multiple spraying modes. After the drone 76 controls its nozzle to face the photovoltaic panel 74, it analyzes the degree of dirtiness of the deposits on the photovoltaic panel 74 based on the acquired images. The dirtiness levels are categorized into Level 1, Level 2, and Level 3. The drone selects the appropriate spraying mode based on the dirtiness level, including wind spray, water spray, and a combined wind and water spray. When the dirtiness level is Level 1, the spraying mode is wind spray. When the dirtiness level is Level 2, the spraying mode is water spray. When the dirtiness level is Level 3, the spraying mode is a combined wind and water spray. After acquiring the location and image information of the deposits on the photovoltaic panel 74, the drone 76 hovers at a suitable cleaning height above the photovoltaic panel 74, with its support parallel to the photovoltaic panel and its nozzle facing the deposits. It employs the corresponding spraying mode for different deposit images, ensuring that the drone cleans the deposits on the photovoltaic panel at the appropriate height and angle, resulting in a cleaner and more comprehensive cleaning.

[0127] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0128] Furthermore, the use of terms such as "first," "second," etc., in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0129] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0130] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0131] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control method for cleaning photovoltaic panels using unmanned aerial vehicles (UAVs), characterized in that, The drone includes a fuselage, a folding arm, and a support frame. The fuselage is rotatably connected to one end of the folding arm, and the end of the folding arm away from the fuselage is rotatably connected to the support frame. The support frame is equipped with a nozzle. The control method includes: Obtain the tilt angle between the photovoltaic panel and the horizontal plane; Obtain the location information of the attachments on the photovoltaic panels; The drone's flight position is adjusted based on the location information; The folding arm of the drone is unfolded according to the tilt angle so that the bracket is parallel to the photovoltaic panel and the nozzle faces the attachment in the photovoltaic panel; Control the nozzle to open in order to clean the deposits in the photovoltaic panel; The drone also includes a rotor, the rotor's axis of rotation being hinged to the fuselage; adjusting the drone's flight position based on the position information includes: The height of the attachment is determined based on the location information; The flight position of the drone is determined based on the height of the attached object, the tilt angle between the photovoltaic panel and the horizontal plane, and the preset spray distance of the nozzle. The step of controlling the unfolding of the drone's folding arm according to the tilt angle to make the support parallel to the photovoltaic panel includes: Obtain the current angle between the bracket and the horizontal plane; The folding arm is deployed based on the current angle between the bracket and the horizontal plane and the tilt angle. Control the bracket to rotate relative to the folding arm until the angle between the bracket and the horizontal plane is equal to the tilt angle; When controlling the nozzle to open to clean the photovoltaic panel, the drone is controlled to fly parallel to the photovoltaic panel; The control of the drone to fly parallel to the photovoltaic panel includes: Obtain the tilt angle between the photovoltaic panel and the horizontal plane; Obtain the location of the drone; Receive the location of the drone's flight destination; The flight path of the drone is determined based on the tilt angle between the photovoltaic panel and the horizontal plane, the position of the drone, and the position of the drone's flight destination, so that the flight path of the drone is parallel to the photovoltaic panel.

2. The control method according to claim 1, characterized in that, The acquisition of the location information of the attachments on the photovoltaic panel includes: Receives the position signal of the photovoltaic panel and flies to above the photovoltaic panel according to the position signal; Take a picture of the photovoltaic panel to obtain an image; The image is analyzed to determine the location information of the attachments in the photovoltaic panel.

3. The control method according to claim 1, characterized in that, When controlling the nozzle to open to clean the photovoltaic panel, the drone is kept hovering; keeping the drone hovering includes: Obtain the direction and force of the outside wind; The rotation of the shaft relative to the fuselage is adjusted according to the direction and force of the outside wind, and the rotation speed of the rotor is also adjusted so that the wind force generated by the rotor is balanced with the outside wind force.

4. The control method according to claim 1, characterized in that, The control method further includes the drone adjusting the rotor speed according to the drone's weight to keep the drone hovering; the step of adjusting the rotor speed according to the drone's weight to keep the drone hovering includes: Obtain the current drone weight and nozzle flow rate; The rotor speed is reduced according to the drone's weight and nozzle flow rate to keep the drone hovering.

5. The control method according to claim 4, characterized in that, The control of the drone to fly parallel to the photovoltaic panel also includes: Obtain the first boundary of the photovoltaic panel; Adjust the angle of the rotor shaft and the altitude direction, as well as the rotor speed, according to the first boundary, so that the flight path of the UAV is parallel to the first boundary.

6. The control method according to claim 1, characterized in that, The drone has multiple jetting modes; The control of the nozzle to open for cleaning the photovoltaic panel includes: The level of dirtiness is determined based on the image of the attachments. The level of dirtiness includes Level 1, Level 2 and Level 3. Select the spray mode according to the degree of dirtiness. Spray modes include air spray mode, water spray mode, and air-water mixed spray mode. When the level of dirt is Level 1, the spray mode is the air spray mode; When the level of dirt is level two, the spraying mode is water spray mode; When the level of dirt is level three, the spraying mode is a wind and water mixed spray mode.

7. A drone, characterized in that, The drone cleans the photovoltaic panels using the control method described in any one of claims 1-6.

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