Unmanned aerial vehicle and control method for cleaning photovoltaic panel based on unmanned aerial vehicle

Abstract

The invention discloses an unmanned aerial vehicle and a control method for cleaning a photovoltaic panel based on the unmanned aerial vehicle, the unmanned aerial vehicle comprises a fuselage, a folding arm and a support, the fuselage is rotatably connected with one end of the folding arm, the end, away from the fuselage, of the folding arm is rotatably connected with the support, and the support is provided with a sprayer. Adjusting the flight height of the unmanned aerial vehicle according to the position information; obtaining an inclination angle between the photovoltaic panel and the horizontal plane; a folding arm of the unmanned aerial vehicle is controlled to be unfolded according to the inclination angle, so that the support is parallel to the photovoltaic panel, and the nozzle faces the light receiving face of the photovoltaic panel; and controlling the nozzle to open to clean the photovoltaic panel. According to the photovoltaic panel cleaning device, the nozzles face attachments in the photovoltaic panel, so that the efficiency of cleaning the photovoltaic panel is improved, and meanwhile, the photovoltaic panel can be cleaned more cleanly.

Description

Technical Field

[0001] The present application belongs to the technical field of photovoltaic power stations, and in particular relates to a drone and a control method for cleaning photovoltaic panels based on the drone. Background Art

[0002] With the popularization of photovoltaic power generation, the cleaning problem of photovoltaic panels has become increasingly prominent, because pollutants such as dust, bird droppings, and leaves will reduce the power generation efficiency of photovoltaic panels. Drone cleaning of photovoltaic panels is an emerging technical solution, mainly used for the maintenance and cleaning of large photovoltaic power stations. At present, the range of drone cleaning of photovoltaic panels is limited during operation, and the cleaning is not thorough enough, resulting in uneven removal of floating dust and dirt on photovoltaic panels. Summary of the invention

[0003] The present application provides a drone and a control method for cleaning photovoltaic panels based on the drone, which solves the problem that the drone does not clean thoroughly enough during the cleaning operation, resulting in uneven removal of floating dust and dirt on the photovoltaic panels.

[0004] In a first aspect, the present application provides a control method for cleaning photovoltaic panels based on a drone, wherein the drone comprises a fuselage, a folding arm and a bracket, wherein the fuselage is rotatably connected to one end of the folding arm, and an end of the folding arm away from the fuselage is rotatably connected to the bracket, and the bracket is provided with a nozzle, and the control method comprises:

[0005] Get the tilt angle between the photovoltaic panel and the horizontal plane;

[0006] Obtaining location information of objects attached to photovoltaic panels;

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

[0008] Controlling the folding arm of the drone to unfold 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;

[0009] The nozzle is controlled to open to clean the attached objects in the photovoltaic panel.

[0010] In a feasible implementation, obtaining the location information of the attachments on the photovoltaic panel includes:

[0011] Receive the position signal of the photovoltaic panel and fly above the photovoltaic panel according to the position signal;

[0012] Photographing the photovoltaic panel to obtain an image;

[0013] The images are analyzed to determine the location information of the attached objects in the photovoltaic panel.

[0014] In a feasible implementation, the drone further includes a rotor, and a rotating shaft of the rotor is hinged to the fuselage; adjusting the flight position of the drone according to the position information includes:

[0015] Determine the height of the attachment based on the position information;

[0016] The flight position of the drone is determined based on the height of the attachment, the inclination angle of the photovoltaic panel and the horizontal plane, and the preset spray distance of the nozzle.

[0017] In a feasible implementation, controlling the folding arm of the drone to unfold according to the tilt angle so that the bracket is parallel to the photovoltaic panel includes:

[0018] Get the current angle between the bracket and the horizontal plane;

[0019] Control the unfolding of the folding arm according to the current angle and inclination angle between the bracket and the horizontal plane;

[0020] The support is controlled 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 to each other.

[0021] In a feasible implementation, when the nozzle is controlled to be turned on to clean the photovoltaic panel, the drone is kept hovering; the drone is kept hovering including:

[0022] Get the wind direction and wind force of the outside wind;

[0023] The rotation of the shaft relative to the fuselage is adjusted according to the wind direction and wind force of the external wind, and the rotation speed of the rotor is adjusted to balance the wind force generated by the rotor with the wind force of the external wind.

[0024] In a feasible implementation, the control method further includes the UAV adjusting the rotor speed according to the weight of the UAV so that the UAV can keep hovering; adjusting the rotor speed according to the weight of the UAV so that the UAV can keep hovering includes:

[0025] Get the current drone weight and nozzle flow rate;

[0026] Reduce the rotor speed according to the weight of the drone and the nozzle flow rate to keep the drone hovering.

[0027] In a feasible implementation, when the nozzle is controlled to be turned on 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:

[0028] Get the tilt angle between the photovoltaic panel and the horizontal plane;

[0029] Get the location of the drone;

[0030] Receive the location of the drone’s flight destination;

[0031] The flight path of the drone is determined according to the inclination 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.

[0032] In a feasible implementation, the drone flying parallel to the photovoltaic panel also includes:

[0033] Get the first boundary of the photovoltaic panel;

[0034] The angle of the rotor shaft and the height direction is adjusted according to the first boundary, and the rotor speed is adjusted so that the flight path of the UAV is parallel to the first boundary.

[0035] In one possible implementation, the drone has multiple jet modes;

[0036] Control the nozzles to clean the photovoltaic panels, including:

[0037] Determine the dirtiness level according to the image of the attachment, and the dirtiness level includes the first level, the second level and the third level;

[0038] Select the spray mode according to the degree of dirtiness. The spray modes include wind spray mode, water spray mode, and wind and water mixed spray mode;

[0039] When the dirtiness level is level 1, the spray mode is the wind spray mode;

[0040] When the dirtiness level is the second level, the spray mode is the water spray mode;

[0041] When the dirtiness level is the third level, the spray mode is a wind and water mixed spray mode.

[0042] In a second aspect, the present invention further provides a drone for cleaning photovoltaic panels based on the control method of the first aspect.

[0043] The control method provided in the present application and the drone that uses this method to clean photovoltaic panels enable the drone to adjust the posture of the bracket and the spray pattern of the nozzle according to the location information of the attachments on the photovoltaic panels and the degree of dirtiness during low-altitude cleaning operations, so that the bracket is parallel to the photovoltaic panel, the nozzle faces the light-receiving surface of the photovoltaic panel, and the drone flies parallel to the photovoltaic panel to perform cleaning operations, thereby accurately and efficiently cleaning the photovoltaic panels within a safe flight altitude range, allowing the drone to clean more thoroughly and cover a more comprehensive range. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0045] Figure 1 This is a simplified diagram of the structure of the drone involved in this application;

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

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

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

[0051] Figure Annotation

[0052] 1-fuselage, 2-folding arm, 3-bracket, 4-nozzle, 5-rotor, 6-rotating shaft.

[0053] 71-current position, 72-destination position, 73-first working path, 74-photovoltaic panel, 75 horizontal plane;

[0054] 76-UAV, 77-First boundary, 78-Second working path. DETAILED DESCRIPTION

[0055] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0056] See also Figure 1 The UAV includes a fuselage 1, a folding arm 2 and a bracket 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 bracket 3. The bracket 3 is provided with a nozzle 4. The fuselage 1 is connected to the rotor 5 via a rotating shaft 6, and the rotating shaft 6 is hinged to the fuselage 1. This application uses a UAV for low-altitude cleaning operations. The UAV adjusts the posture of the bracket 3 and the spray mode of the nozzle 4 according to the location information and degree of dirtiness of the attachments on the photovoltaic panel, so that the bracket 3 is parallel to the photovoltaic panel, the nozzle 4 faces the attachments in the photovoltaic panel, and the UAV flies parallel to the photovoltaic panel for cleaning operations. The attachments in the photovoltaic panel are cleaned accurately and efficiently within a safe flight altitude range, so that the UAV cleans more thoroughly and covers a more comprehensive range. Please refer to Figure 2 , Figure 3 and Figure 4 , the control method steps are as follows:

[0057] S01 , obtaining the inclination 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 plane 75, detects the boundaries of the photovoltaic panel 74 and the boundaries of the horizontal plane 75, extracts feature points, and forms a stereoscopic vision of the photovoltaic panel 74 and the horizontal plane 75 based on the extracted feature points, thereby determining the inclination angle of the photovoltaic panel 74 and the horizontal plane 75. According to the acquired inclination angle of the photovoltaic panel 74 and the horizontal plane 75, the inclination angle of the bracket 3 of the drone 76 is adjusted to ensure that the gas or liquid ejected from the nozzle 4 during the cleaning operation of the drone 76 impacts the photovoltaic panel 74 at a better angle, thereby efficiently cleaning the photovoltaic panel 74.

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

[0060] Before the drone 76 cleans the photovoltaic panel 74, it first determines the location, area and degree of deposition of the attachments on the photovoltaic panel 74, so as to determine the relative position of the drone 76 to the photovoltaic panel 74 and the spray mode of the drone 76, so as to ensure that the drone 76 can accurately and efficiently clean the attachments on the photovoltaic panel 74, such as floating dust and dirt. If there is only floating dust or a small amount of dirt on the photovoltaic panel 74, which is light in weight and easily blown away from the light-receiving surface of the photovoltaic panel 74, the drone 76 selects the wind spray mode; if there is a lot of dirt on the photovoltaic panel 74, and it is difficult to clean it thoroughly with the wind spray mode alone, the drone 76 selects the water spray mode, which has a larger water mist impact force and is convenient for removing large-area and deeply deposited dirt. The alternation of the wind spray mode and the water spray mode of the drone 76 not only extends the endurance of the drone 76, but also improves the 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 above the photovoltaic panel 74 according to the position signal.

[0063] The drone 76 receives the position signal of the photovoltaic panel 74, identifies its own position signal, compares its own position signal with the position signal of the photovoltaic panel 74, takes the position signal of the photovoltaic panel 74 as a reference point and its own position signal as a starting point, plans a working path, and flies to the top of the photovoltaic panel 74 according to the working path. For example, the position of the photovoltaic panel 74 itself is position A, and the position of the photovoltaic panel 74 is position B. After receiving the information, the drone 76 takes position B as a reference point and flies from position A to the top of position B. At this time, the distance between the drone 76 and position B is calculated according to the distance between the drone 76 and position B. 6. If there is only floating dust or a small amount of dirt on the photovoltaic panel 74, which is light and easy to be blown away from the light-receiving surface of the photovoltaic panel 74, the drone 76 selects the wind spray mode. At this time, the best cleaning distance of the drone 76 from position B is five to eight centimeters; if there is a lot of dirt on the photovoltaic panel 74, it is difficult to clean it thoroughly with the wind spray mode alone, then the drone 76 selects the water spray mode, which has a larger water mist impact force and is convenient for removing large-area and deep-deposited dirt. At this time, the best cleaning distance of the drone 76 from position B is one to three meters. If the drone 76 does not receive a cleaning operation signal, the spray mode is turned off and it remains on standby; if it receives a cleaning operation signal, it flies parallel to the photovoltaic panel 74 to perform the cleaning operation.

[0064] S202, the drone 76 takes a photo of the photovoltaic panel 74 to obtain an image.

[0065] The cleaning operation signal of the drone 76 depends on the image analysis of the attachments on the photovoltaic panel 74 by the drone 76. The drone 76 takes a picture of the photovoltaic panel 74 to obtain an image, for example, by obtaining images of different positions on the photovoltaic panel 74 through at least two camera sensors, and then identifies the degree of dirtiness of the photovoltaic panel 74 according to the grayscale of the image.

[0066] S203 , analyzing the image to determine the position information of the attached objects in the photovoltaic panel 74 .

[0067] After the drone 76 obtains the image of the attachment on the photovoltaic panel 74, it first pre-processes the image, such as removing noise and enhancing contrast, and then extracts the pixel points in the image to analyze the grayscale of the image. The grayscale area indicates the location and size of the attachment, and the grayscale depth indicates the deposition degree of the attachment. After analyzing the image, the drone 76 determines the location information of the attachment in the photovoltaic panel 74, thereby determining the area of ​​the photovoltaic panel 74 that needs to be cleaned.

[0068] S03, adjusting the flight position of the UAV 76 according to the position information.

[0069] The drone 76 determines the position of the drone 76 relative to the photovoltaic panel 74 based on the position of the attachments obtained on the photovoltaic panel 74, and determines the flight altitude based on the area of ​​the attachments and the degree of deposition. If the area of ​​the attachments is large, the drone 76 needs to be raised to a suitable altitude to ensure that the attachments are within the cleaning operation range of the drone 76 to avoid the problem of missed cleaning; if the degree of deposition of the attachments is deep, the drone 76 needs to descend to a suitable altitude. Within the range of ensuring a safe flight altitude, the closer the nozzle 4 on the bracket 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, determining the height of the attachment based on the position information.

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

[0073] S302, determining the flight position of the UAV based on the height of the attachment, the inclination angle between the photovoltaic panel and the horizontal plane, and the preset spraying distance of the nozzle.

[0074] The projection of the drone's flight position on the photovoltaic panel overlaps with the attachments on the photovoltaic panel, and the drone's flight position has a preset flight height relative to the photovoltaic panel, which is determined according to the preset spray distance of the nozzle when the drone cleans the photovoltaic panel, the height of the attachment from the ground, and the inclination angle between the photovoltaic panel and the horizontal plane stored in the drone. For example, for the drone 76 using the water spray mode, the preset flight height of the drone 76 from the photovoltaic panel 74 is divided into one meter to three meters according to the deposition degree of the attachments; for the drone 76 using the wind spray mode, the preset flight height of the drone 76 from the photovoltaic panel 74 is divided into five centimeters to ten centimeters according to the deposition degree of the attachments. If the projection of the drone's flight position on the photovoltaic panel has overlapped with the attachments on the photovoltaic panel, the drone 76 measures its own acceleration at three heights of X, Y, and Z and the angular velocity around three circles, integrates the acceleration to obtain the speed of the drone 76, and integrates the velocity to obtain the displacement of the drone 76. Integrating the angular velocity of the drone 76 obtains the rotation angle of the drone 76, and then obtains the motion posture of the drone 76. Combined with the displacement and attitude of the UAV 76, the current flight altitude and direction of the 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 is used to generate a control output. After accumulating the change of the altitude error over time to eliminate the static error, the rotation speed of the 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 current position of the drone 76 is higher than the preset flight altitude for cleaning the photovoltaic panel 74, for example, when the drone 76 uses the water spray mode, the distance from the photovoltaic panel 74 is higher than three meters, and when the drone 76 uses the wind spray mode, the distance from the photovoltaic panel 74 is higher than eight centimeters. To ensure the cleaning effect of the drone 76, the rotation speed of the rotor 5 of the drone 76 is reduced, the lift of the drone 76 is reduced, and the drone 76 gradually descends to the preset flight altitude. If the current flight altitude is lower than the preset flight altitude, for example, when the drone 76 uses the water spray mode, the distance from the photovoltaic panel 74 is lower than one meter, and when the drone 76 uses the wind spray mode, the distance from the photovoltaic panel 74 is lower than five centimeters. To avoid the drone 76 from colliding with the photovoltaic panel 74 during cleaning, the rotation speed of the rotor 5 of the drone 76 is increased, the lift of the drone 76 is increased, and the drone 76 is gradually raised to the preset flight altitude.

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

[0077] After the drone 76 obtains the inclination angle of the photovoltaic panel 74 and the horizontal plane 75, it opens the brake of the folding arm 2 and adjusts the rotation of the folding arm 2 so that the folding arm 2 is perpendicular to the horizontal plane 75. At this time, the brake of the folding arm 2 is closed and the brake of the bracket 3 is opened. The drone 76 controls the bracket 3 to rotate so that the angle between the bracket 3 and the folding arm 2 and the inclination angle of the photovoltaic panel 74 and the horizontal plane 75 are complementary angles, so 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, that is, the nozzle 4 on the bracket 3 is facing the attachments on the photovoltaic panel 74. After the bracket 3 is parallel to the photovoltaic panel 74, the brake of the bracket 3 is closed. The drone 76 controls the nozzle 4 on the bracket 3 to face the attachments on the photovoltaic panel 74. Considering the nozzle flow rate and the endurance of the drone 76, if the drone 76 uses a 50L water tank, the water consumption of a single nozzle 4 is controlled to be less than or equal to 0.8 liters per second. In order to ensure that the drone 76 has enough cleaning time, at most 4 nozzles 4 are used on the bracket 3.

[0078] S04 includes the following sub-steps:

[0079] S401, obtaining the current angle between the support 3 and the horizontal plane 75;

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

[0081] S402, controlling the folding arm 2 to unfold according to the current angle and inclination angle between the bracket 3 and the horizontal plane 75;

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

[0083] S403, controlling the support 3 to rotate relative to the folding arm 2 until the included angle between the support 3 and the folding arm 2 and the tilt angle are complementary angles.

[0084] When the folding arm 2 is perpendicular to the horizontal plane 75 , the drone 76 opens 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 a complementary angle to the inclination 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, controlling the nozzle 4 to open to clean the attached matter in the photovoltaic panel 74.

[0086] The drone 76 has multiple spray modes. After the drone 76 controls the nozzle 4 to face the photovoltaic panel 74, the drone 76 analyzes the dirtiness level of the attached objects on the photovoltaic panel 74 according to the acquired image of the photovoltaic panel 74. The dirtiness level includes the first level, the second level and the third level. The spray mode is selected according to the dirtiness level. The spray modes include the wind spray mode, the water spray mode and the wind and water mixed spray mode. When the dirtiness level is the first level, the spray mode is the wind spray mode. When the dirtiness level is the second level, the spray mode is the water spray mode. When the dirtiness level is the third level, the spray mode is the wind and water mixed spray mode.

[0087] When the drone 76 is performing cleaning operations, the drone 76 has two motion states: hovering and flying parallel to the photovoltaic panel 74. Under normal operating conditions, the drone 76 controls the rotation speed of the rotor 5 so that the force generated by the rotor 5 is equal to the gravity of the drone 76 itself, so that the drone 76 hovers above the photovoltaic panel 74. For example, based on the height of the drone 76 from the photovoltaic panel 74 and the diameter of the drone 76's own structure, the drone 76 controls the drone 76 to move up and down in a direction perpendicular to the photovoltaic panel 74 so that the range of movement does not exceed 10% of the height of the drone 76 from the photovoltaic panel 74, and the range of movement does not exceed 10% of the diameter of the drone 76's own structure in a direction parallel to the photovoltaic panel 74. This is hovering. If strong winds are encountered, the drone 76 can also remain hovering according to the external wind conditions. The control method steps are as follows:

[0088] S601, obtaining the wind direction and wind force of the external wind.

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

[0090] S602, according to the wind direction and wind force of the external wind, the drone 76 adjusts the rotation of the shaft 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 wind force of the external wind.

[0091] After obtaining the wind direction of the outside wind, the drone 76 controls the rotating shaft 6 of the rotor 5 to flip so that the rotating shaft 6 is parallel to the wind direction, and at the same time controls the rotation speed of the rotor 5 according to the wind force of the outside wind so that the rotor 5 generates a wind force equal to the outside wind, thereby maintaining the drone 76 at a preset flight altitude. At the same time, under strong wind conditions, the drone 76 can choose to increase or decrease the flight altitude to avoid areas with strong winds. It is worth noting that if the wind conditions exceed the handling capacity of the drone 76, the drone 76 will automatically return to the take-off point. When necessary, the drone 76 will find a safe place for emergency landing.

[0092] In addition to strong wind conditions, the drone 76 also dynamically adjusts the rotation speed of the rotor 5 to maintain hovering during cleaning operations. As the drone 76 consumes more water during cleaning operations, the amount of water in the water tank of the drone 76 decreases, and the weight of the drone 76 decreases accordingly. At this time, if the rotor 5 of the drone 76 still runs at the full load speed, it is difficult to ensure the correctness of its working position. Taking this into consideration, the present application has also made improvements in the control method, and its control steps are:

[0093] S701, obtaining the current weight and nozzle flow of the drone 76.

[0094] The current weight of the drone 76 is the weight of the drone 76 itself and the weight of the water contained in the water tank in the drone 76. In the water spray mode, the weight change of the drone 76 is the weight reduction of the drone 76 caused by the reduction of the water volume in the water tank. The drone 76 obtains the nozzle flow rate by measuring the water spray diameter and the water spray time per unit time, thereby determining the water consumption of the water tank. According to the nozzle flow rate, the drone 76 calculates the water consumption of the nozzle 4 to determine the water consumption of the water tank, thereby determining the current weight of the drone 76. As the weight of the drone 76 changes during the cleaning operation, the rotation speed of the drone 76 rotor 5 should also be adjusted accordingly to ensure that the drone 76 hovers.

[0095] S702, reducing the rotation speed of the rotor 5 according to the weight of the UAV 76 and the nozzle flow rate, so as to keep the UAV 76 hovering.

[0096] When the weight of the drone 76 is reduced, the water consumption of the drone 76 at the next moment is predicted according to the flow rate of the nozzle 4, and the weight of the drone 76 at the next moment is calculated. The rotation speed of the rotor 5 of the drone 76 is adjusted according to the weight of the drone 76 at the next moment, and the rotation speed of the rotor 5 is reduced to ensure that the drone 76 will not exceed the predetermined flight altitude as the water consumption increases, and keep hovering.

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

[0098] L=1 / 2×ρ×V 2 ×S×C L

[0099] Where: L-lift (Newton), ρ-air density (kilograms per cubic meter), V-flight speed of the drone 76 relative to the air (meters per second), S-area swept by the rotor 5 when rotating (square meters), C L - lift coefficient (dimensionless coefficient, depending on the shape and attitude of the rotor 5).

[0100] The weight calculation formula of UAV 76 is as follows:

[0101] W=EW+PL

[0102] In the formula: W is the weight of UAV 76, EW is the empty weight of UAV 76 (the weight of the structure and equipment of UAV 76 itself), PL is the payload of UAV 76 (mainly the weight of the water carried in the water tank).

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

[0104] To maintain stable flight, the lift of the drone 76 must be equal to the weight of the drone 76, that is, L = W. During the cleaning operation, the drone 76 continuously calculates and adjusts the rotation 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 the water consumption increases and remains hovering.

[0105] There are two working paths for the drone 76 to fly parallel to the photovoltaic panel 74, see Figure 3 , is the first working path 73 of the drone 76. After receiving the destination position 72, the drone 76 reaches the destination position 72 from the current position 71 parallel to the photovoltaic panel 74. The control method of the first working path 73 is:

[0106] S801 , obtaining the inclination 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 plane 75, detects the boundaries of the photovoltaic panel 74 and the boundaries of the horizontal plane 75, extracts feature points, and forms a stereoscopic vision of the photovoltaic panel 74 and the horizontal plane 75 based on the extracted feature points, thereby determining the inclination angle of the photovoltaic panel 74 and the horizontal plane 75. According to the acquired inclination angle of the photovoltaic panel 74 and the horizontal plane 75, the inclination angle of the drone 76 bracket 3 is adjusted to ensure that the gas or liquid sprayed by the nozzle 4 during the cleaning operation of the drone 76 impacts the photovoltaic panel 74 at a better angle, thereby efficiently cleaning the photovoltaic panel 74.

[0108] S802, obtaining the position of the drone 76.

[0109] The drone 76 measures its own acceleration at three heights, X, Y, and Z, and the angular velocity around three circles, integrates the acceleration to obtain the velocity of the drone 76, and integrates the velocity to obtain the displacement of the drone 76. The angular velocity of the drone 76 is integrated to obtain the rotation angle of the drone 76, and then the motion attitude of the drone 76, such as the pitch angle of the drone 76, is obtained. At the same time, the drone 76 measures the strength and direction of the earth's magnetic field to provide an absolute reference direction. Combined with the displacement, attitude, and reference direction of the drone 76, the position and orientation of the drone 76 are determined so that the drone 76 can be navigated and motion controlled.

[0110] S803, receiving the location of the flight destination of the drone 76.

[0111] The flight destination position 72 of the first working path of the drone 76 is a set value, and the drone 76 receives communication through the mobile network.

[0112] S804, determining the flight path of the drone 76 according to the inclination angle of the photovoltaic panel 74 and the horizontal plane 75, the position of the drone 76, and the flight destination 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 the movement posture, movement direction and rotation speed of the rotor 5 according to the current position 71, the destination position 72 and the inclination angle of the photovoltaic panel 74 and the horizontal plane 75, so that the drone 76 reaches the destination position 72 from the current position 71 parallel to the photovoltaic panel 74 to ensure the cleaning effect of the drone 76.

[0114] See also Figure 4 , which is the second working path 78 of 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. Cleaning from top to bottom parallel to the photovoltaic panel 74 avoids residual water marks after cleaning. The control method of the second working path 78 is:

[0115] S901 , obtaining a 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 acquired image of the photovoltaic panel 74 , and provides a direction reference for the working path of the photovoltaic panel 74 .

[0117] S902 , adjusting the angle of the rotating shaft 6 of the rotor 5 and the height direction and adjusting the rotation speed of the rotor 5 according to the first boundary 77 , so that the flight path of the UAV 76 is parallel to the first boundary 77 .

[0118] The drone 76 starts from 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, the drone 76 adjusts the angle of the rotating shaft 6 and the height direction of the rotor 5 and the rotation speed of the rotor 5, and flies from one end of the first boundary 77 of the photovoltaic panel 74 to the other end of the first boundary 77, so that the flight path of the drone 76 is parallel to the first boundary 77, that is, the drone 76 cleans parallel to the photovoltaic panel 74. When the drone 76 reaches the end point from the starting point of the first boundary 77, it moves to a new starting point that is one body length away from the starting point of the first boundary 77 to perform cleaning again, and then repeats until the cleaning is completed, ensuring that the drone 76 cleans more thoroughly.

[0119] There are two modes of passive control and automatic control for the drone 76 to reach the photovoltaic panel 74 from the take-off point. Figure 5 , which is the passive control mode of the drone 76. In this mode, the operator controls the drone 76 to fly above the photovoltaic panel 74 through the main console or remote control, so that the drone 76 can carry out cleaning operations. Figure 6 , which 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 the flight path to fly above the photovoltaic panel 74 to perform cleaning operations.

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

[0121] The drone 76 includes a fuselage 1, a folding arm 2 and a bracket 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 bracket 3. The bracket 3 is provided with a nozzle 4.

[0122] Before the drone 76 cleans the photovoltaic panel 74, it first determines the location, area and degree of deposition of the attached objects on the photovoltaic panel 74, so as to determine the relative position of the drone 76 to the photovoltaic panel 74 and the spray mode of the drone 76, so as to ensure that the drone 76 can accurately and efficiently clean the attached objects on the photovoltaic panel 74, such as floating dust and dirt. If there is only floating dust or a small amount of dirt on the photovoltaic panel 74, which is light in weight and easily blown away from the light-receiving surface of the photovoltaic panel 74, the drone 76 selects the wind spray mode; if there is a lot of dirt on the photovoltaic panel 74, and it is difficult to clean it thoroughly with the wind spray mode alone, the drone 76 selects the water spray mode, which has a larger water mist impact force and is convenient for removing large-area and deep-deposited dirt.

[0123] The drone 76 determines the position of the drone 76 relative to the photovoltaic panel 74 according to the obtained position of the attachment on the photovoltaic panel 74, and determines the preset flight altitude of the drone according to the area of ​​the attachment, the deposition degree of the attachment, the height of the attachment from the ground, the inclination angle between the photovoltaic panel and the horizontal plane, and the preset spray distance of the nozzle. For example, if the area of ​​the attachment is large, the drone 76 needs to be raised to a suitable height to ensure that the attachment is within the cleaning operation range of the drone 76 to avoid the problem of missed cleaning; if the deposition degree of the attachment is deep, the drone 76 needs to be lowered to a suitable height. Within the range of ensuring a safe flight altitude, the closer the nozzle 4 on the bracket 3 of the drone 76 is to the photovoltaic panel 74, the higher the cleaning efficiency of the drone 76.

[0124] After the drone 76 acquires the images of the photovoltaic panel 74 and the horizontal plane 75, it detects the boundaries of the photovoltaic panel 74 and the horizontal plane 75, extracts feature points, and forms a stereoscopic vision of the photovoltaic panel 74 and the horizontal plane 75 based on the extracted feature points, thereby determining the inclination angle of the photovoltaic panel 74 and the horizontal plane 75. According to the acquired inclination angle of the photovoltaic panel 74 and the horizontal plane 75, the inclination angle of the bracket 3 of the drone 76 is adjusted to ensure that the gas or liquid ejected from the nozzle 4 during the cleaning operation of the drone 76 impacts the photovoltaic panel 74 at a better angle, thereby efficiently cleaning the photovoltaic panel 74.

[0125] After the drone 76 obtains the inclination angle of the photovoltaic panel 74 and the horizontal plane 75, the brake of the folding arm 2 of the drone 76 is turned on, and the rotation of the folding arm 2 is adjusted so that the folding arm 2 is perpendicular to the horizontal plane 75. At this time, the brake of the folding arm 2 is turned off and the brake of the bracket 3 is turned on. The drone 76 controls the bracket 3 to rotate so that the angle between the bracket 3 and the folding arm 2 and the inclination angle of the photovoltaic panel 74 and the horizontal plane 75 are complementary angles, so 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, that is, the nozzle 4 on the bracket 3 is facing the attachment in the photovoltaic panel 74. After the bracket 3 is parallel to the photovoltaic panel 74, the brake of the bracket 3 is turned off. The drone 76 controls the nozzle 4 on the bracket 3 to face the attachment in the photovoltaic panel 74. Considering the flow rate of the nozzle 4 and the endurance of the drone 76, if the drone 76 uses a 50L water tank, the water consumption of a single nozzle 4 is controlled to be less than or equal to 0.8 liters per second. In order to ensure that the drone 76 has enough cleaning time, at most 4 nozzles 4 are used on the bracket 3.

[0126] The drone 76 also has a variety of spray modes. After the drone 76 controls the nozzle to face the photovoltaic panel 74, it analyzes the dirtiness level of the attached objects on the photovoltaic panel 74 according to the image of the photovoltaic panel 74 obtained. The dirtiness level includes the first level, the second level and the third level. The spray mode is selected according to the dirtiness level. The spray modes include wind spray mode, water spray mode and wind and water mixed spray mode. When the dirtiness level is the first level, the spray mode is the wind spray mode. When the dirtiness level is the second level, the spray mode is the water spray mode. When the dirtiness level is the third level, the spray mode is the wind and water mixed spray mode. After the drone 76 obtains the position and image information of the attached objects on the photovoltaic panel 74, it controls the drone 76 to hover at a suitable cleaning operation height from the photovoltaic panel 74, controls the bracket to be parallel to the photovoltaic panel, controls the nozzle to face the attached objects in the photovoltaic panel, and adopts the corresponding spray mode for different images of attached objects, so as to ensure that the drone cleans the attached objects in the photovoltaic panel at a suitable height and a suitable angle, so that the drone cleans more cleanly and the cleaning range is more comprehensive.

[0127] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0128] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0129] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0130] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0131] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for cleaning photovoltaic panels based on drones, characterized in that: The drone comprises a fuselage, a folding arm and a bracket, wherein the fuselage is rotatably connected to one end of the folding arm, an end of the folding arm away from the fuselage is rotatably connected to the bracket, and the bracket is provided with a nozzle, and the control method comprises: Get the tilt angle between the photovoltaic panel and the horizontal plane; Obtaining location information of objects attached to photovoltaic panels; adjusting the flight position of the UAV according to the position information; Controlling the folding arm of the drone to unfold 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; The nozzle is controlled to open to clean the attached objects in the photovoltaic panel.

2. The control method according to claim 1, characterized in that: The step of obtaining the location information of the attachments on the photovoltaic panel includes: Receiving a position signal of a photovoltaic panel and flying above the photovoltaic panel according to the position signal; Taking a picture of the photovoltaic panel to obtain an image; The image is analyzed to determine location information of objects attached to the photovoltaic panel.

3. The control method according to claim 1, characterized in that: The UAV further includes a rotor, and a rotating shaft of the rotor is hinged to the fuselage; and adjusting the flight position of the UAV according to the position information includes: determining a height of the attachment based on the position information; The flight position of the UAV is determined based on the height of the attachment, the inclination angle of the photovoltaic panel and the horizontal plane, and the preset spraying distance of the nozzle.

4. The control method according to claim 3, characterized in that: The controlling the folding arm of the drone to unfold according to the tilt angle so that the bracket is parallel to the photovoltaic panel comprises: Obtaining a current angle between the support and a horizontal plane; Controlling the folding arm to unfold according to the current angle between the bracket and the horizontal plane and the tilt angle; The support is controlled to rotate relative to the folding arm until the angle between the support and the horizontal plane is complementary to the tilt angle.

5. The control method according to claim 4, characterized in that: When the nozzle is controlled to be turned on to clean the photovoltaic panel, the drone is kept hovering; the drone is kept hovering including: Get the wind direction and wind force of the outside wind; The rotation of the rotating shaft relative to the fuselage is adjusted according to the wind direction and wind force of the external wind, and the rotation speed of the rotor is adjusted to balance the wind force generated by the rotor with the wind force of the external wind.

6. The control method according to claim 4, characterized in that: The control method further includes the UAV adjusting the rotor speed according to the weight of the UAV so that the UAV keeps hovering; the adjusting the rotor speed according to the weight of the UAV so that the UAV keeps hovering includes: Get the current drone weight and nozzle flow rate; The rotation speed of the rotor is reduced according to the weight of the UAV and the nozzle flow rate, so that the UAV can maintain hovering.

7. The control method according to claim 4, characterized in that: When the nozzle is controlled to be turned on to clean the photovoltaic panel, the drone is controlled to fly parallel to the photovoltaic panel; The controlling the drone to fly parallel to the photovoltaic panel comprises: Obtaining the inclination angle between the photovoltaic panel and the horizontal plane; Obtaining the location of the drone; Receiving the location of the flight destination of the drone; The flight path of the drone is determined according to the inclination angle between the photovoltaic panel and the horizontal plane, the position of the drone, and the position of the flight destination of the drone, so that the flight path of the drone is parallel to the photovoltaic panel.

8. The control method according to claim 7, characterized in that: The controlling the drone to fly parallel to the photovoltaic panel also includes: Get the first boundary of the photovoltaic panel; The angle between the rotor shaft and the height direction and the rotor speed are adjusted according to the first boundary, so that the flight path of the UAV is parallel to the first boundary.

9. The control method according to claim 1, characterized in that: The drone has multiple jet modes; The controlling the nozzle to open to clean the photovoltaic panel includes: Determine the dirtiness level according to the image of the attachment, and the dirtiness level includes the first level, the second level and the third level; Select the spray mode according to the degree of dirtiness. The spray modes include wind spray mode, water spray mode, and wind and water mixed spray mode; When the dirtiness level is the first level, the spray mode is the wind spray mode; When the dirtiness level is the second level, the spray mode is a water spray mode; When the dirtiness level is the third level, the spray mode is a wind and water mixed spray mode.

10. A drone, characterized in that: The drone cleans the photovoltaic panels using the control method described in any one of claims 1-9.

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