WO2020189620A1 - Cleaning device, cleaning system for solar photovoltaic devices, and cleaning method for solar photovoltaic devices - Google Patents

Abstract

The invention is provided with: a body that can move along a surface to be cleaned; a wiper that is installed on the body in contact with the surface to be cleaned and that has a material for adsorbing dirt on the surface to be cleaned; a first sensor that is installed facing the surface to be cleaned at the front of the body in the direction of motion and that detects dirt on the surface to be cleaned; a second sensor that is installed facing the surface to be cleaned at the rear of the body in the direction of motion and that detects, on the side opposite to the first sensor as seen from the wiper, dirt on the surface to be cleaned; and a control unit that controls motion of the body along the surface to be cleaned. While the body is moving, the control unit controls the direction of motion of the body so that motion continues when the level of dirt detected by the second sensor is lower than a designated level and so that the same location is passed over again when the detected level is higher than the designated level.

Description

Cleaning equipment, photovoltaic power generation equipment cleaning system, and photovoltaic power generation equipment cleaning method

The present invention relates to a cleaning device, a cleaning system for a photovoltaic power generation device, and a cleaning method for the photovoltaic power generation device.
This application claims priority based on Japanese Application No. 2019-049450 filed on March 18, 2019, and incorporates all the contents described in the Japanese application.

The surface of the array (panel) of the photovoltaic power generation device may be contaminated with sand or the like. In areas with heavy rain, the rain may naturally wash away dirt, but in areas with low rain, sand accumulates. If the sand is left unclean, the power generation efficiency will decrease, so regular cleaning work will be required. Conventionally, cleaning is mainly performed manually, but since labor costs are high, a cleaning device has also been proposed (see, for example, Patent Document 1 and Patent Document 2).

Japanese Unexamined Patent Publication No. 2013-221473 US Patent Application Publication US2014 / 0041138 A1

The present disclosure includes the following inventions. However, the present invention is defined by the claims.

The cleaning device of the present disclosure is a cleaning device that cleans a surface to be cleaned, and is mounted on the body in a state of being in contact with the surface to be cleaned and a body that can move along the surface to be cleaned. A wiper having a material that adsorbs dirt adhering to the cleaning target surface, a first sensor mounted in front of the body in the moving direction in a state of facing the cleaning target surface, and detecting dirt on the cleaning target surface, and the cleaning target. A second sensor, which is mounted rearward in the moving direction of the body while facing the surface, is on the opposite side of the first sensor when viewed from the wiper, and detects dirt on the surface to be cleaned, and the cleaning target. A control unit that controls the movement of the body along a surface is provided, and the control unit moves the body when the level of dirt detected by the second sensor is lower than a predetermined level during the movement of the body. It is a cleaning device that controls the moving direction of the body so as to continue and pass through the same place again when the level is higher than the predetermined level.
In addition, adsorption also includes gathering (the same shall apply hereinafter).

The cleaning system of the present disclosure is a photovoltaic power generation device having an array and a photovoltaic power generation device including a photovoltaic power generation device for cleaning the light receiving surface of the array, and the cleaning device is the light receiving surface. A body that can move along the light-receiving surface, a wiper that is mounted on the body in contact with the light-receiving surface and has a material that adsorbs dirt adhering to the light-receiving surface, and a body that faces the light-receiving surface. The first sensor mounted in the front in the direction to detect the dirt on the light receiving surface and the first sensor mounted in the rear in the moving direction of the body facing the light receiving surface are opposite to the first sensor when viewed from the wiper. On the side, a second sensor that detects dirt on the light receiving surface and a control unit that controls the movement of the body along the light receiving surface are provided, and the control unit is provided during the movement of the body. When the level of dirt detected by the second sensor is lower than the predetermined level, the movement is continued, and when the level is higher than the predetermined level, the movement direction of the body is controlled so as to pass through the same place again. Cleaning system.

Further, the cleaning system of the present disclosure is a cleaning system for a solar power generation device capable of directing the light receiving surface of the array to the ground, and solar power generation in a state where the light receiving surface of the array is oriented horizontally and facing the ground. A device, a vehicle parked below the array, a lifting device mounted on the vehicle that can expand and contract in the vertical direction, and a lifting device that can move horizontally on the upper surface of the lifting device to clean the light receiving surface. The cleaning device includes a body that can move along the light receiving surface and a material that is mounted on the body in contact with the light receiving surface and adsorbs dirt adhering to the light receiving surface. A wiper to be mounted, a first sensor mounted on the front in the moving direction of the body in a state of facing the light receiving surface and detecting dirt on the light receiving surface, and a first sensor in the moving direction of the body facing the light receiving surface. A second sensor mounted rearward and opposite to the first sensor when viewed from the wiper to detect dirt on the light receiving surface, and a control unit that controls movement of the body along the light receiving surface. When the level of dirt detected by the second sensor is lower than the predetermined level, the control unit continues the movement while the body is moving, and when the level is higher than the predetermined level, the control unit relocates to the same place. It is a cleaning system of a solar power generation device that controls the moving direction of the body so as to pass through.

On the other hand, in the cleaning method of the present disclosure, a cleaning device having a wiper made of microfiber is used to clean the light receiving surfaces of a plurality of solar power generation devices installed apart from each other. In the method, with the cleaning device mounted on a hoverable flying object, the cleaning device is approached to an arbitrary solar power generation device, the cleaning device is attached to a predetermined position on the light receiving surface, and the cleaning device is said. Clean with a dry wipe by moving along the light receiving surface, check the cleaning result, and if the cleaning result is not good, pass through the same place multiple times to execute the cleaning work, and when the cleaning is completed, the above The flying object is a cleaning method for a solar power generation device, in which a plurality of solar power generation devices are cleaned by repeating the process of transporting the cleaning device to another uncleaned solar power generation device in the air.

FIG. 1 is a perspective view of an example of a concentrating type photovoltaic power generation device for one unit as viewed from the light receiving surface side, and shows the photovoltaic power generation device in a completed state. FIG. 2 is a perspective view of an example of a concentrating type photovoltaic power generation device for one unit as viewed from the light receiving surface side, and shows the photovoltaic power generation device in a state during assembly. FIG. 3 is an example of a graph showing how the particle size of the sand collected from the ground (left) and the sand deposited after being blown up by the wind (right) are different. FIG. 4 is a diagram showing an outline of the mechanical configuration of the cleaning device. FIG. 5 is a diagram showing an outline of a control configuration of the cleaning device. FIG. 6A is a diagram showing a state of light reception and reception of the optical sensor on a clean surface to be cleaned. FIG. 6B is a diagram showing a state of light reception and reception of the optical sensor on the surface to be cleaned to which dirt is attached. FIG. 7 is a comparative photograph showing the difference in the fiber structure of the wiper. FIG. 8 is a photograph showing a state in which sand is adsorbed on the microfiber, and an enlarged view of the central portion of the photograph of (a) is a photograph of (b). FIG. 9 is a diagram showing an example of a state in which the light receiving surface of the array of the photovoltaic power generation device is cleaned by using the cleaning device. FIG. 10 is an example of a flowchart showing processing by the control unit from the start to the end of cleaning by the cleaning device. FIG. 11 is a diagram showing an outline of the mechanical configuration of the cleaning device as in FIG. 4, but the difference from FIG. 4 is a diagram when there is a protrusion as a step on the surface to be cleaned. FIG. 12 is a diagram showing an example of a state in which the light receiving surface of the array of the photovoltaic power generation device is cleaned by using the cleaning device connected to the flying object (drone). FIG. 13 is a diagram showing another example of a state in which the light receiving surface of the array of the photovoltaic power generation device is cleaned by using the cleaning device connected to the flying object. FIG. 14 is a diagram showing an example of a state in which the light receiving surface of the array of the photovoltaic power generation device is cleaned by using the cleaning device mounted on the vehicle. FIG. 15 is a schematic view showing a state of sand cleaning with a microfiber cloth. FIG. 16 is a graph examining how the output (generated power) of the array changes under the same weather conditions when the conditions of the wiper pressing pressure are changed in the presence of a certain amount of sand. FIG. 17 is a diagram showing a state in which an array is imaged using an air vehicle. FIG. 18 is a diagram showing an example of a dirt determination system mounted on an air vehicle.

[Issues to be solved by this disclosure]
In dry highlands where water resources are scarce, it is difficult to secure water for washing and manage water storage. If you sprinkle an insufficient amount of water and rub it with a cleaning device, the dirt may spread and the surface may be scratched.

In view of such a problem, an object of the present disclosure is to provide a cleaning device that can remove stains without water, a cleaning system for a photovoltaic power generation device, and a cleaning method for the photovoltaic power generation device.

[Effect of the present disclosure]
According to the present disclosure, it is possible to provide a cleaning device that can remove stains without water, a cleaning system for a photovoltaic power generation device, and a cleaning method for the photovoltaic power generation device.

[Explanation of Embodiments of the present disclosure]
The embodiments of the present disclosure include at least the following as a gist thereof.

(1) This is a cleaning device for cleaning the surface to be cleaned, and is mounted on the body in contact with the surface to be cleaned and a body that can move along the surface to be cleaned, and is mounted on the surface to be cleaned. A wiper having a material that adsorbs the adhered dirt, a first sensor mounted in front of the body in the moving direction while facing the cleaning target surface, and detecting dirt on the cleaning target surface, and the cleaning target surface. A second sensor, which is mounted rearward in the moving direction of the body in a state of facing the body, is on the opposite side of the first sensor when viewed from the wiper, and detects dirt on the surface to be cleaned, and the surface to be cleaned. The control unit includes a control unit that controls the movement of the body along the body, and the control unit continues the movement when the level of dirt detected by the second sensor is lower than a predetermined level during the movement of the body. It is a cleaning device that controls the moving direction of the body so as to pass through the same place again when the level is higher than the predetermined level.

In such a cleaning device, the dirt adhering to the surface to be cleaned is removed by the wiper by moving the body. When the level of dirt detected by the second sensor behind in the moving direction during the movement of the body is lower than a predetermined level, the cleaning result is good and the body moves as it is. On the other hand, when the level of dirt detected by the second sensor is higher than a predetermined level, control is performed so as to pass through the same place again, and at least "wiping twice" is performed. In this way, the dirt can be wiped a plurality of times, and more reliable cleaning can be performed. In addition, since the wiper has a material that adsorbs dirt, it can be wiped dry without using water. Since no water is used, a water supply device is not required and the entire device is simplified.

(2) For example, in (1), the dirt contains sand, and the material is microfiber.
Since the microfiber sucks up minute sand with static electricity, dirt can be removed without using water, and it is possible to prevent the surface to be cleaned from being scratched by the wiper.

(3) In (1) or (2), both the first sensor and the second sensor are optical sensors, and the level of dirt can be detected based on the intensity of reflected light.
The amount of light scattered differs depending on the degree of dirt (adhesion amount) on the surface to be cleaned, and the intensity of reflected light differs. Based on this, the level of dirt can be detected based on the intensity of the reflected light detected by the optical sensor.

(4) In any of the cleaning devices (1) to (3), for example, the wiper has a first roller for initial cleaning that rolls on the surface to be cleaned due to the movement of the body, and the first roller. A second roller for finish cleaning, which is located behind the roller in the moving direction and rolls on the cleaning target surface due to the movement of the body, is provided.
In this case, the first roller and the subsequent second roller arranged in the front-rear direction in the moving direction roll on the surface to be cleaned, so that initial cleaning and finish cleaning can be performed, respectively.

(5) In any of the cleaning devices (1) to (4), the dirt level detected by the first sensor and the dirt level detected by the second sensor are both from the first predetermined value. When the difference between the two levels is smaller than the second predetermined value indicating that the wiper is minute, the control unit determines that it is time to replace the wiper.
When the wiper becomes dirty, this happens, so you can know when to replace the wiper without looking directly at it.

(6) The cleaning device according to any one of (1) to (5) may be provided with an elastic member that pushes the wiper out of the body so that the wiper is in pressure contact with the surface to be cleaned.
In this case, the wiper can be stably pressed against the cleaning target surface even if the cleaning target surface has some irregularities.

(7) In any of the cleaning devices (1) to (6), for example, the surface to be cleaned is a light receiving surface in an array of photovoltaic power generation devices.
Fine sand is particularly likely to adhere to the array of photovoltaic power plants installed in dry highlands. The cleaning device is suitable for removing such fine sand stains.

(8) In any of the cleaning devices (1) to (7), a camera may be mounted on an end portion of the body so as to face the surface to be cleaned.
In this case, it is possible to detect that the body has moved to the end of the surface to be cleaned based on the actually measured image information captured by the camera.

(9) In any of the cleaning devices (1) to (8), a hoverable flying object may be attached to the body.
In this case, even a cleaning device in a posture that is likely to fall due to gravity can be supported by the flying object. An air vehicle is, for example, a so-called drone.

(10) In any of the cleaning devices (1) to (9), the pressing pressure for pressing the wiper against the surface to be cleaned is preferably in the range of 500 Pa to 5000 Pa.
If the pressing pressure is less than 500 Pa, a sufficient cleaning effect cannot be obtained. If the pressing pressure exceeds 5000 Pa, the surface to be cleaned may be damaged. By setting the pressing pressure within the range of 500 Pa to 5000 Pa, it is possible to suppress damage to the surface to be cleaned while ensuring the cleaning effect.

(11) Further, this is a cleaning system of a photovoltaic power generation device including a photovoltaic power generation device having an array and a cleaning device for cleaning the light receiving surface of the array, and the cleaning device is the light receiving device. A body that can move along the surface, a wiper that is mounted on the body in contact with the light receiving surface and has a material that adsorbs dirt adhering to the light receiving surface, and a body that faces the light receiving surface. The first sensor mounted in the front in the moving direction and detecting the dirt on the light receiving surface, and the first sensor mounted in the rear in the moving direction of the body in a state facing the light receiving surface and viewed from the wiper. On the opposite side, a second sensor for detecting dirt on the light receiving surface and a control unit for controlling the movement of the body along the light receiving surface are provided.
During the movement of the body, the control unit continues the movement when the level of dirt detected by the second sensor is lower than the predetermined level, and when the level is higher than the predetermined level, the body passes through the same place again. It is a cleaning system for photovoltaic power generation equipment that controls the direction of movement.

In the cleaning device in such a cleaning system of the photovoltaic power generation device, the dirt adhering to the light receiving surface is removed by the wiper by moving the body. When the level of dirt detected by the second sensor behind in the moving direction during the movement of the body is lower than a predetermined level, the cleaning result is good and the body moves as it is. On the other hand, when the level of dirt detected by the second sensor is higher than a predetermined level, control is performed so as to pass through the same place again, and at least "wiping twice" is performed. In this way, the dirt can be wiped a plurality of times, and more reliable cleaning can be performed. In addition, since the wiper has a material that adsorbs dirt, it can be wiped dry without using water. Since no water is used, a water supply device is not required and the entire device is simplified.

(12) The cleaning system for the photovoltaic power generation device according to (11) includes a hoverable flying object equipped with an imaging device, and the flying object includes an area of dirt with respect to the total area of the light receiving surface of the imaged array. The array to be cleaned by the cleaning device may be determined based on the ratio of.
In this case, the array to be cleaned can be accurately detected in advance.

(13) Further, this is a cleaning system for a solar power generation device capable of directing the light receiving surface of the array to the ground, and the solar power generation device in a state where the light receiving surface of the array is oriented horizontally and facing the ground. A vehicle parked below the array, a lifting device mounted on the vehicle that can expand and contract in the vertical direction, and a lifting device that can move horizontally on the upper surface of the lifting device to clean the light receiving surface. A cleaning device is provided, and the cleaning device has a body that can move along the light receiving surface and a material that is mounted on the body in contact with the light receiving surface and adsorbs dirt adhering to the light receiving surface. A wiper, a first sensor mounted in front of the body in the moving direction while facing the light receiving surface, and a first sensor for detecting dirt on the light receiving surface, and a rear sensor in the moving direction of the body facing the light receiving surface. A second sensor that is mounted on the wiper and is on the opposite side of the first sensor to detect dirt on the light receiving surface, and a control unit that controls the movement of the body along the light receiving surface. When the level of dirt detected by the second sensor is lower than a predetermined level, the control unit continues the movement while the body is moving, and when the level is higher than the predetermined level, the control unit passes through the same place again. This is a cleaning system for a solar power generation device that controls the moving direction of the body.

In the cleaning device in such a cleaning system of the photovoltaic power generation device, the dirt adhering to the light receiving surface is removed by the wiper by moving the body. When the level of dirt detected by the second sensor behind in the moving direction during the movement of the body is lower than a predetermined level, the cleaning result is good and the body moves as it is. On the other hand, when the level of dirt detected by the second sensor is higher than a predetermined level, control is performed so as to pass through the same place again, and at least "wiping twice" is performed. In this way, the dirt can be wiped a plurality of times, and more reliable cleaning can be performed. In addition, since the wiper has a material that adsorbs dirt, it can be wiped dry without using water. Since no water is used, a water supply device is not required and the entire device is simplified. Once the cleaning of one photovoltaic device is complete, the vehicle can move to another photovoltaic device and perform similar cleaning.

(14) Further, this is a cleaning method for a solar power generation device, which uses a cleaning device having a wiper made of microfiber to clean the light receiving surfaces of a plurality of solar power generation devices installed apart from each other. In a state where the cleaning device is mounted on a hoverable flying object, the cleaning device is approached to an arbitrary solar power generation device, the cleaning device is attached to a predetermined position on the light receiving surface, and the cleaning device receives the light. Clean with a dry wipe by moving along the surface, check the cleaning result, and if the cleaning result is not good, pass the same place multiple times to perform the cleaning work, and when the cleaning is completed, the flight The body is a cleaning method for a solar power generation device, in which a plurality of solar power generation devices are cleaned by repeating the process of transporting the cleaning device to another uncleaned solar power generation device in the air.

In this case, first, the cleaning device is attached to a predetermined position on the light receiving surface of an arbitrary photovoltaic power generation device by the flying object, and then the light receiving surface is cleaned by dry wiping by moving the cleaning device. Then, the cleaning result is checked, and if the cleaning result is not good, the same place is passed a plurality of times to execute the cleaning work. In this way, dirt on the light receiving surface can be wiped multiple times, and more reliable cleaning can be performed. In addition, since it is a dry wipe, no water is used, no water supply device is required, and the entire device is simplified. If the flying object carries the cleaning devices in the air one after another to the plurality of photovoltaic power generation devices, the cleaning of the plurality of photovoltaic power generation devices can be performed by one cleaning device.

[Details of Embodiments of the present disclosure]
Hereinafter, specific examples of the cleaning device or cleaning system of the present disclosure will be described with reference to the drawings. First, a photovoltaic power generation device, which is a typical example of the application target of the cleaning device, will be described.

<< Main configuration of photovoltaic power generation equipment >>
1 and 2 are perspective views of an example of a concentrating photovoltaic power generation device for one unit as viewed from the light receiving surface side. FIG. 1 shows a photovoltaic power generation device 100 in a completed state, and FIG. 2 shows a photovoltaic power generation device 100 in a state in the middle of assembly. FIG. 2 shows a state in which the skeleton of the tracking gantry 25 can be seen in the right half, and a state in which a concentrating photovoltaic power generation module (hereinafter, also simply referred to as a module) 1M is attached in the left half. When actually attaching the module 1M to the tracking pedestal 25, the tracking pedestal 25 is attached while lying on the ground.

In FIG. 1, the photovoltaic power generation device 100 includes an array (photovoltaic power generation panel) 1 which is continuous on the upper side and is divided into left and right on the lower side to form a planar light receiving surface as a whole, and a support mechanism 2 thereof. I have. The array 1 is configured by arranging the modules 1M on the tracking pedestal 25 (FIG. 2) on the back side. In the example of FIG. 1, the array 1 is an aggregate of 200 modules 1M in total, consisting of (96 (= 12 × 8) × 2) pieces constituting the left and right wings and 8 pieces in the central crossover portion. It is configured. In the module 1M, a known configuration in which optical systems that collect sunlight and guide it to a power generation element are arranged in a matrix is mounted.

The support mechanism 2 includes a support column 21, a foundation 22, a drive unit 23, a horizontal axis 24 (FIG. 2) as a drive axis, and a tracking mount 25. The lower end of the support column 21 is fixed to the foundation 22, and the upper end is provided with a drive unit 23.

In FIG. 1, the foundation 22 is firmly buried in the ground so that only the upper surface can be seen. With the foundation 22 buried in the ground, the columns 21 are vertical and the horizontal axis 24 (FIG. 2) is horizontal. The drive unit 23 can rotate the horizontal axis 24 in two directions, an azimuth angle (an angle centered on the support column 21) and an elevation angle (an angle centered on the horizontal axis 24). In FIG. 2, a reinforcing member 25a for reinforcing the tracking mount 25 is attached to the horizontal shaft 24. Further, a plurality of horizontal rails 25b are attached to the reinforcing member 25a. Module 1M is mounted so as to fit into this rail. If the horizontal axis 24 rotates in the direction of the azimuth or elevation, the array 1 also rotates in that direction.

Array 1 is usually vertical as shown in FIG. 1 before dawn and sunset.
During the daytime, the drive unit 23 operates so that the light receiving surface of the array 1 always faces the sun, and the array 1 performs the tracking operation of the sun.

《Sand and microfiber adhering to the array》
FIG. 3 is an example of a graph showing how the particle size of the sand collected from the ground (left) and the sand deposited after being blown up by the wind (right) are different. The measured location is Ouarzazate, Morocco. The horizontal axis represents the particle size [μm], and the vertical axis represents the percentage [%] contained. The curve in the graph shows the cumulative percentage [%] from the smallest particle size. Naturally, the total amount is 100%.

The centriole of the proportion of sand collected from the ground was 178 [μm]. On the other hand, the central particle size of the sand that was rolled up and deposited by the wind was 46.8 [μm]. That is, it can be seen that the sand that has been rolled up and deposited by the wind is finer sand with a smaller particle size than the sand collected from the ground. It was found that microfiber cloth, which is a cloth material made of microfiber, is suitable for removing such fine sand. Compared to other fiber cloths used for cleaning, the microfiber cloth has more fiber gaps and can adsorb dirt by static electricity. Therefore, no water is required to adsorb the sand.

FIG. 15 is a schematic view showing a state of sand cleaning with a microfiber cloth. Assuming the cross section of the microfiber cloth, the closer to the surface, the more the aggregates of fibers are split apart. Therefore, as shown on the right side of FIG. 15, the protrusion-shaped fibers are randomly present. The individual size of the fibers is about 5 μm. When such a microfiber cloth is moved in the cleaning direction, a part of sand (fine sand) is trapped in the gap between the fibers, but most of the sand is gathered together. The collected sand is extruded from the light receiving surface 1f of the array 1.

<< Example of cleaning device >>
FIG. 4 is a diagram showing an outline of the mechanical configuration of the cleaning device 200. In the figure, the cleaning device 200 is like a self-propelled traveling robot, and has a body 201 as a moving body. The body 201 is movable along the surface to be cleaned. The material of the body 201 may be metal, but resin is preferable for weight reduction. Further, a resin that does not easily deteriorate with ultraviolet rays is preferable. Let X, Y, and Z be the three orthogonal directions in FIG.

The body 201 can freely move in the X direction of FIG. 4 as a normal moving direction, and is provided with drive units 202 in front of and behind the X direction. The drive unit 202 is specifically a wheel and a drive mechanism (motor or the like) thereof, and the wheels are, for example, four wheels. The body 201 can also move in the backward (−X) direction. Further, in the drive unit 202, the front wheels or the rear wheels are steering wheels, and lateral movement (change of travel path) in the Z direction (or −Z direction) is also possible. The wheels of the drive unit 202 preferably have adhesion to the surface F to be cleaned so as not to slip easily. The wiper 203 is mounted on the body 201. The wiper 203 is composed of a first roller 203a and a second roller 203b that roll in the X direction (or −X direction) on the cleaning target surface F due to the movement of the body 201.

Auxiliary rollers 204 are provided before and after the wiper 203. The wipers 203 (203a and 203b) and the auxiliary roller 204 are fixed to the movable plate 207 via the legs 205 and 206 extending in the Y direction, respectively. The movable plate 207, the legs 205 and 206, the auxiliary roller 204, and the wiper 203 form a group like a wiper carriage. The movable plate 207 is attached to the fixed plate 209 via a spring 208. The fixing plate 209 is fixed to the body 201.

The body 201 is equipped with the first sensor 211 and the second sensor 212. The first sensor 211 is provided in front of the body 201 in the moving direction, and faces the cleaning target surface F with a slight predetermined gap. The second sensor 212 is provided behind the body 201 in the moving direction, and faces the surface F to be cleaned with a slight predetermined gap. Both the first sensor 211 and the second sensor 212 are, for example, an optical sensor integrated with light emitting and receiving. The first sensor 211 and the second sensor 212 are arranged so as to be hidden under the body 201 in order to make them less susceptible to the influence of excess scattered light in the surroundings. The shorter the predetermined gap as possible is suitable for accurate measurement, for example, 1 mm or less is preferable.

A camera 213 as an imaging device is mounted at the tip of the body 201 in the moving direction. The camera 213 faces the surface F to be cleaned.

FIG. 5 is a diagram showing an outline of a control configuration of the cleaning device 200. The cleaning device 200 includes a control unit 215. The control unit 215 includes, for example, a computer, and the computer executes software (computer program) to realize necessary control functions. The software is stored in the storage unit 217. The control unit 215 is connected to the above-mentioned first sensor 211, second sensor 212, and camera 213, and receives detection outputs from each. Further, the control unit 215 drives the drive unit 202 to move the body 201.

The power supply unit 216 supplies the control unit 215 with a power source for driving the drive unit 202 and a power source for control. The power supply unit 216 is typically a storage battery, but a solar cell can also be used alone or in combination. In this example, the wiper 203 is not electrically controlled, but an electric actuator can be used to adjust the force of pressing the wiper 203 against the surface F to be cleaned.

The storage unit 217 can store information on the shape and size of the cleaning target surface F in order to recognize the positional relationship with the cleaning target surface F. The control unit 215 is connected to the communication unit 218, and can transmit information to the external monitoring control unit 300 via the communication unit 218 and can also receive information from the monitoring control unit 300.

6A and 6B are diagrams for explaining that the optical sensor detects the dirt on the surface F to be cleaned. First, as shown in FIG. 6A, when the cleaning target surface F is not dirty, the light emitted from the light projecting unit T of the first sensor 211 (or the second sensor 212) is reflected by the cleaning target surface F and received. Detected by part R. On the other hand, as shown in FIG. 6B, when sand Sa adheres to the surface F to be cleaned as dirt, the light emitted from the light projecting unit T is scattered and the reflected light reaching the light receiving unit R is reduced. Depending on the degree of dirt, the more dirt there is, the more scattering increases and the less reflected light reaches the light receiving portion R. Therefore, the intensity of the reflected light (detection output of the light receiving portion R) becomes a value depending on the level of dirt on the surface F to be cleaned.

FIG. 7 is a comparative photograph showing the difference in the fiber structure of the wiper 203. The photograph of (b) is the fiber structure of the first roller 203a, and the photograph of (a) is the fiber structure of the second roller 203b. The first roller 203a of (b) is a cloth material in which microfiber fibers are entangled with each other, and is suitable for initial cleaning. The second roller 203b (a) is a cloth material in which the directions of the microfiber fibers are aligned with those of the first roller 203a, and is suitable for finish cleaning. In this way, the two types of rollers roll on the surface F to be cleaned, so that dirt can be effectively adsorbed on the microfibers.

FIG. 8 is a photograph showing a state in which sand is adsorbed on the microfiber, and the photograph of (b) is an enlarged view of the central part of the photograph of (a). Looking at the photograph of (b), it can be seen that the sand is adsorbed on the surface of each microfiber rather than the sand entering between the fibers of the microfiber.

《Cleaning procedure》
FIG. 9 is a diagram showing an example of a state in which the light receiving surface 1f of the array 1 of the photovoltaic power generation device 100 is cleaned by using the cleaning device 200. FIG. 9 shows a state in which the array 1 faces straight up and is horizontal, but the cleaning device 200 may be slightly tilted as long as it does not fall due to gravity. From such a state, cleaning can be performed by moving the cleaning device 200 on the light receiving surface 1f. As a method of movement, for example, the process of starting movement from a predetermined start position, going straight in parallel with one side of the contour of the array 1, turning when it comes to the end, shifting a little to the side, and going straight in the opposite direction. By repeating the above steps, the entire light receiving surface 1f of the array 1 can be cleaned.

Specifically, for example, in the storage unit 217 in FIG. 5, information necessary for accurate movement such as the shape and dimensions of the light receiving surface 1f, a predetermined start position, and a folding position is input and stored in advance. The control unit 215 controls the drive unit 202 based on the stored information, and can move the cleaning device 200 by a predetermined movement path. In addition, the information of the camera 213 can also be used when moving. It should be noted that the control unit 215 may be made to learn a large number of trials in advance so as to make trial and error, and the vehicle may travel based on the learning result.

FIG. 9 also shows an enlarged view of the circled portion of the alternate long and short dash line at the right end of the array 1. In the enlarged view, when the camera 213 is removed from the end of the array 1, the control unit 215 can recognize that the cleaning device 200 has reached the end of the array 1 from the sudden change in the captured image. .. If the end portion is accurately recognized from the image information actually measured by the camera 213, the cleaning device 200 can be more reliably suppressed from falling off.
It is also possible to inspect the module 1M or the array 1 for an abnormality in appearance based on image recognition using the camera 213. On the other hand, when the cleaning device 200 is limited to an application that prevents the cleaning device 200 from falling off from the array 1, a position sensor can be used instead of the camera 213.

It should be noted that a hangar for the cleaning device 200 may be provided in the vicinity of the light receiving surface 1f other than the light receiving surface 1f of the array 1. In this case, the cleaning device 200 may perform cleaning of the light receiving surface 1f with the hangar as the origin, and return to the hangar when the cleaning is completed.

<< Confirmation of cleaning results and re-cleaning >>
FIG. 10 is an example of a flowchart showing processing by the control unit 215 from the start to the end of cleaning by the cleaning device 200. When the cleaning is started, the control unit 215 determines whether or not there is a stop command (step S1). The start command and the stop command are transmitted from, for example, the monitoring control unit 300 (FIG. 5). Since there is no stop command immediately after the start, the control unit 215 moves the cleaning device 200 and executes cleaning by the wiper 203 (step S2). While performing cleaning, the control unit 215 acquires information sent from the first sensor 211, the second sensor 212, and the camera 213 (step S3).

Here, the control unit 215 determines whether or not the detection output of the second sensor 212 is equal to or less than the threshold value in order to confirm the cleanliness of the light receiving surface 1f after the dirt is removed by the wiper 203 (step S4). .. If the detection output of the second sensor 212 is equal to or less than the threshold value, the cleaning result is good, and the control unit 215 determines whether or not the cleaning device 200 has reached the end of the array 1 (step S5). If not, the process returns to step S1 and the same process (steps S1, S2, S3, S4, S5) is repeated.

On the other hand, in step S4, if the detection output of the second sensor 212 is higher than the threshold value (“NO” in step S4), the cleaning result is poor. In this case, the control unit 215 reverses the moving direction so as to pass through the same place as the place just passed, and returns by a predetermined distance (step S6). After that, the control unit 215 executes steps S1 to S4. The movement in step S2 is in the original direction. In step S4, if the detection output of the second sensor 212 is equal to or less than the threshold value, the cleaning result is good. Therefore, the control unit 215 determines whether or not the end of the array 1 has been reached ( Step S5), if not reached, returns to step S1 and repeats the same process (steps S1, S2, S3, S4, S5). In this way, if the dirt is not sufficiently removed by one pass, it can be passed again and "wipe twice". In addition, it can be said to be "wiping three times" including when retreating. Further, if the detection output of the second sensor 212 does not fall below the threshold value even after passing again, the pass may be performed a plurality of times until the detection output falls below the threshold value.

After that, the control unit 215 determines whether or not the cleaning device 200 has reached the end of the array 1 (step S5), and if not, returns to step S1 and performs the same processing (steps S1, S2, S3). Repeat S4 and S5). When it comes to the end of the array 1, the control unit 215 repeats the same process while changing the traveling path (step S8) until the entire surface is cleaned (step S7). When the entire surface is cleaned (“YES” in step S7), the cleaning is completed.

Although omitted in the flowchart of FIG. 10, if a strong wind exceeding a predetermined value is detected before the start of cleaning, the hangar waits without starting the cleaning. If a strong wind above the specified value is detected during cleaning, the cleaning will be stopped immediately, the hangar will be returned, and the system will stand by.

As described above, the cleaning device 200 produces a cleaning result when the level of dirt detected by the second sensor 212 rearward in the moving direction while moving on the light receiving surface 1f is a predetermined level (threshold value) or lower. It is good and the body moves as it is. On the other hand, when the level of dirt detected by the sensor is higher than a predetermined level, control is performed so as to pass through the same place again, and at least "wiping twice" is performed. In this way, the dirt can be wiped a plurality of times, and more reliable cleaning can be performed. Further, since the wiper 203 has a material that adsorbs dirt, it can be wiped dry without using water. Since the wiper 203 adsorbs fine sand with static electricity, it is possible to prevent the light receiving surface 1f from being scratched. Further, since water is not used, a water supply device is not required and the entire device is simplified.

Although not shown in the flowchart of FIG. 10, although the dirt level detected by the first sensor 211 and the dirt level detected by the second sensor 212 are both higher than the first predetermined value, they are higher than the first predetermined value. When the difference between the two levels is smaller than the second predetermined value indicating that the wiper is minute, the control unit 215 determines that it is time to replace the wiper 203. When the wiper 203 becomes dirty, such a state occurs, so that the replacement time can be known without looking directly at the wiper 203.

<< Additional functions of cleaning device >>
FIG. 11 is a diagram showing an outline of the mechanical configuration of the cleaning device 200 as in FIG. 4, but the difference from FIG. 4 is a diagram in the case where the surface F to be cleaned has a protrusion F1 as a step. is there. When the wiper 203 rides on the protrusion F1, the movable plate 207 tilts and the spring 208 contracts as shown in the drawing, and the ground contact property of the first roller 203a and the second roller 203b is maintained. Therefore, even if there is a protrusion F1, the cleaning ability does not decrease.

In this way, by providing the spring 208 that pushes the wiper 203 from the body 201 so that the wiper 203 is in pressure contact with the surface F to be cleaned, the wiper 203 can be stably maintained even if the surface F to be cleaned has some irregularities. It can be pressed against the surface F to be cleaned. In addition, instead of the spring 208, natural rubber, synthetic rubber, sponge or the like can be used as the elastic member.

《Use with flying object》
A large number (for example, several tens) of photovoltaic power generation devices 100 are usually installed on a vast land. It is not economical to prepare one cleaning device 200 for each unit. Therefore, it is more preferable if one cleaning device 200 can clean the light receiving surfaces of a large number of arrays 1. For that purpose, the cleaning device 200 must move between a plurality of arrays. This movement can be done by the hands of the workers, but it is time consuming and inefficient as it roams the vast land. Therefore, consider using it in combination with a hoverable aircraft. The air vehicle is not particularly limited, but a so-called drone is preferable. Current drone technology can carry loads up to 15 kg. The cleaning device 200 can be manufactured with a weight of 15 kg or less.

(1st example)
FIG. 12 is a diagram showing an example of a state in which the light receiving surface 1f of the array 1 of the photovoltaic power generation device 100 is cleaned by using the cleaning device 200 connected to the flying object 400 (drone). In this case, the role of the flying object 400 is to land the cleaning device 200 at the start position on the light receiving surface 1f. After landing, the aircraft 400 has stopped. For the subsequent cleaning, the cleaning device 200 performs this by itself. When the cleaning is completed, the flying object 400 carries the cleaning device 200 to the next array. In this way, one cleaning device 200 can sequentially clean the light receiving surfaces 1f of the plurality of arrays.

Note that the flying object 400 and the cleaning device 200 do not necessarily have to be always connected. During cleaning, the air vehicle 400 is separated from the cleaning device 200, the air vehicle 400 works elsewhere, returns after cleaning, and is connected again to the next array. You may proceed.

(2nd example)
FIG. 13 is a diagram showing another example of a state in which the light receiving surface 1f of the array 1 of the photovoltaic power generation device 100 is cleaned by using the cleaning device 200 connected to the flying object 400. The array 1 is in a horizontal posture, and the light receiving surface 1f faces the ground. This is usually the attitude of Array 1 at night. In this case, the role of the flying object 400 is to support the cleaning device 200 turned upside down in the air in the hovering state, and to press the cleaning device 200 against the light receiving surface 1f with a constant force.

The flying object 400 presses the cleaning device 200 against the start position on the light receiving surface 1f. Maintains the pressing force, but does not move horizontally. For the subsequent cleaning, the cleaning device 200 performs this by itself. When the cleaning is completed, the flying object 400 carries the cleaning device 200 to the next array. In this way, one cleaning device 200 can sequentially clean the light receiving surfaces 1f of the plurality of arrays.

(Supplement)
Although FIGS. 12 and 13 both show an example in which the attitude of the array 1 is horizontal, the cleaning device 200 when used in combination with an air vehicle has a surface to be cleaned vertically or relatively inclined. Cleaning is possible even on steep surfaces.

《Use with vehicle》
FIG. 14 is a diagram showing an example of a state in which the light receiving surface 1f of the array 1 of the photovoltaic power generation device 100 is cleaned by using the cleaning device 200 mounted on the vehicle 500. The array 1 is in a horizontal posture, and the light receiving surface 1f faces the ground. This is usually the attitude of Array 1 at night. The vehicle 500 includes an elevating device 501 that can freely expand and contract in the vertical direction, a table 502 provided on the elevating device 501, and a control unit 503 that controls the elevating device 501. The cleaning device 200 is mounted on the table 502. The cleaning device 200 can freely move horizontally on the table 502.

In this case, first, the vehicle 500 is stopped so that the table 502 comes below the light receiving surface 1f of the array 1. Next, the elevating device 501 is vertically extended, and the cleaning device 200 is pressed against the light receiving surface 1f. The elevating device 501 is provided with a certain degree of elasticity in the vertical direction so that the force of pressing the cleaning device 200 against the light receiving surface 1f is not excessive. For the subsequent cleaning, the cleaning device 200 performs this by itself. When the cleaning by the cleaning device 200 is completed within the range that can be moved on the table 502, the stop position of the vehicle is moved so that the entire light receiving surface 1f can be cleaned. When the cleaning of the entire light receiving surface 1f is completed, the cleaning of the next array 1 is performed for each vehicle 500.

In this way, one cleaning device 200, the vehicle 500, and the like can sequentially clean the light receiving surfaces 1f of the plurality of arrays.
It is also possible to provide the table 502 itself with a horizontal two-dimensional slide function (so-called XY table) and control it by the control unit 503. In that case, the cleaning device 200 does not have to run on its own.

<< About the pressure of the wiper >>
Next, an appropriate pressing force of the wiper 203 with respect to the light receiving surface 1f of the array 1 in "dry wiping" will be examined. FIG. 16 is a graph examining how the output (generated power) of the array changes under the same weather conditions when the conditions of the wiper pressing pressure are changed in the presence of a certain amount of sand. In the figure, first, it is assumed that the output reduction rate when the wiper is not used is 0%. Next, when the wiper was cleaned 360 times (the number of times that 30 years had passed by cleaning once a month) with the wiper pressing pressure set to 735 Pa without spraying sand, the output reduction rate was -2.4%. After spraying sand, the wiper was cleaned 360 times with a pressing pressure of 735 Pa, and the output reduction rate was -4.0%. Further, when sand was sprayed and the wiper was cleaned 360 times with a pressing pressure of 14700 Pa, the output reduction rate reached -19.3%.

From the above results, it is presumed that when the sand is wiped dry, the light receiving surface is finely scratched by the pressing pressure of the wiper. Further, the stronger the pressing pressure, the greater the decrease in output. Assuming that the relationship between the pressing pressure and the output reduction rate is a substantially linear relationship, for example, the pressing pressure P [Pa] at which the absolute value of the output reduction rate is 10% can be obtained from the following relationship.
(P-735): (14700-P) = (10-4): (19.3-10)
In this case, P is 6211 [Pa]. However, in order to allow a little more margin and ensure that the absolute value of the output reduction rate is less than 10%, it is preferable to set P = 5000 [Pa] as the upper limit value. When the pressing pressure P = 5000 [Pa], the absolute value of the output reduction rate is estimated to be about 8.7%.

On the other hand, the minimum pressing pressure required to remove the dirt adhering to the light receiving surface is P = 500 [Pa]. This is because when the pressing pressure is less than 500 [Pa], the effect of removing the adhered dirt is remarkably reduced.
Therefore, the preferred range of pressing pressure P [Pa] is in the range of 500 to 5000.

<< About dirt judgment of array >>
Next, an example of a system for determining the dirt on the light receiving surface of the array 1 will be described. FIG. 17 is a diagram showing a state in which the array 1 is imaged using the flying object 400. In the figure, the flying object 400 has an image pickup device 401. The aircraft body 400 can hover. The image pickup apparatus 401 is a high-resolution camera, and can image the entire light receiving surface of the array 1 with high accuracy.

On the surface of the array 1, the sand becomes muddy and collects due to the rainfall on the sand stains. Such a collection of sand becomes spots that spread by subsequent drying. Such spots are attached everywhere on the surface of the array 1. The spots are light brownish, and it is easy to distinguish the boundary from other parts. Therefore, by analyzing the image captured by the imaging device 401, it is possible to know the ratio of the total area of the spots to the entire area of the surface of the array 1.

FIG. 18 is a diagram showing an example of a dirt determination system mounted on the flying object 400. In addition to the flight control unit 405 that controls its own flight, the aircraft body 400 includes an image pickup device 401, a stain calculation unit 402, a target determination unit 403, and a communication unit 404 for dirt determination. The dirt calculation unit 402 analyzes the image of the array 1 captured by the image pickup apparatus 401, and calculates the ratio of the total area of the spots to the entire surface area of the array 1. It can be estimated that the larger this ratio is, the more dirty the surface of the array 1 is. Therefore, the target determination unit 403 can set a threshold value, for example, and determine that “cleaning is required” if the above ratio exceeds the threshold value and “cleaning is not required” if the ratio does not exceed the threshold value. The target determination unit 403 determines whether or not the imaged array should be the target of cleaning, and the determination result is determined by the communication unit 404 by the communication unit 218 (FIG. 5) or the monitoring control unit 300 (FIG. 5) of the cleaning device 200. ). The aircraft body 400 can sequentially image the array 1 to notify the necessity of cleaning. In this way, the array to be cleaned can be accurately detected in advance.

Note that the functions of the dirt calculation unit 402 and the target determination unit 403 may be configured as artificial intelligence that accurately provides an output of cleaning necessity from the input data of array imaging data.

<< Other >>
In the above embodiment, the cleaning device 200 applied to the concentrating type photovoltaic power generation device 100 has been described, but the same cleaning device 200 is also applied to the solar power generation device of the crystalline silicon module which is not the condensing type. can do. Further, the cleaning device 200 can be applied regardless of whether it is a sun tracking type or a fixed type. Further, the cleaning device 200 can be similarly applied not only to a photovoltaic power generation device but also to a device having a panel-like structure in which dirt such as sand adhering outdoors affects the performance.

<< Supplement >>
It should be noted that the embodiments disclosed this time are examples in all respects and are not restrictive. The scope of the present invention is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 Array 1f Light receiving surface 1M Condensing type photovoltaic power generation module (module)
2 Support mechanism 21 Strut 22 Foundation 23 Drive unit 24 Horizontal axis 25 Tracking stand 25a Reinforcing material 25b Rail 100 Solar power generation device 200 Cleaning device 201 Body 202 Drive unit 203 Wiper 203a 1st roller 203b 2nd roller 204 Auxiliary roller 205, 206 Leg 207 Movable plate 208 Spring 209 Fixed plate 211 1st sensor 212 2nd sensor 213 Camera 215 Control unit 216 Power supply unit 217 Storage unit 218 Communication unit 300 Monitoring control unit 400 Air vehicle 401 Imaging device 402 Dirt calculation unit 403 Target determination unit 404 Communication unit 405 Flight control unit 500 Vehicle 501 Lifting device 502 Table 503 Control unit F Cleaning target surface F1 Protrusion R Light receiving unit Sa Sand T Flooding unit

Claims (14)

1. A cleaning device that cleans the surface to be cleaned.
   A body that can move along the surface to be cleaned and
   A wiper that is mounted on the body in contact with the surface to be cleaned and has a material that adsorbs dirt adhering to the surface to be cleaned.
   A first sensor mounted in front of the body in the moving direction while facing the surface to be cleaned and detecting dirt on the surface to be cleaned.
   A second sensor that is mounted rearward in the moving direction of the body while facing the surface to be cleaned, is on the side opposite to the first sensor when viewed from the wiper, and detects dirt on the surface to be cleaned.
   A control unit that controls the movement of the body along the surface to be cleaned is provided.
   During the movement of the body, the control unit continues the movement when the level of dirt detected by the second sensor is lower than the predetermined level, and when the level is higher than the predetermined level, the control unit passes through the same place again. A cleaning device that controls the moving direction of the body.
2. The cleaning device according to claim 1, wherein the dirt contains sand and the material is microfiber.
3. The cleaning device according to claim 1 or 2, wherein both the first sensor and the second sensor are optical sensors and detect the level of dirt based on the intensity of reflected light.
4. The wiper
   A first roller for initial cleaning that rolls on the surface to be cleaned due to the movement of the body,
   A second roller for finish cleaning, which is behind the first roller in the moving direction and rolls on the cleaning target surface due to the movement of the body.
   The cleaning device according to any one of claims 1 to 3, further comprising.
5. Although the dirt level detected by the first sensor and the dirt level detected by the second sensor are both higher than the first predetermined value, the difference between the two levels indicates that the difference between the two levels is small. The cleaning device according to any one of claims 1 to 4, wherein when the value is smaller than the second predetermined value, the control unit determines that it is time to replace the wiper.
6. The cleaning device according to any one of claims 1 to 5, further comprising an elastic member that pushes the wiper out of the body so that the wiper is in pressure contact with the surface to be cleaned.
7. The cleaning device according to any one of claims 1 to 6, wherein the cleaning target surface is a light receiving surface in an array of photovoltaic power generation devices.
8. The cleaning device according to any one of claims 1 to 7, wherein a camera is mounted on an end portion of the body so as to face the surface to be cleaned.
9. The cleaning device according to any one of claims 1 to 8, wherein a hoverable flying object is attached to the body.
10. The cleaning device according to any one of claims 1 to 9, wherein the pressing pressure for pressing the wiper against the surface to be cleaned is in the range of 500 Pa to 5000 Pa.
11. A photovoltaic power generation device having an array and a cleaning system for a photovoltaic power generation device including a cleaning device for cleaning the light receiving surface of the array.
    The cleaning device
    A body that can move along the light receiving surface and
    A wiper that is mounted on the body in contact with the light receiving surface and has a material that adsorbs dirt adhering to the light receiving surface.
    A first sensor mounted in front of the body in the moving direction while facing the light receiving surface and detecting dirt on the light receiving surface, and
    A second sensor that is mounted rearward in the moving direction of the body while facing the light receiving surface, is on the side opposite to the first sensor when viewed from the wiper, and detects dirt on the light receiving surface.
    A control unit that controls the movement of the body along the light receiving surface is provided.
    During the movement of the body, the control unit continues the movement when the level of dirt detected by the second sensor is lower than the predetermined level, and when the level is higher than the predetermined level, the body passes through the same place again. A cleaning system for photovoltaic power generation equipment that controls the direction of movement.
12. Including a hoverable flying object equipped with an imaging device,
    The cleaning of the photovoltaic power generation device according to claim 11, wherein the flying object determines an array to be cleaned by the cleaning device based on the ratio of the area of dirt to the total area of the light receiving surface of the array imaged. system.
13. It is a cleaning system for photovoltaic power generation equipment that can direct the light receiving surface of the array to the ground.
    A photovoltaic power generator with the light receiving surface of the array horizontal and facing the ground,
    Vehicles parked below the array and
    An elevating device mounted on the vehicle that can expand and contract in the vertical direction,
    It is provided with a cleaning device which can move horizontally on the upper surface of the elevating device and cleans the light receiving surface.
    The cleaning device
    A body that can move along the light receiving surface and
    A wiper that is mounted on the body in contact with the light receiving surface and has a material that adsorbs dirt adhering to the light receiving surface.
    A first sensor mounted in front of the body in the moving direction while facing the light receiving surface and detecting dirt on the light receiving surface, and
    A second sensor that is mounted rearward in the moving direction of the body while facing the light receiving surface, is on the side opposite to the first sensor when viewed from the wiper, and detects dirt on the light receiving surface.
    A control unit that controls the movement of the body along the light receiving surface is provided.
    During the movement of the body, the control unit continues the movement when the level of dirt detected by the second sensor is lower than the predetermined level, and when the level is higher than the predetermined level, the body passes through the same place again. A cleaning system for photovoltaic power generation equipment that controls the direction of movement.
14. A method of cleaning a photovoltaic power generation device, which cleans the light receiving surface of each of a plurality of photovoltaic power generation devices installed apart from each other by using a cleaning device having a wiper made of microfiber.
    With the cleaning device mounted on a hoverable flying object, the cleaning device is approached to an arbitrary solar power generation device to be attached to a predetermined position on the light receiving surface.
    The cleaning device moves along the light receiving surface to clean with a dry wipe, and the cleaning result is checked. If the cleaning result is not good, the cleaning work is executed by passing through the same place a plurality of times.
    When the cleaning is completed, the flying object carries the cleaning device in the air to another uncleaned photovoltaic power generation device.
    A method of cleaning photovoltaic power generation equipment, which repeats the process of cleaning multiple photovoltaic power generation equipment.

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