JP7536664B2 - Inspection methods for wind power generation equipment - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies. Published on the website of Kansai Electric Power Co., Inc. on October 20, 2020 (https://www.kepco.co.jp/corporate/pr/2020/1020_1j.html) Published at the Akita Prefectural Office on November 4, 2020

This disclosure relates to a method for inspecting wind power generation equipment and an unmanned aerial vehicle.

The expansion of offshore wind power generation and the reduction in costs are progressing rapidly worldwide. In particular, in Japan, where suitable locations for onshore wind power generation are limited, the expansion of offshore wind power generation is essential.

The proportion of post-construction operation and maintenance costs in the life cycle costs of offshore wind power generation facilities cannot be ignored. In recent years, with the reduction in costs related to the construction of turbines and structures, the proportion of operation and maintenance costs is approaching the proportion of construction-related costs. Therefore, reducing the time and cost required for regular inspections and special inspections after emergency power generation shutdowns is extremely important for increasing the operating rate of wind power generation facilities and reducing power generation costs.

Conventionally, when inspecting the blades of wind turbines at wind power generation facilities, workers would use a rope hanging from the hub to move along the blades and visually check for damage. This made the inspection process very time-consuming.

Therefore, in order to reduce the burden on workers and cut inspection time and costs, various methods have been proposed for inspecting wind power generation equipment using unmanned aerial vehicles (UAVs) such as drones (see, for example, JP 2019-73999 A (Patent Document 1)).

JP 2019-73999 A

When an offshore wind power generation facility has to make an emergency shutdown due to a lightning strike or other event, it is necessary to carry out a temporary external inspection of the facility before it can resume operation. Previously, it was necessary to travel by ship to the offshore facility to carry out an external inspection, and this journey also took time. Furthermore, depending on the strength of the waves, there were cases in which it was impossible to approach the offshore facility by ship.

In principle, it is possible to use a UAV to shuttle between a base facility on land and an offshore wind power generation facility and inspect the wind turbines using the UAV instead of traveling by ship; however, in practice, this poses many challenges. One challenge is that the specific procedures for inspecting wind power generation facilities using the autonomous flight of a UAV are not clear. If an attempt is made to remotely control an offshore UAV in real time from a base facility on land, rather than using autonomous flight, a time lag in control will occur due to communication delays. For this reason, if the conditions around the UAV have changed when the control command reaches the UAV, the UAV cannot be remotely controlled as intended.

Similar issues can arise when inspecting wind power generation facilities located in remote areas on land, such as mountainous regions. Conventional technology assumes a case in which a UAV is remotely controlled from a nearby location where the wind turbines can be easily seen, and does not solve the above issues.

Therefore, one of the objectives of this disclosure is to provide a method for inspecting wind power generation facilities that are located far away, such as offshore, where visual inspection is difficult, using an autonomous unmanned aerial vehicle, and the configuration of the unmanned aerial vehicle used in this inspection method.

In one aspect of the present disclosure, a method for inspecting a wind power generation facility includes a step of an unmanned aerial vehicle flying autonomously above a wind turbine of the wind power generation facility, a step of a controller provided in the unmanned aerial vehicle determining a current orientation of a nacelle of the wind turbine above the wind turbine, a step of the controller moving the unmanned aerial vehicle to a position directly facing the hub of the wind turbine based on the determined current orientation of the nacelle, a step of the controller determining a current rotation angle of a first blade of the wind turbine at a position directly facing the hub, a step of the controller moving the unmanned aerial vehicle to an inspection start position for the first blade based on the determined current rotation angle of the first blade, a step of the controller taking an inspection image of the first blade with a camera mounted on the unmanned aerial vehicle while moving the unmanned aerial vehicle from the inspection start position along the longitudinal direction of the first blade, and a step of automatically determining a damaged portion of the first blade based on the inspection image of the first blade.

An unmanned aerial vehicle in another aspect of the present disclosure includes a propulsion mechanism for propelling and suspending the unmanned aerial vehicle in the air, a camera, and a controller for controlling the propulsion mechanism and the camera. The controller is configured to autonomously fly the vehicle up to the sky above the wind turbine to be inspected, determine the current orientation of the wind turbine's nacelle above the wind turbine, move the vehicle to a position directly facing the hub of the wind turbine based on the determined current orientation of the nacelle, determine the current rotation angle of a first blade of the wind turbine at the position directly facing the hub of the wind turbine, move the vehicle to an inspection start position for the first blade based on the determined current rotation angle of the first blade, and take an inspection image of the first blade with the camera while moving the vehicle from the inspection start position along the longitudinal direction of the first blade.

According to the above aspect and other aspects, wind power generation facilities that are located far away, such as offshore, where visual inspection is difficult, can be inspected by an autonomous unmanned aerial vehicle.

FIG. 1 is an external view conceptually illustrating an example configuration of a drone. FIG. 2 is a functional block diagram showing the configuration of the drone of FIG. 1 . FIG. 1 is a diagram conceptually illustrating an example of the configuration of a wind turbine in an offshore wind power generation facility. FIG. 2 is a functional block diagram showing a configuration example of a terminal device provided in a base facility. 1 is a flowchart showing an inspection procedure for an offshore wind turbine. FIG. 7 is a diagram for explaining the movement position of the drone in step S130 of FIG. 5. 6 is a diagram for explaining a method of determining the current rotation angle of the blade in step S140 in FIG. 5. 6 is a diagram for explaining a method for determining the inspection start position of the blade in step S150 of FIG. 5. FIG. 6 is a diagram for explaining a path for inspecting the blade in steps S160 to S180 of FIG. 5.

The following describes the embodiments in detail with reference to the drawings. In the following, an example of inspecting offshore wind turbines using a UAV will be described, but the same can be said for inspecting wind turbines installed in remote areas on land, such as mountainous regions. In addition, a drone will be used as an example of a UAV. Note that the same or corresponding parts will be given the same reference symbols, and their descriptions may not be repeated.

[Drone configuration example]
Fig. 1 is an external view conceptually illustrating an example of the configuration of a drone. Fig. 1(A) shows an external view of the drone 10 as seen from the front, and Fig. 1(B) shows an external view of the drone 10 as seen from the right side.

Figure 2 is a functional block diagram showing the configuration of the drone in Figure 1. Figure 2 shows an example of the internal configuration of the main body unit 11 in Figure 1 in more detail.

Referring to Figures 1 and 2, drone 10 comprises a propeller motor 13 and a propeller 14 connected to the upper part of main body 11 via arm 12, and legs 22 attached to the lower part of main body 11. A motor drive circuit 15 for driving propeller motor 13 is provided inside arm 12. Drone 10 further comprises an engine 16 and a generator 17 attached to the lower part of main body 11, cameras 18 and 20 mounted on the lower part of main body 11 via gimbals 19 and 21, respectively, and a LiDAR (Laser Imaging Detection and Ranging) sensor 24 attached to the upper part of main body 11.

In the example of FIG. 1, four sets of propeller motors 13 and propellers 14 are provided, but this is not limited to this. By controlling the rotational speed of each propeller motor 13, it is possible for the drone 10 to ascend and descend vertically, ascend and descend in any diagonal direction, stop in the air, move forward, move backward, move right, move left, rotate right, rotate left, etc. In other words, the propeller motors 13 and propellers 14 form a propulsion mechanism 23 that propels the drone 10 and stops it in the air.

The generator 17 is driven by the engine 16 to generate the electricity required for the operation of the drone 10. This enables the drone 10 to fly for long periods of time and in low temperatures.

The camera 18 is a forward camera 18 for capturing images in front of the drone 10, and the camera 20 is a direct-down camera 20 for capturing images directly below the drone 10. The forward camera 18 includes a high-resolution camera 18A for capturing images for inspection and a low-resolution camera 18B for capturing video images for FPV (First Person View). Similarly, the direct-down camera 20 includes a high-resolution camera 20A for capturing images for inspection and a low-resolution camera 20B for capturing images for FPV. The video images captured by the low-resolution cameras 18B and 20B are transmitted to the terminal device 70 of the base facility. This allows the inspector at the base facility to view the images captured by the cameras 18B and 20B in real time. The shooting directions of the cameras 18 and 20 can be adjusted by actuators constituting the gimbals 19 and 21, respectively. The actuators constituting the gimbals 19 and 21 can also be adjusted by signals from the terminal device 70 of the base facility.

The gimbals 19 and 21 are electric actuators that can adjust the orientation of the cameras 18 and 20 in three dimensions. Based on the detection values of the acceleration sensor and the angular velocity sensor, the gimbals 19 and 21 can keep the imaging directions of the cameras 18 and 20 constant even if the attitude of the drone 10 changes.

The LiDAR sensor 24 detects the distance and angle to an object based on the reflected light from the object by scanning a pulsed laser light. Other distance sensors may be used instead of the LiDAR sensor 24.

As shown in FIG. 2, the main body 11 incorporates a controller 30, a memory device 31, an inertial measurement unit 32, a transceiver 33, a GPS (Global Positioning System) receiver 34, a power supply circuit 35, a storage battery 36, and the like.

The controller 30 controls the operation of the motor drive circuit 15, the camera 18, the LiDAR sensor 24, etc. The controller 30 may be configured by a microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), and a non-volatile memory, or may be configured by a FPGA (Field Programmable Gate Array), or may be configured by a dedicated circuit such as an ASIC (Application Specific Integrated Circuit). The controller 30 may also be configured by a combination of at least two of these.

The storage device 31 includes, as an example, a removable non-volatile recording medium 38 such as an SD memory card, and a reader/writer 37 for writing data to the recording medium 38 and reading data from the recording medium 38. The reader/writer 37 stores still images for inspection taken by the camera 18, the control contents of the controller 30, flight information, and the like, in the recording medium 38 in accordance with commands from the controller 30.

The inertial measurement unit 32 is a sensor unit that integrates an acceleration sensor, an angular velocity sensor (gyro sensor), a geomagnetic sensor, an air pressure sensor, a temperature sensor, and other sensors into a single package. The controller 30 performs autonomous flight and attitude control of the drone 10 based on the detection values of the various sensors in the inertial measurement unit 32.

The transceiver 33 transmits and receives information such as signals and data to and from the transceiver installed in the wind turbine being inspected and the transceiver of the terminal device at the land-based base facility. For example, the transceiver 33 receives information on the operating status of the wind turbine and commands from the terminal device at the base facility. The transceiver 33 also transmits monitoring video images taken by the low-resolution cameras 18B and 20B to the base facility in accordance with commands from the controller 30.

The GPS receiver 34 receives signals from GPS satellites. The controller 30 detects the current position of the drone 10 based on the signals received by the GPS receiver 34.

The power supply circuit 35 generates a power supply voltage to drive each part of the drone 10 based on the power generated by the generator 17.

The storage battery 36 is used as an auxiliary power source for the drone 10. For example, the storage battery 36 supplies power to drive the controller 30, the storage device 31, the transceiver 33, etc. while the engine 16 and the generator 17 are stopped.

[Windmill configuration example]
Fig. 3 is a conceptual diagram showing an example of the configuration of a wind turbine in an offshore wind power generation facility. Referring to Fig. 3, the wind turbine 40 includes a nacelle 43 mounted on the top of a tower 44, a hub 42, and three blades 41 attached to the hub 42. The bottom of the tower 44 is connected to a floating body 46 via a base 45. This allows the tower 44 to float above the sea surface 49.

The blades 41 rotate around the axial direction of the rotor shaft 50 by the rotation of the rotor shaft 50 connected to the hub 42. In addition, the angle (pitch angle 63) of the blades 41 around the longitudinal axis and the angle (yaw angle) of the nacelle 43, which can rotate around the longitudinal axis of the tower 44, can be adjusted.

The nacelle 43 houses a gearbox 52, a brake device 53, a generator 54, a controller 60, and a transceiver 61.

The speed increaser 52 is provided between the rotor shaft 50 and the power transmission shaft 51, and increases the rotation speed of the rotor shaft 50, causing the power transmission shaft 51 to rotate at the increased rotation speed. The brake device 53 stops the rotation of the power transmission shaft 51 according to a command from the controller 60. The generator 54 generates AC power by the rotation of the power transmission shaft 51. The AC power generated by the generator 54 is transmitted to the transformer 56 via the power cable 55, and is boosted by the transformer 56. Furthermore, the AC power boosted by the transformer 56 is transmitted to the onshore power facility via the power cable 57.

The controller 60 controls the overall operation of the wind turbine 40. For example, it adjusts the pitch angle of the blades 41 and the yaw angle of the nacelle 43 based on the measurement results of a wind direction and anemometer (not shown) installed on the top of the nacelle 43. The hardware configuration of the controller 60 can be various, similar to the case of the controller 30 of the drone 10 shown in FIG. 2.

The controller 60 further exchanges information between the drone 10 and a base facility on land via a transceiver 61 and an antenna 62. The transceiver 61 may be configured to relay communication between the drone 10 and the base facility. Wired communication such as optical fiber communication may be used for communication between the wind turbine 40 and the base facility on land.

[Example of the configuration of a terminal device at a base facility]
4 is a functional block diagram showing an example of the configuration of a terminal device provided in a base facility. The terminal device 70 is used for monitoring the drone 10 while it is moving and during inspection of the wind turbine 40, and for analyzing images for inspection.

As shown in FIG. 4, the terminal device 70 is based on a computer including a CPU 71, a RAM 72, and a non-volatile memory 73. The terminal device 70 further includes a display device 74, an input device 75, a storage device 76, and a transceiver 78. These components are connected to each other via a bus 79.

A liquid crystal display or an organic electroluminescence (EL) display can be used as the display device 74. For example, the display device 74 displays video images captured by the cameras 18B and 20B during inspection of the wind turbine 40 and during movement between the onshore base facility and the offshore wind turbine 40.

The input device 75 includes a keyboard and mouse for accepting input from the inspector to the terminal device 70.

The storage device 76 is configured to include a reader/writer for reading data from a removable recording medium. For example, the reader/writer of the storage device 76 can be equipped with a recording medium 38 that stores inspection images captured by the camera 18 of the drone 10.

The transceiver 78 communicates with the transceiver 33 of the drone 10 and the transceiver 61 of the wind turbine 40 via the antenna 77.

[Inspection procedures for offshore wind turbines]
Below, based on the configurations of the drone 10, wind turbine 40, and terminal device 70 described above, the inspection procedure for the wind turbine 40 of an offshore wind power generation facility will be described.

Figure 5 is a flow chart showing the inspection procedure for an offshore wind turbine. First, in step S100 of Figure 5, the terminal device 70 installed at the onshore base facility receives a notification of an emergency shutdown of the generator 54 from the offshore wind turbine 40 via the transceiver 78.

At the time of emergency stop, the controller 60 of the wind turbine 40 adjusts the yaw angle of the nacelle 43 so that the rotating surface of the blade 41 receives the wind head-on, and adjusts the pitch angle 63 of the blade 41 so that the wind direction is parallel to the wind-receiving surface of the blade 41. This prevents the blade 41 from receiving lift from the wind, preventing damage to the wind turbine 40.

Furthermore, when the wind speed is relatively low, the controller 60 of the wind turbine 40 uses the brake device 53 to completely stop the rotation of the blades 41. This makes it easier to inspect the blades 41. When the wind speed is relatively high, the controller 60 puts the blades 41 in a rotatable state in order to prevent damage to the wind turbine 40. In this case, too, the pitch angle 63 of the blades 41 is adjusted so that they receive almost no lift from the wind, so the blades 41 rotate gently.

In the next step S110, the inspector starts the engine 16 and generator 17 of the drone 10, and further causes the controller 30 of the drone 10 to start an emergency inspection of the wind turbine 40, for example by executing a program. This causes the drone 10 to start flying above the wind turbine 40 to be inspected.

More specifically, the controller 30 of the drone 10 determines the flight direction of the drone based on its own position information based on the GPS signal received by the GPS receiver 34 and on the position information of the wind turbine 40 to be inspected received from the terminal device 70. The controller 30 controls the motor drive circuit 15 to cause the drone to take off to a sufficient height and then move the drone in the determined flight direction. The controller 30 continues to move the drone based on its own position information from the GPS signal until it reaches the sky above the wind turbine 40 to be inspected.

In the next step S120, the controller 30 of the drone 10 controls the motor drive circuit 15 to stop the drone in mid-air above the nacelle 43 of the wind turbine 40 to be inspected. In this stopped state, the controller 30 determines the current stopping direction of the nacelle 43.

More specifically, the controller 30 uses the direct-down camera 20 to photograph the nacelle 43 from a position above the wind turbine 40. Based on the photographed image of the nacelle 43, the controller 30 detects the angle of deviation between the direction of the stopped nacelle 43 and the stopping direction of the aircraft (for example, the forward direction). Next, the controller 30 detects the direction of the geomagnetic field using the geomagnetic sensor of the inertial measurement unit 32. Based on the detection result of the geomagnetic field, the controller 30 determines the direction of the stopping direction of the aircraft, and further determines the current stopping direction of the nacelle 43 (i.e., the direction in front of the hub 42) from this determination result.

In the next step S130, the controller 30 of the drone 10 moves the drone 10 to a position directly in front of the hub 42 based on the determined information on the current orientation of the nacelle 43, and positions the drone 10 so that the front of the drone faces the hub 42.

Figure 6 is a diagram to explain the movement position of the drone in step S130 of Figure 5.

As shown in FIG. 6, a virtual circumference line 87 can be imagined at the same height as the rotation axis of the blade 41 and at a certain distance from the axis of the rotation axis 86 of the nacelle 43. The radius of the virtual circumference line 87 is set so that the drone 10 does not collide with the blade 41 and almost the entire blade 41 is within the shooting range of the forward camera 18. On this virtual circumference line 87, the direction directly facing the hub 42, which is determined based on the current stopping orientation of the nacelle 43, is the target position 85 to which the drone 10 should be moved. The controller 30 of the drone 10 moves the drone 10 so that its position based on the GPS signal matches the target position 85. Then, when the drone reaches the target position 85, the controller 30 rotates the drone so that the front of the drone faces the hub 42 based on the direction of the geomagnetic field detected by the geomagnetic sensor.

Returning to FIG. 5, in the next step S140, the controller 30 of the drone 10 uses the forward camera 18 to capture an image of the hub 42 and the blades 41 (41A, 41B, and 41C in FIG. 7) from a position directly facing the hub 42. The controller 30 determines the current rotation angle of the blade 41 based on the captured image of the blade 41. If the rotation of the blade 41 is stopped, the current rotation angle of the blade 41 is the stop angle. If the blade 41 is rotating slowly, the controller 30 determines the current rotation angle of the blade 41 based on multiple images of the blade 41.

Figure 7 is a diagram for explaining a method for determining the current rotation angle of the blade in step S140 of Figure 5. With reference to Figure 7, the controller 30 first determines the vertical direction (0°) in the captured image. The vertical direction can be determined from the direction of the tower 44 relative to the hub 42. Next, the controller 30 determines the angle α from the determined vertical direction to the first blade 41A (i.e., the current rotation angle of the first blade 41A). The current rotation angle α of the first blade 41A is a maximum of 120°.

Referring again to FIG. 5, in the next step S150, the controller 30 of the drone 10 determines the blade inspection start position based on the current rotation angle of the first blade 41A.

Figure 8 is a diagram for explaining a method for determining the inspection start position of the blades in step S150 of Figure 5. Figure 8 (A) shows a view of the blades 41 and the nacelle 43 from above, and Figure 8 (B) shows a view of the blades 41 (41A, 41B, 41C) and the hub 42 from the front.

8(A) and 8(B), a virtual circumferential line 89 can be assumed to be equidistant from the axis of the rotation shaft 88 of the blade 41 within a plane at a certain distance from the rotation plane of the blade 41. The distance from the rotation plane of the blade 41 to the virtual circumferential line 89 is set to a position where the drone 10 can photograph the detailed state of the surface of the blade 41 without colliding with the blade 41. The radius of the virtual circumferential line 89 is set so that the end point of the blade 41 close to the hub 42 is within the shooting range of the forward camera 18A or the direct below camera 20A. The inspection start position is point A in FIG. 8, which is located on the virtual circumferential line 89 in the direction of the current rotation angle (stop angle) of the blade 41 from the center of the virtual circumferential line 89. When the blade 41 is rotating slowly, point A, which is the inspection start position, is set at a position downstream of the rotation from the direction of the current rotation angle. Point A corresponds to a point moved a certain distance and a certain angle β from position 85 where the hub 42 and blade 41 were photographed in step S140. In this embodiment, as shown in FIG. 9, the initial photographing start position is point A1, which is moved from point A in the short direction of blade 41A in order to photograph the first wind receiving surface 92 of blade 41A.

Referring again to FIG. 5, in the next step S160, the controller 30 of the drone 10 controls the motor drive circuit 15 to move the drone 10 to the inspection start position determined in step S150. The controller 30 then adjusts the position and orientation of the drone 10 so that the blade 41A to be inspected is captured in the center of the image by the forward camera 18A or the directly below camera 20A.

In the next step S170, the controller 30 of the drone 10 controls the motor drive circuit 15 to move the drone 10 from the inspection start position of the blade 41A to be inspected along the longitudinal direction of the blade 41A, while capturing inspection images with the camera 18A or 20A. If the blade 41 is in a rotatable state and is actually rotating slowly, the controller 30 uses the LiDAR sensor 24 to keep the distance between the drone 10 and the blade 41A to be inspected constant in accordance with the rotation of the blade 41, while moving the drone 10 along the longitudinal direction of the blade 41A, and captures inspection images with the camera 18. This allows inspection images to be continuously captured in accordance with the rotation of the blade 41.

In the next step S180, the controller 30 of the drone 10 changes the surface of the blade 41A to be photographed and repeats steps S160 and S170. In this embodiment, in the cross-sectional view of the blade 41A shown in FIG. 9(B), images are taken of the first wind receiving surface 92 of the blade 41A, the second wind receiving surface 93 opposite the first wind receiving surface 92, and the leading edge 90 of the blade 41A. In addition, an image may be taken near the trailing edge 91 of the blade 41A.

If there is another blade to be inspected (YES in step S190), the controller 30 of the drone 10 repeats steps S160 to S180 for that blade.

Figure 9 is a diagram for explaining the path for inspecting the blades in steps S160 to S180 of Figure 5. Figure 9(A) shows a front view of the blades 41 (41A, 41B, 41C), hub 42, and tower 44, and Figure 9(B) shows a cross-sectional view of blade 41A.

Referring to FIG. 9, first, the first wind surface 92 of the first blade 41A is photographed. To this end, the controller 30 of the drone 10 moves the drone from point A described with reference to FIG. 8 to point A1 located in the short direction of the blade 41A (path a1). After that, the controller 30 photographs the blade 41A with the camera 18A or 20A while moving the drone from point A1 to point A2 (path a2) along the long direction of the blade 41A.

Next, to photograph the second wind surface 93 of the blade 41, the controller 30 moves the aircraft from point A2 to point A3 located in the short direction of the blade 41A (path a3). After that, the controller 30 photographs the blade 41A with the camera 18A or 20A while moving the aircraft from point A3 to point A4 (path a4) along the longitudinal direction of the blade 41A.

Next, in order to photograph the leading edge 90 of the blade 41A, the controller 30 moves the aircraft from point A4 to point A located in the short direction of the blade 41A (path a5). Note that if the blade 41 is in a rotatable state, point A may not coincide with the original point A. The controller 30 then photographs the blade 41A with the camera 18A or 20A while moving the aircraft from point A to point A5 (path a6) along the longitudinal direction of the blade 41A. After photographing is completed, the controller 30 moves the aircraft from point A5 to point A (path a7).

Next, to photograph the second blade 41B, the controller 30 moves the aircraft to point B, which is 120° away from point A in the rotation direction of the blade 41. The controller 30 photographs the second blade 41B with the camera 18A or 20A along the same path as in the case of the first blade 41A.

Next, to photograph the third blade 41C, the controller 30 moves the aircraft to point C, which is 120° away from point B in the rotational direction of the blade 41. The controller 30 photographs the third blade 41C with the camera 18A or 20A along the same path as in the case of the first blade 41A.

Referring again to FIG. 5, after completing the photographing of all blades 41 of the wind turbine 40 to be inspected (NO in step S190), the controller 30 of the drone 10 moves the drone from the wind turbine 40 to a base facility on land based on the GPS signal and lands it (step S200). The inspector imports the captured inspection images from the recording medium 38 into the storage device 76 of the terminal device 70. Note that the importing of the inspection images may be performed automatically by the terminal device 70 using a communication line between the drone 10 and the terminal device 70.

In the next step 210, the CPU 71 of the terminal device 70 operates according to a program to automatically determine the location of damage to the blades 41 of the wind turbine 40 being inspected based on the captured inspection image. Machine learning techniques can be used to automatically determine the location of damage to the blades 41. This completes the inspection of the wind turbine 40 that has been brought to an emergency stop.

In steps S120 and S140 above, information from the LiDAR sensor 24 may be used instead of image information from the cameras 18 and 20.

[effect]
By following the inspection procedure described above, it becomes possible to use the autonomously flying drone 10 to inspect wind power generation equipment that is far away, such as offshore, where it is difficult to see with the naked eye.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The scope of this application is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

10 drone (unmanned aerial vehicle), 11 main body, 13 propeller motor, 14 propeller, 15 motor drive circuit, 16 engine, 17, 54 generator, 18 forward camera, 20 downward camera, 19, 21 gimbal, 24 LiDAR sensor, 23 propulsion mechanism, 30, 60 controller, 32 inertial measurement unit, 33, 61, 78 transceiver, 34 GPS receiver, 40 wind turbine, 41 blade, 41A first blade, 42 hub, 43 nacelle, 44 tower, 70 terminal device, 85 position directly facing the hub, 86 nacelle rotation axis, 88 blade rotation axis, 87, 89 virtual circumference, 90 leading edge, 91 trailing edge, 92, 93 wind receiving surface.

Claims (5)

A method for inspecting a wind power generation facility, comprising:
A controller mounted on the unmanned aerial vehicle autonomously flies the unmanned aerial vehicle to above the wind turbine based on a position of the unmanned aerial vehicle based on a satellite positioning signal and position information of the wind turbine of the wind power generation facility;
The controller determines a current orientation of a nacelle of the wind turbine above the wind turbine based on information from a geomagnetic sensor mounted on the unmanned aerial vehicle and an image captured by a camera mounted on the unmanned aerial vehicle from above the wind turbine;
a step of the controller moving the wind turbine to a position directly facing a hub of the wind turbine based on the determined current orientation of the nacelle;
The controller determines a current rotation angle of a first blade of the wind turbine based on an image captured by the camera from a position directly facing the hub , and, when the blade of the wind turbine is rotating, determines a current rotation angle of the first blade based on a plurality of captured images ;
the controller moves the controller to an inspection start position for the first blade based on the determined current rotation angle of the first blade, and when the blades of the wind turbine are rotating, sets the inspection start position to a position downstream of the direction of the current rotation angle of the first blade ;
the controller takes an inspection image of the first surface of the first blade with the camera while moving the unmanned aerial vehicle along the longitudinal direction of the first blade from the inspection start position , and, when the wind turbine blades are rotating, takes the inspection image while moving the unmanned aerial vehicle along the longitudinal direction of the first blade while keeping a constant distance between the unmanned aerial vehicle and the first blade in accordance with the rotation of the first blade based on information from a distance sensor mounted on the unmanned aerial vehicle;
taking inspection images of other surfaces of the first blade and other blades;
and automatically determining locations of damage to each of the wind turbine blades based on the inspection images of each of the wind turbine blades. 2. The method for inspecting a wind power generation facility according to claim 1 , wherein the position directly facing the hub is on a first imaginary circumferential line that is at the same height as a rotation shaft of the blades of the wind turbine and equidistant from an axis of the rotation shaft of the nacelle. 3. The method for inspecting wind power generation equipment according to claim 1 , wherein the inspection start position is on a second imaginary circumferential line that is a fixed distance from the rotation plane of the blades of the wind turbine toward the hub and is equidistant from an axis of the rotation shaft of the blades. The method for inspecting wind power generation equipment according to any one of claims 1 to 3 , wherein the wind turbine is installed offshore. An unmanned aerial vehicle,
a propulsion mechanism for propelling and hovering the unmanned aerial vehicle;
A camera and
A satellite positioning signal receiver;
A geomagnetic sensor;
A distance sensor;
a controller for controlling the propulsion mechanism and the camera;
The controller:
Based on the position of the aircraft based on the satellite positioning signal and position information of the wind turbine to be inspected, the aircraft autonomously flies to above the wind turbine;
determining a current orientation of a nacelle of the wind turbine above the wind turbine based on information from the geomagnetic sensor and an image captured by the camera above the wind turbine;
moving the aircraft to a position directly facing a hub of the wind turbine based on the determined current orientation of the nacelle;
determining a current rotation angle of a first blade of the wind turbine based on an image captured by the camera from a position directly facing a hub of the wind turbine , and, when the blade of the wind turbine is rotating, determining a current rotation angle of the first blade based on a plurality of captured images;
Based on the determined current rotation angle of the first blade, the wind turbine moves to an inspection start position of the first blade , and when the blades of the wind turbine are rotating, the inspection start position is set to a position downstream of the direction of the rotation of the first blade relative to the direction of the current rotation angle;
While moving the vehicle from the inspection start position along the longitudinal direction of the first blade, an inspection image of a first surface of the first blade is taken with the camera , and when the blades of the wind turbine are rotating, the vehicle is moved along the longitudinal direction of the first blade while maintaining a constant distance between the vehicle and the first blade in accordance with the rotation of the first blade based on information from the distance sensor, and the inspection image is taken;
The unmanned aerial vehicle is configured to take further inspection images of other surfaces of the first blade and other blades .

Images