JP7789644B2 - Wind power generation facility inspection method and unmanned aerial vehicle - Google Patents

Description

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 cost reductions are progressing rapidly worldwide. In particular, expanding the adoption of offshore wind power generation is essential in Japan, where there are limited locations suitable for the introduction of onshore wind power generation.

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, as costs related to the construction of turbines and structures have decreased, 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 availability rate of wind power generation facilities and reducing power generation costs.

Previously, 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.

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 turbine at an offshore wind power generation facility is struck by lightning or other force and the facility is forced to shut down, an emergency external inspection of the facility is required before operation can be resumed. Previously, an external inspection required a vessel to travel to the facility, which also took time. Furthermore, depending on the strength of the waves, it was sometimes impossible to approach the facility by vessel.

In principle, it is possible to inspect wind turbines using UAVs by flying them back and forth between a base facility on land and an offshore wind power generation facility, instead of using ships for transportation. However, in practice, this poses many challenges. One challenge is that the specific procedures for inspecting wind power generation facilities using autonomous UAV flight are not clear. Instead of autonomous flight, if an attempt is made to remotely control an offshore UAV in real time from a base facility on land, communication delays will result in a time lag in control. As a result, if the conditions around the UAV have changed by the time 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 that UAVs are 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 located at such a great distance that they are difficult to see, such as offshore, using an autonomously flying unmanned aerial vehicle, and the configuration of the unmanned aerial vehicle used in this inspection method.

A method for inspecting wind power generation facilities in one aspect of the present disclosure includes the steps of: a controller provided on an unmanned aerial vehicle acquiring the direction of the rotational axis of the wind turbine blades at a first time point; the controller causing a camera mounted on the unmanned aerial vehicle to photograph the wind turbine blades while moving the unmanned aerial vehicle along the circumference of at least one front circle, the circle having a central axis oriented in the same direction as the rotational axis of the wind turbine blades at the first time point and on the same side of the wind turbine tower as the blades; and the controller causing the camera mounted on the unmanned aerial vehicle to photograph the wind turbine blades while moving the unmanned aerial vehicle along the circumference of at least one back circle, the circle having a central axis oriented in the same direction as the rotational axis of the wind turbine blades at the first time point and on the opposite side of the wind turbine tower from the blades.

A method for inspecting wind power generation facilities in one aspect of the present disclosure includes the steps of: a controller provided on an unmanned aerial vehicle acquiring the direction of the rotational axis of the wind turbine blades at a first time point; the controller moving the unmanned aerial vehicle along the periphery of a first circle, the first circle having a central axis in the same direction as the rotational axis at the first time point and on the same side of the wind turbine tower as the blades; and causing a camera mounted on the unmanned aerial vehicle to capture inspection images of the wind turbine blades while the unmanned aerial vehicle is moving; a controller provided on the unmanned aerial vehicle acquiring the direction of the rotational axis of the wind turbine blades at a second time point; the controller moving the unmanned aerial vehicle along the periphery of a second circle having a central axis in the same direction as the rotational axis at the second time point and on the same side of the wind turbine tower as the blades; and causing the camera mounted on the unmanned aerial vehicle to capture inspection images of the wind turbine blades while the unmanned aerial vehicle is moving. the controller in the unmanned aerial vehicle acquiring the direction of the rotation axis of the wind turbine blades at a third time point; the controller moving the unmanned aerial vehicle along the periphery of a third circle having a central axis in the same direction as the rotation axis at the third time point and located on the opposite side of the blades relative to the wind turbine tower, and causing the camera mounted on the unmanned aerial vehicle to take inspection images of the wind turbine blades while the unmanned aerial vehicle is moving; the controller in the unmanned aerial vehicle acquiring the direction of the rotation axis of the wind turbine blades at a fourth time point; the controller moving the unmanned aerial vehicle along the periphery of a fourth circle having a central axis in the same direction as the rotation axis at the fourth time point and located on the opposite side of the blades relative to the wind turbine tower, and causing the camera mounted on the unmanned aerial vehicle to take inspection images of the wind turbine blades while the unmanned aerial vehicle is moving.

An unmanned aerial vehicle in another aspect of the present disclosure includes a propulsion mechanism for propelling and hovering the unmanned aerial vehicle, a camera, and a controller for controlling the propulsion mechanism and the camera. The controller acquires the direction of the rotational axis of the wind turbine blades, moves the unmanned aerial vehicle along the periphery of at least one front circle having a central axis in the same direction as the rotational axis of the wind turbine blades and located on the same side of the wind turbine tower as the blades, moves the unmanned aerial vehicle along the periphery of at least one rear circle having a central axis in the same direction as the rotational axis of the wind turbine blades and located on the opposite side of the wind turbine tower as the blades, and causes the camera mounted on the unmanned aerial vehicle to take inspection images of the wind turbine blades while the unmanned aerial vehicle is moving.

According to one or more of the above aspects, wind power generation facilities located far away, such as offshore, where visual inspection is difficult, can be inspected using autonomous unmanned aerial vehicles.

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 an example of the configuration of a terminal device installed in a base facility. FIG. 2 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed obliquely relative to the wind turbine 40. FIG. 2 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from the front of the wind turbine 40. FIG. 1 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from the rear side of the wind turbine 40. FIG. 2 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from the side of the wind turbine 40. FIG. 2 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from above the wind turbine 40. 4 is a flowchart showing an inspection procedure for the wind turbine 40 according to the first embodiment. FIG. 11 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed obliquely from the wind turbine 40. FIG. 11 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from the front of the wind turbine 40. FIG. 11 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from the rear side of the wind turbine 40. FIG. 11 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from the side of the wind turbine 40. FIG. 11 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from above the wind turbine 40. 10 is a flowchart showing an inspection procedure for the wind turbine 40 according to the second embodiment. FIG. 11 is a diagram showing the flight path of the drone 10 in the third embodiment, viewed obliquely from the wind turbine 40. FIG. 11 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from the front of the wind turbine 40. FIG. 11 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from the rear side of the wind turbine 40. FIG. 11 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from the side of the wind turbine 40. FIG. 11 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from above the wind turbine 40. 10 is a flowchart showing an inspection procedure for the wind turbine 40 according to the fourth embodiment. 13 is a flowchart showing an inspection procedure for the wind turbine 40 according to the fifth embodiment.

Embodiments will be described in detail below with reference to the drawings. Below, an example of using a UAV to inspect offshore wind turbines will be described, but the same applies to inspecting wind turbines located in remote areas on land, such as mountainous regions. Furthermore, a drone will be used as an example of a UAV. Note that the same or corresponding parts will be designated by the same reference symbols, and their description may not be repeated.

[First embodiment]
(Drone configuration example)
1A and 1B are external views conceptually illustrating an example of the configuration of a drone 10. Fig. 1A shows an external view of the drone 10 as seen from the front, and Fig. 1B 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 11 in Figure 1 in more detail.

Referring to Figures 1 and 2, the drone 10 comprises a propeller motor 13 and a propeller 14 connected to the upper part of the main body 11 via an arm 12, and legs 22 attached to the lower part of the main body 11. A motor drive circuit 15 for driving the propeller motor 13 is provided inside the arm 12. The drone 10 also comprises an engine 16 and a generator 17 attached to the lower part of the main body 11, cameras 18 and 20 mounted on the lower part of the 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 the main body 11.

In the example shown in Figure 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, the drone 10 can ascend and descend vertically, ascend and descend in any diagonal direction, stop in mid-air, move forward, backward, move right, move left, rotate right, rotate left, and so on. In other words, the propeller motors 13 and propellers 14 form a propulsion mechanism 23 that propels the drone 10 forward and stops it in mid-air.

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

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

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

The LiDAR sensor 24 detects the distance and angle to an object based on the light reflected from the object by scanning with 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 storage 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, camera 18, LiDAR sensor 24, etc. The controller 30 may be configured as a microcomputer including a CPU (Central Processing Unit), RAM (Random Access Memory), and non-volatile memory, or as a field programmable gate array (FPGA), or as a dedicated circuit such as an application specific integrated circuit (ASIC). The controller 30 may also be configured as a combination of at least two of these.

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

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

Transceiver 33 transmits and receives signals, data, and other information to and from transceivers installed on the wind turbine being inspected and to transceivers on the terminal device at the onshore base facility. For example, transceiver 33 receives information about the operating status of the wind turbine and commands from the terminal device at the base facility. Transceiver 33 also transmits monitoring video images captured by low-resolution cameras 18B and 20B to the base facility in accordance with commands from 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, memory device 31, transceiver 33, etc. when the engine 16 and generator 17 are stopped.

(Example of wind turbine configuration)
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 41A, 41B, and 41C 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.

Blades 41A, 41B, and 41C rotate about the axial direction of rotor shaft 50 as rotor shaft 50, which is connected to hub 42, rotates. Furthermore, the angle (pitch angle 63) of blade 41 about its longitudinal axis and the angle (yaw angle) of nacelle 43, which can rotate about the longitudinal axis of tower 44, can be adjusted. Rotor shaft 50 is the rotation axis KD of blades 41A, 41B, and 41C. Rotation axis KD of blades 41A, 41B, and 41C is perpendicular to the plane of rotation of blades 41A, 41B, and 41C.

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 located between the rotor shaft 50 and the power transmission shaft 51 and increases the rotational speed of the rotor shaft 50, causing the power transmission shaft 51 to rotate at the increased rotational speed. The brake device 53 stops the rotation of the power transmission shaft 51 in accordance with commands 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. The AC power boosted by the transformer 56 is then transmitted to onshore power equipment 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 wind direction and speed meters (not shown) installed on 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 Figure 2.

The controller 60 also exchanges information between the drone 10 and the on-shore base facility via the transceiver 61 and antenna 62. The transceiver 61 may be configured to relay communications between the drone 10 and the base facility. Wired communications, such as optical fiber communications, may also be used for communications between the wind turbine 40 and the on-shore base facility.

(Configuration example of terminal device at base facility)
4 is a functional block diagram showing an example of the configuration of a terminal device installed 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 inspection images.

As shown in FIG. 4, the terminal device 70 is based on a computer including a CPU 71, RAM 72, and 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 interconnected 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 moving 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 fitted 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.

(Drone flight path)
Fig. 5 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from an oblique direction relative to the wind turbine 40. Fig. 6 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from the front of the wind turbine 40. Fig. 7 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from the back of the wind turbine 40. Fig. 8 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from the side of the wind turbine 40. Fig. 9 is a diagram showing the flight path of the drone 10 in the first embodiment as viewed from above the wind turbine 40.

Figures 5 to 9 show circles CA and CB as the flight path of drone 10.

Circle CA has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is a front circle on the same side of the tower 44 of wind turbine 40 as the blades. The radius of circle CA is ra. The distance between the plane of circle CA and the plane of rotation of blades 41A, 41B, and 41C is d1.

Circle CB has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is the rear circle on the opposite side of the blades with respect to tower 44 of wind turbine 40. The radius of circle CB is rb. The distance between the plane of circle CB and the plane of rotation of blades 41A, 41B, and 41C is d2.

Here, ra = rb and d1 = d2 may also be used.

The vertical positions of the central axis SA of the circle CA and the central axis SB of the circle CB may be the same as or different from the vertical position of the rotation axis KD.

The flight path of this embodiment is more desirable when the direction of the rotation axis KD of blades 41A, 41B, and 41C does not change over time, or if it does change over time, the amount of change is small. In this case, the drone 10 flies along circles CA and CB at a time after first time point t1, but the relative positional relationship of circles CA and CB to the wind turbine 40 remains the same as at the first time point or does not change significantly.

(Inspection procedures for offshore wind turbines)
Below, based on the configuration 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 10 is a flowchart showing the inspection procedure for the wind turbine 40 in the first embodiment.

In step S101, 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.

In step S102, the inspector starts the engine 16 and generator 17 of the drone 10, and then causes the controller 30 of the drone 10 to begin an emergency inspection of the wind turbine 40, for example by running a program. This causes the drone 10 to begin flying toward 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, which is based on the GPS signals received by the GPS receiver 34, and on the position information of the wind turbine 40 to be inspected, which is 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 moves the drone in the determined flight direction. The controller 30 continues to move the drone based on its own position information from the GPS signals until it reaches the wind turbine 40 to be inspected.

In step S103, the controller 30 of the drone 10 determines the current time as the first time point t1 and obtains the direction of the rotation axis KD of the blades 41A, 41B, and 41C at the first time point t1. Specifically, the controller 60 of the wind turbine 40 adjusts the yaw angle of the nacelle 43 so that the planes of rotation of the blades 41A, 41B, and 41C receive the wind head-on.

The controller 60 of the wind turbine 40 may transmit the direction of the rotation axis KD to the controller 30 of the drone 10.

Alternatively, the controller 30 of the drone 10 may determine the direction of the rotation axis KD of the blades 41A, 41B, and 41C. More specifically, the controller 30 uses the direct-angle 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 direction in which the drone is stopped (for example, the forward direction). The controller 30 detects the direction of the geomagnetic field using the geomagnetic sensor in the inertial measurement unit 32. Based on the detection result of the geomagnetic field, the controller 30 determines the current direction of the drone, and from this determination result, determines the current direction of the nacelle 43, i.e., the direction of the rotation axis KD of the blades 41A, 41B, and 41C.

In step S104, the controller 30 of the drone 10 causes the forward camera 18 to capture images of the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CA as shown in Figures 5, 6, 8, and 9.

In step S105, the controller 30 of the drone 10 causes the forward camera 18 to photograph the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CB as shown in Figures 5, 7, 8, and 9.

In step S106, the controller 30 of the drone 10 determines the location of damage to the blades 41A, 41B, and 41C based on the captured images obtained in steps S104 and S105.

(effect)
For example, one possible method is to have a drone automatically fly in a horizontal circle around the wind turbine to photograph the blades (horizontal flight). This method makes it easy to set a flight route. However, this method requires setting a flight route that avoids the drone colliding with the wind turbine and captures images of all parts of the blades. This increases the distance between the blades and the camera, resulting in lower quality images and longer inspection times.

By flying in this embodiment, the distance between the blade and the camera can be reduced by more than half compared to horizontal flight methods, which improves the quality of the captured images and shortens the inspection time.

Second Embodiment
(Drone flight path)
Fig. 11 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from an oblique direction relative to the wind turbine 40. Fig. 12 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from the front of the wind turbine 40. Fig. 13 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from the back of the wind turbine 40. Fig. 14 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from the side of the wind turbine 40. Fig. 15 is a diagram showing the flight path of the drone 10 in the second embodiment as viewed from above the wind turbine 40.

Figures 11 to 15 show circles CC, CD, CE, and CF as the flight path of drone 10.

Circle CC has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is a front circle on the same side of the tower 44 of wind turbine 40 as the blades. The radius of circle CC is rc. The distance between the plane of circle CC and the plane of rotation of blades 41A, 41B, and 41C is d3.

Circle CD has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is a front circle on the same side of the tower 44 of wind turbine 40 as the blades. The radius of circle CD is rd. The distance between the plane of circle CD and the plane of rotation of blades 41A, 41B, and 41C is d3.

The shortest distance between the circumference of circle CC and the circumference of circle CD is d5. The distance between the center of circle CC and the center of circle CD is d7.

Here, rc = rd may be set. The rotation axis KD may also pass through the midpoint of the line segment connecting the center of circle CC and the center of circle CD.

Circle CE has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is the rear circle on the opposite side of the blades with respect to tower 44 of wind turbine 40. The radius of circle CE is re. The distance between the plane of circle CE and the plane of rotation of blades 41A, 41B, and 41C is d4.

Circle CF has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is the rear circle on the opposite side of the blades with respect to tower 44 of wind turbine 40. The radius of circle CF is rf. The distance between the plane of circle CF and the plane of rotation of blades 41A, 41B, and 41C is d4.

The shortest distance between the circumference of circle CE and the circumference of circle CF is d6. The distance between the center of circle CE and the center of circle CF is d8.

Here, re = rf may also be set. The rotation axis KD may also pass through the midpoint of the line segment connecting the center of circle CE and the center of circle CF.

Here, rc = rd = re = rf may be used, and d3 = d4 may be used. Also, d5 = d6 may be used, and d7 = d8 may be used.

The vertical positions of the central axis SC of circle CC, the central axis SD of circle CD, the central axis SE of circle CE, and the central axis SF of circle CF may be the same as or different from the vertical position of the rotation axis KD.

The angle between the rotation axis KD and the line segment connecting the center of circle CC to point O where the rotation plane of blades 41A, 41B, and 41C intersect with the rotation axis KD is, for example, 45°, but may be any angle. The angle between the rotation axis KD and the line segment connecting the center of circle CD to point O where the rotation plane of blades 41A, 41B, and 41C intersect with the rotation axis KD is, for example, 45°, but may be any angle. The angle between the rotation axis KD and the line segment connecting the center of circle CE to point O where the rotation plane of blades 41A, 41B, and 41C intersect with the rotation axis KD is, for example, 45°, but may be any angle. The angle between the rotation axis KD and the line segment connecting the center of circle CF to point O where the rotation plane of blades 41A, 41B, and 41C intersect with the rotation axis KD is, for example, 45°, but may be any angle.

In this embodiment, as in the first embodiment, the flight path of this embodiment is more desirable when the direction of the rotation axis KD of blades 41A, 41B, and 41C does not change over time, or if it does change over time, the amount of change is small. In this case, the drone 10 flies along circles CC, CD, CE, and CF at times after the first time point t1, but the relative positional relationships of circles CC, CD, CE, and CF to the wind turbine 40 remain the same as at the first time point or do not change significantly.

(Inspection procedures for offshore wind turbines)
Below, based on the configuration 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 16 is a flowchart showing the inspection procedure for the wind turbine 40 in the second embodiment.

In step S201, 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.

In step S202, the inspector starts the engine 16 and generator 17 of the drone 10, and then causes the controller 30 of the drone 10 to begin an emergency inspection of the wind turbine 40, for example by executing a program. This causes the drone 10 to begin flying toward the wind turbine 40 to be inspected.

In step S203, the controller 30 of the drone 10 determines the current time as the first time point t1 and acquires the direction of the rotation axis KD of the blades 41A, 41B, and 41C at the first time point t1.

In step S204, the controller 30 of the drone 10 causes the forward camera 18 to photograph the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CC as shown in Figures 11, 12, 14, and 15.

In step S205, the controller 30 of the drone 10 causes the forward camera 18 to capture images of the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CD as shown in Figures 11, 12, 14, and 15.

In step S206, the controller 30 of the drone 10 causes the forward camera 18 to photograph the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CE as shown in Figures 11, 13, 14, and 15.

In step S207, the controller 30 of the drone 10 causes the forward camera 18 to photograph the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CF as shown in Figures 11, 13, 14, and 15.

In step S208, the controller 30 of the drone 10 determines the location of damage to the blades 41A, 41B, and 41C based on the captured images obtained in steps S204 to S207.

[Third embodiment]
(Drone flight path)
Fig. 17 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from an oblique direction relative to the wind turbine 40. Fig. 18 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from the front of the wind turbine 40. Fig. 19 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from the back of the wind turbine 40. Fig. 20 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from the side of the wind turbine 40. Fig. 21 is a diagram showing the flight path of the drone 10 in the third embodiment as viewed from above the wind turbine 40.

Figures 17 to 21 show circles CG, CH, CI, CJ, CK, and CL as the flight path of drone 10.

Circle CG has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is a front circle on the same side of the tower 44 of wind turbine 40 as the blades. The radius of circle CG is rg. The distance between the plane of circle CG and the plane of rotation of blades 41A, 41B, and 41C is d9.

Circle CH has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is a front circle on the same side of the tower 44 of wind turbine 40 as the blades. The radius of circle CH is rh. The distance between the plane of circle CH and the plane of rotation of blades 41A, 41B, and 41C is d9.

Circle CI has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is a front circle on the same side of the tower 44 of wind turbine 40 as the blades. The radius of circle CI is ri. The distance between the plane of circle CI and the plane of rotation of blades 41A, 41B, and 41C is d9.

The axis of rotation KD may or may not pass through the center of circle CH. The distance between the center of circle CG and the center of circle CH is d11. The distance between the center of circle CI and the center of circle CH is d12. Here, rg = rh = ri may be satisfied, or d11 = d12 may be satisfied.

Circle CJ has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is the rear circle on the opposite side of the blades with respect to the tower 44 of wind turbine 40. The radius of circle CJ is rj. The distance between the plane of circle CJ and the plane of rotation of blades 41A, 41B, and 41C is d10.

Circle CK has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is the rear circle on the opposite side of the blades with respect to tower 44 of wind turbine 40. The radius of circle CK is rk. The distance between the plane of circle CK and the plane of rotation of blades 41A, 41B, and 41C is d10.

Circle CL has a central axis in the same direction as the rotation axis KD of blades 41A, 41B, and 41C of wind turbine 40 at first time point t1, and is the rear circle on the opposite side of the blades with respect to tower 44 of wind turbine 40. The radius of circle CL is rl. The distance between the plane of circle CL and the plane of rotation of blades 41A, 41B, and 41C is d10.

The rotation axis KD may or may not pass through the center of circle CK. The distance between the center of circle CJ and the center of circle CK is d13. The distance between the center of circle CL and the center of circle CK is d14. Here, rj = rk = rl may be satisfied, or d13 = d14 may be satisfied.

Here, rg = rh = ri = rj = rk = rl may be used, or d9 = d10 may be used. Also, d11 = d12 = d13 = d14 may be used.

The vertical positions of the central axis SG of circle CG, the central axis SH of circle CH, the central axis SI of circle CI, the central axis SJ of circle CJ, the central axis SK of circle CK, and the central axis SL of circle CL may be the same as or different from the vertical position of the rotation axis KD.

In this embodiment, as in the first and second embodiments, the flight path of this embodiment is more desirable when the direction of the rotation axis KD of blades 41A, 41B, and 41C does not change over time, or if it does change over time, the amount of change is small. In this case, the drone 10 flies along the circles CG, CH, CI, CJ, CK, and CL at a time after the first time point t1, but the relative positional relationships of the circles CG, CH, CI, CJ, CK, and CL to the wind turbine 40 remain the same as at the first time point or do not change significantly.

(Inspection procedures for offshore wind turbines)
The inspection procedure for the wind turbine 40 in the third embodiment is similar to the inspection procedure for the wind turbine 40 in the first and second embodiments, and therefore the description will not be repeated.

In the first embodiment, the drone 10 was flown along the circumference of circle CA and the circumference of circle CB. In the second embodiment, the drone 10 was flown along the circumference of circle CC, the circumference of circle CD, the circumference of circle CE, and the circumference of circle CF. In the third embodiment, the drone 10 was flown along the circumference of circle CG, the circumference of circle CH, the circumference of circle CI, the circumference of circle CJ, the circumference of circle CK, and the circumference of circle CL.

The inspection procedure for the wind turbine 40 in the third embodiment is substantially the same as the inspection procedure for the wind turbine 40 in the first and second embodiments, with the only difference being the number and circumference of the flying circle. Therefore, a description of the inspection procedure for the wind turbine 40 in the third embodiment will not be repeated.

[Fourth embodiment]
In the first to third embodiments, it is assumed that the direction of the rotation axes KD of the blades 41A, 41B, and 41C does not change over time, or if it does change over time, the amount of change is small. In this embodiment, before the drone 10 flies each circumference, it acquires the direction of the rotation axes KD of the blades 41A, 41B, and 41C, and flies the circumference determined based on the acquired direction. This allows the drone 10 to fly a desired flight path even if the direction of the rotation axes KD of the blades 41A, 41B, and 41C changes over time.

Below, we will explain an example in which the flight path in the second embodiment is modified so that the drone 10 flies along a circle determined based on the direction of the rotation axis KD of the blades 41A, 41B, and 41C, which is acquired before the drone 10 flies along each circle. Similar modifications can also be made to the first and third embodiments.

Figure 22 is a flowchart showing the inspection procedure for the wind turbine 40 in the fourth embodiment.

In step S301, 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.

In step S302, the inspector starts the engine 16 and generator 17 of the drone 10, and then causes the controller 30 of the drone 10 to begin an emergency inspection of the wind turbine 40, for example by executing a program. This causes the drone 10 to begin flying toward the wind turbine 40 to be inspected.

In step S303, the controller 30 of the drone 10 determines the current time as the first time point t1 and obtains the direction of the rotation axis KD of the blades 41A, 41B, and 41C at the first time point t1.

In step S304, the controller 30 of the drone 10 causes the forward camera 18 to photograph the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of circle CC. Circle CC is a front circle whose central axis is in the same direction as the rotation axis KD of the blades 41A, 41B, and 41C of the wind turbine 40 at the first time point t1, and is on the same side of the tower 44 of the wind turbine 40 as the blades.

In step S305, the controller 30 of the drone 10 sets the current time as the second time point t2 and obtains the direction of the rotation axis KD of the blades 41A, 41B, and 41C at the second time point t2.

In step S306, the controller 30 of the drone 10 causes the forward camera 18 to photograph the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CD2. The circle CD2 is a front circle whose central axis is in the same direction as the rotation axis KD of the blades 41A, 41B, and 41C of the wind turbine 40 at the second time point t2, and is on the same side of the tower 44 of the wind turbine 40 as the blades.

In step S307, the controller 30 of the drone 10 sets the current time as the third time point t3 and obtains the direction of the rotation axis KD of the blades 41A, 41B, and 41C at the third time point t3.

In step S308, the controller 30 of the drone 10 causes the forward camera 18 to photograph the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CE2. The circle CE2 has a central axis in the same direction as the rotation axis KD of the blades 41A, 41B, and 41C of the wind turbine 40 at the third time point t3, and is a rear circle on the opposite side of the blades from the tower 44 of the wind turbine 40.

In step S309, the controller 30 of the drone 10 sets the current time as the fourth time point t4 and obtains the direction of the rotation axis KD of the blades 41A, 41B, and 41C at the fourth time point t4.

In step S310, the controller 30 of the drone 10 causes the forward camera 18 to photograph the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of circle CF2. Circle CF2 has a central axis in the same direction as the rotation axis KD of the blades 41A, 41B, and 41C of the wind turbine 40 at the fourth time point t4, and is a rear circle on the opposite side of the blades from the tower 44 of the wind turbine 40.

In step S311, the controller 30 of the drone 10 determines the location of damage to the blades 41A, 41B, and 41C based on the captured images obtained in steps S304, S306, S308, and S310.

Fifth Embodiment
In this embodiment, at the time of an emergency stop, the controller 60 of the wind turbine 40 adjusts the pitch angle 63 of the blades 41 so that the wind direction is parallel to the wind-receiving surfaces of the blades 41. This prevents the blades 41 from receiving lift from the wind, thereby preventing damage to the wind turbine 40.

Below, we will explain an example in which the above-mentioned control is added to the inspection procedure for the wind turbine 40 of the first embodiment.

Figure 23 is a flowchart showing the inspection procedure for the wind turbine 40 in the fifth embodiment.

In step S101, 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.

In step S401, the controller 60 of the wind turbine 40 adjusts the pitch angle 63 of the blades 41 so that the wind direction and the wind-receiving surface of the blades 41 are parallel.

In step S102, the inspector starts the engine 16 and generator 17 of the drone 10, and then causes the controller 30 of the drone 10 to begin an emergency inspection of the wind turbine 40, for example by running a program. This causes the drone 10 to begin flying toward the wind turbine 40 to be inspected.

In step S103, the controller 30 of the drone 10 determines the current time as the first time point t1 and obtains the direction of the rotation axis KD of the blades 41A, 41B, and 41C at the first time point t1.

In step S104, the controller 30 of the drone 10 causes the forward camera 18 to capture images of the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CA.

In step S105, the controller 30 of the drone 10 causes the forward camera 18 to capture images of the blades 41A, 41B, and 41C while flying the drone 10 along the circumference of the circle CB.

In step S106, the controller 30 of the drone 10 determines the location of damage to the blades 41A, 41B, and 41C based on the captured images obtained in steps S104 and S105.

The wind turbine inspection method described in the above embodiment is intended for emergency inspections, but can also be applied to regular inspections.

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 all modifications within the meaning and scope of the claims are intended to be embraced.

10 drone, 11 main body, 12 arm, 13 propeller motor, 14 propeller, 15 motor drive circuit, 16 engine, 17, 54 generator, 18, 18A, 18B, 20, 20A, 20B camera, 19, 21 gimbal, 22 legs, 23 propulsion mechanism, 24 sensor, 30, 60 controller, 31, 76 storage device, 32 inertial measurement unit, 33, 61, 78 transmitter/receiver, 34 receiver, 35 power circuit, 36 storage battery, 37 reader/writer, 38 recording medium, 40 wind turbine, 41A, 41B, 41C blade, 42 hub, 43 nacelle, 44 tower, 45 base, 46 floating body, 49 sea surface, 50 rotor shaft, 51 power transmission shaft, 52 gearbox, 53 Brake device, 55 Power cable, 56 Transformer, 57 Power cable, 62, 77 Antenna, 70 Terminal device, 72 RAM, 73 Non-volatile memory, 74 Display device, 75 Input device, 79 Bus.

Claims (8)

A method for inspecting wind power generation equipment, comprising:
A controller provided in the unmanned aerial vehicle acquires a direction of a rotation axis of a blade of the wind turbine at a first time point;
the controller causes a camera mounted on the unmanned aerial vehicle to photograph the wind turbine blades while moving the unmanned aerial vehicle along the circumference of at least one front circle that has a central axis in the same direction as the rotation axis of the wind turbine blades at the first time point and is on the same side as the blades with respect to the tower of the wind turbine;
A method for inspecting wind power generation equipment, comprising the steps of: the controller moving the unmanned aerial vehicle along the circumference of at least one back circle that has a central axis in the same direction as the rotation axis of the wind turbine blades at the first time point and is on the opposite side of the blades relative to the wind turbine tower, while causing a camera mounted on the unmanned aerial vehicle to photograph the wind turbine blades. The method for inspecting wind power generation equipment according to claim 1, wherein the vertical position of the central axis is the same as the vertical position of the rotation axis. The method for inspecting wind power generation equipment according to claim 1, wherein the at least one front-side circle includes two circles and the at least one back-side circle includes two circles. the at least one obverse circle is a first circle and a second circle;
the rotation axis passes through the midpoint of a line segment connecting the center of the first circle and the center of the second circle,
the at least one back circle is a third circle and a fourth circle;
The method for inspecting a wind power generation facility according to claim 3 , wherein the rotation axis passes through a midpoint of a line segment connecting the center of the third circle and the center of the fourth circle. A method for inspecting wind power generation equipment, comprising:
A controller provided in the unmanned aerial vehicle acquires a direction of a rotation axis of a blade of the wind turbine at a first time point;
the controller moving the unmanned aerial vehicle along a periphery of a first circle having a central axis in the same direction as the rotation axis at the first time point and on the same side of the wind turbine tower as the blades, and causing a camera mounted on the unmanned aerial vehicle to take inspection images of the wind turbine blades during the movement of the unmanned aerial vehicle;
a controller provided on the unmanned aerial vehicle acquiring a direction of a rotation axis of a blade of the wind turbine at a second time point;
the controller moving the unmanned aerial vehicle along a periphery of a second circle having a central axis in the same direction as the rotation axis at the second time point and on the same side of the wind turbine tower as the blades, and causing a camera mounted on the unmanned aerial vehicle to take inspection images of the wind turbine blades during the movement of the unmanned aerial vehicle;
a controller provided in the unmanned aerial vehicle acquiring a direction of a rotation axis of the blade of the wind turbine at a third time point;
the controller moving the unmanned aerial vehicle along a periphery of a third circle having a central axis in the same direction as the rotation axis at the third time point and on an opposite side of the blades with respect to the tower of the wind turbine, and causing a camera mounted on the unmanned aerial vehicle to take inspection images of the blades of the wind turbine during the movement of the unmanned aerial vehicle;
a controller provided in the unmanned aerial vehicle acquiring a direction of a rotation axis of the blade of the wind turbine at a fourth time point;
A method for inspecting wind power generation equipment, comprising the steps of: the controller moving the unmanned aerial vehicle along the periphery of a fourth circle having a central axis in the same direction as the rotation axis at the fourth time point and on the opposite side of the blades from the wind turbine tower; and causing a camera mounted on the unmanned aerial vehicle to take inspection images of the wind turbine blades while the unmanned aerial vehicle is moving. the blades of the wind turbine are rotatable;
6. The method for inspecting wind power generation equipment according to claim 1, further comprising a step in which, at the time of an emergency stop of the wind turbine, a controller of the wind turbine adjusts the pitch angle of the blades so that the direction of the wind and the wind-receiving surfaces of the blades are parallel. The method for inspecting wind power generation equipment described in any one of claims 1 to 5, 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 controller for controlling the propulsion mechanism and the camera;
The controller
Obtain the direction of the rotation axis of the wind turbine blades,
moving the unmanned aerial vehicle around at least one near-side circle having a central axis in the same direction as the axis of rotation of the wind turbine blades and on the same side of the wind turbine tower as the blades; and moving the unmanned aerial vehicle around at least one far-side circle having a central axis in the same direction as the axis of rotation of the wind turbine blades and on an opposite side of the wind turbine tower as the blades;
An unmanned aerial vehicle that causes a camera mounted on the unmanned aerial vehicle to take inspection images of the blades of the wind turbine while the unmanned aerial vehicle is moving.