Facility information acquisition system, flight control system, and facility information acquisition method

Abstract

To efficiently and safely acquire information on a facility using an unmanned aircraft.SOLUTION: A facility information acquisition system includes an unmanned aircraft, plural standard stations established at four or more different regions of a facility, and an information processor. The unmanned aircraft includes a flight controller, a first high-definition clock, a first wireless communication unit, and an information acquisition unit. Each of the plural standard stations includes a second high-definition clock and a second wireless communication unit. The information processor is connected to the flight controller so that the information processor can communicate with the flight controller. The information processor acquires a propagation time of a radio wave between the first wireless communication unit and the second wireless communication unit of each of the standard stations by means of a time space synchronization technology, and acquires a relative positional relation between the unmanned aircraft and the facility on the basis of the propagation time acquired for the respective standard stations. The flight controller controls the unmanned aircraft on the basis of the acquired positional relation so that the unmanned aircraft has a predetermined relative position relation to the facility.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an equipment information acquisition system, a flight control system, and an equipment information acquisition method. [Background technology]

[0002] Recently, the introduction of offshore wind power generation has progressed with the aim of achieving carbon neutrality and making renewable energy the main power source. Currently, inspection of offshore wind power generation facilities is carried out by having workers approach the surface of the blades using ropes or other tools and visually inspect them after the rotation of the blades is stopped, and various technologies have been proposed to improve the efficiency of inspection work and ensure safety.

[0003] For example, Patent Document 1 describes a method for inspecting wind power generation equipment located far away on the ocean using an autonomously flying unmanned aerial vehicle. In this method, the unmanned aerial vehicle is autonomously flown up to the sky above the wind turbine, the current orientation of the nacelle is determined above the wind turbine, the unmanned aerial vehicle is moved to a position directly facing the hub based on the determined current orientation of the nacelle, and the current rotation angle of the first blade is determined. Then, based on the determined rotation angle, the unmanned aerial vehicle is moved to an inspection start position for the first blade, and while moving the unmanned aerial vehicle from the inspection start position along the longitudinal direction of the first blade, an inspection image of the first blade is taken by the mounted camera.

[0004] For example, Patent Document 2 describes an inspection method for wind power generation equipment that is designed to enable proper visual inspection of the blades using a camera mounted on an unmanned aerial vehicle even when the blades of the wind turbine are rotating due to strong winds. In this inspection method, the angle of the blades of the wind turbine about the rotation axis is periodically determined using detection data from a distance measurement sensor attached to the nacelle of the wind turbine, and the rotation angle of the blades from the current time to a predetermined time later is estimated based on the change in the angle of the blades about the rotation axis up to the current time. Then, the flight path of the unmanned aerial vehicle along the blades from the current time to a predetermined time later is determined based on the current angle of the blades about the rotation axis and the estimated rotation angle of the blades, and the unmanned aerial vehicle is flown according to the determined flight path while the camera mounted on the unmanned aerial vehicle is caused to photograph the blades. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-108420 [Patent Document 2] JP 2023-42263 A [Non-patent literature]

[0006] [Non-Patent Document 1] Indoor position estimation based on relative distance measurement using radio waves (Hokuto Abe, Toshio Hirotsu), 81st National Convention of Information Processing Society of Japan, pp. 3-279 [Non-Patent Document 2] "Demonstration of wireless two-way interferometry (Wi-Wi)"; Nobuyasu Shiga, Kohta Kido, Satoshi Yasuda, Bhola Panta, Yuko Hanado, Seiji Kawamura, Hiroshi Hanado, Kenichi Takizawa, Masugi Inoue; IEICE Communications Express, Vol.6, No.2,77-82 Summary of the Invention [Problem to be solved by the invention]

[0007] There are two methods for installing wind power generation facilities on the ocean: a "fixed-bottom type" in which a foundation structure (piles, etc.) is installed on the seabed and a wind turbine is placed on top of the foundation structure, and a "floating type" in which a wind turbine is placed on a floating body. When trying to obtain information on a wind power generation facility using an unmanned aerial vehicle as in the above patent document, it is necessary to reliably prevent contact or collision between the unmanned aerial vehicle and the wind power generation facility. However, for the "floating type," since the wind turbine moves due to waves, ocean currents, wind conditions, etc., when inspecting the facility using an unmanned aerial vehicle, it is necessary to fly the unmanned aerial vehicle to follow the unexpected movement of the wind turbine, which requires advanced control technology. Even in the case of the "fixed-bottom type," the wind turbine is controlled as needed to keep the front of the blades facing upwind during operation of the wind power generation facility, so control similar to that of the "floating type" is required.

[0008] In the above-mentioned Patent Document 1, the rotation angle of the blades from the current time until a predetermined time later is estimated using detection data from a distance measuring sensor attached to the nacelle of the wind turbine, and the flight path of the unmanned aerial vehicle along the blades from the current time until the predetermined time later is determined. However, it is difficult and unfeasible to quickly track the direction of the distance measuring sensor according to unexpected movements of the wind power generation equipment caused by waves, ocean currents, wind conditions, etc.

[0009] In addition, in Patent Document 1, the self-location is determined using a Global Positioning System (GPS) or an Inertial Navigation System (INS), so the accuracy of the self-location determination is not necessarily sufficient, making it difficult to fly the unmanned aerial vehicle safely around wind power generation facilities.

[0010] The present invention has been made in consideration of the above background, and aims to provide a facility information acquisition system, a flight control system, and a facility information acquisition method that are capable of efficiently and safely acquiring facility information using an unmanned aerial vehicle. [Means for solving the problem]

[0011] One of the present inventions for solving the above problems is an equipment information acquisition system including an unmanned aerial vehicle, a plurality of reference stations provided at each of four or more different locations in the equipment from which information is to be acquired, and an information processing device having a processor and a memory device, wherein the unmanned aerial vehicle is equipped with a flight control device, a first high-precision clock, a first wireless communication device, and an information acquisition device for acquiring information of the equipment, and each of the plurality of reference stations is equipped with a second high-precision clock and a second wireless communication device, and the information processing device is communicatively connected to the flight control device via wired communication or wireless communication, acquires the propagation time of radio waves between the first wireless communication device and the second wireless communication device of each of the reference stations using space-time synchronization technology, and acquires the relative positional relationship between the unmanned aerial vehicle and the equipment based on the propagation time acquired for each of the reference stations, and the flight control device controls the unmanned aerial vehicle to be in a predetermined relative positional relationship with respect to the equipment based on the positional relationship.

[0012] Other problems and solutions disclosed in the present application will be made clear in the detailed description and drawings. Effect of the Invention

[0013] According to the present invention, facility information can be obtained efficiently and safely using an unmanned aerial vehicle. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a facility information acquisition system. [Diagram 2] FIG. 1 is a diagram showing the main configuration of a wind power generation facility. [Figure 3A] FIG. 1 is a diagram showing the main components of an unmanned aerial vehicle. [Figure 3B] FIG. 1 is a diagram showing the main functions of an unmanned aerial vehicle. [Figure 4A] FIG. 2 is a diagram showing main components of a relative position acquisition device. [Figure 4B]FIG. 2 is a diagram showing main functions of the relative position acquisition device. [Figure 5A] 13 is an example of transmission and reception time information (for each reference station). [Figure 5B] 13 is an example of propagation time information for each reference station. [Figure 5C] 13 is an example of distance variation information for each reference station. [Figure 5D] This is an example of relative position information. [Figure 6A] FIG. 2 is a diagram showing the main configuration of a reference station. [Figure 6B] FIG. 2 is a diagram for explaining main functions of a reference station. [Figure 7A] 4 is an example of a data structure of a first measurement signal. [Figure 7B] 13 is an example of a data structure of a second measurement signal. [Figure 8] 13 is a flowchart illustrating an equipment inspection process. [Figure 9] A diagram showing how the relative positional relationship between an unmanned aerial vehicle and a wind power generation facility is maintained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] At least the following matters will become apparent from the description of this specification and the accompanying drawings. Hereinafter, the present invention will be described in detail based on an embodiment thereof with reference to the accompanying drawings.

[0016] 1 shows a schematic configuration of an equipment information acquisition system 1 described as one embodiment of the present invention. As shown in the figure, the equipment information acquisition system 1 includes an unmanned aerial vehicle 10 that acquires information about a wind power generation facility 3 located on the ocean for inspection of the wind power generation facility 3, a plurality of reference stations 20 installed at predetermined positions of the wind power generation facility 3, and a monitoring and control device 40 that is installed on the ground or on a ship and controls and monitors the unmanned aerial vehicle 10 via wireless communication.

[0017] When flying around the wind power generation facility 3 for inspection, the unmanned aerial vehicle 10 is controlled by space-time synchronization technology to maintain a preset relative positional relationship with the wind power generation facility 3. The above positional relationship is set to a positional relationship required to prevent contact or collision between the unmanned aerial vehicle 10 and the wind power generation facility 3. Here, the space-time synchronization technology is a technology that performs bidirectional communication between wireless communication devices equipped with high-precision clocks such as small atomic clocks, offsets the influence of the difference in the high-precision clocks of the wireless communication devices, measures the propagation time of radio waves between the wireless communication devices with high precision, and acquires the fluctuation in the distance between the wireless communication devices and the relative positional relationship between the wireless communication devices with high precision (for example, see Non-Patent Document 1 and Non-Patent Document 2).

[0018] 2 shows the configuration of a typical wind power generation facility 3. The wind power generation facility 3 includes a floating body 30, a tower 31, a yaw axis control mechanism 32, a nacelle 33, a rotor shaft 34, blades 35, and a hub 36. Note that the reference station 20 is omitted in the figure.

[0019] The tower 31 is erected on a floating body 30 floating on the ocean. The floating body 30 is, for example, moored via a chain 62 to an anchor 61 (not shown in the figure) sunk into the ocean bottom, and is movable on the ocean up to the maximum extension range of the chain 62.

[0020] The nacelle 33 is mounted on a yaw axis control mechanism 32 provided near the top of the tower 31. The nacelle 33 houses a brake mechanism, a speed increasing mechanism, a main shaft, a pitch control mechanism, a generator, etc., which are provided at predetermined positions on a rotor shaft 34.

[0021] Three blades 35 and a hub 36 are provided on the other end of the rotor shaft 34. Electricity generated by the generator is transmitted to the substation 7 on land by a power transmission line 37 that passes through the yaw axis control mechanism 32, the inside of the tower 31, and the floating body 30 and extends into the sea.

[0022] A communication cable 38 for monitoring and controlling the wind power generation facility 3 is provided in addition to the power transmission line 37, and the other end of the communication cable 38 is connected to a wired communication device of a monitoring and control device 40 on the ground.

[0023] 1, the multiple reference stations 20 are installed at different locations in the wind power generation facility 3. Note that, in this embodiment, an example is shown in which four different reference stations 20 are installed at four predetermined locations in the wind power generation facility 3, but the number of the multiple reference stations 20 is not necessarily limited to four or more.

[0024] The unmanned aerial vehicle 10 and each reference station 20 are equipped with a high-precision clock and a wireless communication device for measuring the propagation time of radio waves between the unmanned aerial vehicle 10 and each reference station 20 with high precision using space-time synchronization technology. The equipment information acquisition system 1 measures the propagation time using space-time synchronization technology to acquire information indicating the variation in distance and the relative positional relationship between the unmanned aerial vehicle 10 and each reference station 20 in real time. Based on the acquired information, the equipment information acquisition system 1 controls the unmanned aerial vehicle 10 in real time so that the unmanned aerial vehicle 10 is maintained in a predetermined relative positional relationship with the wind power generation facility 3.

[0025] 3A shows the main components of the unmanned aerial vehicle 10. The unmanned aerial vehicle 10 is an unmanned aerial vehicle (a so-called drone) capable of autonomous flight or flight under remote control via wireless communication from a monitoring control device 40, and capable of stationary flight (hovering), such as a multicopter or helicopter. As shown in the figure, the unmanned aerial vehicle 10 includes a thrust generating device 101, a flight control device 102, various sensors 103, a communication device 104, a battery 105, an absolute position acquisition device 106, a relative position acquisition device 107, and an imaging device 108.

[0026] The thrust generating device 101 is a device that generates thrust for the unmanned aerial vehicle 10 to fly, and includes, for example, an electric motor, a motor control device (ESC: Electronic Speed ​​Controller), and a rotor (rotor, propeller). Note that, for example, a so-called internal combustion engine (glow engine, gasoline engine, diesel engine, etc.) that generates power by burning fuel may be used as the thrust generating device 101. Using an internal combustion engine as the thrust generating device 101 enables long-distance flight.

[0027] The flight control device 102 is configured using an information processing device (computer) such as a microcomputer having a processor (CPU (Central Processing Unit), MPU (Micro Processing Unit), etc.) and a storage device (RAM (Random Access Memory), ROM (Read Only Memory), NVRAM (Non Volatile Random Access Memory), etc.). The various functions of the flight control device 102 are realized by the processor of the flight control device 102 reading and executing programs stored in the storage device.

[0028] The flight control device 102 performs flight control and attitude control of the unmanned aerial vehicle 10. Note that flight control includes control (navigation) for flying the unmanned aerial vehicle 10 along a preset route. The flight control device 102 also controls and monitors various devices and functions equipped in the unmanned aerial vehicle 10. The flight control device 102 also controls the flight and attitude of the unmanned aerial vehicle 10 based on information acquired by various sensors 103 (hereinafter also referred to as "sensor information").

[0029] The various sensors 103 are sensors that acquire information necessary for the flight of the unmanned aerial vehicle 10, and are, for example, a speed sensor, an acceleration sensor, an angular velocity sensor, an angular acceleration sensor, a geomagnetic sensor, a microwave radar, a LiDAR (Light Detection and Ranging), etc. In addition, for example, the imaging device 108 may function as one of the various sensors 103. The various sensors 103 provide the sensor information acquired by the various sensors 103 to the flight control device 102 in real time.

[0030] The communication device 104 is a device that performs wireless communication with the remote control device (for example, a wireless communication device that uses frequencies in the 920 MHz, 2.4 GHz, or 5 GHz bands). The communication device 104 transmits, for example, video data captured by the imaging device 108 and information indicating the status (current position, attitude, etc.) of the unmanned aerial vehicle 10 to the remote control device at any time, for example, by wireless video transmission technology or telemetry communication.

[0031] Battery 105 is, for example, a lithium ion polymer secondary battery, and supplies the power necessary for the operation of each component of unmanned aerial vehicle 10. When thrust generating device 101 is configured using an internal combustion engine, unmanned aerial vehicle 10 may be provided with a generator that supplies charging power to battery 105.

[0032] The absolute position acquisition device 106 has a GNSS (Global Navigation Satellite System) (satellite positioning device (GNSS sensor)) and an inertial navigation device (EKF: Extended Kalman Filter), and acquires the current three-dimensional position of the unmanned aerial vehicle 10 on a map in real time (a position indicated by latitude, longitude, and altitude; hereinafter also referred to as the "absolute position") and provides it to the flight control device 102.

[0033] The relative position acquisition device 107 uses space-time synchronization technology to measure the propagation time of radio waves with high precision, thereby measuring the propagation time of radio waves between each reference station 20 with high precision, and based on the measured propagation time, determines the change in distance between the unmanned aerial vehicle 10 and each reference station 20 and the relative positional relationship (the relative positional relationship between the unmanned aerial vehicle 10 and the wind power generation facility 3 (hereinafter also referred to as "relative position"), and provides this to the flight control device 102. Details of the relative position acquisition device 107 will be described later.

[0034] In addition, the flight control device 102 controls the flight of the unmanned aerial vehicle 10 based on the absolute position provided by the absolute position acquisition device 106 and the relative position provided by the relative position acquisition device 107.

[0035] The photographing device 108 is a device (information acquisition device) that acquires information about the wind power generation facility 3, and is, for example, a video camera, a digital still camera, or a high-speed camera whose photographing conditions such as the photographing direction, angle of view, and exposure can be remotely controlled via wireless communication. If the inspection target is, for example, the rotating blade 35, the surface of the blade 35 can be photographed without blurring by using a high-speed camera.

[0036] The photographing device 108 generates video data and still image data (hereinafter referred to as "photographed data") of the part of the wind power generation facility 3 to be inspected (for example, the surface of the blade 35), and records the data in a recording medium such as a semiconductor memory device (NVRAM). The photographing device 108 also wirelessly transmits the photographed data to the monitoring control device 40.

[0037] 3B shows main functions of unmanned aerial vehicle 10. As shown in the figure, unmanned aerial vehicle 10 includes memory unit 110, flight control unit 120, communication control unit 125, and facility information acquisition unit 130.

[0038] The memory unit 110 stores flight status information 111, target relative position information 112, and photographing data 113.

[0039] Flight status information 111 includes flight information 1111, absolute position information 1112, and relative position information 1113. Flight information 1111 includes information on the flight status of unmanned aerial vehicle 10 acquired by various sensors 103 (flight speed of unmanned aerial vehicle 10, acceleration and angular acceleration currently acting on unmanned aerial vehicle 10, attitude of unmanned aerial vehicle 10, etc.) and time series information of the information. Absolute position information 1112 includes information indicating the absolute position of unmanned aerial vehicle 10 acquired by absolute position acquisition device 106 and time series information of the absolute position. Relative position information 1113 includes information indicating the relative position of unmanned aerial vehicle 10 acquired by relative position acquisition device 107 and time series information of the relative position.

[0040] The target relative position information 112 includes information indicating the position of the unmanned aerial vehicle 10 that should be maintained between the unmanned aerial vehicle 10 and the wind power generation facility 3 during inspection (hereinafter referred to as the "target relative position") (information expressed in a coordinate system set for the wind power generation facility 3 (information indicating the relative position with respect to the wind power generation facility 3)). The target relative position can be set, for example, from the monitoring control device 40 before or during the flight of the unmanned aerial vehicle 10. The flight control device 102 controls the flight of the unmanned aerial vehicle 10 based on information from the relative position acquisition device 107 so that the position of the unmanned aerial vehicle 10 is maintained at the target relative position. In addition, the target relative position can be changed, for example, from the monitoring control device 40 during the flight of the unmanned aerial vehicle 10, or dynamically by the unmanned aerial vehicle 10.

[0041] The photographed data 113 is photographed data (hereinafter also referred to as "facility information") acquired by the photographing device 108 by photographing a part or the like of the wind power generation facility 3 that is to be inspected.

[0042] The communication control unit 125 transmits and receives various types of information to and from the monitor control device 40 by wirelessly communicating with the monitor control device 40 .

[0043] The facility information acquisition unit 130 actively controls the imaging device 108 by autonomous control or passively in response to instructions from the monitoring control device 40, and captures an image of a subject (such as an inspection target) using the imaging device 108 to generate imaging data 113. The facility information acquisition unit 130 also updates the target relative position information 112 in response to instructions from the monitoring control device 40, and moves the unmanned aerial vehicle 10 to a position suitable for inspection (imaging). The facility information acquisition unit 130 also cooperates with the communication control unit 125 to transmit the imaging data (facility information) to the monitoring control device 40 as needed.

[0044] Fig. 4A shows the main components of the relative position acquisition device 107 shown in Fig. 3A. As shown in the figure, the relative position acquisition device 107 includes a processor 401, a storage device 402, a high-precision clock 403, and a wireless communication device 404.

[0045] The processor 401 is configured by, for example, a CPU or an MPU. The storage device 402 is, for example, a RAM, a ROM, an NVRAM, etc. The main functions of the relative position acquisition device 107 are realized by the processor 401 of the relative position acquisition device 107 reading and executing a program stored in the storage device 402.

[0046] The high-precision clock 403 is a timing device, such as a small atomic clock, that provides time with a high degree of precision applicable to space-time synchronization technology.

[0047] The wireless communication device 404 performs wireless communication with the reference station 20. The wireless communication device 404 performs wireless communication with the reference station 20 by using, for example, radio waves in the ultra-high frequency (UHF) band or the super high frequency (SHF) band.

[0048] 4B shows main functions of relative position acquisition device 107. As shown in the figure, relative position acquisition device 107 has the functions of a storage unit 410, a transmission / reception time acquisition unit 420, a time difference calculation unit 430, a propagation time calculation unit 435, a distance variation calculation unit 440, and a relative position calculation unit 445.

[0049] As shown in the figure, the memory unit 410 stores a first measurement signal 411, a second measurement signal (for each reference station) 412, transmission and reception time information (for each reference station) 414, propagation time information (for each reference station) 415, distance variation information (for each reference station) 416, and relative position information 417.

[0050] The transmission / reception time acquisition unit 420 acquires the transmission / reception times of radio waves by transmitting and receiving radio waves (measurement signals) to and from each reference station 20. As shown in the figure, the transmission / reception time acquisition unit 420 has a first measurement signal transmission unit 421 and a second measurement signal reception unit 422.

[0051] The first measurement signal transmitter 421 generates a measurement signal (hereinafter referred to as the "first measurement signal") for each reference station 20, and transmits the generated first measurement signal to each reference station 20. The first measurement signal includes the transmission time of the first measurement signal (hereinafter referred to as the "first transmission time") clocked by the high-precision clock 403.

[0052] The second measurement signal receiving unit 422 receives a second measurement signal (described later) transmitted from each reference station 20 in response to receiving the first measurement signal, and manages the received second measurement signal as a second measurement signal (for each reference station) 412. The second measurement signal includes an identifier of the reference station 20 that transmitted the second measurement signal (hereinafter referred to as a "reference station ID"), a first transmission time, a time at which the first measurement signal was received (hereinafter referred to as a "first reception time") clocked by a high-precision clock 603 (described later) included in the reference station 20, and a time at which each reference station 20 transmitted the second measurement signal (hereinafter referred to as a "second transmission time") clocked by the high-precision clock 603 (described later). The second measurement signal receiving unit 422 also acquires a reception time (hereinafter referred to as a "second reception time") of the second measurement signal transmitted from each reference station 20 clocked by the high-precision clock 403.

[0053] The transmission / reception time acquisition unit 420 manages the first transmission time, the first reception time, the second transmission time, and the second reception time acquired for each reference station 20 as described above in the transmission / reception time information (for each reference station) 414.

[0054] The time difference calculation unit 430 calculates, for each reference station 20, the time difference between the first transmission time and the first reception time (hereinafter referred to as the "first time difference") and the time difference between the second transmission time and the second reception time (hereinafter referred to as the "second time difference"), and manages the calculated first time difference and second time difference as transmission and reception time information (for each reference station) 414.

[0055] 5A shows an example of the transmission / reception time information (for each reference station) 414. As shown in the figure, the transmission / reception time information (for each reference station) 414 is composed of a record for each reference station 20 having each of the following items: a reference station ID 511, a first transmission time 512, a first reception time 513, a second transmission time 514, a second reception time 515, a first time difference 516, and a second time difference 517.

[0056] Of the above items, the reference station ID 511 stores the reference station ID. The first transmission time 512 stores the first transmission time. The first reception time 513 stores the first reception time acquired for the reference station 20. The second transmission time 514 stores the second transmission time acquired for the reference station 20. The second reception time 515 stores the second reception time acquired for the reference station 20. The first time difference 516 stores the first time difference. The second time difference 517 stores the second time difference.

[0057] Returning to FIG. 4B, the propagation time calculation unit 435 calculates the propagation time of the measurement signal (radio wave) of each reference station 20 based on the first time difference and the second time difference of the transmission and reception time information (for each reference station) 414, and manages the calculated propagation time of the radio wave of each reference station 20 as propagation time information (for each reference station) 415.

[0058] 5B shows an example of the propagation time information (for each reference station) 415. As shown in the figure, the propagation time information (for each reference station) 415 is composed of a record for each reference station 20 having items of a reference station ID 521 and a propagation time 522.

[0059] Of the above items, a reference station ID is stored in the reference station ID 521. A propagation time calculated for the reference station by the following formula (see, for example, Non-Patent Document 1) is stored in the propagation time 522. [Number 1] Propagation time = (1st time difference + 2nd time difference) / 2 Equation 1

[0060] Returning to FIG. 4B, the distance variation calculation unit 440 calculates the distance variation for each reference station 20 based on the propagation time information (for each reference station) 415, and manages the calculated distance variation for each reference station 20 as distance variation information 413 for each reference station.

[0061] 5C shows an example of distance variation information (for each reference station) 416. As shown in the drawing, the distance variation information (for each reference station) 416 is composed of a record for each reference station 20 having items of reference station ID 531 and distance variation 532.

[0062] Of the above items, the reference station ID is stored in the reference station ID 531. The distance change 532 stores the distance change for the reference station calculated by the following formula (see, for example, Non-Patent Document 1). [Number 2] Distance change = Propagation time × Speed ​​of light Equation 2

[0063] Returning to Fig. 4B, relative position calculation unit 445 determines the relative position of unmanned aerial vehicle 10 with respect to wind power generation facility 3 based on distance variation information (for each reference station) 416, and manages the determined relative position as relative position information 417. The relative position is determined, for example, by the method described in Non-Patent Document 1 (a method of formulating an equation relating to the distance variation measured at each reference station 20 and solving a simultaneous equation combining these equations).

[0064] Furthermore, the flight control device 102 of the unmanned aerial vehicle 10 controls the unmanned aerial vehicle 10 based on distance variation information (for each reference station) 416 and relative position information 417 so as to achieve the target relative position information 112.

[0065] 5D shows an example of the relative position information 417. As shown in the drawing, the relative position information 417 is made up of a record for each reference station 20 having the items of a reference station ID 541 and a relative position 542.

[0066] Of the above items, the reference station ID is stored in the reference station ID 541. The relative position 542 stores the relative position calculated for the reference station.

[0067] 6A shows the main configuration of the reference station 20. As shown in the figure, the reference station 20 includes a processor 601, a storage device 602, a high-precision clock 603, and a wireless communication device 604.

[0068] The processor 601 is configured with a CPU or an MPU. The storage device 602 is a RAM, a ROM, an NVRAM, etc. The main functions of the reference station 20 are realized by the hardware of the reference station 20, or by the processor 601 reading and executing a program stored in the storage device 602.

[0069] The high-precision clock 603 is a clock (time measuring device) that provides highly accurate time, such as a small atomic clock.

[0070] The wireless communication device 604 performs wireless communication with the reference station 20. The wireless communication device 604 performs wireless communication with the unmanned aerial vehicle 10, for example, using radio waves in the extremely high frequency band (UHF band) or the microwave band (SHF).

[0071] 6B shows main functions of the reference station 20. As shown in the figure, the reference station 20 has the functions of a storage unit 610, a first measurement signal receiving unit 620, and a second measurement signal transmitting unit 625.

[0072] As shown in the figure, a storage unit 610 stores a first measurement signal 611 and a second measurement signal 612 .

[0073] The first measurement signal receiving unit 620 receives the first measurement signal sent from the unmanned aerial vehicle 10 and manages the received first measurement signal as the first measurement signal 611.

[0074] 7A shows an example of the data structure of the first measurement signal 611. As shown in the figure, the first measurement signal 611 includes a first transmission time 711.

[0075] Returning to FIG. 6B, the second measurement signal transmitting unit 625 generates a second measurement signal and transmits the generated second measurement signal to the unmanned aerial vehicle 10.

[0076] 7B shows an example of the data structure of the second measurement signal 612. As shown in the figure, the second measurement signal 612 includes an identifier (reference station ID 751) of the reference station 20, a first transmission time 752 included in the first measurement signal 611, a reception time (first reception time 753) of the first measurement signal 611 clocked by a high-precision clock 603 provided in the reference station 20, and a transmission time (second transmission time 754) of the second measurement signal clocked by the high-precision clock 603 described later.

[0077] Fig. 8 is a flowchart explaining the processing (hereinafter referred to as "equipment inspection processing S800") performed in the equipment information acquisition system 1 when inspecting the wind power generation equipment 3 using the unmanned aerial vehicle 10. The equipment inspection processing S800 will be explained below with reference to the same figure. In the following explanation, it is assumed that the flight control of the unmanned aerial vehicle 10 is performed by remote monitoring control by the monitoring control device 40, or by autonomous control of the unmanned aerial vehicle 10. In the following explanation, it is assumed that the target relative position information 112 is set in advance by the monitoring control device 40 or the like.

[0078] First, the monitoring and control device 40 sends a command to the unmanned aerial vehicle 10, and in response to the command, the unmanned aerial vehicle 10 starts flying from a takeoff and landing site on the ground or on a ship toward the wind power generation facility 3 (S811). The monitoring and control device 40 and the unmanned aerial vehicle 10 acquire the current position of the unmanned aerial vehicle 10 from the takeoff and landing site to the vicinity of the wind power generation facility 3 using the absolute position acquisition device 106.

[0079] During the flight toward the site, unmanned aerial vehicle 10 monitors whether it has arrived near the site where wind power generation facility 3 is located (S812: NO).

[0080] Upon arriving at the site (S812: YES), the unmanned aerial vehicle 10 determines whether or not it can communicate with at least the number of reference stations 20 required to acquire the relative position of the unmanned aerial vehicle 10 (four in this example, hereinafter referred to as the "required number of reference stations") (S813). Note that the above determination is made based on, for example, whether or not the received electric field strength of radio waves transmitted from the reference station 20 (e.g., a beacon transmitted from the reference station 20 at a predetermined period) is equal to or greater than a preset threshold (hereinafter referred to as the "threshold electric field strength"), whether or not communication in accordance with a predetermined protocol can be established with the reference station 20, etc.

[0081] If the number of communicable reference stations 20 is equal to or greater than the required number of reference stations (S813: YES), the unmanned aerial vehicle 10 starts flight control based on information acquired by the relative position acquisition device 107 (S814). On the other hand, if the number of communicable reference stations 20 is less than the required number of reference stations (S813: NO), the unmanned aerial vehicle 10 corrects its own position (S830), and then the process returns to S813. Note that the correction of the own position is performed in a safe manner, for example, by temporarily moving in a direction away from the wind power generation facility 3, such as by moving to an upward retreat position, and then gradually approaching the wind power generation facility 3 while taking into account the accuracy (error) of the absolute position acquisition device 106 again.

[0082] When flight control based on information acquired by relative position acquisition device 107 is started (S814), unmanned aerial vehicle 10 flies toward target relative position information 112 (S815). Then, when unmanned aerial vehicle 10 arrives at the target relative position (S816: YES), unmanned aerial vehicle 10 maintains its own position at the target relative position (S817).

[0083] 9 shows the unmanned aerial vehicle 10 flying while maintaining its own position at a target relative position. As shown in the figure, even if the state (position, orientation, etc.) of the wind power generation facility 3 changes due to waves, ocean currents, wind conditions, etc., the unmanned aerial vehicle 10 flies while maintaining its relative positional relationship with the wind power generation facility 3.

[0084] Returning to FIG. 8, unmanned aerial vehicle 10 then starts inspection (acquisition of equipment information) of wind power generation equipment 3 (S818). For example, unmanned aerial vehicle 10 points the shooting direction of imaging device 108 toward a portion of wind power generation equipment 3 to be inspected (e.g., the surface of blade 35, etc.) and starts acquiring shooting data 113 for inspection. As described above, the setting of the target relative position may be changed chronologically during inspection, so that unmanned aerial vehicle 10 flies around wind power generation equipment 3 along the planned inspection route.

[0085] When the inspection work is completed (S819: YES), the unmanned aerial vehicle 10 determines whether or not to return (S820). For example, if there are any of the scheduled inspection locations that have not been inspected, the unmanned aerial vehicle 10 determines not to return (S820: NO), updates the target relative position to a position for inspecting the next inspection location (S840), and returns to the processing of S815. On the other hand, for example, if the inspection work at all of the scheduled inspection locations has been completed or the remaining amount (or remaining fuel) of the battery 105 is equal to or less than a predetermined amount, the unmanned aerial vehicle 10 determines to return (S820: YES), leaves the scene, and starts flight toward return by flight control based on the absolute position acquired by the absolute position acquisition device 106 (S821).

[0086] As described above in detail, the facility information acquisition system 1 of this embodiment acquires the propagation time of radio waves between each of the multiple reference stations 20 (second wireless communication device) installed at each of multiple different parts of the wind power generation facility 3, which is the facility to be inspected (information acquisition target), and the unmanned aerial vehicle 10 (first wireless communication device) using space-time synchronization technology, acquires the relative positional relationship between the unmanned aerial vehicle 10 and the wind power generation facility 3 based on the acquired propagation time, and controls the unmanned aerial vehicle 10 so that it has a predetermined relative positional relationship with the wind power generation facility 3 based on the acquired positional relationship. Therefore, even if the position or attitude of the wind power generation facility 3 changes due to the movement of the float 30, the rotation of the float 30, the rotation of the windmill, etc., it is possible to reliably prevent contact or collision between the unmanned aerial vehicle 10 and the wind power generation facility 3. In this way, according to the facility information acquisition system 1 of this embodiment, information on the wind power generation facility 3 can be acquired efficiently and safely using the unmanned aerial vehicle 10.

[0087] The above-described embodiment is for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit of the present invention, and equivalents thereof are also included in the present invention.

[0088] For example, the above describes the case where the equipment from which information is to be obtained by the unmanned aerial vehicle 10 is a wind power generation facility 3, but the above mechanism can also be applied to cases where the equipment from which information is to be obtained is equipment other than the wind power generation facility 3.

[0089] 1 etc., all four reference stations 20 are provided on the tower 31, but the installation positions of the reference stations 20 are not necessarily limited. For example, the reference stations 20 may be provided on the nacelle 33 on the premise that the nacelle 33 is not rotated during inspection (the direction (yaw axis) of the wind turbine is not changed by the yaw axis control mechanism 32).

[0090] In addition, when rotating the nacelle 33 during inspection, for example, by providing four or more reference stations 20 on the nacelle 33 and controlling the flight of the unmanned aerial vehicle 10 so that the relative positional relationship between the unmanned aerial vehicle 10 and the nacelle 33 is maintained at a specified positional relationship (a positional relationship separated by a safe distance from the nacelle 33 and blades 35), contact or collision between the unmanned aerial vehicle 10 and the wind turbine can be prevented. [Explanation of symbols]

[0091] 1 Facility information acquisition system, 3 Wind power generation facility, 10 Unmanned aerial vehicle, 101 Thrust generator, 102 Flight control device, 103 Various sensors, 104 Communication device, 105 Battery, 106 Absolute position acquisition device, 107 Relative position acquisition device, 403 High-precision clock, 404 Wireless communication device, 410 Memory unit, 411 First measurement signal, 412 Second measurement signal (per reference station), 414 Transmission / reception time information (per reference station), 415 Propagation time information (per reference station), 416 Distance variation information (per reference station), 417 Relative position information, 108 Photographing device, 110 Memory unit, 111 Flight status information, 1111 Flight information, 1112 Absolute position information, 1113 Relative position information, 112 Target relative position information, 113 Photographing data, 120 Flight control unit, 125 Communication control unit, 130 equipment information acquisition unit, 30 floating body, 31 tower, 32 yaw axis control mechanism, 33 nacelle, 34 rotor shaft, 35 blade, 20 reference station, 40 monitoring control device, 603 high-precision clock, 604 wireless communication device, 610 memory unit, 611 first measurement signal, 612 second measurement signal, 620 first measurement signal receiving unit, 625 second measurement signal transmitting unit, S800 equipment inspection processing

Claims

1. Unmanned aerial vehicles and A plurality of reference stations provided at four or more different locations in a facility from which information is to be acquired; An information processing device having a processor and a storage device; Including, The unmanned aerial vehicle includes a flight control device, a first high-precision clock, a first wireless communication device, and an information acquisition device that acquires information about the facility; each of the plurality of reference stations includes a second high-precision clock and a second wireless communication device; The information processing device includes: A communication device is connected to the flight control device via wired or wireless communication, acquiring a propagation time of radio waves between the first wireless communication device and each of the second wireless communication devices of the reference stations by a space-time synchronization technique; Obtaining a relative positional relationship between the unmanned aerial vehicle and the facility based on the propagation time obtained for each of the reference stations; The flight control device controls the unmanned aerial vehicle to have a predetermined relative positional relationship with respect to the facility based on the positional relationship. Facility information acquisition system.

2. The facility information acquisition system according to claim 1, The information processing device includes: acquiring a first transmission time, which is a transmission time of a radio wave transmitted from the first wireless communication device, by the first high-precision clock; acquiring a first reception time, which is a time at which the radio wave is received by the second wireless communication device, using the second high-precision clock; acquiring a second transmission time, which is a transmission time of the radio wave transmitted from the second wireless communication device, by the second high-precision clock; acquiring a second reception time, which is a time when the radio wave is received by the first wireless communication device, using the first high-precision clock; determining the propagation time based on a first time difference which is a time difference between the first reception time and the first transmission time, and a second time difference which is a time difference between the second reception time and the second transmission time; Facility information acquisition system.

3. The facility information acquisition system according to claim 1, The facility is an offshore wind power generation facility. Facility information acquisition system.

4. The facility information acquisition system according to claim 1, The information acquisition device is an imaging device that images a part of the equipment to be inspected. Facility information acquisition system.

5. The facility information acquisition system according to claim 1, The information processing device is mounted on the unmanned aerial vehicle. Facility information acquisition system.

6. The facility information acquisition system according to claim 1, The unmanned aerial vehicle is a multicopter or a helicopter. Facility information acquisition system.

7. Unmanned aerial vehicles and A plurality of reference stations provided at four or more different locations in a facility from which information is to be acquired; An information processing device having a processor and a storage device; Including, The unmanned aerial vehicle includes a flight control device, a first high-precision clock, and a first wireless communication device; each of the plurality of reference stations includes a second high-precision clock and a second wireless communication device; The information processing device includes: A communication device is connected to the flight control device via wired or wireless communication, acquiring a propagation time of radio waves between the first wireless communication device and each of the second wireless communication devices of the reference stations by a space-time synchronization technique; Obtaining a relative positional relationship between the unmanned aerial vehicle and the facility based on the propagation time obtained for each of the reference stations; The flight control device controls the unmanned aerial vehicle to have a predetermined relative positional relationship with respect to the facility based on the positional relationship. Flight control system.

8. Unmanned aerial vehicles and A plurality of reference stations provided at four or more different locations in a facility from which information is to be acquired; An information processing device having a processor and a storage device; Including, The unmanned aerial vehicle includes a flight control device, a first high-precision clock, a first wireless communication device, and an information acquisition device that acquires information about the facility; each of the plurality of reference stations is configured to include a second high-precision clock and a second wireless communication device; The information processing device is communicatively connected to the flight control device via wired communication or wireless communication. A method for controlling a facility information acquisition system, comprising: The information processing device, acquiring a propagation time of radio waves between the first wireless communication device and each of the second wireless communication devices of the reference stations by a space-time synchronization technique; obtaining a relative positional relationship between the unmanned aerial vehicle and the facility based on the propagation times obtained for each of the reference stations; and a step of controlling the flight control device so that the unmanned aerial vehicle is in a predetermined relative positional relationship with respect to the facility based on the positional relationship; A control method for a facility information acquisition system.

9. A control method for the facility information acquisition system according to claim 8, The information processing device, acquiring a first transmission time, which is a transmission time of a radio wave transmitted from the first wireless communication device, by the first high-precision clock; acquiring a first reception time, which is a reception time of the radio wave by the second wireless communication device, using the second high-precision clock; acquiring, by the second high-precision clock, a second transmission time which is a transmission time of a radio wave transmitted from the second wireless communication device; acquiring, by the first high-precision clock, a second reception time which is a time at which the radio wave is received by the first wireless communication device; and determining the propagation time based on a first time difference that is a time difference between the first reception time and the first transmission time, and a second time difference that is a time difference between the second reception time and the second transmission time; A control method for a facility information acquisition system.

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