WO2021192220A1

WO2021192220A1 - Flight control system

Info

Publication number: WO2021192220A1
Application number: PCT/JP2020/014020
Authority: WO
Inventors: 千大和氣; 宏記加藤; 洋柳下
Original assignee: 株式会社ナイルワークス
Priority date: 2020-03-27
Filing date: 2020-03-27
Publication date: 2021-09-30
Also published as: JPWO2021192220A1

Abstract

The present invention reduces the risk of collisions when a plurality of unmanned aerial vehicles fly in formation.　This flight control system comprises: a drone 100a which flies over an agricultural field 403; a drone 100b which flies alongside the drone 100b; and a server 405 provided with a determination means which determines a first flight plan indicating a flight route and a flight mode for the drone 100a, and a second flight plan indicating a flight route and a flight mode for the drone 100b. The determination means determines the first flight plan and the second flight plan so that a distance at least equal to a prescribed threshold value is always maintained between the drone 100a, which flies according to the first flight plan, and the drone 100b, which flies according to the second flight plan.

Description

Flight control system

The present invention relates to a flight control system for flying an unmanned aerial vehicle such as a drone and causing the unmanned aerial vehicle to perform various tasks.

The application of small helicopters (multicopters) called drones is advancing. One of the important application fields is spraying chemicals such as pesticides and liquid fertilizers on agricultural land (fields). Especially in agricultural land where the site area is relatively small, it is often suitable to use drones instead of manned airplanes and helicopters.

Patent Document 1 describes an aerial photograph of agricultural land using a drone, specifies an area and amount to which pesticides should be sprayed based on the obtained image, and efficiently sprays the specified amount of pesticides to the specified area. A pesticide spraying method has been proposed in which a drone is used to spray pesticides according to the plan.

Japanese Unexamined Patent Publication No. 2018-1112429

Regarding the flight control system for drones, two or more drones are planned above the target area such as agricultural land (field) where crops are planted as a formation that maintains the positional relationship in their three-dimensional space. There is a need to fly according to the flight route.
For example, there is such a need in the following situations.

(1) When the first drone (a large drone weighing several tens of kilograms) flies over several tens of centimeters of agricultural products, a downdraft generated by the lift generating means of the drone (hereinafter, "downwash") A second drone (for example, a small drone weighing several kilograms) that flies to the side of the first drone takes a picture of the stock of agricultural products such as rice that has been knocked down by the camera. , I want to get an image of the origin of the crop from a better angle taken from the first drone.

(2) When the first drone (a large drone weighing several tens of kilograms) flies over several tens of centimeters of crops such as rice planted in paddy fields, the downwash generated by the drone brings it to the surface of the water. By temporarily moving floating plants (floating grass, algae, etc., hereinafter referred to as "floating plants on the water surface"), the water surface near the crops is exposed, and the subsequent second drone is exposed to the water surface. By spraying chemicals such as pesticides and fertilizers (especially granular chemicals), we want to eliminate chemicals that fall on floating plants as much as possible and dissolve them in water.

(3) When the first drone (a large drone weighing several tens of kilograms) flies over several tens of centimeters of crops such as rice planted in paddy fields, the drone is produced by downwashing the crops. I would like to blow off the adhering dew and spray chemicals such as pesticides on the crops without dew on the subsequent second drone.

However, if two or more drones fly in close proximity, the risk of collision increases. For example, when two drones fly in a front-to-back positional relationship, if the preceding drone slows down due to a change of direction or the like, there is a risk that the succeeding drone will come too close to the preceding drone and collide. Also, when two drones fly while maintaining the positional relationship between the left and right, if the drone on the left changes the flight direction to the right, there is a risk of colliding with the drone on the right too close.

An object of the present invention is to provide a means for reducing the risk of collision of two or more drones when they fly according to a predetermined flight route.

The flight control system according to the present invention includes a first flight plan showing a flight route when a first unmanned aircraft flies over a target area and a mode of flight along the flight route, and a second unmanned aircraft. A deciding means for determining a flight route when flying over the target area and a second flight plan indicating a mode of flight along the flight route is provided, and the deciding means flies according to the first flight plan. The first unmanned aircraft and the second unmanned aircraft flying in accordance with the second flight plan keep a distance equal to or greater than a predetermined threshold when flying over the target area. The flight plan and the second flight plan are determined.

It is a figure which shows the structure of the flight control system which is 1st Embodiment of this invention. It is a figure which shows the structure of the drone in the same embodiment. It is a figure which shows the structure of the drone. It is a figure which shows the structure of the drone. It is a figure which shows the structure of the drone. It is a figure which shows the structure of the drone. It is a block diagram which shows the structure of the drone. It is a block diagram which shows the functional structure of the data processing apparatus in the drone. It is a block diagram which shows the structure of the server in the same embodiment. It is a block diagram which shows the functional structure of the CPU of the server. It is a flowchart of the process for generating a flight plan in the same embodiment. It is a figure which illustrates the flight route of the drone in the same embodiment, and the flight mode of the drone along this flight route. It is a figure which illustrates the time change of the flight speed of two drones in the draft of the flight plan of the same embodiment. It is a figure which illustrates the time change of the flight distance of two drones in the draft of the flight plan of the same embodiment. It is a figure which illustrates the time change of the distance between drones in the draft of the flight plan of the same embodiment. It is a figure which illustrates the flight route and the flight mode along the flight route in the flight plan of the same embodiment. It is a figure which illustrates the time change of the flight speed of two drones in the flight plan of the same embodiment. It is a figure which illustrates the time change of the flight distance of two drones in the flight plan of the same embodiment. It is a figure which illustrates the time change of the distance between drones in the flight plan of the same embodiment. It is a figure which illustrates the high degree of time change of two drones in the 2nd Embodiment of this invention. It is a figure which illustrates the flight route of two drones in the 3rd Embodiment of this invention.

Hereinafter, a mode for carrying out the present invention will be described with reference to the drawings. All figures are illustrations. In the following detailed description, certain details are given for illustration purposes and to facilitate a complete understanding of the disclosed embodiments. However, embodiments are not limited to these particular details. Also, to simplify the drawings, well-known structures and devices are outlined.

<First Embodiment>
FIG. 1 is a diagram showing a configuration of a flight control system according to a first embodiment of the present invention. The field 403 is an agricultural land such as a rice field or a field where crops are cultivated. The base station 404 has both a function as a master unit for Wi-Fi communication and a function as an RTK-GPS base station. The user terminal 401 is a terminal operated by the agricultural worker 402 who is a user, and communicates with the

drones

100a and 100b or the server 405 via the base station 404 and the network. The user terminal 401 may be realized by a mobile information device such as a general tablet terminal that executes a computer program.

Drones

100a and 100b are unmanned aerial vehicles each equipped with an autonomous flight function. The

drones

100a and 100b take off from the departure / arrival point 406 outside the field 403 according to the flight plan given in advance, perform the predetermined work while flying in the field 403, and after the work is completed or need to be charged. When it becomes, it returns to the departure and arrival point 406.

The server 405 is typically a group of computers and related software operated on a cloud service. Before the

drones

100a and 100b start flying, the server 405 determines the flight route of the drone 100a and a first flight plan showing the mode of flight along the flight route, and the flight route of the drone 100b and the flight route of the drone 100b. It has a function of determining a second flight plan indicating the mode of flight along the flight route, and giving the first flight plan to the drone 100a and the second flight plan to the drone 100b. Further, the server 405 has a function of relaying various instructions transmitted from the user terminal 401 to the

drones

100a and 100b.

In the present embodiment, the field 403 is a paddy field. In the present embodiment, the first unmanned aerial vehicle, the drone 100a, plays a role of repelling floating plants by downwash while flying 30 cm above the crops planted in the field 403. In addition, the second unmanned aerial vehicle, the drone 100b, lags the height of 1 m above the rice field by 2 m from the drone 100a, and while flying on the same flight route as the drone 100a, the floating plants on the surface of the water are repelled. A chemical that dissolves in water (for example, granular pesticides and fertilizers) is sprayed at a spray rate according to the flight speed (so that the amount of chemical sprayed on the farmland per unit area is constant). The server 405 has a predetermined positional relationship in which the

drones

100a and 100b are in a three-dimensional space before the

drones

100a and 100b start flying (in this case, the drone 100b is located 70 cm above the drone 100a 2 m later). ) Is always maintained, and the first flight plan of the drone 100a and the second flight plan of the drone 100b are determined. These flight plans include a flight route that is a trajectory of the position of the drone that changes in three-dimensional space, and information indicating the flight mode of the drone at a plurality of positions along the flight route, specifically, the flight speed. ..

In this embodiment, the

drones

100a and 100b have the same configuration. Therefore, in the following, when it is not necessary to distinguish between the two, the

drones

100a and 100b are collectively referred to as the drone 100. Hereinafter, the drone 100 will be described. In this specification, the drone is regardless of the power means (electric power, prime mover, etc.) and the maneuvering method (wireless or wired, autonomous flight type, manual maneuvering type, etc.). It refers to all unmanned aerial vehicles with multiple rotors.

As shown in FIGS. 2 to 6, the rotor blades 101-1a, 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, 101-4a, 101-4b (also referred to as rotors) are It is a means for flying the drone 100, and is equipped with eight aircraft (four sets of two-stage rotor blades) in consideration of the balance between flight stability, aircraft size, and battery consumption.

The motors 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 102-4a, 102-4b are the rotary blades 101-1a, 101-1b, 101-2a, 101-. It is a means for rotating 2b, 101-3a, 101-3b, 101-4a, 101-4b (typically an electric motor, but may be a motor or the like), and one machine is provided for one rotary blade. Has been done. The motor 102 is an example of a propulsion device. The upper and lower rotors (eg, 101-1a and 101-1b) in one set, and the corresponding motors (eg, 102-1a and 102-1b), are used for drone flight stability and the like. The axes are on the same straight line and rotate in opposite directions. Although some rotor blades 101-3b and motor 102-3b are not shown, their positions are self-explanatory and are in the positions shown if there is a left side view. As shown in FIGS. 3 and 4, the radial members for supporting the propeller guards provided so that the rotor does not interfere with foreign matter have a rather wobbling structure rather than a horizontal one. This is to encourage the member to buckle outside the rotor in the event of a collision and prevent it from interfering with the rotor.

The drug nozzles 103-1, 103-2, 103-3, 103-4 are means for spraying the drug downward, and are provided with four machines. In the specification of the present application, the term "pharmaceutical" generally refers to a liquid or powder sprayed on a field such as a pesticide, a herbicide, a liquid fertilizer, an insecticide, a seed, and water.

The drug tank 104 is a tank for storing the sprayed drug, and is provided at a position close to the center of gravity of the drone 100 and at a position lower than the center of gravity from the viewpoint of weight balance. The drug hoses 105-1, 105-2, 105-3, 105-4 are means for connecting the drug tank 104 and the drug nozzles 103-1, 103-2, 103-3, 103-4, and are rigid. It may be made of the above-mentioned material and also serve to support the drug nozzle. The pump 106 is a means for discharging the drug from the nozzle.

FIG. 7 shows a block diagram showing the control function of the drone 100. The data processing device 501 is a component that controls the entire drone, and may be an embedded computer including a CPU, a memory, related software, and the like. The data processing device 501 uses motors 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 104-a, 104 via a control means such as ESC (Electronic Speed Control). The flight of the drone 100 is controlled by controlling the rotation speed of −b. The actual rotation speeds of the motors 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 104-a, 104-b are fed back to the data processing device 501, and the normal rotation is achieved. It is configured to monitor whether it is being performed. Alternatively, the rotary blade 101 may be provided with an optical sensor or the like so that the rotation of the rotary blade 101 is fed back to the data processing device 501.

The software used by the data processing device 501 can be rewritten through a storage medium or the like for function expansion / change, problem correction, etc., or through communication means such as Wi-Fi communication or USB. In this case, protection is performed by encryption, checksum, electronic signature, virus check software, etc. so that rewriting by unauthorized software is not performed. Further, a part of the calculation process used by the data processing device 501 for control may be executed by another computer existing on the user terminal 401, the server 405, or somewhere else. Since the data processing device 501 is of high importance, some or all of its components may be duplicated.

The battery 502 is a means for supplying electric power to the data processing device 501 and other components of the drone, and may be rechargeable. The battery 502 is connected to the data processing device 501 via a fuse, a power supply unit including a circuit breaker, or the like. The battery 502 may be a smart battery having a function of transmitting its internal state (storage amount, integrated usage time, etc.) to the data processing device 501 in addition to the power supply function.

The data processing device 501 can communicate with the user terminal 401 and the server 405 via the Wi-Fi slave unit 503 and further via the base station 404. In this case, the communication may be encrypted so as to prevent fraudulent acts such as interception, spoofing, and device hijacking. As described above, the base station 404 also has a Wi-Fi communication function and a function as an RTK-GPS base station. Therefore, by combining the signal of the RTK base station and the signal from the GPS positioning satellite, the GPS module 504 can measure the absolute position of the drone 100 with an accuracy of about 2 cm. Since the GPS module 504 is so important, it may be duplicated / multiplexed, and each redundant GPS module 504 should use a different satellite in order to cope with the failure of a specific GPS satellite. It may be controlled.

The 6-axis gyro sensor 505 is a means for measuring the acceleration of the drone body in three directions orthogonal to each other (further, a means for calculating the velocity by integrating the acceleration). The 6-axis gyro sensor 505 is a means for measuring the change in the attitude angle of the drone body in the above-mentioned three directions, that is, the angular velocity. The geomagnetic sensor 506 is a means for measuring the direction of the drone body by measuring the geomagnetism. The barometric pressure sensor 507 is a means for measuring barometric pressure, and can also indirectly measure the altitude of the drone. The laser sensor 508 is a means for measuring the distance between the drone body and the ground surface by utilizing the reflection of the laser beam, and may be an IR (infrared) laser. The sonar 509 is a means for measuring the distance between the drone body and the ground surface by utilizing the reflection of sound waves such as ultrasonic waves. These sensors may be selected according to the cost target and performance requirements of the drone. Further, a gyro sensor (angular velocity sensor) for measuring the inclination of the airframe, a wind power sensor for measuring the wind power, and the like may be added. Further, these sensors may be duplicated or multiplexed. When there are a plurality of sensors for the same purpose, the data processing device 501 may use only one of them, and when it fails, it may be switched to an alternative sensor for use. Alternatively, a plurality of sensors may be used at the same time, and if the measurement results do not match, it may be considered that a failure has occurred.

The flow rate sensor 510 is a means for measuring the flow rate of the drug, and is provided at a plurality of locations on the path from the drug tank 104 to the drug nozzle 103. The liquid drainage sensor 511 is a sensor that detects that the amount of the drug has fallen below a predetermined amount.

The visible light camera 512a, the first spectrum camera 512b, and the second spectrum camera 512c are cameras for photographing agricultural products, respectively, and function as measuring means for measuring the physical condition of the agricultural products planted on the agricultural land. .. Here, the visible light camera 512a captures the entire wavelength band of sunlight reflected by the crop. Further, the first spectrum camera 512b disperses and photographs red light, for example, a component in a wavelength band near 680 nm in the sunlight reflected by the agricultural product. In addition, the second spectrum camera 512c disperses and photographs near-infrared light, for example, a component in a wavelength band near 780 nm in the sunlight reflected by the agricultural crop. In the drone 100, the morbidity of crops is diagnosed based on the images obtained from the first spectrum camera 512b and the second spectrum camera 512c.

Obstacle detection camera 513 is a camera for detecting drone obstacles. The switch 514 is a means for the agricultural worker 402 using the drone 100 to make various settings. The obstacle contact sensor 515 is a sensor for detecting that the drone 100, particularly its rotor or propeller guard portion, has come into contact with an obstacle such as an electric wire, a building, a human body, a standing tree, a bird, or another drone. .. The cover sensor 516 is a sensor that detects that the operation panel of the drone 100 and the cover for internal maintenance are in the open state. The drug injection port sensor 517 is a sensor that detects that the injection port of the drug tank 104 is in an open state. These sensors may be selected according to the cost target and performance requirements of the drone, and may be duplicated or multiplexed. Further, a sensor may be provided at the base station 404 outside the drone 100, the user terminal 401, or some other place, and the read information may be transmitted to the drone. For example, a wind power sensor may be provided in the base station 404 to transmit information on the wind power and the wind direction to the drone 100 via Wi-Fi communication.

The data processing device 501 transmits a control signal to the pump 106 to adjust the drug discharge amount and stop the drug discharge. The current state of the pump 106 (for example, the number of revolutions) is fed back to the data processing device 501. Further, the data processing device 501 is a position measuring means for measuring the three-dimensional position of the drone 100 by using the Wi-Fi slave unit 503, the GPS module 504, the geomagnetic sensor 506, the pressure sensor 507, the laser sensor 508 and the sonar 509. It has the function as. Further, the data processing device 501 is based on the three-dimensional position of the drone 100 measured by the position measuring means and the posture of the drone 100 measured by the 6-axis gyro sensor 505, and the visible light camera 512a and the first spectrum camera 512b. It also has a function as a planting position specifying means for specifying a planting position (or region) of an agricultural product photographed by each of the second spectrum cameras 512c.

LED107 is a display means for notifying the operator of the drone of the state of the drone. As the display means, a display means such as a liquid crystal display may be used instead of the LED or in addition to the LED. The buzzer 518 is an output means for notifying the state of the drone (particularly the error state) by an audio signal. The Wi-Fi slave unit function 519 is an optional component for communicating with an external computer or the like for transferring software, for example, in addition to the user terminal 401. In place of or in addition to the Wi-Fi slave function, other wireless communication means such as infrared communication, Bluetooth®, ZigBee®, NFC, or wired communication means such as USB connection. You may use it. The speaker 520 is an output means for notifying the state of the drone (particularly the error state) by means of a recorded human voice, synthetic voice, or the like. Since it may be difficult to see the visual display of the drone 100 in flight depending on the weather conditions, it is effective to convey the situation by voice in such a case. The warning light 521 is a display means such as a strobe light for notifying the state of the drone (particularly the error state). These input / output means may be selected according to the cost target and performance requirements of the drone, and may be duplicated or multiplexed.

FIG. 8 is a block diagram showing a functional configuration of the data processing device 501 of the drone 100a, which is the first unmanned aerial vehicle. As shown in FIG. 8, the data processing device 501 includes a CPU 710 and a storage unit 720 including a non-volatile memory and a volatile memory. In the box showing the CPU 710, a communication processing unit 711 and a flight control unit 712 are shown. These are the functions realized by the CPU 710 executing the program in the storage unit 720.

The first flight plan 721 is stored in the storage unit 720 of the drone 100a, which is the first unmanned aerial vehicle. The first flight plan 721 is given by the server 405 and stored in the storage unit 720. The first flight plan 721 provides information indicating the flight route on the field 403 to which the drone 100a should fly, and information indicating the mode of flight at a plurality of positions along the flight route, specifically, the flight speed. include. Although not shown, the second flight plan is stored in the storage unit 720 of the drone 100b, which is the second unmanned aerial vehicle.

In the CPU 710, the communication processing unit 711 is a means for communicating with the server 405 or the user terminal 401. The communication processing unit 711 downloads the first flight plan 721 from the server 405 to the storage unit 720. The flight control unit 712 controls the drone 100a to fly according to the first flight plan 721 in the storage unit 720 in response to an instruction given from the user terminal 401 via the server 405. Specifically, the flight control unit 712 has motors 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, for flying the drone 100a in accordance with the first flight plan 721. The rotation speeds of 104-a and 104-b are controlled.

The configuration of the data processing device 501 has been described above using the drone 100a as an example, but the data processing device 501 of the drone 100b is also the same as the data processing device 501 of the drone 100a. However, in the data processing device 501 of the drone 100b, the second flight plan is stored in the storage unit 720. In the drone 100b, the flight control unit 712 causes the drone 100b to fly according to this second flight plan.

FIG. 9 is a block diagram showing the configuration of the server 405. Note that FIG. 9 shows the user terminal 401, the

drones

100a and 100b together with the server 405 in order to make the function of the server 405 easy to understand.

As shown in FIG. 9, the server 405 includes a CPU 810 that controls the whole, a storage unit 820 that stores programs and data, and a communication unit 830 that communicates with communication partners such as user terminals 401,

drones

100a and 100b. include. The CPU 810 is an aggregate of CPUs of a plurality of computers provided by a cloud service. Further, the storage unit 820 is an aggregate of storage devices owned by a plurality of computers provided by the cloud service.

FIG. 10 is a block diagram showing a functional configuration of the CPU 810. In addition, in FIG. 10, various data stored in the storage unit 820 are shown together with the CPU 810 in order to make the functional configuration of the CPU 810 easy to understand.

In FIG. 10, the communication processing unit 811 and the flight plan generation unit 812 are shown in the box showing the CPU 810. These are functions realized by the CPU 810 executing a program (not shown) in the storage unit 820.

The communication processing unit 811 is a means for controlling communication with communication partners such as the user terminal 401, the

drones

100a and 100b shown in FIG. The flight plan generation unit 812 is a determination means for determining the first flight plan 822a and the second flight plan 822b. The flight plan generation unit 812 is a first flight plan draft 821a and a second unmanned aerial vehicle for the drone 100a, which is the first unmanned aerial vehicle, by referring to the map data 823 in the storage unit 820. A draft second flight plan 821b for the drone 100b is generated and stored in the storage unit 820. Here, the map data 823 includes information indicating the latitude and longitude of a plurality of positions on the boundary line surrounding the area where the crop is planted in the field 403. The flight plan generation unit 812 is the first flight plan draft 821a and the second flight plan showing the flight route for comprehensively flying over the area where the agricultural crop is planted and the mode of flight along the flight route. Generate a draft flight plan 821b. Then, based on these drafts 821a and 821b, the flight plan generation unit 812 sets the distance between the drone 100a flying according to the first flight plan and the drone 100b flying according to the second flight plan at least a predetermined threshold. A first flight plan 822a and a second flight plan 822b to be kept at all times are determined and stored in the storage unit 820. Specifically, the flight plan generation unit 812 changes the flight speed of the drone 100a flying according to the draft 821a of the first flight plan and the flight speed of the drone 100b flying according to the draft 821b of the second flight plan. The first flight plan 822a and the second flight plan 822b are determined by changing the other accordingly.

Next, the operation of this embodiment will be described. Prior to causing the

drones

100a and 100b to fly, the agriculturalist 402 operates the user terminal 401 to generate a first flight plan for the drone 100a and a second flight plan for the drone 100b. Instruct the server 405. When the communication processing unit 811 receives this instruction on the server 405, the flight plan generation unit 812 executes a process for generating the flight plan.

FIG. 11 is a flowchart of the process for generating this flight plan. First, the flight plan generation unit 812 generates a first flight plan draft 821a and a second flight plan draft 821b based on the map data 823 (step S1).

FIG. 12 is a plan view illustrating the flight route RT which is a part of the flight route of the drone shown by these drafts 821a and 821b. The flight route RTs of the

drones

100a and 100b differ only in the flight altitude, and their plan views are the same.

As shown in FIG. 12, the flight route RT includes a turn-back section RTc in which the

drones

100a and 100b turn 180 degrees. In the flight route RT, the position P3 is the start position of the turn-back section RTc, and the position P4 is the end position of the turn-back section RTc. The section from the position P1 to the position P2 away from the turn-back section RTc and the section from the position P5 to the position P6 are constant velocity sections in which the

drones

100a and 100b fly at a constant speed V1. Further, the section from the position P2 to the position P3 is a deceleration section in which the speeds of the

drones

100a and 100b are decelerated from the speed V1 to a lower speed V2 in preparation for the approach to the turn-back section RTc. Then, in the turn-back section RTc, the

drones

100a and 100b fly at the lowest speed V2 in order to ensure flight stability. The section from the end position P4 to the position P5 of the turn-back section RTc is an acceleration section that accelerates the speeds of the

drones

100a and 100b from the speed V2 to the speed V1 in preparation for entering the constant velocity section from the position P5 to the position P6. be.

FIG. 13 is a diagram showing the time change of the speed VFa of the drone 100a in the draft 821a and the time change of the speed VFb of the drone 100b in the draft 821b. In FIG. 13, the horizontal axis is the time relative to the time when the drone 100a passes the position P1, and the vertical axis is the flight speed VFa of the drone 100a and the flight speed VFb of the drone 100b. In this example, the flight speed VFa in the constant velocity section (between positions P1 and P2, between positions P5 and P6) is the maximum speed V1 = 2 m / s, and the flight speed VFb in the turn-back section RTc (position P3) is the minimum speed V2 = 1 m. It is / s. In draft 821a, the drone 100b starts flying with a predetermined time delay from the drone 100a. Then, in the draft 821b, the flight speed VFb of the drone 100b is obtained by horizontally moving the flight speed VFa of the drone 100a in the horizontal axis direction for a predetermined time.

In step S2 of FIG. 11, the flight plan generation unit 812 executes a simulation of the operation when the

drones

100a and 100b fly according to the drafts 821a and 821b. FIG. 14 is a diagram showing the time change of the flight distance DFa from the position P1 of the drone 100a and the flight distance DFb from the position P1 of the drone 100b obtained by this simulation. In FIG. 14, the horizontal axis is the time relative to the time when the drone 100a passes the position P1, and the vertical axis is the flight distance DFa of the drone 100a and the flight distance DFb of the drone 100b.

According to FIG. 13 above, the preceding drone 100a passes the position P2 at 15 minutes and starts decelerating, but at this time, the succeeding drone 100b is flying at a constant speed. Therefore, as shown in FIG. 14, after the time of 15 minutes, the flight distance DFb of the subsequent drone 100b approaches the flight distance DFa of the preceding drone 100a. This tendency continues until the subsequent drone 100b arrives at the start position P3 of the turnaround section RTc. When both the preceding drone 100a and the succeeding drone 100b are within the turnaround section RTc, the difference in flight distance between the two remains constant. Then, at around time 65 minutes, when the preceding drone 100a passes the end position P4 of the turn-back section RTc and starts accelerating, the flight distance DFa of the drone 100a is from the flight distance DFb of the drone 100b, as shown in FIG. Gradually move away. This tendency continues until the time when the subsequent drone 100b arrives at the position P5, which is the end position of the acceleration section of the turnaround section RTc (time is about 77 minutes in the example of FIG. 14).

FIG. 15 is a diagram showing the difference between the flight distances DFa and DFb in FIG. 14, that is, the time change of the distance DD between the

drones

100a and 100b. In FIG. 14, the horizontal axis is the time relative to the time when the drone 100a passes the position P1, and the vertical axis is the distance DD between the

drones

100a and 100b. In this example, the distance DD between the

drones

100a and 100b is shortened during the period from when the preceding drone 100a passes the position P2 where the deceleration starts to when the subsequent drone 100b arrives at the position P5 where the acceleration ends. In the example of FIG. 15, the distance DD, which was 5 m at the longest, is shortened to 2.5 m at the shortest.

In such a case, the risk of collision between the

drones

100a and 100b increases, and for example, the drone 100b may spray the drug on the water surface where the floating plants on the water surface have not been sufficiently retreated.

Further, when following the drafts 821a and 821b, the preceding drone 100a passes through the turn-back section RTc from the position P3 to the position P4, enters the straight section from the position P4 to the position P5, and at the timing of increasing the speed, the subsequent drone 100b is still in progress. Is within the turnaround section RTc and cannot increase the speed. Therefore, the distance between the

drones

100a and 100b becomes long. In this case, there is no danger of collision, but when the succeeding drone 100b, which arrives after a lapse of time more than usual after the preceding drone 100a leaves, tries to spray the drug, the floating plants cover the water surface again. , The sprayed chemicals may be placed on the floating plants and may not be sufficiently soluble in water.

Therefore, in the present embodiment, the flight plan generation unit 812 modifies the flight speeds of the

drones

100a and 100b in the drafts 821a and 821b in step S3 of FIG. 11, and modifies the flight speeds of the first flight plan 822a for the drone 100a. And generate a second flight plan 822b for the drone 100b. Specifically, the flight plan generation unit 812 has the flight speed of the first flight plan 822a and the flight speed of the second flight plan 822b so as to match the slower speed at each timing of the drafts 821a and 821b. To fix. That is, during the period in which the drone 100a decelerates due to a change of direction, the drone 100b also decelerates in the same manner as the drone 100a, and even if the drone 100a enters a straight section, if the drone 100b decelerates due to a change of direction. , Rewrite the flight plan so that the drone 100a also flies at the decelerating speed.

FIG. 16 is a diagram illustrating the outline of the first flight plan 822a and the second flight plan 822b generated in step S3. FIG. 16 shows the same flight route RT and positions P1 to P6 as in FIG. 12 above.

In the first flight plan 822a, the deceleration of the drone 100a is started at the position P2a which is the same as the position P2 of the draft 821a. When the drone 100a passes the position P2a, the drone 100b passes the position P2b in front of the position P2a. Therefore, in the second flight plan 822b, the deceleration of the drone 100b is started at the position P2b.

When the deceleration of the drone 100a is started at the position P2a, the speed of the drone 100a reaches the minimum speed V2 at the position P3a which is the same as the position P3 of the draft 821a. Therefore, in the first flight plan 822a, the flight of the drone 100a at the minimum speed V2 is started at the position P3a. At this time, the drone 100b has passed the position P3b in front of the position P3a, and the speed of the drone 100b at this time has also reached the minimum speed V2. Therefore, in the second flight plan 822b, the drone 100b is made to start the constant velocity flight at the speed V2 at the position P3b.

When the flight of the drone 100a at the minimum speed V2 is started at the position P3a, when the drone 100a arrives at the position P4 of the draft 821a, the drone 100b is still at the position P4b'in the turn-back section RTc. When the drone 100a accelerates at this timing, the distance between the

drones

100a and 100b increases. Therefore, in the first flight plan 822a, the acceleration of the drone 100a is started at the position P4a of the drone 100a when the drone 100b arrives at the position P4b which is the same as the position P4. Further, in the second flight plan 822b, the acceleration of the drone 100b is started at the position P4b.

The drone 100b that started accelerating at the same position P4b as the position P4 reaches the maximum speed V1 at the same position P5b as the position P5 of the draft 821b. At this time, the drone 100a is at the position P5a past the position P5b, and the speed has reached the maximum speed V1. Therefore, in the first flight plan 822a, the drone 100a is started to fly at the maximum speed V1 at the position P5a. Further, in the second flight plan 822b, the drone 100b is started to fly at the maximum speed V1 at the position P5b.

FIG. 17 is a diagram showing the time change of the speed VFa of the drone 100a in the first flight plan 822a and the time change of the speed VFb of the drone 100b in the second flight plan 822b. In FIG. 17, the horizontal axis is the time relative to the time when the drone 100a passes the position P1, and the vertical axis is the flight speed VFa of the drone 100a and the flight speed VFb of the drone 100b. According to the first flight plan 822a and the second flight plan 822b, when the drone 100a is in position P2a and the drone 100b is in position P2b, both drones start decelerating at the same time. Further, when the drone 100a is at the position P3a and the drone 100b is at the position P3b, both drones simultaneously start constant velocity flight at the minimum speed V2 = 1 m / s. Also, when the drone 100a is at position P4a and the drone 100b is at position P4b, both drones start accelerating at the same time. Further, when the drone 100a is at the position P5a and the drone 100b is at the position P5b, both drones simultaneously start constant velocity flight at the maximum speed V1 = 2 m / s.

FIG. 18 is a diagram showing time changes of the flight distance DFa from the position P1 of the drone 100a and the flight distance DFb from the position P1 of the drone 100b when flying according to the first flight plan 822a and the second flight plan 822b. be. In FIG. 18, the horizontal axis is the time relative to the time when the drone 100a passes the position P1, and the vertical axis is the flight distance DFa of the drone 100a and the flight distance DFb of the drone 100b.

As shown in Fig. 17 above, the preceding drone 100a and the succeeding drone 100b always change their speeds at the same timing, so they always fly at the same speed. Therefore, as shown in FIG. 18, the flight distance DFb of the subsequent drone 100b is a translation of the flight distance of the preceding drone 100a in the vertical direction.

FIG. 19 is a diagram showing the difference between the flight distances DFa and DFb in FIG. 18, that is, the time change of the distance DD between the

drones

100a and 100b. In FIG. 19, the horizontal axis is the time relative to the time when the drone 100a passes the position P1, and the vertical axis is the distance DD between the

drones

100a and 100b. As shown in FIG. 18 above, the flight distance DFb of the succeeding drone 100b is a translation of the flight distance of the preceding drone 100a in the vertical direction. Therefore, the distance between the drones of the preceding drone 100a and the succeeding drone 100b is always maintained at a constant value (5 m in the illustrated example).

In step S4 of FIG. 11, the first flight plan 822a and the second flight plan 822b thus generated are transmitted to the

drones

100a and 100b by the communication processing unit 811. The first flight plan 822a is stored in the storage unit 720 of the drone 100a as the first flight plan 721. Similarly, the second flight plan 822b is also stored in the storage unit 720 of the drone 100b. Then, when a flight start instruction is given to the

drones

100a and 100b from the user terminal 401, the drone 100a flies according to the first flight plan, and the drone 100b flies according to the second flight plan.

As described above, according to the present embodiment, the flight plan generation unit 812, which is the determining means, flies according to the first flight plan, the first unmanned aircraft, the drone 100a, and the second flight plan. The second unmanned aircraft, the drone 100b, determines the first flight plan and the second flight plan so as to always maintain a distance equal to or greater than a predetermined threshold, thus reducing the risk of collision between the

drones

100a and 100b. can do.

<Second Embodiment>
In the first embodiment, in order to reduce the risk of collision between drones, the first flight plan 822a and the second flight plan 822a and the second flight plan so that the distance between the drones of the preceding drone 100a and the succeeding drone 100b becomes equal to or larger than the threshold value. The flight plan 822b was decided. This embodiment is suitable when the preceding drone 100a knocks down the stock by downwashing and the succeeding drone 100b takes a picture of the water surface where the stock is knocked down.

However, for example, when the drone 100b sprays chemicals such as pesticides and fertilizers on the water surface where the floating plants have been removed by the downwash of the drone 100a, the distance between the drones is not kept above the threshold value, but rather two drones. It is preferable that the time difference between the two passing through the same position is constant. The reason is as follows.

In the period when the two

drones

100a and 100b are flying at low speed, the time difference between the time when the preceding drone 100a passes a certain point and the time when the subsequent drone 100b arrives at that point is the period during which the preceding drone 100a is flying at high speed. It will be longer than the time difference in. For this reason, it is possible that the floating plants on the surface of the water removed by the drone 100a have returned to their original locations when the drone 100b arrives. Therefore, in the case where the preceding drone 100a can move the floating plants on the water surface, the time difference between the two drones passing through a certain point when viewed in a plan view is constant, not the distance between the

drones

100a and 100b. Is desirable.

Therefore, in the second embodiment of the present invention, the flight plan generation unit 812 reduces the risk of collision without changing the time difference between the timings at which the two drones pass the same point in a plan view. Then, the flight plan generation unit 812 in the present embodiment positions the drone 100a and the drone 100b flying according to the second flight plan in the three-dimensional space according to the change in the flight speed of the drone 100a flying according to the first flight plan. Determine the first and second flight plans so that the relationship changes. Specifically, it is as follows.

In the first and second flight plans of the present embodiment, the flight routes of the

drones

100a and 100b viewed from above the field 403 and the flight modes along the flight routes (specifically, acceleration flight, deceleration flight, and flight mode). The starting position of the constant velocity flight) is as shown in FIG. 12 above (that is, the draft of the first and second flight plans of the first embodiment). In the present embodiment, in the plan view, the start position of the acceleration flight, the deceleration flight, and the constant velocity flight in the direction along the horizontal plane is set so as not to change the time difference of the timing when the two drones pass the same point. Reduce the risk of collision between two drones without changing from the draft.

FIG. 20 is a diagram showing time changes of the flight altitude Ha of the drone 100a and the flight altitude Hb of the drone 100b in the first and second flight plans generated by the flight plan generation unit 812 in the present embodiment. In FIG. 20, the horizontal axis is the time relative to the time when the drone 100a starts flying, and the vertical axis is the flight altitude Ha of the drone 100a and the flight altitude Hb of the drone 100b. In this example, when the distance between the two vehicles starts to shrink when viewed in a plan view, specifically, when the drone 100a reaches the position P2 in FIG. 12 above, the drone 100b makes the flight altitude Hb from 30 cm above the crop. Start raising to 60 cm. Then, during the period when both of them fly at a low speed of 1 m / s, the drone 100b flies over 60 cm of the crop. Then, when the distance between the two drones begins to widen when viewed in a plan view, specifically, when the drone 100a reaches the position P4 in FIG. 12 above, the drone 100b raises the flight altitude Hb from 60 cm to 30 cm above the crop. Start lowering to. Then, during the period when both of them fly at high speed of 2 m / s, the drone 100b flies over 30 cm of the crop.

As described above, in the present embodiment, the flight altitude Hb of the drone 100b is set higher than the flight altitude of the drone 100a during the low speed period in which the

drones

100a and 100b fly at a low speed and the distance between the drones in a plan view becomes short. The risk of collision is reduced. Here, in the low speed period, the distance between the drones in the plan view becomes shorter, but the time difference in the timing when the two drones pass the same point in the plan view is the period in which the two drones are flying at high speed. does not change. Therefore, after the drone 100a has repelled the floating plants at a certain point by downwashing, the drone 100b is at the same point with an appropriate time difference so that the drug sprayed by the drone 100b reaches the exposed water surface. Can be reached.

<Third Embodiment>
FIG. 21 is a diagram illustrating flight routes indicated by the first and second flight plans generated by the flight plan generation unit 812, which is a determination means in the third embodiment of the present invention.

FIG. 21 shows the flight route RTa of the drone 100a and the flight route RTb of the drone 100b. In the present embodiment, the drone 100a flies along the flight route RTa and knocks down the rice stock planted in the field 403 by downwash, and the drone 100b flies along the flight route RTb and is knocked down by the drone 100a. The source of the rice is photographed from the left side of the drone 100a. Therefore, the drone 100b flies so as to be located on the left side of the drone 100a in a plane orthogonal to the flight route RTa at the position of the drone 100a on the flight route RTa. Further, in order to reduce the risk of collision, the drone 100b always maintains a position separated by a predetermined distance on the left side of the drone 100a. In this way, the

drones

100a and 100b fly side by side while keeping a constant distance in the direction along the plane orthogonal to the flight route by flying along the flight routes RTa and RTb.

As shown in FIG. 21, the flight route RTa has a plurality of curved sections and a plurality of straight sections. Therefore, the flight route RTb flying on the left side of the flight route RTa also has a plurality of curved sections and a plurality of straight sections similar to the flight route RTa. In order to ensure flight stability, the

drones

100a and 100b decelerate in preparation for entering a curved section, accelerate after passing through the curved section, and fly at a constant speed in a straight section. In this way, the

drones

100a and 100b change the flight mode (acceleration flight, deceleration flight, constant velocity flight) along the respective flight routes RTa and RTb.

FIG. 21 illustrates a position pai (i = 1 to 18) through which the drone 100a passes on the flight route RTa and a position pbi (i = 1 to 18) through which the drone 100b passes on the flight route RTb. There is. In the present embodiment, the position pbi (i = 1 to 18) is a position separated by a predetermined distance on the left side along the plane orthogonal to the flight route RTa at the position pai (i = 1 to 18) on the flight route RTa. It has become. Then, in the present embodiment, the drone 100b passes through the position Pbi (i = 1 to 18) at the same time as the time when the drone 100a passes through the positions Pai (i = 1 to 18).

When both the

drones

100a and 100b fly in a straight section, if the flight speeds of the drone 100a and the drone 100b are the same, the

drones

100a and 100b will have corresponding positions pai and pbi on the straight section in which they fly. It will pass at the same time. However, when both the

drones

100a and 100b fly in a curved section, the radius of curvature of each section is different, so that the path lengths of both sections differ. Therefore, it is necessary to adjust the flight speed of the drone flying in the section with a long route length and the flight speed of the drone flying in the section with a short route length.

Therefore, in the example shown in FIG. 21, in order to make the

drones

100a and 100b arrive at the position pa5 and the position pb5 at the same time, the flight speed of the drone 100a in the section from the position pa4 to the position pa5 is set to the position pb4 to the position pb5. It is slower than the flight speed of the drone 100b in the section. Further, in order to make the

drones

100a and 100b arrive at the positions pa7 and the position pb7 at the same time, the flight speed of the drone 100a in the section from the position pa6 to the position pa7 is set to the flight speed of the drone 100b in the section from the position pb6 to the position pb7. Is slower than.

Further, in the example shown in FIG. 21, the drone 100b changes its attitude by 90 degrees at the position pb12 = pb13 while hovering while the drone 100a flies in the section from the position pa12 to the position pa13. Further, while the drone 100a flies in the section from the position pa14 to the position pa15, the drone 100b changes its attitude by 90 degrees at the position pb14 = pb15 and then hovering.

The above are the first and second flight plans generated by the flight plan generation unit 812, which is the determination means of the present embodiment. According to the present embodiment, the drone 100b can photograph the root of the rice planted by the drone 100a from the left side of the drone 100a while always avoiding the collision with the drone 100a.

[Modification example]
The following modifications can be considered in the above embodiment.

(1) The number of unmanned aerial vehicles accompanying the first unmanned aerial vehicle is not limited to one. That is, three or more unmanned aerial vehicles may form a formation and fly according to one flight route. For example, the first unmanned aerial vehicle causes downwash, the second unmanned aerial vehicle that follows sprays the drug, and the third unmanned aerial vehicle that flies alongside the second unmanned aerial vehicle shoots the stock. The configuration may be adopted. In the case of this example, for example, the flight plan generator 812 (determining means) of the server 405 uses a camera mounted on the third unmanned aerial vehicle to capture an image of the drug that has reached the surface of the water after being sprayed on the second unmanned aerial vehicle. The second flight plan and the third flight plan are decided so as to maintain the positional relationship that can be photographed. According to the flight control system according to this example, the agricultural worker or the like can confirm whether or not the drug has reached the water surface by the image taken by the camera mounted on the third unmanned aerial vehicle.

(2) In the first embodiment, the first unmanned aerial vehicle and the second unmanned aerial vehicle fly while keeping the positional relationship in the three-dimensional space always constant. However, the positional relationship between the first unmanned aerial vehicle and the second unmanned aerial vehicle does not have to be constant at all times.

For example, as the preceding unmanned aerial vehicle decelerates, the subsequent second unmanned aerial vehicle may fly so as to change its position in three-dimensional space with the first unmanned aerial vehicle. In this case, for example, as in the second embodiment, during the period when the first unmanned aerial vehicle decelerates, the second unmanned aerial vehicle shifts the flight route upward with respect to the flight route of the first unmanned aerial vehicle, and the right side. Alternatively, a second flight plan may be determined to shift the flight route to the left.

(3) In the first embodiment, the distance between the first unmanned aerial vehicle and the second unmanned aerial vehicle along the flight route is always kept constant. Their distance does not have to be constant at all times.

For example, the first and second flight plans are such that the faster the flight speed of the first unmanned aerial vehicle or the second unmanned aerial vehicle, the greater the distance between the first unmanned aerial vehicle and the second unmanned aerial vehicle. It may be decided. In this case, even if one unmanned aerial vehicle slows down for some reason while flying at high speed, a sufficient distance is maintained, so that even if the other unmanned aerial vehicle slows down late, the possibility of avoiding a collision increases. ..

(4) In each of the above embodiments, the decision-making means for determining the flight plan is arranged on the server 405. However, the decision-making means may be placed anywhere as long as the unmanned aerial vehicle can obtain the flight plan determined by the decision-making means. For example, the determination means may be arranged at any of a base station, a user terminal for the user to remotely control the unmanned aerial vehicle, and any unmanned aerial vehicle (control device of the master unmanned aerial vehicle).

(5) The first and second unmanned aircraft were delayed during flight according to the original first and second flight plans due to some reason (for example, temporary deviation from the flight route due to the wind). ), If the flight deviates from the flight plan, the determining means may redetermine the first and second flight plans. Therefore, for example, the server 405 that functions as a determination means continuously acquires the position information of the first and second unmanned aerial vehicles, and continuously determines whether or not the flight is performed according to the flight plan. To do. Then, when it is determined that the flight deviates from the flight plan, a new flight plan is promptly determined, and the determined new flight plan is transmitted to the first and second unmanned aerial vehicles. For example, if the preceding first unmanned aerial vehicle is delayed, the following second unmanned aerial vehicle temporarily approaches the first unmanned aerial vehicle, causing the second unmanned aerial vehicle to temporarily slow down, and in some cases temporarily. The second flight plan is determined so that the aircraft will fly at the same speed as the first unmanned aerial vehicle after the distance to the first unmanned aerial vehicle returns to a predetermined distance after the retreat.

401 ... user terminal, 402 ... farmer, 403 ... field, 404 ... base station, 405 ... server, 406 ... departure / arrival point, 100a, 100b ... drone, 101 ... rotary wing, 501 ... … Data processing device, 503, 519 …… WiFi slave unit, 504 …… GPS module, 505 …… 6-axis gyro sensor, 506 …… magnetic sensor, 507 …… pressure sensor, 508 …… laser sensor, 509 …… sonar 510 ... Flow sensor, 511 ... Liquid drain sensor, 512a ... Visible light camera, 512b ... First spectrum camera, 512c ... Second spectrum camera, 513 ... Obstacle detection camera, 514 ... Switch, 515 ... Obstacle contact sensor, 516 ... Cover sensor, 517 ... Drug inlet sensor, 102 ... Motor, 106 ... Pump, 107 ... LED, 518 ... Buzzer, 520 ... Speaker, 521 ... Warning light, 710, 810 ... CPU, 720, 820 ... Storage unit, 711, 811 ... Communication processing unit, 712 ... Flight control unit, 721 ... First flight plan, 821a ... First flight Total pixel plan, 821b ... Second flight meter pixel plan, 822a ... First flight plan, 822b ... Second flight plan, 823 ... Map data, 812 ... Flight plan generation unit.

Claims

A first flight plan showing a flight route when a first unmanned aircraft flies over the target area and a mode of flight along the flight route, and a second unmanned aircraft fly over the target area. It is provided with a decision-making means for determining a second flight plan indicating the flight route and the mode of flight along the flight route.
The determining means is determined when the first unmanned aircraft flying according to the first flight plan and the second unmanned aircraft flying according to the second flight plan fly over the target area. A flight control system that determines the first flight plan and the second flight plan so as to maintain a distance equal to or greater than the threshold value of.
The determinant means the other as the flight speed of the first unmanned aircraft flying according to the first flight plan and the flight speed of the second unmanned aircraft flying according to the second flight plan change. The flight control system according to claim 1, wherein the first flight plan and the second flight plan are determined so as to change.
The determining means are the first unmanned aircraft and the second unmanned aircraft flying according to the second flight plan as the flight speed of the first unmanned aircraft flying according to the first flight plan changes. The flight control system according to claim 1 or 2, wherein the first flight plan and the second flight plan are determined so that the positional relationship in the three-dimensional space of the above changes.
When the first unmanned aircraft flies ahead of the second unmanned aircraft, the lower the flight speed of the first unmanned aircraft, the lower the flight speed of the first unmanned aircraft, the more the first unmanned aircraft and the first unmanned aircraft. The flight control system according to claim 3, wherein the first flight plan and the second flight plan are determined so that the altitude difference between the two unmanned aircraft is large.
The determining means is such that when the first unmanned aircraft and the second unmanned aircraft fly at different altitudes, the second unmanned aircraft flies at a higher altitude than the first unmanned aircraft. The flight control system according to claim 4, wherein the first flight plan and the second flight plan are determined.
The determining means are the first unmanned aircraft and the second unmanned aircraft flying according to the second flight plan as the flight speed of the first unmanned aircraft flying according to the first flight plan changes. The flight control system according to any one of claims 1 to 5, which determines the first flight plan and the second flight plan so that the distance of the flight is changed.
The determining means is such that the distance between the first unmanned aircraft flying according to the first flight plan and the second unmanned aircraft flying according to the second flight plan is kept constant. The flight control system according to any one of claims 1 to 5, which determines the flight plan and the second flight plan.
The determining means is the time when the first unmanned aircraft flying according to the first flight plan and the second unmanned aircraft flying according to the second flight plan pass the positions corresponding to each other on each flight route. The flight control system according to any one of claims 1 to 5, which determines the first flight plan and the second flight plan so that the difference between the two is kept constant.
A first flight plan showing a flight route when a first unmanned aircraft flies over the target area and a mode of flight along the flight route, and a second unmanned aircraft fly over the target area. It is provided with a decision-making means for determining a second flight plan indicating the flight route and the mode of flight along the flight route.
The determination means is such that the image of the stock of the crop that has been knocked down by the downdraft generated by the first unmanned aerial vehicle can be taken by the camera mounted on the second unmanned aerial vehicle. A flight control system that determines a first flight plan and the second flight plan.
A first flight plan showing a flight route when a first unmanned aircraft flies over the target area and a mode of flight along the flight route, and a second unmanned aircraft fly over the target area. It is provided with a decision-making means for determining a second flight plan indicating the flight route and the mode of flight along the flight route.
The determining means is a chemical sprayed by the second unmanned aerial vehicle on the water surface exposed by the water surface floating plants floating on the water surface of the target area due to the downdraft generated by the first unmanned aerial vehicle. A flight control system that determines the first flight plan and the second flight plan so as to maintain the positional relationship that the aircraft reaches.
It is equipped with a third unmanned aerial vehicle that accompanies the second unmanned aerial vehicle and flies.
The determining means determines a flight route when the third unmanned aerial vehicle flies over the target area and a third flight plan showing a mode of flight along the flight route.
The determination means and the second flight plan so as to maintain a positional relationship in which an image of the drug sprayed on the second unmanned aerial vehicle and reaching the water surface can be taken by a camera mounted on the third unmanned aerial vehicle. The flight control system according to claim 10, which determines the third flight plan.