Unmanned aerial vehicle and unmanned aerial vehicle control system

Abstract

Provided is a control system for controlling flight of an unmanned aerial vehicle, the control system comprising a control device that sets a geofence for the unmanned aerial vehicle, and controls the unmanned aerial vehicle to fly within the geofence. In this invention, the control device has a variable geofence mode in which the geofence is varied while the unmanned aerial vehicle is flying over a field.

Description

Unmanned aerial vehicles and unmanned aerial vehicle control systems

[0001] The present disclosure relates to unmanned aerial vehicles and control systems for unmanned aerial vehicles.

[0002] An unmanned aerial vehicle (UAV) is an aircraft that cannot carry a person due to its structure and can fly by remote control or automatic pilot. Rotary-wing unmanned aerial vehicles are unmanned aerial vehicles that obtain lift using propellers that rotate around an axis, i.e., rotors. Small unmanned aerial vehicles equipped with multiple rotors (multi-rotor UAVs) are also called "drones," "multirotors," or "multicopters," and are widely used for applications such as aerial photography, surveying, logistics, and pesticide spraying.

[0003] Patent Document 1 describes an unmanned aerial vehicle (unmanned flying object) that changes its flight position in conjunction with the operation of agricultural machinery.

[0004] Japanese Patent Application Laid-Open No. 2022-104737

[0005] Further improvements in the control systems that control the flight of unmanned aerial vehicles are required.

[0006] The present disclosure provides a control system capable of efficiently controlling the flight of an unmanned aerial vehicle, and an unmanned aerial vehicle equipped with such a control system.

[0007] In an exemplary and non-limiting embodiment, the control system of the present disclosure is a control system that controls the flight of an unmanned aerial vehicle, and includes a control device that sets a geofence for the unmanned aerial vehicle and controls the unmanned aerial vehicle to fly within the geofence, and the control device has a variable geofence mode that varies the geofence while the unmanned aerial vehicle is flying over a field.

[0008] According to an embodiment of the present disclosure, there is provided a control system that controls an unmanned aerial vehicle so that it can fly efficiently, and an unmanned aerial vehicle equipped with such a control system.

[0009] 1 is a block diagram schematically showing several examples of a rotary drive device that rotates rotors in an unmanned aerial vehicle having multiple rotors. FIG. 2 is a plan view schematically showing one basic configuration example of an unmanned aerial vehicle having multiple rotors. FIG. 3 is a side view schematically showing one basic configuration example of an unmanned aerial vehicle having multiple rotors. FIG. 4 is a plan view schematically showing another basic configuration example of an unmanned aerial vehicle having multiple rotors. FIG. 5 is a block diagram showing an example basic configuration of a battery-powered multicopter. FIG. 6 is a block diagram showing an example basic configuration of a series hybrid drive multicopter. FIG. 7 is a block diagram showing an example basic configuration of a parallel hybrid drive multicopter. FIG. 8 is a diagram schematically showing an example environment in which a multicopter flies. FIG. 9 is a diagram schematically showing an example environment in which a multicopter flies and an example geofence for the multicopter. FIG. 10 is a flowchart showing an example operation of a control device in this embodiment. FIG. 11 is a flowchart showing an example operation of a control device in this embodiment. FIG. 12 is a diagram showing an example GUI displayed on a display device. FIG. 13 is a diagram showing an example GUI displayed on a display device. FIG. 14 is a block diagram showing an example hardware configuration of a control device in this embodiment. FIG. 1 is a schematic diagram showing an example in which a multicopter, an agricultural machine, a server, and a terminal device are connected via a communication network.

[0010] An unmanned aerial vehicle with multiple rotors includes a rotary drive unit that rotates the rotors (hereinafter sometimes referred to as "propellers"). Hereinafter, such an unmanned aerial vehicle will be referred to as a "multicopters."

[0011] There are various configurations of the rotary drive device provided in a multicopter. Fig. 1A is a block diagram schematically illustrating four examples of the rotary drive device 3 in the present disclosure.

[0012] The first rotation drive device 3A shown in FIG. 1A has a plurality of electric motors (hereinafter referred to as "motors") 14 that rotate a plurality of rotors 2, and a battery 52 that stores power to be supplied to each motor 14. The battery 52 is, for example, a secondary battery such as a polymer lithium-ion battery. Each rotor 2 is connected to the output shaft of the corresponding motor 14 and rotated by the motor 14. In order to increase the payload and / or flight time, it is necessary to increase the power storage capacity of the battery 52. ​​The power storage capacity of the battery 52 can be increased by increasing the size of the battery 52, but increasing the size of the battery 52 results in an increase in weight.

[0013] 1A includes a power transmission system 23 mechanically connected to the rotor 2 and an internal combustion engine 7a that provides driving force (torque) to the power transmission system 23. The power transmission system 23 includes mechanical components such as gears or belts, and transmits torque from the output shaft of the internal combustion engine 7a to the rotor 2. The internal combustion engine 7a can efficiently generate mechanical energy by burning fuel. Examples of the internal combustion engine 7a include a gasoline engine, a diesel engine, and a hydrogen engine.

[0014] The third rotary drive device 3C shown in FIG. 1A includes multiple motors 14, a power buffer 9 that stores power to be supplied to each motor 14, a power generator 8 such as an alternator that generates power, and an internal combustion engine 7a that provides mechanical energy for the power generator 8 to generate electricity. A typical example of the power buffer 9 is a battery such as a secondary battery, but it may also be a capacitor. In the third rotary drive device 3C, even if the power buffer 9 does not have a large storage capacity, the power generator 8 generates power using the driving force (mechanical energy) of the internal combustion engine 7a, thereby enabling an increase in payload and / or flight time. This type of drive is called a "series hybrid drive." The power generator 8 and internal combustion engine 7a in the series hybrid drive are called a "range extender" because they extend the flight distance of the multicopter.

[0015] 1A includes a plurality of motors 14, a power buffer 9 that stores power to be supplied to each motor 14, a power generator 8 such as an alternator that generates power, an internal combustion engine 7a that provides driving force for generating power to the power generator 8, and a power transmission system 23 that transmits the driving force generated by the internal combustion engine 7a to a rotor 2 to rotate the rotor 2. At least one rotor 2 of the plurality of rotors 2 is rotated by the internal combustion engine 7a, and the other rotors 2 are rotated by the motor 14. In the fourth rotary drive device 3D, the mechanical energy generated by the internal combustion engine 7a can also be used to rotate the rotor 2 without being converted into electric power, thereby improving energy utilization efficiency. This type of drive is called a "parallel hybrid drive."

[0016] Fig. 1B is a plan view schematically illustrating one basic configuration example of multicopter 10. The configuration example of Fig. 1B includes the first rotational drive device 3A shown in Fig. 1A as the rotational drive device 3. That is, the rotational drive device 3 (3A) in this example includes a motor 14 and a battery 52. ​​Fig. 1C is a side view schematically illustrating multicopter 10.

[0017] 1B and 1C includes a plurality of rotors 2, an airframe 4, and an airframe frame 5 that supports the rotors 2 and the airframe 4. The airframe frame 5 supports the airframe 4 at its center and rotatably supports the plurality of rotors 2 with a plurality of arms 5A extending outward from the center. A motor 14 that rotates the rotors 2 is provided near the tip of each arm 5A. The airframe 4 and the airframe frame 5 are sometimes collectively referred to as the "airframe 11."

[0018] 1B, the multicopter 10 is a quad-type multicopter (quadcopter) having four rotors 2. The rotors 2 located on one diagonal line rotate in the same direction (clockwise or counterclockwise), while the rotors 2 located on different diagonal lines rotate in opposite directions.

[0019] The main body 4 includes a control device 4a that controls the operation of devices and components mounted on the multicopter 10, a group of sensors 4b connected to the control device 4a, a communication device 4c connected to the control device 4a, and a battery 52.

[0020] The control device 4 a may include, for example, a flight control device such as a flight controller and a host computer (companion computer). The companion computer can perform advanced arithmetic processing such as image processing, obstacle detection, and obstacle avoidance based on the sensor data acquired by the sensor group 4 b.

[0021] The sensor group 4b may include an acceleration sensor, an angular velocity sensor, a geomagnetic sensor, a barometric pressure sensor, an altitude sensor, a temperature sensor, a flow rate sensor, an imaging device, a laser sensor, an ultrasonic sensor, an obstacle contact sensor, and a Global Navigation Satellite System (GNSS) receiver. The acceleration sensor and the angular velocity sensor may be mounted on the airframe main body 4 as components of an IMU (Inertial Measurement Unit). Examples of the laser sensor may include, for example, a laser range finder used to measure the distance to the ground, and a two-dimensional or three-dimensional light detection and ranging (LiDAR).

[0022] The communication device 4c may include a wireless communication module for transmitting and receiving signals via an antenna to a transmitter or ground station (Ground Control Station (GCS)) on the ground, a mobile communication module using a cellular communication network, etc. The communication device 4c may receive signals such as control commands transmitted from the ground and transmit sensor data such as image data acquired by the sensor group 4b as telemetry information. The communication device 4c may have a function for communicating between multicopters and a satellite communication function. The control device 4a can be connected to a computer on the cloud via the communication device 4c. Some or all of the functions of the companion computer may be performed by the computer on the cloud.

[0023] The battery 52 is a secondary battery that can store power by charging and supply power to the motors 14 by discharging. The battery 52 and the multiple motors 14 operate to rotate the multiple rotors 2, generating a desired thrust. Each of the multiple rotors 2 typically has multiple blades with a fixed pitch angle, generating thrust through rotation. The pitch angle may be variable. The multiple rotors 2 do not all need to have the same diameter (propeller diameter); one or more rotors 2 may have a larger diameter than the other rotors 2. The thrust (static thrust) generated by the rotating rotors 2 is generally proportional to the cube of the rotor 2 diameter. Therefore, when rotors 2 with different diameters are included, the rotor 2 with the larger diameter may be referred to as the "main rotor," and the rotor 2 with the smaller diameter may be referred to as the "sub-rotor." Regardless of the diameter, the configuration of the rotary drive device 3 may include rotors 2 with a relatively larger thrust and rotors 2 with a relatively smaller thrust. In this case, the rotor 2 capable of generating a relatively large thrust may be referred to as the "main rotor," and the rotor 2 capable of generating a relatively small thrust may be referred to as the "sub-rotor." For example, the rotor 2 capable of generating a relatively large thrust per rotation may be referred to as the "main rotor," and the rotor 2 capable of generating a relatively small thrust per rotation may be referred to as the "sub-rotor." In one example, the main rotor may be disposed more inward than the sub-rotors. In other words, each rotor 2 may be disposed so that the distance from the center of the aircraft to the rotation axis of each main rotor is shorter than the distance from the center of the aircraft to the rotation axis of each sub-rotor.

[0024] In this example, the rotary drive device 3 includes a plurality of motors 14. As mentioned above, the rotary drive device 3 may include an internal combustion engine 7a.

[0025] FIG. 1D is a plan view schematically illustrating an example of the basic configuration of a multicopter 10 including a second rotational drive device 3B as the rotational drive device 3. In the example shown in FIG. 1D , an internal combustion engine 7a is supported by the airframe main body 4. In this example, the driving force generated by the internal combustion engine 7a is transmitted to multiple rotors 2 via multiple power transmission systems 23, causing each rotor 2 to rotate. The control device 4a can change the rotational speed of each rotor 2 by controlling each power transmission system 23. The rotational drive device 3B may include a mechanism for changing the pitch angle of each blade of the multiple rotors 2. In this case, the control device 4a may adjust the lift generated by each rotor 2 by controlling the mechanism to change the pitch angle of the blades.

[0026] In a "parallel hybrid drive" in which some of the multiple rotors 2 are rotated by the internal combustion engine 7a and the other rotors 2 are rotated by the motor 14, the internal combustion engine 7a and the battery 52 are supported on the aircraft body 4. At least one rotor 2 of the multiple rotors 2 is connected to the internal combustion engine 7a via the power transmission system 23, and the other rotors 2 are connected to the motor 14.

[0027] In such a parallel hybrid drive, the diameter of one or more rotors 2 rotated by the internal combustion engine 7a may be larger than the diameter of the other rotors 2 rotated by the motor 14. In other words, the internal combustion engine 7a may be used to rotate the main rotor, and the motor 14 may be used to rotate the sub-rotor. In such a case, the main rotor is primarily used to generate thrust, and the sub-rotor is used to generate thrust and for attitude control. The main rotor may also be called a "booster rotor," and the sub-rotor may also be called an "attitude control rotor."

[0028] In the case of a parallel hybrid drive, the internal combustion engine is used for both thrust generation and power generation. By selectively transmitting the driving force (torque) generated by the internal combustion engine to one or both of the rotor and the power generator, it is possible to achieve a good balance between thrust generation and power generation.

[0029] Equipping a multicopter with an internal combustion engine and using it to generate thrust and / or electricity contributes to increased payload and flight time. It is desirable to control the attitude of a multicopter by rotating the propellers with a motor, which has better response characteristics than an internal combustion engine. Therefore, in applications requiring precise control of the multicopter's attitude, it is desirable to employ a parallel hybrid drive or series hybrid drive to increase the payload and flight time. If the rotary drive device 3 is equipped with a mechanism for changing the pitch angle of each blade of the multiple rotors 2, the attitude can also be adjusted by changing the pitch angle of each blade.

[0030] Increased payload and flight time may further expand the applications of multicopters. For example, in the agricultural field, multicopters are currently being used for spraying pesticides or monitoring crop growth conditions. However, by connecting various ground implements (hereinafter, sometimes simply referred to as "implements") to a multicopter, various agricultural tasks can be performed from the air. Agricultural implements are sometimes called "implements." Examples of implements include sprayers that spray pesticides on crops, mowers, seeders, spreaders, rakes, balers, harvesters, plows, harrows, or rotary tillers. Work vehicles such as tractors are not included in the "implements" of this disclosure.

[0031] In the example shown in FIG. 1C , a work implement 200 is coupled to the multicopter 10. The work implement 200 can spray, for example, pesticides or fertilizers on a field or crops within the field. Increasing the payload and flight time allows for a larger and / or more versatile work implement 200. For example, by changing the work implement 200 coupled to the multicopter 10, a variety of ground tasks (agricultural operations) can be performed, including liquid and granular application of pesticides, fertilization, thinning, weeding, transplanting, direct seeding, and harvesting. The work implement 200 may be equipped with a mechanism such as a robotic hand. In this case, a single work implement 200 can perform a variety of ground tasks. If the work implement 200 has a sufficient space to accommodate materials, the work implement 200 can also be used to transport agricultural materials or harvested products over a wide area. The work implement 200 can be coupled to the multicopter 10 in a variety of ways. The multicopter 10 may suspend and tow the work machine 200 by a cable. The work machine 200 towed by the multicopter 10 can also perform ground work while being towed while the multicopter 10 is flying or hovering. The work machine 200 during work may be in the air or on the ground.

[0032] 1C , the multicopter 10 includes a power supply device 76. The power supply device 76 is a device that supplies power to the work machine 200 from a drive energy source, such as the battery 52 or the power generation device 8, included in the multicopter 10. Various functions of the work machine 200 can be performed using this power. The work machine 200 includes actuators such as motors that operate using power obtained from the power supply device 76 of the multicopter 10. The work machine 200 preferably includes a battery that stores power.

[0033] FIG. 2A is a block diagram showing an example of the basic configuration of a battery-powered multicopter 10.

[0034] The battery-powered multicopter 10 includes multiple rotors 12, multiple motors 14 for rotating the rotors 12, multiple electric speed controllers (ESCs) 16 each having a motor drive circuit for driving the motors 14, a battery 52 for supplying power to the corresponding motors 14 via each ESC 16, a control device 4a for controlling the ESCs 16 to control attitude and flight, a sensor group 4b, a communication device 4c, and a power supply device 76 electrically connected to the battery 52. ​​For simplicity, FIG. 2A shows the rotors 12, motors 14, and ESCs 16 as a single block, but the number of rotors 12, motors 14, and ESCs 16 is actually multiple. This also applies to FIGS. 2B and 2C. The ESC 16 may be included in the control device 4a.

[0035] The control device 4a can receive control commands wirelessly, for example, from a ground station 6 located on the ground via the communication device 4c. The number of ground stations 6 is not limited to one and may be distributed across multiple locations. The communication device 4c can also receive control commands wirelessly from a control device operated by a pilot on the ground. The control device 4a may have the function of automatically or autonomously performing takeoff, flight, obstacle avoidance, and landing operations based on sensor data obtained from the sensor group 4b. The control device 4a may be configured to communicate with the work machine 200 connected to the power supply device 76 and acquire a signal indicating the status of the work machine 200 from the work machine 200. The control device 4a may also provide the work machine 200 with a signal that controls the operation of the work machine 200. Furthermore, the work machine 200 may generate a signal instructing the operation of the multicopter 10 and transmit it to the control device 4a. Such communication between the control device 4a and the work machine 200 can be performed via wired or wireless communication.

[0036] FIG. 2B is a block diagram showing an example of the basic configuration of a series hybrid drive multicopter 10. Similar to the battery-powered multicopter 10, the series hybrid drive multicopter 10 includes multiple rotors 12, multiple motors 14, multiple ESCs 16, a control device 4a, a sensor group 4b, and a communication device 4c. The illustrated series hybrid drive multicopter 10 further includes an internal combustion engine 7a, a fuel tank 7b for storing fuel for the internal combustion engine 7a, a power generation device 8 driven by the internal combustion engine 7a to generate electric power, a power buffer 9 for temporarily storing the electric power generated by the power generation device 8, and a power supply device 76 electrically connected to the power buffer 9. The power buffer 9 is, for example, a battery such as a secondary battery. The electric power generated by the power generation device 8 is supplied to the motor 14 via the power buffer 9 and the ESC 16. The electric power generated by the power generation device 8 may also be supplied to the work machine 200 via the power supply device 76.

[0037] FIG. 2C is a block diagram showing an example of the basic configuration of a parallel hybrid drive multicopter 10. Similar to the series hybrid drive multicopter 10, the parallel hybrid drive multicopter 10 includes multiple rotors 12, multiple motors 14 that respectively drive the multiple rotors 12, multiple ESCs 16, a control device 4a, a sensor group 4b, a communication device 4c, an internal combustion engine 7a, a fuel tank 7b, a power generator 8, a power buffer 9, and a power supply device 76. The parallel hybrid drive multicopter 10 further includes a drive train 27 that transmits the driving force of the internal combustion engine 7a, and a rotor 22 that rotates by receiving the driving force of the internal combustion engine 7a from the drive train 27. One of the rotor 12 and the rotor 22 may be referred to as the “first rotor” and the other as the “second rotor” to distinguish them from each other. The number of rotors 22 connected to the drive train 27 and rotating may be one or more.

[0038] In the parallel hybrid drive multicopter 10, the internal combustion engine 7a not only drives the power generation device 8 to generate electricity, but also mechanically transmits energy to the rotor 22 to rotate the rotor 22. On the other hand, in the series hybrid drive multicopter 10, all of the rotors 12 are rotated by the electric power generated by the power generation device 8. For this reason, in the series hybrid drive multicopter 10, if the power generation device 8 is, for example, a fuel cell, the internal combustion engine 7a is not an essential component.

[0039] Hereinafter, a control system and a control method for controlling the flight of an unmanned aerial vehicle (multicopter) according to an embodiment of the present disclosure will be described with reference to FIG. 3 .

[0040] FIG. 3 is a diagram schematically illustrating an example of an environment in which the multicopter 10 flies. In the example of FIG. 3 , the multicopter 10 is flying above a field F. For example, the multicopter 10 flies while performing agricultural work in the airspace above the field F. The multicopter 10 may be flying above a work area set within the field F. The multicopter 10 can perform various agricultural tasks (ground tasks), such as spraying pesticides, while flying above the field F. As shown in the example of FIG. 1C , the multicopter 10 may be flying above the field F with a work implement 200 connected (or suspended) from the airframe 11 (or the airframe main body 4). In such a case, instead of the multicopter 10 itself performing the agricultural work, the work implement 200 connected (or suspended) from the airframe 11 of the multicopter 10 can also perform the agricultural work. Even in such a case, the term "multicopter 10 performs agricultural work" is used in this specification. The multicopter 10 may fly over a field automatically, autonomously, or by remote control. The multicopter 10 can operate in both an autonomous driving mode and a manual driving mode.

[0041] In FIG. 3 , the arrowed line shown in the field F schematically indicates the flight path traveled by the multicopter 10 in autonomous driving mode. In autonomous driving mode, the multicopter 10 is controlled to fly along a predetermined target route. In autonomous driving mode, the control device 4a causes the multicopter 10 to fly along a target route based on the position of the multicopter 10 measured by the positioning device and the target route set above the field F. The target route is set in advance by, for example, a user, and the information is recorded in a storage device. The user can set the target route by operating a GUI (Graphical User Interface) including a map of the field displayed on, for example, a setting information terminal.

[0042] The control system for controlling the flight of the multicopter 10 includes a control device 4a. The control device 4a sets a geofence 72 for the multicopter 10 and controls the multicopter 10 to fly within the geofence 72. A "geofence" is a virtual geographical boundary that defines an area in which a multicopter can fly. The control device 4a has a variable geofence mode that varies the geofence 72 while the multicopter 10 is flying over the field F. In other words, the control system can vary the geofence 72 of the multicopter 10 while the multicopter 10 is flying over the field F. The control system according to an embodiment of the present disclosure can efficiently control the flight of the multicopter 10.

[0043] 4A and 4B, an example of a method for setting a geofence for the multicopter 10 will be described. 4A and 4B are diagrams that schematically show an example of an environment in which the multicopter 10 flies and an example of a geofence for the multicopter 10.

[0044] The geofences 72 (including the geofence 72i shown in FIG. 4A and the geofence 72v shown in FIG. 4B ) are configured so that, for example, even if the rotor 2 of the multicopter 10 stops due to a malfunction or other reason and the multicopter 10 falls to the ground, it will fall within the flight-permitted area 71. The flight-permitted area 71 is an area in which the multicopter 10 is permitted to fly, and includes, for example, land or a field owned by the user. By setting the geofences 72 in this manner, if the multicopter 10 falls, it is possible to prevent the multicopter 10 from falling into an area in which the multicopter 10 is not permitted to enter (e.g., land owned by another person). In the illustrated example, the flight-permitted area 71 is included in a field F1 owned by the user. In the illustrated example, the flight-permitted area 71 may be configured so as not to include an area adjacent to the field F1 in which the multicopter 10 is not permitted to fly. For example, in the illustrated example, the flight-permitted area 71 is configured so as not to include a field F2 owned by a person other than the user. The flight-permitted area 71 may be the same range as the field F1. For example, the flight-permitted area 71 may be set to include only fields owned by the user where work is planned, and not include fields where work is not planned. The flight-permitted area 71 is not limited to being set corresponding to one field F1 as shown in the figure, but may be set across multiple fields so that the multicopter 10 can fly over multiple fields.

[0045] The control device 4a varies the geofence 72 of the multicopter 10 while the multicopter 10 is flying, for example, as follows.

[0046] As shown in FIG. 4A , the control device 4a first initializes the geofence 72. The control device 4a adjusts the geofence 72 using the initially set geofence 72 as a reference value. The initially set geofence 72 or the reference value geofence 72 may be referred to as a "geofence 72i." The control device 4a sets the geofence 72 based on a range Rd of positions (positions defined by geographic coordinates) where the multicopter 10 may fall. For example, the initial setting defines the range Rd of positions where the multicopter 10 may fall as a circle C0 with a radius r0 and centered at a position P where the center of gravity of the multicopter 10 is projected onto the ground. The initially set geofence 72i defines the maximum range within which position P can move without the circle C0 protruding from the permitted flight area 71. The initially set geofence 72i is located a distance Df inward from the permitted flight area 71, where Df = r0. In the example shown in FIG. 4, a geofence 72i is initially set inside the rectangular field F1 in a shape that follows the outer edge of the field F1.

[0047] As shown in FIG. 4B , while the multicopter 10 is flying, the control device 4a predicts a range Rd (defined by geographic coordinates) of positions where the multicopter 10 may fall, and changes (shifts) the geofence 72 based on changes in the predicted range Rd. In the example shown in FIG. 4B , the control device 4a changes the initially set geofence 72i in accordance with changes in the predicted range Rd where the multicopter 10 may fall from the circle C0. The changed geofence 72 may be referred to as a "geofence 72v." For example, if a change occurs during flight in the displacement vector from the position P where the center of gravity of the multicopter 10 is projected onto the ground to the outer edge of the range Rd where the multicopter 10 may fall, the geofence 72 is shifted based on the amount of change. 4B, when wind W is blowing from the right to the left as shown by the outline arrow in the figure, the distance from the position P where the center of gravity of the multicopter 10 is projected onto the ground to the left end of the range Rd where the multicopter 10 could fall increases by d1 from the radius r0 of the circle C0. Accordingly, the left end of the geofence 72 is shifted inward by d1 to obtain geofence 72v.

[0048] While the multicopter 10 is flying, the control device 4a acquires data that may affect the range Rd of positions (positions defined by geographic coordinates) where the multicopter 10 may fall, and based on the acquired data, can predict the range Rd of positions where the multicopter 10 may fall using various methods such as a mathematical model for determining the fall position, an equation of motion that represents the falling motion of an object, a simulation for determining the fall position of an object, etc. For example, the control device 4a acquires data related to the speed of the multicopter 10, the flight direction of the multicopter 10, the flight altitude of the multicopter 10, the weight of the multicopter 10, the weight of the work implement 200 or the payload connected to the multicopter 10, the distance between the multicopter 10 and the work implement 200 or the payload connected to the multicopter 10, the position of the center of gravity of the work implement 200 or the payload connected to the multicopter 10, the wind direction, wind speed, and precipitation above the field F1, and flying objects (e.g., birds, other unmanned aerial vehicles) present above the field F1. The control device 4a acquires this information, for example, by acquiring data output from sensors (sensing devices) included in the sensor group 4b. The sensor group 4b includes, for example, a laser sensor (e.g., LiDAR) that senses the environment around the multicopter 10 and outputs sensor data. By sensing the area around the multicopter 10 with a laser sensor, information about flying objects present above the field F1 can be obtained. The multicopter 10 may have a sensor that detects wind direction and wind speed. The control device 4a may acquire weather data including wind speed, wind direction, and precipitation from an external computer via a network such as the Internet. The weight of the work implement 200 or load connected to the multicopter 10 is detected, for example, by a sensor included in the multicopter 10. Information about the distance between the work implement 200 or load and the multicopter 10 and information about the position of the center of gravity of the work implement 200 or load may be set in advance by a user and stored in a storage device, for example.

[0049] Although FIGS. 4A and 4B illustrate an example in which one multicopter 10 is flying, multiple multicopters 10 may be flying over the same field F1. In this case, the multiple multicopters 10 may use the same initially set geofence 72i, but the changed geofence 72 may be different for each multicopter 10. This is because the flight speed, flight altitude, weight, etc. of the multiple multicopters 10 may be different. Furthermore, when multiple multicopters 10 are flying over the same field, if each multicopter 10 has a sensor for detecting wind direction and wind speed, the measured wind direction and wind speed may differ depending on the position of the multicopter 10. When changing the geofence 72, the control device 4a may use the maximum wind direction and wind speed acquired by each multicopter 10, or may use the measured values ​​at the position closest to the outer edge of the current geofence 72 of each multicopter 10. If multiple sensors for measuring wind direction and speed are installed in the field F1, the measurement values ​​of the sensor closest to the current position of each multicopter 10 may be used, or the measurement values ​​of the sensor closest to the outer edge of the current geofence 72 of each multicopter 10 may be used.

[0050] In the illustrated example, the control device 4a sets a geofence 72 that is substantially rectangular, but the shape of the set geofence can be changed as appropriate depending on the shape of the permitted flight area, etc. For example, a polygonal or circular geofence may be set.

[0051] Furthermore, the geofence of the multicopter 10 set by the control device 4a may not only define the flyable area of ​​the multicopter 10 in two dimensions using geographic coordinates, but may also be a three-dimensional boundary that defines the range of flight altitude of the multicopter 10. "Geographic coordinates" refer to a position in a geographic coordinate system that expresses a position on Earth using latitude and longitude, or a projected coordinate system that projects three-dimensional coordinates on Earth onto a two-dimensional plane and expresses a position on Earth using XY coordinates. In the example described with reference to FIGS. 4A and 4B , the geofence 72 is varied by changing the range of the geographic coordinates of the geofence 72. However, this is not limited thereto. For example, the geofence 72 may be varied by changing the range of flyable altitude of the multicopter 10.

[0052] The control device 4a controls the multicopter 10 so that the multicopter 10 flies within the geofence 72. For example, in the autonomous driving mode, if a preset target route includes a portion that extends outside the changed geofence 72, the control device 4a changes the target route so that the target route stays within the geofence 72, or causes the multicopter 10 to hover and wait at a point within the geofence 72. The control device 4a may reduce the speed of the multicopter 10 when the multicopter 10 approaches the geofence 72. When the multicopter 10 is flying by remote control in the manual driving mode, for example, when the control device 4a receives a signal instructing it to move outside the geofence 72, the control device 4a may not move in accordance with the signal but may notify the user that the movement will exceed the geofence 72.

[0053] An example of the operation of the control device 4a will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the operation of the control device 4a.

[0054] After starting the variable geofence mode, in step S10, the control device 4a acquires information that may affect the location of the fall point when the multiple rotors 2 of the multicopter 10 flying within the currently set geofence 72 stop. For example, data related to information such as the speed of the multicopter 10, the flight direction of the multicopter 10, the flight altitude of the multicopter 10, the weight of the multicopter 10, the weight of the work implement 200 or payload connected to the multicopter 10, the position of the center of gravity of the work implement 200 or payload connected to the multicopter 10, the wind direction, wind speed, and amount of precipitation above the field F1, and flying objects (e.g., birds, other unmanned aerial vehicles) present above the field F1 is acquired.

[0055] In step S12, based on the information acquired in step S10, the control device 4a predicts the position of the drop point of the multicopter 10. The position of the drop point of the multicopter 10 can be predicted as a predicted drop range having a two-dimensional spread, as in the example described with reference to Figures 4A and 4B.

[0056] In step S14, the control device 4a determines whether the predicted drop point of the multicopter 10 is within the flight-permitted area 71. If the drop point of the multicopter 10 is within the flight-permitted area 71 (if "Yes"), the process returns to step S10, for example, after a predetermined time has elapsed. If the drop point of the multicopter 10 is outside the flight-permitted area 71 (if "No"), in step S16, the control device 4a moves the geofence 72 of the multicopter 10 so that the drop point is within the flight-permitted area 71. After step S16, the process returns to step S10, for example, after a predetermined time has elapsed.

[0057] The above steps S10 and S12 may be performed simultaneously.

[0058] Another example of the operation of the control device 4a will be described with reference to Fig. 6. Fig. 6 is a flowchart showing another example of the operation of the control device 4a. Detailed description of steps common to the flowchart of Fig. 5 may be omitted.

[0059] After starting the variable geofence mode, in step S20, the control device 4a acquires information that may affect the location of the landing point when multiple rotors 2 of the multicopter 10 flying within the currently set geofence 72 stop.

[0060] In step S22, the control device 4a predicts the range of positions where the multicopter 10 may fall (predicted fall range) based on the information acquired in step S20.

[0061] In step S24, the control device 4a obtains a displacement vector from the position where the center of gravity of the multicopter 10 is projected onto the ground to the outer edge of the predicted fall range, and calculates the amount of change in the displacement vector. The change in the displacement vector may be calculated from the initially set displacement vector, or may be calculated from the displacement vector calculated during the dynamic geofence mode.

[0062] In step S26, it is determined whether or not it is necessary to change the geofence 72 based on the amount of change in the displacement vector. If it is necessary to change the geofence 72 (if "Yes"), in step S28, the geofence 72 is changed based on the amount of change in the displacement vector. After step S16, for example, after a predetermined time has elapsed, the process returns to step S20. If it is not necessary to change the geofence 72 (if "No"), for example, after a predetermined time has elapsed, the process returns to step S20.

[0063] The above steps S20, S22 and S24 may be performed simultaneously.

[0064] The control system according to an embodiment of the present disclosure may further include a fixed geofence mode in addition to the flexible geofence mode. That is, the multicopter 10 may operate in both the flexible geofence mode and the fixed geofence mode. In the fixed geofence mode, the control device 4a controls the flight of the multicopter 10 by fixing the geofence of the multicopter 10 to a preset boundary while the multicopter 10 is flying over the field F. The user may manually select the flexible geofence mode or the fixed geofence mode to control the flight of the multicopter 10, or the control device 4a may select the mode. The control system may also have other selectable modes. FIG. 7 is a diagram illustrating an example of a GUI displayed on a user's display device. In this example, a GUI is displayed that allows the user to select either the "flexible geofence mode" or the "fixed geofence mode." FIG. 7 illustrates a state in which the flexible geofence mode is selected.

[0065] In the variable geofence mode, the control system according to an embodiment of the present disclosure displays a geofence on a display device used by a user. As shown in the example of FIG. 8 , the area of ​​the field F1 may be displayed together with the geofence displayed on the display device. For example, FIG. 8 is a diagram illustrating an example of a GUI displayed on the user's display device. The area of ​​the field F1 owned by the user, the geofence 72, and the current position of the multicopter 10 are displayed together. When the geofence 72 is changed, the geofence 72 displayed on the display device is also changed accordingly. As shown in notification 78a of FIG. 8 , when the geofence 72 is changed, the user may be notified that the geofence 72 has been changed. As shown in notification 78b of FIG. 8 , when the multicopter 10 approaches the geofence 72, the user may be notified that the multicopter 10 is approaching the geofence 72.

[0066] The control device 4a in the embodiment of the present disclosure can be realized by a digital computer system programmed to execute the processes described with reference to FIGS.

[0067] 9 is a block diagram showing an example of the hardware configuration of the control device 4a. The control device 4a includes a processor 34, a read-only memory (ROM) 35, a random access memory (RAM) 36, a storage device 37, and a communication I / F 38. These components are connected to each other via a bus 39.

[0068] The processor 34 is one or more semiconductor integrated circuits, and is also referred to as a central processing unit (CPU) or a microprocessor. The processor 34 sequentially executes computer programs stored in the ROM 35 to perform the above-described processing. The term "processor 34" is broadly interpreted as including a field programmable gate array (FPGA) equipped with a CPU, a graphic processor unit (GPU), an application specific integrated circuit (ASIC), or an application specific standard product (ASSP).

[0069] The ROM 35 is, for example, a writable memory (e.g., a PROM), a rewritable memory (e.g., a flash memory), or a read-only memory. The ROM 35 stores a program that controls the operation of the processor. The ROM 35 does not have to be a single recording medium, but may be a collection of multiple recording media. Some of the collection of multiple recording media may be removable memories.

[0070] The RAM 36 provides a working area for temporarily loading the programs stored in the ROM 35 at boot time. The RAM 36 does not have to be a single recording medium, but can be a collection of multiple recording media.

[0071] The communication I / F 38 is an interface for communication between the control device 4a and other electronic components or electronic control units (ECUs). For example, the communication I / F 38 can perform wired communication in accordance with various protocols. The communication I / F 38 may perform wireless communication in accordance with the Bluetooth (registered trademark) standard and / or the Wi-Fi (registered trademark) standard. Both standards include wireless communication standards using frequencies in the 2.4 GHz band.

[0072] The storage device 37 may be, for example, a semiconductor memory, a magnetic storage device, an optical storage device, or a combination thereof. The storage device 37 may store, for example, map data useful for the autonomous flight of the multicopter 10 and various sensor data acquired by the multicopter 10 during flight.

[0073] As described above, the control device 4a may include, for example, a flight control device such as a flight controller and a host computer (companion computer). The companion computer may execute the processes shown in FIGS. 5 and 6 and issue flight-related commands based on the results of those processes to the flight controller. Furthermore, some or all of the functions of the electrical components such as the control device 4a mounted on the multicopter 10 or the above-described control system may be implemented by one or more servers (computers) 500 or terminal devices (including portable and fixed types) 600 connected to the communication device 4c of the multicopter 10 via a communication network N, as shown in FIG. 10 . An agricultural machine 700 such as a tractor may be connected to such a communication network N, and communication may be performed between the multicopter 10 and the agricultural machine 700. Some of the data used in the processing of the control device 4a and control signals for the multicopter 10 may be transmitted from the agricultural machine 700 to the multicopter 10 via the communication network N.

[0074] This specification discloses the solutions described in the following items.

[0075] [Item 1] A control system for controlling the flight of an unmanned aerial vehicle, the control system having a control device that sets a geofence for the unmanned aerial vehicle and controls the unmanned aerial vehicle to fly within the geofence, the control device having a variable geofence mode that varies the geofence while the unmanned aerial vehicle is flying over a field.

[0076] [Item 2] The control system according to Item 1, wherein the control device sets the geofence inside an area above the field while the unmanned aerial vehicle is flying over the field.

[0077] [Item 3] The control system according to Item 1 or 2, wherein the control device varies the geofence in the variable geofence mode while the unmanned aerial vehicle is flying over a field with a work implement coupled to the airframe.

[0078] [Item 4] The control system according to Item 3, wherein in the variable geofence mode, the control device varies the geofence while the unmanned aerial vehicle flies over a field with a work implement coupled to the airframe and performs work on the field.

[0079] [Item 5] The control system according to Item 4, wherein the work includes agricultural work.

[0080] [Item 6] The control system described in any one of items 1 to 5, further comprising a sensing device that senses the environment surrounding the unmanned aerial vehicle and outputs sensor data, wherein the control device varies the geofence based on the sensor data in the variable geofence mode.

[0081] [Item 7] The control system according to item 6, wherein the sensor data includes data relating to at least one of a wind speed in the surrounding environment, a precipitation amount in the surrounding environment, and a flying object present in the surrounding environment.

[0082] [Item 8] The control system according to any one of Items 1 to 7, wherein in the variable geofence mode, the control device predicts the position of a fall point when a rotor of the unmanned aerial vehicle stops, and varies the geofence based on the predicted fall point.

[0083] [Item 9] The control system described in any one of items 1 to 8, wherein in the variable geofence mode, the control device acquires data on at least one of the flight altitude and speed of the unmanned aerial vehicle, and varies the geofence based on the acquired data.

[0084] [Item 10] The control system described in any one of items 1 to 9, wherein in the variable geofence mode, when the unmanned aerial vehicle is flying with a payload attached to the airframe, the control device acquires data on at least one of the weight and center of gravity position of the payload, and varies the geofence based on the acquired data on the payload.

[0085] [Item 11] The control system according to any one of items 1 to 10, wherein the control device, in the dynamic geofence mode, causes the geofence to be displayed on a display device used by a user.

[0086] [Item 12] The control system according to Item 11, wherein the control device causes the display device to display the geofence in accordance with the area of ​​the field.

[0087] [Item 13] The control system according to any one of items 1 to 12, wherein in the dynamic geofence mode, the control device reduces the speed of the unmanned aerial vehicle when the unmanned aerial vehicle approaches the geofence.

[0088] [Item 14] The control system of any one of items 1 to 13, wherein the control device further has a fixed geofence mode that fixes the geofence to a preset boundary while the unmanned aerial vehicle is flying over a field.

[0089] [Item 15] An unmanned aerial vehicle comprising: the control system according to any one of items 1 to 14; and a plurality of rotors controlled by the control system.

[0090] [Item 16] The unmanned aerial vehicle described in Item 15 further comprises: a first rotary drive device that drives a plurality of first rotors included in the plurality of rotors; and a second rotary drive device that drives at least one second rotor included in the plurality of rotors, wherein the first rotary drive device includes a plurality of electric motors that drive the plurality of first rotors respectively, and the second rotary drive device includes an internal combustion engine.

[0091] The unmanned aerial vehicle disclosed herein can be widely used not only for aerial photography, surveying, logistics, and pesticide spraying, but also for ground work related to agricultural work, transporting harvested products and agricultural materials, and the like.

[0092] 2: Rotor (propeller), 3: Rotation drive device, 4: Airframe body, 4a: Control device, 4b: Sensor group, 4c: Communication device, 5: Airframe frame, 10: Multicopter, 12: Sub-rotor, 12a: Propeller, 12b: Propeller, 14: Motor, 16: ESC, 22: Main rotor, 52: Battery

Claims

1. A control system for controlling the flight of an unmanned aerial vehicle, a control device that sets a geofence for the unmanned aerial vehicle and controls the unmanned aerial vehicle to fly within the geofence; The control device has a variable geofence mode that varies the geofence while the unmanned aerial vehicle is flying over a field.

2. The control system of claim 1 , wherein the control device sets the geofence within an area above the field while the unmanned aerial vehicle is flying over the field.

3. The control system of claim 1 , wherein the control device varies the geofence in the variable geofence mode while the unmanned aerial vehicle is flying over a field with a work implement coupled to the airframe.

4. The control system of claim 3, wherein the control device, in the variable geofence mode, varies the geofence while the unmanned aerial vehicle flies over a field with a work implement coupled to the airframe and performs work on the field.

5. The control system of claim 4 , wherein the task comprises a farming task.

6. Further, a sensing device is provided that senses the environment around the unmanned aerial vehicle and outputs sensor data; The control system according to claim 1 , wherein the control device, in the variable geofence mode, varies the geofence based on the sensor data.

7. The control system of claim 6 , wherein the sensor data includes data regarding at least one of wind speed in the surrounding environment, precipitation in the surrounding environment, and flying objects present in the surrounding environment.

8. A control system described in any one of claims 1 to 5, wherein the control device, in the variable geofence mode, predicts the location of the fall point when the rotor of the unmanned aerial vehicle stops, and varies the geofence based on the predicted fall point.

9. The control device, in the dynamic geofence mode, Acquire data on at least one of the flight altitude and speed of the unmanned aerial vehicle; The control system according to claim 1 , wherein the geofence is varied based on the acquired data.

10. The control device, in the dynamic geofence mode, When the unmanned aerial vehicle is flying with a payload connected to the airframe, the unmanned aerial vehicle acquires data on at least one of the weight and the position of the center of gravity of the payload, The control system according to claim 1 , wherein the geofence is varied based on the acquired data on the load.

11. The control system according to claim 1 , wherein the control device, in the dynamic geofence mode, causes the geofence to be displayed on a display device used by a user.

12. The control system according to claim 11 , wherein the control device causes the display device to display the geofence in accordance with the area of the field.

13. The control device, in the dynamic geofence mode, The control system of claim 1 , wherein the control system reduces the speed of the unmanned aerial vehicle when the unmanned aerial vehicle approaches the geofence.

14. The control device 6. The control system of claim 1, further comprising a fixed geofence mode that fixes the geofence to a preset boundary while the unmanned aerial vehicle is flying over a field.

15. A control system according to any one of claims 1 to 5; a plurality of rotors controlled by the control system; An unmanned aerial vehicle comprising:

16. a first rotation drive device that drives a plurality of first rotors included in the plurality of rotors; a second rotation drive device that drives at least one second rotor included in the plurality of rotors; Furthermore, the first rotation drive device includes a plurality of electric motors that drive the plurality of first rotors, respectively; The unmanned aerial vehicle of claim 15 , wherein the second rotary drive comprises an internal combustion engine.