Unmanned flying craft

Abstract

This unmanned flying craft that has a plurality of rotors comprises a power generation device, a first electrical component, a second electrical component, a main battery that can be charged with power generated by the power generation device, a sub-battery, and a charging circuit that connects the second electrical component and the sub-battery. The sub-battery is charged by receiving a supply of power from the second electrical component via the charging circuit, and supplies the charged power to the first electrical component.

Description

unmanned aerial vehicle

[0001] The present disclosure relates to 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] The present disclosure provides a method for monitoring the condition of a battery onboard an unmanned aerial vehicle.

[0006] In an exemplary and non-limiting embodiment, the unmanned aerial vehicle of the present disclosure is an unmanned aerial vehicle with multiple rotors, and includes a power generation device, a first electrical component, a second electrical component, a main battery that can be charged with power generated by the power generation device, a sub-battery, and a charging circuit that connects the second electrical component and the sub-battery, and the sub-battery is charged by receiving power from the second electrical component via the charging circuit, and supplies the charged power to the first electrical component.

[0007] According to an embodiment of the present disclosure, a novel method for monitoring the condition of a battery onboard an unmanned aerial vehicle is provided.

[0008] 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 multicopter. FIG. 7 is a block diagram showing an example basic configuration of a parallel hybrid multicopter. FIG. 8 is a top view schematically showing a multicopter according to an embodiment of the present disclosure. FIG. 9 is a side view schematically showing a multicopter according to this embodiment. FIG. 10 is a block diagram showing an example system configuration of a multicopter according to this embodiment. FIG. 11 is a block diagram showing an example configuration of a power circuit board. FIG. 12 is a flowchart showing an example of a procedure for determining whether to supply power from the main battery to a battery management device and a power supply circuit according to the SOC and SOH of the main battery. FIG. 13 is a block diagram showing an example hardware configuration of a control device according to this embodiment.

[0009] 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."

[0010] 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.

[0011] 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.

[0012] The second rotation drive device 3B shown in FIG. 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. The number of internal combustion engines 7a included in the rotation drive device 3B is not limited to one.

[0013] 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.

[0014] 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."

[0015] 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.

[0016] 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."

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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).

[0021] 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.

[0022] 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, enabling the generation of 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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."

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] FIG. 2A is a block diagram illustrating an example of the basic configuration of a battery-powered multicopter 10. The battery-powered multicopter 10 includes multiple rotors 12, multiple motors 14 for rotating the rotors 12, multiple ESCs (electric speed controllers) 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 multiple ESCs 16 to control attitude and perform 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 illustrates 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Below, an example of the configuration and operation of an unmanned aerial vehicle according to an embodiment of the present disclosure will be described, taking a multicopter that uses parallel hybrid drive as an example.

[0038] <Basic Configuration> Fig. 3A is a schematic top view of the multicopter 100 according to this embodiment, and Fig. 3B is a side view thereof. Fig. 3B illustrates a work implement 200 coupled to the multicopter 100. In addition to or instead of the work implement 200, luggage, agricultural materials, other machinery, or containers, cases, or packages capable of accommodating these items may be coupled to the multicopter 100. Hereinafter, the weight of the work implement 200 and the work implement itself may be referred to as the "payload." The "coupling" between the multicopter 100 and the work implement 200 or the like may be performed using various tools or devices.

[0039] The multicopter 100 shown in FIG. 3A includes eight sub-rotors 12 and two main rotors 22. Each sub-rotor 12 is composed of four sets of propellers 12a and 12b that rotate coaxially and in opposite directions. Each of the propellers 12a and 12b has two blades. The propellers 12a and 12b are rotated by a motor 14. The four sets of propellers 12a and 12b that rotate coaxially and in opposite directions are located at the vertices of a square. The main rotor 22 is composed of two propellers 22a that rotate in opposite directions at different positions. Each propeller 22a has four blades. The eight propellers 12a and 12b of the sub-rotor 12 have the same pitch angle and diameter. The two propellers 22a of the main rotor 22 also have the same pitch angle and diameter. The diameter of the propeller 22a is 1.2 times or more, for example, 1.4 times or more and 2.0 times or less, the diameter of the propellers 12a and 12b.

[0040] The multicopter 100 includes an airframe 110 having four arms 110A for the sub-rotors 12 and two arms 110B for the main rotors 22. The airframe 110 supports an airframe body 120 including various electronic and mechanical components, which will be described later.

[0041] In the example of FIG. 3B , the airframe main body 120 has a power supply device 76 and an actuator 78 used for coupling to the work machine 200, etc. The power supply device 76 is a device that supplies power generated within the airframe main body 120 to the work machine 200. The actuator 78 is a device such as an electric motor that performs an operation to couple the work machine 200 to the airframe main body 120 of the multicopter 100. In the example of FIG. 3B , the actuator 78 drives a mechanism that winds up a cable connecting the airframe main body 120 and the work machine 200. This cable may include a power supply line for supplying power from the multicopter 100 to the work machine 200, and a communication line for communication between the multicopter 100 and the work machine 200.

[0042] <System Configuration> FIG. 4 is a block diagram showing an example of a system configuration of the multicopter 100 according to this embodiment.

[0043] In the illustrated example, the airframe 120 of the multicopter 100 has a control device 30 including a flight controller 32, a sensor group 72, and a communication device 74. These are basically the same as the control device 4a, the sensor group 4b, and the communication device 4c of the airframe 4 of the multicopter 10 described with reference to FIG. 1A.

[0044] The multicopter 100 of this embodiment includes eight sub-rotors 12, eight motors 14 for rotating the eight sub-rotors 12, and eight ESCs for controlling the eight motors 14. Each ESC 16 receives a signal (motor control signal) for controlling the motor 14 from the control device 30 via a wiring 82. The motor control signal is, for example, a PWM (Pulse With Modulation) signal. When the motor control signal is a PWM signal, the duty cycle of the PWM signal can indicate an analog value of the motor rotation speed. Each ESC 16 controls the rotation speed of the motor 14 connected to that ESC 16 based on the motor control signal from the control device 30. While FIG. 4 illustrates one set of "sub-rotors 12, motors 14, and ESCs 16" for simplicity, the multicopter 100 of this embodiment includes eight sets of "sub-rotors 12, motors 14, and ESCs 16." The number of these sets is not limited to eight.

[0045] The control device 30 is connected to each of the ESCs 16 via electrically independent wiring 82, and can individually control each of the eight ESCs 16. As described above, the sub-rotors 12 are used not only to generate lift but also for attitude control. Attitude control is achieved by the flight controller 32 of the control device 30 obtaining measured or estimated values ​​indicating the attitude of the airframe 120 from the sensors 72, determining the current attitude of the airframe 120, and controlling the rotational speed of each of the motors 14 in accordance with the difference from the target attitude.

[0046] The aircraft body 120 includes a main rotor drive unit 24 that drives the main rotor 22 and a main rotor control unit 26 that controls the main rotor drive unit 24. In this embodiment, the main rotor drive unit 24 is an internal combustion engine. Therefore, the main rotor control unit 26 includes an engine control unit (ECU). The main rotor control unit 26 acquires sensor data such as the accelerator opening, intake air temperature, engine speed, and temperatures of various components of the main rotor drive unit 24, which is an internal combustion engine, and controls the internal combustion engine. The main rotor control unit 26 is connected to the control device 30 via wiring 82, such as a CAN (Controller Area Network) bus. The main rotor control unit 26 is configured to output an engine control signal based on a signal transmitted from the control device 30. The engine control signal includes, for example, a throttle opening. A digital-to-analog converter (DAC) and / or a voltage converter may be connected between the control device 30 and the main rotor control unit 26. A mechanical device such as a reducer may be provided between the main rotor drive section 24 and the main rotor 22.

[0047] The main rotor drive unit 24 is preferably an internal combustion engine with little vibration. In this embodiment, the main rotor drive unit 24 is, for example, an opposed-piston engine. Opposed-piston engines are disclosed, for example, in Japanese Patent No. 5508604. The entire contents of Japanese Patent No. 5508604 are incorporated herein by reference.

[0048] The main rotor drive unit 24, which is an internal combustion engine, can generate electricity by driving a power generator 42, such as an alternator. In this embodiment, the power generator 42 has the structure of an AC synchronous motor having a rotor and a stator. Therefore, when the main rotor drive unit 24 is started, the power generator 42 can also function as a "starter" by rotating the rotor when current is applied. The power generator 42 rectifies the AC generated by power generation and converts it into DC. The power generator 42 generates DC power required to drive the motor 14 and supplies it to each ESC 16 via wiring 80. The power generator 42 is configured to output a DC voltage of, for example, 250 V or higher. Note that the wiring 80 is a power wiring, and the wiring 82 is a signal wiring. Each of the wirings 80 and 82 includes multiple conductors.

[0049] The power generation device 42 is connected to a power management device 44. The power management device 44 is connected to the control device 30 and a battery management device 54, which will be described later. The power management device 44 can control the amount of power generated by the power generation device 42 based on signals from the control device 30 or the battery management device 54. This amount of power generation can be variably controlled by the power management device 44 in accordance with the power required by the motor 14 and the battery 52, even when the engine speed of the main rotor drive unit 24, which is an internal combustion engine, is constant.

[0050] The aircraft body 120 further includes a battery 52 in the form of a plurality of cells, for example, lithium ion secondary batteries, connected in series or in parallel, and a battery management device 54 that controls the charging and discharging of the battery 52 .

[0051] The battery 52 receives DC power from the power generation device 42 via a power switch 56 and can be charged by the power. The operation of the power switch 56 can be controlled by a battery management unit 54 and the control device 30. The battery management unit 54 is a device that measures or estimates parameter values ​​that define the state of the battery 52, such as the current flowing through the battery 52, cell voltage, cell balance, state of charge (SOC), state of health (SOH), and temperature.

[0052] The battery management unit 54 can control the power switch 56 depending on the state of the battery 52. ​​For example, when the battery 52 is in a state requiring charging, the battery management unit 54 electrically connects the power generation device 42 and the battery 52 using the power switch 56, and supplies power from the power generation device 42 to the battery 52 to perform a charging operation. At this time, the battery management unit 54 controls the power management unit 44 to increase the amount of power generated by the power generation device 42 so that the power supplied to the ESC 16 does not drop below a desired level. On the other hand, when the battery 52 is in a state requiring no charging, the battery management unit 54 disconnects the electrical connection between the power generation device 42 and the battery 52 using the power switch 56, and stops charging the battery 52.

[0053] In this embodiment, the battery 52 has a storage capacity that allows the aircraft to continue to fly to a location where landing is possible and land there, by continuing to generate lift and control attitude using the sub-rotor 12, even if power generation by the power generation device 42 stops for some reason and lift from the main rotor 22 is lost. In other words, when the multicopter 100 of this embodiment is flying normally, the power required to drive the sub-rotor 12 can be supplied to the ESC 16 from the power generation device 42, rather than from the battery 52. ​​Therefore, even if the payload and flight time are increased, there is little need to increase the storage capacity of the battery 52 accordingly.

[0054] The power stored in the battery 52 can be output as a DC voltage of, for example, 250 V or higher. However, this DC voltage decreases as the charging rate decreases. Therefore, when the charging rate falls below a predetermined level, the battery management device 54 operates to supply part of the DC power from the power generation device 42 to the battery 52 to charge the battery 52.

[0055] The battery 52 is connected to a power circuit board 60. The power circuit board 60 has a function of stepping down the voltage output from the battery 52 to, for example, 24 V, 12 V, or 5 V. The DC voltage output from the battery 52 is converted to a desired voltage by the power circuit board 60 and then supplied to other electronic components.

[0056] 4 , the power supply device 76 is electrically connected to the power generation device 42 or the battery 52 by a power switch 56. The power supply device 76 in this example is configured to supply power generated within the machine body 120 to an external machine or device such as a work machine 200.

[0057] The airframe main body 120 may have a configuration not shown in FIG. 4 . For example, the airframe main body 120 may include a fuel tank that stores fuel necessary for the operation of the main rotor drive unit 24, a water-cooling or air-cooling device for cooling the main rotor drive unit 24, and electrical components such as lighting devices and an electric pump. The electrical components can be operated by power that has been stepped down to a predetermined voltage by the power circuit board 60. A battery for the electrical components (auxiliary battery) may be provided and configured to supply power to the electrical components. Such an auxiliary battery may be charged by the battery 52 or the power generation device 42.

[0058] In this embodiment, the motor 14 functions as a plurality of "attitude control devices" that respectively drive a plurality of first rotors (sub-rotors) 12. In addition, the main rotor drive unit 24, which is an internal combustion engine, functions as a "main thrust generating device" that drives the second rotor (main rotor) 22.

[0059] In this embodiment, the control device 30 is capable of changing the ratio (power ratio) between the first drive power output from the multiple motors 14 and the second drive power output from the main rotor drive unit 24.

[0060] Generally, the responsiveness of the motor 14 is superior to that of an internal combustion engine. If the time from when a torque command signal is input until the torque required to rotate the rotors 12, 22 reaches a target torque value is called the "response time," the response time of the motor is, for example, approximately 1 / 100 of the response time of the internal combustion engine. Therefore, to control the attitude of the multicopter 100, it is desirable to detect the difference between the current and target attitude angles of the multicopter 100 and control the rotational speed of each of the multiple sub-rotors 12 with a high response speed so as to reduce this difference. An increase in rotor rotational speed results in an increase in thrust. By adjusting the thrust of each of the multiple sub-rotors 12, the attitude of the multicopter 100 can be controlled quickly and with high precision.

[0061] On the other hand, an internal combustion engine can efficiently generate large thrust. The sub-rotor 12 is rotated using electric power generated by the power of the main rotor drive unit 24, which is an internal combustion engine. However, energy loss occurs when converting mechanical energy into electrical energy. Therefore, from the viewpoint of improving energy consumption efficiency, it is preferable that the main rotor drive unit 24 be used to rotate the main rotor 22 and generate the main thrust. Furthermore, to increase the thrust of the main rotor 22, it is preferable that the diameter of the main rotor 22 be larger than the diameter of each of the multiple first rotors 12.

[0062] In one aspect, the multicopter according to this embodiment includes a power generation device, a battery capable of being charged with power generated by the power generation device, a first electrical component, a second electrical component, a sub-battery, and a charging circuit connecting the second electrical component and the sub-battery. The sub-battery may be mounted on a power circuit board. The sub-battery is charged by receiving power from the second electrical component via the charging circuit, and supplies the charged power to the first electrical component.

[0063] The first electrical component monitors the power of the battery. In this embodiment, the first electrical component is, for example, the battery management device 54. Hereinafter, the battery 52 will be referred to as the main battery 52 to distinguish it from the sub-battery.

[0064] FIG. 5 is a block diagram showing an example of the configuration of the power circuit board 60. As shown in FIG.

[0065] 5, a power circuit board 60 includes a power supply circuit 61, a sub-battery 62, and a charging circuit 68 provided between the output terminal Vout of the power supply circuit 61 and the sub-battery 62. The charging circuit 68 includes a diode element 63 and a resistor element 64 connected in series.

[0066] An example of the power supply circuit 61 is a DC-DC converter. The power supply circuit 61 generates a DC voltage by stepping down the battery voltage of the main battery 52. ​​As described above, the power circuit board 60 has the function of stepping down the voltage output from the main battery 52 to, for example, 24 V, 12 V, or 5 V. In this embodiment, the battery voltage of the main battery 52 is 288 V. In other words, the DC voltage output from the battery 52 is 288 V. However, this voltage value is an example, and the DC voltage may be, for example, 250 V or higher. The power supply circuit 61 in this embodiment is a DC-DC converter that steps down the battery voltage of 288 V to a DC voltage of 24 V. The DC voltage is not limited to 24 V. In this way, a DC voltage of 24 V is output from the output terminal Vout of the power supply circuit 61 in the example shown in FIG. 5.

[0067] The power circuit board 60 may further include a DC-DC converter for stepping down the 24V DC voltage output from the power supply circuit 61 to, for example, 12V DC. The 12V DC voltage may be supplied to multiple electrical components, including, for example, the main rotor control unit 26 (ECU), a decompression control device, a water pump, and a fuel pump. The decompression control device is a device for controlling the decompression operation of the main rotor drive unit 24, which is an internal combustion engine. An example of a decompression control device is a solenoid. A solenoid is a type of motor. The aircraft body 120 is provided with a water-cooling system for cooling the main rotor drive unit 24. The water-cooling system includes, for example, a water pump, a radiator, a radiator fan, and a thermostat. The water pump is an electrical component for controlling the circulation of coolant (cooling water) supplied to the main rotor drive unit 24. The fuel pump is an electrical component for supplying fuel from a fuel tank to the main rotor drive unit 24.

[0068] The sub-battery 62 is electrically connected between the output terminal Vout of the power supply circuit 61 and GND. Power is supplied to the sub-battery 62 from the output terminal Vout of the power supply circuit 61. In this embodiment, the sub-battery 62 is composed of, for example, six 4.3 V batteries connected in series. That is, the battery voltage of the sub-battery 62 is 25.8 V, which is higher than the 24 V DC voltage output from the output terminal Vout of the power supply circuit 61. In other words, the battery voltage of the sub-battery 62 in a fully charged state is higher than the voltage output from the output terminal Vout of the power supply circuit 61.

[0069] The sub-battery 62 is connected to the output terminal Vout of the power supply circuit 61 via a series-connected diode element 63 and resistor element 64. More specifically, the positive electrode of the sub-battery 62 is connected to the output terminal Vout of the power supply circuit 61 via the diode element 63 and resistor element 64, and the negative electrode of the sub-battery 62 is connected to ground. The resistance value of the resistor element 64 is, for example, about 10 ohms.

[0070] When the sub-battery 62 is fully charged, the potential of the positive electrode of the sub-battery 62 (25.8 V) is greater than the 24 V DC voltage output from the output terminal Vout of the power supply circuit 61. Therefore, due to the rectification action of the diode element 63, no current flows from the power supply circuit 61 to the resistor element 64. In contrast, when the charge rate of the sub-battery 62 decreases and the potential of the positive electrode of the sub-battery 62 falls below 24 V, a potential difference occurs between the positive electrode of the sub-battery 62 and the output terminal Vout. When this potential difference exceeds the threshold voltage of the diode element 63, current flows from the power supply circuit 61 to the sub-battery 62 via the resistor element 64. In other words, power is supplied from the main battery 52 to the sub-battery 62. In this way, when the charge rate of the sub-battery 62 decreases, it is possible to charge the sub-battery 62 using a relatively simple circuit.

[0071] The multicopter in this embodiment includes a switching circuit that switches whether or not power is supplied from the sub-battery 62 to the battery management device 54. As illustrated in FIG. 5 , the switching circuit includes a switch SW that places the battery management device 54 and the sub-battery 62 in electrical conduction when the battery management device 54 is started. In other words, the switching circuit places the battery management device 54 and the sub-battery 62 in electrical conduction in response to the start of the internal combustion engine (or the main rotor drive unit). This allows power to be supplied from the sub-battery 62 to the battery management device 54.

[0072] 5 , a switch SW of the switching circuit is electrically connected between the battery management device 54 and the sub-battery 62. An example of the switch SW is an ignition switch. When the switch SW is turned on, power starts to be supplied from the sub-battery 62 to the battery management device 54. In response to the start of the supply of startup power from the sub-battery 62, the battery management device 54 is configured to determine whether or not to supply power from the main battery 52 to the battery management device 54 and the power supply circuit 61, depending on the state of the main battery 52.

[0073] In this embodiment, as described above, the battery management unit 54 measures or estimates parameter values ​​that define the state of the main battery 52, such as the current flowing through the main battery 52, the cell voltage, the cell balance, the SOC, the SOH, the temperature, and the amount of power, and determines whether or not to supply power from the main battery 52 to the battery management unit 54 and the power supply circuit 61 based on the measured or estimated parameter values. A threshold value used to determine whether or not to supply power may be set for each parameter value. For example, the battery management unit 54 may prohibit the supply of power from the main battery 52 to the battery management unit 54 and the power supply circuit 61 if any one of these parameter values ​​is below the threshold value. The battery management unit 54 may permit the supply of power from the main battery 52 to the battery management unit 54 and the power supply circuit 61 if all of these parameter values ​​are equal to or greater than the threshold value.

[0074] An example of a procedure for determining whether or not to supply power from the main battery 52 to the battery management device 54 and the power supply circuit 61 in accordance with the SOC and SOH of the main battery 52 will be described with reference to FIG.

[0075] 6 is a flowchart showing an example of a procedure for determining whether or not to supply power from the main battery 52 to the battery management device 54 and the power supply circuit 61, depending on the SOC and SOH of the main battery 52. ​​In the procedure shown in FIG. 6, the battery management device 54 determines whether or not to supply power from the main battery 52 to the battery management device 54 and the power supply circuit 61, based on the measured or estimated SOC and SOH of the main battery 52.

[0076] In this embodiment, the sub-battery 62 is already fully charged before the switch SW is turned on. As described above, while the power supply circuit 61 is operating, power is supplied from the main battery 52 to the sub-battery 62 in accordance with the potential difference generated between the positive electrode of the sub-battery 62 and the output terminal Vout of the power supply circuit 61.

[0077] Here, before the main rotor drive unit 24 is started, i.e., before the multicopter is taken off, the switch (ignition switch) SW is off. Also, while the switch (ignition switch) SW is off, no power is supplied from the main battery 52 to the electrical components. In other words, no power is supplied from the power supply circuit 61 to the electrical components. When the multicopter is to take off, first, a startup command is sent to the multicopter from an external controller (pilot) or management device, etc. In response to this, the switch (ignition switch) SW is turned on, and the supply of startup power from the sub-battery 62 to the battery management device 54 begins (step S10).

[0078] Next, in response to the start of the supply of startup power, the battery management unit 54 measures or estimates the SOC and SOH of the main battery 52 (step S20). Based on the measured or estimated SOC and SOH of the main battery 52, the battery management unit 54 determines whether or not to supply power from the main battery 52 to the battery management unit 54 and the power supply circuit 61. Specifically, if the SOC is equal to or greater than a threshold (YES in step S30) and the SOH is equal to or greater than a threshold (YES in step S40), the battery management unit 54 permits the supply of power from the main battery 52 to each electrical component (step S50). On the other hand, if the SOC is less than the threshold (NO in step S30), or if the SOC is equal to or greater than the threshold (YES in step S30) and the SOH is less than the threshold (NO in step S40), the battery management unit 54 prohibits the supply of power from the main battery 52 to each electrical component (step S60).

[0079] In this way, power is supplied to the battery management device 54 from the sub-battery 62, not from the main battery 52. ​​Before activating the battery management device 54 and supplying power from the main battery 52 to the battery management device 54 and the power supply circuit 61, the battery management device 54 is made to check the status of the main battery 52. ​​As a result, if there is no problem with the status of the main battery 52, stable power is supplied from the main battery 52 to the electrical components. Supplying stable power to the electrical components makes it possible to effectively prevent malfunctions of the electrical components that may occur due to, for example, a power shortage.

[0080] 7 is a block diagram showing an example of the hardware configuration of the control device 30. The control device 30 includes a processor 34, a ROM (Read Only Memory) 35, a RAM (Random Access Memory) 36, a storage device 37, and a communication I / F 38. These components are connected to each other via a bus 39.

[0081] 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).

[0082] 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.

[0083] 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.

[0084] The communication I / F 38 is an interface for communication between the control device 30 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 also 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 that use frequencies in the 2.4 GHz band.

[0085] 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.

[0086] 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 FIG. 6 and issue commands related to power monitoring based on the results of those processes to the battery management device 54. Some or all of the functions of the electrical components, such as the control device 4a and battery management device 54, mounted on the multicopter 100 may be implemented by one or more servers (computers) or terminal devices (including portable and fixed types) connected to the communication device 4c of the multicopter 100 via a communication network.

[0087] A system providing various functions in the embodiments can also be retrofitted to a multicopter that does not have those functions. Such a system can be manufactured and sold independently of the multicopter. A computer program used in such a system can also be manufactured and sold independently of the multicopter. The computer program can be provided, for example, by being stored in a computer-readable non-transitory storage medium. The computer program can also be provided by downloading via a telecommunications line (e.g., the Internet).

[0088] This specification discloses the solutions described in the following items.

[0089] [Item 1] An unmanned aerial vehicle having multiple rotors, comprising: a power generation device; a first electrical component; a second electrical component; a main battery capable of being charged with power generated by the power generation device; a sub-battery; and a charging circuit connecting the second electrical component and the sub-battery, wherein the sub-battery is charged by receiving power from the second electrical component via the charging circuit, and supplies the charged power to the first electrical component.

[0090] [Item 2] The unmanned aerial vehicle according to Item 1, further comprising a switching circuit that switches whether or not power is supplied from the sub-battery to the first electrical component.

[0091] [Item 3] The unmanned aerial vehicle according to Item 2, wherein the switching circuit brings the first electrical component and the sub-battery into an electrically conductive state when the first electrical component is started.

[0092] [Item 4] An unmanned aerial vehicle according to any one of items 1 to 3, comprising an internal combustion engine, wherein the power generation device is driven by the internal combustion engine to generate electric power.

[0093] [Item 5] The unmanned aerial vehicle described in Item 4, wherein the first electrical component determines whether to supply power from the main battery to the first and second electrical components in response to the start of the power supply from the sub-battery, depending on the state of the main battery.

[0094] [Item 6] The unmanned aerial vehicle described in Item 5, wherein the second electrical equipment is a power supply circuit that reduces the battery voltage of the main battery to generate a stepped-down voltage, the sub-battery is electrically connected between an output terminal of the power supply circuit and GND, and power is supplied to the sub-battery from the output terminal via the charging circuit.

[0095] [Item 7] The unmanned aerial vehicle according to Item 6, wherein the charging circuit includes a resistor element and a diode element connected in series.

[0096] [Item 8] The unmanned aerial vehicle described in Item 7, wherein the resistance value of the resistive element is several tens of ohms.

[0097] [Item 9] An unmanned aerial vehicle according to any one of items 6 to 8, wherein the battery voltage of the sub-battery in a fully charged state is greater than the voltage output from the output terminal.

[0098] [Item 10] An unmanned aerial vehicle described in any one of items 1 to 9, comprising a plurality of electric motors that respectively drive a plurality of first rotors included in the plurality of rotors, and the internal combustion engine drives at least one second rotor included in the plurality of rotors.

[0099] 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.

[0100] 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, 54: Battery management device

Claims

1. 1. An unmanned aerial vehicle having multiple rotors, a power generation device; A first electrical component; A second electrical component; a main battery that can be charged with the power generated by the power generation device; A sub-battery, a charging circuit connecting the second electrical component and the sub-battery; Equipped with The sub-battery is charged by receiving power from the second electrical component via the charging circuit, and supplies the charged power to the first electrical component.

2. The unmanned aerial vehicle according to claim 1 , further comprising a switching circuit that switches whether or not power is supplied from the sub-battery to the first electrical component.

3. The unmanned aerial vehicle according to claim 2 , wherein the switching circuit brings the first electrical component and the sub-battery into an electrically conductive state when the first electrical component is started.

4. Equipped with an internal combustion engine, The unmanned aerial vehicle according to claim 1 , wherein the power generation device is driven by the internal combustion engine to generate electric power.

5. 5. The unmanned aerial vehicle described in claim 4, wherein the first electrical component determines whether or not to supply power from the main battery to the first and second electrical components in response to the start of power supply from the sub-battery, depending on the state of the main battery.

6. the second electrical component is a power supply circuit that generates a stepped-down voltage by stepping down a battery voltage of the main battery, the sub-battery is electrically connected between the output terminal of the power supply circuit and GND; The unmanned aerial vehicle according to claim 5 , wherein power is supplied from the output terminal to the sub-battery via the charging circuit.

7. The unmanned aerial vehicle of claim 6 , wherein the charging circuit comprises a resistor element and a diode element connected in series.

8. The unmanned aerial vehicle according to claim 7, wherein the resistance value of the resistive element is several tens of ohms.

9. The unmanned aerial vehicle according to claim 6 , wherein the battery voltage of the sub-battery in a fully charged state is greater than the voltage output from the output terminal.

10. a plurality of electric motors that respectively drive a plurality of first rotors included in the plurality of rotors; The unmanned aerial vehicle according to claim 1 , wherein the internal combustion engine drives at least one second rotor included in the plurality of rotors.