Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U10/00—Type of UAV
  • B64U10/10—Rotorcrafts
  • B64U10/13—Flying platforms
  • B64U10/16—Flying platforms with five or more distinct rotor axes, e.g. octocopters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U50/00—Propulsion; Power supply
  • B64U50/10—Propulsion
  • B64U50/11—Propulsion using internal combustion piston engines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U50/00—Propulsion; Power supply
  • B64U50/10—Propulsion
  • B64U50/19—Propulsion using electrically powered motors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U50/00—Propulsion; Power supply
  • B64U50/20—Transmission of mechanical power to rotors or propellers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U50/00—Propulsion; Power supply
  • B64U50/30—Supply or distribution of electrical power
  • B64U50/33—Supply or distribution of electrical power generated by combustion engines

Definitions

• This disclosure relates to an unmanned aerial vehicle and a method for controlling the same.
• Unmanned aerial vehicles are aircraft that cannot accommodate people due to their structure, but can fly remotely or automatically.
• 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 are also called “drones,” “multirotors,” or “multicopters,” and are widely used for aerial photography, surveying, logistics, and pesticide spraying.
• Patent Document 1 describes an unmanned aerial vehicle (unmanned flying object) that changes its flight position in conjunction with the operation of agricultural machinery.
• FIG. 1 is a block diagram illustrating schematic examples of rotary drive devices that rotate rotors in an unmanned aerial vehicle having multiple rotors.
• 1 is a plan view showing a schematic diagram of one basic configuration example of an unmanned aerial vehicle equipped with multiple rotors.
• 1 is a side view showing a schematic diagram of one basic configuration example of an unmanned aerial vehicle equipped with multiple rotors.
• FIG. 13 is a plan view showing a schematic diagram of another basic configuration example of an unmanned aerial vehicle having multiple rotors.
• FIG. 1 is a block diagram showing an example of a basic configuration of a battery-powered multicopter.
• FIG. 1 is a block diagram showing an example of a basic configuration of a series hybrid type multicopter.
• Unmanned aerial vehicles with multiple rotors are equipped with a rotary drive device that rotates the rotors (hereinafter sometimes referred to as “propellers”).
• pumps a rotary drive device that rotates the rotors
• multicopters such unmanned aerial vehicles will be referred to as "multicopters.”
• the second rotary drive device 3B shown in FIG. 1A has a power transmission system 23 mechanically connected to the rotor 2, and an internal combustion engine 7a that provides a driving force (torque) to the power transmission system 23.
• the power transmission system 23 includes mechanical components such as gears or belts, and transmits the torque of 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 may include a gasoline engine, a diesel engine, and a hydrogen engine. Furthermore, the number of internal combustion engines 7a included in the rotary drive device 3B is not limited to one.
• FIG. 1B is a plan view that shows a schematic example of one basic configuration of multicopter 10.
• the configuration example of FIG. 1B includes a first rotation drive device 3A shown in FIG. 1A as the rotation drive device 3. That is, the rotation drive device 3 (3A) in this example includes a motor 14 and a battery 52.
• FIG. 1C is a side view that shows a schematic example of multicopter 10.
• 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, making it possible to generate the desired thrust.
• Each of the rotors 2 generally has multiple blades with a fixed pitch angle, and generates thrust by rotation.
• the pitch angle may be variable. It is not necessary for all of the rotors 2 to have the same diameter (propeller diameter), and one or more rotors 2 may have a larger diameter than the other rotors 2.
• the thrust (static thrust) generated by the rotating rotor 2 is generally proportional to the cube of the diameter of the rotor 2. For this reason, when rotors 2 with different diameters are provided, the rotor 2 with a relatively large diameter may be called the "main rotor" and the rotor 2 with a relatively small diameter may be called the "sub rotor".
• the control device 4a can receive control commands wirelessly from, for example, a ground station 6 on the ground via the communication device 4c.
• the number of ground stations 6 is not limited to one, and may be distributed in multiple locations.
• the communication device 4c can also receive control commands wirelessly from a control device of a pilot on the ground.
• the control device 4a may have a function to automatically or autonomously perform each operation of takeoff, flight, obstacle avoidance, and landing 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 obtain a signal indicating the state 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.
• 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 may be performed by wire or wirelessly.
• FIG. 2C is a block diagram showing an example of the basic configuration of a parallel hybrid drive type multicopter 10.
• the parallel hybrid drive type multicopter 10 like the series hybrid drive type multicopter 10, includes a plurality of rotors 12, a plurality of motors 14 for driving the rotors 12, a plurality of ESCs 16, a control device 4a, a group of sensors 4b, a communication device 4c, an internal combustion engine 7a, a fuel tank 7b, a power generation device 8, a power buffer 9, and a power supply device 76.
• the aircraft body 120 has a power supply device 76 and an actuator 78 used for connecting to the work machine 200.
• the power supply device 76 is a device that supplies power generated within the aircraft body 120 to the work machine 200.
• the actuator 78 is a device such as an electric motor that performs an operation for connecting the work machine 200 to the aircraft body 120 of the multicopter 100.
• the actuator 78 drives a mechanism that winds up a cable connecting the aircraft 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.
• FIG. 4 is a block diagram showing an example of a system configuration of the multicopter 100 of this embodiment.
• the aircraft body 120 of the multicopter 100 has a control device 30 including a flight controller 32, a sensor group 72, and a communication device 74. This is basically the same as the control device 4a, the sensor group 4b, and the communication device 4c of the aircraft body 4 of the multicopter 10 described with reference to FIG. 1A.
• the control device 30 is connected to each ESC 16 via electrically independent wiring 82, and can control each of the eight ESCs 16 individually.
• the sub rotor 12 is 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 main body 120 from the sensor group 72, determining the current attitude of the main body 120, and controlling the rotational speed of each motor 14 according to the difference from the target attitude.
• the storage capacity of the battery 52 has a value that allows the aircraft to continue to generate lift and control attitude by the sub-rotor 12 and fly to a location where landing is possible and land there, even if power generation by the power generation device 42 stops for some reason and lift by the main rotor 22 is lost.
• the power required to drive the sub-rotor 12 can be supplied to the ESC 16 from the power generation device 42, not from the battery 52. For this reason, even if the payload and flight time are increased, there is little need to increase the storage capacity of the battery 52 accordingly.
• the multicopter 100 when used for, for example, agricultural work, it is preferable to make the above-mentioned "thrust ratio" variable rather than fixed, compared to when the multicopter 100 is flown simply for logistics or surveillance purposes.
• the multicopter 100 flies under a variety of different conditions, such as various agricultural tasks (ground tasks) within a field, movement between multiple fields, and transporting agricultural materials or harvested products, and the level of response speed required for attitude control varies greatly depending on these conditions.
• the required lift and the accuracy of attitude control can also vary greatly.
• the multicopter 100 In the field F2, the multicopter 100 during ground work moves along a predetermined route while performing precise attitude control.
• the control device 30 reduces the second thrust of the main rotor 22 and increases the first thrust of the sub-rotor 12 compared to when moving between fields.
• the control device 30 of the multicopter 100 in order for the multicopter 100 to appropriately change the thrust ratio depending on the work content, it is desirable for the control device 30 of the multicopter 100 to obtain information regarding a work plan that specifies the work content.
• This information may include, for example, information specifying the content of the work to be performed in the fields F1 and F2 in FIG. 5, the scheduled start time, and the scheduled end time, information on waypoints that specify the flight paths P1 to P5, the scheduled arrival time in areas A1 and A2, waiting time, and the scheduled departure time.
• the creation of such a work plan that specifies the work content is described below.
• the management device 600 may create a work plan based not only on information indicating the approximate timing of agricultural work, but also on information input by each user using the terminal device 400. For example, the management device 600 may create a work plan based on information indicating a rough plan for each type of agricultural work in one or more fields managed by each user.
• FIG. 8 shows an example of a setting screen 760 when tilling with fertilizer spraying is performed as an agricultural task in a rice field.
• the setting screen 760 is not limited to the one shown in the figure, and can be modified as appropriate.
• the setting screen 760 in the example of FIG. 8 includes a period setting section 761, a time setting section 762, a plant variety selection section 763, a field selection section 764, a task selection section 765, a machine selection section 766, a fertilizer selection section 767, and a spray amount setting section 768.
• the time setting section 762 displays the work time input by the user.
• the user inputs the work time for which the user wishes to perform the farm work.
• the work time is specified by a start time and an end time.
• the input work time is set as a candidate for the time when the farm work will be performed.
• the crop variety selection section 763 displays a list of crop varieties to be cultivated (i.e., planted). The user can select the desired variety from the list. In the example of Figure 8, the rice variety "Koshiibuki" has been selected.
• the field selection section 764 displays the fields on the map. The user can select any field from the displayed fields. In the example of Figure 8, the portion showing "Field A" is selected. In this case, the selected “Field A” is set as the field where agricultural work will be carried out. The user can also select multiple fields at the same time.
• the task selection section 765 displays multiple farm tasks necessary to cultivate the selected crop.
• the user can select one farm task from among the multiple farm tasks.
• "plowing" has been selected from among the multiple farm tasks.
• the selected "plowing” is set as the farm task to be performed.
• the machine selection section 766 is a section for setting the multicopter to be used in the agricultural work.
• the type or model of the multicopter registered in advance by the management device 600, and the type or model of the work implement 200 that can be used, etc. can be displayed in the machine selection section 766.
• the user can select a specific machine from the displayed machines.
• a work implement 200 with the model number "XX4511" is selected. In this case, that work implement 200 is set as the machine to be used in the agricultural work.
• the spray amount setting section 770 displays the numerical value input from the input device 420.
• the input numerical value is set as the spray amount.
• the communication device of the terminal device 400 transmits the entered information to the management device 600.
• the processor of the management device 600 stores the received information in a storage device.
• the information on agricultural work managed by the management device 600 is not limited to the above.
• the type of pesticide to be used in the field and the amount to be sprayed may be set on the setting screen 760.
• Information on agricultural work other than the agricultural work shown in FIG. 8 may also be set.
• the management device 600 creates a work plan for each multicopter 100 to perform agricultural work based on information received from each user's terminal device 400. For example, the management device 600 determines the actual work date and work time of the agricultural work to be performed by each multicopter 100. For example, the management device 600 determines the date and time of agricultural work in each field by comprehensively considering the number, distribution, and usage status of the multicopter 100, the distribution of fields in which agricultural work is performed in the area, the work date and time desired by each user, and the estimated work period in the area. An algorithm using artificial intelligence (AI), such as a deep neural network, may be used to determine the date and time of agricultural work in each field. The management device 600 notifies the terminal device 400 used by the user of the determined date and time of agricultural work.
• AI artificial intelligence
• the management device 600 executes a route plan for each multicopter 100 for each work day based on the determined date and time when the agricultural work will be performed in each field.
• the control device 30 in this embodiment can obtain the work content of the multicopter 100 and change the thrust ratio based on the flight and work content defined in the work plan.
• the thrust ratio can be made smaller than a predetermined reference value, and when moving toward the next work site, which is a farm field, the thrust ratio can be made equal to or greater than the reference value.
• step S10 the control device 30 obtains the initial value of the second thrust of the main rotor 22 (output of the main thrust generating device) and the initial value of the second thrust of the sub-rotor 12 (output of the attitude control device).
• step S12 the control device 30 acquires the flight conditions that are currently being executed or will be executed in the future.
• the flight conditions may be specified by a control signal sent from an operator or a ground station. They may also be specified by a pre-set work plan.
• the control device 30 can determine the flight conditions by referring to the work plan based on the current position and current time of the multicopter 100 obtained from the sensor group.
• the flight conditions may be divided into a plurality of flight modes.
• the plurality of flight modes may include, for example, a first flight mode in which the ratio (thrust ratio) of the second thrust of the main rotor 22 to the first thrust of the sub-rotor 12 is variable, and a second flight mode in which this thrust ratio is fixed.
• the flight modes may include, for example, modes such as hovering, horizontal flight (forward, backward, or lateral movement (aileron)), ascent, descent, and rotation (rudder).
• the control device 30 may set the thrust ratio to a value, for example, greater than 1, during ascent and hovering, for example. This allows the main rotor 22 to efficiently generate a large thrust.
• the control device 30 may set the thrust ratio to a value smaller than the value during hovering (for example, a value smaller than 1) when adjusting the attitude (yaw, pitch, and/or roll) of the aircraft to a desired attitude, for example, for landing, horizontal flight, or rudder operations. This prevents the large thrust and rotational moment generated by the rotation of the main rotor 22 from interfering with the attitude control function of the sub-rotor 12.
• the control device 30 may be configured to change the thrust ratio in response to a user's operation using an external device such as a pilot or a remote monitoring device. This allows the user to adjust the balance between thrust generation efficiency and attitude control responsiveness, for example, to make it easier for the user to pilot the vehicle.
• step S14 the control device 30 acquires weather information including information indicating wind speed.
• the control device 30 may acquire wind speed measurements from a group of sensors, or may acquire weather information from a ground station via communication.
• step S16 the control device 30 determines whether or not to change the ratio of the second thrust of the main rotor 22 to the first thrust of the sub-rotor 12 based on flight conditions, weather information, etc. If the answer is "No", the process returns to step S10. On the other hand, if the answer is "Yes”, the control device 30 proceeds to step S18 and reduces or increases the second thrust of the main rotor 22, i.e., the output of the main thrust device. The control device 30 also increases or decreases the first thrust of the sub-rotor 12, i.e., the output of the attitude control device.
• step S22 the control device 30 estimates the current attitude angle of the multicopter 100.
• the control device 30 may obtain an estimated or measured value of the attitude angle from a sensor that estimates or measures the attitude angle.
• step S24 the control device 30 acquires the target attitude angle.
• the control device 30 may determine the target attitude angle based on flight conditions (task content) and weather information.
• step S26 the control device 30 obtains the amount of change in the attitude angle and determines whether the amount of change is equal to or greater than a predetermined value.
• the amount of change in the attitude angle is determined by the difference between the current estimated attitude angle and the target attitude angle. The larger this "amount of change,” the larger the amount of change in the attitude. If the result of the determination is "No,” the process returns to step S20. If the result is "Yes,” the process proceeds to step S28.
• step S30 the control device 30 reduces the output of the main thrust generating device and increases the output of the attitude control device. In other words, the control device 30 reduces the second thrust of the main rotor 22 and increases the first thrust of the sub-rotor 12.
• Processor 34 is one or more semiconductor integrated circuits, and is also called a central processing unit (CPU) or microprocessor. Processor 34 sequentially executes computer programs stored in ROM 35 to realize the above-mentioned processing. Processor 34 is broadly interpreted as a term including a CPU-equipped FPGA (Field Programmable Gate Array), GPU (Graphic Processor Unit), ASIC (Application Specific Integrated Circuit), or ASSP (Application Specific Standard Product).
• CPU CPU-equipped FPGA
• GPU Graphic Processor Unit
• ASIC Application Specific Integrated Circuit
• ASSP Application Specific Standard Product
• An unmanned aerial vehicle may also be equipped with multiple internal combustion engines with different power outputs and response speeds.
• an internal combustion engine with a relatively low power output and a relatively high response speed may constitute an "attitude control device”
• an internal combustion engine with a relatively high power output and a relatively low response speed may constitute a "main thrust generating device.”
• the controller is configured to control flight of the unmanned aerial vehicle in a plurality of flight modes;
• Item 12 A method for controlling an unmanned aerial vehicle as described in item 11, further comprising decreasing the second thrust and increasing the first thrust when changing the attitude of the unmanned aerial vehicle.
• Reference Signs List 2 Rotor (propeller), 3: Rotation drive device, 4: Aircraft body, 4a: Control device, 4b: Sensor group, 4c: Communication device, 5: Aircraft frame, 10: Multicopter, 12: Sub-rotor, 12a: Propeller, 12b: Propeller, 14: Motor, 16: ESC, 22: Main rotor, 52: Battery, 54: Battery management device

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Aviation & Aerospace Engineering (AREA)
• Mechanical Engineering (AREA)
• Remote Sensing (AREA)
• Control Of Position, Course, Altitude, Or Attitude Of Moving Bodies (AREA)

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Citations (2)

• 2022
  • 2022-12-27 JP JP2024567018A patent/JPWO2024142235A1/ja active Pending
  • 2022-12-27 WO PCT/JP2022/048167 patent/WO2024142235A1/ja active Application Filing

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