Propeller-equipped aircraft, its control method, and program

Abstract

To provide an aircraft body with a propeller, a control method thereof, and a program that can improve controllability even when a propeller cover is arranged to surround the radial outside of the propeller of the aircraft body with the propeller in order to improve quietness.SOLUTION: A drone 60 comprises: a controller 120 that determines a control amount for flight control according to an instruction from the outside; a drive unit 150 that rotates a propeller 610 according to an operation amount; an operation unit 140 that determines the operation amount according to the control amount; and a measurement unit 160 that detects that the drone 60 has come into a state corresponding to the instruction. In the drone 60, the propeller 610 is controlled on the basis of a differential response delay between a first response delay time calculated in a state with no propeller cover attached and a second response delay time calculated in a state with the propeller cover attached, where the response delay time is a differential between a first time point when the operation unit 140 determined the operation amount and a second time point when the measurement unit 160 performed the detection.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an aircraft with a propeller, a control method thereof, and a program, and particularly to an aircraft with a propeller capable of attaching and detaching a propeller cover, a control method thereof, and a program.

Background Art

[0002] Recently, the use of drones, which are one type of aircraft with a propeller, has been rapidly progressing, and the fields of their activities have been expanding. Until now, the driving sound, which was not a big problem because it was flown in the mountains or in less popular scenes, has become an issue as the opportunities to use it in urban areas and events have increased.

[0003] In Patent Document 1, a method of selecting an optimal shape around the wings of an unmanned aircraft having one or more propellers in view of the application, flight environment, controllability, and sound quality is proposed.

[0004] In Patent Document 2, a method of reducing the rotational speed of the propeller and enhancing the quietness by dividing the wings of the drone into a main wing and a sub-wing is proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, neither Patent Document 1 nor 2 mentions a configuration in which a cover is attached to the outer side in the radial direction of the propeller in order to reduce the noise generated by the propeller. In the case of a configuration in which a cover is attached to the outer side in the radial direction of the propeller, there is a risk that the controllability of the drone will deteriorate due to the cover.

[0007] The object of the present invention is to provide a propeller-equipped aircraft, a control method therefor, and a program that provide good controllability even when a propeller cover is positioned to surround the radially outer side of the propeller of the propeller-equipped aircraft in order to improve noise reduction. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a propeller-equipped aircraft that flies by driving a propeller, comprising: control means for determining a control amount for flight control in response to an external instruction; drive means for rotating the propeller in response to an operation amount; operation means for determining the operation amount in response to the control amount; detection means for detecting that the flight state of the propeller-equipped aircraft has become a state corresponding to the external instruction; a first time when the operation amount is transmitted from the operation means to the drive means; and the detection means detecting that the propeller-equipped aircraft has become a state corresponding to the external instruction. The system is characterized by comprising: a calculation means that calculates the difference in the second time when the state is detected as a response delay time; a setting means that sets the difference between a first response delay time calculated by the calculation means when the propeller cover is not arranged to surround the radially outer side of the propeller and a second response delay time calculated by the calculation means when the propeller cover is arranged to surround the radially outer side of the propeller as a response delay; and a control means that controls the propeller based on the set response delay so that the second response delay time approaches the first response delay time. [Effects of the Invention]

[0009] According to the present invention, controllability can be improved even when a propeller cover is positioned to surround the radially outer side of the propeller of an aircraft body equipped with a propeller in order to improve noise reduction. [Brief explanation of the drawing]

[0010] [Figure 1]This is a block diagram showing the configuration related to the control of a drone, which is a propeller-equipped aircraft according to Embodiment 1 of the present invention. [Figure 2] This is a flowchart of the response delay time setting process according to Embodiment 1 of the present invention. [Figure 3] This is a flowchart of the response delay time resetting process according to Embodiment 1 of the present invention. [Figure 4] This is a block diagram showing the configuration related to drone control according to Embodiment 2 of the present invention. [Figure 5] This is a flowchart of the manipulated variable adjustment process according to Embodiment 2 of the present invention. [Figure 6] This is an external view diagram of a drone. [Modes for carrying out the invention]

[0011] (Example 1) Referring to Figures 1 to 3 and Figure 6, a drone, which is a propeller-equipped aircraft according to Embodiment 1 of the present invention, will be described. Embodiment 1 describes a method to reduce the effect of the propeller cover by correcting the response delay caused by the propeller cover being attached compared to the state with the propeller cover removed.

[0012] Figure 6 is an external view of the drone 60. Figure 6(a) shows the drone without the propeller cover 620 (propeller cover-less state), and Figure 6(b) shows the drone with the propeller cover 620 attached (propeller cover-attached state).

[0013] As shown in Figure 6(a), the drone 60 comprises a main body 600 and propellers 610, and is remotely controlled by an external transmitter (remote control) 630. Also, as shown in Figure 6(b), the propellers 610 are configured to be fitted with propeller covers 620.

[0014] The aircraft body 600 has arms for holding each of the four pairs of propellers 610. The propellers 610 are a set of four pairs each attached to an arm of the aircraft body 600, and generate the buoyancy necessary to fly the drone 60. The propeller cover 620 is a cover that can be attached to the propeller 610 and is arranged to surround the radially outer side of the propeller 610 in order to reduce the noise generated by the propeller 610. In this embodiment, the propeller cover 620 has a configuration in which the width in the axial direction of the propeller 610 is larger than that of the propeller 610, so the effect of improving quietness is high. Also, in this embodiment, the propeller cover 620 is arranged to surround the entire circumference of the radially outer side of the propeller 610, so the effect of improving quietness is high, but openings, cutouts, etc. may be provided in part. The transmitter 630 is a transmitter that transmits an instruction for the operator to remotely control the drone 60 to the drone 60. The operator here does not have to be a person and may be a computer provided separately for automatic control of the drone.

[0015] FIG. 1 is a block diagram showing a configuration related to the control of the drone 60 of FIG. 6 according to this embodiment.

[0016] The drone 60 includes a controller 120, an operation unit 140, a drive unit 150, a measurement unit 16, a calculation and storage unit 170, and an attitude sensor 190 inside the aircraft body 600. In this embodiment, one or more processors or circuits are provided inside the aircraft body 600, and by reading and executing a program stored in the ROM, it functions as at least one of the controller 120, the operation unit 140, the drive unit 150, and the calculation and storage unit 170.

[0017] The controller 120 (control means) includes a PID controller that calculates the control amount necessary for flight control of the drone 60 according to an instruction from the transmitter 630, and a compensator 180 (compensation means) that compensates for the response delay described later.

[0018] The operation unit 140 (operation means) generates (determines) an operation amount for driving the drive unit 150 based on the control amount calculated by the controller 120, and transmits it to the drive unit 150. Further, the operation unit 140 transmits the time when the operation amount is generated to the calculation and storage unit 170 as the operation start time (first time).

[0019] The drive unit 150 (drive means) controls the flight of the drone 60 by rotating the propeller 610 (determining the number of revolutions per second of the propeller 610) based on the operation amount transmitted from the operation unit 140.

[0020] The measurement unit 160 (detection means) is a sensor that grasps the flight state of the drone 60. Note that the type of the sensor is not limited as long as the flight state of the drone 60 can be grasped, and examples thereof include sensors such as an acceleration sensor, a gyro sensor, and GPS. Further, the measurement unit 160 may be shared with the attitude sensor 190. In the present embodiment, an acceleration sensor is used for the measurement unit 160. Further, the measurement unit 160 detects that the drone 60 has become a state corresponding to the instruction from the prop 630 from the grasped flight state, and transmits the detected time to the calculation and storage unit 170 as the response time (second time).

[0021] The calculation and storage unit 170 (calculation means) calculates the difference between the operation start time transmitted from the operation unit 140 and the response time transmitted from the measurement unit 160 as the time (response delay time) from when the instruction is received from the prop 630 until the drone 60 responds to the instruction.

[0022] Further, the calculation and storage unit 170 stores the calculated response delay time in a memory or the like. The attitude sensor 190 is an attitude sensor such as an acceleration sensor or a gyro sensor that detects the attitude of the drone 60 and is necessary for flight control of the drone 60. Note that the technology of flight control of the drone by the attitude sensor is a general technology, and thus the details thereof are not described here.

[0023] FIG. 2 is a flowchart of the response delay time setting process according to the present embodiment.

[0024] This process is performed by one or more processors or circuits located inside the aircraft body 600 reading a program stored in ROM. Furthermore, the process shown in Figure 2 is performed in windless conditions or similar conditions.

[0025] First, in step S201, the calculation and storage unit 170 calculates the response delay time (first response delay time) of the drone 60, assuming that the propeller cover 620 is absent, as shown in Figure 6(a). Specifically, when a takeoff operation instruction is received from the transmitter 630, the operation unit 140 generates an operation variable. At this time, the calculation and storage unit 170 obtains the operation start time from the operation unit 140. Subsequently, when the measurement unit 160 detects that the takeoff operation has started based on this operation variable, the calculation and storage unit 170 obtains the detected time (response time) from the measurement unit 160. From the obtained operation start time and response time, the calculation and storage unit 170 calculates the response delay time for the takeoff operation instruction from the transmitter 630.

[0026] In step S202, the calculation and storage unit 170 stores the response delay time measured in step S201 as a first measured value in memory or the like.

[0027] In step S203, the propeller cover 620 is attached as shown in Figure 6(b) in order to measure the response delay time of the drone 60 with the propeller cover 620 attached. The operation of attaching the propeller cover 620 may be performed manually by the operator, or it may be performed automatically if automatic attachment and detachment of the propeller cover 620 is possible.

[0028] Next, in step S204, the calculation and storage unit 170 calculates the response delay time (second response delay time) of the drone 60 with the propeller cover 620 attached. The specific measurement method is the same as in step S201 and will therefore be omitted. If the operator manually attaches the propeller cover 620 in step S203, the process should proceed to step S204 according to the operator's instructions after the attachment operation is completed.

[0029] In step S205, the calculation and storage unit 170 stores the response delay time calculated in step S204 as a second measured value in memory.

[0030] In step S206, the calculation and storage unit 170 calculates the difference between the first and second measured values ​​stored in steps S202 and S205. Then, the calculation and storage unit 170 (setting means) sets this calculated difference as the response delay obtained by measurement in the compensator 180 of the controller 120. The controller 120 controls the rotation speed of the propeller 610 so that the second measured value approaches the first measured value by compensating the set response delay in the compensator 180, and then terminates this process.

[0031] According to the process shown in Figure 2, when the drone 60 is flown with the propeller cover 620 attached, the response delay of the drone 60 can be compensated by the compensator 180.

[0032] Furthermore, using the flowchart in Figure 3, a useful method for compensating for response delay when flying the drone 60 with the propeller cover 620 attached in an environment different from the environment in which the second measurement value was taken will be explained. Here, the environment different from the environment in which the second measurement value was taken specifically refers to the second measurement time (second measurement period) that does not overlap with the first measurement time (first measurement period) in which the second measurement value was taken.

[0033] Figure 3 is a flowchart of the response delay time resetting process according to this embodiment.

[0034] This process, similar to the process shown in Figure 2, is executed by one or more processors or circuits located inside the main body 600 reading a program stored in ROM.

[0035] First, in step S301, the calculation and storage unit 170 is configured with the propeller cover 620 attached, as shown in Figure 6(b), and measures (recalculates) the response delay time of the drone 60 (recalculated second response delay time) at the second measurement time. The specific measurement method is the same as in step S201 and will therefore be omitted.

[0036] In step S302, the calculation and storage unit 170 stores the response delay time measured in step S301 in memory as a third measured value.

[0037] In step S303, the calculation and storage unit 170 compares the second measurement value stored in step S205 with the third measurement value stored in step S302. If the third measurement value is larger (YES in step S303), the process proceeds to step S304. Otherwise (NO in step S303), the compensator 180 performs compensation with the response delay already set in step S206 and terminates this process.

[0038] In step S304, the calculation and storage unit 170 calculates the difference between the first measurement value stored in memory in step S202 and the third measurement value stored in memory in step S302. Then, the calculation and storage unit 170 (setting means) resets the compensator 180 of the controller 120 with this calculated difference as the response delay obtained by measurement. The controller 120 controls the rotation speed of the propeller 610 so that the third measurement value approaches the first measurement value by compensating for the reset response delay with the compensator 180, and then terminates this process.

[0039] According to the process shown in Figure 3, even if the environment in which the drone 60 is flown with the propeller cover 620 attached changes, it becomes possible to compensate for the response delay of the drone 60.

[0040] In summary, the response delay time of the drone 60 was measured before and after removing the propeller cover 620, and the difference in the measured response delay time was used as the response delay, which was then compensated for by the compensator 180. This reduces the impact of the response delay caused by the propeller cover 620.

[0041] (Example 2) Referring to Figures 4 and 5, a drone, which is a propeller-equipped aircraft according to Embodiment 2 of the present invention, will be described. Embodiment 2 describes a method to reduce the effects of external disturbances such as wind by comparing the current flow rate during flight with a pre-stored reference flow rate for each operation type, and calculating the control amount to be transmitted to the control unit 140 based on the result.

[0042] In Example 2, the same numbering will be used for components identical to those in Example 1, and redundant explanations will be omitted.

[0043] Figure 4 is a block diagram showing the configuration related to the control of the drone 60 in Figure 6 according to this embodiment.

[0044] The drone 60 includes a controller 420, an operation unit 440, a drive unit 450, a flow rate measuring unit 460, a calculation / storage unit 470, a manipulated variable correction unit 480, and an attitude sensor 490 inside the aircraft body 600. In this embodiment, one or more processors or circuits are provided inside the aircraft body 600, and they function as at least one of the controller 420, operation unit 440, drive unit 450, and calculation / storage unit 470 by reading and executing a program stored in ROM.

[0045] The controller 420 (control means) includes a PID controller that calculates the control quantities necessary to control the flight of the drone 60 in response to instructions from the transmitter 630. The controller 420 calculates the control quantities sequentially for each type of operation necessary to execute the instructions from the transmitter 630. The controller 420 also associates each calculated control quantity with the instruction content flag (identification information) included in the instructions from the transmitter 630 and its operation type, and transmits it to the operation unit 440. The instruction content flag indicates whether it is an instruction for initial measurement (an instruction at the reference time described later) (OFF) or an instruction for normal flight (an instruction at the measurement time described later) (ON).

[0046] The operation unit 440 (operating means) generates an operation quantity for driving the drive unit 450 based on the control quantity transmitted from the controller 420 and transmits it to the drive unit 150. At this time, the operation unit 140 transmits the instruction content flag and operation type associated with the control quantity transmitted from the controller 420 to the calculation and storage unit 470 as the current instruction content flag and current operation type.

[0047] The drive unit 450 (driving means) controls the flight of the drone 60 by rotating the propeller 610 (determining the rotation speed of the propeller 610 per second) based on the input transmitted from the control unit 140.

[0048] The flow rate measuring unit 460 (flow rate measuring means) measures the airflow rate generated by the propeller 610 of the drone 60, and when the flow rate measurement is complete, it notifies the calculation / storage unit 470 of the measured flow rate. If the current instruction content flag is OFF, the calculation / storage unit 470 stores the flow rate notified by the flow rate measuring unit 460 in memory, linked to the reference flow rate for the current operation type. On the other hand, if the current instruction content flag is ON, the calculation / storage unit 470 transmits the flow rate notified by the flow rate measuring unit 460 as the current flow rate, linked to the current operation type, to the operation amount correction unit 480. The flow rate measuring unit 460 is not limited to the type of sensor as long as the lift of the drone 60 is known, but examples of sensors include flow rate sensors and flow velocity sensors. The flow rate measured by the flow rate measuring unit 460 may be the flow rate of one propeller 610 or multiple flow rates of propeller 610.

[0049] The manipulated variable correction unit 480 (manipulated variable correction means) corrects the manipulated variable for the current operation type output by the operation unit 440 based on the difference between the current flow rate and the reference flow rate, which are associated with the current operation type. The current operation type, the current flow rate, and the reference flow rate associated with it are transmitted from the calculation / storage unit 470 to the manipulated variable correction unit 480.

[0050] The attitude sensor 490 is an attitude sensor necessary for controlling the flight of the drone 60, as it detects the drone's attitude. Note that the technology of controlling drone flight using attitude sensors is a common technique, so its details will not be explained here.

[0051] Figure 5 is a flowchart of the controllable variable adjustment process according to this embodiment. This process describes a method of adjusting the controllable variable by comparing the reference flow rate with the current flow rate during normal flight and correcting the controllable variable based on the difference.

[0052] This process, similar to the processes shown in Figures 2 and 3, is executed by one or more processors or circuits located inside the main body 600 reading a program stored in ROM.

[0053] First, in step S501, the flow rate measuring unit 460 measures the standard flow rate for each operation type with the propeller cover 620 attached, as shown in Figure 6(b), during a windless standard time (standard period). Specifically, when an instruction for an initial measurement takeoff operation is received from the transmitter 630, the operation unit 440 sequentially generates operation quantities for the operations required for the takeoff operation. At this time, the calculation and storage unit 470 obtains the operation type and an instruction content flag indicating that it is an instruction for initial measurement (OFF) from the operation unit 440. Subsequently, the flow rate measuring unit 460 measures the flow rate of air generated by the propeller 610 of the drone 60, which rotates based on this operation quantity. At this time, the calculation and storage unit 470 obtains the measured flow rate from the flow rate measuring unit 460. Based on the current instruction content flag (OFF) and the current operation type, the calculation and storage unit 470 stores the flow rate measured by the flow rate measuring unit 460 in memory as the standard flow rate for the current operation type. Here, the instructions from the transmitter 630 performed in step S501 are defined as the takeoff operation, but any flight pattern that covers the operations necessary for normal flight does not necessarily have to be a takeoff operation. Also, in this embodiment, the reference time is defined as the time in windless conditions, but it is not limited to this, as long as it is a similar condition.

[0054] In step S502, the calculation and storage unit 470 sequentially stores the reference flow rates for each operation type measured in step S501 into its memory.

[0055] In step S503, the flow rate measuring unit 460 starts normal flight during a measurement time (measurement period) that does not overlap with the reference time and measures the current flow rate. Specifically, when an operation instruction is received from the transmitter 630 during the normal flight of the drone 60, the operation unit 440 generates the operation amount required for that operation. At this time, the calculation and storage unit 470 obtains from the operation unit 440 the operation type and an instruction content flag indicating that it is an instruction for normal flight (ON). Subsequently, the flow rate measuring unit 460 measures the flow rate of air generated by the propeller 610 of the drone 60, which rotates based on this operation amount. At this time, the calculation and storage unit 470 obtains the measured flow rate from the flow rate measuring unit 460. Based on the current instruction content flag (ON) and the current operation type, the calculation and storage unit 470 transmits the flow rate measured by the flow rate measuring unit 460 to the operation amount correction unit 480 as the current flow rate for the current operation type. Furthermore, if the instruction content flag is also transmitted from the operation unit 440 to the flow rate measurement unit 460, the flow rate measurement unit 460 may transmit the current flow rate to the operation amount correction unit 480 if the current instruction content flag is ON.

[0056] In step S504, the manipulated variable correction unit 480 corrects (adjusts) the manipulated variable so that the current flow rate approaches the reference flow rate for the current operation type, and then terminates this process.

[0057] In summary, the flow rate for each operation type is measured in windless conditions with the propeller cover 620 attached, and this is used as the reference flow rate. The control amount is then adjusted so that the flow rate for each operation type during normal flight approaches the reference flow rate. This reduces the impact of external disturbances such as wind on the control of the drone 60 during normal flight.

[0058] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist.

[0059] (Other embodiments) In this embodiment, the system can also be implemented by supplying a program that implements one or more functions to a computer of a system or device via a network or storage medium, and the system control unit of that system or device reads and executes the program. The system control unit has one or more processors or circuits and may include a plurality of separate system control units or a network of a plurality of separate processors or circuits in order to read and execute executable instructions.

[0060] A processor or circuit may include a central processing unit (CPU), a microprocessing unit (MPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). Alternatively, a processor or circuit may include a digital signal processor (DSP), a dataflow processor (DFP), or a neural processing unit (NPU).

[0061] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist. [Explanation of symbols]

[0062] 120,420 controllers 140,440 Operation section 150,450 Drive unit 160 Measuring section 170 Calculation / memory section 460 Flow measurement section 470 Calculation and storage section 180 Compensator 480 Operation amount correction section 190,490 posture sensors 60 Drones 600 aircraft body 610 Propeller 620 Propeller Cover

Claims

1. A propeller-equipped aircraft that flies by driving a propeller, A control means for determining control quantities for flight control in response to external instructions, A drive means for rotating the propeller according to the amount of operation, An operating means for determining the manipulated amount according to the controlled amount, A detection means for detecting that the flight state of the propeller-equipped aircraft has become a state corresponding to the external instruction, A calculation means calculates the difference between a first time when the manipulated amount is transmitted from the operating means to the driving means and a second time when the detection means detects that the propeller-equipped aircraft has entered a state that responds to the external instruction, as the response delay time. A setting means sets the difference between a first response delay time calculated by the calculation means when the propeller cover is not positioned to surround the radially outer side of the propeller and a second response delay time calculated by the calculation means when the propeller cover is positioned to surround the radially outer side of the propeller as the response delay. A propeller-equipped aircraft comprising: control means for controlling the propeller such that the second response delay time approaches the first response delay time based on the set response delay.

2. The propeller-equipped aircraft body according to claim 1, characterized in that the control means further comprises a compensation means for compensating the set response delay.

3. The calculation means recalculates the second response delay time at a second measurement time that does not overlap with the first measurement time at which the second response delay time was calculated, with the propeller cover positioned to surround the radially outer side of the propeller. If the second response delay time recalculated by the calculation means during the second measurement time is greater than the second response delay time calculated by the calculation means during the first measurement time, the setting means resets the response delay to the difference between the first response delay time and the recalculated second response delay time. The propeller-equipped aircraft body according to claim 1 or 2, characterized in that the control means controls the propeller based on the reset response delay so that the reset second response delay time approaches the first response delay time.

4. A method for controlling a propeller-equipped aircraft that flies by driving its propellers, The aforementioned propeller-equipped aircraft body is A control means for determining control quantities for flight control in response to external instructions, A drive means for rotating the propeller according to the amount of operation, An operating means for determining the manipulated amount according to the controlled amount, The system includes a detection means for detecting when the flight state of the propeller-equipped aircraft has become a state corresponding to the external instruction, A calculation step in which the difference between a first time when the manipulated amount is transmitted from the operating means to the driving means and a second time when the detection means detects that the propeller-equipped aircraft has entered a state that responds to the external instruction is calculated as the response delay time, A setting step in which the difference between a first response delay time calculated by the calculation step when the propeller cover is not positioned to surround the radially outer side of the propeller and a second response delay time calculated by the calculation step when the propeller cover is positioned to surround the radially outer side of the propeller is set as the response delay, A control method characterized by comprising a control step of controlling the propeller based on the set response delay so that the second response delay time approaches the first response delay time.

5. A computer-executable program that causes a computer to function as each step of a propeller-driven aircraft according to any one of claims 1 to 3.

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