JP2019064581A - Rotor craft - Google Patents

Abstract

To enable flexible adjustment of the steering stability of a rotor craft against disturbances such as an updraft and the flight efficiency thereof.SOLUTION: The problem is solved by a rotor craft comprising a plurality of horizontal rotors, in which the plurality of horizontal rotors include large diameter propellers and small diameter propellers, which have different diameters, or large pitch propellers and small pitch propellers, which have different pitch angles. In the case where the large diameter propellers and the large pitch propellers are referred to as large lift propellers and the small diameter propellers and the small pitch propellers are referred to as small lift propellers, the large lift propellers and the small lift propellers are fixed pitch propellers whose lift is adjusted by controlling the rotation speed, and the small lift propellers are driven when the rotation speed of the large lift propellers falls below a predetermined threshold. The problem is solved also by a rotor craft in which, during flight, the rotation speed of large lift propellers can be lowered to a rotation speed or less where the gyro effect or lift thereof is lost.SELECTED DRAWING: Figure 1

Description

  The present invention relates to the steering stability of a rotorcraft.

  The following Patent Document 1 discloses a concept in which, when the main rotor of a helicopter breaks down, a separately provided auxiliary rotor attempts to softly land it.

JP-A-4-274995

  Rotorcraft using propellers with a fixed pitch angle (fixed pitch propellers) usually adjusts the lift of these propellers by controlling the rotational speed of each propeller (herein the same as the rotational speed in the present application; the same shall apply hereinafter). Do. Such rotary-wing aircraft maintain its altitude by lowering the number of revolutions of the propeller when the aircraft is pushed up by the updraft in flight. Naturally, when a strong updraft is hit, it is necessary to reduce the number of revolutions accordingly. On the other hand, in order for the propeller to exhibit its original function, it is necessary to have a rotational speed at which sufficient lift and gyro effects can be obtained. When the propeller speed is lowered beyond its lower limit, the propeller loses control of the airframe and the rotorcraft becomes unsteerable.

  In view of the above problems, it is an object of the present invention to improve the steering stability of a rotary wing aircraft against disturbances such as updraft.

  In order to solve the above problems, the rotary wing aircraft of the present invention includes a plurality of horizontal rotary wings, and the plurality of horizontal rotary wings are large diameter propellers and small diameter propellers which are propellers having different diameters, or pitch angles are different. The large diameter propeller and the large pitch propeller are referred to as a large lift propeller and the small diameter propeller and the small pitch propeller are referred to as a small lift propeller. The lift propeller and the small lift propeller are fixed pitch propellers whose lift is adjusted by controlling the rotational speed, and the small lift propeller is driven when the rotational speed of the large lift propeller falls below a predetermined threshold. It is characterized by being.

  If you want to use a small diameter propeller (small diameter propeller) to obtain lift equivalent to that of a larger diameter propeller (large diameter propeller), the small diameter propeller needs to rotate faster than the large diameter propeller . That is, when trying to obtain a certain lift, if a large diameter propeller falls into a rotational speed at which the gyro effect or lift is lost, a small diameter propeller may sometimes obtain a sufficient rotational speed. In this sense, it can be said that the small diameter propeller is more resistant to disturbances such as updraft than the large diameter propeller. On the other hand, rotating the large diameter propeller at low speed is better in terms of propeller efficiency and energy efficiency than rotating the small diameter propeller at high speed. This relationship also holds between a propeller with a small pitch angle (small pitch propeller) and a propeller with a larger pitch angle (large pitch propeller). By providing both of these large diameter propellers and large pitch propellers (large lift propellers) and small diameter propellers and small pitch propellers (small lift propellers), it is possible to flexibly adjust the balance between resistance to disturbance and efficiency. It becomes. Further, by driving the low lift propeller when the rotational speed of the high lift propeller falls below a predetermined threshold value, it is possible to make the resistance to disturbance and the energy efficiency be more ideally achieved.

  Furthermore, in order to solve the above problems, the rotary wing aircraft of the present invention is a rotary wing aircraft provided with a plurality of horizontal rotary wings, and the plurality of horizontal rotary wings are large diameter propellers and small diameter propellers having different diameters. A large pitch propeller and a small pitch propeller that are propellers or propellers having different pitch angles are included, and the large diameter propeller and the large pitch propeller are referred to as a large lift propeller, and the small diameter propeller and the small pitch propeller are small lift When the propellers are referred to, the high lift propellers and the small lift propellers are fixed pitch propellers whose lifts are adjusted by controlling their rotational speeds, and the rotational effects of the high lift propellers during flight are controlled by the gyro effect or It is characterized in that it is possible to reduce the number of revolutions below which the lift is lost.

  Usually, the propellers of rotary-wing aircraft need to maintain the number of revolutions without losing the controllability of the fuselage. In the present invention, the rotational speed of the high lift propeller can be reduced to a level at which the gyro effect and lift are lost, and the flight with only the low lift propeller is enabled, thereby significantly lowering the lower limit of lift of the rotary wing aircraft. It becomes possible.

  Further, it is preferable that the rotary wing aircraft of the present invention has a plurality of the low lift propellers, and the plurality of low lift propellers are disposed at positions where the horizontal plane of the fuselage can be maintained with only the low lift propellers. .

  By making it possible to maintain the level of the fuselage with only the low lift propeller, even if the gyro effect or lift of the high lift propeller is lost, it is possible to escape the situation or softly land the fuselage with the low lift propeller. Here, "maintaining the level" means that the tilt of the vehicle can be controlled, and it is not necessary to be able to maintain the orientation (orientation) of the vehicle or the altitude.

  In the rotary wing aircraft of the present invention, a plurality of sets of the high lift propeller and the small lift propeller are provided in a one-to-one combination, and the high lift propeller and the small lift propeller of each set are coaxially arranged It is good also as a composition.

  By coaxially arranging the high lift propellers and the low lift propellers of each set, for example, the number of arms supporting them can be reduced, and the parts efficiency and the structural efficiency of the airframe can be enhanced.

  Further, in this case, it is preferable that the high lift propellers and the low lift propellers of each set can be driven simultaneously, and the low lift propellers are disposed on the exhaust side of the high lift propellers that make up the pair.

  When the horizontal rotary wing receives a cross wind, the air flow may be separated from the propeller and the lift may be reduced. At this time, if the rotational speed is increased to compensate for the lost lift, the separation of the air flow is aggravated. This phenomenon causes the attitude of the airframe and noise. The low lift propeller of this configuration is disposed on the exhaust side of the high lift propeller, and is covered by the downwash when the high lift propeller is driven, so it is less susceptible to crosswinds. Then, when the lift of the large lift propeller decreases, the small lift propeller is driven to compensate for this, so separation of the air flow of the large lift propeller is suppressed. This makes it possible to further improve the resistance of the rotorcraft to disturbances.

  In the rotary wing aircraft of the present invention, the sum of maximum lifts of the low lift propellers may be smaller than the weight of the rotary wing aircraft.

  Even if the flight height can not be maintained with the lift of the small lift propeller alone, if the level of the airframe can be maintained with these small lift propellers, even if the gyro effect or lift of the large lift propeller is lost, only the small lift propeller Makes it possible to softly land the aircraft.

  In the rotary-wing aircraft of the present invention, it is preferable that the sum of the maximum lifts of the high lift propellers be larger than the sum of the maximum lifts of the small lift propellers.

  The ability to use a high lift propeller as a main thrust source during normal flight rather than an auxiliary thrust source can increase energy efficiency during flight.

  Also, the rotary wing aircraft of the present invention may be an unmanned aerial vehicle.

  There are many lightweight aircrafts in unmanned aerial vehicles equipped with a plurality of horizontal rotary wings, and there is a tendency that the number of revolutions of the propeller tends to reach the lower limit compared to manned aircraft. By applying the present invention to such an unmanned aerial vehicle, its steering stability can be significantly improved.

  As described above, according to the rotary-wing aircraft of the present invention, it is possible to flexibly adjust the steering stability against the disturbance such as the rising air flow and the flight efficiency thereof.

It is a perspective view which shows the external appearance of the multicopter concerning 1st Embodiment. It is a block diagram showing functional composition of a multicopter of a 1st embodiment. It is a schematic diagram explaining the steering stability improvement effect by a small diameter propeller (under normal environment). It is a schematic diagram explaining the steering stability improvement effect by a small diameter propeller (at the time of updraft generation | occurrence | production). It is a perspective view which shows the external appearance of the multicopter concerning 2nd Embodiment. It is a block diagram which shows the function structure of the multicopter of 2nd Embodiment. It is a schematic diagram which shows the lift required for hovering before agrochemical spraying. It is a schematic diagram which shows the lift required for hovering after agrochemical spraying.

  Hereinafter, embodiments of the present invention will be described. The embodiments described below are all examples of unmanned rotary wing aircraft flying with a plurality of horizontal rotary wings. The “horizontal rotary wing” in the present invention means a rotary wing in which the axial direction of the rotation axis extends vertically and the plane direction of the rotary surface is horizontal.

First Embodiment
(Configuration outline)
FIG. 1 is a perspective view showing the appearance of a multicopter 10 according to the present embodiment (hereinafter, also referred to as “this example”). The multicopter 10 of this example is an aircraft whose purpose is to perform aerial photography.

  The multicopter 10 mainly includes a shell 11 which is a case body for housing a control system, six arms 12 made of cylindrical pipe members, a rotor 60 having a large diameter propeller 61, and a rotor 70 having a small diameter propeller 71, And a camera 91 mounted on the posture stabilization device. The large diameter propeller 61 is a type of the large lift propeller of the present invention, and the small diameter propeller 71 is a type of the small lift propeller of the present invention.

  The large diameter propeller 61 and the small diameter propeller 71 are propellers having different diameters. In this example, a propeller having a diameter about half that of the large diameter propeller 61 is employed as the small diameter propeller 71. Further, the large diameter propeller 61 and the small diameter propeller 71 are fixed pitch propellers whose lift is adjusted by controlling the rotational speed. The multicopter 10 of this example can perform all flight operations with only the large diameter propeller 61 or only the small diameter propeller 71.

  The arms 12 of the multicopter 10 radially extend from the shell 11 in the horizontal direction, and they are equally spaced around the shell 11 along the circumferential direction thereof. The large diameter propeller 61 (rotor 60) and the small diameter propeller 71 (rotor 70) are disposed at the tip of each arm 12. The large diameter propellers 61 and the small diameter propellers 71 are combined one by one, and the large diameter propellers 61 and the small diameter propellers 71 of each set are coaxially arranged. Further, in the present embodiment, each small diameter propeller 71 is disposed on the exhaust side of the large diameter propeller 61 that is the pair. In this example, two propellers, the large diameter propeller 61 (rotor 60) and the small diameter propeller 71 (rotor 70), are supported by one arm 12 so that the number of arms 12 supporting these can be reduced. The parts efficiency and structural efficiency of the fuselage are enhanced.

(Functional configuration)
FIG. 2 is a block diagram showing the functional configuration of the multicopter 10 of this embodiment. The functions of the multicopter 10 mainly include a flight controller FC as a control unit, a rotor 60 for driving the large diameter propeller 61, a rotor 70 for driving the small diameter propeller 71, and a brushless motor (not shown) ), A receiver 42 for receiving steering signals from the driver (transmitter 41), a camera 91 as an external device, and a battery 80 for supplying power thereto. It is done.

  The flight controller FC includes a controller 20 which is a microcontroller. The control device 20 controls the number of rotations of each of the rotors 60 and 70 via the ESC 50 and a CPU 22 which is a central processing unit, a memory 22 including a storage device such as a RAM and a ROM / flash memory, and PWM (Pulse Width Modulation: Pulse width modulation) controller 23 is provided.

  The flight controller FC further includes a flight control sensor group S including an IMU 31 (Inertial Measurement Unit: inertial measurement device), a GPS receiver 32, an altitude sensor 33, and an electronic compass 34, which are connected to the control device 20. It is done.

  The IMU 31 is a sensor that detects the tilt of the airframe of the multicopter 10, and is mainly composed of a 3-axis acceleration sensor and a 3-axis angular velocity sensor. A barometric pressure sensor is used for the height sensor 32 in this example. The altitude sensor 32 calculates the altitude above sea level (altitude) of the multicopter 10 from the detected atmospheric pressure altitude. In addition to this, as a mode of the altitude sensor 33, for example, it is conceivable to direct a distance measuring sensor using a laser, an infrared ray, an ultrasonic wave or the like to the ground surface to acquire the ground altitude. A three-axis geomagnetic sensor is used for the electronic compass 33 in this example. The electronic compass 33 detects the azimuth of the nose of the multicopter 10. The GPS receiver 34 is precisely a receiver of a navigation satellite system (NSS). The GPS receiver 34 acquires current longitude and latitude values and time information from a Global Navigation Satellite System (GNSS) or a Regional Navigational Satellite System (RNSS). It is possible that the flight controller FC can obtain the position information of its own aircraft including the latitude and longitude in flight, altitude, and the azimuth angle of the nose as well as the tilt and rotation of the aircraft by these flight control sensor groups S. It is done.

  Although the flight control sensor group S of this example is configured for outdoor use, the multicopter 10 may fly indoors. For example, beacons for transmitting radio signals are arranged at predetermined intervals in a facility, and the relative distance between the multicopter 10 and each beacon is measured from the radio wave strength of the signals received from these beacons, and the multicopter in the facility It is conceivable to identify ten positions. Alternatively, it is also possible to mount a camera separately on the multicopter 10, detect a characteristic location in the facility by image recognition from the surrounding image captured by the camera, and specify the position in the facility based on this. Similarly, a distance measuring sensor using a laser, infrared rays, ultrasonic waves, etc. is separately mounted, and the distance between the floor (or ceiling) or wall in the facility and the multicopter 10 is measured, and the multi It is also possible to specify the position of the copter 10.

  The controller 20 has a flight control program FS which is a program for controlling the attitude of the multicopter 10 during flight and basic flight operations. The flight control program FS adjusts the number of revolutions of the individual rotors 60 and 70 based on the information acquired from the flight control sensor group S, and controls the flight operation of the multicopter 10 while correcting the attitude and position disturbance of the vehicle. Do.

  The control device 20 further includes an autonomous flight program AP which is a program for causing the multicopter 10 to fly autonomously. A flight plan FP is registered in the memory 22 of the control device 20. The flight plan FP is a parameter in which the latitude and longitude of the destination and transit point of the multicopter 10, the altitude and the speed during flight, etc. are designated. The autonomous flight program AP can make the multicopter 10 fly autonomously according to the flight plan FP, with an instruction from the transmitter 41, a predetermined time, etc. as a start condition. Such an autonomous flight function is called "autopilot" in this example.

  Thus, the multicopter 10 of the present example is an unmanned aerial vehicle equipped with advanced flight control functions. However, the rotary wing aircraft of the present invention is not limited to the form of multicopter 10. For example, an aircraft with some sensors omitted from flight control sensor group S, or an autopilot function, and can fly only by manual operation. Aircraft can also be used. The rotary-wing aircraft of the present invention also includes a VTOL (Vertical Take-Off and Landing) in which take-off and landing are performed only by horizontal rotary wings. Furthermore, the rotary-wing aircraft of the present invention is not limited to a drone, and may be a manned aircraft manually operated by an onboard pilot.

(Propeller configuration)
As mentioned above, the multicopter 10 has both the large diameter propeller 61 and the small diameter propeller 71 as its horizontal rotary vane.

  In order to obtain lift equivalent to that of the large diameter propeller 61 by the small diameter propeller 71, the small diameter propeller 71 needs to be rotated at a higher speed than the large diameter propeller 61. That is, when trying to obtain a certain lift, if the large diameter propeller 61 falls into the rotational speed where the gyro effect or lift is lost, the small diameter propeller 71 may obtain the rotational speed necessary for steering. is there. On the other hand, rotating the large diameter propeller 61 at low speed is superior to rotating the small diameter propeller 71 at high speed in terms of propeller efficiency and energy efficiency. The multicopter 10 is provided with both the large diameter propeller 61 and the small diameter propeller 71, so that it is possible to adjust the balance between resistance to disturbance and efficiency.

  Here, the ratio of the diameters of the large diameter propeller 61 and the small diameter propeller 71 is not specifically limited. The large diameter propeller and the small diameter propeller according to the present invention have a smaller diameter smaller than the diameter of the large diameter propeller and a lift smaller than the lift at the lower limit of the rotational speed at which the large diameter propeller can control the propeller. It is sufficient that the propellers can be supplied while maintaining the control function of the airframe (while ensuring the required number of revolutions). Usually, this relationship holds between two propellers of different diameters. For example, whether the flight environment is indoor or outdoor, or indoor if it is an airless environment or an environment where special air flow such as a tunnel is generated, as a factor that influences the ratio of diameters of these large diameter propellers and small diameter propellers. Even in the open air, it may be an open place or a place along a wall or a mountain surface, and further, energy efficiency required, minimum lift required for attitude control of the airframe, and the like may be considered.

  Providing both a large diameter propeller and a small diameter propeller means that the width of the stably obtained lift is extended. Naturally, the smaller the difference in diameter between the large diameter propeller and the small diameter propeller, the smaller the width of the extended lift, and the larger the difference in diameter, the larger the width of the extended lift. The ratio of diameters of the large diameter propeller and the small diameter propeller may be set to an optimum ratio according to the flight environment, in consideration of the balance between the resistance to disturbance such as rising air flow and the efficiency.

  The flight control program FS of this example basically causes the multicopter 10 to fly with only the large diameter propeller 61 (rotor 60). Then, the flight control program FS sets the rotation speed of the large diameter propeller 61 as a threshold value to the rotation speed where the gyro effect or lift of the large diameter propeller 61 may be lost, taking into consideration the margin for securing safety. The small diameter propeller 71 is driven when the number falls below this threshold. That is, the large diameter propeller 61 and the small diameter propeller 71 are selectively used according to the size of the lift required at that time. Thereby, the resistance to disturbance and the efficiency are more ideally balanced.

  On the other hand, as described above, the large diameter propeller 61 and the small diameter propeller 71 of this example are combined one by one, and the large diameter propeller 61 and the small diameter propeller 71 of each set are coaxially arranged. And each small diameter propeller 71 is arranged on the exhaust side of the large diameter propeller 61 which becomes the pair.

  When the horizontal rotary wing receives a cross wind, the air flow may be separated from the propeller and the lift may be reduced. At this time, if the rotational speed is increased to compensate for the lost lift, the separation of the air flow is aggravated. This phenomenon causes the attitude of the airframe and noise. The small diameter propeller 71 of this example is disposed on the exhaust side of the large diameter propeller 61 and is always covered with the downwash of the large diameter propeller 61. Therefore, the small diameter propeller 71 is unlikely to be affected by the cross wind.

  That is, when the configuration of the multicopter 10 is changed so as to always drive both the small diameter propeller 71 and the large diameter propeller 61, when the air flow is separated from the large diameter propeller 61, the lost lift is reduced to the small diameter propeller 71. It is possible to make up for it immediately. Thereby, the separation of the air flow of the large diameter propeller 61 is suppressed, and the resistance to the disturbance of the multicopter 10 can be further enhanced.

  FIGS. 3 and 4 are schematic views illustrating the principle of improving the steering stability of the multicopter 10 by the small diameter propeller 71. FIG. Hereinafter, description will be made with reference to these figures. 3 and 4 are schematic diagrams in which details are simplified by emphasizing only the main points for convenience of explanation, and they do not exactly correspond to the actual state.

  The vertical axes in FIG. 3 and FIG. 4 show the magnitude of the lift at a level of 0 to 9. In the following description, the loss of the propeller function means that the propeller's gyro effect and lift are lost due to the decrease in propeller rotation speed, that is, the control function of the propeller by the propeller is lost. There is. The lift 0 is a state in which no lift is generated, and the lift 9 is a state in which the largest lift is generated. In this example, the width of the lift obtained by the large diameter propeller 61 is 3 to 8. The width of lift obtained by the small diameter propeller 71 is 1 to 6. The lower limit of the lift obtained by the large diameter propeller 61 is 3, and if the lift is lower than this, that is, if the rotational speed is reduced below this, the large diameter propeller 61 loses its function and the aircraft falls. The lower limit of the lift obtained by the small diameter propeller 71 is 1, and if the rotational speed is lowered below this, the small diameter propeller 71 loses its function and the aircraft falls.

  Then, in FIG. 3, the multicopter 10 is in the hovering state when the lift force is 5, and the altitude at that time is maintained. Here, it is assumed that the multicopter 10 is swept by, for example, a sudden updraft, and the lift required for hovering is reduced to 2 (FIG. 4). At this time, for example, assuming that the multicopter 10 has only the large diameter propeller 61, if the rotational speed of the large diameter propeller 61 is reduced to maintain the height of the multicopter 10, the lift of the large diameter propeller 61 is When it is less than 3, the large diameter propeller 61 loses its function and the multicopter 10 falls.

  On the other hand, in addition to the large diameter propeller 61, the multicopter 10 of this example also includes a small diameter propeller 71. In the multicopter 10, the lift 4 at which the lift 1 is added as a margin for securing safety to the lift 3 which is the lower limit of the rotation speed of the large diameter propeller 61 is used as the threshold for driving the small diameter propeller 71. The multicopter 10 starts driving the small diameter propeller 71 when the lift of the large diameter propeller 61 falls below four. Then, even after the large diameter propeller 61 loses its function, the small diameter propeller 71 is driven by the lifting force 2 to maintain the altitude of the vehicle.

  As described above, the multicopter 10 of this example includes the small diameter propeller 71, thereby expanding the steerable range of the multicopter 10 in the range of lifts 1 to 3. That is, the steering stability of the multicopter 10 is enhanced.

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described. In the following description, the same or similar configuration as that of the previous embodiment is denoted by the same reference numeral as that of the previous embodiment, and the detailed description thereof is omitted.

(Configuration outline)
FIG. 5 is a perspective view showing the appearance of the multicopter 10 a according to the present embodiment (hereinafter, also referred to as “the present example”). The multicopter 10a of this example is an airframe for the purpose of spraying a pesticide. Such pesticide spraying machines have the property that the total weight changes significantly before and after spraying pesticides.

  The multicopter 10a mainly includes a shell 11 which is a case body for housing a control system, eight arms 12 made of cylindrical pipe members, a rotor 60 having a large pitch propeller 62, and a rotor 70 having a small pitch propeller 72. And a pump device 92 which is an external device for spraying the agrochemicals. The large pitch propeller 62 is a type of the high lift propeller of the present invention, and the small pitch propeller 72 is a type of the small lift propeller of the present invention.

  The large pitch propeller 62 and the small pitch propeller 72 are propellers having different pitch angles. The small pitch propeller 72 employs a propeller having a pitch angle smaller than that of the large pitch propeller 62, and the large pitch propeller 62 and the small pitch propeller 72 are fixed so that the lift is adjusted by controlling the rotational speed. It is a pitch propeller. The ratio of the pitch angles of the large pitch propeller 62 and the small pitch propeller 72 is not specifically limited because of the same reason as the large diameter propeller 61 and the small diameter propeller 71 of the first embodiment. The ratio of the pitch angle of the large pitch propeller to the small pitch propeller may be set to an optimum ratio according to the flight environment, taking into consideration the balance between resistance to disturbance such as rising air flow and efficiency.

  The arms 12 of the multicopter 10 a radially extend from the shell 11 in the horizontal direction, and they are equally spaced around the shell 11 along the circumferential direction thereof. A large pitch propeller 62 (rotor 60) and a small pitch propeller 72 (rotor 70) are disposed at the tip of each arm 12, and the large pitch propeller 62 and the small pitch propeller 72 alternate along the circumferential direction of the shell 11. Is located in

(Functional configuration)
FIG. 6 is a block diagram showing the functional configuration of the multicopter 10a of this embodiment. The difference in functional configuration between the multicopter 10 of the first embodiment and the multicopter 10a of this example is that the large lift propeller is a large pitch propeller 62, the small lift propeller is a small pitch propeller 72, and mounted These are only the types of external devices (camera 91, pump device 92) and the control method (described later) of the rotors 60 and 70 by the flight control program FS.

(Propeller configuration)
The flight control program FS of this example drives both the large pitch propeller 62 (rotor 60) and the small pitch propeller 72 (rotor 70) simultaneously to fly the multicopter 10a. The principle of improving the steering stability of the multicopter 10a by providing the large pitch propeller 62 and the small pitch propeller 72 is the same as the large diameter propeller 61 and the small diameter propeller 71 of the first embodiment. That is, by providing the small pitch propeller 72 in addition to the large pitch propeller 62, the steerable range of the multicopter 10a is expanded.

  FIG. 7 and FIG. 8 are schematic diagrams showing the change of the required lift before and after the spraying of the pesticide. FIG. 7 shows a state before spraying pesticides, that is, when the pesticide tank is fully filled with pesticides. FIG. 8 shows the state after spraying the pesticide, that is, when the pesticide tank is empty. 7 and 8 are schematic diagrams in which details are simplified by emphasizing only the main points for convenience of explanation, and they do not exactly correspond to the actual situation.

  As shown in FIG. 7, the multicopter 10 a before pesticide spraying is configured such that the sum of maximum lift of the small pitch propeller 72 is smaller than the total weight of the multicopter 10 a. Here, the "total weight" in this example refers to the weight in a state where the pesticide tank is fully filled with pesticides and the total weight of the multicopter 10a is maximized, and does not include the total weight after spraying the pesticide .

  On the other hand, the small pitch propellers 72 are arranged in a quadcopter position with respect to the shell 11, and the small pitch propellers 72 alone can control the attitude of the vehicle. That is, although the altitude of the multicopter 10a can not be maintained by the small pitch propeller 72 alone, it is possible to maintain the level of the aircraft during descent. In this example, by making it possible to maintain the level of the airframe with only the small pitch propeller 72, it is possible to softly land the airframe with the small pitch propeller 72 even if all the functions of the large pitch propeller 62 are lost. There is.

  Then, as shown in FIG. 8, the lift of the multicopter 10 a after the agrochemical spraying is reduced to 4 necessary for maintaining the altitude because the airframe has become lighter. That is, when the multicopter 10a includes only the large pitch propeller 62, the large pitch propeller 62 loses its function only because the multicopter 10a is subjected to the updraft corresponding to the lift force 1. The multicopter 10a includes the small pitch propeller 72 in addition to the large pitch propeller 62 so that the small pitch propeller 72 supports the airframe even if the large pitch propeller 62 loses its function due to such disturbance. Can escape the fall of the aircraft.

  Usually, the propellers of rotary-wing aircraft need to maintain the number of revolutions without losing the controllability of the fuselage. In this example, only the rotational speed of the large pitch propeller 62 can be lowered to a level at which the function is lost, and the low pitch propeller 72 maintains the control function of the airframe to significantly lower the lower limit of lift of the multicopter 10a. Is possible.

  As mentioned above, although embodiment of this invention was described, the range of this invention is not limited to this, A various change can be added in the range which does not deviate from the main point of invention.

10, 10a multicopter (unmanned aerial vehicle (rotor aircraft))
FC flight controller 60 rotor 61 large diameter propeller (high lift propeller (horizontal rotor))
62 Large Pitch Propeller (High Lift Propeller (Horizontal Rotor Blade))
70 Rotor 71 Small Diameter Propeller (Low Lift Propeller (Horizontal Rotor Blade))
72 Small Pitch Propeller (Low Lift Propeller (Horizontal Rotor Blade))

Claims (8)

A rotary wing aircraft comprising a plurality of horizontal rotary wings,
The plurality of horizontal rotary wings include a large diameter propeller and a small diameter propeller that are propellers of different diameters, or a large pitch propeller and a small pitch propeller that are propellers of different pitch angles,
When the large diameter propeller and the large pitch propeller are referred to as a large lift propeller, and the small diameter propeller and the small pitch propeller are referred to as a small lift propeller,
The large lift propeller and the small lift propeller are fixed pitch propellers whose lift is adjusted by controlling the rotational speed,
The low lift propeller is driven when the rotational speed of the high lift propeller falls below a predetermined threshold. A rotary wing aircraft comprising a plurality of horizontal rotary wings,
The plurality of horizontal rotary wings include a large diameter propeller and a small diameter propeller that are propellers of different diameters, or a large pitch propeller and a small pitch propeller that are propellers of different pitch angles,
When the large diameter propeller and the large pitch propeller are referred to as a large lift propeller, and the small diameter propeller and the small pitch propeller are referred to as a small lift propeller,
The large lift propeller and the small lift propeller are fixed pitch propellers whose lift is adjusted by controlling the rotational speed,
A rotary wing aircraft characterized in that it is possible to reduce the number of revolutions of the high lift propeller during the flight below the number of revolutions at which its gyro effect or lift is lost. Having a plurality of said low lift propellers,
The rotary wing aircraft according to claim 1 or 2, wherein the plurality of low lift propellers are disposed at positions where the level of the fuselage can be maintained with only the low lift propellers.   The high lift propeller and the low lift propeller are provided in a one-to-one combination, and the high lift propeller and the low lift propeller of each set are coaxially arranged. A rotary wing aircraft according to any one of the preceding claims. Each set of high lift propellers and low lift propellers can be driven simultaneously,
The rotary wing aircraft according to any one of claims 1 to 4, wherein each of the small lift propellers is disposed on the exhaust side of the pair of the large lift propellers.   The rotary wing aircraft according to claim 3, wherein the sum of maximum lift of the small lift propellers is smaller than the weight of the rotary wing aircraft.   The rotor aircraft according to any one of claims 1 to 6, wherein the sum of the maximum lifts of the large lift propellers is larger than the sum of the maximum lifts of the small lift propellers.   The rotary wing aircraft according to any one of claims 1 to 7, which is an unmanned aerial vehicle.

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