A lightweight coaxial unmanned aerial vehicle full-flapping hub

Abstract

The application discloses a kind of full flapping hub of light coaxial unmanned aerial vehicle, including hub fixed seat, the hub fixed seat is symmetrically installed at the both ends of main shaft, the hub fixed seat is fixedly connected with tensile torsion strip, the tensile torsion strip is symmetrically arranged at the both sides of hub fixed seat, and the tensile torsion strip end is fixedly connected with paddle clamp rocker arm, paddle clamp.The hub of the design is applied to small coaxial unmanned helicopter, is installed at the both ends of main shaft, is controlled by the inclinometer of middle steering wheel, inclinometer transmits control, adjusts the attitude of hub, finally realizes the control of paddle blade;The hub of the design has complete flapping hinge and pitch hinge control paddle blade, can realize accurate and stable control to paddle blade, and the flight attitude of fuselage is more stable.Meanwhile, weight reduction is fully considered in design, and the dead weight is reduced to minimum, to improve the effective load of aircraft.

Description

Technical Field

[0001] This invention relates to the field of small coaxial drone technology, specifically to a lightweight coaxial drone with a fully waving propeller hub. Background Technology

[0002] The biggest advantages of small drones are their lightweight and low cost, leading to a wide range of applications, including military, agriculture, aerial photography, consumer entertainment, rescue, exploration, security, and logistics. Consumer entertainment drones hold a significant market share, while military drones, with their advanced technology, command relatively higher prices. With continuous technological innovation, small drones are becoming smaller, lighter, and more intelligent, equipped with more advanced sensors and cameras, resulting in more powerful and versatile functions.

[0003] Chinese Patent Application No. 202120372407.2 discloses an automatic folding rotor hub for a coaxial UAV, including a main shaft, a motor fixed to the top of the main shaft, a rotor hub seat fastened to the bottom of the motor, and a foldable rotor hub structure mounted on the rotor hub seat. It also includes a torsion spring. The foldable rotor hub structure includes a rotor hub bracket mounted at the bottom of the rotor hub seat and a first rotor hub segment pivotally connected to the rotor hub bracket. The first rotor hub segment can be folded relative to the rotor hub bracket. The torsion spring is located between the first rotor hub segment and the rotor hub bracket and elastically connects the rotor hub bracket and the first rotor hub segment at opposite ends.

[0004] The aforementioned disclosed technologies lack complete flapping and pitch control of the propeller blades, making precise and stable control of the blades impossible and resulting in unstable fuselage flight attitude. Furthermore, the design did not consider weight reduction, resulting in a relatively high weight and low payload. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a lightweight coaxial UAV with a fully flapping rotor hub. This solves the problems of existing technologies lacking complete flapping and pitch hinges for rotor blade control, resulting in inaccurate and unstable rotor blade control and flight attitude instability. Furthermore, the design does not consider weight reduction, leading to a relatively high weight and low payload.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A lightweight coaxial UAV fully flapping propeller hub includes a propeller hub mounting base, which is symmetrically installed at both ends of a main shaft. A tension bar is fixedly connected to the propeller hub mounting base, and the tension bar is symmetrically arranged on both sides of the propeller hub mounting base. The end of the tension bar is fixedly connected to a propeller clamp rocker arm and a propeller clamp.

[0008] Preferably, the propeller hub mounting base is connected to the brushless motor, and the brushless motor is fixed to the main shaft by bolt locking.

[0009] Preferably, the propeller hub mounting base is connected to the swashplate moving coil via an anti-torsion arm and a ball joint rod, and transmits servo control.

[0010] Preferably, the tension bar is made of eight overlapping 0.1mm thick spring steel sheets.

[0011] Preferably, the rotor hub mounting base is equipped with a flapping bushing and a flapping shaft at both ends, and the flapping bushing is sleeved on the outer periphery of the flapping shaft;

[0012] The waving bushing is provided with a first rotating hole, and the waving shaft is provided with a second rotating hole, with the first rotating hole and the second rotating hole having the same center.

[0013] A stainless steel horizontal shaft is fixedly connected to the propeller clamp, and the stainless steel horizontal shaft is inserted into the first rotating hole and the second rotating hole.

[0014] Preferably, the end of the pull-torsion bar is provided with a third connecting hole;

[0015] The paddle clamp rocker arm is provided with second connection holes on both sides;

[0016] The propeller clip is provided with a first connection hole;

[0017] The propeller clamp is inserted into the propeller clamp rocker arm, and the first connecting hole and the second connecting hole coincide.

[0018] Connecting bolts are inserted into the first connecting hole, the second connecting hole, and the third connecting hole.

[0019] Preferably, the propeller clamp and the propeller blade are connected by a connecting device;

[0020] The connecting device includes a first connecting plate and a second connecting plate. The first connecting plate is fixedly connected to the propeller clamp, and the second connecting plate is fixedly connected to the propeller blade. The first connecting plate and the second connecting plate are rotatably connected.

[0021] A first connecting side plate is fixedly connected to the first connecting plate, and a second connecting side plate is fixedly connected to the second connecting plate. The first connecting side plate is perpendicular to the first connecting plate, and the second connecting side plate is perpendicular to the second connecting plate. The first connecting side plate and the second connecting side plate partially overlap.

[0022] A connecting shaft is rotatably connected through the first connecting side plate and the second connecting side plate.

[0023] Preferably, a sliding groove is provided on the first connecting side plate, and a locking rod is slidably connected in the sliding groove. One end of a spring is connected to the locking rod, and the other end of the spring is connected to the inner wall of the first connecting side plate.

[0024] The two ends of the locking rod are located on the outside of the first connecting side plate. The two ends of the locking rod are rotatably connected to the adjusting handles. The adjusting handles are fixedly connected to the adjusting rods, and the adjusting rods are arranged parallel to the locking rods.

[0025] The second connecting side plate is provided with several sets of clips and positions, and the line connecting two adjacent sets of clips and positions forms an angle with the connecting shaft;

[0026] The lever is engaged within the locking position.

[0027] Preferably, the speed control of the brushless motor is performed by the following method:

[0028] Obtain the actual speed and torque of the brushless motor, as well as the altitude of the drone;

[0029] Based on the parameters of the brushless motor, the altitude of the drone, and the actual torque, the working state of the drone is determined, which is either ascending, descending, or level flight.

[0030] The target speed of the brushless motor is determined based on the drone's operating status and the actual rotational speed corresponding to that operating status.

[0031] Preferably, determining the target speed of the brushless motor includes:

[0032] The correction coefficient is determined based on the drone's operating status and the corresponding actual rotational speed.

[0033] The target speed of the brushless motor is determined based on the drone's operating status and correction factor.

[0034] Compared with the prior art, the present invention has at least the following beneficial effects:

[0035] This application provides a single propeller hub, symmetrically mounted at both ends of the main shaft. The upper part of the propeller hub is connected to a brushless motor, which is fixed to the main shaft by bolts. The lower part of the propeller hub is connected to the swashplate moving coil via an anti-torsion arm and a ball joint rod, transmitting control to the servo motor.

[0036] The torsion bar is composed of eight overlapping 0.1mm thick spring steel sheets. Two torsion bars are symmetrically fixed to the propeller hub mounting base, and their ends are fixed to the propeller clamp rocker arm and propeller clamp by screws. Due to the elasticity of the torsion bar, the propeller clamp rocker arm can drive the propeller clamp to rotate around the stainless steel horizontal axis to change the torque, thereby controlling the movement of the fuselage.

[0037] The flapping shaft and flapping shaft sleeve are installed at both ends of the propeller hub mounting base. After the end of the stainless steel horizontal shaft fixed with the propeller clamp is inserted into the center hole of the flapping shaft and the sleeve, it can rotate up and down within a certain range around the flapping shaft. This helps the propeller blade to rise or fall naturally when rotating, balances the lift on both sides, increases the stability of the flight attitude, and at the same time limits the flapping angle to avoid propeller blade collision.

[0038] This application presents a lightweight coaxial UAV full-flapping rotor hub design. Structurally, it uses as few parts as possible to arrange the pitch hinge and flapping hinge within a limited space. The material and thickness of the tension bar have been tested and, while connecting the rotor clamp, the rebound force acts as a damping effect, reducing sudden changes in force during control and increasing control stability. In terms of weight, the rotor hub mounting base, rotor clamp, and rotor clamp rocker arm are made of 6061 aluminum, while the tension bar, flapping shaft, and stainless steel cross shaft are made of steel. The flapping shaft sleeve is made of brass to consider wear resistance. Each part has a weight reduction design to minimize weight while ensuring strength. Including all finished and standard parts, the entire full-flapping rotor hub weighs 210g. For small unmanned helicopters, reducing weight and increasing payload is of great significance.

[0039] This rotor hub design is applied to small coaxial unmanned helicopters. It is installed at both ends of the main shaft and the swashplate is controlled by the servo motor in the middle. The swashplate transmits control and adjusts the rotor hub attitude, ultimately achieving control of the rotor blades.

[0040] The rotor hub of this design features complete flapping and pitch control blades, enabling precise and stable control of the blades and resulting in greater stability of the aircraft's flight attitude. Simultaneously, the design prioritizes weight reduction, minimizing the aircraft's weight and maximizing its payload. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the main structure of the present invention;

[0042] Figure 2 This is a schematic diagram of the tension bar connection structure of the present invention;

[0043] Figure 3 This is a schematic diagram of the waving shaft connection structure of the present invention;

[0044] Figure 4 This is a schematic diagram of the unfolded structure of the connecting device of the present invention;

[0045] Figure 5 This is a schematic diagram of the folding structure of the connecting device of the present invention.

[0046] In the diagram: 1. Main shaft; 2. Brushless motor; 3. Anti-torsion arm; 4. Ball joint tie rod; 5. Propeller hub mounting base; 6. Torsion bar; 7. Propeller clamp rocker arm; 8. Stainless steel horizontal shaft; 9. Propeller clamp; 10. Swinging bushing; 11. Swinging shaft; 12. First rotating hole; 13. Second rotating hole; 14. First connecting hole; 15. Second connecting hole; 16. Third connecting hole; 17. Connecting bolt; 18. First connecting plate; 19. Second connecting plate; 20. First connecting side plate; 21. Second connecting side plate; 22. Connecting shaft; 23. Locking position; 24. Locking rod; 25. Adjusting rod; 26. Adjusting handle; 27. Spring; 28. Slide groove. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0048] Example 1

[0049] Please see Figure 1-3 The present invention provides a technical solution: a lightweight coaxial drone full-flare propeller hub, including a propeller hub fixing seat 5, the propeller hub fixing seat 5 being symmetrically installed at both ends of the main shaft 1, a tension bar 6 being fixedly connected to the propeller hub fixing seat 5, the tension bar 6 being symmetrically arranged on both sides of the propeller hub fixing seat 5, and the end of the tension bar 6 being fixedly connected to the propeller clamp rocker arm 7 and the propeller clamp 9.

[0050] Preferably, the propeller hub mounting base 5 is connected to the brushless motor 2, and the brushless motor 2 is fixed to the main shaft 1 by bolt locking.

[0051] Preferably, the propeller hub mounting base 5 is connected to the swashplate moving coil via the anti-torsion arm 3 and the ball joint rod 4, and transmits servo control.

[0052] Preferably, the tension bar 6 is made of eight overlapping 0.1mm thick spring steel sheets.

[0053] Preferably, the hub mounting base 5 is equipped with a waving bushing 10 and a waving shaft 11 at both ends, and the waving bushing 10 is sleeved on the outer periphery of the waving shaft 11.

[0054] The waving bushing 10 is provided with a first rotating hole 12, and the waving shaft 11 is provided with a second rotating hole 13. The first rotating hole 12 and the second rotating hole 13 are arranged with the same center.

[0055] A stainless steel horizontal shaft 8 is fixedly connected to the paddle clamp 9, and the stainless steel horizontal shaft 8 is inserted into the first rotating hole 12 and the second rotating hole 13.

[0056] Preferably, the end of the pull-torsion bar 6 is provided with a third connecting hole 16;

[0057] The propeller clamp rocker arm 7 is provided with second connection holes 15 on both sides;

[0058] The paddle clip 9 is provided with a first connecting hole 14;

[0059] The propeller clip 9 is inserted into the propeller clip rocker arm 7, and the first connecting hole 14 and the second connecting hole 15 coincide.

[0060] Connecting bolts 17 are inserted into the first connecting hole 14, the second connecting hole 15, and the third connecting hole 16.

[0061] The working principle and beneficial effects of the above scheme are as follows:

[0062] This application provides a rotor hub with two rotors, symmetrically mounted at both ends of the main shaft 1. The upper part of the rotor hub is connected to the brushless motor 2, which is fixed to the main shaft 1 by bolts. The lower part of the rotor hub is connected to the swashplate moving coil via an anti-torsion arm 3 and a ball joint rod 4, and transmits servo control.

[0063] The torsion bar 6 is composed of eight overlapping 0.1mm thick spring steel sheets. Two torsion bars 6 are symmetrically fixed on the propeller hub mounting base 5, and their ends are fixed to the propeller clamp rocker arm 7 and the propeller clamp 9 by screws. Because the torsion bar 6 has a certain degree of elasticity, the propeller clamp rocker arm 7 can drive the propeller clamp 9 to rotate around the stainless steel horizontal axis 8 to change the torque, thereby achieving the purpose of controlling the movement of the fuselage.

[0064] The flapping shaft 11 and flapping shaft sleeve 10 are installed at both ends of the propeller hub fixing seat 5. After the end of the stainless steel horizontal shaft 8, which is fixed to the propeller clamp 9, is inserted into the center hole of the flapping shaft 11 and the sleeve 10, it can rotate up and down within a certain range around the center of the flapping shaft 11, which helps the propeller blade to rise or fall naturally when rotating, balances the lift on both sides, increases the stability of the flight attitude, and at the same time limits the flapping angle in the structure to avoid the propeller blade collision.

[0065] This application presents a lightweight coaxial UAV full-flapping rotor hub design. Structurally, it uses as few parts as possible to arrange the pitch hinge and flapping hinge within a limited space. The material and thickness of the tension bar 6 have been tested. While connecting the rotor clamp, the rebound force acts as a damping effect, reducing sudden changes in force during control and increasing control stability. In terms of weight, the rotor hub mounting base 5, rotor clamp 9, and rotor clamp rocker arm 7 are made of 6061 aluminum, while the tension bar 6, flapping shaft 11, and stainless steel cross shaft 8 are made of steel. The flapping shaft sleeve 10 is made of brass to consider wear resistance. Each part has been designed to reduce weight. While ensuring strength, the weight is kept to a minimum. Including all finished and standard parts, the entire full-flapping rotor hub weighs 210g. For small unmanned helicopters, reducing weight and increasing payload is of great significance.

[0066] The rotor hub of this design is used in a small coaxial unmanned helicopter. It is installed at both ends of the main shaft 1. The swashplate is controlled by the servo motor in the middle. The swashplate transmits control and adjusts the attitude of the rotor hub, ultimately achieving control of the rotor blades.

[0067] The rotor hub of this design features complete flapping and pitch control blades, enabling precise and stable control of the blades and resulting in greater stability of the aircraft's flight attitude. Simultaneously, the design prioritizes weight reduction, minimizing the aircraft's weight and maximizing its payload.

[0068] Example 2

[0069] Please see Figure 4-5 Based on Embodiment 1, the propeller clamp 9 is connected to the propeller blade via a connecting device;

[0070] The connecting device includes a first connecting plate 18 and a second connecting plate 19. The first connecting plate 18 is fixedly connected to the propeller clamp 9, and the second connecting plate 19 is fixedly connected to the propeller blade. The first connecting plate 18 and the second connecting plate 19 are rotatably connected.

[0071] A first connecting side plate 20 is fixedly connected to the first connecting plate 18, and a second connecting side plate 21 is fixedly connected to the second connecting plate 19. The first connecting side plate 20 is perpendicular to the first connecting plate 18, and the second connecting side plate 21 is perpendicular to the second connecting plate 19. The first connecting side plate 20 and the second connecting side plate 21 partially overlap.

[0072] A connecting shaft 22 is rotatably connected through the first connecting side plate 20 and the second connecting side plate 21.

[0073] The first connecting side plate 20 is provided with a sliding groove 28, and a locking rod 24 is slidably connected in the sliding groove 28. One end of a spring 27 is connected to the locking rod 24, and the other end of the spring 27 is connected to the inner wall of the first connecting side plate 20.

[0074] The two ends of the locking rod 24 are located outside the first connecting side plate 20. The two ends of the locking rod 24 are rotatably connected to the adjusting handle 26. An adjusting rod 25 is fixedly connected to the adjusting handle 26. The adjusting rod 25 is arranged parallel to the locking rod 24.

[0075] The second connecting side plate 21 is provided with several sets of clips and positions 23, and the line connecting two adjacent sets of clips and positions 23 and the connecting shaft 22 forms an angle;

[0076] The number of several sets of cards and positions 23, and the angle formed by the line connecting two adjacent sets of cards and positions 23 and the connecting shaft 22 are all set according to the actual usage scenario;

[0077] The lever 24 is engaged within the locking position 23.

[0078] The working principle and beneficial effects of the above scheme are as follows:

[0079] After the drone stops flying, the propeller blades can be bent so that they fit against the side of the fuselage, avoiding the space occupied by long propeller blades and increasing the drone's portability.

[0080] When the blade is bent, the second connecting plate 19 rotates relative to the first connecting plate 18 around the connecting shaft 22. The adjustment handle 26 needs to be pulled in advance to disengage the locking rod 24 from the locking position 23. Then the second connecting plate 19 is bent. When the second connecting plate 19 is bent to the appropriate position, the locking rod 24 will be locked into another locking position 23 under the action of the spring 27, thus completing the fixation of the blade after bending.

[0081] Before and after the blade bends, there are locking rods 24 and locking positions 23, and the locking rods 24 are always under the tension of the spring 27, which ensures the stability of the blade before and after bending and avoids damage to the blade.

[0082] Example 3

[0083] Based on Example 1, the speed control of the brushless motor 2 is performed through the following methods:

[0084] Obtain the actual rotational speed and actual torque of brushless motor 2, as well as the altitude of the drone;

[0085] Based on the parameters of the brushless motor 2, the altitude of the drone, and the actual torque, the working state of the drone is determined, which is the ascending working state, the descending working state, or the level flight working state.

[0086] The target speed of brushless motor 2 is determined based on the drone's operating status and the actual rotation speed corresponding to the drone's operating status.

[0087] Determining the target speed of brushless motor 2 includes:

[0088] The correction coefficient is determined based on the drone's operating status and the corresponding actual rotational speed.

[0089] The target rotational speed of brushless motor 2 is determined based on the operating status of the drone and the correction coefficient.

[0090] The working principle and beneficial effects of the above scheme are as follows:

[0091] By using the above methods, the speed of the brushless motor 2 is automatically controlled according to the working mode of the drone and the detected working status of the brushless motor 2, so that the speed of the brushless motor 2 can adapt to the flight state of the drone and ensure the stable flight of the drone.

[0092] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Moreover, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0093] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lightweight coaxial unmanned aerial vehicle (UAV) with a fully flailing propeller hub, characterized in that: Includes a propeller hub mounting base (5), which is symmetrically installed at both ends of the main shaft (1). A torsion bar (6) is fixedly connected to the propeller hub mounting base (5). The torsion bar (6) is symmetrically arranged on both sides of the propeller hub mounting base (5). The end of the torsion bar (6) is fixedly connected to the propeller clamp rocker arm (7) and the propeller clamp (9). The hub mounting base (5) is equipped with a waving bushing (10) and a waving shaft (11) at both ends, and the waving bushing (10) is sleeved on the outer periphery of the waving shaft (11); The waving bushing (10) is provided with a first rotating hole (12), and the waving shaft (11) is provided with a second rotating hole (13). The first rotating hole (12) and the second rotating hole (13) are arranged with the same center. A stainless steel horizontal shaft (8) is fixedly connected to the paddle clamp (9), and the stainless steel horizontal shaft (8) is inserted into the first rotating hole (12) and the second rotating hole (13). The end of the pull-torsion bar (6) is provided with a third connecting hole (16); The paddle clamp rocker arm (7) is provided with second connecting holes (15) on both sides; The paddle clip (9) is provided with a first connecting hole (14); The propeller clip (9) is inserted into the propeller clip rocker arm (7), and the first connecting hole (14) and the second connecting hole (15) coincide. Connecting bolts (17) are inserted into the first connecting hole (14), the second connecting hole (15), and the third connecting hole (16).

2. The lightweight coaxial UAV with a fully flailing rotor hub according to claim 1, characterized in that: The propeller hub mounting base (5) is connected to the brushless motor (2), and the brushless motor (2) is fixed to the main shaft (1) by bolt locking.

3. The lightweight coaxial UAV with a fully waving propeller hub according to claim 1, characterized in that: The propeller hub mounting base (5) is connected to the swashplate moving coil via the anti-torsion arm (3) and the ball joint rod (4), and transmits servo control.

4. The lightweight coaxial UAV with a fully waving propeller hub according to claim 1, characterized in that: The tension bar (6) is made of eight 0.1mm thick spring steel sheets stacked together.

5. The lightweight coaxial UAV with a fully waving propeller hub according to claim 1, characterized in that: The propeller clip (9) is connected to the propeller blade via a connecting device; The connecting device includes a first connecting plate (18) and a second connecting plate (19). The first connecting plate (18) is fixedly connected to the propeller clamp (9), and the second connecting plate (19) is fixedly connected to the propeller blade. The first connecting plate (18) and the second connecting plate (19) are rotatably connected. A first connecting side plate (20) is fixedly connected to the first connecting plate (18), and a second connecting side plate (21) is fixedly connected to the second connecting plate (19). The first connecting side plate (20) is perpendicular to the first connecting plate (18), and the second connecting side plate (21) is perpendicular to the second connecting plate (19). The first connecting side plate (20) and the second connecting side plate (21) partially overlap. A connecting shaft (22) is rotatably connected through the first connecting side plate (20) and the second connecting side plate (21).

6. A lightweight coaxial UAV with a fully flailing rotor hub according to claim 5, characterized in that: The first connecting side plate (20) is provided with a sliding groove (28), and a locking rod (24) is slidably connected in the sliding groove (28). One end of a spring (27) is connected to the locking rod (24), and the other end of the spring (27) is connected to the inner wall of the first connecting side plate (20). The two ends of the lever (24) are located outside the first connecting side plate (20). The two ends of the lever (24) are rotatably connected to the adjustment handle (26). An adjustment rod (25) is fixedly connected to the adjustment handle (26). The adjustment rod (25) is arranged parallel to the lever (24). The second connecting side plate (21) is provided with a number of sets of clips and positions (23), and the line connecting two adjacent sets of clips and positions (23) and the connecting shaft (22) forms an angle; The lever (24) is engaged in the locking position (23).

7. A lightweight coaxial UAV with a fully flailing rotor hub according to claim 2, characterized in that: The speed control of the brushless motor (2) is performed by the following methods, including: Obtain the actual speed and torque of the brushless motor (2), and obtain the altitude of the UAV; Based on the parameters of the brushless motor (2), the altitude of the UAV and the actual torque, the working state of the UAV is determined, which is the ascending working state, the descending working state or the level flight working state. The target speed of the brushless motor (2) is determined based on the working status of the UAV and the actual speed corresponding to the working status of the UAV.

8. A lightweight coaxial UAV with a fully flailing rotor hub according to claim 7, characterized in that: Determining the target speed of the brushless motor (2) includes: The correction coefficient is determined based on the drone's operating status and the corresponding actual rotational speed. The target rotational speed of the brushless motor (2) is determined based on the working status of the UAV and the correction coefficient.

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