Composite aircraft integrating coaxial multi-rotor wings and tilting multi-rotor wings

Abstract

The utility model discloses a composite aircraft integrating coaxial multi-rotor wings and tilting multi-rotor wings. The composite aircraft comprises an aircraft body, a hollow supporting column, at least two main lift force rotor wing assemblies and at least two tilting rotor wing assemblies. The lower end of the hollow supporting column is arranged on the upper surface of the machine body. A load is installed at the upper end of the hollow supporting column. According to the main lift rotor assembly, a first motor is installed on a hollow supporting column, the hollow supporting column is sleeved with a main lift rotor, and the first motor is connected with the main lift rotor; according to the tilting rotor assembly, an output shaft of a steering engine is connected with one end of a rotating shaft; a second motor is mounted at the other end of the rotating shaft and is connected with the tilting rotor; the steering engine is mounted on the fuselage, so that the rotating shafts extend outwards from the side surface of the fuselage, and the included angles between any two adjacent rotating shafts are the same; the size of the main lift rotor is larger than that of the tilting rotors, so that the tilting rotors are all located under the main lift rotor. The scheme is high in hovering and low-speed flight efficiency, low in noise and small in dead weight.

Description

Technical Field

[0001] The utility model relates to the technical field of unmanned aerial vehicles, in particular to a composite aircraft integrating coaxial multi-rotors and tilting multi-rotors. Background Art

[0002] There are many types of aircraft, including helicopters, multi-rotors, fixed-wing aircraft, and some aircraft with specialized structures. Helicopters, multi-rotors, and vertical take-off and landing fixed-wing aircraft all possess the ability to hover and maintain a constant speed, and have found application in specific industries. Low-altitude logistics and civilian aerial photography applications place high demands on aircraft performance in terms of hovering efficiency, low-speed flight efficiency, safety, and noise. These operating environments impose even stricter and more comprehensive requirements on various aircraft performance characteristics.

[0003] Helicopters generally have higher hovering efficiency than multi-rotors and vertical take-off and landing fixed-wing aircraft, but their variable pitch structures are complex, difficult to miniaturize, and lack mechanical reliability. Multi-rotors have simple and reliable structures, but their hovering and flight efficiency are not outstanding. Vertical take-off and landing fixed-wing aircraft have higher mid- and high-speed flight efficiency than helicopters and multi-rotors, but their hovering and low-speed flight efficiency are lower. Among the many existing aircraft solutions, although multi-rotors do not excel in all aspects of indicators, they have been widely used in the civilian field due to their simple structure, flexible modification, and miniaturization. However, in actual applications, they often need to be combined with specific application requirements to achieve the desired function, and there is still considerable room for improvement in performance.

[0004] A tilt-rotor multirotor aircraft can be seen as a traditional multirotor aircraft or fixed-wing aircraft with tilt-rotor servos added to it, which can change the orientation of the powered rotor, thereby achieving more flexible lift direction control or enabling the reuse of the powered rotor in different flight modes, thereby improving the maneuverability of the aircraft or reducing the number of powered rotors.

[0005] For application scenarios such as low-altitude logistics and aerial photography, existing aircraft have room for improvement in terms of efficiency and performance. Utility Model Content

[0006] An embodiment of the present utility model provides a composite aircraft integrating a coaxial multi-rotor and a tilt-multi-rotor to solve the problems of low efficiency and poor performance of existing aircraft in application scenarios such as low-altitude logistics and aerial photography.

[0007] The present utility model discloses the following technical solutions:

[0008] A composite aircraft integrating a coaxial multi-rotor and a tilt-rotor multi-rotor, comprising: a fuselage, a hollow support column, at least two main lift rotor assemblies, and at least two tilt-rotor assemblies; the lower end of the hollow support column is fixedly disposed on the upper surface of the fuselage, and the upper end of the hollow support column is used to mount a load;

[0009] Each of the main lift rotor assemblies includes: a first motor and a main lift rotor, wherein the first motor is mounted on the hollow support column, and the main lift rotor is sleeved on the hollow support column, and the first motor is connected to the main lift rotor to drive the main lift rotor to rotate around the hollow support column; two adjacent main lift rotors are spaced apart;

[0010] Each of the tilt-rotor assemblies includes: a steering gear, a rotating shaft, a second motor, and a tilt-rotor, wherein the output shaft of the steering gear is connected to one end of the rotating shaft to drive the rotating shaft to rotate; the second motor is mounted on the other end of the rotating shaft, and the second motor is connected to the tilt-rotor to drive the tilt-rotor to rotate; the steering gear of each tilt-rotor assembly is mounted on the fuselage so that the rotating shaft of each tilt-rotor assembly extends outward from the side of the fuselage, and the angle between any two adjacent rotating shafts is the same;

[0011] The size of the main lift rotor is larger than that of the tilt rotor, so that the plurality of tilt rotors are located directly below the main lift rotor.

[0012] Furthermore: the fuselage is composed of multiple layers of fiberboard, and any two layers of the fiberboard are connected by multiple support rods that are evenly spaced.

[0013] Further: the servo is installed on any fiberboard located in the middle layer of the fuselage.

[0014] Further: a landing gear is installed on the lower surface of the fuselage.

[0015] Further: the landing gear is a foldable landing gear.

[0016] Further: a power source is provided on the fuselage, and the power source is electrically connected to the first motor, the steering gear and the second motor.

[0017] Further: a controller is provided on the fuselage, and the controller is electrically connected to the first motor, the steering gear and the second motor.

[0018] Furthermore: the number of the main lift rotor assemblies is two, and the two main lift rotors rotate forward and reverse at a differential speed.

[0019] Furthermore: the number of the tilt-rotor assemblies is four.

[0020] In this way, the embodiment of the utility model has higher efficiency and safety in hovering and low-speed flight, lower flight noise, smoother flight, less impact on load, smaller dead weight, and is conducive to improving flight time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 It is a schematic structural diagram of a composite aircraft according to an example of the present utility model;

[0023] Figure 2 It is a schematic structural diagram of a tilt-rotor assembly of a composite aircraft according to an example of the present utility model;

[0024] Figure 3 It is a schematic diagram of the mechanical environment of the main lift rotor and tilt rotor of the composite aircraft of the embodiment of the present utility model;

[0025] Figure 4 It is a schematic diagram of the state of the composite aircraft of the embodiment of the present utility model in the aircraft hovering or vertical take-off and landing mode;

[0026] Figure 5 This is a schematic diagram of the composite aircraft of the present utility model in a level flight mode;

[0027] Figure 6 It is a top view of the composite aircraft of the present invention in a level flight mode;

[0028] Figure 7 This is a schematic diagram of the composite aircraft of the present utility model in an aircraft failure flight mode;

[0029] Figure 8 This is a schematic diagram of a single-unit storage and transportation state of a composite aircraft according to an example of the present invention;

[0030] Figure 9 This is a schematic diagram of a multi-machine storage and transportation state of a composite aircraft according to an embodiment of the present invention;

[0031] Figure 10 1 is a schematic diagram comparing the experimental results of the composite aircraft of the present invention and the conventional aircraft, wherein (a) is not equipped with the main lift rotor, and (b) is equipped with the main lift rotor. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] The present invention discloses a composite aircraft integrating coaxial multi-rotor and tilt-rotor, which is suitable for low-altitude logistics and aerial photography. Figure 1 and 2 As shown, the composite aircraft includes: a fuselage 1, a hollow support column 2, at least two main lift rotor assemblies and at least two tilt rotor assemblies.

[0034] Specifically, the lower end of the hollow support column 2 is fixedly mounted on the upper surface of the fuselage 1, and the upper end of the hollow support column 2 is used to mount the payload 3. The payload 3 may include various sensors required for flight and actuators for achieving specific operational functions, such as a barometer, GPS, magnetometer, obstacle detection, parachute, monitoring, and robotic arms, and can be installed as needed.

[0035] Specifically, each main lift rotor assembly includes: a first motor 4 and a main lift rotor 5. The first motor 4 is installed on the hollow support column 2. The main lift rotor 5 is mounted on the hollow support column 2, and the first motor 4 is connected to the main lift rotor 5, which can drive the main lift rotor 5 to rotate around the hollow support column 2. The main lift rotor 5 usually adopts a two-blade propeller, and the main lift rotor 5 in different positions can be designed with different pitches to optimize flight efficiency. There is a distance between two adjacent main lift rotors 5. The main lift rotor 5 serves as the main power system of the composite aircraft, mainly providing lift and yaw angle attitude control for the composite aircraft efficiently, and can also assist in providing lateral thrust.

[0036] For example, the first motor 4 can be a direct-drive and hollow brushless outer rotor motor, and the fixed connection structure is located above the outer rotor of the motor. The fixed connection structure is used to connect the main lift rotor 5, so that the main lift rotor 5 is located above the outer rotor of the motor. The outer rotor of the motor can be rotatably mounted on the hollow support column 2, and the motor stator is fixedly mounted on the hollow support column 2. The main lift rotor 5, the outer rotor of the motor, the motor stator and the hollow support column 2 are coaxial.

[0037] For example, the first motor 4 can be a direct-drive and hollow brushless outer rotor motor, and the fixed connection structure is fixedly mounted on the periphery of the motor outer rotor. The fixed connection structure is used to connect the main lift rotor 5, so that the main lift rotor 5 is located on the periphery of the motor outer rotor. The motor stator is fixedly mounted on the hollow support column 2, and the main lift rotor 5, the motor outer rotor, the motor stator and the hollow support column 2 are coaxial.

[0038] The above two structures are simple and have high reliability.

[0039] For example, the first motor 4 may be a reduction motor, the reduction gear of which is rotatably mounted on the hollow support column 2. The main lift rotor 5 is fixedly mounted above the reduction gear. The reduction motor is mounted below the reduction gear and may be fixed to the side of the hollow support column 2 via a fixing structure. The output shaft of the reduction motor meshes with the reduction gear. The main lift rotor 5, the reduction gear, and the hollow support column 2 are coaxial.

[0040] The above structure is conducive to further reducing weight.

[0041] The interior of the hollow support column 2 can accommodate cables for various components that require circuit connection, thereby facilitating the routing of these components and protecting the cables.

[0042] In the above structural design, the main lift rotor 5 is arranged up and down without interfering with other structures, allowing the installation of a larger rotor. The larger rotor can provide lift with higher efficiency and increase the flight time.

[0043] The number of main lift rotor assemblies can be set according to actual conditions. Preferably, the number of main lift rotor assemblies is two, and the two main lift rotors 5 rotate forward and reverse at differential speeds to provide lift and offset the anti-torque to control the altitude and yaw angle of the aircraft.

[0044] Specifically, each tilt-rotor assembly includes a servo 6, a rotating shaft 7, a second motor 8, and a tilt-rotor 9. The output shaft of the servo 6 is connected to one end of the rotating shaft 7, driving the rotating shaft 7 to rotate. The second motor 8 is mounted on the other end of the rotating shaft 7. The second motor 8 is connected to the tilt-rotor 9, driving the tilt-rotor 9 to rotate. For example, the tilt-rotor 9 can be rotatably mounted on the output shaft of the second motor 8. The tilt-rotor assembly can be designed as a quick-release module to simplify maintenance and even enable hot swapping during flight. The servo 6 of each tilt-rotor assembly is mounted on the fuselage 1, such that the rotating shaft 7 of each tilt-rotor assembly extends outward from the side of the fuselage 1. The servo 6 and second motor 8 can be respectively secured to the fuselage 1 and the rotating shaft 7 via corresponding fixing structures. For example, a mounting bracket 11 is provided at the other end of the rotating shaft 7, on which the second motor 8 is mounted. The rotating shaft 7 can be made of carbon fiber to reduce weight. The angle between any two adjacent rotation axes 7 is the same, ensuring that the tilt rotors 9 are evenly spaced around the fuselage 1, allowing for stable adjustment of the aircraft's tilt angle. The multiple tilt rotors 9 serve as the composite aircraft's tilt propulsion system, primarily providing lateral forward propulsion, adjusting flight attitude, and assisting in lift regulation.

[0045] Preferably, a bearing 10 is provided at one end of the rotating shaft 7. The bearing 10 can be in the form of a double bearing. The outer side of the bearing 10 is connected and fixed to the fuselage 1 to ensure the flexible rotation of the rotor and bear all loads other than the torque of the rotating shaft 7. The servo 6 only needs to bear the rotational torque of the rotating shaft 7.

[0046] Each hybrid aircraft requires multiple tilt-rotors 9. A minimum of two tilt-rotors 9 ensures full control of the aircraft. The remaining tilt-rotors 9 facilitate control of the hybrid aircraft and provide safety redundancy. Preferably, there are four tilt-rotor assemblies, with four rotation axes 7 extending from the four corners of the square fuselage 1. This allows for angle adjustment in four directions, enabling the hybrid aircraft to tilt in all four directions: front, back, left, and right.

[0047] Specifically, the servo 6 drives the rotation shaft 7 to rotate, thereby driving the second motor 8 to tilt, changing the orientation of the tilt-rotor 9 and adjusting the direction of lift. The second motor 8 drives the tilt-rotor 9 to rotate, providing power for the hybrid aircraft, allowing for more flexible adjustment of the hybrid aircraft's speed and flight attitude. The maximum tilt angle of the rotation shaft 7 is determined by the maximum operating angle of the servo 6.

[0048] The main lift rotor 5 is larger than the tilt rotor 9, so that the plurality of tilt rotors 9 are located directly below the main lift rotor 5. Generally, the first motor 4 driving the main lift rotor 5 is also larger than the second motor 8 driving the tilt rotor 9.

[0049] Usually, due to the geometric overlap of space, there is a contradiction between reducing lift waste and producing lift efficiently. Reducing waste requires extending the tilt-rotor out of the downwash area of ​​the main lift rotor (to avoid airflow interference), which requires a heavier fuselage and limits the size of the main lift rotor; producing lift efficiently requires a larger propeller (lift production efficiency is positively correlated with propeller diameter). The existing technology uses a lighter rod to extend the tilt-rotor as far as possible, but due to material limitations, a rod that is too long and too light is prone to breakage. Therefore, it is necessary to actively limit the size of the main lift rotor, resulting in active limitation of lift generation efficiency. In addition, it is generally believed that aerodynamic interference between multi-rotor blades is an adverse effect that will inevitably cause the tilt-rotor to be affected by the downwash of the main lift rotor and should be avoided as much as possible.

[0050] However, the embodiment of the present invention adopts the above-mentioned structural design and adopts a smaller tilt-rotor 9. By actively utilizing aerodynamic interference, the aerodynamic interference caused by the large coaxial main lift rotor 5 is turned from a disadvantage into an advantage, thereby generating more lift more efficiently and significantly improving the flight time of the composite aircraft. Specifically,

[0051] In this embodiment of the present invention, the small tilt-rotor 9 is positioned directly below the large coaxial main lift rotor 5. This means that the main lift rotor 5 completely envelops the tilt-rotor 9, and the area directly below the coaxial main lift rotor 5 is affected by the downwash. This design eliminates the need to extend the small tilt-rotor 9 beyond the downwash by using a very long fuselage or mast. This design eliminates interference between the multiple vertically arranged main lift rotors 5 and other structures. Within the limits permitted by the material's structural strength, there's no need to actively limit the size of the main lift rotors 5. This significantly reduces fuselage weight and allows for the use of larger rotors. Larger rotors can more efficiently provide lift, significantly improving hovering efficiency and overall increasing the flight time of the hybrid aircraft. Furthermore, when there's minimal external interference, the tilt-rotor 9 operates in generator mode, recovering some energy from the downwash of the main lift rotor 5. The drag and torque generated during this energy recovery are used to adjust the aircraft's attitude and speed, maintaining the aircraft's attitude stability and thus reducing energy consumption during flight. When the tilt-rotor 9 operates in generator mode, the tilt-rotor assembly is structurally equivalent to a small fixed-pitch direct-drive wind turbine. Specifically, the tilt-rotor 9 is equivalent to the blades of the wind turbine, the second motor 8 is equivalent to the engine of the wind turbine, and the servo 6 is equivalent to the yaw motor of the wind turbine.

[0052] like Figure 3 As shown in the side view of the hybrid aircraft, when the hybrid aircraft is subjected to a small clockwise external torque disturbance, the left tilt-rotor 9 operates in generator mode, while the right tilt-rotor 9 rotates with the airflow. When generating electricity, the left tilt-rotor 9 encounters greater airflow resistance, resulting in a downward force, which generates a counterclockwise control torque on the hybrid aircraft, counteracting the external disturbance torque and maintaining the fuselage attitude unchanged.

[0053] To increase the size of the main lift rotor 5 in the composite aircraft of the present invention, it is only necessary to proportionally increase the length of the single hollow support column 2. Since the hollow support column 2 only bears tensile forces and is shorter than the radius of the main lift rotor 5, it does not need to bear tangential forces like the arms of a multi-rotor, and its length is longer than the rotor radius. Therefore, the hollow support column 2 is lighter than the arms of a multi-rotor. Furthermore, compared to a helicopter, the hollow support column 2 of the present invention embodiment does not need to rotate like a helicopter, and is therefore lighter. Furthermore, compared to existing coaxial helicopters, the main lift rotor 5 does not have a cyclic pitch structure and does not need to bear the torsional torque and lift changes caused by cyclic pitch changes. This also makes the main lift rotor 2 lighter, contributing to miniaturization and improved reliability. Furthermore, the tilt rotor 9 provides additional maneuverability and the ability to control roll and pitch angles.

[0054] Fuselage 1 can be made of carbon fiber, increasing its structural strength while reducing its weight. Specifically, fuselage 1 is composed of multiple layers of fiberboard. Any two layers of fiberboard are connected by multiple, evenly spaced support rods. This design makes the fuselage lighter, provides more space for other components, and facilitates the routing of wiring for the corresponding components. Specifically, servo 6 can be mounted on any fiberboard in the middle layer of fuselage 1.

[0055] A power source, such as a battery, may be provided on the fuselage 1 and may be mounted on any fiberboard located in the middle layer of the fuselage 1 or on the lower surface of the fuselage 1. The power source is electrically connected to the first motor 4, the servo 6, and the second motor 8 to provide electrical energy to these components.

[0056] A controller may also be provided on the fuselage 1. For example, the controller may be mounted on any fiberboard located in the middle layer of the fuselage 1, or on the lower surface of the fuselage 1. The controller is electrically connected to the first motor 4, the servo 6, and the second motor 8 to output control commands to these components. The controller is also configured to communicate with a remote control device to receive control commands sent by an operator via the remote control device.

[0057] Each main lift rotor assembly and each tilt rotor assembly of the composite aircraft of the embodiment of the present utility model can be controlled by a separate conventional controller. The composite aircraft can adopt a common six-rotor control method to achieve flight control, or adopt a common tilt rotor control method to achieve flight control, without the need to develop a special multi-rotor joint controller or control method for this aircraft. Specifically, each main lift rotor assembly can be controlled by a separate controller, that is, each first motor 4 is provided with a separate controller, and there is no need for multiple main lift rotor assemblies to be jointly controlled. Specifically, each tilt rotor assembly can be controlled by a separate controller, that is, each servo 6 is provided with a separate controller, and each second motor 8 is provided with a separate controller, and there is no need for multiple tilt rotor assemblies to be jointly controlled.

[0058] The high-strength carbon fiber plate used in the fuselage 1 can protect important components of the aircraft such as the power source and controller.

[0059] In addition, in addition to installing the load 3 on the upper end of the hollow support column 2 as mentioned above, some loads can also be installed on the fuselage, for example, on any fiberboard located in the middle layer of the fuselage 1.

[0060] The underside of the fuselage 1 is mounted with a landing gear 12, which provides support on the landing surface during takeoff and landing, cushioning the impact of landing. It should be understood that the landing gear 12 has a symmetrical structure to ensure stability. Preferably, the landing gear 12 is foldable, allowing for height adjustment to better suit the operating space. Furthermore, any additional payload required to be carried by the composite aircraft can also be mounted on the landing gear 12.

[0061] By cooperating with the main lift rotor assembly and the tilt rotor assembly, the composite aircraft can achieve hovering or vertical take-off and landing, level flight, and disabled flight modes. Taking four tilt rotors 9 as an example, two common flight states are described as follows:

[0062] 1) Hovering or vertical take-off and landing state: Figure 4 As shown, the main lift rotor 5 provides lift, while the servo 6 drives the tilt-rotor 9 upward, which rotates at low speed to control attitude. The attitude control mode at this point is the same as that of a conventional quadrotor. Under ideal conditions (correctly balanced center of gravity and no disturbances), the tilt-rotor 9 does not require auxiliary adjustment during vertical takeoff and landing and fixed-point hovering.

[0063] 2) Level flight state: Figure 5 and 6 As shown, the main lift rotor 5 provides lift, while the two servos 6 on the opposite sides drive the corresponding tilt rotors 9 to tilt in the forward direction to provide lateral force and control attitude. The remaining two tilt rotors 9 return to zero angle to control attitude. At this point, the hybrid aircraft is in a horizontal state, flying in the direction indicated by the tilted tilt rotors 9. In the absence of disturbances (no need to control roll attitude), the tilt angle of the two tilt rotors 9 should be close to 90°, only providing the lateral force required for flight to counteract wind resistance.

[0064] In addition, based on the above structural design, the composite aircraft of the embodiment of the utility model can achieve normal flight or minimum safety when part of the power system fails, such as Figure 7 As shown, the typical failure flight status is:

[0065] 1) At a minimum, one main lift rotor 5 and two tilt-rotors 9 are permitted to maintain normal flight. For example, if only one main lift rotor 5 and the first motor 4 are operational, and two tilt-rotors 9 fail, the operational main lift rotor 5 provides lift, while the remaining two functioning tilt-rotors 9 control attitude. The two functioning tilt-rotors 9 tilt a certain angle and rotate at high speed, using the horizontal component of thrust to offset the counter-torque of the main lift rotor 5, while using the vertical component of thrust to control flight attitude.

[0066] 2) Using only a single main lift rotor 5 and a single tilt rotor 9 to maintain altitude and heading, the aircraft can self-stabilize its speed within a narrow range, enabling stable and controlled flight to the target landing site for parachute deployment or autospin landing. This operating mode minimizes the possibility of damage. If four main lift rotors 5 are used, the composite aircraft with this structure can ensure safe operation even with up to 75% of its powertrain failures.

[0067] At the same time, combined with the above basic flight modes, more redundant flight modes can be achieved by increasing the number of main lift rotors 5 and first motors 4.

[0068] In addition, under the structure of the above-mentioned composite aircraft, considering the actual application scenario, the composite aircraft is designed to be foldable to facilitate actual transportation and plug-and-play on site. Figure 8 and Figure 9 The storage and transportation methods of the composite aircraft according to the embodiment of the present invention are described.

[0069] Figure 8 The hybrid aircraft of this embodiment is shown in its single-unit stowed transport configuration. The two main lift rotors 5 can be folded together, while the spacing between the tilt-rotors 9 can be adjusted circumferentially within the horizontal plane. The landing gear 12 can also be adjusted in height to meet the required height requirements for transport.

[0070] Further, if Figure 9 As shown, for multiple composite aircraft, Figure 8 Based on the above single-machine storage method, multiple composite aircraft can be stored. The main lift rotors 5 can be arranged in parallel, and the tilt rotors 9 can be adjusted to allow multiple composite aircraft to be placed side by side, thus minimizing the transportation space.

[0071] Experiments were conducted on the composite aircraft according to the embodiment of the present invention. The experimental results show that the composite aircraft according to the embodiment of the present invention has good endurance parameters. The specific test data are as follows:

[0072] When the aircraft is not equipped with the main lift rotor 5, the first motor 4 and the hollow support column 3, and only relies on the four tilt rotors 9 to fly, the aircraft weight is measured to be 750 grams and the hovering power is 115 watts. When the main lift rotor 5, the first motor 4 and the hollow support column 3 are installed, the aircraft weight increases to 2030 grams, but the hovering power is reduced to 83 watts. The test power curve is as follows Figure 10 As shown, it is shown that the composite aircraft of the embodiment of the utility model is feasible and has higher operating efficiency and endurance time in actual flight.

[0073] In summary, the composite aircraft of the embodiment of the present invention has the following beneficial effects:

[0074] 1. Hovering and low-speed flight are more efficient. Due to the special structure of the aircraft, the large main lift rotor can improve hovering efficiency. In horizontal flight, the incoming airflow is parallel to the main lift rotor, and the attitude tilt rotor provides the power required for forward flight. The airflow is lateral to the main lift rotor, which can increase the efficiency of the main lift rotor. The downwash airflow of the main lift rotor is also lateral to the tilt rotor that provides lateral thrust, which can also increase the efficiency of the tilt rotor.

[0075] 2. Higher safety. Multiple tilt-rotors can switch between different modes, improving the redundancy of system operation and reducing the probability of crashes. When a main lift rotor fails, the remaining main lift rotors can provide full lift, and the tilt of the tilt-rotors can efficiently provide reverse torque to maintain normal flight. These operating modes are not possible with traditional multi-rotors or helicopters. In addition, the proposed composite aircraft does not contain complex structures such as hinges and variable pitch, and the failure risk and maintenance cost of individual components are low.

[0076] 3. Low flight noise. The composite tilt-rotor aircraft designed in this embodiment has high rotor efficiency, resulting in less total energy converted into sound. Field measurements show that the main lift rotor of a 2kg aircraft rotates at less than 6 rps, and the primary noise frequency is less than 20Hz, which is outside the human hearing range. Furthermore, the high-frequency component of the noise emitted is significantly lower than that of traditional multi-rotors, reducing human discomfort in practical applications.

[0077] 4. Smoother flight with minimal impact on payload. Changing flight speed does not require simultaneously changing the aircraft's attitude, thus reducing payload disturbances. This facilitates the stable operation of precision equipment (such as camera gimbals and measuring equipment) and prevents spillage of liquid payloads (e.g., liquids). Furthermore, the faster response and higher sensitivity of small tilt-rotors can better suppress the impact of external disturbances (such as airflow changes) on the aircraft and payload.

[0078] 5. Lower dead weight helps improve flight time. The dead weight of the composite aircraft is lower than other comparison solutions, which allows the composite aircraft to be made lighter or use larger rotors at the same weight, thereby achieving higher hovering efficiency.

[0079] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor, characterized in that: include: a fuselage, a hollow support column, at least two main lift rotor assemblies, and at least two tilt rotor assemblies; The lower end of the hollow support column is fixedly arranged on the upper surface of the fuselage, and the upper end of the hollow support column is used to install the load; Each of the main lift rotor assemblies includes: a first motor and a main lift rotor, wherein the first motor is mounted on the hollow support column, and the main lift rotor is sleeved on the hollow support column, and the first motor is connected to the main lift rotor to drive the main lift rotor to rotate around the hollow support column; two adjacent main lift rotors are spaced apart; Each of the tilt-rotor assemblies includes: a steering gear, a rotating shaft, a second motor, and a tilt-rotor, wherein the output shaft of the steering gear is connected to one end of the rotating shaft to drive the rotating shaft to rotate; the second motor is mounted on the other end of the rotating shaft, and the second motor is connected to the tilt-rotor to drive the tilt-rotor to rotate; the steering gear of each tilt-rotor assembly is mounted on the fuselage so that the rotating shaft of each tilt-rotor assembly extends outward from the side of the fuselage, and the angle between any two adjacent rotating shafts is the same; The size of the main lift rotor is larger than that of the tilt rotor, so that the plurality of tilt rotors are located directly below the main lift rotor.

2. The composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor according to claim 1, characterized in that: The fuselage is composed of multiple layers of fiberboard, and any two layers of the fiberboard are connected by multiple support rods with uniform intervals.

3. The composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor according to claim 2, characterized in that: The servo is mounted on any fiberboard located in the middle layer of the fuselage.

4. The composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor according to claim 1, characterized in that: The landing gear is installed on the lower surface of the fuselage.

5. The composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor according to claim 4, characterized in that: The landing gear is a foldable landing gear.

6. The composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor according to claim 1, characterized in that: A power source is provided on the fuselage, and the power source is electrically connected to the first motor, the steering gear and the second motor.

7. The composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor according to claim 1, characterized in that: A controller is provided on the fuselage, and the controller is electrically connected to the first motor, the steering gear and the second motor.

8. The composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor according to claim 1, characterized in that: There are two main lift rotor assemblies, and the two main lift rotors rotate forward and reverse at a differential speed.

9. The composite aircraft integrating coaxial multi-rotor and tilt-multi-rotor according to claim 1, characterized in that: The number of the tilt rotor assemblies is four.

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