Modular combined unmanned aerial vehicle and control method thereof

Abstract

The invention discloses a modular combined unmanned aerial vehicle and a control method thereof, and relates to the field of unmanned aerial vehicle design, and the modular combined unmanned aerial vehicle comprises a fuselage, a control system, a duct module and a folding paddle module; the duct module is mounted on the aircraft body, provides lift force for the whole aircraft and guarantees the maneuvering characteristics of the whole aircraft; the folding paddle module is mounted on the duct module, provides additional flight power for the fuselage, and adopts a passive folding design; the control system comprises a sensor and a flight control frame; the sensor and the flight control frame are installed on the fuselage, the sensor can obtain surrounding environment information, and the flight control frame can control operation of the duct module and the folding paddle module according to the environment information, so that flight mode switching is achieved. According to the invention, control strategies can be automatically switched according to environmental conditions so as to adapt to indoor stability requirements and outdoor flexibility requirements.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle design, and more particularly to a modular combined unmanned aerial vehicle and its control method. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] In recent years, ducted multi-rotors and open-prop multi-rotors, as two major representatives of multi-rotor unmanned aerial vehicles, have experienced an exponential growth period in theoretical research and actual product development. Ducted multi-rotors use ducted rings to enhance lift reserves and protect the propellers, while open-prop multi-rotors excel in stability and wind resistance. They are respectively suitable for indoor and outdoor environments, but face their own challenges when flying across domains. To address the complexity of indoor and outdoor flight environments, variable-structure cross-domain unmanned aerial vehicles have emerged, with the ability to flexibly adapt to different environments, including open outdoor spaces and narrow indoor areas. However, variable-structure cross-domain unmanned aerial vehicles usually have complex structures, high manufacturing costs, and challenges and limitations in terms of design, maintenance, and performance. For example, Chinese Patent No. CN106628154A discloses a multi-rotor unmanned aerial vehicle with a dual-rotor system, having a main rotor and four secondary rotors. The main rotor provides lift for the unmanned aerial vehicle, and by controlling the rotational speeds of the respective secondary rotors, different thrusts are generated by the secondary rotors to facilitate steering. However, they all have an open-prop structure, are not easy to pass through narrow spaces, and are prone to touching obstacles and being damaged. Chinese Patent No. CN209600792U discloses a variable-size propeller, which can change the size of the propeller through a torsion spring, thereby changing the output. However, it is only applicable to small fixed-wing unmanned aerial vehicles and has a relatively small range of use.

[0004] Currently, due to the ducted system included in the design of ducted unmanned aerial vehicles, it can effectively concentrate and guide the airflow. Furthermore, it can provide stable lift and reduce the dependence on the external space flow. At the same time, it can protect the propellers, enabling them to fly in a smaller environment without worrying about the collision of the propellers with the external environment. However, ducted unmanned aerial vehicles are relatively small in size, have limited power outdoors, and have a large lateral windward area, resulting in relatively large wind disturbance forces, which affect stability. While open-prop unmanned aerial vehicles can utilize the large space and wind outdoors to enhance lift and maneuverability, they have no protection indoors. At the same time, the unfolded size of the high-power propeller blades is too large and is prone to touching obstacles and being damaged. Summary of the Invention

[0005] The purpose of the present invention is to design a modular combined unmanned aerial vehicle capable of realizing indoor and outdoor cross-domain flight, which can automatically switch control strategies according to environmental conditions to meet the stability requirements indoors and the flexibility requirements outdoors in view of the problems existing in the prior art.

[0006] The technical solution of the present invention is as follows:

[0007] A modular combined UAV, the modular combined UAV having a composite configuration of a ducted rotor and a folding open rotor, specifically comprising:

[0008] Fuselage, control system, duct module and folding propeller module;

[0009] The duct module is installed on the fuselage to provide lift for the whole aircraft and ensure its maneuverability;

[0010] The folding propeller module is installed on the duct module to provide additional flight power for the fuselage, and adopts a passive folding design;

[0011] The control system includes: a sensor and a flight control frame; the sensor and the flight control frame are installed on the fuselage, the sensor can obtain surrounding environmental information, and the flight control frame can control the operation of the duct module and the folding propeller module according to the environmental information, thereby realizing flight mode switching.

[0012] Furthermore, the duct module comprises:

[0013] A duct, a rotor and a ducted rotor motor; the duct is connected to the fuselage through a ducted adapter shaft, and the rotor is installed in the duct through the ducted rotor motor.

[0014] Furthermore, there are four duct modules in total, which are respectively arranged on both sides of the fuselage.

[0015] Furthermore, the folding paddle module includes: a power drive assembly and a power assembly; the power assembly is installed on the duct ring through the power drive assembly.

[0016] Furthermore, the power drive assembly includes: a mounting base, the mounting base has a built-in electric adjustment system for controlling the power assembly, the power assembly is mounted on the mounting base, and the mounting base is mounted on the duct ring through the duct ring mounting base.

[0017] Furthermore, the power assembly includes: an open rotor motor and a propeller assembly, the open rotor motor is mounted on a mounting base via an open rotor motor bracket, and the propeller assembly is connected to the open rotor motor.

[0018] Furthermore, a quick plug-in structure is provided on the folding paddle module, and the plug-in and pull-out functions of the folding paddle module are realized through the quick plug-in structure.

[0019] Furthermore, the quick plug-in / pull-out structure includes: a blade connector and an automatic locking buckle.

[0020] Further, the sensor includes a lidar and a pan-tilt camera, which are installed at two positions, front and back, on the fuselage.

[0021] Further, the flight control framework includes a ducted rotor mode controller, a power enhancement mode controller, a control distribution module, and controllers corresponding to each ducted rotor motor and open rotor motor;

[0022] Both the ducted rotor mode controller and the power enhancement mode controller include a position controller and an attitude controller;

[0023] The control distribution module includes a ducted rotor mode distribution module, a power enhancement mode distribution module, and a mode switching module;

[0024] In the ducted rotor mode, the flight control framework receives the desired yaw angle ψ and the desired position p as inputs. The position controller in the ducted rotor mode controller calculates the desired pitch angle θ 1 , roll angle φ 1 and the desired total thrust F 1 . The attitude controller in the ducted rotor mode controller calculates the desired moment M 1 according to the desired yaw angle ψ and the pitch angle θ 1 , roll angle φ 1 ; The desired moment M 1 and the desired total thrust F 1 are converted into the desired rotational speed ω 1 through the ducted rotor mode distribution module;

[0025] In the power enhancement mode, the flight control framework also receives the desired yaw angle ψ and the desired position p. The position controller in the power enhancement mode controller calculates the desired pitch angle θ 2 , roll angle φ 2 and the desired total thrust F 2， The attitude controller in the power enhancement mode controller calculates the desired moment M 2 according to the desired yaw angle ψ and the pitch angle θ 2 , roll angle φ 2 ; The desired moment M 2 and the desired total thrust F 2 are converted into the desired rotational speed ω 2 through the power enhancement mode distribution module;

[0026] The flight mode switching includes switching between the ducted rotor mode and the power enhancement mode;

[0027] When in the ducted rotor mode, the ducted rotor mode controller operates. The desired rotational speed obtained through the ducted rotor mode distribution module is output to the controllers corresponding to each ducted rotor motor via the mode switching module, and the respective desired throttle commands are output.

[0028] When in the power enhancement mode, the power enhancement mode controller operates. The desired rotational speed obtained through the power enhancement mode distribution module is output to the controllers corresponding to each ducted rotor motor and the open rotor motor via the mode switching module, and the respective desired throttle commands are output.

[0029] The present invention also proposes a control method for a modular combined unmanned aerial vehicle, used to control the above-mentioned modular combined unmanned aerial vehicle, including:

[0030] In the ducted rotor mode, the flight control framework receives the desired yaw angle ψ and the desired position p as inputs. The desired pitch angle θ 1 , roll angle φ 1 and the desired total thrust F 1 are calculated by the position controller in the ducted rotor mode controller. The attitude controller in the ducted rotor mode controller calculates the desired moment M 1 according to the desired yaw angle ψ and the pitch angle θ 1 , roll angle φ 1 ; The desired moment M 1 and the desired total thrust F 1 are converted into the desired rotational speed ω 1 through the ducted rotor mode distribution module;

[0031] In the power enhancement mode, the flight control framework also receives the desired yaw angle ψ and the desired position p. The desired pitch angle θ 2 , roll angle φ 2 and the desired total thrust F 2 are calculated by the position controller in the power enhancement mode controller. The attitude controller in the power enhancement mode controller calculates the desired moment M 2 according to the desired yaw angle ψ and the pitch angle θ 2 , roll angle φ 2 ; The desired moment M 2 and the desired total thrust F 2 are converted into the desired rotational speed ω 2 through the power enhancement mode distribution module;

[0032] When in the ducted rotor mode, the ducted rotor mode controller operates. The desired rotational speed obtained through the ducted rotor mode distribution module is output to the controllers corresponding to each ducted rotor motor via the mode switching module, and the respective desired throttle commands are output.

[0033] When in the power enhancement mode, the power enhancement mode controller works, and the desired rotational speed obtained through the power enhancement mode distribution module is output to the controllers corresponding to each ducted rotor motor and open rotor motor through the mode switching module, and the respective desired throttle commands are output.

[0034] Compared with the existing technologies, the beneficial effects of the present invention are as follows:

[0035] 1. The present invention provides a modular combined unmanned aerial vehicle, adopting a composite configuration of ducted rotors and folding open rotors to achieve cross-domain maneuverability.

[0036] 2. The present invention provides a quick-release structure for open rotors. Through the introduction of a quick plug-and-play mechanism, this design significantly improves the wind resistance and flight stability of the unmanned aerial vehicle during outdoor flight. In scenarios where cross-domain high maneuverability is not required, the open rotors can be removed to improve the indoor maneuverability and endurance of the unmanned aerial vehicle. At the same time, cross-domain flight capabilities indoors and outdoors are achieved. This structural design is simple, has a low manufacturing cost, and the installation and disassembly processes are simple.

[0037] 3. The present invention proposes a cross-domain maneuvering process and a mode switching control method, which can achieve rapid conversion between four rotors and eight rotors. This method enables flexible selection of using four rotors or eight rotors under different mission requirements and environmental conditions, thereby enhancing the adaptability of the system. At the same time, this control method also significantly improves flight safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a diagram of the outdoor flight of the modular combined unmanned aerial vehicle of this application;

[0039] Figure 2 It is a diagram of the indoor flight of the modular combined unmanned aerial vehicle of this application;

[0040] Figure 3 It is a schematic diagram of the ducted fuselage module of the modular combined unmanned aerial vehicle of this application;

[0041] Figure 4 It is a schematic diagram of the folding propeller module of the modular combined unmanned aerial vehicle of this application;

[0042] Figure 5 It is a schematic diagram of the mounting base of this application;

[0043] Figure 6 It is a schematic diagram of the multi-modal dynamic switching control framework of the modular combined unmanned aerial vehicle of this application.

[0044] Reference Numerals: 1 - fuselage, 2 - folding propeller module, 3 - ducted fan module, 4 - lidar, 5 - ducted fan adapter shaft, 6 - ducted fan rotor motor, 7 - ducted fan ring, 8 - rotor, 9 - gimbal camera, 10 - ducted fan ring mounting base, 11 - open rotor motor, 12 - open rotor motor bracket, 13 - mounting base, 14 - propeller assembly, 15 - socket, 16 - automatic locking buckle. Detailed Embodiment

[0045] It should be noted that relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0046] The features and performance of the present invention will be further described in detail below in conjunction with the embodiments.

[0047] Embodiment 1

[0048] This embodiment proposes a modular combined unmanned aerial vehicle with a composite configuration of ducted fan rotors and folding open rotors, which can realize the conversion between ducted fan rotors and folding open rotors according to the environment, so as to achieve cross-domain maneuvering flight indoors and outdoors, improve the flight stability outdoors and the passability indoors. During the cross-domain flight process, the surrounding environmental information is obtained through sensors to determine the flight mode, the flight mode is switched through the control system, and at the same time, by setting the corresponding mixing control matrix and switching switches, the mutual switching between the quadrotor and the octocopter is controlled to achieve multi-modal control. In order to facilitate modular combination, a quick-release structure for the open rotor is designed to remove the open rotor when there is no need for cross-domain high-maneuver scenarios, improving the indoor maneuverability and endurance of the unmanned aerial vehicle;

[0049] Please refer to Figures 1-5 , the specific structure of a modular combined unmanned aerial vehicle proposed in this embodiment includes:

[0050] Fuselage 1, control system, ducted fan module 3 and folding propeller module 2; preferably, the fuselage 1 is a carbon fiber fuselage 1; the specific type of the control system is as Figure 6 shown;

[0051] The ducted fan module 3 is installed on the fuselage 1, providing lift for the whole aircraft and ensuring its maneuverability;

[0052] The folding propeller module 2 is installed on the ducted fan module 3, providing additional flight power for the fuselage 1. It adopts a passive folding design, which can improve the aerodynamic efficiency and lift reserve in an outdoor unconstrained environment, and does not increase the external dimensions of the ducted fuselage 1 in an indoor constrained environment to ensure passability. In scenarios where cross-domain high-maneuver operations are required, the open propeller mode is enabled to enhance power output. In a conventional flight environment, the rotors 8 can be folded to optimize flight endurance and improve passability;

[0053] The control system includes: sensors and a flight control framework; the sensors and the flight control framework are installed on the aircraft 1. The sensors can obtain the surrounding environmental information, and the flight control framework can control the operation of the ducted fan module 3 and the folding propeller module 2 according to the environmental information, thereby realizing flight mode switching.

[0054] In this embodiment, specifically, the ducted fan module 3 includes:

[0055] A ducted fan ring 7, rotors 8, and a ducted fan rotor motor 6; the ducted fan ring 7 is connected to the fuselage 1 through a ducted fan adapter shaft 5, and the rotors 8 are installed in the ducted fan ring 7 through the ducted fan rotor motor 6. It should be noted that the rotors 8 are the ducted propellers, and compared with open rotors 8 of the same diameter, they will generate greater thrust under the same power consumption.

[0056] In this embodiment, specifically, there are four ducted fan modules 3, which are respectively arranged on both sides of the fuselage 1.

[0057] In this embodiment, specifically, the folding propeller module 2 includes: a power drive assembly and a power assembly; the power assembly is installed on the ducted fan ring 7 through the power drive assembly.

[0058] In this embodiment, specifically, the power drive assembly includes: a mounting base 13, which is internally provided with an electronic speed control system for controlling the power assembly. The power assembly is installed on the mounting base 13, and the mounting base 13 is installed on the ducted fan ring 7 through the mounting base 13 of the ducted fan ring 7, and its design is convenient for disassembly and installation on the outside of the ducted fan.

[0059] In this embodiment, specifically, the power assembly includes an open-rotor motor 11 and a propeller assembly 14. The open-rotor motor 11 is mounted on a mounting base 13 through an open-rotor motor bracket 12 (i.e., a fixture), and the propeller assembly 14 is connected to the open-rotor motor 11. This design ensures that the power assembly is firmly fixed during flight, avoiding the situation of blade detachment. It should be noted that due to different ducted tilt angles, the angle of the open-rotor motor 11 will be adjusted accordingly to ensure that the blades of the open propeller remain horizontal.

[0060] In this embodiment, specifically, the folding propeller module 2 is provided with a quick plug-and-play structure, and the efficient plug-and-play function of the folding propeller module 2 is realized through the quick plug-and-play structure.

[0061] In this embodiment, specifically, the quick plug-and-play structure includes a blade connector and an automatic locking buckle 16. It should be noted that the blade connector is arranged inside the open-rotor motor bracket 12 and is directly connected to the open-rotor motor 11. A socket 15 matching the blade connector is arranged on the mounting base 13. The automatic locking buckle 16 is arranged outside the open-rotor motor bracket 12, and the mounting base 13 is provided with a matching structure to firmly fix the open-rotor motor bracket 12 on the mounting base 13. At the same time, the blade connector inside the open-rotor motor bracket 12 is closely connected to the socket 15, ensuring the stability of signal transmission and power supply. Particularly worth mentioning is that considering the diversity of ducted tilt angles, the angle of the open-rotor motor bracket 12 can be adaptively adjusted accordingly, effectively ensuring that the blades of the open propeller are always in a horizontal state, optimizing flight performance and efficiency.

[0062] Specifically, the mounting base 13 is fixed to the outside of the ducted ring 7 through screws and nuts. This mounting method ensures that it can be disassembled and installed conveniently and quickly, providing a basis for the flexible use of the overall module. The electronic speed control system is installed below the mounting base 13, and the socket 15 equipped on the mounting base 13 undertakes the important task of connecting the open-rotor motor 11 and the electronic speed control system. When the blade connector is inserted, it can automatically trigger the mechanical locking mechanism, thus ensuring the stable realization of the power supply and communication functions of the open-rotor motor 11. The blade connector is located inside the open-rotor motor bracket 12 and is directly connected to the open-rotor motor 11 to drive the rotation of the propeller assembly 14 (a two-blade propeller in this embodiment) to achieve power output.

[0063] In this embodiment, specifically, the sensor includes a lidar 4 and a gimbal camera 9. The lidar 4 and the gimbal camera 9 are installed at two positions in the front and rear of the fuselage 1.

[0064] In this embodiment, specifically, the flight control framework includes: a ducted rotor mode controller, a power enhancement mode controller, a control distribution module, and controllers corresponding to each ducted rotor motor and open rotor motor;

[0065] Both the ducted rotor mode controller and the power enhancement mode controller include a position controller and an attitude controller;

[0066] The control distribution module includes: a ducted rotor mode distribution module, a power enhancement mode distribution module, and a mode switching module;

[0067] In the ducted rotor mode, the flight control framework receives the desired yaw angle ψ and the desired position p as inputs. The position controller in the ducted rotor mode controller calculates the desired pitch angle θ 1 , roll angle φ 1 and the desired total thrust F 1 . The attitude controller in the ducted rotor mode controller calculates the desired moment M 1 according to the desired yaw angle ψ, pitch angle θ 1 , and roll angle φ 1 ; The desired moment M 1 and the desired total thrust F 1 are converted into the desired rotational speed ω 1 through the ducted rotor mode distribution module;

[0068] In the power enhancement mode, the flight control framework also receives the desired yaw angle ψ and the desired position p. The position controller in the power enhancement mode controller calculates the desired pitch angle θ 2 , roll angle φ 2 and the desired total thrust F 2 . The attitude controller in the power enhancement mode controller calculates the desired moment M 2 according to the desired yaw angle ψ, pitch angle θ 2 , and roll angle φ 2 ; The desired moment M 2 and the desired total thrust F 2 are converted into the desired rotational speed ω 2 through the power enhancement mode distribution module;

[0069] The flight mode switching includes: switching between the ducted rotor mode and the power enhancement mode;

[0070] When in the ducted rotor mode, the ducted rotor mode controller works at this time. The desired rotational speed obtained through the ducted rotor mode distribution module is output to the controllers corresponding to each ducted rotor motor through the mode switching module, and the respective desired throttle commands are output;

[0071] When in the power boost mode, at this time the power boost mode controller works, and the desired rotational speed obtained through the power boost mode distribution module is output to the controllers corresponding to each ducted rotor motor and open rotor motor through the mode switching module, and respective desired throttle commands are output.

[0072] Please refer to Figure 6 , this embodiment also proposes a control method for a modular combined unmanned aerial vehicle, used to control the above-mentioned modular combined unmanned aerial vehicle, including:

[0073] In the ducted rotor mode (i.e., the quadcopter mode), the flight control framework receives the desired yaw angle ψ and the desired position p as inputs, and calculates the desired pitch angle θ 1 , roll angle φ 1 and the desired total lift force F 1 through the position controller in the ducted rotor mode controller. The attitude controller in the ducted rotor mode controller calculates the desired moment M 1 according to the desired yaw angle ψ and the pitch angle θ 1 , roll angle φ 1 ; the desired moment M 1 and the desired total lift force F 1 are converted into the desired rotational speed ω 1 through the ducted rotor mode distribution module;

[0074] In the power boost mode (i.e., the octocopter mode), the flight control framework also receives the desired yaw angle ψ and the desired position p, and calculates the desired pitch angle θ 2 , roll angle φ 2 and the desired total lift force F 2 through the position controller in the power boost mode controller. The attitude controller in the power boost mode controller calculates the desired moment M 2 according to the desired yaw angle ψ and the pitch angle θ 2 , roll angle φ 2 ; the desired moment M 2 and the desired total lift force F 2 are converted into the desired rotational speed ω 2 through the power boost mode distribution module;

[0075] The flight mode switching includes: switching between the ducted rotor mode and the power boost mode;

[0076] When in the ducted rotor mode, the ducted rotor mode controller works at this time. The desired rotational speed obtained through the ducted rotor mode distribution module is output to the controllers corresponding to each ducted rotor motor through the mode switching module, and the respective desired throttle commands are output; that is, only the rotor 8 works at this time. The desired rotational speeds 1-1 to 1-4 output by the mode switching module are input to the respective ducted rotor motor controllers to obtain the respective desired throttle commands, and the desired rotational speeds 2-1 to 2-4 are all output as 0;

[0077] When in the power enhancement mode, the power enhancement mode controller works at this time. The desired rotational speed obtained through the power enhancement mode distribution module is output to the controllers corresponding to each ducted rotor motor and the open rotor motor through the mode switching module, and the respective desired throttle commands are output;

[0078] It should be noted that the switching between the two modes is determined by selecting the corresponding controller. In the actual operation process, in the autonomous motion mode, the sensor receives external information, judges the environment at this time to select the appropriate mode, and performs autonomous switching; when in the remote control mode, the operator can set the corresponding channels on the remote control to switch the mode, realizing the quick switching between the two modes with one key. The entire framework realizes the smooth transition between the ducted rotor mode and the power enhancement mode through the mode switching mechanism, ensuring the flexibility and adaptability of the flight control system. Through precise control distribution, the system can effectively manage the flight power and meet the performance requirements under different flight conditions.

[0079] In this embodiment, it should also be noted that during the mode switching process, there is actually an intermediate mode, specifically as follows:

[0080] In the control distribution module, both modes adopt the distribution method of an octocopter to obtain the desired rotational speed, and then the mode switching module is used to select which mode's output rotational speed is transmitted to each motor controller;

[0081] The relationship between the thrust and torque and the rotational speed is:

[0082]

[0083] where F is the desired thrust, M x 、M y 、M z are the components of the desired torque M in the x, y, and z directions, c T1 is the thrust coefficient of the propeller in the duct, c M1 is the torque coefficient of the propeller in the duct, c T2 is the thrust coefficient of the open propeller, c M2 is the torque coefficient of the open propeller, d i-j is the distance between the i-jth motor and the center of the airframe, is the angle between the line connecting the motor center and the airframe center and the airframe O b x b axis, and δ i-j = (-1) i+1 , where i = 1, 2; j = 1, 2, 3, 4;

[0084] At this time, the control efficiency matrix of the octocopter is M 8 :

[0085]

[0086] When in the quadcopter state, set all columns after the fourth column to 0, that is:

[0087]

[0088] After that, the control allocation matrix P is obtained by solving the pseudo-inverse 8 , so as to allocate the rotational speeds to each motor; The rotational speeds of each motor output by the ducted rotor controller or the power enhancement mode controller are selected through mode switching.

[0089] A kind of allocation matrix P is obtained 8 which is expressed as follows:

[0090]

[0091] The above-described embodiments only represent the specific implementation manners of the present application, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation to the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application.

[0092] This background technology section is provided to generally present the context of the present invention. The work of the currently named inventors, the work to the extent described in this background technology section, and aspects that are not prior art at the time of filing this application are neither expressly nor impliedly admitted to be prior art of the present invention.

Claims

1. A modular combination drone, characterized in that: The modular combined UAV has a composite configuration of a ducted rotor and a folding open rotor, specifically including: A fuselage (1), a control system, a duct module (3) and a folding propeller module (2); The duct module (3) is installed on the fuselage (1) to provide lift for the whole aircraft and ensure its maneuverability; The foldable propeller module (2) is installed on the duct module (3) to provide additional flight power for the fuselage (1) and adopts a passive foldable design; The control system comprises: a sensor and a flight control frame; the sensor and the flight control frame are installed on a fuselage (1); the sensor can obtain surrounding environmental information; and the flight control frame can control the operation of a duct module (3) and a folding propeller module (2) according to the environmental information, thereby realizing flight mode switching.

2. A modular combined UAV according to claim 1, characterized in that: The duct module (3) comprises: A duct (7), a rotor (8) and a ducted rotor motor (6); the duct (7) is connected to the fuselage (1) via a ducted adapter shaft (5), and the rotor (8) is installed in the duct (7) via the ducted rotor motor (6).

3. A modular combined UAV according to claim 2, characterized in that: There are four duct modules (3) in total, which are respectively arranged on both sides of the fuselage (1).

4. A modular combined UAV according to claim 3, characterized in that: The folding paddle module (2) comprises: a power drive assembly and a power assembly; the power assembly is installed on the duct ring (7) through the power drive assembly.

5. A modular combined UAV according to claim 4, characterized in that: The power drive assembly comprises: a mounting base (13), the mounting base (13) having a built-in electric adjustment system for controlling the power assembly, the power assembly being mounted on the mounting base (13), and the mounting base (13) being mounted on the duct ring (7) via the mounting base (13).

6. A modular combined UAV according to claim 5, characterized in that: The power assembly comprises: an open rotor motor (11) and a propeller assembly (14); the open rotor motor (11) is mounted on a mounting base (13) via an open rotor motor bracket (12); and the propeller assembly (14) is connected to the open rotor motor (11).

7. A modular combined UAV according to claim 5, characterized in that: The folding paddle module (2) is provided with a quick plug-in structure, and the plug-in and pull-out functions of the folding paddle module (2) are realized through the quick plug-in structure.

8. A modular combined UAV according to claim 7, characterized in that: The quick plug-in / pull-out structure comprises a blade connector and an automatic locking buckle (16).

9. The modular combined UAV according to claim 6, characterized in that: The flight control framework includes: a ducted rotor mode controller, a power enhancement mode controller, a control distribution module, and controllers corresponding to each ducted rotor motor and open rotor motor; The ducted rotor mode controller and the power enhancement mode controller both include a position controller and an attitude controller; The control distribution module includes: a ducted rotor mode distribution module, a power enhancement mode distribution module and a mode switching module; In the ducted rotor mode, the flight control framework receives the desired yaw angle ψ and the desired position p as inputs, and calculates the desired pitch angle θ1, roll angle φ1 and the desired total thrust F1 through the position controller in the ducted rotor mode controller. The attitude controller in the ducted rotor mode controller calculates the desired torque M1 according to the desired yaw angle ψ, pitch angle θ1 and roll angle φ1; the desired torque M1 and the desired total thrust F1 are converted into the desired rotation speed ω1 through the ducted rotor mode allocation module; In the power enhancement mode, the flight control framework also receives the desired yaw angle ψ and the desired position p, and calculates the desired pitch angle θ2, roll angle φ2 and the desired total thrust F2 through the position controller in the power enhancement mode controller. The attitude controller in the power enhancement mode controller calculates the desired torque M2 according to the desired yaw angle ψ, pitch angle θ2 and roll angle φ2; the desired torque M2 and the desired total thrust F2 are converted into the desired rotation speed ω2 through the power enhancement mode distribution module; The flight mode switching includes: switching between a ducted rotor mode and a power enhancement mode; When in the ducted rotor mode, the ducted rotor mode controller works, and outputs the desired rotation speed obtained by the ducted rotor mode allocation module to the controller corresponding to each ducted rotor motor through the mode switching module, and outputs the respective desired throttle commands; When in power enhancement mode, the power enhancement mode controller works, and outputs the desired speed obtained by the power enhancement mode distribution module to the controllers corresponding to each ducted rotor motor and open rotor motor through the mode switching module, and outputs their respective desired throttle commands.

10. A control method for a modular combined drone, characterized in that: A modular combined drone for controlling any one of claims 1 to 9, comprising: In the ducted rotor mode, the flight control framework receives the desired yaw angle ψ and the desired position p as inputs, and calculates the desired pitch angle θ1, roll angle φ1 and the desired total thrust F1 through the position controller in the ducted rotor mode controller. The attitude controller in the ducted rotor mode controller calculates the desired torque M1 according to the desired yaw angle ψ, pitch angle θ1 and roll angle φ1; the desired torque M1 and the desired total thrust F1 are converted into the desired rotation speed ω1 through the ducted rotor mode allocation module; In the power enhancement mode, the flight control framework also receives the desired yaw angle ψ and the desired position p, and calculates the desired pitch angle θ2, roll angle φ2 and the desired total thrust F2 through the position controller in the power enhancement mode controller. The attitude controller in the power enhancement mode controller calculates the desired torque M2 according to the desired yaw angle ψ, pitch angle θ2 and roll angle φ2; the desired torque M2 and the desired total thrust F2 are converted into the desired rotation speed ω2 through the power enhancement mode distribution module; When in the ducted rotor mode, the ducted rotor mode controller works, and outputs the desired rotation speed obtained by the ducted rotor mode allocation module to the controller corresponding to each ducted rotor motor through the mode switching module, and outputs the respective desired throttle commands; When in power enhancement mode, the power enhancement mode controller works, and outputs the desired speed obtained by the power enhancement mode distribution module to the controllers corresponding to each ducted rotor motor and open rotor motor through the mode switching module, and outputs their respective desired throttle commands.

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