Foldable multi-rotor hybrid power unmanned transport plane

Abstract

The invention belongs to the technical field of unmanned aerial vehicles, and discloses a foldable multi-rotor hybrid power unmanned aerial vehicle which comprises lift rotors (10), attitude rotors (20), vehicle arms (30), a cabin (40), a photoelectric pod (50), a cargo hold (60) and an undercarriage (70). The lift rotors and the attitude rotors are combined, the attitude control difficulty is reduced while the large load is guaranteed, and compared with a traditional helicopter, the mechanical structure complexity is reduced, and maintenance and replacement are convenient; and when the power system is redundant, the reliability of the method is ensured through a system fault reconstruction scheme.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicles, and particularly relates to a foldable multi-rotor hybrid unmanned transport aircraft. Background Art

[0002] With the development of the form of war, the demand for various materials has been increasing continuously, and higher requirements have been put forward for the timeliness, flexibility and accuracy of logistics support; the continuously increasing war intensity and complex battlefield environment have greatly increased the difficulty of material delivery tasks. It is of practical significance to improve the existing logistics transportation methods and enhance the level of unmanned and intelligent.

[0003] With the continuous in-depth research on unmanned aerial vehicle technology in various countries around the world, unmanned aerial vehicles have been widely promoted and applied, and are being mass-equipped in the military and widely used in battlefield operations such as battlefield reconnaissance, electronic countermeasure, and precision strike. Their status and role are becoming more and more prominent. Unmanned aerial vehicles have the characteristics of being flexible, autonomously controllable, low-cost, and large payload, and have great development potential in the application of transportation and delivery, and are a good supplement to the existing transportation and delivery forces.

[0004] At present, most cargo-carrying unmanned aerial vehicles adopt fixed-wing configurations or helicopter configurations. However, fixed-wing aircraft do not meet the requirements of vertical takeoff and landing, and have poor transportability, and are difficult to quickly fold and unfold; helicopters need to adjust their attitudes by changing the pitch of the rotors, and the mechanical structure of the rotor disk is complex, which is not conducive to the maintenance or quick replacement of parts. Light unmanned aerial vehicles with multi-rotor configurations have simple mechanical structures and control systems, but there are still many deficiencies. For example, the "Albatross" unmanned transport aircraft, due to its pure electric form, has a short endurance time and cannot meet the transportation requirements over a relatively long distance; the "Cargo" unmanned aerial vehicle can meet the transportation requirements of large payload and long endurance, and can be transported by folding its arms, but since all four rotors are directly driven by a turboshaft engine, the transmission system has a large mass, the mechanical structure is complex, and the control flexibility is poor. At present, Kaman Corporation has only published the takeoff test flight video of the "Cargo" unmanned aerial vehicle, and no test flight experiments containing maneuvering actions have been published, which proves from the side that the attitude control of this unmanned aerial vehicle is difficult.

[0005] Therefore, it is necessary to study an unmanned transport aircraft with a simple mechanical structure, reliable endurance, and simple attitude control. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: to provide an unmanned transport aircraft with a simple mechanical structure, reliable endurance, and simple attitude control.

[0007] To solve the above technical problem, the specific technical solution of the present invention is as follows:

[0008] A foldable multi-rotor hybrid unmanned transport aircraft, comprising lift rotors 10, attitude rotors 20, arms 30, a cabin 40, an optoelectronic pod 50, a cargo hold 60, and landing gears 70;

[0009] The lift rotors 10 are coaxial rotors, installed at the central axis position on the upper part of the cabin 40; the lift rotors 10 include upper propellers 11, upper fixed hinges 12, lower propellers 13, lower fixed hinges 14, and lift rotor bases 15; the upper fixed hinges 12 and the lower fixed hinges 14 are installed vertically side by side on the lift rotor bases 15, the upper propellers 11 are installed on the upper fixed hinges 12, and the lower propellers 13 are installed on the lower fixed hinges 14; there is a 180° angle between the tips of the upper and lower propellers, and the rotating shafts of the upper and lower propellers enter the cabin from the lift rotor bases 15 and are connected to the reduction drive system;

[0010] Four groups of attitude rotors 20 are evenly distributed around the cabin 40 in an "X" layout. The four groups of attitude rotors 20 correspond to four arms 30. The arms 30 are used to connect the attitude rotors 20 and the cabin 40. Each arm 30 includes a connecting rod 31 and a folding hinge 32; one end of the folding hinge 32 is connected to the cabin 40, and the other end is connected to the connecting rod 31; by pushing the connecting rod 31, the folding hinge 32 drives the arm 30 to rotate, realizing the deployment and folding of the arm 30;

[0011] The cabin 40 is the core load-bearing structure of the whole machine, with an air inlet on the outside and airborne equipment installed inside;

[0012] The optoelectronic pod 50 is installed at the lower front position of the cabin 40; the cargo hold 60 is installed at the central bottom position of the cabin 40; the landing gears 70 are fixed to the bottom of the cabin 40 to play a supporting and buffering role.

[0013] Further, the folding hinge 32 is composed of a rotary hinge fixed to the cabin 40 and an eccentric locking pin. An angle limiter is provided inside the rotary hinge, which can realize the positioning and stopping of two states of 0° and 45°. The eccentric locking pin assembly is arranged outside the rotary hinge to realize the locking of the arm 30 in the deployed and folded states.

[0014] Further, the number of landing gears 70 is two, and they are fixed to the bottom of the cabin 40 in a symmetric arrangement.

[0015] Further, the landing gears 70 are fixed to the cabin 40 by welding.

[0016] Further, each group of attitude rotors 20 is provided with an independent motor.

[0017] Further, it also includes a series-parallel hybrid power device, which includes an energy management system, an engine, a battery pack, and a motor. The energy management system is used to distribute the power of the engine. A part of the power of the engine directly drives the lift rotor, and the remaining power supplies the battery pack and the motor through a generator.

[0018] Further, during operation, the battery pack first provides starting power for the engine, and the energy management system distributes the energy flow according to the state of charge of the battery pack and the power required on the propeller shaft.

[0019] Further, at low loads, there is some redundant power in the engine. The attitude rotor is mainly driven by the generator, and the redundant power is used to charge the battery pack. At high loads, the engine first ensures the operation of the lift rotor, the output power of the generator is low, and the attitude rotor is driven by both the generator and the battery pack.

[0020] Further, when the upper propeller 11 fails, the output of the lower propeller 13 decreases to reduce the reverse torque, and at the same time, the power of the attitude rotor increases.

[0021] Further, the internal airborne equipment includes a flight control equipment box 42, a fuel storage tank 43, a lubricating oil and cooling system 44, an aviation piston engine 45, a reduction and transmission system 46, a generator 47, a battery pack 48, and an exhaust port 49. The above components are symmetrically arranged along the longitudinal middle section of the cabin.

[0022] The present invention has the following advantages:

[0023] 1. The combination of the lift rotor and the attitude rotor reduces the difficulty of attitude control while ensuring a large load capacity. Compared with traditional helicopters, it reduces the complexity of the mechanical structure and is convenient for maintenance and replacement.

[0024] 2. The power system has redundancy, and the reliability of the present invention is ensured through a system fault reconstruction scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the top perspective view of the present invention.

[0026] Figure 2 is the longitudinal sectional view of the present invention.

[0027] Figure 3 is the bottom perspective view of the present invention.

[0028] Figure 4 is the unfolded and folded schematic diagram of the present invention.

[0029] Figure 5 is the schematic diagram of the hybrid power system architecture of the present invention.

[0030] Figure 6This is the fault reconstruction flow chart of the present invention.

[0031] In the figure: 10 - lift rotor, 20 - attitude rotor, 30 - arm, 40 - cabin, 50 - optoelectronic pod, 60 - cargo hold, 70 - landing gear, 11 - upper propeller, 12 - upper fixed hinge, 13 - lower propeller, 14 - lower fixed hinge, 15 - lift rotor base, 21 - rotor blade, 22 - fairing, 23 - motor, 31 - connecting rod, 32 - folding hinge, 41 - air intake, 42 - flight control equipment box, 43 - fuel storage tank, 44 - lubricating oil and cooling system, 45 - aviation piston engine, 46 - reduction and transmission system, 47 - generator, 48 - battery pack, 49 - exhaust port. Detailed implementation manners

[0032] In order to better understand the purpose, structure and function of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] As Figure 1 shown, a foldable multi-rotor hybrid unmanned transport aircraft provided in this embodiment is composed of a lift rotor 10, an attitude rotor 20, an arm 30, a cabin 40, an optoelectronic pod 50, a cargo hold 60 and a landing gear 70.

[0034] The lift rotor 10 is a coaxial rotor, installed at the central axis position on the upper part of the cabin 40, and is used to support the propeller and transmit power. This component is composed of an upper propeller 11, an upper fixed hinge 12, a lower propeller 13, a lower fixed hinge 14 and a lift rotor base 15. The upper propeller 11 is installed on the upper fixed hinge 12, the lower propeller 13 is installed on the lower fixed hinge 14, and the upper fixed hinge 12 and the lower fixed hinge 14 are installed on the lift rotor base 15.

[0035] The attitude rotor 20 is used to realize the attitude control and direction adjustment of the unmanned aircraft, including maneuvering actions such as forward flight and turning. The number of this component is 4 groups, and they are evenly distributed around the cabin 40 in an "X" layout. Each group of attitude rotors is respectively composed of a rotor blade 21, a fairing 22 and a motor 23. The arm 30 is used to connect the attitude rotor 20 and the cabin 40, and the number is 4. Each arm is composed of a connecting rod 31 and a folding hinge 32. The folding hinge 32 is composed of a rotating hinge fixed on the cabin 40 and an eccentric lock pin. An angle limiter is arranged inside the rotating hinge to realize the positioning and stopping of two states of 0° and 45°. The eccentric lock pin assembly is arranged outside the rotating hinge to realize the locking of the arm 30 in two states of unfolding and folding. One end of the folding hinge 32 is connected to the cabin 40, and the other end is connected to the connecting rod 31. By pushing the connecting rod 31, the folding hinge 32 drives the arm 30 to rotate, realizing the unfolding and folding of the arm 30.

[0036] The cabin 40 is the core load-bearing structure of the whole machine. An air intake 41 is arranged outside, and on-board equipment such asFigure 2 As shown, they are the flight control equipment box 42, fuel storage tank 43, lubricating oil and cooling system 44, aviation piston engine 45, reduction and transmission system 46, generator 47, battery pack 48, and exhaust port 49 respectively. Each component is symmetrically arranged along the longitudinal mid-section of the cabin. Among them, the number of fuel storage tanks 43 is 2, and the number of the other components is 1.

[0037] As Figure 3 shown, the optoelectronic pod 50 is installed at the lower front position of the cabin 40; the cargo hold 60 is installed at the central position of the bottom of the cabin 40; the number of landing gears 70 is 2, and they are symmetrically arranged and welded to the bottom of the cabin 40 to play a supporting and buffering role.

[0038] Specifically, the lift rotor adopts a coaxial dual-rotor layout form, and the upper and lower rotors rotate together to cancel the torque. The upper propeller 11 is connected to the hub through the upper fixed hinge 12, so as to be fixed on the rotating shaft; the lower propeller 13 is connected to the hub and the rotating shaft through the lower fixed hinge 14. To avoid aerodynamic interference, an included angle of 180° is set between the tips of the upper and lower propellers. The rotating shaft enters the cabin from the lift rotor base 15 and is connected to the reduction and transmission system.

[0039] The present invention uses the attitude rotor differential method of a multi-rotor unmanned aerial vehicle as an attitude control means. The 4 attitude rotors 20 are driven by motors 21, and the motors 21 are driven by the generator 47 and the battery pack 48. The electronic speed controllers of the motors receive the instructions of the flight control computer in the flight control equipment box 42 and adjust the voltage to control the speed. Taking forward flight as an example, the speeds of the two front attitude rotors are less than those of the two rear attitude rotors, then the fuselage tilts forward and obtains a forward velocity vector to achieve the purpose of forward flight. The principles of the other maneuver controls are the same as those of a classic four-rotor unmanned aerial vehicle.

[0040] As Figure 4 shown, considering the transportability of the unmanned aerial vehicle, in the ground parking state, the lift rotor 10 can rotate around the lower fixed hinge 14 to a direction parallel to the symmetry plane of the unmanned aerial vehicle, and the arm 30 can rotate around the folding hinge 32 to a retracted state, so that the present invention meets the size requirements for container transportation.

[0041] As Figure 5As shown, the present invention adopts a series-parallel hybrid power system architecture. The engine and the motor jointly provide power. A part of the power of the engine directly drives the lift rotor, and the remaining power supplies the battery pack and the motor through the generator, so as to drive the attitude rotor and other electrical devices on the aircraft. During the operation of the present invention, the battery pack first provides starting power for the engine, and the energy management system distributes a reasonable energy flow according to the state of charge of the battery pack and the required power on the propeller shaft to provide the power required for the stable flight of the UAV: at low load, the power of the engine is redundant, and the attitude rotor is mainly driven by the generator, and the redundant power is used to charge the battery pack; at high load, the engine first ensures the operation of the lift rotor, the output power of the generator is low, and the attitude rotor is jointly driven by the generator and the battery pack. During the flight, the energy management system ensures that the engine always operates stably at the best working condition.

[0042] Combined with Figure 6 , the fault reconstruction scheme of the present invention will be described in detail.

[0043] When a fault occurs in the lift rotor, such as the upper lift rotor has no power output due to blade damage, the flight control system detects a height drop and torque imbalance, and takes the following isolation and control measures: (1) Lift rotor power adjustment: After detecting the fault of the upper lift rotor, immediately reduce the output of the lower lift rotor through the flight control system to reduce the reverse torque and avoid excessive torque imbalance at the same time; (2) Attitude rotor power compensation: Since part of the lift rotor fails, it is necessary to compensate for the lift, and the body generates an unbalanced moment. Adjust the output of the attitude rotor to balance the moment. The power of the front left and rear left attitude rotors is increased significantly, and the power of the front right and rear right attitude rotors is increased slightly; (3) Adjust the overall control strategy: The flight control system monitors the attitude angle and speed of the aircraft in real time through the automatic flight control system, gradually adjusts the power of the attitude rotor, the flight control system switches to the alternate landing safe flight mode, and guides the aircraft to quickly land in a safe area. Evaluating the feasibility of the fault exclusion measures, the present invention can quickly enter the state of stable hovering or safe landing in case of failure, without out-of-control or severe vibration.

[0044] When the attitude rotor malfunctions, such as the front left attitude rotor motor being damaged and the flight control system detects the failure of the front left rotor output, the following isolation and control measures are taken: (1) Attitude rotor power adjustment: The front right attitude rotor appropriately reduces thrust to prevent the airframe from tilting to the left. The rear right attitude rotor increases thrust to generate a counterclockwise moment to compensate for the failure of attitude rotor 1. The rear left attitude rotor reduces thrust to balance the overall attitude moment. (2) Overall attitude control: Use the remaining three attitude rotors to maintain the balance of the aircraft, reduce maneuvering actions, and the flight control system switches the flight mode to the alternate landing safety mode, gradually reducing the altitude and landing. Evaluating the feasibility of the troubleshooting measures, the present invention can maintain the basic stability of the flight attitude without deviating from the control target in the case of a failure of one attitude rotor, and the flight control system can successfully guide the UAV to land safely.

[0045] When all battery SOCs are too low, such as battery aging or capacitor failure caused by extreme temperature, and the battery management system detects that the battery power rapidly drops to the critical value, the following isolation and control measures are taken: (1) Power supply switching: The engine directly supplies power to the attitude rotor. (2) Attitude rotor power adjustment: Reduce the response rate of the attitude rotor and reduce complex maneuvering actions. (3) Adjust the flight plan: According to the remaining fuel and the total aircraft power requirement, change the flight plan. Evaluating the feasibility of the troubleshooting measures, the present invention can quickly switch to the safe mode, with stable attitude and safe landing, and the system power supply switching is smooth without obvious fluctuations.

[0046] When the fuel is insufficient, such as when the fuel storage tank leaks, the fuel sensor detects that the fuel quantity rapidly drops and approaches the critical value, and the following isolation and control measures are taken: (1) Power supply switching: Enable the backup battery pack. (2) Energy strategy adjustment: Reduce the power of the lift rotor and give priority to ensuring the power supply of the generator. (3) Adjust the overall control strategy: Real-time monitor the attitude angle and speed of the aircraft through the automatic flight control system, gradually adjust the power of the attitude rotor, the flight control system switches to the alternate landing safety flight mode, and guides the aircraft to quickly land in a safe area. Evaluating the feasibility of the troubleshooting measures, the present invention can quickly stop flying forward, enter a stable landing procedure, and land safely without unstable attitude or out-of-control situation.

[0047] Key points of the present invention

[0048] 1. Configuration control: The lift rotor referring to the helicopter configuration provides the main lift, and the attitude rotor referring to the quadcopter UAV mainly provides the attitude control moment. The flight control mainly adopts the attitude control principle of the quadcopter UAV.

[0049] 2. Foldable arms: With the help of the rotating mechanism, the attitude rotor arms and the lift rotor can be retracted.

[0050] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can still make several modifications and improvements without departing from the principle of the present invention, and these should also be regarded as falling within the protection scope of the present invention.

Claims

1. A foldable multi-rotor hybrid unmanned transport aircraft, characterized in that, It includes a lift rotor (10), an attitude rotor (20), an arm (30), a cabin (40), an optoelectronic pod (50), a cargo hold (60) and a landing gear (70); The lift rotor (10) is a coaxial rotor and is installed at the central axis position on the upper part of the cabin (40); the lift rotor (10) includes an upper propeller (11), an upper fixed hinge (12), a lower propeller (13), a lower fixed hinge (14) and a lift rotor base (15); the upper fixed hinge (12) and the lower fixed hinge (14) are installed side by side vertically on the lift rotor base (15), the upper propeller (11) is installed on the upper fixed hinge (12), and the lower propeller (13) is installed on the lower fixed hinge (14); there is a (180)° angle between the tips of the upper and lower propellers, and the rotating shafts of the upper and lower propellers enter the cabin from the lift rotor base (15) and are connected to the reduction drive system; Four groups of attitude rotors (20) are evenly distributed around the cabin (40) in an "X" layout. The four groups of attitude rotors (20) correspond to four arms (30). The arms (30) are used to connect the attitude rotors (20) and the cabin (40). Each arm (30) includes a connecting rod (31) and a folding hinge (32); one end of the folding hinge (32) is connected to the cabin (40), and the other end is connected to the connecting rod (31); by pushing the connecting rod (31), the folding hinge (32) drives the arm (30) to rotate, realizing the deployment and folding of the arm (30); The cabin (40) is the core load-bearing structure of the whole machine, with an air inlet on the outside and airborne equipment installed inside; The optoelectronic pod (50) is installed at the lower front position of the cabin (40); the cargo hold (60) is installed at the central position at the bottom of the cabin (40); the landing gear (70) is fixed to the bottom of the cabin (40) to play a supporting and buffering role.

2. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 1, characterized in that The folding hinge (32) consists of a rotating hinge fixed on the cabin (40) and an eccentric locking pin. An angle limiter is arranged inside the rotating hinge, which can realize the positioning and stopping of two states of (0)° and (45)°. The eccentric locking pin assembly is arranged outside the rotating hinge to realize the locking of the arm (30) in the deployed and folded states.

3. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 1, wherein The number of the landing gears (70) is (2), and they are fixed to the bottom of the cabin (40) in a symmetric arrangement.

4. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 3, wherein The landing gear (70) is fixed to the cabin (40) by welding.

5. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 1, characterized in that Each group of attitude rotors (20) is provided with an independent motor.

6. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 1, characterized in that, It also includes a series-parallel hybrid power device. The series-parallel hybrid power device includes an energy management system, an engine, a battery pack and a motor. The energy management system is used to distribute the power of the engine. A part of the power of the engine directly drives the lift rotor, and the remaining power supplies power to the battery pack and the motor through a generator.

7. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 6, wherein, During operation, the battery pack first provides starting power for the engine, and the energy management system distributes the energy flow according to the state of charge of the battery pack and the power required on the propeller shaft.

8. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 7, wherein, Under low load, the power of the engine is redundant. The attitude rotor is mainly driven by the generator, and the redundant power is used to charge the battery pack; under high load, the engine first ensures the operation of the lift rotor, the output power of the generator is low, and the attitude rotor is driven by the generator and the battery pack together.

9. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 1, wherein, When the upper propeller (11) fails, the output of the lower propeller (13) decreases to reduce the reverse torque, and at the same time the attitude rotor power increases.

10. The foldable multi-rotor hybrid unmanned transport aircraft according to claim 1, wherein, The internal airborne equipment includes a flight control equipment box (42), a fuel storage tank (43), a lubricating oil and cooling system (44), an aviation piston engine (45), a reduction and transmission system (46), a generator (47), a battery pack (48), and an exhaust port (49). Each of the above components is symmetrically arranged along the longitudinal middle section of the cabin.

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