Rapid sea-air cross-domain amphibious unmanned aerial vehicle

Abstract

The invention discloses a rapid sea-air cross-domain amphibious unmanned aerial vehicle, and belongs to the field of cross-domain unmanned platforms. The system is composed of a control system, a sensing system, an energy storage system, an attitude control system and a rapid cross-domain system. The control system, the sensing system and the energy storage system are integrated in a watertight compartment in the middle of the unmanned aerial vehicle, the control system is located in the middle of the watertight compartment, the sensing system is located at the top of the watertight compartment, and the energy storage system is located at the bottom of the watertight compartment. The attitude control systems are radially distributed around the unmanned aerial vehicle, and the rapid cross-domain system is distributed on the periphery of a watertight compartment in the middle of the unmanned aerial vehicle. The attitude control system comprises rotor wings, rotor wing motors, rotor wing arms and variable-structure steering engines which are distributed on the periphery of the unmanned aerial vehicle in a radial mode. The energy storage system comprises a battery pack and a protection plate. According to the method, directional fast domain crossing can be realized, and the domain crossing speed and stability are improved. The unmanned aerial vehicle further has the advantages of being good in waterproofness, good in underwater posture adjusting performance, high in flexibility, high in cruising ability, small in size, light in weight, simple in structure, high in flexibility and the like.

Description

Technical Field

[0001] The present invention relates to a fast sea-air cross-domain amphibious unmanned aerial vehicle, belonging to the field of cross-domain unmanned platforms. Background Art

[0002] With the development of military confrontation technologies and means, the capabilities of single-medium space vehicles in multi-dimensional situation awareness, information interaction, penetration attack, etc. are restricted.

[0003] A sea-air amphibious unmanned aerial vehicle is a device that can navigate across domains in air and water. The sea-air amphibious unmanned aerial vehicle was initially envisioned for use in military combat, and later, with the development of concepts and technologies, it has been more widely applied in civilian fields, such as deep-sea salvage and maritime rescue. Traditional devices such as helicopters, ships, and submarines often have a fixed range of motion in a single-medium space, and the human, material, and time costs required for operation are relatively high, and there are also many issues that need to be considered. The sea-air amphibious unmanned aerial vehicle can reach the predetermined sea area quickly in flight state to conduct autonomous target detection, evaluate the quality of the surrounding sea area environment, and then cross to underwater for close observation, giving full play to its advantages of speed and flexibility.

[0004] Existing mature sea-air amphibious unmanned aerial vehicles often adopt a multi-rotor configuration, with several rotors arranged around the main body. By using the reaction force received when the rotors rotate in air or water, the unmanned aerial vehicle is propelled to move, having good flexibility and reliability.

[0005] The patented water-air robot (CN110979666A) proposed an eight-rotor sea-air unmanned aerial vehicle. The unmanned aerial vehicle consists of a central main body and four water-air dual-purpose propulsion devices radially distributed around it. Each propulsion device is equipped with one water rotor and one air rotor, and the directions of the rotors are fixed. The unmanned aerial vehicle uses the corresponding rotors in different media to achieve water-air amphibious drive, and at the same time, attitude adjustment is achieved by controlling the rotation speeds of the rotors.

[0006] The patented water-air amphibious unmanned aerial vehicle (CN117885924A) proposed a new type of small four-rotor unmanned aerial vehicle. The unmanned aerial vehicle consists of a central main body and four two-speed propulsion devices radially distributed around it. The propulsion device has a variable speed mechanism, which can switch the speed and torque range in different media, provide sufficient thrust and ensure output efficiency. The propulsion device is connected to the main body through a rotatable mounting arm, and a servo motor drives the mounting arm to rotate to achieve rotor thrust vectorization, enhancing underwater maneuverability.

[0007] The patent "A Submersible Hydro-Aerial Unmanned Aerial Vehicle" (CN114537661A) proposes an eight-rotor hydro-aerial unmanned aerial vehicle that can fly at low speeds in water and high speeds in the air. The unmanned aerial vehicle consists of a central main body and eight propulsion devices radially distributed around it. The propulsion devices can change the shape of the mounting arm through a servo motor to control the rotor direction, thereby realizing the vectorization of the rotor thrust and enhancing the attitude control ability.

[0008] The patent "A Quadrotor Amphibious Unmanned Aerial Vehicle for Emergency Monitoring of Seawater Profile Environment" (CN117584677A) proposes a quadrotor sea-air unmanned aerial vehicle with a floating device. The unmanned aerial vehicle consists of a central sealed cabin, a floating device, and four rotors radially distributed around it. The four rotors provide the main power, and the floating device adjusts the buoyancy by filling and discharging water to achieve submergence depth control. Summary of the Invention

[0009] The object of the present invention is to provide a fast sea-air cross-domain amphibious unmanned aerial vehicle to achieve directional and fast cross-domain, and improve the speed and stability of cross-domain. The present invention also has the advantages of good waterproof performance, good underwater attitude adjustment performance, high flexibility, strong endurance, small volume, light weight, simple structure, and high flexibility.

[0010] The object of the present invention is achieved through the following technical solutions:

[0011] A fast sea-air cross-domain amphibious unmanned aerial vehicle disclosed by the present invention consists of a control system, a sensing system, an energy storage system, an attitude control system, and a fast cross-domain system. Among them, the control system, the sensing system, and the energy storage system are integrated in a watertight cabin in the middle of the unmanned aerial vehicle. The control system is located in the middle of the watertight cabin, the sensing system is located at the top of the watertight cabin, and the energy storage system is located at the bottom of the watertight cabin. Among them, the attitude control system is radially distributed around the unmanned aerial vehicle, and the fast cross-domain system is distributed around the watertight cabin in the middle of the unmanned aerial vehicle.

[0012] Among them, the control system includes a controller and a wireless communication module, which are integrated in the middle of the watertight cabin in the middle of the unmanned aerial vehicle.

[0013] The controller is a control board that receives information from various sensors and communicators, judges the environment and working conditions, and serves as a slave computer to conduct overall control of each system of the whole machine.

[0014] The wireless communication module is an expansion module of the above controller, communicates with the master computer through electromagnetic waves, and transmits instructions to ensure the controllability of the unmanned platform.

[0015] Among them, the sensing system includes a camera, a millimeter-wave radar, and an inertial control unit, which are integrated at the top of the watertight cabin in the middle of the unmanned aerial vehicle.

[0016] The camera is used to obtain visual information around the unmanned platform, and the millimeter-wave radar can obtain radar information around the unmanned platform. The camera cooperates with the millimeter-wave radar to assist the control system in SLAM mapping.

[0017] The inertial control unit can detect the attitude and position information of the unmanned platform in real time, and assist the control system in positioning and attitude control of the unmanned aerial vehicle.

[0018] The energy storage system includes a battery pack and a protection board, which are integrated at the bottom of the watertight compartment in the middle of the drone.

[0019] The battery pack is a combination of multiple lithium batteries, which is sealed by a waterproof shell and a sealing strip, has good waterproof measures, and provides power for the whole machine.

[0020] The protection board balances the voltage of each battery to ensure the safety of the battery during operation.

[0021] The attitude control system includes rotors, rotor motors, rotor arms, and variable-speed servos, which are radially distributed around the drone.

[0022] The rotor is a dual-purpose rotor for water and air, based on an optimized dual-purpose blade shape, which balances the performance of adapting to the air environment and the underwater environment, and is driven by a rotor motor to provide rotor thrust for the entire machine.

[0023] The rotor motor is a high-speed UAV power motor, located at the end of the rotor arm away from the watertight compartment, with its stator fixed to the arm body, the rotor fixed to the rotor, and the rotating shaft perpendicular to the arm axis, so that the rotor arm can change the direction of the rotor by rotating around the axis. The rotor motor enables the UAV to fly at a speed of no less than 15m / s in the air and no less than 3m / s underwater.

[0024] The rotor arm is made of carbon fiber lightweight material.

[0025] The allosteric servo is a high-power and high-torque self-locking servo that can perform precise position closed-loop control. It is located at one end of the rotor arm near the middle watertight compartment. The stator is fixedly connected to the watertight compartment, the rotor is fixedly connected to the arm body, and the rotating shaft coincides with the arm shaft. This servo can drive the rotor arm to rotate around the axis, thereby changing the rotor orientation and realizing the vectorization of the rotor thrust. Through rotor allosterism and speed control, the UAV has multiple navigation modes: in the standard navigation mode, the orientations of all rotors are the same, either upward or downward. The principle of this mode is similar to that of ordinary multi-rotor UAVs, and it can not only achieve flight in the air but also underwater navigation. With the ballast tank, the standard navigation mode can also achieve underwater tilt adjustment; in the horizontal propulsion navigation mode, two non-adjacent rotors interrupt power, and the other two rotors have the same orientation, both horizontal. With the ballast tank, this mode can achieve underwater horizontal navigation; in the autorotation navigation mode, the orientations of all rotors are horizontal, and the directions of the torques generated by the thrusts of all rotors relative to the central axis of the UAV are the same. With the ballast tank, this mode can achieve underwater rotation around the axis. Through the coordination of each navigation mode and the cooperation of the ballast tank, the UAV can achieve delicate horizontal navigation, autorotation, and tilt attitude adjustment.

[0026] Among them, the rapid cross-domain system includes ballast tanks and nozzles, which are distributed around the watertight compartment in the middle of the UAV.

[0027] The ballast tank is a high-pressure water tank that can be independently filled and drained and actively pressurized. The water volume and water pressure are controlled by their respective valves and pumps, and are connected to the nozzles through pipelines. If all water tanks are filled and drained simultaneously, the diving depth of the UAV can be controlled. If some water tanks are filled and drained, the inclination angle of the UAV can be slightly controlled. When the UAV performs water-air cross-domain takeoff, all water tanks are pressurized simultaneously, and the nozzles are opened at the same time. The water in the water tanks is ejected at high speed, enabling the UAV to obtain an upward impulse and quickly complete the cross-domain process, ensuring that the cross-domain takeoff time of the UAV is not higher than 10 s.

[0028] The method of attitude control by regulating the water storage volume of each ballast tank in the rapid cross-domain system is as follows:

[0029] Taking the center of gravity of the UAV as the origin, a three-dimensional coordinate system is established. Define the direction along the axis of the UAV upward, that is, the opposite direction of the water jet direction of the nozzle, as the main motion direction, and thus define the pitch angle θ, yaw angle ψ, and spin angle where the spin angle is 0.

[0030] Number the four high-pressure water tanks as a, b, c, and d, and arrange them around the center of gravity of the UAV. The distance from the center of the structure of each high-pressure water tank to the center of gravity is l. The initial positions of the centers of the structures of water tanks a, b, c, and d are (l, 0, 0), (0, l, 0), (-l, 0, 0), and (0, -l, 0) respectively. The effective height of each high-pressure water tank is L, the effective cross-sectional area is A, and the ratio of the water filling volume to the total volume, that is, the water filling rate, is σ a , σ b , σ c , σ d .

[0031] To enable the UAV to maintain a certain diving depth without continuously floating or diving, the total buoyancy of each water tank needs to balance the gravity of the UAV, that is, the water filling rate of each water tank needs to satisfy:

[0032] σ a + σ b + σ c + σ d = C1 (1)

[0033] where C1 is a constant, and its value is related to the total weight of the UAV.

[0034] Under the condition of satisfying Equation (1), changing the water filling rate of each water tank can change the attitude of the UAV.

[0035] The buoyancy direction of each water tank is vertically upward, and the buoyancy magnitude Fi satisfies:

[0036] F i = ρ 水 gLA(1 - σ i ) (i = a, b, c, d) (2)

[0037] where ρ 水 is the seawater density and g is the acceleration due to gravity.

[0038] The coordinates of the buoyancy action point of each water tank in the UAV coordinate system are:

[0039]

[0040] Use the Euler transformation matrix to transform the above coordinates into the world coordinate system:

[0041]

[0042] The moment of the buoyancy of each water tank about the center of gravity of the UAV is:

[0043]

[0044] Solve to get:

[0045]

[0046] To enable the unmanned aerial vehicle (UAV) to maintain a certain attitude without continuous rolling, the buoyancy of non-adjacent water tanks needs to satisfy the balance relationship, that is, the water filling rate of each water tank needs to satisfy:

[0047] M a = M c (5)

[0048] M b = M d (6)

[0049] Given θ and ψ, both equations (5) and (6) are four-variable equations, and the number of equations is less than the number of unknowns. To obtain a definite solution, two supplementary equations are given based on equation (1):

[0050]

[0051] σ b + σ d = 1 (8)

[0052] By combining equations (5), (6), (7), and (8), a system of four-variable and fourth-degree equations is obtained, where the domains of σ a 、σ b 、σ c 、σ d are all in the range of [0, 1]. This system of equations has definite real solutions in the range of [0, 1].

[0053] Therefore, given the target pitch angle θ and yaw angle ψ, the attitude control can be achieved by controlling the water filling rates σ a 、σ b 、σ c 、σ d of each water tank.

[0054] After the attitude control is completed, all water tanks are pressurized simultaneously, and the nozzles are opened simultaneously, enabling the UAV to achieve directional and rapid cross-domain flight.

[0055] Beneficial effects:

[0056] 1. A fast sea-air cross-domain amphibious UAV disclosed by the present invention adopts lightweight materials and an integrated design, featuring small size, light weight, simple structure, and high flexibility. Waterproof measures such as a waterproof shell, sealing strips, and sealing rings are adopted, with good waterproof performance. It is equipped with a water-air dual-purpose propeller, having both the ability of fast underwater navigation and high-speed flight in the air.

[0057] 2. A fast sea-air cross-domain amphibious UAV disclosed by the present invention adjusts its pitch angle and yaw angle by controlling the water filling rate of each water tank, thereby realizing corresponding attitude control, having good underwater attitude adjustment performance, high flexibility, and strong endurance.

[0058] 3. A fast sea-air cross-domain amphibious UAV disclosed by the present invention, on the basis of beneficial effect 2, constructs a fast sea-air cross-domain attitude control method, and realizes accurate and efficient attitude control of the amphibious unmanned platform by quantitatively and precisely regulating the water storage capacity of each ballast water tank in the fast cross-domain system.

[0059] 4. A fast sea-air cross-domain amphibious UAV disclosed by the present invention, based on a fast water-air cross-domain mechanism that synergizes pressure injection and buoyancy control, first controls the water filling rate of the water tank to complete the attitude control required for directional cross-domain, then increases the water tank pressure and makes it spray water, and uses the impulse obtained from the water spray for cross-domain takeoff, realizing directional fast cross-domain and improving the speed and stability of cross-domain. Description of the Drawings

[0060] Figure 1 Water-air robot (CN110979666A);

[0061] Figure 2 An amphibious UAV (CN117885924A);

[0062] Figure 3 A submersible water-air UAV (CN114537661A);

[0063] Figure 4 A quadrotor amphibious UAV for emergency monitoring of seawater profile environment (CN117584677A);

[0064] Figure 5 The overall structure of a fast sea-air cross-domain amphibious UAV;

[0065] Among them: 1 - control system, 2 - sensing system, 3 - energy storage system, 4 - attitude control system, 5 - fast cross-domain system.

[0066] Figure 6 The structure of the control system;

[0067] Among them: 1.1 - controller, 1.2 - wireless communication module.

[0068] Figure 7 The structure of the sensing system;

[0069] Among them: 2.1 - camera, 2.2 - millimeter-wave radar, 2.3 - inertial control unit.

[0070] Figure 8 The structure of the energy storage system;

[0071] Wherein: 3.1 - battery pack, 3.2 - protection board.

[0072] Figure 9 Attitude control system structure;

[0073] Wherein: 4.1 - rotor, 4.2 - rotor motor, 4.3 - rotor arm, 4.4 - allosteric servo.

[0074] Figure 10 Fast cross - domain system structure;

[0075] Wherein: 5.1 - ballast tank, 5.2 - nozzle.

[0076] Figure 11 Three - dimensional coordinate system;

[0077] Wherein: a - first water tank, b - second water tank, c - third water tank, d - fourth water tank.

[0078] Figure 12 Underwater attitude adjustment mode of the sea - air amphibious UAV;

[0079] Figure 13 Fast cross - domain of the sea - air amphibious UAV. Specific implementation manner

[0080] To better illustrate the purpose and advantages of the present invention, the following further describes the content of the invention with reference to the drawings and examples.

[0081] Example 1:

[0082] As Figure 5 shown, a fast sea - air cross - domain amphibious UAV disclosed in this embodiment is characterized in that it is composed of a control system 1, a sensing system 2, an energy storage system 3, an attitude control system 4 and a fast cross - domain system 5. Among them, the control system 1, the sensing system 2 and the energy storage system 3 are integrated in the watertight cabin in the middle of the UAV. The control system 1 is located in the middle of the watertight cabin, the sensing system 2 is located at the top of the watertight cabin, and the energy storage system 3 is located at the bottom of the watertight cabin. Among them, the attitude control system 4 is radially distributed around the UAV, and the fast cross - domain system 5 is distributed outside the watertight cabin in the middle of the UAV.

[0083] Among them, the control system 1 includes a controller 1.1 and a wireless communication module 1.2, and is integrated in the middle of the watertight cabin in the middle of the UAV.

[0084] The controller 1.1 is a control board, which receives information from various sensors and communicators, judges the environment and working conditions, and serves as a lower computer to overall control each system of the whole machine.

[0085] The wireless communication module 1.2 is an expansion module of the above-mentioned controller, which communicates with the host computer through electromagnetic waves, transmits instructions, and ensures the controllability of the unmanned platform.

[0086] The perception system 2 includes a camera 2.1, a millimeter wave radar 2.2, an inertial control unit 2.3, and is integrated on the top of a watertight compartment in the middle of the UAV.

[0087] The camera 2.1 is used to obtain visual information around the unmanned platform, and the millimeter-wave radar 2.2 can obtain radar information around the unmanned platform. The camera 2.1 cooperates with the millimeter-wave radar 2.2 to assist the control system 1 in SLAM mapping.

[0088] The inertial control unit 2.3 can detect the attitude and position information of the unmanned platform in real time, and assist the control system 1 in positioning and attitude control of the unmanned aerial vehicle.

[0089] The energy storage system 3 includes a battery pack 3.1 and a protection plate 3.2, which are integrated at the bottom of the watertight compartment in the middle of the drone.

[0090] The battery pack 3.1 is a combination of multiple lithium batteries, which is sealed with a waterproof shell and a sealing strip, has good waterproof measures, and provides power for the entire machine.

[0091] The protection board 3.2 balances the voltage of each battery to ensure the safety of the battery during operation.

[0092] The attitude control system 4 includes a rotor 4.1, a rotor motor 4.2, a rotor arm 4.3, and a variable-speed servo 4.4, which are radially distributed around the UAV.

[0093] The rotor 4.1 is a dual-purpose rotor for water and air, based on an optimized dual-purpose blade shape for water and air, and takes into account both the performance of adapting to the air environment and the performance of adapting to the underwater environment. It is driven by a rotor motor 4.2 to provide rotor thrust for the entire machine.

[0094] The rotor motor 4.2 is a high-speed UAV power motor, located at the end of the rotor arm 4.3 away from the watertight compartment, with its stator fixedly connected to the arm body, the rotor fixedly connected to the rotor 4.1, and the rotating shaft perpendicular to the arm axis, so that the rotor arm 4.3 can change the direction of the rotor 4.1 by rotating around the axis. The rotor motor 4.2 enables the UAV to fly at a speed of not less than 15m / s in the air and sail at a speed of not less than 3m / s underwater.

[0095] The rotor arm 4.3 is made of carbon fiber lightweight material.

[0096] The allosteric servo 4.4 is a high-power and high-torque self-locking servo that can perform precise position closed-loop control. It is located at one end of the rotor arm 4.3 near the middle watertight cabin. The stator is fixedly connected to the watertight cabin, the rotor is fixedly connected to the arm body, and the rotating shaft coincides with the arm shaft. This servo can drive the rotor arm 4.3 to rotate around the axis, thereby changing the orientation of the rotor 4.1 and realizing the vectorization of the rotor thrust. Through rotor allosterism and speed control, the UAV has multiple navigation modes: In the standard navigation mode, the orientations of all rotors are the same, either upward or downward. The principle of this mode is similar to that of ordinary multi-rotor UAVs, and it can not only achieve flight in the air but also underwater navigation. With the cooperation of the ballast tank, the standard navigation mode can also achieve underwater inclination adjustment; In the horizontal propulsion navigation mode, the power of two non-adjacent rotors is interrupted, and the orientations of the other two rotors are the same, both horizontal. With the cooperation of the ballast tank, this mode can achieve underwater horizontal navigation; In the autorotation navigation mode, the orientations of all rotors are horizontal, and the directions of the torques generated by the thrusts of all rotors relative to the central axis of the UAV are the same. With the cooperation of the ballast tank, this mode can achieve underwater autorotation around the axis. Through the coordination of each navigation mode and the cooperation of the ballast tank, the UAV can achieve delicate horizontal navigation, autorotation, and tilt attitude adjustment.

[0097] The rapid cross-domain system 5 includes a ballast tank 5.1 and nozzles 5.2, which are distributed around the watertight cabin in the middle of the UAV.

[0098] The ballast tank 5.1 is a high-pressure water tank that can be independently filled and drained with water and actively pressurized. The water volume and water pressure are controlled by their respective valves and pumps, and it is connected to the nozzles 5.2 through pipelines. If all water tanks are filled and drained simultaneously, the diving depth of the UAV can be controlled. If some water tanks are filled and drained, the inclination angle of the UAV can be slightly controlled. When the UAV performs water-air cross-domain takeoff, all water tanks are pressurized simultaneously, and the nozzles 5.2 are opened at the same time. The water in the water tanks is ejected at high speed, enabling the UAV to obtain an upward impulse and quickly complete the cross-domain process, ensuring that the cross-domain takeoff time of the UAV is no more than 10 s.

[0099] Embodiment 2:

[0100] A rapid sea-air cross-domain amphibious UAV disclosed in this embodiment can adjust its pitch angle and yaw angle by controlling the water filling rate of each water tank, thereby realizing the corresponding attitude control.

[0101] Known: The distance from the center of the structure of each water tank to the center of gravity is l = 0.1 m, the effective height of each high-pressure water tank is L = 0.2 m, and the effective cross-sectional area is A = 0.0012 m 2 , the constant C1 = 2, the density of seawater is ρ 水 = 1000 kg / m 3 , and the acceleration due to gravity is g = 9.8 m / s 2

[0102] Attitude control objective: By controlling the water filling rate σ of each water tank a -σ d , achieve a pitch angle θ = 30° and yaw angle ψ = 30° of the UAV and the spin angle

[0103] The method of attitude control by regulating the water storage volume of each ballast tank in the fast cross-domain system is as follows:

[0104] To enable the UAV to maintain a certain diving depth without continuously floating or diving, the total buoyancy of each water tank needs to balance the gravity of the UAV, that is, the water filling rate of each water tank needs to satisfy:

[0105] σ a +σ b +σ c +σ d = C1 = 2 (1)

[0106] The buoyancy direction of each water tank is vertically upward, and the buoyancy magnitude Fi satisfies:

[0107] F i = ρ 水 gLA(1 - σ i ) (i = a, b, c, d) (2)

[0108] The coordinates of the buoyancy action point of each water tank in the UAV coordinate system are:

[0109]

[0110] Use the Euler transformation matrix to transform the above coordinates into the world coordinate system:

[0111]

[0112] The moment of the buoyancy of each water tank about the UAV's center of gravity is:

[0113]

[0114] Solve to get:

[0115]

[0116] To enable the UAV to maintain a certain attitude without continuous rolling, the buoyancy of non-adjacent water tanks needs to satisfy the balance relationship, that is, the water filling rate of each water tank needs to satisfy:

[0117] M a = M c (5)

[0118] M b = M d (6)

[0119] Based on equation (1), two supplementary equations are given:

[0120]

[0121] Combining equations (5)-(8), we get a set of four-variable quartic equations:

[0122]

[0123] The solution is:

[0124]

[0125] Therefore, by controlling the water filling rate σ of each water tank a =0.5,σ b =0.366,σ c =0.5,σ d = 0.634, which can achieve a pitch angle of θ = 30°, a yaw angle of ψ = 30° and a rotation angle of posture control.

[0126] Embodiment 3:

[0127] The present embodiment discloses a rapid water-to-air cross-domain mechanism based on the coordination of pressure injection and buoyancy control, which realizes the directional rapid cross-domain of the UAV through the coordinated control of pressure injection and buoyancy attitude adjustment, thereby improving the cross-domain speed and stability of the sea-to-air amphibious UAV.

[0128] Directional fast cross-domain goal: Achieve the UAV with a pitch angle θ = 30°, a yaw angle ψ = 30° and a rotation angle The attitude is along the main movement direction, and a cross-domain take-off is performed, and the cross-domain take-off time is no more than 10s.

[0129] Embodiment 1 discloses an amphibious drone capable of both sea and air operations, which is composed of a control system, a perception system, an energy storage system, a posture control system and a rapid cross-domain system.

[0130] The rapid cross-domain system includes ballast tanks and nozzles, which are distributed around the watertight compartment in the middle of the drone.

[0131] The ballast water tank is a high-pressure water tank that can be independently filled and discharged and actively pressurized. The water volume and water pressure are controlled by respective valves and pumps, and the tank is connected to the nozzle through a pipeline.

[0132] After completing underwater attitude control near the water surface using a method similar to Example 2, each water tank is pressurized at the same time, and the nozzle is opened at the same time, and the water in the water tank is sprayed out at high speed, so that the UAV obtains a large impulse along the main motion direction, quickly completes the directional cross-domain process, and ensures that the UAV achieves the directional rapid cross-domain goal.

[0133] The specific description above further elaborates on the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A fast sea-air cross-domain amphibious UAV, characterized in that: The system is composed of a control system (1), a perception system (2), an energy storage system (3), an attitude control system (4) and a rapid cross-domain system (5); wherein the control system (1), the perception system (2) and the energy storage system (3) are integrated in a watertight compartment in the middle of the UAV, the control system (1) is located in the middle of the watertight compartment, the perception system (2) is located at the top of the watertight compartment, and the energy storage system (3) is located at the bottom of the watertight compartment; wherein the attitude control system (4) is radially distributed around the UAV, and the rapid cross-domain system (5) is distributed outside the watertight compartment in the middle of the UAV.

2. The rapid sea-air cross-domain amphibious UAV according to claim 1, characterized in that: The control system (1) comprises a controller (1.1) and a wireless communication module (1.2), which are integrated in the middle of a watertight compartment in the middle of the UAV; The controller (1.1) is a control panel that receives information from various sensors and communicators, makes judgments about the environment and working conditions, and acts as a lower computer to perform overall control over the various systems of the entire machine; The wireless communication module (1.2) is an expansion module of the above-mentioned controller, which communicates with the host computer through electromagnetic waves to transmit instructions and ensure the controllability of the unmanned platform.

3. The rapid sea-air cross-domain amphibious UAV according to claim 1, characterized in that: The perception system (2) includes a camera (2.1), a millimeter wave radar (2.2), an inertial control unit (2.3), and is integrated on the top of a watertight compartment in the middle of the UAV; The camera (2.1) is used to obtain visual information around the unmanned platform, and the millimeter wave radar (2.2) can obtain radar information around the unmanned platform. The camera (2.1) cooperates with the millimeter wave radar (2.2) to assist the control system (1) in performing SLAM mapping; The inertial control unit (2.3) can detect the attitude and position information of the unmanned platform in real time, and assist the control system (1) in positioning and attitude control of the unmanned aerial vehicle.

4. The rapid sea-air cross-domain amphibious unmanned aerial vehicle according to claim 1, characterized in that: The energy storage system (3) includes a battery pack (3.1) and a protection plate (3.2), which are integrated at the bottom of a watertight compartment in the middle of the drone; The battery pack (3.1) is a combination of multiple lithium batteries, which is sealed by a waterproof shell and a sealing strip; The protection board (3.2) balances the voltage of each battery to ensure the safety of the battery during operation.

5. The rapid sea-air cross-domain amphibious UAV according to claim 1, characterized in that: The attitude control system (4) includes a rotor (4.1), a rotor motor (4.2), a rotor arm (4.3), and a variable-speed steering gear (4.4), which are radially distributed around the UAV; The rotor (4.1) is a dual-purpose rotor for water and air, based on an optimized dual-purpose blade shape for water and air, and balances the performance of adapting to the air environment and the underwater environment. It is driven by a rotor motor (4.2) to provide rotor thrust for the whole machine; The rotor motor (4.2) is a high-speed UAV power motor, located at the end of the rotor arm (4.3) away from the watertight compartment, with its stator fixedly connected to the arm body, the rotor fixedly connected to the rotor (4.1), and the rotating shaft perpendicular to the arm axis, so that the rotor arm (4.3) can change the direction of the rotor (4.1) by rotating around the axis; the rotor motor (4.2) enables the UAV to fly at a speed of not less than 15 m / s in the air and sail at a speed of not less than 3 m / s underwater; The rotor arm (4.3) is made of carbon fiber lightweight material; The allosteric servo (4.4) is a high-power and high-torque self-locking servo that can perform precise position closed-loop control. It is located at one end of the rotor arm (4.3) close to the middle watertight cabin. The stator is fixedly connected to the watertight cabin, the rotor is fixedly connected to the arm body, and the rotating shaft coincides with the arm shaft. This servo can drive the rotor arm (4.3) to rotate around the axis, thereby changing the orientation of the rotor (4.1) and realizing the vectorization of the rotor thrust. Through rotor allosterism and speed control, the UAV has multiple navigation modes: In the standard navigation mode, the orientations of all rotors are the same, either upward or downward. The principle of this mode is similar to that of a common multi-rotor UAV, and it can not only achieve flight in the air but also underwater navigation. With the cooperation of the ballast tank, the standard navigation mode can also achieve underwater inclination adjustment. In the horizontal propulsion navigation mode, the power of two non-adjacent rotors is interrupted, and the orientations of the other two rotors are the same, both horizontal. With the cooperation of the ballast tank, this mode can achieve underwater horizontal navigation. In the autorotation navigation mode, the orientations of all rotors are horizontal, and the directions of the torques generated by the thrusts of all rotors relative to the central axis of the UAV are the same. With the cooperation of the ballast tank, this mode can achieve underwater autorotation around the axis. Through the coordination of each navigation mode and the cooperation of the ballast tank, the UAV can achieve delicate horizontal navigation, autorotation, and tilt attitude adjustment.

6. The rapid sea-air cross-domain amphibious UAV according to claim 1, characterized in that: The rapid cross-domain system (5) includes a ballast tank (5.1) and nozzles (5.2), which are distributed around the watertight cabin in the middle of the UAV. The ballast tank (5.1) is a high-pressure water tank that can be independently filled and drained with water and actively pressurized. The water volume and water pressure are controlled by their respective valves and pumps and are connected to the nozzles (5.2) through pipelines. If all water tanks are filled and drained simultaneously, the diving depth of the UAV can be controlled. If some water tanks are filled and drained, the inclination of the UAV can be slightly controlled. When the UAV performs water-air cross-domain takeoff, all water tanks are pressurized simultaneously, and the nozzles (5.2) are opened at the same time. The water in the water tanks is ejected at high speed, enabling the UAV to obtain an upward impulse and quickly complete the cross-domain process, ensuring that the cross-domain takeoff time of the UAV is no more than 10 s. By regulating the water storage capacity of each ballast tank in the rapid cross-domain system (5).

7. The rapid sea-air cross-domain amphibious unmanned aerial vehicle according to claim 6, characterized in that: The method of attitude control by regulating the water storage capacity of each ballast tank in the rapid cross-domain system (5) is as follows. Taking the center of gravity of the drone as the origin, a three-dimensional coordinate system is established; the direction along the axis of the drone upward, that is, the opposite direction of the water spraying direction of the nozzle, is defined as the main motion direction, thereby defining the pitch angle θ, the yaw angle ψ and the rotation angle where the rotation angle is 0; Number the four high-pressure water tanks as a, b, c, and d, and arrange them around the center of gravity of the UAV respectively. The distance from the structural center of each high-pressure water tank to the center of gravity is l. The initial positions of the structural centers of water tanks a, b, c, and d are (l, 0, 0), (0, l, 0), (-l, 0, 0), and (0, -l, 0) respectively; the effective height of each high-pressure water tank is L, the effective cross-sectional area is A, and the ratio of the water filling volume to the total volume, that is, the water filling rates are σ a , σ b , σ c , σ d ; To enable the UAV to maintain a certain diving depth without continuously floating or diving, the total buoyancy of each water tank needs to balance the gravity of the UAV, that is, the water filling rate of each water tank needs to satisfy: σ a +σ b +σ c +σ d =C1 (1) where C1 is a constant, and its value is related to the total weight of the UAV. Under the condition of satisfying formula (1), changing the water filling rate of each water tank can change the attitude of the UAV. The buoyancy direction of each water tank is vertically upward, and the buoyancy magnitude Fi satisfies: F i = ρ 水 gLA(1 - σ i ) (i = a, b, c, d) (2) where ρ 水 is the seawater density and g is the acceleration due to gravity; The coordinates of the buoyancy action point of each water tank in the UAV coordinate system are: Use the Euler transformation matrix to transform the above coordinates into the world coordinate system: The moment of the buoyancy of each water tank about the center of gravity of the UAV is: Solve to get: To enable the UAV to maintain a certain attitude without continuously rolling, the buoyancies of non-adjacent water tanks need to satisfy the balance relationship, that is, the water filling rate of each water tank needs to satisfy: M a = M c (5) M b = M d (6) Given θ and ψ, both equations (5) and (6) are quartic equations, and the number of equations is less than the number of unknowns. To obtain a definite solution, two supplementary equations are given based on equation (1): σ b +σ d =1 (8) Combining equations (5), (6), (7), and (8) gives a quartic equation system of four variables, where the domains of σ a , σ b , σ c , and σ d are all [0, 1]; the equation system has definite real solutions on [0, 1]; Thus, given the target pitch angle θ and yaw angle ψ, the corresponding attitude control can be achieved by controlling the water filling rates σ a , σ b , σ c , σ d of each water tank; After attitude control is completed, each water tank is pressurized simultaneously, and the nozzle (5.2) is opened simultaneously, enabling the UAV to achieve rapid cross-domain orientation.

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