A large-load multi-rotor water-air dual-powered cross-medium UAV

Abstract

The present invention discloses a large-load multi-rotor water-air dual-power cross-medium UAV, comprising a UAV frame, on which arms are arranged in an "X" configuration and symmetrically arranged at 90 degrees, and a water-air power system is coaxially installed at the end of the arm, wherein the air power system is installed on the upper surface of the arm, and the underwater power system is kept on the same axis as the air power and installed on the lower surface of the arm. A fully enclosed waterproof compartment is installed at the center position above the frame; a water depth sensor and a range-finding sonar for measuring depth are installed on one side below the fully enclosed waterproof compartment, an external barometer is installed on the other side below the waterproof compartment, and a fully enclosed payload compartment is installed directly below the frame. Under the premise of carrying a load of no less than 10kg, the present invention assists the UAV in completing aerial fixed-altitude movement through an external barometer; through the water-air coaxial distribution of the water-air power system and the foldable arm, the UAV can achieve free navigation in the air, water-air cross-medium movement, free navigation underwater, and underwater fixed-point operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicles (UAVs), and in particular relates to a large-load multi-rotor water-air dual-power cross-medium UAV. Background Art

[0002] Existing common drones can only work in the air, underwater submersibles can only operate underwater, and common amphibious drone aircraft usually float on the water surface and do not go deep into the water. Water-air cross-medium drones combine the characteristics of aerial drones and underwater submersibles. Compared with all current unmanned aerial vehicles, they have a broad application space and use value.

[0003] Currently, research on cross-medium UAVs is quite active, but most designs focus on improving the UAV's fluid dynamics, using single-layer propulsion or buoyancy-driven methods to achieve motion control. However, these UAVs carry very small payloads, resulting in significant structural impact when entering and exiting the water. Other research focuses on multi-rotor cross-medium UAVs. Similarly, these often use buoyancy-driven methods for underwater navigation combined with fixed-wing structures, but their payloads remain very small, limiting their potential applications.

[0004] After searching, the Chinese patent application number is 202211071852.0, the application date is September 2, 2022, and the name of the invention patent is Water-Air Dual-Power Tilt-Rotor Cross-Medium UAV. This invention combines the characteristics of fixed wings and tilt-rotor multi-rotors to enhance the fluid dynamics performance of the UAV during cross-medium movement. However, it does not take into account the great difference in propellers suitable for water-air media. It only uses a set of aerial rotors to complete the UAV's air and underwater movements. The underwater maneuverability of the designed UAV is poor.

[0005] In 2021, Lu Di published a doctoral thesis titled "Research on New Multi-mode Sea and Air Amphibious Vehicles and Their Cross-Media Process Control Methods". The article introduced a number of cross-media drones developed by his team. The prototypes basically adopt a single-layer power + underwater buoyancy drive method, do not have high requirements for load capacity, and their underwater maneuverability is poor.

[0006] In summary, most of the current cross-medium UAVs have a small payload and use single-layer power or buoyancy drive, which has great limitations. Therefore, it is necessary to design a water-air dual-power cross-medium UAV with a large payload and flexible water-air maneuverability. Summary of the Invention

[0007] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a large-load multi-rotor water-air dual-power cross-medium UAV. On the premise of carrying a load of no less than 10kg, the UAV uses an external barometer to assist the UAV in completing the fixed-altitude movement in the air; through the water-air coaxial distribution water-air power system and foldable arms, the UAV can realize free navigation in the air, water-air cross-medium movement, free navigation underwater and underwater fixed-point operation.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A large-load multi-rotor water-air dual-powered cross-medium UAV includes a frame on which are symmetrically mounted arms 4, a waterproof compartment 7, a payload compartment 8, and a barometer 17; the arms 4 are in an "X" configuration, with a water-air power system mounted at the end of each arm 4, the water-air power system comprising an aerial power system and an underwater power system; the aerial power system is mounted on the upper side of the arms 4, and the underwater power system is mounted on the lower side of the arms 4 and maintained on the same axis as the aerial power system;

[0010] The two arms 4 in front of the UAV waterproof compartment are connected to the fuselage through a high-torque servo 18, which is used to achieve free rotation at a large angle and assist the arms in completing backward folding; the two arms 4 at the rear of the waterproof compartment are connected to the arm connector 19 on the fuselage through screws, and the arms 4 rotate around the arm connector 19 through screws to achieve downward vertical folding of the arms.

[0011] The waterproof compartment 7 and the load compartment 8 are both fully enclosed compartments, and the load compartment 8 is located below the waterproof compartment 7;

[0012] The barometer 17 is external and used to measure the altitude of the drone in real time and provide it to the drone flight controller. The flight controller calculates the altitude control signal through the internal altitude control algorithm and sends it to the air power system to assist the drone in completing the altitude-fixed movement in the air.

[0013] The front arm 4 of the drone arm 4 is used for the drone to carry out underwater operations close to the target; the aerial power system above the drone arm 4 is composed of four sets of brushless motors 2 and matching aerial rotors 1, and is installed close to the upper surface of the arm 4.

[0014] The aerial rotor 1 is a 27-inch two-blade propeller.

[0015] The vertical distance between the aerial power system and the underwater power system is 16 cm; the fully enclosed waterproof compartment 7 is cylindrical, and the underwater power system under the drone arm 4 is composed of four groups of underwater thrusters 3, which are kept on the same axis as the aerial power, and are used to provide the drone with a certain angle of inclination underwater and at the water-air interface, so that the drone's underwater movement and water-air interface movement are reliable and flexible.

[0016] The underwater power system includes an underwater propeller 3 and a side underwater propeller 5. A pair of underwater propellers 3 are installed on the central side below the frame, and the underwater propellers 3 are connected to the machine arm 4.

[0017] The underwater thrusters 5 are installed horizontally on both sides below the center of the frame to increase the underwater navigation speed of the UAV. At the same time, when the UAV hovers at the water-air interface and withstands the wind and waves on the water surface, the UAV's rotation around the axis is limited, thereby improving the reliability of the UAV's surface takeoff.

[0018] The fully enclosed waterproof compartment 7 of the UAV is used to install the battery 9, ESC, flight control board, cables, distribution board 11, relay, image transmission and receiver 10 and camera 14;

[0019] The battery 9 is connected to the distribution board 11 through a relay, and the distribution board 11 provides processed driving voltage to the flight control board, electronic speed controller, image transmission and receiver 10, and camera 14 through cables; the electronic speed controller provides driving voltage for aerial power and underwater power; the relay is responsible for switching the battery, and the image transmission and receiver 10 and camera 14 are responsible for providing drone remote control signals and real-time navigation image information.

[0020] The fully enclosed payload compartment 8 is used to carry a large payload of at least 10 kg, is supported by a bottom circular bracket, and is fixedly connected to the UAV frame by a bottom support plate.

[0021] The detection instrument includes a water depth sensor 15 and a ranging sonar 16. The water depth sensor 15, the ranging sonar 16 and the barometer 17 are controlled by the UAV control system. The UAV control system adopts a master-slave control mode; the main control board 12 adopts a Pixhawk flight control, which is connected to an external barometer 17 to provide altitude information for the UAV; the slave control board 13 adopts an STM32 chip, which is connected to the water depth sensor 15 and the ranging sonar 16 to provide the UAV with water-air power switching and underwater depth and altitude information.

[0022] The barometer 17 is externally arranged to measure the altitude of the drone in real time and assist the drone in completing the altitude-fixed movement in the air, thereby effectively solving the problem of the flight control board's onboard barometer failure caused by the fully enclosed waterproof chamber 7.

[0023] The drone frame is set in an "X" configuration and is installed symmetrically at 90 degrees.

[0024] The water depth sensor 15 is an external water depth sensor MS5837, which is installed outside the fully enclosed waterproof compartment 7. The ranging sonar 16 is a ranging sonar DE_WLM36. The water depth sensor 15 is installed below the water depth sensor 15 at a parallel distance of 25 cm and close to the side underwater thruster 5. The ranging sonar 16 is used to obtain the underwater height information of the drone and assist the drone in completing underwater height-fixing movement.

[0025] Beneficial effects of the present invention:

[0026] First, the present invention adopts a double-layer power system consisting of an aerial motor 1 and an underwater propeller 3 in combination with an auxiliary motor 5 to design a multi-rotor drone that can repeatedly perform water-to-air crossing movements.

[0027] Second, the fully enclosed waterproof compartment 7 and payload compartment 8 adopted in the present invention make the cross-media UAV design modular and make its waterproofing work sustainable.

[0028] Third, the present invention improves the load requirements of cross-medium UAVs. By switching and coordinating the high-thrust aerial motor and the high-thrust underwater propeller in different media, and combining the multi-rotor UAV control distribution technology, the load capacity of the multi-rotor cross-medium UAV is increased to 10kg, greatly expanding the application space of the UAV.

[0029] Fourth, the present invention places the altitude sensor of the cross-medium UAV externally, solving the problem of malfunction of the onboard altitude sensor caused by the closure of the waterproof compartment.

[0030] Fifth, the present invention integrates the data of the water depth sensor 15 and the ranging sonar 16 to simultaneously provide the cross-medium UAV with water-to-air identification signals and underwater height signals, thereby assisting the UAV in completing underwater altitude-fixed navigation.

[0031] Sixth, the present invention adopts a foldable arm 4, and the UAV can be transformed underwater, further expanding the application space of the UAV and enriching the application value of the cross-media UAV. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the aerial rotor and underwater propeller of the present invention.

[0033] Figure 2 Schematic diagram of the structure of an example of the present invention.

[0034] Figure 3 This is a schematic diagram of the fully enclosed waterproof compartment of the drone of the present invention.

[0035] Figure 4 This is a schematic diagram of the installation of the water depth sensor and ranging sonar of the present invention.

[0036] Figure 5 It is a schematic diagram of the installation of the barometer 17 of the present invention.

[0037] Figure 6 This is a schematic diagram of the folding arm of an example of the present invention.

[0038] Figure 7 This is a schematic diagram of the arm servo drive structure of an example of the present invention.

[0039] Figure 8 Schematic diagram of a control system of an example of the present invention.

[0040] Reference numerals:

[0041] 1-Aerial rotor, 2-Aerial motor, 3-Underwater thruster, 4-Arm, 5-Side underwater thruster, 6-Landing gear, 7-Fully enclosed waterproof compartment, 8-Payload compartment, 9-Battery, 10-Image transmitter and receiver, 11-Distribution board, 12-Master control board, 13-Slave control board, 14-Camera, 15-Water depth sensor, 16-Ranging sonar, 17-External barometer. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] like Figures 1-8 As shown, a large-load cross-medium UAV in an example of the present invention includes: a frame, an aerial rotor 1, an aerial motor 2, an underwater propeller 3, an arm 4, a side underwater propeller 5, a landing gear 6, a fully enclosed waterproof compartment 7, and a payload compartment 8.

[0044] like Figure 6 、 7 As shown, the drone frame is equipped with four symmetrically distributed foldable arms 4. The flight control panel uses PWM waves to drive the servos to fold the two arms 4 in front of the waterproof compartment. The two rear arms 4 can be manually folded vertically during transport or when not in use. The air-water propulsion system is mounted on a common axis perpendicular to the ends of the arms 4. To ensure the symmetry of the drone's overall structure, a fully enclosed cylindrical waterproof compartment is installed in the center of the frame. A pair of underwater thrusters 3 are also symmetrically mounted on the sides of the center of the frame. The upper arm 4 is mounted close to the surface of the arm's end. The underwater propulsion system, located below the arm 4 and coaxial with the air-water propulsion system, is set 25 cm from the lower surface of the arm 4 to provide a certain angle of tilt for the drone underwater and at the water-air interface. The air-water propulsion system, namely the brushless motor and rotor, is mounted above the arm's end, while the underwater propulsion system, namely the underwater motor and electronic speed controller, is located below.

[0045] like Figure 3As shown, the battery 9 is installed below the waterproof compartment, while the flight control board and power distribution board 11 are installed above the battery 9. The relay is used to switch the high-current battery 9 and is installed in front of the battery 9. The image transmitter and receiver 10 is installed directly below the battery 9, and the camera 14 is installed in front of the waterproof compartment to provide real-time image information.

[0046] The control system is located above the fully enclosed waterproof chamber 10 and adopts a master-slave hierarchical control method, with the master and slave controllers communicating via serial ports. The master controller 12 is equipped with an external barometer 17, and the slave controller 13 is equipped with a water depth sensor 15 and a ranging sonar 16.

[0047] A water depth sensor 15, a ranging sonar 16, and an external barometer 17 are installed around the center of the frame. The external water depth sensor 15 and ranging sonar 16 calculate the drone's underwater altitude using a slave controller's internal data fusion algorithm and transmit this information to the master controller. The master controller, using its internal altitude control algorithm, generates a real-time underwater altitude control signal, which it then sends to the slave controllers for output to the underwater propulsion system, assisting the drone in achieving altitude-fixed maneuvers underwater. The external barometer measures the drone's altitude and transmits it to the master controller. The master controller, using its internal altitude control algorithm, generates a real-time mid-air altitude control signal, which it then sends to the mid-air propulsion system, assisting the drone in achieving altitude-fixed maneuvers in mid-air.

[0048] The total thrust-to-weight ratio of the drone's aerial power system is 40kg, the maximum thrust-to-weight ratio of the underwater power system is 30kg, and the designed empty weight of the drone is 13kg. At the same time, in order to ensure that the drone's aerial power system has a safety margin of rapid response capability and avoid the drone stalling and falling due to a rapid drop in battery voltage, the final designed maximum load of the drone is 15kg, and the maximum total weight of the drone fully loaded is 28kg.

[0049] The drone payload compartment 8 can carry a maximum load of 15 kg and is supported by a bottom circular bracket and fixedly connected to the drone frame by a bottom support plate.

[0050] like Figure 1 、 2 As shown in Figures 4 and 5, the drone's aerial motor 2 cooperates with the main control board to achieve aerial navigation through the conventional four-rotor control algorithm; the underwater motor 3 and the lateral thruster 5 cooperate with the slave control board and the main control board to achieve underwater navigation of the drone; the water depth sensor 15 assists the drone in completing the water-to-air transition movement; the water depth sensor 15 and the ranging sonar 16 assist the drone in completing underwater movement.

[0051] Description of the four sports modes:

[0052] When the drone is in the air, the external barometer replaces the onboard barometer on the main control board to provide the drone with altitude information and send it to the main controller. The main controller obtains real-time altitude control signals through the internal altitude control algorithm and sends them to the air power system to assist the drone in completing altitude-fixed navigation.

[0053] When the UAV is in the water-to-air transition stage, the water depth sensor 15 on the slave controller measures the water pressure in real time and sends it to the main controller. The main controller sends a switching signal by judging whether the water pressure is greater than the designed water pressure critical value, driving the UAV's air power system and underwater power system to switch back and forth, assisting the UAV to complete the conversion of motion control modes in different media.

[0054] When the UAV is underwater, the water depth sensor 15 and the ranging sonar 16 jointly measure the underwater depth and height of the UAV, and send them to the main controller through the slave controller. The main controller obtains a real-time underwater height control signal through the data fusion algorithm and the height control algorithm, and sends it to the slave controller for output to the underwater power system to assist the UAV in completing underwater fixed-height movement.

[0055] When the UAV is in the underwater fixed-point operation mode, the arm 4 begins to fold backward while the UAV maintains the fixed-point motion mode through the internal fixed-point control algorithm, driving the UAV to closely adhere to the underwater target and start working.

[0056] like Figure 8 As shown, the high-load multi-rotor dual-powered cross-medium UAV of the present invention coordinates its two power systems through a master-slave control mode, enabling the UAV to carry a payload of up to 15kg for aerial flight, underwater navigation, multiple cross-medium maneuvers, and underwater fixed-point operations. The UAV's underwater motion control algorithm can be appropriately designed based on the layout characteristics of the underwater power system of the present invention. The UAV's cross-medium motion control algorithm can be appropriately designed based on the characteristics of the dual power system of the present invention. The UAV's underwater fixed-point operation control algorithm can be appropriately designed based on the dynamic characteristics of the UAV's folding process.

[0057] When the present invention performs fixed-point underwater operations, the arm 4 in front of the frame begins to fold backward, and the unmanned aerial vehicle configuration changes from an "X" shape to a "trapezoidal" shape. At this time, the unmanned aerial vehicle can closely adhere to the target and start operations.

[0058] The above describes specific embodiments of the present invention. Any portions not described in detail in these embodiments are commonly known in the industry and will not be described here. The present invention is not limited to the specific embodiments described above, and the above embodiments do not constitute a limitation on the scope of protection of the present invention. Any modifications or variations within the scope of the claims of the present invention fall within the scope of protection of the present invention.

Claims

1. A large-load multi-rotor water-air dual-power cross-medium UAV, characterized by: The invention comprises a frame on which an arm (4), a waterproof compartment (7), a load compartment (8) and a barometer (17) are symmetrically mounted; the arm (4) is in an "X" configuration, and a water-air power system is mounted at the end of each arm (4), and the water-air power system comprises an air power system and an underwater power system; the air power system is mounted on the upper side of the arm (4), and the underwater power system is mounted on the lower side of the arm (4), and is kept on the same axis as the air power system; The two arms (4) at the front of the UAV waterproof compartment are connected to the fuselage via a high-torque steering gear (18), and the steering gear is used to achieve large-angle free rotation, and assist the arms to complete the backward folding. The two arms (4) at the rear of the waterproof compartment are connected to the arm connector (19) on the fuselage, and the arms (4) rotate around the arm connector (19) to achieve the downward vertical folding of the arms. The two front arms (4) of the drone arm (4) are used for the drone to closely follow the target and carry out underwater operations; the aerial power system above the drone arm (4) is composed of four sets of brushless motors (2) and matching aerial rotors (1), and is installed closely to the upper surface of the arm (4); The aerial rotor (1) is a 27-inch two-blade propeller; The underwater power system below the drone arm (4) is composed of four sets of underwater thrusters, which are kept on the same axis as the aerial power, and are used to provide the drone with a certain angle of inclination underwater and at the water-air interface, so that the drone can move underwater and at the water-air interface; The underwater power system includes an underwater propeller (3) and a lateral underwater propeller (5), wherein a pair of underwater propellers (3) are installed on the central side below the frame, and the underwater propellers (3) are connected to the machine arm (4); The side underwater thrusters (5) are installed horizontally on both sides below the center of the frame, and are used to increase the underwater navigation speed of the UAV, while ensuring that the UAV hovers at the water-air interface and withstands wind and waves on the water surface, and limiting the rotation of the UAV around the axis.

2. The large-load multi-rotor water-air dual-power cross-medium UAV according to claim 1, characterized in that: The waterproof compartment (7) and the load compartment (8) are both fully enclosed compartments, and the load compartment (8) is located below the waterproof compartment (7); The barometer (17) is externally mounted and used to measure the altitude of the drone in real time and provide it to the drone flight controller. The flight controller obtains an altitude control signal through an internal altitude control algorithm and sends it to the air power system to assist the drone in completing the altitude-fixed movement in the air.

3. The large-load multi-rotor water-air dual-power cross-medium UAV according to claim 2, characterized in that: The UAV waterproof compartment (7) is used to install a battery (9), an electric regulator, a flight control board, cables, a power distribution board (11), a relay, an image transmission and receiver (10), and a camera (14); The battery (9) is connected to the distribution board (11) through a relay, and the distribution board (11) provides processed driving voltage to the flight control board, the electric speed controller, the image transmission and receiver (10), and the camera (14) through cables; the electric speed controller provides driving voltage for the aerial power and underwater power; the relay is responsible for switching the battery, and the image transmission and receiver (10) and the camera (14) are responsible for providing the UAV remote control signal and real-time navigation image information.

4. The large-load multi-rotor water-air dual-power cross-medium UAV according to claim 1, characterized in that: The load compartment (8) is used to carry a large load of at least 10 kg, is supported by a bottom circular ring bracket, and is fixedly connected to the UAV frame by a bottom support plate.

5. The large-load multi-rotor water-air dual-power cross-medium UAV according to claim 1, characterized in that: The unmanned aerial vehicle (UAV) includes a detection instrument, which includes a water depth sensor (15) and a ranging sonar (16). The water depth sensor (15), the ranging sonar (16) and the barometer (17) are controlled by an UAV control system, and the UAV control system adopts a master-slave control mode; the main control board (12) adopts a Pixhawk flight control, and the main control board (12) is connected to an external barometer (17) to provide altitude information for the UAV; the slave control board (13) adopts an STM32 chip, which is connected to the water depth sensor (15) and the ranging sonar (16) to provide the UAV with water-air power switching and underwater depth and altitude information.

6. The large-load multi-rotor water-air dual-power cross-medium UAV according to claim 5, characterized in that: The barometer (17) is externally provided and is used to measure the altitude of the drone in real time, and to assist the drone in completing the altitude-fixed movement in the air; The drone frame is set in an "X" configuration and installed symmetrically at 90 degrees.

7. The large-load multi-rotor water-air dual-power cross-medium UAV according to claim 5, characterized in that: The water depth sensor (15) is an external water depth sensor MS5837, which is installed outside the fully enclosed waterproof compartment (7). The ranging sonar (16) is a ranging sonar DE_WLM36. The water depth sensor (15) is installed below the water depth sensor (15) at a parallel distance of 25 cm and close to the side underwater propeller (5). The ranging sonar (16) is used to obtain underwater height information of the UAV to assist the UAV in completing underwater height-fixing movement.

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