Water-to-air transmedia unmanned aerial vehicles and their flight methods

Abstract

This invention discloses a trans-medium unmanned aerial vehicle (UAV) and its flight method, belonging to the field of UAV technology. The UAV includes a sealed cabin composed of upper and lower sections, symmetrical arms, a tail servo and rudder, left and right servos and elevators, an underwater propulsion system, and various sensors (binocular camera, sonar, water quality sensor, etc.). It achieves aerial flight through a quadcopter mode and underwater navigation through a fixed-wing mode. The control method covers takeoff, aerial flight, air-to-water transition (automatic switching mode for hovering on the water surface), underwater navigation, air-to-water transition, and landing phases. It combines layered rate descent and multi-sensor fusion to determine the status, achieving fully autonomous trans-medium transition. It features a compact structure, reliable sealing, and precise trans-domain control, making it suitable for scenarios such as marine exploration, environmental monitoring, and underwater reconnaissance.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) technology, specifically relating to a water-air cross-medium UAV and its flight method. Background Technology

[0002] Currently, in the field of unmanned aerial vehicles (UAVs), the connection methods and installation structures of their components have a significant impact on the overall performance of UAV devices with complex motion control requirements. Existing UAV mechanical structures have shortcomings in terms of component connection stability, wiring layout rationality, and motion control flexibility, necessitating an optimized UAV mechanical structure to meet practical application needs.

[0003] As the application scenarios of drones continue to expand, the demand for cross-environment operations (such as air-to-water transitions and multi-task payload adaptation) is increasing. For example, publicly available technology CN116494697A is a heavy-load multi-rotor dual-powered cross-medium drone capable of operating across water and air. Although some researchers are studying air-to-water drones, there is still room for improvement in their structure. Traditional drone structures generally have the following shortcomings: limited mode switching, with quadcopter and fixed-wing mode switching relying on manual operation, lacking an efficient and accurate automatic switching mechanism, making it difficult to cope with complex cross-domain tasks; poor sensor adaptability, with unreasonable sensor placement, susceptible to interference from flight attitude and environment (such as water surface fluctuations affecting underwater sensor operation), and a lack of sensor collaborative operation logic in different mission scenarios; and relatively simple flight control, lacking refined control strategies for multi-mode and multi-sensor data fusion during air-to-water transitions and underwater / air flight phases, affecting mission execution accuracy and safety. Summary of the Invention

[0004] The purpose of this invention is to provide a water-air cross-medium unmanned aerial vehicle and its control method, which achieves full-process autonomy of cross-domain flight in the air and underwater through structural optimization and intelligent control, and solves the problems of poor sealing, unstable mode switching and insufficient environmental perception.

[0005] Water-to-air cross-medium unmanned aerial vehicles (UAVs), including:

[0006] The drone consists of an upper and lower cabin, which are fixedly connected by bolts and nuts to form a sealed cabin. Symmetrically arranged on both sides of the upper cabin are the arms, including at least two clockwise and two counter-clockwise arms. Each arm has a mounting hole at its outer end for installing a motor, and a through hole inside the arm for the motor wiring to pass through. A tail servo is located at the rear of the upper cabin and is fixed to the upper cabin via a servo base, connecting to the tail rudder. Left and right servos are located on both sides of the lower cabin, driving the left and right elevators respectively. The left and right elevators, together with the tail rudder, achieve underwater directional control of the drone. A thruster and landing gear are installed at the bottom of the lower cabin; the thruster provides underwater propulsion, and the landing gear supports the drone. Sensors are also integrated onto the drone.

[0007] The sensors of the water-air cross-medium UAV include at least one of the following: binocular camera, water contact sensor, water depth sensor, sonar sensor, water quality sensor, lidar, magnetometer, and ultrasonic altimeter.

[0008] The binocular camera is mounted on the side of the fuselage to acquire underwater images and depth information;

[0009] Water contact sensors are used to detect the contact status between the drone and the water surface;

[0010] A depth sensor is used to measure water depth;

[0011] Sonar sensors are used to acquire seabed topographic data;

[0012] Water quality sensors are used to monitor water quality parameters;

[0013] LiDAR is used to measure water depth and seabed topography;

[0014] Magnetometers are used to detect anomalies in the ocean's magnetic field.

[0015] The binocular camera is mounted on the side of the fuselage and can capture underwater images, including underwater creatures, topography, and underwater facilities. It can be used in marine scientific research, underwater archaeology, and underwater facility monitoring to obtain depth information of the scene for more accurate measurement and positioning.

[0016] A water depth sensor is located on the side of the fuselage to identify the water surface contact status. It is used to detect when the water surface is automatically lowered. The mode switching function can only be activated when the water depth reaches the critical value to prevent accidental activation of the manual control switch.

[0017] Sonar sensors, specifically multibeam echo sounders, can emit multiple beams to simultaneously measure water depth at multiple points, rapidly acquiring seabed topographic data and creating high-precision seabed maps. Side-scan sonar, on the other hand, emits sound waves to both sides and receives reflected signals from the seabed to generate a two-dimensional image of the seabed topography, which can be used to detect seabed obstacles, shipwrecks, pipelines, and other objects. Furthermore, sonar sensors can also be used for underwater target detection and location. By receiving sound waves reflected from targets, they can determine the target's position, distance, and shape, and are commonly used in anti-submarine warfare, underwater search and rescue, and other fields.

[0018] Water quality sensors can monitor parameters such as dissolved oxygen, pH, ammonia nitrogen, nitrite, and water temperature in water bodies in real time, providing data support for marine environmental research, aquaculture, and water pollution monitoring. For example, in aquaculture, monitoring water quality data allows for timely adjustments to farming strategies to ensure the healthy growth of fish. In marine pollution monitoring, it enables the timely detection of water quality anomalies and provides early warnings of pollution events.

[0019] Lidar (Light Detection and Ranging) uses the interaction of a laser beam with water and the seabed to measure water depth and seabed topography. It boasts advantages such as high accuracy, high resolution, and fast measurement speed. It can perform depth measurement in shallow waters and map the waterbed, and can simultaneously acquire land and underwater topographic data, ensuring continuity. It is suitable for topographic surveying areas such as coastlines, rivers, or ponds. Magnetometers are used to detect anomalies in the seabed's magnetic field. By measuring changes in the magnetic properties of seabed rocks and minerals, they infer seabed geological structures, locate potential mineral resources, and can also be used to detect underwater metallic objects such as shipwrecks and unexploded ordnance.

[0020] The water-to-air cross-medium unmanned aerial vehicle (UAV) has an upper and lower cabin forming a sealed structure that houses the controller, inertial measurement unit (IMU), and underwater acoustic positioning system. The controller includes at least a flight control unit module and a power module. The controller and IMU are crucial for ensuring the UAV's continuous, stable, and safe operation in water-based environments. The sealed structure isolates the UAV from moisture and corrosive environments, protecting the core flight control unit and power module.

[0021] This is a trans-medium unmanned aerial vehicle (UAV) with its arms fixed to the upper fuselage by screws. The inner ends of the arms have mounting holes for connection to the upper fuselage, while the outer ends have a rounded shape. The screw fixing and the inner mounting hole design ensure the strength and reliability of the connection between the arms and the fuselage, allowing them to withstand vibrations and loads during flight. The rounded outer end structure helps reduce drag during flight, especially in the air and underwater, improving flight efficiency and endurance.

[0022] The tail servo of the water-to-air cross-medium UAV is fixedly mounted on the servo base. The tail servo is equipped with a cross arm washer. The cross mounting hole at one end of the tail rudder is fastened to the cross arm washer by screws, and the through hole at the other end is connected to the servo base by bolts, thereby enabling the tail rudder to rotate flexibly under the drive of the tail servo.

[0023] This structure enables efficient and reliable directional control, providing a robust yet flexible transmission interface to ensure that the tail servo's power is accurately and with low latency transmitted to the tail rudder, achieving precise, rapid response, and stable control of the UAV's yaw, especially in fixed-wing mode. In this invention, fixed-wing mode specifically refers to the specific operating mode of underwater navigation utilizing propellers and control surfaces.

[0024] In this amphibious unmanned aerial vehicle (UAV), the left and right elevators are connected to the left and right servo motors respectively via elevator pads to achieve elevation control. This connection method enables efficient and reliable pitch and roll control. The elevator pads, acting as connectors, ensure that the power output from the left and right servo motors can stably and precisely drive the left and right elevators to deflect. This is the foundation for achieving pitch and roll control, especially during underwater navigation, in fixed-wing mode (where the propellers of the bottom thrusters provide thrust to propel the UAV underwater, with the elevators on both sides controlling surfacing and descent, and the tail rudder controlling left and right directions). It is crucial for attitude stability and maneuverability during underwater navigation.

[0025] The water-to-air cross-medium UAV has inflatable airbags arranged circumferentially on the bottom side of the tripod. When the UAV's remote control signal is interrupted for more than 30 seconds or the inertial measurement unit detects a tilt angle greater than 15°, the controller triggers an ignition command to control the airbags to inflate.

[0026] A flight method for a water-air cross-medium unmanned aerial vehicle (UAV) includes the following stages:

[0027] Takeoff phase: The drone initiates the automatic takeoff mode program and flies to a specific altitude above the ground to hover;

[0028] During the aerial flight phase: Manually control the drone to fly parallel above the landing point, with a flight speed range of 0-15m / s;

[0029] Air-water transition phase: Manually operate the drone to descend. When the ultrasonic altimeter detects that the drone is at a specific height above the water surface, the flight control unit module automatically commands the drone to hover. The drone initiates automatic landing mode, the motors slow down to idle speed, and the drone enters a hovering state on the water surface. Adjust the angles of the left and right elevators so that the bottom surfaces of the left and right elevators are parallel to the bottom surface of the lower cabin. Adjust the angle of the tail rudder so that the center line of the top surface of the tail rudder coincides with the center line a of the top surface of the upper cabin.

[0030] Underwater diving phase: Activate the thrusters and control the left and right elevators to deflect forward at a specific angle, allowing the drone to dive underwater and navigate.

[0031] Water-air transition phase: Manually control the drone to hover over the water surface, start the automatic take-off mode program with the remote controller, take off and hover at a specific height above the water surface, and then fly parallel to the landing point.

[0032] Landing phase: The drone initiates the automatic landing procedure to achieve a smooth landing.

[0033] The quadcopter mode refers to the drone flying in the air driven by motors on its four arms, similar to the flight mode of a typical quadcopter drone. The fixed-wing mode uses propellers on its bottom thrusters to propel the drone underwater, with elevators on both sides controlling surfacing and descent, and a rudder at the tail controlling left and right direction. This flight control method enables full-process cross-domain flight operations, systematically standardizing the complete flight mission flow from takeoff, air flight, water entry (air-water transition), underwater navigation, water exit (water-air transition) to final landing. It clearly defines the application scenarios for quadcopter mode (air flight, takeoff and landing) and fixed-wing mode (underwater navigation), fully utilizing the advantages of each mode in its respective medium. Combining automatic (e.g., takeoff and landing) and manual control, it provides operators with clear and controllable mission execution steps, reducing operational complexity and the risk of errors. It specifically defines two key transition stages: air-water transition and water-air transition, and clearly defines the water surface suspension state as the transition platform, providing a methodological guarantee for safe and reliable mode switching.

[0034] By using an ultrasonic altimeter to hover at a specific height (e.g., 1m), the drone approaches the water surface in a controllable manner. The automatic landing mode is then activated via remote control, and the quadcopter motors are reduced to idle speed, allowing the drone to smoothly touch the water surface and achieve a stable hovering state. The fixed-wing control surfaces are then adjusted to the neutral position to prepare for the upcoming switch to fixed-wing mode. This process automates or semi-automates the operation from hovering in the air to hovering on the water surface, and then to mode switching. It significantly improves the accuracy, stability, and safety of the mode switching process and reduces human error.

[0035] A flight method for a water-air cross-medium unmanned aerial vehicle (UAV) involves reducing the descent rate in stages according to a preset deceleration logic during the air-water transition phase or landing phase.

[0036] When the height is greater than 5m, the descent rate is 0.8-1m / s;

[0037] When 5m > height > 1m, the descent rate is 0.3-0.5m / s;

[0038] When 1m > height > 0.3m, the descent rate is 0.1-0.2m / s;

[0039] The landing status is determined by combining sensor data, and the judgment conditions include sudden changes in accelerometer altitude data, ultrasonic altimeter readings of less than 0.1m, or a decrease in motor current of more than 30%.

[0040] After landing, the motor linearly slows down to idle speed, and the landing point coordinates are recorded.

[0041] This method refines the specific operations of the UAV's automatic landing phase, controlling the descent rate according to altitude levels: faster descent at higher altitudes and slower descent at lower altitudes. This effectively avoids the risks associated with high-speed impacts, ensuring a smooth landing or water landing and protecting the airframe structure and payload. Utilizing multi-sensor fusion to determine the ground / water contact status significantly improves the accuracy and reliability of detection, avoiding false alarms such as minor disturbances or missed detections. It ensures that power is only shut off after safe contact is confirmed. This method is applicable to both land and water landings, demonstrating strong versatility. The layered rate control strategy is the core mechanism ensuring safety at different altitudes.

[0042] The advantages of this invention are as follows: through innovative upper and lower sealed cabin design, precise integrated quadcopter air and fixed-wing underwater dual-mode system, and systematic safety switching process, the reliability and flight stability of the UAV in safe switching between air and water media are significantly improved; at the same time, its optimized drive structure, such as low-drag arms, precision servo motor connectors, and all-around sensing array binocular cameras, sonar, and water quality sensors, greatly enhances the robust maneuverability and multi-dimensional detection capabilities in underwater environments; in addition, multiple active / passive safety mechanisms for sealing protection and automatic airbag triggering enable efficient and reliable execution of complex cross-domain tasks. Attached Figure Description

[0043] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the overall device structure of the present invention;

[0045] Figure 2 This is an exploded view of the overall components of the present invention;

[0046] Figure 3 This is a schematic diagram of the clockwise and counterclockwise rotating arms of the present invention;

[0047] Figure 4 This is a top view of the overall device of the present invention;

[0048] Figure 5 This is a side view of the overall device of the present invention;

[0049] Figure 6 This is a schematic diagram of the servo base, tail rudder, and cross arm gasket of the present invention;

[0050] Figure 7 This is a schematic diagram of the elevator and elevator gasket of the present invention;

[0051] Figure 8 This is a schematic diagram of the tail rudder installation state of the present invention;

[0052] Figure 9 This is a schematic diagram of the airbag of the present invention;

[0053] Figure 10 This is a schematic diagram of the process of each stage in Embodiment 5 of the present invention;

[0054] Figure 11 This is a schematic diagram of the automatic takeoff mode program flow of the present invention;

[0055] Figure 12 This is a schematic diagram of the process of Embodiment 4 of the present invention.

[0056] Attached diagram descriptions: 1-Upper hull, 2-Lower hull, 3-Arm, 31-Current-rotating arm, 32-Reverse-rotating arm, 4-Motor, 6-Tail servo, 7-Thruster, 8-Legs, 10-Airbag, 51-Left servo, 52-Right servo, 51a-Left elevator, 52a-Right elevator, 53-Elevator pad, 61-Servo base, 62-Tail rudder, 63-Cross arm pad, 64-Bolt, 81-Opening, 91-Binocular camera, 92-Water contact sensor. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0059] Example 1:

[0060] See attached document Figure 1 Appendix Figure 2 As shown, two clockwise rotating arms 31 and two counter-clockwise rotating arms 32 are symmetrically installed on both sides of the upper hull 1, and are fixed with countersunk head Phillips screws. The outer ends of the arms 3 have an arc-shaped structure to reduce fluid resistance. The inner end has a through hole for the motor wiring, and the outer end has four mounting holes to fix the motor 4, realizing a quadcopter power layout. The bottom of the lower hull 2 ​​is equipped with a thruster 7 and four landing gears 8. The thruster 7 provides underwater thrust, and the landing gears 8 ensure take-off and landing stability on water or land. The bottom of the landing gears 8 has a hollow section 81 for drainage and installation of auxiliary devices.

[0061] See attached document Figure 6 Appendix Figure 8 As shown, regarding the servo control system, the tail servo 6 is fixed to the stern of the upper hull 1 via the servo base 61, and the tail rudder 62 is connected to the tail servo 6 via the cross arm pad 63 to achieve precise yaw control. The left servo 51 and the right servo 52 drive the elevator pad 53, causing the left elevator 51a and the right elevator 52a to deflect, controlling pitch and roll.

[0062] See attached document Figure 1 Appendix Figure 2 As shown, the binocular camera 91 is mounted on the side of the fuselage, enabling underwater image capture of underwater life, topography, underwater facilities, and other images for use in marine scientific research, underwater archaeology, and underwater facility monitoring. It acquires depth information of the scene and enables more accurate measurement and positioning. The water contact sensor 92, located on the side of the fuselage, identifies the water surface contact status and is used for detection during automatic descent into the water. The mode switching function is activated only when the detected water depth reaches a critical value to prevent accidental manual switching.

[0063] See attached document Figure 2 As shown, optionally, the UAV can be equipped with a sonar sensor at the bottom of the lower hull 2. The sonar sensor can be a multibeam echo sounder. A multibeam echo sounder can simultaneously measure water depth at multiple points, quickly acquire seabed topographic data, and create high-precision seabed topographic maps. Side-scan sonar, by emitting sound waves to both sides and receiving reflected signals from the seabed, generates a two-dimensional image of the seabed topography, which can be used to detect seabed obstacles, shipwrecks, pipelines, and other objects. Furthermore, sonar sensors can also be used for underwater target detection and positioning. By receiving sound waves reflected from targets, they can determine the target's position, distance, and shape, and are commonly used in anti-submarine warfare, underwater search and rescue, and other fields.

[0064] See attached document Figure 2As shown, optionally, the UAV can be equipped with a water quality sensor at the bottom of the lower hull 2, which can monitor parameters such as dissolved oxygen, pH, ammonia nitrogen, nitrite, and water temperature in the water in real time, providing data support for marine environmental research, aquaculture, and water pollution monitoring. For example, in aquaculture, by monitoring water quality data, aquaculture strategies can be adjusted in a timely manner to ensure the healthy growth of fish; in marine pollution monitoring, water quality anomalies can be detected in a timely manner, and pollution events can be warned.

[0065] See attached document Figure 2 As shown, optionally, the UAV can be equipped with a lidar at the bottom of the lower hull 2. Utilizing the interaction between the laser beam and the water and seabed, it measures water depth and seabed topography. It boasts advantages such as high accuracy, high resolution, and fast measurement speed. It can perform depth measurement in shallow water areas and map the waterbed, and can simultaneously acquire land and underwater topographic data, ensuring continuity. It is suitable for topographic surveying of areas such as coastlines, rivers, or ponds.

[0066] See attached document Figure 2 As shown, optionally, the UAV can be equipped with a magnetometer at the bottom of the lower hull 2 ​​to infer the geological structure of the seabed by measuring the magnetic changes of seabed rocks and minerals, and to search for potential mineral resources. It can also be used to detect underwater metal objects, such as shipwrecks and unexploded ordnance.

[0067] See attached document Figure 2 As shown, optionally, the drone can be equipped with an ultrasonic altimeter at the bottom of the lower cabin 2 to control the drone's flight by measuring the drone's height above the bottom or water surface.

[0068] Example 2:

[0069] See attached document Figure 11 As shown, this embodiment describes the automatic takeoff mode procedure for a UAV. Automatic takeoff mode is activated via ground station command, remote controller mode switch, or system initiation. After activation, the "set takeoff position" operation is performed first: the system records the initial position of the UAV, which serves as the mission starting point, and all subsequent target points are calculated based on this coordinate system. Then, an external request is sent to check the validity of the target point. If valid, the target point data sent by an external system (such as a ground station or command center) is used, and the "use external request target altitude" process is initiated; if invalid, the default altitude logic is enabled, and the "calculate default altitude = current position altitude + set altitude" process is executed. The set altitude can be configured in the ground station, for example, set to 1m.

[0070] When the target point is valid, use the externally requested target altitude to determine whether the target altitude is less than the current altitude. If the target altitude is less than the current altitude, the target altitude is directly forced to be set to the current altitude (to prevent the drone from flying downwards and ensure safety). If the target altitude is greater than or equal to the set altitude, the externally requested target altitude is retained, and the process proceeds to "Set Takeoff Mission".

[0071] When the target point is invalid, the default altitude is calculated as the current position altitude plus the set altitude to ensure that the drone climbs to at least a safe altitude. The default altitude is recorded in the log, and the system log is marked as using the default altitude for easy troubleshooting and debugging afterward.

[0072] Regardless of how the altitude logic branches, it ultimately enters the "Set Takeoff Mission" stage: The system encapsulates the target point (including coordinates and altitude), flight mode (automatic takeoff), and safety parameters (such as obstacle clearance) into a mission package. This mission package is sent to the flight control module via an internal communication bus (such as uORB). The flight control module can call position control algorithms (such as PID and MPC) and, in conjunction with IMU data, control the UAV to fly towards the target point, providing real-time feedback on flight status (position error, altitude error, speed, etc.). When executing a takeoff mission, it checks if a new target point has appeared. If so, it resets the takeoff position; otherwise, it checks if the target point has been reached.

[0073] Example 3:

[0074] See attached document Figure 1 Appendix Figure 2 Appendix Figure 8 As shown, regarding the mode switching control scheme for the UAV, when the UAV is transitioning between air and water (entering water from the air), when the ultrasonic altimeter detects a distance of 1m from the water surface, the flight control system automatically sends a command, the UAV hovers, and the remote controller initiates the automatic landing mode. The quadcopter motor 4 slows down to idle speed, enters a hovering state on the water surface, and adjusts the fixed-wing control surfaces to the center position to complete the mode switch from quadcopter to fixed-wing. The fixed-wing control surfaces include the left rudder 51, the right rudder 52, and the tail rudder 62, and their angles are automatically adjusted to the center position of rotation.

[0075] When the drone is transitioning between water and air, manually control the drone to hover from the water to the surface, then send a mode switching command via the remote controller to switch from fixed-wing mode to quadcopter mode. Use the remote controller to start the automatic take-off mode program, and hover when the ultrasonic altimeter detects a distance of 1m from the water surface.

[0076] Example 4:

[0077] This embodiment describes in detail the mode switching control process of a water-air cross-medium UAV in a water surface patrol mission. The goal of the UAV in this embodiment is to take off from the take-off and landing point, conduct aerial patrol and monitoring (quadcopter mode), then enter the water to monitor the activity of fish farmed underwater (fixed-wing mode), and then exit the water to return to base.

[0078] See attached document Figure 1 As shown, when the UAV arrives above the target fish farming area, and the ultrasonic altimeter detects a distance of 1.0m ± 0.1m from the water surface, the flight control system automatically freezes the attitude (roll angle ≤ 5°, pitch angle = 0°), the binocular camera 91 confirms there are no obstacles on the water surface, and the water contact sensor 92 is pre-activated. The remote controller initiates automatic descent mode, implementing layered rate control. When the UAV's altitude above the water point is greater than 5m, the descent rate is 1m / s, allowing the UAV to quickly approach the water surface; when the altitude is between 1-5m, the descent rate is 0.5m / s to resist wave disturbances when approaching the water surface; when the UAV's altitude is between 0.3-1m, the descent rate is 0.2m / s for impact buffering. The UAV's internal accelerometer detects a sudden change in accelerometer readings, exceeding 1.2g, and the water contact sensor 92 remains active for 0.5s, indicating successful hovering. Once the hovering is successfully determined, the quadcopter power is turned off, motor 4 slows down to idle, clockwise arm 31 and counterclockwise arm 32 stop rotating, left elevator 51a and right elevator 52a are reset to the center position via elevator pad 53, and thruster 7 is powered on and ready to operate. Afterwards, the UAV adjusts its angle using left elevator 51a, right elevator 52a and tail rudder 62 to enter the water, while simultaneously monitoring the activity of farmed fish underwater using binocular camera 91.

[0079] After monitoring fish activity, the staff maneuvered the drone to the water's surface. The thruster 7 was de-throttled, and the tail rudder 62 returned to center via the crossarm pad 63. The quadcopter motor 4 gradually increased the throttle to 10%. The remote controller then triggered the takeoff command. The ultrasonic altimeter monitored the altitude above the water. When the drone was within 0-0.8m above the water surface, the vertical ascent rate was 0.3m / s. This speed prevented water adhesion. Once the drone was above 0.8m above the water surface, it switched to the standard takeoff procedure, hovering at a height of 1m. The magnetometer calibrated the azimuth angle, completing the mode transition.

[0080] Example 5:

[0081] See attached document Figure 1As shown, this embodiment describes in detail a complete multi-segment flight control process of the UAV based on the aforementioned air-sea cross-medium UAV flight control scheme. The starting point is a land-based take-off and landing point. The aerial cruising segment (altitude 50m, speed 10m / s) covers the coastline. The surface monitoring segment (suspended state) performs water quality sampling. The underwater reconnaissance segment (depth 5-10m) scans the seabed topography. The onboard sensors include a binocular camera 91, a water quality sensor, a sonar sensor, and a lidar. The operator performs a self-test on the flight control unit module, primarily verifying the battery charge (>80%), the inertial measurement unit (IMU) calibration status, and sensor connectivity. This ensures the sealed cabin (upper cabin 1 and lower cabin 2 are connected by bolts and nuts) meets waterproofing standards, preventing moisture corrosion of the core electronic modules.

[0082] Automatic Takeoff Execution: The user triggers "Automatic Takeoff Mode" with a single button press on the remote control. The flight control system initializes the PID altitude controller, setting the target altitude to 1m. The quadcopter motors (installed on the clockwise and counterclockwise arms 31 and 32) gradually increase speed, maintaining a vertical ascent attitude based on IMU and underwater acoustic positioning system data. Upon reaching the target altitude, the ultrasonic altimeter confirms a distance of 1m from the ground, and the system switches to hover mode, recording the takeoff position coordinates. The arc-shaped structure at the outer end of the arms reduces air resistance and improves energy efficiency.

[0083] See attached document Figure 1 As shown, during the flight phase: the operator switches to manual control and adjusts the quadcopter motor speed via remote control, maintaining the flight speed within the range of 0-15 m / s. The binocular camera 91 captures real-time coastline images, combining visual localization and mapping (SLAM) algorithms to achieve obstacle avoidance (accuracy ±0.3m). By integrating IMU quaternion calculations and underwater acoustic positioning system data, the system automatically compensates for roll angle when encountering crosswinds, maintaining flight stability. The aerial cruise lasts 10 minutes, completing the initial terrain mapping.

[0084] Air-to-water transition phase: Upon reaching the mission area, the drone automatically hovers when the ultrasonic altimeter detects a distance of 1m from the water surface. The remote controller activates "automatic descent mode," and the flight control system loads layered descent rate parameters: 1m / s at altitude > 5m; 0.5m / s at altitude between 1-5m; and 0.2m / s at altitude between 0.3-1m. After water contact sensor 92 confirms water contact, the quadcopter motor 4 slows to idle (5% throttle), and the drone enters a stable hovering state. The fixed-wing control surfaces (left elevator 51a and right elevator 52a connected via elevator pad 53) are adjusted to the neutral position, aligning the centerline of the top surface of the tail rudder 62 with the centerline a of the top surface of the upper fuselage 1. The thrusters 7 are activated, preparing for underwater navigation.

[0085] Descent and Navigation Control: With the thruster 7 throttle at 70%, the elevator 51a is driven forward by the left rudder 51 and right rudder 52, deflecting 45° and triggering the descent. The water contact sensor 92 monitors the depth in real time, ensuring the descent rate is ≤0.5m / s. The tail rudder 62 adjusts the course under the drive of the tail rudder 6, the sonar sensor scans the seabed and reefs, the lidar generates a high-precision topographic map (resolution ±0.1m), the water quality sensor collects samples, and the data is transmitted to the ground station.

[0086] Water-to-air transition phase: Manually control the drone to hover above the water surface. The remote controller sends a "mode switch command," the fixed-wing control surfaces reset, and quadcopter motor 4 is reactivated. Initiate the automatic takeoff mode program, ascend vertically to a height of 1m above the water surface and hover (ultrasonic altimeter calibration), preparing for return.

[0087] Landing Phase: After returning to the takeoff and landing point, automatic landing is triggered: layered rate logic is reused (altitude > 5m: 1m / s; 5m > altitude > 1m: 0.5m / s; 1m > altitude > 0.3m: 0.2m / s). Multi-sensor fusion determines whether landing has occurred. If the accelerometer detects a sudden change in measurement data (>1.2g) or the ultrasonic altimeter confirms an altitude <0.1m, the drone can be considered to have landed. After landing, the motor thrust linearly decreases to idle speed, coordinates are recorded and a status log is published, and landing gear 8 absorbs the impact, ensuring a smooth landing.

[0088] Example 6:

[0089] Optionally, an inflatable airbag 10 is circumferentially arranged on the bottom side of the landing gear 8 of the water-to-air cross-medium UAV. The airbag 10 is connected to the landing gear 8 via a snap-fit ​​mechanism and is installed next to the opening 81 of the landing gear 8. An ignition device is integrated inside the airbag 10 and is electrically linked to the main controller inside the sealed cabin (composed of an upper cabin 1 and a lower cabin 2 bolted together) via a waterproof cable. When the UAV is operating underwater, if the remote control signal is interrupted for more than 30 seconds, the controller automatically triggers an ignition command, causing the solid gas-generating agent to react instantaneously. The airbag 10 inflates to a diameter of 40cm within 0.3 seconds, generating a positive buoyancy of over 5kg to propel the UAV to the surface. Simultaneously activated, a buzzer inside the UAV cabin sounds, assisting personnel in positioning and recovery. The airbag 10 is installed at the opening 81 of the landing gear 8. This opening 81 can also serve as a drainage channel for fluid flow. There is a gap between the airbag 10 and the tripod 8. When the airbag 10 is submerged in water or during emergency expansion, the water that rushes into the gap is discharged through the perforation 81 under the pressure of the airbag 10's expansion. Actual test data shows that this design reduces the peak water pressure in the gap by 62%, effectively eliminating the shear stress on the wall of the airbag 10 caused by local water pressure.

[0090] Optionally, during the water-to-air transition phase, if the aircraft encounters surface turbulence (IMU detects tilt angle > 15°), the operator can manually trigger the airbag 10 to ignite. The inflated airbag 10 forms a buoyancy band, increasing the draft by 20cm and reducing center of gravity fluctuations, limiting the roll angle to within ±8°. The controller forces a 5-second delay before allowing the quadcopter motor 4 to start, preventing damage to the high-speed rotating blades from waves. Actual test data shows that this design reduces the water takeoff and landing failure rate by 92%, maintaining a high switching success rate even in extreme wave conditions. The airbag 10 system is deeply coupled with the flight control unit module, with interlocking logic between the ignition command and power start / stop to ensure that emergency operations do not interfere with normal flight modes.

[0091] The embodiments and / or implementation methods described above are merely preferred embodiments and / or implementation methods for implementing the technology of the present invention, and are not intended to limit the implementation methods of the technology of the present invention in any way. Any person skilled in the art may make some modifications to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but these should still be regarded as the technology or embodiments that are substantially the same as the present invention.

[0092] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A water-air cross-medium unmanned aerial vehicle, characterized in that, include: The upper compartment (1) and the lower compartment (2) are fixedly connected by bolts and nuts, forming a sealed compartment inside; The arms (3) symmetrically arranged on both sides of the upper cabin (1) include at least two clockwise rotating arms (31) and two counterclockwise rotating arms (32), and each arm (3) has a mounting hole at its outer end for mounting a motor (4); The tail servo (6) is located at the rear of the upper hull (1). The tail servo (6) is fixed to the upper hull (1) via a servo base (61). The tail servo (6) is connected to the tail rudder (62) to achieve directional control. The left rudder (51) and right rudder (52) located on both sides of the lower hull (2) are used to drive the left elevator (51a) and right elevator (52a) respectively. The thruster (7) and the footrest (8) are installed at the bottom of the lower hull (2). And sensors integrated into drones; The sealed cabin structure formed by the upper cabin (1) and the lower cabin (2) houses a controller, an inertial measurement unit and a positioning system. The controller includes at least a flight control unit module and a power supply module, and the inertial measurement unit includes an accelerometer and a gyroscope. The tripod (8) has an inflatable airbag (10) arranged circumferentially on the bottom side. When the drone remote control signal is interrupted for more than 30 seconds or the inertial measurement unit detects an inclination angle of >15°, the controller triggers an ignition command to control the airbag (10) to inflate. The stand (8) has a perforated part (81), and there is a gap between the airbag (10) and the stand (8). When the airbag (10) is submerged in water or during emergency expansion, the water that flows into the gap is discharged through the perforated part (81) under the pressure of the expansion of the airbag (10).

2. The water-air transmedium unmanned aerial vehicle according to claim 1, characterized in that, The sensors include at least two of the following: a binocular camera (91), a water contact sensor (92), a water depth sensor, a sonar sensor, a water quality sensor, a lidar, a magnetometer, and an ultrasonic altimeter.

3. The water-air transmedium unmanned aerial vehicle according to claim 2, characterized in that, The binocular camera (91) is installed on the side of the fuselage consisting of the upper hull (1) and the lower hull (2) to acquire underwater images and depth information; The water contact sensor (92) is installed on the side of the lower cabin (2) to detect the contact status between the UAV and the water surface; The water depth sensor is used to measure water depth; The sonar sensor is used to acquire seabed topographic data; The water quality sensor is used to monitor water quality parameters; The lidar is used to measure water depth and seabed topography; The magnetometer is used to detect anomalies in the ocean's magnetic field.

4. The water-air transmedium unmanned aerial vehicle according to claim 1, characterized in that, The arm (3) is fixed to the upper cabin (1) by screws. The inner end of the arm (3) is provided with an installation hole for connecting to the upper cabin (1). The outer end of the arm (3) has an arc-shaped structure.

5. The water-air transmedium unmanned aerial vehicle according to claim 1, characterized in that, The tail servo (6) is fixedly installed on the servo base (61). A cross arm washer (63) is installed at the bottom of the tail servo (6). The cross mounting hole at one end of the tail rudder (62) is fastened to the cross arm washer (63) by screws. The through hole at the other end is connected to the servo base (61) by bolts (64), thereby realizing the flexible rotation of the tail rudder (62) under the drive of the tail servo (6).

6. The water-air transmedium unmanned aerial vehicle according to claim 1, characterized in that, The left elevator (51a) and the right elevator (52a) are connected to the left servo motor (51) and the right servo motor (52) respectively through elevator pads (53) to achieve elevator control.

7. A flight method for a water-air cross-medium unmanned aerial vehicle, characterized in that, The unmanned aerial vehicle (UAV) is any one of claims 1-6, and the flight method includes the following stages: Takeoff phase: The drone initiates the automatic takeoff mode program and flies to a specific altitude above the ground to hover; During the aerial flight phase: Manually control the drone to fly parallel above the landing point, with a flight speed range of 0-15m / s; Air-water transition phase: Manually operate the drone to descend. When the ultrasonic altimeter detects that the drone is at a specific height above the water surface, the flight control unit module automatically instructs the drone to hover. The drone starts the automatic landing mode, the motor speed is reduced to idle speed, and the drone enters the water surface hovering state. Adjust the angle of the left elevator (51a) and the right elevator (52a) so that the bottom surface of the left elevator (51a) and the right elevator (52a) is parallel to the bottom surface of the lower cabin (2). Adjust the angle of the tail rudder (62) so that the center line of the top surface of the tail rudder (62) coincides with the center line a of the top surface of the upper cabin (1). Underwater diving phase: Activate the thrusters (7) and control the left elevator (51a) and right elevator (52a) to deflect forward by a specific angle, so that the UAV can dive underwater and sail. Water-air transition phase: Manually control the drone to hover over the water surface, start the automatic take-off mode program with the remote controller, take off and hover at a specific height above the water surface, and then fly parallel to the landing point. Landing phase: The drone initiates the automatic landing procedure to achieve a smooth landing.

8. The flight method of the water-air cross-medium UAV according to claim 7, characterized in that, The air-water transition phase or landing phase reduces the descent rate in stages according to a preset deceleration logic: When the height is greater than 5m, the descent rate is 0.8-1m / s; When 5m > height > 1m, the descent rate is 0.3-0.5m / s; When 1m > height > 0.3m, the descent rate is 0.1-0.2m / s; The landing status is determined by combining sensor data. When the accelerometer measurement data changes abruptly or the ultrasonic altimeter measures a height of less than 0.1m, it is determined that the drone has landed. After landing, the controller records the landing point coordinates.

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