Unmanned aerial vehicle airbag amphibious system and method

Abstract

The application discloses an unmanned aerial vehicle airbag type water and land take-off and landing system and method, relates to the technical field of unmanned aerial vehicle take-off and landing devices and flight control, and the unmanned aerial vehicle airbag type water and land take-off and landing system comprises a machine body, a skid type airbag landing gear system arranged below the machine body and an airbag management controller, the skid type airbag landing gear system comprises a skid type multi-cavity airbag assembly, a shape fixing tensioning piece, and a gas charging and discharging execution unit and a sensing unit, the skid type multi-cavity airbag assembly comprises at least two independent air cavities, the sensing unit is used for acquiring pressure information and water contact state information of each air cavity, the airbag management controller determines the gas adjusting amount of each air cavity according to the target draught and the pressure information, the skid type airbag landing gear system is controlled to convert among multiple states, the unmanned aerial vehicle can actively adjust the gas amount of each cavity according to load change and sea state disturbance, and therefore, dynamic conversion among water surface floating, sliding, full sliding and cruising folding states can be realized.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) take-off and landing devices and flight control technology, specifically to an airbag-type amphibious take-off and landing system and method for UAVs. Background Technology

[0002] Currently, there is a strong demand for drones in scenarios such as marine observation, sea surface patrol, and island and reef resupply. These scenarios often lack available runways, requiring drones to be able to take off and land on various platforms such as the sea surface, islands and reefs, and floating platforms, and to maintain operational capabilities in sea conditions with varying wave heights. Existing take-off and landing devices are insufficient to meet these requirements.

[0003] In existing technologies, one type of solution uses a fixed float landing gear, with floats or buoys of fixed volume installed under the fuselage. This type of solution has an unadjustable displacement volume, resulting in a fixed draft after landing; under the influence of waves, it experiences severe rolling and pitching, and splash can easily enter the rotor; even slightly high waves can render it unusable; the floats have a large and unchangeable wetted area, lacking the ability to glide on the water surface, and cannot be rearranged for takeoff by water maneuvering or to avoid waves.

[0004] Another type of solution is the hull-type configuration, which relies on the fuselage to contact the water surface to accelerate and generate hydrodynamic lift to leave the water. It needs to overcome the sliding resistance and places high demands on the sliding distance and power. This type of configuration is only suitable for water surfaces and cannot take off and land on land, making it difficult to meet the requirements of multi-platform compatibility.

[0005] Another approach proposes inflatable and deflated air-float bodies, such as using an air pump to inflate or deflate tires to achieve take-off and landing on the water. In this type of solution, inflation and deflation are only used to switch between buoyancy and non-buoyancy. The draft and waterline shape after landing remain fixed: regardless of changes in load, sea state, or stage of water movement, the immersion depth cannot be actively adjusted, and the surface resistance characteristics are also fixed.

[0006] In summary, the existing technology has the following shortcomings: the draft is fixed after landing and cannot be adjusted according to load and sea state, and the attitude is uncontrollable in waves; it does not have the ability to glide and maneuver on the water surface, and cannot rearrange the takeoff course or avoid waves; water surface takeoff and landing and land takeoff and landing cannot be compatible with the same set of landing gear; and it lacks emergency floating and self-righting capabilities.

[0007] Therefore, it is necessary to develop and design an airbag-type amphibious take-off and landing system and method for unmanned aerial vehicles (UAVs) to solve the above-mentioned problems, which are technical issues that urgently need to be addressed by those skilled in the art. Summary of the Invention

[0008] To address the aforementioned issues, this invention provides an airbag-type amphibious takeoff and landing system and method for unmanned aerial vehicles (UAVs), enabling the UAV to actively adjust the gas volume in each chamber according to load changes and sea state disturbances, thereby dynamically switching between floating, gliding, full gliding, and cruise retracted states.

[0009] To achieve the above objectives, the present invention provides the following solution: A UAV airbag-type amphibious takeoff and landing system includes a fuselage, a power unit and a flight controller mounted on the fuselage, and a skid-type airbag landing gear system and an airbag management controller mounted below the fuselage. The skid-type airbag landing gear system includes a skid-type multi-chamber airbag assembly, a shape-fixing tensioning member mounted on the skid-type multi-chamber airbag assembly for maintaining the shape of the skid-type multi-chamber airbag assembly, and an inflation / deflation actuator and a sensing unit mounted inside the skid-type multi-chamber airbag assembly. The skid-type multi-chamber airbag assembly includes... The system comprises at least two independent air chambers. The sensing unit is used to acquire pressure information and water contact status information for each air chamber. The airbag management controller is communicatively connected to the inflation / deflation execution unit, the sensing unit, and the flight controller. The airbag management controller determines the gas regulation amount for each air chamber based on the target draft and the pressure information, and performs closed-loop regulation of the gas amount in each air chamber, thereby enabling the skid-type airbag landing gear system to controllably switch between water-floating, water-gliding, hydrofoil-gliding, and cruise-folded states.

[0010] Preferably, at least two skid-type multi-chamber airbag assemblies are provided and spaced apart along the wingspan direction of the fuselage. When fully inflated, the skid-type multi-chamber airbag assembly takes the shape of a skid under the limiting action of the shaping tensioner, forming a flat-bottomed sliding surface, a sidewall connected to the flat-bottomed sliding surface and extending in a direction away from and upward from the central axis of the fuselage, and a bow upturned section connected to the flat-bottomed sliding surface.

[0011] Preferably, the skid-type multi-chamber airbag assembly includes at least two air chambers, which are arranged along the length of the body.

[0012] Preferably, the shaping tensioning member includes tensioning cables passing through the top and bottom of the multi-chamber airbag assembly, and the tensioning cables extend inside the skid-type multi-chamber airbag assembly along a direction parallel to the wingspan of the fuselage and perpendicular to the wingspan of the fuselage, respectively.

[0013] Preferably, the inflation / deflation execution unit includes a miniature air pump, a solenoid valve assembly connected to the miniature air pump, and a pipeline for connecting the miniature air pump and the solenoid valve assembly. The solenoid valve assembly is connected to the air chamber and the miniature air pump through the pipeline.

[0014] Preferably, the skid-type airbag landing gear system further includes a landing strut disposed between the skid-type multi-chamber airbag assembly and the fuselage. A skid beam extending along the length of the fuselage is disposed between the landing strut and the multi-chamber airbag assembly. The skid beam is connected to the bottom surface of the skid-type multi-chamber airbag assembly, so that when the skid-type multi-chamber airbag assembly is fully deflated, it covers the lower section of the skid beam and the landing strut, forming a low-frontal area converged and rectified shape.

[0015] This invention also discloses a method for UAV airbag-type amphibious takeoff and landing, applied to the aforementioned UAV airbag-type amphibious takeoff and landing system, comprising the following steps: The target draft is set according to the working mode, which includes floating on the water surface, gliding on the water surface, gliding with hydrofoil, and cruising and retracting. The gas volume in each gas chamber is adjusted in a closed loop by the inflation / deflation unit so that the actual draft follows the target draft. During water gliding, the target draft is switched between a fully inflated water gliding state and a partially deflated hydrofoil gliding state according to the gliding speed.

[0016] Preferably, the target draft of the hydrofoil in the gliding state is determined by the hydrofoil immersion margin.

[0017] Preferably, the closed-loop regulation adopts a cascade structure: the deviation between the actual draft and the target draft is used by a PID controller and superimposed with the air chamber pressure feedforward value calculated offline based on the buoyancy balance relationship to generate an air chamber pressure reference value; the deviation between the air chamber pressure reference value and the actual pressure value in the air chamber is used by a pressure loop PID controller to generate a command and control the inflation / deflation execution unit to perform inflation / deflation operations on the air chamber.

[0018] Preferably, the actual draft is determined by the pressure information and water contact status information of each air chamber.

[0019] The present invention achieves the following technical effects compared to the prior art: By integrating sensing units and inflation / deflation execution units into the airbag management controller, and combining the shaping tensioner to precisely maintain the skid-shaped hydrodynamic shape, closed-loop control of the pressure in each independent air chamber is achieved. This enables the UAV to actively adjust the gas volume in each chamber according to load changes and sea state disturbances, thereby dynamically switching between floating, gliding, full gliding, and cruise retracted states. This not only significantly suppresses pitch and roll in waves, but also retracts the airbags during the cruise phase to reduce flight aerodynamic drag. At the same time, relying on multi-chamber physical isolation redundancy and active asymmetric inflation mechanism, it has emergency self-righting capability, thus significantly improving the UAV's survivability, mission adaptability, and range endurance in complex environments such as deep seas and islands. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Appendix Figure 1 This is a system block diagram of the skid-type airbag landing gear system in some embodiments of the present invention; Appendix Figure 2 This is a schematic diagram showing the shape of the airbag as a fully inflated skid (corresponding to the floating state and the gliding state on the water surface) in some embodiments of the present invention; Appendix Figure 3 This is a schematic diagram showing the shape of the airbag as a hydrofoil (corresponding to the hydrofoil gliding state) in some embodiments of the present invention; Appendix Figure 4 This is a schematic diagram showing the shape of the airbag in some embodiments of the present invention, which is a retractable shape (corresponding to the cruise retracted state); Appendix Figure 5 The following is a diagram defining the geometric parameters of the skid-type airbag landing gear system in some embodiments of the present invention, wherein (a) is a schematic diagram of the skid-type multi-chamber airbag assembly mechanism from the side view of the fuselage; (b) is a schematic diagram of the skid-type multi-chamber airbag assembly mechanism from the front and rear view of the fuselage; and (c) is a schematic diagram of a single skid-type multi-chamber airbag assembly mechanism. Appendix Figure 6 This is a schematic diagram of the gas path in some embodiments of the present invention; Appendix Figure 7 This is a block diagram of the cascaded draft control in some embodiments of the present invention; Appendix Figure 8 The following are schematic diagrams of the hydrofoil gliding state shaping mechanism in some embodiments of the present invention, wherein (a) is a schematic diagram of the skid-type multi-chamber airbag assembly mechanism when fully inflated; and (b) is a schematic diagram of the skid-type multi-chamber airbag assembly mechanism when partially deflated, wherein S is the maximum thickness of the airfoil cross section.

[0022] The components include: 1. Airframe; 2. Lift rotor assembly; 3. Tail thrust unit; 4. Skid-type airbag landing gear system; 41. Skid-type multi-chamber airbag assembly; 41a. First air chamber; 41b. Second air chamber; 41c. Third air chamber; 41d. Fourth air chamber; 42. Shaping tensioning component; 43. Inflation / depression actuator; 43a. Miniature air pump; 43b. Solenoid valve assembly; 43c. One-way valve; 43d. Pressure stabilizing chamber; 43e. High-pressure gas cylinder; 43f. Electrically controlled quick-opening valve; 44. Sensing unit; 44a. Absolute pressure sensor; 44b. Differential pressure sensor; 44c. Water contact electrode; 5. Airbag management controller; 6. Flight controller; 7. Wing; 8. Landing strut; 9. Skid beam; 10. Water surface; 11. Flat bottom taxiway; 12. Top cable; 13. Bottom cable. Detailed Implementation

[0023] 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.

[0024] The purpose of this invention is to provide an airbag-type amphibious take-off and landing system and method for unmanned aerial vehicles (UAVs), enabling the UAV to actively adjust the gas volume in each chamber according to load changes and sea state disturbances, thereby dynamically switching between floating, gliding, full gliding and cruise retraction states.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] refer to Figures 1-8The UAV airbag-type amphibious takeoff and landing system disclosed in this embodiment of the invention includes at least a UAV body 1. A power assembly and a flight controller 6 are mounted on the body 1. The power assembly includes a lifting rotor assembly 2, a tail thrust unit 3, and a wing 7 mounted on the body 1. A skid-type airbag landing gear system 4 is also mounted below the body 1. An airbag management controller 5 is mounted on the skid-type airbag landing gear system 4 or the body 1. The skid-type airbag landing gear system 4 includes a skid-type multi-chamber airbag assembly 41. A shaping tensioning member 42 is mounted on the skid-type multi-chamber airbag assembly 41. An inflation / deflation execution unit 43 and a sensing unit 44 are disposed inside the skid-type multi-chamber airbag assembly 41. The skid-type multi-chamber airbag assembly 41 includes at least two independent air chambers. The sensing unit 44 is used to acquire pressure information and water contact status information in each air chamber. The airbag management controller 5 is communicatively connected to the inflation / deflation execution unit 43, the sensing unit 44, and the flight controller 6. Based on the set target draft and pressure information within the air chambers, the gas regulation amount in each air chamber is determined, and then the gas volume in each air chamber is adjusted in a closed loop. This allows the skid-type airbag landing gear system 4 to control the transition between floating, gliding, hydrofoil gliding, and cruise retracted states. The airbag management controller 5 integrates the sensing unit 44 and the inflation / deflation execution unit 43, and, combined with the shaping tensioning member 42, precisely maintains the skid-shaped hydrodynamic shape, achieving closed-loop control of the pressure in each independent air chamber. This enables the UAV to actively adjust the gas volume in each chamber according to load changes and sea state disturbances, thereby dynamically transitioning between floating, gliding, full gliding, and cruise retracted states. This not only significantly suppresses pitch and roll in waves, but also reduces flight aerodynamic drag during the cruise phase by retracting the airbags. At the same time, relying on multi-chamber physical isolation redundancy and active asymmetric inflation mechanism, it has emergency self-righting capability, thus significantly improving the UAV's survivability, mission adaptability, and range endurance in complex environments such as deep seas and islands.

[0027] It should be noted that the air chamber is the airbag, which is a flexible structure. The airbag management controller 5 communicates with the flight controller 6 through a serial bus, receives modal commands and feeds back the airbag status; the flight controller 6 outputs thrust and attitude commands to the lift rotor assembly 2 and the tail thrust unit 3.

[0028] In one implementation, the sensing unit 44 includes pressure sensors and water contact detection elements disposed in each air cavity, used to acquire pressure information and water contact status information of each air cavity. The pressure sensors include an absolute pressure sensor 44a disposed at the bottom of each air cavity and a differential pressure sensor 44b disposed between the top and bottom of the same air cavity. The water contact detection element is a water contact electrode 44c. By deploying the absolute pressure sensor 44a at the bottom of the air cavity to sense the absolute difference between the external water pressure and atmospheric pressure, and combining it with the differential pressure sensor 44b between the top and bottom of the same air cavity to monitor the pressure difference inside and outside the bladder in real time, an environmental... The dual-parameter fusion sensing architecture of water pressure reference and bladder working pressure difference: The absolute pressure sensor 44a accurately obtains the hydrostatic pressure information of the current water depth of the air chamber, thereby calculating the real-time draft and submersion boundary, and providing the air bladder management controller 5 with feedback on the actual drainage volume in the floating state; the differential pressure sensor 44b directly reflects the effective pressure difference borne by the bladder membrane, that is, the working gauge pressure, the value of which is directly related to the bladder inflation volume, elastic deformation and external water pressure disturbance. The combination of the two enables the controller to accurately distinguish the draft change caused by load change and the dynamic pressure pulsation caused by wave impact, and avoids erroneous adjustment.

[0029] refer to Figures 1-3In one embodiment, two skid-type multi-chamber airbag assemblies 41 are provided and symmetrically spaced along the wingspan direction of the fuselage 1. When inflated, the skid-type multi-chamber airbag assemblies 41 take on a skid shape under the limiting action of the shaping tensioner 42, i.e., the bottom is a flat-bottomed sliding surface 11. The flat-bottomed sliding surface 11 is connected to sidewalls on both sides along the wingspan direction, and the sidewalls extend away from the central axis and upward of the fuselage 1. The flat-bottomed sliding surface 11 is connected to an upward-curved section at the head of the fuselage 1 and to a smooth section at the tail of the fuselage 1. The smooth section, the upward-curved section, the sidewalls, and the flat-bottomed sliding surface 11 together constitute the skid-type multi-chamber airbag assembly 41. The left and right symmetrical double skid-type multi-chamber airbag assemblies 41 are arranged at intervals along the wingspan direction. Under the limiting action of the shaping tensioner 42, a complete skid-shaped hydrodynamic configuration with a flat-bottomed sliding surface 11, sidewalls, an upward-curved section at the bow, and a smooth section at the tail is formed. The left and right symmetrical arrangement not only provides the fuselage 1 with a wide... The wide lateral stability support span allows for active control of the roll angle by adjusting the pressure difference between the two airbags. Combined with the flat-bottomed taxiing surface 11 and the bottom lift angle design of the sidewalls, water flow is smoothly guided laterally during taxiing to reduce the risk of splash intrusion into the rotor. The upward-curved bow section ensures sufficient anti-head-down capability when taxiing in waves, while the smooth tail section ensures clean separation of airflow / water flow at the tail, effectively reducing the peak drag during the peak crossing phase. This not only ensures geometric certainty during independent pressurization of multiple chambers, making the hydrodynamic model highly predictable, but also achieves dynamic conversion between the large displacement volume in the floating state and the small wet area in the full taxiing state. Thus, the same landing gear structure can simultaneously meet the requirements of multiple scenarios such as floating stability, high-speed taxiing maneuverability, vertical take-off and landing on land / islands, and cruise retraction drag reduction, significantly improving the take-off and landing safety and mission adaptability of UAVs in complex sea conditions and multi-platform conditions.

[0030] It should be noted that the bottom rise angle β between the sidewall and the vertical plane is 10°~25°, and the bow rise angle θ of the bow rise section is 20°~35°.

[0031] refer to Figures 5-6In one embodiment, the skid-type multi-chamber airbag assembly 41 includes two air chambers arranged along the length of the body 1. The two skid-type multi-chamber airbag assemblies 41 together include four air chambers: the first air chamber 41a, the second air chamber 41b, the third air chamber 41c, and the fourth air chamber 41d. The gas volume in each chamber is independently controlled. When the airbag is fully inflated, it is skid-shaped. The flat-bottomed sliding surface 11 and the sidewalls are inclined outward from the vertical to form a bottom rise angle, and the upward-curved section at the bow forms a bow rise angle. By dividing the left and right skid-type multi-chamber airbag assemblies 41 into two independent air chambers along the length of the body 1, a total of four independently controllable air chambers (the first to fourth air chambers 41d) are formed. Combined with the limiting constraints of the shaping tensioner 42, the UAV has active attitude control capabilities in both the vertical and longitudinal planes: In the longitudinal direction, the pitch angle during gliding can be dynamically controlled by independently adjusting the pressure difference between the front chamber (first air chamber 41a, third air chamber 41c) and the rear chamber (second air chamber 41b, fourth air chamber 41d), thereby actively matching the optimal water contact length at different speed stages (such as peak crossing, full gliding) to reduce gliding resistance and avoid bow submersion; In the lateral direction, the pressure difference between the corresponding air chambers on the left and right sides can be independently adjusted to counteract the lateral tilt moment caused by waves in real time, compensating for the insufficient anti-capsulation capability caused by the small initial stability height design.

[0032] refer to Figure 8As a preferred embodiment, the shaping tensioning element 42 includes tensioning cables, namely top cable 12 and bottom cable 13, threaded through the top and bottom of the multi-chamber airbag assembly. These tensioning cables extend within the skid-type multi-chamber airbag assembly 41 along directions parallel to and perpendicular to the wingspan of the fuselage 1, respectively. By threading tensioning cables extending bidirectionally along the wingspan and length of the fuselage 1 through the top and bottom of the skid-type multi-chamber airbag assembly 41, a three-dimensional stress-bearing skeleton is formed inside the airbag. A rigid constraint boundary is established between the flexible airbag body and the independent pressure control of the multiple chambers. This tensioning cable layout ensures that the top and bottom fibers bear bidirectional tensile tension during airbag inflation, effectively constraining excessive radial expansion of the airbag body. This precisely limits the spanwise and longitudinal curvature of the flat-bottomed sliding surface 11, ensuring that the bow upturn angle, tail smooth transition, and sidewall heel rise angle maintain their design expectations under different airbag pressure combinations. This solves the problem of pressure fluctuations or localized loads affecting purely flexible airbags. The inherent problems of shape distortion and hydrodynamic model mismatch caused by loads are addressed. Simultaneously, the bidirectional tension cable evenly transmits the membrane stress generated by the internal pressure of the airbag, as well as external loads such as impact loads during water gliding and bow slamming forces, along the fiber direction to the mounting interface of the fuselage 1. This avoids stress concentration at airbag corners or heat-sealed seams, significantly improving the airbag's fatigue tear resistance and structural durability under repeated inflation / deflation pressure and rough ground takeoff and landing conditions. Furthermore, as an internal constraint element, the tension cable achieves shape preservation without an external rigid frame, reducing system weight and ensuring that the airbag folds and adheres to the fuselage belly in an orderly manner along the tension cable direction during cruise retraction. This provides a definite deformation path for low-drag cruise retraction, achieving synergistic gains in ensuring hydrodynamic shape certainty under all operating conditions, improving structural fatigue life, and reducing system weight. This strongly supports the engineering reliability and long-life requirements of UAVs in frequent water surface takeoffs and landings and multi-platform switching missions.

[0033] It should be noted that the length of the tension cable at the top of the multi-chamber airbag assembly is greater than the length of the tension cable at the bottom of the multi-chamber airbag assembly. The length of the tension cable is determined according to the path of the inner surface of the fully inflated skid-type multi-chamber airbag assembly 41. When the skid-type multi-chamber airbag assembly 41 is partially deflated, the tension cable limits the longitudinal chord length of the entire skid-type multi-chamber airbag assembly 41 and restricts its vertical collapse. Due to the length difference between the top and bottom tension cables, the upper surface of the airbag bends downward under water pressure, forming an airfoil section with an angle of attack to generate hydrodynamic lift in hydrofoil gliding mode. When fully inflated, the bottom and top tension cables are simultaneously taut to ensure skid shape accuracy and prevent over-inflation deformation. Tension cables are also distributed along the wingspan direction of the fuselage 1 to maintain the shape in the thickness and spanwise directions.

[0034] refer to Figure 6As one implementation method, the inflation / deflation execution unit 43 includes a miniature air pump 43a, a solenoid valve group 43b connected to the miniature air pump 43a, and a pipeline for connecting the miniature air pump 43a and the solenoid valve group 43b. The solenoid valve group 43b is connected to the air chamber and the miniature air pump 43a through the pipeline. With the simplest hardware architecture, it realizes differentiated pressure regulation of four independent air chambers, which meets the stringent requirements of air pressure regulation speed and accuracy for dynamic working conditions such as draft fine adjustment in floating state, rapid response of pitch angle in gliding state, and active suppression of roll.

[0035] refer to Figure 6 As one implementation method, the inflation / deflation execution unit 43 also includes a one-way valve 43c, a pressure regulating chamber 43d, and an emergency air source. The one-way valve 43c and the pressure regulating chamber 43d are located between the miniature air pump 43a and the solenoid valve group 43b. The emergency air source is connected to the air chamber through the miniature air pump 43a. The emergency air source includes a high-pressure gas cylinder 43e and an electrically controlled quick-opening valve 43f. The high-pressure gas cylinder 43e is connected to each air chamber through the electrically controlled quick-opening valve 43f. The airbag management controller 5 detects a preset abnormal flight state. The electronically controlled quick-opening valve 43f is opened to fully inflate the skid-type multi-chamber airbag assembly 41 within a preset time to provide emergency buoyancy. The one-way valve 43c ensures that high-pressure gas cannot flow back in reverse when the micro air pump 43a stops or the pipeline leaks, maintaining the reference pressure in each air chamber and the pressure stabilizing chamber 43d. This avoids cross-flow of gas between adjacent air chambers or pressure fluctuations caused by pressure drop when the solenoid valve group 43b switches, and significantly improves the closed-loop regulation accuracy and response consistency of the airbag management controller 5 for the gas volume of each chamber.

[0036] refer to Figures 2-4As one implementation, the skid-type airbag landing gear system 4 also includes a landing strut 8 disposed between the skid-type multi-chamber airbag assembly 41 and the fuselage 1. A skid beam 9 extending along the length of the fuselage 1 is disposed between the landing strut 8 and the multi-chamber airbag assembly. The skid beam 9 is connected to the bottom surface of the skid-type multi-chamber airbag assembly 41, so that when the skid-type multi-chamber airbag assembly 41 is fully deflated, it covers the skid beam 9 and the lower section of the landing strut 8, forming a low-frontal area converged and rectified shape. The landing strut 8, as a vertical load-bearing component, directly transmits the water impact, taxiing hydrodynamic lift, and land takeoff and landing load to the main structure of the fuselage 1, while the skid beam 9 extending along the length of the fuselage 1 is fixedly connected to the bottom surface of the airbag. When the airbag is inflated, it acts as a longitudinal skeleton to constrain the longitudinal curvature of the flat-bottomed sliding surface 11, ensuring that the geometric accuracy of the bow upturn and the tail smooth section is not affected by the pressure difference of the airbag segments. On the other hand, when fully deflated and retracted, the flexible airbag is orderly attached and folded along the surface of the skid beam 9 and the lower section of the landing strut 8 under the synergistic traction of the shaping tensioner 42 and the bidirectional tension cable, forming a low frontal area fairing shape that fits tightly against the fuselage. This not only eliminates the additional aerodynamic drag caused by the disorderly drifting or bulging of the traditional soft airbag after deflation, but also gives the landing system a deterministic aerodynamic shape in the cruise retracted state, which smoothly transitions with the fuselage installation area, thereby minimizing the adverse effects of the water surface landing device on the cruise lift-to-drag ratio.

[0037] As one implementation, the skid-type airbag landing gear system 4 is also used for ground take-off and landing: during ground take-off and landing, the skid-type multi-chamber airbag assembly 41 maintains a low-pressure state, adapts to uneven ground and buffers landing impact through the elastic deformation of the airbag body, so that the ground pressure is lower than the preset ground allowable pressure.

[0038] It should be noted that the skid-type multi-chamber airbag assembly 41 is connected to the body 1 via the landing strut 8. The upper end of the landing strut 8 is connected to the load-bearing hard point of the body 1, and the lower end is connected to the longitudinally arranged skid beam 9. The bottom surface of the skid-type multi-chamber airbag assembly 41 is mechanically connected to the skid beam 9 via a pressure strip. The connection area is reinforced with a patch, and the end of the shaping tensioning member 42 is anchored to the skid beam 9 or the structural hard point of the body 1.

[0039] This invention also discloses a method for unmanned aerial vehicle (UAV) airbag-type amphibious takeoff and landing, which utilizes the aforementioned UAV airbag-type amphibious takeoff and landing system and includes the following steps: Step 1: Operating mode recognition and target draft setting The flight controller 6 determines the current operating mode based on the mission phase (pre-takeoff standby, water surface taxiing, cruise flight, landing preparation) and the external environment (calm water / waves, land / water 10); Airbag management controller 5 calculates the target draft based on the selected mode: Floating state on water surface: The skid-type multi-chamber airbag assembly 41 is fully inflated and has no power drive. Based on the current load weight and design wave height, the target draft is calculated according to the static buoyancy balance equation (as shown in formula 4-6 below), while simultaneously meeting the initial stability requirements. Water gliding state: The skid-type multi-chamber airbag assembly 41 is fully inflated and powered, and the initial target draft value is set to be consistent with the target draft value in the water floating state. Hydrofoil skidding mode: The skid-type multi-chamber airbag assembly 41 is in a partially deflated state, powered by a motor. The target draft is determined by the hydrofoil immersion margin, using the following formula: In the formula, (0.3~0.5)· The critical immersion depth for airflow is denoted as , and the immersion depth margin is denoted as , which is determined according to the design wave height (taken as 0.1~0.2 times the chord length). Here, the chord length is the length of the hydrofoil formed by the skid-type multi-chamber airbag assembly 41. Cruise retracted state: The target draft is zero (the airbag is fully deflated and attached), and the pump draws air to create a slight negative pressure so that the airbag is attached to the skid beam to prevent the airbag from inflating.

[0040] Step 2: Multi-chamber closed-loop adjustment achieves precise following of actual draft. The sensing unit 44 collects the absolute pressure and water contact status at the bottom of each air chamber in real time, and calculates the current actual draft and pitch angle. The controller compares the deviation between the actual draft and the target draft, and calculates the required inflation or deflation volume for each independent air chamber (first to fourth air chambers 41d) according to a predetermined allocation strategy, based on the current pressure and volume relationship of each chamber. The closed-loop regulation adopts a cascade structure: the deviation between the actual draft and the target draft is used by a PID controller and superimposed with the air chamber pressure feedforward value calculated offline based on the buoyancy balance relationship to generate an air chamber pressure reference value; the deviation between the air chamber pressure reference value and the actual pressure value in the air chamber is used by a pressure loop PID controller to generate the duty cycle of the micro air pump 43a and the opening command of the solenoid valve group 43b. The actual draft is determined by the pressure information and water contact status information of each air chamber (the water contact detection element determines whether each air chamber is actually submerged in water. The pressure data of the air chamber is only valid when the water contact signal is true; the pressure measurement data of the air chambers away from the water (such as the bow section during high-speed taxiing) is automatically shielded to prevent atmospheric pressure from being mistakenly judged as zero draft. Then, the local draft is calculated by back-calculating the pressure information: for the effective air chamber, the absolute pressure measured by the absolute pressure sensor at its bottom is subtracted from the current atmospheric pressure, and then divided by the product of water density and gravitational acceleration to obtain the actual immersion depth at the location of the chamber). ,in Atmospheric pressure Let g be the density of water, P be the gravitational acceleration, and P be the hydrostatic pressure outside the bottom of the air chamber. The local immersion depths of all effective air chambers are weighted and averaged according to the proportion of the bottom area of ​​each chamber to obtain the average actual draft of the entire unit. Simultaneously, comparing the draft difference between the front and rear chambers allows for the calculation of the pitch angle, and comparing the draft difference between the left and right chambers allows for the calculation of the roll angle, providing complete attitude feedback for closed-loop control. The differential pressure sensor is used to eliminate pressure interference caused by the elastic deformation of the bladder, ensuring the accuracy of the back-calculation.

[0041] By selecting the corresponding air chamber through the solenoid valve group 43b, the micro air pump 43a is started to replenish air or the exhaust valve is opened to release gas, so as to achieve independent adjustment of the pressure of each chamber; during the adjustment process, the pressure stabilizing chamber 43d buffers the air supply pulsation, and the one-way valve 43c prevents backflow and cross-flow of air.

[0042] Step 3: Active switching of draft to adapt to gliding speed During water gliding, the target draft is switched between a fully inflated water gliding state and a partially deflated hydrofoil gliding state depending on the gliding speed. State transitions are triggered by both external conditions and control objectives, including: Firstly, the taxiing speed conditions: when the taxiing speed is greater than the mode switching threshold and there is no intention to take off, the taxiing mode is switched from water surface taxiing mode to hydrofoil taxiing mode; when the taxiing speed is lower than the critical wing speed, the taxiing mode is switched to fully inflated skid water surface taxiing mode.

[0043] Secondly, sea conditions: when the actual wave height does not exceed 0.5m of the design wave height, water taxiing and hydrofoil taxiing can be used; when the wave height exceeds 0.5m, switch to vertical take-off and landing mode. Rotary hovering take-off and landing is not restricted by sea conditions, and water taxiing is suitable for sea condition ranges determined according to the propeller disk clearance conditions. As for the wave height identification method, it can be provided by an airborne vision system, laser sensor, or ground sea condition monitoring system, and this patent does not impose any restrictions.

[0044] Third, take-off and landing conditions: When landing on the water surface, the ground end needs to give a control signal, and the inflation / deflation execution unit 43 will pre-inflate the airbag to a floating state on the water surface during the descent phase. After landing, it will maintain floating by static buoyancy. When long-distance cruise is required, it will enter the cruise retraction state after leaving the water. The airbag will be fully deflated and covered by the skid beam 9 and the lower section of the landing strut 8 to rectify the aerodynamic drag of cruise.

[0045] Fourth, abnormal conditions - when a preset abnormal flight condition is detected, the airbag management controller 5 opens the electronically controlled quick-opening valve 43f, and the high-pressure gas cylinder 43e quickly inflates each air chamber to provide emergency buoyancy.

[0046] The following explanation uses a 15kg-class compound-wing vertical takeoff and landing fixed-wing UAV as an example: Two skid-type multi-chamber airbag assemblies 41 are arranged symmetrically on both sides, with a dual-bag track gauge. Based on the rotor arrangement constraints and initial stability requirements, the larger value should be taken according to equation (1). Figure 5 (b) shows the double-bag gauge. 8 effective height of lifting struts With the number of pillars Definition: In the formula For initial stability height, The surface area of ​​the waterline of a single bladder. The total drainage volume is 0.090 m³ in this embodiment. 2 14.6L. , These are the heights of the center of buoyancy and the center of gravity, respectively. The value is taken as the design requirement value, according to the conventional design practice for the stability of small floating bodies. The gauge is 0.27m. In this embodiment, the gauge of the double-bag track is 0.55m.

[0047] In this embodiment, each feature dimension is determined by the UAV's main parameters, which are: maximum takeoff weight. ,span ,captain gliding design speed With design wave height The specific parameters for this embodiment are: maximum takeoff weight 15kg, wingspan 2.83m, length 1.26m, taxiing design speed 5.0m / s, and design wave height 0.5m.

[0048] The first step is to determine the dimensions of the taxiing surface, which are determined by the required taxiing lift. The wetted taxiing area is then designed. It is an important parameter for the design of the sliding surface dimensions, which is determined by equation (2). and Confirmed, among which The lift coefficient of the skid surface is 0.16.

[0049] gliding surface length With effective gliding width Determine according to formula (3) The wet aspect ratio for gliding is (4~6). Glide surface width That is, 0.12m.

[0050] Secondly, the determination of the draft when floating on the water surface. The cross-sectional area of ​​the immersion point Volume of water immersed in a single capsule Equations (4) and (5) are respectively.

[0051] Bow upturn correction factor Take a value of 0.8 to 0.95.

[0052] When fully filled and floating on the surface, the submerged volume of a single bladder is equal to its displaced volume; the draft in the floating state can be obtained by solving this equation. That is, formula (6) In this embodiment Take 0.09m.

[0053] sac height Determine according to formula (7): In the formula The freeboard factor is taken as 0.3~0.5. In this embodiment, the bladder height... It is 0.18m For actual mold manufacturing, the total volume of the double-cavity mold cavity and the volume of the single-cavity mold cavity are determined according to formula (8): In the formula To reserve the buoyancy coefficient, a value of 2.0 to 2.5 is used. The density is that of water. This example is... .

[0054] The basal rise angle and the bow upturn angle are determined according to the design wave height: The upper and lower limits of the basal rise angle and the bow upturn angle are 10°~25° and 20°~35°, respectively. This embodiment... .

[0055] The capsule is made of TPU-coated fabric through high-frequency thermal bonding, and the capsule membrane thickness is... The strength relationship with the working gauge pressure is determined according to formula (10), the working gauge pressure is 20 kPa, the ultimate strength of the membrane is taken as 30 MPa, and the safety factor is... Not less than 5 In the formula ≈ / 2. In addition to being subject to the working pressure requirements, the membrane thickness is also affected by environmental aging, sea salt corrosion, ground wear, etc. Therefore, in this embodiment, the membrane thickness is 0.50mm, and the bottom of the membrane is further thickened and reinforced.

[0056] In summary, the main characteristic parameters of the airbag landing gear system in this embodiment include the dual-bag gauge. =0.55m; single-bucket gliding surface length L=0.68m, effective gliding width b=0.12m; heave angle β=15°, bow upturn angle θ=22.5°; draft in fully filled floating state h0=0.09m, bucket height =0.18m; membrane thickness =0.50mm; In the water-surface gliding phase, water-surface gliding is used for water-surface maneuvering, and lift-off is achieved by the vertical thrust of the lift rotor assembly 2. The maximum drag during the gliding phase occurs at the peak speed. Place In this embodiment, the peak velocity is 2.0 m / s. Tail thrust static force. It must be greater than this peak resistance: In the formula, The steep inclination angle of the peak. The sliding wet area (Equation (2)) The coefficient of friction is 0.005. When gliding on the water surface, the static thrust must be greater than 14N.

[0057] The shaping and tensioning component 42 is mainly based on molding and supplemented by tension cable limiting: the bladder is formed by molding and heat bonding of a TPU coated fabric membrane according to a skid-shaped cross section. The skid-shaped cross section is the inherent shape of the bladder. The full-inflation skid shape (floating on the water surface and gliding on the water surface) and the hydrofoil gliding state share the same cross section. The conversion between the states is achieved by adjusting the amount of gas inside the bladder. The tension cable is connected to the inner surface of the bladder membrane by multiple points along its length. The tension cable part near the structural hard point of the skid beam 9 or the body 1 is fixed to the structural hard point of the skid beam 9 or the body 1 and is fixed in length according to the path of the inner surface of the bladder in the full-inflation skid shape state.

[0058] After partial deflation and entry into the hydrofoil's gliding state, the internal pressure of the capsule decreases, and the membrane surface tends to relax. However, the tension cable has a certain stiffness, which can limit the longitudinal chord length of the capsule to a predetermined value and restrict its collapse in the thickness direction. The hydrofoil's gliding state transition is as follows: Figure 8 As shown, due to the difference in length between the tension cables on the upper and lower surfaces, under the same water pressure, the tension cable on the upper surface of the capsule undergoes greater deformation displacement and bends downward under the action of water pressure. The lower edge cable is a straight line with a fixed length along the bottom of the capsule. The length of this path remains unchanged in both states, and the deformation displacement of the cable caused by water pressure is relatively small, ultimately forming a certain airfoil section and a certain angle of attack.

[0059] Once in hydrofoil gliding mode, the hydrofoil must bear the load-bearing capacity of the hydrofoil. The total weight is 0.7 to 0.9 times the weight of the aircraft, determined by the hydrofoil criterion. Critical wing speed: In the formula, The effective wing area is determined by the lateral spacing between the two bladders (Equation (1)) and the chord length. Sure The lift coefficient, taken as 0.3~0.4, corresponds to the effective angle of attack. 4°~6°. The critical wing speed in this embodiment is 2.2 m / s. Mode switching threshold. according to The speed was selected from the vicinity; in this embodiment, it was 2.5 m / s.

[0060] The target draft in the hydrofoil's gliding state is determined by the immersion depth constraint: when the immersion depth is less than the critical immersion depth for ventilation, air is drawn into the wing surface, leading to lift decay. The target draft is determined according to formula (13). In the formula, (0.3~0.5)· This is the critical immersion depth for wing surface ventilation. The immersion depth margin is determined based on the design wave height (0.1~0.2 times the chord length), and in this embodiment, it is 0.04m. Target draft. It is 0.24m.

[0061] The connection between the capsule and body 1 adopts a rigid-flexible hybrid structure: such as Figure 2 As shown, the upper end of the landing strut 8 connects to the load-bearing hard point below the fuselage 1, and the lower end converges at the longitudinally arranged skid beam 9; the bottom surface of the capsule is mechanically connected to the skid beam 9 by pressure strips and bolts or straps, and the connection area is locally reinforced with patches. The effective height of the landing strut 8 is... The clearance condition of the tail thruster disk is determined according to formula (14): In the formula This is the minimum distance from the ground to the propeller tip (0.10~0.15 m). For splash margin (approximately 0.10 m), The net height from the bottom surface of fuselage 1 to the lowest point of the tail thruster disk; Additionally, it is constrained by the minimum structural height. In this embodiment, the final height is 0.32m.

[0062] For the realization of airbag status control, there is a certain mathematical relationship between draft and the amount of gas inside the airbag.

[0063] In other words, inflation reduces the draft, while deflation increases the draft. The change in gas volume over time is determined by the inflation and deflation flow rates, which are modeled as the outflow from the throttling orifice. No. The gas volume in the cavity satisfies: In the formula This is the molar mass of air.

[0064] Therefore, the control method in this embodiment mainly involves setting a target draft based on the operating mode, and then... Figure 7 The cascade closed-loop regulation control is used. Specifically, in the hydrofoil gliding state, the airbag management controller 5 uses the draft depth as the controlled variable. When entering the hydrofoil gliding state, the target draft depth is set to 0.24m according to formula (13). This target value is determined by... Figure 7 The cascaded closed-loop tracking shown in the figure is as follows: The outer control loop is the draft depth loop. The difference between the target draft depth and the soft measurement value of the draft depth (Equation (18)) is generated by the PID controller and superimposed with the feedforward lookup table entry calculated offline according to Equation (15) to generate the air chamber pressure reference value. The inner control loop is the pressure loop. The pressure reference value is tracked by the duty cycle of the micro air pump 43a and the opening degree of the solenoid valve. The skid-type multi-chamber airbag assembly 41 is deflated at the rate of the schedule table, so that the airbag body bends out of the airfoil section under the action of water pressure and is limited by the shaping tensioning member 42 to form a hydrofoil. The deflation rate is constrained by the schedule table to avoid sudden drop in buoyancy and instability of the airbag body. During the gliding process, the draft depth is automatically corrected by the closed loop according to the instantaneous disturbance of the waves, so that the immersion depth of the airfoil is always greater than the critical immersion depth of ventilation and the lift does not decline due to the air intake of the airfoil.

[0065] In practice, the draft depth is directly calculated using the 44a absolute pressure sensor for soft measurement. in Atmospheric pressure Let g be the density of water, g be the acceleration due to gravity, and P be the hydrostatic pressure outside the bottom of the air chamber. The differential pressure sensor 44b detects the pressure difference between the top and bottom of the chamber to determine whether water has entered the chamber and the level of the water. The water-contact electrode 44c provides a water-contact trigger signal. The absolute pressure, differential pressure, and water-contact information are filtered by complementary means to obtain the draft and water-contact status, which constitute the measurement input for the above closed-loop control.

[0066] The pump flow rate of the micro air pump 43a is selected according to the inflation time requirement of formula (19), and the gas storage capacity of the high-pressure gas cylinder 43e is calibrated according to the full filling requirement of formula (19). It forms an emergency branch through the electrically controlled quick-opening valve 43f, which directly connects to each air chamber. After opening, it completes rapid inflation. Inflation is usually completed during the descent phase until it floats on the water surface. The preparation time before landing does not increase.

[0067] In the cruise retracted state, the capsule is fully deflated, and a pump draws air in to create a slight negative pressure inside. Under the suction of this negative pressure and the contraction of the shaping tensioner 42, the capsule collapses and covers the lower section of the skid beam 9 and landing strut 8, forming a low-frontal area retracted and rectified configuration to reduce cruise aerodynamic drag. If necessary, the landing gear can be designed as a retractable structure, allowing the capsule to be attached to the fuselage after retraction.

[0068] During ground takeoffs and landings, the skid-type multi-chamber airbag assembly 41 maintains a low-pressure state, utilizing the large elastic deformation of the airbag to adapt to uneven ground and buffer the landing impact. Water taxiing is suitable for sea states determined by the clearance conditions; in higher sea states, only vertical takeoff and landing mode is used, while rotor hovering takeoffs and landings are not subject to this restriction. When landing on a floating platform at sea, the platform approaches at the relative vertical speed of the UAV, and after landing, the airbags buffer and absorb the platform's rise and fall.

[0069] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A UAV airbag-type amphibious takeoff and landing system, comprising a fuselage (1), a power assembly and a flight controller (6) mounted on the fuselage (1), characterized in that, It also includes a skid-type airbag landing gear system (4) and an airbag management controller (5) located below the fuselage (1). The skid-type airbag landing gear system (4) includes a skid-type multi-chamber airbag assembly (41), a shape-fixing tensioner (42) located on the skid-type multi-chamber airbag assembly (41) for maintaining the shape of the skid-type multi-chamber airbag assembly (41), and an inflation / deflation actuation unit (43) and a sensing unit (44) located inside the skid-type multi-chamber airbag assembly (41). The skid-type multi-chamber airbag assembly (41) includes at least two independent airbags. The sensing unit (44) is used to acquire the pressure information and water contact status information of each air chamber. The airbag management controller (5) is communicatively connected to the inflation / deflation execution unit (43), the sensing unit (44) and the flight controller (6). The airbag management controller (5) determines the gas regulation amount of each air chamber according to the target draft and the pressure information, and adjusts the gas amount of each air chamber in a closed loop, so that the skid-type airbag landing gear system (4) can be controlled to switch between the floating state, the gliding state, the hydrofoil gliding state and the cruise retracted state.

2. The UAV airbag-type amphibious takeoff and landing system according to claim 1, characterized in that, At least two skid-type multi-chamber airbag assemblies (41) are provided and are spaced apart along the wingspan direction of the fuselage (1). When fully inflated, the skid-type multi-chamber airbag assembly (41) is skid-shaped under the limiting action of the shaping tensioner (42), forming a flat-bottomed sliding surface (11), a side wall connected to the flat-bottomed sliding surface (11) and extending toward and above the direction away from the central axis of the fuselage (1), and a bow upturned section connected to the flat-bottomed sliding surface (11).

3. The UAV airbag-type amphibious takeoff and landing system according to claim 2, characterized in that, The skid-type multi-chamber airbag assembly (41) includes at least two air chambers arranged along the length of the body (1).

4. The UAV airbag-type amphibious takeoff and landing system according to claim 1, characterized in that, The shaping tensioner (42) includes tensioning cables passing through the top and bottom of the multi-chamber airbag assembly, and the tensioning cables extend inside the skid-type multi-chamber airbag assembly (41) along the wingspan direction parallel to the fuselage (1) and perpendicular to the wingspan direction of the fuselage (1), respectively.

5. The UAV airbag-type amphibious takeoff and landing system according to claim 1, characterized in that, The inflation / deflation unit (43) includes a micro air pump (43a), a solenoid valve assembly (43b) connected to the micro air pump (43a), and a pipeline for connecting the micro air pump (43a) and the solenoid valve assembly (43b). The solenoid valve assembly (43b) is connected to the air chamber and the micro air pump (43a) through the pipeline.

6. The UAV airbag-type amphibious takeoff and landing system according to claim 1, characterized in that, The skid-type airbag landing gear system (4) also includes a landing strut (8) disposed between the skid-type multi-chamber airbag assembly (41) and the fuselage (1). A skid beam (9) extending along the length of the fuselage (1) is disposed between the landing strut (8) and the multi-chamber airbag assembly. The skid beam (9) is connected to the bottom surface of the skid-type multi-chamber airbag assembly (41), so that the skid-type multi-chamber airbag assembly (41) in the fully deflated state covers the lower section of the skid beam (9) and the landing strut (8), forming a low frontal area converged and rectified shape.

7. A method for unmanned aerial vehicle (UAV) airbag-type amphibious takeoff and landing, applied to the UAV airbag-type amphibious takeoff and landing system according to any one of claims 1 to 6, characterized in that, Includes the following steps: The target draft is set according to the working mode, which includes floating on the water surface, gliding on the water surface, gliding with hydrofoil, and cruising and retracting. The gas volume of each gas chamber is adjusted in a closed loop by the gas filling and emptying execution unit (43) so that the actual draft follows the target draft. During water gliding, the target draft is switched between a fully inflated water gliding state and a partially deflated hydrofoil gliding state according to the gliding speed.

8. The method for unmanned aerial vehicle (UAV) airbag-type amphibious takeoff and landing according to claim 7, characterized in that, The target draft of the hydrofoil in the gliding state is determined by the hydrofoil immersion margin.

9. The UAV airbag-type amphibious takeoff and landing method according to claim 7, characterized in that, The closed-loop regulation adopts a cascade structure: the deviation between the actual draft and the target draft is processed by a PID controller and superimposed with the air chamber pressure feedforward value calculated offline based on the buoyancy balance relationship to generate an air chamber pressure reference value. The pressure loop PID controller generates instructions based on the deviation between the reference pressure value of the air chamber and the actual pressure value inside the air chamber, and controls the air filling and emptying execution unit (43) to perform air filling and emptying operations on the air chamber.

10. The UAV airbag-type amphibious takeoff and landing method according to claim 7, characterized in that, The actual draft is determined by the pressure information and water contact status information of each air chamber.

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