Buoyancy-assisted rising hydrogen fuel cell unmanned aerial vehicle and use method thereof

Abstract

The invention relates to the technical field of unmanned aerial vehicles, provides a buoyancy-assisted hydrogen fuel cell unmanned aerial vehicle and a use method thereof, and provides a new gas configuration scheme in combination with operation characteristics of a hydrogen fuel cell system. Automatic inflation, automatic keeping and automatic exhaust of the air bag are achieved through linkage control of the three-position three-way valve and the air bag inhaul cable. Meanwhile, the lifting frame capable of ascending and descending and the storage box capable of being opened and closed are matched, the lifting frame is automatically unfolded and the storage box is automatically opened when the air bag is inflated, the lifting frame is automatically folded and the storage box is automatically closed when the air bag is recycled, and the automatic control device has the advantage that the air bag is automatically controlled to be unfolded and stored.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicles, in particular to a buoyancy auxiliary lifting hydrogen fuel cell unmanned aerial vehicle and a use method thereof. BACKGROUND

[0002] The hydrogen fuel cell unmanned aerial vehicle is an unmanned aerial vehicle taking hydrogen fuel cell as the core power source, generating electric energy through chemical reaction of hydrogen and oxygen, driving the motor to realize flight, and is an important technical direction in the field of new energy unmanned aerial vehicles.

[0003] Based on the principle of "buoyancy assistance", an auxiliary lifting air bag is installed on the unmanned aerial vehicle, the lifting force of the auxiliary lifting air bag is used to offset part of the weight of the unmanned aerial vehicle, so as to reduce the energy consumption of the power system, prolong the endurance time, and also strengthen the carrying capacity of the unmanned aerial vehicle. For example, the unmanned aerial vehicle with strong endurance disclosed by Chinese patent CN206606352U sets a bag-shaped object on the unmanned aerial vehicle, and fills the bag-shaped object with gas with density less than that of air, so as to help offset part of the gravity of the unmanned aerial vehicle, reduce energy consumption, and improve the endurance of the unmanned aerial vehicle. In the technical solution of the above patent, the air bag needs to be manually deployed and stored, which is complicated and affects the operation efficiency.

[0004] Therefore, how to realize the automatic deployment and storage of the auxiliary lifting air bag of the unmanned aerial vehicle has become a technical problem to be solved by the technical personnel in the field. SUMMARY

[0005] Therefore, the present application aims to provide a buoyancy auxiliary lifting hydrogen fuel cell unmanned aerial vehicle to automatically control the deployment and storage of the auxiliary lifting air bag.

[0006] Another object of the present application is to provide a use method of the above buoyancy auxiliary lifting hydrogen fuel cell unmanned aerial vehicle.

[0007] In order to achieve the above object, the present application provides a buoyancy auxiliary lifting hydrogen fuel cell unmanned aerial vehicle, comprising a rack, a rotor assembly, a fuel cell and a hydrogen bottle arranged on the rack, wherein the hydrogen bottle and the fuel cell are connected through a main pipeline; and an auxiliary lifting mechanism arranged on the rack.

[0008] The auxiliary lifting mechanism comprises:

[0009] A lifting frame is installed on the top surface of the rack, and the lifting frame has a deployed state of rising upward and a folded state of folding downward.

[0010] A storage box fixed to the top of the lifting frame, the storage box comprising a bottom plate and two half-box bodies hinged to both sides of the bottom plate, reset elastic members being arranged between the two half-box bodies and the bottom plate, after the removal of external force, the half-box bodies contact and cover the bottom plate under the action of the respective reset elastic members, box body cables being arranged between the two half-box bodies and the lifting frame, when the lifting frame is in an unfolded state, the half-box bodies are away from and expose the bottom plate under the tension of the respective box body cables;

[0011] An air bag placed on the bottom plate, the air bag being communicated with the main pipeline through a branch pipeline, a three-position three-way valve being arranged on the branch pipeline, a T port of the three-position three-way valve being communicated with the main pipeline, a plurality of air bag cables being arranged on the outer wall of the air bag along the circumference of the air bag, the upper ends of the plurality of air bag cables being gathered at the center of the top of the air bag, the lower end of each air bag cable being connected with a cable winding and unwinding mechanism after sliding through a through hole arranged in the outer wall of the air bag and finally passing through the bottom plate.

[0012] Preferably, a plurality of limiting members are fixedly arranged on the outer wall of the air bag along the extension direction of each air bag cable, and the air bag cable slides through the limiting members in sequence from top to bottom.

[0013] Preferably, an ejector is further arranged on the main pipeline, and the T port of the three-position three-way valve is communicated with the induced fluid inlet of the ejector.

[0014] Preferably, the lifting frame comprises a base, an arm and a driving mechanism.

[0015] The base is fixed to the top of the frame.

[0016] The arm comprises two pairs of arm rods arranged in upper and lower positions, each pair of arm rods being composed of two arm rods arranged in a cross shape and pivotally connected at the middle part.

[0017] The lower end of the upper arm rod is hingedly connected with the upper end of the corresponding lower arm rod.

[0018] The upper end of one of the upper arm rods is hingedly connected with the bottom plate, and the upper end of the other upper arm rod is slidingly connected with the bottom plate.

[0019] The lower end of one of the lower arm rods is hingedly connected with the base, and the lower end of the other lower arm rod is slidingly connected with the base.

[0020] The driving mechanism is connected with the lower arm rod slidingly connected with the base to drive the lower end of the arm rod to slide along the base.

[0021] Preferably, one end of the box body cable is fixedly connected with the outer wall of the half-box body, and the other end of the box body cable is fixedly connected with the pivot.

[0022] Preferably, the bottom plate and the base are both provided with sliding plates provided with strip-shaped sliding holes, and the arm rods corresponding to the sliding plates are all fixedly provided with sliding rods which are inserted into the strip-shaped sliding holes and slidingly matched with the strip-shaped sliding holes.

[0023] Preferably, the number of the supporting arms is two, the two supporting arms are arranged in parallel, and the sliding rods of the two supporting arms are integrated.

[0024] Preferably, the driving mechanism comprises:

[0025] a rack connected with the lower sliding rods;

[0026] a telescopic rod, one end of the telescopic rod being slidably inserted into the rack, and the other end of the telescopic rod being hingedly connected with the base;

[0027] a gear meshing with the rack;

[0028] a motor drivingly connected with the gear for driving the gear to rotate.

[0029] Preferably, the driving mechanism is a telescopic cylinder, and a piston rod of the cylinder is connected with the lower sliding rods.

[0030] In addition, the application further provides a use method of the buoyancy auxiliary lifting hydrogen fuel cell unmanned aerial vehicle, comprising the following steps:

[0031] lifting the lifting frame, pulling the half box body outward by the box body cable, so that the half box body is opened to expose the air bag, relaxing the air bag cable, and controlling the three-position three-way valve to be in the air bag inflation position, at this time, the air bag is inflated, and the air bag is unfolded outward;

[0032] when the air bag is inflated to a preset pressure value, the three-position three-way valve is controlled to be in the air bag maintaining position, the gas in the air bag is isolated, and the air bag realizes the buoyancy auxiliary lifting of the unmanned aerial vehicle;

[0033] controlling the three-position three-way valve to be in the air bag exhaust position, at the same time, tightening the air bag cable, under the extrusion action of the air bag cable, the hydrogen in the air bag is exhausted to the main pipeline through the T port of the three-position three-way valve, and finally flows to the fuel cell, the air bag is finally fixed on the bottom plate of the storage box by the air bag cable, and the lifting frame is lowered, after the pulling force of the box body cable is removed, the half box body contacts and covers the bottom plate under the action of the reset elastic element, the air bag is covered, and the air bag is stored in the storage box.

[0034] The application has the following beneficial effects:

[0035] This buoyancy-assisted hydrogen fuel cell drone, combined with the operating characteristics of a hydrogen fuel cell system, proposes a new gas configuration scheme. Through the linkage control of a three-position three-way valve and the airbag cable, it realizes the automatic inflation, automatic holding, and automatic deflation of the airbag. At the same time, with the addition of a liftable lifting frame and an openable and closable storage box, the lifting frame automatically deploys and the storage box automatically opens when the airbag is inflated, and the lifting frame automatically folds and the storage box automatically closes when the airbag is retracted, which has the advantage of automatically controlling the deployment and storage of the airbag. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and provide explanations, but do not constitute an undue limitation of this application. In the drawings:

[0037] Figure 1 This is a schematic diagram of the structure of the buoyancy-assisted hydrogen fuel cell drone described in this invention;

[0038] Figure 2 This is a schematic diagram of the storage box of the present invention installed on the lifting frame in the first position.

[0039] Figure 3 This is a schematic diagram of the storage box of the present invention installed on the lifting frame in a second position.

[0040] Figure 4 This is a schematic diagram of the first orientation structure of the airbag deployment according to the present invention;

[0041] Figure 5 This is a schematic diagram of the second orientation of the airbag deployment structure according to the present invention;

[0042] Figure 6 This is a schematic diagram of the lifting frame described in this invention.

[0043] Figure 7 This is a schematic diagram of the structure of the base of the lifting frame described in this invention;

[0044] Figure 8 This is a schematic diagram of the first gas configuration principle for the buoyancy-assisted hydrogen fuel cell drone described in this invention.

[0045] Figure 9 This is a schematic diagram of the second gas configuration principle for the buoyancy-assisted hydrogen fuel cell drone described in this invention.

[0046] Attached icon number

[0047] 1-Frame; 2-Rotor assembly; 3-Fuel cell; 4-Hydrogen tank; 5-Main pipeline; 6-Lifting frame; 6a-Base; 6b-Outrigger; 6b1-Arm; 6b2-Pivot; 6c-Drive mechanism; 6c1-Rack; 6c2-Telescopic rod; 6c3-Gear; 7-Storage box; 7a-Base plate; 7b-Half box; 7c-Reset elastic element; 7d-Box cable; 8-Airbag; 9-Branch pipeline; 10-Three-position three-way valve; 11-Airbag cable; 12-Cable retraction mechanism; 13-Limiting element; 14-Ejector; 15-Sliding plate; 16-Strip sliding hole; 17-Sliding rod. Detailed Implementation

[0048] The core of this invention is to provide a buoyancy-assisted hydrogen fuel cell drone with automated control of the deployment and retraction of the assisted airbag;

[0049] Another core aspect of this invention is to provide a method for using the aforementioned buoyancy-assisted hydrogen fuel cell drone.

[0050] 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.

[0051] Please refer to Figures 1 to 7 This invention discloses a buoyancy-assisted hydrogen fuel cell drone, including a frame 1, a rotor assembly 2, a fuel cell 3 and a hydrogen cylinder 4 mounted on the frame 1. The hydrogen cylinder 4 and the fuel cell 3 are connected by a main pipe 5, through which hydrogen is input to the fuel cell 3 to provide energy for the drone.

[0052] To reduce energy consumption and improve the drone's endurance, based on the "buoyancy-assisted" principle, the aforementioned drone also includes an auxiliary lifting structure mounted on the frame 1. Specifically, the auxiliary lifting mechanism includes a lifting frame 6, a storage box 7, and an airbag 8.

[0053] Specifically, the lifting frame 6 is installed on the top surface of the frame 1, and the lifting frame 6 has an extended state that is raised upwards and a folded state that is folded downwards.

[0054] The storage box 7 is fixed to the top of the lifting frame 6. The storage box 7 includes a base plate 7a and two half-boxes 7b hinged to both sides of the base plate 7a. Each half-box 7b has a reset elastic element 7c between itself and the base plate 7a. After the external force is removed, the half-boxes 7b contact and cover the base plate 7a under the action of their respective reset elastic elements 7c. Each half-box 7b is connected to the lifting frame 6 by a box cable 7d. When the lifting frame 6 is in the extended state, the half-boxes 7b move away from and expose the base plate 7a under the tension of their respective box cables 7d. Figure 2 As shown, when the lifting frame 6 is in the folded state, the box cable 7d does not apply tension to the half box 7b, and the half box 7b contacts and covers the bottom plate 7a under the action of the reset elastic member 7c; when the lifting frame 6 is in the unfolded state, the box cable 7d is taut and applies an outward pulling force to the half box 7b, overcoming the elastic force of the reset elastic member 7c and pulling the half box 7b away from and exposing the bottom plate 7a.

[0055] Airbag 8 is placed on base plate 7a, and airbag 8 is connected to a pipe 9 (see...) Figure 1 The branch pipe 9 is connected to the main pipe 5, and a three-position three-way valve 10 is installed on the branch pipe 9. Please refer to the reference. Figure 7 The T-port (i.e., return port) of the three-way valve is connected to the main pipe 5. When the gasbag 8 is venting, the hydrogen inside the gasbag 8 is discharged from the T-port of the three-way valve to the main pipe 5 and eventually flows to the fuel cell 3. It should be understood that the height of the gasbag 8 changes when it is deployed and retracted. Therefore, in actual use, the branch pipe 9 can be a flexible gas delivery pipe to adapt to the height change of the gasbag.

[0056] like Figure 2 , Figure 3 , Figure 4 As shown, several airbag cables 11 are arranged at intervals along the circumference of the outer wall of the airbag 8. The upper ends of the cables 11 converge at the center of the top of the airbag 8, and the lower end of each cable 11 slides through the outer wall of the airbag 8 and finally passes through the through hole in the bottom plate 7a and connects to a cable retraction mechanism 12. When the airbag deflates, the cable retraction mechanism 12 tightens the cables 11, which compresses the airbag. Under the compression of the cables 11, the hydrogen gas inside the airbag 8 is discharged to the main pipe 5 through the T port of the three-position three-way valve. Finally, the airbag 8 is fixed to the bottom plate 7a of the storage box 7 by the cables 11. Figure 5 As shown, in practical applications, several airbag cables 11 can pass through the bottom plate 7a of the storage box 7 and then be gathered together and connected to the cable retraction mechanism 12. In this way, the cable retraction mechanism 12 can simultaneously control the tightening or loosening of several cables 11.

[0057] It should be understood that the cable retraction mechanism 12 is used to tighten and loosen the airbag cable 11. This type of structure is common in the prior art and will not be described in detail here. For example, the cable retraction mechanism 12 can be an electric cable retraction mechanism, which can use the forward and reverse rotation of a servo motor to retract and loosen the airbag cable 11.

[0058] The above-mentioned method of using a buoyancy-assisted hydrogen fuel cell drone includes the following steps:

[0059] Raise the lifting frame 6 to pull the box cable 7d outward to open the half box 7b and expose the airbag 8. Release the airbag cable 11 and control the three-way valve 10 to be in the airbag inflation position (the three-way valve P port is open, A port is open, and T port is closed). Inflate the airbag 8 and the airbag will unfold outward.

[0060] When the airbag 8 is inflated to the preset pressure value, the three-position three-way valve 10 is controlled to be in the airbag holding position (the three-position three-way valve P port is closed, A port is closed, and T port is closed), the gas inside the airbag 8 is isolated, and the airbag 8 achieves buoyancy-assisted lifting of the drone.

[0061] The three-way valve is controlled to be in the airbag exhaust position (P port of the three-way valve is off, A port is open, and T port is open). At the same time, the airbag cable 11 is tightened. Under the compression of the airbag cable 11, the hydrogen in the airbag 8 is discharged to the main pipe 5 through the T port of the three-way valve and finally flows to the fuel cell 3. The airbag 8 is finally fixed to the bottom plate 7a of the storage box 7 by the airbag cable 11. The lifting frame 6 is lowered and the tension of the box cable 7d is removed. Under the action of the reset elastic element 7c, the half box 7b contacts and covers the bottom plate 7a, thereby covering the airbag 8 and storing the airbag 8 in the storage box 7.

[0062] It should be noted that the P port of the three-position three-way valve 10 is the air inlet, the A port is the working port, and the T port is the air return port.

[0063] As can be seen from the above technology, this buoyancy-assisted hydrogen fuel cell drone, combined with the operating characteristics of the hydrogen fuel cell system, proposes a new gas configuration scheme. Through the linkage control of the three-position three-way valve 10 and the airbag cable 11, the automatic inflation, automatic holding and automatic deflation of the airbag 8 are realized. At the same time, with the liftable lifting frame 6 and the openable and closable storage box 7, the lifting frame 6 automatically unfolds and the storage box 7 automatically opens when the airbag is inflated, and the lifting frame 6 automatically folds and the storage box 7 automatically closes when the airbag is retracted. It has the advantage of automatically controlling the deployment and storage of the airbag 8.

[0064] In further technical solutions, such as Figure 2 , Figure 4As shown, several limiting members 13 are fixedly provided on the outer wall of the airbag 8 along the extension direction of each airbag cable 11, and the airbag cables 11 slide through the limiting members 13 from top to bottom. The limiting members 13 limit the airbag cables 11, making the compression of the airbag 8 by the airbag cables 11 more uniform and efficient, and improving the degassing efficiency of the airbag 8.

[0065] Furthermore, in conjunction with references Figure 1 , Figure 9 An ejector 14 is also installed on the main pipe 5, and the T-port of the three-position three-way valve is connected to the inlet of the ejector 14 for the ejected fluid. During exhaust, the hydrogen gas in the gasbag 8 is ejected to the main pipe 5 and eventually flows to the fuel cell 3. At this time, through the ejection action of the ejector 14 and the compression action of the gasbag cable 11, the hydrogen gas in the gasbag 8 is simultaneously discharged, resulting in a higher exhaust efficiency. It is easy to understand that while adding the ejector 14 improves the exhaust efficiency of the gasbag, it also increases the manufacturing cost.

[0066] The aforementioned lifting frame 6 refers to a support structure for supporting the storage box 7, which allows for adjustments to the spatial height. It should be understood that the lifting frame 6 can have various structures. For example... Figure 2 , Figure 3 , Figure 6 , Figure 7 As shown, for example, the lifting frame 6 includes: a base 6a, a support arm 6b, and a drive mechanism 6c.

[0067] Specifically, the base 6a is fixed to the top of the frame 1.

[0068] The support arm 6b includes two pairs of arms arranged vertically. Each pair consists of two arms 6b1 arranged in a cross shape and rotatably connected at the center by a pivot 6b2. The lower end of the upper arm 6b1 is hinged to the upper end of the corresponding lower arm 6b1. The upper end of one of the upper arms 6b1 is hinged to the bottom plate 7a of the storage box 7, and the upper end of the other upper arm 6b1 is slidably connected to the bottom plate 7a of the storage box 7. The lower end of one of the lower arms 6b1 is hinged to the base 6a, and the lower end of the other lower arm 6b1 is slidably connected to the base 6a.

[0069] The drive mechanism 6c is connected to the arm 6b1, which is slidably connected to the base 6a below, so as to drive the lower end of the arm 6b1 to slide along the base 6a.

[0070] In practical applications, the drive mechanism drives the lower end of the corresponding arm 6b1 below to slide along the base 6a, thereby realizing the raising and lowering of the lifting frame 6.

[0071] Furthermore, one end of the box cable 7d is fixedly connected to the outer wall of the half-box 7b, and the other end of the box cable 7d is fixedly connected to the upper pivot 6b2 of the support arm 6b. When the lifting frame 6 is raised, the distance between the pivot 6b2 and the half-box 7b increases. At this time, the box cable 7d is tightened and pulls the half-box 7b outward, causing the half-box 7b to open. When the lifting frame 6 is lowered, the distance between the pivot 6b2 and the half-box 7b decreases. At this time, the box cable 7d is relaxed and no tension is applied to the half-box 7b. The half-box 7b closes under the action of its reset elastic element 7c.

[0072] In a preferred embodiment, both the base plate 7a and the base 6a are provided with sliding plates 15, each with a strip-shaped sliding hole 16. Sliding rods 17 are fixedly connected to the corresponding arm 6b1 of the sliding plate 15, and the sliding rods 17 are inserted into and slidably engaged with the strip-shaped sliding holes 16. In practical applications, the drive mechanism can drive the sliding rods 17 to slide along the strip-shaped sliding holes 16 to achieve the lifting and lowering of the lifting frame 6. The structure is simple and provides stable support.

[0073] Preferably, to improve the stability of the lifting frame 6, the number of outriggers 6b is two, such as... Figure 6 As shown, the two support arms are arranged in parallel, and the sliding rods 17 of the two support arms are connected as one unit. In actual use, the raising and lowering of the two support arms 6b can be controlled synchronously by the lower sliding rod 17. The two support arms can improve the stability of the support for the storage box 7.

[0074] In some implementation schemes, such as Figure 7 As shown, the drive mechanism includes a rack 6c1, a telescopic rod 6c2, a gear 6c3, and a motor. The rack 6c1 is connected to the sliding rod below it. One end of the telescopic rod 6c2 is slidably inserted into the rack 6c1, and the other end is hinged to the base 6a. The gear 6c3 meshes with the rack 6c1. The motor (not shown) is connected to the gear 6c3 to drive its rotation. In practical applications, in response to the motor drive, the forward and reverse rotation of the gear 6c3 controls the length of the telescopic rod 6c2 extending into the rack 6c1, thereby driving the sliding rod 17 to slide back and forth along the strip-shaped sliding hole 16, thus controlling the raising and lowering of the lifting frame 6.

[0075] In other embodiments, the drive mechanism 6c can also be a telescopic cylinder, with the piston rod of the cylinder connected to the lower sliding rod 17. The extension and retraction of the piston rod drives the sliding rod 17 to slide back and forth in the strip-shaped sliding hole. The specific structure of the drive mechanism 6c is not limited here, as long as it can drive the lower sliding rod 17 to slide back and forth along the strip-shaped sliding rod hole 16.

[0076] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0077] It should be understood that the use of terms such as "system," "device," "unit," and / or "module" in this application is merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0078] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0079] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more.

[0080] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0081] If a flowchart is used in this application, it is used to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0082] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A buoyancy-assisted hydrogen fuel cell unmanned aerial vehicle (UAV), comprising a frame, and a rotor assembly, a fuel cell, and a hydrogen tank mounted on the frame, wherein the hydrogen tank and the fuel cell are connected via a main pipeline; characterized in that, It also includes an auxiliary lifting mechanism mounted on the frame; The auxiliary lifting mechanism includes: The lifting frame installed on the top surface of the frame has an upward unfolded state and a downward folded state. A storage box fixed to the top of the lifting frame includes a base plate and two half-boxes hinged to both sides of the base plate. Each half-box is provided with a reset elastic element between itself and the base plate. After the external force is removed, the half-boxes contact and cover the base plate under the action of their respective reset elastic elements. Each half-box is provided with a box cable between itself and the lifting frame. When the lifting frame is in the unfolded state, the half-boxes move away from the base plate and are exposed under the tension of their respective box cables. An airbag is placed on the base plate. The airbag is connected to the main pipe through a pipe. A three-position three-way valve is installed on the pipe. The T-port of the three-position three-way valve is connected to the main pipe. Several airbag cables are arranged at intervals along the circumference of the airbag on its outer wall. The upper ends of the several airbag cables converge at the center of the top of the airbag. The lower end of each airbag cable slides through the outer wall of the airbag and finally passes through the through hole of the base plate and is connected to a cable retraction mechanism.

2. The buoyancy-assisted hydrogen fuel cell drone as described in claim 1, characterized in that, The outer wall of the airbag is fixedly provided with several limiting members along the extension direction of each airbag cable, and the airbag cables slide through the limiting members from top to bottom.

3. The buoyancy-assisted hydrogen fuel cell drone as described in claim 1, characterized in that, The main pipeline is also equipped with an ejector, and the T port of the three-position three-way valve is connected to the inlet of the ejector for the ejected fluid.

4. The buoyancy-assisted hydrogen fuel cell drone as described in claim 1, characterized in that, The lifting frame includes: a base, a support arm, and a drive mechanism; The base is fixed to the top of the frame; The outrigger includes two pairs of arms arranged vertically, each pair of arms consisting of two arms arranged in a cross shape and connected by a pivot in the middle. The lower end of the upper arm is hinged to the upper end of the corresponding lower arm; The upper end of one of the upper arms is hinged to the base plate, and the upper end of the other upper arm is slidably connected to the base plate; The lower end of one of the lower arms is hinged to the base, and the lower end of the other lower arm is slidably connected to the base; The drive mechanism is connected to the arm below and slidably connected to the base to drive the lower end of the arm to slide along the base.

5. The buoyancy-assisted hydrogen fuel cell drone as described in claim 4, characterized in that, One end of the box cable is fixed to the outer wall of the half-box, and the other end of the box cable is fixed to the upper pivot.

6. The buoyancy-assisted hydrogen fuel cell drone as described in claim 5, characterized in that, Both the base plate and the base are provided with sliding plates, and the sliding plates are provided with strip-shaped sliding holes. Each arm corresponding to the sliding plate is fixedly connected with a sliding rod, and the sliding rod is inserted into the strip-shaped sliding hole and slides in cooperation with the strip-shaped sliding hole.

7. The buoyancy-assisted hydrogen fuel cell drone as described in claim 6, characterized in that, The number of support arms is two, the two support arms are arranged in parallel, and the sliding rods of the two support arms are connected as one unit.

8. The buoyancy-assisted hydrogen fuel cell drone as described in claim 7, characterized in that, The drive mechanism includes: The rack is connected to the sliding rod below; A telescopic rod, one end of which can be slidably inserted into the rack, and the other end of which is hinged to the base; The gear meshes with the rack; An electric motor is connected to the gear transmission and is used to drive the gear to rotate.

9. The buoyancy-assisted hydrogen fuel cell drone as described in claim 7, characterized in that, The driving mechanism is a telescopic cylinder, and the piston rod of the cylinder is connected to the sliding rod below.

10. The method of using a buoyancy-assisted hydrogen fuel cell drone as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Raise the lifting frame to pull the box cable outwards to open the half box and expose the airbag. Release the airbag cable and control the three-position three-way valve to the airbag inflation position. Inflate the airbag and deploy it outwards. When the airbag is inflated to the preset pressure value, the three-position three-way valve is controlled to be in the airbag holding position, the gas inside the airbag is isolated, and the airbag achieves buoyancy assistance for the drone. The three-way valve is controlled to the airbag exhaust position. At the same time, the airbag cable is tightened. Under the compression of the airbag cable, the hydrogen in the airbag is discharged to the main pipeline through the T port of the three-way valve and finally flows to the fuel cell. The airbag is finally fixed to the bottom plate of the storage box by the airbag cable. After the lifting frame is lowered and the tension of the box cable is removed, the half box body contacts and covers the bottom plate under the action of the reset elastic element, thereby covering the airbag and storing the airbag in the storage box.

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