An aircraft cabin for a cross-medium water-air dual-use unmanned aerial vehicle and a design method

Abstract

The present invention discloses a cross-medium water-air dual-purpose unmanned aerial vehicle cabin and a design method, including a first housing. The shape of the first housing is semi-elliptical, a first flange is provided at the edge of the first housing, and protrusions are provided on the surface of the first housing; a second housing, the bottom surface of the second housing is a plane, the side wall of the second housing is an arc surface, a second flange is provided at the edge of the second housing, at least two groups of power system installation structures are provided on the side wall of the second housing, and a first through hole, a second through hole and a third through hole are respectively provided at the bottom of the second housing; an accommodation cavity is formed inside after the first housing and the second housing are connected through the first flange and the second flange; and a sealing structure is provided at the connection. By designing the surfaces of the first housing and the second housing into arc surfaces, the resistance of the aircraft cabin in different media of water and air can be effectively reduced, and the arc surface can improve the compression resistance and pressure resistance of the cabin. The provided sealing structure can enable the cabin to maintain good water tightness.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and particularly relates to a cross-medium water-air dual-purpose unmanned aircraft cabin and a design method thereof. Background Art

[0002] A cross-medium water-air dual-purpose unmanned aircraft is one that can adaptively achieve motion transition and continuous existence between two different fluid media, water and air, and can continuously navigate autonomously and perform specific tasks in both media. The rotary-wing cross-medium water-air dual-purpose unmanned aircraft has become an important research direction of cross-medium unmanned aircraft due to its advantages such as flexibility and no takeoff and landing site restrictions.

[0003] The cabin design of a cross-medium water-air dual-purpose unmanned aircraft needs to take into account the properties of two different fluids, water and air. There are many problems in the existing cross-medium water-air dual-purpose unmanned aircraft cabins, such as non-adaptability to the resistance of water and air, underwater pressure resistance, maximizing the space efficiency of the arrangement of onboard equipment systems, and the overall water tightness of the aircraft. Optimization design is required. In this regard, the present application proposes a cross-medium water-air dual-purpose unmanned aircraft cabin and a design method to solve such problems. Summary of the Invention

[0004] Based on this, in order to solve the problems existing in the prior art, the present application provides a cross-medium water-air dual-purpose unmanned aircraft cabin, including a first housing, the shape of the first housing is semi-ellipsoidal, a first flange is provided at the edge of the first housing, a protrusion is provided on the surface of the first housing, and the inside of the protrusion is a hollow structure;

[0005] A second housing, the bottom surface of the second housing is a plane, the side wall of the second housing is an arc surface, and a second flange is provided at the edge of the second housing;

[0006] The first housing and the second housing are connected through the first flange and the second flange, and an accommodation cavity is formed inside after the first housing and the second housing are connected, and the inside of the protrusion is communicated with the accommodation cavity;

[0007] The shapes and sizes of the first flange and the second flange are matched, and a sealing structure is provided at the connection of the first flange and the second flange.

[0008] Further, the connection between the protrusion and the first housing, and the connection between the side wall and the bottom surface of the second housing are both provided with round chamfers.

[0009] Further, the wall thickness of the first housing is 13.4149 mm, the wall thickness of the protrusion is 0.7548 mm, the wall thickness of the side wall of the second housing is 9.5273 mm, and the wall thickness of the bottom surface of the second housing is 17.5794 mm.

[0010] Further, the sealing structure includes a third flange, the third flange is disposed on the second flange and extends into the first housing, at least one first annular groove is formed on the second flange, at least one second annular groove is formed on a side of the third flange close to the inner wall of the first housing, each first annular groove is provided with a first sealing ring, and a part of the first sealing ring protrudes from the first annular groove, each second annular groove is provided with a second sealing ring, and a part of the second sealing ring protrudes from the first annular groove.

[0011] Further, a fixing structure with the same number and corresponding position as the power system installation structure is arranged inside the second housing. The fixing structure includes a first mounting block and a second mounting block fixedly connected to the second housing. A first mounting hole and a second mounting hole penetrate through the first mounting block. A first flange structure is arranged at a position corresponding to the first mounting hole on the first mounting block. At least two groups of first mounting brackets are arranged at positions corresponding to the second mounting holes on the second mounting block. At least two third mounting holes are arranged on the top surface of each first mounting block.

[0012] The present application provides a design method for a cross-medium water-air dual-use unmanned aerial vehicle cabin, which is used for the cross-medium water-air dual-use unmanned aerial vehicle cabin of any one of the above, and the method includes:

[0013] Determine relevant parameters according to the working environment and mission requirements of the cross-medium sea-air dual-use unmanned aerial vehicle;

[0014] Through the Reynolds number formula Calculate the Reynolds number R of the cabin e ;

[0015] Approximately fit the geometric shape of the cabin into a rotary ellipsoid to obtain the ellipsoidal rotary body curve of the cabin, and then obtain the wet surface area and drainage volume of the bare cabin according to integral operation;

[0016] After combining and substituting different friction drag coefficient formulas and empirical formulas, a constrained non-linear multi-variable function containing the length, width, and height of the cabin is obtained, and then the values of the length, width, and height of the cabin are determined through the MATLAB fmincon optimization solution function;

[0017] According to the determined length, width, and height of the cabin, accurately design the geometric shape of the cabin;

[0018] After the accurate geometric shape design of the cabin is completed, the pressure resistance design of the whole cabin is carried out in modules to determine the minimum wall thickness of each part of the cabin.

[0019] Further, the semi-empirical formula includes:

[0020] Among them,

[0021] Further, the semi-empirical formula further includes:

[0022] Among them,

[0023] Furthermore, the semi-empirical formula further includes:

[0024] Among them,

[0025] Furthermore,

[0026] Among them,

[0027] Beneficial effects: By designing the first shell as semi-ellipsoidal, the bottom surface of the second shell as a plane, and the side wall of the second shell as an arc surface, the resistance of the aircraft cabin in different water and air media can be effectively reduced. When the cabin is in water, the arc surface can improve the compression resistance and pressure resistance of the cabin, and the set sealing structure can enable the cabin to maintain good water tightness. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0029] Figure 1 It is a schematic diagram of the overall structure of the cabin of the cross-media water-air dual-use unmanned aircraft of the present invention;

[0030] Figure 2 It is a schematic diagram of the structure of the first shell of the cabin of the cross-media water-air dual-use unmanned aircraft of the present invention;

[0031] Figure 3 It is a bottom view of the second shell of the cabin of the cross-media water-air dual-use unmanned aircraft of the present invention;

[0032] Figure 4 It is a schematic diagram of the internal structure of the second shell of the cabin of the cross-media water-air dual-use unmanned aircraft of the present invention;

[0033] Figure 5 It is a schematic diagram of the cross-sectional structure of the cabin of the cross-media water-air dual-use unmanned aircraft of the present invention;

[0034] Figure 6 It is Figure 5 The enlarged view at A in

[0035] Figure 7 Data statistics of the MATLAB optimal solution for the present invention;

[0036] Figure 8 Multi - variable function graph of the Blasius formula and empirical formula one for the present invention;

[0037] Figure 9 Multi - variable function graph of the Blasius formula and empirical formula two for the present invention;

[0038] Figure 10 Multi - variable function graph of the Blasius formula and empirical formula three for the present invention;

[0039] Figure 11 Multi - variable function graph of the Blasius formula and empirical formula four for the present invention;

[0040] Figure 12 Multi - variable function graph of the recommended formula of the International Towing Tank Conference and empirical formula one for the present invention;

[0041] Figure 13 Multi - variable function graph of the recommended formula of the International Towing Tank Conference and empirical formula two for the present invention;

[0042] Figure 14 Multi - variable function graph of the recommended formula of the International Towing Tank Conference and empirical formula three for the present invention;

[0043] Figure 15 Multi - variable function graph of the recommended formula of the International Towing Tank Conference and empirical formula four for the present invention;

[0044] Figure 16 Multi - variable function graph of the Prandtl transitional flow friction resistance formula and empirical formula one for the present invention;

[0045] Figure 17 Multi - variable function graph of the Prandtl transitional flow friction resistance formula and empirical formula two for the present invention;

[0046] Figure 18 Multi - variable function graph of the Prandtl transitional flow friction resistance formula and empirical formula three for the present invention;

[0047] Figure 19 Multi - variable function graph of the Prandtl transitional flow friction resistance formula and empirical formula four for the present invention;

[0048] Figure 20 Multi - variable function graph of the Prandtl - Schlichting formula and empirical formula one for the present invention;

[0049] Figure 21 Multi - variable function graph of the Prandtl - Schlichting formula and empirical formula two for the present invention;

[0050] Figure 22It is the multi - variable function image of the Prandtl - Schlichting formula and the empirical formula three of the present invention;

[0051] Figure 23 It is the multi - variable function image of the Prandtl - Schlichting formula and the empirical formula four of the present invention;

[0052] In the figure: 1. The first housing; 11. The first flange; 12. The protrusion; 2. The second housing; 21. The second flange; 211. The first annular groove; 212. The first sealing ring; 22. The third flange; 221. The second annular groove; 222. The second sealing ring; 23. The first mounting hole; 24. The second mounting hole; 25. The fixing structure; 251. The first mounting block; 2511. The first flange structure; 2512. The third mounting hole; 252. The second mounting block; 2521. The first mounting frame; 26. The first through - hole; 261. The third annular groove; 262. The second flange structure; 27. The column; 271. The fourth mounting hole; 28. The second mounting frame; 29. The second through - hole; 291. The third through - hole.

[0053] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0055] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0056] In addition, the descriptions involving "first", "second", etc. in the present invention are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, "and / or" throughout the text includes three scenarios. Taking A and / or B as an example, it includes technical solution A, technical solution B, and the technical solution where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0057] An unmanned aerial vehicle generally includes components such as a lidar, an energy system, an airborne equipment system, a power system, a vector tilt system, a gas-liquid storage tank, a peristaltic pump, a servo, a sonar, a carbon fiber plate, a watertight integrated joint, and connecting cables, etc. And the cabin of the unmanned aerial vehicle in this application is used to load these unmanned aerial vehicle components mentioned above.

[0058] As Figure 1-4 shown, an embodiment of this application provides a cross-medium water-air dual-use unmanned aerial vehicle cabin, including a first housing 1. The shape of the first housing 1 is semi-ellipsoidal. A first flange 11 is provided at the edge of the first housing 1. A protrusion 12 is provided on the surface of the first housing 1, and the inside of the protrusion 12 is a hollow structure;

[0059] A second housing 2. The bottom surface of the second housing 2 is a plane, and the side wall of the second housing 2 is an arc surface. A second flange 21 is provided at the edge of the second housing 2. At least two groups of power system installation structures are provided on the side wall of the second housing 2. The power system installation structure includes a first mounting hole 23 and a second mounting hole 24, and the power system installation structures are symmetrically arranged on both sides of the second housing 2. First through holes 26, second through holes 29, and third through holes 291 are respectively opened at the bottom of the second housing 2, and the first through hole 26 is located in the middle of the bottom of the second housing 2;

[0060] The first housing 1 and the second housing 2 are connected through the first flange 11 and the second flange 21, and an accommodation cavity is formed inside after the first housing 1 and the second housing 2 are connected. The inside of the protrusion 12 is communicated with the accommodation cavity;

[0061] The shapes and sizes of the first flange 11 and the second flange 21 match, and a sealing structure is provided at the connection of the first flange 11 and the second flange 21.

[0062] In this embodiment, the connection between the first housing 1 and the second housing 2 is a detachable connection. Specifically, a number of screw holes with the same quantity and corresponding positions are provided on the first flange 11 and the second flange 21. The screw holes on the first flange 11 and the second flange 21 are tightly connected by nuts. Preferably, the specification of the thread is M5. After the first housing 1 and the second housing 2 are connected, they form a shape similar to an ellipsoid with a smooth surface.

[0063] The shapes of the first flange 11 and the second flange 21 are elliptical.

[0064] Preferably, the number of the power system installation structures is four groups, and the four groups of power system installation structures are symmetrically arranged on both sides of the second housing 2.

[0065] The provided sealing structure seals the connection between the first flange 11 and the second flange 21, which can prevent water from leaking into the engine room from the connection between the first flange 11 and the second flange 21 when in water.

[0066] A protrusion 12 is provided on the first housing 1, and the internal space of the protrusion 12 is used to place the lidar. The first mounting hole 23 and the second mounting hole 24 on the second housing 2 are used to install the arms of the unmanned aerial vehicle in the power system and cooperate with the watertight wiring of the power system. The first through hole 26 opened at the bottom of the second housing 2 is located at the center of the bottom of the second housing 2 and is used to cooperate with the assembly of the watertight integrated joint. The second through hole 29 is used for the sonar of the airborne equipment system to enter and exit the cable. The second through hole 29 is located on one side of the first through hole 26, and a number of screw holes arranged in a circumferential array are provided around the second through hole 29. The screw holes are used for the threaded fastening connection with the sonar of the airborne equipment system. The third through hole 291 is located on one side of the first through hole 26 and on the same side as the second through hole 29. The third through hole 291 is used to connect with a peristaltic pump for pumping and discharging water.

[0067] Among them, the materials of the first housing 1 and the second housing 2 are both transparent photosensitive resin. The first housing 1, the protrusion 12, and the first flange 11 are integrally formed, and the second housing 2 and the second flange 21 are integrally formed.

[0068] Through the surface design of setting the first housing 1 as a semi-ellipsoid, the bottom surface of the second housing 2 as a plane, and the side wall of the second housing as an arc surface, the resistance of the aircraft engine room in different media of water and air can be effectively reduced. And when the engine room is in water, the arc surface design of the first housing 1 and the second housing 2 can also improve the compressive and pressure resistance of the engine room. The provided sealing structure can make the engine room maintain good watertightness.

[0069] In one embodiment, the shape of the protrusion 12 is hemispherical, and the connection between the protrusion 12 and the first housing 1 is set as a round chamfer.

[0070] In this embodiment, by setting the shape of the protrusion 12 to a hemispherical shape and the connection between the protrusion 12 and the first housing 1 to a round chamfer, the purposes are as follows: firstly, the hemispherical protrusion 12 and the round chamfer can make the force be more evenly distributed at the connection, reducing the possibility of stress concentration and increasing the stability and durability of the structure; secondly, by designing the connection between the protrusion 12 and the first housing 1 as a round chamfer, the first housing 1 and the protrusion 12 form an overall streamline shape, which can reduce the turbulence and eddy currents generated when air or water flows through the object, thereby reducing the resistance.

[0071] Preferably, the connections between the protrusion 12 and the inner and outer walls of the first housing 1 are both round chamfers and have a continuous and smooth transition.

[0072] Preferably, the radius of the round chamfer at the connection between the protrusion 12 and the first housing 1 is 34 mm.

[0073] In one embodiment, the connection between the side wall and the bottom surface of the second housing 2 is set as a round chamfer.

[0074] In this embodiment, by setting the connection between the side wall and the bottom surface of the second housing 2 as a round chamfer, the purposes are as follows: firstly, the round chamfer can reduce the stress concentration at the connection between the plane and the arc surface, increasing the stability and durability of the structure; secondly, the round chamfer can reduce the resistance and turbulence of the fluid on the surface of the part, thereby improving the hydrodynamic performance.

[0075] In one embodiment, the wall thickness of the first housing 1 is 13.4149 mm, and the wall thickness of the protrusion 12 is 0.7548 mm.

[0076] In this embodiment, under the design requirements of ensuring the pressure resistance, water tightness, and arrangement of airborne equipment of the cabin, the resistance of the water-air cabin is minimized. Through calculation, the wall thickness of the first housing 1 is 13.4149 mm, and the wall thickness of the protrusion 12 is 0.7548 mm.

[0077] Specifically, when the semi-ellipsoidal first housing 1 bears a uniform external pressure, it can keep its spherical shape uniformly compressed. At this time, the uniform intermediate compressive stress is where P is the uniform external pressure; R is the intermediate radius of the first housing 1; t is the wall thickness of the first housing 1. At the same time, considering the requirements of safe operation, the stress σ of the shell plate of the first housing 1 is The obtained stress σ of the shell plate of the first housing 1 should satisfy: σ ≤ 0.85σ s , σ s is the yield strength of the material. For the transparent photosensitive resin, which is a brittle material, the minimum value of σ b is selected to replace σ s . In the verification of the first housing 1, the equivalent radius R d is used as the radius of the first housing 1. Among them, D0 is the inner diameter of the ellipsoid, D1 is the outer diameter of the ellipsoid, and H is the depth of the ellipsoid. According to the above content, the minimum wall thickness of the first shell 1 and the protrusion 12 of the cross-medium sea-air dual-purpose unmanned aircraft is theoretically calculated and determined.

[0078] In one embodiment, the wall thickness of the side wall of the second shell 2 is 9.5273 mm, and the wall thickness of the bottom surface of the second shell 2 is 17.5794 mm.

[0079] In this embodiment, while ensuring design requirements such as the pressure resistance, watertightness, and arrangement of airborne equipment of the cabin, the resistance of the water-air cabin is minimized. Through calculation, the wall thickness of the side wall of the second shell 2 is 9.5273 mm, and the wall thickness of the bottom surface of the second shell 2 is 17.5794 mm;

[0080] Specifically, when the semi-ellipsoidal second shell 2 bears a uniform external pressure, it can maintain the uniform compression of its spherical shape. At this time, the uniform intermediate compressive stress is where P is the uniform external pressure; R is the intermediate radius of the second shell 2; t is the wall thickness of the second shell 2. At the same time, considering the requirements of safe operation, the stress σ of the shell plate of the second shell 2 is The obtained stress σ of the shell plate of the second shell 2 should satisfy: σ ≤ 0.85σ s , σ s is the yield strength of the material. The transparent photosensitive resin is a brittle material, and the minimum value of σ b is selected to replace σ s . In the verification of the second shell 2, the equivalent radius R d is used as the radius of the second shell 2. Among them, D0 is the inner diameter of the ellipsoid, D1 is the outer diameter of the ellipsoid, and H is the depth of the ellipsoid. According to the above content, the minimum wall thickness of the side wall and the bottom surface of the second shell 2 of the cross-medium sea-air dual-purpose unmanned aircraft is theoretically calculated and determined.

[0081] In one embodiment, the second shell 2 is internally provided with fixed structures 25 having the same number and corresponding positions as the installation structures of the power system. The fixed structures 25 include a first installation block 251 and a second installation block 252 fixedly connected to the second shell 2. The first installation hole 23 and the second installation hole 24 penetrate through the first installation block 251. A first flange structure 2511 is provided at a position corresponding to the first installation hole 23 on the first installation block 251. At least two groups of first installation frames 2521 are provided at positions corresponding to the second installation hole 24 on the second installation block 252. At least two third installation holes 2512 are provided on the top surface of each first installation block 251.

[0082] In this embodiment, the first installation block 251 and the second installation block 252 are located in the upper part of the inner wall of the second shell 2 and protrude centripetally along the side wall of the second shell 2. The first installation block 251 and the second installation block 252 are integrally formed with the second shell 2, and the material is transparent photosensitive resin;

[0083] A first flange structure 2511 is provided at a position corresponding to the first mounting hole 23 on the first mounting block 251. The first flange structure 2511 is used to connect with the flange waterproof component in the waterproof integrated wiring device. A number of screw holes are also arranged in a circumferential array on the periphery of the first flange structure 2511. The screw holes are used to be tightly connected with the flange waterproof component in the waterproof integrated wiring device through nuts. Using flange connection can improve the water tightness of the connection part.

[0084] The second mounting hole 24 is used to cooperate with the installation of the vector tilting system and is rigidly connected to the carbon fiber arm in the independently designed vector tilting system. The second mounting block 252 is used to place the servo in the vector tilting system, and the first mounting bracket 2521 is used to fix the servo in the vector tilting system.

[0085] By providing the first mounting block 251 and the second mounting block 252, the second housing 2 can be assembled with the power system. After the assembly is completed, the space is reasonably used, and the provided first flange structure 2511 can also improve the water tightness.

[0086] In one embodiment, a third annular groove 261 and a second flange structure 262 are sequentially provided on the outer surface of the bottom of the second housing 2 around the first through hole 26.

[0087] In this embodiment, the provided second flange structure 262 is used to connect with the streamlined waterproof flange disk cover component in the waterproof integrated joint device, and the second flange structure 262 is connected with the streamlined waterproof flange disk cover component in the waterproof integrated joint device through nuts. By providing the third annular groove 261, the inside of the third annular groove 261 is used to place the waterproof wire combing rubber in the waterproof integrated joint device, and it is tightly connected with the waterproof wire combing rubber in the waterproof integrated joint device through nuts.

[0088] In one embodiment, a number of columns 27 are installed on the inner surface of the bottom of the second housing 2 around the first through hole 26. The columns 27 are arranged in a circumferential array around the first through hole 26.

[0089] In this embodiment, the column 27 is arranged at the center of the bottom of the second housing 2. The column 27 is used to bear the weight of the airborne equipment system, and a fourth mounting hole 271 is opened at the upper end of the column 27. The fourth mounting hole 271 is used to be tightly connected with the carbon fiber board of the airborne equipment system through nuts.

[0090] In one embodiment, a second mounting bracket 28 is further provided on the inner surface of the bottom of the second housing 2.

[0091] In this embodiment, the second mounting bracket 28 is arranged on the other side of the first through hole 26. The second mounting bracket 28 is used for the fixation of the gas-liquid storage tank.

[0092] AsFigure 5-6 As shown in Figure 5-6 , in one embodiment, the sealing structure includes a third flange 22 disposed on the second flange 21 and extending into the first housing 1. At least one first annular groove 211 is formed in the second flange 21, and at least one second annular groove 221 is formed on the side of the third flange 22 close to the inner wall of the first housing 1. Each first annular groove 211 is provided with a first sealing ring 212, and a part of the first sealing ring 212 protrudes from the first annular groove 211. Each second annular groove 221 is provided with a second sealing ring 222, and a part of the second sealing ring 222 protrudes from the first annular groove 211.

[0093] In this embodiment, the shapes of the first annular groove 211 and the second annular groove 221 are rectangular, aiming to be applicable to two sealing states of dynamic sealing and static sealing. The protruding part of the first sealing ring 212 abuts against the first flange 11, and the protruding part of the second sealing ring 222 abuts against the inner wall of the first housing 1;

[0094] Both the first sealing ring 212 and the second sealing ring 222 are watertight O-ring rubber seals. The reason for using watertight O-ring rubber seals is that after being compressed, the watertight O-ring rubber seals always tend to recover their original cross-section, generating a self-compressing force effect. In addition, a little silicone grease can be applied to the surfaces of the first sealing ring 212 and the second sealing ring 222 during use to compensate for the insufficient smoothness of the watertight O-ring rubber seals and the sealing surface and to play a lubricating role;

[0095] Preferably, the diameter of the first sealing ring 212 is smaller than that of the second sealing ring 222. The number of the first sealing rings 212 is two groups, and the number of the second sealing rings 222 is one group;

[0096] The compression ratios of the first sealing ring 212 and the second sealing ring 222 do not exceed 15%-20% of the original cross-section;

[0097] The third flange 22 is perpendicular to the second flange 21, and the third flange 22 and the second flange 21 are integrally formed, and the material is transparent photosensitive resin;

[0098] By horizontally arranging the first sealing ring 212 at the first flange 11 and vertically arranging the second sealing ring 222 at the second flange 21, such a double-sealing and staggered-sealing method can effectively improve the watertightness of the cabin.

[0099] The embodiment of the present application provides a design method for the cabin of a cross-media water-air dual-use unmanned aerial vehicle, which is used for the cabin of the cross-media water-air dual-use unmanned aerial vehicle in any one of the above, and the method includes:

[0100] Determine relevant parameters according to the working environment and mission requirements of the cross-media sea-air dual-use unmanned aerial vehicle;

[0101] Calculate the Reynolds number R of the cabin through the Reynolds number formulae ;

[0102] Approximate the geometry of the engine nacelle as a rotational ellipsoid to obtain the rotational ellipsoid curve of the engine nacelle, and then obtain the wetted surface area and displacement volume of the bare engine nacelle according to integral operations;

[0103] After combining and substituting different friction drag coefficient formulas with empirical formulas, a constrained non-linear multivariate function containing the length, width, and height of the engine nacelle is obtained, and then the values of the length, width, and height of the engine nacelle are determined through the MATLAB fmincon optimization solution function;

[0104] According to the determined length, width, and height of the engine nacelle, accurately design the geometric shape of the engine nacelle;

[0105] After completing the accurate geometric shape design of the engine nacelle, conduct pressure resistance design on the overall modular engine nacelle to determine the minimum wall thickness of each part of the engine nacelle.

[0106] In this embodiment, the relevant parameters include environmental parameters, basic parameters, and geometric parameters.

[0107] The Reynolds number formula is

[0108] The Blasius formula:

[0109] The Prandtl-Schlichting formula:

[0110] The formula recommended by the International Towing Tank Conference:

[0111] The Prandtl transitional flow friction drag formula:

[0112] Among them, the semi-empirical formula is:

[0113] Semi-empirical formula 1:

[0114] Among them,

[0115] Semi-empirical formula 2:

[0116] Among them,

[0117] Semi-empirical formula 3:

[0118] Among them,

[0119] Semi-empirical formula 4:

[0120] Among them,

[0121] Specifically, relevant environmental parameters are determined according to the working environment and mission requirements of the cross-media sea-air dual-purpose unmanned aircraft - the kinematic viscosity number of water v = 1.414×10 -6 m 2 / S, seawater density ρ max = 1.07×10 3 kg / m 3 ;

[0122] According to the design requirements of the cross-media sea-air dual-purpose unmanned aircraft, its basic parameters are determined - the underwater speed V ∈ [0, 2.573] m / s;

[0123] According to the maximum space efficiency of the arrangement of the airborne equipment system, the key geometric parameters of the cabin of the cross-media sea-air dual-purpose unmanned aircraft are obtained: the hull length L ∈ [0.46, 0.56] m, and the hull width and height d ∈ [0.28, 0.40] m;

[0124] Among them, when the underwater speed V takes the maximum value V max = 2.573 m / s, according to the Reynolds number formula based on the hull length the Reynolds number R e of the cabin is 1.819660537×10 6 L≈1.820×10 6 L;

[0125] Approximate the geometric shape of the cabin as a rotational ellipsoid. Take the origin of the coordinate system as the vertex of the bow of the cabin, the Ox axis points along the axis of the cabin towards the stern, and the Oy axis is perpendicular to the Ox axis upwards. Then the curve of the ellipsoidal rotational body of the cabin is According to integral operation, the wetted surface area of the bare cabin is The drainage volume of the cabin

[0126] Use the semi-empirical formula to estimate the underwater resistance of the cabin. First, calculate the friction resistance coefficient C f0 , then calculate the total resistance coefficient C D , and finally obtain the underwater resistance R t of the cabin. After substituting different combinations of friction resistance coefficient formulas and empirical formulas, the underwater resistance R t of the cabin is a constrained non-linear multi-variable function containing the length, width, and height of the cabin. Then, the values of the length, width, and height of the cabin are determined through the MATLAB fmincon optimization solution function;

[0127] Such as Figure 7-Figure 23As shown, through calculation and multivariate function graph, it is known that when the cabin length is 0.56m, and the width and height are 0.28m, the friction resistance of the entire cabin is the smallest.

[0128] The length of the cabin is determined to be 0.56m, and the width and height are determined to be 0.28m as geometric parameters. Then, under the constraints of key geometric parameters, the cabin shape is designed in detail according to the layout of the airborne equipment system to maximize the space efficiency, and the precise geometric shape of the cabin is determined. The lidar cabin cap 11 in the upper cabin 1 refers to the drag reduction design of the helicopter fuselage. The shape design of the nose (cockpit) is improved in the drag reduction design of the helicopter fuselage. When the fuselage head corner radius R e and fuselage width W F Ratio The fuselage resistance increases significantly when the fuselage head corner radius R e and fuselage width W F Ratio When the fuselage resistance is reduced and there is no obvious change, the laser radar cabin cap 11 in the upper cabin 1 adopts a smooth continuous fillet R34 transition to make the cabin

[0129] After the precise geometric design of the cabin is completed, the pressure resistance design of the cabin's entire modules is carried out to determine the minimum wall thickness of each part of the cabin;

[0130] Determine the relevant environmental parameters according to the working environment and mission requirements of the cross-medium sea-air dual-purpose unmanned aerial vehicle, the working depth range h∈[0,50]m, the seawater density ρ∈[1.02,1.07]g / cm 3 , gravitational acceleration g∈[9.780,9.832]m / s 2 , atmospheric pressure p 大气 =1.01325×10 5 pa, so the maximum working pressure p of the cross-medium sea and air dual-purpose unmanned aerial vehicle can be obtained max =ρ max g max h max +p 大气 =6.27337×10 5 pa, considering possible material defects, calculation formula errors, ultra-deep and overpressure in operation and other unsafe factors, the pressure hull subjected to external pressure should be designed and calculated according to the calculated pressure, which is taken as 1.5 times the maximum working pressure, so the calculated pressure P j =1.5p max =9.410055×10 5 pa;

[0131] According to the design requirements of the cross-media air-sea dual-purpose unmanned aerial vehicle, its cabin material is determined to be transparent photosensitive resin, and then the basic material parameters of tensile strength (tensile strength) σ are determined. b ∈[44×10 6 ,62×10 6 Pa.

[0132] When the ellipsoidal cabin bears a uniform external pressure, it can maintain its spherical shape and be uniformly compressed. At this time, the uniform intermediate compressive stress is where P is the uniform external pressure; R is the intermediate radius of the ellipsoidal cabin; t is the wall thickness of the ellipsoidal cabin. At the same time, considering the requirements of safe operation, the stress σ of the ellipsoidal cabin shell plate is The stress σ of the obtained ellipsoidal cabin shell plate should satisfy: σ ≤ 0.85σ s , σ s is the yield strength of the material. Since the transparent photosensitive resin is a brittle material, σ b The minimum value is selected to replace σ s ;

[0133] In the verification of the ellipsoidal shell, the equivalent radius R d is used as the radius of the spherical shell. where D0 is the inner diameter of the ellipsoid, D1 is the outer diameter of the ellipsoid, and H is the depth of the ellipsoid;

[0134] According to the above content, the minimum wall thickness of each part of the cross-media air-sea dual-purpose unmanned aerial vehicle is theoretically calculated and determined;

[0135] The first shell 1 is divided into two parts for pressure resistance design:

[0136] The protrusion 12 is approximated as a hemispherical shell. According to the above analysis and calculation, the minimum wall thickness of the shell plate is: t min = 0.7548 mm.

[0137] The first shell 1 is approximated as an ellipsoidal shell. According to the above analysis and calculation, the minimum wall thickness of the shell plate is: t min = 13.4149 mm.

[0138] The second shell 2 is divided into two parts for pressure resistance design:

[0139] The side wall of the second shell 2 is approximated as an ellipsoidal shell. According to the above analysis and calculation, the minimum wall thickness of the shell plate is: t min = 9.5273 mm.

[0140] The bottom surface of the second shell 2. The elliptical flat plate part at the bottom of the second shell 2 is approximated as a circular flat plate with fixed edges at the periphery. Therefore, the maximum stress of the flat plate can be obtained and the maximum stress is on the upper and lower surfaces at the edge of the plate, where R is the semi-major axis of the ellipse, and p takes the maximum working pressure p max , (σr ) max Take the minimum value of σ b and calculate to get: t min = 17.5794 mm.

[0141] In summary, the wall thickness of the cabin should be in the range of 0.7548 mm - 17.5794 mm. Optionally, in order to facilitate mass production and processing of the cabin, the overall wall thickness of the cabin can be taken as 15 mm, and a fillet with a radius of R5 is provided at the transition between the semi-ellipsoidal shell part and the bottom elliptical flat plate part of the second housing 2.

[0142] In addition, on the premise of ensuring the integrity and reliability of the cabin, the detailed design inside and outside the cabin is determined according to systems or component devices such as the power system, energy system, and airborne equipment system.

[0143] Through the above method, a cabin of a cross-media water-air dual-use unmanned aerial vehicle of the present application is designed, and has the following beneficial effects: realizing the minimum drag optimization design of the water-air cabin under the design requirements such as ensuring the pressure resistance, water tightness, and arrangement of airborne equipment of the cabin; combining other systems and components of the cross-media sea-air dual-use unmanned aerial vehicle for overall optimization design to ensure the overall integrity of the cabin; the special waterproof structures of the first housing 1 and the second housing 2 of the cabin, the cooperation between some positions of the cabin and relevant watertight structures, etc., enable the cross-media sea-air dual-use unmanned aerial vehicle to have good overall water tightness.

[0144] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural transformations made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A design method for the cabin of a cross-medium water-air dual-purpose unmanned aerial vehicle, which is used for the design of the cabin of a cross-medium water-air dual-purpose unmanned aerial vehicle. The cabin includes: A first shell, the shape of the first shell is semi-ellipsoidal, a first flange is provided at the edge of the first shell, protrusions are provided on the surface of the first shell, and the inside of the protrusions is a hollow structure; A second shell, the bottom surface of the second shell is a plane, the side wall of the second shell is an arc surface, and a second flange is provided at the edge of the second shell; The first shell and the second shell are connected through the first flange and the second flange, and an accommodation cavity is formed inside after the first shell and the second shell are connected, and the inside of the protrusions is communicated with the accommodation cavity; The shapes and sizes of the first flange and the second flange match, and a sealing structure is provided at the connection of the first flange and the second flange; It is characterized in that: Determine relevant parameters according to the working environment and mission requirements of the cross-medium sea-air dual-purpose unmanned aerial vehicle; Through the Reynolds number formula Calculate the Reynolds number R of the engine nacelle e ; Approximate the geometry of the engine room to a rotational ellipsoid to obtain the ellipsoidal rotational curve of the engine room. Then, based on integral operations, obtain the wetted surface area and displacement volume of the bare engine room. That is, take the origin of the coordinate system as the vertex at the bow of the engine room, the Ox axis along the axis of the engine room pointing to the stern, and the Oy axis perpendicular to the Ox axis upward. Then the ellipsoidal rotational curve of the engine room is According to integral operations, the wetted surface area of the bare engine room can be obtained as The displacement volume of the engine room L is the length of the boat, and d is the width of the boat; After combining and substituting different friction resistance coefficient formulas and empirical formulas, a constrained non-linear multi-variable function containing the length, width, and height of the cabin is obtained, and then the values of the length, width, and height of the cabin are determined through the MATLAB fmincon optimization solution function; According to the determined length, width, and height of the cabin, accurately design the geometric shape of the cabin; After completing the accurate geometric shape design of the cabin, conduct a pressure resistance design on the overall modular cabin to determine the minimum wall thickness of each part of the cabin; When the semi-ellipsoidal second shell is subjected to uniform external pressure, it can keep its spherical shape uniformly compressed. At this time, the uniform intermediate compressive stress is where P is the uniform external pressure; R is the intermediate radius of the second shell; t is the wall thickness of the second shell. At the same time, considering the requirements of safe operation, the stress σ of the second shell plate is The obtained stress σ of the second shell plate should satisfy: σ ≤ 0.85σ s , σ s is the yield strength of the material. The transparent photosensitive resin is a brittle material, and σ b is replaced by the minimum value instead of σ s . In the verification of the second shell, the equivalent radius R d is used as the radius of the second shell. where D0 is the inner diameter of the ellipsoid, D1 is the outer diameter of the ellipsoid, and H is the depth of the ellipsoid. According to the above content, the minimum wall thickness of the side wall and bottom surface of the second shell of the cross-media sea-air dual-use unmanned aircraft is calculated and determined theoretically.

2. The design method of the cabin of the cross-medium water-air dual-use unmanned aerial vehicle according to claim 1, characterized in that, The connection between the protrusions and the first shell, and the connection between the side wall and the bottom surface of the second shell are both set as round chamfers.

3. The design method of the cabin of the cross-media water-air dual-use unmanned aerial vehicle according to claim 1, characterized in that, The wall thickness of the first shell is 13.4149 mm, the wall thickness of the protrusions is 0.7548 mm, the wall thickness of the side wall of the second shell is 9.5273 mm, and the wall thickness of the bottom surface of the second shell is 17.5794 mm.

4. The design method of the cabin of the cross-medium water-air dual-purpose unmanned aerial vehicle according to claim 2, characterized in that, The sealing structure includes a third flange, the third flange is provided on the second flange and extends into the first shell, at least one first annular groove is opened on the second flange, at least one second annular groove is opened on the side of the third flange close to the inner wall of the first shell, each first annular groove is provided with a first sealing ring, and a part of the first sealing ring protrudes from the first annular groove, each second annular groove is provided with a second sealing ring, and a part of the second sealing ring protrudes from the first annular groove.

5. The design method of the cabin of the cross-medium water-air dual-use unmanned aerial vehicle according to claim 3, characterized in that, At least two groups of power system installation structures are provided on the side wall of the second shell. The power system installation structure includes a first installation hole and a second installation hole. Inside the second shell, there are fixed structures with the same number and corresponding positions as the power system installation structures. The fixed structure includes a first installation block and a second installation block fixedly connected to the second shell. The first installation hole and the second installation hole penetrate through the first installation block. A first flange structure is provided at the position corresponding to the first installation hole on the first installation block. At least two groups of first installation frames are provided at the position corresponding to the second installation hole on the second installation block. At least two third installation holes are provided on the top surface of each first installation block.

6. The design method of the cabin of the cross-medium water-air dual-use unmanned aerial vehicle according to claim 1, characterized in that The semi-empirical formula includes: Among them, 7. The design method of the cabin of the cross-medium water-air dual-use unmanned aerial vehicle according to claim 1, characterized in that, The semi-empirical formula further includes: Among them, A p = Ld, C ss = 3.397×10 -3 .

8. The design method of the cabin of the cross-media water-air dual-purpose unmanned aerial vehicle according to claim 1, characterized in that, The semi-empirical formula also includes: Among them, C D = C f (1 + k), 9. The design method of the cabin of the cross-medium water-air dual-use unmanned aerial vehicle according to claim 1, characterized in that, The semi-empirical formula further includes: Among them, C D = C f (1 + k),

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