A connecting structure of a bamboo fixed-wing unmanned aerial vehicle

Abstract

A connection structure for a bamboo-made fixed-wing unmanned aerial vehicle (UAV) belongs to the field of UAV technology. The bamboo-made fixed-wing UAV includes a nose, fuselage, wings, vertical tail, and horizontal tail. The nose and fuselage are connected by bamboo pins, the fuselage and wings are connected by bamboo pins, the horizontal tail and fuselage are connected by bamboo pins, and the vertical tail and horizontal tail are connected by a vertical tail main beam. The bamboo pins are made of bamboo fiber reinforced composite material. This invention's bamboo UAV connection structure increases the tensile and compressive stress area and the shear stress area, utilizing the fuselage structure to transfer the force of the connection structure to the fuselage, thereby improving torsional strength and reinforcing the connection strength between each component and the fuselage. The entire UAV is made of bamboo fiber reinforced composite material, resulting in a simple and lightweight structure that ensures low cost while enabling rapid production and convenient assembly.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) technology, specifically relating to a connection structure for a bamboo-made fixed-wing UAV. Background Technology

[0002] Fixed-wing drones, with their long endurance and high flight stability, are widely used in surveying, inspection, and other fields. With the development of drone technology, lightweighting, low cost, and ease of assembly have become important research directions. Bamboo fiber reinforced composite materials, due to their advantages such as low density, high strength, environmental friendliness, and low cost, are increasingly being used in drone structural manufacturing.

[0003] However, the existing connection structures for fixed-wing drones have many drawbacks when used for bamboo drones: the tensile and compressive stress area of ​​the connection is limited, and stress concentration during flight can easily lead to loosening or breakage of the connection; secondly, the shear stress performance is insufficient, and the shear resistance at the joint is weak; some connection structures are complex in design, using multiple sets of bolts or adhesives for fixing, resulting in low assembly efficiency and difficulty in later maintenance; at the same time, there are problems such as high cost, long production cycle, and difficulty in obtaining local materials.

[0004] To this end, those skilled in the art selected bamboo as the core material through field research and prepared bamboo fiber reinforced composite materials, which were then applied to the processing and manufacturing of various components of bamboo drones. At the same time, a series of experiments were conducted to develop a special connection structure adapted to bamboo fixed-wing drones, thereby addressing the aforementioned technical problems in a targeted manner. Summary of the Invention

[0005] To address the problems of inconvenient assembly and weak load-bearing capacity in existing connection methods, this invention provides a connection structure for a bamboo-based fixed-wing drone, belonging to the field of drone technology. The bamboo-based fixed-wing drone includes a nose, fuselage, wings, vertical tail, and horizontal tail. The nose and fuselage are connected by bamboo pegs, as are the fuselage and wings, and the horizontal tail and fuselage. The vertical tail and horizontal tail are connected by a vertical tail main beam. The bamboo pegs are made of bamboo fiber reinforced composite material. This invention's bamboo drone connection structure increases the tensile and compressive stress area and the shear stress area, utilizing the fuselage structure to transfer the force of the connection structure to the fuselage, thereby improving torsional strength and reinforcing the connection strength between each component and the fuselage. The entire drone is made of bamboo fiber reinforced composite material, resulting in a simple and lightweight structure that ensures low cost while enabling rapid production and convenient assembly.

[0006] A connection structure for a bamboo-made fixed-wing drone, such as Figure 1 As shown, the bamboo fixed-wing UAV includes a nose (1), a fuselage (2), a wing (3) and a tail (10); the nose (1) is fixedly connected to the fuselage (2), the wing (3) is fixedly connected to the fuselage (2), and the tail (10) is fixedly connected to the fuselage (2).

[0007] Furthermore, the fixed connection is a bamboo pin connection, and the bamboo pin is made of bamboo fiber reinforced composite material.

[0008] Furthermore, the nose (1) includes a fuselage upper plate (8), a nose side plate (11), a nose bottom plate (12), a nose tail end support plate (9), and an external fastener (10); the fuselage (2) includes a fuselage upper plate (13) at the nose, a fuselage front end support plate (14), a fuselage bottom plate (15), a fuselage upper plate (16) at the wing, a fuselage support plate (17) at the wing box, a fuselage side plate (18), a fuselage upper plate (19) at the tail wing, and a fuselage tail end plate (33).

[0009] The head and tail support partition (9), the front support partition (14) and the tail support partition (33) are parallel and upright in sequence, with protrusions distributed around them;

[0010] The end of the upper plate (8) is positioned above the front end of the upper plate (13) at the head of the machine. The end of the upper plate (8) and the front end of the upper plate (13) at the head of the machine are provided with two rows of overlapping slots. The two rows of slots are respectively matched with the bosses at the upper ends of the support partition (9) at the tail end of the head of the machine and the support partition (14) at the front end of the machine body, thereby achieving a fixed connection. A boss is provided at the part where the side of the upper plate (8) contacts the side plate (11) at the head of the machine. A boss is provided at the part where the side of the upper plate (13) at the head of the machine contacts the side plate (18) at the body of the machine. The extended upper plate (13) at the head of the machine and the extended upper plate (8) at the head of the machine are connected together to enhance the connection strength at the top.

[0011] The machine head base plate (12) is placed below the machine head tail end support partition (9); the machine head base plate (12) has slots distributed at its end, which match the boss at the lower end of the machine head tail end support partition (9), thereby realizing the connection between the machine head tail end support partition and the machine head base plate; the machine head base plate (12) has a boss at the part where it contacts the machine head side plate (11);

[0012] The machine head side plate (11) is parallel and upright, and is distributed at the left and right ends of the machine head tail support partition (9); the machine head side plate (11) has grooves around its perimeter, which match the bosses at the contact points of the machine body upper plate (8), the machine head bottom plate (12) and the machine head tail support partition (9), thereby achieving a fixed connection.

[0013] The fuselage base plate (15) is located below the front support partition (14) and the rear partition (33) of the fuselage; the front and rear ends of the fuselage base plate (15) are provided with slots, which match the bosses at the lower ends of the front support partition (14) and the rear partition (33) of the fuselage, thereby realizing the connection between the fuselage base plate, the front support partition and the rear partition; the side of the fuselage base plate (15) that contacts the fuselage side plate (18) is provided with a boss;

[0014] The fuselage side plates (18) are parallel and upright, and are distributed at the left and right ends of the front support partition (14) and the rear partition (33) of the fuselage. The fuselage side plates (18) are surrounded by slots, which are matched with the bosses at the contact parts of the upper plate (13) of the fuselage head, the bottom plate (15) of the fuselage, the front support partition (14) of the fuselage and the rear partition (33) of the fuselage, thereby achieving a fixed connection.

[0015] The external fastener (10) has openings at both ends. One end of the opening overlaps with the slots at the end of the head side plate (11) and the end of the head bottom plate (12); the other end of the opening overlaps with the slots at the front end of the body side plate (18) and the front end of the body bottom plate (15). The bamboo pin passes through the external fastener (10), the head side plate (11) and the body side plate (18) in sequence to connect the head side plate (11) and the body side plate (18). The bamboo pin passes through the external fastener (10), the head bottom plate (12) and the body bottom plate (15) in sequence to connect the head bottom plate (12) and the body bottom plate (15).

[0016] The front end of the fuselage upper plate (16) at the wing is connected to the fuselage upper plate (13) at the nose, the rear end is connected to the fuselage upper plate (19) at the tail, and the left and right sides are connected to the fuselage side plates (18).

[0017] The fuselage support partition (17) at the wing box and the fuselage front support partition (14) are parallel. The upper end of the fuselage support partition (17) at the wing box is connected to the fuselage upper plate (16) at the wing, and the lower end is connected to the fuselage bottom plate (15). The left and right sides are fixedly connected to the fuselage side plates (18). The fuselage support partition (17) at the wing box is used to support the fuselage (2). As shown in Figure 2(a), Figure 2(b) and Figure 3 As shown.

[0018] Furthermore, the external fastener (10) consists of two square plates, which are placed on the inner and outer sides of the head base plate (12), the body base plate (15), the head side plate (11), and the body side plate (18). Each square plate has two openings, which are symmetrically positioned to evenly distribute structural stress and enhance connection strength.

[0019] Furthermore, the wing (3) includes a wing box (6) and a wing surface (7); the wing box (6) includes a wing box support partition (20), a wing box support partition (21), a wing box support partition (22), an inner wing rib (23) of the wing box boundary, an outer wing rib (24) of the wing box boundary, and a connecting support beam (25).

[0020] The wing box support partition (20), wing box support partition (21) and wing box support partition (22) are all square plates, each with a boss at the bottom and a slot on the boss; at the same time, there are bosses at the left and right ends; the wing box support partition (20), wing box support partition (21) and wing box support partition (22) are evenly parallel and upright above the fuselage upper plate (16) at the wing; the contact parts between the fuselage upper plate (16) at the wing and the wing box support partition (20), wing box support partition (21) and wing box support partition (22) are all provided with slots, and the slots are connected with the bosses with slots, thereby realizing the initial connection between the fuselage upper plate (16) at the wing and the wing box support partition (20), wing box support partition (21) and wing box support partition (22); the fuselage upper plate (16) at the wing is provided with bosses on the left and right sides, and there are slots on the bosses;

[0021] The inner wing rib (23) and outer wing rib (24) of the wing box boundary are respectively placed on the inner and outer sides of the fuselage side plate (18), and are provided with horizontal and vertical slots. The vertical slots are matched with the bosses at the left and right ends of the wing box support partition (20), wing box support partition (21) and wing box support partition (22), respectively. The horizontal slots are matched with the bosses on the left and right sides of the fuselage upper plate (16) at the wing. The bosses with slots on the left and right sides of the fuselage upper plate (16) at the wing pass through the inner wing rib (23), fuselage side plate (18) and outer wing rib (24) of the wing box boundary in turn. The slots on the bosses are matched with bamboo pins to achieve a stable connection between the fuselage upper plate (16) at the wing and the fuselage side plate (18).

[0022] The connecting support beam (25) is located at the bottom of the fuselage plate (16) at the wing, and passes laterally through the slot at the top of the fuselage support partition (17) at the wing box, the slot at the bottom of the boss of the wing box support partition (20), the slot at the bottom of the boss of the wing box support partition (21), and the slot at the bottom of the boss of the wing box support partition (22); thereby achieving a stable connection between the fuselage plate (16) at the wing, the fuselage support partition (17) at the wing box, the wing box support partition (20), the wing box support partition (21), and the wing box support partition (22); as shown in Figures 5(a) and 5(b).

[0023] Furthermore, the tail fin (10) includes a vertical tail (4) and a horizontal tail (5), the vertical tail (4) and the horizontal tail (5) being fixedly connected; the horizontal tail (5) includes a tail fin positioning support plate (30), a horizontal tail upper plate (26), a horizontal tail side plate (27), a horizontal tail main beam (28), and a horizontal tail rear wall (32); the vertical tail (4) includes a vertical tail root wing rib (31) and a vertical tail main beam (29);

[0024] The tail fin positioning support plate (30) is perpendicular to the upper plate (26) of the horizontal stabilizer and the upper plate (19) of the fuselage at the tail fin, and the side plate (27) of the horizontal stabilizer is parallel to the tail fin positioning support plate (30).

[0025] The tail fin positioning support plate (30) has a perforated boss at both the upper and lower ends, a through hole in the middle, and a groove at the rear end. The upper boss matches the slot in the middle of the horizontal tail upper plate (26) and the slot in the vertical tail root wing rib (31). The lower boss matches the slot on the fuselage upper plate (19) at the tail fin. The size of the through hole in the middle is the same as the cross-sectional size of the horizontal tail main beam (28). The protrusion formed by the groove at the rear end matches the slot in the horizontal tail rear wall (32), and the lower boss at the rear end matches the slot at the end of the vertical tail main beam (29).

[0026] The horizontal tail side plate (27) has slots at both the top and bottom, and a through hole in the middle. The upper slot matches the boss on the side of the horizontal tail upper plate (26). The lower slot matches the boss with slots on both sides of the upper plate (19) of the tail fin. The through hole in the middle has the same cross-sectional dimensions as the horizontal tail main beam (28) and the horizontal tail rear wall (32). The bosses on both sides of the upper plate (19) of the tail fin pass through the horizontal tail side plate (27) and are fixedly connected to the slots on the bosses by bamboo pins.

[0027] The tail beam (29) is a box beam with a slotted end extending from the end of the rear plate. The tail beam (29) is located vertically in the middle of the tail root rib (31), and the tail root rib (31) has a through hole with the same cross-sectional size as the tail beam (29).

[0028] The upper boss of the tail fin positioning support plate (30) passes through the corresponding slots on the upper plate of the horizontal stabilizer (26) and the root wing rib (31) of the vertical stabilizer. A bamboo pin then fixes the upper boss to the slot, thus achieving a fixed connection between the tail fin positioning support plate (30) and the upper plate of the horizontal stabilizer (26) and the root wing rib (31) of the vertical stabilizer. The lower boss mates with the slot on the fuselage upper plate (19) at the tail fin, and a bamboo pin then fixes the lower boss to the slot, thus achieving a fixed connection between the tail fin and the fuselage upper plate (26) and the root wing rib (31). The body plate (19) is fixedly connected to the tail fin positioning support plate (30); the horizontal tail main beam (28) and the horizontal tail rear wall (32) pass through the through holes in the middle of the horizontal tail side plate (27), the tail fin positioning support plate (30) and the horizontal tail side plate (27) respectively, so as to realize the mutual connection of the tail fin positioning support plate, the horizontal tail main beam and the horizontal tail rear wall; the horizontal tail side plate (27) is provided with slots, which are connected with the perforated bosses on both sides of the body plate (19) at the tail fin and then fixed with bamboo pins;

[0029] The extended portion of the vertical tail main beam (29) passes through the slots on the upper plate (26) of the horizontal tail and the upper plate (19) of the fuselage at the tail fin in sequence; the two protrusions formed by the groove at the rear end of the tail fin positioning support plate (30) pass through the slot in the middle of the horizontal tail rear wall (32) and the slot at the extended portion of the vertical tail main beam (29) respectively, and are fixed by bamboo pins in conjunction with the slot at the extended portion of the vertical tail main beam (29), thereby making a stable connection.

[0030] The middle part of the tail fin positioning support plate is connected to the horizontal stabilizer main beam, and the upper end is connected to the upper plate of the horizontal stabilizer and the wing rib at the root of the vertical stabilizer. The connection method effectively transfers the aerodynamic load borne by the vertical stabilizer to the main fuselage structure. After the connection is made by the cooperation of the boss and the slot, the bamboo pin is used for limiting and fixing. This double fixing structure can reliably resist the tensile and pull loads generated by the vertical stabilizer during flight. At the same time, it forms a reliable shear-resistant connection interface, which significantly enhances the structure's resistance to shear loads during flight, as shown in Figure 6(a) and Figure 6(b).

[0031] Furthermore, the nose (1), fuselage (2), wings (3) and tail (10) are all made of bamboo fiber reinforced composite material; the structure is simple and lightweight, ensuring low cost while enabling rapid production and convenient assembly.

[0032] Furthermore, the outer wing rib (24) and inner wing rib (23) of the wing box boundary are both composed of two parallel layers of bamboo boards, which are made of bamboo fiber reinforced composite material. The outer wing rib (24) and inner wing rib (23) of the wing box boundary are symmetrically distributed on both sides of the fuselage side panel (18) and are closely fitted with the fuselage side panel (18) and the fuselage upper panel (16) at the wing, in order to improve the shear stress performance of the connection parts.

[0033] Compared with the prior art, the present invention has the following beneficial technical effects:

[0034] The aircraft boasts excellent overall load-bearing performance and a stable and reliable structure: Wings: The connecting support beams expand the load-bearing area at the connection points; the inner and outer wing rib structures at the wing box boundary significantly increase the shear resistance at the junction of the fuselage and wing box; Nose: The internal fasteners are connected to the nose and fuselage bulkheads via pins for secondary fixation, effectively balancing the force couple and diffusing and transferring stress, thus enhancing the shear resistance and overall stability at the junction of the nose and fuselage; Tail: The one-piece molded tail positioning support plate serves as the core force transmission path, secured by upper and lower bosses and bamboo pins, efficiently transmitting tensile, compressive, and shear loads and avoiding stress concentration;

[0035] Excellent anti-slip performance: All key connection nodes (such as tail and fuselage, wing and fuselage, nose and fuselage) use bamboo pins with corresponding bosses and slots for precise fit; this design effectively limits the relative sliding of components under flight loads, ensuring assembly accuracy and structural tightness for long-term use, and preventing safety hazards caused by loosening; by increasing the tensile and compressive stress area and increasing the shear stress area, the stress of the connection structure is transferred to the fuselage using the fuselage structure, improving torsional strength and strengthening the connection strength between each component and the fuselage; all components of this invention are made of bamboo fiber reinforced composite material, which is simple in structure and lightweight, ensuring low cost while enabling rapid production and convenient assembly;

[0036] Achieving comprehensive lightweighting and high environmental protection: The entire aircraft is made of bamboo fiber reinforced composite material; this material has high specific strength, which significantly reduces the overall weight of the drone while ensuring structural rigidity; at the same time, bamboo is renewable and biodegradable, and the entire production and use process is environmentally friendly and pollution-free.

[0037] Low production cost, suitable for large-scale manufacturing: Bamboo fiber raw materials are widely available and inexpensive; all complex-shaped structural parts can be integrally molded by molds, the process is simple, the production efficiency is high, and the consistency is good, making it very suitable for low-cost, large-scale industrial production;

[0038] Assembly and maintenance are extremely convenient: the entire machine abandons the traditional complex bolt fastening process and adopts a unified modular connection method of "boss-slot-bamboo pin"; the assembly process does not require professional tools or superb skills and can achieve rapid assembly and disassembly; this not only greatly reduces the threshold for use, but also greatly improves the product's portability and field maintenance efficiency. Attached Figure Description

[0039] Figure 1 This is the overall structure of the present invention;

[0040] Figure 2(a) is an isometric view of the machine head;

[0041] Figure 2(b) is a cross-sectional view of the left side of the machine head;

[0042] Figure 3 This is the fuselage structure of the present invention;

[0043] Figure 4 The wing structure of this invention;

[0044] Figure 5(a) is an exploded view of the fuselage and wing connection structure;

[0045] Figure 5(b) is a left-side parabolic view of the fuselage-wing connection structure;

[0046] Figure 6(a) is a front view of the tail fin structure;

[0047] Figure 6(b) is a left-side structural diagram of the tail fin;

[0048] In the diagram, 1 is the nose, 2 is the fuselage, 3 is the wing, 4 is the vertical stabilizer, 5 is the horizontal stabilizer, 6 is the wing box, 7 is the wing surface, 8 is the nose upper plate, 9 is the nose and tail support bulkhead, 10 is the external fastener, 11 is the nose side plate, 12 is the nose bottom plate, 13 is the fuselage upper plate at the nose, 14 is the fuselage front support bulkhead, 15 is the fuselage bottom plate, 16 is the fuselage upper plate at the wing, 17 is the fuselage support bulkhead at the wing box, 18 is the fuselage side plate, and 19 is the tail. 20 is the fuselage upper plate, 21 is the wing box support bulkhead 1, 22 is the wing box support bulkhead 2, 23 is the inner wing rib of the wing box boundary, 24 is the outer wing rib of the wing box boundary, 25 is the connecting support beam, 26 is the horizontal tail upper plate, 27 is the horizontal tail side plate, 28 is the horizontal tail main beam, 29 is the vertical tail main beam, 30 is the tail fin positioning support plate, 31 is the vertical tail root rib, 32 is the horizontal tail rear wall, 33 is the fuselage tail end bulkhead. Detailed Implementation

[0049] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0050] The present invention provides a connection structure between the nose 1 and the fuselage 2 of a bamboo fixed-wing UAV, the specific implementation of which is as follows:

[0051] like Figures 1 to 3 As shown, a connection structure between the nose 1 and the fuselage 2 of a bamboo fixed-wing UAV includes a nose side plate 11, a nose bottom plate 12, a fuselage side plate 18, a fuselage bottom plate 15, a fuselage upper plate 13 at the nose, a nose upper plate 8, a fuselage front support partition 14, a nose rear support partition 9, a fastener 10, and bamboo pins. All components are made of bamboo fiber reinforced composite material and are integrally molded using a mold.

[0052] The machine head side plate 11 is symmetrically arranged, and its lower end is pre-fixed to the machine head base plate 12 by mortise and tenon structure. Two symmetrically distributed slots are opened in the middle of the machine head side plate 11 near the machine body connection end to ensure a reasonable stress transmission path.

[0053] The machine head base plate 12 has positioning slots on both sides where it fits with the machine head side plate 11, and two fasteners 10 are symmetrically arranged in the middle of the machine head base plate 12.

[0054] Both the upper plate 13 and the upper plate 8 of the machine head adopt a stretching design, and the extended part is provided with slots. The extended part of the upper plate 8 of the machine head covers the surface of the upper plate 13 of the machine head and ensures that the slots are in the same position to achieve surface contact at the top.

[0055] The front support partition 14 of the fuselage and the rear support partition 9 of the head are arranged in parallel, and the distance between them is adapted to the length of the fastener 10. The edges of the partitions are provided with slots that match the fastener 10, which are used to accommodate the fastener 10 and achieve vertical positioning. At the same time, the top of the partition is provided with a boss that matches and is fixedly connected to the slots at the overlapping part of the upper plate of the head and the upper plate of the head.

[0056] The fastener 10 is a rectangular sheet structure, and each connection part exists in pairs. It is symmetrically distributed on the inner and outer sides of the machine body side plate 18 and the machine head side plate 11. The fastener 10 has through holes at both ends that are compatible with bamboo pins.

[0057] Bamboo pins are made of bamboo fiber reinforced composite material that has been treated with anti-corrosion. The diameter is interference fit with the slots and through holes of each component, and the length is adapted to the assembly thickness. The surface of the pin is treated with anti-slip texture to enhance the stability after assembly.

[0058] Pre-assemble the head assembly: The head side plate 11 and the head bottom plate 12 are spliced ​​and fixed by mortise and tenon structure to ensure that the slots of the two are aligned; the head tail support partition 9 is embedded into the pre-set slot inside the head assembly and fixed with adhesive.

[0059] The second step is to pre-assemble the fuselage components: fix the front support partition 14 of the fuselage to the preset position inside the fuselage, and ensure that its slots correspond to the slots of the side panel 18 of the fuselage; place the upper panel of the fuselage on the extended boss of the front support partition 14 of the fuselage and align the mounting holes.

[0060] The third step is to connect the machine head and the body: insert the connecting end of the machine head assembly into the preset mounting position of the body assembly, so that the machine head side plate 11 and the body side plate 18 fit together; the slot provided at the extended part of the upper plate 13 of the machine head mates with the boss of the tail support plate 9 of the machine head; the extended part of the upper plate 8 of the machine head covers the upper surface of the upper plate 13 of the machine head and is locked onto the extended boss of the front support plate 14 of the body; the mounting slot of the fastener of the tail support plate 9 of the machine head and the front support plate 14 of the body are aligned; at this time, all slots and through holes are collinear.

[0061] Fourth step, install the fastener 10 and bamboo pins: Install the external fastener 10 on the inner and outer sides of the machine body side plate 18, the machine head side plate 11 and the machine head bottom plate 12 at the preset positions, and ensure that the through hole of the external fastener 10 is aligned with the corresponding slot hole; insert the bamboo pin from one side, through the external fastener 10, the side plate / bottom plate and all other components, until it comes out from the other side, to complete the axial fixation.

[0062] Step 5, Inspection and Reinforcement: After assembly, check the connection gap between the machine head 1 and the machine body 2 (gap ≤ 0.2mm) to ensure there is no looseness; wrap the exposed parts of the pins with waterproof tape to prevent moisture from entering and affecting the connection stability.

[0063] As shown in Figures 5(a) and 5(b), the present invention provides a connection structure between the wing 3 and the fuselage 2 of a bamboo fixed-wing UAV, the specific implementation of which is as follows:

[0064] The wing box support partition 20-22 is made of bamboo fiber reinforced composite material and prepared by hot pressing to ensure a dense structure free from warping and cracks. The wing box support partition 20-22 is vertically installed inside the wing box, with a downward-extending boss at its bottom. A rectangular slot is formed on the boss, the length and width of which are adapted to the cross-section of the connecting support beam 25, with tolerances controlled within ±0.24mm. Furthermore, the edge of the slot is flush with the bottom boundary of the fuselage upper plate 16 at the wing, ensuring assembly accuracy.

[0065] The connecting support beams 25 are evenly distributed along the length of the fuselage upper plate 4. Each support beam has a rectangular cross-section. During installation, the connecting support beams 25 are inserted from the bottom of the fuselage upper plate 16 at the wing into the slots of the wing box support partitions 20-22 and fixed with epoxy resin adhesive to form a stable beam support structure, effectively increasing the tensile and compressive stress area.

[0066] The inner and outer wing ribs of the wing box are symmetrically arranged on both sides of the fuselage side plate 18. The pre-compression process ensures a tight fit with the fuselage side plate 18, which significantly improves the shear stress performance.

[0067] The fuselage plate 16 at the wing is molded from bamboo fiber reinforced composite material. Each boss has a rectangular slot, the length and width of which are precisely matched with the cross-sectional dimensions of the bamboo pin (tolerance ±0.24mm). During installation, the bosses on both sides of the fuselage plate 4 are passed through the pre-positioned inner wing rib 23 of the wing box boundary, the fuselage side plate 18, and the outer wing rib 24 of the wing box boundary. Then, the bamboo pins are pressed into the slots to complete the final fixation and restrict the lateral sliding of the wing box boundary ribs.

[0068] In the actual assembly process, the assembly steps are as follows:

[0069] Pre-treatment: Clean all bamboo components thoroughly to remove dust, burrs, and oil, ensuring that the joint surfaces are clean;

[0070] Wing box and upper plate docking: Align the wing box support partition 20-22 with the fuselage upper plate 16 at the wing, so that the protrusion of the wing box support partition 20-22 passes vertically through the preset hole of the fuselage upper plate 16 at the wing, and ensure that the bottom of the support partition is completely in contact with the upper surface of the fuselage upper plate.

[0071] Support beam assembly: Embed the connecting support beam 25 into the slot of the wing box support partition 20-22, temporarily fix it with a clamp, and evenly apply epoxy resin adhesive to the mating surface, and let it stand until the adhesive is completely cured.

[0072] Inner and outer wing rib installation: Arrange the inner and outer wing ribs 20 and 21 of the wing box boundary symmetrically on both sides of the fuselage side panel 18, adjust their position so that they fit tightly against the edge of the fuselage side panel 18 and the fuselage top panel 16 at the wing, and then temporarily fix them with clamps again.

[0073] Pin fixing and inspection: Press the bamboo pins vertically into the slots of the 16 bosses on the fuselage plate at the wing, and tap the top of the pins lightly to ensure they are in place; after assembly, check the connection status of each component, requiring no looseness and no obvious gaps.

[0074] As shown in Figures 6(a) and 6(b), the present invention provides a connection structure between the tail wing 10 and the fuselage 2 of a bamboo fixed-wing UAV, the specific implementation of which is as follows:

[0075] The lower bosses of the two tail fin positioning support plates 30 pass through and are fixed to the preset holes on the fuselage upper plate 23. The middle part of the tail fin positioning support plate 30 is aligned with the horizontal stabilizer main beam 28, and its upper end is pre-aligned with the corresponding installation positions of the horizontal stabilizer upper plate 26 and the vertical stabilizer root wing rib 31. Its end boss is pre-aligned with the slots provided on the rear wall of the horizontal stabilizer and then installed.

[0076] The end of the vertical tail main beam 29 is pre-machined with slots. The slots at the end of the vertical tail main beam 29 are then fitted with pre-set connection points on the tail fin positioning support plate 30. This connection, together with the connection in the previous step, effectively disperses and transfers the load from the tail fin main beam to the horizontal stabilizer rear wall 32 and the fuselage structure further forward.

[0077] The horizontal tail rear wall 32 and the vertical tail main beam 29 are precisely fitted with the rear end boss of the tail fin positioning support plate 30. This boss-slot fit constitutes the main shear and bearing interface, used to directly transfer the load of the vertical tail.

[0078] After the upper boss of the tail fin positioning support plate 30 passes through the horizontal stabilizer upper plate 26 and the vertical stabilizer root rib 31 in sequence, bamboo pins are used to pass through the preset pin holes for lateral limiting and fixing to resist the pulling force during flight.

[0079] After the upper boss of the tail fin positioning support plate 30 passes through the horizontal stabilizer upper plate 26 and the vertical stabilizer root rib 31 in sequence, bamboo pins are used to pass through the preset pin holes for lateral limiting and fixing to resist the pulling force during flight.

[0080] After the lower boss of the tail fin positioning support plate 30 passes through the fuselage plate, it is also laterally fixed using bamboo pins. This double pin fixing mechanism together ensures the integrity, stability, and reliability of the tail fin assembly under aerodynamic loads.

[0081] Working principle:

[0082] The bamboo fixed-wing UAV wing box and fuselage plate connection structure of the present invention achieves stable connection, efficient force transmission and anti-slip positioning between the wing box and fuselage through the structural cooperation and material properties of each component. The specific working principle is as follows:

[0083] During UAV flight, the lift, drag, and tensile / compressive forces generated by the loads on the wing box are transmitted to the boss at its bottom through the wing box support partitions 20-22. The rectangular slots on the bosses precisely engage with the connecting support beams 25, allowing the tensile / compressive forces to be directly transmitted to the connecting support beams 25, which are evenly distributed along the length of the fuselage upper plate 16 at the wing. The connecting support beams 25 form a stable beam-type support structure, dispersing the concentrated tensile / compressive forces to the bottom of the entire fuselage upper plate and the fuselage support partitions at the wing box. Simultaneously, the close fit between the support beams and the slots, along with the fixing effect of the adhesive, avoids localized stress concentration, significantly improving the fatigue resistance and load-bearing capacity of the connection points, and preventing structural loosening or fracture caused by tensile / compressive loads.

[0084] The connecting support beam 25 is made of bamboo fiber reinforced composite material and is evenly distributed along the length of the fuselage plate 16 at the wing. The cross-section of each connecting support beam 25 is rectangular. The connecting support beam 25 is horizontally embedded in the slot of the boss of the wing box support partition 20-22, and both ends are fixedly connected to the fuselage side plate 18 to expand the tensile and compressive stress area of ​​the connection part.

[0085] The shear force generated by changes in flight attitude and airflow disturbance at the junction of the fuselage and wing box is mainly borne by the inner and outer wing ribs of the wing box boundary. This structure is formed by combining two layers of bamboo wing ribs and fuselage side panels 18 through a pre-compression process, creating a shear stress surface that is twice that of a single wing rib. This allows the shear force to be transmitted to the fuselage simultaneously through the inner and outer wing ribs, effectively dispersing the shear stress, avoiding overload damage to a single stress surface, and ensuring the structural stability of the junction.

[0086] After the bamboo pins are pressed into the slots, they form a rigid positioning. The tight fit between the pins and the slots restricts the lateral sliding of the double-layered wing ribs along the width of the fuselage at the wing box boundary. At the same time, the cooperation between the bamboo pins, the bosses, and the wing ribs locks the relative position of the wing box and the fuselage top plate 16 at the wing, avoiding the connection accuracy deviation caused by flight vibration and airflow impact, ensuring that the wing box always maintains the correct installation posture, and guaranteeing flight stability.

[0087] The connection structure of this invention achieves a reliable connection between the machine head and the fuselage through the synergistic effect of "internal limiting + external reinforcement + stress dispersion". The specific working principle is as follows:

[0088] During flight, the junction between the nose 1 and the fuselage 2 must withstand various forces, including aerodynamic loads, inertial loads, longitudinal tension, lateral shear force, and torsional moment. Internally, the front fuselage support bulkhead 14 and the rear nose support bulkhead 9 receive the external fasteners 10 through slots, distributing the concentrated load transmitted by the bamboo pins to the entire bulkhead, and then transmitting it to the main structure of the fuselage 2 and nose 1 through the bulkhead, thus avoiding load concentration in a single slot or joint edge. Externally, the symmetrically distributed pairs of external fasteners 10 increase the contact area of ​​the load-bearing components, dispersing local stress to a wider area of ​​the side plates and bottom plates. At the same time, the high specific strength of bamboo fiber reinforced composite materials is utilized to achieve a balance between lightweight and load-bearing capacity.

[0089] The interference fit between the bamboo pins and the slots and through holes of each component creates an axial preload. Combined with the anti-slip texture on the pin surface, this effectively limits the relative sliding between the nose 1 and the fuselage 2. The surface contact structure of the nose plate 8 and the extended portion of the fuselage plate 13 at the nose further limits longitudinal slippage. The symmetrical arrangement of the fasteners 10 suppresses lateral offset and torsion, ensuring stable connection accuracy during flight and preventing structural loosening or uneven load distribution caused by slippage.

[0090] All components are integrally molded from bamboo fiber reinforced composite material, with consistent material properties, avoiding loosening of connections caused by differences in thermal expansion and contraction between different materials; the fastener 10 not only serves as reinforcement, but also protects the connection between the slot and the bamboo pin, reducing the erosion of the connection by airflow and moisture; the extended bosses of the front support partition 14 and the rear support partition 9 of the machine body, along with the superimposed design of the upper plate 13 and the upper plate 8 of the machine head, enhance the bending resistance of the top connection, forming a three-dimensional protection with the fixing structure of the side plate and the bottom plate, comprehensively improving the overall rigidity and torsional strength of the connection.

[0091] The working principle of this invention is based on a core objective: to construct an efficient, stable, and multi-path payload transfer channel for the vertical tail of an unmanned aerial vehicle (UAV). Its working process is as follows:

[0092] When the UAV is in flight, the vertical tail mainly bears the aerodynamic forces from the yaw direction, which manifest as lateral forces, torque (bending moment about the vertical axis), and shear forces. These loads first act on the vertical tail skin and vertical tail ribs, and then quickly converge to the vertical tail main beam 29, which is the main longitudinal load-bearing component.

[0093] The slots in the root ribs 31 of the vertical tail precisely engage with the bosses on the upper part of the positioning support plate, forming the main bearing and shear interface. At this point, most of the bending moment (manifested as a pair of tensile and compressive couples) and shear force on the main beam are directly transmitted to the positioning support plate through this boss.

[0094] The vertical tail main beam 29 is the core of vertical load bearing. It adopts a through-type connection to lock the upper plate of the horizontal tail and the upper plate of the fuselage tail, and transmits the lateral aerodynamic load to the main frame of the fuselage and the horizontal tail in a force rectangular manner, so as to realize the rapid dispersion of vertical and horizontal loads and suppress stress concentration at the connection point.

[0095] The tail fin positioning support plate 30 serves as a lateral positioning and reinforcement unit. Its rear end boss, horizontal tail rear wall 32, and vertical tail main beam 29 end slot form a mortise and tenon locking structure. When the vertical tail is subjected to swing or torsion, the load is borne by the main beam, support plate, and horizontal tail rear wall together. The lateral stiffness of the support plate offsets the torsional moment, improving the tail fin assembly's anti-distortion capability and maintaining aerodynamic shape accuracy.

[0096] The transverse pin passes through the fuselage tail section 33 and the end of the main beam, forming a root anchoring constraint and locking the vertical degree of freedom of the tail. When the main beam is subjected to aerodynamic bending moment, the pin transmits the shear load to the overall fuselage structure through the section, and uses the overall rigidity of the fuselage to disperse the root concentrated stress, ensuring the reliability of the tail root structure under high speed and high maneuver conditions.

[0097] The tail fin positioning support plate 30, acting as a core "force flow converter," distributes the received load in two key directions through its unique structural design: the connection between the tail fin positioning support plate 30 and the rear of the horizontal stabilizer directly transfers a portion of the load (especially tension and compression) to the rear wall 32 of the horizontal stabilizer, from which it is then distributed to the overall structure of the horizontal stabilizer; the middle part of the tail fin positioning support plate 30 connects to the main beam 28 of the horizontal stabilizer, with its lower boss passing through the upper plate of the fuselage. Through these two connections, the remaining load (especially vertical shear force and part of the bending moment) is efficiently transferred to the main load-bearing structure of the UAV fuselage.

[0098] To ensure absolute reliability of the connection under severe alternating aerodynamic loads, the system is equipped with dual pull-out protection: bamboo pins passing through the bosses on the upper and lower positioning support plates provide crucial lateral restraint, effectively resisting the pull-out tendency that may occur at all connection nodes during flight and preventing structural loosening; the fit between all bosses and corresponding slots constitutes a mechanical interlock, limiting unintended displacement in all directions.

[0099] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A connection structure for a bamboo-made fixed-wing unmanned aerial vehicle, characterized in that, The bamboo fixed-wing UAV includes a nose (1), a fuselage (2), a wing (3) and a tail (10); the nose (1) is fixedly connected to the fuselage (2), the wing (3) is fixedly connected to the fuselage (2), and the tail (10) is fixedly connected to the fuselage (2).

2. The connection structure for a bamboo fixed-wing UAV according to claim 1, characterized in that, The fixed connection is a bamboo pin connection, and the bamboo pin is made of bamboo fiber reinforced composite material.

3. The connection structure for a bamboo fixed-wing UAV according to claim 1, characterized in that, The nose (1) includes a fuselage upper plate (8), a nose side plate (11), a nose bottom plate (12), a nose tail support plate (9), and an external fastener (10); the fuselage (2) includes a fuselage upper plate (13) at the nose, a fuselage front support plate (14), a fuselage bottom plate (15), a fuselage upper plate (16) at the wing, a fuselage support plate (17) at the wing box, a fuselage side plate (18), a fuselage upper plate (19) at the tail wing, and a fuselage tail end plate (33); The tail end support partition (9), the front end support partition (14) and the tail end partition (33) of the fuselage are parallel and upright in sequence, with protrusions distributed around them; the end of the upper plate (8) of the fuselage is placed above the front end of the upper plate (13) at the head, and the end of the upper plate (8) and the front end of the upper plate (13) at the head have two rows of overlapping slots. The two rows of slots are respectively matched with the bosses at the upper end of the head tail support partition (9) and the front support partition (14) of the body, so as to achieve a fixed connection; a boss is provided at the part where the side of the upper plate (8) of the body contacts the side plate (11) of the head; a boss is provided at the part where the side of the upper plate (13) of the head contacts the side plate (18) of the body. The machine head base plate (12) is placed below the machine head tail end support partition (9); the machine head base plate (12) has slots distributed at its end, which match the boss at the lower end of the machine head tail end support partition (9), thereby realizing the connection between the machine head tail end support partition and the machine head base plate; the machine head base plate (12) has a boss at the part where it contacts the machine head side plate (11); The machine head side plate (11) is parallel and upright, and is distributed at the left and right ends of the machine head tail support partition (9); the machine head side plate (11) has grooves around its perimeter, which match the bosses at the contact points of the machine body upper plate (8), the machine head bottom plate (12) and the machine head tail support partition (9), thereby achieving a fixed connection. The fuselage base plate (15) is located below the front support partition (14) and the rear partition (33) of the fuselage; the front and rear ends of the fuselage base plate (15) are provided with slots, which match the bosses at the lower ends of the front support partition (14) and the rear partition (33) of the fuselage, thereby realizing the connection between the fuselage base plate, the front support partition and the rear partition; the side of the fuselage base plate (15) that contacts the fuselage side plate (18) is provided with a boss; The fuselage side plates (18) are parallel and upright, and are distributed at the left and right ends of the front support partition (14) and the rear partition (33) of the fuselage. The fuselage side plates (18) are surrounded by slots, which are matched with the bosses at the contact parts of the upper plate (13) of the fuselage head, the bottom plate (15) of the fuselage, the front support partition (14) of the fuselage and the rear partition (33) of the fuselage, thereby achieving a fixed connection. The external fastener (10) has openings at both ends. One end of the opening overlaps with the slots at the end of the head side plate (11) and the end of the head bottom plate (12); the other end of the opening overlaps with the slots at the front end of the body side plate (18) and the front end of the body bottom plate (15). The bamboo pin passes through the external fastener (10), the head side plate (11) and the body side plate (18) in sequence to connect the head side plate (11) and the body side plate (18). The bamboo pin passes through the external fastener (10), the head bottom plate (12) and the body bottom plate (15) in sequence to connect the head bottom plate (12) and the body bottom plate (15). The front end of the fuselage upper plate (16) at the wing is connected to the fuselage upper plate (13) at the nose, the rear end is connected to the fuselage upper plate (19) at the tail, and the left and right sides are connected to the fuselage side plates (18). The fuselage support partition (17) at the wing box and the fuselage front support partition (14) are parallel. The upper end of the fuselage support partition (17) at the wing box is connected to the fuselage upper plate (16) at the wing, the lower end is connected to the fuselage bottom plate (15), and the left and right sides are fixedly connected to the fuselage side plates (18). The fuselage support partition (17) at the wing box is used to support the fuselage (2).

4. The connection structure for a bamboo fixed-wing UAV according to claim 3, characterized in that, The external fastener (10) consists of two square plates. The external fastener (10) is placed on the inner and outer sides of the head base plate (12), the body base plate (15), the head side plate (11), and the body side plate (18). Each square plate has two openings, which are symmetrically positioned to evenly distribute structural stress and enhance connection strength.

5. The connection structure for a bamboo fixed-wing UAV according to claim 1, characterized in that, The wing (3) includes a wing box (6) and a wing surface (7); the wing box (6) includes a wing box support partition (20), a wing box support partition (21), a wing box support partition (22), an inner wing rib (23) of the wing box boundary, an outer wing rib (24) of the wing box boundary, and a connecting support beam (25); The wing box support partition (20), wing box support partition (21) and wing box support partition (22) are all square plates with a boss at the bottom and a slot on the boss; at the same time, there are bosses at the left and right ends; the wing box support partition (20), wing box support partition (21) and wing box support partition (22) are evenly parallel and upright above the fuselage top plate (16) at the wing; The fuselage upper plate (16) at the wing is provided with slots at the contact points with the wing box support partition (20), wing box support partition (21) and wing box support partition (22). The slots are connected with the bosses with slots, thereby realizing the initial connection between the fuselage upper plate (16) at the wing and the wing box support partition (20), wing box support partition (21) and wing box support partition (22). The fuselage upper plate (16) at the wing is provided with bosses on the left and right sides, and the bosses are provided with slots. The inner wing rib (23) and outer wing rib (24) of the wing box boundary are respectively placed on the inner and outer sides of the fuselage side plate (18), and are provided with horizontal and vertical slots. The vertical slots are matched with the bosses at the left and right ends of the wing box support partition (20), wing box support partition (21) and wing box support partition (22), respectively. The horizontal slots are matched with the bosses on the left and right sides of the fuselage upper plate (16) at the wing. The bosses with slots on the left and right sides of the fuselage upper plate (16) at the wing pass through the inner wing rib (23), fuselage side plate (18) and outer wing rib (24) of the wing box boundary in turn. The slots on the bosses are matched with bamboo pins to achieve a stable connection between the fuselage upper plate (16) at the wing and the fuselage side plate (18). The connecting support beam (25) is located at the bottom of the fuselage plate (16) at the wing, and passes laterally through the slot at the top of the fuselage support partition (17) at the wing box, the slot at the bottom of the boss of the wing box support partition (20), the slot at the bottom of the boss of the wing box support partition (21), and the slot at the bottom of the boss of the wing box support partition (22); thereby achieving a stable connection between the fuselage plate (16) at the wing, the fuselage support partition (17) at the wing box, the wing box support partition (20), the wing box support partition (21), and the wing box support partition (22).

6. The connection structure for a bamboo fixed-wing UAV according to claim 1, characterized in that, The tail fin (10) includes a vertical tail (4) and a horizontal tail (5), the vertical tail (4) and the horizontal tail (5) being fixedly connected; the horizontal tail (5) includes a tail fin positioning support plate (30), a horizontal tail upper plate (26), a horizontal tail side plate (27), a horizontal tail main beam (28), and a horizontal tail rear wall (32); the vertical tail (4) includes a vertical tail root wing rib (31) and a vertical tail main beam (29). The tail fin positioning support plate (30) is perpendicular to the upper plate (26) of the horizontal stabilizer and the upper plate (19) of the fuselage at the tail fin, and the side plate (27) of the horizontal stabilizer is parallel to the tail fin positioning support plate (30). The tail fin positioning support plate (30) has a perforated boss at both the upper and lower ends, a through hole in the middle, and a groove at the rear end. The upper boss matches the slot in the middle of the horizontal tail upper plate (26) and the slot in the vertical tail root wing rib (31). The lower boss matches the slot on the fuselage upper plate (19) at the tail fin. The size of the through hole in the middle is the same as the cross-sectional size of the horizontal tail main beam (28). The protrusion formed by the groove at the rear end matches the slot in the horizontal tail rear wall (32), and the lower boss at the rear end matches the slot at the end of the vertical tail main beam (29). The horizontal tail side plate (27) has slots at both the top and bottom, and a through hole in the middle. The upper slot matches the boss on the side of the horizontal tail upper plate (26). The lower slot matches the boss with slots on both sides of the upper plate (19) of the tail fin. The through hole in the middle has the same cross-sectional dimensions as the horizontal tail main beam (28) and the horizontal tail rear wall (32). The bosses on both sides of the upper plate (19) of the tail fin pass through the horizontal tail side plate (27) and are fixedly connected to the slots on the bosses by bamboo pins. The tail beam (29) is a box beam with the end of the rear plate extending and having a slot; the tail beam (29) is located vertically in the middle of the tail root wing rib (31), the end of the tail beam (29) extends and has a slot, and the middle of the tail root wing rib (31) has a through hole with the same cross-sectional size as the tail beam (29). The upper boss of the tail fin positioning support plate (30) passes through the corresponding slots on the upper plate of the horizontal stabilizer (26) and the root wing rib (31) of the vertical stabilizer. A bamboo pin then fixes the upper boss to the slot, thus achieving a fixed connection between the tail fin positioning support plate (30) and the upper plate of the horizontal stabilizer (26) and the root wing rib (31) of the vertical stabilizer. The lower boss mates with the slot on the fuselage upper plate (19) at the tail fin, and a bamboo pin then fixes the lower boss to the slot, thus achieving a fixed connection between the tail fin and the fuselage upper plate (26) and the root wing rib (31). The body plate (19) is fixedly connected to the tail fin positioning support plate (30); the horizontal tail main beam (28) and the horizontal tail rear wall (32) pass through the through holes in the middle of the horizontal tail side plate (27), the tail fin positioning support plate (30) and the horizontal tail side plate (27) respectively, so as to realize the mutual connection of the tail fin positioning support plate, the horizontal tail main beam and the horizontal tail rear wall; the horizontal tail side plate (27) is provided with slots, which are connected with the perforated bosses on both sides of the body plate (19) at the tail fin and then fixed with bamboo pins; The extended portion of the vertical tail main beam (29) passes through the slots on the upper plate (26) of the horizontal tail and the upper plate (19) of the fuselage at the tail fin in sequence; the two protrusions formed by the groove at the rear end of the tail fin positioning support plate (30) pass through the slot in the middle of the horizontal tail rear wall (32) and the slot at the extended portion of the vertical tail main beam (29) respectively, and are fixed by bamboo pins in conjunction with the slot at the extended portion of the vertical tail main beam (29), thereby making a stable connection.

7. The connection structure for a bamboo fixed-wing UAV according to claim 1, characterized in that, The nose (1), fuselage (2), wings (3) and tail (10) are all made of bamboo fiber reinforced composite material.

8. The connection structure for a bamboo fixed-wing UAV according to claim 5, characterized in that, The outer wing rib (24) and the inner wing rib (23) of the wing box boundary are both composed of two parallel bamboo boards, which are made of bamboo fiber reinforced composite material.

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