Deformable empennage applied to bionic aircraft

Abstract

The invention discloses a deformable empennage applied to a bionic aircraft, and relates to the technical field of bionic flying robots. Through efficient cooperation of five-degree-of-freedom motion of the empennage and deformation motion of the wings, the maneuverability and adaptability of the aircraft are remarkably improved. The bionic aircraft comprises a motor, a fuselage, a deformation wing, an empennage and an empennage deformation driving mechanism. And flexible switching among a horizontal tail state, a positive V tail state and an inverted V tail state can be realized. When the state is switched to the positive V tail state, parasitic resistance can be effectively reduced, wingtip vortex interference is reduced, and the aerodynamic efficiency of the cruising stage is improved; when the inverted V-tail state is switched, the influence of wing wake flow can be avoided, the aerodynamic stability is obviously enhanced under the working condition of a large angle of attack, and the stall risk is effectively inhibited; and when the horizontal tail state is switched, aerodynamic lift force distribution in the low-speed stage can be optimized, and the aerodynamic response of take-off and landing control is improved. The flexible switching of the empennage among the three states provides better pneumatic suitability for the aircraft in different flight stages and task scenes.

Description

Technical Field

[0001] This invention relates to the field of biomimetic flying robot technology, and in particular to a design of a tail fin folding and deformation mechanism for biomimetic flying vehicles. Background Technology

[0002] Existing technologies take into account that birds achieve high maneuverability and stability by changing the shape and angle of their wings and tails, a characteristic that has inspired the design of biomimetic aircraft. However, the tail structures of existing biomimetic aircraft are mostly fixed or have low degrees of freedom, making it difficult to fully simulate the complex flight postures of birds. For example, the tails in existing technologies typically use a conventional tail configuration combining horizontal and vertical tails, which has fewer degrees of freedom compared to the flexible and deformable tails of birds. This results in insufficient adaptability and maneuverability of the aircraft in complex environments. Currently, patents regarding the design of deformable tails for bird-inspired deformable aircraft also have their limitations; specifically: Chinese invention patent application CN118323441A proposes a dual-servo-controlled positive V-shaped split tail structure, which improves the flexibility and agility of flapping-wing aircraft, but its tail structure is still a fixed layout and cannot achieve multi-degree-of-freedom dynamic deformation.

[0003] Chinese invention patent applications CN120606957A and CN115214875A, respectively, design a flapping-wing aircraft with multi-degree-of-freedom tail fin cooperative motion. CN120397257A and CN120397257A also design a bio-hybrid deformable flapping-wing aircraft. The tail fin structures in these patents can achieve independent or combined control of twisting, pitching, yaw, and opening / closing movements. However, the tail fins all have a single horizontal tail shape, resulting in poor lateral stability under gusts, high control difficulty, and poor environmental adaptability.

[0004] Chinese invention patent application CN120503955A discloses a novel bird-inspired tail fin multi-degree-of-freedom platform capable of controlling the heading, roll, and pitch directions, and also able to change the area of ​​the tail fin assembly. However, the pitch and roll rotations are limited by the mechanism design and cannot be controlled independently.

[0005] In summary, while existing biomimetic aircraft tail structures possess a certain degree of deformability, they still exhibit significant shortcomings in multi-degree-of-freedom tail design, resistance to gusts, and the coupling deformation of multi-degree-of-freedom tail components. Currently, most biomimetic aircraft-related patents focus on improving the pitch, twist, and unfolding mechanisms of the tail, without addressing tail folding and deformation designs. Summary of the Invention

[0006] To address the above problems, this invention proposes a deformable tail fin for biomimetic aircraft. Through the efficient coordination of the five-degree-of-freedom motion of the tail fin and the deformable wing, the maneuverability and adaptability of the aircraft are significantly improved.

[0007] The technical solution of the present invention is as follows: the bionic aircraft includes a drive motor 1, a fuselage 2, a tail fin 3, a tail fin deformation drive mechanism 4, and a deformable wing 5. The drive motor 1, the deformable wing 5, and the tail fin deformation drive mechanism 4 are fixedly installed in the fuselage 2. The tail fin deformation drive mechanism 4 is connected to the tail fin 3 and is used to drive the tail fin 3 to perform twisting, offsetting, pitching, unfolding, and folding actions. The tail fin deformation drive mechanism 4 includes a torsion servo 401, a torsion servo rocker arm 402, a torsion coupling 403, a connecting servo 404, a square hollow carbon rod 419, an omnidirectional head fuselage connector 424, and an omnidirectional joint 426. The torsion servo 401 is fixedly installed in the fuselage 2 and is used to drive the torsion servo rocker arm 402 to reciprocate. The torsion servo rocker arm 402, the torsion coupling 403, the connecting servo 404, the square hollow carbon rod 419, and the omnidirectional head fuselage connector 424 are fixedly connected from front to back. The rod 419 is rotatably mounted at the rear of the fuselage 2; the front of the tail fin 3 has a C-shaped tail fin frame 301, and the omnidirectional joint 426 is installed between the tail fin frame 301 and the omnidirectional head fuselage connector 424, so that the omnidirectional head fuselage connector 424 can drive the tail fin frame 301 to twist, while allowing the tail fin frame 301 to flip up and down and deflect left and right; the servo 404 is equipped with a pitch drive mechanism for driving the tail fin frame 301 to flip up and down and an offset drive mechanism for driving the tail fin frame 301 to deflect left and right. The tail wing 3 includes a tail wing frame 301, a left deformable tail wing clamp 306, a right deformable tail wing clamp 314, two sets of tail feather connectors, and feathers fixedly connected to the tail feather connectors. The left deformable tail wing clamp 306 and the right deformable tail wing clamp 314 are rotatably connected by a pivot, and the pivot is fixedly installed behind the tail wing frame 301. A folding drive mechanism for driving the left deformable tail wing clamp 306 and the right deformable tail wing clamp 314 to flip up and down synchronously is also installed on the tail wing frame 301. Two sets of tail feather connectors are respectively installed in the left deformable tail fin clamp 306 and the right deformable tail fin clamp 314. Each set of tail feather connectors includes an inner tail feather connector 312, a middle tail feather connector 311, and an outer tail feather connector 308. The two sets of tail feather connectors are connected by an elastic rope 313. The two inner tail feather connectors 312 are fixedly connected to the left deformable tail fin clamp 306 and the right deformable tail fin clamp 314 respectively. The two middle tail feather connectors 311 are rotatably connected to the left deformable tail fin clamp 306 and the right deformable tail fin clamp 314 respectively. The two outer tail feather connectors 308 are rotatably connected to the left deformable tail fin clamp 306 and the right deformable tail fin clamp 314 respectively. The connecting rudder 404 is also equipped with a first opening and closing drive mechanism and a second opening and closing drive mechanism for driving the two outer tail feather connectors 308 to open or close synchronously.

[0008] Furthermore, the omnidirectional joint 426 is rotatably connected to the omnidirectional head body connector 424 via a horizontal pin 425, and is rotatably connected to the tail fin frame 301 via a vertical bolt 413.

[0009] Furthermore, the pitch drive mechanism includes a pitch servo 415, a pitch servo rocker arm 414, a pitch lever 410, and a pitch ball joint lever 412; The pitch servo 415 is fixedly installed in the fuselage 2 and is used to drive the pitch servo rocker arm 414 to swing back and forth. One end of the pitch lever 410 is hinged to the pitch servo rocker arm 414, and the other end is fixedly connected to the pitch ball joint lever 412. The pitch ball joint lever 412 is hinged to the vertical bolt 413 through a ball joint.

[0010] Furthermore, the offset drive mechanism includes an offset servo motor 406, an offset servo motor rocker arm 405, an offset tie rod 409, and an offset ball joint tie rod 411; The offset servo 406 is fixedly installed in the fuselage 2 and is used to drive the offset servo rocker arm 405 to swing back and forth. One end of the offset tie rod 409 is hinged to the offset servo rocker arm 405, and the other end is fixedly connected to the offset ball joint tie rod 411. The offset ball joint tie rod 411 is hinged to the tail fin frame 301 through a ball joint.

[0011] Furthermore, a diagonal support arm is fixedly installed on one side of the tail fin frame 301, and the offset ball joint rod 411 is hinged to the diagonal support arm through a ball joint.

[0012] Furthermore, the folding drive structure includes a folding servo motor 302, a gear 303, a rack 304, a left connecting rod 305, a right connecting rod 315, and a guide shaft 316; The folding servo 302 is fixedly mounted on the tail fin frame 301. The center of the gear 303 is fixedly mounted on the output of the folding servo 302. A vertically arranged guide shaft 316 is also fixedly mounted on the tail fin frame 301. The rack 304 is fitted on the guide shaft 316 and meshes with the gear 303. The bottom end of the left connecting rod 305 and the bottom end of the right connecting rod 315 are simultaneously hinged to the bottom end of the rack 304. The top ends of the left connecting rod 305 and the right connecting rod 315 are respectively hinged to the middle parts of the left deformable tail fin clamp 306 and the right deformable tail fin clamp 314.

[0013] Furthermore, the first deployable drive mechanism includes a first deployable servo motor 416 and a first deployable servo motor rocker arm 417. The first deployable servo motor 416 is fixedly installed in the fuselage 2 and is used to drive the first deployable servo motor rocker arm 417 to swing back and forth. The second deployable drive mechanism includes a second deployable servo motor 408 and a second deployable servo motor rocker arm 407. The second deployable servo motor 408 is fixedly installed in the fuselage 2 and is used to drive the second deployable servo motor rocker arm 407 to swing back and forth. The first and second servo rocker arms 417 and 407 are connected to two outer tail feather connectors 308 by two inelastic ropes 418 respectively. The two outer tail feather connectors 308 are opened synchronously by pulling the two inelastic ropes 418.

[0014] Furthermore, a fixing pin 423 is fixedly provided on the center plane of the connecting rudder 404, and pulleys 307 are respectively installed on the left deformable tail fin clamp 306 and the right deformable tail fin clamp 314. The inelastic rope 418 passes around the fixing pin 423 and the pulleys 307.

[0015] Compared with the prior art, the tail fin of the present invention not only has four degrees of freedom of motion capabilities (pitch, roll, yaw, and unfold), but also adds a folding function, enabling asymmetrical adjustment of the tail fin area and flexible switching between horizontal and V-tail states. The beneficial effects of the present invention are as follows: I. The folding and deformation of the tail fin enables the aircraft to possess different flight modes: the horizontal tail configuration is suitable for high-speed cruise, with low aerodynamic drag and good pitch stability and controllability; the folded and bent V-tail configuration enhances the aircraft's directional control and maneuverability, making it perform well in complex scenarios such as low-speed flight, encountering crosswinds, airflow disturbances, and thrust asymmetry; the folded and bent inverted V-tail configuration features optimized performance at high angles of attack. As the angle of attack increases, the inverted V-tail faces downwards and leaves the wing wake, enhancing the aircraft's stability at high angles of attack. Through dynamic adjustment of the aerodynamic configuration, the folding and deformation of the tail fin achieves a balance between aerodynamic performance and controllability throughout the entire flight envelope without adding additional aerodynamic components.

[0016] Second, it can not only achieve control in three directions: heading, roll, and pitch, but also introduces a dynamic tail fin assembly area adjustment function, which enables the tail fin assembly to be adjusted in real time according to the flight status, thereby improving the flexibility and adaptability of the tail fin assembly movement, and enabling the new bird-inspired tail fin multi-degree-of-freedom platform to better simulate the movement characteristics of the tail of organisms in nature. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure (excluding the top cover of the fuselage); Figure 2 This is a schematic diagram of the tail fin's twist, pitch, unfold, and offset mechanisms. Figure 3 This is a schematic diagram of the tail fin folding mechanism; Figure 4 It is a simple tail wing folding mechanism Figure 1 ; Figure 5 It is a simple tail wing folding mechanism Figure 2 ; Figure 6 It is a simple tail wing folding mechanism Figure 3 ; Figure 7 The left view of the tail fin shows a partial view of the gears and racks meshing; Figure 8 This is a schematic diagram of the cross-sectional structure of the deformable tail fin clamp; Figure 9 This is a top view of the tail fin.

[0018] In the diagram, 1 is the motor, 2 is the fuselage, 3 is the tail fin, 4 is the tail fin morphing drive mechanism, and 5 is the morphing wing; l1 is the first sideline, and l2 is the second sideline. 301 is the tail fin frame, 302 is the folding servo, 303 is the gear, 304 is the rack, 305 is the left connecting rod, 306 is the left deformable tail fin clamp, 307 is the pulley, 308 is the outer tail feather connector, 309 is the thin carbon rod, 310 is the first outer feather, 311 is the middle tail feather connector, 312 is the inner tail feather connector, 313 is the elastic rope, 314 is the right deformable tail fin clamp, 315 is the right connecting rod, 316 is the guide shaft, 317 is the first middle feather, 318 is the first inner feather, 319 is the second inner feather, 320 is the second middle feather, 321 is the second outer feather, 322 is the square carbon rod, 323 is the round carbon rod, and 324 is the flexible film. 401 is a torsion servo, 402 is a torsion servo rocker arm, 403 is a torsion coupling, 404 is a connecting servo, 405 is a offset servo rocker arm, 406 is an offset servo, 407 is a second deployable servo rocker arm, 408 is a second deployable servo, 409 is an offset lever, 410 is a pitch lever, 411 is an offset ball joint lever, 412 is a pitch ball joint lever, 413 is a vertical bolt, 414 is a pitch servo rocker arm, 415 is a pitch servo, 416 is a first deployable servo, 417 is a first deployable servo rocker arm, 418 is a non-elastic rope, 419 is a square hollow carbon rod, 420 is a rotary shaft support base, 421 is a movable support, 422 is a rotary shaft support top cover, 423 is a fixing pin, 424 is an omnidirectional head body connector, 425 is a horizontal pin, and 426 is an omnidirectional joint. Detailed Implementation

[0019] To clearly illustrate the technical features of the present invention, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0020] like Figure 1 As shown, the biomimetic aircraft comprises a motor 1, a fuselage 2, a tail fin 3, a tail fin deformation drive mechanism 4, and a deformable wing 5. Both the wing deformation mechanism and the tail fin deformation mechanism are mounted on the fuselage. The motor and propellers serve as the aircraft's power source, and the flight state is altered through the wing and tail fin deformation mechanisms. The tail fin proposed in this invention possesses multi-degree-of-freedom motion capabilities, including twisting, deflection, pitching, and unfolding, enabling asymmetrical changes in tail fin area and flexible switching between horizontal and V-tail states. The deformable wing of the biomimetic aircraft includes two deformable joints, allowing for forward and backward sweeping, and the two wings can undergo asymmetrical twisting.

[0021] In one specific implementation, an X2216KV1250 motor, coupled with a 9047 propeller (not shown in the figure) mounted on the motor's output shaft, serves as the power source. Initially, the tail fin is deployed, increasing its area. When the motor reaches maximum speed, the aircraft is launched, and the tail fin is adjusted downwards to bring the aircraft nose-down until the fuselage is horizontal, reducing the motor speed and entering loitering mode. The deformable wings on both sides asymmetrically sweep back, generating a roll moment, causing the aircraft to turn. When there is significant gust interference, the tail fin folds upwards into a V-shape, while simultaneously twisting to adjust the heading. The wings twist asymmetrically to resist the roll caused by gusts, maintaining the fuselage level. As the aircraft descends and dives, the tail fins fold together, reducing its area, and both wings sweep back simultaneously to reduce drag and rapidly descend. After descending to a certain altitude, the tail fins pitch up, bringing the fuselage closer to horizontal, reducing the speed, and finally landing.

[0022] This design enables flexible switching between horizontal tail, upright V-tail, and inverted V-tail configurations. The horizontal tail configuration provides excellent pitch stability and low drag during high-speed cruise, effectively reducing energy consumption and improving flight efficiency. Switching to the V-tail configuration significantly enhances directional control and maneuverability during low-speed flight, maneuvering, or specific mission scenarios, facilitating the execution of complex maneuvers such as rapid turns and rolls. The flexible switching of the tail fin between these three configurations ensures the aircraft maintains superior flight performance across different flight phases and mission scenarios.

[0023] The following explains the tail fin's degrees of freedom, mechanism, and effects: Tail wing and drive mechanism such as Figure 2 , Figure 3 As shown.

[0024] The pitch of the tail fin allows the aircraft to tilt up and down, changing its longitudinal attitude. This is achieved as follows: a pitch servo 415 is fixed to a connecting servo 404. The pitch servo 415 drives the pitch servo rocker arm 414 to rotate counterclockwise, which in turn pushes the pitch lever 410. The pitch lever 410 and the pitch ball joint 412 are connected by threads. The pitch ball joint 412 is connected to the tail fin frame 301 by a vertical bolt 413. The pitch ball joint 412 pushes the tail fin frame 301 down, causing the entire tail fin to tilt down. Similarly, clockwise rotation of the pitch servo 415 tilts the tail fin up. The tail fin 3 is connected to the deformation mechanism 4 located in the fuselage 2 via an omnidirectional joint 426. During pitch, the tail fin's rotation axis is a horizontal pin 425 installed in the omnidirectional joint 426. The omnidirectional joint 426 is hinged to the tail fin frame 301 by a vertical bolt 413. Note that the use of a spherical pair here is mainly to avoid conflict with the offset degree of freedom.

[0025] The tail fin offset alone has little effect on changing the aircraft's attitude; it generally needs to be used in conjunction with the tail fin pitch control to manipulate the heading. The implementation is as follows: the offset servo 406 rotates the offset servo arm 405, pulling the offset lever 409. The offset lever 409 is threaded onto the offset ball joint lever 411, which is bolted to the tail fin frame 301. Clockwise rotation of the servo causes the entire tail fin to offset clockwise. The tail fin 3 is connected to the deformable mechanism 4 located in the fuselage via an omnidirectional joint 426. During offset, the tail fin's rotation axis is perpendicular to the omnidirectional joint 426, which is connected to the tail fin frame 301 via a vertical bolt 413. Note that a ball joint is used here primarily to avoid conflict with the pitch degree of freedom.

[0026] The aircraft's heading can be changed by twisting the tail fin, achieving yaw, similar to the rudder of a fixed-wing aircraft. The implementation is as follows: Twist servo 401 is fixed to the fuselage 2. Twist servo 401 controls the rotation of twist rocker arm 402, which is fixed to twist coupling 403. Twist coupling 403 is connected to servo linkage 404. Servo linkage 404 is equipped with offset servo 406, first offset servo 416, second offset servo 408, and pitch servo 415, which control offset, deployment, and pitch. When rocker arm 402 rotates, it drives offset servo 406, first offset servo 416, second offset servo 408, pitch servo 415, servo linkage 404, and twist coupling 403 to... The entire tail fin 3 rotates together. The rotating shaft support base 420, the movable support 422, and the rotating shaft support top cover 421 are all supports for the entire rotating shaft. The movable support 422, which is round and has a square hole, can rotate in the slots of the rotating shaft support top cover 421 and the rotating shaft support base 420. The shaft connecting the various components is a square hollow carbon rod 419. The square hollow carbon rod 419 passes through the square hole of the omnidirectional head fuselage connector 424 and is axially fixed by a pin. The square hollow carbon rod 419 is fixedly connected to the rudder 404.

[0027] The tail fin's deployment and closure can alter its area. When deployed, the tail fin has a larger area, making its control over the aircraft's attitude more pronounced. Closure is primarily used during the dive phase; the smaller tail fin area further reduces air resistance during the dive, increasing dive speed and effectively improving maneuverability. The implementation is as follows: a first deployment / closure servo 416 and a second deployment / closure servo 408 are fixed to a connecting servo 404. The first deployment / closure servo 416 and the second deployment / closure servo 408 respectively control the deployment and closure of the tail feathers on the left and right sides. Taking the second deploying servo 408 controlling the deployment of the corresponding tail feathers as an example, the second deploying servo 408 controls the rotation of the second deploying servo rocker arm 407. The inelastic rope 418 is wrapped around the second deploying servo rocker arm 407. The inelastic rope 418 passes around the fixing pin 423 located in the center plane of the connecting servo 404, passes through the center hole of the omnidirectional joint 426, the small hole on the upper side of the tail fin frame 301, passes around the pulley 307, and is finally tied to the outer tail feather connector 308 on the side. The inner tail feather connector 312, the middle tail feather connector 311, and the outer tail feather connector 308 are all connected as one unit by the elastic rope 313.

[0028] The tail fin includes a tail feather connector, feathers made of a flexible material or foam material, and a thin carbon rod 309. The tail feather connector has two symmetrical sets, each set of which includes an inner tail feather connector 312, a middle tail feather connector 311, and an outer tail feather connector 308. The two sets of tail feather connectors are connected by an elastic rope 313.

[0029] The second servo rocker arm 407 rotates clockwise, pulling the inelastic rope to rotate the outer tail feather connector 308, which in turn unfolds the middle tail feather connector 311 and the inner tail feather connector 312. Rotating counter-clockwise loosens the inelastic rope 418, and simultaneously, due to the action of the elastic rope 313, the tail feathers return to their original position, i.e., close.

[0030] When the second servo arm 407 rotates, the first servo arm 417 on the first servo 416 also rotates in the opposite direction, so that the two sets of tail feather connectors can be deployed or retracted in sync.

[0031] The folding tail fin is primarily used to change its configuration to adapt to different environments. It can transform from a horizontal tail configuration into an upward-folding, upright V-tail or a downward-folding, inverted V-tail. The angle between the upper planes of the two deformable tail fin clamps ranges from 151° to 198°, with extreme positions as follows: Figure 4 , Figure 5 As shown. The horizontal tail configuration provides the aircraft with good stability and low drag during high-speed cruise, effectively reducing energy consumption, improving flight efficiency, ensuring stable straight flight, and minimizing attitude fluctuations. Switching to the V-tail configuration significantly enhances directional control and maneuverability during low-speed flight, maneuvering, or specific mission scenarios, providing stronger aerodynamic modeling and facilitating complex maneuvers such as rapid turns and rolls. The implementation method is as follows: Figure 3 , Figure 6 and Figure 7 As shown, the tail fin frame 301 is the component connecting the tail fin to the fuselage 2, with two pivots controlling the torsion and offset of the tail fin respectively. A folding servo 302 is mounted on the tail fin frame 301, serving as the drive for the folding motion. The folding servo 302 drives the gear 303 to rotate, which in turn drives the rack 304, which meshes with the gear 303, to move up and down. The rack 304 and connecting rod 305 are connected by a revolute joint. When the rack 304 moves upward, it drives the connecting rod 305 to push the deformable tail fin clamp 306 upward. The connecting rod 305 and the deformable tail fin clamp 306 are also connected by a revolute joint. The connecting rods 305 on the left and right sides are symmetrical to the deformable tail fin clamp 306 with the rack as the central plane. When the deformable tail fin clamp 306 folds upward, the tail fin transforms from a horizontal tail state to an upward-folding V-tail. Similarly, simply changing the direction of the servo rotation achieves the transformation of the tail fin from a horizontal tail state to a downward-folding V-tail. Limited by the range of movement of rack 304 and the meshing length of gear, the tail fin angle varies from 151 to 198°.

[0032] like Figure 3 , Figure 6 and Figure 7As shown, the guide shaft 316 is a shaft fixedly connected to the tail fin frame 301, and also serves as a moving guide for the rack 304. The right deformable tail fin clamp 314 and the left deformable tail fin clamp 306 are hinged to each other and to the fixed shaft 316. The bottom ends of the left connecting rod 305 and the right connecting rod 315 are simultaneously hinged to the rack 304, and the top ends are respectively hinged to the middle parts of the left deformable tail fin clamp 306 and the right deformable tail fin clamp 314. The rack 304 is a driving component mounted on the guide shaft 316 and can slide up and down. The entire mechanism has 1 degree of freedom. BE=EF=40mm, AB=AF=21mm, AC=AG=42mm, DE=25mm. To avoid interference between the rack 304 and point A, the upper limit position of the rack 304 is limited to AD1=4.5mm. Figure 4 As shown, the included angle is 158° when the folding mechanism is at its limit position. The vertical movement of the rack 304 is driven by the gear 303 meshing with it, and the folding servo 302 controls the gear 303 to rotate within a specified range. The folding servo 302 is fixed to the tail fin frame 301. During the tail fin folding process, the positions of the folding servo 302 and the gear 303 relative to the fuselage are fixed. Due to the limited length of the rack, if the downward folding angle of the tail fin is too large, the gear will disengage from the rack, thus limiting the lower limit position of the tail fin folding. Therefore, the included angle when the downward folding mechanism is at its limit position is 198° (i.e., a minor angle of 162°). Figure 5 As shown.

[0033] Deformable tail fin clamp structure such as Figure 8 As shown, the tail feather mounting portions inside the right-side deformable tail fin clamp 314 and the left-side deformable tail fin clamp 306 are stepped, which effectively avoids interference between adjacent tail feathers in the vertical direction. It also limits the relative rotation range between the tail feathers and the deformable tail fin clamp, ensuring that excessive gaps do not form between the tail feathers during rotation. When the inner tail feathers rotate outwards, they will not exceed the area covered by the adjacent outer tail feathers, and vice versa. The tail feather arrangement is as described above. Figure 9As shown, the first inner feather 318 and the second inner feather 319 are mounted on the tail fin plane via a square carbon rod 322 and are non-rotatable. This ensures that the first side line l1 and the second side line l2 on the inner side of the tail feathers are always parallel to the rotation axis of the deformable tail fin clamp during folding (i.e., the dotted line marked in the figure). The trajectories of the first inner feather 318 and the second inner feather 319, which are most prone to interference during folding, are arcs around the rotation axis of the deformable tail fin clamp during folding. Since the two arcs do not intersect, there will be no interference. The first outer feather 310, the first intermediate feather 317, the second intermediate feather 320, and the second outer feather 321 are mounted on the deformable tail fin clamp via a circular carbon rod 323 and can rotate, enabling the tail feathers to have a degree of freedom in opening and closing. The flexible film 324 is attached to the tail feathers 318 and 319 to ensure the continuity of the plane composed of multiple tail feathers to avoid airflow separation in the gap between the tail feathers 318 and 319. At the same time, it ensures that the film can be flexibly deformed during the folding process without interference. Since the gap between the first inner feather 318 and the second inner feather 319 is small, the deformation of the film has little impact on aerodynamic performance.

[0034] There are many specific ways to implement this invention. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A deformable tail fin for use in biomimetic aircraft, characterized in that, The bionic aircraft includes a fuselage (2), a tail fin (3), a tail fin deformation drive mechanism (4), and a deformable wing (5). The tail fin deformation drive mechanism (4) is fixedly installed in the fuselage (2) and connected to the tail fin (3) to drive the tail fin (3) to perform twisting, shifting, pitching, and unfolding actions. The tail fin deformation drive mechanism (4) includes a torsion servo (401), a torsion servo rocker arm (402), a torsion coupling (403), a connecting servo (404), a square hollow carbon rod (419), an omnidirectional head fuselage connector (424), and an omnidirectional joint (426). The torsion servo (401) is fixedly installed in the fuselage (2) and is used to drive the torsion servo rocker arm (402) to reciprocate. The torsion servo rocker arm (402), the torsion coupling (403), the connecting servo (404), the square hollow carbon rod (419), and the omnidirectional head fuselage connector (424) are fixedly connected from front to back, and the square... A hollow carbon rod (419) is rotatably mounted on the rear of the fuselage (2); the front of the tail fin (3) has a C-shaped tail fin frame (301), and the omnidirectional joint (426) is mounted between the tail fin frame (301) and the omnidirectional head fuselage connector (424), so that the omnidirectional head fuselage connector (424) can drive the tail fin frame (301) to twist while allowing the tail fin frame (301) to flip up and down and deflect left and right; the rudder (404) is equipped with a pitch drive mechanism for driving the tail fin frame (301) to flip up and down and an offset drive mechanism for driving the tail fin frame (301) to deflect left and right. The tail fin (3) includes a tail fin frame (301), a left deformable tail fin clamp (306), a right deformable tail fin clamp (314), two sets of tail feather connectors and feathers fixedly connected to the tail feather connectors. The left deformable tail fin clamp (306) and the right deformable tail fin clamp (314) are rotatably connected by a pivot, and the pivot is fixedly installed behind the tail fin frame (301). A folding drive mechanism for driving the left deformable tail fin clamp (306) and the right deformable tail fin clamp (314) to flip up and down synchronously is also installed on the tail fin frame (301). Two sets of tail feather connectors are respectively installed in the left deformable tail fin clamp (306) and the right deformable tail fin clamp (314). Each set of tail feather connectors includes an inner tail feather connector (312), a middle tail feather connector (311), and an outer tail feather connector (308). The two sets of tail feather connectors are connected by an elastic rope (313). The two inner tail feather connectors (312) are fixedly connected to the left deformable tail fin clamp (306) and the right deformable tail fin clamp (314) respectively. The two middle tail feather connectors (311) are rotatably connected to the left deformable tail fin clamp (306) and the right deformable tail fin clamp (314) respectively. The two outer tail feather connectors (308) are rotatably connected to the left deformable tail fin clamp (306) and the right deformable tail fin clamp (314) respectively. The connecting rudder (404) is also equipped with a first opening and closing drive mechanism and a second opening and closing drive mechanism for respectively driving the two outer tail feather connectors (308) to open or close.

2. The deformable tail fin for a biomimetic aircraft according to claim 1, characterized in that, The omnidirectional joint (426) is rotatably connected to the omnidirectional head body connector (424) via a horizontal pin (425) and is rotatably connected to the tail fin frame (301) via a vertical bolt (413).

3. The deformable tail fin for a biomimetic aircraft according to claim 2, characterized in that, The pitch drive mechanism includes a pitch servo (415), a pitch servo rocker arm (414), a pitch lever (410), and a pitch ball joint lever (412). The pitch servo (415) is fixedly installed in the fuselage (2) and is used to drive the pitch servo rocker arm (414) to swing back and forth. One end of the pitch lever (410) is hinged to the pitch servo rocker arm (414), and the other end is fixedly connected to the pitch ball joint lever (412). The pitch ball joint lever (412) is hinged to the vertical bolt (413) through a ball joint.

4. A deformable tail fin for a biomimetic aircraft according to claim 2, characterized in that, The offset drive mechanism includes an offset servo (406), an offset servo rocker arm (405), an offset lever (409), and an offset ball joint lever (411). The offset servo (406) is fixedly installed in the fuselage (2) and is used to drive the offset servo rocker arm (405) to swing back and forth. One end of the offset tie rod (409) is hinged to the offset servo rocker arm (405), and the other end is fixedly connected to the offset ball joint tie rod (411). The offset ball joint tie rod (411) is hinged to the tail fin frame (301) through a ball joint.

5. A deformable tail fin for a biomimetic aircraft according to claim 4, characterized in that, A slanted support arm is fixedly installed on one side of the tail fin frame (301), and the offset ball joint rod (411) is hinged to the slanted support arm through a ball joint.

6. A deformable tail fin for a biomimetic aircraft according to claim 1, characterized in that, The folding drive structure includes a folding servo (302), a gear (303), a rack (304), a left connecting rod (305), a right connecting rod (315), and a guide shaft (316). The folding servo (302) is fixedly mounted on the tail wing frame (301), and the center of the gear (303) is fixedly mounted on the output of the folding servo (302). A vertically arranged guide shaft (316) is also fixedly mounted on the tail wing frame (301). The rack (304) is fitted on the guide shaft (316) and meshes with the gear (303). The bottom end of the left connecting rod (305) and the bottom end of the right connecting rod (315) are simultaneously hinged to the bottom end of the rack (304), and the top ends of the left connecting rod (305) and the right connecting rod (315) are respectively hinged to the middle of the left deformable tail wing clamp (306) and the right deformable tail wing clamp (314).

7. A deformable tail fin for a biomimetic aircraft according to claim 1, characterized in that, The first expansion and contraction drive mechanism includes a first expansion and contraction servo (416) and a first expansion and contraction servo rocker arm (417). The first expansion and contraction servo (416) is fixedly installed in the fuselage (2) and is used to drive the first expansion and contraction servo rocker arm (417) to swing back and forth. The second expansion and contraction drive mechanism includes a second expansion and contraction servo (408) and a second expansion and contraction servo rocker arm (407). The second expansion and contraction servo (408) is fixedly installed in the fuselage (2) and is used to drive the second expansion and contraction servo rocker arm (407) to swing back and forth. The first and second servo rocker arms (417) are connected to two outer tail feather connectors (308) by two inelastic ropes (418), and the two outer tail feather connectors (308) are opened synchronously by pulling the two inelastic ropes (418).

8. A deformable tail fin for a biomimetic aircraft according to claim 1, characterized in that, The connecting rudder (404) is fixedly provided with a fixing pin (423) on its central plane. The left deformable tail fin clamp (306) and the right deformable tail fin clamp (314) are respectively equipped with pulleys (307). The inelastic rope (418) passes around the fixing pin (423) and the pulleys (307).

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