Variable camber wing based on differential gear and SMA composite driving

Abstract

The application discloses a variable-camber wing driven by differential gears and SMA, and belongs to the technical field of aircrafts. The variable-camber wing comprises a plurality of independently driven variable-camber driving units arranged side by side along the span direction, and two adjacent variable-camber driving units are connected through a flexible skin. The variable-camber driving unit comprises a skin protection shell and a deformation cell body installed in the skin protection shell. A leading edge plate is fixedly installed in the skin protection shell. The leading edge plate is rotatably connected with a first rotating shaft and a second rotating shaft arranged side by side. The first rotating shaft and the second rotating shaft are fixedly connected with a first gear and a second gear that are mutually meshed. The first gear and the second gear are provided with a wire slot at the top. An SMA wire is wound and anchored in the wire slot. The first gear and the second gear can release or take in the SMA wire. A tail hook is fixedly arranged at the tail end of the deformation cell body. The SMA wire extends along the inner wall of the sliding skin to the tail hook and is anchored thereon. The application realizes smooth and high-precision adjustment of the curvature of the wing.

Description

Technical Field

[0001] This invention belongs to the field of aircraft technology, specifically relating to a variable camber wing based on differential gear and SMA composite drive. Background Technology

[0002] With the rapid development of the civilian unmanned aerial vehicle (UAV) field and the continuous expansion of future warfare concepts, higher demands are being placed on the environmental adaptability, versatility, economy, and rapid deployment of aircraft. Traditional aircraft mainly alter aerodynamic characteristics through the discrete deflection of split control surfaces such as trailing edge flaps or ailerons. This method generates significant gaps and discontinuous steps on the wing surface, leading to severe flow field stripping and induced drag, which greatly limits the lift-to-drag ratio performance of aircraft in complex aerodynamic environments. In contrast, continuously variable camber wings, by simulating the wing shape changes of biological birds, can maintain a smooth and continuous overall wing surface curvature, effectively suppressing boundary layer separation. This not only significantly improves flight efficiency but also optimizes lift distribution based on real-time flight conditions. However, existing variable camber schemes are mostly limited to the curvature changes of two-dimensional airfoil sections, making it difficult to meet the needs of coping with complex three-dimensional flow fields in real flight. Therefore, how to overcome the gaps in material compliance, load-bearing stiffness, and micro-space actuation to achieve a highly efficient and reliable three-dimensional continuously variable camber system has become a key technological bottleneck in the design of next-generation aircraft.

[0003] In the structural design of variable camber wings, the core challenge lies in balancing "deformation compliance" and "structural load-bearing capacity." Traditional elastic materials or simple linkage frames often struggle to simultaneously handle large-scale bending and torsional stiffness. Therefore, this design employs an innovative modular three-segment rigid-flexible coupled wing layout. It is particularly noteworthy that the core mechanism of this design is an independent drive unit for the entire variable wing; by combining multiple such units in parallel along the wing's spanwise direction, and integrating independent or collaborative drives, the deformation limitations of a single two-dimensional plane can be overcome, achieving complex three-dimensional wing deformation effects such as continuous spanwise torsion and asymmetric variable camber. For a single unit, a rigid thin-walled shell is used as the main load-bearing component and equipment bay at the wing's leading edge; the mid-section abandons the traditional frame, innovatively introducing a chiral hexagonal cell structure with negative Poisson's ratio characteristics. This metamaterial frame achieves high longitudinal compliance in stretching and compression through node rotation, enabling the wing to easily achieve large-curvature bending while effectively resisting torsion caused by aerodynamic loads due to its high spanwise structural stiffness. Combined with the external sliding layered skin design, the difference in inner and outer arc lengths is compensated by the micro-sliding between the skins, ensuring that the airfoil can maintain a perfect smooth laminar flow shape under any deflection angle and three-dimensional twist state, thus solving the defect of traditional flexible skin that is prone to local wrinkles that damage aerodynamic characteristics.

[0004] At the drive and transmission system level, the internal space of the leading edge of a micro-aircraft wing is extremely limited, placing extreme demands on the compactness and integration of the mechanism. Existing direct-drive motors or parallel multi-servo motor solutions are often bulky and highly susceptible to aerodynamic disturbances, resulting in "bounce" or vibration during high-speed flight. To resolve the contradiction between space and stability, this solution designs a highly integrated composite mechanical transmission chain within a rigid leading-edge nacelle. First, power is output from the servo motors, and a bevel gear mechanism completes a 90° spatial power reversal, greatly optimizing the space utilization within the narrow airfoil. This also lays the physical foundation for the high-density parallel arrangement of multiple spanwise units. Subsequently, power is transmitted to the core single-head worm gear transmission module. Utilizing the inherent small lead angle of the worm gear, the system achieves absolute self-locking at the physical level. This self-locking characteristic allows the servo motors to unload and stop after each unit reaches the target three-dimensional camber, resisting strong external aerodynamic loads without continuous energy consumption, reducing the overall system energy consumption and improving stability.

[0005] Furthermore, to address the structural internal stress problem caused by the asynchronous compensation of arc lengths on the upper and lower surfaces during wing camber changes, this mechanism integrates a four-gear differential winding system below the main shaft. This system, through the forced constraint of mechanical gears, ensures that the displacement of the upper structure during "wind release" and the lower structure during "wind retraction" are absolutely equal, achieving symmetrical reverse traction of the mid-section flexible frame and fundamentally eliminating the unexpected flight control torque offset caused by asynchronous deformation. However, pure mechanical transmission inevitably suffers from machining tolerances and backlash. Therefore, this solution creatively introduces SMA metal wire to replace the traditional traction cable in the differential cable rail. While the worm gear transmission completes high-load deformation, the phase change contraction effect of the SMA wire is triggered by controlled current heating. This not only greatly increases the deformation speed but also actively compensates for the gaps in the entire mechanical transmission chain. This rigid-flexible composite drive mode, combining the high load force of mechanical transmission with the high sensitivity of smart materials, not only constructs a high-strength solution on a single cross-section but also provides high-precision and highly coordinated technical support for the three-dimensional continuous smooth deformation of the entire wing surface. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a variable camber wing based on differential gear and SMA composite drive, which solves the problems of local surface wrinkles, precision failure of micro-mechanical gears due to backlash, and difficulty in stable self-locking under aerodynamic loads in the prior art when the variable wing undergoes continuous deformation, thereby achieving smooth and high-precision adjustment of wing curvature.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a variable camber wing based on a differential gear and SMA composite drive, comprising multiple independently driven variable camber drive units arranged side-by-side along the spanwise direction. Adjacent variable camber drive units are connected by a flexible skin. Each variable camber drive unit includes a skin protective shell, which comprises a leading edge skin, a sliding skin, and a tail metal skin sequentially and fixedly connected. Deformable cells with negative Poisson bit properties are fixedly connected to both sidewalls of the sliding skin. The tail end of each deformable cell is fixedly connected to the sidewall of the tail metal skin. The leading edge skin is fixedly mounted within the space formed by the variable camber drive unit. The device is equipped with a leading edge plate, on which a first rotating shaft and a second rotating shaft arranged side by side are rotatably connected. A first gear and a second gear that mesh with each other are fixedly connected to the first and second rotating shafts, respectively. The top of the first and second gears are provided with wire grooves, and SMA metal wires are wound and anchored in the wire grooves. Rotating one of the first gears and the second gears can release the SMA metal wires and retract the other gears. A tail hook is fixedly provided at the tail end of the deformable cell, and the SMA metal wires extend along the inner wall of the sliding skin to the tail hook and are anchored thereon.

[0008] Furthermore, a drive motor is fixedly mounted on the leading edge plate. The output end of the drive motor is connected to the first rotating shaft and the second rotating shaft through a transmission assembly. The drive motor is used to output rotational power and cause one of the first rotating shaft and the second rotating shaft to rotate through the transmission assembly.

[0009] Furthermore, the transmission assembly includes a first bevel gear fixedly mounted on the output end of the drive mechanism, and a worm gear rotatably mounted on the leading edge plate. The worm gear is perpendicular to the output end of the drive mechanism. One end of the worm gear is fixedly connected to a second bevel gear that meshes with the first bevel gear. A worm wheel that meshes with the worm gear is fixedly mounted on one of the first rotating shaft and the second rotating shaft. The worm gear is rotatably disposed between the first rotating shaft and the second rotating shaft.

[0010] Furthermore, the sliding skin is composed of alternating overlapping hard sealing layers and soft sealing layers in a scale-like manner.

[0011] Furthermore, sealing layers for covering deformable cells are fixed on both sides of the sliding skin. The sealing layers are composed of alternating overlapping hard sealing layers and soft sealing layers in a scale-like manner.

[0012] Furthermore, two bearing support plates perpendicular to the front edge plate are fixedly provided on the front edge plate. The worm is rotatably connected to one of the two bearing support plates through a first bearing, and the worm is rotatably connected to the other of the two bearing support plates through a second bearing.

[0013] Furthermore, a third gear is fixedly installed on the first rotating shaft and arranged parallel to the first gear, and a fourth gear is fixedly installed on the second rotating shaft and arranged parallel to the second gear. The third gear and the fourth gear are meshed together. The bottom wall of the third gear and the bottom wall of the fourth gear are both provided with grooves. The turbine is arranged between the second gear and the fourth gear.

[0014] Furthermore, an SMA power supply box is fixedly installed on the front edge plate near the deformable cell, and a tail SMA power supply box is installed inside the tail hook. The SMA power supply box and the tail SMA power supply box are electrically connected to the SMA metal wire to jointly form an adjustable closed heating circuit.

[0015] Furthermore, the deformable cell is composed of multiple inner hexagonal nodes connected side by side with connecting ribs, and the area of ​​the inner circle composed of multiple inner hexagonal nodes decreases sequentially along the direction of the metal skin near the tail.

[0016] Furthermore, when the wing undergoes three-dimensional deformation, the control system sends different deflection commands to the drive motors at different positions along the span, so that the drive motors at different positions perform different number of rotations, thereby generating a deformation displacement difference between adjacent variable camber drive units, and smoothing the entire wing surface through the flexible skin.

[0017] The beneficial effects of this invention are as follows: 1. This invention possesses high surface smoothness and excellent torsional stiffness. The midsection of the mechanism adopts a chiral hexagonal cell skeleton with negative Poisson's ratio characteristics, which allows the wing to easily generate high compliant bending in the longitudinal direction while maintaining high torsional stiffness in the spanwise direction. Combined with the laminated sliding skin, the arc length difference is compensated by micro-sliding, eliminating the surface physical wrinkles and splicing gaps caused by continuous variable curvature, thereby significantly improving the lift-to-drag ratio of the wing in complex aerodynamic environments.

[0018] 2. This invention achieves both bending accuracy compensation and rapid response. It innovatively introduces SMA wire at the drive end to replace the ordinary traction cable. Utilizing the phase change contraction effect of SMA wire when heated, it actively offsets the unavoidable backlash between the micro bevel gear and worm gear pair during transmission, achieving high-precision compensation when the wing has a small curvature. Simultaneously, the transmission mechanism of the mechanical structure, combined with the heating and contraction characteristics of SMA, can greatly improve the deformation speed.

[0019] 3. This invention achieves high drive stability and self-locking function within a limited space. The mechanism uses miniature bevel gears to convert the spatial arrangement of core components, integrating a worm gear structure within the confined space of the wing's leading edge. Utilizing the inherent self-locking characteristics of the worm gear, the motor can be unloaded after the mechanism reaches a preset curvature, resisting the "rebound" caused by strong aerodynamic loads without consuming energy, greatly enhancing the reliability and energy efficiency of the mechanism in harsh flight missions.

[0020] 4. This invention significantly improves the anti-flutter capability of wings in complex aerodynamic environments. This mechanism deeply integrates a negative Poisson's ratio chiral skeleton with SMA wires to construct a rigid-flexible coupling system with active damping adjustment. Compared to the aeroelastic flutter easily generated by traditional rigid linkage mechanisms during high-speed flight, the chiral cell structure in this invention can effectively absorb high-frequency vibration energy through node rotation. Simultaneously, utilizing the internal friction characteristics of SMA wires at different phase transition stages, the system can adjust the dynamic stiffness of the mechanism in real time according to the flight load. This not only avoids structural fatigue damage caused by mechanical resonance but also significantly broadens the safe flight envelope of the aircraft, enabling it to maintain extremely high shape stability and flight quality even under turbulent or highly dynamic maneuvering conditions. Attached Figure Description

[0021] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration: Figure 1 This is a schematic diagram showing the arrangement of the transmission components of the present invention; Figure 2 This is a schematic diagram of the wing sidewall structure of the present invention; Figure 3 This is a schematic diagram of the connection between the sliding skin section and the tail metal skin of the present invention; Figure 4 This is a schematic diagram of the structure of the deformable cell body of the present invention; Figure 5 This is a schematic diagram of the spanwise structure of the wing of the present invention.

[0022] The following components are labeled in the attached diagram: leading edge plate 1, drive motor 2, nut 3, bolt 4, first bevel gear 5, second bevel gear 6, first bearing 7, bearing support plate 8, first gear 9, wire groove 10, second gear 11, worm 12, worm wheel 13, second bearing 14, SMA power supply box 15, third gear 16, fourth gear 17, first shaft 18, second shaft 19, third bearing 20, leading edge skin 21, pulley 22, SMA metal wire 23, tail hook 24, tail SMA power supply box 25, hard sealing layer 26, soft sealing layer 27, sliding skin 28, tail metal skin 29, deformable cell 30, flexible skin 31. Detailed Implementation

[0023] like Figures 1-5As shown, the present invention discloses a variable camber wing based on differential gear and SMA composite drive. From the perspective of overall spatial layout, the wing is mainly composed of three closely coupled parts: a rigid drive nacelle at the front end, a flexible variable camber zone in the middle section, and a passive deflection zone at the rear end. Inside the rigid drive nacelle at the front, the leading edge plate 1 serves as the basic load-bearing reference for the entire system. The drive motor 2 is securely suspended on it by bolts 4 and nuts 3. The output shaft of the drive motor 2 is fixedly connected to a first bevel gear 5, which meshes with a vertically arranged second bevel gear 6, thereby converting the vertically downward rotational power of the motor into horizontal rotational power. The second bevel gear 6 is fixedly sleeved on a horizontally arranged first rotating shaft 18 through a keyway. The two ends of the first rotating shaft 18 are tightly fitted and pass through a first bearing 7. The first bearing 7 is press-fitted into two parallel bearing support plates 8, and the root of the bearing support plate 8 is rigidly connected to the leading edge plate 1. This overall configuration, which arranges the power source laterally and completes a 90-degree spatial turn through a micro bevel gear set, greatly optimizes the volume utilization rate in the narrow enclosed space of the wing leading edge, allowing the high-torque motor to be perfectly housed inside the thin-walled wing. Meanwhile, the high-rigidity double-support point limiting structure constructed by the bearing support plate 8 and the first bearing 7 not only ensures the spatial stability of the transmission shaft system when subjected to extremely high starting torque and aerodynamic impact, but also completely avoids gear slippage failure that is prone to occur in the early stage of transmission.

[0024] A single-start worm gear 12 is fixedly installed between the first rotating shaft 18 and the second rotating shaft 19. A horizontally placed worm wheel 13 meshes perpendicularly with the worm gear 12. The center of the worm wheel 13 is fixedly connected to the vertically arranged second rotating shaft 19. In order to withstand the huge radial and axial combined loads generated during system operation, the two ends of the worm gear 12 are respectively embedded with a first bearing 7 and a second bearing 14. Through the positioning of these high-precision bearings, the meshing center distance of the worm wheel pair is ensured to remain constant. By introducing this pair of worm wheel transmission modules at the core hub of the transmission chain, this invention utilizes the physical absolute self-locking characteristic brought about by the small lead angle of the single-start worm gear. This allows the drive motor 2 to be completely de-energized and unloaded after the wing completes the target camber deformation in a complex high-speed airflow environment. Faced with huge aerodynamic restoring torque, the mechanism can firmly maintain the existing wing attitude by relying solely on the static friction self-locking of the worm wheel and worm gear. This not only significantly reduces the electrical energy consumption of unmanned aerial vehicles (UAVs) in maintaining control surface attitude during long-endurance missions, but also fundamentally eliminates the abnormal "bounce" phenomenon of wings caused by sudden changes in aerodynamic loads, greatly improving the absolute safety of flight control and the system's energy efficiency ratio.

[0025] Following the self-locking hub is a sophisticated four-gear differential traction system. On the vertical second shaft 19, a second gear 11 is coaxially fixed above the worm gear 13, and a fourth gear 17 is coaxially fixed below the worm gear 13. The second gear 11 and fourth gear 17 act as driving gears, rotating in the same direction and at the same speed as the worm gear 13. To achieve differential reverse output, driven gear sets are arranged in parallel mesh to the sides of the driving gears; specifically, the first gear 99 meshes with the second gear 11, and the third gear 16 meshes with the fourth gear 17. In this structure, the top or bottom surfaces of these four gears are integrally machined with cylindrical grooves 10 of strictly uniform depth for winding and accommodating the subsequent traction cable. This ingenious differential meshing layout ensures that when the main shaft drives the second gear 11 and fourth gear 17 to perform the "winding" action, the first gear 9 and third gear 16 are mechanically forced to rotate in the opposite direction to perform the "release" action. The beneficial effect of this design is that, through purely mechanical physical constraints, it ensures that the release length of the traction medium on the upper surface of the wing and the tightening length of the traction medium on the lower surface remain absolutely and precisely equal at any given moment. This characteristic allows the upper and lower surfaces and internal frame of the variable-camber wing to be subjected to completely symmetrical, counter-current traction, completely eliminating the stress accumulation and frame distortion phenomena caused by synchronization control errors in traditional multi-servo independent cable-operated systems. It also avoids unintended roll and pitch moment offsets caused by uneven force on the two wing surfaces, giving the aircraft a purer and more stable aerodynamic control response.

[0026] To further overcome the inherent precision bottleneck of pure mechanical transmission, this mechanism abandons the traditional steel wire rope and innovatively introduces SMA metal wire 23 into the differential pull-wire circuit. One end of the SMA metal wire 23 is wound and anchored inside the wire groove 10 of each gear, and after being led out, it is smoothly guided by the pulley 22 installed at the leading edge spacer, and then extends rearward along the upper and lower surfaces of the wing midsection, finally being firmly anchored in the tail hook 24 structure at the trailing edge. In order to accurately excite and control this flexible traction medium, an SMA power box 15 is arranged inside the leading section of the wing, and a tail SMA power box 25 is embedded in the tail hook 24. Together with the SMA metal wire 23, they form an adjustable closed heating circuit. The advantage of this composite drive compensation design is that although the preceding worm gear and differential gear set provide strong macroscopic driving force and reliable self-locking, machining tolerances and backlash during gear meshing are unavoidable. During high-speed flight, these minute air gaps are amplified by airflow, causing high-frequency flutter at the tail of the wing. This invention utilizes the PWM modulated current output from the SMA power supply box to induce a martensitic-to-austenitic phase transformation in the SMA wire 23 due to Joule heating, generating significant contractile internal stress. This powerful preload pulls the entire transmission chain in the reverse direction, forcing all gear teeth to mesh tightly against the working surface, thus achieving fine-tuning.

[0027] In the core load-bearing and external shaping area of ​​the wing midsection, the internal skeleton adopts a deformable cell 30 composed of multiple internal hexagonal nodes and connecting rib arrays. This chiral metamaterial skeleton with negative Poisson's ratio characteristics can provide huge compliant tensile and compressive strain in the chord direction, while maintaining extremely high torsional stiffness in the spanwise direction. More importantly, the external wing protection system consists of the leading edge skin 21 at the front, the tail metal skin 29 at the rear, and the sliding skin 28 covering the midsection. To solve the problems of skin wrinkling and aerodynamic load adaptability under continuous deformation, the sliding skin 28 in this embodiment innovatively adopts a composite sealing structure that combines rigidity and flexibility, which is composed of a hard sealing layer 26 and a soft sealing layer 27 that are alternately overlapped in a scale-like manner. Throughout the variable camber operation, the synergistic effect of this sealing design is exceptionally remarkable: when the wing undergoes significant bending, the rigid sealing layer 26, due to its extremely high out-of-plane stiffness, experiences almost no geometric deformation; the enormous change in the system's geometric arc length is entirely absorbed by the large-scale elastic stretching or compression of the soft sealing layer 27. This motion mode of "rigid units maintaining shape, soft units changing length" allows the soft sealing layer 27 to perfectly conform to the macroscopic deformation of the internal deformable cell 30, avoiding interlayer peeling and wrinkle interference during deformation as is common in traditional integral flexible skin 31, while also achieving continuous and seamless aerodynamic sealing, isolating the internal precision gear assembly from external dust and moisture. More importantly, the rigid sealing layer 26 with minimal deformation bears most of the high-speed aerodynamic normal pressure difference from the outside, fundamentally preventing the "bulging" or "collapse" phenomenon that is very easy to occur in the negative pressure area of ​​the flexible skin 31, ensuring that the wing can maintain a full and smooth laminar shape under any bending attitude, thereby reducing the parasitic drag of flight to the lowest level.

[0028] By integrating the aforementioned independent yet highly collaborative modules, the complete implementation and operation of this invention presents a highly coherent rigid-flexible coupling process. When the flight control system issues a command, the drive motor 2 starts, and after a 90-degree reversal of the bevel gear set, it drives the worm gear 12 and worm wheel 13 to rotate forcefully. The worm wheel 13 drives the coaxial differential gear set to rotate, and through a mechanically forced synchronous logic of contraction and release, it pulls the SMA metal wires 23 on the upper and lower surfaces. After a reversal of the pulley 22, it pulls the tail hook 24, forcing the chiral deformable cell 30 inside the middle section to undergo macroscopic compliant bending. Accompanying the deformation of the skeleton, the soft sealing layer 27 in the outer sliding skin 28 elastically expands and contracts, while the hard sealing layer 26 slides and maintains its shape, allowing the wing to smoothly achieve the target camber. Subsequently, the motor stops, and the worm gear structure instantly intervenes to achieve mechanical lock-up, resisting the huge external airflow rebound force. Finally, the SMA power supply boxes 15 at both ends and the SMA power supply box 25 at the tail supply precise current to the SMA metal wire 23, completing the final step of locking and high-frequency vibration reduction.

[0029] To achieve the aforementioned three-dimensional continuous deformation effect of the wing, in the actual assembly of the wing, multiple independent variable camber drive units are arranged side-by-side along the spanwise at a designed spacing, such as... Figure 5 As shown, the drive servo 2 and SMA power box 15 in each independent camber drive unit are connected to the aircraft's main control bus and receive independent addressing and differential control.

[0030] When the wing needs to perform three-dimensional deformation, the computer sends different deflection commands to the drive motors 2 at different positions along the span. For example, when implementing wing washout control, the drive motor 2 near the wing root needs to perform a larger number of forward rotations, thus creating a large curvature bend in the root profile; while towards the wingtip, the rotation speed of the servo motors in each unit decreases step by step. During this process, a deformation displacement difference inevitably occurs between adjacent drive units. The different units are connected by a flexible skin 31, thus making the entire wing surface smooth. At the same time, the internal deformable cells 30 rely on the compliant deflection of their nodal links in the spanwise direction to coordinate the internal stress, thereby physically realizing a smooth three-dimensional variable camber surface.

[0031] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A variable camber wing based on differential gear and SMA composite drive, characterized in that, The system includes multiple independently driven variable camber drive units arranged side-by-side along the wing span. Adjacent variable camber drive units are connected by a flexible skin. Each variable camber drive unit includes a skin protective shell, which comprises a leading edge skin, a sliding skin, and a tail metal skin that are fixedly connected in sequence. Both sides of the sliding skin are fixedly connected to deformable cells with negative Poisson bit properties. The tail end of the deformable cells is fixedly connected to the side wall of the tail metal skin. A leading edge plate is fixedly installed in the space formed by the leading edge skin. A first rotating shaft and a second rotating shaft arranged side-by-side are rotatably connected to the leading edge plate. A first gear and a second gear that mesh with each other are fixedly connected to the first and second rotating shafts, respectively. The top of the first and second gears are provided with grooves, and SMA metal wires are wound and anchored in the grooves. Rotating one of the first gears and the second gear can release the SMA metal wires and retract the other gears. A tail hook is fixedly provided at the tail end of the deformable cells, and the SMA metal wires extend along the inner wall of the sliding skin to the tail hook and are anchored thereon.

2. The variable camber wing based on differential gear and SMA composite drive according to claim 1, characterized in that: A drive motor is fixedly mounted on the leading edge plate. The output end of the drive motor is connected to the first rotating shaft and the second rotating shaft through a transmission assembly. The drive motor is used to output rotational power and cause one of the first rotating shaft and the second rotating shaft to rotate through the transmission assembly.

3. The variable camber wing based on differential gear and SMA composite drive according to claim 2, characterized in that: The transmission assembly includes a first bevel gear fixedly mounted on the output end of the drive mechanism and a worm gear rotatably mounted on the leading edge plate. The worm gear is perpendicular to the output end of the drive mechanism. A second bevel gear meshing with the first bevel gear is fixedly connected to one end of the worm gear. A worm wheel meshing with the worm gear is fixedly mounted on one of the first rotating shaft and the second rotating shaft. The worm gear is rotatably disposed between the first rotating shaft and the second rotating shaft.

4. The variable camber wing based on differential gear and SMA composite drive according to claim 1, characterized in that: The sliding skin is composed of alternating overlapping hard and soft sealing layers in a scale-like manner.

5. The variable camber wing based on differential gear and SMA composite drive according to claim 1, characterized in that: The sliding skin has sealing layers fixed on both sides to cover the deformable cells. The sealing layers are composed of hard sealing layers and soft sealing layers that are alternately overlapped in a scale-like manner.

6. The variable camber wing based on differential gear and SMA composite drive according to claim 3, characterized in that: Two bearing support plates perpendicular to the front edge plate are fixedly installed on the front edge plate. The worm is rotatably connected to one of the two bearing support plates through a first bearing, and the worm is rotatably connected to the other of the two bearing support plates through a second bearing.

7. The variable camber wing based on differential gear and SMA composite drive according to claim 6, characterized in that: A third gear is fixedly installed on the first rotating shaft and arranged in parallel with the first gear. A fourth gear is fixedly installed on the second rotating shaft and arranged in parallel with the second gear. The third gear and the fourth gear are meshed. The bottom wall of the third gear and the bottom wall of the fourth gear are both provided with grooves. The worm gear is arranged between the second gear and the fourth gear.

8. The variable camber wing based on differential gear and SMA composite drive according to claim 1, characterized in that: An SMA power supply box is fixedly installed on the front edge plate near the deformable cell body, and a tail SMA power supply box is installed inside the tail hook. The SMA power supply box and the tail SMA power supply box are electrically connected to the SMA metal wire to jointly form an adjustable closed heating circuit.

9. The variable camber wing based on differential gear and SMA composite drive according to claim 1, characterized in that: The deformable cell is composed of multiple inner hexagonal nodes and connecting ribs arranged side by side, and the area of ​​the inner circle composed of multiple inner hexagonal nodes decreases sequentially along the direction of the metal skin near the tail.

10. The variable camber wing based on differential gear and SMA composite drive according to any one of claims 1-9, characterized in that: When the wing undergoes three-dimensional deformation, the control system sends different deflection commands to the drive motors at different positions along the span, so that the drive motors at different positions perform different number of rotations, thereby generating a deformation displacement difference between adjacent variable camber drive units, and smoothing the entire wing surface through the flexible skin.

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