Winglet, fixed-wing aircraft and method for controlling airfoil profile of winglet

Abstract

The present invention relates to a winglet which is provided at a spanwise outer side of a wing of a fixed-wing aircraft and comprises: a support structure which supports the winglet; the skin is attached to the supporting structure and comprises an upper skin body arranged on the upper portion of the supporting structure and a lower skin body arranged on the lower portion of the supporting structure, and a leading edge skin body is formed at the position where the upper skin body and the lower skin body are connected; the piezoelectric device is attached to the inner surface of at least one of the upper skin, the lower skin and the leading edge skin, and the piezoelectric device can be driven to deform, so that the skin deforms along with deformation of the piezoelectric device. By means of the arrangement, the wing shape of the winglet can be changed according to expectation, and therefore the winglet with the high-low-speed aerodynamic performance is achieved in an active flow control mode. In addition, the invention also relates to a fixed-wing aircraft and a method for controlling an airfoil of a winglet.

Description

Technical Field

[0001] The present invention relates to a winglet and to a fixed-wing aircraft. In addition, the present invention also relates to a method for controlling the airfoil of the winglet. Background Art

[0002] Winglets are a signature technology of advanced civil aircraft. By blocking the turbulence formed at the wingtip by the pressure difference between the upper and lower surfaces of the wing, winglets can effectively weaken the strength of the wingtip vortex, increase the effective aspect ratio of the wing, reduce induced drag and increase lift, significantly improving the lift-to-drag ratio of advanced civil aircraft.

[0003] The design point of the winglet is generally selected as the cruising state of a fixed-wing aircraft (such as an airplane), hoping to achieve the best cruising lift-to-drag ratio. For supercritical wings, it is required to reasonably design the winglet airfoil to avoid strong shock waves on the surface, and airfoils with a small leading edge radius and relative thickness are often used. On the other hand, in the low-speed, high-lift state with the lift-enhancing device open, the angle of attack at which the winglet separates should be greater than the angle of attack at which the wing body separates, to prevent adverse situations such as violent rolling or loss of longitudinal stability. At this time, it is more advantageous to use an airfoil with a larger leading edge radius and relative thickness.

[0004] In view of the contradiction between the high-speed and low-speed aerodynamic design requirements of winglets, if winglets with variable airfoil capability are used, the low-speed aerodynamic characteristics of the winglets can be improved while maintaining the cruise lift-to-drag ratio, and the high-speed and low-speed performance of the winglets can be fully exploited, which can further enhance the competitiveness of advanced civil aircraft.

[0005] If traditional mechanical structures are used to drive the deformation of the wing, the deformed wing will bear a large weight cost, which may even exceed the aerodynamic benefits brought by the wing deformation. The new technologies currently being developed for winglets or other wing shape changes mainly include shape memory alloys to drive wing deformation.

[0006] For example, in the invention patent with publication number CN1 02951286A and titled "Variable Camber Fluid Dynamic Fuselage Using Optimized Intelligent Materials" filed by Boeing on August 16, 2012, a multi-segment memory alloy was proposed to realize the variable camber mechanism of the trailing edge of the wing. In the invention patent with publication number CA2782893A1 and titled "Variable Curved Surface Fluid-Dynamic Body Using Optimized Intelligent Materials" filed by Boeing on July 11, 2012, a design method for memory alloy materials suitable for variable camber mechanisms was proposed. The main difficulty of shape memory alloy technology is that shape memory alloys themselves are difficult to prepare, have high processing costs, and require additional heating and cooling equipment to achieve different shape switching.

[0007] Therefore, it is necessary to improve the driving method of the prior art so as to provide an improved winglet which can overcome one or more disadvantages of the prior art. Summary of the invention

[0008] The purpose of the present invention is to provide a wingtip winglet, which can change the airfoil characteristics, such as leading edge radius, thickness distribution, mid-arc curvature, etc. according to different configuration states and flight conditions, so as to achieve a wingtip winglet that takes into account both high-speed and low-speed aerodynamic performance in an active flow control manner.

[0009] According to one aspect of the present invention, a wingtip winglet is proposed, which can be arranged at the span-wise outer side of the wing of a fixed-wing aircraft and can include: a supporting structure, which supports the wingtip winglet; a skin, which is attached to the supporting structure and includes an upper skin arranged at the upper part of the supporting structure and a lower skin arranged at the lower part of the supporting structure, wherein a leading edge skin is formed at the position where the upper skin is connected to the lower skin; and a piezoelectric device, which is attached to the inner surface of at least one of the upper skin, the lower skin and the leading edge skin, and the piezoelectric device can be driven to deform so that the skin deforms following the deformation of the piezoelectric device.

[0010] By attaching the piezoelectric device to the inner surface of the skin and making the skin deform following the deformation of the piezoelectric device, the wing shape of the winglet can be changed as desired, thereby realizing a winglet that takes into account both high and low speed aerodynamic performance in an active flow control manner. This structure is relatively simple to manufacture, has low processing and installation costs, and does not require the arrangement of additional heating or cooling equipment, which reduces the complexity of the winglet and improves reliability.

[0011] According to the above aspects of the present invention, preferably, the piezoelectric device may include an upper piezoelectric sheet attached to the inner surface of the upper skin, a lower piezoelectric sheet attached to the inner surface of the lower skin, and a leading edge piezoelectric sheet attached to the inner surface of the leading edge skin.

[0012] This arrangement allows the piezoelectric sheets to act directly on the skin, and through the cooperation of piezoelectric sheets arranged at different skin positions, a variety of control strategies can be implemented, thereby improving the sensitivity and flexibility of wing shape control.

[0013] According to the above aspects of the present invention, preferably, the upper piezoelectric sheet and the lower piezoelectric sheet can realize synchronous movement or differential movement under the action of electrical signals to change the airfoil thickness or the front section curvature of the winglet, and the leading edge piezoelectric sheet can be extended or shortened under the action of electrical signals to change the leading edge radius of the leading edge skin.

[0014] This setting can adapt to high-speed cruise flight and low-speed, high-power-angle flight conditions, thereby improving the low-speed aerodynamic characteristics of the winglet while maintaining the cruise lift-to-drag ratio.

[0015] According to the above aspects of the present invention, preferably, in the synchronous movement of the upper piezoelectric sheet and the lower piezoelectric sheet, the upper piezoelectric sheet and the lower piezoelectric sheet are simultaneously extended or shortened to change the airfoil thickness of the winglet, and in the differential movement of the upper piezoelectric sheet and the lower piezoelectric sheet, one of the upper piezoelectric sheet and the lower piezoelectric sheet is extended or shortened, while one of the upper piezoelectric sheet and the lower piezoelectric sheet is shortened or extended in the opposite direction, or remains unchanged, to change the curvature of the front section of the airfoil of the winglet.

[0016] This arrangement can selectively change the thickness of the winglet airfoil or the camber of the front section of the winglet airfoil, thus changing the camber of the front section of the airfoil. In this way, according to the aircraft configuration and flight conditions, when in high-speed cruising state, the piezoelectric sheet does not work and the winglet maintains the initial airfoil; when in a high angle of attack state, the optimal leading edge radius, airfoil thickness and front section camber combination are selected, and electrical signals are output to each group of piezoelectric sheets to accurately control the change of the winglet airfoil.

[0017] According to the above aspects of the present invention, preferably, the upper piezoelectric sheet can be bonded to the inner surface of the upper skin, the lower piezoelectric sheet can be bonded to the inner surface of the lower skin, and the leading edge piezoelectric sheet can be bonded to the inner surface of the leading edge skin.

[0018] In this way, it is possible to ensure the connection strength between the piezoelectric sheet and the inner surface of the skin while avoiding damaging the aerodynamic shape of the winglet.

[0019] According to the above aspects of the present invention, preferably, the piezoelectric device may include a plurality of piezoelectric sheets arranged at intervals along the span direction of the winglet.

[0020] This arrangement can prevent the piezoelectric strip from deforming in the chord direction due to the Poisson effect, which may affect the aerodynamic shape.

[0021] According to the above aspects of the present invention, preferably, the deformation of the piezoelectric device can occur in the chord direction. In this way, when the piezoelectric sheet is stretched, the side of the skin bonded to the piezoelectric sheet is stretched by the piezoelectric sheet, and according to the plane section hypothesis of elastic mechanics, the normal direction of the skin section will rotate, so that the skin bends away from the piezoelectric sheet, and when the piezoelectric sheet contracts, the skin will bend in the opposite direction, thereby changing the airfoil thickness and the curvature of the front section.

[0022] According to the above aspects of the present invention, preferably, the piezoelectric device can be made of MFC piezoelectric fiber composite material. The flexible polymer in MFC can protect the ceramic from being damaged under high load, so that the piezoelectric device can withstand large loads and high strains.

[0023] According to the above aspects of the present invention, in order to achieve desired aerodynamic performance, preferably, the amount of local deformation of the skin caused by the piezoelectric device during deformation may be no less than 5 mm.

[0024] According to another aspect of the present invention, a fixed-wing aircraft is provided. The wings of the fixed-wing aircraft may be provided with the winglets according to the above aspects.

[0025] According to another aspect of the present invention, a method for controlling the airfoil of a winglet is proposed, comprising: providing the winglet according to the above aspects; in a high-speed cruising state of the fixed-wing aircraft, the piezoelectric device does not work and the winglet maintains the initial airfoil; in a low-speed and high-lift state of the fixed-wing aircraft, the piezoelectric device works, and the radius of the leading edge skin is increased, and the relative thickness between the upper skin and the lower skin is increased, and the curvature of the front section of the airfoil is increased.

[0026] Therefore, the winglet of the present invention can meet the use requirements, overcome the shortcomings of the prior art and achieve the predetermined purpose. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to further clearly describe the winglet according to the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. In the accompanying drawings:

[0028] Figure 1 is a schematic diagram of a fixed-wing aircraft with winglets; and

[0029] Figure 2 is a schematic diagram of a winglet according to a non-limiting embodiment of the present invention, showing the chord-wise arrangement of the piezoelectric patch;

[0030] Figure 3 is a schematic diagram of a piezoelectric device according to the present invention on a winglet, showing the spanwise arrangement of the piezoelectric sheets;

[0031] Figure 4 Taking a flat skin as an example, a schematic diagram showing how a piezoelectric sheet drives the skin to deform is shown; and

[0032] Figure 5 Schematic detection positions of wing shape changes of a winglet according to a non-limiting embodiment of the present invention are shown.

[0033] The above drawings are merely schematic and are not drawn strictly to scale. List of reference numerals in the drawings and embodiments: 1000 - A fixed-wing aircraft, comprising:

[0034] 100 - Winglets, including:

[0035] 10- Support structure, including:

[0036] 11- front beam;

[0037] 12- rear beam;

[0038] 13-box segment rib;

[0039] 14-front edge cabin rib;

[0040] 15-leading edge compartment;

[0041] 16-winglet box segment;

[0042] 17- trailing edge compartment;

[0043] 20-Skins, including:

[0044] 21- upper skin;

[0045] 22-lower skin;

[0046] 23-leading edge skin;

[0047] 24-First detection point;

[0048] 25- Second detection point;

[0049] 26-the third detection point;

[0050] 30- A piezoelectric device, comprising:

[0051] 31-upper piezoelectric sheet;

[0052] 32-lower piezoelectric sheet;

[0053] 33-front edge piezoelectric patch;

[0054] 40- piezoelectric power supply;

[0055] 50-control device;

[0056] S1-first gap;

[0057] S2-second gap;

[0058] C-chord direction;

[0059] S - span direction. DETAILED DESCRIPTION

[0060] It should be understood that, unless expressly stated otherwise, the present invention may adopt various alternative orientations and step sequences. It should also be understood that the specific devices shown in the drawings and described in the specification are merely exemplary embodiments of the inventive concepts disclosed and defined herein. Therefore, unless otherwise expressly stated, the specific orientations, directions or other physical characteristics of the various embodiments disclosed should not be considered as limiting.

[0061] Figure 1 is a schematic diagram of a fixed-wing aircraft 1000 with winglets.

[0062] As shown and as a non-limiting example, the fixed-wing aircraft 1000 may be a fixed-wing aircraft such as a commercial passenger aircraft, and has a wing 200. A winglet 100 may be provided at the spanwise outer side of the fixed-wing aircraft 1000, whereby the winglet 100 may be the outermost portion of the wing 200.

[0063] The winglet 100 may have an airfoil that is vertical or oblique relative to the airfoil of the wing 200. By blocking the turbulence formed at the wing tip by the pressure difference between the upper and lower surfaces of the wing 200, the winglet 100 can effectively weaken the strength of the wing tip vortex, increase the effective aspect ratio of the wing 200, reduce the induced drag and increase the lift, and significantly improve the lift-to-drag ratio of the fixed-wing aircraft 1000. In some designs, the winglet 100 can also provide additional stability, especially in crosswind or turbulent conditions.

[0064] Figure 2 is a schematic diagram of a winglet 100 according to a non-limiting embodiment of the present invention, showing the chord-wise arrangement of the piezoelectric patch, and Figure 3 FIG. 1 is a schematic diagram of a piezoelectric device according to the present invention on a winglet 100 , showing the spanwise arrangement of the piezoelectric sheets.

[0065] As shown in the figures, the winglet 100 may mainly include a support structure 10 , a skin 20 and a piezoelectric device 30 .

[0066] The support structure 10 may be used to support a winglet 100. Figure 3 As schematically shown in FIG. 1 , the support structure 10 may include spars arranged generally in a spanwise direction and ribs arranged generally in a chordwise direction.

[0067] As an example, the wing spar may include a front spar 11 and a rear spar 12, and the wing rib may include a box rib 13 and a leading edge cabin rib 14. The box rib 13 may be connected between the front spar 11 and the rear spar 12, and the leading edge cabin rib 14 may be connected to the front spar 11. In addition, on the spanwise inner side of the winglet 100 (i.e., the side of the wing 200 close to the fuselage), the support structure 10 may further include: a leading edge cabin 15, a winglet box section 16, and a trailing edge cabin 17.

[0068] The skin 20 may be attached to the support structure 10 , such as riveted to corresponding spars or ribs, to form a desired aerodynamic shape and to bear and transfer aerodynamic loads.

[0069] like Figure 2 As schematically shown in FIG. 1 , the skin 20 may include an upper skin 21 disposed on the upper portion of the support structure 10 and a lower skin 22 disposed on the lower portion of the support structure 10 , wherein a leading edge skin 23 is formed at a position where the upper skin 21 and the lower skin 22 are connected.

[0070] The skin 20 may be made of various metal or non-metal materials, for example, metal materials such as aluminum, titanium and alloys thereof, composite materials such as carbon fiber, and the like.

[0071] like Figure 2 and 3 As schematically shown in the figure, the piezoelectric device 30 can be attached to the inner surface of at least one of the upper skin 21, the lower skin 22 and the leading edge skin 23, and can be driven to deform, for example, to deform under the drive of a piezoelectric drive device such as a piezoelectric power supply 40, so that the skin 20 deforms following the deformation of the piezoelectric device 30.

[0072] As an example, the piezoelectric device 30 may include an upper piezoelectric sheet 31 attached to the inner surface of the upper skin 21 , a lower piezoelectric sheet 32 ​​attached to the inner surface of the lower skin 22 , and a leading edge piezoelectric sheet 33 attached to the inner surface of the leading edge skin 23 .

[0073] For example, the piezoelectric sheets can be bonded or welded to the inner surface of the skin 20. In particular, each piezoelectric sheet can be connected to the inner surface of the skin 20 in a face-to-face bonding manner. As an example, the entire surface of each piezoelectric sheet is completely bonded to the inner surface of the skin 20, and the shape change of the piezoelectric sheet drives the shape change of the corresponding part of the skin 20 to which it is bonded.

[0074] An example of a bonding process of the piezoelectric sheet and the winglet 100 is as follows: the piezoelectric sheet and the skin 20 of the winglet 100 are bonded by using a room temperature curing epoxy resin adhesive. The thickness of the adhesive layer formed by the adhesive can be about 0.1 to 0.2 mm, and a vacuum bag can be used to compact the piezoelectric sheet, the adhesive and the skin 20, and the room temperature (25° C.) curing time is not less than 24 hours.

[0075] In this way, the upper piezoelectric sheet 31 can be bonded to the inner surface of the upper skin 21 via an adhesive, the lower piezoelectric sheet 32 ​​is bonded to the inner surface of the lower skin 22 , and the leading edge piezoelectric sheet 33 is bonded to the inner surface of the leading edge skin 23 .

[0076] As a non-limiting example, the piezoelectric sheet of the piezoelectric device 30 can be made of MFC (Macro Fiber Composite) piezoelectric fiber composite material. MFC piezoelectric fiber can be composited by ceramic fiber and polymer, and has the flexibility of polymer and the piezoelectric effect of piezoelectric ceramic. MFC utilizes the piezoelectric effect to convert mechanical energy into electrical energy, or vice versa, convert electrical energy into mechanical energy. When the MFC piezoelectric ceramic fiber sheet works as an actuator, the displacement can reach hundreds of microns or several hundred microns, and the output force can reach more than 693N.

[0077] like Figure 3As schematically shown in FIG. 1 , the piezoelectric device 30 may include a plurality of piezoelectric sheets spaced apart from each other along the span direction S of the winglet 100 .

[0078] Gaps can be set between each group of piezoelectric sheets in the span direction (such as the lower piezoelectric sheet 32 ​​and the leading edge piezoelectric sheet 33 shown in the figure). For example, there is a first gap S1 between adjacent lower piezoelectric sheets 32 in the span direction S, and there is a second gap S2 between adjacent leading edge piezoelectric sheets 33 in the span direction S. The size of the gap depends on the elongation performance and Poisson's ratio of the piezoelectric sheet. The main purpose of these gaps is to prevent the deformation of the skin span direction due to the Poisson effect that affects the aerodynamic shape when the piezoelectric sheet is elongated and deformed along the chord direction.

[0079] The deformation of the piezoelectric device 30 may mainly occur in the chord direction C. Thus, the three-dimensional movement of the piezoelectric sheet can be summarized as: elongation along the fiber direction (i.e., in the chord direction C), and contraction perpendicular to the fiber direction (i.e., in the span direction S) due to the Poisson effect. Preferably, this contraction deformation is limited to the range of a single piezoelectric sheet, and the thickness change of the piezoelectric sheet can be ignored.

[0080] Figure 4 Taking a plane skin as an example, a schematic diagram showing how the piezoelectric sheet drives the skin 20 to deform is shown. Figure 4 Take the upper piezoelectric sheet 31 adhered to the inner surface of the upper skin 21 as an example. Figure 4 The upper part in FIG. 1 is a view before the upper piezoelectric sheet 31 is extended. At this time, in order to more clearly illustrate the principle of the present invention, the upper skin 21 and the upper piezoelectric sheet 31 are shown in a flat state.

[0081] As an example, the piezoelectric sheet can be an elongated piezoelectric sheet. The effect of this type of piezoelectric sheet is that under a given voltage excitation, the length of the piezoelectric sheet along the fiber direction will increase, the length perpendicular to the fiber direction will decrease according to the Poisson's ratio, and the change in the thickness direction can be ignored. When the piezoelectric sheet is elongated, the side of the skin 20 bonded to the piezoelectric sheet is elongated by the piezoelectric sheet. According to the plane section assumption of elastic mechanics, the normal direction of the skin section will rotate, causing the skin to bend away from the piezoelectric sheet. Therefore, if Figure 4 As shown in the lower view, when the upper piezoelectric sheet 31 stretches, the upper skin 21 to which the upper piezoelectric sheet 31 is bonded will also stretch.

[0082] According to the above effects, four basic control modes (i.e., four basic skin deformation modes) and linear superposition based on the basic control modes can be constructed:

[0083] The first mode: when the upper piezoelectric sheet 31 and the lower piezoelectric sheet 32 ​​attached to the upper skin 21 and the lower skin 22 are both stretched, the upper skin 21 and the lower skin 22 are both bent in the direction away from the inner surface, that is, the upper skin 21 is deformed upward and the lower skin 22 is deformed downward, which has the effect of increasing the thickness of the local airfoil of the leading edge compartment 15 of the wingtip winglet 100.

[0084] Second mode: when only the upper piezoelectric sheet 31 of the upper skin 21 is extended, the upper skin 21 deforms upward and drives the lower skin 22 to move upward, which results in a reduction in the curvature of the local airfoil of the leading edge compartment 15 of the winglet 100. At this time, the lower piezoelectric sheet 32 ​​of the lower skin 22 can remain unchanged or shorten.

[0085] The third mode: when only the lower piezoelectric sheet 32 ​​of the lower skin 22 is extended, the lower skin 22 is deformed downward and drives the upper skin 21 to move downward, which has the effect of increasing the curvature of the local airfoil of the leading edge compartment 15 of the winglet 100. At this time, the upper piezoelectric sheet 31 of the upper skin 21 can remain unchanged or shorten.

[0086] Fourth mode: When the leading edge piezoelectric sheet 33 is stretched, the leading edge skin 23 moves away from the inner profile (for example, moves forward in the chordwise direction C, i.e. moves against the direction C), which has the effect of increasing the leading edge radius of the local airfoil of the leading edge compartment 15 of the winglet 100.

[0087] The piezoelectric sheet (e.g., the upper piezoelectric sheet 31, the lower piezoelectric sheet 32, or the leading edge piezoelectric sheet 33) can be connected to a piezoelectric power source 40 or a piezoelectric driving power source so that the piezoelectric sheet can produce a shape change, such as a micro-nano displacement change. In addition, the piezoelectric power source 40 can control the voltage and duration of the piezoelectric power source 40 via a control device 50. The control device 50 can be connected to an onboard computer so as to control the deformation of the piezoelectric sheet according to the flight state of the fixed-wing aircraft 1000. As a preferred embodiment, a sensor, such as a displacement sensor, etc., can also be provided on the skin 20 of the winglet 100 to sense the deformation of the skin 20, thereby realizing closed-loop control.

[0088] As an example, the upper piezoelectric sheet 31 and the lower piezoelectric sheet 32 ​​can realize synchronous movement or differential movement under the action of the electrical signal from the piezoelectric power supply 40 to change the airfoil thickness or the front section curvature of the wingtip 100, and the leading edge piezoelectric sheet 33 can be extended or shortened under the action of the electrical signal from the piezoelectric power supply 40 to change the leading edge radius of the leading edge skin 23.

[0089] In the synchronous movement of the upper piezoelectric sheet 31 and the lower piezoelectric sheet 32, the upper piezoelectric sheet 31 and the lower piezoelectric sheet 32 ​​can be extended or shortened at the same time to change the airfoil thickness of the winglet 100.

[0090] In the differential movement of the upper piezoelectric sheet 31 and the lower piezoelectric sheet 32, one of the upper piezoelectric sheet 31 and the lower piezoelectric sheet 32 ​​is extended or shortened, while one of the upper piezoelectric sheet 31 and the lower piezoelectric sheet 32 ​​is shortened or extended in the opposite direction, or remains unchanged, so as to change the curvature of the front section of the airfoil of the wingtip winglet 100.

[0091] For example, at this time, the upper piezoelectric sheet 31 may be extended, while the lower piezoelectric sheet 32 ​​may remain unchanged or shortened, so as to reduce the camber of the local airfoil of the leading edge compartment 15 of the winglet 100 .

[0092] As a preferred embodiment, the local deformation of the skin 20 caused by the piezoelectric device 30 during deformation is not less than 5 mm.

[0093] Figure 5 Schematic detection positions of the wing shape change of the winglet 100 according to a non-limiting embodiment of the present invention are shown.

[0094] As shown in the figure, when the airfoil camber changes mainly, that is, when the second mode or the third mode mentioned above is dominant, the detection position where the airfoil deformation reaches 5 mm is the first detection point 24, that is, the leading edge point of the winglet.

[0095] When the airfoil leading edge radius changes mainly, that is, when the fourth mode described above is dominant, the detection position where the airfoil deformation reaches 5 mm is the second detection point 25. The second detection point 25 is the position where the winglet has a 1% local chord length.

[0096] When the airfoil thickness changes mainly, that is, the first mode is dominant, the detection position where the airfoil deformation reaches 5 mm is the third detection point 26. The third detection point 26 is the middle section of the winglet leading edge compartment, that is, near the midpoint of the winglet leading edge and the winglet front beam.

[0097] As a non-limiting embodiment, a method for controlling the airfoil of a wingtip 100 may include: providing a wingtip 100 according to the present invention; in a high-speed cruising state of the fixed-wing aircraft, the piezoelectric device 30 does not work and the wingtip 100 maintains the initial airfoil; in a low-speed and high-lift state of the fixed-wing aircraft, the piezoelectric device 30 works, and the radius of the leading edge skin 23 is increased, and the relative thickness between the upper skin 21 and the lower skin 22 is increased.

[0098] It should be understood that the method steps described above are exemplary, and those skilled in the art may adjust the order of the method steps, add corresponding steps or delete relevant steps without departing from the scope of the present invention.

[0099] As used herein, the terms "inner surface" and "outer surface" indicating position or orientation, and the terms "first" and "second" used to indicate order are only intended to enable those of ordinary skill in the art to better understand the concept of the present invention shown in the form of a preferred embodiment, and are not intended to limit the present invention. Unless otherwise specified, all orders, positions or orientations are only used for the purpose of distinguishing one element / component / structure from another element / component / structure, and unless otherwise specified, do not represent any particular order, order of operation, direction or orientation. For example, in an alternative embodiment, the "first gap" may be the "second gap".

[0100] As used herein, unless otherwise indicated, the terms "substantially" and "approximately" are interpreted to mean plus or minus five percent of the value or range of values, or to mean a deviation of plus or minus five percent of the shape and / or position.

[0101] In summary, the winglet 100 according to the embodiment of the present invention overcomes the shortcomings of the prior art and achieves the intended purpose of the invention.

[0102] Although the winglet of the present invention is described above in conjunction with the preferred embodiments, those skilled in the art should recognize that the above examples are only for illustration and cannot be used as limitations of the present invention. Therefore, various modifications and variations can be made to the present invention within the spirit of the claims, and these modifications and variations will fall within the scope required by the claims of the present invention.

Claims

1. A winglet (100), the winglet being arranged at the spanwise outer side of a wing (200) and comprising: a supporting structure (10), the supporting structure supporting the winglet (100); a skin (20) attached to the support structure (10) and comprising an upper skin (21) arranged on the upper part of the support structure (10) and a lower skin (22) arranged on the lower part of the support structure (10), wherein a leading edge skin (23) is formed at a position where the upper skin (21) is connected to the lower skin (22); as well as A piezoelectric device (30) is attached to the inner surface of at least one of the upper skin (21), the lower skin (22) and the leading edge skin (23), and the piezoelectric device (30) can be driven to deform so that the skin (20) deforms following the deformation of the piezoelectric device (30).

2. The winglet (100) according to claim 1, characterized in that: The piezoelectric device (30) includes an upper piezoelectric sheet (31) attached to the inner surface of the upper skin (21), a lower piezoelectric sheet (32) attached to the inner surface of the lower skin (22), and a leading edge piezoelectric sheet (33) attached to the inner surface of the leading edge skin (23).

3. The winglet (100) according to claim 2, characterized in that: The upper piezoelectric sheet (31) and the lower piezoelectric sheet (32) can realize synchronous movement or differential movement under the action of an electrical signal to change the airfoil thickness or front section curvature of the winglet (100), and the leading edge piezoelectric sheet (33) can be extended or shortened under the action of an electrical signal to change the leading edge radius of the leading edge skin (23).

4. The winglet (100) according to claim 3, characterized in that: During the synchronous movement of the upper piezoelectric sheet (31) and the lower piezoelectric sheet (32), the upper piezoelectric sheet (31) and the lower piezoelectric sheet (32) are simultaneously extended or shortened to change the airfoil thickness of the winglet (100). During the differential motion of the upper piezoelectric sheet (31) and the lower piezoelectric sheet (32), one of the upper piezoelectric sheet (31) and the lower piezoelectric sheet (32) is extended or shortened, while one of the upper piezoelectric sheet (31) and the lower piezoelectric sheet (32) is shortened or extended in the opposite direction or remains unchanged, so as to change the curvature of the front section of the airfoil of the winglet (100).

5. The winglet (100) according to claim 2, characterized in that: The upper piezoelectric sheet (31) is bonded to the inner surface of the upper skin (21), the lower piezoelectric sheet (32) is bonded to the inner surface of the lower skin (22), and the leading edge piezoelectric sheet (33) is bonded to the inner surface of the leading edge skin (23).

6. The winglet (100) according to any one of claims 1 to 5, characterized in that: The piezoelectric device (30) comprises a plurality of piezoelectric sheets arranged at intervals along the span direction (S) of the winglet (100).

7. The winglet (100) according to any one of claims 1 to 5, characterized in that: The deformation of the piezoelectric device (30) occurs in a chordwise direction (C).

8. The winglet (100) according to any one of claims 1 to 5, characterized in that: The piezoelectric device (30) is made of MFC piezoelectric fiber composite material.

9. A fixed-wing aircraft (1000), wherein a wing (200) of the fixed-wing aircraft is provided with a winglet (100) according to any one of claims 1-8.

10. A method for controlling the airfoil of a winglet (100), comprising: Providing a winglet (100) according to any one of claims 1 to 8; When the fixed-wing aircraft is in a high-speed cruising state, the piezoelectric device (30) does not work, and the winglet (100) maintains an initial airfoil; In a low-speed, high-lift state of a fixed-wing aircraft, the piezoelectric device (30) operates, causing the radius of the leading edge skin (23) to increase, and the relative thickness between the upper skin (21) and the lower skin (22) to increase, thereby increasing the curvature of the front section of the airfoil.

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