CN112550664B - A variable-camber wing structure driven by shape memory alloys - Google Patents

Abstract

The invention discloses a variable camber wing structure driven by a shape memory alloy, which belongs to the technical field of aviation equipment. The wing structure mainly includes a flexible trailing edge structure 1 and a leading edge rigid segment 2 covered by a flexible skin; the flexible trailing edge structure 1 is formed by a plurality of rigid segments 4 hinged in sequence, which is integral with the leading edge rigid segment 2 A similar dinosaur tailbone structure is formed; the upper and lower airfoils of the flexible trailing edge structure have alloy wires along the chordwise direction of the airfoil. When the shape memory alloy wire group on the upper airfoil of the flexible trailing edge structure 1 is heated, its length becomes shorter, and the entire flexible trailing edge structure 1 deforms upward; otherwise, it deforms downward. The design of the wing is simple in structure and has the characteristics of large power-to-weight ratio, which can actively change the airfoil to obtain the best aerodynamic characteristics; the wing can obtain different aerodynamic characteristics; the modular assembly design is adopted, which greatly saves the interior space of the wing .

Description

A variable-camber wing structure driven by shape memory alloys

technical field

The invention belongs to the technical field of aviation equipment, and relates to a deformable flexible wing structure driven by a two-way shape memory alloy (SMA).

Background technique

At present, the deformable wing has become an important feature and development direction of future advanced aviation vehicles. Unlike fixed wings, deformable wings can change the shape of the wing according to different flight tasks and flight environmental conditions to obtain optimal flight performance. A herringbone flexible trailing edge has been proposed in the literature, which is characterized by using flexible materials as the trailing edge design of the main load-bearing structure. The main part of the airfoil has the characteristics of simple structure and easy processing. The length transition to fit the aerodynamic shape of the overall wing. However, due to the cooperative relationship between the trailing edge structure and the actuator, the overall support structure of the airfoil is often difficult to design, so it is difficult to integrate the flexible skin under the premise of maintaining a certain supporting capacity, and the leading edge structure is difficult to design. Unable to resist the resistance caused by the integral beam of the trailing edge, the actuator on the other side and the deformation of the skin, the deflection effect is not good.

Therefore, this design intends to use a multi-joint articulated multi-joint wing trailing edge structure to meet the requirements of maintaining good flight performance in changing flight environments.

SUMMARY OF THE INVENTION

The flight environment of the aircraft is continuously changing, and the aerodynamic parameters are also continuously changing, while the traditional fixed-wing aircraft can only achieve the best flight efficiency in a specific environment, and cannot adapt to the changeable environmental changes.

Transforming wing aircraft can use intelligent materials or other drivers to change the shape of the wing accordingly according to the changes in the flight environment and flight tasks, improve the aerodynamic characteristics and handling performance of the aircraft, increase lift and reduce drag, increase flight time and range, reduce Or eliminate the effects of buffeting, flutter and eddy current interference, so that the aircraft can complete a variety of flight tasks more efficiently.

In order to ensure that the aircraft can still have the best aerodynamic performance under different flight environments and flight mission conditions, this design is improved by using a new smart material shape memory alloy (SMA) to drive the wing to make the airfoil flexible, smooth and autonomously change. Its aerodynamic characteristics are seamless, small in size, light in weight, and fast in response. It can adapt to different flight conditions and complete various flight tasks more efficiently.

In order to solve the various defects of the traditional airfoil structure, the main purpose of the present invention is to design a variable wing structure by using two-way shape memory alloy, aiming to solve the problem that the aircraft cannot maintain the best aerodynamic performance under different flight conditions.

In order to achieve the above purpose, the double-pass shape memory alloy-driven deformed wing structure designed by the present invention mainly includes a flexible trailing edge structure 1 and a leading edge rigid section 2 covered by a flexible skin;

The flexible trailing edge structure 1 is constituted by a plurality of rigid segments 4 that are hinged in sequence, which together with the leading edge rigid segment 2 form an approximate dinosaur-like coccyx structure; the rigid segments 4 from the leading edge rigid segment 2 to the flexible trailing edge structure 1 , following the method of decreasing size in turn, so that the entire wing forms a smooth airfoil surface;

The structural features of each rigid segment 4 of the flexible trailing edge structure 1 are: its main body is a rectangular shell, and a front end bump 10 protrudes outward from the surface of each rigid segment adjacent to the previous adjacent rigid segment. The side with the next adjacent rigid segment is missing, so that the inner cavity of the rectangular housing of the rigid segment just accommodates the front end bump 10 of the next adjacent rigid segment; each rigid segment is connected to the front end convex of the next adjacent rigid segment. The blocks 10 are connected by a through cylindrical pin 12 to form a manner in which a plurality of rigid segments are hinged in sequence; on the upper and lower inner walls of the rigid segment housing, there are a plurality of parallel thin grooves 9 along the spanwise direction. , the size and position of the thin grooves 9 of each rigid segment 4 are corresponding, so that after all the rigid segments 4 are hinged in sequence, the thin grooves 9 are sequentially connected to a plurality of through grooves running through the entire flexible trailing edge structure. The memory alloy wire is placed in the plurality of through grooves, and the alloy wire is fixed to the alloy wire fixing end 5 of the flexible trailing edge structure along the chordwise direction of the airfoil.

During operation, when the shape memory alloy wire group on the upper airfoil of the flexible trailing edge structure 1 is heated, its length becomes shorter due to the temperature effect. Due to the existence of the shape memory alloy wire group on the lower airfoil, the entire flexible trailing edge structure 1 On the contrary, when the shape memory alloy wire group of the lower airfoil of the flexible trailing edge structure 1 is heated, the alloy wire of the lower airfoil shrinks due to the heat. Due to the existence of the shape memory alloy wire group of the lower airfoil, the entire flexible trailing edge Structure 1 will deform downwards.

In order to better assemble the deformed wing structure in a modular manner, a plurality of groups or more of the deformed wing structure may be arranged in the spanwise direction of the airfoil to form a modular assembly structure ( FIG. 5 ).

In order to make the deformed wing structure produce less resistance during deformation, a reversing structure can be added between the flexible trailing edge structure 1 and the leading edge rigid section 2 (Fig. 6), so that when the wing deforms upward or downward, Increase the underside or overside chord length.

The advantages of the present invention are:

1. The structure of the variable camber wing of this design is simpler than that of the traditional wing. At the same time, as the driver, the shape memory alloy has the characteristics of large power-to-weight ratio, which can actively change the airfoil and obtain the best aerodynamic characteristics.

2. The variable camber wing driven by the alloy wire realizes the quantitative change of the wing shape through the feedback control system of the shape memory alloy wire, so that the wing can obtain different aerodynamic characteristics.

3. The modular assembly design is adopted, which greatly saves the interior space of the wing.

Effects of the present invention: The airfoil of this design can achieve a deflection of more than 15 degrees with reference to the centerline of the wingtip under the condition of no wind load, and with the fixed point of the axis of the first section as the deflection reference point, the limit angle can be deflected about 10 degrees. The ultimate deflection time is about 4 seconds, and the recovery time is about 7 seconds.

Description of drawings

1 is a schematic structural diagram of an active section of a variable-camber wing structure in an embodiment;

FIG. 2 is a schematic diagram of a flexible trailing edge structure in an embodiment;

3 is a schematic diagram of a single joint structure of the rear edge in the embodiment;

4 is a schematic diagram of a flexible skin in an embodiment;

5 is a schematic diagram of the spanwise main-by-main structure of the wing structure in the embodiment;

FIG. 6 is a schematic structural diagram of a reversing mechanism for a bidirectional variable trailing edge wing provided in an embodiment.

In the figure, 1-flexible trailing edge structure, 2-leading edge rigid segment, 11-flexible skin.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific implementation methods.

The two-way shape memory alloy-driven deformed wing structure in this embodiment mainly includes a flexible trailing edge structure 1 and a leading edge rigid segment 2 covered by a flexible skin;

The flexible trailing edge structure 1 consists of eight rigid segments 4 that are hinged in sequence, which together with the leading edge rigid segment 2 are integrally formed to approximate a dinosaur-like coccyx structure; each rigid segment from the leading edge rigid segment 2 to the flexible trailing edge structure 1 , following the method of decreasing size in turn, so that the entire wing forms a smooth airfoil surface;

The structural features of each rigid segment 4 of the flexible trailing edge structure 1 are: its main body is a rectangular shell, and a front end bump 10 protrudes outward from the surface of each rigid segment adjacent to the previous adjacent rigid segment. The side with the next adjacent rigid segment is missing, so that the inner cavity of the rectangular housing of the rigid segment just accommodates the front end bump 10 of the next adjacent rigid segment; each rigid segment is connected to the front end convex of the next adjacent rigid segment. The blocks 10 are connected by through cylindrical pins 12 to form a way of hingedly connecting a plurality of rigid segments in sequence; on the upper and lower inner walls of the rigid segment housing, there are 10 fine grooves 9 parallel to each other along the spanwise direction. , the size and position of the thin grooves of each rigid segment are corresponding, so that after all the rigid segments are hinged in turn, the thin grooves 9 are connected to 10 through grooves throughout the entire flexible trailing edge structure, and 10 shape memory alloy wires are placed in the In the 10 through grooves, their two ends are respectively fixed to the alloy wire fixing grooves 5 of the flexible trailing edge structure 1 along the chordwise direction of the airfoil. The diameter of the shape memory alloy wire used in this embodiment is 0.15mm, and the tensile force provided by a single wire according to the test is about 2N.

In order to better modularize the deformed wing structure, in this embodiment, more than three groups of deformed wing structures are provided with mutually matching bumps 8 and grooves in the spanwise direction to form a modular assembly. In actual use, a group of deformed wing structures in the middle do not use shape memory alloy wires, but are only hinged rigid segment structures, while the two sets of deformed wing structures on both sides provide a hinged rigid segment structure driven by shape memory alloy wires. , so that the wings form a modular continuous assembly method of active 14, passive 13, and active 14.

In order to make the deformed wing structure generate less resistance during deformation, in this embodiment, a reversing structure is added from the rigid section of the leading edge to the flexible trailing edge structure (Fig. 6), so that when the wing is deformed upward or downward, the lower Side or upper chord length. The reversing mechanism mainly includes an upper sliding piece 15, a lower sliding piece 16, an electromagnet mounting block 17, a spring preload transition block 18, a spring group and a limit block 19; the upper sliding piece 15 and the lower sliding piece 16 are installed in parallel and correspondingly, The upper sliding piece 15 and the lower sliding piece 16 are respectively provided with an upper card slot 20 and a lower card slot 21; the electromagnet mounting block 17 is installed with a miniature self-sustaining push-pull electromagnet, and the entire electromagnet mounting block is located between the upper and lower sliding plates. Between the sheet 15 and the lower sheet 16, a miniature self-sustaining push-pull electromagnet controls a core pin to switch in the upper slot 20 or the lower slot 21;

Two upper and lower grooves are respectively opened on the side wall of the connection between the spring preloading transition block connected to the wing and the deformation section. When the two are butted, the two grooves are respectively connected to form upper and lower through grooves 22 . ;

After the reversing mechanism is installed, it is fixed inside the shell at the connection between the wing fixed section and the deformed section, and the upper sliding piece 15 and the lower sliding piece 16 of the reversing mechanism are respectively in the upper and lower parts formed by the wing fixed section and the deformed section. The through slot 22 can slide freely; the spring group of the reversing mechanism includes 5 parallel and symmetrical springs, one end of which is fixed on the end face of the upper sliding piece 15 or the lower sliding piece 16, and the other end is fixed on the machine through the spring preload transition block 18. Inside the fixed section of the wing, it is used to provide a certain pre-tightening force to offset the lateral force transmitted from the deformation section to the electromagnet locking pin through the sliding piece, thereby improving the stability of the reversing mechanism; the limit block 19 of the reversing mechanism is placed in The front end of the wing deformation section ensures the sliding limit of the upper sliding piece 15 and the lower sliding piece 16 in the spanwise direction.

If the trailing edge of the wing needs to be deflected upward, first release the electromagnet core latch by energizing the electromagnet that controls the lower side slider, so that the lower side slider is in a free sliding state, and then the shape memory alloy arranged on the upper side is energized. When the wire is heated, the alloy wire will deform and provide a certain driving force to drive the trailing edge of the wing to deflect upward. Due to the relative increase in the chord length of the lower wing, it will drive the unlocked slide on the lower side to slide, thereby completing the wing. The movement of the trailing edge deflecting upwards; when deflecting downwards, first release the electromagnet core pin by energizing the electromagnet that controls the upper sliding piece, so that the upper sliding piece is in a free sliding state, and the lower sliding piece is controlled. The electromagnet is reversely energized to pop out the iron core bayonet to lock the lower sliding piece, and then heat the shape memory alloy wire arranged on the lower side. At this time, the alloy wire will deform and provide a certain driving force to drive the trailing edge of the wing. Downward deflection, due to the relative increase in the chord length of the upper wing, will drive the upper unlocked slide to slide, thereby completing the downward deflection of the trailing edge of the wing.

Claims (3)

1. The deformed wing structure driven by the two-way shape memory alloy comprises a flexible trailing edge structure (1) coated by a flexible skin and a leading edge rigid section (2); the method is characterized in that:

the flexible rear edge structure (1) is formed by sequentially hinging a plurality of rigid sections (4), and the flexible rear edge structure and the front edge rigid section (2) form an approximate dinosaur-like coccyx structure integrally; each rigid section (4) from the front edge rigid section (2) to the flexible rear edge structure (1) follows the mode of sequentially reducing the size, so that the whole wing forms a smooth wing surface;

each rigid section (4) of the flexible trailing edge structure (1) is structurally characterized in that: the main body of the device is a rectangular shell, a front end bump (10) protrudes outwards from the surface of each rigid section adjacent to the previous adjacent rigid section, and an internal cavity is formed on the surface of each rigid section adjacent to the next rigid section, so that the internal cavity of the rectangular shell of the rigid section just accommodates the front end bump (10) of the next adjacent rigid section; each rigid section is connected with a front end bump (10) of the next adjacent rigid section through a through cylindrical pin (12) to form a mode that a plurality of rigid sections are sequentially hinged; a plurality of parallel thin grooves (9) along the wingspan direction are formed in the upper inner wall surface and the lower inner wall surface of the rigid section shell, the size and the position of each thin groove (9) of each rigid section (4) are corresponding, after all the rigid sections (4) are sequentially hinged, the thin grooves (9) are sequentially communicated with a plurality of through grooves penetrating through the whole flexible trailing edge structure, a plurality of shape memory alloy wires with corresponding number are arranged in the through grooves, and the alloy wires are fixed at alloy wire fixing ends (5) of the flexible trailing edge structure along the chord direction of the wing profile.

2. A two-way shape memory alloy actuated morphing wing structure according to claim 1, wherein a commutating structure is added between the flexible trailing edge structure (1) to the leading edge rigid section (2) to increase the lower or upper chord length as the wing is morphed up or down.

3. The two-way shape memory alloy driven morphing wing structure is characterized in that a plurality of groups of morphing wing structures according to claim 1 are formed by arranging modular assembling structures in the spanwise direction of an airfoil.

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