CN114313215A - Wing tip structure with variable inclination angle and height - Google Patents

Abstract

The invention discloses a wing tip structure with variable inclination angle and height, comprising a left wing rib, a driving mechanism, a deformation mechanism, a flexible skin, a right wing rib and a support structure; the left wing rib is clamped at 0°-90° The corner is installed on the main wing, the left wing rib is connected with the driving mechanism, the driving mechanism is connected with the deformation mechanism, and the deformation mechanism is connected with the right wing rib; the driving mechanism is used to drive the deformation mechanism to deform, changing the right wing rib relative to the left wing The spatial position of the rib; the two sides of the left rib and the right rib are connected by a support structure; a flexible skin is covered and installed on the support structure to form a closed aerodynamic shape. The deformation mechanism of the present invention adopts a plane linkage mechanism, which realizes the continuous elongation, shortening and bending of the wingtip structure, effectively improves the aerodynamic performance and maneuvering performance of the aircraft, improves the lift coefficient of the wingtip, reduces the induced resistance, and adapts to different flight environments. Requirements for aerodynamic shape.

Description

A variable pitch and height wingtip structure

technical field

The invention relates to the field of aerospace inter-aircraft, in particular to a wing tip structure with variable inclination and height.

Background technique

Since the Wright Brothers invented the first airplane and human beings realized the dream of flying, airplanes have played an important role in human society. However, in the early design process of aircraft, the wingtips were often fixed, and their aerodynamic characteristics were often optimized according to a single purpose or a compromise design optimization according to multiple flight environments. Adjust the flight status to achieve optimal flight performance. However, with the continuous improvement of various requirements for the flight efficiency, aerodynamic performance, maneuverability and multi-tasking of aircraft, especially the development of UAV technology, the disadvantages of traditional fixed-wing aircraft have gradually become prominent.

Relevant aerodynamic studies have shown that the airfoil can effectively improve the aerodynamic characteristics of the aircraft according to the changes of different flight environments. Variable flex wingtips can improve maneuverability, reduce induced drag, and improve stall performance. K.K.Ishimitus of Boeing Company of the United States installed fixed winglets on the air tanker for the first time. The experimental results showed that the drag was reduced by 7.2%, the lift-to-drag ratio was increased by 8%, and the fuel consumption was reduced by 9%. At present, the wingtip has been widely adopted, but the wingtip geometry is only designed for cruise, and the drag reduction efficiency in the take-off and climb phases is low. Zuo Linxuan et al. found that the unilateral deformation of the variable pitch wingtip structure can significantly increase the yaw moment and pitch moment, and improve the maneuverability of the aircraft. Li Wei from Nanjing University of Aeronautics and Astronautics has studied the variable-height wingtip structure, and the results show that it can significantly improve the wingtip wake vortex strength and improve the wing lift coefficient. The continuously variable wingtip structure during flight has broad application prospects.

In terms of variable wing tip inclination, P. Bourdin et al. adopted the design of a servo motor-driven linkage mechanism to change the wing tip inclination. In addition, Boeing also proposed a shape memory alloy-driven torsion tube structure to change the wing tip pitch. Chinese patent application CN201920779634.X discloses a novel wingtip variable inclination structure that bends a multi-end wing through a piezoelectric fiber driver. Li Qiang and others of AVIC used an eccentric crank-slider mechanism, which was driven by a connecting rod to drive the wingtip to rotate to change the inclination. In terms of changing the wing tip height, Li Wen et al. designed a retractable structure driven by a steel cable winch, which retracts a section of the wing into the main wing in advance, and realizes the continuous change of the retractable wing through the winch. Li Wei of Nanjing University of Aeronautics and Astronautics designed a differential telescopic grid mechanism. Two sets of telescopic grids are connected in parallel. By controlling the movement of the two sets of telescopic grids respectively, the change of the wing tip inclination and height can be achieved, but it requires two a motor drive. At present, most of the deformable wing tips are only designed for a single deformation mode, and there are few designs that can perform two deformation modes at the same time, and they face the problem of weight.

The skin is mainly responsible for continuous deformation, maintaining aerodynamic shape and maintaining airtightness in the variant aircraft. Traditional skin materials are made of metal or composite materials, which have little ability to deform. With the in-depth exploration of variant aircraft, a large number of flexible skins have been designed and studied. There are mainly corrugated structure skins, honeycomb structure skins, fish scale structure skins, rubber skins and composite structure skins based on smart materials such as memory alloys. Most of the current flexible skins can only achieve single-curvature stretching and bending deformation, or small-scale double-curvature deformation such as torsional deformation. When bending occurs in the spanwise direction of the wing tip or at the wing tip, since the skin itself has been bent in the chord length direction, the skin needs to be able to achieve double curvature bending, that is, bending in the direction perpendicular to the chord length at the same time. At the same time, it is also necessary to prevent the skin from wrinkling, keep it smooth and have a certain bearing capacity, and the design of this skin structure is less.

In summary, the continuously variable wingtip structure during flight has broad application prospects. Most of the current deformable wingtips are only designed for one deformation mode, and there are few designs that can carry out two deformation modes at the same time, and face problems such as heavy weight, difficult control, and complex structure. At the same time, it is not a small challenge to realize the skin structure design with double curvature continuous smooth bending and certain bearing capacity.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a deformable wingtip structure with variable inclination and height, while maintaining a smooth and continuous appearance, thereby effectively improving the maneuverability, flight efficiency and multi-task adaptability of the aircraft.

The purpose of this invention is to realize through the following technical solutions:

A wing tip structure with variable inclination and height, comprising a left wing rib, a driving mechanism, a deformation mechanism, a flexible skin, a right wing rib and a support structure; the left wing rib is at an included angle of 0°-90° Installed on the main wing, the left wing rib is connected with the driving mechanism, the driving mechanism is connected with the deformation mechanism, and the deformation mechanism is connected with the right wing rib; the driving mechanism is used to drive the deformation mechanism to deform, and change the right wing rib relative to the left side. The spatial position of the wing rib; the two sides of the left wing rib and the right wing rib are connected by a support structure; the support structure is covered and installed with a flexible skin to form a closed aerodynamic shape;

The drive mechanism includes a motor, a drive gear, an upper gear, an upper camshaft, a lower gear and a lower camshaft; the motor is mounted on the main wing, and the output shaft of the motor is connected to the drive gear through the left wing rib; The drive gear meshes with the upper gear and the lower gear to form a fixed-axis gear train; the upper camshaft is connected to the upper gear through a key, and the lower camshaft is connected to the lower gear through a key; the upper camshaft and the lower camshaft are connected to the deformation mechanism;

The deformation mechanism includes an upper push rod, a lower push rod, an upper connecting rod, a lower connecting rod and a slider, and the deformation mechanism has two degrees of freedom; one end of the upper push rod is connected to the upper camshaft, and the other end is hinged to the upper connecting rod Middle; one end of the lower push rod is connected to the lower camshaft, and the other end is hinged to the middle of the lower link; the upper push rod and the lower push rod are parallel to each other; the end of the lower link is hinged to the slider, and the slider is connected to the end of the upper link; The top of the rod is hinged above the right rib, and the top of the lower link is hinged below the right rib;

Further, the motor drives the upper gear and the lower gear to rotate, thereby driving the upper camshaft and the lower camshaft to rotate, and the upper camshaft and the lower camshaft are provided with a helical wire groove, which pushes the upper push rod and the lower push rod in a screw transmission manner. The rod moves in a straight line, thereby changing the mutual position of the upper link and the lower link, and then continuously changing the spatial position and posture of the right wing rib to achieve the purpose of deformation.

Further, the spiral groove is designed by the reversal method; when the spatial position of the right wing rib relative to the left wing rib is known to change, the relationship between the upper push rod and the lower push rod is calculated through experiments or mechanism kinematics analysis. Running track, so as to reversely design the cylindrical cam helical groove.

Further, when the helical grooves of the upper camshaft and the lower camshaft are the same, the wing tips can be extended and shortened; when the helical grooves of the upper camshaft and the lower camshaft are opposite, the wing tips can be bent upwards. Or bend downward; according to different combinations of spiral grooves, several deformations can be realized.

Further, the flexible skin is composed of a helical skeleton structure and an elastic matrix; the helical skeleton structure is buried inside the elastic matrix; It has bearing capacity; the helical skeleton structure has the effect of deformation constraint and matrix reinforcement on the elastic matrix, preventing the elastic matrix from wrinkling during the deformation process.

Further, the elastic matrix is made of rubber or shape memory polymer material; when a material such as rubber is used that is difficult to drive actively, the flexible skin can be passively deformed according to the wing tip; when a shape memory polymer is used, the flexible skin can be added Under the action of the physical field, it is actively deformed to meet the requirements of the aerodynamic shape of the wing under different flight missions.

Further, the supporting structure is a double-corrugated structure based on origami, and the basic unit of the supporting structure is formed by two kinds of origami units that are folded according to the mirrored valley line distribution and spliced up and down; The basic unit can bear the aerodynamic load in the longitudinal direction, and can continuously bend and stretch in the axial direction.

Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

1. In the present invention, the deformation mechanism adopts a plane linkage mechanism, which realizes the continuous elongation, shortening and bending of the wingtip structure, effectively improves the aerodynamic performance and maneuvering performance of the aircraft, improves the lift coefficient of the wingtip, reduces the induced resistance, and adapts to different The requirements of the flight environment for aerodynamic shape.

2. In the present invention, the drive mechanism of the cylindrical cam is used to drive the deformation mechanism. The cylindrical cam can be reversely designed according to the deformation mode of the wingtip, which expands the deformation mode of the wingtip and improves the multi-tasking and maneuverability of the aircraft. And through the deformation mechanism driven by a single motor, the weight of the wing tip is reduced, the structure is simple, the rigidity is good, and the reliability is high.

3. The flexible skin designed in the present invention embeds the helical skeleton structure into the elastic matrix, realizes the elongation, shortening, bending and torsional deformation of the flexible skin, and can conform to the diverse deformation modes of the wingtip. It has smooth deformation, good flexibility, simple structure, light weight and certain bearing capacity, and has broad application prospects in the field of variant aircraft.

4. The support structure designed in the present invention is a double corrugated structure based on origami, which is characterized in that the rigidity in the longitudinal direction is large to bear the aerodynamic load, but it is compliant in the axial direction, which can realize bending and elongation deformation, and has a light weight. Features.

5. In the present invention, the helical grooves on the camshaft can be designed by the reversal method; in addition, when the helical grooves of the upper camshaft and the lower camshaft are the same, the wing tips can be extended and shortened. When the helical grooves of the upper camshaft and the lower camshaft are opposite, the wing tip can be bent upward or downward. At the same time, different combinations of helical grooves can achieve more complex deformation.

6. In the present invention, the flexible skin is a skeleton-reinforced elastomer. The helical skeleton structure can achieve elongation and bending deformation in the axial direction, has strong deformation ability and various deformation modes, and has bearing capacity in the longitudinal direction. The spiral skeleton structure has deformation restraint and matrix strengthening effect on the wrapped elastic matrix, preventing the elastic matrix from wrinkling during the deformation process. The spiral skeleton structure can be made of metal or non-metal materials such as manganese steel and 7075 aluminum alloy with good elasticity and high yield strength.

7. The supporting structure is a double-corrugated structure based on origami, and its basic unit is composed of two kinds of origami units that are folded according to a specific valley line distribution and spliced up and down. The basic unit is expanded in three dimensions and cut according to the shape of the rib. The rigidity in the longitudinal direction is very large to bear the aerodynamic load, but it is compliant in the axial direction and can realize deformation such as bending and stretching. Its main purpose is to make up for the insufficient bearing capacity of flexible skins under high aerodynamic loads without hindering deformation.

Description of drawings

Figure 1 is a side view of the wing tip structure of the present invention.

Figure 2 is a schematic view of the shape of the wing tip before deformation in the present invention.

3 is a schematic diagram of the shape of the wing tip changing height in the present invention.

FIG. 4 is a schematic diagram of the shape of the wing tip bent upward in the present invention.

FIG. 5 is a schematic diagram of the shape of the wing tip bent downward in the present invention.

FIG. 6 is a schematic structural diagram of the deformation mechanism in the present invention.

Figure 7 is a side view of the drive mechanism in the present invention.

FIG. 8 is a schematic diagram of the structure of the fixed axle gear train in the present invention.

Figure 9 is a side view of the push rod in the present invention.

Figure 10 is a right side view of the push rod in the present invention.

11 is a cross-sectional view of the flexible skin structure in the present invention.

12 is a schematic diagram of the flexible skin helical skeleton structure in the present invention before deformation and a schematic diagram of the cross-sectional structure along the A-A direction.

13 is a schematic diagram of the elongated configuration of the flexible skin helical skeleton structure and a schematic diagram of the cross-sectional structure along the B-B direction in the present invention.

14 is a schematic diagram of the bending configuration of the flexible skin helical skeleton structure in the present invention and a schematic diagram of a C-C cross-sectional structure.

Figure 15 is the basic unit of the double corrugated structure based on origami in the present invention.

Figure 16 is a side view of the expanded configuration of the basic unit of the origami-based double-corrugated structure of the present invention.

Figure 17 is a schematic diagram of the filling configuration of the origami-based double-corrugated structure in the present invention.

18 is a schematic diagram of the bending of the double-corrugated structure based on origami in the present invention and a schematic diagram of the cross-sectional structure along the E-E direction.

Reference numerals: 1-left rib, 2-drive mechanism, 3-deformation mechanism, 4-flexible skin, 5-support structure, 21-motor, 22-drive gear, 23-upper gear, 24-upper cam Shaft, 25-lower gear, 26-lower camshaft, 31-upper push rod, 32-upper link, 33-lower pushrod, 34-lower link, 35-slider, 36-right rib, 41 - Spiral skeleton structure, 42- elastic base, 51- origami unit, 52- origami unit.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

As shown in FIGS. 1-10 , a wing tip structure with variable inclination and height includes a left wing rib 1 , a drive mechanism 2 , a deformation mechanism 3 , a flexible skin 4 and a support structure 5 . The left wing rib 1 is installed on the main wing at a certain angle, and the drive mechanism 2 is fixed on the left wing rib 1 to drive the deformation mechanism 3 to deform, changing the spatial position of the right wing rib relative to the left wing rib 1 . The flexible skin 4 covers the outside of the entire wingtip, maintaining a smooth, compliant and closed aerodynamic shape. The support structure 5 is placed under the flexible skin to strengthen the load-bearing capacity of the flexible skin 1 while maintaining the deformability.

As shown in FIG. 3 , the driving mechanism includes a motor 21 , a driving gear 22 , an upper gear 23 , an upper camshaft 24 , a lower gear 25 and a lower camshaft 26 . The drive gear 22 is fixed to the motor output shaft. The motor 21 is installed on the main wing, and the output shaft of the motor 21 is connected to the drive gear 22 through the left wing rib 1 ; the motor 21 , the upper gear 23 and the lower gear 25 are fixed to the left wing rib 1 . The drive gear 22, the upper gear 23 and the lower gear 25 form a fixed-axis gear train. The upper camshaft 24 is connected to the upper gear 23 by a key, and the lower camshaft 26 is connected to the lower gear 25 by a key. The upper camshaft 24 and the lower camshaft 26 are connected with the deformation mechanism.

As shown in FIG. 3 , the deformation mechanism includes an upper push rod 31 , a lower push rod 33 , an upper link 32 , a lower link 34 , a slider 35 and a right wing rib 36 , and the degree of freedom is 2. One end of the upper push rod 31 is connected to the upper camshaft 24 , and the other end is hinged to the middle of the upper link 32 . One end of the lower push rod 33 is connected to the lower camshaft 26 , and the other end is hinged to the middle of the lower link 34 . The upper push rod 31 and the lower push rod 33 are parallel to each other. The end of the lower link 34 is hinged to the slider 35 , and the slider 35 is connected to the upper link 32 . The top end of the upper link 32 is hinged above the right wing rib 36 , and the top end of the lower link 34 is hinged below the right wing rib 36 .

In the present invention, the upper gear 23 and the lower gear 25 are driven by the motor 21 to rotate, thereby driving the upper camshaft 24 and the lower camshaft 26 to rotate. way to push the upper push rod 31 and the lower push rod 33 to do linear motion, thereby changing the mutual position of the upper link 32 and the lower link 34, the top of the upper link 32 and the lower link 34 are hinged to the right wing rib 36, and then change The spatial position and posture of the right wing rib 36 are used to achieve the purpose of deformation.

Further, the helical grooves on the upper camshaft 24 and the lower camshaft 26 can be designed by the reverse method. When the spatial position of the right side rib 36 relative to the left side rib 1 is known, the running trajectories of the upper push rod 31 and the lower push rod 33 can be calculated through experiments or mechanism theory, so as to reversely design the upper camshaft 24 and the lower push rod 33 . The upper helical groove of the lower camshaft 26 is provided.

Further, when the helical grooves of the upper camshaft 24 and the lower camshaft 26 are the same, the blade tip can be elongated in the extension direction, as shown in FIG. 3 . When the helical grooves of the upper camshaft 24 and the lower camshaft 26 are opposite, the wing tips can be bent upward or downward, as shown in FIGS. 4-5 . At the same time, different combinations of helical grooves can achieve more complex deformation.

As shown in FIGS. 11-14 , in this embodiment, the flexible skin 4 is a skeleton-reinforced elastic body. The spiral skeleton 41 structure can achieve elongation and bending deformation in the axial direction, has strong deformation ability and various deformation modes, and has a certain bearing capacity in the longitudinal direction. The structure of the helical skeleton 41 has the deformation restraint and matrix strengthening effect on the wrapped elastic matrix 42 to prevent it from wrinkling during the deformation process. The structure of the spiral skeleton 41 can be made of metal or non-metal materials such as manganese steel and 7075 aluminum alloy with good elasticity and high yield strength.

Further, the elastic matrix 42 can be selected from a rubber-like material with a high elastic limit and a low Young's modulus, which can generate a large deformation under a small driving force. The formed flexible skin 4 is passively deformed according to the wingtip, so as to meet the requirements of aerodynamic shape under different flight missions.

Further, the support structure 5 is an origami-based double corrugated structure. As shown in FIG. 15 , the basic unit is formed by folding the origami unit 51 and the origami unit 52 according to a specific valley line distribution and splicing up and down, wherein the solid line represents the mountain line, and the dashed line represents the valley line. The basic unit is expanded in the three-dimensional direction, and its expanded configuration is shown in Figure 16. The expansion structure is cut according to the shape of the wing rib and fills the interior of the wing tip as a filler. It can be formed by 3D printing or surface-to-surface bonding. It is characterized in that it has great rigidity in the longitudinal direction to bear the aerodynamic load, but is compliant in the axial direction and can realize deformation such as bending. Its initial filling configuration is shown in Figure 17, and its curved configuration is shown in Figure 18.

The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention, and the above-mentioned specific embodiments are only illustrative and not restrictive. Without departing from the spirit of the present invention and the protection scope of the claims, those of ordinary skill in the art can also make many specific transformations under the inspiration of the present invention, which all fall within the protection scope of the present invention.

Claims (7)

1. a wing tip structure with variable inclination angle and height, it is characterized in that, comprise left wing rib, drive mechanism, deformation mechanism, flexible skin, right wing rib and support structure; Described left wing rib with 0 It is installed on the main wing at an angle of °-90°, the left rib is connected with the driving mechanism, the driving mechanism is connected with the deformation mechanism, and the deformation mechanism is connected with the right rib; the driving mechanism is used to drive the deformation mechanism to deform and change the right side. The spatial position of the wing rib relative to the left wing rib; the two sides of the left wing rib and the right wing rib are connected by a support structure; the support structure is covered and installed with a flexible skin to form a closed aerodynamic shape; The drive mechanism includes a motor, a drive gear, an upper gear, an upper camshaft, a lower gear and a lower camshaft; the motor is mounted on the main wing, and the output shaft of the motor is connected to the drive gear through the left wing rib; The drive gear meshes with the upper gear and the lower gear to form a fixed-axis gear train; the upper camshaft is connected to the upper gear through a key, and the lower camshaft is connected to the lower gear through a key; the upper camshaft and the lower camshaft are connected to the deformation mechanism; The deformation mechanism includes an upper push rod, a lower push rod, an upper connecting rod, a lower connecting rod and a slider, and the deformation mechanism has two degrees of freedom; one end of the upper push rod is connected to the upper camshaft, and the other end is hinged to the upper connecting rod Middle; one end of the lower push rod is connected to the lower camshaft, and the other end is hinged to the middle of the lower link; the upper push rod and the lower push rod are parallel to each other; the end of the lower link is hinged to the slider, and the slider is connected to the end of the upper link; The top end of the rod is hinged above the right wing rib, and the top end of the lower link is hinged below the right wing rib. 2. a kind of wing tip structure with variable inclination and height according to claim 1 is characterized in that, the upper gear and the lower gear are driven to rotate by the motor, thereby driving the upper camshaft and the lower camshaft to rotate, the upper camshaft and The lower camshaft is provided with a helical groove, which pushes the upper push rod and the lower push rod to move in a straight line by means of helical transmission, thereby changing the mutual position of the upper connecting rod and the lower connecting rod, and then continuously changing the space position and the space position of the right wing rib. posture to achieve the purpose of deformation. 3. A wing tip structure with variable inclination and height according to claim 2, characterized in that, the spiral groove is designed by a reversal method; When the spatial position changes, the running trajectories of the upper push rod and the lower push rod are calculated through experiments or kinematic analysis of the mechanism, so as to reversely design the cylindrical cam helical groove. 4. A wing tip structure with variable inclination and height according to claim 2, characterized in that, when the helical grooves of the upper camshaft and the lower camshaft are the same, the wing tip can be elongated and shortened; When the spiral grooves of the upper camshaft and the lower camshaft are opposite, the wing tip can be bent upward or downward; according to different combinations of the spiral grooves, several deformations can be realized. 5 . The wingtip structure with variable inclination and height according to claim 1 , wherein the flexible skin is composed of a spiral skeleton structure and an elastic matrix; the spiral skeleton structure is buried inside the elastic matrix; the spiral skeleton The structure can achieve elongation, shortening, bending and torsional deformation in the axial direction, and has bearing capacity in the longitudinal direction; the helical skeleton structure has deformation constraints and matrix strengthening effects on the elastic matrix, preventing the elastic matrix from wrinkling during the deformation process. 6. The wing tip structure with variable inclination and height according to claim 5, wherein the elastic matrix is selected from rubber or shape memory polymer material; The skin can be passively deformed according to the wing tip; when a shape memory polymer is selected, the flexible skin can be actively deformed under the action of an external physical field to meet the aerodynamic shape requirements of the wing under different flight missions. 7 . The wing tip structure with variable inclination and height according to claim 1 , wherein the supporting structure is a double corrugated structure based on origami, and the basic unit of the supporting structure is composed of two kinds of origami units according to the mirrored valleys. 8 . The lines are folded and spliced up and down; the basic unit is expanded in the three-dimensional direction and cut according to the shape of the rib; the basic unit can bear the aerodynamic load in the longitudinal direction, and can continuously bend and stretch in the axial direction.

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