Wingtip turning mechanism for morphing aircraft

Abstract

The invention belongs to the technical field of morphing aircrafts, and discloses a connecting rod type mechanism for wing tip turning of a morphing aircraft. Comprising a double-four-rod symmetrical movement mechanism, a driving rod and a driving unit of the driving rod, wherein the double-four-rod symmetrical movement mechanism consists of a vertical rod, an inclined long rod and an inclined short rod, and two sides of the vertical rod are connected with wing ribs. Two or more connecting rod mechanism modules can be connected in parallel, and single drive is achieved through one rigid rod. The driving element transmits force to the vertical rod on the right side through the driving rod to achieve mechanism turning, and the rotation center is located on the outer side of all the movable mechanisms, so that upper and lower skins of a turning section of the wing are both pulled in the turning process, the skin wrinkling or swelling phenomenon is avoided, and the phenomenon that wingtip deformation and pneumatic discontinuity are easily solved.

Description

Technical Field

[0001] The present invention relates to the technical field of morphing aircraft, and in particular to a wing tip folding mechanism for a morphing aircraft. Background Art

[0002] The wingtip deformation of the morphing aircraft wing can adjust its aerodynamic performance and reduce noise at different flight stages, so that the aerodynamic efficiency in the entire envelope can be improved by 3%-5%, and the dynamic characteristics (flutter behavior) of the wing can be improved, and the wingtip vortex of the aircraft can be reduced. Therefore, the morphing wingtip can greatly improve the flight characteristics of the aircraft. At the same time, in the aircraft structure design, reducing the aircraft drag is an effective way to reduce fuel consumption and save operating costs, and the inclination angle parameter of the wingtip winglet has the greatest drag reduction effect. The wingtip fold can change the geometric shape parameters in real time according to the flight state, so that it can provide the aircraft with the best drag reduction effect in the entire flight envelope. Among them, the flexible skin is an indispensable component of the large deformation wing surface. However, in the upward deflection process of the aircraft winglet of the general structure, because the center of rotation exists between the upper and lower surfaces of the wing, the upper skin is easily squeezed and wrinkled or bulged due to the extrusion force, resulting in the wing cannot be smoothly deformed, thereby destroying the continuity of the wing surface and increasing the induced drag. At present, the solutions to the skin wrinkles are mostly considered from the skin material itself, and rarely involve the deformation mechanism. Summary of the invention

[0003] The purpose of the present invention is to propose a wingtip folding mechanism for a morphing aircraft. The wingtip folding mechanism is a connecting rod type folding mechanism with a rotation center outside the mechanism, so that the upper and lower skins are both subjected to tension, avoiding the occurrence of wrinkles or bulging of the skin, and providing a new option for folding the wingtips of the morphing aircraft.

[0004] The technical solution of the present invention is as follows: a wingtip folding mechanism for a deformable aircraft, comprising a driving unit 1, a driving rod 2, a vertical rod 3, an oblique short rod 4 and an oblique long rod 5; the vertical rod 3 is arranged in a single group or multiple groups, including a fixed vertical rod and a movable vertical rod; the fixed vertical rod is installed on the fixed wing or the large wing side, and the movable vertical rod is installed on the small wing side to drive the outer wing to fold; the driving unit 1 is connected to one end of the driving rod 2, and the other end of the driving rod 2 is connected to the movable vertical rod to drive it to move and drive the outer wing to fold; the fixed vertical rod and the movable vertical rod in the same group are connected through the oblique short rod 4 and the oblique long rod 5.

[0005] Furthermore, the oblique short rod 4 and the oblique long rod 5 are inside the fixed vertical rod and the movable vertical rod; one end of the oblique short rod 4 is connected to the lower end point of the vertical rod 3 of the same group, one end of the oblique long rod 5 is connected to the upper end point of the vertical rod 3 of the same group, and the other end of the oblique short rod 4 is connected to the other end of the oblique long rod 5.

[0006] Furthermore, two oblique long rods 5 connecting the same group of vertical rods 3 intersect at an intersection.

[0007] Furthermore, the oblique short rod 4 connected to the fixed vertical rod is connected to the oblique long rod 5 connected to the movable vertical rod; the oblique long rod 5 connected to the fixed vertical rod is connected to the oblique short rod 4 connected to the movable vertical rod.

[0008] Furthermore, the wingtip folding mechanism for the transformable aircraft is a connecting rod mechanism, and each rod is connected by a pin shaft; when the driving unit 1 moves horizontally, the fixed vertical rod remains stationary, and the movable vertical rod is driven by the driving rod 2 to fold upward; during the folding process, the fixed vertical rod and the movable vertical rod are in a non-parallel state, and there is always an intersection between the two located outside the mechanism, which is the rotation center of the movable wing side.

[0009] Furthermore, the wingtip folding mechanism for the deformable aircraft is connected to different groups of vertical rods 3 via a rigid shaft 6 to arrange multiple groups of mechanisms in a linear array.

[0010] Furthermore, the plurality of groups of mechanism linear arrays are arranged as follows: the driving rod 2 is connected to the middle of the rigid shaft 6 , and the movable vertical rods in different groups of vertical rods 3 are connected to the rigid shaft 6 , and are evenly distributed on both sides of the driving rod 2 .

[0011] Furthermore, the wingtip folding mechanism for the morphing aircraft has 1 degree of freedom. When the input motion is determined, the wingtip folding mechanism for the morphing aircraft has a uniquely determined output folding motion.

[0012] Beneficial effects of the present invention:

[0013] (1) The present invention can be regarded as a deformation unit. Combined with the wing shape, two or more deformation units can be connected in parallel to make the wing folding more stable and the force more uniform.

[0014] (2) The center of rotation of the present invention is outside the mechanism, so that the skin of the folding section is subjected to tension both above and below, thereby avoiding the discontinuity of the aerodynamic shape caused by wrinkles and bulging of the skin.

[0015] (3) The parallel design of the present invention can be connected to the driving rod through a rigid rod, and the driving rod is connected to the rigid rod to achieve a single driving purpose. Multiple groups of mechanisms are set in parallel according to the wing size and are evenly distributed on both sides of the drive.

[0016] (4) The present invention can design the size parameters of each connecting rod according to the required folding angle combined with the airfoil size, but the mechanism can achieve the folding purpose. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the mechanism motion, (a) before motion deformation, (b) after motion deformation, P is the rotation center of the mechanism.

[0018] Figure 2 It is a schematic diagram of parallel connection of mechanisms.

[0019] Figure 3 It is a schematic diagram of the deformation of the folding wing.

[0020] Figure 4 Agency flat vector illustration.

[0021] Figure 5 It is a graph showing the relationship between the input value S and the change in the folding rib angle. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0023] A wingtip folding mechanism for a morphing aircraft comprises a driving unit 1, a driving rod 2, a vertical rod 3, an oblique short rod 4 and an oblique long rod 5; the vertical rod comprises a fixed vertical rod and a movable vertical rod, wherein the fixed vertical rod is installed on the fixed wing or the large wing side, and the movable vertical rod is installed on the small wing side to drive the outer wing to fold; the oblique short rod 4 and the oblique long rod 5 are inside the fixed vertical rod and the movable vertical rod; the driving rod 2 is connected to the driving.

[0024] The mechanism is a connecting rod mechanism, and each connecting rod is connected by a pin. 1 is a driving unit, and the driving unit 1 moves horizontally to the right, and drives the right movable vertical rod to fold upward through the driving rod 2. During the folding process, the fixed vertical rods and the movable vertical rods on the left and right sides always have an intersection located outside the mechanism, which can be the rotation center of the wing side.

[0025] The mechanism can be arranged in a linear array of multiple groups of mechanisms through a rigid shaft 6, making the wing folding more stable. At the same time, the parallel arrangement can weaken the gap existing when the pin shafts between the connecting rods are connected and the influence of the assembly accuracy.

[0026] The above-mentioned wingtip folding mechanism for a morphing aircraft of the present application has an ideal mechanism degree of freedom of 1, that is, when the input motion is determined, the mechanism has a uniquely determined output folding motion.

[0027] like Figure 1 As shown in (a), the present invention is a wing tip folding mechanism for a morphing aircraft, which is regarded as a planar mechanism, including an AB rod, a BC rod, an AE rod, a CG rod, an EF rod, a FG rod, a BH rod and a drive unit H. The AB rod is connected to the outer wing folding rib; the GF rod is fixed and connected to the inner wing rib; the short oblique rod BC is the same as EF, and the long oblique rod AE is the same as CG, which are hinged through an internal hinge hole D; and the BH rod is connected to the drive.

[0028] like Figure 1 As shown in (a), in the initial position, the GF rod is fixed vertically, the AB rod is vertical, and the driving unit H moves horizontally to the right and drives the AB rod to fold upward through the BH rod. Figure 1(b). During the folding process, the fixed and movable vertical rods on the left and right sides always have an intersection point P located outside the mechanism, which is the rotation center of the wing side. This increases the chord lengths AG and BF of the deformed wing during the upward folding process, ensuring that the upper and lower surface skins of the wing are stretched to avoid wrinkles.

[0029] Calculate the degree of freedom of the mechanism. The formula for calculating the degree of freedom of the planar mechanism is:

[0030] F=3n-(2P L +P H ) (1)

[0031] Among them, F represents the number of degrees of freedom of the mechanism, n represents the number of active components, and P L Represents the number of low pairs, P H Represents the number of high pairs, in this mechanism n = 7, P L =7,P H = 0. Therefore, the solution to the number of degrees of freedom of the planar mechanism is

[0032] F = 3 × 7 - (2 × 10 + 0) = 1 (2)

[0033] Calculated by the formula, the degree of freedom of the designed mechanism is 1, that is, when the input motion is determined, the mechanism has a unique output turning motion.

[0034] Place the mechanism in the rectangular coordinate system XOY. Each connecting rod in the mechanism can be expressed as a displacement vector. The magnitude of the displacement vector is the length of the connecting rod. The angle between the vector and the positive direction of the x-axis is the angle of the connecting rod (counterclockwise is positive), such as Figure 4 .

[0035] List the vector equations in the closed form OHBCGO, CBADC and EDGFE, project them on the x-axis and y-axis, and obtain the motion position equation of the mechanism;

[0036]

[0037] Through position analysis, we can examine whether the component can achieve the predetermined position and trajectory requirements. Formula (3) is a nonlinear transcendental equation about trigonometric functions. The Newton-Simpson iteration method is used to solve it and obtain the relationship curve between the angle change value of the movable vertical rod and the drive input value S. Formula (3) is rearranged to obtain the simultaneous equation system:

[0038] f i (θ)=0,i=1,...,6,θ=(θ2,θ3,θ4,θ5,θ6,θ7) (4)

[0039] Find the Jacobian matrix of the equation

[0040]

[0041] According to equations (4) and (5), given the initial reference value, the driving input value S is used as a parameter to obtain the relationship curve between S and the end rib angle change value θ4.

[0042] Given the length of each connecting rod and the position of the G and F coordinate points, such as l HB =200,l CB = l EF =23.5,l CD = l ED =22,l GD = l AD =38,l AB = l GF =30; G(x G ,y G )=(160.47,57.41); F(x F ,y F )=(160.47,27.41); the relationship between S and the end rib angle change value θ4 can be obtained as follows Figure 5 It can be seen that the maximum 37° turning angle can be achieved during the stable motion stage of the mechanism.

[0043] The above is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above specific structure, but also includes any structure that is equivalent or similar to the above technical features, as long as they can achieve the same or similar functions and achieve basically the same effect. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A wingtip folding mechanism for a morphing aircraft, characterized in that: The wing tip folding mechanism for a morphing aircraft comprises a driving unit (1), a driving rod (2), a vertical rod (3), an oblique short rod (4) and an oblique long rod (5); the vertical rods (3) are arranged in a single group or multiple groups, and comprise fixed vertical rods and movable vertical rods; the fixed vertical rods are installed on the fixed wing or the large wing side, and the movable vertical rods are installed on the small wing side to drive the outer wing to fold; the driving unit (1) is connected to one end of the driving rod (2), and the other end of the driving rod (2) is connected to the movable vertical rod to drive the movable vertical rod to move and drive the outer wing to fold; the fixed vertical rod and the movable vertical rod of the same group are connected to the oblique long rod (5) through the oblique short rod (4).

2. The wingtip folding mechanism for a morphing aircraft according to claim 1, characterized in that: The oblique short rod (4) and the oblique long rod (5) are inside the fixed vertical rod and the movable vertical rod; one end of the oblique short rod (4) is connected to the lower end of the vertical rod (3) of the same group, one end of the oblique long rod (5) is connected to the upper end of the vertical rod (3) of the same group, and the other end of the oblique short rod (4) is connected to the other end of the oblique long rod (5).

3. The wing tip folding mechanism for a morphing aircraft according to claim 2, characterized in that: Two oblique long rods (5) connecting the same group of vertical rods (3) intersect at an intersection.

4. The wing tip folding mechanism for a morphing aircraft according to claim 2, characterized in that: The oblique short rod (4) connected to the fixed vertical rod is connected to the oblique long rod (5) connected to the movable vertical rod; the oblique long rod (5) connected to the fixed vertical rod is connected to the oblique short rod (4) connected to the movable vertical rod.

5. The wingtip folding mechanism for a morphing aircraft according to claim 1, characterized in that: The wing tip folding mechanism for a morphing aircraft is a connecting rod mechanism, wherein the rods are connected by pins; when the driving unit (1) moves horizontally, the fixed vertical rod remains stationary, and the movable vertical rod is driven to fold upwards by the driving rod (2); during the folding process, the fixed vertical rod and the movable vertical rod are in a non-parallel state, and there is always an intersection point located outside the mechanism, which is the rotation center of the movable wing side.

6. The wingtip folding mechanism for a morphing aircraft according to claim 1, characterized in that: The wing tip folding mechanism for a morphing aircraft is connected to different groups of vertical rods (3) via a rigid shaft (6) to arrange multiple groups of mechanisms in a linear array.

7. The wing tip folding mechanism for a morphing aircraft according to claim 6, characterized in that: The multiple groups of mechanism linear arrays are arranged as follows: the driving rod (2) is connected to the middle of the rigid shaft (6), and the movable vertical rods in different groups of vertical rods (3) are connected to the rigid shaft (6) and are evenly distributed on both sides of the driving rod (2).

8. The wingtip folding mechanism for a morphing aircraft according to claim 1, characterized in that: The number of degrees of freedom of the wingtip folding mechanism for the morphing aircraft is 1. When the input motion is determined, the wingtip folding mechanism for the morphing aircraft has a uniquely determined output folding motion.

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