Deformable rib and method of use thereof

Abstract

The invention provides a deformation wing rib and a using method thereof. The deformation wing rib comprises a first rib plate and a second rib plate, and a rigid skin is arranged on the outer side face of the first rib plate of an actuating switch; the back face of the first middle rib plate and the front face of the first rib plate, the front face of the last middle rib plate and the back face of the second rib plate, and the adjacent middle rib plates are connected through multi-stable-state self-locking rotating joints; all the middle rib plates share a flexible skin, one end of the actuating switch flexible skin is connected with the second rib plate, and the other end of the actuating switch flexible skin extends to the first rib plate from a gap formed by the first rib plate and the first middle rib plate and is connected with a skin driver. According to the invention, the multi-degree-of-freedom change of the wing rib form is realized.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace technology, and particularly relates to a deformable wing rib and a method for using the same. Background Art

[0002] The design form of the wing has a crucial impact on aspects such as the aerodynamic performance, fuel efficiency, and noise characteristics of the aircraft. Due to strict limitations in multiple aspects such as material strength, design space, weight, and reliability, traditional wings usually adopt a fixed structural form as a compromise among various performance indicators and rely on flaps and ailerons to adjust their aerodynamic performance. However, this fixed structure is difficult to achieve continuous changes in the overall wing form, and has a single motion mode, which is only suitable for relatively specific flight missions and is difficult to cope with complex and changing flight environments and mission requirements.

[0003] With the development of social economy and the progress of aerospace technology, the requirements for the performance of aircraft are also constantly increasing, especially in terms of fuel economy, maneuverability, and adaptability to complex environments and missions. The traditional fixed-wing structure can no longer meet the development needs of the new generation of high-performance and multi-functional aircraft. Therefore, in recent years, experts and scholars have proposed various deformable wing design schemes, such as variable wingtips, variable wingspans, variable airfoils, variable sweepbacks, variable thicknesses, etc. Among them, the research on realizing wing deformation by changing the rib form has received particular attention because it can not only directly change the airfoil of the wing, but also achieve wing torsion through multiple non-synchronous moving ribs, thus better adapting to the needs of high-speed and low-speed missions and rapid maneuvers.

[0004] However, the current wings based on rib deformation design face some challenges: especially the multi-degree-of-freedom requirements for rib deformation lead to the complication of the deformable wing drive and control system, which in turn affects the robustness of the overall system and increases the weight and cost, making its engineering application face great difficulties.

[0005] Therefore, the existing deformable wing rib design schemes mainly focus on single degrees of freedom. For example, the variable leading-edge camber wing proposed by the Chinese Aeronautical Establishment (Patent No.: CN202311575372.2), the single-degree-of-freedom variable trailing-edge wing designed based on the fusion of the Watt six-bar mechanism and the Stephen six-bar mechanism (Patent No.: CN202211581668), and the single-degree-of-freedom variable trailing-edge rib designed by the Chinese Aircraft Strength Research Institute and Northwestern Polytechnical University (Literature DOI: 10.1051 / inwpu / 20234150942) based on a multi-joint rotation mechanism and a motion coupling link.

[0006] In addition, although the design based on a flexible structure can achieve continuous multi-degree-of-freedom deformation of the rib, there is a difficult-to-reconcile contradictory relationship between the stiffness (or load-bearing performance) of the flexible structure itself and the deformation range (such as the design solutions in CN202210410689 and CN201910680545), which limits the practical application of such designs. To improve the stiffness of such designs, it is often necessary to further utilize a rigid structural support, but this support will reduce the flexibility of rib deformation. For example, the deformable rib designed by Nanjing University of Aeronautics and Astronautics based on a flexible structure and a rigid straight beam support (CN202211070045) can only achieve the deformation movement in the chord direction of the wing.

[0007] In summary, it is still a challenging task to achieve multi-degree-of-freedom changes in the rib shape with a simple mechanism / structure and drive-control system. Summary of the Invention

[0008] The purpose of the present invention is to provide a deformable rib and its usage method, which can achieve multi-degree-of-freedom changes in the rib shape with a simple mechanism / structure and drive-control system. The technical solution adopted is as follows:

[0009] A deformable rib, comprising:

[0010] A first rib plate 1 and a second rib plate 2, with a rigid skin provided on the outer side surface of the first rib plate 1;

[0011] At least one intermediate rib plate 3, which is connected by multi-stable self-locking rotating joints between the back surface of the first intermediate rib plate and the front surface of the first rib plate 1, between the front surface of the last intermediate rib plate and the back surface of the second rib plate 2, and between adjacent intermediate rib plates;

[0012] All intermediate rib plates share a flexible skin 4-1, one end of the flexible skin 4-1 is connected to the second rib plate 2, and the other end of the flexible skin 4-1 extends from the gap formed by the first rib plate 1 and the first intermediate rib plate to the first rib plate 1 and is connected to a skin driver 4-2; the skin driver 4-2 is arranged on the back surface or the front surface of the first rib plate 1.

[0013] Preferably, the multi-stable self-locking rotating joint between the first rib plate 1 and the first intermediate rib plate includes: a cam mechanism and a self-locking component;

[0014] The cam mechanism is used to drive the tip 2-1 of the energy storage self-guiding part 1-2 to perform reciprocating motion in the radial direction, and it includes:

[0015] An inner cam ring 1-1, which is arranged on the back surface of the first intermediate rib plate and can rotate with the first intermediate rib plate, and its back surface is open and concave to form an inner edge including a plurality of wave peaks and wave valleys;

[0016] The energy storage self-guiding member 1-2 is located within the area surrounded by the inner edge and is rotatably arranged on the front surface of the first rib plate 1 through a rotating cylinder. One end of the tip 2-1 radially passes through the rigid constraint groove 2-3 and contacts the inner edge of the inner cam ring 1-1. The rigid constraint groove 2-3 is formed in the rigid arc beam. The tip 2-1 is arranged on the outer edge of the flexible arc beam 2-2, and the flexible arc beam 2-2, the rigid arc beam are connected to the rotating cylinder.

[0017] The self-locking component is used to unlock or lock the inner cam ring 1-1, and includes a driving unit arranged on the first rib plate 1 and a hook 3-1 connected to the output end of the driving unit.

[0018] The front surface of the hook 3-1 fits against the back surface of the inner cam ring 1-1, its end extends to the area surrounded by the flexible arc beam 2-2, and its back surface fits against the first rib plate 1. The end of the hook 3-1 fits against the inner edge of the flexible arc beam 2-2.

[0019] Preferably, a first shaft hole is formed on the front surface of the inner cam ring 1-1, a second shaft hole is formed on the rotating cylinder, and the first shaft hole communicates with the second shaft hole.

[0020] The first shaft hole is in interference fit or key connection with a first rotating shaft on the back surface of the first intermediate rib plate so that the inner cam ring 1-1 can rotate with the first intermediate rib plate.

[0021] The second shaft hole is in interference fit or key connection with a second rotating shaft on the front surface of the first rib plate 1.

[0022] Preferably, the front surface of the hook 3-1 fits against the back surface of the rigid arc beam and the back surface of the flexible arc beam 2-2.

[0023] Preferably, for the multi-stable self-locking rotating joint between adjacent intermediate rib plates, its energy storage self-guiding member and self-locking component are arranged on the front surface of an intermediate rib plate close to the first rib plate 1, and its inner cam ring is arranged on the back surface of an intermediate rib plate close to the second rib plate 2.

[0024] Preferably, the driving unit of the self-locking component includes:

[0025] A five-bar mechanism, which includes a first rod 3-2, a second rod 3-3, a third rod 3-4, and a fourth rod 3-5 that are sequentially hinged. The second rod 3-3 and the third rod 3-4 are hinged through a vertex hinge column 3-12. The vertex hinge column 3-12 cooperates with a switch groove formed on the front surface of the first rib plate 1.

[0026] Both the first rod 3-2 and the fourth rod 3-5 are used to clamp the hook 3-1 and are respectively connected to the first rib plate 1 through a fixed hinge, a first fixed hinge support 3-8, and a second fixed hinge support 3-9.

[0027] The actuating switch 3-7 is arranged on the first rib plate 1 and connected to the vertex hinge column 3-12, and its output end can generate a linear displacement and coincide with the center line of the switch groove;

[0028] The elastic element 3-13 is arranged on the front surface of the first rib plate 1 and close to the cam mechanism;

[0029] In the self-locking state, the elastic element 3-13 is in a pre-compressed or natural state.

[0030] Preferably, a chute is formed on the flexible skin 4-1, and a fastener for positioning the flexible skin 4-1 on the middle rib plate 3 is arranged in the chute. The rod body of the fastener is connected to the corresponding middle rib plate 3, and its cap body contacts the flexible skin 4-1.

[0031] Preferably, the first rib plate 1 forms the large end of the deformable wing rib, and the second rib plate 2 forms the small end of the deformable wing rib.

[0032] A method for using a deformable wing rib includes the following steps:

[0033] Releasing the corresponding multi-stable self-locking rotating joint under the action of the actuating switch 3-7;

[0034] Then pushing or pulling the flexible skin 4-1 through the skin driver to rotate the multi-stable self-locking rotating joint;

[0035] When the multi-stable self-locking rotating joint runs to the required stable position, close the actuating switch 3-7.

[0036] Compared with the prior art, the advantages of the present invention are:

[0037] 1. Achieving multi-degree-of-freedom and stable motion with a simple structural design: The multi-stable joint designed based on the multi-stable cam and the rigid-flexible coupling energy storage-guidance integrated part is very convenient for multi-scale manufacturing and assembly, making this design easy to be arranged in a thinner wing. Through the combination of multiple joints, rich stable forms and a large deformation scale can also be achieved.

[0038] 2. The multi-stable deformable wing rib has strong load-bearing capacity and can achieve low-energy self-conformal: By introducing a hook self-locking component, the wing rib can be locked in a non-energy-consuming state under normal conditions. And since the hook is in a tension state, theoretically its failure depends on the tensile strength of the material, and the stiffness mainly depends on the tensile stiffness of the hook structure. Therefore, it can have excellent locking load-bearing capacity and locking stiffness.

[0039] 3. Simple drive and control system: The multi-stable motion characteristics enable the multi-stable deformable wing rib to achieve precise regulation of the steady-state pose without the aid of sensors. In addition, in cooperation with the internal unlocking actuation switch, underactuated regulation of the overall wing rib degrees of freedom can be achieved, that is, through the upper and lower skin drivers, multi-degree-of-freedom regulation of the overall wing rib can be realized. Description of the Drawings

[0040] Figure 1 is a perspective view of the deformable wing rib;

[0041] Figure 2 is a plan view of the multi-stable self-locking rotating joint;

[0042] Figure 3 is a sectional view taken along the line A-A;

[0043] Figure 4 is a perspective view of the multi-stable self-locking rotating joint;

[0044] Figure 5 is a schematic diagram of the moving direction of the hook during the process of switching from the self-locking state to the unlocking state;

[0045] Figure 6 is a plan view of the energy storage self-guiding part;

[0046] Figure 7 is a plan view of the inner cam ring;

[0047] Figure 8 is a schematic diagram of the installation position of the skin system;

[0048] Figure 9 is a schematic diagram of the position of the multi-stable self-locking rotating joint between the last intermediate rib plate and the second rib plate;

[0049] Figure 10 is a state diagram of the deformed wing rib after deformation;

[0050] Figure 11 is a connection schematic diagram of the first rib plate, the second rib plate, the intermediate rib plates and all multi-stable self-locking rotating joints;

[0051] Figure 12 is a diagram of the positional relationship between the first intermediate rib plate and the flexible skin;

[0052] Figure 13 is a perspective view of the first rib plate;

[0053] Figure 14 is a perspective view of the second rib plate;

[0054] Figure 15 is a connection schematic diagram of the first intermediate rib plate and the first rib plate;

[0055] Figure 16 Schematic diagram of the connection between the last intermediate rib and the second rib

[0056] Figure 17 Position relationship diagram between the first intermediate rib and the multi-stable self-locking rotating joint

[0057] Figure 18 Relative position relationship diagram between the first rib and the first intermediate rib

[0058] Figure 19 Relative position relationship diagram between the second rib and the last intermediate rib

[0059] Figure 20 Schematic diagram of the installation position of the flexible skin

[0060] Figure 21 Position relationship diagram between the chute, fastener and flexible skin

[0061] Figure 22 Position relationship diagram between the hook and the limit slot in the self-locking state

[0062] Figure 23 Schematic diagram of the positions of the first shaft hole and the second shaft hole

[0063] Figure 24 Schematic diagram of section B at the end of the flexible skin

[0064] Among them, 1 - the first rib, 2 - the second rib, 3 - the intermediate rib;

[0065] 1-1, inner cam ring,

[0066] 1-2, energy storage self-guiding part, 2-1, tip, 2-2, flexible arc beam, 2-3, rigid constraint groove,

[0067] 3-1, hook, 3-2, first rod, 3-3, second rod, 3-4, third rod, 3-5, fourth rod, 3-6, fixed hinge support, 3-7, actuation switch, 3-8, first fixed hinge support, 3-9, second fixed hinge support, 3-10, locking groove, 3-11, boss, 3-12, vertex hinge column; 3-13 - elastic element;

[0068] 4-1, flexible skin, 4-2 skin driver, 4-3, connecting piece. Specific implementation method

[0069] The variable wing rib of the present invention and its usage method will be described in more detail below in conjunction with schematic diagrams, in which the preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as broad knowledge for those skilled in the art and not as a limitation to the present invention.

[0070] As Figures 1 to 23 , a variable wing rib, which is a variable wing rib with large load, high stiffness, underactuated, and multi-stable states, includes: multiple movable rib plates I, multi-stable self-locking rotating joints II and flexible skin drive systems III installed thereon. Specifically:

[0071] The first rib plate 1 and the second rib plate 2, with a rigid skin provided on the outer side of the first rib plate 1; the first rib plate 1 forms the large end of the variable wing rib, and the second rib plate 2 forms the small end of the variable wing rib. As Figures 12 to 14 shown, it is the specific structure of the rib plate.

[0072] At least one intermediate rib plate 3, which is connected by multi-stable self-locking rotating joints between the back of the first intermediate rib plate and the front of the first rib plate 1, between the front of the last intermediate rib plate and the back of the second rib plate 2, and between adjacent intermediate rib plates;

[0073] All intermediate rib plates share a flexible skin 4-1, and one end of the flexible skin 4-1 is connected to the second rib plate 2.

[0074] As Figure 12 , Figure 20 shown, the other end of the flexible skin 4-1 extends from the gap formed by the first rib plate 1 and the first intermediate rib plate to the inner side of the first rib plate 1 or the inner side of the rigid skin, and is connected to the skin driver 4-2.

[0075] Specifically, if the flexible skin 4-1 extends to the inner side of the first rib plate 1, the skin driver 4-2 is arranged on the back of the first rib plate 1.

[0076] If the flexible skin 4-1 extends to the inner side of the rigid skin, the skin driver 4-2 is arranged on the front of the first rib plate 1.

[0077] In this embodiment, the flexible skin 4-1 extends to the inner side of the first rib plate 1.

[0078] There are slits on the rib plate or the flexible skin, so that the end section of the flexible skin 4-1 will not interfere with the first rib plate 1 and can slide along the first rib plate 1, and the end section of the flexible skin 4-1 extends to the inner side of the skin driver 4-2.

[0079] In this embodiment, as Figure 1As shown, the end section of the flexible skin 4-1 is flush with other sections of the flexible skin 4-1. The end section of the flexible skin 4-1 includes section A and section B, and a gap is formed between section A and section B. That is, for the end section of the flexible skin 4-1, section A extends to the front of the first rib plate 1 (as Figure 1 shown), and section B extends to the back of the first rib plate 1 (as Figure 12 shown).

[0080] As Figure 12 shown, the skin driver is arranged on the back of the first rib plate 1, and the gap is such that section A extends to the front of the first rib plate 1 and section B extends to the back of the first rib plate 1.

[0081] Figure 12 、 Figure 24 In , section A at the end of the flexible skin 4-1 is not shown, and only section B is displayed.

[0082] In this embodiment, as Figure 11 shown, it includes 2 intermediate rib plates, so there are 3 rotating joints. In other embodiments, the number of intermediate rib plates can be 1 or more than 2.

[0083] Among them, the end of the first rib plate 1 (the end away from the second rib plate 2) is fixed to the leading edge of the wing and is a fixed rib plate. The second rib plate 2 and the intermediate rib plates 3 can all rotate under the action of the flexible skin 4-1.

[0084] The structures of all multi-stable self-locking rotating joints are the same. The difference lies in the installation positions of the multi-stable self-locking rotating joints. In this embodiment, taking the multi-stable self-locking rotating joint between the first rib plate 1 and the first intermediate rib plate as an example, the structure is described as follows:

[0085] The multi-stable self-locking rotating joint between the first rib plate 1 and the first intermediate rib plate includes: a cam mechanism and a self-locking component.

[0086] The cam mechanism is used to drive the tip 2-1 of the energy storage self-guiding part 1-2 to reciprocate radially. It includes: an inner cam ring 1-1 and an energy storage self-guiding part 1-2, which are respectively installed on two rotatable rib plates. Adjacent rib plates have the same rotation center, forming a passive joint that can rotate in multiple stable states.

[0087] The inner cam ring 1-1 is arranged on the back of the first intermediate rib plate and can rotate with the first intermediate rib plate. Its back is open and concave to form an inner edge including a plurality of wave crests and wave troughs, as Figure 7 shown.

[0088] Specifically: for the inner cam ring 1-1, the working curve (inner edge) is enveloped between the cam base circle and the maximum outer envelope circle, and this curve has multiple up and down fluctuations, forming multiple wave crests and wave troughs. The bottom of the wave trough is tangent to the base circle.

[0089] The energy storage self-guiding part 1-2 is located within the area surrounded by the inner edge and is rotatably arranged on the front surface of the first rib plate 1 through a rotating cylinder. Among them, the energy storage self-guiding part 1-2 is a rigid-flexible coupling energy storage and self-guiding part.

[0090] One end of the tip 2-1 passes through the rigid constraint groove 2-3 along the radial direction and contacts the inner edge of the inner cam ring 1-1. The rigid constraint groove 2-3 is formed on the rigid arc beam; as Figure 4 , Figure 6 and Figure 15 shown. A small gap should be reserved between the rigid guiding groove 2-3 and the tip to reduce friction and increase the service life of the part.

[0091] The tip 2-1 is arranged on the outer edge of the flexible arc beam 2-2. Both the flexible arc beam 2-2 and the rigid arc beam are connected to the rotating cylinder. The compressible range of the flexible arc beam should be less than the length of the tip.

[0092] As Figure 6 shown, the energy storage self-guiding part 1-2 is a single part, integrally processed. The thickness of the rigid arc beam is greater than the thickness of the flexible arc beam 2-2. The tip 2-1 and the flexible arc beam 2-2 are integrally formed.

[0093] That is, for the energy storage self-guiding part 1-2, the tip 2-1 in contact with the inner edge contour of the cam is connected with the flexible arc beam 2-2. There is a rigid constraint groove 2-3 formed by the rigid arc beam on the side of the tip 2-1. The above-mentioned rigid / flexible beams are fixedly connected on the other side not in contact with the tip, forming a single part that can be integrally processed.

[0094] Regarding the cooperation process of the first rib plate 1 and the first intermediate rib plate, the inner cam ring 1-1 and the energy storage self-guiding part 1-2:

[0095] In the unlocked state, when the first intermediate rib plate rotates, the tip 2-1 will always be in contact with the inner edge of the cam under the elastic force of the flexible arc beam 2-2, forming an elastic force-closed cam mechanism. And, under the action of the sliding guiding constraint groove (rigid constraint groove 2-3), the tip 2-1 always moves along the radial direction of the rotation center.

[0096] When the tip contacts the trough, it is the steady-state position of the rotating joint.

[0097] Due to the existence of multiple peaks and troughs on the cam contour, this joint can have multiple steady-state positions.

[0098] In addition, after unlocking, regarding the rotational movement:

[0099] For the first rib plate 1 and the first intermediate rib plate: During the rotation of the inner cam ring 1-1 under the action of an external force, since the first rib plate 1 is a fixed rib plate, the tip 2-1 thereon will not rotate. Under the constraint of the rigid arc beam guide groove, there is only radial movement.

[0100] For other inner cam rings 1-1 and tips 2-1, they will all rotate under the action of an external force.

[0101] Among them, the external force is applied by the skin driver 4-2 through the flexible skin 4-1.

[0102] After unlocking the first joint, for example, the flexible skin 4-1 applies an external force, and the tip 2-1 on the first rib plate 1 will not rotate, while the remaining tips 2-1 and the inner cam rings will rotate synchronously with the first intermediate rib plate.

[0103] The self-locking component is used to unlock or lock the inner cam ring 1-1, and it includes a driving unit arranged on the first rib plate 1 and a hook 3-1 connected to the output end of the driving unit;

[0104] The hook 3-1 has its front surface fitting the back surface of the inner cam ring 1-1, its end extending to the area surrounded by the flexible arc beam 2-2, and its back surface fitting the first rib plate 1; in the self-locking state, the end of the hook 3-1 fits the inner edge of the flexible arc beam 2-2.

[0105] To ensure that the inner cam ring 1-1 and the energy storage self-guiding part 1-2 are respectively connected to different rib plates and have the same rotation center, the following design is made:

[0106] Such as Figure 3 、 Figure 18 As shown, a first shaft hole is opened on the front surface of the inner cam ring 1-1, a second shaft hole is opened on the rotating cylinder, the first shaft hole communicates with the second shaft hole, and both are through holes, as Figure 23 shown.

[0107] The first shaft hole is in interference fit or key connection with the first rotating shaft on the back surface of the first intermediate rib plate so that the inner cam ring 1-1 can rotate with the first intermediate rib plate. That is, the inner cam ring 1-1 is positioned on the first intermediate rib plate by connecting with the first rotating shaft on the back surface of the first intermediate rib plate.

[0108] Such as Figure 15 、 Figure 17 As shown, the front surface of the inner cam ring 1-1 fits the back surface of the first intermediate rib plate, the first rotating shaft is fixed to the back surface of the first intermediate rib plate and cooperates with the first shaft hole.

[0109] The second shaft hole is in interference fit or key connection with the second rotating shaft on the front surface of the first rib plate 1. That is, the energy storage self-guiding part 1-2 is positioned on the first rib plate 1 through the rotating cylinder therein.

[0110] Thus, the inner cam ring 1-1 and the energy storage self-guiding member 1-2 are respectively connected to different rib plates.

[0111] As Figure 15 , Figure 18 shown, the second rotating shaft is fixed to the front surface of the first rib plate 1 and is in fit with the second shaft hole.

[0112] Among them, the first rotating shaft and the second rotating shaft do not contact each other.

[0113] Furthermore, the front surface of the hook 3-1 fits against the back surface of the rigid arc beam and the back surface of the flexible arc beam 2-2.

[0114] That is, the back surfaces of the rigid arc beam and the flexible arc beam 2-2 are flush with the back surface of the inner cam ring, and gaps are formed between the three of them and the front surface of the first rib plate 1. That is, the three of them are in a suspended state relative to the first rib plate 1.

[0115] Furthermore, as Figure 13 shown, a limiting groove is formed on the front surface of the first rib plate 1 and is in fit with the hook 3-1.

[0116] In the unlocked state, the hook moves radially inward along the limiting groove towards the center of the inner cam ring 1-1;

[0117] In the self-locking state, the hook 3-1 contacts the left end of the limiting groove, as Figure 22 shown.

[0118] As Figures 2 to 5 : One side of the hook body of the hook hooks the bottom of the tip 2-1 (that is, the area where the outer side of the flexible arc beam is connected to the tip), and the other side is a vertical beam perpendicular to the hook body. There are bosses 3-11 at both ends of the beam, and the bosses 3-11 can be snapped into the locking groove 3-10 on the five-bar mechanism.

[0119] As Figures 2 to 5 shown, the drive unit includes: a five-bar mechanism, an actuation switch 3-7, and an elastic element 3-13.

[0120] The five-bar mechanism includes a first rod 3-2, a second rod 3-3, a third rod 3-4, and a fourth rod 3-5 that are sequentially hinged; the second rod 3-3 and the third rod 3-4 are hinged through a vertex hinge column 3-12; the vertex hinge column 3-12 is in fit with the switch groove formed on the front surface of the first rib plate 1; the structure of the switch groove is as Figure 13 shown.

[0121] Both the first rod 3-2 and the fourth rod 3-5 are used to clamp the hook 3-1 and are respectively connected to the first rib plate 1 through a fixed hinge, a first fixed hinge support 3-8 and a second fixed hinge support 3-9. The first fixed hinge support 3-8 and the second fixed hinge support 3-9 form the frame of the five-bar mechanism;

[0122] Actuating switch 3-7 is arranged at the hinge joint between the first rib plate 1 and the vertex hinge column 3-12, and its output end generates a linear displacement and coincides with the center line of the switch groove.

[0123] Among them, the actuating switch 3-7 is a linear actuator, one end of which is fixed to the fixed hinge support 3-6, and the other end is sleeved on the vertex hinge column 3-12, as Figure 13 shown.

[0124] Specifically, the actuating switch 3-7 selects electromagnetic, hydraulic, pneumatic actuators or actuators based on smart materials with small size and light weight. In this embodiment, a self-resetting two-way shape memory alloy (SMA) spring is used;

[0125] Among them, the two-way SMA spring can contract after being energized / heated to generate a driving displacement. In this embodiment, the two-way SMA is directly connected to the DC power supply on the aircraft, and it can generate heat and contract after being energized, and can recover its initial length automatically after being powered off.

[0126] Elastic element 3-13 is arranged on the front surface of the first rib plate 1 and close to the cam mechanism;

[0127] In the self-locking state, the directions of the first rod 3-2 and the fourth rod 3-5 are parallel to the symmetry line of the hook. At this time, the upper and lower ends on the left side of the hook are clamped in the locking groove 3-10 on the rod by the first rod and the fourth rod, and are in close contact with the locking groove 3-10. The hook 3-1 hooks the area where the inner side of the flexible arc beam 2-1 is connected to the tip. At this time, the tip 2-1 contacts the trough of the cam profile. In the self-locking state, the elastic element 3-13 is in a pre-compressed or natural state.

[0128] Natural state, that is, at this time the ductile element 3-13 is at its original length.

[0129] When unlocking, as Figure 5 shown, under the driving action of the SMA contraction, after the first rod 3-2 and the fourth rod 3-5 are separated from the hook 3-1, the movement of the tip and the hook along the radial direction of the cam is no longer restricted. The outer ring cam 1-1 can rotate under the action of an external force and drive the whole composed of the tip 2-1 and the hook 3-1 to move along the radial direction of the outer ring cam 1-1.

[0130] That is, as Figure 5 shown, after unlocking one of the multi-stable self-locking rotating joints, when the inner ring cam 1-1 rotates relative to the energy storage self-guiding member 1-2, it drives the tip 2-1 at the stable position to move radially to separate from the trough. During the process of the tip 2-1 separating from the trough and abutting against the next trough, the flexible arc beam 2-1 always drives the hook 3-1 to move (the moving direction is as Figure 5 shown, first move in the direction of the solid arrow, and then move in the direction of the dotted arrow).

[0131] As can be seen from the above, the rotation of the inner ring cam 1-1 relative to the energy storage self-guiding member 1-2 means that:

[0132] Only one multi-stable self-locking rotating joint is unlocked each time.

[0133] For example, unlock the second joint (the multi-stable self-locking rotating joint between the first intermediate rib and the second intermediate rib).

[0134] Apply an external force, and the inner ring cam 1-1 on the second intermediate rib rotates. However, the first rib 1 and the first intermediate rib cannot rotate under the locking action of the first joint (self-locking state). The second rib 2 rotates with the second intermediate rib under the locking action of the third joint (self-locking state).

[0135] Therefore, the inner ring cam 1-1 on the second intermediate rib rotates, while the corresponding energy storage self-guiding member 1-2 does not rotate.

[0136] Thus, the inner ring cam 1-1 rotates relative to the energy storage self-guiding member 1-2.

[0137] During the process of transitioning from the unlocked state to the next self-locking state, the inner ring cam first drives the tip and the hook to move radially, that is, the hook 3-1 moves along Figure 5 the direction of the solid arrow shown. During this movement, the elastic element 3-13 and the flexible arc beam 2-2 will be compressed.

[0138] Among them, the pulling force of the elastic element 3-13 on the hook 3-1 is small, so that under the combined action of the flexible arc beam 2-2 and the elastic element 3-13, the hook 3-1 can move along Figure 5 the direction of the solid arrow shown.

[0139] In the unlocked or self-locking state, the hook 3-1 always hooks the bottom of the tip 2-1.

[0140] The state (compressed state or natural state) of the elastic element 3-13 at the steady state position is the initial state. During the process of transitioning from the steady state position to the next steady state position, the elastic element 3-13 is always in a compressed state. Under the thrust of the elastic element 3-13 in the direction of the dashed arrow, the hook 3-1 automatically moves to the left (towards the direction of the five-bar mechanism), and the clamping rod contracts. The combination of these two movements causes the hook to automatically snap into the locking groove 3-10 when the tip moves to the trough.

[0141] That is, when reaching the next trough (steady state position), the elastic element 3-13 resets to the initial state, and the five-bar mechanism relocks the hook 3-1.

[0142] In the self-locking state, the actuating switch 3-7 does not displace, and the five-bar mechanism is pressed against the hook by the stiffness (elastic force) of the elastic element itself.

[0143] In summary, the five-bar mechanism is fixed to the same rib plate (or movable rib plate) as the energy storage self-guiding part 1-2 through two hinges. The frame of the five-bar mechanism is formed between the two fixed hinges (the first fixed hinge support 3-8 and the second fixed hinge support 3-9). The frame and the other four movable rods are all symmetrical about the symmetry axis of the hook, and the symmetry axis of the hook points to the center of joint rotation.

[0144] The four movable rods include two driving rods (the second rod 3-3 and the third rod 3-4), and two clamping follower rods (the first rod 3-2 and the fourth rod 3-5). Under the action of the actuating switch 3-7, the driving rods can perform circular motion along the hinges. The follower members are fixed to the movable rib plate through fixed hinges and perform expansion and contraction motions along the symmetry plane of the mechanism.

[0145] Working principle of the driving unit:

[0146] The joint is normally locked, and the actuating switch does not provide any driving displacement. Under the action of the actuating switch 3-7, the hook will automatically snap into the locking groove of the clamping follower rod. At this time, the follower rod is in the horizontal position, and even if it bears the axial load transmitted by the hook, it will not cause the follower rod to rotate, that is, the movement of the hook is completely blocked by the five-bar mechanism.

[0147] At this locked position, the tip 2-1 of the energy storage self-guiding part 1-2 contacts the trough of the inner edge contour of the cam. The hook will hook the bottom of the tip, restricting its movement away from the trough, and further preventing the cam mechanism from moving, realizing the locking of the multi-stable joint at the stable position.

[0148] If the joint is to be released, the actuating switch will generate a contraction displacement, which will in turn drive the clamping follower rod of the five-bar mechanism to perform an outward expansion movement, causing the boss 3-11 on the left vertical beam of the hook to disengage from the locking groove 3-10. At this time, the inner cam ring can rotate under the action of an external force and drive the tip to perform reciprocating motion along the rigid constraint groove 2-3, realizing the switching of the stable position. Specifically, the locking groove 3-10 is a recessed structure corresponding to the boss 3-11 on the vertical beam, and its size is slightly larger than the size of the boss, facilitating the movement of the left side of the hook into the locking groove 3-10.

[0149] Regarding the flexible skin drive system II, it includes a flexible skin 4-1, a skin driver 4-2, and a connecting piece 4-3.

[0150] All intermediate rib plates share a flexible skin 4-1, and one end of the flexible skin 4-1 is connected to the second rib plate 2.

[0151] Such as Figure 1 、 Figure 12 、Figure 20 As shown, the other end of the flexible skin 4-1 extends to the back of the first rib 1 through the gap formed by the first rib 1 and the first intermediate rib, and is connected to the skin actuator 4-2 provided on the back of the first rib 1 through the connector 4-3. The flexible skin 4-1 is provided with a slit and can slide on the first rib 1. The skin actuator 4-2 includes a platform that can move linearly.

[0152] As Figure 1 、 Figure 21 As shown, a chute is provided on the flexible skin 4-1, and rivets or screws for positioning the flexible skin 4-1 on the intermediate rib 3 are provided in the chute; for the rivet, its rod body is fixed to the corresponding intermediate rib 3, and its cap body contacts the flexible skin 4-1.

[0153] The chute can enable the flexible skin 4-1 to slide along the chord length direction of the wing on the surface of the rib.

[0154] The skin actuator 4-2 adopts a linear drive module, that is, a ball screw including a motor and a moving platform. The connector 4-3 is connected to the nut of the ball screw.

[0155] In summary, the skin actuator is a linear actuator, installed on the first rib 1 (fixed rib), and there is a platform on the actuator that can move linearly. The flexible skin covers the outside of the deformable rib and is fixedly connected to the second rib 2 after the last joint of the rib. It is fixedly connected to the moving platform on the skin actuator 4-2 through the connector 4-3.

[0156] To make the skin closely adhere to the side surface of the rib, rivets / or screws press it on the upper / lower surface of the rib. In addition, a rivet chute is provided on the skin surface, which can enable the skin to slide along the chord length direction of the wing on the surface of the rib.

[0157] When the rib needs to deform, under the action of the actuation switch 3-7, the first joint is released, and the two flexible skins 4-1 are pushed / pulled by the skin actuator. After adjusting the joint angle to the corresponding steady state position, the actuation switch is closed to realize the adjustment and self-locking of the steady state position of the joint.

[0158] More specifically, there is a kinematic relationship between the steady state position and the adjustment of the skin. By using this relationship, the position control of the skin actuator can be carried out.

[0159] When the joint moves near the required steady state, it will adaptively move to the locking position. As long as the tip points to the trough position of the steady state, it can achieve adaptive locking under the action of the self-locking spring.

[0160] Then, repeat this process successively to adjust the steady-state positions of each joint, so as to realize the shape adjustment of a deformable wing rib with n (n can be any positive integer) degrees of freedom by using the drivers on the upper and lower skins and combining with an unlocking actuation switch with simple functions. When n≥3, it is an underactuated shape adjustment design.

[0161] Regarding other multi-stable self-locking rotating joints:

[0162] For the multi-stable self-locking rotating joints between adjacent intermediate rib plates, its energy storage self-guiding part and self-locking part are arranged on the front of an intermediate rib plate close to rib plate 1, and its inner cam ring is arranged on the back of an intermediate rib plate close to rib plate 2.

[0163] For the multi-stable self-locking rotating joint between the last intermediate rib plate and rib plate 2, its energy storage self-guiding part and self-locking part are arranged on the front of the last intermediate rib plate, and its inner cam ring is arranged on the back of rib plate 2.

[0164] By connecting multiple joints with the same or different sizes in series with the movable rib plates, a deformable wing rib composed of multiple multi-stable joints can be formed ( Figure 1 ). If there are n troughs in the cam profile within the movement space of each joint, and there are m joints connected in series on the wing rib of the aircraft, then this deformable wing rib has m degrees of freedom and can form a total of m×n steady-state forms. Through the combination of multiple wing ribs, the overall wing can achieve various forms of downward bending, reverse warping, and torsion.

[0165] The movable rib plates should have the characteristics of simple drive system and light weight, which can effectively reduce the structural weight. At the same time, they have a high specific strength and can achieve good movable performance on the premise of ensuring strength.

[0166] The working principle of this deformable wing rib:

[0167] Each rib plate is connected by a multi-stable self-locking rotating joint, and a skin drive system is covered on the surface of the wing rib of the aircraft;

[0168] Such as Figure 1 , when maintaining the steady state:

[0169] The skins are kept stable. In the self-locking part, the five-bar mechanism locks the vertical beam, providing a binding force perpendicular to the symmetry axis of the component. At the same time, the hook hooks the bottom of the tip to ensure that the tip is in close contact with the trough of the cam ring, realizing non-energy-consuming locking in the normal state.

[0170] When the wing rib needs to be deformed:

[0171] Under the action of the actuation switch 3-7, a joint is released. The two flexible skins 4-1 are pushed / pulled by the skin driver. After adjusting the joint angle to the required steady-state position, the unlocking actuation switch is closed to realize the steady-state position adjustment and self-locking of this joint.

[0172] Then, repeat this process successively to adjust the steady-state position of each joint until the desired shape structure is achieved, as Figure 10 shown.

[0173] The above are only the preferred embodiments of the present invention and do not impose any limitation on the present invention. Any person skilled in the art, within the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification and other changes to the technical solutions and technical contents disclosed by the present invention, which are all within the content of the technical solution of the present invention and still fall within the protection scope of the present invention.

Claims

1. A variable wing rib, characterized in that, Comprising: A first rib plate (1) and a second rib plate (2), with a rigid skin provided on the outer side of the first rib plate (1); At least one intermediate rib plate (3), where between the back surface of the first intermediate rib plate and the front surface of the first rib plate (1), between the front surface of the last intermediate rib plate and the back surface of the second rib plate (2), and between adjacent intermediate rib plates, they are all connected by multi-stable self-locking rotating joints; All intermediate rib plates share a flexible skin (4-1), one end of the flexible skin (4-1) is connected to the second rib plate (2), and the other end of the flexible skin (4-1) extends from the gap formed by the first rib plate (1) and the first intermediate rib plate to the first rib plate (1) and is connected to the skin driver (4-2); the skin driver (4-2) is arranged on the back surface or the front surface of the first rib plate (1).

2. The variable wing rib according to claim 1, characterized in that, The multi-stable self-locking rotating joint between the first rib plate (1) and the first intermediate rib plate includes: a cam mechanism and a self-locking component; The cam mechanism is used to drive the tip (2-1) of the energy storage self-guiding member (1-2) to perform reciprocating motion in the radial direction, and it includes: An inner cam ring (1-1), which is arranged on the back surface of the first intermediate rib plate and can rotate with the first intermediate rib plate, its back surface is open and concave to form an inner edge including several wave crests and wave troughs; The energy storage self-guiding member (1-2), located within the area surrounded by the inner edge, is rotationally arranged on the front surface of the first rib plate (1) through a rotating cylinder, one end of the tip (2-1) passes through the rigid constraint groove (2-3) in the radial direction and contacts the inner edge of the inner cam ring (1-1), the rigid constraint groove (2-3) is opened on the rigid arc beam; the tip (2-1) is arranged on the outer edge of the flexible arc beam (2-2), and the flexible arc beam (2-2), the rigid arc beam are connected to the rotating cylinder; The self-locking component is used to unlock or lock the inner cam ring (1-1), and it includes a driving unit arranged on the first rib plate (1) and a hook (3-1) connected to the output end of the driving unit; The hook (3-1), its front surface fits against the back surface of the inner cam ring (1-1), its end extends to the area surrounded by the flexible arc beam (2-2), and its back surface fits against the first rib plate (1); the end of the hook (3-1) fits against the inner edge of the flexible arc beam (2-2).

3. The variable wing rib according to claim 2, characterized in that A first shaft hole is opened on the front surface of the inner cam ring (1-1), and a second shaft hole is opened on the rotating cylinder, and the first shaft hole communicates with the second shaft hole; The first shaft hole is in interference fit or key connection with the first rotating shaft on the back surface of the first intermediate rib plate so that the inner cam ring (1-1) can rotate with the first intermediate rib plate; The second shaft hole is in interference fit or key connection with the second rotating shaft on the front surface of the first rib plate (1).

4. The variable wing rib according to claim 2, characterized in that The front surface of the hook (3-1) fits against the back surface of the rigid arc beam and the back surface of the flexible arc beam (2-2).

5. The variable wing rib according to claim 2, characterized in that For the multi-stable self-locking rotating joint between adjacent intermediate rib plates, its energy storage self-guiding member and self-locking component are arranged on the front surface of an intermediate rib plate close to the first rib plate (1), and its inner cam ring is arranged on the back surface of an intermediate rib plate close to the second rib plate (2).

6. The variable wing rib according to claim 2, characterized in that, The driving unit of the self-locking component includes: A five-bar mechanism, which includes a first rod (3-2), a second rod (3-3), a third rod (3-4), and a fourth rod (3-5) that are sequentially hinged; the second rod (3-3) and the third rod (3-4) are hinged through a vertex hinge column (3-12); the vertex hinge column (3-12) cooperates with a switch groove opened on the front surface of the first rib plate (1). Both the first rod (3-2) and the fourth rod (3-5) are used to clamp the hook (3-1), and are respectively connected to the first rib plate (1) through a fixed hinge, a first fixed hinge support (3-8), and a second fixed hinge support (3-9). An actuating switch (3-7) is arranged on the first rib plate (1) and connected to the vertex hinge column (3-12), and its output end can generate a linear displacement and coincide with the center line of the switch groove. An elastic element (3-13) is arranged on the front surface of the first rib plate (1) and is arranged close to the cam mechanism. In the self-locking state, the elastic element (3-13) is in a pre-compressed or natural state.

7. The variable wing rib according to claim 2, characterized in that, A chute is opened on the flexible skin (4-1), and a fastener for positioning the flexible skin (4-1) on the middle rib plate (3) is arranged in the chute. The rod body of the fastener is connected to the corresponding middle rib plate (3), and its cap body contacts the flexible skin (4-1).

8. The variable wing rib according to claim 1, characterized in that, The first rib plate (1) forms the large end of the deformed wing rib, and the second rib plate (2) forms the small end of the deformed wing rib.

9. A method for using a variable wing rib, characterized in that, It includes the following steps: Release the corresponding multi-stable self-locking rotating joint under the action of the actuating switch (3-7). Then push or pull the flexible skin (4-1) through the skin driver to rotate the multi-stable self-locking rotating joint. When the multi-stable self-locking rotating joint runs to the required stable position, turn off the actuating switch (3-7).

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