A multi-stable flexible morphing wing based on tensile mechanism

Abstract

The application discloses a kind of multi-stable flexible deformation wing based on tension mechanism, including wing main body and deformation main body;Deformation main body includes two airfoil frames and multiple tension mechanisms sequentially arranged between two airfoil frames;Tension mechanism has spatial configuration and plane configuration, it includes a pair of deformable support components and driving rope components, the pair of support components presents plane cross structure when tension mechanism is in plane configuration, and presents spatial octahedron structure when tension mechanism is in spatial configuration;Support component includes two identical support rod members, two identical follow-up connecting plates and at least one spring;Two support rod members can be switched between V-shaped and linear under the driving of rope component;Support rod member has first end and second end, the first end of two support rod members mutually abuts and forms rolling joint.The application has the advantages of light weight, deployable and self-balancing.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wings, in particular to a multi-stable flexible morphing wing based on a tensile mechanism. BACKGROUND

[0002] With the continuous innovation and development of science and technology, aerospace equipment is also constantly innovating, and the performance requirements of aircraft and other equipment are also continuously updating and changing. The traditional aircraft has encountered a bottleneck under the new demands of higher flight performance, more complex task requirements, and heavier flight conditions. The morphing wing technology undoubtedly becomes a new breakthrough for improving the flight performance of the aircraft.

[0003] Compared with the traditional morphing wing, the flexible morphing wing has better flexibility, can absorb part of the impact, prevent the mechanism from being damaged and failed, has strong environmental adaptability, and can meet the task requirements under various complex working conditions. In terms of realizing the rapid response of the aircraft, improving the flight performance of the aircraft, improving the fuel efficiency of the aircraft, ensuring the safety of the aircraft flight, and improving the combat performance of the military fighter, the flexible morphing wing technology has great potential. The tensegrity structure has the performance characteristics of light weight, foldable, uniform load on internal components, small motion inertia, large motion coupling degree, instantaneous mobility, and variable stiffness. In the flexible morphing wing that needs to realize rapid deformation motion, the tensegrity is not only a new design idea, but also a strong candidate.

[0004] The morphing wing based on the tensegrity structure in the prior art can be divided into two types, which are based on the planar tensegrity structure and the spatial tensegrity structure for the design of the morphing wing. The tensegrity morphing wing obtained by the prior art is mostly realized by stacking and splicing multiple tensegrity units to realize the internal skeleton of the entire wing, and the contraction of different ropes is used to realize the deformation motion of the entire wing. The configuration of the tensegrity structure is not changed in the process of the deformation motion of the wing. For example, the Chinese patent document 2016109375454 discloses a distributed driving tensegrity morphing wing, the basic unit of which is a planar tensegrity structure. Through the distributed tensegrity driving of two layers of three units, the desired morphing wing motion can be finally realized.

[0005] In the morphing wing such as the prior art described above, the deformable wing based on the tensegrity structure mostly has single deformation capability, and is mostly a variable wing camber wing. There are few tensegrity structure wings that can realize other motion deformations of the wing. In the actual application of the morphing wing, it is often necessary to make corresponding adjustments according to different flight environments and flight forms. The variable wing camber wing has certain limitations. The number of drives required for the tensegrity morphing wing that can realize various wing deformation motions is relatively large, and is mostly concentrated on the wing structure, which to some extent weakens the advantage of light weight of the tensegrity structure. SUMMARY

[0006] In view of the deficiencies of the prior art, the main purpose of the present application is to provide a multi-stable flexible morphing wing based on a tension mechanism, which has the advantages of light weight, deployability and self-balancing.

[0007] In order to achieve the above main purpose, the present application provides a multi-stable flexible morphing wing based on a tension mechanism, comprising a wing body and a morphing body; the morphing body comprises two airfoil frames and a plurality of tension mechanisms arranged between the two airfoil frames in sequence;

[0008] The tension mechanism has a spatial configuration and a planar configuration, and comprises a pair of deformable support assemblies and a rope assembly for driving, the pair of support assemblies present a planar cross structure when the tension mechanism is in the planar configuration, and present a spatial octahedral structure when the tension mechanism is in the spatial configuration;

[0009] The support assembly comprises two identical support rods, two identical follow-up connecting plates and at least one spring;

[0010] The two support rods can be switched between V-shaped and straight-line shapes under the driving of the rope assembly; the support rod has a first end and a second end, and the first ends of the two support rods abut each other and form a rolling joint;

[0011] The first end of the support rod comprises a first plane forming an end face, a curved surface connected with the first plane, and a second plane connected with the curved surface, and the first plane and the second plane are located on opposite sides of the curved surface; the second planes of the two support members abut each other when the two support members are in the V-shaped state, and the first planes of the two support members abut each other when the two support members are in the straight-line state;

[0012] A through slot is arranged at the first end of the support rod, and the two follow-up connecting plates are arranged on opposite sides of the two support rods by connecting pieces penetrating through the through slot; wherein the connecting pieces are movable relative to the through slot, so that the support rod can rotate relative to the follow-up connecting plate;

[0013] The two ends of the spring are connected to the two support rods, respectively, for keeping the first ends of the two support rods abutting each other and quickly switching between the V-shaped and straight-line shapes.

[0014] According to a specific embodiment of the present application, the spring is always stretched during the shape switching process of the two support rods.

[0015] According to a specific embodiment of the present application, the elastic potential energy of the spring during the shape switching process is always higher than the elastic potential energy when the tension mechanism is in the spatial configuration and the planar configuration.

[0016] According to an embodiment of the present application, a limiting platform corresponding to the follow-up connecting plate is arranged at the first end of the support rod; when the two support rods are switched to the V shape, the follow-up connecting plate abuts against the limiting platform, so that the two support rods are kept at the set angle position.

[0017] According to an embodiment of the present application, a flexible belt is arranged on the end face of the first end of the support rod; the flexible belts of the two support rods are connected to each other.

[0018] According to an embodiment of the present application, the rope assembly comprises a first rope, a second rope and a third rope.

[0019] The first rope is a combined rope, which has four parts, each of which is a sub-rope capable of being contracted and lengthened; the two ends of the sub-rope are connected to the two follow-up connecting plates in the two support assemblies, and the sub-rope passes through the second ends of the two adjacent support rods in the two support assemblies in sequence; wherein, when the first rope is contracted, the tensioning mechanism can be driven to change from the planar configuration to the spatial configuration.

[0020] The second rope and the third rope extend along the length direction of the two support rods and are arranged on the opposite outer sides of the support rods; wherein, when the first rope is lengthened to the specified length, the second rope and the third rope are contracted to drive the tensioning mechanism to change from the spatial configuration to the planar configuration.

[0021] Further, the second end of the support rod is provided with a plurality of through holes, and the opposite outer side of the support rod is provided with a rope positioning part; the second rope and the third rope can pass through the rope positioning part.

[0022] Further, the rope assembly further comprises a guide pulley, which is arranged on the wing-shaped frame.

[0023] According to an embodiment of the present application, the number of tensioning mechanisms is three or more; the three or more tensioning mechanisms are controlled by independent controllers to control the tensioning and loosening of the rope assemblies in the tensioning mechanisms.

[0024] According to an embodiment of the present application, the deformed main body is attached to the wing tip of the wing main body.

[0025] The present application has the following advantages:

[0026] The flexible deformable wing of this invention is implemented based on a tensioning mechanism design. This mechanism facilitates the transformation between spatial and planar configurations, possessing the advantages and characteristics of a tensioning mechanism and enabling the conversion between multiple stable states of the deformable wing. The bistable tensioning mechanism in this invention, through stacking, can achieve various motion transformations of the wing, allowing it to exhibit a retracted state, a variable wingtip state, and a stretched state. Compared to existing technologies, this invention offers advantages such as light weight, deployability, self-balancing, and high flexibility, while also exhibiting high flexibility and environmental adaptability.

[0027] To more clearly illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0028] Figure 1 This is a structural diagram of an embodiment of the flexible deformable wing of the present invention;

[0029] Figure 2 It is a structural diagram of the deformed main body;

[0030] Figure 3 This is a schematic diagram of a tensioning mechanism;

[0031] Figure 4 This is a structural diagram of the tensioning mechanism;

[0032] Figure 5 This is a structural diagram of the supporting components;

[0033] Figure 6 This is a structural diagram of the supporting rods;

[0034] Figure 7 This is a structural diagram of a flexible deformable wing exhibiting a variable wingtip state.

[0035] Figure 8 yes Figure 7 A state diagram of the deformed main body;

[0036] Figure 9 This is a structural diagram of a flexible deformable wing exhibiting a stretched state.

[0037] Figure 10 yes Figure 9 A state diagram of the deformed main body.

[0038] Figure 11 This is a coordinate diagram of the spatial configuration of the tensioning mechanism;

[0039] Figure 12 This is a coordinate diagram of the planar configuration of the tensioning mechanism;

[0040] Figure 13 This is a schematic diagram of the V-bar dimensions; DETAILED DESCRIPTION

[0041] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details set forth in this description.

[0042] The embodiment of the present application is based on a multi-stable flexible morphing wing with tensioning mechanism as shown in Figures 1-2 which comprises a wing body 10 and a morphing body 20; the morphing body 20 comprises two airfoil frames 21 and a plurality of tensioning mechanisms 22, the number of the tensioning mechanisms 22 is preferably three or more, and the plurality of tensioning mechanisms 22 are sequentially arranged between the two airfoil frames 21. Among them, the morphing body 20 is attached to the wing tip of the wing body 10; in an alternative embodiment, the morphing body 20 can also be formed inside the wing body 10 to form an internal skeleton of the wing, which will not be expanded here.

[0043] As shown in Figure 3 , the tensioning mechanism 22 can form two different structural morphologies, which are spatial morphology and planar morphology, and the two morphologies correspond to two different configurations, which are spatial configuration and planar configuration, and each configuration corresponds to a topological structure. By adjusting and changing the compression member, the transformation from the spatial configuration tensioning mechanism 22 to the planar configuration tensioning mechanism 22 can be realized. Among them, the tensioning mechanism 22 is in a balance state of the mechanism in the two configurations, and the two configurations should be at the local potential minimum point of the tensioning mechanism 22, and finally a flexible tensioning mechanism 22 with bistability can be obtained, and the two stable states are the two configurations of the tensioning mechanism 22.

[0044] As shown in Figure 4 , the tensioning mechanism 22 comprises a pair of deformable support assemblies and a rope assembly for driving; please combine Figure 3 , the pair of support assemblies present a planar cross structure when the tensioning mechanism 22 is in the planar configuration, and present a spatial octahedral structure when the tensioning mechanism 22 is in the spatial configuration;

[0045] As shown in Figure 5 , the support assembly comprises two identical support rods 221, two identical follow-up connecting plates 222 and at least one spring 223; the two support rods 221 can be switched between V-shaped and straight line shape under the driving of the rope assembly; the support rod 221 has a first end 221a and a second end 221b, and the first ends of the two support rods 221 abut each other and form a rolling joint.

[0046] In an optional embodiment, a flexible band is arranged on the end face of the first end of the support rod member 221, and the flexible bands of the two support rod members 221 are connected to each other in cooperation; wherein the flexible band is made of polyurethane rubber for example, and the two ends of the flexible band are fixed on the two support rod members 221 respectively, and the first ends of the support rod members 221 are cooperatively connected to form the rolling joint described above; compared with the traditional bolt connection, the contact area of this connection mode is larger, and it can bear larger load, so that the relative sliding of the two support rod members 221 is avoided when the two support rod members 221 move, and the friction is lower.

[0047] As shown in Figure 6 the first end of the support rod member 221 includes a first plane 2211 forming an end face, a curved surface 2212 connected to the first plane 2211, and a second plane 2213 connected to the curved surface 2212, and the first plane 2211 and the second plane 2213 are located on opposite sides of the curved surface 2212; the second planes 2213 of the two support members abut each other when the two support members are in a V-shaped state, and the first planes 2211 of the two support members abut each other when the two support members are in a straight line state.

[0048] Further, a through slot 2214 is arranged at the first end of the support rod member 221, and the through slot 2214 specifically penetrates the support rod member 221 in the thickness direction; the two follow-up connecting plates 222 are arranged on opposite sides of the two support rod members 221 through the connecting pieces 224 penetrating the through slot 2214; wherein the connecting piece 224 is movable relative to the through slot 2214, so that the support rod member 221 can rotate relative to the follow-up connecting plate 222; specifically, the connecting piece 224 is preferably a bolt.

[0049] The number of springs 223 is preferably two, and the two springs 223 are symmetrically arranged on opposite sides of the two support rod members 221; wherein the two ends of the spring 223 are connected to the two support rod members 221 respectively, for keeping the first ends of the two support rod members 221 abutting and quickly switching between the V-shaped and straight line shapes. Preferably, the spring 223 is always stretched during the shape switching process of the two support rod members 221, and the elastic potential energy of the spring 223 during the shape switching process is always higher than the elastic potential energy when the spring 223 is in the spatial configuration and the planar configuration. In the embodiment, the addition of the spring 223 ensures that the tensioning mechanism 22 can quickly change from the spatial shape to the planar shape; by designing the spring 223 and the structure size, the tensioning mechanism 22 is respectively at the minimum point of the elastic potential energy in the spatial shape and the planar shape, and the elastic potential energy of the spring 223 is always higher than the two stable shapes of the tensioning mechanism 22 during the shape conversion, so it always tends to the two shapes during the movement, which ensures the rapidity and stability of the shape switching of the tensioning mechanism 22.

[0050] Please continue to refer to Figure 5The first end of the support rod member 221 is provided with a limiting table 225 corresponding to the follow-up connecting plate 222; when the two support rod members 221 are switched to the V shape, the follow-up connecting plate 222 abuts against the limiting table 225, so that the two support rod members 221 are kept at the set angle position. The advantage of this arrangement is that the two support rod members 221 in the support assembly can be better kept at the required angle in the space form, which is beneficial to improve the stability of the flexible double-stable tension mechanism 22 in maintaining the form.

[0051] The deformed body 20 in the embodiment can be directly attached at the wing tip of the original wing for use, that is, it can be directly applied to an aircraft that needs to achieve rapid and smooth deformation. By simultaneously driving the tension mechanism 22 to flexibly switch between the “space-plane” two forms, the requirement for rapid wing tip deformation and rapid wing stretching during flight is met.

[0052] Please continue to refer to Figures 3-5 The rope assembly includes a first rope 226, a second rope 227, a third rope 228, and a plurality of guide pulleys 229 (see Figure 2 ); wherein the plurality of guide pulleys 229 are arranged on the airfoil frame 21 to guide the first rope 226, the second rope 227, and the third rope 228, respectively.

[0053] The first rope 226 is a combined rope, which has four parts, each of which is a sub-rope that can be contracted and lengthened. The two ends of the sub-rope are connected to the two follow-up connecting plates 222 in the two support assemblies, and the sub-rope passes through the second ends of the two adjacent support rod members 221 in the two support assemblies in sequence. When the first rope 226 is contracted, it can drive the tension mechanism 22 to transform from the plane configuration to the space configuration. In other embodiments, the connection mode of the first rope 226 can be set as needed, as long as it can drive the tension mechanism 22 to transform from the plane configuration to the space configuration.

[0054] The second rope 227 and the third rope 228 extend along the length direction of the two support rod members 221 and are arranged on the opposite outer sides of the support rod members 221. When the first rope 226 is lengthened to a specified length, the second rope 227 and the third rope 228 are contracted to drive the tension mechanism 22 to transform from the space configuration to the plane configuration.

[0055] In the embodiment, three or more tension mechanisms 22 are controlled by independent controllers to control the tightening and loosening of the rope assemblies therein, thereby realizing multiple attitudes of the deformed body 20. When all the tension mechanisms 22 are in the space configuration, the flexible wing (deformed body 20) is in the contracted state, as shown in Figure 1 When the tension mechanisms 22 are all in the plane configuration, the flexible wing (deformed body 20) is in the stretched state, as shown inFigures 9-10 is shown; when two tensioning mechanisms 22 close to the wing tip are in the spatial configuration and the other tensioning mechanism 22 connecting with the wing body 10 is in the planar configuration, the flexible wing (deformation body 20) is in the wing tip deformation state, as shown in Figures 7-8 . In use, the required motion form of the flexible wing can be achieved through the deformation motion of different tensioning mechanisms 22.

[0056] The second end of the support rod 221 in the embodiment is provided with a plurality of through holes 2215, which can be used for the rope to pass through and can also be used for connection when adjacent tensioning mechanisms 22 are spliced.

[0057] Please continue to refer to Figure 4 and Figure 6 , the support rod 221 is further provided with a rope positioning part, for example, an upper positioning plate 2216 (see Figure 2 ) provided on the support rod 221. The second rope 227 and the third rope 228 can pass through the rope positioning part, so as to reduce the interference phenomenon that the ropes can cause to the maximum extent.

[0058] The calculation process of the exemplary design parameters of the tensioning mechanism 22 in the embodiment is as follows:

[0059]

[0060] Let x i , y i , and z i represent the three coordinate values of node i, the coordinate vector n i of node i in the spatial configuration and the coordinate vector n′ i of node i in the planar configuration can be respectively represented as:

[0061] n i = {x i , y i , z i} T

[0062] n′ i = {x′ i , y′ i , z′ i} T

[0063] The coordinate vectors of the nodes at the two ends of the cable unit can be combined to obtain the direction vector of the cable unit k:

[0064] s k = {n i -n j}

[0065] The node matrix N of the tensioning mechanism in spatial configuration and the node matrix N′ of the planar configuration can be expressed as follows:

[0066]

[0067]

[0068] Figure 11 The diagram shows the coordinates of the tensioning mechanism in configuration one, i.e., the spatial configuration. The diagram defines the mechanism as having 6 nodes (nodes 1-6) and 10 units, including 2 bar units (V1 V2) and 8 cable units (s1-s8). The angle formed by the same "V" bar is defined as 2α. The angle between adjacent cable units at the upper and lower ends, i.e., the angle between s5 and s6 (or the angle between s7 and s8), is 2β.

[0069] The structural dimensions of the “V” bar are as follows: Figure 13 As shown, the length of each side of the "V" rod is defined as l. b The lengths of the cable elements at the top and bottom ends are: |s8|=|s7|=|s6|=|s5|=l s And the designed tensioning mechanism satisfies the following constraints: l b sin(α)=l s cos(β);

[0070] The node matrix of the tensioning mechanism in its spatial configuration can be obtained as follows:

[0071]

[0072] Calculate the cable elements of the tensioning mechanism in its spatial configuration:

[0073]

[0074] Figure 12 This is a coordinate diagram of the tensioning mechanism in configuration two, i.e., the planar configuration. In this configuration, the mechanism degenerates from a spatial mechanism to a planar mechanism. The lateral cable elements s′5, s′6, s′7, and s′8 remain in a relaxed state in the planar configuration, and their influence on the mechanism can be ignored. Therefore, the planar configuration of the mechanism can be simplified to a tensioning structure with 4 nodes and 6 elements (4 cable elements and 2 rod elements). The total length of the compression member in the planar configuration is 2l. b Then the node matrix of the tensioning mechanism in a planar configuration can be represented as:

[0075]

[0076] Combining the node coordinate vectors and the above formulas, the coordinate vectors of the cable elements in the planar configuration can be obtained as follows:

[0077]

[0078] The mechanism design parameters of the tensioning mechanism can be obtained by calculation as follows:

[0079] Table 1 Parameter selection of structure design

[0080]

[0081] Although the present application has been depicted by way of example with reference to the above embodiments, it is to be understood that the above embodiments are merely illustrative of the embodiments of the present application and should not be construed as limiting the scope of protection of the present application, i.e. any substitutions or changes made by those skilled in the art in accordance with the present application should also be encompassed by the scope of protection of the claims of the present application.

Claims

1. A multi-stable flexible morphing wing based on tensile mechanisms, comprising a wing body and a morphing body; characterized in that: The deformed body comprises two airfoil frames and a plurality of tensioning mechanisms arranged between the two airfoil frames in sequence; The tensioning mechanism has a spatial configuration and a planar configuration, and comprises a pair of deformable support assemblies and a driving rope assembly, the pair of support assemblies present a planar cross structure when the tensioning mechanism is in the planar configuration, and present a spatial octahedron structure when the tensioning mechanism is in the spatial configuration; The support assembly comprises two identical support rods, two identical follower connecting plates and at least one spring; The two support rods can be switched between V-shaped and straight-line shapes under the driving of the rope assembly; the support rods have first ends and second ends, and the first ends of the two support rods abut against each other and form a rolling joint; The first end of the support rod comprises a first plane forming an end face, a curved surface connected with the first plane, and a second plane connected with the curved surface, and the first plane and the second plane are located on opposite sides of the curved surface; the second planes of the two support rods abut against each other when the two support rods are in the V-shaped state, and the first planes of the two support rods abut against each other when the two support rods are in the straight-line state; A through slot is arranged at the first end of the support rod, and the two follower connecting plates are arranged on opposite sides of the two support rods through connecting pieces penetrating through the through slot; the connecting pieces can move relative to the through slot, so that the support rod can rotate relative to the follower connecting plates; The two ends of the spring are connected with the two support rods respectively, for keeping the first ends of the two support rods abutting against each other and quickly switching between V-shaped and straight-line shapes; The rope assembly comprises a first rope, a second rope and a third rope; The first rope is a combined rope, which has four parts, each part being a sub-rope that can be contracted and lengthened; the two ends of the sub-rope are connected with two follower connecting plates in two support assemblies respectively, and the sub-rope passes through the second ends of two adjacent support rods in two support assemblies in sequence; when the first rope is contracted, the tensioning mechanism can be driven to change from the planar configuration to the spatial configuration; The second rope and the third rope extend along the length direction of the two support rods and are arranged on opposite outer sides of the support rods; when the first rope is lengthened to a specified length, the second rope and the third rope can be contracted to drive the tensioning mechanism to change from the spatial configuration to the planar configuration.

2. The tensegrity-based, multi-stable, flexible morphing wing of claim 1, wherein: The spring is always stretched during the shape switching process of the two support rods.

3. The tensegrity-based, multi-stable, flexible morphing wing of claim 2, wherein: The elastic potential energy of the spring during the shape switching process is always higher than that when the tensioning mechanism is in the spatial configuration and the planar configuration.

4. The tensegrity-based, multi-stable, flexible morphing wing of claim 1, wherein: A limiting table corresponding to the follower connecting plate is arranged at the first end of the support rod; when the two support rods are switched to the V-shaped state, the follower connecting plate abuts against the limiting table, so that the two support rods are kept at a set angle position.

5. The tensegrity-based, multi-stable, flexible morphing wing of claim 1, wherein: The end face of the first end of the support rod member is provided with a flexible belt, and the flexible belts of the two support rod members are connected to each other.

6. The tensegrity-based, multi-stable, flexible morphing wing of claim 1, wherein: The opposite outer sides of the support rod member are provided with rope positioning portions, and the second rope and the third rope can pass through the rope positioning portions.

7. The tensegrity-based, morphing wing of claim 1, wherein: The rope assembly further comprises a guide pulley arranged on the airfoil frame.

8. The tensegrity-based, multi-stable, flexible morphing wing of claim 1, wherein: The number of the tensioning mechanisms is three or more, and the three or more tensioning mechanisms are controlled by independent controllers to control the tensioning and loosening of the rope assemblies in the tensioning mechanisms.

9. The tensegrity-based, morphing wing of claim 1, wherein: The deformed body is attached to the wing tip of the wing body.

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