Single-degree-of-freedom multi-configuration morphing mechanism and morphing wing

Abstract

This invention discloses a single-degree-of-freedom multi-configuration variator mechanism and a variator wing. The single-degree-of-freedom multi-configuration variator mechanism is formed by four closed-loop link units arranged in two approximately symmetrical networks. Each closed-loop link unit is a 6R mechanism capable of switching between a planar motion configuration and a Bennett motion configuration, comprising a first, second, third, fourth, fifth, and sixth link connected end-to-end. These links are rotatably connected via revolute joints R1, R2, R3, R4, R5, and R6. In the singular position where the closed-loop link unit switches between the planar motion configuration and the Bennett motion configuration, the rotation axes of revolute joints R1, R2, R4, and R5 are parallel to each other, and R2, R3, R4, and R5 lie in the same plane. The rotation axes of revolute joints R3 and R6 always intersect at a single point. This invention has the advantages of good stability and high reliability.

Description

Technical Field

[0001] This invention relates to the field of aviation, specifically to a single-degree-of-freedom multi-configuration variator mechanism and a variator wing. Background Technology

[0002] Variants-mounted mechanisms designed to achieve wing deformation have become a research hotspot in recent years, especially those with multiple deformation capabilities, high stiffness, lightweight construction, and simple control methods. For aircraft that can optimize aerodynamic performance and reduce fuel consumption by adjusting wing shape to improve operational performance and flight economy in different flight missions or environments, reliability is crucial for variants-mounted mechanisms. Furthermore, variants-mounted mechanisms applied to variant wings must simultaneously possess high stiffness, light weight, high precision, and multiple configurations.

[0003] Most existing multi-configuration variator wings employ multiple drive mechanisms, which complicates control strategies and increases the overall weight of the wing. Their complex linkages and significant motion redundancy make the mechanism prone to jamming, deformation, and failure, failing to meet the stability requirements of aerospace mechanisms. In general, the main shortcomings of existing variator mechanisms applied to variator wings are as follows: 1) Limited variability, only capable of one type of wing deformation; 2) Multi-configuration variator mechanisms generally suffer from complex control methods, increased mass, and unreliable switching between configurations under high load requirements due to the use of multiple drive mechanisms; 3) Many variator wings are not composed of multiple basic units, resulting in a generally poor wing camber gradient. Due to these shortcomings, existing variator wings limit the types of missions an aircraft can perform and its ability to adapt to different environments. Summary of the Invention

[0004] To at least partially address the shortcomings of the prior art, the main objective of this invention is to provide a single-degree-of-freedom multi-configuration morphing mechanism and a morphing wing. In the morphing mechanism, all kinematic pairs are revolute pairs, and the morphing switching is achieved by locking and unlocking the revolute pairs at singular positions of the mechanism, which has the advantages of good stability and high reliability.

[0005] To achieve the above-mentioned main objectives, the first aspect of the present invention discloses a single-degree-of-freedom multi-configuration variant mechanism, which is formed by four closed-loop rod units through two approximately symmetrical networking processes.

[0006] The closed-loop linkage unit is a 6R mechanism that can switch between a planar motion configuration and a Bennett motion configuration. It includes a first link, a second link, a third link, a fourth link, a fifth link, and a sixth link connected end to end in sequence. The first link, the second link, the third link, the fourth link, the fifth link, and the sixth link are rotatably connected by revolute joints R1, R2, R3, R4, R5, and R6 in sequence.

[0007] The closed-loop linkage unit is in a singular position switching between a planar motion configuration and a Bennett motion configuration. The rotation axes of revolute joints R1, R2, R4, and R5 are parallel to each other, and revolute joints R2, R3, R4, and R5 are in the same plane. The rotation axes of revolute joints R3 and R6 always intersect at a single point. At this time, with the first link as the fixed link, revolute joint R1 as the driving link, revolute joints R2 and R3 as locking and unlocking revolute joints, and revolute joints R4, R5, and R6 as following revolute joints, the closed-loop linkage unit can be switched to a planar motion configuration by locking revolute joint R3 and unlocking revolute joint R2, and the closed-loop linkage unit can be switched to a Bennett motion configuration by locking revolute joint R2 and unlocking revolute joint R3.

[0008] In the closed-loop linkage unit, when in a planar motion configuration, the fourth link, which is far from the first link, can be driven to move back and forth by the forward and reverse rotation of the drive pair R1. When in a Bennett motion configuration, the fourth link, which is far from the first link, can be driven to move in a bending motion by the forward and reverse rotation of the drive pair R1.

[0009] According to one specific embodiment of the present invention, the first and fourth rods have the same shape, the second and fifth rods have the same shape, and the third and sixth rods have the same shape.

[0010] Furthermore, the first and fourth links are set as L-shaped links, the second and fifth links are set as L-shaped bars, and the third and sixth links are straight bars, so that the closed-loop link unit presents a Z-shaped form when in a bifurcated configuration.

[0011] According to one specific embodiment of the present invention, the corresponding first, fourth, or fifth links in adjacent closed-loop linkage units are connected together to share a revolute joint R4 or R6.

[0012] According to a specific embodiment of the present invention, after the four closed-loop linkage units are networked, the revolute joint R1 in one of the closed-loop linkage units is a driving joint, the revolute joints R2 and R3 are locking and unlocking revolute joints, and the revolute joints R1, R2 and R3 in the other three closed-loop linkage units are all follower revolute joints, so that the four closed-loop linkage units have 1 degree of freedom.

[0013] According to a specific embodiment of the present invention, when the closed-loop linkage unit is in a singular position, the included angle between the rotating joints R2 and R3 is the same as the included angle between the rotating joints R5 and R6.

[0014] Furthermore, when the closed-loop linkage unit is in a singular position, the included angle between revolute joints R2 and R3 and the included angle between revolute joints R5 and R6 are both 45°.

[0015] A second aspect of the present invention provides a variant wing, including a plurality of ribs and an airfoil adjustment unit for connecting two adjacent ribs, wherein the airfoil adjustment unit includes a control module and a single-degree-of-freedom multi-configuration variant mechanism as described above, the control module being used to control the single-degree-of-freedom multi-configuration variant mechanism to switch to a planar motion configuration or a Bennett motion configuration to change the sweep angle and camber of two adjacent ribs.

[0016] According to one specific embodiment of the present invention, the number of ribs is three or more, and the three or more ribs are connected in series through different airfoil adjustment units.

[0017] This invention has the following advantages: It proposes a single-degree-of-freedom multi-configuration variator mechanism and a variator wing with good stability and high reliability. The single-degree-of-freedom multi-configuration variator mechanism can achieve both in-plane sweep angle and out-of-plane bending motion modes without increasing its degree of freedom. It achieves multiple functions in one machine without increasing its control difficulty and weight. The base unit of the variator mechanism is a 6R mechanism composed of six revolute joints. The selection of the mechanism's motion configuration switching mode adopts a mechanical method of locking and unlocking the revolute joints rather than a control method involving relatively complex speed or even acceleration planning, which has the advantages of simple and efficient control.

[0018] Furthermore, due to the characteristics of the multi-closed-loop mechanism and its inherent near-symmetry, the distribution of external forces and driving forces on this variant mechanism is relatively reasonable, resulting in high stiffness and load-bearing capacity. The structural characteristics of this variant mechanism allow it to be connected with wing ribs to form a tandem multi-unit variant wing, which enhances the camber gradient effect of the variant wing. At the same time, due to this modular feature, the maintenance and repair of the wing are greatly facilitated.

[0019] 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

[0020] Figure 1 Assembly diagram of the variant wing of this invention;

[0021] Figure 2 This is a structural diagram of the variant mechanism of the present invention in a singular position;

[0022] Figure 3 This is a schematic diagram of a closed-loop linkage unit;

[0023] Figure 4 It is the configuration of the 6R basic unit and the first local coordinate diagram of each revolute joint;

[0024] Figure 5 This is the configuration of the 6R basic unit and the second local coordinate diagram of each revolute joint;

[0025] Figure 6 This is a schematic diagram of the configuration switching of the 6R basic unit;

[0026] Figure 7 This is a schematic diagram showing the switching of various configurations of the variant mechanism of the present invention;

[0027] Figure 8 This is a comparison diagram of the deformation methods and types of the variant wing of the present invention. Detailed Implementation

[0028] Many specific details are set forth in the following description in conjunction with embodiments in order to provide a full understanding of the invention. However, it should be understood that the following embodiments and detailed description are for illustrative purposes only and do not limit the scope of protection of the invention.

[0029] The variant wing provided in the embodiments of the present invention, such as Figure 1 As shown, it includes multiple ribs 10 and airfoil adjustment units 20 for connecting adjacent ribs 10; wherein, the airfoil adjustment unit 20 includes a control module and a single-degree-of-freedom multi-configuration variant mechanism 30, the single-degree-of-freedom multi-configuration variant mechanism 30 having a planar motion configuration or a Bennett motion configuration, the control module is used to control the single-degree-of-freedom multi-configuration variant mechanism 30 to switch to the planar motion configuration or the Bennett motion configuration, thereby changing the sweep angle and camber of adjacent ribs 10. The number of ribs 10 is three or more, and the three or more ribs 10 are connected in series through different airfoil adjustment units 20.

[0030] The single-degree-of-freedom multi-configuration variant mechanism 30 in this embodiment includes four closed-loop link units, namely, a first closed-loop link unit 30a, a second closed-loop link unit 30b, a third closed-loop link unit 30c, and a fourth closed-loop link unit 30d. The first closed-loop link unit 30a, the second closed-loop link unit 30b, the third closed-loop link unit 30c, and the fourth closed-loop link unit 30d are formed by two approximately symmetrical network configurations to create the single-degree-of-freedom multi-configuration variant mechanism 30. The specific structure of the closed-loop link unit will be described below using the first closed-loop link unit 30 as an example.

[0031] The first closed-loop linkage unit 30a is a 6R mechanism that can switch between planar motion configuration and Bennett motion configuration, such as Figure 2-3 As shown, it includes a first member 31, a second member 32, a third member 33, a fourth member 34, a fifth member 35, and a sixth member 36 connected end to end in sequence. The first member 31, the second member 32, the third member 33, the fourth member 34, the fifth member 35, and the sixth member 36 are rotatably connected by revolute joints R1, R2, R3, R4, R5, and R6 in sequence.

[0032] In this configuration, the first closed-loop linkage unit 30a is in a singular position switching between a planar motion configuration and a Bennett motion configuration. The rotation axes of revolute joints R1, R2, R4, and R5 are parallel to each other, and revolute joints R2, R3, R4, and R5 are in the same plane. Furthermore, the rotation axes of revolute joints R3 and R6 always intersect at a single point. At this time, with the first link 31 as the fixed link, revolute joint R1 as the driving joint, revolute joints R2 and R3 as locking / unlocking revolute joints, and revolute joints R4, R5, and R6 as following revolute joints, the control module can switch the first closed-loop linkage unit 30a to the planar motion configuration by locking revolute joint R3 and unlocking revolute joint R2, and can switch the first closed-loop linkage unit 30a to the Bennett motion configuration by locking revolute joint R2 and unlocking revolute joint R3. The control module in this embodiment can be configured as needed, such as using an electric drive module, etc., which is not limited here and will not be elaborated further.

[0033] When the first closed-loop linkage unit 30a is in a planar motion configuration, the forward and reverse rotation of the drive pair R1 can drive the fourth link 34, which is far away from the first link 31, to move back and forth. When the first closed-loop linkage unit 30a is in a Bennett motion configuration, the forward and reverse rotation of the drive pair R1 can drive the fourth link 34, which is far away from the first link 31, to move in a bending motion.

[0034] In this embodiment, the locked / unlocked state of the kinematic pairs of the single-degree-of-freedom multi-configuration variant mechanism 30 obtained by networking is the same as that of the first closed-loop linkage unit 30a. When the four closed-loop linkage units are networked, the corresponding first link 31, fourth link 34 or fifth link 35 in adjacent closed-loop linkage units are connected together (e.g., connected in a shared manner) to share the revolute joint R4 or R6. Among them, after the four closed-loop linkage units are networked, the revolute joint R1 in the first closed-loop linkage unit 30a is the driving joint, and the revolute joints R2 and R3 are the locked / unlocked revolute joints. The revolute joints R1, R2 and R3 in the other three closed-loop linkage units (30b, 30c, 30d) are all follower revolute joints, so that the degree of freedom after the four closed-loop linkage units are networked is still 1. Therefore, the control difficulty is not increased by increasing the degree of freedom due to the formation of the network.

[0035] like Figure 7 The diagram showing the switching between the various configurations of the variant mechanism illustrates that when the single-degree-of-freedom multi-configuration variant mechanism 30 enters the planar motion configuration, the fourth link away from the first link 31 moves forward by driving the auxiliary link R1 to rotate counterclockwise, and conversely, the fourth link away from the first link 31 moves backward by driving the auxiliary link R1 to rotate clockwise. When the single-degree-of-freedom multi-configuration variant mechanism 30 enters the Bennett motion configuration, the fourth link away from the first link 31 (the entire variant mechanism) bends upward by driving the auxiliary link R1 to rotate counterclockwise, and the fourth link away from the first link 31 (the entire variant mechanism) bends downward by driving the auxiliary link R1 to rotate clockwise.

[0036] In this embodiment, after determining the configuration of the closed-loop linkage unit, the link parameters of the 6R mechanism are determined as follows: the configuration of the 6R mechanism and the local coordinate system definitions at each revolute joint are shown in the appendix. Figure 4-5 As shown, according to the DH notation, θ is taken as... i (i = 1, 2, 3, 4, 5, 6) represent the joint angle variables at each revolute joint. The remaining DH parameters of this mechanism are as follows:

[0037] α 12 =α 45 =0,

[0038] a 23 =a 56 =0,a 34 =a 61 =2l

[0039] d1=d4=-l, d2=d5=0,

[0040] Where, α i(i+1) (i=1,2,3,4,5) and α 61 Indicates the angle of twist between adjacent revolute joints about the axis; a i(i+1) (i=1,2,3,4,5) and a 61 This represents the equivalent length of each link, i.e., the length of the common perpendicular between adjacent revolute axes; d i (i = 1, 2, 3, 4, 5, 6) represents the translation distance between the x-axis of the two local coordinate systems at each rotational joint axis. All non-zero values ​​in the above parameters are in the appendix. Figure 4-5 The bid was successful.

[0041] By solving the closed-loop DH equations of the mechanism, the bifurcation points (singular positions) of the planar motion branches and the Bennett motion of the 6R mechanism are obtained. Figure 4-5 Under the definition of the local coordinate system, it is:

[0042] θ3=θ6=0

[0043] At this singular position (bifurcation point), by locking kinematic pair R3 / S3 and unlocking kinematic pair R2 / S2, the planar kinematic configuration can be entered; by locking kinematic pair R2 / S2 and unlocking kinematic pair R3 / S3, the Bennett kinematic configuration can be entered. The configurational transformation is shown in the attached figure. Figure 6 As shown.

[0044] Under planar motion configuration, the following conditions are satisfied:

[0045]

[0046] Under the Bennett motion configuration, the following conditions are satisfied:

[0047]

[0048] Figure 4-5 The parameters of the 6R mechanism are shown. To meet the symmetrical structure required for networking, l1 (second link 32) and l4 (fifth link 35) in the closed-loop link unit in the embodiment are changed from straight rods to bent rods. The above changes do not change the DH parameters of each link and the geometric relationship between the rotating joints.

[0049] Furthermore, when the closed-loop linkage unit is in a singular position, the included angle between the rotating joints R2 and R3 is the same as the included angle between the rotating joints R5 and R6; in the embodiment, when the closed-loop linkage unit 30a is in a singular position, the included angle between the rotating joints R2 and R3 and the included angle between the rotating joints R5 and R6 are both 45°.

[0050] Please continue reading. Figure 3 The first member 31 and the fourth member 34 have the same shape and are set as L-shaped members; the second member 32 and the fifth member 35 have the same shape and are also set as L-shaped members; the third member 33 and the sixth member have the same shape and are both set as straight members; based on the shape of each member, the closed-loop member unit 30a presents a Z-shaped form when in a bifurcated configuration.

[0051] like Figure 8 As shown in the embodiment, by utilizing the characteristics of the network planar motion, the revolute joints R1 in the four closed-loop rod units are connected to the ribs 10 respectively. By fixing the ribs 10 connected to the two revolute joints R1 on the same side, the forward and backward movement between the two ribs 10 can be realized to change the sweep angle. Similarly, by utilizing the characteristics of the network Bennett motion, by fixing the ribs 10 connected to the two revolute joints R1 on the same side, the continuous bending deformation of each rib 10 can be realized.

[0052] The deformable wing in the embodiment can achieve two deformation forms: variable sweep angle on the inner surface and variable camber on the outer surface. It can adapt to various flight environments such as takeoff and landing, high-altitude cruise, high-speed flight and rapid maneuvering, thereby increasing the mission types of the aircraft and improving the flight performance of the aircraft.

[0053] Although the present invention has been described above by way of embodiments, the above embodiments are only used to exemplify possible implementations of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or changes made by those skilled in the art in accordance with the present invention should also be covered by the scope of protection defined by the claims of the present invention.

Claims

1. A single-degree-of-freedom multi-configuration variant mechanism, characterized in that: The single-degree-of-freedom multi-configuration variant mechanism is formed by four closed-loop rod units through two approximately symmetrical network configurations. The closed-loop linkage unit is a 6R mechanism that can switch between a planar motion configuration and a Bennett motion configuration. It includes a first link, a second link, a third link, a fourth link, a fifth link, and a sixth link connected end to end in sequence. The first link, the second link, the third link, the fourth link, the fifth link, and the sixth link are rotatably connected by revolute joints R1, R2, R3, R4, R5, and R6 in sequence. The closed-loop linkage unit is in a singular position switching between a planar motion configuration and a Bennett motion configuration. The rotation axes of revolute joints R1, R2, R4, and R5 are parallel to each other, and revolute joints R2, R3, R4, and R5 are in the same plane. The rotation axes of revolute joints R3 and R6 always intersect at a single point. At this time, with the first link as the fixed link, revolute joint R1 as the driving link, revolute joints R2 and R3 as locking and unlocking revolute joints, and revolute joints R4, R5, and R6 as following revolute joints, the closed-loop linkage unit can be switched to a planar motion configuration by locking revolute joint R3 and unlocking revolute joint R2, and the closed-loop linkage unit can be switched to a Bennett motion configuration by locking revolute joint R2 and unlocking revolute joint R3. In the closed-loop linkage unit, when in a planar motion configuration, the fourth link, which is far from the first link, can be driven to move back and forth by the forward and reverse rotation of the drive pair R1. When in a Bennett motion configuration, the fourth link, which is far from the first link, can be driven to move in a bending motion by the forward and reverse rotation of the drive pair R1.

2. The single-degree-of-freedom multi-configuration variant mechanism according to claim 1, characterized in that: The first and fourth members have the same shape, the second and fifth members have the same shape, and the third and sixth members have the same shape.

3. The single-degree-of-freedom multi-configuration variant mechanism according to claim 2, characterized in that: The first and fourth links are set as L-shaped links, the second and fifth links are set as L-shaped bars, and the third and sixth links are straight bars, so that the closed-loop link unit presents a Z-shaped form when in a bifurcated configuration.

4. The single-degree-of-freedom multi-configuration variant mechanism according to claim 1, characterized in that: The first, fourth, or fifth links in adjacent closed-loop linkage units are connected together to share a revolute joint R4 or R6.

5. The single-degree-of-freedom multi-configuration variant mechanism according to claim 1, characterized in that: After the four closed-loop linkage units are networked, the revolute joint R1 in one of the closed-loop linkage units is a driving joint, and the revolute joints R2 and R3 are locking and unlocking revolute joints. The revolute joints R1, R2, and R3 in the other three closed-loop linkage units are all follower revolute joints, so that the four closed-loop linkage units have 1 degree of freedom.

6. The single-degree-of-freedom multi-configuration variant mechanism according to claim 1, characterized in that: When the closed-loop linkage unit is in a singular position, the included angle between revolute joints R2 and R3 is the same as the included angle between revolute joints R5 and R6.

7. The single-degree-of-freedom multi-configuration variant mechanism according to claim 6, characterized in that: When the closed-loop linkage unit is in a singular position, the included angle between revolute joints R2 and R3 and the included angle between revolute joints R5 and R6 are both 45°.

8. A variant wing, comprising a plurality of ribs and an airfoil adjustment unit for connecting two adjacent ribs, characterized in that: The airfoil adjustment unit includes a control module and a single-degree-of-freedom multi-configuration variant mechanism as described in any one of claims 1-7. The control module is used to control the single-degree-of-freedom multi-configuration variant mechanism to switch to a planar motion configuration or a Bennett motion configuration to change the sweep angle and camber of two adjacent ribs.

9. The variant wing according to claim 8, characterized in that: The number of ribs is three or more, and the three or more ribs are connected in series through different airfoil adjustment units.

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