Biomimetic variable stiffness folding and unfolding structure based on locust wing

Abstract

The application discloses a bionic variable stiffness folding and unfolding structure based on locust wings, belonging to the field of space vehicles, which is composed of a base body and folding and unfolding arrays. The base body is used for simulating the main body part of a locust; two folding and unfolding arrays are used for simulating locust wings and are symmetrically arranged on the left and right sides of the base body. The two folding and unfolding arrays are composed of a plurality of skeletons, the front ends of the skeletons can slide along the slide rails on the left and right sides of the base body, the plurality of skeletons are expanded and contracted in a fan-shaped manner, and the certainty and order of the movement between the skeletons are ensured. The adjacent skeletons are connected through a scissor linkage unfolding device, and the synchronization of the movement between the skeletons is realized. The application can realize the design of a super large expansion and contraction ratio of a spacecraft structure, has a simple and reliable expansion and contraction form and strong and stable anti-interference performance, and ensures the safe and reliable operation of the spacecraft in orbit.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of space vehicles, and particularly relates to a bionic variable stiffness folding and unfolding structure based on locust wings. BACKGROUND

[0002] In the process of continuous development of space exploration engineering, space vehicles play a pivotal role, and the structure and function of space vehicles are becoming increasingly perfect. The ability to fold and transport in a small volume and to unfold and work in a large area is the primary prerequisite for the design and performance improvement of space vehicles. Therefore, the space folding and unfolding mechanism plays an irreplaceable key role in the design process of space vehicles. Designing a new folding and unfolding mechanism with a super large folding and unfolding ratio, simple operation and reliable performance is the prerequisite for improving the performance of space vehicles.

[0003] Among existing space unfolding mechanisms, there are foldable hinged unfolding or cable-strut hinged unfolding, which is mainly suitable for truss structures and cannot be directly applied to large array space antennas. Large array unfolding structures usually realize the combination of telescopic arms and link mechanisms, but this way has a small folding and unfolding ratio, and the folding and unfolding effect is excessively dependent on the processing performance of telescopic arms, and the anti-interference ability is poor in space extreme environment.

[0004] It can be found that the existing space unfolding mechanisms generally have the following problems: small folding and unfolding ratio, which cannot adapt to the needs of performance improvement of future space vehicles; complex folding and unfolding mode, which greatly reduces the reliability and survivability of space exploration; poor interference resistance of pure rigid structure, which affects the service life and performance of space vehicles when facing complex and sudden loads.

[0005] On the other hand, there are excellent engineers in nature that are worth learning from. A small locust can fly across continents, and the weight of its wings is 1-2% of its total weight, but it exhibits super strong stability and excellent load-bearing capacity in flight, which is a structure with excellent performance. In addition, the locust wing has a large folding and unfolding ratio, and can quickly perform wing unfolding action to quickly unfold the wing structure hidden in the body to form a large area of wing structure. After in-depth study of locust wings, researchers found that the reason why locust wings have high stability and high load-bearing capacity is that the wing structure is composed of longitudinal and transverse intersecting veins and wing membranes. The combination of rigid veins and flexible wing membranes forms a rigid-flexible coupling body, which plays a key role in improving mechanical properties. SUMMARY

[0006] In view of the above problems, the present application proposes a bionic variable stiffness folding and unfolding structure based on locust wings according to the characteristics of locust wings, which solves the problems commonly existing in existing space unfolding mechanisms.

[0007] This invention relates to a biomimetic variable stiffness folding and unfolding structure based on locust wings, which consists of a base and folding and unfolding surfaces.

[0008] The folding and unfolding array is located on both sides of the base and is fixed to the base symmetrically. The folding and unfolding array includes a biomimetic wing skeleton array, a flexible thin film array, a scissor-linked unfolding device, and a guide rail.

[0009] The biomimetic wing skeleton array consists of multiple biomimetic wing skeletons, with the front ends of each skeleton slidingly fitted onto arc-shaped guide tracks designed on the left and right sides of the front end of the base. A flexible thin film array is laid on the surface of the multiple biomimetic wing skeletons. A scissor-linked deployment device is installed between the opposite sides of adjacent biomimetic wing skeletons. The scissor-linked deployment device comprises a scissor unit consisting of four connecting rods hinged together, and preload springs installed between the opposite hinge axes. The other two opposite hinge axes of the scissor unit connect two adjacent biomimetic wing skeletons.

[0010] Thus, through the control of the drive mechanism, the bionic wing skeletons in the folding array can be synchronously unfolded or retracted along the guide track.

[0011] The advantages of this invention are:

[0012] 1. This invention is based on a biomimetic variable stiffness folding and unfolding structure of locust wings, which realizes the design of a spacecraft structure with an ultra-large unfolding-to-retract ratio. At the same time, it has a simple and reliable unfolding and retracting form and strong and stable anti-interference performance, ensuring the safety and reliability of the spacecraft in orbit.

[0013] 2. The present invention is based on a biomimetic variable stiffness folding and unfolding structure of locust wings, which has a spring mechanism that can provide pre-stored energy, can ensure the stability of the structure, and is suitable for purely passive unfolding.

[0014] 3. The present invention is based on a biomimetic variable stiffness folding and unfolding structure of locust wings. By pre-adjusting the preload value of the preloaded spring, the spring is still in working state after the overall structure is unfolded. This ensures the stability of the array during operation and forms a rigid-flexible coupled integrated structure, avoiding the problem of large response of a purely rigid structure under external disturbances.

[0015] 4. This invention is based on a biomimetic variable stiffness folding and unfolding structure of locust wings. The structure of each scissor-linked unfolding device is uniform, which facilitates modular design.

[0016] 5. The present invention is based on a biomimetic variable stiffness folding and unfolding structure of locust wings, which can adjust the length of each biomimetic wing skeleton, thereby achieving different array shapes and realizing diversified design of array structure.

[0017] 6. The present invention is based on a biomimetic variable stiffness folding and unfolding structure of locust wings. The use of preloaded springs allows the overall structure to unfold rapidly using stored elastic potential energy during the unfolding process, resulting in efficient unfolding. Attached Figure Description

[0018] Figure 1 This is a top view of the unfolded state of the biomimetic variable stiffness folding and unfolding structure based on locust wings of the present invention.

[0019] Figure 2 This is a three-dimensional view of the unfolded state of the biomimetic variable stiffness folding and unfolding structure based on locust wings of the present invention.

[0020] Figure 3 This is a schematic diagram of the scissor-linked deployment device in the biomimetic variable stiffness folding and unfolding structure based on locust wings of the present invention.

[0021] Figure 4 This is a schematic diagram of the folded state of the biomimetic variable stiffness folding and unfolding structure based on locust wings of the present invention.

[0022] In the picture:

[0023] 1-Base; 2-Folding array; 3-Drive mechanism

[0024] 201-Bionic wing skeleton array; 201a-Bionic wing skeleton; 202-Flexible thin film array.

[0025] 203-Scissor lift linkage deployment device; 203a-Preload spring; 203b-Scissor lift lever

[0026] 203c - First pivot; 203d - Second pivot; 203e - First intermediate pivot

[0027] 203f - Second intermediate pivot; 204 - Limiting rope; 205 - Guide rail

[0028] 301 - Ball screw; 302 - Drive link; 303 - Gear motor Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings.

[0030] This invention relates to a biomimetic variable stiffness folding and unfolding structure based on locust wings, consisting of a base 1 and two folding and unfolding surfaces 2. The base 1 simulates the main body of a locust; the two folding and unfolding surfaces 2 simulate the locust's wings, symmetrically arranged on the left and right sides of the base 1, as shown below. Figure 1 , Figure 2 As shown.

[0031] The aforementioned folding array 2 includes a biomimetic wing skeleton array 201, a flexible film array 202, a scissor-linked deployment device 203, a limiting rope 204, and a guide rail 205.

[0032] The guide rail 205 is used to connect the bionic wing skeleton array 201, ensuring the determinism and orderliness of the movement between each bionic wing skeleton 201a in the bionic wing skeleton array 201. The guide rail 205 is an arc-shaped rod structure, with its end fixed to the front end of the side of the base 1, and its inner arc facing the front of the base 1.

[0033] The biomimetic wing skeleton array 201 consists of multiple rectangular plate-structured biomimetic wing skeletons 201a of a certain length, used to simulate the rigid wing structure of a locust. Each biomimetic wing skeleton 201a has an arc-shaped hole at its front end, through which it fits onto a guide rail 205. The guide rail 205 restricts the movement trajectory of each biomimetic wing skeleton 201a, ensuring that each biomimetic wing skeleton moves only along the guide rail. The larger side of adjacent biomimetic wings is positioned opposite each other as a connecting surface, used to connect a scissor-linkage deployment device.

[0034] like Figure 3 As shown, the scissor-linked deployment device 203 realizes the synchronous deployment and retraction of the overall folding array 2. It is installed at the midpoint between adjacent bionic wing skeletons, ensuring that the included angles between adjacent bionic wing skeletons are equal. This allows the opposite sides of adjacent bionic wing skeletons 201a to fit together after all bionic wing skeletons 201a are fully retracted. The scissor-linked deployment device 203 includes a scissor unit and a preload spring 203a. The scissor unit consists of four scissor rods 203b, denoted as rods A to D. Rods A and B are of equal length, and their inner ends, along with the end of the preload spring 203a, are fitted onto the first rotating shaft 203c to form a rotating pair. Rods C and D are of equal length and shorter than the lengths of rods A and B. The inner ends of rods C and D, along with the front end of the preload spring 203a, are fitted onto the second rotating shaft 203d to form a rotating pair. The outer ends of rods A and C, together with the outer ends of rods B and D in an adjacent set of scissor-linked deployment devices 203, are sleeved on the first intermediate rotating shaft 203e to form a rotating pair; the outer ends of rods B and D, together with the outer ends of rods A and C in another adjacent set of scissor-linked deployment devices 203, are sleeved on the second intermediate rotating shaft 203f to form a rotating pair; the first intermediate rotating shaft 203d and the second intermediate rotating shaft 203f are respectively fixed on two adjacent bionic wing skeletons 201a, with the end of the preload spring 203b facing the end of the bionic wing skeleton 201a.

[0035] If the preload spring 203b can also be a tension spring, the end and front end of the tension spring 203b are respectively connected to the first rotating shaft 203c and the second rotating shaft 203d by steel wire ropes, and the tension spring can be preloaded to different degrees by adjusting the length of the steel wire ropes.

[0036] The flexible thin-film array 202 is laid on the top plane of the bionic wing array, with its outer circumferential edge laid and fixed along the longitudinal direction of the two outermost bionic wings 201a, and simultaneously connected and fixed to the ends of each bionic wing frame 201a; the shape of the flexible thin-film array 202 can be designed according to actual needs as follows: Figure 1 The number and length of each biomimetic wing skeleton 201a are designed according to the flexible thin film array 202, with the surface being rectangular or other shapes, so as to adapt to the shape of the flexible thin film array 202 and meet the structure after the array 2 is unfolded and retracted.

[0037] The aforementioned flexible thin-film array 202 is made of flexible material. When the biomimetic wing skeleton array 201 unfolds or retracts, the flexible thin-film array 202 can unfold or retract accordingly without affecting its function. When the biomimetic wing skeleton array 201 retracts, the flexible thin-film array 202 forms folds between two adjacent biomimetic thin-film skeletons 201a, avoiding motion interference between the skeletons. When the biomimetic wing skeleton array 201 retracts, the flexible thin-film array 202 unfolds into a plane.

[0038] The aforementioned folding and unfolding units are symmetrically placed on the left and right sides of the body 1. A bionic wing skeleton located on the outermost side is set along the front-back direction of the base 1 and fixed to the top edge of the side wall of the base 1. The front end is flush with the front end of the base 1 to facilitate connection to the drive mechanism 3. Here, the bionic wing skeleton 201a is designated as the innermost skeleton.

[0039] The drive mechanism 3 consists of two sets, one for driving the unfolding and the other for driving the unfolding and retracting of the folding array 2 on the left and right sides of the base 1. The two sets of drive mechanisms 3 are symmetrically arranged on the front of the top of the base 1, and are connected to the base 1 and the folding array 2 in the same way. The drive mechanism 3 includes a ball screw 301, a drive connecting rod 302, and a geared motor 303.

[0040] The ball screw 301 has a screw 302 arranged along the front-rear direction of the base 1, and both ends are supported by bearing seats. One end of the ball screw 301 is coaxially connected to the output shaft of the drive motor 303 and is driven to rotate by the geared motor 303. The screw nut sleeved on the ball screw 301 is connected to one end of the drive connecting rod 302 to form a rotating pair, and the axis of the rotating pair is perpendicular to the top surface of the base 1. Figure 4 As shown, the other end of the drive link 302 is connected to the front end of the top of another bionic wing skeleton 201a located on the outermost side to form a revolute joint. The axis of the revolute joint is perpendicular to the top surface of the base 1, making this skeleton the outermost skeleton. A variant four-bar linkage is formed by the ball screw 301, the base 1 (including the guide rail 205), the drive link 302 and the bionic wing skeleton 201a.

[0041] When the folding array 2 unfolds, the reduction motor 303 drives the ball screw 301 to rotate in the opposite direction, which in turn causes the screw nut to move linearly forward of the base 1, thereby driving the drive link 302 to perform rigid body motion, pushing the outermost skeleton forward along the guide rail 205 in the direction away from the base 1, and in turn driving each bionic wing skeleton 201a to move in an orderly manner along the guide rail 205 in the direction away from the base 1. The flexible thin film antenna unfolds accordingly, realizing the unfolding of the entire folding array 2. The rotation center of the unfolding process is determined by the size of the folding array.

[0042] During the aforementioned unfolding process, the braking torque of the drive motor 303 can be used to determine whether further unfolding is desired. If the unfolding continues after reaching the fully unfolded state, the drive motor 303 will engage the brake for locking protection. Alternatively, the operating stroke of the drive motor 303 corresponding to the unfolding motion stroke can be calculated, and the motor will stop and the brake will engage for locking protection when the drive motor 303 reaches that stroke. This achieves the control of the unfolding array 2 to reach its final position. When the fully unfolded state is reached, the flexible film array 202 is fully unfolded into a plane, reaching its maximum unfolded surface area, and the outermost skeleton reaches the front end of the guide rail 205, with the preload spring 203a in a stretched state. During this process, the length of the preload spring gradually decreases, effectively reducing the energy consumption of the drive device during unfolding. In applications where only unfolding is required and retraction is not, the energy storage of the preload spring 203a can be utilized, allowing for purely passive unfolding without the need for a drive device.

[0043] To prevent the outermost skeleton from detaching from the front end of the guide rail under external force when fully deployed, the present invention connects the opposite sides of adjacent biomimetic wing skeletons 201a with limiting ropes 204. The limiting ropes 204 are loose when the folding array 2 is not fully deployed, and become taut when fully deployed.

[0044] The folding and unfolding mechanism's retraction process is the reverse of the unfolding process. A geared motor drives the ball screw 301 to rotate, causing the screw nut to move linearly backwards from the base 1. This, in turn, drives the drive linkage 302 to perform rigid body motion, pulling the outermost frame backwards along the guide rail 205 towards the base 1. This, in turn, causes each bionic wing frame 201a to move in an orderly fashion along the guide rail 205 towards the base 1, achieving the folding and unfolding of the entire array 2. The folding and unfolding continues until the opposite sides of adjacent bionic wing frames 201a are in contact. At this point, the geared motor 303 stops, locking the mechanism in place. The array 2 is now fully folded. Figure 4 As shown.

[0045] In the fully unfolded state of the aforementioned folding array 2, the overall width of the biomimetic variable stiffness folding and unfolding structure of the present invention is equal to the sum of the width of the base 1 and the length of the biomimetic wing skeleton array 201 on both sides of the base 1 in the left and right directions when unfolded; in the fully folded state, the overall width is the sum of the width of the base 1 and the thickness between the left and right sides of all the biomimetic wing skeletons 201a; and the length of the biomimetic wing skeleton 201a is much greater than the thickness of the biomimetic wing skeleton 201a. Therefore, the biomimetic variable stiffness folding and unfolding structure of the present invention has the characteristic of a large folding-to-unfolding ratio.

[0046] During the unfolding of the aforementioned folding array 2, the pre-tension spring 203b designed in the outer scissor-linked unfolding device 203 exhibits overall variable stiffness characteristics. Although a single pre-tension spring 203b is a linear spring with a fixed stiffness, as the overall folding array 2 unfolds, the angle between each biomimetic wing skeleton 201a and the sidewall of the base 1 changes accordingly. The pre-tension spring 203b in the scissor-linked unfolding device 203 generates two component forces: one along the direction of the base 1 and the other perpendicular to the direction of the base 1. Through the force decomposition of the folding angle of the biomimetic wing skeleton 201a, the two component forces have a non-linear trigonometric function relationship, thereby achieving a change in stiffness. This variable stiffness characteristic helps the overall mechanism maintain stability during the unfolding process, effectively protecting the overall structure.

Claims

1. A biomimetic variable stiffness folding and unfolding structure based on locust wings, characterized in that: It consists of a matrix and unfolded array surfaces; The folding array is located on both sides of the base and is fixed symmetrically to the base. The folding array includes a biomimetic wing skeleton array, a flexible film array, a scissor-linked deployment device, and a guide rail; Among them, the bionic wing skeleton array is composed of multiple bionic wing skeletons, and the front ends of the multiple bionic wing skeletons are slidably sleeved on the arc-shaped guide tracks designed on the left and right sides of the front end of the base; the surface of the multiple bionic wing skeletons is covered with a flexible thin film array; and a scissor linkage deployment device is installed between the opposite sides of adjacent bionic wing skeletons. The scissor-linked deployment device consists of a scissor unit made up of four connecting rods hinged together and a preload spring installed between the relative hinge axes; the other two relative hinge axes of the scissor unit connect two adjacent bionic wing skeletons; thus, through the control of the drive mechanism, the bionic wing skeletons in the folding and unfolding array can be synchronously deployed or retracted along the guide track. The drive mechanism is installed on the top surface of the base and includes a ball screw, a drive link and a geared motor; wherein, the ball screw is arranged along the front-rear direction of the base and is supported by bearing seats at both ends; one end of the ball screw is coaxially connected to the output shaft of the geared motor; the end of the drive link is connected to the screw nut sleeved on the ball screw to form a rotating pair, and the front end of the drive link is used to connect with the front part of the outermost bionic wing skeleton to form a rotating pair; The aforementioned drive mechanism can be one or two sets. When there is one drive mechanism, it has two drive connecting rods. The ends of the two drive connecting rods are hinged to the corresponding positions on the left and right sides of the lead screw nut, and the front ends are respectively connected to the front of the bionic wing skeleton on the left and right sides of the base to form a rotating pair. When there are two drive mechanisms, they are symmetrically arranged on the left and right sides. Each of the two drive mechanisms has one drive connecting rod, and the front ends of the drive connecting rods are respectively connected to the front of the bionic wing skeleton on the left and right sides of the base to form a rotating pair.

2. The biomimetic variable stiffness folding and unfolding structure based on locust wings as described in claim 1, characterized in that: When the folding array is fully extended, the flexible film array is fully extended into a plane, reaching the maximum extended surface area, and the outermost skeleton reaches the front end of the guide rail, with the pre-tension spring in a stretched state; when the folding array is fully retracted, after each bionic wing skeleton is fully retracted, the opposite sides of adjacent bionic wing skeletons fit together.

3. The biomimetic variable stiffness folding and unfolding structure based on locust wings as described in claim 1, characterized in that: The adjacent scissor lift linkage deployment devices are positioned correspondingly, and the ends of the relative connecting rods are hinged to the same hinge axis on the bionic wing skeleton between them.

4. The biomimetic variable stiffness folding and unfolding structure based on locust wings as described in claim 1, characterized in that: The preload spring is replaced with a tension spring, and the end and front end of the tension spring are respectively connected to the two opposite hinge shafts of the scissor lift unit by steel wire ropes.

5. The biomimetic variable stiffness folding and unfolding structure based on locust wings as described in claim 1, characterized in that: The flexible thin film array is laid and fixed along the long direction of the two outermost bionic wing skeletons on the periphery, and is also connected and fixed to the ends of each bionic wing skeleton.

6. The biomimetic variable stiffness folding and unfolding structure based on locust wings as described in claim 1, characterized in that: The adjacent bionic wing skeletons are connected to each other by limiting ropes on opposite sides; the limiting ropes are loose when the folding array is fully unfolded, and become taut when it reaches the fully unfolded state.

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