4D printing variable poisson ratio structure for driving intelligent wing and programmable deformation control method

Abstract

The invention discloses a 4D printing variable poisson ratio structure for driving an intelligent wing and a programmable deformation control method. The 4D printing variable Poisson's ratio structure comprises two clamping plates and a variable Poisson's ratio structural body arranged between the two clamping plates. The variable Poisson's ratio structural body is made of a shape memory material through a 4D printing forming technology, and different mechanical properties and deformability can be achieved through different geometric structure designs of the variable Poisson's ratio structural body. According to the programmable deformation control method, according to the deformation requirement of the deformation wing, the geometrical configuration, the unit space distribution and the combination mode of the units in the variable Poisson's ratio structural body are selected so as to accurately control and customize the deformation behavior of the wing, and meanwhile programmable active drive deformation after set shaping can be achieved under the electric heating excitation condition. Therefore, the intelligent wing can be driven to continuously deform in the space, the dynamic adjustment of the shape of the wing is realized, and the adaptability of the aircraft in different flight environments and tasks is improved.

Description

Technical Field

[0001] The present invention belongs to the field of advanced manufacturing technology, and specifically relates to a 4D-printed variable Poisson's ratio structure and a programmable deformation control method for driving intelligent wings. Background Art

[0002] Smart drones can adapt their wing shape in real time to achieve optimal aerodynamic performance based on actual flight conditions, improving flight performance and efficiency while meeting the requirements of multi-mission and complex flight conditions. The main challenge in developing a successful smart wing is designing a deformable structure and material that is both easily deformable in-plane and rigid enough to withstand significant out-of-plane aerodynamic loads.

[0003] Various planar honeycomb structures have been proposed for intelligent morphing wings, including multistable honeycombs, star-shaped honeycombs, curved honeycombs, and various variable Poisson's ratio structures. Variable Poisson's ratio materials, for example, are capable of expanding, contracting, or remaining constant longitudinally while simultaneously stretching transversely. The high designability of these deformable structures can meet the various mechanical and functional requirements of intelligent morphing wings in practical applications, enabling controlled deformation in dimensions such as span and chord length, and effectively improving the aerodynamic performance of aircraft.

[0004] Most currently proposed morphing wing structures require additional actuators, such as pneumatic muscle fibers, drive motors, or metal actuators, to provide powerful power. This requires efficient integration of these actuators within a limited space, at the expense of increased structural complexity and weight. Furthermore, the wing's degree of freedom of deformation is limited due to the constraints of the morphing structure. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention aims to solve the technical problems that the existing deformable structure requires additional integrated actuators, which increases the structural complexity and weight of the drone and has a low degree of design freedom. By providing a 4D-printed variable Poisson's ratio structure and a programmable deformation control method for driving intelligent wings, the present invention aims to solve the technical problems that the existing deformable structure requires additional integrated actuators, which increases the structural complexity and weight of the drone and has a low degree of design freedom.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A 4D-printed variable Poisson's ratio structure for driving an intelligent wing, comprising two plywood plates and a variable Poisson's ratio structure disposed between the two plywood plates;

[0008] The variable Poisson's ratio structure is made of shape memory material using 4D printing technology and includes several corrugated polygonal ring units distributed in a rectangular array;

[0009] Each corrugated polygonal ring unit includes at least three corrugated walls, each corrugated wall is arranged in a Z-shape, and each corrugated wall is connected end to end to form the corrugated polygonal ring unit;

[0010] In the variable Poisson's ratio structure, adjacent corrugated polygonal ring units are connected into one body via a corrugated wall.

[0011] Preferably, a node is formed between two adjacent corrugated walls, and the two corrugated walls on both sides of each node are connected to the corresponding node in a chiral connection manner.

[0012] Preferably, the corrugated wall comprises a three-section structure sequentially connected into one body, corresponding to the first to third corrugated wall parts, wherein:

[0013] The coordinates (x, y) of any point on the first corrugated wall satisfy:

[0014]

[0015] The coordinates (x, y) of any point on the second corrugated wall satisfy:

[0016]

[0017] The coordinates (x, y) of any point on the third corrugated wall satisfy:

[0018]

[0019] Preferably, in the variable Poisson's ratio structure, the polygon type of each corrugated polygonal ring unit is a triangle, a quadrilateral and / or a hexagon.

[0020] Preferably, in the variable Poisson's ratio structure, the polygon type selection of each corrugated polygonal annular unit, the parameter design of the corrugated wall, and the determination of the arrangement of each corrugated polygonal annular unit are realized based on programmable control of mechanical properties and deformation behavior; the parameter design of the corrugated wall includes the shape, width, length and thickness design of the corrugated wall.

[0021] Another technical object of the present invention is to provide an intelligent deformable drone, comprising a fuselage and two wings symmetrically arranged on either side of the fuselage, wherein the wings are intelligent deformable wings and comprise a connecting rod and intelligent deformable ribs uniformly arranged along the length of the connecting rod;

[0022] The intelligent deformable rib comprises a leading edge portion, a trailing edge portion, and an active deformation driving portion arranged between the leading edge portion and the trailing edge portion;

[0023] The active deformation driving part is the above-mentioned 4D printed variable Poisson's ratio structure.

[0024] Another technical object of the present invention is to provide a programmable deformation control method for the above-mentioned intelligent deformable drone, comprising the following steps:

[0025] Step 1: Based on the overall deformation requirements of the intelligent UAV and the programmable control of the mechanical properties and deformation behavior of the variable Poisson's ratio structure, the 4D printed variable Poisson's ratio structure in each intelligent deformable rib is designed;

[0026] The design of the 4D-printed variable Poisson's ratio structure in each intelligent deformable rib includes:

[0027] a. Select the polygon type of the corrugated polygonal ring unit;

[0028] b. Design the shape, width, length and thickness of the corrugated wall of the corrugated polygonal ring unit;

[0029] c. Design the arrangement pattern of each corrugated polygonal ring unit;

[0030] Step 2: Based on the design results of Step 1, the intelligent deformable wing rib is integrally formed by 4D printing technology; wherein: the 4D printed variable Poisson's ratio structure is made of shape memory material;

[0031] Step 3: Using an electrothermal method to excite the variable Poisson's ratio structure, the ribs of the intelligent deformable wing are actively driven to continuously deform in space according to the predetermined shape;

[0032] Step 4: According to the overall deformation requirements of the intelligent UAV, the ribs of each intelligent deformable wing are assembled to the fuselage, and the overall programmable deformation control of the intelligent UAV is driven by the coordinated control of the deformation behaviors of multiple ribs.

[0033] Preferably, in step 4, the electrothermal method is specifically as follows: a DC power supply is loaded on the 4D printed variable Poisson's ratio structure, so that Joule heat is generated inside the 4D printed variable Poisson's ratio structure, thereby realizing the conversion of electrical energy into thermal energy; and the temperature of the 4D printed variable Poisson's ratio structure is controlled by controlling the current intensity of the DC power supply, thereby realizing programmable active drive deformation control of the 4D printed variable Poisson's ratio structure after a predetermined shape is given based on the current intensity.

[0034] Preferably, the mechanical properties of the variable Poisson's ratio structure include Poisson's ratio, elastic modulus and tensile strength.

[0035] Compared with the prior art, the advantages of the present invention are:

[0036] 1. The present invention discloses a 4D-printed variable Poisson's ratio structure. The variable Poisson's ratio structure comprises corrugated polygonal ring units arranged in a predetermined rectangular array. Each of the corrugated polygonal ring units is formed by connecting three or more corrugated walls end-to-end, each arranged in a Z-shaped pattern. Furthermore, the variable Poisson's ratio structure is fabricated using shape memory material using 4D printing technology. Thus, the 4D-printed variable Poisson's ratio structure of the present invention can be deformed by temperature control (when heated to the phase transition temperature of the 4D-printed variable Poisson's ratio structure, the 4D-printed variable Poisson's ratio structure deforms due to the shape memory effect of its material, causing the entire intelligent deformable rib to deform accordingly. When the 4D-printed variable Poisson's ratio structure cools, it gradually returns to its initial shape, driving the entire intelligent deformable rib to return to its initial state). In addition, by adjusting the polygon type of the corrugated polygonal annular units, the parameters of the corrugated walls, and the arrangement, the mechanical properties of the 4D-printed variable Poisson's ratio structure can be regulated, thereby adjusting the deformation behavior of the 4D-printed variable Poisson's ratio structure. This provides a basis for the design of variable Poisson's ratio structures using programming methods. 2. The 4D-printed variable Poisson's ratio structure of the present invention is realized based on programmable control of mechanical properties and deformation behavior. By controlling the temperature of the 4D-printed variable Poisson's ratio structure, the 4D-printed variable Poisson's ratio structure can be actively driven to deform according to the predetermined shape based on the programmable control.

[0037] 3. The temperature control of the 4D printed variable Poisson's ratio structure described in the present invention is achieved by electrothermal means, that is, the present invention can control the temperature of the 4D printed variable Poisson's ratio structure by controlling the current intensity of the 4D printed variable Poisson's ratio structure, thereby realizing programmable active drive deformation control after a predetermined shaping based on the current intensity.

[0038] 4. The present invention applies the above-mentioned 4D-printed variable Poisson's ratio structure to the mid-section of the wing rib of an intelligent deformable drone. Therefore, the deformation of the wing rib can be achieved by controlling the deformation of the above-mentioned 4D-printed variable Poisson's ratio structure, thereby achieving continuous deformation of the wing of the intelligent deformable drone according to a predetermined shape. Specifically, the mid-section of the wing rib of the present invention adopts a 4D-printed variable Poisson's ratio structure, which is composed of multiple corrugated polygonal annular units. Adjacent corrugated polygonal annular units can be of the same type or different types. By designing the structure of the corrugated polygonal annular units in the deformation drive portion of the mid-section of a single or multiple wing rib structures, different mechanical properties can be obtained, and programmable deformation control of a single or multiple wing rib structures can be achieved. The variable Poisson's ratio structure is formed from a shape memory material formed by additive manufacturing. Under electrothermal excitation, it can achieve programmable active drive deformation after a predetermined shape, realizing programmable deformation control based on current intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1The figure is a schematic structural diagram of the intelligent transformable UAV of the present invention.

[0040] Figure 2 for Figure 1 Schematic diagram of the structure of the intelligent deformable wing.

[0041] Figure 3 for Figure 2 Schematic diagram of the structure of the intelligent deformable rib.

[0042] Figure 4 for Figure 3 Schematic diagram of the structure of the medium-corrugated polygonal ring unit.

[0043] Figure 5 Schematic diagrams of various variable Poisson's ratio structures in the active deformation drive portion of the present invention. In the figures: (a) shows a variable Poisson's ratio structure as a corrugated hexagonal array; (b) shows a variable Poisson's ratio structure as a corrugated triangular array; (c) shows a variable Poisson's ratio structure as a corrugated quadrilateral array; (d) shows a variable Poisson's ratio structure as a hybrid array.

[0044] Figure 6 A comparison diagram of force-displacement curves of various variable Poisson's ratio structures in the active deformation driving part of the present invention;

[0045] Figure 7 A comparison chart of the Poisson's ratios of various variable Poisson's ratio structures in the active deformation drive part of the present invention.

[0046] Figure 8 Schematic diagram of the flow of the programmable deformation control method of the present invention.

[0047] In the figure: 1. Wing rib structure; 11. Leading edge part; 12. Mid-section active deformation drive part; 13. Trailing edge part; 14. Connecting rod; 2. Intelligent deformable wing; 3. Fuselage; 4. Nose; 5. Tail. Specific implementation methods

[0048] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes and improvements made on the basis of the technical solution of this application fall within the scope of protection of the present invention.

[0049] like Figures 1 to 7 As shown, this embodiment provides a 4D-printed variable Poisson's ratio structure for driving an intelligent wing. By designing the structure of the corrugated polygonal ring unit in the deformation driving portion of the middle section of a single or multiple rib structure 1, different mechanical properties can be obtained, enabling programmable deformation control of the single or multiple rib structures 1. The variable Poisson's ratio structure is located in the middle section of the rib structure 1 of the wing of the intelligent deformable drone.

[0050] The overall structure of the intelligent deformable drone is as follows: Figure 1 As shown, it includes a nose 4, a fuselage 3, a tail 5, an intelligent deformable wing 2 and other parts. The intelligent deformable wing 2 is the key part that drives the UAV to be deformable.

[0051] The main internal structure of the intelligent deformable wing 2 is as follows Figure 2 As shown, it includes a plurality of intelligent deformable ribs and connecting rods 14. The connecting rods 14 connect the intelligent deformable ribs, and the intelligent deformable ribs drive the deformation.

[0052] like Figure 3 As shown, the intelligent deformable rib comprises a leading edge portion 11, an active deformable drive portion 12, and a trailing edge portion 13. The active deformable drive portion 12 is arranged between the leading and trailing edge portions 11, 13. The leading and trailing edge portions 11, 13 act as driven structures, driven by the active deformation of the active deformable drive portion 12. These components are integrally formed through additive manufacturing. The midsection active deformable drive portion 12 consists of a variable Poisson's ratio structure and upper and lower clamping plates.

[0053] The 4D printed variable Poisson's ratio structure of the present invention is a mesh structure formed by periodically arraying corrugated polygonal ring units, including two plywood and a variable Poisson's ratio structure arranged between the two plywoods; the variable Poisson's ratio structure is made of shape memory material through 4D printing technology, and includes a plurality of corrugated polygonal ring units distributed in a rectangular array. Figure 4 、 5 As shown, the polygonal types of the corrugated polygonal annular unit include hexagons, quadrilaterals and / or triangles; each corrugated polygonal annular unit includes at least three corrugated walls, each corrugated wall is arranged in a Z-shape, and each corrugated wall is connected end to end to form the corrugated polygonal annular unit; in the variable Poisson's ratio structure, adjacent corrugated polygonal annular units are connected into one body through a corrugated wall (i.e., adjacent corrugated polygonal annular units share the same corrugated wall). Specifically, a node is formed between two adjacent corrugated walls, and the two corrugated walls on both sides of each node are connected to the corresponding node in a chiral connection manner.

[0054] The programmable configuration of the corrugated polygonal annular units in the rib structure 1 enables continuous adjustment of the overall wing morphology. The rib structure 1 comprises a leading edge portion 11, an active deformation drive portion 12, and a trailing edge portion 13. The leading and trailing edge portions 11 and 13 are driven structures, relying on the active deformation of the active deformation drive portion 12 to drive the deformation of the driven portions. The entire rib structure 1 is formed in one piece using additive manufacturing to ensure structural continuity and coordination. The active deformation drive portion 12 is composed of a variable Poisson's ratio structure. By optimizing the geometric configuration, spatial distribution, and combination of the units, different mechanical properties can be achieved, allowing precise control and customization of the deformation behavior. Furthermore, the 4D-printed variable Poisson's ratio structure is made of shape memory material and can achieve programmable active deformation after a predetermined shape under electrothermal stimulation. The 4D-printed variable Poisson's ratio structure and programmable deformation control method of the present invention can drive the continuous deformation of the intelligent wing in space, achieving dynamic adjustment of the wing shape and improving the adaptability of the aircraft in different flight environments and missions.

[0055] The corrugated wall in the corrugated polygonal annular unit of the present invention can be defined by a composite function, which is defined in millimeters and includes a three-segment structure connected in sequence into one body, corresponding to the first to third corrugated wall segments, and is defined by the following function:

[0056]

[0057] In the above formula, i represents the first corrugated wall segment; ii represents the second corrugated wall segment; iii represents the third corrugated wall segment.

[0058] The width of the corrugated wall is 3 mm, the length is 1.5π mm, and the thickness is 3 mm.

[0059] The corrugated polygonal ring unit of the present invention is controlled by parameters, including selecting the polygon type of the corrugated polygonal ring unit and designing the shape, width, length and thickness of the composite function corrugated wall to control the mechanical properties of the corrugated polygonal ring unit. Adjacent corrugated polygonal ring units can be of the same type or different types, and a corrugated hexagonal array can be obtained based on different combinations [see attached Figure 5 (a), formed by the arrangement of corrugated hexagonal ring units in a rectangular array], corrugated quadrilateral array [refer to the attached Figure 5 (c), formed by the arrangement of corrugated quadrilateral ring units in a rectangular array], corrugated triangle array [refer to the attached Figure 5 (b), formed by the arrangement of corrugated triangular ring units in a rectangular array] and various hybrid arrays [see attached Figure 5(d) is formed by a mixed arrangement of corrugated hexagonal annular units and corrugated triangular annular units, and the corrugated hexagonal annular units are arranged in a rectangular array, and the corrugated triangular annular units are also arranged in a corrugated triangular annular unit; the corrugated hexagonal annular units and the corrugated triangular annular units at adjacent positions are connected into one through the corrugated wall, that is, the two share the same corrugated wall], to control the mechanical properties of the variable Poisson's ratio structure.

[0060] In a specific embodiment, shape memory materials are used to form the variable Poisson's ratio structure proposed in the present invention through additive manufacturing technology. Different types of variable Poisson's ratio structures are used as models for uniaxial tensile finite element simulations. The force-displacement curves and Poisson's ratio changes are shown in Figure 2. Figure 6 、 Figure 7 As shown, the results show that through the design and layout of the corrugated polygonal ring unit structure, different overall mechanical properties of the variable Poisson's ratio structure and controllable Poisson's ratio changes can be achieved.

[0061] like Figure 8 As shown, the programmable deformation control method based on a 4D-printed variable Poisson's ratio structure proposed in this invention is divided into three stages: the design and formation of a single intelligent wing rib structure 1, active deformation control driven by electrothermal excitation, and coordinated control of multiple intelligent wing rib structures 1. The first two stages only involve a single rib structure 1. The third stage can design and arrange multiple rib structures 1 based on the deformation requirements of the entire intelligent drone using methods similar to the first two stages. This method specifically includes the following steps:

[0062] Step 1: First, the structural parameters of the corrugated polygonal ring unit in the variable Poisson's ratio structure are designed. This involves selecting the polygon type of the corrugated polygonal ring unit and designing parameters such as the shape, width, length, and thickness of the composite function-based corrugated wall. Furthermore, the corrugated wall shape based on the composite function can be customized, including parameters such as the function type, amplitude, and length, width, and thickness of the corrugated wall. Through structural design, multiple types of corrugated polygonal ring units, such as A, B, C, etc., can be obtained, serving as the basis for the programmable design of variable Poisson's ratio structures.

[0063] Step 2: Array the designed corrugated polygonal annular units. The array can be in the form of a single unit or a composite unit. Different array forms have different mechanical properties. The variable Poisson's ratio structural mechanical properties and deformation behavior of a single intelligent wing rib structure 1 can be programmably controlled according to actual needs.

[0064] Step 3: Using shape memory materials, a variable Poisson's ratio structure is formed through additive manufacturing. When the temperature rises above the phase transition temperature, the material deforms due to the shape memory effect, causing the entire rib structure 1 to deform accordingly. As the variable Poisson's ratio structure cools, it gradually returns to its initial shape, driving the entire rib structure 1 back to its initial state. Deformation can be driven by electrothermal excitation. A DC power supply is applied to the variable Poisson's ratio structure, generating Joule heating (i.e., resistive heating) within the structure, converting electrical energy into thermal energy. By controlling the current intensity, the temperature of the structure is controlled, achieving programmable active drive deformation control based on a given current intensity.

[0065] Step 4: According to the deformation requirements of the entire intelligent UAV, the variable Poisson's ratio structures in the multiple wing ribs are designed and arranged to achieve coordinated control of the deformation behaviors of the multiple wing rib structures 1, thereby achieving continuous deformation of the wing in space.

Claims

1. A 4D-printed variable Poisson's ratio structure for driving an intelligent wing, characterized by: The invention comprises two plywood plates and a variable Poisson's ratio structure arranged between the two plywood plates; The variable Poisson's ratio structure is made of shape memory material through 4D printing technology, and includes several corrugated polygonal ring units distributed in a rectangular array; Each corrugated polygonal ring unit includes at least three corrugated walls, each corrugated wall is arranged in a Z-shape, and each corrugated wall is connected end to end to form the corrugated polygonal ring unit; In the variable Poisson's ratio structure, adjacent corrugated polygonal ring units are connected into one body via a corrugated wall.

2. The 4D printed variable Poisson's ratio structure for driving an intelligent wing according to claim 1, characterized in that: A node is formed between two adjacent corrugated walls, and the two corrugated walls on both sides of each node are connected to the corresponding node in a chiral connection manner.

3. The 4D printed variable Poisson's ratio structure for driving an intelligent wing according to claim 1, characterized in that: The corrugated wall comprises a three-section structure sequentially connected into one body, corresponding to the first to third corrugated wall parts, wherein: The coordinates (x, y) of any point on the first corrugated wall satisfy: The coordinates (x, y) of any point on the second corrugated wall satisfy: The coordinates (x, y) of any point on the third corrugated wall satisfy:

4. The 4D printed variable Poisson's ratio structure for driving an intelligent wing according to claim 3, characterized in that: In the variable Poisson's ratio structure, the polygon type of each corrugated polygonal ring unit is a triangle, a quadrilateral and / or a hexagon.

5. The 4D printed variable Poisson's ratio structure for driving an intelligent wing according to claim 4, characterized in that: In the variable Poisson's ratio structure, different mechanical properties of the 4D printed variable Poisson's ratio structure can be achieved based on the selection of polygon type of each corrugated polygonal annular unit, the parameter design of the corrugated wall, and the selection of the arrangement method of each corrugated polygonal annular unit; the mechanical properties of the variable Poisson's ratio structure include Poisson's ratio, elastic modulus, tensile strength, etc.; the parameter design of the corrugated wall includes the shape, width, length and thickness design of the corrugated wall.

6. An intelligent deformable drone, comprising a fuselage and two wings symmetrically arranged on both sides of the fuselage, characterized in that: The wing is an intelligent deformable wing, comprising a connecting rod and intelligent deformable ribs evenly arranged along the length of the connecting rod; The intelligent deformable rib comprises a leading edge portion, a trailing edge portion, and an active deformation driving portion arranged between the leading edge portion and the trailing edge portion; The active deformation driving part is the 4D printed variable Poisson's ratio structure as described in any one of claims 1 to 5.

7. A programmable deformation control method for an intelligent deformable UAV according to claim 6, characterized in that: The steps include: Step 1: Based on the mechanical properties of variable Poisson's ratio structures under different structural designs, the 4D-printed variable Poisson's ratio structures in each intelligent deformable rib are designed to achieve programmable control of the mechanical properties and deformation behavior of each deformable rib; The design of the 4D-printed variable Poisson's ratio structure in each intelligent deformable rib includes: a. Select the polygon type of the corrugated polygonal ring unit; b. Design the shape, width, length and thickness of the corrugated wall of the corrugated polygonal ring unit; c. Design the arrangement pattern of each corrugated polygonal ring unit; Step 2: Based on the design results of Step 1, the intelligent deformable wing rib is integrally formed by 4D printing technology; wherein: the 4D printed variable Poisson's ratio structure is made of shape memory material; Step 3: Using an electrothermal method to excite the variable Poisson's ratio structure, the ribs of the intelligent deformable wing are actively driven to continuously deform in space according to the predetermined shape; Step 4: According to the overall deformation requirements of the intelligent UAV, the ribs of each intelligent deformable wing are assembled to the fuselage, and the overall programmable deformation control of the intelligent UAV is driven by the coordinated control of the deformation behaviors of multiple ribs.

8. The programmable deformation control method of the intelligent deformable UAV according to claim 7, characterized in that: In step three, the electrothermal method is specifically as follows: a DC power supply is loaded on the 4D printed variable Poisson's ratio structure, so that Joule heat is generated inside the 4D printed variable Poisson's ratio structure, realizing the conversion of electrical energy into thermal energy; and the temperature of the 4D printed variable Poisson's ratio structure is controlled by controlling the current intensity of the DC power supply, thereby realizing programmable active drive deformation control of the 4D printed variable Poisson's ratio structure after a predetermined shape is given based on the current intensity.

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