Intelligent reconfigurable dynamic sun-shading system based on Kringing origami

Abstract

The invention relates to an intelligent reconfigurable dynamic sunshade system based on Kresling origami, which comprises a plurality of array structures, each array structure is composed of four unit cells composed of Kresling structures, and each unit cell comprises four panels, a panel with holes and a miniature fan; the four panels are sequentially connected to form a cavity, the panel with the holes is arranged at the top of the cavity, and the miniature fan is arranged on the upper portion of the panel with the holes. The panel is provided with creases, and the creases are made of a shape memory polymer material; and after the four unit cells in each array structure are opposite in pairs, the end points of the quadrangle on the top cover are connected to form transverse and vertical bidirectional symmetry, and the unit cells are intelligently folded and unfolded through temperature regulation and control, so that intelligent folding and unfolding of the array structure are realized. According to the intelligent reconfigurable dynamic sun-shading system based on Kresling paper folding, intelligent folding and unfolding are achieved through temperature control, and the problems that a traditional sun-shading structure is large in weight and poor in deformability are solved.

Description

Technical Field

[0001] The invention relates to an intelligent reconfigurable dynamic shading system based on Kresling origami. Background Art

[0002] Traditional building shading structures are generally made of rigid materials, with a single structure, heavy weight, large volume, and no axial elastic deformation capability. Traditional origami structures are usually driven by manual, motor or pneumatic actuators, resulting in bulky or large structures, which limits the scope of application. Summary of the invention

[0003] The present invention proposes an intelligent reconfigurable dynamic shading system based on Kresling origami. The structure includes intelligent folding and unfolding through temperature control, which solves the problems of heavy weight and weak deformation ability of traditional shading structures.

[0004] The technical solution of the present invention to solve the above problems is:

[0005] An intelligent reconfigurable dynamic shading system based on Kresling origami, which is special in that:

[0006] The invention comprises a plurality of array structures, wherein the array structure comprises four unit cells formed by a Kresling structure, each unit cell comprises four panels, a panel with holes and a micro fan; the four panels are sequentially connected to form a cavity, the panel with holes is arranged at the top of the cavity, and the micro fan is arranged at the upper part of the panel with holes; a fold is arranged on the panel, and the fold is made of a shape memory polymer material;

[0007] The four cells in each array structure are connected to each other at the ends of the quadrilateral on the rear top cover to form horizontal and vertical bidirectional symmetry. The cells are intelligently folded and unfolded by temperature control, thereby realizing intelligent folding and unfolding of the array structure.

[0008] Furthermore, the adjustable ventilation unit comprises a perforated panel and a micro fan, and the micro fan is arranged on the upper part of the perforated panel.

[0009] Furthermore, the perforated panel and the micro fan are coaxially arranged, and the perforated panel and the panel are seamlessly connected by high-temperature curing.

[0010] Furthermore, heating wires and sensors are pasted or embedded on both sides of the fold, and the temperature of the heating wires is controlled by a temperature controller, thereby changing the temperature of the fold to achieve intelligent control of the unit cell folding state. The sensors are used to monitor temperature, stress and light intensity.

[0011] Furthermore, the panel is made of engineering plastic ABS material; the adjustable ventilation unit is made of glass material; and the perforated panel is made of glass material.

[0012] Furthermore, the folded portion is made of shape memory polymer SMP.

[0013] Furthermore, the crease portion is made of shape memory polymer SMP and TPU.

[0014] Furthermore, the rotation speed of the micro fan is controllable.

[0015] Advantages of the present invention:

[0016] The Kresling origami cell structure of the present invention has a shape memory function, can achieve bistable state through temperature control, and the multi-stable origami structure can be folded and unfolded through temperature regulation. The design of the sensor and the electric heating plate at the crease can realize the control of the electric heating plate to change the temperature at the origami crease after setting a certain temperature change gradient, so that the origami structure can complete intelligent folding and unfolding after sensing the environment, and realize axial intelligent folding and unfolding and normal control. The upper and lower end surfaces can be compressed by a maximum of 90°, have a negative Poisson's ratio effect, can be self-locking when the temperature remains unchanged, have light weight, and strong deformation ability, and can realize the adjustment and control of the gap between the cells from square to diamond and then to closed. At the same time, the adjustable ventilation unit on the top surface can increase the air circulation speed through the rotation of the glass micro fan, increase the control range and control precision of the ventilation, and realize intelligent and artificially driven control of the ventilation of the building environment, so that the building environment can be simultaneously macro and micro regulated, and the requirements of different groups of people for different environments can be met, which has practical significance for the research and application of intelligent dynamic shading systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the unit cell structure of the present invention in a 0° unfolded state;

[0018] Figure 2 is a schematic diagram of a unit cell of the present invention in a 45° compressed state;

[0019] Figure 3 is a schematic diagram of a unit cell of the present invention in a state of being compressed by 90°;

[0020] Figure 4 It is a schematic diagram of the explosion of the unit cell of the present invention in a state of compression of 45°;

[0021] Figure 5 is a schematic diagram of an array structure composed of four unit cells of the present invention in a compressed 60° state;

[0022] Figure 6 It is a schematic diagram of an array structure composed of four unit cells from an expanded state to a compressed state of the present invention;

[0023] Figure 7It is a schematic diagram of the present invention wherein a plurality of array structures are assembled on a window in a compressed 45° state;

[0024] Figure 8 is the established Kresling superstructure rod model;

[0025] Fig. 9 It is a comparison between the experimental and theoretical results of Kresling model force and strain energy;

[0026] Fig.10 It is the simulation cloud map of the photothermal effect of the Kresling array structure (8:00, 10:00, 12:00, 14:00, 16:00, 18:00);

[0027] Fig.11 This is a simulation cloud map of the ventilation effect of the Kresling unit cell.

[0028] Among them: 1. unit cell structure, 1-1. fully unfolded state, 1-2. micro fan, 1-3. panel with holes, 1-4. sensor, 1-5. crease part, 1-6. heating wire, 2-1. 45° rotated folding state, 3-1. fully folded state, 3. unit cell, 4-1. axis, 5. array. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] Specific implementation method 1: Figures 1 to 7As shown, the present invention discloses an intelligent reconfigurable dynamic sunshade system based on Kresling origami, including a unit cell 1 with a quadrilateral and bistable upper and lower ends, the unit cell 1 is a Kresling origami structure, each unit cell 1 includes four panels and an adjustable ventilation unit; the four panels are connected in sequence to form a cavity, and the adjustable ventilation unit is arranged on the top of the cavity; folds 1-5 are provided on the panel, and the folds 1-5 are made of shape memory polymer material. After the four unit cells 1 in each array structure are opposite to each other, the end points of the quadrilateral on the adjustable ventilation unit are connected to form horizontal and vertical bidirectional symmetry, and the unit cell 1 is intelligently folded and unfolded by temperature control, so as to realize the intelligent folding and unfolding of the array structure.

[0031] Every four Kresling origami structure cells are combined and fixed into an array structure 5. The four Kresling origami structure cells of the array structure 5 are opposite to each other and the ends of the upper quadrilaterals are connected to form a cross-shaped array with horizontal and vertical bidirectional symmetry. The Kresling origami structure cells 1 and the array structure 5 can achieve intelligent folding and unfolding through temperature control. After a number of the array structures 5 are combined and arranged, they can be installed on the windows of a house to achieve the following: Figure 7 The temperature-controlled intelligent shading system with adjustable wind speed is shown.

[0032] Specific implementation method 2: Figure 1 , 2 As shown in Figures 3 and 6, this embodiment is a further explanation of the specific embodiment one. The four Kresling origami structure cells 1 are compressed under external load drive when they are in the expanded state and above the glass transition temperature of the material of the folds 1-5. Due to the structural characteristics, they can be rotated and folded at any angle and height, from the fully expanded state 1-1 to the 45° rotated folded state 2-1 and finally to the fully folded state 3-1, to produce folding deformation for shaping. After the shape shaping is completed, it is naturally cooled and fixed to form the field-shaped array structure 5. At the same time, the adjustable ventilation unit can be artificially controlled to start rotating the micro-fan design of the glass material on the top surface to increase the air flow speed and achieve the purpose of ventilation. When all the cells 1 of the field-shaped array structure 5 are heated to the same temperature at the same time, all the cells 1 return to the expanded state 1-1.

[0033] Specific implementation method three: Figure 1As shown, this embodiment is a further explanation of the specific embodiment 2. The four sides of the Kresling origami structure unit cell 1 use polyimide adhesive to stick or embed the heating wire 1-6 into the inner surface of the shape memory polymer on both sides of the fold 1-5 in the initial unfolded state, and at the same time, the sensor 1-4 is stuck to the inner surface of the shape memory polymer of the fold 1-5 in the unfolded state in the same way, so as to achieve temperature control of the heating wire 1-6 through a temperature controller. The sensor 1-4 is used to monitor the stress, deformation and other information of the building structure in real time, so as to achieve automatic control. The central control system receives data from each sensor and analyzes the state of the unit cell 1 in real time; the control system adjusts the heating power of the heating wire 1-6 according to the preset algorithm, thereby changing the temperature of the fold 1-5 to achieve intelligent control of the folding state of the unit cell.

[0034] Specific implementation method four: Figure 4 As shown, this embodiment is a further explanation of the specific embodiment 2, and the adjustable ventilation unit is composed of a perforated panel 1-3 and a micro fan 1-2, and the micro fan 1-2 is arranged on the upper part of the perforated panel 1-3. The centers of the perforated panel 1-3 and the micro fan 1-2 are both located on the axis 4-1, and are coaxially distributed in parallel up and down, and the perforated panel 1-3 is seamlessly connected with the surrounding panels 1-1. The folded portion 1-5 is made of shape memory polymer SMP material, or the folded portion 1-5 is made of shape memory polymer SMP and TPU material. The panel is made of engineering plastic ABS material; the adjustable ventilation unit 1-2 is made of glass material; the perforated panel 1-3 is made of glass material.

[0035] refer to Figures 1 to 4 As shown, the Kresling origami structure unit cell 1 is placed in a temperature box in an initial unfolded state and cured at 90°C for 1 hour, and then cured at 120°C for half an hour and then taken out, and heating wires 1-6 are attached to folds 1-5, and the Kresling origami structure unit cell 1 with heating wires 1-6 is placed in a temperature box at 100-120°C, and the specific temperature is determined according to the glass transition temperature Tg of the SMP material at the folds 1-5. After the material reaches the Tg temperature and softens after being placed for ten minutes, it is taken out of the temperature box, and the Kresling origami structure unit cell 1 is compressed by a tensile testing machine or external force, and reference is made to FIG. Figure 7 , so that the unit cell 1 is in a compressed state, the material returns to room temperature, and the unit cell achieves self-locking. At the same time, in this process, the adjustable ventilation unit can be manually controlled to work, and the effect of controlling the air circulation speed can be achieved by controlling the rotation of the micro fan 1-2. If you want it to stop in a certain state, stop heating and maintain the temperature when it reaches that state to achieve self-locking.

[0036] refer to Figures 5-6As shown, after four Kresling origami structure cells 1 are placed opposite to each other to form a cross-shaped array structure 5, the entire array structure 5 is simultaneously subjected to a high-temperature curing operation, and then an adhesive is used to attach heating wires 1-6 to the folds 1-5 of each cell 1. The heating wires 1-6 are electrically connected to a temperature controller through wires. The wires are arranged on the inner surface of each cell 1. After power is turned on, the temperature is controlled by the temperature controller, and each Kresling origami structure cell 1 is raised to the same temperature to soften the material. The array structure 5 is compressed by an external force. Figure 6 , so that the upper and lower end faces are displaced in the normal direction of the axis while folding axially, so that the four unit cells 1 in the combined structure 5 are changed from two-by-two relative to each other into a field-shaped structure, and the temperature controller is controlled to restore the material to room temperature to achieve self-locking. The temperature can also be controlled by the temperature controller to make it stop in the required state.

[0037] Modeling and analysis of the intelligent reconfigurable dynamic shading system based on Kresling origami of the present invention:

[0038] Establishment of theoretical model: Establish theoretical model using the principle of minimum potential energy. Figure 8 The geometric representation of the Kresling origami unit cell is shown, with triangles as its basic components. This study assumes that the length of the rod AB is denoted as a, while the lengths of the other sides are denoted by b and c, as follows:

[0039]

[0040] in, are the normalized radius and height.

[0041] Strain Energy:

[0042]

[0043] According to the stiffness equivalence principle, let

[0044] K shell =kK bar , (3)

[0045] k is the proportionality factor, and the strain energy of the shell model can be calculated as:

[0046]

[0047] Based on the idea of ​​minimum potential energy, the Kresling origami structure is currently in the minimum energy state of any intermediate state. Therefore, by maximizing the three variable parameters, the folding state of the structure can be accurately defined, thereby capturing the complex stress and deformation behavior caused by local folding.

[0048] Thermal-optical coupling analysis: A thermal-optical coupling mathematical model is established, taking into account the effects of changes in light intensity and temperature on the structure. The formula is as follows: The photothermal conversion efficiency, denoted as η, is an indicator that quantifies the effectiveness of converting light energy into thermal energy. It is defined as:

[0049]

[0050] Among them, Q heat =mc△T is the converted heat energy, I incident is the incident light energy, m is the mass of the material, c is the specific heat capacity, and ΔT is the change in temperature.

[0051] When light passes through matter, its intensity decreases, a phenomenon that can be quantified using the Beer-Lambert law:

[0052] I(x)=I0e -αx (6)

[0053] Where I(x) is the propagation distance x light intensity, I0 is the initial light intensity, and α is the absorption coefficient.

[0054] Once the material absorbs light energy, the heat conduction inside the material can be described by the heat conduction equation

[0055]

[0056] Where T is temperature, t is time, α T is the thermal diffusivity. For anisotropic materials, the thermal diffusivity α T is a tensor.

[0057] The energy balance of the light-absorbing species can be expressed as

[0058] I incident =I absorbed +I reflected +I transmitted (8)

[0059] Ideally, the energy I incident Completely converted into heat energy absorbed , that is, the energy and energy are close to zero. After the absorbed light energy is converted into heat energy, it can be expressed by the following relationship:

[0060] Q heat =I0(1-e -αx ). (9)

[0061] The temperature change of a substance is affected by blackbody radiation, the emission energy of which can be quantified using the Stefan-Boltzmann law P = σAT 4 (10)

[0062] Where P is the radiation power and σ is the Stefan-Boltzmann constant (5.67×10 -8 W·m -2 ·K -4 ), A is the surface area, and T is the absolute temperature.

[0063] Combining these formulas, we can get a general description of the light-to-heat conversion process. The light energy absorbed by the material I0(1-e -αx ) is converted into thermal energy mc△T, which affects the temperature change of the material through heat conduction and blackbody radiation. Combining these relationships, the total energy balance equation for photothermal conversion can be expressed as

[0064] I0(1-e -αx )=mc△T+σAT 4 (11)

[0065] Through the above formula, we can fully understand the physical process behind the light-heat coupling effect in the intelligent dynamic shading system. This understanding lays a theoretical foundation for future numerical simulation and experimental research.

[0066] Shading effect evaluation: By simulating sunlight at different times and angles, the shading effect of the Kresling origami structure in different folding states is evaluated. The experimental results show that the intelligent building structure can effectively adjust the indoor light and temperature under the conditions of light-heat coupling, and improve the comfort of living and working.

[0067] The samples were manufactured by 4D printing technology, and compression tests and numerical simulations were performed to verify the mechanical properties and thermal-optical coupling effects of the system. The experimental results show that the intelligent building structure can automatically fold and unfold under the conditions of thermal-optical coupling, significantly improving the lighting and ventilation conditions of the building environment, and improving the energy efficiency and comfort of the building.

[0068] Tests and Results

[0069] Compression test: The Kresling origami structure unit cell was placed in a temperature chamber in its initial unfolded state and subjected to compression tests at different temperatures. The compression force and deformation of the origami structure at different temperatures were measured experimentally. The results are as follows: Fig. 9 shown.

[0070] Light-shielding performance test: Kresling origami structures were installed on simulated windows to measure changes in indoor light intensity under sunlight at different times and angles. The experimental results show that Kresling origami structures can effectively adjust indoor light intensity, prevent glare, and improve living and office comfort in different folding states.

[0071] Thermal-optical coupling performance test: Under different lighting conditions, the surface temperature changes of the Kresling origami structure were measured. The results are as follows: Fig.10 The experimental results show that the Kresling origami structure can control the amount of sunlight incident on the structure by adjusting the folding angle, thereby adjusting the indoor temperature and reducing the energy consumption of air conditioning and heating.

[0072] Ventilation performance test: The ventilation effect of the Kresling origami structure was measured under different ventilation conditions. The results are as follows Fig.11 The experimental results show that the adjustable ventilation unit can effectively control the indoor and outdoor air circulation and improve the indoor air quality by changing the speed and angle of the fan.

[0073] Energy-saving effect evaluation: By monitoring the energy consumption of the building over a long period of time, the energy-saving effect of the Kresling origami structure is evaluated. The experimental results show that the intelligent building structure can significantly reduce the dependence on air conditioning and heating equipment through light-heat coupling and natural ventilation, reduce energy consumption, reduce carbon emissions, and has significant environmental benefits.

[0074] Structural stability test: The Kresling origami structure was subjected to long-term stability tests under different environmental conditions to evaluate its stability under conditions of high temperature, high humidity, wind load, etc. The experimental results show that the Kresling origami structure exhibits excellent stability and durability under a variety of environmental conditions.

[0075] In summary, the present invention proposes an intelligent reconfigurable dynamic shading system based on Kresling origami, including a single-cell Kresling origami structure with quadrilateral upper and lower ends and bistable state, wherein the crease part of the single-cell structure is made of shape memory polymer (SMP) and polyurethane (TPU) materials, and the remaining panel parts are made of engineering plastic (ABS) material. Since the shape memory polymer used in 4D printing is a network polymer with a transition temperature, the intelligent origami can achieve the purpose of sequential self-folding and self-locking. In view of the panel shape and internal structure problems of origami, a quadrilateral module is used, which can change its opening percentage according to the rotational displacement of the upper and lower ends of the shrinking prism. By changing its height at the same time, the model allows a gradual conversion between 0° and 90°. A rotation angle of 0° will result in the maximum opening percentage and maximum height of the module, while a 90° rotation will reduce the opening percentage and height of the module to the minimum value. A sensor is provided at the fold of the origami, and electric heating plates are provided on both sides of the fold. The sensor controls the electric heating plates by sensing the ambient temperature. When the sensor receives that the ambient temperature is too high, the electric heating plates are controlled to heat the fold, thereby changing the temperature around the origami structure, so as to achieve the purpose of controlling the origami structure to design hinges with SMPs of different transition temperatures, and realizing the sequential self-folding and self-locking structural folding of the intelligent origami, so that the Kresling origami structure automatically unfolds to increase the ventilation area. In this process, the adjustable ventilation unit can be manually controlled to work, so that the micro fan design of the top glass material starts to rotate, and the air flow speed is increased to achieve the purpose of ventilation. At the same time, every four origami unit cell structures are connected to each other through the endpoints of the upper quadrilateral, and the upper and lower end faces are displaced in the normal direction of the axis while folding in the axial direction, so that the four unit cells in the combined structure are changed from two to two to a field-shaped structure.

[0076] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0077] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An intelligent reconfigurable dynamic shading system based on Kresling origami, characterized by: The invention comprises a plurality of array structures, wherein the array structure comprises four single cells (1) formed by a Kresling structure, each single cell (1) comprises four panels and an adjustable ventilation unit; the four panels are sequentially connected to form a cavity, and the adjustable ventilation unit is arranged on the top of the cavity; folds (1-5) are arranged on the panels, and the folds (1-5) are made of shape memory polymer material; The four cells (1) in each array structure are connected to each other at the end points of the quadrilateral on the rear top cover (1-3) to form horizontal and vertical bidirectional symmetry. The cells (1) are intelligently folded and unfolded through temperature control, thereby realizing intelligent folding and unfolding of the array structure.

2. The intelligent reconfigurable dynamic shading system based on Kresling origami according to claim 2 is characterized by: The adjustable ventilation unit comprises a panel with holes (1-3) and a micro fan (1-2), wherein the micro fan (1-2) is arranged on the upper part of the panel with holes (1-3).

3. The intelligent reconfigurable dynamic shading system based on Kresling origami according to claim 2 is characterized by: The perforated panel (1-3) and the micro fan (1-2) are coaxially arranged via an axis (4-1), and the perforated panel (1-3) and the panel are seamlessly connected via high-temperature curing.

4. According to claim 3, the intelligent reconfigurable dynamic shading system based on Kresling origami is characterized in that: Heating wires (1-6) and sensors (1-4) are pasted or embedded on both sides of the fold (1-5), and the temperature of the heating wires (1-6) is controlled by a temperature controller, thereby changing the temperature of the fold (1-5) to achieve intelligent control of the folding state of the unit cell (1). The sensors (1-4) are used to monitor temperature, stress and light intensity.

5. The intelligent reconfigurable dynamic shading system based on Kresling origami according to claim 4 is characterized in that: The panel is made of engineering plastic ABS material; the adjustable ventilation unit (1-2) is made of glass material; and the panel with holes (1-3) is made of glass material.

6. The intelligent reconfigurable dynamic shading system based on Kresling origami according to any one of claims 1 to 5, characterized in that: The folded portion (1-5) is made of shape memory polymer SMP material.

7. An intelligent reconfigurable dynamic shading system based on Kresling origami according to any one of claims 1 to 5, characterized in that: The folded portion (1-5) is made of shape memory polymer SMP and TPU.

8. The intelligent reconfigurable dynamic shading system based on Kresling origami according to any one of claims 1 to 5, characterized in that: The rotation speed of the micro fan (1-2) is controllable.

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