Active deformation folding and unfolding structure driven by artificial muscle fiber, and preparation method and application of active deformation folding and unfolding structure

Abstract

The invention discloses an active deformation folding and unfolding structure driven by artificial muscle fibers as well as a preparation method and application of the active deformation folding and unfolding structure. The active deformation folding and unfolding structure comprises artificial muscle fibers, a first folding and unfolding part and a second folding and unfolding part; the folding and unfolding part is rotationally connected at the connecting shaft; a matching part is arranged on the folding and unfolding part; the artificial muscle fiber is at least matched with the first matching position and the second matching position in an abutting mode, the middle section is located between the first matching position and the second matching position, the first section extends from the first matching position to the connecting shaft, and the second section extends from the second matching position to the connecting shaft. According to the active deformation folding and unfolding structure provided by the invention, the artificial muscle fibers which are arranged in a triangular subsection mode are combined with the connecting points which abut against and are matched with the two folding and unfolding parts, complete folding and unfolding of the two folding and unfolding parts can be achieved with the contraction amount lower than 50%, the original state can be recovered when the artificial muscle fibers stretch, and the active deformation folding and unfolding structure has the advantage of being high in degree of freedom; the method is suitable for multiple scenes.

Description

Technical Field

[0001] The present invention relates to the field of material science and technology, and in particular to an active deformation folding and unfolding structure driven by artificial muscle fibers, and a manufacturing method and application thereof. Background Art

[0002] Whether it is a large animal or a small animal, movement depends on muscles, so the study of artificial muscles to realize the function of muscles has great application prospects. In recent years, the development of artificial muscles has attracted widespread attention. Inspired by nature, people have created a series of artificial muscles.

[0003] From the perspective of application fields, foldable structures are everywhere. In the field of architecture, it brings more creativity and flexibility to architectural design, such as foldable building roofs and movable stages, which can change the spatial form according to different usage requirements. In the field of aerospace, foldable structures are even more indispensable. For example, the deployable solar panels and antennas of satellites are compactly folded during launch and unfolded after entering space, effectively saving launch space and realizing specific functions. In addition, in the fields of robots, medical equipment, emergency rescue, etc., foldable structures also play an important role. For example, deformable rescue robots can shuttle in complex environments, providing convenience for rescue work.

[0004] However, the application of artificial muscles in foldable structures has encountered various problems. When Polina Anikeev et al. used artificial muscles for specific demonstrations, they only fixed the fibers between the upper and lower arms of the model to make them contract simply and cause the arms to bend. Because the center of gravity of the fibers migrated during the contraction process, they could not achieve linear contraction and could not cause complete folding. Yang et al. combined artificial muscle fibers with foldable structures to achieve the initial application of artificial muscle fibers in three-dimensional space, but the artificial muscles they used were nickel-titanium alloy wires, which had disadvantages such as metal fatigue and slow recovery speed, limiting their application in foldable structures. Leng et al. combined shape memory polymers with foldable structures to complete a deployable structure in space, but the deformation speed they used was relatively slow.

[0005] It can be seen that the current related existing technologies have the following main shortcomings: 1) The application of artificial muscles in folding and unfolding structures cannot achieve complete folding and unfolding. 2) During the folding and unfolding process, the center of gravity of the object is offset, which will cause the fiber driving performance to decrease and fail to achieve its linear contraction. 3) At present, the preparation of large pitch non-prestressed fibers generally requires a relatively complex process such as stretching / training. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide an active deformation folding and unfolding structure driven by artificial muscle fibers, and a manufacturing method and application thereof.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: In a first aspect, the present invention provides an active deformation folding and unfolding structure driven by an artificial muscle fiber, which comprises an artificial muscle fiber, a first folding and unfolding portion, and a second folding and unfolding portion; The first foldable part and the second foldable part are rotatably connected at the connecting shaft; the first foldable part is provided with a first matching part, and the second foldable part is provided with a second matching part; The artificial muscle fiber is non-fixedly matched with at least the first matching position and the second matching position, and is divided into a first section, a middle section and a second section, wherein the middle section is located between the first matching position and the second matching position, the first section extends from the first matching position toward the direction of the connecting axis, and the second section extends from the second matching position toward the direction of the connecting axis; When the artificial muscle fiber contracts, the first section and the middle section apply a first combined force to the first mating point, and the second section and the middle section apply a second combined force to the second mating point, and the first combined force and the second combined force drive the first mating point and the second mating point to approach each other.

[0008] In a second aspect, the present invention further provides a method for manufacturing an active deformation folding and unfolding structure driven by artificial muscle fibers, which comprises: preparing artificial muscle fibers; The artificial muscle fiber is assembled with the first folding portion and the second folding portion according to the connection method of the active deformation folding structure.

[0009] In a third aspect, the present invention also provides applications of the active deformation folding and unfolding structure in the fields of architecture, aerospace, robotics, medical equipment, and emergency rescue.

[0010] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention at least include: The active deformation folding structure provided by the present invention utilizes artificial muscle fibers arranged in triangular segments in combination with connection points that interfere with the two folding parts. It can achieve complete folding of the two folding parts with a contraction amount of less than 50%. It can restore to its original state when the artificial muscle fibers are stretched. It has the advantage of high degree of freedom and can be applied to multiple scenarios.

[0011] The preparation method provided by the present invention is simple and efficient in that it produces large-pitch bidirectional artificial muscle fibers by pre-twisting, then ply-twisting, and then annealing and separating. It can avoid the stretching / training process and other processes of producing large-pitch artificial muscles before. The produced non-prestressed large-pitch bidirectional artificial muscle fibers can be driven by applying current without load, and can restore to their original length after power failure.

[0012] The above description is only an overview of the technical solution of the present invention. In order to enable those skilled in the art to more clearly understand the technical means of the present application and implement them according to the contents of the specification, the following is a description of the preferred embodiments of the present invention in conjunction with detailed drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the driving principle of the active deformation folding and unfolding structure provided by a typical implementation case of the present invention; Figure 2 is a curve diagram showing the relationship between the active deformation folding and unfolding structure provided by a typical embodiment of the present invention and the contraction amount of the artificial muscle fiber; Figure 3 is a schematic diagram of a preparation process of artificial muscle fibers provided by a typical embodiment of the present invention; Figure 4 This is a physical photo of an artificial muscle fiber provided by a typical embodiment of the present invention; Figure 5 This is a driving performance test diagram of an artificial muscle fiber provided by a typical implementation case of the present invention; Figure 6 This is a cyclic drive test diagram of an artificial muscle fiber provided by a typical implementation case of the present invention; Figure 7 This is a photograph of the actual folding and unfolding process of an active deformation folding and unfolding structure provided in a typical implementation case of the present invention. DETAILED DESCRIPTION

[0014] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[0015] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0016] Moreover, relational terms such as “first” and “second” are merely used to distinguish one component or method step from another with the same name, but do not necessarily require or imply any such actual relationship or order between these components or method steps.

[0017] The embodiment of the present invention provides an active deformation folding and unfolding structure driven by an artificial muscle fiber, which includes an artificial muscle fiber, a first folding and unfolding portion, and a second folding and unfolding portion; The first foldable part and the second foldable part are rotatably connected at the connecting shaft; the first foldable part is provided with a first matching part, and the second foldable part is provided with a second matching part; The artificial muscle fiber is non-fixedly matched with at least the first matching position and the second matching position, and is divided into a first section, a middle section and a second section (usually refers to when the artificial muscle fiber is in a naturally relaxed state), the middle section is between the first matching position and the second matching position, the first section extends from the first matching position to the direction of the connecting axis, and the second section extends from the second matching position to the direction of the connecting axis; When the artificial muscle fiber contracts, the first section and the middle section apply a first combined force to the first mating point, and the second section and the middle section apply a second combined force to the second mating point. The first combined force and the second combined force drive the first mating point and the second mating point to approach each other, and then drive the first folding part and the second folding part to approach each other, so that complete folding can be achieved eventually.

[0018] In the above technical scheme, the main technical concept is to utilize the triangular structure of the artificial muscle fiber, one side of the triangle is the middle section, and the other two sides correspond to the first section and the second section. When the artificial muscle fiber shrinks as a whole, the three sections will be shortened, and thus will form relative sliding with the first mating point and the second mating point, thereby shortening the length of the middle section to the greatest extent. When folded to the final state, the first folding portion and the second folding portion are almost parallel, and the distance between the first mating point and the second mating point is shortened to the shortest. In the preferred embodiment, the first mating point and the second mating point are completely in conflict, and the middle section basically disappears at this time, and the artificial muscle fiber can be simplified as having only two parallel lines.

[0019] Hence, see Figure 1 and Figure 2 As shown, according to the triangle equivalent calculation, it can be known that even if a folding of 180° (generally less than 180° is required to apply a rotational torque to the folding portion) - 0° is achieved, it is only necessary for the artificial muscle fibers to have a 50% contraction amount. If the designed maximum expansion angle range is less than 180°, then the required microscopic contraction amount is smaller. Therefore, the outstanding technical contribution of the present invention is that it realizes the amplification of the contraction amount-folding angle, and utilizes the shape change of the triangle-double parallel lines to achieve a complete folding of 0°, which is currently impossible to achieve with the existing technology that uses artificial muscle fibers to drive the folding structure.

[0020] More specifically, Figure 1 It is a schematic diagram of the designed folding and unfolding structure and the driving amount required to complete folding and unfolding at different angles. Figure 1The "triangle" structure above is to put the fiber into the folding and spreading structure. During the contraction process, the fiber will present a "triangle" shape. As the fiber contracts, the side length of the "triangle" becomes shorter. Because the fiber pitch is reduced, one side of the "triangle" "disappears", thus forming a complete folding and spreading. In theory, only 50% of the drive amount is required to complete the folding and spreading of the maximum angle of 180°. The schematic diagram of the drive amount required for complete folding and spreading at different angles is shown in the figure below. Figure 2 As shown, the formula in the lower right corner is the formula for the driving amount required for complete folding at different angles, where ε is the required driving amount and θ is the angle formed by the right half of the folded structure and the plane.

[0021] As for the specific matching method of the artificial muscle fiber, on the one hand, a fixed matching method at both ends can be adopted, that is, in some embodiments, the end of the first section and / or the second section is fixedly arranged between the first matching position or the second matching position and the connecting axis, or fixedly arranged at the connecting axis.

[0022] Or a completely interference fit method is adopted, that is, in some embodiments, the first section and the second section are connected, so that the artificial muscle fiber surrounds the first fitting point, the second fitting point and the connecting axis, and there is also an interference fit at the connecting axis.

[0023] The above-mentioned various matching modes can realize a triangular structure, and utilize the interference matching and the combined force of the two sides at the matching point to drive the relative rotational movement of the folding and unfolding part.

[0024] In some embodiments, the first mating location and / or the second mating location is a hole structure, and the artificial muscle fiber passes through the hole structure.

[0025] In some embodiments, the contact surface between the artificial muscle fiber and the hole structure is a smooth surface.

[0026] In a typical exemplary case of the present invention, a polymer thin layer with certain stiffness is folded to form a connecting axis and two folding parts on both sides, and holes are punched on the folding surface and wrapped with a metal layer or other lubricating layer as two matching points. Then, artificial muscle fibers are passed through the two holes, and the two ends are connected and then surround the crease or the two ends are fixed near the crease to form an active deformation folding structure. However, this does not mean that the scope of implementation of the present invention is limited to this. The above exemplary cases are only simple solutions adopted for the convenience of experiments and demonstrations. For example, replacing the crease with a mechanical shaft, soft connection, etc., or replacing the holes with pulleys, sliding grooves, etc., or replacing the polymer thin layer with a mechanical arm, connecting rod, etc., are all equivalent deformation methods and are within the protection scope of the present invention.

[0027] As for the characteristics of the artificial muscle fiber itself, in some embodiments, when the artificial muscle fiber is in a natural relaxed state, the artificial muscle fiber has a stress-free spiral structure with a diameter of 400-100 μm and a pitch of 200-500 μm.

[0028] A second aspect of the embodiments of the present invention further provides a method for manufacturing an active deformation folding and unfolding structure driven by artificial muscle fibers, which comprises the following steps: preparing artificial muscle fibers; The artificial muscle fiber is assembled with the first folding portion and the second folding portion according to the connection method of the active deformation folding structure provided in any of the above embodiments.

[0029] In some embodiments, the method for preparing the artificial muscle fiber comprises: Providing conductive fiber filaments; Pre-twisting the conductive fiber to obtain twisted fiber; Winding the twisted fiber filaments around the outer periphery of the profile to form a spiral shape; The twisted fiber filaments are baked and shaped while maintaining the spiral shape, and then separated from the profile to obtain the artificial muscle fiber.

[0030] In some embodiments, the twisted fiber filament is pre-twisted to a critical state, wherein the critical state refers to a state where continued twisting will produce an over-twisted spontaneous spiral; In some embodiments, the spiral morphology is tightly wound, and any two adjacent turns of the twisted fibers are closely attached.

[0031] In some embodiments, the conductive fiber filaments include any one or more combinations of metal-plated polymer fibers, nickel-titanium alloy wires, and liquid crystal nanocomposite fibers; In some embodiments, the baking and shaping treatment is performed at a temperature of 150-200° C. and for a time of 50-200 min.

[0032] The third aspect of the embodiments of the present invention further provides the application of the active deformation folding structure provided by any of the above-mentioned embodiments in the fields of architecture, aerospace, robotics, medical equipment, and emergency rescue.

[0033] The technical solution of the present invention is further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present invention, and do not limit the scope of the present invention.

[0034] Example 1 This embodiment illustrates a preparation process of artificial muscle fibers, which is specifically as follows.

[0035] See also Figure 3 As shown, the non-prestressed large-pitch bidirectional artificial muscle is obtained by pre-twisting two strands of silver-coated nylon fibers until they are about to form a spiral structure, then twisting them together and winding them around a rigid shaft, then annealing and shaping them, and then separating them. The specific preparation steps are as follows: Step 1: Cut two 20cm silver-plated nylon fibers, fix one end of each fiber to the upper end of the rotating motor, clamp the other end, hang a 50g weight, turn on the rotating motor switch, insert the twist into the silver-plated nylon fiber, and turn off the rotating motor when the twist is about to form a spiral structure.

[0036] Step 2: Take the pre-twisted silver-plated nylon fiber obtained in step 1, stick the heads of the two fibers together with tape, then take an iron rod with an inner diameter of 0.3mm, and stick the fiber to the iron rod with tape. Note that the load cannot be removed during the process, then wrap the fiber around the iron rod to make sure that the fibers are close together and no pitch is left in the middle.

[0037] Step 3: Place the fiber wrapped around the iron rod into an oven, set the temperature to 180°, and anneal for 100 minutes to set the shape.

[0038] Step 4: Take out the fibers and iron rod with good quality, separate the two strands of fibers from the iron rod, and you can get large-pitch non-prestressed artificial muscle fibers. The artificial muscle fibers have a large pitch without load, can be contracted when powered on, and can recover to their original length when the power is off.

[0039] Example 2 This embodiment illustrates the performance test of the above-mentioned artificial muscle fiber, as shown below.

[0040] Figure 4 This is the morphology of the non-prestressed large-pitch bidirectional artificial muscle fiber. From left to right, there are two, four, and eight strands of silver-plated nylon fibers. It can be seen that the obtained fiber spiral structure is uniform, with a larger pitch in the middle. The diameter of the two-strand bidirectional artificial muscle fiber is about 400 um, the diameter of the four-strand bidirectional artificial muscle fiber is about 600 um, and the diameter of the eight-strand bidirectional artificial muscle fiber is about 1 mm.

[0041] Figure 5 This is the driving performance diagram of the non-prestressed large pitch bidirectional artificial muscle fiber. From left to right, they are the driving performance diagrams of two strands, four strands, and eight strands under appropriate current. It can be seen that whether it is two strands, four strands, or eight strands, a large driving amount can be achieved, because the driving amount of two strands is 50%, which can meet the requirement of folding and unfolding 180°. Therefore, the fibers used for the folding and unfolding structure are all two-strand bidirectional artificial muscle fibers.

[0042] Figure 6This is a test diagram of the cyclic performance of two bidirectional artificial muscle fibers driven at a current of 0.3A. It can be seen from the figure that during the driving cycle, the driving performance of the fiber did not show a significant decrease from the first cycle to the last cycle, so the fiber has good cyclic performance.

[0043] Example 3 This embodiment illustrates the driving process test of the active deformation folding and unfolding structure driven by the artificial muscle fibers, as shown below.

[0044] Figure 7 It is a basic folding unit that combines non-prestressed large pitch with folding structure, and the folding angles are 60°, 90°, and 120° respectively. The specific steps are to process the folding marks of the PET film first, and then fix the non-prestressed large pitch bidirectional artificial muscle fiber on the PET film in the shape of a "triangle". After power is turned on, the folding structure is fully folded and can be restored to its original state after 2s of power failure. From the figure below, it can be seen that no matter what the folding angle is, it can be fully folded when current is applied, and can maintain a fully folded state when power is continuously turned on, and can be restored to its original state after power failure.

[0045] In addition, it should be pointed out that the silver-plated nylon fiber in the above embodiment can be replaced by other materials with thermal response and self-recovery, such as nickel-titanium alloy wire, aramid, liquid crystal nanocomposite fiber, etc. The method of preparing large-pitch fibers by twisting can be replaced by winding the fibers around a rigid spiral with a pitch, and then annealing and shaping them and taking them out to obtain large-pitch fibers. The PET film in the folding structure can be replaced by other rigid films, such as polystyrene film, polypropylene film, high-temperature resistant aramid film, etc., and can also be equivalently replaced by other mechanical structures. The perforated metal material in the folding structure can be replaced by other polymer materials with less friction, such as polytetrafluoroethylene rings, ultra-high molecular weight polyethylene rings, polyamide rings, polyimide rings, etc., and of course it can be replaced by other matching structures such as pulleys and slideways.

[0046] Based on the above test results, it can be clearly seen that the active deformation folding structure provided in the embodiment of the present invention utilizes artificial muscle fibers arranged in triangular segments combined with connection points that interfere with the two folding parts, and can achieve complete folding of the two folding parts with a contraction amount of less than 50%. It can restore to its original state when the artificial muscle fibers are stretched, has the advantage of high degree of freedom, and can be applied to multiple scenarios.

[0047] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An active deformation folding structure driven by artificial muscle fibers, characterized in that: It includes artificial muscle fiber, a first folding part and a second folding part; The first foldable part and the second foldable part are rotatably connected at the connecting shaft; the first foldable part is provided with a first matching part, and the second foldable part is provided with a second matching part; The artificial muscle fiber is non-fixedly matched with at least the first matching position and the second matching position, and is divided into a first section, a middle section and a second section, wherein the middle section is located between the first matching position and the second matching position, the first section extends from the first matching position toward the direction of the connecting axis, and the second section extends from the second matching position toward the direction of the connecting axis; When the artificial muscle fiber contracts, the first section and the middle section apply a first combined force to the first mating point, and the second section and the middle section apply a second combined force to the second mating point, and the first combined force and the second combined force drive the first mating point and the second mating point to approach each other.

2. The active deformation folding structure according to claim 1, characterized in that: The end of the first section and / or the second section is fixedly arranged between the first fitting position or the second fitting position and the connecting shaft, or fixedly arranged at the connecting shaft; Alternatively, the first section and the second section are connected so that the artificial muscle fiber surrounds the first fitting location, the second fitting location and the connecting axis.

3. The active deformation folding structure according to claim 1, characterized in that: The first mating location and / or the second mating location is a hole structure, and the artificial muscle fiber passes through the hole structure.

4. The active deformation folding structure according to claim 3, characterized in that: The contact surface between the artificial muscle fiber and the hole structure is a smooth surface.

5. The active deformation folding structure according to claim 1, characterized in that: When the artificial muscle fiber is in a naturally relaxed state, the artificial muscle fiber has a stress-free spiral structure with a diameter of 400-1000 μm and a spiral pitch of 200-500 μm.

6. A method for manufacturing an active deformation folding structure driven by artificial muscle fibers, characterized in that: include: preparing artificial muscle fibers; The artificial muscle fiber is assembled with the first folding portion and the second folding portion according to the connection method of the active deformation folding structure according to any one of claims 1 to 5.

7. The manufacturing method according to claim 6, characterized in that: The preparation method of the artificial muscle fiber comprises: Providing conductive fiber filaments; Pre-twisting the conductive fiber to obtain twisted fiber; Winding the twisted fiber filaments around the outer periphery of the profile to form a spiral shape; The twisted fiber filaments are baked and shaped while maintaining the spiral shape, and then separated from the profile to obtain the artificial muscle fiber.

8. The method according to claim 7, characterized in that: The twisted fiber yarn is pre-twisted to a critical state, wherein the critical state refers to a state where continued twisting will produce an over-twisted spontaneous spiral; And / or, the spiral morphology is tightly wound, and any two adjacent turns of the twisted fibers are tightly fitted.

9. The manufacturing method according to claim 7, characterized in that: The conductive fiber filaments include any one or more combinations of metal-plated polymer fibers, nickel-titanium alloy wires, and liquid crystal nanocomposite fibers; And / or, the baking and shaping treatment is performed at a temperature of 150-200° C. and for a time of 50-200 min.

10. Application of the active deformation folding structure described in any one of claims 1 to 5 in the fields of architecture, aerospace, robotics, medical equipment, and emergency rescue.

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