A bidirectional torsional origami actuator based on layer interference variable stiffness structure

Abstract

The application discloses a bidirectional torsional origami actuator based on layer interference variable stiffness structure. The actuator comprises a Kresling origami cylinder structure, upper and lower end plates, layer interference variable stiffness structures, a gas source and a gas path control system. The layer interference variable stiffness structure is composed of multiple thin sheet layers and an external sealed film air bag. The layer interference variable stiffness structure is tightly attached to the fold surface of different regions of the Kresling origami cylinder structure. By adjusting the negative pressure of different layer interference variable stiffness structures, different fold combinations can be selectively activated to complete the rapid switching of the torsional direction of the Kresling origami cylinder structure. By applying different negative pressures to all layer interference variable stiffness structures, the overall torsional stiffness and bending stiffness of the actuator can be actively adjusted. The actuator can realize the repeatable programming of the torsional deformation direction and the overall stiffness through local stiffness regulation, has the advantages of fast response, reusable structure and simple manufacturing, and is suitable for repeatable programming soft robots or deformation mechanisms.

Description

Technical Field

[0001] This invention relates to deformable structures and soft actuation technology, and in particular to a bidirectional torsional origami actuator based on a layer interference variable stiffness structure, which can be used in reprogrammable soft robots or deformable mechanisms. Background Technology

[0002] With the rapid development of flexible robots, intelligent grippers, and deformable structures, torsional actuators have been widely used in flexible structure control, microrobots, and adjustable structural components. However, existing flexible torsional actuators have several limitations: their rotation direction is difficult to control precisely; most actuators cannot switch between left-hand and right-hand rotation modes during torsion through internal structural adjustments, resulting in fixed driving directions or requiring additional complex mechanical structures for switching; local stiffness is not adjustable; the structural stiffness of existing actuators is usually determined by the material and overall geometry, making it difficult to flexibly adjust in local areas, thus limiting the adaptability of torsional actuators in different application scenarios; reprogrammability is poor; traditional torsional actuators usually rely on a single driving mode, making it impossible to quickly switch and repeatedly adjust the rotation direction and stiffness state, reducing system flexibility and ease of operation; in addition, some solutions are complex to manufacture and difficult to seal, requiring multi-part assembly or complex machining, making mass production difficult and costly while ensuring airtightness and driving stability. Therefore, there is an urgent need for a flexible torsional actuator with a simple structure, controllable rotation direction, adjustable local stiffness, reprogrammability, and ease of manufacture to meet the diverse needs of flexible robots, intelligent grippers, and deformable mechanisms in practical applications. Summary of the Invention

[0003] The purpose of this invention is to overcome the limitations of existing origami actuators in terms of rotation direction control and stiffness adjustment, and to provide a bidirectional torsional origami actuator based on a layer-interference variable stiffness structure. By arranging a layer-interference variable stiffness structure in a specific area of ​​the origami structure and achieving local stiffness adjustment through air circuit control, the rotation direction of the origami structure can be programmably switched. The actuator of this invention has a simple structure, reliable function, and is easy to manufacture, and is suitable for reprogrammable rotation drives, shape transformation, or gripping / deformation mechanisms.

[0004] The technical solution adopted in this invention is as follows: A bidirectional torsional origami actuator based on a layer-interference variable stiffness structure includes a Kresling origami cylinder structure, upper and lower end plates, a layer-interference variable stiffness structure, an air source, and an air path control system. The end plates include upper and lower plates. The Kresling origami cylinder structure is composed of multiple circumferentially arranged "X"-shaped origami structures, preferably using four folds to form a quadrangular prism shape. The Kresling origami cylinder structure and the upper and lower end plates form an airtight main air chamber. The origami structure has two sets of staggered folds, forming a left-handed fold group and a right-handed fold group, respectively.

[0005] Furthermore, the present invention includes two sets of layer interference variable stiffness structures (each set comprising a layer interference variable stiffness structure one and a layer interference variable stiffness structure two), correspondingly located on the symmetrical sides of the origami structure and closely fitted to the folded surface. Specifically, layer interference variable stiffness structure one is fitted to the upper right portion of the folded surface along the upper right-lower left crease; layer interference variable stiffness structure two is fitted to the upper left portion of the folded surface along the upper left-lower right crease. The layer interference variable stiffness structure is triangular in shape, and its size matches half of the rectangle on the side of the Kresling origami cylinder structure; the bottom of the layer interference variable stiffness structure is connected to the upper end plate.

[0006] Furthermore, the layered interference variable stiffness structure consists of multiple layers of thin sheets and a sealed film air bag. The multiple layers of thin sheets are stacked and placed inside the film air bag. The internal multiple layers of thin sheets can be multiple layers of frosted PET sheets, specifically PET sheets with a certain interfacial friction coefficient stacked in a predetermined direction, with each sheet maintaining slight relative slippage. The film air bag is an airtight film air bag used to generate uniform compression force during air extraction. When no negative pressure is applied, the inside of the film air bag is approximately at normal pressure. At this time, there is only static friction between different PET layers, and the layers can move relative to each other within a limited range, and the overall structure exhibits a flexible state. When negative pressure is applied to the film air bag, the outer film contracts inward due to the pressure difference, generating a uniform extrusion force facing the center, causing all PET sheets to be tightly pressed together. As a result, the interlayer normal pressure increases significantly, the friction force is multiplied, and the originally relatively slippage-free multilayer structure is "locked" into a whole structure, with its equivalent bending stiffness and torsional stiffness greatly improved. Therefore, when different negative pressures are applied to different layers of the variable stiffness structure, the bending stiffness of the structure changes, thereby enabling active control of the local stiffness of the Kresling origami tube structure. At this time, when negative pressure is applied to the main air chamber, the Kresling origami tube structure can undergo torsional-compression coupling deformation.

[0007] Furthermore, by adjusting the air pressure in the main air chamber and the two sets of layer interference variable stiffness structures, the torsional direction selection and reprogrammable function of the origami structure (Kresling origami cylinder structure) can be achieved through selective inflation or deflation. Specifically, when negative pressure is applied to a certain set of layer interference variable stiffness structures (one set consists of the upper left part of the folded surface, and the others form another set), the bending stiffness of the creases in that area increases, causing that set of creases to become ineffective, leaving only the other set of creases retaining folding ability. By activating Kresling creases with different chirality, the torsional direction can be selected. During the driving process, the air circuit control system, connected to a negative or positive pressure air source, applies negative pressure to the main air chamber to cause the origami cylinder to contract and torsion, while applying positive pressure returns the overall structure to its initial state, achieving reprogrammable torsional action.

[0008] Furthermore, by adjusting the negative pressure of different layers of the variable stiffness interference structure, different crease combinations can be selectively activated. Through selective inflation or deflation, the torsional direction of the Kresling origami tube structure can be rapidly switched, thereby achieving the bidirectional torsional function of the actuator. The specific method is as follows: When a negative pressure is applied to a set of layered interference variable stiffness structures covering the upper left part of the crease, the bending stiffness of the layered interference variable stiffness structures increases, causing the right-handed crease to fail and only the left-handed crease group to be activated. The actuator will undergo compression-leftward torsional coupling deformation under negative pressure. Conversely, when a negative pressure is applied to another set of layered interference variable stiffness structures covering the upper right part of the crease, its bending stiffness increases, causing the left-handed crease to fail. The actuator will then undergo compression-rightward torsional coupling deformation under negative pressure.

[0009] Furthermore, applying negative pressure to different layer-interference variable stiffness structures increases their bending stiffness and also alters the local bending stiffness control of the corresponding folds. By applying different negative pressures to all layer-interference variable stiffness structures in the actuator, the overall torsional stiffness and bending stiffness of the actuator can be actively adjusted.

[0010] Furthermore, by simultaneously applying negative pressure to the two sets of layer interference structures, the panel stiffness of all folded surfaces of the actuator can be increased, thereby increasing the overall stiffness of the origami structure under any deformation state and improving the load capacity of the actuator.

[0011] Furthermore, the Kresling origami cylinder structure is preferably made of PVC sheet, and its preparation process is as follows: First, the PVC sheet is processed using laser cutting technology to form a semi-cut origami pattern. The creases in the origami pattern are processed into slits or grooves of a preset width. The PVC sheet with the origami pattern is then attached to transparent tape, and the material of the creases is removed. Next, a double-sided adhesive layer is adhered to the surface of the origami pattern, and a TPU film is adhered to the double-sided adhesive layer to form a laminated structure. Finally, the resulting laminated structure is folded along the creases to form a quadrangular prism cylinder. The connection between the cylinder and the upper and lower end plates is sealed to obtain a Kresling origami cylinder structure with good airtightness. The end plates are manufactured using PLA material through 3D printing. The internal structure of the variable stiffness membrane air bag of the layered interference structure preferably uses multiple layers of PET sheets. The overall structure is lightweight, easy to process, and suitable for mass production.

[0012] Furthermore, the air source includes a positive pressure air source and a negative pressure air source; the air path control system consists of a power supply, a microcontroller, a pressure reducing valve, a two-position three-way solenoid valve, and a conduit system; the air path control system is connected to the negative pressure air source or the positive pressure air source and is used to control the air extraction or inflation of the main air chamber and the two sets of layered interference variable stiffness structures; the conduit system includes air pipes, power lines, and signal lines; the microcontroller is connected to the two-position three-way solenoid valve through the signal line, and uses high and low level signals to switch the path of the two-position three-way solenoid valve; both the positive pressure air source and the negative pressure air source are connected to the pressure reducing valve through air pipes; the pressure reducing valve is used to control the magnitude of positive or negative pressure; the two-position three-way solenoid valve is connected to the pressure reducing valve through air pipes, and the two-position three-way solenoid valve controls the airflow path to inflate or evacuate the main air chamber and the two sets of layered interference variable stiffness structures. The power supply supplies power to the pressure reducing valve and the two-position three-way solenoid valve through the power line.

[0013] The present invention also provides a bidirectional torsional drive control method for the above-mentioned driver, comprising the following steps: Step 1. Apply negative pressure only to a group of layered interference variable stiffness structures covering the upper left part of the fold, so that the right-handed creases are ineffective and only the left-handed crease group is activated; Step 2. Control the negative pressure air source to apply negative pressure to the main air chamber. At this time, the actuator rotates counterclockwise, and compression-counterclockwise torsional coupling deformation occurs. Step 3. After complete deformation, negative pressure is applied to both sets of layer interference variable stiffness structures at the same time. Both of them have large bending stiffness, the overall stiffness of the structure increases, the load capacity of the actuator is improved, and the actuator can complete the control task that requires large structural stiffness. Step 4. After the operation is completed, stop applying negative pressure to the two sets of layer interference variable stiffness structures, and control the positive pressure air source to fill the main air chamber until the actuator returns to the initial state. Step 5. Apply negative pressure only to the other set of layer interference variable stiffness structures covering the upper right part of the fold, so that the left-handed crease is ineffective and only the right-handed crease group is activated; repeat step 2 above, the actuator rotates in the clockwise direction, and compression-clockwise torsional coupling deformation occurs; then repeat step 3 to adjust the overall stiffness of the structure. Step 6. Repeat step 4 above to restore the driver to its initial state.

[0014] The beneficial effects of this invention are: This invention employs a bidirectional torsional origami actuator based on a layer-interference variable stiffness structure. The layer-interference variable stiffness structure enables local stiffness control of the origami structure, and this stiffness control allows for active switching of the rotational deformation direction. By selectively applying negative pressure to different sets of layer-interference variable stiffness structures, the origami structure can switch between left-handed and right-handed Kresling modes, thus precisely controlling the actuator's torsional direction. Independent control of the air pressure in the main air chamber and the layer-interference variable stiffness structure allows for repeated cyclic switching of the origami structure's rotational direction and stiffness state, achieving reprogrammable torsional actuation. The Kresling origami structure can be fabricated using PVC laser cutting, and the end plates can be 3D printed using PLA material. The layer-interference variable stiffness structure is composed of stacked PET sheets, a mature manufacturing process easily simplifies mass production. The air circuit system of the main air chamber and the layer-interference variable stiffness structure can be centrally controlled; active control of the rotational direction and stiffness can be achieved using a small number of solenoid valves and pressure reducing valves, facilitating integration with other systems in industrial or experimental environments. This invention provides a reprogrammable software actuator capable of bidirectional torsion and variable stiffness, which has significant advantages such as strong innovation, high reliability, wide adaptability, simple operation and easy mass production. It can be widely used in flexible robots, intelligent grippers and deformable mechanisms. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of a bidirectional torsion folding driver based on a layer interference variable stiffness structure according to the present invention. Figure 2 This is a schematic diagram of the layer interference variable stiffness structure and its cross-section of the present invention; Figure 3 This is a schematic diagram of the unfolded Kresling origami tube structure of the present invention; Figure 4 A schematic diagram showing the arrangement of the layered variable stiffness structure; Figure 5 This is a schematic diagram of the gas circuit control system; Among them: 1-end plate, 2-Kresling origami cylinder structure, 3-layer interference variable stiffness structure, 4-layer interference variable stiffness structure air passage, 5-main air chamber air passage. Detailed Implementation

[0016] The following description, in conjunction with the accompanying drawings, further illustrates a bidirectional torsional folding actuator based on a layered interference variable stiffness structure according to the present invention.

[0017] like Figure 1 As shown, the actuator of this invention mainly includes an end plate 1, a Kresling origami cylinder structure 2 composed of an "X"-shaped origami structure, two sets of layer interference variable stiffness structures 3, an air source and air path control system, wherein the air source includes a positive pressure air source and a negative pressure air source, and the air path control system includes a layer interference variable stiffness structure air path 4, a main air chamber air path 5, a power supply, a microcontroller, a pressure reducing valve, a two-position three-way solenoid valve, and a conduit system. There are two end plates 1, located at the top and bottom of the actuator respectively, specifically thin plates of the same size with a regular quadrilateral cross section, forming the upper and lower surfaces of the actuator. In the initial state, the upper and lower end plates do not rotate relative to each other. The "X"-shaped origami structure is arranged in a quadrangular prism shape along the circumference to form a cylinder structure (i.e., a Kresling origami cylinder structure) that cooperates with the end plate 1. The top and bottom of the Kresling origami cylinder structure 2 are tightly bonded to the end plate 1 using double-sided adhesive tape, and UV-cured adhesive is applied to the contact surfaces of the tape to ensure airtightness between the Kresling origami cylinder structure 2 and the end plate 1, thereby forming a stable main air chamber. Under negative pressure, the Kresling origami cylinder structure 2 can undergo torsional-compression coupling deformation.

[0018] like Figure 2 The diagram shows the layer-interference variable stiffness structure 3 of the present invention and its cross-sectional schematic diagram. The structure is composed of an inner multi-layered frosted PET sheet and an outer sealed film air bag. The layer-interference variable stiffness structure is triangular in shape, and its dimensions match half of the rectangular side profile of the Kresling origami tube structure. The bottom of the layer-interference variable stiffness structure is connected to the upper end plate. The inner multi-layered frosted PET sheets are PET sheets with a certain coefficient of interfacial friction stacked in a predetermined direction, allowing for slight relative slippage between the sheets. The outer sealed film air bag is an airtight film air bag made through heat sealing or bonding processes, used to generate uniform compression force during air extraction. When no negative pressure is applied, the inside of the air bag is approximately at atmospheric pressure. At this time, only static friction exists between the different PET layers, and the layers can move relative to each other within a limited range, resulting in a flexible overall structure. When negative pressure is applied to the film air bag, the outer film contracts inward due to the pressure difference, generating a uniform extrusion force facing the center, causing all the PET sheets to be tightly pressed together. As a result, the interlayer normal pressure increases significantly, the friction force is multiplied, and the multilayer structure that could originally slide relative to each other is "locked" into an integral structure, and its equivalent bending stiffness and torsional stiffness are greatly improved.

[0019] like Figure 3The diagram shows the unfolded Kresling origami tube structure 2 of the present invention, where the protruding creases are mountain creases and the recessed creases are valley creases. The Kresling origami tube structure 2 consists of folded surfaces and creases. Each folded surface has two sets of staggered creases (creases with two different chiral directions), and both sets of staggered creases are valley creases. One set of creases is arranged along the upper right-lower left direction, located in the upper left part of the folded surface, forming a left-handed Kresling origami structure, which tends to rotate counterclockwise when compressed. The other set of creases is arranged along the upper left-lower right direction, located in the upper right part of the folded surface, forming a right-handed Kresling origami structure, which tends to rotate clockwise when compressed. The two sets of creases intersect to form an "X" shaped origami structure. This origami structure design allows for control of the rotation direction while ensuring that the origami structure has both flexible folding capability and maintains overall stability under stress.

[0020] like Figure 4 As shown, this invention arranges two sets of layer interference variable stiffness structures 3 in a specific area of ​​the origami structure, including layer interference variable stiffness structure one and layer interference variable stiffness structure two, respectively located on the prism side of the Kresling origami cylinder structure 2. When different negative pressures are applied, the bending stiffness of the structure increases, thereby achieving active control of the local stiffness of the Kresling origami cylinder structure 2. Specifically, layer interference variable stiffness structure one is bounded by the right-handed crease of the folded surface and fits into the upper right part of the folded surface; layer interference variable stiffness structure two is bounded by the left-handed crease of the folded surface and fits into the upper left part of the folded surface. When negative pressure is applied to layer interference variable stiffness structure one through the air passage 4 of the layer interference variable stiffness structure 3, the left-handed crease in the area covered by this set of layer interference variable stiffness structures 3 becomes "ineffective" due to the hardening of the layer interference variable stiffness structure 3 and a significant increase in bending stiffness, that is, it no longer participates in the origami deformation, so only the right-handed crease group retains the folding ability. Conversely, when negative pressure is applied to the second layer of variable stiffness structure through the air passage 4 of the layer interference variable stiffness structure, only the left-handed crease group retains its folding ability. By switching the air pressure state of different groups of layer interference variable stiffness structures 3, the rotation direction of the origami structure can be programmably switched.

[0021] like Figure 5As shown, the gas source of this invention includes a positive pressure gas source and a negative pressure gas source. The gas path control system consists of a power supply, a microcontroller, a pressure reducing valve, a two-position three-way solenoid valve, and a conduit system. The gas path control system is connected to either the negative or positive pressure gas source and is used to control the pumping or filling of the main air chamber and the two sets of layered interference variable stiffness structures 3. The conduit system includes air pipes, power lines, and signal lines. The microcontroller is connected to the two-position three-way solenoid valve via a signal line, using high and low level signals to switch the valve's path. Both the positive and negative pressure gas sources are connected to the pressure reducing valve via air pipes. The pressure reducing valve controls the magnitude of the positive or negative pressure. The two-position three-way solenoid valve is connected to the pressure reducing valve via an air pipe, and controls the airflow path to pump or fill the main air chamber and the two sets of layered interference variable stiffness structures 3. The power supply provides power to the pressure reducing valve and the two-position three-way solenoid valve via a power line.

[0022] Specifically, the main air chamber air passage 5 controls the inflation or deflation of the main air chamber through a positive pressure reducing valve, a negative pressure reducing valve, and a two-position three-way solenoid valve, thereby achieving the overall expansion and contraction deformation of the origami structure. The two sets of layer interference variable stiffness structure air passages 4 are controlled by two other negative pressure reducing valves and two two-position three-way solenoid valves, respectively, to adjust the stiffness state of different sets of layer interference variable stiffness structures 3, thereby selectively activating the left-handed or right-handed crease groups of the Kresling origami structure, realizing the selection of the rotation direction of the origami structure and the adjustment of the overall stiffness.

[0023] In this invention, the independent method and process by which the actuator achieves left-handed and right-handed rotation is as follows: When negative pressure is applied to the first layer of the variable stiffness structure with interference, only the right-handed crease group retains the folding ability. At this time, applying negative pressure to the main air chamber causes the folding structure to rotate to the right, that is, viewed from above, the upper end plate rotates clockwise relative to the lower end plate. Conversely, when negative pressure is applied to the second layer of the variable stiffness structure with interference, only the left-handed crease group retains the folding ability. At this time, applying negative pressure to the main air chamber causes the folding structure to rotate to the left, that is, viewed from above, the upper end plate rotates counterclockwise relative to the lower end plate. After the torsional action is completed, applying positive pressure to the main air chamber can restore the actuator to its initial state, realizing the reprogrammable torsional direction.

[0024] In this invention, each layer of the actuator's variable stiffness structure 3 is controlled by an independent pneumatic unit, allowing for the application of negative pressure of varying amplitudes. Since each layer of the variable stiffness structure 3 is distributed at different circumferential positions within the Kresling origami tube structure 2, the increase in stiffness under negative pressure creates uneven bending and torsional constraints circumferentially within the Kresling origami tube structure 2. By applying different degrees of negative pressure to the different layers of the variable stiffness structure 3, the overall torsional and bending stiffness of the actuator can be continuously varied between high and low stiffness.

[0025] The bidirectional torsional drive control method for the actuator of the present invention includes the following steps: Step 1. Apply negative pressure only to a group of layer interference variable stiffness structures 3 covering the upper left part of the fold, so that the right-handed creases are ineffective and only the left-handed crease group is activated; Step 2. Control the negative pressure air source to apply negative pressure to the main air chamber. At this time, the actuator rotates counterclockwise, and compression-counterclockwise torsional coupling deformation occurs. Step 3. After complete deformation, negative pressure is applied to both sets of layer interference variable stiffness structures 3 at the same time. Both of them have large bending stiffness, the overall stiffness of the structure increases, the load capacity of the actuator is improved, and the actuator can complete the control task that requires large structural stiffness. Step 4. After the operation is completed, stop applying negative pressure to the two sets of layer interference variable stiffness structures 3, and control the positive pressure air source to fill the main air chamber until the actuator returns to the initial state. Step 5. Apply negative pressure only to the other set of layer interference variable stiffness structures 3 covering the upper right part of the fold, so that the left-handed crease is ineffective and only the right-handed crease group is activated; repeat step 2 above, the actuator rotates in the clockwise direction, and compression-clockwise torsional coupling deformation occurs; then repeat step 3 to adjust the overall stiffness of the structure. Step 6. Repeat step 4 above to restore the driver to its initial state.

[0026] The actuator of this invention achieves local stiffness adjustment and rotation direction selection by arranging a layer of interference variable stiffness structure 3 in a specific area of ​​the origami structure and combining it with pneumatic control. It can complete reprogrammable torsional actuation without complex mechanical structures. The actuator is compact, easy to manufacture, and simple to operate. Through local stiffness adjustment, it can repeatedly switch between left-handed and right-handed Kresling origami structures, achieving highly reliable repetitive torsional movements and reprogrammable overall stiffness. It has the advantages of fast response, reusable structure, and simple manufacturing. The actuator of this invention is suitable for reprogrammable soft robots or deformable mechanisms and has broad application prospects.

Claims

1. A bidirectional torsional paper-folding actuator based on a layer-interference variable stiffness structure, characterized in that, The system includes a Kresling origami tube structure, end plates, a layer-interference variable stiffness structure, an air source, and an air path control system. The end plates consist of an upper end plate and a lower end plate; the lower end plate is fixed, while the upper end plate is freely rotatable. The Kresling origami tube structure connects with the upper and lower end plates to form an airtight inner cavity, serving as the main air chamber. The creases of the Kresling origami tube structure consist of left-handed and right-handed crease groups, which intersect to form an "X" shaped crease. The layer-interference variable stiffness structure consists of multiple thin sheets and a sealed thin-film air bag. The multiple thin sheets are stacked and placed... Inside the thin-film air bag, the layer interference variable stiffness structure is divided into two groups and closely attached to the folded surfaces of different areas of the Kresling origami cylinder structure; the air source includes a positive pressure air source and a negative pressure air source; the air path control system works in conjunction with the air source to provide negative or positive pressure drive to the main air chamber and the layer interference variable stiffness structure; when different negative pressures are applied to all the layer interference variable stiffness structures, the local bending stiffness of the structure changes, thereby realizing the active control of the local stiffness of the Kresling origami cylinder structure. At this time, when negative pressure is applied to the main air chamber, the Kresling origami cylinder structure can undergo torsional-compression coupling deformation.

2. The bidirectional torsional paper-folding actuator based on a layer-interference variable stiffness structure according to claim 1, characterized in that: The layer interference variable stiffness structure is triangular in shape, and its size matches half of the rectangular side of the Kresling origami tube structure. The bottom of the layer interference variable stiffness structure is connected to the upper end plate. Each layer interference variable stiffness structure is bounded by a left-handed or right-handed crease and fits into the upper left or upper right part of the folded surface. Any two adjacent layer interference variable stiffness structures fit into the upper left or upper right part of the folded surface, respectively. Each film air bag is provided with a layer interference variable stiffness structure air passage. The layer interference variable stiffness structure air passage is connected to a negative pressure air source. After applying negative pressure to the layer interference variable stiffness structure, its bending stiffness increases.

3. The bidirectional torsional paper-folding actuator based on a layer-interference variable stiffness structure according to claim 2, characterized in that: By adjusting the negative pressure of different layers of variable stiffness interference structures, different crease combinations can be selectively activated. Selective inflation or deflation allows for rapid switching of the torsional direction of the Kresling origami tube structure, thus enabling reprogrammable torsional deformation direction of the actuator. The specific method is as follows: When a negative pressure is applied to a set of layered interference variable stiffness structures covering the upper left part of the crease, the bending stiffness of the layered interference variable stiffness structures increases, causing the right-handed crease to fail and only the left-handed crease group to be activated. The actuator will undergo compression-to-left torsional coupling deformation under negative pressure. Conversely, when a negative pressure is applied to another set of layered interference variable stiffness structures covering the upper right part of the crease, its bending stiffness increases, causing the left-handed crease to fail. The actuator will undergo compression-to-right torsional coupling deformation under negative pressure. During the driving process, applying negative pressure to the main air chamber causes the actuator to contract and twist, while applying positive pressure to the main air chamber causes the actuator to return to its initial state, thus achieving a reprogrammable twisting motion.

4. The bidirectional torsional paper-folding actuator based on a layered interference variable stiffness structure according to claim 1, characterized in that: The Kresling origami tube structure is made of PVC.

5. A bidirectional torsional paper-folding actuator based on a layered interference variable stiffness structure according to claim 1, characterized in that: Both the upper and lower end plates are made of PLA material.

6. The bidirectional torsional paper-folding actuator based on a layered interference variable stiffness structure according to claim 1, characterized in that: The multilayer sheet of the layer interference variable stiffness structure is made of PET material.

7. A bidirectional torsional paper-folding actuator based on a layer-interference variable stiffness structure according to claim 1, characterized in that: The gas source and gas path control system includes a positive pressure gas source, a negative pressure gas source, a pressure reducing valve, and a two-position three-way solenoid valve for controlling the main gas chamber, as well as a negative pressure gas source, a pressure reducing valve, and a two-position three-way solenoid valve for the layer interference variable stiffness structure. By switching different gas paths and controlling the negative pressure value, the torsional deformation direction can be quickly switched and reprogrammable.

8. The bidirectional torsional drive control method for the actuator as described in any one of claims 1-7, characterized in that: Includes the following steps: Step 1. Apply negative pressure only to a group of layered interference variable stiffness structures covering the upper left part of the fold, so that the right-handed creases are ineffective and only the left-handed crease group is activated; Step 2. Control the negative pressure air source to apply negative pressure to the main air chamber. At this time, the actuator rotates counterclockwise, and compression-counterclockwise torsional coupling deformation occurs. Step 3. After complete deformation, negative pressure is applied to both sets of layer interference variable stiffness structures at the same time. Both of them have large bending stiffness, the overall stiffness of the structure increases, the load capacity of the actuator is improved, and the control task requiring large structural stiffness can be completed. Step 4. After the operation is completed, stop applying negative pressure to the two sets of layer interference variable stiffness structures, and control the positive pressure air source to fill the main air chamber until the actuator returns to the initial state. Step 5. Apply negative pressure only to the other set of layer interference variable stiffness structures covering the upper right part of the fold, so that the left-handed crease is ineffective and only the right-handed crease group is activated; repeat step 2 above, the actuator rotates in the clockwise direction, and compression-clockwise torsional coupling deformation occurs; then repeat step 3 to adjust the overall stiffness of the structure. Step 6. Repeat step 4 above to restore the driver to its initial state.

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