A 3D deformable variable stiffness skin based on laminar blockage mechanism and its preparation method

Abstract

The invention discloses a 3D deformable variable-rigidity skin based on a laminar blocking mechanism and a preparation method thereof, which relates to the field of robot technology and comprises a lower silicone rubber membrane, a group of columns, a group of discrete blocking elements, a vacuum tube and an upper silicone rubber membrane, wherein a group of columns are arranged on the surface of the lower silicone rubber membrane, each column is sleeved with a plurality of layers of discrete blocking elements, wherein the multi-layer discrete blocking elements constitute a blocking layer, one end of the vacuum tube is arranged on the lower silicone rubber membrane, and the other end thereof is connected to a vacuum pump, and the upper silicone rubber membrane is coated and sealed on the lower silicone rubber membrane, and by adopting discrete blocking elements instead of traditional whole-piece blocking elements and adopting multi-layer blocking elements, the skin has better flexibility, and at the same time, when greater rigidity is required, greater rigidity can be provided, thereby having better environmental adaptability.

Description

Technical Field

[0001] The invention relates to the field of robotics, and in particular to a 3D deformable variable-rigidity skin based on a laminar blockage mechanism and a preparation method thereof. Background Art

[0002] Soft robots have aroused widespread interest in the field of robotics and related fields due to their high flexibility, ductility, adaptability and safety, and are widely used in various fields such as medicine, military, and industry. Soft robotics technology is a branch of robotics technology. It is generally made of flexible and adaptive materials and has a soft body. However, the lack of body stiffness has seriously restricted the development of soft robots. Variable stiffness robots add variable stiffness modules to soft robots to combine the advantages of both, with good flexibility and high stiffness. In view of the current research on variable stiffness in the field of soft robots, the blocking variable stiffness method is widely used in the demand for variable stiffness of soft robots because of its simple design, low cost, and no need to rely on temperature.

[0003] The blocking-to-stiffness method can achieve mutual conversion between fluid state and solid state. There are three different types of blocking mechanisms in soft robots: particle blocking, laminar blocking and fiber blocking. These three methods have similar structures, all of which are filled with non-stretchable materials in the film; the same principle, all of which use negative pressure to increase the shear stress of the material in the elastic film; currently, particle blocking and laminar blocking are more commonly used. Particle blocking is highly deformable in the fluid state and has strong conformability to the outside world, but it requires a large number of blocking particles, is heavy, and is not precisely controlled; currently, laminar blocking can provide a large range of stiffness changes, but has poor deformation ability and weak adaptability to the environment. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a 3D deformable variable-rigidity skin based on the laminar blockage mechanism and a preparation method thereof. By improving the structure of the laminar blockage element, the skin has better flexibility. At the same time, when greater rigidity is required, it can provide greater rigidity, thereby having better environmental adaptability.

[0005] The technical solution of the present invention is as follows:

[0006] A 3D deformable variable stiffness skin based on laminar blocking mechanism comprises a lower silicone rubber membrane, a group of columns, a group of discrete blocking elements, a vacuum tube and an upper silicone rubber membrane, wherein a group of columns are arranged on the surface of the lower silicone rubber membrane, each column is provided with a plurality of layers of discrete blocking elements, wherein the multiple layers of discrete blocking elements constitute a blocking layer, one end of the vacuum tube is arranged on the lower silicone rubber membrane, and the other end thereof is connected to a vacuum pump, and the upper silicone rubber membrane is coated and sealed on the lower silicone rubber membrane.

[0007] Furthermore, the 3D deformable variable-rigidity skin based on the laminar blockage mechanism is characterized in that the shape of the discrete blockage element is hexagonal, circular or rectangular, and its material is PET.

[0008] The present invention also proposes a method for preparing a 3D deformable variable stiffness skin based on a laminar flow blocking mechanism, comprising the following steps:

[0009] 1) According to the preset skin size, a mold 1 for the lower silicone rubber membrane and a mold 2 for the upper silicone rubber membrane are respectively manufactured by laser cutting method, and are put into use after the manufacturing is completed;

[0010] 2) Make columns and discrete blocking elements for future use;

[0011] 3) Pour the two silicone rubbers into a beaker, stir and mix them with a glass rod, and after they are fully mixed, put them into a vacuum drying oven for vacuum treatment until no bubbles emerge in the beaker, and then slowly pour the mixture into the mold 1 and mold 2 prepared in step 1) until the mixture reaches the edge, and then place the two molds on a flat surface for curing. After the curing is completed, the lower silicone rubber film and the upper silicone rubber film are obtained and set aside;

[0012] 4) According to the pre-layout requirements, fix the pillars made in step 2) on the surface of the lower silicone rubber membrane prepared in step 3) with tweezers, then fix the discrete blocking elements made in step 2) on the pillars, and then seal the tops of the pillars with silicone rubber adhesive;

[0013] 5) After step 4) is completed, a vacuum tube is set on the surface of the lower silicone rubber film, and then the upper silicone rubber film prepared in step 3) is covered and the edges are pressed to seal, and the skin to be prepared can be obtained;

[0014] 6) Perform an air tightness test on the skin prepared in step 5).

[0015] Furthermore, in step 1), mold 1 and mold 2 have the same structure and are both transparent molds.

[0016] Furthermore, the specific operation of step 2) is as follows: using a laser cutting machine to cut the PET into a number of discrete plugging elements; cutting the silicone rubber tube into a number of 10 mm long columns.

[0017] Furthermore, in step 3), the volume ratio of the two silicone rubbers is 1:1; the two silicone rubbers that are fully mixed are placed under a negative pressure condition of -0.1 MPa for 2-3 minutes until no bubbles emerge in the beaker; and the materials in mold 1 and mold 2 are cured for 7 hours.

[0018] Furthermore, in step 4), an adhesive is applied around the outer surface of the pillar to form a ring.

[0019] Furthermore, in step 5), one end of the vacuum tube is located on the lower silicone rubber film, and the end is outside the outermost column.

[0020] Furthermore, in step 6), if the skin leaks, it can be filled with a syringe filled with silicone rubber.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1) By adopting the technical solution of the present invention, by adopting discrete blocking elements instead of traditional whole-piece blocking elements, and by adopting multi-layer blocking elements, the skin prepared by the method of the present invention has good flexibility, and at the same time, when greater rigidity is required, it can provide greater rigidity, thereby having better environmental adaptability;

[0023] 2) When the skin is at atmospheric pressure, that is, when no vacuum is applied, the skin is flexible and can achieve 3D deformation to envelop objects with different shapes and contours. At this time, the skin can achieve reversible multi-directional stretching and has good conformability;

[0024] 3) When the skin is evacuated, the discrete blocking elements inside the skin are compressed and the stiffness of the skin is increased. At this time, the skin can maintain its shape and contour before activation and has a stronger bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the variable stiffness skin side structure of the present invention;

[0026] Figure 2 It is a schematic diagram of the top view structure of the variable stiffness skin of the hexagonal discrete blocking element in the present invention;

[0027] Figure 3 It is a schematic diagram of the structure of the blocking layer of the inner structure of the skin under atmospheric pressure of the present invention;

[0028] Figure 4 It is a schematic diagram of the structure of the blocking layer of the inner structure of the skin under negative pressure of the present invention;

[0029] Figure 5 It is a comparison chart of the effect of different discrete blocking elements with variable stiffness;

[0030] Figure 6 Comparison of skin stiffness under different negative pressures;

[0031] Figure 7 Schematic diagram of achieving stretchable and foldable variable stiffness skin;

[0032] Figure 8 Schematic diagram of realizing 3D deformable curling envelope for variable stiffness skin;

[0033] Fig. 9 Schematic diagram of a variable stiffness skin that can conform to objects of different contours and have a certain load-bearing capacity.

[0034] In the figure: 1. lower silicone rubber membrane; 2. column; 3. discrete blocking element; 4. vacuum tube; 5. upper silicone rubber membrane; 6. blocking layer. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the described scope.

[0036] like Figure 1-2 As shown, a 3D deformable variable stiffness skin based on laminar blockage mechanism includes a lower silicone rubber membrane 1, a group of columns 2, a group of discrete blocking elements 3, a vacuum tube 4 and an upper silicone rubber membrane 5. A group of columns 2 are provided on the surface of the lower silicone rubber membrane 1, and each column 2 is provided with a plurality of layers of discrete blocking elements 3, wherein the multiple layers of discrete blocking elements 3 constitute a blocking layer 6. One end of the vacuum tube 4 is provided on the lower silicone rubber membrane 1, and the other end thereof is connected to a vacuum pump. The upper silicone rubber membrane 5 is coated and sealed on the lower silicone rubber membrane 1.

[0037] The present invention provides a 3D deformable variable-degree skin based on a laminar blockage mechanism, wherein the discrete blockage element 3 is hexagonal, circular or rectangular, and is made of PET.

[0038] Depend on Figure 3-4 As described above, when under atmospheric pressure (i.e., no negative pressure is applied to the skin), all the blocking layers 6 are discrete and can slide freely against each other, and the whole is soft and stretchable. When under negative pressure (i.e., the skin is evacuated), the silicone mold and the blocking layer 6 are both pressed tightly and have small deformations. The layers are pressed tightly, the friction increases, and the whole becomes hard and has small deformations.

[0039] The present invention also proposes a method for preparing a 3D deformable variable stiffness skin based on a laminar flow blocking mechanism, comprising the following steps:

[0040] 1) According to the preset skin size, a mold 1 for the lower silicone rubber membrane 1 and a mold 2 for the upper silicone rubber membrane 5 are respectively manufactured by laser cutting method, and are used for standby after the manufacturing is completed; the mold 1 and the mold 2 have the same structure and are both transparent molds;

[0041] 2) manufacturing a column 2 and a discrete blocking element 3 for use;

[0042] Specifically, a laser cutting machine is used to cut the PET into a plurality of discrete blocking elements 3; a silicone rubber tube is cut into a plurality of 10 mm long columns 2;

[0043] 3) Pour the two silicone rubbers into a beaker, stir and mix them with a glass rod, and after they are fully mixed, put them into a vacuum drying oven for vacuum treatment until no bubbles emerge in the beaker, and then slowly pour the mixture into the mold 1 and mold 2 prepared in step 1) until the mixture reaches the edge, and then place the two molds on a flat surface for curing. After the curing is completed, the lower silicone rubber film 1 and the upper silicone rubber film 5 are obtained for use;

[0044] The volume ratio of the two silicone rubbers is 1:1; the two silicone rubbers that are fully mixed are placed under a negative pressure of -0.1MPa for 2-3 minutes until no bubbles emerge in the beaker; the materials in mold 1 and mold 2 are cured for 7 hours;

[0045] 4) According to the pre-layout requirements, fix the pillar 2 made in step 2) on the surface of the lower silicone rubber membrane 1 prepared in step 3) with tweezers, then fix the discrete blocking element 3 made in step 2) on the pillar 2, and then seal the top of the pillar 2 with silicone rubber adhesive, and apply adhesive around the outer surface of the pillar 2 to form a ring to prevent the discrete blocking element 3 from falling off;

[0046] 5) After step 4) is completed, a vacuum tube 4 is arranged on the surface of the lower silicone rubber film 1, wherein one end of the vacuum tube 4 is located on 1, and the end is outside the outermost column 2), and then the upper silicone rubber film 5 prepared in step 3) is covered, and the edge is pressed to seal, and the skin to be prepared can be obtained;

[0047] 6) Perform an air tightness test on the skin prepared in step 5).

[0048] Example 1

[0049] The preset skin size is 150 mm × 150 mm, and the size of the effective blocking area is 130 mm × 130 mm.

[0050] 1) According to the preset skin size, a transparent mold 1 for the lower silicone rubber film 1 and a transparent mold 2 for the upper silicone rubber film 5 are respectively made by laser cutting, and a pre-designed draft paper is printed at a 1:1 ratio according to the actual skin size, and is placed under the transparent mold to guide subsequent steps;

[0051] 2) Using a laser cutting machine, the PET is cut into a plurality of hexagonal discrete plugging elements 3; and a silicone rubber tube with a diameter of 2 mm is cut into a plurality of 10 mm long columns 2;

[0052] 3) Pour the two components of silicone rubber Smooth-On's Slow A and B into a beaker in a volume ratio of 1:1, stir clockwise with a glass rod to mix thoroughly. According to experience, 40 g of DS Slow is required to ensure that the film is thin enough and not easy to tear. After stirring, put it into a vacuum drying oven for vacuum treatment, and place it under a negative pressure of -0.1MPa for 2 to 3 minutes until no bubbles emerge in the beaker, and then slowly pour the mixture into transparent mold 1 and transparent mold 2 until it reaches the edge, and then place it on a flat surface to cure for 7 hours to form a lower silicone rubber film 1 and an upper silicone rubber film 2 5;

[0053] 4) According to the pre-layout requirements, fix the manufactured pillar 2 on the surface of the lower silicone rubber film 1 with tweezers, then fix the hexagonal discrete blocking element 3 on the pillar 2, and then seal the top of the pillar 2 with silicone rubber adhesive, and apply adhesive around the outer surface of the pillar 1 to form a ring to prevent the discrete blocking element 3 from falling off;

[0054] 5) A vacuum tube 4 is arranged on the surface of the lower silicone rubber film 1, wherein one end of the vacuum tube 4 is located on the lower silicone rubber film 1, and the end is outside the edgemost column 2, and the other end is connected to a vacuum pump, and then the prepared upper silicone rubber film 5 is covered, and the edge is pressed to seal, and the skin 1 to be prepared can be obtained;

[0055] 6) Perform an airtightness test on the prepared skin. If the skin leaks, fill it with a syringe filled with silicone rubber.

[0056] Example 2

[0057] The preset skin size is 150 mm × 150 mm, and the size of the effective blocking area is 130 mm × 130 mm.

[0058] 1) According to the preset skin size, a transparent mold 1 for the lower silicone rubber film 1 and a transparent mold 2 for the upper silicone rubber film 5 are respectively made by laser cutting, and a pre-designed draft paper is printed at a 1:1 ratio according to the actual skin size, and is placed under the transparent mold to guide subsequent steps;

[0059] 2) Using a laser cutting machine, cut the PET into a plurality of circular discrete blocking elements 3 (the circular blocking element and the hexagon in Example 1 share the same midpoint and are the size of the circumscribed circle of the hexagon); cut the silicone rubber tube with a diameter of 2 mm into a plurality of 10 mm long columns 2;

[0060] 3) Pour the two components of silicone rubber Smooth-On's Slow A and B into a beaker in a volume ratio of 1:1, stir clockwise with a glass rod to mix thoroughly. According to experience, 40 g of DS Slow is required to ensure that the film is thin enough and not easy to tear. After stirring, put it into a vacuum drying oven for vacuum treatment, and place it under a negative pressure of -0.1MPa for 2 to 3 minutes until no bubbles emerge in the beaker, and then slowly pour the mixture into transparent mold 1 and transparent mold 2 until it reaches the edge, and then place it on a flat surface to cure for 7 hours to form a lower silicone rubber film 1 and an upper silicone rubber film 2 5;

[0061] 4) According to the pre-layout requirements, fix the manufactured pillar 2 on the surface of the lower silicone rubber film 1 with tweezers, then fix the hexagonal discrete blocking element 3 on the pillar 2, and then seal the top of the pillar 2 with silicone rubber adhesive, and apply adhesive around the outer surface of the pillar 2 to form a ring to prevent the discrete blocking element 3 from falling off;

[0062] 5) A vacuum tube 4 is arranged on the surface of the lower silicone rubber film 1, wherein one end of the vacuum tube 4 is located on the lower silicone rubber film 1, and the end is outside the edgemost column 2, and the other end is connected to a vacuum pump, and then the prepared upper silicone rubber film 5 is covered, and the edge is pressed to seal, and the second skin to be prepared can be obtained;

[0063] 6) Perform an airtightness test on the prepared skin 2. If the skin leaks, fill it with a syringe filled with silicone rubber.

[0064] Example 3

[0065] The preset skin size is 150 mm × 150 mm, and the size of the effective blocking area is 130 mm × 130 mm.

[0066] 1) According to the preset skin size, a transparent mold 1 for the lower silicone rubber film 1 and a transparent mold 2 for the upper silicone rubber film 5 are respectively made by laser cutting, and a pre-designed draft paper is printed at a 1:1 ratio according to the actual skin size, and is placed under the transparent mold to guide subsequent steps;

[0067] 2) Using a laser cutting machine, cut the PET into a plurality of rectangular discrete blocking elements 3 (the rectangular blocking element and the hexagon in Example 1 share the same midpoint, and the diagonal is the diameter of the circumscribed circle of the hexagon); cut the silicone rubber tube with a diameter of 2 mm into a plurality of 10 mm long columns 2;

[0068] 3) Pour the two components of silicone rubber Smooth-On's Slow A and B into a beaker in a volume ratio of 1:1, stir clockwise with a glass rod to mix thoroughly. According to experience, 40 g of DS Slow is required to ensure that the film is thin enough and not easy to tear. After stirring, put it into a vacuum drying oven for vacuum treatment, and place it under a negative pressure of -0.1MPa for 2 to 3 minutes until no bubbles emerge in the beaker, and then slowly pour the mixture into transparent mold 1 and transparent mold 2 until it reaches the edge, and then place it on a flat surface to cure for 7 hours to form a lower silicone rubber film 1 and an upper silicone rubber film 2 5;

[0069] 4) According to the pre-layout requirements, fix the manufactured pillar 2 on the surface of the lower silicone rubber film 1 with tweezers, then fix the hexagonal discrete blocking element 3 on the pillar 2, and then seal the top of the pillar 2 with silicone rubber adhesive, and apply adhesive around the outer surface of the pillar 2 to form a ring to prevent the discrete blocking element 3 from falling off;

[0070] 5) A vacuum tube 4 is arranged on the surface of the lower silicone rubber film 1, wherein one end of the vacuum tube 4 is located on the lower silicone rubber film 1, and the end is outside the edgemost column 2, and the other end is connected to a vacuum pump, and then the prepared upper silicone rubber film 5 is covered, and the edge is pressed to seal, and the skin 3 to be prepared can be obtained;

[0071] 6) Perform an airtightness test on the prepared skin. If the skin leaks, fill it with a syringe filled with silicone rubber.

[0072] The skins 1 to 3 prepared in experiments 1 to 3 passed the airtightness test. Figure 5 It can be seen that the blocking element adopts hexagonal PET. Compared with circular and rectangular blocking elements, the hexagonal shape has high space utilization and is similar to a honeycomb structure, so that the overlapping area between blocking layers is the largest and the skin stiffness change effect is the best.

[0073] Different negative pressures are applied to the skin. Figure 6 It can be seen that the greater the negative pressure, the better the stiffness effect, until the effect is stable at -80 KPa. The present invention can adjust the overall stiffness of the skin by controlling the application of negative pressure.

[0074] like Figure 7 As shown, the skin has a certain flexibility under atmospheric pressure and can be reversibly stretched, bent and folded in multiple directions; Figure 8 As shown, after the given shape is activated, the stiffness of the skin 1 increases, the skin 1 can resist the deformation force and maintain the given 3D shape, and can be used as some functional tools, such as a temporary liquid container. The skin 1 with an effective area of ​​130×130mm can envelop a sphere with a maximum diameter of 80mm; and as shown Fig. 9 As shown, the skin can adapt to objects with different contours, and after activation, its contour remains unchanged and has a certain load-bearing capacity, which reflects good conformability and rigidity.

Claims

1. A 3D deformable variable stiffness skin based on laminar blockage mechanism, characterized in that The invention comprises a lower silicone rubber membrane (1), a group of columns (2), a group of discrete blocking elements (3), a vacuum tube (4) and an upper silicone rubber membrane (5), wherein a group of columns (2) is provided on the surface of the lower silicone rubber membrane (1), each column (2) is provided with a plurality of layers of discrete blocking elements (3), wherein the plurality of layers of discrete blocking elements (3) constitute a blocking layer (6), one end of the vacuum tube (4) is provided on the lower silicone rubber membrane (1), and the other end thereof is connected to a vacuum pump, and the upper silicone rubber membrane (5) is covered and sealed on the lower silicone rubber membrane (1).

2. A 3D deformable variable stiffness skin based on laminar blockage mechanism according to claim 1, characterized in that The discrete blocking element (3) is hexagonal, circular or rectangular in shape and is made of PET.

3. A method for preparing a 3D deformable variable stiffness skin based on laminar blockage mechanism as claimed in claim 1, characterized in that The steps include: 1) According to the preset skin size, a mold 1 for the lower silicone rubber membrane (1) and a mold 2 for the upper silicone rubber membrane (5) are respectively manufactured by laser cutting method, and are set aside after the manufacturing is completed; 2) manufacturing the column (2) and the discrete blocking element (3) for use; 3) Pour the two silicone rubbers into a beaker and stir with a glass rod to mix. After being fully mixed, place the mixture in a vacuum drying oven for vacuum treatment until no bubbles emerge in the beaker. Then slowly pour the mixture into the mold 1 and mold 2 prepared in step 1) until the mixture reaches the edge. Then place the two molds on a flat surface for curing. After the curing is completed, a lower silicone rubber film (1) and an upper silicone rubber film (5) are obtained for use. 4) According to the pre-layout requirements, the pillar (2) manufactured in step 2) is fixed on the surface of the lower silicone rubber membrane (1) prepared in step 3) with tweezers, and then the discrete blocking element (3) manufactured in step 2) is fixed on the pillar (2), and then the top of the pillar (2) is sealed with a silicone rubber adhesive; 5) After step 4) is completed, a vacuum tube (4) is arranged on the surface of the lower silicone rubber film (1), and then the upper silicone rubber film (5) prepared in step 3) is covered, and the edges are pressed to seal, so that the skin to be prepared can be obtained; 6) Perform an air tightness test on the skin prepared in step 5).

4. The preparation method according to claim 3, characterized in that 1) In the steps, mold 1 and mold 2 have the same structure and are both transparent molds.

5. The preparation method according to claim 3, characterized in that The specific operation of step 2) is as follows: use a laser cutting machine to cut the PET into a number of discrete blocking elements (3); cut the silicone rubber tube into a number of 10 mm long columns (2).

6. The preparation method according to claim 3, characterized in that 3) The volume ratio of the two silicone rubbers in the step is 1:1; the two silicone rubbers that are fully mixed are placed under a negative pressure of -0.1 MPa for 2-3 minutes until no bubbles emerge in the beaker; the materials in mold 1 and mold 2 are cured for 7 hours.

7. The preparation method according to claim 3, characterized in that In step 4), adhesive is applied around the outer surface of the column (2) to form a ring.

8. The preparation method according to claim 3, characterized in that In step 5), one end of the vacuum tube (4) is located on the lower silicone rubber membrane (1), and the end is located outside the outermost column (2).

9. The preparation method according to claim 3, characterized in that 6) If the skin leaks during the step, fill it with a syringe filled with silicone rubber.

Images