Stiffness-variable soft gripper and stiffness-variable soft gripper

Abstract

The application discloses a variable-rigidity soft claw and a variable-rigidity soft gripper, and relates to the technical field of soft grippers. The variable-rigidity soft claw comprises a driving structure, a variable-rigidity layer and a plurality of electro-rheological liquid elastic balls, the variable-rigidity layer is fixedly connected to the driving structure, the variable-rigidity layer is made of soft material and can be deformed, the variable-rigidity layer has a sealed variable-rigidity cavity, each electro-rheological liquid elastic ball is fixedly connected in the variable-rigidity cavity, each electro-rheological liquid elastic ball is used for being connected with an external power supply, and the driving structure can drive the variable-rigidity layer to contact or separate from a grasped object. The variable-rigidity soft claw and the variable-rigidity soft gripper are more flexible and have a wider application range.

Description

Technical Field

[0001] The present invention relates to the technical field of soft grippers, and in particular to a variable-rigidity soft claw and a variable-rigidity soft gripper. Background Art

[0002] Current mechanical grippers are usually made of rigid materials, have a fixed shape, and are relatively inflexible. They can usually only adapt to objects of specific shapes and sizes. When grasping fragile or soft objects, they can easily cause damage to the grasped objects. In response to the above problems, some mechanical grippers with variable stiffness functions have gradually emerged, which change the stiffness of the gripper to make the gripper and the grasped object fit better. However, the flexibility of current mechanical grippers with variable stiffness functions is still not ideal, and their applicability is poor. Therefore, there is an urgent need for a variable stiffness soft claw and variable stiffness soft gripper with greater flexibility and a wider range of applications. Summary of the Invention

[0003] The purpose of the present invention is to provide a variable-rigidity soft claw and a variable-rigidity soft gripper to solve the problems existing in the above-mentioned prior art, with greater flexibility and a wider range of applications.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a variable-stiffness soft claw, comprising: a drive structure, a variable-stiffness layer, and a plurality of electrorheological fluid elastic balls. The variable-stiffness layer is fixedly connected to the drive structure, the variable-stiffness layer is made of a soft material and is deformable, the variable-stiffness layer has a sealed variable-stiffness cavity, and each electrorheological fluid elastic ball is fixedly connected to the variable-stiffness cavity. Each electrorheological fluid elastic ball is used to connect to an external power supply. The drive structure can drive the variable-stiffness layer to contact or separate from the grasped object.

[0006] In some embodiments, an elastic membrane is further included, and a first opening connecting the variable stiffness cavity and the outside world is provided on one side of the variable stiffness layer. The elastic membrane is fixedly connected to the variable stiffness layer and covers the first opening. The variable stiffness layer is also provided with a variable stiffness air port connecting the variable stiffness cavity and the outside world.

[0007] In some embodiments, the driving structure is a pneumatic deformation layer, which is capable of deformation and has a sealed deformation cavity therein. The pneumatic deformation layer is provided with a deformation air port connecting the deformation cavity and the outside world. Inflating or deflating the deformation cavity can cause the pneumatic deformation layer to bend or straighten.

[0008] In some embodiments, a second opening communicating with the deformation cavity and the outside is provided on one side of the pneumatic deformation layer, and a circumferential edge of the second opening is fixedly connected to the elastic membrane.

[0009] In some embodiments, flexible electrodes are fixedly connected to both sides of the electrorheological fluid elastic ball, and the two flexible electrodes are respectively used to connect to the positive electrode and the negative electrode of an external power supply.

[0010] In some embodiments, the variable stiffness layer and the pneumatic deformation layer are both made of fabric.

[0011] In some embodiments, two variable stiffness air ports are provided, and the two variable stiffness air ports are respectively located at two ends of the variable stiffness layer.

[0012] In some embodiments, the elastic membrane is made of silicone.

[0013] The present invention also provides a variable-rigidity soft gripper, comprising a base and the above-mentioned variable-rigidity soft claws, wherein each of the variable-rigidity soft claws is fixedly connected to one side of the base.

[0014] In some embodiments, the variable-rigidity soft claws are sequentially arranged at equal intervals along a circumferential trajectory.

[0015] Compared with the prior art, the present invention has achieved the following technical effects:

[0016] The variable-rigidity soft claw and the electrorheological fluid elastic ball provided by the present invention can quickly respond to changes in the electric field, thereby changing their own stiffness. At the same time, by passing currents of different magnitudes into different electrorheological fluid elastic balls, different positions of the variable-rigidity soft claw can have different stiffnesses, thereby adapting to different grasped objects, thereby improving the flexibility and applicability of the variable-rigidity soft claw.

[0017] Furthermore, when the stiffness of the variable stiffness layer needs to be changed, the air pump can be connected to the variable stiffness air port, and the contact area between the electrorheological fluid elastic balls and between the electrorheological fluid elastic balls and the inner wall of the variable stiffness cavity can be changed by introducing or releasing gas into the variable stiffness cavity, thereby changing the stiffness of the variable stiffness layer and making the variable stiffness layer more flexible.

[0018] Furthermore, by inflating the pneumatic deformation layer, the elastic membrane can also squeeze the electrorheological fluid elastic balls, increasing the contact area between the electrorheological fluid elastic balls and between the electrorheological fluid elastic balls and the inner wall of the variable stiffness cavity, thereby increasing the stiffness of the variable stiffness layer and further improving the flexibility of the variable stiffness layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A three-dimensional structural diagram of a variable-rigidity soft claw in some embodiments of the present invention;

[0021] Figure 2 A cross-sectional view of a variable-rigidity soft claw in some embodiments of the present invention;

[0022] Figure 3 A three-dimensional structural diagram of a variable stiffness soft gripper in some embodiments of the present invention;

[0023] Figure 4 A three-dimensional structural diagram of a first mold in some embodiments of the present invention;

[0024] Figure 5 A three-dimensional structural diagram of a second mold in some embodiments of the present invention;

[0025] In the figure: 1. Variable stiffness layer; 2. Electrorheological fluid elastic ball; 3. Flexible electrode; 4. Pneumatic deformation layer; 5. Variable stiffness air port; 6. Deformation air port; 7. Elastic membrane; 8. Base; 9-first mold; 10-second mold. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] The purpose of the present invention is to provide a variable stiffness soft claw and a variable stiffness soft gripper to solve the problems existing in the above-mentioned prior art, with greater flexibility and a wider range of applications.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Example 1

[0030] This embodiment provides a variable stiffness soft claw, such as Figure 1-2 As shown, it includes: a driving structure, a variable stiffness layer 1 and multiple electrorheological fluid elastic balls 2. The variable stiffness layer 1 is fixedly connected to the driving structure. The variable stiffness layer 1 is a soft material and can be deformed. The variable stiffness layer 1 has a sealed variable stiffness cavity. Each electrorheological fluid elastic ball 2 is fixedly connected in the variable stiffness cavity. Each electrorheological fluid elastic ball 2 is used to connect to an external power supply. The driving structure can drive the variable stiffness layer 1 to contact or separate from the grasped object.

[0031] The variable-stiffness soft claw in this embodiment can be controlled by a drive structure to bring the variable-stiffness layer 1 into contact with or separate from the object being grasped, thereby grasping or releasing the object. When grasping an object, electricity can be applied to the electrorheological fluid elastic ball 2. When a large current flows through the electrorheological fluid elastic ball 2, the conductive particles in the electrorheological fluid rearrange themselves under the action of the electric field, increasing the stiffness of the electrorheological fluid and, in turn, the stiffness of the electrorheological fluid elastic ball 2. When a small current flows through the electrorheological fluid elastic ball 2, the stiffness of the electrorheological fluid elastic ball 2 decreases. Furthermore, different currents can be applied to different electrorheological fluid elastic balls 2 to impart different stiffnesses to different locations of the variable-stiffness layer 1, thereby achieving a better fit with the object being grasped. The electrorheological fluid elastic ball 2 can quickly respond to changes in the electric field, thereby changing its own stiffness. At the same time, by passing currents of different magnitudes into different electrorheological fluid elastic balls 2, different positions of the variable-stiffness soft claw can have different stiffnesses, thereby adapting to more objects to be grasped, improving the flexibility of the variable-stiffness soft claw, and expanding its scope of application.

[0032] In one embodiment of this embodiment, the variable stiffness soft claw in this embodiment also includes an elastic membrane 7. A first opening connecting the variable stiffness cavity and the outside world is provided on one side of the variable stiffness layer 1. The elastic membrane 7 is fixedly connected to the variable stiffness layer 1 and covers the first opening. The variable stiffness layer 1 is also provided with a variable stiffness air port 5 connecting the variable stiffness cavity and the outside world. When the stiffness of the variable stiffness layer 1 needs to be changed, the air pump can be connected to the variable stiffness air port 5, and the air in the variable stiffness layer 1 can be extracted by the air pump, so that the elastic membrane 7 squeezes the electrorheological fluid elastic ball 2, and the contact area between the inner wall of the variable stiffness layer 1 and the electrorheological fluid elastic ball 2, and between the electrorheological fluid elastic balls 2, increases, and the stiffness of the variable stiffness layer 1 increases; when the air pump is disconnected, the gas will enter the variable stiffness cavity due to the pressure difference between the variable stiffness cavity and the outside world and cause the elastic membrane 7 to rebound, and the contact area between the inner wall of the variable stiffness layer 1 and the electrorheological fluid elastic ball 2, and between the electrorheological fluid elastic balls 2 decreases, and the stiffness of the variable stiffness layer 1 decreases. In this way, the variable stiffness layer 1 and the electrorheological fluid elastic ball 2 can jointly change the stiffness of the variable stiffness layer 1, making the variable stiffness layer 1 more flexible.

[0033] In one embodiment of this invention, the driving structure is a pneumatically deformable layer 4, which is capable of deformation and contains a sealed deformation chamber. Deformation ports 6 are provided on the layer 4, connecting the deformation chamber to the outside world. Inflating or deflating the deformation chamber causes the pneumatically deformable layer 4 to bend or straighten. Inflating the deformation chamber through the deformation ports 6 causes the pneumatically deformable layer 4 to bend and bring the variable-stiffness layer 1 into contact with the object being grasped. Deflating the deformation chamber through the deformation ports 6 causes the pneumatically deformable layer 4 to straighten and move the variable-stiffness layer 1 away from the object being grasped.

[0034] It should be noted that in addition to the pneumatic deformation layer 4, electronic equipment such as a linear moving module and a robotic arm can also be used to replace the pneumatic deformation layer 4. For example, the variable stiffness layer 1 can be fixedly connected to the free end of the linear moving module, and then the free end of the linear moving module is used to control the position of the variable stiffness layer 1 so that the variable stiffness layer 1 contacts or separates from the object being grasped.

[0035] In one embodiment of this invention, a second opening is provided on one side of the pneumatically deformable layer 4, connecting the deformation chamber with the outside world. The circumferential edge of the second opening is fixedly connected to the elastic membrane 7. By inflating the pneumatically deformable layer 4, the elastic membrane 7 can also squeeze the ERF elastic balls 2, increasing the contact area between the ERF elastic balls 2 and between the ERF elastic balls 2 and the inner wall of the variable stiffness layer 1, thereby increasing the stiffness of the variable stiffness layer 1 and further enhancing its flexibility.

[0036] To facilitate connection between the electrorheological fluid elastic ball 2 and an external power source, in this embodiment, flexible electrodes 3 are fixedly connected to both sides of the electrorheological fluid elastic ball 2. The two flexible electrodes 3 are respectively used to connect to the positive and negative poles of the external power source. Each electrorheological fluid elastic ball 2 has a flexible electrode fixedly connected to both sides.

[0037] In one embodiment of this invention, both the variable stiffness layer 1 and the pneumatically deformable layer 4 are made of fabric. Fabric is a lightweight and flexible material that reduces the overall weight of the variable stiffness soft claw. It also possesses excellent tensile strength, wear resistance, and a high load-bearing capacity. It also offers good waterproof and dustproof properties, making it suitable for a variety of working environments.

[0038] In order to facilitate the inflation or deflation of air into the variable stiffness layer 1 , in one embodiment of the present invention, two variable stiffness air ports 5 are provided, and the two variable stiffness air ports 5 are respectively located at the two ends of the variable stiffness layer 1 .

[0039] In one embodiment of the present invention, the elastic membrane 7 is made of silicone material. Silicone material has good elasticity and airtightness, and can deform and squeeze the electrorheological fluid elastic ball 2 under the pressure of the gas.

[0040] Example 2

[0041] This embodiment provides a variable stiffness soft gripper, such as Figure 3 As shown, it includes a base 8 and multiple variable-rigidity soft claws in embodiment 1, and each variable-rigidity soft claw is fixedly connected to one side of the base 8.

[0042] In the variable stiffness soft gripper of this embodiment, the electrorheological fluid elastic ball 2 can quickly respond to changes in the electric field, thereby changing its own stiffness. The stiffness of the electrorheological fluid elastic ball 2 is controlled by current. By passing currents of different sizes into different electrorheological fluid elastic balls 2, the variable stiffness soft gripper can adapt to more grasped objects, thereby improving the flexibility of the variable stiffness soft gripper and expanding the scope of application of the variable stiffness soft gripper.

[0043] In order to make the force exerted by the variable stiffness soft gripper on the grasped object more uniform, in one implementation of this embodiment, the variable stiffness soft claws are arranged in sequence at equal intervals along a circular trajectory.

[0044] Example 3

[0045] This embodiment provides a method for manufacturing a variable-rigidity soft claw in some implementations of Example 1:

[0046] The first mold 9 is printed using 3D printing technology. The material of the first mold 9 is water-soluble polyvinyl alcohol (PVA);

[0047] The first mold 9 is used to preset the outer side corresponding to the elastic film as the first side, and the elastic film is covered on the first side. Then, fabrics are covered on all other outer sides of the first mold 9 except the first side. The adjacent fabrics and the fabric and the elastic film are welded together using an electric soldering iron. Then, 60°C water is poured into the first mold 9 to dissolve the first mold.

[0048] After the first mold 9 is dissolved, the fabric is air-dried, and then the unsealed joints between the fabrics are supplemented with welding using an electric soldering iron, and the excess fabric is trimmed with scissors to form an aerodynamic deformation layer. Finally, the airtightness of the aerodynamic deformation layer is tested;

[0049] A second mold 10 is made, and the fabric is placed in the second mold 10, close to the inner side of the second mold 10, and the fabric is fixed into the shape of the second mold 10 with silicone. Then, multiple electrorheological fluid elastic balls are placed in the fabric, and the second mold 10 is removed to form a variable stiffness layer. The variable stiffness layer and the elastic membrane are connected with silicone (or hot melt connection is used) to form a variable stiffness soft body.

[0050] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A variable stiffness soft claw, characterized by: include: A driving structure, a variable stiffness layer and a plurality of electrorheological fluid elastic balls, wherein the variable stiffness layer is fixedly connected to the driving structure, the variable stiffness layer is a soft material and can be deformed, the variable stiffness layer has a sealed variable stiffness cavity, each electrorheological fluid elastic ball is fixedly connected in the variable stiffness cavity, each electrorheological fluid elastic ball is used to connect to an external power supply, and the driving structure can drive the variable stiffness layer to contact or separate from the grasped object; and further comprising an elastic membrane, wherein one side of the variable stiffness layer is provided with a first opening connecting the variable stiffness cavity and the outside world, and the elastic membrane is fixedly connected to the The variable stiffness layer is on and covers the first opening, and the variable stiffness layer is also provided with a variable stiffness air port connecting the variable stiffness cavity and the outside world; the driving structure is a pneumatic deformation layer, the pneumatic deformation layer can be deformed, and the pneumatic deformation layer has a sealed deformation cavity, and the pneumatic deformation layer is provided with a deformation air port connecting the deformation cavity and the outside world, and inflating or deflating the deformation cavity can make the pneumatic deformation layer bend or straighten; a second opening connecting the deformation cavity and the outside world is provided on one side of the pneumatic deformation layer, and the circumferential edge of the second opening is fixedly connected to the elastic membrane.

2. The variable stiffness soft claw according to claim 1, characterized in that: Flexible electrodes are fixedly connected to both sides of the electrorheological fluid elastic ball, and the two flexible electrodes are used to connect to the positive electrode and the negative electrode of the external power supply respectively.

3. The variable stiffness soft claw according to claim 1, characterized in that: The variable stiffness layer and the pneumatic deformation layer are both made of fabric.

4. The variable stiffness soft claw according to claim 1, characterized in that: There are two variable stiffness air ports, and the two variable stiffness air ports are respectively located at two ends of the variable stiffness layer.

5. The variable stiffness soft claw according to claim 1, characterized in that: The elastic membrane is made of silicone material.

6. A variable stiffness soft gripper, characterized by: The invention comprises a base and a plurality of variable-rigidity soft claws according to any one of claims 1 to 5, wherein each of the variable-rigidity soft claws is fixedly connected to one side of the base.

7. The variable stiffness soft gripper according to claim 6, characterized in that: The variable-rigidity soft claws are arranged in sequence at equal intervals along a circumferential track.

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