Gripper and robot

Abstract

The invention discloses a gripper, and relates to the technical field of robot grippers, the gripper mainly comprises a flexible fabric gripper main body and a variable stiffness layer, the flexible fabric gripper main body is formed by connecting multiple sections of fabrics, the flexible fabric gripper main body is connected with a driving device, and the driving device can drive the flexible fabric gripper main body to grab and put down an object; the variable-rigidity layer covers the non-grabbing face of the flexible fabric gripper body, the rigidity of the variable-rigidity layer can be changed, and deformation of the flexible fabric gripper body can be resisted. The invention further discloses a robot which comprises the gripper. According to the invention, an object is not damaged under the condition that the gripping force is enough.

Description

Technical Field

[0001] The present invention relates to the technical field of robot grippers, in particular to grippers and robots. Background Art

[0002] Traditional industrial robot grippers are made of rigid hard materials. Their extremely high rigidity makes them prone to rigid collisions during movement, which limits their application scenarios and easily causes damage when grasping brittle materials. Although some grippers currently have good flexibility, their fingers have low stiffness and cannot withstand high pressures. The weight range of objects that can be effectively grasped is limited, and only objects with lighter weights can be effectively grasped. An existing multi-finger soft gripper is provided with a variable stiffness layer and a pneumatic drive layer. The variable stiffness layer is arranged on the inner side of the pneumatic drive layer. The pneumatic drive layer is used to inflate the variable stiffness layer to bend to grasp objects. However, since the variable stiffness layer is in direct contact with the object, when the object is heavy and made of brittle material, a large grasping force may be required. The texture of the variable stiffness layer becomes harder, and there is a risk of damaging the object. Therefore, there is an urgent need for a gripper and a robot to change the above technical problems. Summary of the invention

[0003] The purpose of the present invention is to provide a gripper and a robot to solve the problems existing in the above-mentioned prior art, and to ensure that the gripping force is sufficient without damaging the object itself.

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

[0005] The present invention provides a gripper, comprising

[0006] A flexible fabric gripper body, wherein the flexible fabric gripper body is formed by connecting a plurality of fabric sections, and the flexible fabric gripper body is connected to a driving device, and the driving device can drive the flexible fabric gripper body to grab and put down an object;

[0007] A variable stiffness layer is covered on the non-gripping surface of the flexible fabric gripper body, and the stiffness of the variable stiffness layer can be changed.

[0008] Preferably, a closed cavity is provided inside the flexible fabric gripper body, and the driving device is an air pump for filling the closed cavity with gas.

[0009] Preferably, the variable stiffness layer comprises an electrorheological elastomer and an electric field generating device, wherein the electrorheological elastomer is disposed in the electric field generating device, and the electric field generating device can generate an electric field, and the electric field can cause the stiffness of the electrorheological elastomer to change.

[0010] Preferably, the electric field generating device comprises a first flexible electrode layer and a second flexible electrode layer, the first flexible electrode layer and the second flexible electrode layer are respectively adhered to the two sides of the electrorheological elastomer, and the first flexible electrode layer is adhered to the non-grasping surface of the flexible fabric gripper body, and the first flexible electrode layer and the second flexible electrode layer can be connected to a power source to generate an electric field.

[0011] Preferably, it further comprises a first lead wire and a second lead wire, wherein the first lead wire is connected to the first flexible electrode layer, the second lead wire is connected to the second flexible electrode layer, and the first lead wire and the second lead wire are used to connect a power source.

[0012] Preferably, the first lead wire and the second lead wire are both copper wires.

[0013] Preferably, it also includes a flexible silicone shell, which is used to accommodate and seal the electrorheological elastomer.

[0014] Preferably, it also includes a first flexible substrate layer and a second flexible substrate layer, wherein the two sides of the first flexible substrate layer are respectively connected to the flexible fabric gripper body and the first flexible electrode layer, and one side of the second flexible substrate layer is connected to the silicone shell and the other side is in contact with the air.

[0015] Preferably, the multiple sections of fabric can be bent or twisted. When each section of fabric is square, the multiple sections of fabric can be bent and deformed; when each section of fabric is a non-square block, the multiple sections of fabric can be twisted and deformed.

[0016] The present invention also provides a robot comprising the gripper as described above.

[0017] Compared with the prior art, the present invention has achieved the following technical effects:

[0018] The flexible fabric gripper body of the present invention is formed by connecting multiple sections of fabric, and the flexible fabric gripper body is connected to a driving device, which can drive the flexible fabric gripper body to grab and put down objects. The variable stiffness layer covers the non-grabbing surface of the flexible fabric gripper body, and the stiffness of the variable stiffness layer can change. The flexible fabric gripper body is formed by connecting multiple sections of fabric, so that it can adaptively fit according to the outer contour of the grasped object. Whether it is an object of regular shape or an object of irregular shape and uneven surface, it can be well wrapped and grasped, greatly expanding the range of graspable objects. The fabric material itself is relatively soft. When grasping some fragile and fragile objects, it can avoid scratching or squeezing damage to the surface of the object, realize gentle and stable grasping operation, and ensure the integrity of the grasped object. Moreover, compared with silicone materials, the fabric is light in weight, has good tensile strength and wear resistance, is not easy to deform when bearing, and can have a higher load-bearing capacity. The variable stiffness layer covers the non-grasping object surface of the flexible fabric gripper body. When the flexible fabric gripper body is deformed under force, the stiffness of the variable stiffness layer changes, which can resist its excessive deformation and maintain the relative stability of the entire gripper structure during the grasping process, ensuring that each grasping action can reliably grasp the object, prevent the object from accidentally slipping, and improve the gripping force. 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 drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0020] Figure 1 Schematic diagram of the three-dimensional structure of the gripper (bending and deforming) in some embodiments of the present invention;

[0021] Figure 2 Schematic diagram of the sandwich structure of the gripper (bending deformation) in some embodiments of the present invention;

[0022] Figure 3 A front view of a gripper (bent and deformed) in some embodiments of the present invention;

[0023] Figure 4 Schematic diagram of a mold of a gripper (bending deformation) in some embodiments of the present invention;

[0024] Figure 5 Schematic diagram of the three-dimensional structure of the gripper (twisted and deformed) in some embodiments of the present invention;

[0025] Figure 6 Schematic diagram of the sandwich structure of the gripper (twisted deformation) in some embodiments of the present invention;

[0026] Figure 7 This is a front view of the gripper (distorted) in some embodiments of the present invention;

[0027] Figure 8 A side view of a gripper (distorted) in some embodiments of the present invention;

[0028] Fig. 9 Schematic diagram of a mold of a gripper (distorted) in some embodiments of the present invention;

[0029] Fig.10 An exploded view of a gripper in some embodiments of the present invention;

[0030] Fig.11 Exploded view of the gripper interlayer in some embodiments of the present invention.

[0031] In the figure: 100-flexible fabric gripper body; 1-air pressure input port; 2-fabric air pressure drive layer; 3-first flexible electrode layer; 4-variable stiffness layer; 41-flexible silicone shell; 5-second flexible electrode layer; 6-first flexible base layer; 7-second flexible base layer; 8-first lead wire; 9-second lead wire. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0033] The purpose of the present invention is to provide a gripper and a robot to solve the problems existing in the prior art and to ensure that the gripping force is sufficient without damaging the object itself.

[0034] 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.

[0035] Embodiment 1

[0036] like Figure 1-Figure 11As shown, the present invention provides a gripper, comprising a flexible fabric gripper body 100 and a variable stiffness layer 4, wherein the flexible fabric gripper body 100 is formed by connecting multiple sections of fabric, and the flexible fabric gripper body 100 is connected to a driving device, which can drive the flexible fabric gripper body 100 to grab and put down an object; the variable stiffness layer 4 covers the non-grabbing surface of the flexible fabric gripper body 100, and the stiffness of the variable stiffness layer 4 can change, and the variable stiffness layer 4 can constrain the deformation of the flexible fabric gripper body 100. The flexible fabric gripper body 100 is formed by connecting multiple sections of fabric, so that it can be adaptively fitted according to the outer contour of the object to be grabbed. Whether it is an object of regular shape or an object of irregular shape and uneven surface, it can be wrapped and grasped well, greatly expanding the range of objects that can be grasped. The fabric material itself is relatively soft. When grasping some fragile and fragile objects, it can avoid scratching or squeezing the surface of the object, achieve a gentle and stable grasping operation, and ensure the integrity of the grasped object. Moreover, compared with silicone materials, the fabric is lighter in weight, has good tensile strength and wear resistance, is not easy to deform when bearing, and can have a higher load-bearing capacity. The variable stiffness layer 4 covers the non-grasping object surface of the flexible fabric gripper body 100. When the flexible fabric gripper body 100 is deformed under force, the variable stiffness layer 4 can play a role in resisting its excessive deformation, maintaining the relative stability of the entire gripper structure during the grasping process, ensuring that each grasping action can reliably grasp the object, prevent the object from accidentally slipping, and improve the gripping force.

[0037] As a preferred embodiment, the flexible fabric gripper body is manufactured by an integral molding method.

[0038] In some embodiments, a closed cavity is provided inside the flexible fabric gripper body 100, and the driving device is an air pump for filling the closed cavity with gas. By adjusting the pressure and flow of the gas, the gripper can grasp the object with appropriate force according to the shape, weight, material and other characteristics of the object. And due to the compressibility of the gas, when the flexible fabric gripper body 100 contacts an irregularly shaped object, the gas in the closed cavity can be adaptively adjusted according to the contour of the object. Compared with traditional rigid grippers, the flexible fabric gripper body 100 driven by an air pump has smoother movements. During the grasping process, the gradual filling of the gas enables the gripper to slowly and steadily wrap the object, reducing the impact on the object and protecting the grasped object to a certain extent.

[0039] It should be noted that there may be a hydraulic drive system that drives the flexible fabric gripper body 100 to grip. The hydraulic drive system delivers hydraulic oil to the closed chamber inside the flexible fabric gripper body 100 through a hydraulic pump. When the hydraulic oil enters the chamber, the pressure in the chamber increases, causing the fabric gripper to expand and achieve a gripping action. However, the hydraulic drive system is relatively complex and requires special hydraulic pumps, hydraulic cylinders, hydraulic valves and other components. The cost is high and it is not easy to implement. In addition, the hydraulic oil may leak, causing pollution and damage to the environment and equipment.

[0040] In some embodiments, the variable stiffness layer 4 includes an electrorheological elastomer and an electric field manufacturing device. The electrorheological elastomer is arranged in the electric field manufacturing device. The electric field manufacturing device can generate an electric field. The electric field can change the stiffness of the electrorheological elastomer, so that the variable stiffness layer 4 can adjust the stiffness in real time according to the current working state of the flexible fabric gripper body 100. When grasping small, light and regularly shaped objects, the electric field can be adjusted to make the electrorheological elastomer in a lower stiffness state, so that the flexible fabric gripper body 100 can fit the object more flexibly for grasping; and when grasping large and heavy objects, the stiffness of the electrorheological elastomer is increased by enhancing the electric field, providing stronger support for the gripper, preventing excessive deformation, and thus improving the stability of grasping. Moreover, the response speed of the electrorheological elastomer to the electric field is usually fast. When the electric field manufacturing device generates an electric field change, the electrorheological elastomer can change its stiffness in a shorter time, and it is a reversible change and can be reused.

[0041] It should be noted that the variable stiffness layer 4 may also be made of magnetorheological elastomer, and the magnetic field manufacturing device used accordingly can also meet the stiffness change requirement of the variable stiffness layer 4 .

[0042] In some embodiments, the electric field manufacturing device includes a first flexible electrode layer 3 and a second flexible electrode layer 5, the first flexible electrode layer 3 and the second flexible electrode layer 5 are respectively attached to the two sides of the electrorheological elastomer, and the first flexible electrode layer 3 is attached to the non-grasping surface of the flexible fabric gripper body 100, and the first flexible electrode layer 3 and the second flexible electrode layer 5 can be connected to a power source to generate an electric field. When the first flexible electrode layer 3 and the second flexible electrode layer 5 are connected to a power source to generate an electric field, since they are attached to the two sides of the electrorheological elastomer, a relatively uniform electric field can be formed inside the electrorheological elastomer. The uniform electric field can make the stiffness changes of various parts of the electrorheological elastomer more consistent, so that the variable stiffness layer 4 can play a role more stably and evenly, avoiding the performance of the gripper being affected by excessive differences in local stiffness changes.

[0043] In some embodiments, the gripper further includes a first lead wire 8 and a second lead wire 9, the first lead wire 8 is connected to the first flexible electrode layer 3, the second lead wire 9 is connected to the second flexible electrode layer 5, and the first lead wire 8 and the second lead wire 9 are used to connect a power source. The first lead wire 8 and the second lead wire 9 provide two independent power control channels for the electric field manufacturing device, which can control the electric potential of the first flexible electrode layer 3 and the second flexible electrode layer 5 respectively, and apply different voltages to the two electrode layers, thereby generating an electric field with a specific direction and intensity distribution to meet different stiffness adjustment requirements.

[0044] In some embodiments, the first lead wire 8 and the second lead wire 9 are both copper wires. Using copper wire as the first lead wire 8 and the second lead wire 9 can ensure efficient transmission of electric energy from the power supply to the electric field manufacturing device (the first flexible electrode layer 3 and the second flexible electrode layer 5). In the electric field manufacturing process, the smaller resistance of the copper wire can reduce the loss of electric energy during the transmission process, so that the electric energy output by the power supply can be used to generate the electric field to the maximum extent. And the copper wire has high mechanical strength and toughness. During the frequent grasping and releasing actions of the gripper, the lead wire needs to withstand certain mechanical stresses such as stretching, bending and torsion. The copper wire can resist the effects of these external forces and is not easy to break. It should be noted that the first lead wire 8 and the second lead wire 9 can also use other types of metal conductive wires, such as aluminum wires.

[0045] In some embodiments, the gripper also includes a flexible silicone shell 41, which is used to accommodate and seal the electrorheological elastomer. During the operation of the gripper, the flexible silicone shell 41 can prevent the electrorheological elastomer from accidentally short-circuiting with the surrounding conductive objects. At the same time, the silicone shell itself has little interference with the electric field, and the dielectric constant is relatively stable. It will not distort or shield the electric field like some conductive or magnetic materials. This allows the electric field to be evenly distributed inside the electrorheological elastomer, which is conducive to accurately controlling the stiffness of the electrorheological elastomer and ensuring the stable performance of the gripper.

[0046] In some embodiments, the gripper further includes a first flexible substrate layer 6 and a second flexible substrate layer 7. The two sides of the first flexible substrate layer 6 are connected to the flexible fabric gripper body 100 and the first flexible electrode layer 3 respectively. One side of the second flexible substrate layer 7 is connected to the silicone shell, and the other side is in contact with the air. The first flexible substrate layer 6 and the second flexible substrate layer 7 isolate and protect the first flexible electrode layer 3 and the second flexible electrode layer 5. The flexible substrate layer has a certain elasticity and buffering capacity. When the gripper is subjected to an unexpected external force impact, such as a collision with other objects during the grasping process, the flexible substrate layer can absorb and buffer part of the impact force, reducing damage to the internal electric field manufacturing device and the electrorheological elastomer.

[0047] In some embodiments, multiple sections of fabric can be bent or twisted. When each section of fabric is square, multiple sections of fabric can bend and deform; when each section of fabric is a non-square block, the non-square block here refers to a block with a non-square top surface, generally a parallelogram, but the blocks at the two ends are generally blocks with a right-angled trapezoidal top surface, and the two surfaces of each adjacent block for docking have the same shape. Multiple sections of fabric can be twisted and deformed, and the type of gripper is selected according to needs. The ability to bend and twist enables the gripper to perform more complex movements during operation and can adapt to a wider variety of objects.

[0048] Embodiment 2

[0049] This embodiment also provides a robot, including the gripper as described in the first embodiment, which can ensure that the gripping force is sufficient without damaging the object itself.

[0050] Embodiment 3

[0051] This embodiment provides a flexible fabric gripper body 100, a variable stiffness layer 4, a flexible electrode layer, and a method for preparing the gripper:

[0052] Preparation method of gripper

[0053] (1) Use hot melt glue to firmly connect the air pressure input port 1 (silicone air tube) to the air pressure drive layer of the flexible fabric gripper body 100;

[0054] (2) The first flexible substrate layer 6, the first flexible electrode layer 3, the electrorheological elastomer, the second flexible electrode layer 5 and the second flexible substrate layer 7 are arranged in sequence and connected by an adhesive, and the first flexible electrode layer 3 is bonded to the outer side of the air pressure driving layer of the flexible fabric gripper body 100 by the adhesive.

[0055] Method for preparing flexible fabric gripper body 100

[0056] The fabric air pressure driving layer 2 is made of fabric material and can be manufactured by a water-soluble mold laminating process:

[0057] (1) According to the designed size and shape requirements, a water-soluble polyvinyl alcohol (PVA) mold (twisting and bending) for preparing the fabric air pressure driving layer 2 is customized using 3D printing technology;

[0058] (2) Two pieces of fabric (made of thermoplastic polyurethane elastomer, TPU-N20D) were tightly wrapped around the PVA mold. During the wrapping and welding process, an electric soldering iron at a temperature of 220°C was used to precisely weld the overlapping edges of the two pieces of fabric, leaving a 2 cm unwelded area on the short side;

[0059] (3) placing the wrapped mold in a 60°C water bath. After about 4 hours, the PVA mold gradually dissolved, leaving the fabric air pressure driving layer 2.

[0060] (4) After the fabric air pressure driving layer 2 is fished out and air-dried, the air pressure input port 1 (silicone air tube) is firmly connected to the fabric air pressure driving layer 2 using hot melt adhesive in the reserved 2 cm unwelded area;

[0061] (5) Trim the excess welding edges with scissors.

[0062] Preparation method of first flexible electrode layer 3 and second flexible electrode layer 5

[0063] (1) The first flexible electrode layer 3 and the second flexible electrode layer 5 are both made by applying carbon grease on paper, and the paper can be ordinary A4 paper;

[0064] (2) The first lead wire 8 (copper wire) is adhered to the first flexible electrode layer 3, and the second lead wire 9 (copper wire) is adhered to the second flexible electrode layer 5;

[0065] (3) The first flexible electrode layer 3 is adhered to the first flexible base layer 6, and the second flexible electrode layer 5 is adhered to the second flexible base layer 7. (The first flexible base layer 6 and the second flexible base layer 7 are both made of silicone material and can be made by a casting process)

[0066] Preparation method of variable stiffness layer 4

[0067] (1) The electrorheological elastomer was prepared by dispersing titanyl barium oxalate particles (BaTiO(C2O4)2+CH2CONH2) synthesized by coprecipitation into polydimethylsiloxane (PDMS) and dimethyl silicone oil;

[0068] (2) The flexible silicone shell 41 is made of silicone material using a casting process;

[0069] (3) The electrorheological elastomer is placed in the flexible silicone shell 41.

[0070] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A gripper, characterized in that: include A flexible fabric gripper body, wherein the flexible fabric gripper body is formed by connecting a plurality of fabric sections, and the flexible fabric gripper body is connected to a driving device, and the driving device can drive the flexible fabric gripper body to grab and put down an object; A variable stiffness layer is covered on the non-gripping surface of the flexible fabric gripper body, and the stiffness of the variable stiffness layer can be changed.

2. The gripper according to claim 1, characterized in that: A closed cavity is arranged inside the flexible fabric gripper body, and the driving device is an air pump for filling the closed cavity with gas.

3. The gripper according to claim 1, characterized in that: The variable stiffness layer includes an electrorheological elastomer and an electric field manufacturing device. The electrorheological elastomer is arranged in the electric field manufacturing device. The electric field manufacturing device can generate an electric field, and the electric field can change the stiffness of the electrorheological elastomer.

4. The gripper according to claim 3, characterized in that: The electric field generating device comprises a first flexible electrode layer and a second flexible electrode layer, wherein the first flexible electrode layer and the second flexible electrode layer are respectively adhered to the two sides of the electrorheological elastomer, and the first flexible electrode layer is adhered to the non-grasping surface of the flexible fabric gripper body, and the first flexible electrode layer and the second flexible electrode layer can be connected to a power source to generate an electric field.

5. The gripper according to claim 4, characterized in that: It also includes a first lead wire and a second lead wire, the first lead wire is connected to the first flexible electrode layer, the second lead wire is connected to the second flexible electrode layer, and the first lead wire and the second lead wire are used to connect a power source.

6. The gripper according to claim 5, characterized in that: The first lead wire and the second lead wire are both copper wires.

7. The gripper according to claim 4, characterized in that: It also includes a flexible silicone shell, which is used to accommodate and seal the electrorheological elastomer.

8. The gripper according to claim 7, characterized in that: It also includes a first flexible substrate layer and a second flexible substrate layer, wherein the two sides of the first flexible substrate layer are respectively connected to the flexible fabric gripper body and the first flexible electrode layer, and one side of the second flexible substrate layer is connected to the silicone shell and the other side is in contact with the air.

9. The gripper according to claim 1, characterized in that: The multiple fabric sections can be bent or twisted. When each fabric section is a square, the multiple fabric sections can be bent and deformed; when each fabric section is a non-square block, the multiple fabric sections can be twisted and deformed.

10. A robot, characterized in that: Comprising a gripper as described in any one of claims 1-9.

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