Adhesion gripper for robust grabbing and dynamic capturing of three-dimensional object

Abstract

The invention discloses an adhesion gripper for robust grabbing and dynamic capturing of a three-dimensional object, which comprises a buckle pipe and a buckle disc, and the buckle pipe is clamped with the buckle disc and can move along the buckle disc; one end of the buckle pipe is rotatably connected with the ball socket structure, the ball socket structure comprises a hinge block and a connecting block which are connected with each other, the hinge block is rotatably connected with the buckle pipe, and the connecting block is connected with an elastic adhesive film which provides gripping force during gripping. And the hinging block is spherical and is matched with the buckling pipe in a clamping manner. And the connecting block is T-shaped. The gripper obtained by the invention has the characteristics of shape adaptability, energy absorption, reusability and adjustable rigidity; the gripper has excellent adaptability to various three-dimensional and dynamic objects, and the adhesive force of the gripper on a curved surface is higher than that of an existing adhesive gripper; due to the shape adaptability and the energy absorption characteristic, moving objects can be captured, objects higher in speed can also be captured compared with an existing gripper, and a thought is provided for processing complex curved surfaces and moving objects.

Description

Technical Field

[0001] The present invention belongs to a gripper, and specifically relates to an adhesive gripper for robust grasping and dynamic capture of three-dimensional objects. Background Art

[0002] Multifunctional grasping technology can flexibly adapt to and firmly grasp objects of various shapes, sizes, and materials, and can also control release. It has been widely used in daily life and advanced technology fields. These fields include robotic operation, fruit and vegetable harvesting, electronic component assembly, medical surgery, and prosthetics.

[0003] Currently, mechanical grippers are the most widely used design in various operating scenarios. They have high control precision, but high power consumption, rely on complex control and sensing systems, increasing weight and volume. In addition, these mechanical-based manipulators can only manipulate objects smaller than their own size and often apply excessive pressure, causing damage to fragile items.

[0004] Recently, adhesion force-based strategies have become promising solutions to address these challenges. The switchable adhesive manipulator has a simple structural design and has the following advantages: they can firmly adhere to objects without consuming additional energy, can grasp objects of various sizes and materials (even smooth planar objects much larger than themselves), and can achieve reliable grasping with only minimal pressure. This gentle pressure can minimize the risk of damage, so it is particularly suitable for handling fragile items.

[0005] However, when dealing with complex three-dimensional (3D) objects and high-speed moving targets, traditional adhesives face considerable challenges. When contacting a three-dimensional object, due to the different heights of the contact interface, the stored deformation energy and contact area will decrease, thus offsetting the adhesion force. In addition, the misalignment between the adhesive and the local object curvature will further weaken the conformal contact, thus greatly reducing the adhesion ability of the adhesive gripper on the three-dimensional surface. For moving objects, the elastic collision caused by the inherent elasticity of the adhesive often leads to rebound and detachment, and it is impossible to achieve robust grasping of three-dimensional dynamic objects. Summary of the Invention

[0006] Object of the Invention: In order to overcome the deficiencies in the prior art, the object of the present invention is to provide an adhesive gripper for robust grasping and dynamic capture of three-dimensional objects with good shape adaptability, energy absorption, reusability, and adjustable stiffness characteristics. The decoupled multi-stable structure formed by the connection of the snap tube and the snap disc provides good shape adaptability.

[0007] Technical solution: An adhesion gripper for robust grasping and dynamic capture of three-dimensional objects according to the present invention includes a snap tube and a snap disc. The snap tube is snap-connected to the snap disc and can move along the snap disc. One end of the snap tube is rotatably connected to a ball-and-socket structure. The ball-and-socket structure includes a hinge block and a connecting block connected to each other. The hinge block is rotatably linked to the snap tube, and the connecting block is connected to an elastic adhesion film that provides a grasping force during grasping.

[0008] Further, the hinge block is spherical and is in snap-fit with the snap disc. The ball-and-socket structure can rotate freely, increasing the adaptability to three-dimensional objects.

[0009] Further, the connecting block is T-shaped.

[0010] Further, a number of clamping blocks are arranged in an array on the outer surface of the snap tube. The clamping blocks include rectangular blocks and triangular blocks. The triangular blocks are arranged on the surfaces of the rectangular blocks. The angles of the triangular blocks close to two corners of the rectangular block are 0 to 90°.

[0011] Further, a number of circular holes are arranged in parallel on the inner surface of the snap disc. A number of circular rings are arranged in the circular holes. Slots are formed between adjacent circular rings.

[0012] Further, one end of the snap tube away from the ball-and-socket structure is connected to a driving device.

[0013] Further, the driving device includes an airbag and a driving plate. The airbag controls the movement of the driving plate by inflating and deflating. A number of driving rods corresponding to the circular holes of the snap disc are arranged on the driving plate. Further, the elastic adhesion film is a commercial elastic tape, preferably 3M VHB tape, and is connected to the connecting block through glue, providing an adhesion force, that is, the grasping force during grasping.

[0014] Further, the snap tube, the snap disc, and the ball-and-socket structure are all prepared by CAD modeling and 3D printing.

[0015] Working principle: Insert the snap tube into the arrayed snap tubes. The snap mechanical metamaterial formed by the snap tube and the snap disc has multistability, and can achieve shape adaptation and multi-level energy absorption. When grasping an object, the shape adaptability of the metamaterial and the ball-and-socket structure is used to increase the contact area of the gripper with the grasped object, and then increase the adhesion force (i.e., the grasping force) to grasp the object. When release is required, the airbag is inflated to make the driving plate move downward. The driving rod will push the snap tube to move so that the gripper no longer adapts to grasping the object, that is, the contact area is reduced, and then the grasping force is reduced to release the object.

[0016] Usage method: Connect the gripper to a screw motor or a robotic arm. Move the gripper above the object. The motor or the robotic arm drives the gripper to make it contact the object. When the adhesion force is sufficient to pick up the object, drive the gripper to the specified position again. Inflate the airbag to release the object.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following remarkable features:

[0018] 1. The obtained gripper has characteristics of shape adaptability, energy absorption, reusability, and adjustable stiffness;

[0019] 2. The gripper has excellent adaptability to various three-dimensional and dynamic objects, and has stronger adhesion force on curved surfaces than existing adhesive grippers;

[0020] 3. Due to the shape adaptability and energy absorption characteristics, the gripper can capture moving objects, and can also capture objects with faster speeds than previous grippers;

[0021] 4. The gripper not only expands the application scope of intelligent adhesion technology, but also provides innovative solutions for handling complex curved surfaces and moving objects;

[0022] 5. It is expected that the gripper will be widely applied in fields such as multifunctional assembly, outer space debris recovery, and heavy object operation. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of the present invention;

[0024] Figure 2 is a schematic connection diagram of the snap tube 1 and the snap disc 2 of the present invention;

[0025] Figure 3 is a partial enlarged view of part A of the present invention;

[0026] Figure 4 is a partial enlarged view of part B of the present invention;

[0027] Figure 5 is a top view of the snap disc 2 of the present invention;

[0028] Figure 6 is a front view of the ball socket structure 3 of the present invention;

[0029] Figure 7 is a schematic diagram when the driving device 5 deflates in the present invention;

[0030] Figure 8 is a schematic diagram when the driving device 5 inflates in the present invention;

[0031] Figure 9 is a schematic structural diagram of the driving rod 53 of the present invention;

[0032] Figure 10 is a schematic diagram of the process of grasping and releasing a glass ball in the present invention, where i is when contacting, ii is when lifting, iii is when releasing, and iv is when putting down;

[0033] Figure 11 It is a demonstration diagram of the multi-functional grasping of the gripper of the present invention;

[0034] Figure 12 It is a demonstration diagram of the connection between the gripper of the present invention and the robotic arm for grasping;

[0035] Figure 13 It is a comparison diagram of the adhesion strength performance between the gripper of the present invention and the control sample;

[0036] Figure 14 It is a comparison diagram of the design of the release drive plate and the debonding performance of the present invention;

[0037] Figure 15 Schematic diagram of the small ball grasped by the comparison sample and the gripper of the present application during the grasping movement. Detailed implementation manners

[0038] In the following embodiments, the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels. The experimental methods without specific conditions noted in the embodiments are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0039] Such as Figure 1 , the snap tube 1 of the adhesion gripper for robust grasping and dynamic capture of three-dimensional objects is snap-connected to the snap disk 2 and can move up and down along the snap disk 2. The ball-and-socket structure 3 needs to be assembled to the bottom of the snap tube 1 and can rotate freely, increasing the adaptability to three-dimensional objects. The elastic adhesion film 4 is attached to the lower surface of the connecting block 32. The elastic adhesion film 4 is a commercial elastic tape, 3M VHB double-sided tape, which is a film with elasticity and adhesion performance, providing the adhesion force, that is, the grasping force during grasping. The snap tube 1, the snap disk 2, and the ball-and-socket structure 3 are all prepared by 3D printing.

[0040] Such as Figures 2 - 5 , a number of blocks 11 are arrayed on the outer surface of the snap tube 1. The block 11 includes a rectangular block 111 and a triangular block 112, and the triangular block 112 is arranged on the surface of the rectangular block 111. A number of through circular holes 21 are arranged in parallel on the inner surface of the snap disk 2, and parallel circular rings 22 are arranged on the inner surface of the circular hole 21, and a card slot 23 is formed between two circular rings 22. The snap tube 1 and the snap disk 2 form a snap mechanical metamaterial with multi-stability. When the snap tube 1 is inserted into the card slot 23 of the snap disk 2, shape adaptation and multi-stage energy absorption can be achieved.

[0041] Using Solidworks 3D modeling software, draw the three-dimensional cylindrical snap tube 1, hexagonal snap disk 2, and ball-and-socket structure 3. The specific geometric parameters are: h 1 = 1.38 mm, h 2 = 0.95 mm, h 3 = 0.50 mm, h 4= 6.40 mm, α = 55°, β = 20°, Y = 0.6 mm, T b = 1.25 mm, L b = 4.15 mm, L t = 5.40 mm, L r = 2.07 mm, γ = 30°, the center spacing h of the unit 4 = 7.00 mm.

[0042] Such as Figure 6 , the ball socket structure 3 includes a hinged block 31 and a connecting block 32 that are connected to each other. The spherical hinged block 31 is rotatably linked to the snap tube 1, and the T-shaped connecting block 32 is connected to the elastic adhesion film 4 that provides a gripping force during grasping. The geometric parameters of the ball socket structure 3 are: h 6 = 1.5 mm, h 7 = 0.75 mm, D = 5.5 mm, d = 1 mm, l = 3.15 mm, r 1 = 1.75 mm, r 2 = 2.05 mm, R = 2.5 mm.

[0043] The preparation method of the above-mentioned adhesion gripper for robust grasping and dynamic capture of three-dimensional objects includes the following steps:

[0044] Step 1, using Solidworks 3D modeling software, draw the 3D snap tube 1, snap disc 2, and ball socket structure 3, and the specific parameters are as described above.

[0045] Step 2, import the model files of the snap tube 1, snap disc 2, and ball socket structure 3 into the 3D printing pre-processing software to add supports and slice processing, and then import them into the 3D printing device to produce the photosensitive resin snap tube 1, snap disc 2, and ball socket structure 3 samples.

[0046] Step 3, insert the ball socket structure 3 into the top groove of the snap tube 1, and then insert the snap tube 1 into the card slot 23 of the snap disc 2 to obtain a multi-stable mechanical metamaterial including a ball socket tip. Then, use UV glue to attach the 1 mm thick elastic adhesion film 4 to the connecting block 32 of the ball socket structure 3 and cure it by ultraviolet irradiation for 3 minutes to complete the preparation of the adhesion gripper for robust grasping and dynamic capture of three-dimensional objects.

[0047] Such as Figures 7 - 8 , one end of the snap tube 1 away from the ball socket structure 3 is connected to the driving device 5. The driving device 5 includes an airbag 51 and a driving plate 52. The airbag 51 controls the movement of the driving plate 52 by inflating and deflating, and a number of driving rods 53 corresponding to the circular holes 21 of the snap disc are arranged on the driving plate 52. The driving device 5 is designed to enable the gripper to release the grasped object, and the release driving rods 53 are designed in a spiral increasing form from the outside to the inside, such as Figure 9As shown, the height h of the driving rod 53 is arranged to increase successively from the outside to the inside, satisfying h n = h 1 +(n - 1)x, where h 1 is 0.5 mm, h 2 is 1 mm, …, h 19 is 9.5 mm, n is the quantity 19, and x is the increasing height of 0.5 mm. By inflating and deflating the gas, the movement of the airbag 51 pushing and releasing the driving plate 52 is controlled. The driving rod forces the snap tube 1 to move, making the snap tube 1 in the adhesion gripper no longer adapt to the shape of the grasped object, resulting in a decrease in the adhesion force and thus releasing the grasped object.

[0048] As Figure 10 , the adhesion gripper for robust grasping and dynamic capture of three-dimensional objects in this embodiment can be used in the process of grasping a glass ball, including: contacting, lifting, releasing, and putting down.

[0049] As Figure 11 , the adhesion gripper in this embodiment can perform multifunctional grasping, demonstrating the grasping performance of the gripper from two dimensions: the size of the grasped object and the complexity of the shape.

[0050] As Figure 12 , the gripper in this embodiment is integrated onto the robotic arm, and the snap disc 2 is connected to the robotic arm, and a dynamic grasping demonstration is carried out, successfully grasping a flying small ball.

[0051] Comparative Example 1

[0052] As Figure 13 shown, 2 control samples were prepared for comparing the adhesion performance of grasping. The rest of the structure of Comparative Sample 1 is the same as that of this embodiment, and the only difference is that: the snap tube 1 is cylindrical, and the outer surface omits the snap block 11. The rest of the structure of Comparative Sample 2 is the same as that of this embodiment, and the only difference is that: the snap disc 2 is omitted. The metamaterial gripper of this embodiment has strong adhesion performance for glass balls with different radii (20, 30, 40, 50 mm). Compared with Comparative Sample 1, the adhesion strength in Comparative Sample 2 has increased by 2 to 4 times. Further, due to the precise alignment adaptability provided by the snap disc 2, compared with Comparative Sample 2, the adhesion strength of the gripper doubles again.

[0053] Comparative Example 2

[0054] As Figure 14As shown, the release drive plate 52 is provided with raised drive rods 53, and the structural layout of these drive rods 53 has a significant impact on the adhesion switching ratio (i.e., the ratio of the adhesion strength before driving to the adhesion strength after driving). Four different configurations of the release drive plate - Design 1, Design 2, Design 3, and Design 4 - were compared, and each design has a unique configuration of the drive rods 53. Design 1, Design 2, and Design 3 were used as control groups. Design 1 adopts a flat plate structure without drive rods 53. Design 2 includes a configuration of drive rods 53 with the highest height h 1 in the center and 6 sub - highest heights h 2 randomly distributed around the perimeter, satisfying h 1 = 11 mm and h 2 = 4 mm. Both Design 3 and Design 4 are composed of drive rods 53 arranged in a hexagonal pattern, but the pillar height distribution patterns are opposite: in Design 3, the height gradually decreases from the outer edge to the center along a spiral path, satisfying h n = h 1 -(n - 1)x, where h 1 is 9.5 mm, h 2 is 9.0 mm,..., h 19 is 0.5 mm, n is the number 19, and x is the decreasing height of 0.5 mm. While in Design 4, the height gradually increases, which is the design form of the drive rods 53 in Example 1. The performance of these four designs was evaluated by measuring the adhesion force of a glass ball with a radius of 50 mm. Figure 14 Shows the minimum adhesion strength and adhesion switching ratio of each design after driving. The results show that the drive rods 53 of Design 4 (Example 1) exhibit the lowest adhesion strength (5 kPa) and the highest adhesion switching ratio (23.54) during the release process, significantly superior to other designs, indicating that it can effectively promote the debonding process and become the preferred solution for subsequent tests and applications.

[0055] Comparative Example 3

[0056] Figure 15 Is a comparison diagram of the gripper and the control sample for grasping dynamic objects. The rest of the structure of the control sample is the same as that of this embodiment, except that it does not include the clamping block 11, the ring 22, and the card slot 23. The test found that the gripper can catch the flying ball, while for the control sample when encountering a flying ball, the ball was not caught (i.e., it bounced back).

Claims

1. An adhesion gripper for robust grasping and dynamic capture of three-dimensional objects, characterized in that: The invention comprises a snap tube (1) and a snap disk (2), wherein the snap tube (1) is snapped with the snap disk (2) and can move along the snap disk (2); one end of the snap tube (1) is rotatably connected to a ball-and-socket structure (3), wherein the ball-and-socket structure (3) comprises an articulated block (31) and a connecting block (32) which are connected to each other, wherein the articulated block (31) is rotatably connected to the snap tube (1), and the connecting block (32) is connected to an elastic adhesive film (4) which provides a gripping force when grasping.

2. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 1, characterized in that: The hinge block (31) is spherical.

3. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 1, characterized in that: The connecting block (32) is T-shaped.

4. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 1, characterized in that: A plurality of clamping blocks (11) are distributed in an array on the outer surface of the clamping tube (1).

5. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 4, characterized in that: The card block (11) comprises a rectangular block (111) and a triangular block (112), and the triangular block (112) is arranged on the surface of the rectangular block (111).

6. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 5, characterized in that: The angles of the two corners of the triangular block (112) close to the rectangular block (111) are 0 to 90 degrees.

7. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 1, characterized in that: A plurality of circular holes (21) are arranged in parallel on the inner surface of the buckle plate (2), a plurality of circular rings (22) are arranged in the circular holes (21), and a clamping groove (23) is formed between the circular rings (22) and the adjacent circular rings (22).

8. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 1, characterized in that: One end of the buckle tube (1) away from the ball and socket structure (3) is connected to a driving device (5).

9. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 8, characterized in that: The driving device (5) comprises an air bag (51) and a driving plate (52); the air bag (51) controls the movement of the driving plate (52) by inflating and deflating air; and a plurality of driving rods (53) corresponding to the circular holes (21) of the buckle plate are arranged on the driving plate (52).

10. The adhesive gripper for robust grasping and dynamic capture of three-dimensional objects according to claim 1, characterized in that: The elastic adhesive film (4) is a commercial elastic tape, which is connected to the connecting block (32) by glue.

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