CN109249385B

CN109249385B - Variable-rigidity pneumatic soft driver based on particle blockage

Info

Publication number: CN109249385B
Application number: CN201811170700.XA
Authority: CN
Inventors: 胡俊峰; 梁龙; 林茂虎; 程亮亮
Original assignee: Jiangxi University of Science and Technology
Current assignee: Jiangxi University of Science and Technology
Priority date: 2018-10-09
Filing date: 2018-10-09
Publication date: 2022-01-14
Anticipated expiration: 2038-10-09
Also published as: CN109249385A

Abstract

The invention discloses a variable-stiffness pneumatic soft driver based on particle blocking, which consists of a blocking layer and a driving layer, wherein the blocking layer and the driving layer are connected in an upper-lower layer relationship, the driving layer is positioned on the upper layer, and the driving layer realizes the bending deformation of the driver; the blocking layer is positioned at the lower layer and realizes the variable rigidity of the driver by using particle blocking. The flexible bag of the blocking layer is of a strip-shaped flexible film structure and consists of an upper part and a lower part, wherein the section of the upper part of the flexible film is semicircular, and the section of the lower part of the flexible film is rectangular, so that a cavity capable of being filled with blocking particles is formed. The rigidity change of the blocking layer is realized by the blocking particles respectively showing a flow state and a solid state in a non-vacuum state and a vacuum state. The expansion deformation layer of the driving layer is composed of a plurality of expansion airbags which are linearly arranged at equal intervals, the external structure of each expansion airbag is arched, and the internal structure of each expansion airbag is an arched groove. The stiffness change of the driver is adjusted by the stiffness change of the blocking layer in the non-vacuum state and the vacuum state.

Description

Variable-rigidity pneumatic soft driver based on particle blockage

Technical Field

The invention relates to a variable-stiffness pneumatic soft body driver based on particle blockage, belongs to the field of soft body robots, has wide application prospects in the fields of exploration rescue, object grabbing and the like, and is suitable for grabbing objects which are complex in appearance, soft in surface and easy to damage.

Background

The traditional driver mainly has a rigid structure and is widely applied to the fields of industrial production, special processing, medical rescue and the like. Although the traditional rigid driver has high controllability and grabbing stability, the traditional rigid driver has large volume, poor adaptability and low flexibility, cannot meet the task requirement of grabbing objects with different complex shapes, and the rigid shell of the traditional rigid driver is easy to damage the clamped objects, so that the safety cannot be ensured. Therefore, the software driver which has strong adaptive capacity, high flexibility, fast response and stable capture has extremely high research potential.

The existing software drivers include chemical reaction driving, shape memory alloy driving, dielectric elastomer driving and pneumatic driving. At present, the air pressure drive is applied to the fields of medical operation, object grabbing, bionic motion and the like because the air pressure drive takes nontoxic and easily-obtained air as a power source and is low in cost and easy to realize. For example, a starfish pneumatic soft driver developed by Harvard university has strong adaptability, but small grabbing force and poor object grabbing stability; a pneumatic soft driver with a cavity structure developed by Harvard university has large bending shape, but low rigidity and poor extraction effect; the pneumatic soft robot gripper which is developed by Chicago university and realizes self-adaptive gripping by utilizing particulate matter blocking has good wrapping property on gripped objects, strong self-adaptive capacity and small gripping force; a fiber reinforced pneumatic soft driver developed by Harvard university has large gripping force, realizes the change of the motion form of the soft driver through different winding ways, but has larger required air volume and slower response.

An ideal soft body driver, which can realize the deformation and bending under low rigidity and passively adapt to the shape of an object in function; the object is stably clamped and controlled to move under high rigidity. Variable stiffness is an effective solution to this problem. Common methods of varying stiffness are particle blocking, lamellar blocking, and dielectric elastomers, among others. However, the dielectric elastomer needs high voltage, and has poor safety and is difficult to realize; the layered obstruction realizes rigidity change by using friction force between thin layers, but the manufacturing is more complex and the material selection is difficult. Therefore, the currently common method of varying stiffness is particle blocking, which utilizes the distinct properties exhibited by the blocking material in the normal state and the vacuum state to realize the variation of stiffness, i.e. the particles exhibit a "fluid" state in the normal state, with lower stiffness; the vacuum state shows a solid state, and the rigidity is higher.

Disclosure of Invention

The invention aims to provide a variable-rigidity pneumatic soft driver based on particle blockage, and the designed soft driver has the advantages of variable rigidity, large output force, high response speed and the like.

The technical scheme adopted by the invention is as follows:

the variable-rigidity pneumatic soft driver comprises a blocking layer 1 and a driving layer 2, wherein the blocking layer and the driving layer are connected in an upper-lower layer relationship, the components of the variable-rigidity pneumatic soft driver are shown in figure 1, the driving layer is positioned on the upper layer, and the driving layer realizes the bending deformation of the driver; the blocking layer is positioned at the lower layer and realizes the variable rigidity of the driver by using particle blocking.

The structure of the blocking layer is shown in fig. 2, and the blocking layer structure is composed of a flexible bag 3, a gas pipe 4 with a filtering function and blocking particles 5. The flexible bag 3 is a strip-shaped flexible film structure and consists of an upper part and a lower part, wherein the section of the upper part of the flexible film is semicircular, and the section of the lower part of the flexible film is rectangular. A cavity is formed, with a semicircular upper part and a rectangular lower part, which can be filled with the blocking particles 5. The round protrusion structure design increases the volume of blocking particles in the blocking layer, increases the rigidity of the soft driver, reduces the air quantity required by the driving layer and improves the response speed of the driver. The blocking particles 5 are uniformly filled in the flexible bag 3, and in a non-vacuum state, the spacing between the blocking particles 5 is in a loose state, namely the blocking particles 5 can flow in the flexible bag 3, and the rigidity of a blocking layer is lower; when the flexible bag 3 is vacuumized, the distance between the blocking particles in the flexible bag 3 is reduced, the friction force between the blocking particles 5 is increased, the blocking particles 5 are in a compact state, the blocking particles 5 cannot flow in the flexible bag 3, and the rigidity of the blocking layer is increased. The change in stiffness of the blocking layer is thus achieved by means of the blocking particles 5 in a fluid state and a solid state in a non-vacuum and vacuum state, respectively. The air tube 4 with the filtering function is introduced into the flexible bag, so that the flexible bag can be used for extracting a vacuum state, and meanwhile, blocking particles are prevented from being sucked away during vacuum extraction.

The driving layer is composed of an expansion deformation layer 6 and a second air pipe 7, as shown in fig. 3. The expansion deformation layer is composed of a plurality of expansion airbags 8 which are linearly arranged at equal intervals, the external structure of each expansion airbag is arched, and the internal structure of each expansion airbag is an arched groove 9. When the expansion deformation layer is inflated, the inner wall of the groove is expanded, stretched and deformed under the action of air pressure by the arch-shaped groove, so that the expansion deformation layer is expanded, stretched and deformed, but the blocking layer connected with the expansion deformation layer is not stretched and deformed, so that the driving layer is bent and deformed. The second air pipe 7 is communicated with the expansion deformation layer and is used for inflating the expansion deformation layer.

The variable-stiffness pneumatic soft driver is shown in fig. 4, and the driver consists of a driving layer structure and a blocking layer structure, wherein the driving layer structure and the blocking layer structure are connected in an upper-lower layer relationship. Meanwhile, the blocking layer acts as a strain limiting layer of the driving layer, and the balloon effect of the driving layer is limited. The soft driver has two working states, wherein the first working state is a driving state, the driving layer structure is in an inflated state, the driving layer structure generates bending deformation to realize driving, the blocking layer structure is in a non-vacuum state, blocking particles of the blocking layer structure are in a loose state, and the rigidity of the driver is smaller; the second working state is a variable stiffness state, the driving layer structure is in an inflated state, and the driving layer keeps a bending deformation state; the blocking layer structure is in a vacuum state, the spacing between blocking particles is reduced, the blocking layer structure is in a compact state, the rigidity of the driver is increased, and the rigidity changing function is realized. Therefore, the pneumatic soft driver adjusts the rigidity change of the driver by changing the rigidity of the blocking layer structure.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) according to the soft driver designed by the invention, the driving layer adopts the design that the expansion air bags are linearly arranged at equal intervals, and compared with the traditional fiber reinforced driver, the gaps among the expansion air bags enable the driver to be more easily bent and deformed;

(2) the soft driver designed by the invention is provided with the blocking layer structure, compared with the traditional soft driver, the soft driver has the advantages of variable rigidity, large output force and the like, and meanwhile, the blocking layer can play a role of a strain limiting layer and limit the balloon effect of the driving layer;

(3) according to the soft body driver designed by the invention, the circular protrusion structure is arranged on the part of the flexible film on the flexible bag of the blocking layer, so that the volume of blocking particles in the blocking layer is increased, the rigidity of the soft body driver is increased, the air quantity required by the driving layer is reduced, and the response speed of the driver is improved.

Drawings

FIG. 1 is a conceptual diagram of a software driver;

FIG. 2 is a schematic diagram of a software driver blocking layer architecture;

FIG. 3 is a diagram of a software driver layer architecture;

FIG. 4 is a diagram of a software driver architecture;

in fig. 1, blocking layer of the software driver; 2. a driving layer of the soft driver;

in fig. 2, 3, a flexible bladder; 4. an air tube having a filtering function; 5. blocking particles;

in fig. 3, 6, an expansion deformation layer; 7. a second air pipe; 8. inflating the balloon; 9. an arcuate recess.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1-4, the variable stiffness pneumatic soft body driver based on particle blocking comprises a blocking layer 1, a driving layer 2; the blocking layer comprises a flexible bag 3, a trachea 4 with a filtering function and blocking particles 5; the driving layer includes an expansion deformation layer 6 and a second air pipe 7.

The partial flexible film on the flexible bag of the blocking layer is made of a material with higher hardness and has a protruded cavity structure, so that the volume of blocking particles in the blocking layer can be increased, the maximum rigidity of the soft driver is improved, the air quantity required by the driving layer is reduced, and the response speed of the driver is improved; the protruding structure can also limit the balloon effect of the driving layer well after the blocking layer is filled with blocking particles. When the driving layer is inflated to bend and deform, the blocking particles in the blocking layer are in a normal state, the friction force among the particles is small, the blocking particles show a fluid property, at the moment, the rigidity of the blocking layer is low, and the soft driver is easy to bend and deform and has good self-adaptive capacity and can passively adapt to the complex shape of a grabbed object; after the driving layer achieves the expected deformation, the blocking particles are in a vacuum state by the vacuum pump, the friction force among the particles is large, the blocking particles show solid properties, the rigidity of the blocking layer is high at the moment, and the soft driver can realize the stable grabbing of the grabbed objects.

The expansion deformation layer in the driving layer is inspired by the corrugated shape and is linearly arranged by a plurality of expansion air bags at equal intervals, and the gaps among the expansion air bags enable the driver to be more easily bent and deformed. When the driving layer is inflated, the internal air pressure is increased, the inner wall of the arched air bag expands, and the driving layer bends and deforms to drive the soft driver to bend.

The soft driver with variable rigidity, large output force and high response speed can be better realized through the above embodiment.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.

Claims

1. A pneumatic soft actuator of variable rigidity based on particle blocking, characterized by that, the soft actuator is made up of blocking layer and driving layer, driving layer and blocking layer are connected in upper and lower layers, the driving layer locates at the upper strata, the driving layer realizes the bending deformation of the actuator; the blocking layer is positioned at the lower layer and realizes the variable rigidity of the driver by using particle blocking; the flexible bag is of a strip-shaped flexible film structure and consists of an upper part and a lower part, the section of the upper part of the flexible film is semicircular, the section of the lower part of the flexible film is rectangular, a cavity with the upper part being semicircular and the lower part being rectangular is formed, the cavity can be used for filling the blocking particles, the volume of the blocking particles in the blocking layer is increased by the cavity, the rigidity of the soft driver is increased, the air quantity required by the driving layer is reduced, and the response speed of the driver is improved; the expansion deformation layer of the driving layer is composed of a plurality of expansion airbags which are linearly arranged at equal intervals, the external structure of each expansion airbag is arched, the internal structure of each expansion airbag is an arched groove, and the inner wall of each arched groove generates expansion, stretching and deformation under the action of air pressure, so that the expansion deformation layer generates expansion, stretching and deformation, and the driving layer generates bending deformation; the blocking layer acts as a strain limiting layer for the driving layer.

2. The variable stiffness pneumatic soft driver as claimed in claim 1, wherein the blocking particles are uniformly filled in the flexible bag, and in a non-vacuum state, the spacing between the blocking particles makes the blocking particles loose, and the blocking particles can flow in the flexible bag; when the flexible bag is in a vacuum state, the distance between the blocking particles in the flexible bag is reduced, so that the flexible bag is in a compact state, the blocking particles cannot flow in the flexible bag, and the rigidity change of the blocking layer is realized by respectively showing a flow state and a solid state in a non-vacuum state and a vacuum state by using the blocking particles.

3. The variable stiffness pneumatic soft actuator of claim 1, wherein the stiffness change of the actuator is adjusted by a stiffness change of the blocking layer in a non-vacuum state and a vacuum state.