CN111267138A

CN111267138A - Variable rigidity soft body tongs based on elasticity bobble

Info

Publication number: CN111267138A
Application number: CN202010249547.0A
Authority: CN
Inventors: 焦志伟; 程月; 丁玉梅; 杨卫民
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2020-04-01
Filing date: 2020-04-01
Publication date: 2020-06-12

Abstract

The invention discloses a variable-rigidity soft gripper based on elastic small balls. Each execution unit is similar to one finger of a human body, the plurality of execution units realize the grabbing function, the execution units are long-strip-shaped fingers and at least comprise an air channel, and the air channel is at least provided with an air port. One or more small cavities are arranged on a substrate of the execution unit, each small cavity comprises an air port, a plurality of microspheres are filled in the small cavity, and the size of each microsphere is larger than that of the smallest hole of the air port. The small cavity can be at any position on the actuator unit where variable stiffness is required. The execution units are arranged on the base part through fixing parts according to the shape and the size of the object to be grabbed, and the fixing mode can be screw and nut connection. The air passage of the execution unit is driven by air pressure, the small cavity controls rigidity through the negative pressure device, and the soft gripper is enabled to have the characteristic of being rigid and flexible through the starting and closing of the negative pressure device.

Description

Variable rigidity soft body tongs based on elasticity bobble

Technical Field

The invention relates to a flexible gripper with variable rigidity, and belongs to the field of robot research.

Background

Mechanical devices such as traditional rigid grippers manufactured according to functions and shapes of human hands are widely applied to industrial production and life of people, automation of industrial production is achieved, and meanwhile life level of people is improved.

At present, the soft robot has wide application prospect in the fields of bionics, industrial grasping and holding and medical rehabilitation. By organically combining a pneumatic soft driver and a particle soft capsule universal gripper, the Korean Fenglin et al at the university of the south of the middle school in 2019 and 5 months designs a bending soft driver capable of realizing active controllable deformation and rigidity regulation, wherein the driver can actively control the shape of the driver, conveniently realize rigidity regulation, and improve the bearing capacity by about 2.75 times.

The soft robot is a brand new direction for robot research, and the soft gripper overcomes the defects of poor interaction between the traditional rigid gripper and the environment, poor adaptability to complex environments, inflexibility and the like, so the soft gripper has a very wide application prospect. However, since the research on the soft grip has just started, the technology of the soft grip in terms of structure, driving, sensing and controlling is not mature, and further research and exploration are needed, so that the research on the soft grip has certain difficulties.

Disclosure of Invention

The invention aims to provide a soft gripper with variable rigidity to overcome the defect that the soft gripper only can provide flexible gripping and cannot realize variable rigidity.

In order to achieve the purpose, the invention adopts the following technical scheme: a variable-rigidity soft gripper based on elastic small balls comprises a plurality of execution units, a fixing part and a base part. Each execution unit is similar to one finger of a human body, the plurality of execution units realize the grabbing function, the execution units are long-strip-shaped fingers and at least comprise an air channel, and the air channel is at least provided with an air port. One or more small cavities are arranged on a substrate of the execution unit, each small cavity comprises an air port, a plurality of microspheres are filled in the small cavity, and the size of each microsphere is larger than that of the smallest hole of the air port. The small cavity can be at any position on the actuator unit where variable stiffness is required. The execution units are arranged on the base part through fixing parts according to the shape and the size of the object to be grabbed, and the fixing mode can be screw and nut connection.

The execution unit is fixed with the fixed part and the base part to form the flexible gripper with variable rigidity based on the elastic small balls. The air passage of the execution unit and the air pipe of the small cavity can pass through the air holes of the fixed part and the base part to be connected with a required air pump.

The variable-rigidity soft gripper based on the elastic small balls changes the bending degree of the execution unit by controlling the air pressure of the inflation air pump, and the larger the air pressure is, the larger the bending degree of the soft gripper is. The small cavity of the execution unit substrate is driven by a negative pressure device, and when the negative pressure device is not started, gaps among the elastic small balls in the small cavity are larger, so that the characteristic of a flexible material is shown; when the negative pressure device is started, the gap between the elastic small balls in the small cavity is reduced, so that the friction force between the elastic small balls is increased rapidly, the rigidity of the matrix at the position of the small cavity of the execution unit is increased, and the characteristic that the rigidity of the soft gripper can be changed at any position is realized.

According to the variable-rigidity soft gripper based on the elastic small balls, the elastic small balls can be absent in part of small cavities. The small cavity without the elastic small ball is inflated, and the small cavity with the elastic small ball is vacuumized, so that the elastic small ball is bent and grabbed.

According to the technical scheme, compared with the prior art, the invention has the following advantages: firstly, the variable rigidity characteristic of any part of the soft gripper can be realized; secondly, the rigidity changing method is easy to realize.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, but do not constitute a limitation of the invention. In the drawings:

fig. 1 is an external view of a variable stiffness soft grip based on elastic beads.

Fig. 2 is a top view of a variable stiffness soft grip based on elastic pellets.

Fig. 3 is a half sectional view of an actuator unit.

Fig. 4 is an external view of a fixing portion.

Fig. 5 is an external view of a base portion.

Fig. 6 is a schematic view of the execution unit when inflated.

Fig. 7 is a schematic view of the execution unit when it is inflated and vacuumized.

In the figure: 1-an execution unit, 2-a fixing part, 3-a base part, 4-a fixing bolt, 5-a fixing nut, 1-1-a small cavity, 1-2-an air passage, 1-3-an air pipe for vacuumizing, 1-4-an air pipe for inflating, 3-1-an air pipe hole for vacuumizing and 3-2-an air pipe hole for inflating.

Detailed Description

The following is further described with reference to the accompanying drawings.

First, fig. 1 is an appearance schematic diagram of a variable-stiffness soft gripper based on elastic small balls, which includes a fixing portion 2, a

base portion

3, 4 execution units 1, a plurality of fixing bolts 4 and a plurality of fixing nuts 5.

The actuator unit 1 in fig. 3 comprises an air duct 1-2 and a small cavity 1-1. The outer layer of the small cavity 1-1 is a silica gel layer with the diameter of 1mm-2mm, a plurality of elastic small balls with the diameter of about 2mm are wrapped inside the small cavity 1-1, and the tail end of the small cavity 1-1 is connected with a negative pressure device through an air pipe 1-3 for vacuumizing. The air passage 1-2 is connected to the air pressure device through an air tube 1-4 for inflation. The fixed part 2 and the base part 3 in fig. 1 are both manufactured using a 3D printing method.

The air pipe and the air hole in the execution unit 1 are bonded together through silica gel. As shown in fig. 1, the actuator unit 1, the fixing portion 2 and the base portion 3 are fixed together by a fixing bolt 4 and a fixing nut 5, and the fixing portion 2 and the base portion 3 are shown in fig. 4 and 5. The air tubes 1-3 for evacuation and the air tubes 1-4 for inflation in fig. 3 exit through the evacuated air tube aperture 3-1 and the inflation air tube aperture 3-2 of the base portion 3 of fig. 2, thereby connecting the air supply means. The base part 3 is attached to the rigid robot arm by means of fixing bolts 4 and fixing nuts 5.

The air passages 1-2 of the execution unit 1 are inflated through the air pipes 1-4 for inflation, the bending degree of the soft hand grip is changed by controlling the air pressure of the inflation air pump, and the larger the air pressure of the air pump is, the larger the bending degree of the execution unit 1 is. Fig. 6 is a schematic view of the inflation of the execution unit 1. The small cavity 1-1 at the bottom of the execution unit 1 is connected with a negative pressure device through an air pipe 1-3 for vacuumizing, and whether the small cavity 1-1 is subjected to rigidity changing is controlled by controlling the opening and closing of the negative pressure device. When the negative pressure device is started, the negative pressure device vacuumizes the small cavity 1-1, so that gaps among the elastic small balls in the small cavity 1-1 are reduced, and the small cavity 1-1 is arranged at the bottom of the execution unit 1, so that the rigidity of a base body at the bottom of the execution unit 1 is increased, and the gripping force can be increased and the characteristics of hardness and softness of the soft gripper can be realized. Fig. 7 is a schematic diagram of the inflation and evacuation of the execution unit 1, wherein the cavity of the elastic ball is evacuated and the cavity of the inelastic ball is inflated.

The above description is provided for the working principle and connection mode of the present invention, and is explained with reference to the drawings. However, the present invention is not limited to the above-mentioned connection method, and any local adjustment based on the above-mentioned connection method is within the scope of the spirit of the present invention.

Claims

1. The utility model provides a variable rigidity software tongs based on elasticity bobble which characterized in that: the device comprises a plurality of execution units, a fixed part and a base part, wherein each execution unit is similar to one finger of a person, the execution units realize a grabbing function, are long-strip-shaped fingers and at least comprise an air passage, and the air passage is at least provided with an air port; one or more small cavities are arranged on a substrate of the execution unit, each small cavity comprises an air port, a plurality of microspheres are filled in the small cavity, and the size of each microsphere is larger than that of the smallest hole of the air port; the small cavities are arranged at any positions on the execution units needing rigidity changing, and the execution units are arranged on the base part through fixing parts according to the shape and the size of a grabbed object, wherein the fixing mode can be that screws are connected with nuts; the air passage of the execution unit and the air pipe of the small cavity can pass through the air holes of the fixed part and the base part to be connected with a required air pump.

2. The flexible soft gripper based on elastic pellets as claimed in claim 1, wherein: and part of the small cavities are not provided with elastic balls.

3. The flexible soft gripper based on elastic pellets as claimed in claim 1, wherein: the outer layer of the small cavity is a 1mm-2mm silica gel layer, and a plurality of elastic small balls with the diameter of about 2mm are wrapped inside the small cavity.

4. The flexible soft gripper based on elastic pellets as claimed in claim 1, wherein: the small cavity at the bottom of the execution unit is connected with the negative pressure device through an air pipe for vacuumizing, and whether the small cavity changes rigidity or not is controlled by controlling the opening and closing of the negative pressure device.

5. The flexible soft gripper based on elastic pellets as claimed in claim 2, wherein: the cavity of the elastic small ball is vacuumized, and the cavity of the inelastic small ball is inflated.