1. The multi-degree-of-freedom soft mechanical arm driven by fluid is characterized in that a mechanical arm base body is arranged on the multi-degree-of-freedom soft mechanical arm driven by the fluid;

the driving elastic cavity is poured in the mechanical arm base body through silica gel;

the rigidity adjusting cavity is poured in the mechanical arm base body through silica gel and is arranged in a staggered mode with the driving elastic cavity;

the joint connecting piece is clamped and mounted with the mechanical arm base body;

and the joint sealing cover is fixedly arranged on the outer side of the joint connecting piece through a quick-plugging joint.

2. The multi-degree-of-freedom soft mechanical arm driven by fluid as claimed in claim 1, wherein the front end and the rear end of the driving elastic cavity are respectively sleeved with an elastic cavity front end plug and an elastic cavity rear end plug, and an elastic cavity inner layer is integrally arranged on the inner side of the driving elastic cavity.

3. The multi-degree-of-freedom soft mechanical arm driven by fluid as claimed in claim 1, wherein an elastic cavity constraint layer is arranged outside the driving elastic cavity.

4. The multi-degree-of-freedom soft mechanical arm driven by fluid as claimed in claim 1, wherein the middle part of the front end plug of the elastic cavity is provided with a through hole for the fluid to pass through.

5. The multi-degree-of-freedom soft mechanical arm using fluid driving of claim 1, wherein the driving elastic chamber and the stiffness adjusting chamber are at least 3 each.

6. A soft robot arm system equipped with the fluid-actuated multi-degree-of-freedom soft robot arm according to any one of claims 1 to 5, wherein the soft robot arm system is composed of a plurality of stages of the fluid-actuated multi-degree-of-freedom soft robot arms connected in series.

Background

Currently, the current state of the art commonly used in the industry is such that:

most of the traditional rigid robots are made of rigid materials with limited elastic deformation capacity, the shape of the traditional rigid robots is suitable for specific external constraints and obstacles, and the traditional rigid robots have the characteristic of high accuracy, but the traditional rigid robots are difficult to show high deformable capacity and adaptability to different environments, along with the continuous expansion of demand fields, special fields such as medical care, complex terrain exploration and the like provide more severe requirements for the robots, and the special robots capable of being suitable for unstructured environments become research hot directions.

The soft mechanical arm is light in structure and flexible and remarkable in movement; the existing soft mechanical arm is generally made of flexible materials such as silica gel or rubber, an air cavity is arranged inside the soft mechanical arm, and the air pressure inside the air cavity is changed by inflating or exhausting air in the air cavity to drive the contraction of the air cavity, so that the functions of integral expansion and contraction of the soft mechanical arm are realized. However, most of the existing soft mechanical arms can only realize the action of single degree of freedom or two degrees of freedom, and the prior art provides a soft mechanical arm, but only can realize spiral twisting action and cannot realize stretching and bending action; the mechanical arm provided by the second prior art can only realize bending at a joint, and the main body part can only realize single-degree-of-freedom stretching.

In summary, the problems of the prior art are as follows:

most of the existing soft mechanical arms can only realize the action of single degree of freedom or two degrees of freedom, such as only realizing the twisting motion or only finishing the bending motion, and are difficult to finish the bending and extending actions in all directions simultaneously.

The difficulty in solving the technical problems is as follows:

(1) the structure design of the soft mechanical arm and the forming process of the flexible structure.

(2) How to realize the modularization integration of the fluid driving system and the soft mechanical arm, ensure the reliable sealing of the fluid and the transmission in the multi-segment mechanical arm, and restrict the radial deformation of the soft mechanical arm.

The significance of solving the technical problems is as follows:

the invention can complete the motion of 3 degrees of freedom, and ensure the reliable sealing of the driving fluid and the modularized integration of the fluid driving system and the soft mechanical arm.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a multi-degree-of-freedom soft mechanical arm driven by fluid.

The invention is realized in such a way that the multi-degree-of-freedom soft mechanical arm driven by the fluid is provided with a mechanical arm base body;

the driving elastic cavity is poured in the mechanical arm base body through silica gel;

the rigidity adjusting cavity is poured in the mechanical arm base body through silica gel and is arranged in a staggered mode with the driving elastic cavity;

the joint connecting piece is clamped and mounted with the mechanical arm base body;

and the joint sealing cover is fixedly arranged on the outer side of the joint connecting piece through a quick-plugging joint.

Furthermore, the front end and the rear end of the driving elastic cavity are respectively sleeved with an elastic cavity front end plug and an elastic cavity rear end plug, and an elastic cavity inner layer is integrally arranged on the inner side of the driving elastic cavity.

Further, an elastic cavity constraint layer is arranged on the outer side of the driving elastic cavity.

Furthermore, a through hole for fluid to pass through is formed in the middle of the plug at the front end of the elastic cavity.

Further, the drive elastic cavity and the rigidity adjusting cavity are at least 3 respectively.

Another object of the present invention is to provide a soft arm system having the fluid-driven multi-degree-of-freedom soft robot arm mounted thereon, the soft arm system being formed by connecting a plurality of the fluid-driven multi-degree-of-freedom soft robot arms in series.

In summary, the advantages and positive effects of the invention are:

the invention provides a soft mechanical arm capable of realizing omnidirectional bending, stretching and variable rigidity, wherein the soft robot simulates a mollusk in nature, avoids using a rigid material, mostly adopts a formable material such as silica gel and the like, and has high flexibility and strong complex environment adaptability with large deformation by virtue of the natural flexibility and adaptability of the flexible material.

The soft mechanical arm is made of flexible materials, and due to the characteristic that the flexible materials are easy to deform, the soft mechanical arm is easy to deform passively under the influence of environmental conditions, so that the motion repeatability positioning precision is influenced, and meanwhile, the problem of low output force is caused by the flexible passive deformation of the soft mechanical arm, so the characteristic that the soft mechanical arm has variable rigidity is particularly important.

Drawings

FIG. 1 is a schematic diagram of the working principle of the soft mechanical arm of the invention provided by the embodiment of the invention;

in fig. 1: a. the omnidirectional bending schematic diagram of the soft mechanical arm; b. the stiffness adjustment of the soft mechanical arm is schematically shown.

FIG. 2 is a perspective view of a robotic arm according to an embodiment of the present invention.

FIG. 3 is a schematic front view of a soft robotic arm according to an embodiment of the present invention.

Fig. 4 is an exploded view of an embodiment of the present invention.

Fig. 5 is a cross-sectional view taken at i-i of fig. 3 in accordance with an embodiment of the present invention.

Fig. 6 is a right side view of fig. 3 provided by an embodiment of the present invention.

Fig. 7 is a left side view of fig. 3 provided by an embodiment of the present invention.

Fig. 8 is a cross-sectional view taken at ii-ii of fig. 3 in accordance with an embodiment of the present invention.

Fig. 9 is a cross-sectional view taken at iii-iii of fig. 3 in accordance with an embodiment of the present invention.

Fig. 10 is a schematic structural diagram of an inner elastic air cavity according to an embodiment of the present invention.

Fig. 11 is a schematic structural diagram of a constraint layer provided in an embodiment of the present invention.

Figure 12 is an experimental view of the soft body robot arm during single chamber pressurization.

FIG. 13 is a graph of driving pressure versus bend angle.

FIG. 14 is a graph of drive pressure versus actuator extension.

In the figure: 1. a mechanical arm base body; 2. the back end of the elastic cavity is blocked; 3. an elastic cavity inner layer; 4. the front end of the elastic cavity is provided with a plug; 5. a joint connector; 6. a joint sealing cover; 7. a quick connector; 8. a top end cap; 9. an air tube; 10. a stiffness adjustment chamber; 11. the elastic chamber is actuated.

Detailed Description

In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings.

The invention aims to invent and design a multi-freedom variable-rigidity soft mechanical arm, which can realize the actions of bending, twisting, stretching and the like and has high flexibility and large deformation capacity.

Fig. 1-11 show the basic principle and structural composition of the multi-degree-of-freedom soft mechanical arm, and the embodiment is illustrated by combining the above figures, and comprises a soft mechanical arm elastic base 1, an elastic cavity rear end plug 2, an elastic cavity inner layer 3, an elastic cavity restraint layer, a driving elastic cavity 11, a rigidity adjusting cavity 10, an elastic cavity front end plug 4, a joint connecting piece 5, a quick connector 7, a joint sealing cover 6, a top end cover 8 and an air pipe 9.

The elastic cavity is molded by silica gel casting, an elastic cavity restraint layer is additionally arranged outside the elastic cavity, the elastic cavity restraint layer can be formed by double-helix winding of fiber wires or structures such as a nylon ring and the like,

an elastic cavity inner layer 3 is fixed between the elastic cavity rear end plug 2 and the elastic cavity front end plug 4; the rear end part of the elastic cavity is blocked by an elastic cavity rear end plug 2 made of high-hardness elastic silica gel, an elastic cavity front end plug 4 is inserted into the front end of the elastic cavity, the elastic cavity front end plug 4 is also made of high-hardness elastic silica gel, and a circular through hole is formed in the middle of the elastic cavity front end plug 4 and is used for fluid to pass through. The rigidity adjusting cavity 10 is also molded by silica gel casting, and fine blocking particles are filled in the rigidity adjusting cavity, wherein the fine blocking particles can be round plastic balls, coffee beans and the like.

The driving elastic cavities 11 and the rigidity adjusting cavities 10 are arranged in a staggered mode, a plurality of silica gel cavities are uniformly arranged along the radial direction of the elastic base body 1 of the mechanical arm, and the number of the driving elastic cavities and the number of the rigidity adjusting cavities are at least 3 respectively. The front end part of the elastic cavity is inserted into a joint connecting piece 5, adhesive glue is coated outside the joint connecting piece 5, a circular through hole is formed in the middle of the joint connecting piece, a quick-plug connector 7 is inserted into the joint connecting piece 5, and the joint connecting piece 5 is connected with the quick-plug connector 7 through a joint sealing cover 6.

The quick connector is wrapped by a front end cover 8, and the front end cover 8 is made of high-hardness silica gel. An air pipe 9 is inserted on the top end cover 8.

The soft mechanical arm can independently use one section as a mechanical arm main body to finish corresponding actions, and can also be connected in series in multiple sections to form a super-redundancy soft mechanical arm.

Soft robot action embodiments:

taking the figure 1 (a) as an example, when the elastic cavity I is driven to inflate, the elastic cavity extends to drive the whole mechanical arm to bend, and when the gas in the cavity is unloaded or the gas in the cavity is pumped out, the mechanical arm straightens;

elongation and shrinkage: when the driving elastic cavity I, the driving elastic cavity II and the driving elastic cavity III are simultaneously inflated, the mechanical arm is extended, and when pressure is unloaded or three-cavity gas is pumped out, the mechanical arm is contracted;

adjusting the rigidity: as shown in fig. 1 (b), when the gas in the stiffness adjusting cavity is pumped out, the stiffness adjusting cavity is compressed under the action of the external atmospheric pressure, the internal circles can be extruded together, the overall structure hardness becomes hard, so that the stiffness of the mechanical arm is improved, and when the gas is filled into the cavity, the elastic cavity returns to the original state, the overall structure hardness becomes soft, so that the stiffness of the mechanical arm is reduced.

The invention respectively pressurizes a single cavity and two air cavities simultaneously, the driving pressure is from 0bar to 2bar, every 0.2bar is taken as a test point, fig. 12 is a relation graph of the driving pressure and the bending angle, fig. 13 is a software mechanical arm experimental graph during the pressurizing of the single cavity, fig. 14 is a relation graph of the driving pressure and the elongation of a driver, and when the driving pressure is 2.2bar, the bending angle of the software mechanical arm can reach 81 degrees, and the elongation can reach 23.6 percent.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.