CN111203912A

CN111203912A - Five-degree-of-freedom flexible arm driven by fluid and tendon rope in mixed mode

Info

Publication number: CN111203912A
Application number: CN202010047138.2A
Authority: CN
Inventors: 朱延河; 李相龙; 王天铄; 赵杰
Original assignee: Harbin Institute of Technology Shenzhen
Current assignee: Harbin Institute of Technology Shenzhen
Priority date: 2020-01-16
Filing date: 2020-01-16
Publication date: 2020-05-29
Anticipated expiration: 2040-01-16
Also published as: CN111203912B

Abstract

A five-degree-of-freedom flexible arm driven by a mixture of fluid and tendon, it includes a secondary mechanism; the first-level mechanism includes a small-end connecting flange, a large-end connecting flange, a closed hollow tower-type bellows-shaped flexible body and at least three Bowden wires tendon rope; the second-level mechanism includes a rigid platform and at least three steel wire rope tendon ropes; the small end and the large end of the closed hollow tower corrugated tubular flexible body are respectively fixed with a small end connecting flange and a large end connecting flange, and at least three abalone The boarding tendons are uniformly distributed on the outer side of the airtight hollow tower type corrugated tubular flexible body along the circumferential direction; at least three steel wire rope tendons are slid in the Bowden wiring tendons in one-to-one correspondence, and the middle part of the rigid platform and the small end are connected to the middle part of the flange connection, and the rigid platform swings relative to the small end connecting flange. The invention can realize the ability of actively changing the stiffness, greatly enhance the load-bearing ability of the flexible arm, and can quickly adjust the position and posture of the end platform.

Description

Five-degree-of-freedom flexible arm driven by fluid and tendon rope in mixed mode

Technical Field

The invention relates to a flexible arm, in particular to a five-degree-of-freedom flexible arm driven by fluid and a tendon rope in a mixed mode.

Background

In the field of robots, as the technology of mechanical arms is developed, the research on flexible mechanical arms has become a new focus in the field of robot research. The flexible mechanical arm is a robot system with multiple degrees of freedom, generally has an under-actuated infinite degree of freedom, is generally made of flexible materials, has the characteristics of high flexibility, complex environment adaptability, safe man-machine interaction and the like, relates to multidisciplinary cross fusion of materials science, bionics, mechanical design and manufacture, sensor technology and the like in research, provides reference and technical support for flexible material application, bionic robot research and the like in development, and has wide application prospects in the aspects of industrial production, medical operations, disaster relief detection, life nursing and the like. The existing flexible continuous body mechanical arm mainly adopts a wired driving mode, a pneumatic artificial muscle driving mode, a low-melting-point alloy driving mode and the like. Most of the driving modes have higher requirements on external environmental conditions, and the flexible arm body is low in rigidity and poor in bearing capacity and does not have the capacity of bearing heavy load operation.

Disclosure of Invention

The invention provides a five-degree-of-freedom flexible arm driven by mixing fluid and a tendon rope, aiming at overcoming the defects of the prior art. The flexible arm forms coupling confrontation with external tendon rope tension by means of fluid pressure, the ability of active rigidity changing can be realized, the load bearing ability of the flexible arm is greatly enhanced, and the position and the posture of the tail end platform can be quickly adjusted.

The technical scheme of the invention is as follows:

the five-freedom flexible arm driven by fluid and tendon rope mixture includes two-stage mechanism; the first-stage mechanism comprises a small end connecting flange, a large end connecting flange, a closed hollow tower type corrugated pipe-shaped flexible body and at least three bowden cable tendon ropes; the second-stage mechanism comprises a rigid platform and at least three steel wire rope tendons;

a small end connecting flange and a large end connecting flange are respectively fixed on the small end and the large end of the closed hollow tower type corrugated pipe shaped flexible body, a driving interface for controlling the internal fluid pressure is arranged on the large end surface of the closed hollow tower type corrugated pipe shaped flexible body, at least three bowden cable tendon ropes are uniformly distributed on the outer side of the closed hollow tower type corrugated pipe shaped flexible body along the circumferential direction and penetrate through a side ear channel on the outer side of the closed hollow tower type corrugated pipe shaped flexible body, one end of each bowden cable tendon rope is fixed on the small end connecting flange, and the other end of each bowden cable rope penetrates through the large end connecting flange and is driven by an external driving; the at least three steel wire rope tendon ropes are slidably arranged in the Bowden wire rope tendon ropes in a one-to-one correspondence mode, one end of each steel wire rope tendon rope stretches out of the small end connecting flange and is fixedly connected with the rigid platform, the other end of each steel wire rope tendon rope stretches out of the Bowden wire rope and is driven by the external driving device, the middle of the rigid platform is connected with the middle of the small end connecting flange, and the rigid platform swings relative to the small end connecting flange.

Furthermore, the closed hollow tower type corrugated pipe shaped flexible body is made of polyurethane thermoplastic elastomer.

Compared with the prior art, the invention has the beneficial effects that:

1. the flexible arm adopts a two-stage parallel five-degree-of-freedom tower structure design in structure, the first-stage mechanism is a tower-type corrugated pipe structure, telescopic motion can be realized, bending motion in all directions can be realized, the deformation amplitude is large, and the motion has three degrees of freedom; the second-stage mechanism is a rigid platform structure which swings around the axis and can swing with two degrees of freedom.

2. The driving carrier of the flexible arm adopts the mixed driving of fluid and the tendon rope, the fluid is injected into the tower-type corrugated tubular structure of the first-stage structure, the fluid pressure and the external tendon rope tension form coupled countermeasures, the capability of actively changing rigidity is realized, and the load bearing capability of the flexible arm is greatly enhanced.

3. The tower type corrugated pipe-shaped flexible body of the first-stage mechanism of the flexible arm is made of a high-strength polyurethane elastomer rubber (TPU) material in a 3D printing mode, the Shore hardness is 92A, the material enables the first-stage structure to achieve large-amplitude deformability, coupling of fluid and acting force of a tendon rope is fully exerted, and the active variable stiffness performance of the first-stage structure is greatly improved.

4. The second-stage mechanism of the flexible arm adopts a light ball bearing as a base, and when acting force is applied by the three tendon ropes, the second-stage mechanism can swing quickly to adjust the position and the posture of the rigid platform.

The invention will be further described with reference to the accompanying drawings and embodiments:

drawings

FIG. 1 is a perspective view of a five degree-of-freedom flexible arm of the present invention driven by a combination of fluid and tendon ropes;

FIG. 2 is a front view of a five degree-of-freedom flexible arm of the present invention driven by a combination of fluid and tendon ropes;

FIG. 3 is a cross-sectional view taken along line B-B of FIG. 2;

fig. 4 is a side view of fig. 2.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the embodiments described below are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-4, the fluid and tendon rope hybrid driven five-degree-of-freedom flexible arm of the present embodiment includes a secondary structure;

the first-stage structure comprises a small end connecting flange 1, a large end connecting flange 2, a closed hollow tower type corrugated pipe shaped flexible body 3 and at least three bowden cable tendon ropes 4; the second-level structure comprises a rigid platform 5 and at least three steel wire rope ropes 6;

a small end connecting flange 1 and a large end connecting flange 2 are respectively fixed on the small end and the large end of the closed hollow tower type corrugated pipe shaped flexible body 3, a driving interface 3-1 for controlling the internal fluid pressure is arranged on the large end surface of the closed hollow tower type corrugated pipe shaped flexible body 3, at least three bowden cable tendon ropes 6 are uniformly distributed on the outer side of the closed hollow tower type corrugated pipe shaped flexible body 3 along the circumferential direction and penetrate through a side ear channel 3-2 on the outer side of the closed hollow tower type corrugated pipe shaped flexible body 3, one end of each bowden cable rope is fixed on the small end connecting flange 1, and the other end of each bowden cable rope penetrates through the large end connecting flange 2 and is driven by an external driving device;

at least three steel wire rope tendon ropes 6 are arranged in the Bowden wire tendon rope 4 in a sliding mode in a one-to-one mode, one end of each steel wire rope tendon rope stretches out of the small-end connecting flange 1 and is fixedly connected with the rigid platform 5, the other end of each steel wire rope stretches out of the Bowden wire tendon rope 4 and is driven by an external driving device, the middle of the rigid platform 5 is connected with the middle of the small-end connecting flange 1, and the rigid platform 5 swings relative to the small-end connecting.

The five-degree-of-freedom flexible continuum mechanical arm is formed by connecting two stages of structures in a parallel mode, and a first-stage mechanism is a three-degree-of-freedom tower-type corrugated pipe-shaped flexible body structure driven by fluid and tendon ropes in a mixed mode; the second-stage mechanism is a two-degree-of-freedom rapid adjustment rigid platform structure driven by a tendon rope. Preferably, the number of the bowden cable tendon ropes 4 and the steel wire rope tendon ropes 6 is 3. Three flexible bodies can realize the bending movement of the closed hollow tower type corrugated pipe-shaped flexible body 3, and generate coupling acting force with the change of internal fluid pressure, thereby leading the flexible body to generate large-amplitude bending deformation in any direction. The three bowden cable tendon ropes are symmetrically arranged on the outer side surface of the closed hollow tower type corrugated pipe shaped flexible body 3 in a 120-degree mode. As shown in fig. 1, a medium such as gas or liquid can be injected or extracted from the inside of the structure through the driving port 3-1, and the sealed hollow tower type bellows-shaped flexible body 3 is deformed such as extended or shortened according to the change of the internal fluid pressure.

Further, the material of the closed hollow tower type corrugated pipe shaped flexible body 3 is a polyurethane thermoplastic elastomer. The material has excellent wear resistance, excellent ozone resistance, high hardness, high strength, good elasticity, low temperature resistance and good performance. The closed hollow tower type corrugated pipe shaped flexible body is manufactured by 3D printing. 3D printing is favorable to rapid prototyping.

As shown in fig. 3, the middle of the rigid platform 5 is connected with the middle of the small end connecting flange 1 through a ball hinge 7. The three steel wire rope tendons are driven to apply corresponding pulling force, and the three steel wire rope tendons drive the rigid platform 5 to rotate around the ball hinge 7 in two degrees of freedom by changing the length.

Generally, the inside and outside surfaces of the closed hollow tower type bellows-like flexible body 3 are respectively covered with sealant layers. The air tightness treatment method of the hollow tower type corrugated pipe shaped flexible body comprises the following steps: defoaming treatment: pouring the sealant into a beaker, placing the beaker into a vacuum barrel, vacuumizing the vacuum barrel, and removing bubbles in the sealant; and (3) coating treatment: completely immersing the hollow tower type corrugated pipe-shaped flexible body (polyurethane thermoplastic elastomer) into a beaker containing the sealant after defoaming treatment, standing for 10 seconds, taking out the flexible body after standing from the beaker, and enabling the redundant sealant to naturally flow out from a driving interface to ensure that the inner surface and the outer surface of the flexible body are both covered by the sealant; and (3) drying treatment: and (3) placing the flexible body subjected to the filling treatment in a vacuum barrel for standing for 12 hours, and naturally drying the sealant to obtain the tower type corrugated pipe-shaped flexible body with good sealing property. Preferably, the sealant is a TPU sealant which is a reagent mainly used for synthesizing polyurethane resin with a special molecular structure and containing ester, ketone and benzene solvents. Is applied to micropore sealing and solves the problem of air tightness. Preferably, as shown in fig. 1 to 3, the cross section of the closed hollow tower type bellows-like flexible body 3 is conical. The conical structure is a circular ring in the circumferential direction, no dead angle exists, and the internal pressure is controlled uniformly and stably.

The present invention is not limited to the above embodiments, and those skilled in the art can make various changes and modifications without departing from the scope of the invention.

Claims

1. The five-degree-of-freedom flexible arm driven by fluid and tendon rope mixing is characterized in that: it comprises a secondary mechanism;

The first-level mechanism includes a small-end connecting flange (1), a large-end connecting flange (2), a closed hollow tower bellows-shaped flexible body (3) and at least three Bowden wire tendons (4);

The second-level mechanism includes a rigid platform (5) and at least three wire ropes and tendons (6);

A small end connecting flange (1) and a large end connecting flange (2) are respectively fixed on the small end and the large end of the closed hollow tower type bellows-shaped flexible body (3), and the closed hollow tower type bellows-shaped flexible body (3) A drive interface (3-1) for controlling the internal fluid pressure is opened on the large end face of the cable gland, and at least three Bowden wire tendons (6) are evenly distributed on the outer side of the closed hollow tower-type bellows-shaped flexible body (3) along the circumferential direction, and pass through The side ear channel (3-2) on the outer side of the airtight hollow tower-type bellows-shaped flexible body (3) is fixed at one end on the small-end connecting flange (1), and the other end passes through the large-end connecting flange (2) by the external drive device drive;

At least three steel wire rope tendons (6) are slid in the Bowden wire tendons (4) in one-to-one correspondence. The boarding tendon (4) is driven by an external driving device, the middle part of the rigid platform (5) is connected with the middle part of the small end connecting flange (1), and the rigid platform (5) swings relative to the small end connecting flange (1). .

2 . The five-degree-of-freedom flexible arm driven by mixing fluid and tendon according to claim 1 , characterized in that: the material of the airtight hollow tower bellows-shaped flexible body ( 3 ) is polyurethane thermoplastic elastomer. 3 .

3. The five-degree-of-freedom flexible arm driven by mixing fluid and tendon according to claim 1 or 2, characterized in that: the airtight hollow tower-type bellows-shaped flexible body (3) is made of 3D printing.

4. The five-degree-of-freedom flexible arm driven by mixing fluid and tendon according to claim 3, characterized in that: the middle part of the rigid platform (5) is connected to the small end connecting flange (1) through the ball hinge (7) Central connection.

5. The five-degree-of-freedom flexible arm driven by mixing fluid and tendon according to claim 4, characterized in that: the inner and outer surfaces of the airtight hollow tower-type bellows-shaped flexible body (3) are respectively covered with a sealant layer.

6. The five-degree-of-freedom flexible arm driven by mixing fluid and tendon according to claim 5, characterized in that the section of the closed hollow tower-type bellows-shaped flexible body (3) is conical.