CN111844125A - Compact and firm single-degree-of-freedom bionic joint and manufacturing method thereof - Google Patents

The invention discloses a compact and firm single-degree-of-freedom bionic joint and a manufacturing and driving method thereof, wherein the bionic joint comprises at least one first joint part, one second joint part and one connecting fiber; the end part of the first joint part is a convex curved surface, and the end part of the second joint part is a concave curved surface matched with the convex curved surface; the compact and firm single-degree-of-freedom bionic joint has the advantages of simple joint structure, small size, light weight, high strength and the like, and is high in impact resistance, and the stress of a connecting piece is reduced when the joint is bent; secondly, the compact and firm single-degree-of-freedom bionic joint has small clearance and high motion precision under the stress condition, and meanwhile, the whole bionic joint is convenient to manufacture by adopting an automatic process, so that the manufacturing efficiency is improved, and the manufacturing cost is reduced.

Compact and firm single-degree-of-freedom bionic joint and manufacturing method thereof

Technical Field

The invention relates to the technical field of robots, in particular to a compact and firm single-degree-of-freedom bionic joint and a manufacturing and driving method thereof.

Background

A joint is a common component in mechanical structures and its basic functions are: bearing radial force and tangential force, including bearing tensile force, pressure and torsional force; the freedom of mechanical movement is limited, i.e. the direction and extent of movement is limited.

The existing shaft sleeve type joint adopts a rigid shaft and a shaft sleeve as a design scheme, and has good joint stability and high motion precision. For example:

patentee DISNEY ENTERPRISES, INC. invention "ROBOT HAND WITH HUMAN-LIKEFINGERS" (US20100259057A 1);

patentee GM Global Technology Operations LLC invention "rotic thumbanalysis" (US 8424941);

patentee SQUSE Inc. invention "finger mechanism, robot hand and robot hand controlling method" (US10286561B 2);

the invention of the university of the Harbin industry of the patent entitled "finger joint of dexterous robot hand" (CN 101100063A);

the existing mechanical joint has the following defects:

first, the axle and axle sleeve bear pressure and pulling force simultaneously, for guaranteeing structural strength, the joint is bulky, manufacturing cost is high.

Secondly, mechanical structures comprising multiple joints, such as robot hands, shoulders and hip joints, have the defects of excessive space occupation, low space utilization rate and difficult part arrangement when auxiliary components such as connecting rods, sensors and the like are arranged at the joints.

Thirdly, the joint is made of hard material, and when the joint is impacted by external force, the local load is large, so that the material is easy to fatigue and deform, and further the failure of the component is caused.

The existing bionic joint tries to solve the problems and adopts a design mode of a joint curved surface and a connecting piece. For example:

'an artificial joint' invented by patentee Shanghai university (CN2565426Y)

' A bionic joint device with closed lubrication ' invented by patentee Zhao De Zheng ' (CN102152315B), (US20150127114A1)

'A multi-degree-of-freedom bionic joint' invented by the patent rights human Harbin engineering university (CN204546555U)

Paper Design of a high purity biomedical antibiotic and propofol incorporated into the lamb Regeneration

Paper A Compound biomedical Equipment Finger for Antropomorphic robotic hand via 3D Rapid Prototyping

And FLLEX Hand bionic manipulator of Korean IRIM Lab

The existing bionic joint has the following defects:

firstly, some adopt a deep ball socket scheme, so that a ball head rod is interfered with the edge of a ball socket, and the movement range of a joint is limited; and in addition, a shallow ball socket scheme is adopted, the connecting piece is in a sleeve shape or a sheet shape, the joint is unstable, the tensile capacity is weak, the joint head has large displacement, and the joint head is easy to separate from the joint socket.

Secondly, the joint connecting piece is made of softer weaving materials or other elastic materials, so that the joint is poor in stability, the joint is weak in tensile capacity, large gaps exist among the joints under the conditions of bearing tangential force, torsional force and tensile force, and the movement precision is poor.

Thirdly, the connecting piece is made of hard and tough sheet materials such as rubber sheets, when the joint rotates, the sheet materials bend, and the deformation generates resisting moment, consumes energy and causes poor movement flexibility.

Fourthly, the connecting piece and the structural piece are fixedly connected by adopting the modes of screws, surface bonding, annular clips and the like, and the connecting piece has low strength, poor tearing resistance and poor impact resistance.

Fifthly, the number of parts is large, the assembling and adjusting steps are large, the adoption of a standardized manufacturing process is not facilitated, the manufacturing cost is high, and the manufacturing efficiency is low.

Sixth, the FLLEX Hand bionic manipulator uses a rolling type joint, and the tensile resistance and the torsion resistance are small.

Disclosure of Invention

1. Technical problem to be solved

The invention aims to solve the technical problem of providing a compact and firm single-degree-of-freedom bionic joint and a manufacturing and driving method thereof, and performing structural optimization on the existing joint so as to increase the structural strength, increase the stability and the motion precision of the joint, reduce the stress of a connecting piece when the joint is bent, reduce the number of parts for manufacturing the joint and reduce the weight.

2. Technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: a compact and firm single-degree-of-freedom bionic joint comprises at least one first joint part, one second joint part and one connecting fiber; the end part of the first joint part is a convex curved surface, and the end part of the second joint part is a concave curved surface matched with the convex curved surface; the first joint part and the second joint part can be made of engineering plastics, light alloy or fiber reinforced composite materials, and can adopt a hollow form to reduce weight. The axis of the convex curved surface is provided with a first through hole, the edge of the concave curved surface is provided with a second through hole, and the connecting fibers respectively penetrate through the first through hole and the second through hole so as to realize that the second joint part rotates around the axis of the convex curved surface; the two ends of the added limiting fibers are respectively connected with the first joint part and the second joint part, the plane where the limiting fibers are located is coplanar with the rotating surface of the second joint part, and at the moment, the adaptive convex curved surface and concave curved surface, the connecting fibers and the limiting fibers jointly restrict the rotational freedom and the motion range of the second joint part, so that the second joint part can only rotate around the axis of the convex curved surface, and the second joint part has one degree of freedom; the two joint driving ropes are respectively connected to two sides of the second joint part or two sides of the first joint (1), and the joint driving ropes and the limiting fibers are coplanar.

The compact and firm single-degree-of-freedom bionic joint is characterized in that the connecting fibers and the limiting fibers are made of one or more of high-tensile-modulus tensile fibers and low-tensile-modulus elastic fibers. The high tensile modulus fiber bears the tensile force, the deformation is small when the stress is applied, and the joint precision is improved. The elastic fiber gives the pressure to the joint surface, and the prestress is favorable for eliminating the clearance of the joint surface, so that 2 joint surfaces are attached when the joint rotates, and the motion precision is improved. Low tensile modulus elastic fibers also impart good impact resistance to the joint. When the connecting piece made of the mixed fiber is not stressed, the high-tensile modulus fiber is in a relaxed state, when the connecting piece is stretched by an external force, the low-tensile modulus fiber is stressed and stretched, the high-tensile modulus fiber is tightened, and the connecting piece is not stretched any more. The connecting piece made of the mixed fiber has the outstanding advantages of keeping the flexibility of the joint, bearing larger tension and ensuring the movement precision of the joint. According to the use scene of the joint, the proportion of the two fibers can be flexibly selected, and the purposes of toughness, accuracy or softness and impact resistance are achieved. When the joint rotates, the fiber only needs to generate torsional motion, and the connection mode determines that the resistance stress generated when the joint rotates is small, the extra energy consumption is small, and the joint motion flexibility is high.

According to the compact and firm single-degree-of-freedom bionic joint, the surfaces of the convex curved surface and the concave curved surface are lubricated by one of a coating film, an insert or a coating lubricant so as to reduce the friction force generated when the second joint part rotates around the convex curved surface.

According to the compact and firm single-degree-of-freedom bionic joint, the two ends of the connecting fibers are subjected to surface treatment to increase the friction coefficient of the end parts, and the end parts of the connecting fibers are dispersed into fiber yarns. And two ends of the connecting fiber are fixed behind the resin module or the metal module and inserted into the corresponding mounting holes of the first joint and the second joint, so that the firmness of the connecting fiber can be obviously improved. Increasing the insertion depth of the connecting fibers, extending in the axial direction of the first articular component and the second articular component, may also increase the stiffness and rigidity of the connecting fibers.

In the compact and firm single-degree-of-freedom bionic joint, the middle part of the convex curved surface is provided with a groove parallel to the rotation surface of the second joint, and the middle part of the concave curved surface is provided with a ridge matched with the groove.

The compact and firm single-degree-of-freedom bionic joint comprises a convex curved surface, a concave curved surface and two connecting lines, wherein the middle part of the convex curved surface and the middle part of the concave curved surface are respectively provided with a groove; two ends of each connecting line are connected in the groove, and the two connecting lines, the first joint part and the second joint part form a four-bar mechanical structure, so that the second joint part is prevented from translating under tangential force while the joint rotation function is kept.

The compact and firm single-degree-of-freedom bionic joint is characterized in that the convex curved surface is one of a cylindrical surface, an elliptic cylindrical surface, a parabolic cylindrical surface, a cycloid cylindrical surface, an involute cylindrical surface, a saddle surface, an ellipsoid surface and a spherical surface.

In the compact and firm single-degree-of-freedom bionic joint, 1 joint driving rope adopts an elastic rope or a spring so as to reduce the number of drivers and the complexity of the mechanism.

The invention also discloses a compact and firm manufacturing method of the single-degree-of-freedom bionic joint, which comprises the following steps:

and 2, embedding the limiting fibers into the side surfaces of the first joint part and the second joint part respectively to form the bionic joint.

The invention also discloses a compact and firm driving method of the single-degree-of-freedom bionic joint, which comprises the following steps:

and 2, pulling the other end of one joint driving rope to realize the rotation of the second joint.

3. Advantageous effects

In conclusion, the beneficial effects of the invention are as follows:

(1) the compact and firm single-degree-of-freedom bionic joint has the advantages of simple joint structure, small volume, light weight, high strength and the like, has high impact resistance, and reduces the stress of a connecting piece when the joint is bent;

(2) the compact and firm single-degree-of-freedom bionic joint has small clearance and high motion precision under the stress condition, and meanwhile, the whole bionic joint is convenient to manufacture by adopting an automatic process, so that the manufacturing efficiency is improved, and the manufacturing cost is reduced.

Drawings

FIG. 1 shows a bionic joint with one degree of freedom;

FIG. 2, a groove or ridge provided in the first articular component and the second articular component;

FIG. 3 is a four bar linkage mechanism formed within the first and second articular components;

FIG. 4 is a schematic illustration of various connections for increasing the bonding strength of the connecting fibers to the first and second articular components;

FIG. 5 is a method for manufacturing a compact and firm grooving joint of a single-degree-of-freedom bionic joint;

FIG. 6 is a method for manufacturing a compact and firm stacked joint of a single-degree-of-freedom bionic joint;

FIG. 7 shows a method for manufacturing a compact and firm injection molding joint of a single-degree-of-freedom bionic joint.

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 described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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.

Example 1

Referring to fig. 1, fig. 1 is a side view showing a1 degree of freedom biomimetic joint.

The joint adopting the design has simple structure; small volume, light weight, high motion precision, excellent shock resistance and better weather resistance of the connecting piece.

Example 2

Referring to fig. 2, fig. 2 is a perspective exploded view (with the connector cut) showing an inner and outer reinforced 1 degree-of-freedom joint.

The following method is adopted to further restrict the motion range of the joint, reinforce the joint and increase the strength of the joint.

The joint adopting the design can bear larger tangential force.

Example 3

The joint adopting the design can bear larger tangential force, and can prevent the joint from translating when the joint is subjected to the tangential force while keeping the rotation function.

Example 4

Example 5

The joint adopting the design has the advantages of simple structure, no need of repeatedly perforating the fibers of the connecting piece, low winding difficulty and high impact resistance.

Example 6

The joint adopting the design has simple structure and high impact resistance.

Example 7

The joint adopting the design is convenient to manufacture by adopting an automatic process, the manufacturing efficiency is improved, and the manufacturing cost is reduced.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.