CN112109109B

CN112109109B - Flexible mechanical claw and mechanical arm thereof

Info

Publication number: CN112109109B
Application number: CN202010893416.6A
Authority: CN
Inventors: 苏伟; 李轶; 吕添; 彭旭东; 吴甲
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2021-09-28
Anticipated expiration: 2040-08-31
Also published as: CN112109109A

Abstract

The invention discloses a flexible mechanical claw and a mechanical arm thereof, wherein the mechanical claw comprises: the palm and more than two fingers connected with the palm by pins; each of the fingers includes: an inner jaw and an outer jaw; the inner claw comprises a base plate and a cross beam which are integrally formed; more than two crossbeams are positioned on the outer side surface of the substrate, and pin joints for connecting with the outer claws are arranged at the tops of the crossbeams and the end B of the substrate; the outer claw is an arc panel which is formed by more than two connecting sheets and is bent to set radian; each connecting sheet is respectively pinned between two adjacent cross beams or between the B end of the substrate and the adjacent cross beams; the inner claw and the outer claw of the mechanical claw are made of flexible materials with different hardness, and are combined with the mechanical structure design of the inner claw and the outer claw, so that the mechanical claw can well wrap a target object and has very firm grabbing characteristics.

Description

Flexible mechanical claw and mechanical arm thereof

Technical Field

The invention belongs to the technical field of intelligent robots, and particularly relates to a flexible mechanical claw and a mechanical arm thereof.

Background

The mechanical claw, as the name implies, is an instrument that can replace the human hand to perform a series of operations, and mainly consists of a hand and a mechanism for performing movements. To a certain extent, the device can grab and carry objects by a fixed program to replace heavy labor of people, can be utilized under the environment harmful to human bodies to protect the safety of human bodies, and is mainly applied to industrial departments such as mechanical manufacturing, metallurgy, light industry and the like.

Most of mechanical claws at the present stage have single target and generally only aim at one or two operation tasks. Again, the higher the flexibility of the gripper, the less damage to the target during operation. Thus, conventional rigid mechanical jaws have limited their own applications, while also increasing the relative manufacturing costs. The traditional mechanical claw is mostly made of metal materials, generally has rigid contact with a gripped object, lacks necessary flexibility, is unsafe for human-computer interaction, and greatly limits the universality and flexibility. Meanwhile, a large amount of mechanical joints of the traditional mechanical arm need to use lubricating oil, and the mechanical arm becomes an important technical gap in the development direction of oil feeding-free technology.

With the development of modern society, 3D printing technology and novel intelligent material develop maturity, and software gripper is as the fierce development of hot field. In the aspect of production cost, if a universal mechanical claw is adopted, one hand can be used for multiple purposes, and different types of operation can be realized by carrying the mechanical claw to different platforms. And because the gripper has the characteristics of reliable gripping, simple control, good environmental adaptability, strong self-adaptability, reliable, quick and accurate gripping and the like, the gripper becomes an ideal novel gripper development direction. In addition, the flexible structure has the advantages of no need of a large number of single parts for printing and assembling, simple operation and the like, so that the underactuated development direction is met. The design of the under-actuated bionic mechanical claw mainly lies in two aspects of bionic and under-actuated, and the number of driving motors is reduced while the flexibility of a human palm is achieved, so that the weight of the mechanical claw is reduced, and the control is simpler.

Therefore, the mechanical claw with diversity, strong universality, high stability and excellent flexibility is designed, and the mechanical claw has great significance. However, the flexible mechanical claws appearing in recent years have more or less defects in the aspects of the bending degree of the mechanical claws, the fitting degree with a target object, the operation stability and durability of the mechanical claws, the maximum load capacity, the strength of joint joints and the development of underactuation.

Disclosure of Invention

In view of the above, the invention provides a flexible mechanical gripper and a mechanical arm thereof, wherein an inner gripper and an outer gripper of the mechanical gripper are made of flexible materials with different hardness, and the mechanical structure design of the inner gripper and the outer gripper is combined, so that the mechanical gripper can well wrap a target object and has very firm gripping characteristics.

The invention is realized by the following technical scheme:

a flexible gripper, comprising: the palm and more than two fingers connected with the palm by pins;

the palm includes: the driving mechanism comprises a first plate, a second plate, a driving shaft and a driving mechanism;

the first and second plates are arranged in parallel; the driving shaft sequentially penetrates through the centers of the first plate and the second plate, one end of the driving shaft is fixedly connected with the first plate, and the other end of the driving shaft is connected with the driving mechanism; when the driving mechanism drives the driving shaft to move along the axial direction of the driving shaft, the first plate is further driven to move along the axial direction of the driving shaft, so that the distance between the first plate and the second plate is changed;

each of the fingers includes: an inner jaw and an outer jaw;

the inner claw comprises a base plate and a cross beam which are integrally formed; the substrate is of a rectangular plate-shaped structure; two opposite side surfaces of the substrate are respectively an outer side surface and an inner side surface, and two ends in the length direction are respectively an A end and a B end; the more than two crossbeams are positioned on the outer side surface of the substrate, have different heights and are uniformly distributed at intervals of a set distance from the end A of the substrate to the end B of the substrate according to the sequence of sequentially decreasing heights; pin joints for connecting with the outer claws are arranged at the top of the cross beam and the end B of the base plate;

the outer claw is an arc panel which is formed by more than two connecting sheets and is bent to set radian; each connecting sheet is an arc-shaped plate with a set bent radian, more than two connecting sheets are arranged in parallel and are connected into an outer claw through a pin shaft;

each connecting sheet is respectively pinned between two adjacent cross beams or between the B end of the substrate and the adjacent cross beams;

wherein the inner claw is made of a silica gel material; the outer claw is made of TPU material;

more than two fingers are respectively connected with the palm by pins, and the specific mode of the pin connection is as follows:

the bottom of a cross beam of the inner claw of each finger, which is positioned at the end part of the A end, is in pin joint with one side edge of the first plate, and the top of the cross beam is in pin joint with one side edge of the second plate through a connecting plate; wherein, the connecting plate all passes through the round pin axle pin joint with the top of crossbeam and a side of second board.

Furthermore, the first plate and the second plate are both regular hexagon plates, the side length of the first plate is smaller than that of the second plate, and six sides of the first plate and the second plate are respectively parallel in a one-to-one correspondence manner;

the first plate and the second plate are both made of metal materials.

Further, the driving mechanism adopts an air storage tank, a vacuum valve or a small-sized air pump.

Furthermore, the inner side surface of the base plate of the inner claw is covered with an anti-slip strip.

Further, more than two beams are respectively: a base beam and more than two connecting beams; the base cross beam is a flat plate, and the connecting cross beam is a plate-shaped structure with a raised middle part of two opposite side surfaces, namely a plate-shaped structure with a rhombic cross section; the heights of more than two connecting crossbeams are different; the base cross beam is positioned on the end A of the substrate; more than two connecting beams are uniformly arranged at intervals of a set distance from the end A of the substrate to the end B of the substrate according to the sequence that the heights are sequentially decreased.

Further, the connecting piece is cut from the spherical shell.

Further, the number of fingers is set according to the shape of the object to be grabbed, and if the object to be grabbed is a spherical entity, three fingers are adopted for grabbing; and if the object to be grabbed is a cylinder, grabbing by using two fingers.

A flexible robotic arm comprising: an arm body and the gripper;

the arm body includes: wrist, forearm, elbow and shoulder joints;

the mechanical claw is arranged at the front end of the small arm through a wrist joint, the rear end of the small arm is connected with the front end of the large arm through an elbow joint, and the rear end of the large arm is arranged on an external supporting component through a shoulder joint; wherein, a support plate is fixed on the second plate of the mechanical claw and is arranged on the wrist joint;

the wrist joint has three degrees of freedom of rotation;

the elbow joint and the shoulder joint both adopt double-inclined-plane bionic joints and have two-degree-of-freedom rotation;

the small arm and the large arm are both sleeve telescopic devices.

Has the advantages that:

(1) the flexible mechanical claw adopts a scheme of combining a mechanical structure and a flexible material, namely, a mechanical pin joint mode is adopted at the joint of the inner claw, the outer claw and the palm, and the inner claw and the outer claw are made of flexible materials with different hardness, so that the flexible mechanical claw has good grabbing capacity, and the problem that the joint of the outer claw is easy to break under the condition of large load is solved.

(2) The inner claw and the outer claw are made of flexible materials with different hardness, namely the inner claw is made of a softer flexible material, the outer claw is made of a harder flexible material, so that the inner claw of the flexible mechanical claw can better grab an object and reduce the damage to the object, and meanwhile, the material change of the outer claw enhances the stability of the grabbing capacity of the mechanical claw.

(3) The inner claw is provided with the anti-slip strip, and the outer claw adopts an arc panel which is formed by more than two connecting sheets and is bent to set radian; and every the connection piece is the crooked arc of setting for the radian, and above-mentioned structure can strengthen the snatching steadiness of gripper, and prevents that the finger from turning up, further promotes the biggest quality of snatching.

(4) The first plate and the second plate are made of regular hexagon plates, two fingers or three fingers can be arranged due to the multi-symmetry of the regular hexagons, and the adaptability of the mechanical claw to an object to be grabbed is improved by flexibly changing the grabbing structure of the mechanical claw.

(5) The mechanical arm adopts the sleeve telescopic device and is connected by the double-inclined-surface bionic joint, so that the occupied space is small, the flexibility of the space is higher than that of the common traditional mechanical arm, and the total weight of the mechanical arm is smaller; the maximization of the degree of freedom of the whole mechanical arm is achieved through the combination of multiple groups of same structures.

In a word, the mechanical claw and the mechanical arm thereof have the characteristics of stable grabbing, no eversion and large grabbing load, can conveniently and flexibly change the number of fingers, and have wide application prospect.

Drawings

FIGS. 1 to 2 are structural composition diagrams of example 1;

FIG. 3 is a schematic structural view of the inner jaw;

FIG. 4 is a schematic structural view of the outer jaw;

FIGS. 5 to 7 are structural composition diagrams of example 2;

wherein, 1-inner claw, 2-outer claw, 2-1-connecting piece, 3-beam, 3-1-base beam, 3-2-connecting beam, 4-palm, 4-1-first plate, 4-2-second plate, 5-antislip strip, 6-driving shaft, 8-connecting plate, 9-wrist joint, 10-forearm, 11-forearm, 12-elbow joint and 13-shoulder joint.

Detailed Description

The invention is described in detail below by way of example with reference to the accompanying drawings.

Example 1:

the present embodiment provides a flexible gripper, see fig. 1-2, comprising: the palm 4 and more than two fingers connected with the palm 4 by pins;

the palm 4 includes: a first plate 4-1, a second plate 4-2, a drive shaft 6 and a drive mechanism;

the first plate 4-1 and the second plate 4-2 are both regular hexagon plates, the side length of the first plate 4-1 is smaller than that of the second plate 4-2, and the first plate 4-1 and the second plate 4-2 are both made of metal materials;

the first plate 4-1 and the second plate 4-2 are arranged in parallel, and six side edges of the first plate 4-1 and the second plate 4-2 are respectively in one-to-one correspondence parallel; the driving shaft 6 sequentially penetrates through the centers of the first plate 4-1 and the second plate 4-2, one end of the driving shaft 6 is fixedly connected with the first plate 4-1, and the other end of the driving shaft 6 is connected with the driving mechanism; when the driving mechanism drives the driving shaft 6 to move along the axial direction of the driving shaft, the first plate 4-1 is further driven to move along the axial direction of the driving shaft 6, so that the distance between the first plate 4-1 and the second plate 4-2 is changed; the driving mechanism drives the driving shaft 6 to move in a pneumatic mode, and because the mechanical claw in the embodiment does not relate to the use environment of a large air pump device, the driving mechanism adopts an air storage tank, a vacuum valve or a small air pump;

each of the fingers includes: an inner jaw 1 and an outer jaw 2;

referring to fig. 3, the inner jaw 1 comprises a base plate and a cross beam 3 which are integrally formed; the substrate is of a rectangular plate-shaped structure, and the length of the substrate is 190 mm; two opposite side surfaces of the substrate are respectively an outer side surface and an inner side surface, and two ends in the length direction are respectively an A end and a B end; the inner side surface of the base plate is covered with an anti-slip strip 5, and the anti-slip strip 5 is used for improving the firmness of the mechanical claw in grabbing an object; more than two cross beams 3 are positioned on the outer side surface of the substrate;

the two or more cross beams 3 are respectively: a base beam 3-1 and more than two connecting beams 3-2; the base crossbeam 3-1 is a flat plate, and the connecting crossbeam 3-2 is a plate-shaped structure with a raised middle part of two opposite side surfaces, namely a plate-shaped structure with a rhombic cross section; the heights of more than two connecting cross beams 3-2 are different; the base crossbeam 3-1 is positioned on the end A of the substrate; more than two connecting beams 3-2 are uniformly distributed at intervals of a set distance from the end A of the substrate to the end B of the substrate according to the descending order of the height, and the set distance is 17 mm; the top of the base cross beam 3-1, the top of each connecting cross beam 3-2 and the end B of the base plate are provided with pin joints for connecting with the outer claws 2;

referring to fig. 4, the outer claw 2 is an arc panel which is formed by more than two connecting sheets 2-1 and is bent to set a radian; each connecting piece 2-1 is an arc-shaped plate with a set bent radian, and more than two connecting pieces 2-1 are arranged in parallel and are connected into an outer claw 2 through a pin shaft; the connecting piece 2-1 is obtained by cutting a spherical shell, the outer diameter of the spherical shell is 100mm, and the inner diameter of the spherical shell is 95 mm;

each connecting piece 2-1 is respectively positioned between two adjacent connecting beams 3-2, between the base beam 3-1 and the adjacent connecting beam 3-2 or between the B end of the substrate and the adjacent connecting beam 3-2; two connecting sheets 2-1 positioned at two ends of the outer claw 2 are respectively in pin joint with a corresponding base cross beam 3-1 and a pin joint at the B end of the base plate through pin shafts, and the joint of two adjacent connecting sheets 2-1 is respectively in pin joint with a corresponding pin joint of the connecting cross beam 3-2 through pin shafts, so that the connection of one inner claw 1 and one outer claw 2 is realized; the connecting parts are connected by pins, so that the problem that the maximum grabbing capacity of the mechanical claw is influenced because the connecting parts are easy to break under the condition of large load is solved; the diameters of the pin holes at all the pin joints are 1 mm;

the inner claw 1 is made of softer flexible material, preferably silica gel material; the structure of the connecting beam 3-2 of the inner claw 1 can maintain the structural stability to the maximum extent, and simultaneously, the outer claw 2 can be better deformed correspondingly under the bending pressure of the substrate of the inner claw 1; the outer claws 2 are made of hard and flexible materials, preferably flexible TPU materials; the structure and the material of the outer claw 2 can play a role in enhancing the grabbing stability, prevent the mechanical claw unit from turning outwards and further improve the maximum grabbing quality;

more than two fingers are respectively connected with the palm 4 by pins, and the specific mode of the pin connection is as follows:

the bottom of the base cross beam 3-1 of the inner claw 1 of each finger is in pin joint with one side edge of the first plate 4-1, and the top of the base cross beam 3-1 of the inner claw 1 is in pin joint with one side edge of the second plate 4-2 through the connecting plate 8; the connecting plate 8 is connected with the top of the base cross beam 3-1 and one side edge of the second plate 4-2 through pin shafts;

setting the number of fingers according to the shape of an object to be grabbed, if the object to be grabbed is a sphere-like entity, grabbing by using three fingers, wherein the three fingers are respectively connected to three sides of a first plate 4-1 and a second plate 4-2 which are not adjacent to each other and are arranged at intervals; if the object to be grabbed is a cylinder or other types of cylinders, grabbing by using two fingers, wherein the two fingers are respectively connected to two opposite parallel side edges of the first plate 4-1 and the second plate 4-2 of the regular hexagon;

the working principle is as follows: the driving mechanism drives the first plate 4-1 to move axially along the driving shaft 6 through the driving shaft 6, so that the distance between the first plate 4-1 and the second plate 4-2 is changed, and more than two fingers are driven to open and close;

when the distance between the first plate 4-1 and the second plate 4-2 becomes smaller, more than two fingers are closed, thereby clamping the object; in the process of clamping an object, because the inner claw 1 is made of a softer flexible material, the inner claw 1 deforms correspondingly according to the shape of the object to be clamped, so that the object is prevented from being damaged; the inner claw 1 is provided with the anti-slip strips 5, so that the firmness of the mechanical claw in grabbing objects can be improved; because the outer claw 2 is formed by more than two connecting sheets 2-1 through pin joint and has a plurality of degrees of freedom, when the inner claw 2 deforms, the bending angle of the outer claw 2 can be automatically adjusted, and the movement interference with the inner claw 1 is prevented;

when the distance between the first panel 4-1 and the second panel 4-2 becomes larger, more than two fingers are gradually opened, thereby gradually releasing the object which has been clamped.

Example 2:

the present embodiment provides a flexible robotic arm, see fig. 5-7, comprising: the gripper and arm of example 1;

the arm body includes: a wrist joint 9, a small arm 10, a large arm 11, an elbow joint 12 and a shoulder joint 13;

the mechanical claw is arranged at the front end of a small arm 10 through a wrist joint 9, the rear end of the small arm 10 is connected with the front end of a big arm 11 through an elbow joint 12, and the rear end of the big arm 11 is arranged on an external supporting component through a shoulder joint 13; wherein, a supporting plate is fixed on the second plate 4-2 of the mechanical claw and is arranged on the wrist joint 9;

the wrist joint 9 has three degrees of freedom of rotation;

the elbow joint 12 and the shoulder joint 13 both adopt double-inclined-plane bionic joints and have two-degree-of-freedom rotation;

the small arm 10 and the large arm 11 are sleeve telescopic devices;

the working principle is as follows: the mechanical arm can drive the mechanical claw on the mechanical arm to move to the place where the object to be grabbed is located, and the object is grabbed through the mechanical claw.

In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A flexible gripper, comprising: the palm (4) and more than two fingers which are in pin joint with the palm (4);

the palm (4) comprises: a first plate (4-1), a second plate (4-2), a drive shaft (6) and a drive mechanism;

the first plate (4-1) and the second plate (4-2) are arranged in parallel; the driving shaft (6) sequentially penetrates through the centers of the first plate (4-1) and the second plate (4-2), one end of the driving shaft (6) is fixedly connected with the first plate (4-1), and the other end of the driving shaft (6) is connected with the driving mechanism; when the driving mechanism drives the driving shaft (6) to move along the axial direction of the driving shaft, the first plate (4-1) is further driven to move along the axial direction of the driving shaft (6), so that the distance between the first plate (4-1) and the second plate (4-2) is changed;

each of the fingers includes: an inner jaw (1) and an outer jaw (2);

the inner claw (1) comprises a base plate and a cross beam (3) which are integrally formed; the substrate is of a rectangular plate-shaped structure; two opposite side surfaces of the substrate are respectively an outer side surface and an inner side surface, and two ends in the length direction are respectively an A end and a B end; the more than two crossbeams (3) are positioned on the outer side surface of the substrate, the more than two crossbeams (3) have different heights and are uniformly distributed at intervals of a set distance from the end A of the substrate to the end B of the substrate according to the sequence of sequentially decreasing heights; the top of the cross beam (3) and the end B of the base plate are provided with pin joints for connecting with the outer claws (2);

the outer claw (2) is an arc panel which is formed by more than two connecting sheets (2-1) and is bent to set radian; each connecting piece (2-1) is an arc-shaped plate with a set bent radian, and more than two connecting pieces (2-1) are arranged in parallel and are connected into an outer claw (2) through a pin shaft;

each connecting piece (2-1) is respectively pinned between two adjacent cross beams (3) or between the end B of the base plate and the adjacent cross beam (3);

wherein the inner claw (1) is made of a silica gel material; the outer claw (2) is made of TPU material;

more than two fingers are respectively connected with the palm (4) in a pin joint mode in the following specific mode:

the bottom of a cross beam (3) of the inner claw (1) of each finger at the end of the A end is in pin joint with one side edge of the first plate (4-1), and the top of the cross beam (3) is in pin joint with one side edge of the second plate (4-2) through a connecting plate (8); wherein, the connecting plate (8) is connected with the top of the beam (3) and one side edge of the second plate (4-2) through pin shafts.

2. A flexible gripper according to claim 1, characterised in that the first plate (4-1) and the second plate (4-2) are both regular hexagonal plates, and the first plate (4-1) has a smaller side length than the second plate (4-2), and six sides of the first plate (4-1) and the second plate (4-2) are parallel one to one;

the first plate (4-1) and the second plate (4-2) are made of metal materials.

3. The flexible gripper of claim 1, wherein said drive mechanism comprises an air reservoir, a vacuum valve, or a small air pump.

4. A flexible mechanical claw according to claim 1, characterised in that the inner side of the base plate of the inner claw (1) is covered with anti-slip strips (5).

5. A flexible gripper according to claim 1, characterised in that two or more of said beams (3) are respectively: a base beam (3-1) and more than two connecting beams (3-2); the base cross beam (3-1) is a flat plate, and the connecting cross beam (3-2) is a plate-shaped structure with a raised middle part of two opposite side surfaces, namely a plate-shaped structure with a rhombic cross section; the heights of more than two connecting cross beams (3-2) are different; the base cross beam (3-1) is positioned on the end A of the substrate; more than two connecting beams (3-2) are uniformly arranged at intervals of a set distance from the end A of the substrate to the end B of the substrate according to the sequence of descending the height in turn.

6. A flexible gripper according to claim 1, characterised in that the connecting piece (2-1) is cut out of a spherical shell.

7. The flexible mechanical claw according to claim 1, wherein the number of fingers is set according to the shape of the object to be grasped, and if the object to be grasped is a spherical solid, three fingers are used for grasping; and if the object to be grabbed is a cylinder, grabbing by using two fingers.

8. A flexible robotic arm, comprising: an arm body and the gripper of claim 1;

the arm body includes: a wrist joint (9), a small arm (10), a big arm (11), an elbow joint (12) and a shoulder joint (13);

the mechanical claw is arranged at the front end of a small arm (10) through a wrist joint (9), the rear end of the small arm (10) is connected with the front end of a big arm (11) through an elbow joint (12), and the rear end of the big arm (11) is arranged on an external supporting component through a shoulder joint (13); wherein, a supporting plate is fixed on a second plate (4-2) of the mechanical claw and is arranged on a wrist joint (9);

the wrist joint (9) has three degrees of freedom of rotation;

the elbow joint (12) and the shoulder joint (13) both adopt double-inclined-plane bionic joints and have two-degree-of-freedom rotation;

the small arm (10) and the large arm (11) are both sleeve telescopic devices.