CN112476473A

CN112476473A - Flexible mechanical gripper

Info

Publication number: CN112476473A
Application number: CN202011292094.6A
Authority: CN
Inventors: 张文妍; 李成刚
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2020-11-18
Filing date: 2020-11-18
Publication date: 2021-03-12

Abstract

The invention discloses a flexible mechanical paw, which comprises a fixed spherical crown, a plurality of finger parts extending from the fixed spherical crown, a lifting device and a connecting piece, wherein a cylinder device drives a small cross beam to drive a thin-wall ring to control the finger parts to open and retract by moving a piston up and down in a cylinder barrel, the fixed spherical crown is made of rigid materials, the finger parts are fixedly connected with the fixed spherical crown, the paw part is made of flexible thin steel wires as a framework, and silica gel and other materials are used as a skin. The device controls the finger parts to open and retract through the air cylinder, is simple to operate, and is suitable for grabbing and clamping irregular objects with small mass.

Description

Flexible mechanical gripper

Technical Field

The invention relates to the technical field of robots, in particular to a mechanical gripper.

Background

With the deep application of the robot technology in the fields of high-end manufacturing industry, service industry, medical care industry and the like, tasks such as flexible grabbing, interactive blending and the like provide higher challenges for the design of robot grabbing. Some articles in life, such as apples and pears, have the characteristics of irregular shapes, inconsistent geometric sizes, random grabbing pose, easy damage to skins and the like of target objects. The grabbing device is required to have flexibility and adaptability in the automatic boxing and taking processes, and not only can grab objects without damaging the objects, but also can grab objects stably and reliably. In view of the above problems, it is desirable to provide a flexible mechanical gripper which can stably and reliably grasp an object which is easily damaged and has an irregular shape.

The invention patent with Chinese patent application number 201810097076.9 proposes a pneumatic soft gripper with loading capacity, but the soft gripper has complicated finger structure, difficult control of the matching of finger joints, and may cause problems of unreliable and unstable gripping due to limited enveloping range. The invention patent with the Chinese patent application number of 201910841727.5 provides a clamping device for grabbing irregular objects such as fruits, vegetables and marine products, but the clamping device of the soft robot has the disadvantages of high material cost, high assembly difficulty and difficult matching of jellyfish-shaped ring muscles and longitudinal muscles.

For this reason, a new technical solution is needed to solve the above technical problems.

Disclosure of Invention

In order to solve the problems, the invention provides a flexible mechanical gripper which is used for solving the problem of how to stably and reliably grip an easily damaged and irregular target object.

In order to achieve the purpose, the flexible mechanical gripper provided by the invention adopts the following technical scheme:

a flexible mechanical paw comprises a fixed spherical crown, a plurality of finger parts extending from the fixed spherical crown, a lifting device and a connecting piece; the finger part is sleeved with a soft outer sleeve, and the soft outer sleeve is connected and fixed with the connecting piece; the lifting device is connected with the connecting piece and drives the connecting piece and the soft outer sleeve to move up and down; when the lifting device drives the connecting piece to move upwards, the part of the finger part, which is positioned outside the connecting piece, turns upwards.

Further, the finger parts are arc-shaped in a natural state, and the arc-shaped state is as follows: the middle portions of the fingers expand outwardly and the bottom ends of the fingers contract inwardly.

Further, the soft outer sleeve part fixed with the connecting piece is positioned at the position close to the middle of the finger part.

Furthermore, the finger parts adopt flexible thin steel wires.

Further, soft overcoat is the silica gel material and entangles finger portion completely, and the part that soft overcoat and connecting piece are connected is an ascending bulge.

Further, the connecting piece is the lateral wall that extends downwards, fixed spherical crown is located the inside of lateral wall, and finger portion outwards extends downwards from the inside of lateral wall.

Has the advantages that: the finger parts of the flexible mechanical claw provided by the invention can be opened, namely when the lifting device drives the connecting piece to move upwards, the parts of the finger parts, which are positioned on the outer side of the connecting piece, are turned upwards to form an opened state. In addition, when the finger parts are in a free state (for example, the connecting pieces move downwards so that the finger parts are not stressed by the pressure of the connecting pieces), the finger parts are in a state that the bottom ends of the finger parts shrink inwards, so that circular and irregular objects can be grabbed through the matching of the plurality of finger parts. Meanwhile, the object can be guaranteed not to be damaged, and the grabbing is more flexible, reliable and stable. Meanwhile, the paw is simple in structure and small in size.

Drawings

Fig. 1 is a schematic view of the structure of the flexible gripper of the present invention, and shows a state where the fingers are in a free state for gripping.

FIG. 2 is a schematic diagram of the flexible gripper of the present invention, showing the fingers in an open position.

Detailed Description

Referring to fig. 1 and 2, the present invention discloses a flexible mechanical gripper, which includes a fixed spherical crown 400, a plurality of fingers 501 extending from the fixed spherical crown 400, a lifting device, and a connecting member 300. The finger 501 is sleeved with a soft casing 502, and the soft casing 502 is connected and fixed with the connector 300. The connection member 300 is fixed to the lifting performing end of the lifting apparatus by the cross member 200. The lifting device 100 drives the connecting member 300 and the soft outer sleeve 502 to move up and down. In the present embodiment, the fixed spherical cap 400 is rigid and fixed while the link 300 moves, that is, the link 300 moves up and down with respect to the fixed spherical cap 400. In this embodiment, the lifting device 100 is a cylinder device, and includes a cylinder 101, a piston 102, and a connecting cylinder 103 connected to a lower end of the cylinder 101, wherein the connecting cylinder 103 is fixed to the fixed spherical crown 400; and the rod delivery end of the piston 102 is connected to the connector 300.

When the lifting device drives the connecting member 300 to move upward, the connecting portion of the soft outer sleeve 502 fixed to the connecting member 300 and the portion of the finger portion 501 located at the connecting portion also move upward, and the portion of the finger portion connected to the fixed spherical cap 400 is fixed, so as shown in fig. 2, when the connecting member 300 and the soft outer sleeve 502 continuously rise, the portion of the finger portion 501 located outside the connecting member 300 is turned upward under the pressure of the connecting member. In this state, the fingers 501 are open, i.e. ready to grasp an article. In contrast, when the finger portion 501 is in a free state, in the present embodiment, as shown in fig. 1, when the finger portion 501 is in an open state, the connector 300 is driven by the lifting device to move downward, so that the finger portion 501 is no longer pressed by the connector 300, and at this time, the finger portion 501 is in a state of shrinking inward at the bottom end, so that the circular and irregular-shaped object 600 can be grasped by matching the plurality of finger portions.

In order to facilitate the gripping of the finger 501 in its free state, the bottom ends of the fingers are retracted inwardly, which is also a common configuration of gripping fingers. In the present embodiment, the finger portion 501 is preferably configured to be in an arc shape in a natural state, and the arc shape is preferably configured to be in a state of: the middle parts of the finger parts 501 are expanded outwards, and the bottom ends of the finger parts are contracted inwards, so that the space surrounded by the plurality of finger parts 501 is spherical or spheroidal, and irregular objects 600 such as fruits and the like can be grabbed more conveniently. And the finger 501 is made of flexible thin steel wire and has elasticity. The soft outer sleeve 502 is made of silica gel and completely covers the finger part 501, and the part of the soft outer sleeve 502 connected with the connecting piece 300 is an upward protruding part 503.

In order to facilitate the fingers 501 to smoothly open when pressed by the connector 300, the soft cover portion fixed to the connector 300 is located at a position near the middle of the fingers in the present embodiment. The connector 300 is a downwardly extending sidewall and the fixed spherical cap is located inside the sidewall with the fingers extending outwardly and downwardly from the inside of the sidewall.

The invention embodies a number of methods and approaches to this solution and the foregoing is only a preferred embodiment of the invention. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention. All the components not specified in the present embodiment can be realized by the prior art.

Claims

1. A flexible mechanical gripper is characterized in that: comprises a fixed spherical crown, a plurality of finger parts extending from the fixed spherical crown, a lifting device and a connecting piece; the finger part is sleeved with a soft outer sleeve, and the soft outer sleeve is connected and fixed with the connecting piece; the lifting device is connected with the connecting piece and drives the connecting piece and the soft outer sleeve to move up and down; when the lifting device drives the connecting piece to move upwards, the part of the finger part, which is positioned outside the connecting piece, turns upwards.

2. The flexible manipulator according to claim 1, wherein: the finger part is arc-shaped in a natural state, and the arc-shaped state is as follows: the middle portions of the fingers expand outwardly and the bottom ends of the fingers contract inwardly.

3. The flexible manipulator according to claim 2, wherein: the soft outer sleeve part fixed with the connecting piece is positioned at the position close to the middle of the finger part.

4. The flexible manipulator according to claim 3, wherein: the finger parts adopt flexible thin steel wires.

5. The flexible manipulator according to claim 4, wherein: soft overcoat is the silica gel material and entangles finger portion completely, and the part that soft overcoat and connecting piece are connected is an ascending bulge.

6. The flexible manipulator according to claim 1, wherein: the connecting piece is the lateral wall that downwardly extending, fixed spherical crown is located the inside of lateral wall, and finger portion outwards extends downwards from the inside of lateral wall.