CN111761595A

CN111761595A - Self-adaptive hand driven by SMA and rope in combined mode

Info

Publication number: CN111761595A
Application number: CN202010468059.9A
Authority: CN
Inventors: 龙樟; 荣明杰; 杨启超; 张洋; 冯文荣; 梁春平
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2020-05-28
Filing date: 2020-05-28
Publication date: 2020-10-13
Anticipated expiration: 2040-05-28
Also published as: CN111761595B

Abstract

The invention discloses a self-adaptive hand driven by SMA and a rope in a composite mode, which comprises a palm seat, a plurality of finger bodies arranged on the palm seat and a finger body driving mechanism used for driving the finger bodies to fold and reset, wherein the finger bodies are arranged on the palm seat; the finger body comprises a plurality of finger joints which are sequentially hinged, a support column which is fixedly arranged on each finger joint and a pulley which is arranged at a hinge shaft between two adjacent finger joints; the finger body driving mechanism comprises a shape memory alloy wire, a recovery rope, a power-on device for powering on the shape memory alloy wire to contract the shape memory alloy wire, and a recovery driving device for pulling the recovery rope; the flexible finger driving structure of the gripper has the characteristics of light weight and flexibility, and compared with the traditional structure, the flexible finger driving structure has the advantages of small volume, light weight, flexible movement and good environmental adaptability, and overcomes the defects of the traditional rigid flexible hand.

Description

Self-adaptive hand driven by SMA and rope in combined mode

Technical Field

The invention relates to the field of mechanical claws, in particular to a self-adaptive hand driven by SMA and a rope in a composite mode.

Background

The mechanical gripper as a terminal manipulator of the robot is one of the very important components in the robot system, and directly determines the controllability and the intelligence level of the robot. The existing mechanical gripper is generally designed aiming at completing specific tasks in specific working environments, has single gripping function and poor universality and flexibility, and is difficult to meet the requirement of various complex operations on flexible production lines for gripping various workpieces. Therefore, the multi-finger humanoid flexible hand with the modern engineering practical application becomes an important research point in the robot field.

In view of the flexible hand of the robot which is put into use in industry at present, the flexible hand is mostly made of rigid materials, and the driving mode generally adopts the modes of motors, pneumatics, hydraulics and the like. The traditional rigid claw has strong stability and reliability, but has the defects of complex structure, heavy weight, poor flexibility and the like. In order to eliminate the influence caused by many factors of the traditional rigid structure and driving mode, scholars at home and abroad are always searching for intelligent bionic materials to realize lightweight and flexible design of flexible hands, such as shape memory alloys, electroactive polymers, response hydrogel and other intelligent materials. Compared with the traditional flexible hand made of intelligent materials or driven, the flexible hand has the advantages of small volume, light weight, flexible movement and good environmental adaptability, and overcomes the defects of the traditional rigid flexible hand.

Therefore, the self-adaptive gripper is designed, the problems of single specific design function, large size, poor flexibility and the like of the traditional gripper are expected to be solved, the application range limitation of the traditional mechanical gripper is broken through, and the application and development of the robot are promoted.

Disclosure of Invention

The invention relates to an adaptive hand driven by SMA and rope in a composite mode, which comprises a palm seat, a plurality of finger bodies arranged on the palm seat and a finger body driving mechanism used for driving the finger bodies to fold and reset; the finger body comprises a plurality of finger joints which are sequentially hinged, a support column which is fixedly arranged on each finger joint and a pulley which is arranged at a hinge shaft between two adjacent finger joints; the finger body driving mechanism comprises a shape memory alloy wire, a recovery rope, a power-on device for powering on the shape memory alloy wire to contract the shape memory alloy wire, and a recovery driving device for pulling the recovery rope; the outer end of the recovery rope is fixed on the support columns of the outermost knuckles of the finger body, the inner end of the recovery rope is connected to the recovery driving device, and the middle part of the recovery rope is in contact with the support columns of all knuckles; the outer end of the shape memory alloy wire is fixed on the support columns of the outermost knuckles of the finger body, the other end of the shape memory alloy wire is connected to the electrifying device, and the middle part of the shape memory alloy wire sequentially bypasses the support columns and the pulleys;

furthermore, a reciprocating circuitous guide groove is arranged in the palm seat, and the shape memory alloy wire is connected to the electrifying device through the guide groove.

Further, the restoring driving device is an electromagnet device arranged in the palm seat; the electromagnet device comprises a magnet box base fixed in the palm base, an electromagnet, an iron sheet and a magnet box cover fixed on the magnet box base; the inner end of the recovery rope is fixed on the iron sheet; the magnet box base is provided with a sliding groove for guiding the sliding of the iron sheet and a magnet mounting position for fixedly mounting the electromagnet.

Furthermore, the number of the finger bodies is three, namely two long fingers and one short finger; the long finger comprises four knuckles; the short finger comprises three knuckles.

Furthermore, a plurality of columns used for fixing shape memory alloy wires or guiding the rope to change direction are arranged in the finger seat.

The invention has the beneficial effects that: in the gripper structure, the shape memory alloy wire is used for driving the finger body to bend to realize gripping action, the electromagnet is used for pulling the recovery rope to realize finger body resetting, and the flexible finger driving structure has the characteristics of light weight and flexibility.

Drawings

The invention is further described below with reference to the following figures and examples:

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic structural diagram of a short finger according to the present invention;

FIG. 3 is a schematic structural view of a long finger according to the present invention;

FIG. 4 is a bottom view of the palm rest top cover of the present invention;

FIG. 5 is a bottom view of the support plate of the present invention;

FIG. 6 is a schematic diagram of the construction of an electromagnet of the present invention;

FIG. 7 is a schematic structural diagram of a magnet box base according to the present invention;

FIG. 8 is a schematic view of the finger body drive mechanism of the present invention;

fig. 9 is a force-bearing schematic diagram of the finger body supporting column of the present invention.

Detailed Description

As shown in fig. 1, the adaptive hand driven by the SMA and the rope in combination according to the embodiment includes a palm seat, three finger bodies arranged on the palm seat, and a finger body driving mechanism for driving the finger bodies to fold and reposition;

in this embodiment, the number of the finger bodies is three, namely two long fingers 2 and one short finger 1; the three parts are distributed on the palm seat in an equilateral triangle; the structure of the short finger 1 is shown in fig. 2, the short finger 1 comprises three knuckle (a finger support 1-1 fixed on a palm seat, a middle knuckle 1-3 positioned in the middle and a fingertip 1-4 positioned at the outermost end) which are hinged in sequence; the short finger 1 is provided with 2 rotating joints, the rotating joints are connected through a pin shaft 1-2, and a pulley 1-7 is arranged on the pin shaft 1-2; each knuckle is provided with a support pillar; the finger body driving mechanism comprises shape memory alloy wires 1-6, a recovery rope 1-5, an electrifying device for electrifying the shape memory alloy wires 1-6 to contract and a recovery driving device for pulling the recovery rope 1-5; the outer ends of the restoring ropes 1 to 5 are fixed on the supporting columns of the fingertips 1 to 4, the inner ends of the restoring ropes are connected to the restoring driving devices, and the middle parts of the restoring ropes are in contact with the supporting columns of all the knuckles; the outer ends of the shape memory alloy wires 1-6 are fixed on the supporting columns of the outermost knuckles of the finger body, the other ends of the shape memory alloy wires are connected with the electrifying device, and the middle parts of the shape memory alloy wires sequentially pass around the supporting columns and the pulleys 1-7. The paw is driven by shape memory alloy wires 1-6 to grab and a rope 1-5 to restore to a straight shape, as shown in figures 8 and 9. The shape memory alloy wires 1-6 contract under the electrified state to generate a tensile force F. Due to the existence of the pulleys 1-7, the contraction of the metal wire has an angle, so that F can be divided into F1 in the horizontal direction and F2 in the vertical direction, and F1 can be ignored because each joint adopts a shell structure which is close to each other above a bent part. Meanwhile, the rotation limit position between two adjacent knuckles is that the two form an included angle of 90 degrees, and the shape memory alloy wires 1-6 are electrified to generate bending motion under the action of F2, so as to realize the grabbing action; when resetting, the shape memory alloy wires 1-6 are loosened after power failure, and the whole finger body can be restored to be straight by pulling the restoring rope 1-5.

In this embodiment, the structure of the long finger 2 is as shown in fig. 3, the long finger 2 includes four knuckles (a finger support fixed on the palm seat, two middle knuckles (2-3, 2-4) located in the middle, and a fingertip 2-5 located at the outermost end) hinged in sequence; the long finger 2 is provided with 3 rotating joints, the rotating joints are connected through a pin shaft 2-2, and a pulley 2-8 is arranged on the pin shaft 2-2; each knuckle is provided with a support pillar; the finger body driving mechanism comprises shape memory alloy wires 2-7, a recovery rope 2-6, an electrifying device for electrifying the shape memory alloy wires 2-7 to contract and a recovery driving device for pulling the recovery rope 2-6; the outer ends of the restoring ropes 2 to 6 are fixed on supporting columns of fingertips, the inner ends of the restoring ropes are connected to the restoring driving device, and the middle parts of the restoring ropes are in contact with the supporting columns of all the knuckles; the outer ends of the shape memory alloy wires 2-7 are fixed on the supporting columns of the outermost knuckles of the finger body, the other ends of the shape memory alloy wires are connected with the electrifying device, and the middle parts of the shape memory alloy wires sequentially pass around the supporting columns and the pulleys 2-8. The driving principle of the long finger 2 is the same as that of the short finger 1, and the description is omitted here.

In this embodiment, the palm seat includes a palm seat upper cover 3 and a palm seat lower cover 4; as shown in fig. 4, the inner wall of the top surface of the palm seat upper cover 3 is provided with a reciprocating circuitous guide groove 3-1, and the shape memory alloy wire is connected to the energizing device through the guide groove 3-1. Because the shape memory alloy wire is wholly flexible, has the short characteristics of stroke. Therefore, in order to increase the expansion amount and the stroke distance, the guide groove 3-1 with a reciprocating circuitous structure is arranged, the length of the shape memory alloy wire can be increased, and the corner of the guide groove 3-1 adopts fillet transition to avoid the obstruction of the groove wall to the shape memory alloy wire.

In this embodiment, as shown in fig. 5 and 6, a supporting plate is fixed on the inner wall of the top surface of the palm seat upper cover 3, and an electromagnet device is fixed on the supporting plate, and the electromagnet device includes a magnet box base 6-1, an electromagnet, an iron sheet, and a magnet box cover 6-2 fixed on the magnet box base 6-1; the inner end of the recovery rope is fixed on the iron sheet; the magnet box base 6-1 is provided with a chute 6-1-2 for guiding the iron sheet to slide and a magnet mounting position 6-1-3 for fixedly mounting the electromagnet, the end part of the chute 6-1-2 is provided with a rope outlet 6-1-1, and when the electromagnet is electrified, the electromagnet attracts the iron sheet to slide towards the iron sheet, so that the rope is tensioned and recovered. The supporting plate is provided with a plurality of columns (5-2, 5-3) for fixing the shape memory alloy wires or guiding the ropes to change directions and an outlet 5-1 for the shape memory alloy wires to pass through.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and those skilled in the art can make various modifications and variations; any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. The adaptive hand driven by the SMA and the rope in a composite mode is characterized by comprising a palm seat, a plurality of finger bodies arranged on the palm seat and a finger body driving mechanism used for driving the finger bodies to fold and reset; the finger body comprises a plurality of finger joints which are sequentially hinged, a support column which is fixedly arranged on each finger joint and a pulley which is arranged at a hinge shaft between two adjacent finger joints; the finger body driving mechanism comprises a shape memory alloy wire, a recovery rope, a power-on device for powering on the shape memory alloy wire to contract the shape memory alloy wire, and a recovery driving device for pulling the recovery rope; the outer end of the recovery rope is fixed on the support columns of the outermost knuckles of the finger body, the inner end of the recovery rope is connected to the recovery driving device, and the middle part of the recovery rope is in contact with the support columns of all knuckles; the outer end of the shape memory alloy wire is fixed on the supporting columns of the outermost knuckles of the finger body, the other end of the shape memory alloy wire is connected to the electrifying device, and the middle part of the shape memory alloy wire sequentially bypasses the supporting columns and the pulleys.

2. The SMA and rope composite driven adaptive hand of claim 1, wherein: the palm seat is internally provided with a reciprocating circuitous guide groove, and the shape memory alloy wire is connected with the electrifying device through the guide groove.

3. The SMA and rope composite driven adaptive hand of claim 2, wherein: the recovery driving device is an electromagnet device arranged in the palm seat; the electromagnet device comprises a magnet box base fixed in the palm base, an electromagnet, an iron sheet and a magnet box cover fixed on the magnet box base; the inner end of the recovery rope is fixed on the iron sheet; the magnet box base is provided with a sliding groove for guiding the sliding of the iron sheet and a magnet mounting position for fixedly mounting the electromagnet.

4. The SMA and rope composite driven adaptive hand of claim 3, wherein: the finger bodies are provided with three fingers which are respectively two long fingers and one short finger; the long finger comprises four knuckles; the short finger comprises three knuckles.

5. The SMA and rope composite driven adaptive hand of claim 4, wherein: a plurality of columns used for fixing shape memory alloy wires or guiding the rope to change direction are arranged in the finger seat.