CN110587589A

CN110587589A - Bending unit body and snake-shaped soft robot based on SMA drive

Info

Publication number: CN110587589A
Application number: CN201910760272.4A
Authority: CN
Inventors: 唐术锋; 梁威; 吕德稳; 周朋飞
Original assignee: Inner Mongolia University of Technology
Current assignee: Inner Mongolia University of Technology
Priority date: 2019-08-16
Filing date: 2019-08-16
Publication date: 2019-12-20
Anticipated expiration: 2039-08-16
Also published as: CN110587589B

Abstract

The invention discloses a bending unit body based on SMA drive and a snake-shaped flexible robot, and relates to the technical field of flexible robots, wherein the bending unit body comprises an internal supporting assembly and a plurality of SMA springs, the internal supporting assembly comprises a supporting piece, two spherical hinge devices and two joint end covers, each joint end cover comprises an end plate and a connecting shaft, one end of each connecting shaft is connected with the corresponding end plate, and the other end of each connecting shaft is connected with the corresponding supporting piece through the corresponding spherical hinge device; a plurality of spring steel plates are arranged at two ends of the supporting piece, and the other ends of the spring steel plates are in contact with the end plates; the two ends of the SMA spring are respectively connected with the two end plates. The snake-shaped soft robot is characterized in that a plurality of bending unit bodies are sequentially connected to form a straight line and comprise modularized torsion unit bodies. The bending unit body and the twisting unit body are arranged in a modularized mode, the structure is simple, the manufacture is convenient, the snake-shaped robot, the bionic trunk and the like can be assembled, the robots with different functions are assembled, and the bending unit body and the twisting unit body have great use value and popularization significance in production and life.

Description

Bending unit body and snake-shaped soft robot based on SMA drive

Technical Field

The invention relates to the technical field of soft robots, in particular to a bending unit body and a snake-shaped soft robot based on SMA drive.

Background

The robot refers to a man-made machine device capable of automatically executing tasks, and various functions are realized by the power and control capacity of the robot so as to replace or assist human work. The traditional robot is usually made of metal and other hard materials, is loaded and connected with electronic instruments and elements, and can be suitable for various use requirements such as industrial manufacturing, heavy object transportation and the like. However, in some unstructured environments and in small spaces, conventional robots cannot enter the unstructured environments at all and cannot assist human work.

In addition, a plurality of kinematic pairs are usually arranged on a body of the conventional robot, and different kinematic joints are formed through different kinematic combinations, so that the robot can complete different motion processes. The kinematic pairs mainly comprise revolute pairs and moving pairs, are usually driven by motors or hydraulic elements, have simple basic motions, and need to synthesize various basic motions when complex motion processes need to be executed, which usually needs to design extremely complex transmission mechanisms and control systems, and have the disadvantages of difficult design, complex structure, more parts, large occupied space, high failure rate, and tedious failure processing.

In order to adapt to various unstructured environments and narrow spaces and meet the use requirements of complex motions, those skilled in the art are engaged in developing and manufacturing a novel flexible robot, i.e., a soft robot. The body of the soft robot is made of soft materials, generally the Young modulus is lower than that of human muscles, the intelligent materials such as a Dielectric Elastomer (DE), an ionic polymer metal composite material (IPMC), a Shape Memory Alloy (SMA), a Shape Memory Polymer (SMP) and the like are generally selected for driving, and the action of the soft robot is completed by utilizing the change response of physical quantities such as an electric field, pressure, a magnetic field, chemical reaction, light, temperature and the like. At present, as the requirement of human beings on the robot is higher and higher, the skilled person puts more energy into the design and development of the soft robot. The design of the traditional robot, such as earthquake relief, bionic trunk mechanical arm and dynamic decoration robot, still has more challenges, and has become an important research and development subject for those skilled in the art.

Disclosure of Invention

The invention aims to provide a bending unit body based on SMA drive and a snake-shaped soft robot, wherein the snake-shaped soft robot can realize crawling through the bending control of each unit body; the function of the bionic trunk mechanical arm can be realized by fixing one end of the bionic trunk mechanical arm; various dynamic decoration robots can be manufactured by matching and combining a plurality of snake-shaped robots. The bending unit body is in a modularized design, can be conveniently and quickly assembled into the snake-shaped soft robot, the bionic trunk robot and the dynamic decoration robot, is simple in structure and convenient to manufacture, and provides a new idea for the design and manufacture of the soft robot.

The purpose of the invention is realized by the following technical scheme:

the bending unit body based on the SMA drive comprises an internal support component and a plurality of SMA springs;

the internal support assembly comprises a support piece, two spherical hinge devices, two joint end covers and a plurality of spring steel sheets, wherein the two joint end covers are respectively arranged at two ends of the support piece;

the joint end cover comprises end plates and a connecting shaft, the two end plates are arranged oppositely, one end of the connecting shaft is connected with the center of each end plate, and the other end of the connecting shaft is connected with one end of the supporting piece through the spherical hinge device;

a plurality of spring steel plates are fixedly arranged at both ends of the supporting piece, the spring steel plates are uniformly distributed by taking the axis of the connecting shaft as the center, and one end of each spring steel plate, which is far away from the supporting piece, is in contact with the end plate;

the two ends of the SMA springs are fixedly connected with the two end plates respectively, and the SMA springs are uniformly distributed by taking the centers of the end plates as circle centers.

Furthermore, the spherical hinge device comprises a ball seat and a ball head, the ball head is rotatably arranged in the ball seat, a through hole is processed on the ball head, and the connecting shaft is slidably arranged in the through hole; notches are formed in the two ends of the supporting piece, and the notches are matched with one end of the connecting shaft.

Further, the ball seat is cylindrical split type structure, run through on the ball seat and be provided with through-hole a, the side of through-hole a be with the sphere of bulb looks adaptation, the notch just is to the one end setting of ball seat.

Furthermore, the spring steel plate is bent, one end of the spring steel plate is fixedly connected with one end of the supporting piece through a bolt, and the distance between one end of the spring steel plate close to the supporting piece and the connecting shaft at the end is larger than that between the other end of the spring steel plate and the connecting shaft.

Further, still include the rubber overcoat, the rubber overcoat includes a plurality of telescopic flexible sleeve pipes, the flexible sleeve pipe both ends respectively with two end plate fixed connection, it is a plurality of the SMA spring is worn to locate a plurality of respectively in the flexible sleeve pipe.

Furthermore, the flexible sleeve is a spiral telescopic pipe.

The snake-shaped soft robot based on the SMA drive comprises a plurality of bending unit bodies based on the SMA drive, and the bending unit bodies are sequentially connected to form a straight line.

Furthermore, the snake-shaped soft robot based on SMA drive also comprises a plurality of torsion unit bodies, wherein each torsion unit body comprises a rigid spring, two joint end covers and a plurality of SMA springs, the two joint end covers are oppositely arranged, two ends of the rigid spring are respectively connected with the centers of the two joint end covers, and two ends of the SMA springs are respectively fixedly connected with the two joint end covers;

the SMA springs and the rigid springs are arranged in a staggered mode, connection points a of the SMA springs and one of the joint end covers are uniformly distributed around the center of the joint end cover, connection points b of the SMA springs and the other joint end cover are uniformly distributed around the center of the joint end cover, and included angles between the center lines of the SMA springs and the two joint end covers are equal;

the torsion unit body is used for replacing any one or more bending unit bodies.

Furthermore, the torsion unit body further comprises a telescopic rod, the rigid spring sleeves the telescopic rod, and two ends of the telescopic rod are respectively connected with the two joint end covers in a rotatable mode.

The invention has the beneficial effects that:

the bending unit body based on SMA drive can realize bending at any angle, has simple structure, smooth bending action without blocking, is in modular design, can be directly assembled into a snake-shaped robot, and provides a new idea for the design of a soft robot. When the SMA spring is installed, a supporting force can be provided to keep the SMA spring in a stretched state, so that the SMA spring is prevented from contacting with foreign objects to a certain extent, and a protection effect is achieved; the spiral extension tube is arranged to further protect the SMA spring, so that heat dissipation of the SMA spring in power failure is not hindered, and the lag time of the SMA spring is reduced.

The snake-shaped soft robot based on SMA drive can be formed by directly connecting the bending unit bodies with the modular structure, can simulate the movement of a snake by controlling the bending action of each unit body, realizes the creeping advance, and can be applied to various unstructured use environments. The modularized torsion unit body is arranged, any one or more bending unit bodies can be replaced to form the bionic trunk, various movements such as bending, torsion and linear movement are achieved, the bionic trunk can be applied to various aspects of production and life through combination, and the use value and the popularization significance are high.

Drawings

FIG. 1 is a schematic structural diagram of a bending unit body based on SMA drive according to the present invention;

FIG. 2 is a schematic structural diagram of an internal support assembly in an SMA drive-based bending unit body according to the present invention;

FIG. 3 is a schematic structural diagram of a hinge device in a bending unit body based on SMA drive;

FIG. 4 is a schematic structural diagram of the snake-shaped soft robot based on SMA drive, which is composed of bending unit bodies in whole;

fig. 5 is a schematic structural view of the torsion unit body.

Detailed Description

The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.

As shown in fig. 1 to 3, the SMA drive based bending unit body includes an inner support assembly 100 and a number of SMA springs 200. The internal support assembly 100 includes a support member 110, two ball-and-socket joints 150, two articulating end caps, and a plurality of spring steel plates 140.

The two joint end caps are respectively arranged at two ends of the supporting member 110, each joint end cap comprises an end plate 120 and a connecting shaft 130, the two end plates 120 are oppositely arranged, one end of the connecting shaft 130 is connected with the center of the end plate 120, the other end of the connecting shaft 130 is connected with one end of the supporting member 110 through a spherical hinge device 150, and under the action of the spherical hinge device 150, the connecting shaft 130 can deflect in all directions in a certain range relative to the supporting member 110. The two ends of the supporting member 110 are both fixedly provided with a plurality of spring steel plates 140, the plurality of spring steel plates 140 are uniformly distributed around the axis of the connecting shaft 130, and one end of the spring steel plate 140 away from the supporting member 110 is in contact with the end plate 120. During the deflection of the connecting shaft 130, the side surface of the end plate 120 is in contact with at least one end of one spring steel plate 140, the spring steel plate 140 is compressed to store elastic potential energy and realize buffering during the deflection action, and after the deflection action is finished, the compressed spring steel plate 140 releases the elastic potential energy to reset the spring steel plate. In implementation, one end of the spring steel plate 140 is fixedly connected with the support member 110 through a bolt, so that the spring steel plate can be conveniently disassembled, assembled and replaced; the spring steel plate 140 is bent, and a distance between one end of the spring steel plate 140 close to the supporting member 110 and the connecting shaft 130 is greater than a distance between the other end of the spring steel plate 140 and the connecting shaft 130, so as to ensure that a reaction force applied when the end plate 120 compresses the spring steel plate 140 is more balanced and controllable during a bending motion.

The two ends of the SMA springs 200 are respectively fixedly connected with the two end plates 120, the SMA springs 200 are uniformly distributed by taking the center of the end plate 120 as the center of a circle, and when a certain SMA spring 200 is electrically contracted, the positions where the two end plates 120 are connected with the SMA spring 200 are pulled to be close to each other, so that the bending unit body realizes the bending function.

As shown in fig. 1, six SMA springs 200 are uniformly arranged in the present embodiment, which can realize 12 bending actions in different directions, and different numbers of SMA springs 200 can be arranged to meet different requirements in specific implementation. In practice, since one end of the spring steel plate 140 is in contact with the end plate 120, the SAM spring 200 can maintain a slight tension after installation, so that the SAM spring 200 is in a stretched state, and the SMA spring 200 can be prevented from contacting with a foreign object to a certain extent during movement, thereby protecting the same. When implementing, still be provided with rubber overcoat 300, rubber overcoat 300 includes a plurality of telescopic flexible sleeve pipes, the flexible sleeve pipe both ends respectively with two end plate 120 fixed connection, in a plurality of flexible sleeve pipes are worn to locate respectively to a plurality of SMA springs 200 carry out abundant protection. During specific implementation, this flexible sleeve chooses for use spiral flexible pipe, as shown in fig. 1 in this embodiment, this spiral flexible pipe comprises three heliciform cables, and these three heliciform cables set up coaxially, and it wholly is three helical structure, and in the use, there is the pulling force to two end plates 120 itself, and the pipe shaft is the fretwork state, and this when protection SMA spring 200 does not contact with the foreign object, still can not hinder SMA spring 200's when cutting off the power supply heat dissipation, reduces SMA spring 200's dead time itself.

Further, the ball joint device 150 includes a ball seat 151 and a ball head 152, the ball head 152 is rotatably disposed in the ball seat 151, a through hole 153 is formed in the ball head 152, and the connecting shaft 130 is slidably disposed in the through hole 153; both ends of the supporting member 110 are provided with notches 160, and the notches 160 are fitted with one end of the connecting shaft 130. When the ball seat is implemented, the ball seat 151 is a cylindrical split structure, a through hole a is formed in the ball seat 151 in a penetrating mode, and the side face of the through hole a is a spherical surface matched with the ball head 152. The arrangement enables the end part of the connecting shaft 130 to slide in the ball head 152, and the notch 160 is arranged to give enough sliding space to the end part, so that the motion synthesis of the bending unit body is further increased during application, the bending motion track is not a simple circular arc, but a curve formed by the synthesis of the bending motion and the axial motion, and the actual bending motion of snake-shaped wriggling is more met; meanwhile, when one SMA spring 200 is contracted by power supply, the connecting shaft 130 allows axial sliding, so that the SMA springs 200 on the opposite side of the SMA spring 200 are relatively less stretched, and the bending action is smoother.

The snake-shaped soft robot based on SMA drive can be formed by sequentially connecting a plurality of bending unit bodies based on SMA drive and assembling the bending unit bodies in a straight line shape, the structure of the snake-shaped soft robot is shown in figure 4, each SMA spring 200 of each bending unit body is subjected to power-on and power-off control, the movement of a snake can be simulated, and the snake-shaped soft robot can creep and advance through bending movement.

Furthermore, the snake-shaped soft robot also comprises a plurality of torsion unit bodies. The structure of the torsion unit body is shown in fig. 5, and the torsion unit body comprises a rigid spring 310, two joint end covers and a plurality of SMA springs 200, wherein the two joint end covers are oppositely arranged, two ends of the rigid spring 310 are respectively connected with the centers of the two joint end covers, and two ends of the SMA springs 200 are respectively fixedly connected with the two joint end covers; the SMA springs 200 and the rigid springs 310 are arranged in a staggered mode, the connection point a of one of the SMA springs 200 and one of the joint end covers is uniformly distributed around the center of the joint end cover, the connection point b of the other joint end cover and the SMA springs 200 are uniformly distributed around the center of the joint end cover, and included angles between the center lines of the SMA springs 200 and the two joint end covers are equal. Electrifying a plurality of SMA springs 200 of the torsion unit body at the same time to enable the SMA springs to contract, and pulling two joint end covers to move mutually in the process, so that a rigid spring 310 in the middle is compressed and potential energy is accumulated; on the other hand, because each SMA spring 200 and the stiff spring 310 are arranged in a staggered manner and have the same angle, they can drive the two joint end caps to rotate relatively within a certain angle range when stretched and contracted simultaneously, thereby realizing the function of torsional motion. Based on the characteristics of the SMA spring, the torsion angle can be controlled within a certain range according to the electrifying condition. When each SMA spring 200 is de-energized, the potential energy of the stiff spring 310 is released and the torsion unit body can complete the return. In specific implementation, the torsion unit body is in a spatially symmetrical structure as a whole, that is, the diameter of a circle formed by connecting the connecting points a is the same as that of a circle formed by connecting the connecting points b, the stress of the SMA spring 200 is balanced, the whole torsion unit body works more stably, and the control of the torsion angle is more accurate. In the torsion unit body, the connecting shaft 130 of the joint end cover is rotatably connected with the end plate 120, so that the situation that the rigid spring 310 is subjected to torque can be effectively avoided, and the operation of the rigid spring is more reliable. Further, the torsion unit body further comprises a telescopic rod 320, the rigid spring 310 is sleeved on the telescopic rod 320, and two ends of the telescopic rod 320 are rotatably connected with the two joint end covers respectively. The telescopic rod 320 is arranged to effectively limit the rigid spring 310 and only allow the rigid spring 310 to stretch along the axial direction, so that the stability of the torsional movement of the torsional unit body is ensured, and the situation that the SMA springs 200 in the torsional unit body are mutually wound in the torsional process is prevented.

When the snake-shaped soft robot is applied to the snake-shaped soft robot, the torsion unit body can replace any one or more bending unit bodies, so that the snake-shaped robot can bend, twist and axially move in a certain range, and when one end of the snake-shaped soft robot is fixed, the bionic trunk function can be realized by controlling the movement of each unit body. Specifically, the bending motion can be directly synthesized by the motion process of the bending unit bodies, the twisting motion can be directly synthesized by the motion process of the twisting unit bodies added in the bending motion, and if only axial linear motion needs to be executed, the twisting unit bodies need to be used in pairs, so that the directions of the twisting unit bodies are opposite and the twisting unit bodies are twisted simultaneously. The snakelike soft robot can expand multiple functions to form different robots, for example, a bracket is arranged, one ends of three snakelike soft robots are fixed on the bracket, and the snakelike soft robots can be directly assembled into a manipulator with a grabbing function; for example, a breathing lamp is added between each unit body, a plurality of soft robots are installed in any mode, the dynamic decoration robot can be assembled, various shapes are shown for people to watch, and the dynamic decoration robot has high popularization value in various aspects such as production, life and the like.

The foregoing is illustrative of the preferred embodiments of this invention, and it is to be understood that the invention is not limited to the precise form disclosed herein and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the concept as disclosed herein, either as described above or as apparent to those skilled in the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The bending unit body based on SMA drive is characterized by comprising an internal support assembly (100) and a plurality of SMA springs (200);

the internal support assembly (100) comprises a support piece (110), two spherical hinge devices (150), two joint end covers and a plurality of spring steel sheets (140), wherein the two joint end covers are respectively arranged at two ends of the support piece (110);

the joint end cover comprises end plates (120) and a connecting shaft (130), the two end plates (120) are arranged oppositely, one end of the connecting shaft (130) is connected with the center of the end plates (120), and the other end of the connecting shaft (130) is connected with one end of the supporting piece (110) through the spherical hinge device (150);

a plurality of spring steel plates (140) are fixedly arranged at two ends of the supporting piece (110), the spring steel plates (140) are uniformly distributed by taking the axis of the connecting shaft (130) as the center, and one end, far away from the supporting piece (110), of each spring steel plate (140) is in contact with the end plate (120);

the two ends of the SMA springs (200) are fixedly connected with the end plates (120) respectively, and the SMA springs (200) are uniformly distributed with the centers of the end plates (120) as the circle center.

2. The SMA drive-based curving unit body of claim 1, wherein the spherical hinge device (150) comprises a ball seat (151) and a ball head (152), the ball head (152) is rotatably arranged in the ball seat (151), a through hole (153) is processed on the ball head (152), and the connecting shaft (130) is slidably arranged in the through hole (153); both ends of the supporting piece (110) are provided with notches (160), and the notches (160) are matched with one end of the connecting shaft (130).

3. The SMA drive-based bending unit body according to claim 2, wherein the ball seat (151) is a cylindrical split structure, a through hole a is formed in the ball seat (151) in a penetrating manner, the side surface of the through hole a is a spherical surface matched with the ball head (152), and the notch (160) is arranged opposite to one end of the ball seat (151).

4. The SMA drive-based bending unit body according to claim 1, wherein the spring steel plate (140) is bent, one end of the spring steel plate (140) is fixedly connected with one end of the support member (110) through a bolt, and the distance between one end of the spring steel plate (140) close to the support member (110) and the connecting shaft (130) of the end is greater than the distance between the other end of the spring steel plate and the connecting shaft (130).

5. The internal supporting component of a bending unit body as claimed in claim 1, further comprising a rubber casing (300), wherein the rubber casing (300) comprises a plurality of flexible telescopic pipes, two ends of each flexible telescopic pipe are respectively fixedly connected with the two end plates (120), and a plurality of SMA springs (200) are respectively arranged in the flexible telescopic pipes in a penetrating manner.

6. The SMA drive-based bending unit body of claim 5, wherein the flexible sleeve is a helical bellows.

7. A snake-shaped soft robot based on SMA drive, which is characterized by comprising a plurality of the bending unit bodies based on SMA drive according to claim 1, wherein the bending unit bodies are sequentially connected to form a straight line.

8. The snake-shaped soft robot based on SMA drive of claim 7, further comprising a plurality of torsion unit bodies, wherein each torsion unit body comprises a rigid spring (310), two joint end covers and a plurality of SMA springs (200), the two joint end covers are arranged oppositely, two ends of the rigid spring (310) are respectively connected with the centers of the two joint end covers, and two ends of the SMA springs (200) are respectively fixedly connected with the two joint end covers;

the SMA springs (200) and the rigid springs (310) are arranged in a staggered mode, a connecting point a of one of the SMA springs (200) and one of the joint end covers is uniformly distributed around the center of the joint end cover, a connecting point b of the other joint end cover is uniformly distributed around the center of the joint end cover, and included angles between the center lines of the SMA springs (200) and the two joint end covers are equal;

9. The snake-shaped soft robot based on SMA drive of claim 8, wherein the torsion unit body further comprises a telescopic rod (320), the rigid spring (310) is sleeved on the telescopic rod (320), and two ends of the telescopic rod (320) are respectively rotatably connected with the two joint end covers.