CN114589685A - Shape memory alloy wire-driven soft robot based on mother-child origami - Google Patents

Abstract

The invention discloses a shape memory alloy wire-driven soft robot based on child and mother origami, which comprises a child and mother origami main body and two SMA wires, wherein the child and mother origami main body is composed of two sub-structures and two mother structures. The child structure and the parent structure are both origami tube structures, and the origami tube structure is a tubular structure composed of two identical Miura origami basic units, and the origami tube structure is about the middle symmetry plane formed by the four middle crease lines. Symmetrical, the nozzles on both sides are diamond-shaped; the sub-structure is the same as the parent structure, and the size of the sub-structure is smaller than that of the parent structure. Two SMA wires are respectively located on the upper and lower surfaces of the main body of the child and mother origami, and are constrained to form a U shape. The two SMA wires of the present invention can make the robot move forward in one direction under alternating current. The mother-child origami has remarkable bending and torsion resistance, which ensures the stability of the robot's standing and provides an anisotropic friction mechanism that facilitates movement.

Description

Shape memory alloy wire-driven soft robot based on mother-child origami

technical field

The invention belongs to the field of soft robot design, in particular to a shape memory alloy wire-driven soft robot based on child-mother origami.

Background technique

Rigid robots are not suitable for storage, transportation or work in small spaces due to their bulky and rigid frames. Therefore, how to design lightweight and flexible soft robots has become one of the important research topics in the scientific and engineering fields.

In recent decades, researchers have proposed a new structure called origami. The term origami is used to describe an ancient art of folding, with the root ori meaning folding and -gami meaning paper. The basic theory of origami is to deform a sheet of paper from two dimensions into a three-dimensional geometric mosaic, and in recent decades this idea has been studied and applied beyond purely aesthetic purposes. In a rigid origami pattern, the surface enclosed by the crease line is not allowed to stretch or bend during the folding process. The rigid folding, planar folding, and unfoldable properties make rigid origami structures a wide range of potential applications. As a basic rigid origami pattern, Miura origami possesses geometric simplicity and excellent mechanical properties, and can be uniquely described from a kinematic perspective. Its motion, this novel structure has caught the attention of researchers, and many different aspects of this structure have been studied.

Due to the foldability and special mechanical properties of the origami structure, it can be used as a good carrier for lightweight and compliant actuation materials such as shape memory alloy wires to form soft robots with mobility.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of the prior art, the present invention provides a shape memory alloy wire-driven soft robot based on child-mother origami.

The invention provides a shape memory alloy wire-driven soft robot based on child-mother origami, which is characterized by comprising a child-mother origami main body and two shape memory alloy wires. The child-mother origami main body consists of two substructures, two mother Structure and composition. Both the sub-structure and the parent structure are origami tube structures, and the origami tube structure is a tubular structure composed of two identical Miura origami basic units, and the origami tube structure is about the middle symmetry plane formed by the four middle crease lines. Symmetrical, the nozzles on both sides are diamond-shaped; the substructure is the same as the parent structure, and the size of the substructure is 0.5-0.7 times the size of the parent structure;

The shape memory alloy wire-driven soft robot based on child-mother origami is produced by the following method:

1) The two female structures are arranged in the same posture, and the respective middle symmetrical planes of the two female structures and the pipe wall surfaces on the front and rear sides are in a vertical state; The walls are in contact with each other, and the median plane of symmetry is coplanar;

2) Turn one of the female structures upside down, so that the complementary pipe wall surfaces are in contact and the middle symmetry planes are coplanar; adjust the height of one of the female structures so that the lower right corner of the nozzles on both sides of one female structure is connected to the pipes on both sides of the other female structure. The upper left corner of the mouth is attached, and in this state, the two mother structures are pasted to make them fixed to each other;

3) Fix a sub-structure directly under the two parent structures with the same attitude as the parent structure, and make the two complementary tube wall surfaces of the two sub-structures fit together; the middle symmetry plane of the four origami tube structures is located vertically flat and coplanar;

4) With the two sub-structures at the bottom, make the three vertices of the two sub-structures contact the support surface, place the origami main body, and set the orientation as positive; paste a piece of silicone foam on the three tips of the lower surfaces of the two parent structures, respectively, Make a shape memory alloy wire pass through the three silicone foams on the lower surface and form a U shape; paste a piece of silicone foam on the mountain line and two tips of the upper surface of the two mother structures respectively, and make a shape memory alloy wire pass through. Pass the three silicone foams on the top surface and make a W shape.

As a preferred solution of the present invention, the size of the substructure is 0.6 times the size of the parent structure.

As a preferred solution of the present invention, silica gel foam is arranged between the shape memory alloy wire and the fixing point of the origami body, and the silica gel foam is fixed on the fixing point of the origami body. The shape memory alloy wire is fixed through the silica gel foam.

As a preferred solution of the present invention, the length of the shape memory alloy wire on the lower surface of the mother structure should be such that after passing through all the silicone foam on the lower surface, the head and tail ends can touch the ground when the origami body is placed on a horizontal plane.

As a preferred solution of the present invention, the length of the shape memory alloy wire on the upper surface of the mother structure should be sufficient to wrap around the wire for connecting the power supply after passing through all the silicone foam on the upper surface.

As a preferred solution of the present invention, two shape memory alloy wires are connected to an external power supply, and the two shape memory alloy wires receive electrical signals alternately.

As a preferred solution of the present invention, the two shape memory alloy wires are linear in an unconstrained and electrified state.

As a preferred solution of the present invention, the U-shaped structure or the W-shaped structure of the shape memory alloy wire is symmetrical with respect to the median symmetry plane of the origami main body.

As a preferred solution of the present invention, the shape memory alloy wire is a 0.5 mm single-pass shape memory alloy wire, preferably an SMA wire.

Compared with the prior art, the robot of the present invention is composed of two pairs of Miura origami tubes with different sizes, and has significant bending and torsion resistance, so that only obvious deformation can occur in the folding direction, so it has It is beneficial to accept the drive of the shape memory alloy wire to produce directional deformation. And the special U-shape arrangement of the shape memory alloy wire in the present invention can effectively convert the force generated by the shape memory alloy wire into the force for folding the origami structure, thereby completing the driving of the whole origami structure. The special support method of the mother-child origami structure also ensures the stability of the robot's standing and provides an anisotropic friction mechanism that facilitates movement.

Description of drawings

Fig. 1 is the structural schematic diagram of the main body of the mother-child origami of the present invention (side view);

2 is a schematic structural diagram of a shape memory alloy wire-driven soft robot based on child-mother origami of the present invention;

3 is a schematic diagram of the bottom structure of a shape memory alloy wire-driven soft robot based on child-mother origami of the present invention;

4 is a schematic diagram of a compressed state of a shape memory alloy wire-driven soft robot based on child-mother origami according to the present invention;

FIG. 5 is a schematic diagram of the fabrication of the child and parent structures of the present invention.

In the figure, the mother structure 1, the substructure 2, the silicone foam 3, the top SMA wire 4, and the bottom SMA wire 5.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relationship between various components under a certain posture (as shown in the accompanying drawings). The relative positional relationship, the movement situation, etc., if the specific posture changes, the directional indication also changes accordingly.

As shown in Figures 1-5, this embodiment provides a shape memory alloy wire-driven soft robot based on child-mother origami, which includes a child-mother origami main body and two SMA wires. As shown in Figure 1, the child-mother origami The origami main body is composed of two substructures 2 and two parent structures 1 . The substructure 2 and the parent structure 1 are both origami tube structures, and the origami tube structure is a tubular structure composed of two identical Miura origami basic units (as shown in Figure 5), and the origami tube structure is folded about the middle four. The middle plane of symmetry formed by the traces is left-right symmetrical, and the nozzles on both sides are rhombus-shaped; the substructure is the same as the parent structure, and the size of the substructure is 0.6 times that of the parent structure.

As shown in Figure 5, the child and parent structures can be made by the following methods: 1) Use a laser engraving machine to engrave the folded folds of the planned and designed four Miura basic units that form the child structure and the four Miura basic units that form the parent structure. The crease line, the crease diagram of which is shown in Figure 5(a), in which the size of the Miura basic unit that composes the substructure is 0.6 times that of the Miura basic unit of the parent structure; 2) Fold the crease to make the Miura basic unit from the two-dimensional The structure is changed to a three-dimensional structure; 3) Two identical Miura basic units are mirror-joined into a tubular structure with the edges folded inward for easy connection.

As shown in Figures 1-5, in an optional embodiment, the shape memory alloy wire-driven soft robot based on child-mother origami is manufactured by the following method:

1) The two female structures are arranged in the same posture, and the respective middle symmetrical planes of the two female structures and the pipe wall surfaces on the front and rear sides are in a vertical state; The walls are in contact with each other, and the median plane of symmetry is coplanar;

2) Turn one of the female structures upside down, so that the complementary pipe wall surfaces are in contact and the middle symmetry planes are coplanar; adjust the height of one of the female structures so that the lower right corner of the nozzles on both sides of one female structure is connected to the pipes on both sides of the other female structure. The upper left corner of the mouth is attached, and in this state, the two mother structures are pasted to make them fixed to each other;

3) Fix a sub-structure directly under the two parent structures with the same attitude as the parent structure, and make the two complementary tube wall surfaces of the two sub-structures fit together; the middle symmetry plane of the four origami tube structures is located vertically flat and coplanar;

4) The two sub-structures are at the bottom, so that the three vertices of the two sub-structures contact the supporting surface, place the origami main body, and set the orientation as positive (the special support method of the sub-mother origami structure also ensures the stability of the robot standing, and Provide anisotropic friction mechanism that facilitates movement); paste a piece of silicone foam 3 at the three tips of the lower surface of the two mother structures respectively, so that a bottom SMA wire 5 passes through the three silicone foams on the lower surface and presents U shape; paste a piece of silicone foam 3 on the mountain line and the two tips on the upper surface of the two mother structures, so that a top SMA wire 4 passes through the three silicone foams on the upper surface and forms a W shape.

The temperature-controlled shape memory alloy wire undergoes a phase transformation and deformation when heated, thereby generating a force on the restrained portion on it. As shown in Figures 2 and 3, the present invention has completed a flexible two-way actuator composed of shape memory alloy wires. Figure 4 is a schematic diagram of the compressed state of the shape memory alloy wire driven soft robot based on child-mother origami of the present invention. Under the heating of the periodic electrical signal generated by the programmable power supply, a pair of shape memory alloy wires generate corresponding heat signals respectively, so the origami structure has the periodic behavior of folding and unfolding, and it is not affected by the shape memory alloy wire. The force produces an undesired form of deformation. When the robot crawls, the change of the stiffness of the assembled shape memory alloy wire in contact with the ground can create an anisotropic friction mechanism, with the help of this friction mechanism, the robot will produce directional motion. The invention places the robot on a smooth and flat ground and applies electrical signals, and the robot crawls with periodic behavior.

In the present invention, two SMA wires are respectively connected with two power sources, and the head and tail ends of each SMA wire are connected with the positive and negative electrodes of the same power source. Turn on the power supply connected to the bottom SMA wire 5 on the lower surface of the mother structure, then the SMA wire will be energized and straightened. Due to the anisotropy of frictional force on the bottom surface of the origami structure, the head of the robot can move forward and the tail of the robot will not move; The top SMA wire 4 on the upper surface of the structure is connected to the power supply, then the SMA wire is energized and straightened. Due to the anisotropy of frictional force on the bottom surface of the origami structure, the tail of the robot can move forward while the head does not move, alternately and periodically make the bottom SMA wire Wire 5 and top SMA wire 4 are energized so that the robot can move forward.

As shown in Fig. 1, this embodiment shows an origami structure with simple structure but functional mechanical properties-child-mother origami, which has special mechanical properties such as strong bending resistance, torsion resistance and stable standing ability ; The mechanical properties of the mother-child origami can not only serve the robot, but also have a wider range of applications.

By rationally designing the origami structure, the present invention can simply guide a compliant actuator (such as a shape memory alloy wire) to generate a directional force on the structure to complete a specified driving behavior. Through experiments, the present invention has proved that this method can be applied to the design of the physical structure and the actuator of the soft robot, and realizes the soft robot with the ability to move autonomously. This achievement expands the structural design method of soft robots and provides a new idea for the design of origami-based soft robots.

Claims (9)

1. A shape memory alloy wire-driven soft robot based on child-mother origami, is characterized in that, comprises child-mother origami main body and two shape memory alloy wires, and described child-mother origami main body is made up of two substructures, two mother structures . Both the sub-structure and the parent structure are origami tube structures, and the origami tube structure is a tubular structure composed of two identical Miura origami basic units, and the origami tube structure is about the middle symmetry plane formed by the four middle crease lines. Symmetrical, the nozzles on both sides are diamond-shaped; the substructure is the same as the parent structure, and the size of the substructure is 0.5-0.7 times the size of the parent structure; The shape memory alloy wire-driven soft robot based on child-mother origami is produced by the following method: 1) The two female structures are arranged in the same posture, and the respective middle symmetrical planes of the two female structures and the pipe wall surfaces on the front and rear sides are in a vertical state; The walls are in contact with each other, and the median plane of symmetry is coplanar; 2) Turn one of the female structures upside down, so that the complementary pipe wall surfaces are in contact and the middle symmetry planes are coplanar; adjust the height of one of the female structures so that the lower right corner of the nozzles on both sides of one female structure is connected to the pipes on both sides of the other female structure. The upper left corner of the mouth is attached, and in this state, the two mother structures are pasted to make them fixed to each other; 3) Fix a sub-structure directly under the two parent structures with the same attitude as the parent structure, and make the two complementary tube wall surfaces of the two sub-structures fit together; the middle symmetry plane of the four origami tube structures is located vertically flat and coplanar; 4) With the two sub-structures at the bottom, make the three vertices of the two sub-structures contact the support surface, place the origami main body, and set the orientation as positive; paste a piece of silicone foam on the three tips of the lower surfaces of the two parent structures, respectively, Make a shape memory alloy wire pass through the three silicone foams on the lower surface and form a U shape; paste a piece of silicone foam on the mountain line and two tips of the upper surface of the two mother structures respectively, and make a shape memory alloy wire pass through. Pass the three silicone foams on the top surface and make a W shape. 2 . The shape memory alloy wire-driven soft robot based on child-parent origami according to claim 1 , wherein the size of the child structure is 0.6 times that of the parent structure. 3 . 3 . The shape memory alloy wire-driven soft robot based on child-mother origami according to claim 1 , wherein a silicone foam is arranged between the shape memory alloy wire and the fixing point of the origami body, and the silicone foam is fixed on the origami body. 4 . The shape memory alloy wire is fixed through the silicone foam on the fixing point. 4. The shape memory alloy wire-driven soft robot based on child-mother origami according to claim 3, characterized in that, the length of the shape memory alloy wire on the lower surface of the mother structure should be sufficient after passing through all the silicone foams on the lower surface, The head and tail ends can touch the ground when the origami body is placed on a horizontal surface. 5 . The shape memory alloy wire-driven soft robot based on child-mother origami according to claim 3 , wherein the length of the shape memory alloy wire on the upper surface of the mother structure should satisfy the length of the head and tail after passing through all the silicone foams on the upper surface. 6 . The margins at both ends are sufficient to wrap the wires used to connect the power supply. 6 . The shape memory alloy wire-driven soft robot based on child-mother origami according to claim 1 , wherein the two shape memory alloy wires are connected to an external power supply, and the two shape memory alloy wires receive electrical signals alternately. 7 . 7 . The shape memory alloy wire-driven soft robot based on child-mother origami according to claim 1 , wherein the two shape memory alloy wires are linear in an unconstrained and energized state. 8 . 8 . The shape memory alloy wire-driven soft robot based on parent-child origami according to claim 1 , wherein the U-shaped structure or the W-shaped structure of the shape memory alloy wire is symmetrical with respect to the median symmetry plane of the origami main body. 9 . 9 . The shape memory alloy wire-driven soft robot based on child-mother origami according to claim 1 , wherein the shape memory alloy wire is an SMA wire. 10 .

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