Multi-directional moving magnetic control soft robot based on magnetic field control and preparation and driving method of multi-directional moving magnetic control soft robot

Abstract

The invention relates to a multidirectional moving magnetic control soft robot based on magnetic field control and a preparation and driving method thereof, a magnetic unit in a central area of the robot is formed by embedding a cylindrical magnet into an Ecoflex-30 elastomer, and four magnetic units on the periphery are formed by mixing NdFeB magnetic powder and Ecoflex-30 and then curing; and a magnetic unit with a single horizontal magnetic moment direction is formed through horizontal magnetization. And the peripheral magnetic units are adhered to the side surfaces of the central area magnetic unit through Ecoflex-30 colloid to form flexible connection. The robot can move in the front, back, left and right directions through accurate control of an external magnetic field. The magnetic control soft robot provided by the invention has the advantages of simple structure, flexible movement capability and efficient driving mode.

Description

Technical Field

[0001] The present invention belongs to the technical field of soft robots, and particularly relates to a multi-directional moving magnetically controlled soft robot based on magnetic field control, and a preparation and driving method thereof. Background Art

[0002] As a new type of robot technology with flexibility and adaptability, soft robots show great potential in the fields of micro-operation, medical treatment, exploration, repair, etc. Compared with traditional rigid robots, soft robots can adapt to complex environments through their own flexible deformation and operate in narrow spaces, fragile objects or irregular surfaces. However, existing soft robots usually rely on pneumatic, electric or hydraulic drive systems, which are complex, bulky and require external energy supply, restricting their applications in miniaturization and lightweight. With the in-depth research of magnetic materials in soft robots, magnetically controlled soft robots based on magnetic field control have gradually become an important research direction. Magnetically controlled soft robots achieve motion control by regulating the magnetic response of materials through an external magnetic field, without the need for traditional drive systems, and have the characteristics of high reliability, simple structure and strong flexibility, especially suitable for application scenarios with high flexibility and adaptability requirements. In the medical field, the development of technologies such as minimally invasive surgery, targeted therapy and in vivo diagnosis has put forward higher requirements for the flexibility and safety of medical devices. Although traditional rigid robots (such as surgical robotic arms, endoscopes, etc.) have the advantages of precision and stability, their rigid structures are likely to cause tissue damage or patient discomfort in narrow human cavities (such as blood vessels, gastrointestinal tracts, bronchi). For example, in vascular intervention surgery, existing guide wires and catheters rely on manual operation, with insufficient multi-degree-of-freedom motion ability, difficult to flexibly turn in complex blood vessel branches, and there is a risk of blood vessel perforation; in gastrointestinal examinations, the rigid catheter of traditional endoscopes may cause mucosal abrasions and is difficult to reach long and narrow curved areas such as the small intestine; in targeted drug delivery, passive diffusion-based nano-drug delivery systems lack autonomous motion ability and are difficult to accurately locate lesions in dynamic blood flow or mucus; in postoperative repair, rigid stents are likely to cause inflammatory reactions or displacements and cannot dynamically conform to tissue damage sites.

[0003] Although the existing magnetically controlled soft robot technology provides potential solutions to the above problems, its design is mostly limited to simple linear motion and single-degree-of-freedom control. For example, under magnetic field regulation, the robot can achieve basic movement by rolling or one-way bending, but in a dynamic anatomical environment (such as tissue displacement caused by heartbeat and breathing), its motion accuracy and adaptability significantly decrease. In addition, complex magnetic field regulation systems (such as multi-axis coil collaborative control) increase the difficulty of clinical operation and limit practical applications. Specifically, it shows the following problems: insufficient degrees of freedom of motion, making it difficult to coordinate motion in multiple directions to adapt to complex terrains such as blood vessel bifurcations or intestinal folds; low driving efficiency, in viscous body fluids or dynamic physiological environments, simple magnetic driving strategies are vulnerable to resistance interference, resulting in motion stagnation or deviation; limited biocompatibility, some magnetic materials or driving structures may cause in vivo rejection reactions, and long-term safety has not been verified.

[0004] To address the key requirements in the medical field and the bottlenecks of existing technologies, there is an urgent need for a solution that combines high flexibility, multi-degree-of-freedom motion ability, and non-invasive driving. The present invention proposes a design of a soft robot based on multi-directional magnetic control. Through a cross-shaped magnetic unit layout and a magnetic field collaborative control strategy, it breaks through the limitations of existing technologies and provides an innovative solution with high adaptability and low invasiveness for the medical field. Summary of the Invention

[0005] To solve the above problems, the present invention proposes a magnetically controlled soft robot based on a cross-shaped structure composed of five magnetic units. By reasonably designing the magnetic moment directions and structural layouts of each magnetic unit and combining precise control of the external magnetic field, various motion modes can be effectively achieved, including movement in four directions: forward, backward, left, and right.

[0006] The present invention provides a multi-directional moving magnetically controlled soft robot based on magnetic field control. The magnetically controlled soft robot is composed of a central region magnetic unit in the shape of a cube and four surrounding magnetic units in the shape of cubes adhesively connected by an elastomer, forming a flexible cross-shaped structure; The central region magnetic unit is formed by embedding cylindrical magnetic blocks into the elastomer, and the magnetic moment direction is vertically upward perpendicular to the horizontal plane; The surrounding magnetic units are formed by mixing magnetic powder with the elastomer, curing, and horizontal magnetization, and the magnetic moment direction points to the central region along the horizontal plane.

[0007] Preferably, the motion mode of the soft robot is as follows; In the horizontal plane direction, the physical structures and magnetic moment directions of the four surrounding magnetic units are both symmetric, the forces are balanced with each other, and the deformations generated in response to the magnetic field changes perpendicular to the horizontal plane are also the same. Under the action of the magnetic field change in the vertical direction, the soft robot makes a heaving motion in place; The magnetic moment direction of the magnetic units in the central region responds to the change in the horizontal magnetic field, generating a rotational deformation with the center point of the central region magnetic unit as the axis, causing the surrounding magnetic units on one side of the central region magnetic unit to be lifted and the surrounding magnetic units on the other side to be depressed; the lifted surrounding magnetic units push the depressed surrounding magnetic units when falling, thus realizing a peristaltic forward movement in the horizontal direction.

[0008] Preferably, the elastomer is specifically Ecoflex-30 elastomer; the magnetic powder is specifically NdFeB magnetic powder.

[0009] The present invention also provides a driving method for a multi-directional moving magnetically controlled soft robot based on magnetic field control, including the following steps: Use a signal generator to generate a sinusoidal alternating current signal to excite the Helmholtz coil in the Z-axis, generating an alternating magnetic field in the Z-axis direction. Within each cycle of the alternating magnetic field, under the action of the magnetic torque, drive the surrounding magnetic units to perform a cyclic movement of "standing up" - "falling down" - "closing", and then drive the central magnetic unit to perform periodic upward and downward movements; Use the signal generator to output a direct current signal to excite the Helmholtz coil in the X-axis in the horizontal direction, so as to generate a uniform magnetic field in the X-axis direction; The cylindrical magnetic block in the central region magnetic unit generates a deflection in this direction under the action of the uniform magnetic field in the X-axis direction, so that the two surrounding magnetic units arranged oppositely in this direction are unevenly stressed, driving the soft robot to move in the X-axis direction.

[0010] In order to optimize the moving speed, the present invention also proposes a driving method for a multi-directional moving magnetically controlled soft robot based on magnetic field control, including the following steps: Use a signal generator to generate a half-wave alternating current signal to excite the Helmholtz coil in the Z-axis, generating an alternating magnetic field in the Z-axis direction. Within each cycle of the alternating magnetic field, under the action of the magnetic torque, drive the surrounding magnetic units to perform a cyclic movement of "standing up" - "falling down", and then drive the central magnetic unit to perform periodic upward and downward movements; Use the signal generator to output a direct current signal to excite the Helmholtz coil in the X-axis in the horizontal direction, so as to generate a uniform magnetic field in the X-axis direction; The cylindrical magnetic block in the central region magnetic unit generates a deflection in this direction under the action of the uniform magnetic field in the X-axis direction, so that the two surrounding magnetic units arranged oppositely in this direction are unevenly stressed, driving the soft robot to move in the X-axis direction.

[0011] The present invention also provides a preparation method for a multi-directional moving magnetically controlled soft robot based on magnetic field control, including the following steps: S1. Prepare the surrounding magnetic units S1.1. Mix NdFeB magnetic powder with Ecoflex-30 elastomer; S1.2. Stir with a mechanical stirrer to obtain a uniformly mixed colloid; S1.3. Pour the mixed colloid into a cube mold with the same length and width and a thickness less than the length and width, and heat and cure it to obtain a composite elastic block; S1.4. Use a magnetizer to radially magnetize the cured composite elastic block to form magnetic units with a single radially magnetic moment direction; S2. Prepare magnetic units in the central region S2.1. Pour pure Ecoflex elastomer into a cube mold of the same size as in S1.3; S2.2. Embed a cylindrical magnet with a diameter less than the length and width of the cube mold and a height less than the thickness of the cube mold into the exact center of the uncured Ecoflex-30 elastomer; S2.3. Heat and cure to form magnetic units in the central region; S3 Assemble the robot S3.1. Keep the magnetic moment direction of the magnetic units in the central region perpendicular to the horizontal plane upwards, and adhere the sides of the surrounding magnetic units to the sides of the magnetic units in the central region with Ecoflex-30 elastomer in the way that the magnetic moment directions of the surrounding magnetic units point to the central region; S3.2. Heat and cure to complete the assembly of the cross-shaped soft robot.

[0012] Preferably, in S1.2, the mechanical stirrer stirs at a speed of 1500 revolutions per second for 10 minutes; in S1.3, the size of the cube mold is 10 mm×10 mm×1 mm; in S1.4, the pulse voltage of the magnetizer is 2400V; in S2.2, the radius of the cylindrical magnet is 3 mm and the height is 0.5 mm. Beneficial effects

[0013] 1. Multi-degree-of-freedom motion ability: Through the design of five magnetic units and the combination of external magnetic field control, the robot can achieve coordinated motion in multiple directions, thus having strong multi-degree-of-freedom motion ability and being suitable for various task requirements.

[0014] 2. Simple and efficient drive system: The present invention does not rely on traditional pneumatic, electric or hydraulic drive systems, but realizes the motion of the robot through the change of the external magnetic field, avoiding complex internal drive mechanisms and having higher reliability and simplicity.

[0015] 3. High flexibility and adaptability: The robot uses Ecoflex-30 as the main material, which has excellent flexibility and can adapt to complex terrains and narrow spaces. The robot of the present invention can perform tasks in complex environments, has strong adaptability and precision, and the preparation process is simple and efficient, suitable for large-scale manufacturing.

[0016] 4. More advantageous traveling mode: Compared with the rolling traveling mode, the peristaltic traveling mode has advantages such as lower demand for space and higher precision in motion control.

[0017] 5. Simple magnetic field control: There is no need for a complex magnetic field driving strategy to control the traveling direction of the soft robot. Just by changing the directions of the front, rear, left, and right static magnetic fields in the horizontal direction on the basis of maintaining the half-wave magnetic field in the Z direction, the traveling in the four directions of front, rear, left, and right can be achieved. Precise motion control can be realized through external magnetic field control, which is applicable to various fields such as medical assistance, micro-operation, flexible sensing, exploration and repair. Description of the Drawings

[0018] Figure 1 : Schematic diagram of the preparation process of the magnetic unit of the soft robot; Figure 2 : Schematic diagram of the assembly of the soft robot and the magnetic moment distribution; Figure 3 : a is the diagram of the magnetic field applied along the Z-axis changing with time; b is the diagram of the magnetic field applied along the X or Y-axis changing with time; Figure 4 : Schematic diagram of the deformation of the soft robot under the magnetic fields of the X, Y, and Z axes; Figure 5 : a is the physical diagram of the soft robot moving in the +X direction; b is the physical diagram of the soft robot moving in the -X direction; c is the physical diagram of the soft robot moving in the +Y direction; d is the physical diagram of the soft robot moving in the -Y direction. Detailed Embodiment

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] In the present invention, the Z-axis is perpendicular to the horizontal plane direction, and the X-axis and the Y-axis represent two mutually perpendicular axes in the horizontal plane direction, where the X-axis is parallel to the direction of the horizontal bar in the cross-shaped structure of the magnetically controlled soft robot proposed in the present invention.

[0021] A multi-directional magnetically controlled soft robot provided by the present invention, when in a spread state, includes a central magnetic unit and magnetic units evenly distributed around it; the central magnetic unit and the surrounding magnetic units are adhesively assembled and formed by Ecoflex; the surrounding magnetic units of the robot are all magnetized, and the magnetization direction is parallel to the plane where the arm is located when the robot is in a spread state, and is distributed radially and points to the central magnetic unit; the central magnetic unit is formed by embedding a cylindrical magnet into Ecoflex colloid, and the magnetization direction of the magnet is vertically upward.

[0022] In some embodiments, the magnetically controlled soft robot of the present invention is composed of permanent magnetic materials with a scale of micron level and below, such as NdFeB magnetic particles, and elastomer materials, such as silicone, TPE materials, hydrogels, etc. The magnetic unit of the multi-directional magnetically controlled soft robot of the present invention has a square structure, and when the robot is in a spread state, its entire cross-section is in contact with the ground.

[0023] The magnetically controlled soft robot of the present invention is composed of five cube magnetic units to form a cross-shaped structure, where: 1. The magnetic unit in the central area is formed by embedding a cylindrical magnet into Ecoflex-30 elastomer, and the magnetic moment direction is perpendicular to the horizontal plane and upward; 2. The surrounding magnetic units are formed by mixing, curing and horizontally magnetizing NdFeB magnetic powder and Ecoflex-30, and the magnetic moment direction points to the central area along the horizontal plane.

[0024] 3. Each unit is adhesively connected by Ecoflex-30 colloid to form a flexible connection structure.

[0025] The present invention also provides a preparation method for the multi-directional magnetically controlled soft robot, including the following steps S1. Prepare the surrounding magnetic units S1.1. Mix NdFeB magnetic powder and Ecoflex-30 according to a certain mass ratio; S1.2. Stir with a mechanical stirrer at a speed of 1500 revolutions per second for 10 minutes to obtain a uniformly mixed colloid; S1.3. Pour the mixed colloid into a cube mold with dimensions of 10 mm×10 mm×1 mm, and cure it by heating at 90°C for 10 minutes; S1.4. Use a magnetizer to horizontally magnetize the cured composite elastic block under a 2400 pulse voltage to form a magnetic unit with a single horizontal magnetic moment direction.

[0026] S2. Prepare the magnetic unit in the central area S2.1. Pour pure Ecoflex colloid into a cube mold with dimensions of 10 mm×10 mm×1 mm; S2.2. Embed a cylindrical magnet with a radius of 3 mm and a height of 0.5 mm into the uncured Ecoflex-30 colloid; S2.3. Cure by heating at 90 °C for 10 minutes to form a magnetic unit in the central region.

[0027] S3 Assemble the cross-shaped multi-directional crawling robot S3.1. Adhere the surrounding magnetic units to the side of the central region magnetic unit with Ecoflex-30 colloid in such a way that the magnetic moment directions of the surrounding magnetic units point towards the central region; S3.2. Heat at 90 °C to cure the Ecoflex-30 colloid and complete the assembly of the cross-shaped soft robot.

[0028] According to the movement mode of the multi-directional soft robot described in the present invention, different from the tumbling movement of most multi-directional soft robots, the movement mode of the multi-directional soft robot is peristaltic forward movement. The basis of peristaltic forward movement is the uneven force on the front and rear sides in the movement direction. Generally speaking, if there is no cylindrical magnet in the central region, due to the symmetrical structure of the surrounding magnetic units, the deformation responses under the Z-axis magnetic field are basically the same. At this time, the forces on the four magnetic units are uniform, and the overall soft robot only deforms without generating displacement. Thanks to the introduction of the cylindrical magnet in the central region, the soft robot generates uneven forces in the movement direction. The magnet with an axial magnetic moment does not respond to the vertical magnetic field but responds to the horizontal magnetic field. After applying an X or Y direction magnetic field, the magnet deflects in this direction. At the same time, the magnetic units in the same direction are depressed and the magnetic units in the opposite direction are lifted. The forces on the two opposite magnetic units in this direction are uneven. The lifted magnetic unit pushes the depressed magnetic unit when it falls, thus achieving displacement in this direction.

[0029] The present invention also provides a magnetic field regulation method for the multi-directional soft robot described above, including the following steps: Use a signal generator to generate a sinusoidal alternating current signal to excite the Z-axis Helmholtz coil. The Z-axis coil generates a half-wave alternating magnetic field in the Z-axis direction. Under the action of the magnetic torque, the surrounding magnetic units perform a cyclic movement of "standing up" - "falling down" within one period. At this time, the central magnetic unit performs a pitching movement under the action of the surrounding magnetic units. Then use the signal generator to output a direct current signal to excite the X or Y-axis coil in the horizontal direction to generate a uniform magnetic field in the X or Y direction. The cylindrical magnet in the central region deflects in this direction under the action of the horizontal magnetic field, thereby generating uneven forces in this direction. The uneven forces cause the overall soft robot to move in the direction of the applied magnetic field.

[0030] Preferably, the movement of the multi-directional soft robot depends on the interaction between the surrounding magnetic units and the ground. When the surrounding magnetic units perform the "closing" movement, the soft robot does not move. The extra "closing" action will slow down the traveling speed of the soft robot. If a half-wave alternating current signal is used to replace the sine wave signal, the surrounding magnetic units only perform a cyclic movement of "standing up" - "falling down", and the surrounding magnetic units always interact with the ground, improving the traveling speed of the soft robot.

[0031] The present invention also provides a method for driving the multi-directional magnetically controlled soft robot to travel in four directions, including the following steps: laying the soft robot flat on the working plane, applying an alternating magnetic field with half-wave excitation in the Z-axis direction, and the surrounding magnetic units perform a cyclic movement of "standing up" - "falling down". Then, applying a +X-axis static magnetic field, the magnetic block in the central area deflects in the +X direction, causing the magnetic units in the +X direction to be less stressed than those in the -X direction. During the "falling" process, the magnetic units in the -X direction push the magnetic units in the +X direction forward to complete the traveling displacement in the +X direction. Similarly, replacing the horizontal static magnetic field with a -X-axis direction static magnetic field, the soft robot moves in the -X direction; replacing the horizontal static magnetic field with a +Y-axis direction static magnetic field, the soft robot moves in the +Y direction; replacing the horizontal static magnetic field with a -Y-axis direction static magnetic field, the soft robot moves in the -Y direction.

[0032] The following are specific embodiments: As Figure 2 shown, both the central and surrounding magnetic units of the multi-directional magnetically controlled soft robot are squares with a side length of 10 mm. The surrounding magnetic units are made by uniformly mixing and curing NdFeB particles and Ecoflex-30. The central area is a cured Ecoflex colloid embedded with a cylindrical magnetic block with a radius of 3 mm and a height of 0.5 mm. The entire robot has a thickness of 1 mm; all the surrounding magnetic units are magnetized, and the magnetization direction is parallel to the plane where the arms are located and points radially towards the central area. The magnetization direction of the cylindrical magnetic block in the central area is vertically upward.

[0033] Lay the soft robot flat on the working plane and apply a half-wave excitation magnetic field as shown in Figure 3 a. The surrounding magnetic units perform a cyclic movement of "standing up" - "falling down" as shown in Figure 4 . Then, apply a +X-axis static magnetic field. The magnetic block in the central area deflects in the +X direction, causing the magnetic units in the +X direction to be less stressed than those in the -X direction. During the "falling" process, the magnetic units in the -X direction push the magnetic units in the +X direction forward to complete the traveling displacement in the +X direction as shown in Figure 5 a. Similarly, replacing the horizontal static magnetic field with a -X-axis direction static magnetic field, the soft robot moves in the -X direction as shown in Figure 5as shown in b; when the horizontal static magnetic field is replaced with a static magnetic field in the +Y-axis direction, the soft robot moves in the +Y direction as Figure 5 shown in c; when the horizontal static magnetic field is replaced with a static magnetic field in the -Y-axis direction, the soft robot moves in the -Y direction as Figure 5 shown in d.

Claims

1. A multi-directional moving magnetically controlled soft robot based on magnetic field control, characterized in that The magnetically controlled soft robot is composed of a central region magnetic unit in the shape of a cube and four peripheral magnetic units in the shape of cubes, which are adhered by an elastomer to form a flexible cross-shaped structure; The central region magnetic unit is formed by embedding cylindrical magnets into the elastomer, and the magnetic moment direction is perpendicular to the horizontal plane and upward; The peripheral magnetic units are formed by mixing, curing and horizontally magnetizing magnetic powder and the elastomer, and the magnetic moment direction points to the central region along the horizontal plane.

2. The multi-directional moving magnetically controlled soft robot based on magnetic field control according to claim 1, wherein The movement mode of the soft robot is as follows; In the horizontal plane direction, the physical structures and magnetic moment directions of the four peripheral magnetic units are both symmetric, the forces are balanced with each other, and the deformations generated in response to the magnetic field changes perpendicular to the horizontal plane are also the same. Under the action of the magnetic field changes in the vertical direction, the soft robot undulates in place; The magnetic moment direction of the central region magnetic unit responds to the magnetic field changes in the horizontal plane direction, generating a rotational deformation with the center point of the central region magnetic unit as the axis, so that one side of the peripheral magnetic units of the central region magnetic unit is lifted and the other side of the peripheral magnetic units is depressed; the lifted peripheral magnetic units push the depressed peripheral magnetic units when falling, thus realizing a peristaltic forward movement in the horizontal direction.

3. The multi-directional moving magnetically controlled soft robot based on magnetic field control according to claim 1, wherein The elastomer is specifically Ecoflex-30 elastomer; the magnetic powder is specifically NdFeB magnetic powder.

4. The driving method of a multi-directional moving magnetically controlled soft robot based on magnetic field control according to claim 2, wherein, It includes the following steps: Use a signal generator to generate a sinusoidal alternating current signal to excite the Helmholtz coil on the Z axis, generating an alternating magnetic field in the Z axis direction. Within each alternating magnetic field cycle, under the action of the magnetic torque, drive the peripheral magnetic units to perform a cyclic movement of "standing up" - "falling down" - "closing", and then drive the central magnetic unit to perform periodic upward and downward movements; Use a signal generator to output a direct current signal to excite the Helmholtz coil on the X axis in the horizontal direction, so as to generate a uniform magnetic field in the X axis direction; The cylindrical magnet in the central region magnetic unit generates a deflection in this direction under the action of the uniform magnetic field in the X axis direction, so that the two relatively arranged peripheral magnetic units in this direction are unevenly stressed, driving the soft robot to move in the X axis direction.

5. The driving method of a multi-directional moving magnetically controlled soft robot based on magnetic field control according to claim 2, characterized in that, It includes the following steps: Use a signal generator to generate a half-wave alternating current signal to excite the Helmholtz coil on the Z axis, generating an alternating magnetic field in the Z axis direction. Within each alternating magnetic field cycle, under the action of the magnetic torque, drive the peripheral magnetic units to perform a cyclic movement of "standing up" - "falling down", and then drive the central magnetic unit to perform periodic upward and downward movements; Use a signal generator to output a direct current signal to excite the Helmholtz coil on the X axis in the horizontal direction, so as to generate a uniform magnetic field in the X axis direction; The cylindrical magnet in the central region magnetic unit generates a deflection in this direction under the action of the uniform magnetic field in the X axis direction, so that the two relatively arranged peripheral magnetic units in this direction are unevenly stressed, driving the soft robot to move in the X axis direction.

6. The preparation method of a multi-directionally movable magnetically controlled soft robot based on magnetic field control according to claim 2, characterized in that, It includes the following steps: S1. Prepare the peripheral magnetic units S1.

1. Mix NdFeB magnetic powder and Ecoflex-30 elastomer; S1.

2. Stir with a mechanical stirrer to obtain a uniformly mixed colloid; S1.

3. Pour the mixed colloid into a cube mold with the same length and width and a thickness less than the length and width, and heat and cure it to obtain a composite elastic block; S1.

4. Use a magnetizer to radially magnetize the cured composite elastic block to form magnetic units with a single radially magnetic moment direction; S2. Prepare magnetic units in the central region S2.

1. Pour pure Ecoflex elastomer into a cube mold of the same size as in S1.3; S2.

2. Embed a cylindrical magnet with a diameter less than the length and width of the cube mold and a height less than the thickness of the cube mold into the exact center of the uncured Ecoflex-30 elastomer; S2.

3. Heat and cure to form magnetic units in the central region; S3 Assemble the robot S3.

1. Keep the magnetic moment direction of the magnetic units in the central region perpendicular to the horizontal plane and pointing upward. Adhere the sides of the magnetic units around to the sides of the magnetic units in the central region with Ecoflex-30 elastomer in the way that the magnetic moment directions of the magnetic units around point to the central region; S3.

2. Heat and cure to complete the assembly of the soft robot with a cross-shaped structure.

7. The preparation method according to claim 6, characterized in that: In S1.2, the mechanical stirrer stirs at a speed of 1500 revolutions per second for 10 minutes; In S1.3, the size of the cube mold is 10 mm×10 mm×1 mm; In S1.4, the pulse voltage of the magnetizer is 2400V; In S2.2, the radius of the cylindrical magnet is 3 mm and the height is 0.5 mm.

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