A jellyfish-like magnetic soft robot

Abstract

The present invention provides a magnetic soft robot that mimics a jellyfish. The robot comprises an outer membrane, an inner membrane, a porous base, an electromagnetic coil, an iron core, and biomimetic tentacles. The outer membrane and inner membrane are hemispherical, with their axes coinciding. The outer membrane, inner membrane, and biomimetic tentacles are made of a magnetorheological elastomer. The porous base is disc-shaped. The iron core is fixed to the center of the porous base. The electric coil is wound around the iron core, generating a magnetic field with a variable direction when energized. The shape of the magnetic variable elastomer changes with the direction of the magnetic field. The biomimetic tentacle is mounted on the lower surface of the porous base and assists the soft robot in moving according to the deformation of the magnetic variable elastomer. The outer membrane, inner membrane, and porous base form a cavity with a variable volume. The cavity expands or contracts in response to the deformation of the magnetic variable elastomer, mimicking the principle of a jellyfish's water absorption and drainage. The magnetic soft robot has a simple structure and a fast response speed.

Description

Technical Field

[0001] The present invention belongs to the field of magnetically controlled bionic robots, and more specifically, relates to a soft robot whose magnetorheological elastomer imitates the movement of jellyfish. Background Art

[0002] Compared to traditional rigid robots, soft robots have no restrictions on degrees of freedom and possess exceptional flexibility and pliability, offering broad application prospects in a wide range of fields, particularly biomimetic research. Because the jellyfish's swimming mechanism is simple and easily implemented, and jellyfish-like robots can be used in a wide range of applications, including underwater inspection and ocean exploration, a significant amount of research has been conducted on jellyfish-like soft robots. Existing actuation mechanisms include fluid actuation, shape memory alloy actuation, electroactive polymer actuation, and magnetorheological actuation. Magnetorheological actuation, for example, can reversibly alter its mechanical, electrical, and magnetic properties by adjusting the magnitude and direction of a magnetic field. Its fast response and excellent reversibility make it well-suited for soft robot actuation. Therefore, there is a need to design a magnetic-field-driven, jellyfish-like magnetic soft robot. Summary of the Invention

[0003] In view of the defects of the existing technology, the purpose of the present invention is to provide a jellyfish-like magnetic soft robot, aiming to solve the problems of complex structure and slow movement speed of underwater soft robots.

[0004] In order to achieve the above object, the present invention provides a jellyfish-like magnetic soft robot driven by a magnetic field, comprising: an outer membrane, an inner membrane, a porous medium bottom plate, an electromagnetic coil, an iron core and bionic tentacles;

[0005] The porous medium bottom plate is disc-shaped, and the holes on the medium plate are channels for absorbing and draining water, and can also effectively filter impurities in the water;

[0006] The iron core is placed above the porous medium bottom plate, and the center of the iron core coincides with the center of the porous medium bottom plate;

[0007] The electromagnetic coil is wound around the iron core, and when the coil is energized, a driving magnetic field with variable direction is generated, and the magnetic lines of force of the driving magnetic field are concentrated in the center and diverge around; the magnetic moment of the magnetic particles inside the magnetic soft robot tends to deflect in the direction of the driving magnetic field to generate a magnetic torque; the magnetic moment of the magnetic particles inside the magnetic soft robot is centrally symmetrically distributed;

[0008] The outer film is made of magnetorheological elastomer material composed of elastic matrix and high coercive force and high hysteresis magnetic particles;

[0009] The magnetization direction of the outer film is the thickness direction, and the polarity of the inner surface and the outer surface of the outer film are opposite;

[0010] The inner film is made of magnetorheological elastomer material composed of elastic matrix and high magnetic permeability and low hysteresis magnetic particles;

[0011] The bionic tentacle is made of a magnetorheological elastomer material consisting of an elastic matrix and high coercive force and high hysteresis magnetic particles;

[0012] The bionic tentacle is magnetized in the longitudinal direction, and the polarities of the upper and lower ends of the bionic tentacle are opposite;

[0013] The lower ends of the outer membrane and the inner membrane are fixed to the upper surface of the porous medium bottom plate, and the three form a cavity. The volume of the cavity changes according to the deformation of the outer membrane and the inner membrane. The increase in the volume of the cavity corresponds to the jellyfish model absorbing water, and the decrease in the volume of the cavity corresponds to the jellyfish model draining water.

[0014] The bionic tentacles are fixed on the lower surface of the porous medium bottom plate, the upper ends of the bionic tentacles are gathered and retracted at the center of the porous medium bottom plate, and the lower ends of the bionic tentacles are bent inwards.

[0015] When the electromagnetic coil is energized, it can generate a direction-variable driving magnetic field, which rapidly magnetizes the inner membrane. The magnetic field inside the inner membrane is along the thickness direction;

[0016] The magnetic field generated by the electromagnetic coil magnetizes the inner membrane. The polarity of the outer surface of the inner membrane is opposite to the polarity of the inner surface of the magnetized outer membrane. The inner membrane and the outer membrane attract each other, and the volume of the cavity formed by the inner membrane, the outer membrane and the porous medium bottom plate decreases. The water molecules inside the soft robot are discharged to the outside through the porous medium bottom plate, generating a forward thrust, and the soft robot swims forward.

[0017] Optionally, the magnetic field generated by the electromagnetic coil magnetizes the inner membrane, the polarity of the outer surface of the inner membrane is the same as the polarity of the inner surface of the magnetized outer membrane, the inner membrane and the outer membrane repel each other, the volume of the cavity formed by the inner membrane, the outer membrane and the porous medium bottom plate increases, and water molecules outside the soft robot enter the interior of the soft robot through the porous medium bottom plate;

[0018] When the direction of the magnetic field generated by the electromagnetic coil is the same as the magnetization direction of the bionic tentacle, the upper end of the bionic tentacle and the electromagnetic coil repel each other, and the bionic tentacles disperse and spread outward. This action is synchronized with the water absorption state of the soft robot.

[0019] Optionally, when the direction of the magnetic field generated by the electromagnetic coil is opposite to the magnetization direction of the bionic tentacle, the upper end of the bionic tentacle and the electromagnetic coil attract each other, and each bionic tentacle retracts inward, generating a backward thrust, and the reaction force causes the robot to swim forward. This action is synchronized with the drainage state of the soft robot.

[0020] The jellyfish-like soft robot's movements are divided into two phases: S1 – water drainage; S2 – water absorption. In S1, the direction of the magnetic field generated by the electromagnetic coil causes the outer membrane to contract inward, and the bionic tentacles to fold inward, generating a backward thrust that propels the soft robot forward. In S2, the electromagnetic coil generates a magnetic field in the opposite direction, causing the outer membrane to expand, the bionic tentacles to disperse outward, and the soft robot to return to its water-filled state. The electromagnetic coil generates a variable-direction magnetic field, driving S1 and S2 alternately, achieving autonomous movement of the jellyfish-like soft robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the composition of the jellyfish-imitation soft robot of the present invention.

[0022] Figure 2 This is a schematic diagram of the S1 stage - drainage of the jellyfish-like soft robot of the present invention.

[0023] Figure 3 This is a schematic diagram of the jellyfish-like soft robot of the present invention in stage S2 - water absorption.

[0024] Explanation of the main component symbols: 1-water, 2-iron core, 3-electromagnetic coil, 4-outer membrane, 5-inner membrane, 6-porous medium bottom, 7-bionic tentacle. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] The present invention provides a jellyfish-like magnetic soft robot that achieves speed-controlled underwater motion. The magnetic soft robot comprises an outer membrane 4, an inner membrane 5, a porous substrate 6, an electromagnetic coil 3, an iron core 2, and biomimetic tentacles 7. The outer membrane 4 and biomimetic tentacles 7 are made of a magnetorheological elastomer material consisting of an elastic matrix and high-coercivity, high-hysteresis magnetic particles, while the inner membrane 5 is made of a magnetorheological elastomer material consisting of an elastic matrix and high-permeability, low-hysteresis magnetic particles. The driving method is briefly described as follows: the direction of the driving magnetic field is controlled by the direction of the current, magnetizing the low-hysteresis inner membrane 5. By utilizing the magnetic pole properties of the magnet (the principle that like poles repel and opposite poles attract), the soft robot is controlled to simulate the natural "water absorption and drainage" and tentacle-swinging swimming patterns of jellyfish. This invention addresses the shortcomings of conventional driving modes, such as the large size, complex structure, and slow motion of the soft robot and its driving device.

[0027] In view of the defects of the existing technology, the purpose of the present invention is to solve the problems of limited driving flexibility, single driving mode, complex structure, slow movement speed and slow response of soft robots at the current stage.

[0028] Please refer to the following Figure 1 A schematic diagram of the composition of a jellyfish-like magnetic soft robot provided by the present invention is described; Figure 1 As shown, the jellyfish-like magnetic soft robot consists of six major parts: an outer membrane 4, an inner membrane 5, a porous medium bottom plate 6, bionic tentacles 7, an iron core 2, and an electromagnetic coil 3.

[0029] The iron core 2 is fixed at the center of the porous medium bottom plate 6, and the upper end of the iron core 2 is fixed to the lower surface of the inner membrane 5; the electromagnetic coil 3 is wound around the iron core 2, and generates a dynamic magnetic field with variable direction when energized.

[0030] The inner membrane 5 is hemispherical, and the end ring is connected to the upper surface of the porous medium bottom plate 6. The magnetic properties of the inner membrane 5 with high magnetic permeability and low magnetic hysteresis make it extremely easy to be magnetized by the magnetic field. When the direction of the external dynamic magnetic field changes, its internal magnetic field also responds quickly to the change of magnetic poles.

[0031] The outer membrane 4 is hemispherical, and the end ring is connected to the upper surface of the porous medium bottom plate 6 with the same radius. The magnetic properties of high coercive force and high hysteresis make it have strong remanence after magnetization. The static magnetic field interacts with the dynamic magnetic field formed by the inner membrane 5 to achieve the effect of water absorption and drainage.

[0032] The upper end of the bionic tentacle 7 is centrally connected to the vicinity of the center of the porous medium bottom plate 6, which is within the circumference of the electromagnetic coil 3. The lower end of the bionic tentacle 7 is naturally bent inward. The high coercive force and high hysteresis magnetic properties of the bionic tentacle 7 make it have a strong residual magnetism after being magnetized. The static magnetic field interacts with the driving magnetic field generated by the electromagnetic coil 3 to achieve the effect of swinging and swimming.

[0033] like Figure 1 As shown, the magnetization direction of the outer film 4 is along the thickness direction, the polarity of the outer surface of the outer film 4 is the S pole, and the polarity of the inner surface of the outer film 4 is the N pole.

[0034] like Figure 1 As shown, the magnetization direction of the bionic tentacle 7 is along the length direction, the polarity of the end of the bionic tentacle 7 close to the porous medium bottom plate 6 is the S pole, and the polarity of the distal end is the N pole.

[0035] Specifically, by changing the direction of the current in the electromagnetic coil 3, the size and direction of the internal driving magnetic field of the jellyfish-like magnetic soft robot are regulated. The outer membrane 4 and the inner membrane 5 of the soft robot are subjected to an asymmetric magnetic torque. Taking the force conditions into consideration, the outer membrane 4 expands and the inner membrane 5 contracts, or the outer membrane 4 contracts and the inner membrane 5 expands, realizing a movement mode that simulates the "water drainage-water absorption" swimming of the jellyfish.

[0036] Specifically, by changing the direction of the current in the electromagnetic coil 3, the size and direction of the internal driving magnetic field of the jellyfish-like magnetic soft robot are regulated, and the proximal and distal ends of the soft robot's bionic tentacle 7 are subjected to asymmetric magnetic torques. Taking the force conditions into comprehensive consideration, the bionic tentacle 7 swings back and forth to achieve a motion mode that simulates the swinging and swimming of the jellyfish tentacle.

[0037] like Figure 2 As shown, the driving magnetic field generated by the electromagnetic coil has an S pole at the top and an N pole at the bottom. This rapidly magnetizes the inner membrane of the soft robot, with the magnetic field radiating outward along the hemispherical radius of the inner membrane. The direction of the magnetic field on the outer membrane of the soft robot is the same as that on the inner membrane. Based on the magnetic principle of "opposites attract," the outer membrane of the magnetorheological elastomer, formed by the elastic matrix, begins to contract inward under the magnetic force, while the inner membrane of the magnetorheological elastomer, also formed by the elastic matrix, begins to expand outward under the magnetic force. As the volume of the jellyfish-like magnetic soft robot decreases, the internal pressure becomes greater than the external pressure. Water molecules inside the cavity are discharged through the porous medium bottom plate. The outer membrane deforms and recovers, accelerating the "drainage" action. When the forward thrust Ft exceeds the friction force Ff of the water on the soft robot, the soft robot moves forward. At the same time, the magnetic field generated by the electromagnetic coil attracts the north pole of the proximal south pole of the biomimetic tentacle. The magnetorheological elastomer composed of the elastic body begins to gather together under the influence of the magnetic force. The proximal end pulls the biomimetic tentacle tip inward, shrinking the space between the tentacles. The water in between is squeezed out backward, generating forward thrust and moving the soft robot forward. At this point, the jellyfish-like magnetic soft robot is in the "forward" state.

[0038] like Figure 3 As shown, when the dynamic magnetic field generated by the electromagnetic coil has an N pole at its upper end and an S pole at its lower end, the inner membrane of the soft robot rapidly magnetizes, with the magnetic field radiating outward along the inner membrane's hemisphere. The direction of the outer magnetic field of the soft robot's outer membrane is opposite to that of the inner membrane. Based on the magnetic principle of "like charges repel like," the outer membrane of the magnetorheological elastomer, composed of an elastic matrix, begins to expand outward under the magnetic force, while the inner membrane of the magnetorheological elastomer, also composed of an elastic matrix, begins to contract inward under the magnetic force. The volume of the jellyfish-like magnetic soft robot's cavity increases, and the internal pressure decreases below the external pressure. Water molecules enter the cavity through the porous substrate, completing the "water absorption" action. Simultaneously, the S pole of the magnetic field generated by the electromagnetic coil repels the S pole at the proximal end of the biomimetic tentacle. The magnetorheological elastomer, composed of the elastic matrix, begins to disperse under the magnetic force, pulling the proximal end of the biomimetic tentacle outward, widening the space between the tentacles. At this point, the jellyfish-like magnetic soft robot enters a "stagnant" state, creating conditions for the next water discharge.

[0039] The present invention proposes a jellyfish-like magnetic soft robot, which solves the shortcomings of the traditional driving mode, such as large size, complex structure, slow movement speed, and slow response of underwater soft robots and driving devices, and realizes the speed-controlled forward movement of the jellyfish-like magnetic soft robot. Figure 2 and Figure 3 As shown in the figure, the motion mode of "water absorption and drainage" of jellyfish is simulated.

[0040] It is understandable that the head and tail of the jellyfish-like magnetic soft robot can be driven forward. Through a special magnetization method, the "drainage" and "tail swinging" actions of the soft robot are made consistent, greatly reducing energy loss.

[0041] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A jellyfish-like magnetic soft robot, characterized by: It includes water (1), an iron core (2), an electromagnetic coil (3), an outer membrane (4), an inner membrane (5), a porous medium bottom plate (6), and a bionic tentacle (7); The outer membrane (4) and the inner membrane (5) are both hemispherical and have the same center. The porous medium bottom plate (6) is circular. The lower end ring of the outer membrane (4) is fixedly connected to the upper surface of the porous medium bottom plate (6) concentrically and the radius is equal. The lower end ring of the inner membrane (5) is fixedly connected to the porous medium bottom plate (6) concentrically and the radius of the lower end ring of the inner membrane (5) is half of the radius of the lower end ring of the outer membrane (4). The outer membrane (4), the inner membrane (5) and the porous medium bottom plate (6) form a cavity with a variable volume. The electromagnetic coil (3) is wound on the outer cylindrical surface of the iron core (2), the upper surface of the iron core (2) is fixedly connected to the inner membrane (5), the lower surface of the iron core (2) is fixedly connected to the porous medium bottom plate (6), and the center of the lower surface of the iron core (2) coincides with the center of the upper surface of the porous medium bottom plate (6); The bionic tentacle (7) is fixedly connected to the lower surface of the porous medium bottom plate (6), and the connection position of the bionic tentacle (7) and the porous medium bottom plate (6) is located within a circular range with the center of the lower surface of the porous medium bottom plate (6) as the center and the radius of the electromagnetic coil (3) as the radius; When the electromagnetic coil (3) is energized, a driving magnetic field is provided inside the magnetic soft robot, wherein the magnetic lines of force of the driving magnetic field are concentrated in the center and diverge in the surrounding areas; the magnetic moments of the magnetic particles in the outer membrane (4), the inner membrane (5) and the bionic tentacle (7) of the magnetic soft robot tend to deflect in the direction of the driving magnetic field, thereby generating a magnetic torque; the direction of the driving magnetic field changes to control the volume of the cavity and the bionic tentacle (7), thereby driving the soft robot forward.

2. The jellyfish-like magnetic soft robot according to claim 1, characterized in that: The outer film (4) is made of a magnetorheological elastomer material composed of an elastic matrix and high-coercive force and high-hysteresis magnetic particles.

3. The jellyfish-like magnetic soft robot according to claim 2, characterized in that: The magnetization direction of the outer film (4) is the thickness direction.

4. The jellyfish-like magnetic soft robot according to claim 1, wherein: The inner film (5) is made of a magnetorheological elastomer material composed of an elastic matrix and high-permeability and low-hysteresis magnetic particles.

5. The jellyfish-like magnetic soft robot according to claim 1, characterized in that: The bionic tentacle (7) is in the shape of an elongated strip. In a natural state, the bionic tentacle (7) is in an inwardly curved shape. The cross section of the bionic tentacle (7) is circular. The bionic tentacle (7) is made of a magnetorheological elastomer material composed of an elastic matrix and high coercive force and high hysteresis magnetic particles.

6. The jellyfish-like magnetic soft robot according to claim 5, characterized in that: The magnetization direction of the bionic tentacle (7) is the length direction.

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