A micro artificial muscle actuator capable of bidirectional bending and deformation and its preparation method

Abstract

The present invention relates to the field of micro-actuator technology, specifically disclosing a bidirectionally bendable micro-artificial muscle actuator and a method for preparing the same. The bidirectionally bendable micro-artificial muscle actuator comprises an elastic substrate, a nickel anchoring structure, an SMA filament, a photolithographic array structure, and a PDMS flexible layer. The nickel anchoring structure, the SMA filament, and the photolithographic array structure are symmetrically arranged on the upper and lower sides of the elastic substrate. The photolithographic array structure is arranged in multiple columns, and the SMA filaments are arranged in multiple rows and perpendicularly pass through the photolithographic array structure to form a mesh structure with the SMA filaments. The nickel anchoring structures are located at both ends of the SMA filaments, and the PDMS flexible layer is cast in the gaps of the mesh structure. The present invention selects a lightweight, high-strength substrate material and uses micromachining technology to prepare a miniaturized, lightweight, and high-energy-density bidirectionally bendable micro-artificial muscle actuator.

Description

Technical Field

[0001] The present invention relates to the technical field of micro actuators, and in particular to a micro artificial muscle actuator capable of bidirectional bending and deformation and a preparation method thereof. Background Art

[0002] As the size of robots decreases, traditional mechanical systems and processing and manufacturing processes will encounter many technical bottlenecks, especially the choice of drive mode. The traditional motor-driven system is heavy and cannot be further miniaturized, which limits the development of micro robots. Currently, micro drives have technical bottlenecks such as small deformation size, small output force, and large mass. Summary of the Invention

[0003] The purpose of the present invention is to provide a micro artificial muscle actuator capable of bidirectional bending and deformation and a preparation method thereof, so as to solve the problems of small deformation size, small output force and large mass of the micro actuator in the prior art.

[0004] In order to solve the above technical problems, the present invention provides a micro-artificial muscle actuator that can be bent and deformed in both directions, including an elastic substrate, a nickel anchoring structure, an SMA wire, a photolithography array structure and a PDMS flexible layer. The nickel anchoring structure, the SMA wire and the photolithography array structure are symmetrically arranged on the upper and lower sides of the elastic substrate. The photolithography array structure is multi-column, the SMA wire is multi-row and vertically passes through the photolithography array structure to form a mesh structure with it, the nickel anchoring structure is located at both ends of the SMA wire, and the PDMS flexible layer is cast in the gaps of the mesh structure.

[0005] Preferably, the elastic substrate includes a carbon fiber layer and a glass fiber structure, the glass fiber structure is symmetrically arranged on the upper and lower sides of the carbon fiber layer, the glass fiber structure and the nickel anchoring structure are the same in number and corresponding in position, and the carbon fiber layer is a plate with a hollow structure.

[0006] Preferably, a nickel anchoring structure is provided at each midpoint of the upper and lower sides of the elastic base.

[0007] A method for preparing a micro artificial muscle actuator capable of bidirectional bending and deformation comprises the following steps:

[0008] S1. preparing an elastic substrate;

[0009] S1-1. Use a UV laser cutting machine to process the carbon fiber layer and the glass fiber structure into a plate shape, and set the glass fiber structure symmetrically on the upper and lower sides of the carbon fiber layer;

[0010] S1-2, placing the carbon fiber layer and the glass fiber structure in a high-pressure and high-temperature box, setting the pressure, temperature, and curing time. After the high-temperature and high-pressure treatment, the carbon fiber layer and the glass fiber structure are tightly cured and bonded to form an elastic substrate;

[0011] S2, preparing SMA wire;

[0012] S2-1. Perform a tensile test on the SMA wire at room temperature to determine the stress P at which the SMA wire undergoes a complete martensitic phase transformation. Apply stress P to the SMA wire and perform thermal training. Apply electricity to heat it to shrink it, then cool it to restore it to its original shape, and repeat the heating and cooling process multiple times.

[0013] S2-2, sputtering TiW layer and Ni layer next to the glass fiber structure;

[0014] S2-3. The SMA wires prepared above are symmetrically arranged on the upper and lower sides of the elastic substrate, and fixed by a temporary support structure so that a certain distance is maintained between the SMA wires and the elastic substrate.

[0015] S3, preparing nickel anchoring structure;

[0016] S3-1, take the photoresist and put it into a vacuum box to evacuate the vacuum, and pour the vacuumized photoresist on the substrate obtained in step S2;

[0017] S3-2, using a coating machine to coat the substrate with photoresist to obtain a first photoresist layer, placing the substrate coated with photoresist on a heating plate and baking it at a temperature lower than the phase transition temperature of the SMA wire, and exposing it using a maskless photolithography machine after natural cooling to obtain an exposure pattern;

[0018] S3-3, drawing an exposure pattern and copying it into a maskless photolithography machine, and after specifying an exposure dose, transferring the drawn exposure pattern onto a substrate coated with a photoresist to obtain an exposed substrate;

[0019] S3-4, baking the exposed substrate on a hot plate, and developing it in a photoresist developer after cooling, and taking it out after a certain period of development, leaving the solidified photoresist on the substrate;

[0020] S3-5, immersing the substrate in a mixed solution of HF and H2O to remove the oxide layer of the SMA wire and the oxide layer of the Ni layer;

[0021] S3-6, electroplating nickel in the area where the photoresist has fallen off to form a nickel anchoring structure, and peeling off the remaining solidified photoresist;

[0022] S4, preparing a photolithographic array structure;

[0023] S4-1, take the photoresist and put it into a vacuum box to evacuate the vacuum, pour the vacuumized photoresist on the substrate obtained in step S3, and use a spin coater to spin-coat the photoresist to obtain a second photoresist layer;

[0024] S4-2, repeating steps S3-2 to S3-4 to form a photolithographic array structure on the substrate, wherein the SMA wire, the nickel anchoring structure and the photolithographic array structure form a network structure;

[0025] S5. Use a coating machine to spin-coat PDMS on the substrate so that the PDMS fills the gaps in the mesh structure to obtain a PDMS flexible layer;

[0026] S6. Remove the temporary support structure of the substrate and cut off the excess SMA wires at both ends to obtain a micro artificial muscle actuator that can bend and deform in both directions.

[0027] Preferably, in step S2-1, the substrate is cleaned with an alcohol brush, impurities are cut with a laser, rinsed with pure water, blown clean with high-purity nitrogen, and then immersed in an acetone solution, and then placed in an ultrasonic cleaning machine for vibration washing. After being taken out, it is rinsed with anhydrous ethanol, rinsed with pure water, and then blown clean with high-purity nitrogen to obtain a substrate with a clean surface.

[0028] Preferably, in step S3-2, the speed of the coating machine is first set according to the photoresist technical document to obtain a photoresist layer of a certain thickness, which is then placed on a heating plate and baked at 65°C for 1 minute, 80°C for 2 minutes, and 65°C for 1 minute. The photoresist is spin-coated again and baked repeatedly until the photoresist is evenly coated on the substrate to obtain a first photoresist layer.

[0029] Preferably, in step S3-4, if there are areas where the development is not uniform and the photoresist remains, use a micro syringe to draw up the developer and gently spray it, then rinse it with pure water, and place the rinsed substrate on a hot plate and bake it at 85°C for 5 minutes.

[0030] Preferably, in step S1-2, the pressure is set to 1000KG / m 2 , temperature 120 ° C, curing for 2 hours, in step S2-1, the thermal training cycle is 1000 times of heating and cooling process, in step S3-5, the mixing ratio of HF and H2O mixed solution is 1:10.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention selects lightweight, high-strength carbon fiber and glass fiber as the base material, and uses micro-machining technologies such as ultraviolet laser cutting and photolithography to achieve the design and manufacture of a miniaturized, lightweight, high-energy-density, bidirectionally bendable micro-artificial muscle actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic structural diagram of a micro artificial muscle actuator capable of bidirectional bending and deformation according to an embodiment of the present invention;

[0034] Figure 2 Schematic diagram of a single carbon fiber prepreg and a single glass fiber prepreg after cutting according to an embodiment of the present invention;

[0035] Figure 3 for Figure 2 Front view of

[0036] Figure 4 This is a schematic diagram of an elastic substrate formed after curing the prepreg according to an embodiment of the present invention;

[0037] Figure 5 for Figure 4 Front view of

[0038] Figure 6 Schematic diagram of fixing SMA wire using a temporary support structure according to an embodiment of the present invention;

[0039] Figure 7 for Figure 6 Front view of

[0040] Figure 8 This is a schematic diagram of spin coating a first photoresist layer according to an embodiment of the present invention;

[0041] Figure 9 for Figure 8 Front view of

[0042] Figure 10 A schematic diagram of a portion of the first photoresist layer being removed by development according to an embodiment of the present invention;

[0043] Figure 11 for Figure 9 Front view of

[0044] Figure 12 Schematic diagram of nickel electroplating according to an embodiment of the present invention;

[0045] Figure 13 for Figure 12 Front view of

[0046] Figure 14 This is a schematic diagram of stripping cured photoresist according to an embodiment of the present invention;

[0047] Figure 15 for Figure 14 Front view of

[0048] Figure 16 This is a schematic diagram of spin coating a second photoresist layer according to an embodiment of the present invention;

[0049] Figure 17 for Figure 16 Front view of

[0050] Figure 18 A schematic diagram of a photolithography array structure formed according to an embodiment of the present invention;

[0051] Figure 19 for Figure 18 Front view of

[0052] Figure 20This is a schematic diagram of pouring PDMS to form a PDMS flexible layer according to an embodiment of the present invention;

[0053] Figure 21 for Figure 20 Front view of .

[0054] In the figure, 1, elastic substrate; 101, carbon fiber layer; 102, glass fiber structure; 103, TiW layer; 104, Ni layer; 2, nickel anchoring structure; 201, first photoresist layer; 202, cured photoresist; 203, second photoresist layer; 3, SMA wire; 301, temporary support structure; 4, photolithography array structure; 5, PDMS flexible layer DETAILED DESCRIPTION

[0055] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0056] A micro artificial muscle actuator capable of bidirectional bending and deformation, such as Figure 1 As shown, it includes an elastic substrate 1, a nickel anchoring structure 2, an SMA wire 3, a photolithography array structure 4 and a PDMS flexible layer 5. The nickel anchoring structure 2, the SMA wire 3 and the photolithography array structure 4 are symmetrically arranged on the upper and lower sides of the elastic substrate 1. The photolithography array structure 4 is in multiple columns, and the SMA wire 3 is in multiple rows and vertically passes through the photolithography array structure 4 to form a mesh structure with it.

[0057] The elastic base 1 includes a carbon fiber layer 101 and a glass fiber structure 102. The thickness of the carbon fiber layer 101 and the glass fiber structure 102 can be selected between tens of microns. The carbon fiber layer 121 has the mechanical property of a high elastic modulus, providing support and rebound deformation for the entire micro-artificial muscle actuator. The glass fiber structure 102 has high strength and insulation function, and serves as the base of the nickel anchoring structure 2. The glass fiber structure 102 is evenly and symmetrically arranged on the upper and lower sides of the carbon fiber layer 101. The glass fiber structure 102 is the same in number and position as the nickel anchoring structure 2. The carbon fiber layer 101 is a plate with a hollow structure.

[0058] There are three nickel anchoring structures 2 on each side of the elastic substrate 1, with two nickel anchoring structures 2 on each side located at both ends of the SMA wire 3, and the remaining nickel anchoring structure 2 is located at any position between the nickel anchoring structures 2 at both ends. It can be arranged according to the actual output deformation requirements of the micro-artificial muscle driver. If it is at the midpoint position, it is symmetrically distributed. At this time, the output of the micro-artificial muscle driver at both ends is also symmetrical. The nickel anchoring structure 2 has two functions: one is to fix the SMA wire 3 and the elastic substrate 1, and the other is to form a conductive path with the contacted SMA wire 3.

[0059] After thermal training, the SMA wire 3 can achieve bidirectional deformation, shrink in length when heated, and return to its initial state when cooled. The specific number of SMA wires 3 can be determined according to the mechanical characteristics of the driver output. The SMA wire 3 will undergo phase change due to the geothermal effect of electric current, thereby causing contraction deformation and shortening in length. When the power is off, the SMA wire 3 will cool down and return to its initial state.

[0060] The photolithographic array structure 4 is formed by solidifying photoresist and is evenly distributed on the upper and lower layers of the elastic substrate 1, thereby embedding the SMA wire 3 inside the micro-artificial muscle actuator. When the SMA wire 3 is energized and contracts to generate strain, the elastic substrate 1 will bend. Since the photolithographic array structure 4 constrains the SMA wire 3 on the elastic substrate 1, its distance from the elastic substrate 1 will remain consistent, which will increase the bending effect of the elastic substrate 1.

[0061] The PDMS flexible layer 5 is cast in the gaps of the mesh structure to increase the structural strength and elasticity of the entire micro artificial muscle actuator.

[0062] A method for preparing a micro artificial muscle actuator capable of bidirectional bending and deformation comprises the following steps:

[0063] S1, preparing an elastic substrate 1;

[0064] S1-1, the carbon fiber layer 101 and the glass fiber structure 102 are formed by curing a single carbon fiber prepreg and a single glass fiber prepreg, and the single carbon fiber prepreg and the single glass fiber prepreg are processed into a plate shape by an ultraviolet laser cutting machine, such as Figure 2 and 3 As shown, through appropriate tooling alignment, the single carbon fiber prepreg is symmetrically arranged on the upper and lower sides of the single glass fiber prepreg to form the original design structure;

[0065] S1-2, put it into a high-pressure and high-temperature box, set the pressure, temperature, and curing time. In this embodiment, the pressure is set to 1000KG / m 2 , temperature 120 ℃, curing for 2 hours, after the high temperature and high pressure treatment, the single carbon fiber prepreg and the single glass fiber prepreg are cured into a carbon fiber layer 101 and a glass fiber structure 102, and the carbon fiber layer 101 and the glass fiber structure 102 are tightly cured and bonded to form an elastic substrate 1, such as Figure 4 and 5 As shown;

[0066] S2, preparing SMA wire 3;

[0067] S2-1. Conduct a tensile test on the experimental SMA wire at room temperature (25°C) to determine the stress magnitude of the thermal cycle during the constant load training process. Obtain a stress-strain diagram through the experiment to determine the stress magnitude P at which the experimental SMA wire undergoes a complete martensitic phase transformation.

[0068] A new SMA wire 3 of the same model as the experimental SMA wire was taken, and stress P was applied to the SMA wire 3 and thermal training was performed. The SMA wire 3 was heated to shrink and then cooled to restore its original shape. The heating and cooling process was repeated multiple times. In this embodiment, the cycle was repeated 1000 times. After 1000 cycles, the thermal strain of the SMA wire 3 was about 5%, and the phase change activation current of the trained SMA wire 3 started from about 500mA and ended at 800mA.

[0069] The substrate is cleaned with an alcohol brush, impurities are cut with a laser, rinsed with pure water, blown clean with high-purity nitrogen, and then immersed in an acetone solution. It is then placed in an ultrasonic cleaner for vibration washing. In this embodiment, the vibration washing is performed for 5 minutes. After being taken out, it is rinsed with anhydrous ethanol and pure water. The properties of acetone being soluble in ethanol and ethanol being soluble in water are utilized to achieve the purpose of thorough cleaning. It is then blown clean with high-purity nitrogen to obtain a substrate with a clean surface, laying the foundation for uniform and tight coating of photoresist.

[0070] S2-2. Sputter a TiW layer 103 and a Ni layer 104 next to the glass fiber structure 102. TiW alloy has strong adhesion to many common substrate materials, such as silicon and silicon oxide. This allows other thin films to be successfully deposited on it without peeling or cracking. These properties make TiW alloy an ideal adhesion layer. On this basis, a 300nm Ni layer 104 is sputtered to prepare for the subsequent electroplating of anchor nickel.

[0071] S2-3, the SMA wires 3 prepared above are evenly and symmetrically arranged on the upper and lower sides of the elastic base 1, and fixed by a temporary support structure 301, as shown in FIG. Figure 6 and 7 As shown, the SMA wire 3 is kept at a certain distance from the elastic substrate 1. The distance can be within tens of microns. Different values ​​will affect the output deformation angle of the micro-artificial muscle actuator. The larger the value, the smaller the output deformation angle of the micro-artificial muscle actuator. The specific relationship is:

[0072] h·θ=ε·l;

[0073] Wherein, h is the height of the SMA wire 3 from the neutral line of the elastic substrate 1, θ is the angle between the end of the micro artificial muscle actuator and the position before deformation, ε is the shrinkage rate of the SMA wire 3, and l is the original length of the SMA wire 3.

[0074] S3, preparing nickel anchoring structure 2;

[0075] S3-1, take a certain amount of photoresist, which can be easily removed after curing, and put it into a vacuum box to evacuate the air to eliminate bubbles in the photoresist. Pour the vacuumed photoresist onto the substrate obtained in step S2;

[0076] S3-2. According to the characteristics of the photoresist, consult the corresponding photoresist technical documents, set the speed and spin coating time of the spin coater, use the spin coater to spin coat the photoresist on the substrate to obtain a photoresist layer of a certain thickness, place the substrate coated with the photoresist layer of a certain thickness on a heating plate and bake it in sequence at 65°C for 1 minute, 80°C for 2 minutes, and 65°C for 1 minute. The temperature of the heating plate is lower than the phase transition temperature of the SMA wire 3.

[0077] Repeat the spin coating of photoresist and the hot plate baking until the photoresist is evenly coated on the substrate by the coating machine to obtain the first photoresist layer 201. Figure 8 and 9 As shown, after natural cooling, a maskless photolithography machine is used for exposure to obtain an exposure pattern;

[0078] S3-3. Draw an exposure pattern using AutoCAD and copy it into a maskless lithography machine. Based on the photoresist model and lithography machine used, consult the corresponding photoresist technical documentation to calculate the exposure dose. After multiple experiments, transfer the drawn exposure pattern to a substrate coated with photoresist at an appropriate exposure dose to obtain an exposed substrate.

[0079] S3-4, placing the exposed substrate on a hot plate and baking in sequence at 65°C for 1 minute, 80°C for 2 minutes, and 65°C for 1 minute, and then naturally cooling the substrate and developing it in a photoresist developer. After developing for 30 seconds, take it out and rinse it with pure water. If there are areas where the development is not uniform and the photoresist remains, use a micro syringe to draw the developer and gently spray it, then rinse it with pure water. Place the rinsed substrate on a hot plate and bake it at 85°C for 5 minutes. If negative photolithography is used, the photoresist in the exposed part will be cross-linked and become insoluble and will not be washed away by the developer. If positive photolithography is used, on the contrary, the photoresist in the exposed part will be destroyed and thus washed away by the developer.

[0080] The cured photoresist 202 remains on the substrate, such as Figure 10 and 11 As shown;

[0081] S3-5, immersing the substrate in a mixed solution of HF and H2O, with a mixing ratio of HF:H2O=1:10, to remove the oxide layer of the SMA wire 3 and the oxide layer of the Ni layer 104;

[0082] S3-6, electroplating nickel in the area where the photoresist falls off to form a nickel anchoring structure 2, such as Figure 12 and 13 As shown, the plating conditions are selected according to the guidelines provided by the manufacturer and the processing data provided in the literature, and the remaining cured photoresist 202 is stripped, as shown in FIG. Figure 14 and 15 As shown;

[0083] S4, preparing a photolithographic array structure 4;

[0084] S4-1, take the photoresist and put it into a vacuum box to evacuate, pour the vacuumized photoresist on the substrate obtained in step S3, use a spin coater to spin-coat the photoresist to obtain a second photoresist layer 203, such as Figure 16 and 17 As shown;

[0085] S4-2, repeating steps S3-2 to S3-4, forming a photolithographic array structure 4 on the substrate, such as Figure 18 and 19 As shown, at this time, the SMA wire 3, the nickel anchoring structure 2 and the photolithographic array structure 4 form a mesh structure;

[0086] S5. Use a glue spreader to evenly apply PDMS on the substrate so that the PDMS fills the gaps in the mesh structure. Figure 20 and 21 As shown, a PDMS flexible layer 5 is obtained;

[0087] S6. Remove the temporary support structure 301 of the substrate and cut off the excess SMA wires 3 at both ends to obtain a micro artificial muscle actuator capable of bidirectional bending and deformation.

[0088] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

Claims

1. A micro artificial muscle actuator capable of bidirectional bending and deformation, characterized in that: The invention comprises an elastic substrate (1), a nickel anchoring structure (2), an SMA wire (3), a photolithographic array structure (4) and a PDMS flexible layer (5), wherein the nickel anchoring structure (2), the SMA wire (3) and the photolithographic array structure (4) are symmetrically arranged on the upper and lower sides of the elastic substrate (1), the photolithographic array structure (4) is in multiple columns, the SMA wire (3) is in multiple rows and vertically passes through the photolithographic array structure (4) to form a mesh structure with the SMA wire (3), the nickel anchoring structure (2) is located at both ends of the SMA wire (3), the PDMS flexible layer (5) is cast in the gap of the mesh structure, and the elastic substrate (1) comprises a carbon fiber layer (101) and a glass fiber structure (102), and the carbon fiber layer (101) is in the shape of a plate with a hollow structure.

2. The micro artificial muscle actuator capable of bidirectional bending and deformation according to claim 1, characterized in that: The glass fiber structures (102) are symmetrically arranged on the upper and lower sides of the carbon fiber layer (101), and the glass fiber structures (102) and the nickel anchoring structures (2) are the same in number and have corresponding positions.

3. The micro artificial muscle actuator capable of bidirectional bending and deformation according to claim 1, characterized in that: A nickel anchoring structure (2) is also provided at each midpoint of the upper and lower sides of the elastic base (1).

4. A method for preparing a micro artificial muscle actuator capable of bidirectional bending and deformation, characterized in that: The following steps are involved: S1. preparing an elastic substrate (1); S1-1, using an ultraviolet laser cutting machine to process the carbon fiber layer (101) and the glass fiber structure (102) into a plate shape, wherein the glass fiber structure (102) is symmetrically arranged on the upper and lower sides of the carbon fiber layer (101); S1-2, subjecting the carbon fiber layer (101) and the glass fiber structure (102) to high temperature and high pressure treatment, setting the pressure to 1000KG / m 2 , the temperature is 120°C, and the curing is performed for 2 hours. After the high temperature and high pressure treatment, the carbon fiber layer (101) and the glass fiber structure (102) are tightly cured and bonded to form an elastic substrate (1); S2, preparing SMA wire (3); S2-1. At room temperature, a tensile test is performed on the SMA wire (3) to determine the stress P at which the SMA wire (3) undergoes a complete martensitic phase transformation. The SMA wire (3) is loaded with the stress P and subjected to thermal training. The SMA wire (3) is heated by electricity to shrink it, and then cooled to restore it to its original shape, and the heating and cooling process is repeated multiple times. S2-2, sputtering a TiW layer (103) and a Ni layer (104) next to the glass fiber structure (102); S2-3, symmetrically placing the SMA wire (3) prepared above on the upper and lower sides of the elastic base (1), and fixing them via a temporary support structure (301), so that the SMA wire (3) and the elastic base (1) maintain a certain distance; S3, preparing nickel anchoring structure (2); S3-1, take the photoresist and put it into a vacuum box to evacuate the vacuum, and pour the vacuumized photoresist on the substrate obtained in step S2; S3-2, using a coating machine to coat the substrate with photoresist to obtain a first photoresist layer (201), placing the substrate coated with photoresist on a heating plate for baking, wherein the temperature of the heating plate is lower than the phase transition temperature of the SMA wire (3), and after natural cooling, using a maskless photolithography machine for exposure to obtain an exposure pattern; S3-3, drawing an exposure pattern and copying it into a maskless photolithography machine, and after specifying an exposure dose, transferring the drawn exposure pattern onto a substrate coated with a photoresist to obtain an exposed substrate; S3-4, placing the exposed substrate on a heating plate for baking, and after cooling, placing it in a photoresist developer for development, and taking it out after a certain period of development, leaving the solidified photoresist (202) on the substrate; S3-5, immersing the substrate in a mixed solution of HF and H2O to remove the oxide layer of the SMA wire (3) and the oxide layer of the Ni layer (104); S3-6, electroplating nickel in the area where the photoresist has fallen off to form a nickel anchoring structure (2), and peeling off the remaining solidified photoresist (202); S4, preparing a photolithographic array structure (4); S4-1, taking the photoresist and putting it into a vacuum box to evacuate, pouring the vacuumed photoresist onto the substrate obtained in step S3, and using a spin coater to spin-coat the photoresist to obtain a second photoresist layer (203); S4-2, repeating steps S3-2 to S3-4 to form a photolithographic array structure (4) on the substrate, wherein the SMA wire (3), the nickel anchoring structure (2) and the photolithographic array structure (4) form a network structure; S5. Use a coating machine to spin-coat PDMS on the substrate so that the PDMS fills the gaps in the mesh structure to obtain a PDMS flexible layer (5); S6. Remove the temporary support structure (301) of the substrate and cut off the excess SMA wires (3) at both ends to obtain a micro artificial muscle actuator capable of bidirectional bending and deformation.

5. The method for preparing a micro artificial muscle actuator capable of bidirectional bending and deformation according to claim 4, characterized in that: In step S2-1, the substrate is cleaned with an alcohol brush, impurities are cut with a laser, rinsed with pure water, blown clean with high-purity nitrogen, and then immersed in an acetone solution. It is then placed in an ultrasonic cleaning machine for vibration washing. After being taken out, it is rinsed with anhydrous ethanol, rinsed with pure water, and then blown clean with high-purity nitrogen to obtain a substrate with a clean surface.

6. The method for preparing the bidirectionally bendable micro artificial muscle actuator according to claim 4, wherein: In the step S3-2, the rotation speed of the coating machine is first set according to the photoresist technical document to obtain a photoresist layer of a certain thickness, which is then placed on a heating plate and baked at 65°C for 1 minute, 80°C for 2 minutes, and 65°C for 1 minute. The photoresist is spin-coated again and baked repeatedly until the photoresist evenly coats the substrate, thereby obtaining a first photoresist layer (201).

7. The method for preparing the bidirectionally bendable micro-artificial muscle actuator according to claim 4, wherein: In step S3-4, if there are areas where the development is not uniform and the photoresist remains, a developer is drawn up with a syringe and sprayed, and then rinsed with pure water. The rinsed substrate is placed on a hot plate and baked at 85° C. for 5 minutes.

8. The method for preparing a micro artificial muscle actuator capable of bidirectional bending and deformation according to claim 4, characterized in that: In the step S2-1, the thermal training cycle is a heating and cooling process 1000 times, and in the step S3-5, the mixing ratio of the HF and H2O mixed solution is 1:10.

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