Preparation method of flexible driver based on force-deformation cooperative regulation and control

Abstract

The invention discloses a preparation method of a flexible driver based on force-deformation cooperative regulation and control, and belongs to the technical field of flexible robots with high output force and large deformation performance. Carbon nanotubes are directionally arranged in a polymer along the direction of an electric field by utilizing an electric field arrangement technology; the directionally arranged carbon nanotubes not only can improve the electrostrictive strain of the composite material, but also can improve the overall rigidity of the composite material, so that the force-deformation synergistic flexible driver simultaneously realizes large deformation and high output force in a low driving electric field, and the problem that the polymer composite material is soft but not rigid for a long time is solved; on the basis, a polymer composite material membrane serving as a force-deformation synergistic flexible driver is adhered to a supporting body to obtain a climbing robot, and the climbing robot realizes a climbing function on a large-gradient plane; the method is simple to operate and easy to implement, provides a new idea for preparing a high-performance flexible climbing robot, and has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible actuators, and in particular relates to a method for preparing a flexible actuator based on force-deformation coordinated regulation. Background Art

[0002] As the core component of a flexible robot, the actuator needs to produce enough deformation to complete the required action and needs to have enough output force to complete the required action, such as grasping, supporting tools, transporting objects, etc. However, due to the conflict between large strain and high stiffness, it is a huge challenge to realize actuator materials with both large deformation and high output force. Traditional actuator materials include ferroelectric ceramics, which can produce sufficient output force due to their high stiffness, but their small deformation severely limits their application in flexible robots.

[0003] Electroactive polymers, including typical polyvinylidene fluoride (PVDF)-based ferroelectric polymers and dielectric elastomers, have the advantages of good flexibility, ultra-large electric field response strain, low density, simple production process, and low cost, and have great application prospects in biomedicine, aerospace, bionics and other fields. However, the driving electric field of electroactive polymers is relatively high, which is not conducive to their long-term reliability and safety during use. Although some studies (Chen, X. et al. Giantelectrostriction enabled by defect-induced critical phenomena in relaxorferroelectric polymers. Macromolecules 56, 690-696 (2023); Gong, H. et al. Tuning the ferroelectric phase transition of P (VDF-TrFE) through a simple approach of modification by introducing double bonds. ACS Omega 7, 42949–42959 (2022).) have achieved materials with large strains under low driving electric fields, there is still a problem of low output force caused by extremely low modulus. Therefore, in order to expand its application range, electroactive polymer actuators with large deformation must overcome their low output force limitation; however, the generation of high output force often leads to a reduction in strain. Therefore, to date, there is no effective method to achieve both large deformation and high output force of electroactive polymer actuators. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing a flexible actuator based on force-deformation synergistic regulation, by arranging the nanoparticles in the electroactive polymer through an external field, and synchronously realizing the force-deformation synergistic enhancement effect of the flexible actuator through microstructure design, while achieving large deformation and high output force of the electroactive polymer actuator.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a flexible actuator based on force-deformation coordinated regulation, comprising:

[0007] uniformly growing an aluminum oxide insulating layer on the surface of the carbon nanotube; uniformly dispersing the carbon nanotubes with the aluminum oxide insulating layer in a polymer solution to obtain a carbon nanotube-polymer dispersion;

[0008] Applying an electric field, under the action of the electric field, the carbon nanotubes in the carbon nanotube-polymer dispersion form a directional arrangement in the dispersion along the direction of the electric field application, and after drying, a polymer composite film with directional arrangement of carbon nanotubes is obtained, that is, a force-deformation coordinated flexible actuator is obtained;

[0009] Wherein, the concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 0.5% to 1.1%;

[0010] The solute of the polymer solution is polyvinylidene fluoride and its copolymers, including polyvinylidene fluoride (PVDF), polyvinyl fluoride-trifluoroethylene (P(VDF-TrFE)), polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene (P(VDF-TrFE-CFE)) and polyvinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene (P(VDF-TrFE-CTFE)), and the solvent is N,N-dimethylformamide.

[0011] The thickness of the aluminum oxide insulating layer is 5-10 nm.

[0012] The preparation method of the carbon nanotube-polymer dispersion is as follows: uniformly dispersing the carbon nanotubes grown with an aluminum oxide insulating layer in a polymer solution, and ultrasonically oscillating for 2 to 5 hours in an ice water bath to obtain the carbon nanotube-polymer dispersion.

[0013] The specific operation of forming the directional arrangement of carbon nanotubes is: at a temperature of 60-70°C, an electric field parallel to the preset arrangement direction is applied, and the electric field strength is 100-400V pp / mm, lasting for 20 to 40 minutes.

[0014] The concentration of the polyvinylidene fluoride and its copolymer is 8% to 12%.

[0015] A force-deformation coordinated flexible actuator is prepared based on the method described.

[0016] A climbing robot is provided, in which a force-deformation coordinated flexible actuator is assembled as the driving force of the climbing robot.

[0017] The main structural material of the climbing robot is a flexible polymer film, including polyimide (PI), polyethylene terephthalate (PET) and polymethyl methacrylate (PMMA).

[0018] The assembly method of the climbing robot comprises: taking a polymer composite film with a length of 2-7 cm, a width of 1-4 cm, and a thickness of 18-22 μm as a force-deformation coordinated flexible actuator, sputtering 100 nm thick silver electrodes on both sides thereof, and leading out the electrodes through silver tape; and then attaching the polymer composite film to a support film with a length of 4-6 cm, a width of 2-7 cm, and a thickness of 0.5-2.5 mm through double-sided tape.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention utilizes electric field alignment technology to align carbon nanotubes in a polymer dispersion along the direction of the electric field. The aligned carbon nanotubes can increase the electrostrain of the polymer composite material under a low driving electric field.

[0021] (2) The present invention utilizes electric field alignment technology to orient carbon nanotubes in the polymer dispersion along the direction of the electric field. The orientated carbon nanotubes can enhance the overall stiffness of the polymer composite material, thereby enabling the polymer composite actuator to achieve high output force under a low driving electric field.

[0022] (3) The force-deformation coordinated flexible actuator of the present invention achieves large deformation and high output force simultaneously, and is successfully applied to a climbing robot, realizing its climbing function on steep slopes (with a slope of up to 52°).

[0023] In summary, the present invention regulates the arrangement of carbon nanotubes in the composite material so that the force-deformation coordinated flexible actuator can simultaneously obtain large deformation and high output force under a relatively low electric field, thus solving the long-standing problem that the polymer composite actuator is soft but not rigid; thanks to the high output force of the force-deformation coordinated flexible actuator, the climbing robot successfully realizes the crawling function on a plane with a large slope. The present invention is simple to operate and easy to implement, and provides a new idea for preparing high-performance flexible actuators and expanding their practical applications in flexible robots, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1Schematic diagram of the preparation of a composite material film containing aligned nanoparticles in the embodiment;

[0025] Figure 2 The electro-induced strain of the polymer composite material in Example 4 and the comparative example under different electric fields;

[0026] Figure 3 is the output force of the polymer composite material in Example 4 and the comparative example under different electric fields;

[0027] Figure 4 The climbing function of the climbing robot on a steep slope (52°) in Example 4 and the comparative example. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] Example 1: Reference Figure 1 , a method for preparing a flexible actuator based on force-deformation coordinated regulation, comprising:

[0031] A uniform and dense aluminum oxide insulating layer with a thickness of 10 nm is grown on the surface of the carbon nanotubes by using atomic layer deposition technology; a carbon nanotube-polymer dispersion is prepared, and the concentration of the carbon nanotubes is 0.5%. Specifically, the carbon nanotubes deposited with the aluminum oxide insulating layer are dispersed in a P (VDF-TrFE-CTFE) polymer solution with a concentration of 12%, and a uniformly dispersed suspension is obtained after ultrasonic oscillation for 2 hours under the condition of an ice water bath;

[0032] The dispersion containing carbon nanotubes was evenly coated on a glass plate by scraping at 60°C and 100V. pp The carbon nanotubes in the dispersion are oriented under an electric field condition of / mm for 40 minutes, and are placed in an oven at 130°C for 2 hours to obtain a polymer composite film with oriented carbon nanotubes, that is, a force-deformation coordinated flexible actuator.

[0033] A climbing robot is assembled with a force-deformation coordinated flexible actuator as the driving force of the climbing robot; the assembling method comprises: taking a polymer composite film with a length of 4 cm, a width of 2 cm and a thickness of 18 μm as the force-deformation coordinated flexible actuator, sputtering 100 nm thick silver electrodes on both sides thereof, and leading out the electrodes through silver tape; then attaching the polymer composite film to a support film with a length of 6 cm, a width of 4 cm and a thickness of 0.5 mm through double-sided tape, leading it out through silver tape so as to apply a driving electric field, and attaching it to the support through double-sided tape to assemble it into a climbing robot with a simple structure.

[0034] Example 2: The concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 1.1%, and the remaining operations are the same as in Example 1.

[0035] Example 3: The thickness of the aluminum oxide insulating layer on the surface of the carbon nanotubes is 7.5 nm, and the concentration of the carbon nanotubes in the carbon nanotube-polymer dispersion is 1.1%; ultrasonic oscillation is performed in an ice water bath for 4 hours; at a temperature of 70°C, the electric field for the alignment is 300V pp / mm; the climbing robot polymer composite film has a length of 7 cm, a width of 4 cm and a thickness of 22 microns, and the support film has a length of 6 cm, a width of 7 cm and a thickness of 2.5 mm; the rest of the operations are the same as in Example 1.

[0036] Example 4: The thickness of the aluminum oxide insulating layer on the surface of the carbon nanotubes is 5 nm, and the concentration of the carbon nanotubes in the carbon nanotube-polymer dispersion is 1.1%; ultrasonic oscillation is performed in an ice water bath for 5 hours; at a temperature of 65°C, the electric field for directional alignment is 300V pp / mm, the climbing robot polymer composite film has a length of 2 cm, a width of 1 cm, and a thickness of 20 μm, and the support film has a length of 4 cm, a width of 2 cm, and a thickness of 1 mm; the rest of the operations are the same as in Example 1.

[0037] Example 5: The thickness of the aluminum oxide insulating layer on the surface of the carbon nanotube is 7.5 nm, the concentration of the carbon nanotube in the carbon nanotube-polymer dispersion is 0.8%, and the electric field for directional alignment is 400 V pp / mm, the duration is 20min, and the rest of the operations are the same as in Example 1.

[0038] Example 6: The thickness of the aluminum oxide insulating layer on the surface of the carbon nanotube is 5 nm, the concentration of the carbon nanotube in the carbon nanotube-polymer dispersion is 0.8%, and the electric field for directional alignment is 400 V pp / mm, the duration is 20min, and the rest of the operations are the same as those in Example 3.

[0039] Example 7: The thickness of the aluminum oxide insulating layer on the surface of the carbon nanotube is 5 nm, the concentration of the carbon nanotube in the carbon nanotube-polymer dispersion is 0.8%, and the electric field for directional alignment is 400 V pp / mm, the duration is 30min, and the rest of the operations are the same as those in Example 4.

[0040] Example 8: The polymer is PVDF, and the remaining operations are the same as those in Example 3.

[0041] Example 9: The polymer is P(VDF-TrFE), and the remaining operations are the same as those in Example 4.

[0042] Example 10: The polymer is P(VDF-TrFE-CFE), and the remaining operations are the same as those in Example 5.

[0043] Comparative Example 1:

[0044] a. Disperse 1 g of polymer powder (PVDF or P(VDF-TrFE) or P(VDF-TrFE-CFE) or P(VDF-TrFE-CTFE)) in 10 mL of N,N-dimethylformamide and stir for 10 h to obtain a polymer solution;

[0045] b. The polymer solution is evenly coated on a glass plate by a scraping method, dried at 50 to 100° C., and then placed in an oven at 110 to 130° C. for 2 to 4 hours to obtain a polymer composite film;

[0046] c. Silver electrodes with a thickness of about 100 nm were sputtered on both sides of the polymer composite film, and were led out through silver tape to apply a driving electric field. They were attached to a support body through double-sided tape to assemble into a simple climbing robot.

[0047] Reference Figure 2 , Figure 2 The test results of the electrostrain of the polymer composite materials in Example 4 and the comparative example under different electric fields show that the composite material containing transversely arranged carbon nanotubes achieves higher electrostrain under the same electric field. Figure 3 , Figure 3 The output force test results of the polymer composite materials in Example 4 and the comparative example under different electric fields show that the transversely arranged carbon nanotubes greatly increase the output force of the composite membrane actuator and significantly reduce its driving electric field. Figure 4 , Figure 4 The climbing function of the climbing robot on a steep slope (52°) in Example 4 and the comparative example shows that the climbing robot can achieve the climbing function on a steep slope with a slope of up to 52°.

[0048] It can be seen from the embodiments and comparative examples that the comparative example cannot complete the climbing function on the steep slope due to the smaller strain and output force. The embodiment uses the method of electric field arrangement to obtain a polymer film driver with large strain and large output force, and successfully realizes the climbing function of the climbing robot on the steep slope. The dispersion of the polymer is mainly achieved by stirring and ultrasonic oscillation, the preparation of the polymer composite film is mainly prepared by the method of scraping the film, the directional arrangement of the carbon nanotubes in the composite material is mainly achieved by the regulation of the electric field after the scraping film, and the arrangement of the internal carbon nanotubes increases the output force of the composite material while increasing the strain of the composite material, and finally successfully uses the force-deformation coordinated flexible driver for a flexible climbing robot with a simple structure. The advantage of the method of the present invention is that a flexible driver with force-deformation coordination having large deformation and high output force can be obtained, thereby obtaining a flexible climbing robot with excellent performance, wherein the use of the scraping film method is also conducive to the industrial production of the film, the whole process is simple and easy, and the assembled climbing robot has a simple structure, which provides a new idea for preparing a flexible bionic robot adapted to different ground environments, and has good application prospects and economic benefits.

[0049] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a flexible actuator based on force-deformation coordinated regulation, characterized in that: Uniformly growing an aluminum oxide insulating layer on the surface of the carbon nanotubes; uniformly dispersing carbon nanotubes grown with an aluminum oxide insulating layer in a polymer solution to obtain a carbon nanotube-polymer dispersion; An electric field is applied. Under the action of the electric field, the carbon nanotubes in the carbon nanotube-polymer dispersion form a directional arrangement in the dispersion along the direction of the electric field application. After drying, a polymer composite film with directional arrangement of carbon nanotubes is obtained, that is, a flexible actuator with force-deformation synergy is obtained. Wherein, the concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 0.5% to 1.1%; The solute of the polymer solution is polyvinylidene fluoride and its copolymers, including polyvinylidene fluoride (PVDF), polyvinyl fluoride-trifluoroethylene (P(VDF-TrFE)), polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene (P(VDF-TrFE-CFE)) and polyvinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene (P(VDF-TrFE-CTFE)), and the solvent is N,N-dimethylformamide.

2. The method according to claim 1, characterized in that The thickness of the aluminum oxide insulating layer is 5 to 10 nm.

3. The method according to claim 1, characterized in that The preparation method of the carbon nanotube-polymer dispersion is as follows: uniformly dispersing the carbon nanotubes grown with an aluminum oxide insulating layer in a polymer solution, and ultrasonically oscillating for 2 to 5 hours in an ice water bath to obtain the carbon nanotube-polymer dispersion.

4. The method according to claim 1, characterized in that: The specific operation of forming the directional arrangement of carbon nanotubes is: at a temperature of 60-70°C, an electric field parallel to the preset arrangement direction is applied, and the electric field strength is 100-400V pp / mm, lasting 20 to 40 minutes.

5. The method according to claim 1, characterized in that The concentration of polyvinylidene fluoride and its copolymer is 8% to 12%.

6. A force-deformation coordinated flexible actuator, characterized in that: Prepared by the method according to any one of claims 1 to 5.

7. A climbing robot, characterized in that: The force-deformation coordinated flexible actuator described in claim 6 is assembled as a drive for a climbing robot.

8. A climbing robot according to claim 7, characterized in that: The main structural material of the climbing robot is a flexible polymer film, including polyimide (PI), polyethylene terephthalate (PET) and polymethyl methacrylate (PMMA).

9. The method for assembling a hill-climbing robot according to claim 7, characterized in that: A polymer composite film with a length of 2-7 cm, a width of 1-4 cm, and a thickness of 18-22 μm as a force-deformation coordinated flexible actuator is taken, 100 nm thick silver electrodes are sputtered on both sides thereof, and the electrodes are led out through silver tape; the polymer composite film is then attached to a support film with a length of 3-6 cm, a width of 2-7 cm, and a thickness of 0.5-2.5 mm through double-sided tape.

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