Gas confined actuated artificial muscle fiber system, applications thereof, and underwater robots

Abstract

This invention provides a gas-confined actuated artificial muscle fiber system, its applications, and underwater robots. The artificial muscle fiber system includes artificial muscle fibers and an electrolyte. The artificial muscle fibers are placed in the electrolyte and include a mandrel and a sheath, twisted and shaped into an overtwisted spiral. The sheath allows the electrolyte to pass through and contact the mandrel. The mandrel acts as an electrode, electrolyzing the electrolyte to form a gas-filled structure, causing radial expansion which is converted into axial driving force. This invention, while ensuring the electrolyte can contact the mandrel (acting as an electrode), prevents the gas generated by electrolysis from dissipating in a short time. Instead, it confines the gas between the sheath and the mandrel within the required driving time window, causing volume expansion. This utilizes the spiral twisting structure to generate axial driving force. Compared to existing actuation methods for artificial structural fibers, the artificial muscle fiber system provided by this invention represents a groundbreaking new actuation method.

Description

Technical Field

[0001] This invention belongs to the field of artificial muscle technology, specifically relating to a gas-confined driven artificial muscle fiber system, its applications, and underwater robots. Background Technology

[0002] Soft robotics has become a transformative technology, enabling adaptive and safe interaction with delicate objects, unstructured environments, and biological tissues. This technology holds immense application potential in fields such as medical implants, wearable devices, and environmental detection. Among these, underwater soft robots that mimic the movement of aquatic animals such as fish, rays, and cephalopods can overcome the limitations of traditional rigid platforms in terms of mobility and stealth, showing broad prospects in scenarios such as ocean exploration, environmental monitoring, and covert operations. However, the development of such systems is often constrained by the level of development of soft actuators—existing actuators struggle to simultaneously meet core requirements such as adaptability to aquatic environments, high power density, miniaturization, and integration.

[0003] The driving technologies for underwater soft robots mainly include pneumatic / hydraulic systems, dielectric elastomer actuators (DEAs), and optical / thermal actuation mechanisms. Despite significant progress in these technologies, prominent shortcomings remain in aquatic applications. For example, pneumatic / hydraulic actuators require large auxiliary pump systems, severely limiting the robot's autonomy and maneuverability; DEAs typically operate at kilovolt levels and are prone to electrical breakdown upon contact with conductive liquids, leading to premature failure during long-term underwater service; while thermal actuation systems suffer from low energy efficiency, slow response speed, and poor penetration in turbid water. Therefore, developing a new paradigm of high-performance soft actuators that can operate stably and efficiently in aquatic environments has become a critical issue urgently needing to be addressed in this field. Electrochemical actuators offer advantages such as simple structure and mild actuation conditions, with carbon nanotube (CNT)-based electrochemical actuators attracting particular attention due to their low operating voltage and high power density. Most reported electrochemical actuators rely on ion intercalation or solvent swelling to achieve volume deformation; these mechanisms not only depend on specific electrolytes but also generally suffer from inherent drawbacks such as slow diffusion kinetics.

[0004] It is worth noting that the electrolysis of water, an electrochemical process that directly generates bubbles, has long been neglected as a mainstream driving mechanism for in-depth research. The main reason is that freely generated bubbles rapidly dissipate into the surrounding environment, failing to produce effective volume deformation. How to effectively utilize electrolyzed bubbles to achieve strong driving force and high controllability remains an unsolved problem. The core bottleneck lies in how to suppress bubble dissipation while ensuring that the electrolytic interface in artificial muscles can contact the electrolyte. Summary of the Invention

[0005] The main objective of this invention is to provide a gas-confined driven artificial muscle fiber system, its applications, and underwater robots, in order to overcome the shortcomings of the prior art.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a gas-confined driven artificial muscle fiber system, which includes artificial muscle fibers and an electrolyte, wherein the artificial muscle fibers are placed in the electrolyte and include a core and a sheath, and are twisted and shaped into an overtwisted spiral state. The sheath is selected from a material with electrolyte-loving properties, allowing the electrolyte to pass through and contact the mandrel. The mandrel is made of a conductive material. When the mandrel acts as an electrode to electrolyze the electrolyte, a gas-filled space is formed between the mandrel and the sheath, causing the artificial muscle fiber to expand radially. This radial expansion is converted into an axial driving force.

[0007] Secondly, the present invention also provides the application of the above-mentioned artificial muscle fiber system in the field of manufacturing soft robots.

[0008] Thirdly, as a specific manifestation of the above application, the present invention also provides an underwater robot. When the underwater robot is in water, the driving structure of the underwater robot includes the above-mentioned artificial muscle fiber system, and the surrounding water is used as an electrolyte to perform the driving.

[0009] Compared with the prior art, the beneficial effects of the present invention include at least the following: The artificial muscle fiber system provided by this invention, through the material design of the sheath layer, ensures that the electrolyte can contact the core shaft, which serves as the electrode, while preventing the gas generated by electrolysis from escaping in a short time. Instead, the gas is confined between the sheath layer and the core shaft within the time window required for driving, causing volume expansion. This allows the spiral twisting structure to generate axial driving force. Compared with the driving methods of existing artificial structural fibers, the artificial muscle fiber system provided by this invention represents a groundbreaking new driving method.

[0010] Compared with existing driving methods such as air pressure driving, light driving, and humidity driving, the driving behavior of the artificial muscle fiber system provided by this invention can be controlled by current, which has higher controllability. Compared with electrothermal driving, it requires lower voltage and does not produce obvious thermal effects during the driving process. It also has better performance underwater, has a wider range of applications, a wider driving environment, and the driving effect can increase linearly with the increase of driving current.

[0011] During the actuation process, the artificial muscle fiber system provided by this invention exhibits rapid actuation characteristics, with a maximum instantaneous actuation speed reaching 20% ​​s in a typical embodiment.-1 The instantaneous velocity is greater than that of other electrochemically driven systems; and compared with most currently reported underwater biomimetic muscle fibers, the artificial muscle fiber system provided by this invention has greater driving performance, and in a typical embodiment, it can generate about 50% contraction under a current stimulation of 0.2 A.

[0012] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the preparation process of the artificial muscle fiber system provided in a typical embodiment of the present invention; Figure 2 This is an optical image of the artificial muscle fiber system at different preparation stages before annealing, provided in a typical embodiment of the present invention. Figure 3 This is an optical image of the artificial muscle fiber system separated from the mold after thermal annealing, provided in a typical embodiment of the present invention. Figure 4 This is a test diagram of the driving performance of the artificial muscle fiber system under different currents provided in a typical embodiment of the present invention; Figure 5 This is a test diagram of the driving performance of the artificial muscle fiber system under different loads provided in a typical embodiment of the present invention; Figure 6 This is a static output force test diagram of an artificial muscle fiber system under different currents provided in a typical embodiment of the present invention; Figure 7 This is a rapid drive quantity test diagram of the artificial muscle fiber system provided in a typical embodiment of the present invention; Figure 8 This is a rapid driving force test diagram of an artificial muscle fiber system provided in a typical embodiment of the present invention; Figure 9 This is a test diagram of the rapid driving capability of the artificial muscle fiber system under different currents provided in a typical embodiment of the present invention; Figure 10This is a schematic diagram of the preparation process of integrated hydrogen evolution confined artificial muscle fibers provided in a typical embodiment of the present invention; Figure 11 This is a schematic diagram of the driving mechanism of the integrated hydrogen evolution confined artificial muscle fiber provided in a typical embodiment of the present invention; Figure 12 This is a test diagram of the driving performance of an integrated hydrogen evolution confined artificial muscle fiber provided in a typical embodiment of the present invention; Figure 13 This is a diagram illustrating the lateral driving process of an artificial muscle bionic fish, provided in a typical embodiment of the present invention. Figure 14 This is a schematic diagram illustrating the directional control of an artificial muscle bionic fish provided in a typical embodiment of the present invention; Figure 15 This is a schematic diagram illustrating the precise control of the movement direction of an underwater biomimetic fish, provided in a typical embodiment of the present invention. Detailed Implementation

[0015] The main drawbacks of existing technologies are: 1) The rigid structure and motion noise of traditional motors and other drive units cannot meet the requirements of soft robots for flexibility and stealth. 2) Pneumatic / hydraulic actuators require a large auxiliary pump system, which severely limits the robot's autonomy and maneuverability. 3) Dielectric elastomer actuators (DEAs) typically operate at kilovolt-level high voltages and are prone to electrical breakdown when in contact with conductive liquids, leading to premature failure during long-term underwater service. 4) Thermal drive systems suffer from low energy efficiency, slow response speed, and poor penetration in turbid water. 5) Electrochemical actuators mostly rely on ion intercalation or solvent swelling to achieve volume deformation. These mechanisms not only depend on specific electrolytes, but some electrolyte solutions (such as organic solutions) are also environmentally corrosive and biotoxic, and generally suffer from inherent defects such as slow diffusion dynamics. 6) Currently, artificial muscles capable of underwater actuation mainly rely on hydrogel materials, resulting in slow actuation speed and low actuation force.

[0016] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0017] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0018] This invention first provides a gas-confined driven artificial muscle fiber system, which includes artificial muscle fibers and an electrolyte. The artificial muscle fibers are placed in the electrolyte and include a mandrel and a sheath, and are twisted and shaped into an overtwisted spiral state. The sheath is selected from a material with electrolyte-friendly properties, allowing the electrolyte to pass through and contact the mandrel. The mandrel is made of a conductive material. When the mandrel acts as an electrode to electrolyze the electrolyte, a gas filling is formed between the mandrel and the sheath, causing the artificial muscle fibers to expand radially. The radial expansion is converted into an axial driving force.

[0019] The key technical means of the artificial muscle fiber system provided by this invention lies in using the sheath as a permeation layer for electrolyte and a current transmission layer (similar to the function of the separator in a lithium battery). In addition, the sheath also serves as a gas confinement structure, preventing gas from escaping in a short time. The volume expansion caused by gas filling enables the artificial muscle to drive.

[0020] This method represents a completely new form of actuation and, compared to existing artificial muscles, boasts advantages such as faster response speed and higher actuation efficiency.

[0021] In a typical embodiment, artificial muscle fibers are typically used as the cathode, and hydrogen is generated through electrolysis to form a gas filling. Based on the same principle, the scope of the present invention is not limited to cathode electrolysis, nor is it limited to the generation of hydrogen. Other methods of generating hydrogen through electrolysis, such as using it as the anode to generate oxygen, or various other gases that can be formed through electrolysis, can achieve the same purpose. As long as the electrolyte can be permeable through a reasonable sheath material design, and the gas can be restricted to a certain extent, the axial drive can be achieved by utilizing the gas volume expansion effect.

[0022] In addition, the electrolyte can be aqueous, and salts can be added to improve conductivity. In typical applications, it can be used for underwater robots in natural water bodies, where impurities can enhance conductivity. Of course, the specific applications are not limited to this. It can be an artificially prepared electrolyte used in industrial settings; or even a liquid adsorbed in a gel can be used as the electrolyte, with the gel completely encapsulating the fiber to form a quasi-solid integrated fiber, and so on.

[0023] In the above driving method, in order for the artificial muscle fibers to retract spontaneously after the current is removed and the electrolysis stops, the gas generated by electrolysis needs to be released.

[0024] To achieve this objective, in some embodiments, the sheath also has gas permeability properties, allowing the gas filler to gradually permeate out from between the mandrel and the sheath.

[0025] Of course, the artificial muscle system provided by this invention preferably adopts the above-described configuration, but it is not limited to this. Even if the generated gas filling is not released through the sheath (the release method can be the diffusion of gas in the sheath, or the presence of tiny pores in the sheath through which gas slowly escapes, or the sheath is a discontinuous wrapping layer with gaps in the overlapping area, through which gas escapes, etc.), but is released through other means such as diffusion along the core-sheath interlayer or by setting tiny gas passages in the core shaft to allow it to overflow at a controllable rate, the same purpose can still be achieved. That is, when the drive is executed, the gas overflow rate is less than or equal to the generation rate so that the gas can be kept filling, and when the current is removed, the overflow rate can ensure that the gas filling is dissipated in time to avoid affecting the next drive. The specific overflow rate design can be adjusted according to the application requirements. For example, in some scenarios where rapid recovery is required, a faster overflow rate is needed. In some scenarios where energy utilization is emphasized, the gas can overflow more slowly to avoid energy dissipation caused by a large amount of gas overflow.

[0026] Regarding the specific materials and structure, in some embodiments, the sheath material includes any one or a combination of two or more of hydrophilic PTFE, ETFE, and Nafion.

[0027] In some embodiments, the thickness of the sheath is 150–250 μm. Generally, the sheath thickness should not be too thick, as this would hinder electrolyte penetration and gas escape. However, if the sheath thickness is too thin, it can easily lead to a decrease in driving force. Therefore, an appropriate sheath thickness should be carefully set during the fabrication process. However, the above thickness range is merely an exemplary range for limited embodiments of the present invention; the appropriate thickness will vary depending on the sheath material, and the final thickness should be determined based on the desired functionality.

[0028] In some embodiments, the artificial muscle fiber system further includes a counter electrode, which forms the anode and cathode with the artificial muscle fiber and is placed together in the electrolyte.

[0029] A preferred embodiment of the present invention also provides an implementation where the counter electrode and the artificial muscle fiber are integrated. In this implementation, no additional counter electrode is required; instead, the integrated fiber assembly is directly placed in the electrolyte (e.g., directly immersed in water) to construct the drive system. That is, in some embodiments, the counter electrode is in the form of a fiber, coiled and wound around the artificial muscle fiber. A typical example can be found in the "integrated hydrogen evolution confinement artificial muscle fiber" and its application provided in the following embodiments.

[0030] In some embodiments, the mandrel comprises, from the inside to the outside, a core and a wrapping layer in the radial direction, wherein the core is made of a polymer material and the wrapping layer is made of a nano-carbon material and / or a metal.

[0031] In some embodiments, the polymeric material includes any one or a combination of two or more of nylon, polyethylene, and polyester.

[0032] In some embodiments, the nanomaterial includes any one or a combination of two of carbon nanotubes and graphene.

[0033] In some embodiments, the metal includes any one or a combination of two of silver and platinum.

[0034] The artificial muscle fiber preparation method provided by the above technical solution can refer to the preparation schemes of various twisted fibers with core-sheath structures in the field. A typical preparation method includes wrapping polymer fibers with narrow strip-shaped nano-carbon material, then wrapping a thin film material as a sheath layer on the outside, and then twisting the three together into a whole fiber by integral twisting. After that, it is wound on a rod-shaped mold and heated and baked to obtain a spiral artificial muscle fiber. Of course, feasible preparation methods are not limited to this. It can be in the form of no polymer core, but use a whole carbon material of appropriate diameter as a core shaft. It can also be that the film wrapping or stacking method is not used, but coating, in-situ growth, deposition and other methods are used to form the wrapping layer or sheath layer, as long as the structural layer with the various functions specified in this invention can be obtained.

[0035] This invention also provides the application of the artificial muscle fiber system provided in any of the above embodiments in the field of manufacturing soft robots.

[0036] This invention also provides an underwater robot. When the underwater robot is in water, its drive structure includes the artificial muscle fiber system provided in any of the above embodiments, and it uses the surrounding water as an electrolyte to perform the drive.

[0037] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0038] Example 1 This embodiment provides a preparation process and performance testing of hydrogen evolution confinement driven artificial muscle fibers, as detailed below.

[0039] 1) Preparation method In this embodiment, the preparation of hydrogen evolution-confined artificial muscle fibers first requires encapsulating nylon fibers with narrow carbon nanotubes. Subsequently, the composite fibers are further encapsulated with a PTFE membrane, specifically a hydrophilic PTFE filter membrane from Daikin Industries. To ensure tight interfacial bonding and structural stability, a twisting process is performed on the composite fibers, ultimately forming a defined three-layer structure with distinct functional regions: a PTFE@CNT@Nylon composite fiber.

[0040] like Figure 1 As shown, the specific preparation steps are as follows: Step 1: Preparation of PTFE@CNT@Nylon composite fibers. 20 cm long CNT narrow strips and Nylon fibers are stacked and wrapped in parallel. Then, two 1 cm wide PTFE strips are wrapped inside and fixed to a motor. The motor provides a stable and controlled processing speed for the torsion process. As the motor rotates, the outer PTFE layer uniformly coats the internal fiber structure, thus forming a PTFE@CNT@Nylon fiber structure. Recorded images of the actual preparation process in this step are shown below. Figure 2 As shown, the analysis results were characterized by optical microscopy. The figure shows that the inner diameter of the composite artificial muscle helical fibers is approximately 550 μm. During the actuation process, the biomimetic muscle fibers expand in volume under the confinement of hydrogen gas generated inside, causing the helices to move closer together and ultimately generating axial contraction.

[0041] Step 2: The fibers are wound around an iron mandrel in the same chiral direction, and both ends are fixed. Then, the fibers and the mold are heated at 150 degrees Celsius for 300 minutes to form a stable helical structure of PTFE@CNT@Nylon artificial muscle fibers. Recorded images of the actual fabrication process of this step are shown below. Figure 3 As shown.

[0042] Step 3: Preparation of hydrogen evolution confinement driven electrolyte. The electrolyte solution is prepared by mixing lithium sulfate (Li2SO4) with an aqueous solution at a ratio of 1 mol L⁻¹.

[0043] Step 4: Construction of the working device. An electrochemical biomimetic muscle fiber working device was constructed using a two-electrode system, in which PTFE@CNT@Nylon helical fibers served as the working electrode, a platinum sheet served as the counter electrode, and the electrolyte was a 1 mol L⁻¹ lithium sulfate aqueous solution.

[0044] Step 5: Preparation of integrated positive and negative electrode artificial muscle fibers. After encapsulating CNTs and Nylon inside with PTFE, a 50 μm thick platinum wire is introduced, and the fiber and platinum wire are stacked and fixed on the motor. As the motor rotates, the platinum wire is evenly wound around the fiber surface. After twisting is completed, the integrated fiber is wound on an iron rod mandrel in the same chiral direction, and both ends are fixed. It is then placed in an oven and heated at 150 ℃ for 300 min to provide the fiber pitch.

[0045] 2) Performance Testing This biomimetic muscle fiber responds to lower electrical currents, such as Figure 4 As shown, the fiber driving quantity was tested under different driving current conditions. When the driving current was less than -0.12 A, the fiber driving quantity remained at approximately 5%. However, when the current was above -0.14 A, the fiber driving quantity increased linearly with the increase of the driving current. When the fiber driving current reached -0.2 A, the fiber driving quantity reached approximately 52%. If the current was further increased, the helical structure of the fiber would be disrupted, resulting in an irreversible decrease in the fiber driving quantity.

[0046] This study investigates the effect of driving load on fiber driving performance. Figure 5 The results show that the fiber's driving force initially increases with increasing load, then gradually decreases. When the fiber is suspended under a low load, the light load prevents the fiber from returning to its pre-driving length, resulting in continuous fiber contraction as driving continues, thus reducing the upper limit of the driving force. During the driving process under low load, the driving force cannot increase further after reaching its upper limit, resulting in a relatively low driving force for the composite fiber at that load. Subsequently, as the fiber's driving load increases, the fiber's recovery length during the recovery phase gradually increases, the upper limit of driving begins to rise, and the overall driving performance of the fiber increases. This phenomenon persists until a driving load of around 6g, where the maximum driving force, approximately 42%, is reached. When the load exceeds 6g, the fiber gradually becomes unable to contract and pull the excessively heavy load, and the fiber is gradually stretched as the load increases during driving, leading to a continuous decrease in the driving force. When the driving load reaches 10g, the driving force is essentially only half that under a 6g load.

[0047] Regarding the effect of driving current on fiber driving force, this can be achieved through... Figure 6The driving force curve of the fiber is generally similar to that of the driving amount curve, but with some minor differences. As the data increases over time, the slope of the driving force curve remains relatively constant, while the driving amount curve shows a gradual increase in slope. Furthermore, the driving force is not significantly different above -0.16A, but decreases further with decreasing current. In contrast, the driving amount exhibits a gradient, with a significant decrease in driving amount for each slight reduction in current.

[0048] During testing of the hydrogen evolution confinement driven fiber, it was found that after several sets of training drives, a rapid drive of approximately 4 seconds, with a drive amount of about 15%, would occur at the beginning of the drive. Subsequent studies investigated the instantaneous driving force of the fiber, such as... Figure 7 and Figure 8 As shown.

[0049] During the testing of rapid fiber actuation, it was found that the actuation amount of the fiber was only related to the suspended load and the charging current. When the fiber load was small, the instantaneous actuation amount was relatively large, but the recovery speed increased significantly. Conversely, if the load was too heavy, the fiber's recovery speed improved considerably, but the instantaneous actuation amount decreased to some extent. The influence of the driving current on the instantaneous actuation performance of the fiber was then investigated. Figure 9 It was observed that when the fiber's driving current was above -0.12A, the instantaneous driving amount of the fiber remained stable at around 10%. If the driving current was further reduced, the instantaneous driving amount began to decrease. Furthermore, when the fiber's driving current exceeded -0.12A, a step-like phenomenon appeared during the fiber's recovery process, which was not observed at low currents. Currently, the main hypothesis regarding the fiber's instantaneous driving is that it is due to the fiber's internal structure. Because some hydrogen bubbles remain inside the fiber during the driving process, once the fiber is charged, these bubbles begin to form, causing the fiber to reflexively contract. Considering all usage conditions, the final test conditions were determined to be: applying current at -0.2A for 2 seconds, allowing the current to stabilize at 0 for 28 seconds to recover elongation, with a load of 6g. Under these test conditions, the fiber could achieve a stable driving amount of 12%.

[0050] Example 2 For the hydrogen evolution confinement artificial muscle composite fiber provided in Example 1, one problem has consistently hindered its practical application: the placement of the counter electrode in the electrochemical system. In the experimental environment of Example 1, there was sufficient space to place the platinum counter electrode, but for applications with more complex structures, the counter electrode easily obstructs the flexible movement of the model and the placement of the fiber. To solve this problem, this example develops an integrated artificial muscle composite fiber in which two electrodes are loaded onto the same fiber.

[0051] Its preparation process is as follows Figure 10 As shown, the driving principle is as follows Figure 11 As shown, after encapsulating CNTs and Nylon within PTFE, a 50μm thick platinum wire is introduced, and the fiber and platinum wire are stacked and fixed onto a motor. As the motor rotates, the platinum wire is evenly wound around the fiber surface. After twisting is complete, the integrated fiber is wound onto an iron mandrel in the same chiral direction, and both ends are fixed. It is then placed in an oven at 150℃ for 300 min to provide the fiber pitch. After heating, an integrated hydrogen evolution confinement composite artificial muscle fiber is obtained. During the hydrogen evolution confinement driven test, the platinum wire serves as the counter electrode of the electrochemical system, while the PTFE@CNT@Nylon artificial muscle fiber serves as the working electrode.

[0052] See Figure 12 and Figure 13 As shown, the driving performance of the fiber was analyzed. Under the test conditions of a 4 g load and a driving time of 120 s, the effect of the driving current on the fiber driving behavior was investigated. The driving amount of the fiber increased rapidly with the increase of the driving current. At a driving current of -150 mA, the driving amount could reach 26.6%, and the maximum driving rate could reach 20.04%·s. -1 .

[0053] Example 3 This embodiment illustrates the application of the hydrogen evolution-confined artificial muscle fibers provided in Embodiment 1, such as... Figure 14 As shown, two sets of fibers are fixed to the inside of the fish on both sides, serving as working electrodes for cyclic oscillation. A platinum wire is located at the center, acting as the counter electrode for the reaction. When a leftward oscillation is needed, the fibers on the left are charged, causing them to contract and pull the left side of the fish's tail. This enables the bionic fish to perform a leftward tail sway. Similarly, a similar structure is designed for the rightward tail sway, charging the fibers on the right side, causing them to contract and pull the right side of the fish's tail, enabling the bionic fish to perform a rightward tail sway.

[0054] Based on this, see Figure 15 As shown, this fiber successfully enabled precise control of the movement direction of the underwater bionic fish. With the bionic fish swimming vertically forward, by stimulating the fibers inside the bionic fish, it was successfully made to rotate in a certain direction.

[0055] The above embodiments developed a hydrogen evolution bubble confinement strategy, utilizing bubbles generated by water electrolysis as a power source to successfully convert the electrolyzed hydrogen into a powerful and highly controllable mechanical drive. A gas confinement structure was designed, consisting of a multi-material core-sheath spiral fiber composed of a nylon core layer, a carbon nanotube electrode layer, and an outer polytetrafluoroethylene (PTFE) gas-confining sheath layer. When a negative voltage is applied in an aqueous electrolyte, hydrogen bubbles generated at the carbon nanotube interface are captured by the PTFE sheath layer, causing rapid pressure accumulation and volume expansion within the fiber; this expansion effect is efficiently converted into contraction motion through the fiber's spiral structure. An integrated dual-electrode fiber structure was designed. By co-twisting the core-sheath fiber with platinum wire, an integrated dual-electrode composite fiber actuator was developed, integrating the two electrodes into a single fiber, significantly improving the system's simplicity and adaptability.

[0056] The above-mentioned hydrogen evolution bubble confinement strategy successfully converts the hydrogen generated by electrolysis into a powerful and highly controllable mechanical drive. A multi-material core-sheath spiral fiber was designed, consisting of a nylon core layer, a carbon nanotube electrode layer, and an outer polytetrafluoroethylene (PTFE) gas-limiting sheath layer. When a negative voltage is applied in an aqueous electrolyte, hydrogen bubbles generated at the carbon nanotube interface are captured by the PTFE sheath, causing rapid pressure buildup and volume expansion within the fiber. This expansion effect is efficiently converted into contraction motion through the fiber's spiral structure. This driving mechanism achieves excellent contraction stroke and rate. Furthermore, by co-twisting the core-sheath fiber with platinum wire, an integrated dual-electrode composite fiber actuator was developed, integrating both electrodes into a single fiber, significantly improving the system's simplicity and adaptability. This fiber was integrated as an artificial muscle into a biomimetic robotic fish, enabling controllable tail fin movement through simple electrical signal control, allowing the robotic fish to swim forward and flexibly avoid obstacles underwater. This bubble muscle concept will open up new design avenues for next-generation autonomous underwater robots and liquid environment software systems.

[0057] Example 4 This embodiment provides a gas-confined artificial muscle fiber system of different materials, and the specific preparation process is shown below.

[0058] Step 1: Preparation of PTFE@silver-plated Nylon composite fibers. Two 1cm wide strips of PTFE are used to wrap a 20cm long silver-plated Nylon fiber and fixed to a motor. The motor provides a stable and controlled processing speed for the torsion process. As the motor rotates, the outer PTFE layer uniformly coats the internal fiber structure, thus forming a PTFE@silver-plated Nylon fiber structure.

[0059] Step 2: Wrap the fibers around the iron mandrel in the same chiral direction and fix both ends. Then, heat the fibers and the mold at 150 degrees Celsius for 300 minutes to form a stable helical structure of PTFE@silver-plated Nylon artificial muscle fibers.

[0060] Step 3: Preparation of the hydrogen evolution confinement-driven electrolyte. The electrolyte solution is prepared by using lithium sulfate (Li₂SO₄) at a concentration of 1 mol / L. -1 It is made by mixing it with an aqueous solution in a certain proportion.

[0061] Step 4: Construction of the working device. An electrochemical biomimetic muscle fiber working device was constructed using a two-electrode system, with PTFE@silver-plated Nylon spiral fiber as the working electrode, a platinum sheet as the counter electrode, and a 1 mol / L electrolyte. -1 Lithium sulfate aqueous solution.

[0062] Example 5 This embodiment provides a gas-confined artificial muscle fiber system of different materials, and the specific preparation process is shown below.

[0063] Step 1: Preparation of PTFE@CNT@Nylon composite fibers. 20cm long CNT narrow strips and Nylon fibers are stacked and wrapped in parallel. Then, two 1cm wide PTFE strips are wrapped inside and fixed to a motor. The motor provides a stable and controlled processing speed for the torsion process. As the motor rotates, the outer PTFE layer uniformly coats the internal fiber structure, thus forming a PTFE@CNT@Nylon fiber structure.

[0064] Step 2: Wrap the fibers around the iron mandrel in the same chiral direction and fix both ends. Then, heat the fibers and the mold at 150 degrees Celsius for 300 minutes to form a stable helical structure of PTFE@CNT@Nylon artificial muscle fibers.

[0065] Step 3: Preparation of the hydrogen evolution confinement-driven electrolyte. The electrolyte solution is prepared by dissolving sodium sulfate (Na₂SO₄) at a concentration of 1 mol / L. -1 It is made by mixing it with an aqueous solution in a certain proportion.

[0066] Step 4: Construction of the working device. An electrochemical biomimetic muscle fiber working device was constructed using a two-electrode system, with PTFE@CNT@Nylon helical fibers as the working electrode, a platinum sheet as the counter electrode, and a 1 mol / L electrolyte. -1 Sodium sulfate aqueous solution.

[0067] Example 6 This embodiment provides a gas-confined artificial muscle fiber system of different materials, and the specific preparation process is shown below.

[0068] Step 1: Preparation of PTFE@CNT@Nylon composite fibers. 20cm long CNT narrow strips and Nylon fibers are stacked and wrapped in parallel. Then, two 1cm wide PTFE strips are wrapped inside and fixed to a motor. The motor provides a stable and controlled processing speed for the torsion process. As the motor rotates, the outer PTFE layer uniformly coats the internal fiber structure, thus forming a PTFE@CNT@Nylon fiber structure.

[0069] Step 2: Wrap the fibers around the iron mandrel in the same chiral direction and fix both ends. Then, heat the fibers and the mold at 150 degrees Celsius for 300 minutes to form a stable helical structure of PTFE@CNT@Nylon artificial muscle fibers.

[0070] Step 3: Preparation of the hydrogen evolution confinement-driven electrolyte. The electrolyte solution is prepared by dissolving potassium sulfate (K₂SO₄) in 1 mol / L solution. -1 It is made by mixing it with an aqueous solution in a certain proportion.

[0071] Step 4: Construction of the working device. An electrochemical biomimetic muscle fiber working device was constructed using a two-electrode system, with PTFE@CNT@Nylon helical fibers as the working electrode, a platinum sheet as the counter electrode, and a 1 mol / L electrolyte. -1 Potassium sulfate aqueous solution.

[0072] Example 7 This embodiment provides a gas-confined artificial muscle fiber system of different materials, and the specific preparation process is shown below.

[0073] Step 1: Preparation of ETFE@silver-plated Nylon composite fibers. A 20cm long silver-plated Nylon fiber is wrapped with two 1cm wide strips of ETFE and fixed to a motor. The motor provides a stable and controlled processing speed for the torsion process. As the motor rotates, the outer ETFE layer evenly coats the internal fiber structure, thus forming the ETFE@silver-plated Nylon fiber structure.

[0074] Step 2: Wrap the fibers around the iron mandrel in the same chiral direction and fix both ends. Then, heat the fibers and the mold at 150 degrees Celsius for 300 minutes to form a stable helical structure of ETFE@silver-plated Nylon artificial muscle fibers.

[0075] Step 3: Preparation of the hydrogen evolution confinement-driven electrolyte. The electrolyte solution is prepared by using lithium sulfate (Li₂SO₄) at a concentration of 1 mol / L. -1 It is made by mixing it with an aqueous solution in a certain proportion.

[0076] Step 4: Construction of the working device. An electrochemical biomimetic muscle fiber working device was constructed using a two-electrode system, with ETFE@silver-plated Nylon spiral fibers as the working electrode, a platinum sheet as the counter electrode, and a 1 mol / L electrolyte. -1 Lithium sulfate aqueous solution.

[0077] The artificial muscle fiber systems prepared in Examples 4-7 above have similar gas confinement driving functions as those in Examples 1-2, and will not be described again here.

[0078] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A gas-confinement-driven artificial muscle fiber system, characterized by, It includes artificial muscle fibers and an electrolyte, wherein the artificial muscle fibers are placed in the electrolyte and include a core and a sheath, and are twisted and shaped into an overtwisted spiral state; The sheath is selected from a material with electrolyte-loving properties, allowing the electrolyte to pass through and contact the mandrel. The mandrel is made of a conductive material. When the mandrel acts as an electrode to electrolyze the electrolyte, a gas-filled space is formed between the mandrel and the sheath, causing the artificial muscle fiber to expand radially. This radial expansion is converted into an axial driving force.

2. The artificial muscle fiber system according to claim 1, characterized by, The sheath also has gas permeability properties, allowing the gas filler to gradually permeate out from between the mandrel and the sheath.

3. The artificial muscle fiber system according to claim 1 or 2, characterized by, The sheath material includes any one or a combination of two or more of hydrophilic PTFE, ETFE, and Nafion.

4. The artificial muscle fiber system according to claim 3, characterized by, The thickness of the sheath is 150-250 μm.

5. The artificial muscle fiber system according to claim 1, characterized in that, It also includes a counter electrode, which, together with the artificial muscle fiber, forms the anode and cathode, and is placed in the electrolyte.

6. The artificial muscle fiber system according to claim 5, characterized in that, The electrode is in the form of fibers and is coiled and wrapped around the artificial muscle fibers.

7. The artificial muscle fiber system according to claim 1, characterized in that, The mandrel comprises a core and a wrapping layer in the radial direction from the inside to the outside. The core is made of a polymer material, and the wrapping layer is made of a nano-carbon material and / or a metal.

8. The artificial muscle fiber system according to claim 1, characterized in that, The polymeric material includes any one or a combination of two or more of nylon, polyethylene, and polyester; And / or, the nano-carbon material includes any one or a combination of two of carbon nanotubes and graphene; And / or, the metal includes any one or a combination of two of silver and platinum.

9. The application of the artificial muscle fiber system according to any one of claims 1-8 in the field of manufacturing soft robots.

10. An underwater robot, characterized in that, When the underwater robot is in water, the drive structure of the underwater robot includes the artificial muscle fiber system as described in any one of claims 1-8, and uses the surrounding water as an electrolyte to perform the drive.

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