Micro-clamping system based on optical fiber and state monitoring method thereof

Abstract

The invention relates to the technical field of micro-clamping, in particular to a micro-clamping system based on an optical fiber and a state monitoring method of the micro-clamping system. The micro-clamping system based on the optical fiber comprises a clamping jaw, a transmission structure, an electromagnetic response module, the single-mode optical fiber and a solenoid. One end of the transmission structure is located on the end face of the single-mode optical fiber, the other end of the transmission structure is connected with the clamping jaw, and the transmission structure is connected with the electromagnetic response module; an FP cavity is formed between the electromagnetic response module and the end face of the single-mode optical fiber, and the solenoid is wound on the side surface of the single-mode optical fiber. According to the micro-clamping system based on the optical fiber, contraction and release of the clamping jaw of the micro-clamping system based on the optical fiber are achieved in an electromagnetic response mode, the clamping jaw is not affected by a heat-sensitive material any more, accurate control and positioning of micro-clamping can be achieved, and meanwhile the state of the micro-clamping system based on the optical fiber can be accurately monitored through the FP cavity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-gripping, in particular to a micro-gripping system based on an optical fiber and a state monitoring method thereof. BACKGROUND

[0002] Micro-grippers have very important applications in many fields such as bioengineering, clinical medicine, micro-opto-electro-mechanical device assembly, optical fiber communication and sensing, micro-nano material and structure characterization, microfluidics, intelligent robots, etc. For example, in biological cell manipulation and analysis, micro-grippers can be used for precise gripping of cell tissues, providing a basic tool for cell research, biomedical diagnosis, drug screening, etc. In clinical medical operations, micro-grippers can grip and position biological tissues and blood vessels, and are particularly suitable for high-precision tasks such as local drug injection and minimally invasive surgery. At present, most traditional micro-grippers based on optical fibers use photo-thermal driving, that is, the transmission of light in the optical fiber triggers the deformation of heat-sensitive substances at the end of the optical fiber, thereby triggering the opening and closing of the gripper. Therefore, in the traditional micro-gripper based on the optical fiber, the material properties of the optical fiber may be affected by environmental factors such as temperature and humidity, thereby affecting the gripping precision due to changes in the physical properties of the optical fiber. SUMMARY

[0003] The embodiments of the present application provide a micro-gripping system based on an optical fiber and a state monitoring method thereof, which can solve the problem of low gripping precision of the traditional micro-gripper based on the optical fiber.

[0004] In one aspect of the embodiments of the present application, a micro-gripping system based on an optical fiber is provided, which comprises a gripper jaw, a transmission structure, an electromagnetic response module, a single-mode optical fiber and a solenoid; one end of the transmission structure is located at the end face of the single-mode optical fiber, the other end of the transmission structure is connected with the gripper jaw, and the transmission structure is connected with the electromagnetic response module; an FP cavity is formed between the electromagnetic response module and the end face of the single-mode optical fiber, and the solenoid is wound on the side surface of the single-mode optical fiber. When the solenoid is forward energized, a magnetic field in a first direction is generated to make the electromagnetic response module move downward due to a first magnetic field force provided by the magnetic field in the first direction, thereby driving the transmission structure to have a first deformation to make the gripper jaw contract. When the forward energization of the solenoid is canceled, the electromagnetic response module moves upward due to the disappearance of the first magnetic field force, thereby driving the transmission structure to have a second deformation to make the gripper jaw release. The state of the gripper jaw is monitored by determining the reflection signal of the optical signal transmitted by the single-mode optical fiber in the FP cavity.

[0005] Optionally, the transmission structure includes a base, a support, a first transmission part, and a second transmission part; One end of the base is fixedly connected to the end face of the single-mode optical fiber, the other end of the base is connected to the first transmission part and the support part, and the support part is connected to the bottom of the electromagnetic response module. The first transmission part is connected to the second transmission part and the gripper, and an angle is formed between the first transmission part and the base, and the size of the angle is adjustable; One end of the second transmission part is connected to the top of the electromagnetic response module, and the other end of the second transmission part is connected to the first transmission part; When the electromagnetic response module moves downward, it drives the second transmission part and the first transmission part, so that the angle between the first transmission part and the base part becomes smaller, thereby causing the gripper to retract. When the electromagnetic response module moves upward, it drives the second transmission part and the first transmission part, so that the angle between the first transmission part and the base increases, thereby causing the gripper to release.

[0006] Optionally, the first deformation involves the first and second transmission parts moving downwards to reduce the angle between the first transmission part and the base; the second deformation involves the first and second transmission parts moving upwards to increase the angle between the first transmission part and the base.

[0007] Optionally, when the optical signal transmitted within the single-mode fiber reaches the end face of the single-mode fiber, a portion of the optical signal is reflected to form a first reflected signal; another portion of the optical signal passes through the end face of the single-mode fiber, through the FP cavity, and reaches the bottom of the electromagnetic response module, where it is reflected by the bottom of the electromagnetic response module to form a second reflected optical signal; the state of the gripper is monitored using the first and second reflected optical signals. The reflected signal includes the first reflected light signal and the second reflected light signal.

[0008] Optionally, the gripper and the transmission structure are fabricated using photoresist, and the electromagnetic response module is fabricated using photoresist doped with ferromagnetic nanoparticles.

[0009] According to one aspect of the embodiments of this application, a state monitoring method for an optical fiber-based micro-clamping system is provided, applied to the optical fiber-based micro-clamping system as described above, the method comprising: An optical signal is injected into a single-mode optical fiber, and a first reflected optical signal and a second reflected optical signal are received. The first reflected optical signal is formed after the optical signal is reflected by the end face of the single-mode optical fiber, and the second reflected optical signal is formed after the optical signal passes through the end face of the single-mode optical fiber and is reflected by the electromagnetic response module. Determine the reflectivity of the first reflected light signal and the reflectivity of the second reflected light signal; Determine the intensity of the optical signal and the intensity of the interference light formed by the first reflected optical signal and the second reflected optical signal; The phase difference between the first reflected light signal and the second reflected light signal is determined based on the intensity of the light signal, the intensity of the interference light, the reflectivity of the first reflected light signal, and the reflectivity of the second reflected light signal. The state of the fiber-optic-based micro-clamping system is monitored based on the phase difference.

[0010] Optionally, monitoring the state of the fiber-optic-based micro-clamping system based on the phase difference includes: Determine the refractive index of the medium within the FP cavity; The cavity length of the FP cavity is determined based on the refractive index of the medium and the phase difference, and the cavity length is the distance between the end face of the single-mode fiber and the electromagnetic response module. Determine the initial distance between the electromagnetic response module and the end face of the single-mode optical fiber in its original state; The cavity length is compared with the initial distance to determine the state of the electromagnetic response module, so as to monitor the state of the fiber-optic-based micro-clamping system based on the state of the electromagnetic response module.

[0011] The embodiments of this application include at least the following beneficial effects: According to the fiber optic-based micro-gripping system and its state monitoring method provided in this application, by forward energizing the solenoid, a magnetic field with a first direction is generated, thereby attracting the electromagnetic response module (i.e., due to the action of the first magnetic field force), causing the electromagnetic response module to move downward, which in turn drives the transmission structure to undergo a first deformation. That is, when the transmission structure undergoes the first deformation, the gripper can retract, and the gripper retraction and gripping function is realized through electromagnetic response. When the forward energizing is canceled, since the solenoid is not energized, the magnetic field in the first direction disappears, and the first magnetic field force disappears. The attraction force on the electromagnetic response module also disappears, and the transmission structure will return to its original state due to a second deformation (or elastic deformation). That is, after the first magnetic field force disappears, the electromagnetic response module moves upward, causing the gripper to release, thereby realizing the gripper release function.

[0012] Meanwhile, a method for monitoring the status of a fiber-optic micro-clamping system is also provided. This method involves analyzing the reflected signal of the optical signal transmitted through the single-mode fiber in the FP cavity to determine the distance between the electromagnetic response module and the end face of the single-mode fiber. Based on this distance, it can be determined whether the gripper is in a contracted or released state.

[0013] In summary, this application utilizes electromagnetic response to achieve the contraction and release of the grippers in a fiber-optic-based micro-gripping system, which is no longer affected by thermal materials. This enables precise control and positioning of the micro-gripping, while the FP cavity allows for precise monitoring of the status of the fiber-optic-based micro-gripping system. Attached Figure Description

[0014] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0015] Figure 1 A schematic diagram of the gripper of the fiber-optic-based micro-gripping system provided in the embodiments of this application in the released state (or original state); Figure 2 A schematic diagram of the gripper of the fiber-optic micro-gripping system provided in this application embodiment in a retracted state (or gripping state); Figure 3 A schematic diagram of the gripper of the fiber-optic-based micro-gripping system provided in the embodiments of this application in its original state; Figure 4 The optical path diagram of the reflected signal provided in the embodiments of this application; Figure 5 This application provides an optical path diagram for femtosecond laser two-photon printing. Figure 6 Figure 1 shows the mechanical and optical performance analysis of the fiber-optic-based micro-clamping system. Figure 7 A schematic flowchart illustrating the status monitoring method for a fiber-optic-based micro-clamping system provided in this application embodiment.

[0016] Figure Labels 1. Gripper; 2. Transmission structure; 21. Base; 22. Support; 23. First transmission part; 24. Second transmission part; 3. Electromagnetic response module; 4. Single-mode optical fiber; 5. Solenoid; 6. FP cavity. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0018] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0019] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0021] First, the following summarizes the shortcomings of each type of micro gripper mentioned above.

[0022] First, the disadvantages of piezoelectric grippers: (1) The displacement is limited, usually at the micrometer level, and a complex mechanism is required to amplify the displacement.

[0023] (2) The driving voltage is too high, which can easily lead to device fatigue or damage; (3) The manufacturing process is complex and the cost is high.

[0024] Second, the disadvantages of electromagnetic grippers: (1) The device size is relatively large, making it unsuitable for ultra-miniaturization applications; (2) The magnetic field is easily affected by external interference, and its stability is limited; (3) Due to the small size of the micro electromagnetic clamp, it is difficult to achieve extremely high precision in the manufacturing and assembly process.

[0025] Third, the disadvantages of shape memory alloy grippers: (1) Shape recovery is a thermally or electrically activated process, so the response speed is slow and the recovery time is long; (2) During thermal cycling, shape memory alloys will experience fatigue and their performance will decline; (3) Its deformation characteristics are affected by various factors such as temperature and stress, so its accuracy is limited.

[0026] Fourth, the disadvantages of electrostatic grippers: (1) The driving force is small, requiring a higher voltage to drive, which can easily cause electrical breakdown; (2) The electrostatic force is greatly affected by humidity and surface condition, and its environmental adaptability is poor; (3) Long-term use may lead to charge accumulation, affecting reliability.

[0027] Fifth, the disadvantages of electrothermal / photothermal clamps: (1) It has a large thermal inertia and a slow response speed; (2) The energy consumption is relatively large, and the temperature rise may affect the device life or cause thermal drift; (3) Uneven thermal expansion and contraction may lead to a decrease in accuracy.

[0028] Sixth, the disadvantages of fiber optic-based microgrippers: (1) The properties of optical fiber materials may be affected by environmental factors, such as temperature and humidity, which may lead to changes in the physical properties of the optical fiber and affect its accuracy. (2) The prepared micro gripper cannot transmit and amplify the gripper force and gripper displacement, thus it does not have the sensing and feedback function of the gripper itself.

[0029] According to one aspect of the embodiments of this application, a fiber-optic-based micro-clamping system is proposed. The fiber-optic-based micro-clamping system includes a gripper 1, a transmission structure 2, an electromagnetic response module 3, a single-mode fiber 4, and a solenoid 5. One end of the transmission structure 2 is located on the end face of the single-mode fiber 4, and the other end of the transmission structure 2 is connected to the gripper 1. The transmission structure 2 is connected to the electromagnetic response module 3. An FP cavity 6 is formed between the electromagnetic response module 3 and the end face of the single-mode fiber 4. The solenoid 5 is wound around the side surface of the single-mode fiber 4. When the solenoid 5 is energized in the positive direction, it generates a magnetic field in the first direction, causing the electromagnetic response module 3 to move downward due to the first magnetic force provided by the magnetic field in the first direction, thereby causing the transmission structure 2 to undergo a first deformation, so that the gripper 1 retracts. When the forward energization of the solenoid 5 is removed, the electromagnetic response module 3 moves upward due to the disappearance of the first magnetic field force, thereby causing the transmission structure 2 to undergo a second deformation, so that the gripper 1 is released; The state of the gripper 1 is monitored by determining the reflection signal of the optical signal transmitted by the single-mode fiber 4 in the FP cavity 6.

[0030] The gripper 1 and transmission structure 2 in this application are fabricated using photoresist. Specifically, the photoresist is printed using femtosecond laser printing technology to obtain the gripper 1 and transmission structure 2. After obtaining the gripper 1 and transmission structure 2, ferromagnetic nanoparticles are doped into the photoresist to print the electromagnetic response module 3, giving the electromagnetic response module 3 magnetic response characteristics so that it can subsequently realize the electromagnetic drive function. It is worth noting that this application uses a two-stage printing technology to print the gripper 1, transmission structure 2, and electromagnetic response module 3. First, the photoresist without ferromagnetic nanoparticles is printed to obtain the gripper 1 and transmission structure 2, and then the photoresist doped with ferromagnetic nanoparticles is printed to obtain the electromagnetic response module 3.

[0031] Please refer to Figure 1 , Figure 2 and Figure 3 As shown, Figure 1 This is a schematic diagram of the gripper 1 of the fiber optic-based micro-gripping system in the released state (or original state). Figure 2 This is a schematic diagram of the gripper 1 of the fiber optic micro-gripping system in a retracted state (or gripping state). Figure 3 This is a schematic diagram of a fiber-optic-based micro-clamping system, in which... Figure 3 (a) is a schematic diagram showing that the number of gripper arms of gripper 1 is 2. Figure 3 (b) is a schematic diagram showing that the number of gripper arms 1 of gripper 1 is 3. The following is combined with Figure 1 , Figure 2 and Figure 3 The fiber optic-based micro-clamping system will be described in detail below: First, such as Figure 1 or Figure 2 As shown, the transmission structure 2 consists of a base 21, a support 22, a first transmission part 23, and a second transmission part 24. One end of the base 21 is fixedly connected to the end face of the single-mode optical fiber 4, and the other end of the base 21 is connected to the first transmission part 23 and the support 22. The support 22 is connected to the bottom of the electromagnetic response module 3. The support 22 can undergo elastic deformation. During the downward movement of the electromagnetic response module 3, the support 22... Figure 2As shown, when the electromagnetic response module 3 undergoes a slight downward bending deformation and is not attracted by an attractive force, it indicates that the first magnetic field force has disappeared. At this time, it will return to its original shape due to the elastic deformation of the support part 22. Combining the disappearance of the first magnetic field force and the elastic deformation of the support part 22, the electromagnetic response module 3 will move upward.

[0032] The first transmission part 23 and the base 21 form an angle, and the size of the angle is adjustable. That is, when the electromagnetic response module 3 moves downward, it drives the second transmission part 24 and the first transmission part 23, so that the angle between the first transmission part 23 and the base 21 decreases, thereby causing the gripper 1 to retract. When the electromagnetic response module 3 moves upward, it drives the second transmission part 24 and the first transmission part 23, so that the angle between the first transmission part 23 and the base 21 increases, thereby causing the gripper 1 to release.

[0033] The first deformation involves the first transmission part 23 and the second transmission part 24 moving downwards, thereby reducing the angle between the first transmission part 23 and the base 21; the second deformation involves the first transmission part 23 and the second transmission part 24 moving upwards, thereby increasing the angle between the first transmission part 23 and the base 21.

[0034] like Figure 2 As shown, the solenoid 5 is wound around the side surface of the single-mode optical fiber 4. When the solenoid 5 is energized in the forward direction, the forward energization is used to characterize that the current direction inside the solenoid 5 is positive. That is, under the positive current, a first magnetic field force can be generated to attract the electromagnetic response module 3.

[0035] like Figure 1 As shown, when the forward energization of the solenoid 5 is canceled, it will return to normal. Figure 1 or Figure 3 As shown in (a), the support part 22 is a straight line, supporting the electromagnetic response module 3. Simultaneously, as the electromagnetic response module 3 moves upward, it drives the first transmission part 23 and the second transmission part 24 upward, at which point the gripper 1 is released. It should be noted that... Figure 3 This is a schematic diagram of the fiber-optic-based micro-gripping system in its original state (i.e., gripper 1 is in the released state).

[0036] Furthermore, FP cavity 6 refers to a passive optical resonant cavity, such as... Figure 1As shown, FP cavity 6 refers to the cavity formed between the end face of single-mode fiber 4 and the bottom surface of electromagnetic response module 3. The cavity length of FP cavity 6 (the distance between the end face of single-mode fiber 4 and electromagnetic response module 3) will change with the movement of electromagnetic response module 3. Therefore, by analyzing the reflected signal of the optical signal transmitted by single-mode fiber 4 in FP cavity 6, the position change of electromagnetic response module 3 can be known, and then the state of gripper 1, whether it is contraction or release, can be determined based on the position change of electromagnetic response module 3.

[0037] Specifically, for example Figure 4 As shown, when the optical signal transmitted within the single-mode fiber 4 reaches the end face of the single-mode fiber 4, a portion of the optical signal is reflected, forming a first reflected signal. M 1. Another portion of the optical signal passes through the end face of the single-mode fiber 4, through the FP cavity 6, and reaches the bottom of the electromagnetic response module 3, where it is reflected by the bottom of the electromagnetic response module 3 to form a second reflected optical signal. M 2, then for M 1 and M By performing analysis, the status of a fiber optic-based micro-clamping system can be monitored.

[0038] According to one aspect of the embodiments of this application, a state monitoring method for an optical fiber-based micro-clamping system is provided, applied to the optical fiber-based micro-clamping system as described above, such as... Figure 7 As shown, Figure 7 This is a flowchart illustrating a state monitoring method for a fiber-optic-based micro-gripping system, which includes, but is not limited to, the following steps: Step S1: Inject an optical signal into a single-mode fiber and receive a first reflected optical signal and a second reflected optical signal. The first reflected optical signal is formed after the optical signal is reflected by the end face of the single-mode fiber, and the second reflected optical signal is formed after the optical signal passes through the end face of the single-mode fiber and is reflected by the electromagnetic response module. Step S2: Determine the reflectivity of the first reflected light signal and the reflectivity of the second reflected light signal; Step S3: Determine the intensity of the optical signal and the intensity of the interference light formed by the first reflected optical signal and the second reflected optical signal; Step S4: Determine the phase difference between the first reflected light signal and the second reflected light signal based on the intensity of the light signal, the intensity of the interference light, the reflectivity of the first reflected light signal, and the reflectivity of the second reflected light signal; Step S5: Monitor the status of the fiber-optic-based micro-clamping system based on the phase difference.

[0039] Furthermore, the monitoring of the state of the fiber-optic-based micro-clamping system based on the phase difference includes: Determine the refractive index of the medium within the FP cavity; The cavity length of the FP cavity is determined based on the refractive index of the medium and the phase difference, and the cavity length is the distance between the end face of the single-mode fiber and the electromagnetic response module. Determine the initial distance between the electromagnetic response module and the end face of the single-mode optical fiber in its original state; The cavity length is compared with the initial distance to determine the state of the electromagnetic response module, so as to monitor the state of the fiber-optic-based micro-clamping system based on the state of the electromagnetic response module.

[0040] The reflected light (first reflected light signal and second reflected light signal) from the two reflecting surfaces (i.e., the end face of the single-mode fiber and the bottom surface of the electromagnetic response module) mainly undergoes two-beam interference. The intensity of the interference light in the two-beam interference... for:

[0041] The intensity of the incident light. for reflectivity, for reflectivity, The phase difference between the first and second reflected light signals caused by the resonant cavity (FP cavity):

[0042] The refractive index of the medium inside the resonant cavity (FP cavity) is... The cavity length is the resonant cavity (FP cavity). λ is the wavelength of light in a vacuum.

[0043] When phase satisfy When the wavelength is an integer multiple of , the characteristic valley wavelength of its output interference spectrum satisfies:

[0044] In the above formula, For positive integers, the spectral free path for:

[0045] When the electromagnetic response module is subjected to a magnetic force, it pulls the micro-clamping device to undergo elastic deformation, thereby changing the cavity length of the resonant cavity. This change in cavity length leads to a change in the optical path difference of the reflected light, causing a shift in the central spectral wavelength. The wavelength shift is characterized, thus enabling the monitoring of the status of the fiber-optic-based micro-clamping system.

[0046] Based on the above analysis, the state of the fiber-optic-based micro-clamping system can be determined by utilizing the optical path length of the reflected light or the interference light, or by utilizing the intensity of the optical signal and the intensity of the interference light to determine the phase difference between the first and second reflected light signals, thereby determining the cavity length of the resonant cavity (FP cavity), and thus determining the state of the fiber-optic-based micro-clamping system. Therefore, based on the structure of the fiber-optic-based micro-clamping system, the embodiments of this application can also achieve state monitoring of the fiber-optic-based micro-clamping system using the above methods.

[0047] In some embodiments, the fiber optic micro-gripper is fabricated as follows: Micro-gripper structures were fabricated on the fiber end face using femtosecond laser TPP (twin-photon polymerization) printing technology. The femtosecond laser pulses (SpOne-8-SHG, wavelength 520nm) were introduced into the micro / nano fabrication platform (Newport, mFab-G). That is, the linearly polarized femtosecond laser beam emitted by the laser passes sequentially through a half-wave plate and a Glan polarizer ( Figure 5 (as shown in the GP) and 1 / 4 wave plate (such as Figure 5 (As shown). The half-wave plate's rotation direction can be controlled by a motor, thereby adjusting the angle between the polarization direction of the incident femtosecond laser and the optical axis of the Glan polarizer, thus controlling the laser intensity. Simultaneously, the beam expander expands the laser beam, reducing the divergence angle of the femtosecond laser transmission and facilitating the formation of a smaller spot by the microscope objective at the system's back end, improving the accuracy of two-photon polymerization printing. The angle between the optical axis of the quarter-wave plate and the optical axis of the Glan polarizer is set to 45 degrees. When the femtosecond laser passes through the quarter-wave plate, the originally linearly polarized light becomes circularly polarized light, avoiding anisotropic effects introduced by the polarization direction during two-photon polymerization printing. The femtosecond laser is then focused onto the end face of a single-mode fiber by a micro-oil microscope. Before processing, the single-mode fiber is inserted into a fiber ceramic ferrule and fixed on a multi-axis micro / nano displacement motor platform. Photoresist is filled between the micro-oil microscope and the fiber ferrule. Printing is then performed, and a CCD camera monitors the 3D printing process in real time. Meanwhile, the electromagnetic response module designed in this application is printed using photoresist doped with ferromagnetic nanoparticles, while the grippers and transmission structure are fabricated solely using photoresist. Therefore, a two-stage printing technique is required when fabricating the electromagnetic response module. First, the transmission structure and grippers are fabricated on the fiber end face using photoresist without ferromagnetic nanoparticles; then, the electromagnetic response module is printed on top of the transmission structure using photoresist doped with ferromagnetic nanoparticles. After two-photon printing, post-baking, developing, and fixing processes are required to further solidify the entire self-feedback fiber microgripper structure and remove uncured resin material. After printing, developing and fixing yield the designed fiber-based microgripping system.

[0048] To optimize the performance of the designed fiber-optic-based micro-clamping system, this application conducted mechanical and optical performance analyses. Numerical analyses were performed using Abaqus and Comsol, such as... Figure 6 As shown, since the structure of this fiber-optic-based micro-clamping system is made of photoresist, the Poisson's ratio and Young's modulus of the photoresist were incorporated into the parameter settings, and the changes in deformation, FP cavity length, and corresponding reflection spectrum were studied when different magnitudes of electromagnetic force were applied.

[0049] Figure 6 (a) The electromagnetic response module is driven by electromagnetic force (i.e., the first magnetic field force) to drive the gripper to move laterally and achieve clamping. Figure 6 (b) shows the linear relationship between electromagnetic force and gripper displacement. Figure 6 (c) shows the reflection interference spectrum drift caused by the deformation of the FP cavity.

[0050] in, Figure 6 (a) shows the displacement of the grippers of the micro gripper when an electromagnetic force of 0.25 μN is applied. It can be seen that the two grippers displace 4 μm towards each other. Figure 6 (b) shows the relationship between the applied electromagnetic force and the lateral displacement of the gripper, which has a good linear relationship. Figure 6 (c) The figure shows the change in the normalized reflection spectrum when the cavity length of the fiber optic cable (FP) changes. It can be seen that the change in cavity length leads to wavelength shift. In summary, through numerical analysis, it is found that the structure of this fiber-optic-based micro-clamping system has good characterization properties.

[0051] Meanwhile, for the gripping function of this fiber-optic-based micro-gripper system, energizing the solenoid allows it to apply electromagnetic force to the micro-gripper, reducing the distance between the grippers to grasp the object. Gradually increasing the electromagnetic force causes the gripper spacing to decrease, the corresponding FP cavity length to change gradually, and the drift in the reflection spectrum to increase gradually. Until the gripper spacing is just enough to grasp the object, further increasing the electromagnetic force at this point significantly reduces the rate of change in gripper spacing, and the corresponding drift in the reflection spectrum does not change significantly; the subsequent process is no longer linear. Therefore, the gripping status of the fiber-optic-based micro-gripper system can be determined by observing the drift in the reflection spectrum, allowing for real-time monitoring.

[0052] The key points of the embodiments of this application are summarized below: 1. A fiber-based micro-clamping system, including grippers, transmission mechanisms, and electromagnetic response modules, is fabricated directly and in one step on the end face of a single-mode fiber, achieving miniaturization and integration of clamping functions; Ferromagnetic nanoparticles are doped into the material of the electromagnetic response module to make it sensitive to external electromagnetic fields, thereby realizing the active electromagnetic drive clamping function.

[0053] 2. The micro gripper structure has an internal FP interference cavity composed of a single-mode fiber end face and the lower surface of the electromagnetic response module; By measuring the interference spectrum drift caused by the minute change in the cavity length of the FP cavity after the electromagnetic response module is subjected to force, real-time optical feedback detection of the clamping force, gripper displacement, and clamping status of the fiber-optic micro-clamping system can be achieved.

[0054] 3. First, use pure photoresist without doped materials to print the gripper and transmission mechanism on the end face of the optical fiber; then use photoresist doped with ferromagnetic nanoparticles to print the electromagnetic response module on the basis of the prepared transmission mechanism, so as to ensure the material differentiation and effective integration of the functional areas of the microstructure.

[0055] 4. A solenoid is wound around the outer surface of the single-mode optical fiber, and an adjustable electromagnetic field is generated by external power control; this enables active control of the electromagnetic response module and follow-up control of the gripper. By adjusting the magnitude and direction of the electromagnetic force, the closing or opening action of the gripper is precisely controlled to achieve the contraction and release of the gripper.

[0056] Based on this, the present application has the following beneficial effects: 1. Advantages of miniaturization and high integration This application utilizes femtosecond laser two-photon polymerization technology to directly print grippers, transmission mechanisms, and electromagnetic response modules on the end face of a single-mode fiber in a single operation. This not only highly integrates driving and sensing functions into a single microstructure, effectively overcoming the problems of complex structure, large size, and difficulty in miniaturization of traditional micro grippers, but also simplifies the fabrication process and improves the manufacturing precision and reliability of microdevices.

[0057] 2. Advantages of real-time self-feedback monitoring and control This application innovatively integrates an FP interferometer cavity within the micro-gripping structure (i.e., the micro-gripper), enabling real-time and precise optical feedback monitoring of clamping force, gripper displacement, and clamping status during the clamping process. Compared to traditional micro-grippers that require additional external sensors or optical microscopy systems for status monitoring, this application significantly reduces the complexity of the monitoring system and enhances the device's self-sensing and adaptive performance.

[0058] 3. Advantages of precise control via active electromagnetic drive This application utilizes an electromagnetic response module doped with ferromagnetic nanoparticles to actively drive a micro-gripper under the influence of an external solenoid electromagnetic field, offering advantages such as rapid response, precise control, and stable reliability. Furthermore, the electromagnetic drive method allows for precise control of clamping force and displacement through simple adjustment of the electromagnetic field strength and direction, avoiding the drawbacks of traditional thermally driven devices such as high energy consumption, slow response, and thermal drift.

[0059] 4. Advantages of wide application and strong environmental adaptability Fiber optic microgrippers, with their excellent biocompatibility, electromagnetic interference resistance, and miniature probe structure, are well-suited for various applications such as biomedicine, precision optical assembly, microelectronic device assembly, and micro-nano manipulation. They can operate stably in a wider range of complex environments and confined spaces, meeting the urgent needs of emerging high-tech fields for precise operation and real-time status monitoring of micro-devices.

[0060] In the foregoing description of this specification, the references to terms such as "one embodiment," "another embodiment," or "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

[0062] The above is a detailed description of the preferred embodiments of this application, but this application is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A fiber-optic-based micro-clamping system, characterized in that, The fiber-optic-based micro-clamping system includes a gripper, a transmission structure, an electromagnetic response module, a single-mode fiber, and a solenoid. One end of the transmission structure is located on the end face of the single-mode fiber, and the other end of the transmission structure is connected to the gripper. The transmission structure is also connected to the electromagnetic response module. An FP cavity is formed between the electromagnetic response module and the end face of the single-mode fiber, and the solenoid is wound around the side surface of the single-mode fiber. When the solenoid is energized in the forward direction, it generates a magnetic field in the first direction, causing the electromagnetic response module to move downward due to the first magnetic force provided by the magnetic field in the first direction, thereby causing the transmission structure to undergo a first deformation, so that the gripper retracts. When the forward energization of the solenoid is removed, the electromagnetic response module moves upward due to the disappearance of the first magnetic field force, which in turn causes the transmission structure to undergo a second deformation, thereby releasing the gripper; The state of the gripper is monitored by determining the reflection signal of the optical signal transmitted by the single-mode fiber in the FP cavity.

2. The fiber-optic-based micro-clamping system according to claim 1, characterized in that, The transmission structure includes a base, a support, a first transmission part, and a second transmission part; One end of the base is fixedly connected to the end face of the single-mode optical fiber, the other end of the base is connected to the first transmission part and the support part, and the support part is connected to the bottom of the electromagnetic response module. The first transmission part is connected to the second transmission part and the gripper, and an angle is formed between the first transmission part and the base, and the size of the angle is adjustable; One end of the second transmission part is connected to the top of the electromagnetic response module, and the other end of the second transmission part is connected to the first transmission part; When the electromagnetic response module moves downward, it drives the second transmission part and the first transmission part, so that the angle between the first transmission part and the base part becomes smaller, thereby causing the gripper to retract. When the electromagnetic response module moves upward, it drives the second transmission part and the first transmission part, so that the angle between the first transmission part and the base increases, thereby causing the gripper to release.

3. The fiber-optic-based micro-clamping system according to claim 2, characterized in that, The first deformation is that the first transmission part and the second transmission part move downward so that the angle between the first transmission part and the base becomes smaller; the second deformation is that the first transmission part and the second transmission part move upward so that the angle between the first transmission part and the base becomes larger.

4. The fiber-optic-based micro-clamping system according to claim 1, characterized in that, When the optical signal transmitted within the single-mode fiber reaches the end face of the single-mode fiber, a portion of the optical signal is reflected to form a first reflected signal; another portion of the optical signal passes through the end face of the single-mode fiber, through the FP cavity, and reaches the bottom of the electromagnetic response module, where it is reflected by the bottom of the electromagnetic response module to form a second reflected optical signal; the state of the gripper is monitored using the first and second reflected optical signals. The reflected signal includes the first reflected light signal and the second reflected light signal.

5. The fiber-optic-based micro-clamping system according to claim 1, characterized in that, The gripper and the transmission structure are fabricated using photoresist, and the electromagnetic response module is fabricated using photoresist doped with ferromagnetic nanoparticles.

6. A method for monitoring the state of a fiber-optic-based micro-clamping system, characterized in that, Applied to the fiber-optic-based micro-clamping system as described in any one of claims 1-5, the method comprises: An optical signal is injected into a single-mode optical fiber, and a first reflected optical signal and a second reflected optical signal are received. The first reflected optical signal is formed after the optical signal is reflected by the end face of the single-mode optical fiber, and the second reflected optical signal is formed after the optical signal passes through the end face of the single-mode optical fiber and is reflected by the electromagnetic response module. Determine the reflectivity of the first reflected light signal and the reflectivity of the second reflected light signal; Determine the intensity of the optical signal and the intensity of the interference light formed by the first reflected optical signal and the second reflected optical signal; The phase difference between the first reflected light signal and the second reflected light signal is determined based on the intensity of the light signal, the intensity of the interference light, the reflectivity of the first reflected light signal, and the reflectivity of the second reflected light signal. The state of the fiber-optic-based micro-clamping system is monitored based on the phase difference.

7. The state monitoring method for a fiber-optic-based micro-clamping system according to claim 6, characterized in that, The monitoring of the state of the fiber-optic-based micro-clamping system based on the phase difference includes: Determine the refractive index of the medium within the FP cavity; The cavity length of the FP cavity is determined based on the refractive index of the medium and the phase difference, and the cavity length is the distance between the end face of the single-mode fiber and the electromagnetic response module. Determine the initial distance between the electromagnetic response module and the end face of the single-mode optical fiber in its original state; The cavity length is compared with the initial distance to determine the state of the electromagnetic response module, so as to monitor the state of the fiber-optic-based micro-clamping system based on the state of the electromagnetic response module.

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