A simplified three-dimensional deformation reduction system and method based on a single-mode optical fiber

Abstract

The application discloses a kind of based on single-mode optical fiber simplified three-dimensional deformation reduction system and method, belong to optical fiber sensing technical field;System is by light source, optical frequency domain reflectometer, deformation sensing measurement module and signal processing unit composition;Deformation sensing measurement module uses silica gel hose, flexible wire or 3D printing grooved structure as skeleton, single-mode optical fiber is along skeleton cross section and is distributed in 120 ° three edges, and constitutes equivalent three-core sensing structure;Large scene can be directly replaced with coarse optical cable bending three sections and binding tightly;System is in real time by optical frequency domain reflectometer demodulation distributed strain, based on Frenet-Serret framework restores three-dimensional deformation;The application only uses single optical fiber / cable, without fan into fan out module, coupler and multiplex switch, greatly simplifies structure, reduce cost, can be disposable synchronous acquisition strain data, avoid power loss and timing error, applicable to soft robot, minimally invasive intervention, structure health monitoring and the like scene.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic sensing technology, and particularly relates to a simplified three-dimensional deformation restoration system and method based on single-mode fiber. Background Technology

[0002] Three-dimensional deformation reconstruction technology is one of the key technologies in fields such as intelligent structures, robot navigation, and minimally invasive surgery. Existing fiber-optic deformation sensing solutions are mainly divided into two categories: one is quasi-distributed sensing based on fiber Bragg grating arrays, which calculates and inverts deformation through multi-point curvature calculation, but due to limitations in demodulation speed and grating density, it is difficult to balance real-time performance and accuracy; the other is distributed sensing based on optical frequency domain reflectometers combined with multi-core optical fibers, which uses the strain differences among the cores of the multi-core optical fiber to achieve three-dimensional shape reconstruction. Although this technology has shown high-precision potential in fields such as soft robots and interventional instrument navigation, its system architecture has inherent bottlenecks.

[0003] However, multi-core optical fibers are expensive and require complex fan-in and fan-out modules. To obtain spatial strain information, time-division multiplexing is often performed by splitting the light using multiplexed optical switches or optical couplers. Multiplexed optical switches cannot achieve synchronous signal acquisition, and optical couplers cause optical power attenuation. At the same time, the fusion splicing process between multi-core optical fibers and standard single-mode optical fibers is complex, which limits their engineering promotion.

[0004] Therefore, there is an urgent need for a new solution that adapts to the needs of multiple application scenarios, significantly reduces hardware costs and implementation barriers, and provides high real-time performance, high integration and low cost for accurate measurement and shape restoration of 3D deformation. Summary of the Invention

[0005] The purpose of this invention is to provide a simplified three-dimensional deformation reconstruction system and method based on single-mode optical fiber, solving the problems of high cost, high loss, and poor real-time performance caused by multiplexing switching in existing technologies using multi-core optical fibers and fan-in / fan-out modules. This invention constructs an equivalent three-core optical fiber sensing structure in space through a clever triangular distribution method, and also innovatively designs various bending measurement skeletons, providing a direct application solution for skeletonless thick optical cables in large-scale scenarios. This innovative design enables the system to acquire complete spatial strain information in a single, real-time manner using a single single-mode optical fiber or thick optical cable.

[0006] To achieve the above objectives, the present invention provides a simplified three-dimensional deformation reconstruction system based on single-mode optical fiber, comprising: a light source, an optical frequency domain reflectometer, a deformation sensing and measurement module, and a signal processing unit; The light source is connected to the input terminal of the optical frequency domain reflectometer to provide detection light for the entire system; The output end of the optical frequency domain reflectometer is connected to the input end of the single-mode fiber to inject probe light into the single-mode fiber and receive backscattered Rayleigh signals, thereby detecting and demodulating the distributed strain generated at the three equivalent "core" positions in the single-mode fiber in real time. The input end of the deformation sensing measurement module is connected to the output end of the optical frequency domain reflectometer. When subjected to bending deformation, it causes the three equivalent "core" segments of the single-mode fiber to be stretched or compressed, and reflects the backscattered Rayleigh signal back to the optical frequency domain reflectometer. The signal processing unit is connected to the optical frequency domain reflectometer to receive signals and, based on the Frenet-Serret framework, calculate and reconstruct the three-dimensional spatial shape of the bending measurement skeleton according to the distributed strain data at three equivalent "core" locations.

[0007] Preferably, the deformation sensing measurement module consists of a bending measurement frame, a single-mode optical fiber, and encapsulation materials.

[0008] Preferably, the bending measurement frame is any one of the following: a silicone hose, a flexible metal wire with laser-etched grooves, or a grooved structure directly printed from a flexible, highly elastic material using a 3D printer. Preferably, if a thicker optical cable is used instead of a single-mode optical fiber in a large-scale application scenario, a bending measurement skeleton is not used. Instead, an optical cable is directly folded into three sections and bound together in three sections. The three sections are equivalent to three-core optical fibers. In this case, the deformation sensing measurement module is directly composed of a thicker optical cable and encapsulation material.

[0009] Preferably, the single-mode fiber is attached or embedded along the axial direction to the surface of the bending measurement skeleton, and is distributed in a triangular pattern at 120° intervals on the circumference of the cross-section of the bending measurement skeleton, forming a spatially equivalent three-core fiber sensing structure; the grooves on the surface of the flexible metal wire are grooved flexible structures processed by laser lithography and printed by 3D printer, each with three triangular grooves at 120° intervals embedded in them, and the single-mode fiber is embedded in the grooves, fixed and encapsulated.

[0010] Preferably, the bending measurement skeleton material has a diameter of 1-3mm, the flexible elastomer material for fixing the optical fiber is PDMS, and the encapsulation body is a silicone tube or PDMS with an outer diameter of 5mm and an inner diameter of 4mm.

[0011] Preferably, the optical frequency domain reflectometer acquires distributed strain data for all three equivalent "fiber core" locations at once.

[0012] Preferably, the deformation sensing measurement module is packaged in at least two forms: Form 1: A hollow silicone tube is used as the encapsulation body, PDMS is poured into its inner cavity, and a solid composite structure is formed after being heated and cured in an oven. Form 2: After attaching or embedding a single-mode optical fiber into the bending measurement skeleton, multi-layer PDMS is used for multi-layer encapsulation. After each layer is coated, it is placed in an oven to dry, and this process is repeated multiple times to form a protective layer.

[0013] A simplified three-dimensional deformation restoration method based on single-mode fiber, using a simplified three-dimensional deformation restoration system based on single-mode fiber as described in any of the above claims, includes the following steps: S1. After encapsulating the bending measurement skeletons of different thicknesses with attached or embedded single-mode optical fibers using different encapsulation methods, place them in the test environment to cause bending deformation. S2. Using a light source, the optical frequency domain reflectometer is injected with probe light into a single-mode fiber to collect backscattered Rayleigh signals and obtain distributed strain data. S3. Demodulate the strain changes from the distributed strain data to the three equivalent "core" positions on the circumference of the bending measurement skeleton cross section, which are 120° apart. S4. Based on the Frenet-Serret framework, the three-dimensional spatial shape of the bending measurement skeleton is iteratively calculated and restored using strain change data at three equivalent "core" locations.

[0014] Therefore, the simplified three-dimensional deformation restoration system and method based on single-mode optical fiber described above has the following beneficial effects: (1) Three-dimensional deformation restoration can be achieved using only a single ordinary single-mode optical fiber, without the need for expensive or complex devices such as multi-core optical fibers, fan-in and fan-out modules, optical couplers or multiplex switches, which significantly reduces system cost and greatly simplifies hardware architecture; at the same time, the skeleton structure can be omitted in large-scale scenarios, further simplifying the preparation process and reducing application cost. (2) By distributing single-mode optical fibers in a triangular pattern at 120° intervals on the circumference of the cross-section of the bending measurement skeleton, or by directly bending the thick optical cable into three sections and binding them tightly to form an equivalent three-core structure, an equivalent three-core optical fiber sensing structure is constructed in space. A single optical frequency domain reflectometer measurement can acquire the distributed strain data corresponding to the three equivalent "fiber core" positions in one go and in real time, which completely avoids the insertion loss, split power waste and timing error introduced by multi-core separation or channel switching in the traditional scheme. (3) Provides a variety of bending measurement skeleton forms and is suitable for the application of skeletonless thick optical cable in large-scale scene design. At the same time, it completely avoids the complex fusion splicing process between multi-core optical fiber and single-mode optical fiber and the precision assembly requirements of fan-in and fan-out modules, which significantly reduces the threshold of engineering implementation and the difficulty of on-site maintenance. (4) It fully retains the core advantages of optical frequency domain reflectometer technology, such as high spatial resolution, high measurement accuracy, and fully distributed continuous sensing. It can realize continuous, real-time, and high-precision three-dimensional morphological reconstruction of flexible structures and has broad application prospects in the fields of soft robot shape perception, real-time navigation of interventional medical devices, and health monitoring of flexible structures.

[0015] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a simplified three-dimensional deformation reduction system based on single-mode optical fiber according to the present invention. Figure 2 This is a schematic diagram of the cross-sectional distribution of the fiber optic deformation sensing and measurement module attached and embedded in the present invention, wherein (a) is a schematic diagram of the cross-section using the first packaging method, and (b) is a schematic diagram of the cross-section using the second packaging method. Figure 3 This is a schematic diagram of the deformation sensing and measurement module of the present invention, in which a single optical fiber is embedded in a flexible metal wire with a laser lithography groove or a 3D printed grooved structure. Figure 4 The Frenet-Serret framework was used to reconstruct the resulting image after applying uniaxial bending deformation. Figure 5 The three-view comparison diagrams of the restoration results using the Frenet-Serret framework after applying unidirectional bending deformation are shown, where (a) is a schematic diagram of the XY plane projection; (b) is a schematic diagram of the XZ plane projection; and (c) is a schematic diagram of the YZ plane projection. Figure 6 The Frenet-Serret framework was used to reconstruct the resulting image after applying three-dimensional bending deformation. Figure 7 The three-view comparison diagrams of the result restored using the Frenet-Serret framework after applying three-dimensional bending deformation are shown. (a) is a schematic diagram of the XY plane projection; (b) is a schematic diagram of the XZ plane projection; and (c) is a schematic diagram of the YZ plane projection.

[0017] Reference numerals: 1. Signal processing unit; 2. Light source; 3. Optical frequency domain reflectometer; 4. Deformation sensing and measurement module; 5. Single-mode optical fiber; 6. Bending measurement skeleton; 7. PDMS; 8. Outer encapsulation silicone tube; 9. Laser lithography grooved flexible metal wire or 3D printed grooved structure. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0019] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0020] The following is combined with Figures 1-5 The embodiments of the present invention will be described in detail below.

[0021] Example 1 This invention provides a simplified three-dimensional deformation reconstruction system based on single-mode optical fiber, including: an experimental system hardware system, a deformation sensing and measurement module packaging structure, and an analysis method.

[0022] like Figure 1 The diagram shows the overall structure of the simplified three-dimensional deformation restoration system based on single-mode fiber according to the present invention, including: a signal processing unit 1 (PC end), a light source 2, an optical frequency domain reflectometer 3, and a deformation sensing and measurement module 4. The output end of the light source 2 is connected to the input end of the optical frequency domain reflectometer 3 to provide probe light for the entire system; the output end of the optical frequency domain reflectometer 3 is fused to the input end of the deformation sensing and measurement module 4 via an optical fiber fusion splicer to inject probe light into the deformation sensing and measurement module 4 and receive backscattered Rayleigh signals; the signal processing unit 1 is communicatively connected to the optical frequency domain reflectometer 3 via a network cable or GPIB line to receive signals and, based on the Frenet-Serret framework, calculate and restore the three-dimensional spatial shape of the deformation sensing and measurement module 4 using distributed strain data from three equivalent "fiber core" locations.

[0023] like Figure 2 The diagram shown is a schematic cross-sectional distribution of the attachment and embedding fiber optic deformation sensing measurement module of the silicone tubing substrate described in this invention. Figure 2 (a) is a cross-sectional schematic diagram using the first packaging method. Figure 2(b) is a cross-sectional schematic diagram using the second encapsulation method. The deformation sensing measurement module 4 uses a bending measurement frame 6 as the bending measurement frame. The silicone tubing has a diameter of 1-3 mm and is attached or embedded axially to the outer surface of the bending measurement frame 6 by single-mode optical fibers 5. These fibers are arranged in a triangular pattern at 120° intervals on the circumference of the cross-section of the bending measurement frame 6 to form a spatially equivalent three-core optical fiber sensing structure. The flexible elastomer material for fixing the optical fiber is PDMS7, and the encapsulation body is a silicone tubing 8 or PDMS7 with an outer diameter of 5 mm and an inner diameter of 4 mm.

[0024] like Figure 3 The diagram shows a deformation sensing and measurement module structure in which a single optical fiber is embedded in a laser-lithographically patterned flexible metal wire or a 3D-printed flexible high-elasticity grooved structure 9. The single-mode optical fiber 5 is embedded in a triangular groove 10 on the surface of the laser-lithographically patterned flexible metal wire or the 3D-printed flexible high-elasticity grooved structure 9. The grooves are distributed at 120° intervals on the circumference of the skeleton cross-section. The single optical fiber forms three equivalent "fiber cores" through this embedding method, constituting a spatially equivalent three-core optical fiber sensing structure. The precision processing of laser lithography or 3D printing ensures the uniformity and stability of the optical fiber distribution, improving the deformation detection accuracy.

[0025] The skeleton and fiber fixing structure of the deformation sensing measurement module are first prepared by manually fixing the optical fiber on the silicone tube. The processing accuracy of this method is relatively low compared with the laser engraving process, but it can quickly complete the sample preparation and realize the feasibility verification of the system and method of the present invention. In the future, the technical solution of the present invention can be further applied to high-precision measurement skeletons such as flexible metal wires with laser lithography grooves and 3D printed grooved flexible structures.

[0026] The following two specific embodiments verify the feasibility of applying the deformation sensing measurement module based on manually fixed optical fiber in the system of the present invention, involving four different packaging forms.

[0027] Example 2 A three-dimensional deformation reduction experiment was conducted using a silicone tube with optical fiber attached and employing the first encapsulation method. In this embodiment, the deformation sensing measurement module 4 uses a silicone tubing skeleton combined with the first encapsulation method. A 3mm silicone tubing is selected as the bending measurement skeleton 6, and the single-mode optical fiber 5 is attached axially to the outer surface of the bending measurement skeleton 6. The three equivalent "fiber cores" are distributed at 120° intervals on the circumference of the cross-section. A silicone tubing with an outer diameter of 5mm and an inner diameter of 4mm is selected as the silicone tubing 8. Flexible elastomer material PDMS7 (Dow Corning DC184, with a main agent to curing agent mass ratio of 10:1) is cast into the inner cavity of the silicone tubing 8, and then placed in an oven for constant temperature curing at 80°C for 2 hours to form a solid composite structure. This structure significantly improves the torsional resistance and optical fiber fixing reliability while maintaining flexibility.

[0028] The deformation sensing and measurement module 4, which has been prepared as described above, is connected to an optical frequency domain reflectometer (OFDR). The OFDR 3 has a spatial resolution of 2.6 mm, a measurement range of 100 m, and is equipped with distributed strain demodulation capabilities. The OFDR 3 injects probe light into the single-mode fiber 5 and acquires the backscattered Rayleigh signal in real time. The OFDR 3 can acquire distributed strain data of all three equivalent "fiber core" positions in a single scan in real time, without the need for beam splitters, optical couplers, or multiplexers for channel switching.

[0029] After receiving the distributed strain data demodulated by OFDR, signal processing unit 1 performs three-dimensional deformation reconstruction based on the Frenet-Serret framework. The specific algorithm flow is as follows: First, the curvature and bending direction at each section are calculated based on the strain values ​​at the three equivalent "fiber core" positions (the strain information of the second segment is reversed); then, the bending measurement skeleton 6 is discretized into several small arc segments, and the tangent direction, normal direction, and binormal direction of each discrete point are iteratively solved using the Frenet-Serret formula; finally, the three-dimensional spatial coordinates of the entire bending measurement skeleton 6 are obtained through integration, thus completing the shape restoration.

[0030] Example 3 A three-dimensional deformation reduction experiment was conducted using a silicone tube with optical fiber attached and a second encapsulation method. In this embodiment, the deformation sensing measurement module 4 uses a silicone tubing skeleton combined with a second encapsulation method. A 3mm silicone tubing is selected as the bending measurement skeleton 6. The single-mode optical fiber 5 is attached axially to the outer surface of the bending measurement skeleton 6. The three equivalent "fiber cores" are distributed at 120° intervals on the circumference of the cross-section. Multi-layer encapsulation is performed using multi-layer PDMS7: First, a first layer of PDMS7 is coated on the surface of the optical fiber and dried in an oven at 80°C for one hour. After the first layer has cured, a second layer of PDMS7 is coated, and this process is repeated four times to finally form a PDMS protective layer with a thickness of approximately 2.0mm. The deformation sensing measurement module 4 prepared above is then connected to an optical frequency domain reflectometer. Subsequent steps are the same as in Embodiment 1.

[0031] Example 4 A three-dimensional deformation reduction experiment using a silicone tube embedded with an optical fiber and employing the first encapsulation method; In this embodiment, the deformation sensing measurement module 4 adopts a first packaging form with embedded optical fiber and PDMS7 cast in the inner cavity. A 3mm silicone tubing is used as the bending measurement skeleton 6. Three grooves spaced 120° apart are processed on its outer surface using a precision mold or laser engraving. The single-mode optical fiber 5 is embedded in the grooves and temporarily fixed by drying PDMS7 in an oven at 80°C for one hour. A silicone tubing with an outer diameter of 5mm and an inner diameter of 4mm is used as the silicone tubing 8. The flexible elastomer material PDMS7 is cast into the inner cavity of the silicone tubing 8 and cured at 80°C for 2 hours in an oven to form a solid composite structure. The deformation sensing measurement module 4 prepared above is connected to the optical frequency domain reflectometer. The subsequent steps are the same as in Embodiment 1 and will not be repeated here.

[0032] Example 5 A three-dimensional deformation reduction experiment using a silicone tube embedded with an optical fiber and employing a second encapsulation method; In this embodiment, the deformation sensing measurement module 4 adopts a first encapsulation form with embedded optical fiber and PDMS cast in the inner cavity. A 3mm silicone tube is used as the bending measurement skeleton 6. Three grooves spaced 120° apart are processed on its outer surface using a mold or laser engraving. The single-mode optical fiber 5 is embedded in the grooves and temporarily fixed by drying it in an oven at 80°C for one hour using PDMS7. Multi-layer encapsulation is performed using multi-layer PDMS7: first, a first layer of PDMS7 is coated on the surface of the optical fiber and dried in an oven at 80°C for one hour; after the first layer has cured, a second layer of PDMS7 is coated, and this process is repeated 4 times to finally form a PDMS protective layer with a thickness of about 2.0mm. The deformation sensing measurement module 4 prepared above is connected to an optical frequency domain reflectometer. Subsequent steps are the same as in Embodiment 1.

[0033] Example 6 Verification of two-dimensional / three-dimensional bending deformation based on simulated strain data; This embodiment is used to verify the three-dimensional deformation reconstruction capability of the system and method of the present invention under known bending morphology. The simulation model has a total length of 50mm, with three equivalent "fiber cores" distributed along the axial direction. Their cross-sectional distribution is consistent with the previous embodiment, with the cores spaced 120° apart on the circumference, and the fiber cores are 0.8mm away from the center of the whole.

[0034] During the simulation, uniaxial bending strain and three-dimensional bending strain were constructed respectively, and bending strain data of three equivalent "fiber cores" along the length direction were exported. The strain data were then input into signal processing unit 1, and curvature, bending direction, and integral were solved based on the Frenet-Serret framework to complete the shape reconstruction. Figure 4 As shown, under the uniaxial bending strain simulation condition, after restoring the original curve using strain data, the obtained curve basically coincides with the original simulation curve, as shown in the three views. Figure 5 (a) Figure 5 (b) andFigure 5 As shown in (c), the XY plane projection accurately reflects the two-dimensional curved profile, and the projection lengths of both the XZ and YZ planes also match the actual projection lengths. Figure 6 As shown, under the three-dimensional bending simulation condition, the spatial curve obtained after the strain information is integrated and restored using the Frenet-Serret framework is basically consistent with the simulation theoretical curve. The corresponding XY plane, XZ plane, and YZ plane projections all have a high degree of overlap, as shown in the figure. Figure 7 (a) Figure 7 (b) and Figure 7 As shown in (c), the two simulation reconstruction results demonstrate that the method of the present invention can effectively reconstruct the spatial morphology under actual bending conditions.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A simplified three-dimensional deformation restoration system based on single-mode optical fiber, characterized in that, include: Light source, optical frequency domain reflectometer, deformation sensing measurement module and signal processing unit; The light source is connected to the input terminal of the optical frequency domain reflectometer to provide detection light for the entire system; The output end of the optical frequency domain reflectometer is connected to the input end of the single-mode fiber to inject probe light into the single-mode fiber and receive backscattered Rayleigh signals, thereby detecting and demodulating the distributed strain generated at the three equivalent "core" positions in the single-mode fiber in real time. The input end of the deformation sensing measurement module is connected to the output end of the optical frequency domain reflectometer. When subjected to bending deformation, it causes the three equivalent "core" segments of the single-mode fiber to be stretched or compressed, and reflects the backscattered Rayleigh signal back to the optical frequency domain reflectometer. The signal processing unit is connected to the optical frequency domain reflectometer to receive signals and, based on the Frenet-Serret framework, calculate and reconstruct the three-dimensional spatial shape of the bending measurement skeleton according to the distributed strain data at three equivalent "core" locations.

2. The simplified three-dimensional deformation restoration system based on single-mode optical fiber according to claim 1, characterized in that, The deformation sensing measurement module consists of a bending measurement frame, a single-mode optical fiber, and encapsulation materials.

3. The simplified three-dimensional deformation restoration system based on single-mode optical fiber according to claim 2, characterized in that, The bending measurement frame can be any one of the following: a silicone hose, a flexible metal wire with laser-etched grooves, or a grooved structure directly printed from a flexible, highly elastic material using a 3D printer.

4. The simplified three-dimensional deformation restoration system based on single-mode optical fiber according to claim 5, characterized in that, If a thicker optical cable is used instead of a single-mode optical fiber in a large-scale application scenario, a bending measurement skeleton is not used. Instead, an optical cable is directly folded into three sections and bound together in a three-section manner. The three sections are equivalent to a three-core optical fiber. In this case, the deformation sensing measurement module is directly composed of a thicker optical cable and encapsulation material.

5. The simplified three-dimensional deformation restoration system based on single-mode optical fiber according to claim 4, characterized in that, The single-mode fiber is attached or embedded along the axial direction to the surface of the bending measurement skeleton, and is distributed in a triangular pattern at 120° intervals on the circumference of the cross-section of the bending measurement skeleton, forming a spatially equivalent three-core fiber sensing structure; the grooves on the surface of the flexible metal wire are grooved flexible structures processed by laser lithography and printed by 3D printer, each with three triangular grooves at 120° intervals embedded in them, and the single-mode fiber is embedded in the grooves, fixed and encapsulated.

6. The simplified three-dimensional deformation restoration system based on single-mode optical fiber according to claim 5, characterized in that, The bending measurement frame is made of material with a diameter of 1-3mm. The flexible elastomer material for fixing the optical fiber is PDMS. The encapsulation body is a silicone tube or PDMS with an outer diameter of 5mm and an inner diameter of 4mm.

7. The simplified three-dimensional deformation restoration system based on single-mode optical fiber according to claim 6, characterized in that, The optical frequency domain reflectometer acquires distributed strain data for all three equivalent "fiber core" locations in one operation.

8. The simplified three-dimensional deformation restoration system based on single-mode optical fiber according to claim 7, characterized in that, The packaging forms of the deformation sensing measurement module include at least two types: Form 1: A hollow silicone tube is used as the encapsulation body, PDMS is poured into its inner cavity, and a solid composite structure is formed after being heated and cured in an oven. Form 2: After attaching or embedding a single-mode optical fiber into the bending measurement skeleton, multi-layer PDMS is used for multi-layer encapsulation. After each layer is coated, it is placed in an oven to dry, and this process is repeated multiple times to form a protective layer.

9. A simplified three-dimensional deformation reduction method based on single-mode optical fiber, using a simplified three-dimensional deformation reduction system based on single-mode optical fiber as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. After encapsulating the bending measurement skeletons of different thicknesses with attached or embedded single-mode optical fibers using different encapsulation methods, place them in the test environment to cause bending deformation. S2. Using a light source, the optical frequency domain reflectometer is injected with probe light into a single-mode fiber to collect backscattered Rayleigh signals and obtain distributed strain data. S3. Demodulate the strain changes from the distributed strain data to the three equivalent "core" positions on the circumference of the bending measurement skeleton cross section, which are 120° apart. S4. Based on the Frenet-Serret framework, the three-dimensional spatial shape of the bending measurement skeleton is iteratively calculated and restored using strain change data at three equivalent "core" locations.

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