Optical fiber tactile sensing structure with self-adjustable measuring range and manufacturing process of optical fiber tactile sensing structure

Abstract

The invention relates to the technical field of optical fiber pressure sensors, in particular to a measuring range self-adjusting optical fiber touch sensing structure and a manufacturing process. The pressure sensor structurally comprises a first optical fiber pressure sensing part and a second optical fiber pressure sensing part which are different in measuring range, the first optical fiber pressure sensing part comprises a contact part, an elastic buffering part is arranged on the lower side of the contact part, an optical fiber flexible sensing part is arranged on the lower side of the elastic buffering part, and the elastic buffering part and the optical fiber flexible sensing part are arranged in a containing cavity with an opening in the top. A limiting table is arranged on the upper side of the containing cavity, when the elastic buffering part contracts, the bottom of the contact part is in rigid contact with the limiting table, and the containing cavity is connected with the measuring end of the optical fiber second pressure sensing part. The first optical fiber pressure sensing part and the second optical fiber pressure sensing part with different measuring ranges are combined through the elastic buffer part, so that the flexibility is maintained, and meanwhile, the force measurement range is wider.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber pressure sensors, and in particular to an optical fiber tactile sensing structure with self-adjusting range and a manufacturing process. Background Art

[0002] The emergence of Industry 4.0 has introduced new concepts to factories, requiring further optimization and improvement of traditional processes. Industrial robots are enabled to perform tasks faster and more accurately. Using tactile sensors to improve the proprioception and tactile sensitivity of robots is an effective way to achieve these goals. Tactile perception is essential for delicate manipulation tasks and extracting key physical features in soft fixtures. Traditional tactile sensors are devices based on mechanical or electrical principles. The main principle is to arrange strain gauges on metal elastic elements, and when the interaction force is applied to the metal elastic element, the strain gauge changes accordingly. However, electronic strain gauges have disadvantages such as low sensitivity, easy drift, and easy electromagnetic interference.

[0003] A dual fiber Bragg grating soil pressure sensor with publication number CN206514980U specifically includes a sensor housing, a parallelogram sensor, a sensing fiber Bragg grating, a temperature compensation fiber Bragg grating, and necessary components and external parts. It uses two fiber Bragg gratings stretched on the two diagonals of the parallelogram sensor. Through dual fiber Bragg gratings, one is a sensing fiber Bragg grating and the other is a temperature compensation fiber Bragg grating, it can compensate for the error caused by temperature. Although the use of fiber Bragg grating gives it a certain anti-interference ability and can improve the measurement accuracy to a certain extent, its measurement range is limited and it is difficult to meet the accuracy requirements of large-scale measurements. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a fiber optic tactile sensing structure with self-adjusting range in response to the above-mentioned technical deficiencies. The structure adopts a fiber optic first pressure sensing part and a fiber optic second pressure sensing part with two different ranges, which are combined through an elastic buffer part. While maintaining flexibility, the structure has a wider force measurement range, which solves the problem that the existing structure has a limited measurement range and is difficult to adapt to the accuracy requirements of large-range measurements.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a fiber optic tactile sensing structure with self-adjusting range, comprising a first fiber optic pressure sensing part and a second fiber optic pressure sensing part with different ranges, the first fiber optic pressure sensing part comprising a contact part, an elastic buffer part is provided on the lower side of the contact part, a fiber optic flexible sensing part is provided on the lower side of the elastic buffer part, the elastic buffer part and the fiber optic flexible sensing part are arranged in a cavity with a top opening, a limit platform is provided on the upper side of the cavity, when the elastic buffer part contracts, the bottom of the contact part is rigidly contacted with the limit platform, and the cavity is connected to the measuring end of the second fiber optic pressure sensing part.

[0006] To further optimize the technical solution, the second pressure sensing portion of the optical fiber is a frame structure surrounded by a polygon, and the first optical fiber Bragg grating and the second optical fiber Bragg grating that cross each other are pulled inside the frame structure. The first optical fiber Bragg grating and the second optical fiber Bragg grating are communicatively connected with the optical fiber modulator.

[0007] To further optimize the technical solution, the frame structure is a quadrilateral structure with four rigid beams connected end to end, the bottom beam of the quadrilateral structure is fixed, a top beam is provided at the upper part of the quadrilateral structure opposite to the bottom beam, the first fiber grating and the second fiber grating are cross-connected at both ends of the top beam and the bottom beam, and the top beam constitutes the measuring end of the second pressure sensing part of the optical fiber.

[0008] To further optimize the technical solution, the frame structure is an octagonal structure, the bottom side of the octagonal structure is fixed, a top side beam is provided on the top of the octagonal structure, the top side beam and the bottom side are arranged opposite to each other, the first fiber grating is connected between the top side beam and the bottom side, the second fiber grating is connected between the two opposite sides of the octagonal structure, and the second fiber grating is arranged vertically and crosswise with the first fiber grating.

[0009] To further optimize the technical solution, the optical fiber flexible sensing portion is an optical fiber Fabry-Perot sensor, a flexible silicone layer is provided on the outside of the optical fiber flexible sensing portion, and a sensing optical fiber is radially penetrated in the flexible silicone layer.

[0010] To further optimize the technical solution, the optical fiber flexible sensing portion is an optical fiber Mach-Zehnder sensor, a silicone layer is provided on the outside of the optical fiber flexible sensing portion, an optical fiber sensor is provided in the silicone layer, the optical fiber sensor is a single-mode optical fiber, a grating portion and a seven-core optical fiber portion are provided in the single-mode optical fiber, coreless optical fibers are provided at both ends of the seven-core optical fiber portion, the seven-core optical fiber portion is connected to the single-mode optical fiber through the coreless optical fibers provided at both ends, the length of the seven-core optical fiber portion is 20 mm, and the length of the coreless optical fiber is 1 mm.

[0011] The present invention also provides a process for manufacturing a fiber optic tactile sensing structure with self-adjustable range, including the manufacturing of a first pressure sensing portion of the fiber optic and the manufacturing of a second pressure sensing portion of the fiber optic;

[0012] When making the first pressure sensing part, first make a cylindrical mold with an inner diameter of 50 mm and a thickness of 5 mm. There are grooves with a diameter of 0.5 mm on both sides of the radial direction of the mold for placing the optical fiber sensor.

[0013] When encapsulating the flexible sensor, first pass the prepared optical fiber sensor through the grooves on both sides of the mold, adjust the position of the optical fiber sensor so that it is placed in the middle of the mold, and use the optical fiber clamp to apply a certain pre-tightening force to both ends of the optical fiber sensor to keep the optical fiber sensor in a stretched state; then pour in silicone, pour Ecoflex into the mold at a ratio of A:B=1:1, and cure the silicone at 60°C for 30 minutes. After curing, remove the mold to obtain a silicone-encapsulated flexible sensor with a measurement sensitivity of 5nm / N;

[0014] When making the second pressure sensing portion of the optical fiber, a fixing hole needs to be set in the frame structure first to fix the first optical fiber Bragg grating and the second optical fiber Bragg grating. When installing the first optical fiber Bragg grating and the second optical fiber Bragg grating, it is necessary to ensure that the first optical fiber Bragg grating and the second optical fiber Bragg grating have a certain pre-tightening force in the frame structure, and then use epoxy resin glue to fix the two ends of the optical fiber to the frame structure respectively;

[0015] The contact part is coated with polylactic acid material and the outer coating is made of rubber material to increase the friction coefficient of the contact surface.

[0016] Compared with the prior art, the present invention has the following advantages: 1. A novel self-adjustable fiber optic tactile sensing structure is proposed, which combines two fiber optic first pressure sensing parts and fiber optic second pressure sensing parts of different ranges through an elastic buffer part, thereby maintaining flexibility while having a wider force measurement range; 2. The fiber optic second pressure sensing part of the frame structure can achieve temperature compensation while measuring the contact force through the cooperation of the first fiber optic grating and the second fiber optic grating that cross each other; 3. The structure of the present invention is compact and flexible, and is suitable for use in harsh environments such as strong electromagnetic interference and humidity; 4. Compared with the tactile sensing technology based on electrical principles, optical touch, especially the tactile sensing technology based on optical fiber, has the advantages of anti-electromagnetic interference, high sensitivity, easy multiplexing, small size, light weight, high temperature resistance, corrosion resistance, etc., and is suitable for harsh environments such as strong electromagnetic interference, flammable and explosive, and humidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the principle of a first embodiment of a self-adjustable optical fiber tactile sensing structure;

[0018] Figure 2 The changes of the structure in the first embodiment after being subjected to stress;

[0019] Figure 3 is a schematic structural diagram of the optical fiber Fabry-Perot sensor structure in Example 1;

[0020] Figure 4 This is a schematic diagram of the structure of a sensing node in a sensing optical fiber according to Embodiment 1;

[0021] Figure 5 This is a working principle diagram of a sensing node in a sensing optical fiber in Example 1;

[0022] Figure 6 It is a structural schematic diagram of a second embodiment of a self-adjustable optical fiber tactile sensing structure;

[0023] Figure 7 Schematic diagram of the structure of the optical fiber sensor part in the optical fiber Mach-Zehnder sensor in the second embodiment.

[0024] In the figure: 1, contact part; 2, elastic buffer part; 3, optical fiber flexible sensing part; 30, flexible silicone layer; 31, sensing optical fiber; 311, single-mode optical fiber; 32, grating part; 33, seven-core optical fiber part; 34, coreless optical fiber; 4, cavity; 41, limit table; 5, top beam; 51, first optical fiber grating; 52, second optical fiber grating; 6, top side beam; 60, bottom side. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the reference drawings of specific embodiments. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0026] Unless otherwise defined, the technical or scientific terms used herein shall have the common meanings understood by persons having ordinary skills in the field to which the present invention belongs. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] Embodiment 1

[0028] Combination Figures 1 to 3 As shown, a fiber optic tactile sensing structure with self-adjustable range includes a first fiber optic pressure sensing portion and a second fiber optic pressure sensing portion with different ranges.

[0029] The first pressure sensing part of the optical fiber includes a contact part 1, and an elastic buffer part 2 is provided on the lower side of the contact part 1. The elastic buffer part 2 of this embodiment is a columnar spring, and an optical fiber flexible sensing part 3 is provided on the lower side of the elastic buffer part 2. In this embodiment, the optical fiber flexible sensing part 3 is an optical fiber Fabry-Perot sensor, and a flexible silicone layer 30 is provided on the outside of the optical fiber flexible sensing part 3, and a sensing optical fiber 31 is radially penetrated in the flexible silicone layer 30. Figures 4 to 5As shown, a first reflection surface M1 and a second reflection surface M2 are provided at the sensing node in the sensing optical fiber 31. The first reflection surface M1 is the fusion surface of the single-mode optical fiber and the hollow-core optical fiber, and the second reflection surface M2 is the fusion surface of the hollow-core optical fiber and the right single-mode optical fiber.

[0030] During use, the sensing optical fiber 31 is connected to the demodulator, and the demodulator has a broadband light source (C+L band) and a photodetector inside. When the optical fiber flexible sensing part 3 is in use, after the broadband light inside the demodulator is incident on the single-mode optical fiber (SMF), the light beam first reaches the first reflection surface M1, and a reflected light is formed at the first reflection surface M1, and the intensity of the reflected light is I1. Part of the light passes through the first reflection surface M1 and continues to propagate to the second reflection surface M2, and part of the light beam is reflected back to the first reflection surface M1, forming a reflected light with an intensity of I2. Due to the different optical path differences of the two lights, interference occurs between the reflected lights I1 and I2.

[0031] The intensity of the interference light is as shown in formula 1:

[0032] Formula 1:

[0033] Where φ0 is the initial phase difference between I1 and I2, φ is the relative phase difference, and the relative phase difference formula is as follows:

[0034] Formula 2:

[0035] Where, δ is the optical path difference, δ=2(nL), n is the refractive index of air, L is the length between the two reflecting surfaces, and λ is the wavelength of the light transmitted in the FP cavity.

[0036] The elastic buffer part 2 and the optical fiber flexible sensing part 3 are arranged in a cavity 4 with an opening at the top. The cavity 4 is a rigid cylinder. A limit platform 41 is provided on the upper side of the cavity 4. When the elastic buffer part 2 contracts, the bottom of the contact part 1 is rigidly contacted with the limit platform 41, and the cavity 4 is connected to the measuring end of the second pressure sensing part of the optical fiber.

[0037] The optical fiber second pressure sensing part is a frame structure surrounded by a polygon, and the frame structure has a first optical fiber grating 51 and a second optical fiber grating 52 intersecting with each other pulled inside. The first optical fiber grating 51 and the second optical fiber grating 52 are communicatively connected with the optical fiber modulator.

[0038] In this embodiment, the frame structure is a quadrilateral structure with four rigid beams connected end to end. The bottom beam 50 of the quadrilateral structure is fixedly arranged, and a top beam 5 is provided at the upper part of the quadrilateral structure opposite to the bottom beam 50. The first fiber grating 51 and the second fiber grating 52 are cross-connected at both ends of the top beam 5 and the bottom beam 50, and the top beam 5 constitutes the measuring end of the second pressure sensing part of the optical fiber.

[0039] When in use, the external force to be measured is first applied to the upper part of the contact part 1, and the elastic buffer part 2 is compressed at the same time, and the force of the contact part 1 is transmitted to the optical fiber flexible sensing part 3, that is, the optical fiber Fabry-Perot sensor in this embodiment is triggered, and the optical fiber Fabry-Perot sensor is connected to the demodulator. At this time, the optical fiber Fabry-Perot sensor cooperates with the demodulator to convert the output light signal change into the change of the electrical signal. When the external pressure acts on the flexible silicone layer 30, the flexible silicone layer is deformed, causing the sensing optical fiber 31 embedded therein to be deformed. This causes the distance L between the two reflection surfaces of the optical fiber Fabry-Perot sensor to change, and the optical path difference between the two reflected lights changes, thereby causing the interference fringes to change. The specific value of the external pressure is calculated by using relevant algorithms and calculation methods. As the external pressure increases, the bottom of the contact part 1 directly contacts the limit table 41 rigidly. Finally, the contact part 1 contacts the top beam 5 rigidly through the limit table 41 and the cavity 4. The contact part 1 directly transmits the received force to the top beam 5 of the second pressure sensing part of the optical fiber. At this time, the quadrilateral structure undergoes elastic deformation, the longer first optical fiber grating 51 is subjected to tensile strain, and the shorter second optical fiber grating 52 is subjected to compressive strain. According to the wavelength change of the optical signal transmitted by the first optical fiber grating 51 and the second optical fiber grating 52, the magnitude of the force can be calculated. This structure can also eliminate the influence of temperature fluctuations. The Fabry-Perot sensor used in this embodiment can realize single-end measurement, that is, the input signal and the output signal are realized through one optical fiber. The length of the Fabry-Perot sensor is short, ranging from tens to hundreds of microns; precise cutting equipment is required when making the Fabry-Perot sensor.

[0040] Embodiment 2

[0041] Combination Figures 4 to 5 As shown, a self-adjustable fiber optic tactile sensing structure includes a first fiber optic pressure sensing portion and a second fiber optic pressure sensing portion with different ranges. Different from the first embodiment, the frame structure in the second fiber optic pressure sensing portion is an octagonal frame structure, the bottom side 60 of the octagonal structure is fixedly arranged, and a top side beam 6 is arranged on the top of the octagonal structure, and the top side beam 6 is arranged opposite to and parallel to the bottom side 60, the second fiber grating 52 is connected between the top side beam 6 and the bottom side 60, the first fiber grating 51 is connected between the two opposite sides of the octagonal structure, and the second fiber grating 52 is arranged vertically and crosswise with the first fiber grating 51.

[0042] In this embodiment, the optical fiber flexible sensing part 3 is an optical fiber Mach-Zehnder sensor. A silicone layer is provided on the outer side of the optical fiber flexible sensing part 3. An optical fiber sensor is provided in the silicone layer. A single-mode optical fiber 311 is provided in the optical fiber sensor. A grating part 32 and a seven-core optical fiber part 33 are provided in the single-mode optical fiber 311. A coreless optical fiber 34 is provided at each end of the seven-core optical fiber part 33. The seven-core optical fiber part 33 is connected to the single-mode optical fiber 311 through the coreless optical fiber 34 provided at both ends. The length of the seven-core optical fiber part 33 is 20 mm, and the length of the coreless optical fiber 34 is 1 mm. A light source is provided on one side of the optical fiber Mach-Zehnder sensor, and a light detector is provided on the other side.

[0043] When in use, the external force to be measured is first applied to the upper part of the contact part 1, and the elastic buffer part 2 is compressed at the same time, and the force of the contact part 1 is transmitted to the optical fiber flexible sensing part 3, that is, the optical fiber Mach-Zehnder sensor in this embodiment is triggered. At this time, in conjunction with the light source and the light detector, the light detector detects the change information of the interference fringes when the light wave is transmitted, converts it into an electrical signal, and inputs it into an appropriate data processing system. The data processing system is used to calculate the drift of the interference wavelength and then the activity pressure information.

[0044] By demodulating and analyzing these electrical signals, the changes in the external measured parameters can be inferred, thereby obtaining the measurement results. As the external pressure increases, the bottom of the contact part 1 directly and rigidly contacts the limit table 41, and the contact part 1 directly transmits the received force to the top edge beam 6 of the second pressure sensing part of the optical fiber. At this time, the octagonal structure undergoes elastic deformation, the first optical fiber grating 51 is subjected to tensile strain, and the second optical fiber grating 52 is subjected to compressive strain. According to the change in the wavelength of the optical signal transmitted by the first optical fiber grating 51 and the second optical fiber grating 52, the magnitude of the force can be calculated.

[0045] This structure can also eliminate the influence of temperature fluctuations. When the top side beam 6 is deformed, the first fiber grating 51 is subjected to tensile strain, and the second fiber grating 52 is subjected to compressive strain. The wavelength changes measured by the first fiber grating 51 and the second fiber grating 52 are Δλ respectively. 51 and Δλ 52 The wavelength change is also affected by temperature and strain as follows:

[0046] Formula 3: Δλ 51 =ΔT 51 +Δε 51

[0047] Formula 4: Δλ 52 =ΔT52+Δε 52

[0048] Due to the temperature change ΔT 51 and ΔT 52are equal, subtracting formula 4 from formula 3 gives formula 5:

[0049] Formula 5: Δλ 51 -Δλ 52 =Δε 51 -Δε 52

[0050] It can be seen from Formula 5 that the wavelength change is only affected by the strain change, eliminating the influence of temperature T.

[0051] The Mach-Zehnder sensor used in this embodiment needs to have single-mode optical fibers at both ends, that is, one side of the optical fiber is used for inputting signals, and the other side of the optical fiber is used for collecting signals. The length of the Mach-Zehnder sensor is usually 10 to 20 mm, so the Mach-Zehnder sensor is easier to manufacture than the Fabry-Perot sensor, does not require precise cutting, and is easy to prepare.

[0052] Embodiment 3

[0053] A process for manufacturing a self-adjustable optical fiber tactile sensing structure, including the manufacturing of the first pressure sensing portion of the optical fiber and the manufacturing of the second pressure sensing portion of the optical fiber in the second embodiment;

[0054] When making the first pressure sensing part, first make the optical fiber sensor in the optical fiber Mach-Zehnder sensor, and use an optical fiber fusion splicer to fuse a section of a 20mm long seven-core optical fiber section 33 with a coreless optical fiber 34 at both ends. Use an optical fiber cutter to cut the fused coreless optical fiber 34 to 1mm; then, the seven-core optical fiber section 33 with 1mm coreless optical fiber 34 on both sides is fused with a single-mode optical fiber 311, and a section of the single-mode optical fiber 311 is engraved with a grating section 32 for temperature compensation. The optical fiber Mach-Zehnder sensor can be obtained.

[0055] Next, a cylindrical mold is made, which can be made using 3D printing technology. The inner diameter of the mold is 50 mm and the thickness is 5 mm. There are grooves with a diameter of 0.5 mm on both radial sides of the mold for placing optical fiber sensors.

[0056] When packaging the flexible sensor, first pass the prepared optical fiber sensor through the grooves on both sides of the mold, adjust the position of the optical fiber sensor so that it is placed in the middle of the mold, and use the optical fiber clamp to apply a certain pre-tightening force to both ends of the optical fiber sensor to keep the optical fiber sensor in a stretched state; then pour in silicone, pour Ecoflex 0050 into the mold at a ratio of A:B=1:1, and cure the silicone at 60°C for 30 minutes. After curing, remove the mold to obtain the silicone-encapsulated flexible sensor 3. The measurement sensitivity of the flexible sensor 3 is 5nm / N.

[0057] The contact part 1 is made of polylactic acid material, and the outer coating is made of rubber material to increase the friction coefficient of the contact surface.

[0058] During assembly, the optical fiber Mach-Zehnder sensor is placed at the bottom of the limiting mechanism, and then the elastic buffer part 2 is installed on it, and the contact part 1 is installed on the elastic buffer part 2.

[0059] When making the second pressure sensing part of the optical fiber, the elastic beam of the octagonal structure is prepared by 3D printing technology. Different sizes can be designed as needed. At the same time, it is necessary to first set a fixing hole in the frame structure to fix the first optical fiber grating 51 and the second optical fiber grating 52. When the first optical fiber grating 51 and the second optical fiber grating 52 are installed, it is necessary to ensure that the first optical fiber grating 51 and the second optical fiber grating 52 have a certain pre-tightening force in the frame structure, and then use epoxy resin glue to fix the two ends of the optical fiber to the frame structure respectively. The epoxy resin glue is cured at 80°C for half an hour to complete the curing.

[0060] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A fiber optic tactile sensing structure with self-adjustable range, characterized in that: The invention comprises a first optical fiber pressure sensing part and a second optical fiber pressure sensing part with different measuring ranges, wherein the first optical fiber pressure sensing part comprises a contact part (1), an elastic buffer part (2) is provided on the lower side of the contact part (1), an optical fiber flexible sensing part (3) is provided on the lower side of the elastic buffer part (2), the elastic buffer part (2) and the optical fiber flexible sensing part (3) are arranged in a cavity (4) with a top opening, a limiting platform (41) is provided on the upper side of the cavity (4), when the elastic buffer part (2) contracts, the bottom of the contact part (1) is rigidly contacted with the limiting platform (41), and the cavity (4) is connected to the measuring end of the second optical fiber pressure sensing part.

2. The optical fiber tactile sensing structure with self-adjustable range according to claim 1, characterized in that: The optical fiber second pressure sensing portion is a frame structure surrounded by a polygon, and a first optical fiber grating (51) and a second optical fiber grating (52) that cross each other are pulled inside the frame structure. The first optical fiber grating (51) and the second optical fiber grating (52) are communicatively connected to the optical fiber modulator.

3. The optical fiber tactile sensing structure with self-adjustable range according to claim 2, characterized in that: The frame structure is a quadrilateral structure with four rigid beams connected end to end, the bottom beam (50) of the quadrilateral structure is fixedly arranged, a top beam (5) is arranged at the upper part of the quadrilateral structure opposite to the bottom beam (50), the first optical fiber grating (51) and the second optical fiber grating (52) are cross-connected at both ends of the top beam (5) and the bottom beam (50), and the top beam (5) constitutes the measuring end of the second pressure sensing part of the optical fiber.

4. The optical fiber tactile sensing structure with self-adjustable range according to claim 2, characterized in that: The frame structure is an octagonal structure, the bottom side (60) of the octagonal structure is fixedly arranged, a top side beam (6) is arranged on the top of the octagonal structure, the top side beam (6) is arranged opposite to the bottom side (60), the first fiber grating (51) is connected between the top side beam (6) and the bottom side (60), the second fiber grating (52) is connected between two opposite sides of the octagonal structure, and the second fiber grating (52) and the first fiber grating (51) are arranged crosswise and perpendicularly.

5. The optical fiber tactile sensing structure with self-adjustable range according to claim 1, characterized in that: The optical fiber flexible sensing part (3) is an optical fiber Fabry-Perot sensor. A flexible silicone layer (30) is provided on the outside of the optical fiber flexible sensing part (3), and a sensing optical fiber (31) is radially penetrated in the flexible silicone layer (30).

6. The optical fiber tactile sensing structure with self-adjustable range according to claim 1, characterized in that: The optical fiber flexible sensing part (3) is an optical fiber Mach-Zehnder sensor. A silicone layer is provided on the outer side of the optical fiber flexible sensing part (3). An optical fiber sensor is provided in the silicone layer. The optical fiber sensor is a single-mode optical fiber (311). A grating part (32) and a seven-core optical fiber part (33) are provided in the single-mode optical fiber (311). Coreless optical fibers (34) are provided at both ends of the seven-core optical fiber part (33). The seven-core optical fiber part (33) is connected to the single-mode optical fiber (311) via the coreless optical fibers (34) provided at both ends. The length of the seven-core optical fiber part (33) is 20 mm, and the length of the coreless optical fiber (34) is 1 mm.

7. A process for manufacturing a fiber optic tactile sensing structure with self-adjustable range, characterized in that: The manufacturing of the first pressure sensing portion of the optical fiber and the manufacturing of the second pressure sensing portion of the optical fiber in claim 5 above; When making the first pressure sensing part, first make a cylindrical mold with an inner diameter of 50 mm and a thickness of 5 mm. There are grooves with a diameter of 0.5 mm on both radial sides of the mold for placing the optical fiber sensor (31); When the flexible sensor is packaged, the prepared optical fiber sensor (31) is first passed through the grooves on both sides of the mold, the position of the optical fiber sensor (31) is adjusted so that it is placed in the middle of the mold, and a certain pre-tightening force is applied to both ends of the optical fiber sensor (31) using an optical fiber clamp to keep the optical fiber sensor (31) in a stretched state; then, silicone is poured in, and Ecoflex 0050 is poured into the mold at a ratio of A:B=1:1, and the silicone is cured at a temperature of 60°C for 30 minutes. After the curing is completed, the mold is removed to obtain a flexible sensor (3) packaged with silicone, and the measurement sensitivity of the flexible sensor (3) is 5nm / N; When manufacturing the second pressure sensing portion of the optical fiber, a fixing hole must be firstly provided in the frame structure for fixing the first optical fiber grating (51) and the second optical fiber grating (52). When the first optical fiber grating (51) and the second optical fiber grating (52) are installed, it must be ensured that the first optical fiber grating (51) and the second optical fiber grating (52) have a certain pre-tightening force in the frame structure, and then epoxy resin glue is used to fix the two ends of the optical fiber to the frame structure respectively; The contact part (1) is made of polylactic acid material, and the outer coating is made of rubber material to increase the friction coefficient of the contact surface.

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