Fbg micro force sensor

Abstract

The application discloses a FBG micro force sensor and belongs to the technical field of force sensors. The FBG micro force sensor comprises a sensor body, a first single FBG optical fiber and a second single FBG optical fiber. A pressure beam area and a shear beam area are arranged on the sensor body, and a plurality of independent single FBG optical fibers are fixedly arranged on the outer wall of the sensor body and correspond to the pressure beam area and the shear beam area. The single FBG partition compression structure length is utilized, the sensor can realize three-dimensional force sensing, the rigid section length of the sensor can be effectively shortened, the overall length of the sensor is shortened, the flexible endoscope tip integrated with the sensor can maintain a bending capacity of more than 90 degrees, and through special notch design, the axial sensitivity is ensured, the maximum bending deformation is limited, and overloading is prevented. The technical problem that end force sensing, instrument function integrity, high bending freedom and anti-overload reliability are difficult to be compatible in maxillary sinus surgery is solved.

Description

Technical Field

[0001] This invention belongs to the field of force sensor technology, specifically relating to an FBG miniature force sensor. Background Technology

[0002] Flexible endoscopes are widely used in complex minimally invasive surgeries such as those involving narrow maxillary sinuses due to their excellent accessibility and visualization. However, the lack of real-time, precise end-effector force sensing has been a significant factor limiting the safety and accuracy of endoscopic-assisted surgery. Existing force sensing technology based on fiber Bragg gratings (FBGs) shows promising application prospects in minimally invasive surgery due to its advantages such as small size, resistance to electromagnetic interference, and high sensitivity; however, significant technical bottlenecks remain in its integration into the endoscope's tip. Specifically, existing FBG sensors generally suffer from the following two core problems: First, existing built-in FBG sensors occupy the core cross-section of the endoscope's working channel or instrument channel, forcing key functional components such as the surgical field transmission fiber optic cable or instrument operating lever to be unable to be deployed at the end simultaneously. This severely restricts the integrated instrument-sensor-imaging system, forcing doctors to compromise between force feedback and instrument function / field clarity when operating in narrow spaces (such as the maxillary sinus). Second, common dual FBG sensors typically use a dual-grid arrangement on the same fiber. Because a certain distance must be maintained between the two grids to avoid crosstalk, the rigid section of the sensor is relatively long. After being integrated into the end of a flexible endoscope, this rigid section forms an ineffective working area when bent, severely reducing the bending freedom of the endoscope body and making it difficult to adapt to the multi-angle exploration and fine operation needs of areas with complex anatomical structures and extremely limited space, such as the maxillary sinus.

[0003] Furthermore, existing sensor structural materials (such as stainless steel or certain engineering plastics) are prone to plastic deformation or brittle fracture under repeated loading or accidental overload during minimally invasive surgery. Once they fail, not only is the sensing function lost, but residual fragments may also cause secondary tissue damage. Meanwhile, the long-term biocompatibility and performance stability in bodily fluid environments of some polymer materials are questionable, making it difficult to meet the requirements for direct contact or long-term implantation with minimally invasive surgical instruments. Therefore, current technology urgently needs a miniaturized, highly flexible, and highly reliable FBG force sensor solution that can simultaneously address issues such as channel occupancy, excessively long rigid sections, weak overload resistance, and biocompatibility requirements, to achieve seamless, safe, and high-performance integration at the tip of a flexible endoscope in confined spaces. Summary of the Invention

[0004] In response to one or more of the above-mentioned defects or improvement needs of the prior art, the present invention provides an FBG miniature force sensor that can achieve miniaturized integration and overload protection of the flexible endoscope end-effector sensing module while maintaining a compact structure and measurement accuracy. This solves the problems of "difficulty in integration" and "limited flexibility" of traditional FBG sensors in narrow surgical spaces.

[0005] To achieve the above objectives, the present invention provides an FBG miniature force sensor, which includes a sensor body, a first single FBG optical fiber, and a second single FBG optical fiber.

[0006] The sensor body is a hyperelastic tubular structure, including a pressure beam area and a shear beam area arranged sequentially along the axial direction;

[0007] The pressure beam region is used to sense axial pressure and includes a first connecting beam, a first annular short beam, a second connecting beam, and a second annular short beam. Two first connecting beams and two second connecting beams are symmetrically arranged along the axis of the sensor body, with a first notch between each side of the two first connecting beams and a second notch between each side of the two second connecting beams. One axial end of the first annular short beam is connected to the first connecting beam, and the other end is connected to the second connecting beam. The other end of the second connecting beam is connected to the second annular short beam, which is connected to the shear beam region.

[0008] The shear beam zone is used to sense lateral shear force and includes multiple shear beams spaced apart circumferentially, which are connected to the second annular short beam;

[0009] The first single FBG optical fiber is configured with at least one fiber corresponding to the pressure beam region for measuring axial pressure; the second single FBG optical fiber is configured with multiple fibers corresponding to the shear beam region for measuring shear force.

[0010] As a further improvement of the present invention, the first notch and the second notch are symmetrical structures with axial widths that gradually decrease and then gradually increase from one end to the other in the circumferential direction.

[0011] As a further improvement of the present invention, the center line connecting the two first gaps is perpendicular to the center line connecting the two second gaps; the center line connecting the two first connecting beams is perpendicular to the center line connecting the two second connecting beams.

[0012] As a further improvement of the present invention, three shear beams are provided, which are evenly distributed along the circumference, and each shear beam is provided with a second single FBG optical fiber.

[0013] As a further improvement of the present invention, the second single FBG optical fiber is fixedly bonded to the outer wall of the shear beam by a first adhesive.

[0014] As a further improvement of the present invention, the first single FBG is configured as one fiber, and the first single FBG fiber and one of the second single FBG fibers are symmetrically arranged with respect to the axis of the sensor body.

[0015] As a further improvement of the present invention, the first single FBG optical fiber is fixedly bonded to the outer wall of the annular short beam by a second adhesive.

[0016] As a further improvement of the present invention, a plurality of axially extending optical fiber channels are arranged circumferentially at intervals on the outer wall of the force sensor body, and the first single FBG optical fiber and the second single FBG optical fiber are fixedly arranged in the optical fiber channels.

[0017] As a further improvement of the present invention, the sensor body is made of a superelastic nickel-titanium alloy.

[0018] As a further improvement of the present invention, an upper slot and a lower slot are respectively provided at both ends of the sensor body. The end of the first connecting beam opposite to the first annular short beam is connected to the upper slot, and the end of the shear beam opposite to the second annular short beam is connected to the lower slot. The upper slot can be connected to the end endoscope lens or other actuator, and the lower slot can be connected to the front flexible actuator.

[0019] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0020] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include:

[0021] (1) The FBG miniature force sensor of the present invention provides a pressure beam area and a shear beam area on the sensor body respectively, and fixes multiple independent single FBG optical fibers on the outer wall of the sensor body respectively corresponding to the pressure beam area and the shear beam area. This enables the sensor to simultaneously measure axial pressure and transverse shear force, while effectively shortening the length of the rigid section of the sensor, thereby shortening the overall length of the sensor. This allows the flexible endoscope end integrating the sensor to maintain a bending capacity of more than 90°.

[0022] (2) The FBG miniature force sensor of the present invention sets the axial width of the notch to decrease first and then increase, which plays a role in structural buffering. This ensures the axial sensitivity of the sensor while constraining the deformation of the connecting beam, effectively limiting the deformation of the connecting beam under unexpected lateral forces or overloads, preventing plastic deformation or fiber damage to the sensor, and improving the sensor's impact resistance and reliability. At the same time, by setting the two sets of notches and the two sets of connecting beams to be staggered at 90°, the deformation of the connecting beam is constrained in all directions and from multiple angles.

[0023] (3) The FBG miniature force sensor of the present invention has fiber optic channels set on the outer wall of the sensor corresponding to each single FBG fiber, so as to avoid occupying any working channel or instrument channel inside the endoscope.

[0024] (4) The FBG miniature force sensor of the present invention has a reasonable structure and simultaneously solves the problems of channel occupation, excessively long rigid section, weak overload resistance and biocompatibility requirements. It is a miniaturized, highly flexible and highly reliable FBG force sensor solution, realizing seamless, safe and high-performance integration of flexible sensor at the end of flexible endoscope in narrow space. It has good application prospects and promotion value. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a front view of the FBG miniature force sensor in an embodiment of the present invention;

[0027] Figure 2 This is a cross-sectional schematic diagram of the FBG miniature force sensor in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the sensor body in an embodiment of the present invention;

[0029] Figure 4 This is a side view of the FBG miniature force sensor in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the pressure beam region in an embodiment of the present invention;

[0031] Figure 6 This is a simulation comparison diagram of the bending moment effect of the double V-shaped notch and the rectangular notch of the FBG micro force sensor in the embodiment of the present invention.

[0032] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Sensor body; 101. Pressure beam area; 1011. First notch; 1012. First connecting beam; 1013. Second notch; 1014. Second connecting beam; 1015. First annular short beam; 1016. Second annular short beam; 102. Shear beam area; 1021. Shear beam; 103. Fiber optic channel; 104. Upper slot; 105. Lower slot; 2. First single FBG fiber; 3. Second single FBG fiber; 4. First adhesive; 5. Second adhesive. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0034] In the description of this invention, it should be understood that, unless otherwise expressly specified and limited, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0035] Furthermore, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] Example:

[0039] Please see Figures 1-6 In a preferred embodiment of the present invention, the FBG miniature force sensor includes a sensor body 1, a first single FBG optical fiber 2, and a second single FBG optical fiber 3. The sensor body 1 is provided with a pressure beam region 101 and a shear beam region 102, so that when the sensor body 1 is subjected to force, the corresponding beam region deforms. The deformation is converted into a change in optical signal through the first single FBG optical fiber 2 and the second single FBG optical fiber 3, thereby calculating the magnitude of the force on the sensor body 1.

[0040] Specifically, in the preferred embodiment, the sensor body 1 is a hyperelastic tubular structure, and more preferably a hyperelastic nickel-titanium alloy tube, which can completely restore its original shape after large strain unloading, thereby greatly improving the reliability and service life of the sensor. This makes the sensor body 1 have good biocompatibility, meet the relevant standards for medical device implants, and be suitable for the in vivo environment. It is also suitable for micro-machining processes such as precision laser cutting, which makes it easy to set complex force sensing structures such as beams and notches on the sensor body 1.

[0041] like Figure 1 As shown, in the preferred embodiment, the sensor body 1 includes an upper slot 104, a pressure beam area 101, a shear beam area 102, and a lower slot 105 arranged sequentially along the axial direction. The upper slot 104 and the lower slot 105 are respectively located at both ends of the sensor body 1, so as to connect to the end endoscope lens or other actuator through the upper slot 104 and to connect to the front flexible actuator through the lower slot 105. At the same time, the pressure beam area 101 is located near the upper slot 104 for sensing axial pressure, and the shear beam area 102 is located near the lower slot 105 for sensing lateral shear force.

[0042] More specifically, such as Figure 5As shown, the pressure beam region 101 includes a first connecting beam 1012, a second connecting beam 1014, a first annular short beam 1015, and a second annular short beam 1016; wherein, the first connecting beam 1012 and the second connecting beam 1014 extend axially and are symmetrically arranged as two beams along the axis of the sensor body 1, and a first notch 1011 is provided between the two sides of the two first connecting beams 1012, and a second notch 1013 is provided between the two sides of the two second connecting beams 1014.

[0043] Understandably, in actual use, the first connecting beam 1012 will sequentially transfer the load borne by the upper slot 104 to the first annular short beam 1015, the second connecting beam 1014, the second annular short beam 1016 and the shear beam area 102. During the process of transmitting axial force, the first connecting beam 1012, the first annular short beam 1015, the second connecting beam 1014 and the second annular short beam 1016 will all undergo compressive deformation, thereby sensing the axial force.

[0044] Meanwhile, one axial end of the first annular short beam 1015 is connected to the first connecting beam 1012, and the other end is connected to the second connecting beam 1014. The end of the first connecting beam 1012 away from the first annular short beam 1015 is connected to the upper slot 104. The end of the second connecting beam 1014 away from the first annular short beam 1015 is connected to the second annular short beam 1016. The second annular short beam 1016 is connected to the shear beam zone 102.

[0045] Accordingly, the shear beam zone 102 includes multiple shear beams 1021 spaced apart along the circumference. One end of each shear beam 1021 is connected to one end of the second annular short beam 1016 away from the second connecting beam 1014, and the other end is connected to the lower slot 105, so as to sense the lateral shear force through the shear beams 1021.

[0046] In one specific embodiment of the present invention, the shear beam region 102 is provided with three shear beams 1021, and the three shear beams 1021 are evenly spaced along the circumference. Of course, more shear beams 1021 evenly spaced along the circumference can also be provided, depending on the specific needs. However, it should be noted that, under the premise that the circumferential width of the shear beams 1021 remains unchanged, the more shear beams 1021 are provided, the greater the stiffness of the shear beam region 102, and the lower the sensitivity of the sensor to axial forces.

[0047] In practical use, the first connecting beam 1012 and the second connecting beam 1014 are more sensitive to lateral forces than the shear beam 1021. Therefore, the sensor is at risk of plastic deformation under lateral forces. Thus, it is preferable to set both the first notch 1011 and the second notch 1013 as symmetrical structures with axial widths gradually decreasing and then gradually increasing from one end to the other in the circumferential direction, forming a structure as follows: Figure 5The double V-shaped notch structure shown in the figure effectively limits the deformation of the connecting beam under unexpected lateral forces or overloads by utilizing the structural buffering and deformation restraint effects of the double V-shaped region. This prevents plastic deformation of the sensor or damage to the optical fiber, thereby improving the sensor's impact resistance and reliability.

[0048] More preferably, the center line connecting the two first gaps 1011 is perpendicular to the center line connecting the two second gaps 1013, and the center line connecting the two first connecting beams 1012 is also perpendicular to the center line connecting the two second connecting beams 1014, so as to ensure that the two sets of gaps provide all-round constraint on the deformation of the two sets of connecting beams.

[0049] like Figure 6 As shown in the figure, the upper left and upper right figures are deformation cloud maps of the double V-shaped notch (vertex angle θ is 20°), and the maximum deformation of the sensor is 0.385 mm. The lower left and lower right figures are deformation cloud maps of the rectangular notch with constant axial width, and the maximum deformation of the sensor is 0.476 mm. This shows that the buffering effect of the double V-shaped notch structure significantly reduces the overload deformation of the sensor.

[0050] In actual setup, the apex angle θ of the double V-shaped notch can be adjusted according to the range and stiffness requirements of the target sensor to achieve optimal overload deformation constraint while ensuring the axial force sensitivity of the pressure beam zone 101. It is known that a smaller apex angle provides stronger deformation constraint and higher overload resistance, suitable for smaller ranges and higher sensitivity requirements; a larger apex angle provides relatively higher sensitivity, suitable for larger range requirements.

[0051] In actual manufacturing, the outer peripheral wall of the tubular sensor body 1 can be cut by laser cutting or micro-milling to form connecting beams, notches, annular short beams 1015 and shear beams 1021 of specific size and shape.

[0052] Furthermore, in the preferred embodiment, the first single FBG fiber 2 and the second single FBG fiber 3 are fixedly disposed on the outer wall of the sensor body 1; wherein, the first single FBG fiber 2 is disposed in the pressure beam region 101 for measuring axial pressure, and the second single FBG fiber 3 is disposed in the shear beam region 102 for measuring shear force.

[0053] Preferably, an axially extending fiber optic channel 103 is provided on the outer wall of the sensor body 1 for each of the first single FBG fiber 2 and the second single FBG fiber 3, so as to fix the first single FBG fiber 2 and the second single FBG fiber 3 in the fiber optic channel 103, avoiding the single FBG fiber from occupying any working channel or instrument channel inside the endoscope, ensuring the integrity of the endoscope's imaging fiber, flushing / suction channel and other functional components, and realizing the true integration of the sensing module and the mechanical end function.

[0054] Preferably, there are multiple second single FBG optical fibers 3, and the multiple second single FBG optical fibers 3 are evenly spaced along the circumferential direction.

[0055] Preferably, the number of second single FBG optical fibers 3 is the same as the number of shear beams 1021, and preferably the optical fiber channels 103 corresponding to the second single FBG optical fibers 3 are all set on the outer wall of each shear beam 1021, so as to ensure that the second single FBG optical fibers 3 can bend better with the bending of the shear beam 1021 when the sensor bends, thereby improving the measurement accuracy.

[0056] When considering the bending stiffness of the shear beam region 102, and the number of shear beams 1021 is not equal to the number of second single FBG optical fibers 3, it is preferable to set at least one optical fiber channel 103 corresponding to the second single FBG optical fiber 3 on the outer wall of the shear beam 1021, so as to set at least one second single FBG optical fiber 3 on the outer wall of the shear beam 1021, so as to facilitate subsequent shear force calculation.

[0057] In another specific embodiment of the present invention, such as Figure 1 As shown, four shear beams 1021 are evenly arranged circumferentially within the shear beam region 102, and three second single FBG optical fibers 3 are correspondingly arranged within the shear beam region 102, as shown. Figure 4 As shown, three second single FBG optical fibers 3 are evenly distributed at 120° intervals along the circumferential direction. One of the second single FBG optical fibers 3 is set in the optical fiber channel 103 on the outer wall of the shear beam 1021, and the FBG grid length of each second single FBG optical fiber 3 is greater than the axial length of the shear beam 1021.

[0058] More preferably, the first single FBG optical fiber 2 is fixedly bonded to the optical fiber channel 103 by the second adhesive 5, and the second single FBG optical fiber 3 is fixedly bonded to the optical fiber channel 103 by the first adhesive 4, ensuring that the second single FBG optical fiber 3 will not slip during the bending deformation of the shear beam 1021, and will bend together with the sensor body 1, thereby sensing the deformation of the shear beam 1021 and measuring the transverse shear force of the sensor.

[0059] Preferably, a first single FBG optical fiber 2 is provided corresponding to the pressure beam region 101, and the FBG grid region of the first single FBG optical fiber 2 covers all the notched areas. More preferably, the first single FBG optical fiber 2 is fixed to the optical fiber channel 103 corresponding to the outer wall of the pressure beam region 101 by a second adhesive 5, and is further preferably fixed to the outer surface of the first annular short beam 1015 and the second annular short beam 1016, so as to measure the axial pressure of the sensor by sensing the deformation of the annular short beam 1015; and further preferably, the first single FBG optical fiber 2 and one of the second single FBG optical fibers 3 are symmetrically arranged with respect to the axis of the sensor body 1, so as to simplify the subsequent temperature decoupling and force solution steps.

[0060] The principle of the aforementioned sensor force measurement is as follows: When shear force acts on the endoscope, it is transmitted to the shear beam region 102 through the upper slot 104. The shear beam 1021 in the shear beam region 102 deforms, and the second single FBG fiber 3 fixed in the shear beam region 102 deforms synchronously. According to the characteristics of FBG fiber, the center wavelength of the emitted light will change under the action of strain and temperature. The shear force can be measured by using a demodulator and a temperature decoupling algorithm. Similarly, when axial force acts on the endoscope, it is transmitted to the pressure beam region 101 and the shear beam region 102 through the upper slot 104, causing deformation. By using the combination of the wavelength offsets of the three second single FBG fibers 3, the influence of temperature change on the first single FBG fiber 2 can be decoupled, so as to perform temperature compensation on the axial force measured by the first single FBG fiber 2. The axial force can then be measured by using a demodulator and the corresponding temperature decoupling algorithm. The specific algorithm involved in this measurement process is existing technology and will not be elaborated here.

[0061] This invention employs an independent single-FBG fiber layout, completely eliminating the grating isolation length required by traditional dual-FBG fiber schemes. This significantly reduces the effective rigid length of the sensor to ≤3mm, and the shortening of the rigid section further reduces the overall sensor length to ≤5mm. When integrated into the end of a flexible endoscope, this sensor has minimal impact on the overall bending stiffness of the instrument. This ensures that the rigid portion of the endoscope will not accidentally contact human tissue during large-angle bending, meeting the operational requirements of narrow and tortuous cavities such as the maxillary sinus. The flexible endoscope integrating this sensor maintains a high degree of bending freedom of ≥90° in the vicinity of the end area, with a significantly reduced bending radius, thereby greatly improving the instrument's passability and operational flexibility in narrow and tortuous anatomical environments (such as the maxillary sinus).

[0062] This invention utilizes a combination of superelastic nickel-titanium alloy material and laser cutting technology to construct a shear beam region and a V-notch pressure beam region structure with independent single FBG optical fibers on the outer wall. While solving the problems of traditional sensors occupying channels and restricting bending degrees of freedom, this invention achieves three-dimensional force decoupling measurement through a novel fiber layout. The V-notch structure on the connecting beam 4 reduces overload deformation by more than 10%, keeping the sensor's outer diameter within 3.0 mm without hindering the large-angle bending capability of the flexible actuator at the sensor's front end. This solution not only achieves a reliable connection between the endoscope tip and the actuator through interference fit but also verifies its impact resistance and measurement stability through simulation. It provides a force sensing solution for minimally invasive surgeries such as those involving stenosis of the maxillary sinus, offering miniaturization, high flexibility, and overload resistance, effectively promoting the integrated application of force sensing at the endoscope tip and surgical manipulation.

[0063] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An FBG miniature force sensor, characterized in that, Includes the sensor body, the first single FBG optical fiber, and the second single FBG optical fiber; The sensor body is a hyperelastic tubular structure, including a pressure beam area and a shear beam area arranged sequentially along the axial direction; The pressure beam region is used to sense axial pressure and includes a first connecting beam, a first annular short beam, a second connecting beam, and a second annular short beam. Two first connecting beams and two second connecting beams are symmetrically arranged along the axis of the sensor body, with a first notch between each side of the two first connecting beams and a second notch between each side of the two second connecting beams. The first and second notches are symmetrical structures with axial widths that gradually decrease and then gradually increase from one end to the other circumferentially. The center line connecting the two first notches is perpendicular to the center line connecting the two second notches, and the center line connecting the two first connecting beams is perpendicular to the center line connecting the two second connecting beams. One axial end of the first annular short beam is connected to the first connecting beam, and the other end is connected to the second connecting beam. The other end of the second connecting beam is connected to the second annular short beam, which is connected to the shear beam region. The shear beam zone is used to sense lateral shear force and includes multiple shear beams spaced apart circumferentially, which are connected to the second annular short beam; The first single FBG optical fiber is configured as at least one in the pressure beam area and is fixed to the outer wall of the sensor body for measuring axial pressure; the second single FBG optical fiber is configured as multiple in the shear beam area and is fixed to the outer wall of the sensor body at circumferential intervals for measuring shear force.

2. The FBG miniature force sensor according to claim 1, characterized in that, The shear beam is provided with three beams, which are evenly distributed circumferentially, and each shear beam is provided with a second single FBG optical fiber.

3. The FBG miniature force sensor according to claim 2, characterized in that, The second single FBG optical fiber is fixedly bonded to the outer wall of the shear beam by the first adhesive.

4. The FBG miniature force sensor according to claim 2, characterized in that, The first single FBG fiber is configured as one, and the first single FBG fiber and one of the second single FBG fibers are symmetrically arranged with respect to the axis of the sensor body.

5. The FBG miniature force sensor according to claim 4, characterized in that, The first single FBG optical fiber is fixedly bonded to the outer wall of the annular short beam by a second adhesive.

6. The FBG miniature force sensor according to claim 1, characterized in that, Multiple axially extending optical fiber channels are arranged circumferentially at intervals on the outer wall of the force sensor body, and the first single FBG optical fiber and the second single FBG optical fiber are fixedly arranged in the optical fiber channels.

7. The FBG miniature force sensor according to claim 1, characterized in that, The sensor body is made of a superelastic nickel-titanium alloy.

8. The FBG miniature force sensor according to claim 1, characterized in that, The sensor body has an upper slot and a lower slot at both ends. The end of the first connecting beam opposite to the first annular short beam is connected to the upper slot, and the end of the shear beam opposite to the second annular short beam is connected to the lower slot. The upper slot can be connected to the end endoscope lens or other actuators, and the lower slot can be connected to the front flexible actuator.

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