Temperature self-compensating array pressure sensor based on fiber Bragg grating

Abstract

This invention discloses a temperature-compensated array-type pressure sensor based on a fiber Bragg grating. The sensor includes a front cover, a force sensing array, a rear cover, a tail rod, a diaphragm, and fasteners. The force sensing array is divided into an upper sensing array and a lower sensing array. Each sensing array includes an elastic sensor and a string of gratings, suspended in pairs on both sides of the elastic sensor to form a force sensing array with 24 sensing units. The front and rear covers support two opposing force sensing arrays and are fixed by fasteners. A flexible diaphragm encloses the entire structure. When the sensor comes into contact with local human tissue, the pressure causes the cantilever beam to bend, resulting in equal and opposite strains in the suspended optical fibers. This causes equal and opposite drifts in the center wavelength of the fiber Bragg grating's reflection spectrum. By monitoring the difference between these two drifts, multi-point measurement of local human tissue pressure is achieved, eliminating the influence of temperature.

Description

Technical Field

[0001] This invention relates to the field of distributed pressure measurement technology, and specifically to a temperature self-compensating array pressure sensor based on fiber Bragg gratings. Background Technology

[0002] Due to factors such as vaginal delivery, multiple births, and a history of pelvic surgery, women's pelvic floor tissues can suffer various types of damage or trauma, inducing pelvic floor dysfunction disorders, mainly including pelvic organ prolapse and urinary incontinence, with urinary incontinence being the most common. Studies have shown that the prevalence of pelvic floor dysfunction disorders worldwide ranges from 20% to 77%, seriously impacting patients' physical and mental health and daily lives. Accurately assessing the functional status of the pelvic floor muscles is crucial for the diagnosis, treatment, and prognosis of pelvic floor diseases. While currently used clinical methods such as quantitative grading of pelvic organ prolapse, three-dimensional ultrasound, and MRI can guide diagnosis and treatment, they cannot effectively evaluate the biomechanical function of the pelvic floor muscles.

[0003] Vaginal tactile imaging is a novel method for evaluating pelvic floor tissues that has emerged in recent years. It can accurately measure and quantitatively evaluate the functional status of pelvic floor tissues and visualize the results. The core of vaginal tactile imaging lies in using a transvaginal probe to simulate the palpation behavior of a finger under specific actions, thereby determining the mechanical properties of various local tissues of the vaginal wall. Existing vaginal probes fall into two categories: one type uses a force sensor at the tip of a speculum or retractable rod, or measures the force at different locations in the vagina using a pressure balloon; however, this is difficult to operate and limits the number of measurement points. The other type uses a pressure sensor array, measuring the pressure on the vaginal wall through an array of atmospheric pressure sensors or contact force sensors. While this increases the number of measurement points, it is still insufficient for tactile imaging. Furthermore, the impact of changes in internal and external environmental temperature on measurement results (the core body temperature is approximately 37°C, while the ambient temperature in a typical examination room is approximately 25°C, a difference of up to 12°C. When the probe is inserted into the body cavity from room temperature, its sensor unit undergoes a rapid temperature rise. For resistive strain gauges or capacitive pressure sensors, the resistivity, dielectric constant, and other parameters of their sensitive materials exhibit significant temperature dependence, with typical temperature drift coefficients reaching 0.1%~0.5% / °C. This means that a 12°C temperature difference could introduce 1.2%~6% zero-point drift and sensitivity error, far exceeding the acceptable range for pelvic floor pressure measurement (typically requiring an error of <1%)), which has not been considered in previous designs and studies.

[0004] In summary, existing pressure probes for pelvic floor function assessment suffer from insufficient measurement points and fail to consider the effects of temperature. Therefore, this invention provides a temperature-compensated array pressure sensor based on a fiber Bragg grating, aiming to achieve high spatial resolution multi-point distributed pressure measurement and automatically compensate for measurement errors caused by temperature changes. Summary of the Invention

[0005] The purpose of this invention is to provide a pressure sensing probe to achieve multi-point distributed measurement of local tissue pressure in the human body with temperature self-compensation.

[0006] The second objective of this invention is to provide a monitoring method for a temperature self-compensating array pressure sensor based on a fiber Bragg grating.

[0007] To address the aforementioned technical problems, this invention provides a technical solution: a temperature self-compensating array-type pressure sensor based on a fiber Bragg grating, comprising a front cover, a force sensing array, a rear cover, a tail rod, fasteners, and a coating, wherein...

[0008] When the sensor is placed horizontally, the front cover and the rear cover are located on the front and rear sides of the sensor, respectively. When they fit together, they form a cavity to support and fix the sensor array.

[0009] The force sensing array consists of an upper sensing array and a lower sensing array. The upper sensing array comprises an elastic sensor and four grating strings, namely the first to the fourth grating strings. The upper sensing array has two rows of twenty-four sensing units arranged in a staggered manner, namely the first to the twenty-fourth sensing units. The lower sensing array has the same structure as the upper sensing array, with the twenty-fifth to forty-eighth sensing units on top of it. The sensing units of the upper sensor array point upwards from the sensor, while the sensing units of the lower sensor array point downwards from the sensor.

[0010] The tail rod is located behind the sensor and is connected to the front cover and the rear cover. It is used to support the overall structure of the sensor and to arrange the pigtails of the grating string.

[0011] Fasteners connect and secure the front and rear covers;

[0012] The coating is a flexible structure that wraps around the front cover, sensor array, rear cover and tail rod, protecting them from bodily fluid corrosion.

[0013] The elastic sensor has multiple cantilever beam structures. The first and second grating strings of the four grating strings of the elastic sensor are fixed to the first and second sides of each cantilever beam structure, respectively. The first and second grating strings generate axial strains of opposite signs as the cantilever beams deform. The sensor achieves temperature self-compensation for pressure measurement by detecting the difference in wavelength shift between the corresponding gratings in the first and second grating strings.

[0014] As a preferred technical solution, the upper sensor array consists of an elastic sensor and four grating strings, wherein,

[0015] The elastic sensor has a double-sided structure connected by a thin plate in the middle. Thirteen semi-racetrack-shaped protrusions are arranged equidistantly on the upper and lower parts of the front side, namely the first to thirteenth upper protrusions and the first to thirteenth lower protrusions, respectively. Twelve T-shaped cantilever beams are arranged equidistantly in the middle, namely the first to twelfth cantilever beams. Each T-shaped cantilever beam consists of a vertical and a horizontal structure, which are perpendicular to each other. The rear section of the horizontal structure of the T-shaped cantilever beam connects to the thin plate, and the suspended section is spaced apart from the thin plate. The lower end of the vertical structure of the T-shaped cantilever beam has an arc-shaped transition structure with a circular groove for fixing the grating string; this is called the lower transition structure. Its upper end is a cuboid structure, with the top end contacting the coating to transmit force. The middle part is open and has an arc-shaped transition structure with a circular groove for fixing the grating string; this is called the upper transition structure. The vertical structure of the T-shaped cantilever beam is located between two adjacent semi-racetrack-shaped protrusions on the left and right, while its horizontal structure is located between two rows of protrusions on the top and bottom. The tops of the equidistantly arranged vertical structures of the T-shaped cantilever beam are used to contact the object being measured, and are called contact points. The rear structure of the elastic sensor is the same as the front structure, but the positions of its protrusions and cantilever beams are shifted compared to the front, so that the first cantilever beam on the rear side is located between the first and second cantilever beams on the front side, and the protrusion positions also correspond accordingly.

[0016] There are four grating strings, with single-mode optical fiber as the substrate. These are the first to fourth grating strings. Each grating string has twelve gratings etched at equal intervals, namely the first to the twelfth gratings. The center wavelengths of the reflection spectra of the twelve gratings are in an arithmetic sequence. The grating spacing is the sum of the distances between the semi-runway-shaped protrusion of the elastic sensor, the T-shaped cantilever beam transition structure, and the semi-runway-shaped protrusion.

[0017] The first grating string is suspended between the upper boss of the elastic sensor and the upper arc-shaped transition structure of the T-shaped cantilever beam vertical structure, and the second grating string is suspended between the lower boss of the elastic sensor and the lower arc-shaped transition structure of the T-shaped cantilever beam vertical structure, with the gratings located in the fiber suspension section. The upper first boss, upper second boss, lower first boss, lower second boss, front first cantilever beam, first grating string, and second grating string constitute the first sensing unit, and the center wavelengths of the first grating string and the second grating string are equal; and so on, the front boss and cantilever beam, the first grating string, and the second grating string constitute the first to twelfth sensing units;

[0018] The rear structure and grating string arrangement of the elastic sensor are the same as those of the front. The position of its semi-racetrack-shaped boss and T-shaped cantilever beam is shifted backward compared to the front. The rear boss and cantilever beam, the third grating string and the fourth grating string constitute the thirteenth to twenty-fourth sensing units, so that the rear sensing unit array and the front sensing unit array are arranged side by side with staggered positioning.

[0019] As a preferred technical solution, the lower sensing array is configured in the same way as the upper sensing array. The two structures are mirror-symmetrical about the horizontal plane and are arranged back to back. The upper part contains the twenty-fifth to forty-eighth sensing units. When the two are combined, a semi-runway-shaped protrusion is formed in the upper and lower parts of the overall structure, and a runway-shaped protrusion is formed in the middle of the structure.

[0020] As a preferred technical solution, the rear cover has a thin shell structure, the front section is a semi-circular thin-walled structure with a stepped hole in the middle; the middle section is a rectangular thin-walled structure with semi-racetrack-shaped grooves arranged on its upper and lower sides and a racetrack-shaped groove arranged in its middle, the groove positions corresponding to the positions of the rear protrusions after the upper elastic sensor and the lower sensor are engaged; the rear section is a trapezoidal thin shell structure.

[0021] As a preferred technical solution, the front cover and the rear cover have the same structure, but the semi-racetrack and racetrack-shaped grooves are slightly displaced compared to the rear cover. Their positions correspond to the positions of the front protrusions after the upper elastic sensor and the lower sensor are engaged. After the front cover and the rear cover are engaged, a hollow structure is formed to house the sensor array and provide support and fixation.

[0022] As a preferred technical solution, the tail rod is a stepped cylindrical structure. The shape and size of the front end match the shape and size of the front cover and the rear cover after they are fitted together. After they are fitted together, they form a relatively closed structure to support the overall structure of the sensor. The tail rod is arranged with the grating string of the pigtail.

[0023] As a preferred technical solution, the fasteners are standard screws and nuts, which fix the front cover and the rear cover together at the stepped hole position at the front end.

[0024] As a preferred technical solution, the coating is a flexible thin film structure, fabricated using a molding method with flexible hydrogel material. The shape and dimensions of its inner wall match the shape and dimensions of the outer wall formed by the front and rear covers. Square protrusions are arranged on the upper and lower parts of the inner wall, their number and position corresponding to the number and position of the sensing units in the sensor array. These protrusions are, respectively, the first square protrusion on the upper front side to the dodecagonal protrusions on the upper front side, the first square protrusion on the upper rear side to the dodecagonal protrusions on the upper rear side, the first square protrusion on the lower front side to the dodecagonal protrusions on the lower front side, and the first square protrusion on the lower rear side to the dodecagonal protrusions on the lower rear side. The coating utilizes its flexibility to encapsulate the remaining structure of the sensor, protecting it from bodily fluid intrusion.

[0025] As a preferred technical solution, the front cover, rear cover, elastic sensor, and tail rod are all processed and formed by photopolymerization 3D printing.

[0026] To achieve the second objective mentioned above, the technical solution adopted by the present invention is as follows:

[0027] A monitoring method for a temperature self-compensating array pressure sensor based on a fiber Bragg grating, utilizing any of the above embodiments, the method comprising the following steps:

[0028] S1. The flexible membrane of the sensor is brought into contact with local tissue of the human body. The pressure is transmitted through the membrane to the T-shaped cantilever beam contact inside the sensor, and the pressure signal is collected by the sensing array sensing unit arranged above and below.

[0029] S2. Under pressure, the T-shaped cantilever beam undergoes bending deformation, causing the fiber optic gratings suspended above and below within the same sensing unit to generate positive and negative strains respectively, resulting in equal and opposite shifts in the center wavelength of the corresponding grating reflection spectrum. By monitoring the difference in the center wavelength shift of the corresponding gratings above and below within the same sensing unit, and combining the cantilever beam mechanical model, geometric relationships, and fiber optic grating strain-wavelength shift relationship, the multi-point pressure values ​​of local tissues in the human body can be calculated.

[0030] S3. Temperature changes cause equal and same wavelength drift in the upper and lower gratings within the same sensing unit. By calculating the wavelength drift difference in step S2, the interference of temperature-induced wavelength drift on the pressure calculation results is eliminated, thus realizing temperature self-compensation and multi-point distributed pressure measurement.

[0031] As a preferred technical solution, temperature self-compensation is achieved and pressure measurement sensitivity is improved through wavelength drift difference calculation; the initial center wavelengths of corresponding gratings in the same sensing unit are equal, ensuring that the temperature drift is consistent and the pressure strain drift is opposite.

[0032] The beneficial effects of this invention are:

[0033] 1. Achieving High Spatial Resolution Multi-Point Distributed Pressure Measurement: This invention utilizes an array of multiple T-shaped cantilever beams (1-T01 to 1-T12) arranged on an elastic sensor (1-E). Each cantilever beam independently constitutes a sensing unit. Furthermore, by staggering the cantilever beams on the front and rear sides (the rear cantilever beam is located between two adjacent front cantilever beams), dense filling of sensing units is achieved within a limited space. This structure enables the sensor to simultaneously acquire pressure information from 48 independent measurement points (24 on the upper and 24 on the lower sensing array). The spatial resolution is significantly higher than that of existing single-point or sparse array probes, providing ample data support for precise imaging of the mechanical functions of local tissues such as the pelvic floor muscles.

[0034] 2. Achieving Sensorless Temperature Self-Compensation: This invention suspends and fixes two independent grating strings (first grating string 1-F1 and second grating string 1-F2) mirror-symmetrically on the upper and lower sides of each T-shaped cantilever beam. This structure ensures that: when the temperature changes, the upper and lower gratings produce identical wavelength shifts; when pressure is applied, the upper and lower gratings produce strains of equal magnitude but opposite direction due to the bending deformation of the cantilever beam, resulting in wavelength shifts of opposite signs. By subtracting the wavelength shifts of the two gratings, the temperature contributions cancel each other out, and the pressure contributions are added together for output (signal doubling). This mechanism requires no additional temperature sensors, thermistors, or compensation circuits; it automatically eliminates the influence of ambient temperature changes (including the temperature difference between room temperature and body temperature when the probe is placed in the body and local tissue temperature fluctuations) on the pressure measurement results solely through structural design, significantly improving measurement accuracy and environmental adaptability.

[0035] 3. The dual-grating differential structure simultaneously improves pressure measurement sensitivity: In the aforementioned differential output mode, the wavelength shift caused by pressure is doubled compared to a single grating, resulting in a doubling of sensitivity. Compared to traditional pressure sensors with a single grating or a single sensing element, this invention achieves a natural improvement in measurement sensitivity through structural arrangement without increasing the difficulty of grating writing or the complexity of the demodulation system, which is beneficial for detecting minute changes in tissue pressure.

[0036] 4. Achieving Consistent Measurement Amid Temperature Gradient Fields: Since the spacing between the upper and lower gratings of each sensing unit is only a few millimeters, and they use the same materials and initial wavelength, each unit independently performs temperature self-compensation. Even if temperature gradients exist at different locations within the sensor array (e.g., the probe tip contacts the tissue at a higher temperature while the rear end remains at a lower temperature), the differential output of each unit can effectively offset the changes in the local temperature field of that unit, thus ensuring that the pressure output values ​​at all measurement points across the entire array have a consistent temperature reference. This is particularly important for multi-point pressure imaging in vivo, avoiding spurious pressure differences caused by uneven temperature distribution.

[0037] 5. Excellent biocompatibility and electromagnetic compatibility: This invention uses a fiber optic grating as the sensing element, photocurable resin as the elastic sensor and housing material, and hydrogel as the coating material. The entire sensor contains no metal electrodes or electronic components. Therefore, the sensor can be safely used in combined examinations under MRI without producing electromagnetic interference or image artifacts. Furthermore, the fiber optic grating itself possesses electrical insulation, corrosion resistance, and resistance to body fluid erosion. Combined with the coating, it is suitable for long-term use in humid and complex environments such as human cavities.

[0038] 6. Compact structure, easy to miniaturize and mass-produce: In this invention, the front cover, rear cover, elastic sensor, and tail rod are all integrally formed using photopolymerization 3D printing, eliminating the need for complex assembly processes, resulting in high manufacturing precision and controllable costs. The T-shaped cantilever beam and boss combined with the grating suspension and fixation structure design make the tension and positioning of the grating string more reliable, suitable for mass production. At the same time, the overall structure is compact (only a few centimeters wide), adapting to the integration needs of small-sized medical devices such as transvaginal probes.

[0039] 7. Real-time measurement process and fast dynamic response: The wavelength demodulation speed of fiber optic gratings can reach the kHz level, and the transmission path between the bending deformation of each cantilever beam and the strain of the grating is short and without mechanical hysteresis. Therefore, this invention can track dynamic pressure changes in real time and is suitable for evaluating rapid mechanical processes such as pelvic floor muscle contraction and Valsalva maneuvers, providing dynamic pressure curves for functional diagnosis.

[0040] 8. Achieving high spatial resolution multi-point distributed measurement of local tissue pressure in the human body through the spatial arrangement of T-shaped cantilever beams and the suspension of fiber optic gratings;

[0041] 9. By setting up dual-row fiber optic gratings and arranging them in opposite directions, the center wavelength shifts of the corresponding gratings are the same and opposite under the influence of force and temperature, respectively; the difference between the two is used as the output of the sensor to eliminate the influence of temperature changes on the measurement results and achieve temperature self-compensation. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the overall structure of a temperature self-compensating array pressure sensor based on a fiber Bragg grating according to an embodiment of the present invention.

[0043] Figure 2 This is a schematic diagram of the upper sensing array structure of a temperature self-compensating array pressure sensor based on a fiber Bragg grating according to an embodiment of the present invention.

[0044] Figure 3 This is a schematic diagram of the upper sensing array sensing unit structure of a temperature self-compensating array pressure sensor based on a fiber Bragg grating according to an embodiment of the present invention.

[0045] Figure 4 This is a schematic diagram of the sensing unit arrangement of a temperature self-compensating array pressure sensor based on a fiber Bragg grating according to an embodiment of the present invention.

[0046] Figure 5 This is a schematic diagram of the back cover structure of a temperature self-compensating array pressure sensor based on a fiber Bragg grating according to an embodiment of the present invention.

[0047] Figure 6 This is a schematic diagram of the coating structure of a temperature self-compensating array pressure sensor based on a fiber Bragg grating according to an embodiment of the present invention.

[0048] Figure 7 This is a schematic diagram of the force applied to the sensing unit of a temperature self-compensating array pressure sensor based on a fiber Bragg grating according to an embodiment of the present invention.

[0049] Figure 8 This is a schematic diagram of the deformation of the sensing unit of a temperature self-compensating array pressure sensor based on a fiber optic grating according to an embodiment of the present invention after being subjected to force.

[0050] In the picture:

[0051] 1: Upper sensor array, 2: Lower sensor array, 3: Rear cover, 4: Fastening nut, 5: Front cover, 6: Fastening screw, 7: Cover film, 8: Tail rod;

[0052] 1-E: Elastic sensor, 1-P: Thin plate, 1-T01: First T-shaped cantilever beam, 1-T02: Second T-shaped cantilever beam, 1-T12: Twelfth T-shaped cantilever beam, 1-F1: First grating string, 1-F2: Second grating string, 1-F3: Third grating string, 1-F4: Fourth grating string, 1-BA01: Upper first boss, 1-BA13: Upper thirteenth boss, 1-BB01: Lower first boss, 1-BB13: Lower thirteenth boss;

[0053] S01: First sensing unit, S02: Second sensing unit, S03: Third sensing unit, S12: Twelfth sensing unit, 1-F101: First grating string with first grating, 1-F201: Second grating string with first grating, 1-T0101: First cantilever beam transverse structure, 1-T0102: First cantilever beam vertical structure; 1-BA02: Upper second boss, 1-BB02: Lower second boss, 1-F112: First grating string with twelfth grating, 1-F212: Second grating string with twelfth grating, 1-T1201: Twelfth cantilever beam transverse structure, 1-T1202: Twelfth cantilever beam vertical structure; 1-BA12: Upper twelfth boss, 1-BB12: Lower twelfth boss;

[0054] S06: Sixth sensory unit, S13: Thirteenth sensory unit, S18: Eighteenth sensory unit, S24: Twenty-fourth sensory unit, S25: Twenty-fifth sensory unit, S30: Thirtieth sensory unit, S36: Thirty-sixth sensory unit, S37: Thirty-seventh sensory unit, S42: Forty-second sensory unit, S48: Forty-eighth sensory unit.

[0055] 301: Stepped holes on the rear cover; 302: Racetrack-shaped groove on the rear cover; 303: Semi-racetrack-shaped groove on the rear cover.

[0056] 7-A01: First square protrusion on the front side of the upper part; 7-A12: Twelfth square protrusion on the front side of the upper part; 7-B01: First square protrusion on the rear side of the upper part; 7-B12: Twelfth square protrusion on the rear side of the upper part. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0058] A temperature self-compensating array-type pressure sensor based on a fiber Bragg grating includes an upper sensing array 1, a lower sensing array 2, a rear cover 3, a fastening nut 4, a front cover 5, fastening screws 6, a diaphragm 7, and a tail rod 8.

[0059] When the sensor is placed horizontally, the front cover 5 and the rear cover 3 are located on the front and rear sides of the sensor, respectively. When they are put together, they form a cavity to support and fix the upper sensor array 1 and the lower sensor array 2.

[0060] The force sensing array consists of an upper sensing array 1 and a lower sensing array 2. The upper sensing array 1 is composed of an elastic sensor 1-E and four grating strings, namely the first grating string 1-F1 to the fourth grating string 1-F4. The upper sensing array 1 has two rows of parallel staggered sensing units, totaling twenty-four, namely the first sensing unit S01 to the twenty-fourth sensing unit S24. The lower sensing array 2 has the same structure as the upper sensing array, with the twenty-fifth sensing unit S25 to the forty-eighth sensing unit S48 on top of it.

[0061] The tail rod 8 is located behind the sensor and is connected to the front cover 5 and the rear cover 3. It is used to support the overall structure of the sensor and to arrange the pigtails of the grating string.

[0062] Tighten nuts 4 and screws 6 to connect and secure the front cover 5 and the rear cover 3;

[0063] The membrane 7 is a flexible structure that wraps the front cover 5, the upper sensor array 1, the lower sensor array 2, the rear cover 3, and the tail rod 8, protecting them from bodily fluid corrosion.

[0064] Furthermore, the upper sensor array 1 consists of an elastic sensor 1-E and four grating strings, namely the first grating string 1-F1 to the fourth grating string 1-F4.

[0065] The elastic sensor 1-E has a double-sided structure connected in the middle by a thin plate 1-P. Thirteen semi-racetrack-shaped protrusions are arranged equidistantly on the upper and lower parts of the front side, namely the upper first protrusion 1-BA01 to the upper thirteenth protrusion 1-BA13, and the lower first protrusion 1-BB01 to the lower thirteenth protrusion 1-BB13. Twelve T-shaped cantilever beams are arranged equidistantly in the middle, namely the first cantilever beam 1-T01 to the twelfth cantilever beam 1-T12. The first T-shaped cantilever beam 1-T01 consists of a transverse structure 1-T0101 and a vertical structure 1-T0102, which are perpendicular to each other. The rear section of the transverse structure 1-T0101 of the first T-shaped cantilever beam 1-T01 is connected to the thin plate 1-P, and a gap is set between the suspended section and the thin plate 1-P. The lower end of the vertical structure 1-T0102 of the first T-shaped cantilever beam 1-T01 has an arc-shaped transition structure with a circular groove for fixing the grating string; this is called the lower transition structure. Its upper end is a cuboid structure, with the top end contacting the coating to transmit force. The middle part is open and has an arc-shaped transition structure with a circular groove for fixing the grating string; this is called the upper transition structure. The vertical structure 1-T0102 of the first T-shaped cantilever beam 1-T01 is located between bosses 1-BA01 and 1-BA02, and its transverse structure 1-T0101 is located between bosses 1-BA02 and 1-BB02. The structures of the second T-shaped cantilever beam 1-T02 to the twelfth T-shaped cantilever beam 1-T12 are the same as the first T-shaped cantilever beam 1-T01, and their arrangement follows the same pattern. The tops of the equidistantly arranged vertical structures of the T-shaped cantilever beams are used to contact the object being measured; these are called contact points. The rear structure of the elastic sensor is the same as the front structure, but the positions of its boss and cantilever beam structure are shifted compared to the front, so that the first cantilever beam on the rear side is located in the middle of the first cantilever beam and the second cantilever beam on the front side, and the position of the boss is also in the same way.

[0066] Each cantilever beam consists of a horizontal structure (lever arm) and a vertical structure (contact points and grating fixing platform) arranged vertically. One end of the horizontal structure is fixed to a thin plate, while the other end is suspended, forming a typical cantilever beam mechanical model where the pressure-deflection relationship can be accurately calculated. The vertical structure has arc-shaped transition structures and circular grooves at its upper and lower ends to fix the upper and lower grating strings. This design ensures that under a single pressure, the upper surface of the cantilever beam experiences tensile strain, and the lower surface experiences compressive strain, thereby driving the upper and lower gratings to produce axial strains of equal magnitude but opposite directions. This not only provides a structural basis for differential temperature compensation but also doubles the pressure sensitivity. In other words, the T-shaped cantilever beam structure achieves efficient force-strain conversion and differential arrangement of the two gratings.

[0067] Secondly, 12 T-shaped cantilever beams are set on both the front and rear sides of the elastic sensor. The position of the rear cantilever beam is shifted forward by half a center distance relative to the front cantilever beam, so that the rear cantilever beam is exactly in the middle of the two adjacent front cantilever beams. Along the length of the sensor, the 12 measuring points on the front and 12 on the rear are arranged alternately, reducing the effective spacing between measuring points to half the center distance of the cantilever beams, thus doubling the equivalent spatial resolution. This design significantly improves the precision of pressure distribution measurement without increasing the number of cantilever beams, and is especially suitable for detecting pelvic floor tissue damage areas with large local pressure gradients. In other words, the staggered arrangement of the front and rear sides doubles the spatial resolution.

[0068] Furthermore, the bosses and cantilever beams are arranged in a staggered spatial configuration: the vertical structure is located between two adjacent bosses on the left and right, while the horizontal structure is located between two rows of bosses on the top and bottom. This "embedded" layout allows the cantilever beams and grating fixing points to be densely arranged within a limited length, reducing the center distance between adjacent cantilever beams to less than 5mm, while ensuring that the suspension section length of each grating is consistent and the strain transmission path is clear. Compared to the traditional design that separates the cantilever beams and fixing points, this invention significantly improves the space utilization of the sensor.

[0069] There are four grating strings, with single-mode optical fiber as the substrate. They are the first grating string 1-F1 to the fourth grating string 1-F4. The first grating string 1-F1 has twelve gratings etched at equal intervals, namely the first grating 1-F101 to the twelfth grating 1-F112. The center wavelengths of the reflection spectra of the twelve gratings are in an arithmetic sequence. The grating spacing is the sum of the distances between the semi-racetrack-shaped protrusion of the elastic sensor, the circular groove of the T-shaped cantilever beam, and the semi-racetrack-shaped protrusion. The second grating string 1-F2 to the fourth grating string 1-F4 have the same structure as the first grating string 1-F1, and the center wavelengths of the reflection spectra of the gratings at the same positions are the same.

[0070] The design achieves the following effect: the center wavelengths of the twelve gratings on each grating string are arranged in an arithmetic sequence, allowing a single optical fiber to carry the signals of 12 sensing units simultaneously without interference. The four grating strings, totaling 48 sensing units, require only four optical fibers, significantly reducing the number of probe pigtails, lowering the channel requirements of the demodulation system, and facilitating probe miniaturization and clinical ease of operation.

[0071] Secondly, the grating etching spacing is designed to be the sum of the distances between the "semi-racetrack-shaped boss – T-shaped cantilever beam circular groove – semi-racetrack-shaped boss," ensuring that each grating is precisely located in the suspension section between two fixed points, thus preventing the grating from being glued in place and losing its strain response capability. Simultaneously, this design ensures that the deformation of each cantilever beam can be independently and accurately transmitted to the corresponding grating, eliminating crosstalk between measurement points.

[0072] Furthermore, the second to fourth grating strings have identical geometric parameters to the first grating string, and the center wavelengths of the gratings at the same positions are equal. This ensures that the two gratings (such as 1-F101 and 1-F201) corresponding to the same cantilever beam in the upper and lower sensing arrays have completely identical temperature response characteristics (thermal expansion coefficient, thermo-optic coefficient, initial wavelength). When the ambient temperature changes, both produce equal wavelength shifts, which cancel each other out after subtraction; simultaneously, their strain responses to pressure are equal in magnitude but opposite in sign due to the symmetrical arrangement of the cantilever beams, resulting in doubled pressure signal output after subtraction. Without this "same wavelength" characteristic, perfect differential noise cancellation cannot be achieved, and the temperature self-compensation effect will be significantly reduced.

[0073] The first grating string 1-F1 is suspended between the upper boss of the elastic sensor and the upper arc-shaped transition structure of the vertical structure of the T-shaped cantilever beam. The second grating string 1-F2 is suspended between the lower boss of the elastic sensor and the lower arc-shaped transition structure of the vertical structure of the T-shaped cantilever beam, with the gratings positioned in the fiber suspension section. Specifically: the first grating string 1-F101 is located between the upper first boss 1-BA01 and the upper transition structure of the vertical structure of the first T-shaped cantilever beam 1-T0102, with the left pigtail fixed to the upper first boss 1-BA01 and the right pigtail fixed to the upper second boss 1-BA02; the second grating string 1-F201 is located between the upper and lower boss 1-BB01 and the lower transition structure of the vertical structure of the first T-shaped cantilever beam 1-T0102, with the left pigtail fixed to the lower first boss. 1-BB01, the right side pigtail is fixed to the lower second boss 1-BB02; these structures constitute the first sensing unit S01, and the center wavelengths of the first grating string first grating 1-F101 and the second grating string first grating 1-F201 are equal. The structures and positions of the second sensing unit S02 to the twelfth sensing unit S12 are similar. The rear boss and cantilever beam, the third grating string 1-F3, and the fourth grating string 1-F4 constitute the thirteenth sensing unit S13 to the twenty-fourth sensing unit S24.

[0074] In this design, the fiber Bragg grating is suspended between the boss and the cantilever beam transition structure, fixed at both ends and suspended in the middle, with the grating segment not in contact with any solid. This design allows the bending deformation of the cantilever beam to be converted into axial strain of the fiber almost without loss, achieving a strain transfer efficiency close to 100%, far exceeding that of embedding the grating inside the elastic sensor 1-E or surface bonding. Simultaneously, it avoids pre-strain or zero-point drift caused by adhesive curing shrinkage, aging, or creep, ensuring measurement stability during long-term use. The suspended fixing achieves efficient strain transfer, guaranteeing measurement accuracy.

[0075] Secondly, a grating (1-F101 and 1-F201) is suspended and fixed on the upper and lower sides of each cantilever beam, respectively, with both having the same initial center wavelength. Under pressure, the upper grating generates positive strain (wavelength drift towards longer wavelengths), and the lower grating generates negative strain (wavelength drift towards shorter wavelengths). The wavelength drift caused by pressure is equal in magnitude and opposite in sign; when the temperature changes, both generate completely equal wavelength drifts (in the same direction). After subtracting the wavelength drifts of the two, the temperature contribution completely cancels out, and the pressure contribution is added to the output (sensitivity is doubled). This mechanism requires no additional temperature sensor or compensation circuit; temperature self-compensation can be achieved solely through structural design. The symmetrical suspension at the top and bottom forms a differential pair, achieving both temperature self-compensation and a doubling of sensitivity.

[0076] Furthermore, the 12 measuring points on the front (S01-S12) and the 12 measuring points on the rear (S13-S24) are staggered, with the rear cantilever beam located in the middle of the two adjacent front cantilever beams. This arrangement reduces the effective spacing between measuring points along the sensor's length to half the center distance of the cantilever beams, doubling the spatial resolution and avoiding pressure measurement blind spots between adjacent measuring points. It also provides higher detection capability for tissues with large local pressure gradients (such as areas of pelvic floor muscle injury). The staggered double-row arrangement doubles the spatial resolution.

[0077] Furthermore, the corresponding gratings in the first grating string 1-F1 and the second grating string 1-F2 have the same initial center wavelength (e.g., the wavelengths of 1-F101 and 1-F201 are equal). This is a necessary prerequisite for achieving perfect differential cancellation through temperature self-compensation: only when the initial wavelengths are equal will the wavelength shift caused by temperature be strictly equal; if the wavelengths are different, even if the temperature change is the same, the shift will differ and cannot be completely cancelled. The wavelength matching design of this invention ensures the accuracy of temperature self-compensation. The equal center wavelengths of the upper and lower gratings provide a necessary condition for differential compensation.

[0078] Furthermore, the lower sensing array 2 is configured in the same way as the upper sensing array 1, with both structures being mirror-symmetrical about the horizontal plane and arranged back to back; the lower sensing array 2 has the twenty-fifth sensing unit S25 to the forty-eighth sensing unit S48; the sensing units of the upper sensing array 1 point upwards from the sensor, and the sensing units of the lower sensing array 2 point downwards from the sensor; when the two are combined, a semi-racetrack-shaped protrusion is formed at the upper and lower parts of the overall structure, and a racetrack-shaped protrusion is formed in the middle of the structure.

[0079] By arranging two identical, mirror-symmetrical sensor arrays back-to-back, with the sensing units pointing towards the upper and lower sides of the sensor respectively, the sensor can simultaneously measure the local tissue pressure distribution on both sides of a body cavity (such as the anterior and posterior walls of the vagina) after a single insertion. The upper sensor array provides 24 measurement points (S01-S24), and the lower sensor array provides another 24 measurement points (S25-S48), for a total of 48 measurement points, doubling the number compared to existing single-sided probes. Furthermore, it eliminates the need for rotation or repeated insertion and removal, significantly shortening examination time and reducing patient discomfort. Dual-sided synchronous measurement and doubled measurement points significantly improve clinical efficiency.

[0080] Secondly, after the upper and lower sensor arrays are bonded together, semi-racetrack-shaped protrusions naturally form on their upper and lower surfaces, and a complete racetrack-shaped protrusion forms on the middle contact surface. These protrusions and corresponding grooves on the front and rear covers (semi-racetrack-shaped groove 303 on the rear cover, racetrack-shaped groove 302, and corresponding displacement groove on the front cover) form a mechanical interlock, achieving six-degree-of-freedom precise positioning of the sensor array within the housing. Simultaneously, the racetrack-shaped protrusions increase the bonding area between the upper and lower sensor arrays, and with adhesive bonding, they can withstand repeated pressure loading for extended periods without relative slippage or loosening. This ensures that the spatial coordinates of each sensing unit remain consistent across multiple uses, maintaining the repeatability and accuracy of multi-point measurements. The protrusion-groove mating structure ensures the precise positioning and long-term stability of the sensor array.

[0081] Furthermore, the rear cover 3 is a thin-shell structure, with the front section being a semi-circular thin-walled structure and a stepped hole 301 in the middle; the middle section is a rectangular thin-walled structure with semi-racetrack-shaped grooves 303 arranged on its upper and lower sides and a racetrack-shaped groove 302 arranged in its middle, the position of which corresponds to the position of the rear boss after the upper elastic sensor array 1 and the lower sensor array 2 are engaged; the rear section is a trapezoidal thin-shell structure.

[0082] Furthermore, the front cover 5 has the same structure as the rear cover 3, but its semi-racetrack and racetrack-shaped grooves are slightly displaced compared to the rear cover. Their positions correspond to the positions of the front protrusions after the upper elastic sensor and the lower sensor are engaged. After the front cover 5 and the rear cover 3 are engaged, they form a hollow structure that houses and supports the sensor array.

[0083] Furthermore, the tail rod 8 is a stepped cylindrical structure. The shape and size of the front end match the shape and size of the front cover 5 and the rear cover 3 after they are fitted together. After they are fitted together, they form a relatively closed structure to support the overall structure of the sensor. The tail fiber of the grating string is arranged inside it.

[0084] Furthermore, the coating 7 is a flexible thin film structure, made of flexible hydrogel material by molding. The shape and size of its inner wall match the shape and size of the outer wall of the structure formed by the front cover 5 and the rear cover 3. Square protrusions are arranged on the upper and lower parts of the inner wall. Their number and position correspond to the number and position of the sensing array sensing units, namely the first square protrusion 7-A01 to the twelfth square protrusion 7-A12 on the upper front side, the first square protrusion 7-B01 to the twelfth square protrusion 7-B12 on the upper rear side, and the square protrusions at the corresponding positions on the lower side.

[0085] In this design, square protrusions are positioned one-to-one with the sensor array on the inner wall of the membrane. Each protrusion independently transmits external pressure to its corresponding cantilever beam contact point, concentrating the pressure at the top of the cantilever beam and preventing it from diffusing to adjacent measurement points on the membrane surface. Actual measurements show that this design results in a crosstalk rate of less than 3% between adjacent measurement points, ensuring spatial resolution and measurement point independence for multi-point distributed measurements, and avoiding the pressure averaging problem caused by traditional airbag or full-contact membrane designs. Precise local pressure transmission guarantees the spatial resolution of multi-point measurements.

[0086] Secondly, both the upper and lower surfaces of the membrane are provided with protrusions, corresponding to the upper sensor array (S01-S24) and the lower sensor array (S25-S48), respectively. After the sensor is inserted into the human cavity, it can simultaneously measure the pressure distribution of the anterior and posterior (or lateral) walls of the vagina, obtaining multi-directional mechanical information in a single examination. This eliminates the need to rotate the probe or repeat insertion, significantly shortening the examination time and reducing patient discomfort.

[0087] Furthermore, the front cover 5, rear cover 3, elastic sensor 1-E, and tail rod 8 are all manufactured using photopolymerization 3D printing. The upper sensor array 1 and lower sensor array 2 are then assembled according to the above method. The front cover 5 and rear cover 3 are fixed in the middle, and the fastening nut 4 and fastening screw 6 are fixed together through the stepped hole 301, and then connected and fixed to the tail rod 8. Connections not mentioned above are completed using adhesive.

[0088] In this invention, the front cover, rear cover, elastic sensor, and tail rod are all integrally formed using photopolymerization 3D printing, eliminating the need for complex assembly processes, resulting in high manufacturing precision and controllable costs. The T-shaped cantilever beam and boss-assisted grating suspension design ensures more reliable tensioning and positioning of the grating string, making it suitable for mass production. Furthermore, the overall structure is compact (only a few centimeters wide), adapting to the integration needs of small-sized medical devices such as transvaginal probes. The compact structure facilitates miniaturization and mass production.

[0089] Furthermore, the membrane utilizes its inherent flexibility to encapsulate the aforementioned formed sensor structure, creating a sealed and waterproof structure. The first square protrusion 7-A01 to the twelfth square protrusion 7-A12 on the upper front side correspond to the positions of the first sensing unit S01 to the twelfth sensing unit S12, respectively; the first square protrusion 7-B01 to the twelfth square protrusion 7-B12 on the upper rear side correspond to the positions of the thirteenth sensing unit S13 to the twenty-fourth sensing unit S24, respectively; and the lower square protrusions correspond to the positions of the twenty-fifth sensing unit S25 to the forty-eighth sensing unit S48, and so on. This membrane structure design, on the one hand, protects the internal fiber optic grating and elastic sensor through sealing and waterproofing, enabling the sensor to be used safely and reliably in humid environments within the body; on the other hand, the precise correspondence between the inner wall protrusions and each sensing unit ensures the independence and accuracy of pressure transmission, avoiding crosstalk problems in multi-point measurements, and also maintains the symmetry of the cantilever beam's stress deformation, providing external protection for the normal operation of the temperature self-compensation mechanism.

[0090] It should be noted that this invention suspends two grating strings symmetrically on the upper and lower sides of each T-shaped cantilever beam. Temperature changes cause the same wavelength shift in both gratings, while pressure causes the opposite wavelength shift. The difference between the wavelength shifts of the two gratings is calculated; the temperature contributions cancel each other out, and the pressure contributions are added together for output, thus achieving a self-compensating, temperature-insensitive pressure measurement. Specifically:

[0091] A temperature-compensated multi-point distributed measurement method for local tissue pressure in the human body, wherein:

[0092] S1. When the sensor comes into contact with local tissue of the human body, the pressure is transmitted to the T-shaped cantilever beam through the membrane 7. The sensing units S01 to S48 of the upper sensing array 1 and the lower sensing array 2 measure the pressure and express it in Newtons.

[0093] S2. Taking the first sensing unit S01 as an example, under pressure, the transverse structure 1-T0101 of the T-shaped cantilever beam 1-T01 undergoes bending deformation, causing the first grating string 1-F1 to experience positive strain and the second grating string 1-F2 to experience reverse strain. This results in equal and opposite shifts in the center wavelengths of the reflection spectra of gratings 1-F101 and 1-F201 at two corresponding positions. By analyzing the mechanical model of the cantilever beam, the deflection at the front end of the cantilever beam under pressure is obtained. Then, the strain of the fiber optic grating is calculated by combining geometric relationships. Furthermore, the mathematical relationship between pressure and wavelength shift is obtained by combining the relationship between wavelength shift and strain. By monitoring the difference in the change value of the center wavelength of the reflection spectra of gratings 1-F101 and 1-F201, multi-point distributed measurement of local tissue pressure in the human body is achieved. The measurement methods for other sensing units are similar.

[0094] S3. Based on the method described in S2, under the premise of the same temperature change, the center wavelength drift of all fiber grating reflection spectra caused by temperature is the same. The method of subtracting the center wavelength drift of the fiber grating at corresponding positions described in S2 eliminates the influence of the wavelength drift caused by temperature on the calculation results, thereby eliminating the influence of temperature change on the pressure measurement results, while improving the measurement sensitivity and realizing temperature self-compensation in the array pressure measurement process.

[0095] The core of the aforementioned measurement method lies in utilizing the differentiated response modes of temperature and pressure (same temperature response, opposite pressure response) of the gratings on both sides of the same cantilever beam, and simultaneously achieving temperature self-compensation and sensitivity multiplication through differential calculation. This method is a natural extension of the structural design of this invention (symmetrically suspended dual gratings), and the synergistic effect of the structure and method constitutes a complete temperature self-compensating array-type pressure sensing technology solution.

[0096] The working principle of the temperature self-compensating array pressure sensor based on fiber Bragg grating in this embodiment is as follows:

[0097] Taking the first sensing unit S01 as an example, see Figure 7 The T-shaped cantilever beam 1-T01 is fixed on the right side, and the distance from the left force-bearing position to the fixed end is L. Bosses 1-BA01, 1-BA02, 1-BB01, and 1-BB02 are fixed. The first grating string, grating 1-F101, is suspended between boss 1-BA01 and the upper transition structure of the T-shaped cantilever beam 1-T01. The second grating string, grating 2-F101, is suspended between boss 1-BB01 and the lower transition structure of the T-shaped cantilever beam 1-T01. The horizontal distance of the suspension section is l, the vertical distance is h, and the suspension length is s. Therefore:

[0098] (1)

[0099] Further, see Figure 8 When the upper part of the T-shaped cantilever beam 1-T01 is subjected to force, its suspended section bends. Under the action of force F, the deflection generated at the front end is w, then:

[0100] (2)

[0101] in, Let I be the elastic modulus of the cantilever beam material, and let I be the moment of inertia of the cantilever beam section. We also have:

[0102] (3)

[0103] Then we have:

[0104] (4)

[0105] Furthermore, at this time, the length of the suspension segment of the first grating string 1-F101 is... for:

[0106] (5)

[0107] Furthermore, the strain of the first grating string, the first grating 1-F101 for:

[0108] (6)

[0109] Similarly, the length of the suspension segment of the first grating 1-F201 in the second grating string can be obtained. for:

[0110] (7)

[0111] Furthermore, the strain of the second grating string connected to the first grating 1-F201 for:

[0112] (8)

[0113] According to coupled-mode theory, the shift in the center wavelength of a fiber grating under temperature and strain is as follows:

[0114] (9)

[0115] in, and These represent the center wavelength shift of the fiber grating reflection spectrum and its initial value, respectively. denoted as the optical elasticity coefficient of the optical fiber. This refers to the axial strain occurring on the fiber grating. The coefficient of thermal expansion of optical fiber. The optical fiber thermo-optic coefficient, This represents the change in ambient temperature.

[0116] Furthermore, during the measurement process, the wavelength shift of the first grating string, first grating 1-F101, is... Wavelength shift of the first grating 1-F201 in the second grating string for:

[0117] (10)

[0118] in, This represents the change in ambient temperature of the first grating string, grating 1-F101. The change in ambient temperature of the second grating string containing the first grating 2-F101 is equal to the change in ambient temperature. The initial center wavelength of the first grating string, first grating 1-F101, The initial center wavelength of the second grating string is equal to that of the first grating 2-F101, and is denoted as . .

[0119] Furthermore, the difference in wavelength drift between the first grating 1-F101 in the first grating string and the first grating 2-F101 in the second grating string is used as the output of the first sensing unit S01. :

[0120] (11)

[0121] Furthermore, we have:

[0122] (12)

[0123] Furthermore, due to Much smaller than h and l, right If we consider the sensitivity as the derivative of equation (12) at 0, then we have:

[0124] (13)

[0125] Furthermore, we have:

[0126] (14)

[0127] Furthermore, during the measurement process, the difference in center wavelength drift between the first grating 1-F101 of the first grating string and the first grating 2-F101 of the second grating string is monitored. By combining equation (14), the local tissue pressure of the human body at the first sensing unit S01 can be obtained, and the pressure at the other sensing units can be obtained in the same way.

[0128] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A temperature self-compensating array pressure sensor based on fiber Bragg gratings, characterized in that: The sensor includes a front cover, a force sensing array, a rear cover, a tail rod, fasteners, and a protective film. When the sensor is placed horizontally, the front cover and the rear cover are located on the front and rear sides of the sensor, respectively. When they are put together, they form a cavity to support and fix the force sensing array. The force sensing array consists of an upper sensing array and a lower sensing array. The upper sensing array is composed of an elastic sensor and four grating strings, with two rows of side-by-side staggered sensing units. The structure of the lower sensing array is the same as that of the upper sensing array. The sensing units of the upper sensing array point upwards from the sensor, while the sensing units of the lower sensing array point downwards from the sensor. The tail rod is located behind the sensor and is connected to the front cover and the rear cover. It is used to support the overall structure of the sensor and to arrange the fiber optic grating string. Fasteners connect and secure the front and rear covers; The coating is a flexible structure that wraps around the front cover, sensor array, rear cover and tail rod, protecting them from bodily fluid corrosion. The elastic sensor has multiple cantilever beam structures. The first and second grating strings of the four grating strings of the elastic sensor are fixed to the first and second sides of each cantilever beam structure, respectively. The first and second grating strings generate axial strains of opposite signs as the cantilever beams deform. The sensor achieves temperature self-compensation for pressure measurement by detecting the difference in wavelength shift between the corresponding gratings in the first and second grating strings.

2. The temperature self-compensating array pressure sensor based on fiber Bragg grating according to claim 1, characterized in that: The rear cover has a thin-shell structure. The front section is a semi-circular thin-walled structure with a stepped hole in the middle. The middle section is a rectangular thin-walled structure with semi-racetrack-shaped grooves on its upper and lower sides and a racetrack-shaped groove in its middle. The rear section is a trapezoidal thin-shell structure.

3. The temperature self-compensating array pressure sensor based on fiber Bragg grating according to claim 1, characterized in that: The front cover and the rear cover have the same structure, but the semi-racetrack and racetrack-shaped grooves are slightly displaced compared to the rear cover.

4. The temperature self-compensating array pressure sensor based on fiber Bragg grating according to claim 1, characterized in that: The upper sensing array consists of an elastic sensor and a string of gratings, wherein... The elastic sensor has a double-sided structure connected by a thin plate in the middle. The front side has equidistantly spaced semi-racetrack-shaped protrusions at the top and bottom, and equidistantly spaced T-shaped cantilever beams in the middle. Each T-shaped cantilever beam consists of a vertical and a horizontal structure, which are perpendicular to each other. The rear section of the horizontal structure of the T-shaped cantilever beam connects to the thin plate, and the suspended section is spaced from the thin plate. The lower end of the vertical structure of the T-shaped cantilever beam has an arc-shaped transition structure with a circular groove for fixing the grating string. Its upper end is a cuboid structure, with the top contacting the coating to transmit force. The middle section is open and has an arc-shaped transition structure with a circular groove for fixing the grating string. The vertical structure of the T-shaped cantilever beam is located between two adjacent semi-racetrack-shaped protrusions on the left and right, while its horizontal structure is located between two rows of protrusions on the top and bottom. The grating string substrate is a single-mode optical fiber, in which gratings are etched at equal intervals, and the center wavelength of the grating reflection spectrum is an arithmetic sequence; the grating spacing is the sum of the distances between the elastic sensor semi-runway-shaped boss, the T-shaped cantilever beam transition structure, and the semi-runway-shaped boss. The center wavelengths of the two grating strings at the same position are equal. They are suspended and fixed between the upper semi-racetrack-shaped boss and the upper arc-shaped transition structure of the cantilever beam, and between the lower semi-racetrack-shaped boss and the lower arc-shaped transition structure of the cantilever beam, respectively. The structure and grating string arrangement on the rear side of the elastic sensor are the same as those on the front side. The position of its semi-racetrack-shaped boss and T-shaped cantilever beam is shifted backward compared to the front side, so that the front sensing unit array and the rear sensing unit array are arranged side by side in a staggered manner.

5. The temperature self-compensating array pressure sensor based on fiber Bragg grating according to claim 1, characterized in that: The lower sensing array has the same structure as the upper sensing array and is mirror-symmetrical about the horizontal plane. The two sensing arrays are arranged back to back, forming two sensing unit arrays on the upper and lower sides of the sensor.

6. The temperature self-compensating array pressure sensor based on fiber Bragg grating according to claim 1, characterized in that: The coating is a flexible thin film structure, made of flexible hydrogel material by molding. Its inner wall shape and size match the shape and size of the outer wall of the structure formed by the front cover, rear cover and tail rod. Square protrusions are arranged on the upper and lower parts of the inner wall, and their number and position correspond to the number and position of the elastic sensor sensing unit. The coating uses its flexible characteristics to wrap the rest of the sensor structure.

7. The temperature self-compensating array pressure sensor based on fiber Bragg grating according to claim 1, characterized in that: During the sensor assembly process, the upper sensor array and the lower sensor array are fixed together by adhesive, forming a racetrack-shaped boss in the middle of the mating structure, and semi-racetrack-shaped bosses in the upper and lower parts of the structure. The boss structure cooperates with the groove structure in the front cover and the rear cover to fix the sensor array.

8. The temperature self-compensating array pressure sensor based on fiber Bragg grating according to claim 1, characterized in that: The fasteners are standard screws and nuts, which fix the front and rear covers together at the stepped holes at the front end of the cover.

9. A monitoring method using a temperature self-compensating array pressure sensor based on a fiber Bragg grating as described in any one of claims 1-8, characterized in that: The method includes the following steps: S1. The flexible membrane of the sensor is brought into contact with local human tissue. The pressure is transmitted through the membrane to the T-shaped cantilever beam contact inside the sensor, and the pressure signal is collected by the sensing array sensing unit arranged above and below. S2. Under pressure, the T-shaped cantilever beam undergoes bending deformation, causing the fiber optic gratings suspended above and below within the same sensing unit to generate positive and negative strains respectively, resulting in equal and opposite shifts in the center wavelength of the corresponding grating reflection spectrum. By monitoring the difference in the center wavelength shift of the corresponding gratings above and below within the same sensing unit, and combining the cantilever beam mechanical model, geometric relationships, and fiber optic grating strain-wavelength shift relationship, the multi-point pressure values ​​of local tissues in the human body can be calculated. S3. Temperature changes cause equal and same wavelength drift in the upper and lower gratings within the same sensing unit. By calculating the wavelength drift difference in step S2, the interference of temperature-induced wavelength drift on the pressure calculation results is eliminated, thus realizing temperature self-compensation and multi-point distributed pressure measurement.

10. The monitoring method of the temperature self-compensating array pressure sensor based on fiber Bragg grating according to claim 9, characterized in that: By calculating the wavelength drift difference, temperature self-compensation is achieved while pressure measurement sensitivity is improved; the initial center wavelengths of corresponding gratings in the same sensing unit are equal, ensuring consistent temperature drift and opposite pressure strain drift.

Images