A tri-axial TMR array pressure sensing device

Abstract

The application relates to the field of pressure sensors and discloses a three-axis TMR array type pressure sensing device, which comprises a cylindrical medium isolation cavity, the open end of the cylindrical medium isolation cavity is provided with an elastic wave corrugated pressure sensing diaphragm, the cavity is divided into a medium end to be measured and a sealed reference cavity, a magnetic field generating unit with a magnetic shaft fixed in the center of the diaphragm is perpendicular to the diaphragm, the magnetic field generating unit is synchronously displaced along with the axial deformation of the diaphragm, pressure change is converted into spatial magnetic field vector displacement, a three-axis TMR sensing unit is arranged on the bottom wall of the cavity, the three-axis TMR sensing unit comprises a central measurement sensor and a plurality of auxiliary measurement sensors which are uniformly distributed in the circumferential direction, the central measurement sensor is coaxial with the magnetic field generating unit, an adaptive vector decoupling processor is electrically connected with each sensor, magnetic field and temperature data are synchronously received, and a pressure value is output through vector decoupling. The device is suitable for various medium pressure detection scenes and has high measurement precision and environmental adaptability through the conversion mechanism of the magnetic field-displacement-pressure and the array type sensing and adaptive decoupling design.

Description

Technical Field

[0001] This invention relates to the field of pressure sensor technology, and more specifically to a triaxial TMR array pressure sensing device. Background Technology

[0002] Pressure sensors are core sensing components in industrial measurement and control, precision instruments, aerospace, and medical equipment systems. They primarily convert pressure physical quantities into processable electrical signals, and their detection accuracy, environmental stability, and adaptability to operating conditions directly impact the overall system performance. In applications requiring micro-pressure detection, high-precision measurement, and complex operating conditions, traditional piezoresistive and capacitive pressure sensors are no longer sufficient. Existing magnetic pressure sensing devices typically use pressure-sensitive diaphragms combined with magnetic elements to achieve pressure signal conversion, but these still have several shortcomings in practical applications.

[0003] In micro-pressure measurement scenarios, the deformation of the pressure-sensitive diaphragm is weak, and the signal acquisition capability of conventional single-point magnetic sensing structures is limited. The weak effective signal is easily masked by noise, making it difficult to achieve high-precision micro-pressure detection. In complex environments such as vibration and acceleration, the pressure-sensitive diaphragm is prone to offset or deformation in directions other than the measurement direction. Conventional sensing structures struggle to distinguish between effective deformation and interference deformation, easily causing fluctuations in measurement results and poor detection stability. Furthermore, the cavity structure and diaphragm material of existing sensing devices are mostly specialized designs, limiting their compatibility with different media such as gases and liquids, resulting in low versatility. In addition, existing magnetic sensing arrays have limited ability to suppress magnetic field interference, making it difficult to guarantee sensor placement accuracy and signal detection consistency, further affecting overall detection accuracy and reliability.

[0004] In summary, existing pressure sensing technologies generally suffer from insufficient sensitivity in detecting micro-pressure, poor anti-interference and environmental stability, limited adaptability to multiple media, and limited detection accuracy due to unreasonable array structure layout. Summary of the Invention

[0005] The purpose of this invention is to provide a triaxial TMR array pressure sensing device to solve the technical problems in existing pressure sensing technologies, such as insufficient sensitivity for micro-pressure detection, poor anti-interference and environmental stability, limited universal adaptability to multiple media, and limited detection accuracy due to unreasonable array structure layout.

[0006] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0007] A triaxial TMR array pressure sensing device includes:

[0008] The medium-isolated cavity has a cylindrical structure, with one end of the cylindrical structure being open;

[0009] An elastic corrugated pressure-sensitive diaphragm is disposed at the open end of the medium isolation cavity, dividing the medium isolation cavity into a measured medium end and a sealed reference cavity. The outer surface of the elastic corrugated pressure-sensitive diaphragm contacts the measured medium, and the elastic corrugated pressure-sensitive diaphragm is configured to undergo axial deformation in response to changes in the pressure of the measured medium. The sealed reference cavity is configured to provide a standard measurement environment.

[0010] A magnetic field generating unit is fixed at the center of the inner surface of the elastic corrugated pressure-sensitive diaphragm located in the sealed reference cavity. The magnetic axis of the magnetic field generating unit is configured to be perpendicular to the elastic corrugated pressure-sensitive diaphragm, and the magnetic field generating unit generates spatial displacement synchronously with the deformation of the elastic corrugated pressure-sensitive diaphragm, converting the pressure change generated by the measured medium acting on the elastic corrugated pressure-sensitive diaphragm into the displacement change of the spatial magnetic field vector.

[0011] A triaxial TMR sensing unit is disposed on the bottom wall of a dielectric isolation cavity. The triaxial TMR sensing unit includes a central measuring sensor and multiple auxiliary measuring sensors. The multiple auxiliary measuring sensors are evenly arranged around the central measuring sensor. The central measuring sensor is coaxial with the magnetic field generating unit.

[0012] An adaptive vector decoupling processor is electrically connected to the central measuring sensor and multiple auxiliary measuring sensors, and synchronously receives magnetic field data and temperature data collected by the central measuring sensor and multiple auxiliary measuring sensors, and outputs pressure values ​​after vector decoupling.

[0013] As a preferred embodiment of the present invention, the triaxial TMR sensing unit includes a PCB substrate, and the central measuring sensor and a plurality of auxiliary measuring sensors are disposed on the upper surface of the PCB substrate. The sensing surfaces of the central measuring sensor and all auxiliary measuring sensors are parallel to the surface of the PCB substrate and are aligned with the magnetic axis direction of the magnetic field generating unit.

[0014] As a preferred embodiment of the present invention, a TMR reference sensing unit is provided on the lower surface of the PCB substrate. The TMR reference sensing unit also includes a central measurement sensor and multiple auxiliary measurement sensors, and is coaxially aligned with the central measurement sensor and auxiliary measurement sensors of the triaxial TMR sensing unit in the XY plane.

[0015] As a preferred embodiment of the present invention, the central measurement sensor and auxiliary measurement sensor of the triaxial TMR sensing unit and the TMR reference sensing unit all have built-in temperature detection modules, and all the central measurement sensor, auxiliary measurement sensor and temperature detection modules are configured to synchronously output detection data.

[0016] As a preferred embodiment of the present invention, a vacuum / pressurization interface is provided on the side surface of the sealed reference cavity. The vacuum / pressurization interface is connected to the inside of the sealed reference cavity. The sealed reference cavity is used to evacuate the inside of the sealed reference cavity to form an absolute pressure reference reference during packaging, or to fill it with a standard pressure medium to form a differential pressure reference reference, so that the inside of the sealed reference cavity forms a standard measurement environment.

[0017] As a preferred embodiment of the present invention, the magnetic field generating unit adopts an axially magnetized permanent magnet, the magnetic axis of the permanent magnet is perpendicular to the elastic corrugated pressure-sensitive diaphragm, and is on the same central axis as the central measuring sensor;

[0018] The permanent magnet includes any one of neodymium iron boron micromagnets, ferrite micromagnets, samarium cobalt micromagnets (SmCo), or aluminum nickel cobalt (Alnico) micromagnets.

[0019] As a preferred embodiment of the present invention, the magnetic field generating unit is configured such that within the axial deformation range of the elastic corrugated pressure-sensitive diaphragm, all the central measuring sensors and all the auxiliary measuring sensors are in the linear magnetic field detection range.

[0020] As a preferred embodiment of the present invention, the elastic corrugated pressure-sensitive diaphragm is selected from beryllium bronze corrugated diaphragm, stainless steel corrugated diaphragm, or polytetrafluoroethylene coated / Hastelloy corrugated diaphragm according to the measurement conditions.

[0021] As a preferred embodiment of the present invention, decoupling capacitors are connected in parallel at the power supply pins of all central measurement sensors and all auxiliary measurement sensors to filter out power supply noise.

[0022] The signal pins and temperature pins of all central measurement sensors and all auxiliary measurement sensors are connected to the synchronous signal acquisition terminal of the adaptive vector decoupling processor.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] This invention employs a five-unit triaxial magnetic sensing array arranged symmetrically on both sides of a PCB substrate, consisting of a dielectric isolation cavity, an elastic corrugated pressure-sensitive diaphragm, a miniature permanent magnet, and an adaptive vector decoupling processor, to form an overall pressure sensing device. This device can significantly improve the sensitivity and accuracy of micro-pressure detection, effectively suppress common-mode interference caused by vibration, acceleration, background magnetic field, and temperature drift, and achieve hardware-level separation of effective pressure signals and interference signals.

[0025] The five-unit square arrangement on the front side disclosed in this invention can simultaneously collect magnetic field vectors at multiple points in space, accurately distinguishing between axial pressure deformation and lateral and tilting interference deformation; the coaxial paired reference array on the back side and the front array are in the same sealed reference cavity environment, forming a symmetrical differential structure, which can significantly eliminate common-mode noise and zero-point drift.

[0026] The sealed reference chamber disclosed in this invention provides a stable reference standard by evacuating or filling with standard pressure, taking into account both absolute pressure and differential pressure measurement modes. Combined with a replaceable diaphragm and a universal isolation chamber design, it achieves stable adaptation to multiple media and multiple measurement ranges of gas and liquid. Attached Figure Description

[0027] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0028] Figure 1 This is a cross-sectional structural diagram of the pressure sensing device according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the planar topology of a five-element paired reference array according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the overall structure of the pressure sensing device according to an embodiment of the present invention.

[0031] The labels in the diagram represent the following:

[0032] 1-Dielectric isolation cavity; 2-Elastic corrugated pressure-sensitive diaphragm; 3-Measured medium end; 4-Sealed reference cavity; 5-Magnetic field generating unit; 6-Triaxial TMR sensing unit; 61-Center measurement sensor; 62-Auxiliary measurement sensor; 63-PCB substrate; 7-TMR reference sensing unit. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] like Figure 1 , Figure 2 and Figure 3As shown, this embodiment provides a three-axis TMR array pressure sensing device, which is a general-purpose precision pressure sensing structure compatible with multiple media such as gas and liquid, and is particularly suitable for ultra-precision pressure detection in environments with low pressure, strong vibration, and strong interference.

[0035] Specifically, it includes: a dielectric isolation cavity, an elastic corrugated pressure-sensitive diaphragm, a magnetic field generating unit, a triaxial TMR sensing unit, and an adaptive vector decoupling processor. Among these,

[0036] The medium isolation cavity 1 has a cylindrical structure, with one end of the cylindrical structure being open;

[0037] An elastic corrugated pressure-sensitive diaphragm 2 is disposed at the open end of the medium isolation cavity 1. The elastic corrugated pressure-sensitive diaphragm 2 divides the medium isolation cavity 1 into the measured medium end 3 and the sealed reference cavity 4. The outer surface of the elastic corrugated pressure-sensitive diaphragm 2 contacts the measured medium, and the elastic corrugated pressure-sensitive diaphragm 2 is configured to undergo axial deformation in response to changes in the pressure of the measured medium. The sealed reference cavity 4 is configured to provide a standard measurement environment.

[0038] The magnetic field generating unit 5 is fixed to the center of the inner surface of the elastic corrugated pressure-sensitive diaphragm 2 located in the sealed reference cavity 4. The magnetic axis of the magnetic field generating unit 5 is configured to be perpendicular to the elastic corrugated pressure-sensitive diaphragm 2, and the magnetic field generating unit 5 generates spatial displacement synchronously with the deformation of the elastic corrugated pressure-sensitive diaphragm 2, converting the pressure change generated by the measured medium acting on the elastic corrugated pressure-sensitive diaphragm 2 into the displacement change of the spatial magnetic field vector.

[0039] The triaxial TMR sensing unit 6 is disposed on the bottom wall of the medium isolation cavity 1. The triaxial TMR sensing unit 6 includes a central measuring sensor 61 and multiple auxiliary measuring sensors 62. The multiple auxiliary measuring sensors 62 are evenly arranged around the central measuring sensor 61. The central measuring sensor 61 is coaxial with the magnetic field generating unit 5.

[0040] The adaptive vector decoupling processor is electrically connected to the central measuring sensor 61 and multiple auxiliary measuring sensors 62, and synchronously receives magnetic field data and temperature data collected by the central measuring sensor 61 and multiple auxiliary measuring sensors 62, and outputs pressure value after vector decoupling.

[0041] In this embodiment, a five-unit measurement array consisting of a central measurement sensor 61 and four auxiliary measurement sensors 62 is used as an example.

[0042] The triaxial TMR sensing unit 6 includes a PCB substrate 63. A central measuring sensor 61 and four auxiliary measuring sensors 62 are disposed on the upper surface of the PCB substrate 63. The sensing surfaces of the central measuring sensor 61 and all the auxiliary measuring sensors 62 are parallel to the surface of the PCB substrate 63 and are aligned with the magnetic axis direction of the magnetic field generating unit 5.

[0043] A TMR reference sensing unit 7 is provided on the lower surface of the PCB substrate 63. The TMR reference sensing unit 7 also includes a central measurement sensor and multiple auxiliary measurement sensors. Taking a five-unit paired reference array consisting of a central measurement sensor and four auxiliary measurement sensors as an example.

[0044] A five-element measurement array and a five-element pairing reference array are provided. The five-element measurement array is mounted on the front side of the PCB substrate 63, and the five-element pairing reference array is mounted on the back side of the PCB substrate 63.

[0045] Among them, the five-element measurement array and the five-element paired reference array form a symmetrical differential structure through coaxial alignment, so that the common-mode interference is in the same direction and equal in value, thereby realizing the separation and suppression of the effective pressure signal and the common-mode interference signal;

[0046] The adaptive vector decoupling processor is electrically connected to both the five-element measurement array and the five-element paired reference array. It synchronously receives magnetic field and temperature data collected by the five-element measurement array and the five-element paired reference array, and outputs the pressure value after vector decoupling.

[0047] This implementation improves pressure detection sensitivity, anti-interference capability, and multi-condition adaptability from a hardware perspective by using a five-unit triaxial TMR sensor array hardware design with symmetrical front and back sides, combined with a universal dielectric isolation cavity, an elastic corrugated pressure-sensing diaphragm adaptable to multiple working conditions, and a highly stable magnetic-elastic coupling structure.

[0048] In this embodiment, the elastic corrugated pressure-sensitive diaphragm 2 divides the medium isolation cavity 1 into the measured medium end 3 and the sealed reference cavity 4 and achieves sealing isolation. On the one hand, it can physically isolate the measured medium from the precision sensing element inside the sealed reference cavity 4 to avoid corrosion and contamination. On the other hand, it provides a stable closed space for pressure-deformation-magnetic field conversion, ensuring that the magnetic-elastic coupling structure only responds to pressure changes and improves detection stability.

[0049] Selection and arrangement of the three-axis TMR sensing unit 6:

[0050] This embodiment employs a high-sensitivity triaxial tunnel magnetoresistive (TMR) sensor with a sensitivity better than 0.01 μT and a noise floor below 50 nTRMS. It incorporates a built-in temperature detection module, enabling simultaneous output of triaxial magnetic field and temperature data. The use of a triaxial TMR device allows for complete detection of the spatial magnetic field vector, providing a hardware foundation for subsequent decoupling of axial pressure signals and lateral interference signals.

[0051] The triaxial TMR sensing unit 6 uses a rigid PCB substrate as its carrier and adopts a fully symmetrical differential configuration of a five-unit measurement array combined with a five-unit paired reference array. All measurement sensors and reference sensors are selected from the same batch and model of components to ensure high consistency in sensitivity, zero drift, and temperature coefficient, so that common-mode interference can be canceled to the maximum extent in differential operation.

[0052] Establish a unified coordinate system: take the center of the sensing surface of sensor S0 at the center of the front of the PCB substrate as the origin O(0,0,0), the Z-axis is perpendicular to the PCB plane and points upward to the magnetic field generating unit 5, and is in the same direction as the magnetic axis of the magnetic field generating unit 5; the PCB thickness is a fixed value h, and the array radius a is optimized to 1~3mm according to the magnetic field gradient, so that the sensor works in the linear region and improves the linearity of magnetic field-pressure conversion.

[0053] Five-element measurement array:

[0054] The five-unit measurement array is mounted on the front side of the PCB, located within the sealed reference cavity 4, and arranged symmetrically in a regular quadrilateral shape, including:

[0055] The central measuring sensor S0 is located directly below the magnetic field generating unit 5, coaxial with the magnetic axis, and has coordinates (0,0,0). As the core detection device, it acquires the principal component of the axial magnetic field caused by pressure.

[0056] The four auxiliary measurement sensors S1~S4 are evenly distributed at the four vertices of a regular quadrilateral with S0 as the center and radius a, and their coordinates are (a,0,0), (0,a,0), (-a,0,0), and (0,-a,0) respectively. They are used to collect magnetic field vectors at multiple points in space and provide data support for identifying lateral and tilt deformation interference.

[0057] All sensor sensing surfaces are parallel to the elastic corrugated pressure-sensitive diaphragm, and the magnetic axis is aligned with the magnetic field generating unit 5, ensuring consistent magnetic field acquisition direction and avoiding calculation errors caused by vector direction deviation.

[0058] Five-cell paired reference array:

[0059] The five-unit paired reference array is mounted on the back of the PCB substrate, coaxially aligned with the front array in the XY plane, with only the Z-axis separated by the substrate thickness h, including:

[0060] Center reference sensor R0: coaxially aligned with S0, coordinates (0,0,-h);

[0061] Reference sensors R1~R4 around the perimeter: respectively coaxially aligned with S1~S4.

[0062] The XY alignment deviation between the back array and the front array is less than 0.02mm, ensuring strict coaxial symmetry in spatial position. This makes common-mode interference such as background magnetic field, temperature, and vibration present equal and symmetrical characteristics on both front and back sensors, providing structural protection for hardware-level differential interference cancellation design.

[0063] This implementation overcomes the limitation of traditional single sensors that can only collect magnetic fields at a single point. It achieves synchronous detection of magnetic fields at multiple spatial measurement points through hardware, providing fundamental data support for distinguishing between axial pressure deformation and lateral / tilt interference deformation. Based on a five-unit spatial layout, by measuring the difference in magnetic field vectors between the central measuring sensor and the surrounding auxiliary measuring sensors, it can identify and separate lateral and tilt non-pressure deformation signals caused by vibration / acceleration at the source, solving the hardware defect of traditional sensors that cannot distinguish between valid signals and interference signals.

[0064] The five-element measurement array is used to acquire the magnetic field vector signal superimposed by pressure deformation and environmental interference, while the five-element paired reference array is used to acquire the magnetic field signal without environmental interference. The two are aligned coaxially to form a symmetrical differential structure to achieve the separation and suppression of the effective pressure signal and the common-mode interference signal.

[0065] Specifically, because the front measurement array and the back reference array are coaxially symmetrical and have completely identical structures, they will sense common-mode interference (background magnetic field, temperature drift, vibration, circuit noise) of almost the same magnitude. However, only the front measurement array can sense the effective pressure signal brought about by the displacement of the permanent magnet, while the back reference array cannot sense it. Through symmetrical differential operation (front signal - back signal), the same common-mode interference is canceled out, and only the effective pressure signal is retained and amplified, thereby achieving the separation and suppression of the effective pressure signal and the common-mode interference signal.

[0066] The five-element measurement array on the front and the paired five-element reference array on the back are arranged coaxially and symmetrically. This ensures that common-mode interferences such as background magnetic field, temperature drift, and vibration noise generate equal and unidirectional signals on both the front and back sensors. The effective magnetic field signal generated by the pressure deformation of the permanent magnet only acts on the front measurement array and cannot be transmitted to the back reference array. By performing symmetrical differential processing on the two sets of signals, the equal and unidirectional common-mode interferences cancel each other out, retaining only the pressure-related effective signal. This achieves the separation and suppression of effective and interference signals at the hardware level.

[0067] Magnetic field generating unit 5 configuration:

[0068] Magnetic field generating unit 5 uses axially magnetized SmCo miniature permanent magnets, with dimensions of... The permanent magnet is fixed to the center of the inner side of the elastic corrugated pressure-sensitive diaphragm, with the magnetic axis perpendicular to the diaphragm plane. The permanent magnet moves synchronously with the diaphragm, which can accurately convert pressure deformation into changes in spatial magnetic field vector, realizing non-contact pressure detection and avoiding errors and wear introduced by mechanical contact.

[0069] The permanent magnet exhibits a temperature drift of <0.01% / ℃ and operates in a temperature range of -55℃ to +85℃, demonstrating excellent temperature stability. Combined with sensor temperature measurement data, it can achieve high-precision temperature compensation. The magnetic field strength has been optimized to ensure that the TMR sensing unit remains within the linear detection range throughout the entire process, thereby improving the accuracy and repeatability of pressure measurement.

[0070] Elastic corrugated pressure-sensitive diaphragm 2 settings:

[0071] The elastic corrugated pressure-sensitive diaphragm 2 adopts a replaceable universal design, and the material can be changed according to the medium type and measuring range.

[0072] Micro-pressure gas measurement: Beryllium bronze corrugated diaphragm is selected, and the large diameter configuration increases the deformation under micro-pressure, significantly enhancing the sensitivity of micro-pressure detection;

[0073] High-pressure gas / liquid measurement: High-modulus stainless steel corrugated diaphragm is selected to improve pressure resistance and impact resistance, and ensure linear deformation under high-pressure conditions;

[0074] Corrosive media: Use PTFE coating or Hastelloy membrane to enhance corrosion resistance and expand the range of media applicable.

[0075] The diaphragm corrugation parameters have been optimized to ensure a good linear relationship between pressure and deformation, so that the displacement of the permanent magnet remains stable within the effective detection range of TMR, avoiding signal saturation or distortion.

[0076] Medium isolation cavity 1 and sealing reference cavity 4 are set

[0077] The function of sealing the reference cavity is:

[0078] First, a fixed and unchanging pressure reference standard is established to realize absolute pressure or differential pressure measurement;

[0079] Second, it ensures that the front measurement array and the back reference array are in exactly the same environmental conditions, guaranteeing that common-mode interference is equal in value and in the same direction, and supporting the suppression of symmetrical differential interference.

[0080] Third, it isolates the measured medium from the internal magnetic sensing components to prevent corrosion and contamination;

[0081] Fourth, it provides a stable and undisturbed enclosed space to ensure that the magnetoelastic coupling conversion only responds to pressure signals, thereby improving detection accuracy and reliability.

[0082] The medium isolation chamber 1 is a split-type airtight structure, consisting of the measured medium end 3 and the sealed reference chamber 4, which are sealed and isolated by an elastic corrugated pressure-sensitive diaphragm 2.

[0083] The measured medium end 3 is equipped with a standard interface that can be adapted to threads and flanges. Anti-corrosion liners or filter components can be added to improve installation versatility and media compatibility.

[0084] The sealed reference chamber 4 is equipped with a vacuum / pressure interface, which can be used to create an absolute pressure reference by evacuating a vacuum or to create a differential pressure reference by filling with standard pressure, allowing the device to flexibly switch between absolute pressure and differential pressure measurement modes and expand its application scenarios.

[0085] The cavity is integrally laser-welded and sealed, achieving a sealing level superior to This ensures long-term stability of the reference chamber pressure and avoids reference drift affecting measurement accuracy.

[0086] The sealed cavity is free from airflow, external pressure fluctuations, and media disturbances, ensuring that the displacement of the permanent magnet is determined solely by the measured pressure and is not affected by the environment, thus guaranteeing a linear and stable magnetic field-pressure conversion.

[0087] The forward and reverse arrays of the triaxial TMR sensing unit 6 are both located inside the sealed reference cavity 4, and are in the same temperature, magnetic field and vibration environment. This ensures that the common-mode interference is highly consistent, and the symmetrical differential structure can suppress background magnetic field, temperature drift, vibration and other interference to the greatest extent, thereby improving the signal-to-noise ratio and measurement stability.

[0088] The working process of an adaptive vector decoupling processor:

[0089] The adaptive vector decoupling processor is electrically connected to the three-axis TMR sensing unit 6 to achieve integrated processing of synchronous signal acquisition, differential operation, vector decoupling, temperature compensation, and pressure output.

[0090] Synchronous acquisition: The positive and negative 10-channel triaxial magnetic field signals and temperature signals are acquired synchronously to ensure timing consistency and avoid decoupling failure caused by phase error;

[0091] Symmetrical differential: Perform differential operations on the coaxial corresponding measurement and reference sensors to directly cancel common-mode magnetic fields, temperature drift, vibration, and circuit noise, and significantly increase the proportion of effective signals;

[0092] Symmetric pairing differential scaling decoupling includes: for any pair of paired front measurement sensing units and back reference sensing units, the measured values ​​of their triaxial magnetic fields must satisfy a unified signal equation and scaling relationship.

[0093] Vector decoupling: Based on the difference in magnetic field vectors between the center and the surrounding sensors, the effective axial pressure signal and the lateral / tilt interference signal are separated at the hardware level, solving the problem that traditional structures cannot distinguish interference.

[0094] Temperature compensation: Real-time correction of temperature drift using built-in temperature measurement data to ensure stable detection accuracy over a wide temperature range;

[0095] Pressure output: Converts the decoupled and compensated magnetic field signal into a standard pressure value output, achieving accurate linear conversion from magnetic field to pressure.

[0096] Specifically, this embodiment further provides high-precision pressure calculation utilizing the multi-array TMR and adaptive decoupling of this device, specifically as follows:

[0097] All sensors of the triaxial TMR sensing unit are synchronously acquired during the operation of this device to obtain the raw triaxial magnetic field data and raw temperature data of all sensors.

[0098] Based on the original temperature data, multi-point temperature fusion calculation is performed to obtain the uniform average temperature of the entire array. The average temperature is then used to perform full-channel temperature drift compensation on the original triaxial magnetic field data to obtain temperature-compensated triaxial magnetic field data after eliminating the influence of temperature.

[0099] Using the temperature-compensated triaxial magnetic field data as input, symmetrical paired differential-proportional mapping decoupling is employed to separate the common-mode background magnetic field and the differential-mode effective magnetic field, thereby obtaining effective magnetic field data that eliminates interference from geomagnetic and environmental background magnetic fields.

[0100] Using the effective magnetic field data as input, the actual deviation of the permanent magnet is calculated based on the magnetic dipole field strength model, and the deviation error of the vertical magnetic field component in the effective magnetic field data is corrected using the actual deviation to obtain the corrected vertical magnetic field data after eliminating magnet deviation interference.

[0101] Using the corrected vertical magnetic field data as input, the array magnetic crosstalk is linearly decoupled using a pre-calibrated magnetic coupling inverse matrix to eliminate magnetic coupling interference between sensing units and obtain a pure vertical magnetic field component without multi-source interference.

[0102] The pure vertical magnetic field component is used as the sole input and substituted into a pre-calibrated polynomial fitting function to obtain a high-precision measured pressure value through mapping calculation.

[0103] In this embodiment, the full-channel temperature drift compensation is achieved by setting the temperature coefficients of the TMR sensor and the permanent magnet, with 25°C as the standard temperature, and performing unified temperature joint compensation on the raw data of all sensors in the front measurement sensing unit and the back reference sensing unit to obtain the magnetic field component after unified temperature joint compensation.

[0104] Assembly and calibration process of the pressure sensor in this embodiment

[0105] PCB assembly fabrication: SMT process is used to mount the front and back arrays, with XY alignment deviation <0.02mm. Power pins are connected in parallel with decoupling capacitors to reduce power supply noise and improve signal acquisition quality.

[0106] Magnetic-film component bonding: UV-cured permanent magnets with coaxiality deviation <0.05mm, aged at 85℃ / 12h to ensure bonding strength and long-term reliability.

[0107] Optical calibration and assembly: The permanent magnet is aligned with the central axis of the array with a alignment deviation of <0.05mm. Laser welding is used for sealing to ensure the coaxiality of the core structure and improve the consistency of testing.

[0108] Reference chamber treatment: After evacuation or filling with standard pressure, seal the chamber to establish a stable pressure reference and ensure the accuracy of absolute / differential pressure measurements.

[0109] Calibration: The coefficients are calibrated in a high-precision calibration stage and a high-low temperature chamber and written into the processor to ensure factory accuracy and wide temperature range applicability.

[0110] In this embodiment, the entire PCB substrate is installed inside the sealed reference cavity, with its front side facing the diaphragm / permanent magnet and its back side facing the bottom of the cavity (where a mating mounting groove is provided).

[0111] Both the front and rear sensors are located inside a sealed reference cavity.

[0112] Based on the above assembly and calibration process, the initial pressure offset constant can be constructed and defined. Structural stiffness constant Magnetic field sensitivity constant Initial position constant Construct the pressure to be measured With magnetic field change The relationship is as follows:

[0113] .Right now This represents the final output pressure value of the device. That is, this relationship model is built into the adaptive vector decoupling processor.

[0114] Wherein, the initial pressure offset constant (Theoretical pressure value under zero-pressure conditions, used for zero-point calibration):

[0115] .

[0116] Structural stiffness constant (Quantification of the diaphragm's inherent stiffness, reflecting the pressure-displacement ratio):

[0117] ;

[0118] Magnetic field sensitivity constant (Sensitivity to the conversion between changes in magnetic field and displacement):

[0119] ;

[0120] Initial position constant (Uniquely determined by the initial air gap):

[0121] .

[0122] in, The pressure value of the measured medium, whether absolute or differential pressure, depends on the reference of the sealed reference chamber; The elastic modulus of the elastic corrugated pressure-sensitive diaphragm material; The thickness of the elastic corrugated pressure-sensitive diaphragm; Indicates the effective working radius of the elastic corrugated pressure-sensitive diaphragm; Poisson's ratio for the elastic corrugated pressure-sensitive diaphragm material; The initial air gap is the vertical distance from the center of the permanent magnet to the sensing surface of the TMR center sensor (main sensor) under the initial zero-pressure state. This refers to the change in the axial magnetic field component detected by the TMR center sensor. , The axial magnetic field under the current pressure, The initial magnetic field is zero pressure; Expressed as vacuum permeability; The axial magnetic dipole moment is the axial magnetic dipole moment of the axially magnetized permanent magnet.

[0123] Furthermore, the temperature compensation principle of the temperature compensation module in this embodiment is as follows:

[0124] Using a five-element TMR sensor (with one central measurement sensor) Four auxiliary measurement sensors ~ ), reverse five-element TMR sensor (one central measurement sensor) Four auxiliary measurement sensors ~ All of them have built-in temperature detection modules. They adopt a multi-point temperature fusion method combined with magnet / sensor dual temperature coefficient compensation to eliminate errors caused by temperature drift. The compensation formula is derived based on the temperature characteristics of the sensor and permanent magnet.

[0125] Step 1: Calculation of average array temperature

[0126] Acquisition of frontal measurement array ~ Backside reference array ~ Measured temperature from a total of 10 sensors ( (corresponding to paired channels), calculate the average temperature of the entire array. This reduces random errors in single-point temperature detection while ensuring consistent temperature compensation standards for paired sensors.

[0127] ;

[0128] Step 2: Temperature compensation of raw magnetic field data

[0129] Let the temperature coefficient of the TMR sensor be... (Unit: % / ℃), the temperature coefficient of permanent magnets is (Unit: % / ℃), using 25℃ as the standard temperature, uniform temperature compensation was performed on the raw data of all sensors in the front measurement array and the back reference array to obtain the temperature-compensated magnetic field component. :

[0130] ;

[0131] ;

[0132] ;

[0133] in, The raw data of the triaxial magnetic field measured by the sensor; The calibration constant was determined through high and low temperature chamber experiments.

[0134] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A triaxial TMR array pressure sensing device, characterized in that, include: The medium isolation cavity (1) has a cylindrical structure, with one end of the cylindrical structure being open; An elastic corrugated pressure-sensitive diaphragm (2) is disposed at the open end of the medium isolation cavity (1). The elastic corrugated pressure-sensitive diaphragm (2) divides the medium isolation cavity (1) into a measured medium end (3) and a sealed reference cavity (4). The outer surface of the elastic corrugated pressure-sensitive diaphragm (2) contacts the measured medium, and the elastic corrugated pressure-sensitive diaphragm (2) is configured to undergo axial deformation with changes in the pressure of the measured medium. The sealed reference cavity (4) is configured to provide a standard measurement environment. The magnetic field generating unit (5) is fixed at the center of the inner surface of the elastic corrugated pressure-sensitive diaphragm (2) in the sealed reference cavity (4). The magnetic axis of the magnetic field generating unit (5) is configured to be perpendicular to the elastic corrugated pressure-sensitive diaphragm (2). The magnetic field generating unit (5) generates spatial displacement synchronously with the deformation of the elastic corrugated pressure-sensitive diaphragm (2), and the pressure change generated by the measured medium acting on the elastic corrugated pressure-sensitive diaphragm (2) is converted into the displacement change of the spatial magnetic field vector. The triaxial TMR sensing unit (6) is disposed on the bottom wall of the medium isolation cavity (1). The triaxial TMR sensing unit (6) includes a central measuring sensor (61) and multiple auxiliary measuring sensors (62). The multiple auxiliary measuring sensors (62) are evenly arranged around the central measuring sensor (61). The central measuring sensor (61) is coaxial with the magnetic field generating unit (5). The adaptive vector decoupling processor is electrically connected to the central measuring sensor (61) and multiple auxiliary measuring sensors (62), and synchronously receives magnetic field data and temperature data collected by the central measuring sensor (61) and multiple auxiliary measuring sensors (62), and outputs pressure value after vector decoupling.

2. The triaxial TMR array pressure sensing device according to claim 1, characterized in that, The triaxial TMR sensing unit (6) includes a PCB substrate (63). The central measuring sensor (61) and a plurality of auxiliary measuring sensors (62) are disposed on the upper surface of the PCB substrate (63). The sensing surfaces of the central measuring sensor (61) and all auxiliary measuring sensors (62) are parallel to the surface of the PCB substrate and are consistent with the magnetic axis direction of the magnetic field generating unit (5).

3. The triaxial TMR array pressure sensing device according to claim 1, characterized in that, A TMR reference sensing unit (7) is provided on the lower surface of the PCB substrate (63). The TMR reference sensing unit (7) also includes a central measurement sensor and multiple auxiliary measurement sensors, and is coaxially aligned with the central measurement sensor (61) and auxiliary measurement sensors (62) of the triaxial TMR sensing unit (6) on the XY plane.

4. A triaxial TMR array pressure sensing device according to claim 2, characterized in that, The central measurement sensor and auxiliary measurement sensor of the triaxial TMR sensing unit (6) and the TMR reference sensing unit (7) are all equipped with a temperature detection module. All central measurement sensors, auxiliary measurement sensors and temperature detection modules are configured to output detection data synchronously.

5. A triaxial TMR array pressure sensing device according to claim 1, characterized in that, A vacuum / pressurization interface is provided on the side surface of the sealed reference cavity (4). The vacuum / pressurization interface is connected to the inside of the sealed reference cavity (4). The sealed reference cavity (4) is used to evacuate the inside of the sealed reference cavity (4) to form an absolute pressure reference reference during packaging, or to fill it with a standard pressure medium to form a differential pressure reference reference, so that a standard measurement environment is formed inside the sealed reference cavity (4).

6. A triaxial TMR array pressure sensing device according to claim 1, characterized in that, The magnetic field generating unit (5) uses an axially magnetized permanent magnet. The magnetic axis of the permanent magnet is perpendicular to the elastic corrugated pressure-sensitive diaphragm (2) and is on the same central axis as the central measuring sensor. The permanent magnet includes any one of neodymium iron boron micromagnets, ferrite micromagnets, samarium cobalt micromagnets (SmCo), or aluminum nickel cobalt (Alnico) micromagnets.

7. A triaxial TMR array pressure sensing device according to claim 6, characterized in that, The magnetic field generating unit (5) is configured such that within the axial deformation range of the elastic corrugated pressure-sensitive diaphragm (2), all central measuring sensors and all auxiliary measuring sensors are in the linear magnetic field detection range.

8. A triaxial TMR array pressure sensing device according to claim 1, characterized in that, The elastic corrugated pressure-sensitive diaphragm (2) is made of beryllium bronze corrugated diaphragm, stainless steel corrugated diaphragm or polytetrafluoroethylene coated / Hastelloy corrugated diaphragm, depending on the measurement conditions.

9. A triaxial TMR array pressure sensing device according to claim 4, characterized in that, Decoupling capacitors are connected in parallel to the power supply pins of all central measurement sensors and all auxiliary measurement sensors to filter out power supply noise. The signal pins and temperature pins of all central measurement sensors and all auxiliary measurement sensors are connected to the synchronous signal acquisition terminal of the adaptive vector decoupling processor.

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