A pressure measuring device and method

Abstract

This application provides a pressure measurement device and method. The measurement device includes: a strain unit for receiving pressure and generating deformation; a grating projection unit for transmitting grating stripe signals to the strain unit; a camera unit for acquiring a space carrier signal, wherein the space carrier signal is a phase-modulated grating stripe signal formed by the deformation height modulation of the grating stripe projection by the strain unit; a storage unit for storing pre-calibrated P-D data, wherein the P-D data is a pre-calibrated data queue corresponding to pressure and phase difference, wherein the phase difference is the phase difference between the space carrier signal and the grating stripe signal; and a processing unit for demodulating the space carrier signal and then fitting the pre-calibrated P-D data to obtain pressure data.

Description

Technical Field

[0001] This application belongs to the field of pressure measurement technology, and specifically relates to a pressure measurement device and method. Background Technology

[0002] Traditional pressure sensors are mainly piezoresistive or capacitive pressure sensors based on the deformation of various materials. They have mature technology and excellent performance, but they require the calculation of correct height information from the phase, and the calibration of system geometric parameters and internal parameters of CCD camera and projection equipment. The calculation is complicated and the operation is inconvenient. Summary of the Invention

[0003] To address the aforementioned issues, this application provides a pressure measurement device and method that eliminates the need to calculate accurate height information from the phase, i.e., it eliminates the need to determine the correspondence between phase and height information, thus eliminating the need for calibration of system geometric parameters and the internal parameters of the CCD camera and projection equipment. This method is computationally simple, easy to operate, and significantly reduces system costs.

[0004] To achieve the above objectives, the technical solution of this application is as follows:

[0005] In a first aspect, this application provides a pressure measuring device, comprising: a strain unit for generating deformation when receiving pressure; a grating projection unit for transmitting grating stripe signals to the strain unit; a camera unit for acquiring a space carrier signal, wherein the space carrier signal is formed by the strain unit modulating the grating stripe signal according to the deformation, and the degree of distortion of the modulated space carrier signal relative to the grating stripe signal is different when the strain unit receives different magnitudes of pressure; a storage unit for storing pre-calibrated PD data, wherein the PD data includes a data queue corresponding to the pressure and the degree of distortion of the space carrier signal relative to the grating stripe signal; and a processing unit for demodulating the acquired space carrier signal to obtain the degree of distortion of the space carrier signal relative to the grating stripe signal, and then obtaining the pressure data received by the strain unit according to the pre-calibrated PD data.

[0006] In one possible implementation, the degree of distortion of the space carrier signal relative to the grating fringe signal includes at least one of the following: the phase difference of pre-calibrated local fringes in the grating fringe signal and the space carrier signal before and after deformation; the pre-calibrated local phase difference in the grating fringe signal and the space carrier signal before and after deformation being the angle between the pre-calibrated local fringes in the grating fringe signal and the space carrier signal before and after deformation; and the deformation amplitude of the pre-calibrated local fringes being the change in position of the pre-calibrated local fringes in the grating fringe signal and the space carrier signal before and after deformation in a preset reference frame.

[0007] In one possible implementation, the strain unit is used to generate deformation upon receiving a pressure value Pi when the PD data is pre-calibrated; wherein the pressure value Pi is M values ​​divided between zero and the maximum pressure to be measured, and M is a natural number.

[0008] The processing unit is used to drive the grating projection unit to generate grating stripe signals;

[0009] The grating projection unit is used to project the grating stripe signal onto the strain unit that receives the pressure value Pi;

[0010] The camera unit is used to sequentially acquire the space carrier signal obtained by the strain unit modulating the grating stripe signal when it receives the pressure value Pi;

[0011] The processing unit is also used to demodulate the spatial carrier signal corresponding to the pressure value Pi in sequence to obtain the degree of distortion of the spatial carrier signal corresponding to each pressure value Pi relative to the grating stripe signal.

[0012] The storage unit is used to store each pressure value Pi and the degree of distortion of the spatial carrier signal corresponding to the pressure value Pi relative to the grating stripe signal.

[0013] In one possible implementation, the number of camera units is greater than or equal to 2;

[0014] During pressure measurement, the processing unit is further configured to demodulate the spatial carrier signals acquired by the multiple camera units to obtain the degree of distortion of the acquired spatial carrier signals relative to the grating stripe signals corresponding to the multiple camera units, and to perform weighted processing on the degree of distortion corresponding to the multiple camera units to obtain the corrected degree of distortion; the processing unit is further configured to obtain the pressure data received by the strain unit based on the pre-calibrated PD data and the corrected degree of distortion.

[0015] In one possible implementation, the number of camera units is greater than or equal to 2;

[0016] When pre-calibrating PD data, the processing unit is also used to demodulate the spatial carrier signal corresponding to each pressure value Pi obtained by the plurality of camera units to obtain the degree of distortion of the spatial carrier signal corresponding to the plurality of camera units relative to the grating stripe signal. The storage unit is used to store each pressure value Pi and the degree of distortion of the spatial carrier signal corresponding to the pressure value Pi collected by the plurality of camera units relative to the grating stripe signal.

[0017] During pressure measurement, the processing unit is further configured to demodulate the spatial carrier signals acquired by the multiple camera units to obtain the degree of distortion of the spatial carrier signals acquired by the multiple camera units relative to the grating stripe signal; and to obtain pressure data corresponding to the multiple camera units respectively based on the pre-calibrated PD data; and to perform weighted processing on the pressure data corresponding to the multiple camera units to obtain the corrected pressure data received by the strain unit.

[0018] In one possible implementation, the strain unit is a tubular structure with a bottom, the inner diameter of the bottom of the tubular structure being W, and the thickness of the bottom of the tubular structure being H;

[0019] The thickness H is determined based on the maximum pressure to be measured, the elastic modulus of the material of the strain unit, and the Poisson's ratio of the material; wherein, the thickness H is negatively correlated with the elastic modulus of the material of the strain unit and the Poisson's ratio of the material; and the thickness H is positively correlated with the width W of the strain unit and the maximum pressure to be measured.

[0020] In one possible implementation, the pressure measuring device further includes a thermal insulation unit for separating the strain unit from other units in the pressure measuring device;

[0021] The strain unit is made of a high-temperature resistant elastic material.

[0022] In one possible implementation, the pressure measuring device further includes an output unit for outputting the pressure data obtained by the processing unit to a host computer.

[0023] Secondly, this application also provides a pressure measurement method based on any of the measuring devices described in the first aspect above, comprising the following steps:

[0024] The pressure measurement method includes:

[0025] The processing unit drives the grating projection unit to generate grating stripe signals;

[0026] The projection unit transmits the grating stripe signal to the strain unit;

[0027] The strain unit modulates the grating stripe signal based on the deformation generated when it receives pressure, thereby forming the space carrier signal;

[0028] The camera unit sends the acquired space carrier signal to the processing unit;

[0029] The processing unit demodulates the acquired space carrier signal to obtain the degree of distortion of the acquired space carrier signal relative to the grating stripe signal;

[0030] The processing unit calculates the pressure P corresponding to the degree of twisting based on the degree of twisting and the PD data.

[0031] In one possible implementation, the pressure measurement method further includes configuring the pressure measuring device, which is designed with strain elements for the ambient temperature and maximum pressure value of the working environment where pressure needs to be detected.

[0032] The pressure measurement method also includes calibrating the PD data, wherein the PD data is the corresponding data of a pre-recorded PD;

[0033] The pressure measurement method also includes applying an external force to cause deformation of the strain unit.

[0034] In one feasible manner, the fitting algorithm includes at least one of the following: linear fitting, least squares fitting, and multi-order curve fitting.

[0035] Advantages of this application:

[0036] (1) This application uses high-temperature resistant elastic material to configure the strain unit, which has a simple structure and is easy to prepare; it does not require a substrate inside, nor does it have gas or liquid that transmits pressure, thus avoiding the problem that the substrate of most sensors undergoes irreversible plastic deformation when it withstands high temperature; it also avoids the problem that gas or liquid that transmits pressure expands at high temperature, causing a sharp deterioration in performance.

[0037] (2) The pressure measurement method of this application calculates the current pressure by comparing the measured pressure-maximum phase difference with the predetermined pressure-maximum phase difference calibrated beforehand. Unlike conventional raster projection technology, this method does not require calculating the correct height information from the phase, i.e., it does not require finding the correspondence between phase and height information, and therefore does not require calibration of system geometric parameters or the internal parameters of the CCD camera and projection equipment. This method is simple to calculate and easy to operate, greatly reducing system costs.

[0038] (3) In existing technologies, above a certain temperature point, the deformation of the substrate or base material transitions from elastic deformation to plastic deformation, causing a sharp deterioration in sensor performance or loss of function. For example, silicon-based pressure sensors use a PN junction as the sensing junction to detect pressure changes. However, due to the temperature resistance limitations of the PN junction, intrinsic diffusion occurs in silicon when the operating temperature exceeds 125°C, resulting in a severe deterioration in device performance. Above 600°C, plastic deformation and current leakage occur, potentially causing sensor malfunction. These factors make traditional pressure sensors completely unable to meet the requirements for pressure measurement in high-temperature environments in the aforementioned application areas.

[0039] To address the aforementioned issues, the pressure measurement method of this application obtains the measured pressure value by non-contactly measuring the three-dimensional profile deformation of the strain unit using a grating. Only the high-temperature resistant strain unit comes into contact with the high temperature, while the rest of the components do not, making it easy to measure pressure in high-temperature environments above 600°C. Attached Figure Description

[0040] To more clearly illustrate the implementation schemes of this application, the accompanying drawings used in the implementation schemes will be briefly introduced below. It should be understood that the accompanying drawings only show some implementation schemes of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from the accompanying drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of a pressure measuring device in an embodiment of this application;

[0042] Figure 2 This is a schematic diagram of the process for acquiring pre-calibrated PD data in an embodiment of this application;

[0043] Figure 3 This is a schematic diagram of the structure of a pressure measuring device in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of the structure of a pressure measuring device in an embodiment of this application;

[0045] Figure 5 This is a schematic diagram of the structure of a pressure measuring device in an embodiment of this application;

[0046] Figure 6 This is a schematic diagram of the strain unit structure in an embodiment of this application;

[0047] Figure 7 This is a schematic diagram of a pressure measurement method in an embodiment of this application;

[0048] Figure 8 This is a schematic diagram of the deformation amplitude and phase difference of the grating stripe signal in an embodiment of this application. Detailed Implementation

[0049] To clearly illustrate the technical features of this solution, the following detailed implementation methods, in conjunction with the appendix, are provided. Figure 1-8 This application will be described in detail.

[0050] This application provides a pressure measuring device that can meet the requirements for pressure measurement in high-temperature environments and realize pressure measurement in high-temperature environments.

[0051] Example 1:

[0052] like Figure 1 As shown, this application provides a pressure measuring device, comprising: a strain unit for generating deformation when receiving pressure; a grating projection unit for transmitting grating stripe signals to the strain unit; a camera unit for acquiring a space carrier signal, wherein the space carrier signal is formed by the strain unit modulating the grating stripe signal according to the deformation, and the degree of distortion of the modulated space carrier signal relative to the grating stripe signal corresponding to the deformation generated by the strain unit when receiving different pressures is different; a storage unit for storing pre-calibrated PD data, wherein the PD data includes a data queue corresponding to the pressure and the degree of distortion of the space carrier signal relative to the grating stripe signal; and a processing unit for demodulating the acquired space carrier signal to obtain the degree of distortion of the space carrier signal relative to the grating stripe signal, and then obtaining the pressure data received by the strain unit according to the pre-calibrated PD data.

[0053] As an example of implementation, the degree of distortion of the space carrier signal relative to the grating fringe signal includes at least one of the following: the phase difference of pre-calibrated local fringes in the grating fringe signal and the space carrier signal before and after deformation; and the deformation amplitude of pre-calibrated local fringes in the grating fringe signal and the space carrier signal before and after deformation.

[0054] As an example of implementation, the grating fringe signal is an equally spaced grid pattern; the phase difference of the pre-calibrated local fringes is the angle between the pre-calibrated local fringes in the grating fringe signal and the space carrier signal before and after deformation; the deformation amplitude of the pre-calibrated local fringes is the change in position of the pre-calibrated local fringes in the grating fringe signal and the space carrier signal before and after deformation in a preset reference frame.

[0055] As an example of implementation, the strain unit is used to generate deformation upon receiving a pressure value Pi when the PD data is pre-calibrated; wherein the pressure value Pi is M values ​​divided between zero and the maximum pressure to be measured, and M is a natural number.

[0056] The processing unit is used to drive the grating projection unit to generate grating stripe signals;

[0057] The grating projection unit is used to project the grating stripe signal onto the strain unit that receives the pressure value Pi;

[0058] The camera unit is used to sequentially acquire the space carrier signal obtained by the strain unit modulating the grating stripe signal when it receives the pressure value Pi;

[0059] The processing unit is also used to demodulate the spatial carrier signal corresponding to the pressure value Pi in sequence to obtain the degree of distortion of the spatial carrier signal corresponding to each pressure value Pi relative to the grating stripe signal.

[0060] The storage unit is used to store each pressure value Pi and the degree of distortion of the spatial carrier signal corresponding to the pressure value Pi relative to the grating stripe signal.

[0061] As an example of implementation, the number of camera units is greater than or equal to 2;

[0062] During pressure measurement, the processing unit is further configured to demodulate the spatial carrier signals acquired by the multiple camera units to obtain the degree of distortion of the acquired spatial carrier signals relative to the grating stripe signals corresponding to the multiple camera units, and to perform weighted processing on the degree of distortion corresponding to the multiple camera units to obtain the corrected degree of distortion; the processing unit is further configured to obtain the pressure data received by the strain unit based on the pre-calibrated PD data and the corrected degree of distortion.

[0063] As an example of implementation, the number of camera units is greater than or equal to 2;

[0064] When pre-calibrating PD data, the processing unit is also used to demodulate the spatial carrier signal corresponding to each pressure value Pi obtained by the plurality of camera units to obtain the degree of distortion of the spatial carrier signal corresponding to the plurality of camera units relative to the grating stripe signal. The storage unit is used to store each pressure value Pi and the degree of distortion of the spatial carrier signal corresponding to the pressure value Pi collected by the plurality of camera units relative to the grating stripe signal.

[0065] During pressure measurement, the processing unit is further configured to demodulate the spatial carrier signals acquired by the multiple camera units to obtain the degree of distortion of the spatial carrier signals acquired by the multiple camera units relative to the grating stripe signal; and to obtain pressure data corresponding to the multiple camera units respectively based on the pre-calibrated PD data; and to perform weighted processing on the pressure data corresponding to the multiple camera units to obtain the corrected pressure data received by the strain unit.

[0066] As an example of implementation, the strain unit is a tubular structure with a bottom, the inner diameter width of the bottom of the tubular structure being W, and the thickness of the bottom of the tubular structure being H;

[0067] The thickness H is determined based on the maximum pressure to be measured, the elastic modulus of the material of the strain unit, and the Poisson's ratio of the material; wherein, the thickness H is negatively correlated with the elastic modulus of the material of the strain unit and the Poisson's ratio of the material; and the thickness H is positively correlated with the width W of the strain unit and the maximum pressure to be measured.

[0068] As an example of implementation, the pressure measuring device further includes: a thermal insulation unit for separating the strain unit from other units in the pressure measuring device;

[0069] The strain unit is made of a high-temperature resistant elastic material.

[0070] As an example of implementation, the pressure measuring device further includes an output unit for outputting the pressure data obtained by the processing unit to a host computer.

[0071] Example 2:

[0072] This application also provides a pressure measurement method based on any of the pressure measuring devices in Embodiment 1, including the following steps:

[0073] The pressure measurement method includes:

[0074] The processing unit drives the grating projection unit to generate grating stripe signals;

[0075] The projection unit transmits the grating stripe signal to the strain unit;

[0076] The strain unit modulates the grating stripe signal based on the deformation generated when it receives pressure, thereby forming the space carrier signal;

[0077] The camera unit sends the acquired space carrier signal to the processing unit;

[0078] The processing unit demodulates the acquired space carrier signal to obtain the degree of distortion of the acquired space carrier signal relative to the grating stripe signal;

[0079] The processing unit calculates the pressure P corresponding to the degree of twisting based on the degree of twisting and the PD data.

[0080] As an example of an implementable method, the pressure measurement method also includes configuring the pressure measuring device, which is designed with strain elements for the ambient temperature and maximum pressure value of the working environment where pressure needs to be detected.

[0081] The pressure measurement method also includes calibrating the PD data, wherein the PD data is the corresponding data of a pre-recorded PD;

[0082] The pressure measurement method also includes applying an external force to cause deformation of the strain unit.

[0083] Example 3:

[0084] like Figure 1 As shown, this application embodiment provides a pressure measuring device, including:

[0085] Strain elements are used to deform when subjected to pressure; strain elements are made of materials that can withstand temperatures above 600°C and still maintain elastic deformation, specifically ceramics or heat-resistant steel.

[0086] The grating projection unit is used to transmit grating fringe signals to the strain unit; the grating fringe can be straight grid fringe or sinusoidal fringe.

[0087] The camera unit is used to acquire space carrier signals, which are phase-modulated grating fringe signals formed by the deformation height modulation of the grating fringe projection onto the strain unit. When the grating fringes are projected onto the stressed and deformed surface of the strain unit, the projection of the grating fringes will undergo different degrees of deformation. The degree of phase change of the grating fringe projection varies depending on the height of the deformation of the stressed surface of the strain unit, and the phase change carries the three-dimensional morphological information of the deformed surface of the strain unit.

[0088] The storage unit is used to store pre-calibrated PD data. The PD data includes a pre-calibrated data queue corresponding to the pressure and phase difference. The phase difference is the difference in angle change between the space carrier signal and the grating stripe signal when the strain unit has no deformation.

[0089] The processing unit is used to demodulate the space carrier signal and then fit the pre-calibrated PD data to obtain pressure data.

[0090] Among them, the grating stripe signal is the pattern formed by light rays passing through the grating falling on the strain unit. The deformation of the strain unit can be determined by the change of the grating stripe signal. For example, an equally divided grid pattern of lines can be designed to facilitate comparison of the stress on the strain unit.

[0091] When a strain element is subjected to force, it undergoes three-dimensional deformation, resulting in localized distortion of the pattern modulated by the grating fringe signal. By analyzing and comparing the phase-modulated grating fringe signal with the undeformed grating fringe signal, it can be determined that the local fringes have undergone changes in position and angle relative to a certain coordinate system. The change in position represents the deformation amplitude, and the difference in angle represents the phase difference. For example, the coordinate system can be established at the center of the region with the greatest deformation in the central area of ​​the pattern.

[0092] like Figure 8 As shown, the dashed line represents the grating stripe signal without deformation, and the solid line represents the grating stripe signal after phase modulation. When it is necessary to determine the pressure on the strain unit, the pressure corresponding to the phase difference generated by the deformation of the target line segment with the smallest change amplitude is found in the PD data through the preset selected target line segment, such as the line segment with the smallest change amplitude. This pressure is the pressure on the strain unit.

[0093] In one embodiment, demodulating the space carrier signal specifically includes subtracting the phase of the space carrier signal from the phase of the grating fringe signal when the strain element is not deformed to obtain a phase difference, and then fitting the pressure data to pre-calibrated PD data based on the phase difference. The fitting method can be linear fitting, least squares fitting, or multi-order curve fitting.

[0094] In one embodiment, a fixed coordinate system is pre-set as a reference. The PD data also includes a pre-calibrated data queue corresponding to pressure and deformation amplitude. The deformation amplitude is the change in the position of the space carrier signal and the grating stripe signal when the strain unit has no deformation. Demodulating the space carrier signal also includes obtaining the deformation amplitude by measuring the degree of change in the position of the space carrier signal and the grating stripe signal when the strain unit has no deformation with reference to the fixed coordinate system. Then, pressure data is obtained by fitting the pre-calibrated PD data according to the deformation amplitude.

[0095] For example, demodulating a space carrier signal can yield only the phase difference, which can then be used to fit pressure data to pre-calibrated PD data. Alternatively, it can yield only the deformation amplitude, which can then be used to fit pressure data to pre-calibrated PD data. Similarly, both phase difference and deformation amplitude can be used simultaneously to fit pressure data to pre-calibrated PD data, yielding the closest possible pressure data and improving the accuracy of the pressure sensor.

[0096] like Figure 2 As shown, in one embodiment, the steps of the method for acquiring pre-calibrated PD data are as follows:

[0097] S101: Configure a PD data calibration device, which includes a strain unit, a grating projection unit, a first camera unit, a second camera unit, a data processing unit, and a data storage unit;

[0098] S102: Divide the pressure range from zero pressure to the maximum pressure to be measured into M pressure values, each pressure value is denoted as Pi, and M is a natural number; divide the pressure range from zero pressure to the maximum pressure to be measured into N pressure values. The pressure values ​​can be evenly distributed, or the pressure values ​​can be non-evenly distributed according to the linearity of the pressure and maximum height difference of the strained material; less pressure value is allocated to the part with good linearity, and more pressure value is allocated to the part with poor linearity.

[0099] S103: Apply pressure Pi to the strain element; applying pressure Pi means applying pressure Pi to the strain element through a high-precision pressurization device;

[0100] S104: Store the pressure value Pi into the storage unit;

[0101] S105: The processing unit drives the grating projection unit to generate grating fringe signals, and the grating projection unit projects the grating fringe signals onto the stress-deformation surface of the strain unit.

[0102] S106: The grating stripe signal is modulated by the deformation height of the strain unit to form a space carrier signal. The first camera unit and the second camera unit simultaneously acquire the space carrier signal.

[0103] S107: The first camera unit sends the acquired first spatial carrier signal to the processing unit, and the second camera unit sends the acquired second spatial carrier signal to the processing unit;

[0104] S108: The processing unit demodulates the first spatial carrier signal to obtain the maximum phase difference Dli corresponding to the maximum deformation height of the strain unit; the processing unit demodulates the second spatial carrier signal to obtain the maximum phase difference D2i corresponding to the maximum deformation height of the strain unit.

[0105] S109: The processing unit performs weighted processing on D1i and D2i to form Di; the weighted processing can be performed by weighted averaging of D1i and D2i according to preset weighting factors to obtain Di. The preset weighting factors can be default weighting factors, or different weighting factors can be manually given according to the different resolutions or precisions of the camera units, or weighting factors can be given according to the distance of the camera units from the center of the strain unit, with closer ones having larger weighting factors and farther ones having smaller weighting factors;

[0106] S110: Repeat S103-S109 to store all Pi and their corresponding maximum phase difference Di into the storage unit to obtain the pre-calibrated PD data.

[0107] like Figure 3 As shown, in one embodiment, there are two camera units, but in actual configurations there can be more, which can further improve the accuracy of the measurement data.

[0108] like Figure 4 As shown, in one embodiment, the measuring device further includes a heat insulation unit that isolates the strain unit from other units. Isolating the high temperature of the strain unit from other units allows all components to be housed within a single structure, forming a compact system.

[0109] like Figure 5 As shown, in one embodiment, the measuring device further includes an output unit for outputting pressure data to a host computer. In a specific implementation, the output unit can also be a display, which can directly display the pressure P on the screen.

[0110] like Figure 6 As shown, in one embodiment, the strain unit can be a tubular structure with a bottom, the inner diameter width of the bottom being W, the thickness of the bottom being H, the resolution of the grating projection unit being F, the pressure measurement accuracy being A, and the maximum deformation height generated by the strain unit under maximum pressure being δ, then the following formula applies:

[0111] δ<F / A

[0112] To ensure that the strain element deforms into an elastic form under maximum pressure, the following formula applies:

[0113] W > δ / 0.25%

[0114] The thickness H of the bottom of the strain element is determined based on the maximum pressure [Pr] to be measured and the inner diameter W of the strain element bottom, using the following formula:

[0115] [Pr]=8*ε*H2*E / (6*(1-μ2)*(W / 2)2)

[0116] Where e represents the allowable strain coefficient of the strain element material, which is generally taken as a constant of 0.25%; E is the elastic modulus of the strain element material; and μ is the Poisson's ratio of the strain element material.

[0117] This allows us to configure the thickness H at the bottom of the strain element.

[0118] In practice, the bottom is the surface that bears the force, and the direction of the applied pressure is... Figure 6 The middle part is from top to bottom.

[0119] In one embodiment, the strain element is made of a high-temperature resistant elastic material. As an example, the high-temperature resistant elastic material can be ceramic or heat-resistant steel.

[0120] Example 4:

[0121] like Figure 7 As shown, this application embodiment also provides a pressure measurement method based on any of the measuring devices described in Embodiment 2, comprising the following steps:

[0122] S201: Configure pressure measuring device;

[0123] S202: Calibrate PD data;

[0124] S203: Applying external force causes deformation in the strain element;

[0125] S204: The processing unit drives the grating projection unit to generate grating fringe signals, and the projection unit transmits the grating fringe signals to the stress deformation surface of the strain unit.

[0126] S205: The grating stripe signal is modulated by the deformation height of the strain unit to form a space carrier signal, which is then acquired by the camera unit;

[0127] S206: The camera unit sends the acquired space carrier signal to the processing unit;

[0128] S207: The processing unit demodulates the space carrier signal to obtain the maximum phase difference D corresponding to the maximum deformation height of the strain element;

[0129] S208: The processing unit calculates the pressure P corresponding to the maximum phase difference D using a fitting algorithm based on the maximum phase difference D and PD data.

[0130] In one embodiment, the fitting algorithm includes at least one of the following: linear fitting, least squares fitting, and multi-order curve fitting.

[0131] Example 5:

[0132] This application also provides a pressure measurement method.

[0133] As an implementable example, configuring strain elements includes the following steps:

[0134] S301: The strain element is made of a material that can withstand temperatures above 600°C and still maintain elastic deformation; specifically, ceramic materials or heat-resistant steel can be selected to make the strain element.

[0135] S302: Determine the structure of the strain element and select a cavity structure;

[0136] S303: Determine the width W and thickness H of the cavity structure.

[0137] As an implementable example, pre-calibrating and storing the first PD data and the second PD data includes the following steps:

[0138] S311: The pressure range from zero pressure to the maximum pressure to be measured is divided into N pressure values, each of which is denoted as Pi;

[0139] S312: Apply pressure Pi to the strain unit; input the pressure value Pi to the processing unit through the input unit;

[0140] S313: The processing unit drives the grating projection unit to generate grating stripes and project them onto the surface of the strain unit 1;

[0141] S314: The grating stripes are highly modulated by the strain element, forming a phase-modulated spatial carrier signal;

[0142] S315: The first and second camera units simultaneously acquire: space carrier signals;

[0143] S316: The first camera unit transmits the acquired first spatial carrier data to the processing unit, and the second camera unit transmits the acquired second spatial carrier data to the processing unit;

[0144] S317: The processing unit demodulates the first spatial carrier data to obtain the maximum phase difference D1i corresponding to the maximum height difference of the strain unit; the processing unit demodulates the second spatial carrier data to obtain the maximum phase difference D2i corresponding to the maximum height difference of the strain unit.

[0145] S318: Repeat steps S305-S311 to form a first PD queue with all pressure Pi and the corresponding maximum phase difference D1i, and form a second PD array with all pressure Pi and the corresponding maximum phase difference D2i.

[0146] S319: The processing unit stores the first PD queue and the second PD queue into the storage unit.

[0147] As an example of what can be done, the specific steps are as follows:

[0148] S321: Applying external force causes deformation in the strain element;

[0149] S322: The processing unit drives the grating projection unit to generate grating fringes and projects them onto the surface of the strain unit;

[0150] S323: The grating fringes are highly modulated by the strain element, forming a phase-modulated spatial carrier signal;

[0151] S324: The first and second camera units simultaneously acquire space carrier signals;

[0152] S325: The first camera unit transmits the acquired first spatial carrier data to the processing unit, and the second camera unit transmits the acquired second spatial carrier data to the processing unit;

[0153] S326: The processing unit demodulates the first spatial carrier data to obtain the maximum phase difference D1 corresponding to the maximum height difference of the strain unit; the processing unit demodulates the second spatial carrier data to obtain the maximum phase difference D2 corresponding to the maximum height difference of the strain unit.

[0154] S327: The processing unit reads the pre-calibrated first PD queue and second PD queue from the storage unit;

[0155] S328: Based on the first PD data read, the processing unit uses a fitting method to calculate the pressure P1 corresponding to the maximum phase difference D1. Based on the second PD data read, the processing unit uses a fitting method to calculate the pressure P2 corresponding to the maximum phase difference D2.

[0156] S329: According to the preset weighting factor, the processing unit 61 performs weighted average processing on P1 and P2 to obtain the pressure P borne by the strain unit 1, and the processing unit outputs the pressure P to the output unit.

[0157] Specifically, S322 involves the processing unit transmitting the signal of the grating stripes to be projected to the grating projection unit, which then generates grating stripes and projects them onto the surface of the strain unit. For example, the grating stripes can be straight grid stripes or sinusoidal stripes.

[0158] Specifically, S323 refers to the deformation of the grating fringes when projected onto the surface of the strain element. The phase change of the grating fringes projection varies with the height of the strain element 1, and this phase change carries information about the three-dimensional morphology of the object's surface.

[0159] Specifically, S324 involves the processing unit simultaneously sending acquisition commands to the first camera unit and the second camera unit, and the first camera unit and the second camera unit simultaneously acquiring space carrier signals.

[0160] In S326, demodulation refers to the processing unit subtracting the first spatial carrier signal from the grating stripe signal to be projected to obtain the phase difference, and the processing unit subtracting the second spatial carrier signal from the grating stripe signal to be projected to obtain the phase difference.

[0161] Among them, the fitting method in S328 can be a straight line fitting, least squares fitting, or multi-order curve fitting, etc.

[0162] The preset weighting factor in S329 is either a default weighting factor, or a weighting factor that is manually assigned based on the resolution or accuracy of the camera unit, or a weighting factor that is assigned from large to small based on the distance of the camera unit from the center of the strain unit.

[0163] Advantages of this application:

[0164] (1) This application uses high-temperature resistant elastic material to configure the strain unit, which has a simple structure and is easy to prepare; it does not require a substrate inside, nor does it have gas or liquid that transmits pressure, thus avoiding the problem that the substrate of most sensors undergoes irreversible plastic deformation when it withstands high temperature; it also avoids the problem that gas or liquid that transmits pressure expands at high temperature, causing a sharp deterioration in performance.

[0165] (2) The pressure measurement method of this application calculates the current pressure by comparing the measured pressure-maximum phase difference with the predetermined pressure-maximum phase difference calibrated beforehand. Unlike conventional raster projection technology, this method does not require calculating the correct height information from the phase, i.e., it does not require finding the correspondence between phase and height information, and therefore does not require calibration of system geometric parameters or the internal parameters of the CCD camera and projection equipment. This method is simple to calculate and easy to operate, greatly reducing system costs.

[0166] (3) In existing technologies, above a certain temperature point, the deformation of the substrate or base material transitions from elastic deformation to plastic deformation, causing a sharp deterioration in sensor performance or loss of function. For example, silicon-based pressure sensors use a PN junction as the sensing junction to detect pressure changes. However, due to the temperature resistance limitations of the PN junction, intrinsic diffusion occurs in silicon when the operating temperature exceeds 125°C, resulting in a severe deterioration in device performance. Above 600°C, plastic deformation and current leakage occur, potentially causing sensor malfunction. These factors make traditional pressure sensors completely unable to meet the requirements for pressure measurement in high-temperature environments in the aforementioned application areas.

[0167] To address the aforementioned problems, the pressure measurement method of this application obtains the measured pressure value by non-contactly measuring the three-dimensional profile deformation of the strain unit using a grating. Only the high-temperature resistant strain unit comes into contact with the high temperature, while the rest remains untouched, easily enabling pressure measurement in environments exceeding 600°C. The above-described embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A pressure measuring device, characterized in that, include: Strain element, used to generate deformation when subjected to pressure; A grating projection unit is used to transmit grating fringe signals to the strain unit; The camera unit is used to acquire space carrier signals. The space carrier signals are formed by the strain unit modulating the grating stripe signals according to the deformation. The degree of distortion of the modulated space carrier signals relative to the grating stripe signals is different when the strain unit receives different amounts of pressure. A storage unit for storing pre-calibrated PD data, the PD data including a data queue corresponding to the degree of distortion of the pressure and the space carrier signal relative to the grating stripe signal; The processing unit is used to demodulate the acquired space carrier signal to obtain the degree of distortion of the space carrier signal relative to the grating stripe signal, and then obtain the pressure data received by the strain unit based on the pre-calibrated PD data.

2. The pressure measuring device according to claim 1, characterized in that, The degree of distortion of the spatial carrier signal relative to the grating stripe signal includes at least one of the following: The phase difference of pre-calibrated local fringes in the grating fringe signal and space carrier signal before and after deformation; The change in position of pre-calibrated local fringes in the grating fringe signal and space carrier signal before and after deformation.

3. A pressure measuring device according to claim 2, characterized in that, The grating stripe signal is an equally spaced grid pattern; The phase difference of the pre-calibrated local stripes is the angle between the pre-calibrated local stripes in the grating stripe signal and the space carrier signal before and after deformation.

4. A pressure measuring device according to claim 2, characterized in that, The strain unit is used to generate deformation when receiving pressure value Pi during the pre-calibration of PD data; wherein, the pressure value Pi is M values ​​divided between zero and the maximum pressure to be measured, and M is a natural number; The processing unit is used to drive the grating projection unit to generate grating stripe signals; The grating projection unit is used to project the grating stripe signal onto the strain unit that receives the pressure value Pi; The camera unit is used to sequentially acquire the space carrier signal obtained by the strain unit modulating the grating stripe signal when it receives the pressure value Pi; The processing unit is also used to demodulate the spatial carrier signal corresponding to the pressure value Pi in sequence to obtain the degree of distortion of the spatial carrier signal corresponding to each pressure value Pi relative to the grating stripe signal. The storage unit is used to store each pressure value Pi and the degree of distortion of the spatial carrier signal corresponding to the pressure value Pi relative to the grating stripe signal.

5. A pressure measuring device according to any one of claims 4, characterized in that, The number of camera units is greater than or equal to 2; During pressure measurement, the processing unit is further configured to demodulate the spatial carrier signals acquired by the multiple camera units to obtain the degree of distortion of the acquired spatial carrier signals relative to the grating stripe signals corresponding to the multiple camera units, and to perform weighted processing on the degree of distortion corresponding to the multiple camera units to obtain the corrected degree of distortion; the processing unit is further configured to obtain the pressure data received by the strain unit based on the pre-calibrated PD data and the corrected degree of distortion.

6. A pressure measuring device according to claim 4, characterized in that, The number of camera units is greater than or equal to 2; When pre-calibrating PD data, the processing unit is also used to demodulate the spatial carrier signal corresponding to each pressure value Pi obtained by the plurality of camera units to obtain the degree of distortion of the spatial carrier signal corresponding to the plurality of camera units relative to the grating stripe signal. The storage unit is used to store each pressure value Pi and the degree of distortion of the spatial carrier signal corresponding to the pressure value Pi collected by the plurality of camera units relative to the grating stripe signal. During pressure measurement, the processing unit is further configured to demodulate the spatial carrier signals acquired by the multiple camera units to obtain the degree of distortion of the spatial carrier signals acquired by the multiple camera units relative to the grating stripe signal; and to obtain pressure data corresponding to the multiple camera units respectively based on the pre-calibrated PD data; and to perform weighted processing on the pressure data corresponding to the multiple camera units to obtain the corrected pressure data received by the strain unit.

7. A pressure measuring device according to claim 4, characterized in that, The strain unit is a tubular structure with a bottom, the inner diameter of the bottom of the tubular structure is W, and the thickness of the bottom of the tubular structure is H; The thickness H is determined based on the maximum pressure to be measured, the elastic modulus of the material of the strain unit, and the Poisson's ratio of the material; wherein, the thickness H is negatively correlated with the elastic modulus of the material of the strain unit and the Poisson's ratio of the material; and the thickness H is positively correlated with the width W of the strain unit and the maximum pressure to be measured.

8. A pressure measuring device according to claim 7, characterized in that, The pressure measuring device further includes a heat insulation unit, which is used to separate the strain unit from other units in the pressure measuring device; The strain unit is made of a high-temperature resistant elastic material.

9. A pressure measuring device according to any one of claims 1-8, characterized in that, The pressure measuring device further includes an output unit, which is used to output the pressure data obtained by the processing unit to a host computer.

10. A pressure measurement method based on a pressure measuring device according to any one of claims 1-9, characterized in that, The pressure measurement method includes: The processing unit drives the grating projection unit to generate grating stripe signals; The projection unit transmits the grating stripe signal to the strain unit; The strain unit modulates the grating stripe signal based on the deformation generated when it receives pressure, thereby forming the space carrier signal; The camera unit sends the acquired space carrier signal to the processing unit; The processing unit demodulates the acquired space carrier signal to obtain the degree of distortion of the acquired space carrier signal relative to the grating stripe signal; The processing unit calculates the pressure P corresponding to the degree of twisting based on the degree of twisting and the PD data.

Images