Flexible piezoresistive sensor compensation and respiratory measurement devices, systems, and methods

Abstract

In a flexible piezoresistive sensor compensation and respiration measurement device, system and method, a sensor resistance compensation voltage dividing module and a flexible piezoresistive pressure sensor form a resistance voltage dividing network for a signal filtering and amplifying module; a main control module acquires a voltage output value VA, queries a sensor characteristic curve table to acquire a piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor, and calculates a voltage dividing resistance ratio of the flexible piezoresistive pressure sensor in the signal filtering and amplifying module under the piezoresistive sensitivity value SA; according to the voltage dividing resistance ratio, a target voltage dividing resistance value is calculated; according to the target resistance value, the main control module sends an instruction to the sensor resistance compensation voltage dividing module to set a compensation resistance value output by the compensation resistance module. The non-linear characteristics of the sensor output characteristics under different pressures can be compensated, the output characteristics of the flexible piezoresistive pressure sensor tend to be linear, and subsequent signal acquisition and calculation are facilitated.

Description

Technical Field

[0001] This application relates to the technical field of human signal acquisition devices and methods, and in particular to a flexible piezoresistive sensor compensation device, system and method, as well as a respiratory measurement device, system and method based on flexible piezoresistive sensor compensation. Background Technology

[0002] There are various methods for measuring human respiration in existing technologies. Methods for monitoring respiration during sleep mainly fall into the following categories: Measuring respiratory rhythm and depth based on changes in chest impedance caused by respiration. During respiration, the expansion and contraction of the chest causes changes in chest impedance. External excitation converts the chest impedance signal into a voltage signal, thereby measuring the rhythm and depth of respiration. This method directly uses the chest impedance signal as the measurement object, representing the respiratory signal. This measurement requires electrodes placed at corresponding positions on the chest to acquire the signal, usually using electrocardiogram electrodes. Such measurements not only require at least two cables directly connected to the person, but also external high-frequency excitation and detection circuits. This can cause some pressure and discomfort for the patient, and requires high reliability of the electrode lead connections, making it unsuitable for long-term monitoring or monitoring during sleep.

[0003] Measuring respiratory rhythm and depth based on pressure changes in respiratory airflow caused by respiration typically relies on a resistive bridge pressure sensor. This sensor transmits airway pressure via a nasal cannula or face mask to the sensor's interface, causing it to output a corresponding electrical signal to measure respiratory rhythm and depth. However, this method requires prolonged patient use of the nasal cannula or mask to fix the pressure sensor in the airway, resulting in insufficient comfort and preventing long-term, non-intrusive monitoring. This new method, on the other hand, measures the pressure changes in the respiratory airway caused by respiratory airflow, using the pressure signal as a representation of the respiratory signal.

[0004] Typically, in existing technologies, the rise and fall of the chest cavity caused by human respiration also leads to changes in chest cavity pressure. Such changes appear to be quite dramatic, but they are not easy to obtain accurately because the pressure signal caused by respiration is often easily interfered with. For example, changes in body position or coughing can lead to measurement deviations.

[0005] Breathing detection during sleep, whether using a connecting cable attached to the chest or a breathing mask, offers a poor user experience and is far from comfortable, posing a challenge for continuous monitoring. In sleep-related breathing detection scenarios, to ensure user comfort, sensors are often placed within the mattress or sheet, detecting breathing by measuring changes in chest pressure through contact between the mattress / sheet and the chest. In such detection, piezoelectric sensors are typically used, directly converting pressure signals into electrical signals – a common signal acquisition method. However, piezoelectric sensors can only convert pressure changes and cannot detect static pressure. Therefore, the presence of the object being measured on the sheet or mattress requires an additional sensor, such as a flexible piezoresistive sensor. This necessitates two sensors in the measurement system, increasing detection costs. Conversely, if only a piezoelectric sensor is used, the system must be constantly operational, resulting in energy inefficiency.

[0006] Flexible piezoresistive sensors are typically used as transient pressure sensors, and their application in respiratory measurement is not currently observed. In supine respiratory measurement, flexible piezoresistive sensors are often only used to detect the presence of a person in bed; the corresponding measurement device is activated when a person is detected in bed.

[0007] If a flexible piezoresistive sensor is used to simultaneously detect an object's presence in bed and its respiration, then both states can be detected with a single sensor. The flexible piezoresistive sensor converts the applied pressure signal into resistance information. Flexible piezoresistive pressure sensors are typically based on the pressure-resistance properties of a material, converting the pressure applied to the material into the magnitude of its resistance to achieve pressure measurement. For example... Figure 1 As shown, the structural features of a flexible piezoresistive pressure sensor are evident. Figure 1 Number 10 is a flexible piezoresistive material, which is a continuous flexible strip used to sense pressure and convert pressure into resistance value.

[0008] As a new attempt, the use of flexible piezoresistive sensors for respiratory measurement has also encountered problems. When measuring subjects with different weights, the output characteristics of flexible piezoresistive sensors vary greatly, resulting in lower sensitivity of respiratory measurement for heavier or lighter subjects compared to subjects with intermediate weight.

[0009] Definitions:

[0010] Sensitivity is a technical indicator that represents the degree to which an instrument responds to weak energy. If the instrument's pointer deflects or outputs a large amount of energy while using relatively little energy, its sensitivity is high.

[0011] The piezoresistive sensitivity value SA means the change in resistance per unit area caused by a change in pressure, i.e., dR / dF; dR is the change in resistance, and dF is the pressure per unit area; piezoresistive sensitivity. Summary of the Invention

[0012] This application overcomes the limitations of existing technologies that cannot simultaneously perform in-bed detection and respiratory detection using flexible piezoresistive pressure sensors, and the significant differences in output characteristics of flexible piezoresistive sensors when measuring respiratory measurements for subjects of different weights. It proposes a flexible piezoresistive sensor compensation device, system, and method that can acquire respiratory signals without the user's awareness and provides good consistency in respiratory measurements for subjects of different weights. Furthermore, it provides a respiratory measurement device, system, and method based on flexible piezoresistive sensor compensation. Respiratory measurements can be performed as long as the chest is against the sensor, or when the person is lying down and one side of their chest is in contact with the sensor. This eliminates the need for additional connections such as cables and masks, greatly enhancing the user experience of respiratory measurement and ensuring good consistency in respiratory measurements for subjects of different weights.

[0013] The technical solution to the above-mentioned technical problems is a flexible piezoresistive sensor compensation system for compensating the output characteristics of a flexible piezoresistive pressure sensor. It includes a main control module, a signal filtering and amplification module, and a sensor resistance compensation voltage divider module. The output terminals of the main control module and the signal filtering and amplification module are electrically connected to obtain the voltage signal output by the signal filtering and amplification module. The input terminal of the signal filtering and amplification module is electrically connected to the output terminal of an external flexible piezoresistive pressure sensor to filter and amplify the voltage signal output by the flexible piezoresistive pressure sensor after excitation by a constant voltage source. The main control module obtains the voltage output value VA of the flexible piezoresistive pressure sensor through the signal filtering and amplification module. One end of the sensor resistance compensation voltage divider module is electrically connected to the main control module to obtain resistance setting instructions from the main control module and set its own resistance according to the resistance setting instructions. The sensor resistance compensation voltage divider module as a whole acts as a resistive device connected to the external... The flexible piezoresistive pressure sensor forms a resistive voltage divider network for the signal filtering and amplification module. The sensor resistance compensation voltage divider module is also used for electrical connection to an external constant voltage source, enabling the external flexible piezoresistive pressure sensor, after being excited by the external constant voltage source, to convert the resistance change signal of the flexible piezoresistive pressure sensor into a voltage signal output. The main control module has a pre-built sensor characteristic curve table. Based on the acquired voltage output value VA, the main control module queries the sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor. Based on the piezoresistive sensitivity value SA, the main control module calculates the voltage divider resistance ratio of the flexible piezoresistive pressure sensor in the signal filtering and amplification module at that piezoresistive sensitivity value SA. Based on the voltage divider resistance ratio, the target voltage divider resistance value is obtained. Based on the target resistance value, the main control module sends a command to the sensor resistance compensation voltage divider module to set the compensation resistance value output by the compensation resistance module.

[0014] Before acquiring the voltage output value VA of the external flexible piezoresistive pressure sensor, the main control module sends a command to the sensor resistance compensation voltage divider module to set the voltage divider resistance value of the sensor resistance compensation voltage divider module to be within the upper limit range of its resistance value; the upper limit range is 0.5 to 1.5 times the open-loop resistance of the flexible force resistance sensor.

[0015] Before calculating the voltage divider resistance ratio in the signal filtering and amplification module of the flexible piezoresistive pressure sensor under the piezoresistive sensitivity value SA, the main control module first obtains the voltage divider resistance value of the sensor resistance compensation voltage divider module.

[0016] The main control module is equipped with an AD conversion module, which is used to convert the analog signal input to the main control module from the signal filtering and amplification module into a digital signal.

[0017] A further technical solution to the aforementioned technical problems is a flexible piezoresistive sensor compensation circuit device for compensating flexible piezoresistive pressure sensors. This device includes a signal filtering and amplification module and a sensor resistance compensation voltage divider module. The output of the signal filtering and amplification module is electrically connected to an external main control module, outputting a voltage signal to the main control module. One end of the sensor resistance compensation voltage divider module is electrically connected to the external main control module, used to obtain resistance setting instructions from the external main control module and set its own resistance according to the resistance setting instructions. The sensor resistance compensation voltage divider module is also electrically connected to an external constant voltage source, so that the external flexible piezoresistive pressure sensor, after being excited by the external constant voltage source, converts the resistance change signal of the flexible piezoresistive pressure sensor into a voltage signal output. The sensor resistance compensation voltage divider module as a whole acts as a resistive device, forming a resistance voltage divider network with the external flexible piezoresistive pressure sensor for the signal filtering and amplification module. The input of the signal filtering and amplification module is electrically connected to the output of the external flexible piezoresistive pressure sensor, used to filter and amplify the voltage signal output by the flexible piezoresistive pressure sensor after being excited by the constant voltage source.

[0018] The sensor resistance compensation voltage divider module includes a variable resistor, which sets its own resistance value according to external instructions.

[0019] The sensor resistance compensation voltage divider module includes a voltage divider resistor selection circuit and at least three voltage divider resistors; each path in the voltage divider resistor selection circuit is connected to one voltage divider resistor; the voltage divider resistor selection circuit selects the corresponding voltage divider resistor to enter the circuit network according to external instructions.

[0020] The voltage divider resistor gating circuit includes a multiplexer switch; the multiplexer switch includes multiple input connection terminals, each of which is electrically connected to one end of a voltage divider resistor, and the other end of the voltage divider circuit is used to electrically connect to an external constant voltage excitation source V; the multiplexer switch includes multiple control command receiving terminals, which are used to obtain switch gating commands from the outside; the multiplexer switch includes an output terminal, which is used to electrically connect to an output terminal of an external flexible piezoresistive pressure sensor.

[0021] The flexible piezoresistive sensor compensation circuit device further includes a constant voltage excitation source V, which is electrically connected to a resistor voltage divider network to provide constant voltage excitation to the resistor voltage divider network.

[0022] The signal filtering and amplification module is an AC voltage signal amplification circuit, including amplifier A, resistors R40, R41, R38, R39, capacitor C35, and capacitor C36. The positive input terminal of amplifier A is electrically connected to one end of resistor R41, and the other end of resistor R41 is electrically connected to the amplifier's reference voltage terminal VREF. The positive input terminal of amplifier A is electrically connected to one end of capacitor C36. The other end of capacitor C36 is electrically connected to one end of capacitor C35, and the other end of capacitor C35 is used to connect to one output terminal of a piezoresistive sensor. The other end of capacitor C35 is also electrically connected to one end of resistor R40. The other end of R40 is electrically connected to one end of resistor R39, and the other end of resistor R40 is electrically connected to the output terminal of amplifier A; the other end of resistor R39 is electrically connected to the negative input terminal of amplifier A, the negative input terminal of amplifier A is connected to one end of resistor R38, and the other end of resistor R38 is electrically connected to the reference voltage terminal VREF of amplifier A; the output terminal of amplifier A is used to output a voltage signal characterizing respiration; the values ​​of resistors R40, R41, R38, R39, capacitor C35, and capacitor C36, together with amplifier A, form a high-pass filter with a cutoff frequency F1 ≈ 0.1Hz.

[0023] The signal filtering and amplification module further includes a low-pass filter; the low-pass filter includes a resistor R42 and a capacitor C38; one end of the resistor R42 is electrically connected to the output terminal of amplifier A; the other end of the resistor R42 is electrically connected to one end of the capacitor C38, and the other end of the resistor R42 serves as the output terminal of the signal filtering and amplification module, used to output a voltage signal characterizing breathing; the other end of the capacitor C38 is grounded; the resistor R42 has a value of 2kΩ, the capacitor C38 has a value of 10uF, and the low-pass filter cutoff frequency is...

[0024] The amplifier A is a high-precision general-purpose amplifier of model GS358; the piezoresistive sensor is a flexible integrated composite flexible micro-nano sensor of model YD-SF23-600, which includes a flexible piezoresistive pressure sensor.

[0025] A further technical solution to the above-mentioned technical problems is a flexible piezoresistive sensor compensation method, comprising the following steps: Step B: Obtaining the voltage output value VA of the flexible piezoresistive pressure sensor; Step D: Based on the voltage output value VA obtained in Step B, consulting a pre-fabricated sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor; Step E: Based on the piezoresistive sensitivity value SA obtained in Step D, calculating the voltage division resistance ratio between the flexible piezoresistive pressure sensor and the connected sensor resistance compensation voltage divider module; Step F: Based on the voltage division resistance ratio calculated in Step E, sending a command to the sensor resistance compensation voltage divider module to set the resistance value of the sensor resistance compensation voltage divider module, which participates in the voltage division of the flexible piezoresistive pressure sensor.

[0026] Before step B, step A is also included: sending a command to the sensor resistance compensation voltage divider module to set the resistance value of the sensor resistance compensation voltage divider module to be within the upper limit range of its resistance value; the upper limit range is 0.5 to 1.5 times the open-loop resistance of the flexible force resistance sensor.

[0027] The piezoresistive sensor compensation method further includes the following steps: Step B includes: obtaining the voltage output value VA of the flexible piezoresistive pressure sensor under static pressure A; Step C: determining whether the flexible piezoresistive pressure sensor is under pressure based on the voltage output value VA obtained in Step B; if the voltage output value VA is greater than or equal to the set voltage threshold A, it is determined that pressure is acting on the flexible piezoresistive pressure sensor, and then proceeding to Step D; Step D: based on the voltage output value VA obtained in Step B, consulting the pre-made sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor under static pressure A; before Step C, there is also Step C1, the step of determining the voltage threshold A; before Step D, there is also the step of obtaining the pre-made sensor characteristic curve table; before Step E, there is also the step of obtaining the resistance value of the sensor resistance compensation voltage divider module.

[0028] Another technical solution to the above-mentioned technical problems is a flexible piezoresistive pressure sensor, including the aforementioned flexible piezoresistive sensor compensation circuit device.

[0029] Another technical solution to the above-mentioned technical problems is a respiratory measurement device, including the aforementioned flexible piezoresistive sensor compensation circuit device.

[0030] Another technical solution to the above-mentioned technical problems is a respiratory measurement system, including the aforementioned flexible piezoresistive sensor compensation system.

[0031] Another technical solution to the above-mentioned technical problems is a respiratory measurement method, including the aforementioned piezoresistive sensor compensation method.

[0032] Compared with existing technologies, one of the advantages of this application is that it provides a circuit and device that can simultaneously perform bed detection and respiration detection based on a piezoresistive sensor, which greatly saves the cost of detection hardware and has excellent application potential in a large number of disposable measuring sheets.

[0033] Compared with the prior art, the second beneficial effect of this application is that it provides a method to first obtain the current pressure, then look up the pre-made sensor characteristic curve table based on the current pressure value to obtain the piezoresistive sensitivity value SA under the current pressure, and calculate the voltage divider resistor ratio in the corresponding signal filtering and amplification module based on the piezoresistive sensitivity value SA. This compensates for the nonlinearity of the output of the flexible piezoresistive pressure sensor and the nonlinearity of the sensor output characteristics under different pressures, making the output characteristics of the flexible piezoresistive pressure sensor more linear, which facilitates subsequent signal acquisition and calculation.

[0034] Compared with the prior art, the third beneficial effect of this application is: to send instructions to the signal filtering and amplification module to set the voltage divider resistor value in the external signal filtering and amplification module to be within the upper limit range of its resistance value; the upper limit range is 0.5 to 1.5 times the open-loop resistance of the flexible force resistance sensor; so that the resistance of the voltage divider resistor network matches the open-loop resistance of the flexible force resistance sensor, which can ensure that static pressure can be detected when the power is turned on.

[0035] Compared with the prior art, the fourth beneficial effect of this application is that the setting of the voltage threshold A ensures that the static pressure compensation is activated only when the static pressure exceeds a certain threshold and the deviation of its output characteristic curve from the nominal output characteristic curve is large enough.

[0036] Compared with the prior art, the fifth beneficial effect of this application is: the step of pre-fabricating the sensor characteristic curve table, which pre-fabricates the sensor characteristic curve table and stores the table in the main control module, improves the system efficiency.

[0037] Compared with the prior art, the sixth beneficial effect of this application is that the step of obtaining the resistance value of the voltage divider resistor can perform corresponding compensation resistor calculations based on different voltage divider resistor values, ensuring the accuracy and adaptability of compensation, and having good adaptability to different voltage divider resistor networks.

[0038] Compared with the prior art, the seventh beneficial effect of this application is that the pressure sensor compensation circuit has a simple structure and is easy to implement, and uses a simple controllable resistor network to achieve nonlinear adjustment of complex output characteristic curves.

[0039] Compared with the prior art, the eighth beneficial effect of this application is that the sensor resistance compensation voltage divider module can be compensated using a simple step-by-step selection of resistance value compensation mode or a continuous resistance value compensation mode, making the compensation method richer and more adaptable, and convenient for flexible selection according to conditions.

[0040] Compared with the prior art, the ninth beneficial effect of this application is that the pressure compensation method and system are applicable to pressure detection in respiratory measurement, and the pressure compensation method effectively simulates the nonlinear drift of the sensor output characteristic curve caused by a human lying supine on a flexible piezoresistive pressure sensor.

[0041] Compared with the prior art, the tenth beneficial effect of this application is that the setting of the voltage threshold A ensures the opening threshold of static pressure. The respiratory signal is only output after the static pressure is greater than a certain threshold, that is, after the on-bed detection is completed, thus ensuring the stability of the overall measurement.

[0042] Compared with the prior art, the eleventh beneficial effect of this application is that the setting of constant voltage excitation source V and resistor voltage divider network ensures the working state of the circuit, and the resistor voltage divider network ensures that the current flowing through the sensor is within a suitable range.

[0043] Compared with the prior art, the twelfth beneficial effect of this application is that the setting of the signal filtering and amplification module enables conventional piezoresistive sensors to be used for respiratory signal measurement. The piezoresistive sensor converts the changing pressure into a changing resistance, and the setting of the signal filtering and amplification module converts the changing resistance signal into a voltage signal, which is then output as a respiratory signal.

[0044] Compared with the prior art, the thirteenth beneficial effect of this application is that a high-pass filter is also set in the signal filtering and amplification module to filter out the influence of low-frequency slow-varying noise on the measurement.

[0045] Compared with the prior art, the fourteenth beneficial effect of this application is that a low-pass filter is also provided in the signal filtering and amplification module to filter out the influence of high-frequency noise on the measurement.

[0046] Compared with the prior art, the fifteenth beneficial effect of this application is that the cutoff frequencies of the high-pass filter and low-pass filter in the signal filtering and amplification module are very suitable for the measurement of respiratory signals and can amplify the respiratory signals just right. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of an embodiment of a flexible piezoresistive pressure sensor;

[0048] Figure 2This is a schematic diagram of the pressure resistance output characteristic curve of the YD-SF23-600 flexible piezoresistive pressure sensor;

[0049] Figure 3 It is an output characteristic curve of a flexible piezoresistive pressure sensor under a uniform pressure model and an output characteristic curve under a human body model;

[0050] Figure 4 This is a specific embodiment of a flexible piezoresistive sensor compensation system;

[0051] Figure 5 This is one of the specific embodiments of a flexible piezoresistive sensor compensation circuit device;

[0052] Figure 6 This is a second specific embodiment of the flexible piezoresistive sensor compensation circuit device;

[0053] Figure 7 This is a specific embodiment of the signal filtering and amplification module;

[0054] Figure 8 This is a schematic diagram of the voltage signal output by the signal filtering and amplification module after compensation by the flexible piezoresistive sensor.

[0055] Figure 9 This is a schematic diagram of an embodiment of a flexible piezoresistive sensor compensation method. Detailed Implementation

[0056] The contents of this application will be further described in detail below with reference to various embodiments.

[0057] like Figure 1 The diagram shown is a schematic representation of an embodiment of a flexible piezoresistive pressure sensor. In this embodiment, a flexible integrated composite flexible micro / nano sensor, model YD-SF23-600, is used, including a flexible piezoresistive pressure sensor. Reference numeral 10 represents the flexible piezoresistive sensing region; reference numeral 20 represents the piezoelectric sensing region. In this application's technical solution, the piezoelectric sensing region is not activated; only the flexible piezoresistive sensing region is activated. In practical applications, the technical solution in this application can also be used in devices, systems, and methods for respiratory measurement using other types of flexible piezoresistive pressure sensors.

[0058] like Figure 2 The diagram shows the pressure-resistance output characteristic curve of the YD-SF23-600 flexible piezoresistive pressure sensor. In the diagram, ▽F represents ▽P, the pressure change; ▽R represents the resistance change; the piezoresistive sensitivity value SA = dR / dF, which is ▽R / ▽F; dR is the resistance change, and dF is the pressure per unit area. When using the flexible piezoresistive pressure sensor for respiratory measurement, it is based on the differential characteristic of the output characteristic curve, meaning that pressure changes lead to resistance changes. The characteristic of converting pressure changes caused by respiration into resistance changes.

[0059] Flexible piezoresistive pressure sensors typically utilize the pressure-resistance properties of materials, converting pressure applied to the material into a change in its resistance to achieve pressure measurement. For example... Figure 2 The output characteristic curve of the nominal flexible piezoresistive pressure sensor shown was obtained under standard pressure test conditions, i.e., under uniform pressure across the entire pressure-sensing surface of the flexible piezoresistive pressure sensor. Therefore, the overall linearity is good. That is, there is a basically linear correlation between the input pressure and the output resistance, at least within a certain pressure range. However, since the flexible piezoresistive pressure sensor is composed of multiple pressure-sensing strips assembled together, and when used for measuring respiration in a supine position, it is impossible to guarantee uniform pressure applied to the entire sensing area of ​​the sensor as under standard pressure test conditions. Therefore, the output characteristics of the flexible piezoresistive pressure sensor are not as... Figure 2 The standard curve is so standard.

[0060] However, in practical applications, it cannot be guaranteed that the pressure on the pressure-sensing surface of a flexible piezoresistive pressure sensor is uniformly distributed, therefore its output characteristic curve will vary slightly. For example... Figure 3 The figure shows the output characteristic curves of a flexible piezoresistive pressure sensor under a uniform pressure model and under a human body model. Figure 3 The curve marked with an asterisk (*) in the lower middle section is the output characteristic curve of the pressure sensing surface of the flexible piezoresistive pressure sensor under the pressure model of a supine human body. It has a significant difference compared to the output characteristic curve of the nominal flexible piezoresistive pressure sensor. Figure 3 As can be seen, under the uniform pressure model, the linearity of the output characteristics is good, and the signal consistency is good when used for respiratory measurement. Under the human body model, the linearity of the output characteristics is good in the middle region, but poor at both ends, which will cause deviation in respiratory measurement of underweight or overweight people. That is, under these two conditions, the measurement resolution of the respiratory signal will also be affected, thus affecting the sensitivity of respiratory signal measurement.

[0061] In the respiratory measurement device of this application, a flexible respiratory monitoring band that is in direct contact with the chest integrates a flexible piezoresistive pressure sensor. Breathing causes changes in chest pressure. Based on the electrical principle that changes in pressure cause changes in resistance, the pressure acting on the piezoresistive sensor during breathing causes resistance. Then, through a corresponding amplification circuit, the respiratory signal is collected.

[0062] Flexible piezoresistive pressure sensors can be integrated into bed sheets or mattresses, eliminating the need for separate measuring probes and devices attached to the body surface, providing a superior measurement experience. However, when using flexible piezoresistive pressure sensors in bed sheets or mattresses for respiratory measurements while the person is lying down, the static pressure exerted on the sensor varies significantly depending on the individual's weight. The higher static pressure exerted on the flexible piezoresistive pressure sensor by the lying position can prevent its output characteristics from maintaining a good linear range, thus affecting subsequent signal acquisition and processing. Without compensation, this can impact the accuracy of dynamic pressure measurements during respiration, thereby affecting the overall accuracy of respiratory measurements.

[0063] In today's society, the number of obese people is increasing, and obese individuals are generally more prone to respiratory-related diseases during sleep, thus requiring more accurate respiratory monitoring data. However, the more obese a person is, the greater the static load applied to the flexible piezoresistive pressure sensor, and the greater the difference between the output characteristic curve of the obese individual and the nominal output characteristic curve of the flexible piezoresistive pressure sensor.

[0064] Therefore, when applying flexible piezoresistive pressure sensors to respiratory measurements, the dynamic pressure detection process should be as unaffected as possible by static pressure. This ensures that even when different individuals apply varying static pressures, the dynamic pressure measurement maintains a good dynamic range and consistency. In other words, the output characteristics of the flexible piezoresistive pressure sensor should be as linear as possible to facilitate the acquisition and processing of subsequent measurement signals.

[0065] like Figure 4 In one embodiment of the pressure sensor compensation system shown, the main control module includes an MCU and an algorithm module. The algorithm module is used for sensor characteristic curve analysis and adaptive algorithms for voltage divider resistors. The signal filtering and amplification module includes a static pressure monitoring circuit. The sensor resistance compensation voltage divider module includes an analog switch, a constant voltage source excitation circuit, and a voltage divider resistor setting / voltage sensitivity adjustment circuit.

[0066] like Figure 4In one embodiment of a flexible piezoresistive sensor compensation system, the system is used to compensate the output characteristics of a flexible piezoresistive pressure sensor. It includes a main control module, a signal filtering and amplification module, and a sensor resistance compensation voltage divider module. The output terminals of the main control module and the signal filtering and amplification module are electrically connected to obtain the voltage signal output by the signal filtering and amplification module. The input terminal of the signal filtering and amplification module is electrically connected to the output terminal of an external flexible piezoresistive pressure sensor to filter and amplify the voltage signal output by the flexible piezoresistive pressure sensor after excitation by a constant voltage source. The main control module obtains the voltage output value VA of the flexible piezoresistive pressure sensor through the signal filtering and amplification module. One end of the sensor resistance compensation voltage divider module is electrically connected to the main control module to obtain a resistance setting command from the main control module and set its own resistance according to the command. The sensor resistance compensation voltage divider module as a whole acts as a resistive device connected to the external flexible piezoresistive pressure sensor. The piezoresistive pressure sensor forms a resistive voltage divider network for the signal filtering and amplification module. The sensor resistance compensation voltage divider module is also used for electrical connection to an external constant voltage source, enabling the external flexible piezoresistive pressure sensor, after being excited by the external constant voltage source, to convert the resistance change signal of the flexible piezoresistive pressure sensor into a voltage signal output. The main control module has a preset sensor characteristic curve table. Based on the acquired voltage output value VA, the main control module queries the sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor. Based on the piezoresistive sensitivity value SA, the main control module calculates the voltage divider resistance ratio of the flexible piezoresistive pressure sensor in the signal filtering and amplification module at that piezoresistive sensitivity value SA. Based on the voltage divider resistance ratio, the target voltage divider resistance value is obtained. Based on the target resistance value, the main control module sends a command to the sensor resistance compensation voltage divider module to set the compensation resistance value output by the compensation resistance module.

[0067] Before acquiring the voltage output value VA of the external flexible piezoresistive pressure sensor under static pressure A, the main control module sends a command to the sensor resistance compensation voltage divider module to set the voltage divider resistance value of the sensor resistance compensation voltage divider module to be within the upper limit range of its resistance value; the upper limit range is 0.5 to 1.5 times the open-loop resistance of the flexible force resistance sensor.

[0068] Generally, the voltage input range of the CPU's I / O pins in most main control modules is 0-VDD. To avoid the static resistance Ropen of the sensor being too large (typically on the order of 10MΩ) during initial power-up when it is in the open-loop state, if the compensation resistor R of the sensor resistance compensation voltage divider module is selected too small at this time, it will lead to an excessively large voltage divider value, which may damage the I / O pins. Therefore, it is recommended to use 0.5 to 1.5 times the open-loop resistance of the flexible force resistance sensor, or even 0.5 to 1 times the open-loop resistance of the flexible force resistance sensor.

[0069] Before calculating the voltage divider resistance ratio in the signal filtering and amplification module of the flexible piezoresistive pressure sensor under the piezoresistive sensitivity value SA, the main control module first obtains the voltage divider resistance value of the sensor resistance compensation voltage divider module.

[0070] The main control module is equipped with an AD conversion module, which is used to convert the analog signal input to the main control module from the signal filtering and amplification module into a digital signal.

[0071] like Figure 5 and Figure 6 The embodiment of the flexible piezoresistive sensor compensation circuit shown is used for compensating a flexible piezoresistive pressure sensor. It includes a signal filtering and amplification module and a sensor resistance compensation voltage divider module. The output of the signal filtering and amplification module is electrically connected to an external main control module, outputting a voltage signal to the main control module. The input of the signal filtering and amplification module is electrically connected to the output of the external flexible piezoresistive pressure sensor, filtering and amplifying the voltage signal output by the flexible piezoresistive pressure sensor after being excited by a constant voltage source. One end of the sensor resistance compensation voltage divider module is electrically connected to the external main control module, obtaining a resistance setting command from the external main control module and setting its own resistance according to the command. The sensor resistance compensation voltage divider module as a whole acts as a resistive device, forming a resistance voltage divider network with the external flexible piezoresistive pressure sensor for the signal filtering and amplification module. The sensor resistance compensation voltage divider module is also electrically connected to an external constant voltage source, so that the external flexible piezoresistive pressure sensor, after being excited by the external constant voltage source, converts the resistance change signal of the flexible piezoresistive pressure sensor into a voltage signal output. Figure 5 The RS is a piezoresistive pressure sensor.

[0072] In an embodiment of a flexible piezoresistive sensor compensation circuit device not shown in some of the accompanying drawings, the sensor resistance compensation voltage divider module includes a variable resistor whose resistance value is set according to an external command.

[0073] like Figure 6 As shown in the embodiment of a flexible piezoresistive sensor compensation circuit device, the flexible piezoresistive sensor compensation circuit device includes a sensor resistance compensation voltage divider module comprising a voltage divider resistor selection circuit and at least three voltage divider resistors; each path in the voltage divider resistor selection circuit is connected to one voltage divider resistor respectively; the voltage divider resistor selection circuit selects the corresponding voltage divider resistor to enter the circuit network according to an external command.

[0074] Figure 5As shown in the embodiment of a flexible piezoresistive sensor compensation circuit device, the voltage divider resistor gating circuit includes a multiplexer switch; the multiplexer switch includes multiple input connection terminals, each of which is electrically connected to one end of a voltage divider resistor, and the other end of the voltage divider circuit is used to be electrically connected to an external constant voltage excitation source V; the multiplexer switch includes multiple control command receiving terminals, which are used to obtain switch gating commands from the outside; the multiplexer switch includes an output terminal, which is used to be electrically connected to an output terminal of an external flexible piezoresistive pressure sensor.

[0075] like Figure 5 and Figure 6 The embodiment of the flexible piezoresistive sensor compensation circuit shown also includes a constant voltage excitation source V, which is electrically connected to a resistor voltage divider network to provide constant voltage excitation to the network. Since the sensor's output is resistance, only voltage can be acquired during actual data acquisition. Therefore, the sensor needs to be excited to output a voltage value. Two main methods for resistor excitation are constant voltage source excitation and constant current excitation. Because the open-loop output resistance of this sensor reaches the 10MΩ level, while the traditional AD acquisition range is within 5V, if constant current excitation is used, the constant current source's magnitude is only in the nA range. Constant current sources in this range have poor accuracy, low temperature stability, and are difficult to maintain in batches. Therefore, a constant voltage source is used for excitation.

[0076] In such Figure 5 In one specific embodiment shown, the current constant pressure source value is set to V0 = 5V, and the compensation resistor is Rmax = 1MΩ. When static pressure is applied, the voltage division value between the compensation resistor of the sensor resistor compensation voltage divider module and the sensor Rsensor is AD0 = 0.1V; AD0 = Rsensor / (Rsensor + Rmax) × V0. It can be calculated that Rsensor = 20kΩ. Assuming that the dynamic breathing pressure of the human body is 0.5kg, the corresponding ΔR is about 2kΩ, and the piezoresistive sensitivity SA is obtained as 2KΩ / 0.5kg = 4KΩ / kg. In order to make the output AC voltage as close as possible to the voltage acquisition center point and the output amplitude large, the compensation resistor is set to R = ΔR = 20kΩ. At this time, the effective voltage amplitude of the AC output is about 250mV.

[0077] like Figure 7In the embodiment of the signal filtering and amplification module in the flexible piezoresistive sensor compensation circuit device shown, the signal filtering and amplification module includes amplifier A, resistors R40, R41, R38, R39, capacitor C35, and capacitor C36. The positive input terminal of amplifier A is electrically connected to one end of resistor R41, and the other end of resistor R41 is electrically connected to the reference voltage terminal VREF of the amplifier. The positive input terminal of amplifier A is electrically connected to one end of capacitor C36. The other end of capacitor C36 is electrically connected to one end of capacitor C35, and the other end of capacitor C35 is used to connect to one output terminal of the piezoresistive sensor. The other end of capacitor C35 is also electrically connected to one end of resistor R40; the other end of resistor R40 is electrically connected to one end of resistor R39, and this other end of resistor R40 is also electrically connected to the output terminal of amplifier A; the other end of resistor R39 is electrically connected to the negative input terminal of amplifier A, the negative input terminal of amplifier A is connected to one end of resistor R38, and the other end of resistor R38 is electrically connected to the reference voltage terminal VREF of amplifier A; the values ​​of resistors R40, R41, R38, R39, capacitor C35, and capacitor C36, together with amplifier A, form a high-pass filter with a cutoff frequency F1 ≈ 0.1Hz. This cutoff frequency can also be adjusted according to actual usage requirements.

[0078] In one specific embodiment, the output of amplifier A is used to output a voltage signal characterizing respiration. Resistors R40 (1MΩ), R41 (1MΩ), R38 (10kΩ), R39 (10kΩ), and capacitors C35 and C36 (22uf) form a high-pass filter with amplifier A. In another specific embodiment, the values ​​of the resistors and capacitors can be as shown in the attached figure.

[0079] like Figure 7 In the embodiment of the signal filtering and amplification module in the flexible piezoresistive sensor compensation circuit device shown, the signal filtering and amplification module further includes a low-pass filter; the low-pass filter includes a resistor R42 and a capacitor C38; one end of the resistor R42 is electrically connected to the output terminal of amplifier A; the other end of the resistor R42 is electrically connected to one end of the capacitor C38, and the other end of the resistor R42 serves as the output terminal of the signal filtering and amplification module for outputting a voltage signal characterizing respiration; the other end of the capacitor C38 is grounded; in a specific embodiment, the resistor R42 is 2kΩ, the capacitor C38 is 10uF, and the low-pass filter cutoff frequency is... In another specific embodiment, the values ​​of the resistor and capacitor can be as shown in the accompanying drawings.

[0080] like Figure 7In the embodiment of the signal filtering and amplification module in the flexible piezoresistive sensor compensation circuit device shown, amplifier A is a high-precision general-purpose amplifier of model GS358; the piezoresistive sensor is a flexible integrated composite flexible micro-nano sensor of model YD-SF23-600, which includes a flexible piezoresistive pressure sensor.

[0081] Figure 8 This is a schematic diagram of the voltage signal output by the signal filtering and amplification module after compensation by the flexible piezoresistive sensor. (Example:) Figure 8 As shown, the measured voltage curve of the sensor output after compensation has good stability, which makes up for the deviation in human respiration measurement caused by light and heavy body weight. That is, under these two conditions, the consistency of the measurement resolution and sensitivity of the respiration signal is better.

[0082] Figure 9 In an embodiment of a compensation method for a flexible piezoresistive sensor, the following steps are included: Step B: Obtain the voltage output value VA of the flexible piezoresistive pressure sensor under static pressure A; Step C: Determine whether the flexible piezoresistive pressure sensor is under pressure based on the voltage output value VA obtained in Step B; if the voltage output value VA is greater than or equal to a set voltage threshold A, it is determined that pressure is acting on the flexible piezoresistive pressure sensor, and the process proceeds to Step D; if the voltage output value VA is less than the set voltage threshold A, it is determined that no pressure is acting on the flexible piezoresistive pressure sensor; Step D: ... Based on the voltage output value VA obtained in step B, consult the pre-fabricated sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor under static pressure A. Step E: Based on the piezoresistive sensitivity value SA obtained in step D, calculate the voltage divider resistance ratio between the flexible piezoresistive pressure sensor and its connected sensor resistance compensation voltage divider module. Step F: Based on the voltage divider resistance ratio calculated in step E, send a command to the sensor resistance compensation voltage divider module to set its resistance value, which participates in the voltage division of the flexible piezoresistive pressure sensor. The voltage threshold VA is used to determine whether the sensor is in an open-loop state or under stress. This threshold can be determined by the sampled AD value. Open-loop AD value = R_open_loop / (R_compensation + R_open_loop) × V ≈ 0.5VCC; AD value under stress = R_stress / (R_compensation + R_stress) × V ≈ 0.01VCC << Open-loop AD value. The specific VA can be manually calibrated according to the actual measurement.

[0083] In one embodiment of a compensation method for a flexible piezoresistive sensor, not shown in some of the accompanying drawings, the method includes step A: sending a command to the sensor resistance compensation voltage divider module to set the resistance value of the module to be within the upper limit range of its resistance value; the upper limit range is 0.5 to 1.5 times the open-loop resistance of the flexible piezoresistive sensor; before step C, step C1, determining the voltage threshold A, is also included. Before step D, a step of obtaining a pre-made sensor characteristic curve table is also included. Before step E, a step of obtaining the resistance value of the sensor resistance compensation voltage divider module is also included.

[0084] In one embodiment of a flexible piezoresistive pressure sensor not shown in the accompanying drawings, the aforementioned flexible piezoresistive sensor compensation circuit device is included.

[0085] In one embodiment of the respiratory measurement device not shown in the accompanying drawings, the above-described flexible piezoresistive sensor compensation circuit is included.

[0086] In one embodiment of the respiratory measurement system not shown in the accompanying drawings, the above-described flexible piezoresistive sensor compensation system is included.

[0087] In one embodiment of a respiratory measurement method not shown in the accompanying drawings, the above-described piezoresistive sensor compensation method is included.

[0088] In the flexible piezoresistive sensor compensation and respiratory measurement device, system, and method of this application, the sensor resistance compensation voltage divider module and the flexible piezoresistive pressure sensor form a resistance voltage divider network for the signal filtering and amplification module. The main control module, based on the acquired voltage output value VA, queries the sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor, and calculates the voltage divider resistance ratio of the flexible piezoresistive pressure sensor in the signal filtering and amplification module under this piezoresistive sensitivity value SA. Based on the voltage divider resistance ratio, a target voltage divider resistance value is calculated. Based on this target resistance value, the main control module sends a command to the sensor resistance compensation voltage divider module to set the compensation resistance value output by the compensation resistance module. This can compensate for the nonlinear characteristics of the sensor output under different pressures, making the output characteristics of the flexible piezoresistive pressure sensor more linear, facilitating subsequent signal acquisition and calculation.

[0089] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of the application specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A flexible piezoresistive sensor compensation system for respiratory measurements, characterized by, Used for output characteristic compensation of flexible piezoresistive pressure sensors. It includes a main control module, a signal filtering and amplification module, and a sensor resistance compensation voltage divider module; the output terminals of the main control module and the signal filtering and amplification module are electrically connected to obtain the voltage signal output by the signal filtering and amplification module; The input terminal of the signal filtering and amplification module is used to electrically connect to the output terminal of an external flexible piezoresistive pressure sensor, and is used to filter and amplify the voltage signal output by the flexible piezoresistive pressure sensor after being excited by a constant pressure source. The main control module obtains the voltage output value VA of the flexible piezoresistive pressure sensor through the signal filtering and amplification module; One end of the sensor resistance compensation voltage divider module is electrically connected to the main control module. It is used to obtain resistance setting instructions from the main control module and set its own resistance according to the resistance setting instructions. The sensor resistance compensation voltage divider module as a whole forms a resistance voltage divider network with the external flexible piezoresistive pressure sensor for signal filtering and amplification module. The sensor resistance compensation voltage divider module is also used to be electrically connected to an external constant voltage source, so that the external flexible piezoresistive pressure sensor connected to it can be excited by the external constant voltage source and the resistance change signal of the flexible piezoresistive pressure sensor can be converted into a voltage signal output. The main control module has a pre-made sensor characteristic curve table. Based on the obtained voltage output value VA, the main control module queries the sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor. Compensation methods for flexible piezoresistive sensors also include, Step A: Send a command to the sensor resistance compensation voltage divider module to set the resistance value of the sensor resistance compensation voltage divider module to be within the upper limit range of its resistance value; The upper limit range is 0.5 to 1.5 times the open-loop resistance of the flexible force resistance sensor; Step B: Obtain the voltage output value VA of the flexible piezoresistive pressure sensor under static pressure A; Step C: Determine whether the flexible piezoresistive pressure sensor is under pressure based on the voltage output value VA obtained in step B; Step C is preceded by step C1, which determines the voltage threshold A. If the voltage output value VA is greater than or equal to the set voltage threshold A, it is determined that there is pressure acting on the flexible piezoresistive pressure sensor, and then proceed to step D. Step D: Based on the voltage output value VA obtained in step B, consult the prefabricated sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor under static pressure A; before step D, there is also a step of obtaining the prefabricated sensor characteristic curve table. Step E: Based on the piezoresistive sensitivity value SA obtained in step D, the main control module calculates the voltage divider resistance ratio of the flexible piezoresistive pressure sensor and the sensor resistance compensation voltage divider module connected to it; before step E, the module also includes a step of obtaining the resistance value of the sensor resistance compensation voltage divider module. Based on the voltage divider ratio, the target voltage divider resistance value is obtained. Based on the target resistance value, the main control module sends a command to the sensor resistance compensation voltage divider module to set the compensation resistance value output by the compensation resistance module.

2. The flexible piezoresistive sensor compensation system for respiratory measurement according to claim 1, characterized in that, Before calculating the voltage divider resistance ratio in the signal filtering and amplification module of the flexible piezoresistive pressure sensor under the piezoresistive sensitivity value SA, the main control module first obtains the voltage divider resistance value of the sensor resistance compensation voltage divider module.

3. The flexible piezoresistive sensor compensation system for respiratory measurement according to claim 1, characterized in that, The main control module is equipped with an AD conversion module, which is used to convert the analog signal input to the main control module from the signal filtering and amplification module into a digital signal.

4. A flexible piezo-resistive sensor compensation circuit arrangement for respiratory measurements, characterized by Compensation for flexible piezoresistive pressure sensors includes, Signal filtering and amplification module and sensor resistance compensation voltage divider module; The output of the signal filtering and amplification module is used to electrically connect with the external main control module and output a voltage signal to the main control module. One end of the sensor resistance compensation voltage divider module is used to electrically connect to the external main control module to obtain resistance setting instructions from the external main control module and set its own resistance according to the resistance setting instructions; the sensor resistance compensation voltage divider module is also used to electrically connect to an external constant voltage source so that the external flexible piezoresistive pressure sensor connected to it can be excited by the external constant voltage source and the resistance change signal of the flexible piezoresistive pressure sensor can be converted into a voltage signal output. The sensor resistance compensation voltage divider module, as a whole, forms a resistance voltage divider network with the external flexible piezoresistive pressure sensor for signal filtering and amplification module, which is used as a resistive device. The input terminal of the signal filtering and amplification module is used to electrically connect to the output terminal of an external flexible piezoresistive pressure sensor, and is used to filter and amplify the voltage signal output by the flexible piezoresistive pressure sensor after being excited by a constant pressure source. Compensation methods for flexible piezoresistive pressure sensors also include, Step A: Send a command to the sensor resistance compensation voltage divider module to set the resistance value of the sensor resistance compensation voltage divider module to be within the upper limit range of its resistance value; The upper limit range is 0.5 to 1.5 times the open-loop resistance of the flexible force resistance sensor; Step B: Obtain the voltage output value VA of the flexible piezoresistive pressure sensor under static pressure A; Step C: Determine whether the flexible piezoresistive pressure sensor is under pressure based on the voltage output value VA obtained in step B; Step C is preceded by step C1, which determines the voltage threshold A. If the voltage output value VA is greater than or equal to the set voltage threshold A, it is determined that there is pressure acting on the flexible piezoresistive pressure sensor, and then proceed to step D. Step D: Based on the voltage output value VA obtained in step B, consult the prefabricated sensor characteristic curve table to obtain the piezoresistive sensitivity value SA of the flexible piezoresistive pressure sensor under static pressure A; before step D, there is also a step of obtaining the prefabricated sensor characteristic curve table. Step E: Based on the piezoresistive sensitivity value SA obtained in step D, the main control module calculates the voltage divider resistance ratio between the flexible piezoresistive pressure sensor and the sensor resistance compensation voltage divider module connected to it. Before step E, the module also includes a step of obtaining the resistance value of the sensor resistance compensation voltage divider module.

5. The flexible piezoresistive sensor compensation circuit device for respiratory measurement according to claim 4, characterized in that, The sensor resistance compensation voltage divider module includes a variable resistor, which sets its own resistance value according to external instructions.

6. The flexible piezoresistive sensor compensation circuit device for respiratory measurement according to claim 4, characterized in that, The sensor resistance compensation voltage divider module includes a voltage divider resistor gating circuit and at least three voltage divider resistors; Each path in the voltage divider resistor gating circuit is connected to a voltage divider resistor; The voltage divider resistor selection circuit selects the appropriate voltage divider resistor to enter the circuit network based on external instructions.

7. The flexible piezoresistive sensor compensation circuit device for respiratory measurement according to claim 6, characterized in that, The voltage divider resistor gating circuit includes a multi-way gating switch; The multiplexer includes multiple input terminals, each of which is electrically connected to one end of a voltage divider resistor. The other end of the voltage divider circuit is used to electrically connect to an external constant voltage excitation source V. The multiplexer includes multiple control command receiving terminals, which are used to acquire switch selection commands from the outside. The multiplexer includes an output terminal for electrical connection to an output terminal of an external flexible piezoresistive pressure sensor.

8. The flexible piezoresistive sensor compensation circuit device for respiratory measurement according to claim 4, characterized in that, It also includes a constant voltage excitation source V, which is electrically connected to the resistor voltage divider network to provide constant voltage excitation for the resistor voltage divider network.

9. The flexible piezoresistive sensor compensation circuit device for respiratory measurement according to claim 4, characterized in that, The signal filtering and amplification module is an AC voltage signal amplification circuit, including amplifier A, resistor R40, resistor R41, resistor R38, resistor R39, capacitor C35, and capacitor C36. The positive input terminal of amplifier A is electrically connected to one end of resistor R41, and the other end of resistor R41 is electrically connected to the reference voltage terminal VREF of the amplifier. The positive input terminal of amplifier A is electrically connected to one end of capacitor C36; The other end of capacitor C36 is electrically connected to one end of capacitor C35. The other end of capacitor C35 is used to be electrically connected to one output terminal of the piezoresistive sensor. The other end of capacitor C35 is also electrically connected to one end of resistor R40. The other end of resistor R40 is electrically connected to one end of resistor R39, and the other end of resistor R40 is also electrically connected to the output terminal of amplifier A; the other end of resistor R39 is electrically connected to the negative input terminal of amplifier A, the negative input terminal of amplifier A is connected to one end of resistor R38, and the other end of resistor R38 is electrically connected to the reference voltage terminal VREF of amplifier A; the output terminal of amplifier A is used to output a voltage signal characterizing respiration. The resistance R40, resistance R41, resistance R38, resistance R39, capacitance C35 and capacitance C36 are valued, and a high-pass filter composed of the amplifier A makes its cutoff frequency F1= .

10. The flexible piezoresistive sensor compensation circuit device for respiratory measurement according to claim 9, characterized in that, The signal filtering and amplification module further includes a low-pass filter; the low-pass filter includes a resistor R42 and a capacitor C38; one end of the resistor R42 is electrically connected to the output terminal of amplifier A; the other end of the resistor R42 is electrically connected to one end of the capacitor C38, and the other end of the resistor R42 is used as the output terminal of the signal filtering and amplification module to output a voltage signal characterizing breathing; the other end of the capacitor C38 is grounded. The resistor R42 has a value of 2kΩ. The capacitor C38 has a value of 10uF, and the low-pass filter cutoff frequency F2 = .

11. The flexible piezoresistive sensor compensation circuit device for respiratory measurement according to claim 9, characterized in that, The amplifier A is a high-precision general-purpose amplifier of model GS358; The piezoresistive sensor is a flexible integrated composite flexible micro-nano sensor with model number YD-SF23-600, which includes a flexible piezoresistive pressure sensor.

12. A flexible piezoresistive pressure sensor, characterized in that, Includes the flexible piezoresistive sensor compensation circuit device for respiratory measurement as described in any one of claims 4 to 11 above.

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