Kama alloy strain gauge and heart rate detection method and device

Abstract

The invention discloses a Kama alloy strain gauge and a heart rate detection method and device, and relates to the technical field of heart rate detection strain gauges. The Kama alloy strain gauge of the present invention is attached to the skin of an organism during use, and comprises: a second layer comprising a metal strain gauge layer; the third layer comprises a piezoelectric material layer; and the first layer comprises a Kama alloy layer. On the basis of a Kama alloy strain gauge, a metal strain gauge is overlaid to sense a noise signal caused by non-heart-rate change movement of the skin of an organism, and a piezoelectric material layer comprising a piezoelectric material is overlaid to provide feedback adjustment and drive a Kama alloy layer to reversely deform, so that the noise is reduced; the influence caused by non-heart rate change movement of the organism skin is offset from the physical angle, so that the accuracy of heart rate monitoring is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heart rate detection strain gauges, and in particular to a kama alloy strain gauge, a heart rate detection method and a device. Background Art

[0002] Heart rate and pulse detection technology is a key research area in biomedical sensing and health monitoring, with widespread applications in clinical medicine, sports health monitoring, and home healthcare. Karma alloy strain gauges, with their high sensitivity (strain sensitivity coefficient >2000), low temperature coefficient, and excellent fatigue resistance, offer unique advantages in biomechanical signal detection. In this area, Karma alloy strain gauges can be used to measure the tiny deformations caused by vascular pulsation, enabling high-precision pulse wave signal acquisition. Compared to traditional metal strain gauges (such as Constantan), Karma alloy offers an order of magnitude improvement in temperature stability, giving it significant potential for wearable health monitoring. Furthermore, advancements in flexible electronics technology allow Karma alloy strain gauges to be integrated with flexible substrates (such as PDMS), enabling highly conformable monitoring of the skin.

[0003] However, when using Kama alloy strain gauges to detect heart rate, other movements of the organism will also cause deformation of the strain gauge, such as breathing, walking, running, and relaxation of the skin to adapt to the temperature. The aforementioned non-heart rate-changing movements of the organism's skin will have an adverse effect on heart rate detection. Eliminating the above-mentioned influences solely from the perspective of data processing is not ideal. Therefore, it is necessary to design a new Kama alloy strain gauge and a corresponding method of use to reduce the adverse effects of non-heart rate-changing movements of the organism's skin on heart rate detection and improve the accuracy of heart rate monitoring. Summary of the Invention

[0004] The present invention provides a kama alloy strain gauge, a heart rate detection method and a device, which are used to reduce the adverse effects of non-heart rate-changing movements of the skin of an organism on heart rate detection and improve the accuracy of heart rate monitoring.

[0005] In order to solve the above technical problems, the first aspect of the present invention discloses a heart rate detection method based on a Kama alloy strain gauge, wherein the Kama alloy strain gauge includes at least a first layer, a second layer and a third layer, wherein the first layer includes a Kama alloy layer, the second layer includes a metal strain gauge layer, and the third layer includes a piezoelectric material layer. The method includes: Obtaining a second output signal of the second layer of the kama alloy strain gauge attached to the skin of the organism, and determining whether a target signal exists in the second output signal, the target signal including a signal generated by deformation of the second layer caused by non-heart rate-varying movement of the skin of the organism; If it is determined that the second output signal contains a target signal, determining a third input signal for deforming the third layer according to the target signal; inputting the third input signal to the third layer, so that the third layer drives the second layer and the first layer to undergo corresponding deformation; A first output signal of the first layer is acquired, and heart rate information of the biological body is obtained according to the first output signal.

[0006] As an optional embodiment, in the first aspect of the present invention, the strain sensitivity coefficient of the second layer is lower than the strain sensitivity coefficient of the first layer, and the strain sensitivity coefficient represents the degree of resistance change of the strain gauge with deformation.

[0007] As an optional embodiment, in the first aspect of the present invention, the second output signal is a voltage signal or a current signal, and the determining whether the target signal exists in the second output signal includes: determining, based on the second output signal, a change relationship between the second output signal and time, wherein the change relationship is used to represent a change of the second output signal over time; It is determined whether the change relationship corresponds to a preset change relationship. If it is determined that the change relationship corresponds to the preset change relationship, it is determined that a target signal exists in the second output signal.

[0008] As an optional implementation manner, in the first aspect of the present invention, determining whether the change relationship corresponds to a preset change relationship includes: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, wherein the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; Inputting the second output signal-time variation curve into a pre-trained target signal analysis model, wherein the target signal analysis model is obtained by training multiple sets of signal-time variation curves and is used to analyze whether the input signal-time variation curve conforms to a preset target linear shape; If the target signal analysis model analyzes that the second output signal-time variation curve conforms to the target linear shape, it is determined that the variation relationship corresponds to a preset variation relationship.

[0009] As an optional implementation manner, in the first aspect of the present invention, determining that the change relationship corresponds to the preset change relationship includes: determining that the change relationship indicates that the voltage value of the second output signal is continuously greater than or equal to a preset voltage threshold value within a preset time length, or that the current value of the second output signal is continuously greater than or equal to a preset current threshold value within a preset time length, then determining that the change relationship corresponds to the preset change relationship; And, determining a third input signal for deforming the third layer according to the target signal includes: determining a voltage value or a current value of the second output signal as a target signal; A third input signal for causing the third layer to deform is determined based on the voltage value or current value corresponding to the target signal. The third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

[0010] As an optional implementation manner, in the first aspect of the present invention, determining that the change relationship corresponds to the preset change relationship includes: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, wherein the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; If it is determined that a preset corresponding relationship exists between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer, then it is determined that the variation relationship corresponds to the preset variation relationship; And, determining a third input signal for deforming the third layer according to the target signal includes: determining the second output signal-time variation curve as a target signal; The frequency of the third input signal used to cause the third layer to deform is determined according to the frequency corresponding to the target signal, and the amplitude of the third input signal used to cause the third layer to deform is determined according to the amplitude corresponding to the target signal; the third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

[0011] As an optional implementation manner, in the first aspect of the present invention, determining that there is a preset correspondence between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer includes: determining a frequency of the second output signal-time variation curve as a second frequency, and determining a frequency of the first output signal of the first layer as a first frequency; If it is determined that the first frequency is an integer multiple of the second frequency, or the second frequency is an integer multiple of the first frequency, then it is determined that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer.

[0012] A second aspect of the present invention discloses a Kama alloy strain gauge, characterized in that the Kama alloy strain gauge is attached to the skin of a living body when in use, and the Kama alloy strain gauge comprises: A second layer comprising a metal strain gauge layer; the second layer is used to obtain a second output signal; The third layer includes a piezoelectric material layer; the third layer is used to obtain a third input signal and drive the second layer and the first layer to undergo corresponding deformation according to the third input signal; A first layer includes a Kama alloy layer; the first layer is used to obtain a first output signal, and the first output signal is used to obtain heart rate information of the organism; Among them, the third input signal is a signal determined based on the target signal when it is determined that there is a target signal in the second output signal, and the target signal includes a signal generated by the deformation of the second layer caused by non-heart rate change movement of the biological skin.

[0013] As an optional embodiment, in the second aspect of the present invention, the strain sensitivity coefficient of the second layer is lower than the strain sensitivity coefficient of the first layer, and the strain sensitivity coefficient represents the degree of resistance change of the strain gauge with deformation.

[0014] A third aspect of the present invention discloses a heart rate detection device based on a Kama alloy strain gauge, characterized in that the Kama alloy strain gauge includes at least a first layer, a second layer, and a third layer, wherein the first layer includes a Kama alloy layer, the second layer includes a metal strain gauge layer, and the third layer includes a piezoelectric material layer. The device includes: a second acquisition module, configured to acquire a second output signal of the second layer of the kama alloy strain gauge attached to the skin of the organism, and determine whether a target signal exists in the second output signal, wherein the target signal includes a signal generated by deformation of the second layer caused by non-heart rate-varying movement of the organism's skin; a signal analysis module configured to, when determining that a target signal exists in the second output signal, determine a third input signal for causing the third layer to deform according to the target signal; a signal output module, configured to input the third input signal to the third layer, so that the third layer drives the second layer and the first layer to undergo corresponding deformation; The first acquisition module is used to acquire the first output signal of the first layer and obtain the heart rate information of the organism according to the first output signal.

[0015] As an optional embodiment, in the third aspect of the present invention, the second output signal is a voltage signal or a current signal, and the specific manner in which the second acquisition module determines whether the target signal exists in the second output signal includes: determining, based on the second output signal, a change relationship between the second output signal and time, wherein the change relationship is used to represent a change of the second output signal over time; It is determined whether the change relationship corresponds to a preset change relationship. If it is determined that the change relationship corresponds to the preset change relationship, it is determined that a target signal exists in the second output signal.

[0016] As an optional implementation manner, in the third aspect of the present invention, the specific manner in which the second acquisition module determines whether the change relationship corresponds to a preset change relationship includes: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, wherein the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; Inputting the second output signal-time variation curve into a pre-trained target signal analysis model, wherein the target signal analysis model is obtained by training multiple sets of signal-time variation curves and is used to analyze whether the input signal-time variation curve conforms to a preset target linear shape; If the target signal analysis model analyzes that the second output signal-time variation curve conforms to the target linear shape, it is determined that the variation relationship corresponds to a preset variation relationship.

[0017] As an optional implementation manner, in the third aspect of the present invention, the specific manner in which the second acquisition module determines that the change relationship corresponds to the preset change relationship includes: determining that the change relationship indicates that the voltage value of the second output signal is continuously greater than or equal to a preset voltage threshold value within a preset time length, or that the current value of the second output signal is continuously greater than or equal to a preset current threshold value within a preset time length, then determining that the change relationship corresponds to the preset change relationship; Furthermore, the signal analysis module determines a specific method of a third input signal for causing the third layer to deform according to the target signal, including: determining a voltage value or a current value of the second output signal as a target signal; A third input signal for causing the third layer to deform is determined based on the voltage value or current value corresponding to the target signal. The third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

[0018] As an optional implementation manner, in the third aspect of the present invention, the specific manner in which the second acquisition module determines that the change relationship corresponds to the preset change relationship includes: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, wherein the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; If it is determined that a preset corresponding relationship exists between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer, then it is determined that the variation relationship corresponds to the preset variation relationship; Furthermore, the signal analysis module determines a specific method of a third input signal for causing the third layer to deform according to the target signal, including: determining the second output signal-time variation curve as a target signal; The frequency of the third input signal used to cause the third layer to deform is determined according to the frequency corresponding to the target signal, and the amplitude of the third input signal used to cause the third layer to deform is determined according to the amplitude corresponding to the target signal; the third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

[0019] As an optional implementation manner, in the third aspect of the present invention, the specific manner in which the second acquisition module determines whether there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer includes: determining a frequency of the second output signal-time variation curve as a second frequency, and determining a frequency of the first output signal of the first layer as a first frequency; If it is determined that the first frequency is an integer multiple of the second frequency, or the second frequency is an integer multiple of the first frequency, then it is determined that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention relates to a kama alloy strain gauge that is attached to the skin of a living organism when in use. The kama alloy strain gauge comprises: a second layer comprising a metal strain gauge layer; the second layer is configured to obtain a second output signal; a third layer comprising a piezoelectric material layer; the third layer is configured to obtain a third input signal and, based on the third input signal, drive the second and first layers to undergo corresponding deformations; and a first layer comprising a kama alloy layer; the first layer is configured to obtain a first output signal, the first output signal being used to obtain heart rate information of the living organism; wherein the third input signal is a signal determined based on the target signal when a target signal is determined to be present in the second output signal, the target signal comprising a signal generated by deformation of the second layer caused by non-heart rate-varying movement of the living organism's skin. The present invention, based on the kama alloy strain gauge, superimposes a metal strain gauge for sensing noise signals caused by non-heart rate-varying movement of the living organism's skin, and further superimposes a piezoelectric material layer comprising a piezoelectric material for providing feedback regulation, driving the kama alloy layer to deform in the opposite direction, thereby physically offsetting the effects of non-heart rate-varying movement of the living organism's skin, thereby improving the accuracy of heart rate monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 Schematic diagram of the structure of a Kama alloy strain gauge disclosed in an embodiment of the present invention; Figure 2 1 is a flow chart of a heart rate detection method based on a Kama alloy strain gauge disclosed in an embodiment of the present invention; Figure 3 This is a structural schematic diagram of a heart rate detection device based on a Kama alloy strain gauge disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0024] The terms "first," "second," and so on, in the description and claims of the present invention and the accompanying drawings are used to distinguish between different items, not to describe a specific order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or end comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or end.

[0025] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] Example 1 Metal strain gauges operate based on the resistance strain effect. When a metal conductor undergoes mechanical deformation (stretching or compressing) under external force, its resistance changes accordingly. This is because the resistance R of a metal conductor is related to its length L, cross-sectional area A, and resistivity ρ, using the relationship R = ρL / A. When a metal strain gauge is attached to the surface of an object being measured, the object's strain causes the gauge's sensitive grid (the part of the metal strain gauge that primarily changes resistance, typically a grid-like structure made of very fine metal wire or foil) to deform. For example, under tensile strain, the sensitive grid length increases, the cross-sectional area decreases, and the resistivity also changes slightly, resulting in an increase in resistance. By measuring this change in resistance, the strain of the object being measured can be determined.

[0027] The change in resistance of a strain gauge with deformation is called the strain sensitivity coefficient, denoted by the symbol "k." Its calculation formula is: k = (ΔR / R) / ε. Here, ΔR is the change in resistance of the strain gauge, R is the initial resistance of the strain gauge, and ε is the strain (i.e., the amount of deformation per unit length). For example, if a strain gauge has an initial resistance R of 120Ω and is subjected to a strain ε of 500με (microstrain), the resistance change ΔR is 0.24Ω. Therefore, the strain sensitivity coefficient k = (0.24 / 120) / 500 × 10^{-6} = 4. This indicates that the resistance change of this strain gauge is highly sensitive to strain.

[0028] Strain gauges made of different materials and structures have different strain sensitivity coefficients. Generally speaking, the strain sensitivity coefficient of metal strain gauges is about 2-3, while the strain sensitivity coefficient of semiconductor strain gauges is relatively large, possibly reaching 100-200, and the strain sensitivity coefficient of Kama alloy is >2000.

[0029] When in use, the strain gauge is attached to the skin of a living organism. The skin can move with changes in heart rate, but at the same time, other movements of the living organism can also cause the strain gauge to deform, such as breathing, walking, running, and the relaxation of the skin to adapt to the temperature. The aforementioned non-heart rate-related movements of the living organism's skin will have an adverse effect on heart rate detection.

[0030] Using algorithms alone to filter out noise from strain gauge data that is not caused by heart rate-related skin movement is difficult for the following reasons: (1) For some large-scale skin changes, such as large-scale movements of the organism, skin contraction caused by cold, etc., the strain gauge often has an optimal expansion and contraction range. Large-scale skin movement will pull the strain gauge out of this optimal range, resulting in reduced detection accuracy.

[0031] (2) The noise generated by many non-heart rate-varying movements of the skin has a certain degree of volatility, that is, it has a frequency. This frequency-varying signal is loaded on the heart rate signal, making the separation of the two more difficult. In particular, when the frequency of the noise and the frequency of the heart rate data have a certain numerical relationship and cause "resonance", it is basically impossible to obtain the noise data simply through the algorithm.

[0032] Therefore, one of the inventive concepts of the present invention is: on the basis of the Kama alloy strain gauge, a metal strain gauge is superimposed (the strain sensitivity coefficient can be lower, so as to match the noise signal with larger amplitude changes), and then a piezoelectric material layer including piezoelectric material is superimposed. The metal strain gauge layer is used to sense the noise signal caused by the non-heart rate change movement of the biological skin, and the piezoelectric material layer is used to provide feedback regulation to drive the Kama alloy layer to reverse deformation, thereby offsetting the impact of the non-heart rate change movement of the biological skin from a physical perspective.

[0033] Based on the above invention concept, the embodiment of the present invention discloses a Kama alloy strain gauge, such as Figure 1 As shown, the Kama alloy strain gauge is attached to the skin of a biological body when in use. The Kama alloy strain gauge may include: The second layer includes a metal strain gauge layer, wherein the second layer is used to obtain a second output signal, which is also the output signal of the metal strain gauge. It is well known to those skilled in the art that a corresponding circuit, such as a bridge circuit, can be set to convert the deformation of the metal strain gauge into an electrical signal such as current or voltage to obtain an output signal.

[0034] The third layer includes a piezoelectric material layer, and the third layer is used to obtain a third input signal and drive the second layer and the first layer to undergo corresponding deformation according to the third input signal; wherein the third input signal is a signal determined according to the target signal when it is determined that there is a target signal in the second output signal, and the target signal includes a signal generated by the deformation of the second layer caused by non-heart rate change movement of the biological skin.

[0035] In this embodiment of the present invention, the target signal includes a signal generated by deformation of the second layer of the skin caused by non-heart rate-dependent movement. This can include a signal with a large signal value due to large-amplitude movement, or a signal with a certain frequency value due to specific frequency changes in the skin. Both of these signals generated by deformation of the second layer of the skin caused by non-heart rate-dependent movement are noise signals. In this embodiment of the present invention, the second layer can sense and identify these noise signals.

[0036] The device includes a first layer of a kama alloy layer, the first layer being used to obtain a first output signal, and the first output signal being used to obtain heart rate information of a living body. It is well known to those skilled in the art that a corresponding circuit can be designed, such as a bridge circuit, to obtain deformation of the kama alloy layer caused by skin movement driven by the heart rate, and convert this deformation into a current or voltage signal. Based on the current or voltage signal, the heart rate information contained in the current or voltage signal can then be analyzed.

[0037] In the embodiment of the present invention, the first layer, the second layer and the third layer are not limited to a specific layer order. For example, the first layer can be a layer that directly contacts the skin, or it can be a middle or last layer.

[0038] It can be seen that in the embodiment of the present invention, on the basis of the Kama alloy strain gauge, a metal strain gauge is superimposed to sense the noise signal caused by the non-heart rate change movement of the biological skin, and then a piezoelectric material layer including piezoelectric material is superimposed to provide feedback regulation, thereby driving the Kama alloy layer to deform in the opposite direction, thereby offsetting the impact of the non-heart rate change movement of the biological skin from a physical perspective, thereby improving the accuracy of heart rate monitoring.

[0039] In an optional embodiment, the strain sensitivity coefficient of the second layer is lower than the strain sensitivity coefficient of the first layer, and the strain sensitivity coefficient represents the degree of resistance change of the strain gauge as the strain gauge changes with deformation.

[0040] In this application, the first layer is used to sense heart rate data, and the second layer is used to sense noise data. Noise data is often much larger than heart rate data. Therefore, the strain sensitivity coefficient of the second layer is lower than that of the first layer. It can also be seen that the strain sensitivity coefficient of the second layer is set to only sense noise data but not heart rate data. Through the above design, in this application, the second layer and the first layer are matched with different skin movement data respectively, so as to better play their respective roles. In particular, the second layer can be used specifically to sense noise data, better separating heart rate data from noise data from a physical perspective.

[0041] For strain gauges, their main structures can include: 1. Sensitive grid The sensitive grid is the core component of a metal strain gauge. It's typically made of materials with high strain sensitivity and excellent stability, such as constantan, bare copper, and nickel-chromium alloy. Sensitive grids come in a variety of shapes, with the most common being point-type and fence-type. Point-type sensitive grids resemble a small rectangular grid, effectively sensing strain within a smaller area; fence-type sensitive grids resemble parallel metal "fences," enabling measurement of strain over a wider range.

[0042] 2. Base The substrate's primary function is to attach the sensitive grid to the surface of the object being measured, while also insulating and protecting it. Materials such as polyimide and polyester film are commonly used. These materials offer excellent flexibility, adapting to the shape of the surface being measured. They also provide excellent electrical insulation, preventing short circuits between the sensitive grid and other conductive objects.

[0043] 3. Covering layer The cover layer covers the sensitive grid and the substrate, further protecting the sensitive grid from external environmental factors (such as moisture, corrosive gases, mechanical damage, etc.). Similar to the substrate material, it is also made of a material with good insulation properties, such as epoxy resin and other coating materials.

[0044] 4. Lead wire Lead wires connect the metal strain gauge to the measurement circuit. Typically, a highly conductive metal wire, such as copper, is used. One end is welded to the lead-out terminal of the sensitive grid, and the other end is connected to the measuring instrument to transmit the resistance change signal.

[0045] For strain gauges, the main types can include: 1. Foil strain gauge The sensitive grid of a foil strain gauge is made of metal foil. This metal foil is processed into the desired grid shape through processes such as photolithography and etching. This type of strain gauge offers advantages such as high sensitivity, compact size, and the ability to measure localized strain. Furthermore, it offers excellent mass production performance and high consistency. For example, when measuring strain in tiny mechanical structures, foil strain gauges can be precisely bonded to the surface of the component, accurately measuring its strain.

[0046] 2. Wire strain gauge The sensitive grid of a wire strain gauge is wound with metal wire. This wire is typically a very fine resistance alloy wire, such as constantan wire. Its advantages include high mechanical strength and the ability to withstand large strains. However, due to factors such as wire diameter and the winding process, its dimensional accuracy and sensitivity may not be as good as those of foil strain gauges. Wire strain gauges are often used in applications requiring high mechanical strength, such as strain measurement in large structural components.

[0047] 3. Thin film strain gauge The sensitive grid of a thin-film strain gauge is formed by forming a thin metal film on a substrate through processes such as vacuum coating, and then forming a grid pattern through processes such as photolithography. This type of strain gauge has high sensitivity and good frequency response characteristics, making it suitable for dynamic strain measurement. For example, when measuring rapid strain changes caused by vibration, thin-film strain gauges can respond quickly and accurately measure the strain signal.

[0048] In this optional embodiment, the second layer is a metal strain gauge, which can be a strain gauge of other metals or alloys other than Kama alloy, or it can be set to the same Kama alloy strain gauge as the first layer. It is only necessary to make the structures of the two different, such as the density of the sensitive grid is different, so that the strain sensitivity coefficients of the two are different.

[0049] In an embodiment of the present invention, the third layer is a piezoelectric material layer, wherein the piezoelectric material is a material that deforms when a voltage is applied, such as an electrostrictive material.

[0050] In an optional embodiment, the third layer is made of polyvinylidene fluoride (PVDF) or its copolymers. PVDF molecular chains contain highly electronegative fluorine atoms. Under the influence of an electric field, the polar groups in the molecular chains align, causing the material to expand and contract. This material exhibits excellent flexibility and mechanical properties, and has promising applications in flexible sensors and actuators.

[0051] Example 2 See also Figure 2 , Figure 2 This is a flow chart of a heart rate detection method based on a Kama alloy strain gauge disclosed in an embodiment of the present invention. Figure 1The described heart rate detection method based on the Kama alloy strain gauge can be applied to a heart rate detection device based on the Kama alloy strain gauge. The heart rate detection device based on the Kama alloy strain gauge can be integrated into a cloud server or a local server, and the embodiment of the present invention is not limited thereto. The Kama alloy strain gauge includes at least a first layer, a second layer, and a third layer, wherein the first layer includes a Kama alloy layer, the second layer includes a metal strain gauge layer, and the third layer includes a piezoelectric material layer, such as Figure 1 As shown, the heart rate detection method based on the Kama alloy strain gauge may include the following operations: Step 101: Obtain a second output signal of a second layer of a Kama alloy strain gauge attached to the skin of a biological subject, and determine whether a target signal exists in the second output signal.

[0052] In the embodiment of the present invention, the target signal may include a signal generated by deformation of the second layer of the biological skin caused by non-heart rate variation movement.

[0053] In an optional embodiment, the second output signal is a voltage signal or a current signal, and determining whether the target signal exists in the second output signal may include: determining, based on the second output signal, a change relationship between the second output signal and time, the change relationship being used to represent a change of the second output signal over time; It is determined whether the change relationship corresponds to a preset change relationship. If it is determined that the change relationship corresponds to the preset change relationship, it is determined that the target signal exists in the second output signal.

[0054] For example, the target signal may include a signal with a large signal value due to large-scale movement of the organism, or a signal with a certain frequency value due to a specific frequency change in the organism's skin. Both of these signals, caused by the deformation of the second layer due to non-heart rate-related movement of the organism's skin, are noise signals. In embodiments of the present invention, these noise signals can be sensed and identified through the second layer.

[0055] Step 102: If it is determined that the second output signal contains a target signal, a third input signal for deforming the third layer is determined according to the target signal.

[0056] In an embodiment of the present invention, if it is determined that a target signal exists in the second output signal, it means that the second layer has sensed a noise signal. In this case, it is necessary to send a corresponding feedback adjustment signal to the second layer to cause the first and second layers to deform, thereby physically canceling the noise signal. Since the target signal may include a signal with a large signal value due to large-scale movement of the organism, or a signal with a certain frequency value due to a specific frequency change in the skin of the organism, the third input signal also includes a signal of a certain value or a signal of a certain frequency. Specifically, the third input signal is obtained by analyzing the second output signal. For example, a corresponding relationship can be preset, and once the second output signal meets certain conditions, the output of the corresponding third input signal is immediately triggered.

[0057] Step 103: Input a third input signal to the third layer.

[0058] In an embodiment of the present invention, a third input signal is input to the third layer, causing the third layer to cause the second and first layers to undergo corresponding deformations. For example, if a biological skin undergoes a significant movement, causing the first layer to stretch significantly, the third layer can reversely adjust to pull the first layer back to its original length, thereby reducing the adverse effects of non-heart rate-related movements of the biological skin on heart rate detection and improving the accuracy of heart rate monitoring. For another example, if a biological skin changes with respiration in addition to heart rate, the second layer can precisely sense these changes caused by respiration, and the third layer can offset these changes caused by respiration through feedback adjustment, thereby reducing the adverse effects of non-heart rate-related movements of the biological skin on heart rate detection and improving the accuracy of heart rate monitoring.

[0059] Step 104: Acquire a first output signal of the first layer, and obtain heart rate information of the organism according to the first output signal.

[0060] It is well known to those skilled in the art that corresponding circuits can be designed, such as a bridge circuit, to obtain the deformation of the kama alloy layer as the skin moves driven by the heart rate, and convert this deformation into a current or voltage signal, and then based on the current or voltage signal, analyze the heart rate information contained in the current or voltage signal.

[0061] In the embodiment of the present invention, the first layer, the second layer and the third layer are not limited to a specific layer order. For example, the first layer can be a layer that directly contacts the skin, or it can be a middle or last layer.

[0062] It can be seen that in the embodiment of the present invention, on the basis of the Kama alloy strain gauge, a metal strain gauge is superimposed to sense the noise signal caused by the non-heart rate change movement of the biological skin, and then a piezoelectric material layer including piezoelectric material is superimposed to provide feedback regulation, thereby driving the Kama alloy layer to deform in the opposite direction, thereby offsetting the impact of the non-heart rate change movement of the biological skin from a physical perspective, thereby improving the accuracy of heart rate monitoring.

[0063] In the first embodiment of the present invention, the target signal includes a signal generated by deformation of the second layer of the biological subject's skin caused by non-heart rate-dependent movement. Identifying the target signal is crucial to the implementation of the present invention. The principle behind identifying the target signal in this embodiment of the present invention is to determine whether the change relationship corresponds to a preset change relationship.

[0064] In order to better identify the target signal, in an optional embodiment, determining whether the change relationship corresponds to a preset change relationship may include: According to the changing relationship between the second output signal and time, a second output signal-time changing curve is fitted. The second output signal-time changing curve is used to fit the corresponding relationship between the second output signal and time. Through curve fitting, the information contained in the second output signal can be better mined.

[0065] Inputting the second output signal-time variation curve into a pre-trained target signal analysis model, wherein the target signal analysis model is obtained by training multiple sets of signal-time variation curves and is used to analyze whether the input signal-time variation curve conforms to a preset target linear shape; If the target signal analysis model analyzes that the second output signal-time variation curve conforms to the target linear shape, it is determined that the variation relationship corresponds to the preset variation relationship.

[0066] This optional embodiment uses a preset model to analyze whether the second output signal-time change curve conforms to the target linear shape, and can more intelligently and accurately determine whether the change relationship corresponds to the preset change relationship, thereby more accurately identifying the target signal.

[0067] In embodiments of the present invention, target signals can include signals with large signal values ​​due to large-scale movement of an organism, or signals with certain frequency values ​​due to specific frequency changes in the organism's skin. For each of these two types of signals, corresponding schemes can be set up to identify the target signal. However, the following two schemes can also be combined or integrated to achieve better results.

[0068] In an optional embodiment, for a signal with a large signal value generated by a large-amplitude movement of a biological body, determining that the change relationship corresponds to a preset change relationship may include: Determining that the change relationship indicates that the voltage value of the second output signal is continuously greater than or equal to a preset voltage threshold value within a preset time length, or that the current value of the second output signal is continuously greater than or equal to a preset current threshold value within a preset time length, then determining that the change relationship corresponds to the preset change relationship; And, determining, based on the target signal, a third input signal for causing the third layer to deform may include: Determine the voltage value or current value of the second output signal as a target signal; A third input signal for causing the third layer to deform is determined based on the voltage value or current value corresponding to the target signal. The third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

[0069] In this optional embodiment, a corresponding voltage threshold or current threshold is set for signals with large signal values ​​generated by large-scale movement of the organism. Once the second signal is continuously greater than or equal to the threshold within a certain time range, it is determined that a signal with a large signal value due to large-scale movement of the organism has occurred. In this case, the magnitude of the third input signal is determined based on the voltage or current value of the second output signal. For example, the corresponding relationship between the voltage or current value of the second output signal and the magnitude of the third input signal can be preset in advance, so that the third input signal used to cause deformation of the third layer can be quickly determined based on the voltage or current value corresponding to the target signal.

[0070] In another optional embodiment, for a signal having a certain frequency value caused by a specific frequency change in the skin of a biological body, determining that the change relationship corresponds to a preset change relationship may include: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, and the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; If it is determined that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer, then it is determined that the variation relationship corresponds to the preset variation relationship; And, determining, based on the target signal, a third input signal for causing the third layer to deform may include: determining the second output signal-time variation curve as a target signal; The frequency of the third input signal used to deform the third layer is determined according to the frequency corresponding to the target signal, and the amplitude of the third input signal used to deform the third layer is determined according to the amplitude corresponding to the target signal; the third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

[0071] In this optional embodiment, for a signal with a certain frequency value caused by a specific frequency change in the skin of a biological body, the signal often has a certain corresponding relationship with the heart rate signal, resulting in resonance between the two, making it difficult to use other means to separate the heart rate signal and the noise signal.

[0072] In this optional embodiment, further optionally, determining whether a preset corresponding relationship exists between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer may include: The frequency of the second output signal-time variation curve is defined as a second frequency, and the frequency of the first output signal of the first layer is defined as a first frequency; If it is determined that the first frequency is an integer multiple of the second frequency, or the second frequency is an integer multiple of the first frequency, then it is determined that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer.

[0073] Example 3 The embodiment of the present invention discloses a heart rate detection device based on a Kama alloy strain gauge. Figure 3 As shown, the Kama alloy strain gauge includes at least a first layer, a second layer and a third layer, wherein the first layer includes a Kama alloy layer, the second layer includes a metal strain gauge layer, and the third layer includes a piezoelectric material layer. The device may include: A second acquisition module 201 is configured to acquire a second output signal of a second layer of the kama alloy strain gauge attached to the skin of a living being, and determine whether a target signal exists in the second output signal, wherein the target signal includes a signal generated by deformation of the second layer of the living being caused by non-heart rate-related movement of the skin; a signal analysis module 202 for determining, when determining that a target signal exists in the second output signal, a third input signal for causing the third layer to deform based on the target signal; The signal output module 203 is configured to input a third input signal to the third layer, so that the third layer drives the second layer and the first layer to undergo corresponding deformations; The first acquisition module 204 is configured to acquire a first output signal of the first layer and obtain heart rate information of the organism according to the first output signal.

[0074] In an optional embodiment, the second output signal is a voltage signal or a current signal, and the specific manner in which the second acquisition module 201 determines whether the target signal exists in the second output signal includes: determining, based on the second output signal, a change relationship between the second output signal and time, the change relationship being used to represent a change of the second output signal over time; It is determined whether the change relationship corresponds to a preset change relationship. If it is determined that the change relationship corresponds to the preset change relationship, it is determined that the target signal exists in the second output signal.

[0075] In another optional embodiment, the specific manner in which the second obtaining module 201 determines whether the change relationship corresponds to the preset change relationship includes: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, and the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; Inputting the second output signal-time variation curve into a pre-trained target signal analysis model, wherein the target signal analysis model is obtained by training multiple sets of signal-time variation curves and is used to analyze whether the input signal-time variation curve conforms to a preset target linear shape; If the target signal analysis model analyzes that the second output signal-time variation curve conforms to the target linear shape, it is determined that the variation relationship corresponds to the preset variation relationship.

[0076] In another optional embodiment, the specific manner in which the second obtaining module 201 determines whether the change relationship corresponds to the preset change relationship includes: Determining that the change relationship indicates that the voltage value of the second output signal is continuously greater than or equal to a preset voltage threshold value within a preset time length, or that the current value of the second output signal is continuously greater than or equal to a preset current threshold value within a preset time length, then determining that the change relationship corresponds to the preset change relationship; Furthermore, the signal analysis module 202 determines a specific method of the third input signal for deforming the third layer according to the target signal, including: Determine the voltage value or current value of the second output signal as a target signal; A third input signal for causing the third layer to deform is determined based on the voltage value or current value corresponding to the target signal. The third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

[0077] In another optional embodiment, the specific manner in which the second obtaining module 201 determines whether the change relationship corresponds to the preset change relationship includes: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, and the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; If it is determined that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer, then it is determined that the variation relationship corresponds to the preset variation relationship; Furthermore, the signal analysis module 202 determines a specific method of the third input signal for deforming the third layer according to the target signal, including: determining the second output signal-time variation curve as a target signal; The frequency of the third input signal used to deform the third layer is determined according to the frequency corresponding to the target signal, and the amplitude of the third input signal used to deform the third layer is determined according to the amplitude corresponding to the target signal; the third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

[0078] In another optional embodiment, the second acquisition module 201 determines that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer by: Determine the frequency of the second output signal-time variation curve as the second frequency, and the frequency of the first output signal of the first layer as the first frequency; If it is determined that the first frequency is an integer multiple of the second frequency, or the second frequency is an integer multiple of the first frequency, then it is determined that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer.

[0079] The device embodiments described above are merely illustrative, wherein the modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, i.e., they may be located in one place or distributed across multiple network modules. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Those skilled in the art can understand and implement the present invention without inventive effort.

[0080] Through the detailed description of the above embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the existing technology, can be embodied in the form of a software product.

[0081] Finally, it should be noted that the Kama alloy strain gauge, heart rate detection method and device disclosed in the embodiments of the present invention are only preferred embodiments of the present invention, which are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A heart rate detection method based on Kama alloy strain gauge, characterized in that: The Kama alloy strain gauge comprises at least a first layer, a second layer and a third layer, wherein the first layer comprises a Kama alloy layer, the second layer comprises a metal strain gauge layer, and the third layer comprises a piezoelectric material layer. The method comprises: Obtaining a second output signal of the second layer of the kama alloy strain gauge attached to the skin of the organism, and determining whether a target signal exists in the second output signal, the target signal including a signal generated by deformation of the second layer caused by non-heart rate-varying movement of the skin of the organism; If it is determined that the second output signal contains a target signal, determining a third input signal for deforming the third layer according to the target signal; inputting the third input signal to the third layer, so that the third layer drives the second layer and the first layer to undergo corresponding deformation; A first output signal of the first layer is acquired, and heart rate information of the biological body is obtained according to the first output signal.

2. The heart rate detection method based on the Kama alloy strain gauge according to claim 1 is characterized in that: The strain sensitivity coefficient of the second layer is lower than that of the first layer, and the strain sensitivity coefficient indicates the degree of resistance change of the strain gauge as the strain gauge is deformed.

3. The heart rate detection method based on the Kama alloy strain gauge according to claim 1, characterized in that: The second output signal is a voltage signal or a current signal, and determining whether the target signal exists in the second output signal includes: determining, based on the second output signal, a change relationship between the second output signal and time, wherein the change relationship is used to represent a change of the second output signal over time; It is determined whether the change relationship corresponds to a preset change relationship. If it is determined that the change relationship corresponds to the preset change relationship, it is determined that a target signal exists in the second output signal.

4. The heart rate detection method based on the Kama alloy strain gauge according to claim 3 is characterized in that: The determining whether the change relationship corresponds to a preset change relationship includes: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, wherein the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; Inputting the second output signal-time variation curve into a pre-trained target signal analysis model, wherein the target signal analysis model is obtained by training multiple sets of signal-time variation curves and is used to analyze whether the input signal-time variation curve conforms to a preset target linear shape; If the target signal analysis model analyzes that the second output signal-time variation curve conforms to the target linear shape, it is determined that the variation relationship corresponds to a preset variation relationship.

5. The heart rate detection method based on the Kama alloy strain gauge according to claim 3 is characterized in that: The determining that the change relationship corresponds to the preset change relationship includes: determining that the change relationship indicates that the voltage value of the second output signal is continuously greater than or equal to a preset voltage threshold value within a preset time length, or that the current value of the second output signal is continuously greater than or equal to a preset current threshold value within a preset time length, then determining that the change relationship corresponds to the preset change relationship; And, determining a third input signal for deforming the third layer according to the target signal includes: determining a voltage value or a current value of the second output signal as a target signal; A third input signal for causing the third layer to deform is determined based on the voltage value or current value corresponding to the target signal. The third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

6. The heart rate detection method based on the Kama alloy strain gauge according to claim 3 is characterized in that: The determining that the change relationship corresponds to the preset change relationship includes: According to the variation relationship between the second output signal and time, a second output signal-time variation curve is obtained by fitting, wherein the second output signal-time variation curve is used to fit the corresponding relationship between the second output signal and time; If it is determined that a preset corresponding relationship exists between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer, then it is determined that the variation relationship corresponds to the preset variation relationship; And, determining a third input signal for deforming the third layer according to the target signal includes: determining the second output signal-time variation curve as a target signal; The frequency of the third input signal used to cause the third layer to deform is determined according to the frequency corresponding to the target signal, and the amplitude of the third input signal used to cause the third layer to deform is determined according to the amplitude corresponding to the target signal; the third input signal is used to cause the third layer to drive the first layer to undergo corresponding deformation, thereby offsetting the deformation of the first layer caused by non-heart rate change movement of the biological skin.

7. The heart rate detection method based on the Kama alloy strain gauge according to claim 6 is characterized in that: The determining that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer includes: determining a frequency of the second output signal-time variation curve as a second frequency, and determining a frequency of the first output signal of the first layer as a first frequency; If it is determined that the first frequency is an integer multiple of the second frequency, or the second frequency is an integer multiple of the first frequency, then it is determined that there is a preset corresponding relationship between the frequency of the second output signal-time variation curve and the frequency of the first output signal of the first layer.

8. A Kama alloy strain gauge, characterized in that: The Kama alloy strain gauge is attached to the skin of a living body when in use, and the Kama alloy strain gauge includes: A second layer comprising a metal strain gauge layer; the second layer is used to obtain a second output signal; The third layer includes a piezoelectric material layer; the third layer is used to obtain a third input signal and drive the second layer and the first layer to undergo corresponding deformation according to the third input signal; A first layer includes a Kama alloy layer; the first layer is used to obtain a first output signal, and the first output signal is used to obtain heart rate information of the organism; Among them, the third input signal is a signal determined based on the target signal when it is determined that there is a target signal in the second output signal, and the target signal includes a signal generated by the deformation of the second layer caused by non-heart rate change movement of the biological skin.

9. The Kama alloy strain gauge according to claim 8, characterized in that: The strain sensitivity coefficient of the second layer is lower than that of the first layer, and the strain sensitivity coefficient indicates the degree of resistance change of the strain gauge as the strain gauge is deformed.

10. A heart rate detection device based on a Kama alloy strain gauge, characterized in that: The Kama alloy strain gauge comprises at least a first layer, a second layer and a third layer, wherein the first layer comprises a Kama alloy layer, the second layer comprises a metal strain gauge layer, and the third layer comprises a piezoelectric material layer. The device comprises: a second acquisition module, configured to acquire a second output signal of the second layer of the kama alloy strain gauge attached to the skin of the organism, and determine whether a target signal exists in the second output signal, wherein the target signal includes a signal generated by deformation of the second layer caused by non-heart rate-varying movement of the skin of the organism; a signal analysis module configured to, when determining that a target signal exists in the second output signal, determine a third input signal for causing the third layer to deform according to the target signal; a signal output module, configured to input the third input signal to the third layer, so that the third layer drives the second layer and the first layer to undergo corresponding deformation; The first acquisition module is used to acquire the first output signal of the first layer and obtain the heart rate information of the organism according to the first output signal.

Images