Cardiac shock signal collecting and sensing device and seat with cardiac shock signal collecting and sensing device

Abstract

The invention discloses a ballistocardiogram signal collecting and sensing device and a seat with the same, and relates to the technical field of human body vital sign monitoring. Comprising a first dielectric layer, a pressure sensitive layer, a second dielectric layer and a control host, the pressure sensitive layer is fixedly installed between the first dielectric layer and the second dielectric layer, and the pressure sensitive layer is attached to the first dielectric layer and the second dielectric layer; the area of the cross section of the first dielectric layer is larger than that of the cross section of the pressure sensitive layer, and the first dielectric layer is always spaced from the second dielectric layer when bearing the pressure within the weight range of the human body. The device has the beneficial effect that weak vibration caused by cardiac pulsation can be accurately captured.

Description

Technical Field

[0001] The present invention relates to the technical field of human vital sign monitoring, and particularly to a ballistocardiogram signal acquisition and sensing device and a seat having the same. Background Art

[0002] In exploring innovative paths in the future field of home health monitoring, non-invasive vital sign monitoring technology has gradually emerged. This cutting-edge technology cleverly integrates high-precision sensors into daily household items, enabling continuous and implicit collection of key health data of the human body without disturbing the normal life of users, and building a detailed and personalized health information database for each family member.

[0003] Among many non-invasive monitoring technologies, ballistocardiogram (BCG) technology stands out with its unique advantages. It relies on advanced vibration sensing sensor technology to accurately capture the subtle periodic fluctuations of the chest caused by cardiac pumping and respiratory movements, and then accurately analyzes key physiological parameters such as heart rate and respiratory rate, providing timely and accurate feedback on the user's health status.

[0004] However, BCG sensors on the current market generally face a challenge: since human activities such as cardiac pumping and breathing are relatively weak and it is difficult to accurately capture relevant physiological parameters, when collecting these parameters, the human body needs to closely fit the effective sensing area to accurately collect relevant parameters. However, as household items, people will not deliberately adjust their sitting or lying postures to adapt to these products in daily life, which will affect the fluency of the user experience and make it difficult to popularize such household items.

[0005] Therefore, there is an urgent need to provide a sensing device that can accurately capture physiological parameters of weak human activities. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a ballistocardiogram signal acquisition and sensing device and a seat having the same, which can accurately capture parameters of weak physiological activities of the human body.

[0007] The present invention provides a ballistocardiogram signal acquisition and sensing device, including a first dielectric layer, a pressure-sensitive layer, a second dielectric layer, and a control host. The pressure-sensitive layer is fixedly installed between the first dielectric layer and the second dielectric layer, and the pressure-sensitive layer is adhered to the first dielectric layer and the second dielectric layer. The cross-sectional area of the first dielectric layer is larger than the cross-sectional area of the pressure-sensitive layer, and the first dielectric layer always maintains a gap with the second dielectric layer when bearing pressure within the range of the human body weight.

[0008] Optionally, the first dielectric layer is made of a rigid material.

[0009] Optionally, the second dielectric layer is made of a rigid material, and the cross-sectional area of the second dielectric layer is larger than that of the pressure-sensitive layer.

[0010] Optionally, it further includes a connecting member made of a rigid material; the connecting member connects the first dielectric layer and the second dielectric layer together, and the first dielectric layer and the second dielectric layer are kept relatively fixed in the transverse direction.

[0011] Optionally, at least three pairs of coaxial first connection holes and second connection holes are respectively formed in the first dielectric layer and the second dielectric layer, and the connecting member passes through the first connection holes and the second connection holes of the first dielectric layer and the second dielectric layer to fixedly connect the first dielectric layer and the second dielectric layer together.

[0012] Optionally, on the surfaces of the first dielectric layer and the second dielectric layer away from the pressure-sensitive layer, a circle of grooves is respectively formed along the perimeters of the first connection holes and the second connection holes. The connecting member includes a connecting portion and two abutting portions respectively located at opposite ends of the connecting portion. The connecting portion passes through the first connection holes and the second connection holes, and the two abutting portions at both ends of the connecting portion are respectively located in the grooves of the first dielectric layer and the second dielectric layer, and the abutting portions limit the connecting portion in the transverse direction.

[0013] Optionally, the length of the connecting portion of the connecting member is greater than the distance between the bottoms of the grooves of the first dielectric layer and the second dielectric layer and not greater than 1 mm, and the height of the connecting portion is less than the height of the groove and at least 1 mm less.

[0014] Optionally, it further includes an acceleration sensor, which is signal-connected to the control host, and the acceleration sensor is used to sense the pressure received by the first dielectric layer.

[0015] Optionally, the control host includes a wake-up module, which is signal-connected to the acceleration sensor. When the acceleration sensor senses a pressure exceeding a set threshold, the wake-up module wakes up the control host.

[0016] Optionally, the control host includes a direction recognition module, which is signal-connected to the pressure-sensitive layer, and the direction recognition module is used to recognize the direction of the pressure sensed by the acceleration sensor.

[0017] Optionally, the control host includes a filtering module, which is signal-connected to the pressure-sensitive layer. When the acceleration sensor senses a pressure exceeding a set threshold on the pressure-sensitive layer, this part of the pressure is input as a noise source, and the filtering module filters the noise source.

[0018] The present invention also provides a seat, which includes the heart impact signal acquisition and sensing device as described above, and the heart impact signal acquisition and sensing device is arranged below the bearing surface of the seat for bearing the human body.

[0019] The heart impact signal acquisition and sensing device provided by the present invention and the seat having the same fix the pressure-sensitive layer through the first dielectric layer and the second dielectric layer. When a human body sits on the first dielectric layer, the pressure-sensitive layer captures the weak physiological activity parameters of the human body. The first dielectric layer is made of a rigid material, which can effectively reduce the loss of the slight vibration caused by the weak physiological activities of the human body on the first dielectric layer, and transmit the vibration information through the pressure-sensitive layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a display diagram of an existing BCG physiological signal acquisition system and work process.

[0022] Figure 2 It is a module schematic diagram of a heart impact signal acquisition and sensing device of the present invention.

[0023] Figure 3 It is a force analysis diagram of a BCG physiological signal acquisition system.

[0024] Figure 4 It is a partial structure schematic diagram of a heart impact signal acquisition and sensing device of the present invention.

[0025] Figure 5 It is a force analysis diagram of a BCG physiological signal acquisition system.

[0026] Figure 6 It is a module schematic diagram of a heart impact signal acquisition and sensing device of the present invention.

[0027] Figure 7 It is a direction identification schematic diagram of an acceleration sensor in a heart impact signal acquisition and sensing device of the present invention.

[0028] Figure 8 It is the schematic diagram of the principle of adaptive noise reduction.

[0029] Figure 9 It is the schematic structural diagram of a cardiogenic shock signal acquisition and sensing device of the present invention.

[0030] Figure 10 It is the schematic structural diagram of an embodiment of a seat of the present invention.

[0031] Figure 11 It is the schematic structural diagram of another embodiment of a seat of the present invention.

[0032] In the figure:

[0033] Round stool 1, first conduction medium layer 2, sensitive material layer 3, second conduction medium layer 4, host 5;

[0034] First medium layer 10, first connection hole 11, groove 12, pressure-sensitive layer 20, first screw 21, second medium layer 30, second connection hole 31, control host 40, battery 41, upper shell 42, lower shell 43, control circuit system 44, piezoresistive sensor 50, connecting piece 60, connecting portion 61, abutting portion 62, protection strip 70;

[0035] First flexible material medium layer 100, intelligent seat 200, second flexible material medium layer 300;

[0036] First seat cushion layer 101, second seat cushion layer 102, circular frame 103, cardiogenic shock signal acquisition and sensing device 104, support base 105, cushion layer 106;

[0037] Seat bracket 201, support plate 202, square frame 204, first sponge layer 206, second sponge layer 205, outer surrounding sponge 207. Detailed implementation manners

[0038] Next, specific embodiments of the present invention will be described in detail in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the description of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] Unless otherwise clearly specified and defined, terms such as "set", "install", "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific situations.

[0040] The orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is customarily placed during use. It is only for the convenience of description and to simplify the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0041] Terms such as "first", "second", "third", etc. are only used to distinguish elements with similar attributes, rather than indicating or implying relative importance or a specific order.

[0042] The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.

[0043] As Figure 1 shown, Figure 1 It is a display of an existing BCG physiological signal acquisition system and workflow. The system includes a round stool 1 and a BCG sensor located inside the round stool 1. The BCG sensor includes a first conductive medium layer 2, a sensitive material layer 3, a second conductive medium layer 4, and a host 5 that are distributed in sequence from top to bottom. The first conductive medium layer 2 and the second conductive medium layer 4 are made of flexible materials. The cardiac shock signal generated by the heartbeat acts on the round stool 1 and is conducted through the seat cushion of the round stool 1 to the BCG sensor hidden inside the round stool 1. The signal first passes through the first conductive medium layer 2 and is captured by the sensitive material layer 3. The second conductive medium layer 4 mainly serves to support the sensitive material layer 3 to ensure that the sensitive material layer 3 can reliably sense the vibration signal. Subsequently, the host 5 converts the change in the electrical characteristics of the sensitive material layer 3 into a voltage signal to generate a ballistocardiogram (BCG). By analyzing the ballistocardiogram, key physiological parameters such as heart rate, respiratory rate, and blood pressure are further calculated.

[0044] As Figure 2As shown in the figure, the ballistocardiogram (BCG) signal acquisition and sensing device provided in this embodiment includes a first dielectric layer 10, a pressure-sensitive layer 20, a second dielectric layer 30, a control host 40, and a piezoresistive sensor 50. The pressure-sensitive layer 20 is fixedly installed between the first dielectric layer 10 and the second dielectric layer 30, and the pressure-sensitive layer 20 is in contact with the first dielectric layer 10 and the second dielectric layer 30. The first dielectric layer 10 and the second dielectric layer 30 play a fixing role for the pressure-sensitive layer 20, and the pressure-sensitive layer 20 is used to detect the minute mechanical movement and pressure change of the human body. The pressure-sensitive layer 20 can be composed of piezoelectric materials, resistive materials, capacitive materials, or other materials with pressure response characteristics, or it can be a pressure-sensitive structure. The pressure-sensitive layer 20 can convert the minute mechanical pressure signal of the human body into a measurable electrical signal. When the weak vibration generated by the human heart beat acts on the first dielectric layer 10, the control host 40 collects the electrical signal converted from the mechanical vibration signal sensed by the pressure-sensitive layer 20 and generates a ballistocardiogram according to the electrical signal. The cross-sectional area of the first dielectric layer 10 is larger than the cross-sectional area of the pressure-sensitive layer 20, and the first dielectric layer 10 always maintains a gap with the second dielectric layer 30 within the pressure range of bearing the human body weight. In this way, when the human body weight presses on the first dielectric layer, the minute vibration of the human heart can be transmitted to the pressure-sensitive layer without loss or with less loss, avoiding the direct transmission of the human body vibration from the first dielectric layer to the second dielectric layer due to the contact between the first dielectric layer and the second dielectric layer, resulting in inaccurate minute vibration signals of the human heart collected by the pressure-sensitive layer.

[0045] BCG technology mainly measures the force acting on the sensor due to the heart beat of the human body in real time, draws a ballistocardiogram, and thus obtains various physiological parameters. Therefore, in the design of the mechanical conduction path, it is necessary to ensure that the force can be effectively transmitted to the sensor. Therefore, the force condition of the sensor is analyzed. According to Hooke's law, in elasticity, it is used to describe the linear relationship between stress and strain in solid materials when they are subjected to external forces. For one-dimensional cases (such as tension or compression), Hooke's law can be expressed as Equation (1):

[0046] σ = Eε (1)

[0047] In the formula, σ is the stress (the force per unit area on the first dielectric layer 10), E is the elastic modulus (also known as Young's modulus), and ε is the strain (the relative change in length).

[0048] According to Hooke's law, under the same force condition, the larger the elastic modulus of the material, the smaller the strain generated. Figure 3 The force analysis under different sensing schemes is shown. Figure 3(a) shows the force-bearing situation of the medium made of rigid material in this embodiment. Since the elastic modulus of the rigid material is extremely large, it hardly deforms. According to Newton's third law, the pressure borne by the pressure-sensitive layer 20 is equal to the force applied to the first medium layer 10, and the force transmission does not attenuate. Figure 3 (b) shows the force-bearing situation of the medium made of flexible material. The flexible material deforms significantly after being stressed, and the first flexible material medium layer 100 contacts the second flexible material medium layer 300. On the premise that the pressure is uniform on each contact surface, the pressure borne by the pressure-sensitive layer 20 can be expressed as where S0 is the contact area of the pressure-sensitive layer 20, and S is the contact area between the first flexible material medium layer 100 and the human body. Since the contact area of the pressure-sensitive layer 20 is usually small, compared with the rigid medium, the force received by the pressure-sensitive layer 20 under the flexible medium is greatly reduced. Therefore, the rigid structure can ensure that only the pressure-sensitive layer 20 contacts the first medium layer 10 on the section where the pressure-sensitive layer 20 is located, so as to receive the strongest weak vibration force of the human body. The first medium layer 10 made of rigid material can sensitively capture the weak vibration generated by the human body.

[0049] Therefore, in this embodiment, the first medium layer 10 is preferably made of rigid material, which can sensitively capture the weak vibration generated by the human body and can minimize the attenuation of the weak vibration generated by the human body during transmission. The rigid material refers to the material with extremely small or no deformation under the action of force. Specifically in the application field of this application, the rigid material referred to in this application is the material that does not deform when bearing the pressure within the normal human body weight range.

[0050] The vibration generated by the heart beat occurs simultaneously in the vertical and horizontal directions. The vibration pressure collected by the pressure-sensitive layer 20 is mainly in the vertical direction. In order to facilitate the better transmission of the vibration generated by the heart beat to the pressure-sensitive layer 20 in the vertical direction of the first medium layer 10, as Figure 4 shown, the heart impact signal acquisition and sensing device provided in this embodiment further includes a connecting member 60, and the connecting member 60 is made of rigid material. The connecting member 60 connects the first medium layer 10 and the second medium layer 30 together, and the first medium layer 10 and the second medium layer 30 are relatively fixed in the horizontal direction.

[0051] Specifically, at least three pairs of coaxial first connection holes 11 and second connection holes 31 are respectively formed on the first medium layer 10 and the second medium layer 30. At least three pairs of coaxial first connection holes 11 and second connection holes 31 are respectively distributed in a triangular or rectangular shape. The connecting member 60 passes through the first connection holes 11 and the second connection holes 31 of the first medium layer 10 and the second medium layer 30, so as to fixedly connect the first medium layer 10 and the second medium layer 30 together.

[0052] Furthermore, on the surfaces of the first dielectric layer 10 and the second dielectric layer 30 away from the pressure-sensitive layer 20, a ring of grooves 12 is respectively provided along the perimeters of the first connection hole 11 and the second connection hole 31. The connecting member 60 includes a connecting portion 61 and two abutting portions 62 respectively located at opposite ends of the connecting portion 61. The connecting portion 61 passes through the first connection hole 11 and the second connection hole 31, and the two abutting portions 62 at both ends of the connecting portion 61 are respectively located in the grooves 12 of the first dielectric layer 10 and the second dielectric layer 30. The abutting portion 62 limits the connecting portion 61 in the transverse direction, that is, the abutting portion 62 abuts against the side wall of the groove 12 in the groove 12, so that the abutting portion 62 cannot move laterally in the groove 12, thereby fixing the position of the connecting portion 61. Through physical constraints, the pressure of the weak vibration generated by the heartbeat mainly acts in the direction perpendicular to the pressure-sensitive layer 20, so that the vibration has only the vertical degree of freedom (the same as the main direction of the heart vibration). Doing so can not only reduce the signal interference in the non-vertical direction, but also ensure that the pressure-sensitive layer 20 captures and amplifies the vertical vibration signals generated by physiological activities such as heartbeats more intensively and efficiently, thereby improving the quality and signal-to-noise ratio of the signals and providing a more accurate and reliable data basis for subsequent signal processing and analysis.

[0053] Furthermore, the length of the connecting portion 61 of the connecting member 60 is greater than the distance between the bottoms of the grooves 12 of the first dielectric layer 10 and the second dielectric layer 30 and not greater than 1 mm, and the height of the connecting portion 61 is less than the height of the groove 12 and at least 1 mm less. This enables the connecting member 60 to move appropriately in the vertical direction between the first dielectric layer 10 and the second dielectric layer 30 and the abutting portions 62 at both ends of the connecting portion 61 will not move out of the groove 12, making the capture of weak vibrations by the pressure-sensitive layer 20 more sensitive in the vertical direction and ensuring the stable operation and effective vibration of the system.

[0054] Specifically, the connecting portion 61 can be a screw, and the abutting portion 62 can be a nut. A threaded hole is provided in the nut, and the screw is threadedly connected to the nut. The two ends of the nut respectively abut against the side walls of the groove 12 to limit the screw in the transverse direction. The screw also has a certain stiffness and will not deform during vibration, avoiding the attenuation of the pressure generated by weak vibrations during transmission. The connecting portion 61 can also be a columnar structure made of a rigid material, and metal discs having the same cross-section as the groove 12 are respectively fixedly connected to both ends thereof. The metal discs are located in the groove 12, so that the connecting portion 61 can only displace appropriately in the vertical direction and cannot displace laterally.

[0055] The above analysis of the vertical vibration generated by the heartbeat also produces lateral vibrations during the heartbeat. Such lateral vibrations are at risk of attenuation during transmission, and they are affected by the path length and the properties of the medium during transmission, manifested as attenuation of the vibration signal and energy loss. The degree of attenuation is usually related to the length of the transmission path, the damping characteristics of the medium, and the signal frequency. The attenuation of the vibration signal is usually described by the exponential attenuation formula:

[0056] A(x) = A0e -αx (2)

[0057] In the formula, A(x) is the amplitude of the vibration signal at the transmission distance x; A0 is the initial amplitude of the vibration signal; α is the attenuation coefficient of the medium, which depends on the properties of the medium (including the density, elasticity, damping coefficient, etc. of the material); x is the length of the transmission path, and e is the Euler number.

[0058] The attenuation coefficient α is usually related to the damping coefficient of the medium, the frequency f, and the physical properties of the medium. In some ideal cases, the attenuation coefficient can be expressed as:

[0059]

[0060] In the formula, f is the frequency of the vibration signal; v is the propagation speed of the wave in the medium; Q is the quality factor of the medium, which reflects the damping characteristics of the medium. The smaller the Q value, the faster the attenuation. The quality factors of common materials are shown in Table (1):

[0061] Material Quality factor Q EVA (ethylene-vinyl acetate copolymer) 5-50 Sponge 5-30 Fabric 1-50 Wood board 50-500 Acrylic board (PMMA) 500-1000 ABS board (acrylonitrile-butadiene-styrene copolymer) 50-200

[0062] Table (1)

[0063] These values are for reference ranges, and the actual Q value will be affected by factors such as material processing technology, temperature, and frequency. The specific quality factor usually needs to be determined through experiments.

[0064] For the conduction of vibration signals, the length of the conduction path and the quality factor are the two key factors determining the attenuation of the vibration signal amplitude. Therefore, optimization can be carried out from the selection of the conduction path and the material of the first dielectric layer 10: First, try to shorten the conduction path of the vibration signal, reduce the attenuation of the signal during propagation, and ensure the maximization of the signal intensity before transmission to the sensor. Second, preferably select materials with high quality factors, reduce energy loss, and improve the efficiency of signal conduction. Select materials that can effectively amplify or maintain the signal amplitude to maximize the detectability of the vibration signal.

[0065] Traditional BCG sensor designs typically embed a sensitive material layer 3, such as a PVDF piezoelectric film, an optical fiber sensor, or a piezoelectric helically wound coaxial cable, between a first conductive medium layer 2 (a flexible material such as cloth or sponge) and a second conductive medium layer 2. However, such designs have significant limitations: the sensitive material layer 3 often cannot fully cover the contact surface of the first medium conductive layer 2, as shown in Figure 5 (b), resulting in a non-direct contact conduction space between the vibration source and the sensitive material layer 3, and due to the soft material properties of the first conductive medium layer 2, the first conductive medium layer 2 and the second conductive medium layer 3 will partially adhere, thereby causing signal attenuation. Specifically, as the conduction distance increases, the amplitude of the vibration signal will significantly decrease, and the lower the quality factor of the conductive medium, the faster the attenuation rate, as shown in Figure 5 (c), which poses a challenge to the accurate acquisition of BCG signals.

[0066] Therefore, the core of the ballistocardiogram signal acquisition sensing device proposed in this embodiment lies in the selection of the material for the first medium layer 10. This embodiment abandons traditional flexible materials and instead uses rigid materials as the first medium layer 10, including but not limited to high-strength and high-stability materials such as wooden boards, acrylic boards, and ABS boards. As can be seen from Table (1), the rigid material of the first medium layer 10 in this embodiment should be a rigid material with a quality factor Q greater than 50. The rigid material can ensure that when the sensor surface is vibrated by the human sitting posture, the vibration wave can be transmitted more directly and efficiently to the area where the pressure sensitive layer 20 is located. No matter where the human body sits above the first medium layer 10, the vibration signal can be transmitted to the pressure sensitive layer 20 efficiently and with low attenuation. Compared with traditional flexible materials, rigid materials have a stronger quality factor, effectively reducing the attenuation of vibration signals during conduction, thereby improving the acquisition quality and efficiency of the pressure sensitive layer 20 for vibration signals.

[0067] In summary, this embodiment realizes the optimization of the vibration signal conduction path by using a rigid material as the constituent material of the first medium layer 10, providing strong support for the accurate and efficient acquisition of BCG signals.

[0068] In the current BCG design, both the first medium layer 10 and the second medium layer 30 are made of flexible materials. In order to further enhance the capture accuracy of the weak vibrations of the human heart beat, the second medium layer 30 in this embodiment is made of a rigid material.

[0069] In a damped vibration system, the solution of the dynamic equation gives the relationship between the amplitude x and time t, which usually involves the effects of the damping coefficient c, mass m, and spring constant k. However, directly solving for the explicit relationship between the amplitude x and these parameters can be complex because the amplitude x is typically a function of time and involves exponential decay and trigonometric functions (for underdamped and critically damped cases) or only exponential decay (for overdamped cases).

[0070] For a one-dimensional damped vibration system, the dynamic equation is:[[]]

[0071]

[0072] where x is the amplitude as a function of time; m is the mass of the system; c is the damping coefficient; k is the system stiffness; F0 is the amplitude of the external force; ω is the angular frequency of the external force; and t is time.

[0073] When solving this equation, a steady-state solution and a transient solution are obtained. As time progresses, the transient solution decays, and the remaining steady-state solution is usually expressed as:

[0074] x(t) = A cos(ωt - φ) (5)

[0075] where A is the steady-state amplitude of the vibration, which is affected by the system parameters and the external force frequency; φ is the phase difference, ω is the angular frequency of the external force; and t is time.

[0076] The steady-state amplitude A can be expressed as:

[0077]

[0078] where ω0 is the natural frequency of the system; ζ is the damping ratio, m is the mass of the system, k is the system stiffness, c is the damping coefficient, F0 is the amplitude of the external force, and ω is the angular frequency of the external force.

[0079] Substituting ω0 and ζ into Equation (6) gives:

[0080]

[0081] where: F0 is the amplitude of the external force, m is the mass of the system, ω is the angular frequency of the external force, c is the damping coefficient, and k is the system stiffness.

[0082] As can be seen from Equation (7), for a vibration system, the damping coefficient c is a key property that determines the amplitude A of the system. The smaller the damping coefficient c, the larger the amplitude A(t). In the design of a BCG sensor, the first dielectric layer 10, the second dielectric layer 30, and the pressure-sensitive layer 20 together form the core vibration signal acquisition unit. This unit is not only responsible for receiving the weak vibration of the human heart beat but also resonates with this vibration. Therefore, selecting a material with a smaller damping coefficient is crucial for the effective acquisition of BCG signals. Based on this consideration, in this design, the second dielectric is preferably made of a rigid material to optimize the signal conduction and acquisition performance. Moreover, the cross-sectional area of the second dielectric layer 30 is larger than that of the pressure-sensitive layer 20, which can prevent the pressure-sensitive layer 20 from contacting the outside. When the pressure-sensitive layer receives the minute vibration of the human body transmitted by the first dielectric layer, if the pressure-sensitive layer contacts the outside at the second dielectric layer and the external object is a flexible object, it will cause the loss of vibration signals, resulting in inaccurate detection of the minute vibration of the human body by the pressure-sensitive layer.

[0083] Table (2) shows the damping coefficients of some materials:

[0084] Material Damping coefficient c EVA (ethylene-vinyl acetate copolymer) 0.05-0.25 Sponge 0.1-0.4 Fabric 0.2-1.0 Wood board 0.01-0.05 Acrylic board (PMMA) 0.001-0.02 ABS board (acrylonitrile-butadiene-styrene copolymer) 0.005-0.02

[0085] Table (2)

[0086] As can be seen from Table (2), when the second dielectric layer 30 is made of a rigid material and is suitable for human detection, the damping coefficient of the rigid material should be less than 0.01, such as a wooden board, an acrylic board, an ABS board, etc.

[0087] Furthermore, as Figure 6 shown, the ballistocardiogram signal acquisition and sensing device provided in this embodiment further includes an acceleration sensor. The acceleration sensor is signal-connected to the control host 40, and the acceleration sensor is used to sense the pressure received by the first dielectric layer 10.

[0088] Among them, the control host 40 includes a wake-up module. The wake-up module is signal-connected to the acceleration sensor. When the acceleration sensor senses a pressure exceeding a set threshold, the wake-up module wakes up the control host 40. When no pressure is felt acting on the first dielectric layer 10, the control host 40 can be in a sleep state to save power. When a person sits above the first dielectric layer 10, the weight of the person acts on the pressure-sensitive layer 20 in a short time. After the acceleration sensor recognizes this signal, it wakes up the control host 40 through the wake-up module to capture and convert the weak vibration of the human heart beat. Moreover, a piezoresistive sensor 50 can be further set as a wake-up mechanism. The piezoresistive sensor 50 and the acceleration sensor together perform the wake-up function, making the device wake up more sensitively.

[0089] Furthermore, as Figure 6 andFigure 7 As shown, the control host 40 further includes a direction recognition module. The direction recognition module is signal-connected to the pressure-sensitive layer 20 and is used to recognize the pressure direction sensed by the acceleration sensor. The direction recognition module is used to recognize the direction in which the pressure acts on the first medium layer 10, such as horizontal, vertical, and vertical. According to the recognized pressure direction, it is judged whether the placement orientation of the device is correct. For example, if the main direction to be measured is vertical, and if the recognized pressure direction is horizontal or vertical, it means that the placement orientation of the cardiac impact signal acquisition sensing device is incorrect. At this time, an alarm can be made to prompt the user to adjust the placement orientation of the device, so as to ensure the accuracy and effectiveness of data acquisition.

[0090] In addition, as Figure 6 and Figure 8 shown, the control host 40 further includes a filtering module. The filtering module is signal-connected to the pressure-sensitive layer 20. When the acceleration sensor senses a pressure exceeding the set threshold on the pressure-sensitive layer 20, this part of the pressure is input as a noise source, and the filtering module filters the noise source. When a person sits above the first medium layer 10, there may be limb movements such as leg shaking, and these limb movements will cause vibrations on the first medium layer 10, which will affect the collection of weak vibration signals of the cardiac pulsation. Therefore, the filtering module filters these pressure sources above the threshold to accurately collect the weak vibration signals brought by the cardiac pulsation and improve the accuracy of signal collection.

[0091] As Figure 9 shown, Figure 9 This is a specific embodiment of the cardiac impact signal acquisition sensing device provided in this embodiment, which includes a piezoresistive sensor 50, two protection strips 70, a first screw 21, a connecting member 60, a first medium layer 10, a pressure-sensitive layer 20, a second medium layer 30, and a control host 40.

[0092] Among them, the piezoresistive sensor 50 is arranged on the upper surface of the first medium layer 10, and the two protection strips 70 are respectively arranged on both sides of the piezoresistive sensor 50. The protection strips 70 are made of high-elastic and wear-resistant EVA (ethylene-vinyl acetate copolymer) films. The height of the protection strips 70 is slightly higher than that of the piezoresistive sensor 50, forming a physical barrier for the piezoresistive sensor 50 on both sides. When a person sits on the first medium layer 10, because the human body is relatively soft, it will not be unable to contact the piezoresistive sensor 50 under the block of the protection strips 70. Setting the protection strips 70 can prevent the piezoresistive sensor 50 from being damaged by accidental impact or excessive pressure, and ensure the long-term stable operation of the piezoresistive sensor 50.

[0093] Among them, the first medium layer 10 is an acrylic board, and the acrylic board has strong stiffness, can effectively conduct vibrations, and has excellent transparency, weather resistance, and processing performance, providing a solid and beautiful base for the overall module.

[0094] Among them, the pressure-sensitive layer 20 is a piezoelectric helically wound coaxial cable, which not only significantly reduces the cost, but also greatly improves the flexibility and adaptability of vibration monitoring. By finely adjusting the winding shape and coverage range of the cable under the first dielectric layer 10, the precise perception of vibrations in different regions of the first dielectric layer 10 can be easily achieved, meeting the requirements of diverse application scenarios. The cable is firmly attached to the second dielectric layer 30 by bonding or the first screw 21 to ensure stable and reliable signal transmission. In addition, the piezoelectric helically wound coaxial cable is not the only option, and other piezoelectric sensitive materials can also be used. To enhance the support stiffness, materials with better stiffness such as EVA are used to prevent the direct contact between the first dielectric layer 10 and the second dielectric layer 30. Other piezoelectric sensitive material layers can be fiber optic sensors, PVDF piezoelectric films, vibration sensors such as airbags, etc.

[0095] Among them, regarding the second dielectric layer 30, in this embodiment, it is selected as a wooden board, and the second dielectric layer 30 can also be selected from other materials according to the requirements of the actual usage scenario. It should be noted that according to the changes in the specific application scenario, the piezoresistive sensor 50 can also be flexibly adjusted to be installed on the lower surface of the second dielectric layer 30 to optimize the detection effect or meet the space layout requirements.

[0096] First connection holes 11 and second connection holes 31 are respectively formed on the first dielectric layer 10 and the second dielectric layer 30. A circle of grooves 12 is respectively formed on the upper surface of the first dielectric layer 10 and the lower surface of the second dielectric layer 30 along the peripheries of the first connection holes 11 and the second connection holes 31. The connecting member 60 passes through the first connection holes 11 and the second connection holes 31 to fix the first dielectric layer 10 and the second dielectric layer 30 together. Moreover, abutting blocks made of metal are respectively fixedly connected to both ends of the connecting member 60. The abutting blocks are located in the grooves 12 to limit the connecting member 60 in the radial direction of the first connection holes 11, so that the connecting member 60 can only move appropriately in the axial direction of the first connection holes 11. The abutting blocks can be structures with the same cross-sectional shape as the grooves 12, or the length of the abutting blocks can be the same as the length of the grooves 12.

[0097] Among them, the control host 40 is jointly composed of a flame-retardant and high-strength host shell, a control circuit system 44, and a battery 41. The host shell includes an upper shell 42 and a lower shell 43. The upper shell 42 and the lower shell 43 enclose to form a shell with a cavity inside. The battery 41 and the control circuit system 44 are located inside the cavity. In this embodiment, the whole device is encapsulated in a shape with the commonly used materials of furniture such as wooden boards and acrylic boards as the shell, and it also has strong anti-seismic and drop protection capabilities, making it more convenient to be combined with traditional furniture. This highly integrated structural design not only improves the overall performance and reliability of the module, but also simplifies the installation and maintenance processes, providing a more convenient user experience.

[0098] In summary, the ballistocardiogram (BCG) signal acquisition and sensing device provided in this embodiment has the following advantages:

[0099] 1. The first dielectric layer 10 is made of a rigid material, which is more likely to transmit vibration signals to the pressure-sensitive layer 20 below the first dielectric layer 10.

[0100] 2. The second dielectric layer 30 is made of a rigid material. On the one hand, it provides stable structural support and promotes the generation of vibration signals. On the other hand, it also reduces the overall equivalent damping coefficient and increases the mass, enhancing the amplitude, that is, enhancing the BCG signal.

[0101] 3. The vibration direction is restricted by the connecting member 60 to ensure that the information related to body vibration is maximally amplified.

[0102] 4. The placement direction and state of the device can be identified by the acceleration sensor.

[0103] 5. Adaptive noise reduction can be performed through acceleration.

[0104] 6. The overall rigid design is more likely to be integrated with the production process of traditional furniture.

[0105] This embodiment also provides a seat, including the BCG signal acquisition and sensing device as described above. The BCG signal acquisition and sensing device is disposed below the bearing surface of the seat for bearing the human body. When a person sits on the seat, the human weight presses on the first dielectric layer 10 of the BCG signal acquisition and sensing device.

[0106] For a specific embodiment of the seat, as Figure 10 shown, this embodiment provides an intelligent round stool, which sequentially includes a first seat cushion layer 101, a second seat cushion layer 102, a circular frame 103, a BCG signal acquisition and sensing device 104, a support base 105, and a cushion layer 106 from top to bottom. The circular frame 103 is fixedly installed on the support base 105. The middle of the circular frame 103 is hollow. The BCG signal acquisition and sensing device 104 is disposed in the circular frame 103, and the first dielectric layer 10 of the BCG signal acquisition and sensing device 104 is arranged upward. The material of the first seat cushion layer 101 is 30D sponge, and the second seat cushion layer 102 is high-density hard sponge.

[0107] As Figure 11 shown, this embodiment also provides an intelligent seat 200. Figure 11On the left side in the middle is the overall structure diagram of the intelligent seat 200, and on the right side is the exploded schematic diagram of the intelligent seat 200. The intelligent seat 200 includes a seat bracket 201, a support plate 202, a heart impact signal acquisition sensing device 104, a square frame 204, a first sponge layer 206, a second sponge layer 205, and an outer surrounding sponge 207. The support plate 202 is supported by four legs of the seat bracket 201. The heart impact signal acquisition sensing device 104 is installed on the support plate 202, and the first dielectric layer 10 of the heart impact signal acquisition sensing device 104 faces upward. The square frame 204 is installed on the support plate 202 and the middle of the square frame 204 is hollow. The heart impact signal acquisition sensing device 104 is located in the middle of the square frame 204. The first sponge layer 206 and the second sponge layer 205 are sequentially located above the square frame 204 from top to bottom. The outer surrounding sponge 207 covers the whole seat bracket 201.

[0108] In summary, the seat provided in this embodiment can serve as a daily household tool and can also conveniently monitor the health of the human body.

[0109] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A cardiogenic shock signal acquisition and sensing device, characterized in that: It includes a first dielectric layer (10), a pressure-sensitive layer (20), a second dielectric layer (30), and a control host (40). The pressure-sensitive layer (20) is fixedly installed between the first dielectric layer (10) and the second dielectric layer (30), and the pressure-sensitive layer (20) is in contact with the first dielectric layer (10) and the second dielectric layer (30). The cross-sectional area of the first dielectric layer (10) is larger than that of the pressure-sensitive layer (20), and the first dielectric layer (10) always maintains a gap with the second dielectric layer (30) when under pressure within the range of human body weight.

2. The cardiac impact signal acquisition and sensing device according to claim 1, characterized in that: The first dielectric layer (10) is made of a rigid material.

3. The cardiac impact signal acquisition and sensing device according to claim 2, characterized in that: The second dielectric layer (30) is made of a rigid material, and the cross-sectional area of the second dielectric layer (30) is larger than that of the pressure-sensitive layer (20).

4. The heart impact signal acquisition and sensing device according to claim 3, characterized in that: It further includes a connecting piece (60), and the connecting piece (60) is made of a rigid material. The connecting piece (60) connects the first dielectric layer (10) and the second dielectric layer (30) together, and the first dielectric layer (10) and the second dielectric layer (30) are relatively fixed in the transverse direction.

5. The heart impact signal acquisition and sensing device according to claim 4, characterized in that: At least three pairs of coaxial first connection holes (11) and second connection holes (31) are respectively formed on the first dielectric layer (10) and the second dielectric layer (30). The connecting piece (60) passes through the first connection holes (11) and the second connection holes (31) of the first dielectric layer (10) and the second dielectric layer (30) to fixedly connect the first dielectric layer (10) and the second dielectric layer (30) together.

6. The cardiac impact signal acquisition and sensing device according to claim 5, characterized in that: On the surfaces of the first dielectric layer (10) and the second dielectric layer (30) away from the pressure-sensitive layer (20), a circle of grooves (12) are respectively formed along the perimeters of the first connection holes (11) and the second connection holes (31). The connecting piece (60) includes a connecting portion (61) and two abutting portions (62) respectively located at opposite ends of the connecting portion (61). The connecting portion (61) passes through the first connection holes (11) and the second connection holes (31), and the two abutting portions (62) at both ends of the connecting portion (61) are respectively located in the grooves (12) of the first dielectric layer (10) and the second dielectric layer (30), and the abutting portions (62) limit the connecting portion (61) in the transverse direction.

7. The cardiac impact signal acquisition and sensing device according to claim 6, characterized in that: The length of the connecting portion (61) of the connecting piece (60) is greater than the distance between the bottoms of the grooves (12) of the first dielectric layer (10) and the second dielectric layer (30) and not greater than 1 mm, and the height of the connecting portion (61) is less than the height of the grooves (12) and at least 1 mm less.

8. The cardiac impact signal acquisition and sensing device according to claim 1, characterized in that: It further includes an acceleration sensor and a control host (40). The control host (40) is configured to collect the electrical signals converted from the vibration signals by the pressure-sensitive layer (20) and generate a ballistocardiogram from the collected electrical signals. The acceleration sensor is signal-connected to the control host (40), and the acceleration sensor is used to sense the pressure received by the first dielectric layer (10).

9. The cardiac impact signal acquisition and sensing device according to claim 8, characterized in that: The control host (40) includes a wake-up module. The wake-up module is signal-connected to the acceleration sensor. When the acceleration sensor senses a pressure exceeding a set threshold, the wake-up module wakes up the control host (40).

10. The cardiac impact signal acquisition and sensing device according to claim 8, characterized in that: The control host (40) includes a direction recognition module. The direction recognition module is signal-connected to the pressure-sensitive layer (20), and the direction recognition module is used to recognize the direction of the pressure sensed by the acceleration sensor.

11. The cardiogenic shock signal acquisition and sensing device according to claim 8, characterized in that: The control host (40) includes a filtering module. The filtering module is signal-connected to the pressure-sensitive layer (20). When the acceleration sensor senses a pressure exceeding a set threshold on the pressure-sensitive layer (20) and inputs this part of the pressure as a noise source, the filtering module filters the noise source.

12. A seating furniture, characterized in that: It includes a ballistocardiogram signal acquisition and sensing device according to any one of claims 1-11. The ballistocardiogram signal acquisition and sensing device is disposed below the load-bearing surface of the seat for bearing a human body.

Images