Structure level mechanical decoupling mattress for cardiac impact map acquisition and method of use

Abstract

The present application relates to the technical field of vital sign monitoring, and discloses a structure-level mechanical decoupling mattress for ballistocardiogram acquisition and a use method thereof.The mattress is sequentially provided with a covering buffer layer, a bimodal mechanical decoupling core layer, a drawable waterproof sensing core cabin, a low-resolution body pressure positioning matrix and a base layer in the thickness direction.The bimodal mechanical decoupling core layer forms a micro-bridge vertical conduction path and a damping groove-lateral energy dissipation cavity disturbance bypass on the elastic bearing base.The low-resolution body pressure positioning matrix acquires a body pressure sequence, which is used to calculate the body shape, sleeping posture and chest cavity projection area, so as to control the PVDF unit gating, preamplifier gain and microcavity target air pressure.The reference disturbance acquisition area is composed of PVDF reference units arranged near the non-chest cavity pressure-bearing area or the lateral energy dissipation cavity, and is used for common-mode disturbance cancellation.The present application improves the acquisition accuracy and stability under different body shapes and sleeping postures by means of structure-level disturbance shunting, dynamic activation and quality gating output of effective BCG signal segments.

Description

Technical Field

[0001] This invention relates to the fields of non-contact vital sign monitoring, smart mattresses, and medical rehabilitation equipment, and particularly to a structurally decoupled mechanical mattress for cardiac impaction imaging and its usage method. Background Technology

[0002] Cardiac impaction signals are low-amplitude mechanical micro-vibrations caused by the beating of the human heart. These signals can be non-intrusively collected by piezoelectric sensors placed inside the mattress and used to obtain information on heart rhythm, respiratory vibrations, and body movement. Existing solutions related to mattress or bedside sleep monitoring mainly fall into the following three categories.

[0003] The first type involves placing pressure sensors inside the mattress to create a pressure heatmap or classify sleeping positions by increasing sensor density. This type of solution mainly describes static or low-frequency pressure distribution, while mattress-type BCG (Body Pressure Gauge) involves low-amplitude mechanical micro-vibrations. The disturbance amplitudes generated by turning over, bed frame collisions, and limb movements are significantly higher than those of the BCG, and their frequency bands overlap. When high-amplitude disturbances cause front-end saturation or nonlinear distortion before entering the analog-to-digital conversion circuit, it is difficult to recover the original BCG waveform by relying solely on digital filtering or pressure matrix correction.

[0004] The second type involves fixing the sleep monitoring sensor between the foam, latex, or spring layers of the mattress and outputting sleep reports via an external terminal. This fixed, sandwiched structure makes it difficult to replace, disinfect, calibrate, and bypass faulty pathways of the sensor without disassembling the mattress, which is not suitable for long-term continuous use in multi-bedroom settings such as hospital wards and nursing homes.

[0005] The third category combines millimeter-wave radar, pressure matrix, and IoT platform algorithms in smart mattresses or bedside devices to output disease risk probabilities or sleep health indices. While this type of solution is related to bedside monitoring, it typically concentrates disturbance suppression and judgment on the backend model. If the mechanical transmission path within the mattress does not distinguish between micro-vibrations of the heartbeat and high-amplitude disturbances such as turning over or bed frame vibrations, the quality of the front-end acquisition is still affected by the mattress material structure and sensor coupling state. Therefore, it is necessary to first establish physiological micro-vibration transmission paths and energy dissipation paths for body movement disturbances at the mattress structural layer, and then combine this with dynamic sensor activation and quality gating processing. Summary of the Invention

[0006] The purpose of this invention is to solve the problems that, during the acquisition of cardiac impact maps using mattress-type PVDF sensors, low-amplitude micro-vibrations of the heartbeat are easily drowned out by high-amplitude disturbances such as turning over, bed frame vibration, and limb movement, making it difficult to maintain the fixed interlayer sensor, and that blind spots are easily formed in the fixed acquisition area under different body types and sleeping positions.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: to provide a structural mechanical decoupling mattress for cardiac impact image acquisition, including a signal processing host on the side of the mattress and a covering buffer layer, a dual-modal mechanical decoupling core layer, a retractable waterproof sensing core chamber, a low-resolution body pressure positioning matrix and a base layer stacked from top to bottom along the thickness direction of the mattress.

[0008] The dual-modal mechanical decoupling core layer includes an elastic bearing matrix, a flexible microbridge conduction sublayer, a shear damping groove sublayer, a lateral energy dissipation cavity sublayer, and an adjustable air pressure microcavity array sublayer, which are used to form a first mechanical channel for conducting low-amplitude vertical micro-vibrations of the heartbeat and a second mechanical channel for conducting high-amplitude disturbance vibrations generated by turning over, bed frame vibration, or limb movement.

[0009] The retractable waterproof sensing core is equipped with a PVDF piezoelectric film physiological sensing array consisting of several PVDF units and several reference perturbation sensing units. The PVDF units and the reference perturbation sensing units use the same or frequency-matched PVDF piezoelectric film sensors, and each PVDF unit can be independently selected. The PVDF units are used to collect low-amplitude vertical micro-vibrations of the heartbeat transmitted through the first mechanical channel, and the reference perturbation sensing units are used to collect high-amplitude perturbation vibrations transmitted through the second mechanical channel. The low-resolution body pressure positioning matrix is ​​used to collect body pressure sequences.

[0010] The mattress side signal processing host controls the gating of the PVDF unit, the gain of the PVDF unit's preamplifier, and the mechanical coupling stiffness of the dual-mode mechanical decoupling core layer according to the body pressure sequence, and performs common-mode disturbance cancellation on the output of the gating PVDF unit according to the output of the reference disturbance sensing unit.

[0011] Preferably, the elastic bearing substrate is located between the covering buffer layer and the removable waterproof sensing core, with the side closer to the covering buffer layer as the upper side and the side closer to the removable waterproof sensing core as the lower side. The flexible microbridge conduction sublayer is disposed on the upper surface of the elastic bearing substrate, the shear damping groove sublayer is formed inside the elastic bearing substrate, the lateral energy dissipation cavity sublayer is formed on the side edge of the elastic bearing substrate, and the adjustable air pressure microcavity array sublayer is disposed between the lower surface of the elastic bearing substrate and the upper wall of the removable waterproof sensing core.

[0012] The flexible microbridge conductive sublayer includes multiple microbridge conductive units arranged in an array within the thoracic projection candidate area of ​​the elastic support substrate. Each microbridge conductive unit protrudes from the upper surface of the elastic support substrate toward the covering buffer layer and is integrally formed with the elastic support substrate by silicone, thermoplastic elastomer or low-hardness polyurethane, or fixed to the upper surface of the elastic support substrate by hot pressing, bonding or embedding.

[0013] The shear damping groove sublayer includes several grooves formed inside the elastic bearing matrix and located between adjacent microbridge conduction units. The grooves extend along the width direction of the mattress or obliquely to the side edge of the elastic bearing matrix and are staggered with the microbridge conduction units.

[0014] The lateral energy dissipation cavity layer includes a cavity formed on the side edge of the elastic bearing substrate and connected to the end of one or more shear damping grooves; the end of the groove refers to the end of the shear damping groove that extends from the candidate area of ​​the thoracic cavity projection towards the width of the mattress or obliquely and reaches the side edge of the elastic bearing substrate; the cavity extends along the side edge of the elastic bearing substrate and receives the lateral shear vibrations derived from the shear damping grooves at the connection point, and the cavity is filled with viscoelastic damping material;

[0015] The adjustable pneumatic microcavity array sublayer is used to adjust the mechanical coupling stiffness of the dual-modal mechanical decoupling core layer. It includes multiple pneumatic microcavity units surrounded by a flexible sealing membrane and a supporting substrate. Each pneumatic microcavity unit is independently or partitioned and connected to the air manifold, micro air pump and valve group. The first mechanical channel passes through the microbridge conduction unit and the pneumatic microcavity unit in sequence, and the second mechanical channel passes through the shear damping groove and the lateral energy dissipation cavity in sequence.

[0016] Preferably, the PVDF piezoelectric thin film physiological sensing array includes a main chest cavity acquisition area, a neck and shoulder auxiliary acquisition area, an abdominal and lumbar body motion acquisition area, and a reference perturbation acquisition area. The main chest cavity acquisition area is a fixed hardware area pre-arranged in the middle of the sensing core chamber to cover the chest cavity position of different body types. The chest cavity projection area output by the low-resolution body pressure positioning matrix is ​​a sub-region dynamically calculated based on the current body pressure sequence. The chest cavity projection area is mapped onto the main chest cavity acquisition area and its adjacent neck and shoulder auxiliary acquisition area or abdominal and lumbar body motion acquisition area to determine the PVDF to be selected. The unit; the neck and shoulder auxiliary acquisition area is used to supplement the acquisition when the chest cavity projection area shifts towards the head of the bed; the abdominal and lumbar body movement acquisition area is used to detect abdominal breathing, turning over, and body movement; the reference disturbance acquisition area consists of one or more reference disturbance sensing units, which are PVDF piezoelectric film sensors that are the same as or have the same frequency response as the PVDF unit, and are set in the non-chest cavity pressure area or near the lateral discharge end of the lateral energy dissipation cavity, and are used to acquire bed frame vibration, turning over vibration, and environmental common mode disturbances without directly using them as the cardiac impact map output channel.

[0017] Preferably, the body pressure sequence includes the pressure values, valid status of the sampling points, and off-bed status of each pressure sampling point arranged according to the sampling time.

[0018] Preferably, the system further includes a sensor activation control module, which comprises a body pressure sequence receiving unit, a parameter calculation unit, a body shape and sleeping posture determination unit, a chest cavity projection positioning unit, and a control output unit. The parameter calculation unit calculates the pressure centroid, effective body pressure area, pressure distribution length, and local pressure change rate based on the body pressure sequence acquired by the low-resolution body pressure positioning matrix. The body shape and sleeping posture determination unit determines the body shape pattern and sleeping posture based on the parameters. The chest cavity projection positioning unit determines the chest cavity projection area based on the pressure centroid, effective body pressure area, pressure distribution length, and body shape pattern. The control output unit outputs the PVDF unit gating combination, preamplifier gain, and target air pressure of the adjustable air pressure microcavity array sublayer based on the body shape pattern, sleeping posture, and chest cavity projection area.

[0019] Preferably, it also includes a sensor core self-test calibration module, which includes a mechanical calibration excitation unit, an electrical testing unit, a channel response calculation unit, and a fault bypass unit. The mechanical calibration excitation unit is used to input a mechanical calibration signal with known frequency and amplitude. The electrical testing unit is used to input test pulses to the PVDF sensor array, connector, and preamplifier circuit to detect open circuits, short circuits, poor contacts, or abnormal front-end circuits. The channel response calculation unit calculates the mechanical channel health coefficient H_mech based on the mechanical calibration response and the electrical channel health coefficient H_elec based on the electrical testing response. When H_mech or H_... When elec is below the unavailable threshold, the fault bypass unit will remove the corresponding PVDF unit from the gating candidate list; when H_mech and H_elec are between the unavailable threshold and the normal threshold, the channel fusion coefficient of the PVDF unit in the multi-channel BCG weighted fusion is reduced; the multi-channel BCG weighted fusion refers to performing reference disturbance cancellation and heartbeat band filtering on the outputs of multiple PVDF units that have not been removed in sequence, and then performing weighted summation according to the normalized channel fusion coefficient to obtain the fused BCG waveform. The channel fusion coefficient is jointly determined by the mechanical channel health coefficient, electrical channel health coefficient and signal quality coefficient of the corresponding channel.

[0020] This invention also provides a method for using a structural-level mechanical decoupling mattress for cardiac impact mapping, based on any of the above-described structural-level mechanical decoupling mattresses for cardiac impact mapping, comprising:

[0021] Collect body pressure sequences and calculate body shape patterns, sleeping positions, and chest projection areas;

[0022] The target air pressure of the adjustable air pressure microcavity array sublayer is set according to the body shape pattern;

[0023] The PVDF unit gating combination is determined based on body shape pattern, sleeping posture, and chest projection area, and the preamplifier gain is configured accordingly.

[0024] Using the output of the reference disturbance sensing unit as a reference, common-mode disturbance cancellation is performed on the output of the gating PVDF unit;

[0025] Calculate the peak-to-noise ratio SNR_ch, J-wave template correlation coefficient r_J, and reference perturbation residual ratio E_ref for each gated channel. SNR_ch is used to characterize the amplitude quality of the J-wave candidate peak relative to the noise floor, r_J is used to characterize the consistency between the current cardiac impact map morphology and the J-wave template, and E_ref is used to characterize the residual degree of reference perturbation energy after perturbation cancellation.

[0026] Channels that simultaneously meet the following criteria and are not marked as faulty are identified as valid channels: SNR_ch is not lower than the peak-to-noise ratio threshold, r_J is not lower than the correlation threshold, E_ref is not higher than the residual threshold, and the channel is not marked as faulty. The ratio of the number of valid channels to the number of selected channels is used as the effective signal ratio. When the effective signal ratio is not lower than the ratio threshold, the signal output of the valid channel after disturbance cancellation and cardiac impaction band filtering is the valid BCG signal segment. When the effective signal ratio is lower than the ratio threshold, the adjacent PVDF unit is expanded and activated and re-evaluated.

[0027] Preferably, the calculation of body shape pattern, sleeping posture, and chest projection area includes the following steps:

[0028] The low-resolution body pressure positioning matrix collects the body pressure sequence of each pressure sampling point over time and sends it to the sensor activation control module;

[0029] The sensor activation control module calculates the pressure centroid, effective body pressure area, pressure distribution length, and local pressure change rate based on the body pressure sequence.

[0030] Body type patterns for children, standard adults, or large adults are determined based on effective body pressure area and pressure distribution length.

[0031] The supine, left lateral, right lateral, or off-bed position is determined based on the lateral offset of the center of gravity and the rate of pressure change in the left and right local areas.

[0032] The thoracic projection area is determined based on the pressure center of gravity, pressure distribution length, and body shape pattern.

[0033] Preferably, setting the target pressure of the adjustable pressure microcavity array sublayer according to the body shape pattern includes:

[0034] In standard adult mode, the target air pressure of the adjustable pressure microcavity array sublayer is set to the standard reference air pressure P_std, which is 100kPa to 130kPa. In child mode, the target air pressure is set to 65% to 80% of P_std. In large adult mode, the target air pressure is set to 110% to 120% of P_std. In each mode, the target air pressure is finely adjusted in a closed loop according to whether the amplitude of the effective BCG signal segment is lower than the noise threshold or higher than the saturation threshold.

[0035] Preferably, the step of determining the PVDF unit gating combination and configuring the preamplifier gain based on body shape pattern, sleeping posture, and chest projection area includes:

[0036] In the standard adult supine mode, activate 3×4 PVDF units in the main acquisition area of ​​the chest cavity that overlap with the chest cavity projection area, and configure the standard gain G_std and the standard ADC reference voltage.

[0037] In child mode, activate the 2×3 PVDF units in the center of the main chest cavity acquisition area, configure the preamplifier gain to 2 to 4 times G_std, and switch the ADC reference voltage to ±0.3V;

[0038] In the large adult mode, activate the entire array of the main chest cavity acquisition area and adjacent auxiliary columns;

[0039] In left or right lateral decubitus mode, the PVDF column on the side with the offset of the pressure center of gravity is activated first, and when the effective signal ratio on that side is insufficient, it is extended to the adjacent column.

[0040] The present invention has the following beneficial effects:

[0041] (1) The present invention enables the BCG signal to be physically decoupled before entering the ADC through structural mechanical decoupling, thereby reducing the dependence on the back-end black box model; the reference disturbance acquisition area is arranged near the lateral energy dissipation cavity to provide a more structurally relevant reference signal for adaptive cancellation.

[0042] (2) The present invention uses a low-resolution volume pressure matrix closed-loop control adjustable air pressure microcavity to reduce the equivalent stiffness in child mode to improve the low amplitude BCG conduction ratio, and to increase the stiffness in large adult mode to avoid PVDF saturation.

[0043] (3) The self-testing bypass mechanism of the sensing core of the present invention allows the remaining channels to continue to work effectively when a single PVDF channel ages or is infiltrated by liquid.

[0044] (4) The present invention sets up a clinical deployment interface to output a quantifiable hardware status diagnostic package, enabling the host software to decide whether to adopt the vital signs output for a certain period of time based on signal quality indicators, rather than blindly trusting the data for the entire period of time.

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the embodiments. Attached Figure Description

[0046] Figure 1 This is a structural schematic diagram of a structurally decoupled mattress for cardiac impact mapping according to an embodiment of the present invention.

[0047] Figure 2 This is a cross-sectional schematic diagram showing the positional relationship between the elastic bearing substrate, the flexible microbridge conduction sublayer, the shear damping groove sublayer, the lateral energy dissipation cavity sublayer, the adjustable air pressure microcavity array sublayer, and the upper wall of the sensing core compartment in an embodiment of the present invention.

[0048] Figure 3 This is a schematic diagram of body shape / sleeping posture recognition and dynamic activation of the PVDF sensor according to an embodiment of the present invention;

[0049] Figure 4 This is a block diagram of the hardware signal chain, reference disturbance cancellation, quality assessment, and closed-loop control in an embodiment of the present invention.

[0050] Figure 5 This is a schematic diagram of the retractable waterproof sensor core, self-test calibration module, and clinical deployment interface structure according to an embodiment of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0052] See Figure 1 As shown, an embodiment of the present invention provides a structural-level mechanical decoupling mattress for cardiac impact mapping, comprising:

[0053] It includes a signal processing host and a multi-layered material layer; the multi-layered material layer uses a PVDF sensor array to collect vibration signals; the signal processing host performs common-mode disturbance cancellation on the vibration signals.

[0054] The material layers are stacked sequentially from top to bottom along the thickness direction of the mattress as follows:

[0055] The cover buffer layer is in direct contact with the user and is used to isolate the underlying material, thus providing a cushioning function.

[0056] A dual-modal mechanical decoupling core layer is used to form two independent mechanical conduction channels, which conduct cardiac vibrations and disturbance vibrations respectively.

[0057] The retractable waterproof sensing core uses a PVDF sensing array to collect vibration signals; it separately collects disturbance vibration signals and transmits them to a signal processing host to cancel common-mode disturbances in the vibration signals; each PVDF unit in the PVDF sensing array is an independently controlled piezoelectric thin film sensor.

[0058] A low-resolution body pressure localization matrix is ​​used to acquire pressure signals; the pressure signals are used to determine the thoracic cavity projection area, thereby determining the PVDF unit that needs to be gated.

[0059] The base layer provides support for the mattress's shape.

[0060] Specifically, the covering and cushioning layer includes a skin-friendly covering layer and an elastic and comfortable cushioning layer. The skin-friendly covering layer is made of removable and washable antibacterial fabric.

[0061] Specifically, the dual-modal mechanical decoupling core layer is positioned between the elastic comfort cushioning layer and the retractable waterproof sensing core chamber. It includes an elastic support matrix, a flexible microbridge conduction sublayer, a shear damping groove sublayer, a lateral energy dissipation cavity sublayer, and an adjustable air pressure microcavity array sublayer. The flexible microbridge conduction sublayer and the shear damping groove sublayer are formed in different regions of the same elastic support matrix: the microbridge conduction unit is located in the chest cavity projection candidate area (this can be configured according to the actual application and model, for example, located in the upper half of the mattress, or only in the middle third of the upper half, etc.); the shear damping groove is located between adjacent microbridge conduction units and extends laterally towards the mattress; the lateral energy dissipation cavity is located at the lateral end of the shear damping groove. The flexible microbridge conduction sublayer is positioned on the upper surface of the elastic support matrix, the shear damping groove sublayer is formed inside the elastic support matrix, the lateral energy dissipation cavity layer is formed on the side edge of the elastic support matrix and communicates with the shear damping groove, and the adjustable air pressure microcavity array is positioned between the lower surface of the elastic support matrix and the upper wall of the sensing core chamber. See [link to relevant documentation]. Figure 2 As shown in the figure, multiple blue units represent an adjustable air pressure microcavity array. The upper horizontal line represents a flexible sealing membrane connected to the flexible microbridge conduction sublayer, and the lower horizontal line represents the upper wall of the sensing core chamber or the supporting substrate. Each blue unit is an air pressure microcavity surrounded by a flexible sealing membrane and a supporting substrate. It can be connected to the airway manifold independently or in sections according to the chest cavity, neck and shoulder area and waist and abdomen area, and the internal air pressure can be adjusted by a micro air pump and valve group.

[0062] The above sub-layers represent different structural functional areas. It is not required that all four layers be stacked continuously along the thickness direction and work together to form two mechanical conduction channels.

[0063] Channel 1: Low-amplitude vertical micro-vibrations of the heartbeat are transmitted downwards through the flexible microbridge conduction sublayer to the PVDF piezoelectric thin film physiological sensing array;

[0064] Channel 2: High-amplitude disturbances such as turning over and bed frame vibration are introduced into the lateral energy dissipation cavity layer through the lateral shear path of the shear damping groove sub-layer and dissipated by the viscoelastic damping material.

[0065] The flexible microbridge conduction sublayer is arranged only within the candidate region of the thoracic projection of the elastic bearing substrate. Each microbridge conduction unit is an arch-shaped, column-shaped, or rib-shaped elastic structure made of silicone, thermoplastic elastomer, or low-hardness polyurethane. It can be integrally molded with the elastic bearing substrate or fixed by hot pressing, bonding, or embedding. Shear damping grooves are formed in the elastic bearing substrate and are offset from the microbridge conduction units, so that the low-amplitude vertical conduction path and the high-amplitude lateral energy dissipation path are spatially isolated from each other.

[0066] Specifically, the flexible microbridge conductive sublayer is arranged in an array in the thoracic cavity projection candidate area of ​​the elastic support substrate. Each microbridge conductive unit is an arch-shaped, column-shaped, or rib-shaped elastic structure made of silicone, thermoplastic elastomer, or low-hardness polyurethane (Shore A 10°~40°). It can be integrally molded with the elastic support substrate or fixed by hot pressing, bonding, or embedding. The center-to-center distance between adjacent microbridges is 5mm~30mm, the width of the microbridge is 2mm~20mm, and the thickness is 0.5mm~8mm. The upper end of the microbridge conductive unit receives the vertical micro-vibrations of the thoracic cavity from the covering buffer layer, and the lower end corresponds to one or more pneumatic microcavity units. Shear damping grooves are formed in the elastic support matrix and are arranged alternately along the width of the mattress or diagonally. The grooves are offset from the microbridge conduction units. The groove width is 3mm to 30mm and the groove depth is 5mm to 50mm. The lateral end of the groove is the groove end formed by the groove extending from the candidate area of ​​the thoracic cavity projection along the width of the mattress or diagonally to the side edge of the elastic support matrix. The lateral energy dissipation cavity is a strip cavity extending along the side edge of the elastic support matrix or a cavity group composed of multiple spaced cavities, and is connected to the groove end of at least one shear damping groove through a connecting port. The cavity is filled with a viscoelastic damping material with a loss factor η of not less than 0.15.

[0067] Specifically, the flexible microbridge conductive sublayer of the dual-modal mechanical decoupling core layer is manufactured with two microbridge width specifications: one for children and one for adults. The microbridge width in the children's area is 2mm to 8mm, and the microbridge width in the adult area is 8mm to 20mm. The sensor activation control module activates only the PVDF sensing unit directly below the microbridge in the children's area in children's mode, and activates the PVDF sensing unit directly below the microbridge in the adult area in adults' mode.

[0068] Specifically, the adjustable pressure microcavity array sublayer comprises multiple flexible, sealed air cavities formed by hot pressing or bonding medical-grade TPU films, silicone rubber films, or thermoplastic elastomer films to a supporting substrate. Each pressure microcavity unit is connected to an airway manifold via a micro-inlet and is independently or zone-regulated by a pressure regulating assembly consisting of a micro-pump, an inlet valve, an outlet valve, and a pressure sensor. Pressure regulation alters the equivalent coupling stiffness between the flexible microbridge conductive sublayer and the PVDF piezoelectric film physiological sensor array, thereby changing the BCG amplitude received by the PVDF sensor unit and the risk of overpressure saturation. In standard adult mode, the reference pressure P_std can be set to 100 kPa–130 kPa; in pediatric mode, it is reduced to 65%–80% of P_std; and in large adult mode, it is increased to 110%–120% of P_std.

[0069] Specifically, the flexible microbridge conduction sublayer and the shear damping groove sublayer together constitute a three-dimensional joint decoupling structure of amplitude, direction, and frequency, which meets the following verifiable indicators: Under the same standard bed frame vibration excitation conditions (excitation amplitude A_frame = 5g, frequency f = 1Hz~20Hz), compared with the control mattress without a dual-modal mechanical decoupling core layer, the residual power of bed frame vibration disturbance in the PVDF signal of the main acquisition area of ​​the chest cavity is reduced by no less than 15dB; the reference disturbance residual ratio E_ref does not exceed 20%.

[0070] Specifically, the retractable waterproof sensor core contains a built-in PVDF piezoelectric film physiological sensor array, which includes a main chest cavity acquisition area, a neck and shoulder auxiliary acquisition area, an abdominal and lumbar body movement acquisition area, and a reference perturbation acquisition area. The main chest cavity acquisition area is a fixed hardware area pre-arranged in the center of the sensor core to cover the possible locations of the chest cavity for different body types; the chest cavity projection area R_chest is a sub-region dynamically calculated by the sensor activation control module based on the current body pressure sequence, and the two are not the same concept. The system maps R_chest to the main chest cavity acquisition area and calls the adjacent PVDF unit of the neck and shoulder auxiliary acquisition area or the abdominal and lumbar body movement acquisition area when R_chest crosses the boundary of the main acquisition area. The neck and shoulder auxiliary acquisition area is used to supplement the acquisition of cardiac micro-vibrations when the chest cavity shifts towards the head of the bed, and the abdominal and lumbar body movement acquisition area is used to detect abdominal breathing, turning over, and large-amplitude body movements.

[0071] The reference disturbance acquisition area is a functional region within the sensing core, consisting of one or more reference disturbance sensing units. These units are PVDF piezoelectric film sensors made of the same material or with the same frequency response as the PVDF unit in the main thoracic acquisition area. The piezoelectric diaphragm is fixed to a flexible FPC or a thin elastic support sheet and encapsulated in TPU. The reference disturbance sensing units are located in non-thoracic pressure-bearing areas or near the lateral discharge end of lateral energy-dissipating chambers. They preferentially pick up bed frame vibrations, turning vibrations, and environmental common-mode disturbances. Their output serves only as a common-mode disturbance cancellation reference and is not directly used as the vital signs output for cardiac impaction.

[0072] Specifically, the pull-out waterproof sensor core compartment adopts a side drawer-type structure, equipped with a mechanical foolproof connector, an electrical identification terminal, and a locking structure, supporting replacement, disinfection, or repair without disassembling the mattress body; the sensor core compartment is equipped with a labyrinth-style flow channel and a humidity indicator electrode. The labyrinth-style flow channel is used to prevent cleaning fluid or body fluid from entering the sensor core compartment along the connector, and the humidity indicator electrode triggers a maintenance prompt when liquid intrusion occurs.

[0073] Specifically, the retractable waterproof sensor core also includes a dry and wet isolation compartment, a replaceable outer isolation cover, and a unique identification terminal; the unique identification terminal is an EEPROM or resistor code that records the sensor core model, calibration version, number of disinfection cycles, and number of insertions and removals; when the humidity indicator electrode detects liquid intrusion, the signal processing host on the side of the mattress stops outputting vital signs, but retains the out-of-bed status and maintenance prompt output.

[0074] Specifically, the low-resolution body pressure positioning matrix has at least 12 sampling points along its length and at least 6 sampling points along its width, with a sampling frequency of at least 1Hz. At each sampling moment, the matrix outputs the pressure value p_ij(t), the effective state of the sampling point, and the state of being off the bed for each pressure sampling point. Data from multiple consecutive sampling moments constitute a body pressure sequence. The low-resolution body pressure positioning matrix is ​​responsible for collecting pressure values. The pressure centroid coordinates, effective body pressure area S_eff, pressure distribution length D_p, local pressure change rate, and thoracic projection area R_chest are calculated by the sensor activation control module. D_p is the maximum continuous span along the mattress length of the sampling point where the pressure value exceeds the effective pressure threshold; the local pressure change rate is the ratio of the difference in pressure values ​​between adjacent sampling moments within a preset local area to the sampling time interval; R_chest is dynamically determined based on the pressure centroid, S_eff, D_p, and body shape pattern.

[0075] Specifically, the mattress side signal processing host and the mattress body use a sealed quick-connect interface to meet the repeated cleaning and maintenance requirements of medical institutions and elderly care institutions. The mattress side signal processing host includes a low-noise charge amplifier circuit, a differential analog-to-digital converter circuit, a reference disturbance cancellation circuit, an embedded processor, a wireless communication module, and a local storage module; the reference disturbance cancellation circuit uses the signal of the reference disturbance acquisition area as a reference to perform common-mode disturbance cancellation on the signal of the main chest cavity acquisition area in the analog or digital domain; the sampling rate is not less than 250Hz, and the analog-to-digital conversion accuracy is not less than 16bit.

[0076] Specifically, the sensor activation control module includes a body pressure sequence receiving unit, a parameter calculation unit, a body shape classification unit, a sleeping posture recognition unit, a chest cavity projection positioning unit, a unit selection switch, and a gain configuration unit. The body shape classification unit outputs at least three modes: child, standard adult, and large adult. The sleeping posture recognition unit outputs at least four states: supine, left lateral, right lateral, and out-of-bed. In the standard adult supine mode, the 3×4 PVDF units overlapping with R_chest are activated and configured with a standard gain G_std and a standard ADC reference voltage. In the child mode, the central 2×3 PVDF units are activated, with the gain set to 2 to 4 times G_std, and the ADC reference voltage switched to ±0.3V. In the large adult mode, the entire array of the main chest cavity acquisition area and adjacent auxiliary columns are activated. In the lateral mode, the PVDF column on the side of the pressure center of gravity offset is activated first.

[0077] See Figure 5 As shown, the mattress also includes a sensor core self-test calibration module and a clinical deployment interface unit. The blue arrows represent physiological signal acquisition and host signal chains, the orange arrows represent self-test calibration and maintenance safety signals, and the green arrows represent clinical deployment and care.

[0078] The sensor module's self-test calibration module includes a mechanical calibration excitation unit, an electrical testing unit, a channel response calculation unit, and a fault bypass unit. The mechanical calibration excitation unit, in the off-bed state, inputs a mechanical calibration signal of known frequency and amplitude to detect the microbridge conduction path, the gas pressure microcavity coupling state, and the PVDF mechanical response. The electrical testing unit inputs test pulses to the PVDF channels, connectors, and preamplifier circuit to detect open circuits, short circuits, poor contacts, and front-end circuit abnormalities. The channel response calculation unit calculates H_mech and H_elec respectively. When either coefficient is below the unusable threshold, the fault bypass unit removes the corresponding channel from the selection candidate list; when both coefficients are between the unusable threshold and the normal threshold, the channel fusion coefficient in the multi-channel BCG weighted fusion is reduced, i.e., the channel's amplitude contribution to the fused BCG waveform is reduced, rather than changing the activation voltage of the PVDF unit itself. Specifically, let the effective channel set be C_eff, and the signal of the c-th channel after reference perturbation cancellation and filtering in the 0.8Hz–20Hz frequency band be x_c(t). The signal quality coefficient Q_c is obtained by normalizing the peak-to-noise ratio SNR_ch, the J-wave template correlation coefficient r_J, and the reference perturbation residual ratio E_ref. First, calculate the unnormalized weight β_c = H_mech,c × H_elec,c × Q_c, and then calculate the channel fusion coefficient α_c = β_c / Σ(k∈C_eff)β_k. The fused BCG waveform is y(t) = Σ(c∈C_eff)α_c × x_c(t). The β_c of low-confidence channels is multiplied by a penalty factor less than 1, and the α_c of unusable channels is set to 0. Thus, while preserving the heartbeat morphology of healthy channels, the influence of aging, damp, or abnormally connected channels on the fused waveform is reduced.

[0079] The clinical deployment interface unit includes a bed-binding storage unit, a sensor core identification unit, a hardware status encapsulation unit, and a communication interface unit. The hardware status encapsulation unit generates a hardware status diagnostic package, which includes the mattress online status, effective PVDF channel ratio, reference disturbance residual ratio E_ref, bed-off status, continuous pressure duration, and sensor core disinfection and maintenance status. The communication interface unit sends the hardware status diagnostic package to the nurse station, doctor's workstation, or nursing terminal. The hardware status diagnostic package does not contain disease diagnosis probability or sleep score, but only expresses the quantifiable status of the sensor hardware layer.

[0080] See Figure 3 and Figure 4 As shown in the figure, an embodiment of the present invention provides a low-resolution body pressure closed-loop activation method for a structurally decoupled mattress for cardiac impact mapping, comprising the following steps:

[0081] S0: When the mattress is in the off-bed state, the mechanical calibration excitation unit outputs a mechanical calibration signal with a known frequency and amplitude, collects the response amplitude, phase delay, and noise floor of each PVDF channel, and calculates H_mech; the electrical test unit inputs test pulses to the PVDF channels, connectors, and preamplifier circuit, and calculates H_elec based on the pulse response or open / short circuit state; during mechanical calibration, the reference disturbance residual benchmark E_ref_base is calculated as the correction benchmark for the subsequent reference disturbance residual threshold;

[0082] S1: The low-resolution body pressure positioning matrix collects the pressure value p_ij(t), effective state and off-bed state of each pressure sampling point at a frequency of not less than 1Hz and forms a body pressure sequence; the sensor activation control module calculates the pressure centroid coordinates (x_c, y_c), effective body pressure area S_eff, pressure distribution length D_p, local pressure change rate and thoracic projection area R_chest according to the body pressure sequence.

[0083] S2: Determine the body type pattern M_body based on S_eff and D_p, and output at least three categories: children, standard adults and large adults. D_p is the maximum continuous span of the sampling points where the pressure value exceeds the effective pressure threshold in the length direction of the mattress.

[0084] S3: Determine the sleeping posture M_pose based on the lateral offset of the pressure center of gravity |x_c| and the pressure change rate of the left and right local areas, and output at least four categories: supine, left lateral, right lateral, and off-bed; the local pressure change rate is calculated from the pressure values ​​of adjacent sampling times of the preset local area in the body pressure sequence.

[0085] S4: Select the PVDF unit combination A_active corresponding to R_chest from the PVDF sensor array according to M_body and M_pose and configure the preamplifier gain G_amp; in the standard adult supine mode, select the 3×4 PVDF units that overlap with R_chest and configure the standard gain G_std; in the side-lying mode, prioritize the selection of the PVDF column on the side of the pressure center of gravity offset.

[0086] S5: Output target air pressure P_target(M_body) to the adjustable pressure microcavity array sublayer; in standard adult mode, P_target = P_std, where P_std is 100kPa to 130kPa; in child mode, P_target is 65% to 80% of P_std; in large adult mode, P_target is 110% to 120% of P_std; P_target is finely adjusted in a closed loop according to whether the BCG amplitude is lower than the noise threshold or higher than the saturation threshold, so that the equivalent stiffness K_eff is between the lower limit stiffness K_low, which avoids the BCG being submerged by the noise floor, and the upper limit stiffness K_high, which avoids the PVDF output saturation;

[0087] S6: Using the reference disturbance acquisition area signal as a reference, common-mode disturbance cancellation is performed on each PVDF channel in A_active, and SNR_ch, r_J, and E_ref are calculated. SNR_ch represents the amplitude quality of the J-wave candidate peak relative to the noise floor, r_J represents the consistency between the current BCG shape and the J-wave template, and E_ref represents the residual degree after disturbance cancellation. Channels that simultaneously satisfy SNR_ch not lower than the peak-to-noise ratio threshold, r_J not lower than the correlation threshold, E_ref not higher than the residual threshold, and are not marked as faulty are considered valid channels. The ratio of the number of valid channels to the number of selected channels is the effective signal ratio. If the effective signal ratio is lower than the ratio threshold, adjacent PVDF units are expanded and activated and re-evaluated. Otherwise, the signals of the valid channels after disturbance cancellation and filtering in the 0.8Hz to 20Hz frequency band are normalized and weighted, and the resulting fused waveform is output as a valid BCG signal segment.

[0088] in, Figure 3 The red square indicates the PVDF unit that is activated this time; the other units are powered off. The pressure matrix is ​​only used to locate body shape / sleeping position.

[0089] Specifically, in the self-test step S0 before step S1, after confirming bed alighting, the mechanical calibration excitation unit outputs three sets of low-amplitude mechanical calibration signals at 8Hz, 12Hz, and 18Hz, acquires the response of each PVDF channel, and calculates H_mech; the electrical test unit sequentially inputs test pulses to the PVDF channel, connector, and preamplifier circuit, and calculates H_elec based on the pulse amplitude, charge / discharge time constant, and open / short circuit status; during mechanical calibration, the ratio of the energy of the reference disturbance channel to the residual disturbance energy of the physiological acquisition channel is used as E_ref_base. If H_mech or H_elec is lower than 0.6, the channel is added to the unusable list; if both are not lower than 0.8, it is listed as a priority selection channel; the remaining channels are set with a lower multi-channel fusion coefficient according to the health coefficient.

[0090] Specifically, the channel response calculation unit calculates the mechanical channel health coefficient H_mech based on the response amplitude G_c, phase delay φ_c, and noise floor N_c of each PVDF channel to the mechanical calibration signal: H_mech=w1·(G_c / G_ref)+w2·(1-|φ_c-φ_ref| / φ_max)+w3·(N_ref / N_c), where G_ref, φ_ref, and N_ref are factory calibration parameters, and w1, w2, and w3 are weighting coefficients whose sum is 1. The electrical channel health coefficient H_elec is calculated based on the ratio of the test pulse response amplitude to the reference amplitude, the charge / discharge time constant deviation, and the open / short circuit detection results, and is used to distinguish between mechanical coupling anomalies and circuit connection anomalies. E_ref_base is the reference disturbance residual benchmark measured during off-bed mechanical calibration, used to set the residual threshold for the operating phase according to θ_ref=k_θ·E_ref_base.

[0091] Specifically, the quality assessment in step S6 includes SNR_ch, r_J, E_ref, pressure center of gravity stability, and body motion percentage. SNR_ch and r_J jointly determine whether there are morphologically stable J-wave candidates with a noise floor in the channel, and E_ref determines whether the candidate is still significantly contaminated by common-mode disturbances. Only waveforms that have passed the disturbance cancellation through the above quality gating are included as valid BCG signal segments in the calculation of heart rate or respiratory parameters. The residual threshold θ_ref during the operation phase is determined by multiplying E_ref_base by the correction coefficient k_θ, where k_θ ranges from 1.2 to 2.0. When E_ref exceeds θ_ref, a low-confidence marker is output for the corresponding time period, and the output of vital sign results is restricted.

[0092] Specifically, when the low-resolution body pressure positioning matrix detects that the duration of continuous pressure on the same local area exceeds the preset threshold T_press and the number of effective turning markers in the PVDF body movement signal is zero, a continuous pressure nursing event is generated; when the body pressure matrix detects that the pressure suddenly disappears and the energy of the PVDF body movement channel suddenly increases beyond E_motion, an off-bed verification event is generated; the above events include the occurrence time, duration and reference disturbance residual ratio E_ref, which are output through the clinical deployment interface unit.

[0093] The following describes in detail the method of using the mattress according to an embodiment of the present invention through specific usage scenarios.

[0094] (1) Standard adult supine monitoring. After the user gets into bed, the low-resolution body pressure positioning matrix collects a 30-second body pressure sequence at a frequency of 1Hz, and calculates the effective body pressure area, pressure center of gravity, and chest cavity projection area. When the lateral offset of the pressure center of gravity is less than 15% of the mattress width and the chest cavity projection area is located at 35% to 55% of the length of the mattress, the system determines it to be in standard adult supine mode. The sensor activation control module activates 3×4 PVDF sensing units in the main chest cavity acquisition area and synchronously connects the reference disturbance acquisition area. In this mode, the flexible microbridge conduction sublayer maintains standard stiffness, and the adjustable air pressure microcavity array air pressure is set to 120kPa. The PVDF physiological channel sampling rate is 250Hz, and the analog-to-digital conversion accuracy is not less than 16bit. The side host performs charge amplification, differential sampling, and reference disturbance cancellation on the PVDF signal, and then calculates the signal peak-to-noise ratio, J-wave template correlation coefficient, and reference disturbance residual ratio. If the percentage of valid signals is higher than 70% for 5 consecutive minutes, the current active combination is maintained; if it is lower than 70%, the adjacent column of PVDF cells is expanded to be activated.

[0095] (2) Monitoring of low body weight in children. For children over 3 years old, when the effective body pressure area detected by the body pressure positioning matrix is ​​lower than the preset threshold T1, the system enters the child mode. In the child mode, the microcavity pressure decreases from 120 kPa to 85 kPa, and the local structural stiffness decreases by about 28%; the preamplifier gain increases from 500 times that of the standard adult mode to 1500 times; the ADC reference voltage range switches from ±1V to ±0.3V; and the 2×3 PVDF units in the center of the main acquisition area of ​​the thoracic cavity are activated. This processing can improve the PVDF output amplitude and equivalent resolution under low body weight and low amplitude cardiac excitation conditions.

[0096] (3) Monitoring of lateral and large-body-size adults. When the body pressure positioning matrix detects a lateral offset of the pressure center of gravity exceeding 15% of the mattress width, the system determines the user to be in lateral position and prioritizes activating two or three columns of PVDF units on the heavier side. When the effective body pressure area is higher than the threshold T2 and the chest cavity projection coverage widens, the system determines the user to be in large-body-size adult mode and activates the entire array of the main chest cavity acquisition area and adjacent auxiliary columns. This scheme avoids blind spots in the acquisition of fixed single-zone sensors in lateral or large-body-size users.

[0097] (4) Medical Ward Maintenance Scenario. When the mattress is used in a hospital ward, nursing staff can pull out the sensor core compartment from the side of the mattress and wipe the TPU encapsulated surface with 75% alcohol for disinfection. If a PVDF unit experiences an open circuit, short circuit, or decreased sensitivity, the system identifies the fault location through the calibration information recorded in the sensor core compartment's EEPROM and prompts for replacement of the sensor core compartment, without disassembling the mattress itself. This maintenance method differs from solutions where the sensor is permanently sandwiched between the foam or latex layers. Combined with... Figure 5The retractable waterproof sensor core compartment is connected to the signal processing host on the side of the mattress via a mechanical foolproof connector. The sensor core compartment contains a PVDF piezoelectric film physiological sensor array, a reference disturbance acquisition area, a humidity indicator electrode, and a unique EEPROM identification terminal. The signal processing host on the side of the mattress performs mechanical calibration and electrical testing through the sensor core compartment's self-test calibration module, and outputs the hardware reliability status through the clinical deployment interface unit.

[0098] (5) Reference disturbance cancellation. When the bed frame is subjected to external impact at night, the reference disturbance acquisition area first acquires the common-mode vibration of the bed frame, and at the same time, a small-amplitude disturbance residue appears in the main chest cavity acquisition area. The side host uses the reference disturbance channel as the reference signal and adopts adaptive filtering or analog differential cancellation to reduce the common-mode disturbance in the chest cavity channel; if the residual ratio is still higher than the threshold, the time period is marked as a low-confidence segment and is not directly used for vital sign output.

[0099] (6) Sensor Core Self-Check and Aging Compensation. After the mattress is first powered on each day, the sensor core is reinserted, or after disinfection and maintenance, the system first confirms that the mattress is in an off-bed state using a low-resolution body pressure positioning matrix. The side host controls the mechanical calibration excitation unit to output three sets of low-amplitude mechanical excitations at 8Hz, 12Hz, and 18Hz. After each channel of the PVDF array collects the response, it calculates the channel gain G_c, phase delay φ_c, and noise floor N_c, and compares them with the factory calibration parameters stored in the sensor core's EEPROM. At the same time, the electrical test unit inputs test pulses to the PVDF channels, connectors, and pre-charge amplifier circuit to determine whether there is an open circuit, short circuit, or poor contact. If the G_c of a certain channel drops by more than 30%, the N_c increases by more than 6dB, or the electrical test results are abnormal, the system will add that channel to the low-reliability channel list. During dynamic activation, adjacent channels will be enabled first and the amplifier gain will be reconfigured to avoid the failure of the entire bed monitoring due to the aging of a single sensor or abnormal connection.

[0100] (7) Multi-bed deployment in hospital wards. A rehabilitation ward deploys 20 mattresses simultaneously. Each mattress's side unit binds the bed number, patient ID, device number, and unique sensor core compartment identification code through a clinical deployment interface unit. The nurse station receives the online status, bed-off status, continuous pressure points, effective PVDF channel ratio, reference disturbance residual ratio, and sensor core compartment maintenance status for each bed. When a patient experiences continuous pressure on their sacrum and coccyx for more than 2 hours and no effective turning occurs via PVDF body movement signals, the mattress generates a hardware-level continuous pressure event and a reliability level, which the nursing system uses to further generate a turning task. When the sensor core compartment humidity indicator electrode is triggered, the system simultaneously outputs a cleaning or replacement prompt. The outputs in this embodiment are all hardware reliability status or basic nursing event information and do not constitute a disease diagnosis conclusion.

[0101] (8) Protection against cleaning fluid intrusion. When the mattress is used in elderly care facilities, caregivers wipe the skin-friendly covering layer and the outer surface of the sensor core with 75% alcohol. If a small amount of cleaning fluid flows near the side interface, the labyrinth-style drainage channel directs the liquid to the outside of the mattress for drainage, and the dry and wet isolation compartment prevents the liquid from entering the PVDF signal cavity; if the humidity indicator electrode detects abnormal conduction, the side host stops outputting vital signs, retaining only the bed leaving and maintenance prompts. This process is suitable for the repeated disinfection requirements of medical care scenarios and is different from structures where the sensor is fixedly clamped inside the mattress, making it difficult to determine the moisture status.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A structural-level mechanical decoupling mattress for cardiac impact imaging acquisition, characterized in that, It includes a signal processing host on the side of the mattress, and a covering and cushioning layer, a dual-modal mechanical decoupling core layer, a retractable waterproof sensing core, a low-resolution body pressure positioning matrix, and a base layer stacked from top to bottom along the thickness of the mattress. The dual-modal mechanical decoupling core layer includes an elastic bearing matrix, a flexible microbridge conduction sublayer, a shear damping groove sublayer, a lateral energy dissipation cavity sublayer, and an adjustable air pressure microcavity array sublayer, which are used to form a first mechanical channel for conducting low-amplitude vertical micro-vibrations of the heartbeat and a second mechanical channel for conducting high-amplitude disturbance vibrations generated by turning over, bed frame vibration, or limb movement. The retractable waterproof sensing core is equipped with a PVDF piezoelectric film physiological sensing array consisting of several PVDF units and several reference perturbation sensing units. The PVDF units and the reference perturbation sensing units use the same or frequency-matched PVDF piezoelectric film sensors, and each PVDF unit can be independently selected. The PVDF units are used to collect low-amplitude vertical micro-vibrations of the heartbeat transmitted through the first mechanical channel, and the reference perturbation sensing units are used to collect high-amplitude perturbation vibrations transmitted through the second mechanical channel. The low-resolution body pressure positioning matrix is ​​used to collect body pressure sequences. The mattress side signal processing host controls the gating of the PVDF unit, the gain of the PVDF unit's preamplifier, and the mechanical coupling stiffness of the dual-mode mechanical decoupling core layer according to the body pressure sequence, and performs common-mode disturbance cancellation on the output of the gating PVDF unit according to the output of the reference disturbance sensing unit.

2. The structural-level mechanical decoupling mattress for cardiac impact mapping as described in claim 1, characterized in that, The elastic bearing substrate is located between the covering buffer layer and the removable waterproof sensing core chamber, with the side closer to the covering buffer layer as the upper side and the side closer to the removable waterproof sensing core chamber as the lower side. The flexible microbridge conduction sublayer is disposed on the upper surface of the elastic bearing substrate, the shear damping groove sublayer is formed inside the elastic bearing substrate, the lateral energy dissipation cavity sublayer is formed on the side edge of the elastic bearing substrate, and the adjustable air pressure microcavity array sublayer is disposed between the lower surface of the elastic bearing substrate and the upper wall of the removable waterproof sensing core chamber. The flexible microbridge conductive sublayer includes multiple microbridge conductive units arranged in an array within the thoracic projection candidate area of ​​the elastic support substrate. Each microbridge conductive unit protrudes from the upper surface of the elastic support substrate toward the covering buffer layer and is integrally formed with the elastic support substrate by silicone, thermoplastic elastomer or low-hardness polyurethane, or fixed to the upper surface of the elastic support substrate by hot pressing, bonding or embedding. The shear damping groove sublayer includes a number of shear damping grooves formed inside the elastic bearing matrix and located between adjacent microbridge conduction units. The shear damping grooves are grooves that extend along the width direction of the mattress or obliquely to the side edge of the elastic bearing matrix and are staggered with the microbridge conduction units. The lateral energy dissipation cavity layer includes a cavity formed on the side edge of the elastic bearing substrate and connected to the end of one or more shear damping grooves; the end of the groove refers to the end of the shear damping groove that extends from the candidate area of ​​the thoracic cavity projection towards the width of the mattress or obliquely and reaches the side edge of the elastic bearing substrate; the cavity extends along the side edge of the elastic bearing substrate and receives the lateral shear vibrations derived from the shear damping grooves at the connection point, and the cavity is filled with viscoelastic damping material; The adjustable pneumatic microcavity array sublayer is used to adjust the mechanical coupling stiffness of the dual-modal mechanical decoupling core layer. It includes multiple pneumatic microcavity units surrounded by a flexible sealing membrane and a supporting substrate. Each pneumatic microcavity unit is independently or partitioned and connected to the air manifold, micro air pump and valve group. The first mechanical channel passes through the microbridge conduction unit and the pneumatic microcavity unit in sequence, and the second mechanical channel passes through the shear damping groove and the lateral energy dissipation cavity in sequence.

3. The structural-level mechanical decoupling mattress for cardiac impact mapping as described in claim 1, characterized in that, The PVDF piezoelectric thin film physiological sensing array includes a main chest cavity acquisition area, a neck and shoulder auxiliary acquisition area, an abdominal and lumbar body motion acquisition area, and a reference perturbation acquisition area. The main chest cavity acquisition area is a fixed hardware area pre-arranged in the center of the sensing core to cover the chest cavity position of different body types. The chest cavity projection area output by the low-resolution body pressure positioning matrix is ​​a sub-region dynamically calculated based on the current body pressure sequence. The chest cavity projection area is mapped onto the main chest cavity acquisition area and its adjacent neck and shoulder auxiliary acquisition area or abdominal and lumbar body motion acquisition area to determine the PVDF unit to be selected. The neck and shoulder auxiliary acquisition area is used to supplement the acquisition when the chest cavity projection area shifts towards the head of the bed; the abdominal and lumbar body movement acquisition area is used to detect abdominal breathing, turning over, and body movement; the reference disturbance acquisition area consists of one or more reference disturbance sensing units, which are PVDF piezoelectric film sensors that are the same as or have the same frequency response as the PVDF unit, and are set in non-chest cavity pressure-bearing areas or near the lateral discharge end of the lateral energy dissipation chamber, and are used to acquire bed frame vibration, turning over vibration, and environmental common-mode disturbances instead of directly serving as the cardiac impact map output channel.

4. The structural-level mechanical decoupling mattress for cardiac impact mapping as described in claim 1, characterized in that, The body pressure sequence includes the pressure values, valid status of the sampling points, and off-bed status of each pressure sampling point arranged according to the sampling time.

5. The structural-level mechanical decoupling mattress for cardiac impact mapping as described in claim 2, characterized in that, It also includes a sensor activation control module, which comprises a body pressure sequence receiving unit, a parameter calculation unit, a body shape and sleeping posture determination unit, a chest cavity projection positioning unit, and a control output unit. The parameter calculation unit calculates the pressure centroid, effective body pressure area, pressure distribution length, and local pressure change rate based on the body pressure sequence acquired by the low-resolution body pressure positioning matrix. The body shape and sleeping posture determination unit determines the body shape pattern and sleeping posture based on the parameters. The chest cavity projection positioning unit determines the chest cavity projection area based on the pressure center of gravity, effective body pressure area, pressure distribution length, and body shape pattern. The control output unit outputs the PVDF unit gating combination, preamplifier gain, and target air pressure of the adjustable air pressure microcavity array sublayer according to body shape pattern, sleeping posture, and chest cavity projection area.

6. The structural-level mechanical decoupling mattress for cardiac impact mapping as described in claim 1, characterized in that, It also includes a sensor core self-test calibration module, which includes a mechanical calibration excitation unit, an electrical testing unit, a channel response calculation unit, and a fault bypass unit. The mechanical calibration excitation unit is used to input a mechanical calibration signal with known frequency and amplitude, and the electrical test unit is used to input test pulses to the PVDF sensor array, connector and preamplifier circuit to detect open circuit, short circuit, poor contact or abnormal front-end circuit. The channel response calculation unit calculates the mechanical channel health coefficient H_mech based on the mechanical calibration response and the electrical channel health coefficient H_elec based on the electrical test response. When H_mech or H_elec is below the unavailable threshold, the fault bypass unit removes the corresponding PVDF unit from the selection candidate list. When H_mech and H_elec are between the unavailable threshold and the normal threshold, the channel fusion coefficient of the PVDF unit in the multi-channel BCG weighted fusion is reduced. The multi-channel BCG weighted fusion refers to performing reference disturbance cancellation and heartbeat band filtering on the outputs of multiple PVDF units that have not been removed in sequence, and then performing weighted summation according to the normalized channel fusion coefficient to obtain the fused BCG waveform. The channel fusion coefficient is jointly determined by the mechanical channel health coefficient, electrical channel health coefficient and signal quality coefficient of the corresponding channel.

7. A method of using a structural-level mechanical decoupling mattress for cardiac impact mapping, based on the structural-level mechanical decoupling mattress for cardiac impact mapping as described in any one of claims 1 to 6, characterized in that, include: Collect body pressure sequences and calculate body shape patterns, sleeping positions, and chest projection areas; The target air pressure of the adjustable air pressure microcavity array sublayer is set according to the body shape pattern; The PVDF unit gating combination is determined based on body shape pattern, sleeping posture, and chest projection area, and the preamplifier gain is configured accordingly. Using the output of the reference disturbance sensing unit as a reference, common-mode disturbance cancellation is performed on the output of the gating PVDF unit; Calculate the peak-to-noise ratio SNR_ch, J-wave template correlation coefficient r_J, and reference perturbation residual ratio E_ref for each gated channel. SNR_ch is used to characterize the amplitude quality of the J-wave candidate peak relative to the noise floor, r_J is used to characterize the consistency between the current cardiac impact map morphology and the J-wave template, and E_ref is used to characterize the residual degree of reference perturbation energy after perturbation cancellation. Channels that simultaneously meet the following criteria and are not marked as faulty are identified as valid channels: SNR_ch is not lower than the peak-to-noise ratio threshold, r_J is not lower than the correlation threshold, E_ref is not higher than the residual threshold, and the channel is not marked as faulty. The ratio of the number of valid channels to the number of selected channels is used as the effective signal ratio. When the effective signal ratio is not lower than the ratio threshold, the signal output of the valid channel after disturbance cancellation and cardiac impaction band filtering is the valid BCG signal segment. When the effective signal ratio is lower than the ratio threshold, the adjacent PVDF unit is expanded and activated and re-evaluated.

8. The method of using the structural-level mechanical decoupling mattress for cardiac impact mapping as described in claim 7, characterized in that, The calculation of body shape pattern, sleeping posture, and chest projection area includes the following steps: The low-resolution body pressure positioning matrix collects the body pressure sequence of each pressure sampling point over time and sends it to the sensor activation control module; The sensor activation control module calculates the pressure centroid, effective body pressure area, pressure distribution length, and local pressure change rate based on the body pressure sequence. Body type patterns for children, standard adults, or large adults are determined based on effective body pressure area and pressure distribution length. The supine, left lateral, right lateral, or off-bed position is determined based on the lateral offset of the center of gravity and the rate of pressure change in the left and right local areas. The thoracic projection area is determined based on the pressure center of gravity, pressure distribution length, and body shape pattern.

9. The method of using the structural-level mechanical decoupling mattress for cardiac impact mapping as described in claim 7, characterized in that, The step of setting the target air pressure of the adjustable air pressure microcavity array sublayer according to the body shape pattern includes: In standard adult mode, the target air pressure of the adjustable pressure microcavity array sublayer is set to the standard reference air pressure P_std, which is 100kPa to 130kPa. In child mode, the target air pressure is set to 65% to 80% of P_std. In large adult mode, the target air pressure is set to 110% to 120% of P_std. In each mode, the target air pressure is finely adjusted in a closed loop according to whether the amplitude of the effective BCG signal segment is lower than the noise threshold or higher than the saturation threshold.

10. The method of using the structural-level mechanical decoupling mattress for cardiac impact mapping as described in claim 7, characterized in that, The process of determining the PVDF unit gating combination and configuring the preamplifier gain based on body shape pattern, sleeping posture, and chest projection area includes: In the standard adult supine mode, activate 3×4 PVDF units in the main acquisition area of ​​the chest cavity that overlap with the chest cavity projection area, and configure the standard gain G_std and the standard ADC reference voltage. In child mode, activate the 2×3 PVDF units in the center of the main chest cavity acquisition area, configure the preamplifier gain to 2 to 4 times G_std, and switch the ADC reference voltage to ±0.3V; In the large adult mode, activate the entire array of the main chest cavity acquisition area and adjacent auxiliary columns; In left or right lateral decubitus mode, the PVDF column on the side with the offset of the pressure center of gravity is activated first, and when the effective signal ratio on that side is insufficient, it is extended to the adjacent column.

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