Intelligent sports ground mat electrical response test method and system

Abstract

The application relates to the technical field of product testing, in particular to a method and system for testing the electrical response of an intelligent sports floor mat. The method comprises continuously applying oblique shear stress to the sports floor mat within a test period, obtaining an X-ray perspective image set of the sports floor mat within the test period, and determining a compression gradient set covering a stress-affected area by using the X-ray perspective image set; obtaining a voltage signal set of the grid nodes of the sports floor mat within the test period, determining extreme value nodes from the voltage signal set, taking the extreme value nodes as reference starting points, determining an attenuation gradient set covering the stress-affected area based on the voltage drop characteristics between a plurality of target nodes distributed along the projection direction of the shear stress extension in turn, and determining the electrical response test result of the sports floor mat by using the compression gradient set and the attenuation gradient set. Through the technical scheme, the electrical response test of the intelligent sports floor mat can be more accurately realized.

Description

Technical Field

[0001] This application relates to the field of product testing technology, and in particular to a method and system for testing the electrical response of intelligent sports mats. Background Technology

[0002] The intelligent sports mat is a multi-layered composite sensing structure, mainly composed of a surface anti-slip and wear-resistant fabric, a horizontal and vertical cross electrode array, a sensing layer, and a cushioning and shock-absorbing bottom layer; it is equipped with a signal conditioning circuit board, a main control processing unit, a wireless communication module, and a power supply component; when the mat is subjected to stepping pressure, the electrical parameters of the sensing layer change, the electrode array collects the point electrical signal, and after circuit filtering and analog-to-digital conversion, the main control calculates the motion data such as the stepping position and pressure magnitude.

[0003] Intelligent sports mats can automatically complete standing long jump distance measurement, jump counting, and foul judgment in campus physical fitness tests. Professional sports teams can use intelligent sports mats to collect data on push-off force and landing trajectory to assist in the correction of movement techniques. Related technologies often use standard vertical loading devices to apply normal static or dynamic loads to specific areas of the mat. For example, Chinese invention patent with authorization announcement number CN115585913B discloses a flexible shear stress sensor, which uses a five-mode metamaterial to construct a flexible shear stress sensing unit and achieves shear force detection through coupling of normal and tangential forces. Related technologies can use this flexible shear stress sensor to calibrate the correspondence between pressure and electrical signal using vertical or unidirectional loading methods to achieve response detection of single points or local areas.

[0004] However, in real sports competition scenarios, athletes' sudden stops, changes of direction, and jump landings will generate oblique impacts on the surface of the mat, causing the internal structure of the mat to bear complex shear stress. Vertical static or dynamic loading methods cannot simulate the internal deformation state of the mat under oblique shear stress, making it difficult to accurately test the electrical response of smart sports mats. Summary of the Invention

[0005] To more accurately test the electrical response of smart sports mats, this application provides a method and system for testing the electrical response of smart sports mats.

[0006] According to a first aspect of the embodiments of this application, a method for testing the electrical response of an intelligent sports mat is provided, comprising: continuously applying oblique shear stress to the sports mat during a test period; acquiring an X-ray imaging set of the sports mat during the test period; and using the X-ray imaging set to determine a set of compression gradients covering the stress-affected area; the set of compression gradients includes multiple thickness change rates; acquiring a set of voltage signals of the grid nodes of the sports mat during the test period; determining extreme nodes from the voltage signal set; and using the extreme nodes as reference starting points to acquire voltage drop characteristics between multiple target nodes sequentially distributed along the shear stress extension projection direction. The attenuation gradient set covering the stress-affected area is determined based on voltage drop characteristics; the attenuation gradient set includes multiple voltage drop rates; the contact origin generated when oblique shear stress is applied to the sports mat is determined, and a reference coordinate system is constructed with the contact origin as a reference; the compression gradient set and the attenuation gradient set are projected and aligned into the reference coordinate system to obtain a spatial mapping matrix; based on the thickness change rate and voltage drop rate associated with the spatial nodes of the spatial mapping matrix, the dynamic electromechanical coupling ratio of the spatial nodes is determined; based on the dynamic electromechanical coupling ratio of multiple consecutive spatial nodes, the electrical response test results of the sports mat under shear stress are determined.

[0007] In this way, the deformation characteristics of the sports mat determined by the X-ray imaging set can be combined with the electrical response characteristics determined by the voltage signal set of the grid nodes of the sports mat during the test period, so as to more accurately realize the electrical response test of the smart sports mat.

[0008] Optionally, the compression gradient set is determined using an X-ray fluoroscopic image set, including: determining a target image representing the extreme shear depth from the X-ray fluoroscopic image set; determining the grayscale abrupt change rate between each adjacent pixel in the target image; identifying the density junction edge between the sensor array layer and the internal buffer layer in the target image based on the grayscale abrupt change rate; extracting the top surface contour line and the bottom surface contour line based on the geometric contour trajectory of the density junction edge; and determining the compression gradient set based on the top surface contour line and the bottom surface contour line.

[0009] Optionally, the compression gradient set is determined based on the top and bottom contour lines, including: taking the shear extension direction when oblique shear stress is applied as the horizontal reference axis, and determining multiple discrete acquisition points on the horizontal reference axis; for each acquisition point, determining the orthogonal distance between the top and bottom contour lines perpendicular to the horizontal reference axis, and taking the orthogonal distance as the corresponding spatial thickness; determining the thickness change rate corresponding to each acquisition point based on the thickness difference between the spatial thicknesses corresponding to adjacent acquisition points, combined with the spacing span between adjacent acquisition points; extracting the position coordinates of each acquisition point on the horizontal reference axis; and sorting the thickness change rates corresponding to each acquisition point based on the arrangement order of the position coordinates to obtain the compression gradient set.

[0010] Optionally, the voltage drop characteristics among multiple target nodes distributed sequentially along the shear stress extension projection direction are obtained, and the attenuation gradient set covering the stress-affected area is determined based on the voltage drop characteristics. This includes: sequentially reading the voltage values ​​of each spatially adjacent target node along the shear stress extension projection direction, determining the voltage difference between adjacent target nodes, and determining the voltage drop rate corresponding to each target node by combining the wiring spacing of the sensing grid with the voltage difference; extracting the position coordinates of each target node relative to the spatial reference starting point along the shear stress extension projection direction, and sequentially arranging the voltage drop rates corresponding to each target node based on the arrangement order of the position coordinates to obtain the attenuation gradient set.

[0011] In this way, by extracting the potential difference between nodes along the projection vector direction of shear stress on the horizontal plane and solving the voltage drop rate in combination with the grid wiring spacing, it is possible to sense the trend of electrical performance degradation of flexible electrode materials under torn or overstretched edge conditions.

[0012] Optionally, the compression gradient set and the attenuation gradient set are projected and aligned into the reference coordinate system to obtain a spatial mapping matrix. This includes: using a pre-calibrated scaling parameter, projecting the coordinates of the acquisition points corresponding to the thickness change rate contained in the compression gradient set onto the reference horizontal axis starting from the contact origin; converting the arrangement coordinates of the internal grid nodes into geometric coordinates from the contact origin; and binding and associating the thickness change rate and voltage drop rate with the same geometric coordinates in the reference coordinate system to obtain a spatial mapping matrix with a common data recording dimension.

[0013] Optionally, the dynamic electromechanical coupling ratio of a spatial node is determined based on the thickness change rate and voltage drop rate associated with the spatial node in the spatial mapping matrix. This includes: traversing and locating spatial nodes in the spatial mapping matrix, extracting the thickness change rate and voltage drop rate associated with the spatial node in the same data record dimension, and using the ratio of the voltage drop rate to the thickness change rate as the dynamic electromechanical coupling ratio of the spatial node.

[0014] In this way, by performing ratio calculations on the mechanical compression parameters and electrical loss parameters at the same spatial node under the same reference coordinate system, the synchronization and coordination between the elastic body deformation and the conductive network can be determined based on the degree of linear or nonlinear deviation of the ratio.

[0015] Optionally, the electrical response test results of the sports mat under shear stress are determined based on the dynamic electromechanical coupling ratios of multiple consecutive spatial nodes, including: reading the dynamic electromechanical coupling ratio of each spatial node and comparing whether the dynamic electromechanical coupling ratio of each spatial node falls within a preset standard range; if the dynamic electromechanical coupling ratio falls within the preset standard range, the corresponding spatial node is determined as a normal node; or, if the dynamic electromechanical coupling ratio does not fall within the preset standard range, the corresponding spatial node is determined as an abnormal node; the electrical response test results of the sports mat under shear stress are determined based on the distribution of normal and abnormal nodes.

[0016] Optionally, based on the distribution of normal and abnormal nodes, the electrical response test results of the sports mat under shear stress are determined, including: counting the number of consecutive distributions of abnormal nodes along the shear extension direction and the deviation span corresponding to each abnormal node; if the number of consecutive distributions is greater than a preset threshold, it is determined that there is a misalignment in the internal sensing medium of the sports mat; extracting the number of consecutive distributions and the deviation span to construct a defect test report for the misalignment state, and outputting electrical test results characterizing the sports mat as unqualified based on the defect test report.

[0017] In this way, by analyzing the connectivity characteristics and deviation of abnormal nodes in the spatial domain and setting a quantity threshold, sporadic false alarms caused by environmental noise can be filtered out, and more accurate defect test reports can be generated.

[0018] Optionally, acquiring the voltage signal set of the grid nodes during the applied oblique shear stress period includes: acquiring the feedback signal generated after transmitting a detection signal to the edge encapsulation area of ​​the sports mat, determining the acoustic attenuation rate and phase delay between the feedback signal and the detection signal; determining a compensation coefficient based on the acoustic attenuation rate and phase delay, and performing baseline zeroing calibration on the acquired initial voltage readings using the compensation coefficient before acquiring the voltage signal set of the grid nodes during the applied oblique shear stress period, thereby obtaining the voltage signal set after baseline zeroing calibration.

[0019] Optionally, the compensation coefficient is determined based on the acoustic wave attenuation rate and the phase delay, including: calling a pre-built dielectric constant drift mapping table; the dielectric constant drift mapping table contains dielectric constant drift values ​​corresponding to different combinations of acoustic wave attenuation rate and phase delay; inputting the acoustic wave attenuation rate and phase delay into the dielectric constant drift mapping table to perform an association search to determine the target drift value; determining the parasitic capacitance increment caused by environmental moisture adhesion based on the target drift value, and determining the corresponding compensation coefficient based on the parasitic capacitance increment.

[0020] In this way, the dielectric constant drift can be inferred by reverse deducing the attenuation and phase shift characteristics of water molecules when sound waves propagate at the material boundary. This allows us to avoid stray parasitic capacitance interference introduced by changes in temperature and humidity of the test environment before performing core tests, thus ensuring the consistency between the signal-to-noise ratio of the dynamic signal set and the test results.

[0021] According to a second aspect of the present application, an intelligent sports mat electrical response testing system is provided, comprising: a processor and a memory, wherein the memory stores computer program instructions, and the computer program instructions, when executed by the processor, implement the steps of the intelligent sports mat electrical response testing method provided in the first aspect of the present application.

[0022] The technical solutions provided by the embodiments of this application may include the following beneficial effects: continuously applying oblique shear stress to the sports mat during the test period, reflecting the deformation of the internal structure of the smart sports mat under shear stress through X-ray imaging, and obtaining the voltage signal set of the grid nodes of the smart sports mat during the test period, it is possible to determine the dynamic correspondence between the compression gradient of the local material of the smart sports mat and the attenuation gradient of the electrical signal, so as to evaluate the electrical response performance of the sensing medium under asymmetric deformation state based on the dynamic electromechanical coupling ratio, and more accurately realize the electrical response test of the smart sports mat.

[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating an electrical response testing method for a smart sports mat according to an exemplary embodiment; Figure 2 A schematic diagram showing the distribution of the electromechanical coupling ratio of the smart sports mat to be tested; Figure 3 This is a schematic diagram of the structure of an intelligent sports mat electrical response testing system according to an exemplary embodiment. Detailed Implementation

[0025] To more accurately test the electrical response of smart sports mats, this application provides a method and system for testing the electrical response of smart sports mats. Figure 1 This is a flowchart illustrating an electrical response testing method for a smart sports mat according to an exemplary embodiment, such as... Figure 1 As shown, the method includes the following steps.

[0026] In step S101, the set of compression gradients of the sports mat is obtained during the test period.

[0027] During the test period, oblique shear stress was continuously applied to the sports mat, and a set of X-ray images of the sports mat during the test period was obtained. The set of compression gradients covering the stress-affected area was then determined using the set of X-ray images.

[0028] During the initialization and loading execution phase of the test cycle, a continuous oblique shear stress with a predetermined angle can be applied to the sports mat laid on the rigid bearing platform by a servo multi-axis actuator to simulate the friction and non-orthogonal impact of athletes during a sudden stop in a competition.

[0029] Because the stress on the contact surface is decomposed into a normal component that compresses the mat material along the thickness direction and a tangential component that causes the mat surface material to slide parallel to the base, the polyurethane foam buffer layer inside the mat and the embedded flexible polyimide sensing grid produce an asymmetric structural distortion.

[0030] By using X-ray generators and flat panel detector arrays positioned directly above and below the mat, a set of X-ray images of the smart sports mat under test can be obtained during the test period. The set of X-ray images can reflect the internal energy distribution of the smart sports mat, as well as the internal pore collapse and interlayer compression state. By solving the geometric gradient for the pixels in the affected stress area, a set of compression gradients can be obtained, consisting of a sequence of thickness change rates that characterize the degree of deformation.

[0031] In one embodiment, determining the compression gradient set using an X-ray fluoroscopic image set includes: determining a target image representing the extreme shear depth from the X-ray fluoroscopic image set; determining the grayscale abrupt change rate between adjacent pixels in the target image; identifying the density junction edge between the sensor array layer and the internal buffer layer in the target image based on the grayscale abrupt change rate; extracting the top surface contour line and the bottom surface contour line based on the geometric contour trajectory of the density junction edge; and determining the compression gradient set based on the top surface contour line and the bottom surface contour line.

[0032] In the process of analyzing a set of X-ray fluoroscopic images acquired at high frequency, the target image reflecting the compression of the interior of the ground mat to its limit can be determined by traversing the global histogram features of the image sequence and determining the spatial expansion extrema of low grayscale pixel clusters.

[0033] When X-ray photons penetrate the sensing array layer woven from high-density conductive metal wires and the internal buffer layer composed of low-density porous polymer, photoelectric absorption and Compton scattering effects occur, causing a significant change in photon transmittance at the material property boundary of the target image, which is mapped as oscillations in grayscale readings between adjacent pixel arrays.

[0034] In the pixel space of the image, a two-dimensional difference operator is used to calculate the gray level difference between adjacent pixels along the bidirectional orthogonal gradient direction of rows and columns and then normalize it to obtain the gray level mutation rate that reflects the intensity of material mutation. Pixels with gray level mutation rates exceeding the preset mutation rate threshold are marked with connected components and morphological closing operations in a two-dimensional matrix, thereby outlining continuous and closed density junction edges in the target image to characterize the extrusion boundary morphology of different medium layers under shear stress.

[0035] Since the junction edge completely encloses the entire compressed and deformed buffer cavity on a macroscopic level, and its geometric contour trajectory records the distortion state of the force-bearing surface and the support surface, the density junction edge can be peeled and decomposed into the top surface contour line representing the sinking trend of the force-bearing surface and the bottom surface contour line representing the support state of the bottom reaction force through the contour tracking algorithm in the polar coordinate system. This eliminates the interference of the edge region for subsequent calculation of the thickness compression index.

[0036] In one embodiment, determining the compression gradient set based on the top and bottom contour lines includes: using the shear extension direction when oblique shear stress is applied as a horizontal reference axis, and determining multiple discrete acquisition points on the horizontal reference axis; for each acquisition point, determining the orthogonal distance between the top and bottom contour lines perpendicular to the horizontal reference axis, and using the orthogonal distance as the corresponding spatial thickness; determining the thickness change rate corresponding to each acquisition point based on the thickness difference between the spatial thicknesses corresponding to adjacent acquisition points, combined with the spacing span between adjacent acquisition points; extracting the position coordinates of each acquisition point on the horizontal reference axis; and sorting the thickness change rates corresponding to each acquisition point based on the arrangement order of the position coordinates to obtain the compression gradient set.

[0037] By defining the vector projection direction of the oblique shear stress applied by the servo actuator onto the surface of the two-dimensional test platform as the horizontal reference axis of the global system, and since the continuously distributed contour lines contain redundant geometric details, multiple discrete acquisition points are equally spaced on the horizontal reference axis with sampling intervals, thus completing the discretization and dimensionality reduction processing of the continuous geometric space.

[0038] For each acquisition point, spatial intersections with the top and bottom contour lines can be obtained along the normal direction perpendicular to the horizontal reference axis, and the Euclidean distance between the two intersection points can be calculated. The orthogonal distance, which includes the dual effects of normal compression and tangential misalignment, is used as the spatial thickness at the discrete coordinates.

[0039] Considering the continuous law of stress transmission within the material, the spatial thickness associated with adjacent sampling points can be extracted and subtracted to obtain the thickness difference that characterizes the gradual extrusion trend of the material. The thickness difference is then combined with the spacing span determined by the discretization process to determine the thickness change rate. The compression gradient set contains multiple thickness change rates.

[0040] The thickness change rate can be determined, for example, in the following way: ,in, This represents the rate of change of thickness corresponding to the sampling point. This represents the thickness difference between adjacent sampling points. This indicates the distance between adjacent data collection points.

[0041] After solving the ratio of local nodes, the absolute position coordinates of each acquisition point relative to the origin on the constructed horizontal reference axis can be extracted one by one. Then, according to the arrangement order of increasing coordinate values, the scattered thickness change rates are spliced ​​and merged into a compressed gradient set with one-dimensional spatial sequence properties.

[0042] In step S102, the attenuation gradient set of the force-affected area of ​​the sports mat is obtained.

[0043] The voltage signal set of the grid nodes of the sports mat during the test period is obtained. The extreme nodes are determined from the voltage signal set. Using the extreme nodes as the reference starting point, the voltage drop characteristics between multiple target nodes distributed sequentially along the shear stress extension projection direction are obtained. Based on the voltage drop characteristics, the attenuation gradient set covering the stress-affected area is determined.

[0044] When the interwoven grid nodes inside the sports mat are subjected to strain, the contact resistance and interlayer parasitic capacitance of its micro-conductive filler will fluctuate dynamically and nonlinearly. By scanning through each grid node and using an analog-to-digital converter to convert the analog level into a voltage signal set containing timestamps and position indices, the extreme node with the highest voltage attenuation amplitude and located at the center of the deformation vortex can be identified as the core anchor point for analysis through the derivative extreme value search algorithm.

[0045] The attenuation gradient set contains multiple voltage drop rates. It extends along the tangential component of the oblique shear stress on the two-dimensional horizontal topological surface, extracts the absolute voltage drop between adjacent target nodes point by point, and combines the distance between the nodes to normalize the voltage drop rate to form the attenuation gradient set.

[0046] In one embodiment, obtaining the voltage drop characteristics among multiple target nodes sequentially distributed along the shear stress extension projection direction, and determining the attenuation gradient set covering the stress-affected area based on the voltage drop characteristics, includes: sequentially reading the voltage values ​​of each spatially adjacent target node along the shear stress extension projection direction, determining the voltage difference between adjacent target nodes, and determining the voltage drop rate corresponding to each target node by combining the wiring spacing of the sensing grid with the voltage difference; extracting the position coordinates of each target node relative to the spatial reference starting point along the shear stress extension projection direction, and sequentially arranging the voltage drop rates corresponding to each target node based on the arrangement order of the position coordinates to obtain the attenuation gradient set.

[0047] In the dynamic tracking and gradient analysis of the electrical parameters at the bottom layer of the sensing grid, the pre-determined shear stress extension projection direction is used as the main axis for scanning addressing. This allows crosstalk signals that are unrelated to the main force direction to be filtered out, thereby determining the path that can reflect electrical strain.

[0048] By sequentially reading the real-time dynamic voltage values ​​of each target node distributed on a one-dimensional projection trajectory excited by a high-frequency excitation source, and calculating the voltage difference between adjacent nodes within the same specific sampling time window, it is possible to derive the core parameter voltage drop rate, which characterizes the rate of degradation of electrical conduction efficiency, by using an index that can characterize the potential loss per unit spatial distance, and by calling the pre-calibrated mesh wiring size between adjacent nodes and performing coupled calculations with the extracted absolute voltage difference.

[0049] Voltage sag rate can be determined, for example, in the following way: ,in, This represents the voltage drop rate corresponding to the target node. This represents the voltage difference between adjacent target nodes. This indicates the wiring spacing of the sensor grid.

[0050] After completing the single-point parameter calculation, in order to construct a gradient dataset with spatial continuity representation capabilities, the absolute position coordinates of each target node in the test plane coordinate system relative to the preset spatial reference starting point in the extension direction can be extracted one by one. Then, the position coordinates are used as indexes to perform continuous permutation and combination of the voltage drop rate data of each target node scattered in memory, generating a set of attenuation gradients that completely covers the entire tensile region.

[0051] In step S103, the spatial mapping matrix of the sports mat is determined.

[0052] The contact origin is determined when oblique shear stress is applied to the sports mat. A reference coordinate system is constructed with the contact origin as a reference. The compression gradient set and the attenuation gradient set are projected and aligned into the reference coordinate system to obtain the spatial mapping matrix.

[0053] The contact origin captured by the initial force sensor array can be used as the absolute zero point to establish a unified Euclidean reference coordinate system. Then, the set of compression gradients containing the optical deformation dimension and the set of attenuation gradients containing the electrical signal loss dimension can be aligned by meshing in three-dimensional space using an affine transformation matrix to generate a fused spatial mapping matrix.

[0054] In one embodiment, the spatial mapping matrix is ​​obtained by projecting and aligning the compression gradient set and the attenuation gradient set into a reference coordinate system. This includes: using a pre-calibrated scaling parameter, projecting the coordinates of the acquisition points corresponding to the thickness change rate contained in the compression gradient set onto a reference horizontal axis starting from the contact origin; converting the arrangement coordinates of the internal grid nodes into geometric coordinates from the contact origin; and binding and associating the thickness change rate and voltage drop rate with the same geometric coordinates in the reference coordinate system to obtain a spatial mapping matrix with a common data recording dimension.

[0055] In the geometric registration and matrix reconstruction process, due to the potential scale differences between the pixel resolution coordinate system of the X-ray detector array and the wiring coordinate system of the flexible printed circuit board laid inside the mat, as well as translational deviations caused by different test fields of view, a scaling parameter pre-generated based on the calibration target mesh can be introduced. This allows the extraction of the acquisition point position coordinates based on the local image dimension associated with each thickness change rate recorded in the compressed gradient set. The scaling parameter is then used to perform a linear scaling product operation, mapping the coordinates to a reference horizontal axis with the contact origin as the absolute zero point and parallel to the direction of force, thereby completing the proportional projection of the optical geometric coordinates.

[0056] For internal grid nodes containing voltage drop rate data in the electrical signal domain, the geometric coordinates of the contact origin are solved by performing translation and rotation matrix transformation operations based on the factory-preset arrangement coordinates in the Cartesian coordinate system and the offset of the contact origin.

[0057] When two sets of data sequences from different monitoring methods are calibrated to the reference coordinate system, a comparison can be performed in the coordinate set through a traversal search algorithm to determine the spatial node poses with completely identical geometric coordinates. The thickness change rate and voltage drop rate corresponding to the node can then be recorded in the same structure pointer for binding association. After traversing and verifying the coordinate points of the entire coverage area, the scattered deformation data and electrical data are fused into a spatial mapping matrix with common data dimensions in the horizontal rows and vertical columns, so that subsequent calculation operations can avoid signal misjudgment failures caused by spatial misalignment.

[0058] In step S104, the electrical response test results of the sports mat are determined.

[0059] Based on the thickness change rate and voltage drop rate associated with the spatial nodes of the spatial mapping matrix, the dynamic electromechanical coupling ratio of the spatial nodes is determined. Based on the dynamic electromechanical coupling ratio of multiple consecutive spatial nodes, the electrical response test results of the sports mat under shear stress are determined.

[0060] Based on the division comparison operation performed on the voltage drop rate and thickness change rate at the same spatial node in the spatial mapping matrix, the dynamic electromechanical coupling ratio reflecting the electrical attenuation sensitivity induced by the unit compression of local materials is determined. Based on the smooth continuity or abrupt oscillation of the ratio on continuous spatial nodes, it can be determined whether the internal structure of the smart sports mat is in benign elastic deformation or has undergone irreversible conductive layer peeling and misalignment.

[0061] In one embodiment, determining the dynamic electromechanical coupling ratio of a spatial node based on the thickness change rate and voltage drop rate associated with the spatial node in the spatial mapping matrix includes: traversing and locating spatial nodes in the spatial mapping matrix, extracting the thickness change rate and voltage drop rate associated with the spatial node in the same data record dimension, and using the ratio of the voltage drop rate to the thickness change rate as the dynamic electromechanical coupling ratio corresponding to the spatial node.

[0062] By traversing the matrix to locate each spatial node containing valid data, since the spatial mapping matrix after pre-projection alignment is presented in memory as a two-dimensional or even high-dimensional floating-point table structure with fixed data record dimensions, the thickness change rate of the associated and bound structural extrusion deformation and the voltage drop rate of the conductive network ohmic loss characteristics can be extracted under the same spatial scale dimension.

[0063] When the floor mat sensing layer is in an ideal elastic working state, the internal silver nanowire or carbon black conductive network is squeezed when subjected to mechanical compression, which leads to an increase in contact points and a decrease in resistance and voltage drop. The extracted two-dimensional parameters with different dimensions can be subjected to ratio calculation based on the division instruction set to obtain an index reflecting the piezoresistive sensitivity characteristics of the material.

[0064] The dynamic electromechanical coupling ratio can be determined, for example, in the following way: ,in, This represents the dynamic electromechanical coupling ratio corresponding to the spatial node. This represents the voltage drop rate associated and bound to spatial nodes within the same data record dimension. This represents the thickness change rate associated with the binding; the voltage drop rate and thickness change rate can be pre-processed to be dimensionless, and then the dimensionless voltage drop rate and thickness change rate can be used in the calculation.

[0065] The calculated quotient is used as the dynamic electromechanical coupling ratio of the spatial node. When the mechanical deformation of the buffer substrate material and the electrical degradation of the conductive film attached to its surface are synchronized and coordinated, the ratio will remain near a constant with small fluctuations. The obtained dynamic electromechanical coupling ratio is used to characterize the electrical response performance of the node, improve the robustness to external environmental interference, and increase the sensitivity to the identification of internal debonding or wire tearing.

[0066] Figure 2 A schematic diagram illustrating the distribution of the electromechanical coupling ratio of the smart sports mat to be tested, as shown below. Figure 2 As shown, the dynamic electromechanical coupling ratio of most spatial nodes is less than the preset upper limit, and these nodes are judged as normal nodes. However, in some spatial geometric coordinate areas, the dynamic electromechanical coupling ratio shows a sudden peak and significantly exceeds the preset upper limit, failing to fall within the preset standard range. These nodes are judged as abnormal nodes. The distribution map can intuitively identify the deviation span and distribution status of abnormal nodes in the spatial domain, thereby providing data support for subsequent determination of whether the sensing medium inside the mat has been misaligned and for generating defect test reports.

[0067] In one embodiment, determining the electrical response test result of the sports mat under shear stress based on the dynamic electromechanical coupling ratio of multiple consecutive spatial nodes includes: reading the dynamic electromechanical coupling ratio of each spatial node and comparing whether the dynamic electromechanical coupling ratio of each spatial node falls within a preset standard range; if the dynamic electromechanical coupling ratio falls within the preset standard range, the corresponding spatial node is identified as a normal node; or, if the dynamic electromechanical coupling ratio does not fall within the preset standard range, the corresponding spatial node is identified as an abnormal node; and determining the electrical response test result of the sports mat under shear stress based on the distribution of normal and abnormal nodes.

[0068] The dynamic electromechanical coupling ratio of nodes in qualified smart sports mat samples can be statistically analyzed in advance to obtain the preset standard range corresponding to normal nodes of smart sports mats. When the dynamic electromechanical coupling ratio calculated for a certain spatial node falls within the preset standard range, it indicates that the mechanical compression gradient in the area where the spatial node is located has successfully triggered the matching resistivity change and the material interlayer interface is firmly adhered. The spatial node can be marked as a normal node in a stable working state.

[0069] Conversely, if the dynamic electromechanical coupling ratio of a spatial node does not fall within the preset standard range, it indicates that the electrical grid of the spatial node may be broken, resulting in an abnormal voltage drop rate or an abnormal thickness change rate due to excessive slippage. This causes the mechanical compression gradient in the area where the spatial node is located to fail to trigger a matching change in resistivity, and the spatial node can be marked as an abnormal node.

[0070] After marking all nodes in the matrix as normal or abnormal, the distribution of healthy normal nodes and damaged abnormal nodes can be determined based on spatial topological graph theory. This allows us to assess whether the abnormality is due to isolated noise caused by sporadic dust particles or the collapse of large sections of material caused by continuous oblique shear tearing. By statistically analyzing the distribution, we can output the electrical response test results of the smart sports mat to indicate whether the smart sports mat as a whole maintains a good electrical response.

[0071] In one embodiment, the electrical response test results of the sports mat under shear stress are determined based on the distribution of normal and abnormal nodes, including: counting the number of consecutive distributions of abnormal nodes along the shear extension direction and the deviation span corresponding to each abnormal node; if the number of consecutive distributions is greater than a preset threshold, it is determined that there is a misalignment in the internal sensing medium of the sports mat; extracting the number of consecutive distributions and the deviation span to construct a defect test report for the misalignment state, and outputting electrical test results characterizing the sports mat as unqualified based on the defect test report.

[0072] Relying solely on isolated identification of anomalous nodes may not meet the requirements of industrial quality traceability. Performing clustering search statistics along the shear extension direction in a specific stress transmission coordinate system can accumulate the number of consecutively distributed anomalous nodes that are connected end to end in the topological location.

[0073] Considering that air bubbles or environmental electromagnetic pulses in the production process can easily generate single or a small number of isolated and discrete abnormal nodes in the test matrix, such occasional noise can be filtered out using a preset number threshold. When the number of consecutive distributions along the stress tearing trajectory is greater than the preset number threshold, it indicates that the accumulation of oblique tangential force has exceeded the interlayer ultimate shear yield strength, resulting in irreversible relative slippage between the internal sensing medium and the outer encapsulation layer of the sports mat.

[0074] To assess the extent of tearing caused by misalignment to the electrical response network, the electromechanical coupling ratio of each marked abnormal node and its Euclidean distance from the center value of a preset standard interval can be determined. The deviation span reflecting the depth of material distortion can be determined. By using the number of continuous distributions representing the extent of damage area and the deviation span representing the depth of damage, a defect test report for misalignment can be constructed. The defect test report can then be pushed to the upper-level user terminal or production management interface, outputting test results that include specific failure coordinates, failure area, and characterization of the sports mat's non-compliance.

[0075] By simultaneously utilizing spatial continuity statistics and absolute value of parameter deviation, it helps reduce the false alarm rate of testing equipment in complex electromagnetic environments, making the output scrap judgment results more reliable and avoiding misjudging qualified products that do not actually have any abnormalities as unqualified products.

[0076] In one embodiment, acquiring the voltage signal set of grid nodes during the applied oblique shear stress period includes: acquiring the feedback signal generated after transmitting a probe signal to the edge encapsulation area of ​​the sports mat; determining the acoustic attenuation rate and phase delay between the feedback signal and the probe signal; determining a compensation coefficient based on the acoustic attenuation rate and phase delay; and performing baseline zeroing calibration on the acquired initial voltage reading using the compensation coefficient before acquiring the voltage signal set of grid nodes during the applied oblique shear stress period to obtain the voltage signal set after baseline zeroing calibration.

[0077] When sports mats are deployed in complex venue environments involving water vapor evaporation or alternating air humidity, water molecules can penetrate into the polyurethane edge gaps of the mat and adhere to the insulating medium surface of the sensing grid. This can cause a nonlinear change in the equivalent dielectric constant, resulting in a noise floor voltage even under zero stress conditions.

[0078] An ultrasonic piezoelectric transducer configured in the edge encapsulation area emits a probe signal with a specific center frequency into the interior, and a receiver captures the residual feedback signal after propagation through the medium and boundary reflection.

[0079] Water molecule clusters will cause viscous absorption in the sound wave propagation path, resulting in high-frequency sound wave energy loss. In addition, the sound speed will vary slightly in the medium rich in water vapor, causing the arrival time of the wave peak to be delayed. The percentage drop of the feedback signal envelope amplitude relative to the detection signal can be calculated to determine the sound wave attenuation rate. By comparing the zero-crossing time difference of the transmitted and received waveforms, the phase delay that characterizes the transmission delay can be obtained.

[0080] Based on these two acoustic characteristic variables that are sensitive to ambient humidity, a compensation coefficient that can offset the drift of the current dielectric environment is determined. Before formally applying oblique shear stress to the grid nodes and scanning the voltage signal set over a large area, the compensation coefficient is used to perform a baseline zeroing calibration operation on all the original initial voltage readings captured by the analog-to-digital conversion channel. This results in a voltage signal set after baseline zeroing calibration that eliminates ambient moisture interference and reflects the potential changes caused by mechanical strain.

[0081] The voltage reading after baseline zeroing calibration can be determined, for example, in the following way: ,in, This indicates the voltage reading after baseline zeroing and calibration. This indicates the initial voltage reading. Indicates the compensation coefficient. This represents the baseline bias constant under standard conditions.

[0082] In one embodiment, determining the compensation coefficient based on the acoustic attenuation rate and phase delay includes: calling a pre-built dielectric constant drift mapping table; the dielectric constant drift mapping table contains dielectric constant drift values ​​corresponding to different combinations of acoustic attenuation rate and phase delay; inputting the acoustic attenuation rate and phase delay into the dielectric constant drift mapping table to perform an association search to determine the target drift value; determining the parasitic capacitance increment caused by environmental moisture adhesion based on the target drift value, and determining the corresponding compensation coefficient based on the parasitic capacitance increment.

[0083] By using an offline database with prior knowledge density to replace the complex and divergent real-time solution of differential equations, the test system can complete environmental calibration response in a shorter time. The dielectric constant drift mapping table can be pre-constructed through calibration experiments in a constant temperature and humidity chamber.

[0084] Since the electrical constant drift mapping table pre-stores the correspondence between the two inputs, different acoustic attenuation rates and phase delays, and the corresponding output, the dielectric constant drift value, the target drift value of the dielectric constant can be output more quickly.

[0085] The equivalent capacitance of the flexible cross-capacitance sensing grid embedded in the smart sports mat is positively correlated with the relative permittivity of the insulating medium. Based on the extracted target drift value and the inherent plate area and interlayer insulation thickness parameters of the grid, the parasitic capacitance increment caused by the adhesion and penetration of environmental moisture water molecules can be calculated and determined.

[0086] Based on the principle of charge conservation and the characteristics of AC impedance voltage divider networks, the increase in parasitic capacitance can be included in the global denominator for normalized division to solve for the corresponding compensation coefficient that can offset the effect of excess charge accumulation at the front end of the hardware amplifier.

[0087] The compensation coefficient can be determined, for example, in the following way: ,in, Indicates the compensation coefficient. This represents the reference capacitance parameter corresponding to the standard dielectric constant. This represents the increase in parasitic capacitance caused by the adhesion of environmental moisture.

[0088] Figure 3 This is a schematic diagram illustrating the structure of an intelligent sports mat electrical response testing system 1000 according to an exemplary embodiment. (Refer to...) Figure 3 The intelligent sports mat electrical response testing system 1000 includes a processor 1100 and a memory 1200. The memory 1200 stores computer program instructions, which, when executed by the processor 1100, implement all or part of the steps of the intelligent sports mat electrical response testing method in this application.

[0089] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only.

[0090] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for testing the electrical response of intelligent sports mats, characterized in that, include: During the test period, oblique shear stress was continuously applied to the sports mat, and X-ray images of the sports mat were obtained during the test period. The set of compression gradients covering the stress-affected area was then determined using the X-ray images. The compression gradient set contains multiple thickness change rates; The voltage signal set of the grid nodes of the sports mat during the test period is obtained. The extreme nodes are determined from the voltage signal set. The voltage drop characteristics between multiple target nodes distributed sequentially along the shear stress extension projection direction are obtained with the extreme nodes as the reference starting point. The attenuation gradient set covering the stress-affected area is determined based on the voltage drop characteristics. The attenuation gradient set contains multiple voltage drop rates; The contact origin is determined when oblique shear stress is applied to the sports mat. A reference coordinate system is constructed with the contact origin as a reference. The compression gradient set and the attenuation gradient set are projected and aligned into the reference coordinate system to obtain the spatial mapping matrix. Based on the thickness change rate and voltage drop rate associated with the spatial nodes of the spatial mapping matrix, the dynamic electromechanical coupling ratio of the spatial nodes is determined. Based on the dynamic electromechanical coupling ratio of multiple consecutive spatial nodes, the electrical response test results of the sports mat under shear stress are determined.

2. The method for testing the electrical response of intelligent sports mats according to claim 1, characterized in that, The set of compression gradients was determined using a set of X-ray fluoroscopic images, including: The target image representing the extreme shearing depth is determined from the X-ray fluoroscopic image set. The gray-level abrupt change rate between each adjacent pixel in the target image is determined. Based on the gray-level abrupt change rate, the density junction edge between the sensor array layer and the internal buffer layer in the target image is identified. The top and bottom contour lines are extracted based on the geometric contour trajectory of the density intersection edge, and the set of compressed gradients is determined based on the top and bottom contour lines.

3. The method for testing the electrical response of intelligent sports mats according to claim 2, characterized in that, The set of compression gradients is determined based on the top and bottom surface contours, including: The shear extension direction when oblique shear stress is applied is used as the horizontal reference axis, and multiple discrete acquisition points are determined on the horizontal reference axis. For each acquisition point, determine the orthogonal distance between the top and bottom contour lines that is perpendicular to the horizontal reference axis, and use the orthogonal distance as the corresponding spatial thickness. Based on the thickness difference between adjacent acquisition points, and combined with the spacing between adjacent acquisition points, the thickness change rate of each acquisition point is determined. The position coordinates of each acquisition point on the horizontal reference axis are extracted. Based on the arrangement order of the position coordinates, the thickness change rates of each acquisition point are sorted to obtain the compression gradient set.

4. The method for testing the electrical response of intelligent sports mats according to claim 1, characterized in that, Obtain the voltage drop characteristics among multiple target nodes sequentially distributed along the shear stress extension projection direction, and determine the attenuation gradient set covering the stress-affected region based on the voltage drop characteristics, including: Along the shear stress extension projection direction, the voltage values ​​of each target node distributed in adjacent spatial locations are read sequentially to determine the voltage difference between adjacent target nodes. The voltage drop rate of each target node is determined by combining the wiring spacing of the sensing grid with the voltage difference. Extract the position coordinates of each target node relative to the spatial reference starting point in the direction of shear stress extension projection, and arrange the voltage drop rates corresponding to each target node in sequence based on the arrangement order of the position coordinates to obtain the attenuation gradient set.

5. The method for testing the electrical response of intelligent sports mats according to claim 1, characterized in that, The spatial mapping matrix is ​​obtained by projecting and aligning the compressed gradient set and the decaying gradient set into the reference coordinate system, including: Using pre-calibrated scaling parameters, the coordinates of the acquisition points corresponding to the thickness change rate contained in the compression gradient set are projected proportionally onto the reference horizontal axis starting from the contact origin. The arrangement coordinates of the internal grid nodes are converted into geometric coordinates at a distance from the contact origin. In the reference coordinate system, the thickness change rate and voltage drop rate with the same geometric coordinates are bound together to obtain a spatial mapping matrix with a common data recording dimension.

6. The method for testing the electrical response of intelligent sports mats according to claim 1, characterized in that, Based on the thickness change rate and voltage drop rate associated with the spatial nodes in the spatial mapping matrix, the dynamic electromechanical coupling ratio of the spatial nodes is determined, including: Traverse the spatial nodes located in the spatial mapping matrix, extract the thickness change rate and voltage drop rate associated with the spatial nodes under the same data record dimension, and use the ratio of voltage drop rate to thickness change rate as the dynamic electromechanical coupling ratio corresponding to the spatial node.

7. The method for testing the electrical response of intelligent sports mats according to claim 1, characterized in that, Based on the dynamic electromechanical coupling ratio of multiple consecutive spatial nodes, the electrical response test results of the sports mat under shear stress are determined, including: Read the dynamic electromechanical coupling ratio of each space node and compare whether the dynamic electromechanical coupling ratio of each space node falls within the preset standard range; If the dynamic electromechanical coupling ratio falls within the preset standard range, the corresponding spatial node is determined as a normal node; or, if the dynamic electromechanical coupling ratio does not fall within the preset standard range, the corresponding spatial node is determined as an abnormal node. Based on the distribution of normal and abnormal nodes, the electrical response test results of the sports mat under shear stress are determined.

8. The method for testing the electrical response of intelligent sports mats according to claim 7, characterized in that, Based on the distribution of normal and abnormal nodes, the electrical response test results of the sports mat under shear stress are determined, including: The number of consecutive abnormal nodes along the shear extension direction and the deviation span corresponding to each abnormal node are counted. When the number of consecutive nodes exceeds a preset threshold, it is determined that the internal sensing medium of the sports mat is misaligned. The number of consecutive nodes and the deviation span are extracted to construct a defect test report for the misalignment state. Based on the defect test report, electrical test results characterizing the sports mat as unqualified are output.

9. The method for testing the electrical response of intelligent sports mats according to claim 1, characterized in that, Obtain the voltage signal set of the grid nodes during the applied oblique shear stress period, including: The feedback signal generated after transmitting a detection signal to the edge encapsulation area of ​​the sports mat is obtained, and the acoustic attenuation rate and phase delay between the feedback signal and the detection signal are determined. Based on the acoustic attenuation rate and phase delay, the compensation coefficient is determined. Before obtaining the voltage signal set of the grid nodes within the applied oblique shear stress period, the initial voltage readings are calibrated to baseline zero using the compensation coefficient to obtain the voltage signal set after baseline zero calibration.

10. An intelligent sports mat electrical response testing system, characterized in that, include: A processor and a memory, the memory storing computer program instructions that, when executed by the processor, implement the electrical response test method for intelligent sports mats according to any one of claims 1-9.

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