A constant pressure difference method-based air-permeable fabric intelligent detection and data management system

Abstract

The application relates to the technical field of fabric detection data management, and particularly discloses an intelligent detection and data management system for air-permeable fabric based on a constant pressure difference method, which comprises an airflow switching test module, a data acquisition module, a drift determination module and a result generation module. Under the condition of single fixing and clamping of a sample, the airflow switching test module controls the airflow to apply and maintain a target pressure difference in a forward-reverse alternating sequence, and performs preset odd-numbered cycle tests. The data acquisition module synchronously extracts a test area, records each forward and reverse steady-state flow to form a forward and reverse flow sequence, and forms a forward and reverse stable time sequence. The drift determination module calculates a flow drift rate based on the first and last values of the forward flow, and interrupts and outputs an instruction if the flow drift rate exceeds a limit. Otherwise, the directionality calculation module calculates a comprehensive directionality index. The result generation module compares the index with a limit threshold value, and outputs an air permeability characteristic detection report in combination with the area. The method realizes bidirectional alternation through single clamping, eliminates repeated clamping deviation, realizes real-time drift monitoring and damage prevention, accurately quantifies directionality, and provides an efficient and reliable scheme for air permeability evaluation.

Description

Technical Field

[0001] This invention belongs to the field of fabric testing data management technology, and relates to an intelligent testing and data management system for breathable fabrics based on the constant pressure difference method. Background Technology

[0002] With the development of textile technology, various functional fabrics such as brushed knit fabrics, embossed fabrics, and laminated composite fabrics are widely used. Their unique microscopic physical structure plays a crucial role in regulating the microclimate of the fabric. Meanwhile, breathability, as a fundamental indicator of a fabric's heat and moisture transfer efficiency, directly relates to the efficiency of gas exchange between the fabric's interior and exterior. Regardless of the substrate, the three-dimensional morphology of the internal pores is inextricably linked to the resistance to gas passage; maintaining stable breathability is irreplaceable for the fabric's fundamental functionality.

[0003] It is worth noting that, due to the different pile densities, groove depths, or multi-layered heterogeneous processes used in the manufacturing of some functional fabrics, the inherent asymmetry of their internal airflow channels makes the material extremely sensitive to the direction of airflow intrusion. When forward and reverse airflows pass through the same pore channels, they often face a significant difference in resistance. This makes the directional bias of breathability characteristics particularly significant in the selection of double-sided clothing for various scenarios or the construction of protective systems.

[0004] However, current assessments of the breathability of functional fabrics with asymmetrical structures have significant shortcomings. Firstly, traditional testing systems rely excessively on a single standard calculation path, often assuming equivalent breathability on both sides of the fabric while ignoring directional differences caused by internal heterogeneity. Even when attempting to compare the front and back sides step-by-step, the testing often requires interruption and reloading of the sample, subtly introducing external variables such as changes in boundary tension and abrupt deformation. More importantly, existing judgment criteria only record isolated static breathability values, failing to reflect the dynamic response of the fabric's microstructure after repeated switching of airflow directions, and lacking a systematic analysis of the variations and damage to the fabric's internal pore size due to alternating pressure. This results in current fabric characterization being largely a passive, unidirectional slice presentation, unable to systematically reveal the directional attenuation characteristics of fabric breathability in the early stages of material selection, causing a structural lag in overall fabric selection and performance depth assessment. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides an intelligent detection and data management system for breathable fabrics based on the constant pressure difference method to solve the above-mentioned technical problems.

[0006] To achieve the above and other objectives, the technical solution adopted by the present invention is as follows: This invention provides an intelligent detection and data management system for breathable fabrics based on the constant pressure difference method, comprising: The airflow switching test module is used to control the airflow switching mechanism to apply airflow in an alternating sequence of forward and reverse directions while maintaining a preset target pressure difference for a preset odd number of cyclic tests in a single fixed clamping state of the sample. The data acquisition module is used to extract the test area of ​​the sample during the cyclic test and record the forward steady-state flow rate after the forward airflow reaches the target pressure difference and stabilizes, forming a forward flow rate sequence; it also records the reverse steady-state flow rate after the reverse airflow reaches the target pressure difference and stabilizes, forming a reverse flow rate sequence; and it records the time elapsed from the application of the forward airflow until the flow rate fluctuation rate falls below the preset fluctuation threshold, forming a forward stable time series; and it also records the time elapsed from the application of the reverse airflow until the flow rate fluctuation rate falls below the preset fluctuation threshold, forming a reverse stable time series. The drift determination module is used to extract the first and last positive steady-state flows in the positive flow sequence, calculate the absolute value of the difference between the first and last positive steady-state flows, and determine the flow drift rate by the ratio of the absolute value of the difference to the first positive steady-state flow; and determine whether the flow drift rate is greater than the preset damage extreme value limit. The termination output module is used to interrupt the test and output a structural instability termination command when the flow drift rate exceeds the preset damage extreme limit. The directionality calculation module is used to calculate the comprehensive directionality index based on the forward flow sequence, reverse flow sequence, forward stable time series and reverse stable time series when the flow drift rate is not greater than the preset damage extreme limit. The results generation module is used to compare the comprehensive directional index with the preset directional limit threshold, and generate and output an air permeability test report based on the comparison results and the test area.

[0007] As described above, the intelligent detection and data management system for breathable fabrics based on the constant pressure difference method provided by the present invention has at least the following beneficial effects: This invention utilizes a coordinated control system between the airflow switching test module, data acquisition module, and drift determination module. Under a single fixed clamping condition of the sample, it automatically executes a preset odd number of alternating forward and reverse airflow cycles, recording in real time the forward and reverse steady-state flow rates after each target pressure difference is reached and stabilized, along with the stabilization time required for each. Based on this, the drift determination module extracts the first and last values ​​of the forward flow rate sequence, calculates the flow drift rate, and compares it with a preset damage extreme limit, thereby outputting a structural instability termination command or triggering subsequent directional calculations. This design uses the flow drift rate as a dynamic structural stability indicator, enabling real-time judgment of whether irreversible damage or performance drift occurs during cyclic loading. This effectively avoids invalid tests or misjudgments caused by neglecting structural state changes in traditional methods. When the drift rate exceeds the damage extreme limit, the test is actively interrupted, saving test time and preventing sample damage or subsequent data distortion. This adaptive termination mechanism significantly improves the reliability and safety of permeability testing.

[0008] Furthermore, when the flow drift rate is within a controllable range, the present invention uses a directionality calculation module to comprehensively calculate a comprehensive directionality index that characterizes the material's permeability direction dependence based on the forward flow sequence, reverse flow sequence, forward stable time sequence, and reverse stable time sequence. This index is then compared with a preset directionality threshold, and a detailed permeability characteristic test report is generated by combining the test area. In this process, the comprehensive directionality index simultaneously integrates the differences in steady-state flow rate and the differences in the rate of stabilization, thereby more comprehensively and sensitively characterizing the differences in the permeability behavior of the sample under different airflow directions, avoiding the one-sidedness caused by a single index. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram showing the connections of the various modules in the system of the present invention.

[0011] Figure 2 This is a schematic diagram showing the logical steps of the present invention.

[0012] Figure 3 This is a schematic diagram illustrating the positive flow fluctuation rate and stability determination process provided by the present invention. Detailed Implementation

[0013] The present invention will be further described in detail below with reference to specific embodiments. The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the inventive concept or exceed the scope defined by the claims, all of which should fall within the protection scope of the present invention.

[0014] Example 1: Please see Figure 1-3 As shown, a smart detection and data management system for breathable fabrics based on the constant pressure difference method includes an airflow switching test module, a data acquisition module, a drift determination module, a termination output module, a directionality calculation module, and a result generation module. The various modules are connected via wired and / or wireless connections to enable data transmission between them; The airflow switching test module is used to control the airflow switching mechanism to apply airflow in alternating forward and reverse order when the sample is in a single fixed clamping state. The airflow switching mechanism uses an internally integrated multi-directional electromagnetic reversing valve group to achieve physical reversal of the air pressure application direction without releasing the fabric clamp, and maintains the preset target pressure difference for a preset odd number of cycle tests.

[0015] In this embodiment of the invention, after the sample is clamped, the system reads the preset target pressure difference and the preset total number of test cycles. The target pressure difference is usually set according to the standard thickness of the fabric being tested and the national testing standard. Since 10-130 mmHg is used, the setting range is 1333 Pa to 17332 Pa. The preset logic requirement for the total number of test cycles is that it must be an odd number not less than 3, and it is recommended to set it to 5 or 7 times. The physical meaning of this setting is to force the airflow impact direction of the first starting stage and the last ending stage of the entire test process to be consistent. For example, both are set to blow air from the front to the back, so that after a closed-loop test without unloading the fabric, the steady-state flow data of the sample before and after being impacted by multiple alternating airflows in the same direction can be directly extracted.

[0016] Upon entering the pressurization phase, the system activates the airflow switching mechanism and begins the first round of positive airflow application. Considering that breathable fabrics with fleece or laminated structures undergo directional deformation similar to an outward bulge of a tympanic membrane upon impact with airflow, causing dynamic changes in the equivalent volume of the test chamber, directly driving the airflow with constant power would make it difficult to maintain the stable constant pressure required for the test. Therefore, the system's main control chip employs an adaptive damping adjustment algorithm to update the fan's drive voltage in real time, gradually approaching and locking the chamber pressure to the target pressure difference. Specifically, within each fixed control sampling cycle, the main control chip acquires the real-time pressure difference value returned by the chamber's micro-pressure sensor. The control sampling cycle is determined based on a combination of the mechanical closing delay of the reversing solenoid valve and the inertial response time of the fan rotor, typically set to half of the upper limit of the hardware mechanical delay. The drive voltage control quantity for the current cycle is then calculated using the following formula: ; This represents the drive voltage output to the fan speed control terminal at the current sampling moment, in volts. This indicates the driving voltage that was output at the previous sampling time. The target pressure difference is a preset value, expressed in Pascals. and These represent the real-time pressure difference inside the cavity actually collected at the current moment and the previous moment, respectively, in Pa; This represents the fixed sampling time interval set by the chip's hardware timer, in seconds.

[0017] This is the differential pressure tracking coefficient, defined in V / Pa, and physically represents the voltage compensation increment required per unit of differential pressure deviation. The preset logic for this value is based on the work margin of the hardware electromechanical conversion. The specific preset steps are as follows: During the no-load calibration test phase at the system's factory, the system outputs the highest safe drive voltage to the drive end of the airflow switching mechanism. Simultaneously, it reads the ultimate static pressure difference that the sensor can achieve under completely sealed and unloaded conditions in the test chamber. Based on this, the system executes the calculation formula. , where k is the built-in overload margin constant, thus eliminating the need for manual parameter tuning and directly binding the coefficients to the maximum output capacity of the hardware; k is the overload margin coefficient. To enable the control gain to adapt to different batches of hardware without relying on manual experience, the system establishes preset logic and calculates this coefficient based on the factory specifications of the pneumatic actuator motor: extracting the maximum continuous safe operating rated current fixed in the communication protocol of the underlying fan motor nameplate. And extract the highest safe drive voltage at the output. The ultimate peak total current actually measured by the system current probe The processor executes the calculation formula. .

[0018] This is the differential pressure damping coefficient, defined in V·s / Pa, used to suppress sudden changes in intracavitary pressure as it approaches the target value. Its preset logic is based on the physical volumetric inertia and time constant of the pneumatic chamber. The specific preset steps and calculation formulas are as follows: During the calibration phase, a step test voltage is applied to the air pump. The recorded intracavitary pressure rose from the ambient reference pressure to 63.2% of the steady-state pressure, which is the natural index characteristic. The inherent airflow lag time consumed And the final steady-state pressure difference. The system then performs calculations based on the physical transfer function relationship. .pass This gives the damping coefficient the ability to precisely match the dynamic response characteristics of the current chamber volume, ensuring a smooth and overshoot-free pressure regulation process.

[0019] The system drives the fan speed until the real-time pressure difference stabilizes at the target pressure difference, and during this stage, it collects steady-state flow data of the sample. Once the data acquisition for a single forward test is completed and the specified duration has been reached, the system switches to airflow reversal operation. To maintain the current clamping state of the sample from vibration interference caused by the reversal, the system does not release the clamping force of the fixture, but instead sends a level reversal signal to the four-way solenoid reversing valve assembly in the air circuit.

[0020] During the brief transition period of the valve core's mechanical switching, due to the strong airflow collision and turbulence within the cavity, the actual pressure difference exhibits irregular pulsations. The micro-pressure sensor is in a data-shielded state and does not read data. Instead of powering off and shutting down, the main control chip rapidly reduces and locks the fan drive voltage to 10% of its current value, maintaining a small baseline airflow within the pipeline to prevent static friction delays during restart caused by a complete stop of the fan rotor. Once the reversing valve's stroke is complete, the micro-pressure sensor's acquisition polarity is reversed and mapped synchronously within the internal logic. Using this 10% baseline voltage as the starting point, the system again invokes the aforementioned adaptive damping adjustment algorithm, driving the measured pressure difference back to the target pressure difference via reverse airflow and acquiring the reverse flow rate. Regardless of whether it is a forward or reverse sequence, the sampling starting point for the steady-state flow rate is set at the moment after the pressure difference reaches the target pressure difference, while the timing starting point for the stabilization duration is uniformly set at the start time of the applied airflow. Even if the difference between the first round of pressure building from zero and the subsequent rounds of pressure building from 10% low pressure is objectively reflected in the final measured stabilization duration, the impact of 10% low pressure can be ignored and will not affect the final extracted steady-state flow characteristic data.

[0021] The system will continuously accumulate the number of alternating executions of forward pressurization and reverse pressurization according to the set counting rules. When the accumulated value reaches the initially set odd number of times limit, the system will actively output a shutdown signal to shut down the fan and reset the gas circuit valves. Finally, the system will collect the pressure difference, time and flow data collected in each iteration.

[0022] The data acquisition module is used to extract the test area of ​​the sample during the cyclic test and record the forward steady-state flow rate after the forward airflow reaches the target pressure difference and stabilizes, forming a forward flow rate sequence; record the reverse steady-state flow rate after the reverse airflow reaches the target pressure difference and stabilizes, forming a reverse flow rate sequence; and record the time elapsed from the application of the forward airflow until the flow rate fluctuation rate falls below the preset fluctuation threshold, forming a forward stable time series; and record the time elapsed from the application of the reverse airflow until the flow rate fluctuation rate falls below the preset fluctuation threshold, forming a reverse stable time series.

[0023] Preferably, the duration from the application of the forward airflow until the flow rate fluctuation rate falls below a preset fluctuation threshold is recorded to form a forward stable time series; the forward steady-state flow rate after the forward airflow reaches the target pressure difference and stabilizes is recorded to form a forward flow rate series, including: After each time the airflow switching mechanism applies positive airflow and the pressure difference reaches the target pressure difference, the instantaneous flow rate value is continuously extracted according to the preset sampling period; A sliding time window is constructed with the current sampling time as the endpoint. The relative standard deviation of all instantaneous flow values ​​within the sliding time window is calculated as the flow fluctuation rate at the current moment. In other words, the hardware layer continuously samples at a fixed frequency from the moment the intracavity pressure difference reaches the target pressure difference. The software layer allocates a fixed-length data queue with a first-in-first-out mechanism in memory. This queue only retains data within the time span covered by the current sliding window length. Old data is directly discarded to ensure the timeliness of the flow fluctuation rate calculation. A sliding time window is constructed with the latest sampling time as the endpoint and traces back a fixed number of historical sampling points. For example, the recommended sampling period is 20 milliseconds, and the sliding window length is preset to 50 sampling points. Then, this window always frames the dynamic data within the past 1 second, and then calculates the flow fluctuation rate at the current moment. When the flow fluctuation rate is lower than the preset fluctuation threshold for multiple consecutive sampling periods, the current sampling time is determined as the stable arrival point; where multiple sampling periods refer to 3 to 5 consecutive periods, preferably 3 consecutive periods; Extract the time span from the start of applying the positive airflow to the determination of the stable arrival point as the positive stability duration of the current round, and add the positive stability duration to the positive stability time series; Extract the arithmetic mean of all instantaneous flow values ​​within the sliding time window as the positive steady-state flow for the current cycle, and add the positive steady-state flow to the positive flow sequence.

[0024] In this embodiment of the invention, when the system initializes and enters the acquisition state, the main control chip reads the calibration parameters of the currently assembled test fixture and directly extracts the test area of ​​the sample, with the area value in square centimeters. As the airflow switching mechanism operates and begins to apply positive airflow, the hardware timer inside the system starts counting from zero. When the real-time pressure difference fed back by the intracavity micro-pressure sensor first climbs and reaches the target pressure difference, the digital flow sensor begins to continuously extract the instantaneous flow rate value flowing through the sample according to the preset sampling period. Here, it is recommended to set the preset sampling period in an adjustable range between 10 milliseconds and 50 milliseconds. In order to capture the waveform details of small airflow oscillations and avoid excessive occupation of the processor bus bandwidth by high-frequency interrupts, it is recommended to preferably set it to sample once every 20 milliseconds.

[0025] To determine whether the fabric flow resistance under dynamic stress has stabilized, the system constructs a sliding time window in memory, with the current sampling moment as the endpoint. The length of this sliding time window is preset to contain a fixed number of sampling points. For example, assuming a preset sampling period of 20 milliseconds, selecting a length of 50 sampling points corresponds to a one-second time span. Each time a new instantaneous flow value is acquired and pushed to the bottom of the window queue, the oldest sampled value is simultaneously removed. The system then extracts all existing instantaneous flow values ​​within the sliding time window, calculates their relative standard deviation, and directly uses this deviation value as the flow fluctuation rate at the current moment. The specific formula for calculating this flow fluctuation rate is as follows: ; In this calculation formula, RSD(t) represents the flow fluctuation rate calculated at the current sampling time, expressed as a percentage value; This represents the total number of sampling points included in the sliding time window, and its value is a preset positive integer. The instantaneous flow rate value corresponding to the j-th sampling point within the sliding window, in liters per minute; All within the current sliding window The formula is the arithmetic mean of instantaneous flow rates, all in liters per minute. This formula is a specific application of the classical statistical coefficient of variation formula. The advantage of using it directly as a volatility assessment model here is that fabrics of different thicknesses and densities have vastly different absolute air permeability. If only absolute variance is used for assessment, it is easy for thin fabrics with high flow rates to never meet the standard, while thick fabrics with low flow rates to prematurely meet the standard. Using division by the moving average... The method can adaptively normalize the basic flow rate, so that a uniform stability criterion can be used for samples of different materials.

[0026] After calculating the current flow fluctuation rate, the system compares it in real time with an internally preset fluctuation threshold. This preset fluctuation threshold is typically set between 1% and 3%, with a recommended and preferred setting of 2%. Considering that transient vortex interference may occur in the airflow within the pipeline, even if the fluctuation rate calculated in a single instance falls below the threshold, it does not necessarily mean that the fabric deformation and airflow channel have completely established a steady state. Therefore, the system introduces a continuous verification mechanism, requiring that as the sliding window continuously advances with sampling, an updated flow fluctuation rate value is output for each sampling step. When the window continues to slide and multiple consecutively output flow fluctuation rate values ​​are all below the preset fluctuation threshold, the system determines the stable arrival point. The specific number of consecutive determinations is set as an empirical verification span, i.e., 3 to 5 consecutive cycles as mentioned above, preferably 3 consecutive cycles in this embodiment. Once this condition is met, the system immediately locks the current data acquisition time and establishes it as the stable arrival point. Subsequently, the system reads the value from the hardware timer, extracts the accumulated time span from the initial application of the forward airflow to the determined stable arrival point, and uses this as the forward stable duration for the current cycle, in seconds, storing it in a designated memory address to form a forward stable time series. Simultaneously, to avoid potential sensor noise errors that might be introduced by extracting single-point data, the system does not use the individual flow rate value at the last moment. Instead, it extracts the arithmetic mean of all instantaneous flow rate values ​​remaining within the sliding time window at that moment as the forward steady-state flow rate for the current cycle, in L / min, and archives it into the forward flow rate series.

[0027] After the first round of forward testing is completed and the system-driven valve switches to reverse airflow application, the main control program clears the previous sliding time window cache and resets the timer to zero. Similar to the acquisition logic of the forward test, when the reverse airflow pressure difference reaches the target pressure difference, the flow sensor extracts the instantaneous flow rate value of the reverse flow through the fabric at a preset sampling period of 20 milliseconds and pushes it into a new time window. The system calls the exact same relative standard deviation calculation formula to process the reverse flow data within the window, continuously calculating the flow fluctuation rate under the impact of the reverse airflow. After monitoring that multiple consecutively output reverse flow fluctuation rate values ​​are all below the preset fluctuation threshold, a stable point is confirmed. The number of these multiple reverse flow fluctuation rate values ​​is also set to 3 to 5 consecutive values, preferably 3 consecutive values. The system then extracts the time span from the start of the reverse airflow application to the determined stable point as the reverse stabilization duration and includes it in the reverse stabilization time series. Similarly, the global average of the instantaneous reverse flow rate within the frozen window at this time is extracted as the reverse steady-state flow rate and combined and written into the reverse flow series. During the odd number of pressurization cycles, the system repeatedly reuses this window stability mapping logic, and finally outputs the regularized time and flow rate characteristic parameters to the downstream drift determination module.

[0028] The drift determination module is used to extract the first and last positive steady-state flows in the positive flow sequence, calculate the absolute value of the difference between the first and last positive steady-state flows, and determine the flow drift rate by the ratio of the absolute value of the difference to the first positive steady-state flow; and determine whether the flow drift rate is greater than the preset damage extreme value limit.

[0029] In this embodiment of the invention, after the airflow switching test phase is completed, the main processing chip first intervenes to check the validity of the collected basic data. The processing unit retrieves the positive flow sequence stored in the memory area through the internal bus, and according to the memory address offset, first reads the first positive steady-state flow from the beginning of the sequence. This data is measured when the sample is just clamped and the first positive air pressure is applied, and it characterizes the basic air permeability benchmark of the fabric in its initial state before being subjected to multiple alternating air pressure stress impacts. Next, the processing unit counts the length of the sequence and extracts the last positive steady-state flow from the last position of the sequence. Since the control logic of the preceding test phase requires that the total number of cycles must be odd, this physically ensures that the direction of the first air pressure loading and the last air pressure loading are absolutely consistent. This setting allows the first and last steady-state flows to be directly compared on the same force direction plane, avoiding the comparison error introduced by the resistance difference between the front and back sides of the fabric.

[0030] To quantify the degree of irreversible change in the permeability of the sample after multiple forward and reverse stretching events, the processing unit introduced a flow drift rate calculation step. The underlying algorithm module subtracts the first and last extracted forward steady-state flow rates, takes the absolute value of the result, and then uses this absolute value as the numerator, with the initially read first forward steady-state flow rate as the base denominator to calculate the ratio. The specific calculation logic is expressed as follows: ; The calculated flow drift rate is expressed as a decimal without physical units. This represents the first positive steady-state flow rate extracted above, expressed in liters per minute; This represents the last positive steady-state flow rate extracted above, also expressed in liters per minute. Absolute values ​​are used in this calculation because the structural damage to the fabric under alternating wind pressure manifests in two opposing dimensions. One scenario is that fabric yarns slip or the membrane pores are torn and enlarged by wind pressure, leading to a decrease in flow resistance in the later stages of the test, resulting in the last positive steady-state flow rate being greater than the first value. The other scenario is that long fibers on the fabric surface or the filling material within the interlayers permanently collapse and clump due to alternating wind pressure kneading, thus blocking the original breathable micropores, causing the last positive steady-state flow rate in the later stages of the test to be less than the first value. Using absolute values ​​ensures that both pore enlargement and pore blockage are ultimately mapped to a uniform positive deviation, facilitating consistent evaluation.

[0031] After obtaining the flow drift rate, the processing unit compares it with the preset damage limit stored in the system's underlying configuration file. The preset logic for this damage limit is typically based on the empirical tolerance value for the elastic recovery rate of fabrics in national textile standards. Studies show that when fabric yarns experience 5% irreversible structural yielding tension, the change in porosity leads to an approximately proportional decrease in air permeability. For common outdoor functional composite fabrics, this limit is generally fixed at 0.05. If the processor's calculations determine that the current flow drift rate exceeds the preset damage limit, it indicates that, physically, after several rounds of alternating positive and negative wind pressure, the fabric's fiber structure has undergone plastic damage exceeding its elastic deformation range or irreversible fatigue damage. In the event of such damage, all subsequent flow and time data actually reflect the state of a damaged fabric and cannot represent the true inherent directional air permeability properties of the sample. Therefore, once the data flow rate exceeds this limit, the processing program will directly intercept the data flow at this step, terminate the calculation of subsequent directional parameters, and output a message to the external screen indicating that the test sample has been damaged by the airflow and is structurally invalid. Conversely, if the flow drift rate is less than or equal to the preset extreme limit, it indicates that the sample has maintained good structural elasticity and recovery ability during the test, and the system will then allow the data of the current batch to proceed to the next stage for in-depth air permeability directional characteristic analysis.

[0032] The termination output module is used to interrupt the test and output a structural instability termination command when the flow drift rate exceeds the preset damage extreme value limit.

[0033] Preferably, if the flow drift rate exceeds a preset damage extreme limit, the test is interrupted and a structural instability termination command is output, including: When the flow drift rate is determined to be greater than the preset damage extreme limit, the forward airflow is cut off and the subsequent cycle test is terminated. Extract the absolute value of the first and last ranges of two adjacent tests based on the sorting of the positive flow sequence; If the absolute value of the first and last ranges is not greater than the preset mutation threshold, the sample is determined to have undergone progressive fatigue damage. If the absolute value of the first and last ranges is greater than the preset mutation threshold, the sample is determined to have suffered transient fracture damage. The progressive fatigue damage results and transient fracture damage are converted into diagnostic logs, which are then encapsulated into structural instability termination instructions and output.

[0034] In this embodiment of the invention, once it is determined that the flow drift rate exceeds the preset damage limit, the main processing chip will immediately respond and send a hardware-level emergency stop control signal to the airflow switching mechanism. This signal will forcibly disconnect the power module of the operating fan and simultaneously release the exhaust bypass valves around the test chamber for pressure relief, thereby physically cutting off the application of forward airflow and completely terminating any subsequent unfinished cyclic pressurization tests. This timely hardware interruption mechanism is to prevent the fan from running under overload for an extended period due to pressure loss after the fabric is torn, and also to lock in the on-site status for the next step of failure cause data analysis.

[0035] Although excessive deformation of the fabric during testing constitutes a test failure, the data from this structural damage process still has analytical value reflecting the material's tensile strength. Therefore, the processing unit retrieves the forward flow sequence previously stored in memory. Since the forward flow sequence is stored sequentially with each forward pressurization process, the data in the sequence sequentially represents the unidirectional fabric flow resistance state of the first, second, and final rounds before the interruption. The processor iterates through this sequence using software loop instructions and performs table lookups and subtraction operations on adjacent data. Specifically, it extracts the forward steady-state flow rate of the subsequent test and subtracts it from the forward steady-state flow rate of the previous test, then calculates the absolute value of this difference, which serves as the absolute value of the first and last range between the two. This extracted absolute range effectively quantifies the dimension of a single displacement of the pore size of the sample after experiencing one round of alternating forward and reverse wind and pull, with the unit consistent with the base flow rate, liters per minute.

[0036] After obtaining the absolute values ​​of the first and last ranges of all adjacent test rounds, the system compares them one by one with a preset mutation threshold set in memory. Regarding the preset mutation threshold's logic, considering that the base air permeability of fabrics with different substrate thicknesses can differ by tens or hundreds of times, using a fixed, rigid flow rate absolute value as the boundary would result in thin fabrics never exceeding the limit while thick fabrics are extremely prone to exceeding it. Therefore, the system adopts a dynamic floating binding setting logic. That is, when the first positive steady-state flow rate is initially read, a fixed threshold specific to the current situation is pre-calculated according to a ratio of 3% to 5% of its value as the preset mutation threshold, and its unit is also normalized to liters per minute. The main control chip continuously compares each set of absolute range values ​​generated in the sequence. If it determines that all absolute range values ​​are not greater than the preset mutation threshold, it indicates that the fabric did not suddenly break, but rather that the internal yarns under continuous alternating stress underwent stress yielding and cumulative slip deformation as the number of tests increased. Based on this, the system qualitatively determines the physical state of the sample as progressive fatigue damage.

[0037] Conversely, if even one value in the calculated absolute range of this set exceeds the preset mutation threshold, it indicates that during a reversal of the positive and negative wind pressure action, the internal base fabric or surface waterproof coating of the sample could not withstand the instantaneous internal and external pressure difference, resulting in instantaneous base tearing or coating collapse, causing a large amount of airflow to suddenly penetrate through the breach. In this case, the processing system will directly qualitatively determine the failure characteristics of the sample as transient rupture damage. After obtaining the final diagnostic qualitative result, the encoding unit inside the chip will convert the specific cycle number of the abnormality, the specific steady-state flow rate corresponding to the current force direction obtained from the last test that triggered the mutation, and the aforementioned progressive fatigue damage conclusion or transient rupture damage conclusion into hexadecimal, and organize them into a standard readable text character array to form a diagnostic log. Finally, the communication module uses this diagnostic log as the core data load, fully encapsulates it into the data frame protocol body of the structural instability termination instruction, and broadcasts it to the external host computer software or local touch screen through the device bus, prompting the tester to replace the sample and record the specific fatigue resistance limit performance of the fabric.

[0038] The directionality calculation module is used to calculate the comprehensive directionality index based on the forward flow sequence, reverse flow sequence, forward stable time series, and reverse stable time series when the flow drift rate is not greater than the preset damage extreme limit.

[0039] Preferably, the comprehensive directionality index is calculated based on the forward flow sequence, the reverse flow sequence, the forward stable time series, and the reverse stable time series, including: The static flow asymmetry is calculated from the forward and reverse flow sequences. The dynamic response lag ratio is calculated from the forward stable time series and the backward stable time series. Obtain the system's preset primary and secondary weight parameters; The flow distribution assessment value is obtained by multiplying the sovereign re-parameter with the static flow asymmetry. The deformation time evaluation value is obtained by multiplying the secondary weight parameter with the dynamic response lag ratio. The flow distribution assessment value and the deformation time assessment value are added together, and the result is used as the comprehensive directionality index.

[0040] Preferably, the static flow asymmetry is calculated from the forward and reverse flow sequences, including: The average forward flow rate is obtained by calculating the average of all values ​​in the forward flow sequence, and the average reverse flow rate is obtained by calculating the average of all values ​​in the reverse flow sequence. Calculate the absolute value of the difference between the forward average flow rate and the reverse average flow rate; Compare the magnitudes of the forward average flow and the reverse average flow, and extract the largest value of the two as the extreme value benchmark flow. Divide the absolute value of the difference by the extreme baseline flow rate, and use the calculated quotient as the static flow asymmetry.

[0041] Preferably, the dynamic response lag ratio is calculated by examining the forward-stable time series and the reverse-stable time series, including: The forward average settling time is obtained by calculating the average of all values ​​in the forward stable time series, and the reverse average settling time is obtained by calculating the average of all values ​​in the reverse stable time series. Calculate the absolute value of the difference between the forward average settling time and the reverse average settling time; Compare the magnitudes of the forward average settling time and the reverse average settling time, and extract the one with the largest value as the extreme response time. Divide the absolute value of the difference by the extreme response time, and use the calculated ratio as the dynamic response lag ratio.

[0042] Preferably, the system-preset primary weight parameters and secondary weight parameters are obtained, including: Extract the global minimum stable time from the forward stable time series and the backward stable time series; The global minimum settling time is compared with the preset rigid reference time, and the excess value between the two is obtained. The excess difference is divided by the set adjustment step size coefficient to generate the dynamic offset. The set adjustment step size coefficient is an empirical constant with time dimension. Its function is to perform a uniform division operation on the excess difference with time unit, so that the time dimension is canceled out between the numerator and denominator, ensuring that the calculated dynamic offset is a dimensionless value.

[0043] Add the dynamic offset to the preset basic dynamic weight parameters to obtain the secondary weight parameters; The main weight parameter is calculated by subtracting the secondary weight parameter from the number 1.

[0044] In this embodiment of the invention, if it is determined that the flow drift rate has not exceeded the preset damage extreme limit, the main processing chip takes over the various data sequences previously temporarily stored in memory and initiates directional quantitative analysis of the sample's air permeability characteristics. The primary processing step focuses on the cross-directional comparison of the fluid's steady-state flow capacity. The processor traverses and reads the forward flow sequence constructed by the previous acquisition process, calculates the forward average flow by accumulating the single measurement values ​​within all recording cycles and dividing by the total number of records, with its physical dimension being liters per minute. The processor performs the same calculation steps on the reverse flow sequence to obtain the reverse average flow. Considering the physical differences between the front and back sides of the fabric in terms of macroscopic textile structure, such as the thickness of the surface pile or back coating, the algorithm module uses a subtraction instruction to obtain the absolute value of the difference between the forward average flow and the reverse average flow. Considering that the base air permeability may vary by tens of times between different materials, such as heavy canvas and light mesh fabric, the system does not directly use the difference itself, but extracts the larger of the above forward and reverse average flow values ​​through an internal comparator and sets it as the extreme value reference flow. Then, the absolute value of the difference is used as the dividend, and the extreme baseline flow rate is used as the divisor to perform a division operation. The derivation of this operation process is as follows: ; in This represents the calculated static flow asymmetry. and The forward and reverse average flow rates are represented respectively, both in liters per minute.

[0045] For fabrics containing elastic substrates or suspended composite layers undergoing directional pressurization, the processor retrieves both forward and reverse steady-state time series for dynamic response evaluation. Similar to flow averaging, the processing unit calculates the arithmetic mean of the forward and reverse time series spans to obtain the forward and reverse average steady-state times, both in seconds, representing the compressive densification process. The processor then calculates the absolute difference between these two time indices and extracts the larger value as the extreme response time measuring the longest deformation span of the structure. Dividing the absolute difference by the extreme response time yields the dynamic response hysteresis ratio. This formula is derived from the static flow resistance discrimination formula. ; The dynamic response hysteresis ratio represents the characteristic of the bidirectional bulging delay difference. and The average deformation time in each direction is measured in seconds. The time dimension is eliminated by the divisor distribution law. If the deformation times in the forward and reverse directions are the same, the ratio converges to zero. The greater the relative difference in the deformation time in the forward and reverse directions, the more significantly the value increases and approaches the number 1, which intuitively reflects the inconsistency in the peeling or stretching of the interlayer tension between the two layers of the composite fabric.

[0046] After establishing static indicators based on flow factors and dynamic indicators based on time factors through preliminary calculations, the processing architecture needs to couple and calibrate the weights of these two factors. Unlike traditional methods that use fixed weights, the chip introduces a weight self-feedback adjustment mechanism that adapts to the physical properties of the bonding material. After all cyclic test rounds are successfully completed, the computational kernel scans all historical stable time data points in both forward and reverse directions using an extreme value search algorithm. It extracts the set of data with the shortest execution time in each cycle in both directions as the global minimum stable time. This data reflects the basic response agility of the sample body in its optimal state. The system compares this global minimum stable time with the underlying preset rigid reference time. The preset logic of the rigid reference time is based on the inherent pressure build-up delay of the pipeline and valves under the same target pressure difference, obtained from testing with a thick, non-permeable, inelastic metal disc assembled at the system's factory. This delay typically fluctuates between 0.1 and 0.3 seconds. The difference obtained by comparing and subtracting the two represents the delay increment caused by the elastic deformation of the sample itself. To eliminate dimensional constraints, the processor divides the time-dimensioned difference by the adjustment step size coefficient in the system configuration file. The step size coefficient is set to seconds, derived from the fundamental physical property parameters fixed at the system's core. This parameter is based on the statistical median of the maximum bulging time of a large number of different types of breathable fabric substrates measured during factory calibration. Because it uses a universal statistical median, the system can adaptively accommodate various fabrics during operation, eliminating the need for manual mapping for specific fabric types. The median is used to filter out extreme outliers from extremely thick or thin test samples. This division operation maps to the dynamic offset, which is then obtained. The dimensionless fundamental dynamic weight parameter is read from the basic data memory. In conventional stiff woven fabrics, this default constant value is generally between 0.15 and 0.25. This value is added to the dynamic offset to directly form the secondary weight parameter specific to the current deformation level. Based on this, using 1 as the base of the total probability distribution, the calculated secondary weight parameter is subtracted to deduce the primary weight parameter used to constrain static elements.

[0047] Finally, the processor issues a parallel digital multiplication instruction, multiplying the sovereign weight parameter by the previously locked static flow asymmetry, and the resulting product is defined as the flow distribution evaluation value; multiplying the secondary weight parameter by the similarly calculated dynamic response hysteresis ratio, the resulting product is defined as the deformation time evaluation value. The processor then combines the two by arithmetic addition: ; In the formula This represents a comprehensive directional index; and These are the primary and secondary weights derived from adaptive calculation.

[0048] The results generation module is used to compare the comprehensive directional index with the preset directional limit threshold, and generate and output an air permeability test report based on the comparison results and the test area.

[0049] Preferably, the comprehensive directional index is compared with a preset directional threshold, and a breathability test report is generated and output based on the comparison result and the test area, including: When the comprehensive directionality index is less than the preset directionality limit threshold, all values ​​of the forward flow sequence are extracted and the average value is taken as the first flow mean, and all values ​​of the reverse flow sequence are extracted and the average value is taken as the second flow mean. Calculate the sum of the first average flow rate and the second average flow rate, and divide the sum by two to obtain the global baseline flow rate; The characteristic air permeability is calculated by dividing the global baseline flow rate by the test area and multiplying it by the internally preset unit conversion factor. The sample was identified as a fabric label without significant directional properties, and the characteristic air permeability was combined with the fabric label without significant directional properties to generate and output an air permeability test report.

[0050] Preferably, the generation of the breathability test report also includes: When the comprehensive directionality index is not less than the preset directionality limit threshold, extract all values ​​of the forward flow sequence, calculate the average value, divide it by the test area and multiply it by the preset unit dimension conversion factor to obtain the forward air permeability value; extract all values ​​of the reverse flow sequence, calculate the average value, divide it by the test area and multiply it by the unit dimension conversion factor to obtain the reverse air permeability value. Compare the forward breathability value with the reverse breathability value, extract the one with the larger value, and mark the corresponding fabric side attribute as the breathable side identifier. The sample is identified as a fabric with a significant directional label. The significant directional fabric label, the forward air permeability value, the reverse air permeability value, the easily breathable side label, and the comprehensive directional index are packaged together to generate and output an air permeability test report.

[0051] In this embodiment of the invention, the previously obtained comprehensive directional index is read and compared with a preset directional threshold value stored in the memory. The logic for setting this preset directional threshold value is mainly based on past sampling statistics of the bidirectional air permeability performance of a large number of single-layer symmetrical basic fabrics under the same wind pressure environment. For basic fabrics without physical coatings or obvious differences in front and back weaves, the flow resistance deviation caused by pressure is usually simply manifested as environmental noise and mechanical test tolerance. Statistically, the extreme value of this natural error is usually distributed between 8% and 12%. To avoid misjudging normal test fluctuations as functional structural guidance, the preset directional threshold value is set as a constant of 0.1.

[0052] When the processor core comparison finds that the overall directionality index is less than the evaluation threshold, the program flow determines that the current test object physically exhibits a bidirectional symmetrical airflow state. Under this determination branch, the processing unit first extracts all floating-point values ​​constituting the forward flow sequence from the read-only memory area, performs discrete summation, and then divides by the total number of cycles to calculate the first average flow rate representing the forward equivalent flow resistance. Similarly, the processing unit extracts the reverse flow sequence and performs the same averaging operation to obtain the second average flow rate. Since the fabric has been determined to be non-directional, distinguishing between the front and back surfaces is no longer meaningful for practical process applications. The processing unit arithmetically adds the first average flow rate and the second average flow rate, divides by two, and takes the average to calculate the global reference flow rate that smooths out minimal disturbance deviations. Subsequently, the processing unit retrieves the sample test area recorded during equipment initialization and performs a physical dimension conversion of the air permeability. The core formula for this conversion is: ; The characteristic air permeability is physically defined as the length of the air column that passes vertically through a unit area of ​​the sample per unit time under a preset pressure difference, and the unit is millimeters per second. The global baseline flow rate is measured in liters per minute, maintaining the dimensions of the direct output from the hardware digital flow sensor. The air opening area of ​​the test fixture obtained during the initialization phase is expressed in square centimeters. This is to eliminate the discontinuity in the order of magnitude caused by the conversion of unit systems at both ends of the formula, which is introduced by the unit conversion coefficient. In the derivation of this formula, since one liter is equivalent to one million cubic millimeters, one minute is equivalent to a time span of sixty seconds, and one square centimeter is equivalent to one hundred square millimeters, the difference in the number systems of these three is fixed as one-sixth of one hundred after division and normalization, which is approximately equal to 16.67.

[0053] After substituting the area and flow rate into this constant for multiplication correction in the formula, the result is the characteristic air permeability. The data encoding module then configures a fabric label without significant directionality for the current sample, and encapsulates this qualitative label along with the calculated characteristic air permeability value into the communication output protocol stack, rendering it to the peripheral screen or printing port to complete the issuance of the basic morphological test report.

[0054] Conversely, if the comparator determines in the calculation process that the comprehensive directionality index is greater than or equal to the preset directionality threshold, then from the perspective of physical stress analysis, it is confirmed that the sample belongs to an asymmetric composite fabric. The pore morphology on both sides of this type of fabric exhibits diametrically opposite expansion and closure damping characteristics under unidirectional pressure. The processing program must cut off the mean fusion path and perform completely isolated parallel calculations on the data from both sides. The system's core extracts all values ​​from the retained forward flow sequence and calculates their average values ​​separately. It directly reuses the same area comparison architecture and unit conversion coefficient mentioned above, bypassing the global fusion step, and independently maps this basic mean value to a forward air permeability value. The software execution stack then horizontally reads all values ​​from the reverse flow sequence, calculates their average values ​​separately, and performs calculations on the same side of the equals sign to map the reverse air permeability value.

[0055] After completing the independent dimension air permeability calculation, the system uses a logic unit to compare the absolute magnitude of the forward and reverse air permeability values. From a fluid dynamics perspective, when the lateral airflow penetration volume ratio is larger under the same constant pressure, it intuitively demonstrates that the compressive flow resistance encountered when the airflow penetrates the fabric's internal microfiber pore structure from the surface is actually smaller. Based on this correlation, the algorithm module extracts the initial wind- and pressure-bearing plane corresponding to the larger of the two values, modifies its attribute enumeration bit in the report's memory dictionary, and defines it as the easily permeable side identifier. Simultaneously, the main control program writes a prominent directional fabric label with a mandatory warning effect to the current sample. Finally, the communication bus stacks and packages the directional label text, the two independently calculated forward and reverse air permeability values, the easily permeable side identifier used to guide fabric layout and garment sewing, and the comprehensive directional index providing overall decision support for the initial state into a single data frame to generate an air permeability test report, which is then distributed and transmitted externally.

[0056] It should be noted that the interval and threshold sizes are set for ease of comparison. The size of the threshold depends on the amount of sample data and the base number set by those skilled in the art for each set of sample data, as long as it does not affect the proportional relationship between the parameter and the quantized value. Furthermore, the above formulas are all dimensionless calculations, and the formulas are derived from software simulations using a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0057] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0058] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

[0059] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A smart detection and data management system for breathable fabrics based on the constant pressure difference method, characterized in that, include: The airflow switching test module is used to control the airflow switching mechanism to apply airflow in an alternating sequence of forward and reverse directions while maintaining a preset target pressure difference for a preset odd number of cyclic tests in a single fixed clamping state of the sample. The data acquisition module is used to extract the test area of ​​the sample during the cyclic test and record the forward steady-state flow rate after the forward airflow reaches the target pressure difference and stabilizes, forming a forward flow rate sequence; it also records the reverse steady-state flow rate after the reverse airflow reaches the target pressure difference and stabilizes, forming a reverse flow rate sequence; and it records the time elapsed from the application of the forward airflow until the flow rate fluctuation rate falls below the preset fluctuation threshold, forming a forward stable time series; and it also records the time elapsed from the application of the reverse airflow until the flow rate fluctuation rate falls below the preset fluctuation threshold, forming a reverse stable time series. The drift determination module is used to extract the first and last positive steady-state flows in the positive flow sequence, calculate the absolute value of the difference between the first and last positive steady-state flows, and determine the flow drift rate by the ratio of the absolute value of the difference to the first positive steady-state flow; and determine whether the flow drift rate is greater than the preset damage extreme value limit. The termination output module is used to interrupt the test and output a structural instability termination command when the flow drift rate exceeds the preset damage extreme limit. The directionality calculation module is used to calculate the comprehensive directionality index based on the forward flow sequence, reverse flow sequence, forward stable time series and reverse stable time series when the flow drift rate is not greater than the preset damage extreme limit. The results generation module is used to compare the comprehensive directional index with the preset directional limit threshold, and generate and output an air permeability test report based on the comparison results and the test area.

2. The intelligent detection and data management system for breathable fabrics based on the constant pressure difference method according to claim 1, characterized in that, The comprehensive directionality index is calculated based on forward flow series, reverse flow series, forward stable time series, and reverse stable time series, including: The static flow asymmetry is calculated from the forward and reverse flow sequences. The dynamic response lag ratio is calculated from the forward stable time series and the backward stable time series. Obtain the system's preset primary and secondary weight parameters; The flow distribution assessment value is obtained by multiplying the sovereign re-parameter with the static flow asymmetry. The deformation time evaluation value is obtained by multiplying the secondary weight parameter with the dynamic response lag ratio. The flow distribution assessment value and the deformation time assessment value are added together, and the result is used as the comprehensive directionality index.

3. The intelligent detection and data management system for breathable fabrics based on the constant pressure difference method according to claim 2, characterized in that, The static flow asymmetry is calculated from the forward and reverse flow sequences, including: The average forward flow rate is obtained by calculating the average of all values ​​in the forward flow sequence, and the average reverse flow rate is obtained by calculating the average of all values ​​in the reverse flow sequence. Calculate the absolute value of the difference between the forward average flow rate and the reverse average flow rate; Compare the magnitudes of the forward average flow and the reverse average flow, and extract the largest value of the two as the extreme value benchmark flow. Divide the absolute value of the difference by the extreme baseline flow rate, and use the calculated quotient as the static flow asymmetry.

4. The intelligent detection and data management system for breathable fabrics based on the constant pressure difference method according to claim 2, characterized in that, The dynamic response lag ratio is calculated from the forward-stable and backward-stable time series, including: The forward average settling time is obtained by calculating the average of all values ​​in the forward stable time series, and the reverse average settling time is obtained by calculating the average of all values ​​in the reverse stable time series. Calculate the absolute value of the difference between the forward average settling time and the reverse average settling time; Compare the magnitudes of the forward average settling time and the reverse average settling time, and extract the one with the largest value as the extreme response time. Divide the absolute value of the difference by the extreme response time, and use the calculated ratio as the dynamic response lag ratio.

5. The intelligent detection and data management system for breathable fabrics based on the constant pressure difference method according to claim 2, characterized in that, Obtain the system's preset primary and secondary weight parameters, including: Extract the global minimum stable time from the forward stable time series and the backward stable time series; The global minimum settling time is compared with the preset rigid reference time, and the excess value between the two is obtained. Divide the excess value by the set adjustment step size coefficient to generate a dynamic offset; Add the dynamic offset to the preset basic dynamic weight parameters to obtain the secondary weight parameters; The main weight parameter is calculated by subtracting the secondary weight parameter from the number 1.

6. The intelligent detection and data management system for breathable fabrics based on the constant pressure difference method according to claim 1, characterized in that, Record the duration from the application of positive airflow until the flow fluctuation rate falls below the preset fluctuation threshold each time to form a positive stable time series; Record the forward steady-state flow rate after each forward airflow reaches the target pressure difference and stabilizes, forming a forward flow rate sequence, including: After each time the airflow switching mechanism applies positive airflow and the pressure difference reaches the target pressure difference, the instantaneous flow rate value is continuously extracted according to the preset sampling period; Construct a sliding time window with the current sampling time as the endpoint, and calculate the relative standard deviation of all instantaneous flow values ​​within the sliding time window as the flow fluctuation rate at the current time. When the flow fluctuation rate is lower than the preset fluctuation threshold for multiple consecutive sampling periods, the current sampling time is determined as the stable arrival point. Extract the time span from the start of applying the positive airflow to the determination of the stable arrival point as the positive stability duration of the current round, and add the positive stability duration to the positive stability time series; Extract the arithmetic mean of all instantaneous flow values ​​within the sliding time window as the positive steady-state flow for the current cycle, and add the positive steady-state flow to the positive flow sequence.

7. The intelligent detection and data management system for breathable fabrics based on the constant pressure difference method according to claim 1, characterized in that, If the flow drift rate exceeds the preset damage limit, the test is interrupted and a structural instability termination command is output, including: When the flow drift rate is determined to be greater than the preset damage extreme limit, the forward airflow is cut off and the subsequent cycle test is terminated. Extract the absolute value of the first and last ranges of two adjacent tests based on the sorting of the positive flow sequence; If the absolute value of the first and last ranges is not greater than the preset mutation threshold, the sample is determined to have undergone progressive fatigue damage. If the absolute value of the first and last ranges is greater than the preset mutation threshold, the sample is determined to have suffered transient fracture damage. The progressive fatigue damage results and transient fracture damage are converted into diagnostic logs, which are then encapsulated into structural instability termination instructions and output.

8. The intelligent detection and data management system for breathable fabrics based on the constant pressure difference method according to claim 1, characterized in that, The comprehensive directional index is compared with a preset directional threshold. Based on the comparison results and the test area, a breathability test report is generated and output, including: When the comprehensive directionality index is less than the preset directionality limit threshold, all values ​​of the forward flow sequence are extracted and the average value is taken as the first flow mean, and all values ​​of the reverse flow sequence are extracted and the average value is taken as the second flow mean. Calculate the sum of the first average flow rate and the second average flow rate, and divide the sum by two to obtain the global baseline flow rate; The characteristic air permeability is calculated by dividing the global baseline flow rate by the test area and multiplying it by the internally preset unit conversion factor. The sample was identified as a fabric label without significant directional properties, and the characteristic air permeability was combined with the fabric label without significant directional properties to generate and output an air permeability test report.

9. The intelligent detection and data management system for breathable fabrics based on the constant pressure difference method according to claim 8, characterized in that, The generation of the breathability test report also includes: When the comprehensive directionality index is not less than the preset directionality limit threshold, extract all values ​​of the positive flow sequence, calculate the average value, divide it by the test area and multiply it by the preset unit dimension conversion factor to obtain the positive air permeability value. Extract all values ​​from the reverse flow sequence, calculate the average value, divide it by the test area, and multiply it by the unit conversion factor to obtain the reverse air permeability value. Compare the forward breathability value with the reverse breathability value, extract the one with the larger value, and mark the corresponding fabric side attribute as the breathable side identifier. The sample is identified as a fabric with a significant directional label. The significant directional fabric label, the forward air permeability value, the reverse air permeability value, the easily breathable side label, and the comprehensive directional index are packaged together to generate and output an air permeability test report.

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