Airbag static comprehensive test device and method thereof

Abstract

The application discloses a safety airbag static comprehensive test device and method, and belongs to the technical field of automobile safety system testing, which comprises the following steps: S1, constructing a multi-dimensional heterogeneous test environment comprising a physical sensing group and a quadrature double optical path imaging; S2, performing microsecond-level timing adaptive calibration to obtain system delay difference; S3, based on ignition triggering and delay compensation, synchronously collecting airbag quadrature dynamic projection and transient pressure; S4, obtaining instantaneous volume through three-dimensional reconstruction, and combining a pressure curve to perform phase correction and coupling analysis, so as to realize quantitative evaluation of airbag deployment quality. The application ensures that the image frames recorded by the double optical path imaging group and the data points recorded by the gas pressure sensor are strictly aligned in physical time, significantly reduces data dislocation caused by equipment response difference, and provides a precise timing reference for fluid-structure coupling analysis.

Description

Technical Field

[0001] This invention relates to the field of automotive safety system testing, specifically to a static comprehensive testing device and method for airbags. Background Technology

[0002] With the development and upgrading of automotive passive safety technology, a highly dynamic, multi-dimensional physical field testing environment will be constructed under typical static comprehensive airbag testing scenarios. Airbag deployment failure response exhibits significant transient explosiveness and complex fluid-structure interaction characteristics, making traditional testing methods based on single visual observation or single electrical signal monitoring and independent analysis of discrete data inadequate. Traditional testing methods suffer from a disconnect between the spatiotemporal reference of visual images and physical quantity data, increasing the risk of misjudging or missing hidden defects, severely impacting the accurate assessment of airbag deployment quality and the reliability verification of passive safety systems.

[0003] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a static comprehensive testing device and method for airbags to solve the problems mentioned in the background art. The technical solution of this invention includes:

[0005] S1. Constructing a multidimensional heterogeneous test environment: A rigid test bench, a universal fixture, a dual-optical-path imaging group, a physical quantity sensing group, and a heterogeneous data processor are set up. The universal fixture is fixed at the center of the rigid test bench. The dual-optical-path imaging group includes a first high-speed camera and a second high-speed camera. The first high-speed camera and the second high-speed camera are located in the X-axis direction and the Y-axis direction of the universal fixture, respectively, and their optical axes are orthogonally distributed and intersect at the center point of the airbag. The physical quantity sensing group includes a gas pressure sensor and a Hall current sensor.

[0006] S2. Perform microsecond-level time-adaptive calibration: The heterogeneous data processor sends pulse signals to the synchronous strobe lights located within the common field of view of the first high-speed camera and the second high-speed camera, respectively obtains the visual zero point and physical zero point, calculates the system delay difference and stores it in the system parameter library;

[0007] S3. Multidimensional heterogeneous data synchronous acquisition: When the Hall current sensor detects that the ignition current exceeds the set threshold, the heterogeneous data processor compensates for the trigger command according to the system delay difference, controls the dual-optical-path imaging group to record the dynamic projection contour flow of the airbag on two orthogonal planes, and simultaneously controls the gas pressure sensor to record the transient pressure curve.

[0008] S4. Morphology-Pressure Coupling Feature Analysis: The dynamic projection contour flow is reconstructed in three dimensions to obtain the instantaneous equivalent volume. Based on the fluid-structure interaction causal chain, the transient pressure curve and the instantaneous equivalent volume are phase-corrected and coupled to quantitatively evaluate the airbag deployment quality.

[0009] Preferably, the body of the universal clamp seat has an L-shaped airflow channel inside, with one end connected to the central air vent on the upper surface of the seat body and the other end connected to the side wall of the seat body;

[0010] In step S1, the gas pressure sensor is installed on the side wall of the universal fixture seat and is connected to the jet outlet gas path of the airbag to be tested through the L-shaped airflow channel.

[0011] In step S3, the gas pressure sensor directly collects the instantaneous inflation pressure data at the airbag inlet through the L-shaped airflow channel.

[0012] Preferably, the specific implementation of step S2 includes:

[0013] Extract the timestamp of the first frame when the synchronous strobe light illuminates, captured by the first high-speed camera or the second high-speed camera, and use it as the visual zero point;

[0014] The rising edge of the waveform of the pulse signal sensed by the Hall current sensor is extracted and used as the physical zero point;

[0015] Calculate the time difference between the visual zero point and the physical zero point, and define this difference as the inherent transmission delay between the vision system and the electrical measurement system.

[0016] Preferably, the method for three-dimensional reconstruction of the dynamic projection contour flow in step S4 includes:

[0017] The video frames captured by the first high-speed camera and the second high-speed camera are binarized to extract the edge contour of the airbag.

[0018] Based on the principle of orthogonal visual geometry, the airbag edge contours from two perspectives are stretched and intersected in a virtual three-dimensional space to reconstruct the instantaneous equivalent volume of the airbag at each millisecond.

[0019] The instantaneous equivalent volume at consecutive time points is differentiated to obtain the instantaneous expansion rate curve of the airbag.

[0020] Preferably, the specific steps for phase correction and coupling analysis in step S4 include:

[0021] The transient pressure curve is subjected to time differentiation to obtain the instantaneous pressure change rate curve;

[0022] Within a set sliding time window, the translation time corresponding to the highest overlap between the instantaneous pressure change rate curve and the instantaneous expansion rate curve is calculated and defined as the fluid-structure response hysteresis time.

[0023] The original data is aligned based on the fluid-structure response hysteresis time, and the pressure-volume coupling index is calculated. The pressure-volume coupling index characterizes the volume expansion driven by a unit pressure change.

[0024] Preferably, step S4 further includes the step of identifying unfolding obstruction defects based on the fluid-structure interaction hysteresis time:

[0025] If the transient pressure continues to rise during a certain period of time, but the instantaneous equivalent volume remains unchanged or increases very slowly, the duration of that period is determined.

[0026] If the duration of this period significantly exceeds the preset fault judgment threshold, it is determined that the airbag has an obstruction to deployment or an internal adhesion defect.

[0027] If the duration of this period does not exceed the fluid-solid response hysteresis time, it is determined to be a cold-state fabric hysteresis characteristic.

[0028] The preset fault determination threshold is set based on the fluid-structure response hysteresis time multiplied by a determination tolerance coefficient.

[0029] Preferably, step S4 further includes the step of identifying leakage defects based on the adiabatic expansion theory benchmark:

[0030] The initial total energy is obtained based on the amount of explosives in the gas generator. Combined with the instantaneous equivalent volume reconstructed in real time, the theoretical benchmark of adiabatic expansion under ideal conditions is deduced based on the principle of energy conservation.

[0031] The measured transient pressure curve is compared with the adiabatic expansion theoretical benchmark.

[0032] If the measured rate of decrease of transient pressure is faster than the theoretical benchmark of adiabatic expansion, and the instantaneous equivalent volume growth stops, then the airbag fabric is determined to be damaged or the seam is leaking.

[0033] Preferably, step S4 further includes a step of identifying material aging defects based on the pressure-volume coupling index:

[0034] Preset standard airbag pressure-volume coupling index benchmark value;

[0035] The calculated pressure-volume coupling index is compared with the benchmark value of the standard airbag pressure-volume coupling index.

[0036] If the pressure-volume coupling index is lower than the preset material aging judgment threshold, and the transient pressure is within the normal range, then the airbag fabric material is determined to have a risk of hardening, deterioration, or elastic failure.

[0037] A static comprehensive testing device for airbags, comprising:

[0038] A rigid test bench provides a test reference plane, with a universal fixture seat fixed at its center. The universal fixture seat has an L-shaped airflow channel inside.

[0039] The dual-optical-path imaging group includes a first high-speed camera and a second high-speed camera that are orthogonally distributed to capture the shape of the airbag.

[0040] The physical quantity sensing group includes a gas pressure sensor mounted on the side wall of the universal fixture seat and a Hall current sensor mounted on the ignition wire.

[0041] A heterogeneous data processor, connected to the above components, is used to perform timing calibration, data acquisition, and coupled feature analysis.

[0042] This invention provides an improved static comprehensive testing device and method for airbags, which has the following improvements and advantages compared with the prior art:

[0043] 1. This solution addresses the inconsistency in response between optical and electrical systems by constructing a multidimensional heterogeneous experimental environment and performing microsecond-level adaptive timing calibration. The heterogeneous data processor acquires the visual zero point and physical zero point by sending pulse signals to the synchronous strobe lamp, calculates the system delay difference, and stores it in the system parameter library. When the experiment is triggered, this delay difference is used to compensate for the timing of the command, ensuring that the image frames recorded by the dual-optical-path imaging group and the data points recorded by the gas pressure sensor are strictly aligned in physical time. This significantly reduces data misalignment caused by differences in device response and provides an accurate timing reference for fluid-structure interaction analysis.

[0044] 2. This solution optimizes the pressure signal acquisition path through an L-shaped airflow channel within the universal fixture base. The gas pressure sensor is directly mounted on the side wall of the universal fixture base and connected to the air outlet of the airbag via an extremely short L-shaped airflow channel. This structural design avoids the deformation buffering that may occur with traditional external hose connections, significantly reducing the pressure wave delay and amplitude attenuation caused by long tubing. This allows the sensor to acquire instantaneous inflation pressure data at the airbag inlet without damage, accurately reflecting the airbag's pressure condition.

[0045] 3. By calculating the fluid-structure response hysteresis time, the transient pressure change rate curve and the instantaneous expansion rate curve are phase-matched. If the pressure continues to rise but the duration of the volume growth stagnation significantly exceeds this hysteresis time, it can be accurately determined that the airbag has obstructed deployment or internal adhesion defects, effectively distinguishing the normal cold-state fabric hysteresis characteristics. Based on the principle of energy conservation, an adiabatic expansion theoretical benchmark is constructed. By comparing the measured transient pressure curve with the theoretical benchmark, it can keenly detect working conditions where the pressure drop rate is abnormally fast than the theoretical value and the volume does not increase. Thus, airbag fabric damage or seam leakage can be identified without water testing. By calculating the pressure-volume coupling index and comparing it with the standard airbag elastic modulus benchmark value, the hardness or compliance of the airbag can be digitized. When the coupling index is significantly low, it can be determined that the airbag fabric material has the risk of hardening deterioration or elastic failure, realizing in-depth diagnosis of the material's physical properties. Attached Figure Description

[0046] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0047] Figure 1 This is a schematic diagram of the overall structure of the device;

[0048] Figure 2 This is a schematic diagram of a general-purpose fixture base and its overall connection structure;

[0049] Figure 3 This is a schematic diagram of the Hall current sensor.

[0050] Figure 4 This is a schematic diagram of the process flow of the method of the present invention.

[0051] In the figure: 100, rigid test bench; 120, universal fixture base; 200, dual-optical-path imaging group; 230, synchronous strobe lamp; 300, physical quantity sensing group; 310, gas pressure sensor; 320, Hall current sensor; 400, heterogeneous data processor. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0053] Example 1:

[0054] Please see Figure 1-4 This invention provides a static comprehensive test method for airbags, comprising:

[0055] S1. Constructing a multidimensional heterogeneous test environment: A rigid test bench 100, a universal fixture 120, a dual-optical-path imaging group 200, a physical quantity sensing group 300, and a heterogeneous data processor 400 are set up. The universal fixture 120 is fixed at the center of the rigid test bench 100. The dual-optical-path imaging group 200 includes a first high-speed camera and a second high-speed camera. The first high-speed camera and the second high-speed camera are located in the X-axis direction and the Y-axis direction of the universal fixture 120, respectively, and their optical axes are orthogonally distributed and intersect at the center point of the airbag. The physical quantity sensing group 300 includes a gas pressure sensor 310 and a Hall current sensor 320.

[0056] S2. Perform microsecond-level time-adaptive calibration: The heterogeneous data processor 400 sends pulse signals to the synchronous strobe lamp 230 located within the common field of view of the first high-speed camera and the second high-speed camera, respectively, to obtain the visual zero point and the physical zero point, calculate the system delay difference and store it in the system parameter library.

[0057] S3. Multidimensional heterogeneous data synchronous acquisition: When the Hall current sensor 320 detects that the ignition current exceeds the set threshold, the heterogeneous data processor 400 compensates for the trigger command according to the system delay difference, controls the dual-optical imaging group 200 to record the dynamic projection contour flow of the airbag on two orthogonal planes, and controls the gas pressure sensor 310 to record the transient pressure curve.

[0058] S4. Morphology-Pressure Coupling Feature Analysis: The dynamic projected contour flow is reconstructed in three dimensions to obtain the instantaneous equivalent volume. Based on the fluid-structure interaction causal chain, the transient pressure curve and the instantaneous equivalent volume are phase-corrected and coupled to quantitatively evaluate the airbag deployment quality.

[0059] In this embodiment, a static comprehensive test method for airbags mainly solves the problem that single visual observation or single electrical measurement data are fragmented on the time axis in the prior art; the multidimensional heterogeneous test environment serves as the physical basis, and the rigid test bench 100 provides stable support against impact, avoiding displacement of the equipment due to the explosion impact. The universal fixture 120 is located at the core, working in conjunction with the dual-optical-path imaging group 200 to simultaneously observe from two orthogonal directions, the X and Y axes, enabling the acquisition of three-dimensional information about the airbag's deployment in space. The physical quantity sensing group 300 is responsible for capturing invisible internal pressure and current signals. The heterogeneous data processor 400 acts as the central hub, performing microsecond-level adaptive timing calibration to calculate the system delay difference between the two, taking into account the physical characteristics of slow imaging by optical devices and fast sensing by electrical devices. When the experiment is triggered, the heterogeneous data processor 400 uses this delay difference to compensate for the time of the command, ensuring that the image frames recorded by the dual-optical-path imaging group 200 and the data points recorded by the gas pressure sensor 310 are strictly aligned in physical time. Through morphology-pressure coupling feature analysis, the volume change transformed from the dynamic projection contour flow is combined with the transient pressure curve to reveal the intrinsic physical relationship between pressure-driven volume expansion during airbag deployment, thereby achieving a comprehensive quantitative evaluation of the airbag deployment quality.

[0060] The general-purpose clamp holder 120 has an L-shaped airflow channel inside its body, with one end connected to the central air vent on the upper surface of the holder and the other end connected to the side wall of the holder.

[0061] The L-shaped airflow channel is in Figure 2 Although not explicitly cut open, its path is defined as a connecting channel that extends vertically downward from the center of the top surface of the base and then bends horizontally toward the side wall interface.

[0062] In step S1, the gas pressure sensor 310 is installed on the side wall of the universal fixture seat 120 and is connected to the jet outlet gas path of the airbag to be tested through the L-shaped airflow channel.

[0063] In step S3, the gas pressure sensor 310 directly collects the instantaneous inflation pressure data at the airbag inlet through the L-shaped airflow channel.

[0064] In this embodiment, the universal clamp base 120 is designed not only for clamping but also to solve the problem of pressure signal transmission distortion. The universal clamp base 120 has an L-shaped airflow channel internally, which is machined through drilling inside the base body, avoiding deformation buffering that might occur with external hose connections. The gas pressure sensor 310 is directly screwed into the interface on the side wall of the universal clamp base 120, forming a very short air path connection with the airbag nozzle on the upper surface of the base body through the L-shaped airflow channel. At the moment the gas generator detonates, as high-pressure gas fills the airbag, a portion of the gas pressure is transmitted to the sensing diaphragm of the gas pressure sensor 310 without attenuation. This structural design significantly reduces the pressure wave delay and amplitude attenuation caused by the long conduit, ensuring that the instantaneous inflation pressure data collected by the gas pressure sensor 310 accurately reflects the pressure conditions at the airbag inlet, providing high-fidelity raw data support for subsequent accurate fluid-structure interaction analysis.

[0065] The specific implementation methods of step S2 include:

[0066] Extract the timestamp of the first frame when the synchronized strobe light 230 lights up, captured by the first high-speed camera or the second high-speed camera, and use it as the visual zero point;

[0067] Extract the rising edge of the pulse signal sensed by Hall current sensor 320 as the physical zero point;

[0068] Calculate the time difference between the visual zero point and the physical zero point, and define this difference as the inherent transmission delay between the vision system and the electrical measurement system.

[0069] In this embodiment, the microsecond-level timing adaptive calibration step aims to significantly reduce the response time difference between heterogeneous sensor devices; the heterogeneous data processor 400 sends a unified trigger command to the synchronous strobe lamp 230 in the system; the first high-speed camera or the second high-speed camera, as a visual capture unit, has an inherent delay in its photosensitive chip from receiving light signals to generating digital images, so the image processing algorithm identifies the frame in the picture where the synchronous strobe lamp 230 is lit and extracts the visual zero point at that moment;

[0070] To achieve microsecond-level precision, the heterogeneous data processor 400 reads the hardware latch clock signal at the exposure moment of the high-speed camera, rather than just reading the system transmission time of the image frame, thereby ensuring that the time resolution of the visual zero point reaches the microsecond level.

[0071] Meanwhile, the Hall current sensor 320, as an electromagnetic induction element, has an extremely fast response speed, capturing the physical zero point the instant the same trigger pulse current signal is detected. The heterogeneous data processor 400 performs difference calculations between the visual zero point and the physical zero point to quantify the inherent transmission delay between the visual system and the electrical measurement system, i.e., the system delay difference. This parameter is not fixed but is finely adjusted according to the equipment status and stored in the system parameter library. This allows each subsequent airbag deployment test to be precisely time-aligned based on the current hardware status, significantly reducing data misalignment caused by differences in equipment response.

[0072] The method for 3D reconstruction of the dynamic projection contour flow in step S4 includes:

[0073] The video frames captured by the first high-speed camera and the second high-speed camera are binarized to extract the edge contour of the airbag.

[0074] Based on the principle of orthogonal visual geometry, the airbag edge contours from two perspectives are stretched and intersected in a virtual three-dimensional space to reconstruct the instantaneous visual outer envelope volume of the airbag at every millisecond, which serves as an approximate representation of the instantaneous equivalent volume.

[0075] The instantaneous equivalent volume at consecutive moments is differentiated to obtain the instantaneous expansion rate curve of the airbag.

[0076] In this embodiment, the three-dimensional reconstruction process of the dynamic projection contour flow is the key to converting planar images into spatial data. The heterogeneous data processor 400 analyzes the high frame rate video streams transmitted from the first high-speed camera and the second high-speed camera frame by frame, performs binarization processing through image processing methods such as grayscale thresholding, separates the airbag area from the background, and accurately extracts the edge contour of the airbag. Based on the principle of orthogonal visual geometry, the system assumes that the contours of the two orthogonal viewpoints represent the projection constraints of the airbag in the X-axis and Y-axis directions, respectively. In the virtual three-dimensional coordinate system, the two planar contours are stretched along their respective normal directions to form cylinders, and the common intersection of the two cylinders is calculated to approximately fit the instantaneous equivalent volume of the airbag at this moment. The instantaneous visual outer envelope volume is the instantaneous equivalent volume described in this invention.

[0077] It should be noted that the instantaneous equivalent volume calculated by this method is essentially the apparent outer envelope volume of the airbag. Although the calculation logic ignores the possible local depression features on the surface of the airbag, during the high-pressure inflation phase of airbag deployment, the airbag as a whole exhibits an outward convex trend, and the rate of change of its apparent outer envelope volume is highly consistent with the rate of change of its actual internal volume. Therefore, this approximate fitting data is sufficient to meet the calculation requirements for the volume change trend, i.e., the first derivative, in subsequent fluid-structure interaction analysis. This process is repeated for each frame of image to form a volume sequence that changes over time. The heterogeneous data processor 400 further differentiates this volume sequence with respect to time, i.e., performs differential calculations, to obtain the instantaneous expansion rate curve characterizing the speed of airbag deployment. This allows the spatial dynamics of the airbag's interior to be deduced based solely on external observations, providing the necessary kinematic parameters for subsequent coupling analysis with pressure data.

[0078] The specific steps for phase correction and coupling analysis in step S4 include:

[0079] The transient pressure curve is processed by time differentiation to obtain the instantaneous pressure change rate curve;

[0080] Within a set sliding time window, the translation time corresponding to the highest overlap between the instantaneous pressure change rate curve and the instantaneous expansion rate curve is calculated and defined as the fluid-structure response hysteresis time.

[0081] Align the original data based on the fluid-structure response hysteresis time and calculate the pressure-volume coupling index, which characterizes the volume expansion driven by a unit pressure change.

[0082] The specific calculation logic of this index is as follows: Select the linear elastic range before the airbag deploys to the saturation stage, and calculate the instantaneous equivalent volume within this range. Transient pressure Linear regression analysis yields the slope k, which is the pressure-volume coupling index, and its physical dimension corresponds to volume compliance.

[0083] In this embodiment, phase correction and coupling analysis are used to reveal the physical causal mechanism of airbag deployment. The heterogeneous data processor 400 performs numerical differentiation on the transient pressure curve to obtain an instantaneous pressure change rate curve reflecting the intensity of pressure fluctuations. Physically, there is a small time difference between the gas pressure build-up process (the cause) and the fabric expansion process (the result), influenced by fabric inertia and folding friction. Within a sliding time window, the system performs cross-correlation matching between the instantaneous pressure change rate curve and the aforementioned instantaneous expansion rate curve to find the moment when their waveform characteristics best match.

[0084] The specific matching algorithm uses a normalized cross-correlation function for calculation. The system calculates the instantaneous pressure change rate curve within a sliding time window. With instantaneous expansion rate curve cross-correlation coefficient ; and Zero-mean processing is required before calculation. The calculation logic is as follows:

[0085]

[0086] in, The system iterates through the set time window to attempt translation. When the maximum value is reached, the corresponding The value is locked as the fluid-structure interaction hysteresis time, thus ensuring the uniqueness and accuracy of the alignment time determination through mathematical extrema; the displacement at which the two reach optimal matching is determined as the fluid-structure interaction hysteresis time. Using this time parameter, the system realigns the pressure and volume data on the time axis, significantly reducing the interference of physical conduction delay. Based on this, the system calculates the pressure-volume coupling index, which reflects the airbag volume response capability under specific pressure, i.e., the volume expansion driven by a unit pressure change, thereby digitizing the airbag's stiffness or compliance for evaluating the airbag's inflation and deployment efficiency.

[0087] Step S4 also includes the step of identifying unfolding obstructed defects based on the fluid-structure response hysteresis time:

[0088] If the transient pressure continues to rise during a certain period of time, but the instantaneous equivalent volume remains unchanged or increases very slowly, then the duration of that period is determined.

[0089] The system sets a judgment tolerance coefficient, such as 1.5 to 2 times the fluid-structure response hysteresis time, as a safety boundary;

[0090] If the duration of this period significantly exceeds the preset fault judgment threshold, it is determined that the airbag has an obstruction to deployment or an internal adhesion defect.

[0091] If the duration of this period does not exceed the fluid-solid response hysteresis time, it is determined to be a cold-state fabric hysteresis characteristic;

[0092] The preset fault judgment threshold is set based on the fluid-structure response hysteresis time multiplied by a judgment tolerance coefficient.

[0093] In this embodiment, the fluid-structure response hysteresis time is not only a calibration parameter, but also a benchmark for judging product defects. In actual test scenarios, the heterogeneous data processor 400 monitors the airbag deployment process in real time. If it is found that the transient pressure is constantly increasing, it means that a large amount of gas is being injected, but at the same time the instantaneous equivalent volume hardly changes, which indicates that the airbag does not expand synchronously with the pressure. The system then calculates the duration of this abnormal state. If the duration of this period is only brief and does not exceed the pre-calculated fluid-structure response hysteresis time, it is usually because the fabric has a certain physical inertia in a low-temperature or folded state, which is a normal cold-state fabric hysteresis characteristic. This is attributed to the initial response time required for the fabric material to overcome static friction and intermolecular van der Waals forces in a low-temperature or folded high-density state. After this hysteresis period, the airbag will then deploy normally. However, if this stagnation significantly exceeds the normal physical hysteresis range, it indicates that there is abnormal resistance in the internal structure. Based on this, the system determines that the airbag has obstructed deployment or internal adhesion defects. This judgment logic based on physical benchmarks avoids misjudgments that may be caused by visual observation alone and effectively distinguishes between normal physical delays and pathological mechanical failures.

[0094] Step S4 also includes the step of identifying leakage defects based on the adiabatic expansion theory benchmark:

[0095] The initial total energy is obtained based on the amount of explosives in the gas generator. Combined with the instantaneous equivalent volume reconstructed in real time, the theoretical benchmark of adiabatic expansion under ideal conditions is deduced based on the principle of energy conservation.

[0096] The measured transient pressure curves were compared with the theoretical benchmark of adiabatic expansion.

[0097] If the measured transient pressure drop rate is faster than the theoretical benchmark for adiabatic expansion, and is accompanied by a halt in the instantaneous equivalent volume growth, then the airbag fabric is determined to be damaged or the seam is leaking.

[0098] In this embodiment, the adiabatic expansion theoretical benchmark is established to identify airtightness issues without the need for water testing. The heterogeneous data processor 400 reads the specifications of the gas generator and calculates the initial total energy it can release based on the propellant charge; specifically, the system retrieves pre-stored propellant characteristic parameters of the gas generator to calculate the initial total energy. Theoretical specific energy of propellants and combustion efficiency coefficient Derived from gas generator product specifications or closed-loop burst test results; adiabatic index Usually taken Standard fully deployed volume of airbag design It is derived from airbag design drawings or standard specifications; its calculation logic is as follows:

[0099]

[0100] in, The charge mass of the gas generator is provided by the specifications. The theoretical specific energy of the propellant is the heat released by the complete combustion of a unit mass of gunpowder. This is the combustion efficiency coefficient determined by a closed-circuit test. The system is based on this total energy, combined with the ideal gas law and the adiabatic process equations. ,in This is the adiabatic index, usually taken as 1.4. As a constant, a theoretical pressure-volume relationship curve is constructed.

[0101] Where, constant The determination logic is as follows: the system is based on the initial total energy. The maximum volume of the gas generator design (Standard fully deployed volume of airbag design) and adiabatic index The calculation shows that the airbag reaches its ideal state. Theoretical maximum adiabatic pressure at that time The system solves this by simultaneously applying the ideal gas law. and adiabatic process equations Establish a theoretical model, in which Based on this, the instantaneous equivalent volume of real-time reconstruction is utilized. By deducing the theoretical pressure reference curve for adiabatic expansion under ideal conditions, :

[0102]

[0103] in, The standard fully deployed volume of the airbag is designed to establish a theoretical baseline for adiabatic attenuation that is completely independent of measured pressure values.

[0104] By combining the instantaneous equivalent volume obtained through visual reconstruction, the system uses the thermodynamic energy conservation formula to derive a theoretical baseline curve for adiabatic expansion that pressure should follow as volume changes in an ideal closed system without gas leaks. Subsequently, the system dynamically overlays and compares the measured transient pressure curve with this theoretical curve. In the later stages of airbag deployment, if the measured pressure value decays extremely rapidly, faster than the theoretically calculated baseline value, and simultaneously the instantaneous equivalent volume does not increase further, ruling out pressure drop due to volume increase, this indicates only a loss of gas mass. Based on this, the system determines that the airbag fabric is damaged or there is a leak at the seam. This method, through logical deduction from a physical model, achieves non-contact diagnosis of hidden leak defects.

[0105] Step S4 also includes the step of identifying material aging defects based on the pressure-volume coupling index:

[0106] Preset standard airbag pressure-volume coupling index benchmark value;

[0107] The calculated pressure-volume coupling index is compared with the benchmark value of the standard airbag pressure-volume coupling index.

[0108] If the pressure-volume coupling index is significantly lower than the preset material aging judgment threshold, and the transient pressure is within the normal range, then the airbag fabric material is judged to have a risk of hardening, deterioration, or elastic failure.

[0109] In this embodiment, the pressure-volume coupling index is further applied to the in-depth evaluation of material properties. The system database stores the standard elastic modulus benchmark value of qualified new airbags, representing the elongation capacity of normal fabrics under pressure. When testing old or stocked airbags, the heterogeneous data processor 400 compares the measured pressure-volume coupling index with the benchmark value. If the measured index is found to be significantly lower than the benchmark value, for example, when the measured index is lower than 80% of the standard benchmark value, it means that the same pressure increment can only bring a small volume increment, that is, the airbag has become stiff. Under the premise of excluding insufficient pressure source, that is, the transient pressure is within the normal range, this abnormal increase in stiffness directly points to the change in the physical properties of the material itself. Based on this, the system determines that the airbag fabric material has the risk of hardening and deterioration or elastic failure. This logic enables the test device not only to detect whether the airbag can pop open, but also to further diagnose whether its material has aged, providing a deeper reference for product reliability.

[0110] Example 2:

[0111] Please see Figure 1-3 A static comprehensive testing device for airbags, comprising:

[0112] The rigid test bench 100 provides a test reference plane, and a universal fixture seat 120 is fixed at its center. The universal fixture seat 120 has an L-shaped airflow channel inside.

[0113] The dual-path imaging group 200 includes an orthogonally distributed first high-speed camera and a second high-speed camera for capturing airbag morphology.

[0114] The physical quantity sensing group 300 includes a gas pressure sensor 310 mounted on the side wall of the universal fixture 120 and a Hall current sensor 320 mounted on the ignition wire.

[0115] The heterogeneous data processor 400, connected to the above components, is used to perform timing calibration, data acquisition, and coupled feature analysis.

[0116] In this embodiment, the static comprehensive testing device for airbags embodies the aforementioned method. The rigid test bench 100 is constructed with a heavy-duty cast iron panel, ensuring high physical load-bearing capacity. The universal fixture seat 120 serves as a connection hub, and its internally integrated L-shaped airflow channel achieves an invisible connection of the air path, balancing sealing performance and sensor installation convenience. The first and second high-speed cameras in the dual-optical imaging group 200 are not placed directly, but are respectively mounted on a manual screw displacement stage. This mechanical structure supports micron-level fine position adjustment, ensuring precise orthogonality of the optical axes. The physical quantity sensing group 300, through the non-contact snap-fit ​​design of the Hall current sensor 320, can be easily connected to the ignition circuit to monitor trigger signals, forming a complete physical field monitoring network in conjunction with the gas pressure sensor 310. The heterogeneous data processor 400 aggregates all data streams through gigabit network cables and coaxial cables, executing core timing calibration, data acquisition, and coupling feature analysis algorithms. The components work together to build a comprehensive testing platform that integrates visual morphology and internal physical quantification, enabling a full-scale digital reproduction of airbag performance.

[0117] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A static comprehensive test method for airbags, characterized in that, include: S1. Constructing a multidimensional heterogeneous test environment: Set up a rigid test bench (100), a universal fixture (120), a dual-optical-path imaging group (200), a physical quantity sensing group (300), and a heterogeneous data processor (400). The universal fixture (120) is fixed at the center of the rigid test bench (100). The dual-optical-path imaging group (200) includes a first high-speed camera and a second high-speed camera. The first high-speed camera and the second high-speed camera are located in the X-axis direction and Y-axis direction of the universal fixture (120), respectively, and their optical axes are orthogonally distributed and intersect at the center point of the airbag. The physical quantity sensing group (300) includes a gas pressure sensor (310) and a Hall current sensor (320). S2. Perform microsecond-level time-adaptive calibration: The heterogeneous data processor (400) sends pulse signals to the synchronous strobe lamp (230) located within the common field of view of the first high-speed camera and the second high-speed camera, respectively obtains the visual zero point and physical zero point, calculates the system delay difference and stores it in the system parameter library; S3. Multidimensional heterogeneous data synchronous acquisition: When the Hall current sensor (320) detects that the ignition current exceeds the set threshold, the heterogeneous data processor (400) compensates the trigger command according to the system delay difference, controls the dual-optical imaging group (200) to record the dynamic projection contour flow of the airbag on two orthogonal planes, and controls the gas pressure sensor (310) to record the transient pressure curve. S4. Morphology-Pressure Coupling Feature Analysis: The dynamic projection contour flow is reconstructed in three dimensions to obtain the instantaneous equivalent volume. Based on the fluid-structure interaction causal chain, the transient pressure curve and the instantaneous equivalent volume are phase-corrected and coupled to quantitatively evaluate the airbag deployment quality. The method for three-dimensional reconstruction of the dynamic projection contour flow in step S4 includes: The video frames captured by the first high-speed camera and the second high-speed camera are binarized to extract the edge contour of the airbag. Based on the principle of orthogonal visual geometry, the airbag edge contours from two perspectives are stretched and intersected in a virtual three-dimensional space to reconstruct the instantaneous equivalent volume of the airbag at each millisecond. The instantaneous equivalent volume at consecutive time points is differentiated to obtain the instantaneous expansion rate curve of the airbag; The specific steps for phase correction and coupling analysis in step S4 include: The transient pressure curve is subjected to time differentiation to obtain the instantaneous pressure change rate curve; Within a set sliding time window, the translation time corresponding to the highest overlap between the instantaneous pressure change rate curve and the instantaneous expansion rate curve is calculated and defined as the fluid-structure response hysteresis time. The original data is aligned based on the fluid-structure response hysteresis time, and the pressure-volume coupling index is calculated. The pressure-volume coupling index characterizes the volume expansion driven by a unit pressure change. The calculation logic of the pressure-volume coupling index is as follows: Select the linear elastic interval before the airbag expands to the saturation stage, perform linear regression analysis on the transient pressure with the instantaneous equivalent volume in the interval, and the resulting slope is the pressure-volume coupling index.

2. The static comprehensive test method for airbags according to claim 1, characterized in that, The general-purpose clamp seat (120) has an L-shaped airflow channel inside its body, with one end connected to the central air vent on the upper surface of the seat and the other end connected to the side wall of the seat. In step S1, the gas pressure sensor (310) is installed on the side wall of the universal fixture seat (120) and is connected to the jet outlet gas path of the airbag to be tested through the L-shaped airflow channel; In step S3, the gas pressure sensor (310) directly collects the instantaneous inflation pressure data at the airbag inlet through the L-shaped airflow channel.

3. The static comprehensive test method for airbags according to claim 1, characterized in that, The specific implementation methods of step S2 include: Extract the first frame timestamp of the synchronous strobe light (230) that is captured by the first high-speed camera or the second high-speed camera and use it as the visual zero point; The rising edge of the waveform of the pulse signal sensed by the Hall current sensor (320) is extracted and used as the physical zero point; Calculate the time difference between the visual zero point and the physical zero point, and define this difference as the inherent transmission delay between the vision system and the electrical measurement system.

4. The static comprehensive test method for airbags according to claim 1, characterized in that, Step S4 further includes the step of identifying unfolding obstruction defects based on the fluid-structure response hysteresis time: If the transient pressure continues to rise during a certain period of time, but the instantaneous equivalent volume remains unchanged or increases very slowly, the duration of that period is determined. If the duration of this period significantly exceeds the preset fault judgment threshold, it is determined that the airbag has an obstruction to deployment or an internal adhesion defect. If the duration of this period does not exceed the fluid-solid response hysteresis time, it is determined to be a cold-state fabric hysteresis characteristic. The preset fault determination threshold is set based on the fluid-structure response hysteresis time multiplied by a determination tolerance coefficient.

5. The static comprehensive test method for airbags according to claim 1, characterized in that, Step S4 also includes the step of identifying leakage defects based on the adiabatic expansion theory benchmark: The initial total energy is obtained based on the amount of explosives in the gas generator. Combined with the instantaneous equivalent volume reconstructed in real time, the theoretical benchmark of adiabatic expansion under ideal conditions is deduced based on the principle of energy conservation. The measured transient pressure curve is compared with the adiabatic expansion theoretical benchmark. If the measured rate of decrease of transient pressure is faster than the theoretical benchmark of adiabatic expansion, and the instantaneous equivalent volume growth stops, then the airbag fabric is determined to be damaged or the seam is leaking.

6. The static comprehensive test method for airbags according to claim 1, characterized in that, Step S4 further includes the step of identifying material aging defects based on the pressure-volume coupling index: Preset standard airbag pressure-volume coupling index benchmark value; The calculated pressure-volume coupling index is compared with the benchmark value of the standard airbag pressure-volume coupling index. If the pressure-volume coupling index is lower than the preset material aging judgment threshold, and the transient pressure is within the normal range, then the airbag fabric material is determined to have a risk of hardening, deterioration, or elastic failure.

7. A static comprehensive testing apparatus for airbags, used to perform a static comprehensive testing method for airbags as described in any one of claims 1-6, characterized in that, include: A rigid test bench (100) provides a test reference plane, and a universal fixture seat (120) is fixed at its center. The universal fixture seat (120) has an L-shaped airflow channel inside. The dual-path imaging group (200) includes an orthogonally distributed first high-speed camera and a second high-speed camera for capturing airbag morphology; The physical quantity sensing group (300) includes a gas pressure sensor (310) mounted on the side wall of the universal fixture (120) and a Hall current sensor (320) mounted on the ignition wire. The heterogeneous data processor (400) is electrically connected to the rigid test bench (100), the dual-optical imaging group (200), and the physical quantity sensing group (300) for performing timing calibration, data acquisition, and coupling feature analysis.

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