An EBS valve body implicit defect identification method and system

Abstract

The application relates to the quality detection technical field of an electrically controlled pneumatic brake system of a commercial vehicle, and proposes an EBS valve body implicit defect identification method and system. The method comprises the following steps: obtaining stroke data and air pressure data synchronously recorded during braking of a target EBS valve body; wherein the stroke data is a stroke value sequence reflecting the displacement amount of a brake pedal or a valve core; according to the corresponding relationship between the stroke data and the air pressure data, the dynamic change rate of air pressure to stroke is calculated, and a quantitative index representing non-smooth change of air pressure is extracted based on the dynamic change rate; the quantitative index is compared with a preset defect judgment condition, and whether the target EBS valve body has an implicit defect is judged according to the comparison result. By analyzing the stroke-air pressure dynamic change rate, extracting the quantitative index and comparing the quantitative index with the preset condition, the problem that the air pressure step jump implicit defect cannot be identified only based on the macroscopic indexes such as the steady-state pressure and the response time in the prior art is solved, and accurate judgment of the implicit defect is realized.

Description

Technical Field

[0001] This application relates to the field of quality inspection technology for electronically controlled pneumatic braking systems in commercial vehicles, specifically to a method and system for identifying latent defects in EBS valve bodies. Background Technology

[0002] With the accelerated intelligentization and electrification of commercial vehicles, EBS systems have become a standard configuration in commercial vehicle braking systems. Their performance directly affects the vehicle's braking safety, driving stability, and ride comfort. The EBS valve body, as a core actuator of the braking system, includes foot valves, bridge control modules, and trailer control valves. The linearity and stability of its output pressure are crucial for ensuring smooth braking. In mass production, how to conduct comprehensive and accurate performance evaluations of EBS valve bodies during the factory bench testing phase to promptly identify various potential defects has been a long-standing technical concern in the industry. Currently, existing testing methods use pressure sensors to collect the valve body's output pressure and combine this with an industrial control computer to test items such as valve body pressure resistance, sealing performance, and response speed. For example, a single-point steady-state sampling method is used to determine pass / fail status, or pressure change curves are recorded and indicators such as maximum pressure and pressure rise time are judged; however, these methods have the following drawbacks: Due to viscous friction of the valve core, insufficient PWM drive resolution, and dead-zone nonlinearity anomalies caused by machining and assembly tolerances, EBS valve bodies may exhibit pressure step jumps during pressurization or depressurization. This type of defect does not cause obvious problems such as excessive pressure or response timeouts; it is a latent defect that cannot be identified by conventional testing, but it directly affects the braking smoothness and driving comfort of the entire vehicle. Currently, the industry lacks effective means to quantitatively identify such latent defects during bench testing, relying solely on subjective evaluation during vehicle road testing. This approach suffers from problems such as identification lag, inability to trace the defect's origin, and uncontrollable batch quality risks. Summary of the Invention

[0003] This application provides a method and system for identifying latent defects in EBS valve bodies, which can solve the technical problem that existing EBS valve body detection methods only rely on macroscopic explicit indicators such as steady-state pressure deviation and response time for qualification judgment, resulting in valve bodies that meet all macroscopic indicators still having problems such as abrupt braking and vibration, which are not smooth braking.

[0004] Firstly, this application provides a method for identifying latent defects in EBS valve bodies, comprising: Acquire the stroke data and air pressure data synchronously recorded by the target EBS valve body during braking; among which, the stroke data is a sequence of stroke values ​​reflecting the displacement of the brake pedal or valve core; Based on the correspondence between travel data and air pressure data, the dynamic rate of change of air pressure with respect to travel is calculated, and a quantitative index characterizing the non-smooth change of air pressure is extracted based on the dynamic rate of change. The quantitative indicators are compared with the preset defect judgment conditions, and the target EBS valve body is judged to have latent defects based on the comparison results.

[0005] In conjunction with the first aspect, in one approach, acquiring the stroke data and air pressure data synchronously recorded by the target EBS valve body during braking includes the following steps: Real-time acquisition of the input displacement signal and output air pressure signal of the target EBS valve body; The sampling frequency is set to a multiple higher than the frequency of dynamic air pressure changes to capture the microscopic abrupt changes in air pressure during braking, forming the original data sequence of stroke and air pressure.

[0006] In conjunction with the first aspect, one approach involves calculating the dynamic rate of change of air pressure with respect to distance travel based on the correspondence between travel data and air pressure data. This includes the following steps: Based on the original data sequence, a functional relationship curve of air pressure value changing with travel value is constructed; The first derivative of the function relationship curve is calculated using the difference algorithm to obtain the ratio of the pressure change to the stroke change between adjacent sampling points, forming a dynamic rate of change sequence. Before calculating the dynamic rate of change, the original data sequence is smoothed and filtered.

[0007] In conjunction with the first aspect, in one approach, the quantitative indicators include a maximum step amplitude indicator. This maximum step amplitude indicator, which characterizes non-smooth changes in air pressure, is extracted based on the dynamic rate of change and includes the following steps: In the dynamic rate of change sequence, abrupt changes exceeding a preset rate of change threshold are identified, and these abrupt changes are defined as potential step change points. Calculate the pressure difference within the preset travel interval before and after each potential step transition point, and use the pressure difference as the amplitude of a single step transition; By traversing the data sequence of the entire braking process, the largest amplitude value is selected from all the amplitude values ​​of single step jumps to obtain the maximum step amplitude index.

[0008] In conjunction with the first aspect, one approach also includes an effective transition point verification strategy, which comprises the following steps: After identifying potential step transition points, obtain the duration or number of consecutive sampling points corresponding to each potential step transition point; The duration or number of consecutive sampling points is compared with a preset effective feature duration threshold; only when the duration or number of consecutive sampling points is greater than the effective feature duration threshold, the potential step transition point is identified as an effective step transition point and used as the calculation range of the quantification index.

[0009] In conjunction with the first aspect, in one approach, the quantitative indicator also includes an indicator of the number of out-of-range jumps. This indicator, which characterizes non-smooth changes in air pressure, is extracted based on the dynamic rate of change and includes the following steps: Set an amplitude threshold to distinguish between normal fluctuations and defective jumps; The cumulative number of times the amplitude of a single step change exceeds the amplitude judgment threshold is counted throughout the entire braking stroke range to obtain the over-limit change count index.

[0010] In conjunction with the first aspect, one approach involves comparing quantitative indicators with preset defect judgment conditions and determining whether the EBS valve body has latent defects based on the comparison results. This includes the following steps: Set amplitude determination conditions and number determination conditions; the amplitude determination condition is that the maximum step amplitude index is greater than the preset amplitude safety threshold, and the number determination condition is that the number of jumps exceeding the standard index is greater than the preset number safety threshold. The satisfaction of the amplitude judgment condition and the number of jumps judgment condition is evaluated. Only when the maximum step amplitude index and the number of jumps exceeding the standard index simultaneously meet their respective judgment conditions is it determined that there is a latent defect in the EBS valve body.

[0011] In conjunction with the first aspect, one solution also includes a defect path tracing and localization strategy, which comprises the following steps: If a latent defect exists, the location of the fault will be determined based on the pipeline output channel that caused the stepped jump, and a fault tracing report will be generated. The location information includes foot valves, front and rear axle EPM modules, or trailer control valves.

[0012] In conjunction with the first aspect, in one scheme, the braking process includes a pressure-increasing stage from zero stroke to maximum stroke and a pressure-reducing stage from maximum stroke to zero stroke; the dynamic change rate is calculated and the presence of latent defects in the EBS valve body is determined during the pressure-increasing and pressure-reducing stages, respectively.

[0013] Secondly, embodiments of this application provide an EBS valve body latent defect identification system, which includes: The synchronous acquisition module is used to acquire the stroke data and air pressure data of the target EBS valve body synchronously recorded during the braking process; among which, the stroke data is a sequence of stroke values ​​reflecting the displacement of the brake pedal or valve core; The feature extraction module is used to calculate the dynamic change rate of air pressure with respect to the travel distance based on the correspondence between travel data and air pressure data, and to extract quantitative indicators that characterize the non-smooth changes in air pressure based on the dynamic change rate. The defect identification module is used to compare quantitative indicators with preset defect judgment conditions and determine whether the target EBS valve body has latent defects based on the comparison results.

[0014] The beneficial effects of the technical solution provided in this application include: This paper proposes a method for identifying latent defects in EBS valve bodies. Existing technologies only focus on isolated data points such as pressure extremes and response times, essentially providing a truncated static evaluation that fails to perceive the continuous changes in pressure output during braking. This application, by simultaneously acquiring stroke and air pressure data, establishes a correspondence between stroke and air pressure, expanding the detection perspective from whether the result meets standards to whether the process is smooth, thus exposing microscopic anomalies hidden in the dynamic process. Secondly, while traditional detection methods only concern themselves with the air pressure value, this method calculates the dynamic rate of change of air pressure with respect to stroke, enabling the acquisition of air pressure per unit stroke. The instantaneous and violent fluctuations in pressure are the essential characteristics of the stepped jump defect. By simultaneously collecting stroke and air pressure data and calculating its dynamic rate of change, i.e. the first derivative, the detection perspective has been successfully extended from steady state to transient state. This allows defective valve bodies that perform well in macroscopic indicators but have non-smooth changes in microscopic dynamics (such as stepped jumps and viscous friction) to be revealed. The subjective feeling of abrupt braking is transformed into a quantifiable mathematical characteristic indicator. This breaks through the blind spot of the original technical system, which could not see or accurately measure microscopic nonlinear defects. Thus, hidden defects that cause vehicle braking vibration can be accurately intercepted during the bench testing stage. Attached Figure Description

[0015] Figure 1 A schematic diagram of the core process of the EBS valve body latent defect identification method provided in this application; Figure 2 A schematic diagram of the prior art EBS valve body testing process provided for this application; Figure 3 A schematic diagram of the original characteristic curves of stroke and air pressure provided for this application; Figure 4 The defect determination logic flowchart provided for this application. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0017] To make the technical problem that this application aims to solve clearer, the causes of the technical problem will be analyzed in detail below: From the perspective of the testing system, existing EBS valve body testing technology is based on a fundamental framework of macroscopic steady-state index evaluation. This framework treats the braking process as several discrete static observation points, focusing only on a few isolated indicators such as the maximum pressure value, response time, and pressure relief lag time during braking. It determines compliance by comparing these indicators with preset thresholds. Essentially, this testing method replaces the "process" with "points" and the "behavior" with "results," losing information about the dynamic relationship between stroke and air pressure. Due to the lack of monitoring and analysis of the continuous change in air pressure during stroke, microscopic anomalies hidden in the dynamic process, such as instantaneous pressure jumps and short-term fluctuations, cannot be captured by existing testing methods, creating a detection blind spot.

[0018] From the perspective of defect characteristics, pressure gradient jumps, as a latent defect, possess unique properties distinct from traditional overt defects. First, their severity is not determined by a single factor, but rather by the combined effect of both the jump amplitude and the number of jumps. A single large jump can lead to abrupt braking, while the cumulative effect of multiple small jumps can similarly worsen braking smoothness. Second, the amplitude of gradient jumps typically does not cause overpressure or response timeouts, thus, under the current logic of judging non-compliance based on a single indicator exceeding the standard, this type of defect is considered acceptable and released. Current technology lacks a multi-dimensional joint judgment mechanism for such complex and latent defects, making it impossible to provide a scientific and quantitative evaluation.

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0020] In a first aspect, embodiments of this application provide a method for identifying latent defects in an EBS valve body, comprising: S100: Acquire the stroke data and air pressure data synchronously recorded by the target EBS valve body during braking; wherein, the stroke data is a sequence of stroke values ​​reflecting the displacement of the brake pedal or valve core; S200. Based on the correspondence between travel data and air pressure data, calculate the dynamic change rate of air pressure with respect to travel, and extract a quantitative index characterizing the non-smooth change of air pressure based on the dynamic change rate. S300: Compare the quantitative indicators with the preset defect judgment conditions, and determine whether the target EBS valve body has hidden defects based on the comparison results.

[0021] By setting up this method, we can address the shortcomings of existing technologies that focus solely on isolated data points such as pressure extremes and response times, essentially providing a truncated static evaluation that fails to perceive the continuous changes in pressure output during braking. This application, by simultaneously acquiring stroke and air pressure data and establishing a correlation between stroke and air pressure, expands the detection perspective from whether the result meets standards to whether the process is smooth, thus exposing microscopic anomalies hidden in the dynamic process. Furthermore, while traditional detection methods only concern themselves with the air pressure value, this method calculates the dynamic rate of change of air pressure with respect to stroke, enabling the acquisition of instantaneous changes in air pressure per unit stroke. Intense fluctuations are the essential characteristic of stepped jump defects. By simultaneously collecting stroke and air pressure data and calculating their dynamic rate of change, i.e., the first derivative, the detection perspective has been successfully extended from steady state to transient state. This allows defective valve bodies that perform well in macroscopic indicators but exhibit non-smooth changes in microscopic dynamics (such as stepped jumps and viscous friction) to be revealed. The subjective feeling of abrupt braking is transformed into a quantifiable mathematical characteristic indicator. This breaks through the blind spot of the original technical system, which was unable to see or accurately measure microscopic nonlinear defects. Thus, hidden defects that cause vehicle braking vibration can be accurately intercepted during the bench testing stage.

[0022] Furthermore, in one embodiment, acquiring the stroke data and air pressure data synchronously recorded by the target EBS valve body during braking includes the following steps: Real-time acquisition of the input displacement signal and output air pressure signal of the target EBS valve body; The sampling frequency is set to a multiple higher than the frequency of dynamic air pressure changes to capture the microscopic abrupt changes in air pressure during braking, forming the original data sequence of stroke and air pressure.

[0023] In this embodiment, both the input displacement signal and the output air pressure signal are acquired simultaneously, eliminating the timestamp misalignment problem caused by using different clock sources or different acquisition boards for the two types of signals in the prior art. This ensures that each set of travel data and its corresponding air pressure data correspond precisely on the time axis, avoiding misjudgment or omission of features due to timing misalignment. Furthermore, by capturing microscopic abrupt changes through a high sampling frequency, the sampling frequency is set to be a preset multiple higher than the frequency of dynamic air pressure changes, ensuring that the sampling density is sufficient to cover millisecond-level air pressure step events. During the operation of the EBS valve body, step jumps caused by valve core viscous friction or insufficient drive signal resolution typically last for tens of milliseconds. Conventional low-frequency sampling easily misses these jumps or misinterprets the air pressure value after the jump as a normal sampling point. The high sampling frequency ensures that the start time, jump amplitude, and recovery process of each jump event can be completely recorded, revealing the microscopic nonlinear characteristics hidden beneath the macroscopic smooth curve. The combination of synchronous acquisition and high-frequency sampling forms a raw data sequence that corresponds one-to-one with the travel and air pressure. This sequence completely preserves all dynamic information during the braking process, including the smooth rise of air pressure, possible step-like jumps, and the recovery behavior after the jumps.

[0024] Furthermore, in one embodiment, the dynamic rate of change of air pressure with respect to travel distance is calculated based on the correspondence between travel data and air pressure data, which includes the following steps: Based on the original data sequence, a functional relationship curve of air pressure value changing with travel value is constructed; The first derivative of the function relationship curve is calculated using the difference algorithm to obtain the ratio of the pressure change to the stroke change between adjacent sampling points, forming a dynamic rate of change sequence. Before calculating the dynamic rate of change, the original data sequence is smoothed and filtered.

[0025] In this embodiment, by constructing a pressure-stroke function relationship curve and using a differential algorithm to calculate the first derivative, the discrete raw data is transformed into a dynamic rate of change sequence that accurately reflects the rate of change of pressure. This significantly amplifies and quantifies the microscopic step-like jump features hidden in the braking process from the imperceptible background. At the same time, the raw data sequence is smoothed and filtered before calculating the derivative, effectively eliminating high-frequency interference introduced by sensor electrical noise and mechanical vibration, avoiding the amplification effect of differential operation on noise, and ensuring that subsequent feature extraction can accurately distinguish between real mechanical defect jumps and false noise fluctuations, thereby improving the accuracy and anti-interference capability of hidden defect identification.

[0026] Furthermore, in one embodiment, the quantification index includes a maximum step amplitude index. The maximum step amplitude index, which characterizes non-smooth changes in air pressure, is extracted based on the dynamic rate of change and includes the following steps: In the dynamic rate of change sequence, abrupt changes exceeding a preset rate of change threshold are identified, and these abrupt changes are defined as potential step change points. Calculate the pressure difference within the preset travel interval before and after each potential step transition point, and use the pressure difference as the amplitude of a single step transition; By traversing the data sequence of the entire braking process, the largest amplitude value is selected from all the amplitude values ​​of single step jumps to obtain the maximum step amplitude index.

[0027] In this embodiment, potential step jump points are identified in the dynamic rate of change sequence by setting a rate of change threshold. This effectively filters out the slow changes in air pressure and the small fluctuations caused by random noise during normal smooth braking, ensuring that only instantaneous air pressure step events that truly reflect valve core viscous friction or insufficient drive signal resolution are included in the analysis. Based on this, the air pressure difference within a preset stroke interval before and after each potential jump point is calculated as the single jump amplitude, avoiding amplitude misjudgment caused by abnormal fluctuations at a single sampling point, making the amplitude calculation more stable and reliable. Finally, the maximum value is selected from all single jump amplitudes as the maximum step amplitude index. This index directly reflects the degree of the most severe air pressure impact on the valve body during the entire braking process, providing a key quantitative basis for measuring the risk of abrupt braking for subsequent judgment, and allowing the severity of hidden defects to be scientifically measured.

[0028] Furthermore, in one embodiment, an effective transition point verification strategy is also included, which comprises the following steps: After identifying potential step transition points, obtain the duration or number of consecutive sampling points corresponding to each potential step transition point; The duration or number of consecutive sampling points is compared with a preset effective feature duration threshold; only when the duration or number of consecutive sampling points is greater than the effective feature duration threshold, the potential step transition point is identified as an effective step transition point and used as the calculation range of the quantification index.

[0029] In this embodiment, after identifying potential step transition points, an effective transition point verification strategy is introduced. By comparing the duration or number of consecutive sampling points with a preset threshold, each potential transition point is screened a second time. Transient interference events that have a change rate exceeding the threshold but a very short duration are excluded. This ensures that only real mechanical defect transitions with a certain duration can be identified as effective step transition points and included in the calculation of subsequent quantitative indicators. This verification strategy effectively distinguishes between continuous air pressure steps caused by valve core sticky friction or machining and assembly tolerances and instantaneous spike interference caused by electrical noise or external vibrations. It avoids misjudging accidental noise fluctuations as structural defects, reduces the false detection rate and the missed detection rate, and makes the identification results of hidden defects closer to the real physical state of the valve body.

[0030] Furthermore, in one embodiment, the quantitative indicator also includes an index of the number of out-of-range jumps, which is extracted based on the dynamic rate of change to characterize the non-smooth changes in air pressure. This includes the following steps: Set an amplitude threshold to distinguish between normal fluctuations and defective jumps; The cumulative number of times the amplitude of a single step change exceeds the amplitude judgment threshold is counted throughout the entire braking stroke range to obtain the over-limit change count index.

[0031] In this embodiment, by introducing an over-limit jump frequency index to complement the maximum step amplitude index, a quantitative evaluation system with two dimensions—amplitude and frequency—is constructed. This index sets an amplitude judgment threshold and counts the cumulative number of times a single jump amplitude exceeds this threshold throughout the entire braking stroke. This effectively reflects the frequency of step jumps occurring in the valve body during braking. In practical applications, even if a single jump amplitude does not reach an extreme level, repeated jumps can still severely degrade braking smoothness, causing the driver to experience a continuous jerkiness. Conversely, if there is only one large jump but the number of jumps is very small, it may only be an occasional anomaly. The existence of the over-limit jump frequency index allows the judgment logic to simultaneously consider the severity and frequency of jumps, avoiding potential omissions or misjudgments caused by a single amplitude index. This provides a comprehensive and scientific quantitative basis for subsequent dual-threshold joint judgment, ensuring that the identification results of hidden defects are more consistent with the actual working performance of the valve body.

[0032] Furthermore, in one embodiment, the quantitative indicators are compared with preset defect judgment conditions, and the presence of latent defects in the EBS valve body is determined based on the comparison results. This includes the following steps: Set amplitude determination conditions and number determination conditions; the amplitude determination condition is that the maximum step amplitude index is greater than the preset amplitude safety threshold, and the number determination condition is that the number of jumps exceeding the standard index is greater than the preset number safety threshold. The satisfaction of the amplitude judgment condition and the number of jumps judgment condition is evaluated. Only when the maximum step amplitude index and the number of jumps exceeding the standard index simultaneously meet their respective judgment conditions is it determined that there is a latent defect in the EBS valve body.

[0033] In this embodiment, by setting amplitude and frequency judgment conditions and using "AND logic" for evaluation, a latent defect in the valve body is determined only when the maximum step amplitude index exceeds the amplitude safety threshold and the number of excessive jumps simultaneously exceeds the frequency safety threshold. This judgment mechanism effectively overcomes the limitations of single-dimensional judgment. In actual braking, a single large jump may be an occasional abnormal fluctuation, while the accumulation of multiple small jumps may not yet reach the level affecting braking smoothness. Only when both amplitude and frequency conditions are met simultaneously can a substantial structural defect in the valve body be confirmed. This dual-dimensional joint judgment method avoids false detections caused by single accidental fluctuations and prevents missed detections due to small but frequent jump amplitudes. This makes the judgment results more closely reflect the actual performance of the valve body in actual vehicle operation, improving the accuracy of latent defect identification.

[0034] Furthermore, in one embodiment, a defect channel tracing and localization strategy is also included, which comprises the following steps: If a latent defect exists, the location of the fault will be determined based on the pipeline output channel that caused the stepped jump, and a fault tracing report will be generated. The location information includes foot valves, front and rear axle EPM modules, or trailer control valves.

[0035] In this embodiment, a defect tracing and localization strategy is introduced after a latent defect is determined. Based on the pipeline output channel that causes a stepped change, the specific location of the fault is automatically located, and a fault tracing report containing information such as foot valves, front and rear axle EPM modules, or trailer control valves is generated. This upgrades the detection result from a simple "pass or fail" to precise location information including the defect location. This solves the pain point in existing technologies where even if braking smoothness issues are detected, the type of faulty valve body cannot be quickly determined. The specific valve body channel with the defect can be accurately located during the bench testing stage, avoiding the high time and labor costs of disassembling and inspecting each vehicle after assembly. This shortens the fault localization cycle, provides a clear direction for rapid response and process improvement on the production line, and also provides traceable data support for defect tracing and quality responsibility determination during after-sales repair.

[0036] Furthermore, in one embodiment, the braking process includes a pressure-increasing phase from zero stroke to maximum stroke and a pressure-reducing phase from maximum stroke to zero stroke; the dynamic change rate is calculated and the presence of latent defects in the EBS valve body is determined during the pressure-increasing and pressure-reducing phases, respectively.

[0037] In this embodiment, by clearly dividing the braking process into a pressure boost stage from zero stroke to maximum stroke and a pressure reduction stage from maximum stroke to zero stroke, and calculating the dynamic change rate separately in these two stages and independently performing implicit defect determination, the detection range covers the complete cycle of the valve body operation. In practical applications, the step jumps caused by spool viscous friction or insufficient drive signal resolution are not limited to the pressure boost process. When the spool returns during the pressure reduction stage, pressure steps may also occur due to uneven lubrication or abnormal spring force. Even in some valve bodies, the jumps in the pressure reduction stage are more significant. If only the pressure boost stage is detected, the implicit defects that only appear in the pressure reduction stage may be missed, resulting in misjudging the defective valve body as a qualified product. The phased independent detection strategy ensures that no matter which stage of the braking process the defect appears in, it can be effectively captured. At the same time, the individual determination results of the pressure boost and pressure reduction stages can also confirm each other, providing more comprehensive data support for the comprehensive performance evaluation of the valve body and further improving the reliability of the detection.

[0038] In a second aspect, the embodiment of the present application further provides an EBS valve body implicit defect identification system, which includes: A synchronous acquisition module, which is used to obtain the stroke data and air pressure data synchronously recorded during the braking process of the target EBS valve body; wherein, the stroke data is a sequence of stroke values reflecting the displacement of the brake pedal or the spool. A feature extraction module, which is used to calculate the dynamic change rate of air pressure with respect to stroke according to the correspondence between the stroke data and the air pressure data, and extract a quantization index characterizing the non-smooth change of air pressure based on the dynamic change rate. A defect identification module, which is used to compare the quantization index with the preset defect determination condition, and determine whether there is an implicit defect in the target EBS valve body according to the comparison result.

[0039] By setting such a system, specifically as follows: The synchronous acquisition module includes a high-precision stroke sensor, a high-frequency air pressure sensor, and a synchronous acquisition unit. The high-precision stroke sensor is installed at the pedal actuator or the spool drive end for real-time acquisition of displacement signals; the high-frequency air pressure sensor is arranged on the pipeline of each output channel of the valve body for real-time acquisition of the air pressure signals of each channel; the synchronous acquisition unit provides a unified clock reference for the stroke sensor and the air pressure sensor, synchronously acquires the two types of signals at the same sampling frequency, and marks corresponding timestamps for each set of stroke data and air pressure data to ensure their precise alignment on the time axis. The feature extraction module incorporates a first-order differential derivative calculation algorithm. After smoothing and filtering the synchronously acquired raw data sequence, it calculates the ratio of pressure change to stroke change between adjacent sampling points, forming a dynamic rate of change sequence. Then, it identifies potential step transition points exceeding a preset rate of change threshold in the dynamic rate of change sequence and filters out valid transition points through verification strategies based on duration or number of consecutive sampling points. Finally, it calculates the single transition amplitude corresponding to each valid transition point and extracts the maximum step amplitude index and the number of over-limit transitions index from all single transition amplitudes.

[0040] The defect identification module has preset amplitude safety thresholds and frequency safety thresholds. It uses "AND logic" of amplitude judgment conditions and frequency judgment conditions for joint evaluation. Only when the maximum step amplitude index exceeds the amplitude safety threshold and the number of jumps exceeds the frequency safety threshold at the same time, it is determined that the target EBS valve body has a hidden defect.

[0041] As a preferred option, the system also includes a pedal actuator and a device base. The device base is equipped with standardized installation stations for clamping and fixing various EBS valve bodies such as foot valves, front and rear axle EPM modules, and trailer control valves. The pedal actuator is equipped with a servo drive component to drive the brake pedal or valve core at a constant drive rate to complete the full braking action from zero stroke to maximum stroke, as well as the reset action from maximum stroke back to zero stroke, providing a stable stroke input for the synchronous acquisition module.

[0042] As another preferred option, the system also includes a defect location module, which is connected to the defect identification module. When a latent defect is determined to exist, it is used to automatically locate the valve body type and channel location where the fault occurs based on the pipeline output channel that causes the step change, and generate a fault tracing report containing information such as foot valves, front and rear axle EPM modules, or trailer control valves.

[0043] As another preferred solution, the system also includes a data display and storage module, which is used to display the stroke-pressure characteristic curve, dynamic change rate curve, quantitative index calculation results and defect judgment conclusions in real time, and store the detection data and judgment results in the local database or upload them to the production line MES system to achieve traceable management of detection data.

[0044] The functions of each module in the aforementioned EBS valve body latent defect identification system correspond to the steps in the aforementioned EBS valve body latent defect identification method embodiment, and their functions and implementation processes will not be described in detail here.

[0045] like Figure 3As shown, the stroke-pressure characteristic curve of the trailer control valve exhibits numerous obvious stepped jumps during both the pressurization and depressurization phases. During pressurization, the pressure does not rise smoothly with increasing stroke, but rather shows instantaneous jumps at multiple stroke positions, with positive jump amplitudes ranging from 34 kPa to 90 kPa. Similarly, during depressurization, multiple reverse jumps occur, with amplitudes ranging from 33 kPa to 85 kPa. The entire pressure curve shows a clear non-smooth characteristic, indicating a serious hidden structural defect in the valve body. Road testing with the valve body assembled on a vehicle revealed noticeable abruptness and jerking during braking, indicating substandard smoothness. The test results were highly consistent with the actual vehicle performance.

[0046] The stroke-pressure characteristic curve of the front axle control EPM module exhibits good linearity and smoothness across the entire stroke range. During the complete braking process from zero stroke to maximum stroke, the pressure difference between adjacent data acquisition nodes is less than 5 kPa. No effective step transition points satisfying the derivative and duration thresholds were identified, the maximum step amplitude is less than 5 kPa, and the number of excessive transitions is zero. Road testing with the valve body assembled in a vehicle verified that the braking feel is smooth, the pressure output is linear, and there is no adverse feedback on smoothness, meeting the vehicle design requirements.

[0047] The stroke-pressure characteristic curve of the rear axle control EPM module has better overall smoothness than that of the trailer control valve. However, there are three significant step jumps during the pressurization phase, with the jump amplitude ranging from 62kPa to 65kPa. During the depressurization phase, there is a reverse jump with an amplitude of 80.16kPa. Although the jump amplitude exceeds the acceptable threshold, the number of jumps does not exceed the acceptable threshold. According to the dual-threshold joint judgment rule of this invention, the valve body is still judged as qualified. Road tests were conducted on the assembled vehicle, and the vehicle braking was linear and smooth, without any jerking or abruptness. The braking smoothness meets the vehicle design requirements.

[0048] The test results of the above three types of valve bodies show that the hidden defect identification method based on the step characteristics of the air pressure characteristic curve proposed in this invention can effectively distinguish different degrees of air pressure non-smooth changes, and make scientific judgments based on the dual-dimensional quantitative indicators of amplitude and frequency. The test results are highly consistent with the subjective evaluation of the braking smoothness of the actual vehicle.

[0049] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0050] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0051] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0052] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0053] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0054] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0055] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for identifying latent defects in EBS valve bodies, characterized in that, It includes: Acquire the stroke data and air pressure data synchronously recorded by the target EBS valve body during braking; wherein, the stroke data is a sequence of stroke values ​​reflecting the displacement of the brake pedal or valve core; Based on the correspondence between the travel data and the air pressure data, the dynamic change rate of air pressure with respect to travel is calculated, and a quantitative index characterizing the non-smooth change of air pressure is extracted based on the dynamic change rate. The quantitative indicators are compared with preset defect judgment conditions, and the target EBS valve body is judged to have latent defects based on the comparison results.

2. The method for identifying latent defects in EBS valve bodies as described in claim 1, characterized in that, Acquiring the stroke data and air pressure data synchronously recorded by the target EBS valve body during braking includes the following steps: The input displacement signal and output air pressure signal of the target EBS valve body are acquired in real time. The sampling frequency is set to a multiple higher than the frequency of dynamic air pressure changes to capture the microscopic abrupt changes in air pressure during braking, forming the original data sequence of stroke and air pressure.

3. The method for identifying latent defects in EBS valve bodies as described in claim 2, characterized in that, Based on the correspondence between the travel data and the air pressure data, the dynamic rate of change of air pressure with respect to travel is calculated, which includes the following steps: Based on the original data sequence, a functional relationship curve of air pressure value changing with travel value is constructed; The first derivative of the function relationship curve is calculated using a difference algorithm to obtain the ratio of the pressure change to the stroke change between adjacent sampling points, forming a dynamic rate of change sequence. Before calculating the dynamic rate of change, the original data sequence is subjected to a smoothing filter.

4. The method for identifying latent defects in EBS valve bodies as described in claim 3, characterized in that, The quantitative indicators include the maximum step amplitude indicator. The maximum step amplitude indicator, which characterizes the non-smooth change in air pressure, is extracted based on the dynamic rate of change. This extraction process includes the following steps: In the dynamic rate of change sequence, abrupt changes exceeding a preset rate of change threshold are identified, and these abrupt changes are defined as potential step change points. Calculate the air pressure difference within a preset travel interval before and after each potential step jump point, and use the air pressure difference as the amplitude of a single step jump; By traversing the data sequence of the entire braking process, the largest amplitude value is selected from all the amplitude values ​​of single step jumps to obtain the maximum step amplitude index.

5. The method for identifying latent defects in EBS valve bodies as described in claim 4, characterized in that, It also includes an effective transition point verification strategy, which includes the following steps: After identifying the potential step transition points, obtain the duration or number of consecutive sampling points corresponding to each potential step transition point; The duration or number of consecutive sampling points is compared with a preset effective feature duration threshold; only when the duration or number of consecutive sampling points is greater than the effective feature duration threshold, the potential step transition point is confirmed as an effective step transition point and used as the calculation range of the quantification index.

6. The method for identifying latent defects in EBS valve bodies as described in claim 4, characterized in that, The quantitative indicators also include an index of the number of out-of-range jumps. This index, which characterizes the non-smooth changes in air pressure, is extracted based on the dynamic change rate and includes the following steps: Set an amplitude threshold to distinguish between normal fluctuations and defective jumps; The number of times the amplitude of a single step change exceeds the amplitude judgment threshold is counted throughout the entire braking stroke range to obtain the over-limit change count index.

7. The method for identifying latent defects in EBS valve bodies as described in claim 6, characterized in that, The quantitative indicators are compared with preset defect judgment conditions, and the presence of latent defects in the EBS valve body is determined based on the comparison results. This includes the following steps: Set amplitude determination conditions and number determination conditions; the amplitude determination condition is that the maximum step amplitude index is greater than the preset amplitude safety threshold, and the number determination condition is that the number of over-limit jumps is greater than the preset number safety threshold. The satisfaction of the amplitude determination condition and the number determination condition is evaluated. Only when the maximum step amplitude index and the number of overshooting jump index simultaneously meet their respective determination conditions is it determined that the EBS valve body has a latent defect.

8. The method for identifying latent defects in EBS valve bodies as described in claim 6, characterized in that, It also includes a defect tracing and localization strategy, which includes the following steps: If a latent defect exists, the location of the fault is determined based on the pipeline output channel that caused the stepped jump, and a fault tracing report is generated; wherein, the location information includes foot valves, front and rear axle EPM modules, or trailer control valves.

9. The method for identifying latent defects in EBS valve bodies as described in claim 1, characterized in that, The braking process includes a pressure increase phase from zero stroke to maximum stroke and a pressure decrease phase from maximum stroke to zero stroke; the dynamic change rate is calculated during the pressure increase phase and the pressure decrease phase, respectively, and it is determined whether the EBS valve body has any latent defects.

10. A latent defect identification system for EBS valve bodies, characterized in that, It includes: The synchronous acquisition module is used to acquire the stroke data and air pressure data synchronously recorded by the target EBS valve body during braking; wherein, the stroke data is a sequence of stroke values ​​reflecting the displacement of the brake pedal or valve core; The feature extraction module is used to calculate the dynamic change rate of air pressure with respect to the travel distance based on the correspondence between the travel data and the air pressure data, and to extract a quantitative index characterizing the non-smooth change of air pressure based on the dynamic change rate. The defect identification module is used to compare the quantitative indicators with preset defect judgment conditions, and determine whether the target EBS valve body has a latent defect based on the comparison result.

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