Abnormality recognition method and system for drum brake system based on air pressure and deceleration

Abstract

The application discloses a kind of drum brake system abnormality identification method and system based on air pressure and deceleration, belong to vehicle braking system fault diagnosis technical field, solve the problem that existing technology cannot effectively distinguish air pressure establishment anomaly and mechanical brake execution end anomaly.This method includes: obtaining the air pressure signal and vehicle dynamic response signal of braking system in braking process;According to air pressure signal, determine the pressure build time, and according to vehicle dynamic response signal, determine the deceleration build time;Based on the time difference between pressure build time and deceleration build time, determine additional response delay;When air pressure establishment feature meets preset normal condition, and additional response delay increases relative to preset reference response delay and / or vehicle deceleration response feature is degraded relative to preset reference response, it is determined that mechanical brake execution end anomaly exists in braking system.The method can identify the abnormal state of mechanical execution link under the condition that brake air pressure is normally established.

Description

Technical Field

[0001] This invention belongs to the field of vehicle braking system fault diagnosis technology, specifically relating to a method for identifying anomalies in a drum braking system based on air pressure and deceleration. Background Technology

[0002] In the prior art, the braking response of a pneumatic drum brake system typically involves the following series of steps: the brake controller outputs a braking command, the electronically controlled brake valve or relay valve actuates, compressed air enters the brake line and brake chamber, the brake chamber outputs mechanical displacement, the brake transmission mechanism drives the brake pads to move, the brake pads cross the gap between themselves and the brake drum, the brake pads contact the brake drum and establish effective friction, the wheel generates braking torque, and finally the entire vehicle generates a measurable deceleration.

[0003] In brake system fault diagnosis, simply relying on whether the vehicle's deceleration decreases is insufficient to accurately pinpoint the specific response stage of the abnormality. On one hand, problems in the air pressure build-up stage, such as insufficient air supply pressure, abnormal valve response, or air circuit leaks, can all lead to decreased deceleration, just as problems in the mechanical actuator stage, such as abnormal mechanical transmission, increased brake shoe-drum clearance, or decreased friction performance, cannot be effectively distinguished based solely on deceleration detection. On the other hand, even if the abnormality is determined to occur in the mechanical actuator stage, the response characteristics caused by changes in the clearance between the brake shoes and brake drum can easily be confused with other mechanical transmission abnormalities, making it difficult to further identify the specific fault type of abnormal brake shoe-drum clearance from the mechanical actuator stage. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0005] One objective of this invention is to solve the problem that existing technologies cannot effectively distinguish between abnormalities in the air pressure build-up process and abnormalities in the mechanical braking actuator.

[0006] One object of the present invention is to provide a method for anomaly identification of a drum braking system based on air pressure and deceleration, comprising:

[0007] Acquire air pressure signals and vehicle dynamic response signals of the braking system during the braking process;

[0008] The pressure establishment time is determined based on the air pressure signal, and the deceleration establishment time is determined based on the vehicle dynamic response signal. The pressure establishment time is the moment when the air pressure reaches a preset effective pressure condition, and the deceleration establishment time is the moment when the vehicle deceleration reaches a preset effective deceleration condition.

[0009] The additional response delay is determined based on the time difference between the pressure establishment time and the deceleration establishment time;

[0010] Obtain air pressure build-up characteristics that characterize the air pressure build-up process, and obtain vehicle deceleration response characteristics that characterize the deceleration response process;

[0011] When the air pressure build-up characteristic meets the preset normal conditions, and the additional response delay increases relative to the preset reference response delay and / or the vehicle deceleration response characteristic degrades relative to the preset reference response, it is determined that there is an abnormality in the mechanical braking execution end of the braking system.

[0012] Preferably, in the method for anomaly identification of a drum braking system based on air pressure and deceleration, the air pressure establishment feature includes air pressure establishment delay and air pressure amplitude, wherein the air pressure establishment delay is the time difference between the air pressure establishment time and the braking control command time.

[0013] The pressure establishment feature meets preset normal conditions, including: the pressure establishment delay does not exceed a preset pressure delay threshold, and the pressure amplitude meets preset effective pressure conditions.

[0014] Preferably, in the method for identifying anomalies in a drum braking system based on air pressure and deceleration, when the air pressure build-up delay exceeds a preset air pressure delay threshold and / or the air pressure amplitude does not meet the preset effective pressure condition, it is determined that the air pressure build-up characteristic does not meet the preset normal condition, and it is determined that there is an air pressure build-up anomaly in the braking system.

[0015] Preferably, in the method for identifying anomalies in a drum braking system based on air pressure and deceleration, when the additional response delay increases relative to a preset reference response delay and / or the vehicle deceleration response characteristics degrade relative to a preset reference response, it is determined that there is an anomaly in the mechanical braking actuator of the braking system, including:

[0016] When the additional response delay exceeds the preset baseline response delay and / or the vehicle deceleration response characteristic is lower than the preset baseline response, it is determined that there is an abnormality in the mechanical braking execution end of the braking system.

[0017] Preferably, in the method for identifying anomalies in a drum braking system based on air pressure and deceleration, when the additional response delay increases relative to a preset reference response delay and / or the vehicle deceleration response characteristics degrade relative to a preset reference response, it is determined that there is an anomaly in the mechanical braking actuator of the braking system, including:

[0018] The additional delay response degradation parameter is determined based on the additional response delay;

[0019] Determine the vehicle deceleration response characteristic degradation parameters based on the vehicle deceleration response characteristics;

[0020] Weights are assigned to the additional delay response degradation parameter and the vehicle deceleration response characteristic degradation parameter, respectively. The additional delay response degradation parameter and the vehicle deceleration response characteristic degradation parameter are then weighted and summed to determine the mechanical anomaly evaluation parameters.

[0021] When the mechanical anomaly evaluation parameters exceed the preset mechanical anomaly threshold, it is determined that there is an anomaly in the mechanical braking execution end of the braking system.

[0022] Preferably, in the method for anomaly identification of a drum braking system based on air pressure and deceleration, the step of determining the additional delay response degradation parameter based on the additional response delay includes:

[0023] The additional delay response degradation parameter is determined based on the relative deviation of the additional response delay from the preset baseline additional response delay.

[0024] Preferably, in the method for anomaly identification of a drum braking system based on air pressure and deceleration, the step of determining the vehicle deceleration response characteristic degradation parameter based on the vehicle deceleration response characteristics includes:

[0025] The degradation parameter of the vehicle deceleration response characteristic is determined based on the relative deviation of the vehicle deceleration response characteristic relative to the preset reference response.

[0026] Preferably, in the method for identifying anomalies in a drum braking system based on air pressure and deceleration, when the additional response delay increases relative to a preset reference response delay and the vehicle deceleration response characteristics degrade relative to a preset reference response, it is determined that there is an anomaly in the mechanical braking actuator of the braking system, including:

[0027] Acquire multiple additional response delays and / or multiple vehicle deceleration response characteristics corresponding to multiple detection cycles;

[0028] When the plurality of additional response delays exceed the preset baseline response delay starting from the first detection period, and show a continuous increasing trend in multiple consecutive detection periods after the first detection period, and / or

[0029] When the deceleration response characteristics of the multiple vehicles fall below the preset benchmark response starting from the second detection cycle, and show a continuous degradation trend in multiple consecutive detection cycles after the second detection cycle,

[0030] The braking system was found to have mechanical degradation related to abnormal clearance between the brake shoes and brake drum.

[0031] Preferably, in the method for identifying anomalies in a drum braking system based on air pressure and deceleration, the vehicle deceleration response characteristics include actual deceleration and / or pressure-deceleration response gain; wherein, the pressure-deceleration response gain is determined based on the ratio between actual deceleration and braking pressure.

[0032] Another object of the present invention is to provide an anomaly detection system for a drum braking system based on air pressure and deceleration, comprising:

[0033] The acquisition module is used to acquire the air pressure signal and vehicle dynamic response signal of the braking system during the braking process;

[0034] The determination module determines the pressure establishment time based on the air pressure signal and the deceleration establishment time based on the vehicle dynamic response signal, wherein the pressure establishment time is the moment when the air pressure reaches a preset effective pressure condition, and the deceleration establishment time is the moment when the vehicle deceleration reaches a preset effective deceleration condition.

[0035] The calculation module is used to determine the additional response delay based on the time difference between the pressure establishment time and the deceleration establishment time;

[0036] The extraction module is used to obtain air pressure build-up features characterizing the air pressure build-up process and vehicle deceleration response features characterizing the deceleration response process.

[0037] The determination module is used to determine that there is an abnormality in the mechanical braking actuator of the braking system when the air pressure establishment feature meets the preset normal conditions, and the additional response delay increases relative to the preset reference response delay and / or the vehicle deceleration response feature degrades relative to the preset reference response.

[0038] The present invention has at least the following beneficial effects:

[0039] This invention determines the pressure build-up time and deceleration build-up time by acquiring air pressure signals and vehicle dynamic response signals during braking, and uses the time difference between the two as an additional response delay. During the determination, it first checks whether the air pressure build-up characteristics meet preset normal conditions. When the air pressure build-up characteristics are normal, it then checks whether the additional response delay exceeds a preset baseline response delay, and whether the vehicle deceleration response characteristics are lower than a preset baseline response. If the additional response delay exceeds the baseline value, it indicates that the mechanical action time from air pressure build-up to deceleration has increased; if the deceleration response characteristics are lower than the baseline value, it indicates that the response capability of the mechanical actuator has decreased. This method performs mechanical end determination under the premise that the air pressure build-up characteristics are normal, which can distinguish between mechanical actuator abnormalities and air pressure build-up abnormalities, solving the problem that relying solely on deceleration detection cannot locate the fault.

[0040] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the pneumatic drum brake response chain in Embodiment 2 of the present invention.

[0042] Figure 2 This is a timing diagram showing the braking command, pressure, and deceleration relationship in Embodiment 2 of the present invention.

[0043] Figure 3 For example, t in Embodiment 2 of the present invention cmd t P and t A Definition diagram.

[0044] Figure 4 Δt in Embodiment 2 of the present invention m Calculation diagram.

[0045] Figure 5 This is a timing diagram of the normal state in Embodiment 2 of the present invention.

[0046] Figure 6 This is a timing diagram of the abnormal air pressure establishment in Embodiment 2 of the present invention.

[0047] Figure 7 This is a timing diagram of an abnormality at the mechanical execution end in Embodiment 2 of the present invention.

[0048] Figure 8 This is a flowchart of the abnormal layered diagnosis process in Embodiment 2 of the present invention.

[0049] Figure 9 This is a graph showing the pressure-deceleration gain variation in Embodiment 2 of the present invention.

[0050] Figure 10 Δt in Embodiment 2 of the present invention m Historical degradation trend chart.

[0051] Figure 11 This is a block diagram of the abnormal hierarchical diagnosis system according to Embodiment 2 of the present invention.

[0052] Figure 12 This is a network architecture diagram of the anomaly hierarchical diagnosis system in Embodiment 2 of the present invention. Detailed Implementation

[0053] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0054] like Figures 1 to 12As shown, this invention provides a method for anomaly identification of a drum braking system based on air pressure and deceleration, comprising: acquiring air pressure signals and vehicle dynamic response signals of the braking system during the braking process; determining the pressure establishment time based on the air pressure signals and the deceleration establishment time based on the vehicle dynamic response signals, wherein the pressure establishment time is the time when the air pressure reaches a preset effective pressure condition, and the deceleration establishment time is the time when the vehicle deceleration reaches a preset effective deceleration condition; determining an additional response delay based on the time difference between the pressure establishment time and the deceleration establishment time; acquiring air pressure establishment characteristics characterizing the air pressure establishment process and acquiring vehicle deceleration response characteristics characterizing the deceleration response process; determining that there is an anomaly in the mechanical braking execution end of the braking system when the air pressure establishment characteristics meet preset normal conditions, and the additional response delay increases relative to a preset reference response delay and / or the vehicle deceleration response characteristics degrade relative to a preset reference response.

[0055] During implementation, the first step is to acquire the air pressure signal and vehicle dynamic response signal of the braking system during braking. The air pressure signal can be collected by a pressure sensor installed in the brake line, relay valve output, or brake chamber. The vehicle dynamic response signal can be acquired by a vehicle speed sensor, wheel speed sensor, inertial measurement unit, or vehicle positioning system. Both signals need to be synchronized after acquisition, which can be achieved using a unified controller timestamp, CAN message timestamp correction, or global navigation satellite system time synchronization.

[0056] Next, the pressure establishment time is determined based on the collected air pressure signal. The pressure establishment time refers to the moment when the air pressure reaches a preset effective pressure condition. The preset effective pressure condition can be set as the air pressure value reaching a preset absolute pressure threshold, such as the brake chamber pressure reaching 40 kPa; it can also be set as the air pressure value reaching a preset percentage of the target pressure, such as reaching 80% of the target braking pressure; or it can be set as the air pressure change rate exceeding a preset threshold or the air pressure entering a preset stable pressure range. In specific implementation, when the air pressure signal value first reaches the preset effective pressure threshold and remains there for a certain period of time, this starting moment is determined as the pressure establishment time.

[0057] Simultaneously, the deceleration establishment time is determined based on the vehicle's dynamic response signal. The deceleration establishment time refers to the moment when the vehicle's deceleration reaches the preset effective deceleration condition. To eliminate signal noise interference, the vehicle's dynamic response signal can first be processed by low-pass filtering, moving average, or Kalman filtering. The preset effective deceleration condition can be set as the absolute value of the vehicle's longitudinal deceleration reaching a preset deceleration threshold, such as 1.47 m / s²; it can also be set as the preset proportion of the vehicle's longitudinal deceleration reaching the target deceleration; or it can be set as the vehicle's speed reduction rate reaching a preset threshold or the filtered deceleration continuously meeting the preset condition for a preset time. In specific implementation, when the absolute value of the filtered deceleration signal first reaches the preset deceleration threshold and remains there for a certain period of time, this starting moment is determined as the deceleration establishment time.

[0058] Then, based on the time difference between the pressure establishment time and the deceleration establishment time, the additional response delay is determined. This time difference corresponds to the mechanical execution process from the effective establishment of brake air pressure to the generation of effective deceleration of the vehicle, including the movement of the brake chamber push rod, the brake shoes crossing the gap between the brake drum, and the contact between the brake shoes and the brake drum to establish effective friction.

[0059] Simultaneously, air pressure build-up characteristics, characterizing the air pressure build-up process, and vehicle deceleration response characteristics, characterizing the deceleration response process, are acquired. Air pressure build-up characteristics reflect the response performance of the air pressure from the issuance of the braking command to its effective build-up. Vehicle deceleration response characteristics reflect the vehicle's deceleration response performance after the braking air pressure has been built up.

[0060] After acquiring the above features, the process proceeds to the anomaly detection stage. First, it checks whether the air pressure establishment feature meets the preset normal conditions. If the air pressure establishment feature does not meet the preset normal conditions, it indicates an anomaly occurred during the air pressure establishment process, and the process does not proceed to the mechanical actuator anomaly detection path. If the air pressure establishment feature meets the preset normal conditions, it indicates that the air pressure establishment process is normal, and the process then proceeds to the mechanical actuator anomaly detection.

[0061] Under the premise that the air pressure build-up characteristics meet the preset normal conditions, the additional response delay is compared with the preset baseline response delay, and the vehicle deceleration response characteristics are compared with the preset baseline response. The preset baseline response delay and preset baseline response can be determined based on the calibration data of healthy vehicles of the same model, the target vehicle's factory health status data, or the target vehicle's post-maintenance health status data. When the additional response delay increases relative to the preset baseline response delay, it indicates that the mechanical action time between effective air pressure build-up and effective deceleration has increased; when the vehicle deceleration response characteristics degrade relative to the preset baseline response, it indicates that the responsiveness of the mechanical actuation link has decreased. If either or both of the above conditions are met, it is determined that there is an abnormality in the mechanical braking actuation end of the braking system.

[0062] This implementation method, assuming normal air pressure build-up characteristics, uses the time difference between the pressure build-up moment and the deceleration build-up moment, along with the deceleration response characteristics, as the judgment criteria. When the air pressure is normal but the time difference increases, it indicates an increase in the time consumed by the mechanical execution process; when the air pressure is normal but the deceleration response characteristics degrade, it indicates a decrease in the responsiveness of the mechanical execution component. This allows the fault to be located at the mechanical braking actuator, solving the problem in existing technologies where it is impossible to distinguish between abnormal air pressure build-up and abnormal mechanical execution.

[0063] In a preferred embodiment, in the method for anomaly identification of a drum braking system based on air pressure and deceleration, the air pressure establishment feature includes air pressure establishment delay and air pressure amplitude. The air pressure establishment delay is the time difference between the air pressure establishment time and the braking control command time. The air pressure establishment feature meets preset normal conditions, including: the air pressure establishment delay does not exceed a preset air pressure delay threshold, and the air pressure amplitude meets a preset effective pressure condition.

[0064] In a specific embodiment of the present invention, the air pressure establishment characteristic includes two parameters: air pressure establishment delay and air pressure amplitude. Air pressure establishment delay refers to the time difference between the pressure establishment moment and the braking control command moment, used to measure the length of time from when the brake controller issues a braking command to when the air pressure reaches an effective level. Air pressure amplitude refers to the actual pressure measured in the brake chamber or brake line, used to measure whether the brake air pressure has reached sufficient strength.

[0065] During the signal acquisition phase, in addition to acquiring air pressure signals and vehicle dynamic response signals, it is also necessary to acquire brake control command signals. Brake control command signals can be obtained from the brake controller output or the vehicle communication bus, and their corresponding timestamps are recorded as the brake control command moments. Air pressure signals are acquired through pressure sensors installed in the brake lines or brake chambers. Through time synchronization processing, the brake control command signals and air pressure signals are unified to the same time base.

[0066] Based on the determined pressure build-up time, the difference between the pressure build-up time and the braking control command time is calculated to obtain the air pressure build-up delay. For example, if the braking control command time is a certain point in time, and the air pressure signal reaches the preset effective pressure threshold for the first time after a period of rising after that point, the time difference between the two is taken as the air pressure build-up delay. Simultaneously, the air pressure amplitude is extracted from the air pressure signal; the air pressure amplitude can be the value after the brake chamber pressure reaches stability or the pressure peak during braking.

[0067] When determining whether the air pressure build-up characteristics meet the preset normal conditions, it is necessary to check two parameters simultaneously: air pressure build-up delay and air pressure amplitude. The preset normal conditions are that the air pressure build-up delay does not exceed the preset air pressure delay threshold, and the air pressure amplitude meets the preset effective pressure condition. The preset air pressure delay threshold can be determined based on calibration data of healthy vehicles of the same model, such as the average time from the issuance of the braking command to the air pressure reaching the effective level under the same operating conditions in a normal vehicle. The preset effective pressure condition can be set to the air pressure amplitude reaching a preset absolute pressure threshold, or it can be set to the air pressure amplitude reaching a preset proportion of the target pressure.

[0068] When the pressure build-up delay does not exceed the preset pressure delay threshold and the pressure amplitude meets the preset effective pressure condition, the pressure build-up characteristic is determined to meet the preset normal condition, indicating that the air supply link, brake valve, and brake pipeline of the braking system are working normally. Under this premise, the additional response delay and vehicle deceleration response characteristics can be further analyzed to determine whether there is an abnormality in the mechanical braking actuator.

[0069] When the pressure build-up delay exceeds the preset pressure delay threshold or the pressure amplitude does not meet the preset effective pressure condition, it indicates that there is an abnormality in the pressure build-up process. At this time, the prerequisite for entering the abnormality judgment of the mechanical actuator is not met.

[0070] In a preferred embodiment, in the method for identifying anomalies in a drum braking system based on air pressure and deceleration, when the air pressure build-up delay exceeds a preset air pressure delay threshold and / or the air pressure amplitude does not meet the preset effective pressure condition, it is determined that the air pressure build-up characteristic does not meet the preset normal condition, and it is determined that there is an air pressure build-up anomaly in the braking system.

[0071] In a specific embodiment of the present invention, after obtaining the air pressure establishment characteristics, it is necessary to judge whether the air pressure establishment delay and air pressure amplitude meet the normal conditions, and if they do not meet the conditions, it is clearly determined that there is an abnormality in the air pressure establishment of the braking system.

[0072] When the air pressure build-up delay exceeds the preset air pressure delay threshold, it indicates that the brake air pressure build-up speed is lower than normal. Possible causes include insufficient air reservoir pressure, slow response of the relay valve, or partial blockage in the brake lines. When the air pressure amplitude does not meet the preset effective pressure condition, it indicates that the braking system cannot provide sufficient braking pressure. Possible causes include leaks in the air supply line, excessively low air reservoir pressure, or abnormal brake valve output. If either or both of these conditions occur, the air pressure build-up characteristics are determined to not meet the preset normal conditions.

[0073] After determining that the air pressure build-up characteristics do not meet the preset normal conditions, it is further determined that there is an abnormality in the air pressure build-up of the braking system. This determination result directly points to the air pressure-related components of the braking system, such as the air supply link, brake valve, or air circuit, prompting maintenance personnel to check and maintain these components.

[0074] In a preferred embodiment, the method for identifying anomalies in a drum braking system based on air pressure and deceleration determines that the braking system has a mechanical braking execution end anomaly when the additional response delay increases relative to a preset reference response delay and / or the vehicle deceleration response characteristic degrades relative to a preset reference response. This includes determining that the braking system has a mechanical braking execution end anomaly when the additional response delay exceeds the preset reference response delay and / or the vehicle deceleration response characteristic is lower than the preset reference response.

[0075] In a specific embodiment of the present invention, when an abnormality is determined at the mechanical braking actuator, a direct threshold comparison method is used to compare the additional response delay with a preset reference response delay and to compare the vehicle deceleration response characteristics with a preset reference response.

[0076] The preset baseline response delay is a reference value characterizing the time interval between effective pressure build-up and effective deceleration under healthy conditions. This reference value can be determined statistically based on braking test data of healthy vehicles of the same model, or it can be set based on the initial test data of the target vehicle at the time of manufacture or the test data after maintenance confirming normal operation. For example, before the vehicle is put into use or after regular maintenance, perform one or more standard braking actions, record the additional response delay during each braking process, and take the average value or a reasonable upper limit as the preset baseline response delay.

[0077] The preset reference response is a reference value characterizing the deceleration response capability of a vehicle under healthy conditions. This reference value may include the preset reference deceleration and the preset reference pressure deceleration response gain. The preset reference deceleration can be set based on the stable deceleration achieved by a healthy vehicle under standard braking conditions, and the preset reference pressure deceleration response gain can be calculated and determined based on the deceleration produced by a healthy vehicle under the same braking pressure.

[0078] In actual diagnostics, the air pressure signal and vehicle dynamic response signal of the current braking event are acquired, and the current additional response delay and current vehicle deceleration response characteristics are extracted. The current additional response delay is directly compared with a preset reference response delay. If the current additional response delay exceeds the preset reference response delay, it is determined that the additional response delay has increased relative to the preset reference response delay. The current vehicle deceleration response characteristics are directly compared with a preset reference response. If the current actual deceleration is lower than the preset reference deceleration or the current pressure deceleration response gain is lower than the preset reference pressure deceleration response gain, it is determined that the vehicle deceleration response characteristics have degraded relative to the preset reference response.

[0079] The two judgment conditions mentioned above are parallel. When the additional response delay exceeds the preset reference response delay but the deceleration response characteristics do not degrade, it indicates that the mechanical execution process time has increased but the braking friction efficiency is still acceptable, possibly due to an increased gap between the brake pads and the brake drum. When the deceleration response characteristics are lower than the preset reference response but the additional response delay has not increased, it indicates that the mechanical execution process time is normal but the braking efficiency has decreased, possibly due to deterioration of the friction pad performance or deterioration of the brake drum surface condition. When both conditions are met simultaneously, it indicates that the mechanical actuator has degraded in both stroke and efficiency.

[0080] In a preferred embodiment, the method for identifying anomalies in a drum braking system based on air pressure and deceleration determines that the braking system has a mechanical braking execution end anomaly when the additional response delay increases relative to a preset reference response delay and / or the vehicle deceleration response characteristic degrades relative to a preset reference response. This includes: determining an additional delay response degradation parameter based on the additional response delay; determining a vehicle deceleration response characteristic degradation parameter based on the vehicle deceleration response characteristic; assigning weights to the additional delay response degradation parameter and the vehicle deceleration response characteristic degradation parameter respectively; performing a weighted summation of the additional delay response degradation parameter and the vehicle deceleration response characteristic degradation parameter to determine a mechanical anomaly evaluation parameter; and determining that the braking system has a mechanical braking execution end anomaly when the mechanical anomaly evaluation parameter exceeds a preset mechanical anomaly threshold.

[0081] In a specific embodiment of the present invention, when determining an abnormality in the mechanical braking actuator, a multi-parameter weighted comprehensive evaluation method is adopted. The additional response delay and the vehicle deceleration response characteristics are each quantified into degradation parameters, and then a unified mechanical abnormality evaluation parameter is obtained through weighted fusion to improve the reliability of the determination.

[0082] First, the additional delay response degradation parameter is determined based on the additional response delay. This parameter quantifies the deviation of the time interval between effective air pressure establishment and effective deceleration generation in the current braking event from a healthy state. A greater deviation results in a higher value for the additional delay response degradation parameter, indicating a more significant increase in the time consumed by the mechanical execution process.

[0083] Secondly, the degradation parameters of the vehicle deceleration response characteristics are determined based on the vehicle's deceleration response characteristics. These degradation parameters quantify the degree of decline in the mechanical actuator's responsiveness relative to a healthy state during the current braking event. The more significant the decline in responsiveness, the higher the value of this degradation parameter.

[0084] Then, weights are assigned to the additional delay response degradation parameter and the vehicle deceleration response characteristic degradation parameter, respectively. The weights can be determined based on the contribution or reliability of each parameter to the diagnosis of mechanical actuator anomalies. For example, in conditions such as mining areas with frequent braking, the change in the gap between the brake pads and brake drum has a significant impact on the additional response delay, so a larger weight can be assigned to the additional delay response degradation parameter; similarly, in conditions where friction pad performance degradation is the main degradation mode, a larger weight can be assigned to the vehicle deceleration response characteristic degradation parameter. The weights are typically set such that the sum of all weights is 1.

[0085] After weighting, the additional delay response degradation parameter and the vehicle deceleration response characteristic degradation parameter are weighted and summed to obtain the mechanical anomaly evaluation parameter. The mechanical anomaly evaluation parameter is a comprehensive indicator that integrates additional delay information from the time-series dimension and deceleration response information from the efficiency dimension. When both degradation parameters are small, the mechanical anomaly evaluation parameter is low, indicating that the mechanical actuator is close to a healthy state; when either degradation parameter increases or both increase simultaneously, the mechanical anomaly evaluation parameter increases accordingly.

[0086] Finally, the mechanical anomaly evaluation parameters are compared with preset mechanical anomaly thresholds. These thresholds can be determined statistically based on the normal fluctuation range of healthy vehicles of the same model, or set based on maintenance experience. When the mechanical anomaly evaluation parameters exceed the preset thresholds, it is determined that there is a mechanical brake actuator anomaly in the braking system.

[0087] Determining an anomaly based on a single parameter is susceptible to interference from signal noise, operating condition fluctuations, or sensor errors, potentially leading to false alarms or missed alarms. For example, when a vehicle is traveling on a bumpy road, wheel speed signals may experience brief fluctuations, causing momentary anomalies in deceleration response characteristics. In such cases, relying solely on this single parameter may result in a false alarm. This implementation quantifies the additional response delay and vehicle deceleration response characteristics as degradation parameters, and constructs mechanical anomaly evaluation parameters through weighted synthesis. Anomaly determination is only triggered when the combined score of degradation information from multiple dimensions exceeds a threshold, effectively reducing the risk of false alarms caused by fluctuations in a single parameter. Furthermore, the configurability of the weight parameters allows the diagnostic strategy to adapt to different vehicle models and operating conditions, improving the applicability of the diagnostic system.

[0088] In a preferred embodiment, the method for anomaly identification of a drum braking system based on air pressure and deceleration, wherein determining the additional delay response degradation parameter based on the additional response delay includes: determining the additional delay response degradation parameter based on the relative deviation of the additional response delay relative to a preset reference additional response delay.

[0089] In a specific embodiment of the present invention, when determining the additional delay response degradation parameter, a calculation method based on relative deviation is adopted to eliminate the absolute value differences caused by different vehicles or different reference conditions.

[0090] First, obtain the additional response delay corresponding to the current detection cycle. The additional response delay is the time difference between the deceleration establishment time and the pressure establishment time, reflecting the time elapsed from the effective establishment of brake air pressure to the vehicle generating effective deceleration. This value can be calculated in real time for each braking event.

[0091] Secondly, obtain the preset baseline additional response delay. The preset baseline additional response delay is a reference value characterizing the additional response delay under healthy conditions. It can be determined based on the initial test data of the target vehicle at the time of manufacture, the test data after maintenance confirming normal operation, or the calibration data of healthy vehicles of the same model. For example, before the vehicle is put into use, a standard braking test is performed, and the additional response delay during multiple braking processes is recorded. The average value is taken as the preset baseline additional response delay.

[0092] Next, the relative deviation of the additional response delay relative to the preset baseline additional response delay is calculated. The relative deviation is calculated by first determining the difference between the current additional response delay and the preset baseline additional response delay, and then dividing this difference by the preset baseline additional response delay. The resulting ratio is the relative deviation. For example, if the preset baseline additional response delay is 100 ms and the current additional response delay is 130 ms, the difference is 30 ms, and the relative deviation is 0.3% or 30%. This relative deviation is the additional delay response degradation parameter.

[0093] The advantage of using relative deviation as a degradation parameter is that the baseline additional response delay may vary between different vehicles or even the same vehicle at different times. If the absolute difference is used directly as the degradation parameter, the same absolute difference may indicate severe degradation on vehicles with a smaller baseline value, while it may fall within the normal fluctuation range on vehicles with a larger baseline value, leading to inconsistent degradation judgment standards. Relative deviation normalizes the degree of degradation, making the same degradation parameter threshold applicable to different vehicles, thus improving the comparability and consistency of diagnostic results.

[0094] A higher value for the additional delay response degradation parameter indicates a more severe deviation of the current additional response delay from the healthy state. This parameter will serve as one of the inputs for subsequent weighted comprehensive evaluation.

[0095] In a preferred embodiment, the method for anomaly identification of a drum braking system based on air pressure and deceleration, wherein determining the vehicle deceleration response feature degradation parameter based on the vehicle deceleration response feature includes: determining the vehicle deceleration response feature degradation parameter based on the relative deviation of the vehicle deceleration response feature relative to a preset reference response.

[0096] In a specific embodiment of the present invention, when determining the degradation parameters of vehicle deceleration response characteristics, a calculation method based on relative deviation is adopted to eliminate the influence of differences in benchmarks between different vehicles on the degradation determination results.

[0097] First, obtain the vehicle deceleration response characteristics corresponding to the current detection cycle. These characteristics characterize the ability of the mechanical actuator to generate deceleration after brake pressure is established, and can include actual deceleration and pressure-deceleration response gain. Actual deceleration can be extracted from the filtered vehicle longitudinal acceleration signal, and the pressure-deceleration response gain can be calculated as the ratio of brake pressure to actual deceleration.

[0098] Secondly, obtain the preset baseline response. The preset baseline response is a reference value characterizing the deceleration response of a vehicle in a healthy state. It can be determined based on the initial test data of the target vehicle at the time of manufacture, the test data after maintenance confirming normal operation, or the calibration data of healthy vehicles of the same model. For example, before the vehicle is put into use, a standard braking test is performed, and the actual deceleration and pressure-deceleration response gain achieved during multiple braking processes are recorded. The average value is taken as the preset baseline response.

[0099] Next, the relative deviation of the vehicle deceleration response characteristics relative to a preset reference response is calculated. Taking actual deceleration as an example, the difference between the preset reference deceleration and the current actual deceleration is first calculated, and then this difference is divided by the preset reference deceleration; the resulting ratio is the relative deviation. Taking pressure-deceleration response gain as an example, the difference between the preset reference gain and the current gain is first calculated, and then this difference is divided by the preset reference gain; the resulting ratio is the relative deviation. This relative deviation is the vehicle deceleration response characteristic degradation parameter.

[0100] Using relative deviation as a degradation parameter can unify the response characteristics of different dimensions or different benchmark levels into dimensionless proportional values. The braking performance of different vehicles may vary at the time of manufacture. If absolute values ​​are used for direct comparison, the same absolute difference may indicate severe degradation for high-performance vehicles, while it may be within the normal range for low-performance vehicles. Relative deviation normalizes the degree of degradation relative to its respective benchmark, making the judgment criteria consistent and comparable.

[0101] A higher value for the vehicle deceleration response characteristic degradation parameter indicates a more significant decline in current deceleration response capability relative to a healthy state. This parameter will serve as one of the inputs for subsequent weighted comprehensive evaluation.

[0102] In a preferred embodiment, the method for identifying anomalies in a drum braking system based on air pressure and deceleration determines that the braking system has a mechanical braking execution end anomaly when the additional response delay increases relative to a preset reference response delay and the vehicle deceleration response characteristics degrade relative to a preset reference response. This includes: acquiring multiple additional response delays and / or multiple vehicle deceleration response characteristics corresponding to multiple detection cycles; when the multiple additional response delays exceed the preset reference response delay starting from the first detection cycle and show a continuous increasing trend in multiple consecutive detection cycles after the first detection cycle, and / or when the multiple vehicle deceleration response characteristics are lower than the preset reference response starting from the second detection cycle and show a continuous degrading trend in multiple consecutive detection cycles after the second detection cycle, it is determined that the braking system has mechanical degradation related to abnormal clearance between the brake shoes and brake drum.

[0103] In a specific embodiment of the present invention, when it is determined that there is mechanical degradation in the braking system related to abnormal clearance between the brake shoes and the brake drum, the determination is not based on the results of a single detection cycle, but on the trend changes of additional response delay and vehicle deceleration response characteristics obtained from multiple consecutive detection cycles.

[0104] During vehicle operation, each braking event can be considered a detection cycle. During each braking event, the system acquires the current air pressure signal and vehicle dynamic response signal, calculates the additional response delay, and extracts the vehicle deceleration response characteristics. At the same time, it records information such as the timestamp, cumulative mileage, or cumulative number of braking events for that detection cycle, so as to sort and analyze the data from multiple cycles.

[0105] The system continuously records data for multiple detection cycles. For the additional response delay, the system continuously tracks its value changes starting from the first detection cycle. When the additional response delay first exceeds the preset baseline response delay at the beginning of a certain detection cycle, and shows a continuous increasing trend in subsequent consecutive detection cycles starting from that cycle, it indicates that the time interval between effective pressure establishment and effective deceleration is gradually lengthening, and this lengthening is not an occasional fluctuation but a unidirectional increase.

[0106] For the vehicle deceleration response characteristics, the system also continuously tracks the numerical changes from the first detection cycle. When the vehicle deceleration response characteristics first fall below the preset benchmark response at the beginning of a certain detection cycle, and show a continuous degradation trend in subsequent consecutive detection cycles starting from that cycle, it indicates that the deceleration response capability of the mechanical actuator is gradually decreasing, and this decrease is continuous.

[0107] The increasing trend of additional response delay and the deteriorating trend of vehicle deceleration response characteristics can be used individually or jointly as judgment criteria. When either trend is confirmed, it can be determined that the braking system has mechanical degradation related to abnormal clearance between brake pads and brake drums.

[0108] The reason for using a persistent trend as a key condition for determining abnormal brake shoe-drum clearance is that the increase in clearance between the brake shoes and the brake drum is a gradual wear process. With each braking cycle, the friction material of the brake shoes and the working surface of the brake drum gradually wear down, leading to a gradual increase in the clearance between the shoes and drum. This results in a gradual increase in the time it takes for the brake shoes to travel across the idle travel zone, and a gradual delay in braking response. This degradation exhibits a monotonically increasing trend over time, which differs from occasional signal fluctuations or single abnormal braking events. By introducing a multi-cycle persistent trend determination, the gradual degradation caused by brake shoe-drum clearance wear can be distinguished from other occasional mechanical anomalies.

[0109] In a preferred embodiment, in the method for identifying anomalies in a drum braking system based on air pressure and deceleration, the vehicle deceleration response characteristics include actual deceleration and / or pressure-deceleration response gain; wherein, the pressure-deceleration response gain is determined based on the ratio between actual deceleration and braking pressure.

[0110] In a specific embodiment of the present invention, the vehicle deceleration response characteristics include two parameters: actual deceleration and pressure-deceleration response gain, which can be used alone or together to characterize the ability of the mechanical actuator to generate deceleration after the brake air pressure is established.

[0111] Actual deceleration refers to the measured value of the vehicle's longitudinal deceleration during braking. This value can be obtained directly from an inertial measurement unit installed on the vehicle, or by differentiating the signals output by the vehicle speed sensor or wheel speed sensor. To eliminate signal noise, the raw deceleration signal can be low-pass filtered or averaged. Actual deceleration reflects the final output effect of the braking system, that is, the actual degree of deceleration achieved by the vehicle during braking. Under the same braking command and the same road conditions, the greater the actual deceleration, the stronger the braking system's execution capability.

[0112] Pressure-deceleration response gain is a parameter determined by the ratio of actual deceleration to braking pressure. Braking pressure can be obtained from a pressure sensor in the brake chamber or brake line, taking the value during the stable pressure phase of braking. Actual deceleration is the absolute value of the stable deceleration phase during the same braking process. Dividing the two yields the deceleration value per unit braking pressure, i.e., the pressure-deceleration response gain. This gain reflects the efficiency of the braking system in converting air pressure energy into mechanical braking effect. Under the same braking air pressure, a higher gain indicates better friction between the brake pads and brake drum, and a healthier mechanical transmission mechanism.

[0113] When extracting vehicle deceleration response characteristics, only the actual deceleration, only the pressure-deceleration response gain, or both can be extracted. When only the actual deceleration is extracted, the diagnostic system focuses on whether the final braking effect meets expectations; when only the pressure-deceleration response gain is extracted, the diagnostic system focuses on whether the braking efficiency is normal; when both are extracted, the diagnostic system can comprehensively evaluate the state of the mechanical actuator from both the effect and efficiency dimensions.

[0114] Actual deceleration and pressure-deceleration response gain have clear physical meanings and engineering interpretability. Actual deceleration directly corresponds to the braking effect perceived by the user, and its magnitude is directly related to braking safety. Pressure-deceleration response gain reflects the energy conversion efficiency of the braking system; a decrease in this gain usually indicates deterioration of the friction pair or jamming of the mechanical transmission mechanism. Maintenance personnel can determine the health status of the braking system and formulate targeted maintenance measures based on the specific changes in these two parameters.

[0115] Another objective of this invention is to provide an anomaly identification system for a drum braking system based on air pressure and deceleration, comprising: an acquisition module for acquiring air pressure signals and vehicle dynamic response signals of the braking system during braking; a determination module for determining a pressure build-up time based on the air pressure signals and a deceleration build-up time based on the vehicle dynamic response signals, wherein the pressure build-up time is the time when the air pressure reaches a preset effective pressure condition, and the deceleration build-up time is the time when the vehicle deceleration reaches a preset effective deceleration condition; a calculation module for determining an additional response delay based on the time difference between the pressure build-up time and the deceleration build-up time; an extraction module for acquiring air pressure build-up features characterizing the air pressure build-up process and vehicle deceleration response features characterizing the deceleration response process; and a judgment module for determining that there is an anomaly in the mechanical braking actuator of the braking system when the air pressure build-up features meet preset normal conditions, and the additional response delay increases relative to a preset reference response delay and / or the vehicle deceleration response features degrade relative to a preset reference response.

[0116] Example 1

[0117] The following is a specific embodiment used to illustrate the abnormal identification method and system of the drum braking system based on air pressure and deceleration described in this invention.

[0118] The identification method and steps of this scheme are as follows:

[0119] S1. Obtain the braking control command output by the vehicle braking control system and determine the command time t corresponding to the braking control command. cmd ;

[0120] S2. Obtain the pneumatic braking response information during the execution of the braking control command, and determine the pressure establishment time t when the pneumatic response reaches the preset effective pressure condition based on the pneumatic braking response information. P ;

[0121] S3. Obtain vehicle dynamic response information during the execution of braking control commands, and determine the deceleration establishment time t when the vehicle deceleration response reaches the preset effective deceleration condition based on the vehicle dynamic response information. A ;

[0122] S4, Establish time t based on pressure P With deceleration establishment time t A Determine the additional response delay Δt after pressure buildup. m ;

[0123] S5. Determine the air pressure build-up characteristics based on the air pressure braking response information, and determine the vehicle deceleration response characteristics based on the vehicle dynamic response information.

[0124] S6. Based on air pressure establishment characteristics, vehicle deceleration response characteristics, and additional response delay Δt m Determine the response stage of the braking anomaly;

[0125] S7. When the pressure build-up characteristics meet the preset normal conditions, the additional response delay Δt m When the delay increases relative to the preset reference and / or the vehicle deceleration response characteristics degrade relative to the preset reference response, it is determined that there is an abnormality in the mechanical braking actuator of the pneumatic drum braking system;

[0126] S8, based on the additional response delay Δt m At least one of the following can be used to determine whether there is mechanical degradation associated with abnormal clearance between brake pads and brake drums: the response relationship between pressure and vehicle deceleration and historical trends.

[0127] The pneumatic braking response information includes: air reservoir pressure; brake line pressure; relay valve output pressure; and brake chamber pressure.

[0128] The preset effective pressure conditions include: the air pressure value reaches the preset absolute pressure threshold; the air pressure value reaches the preset proportion of the target pressure; the air pressure change rate reaches the preset condition; and the air pressure value enters the preset stable pressure range.

[0129] Vehicle dynamic response information includes: vehicle speed; vehicle longitudinal acceleration; wheel speed; inertial measurement unit output; and vehicle positioning speed.

[0130] The preset effective deceleration conditions include: the absolute value of the vehicle's longitudinal deceleration reaches a preset deceleration threshold; the vehicle's longitudinal deceleration reaches a preset proportion of the target deceleration; the vehicle's speed reduction rate reaches a preset threshold; and the filtered vehicle deceleration continuously meets the preset conditions for a preset time.

[0131] t cmd The time of the braking control command is in milliseconds (ms).

[0132] Pressure build-up time t P The time when the air pressure reaches the effective pressure condition, in milliseconds (ms).

[0133] Where t is the current time (in ms), and τ is the preset duration threshold (in ms). When the braking air pressure P(t) first reaches the effective pressure threshold P... eff (Unit: kPa) and when the duration is greater than τ, determine t. P =t. Or,

[0134] When P(t) ≥ βP target Time to determine t P , where P target Target pressure, unit: kPa, β can be a calibration ratio between 0 and 1.

[0135] Deceleration build-up time t A The time when the vehicle reaches the effective deceleration condition, in milliseconds (ms).

[0136] When |a(t)| ≥ the effective deceleration threshold a th And lasting for τ a When the above is true, determine t. A =t; where τ a The preset duration threshold is in milliseconds (ms), and a(t) is the vehicle deceleration in m / s². To avoid false triggering by vibration and noise, low-pass filtering, moving average, or multi-source fusion can be performed first.

[0137] Pressure build-up delay t p :t p =t P -t cmd , Unit: ms.

[0138] Deceleration build-up delay ta :t a =t A -t cmd , Unit: ms.

[0139] Additional response delay Δt after pressure buildup m Δt m =t A -t P Or Δt m =t a -t p , Unit: ms.

[0140] In step S7, the preset baseline delay is determined according to the following methods: calibration data of healthy vehicles of the same model; health status data of the target vehicle at the time of manufacture; health status data of the target vehicle after maintenance; and historical valid health test data of the target vehicle.

[0141] For example, t p Basically stable, pressure amplitude normal, but Δt m A continuous increase indicates that the main increase in delay occurs between the effective establishment of air pressure and the achievement of effective vehicle deceleration. The physical processes corresponding to this time interval include the mechanical output of the brake chamber, the movement of the pushrod, the movement of the adjusting mechanism, the brake pads crossing their free travel, the contact of the friction pairs, and the establishment of effective braking force. Therefore, Δt m It can be used to characterize changes in the state of the mechanical braking actuator.

[0142] When the braking control command meets the preset normal conditions and the air pressure build-up delay t p When preset normal conditions are met, air pressure amplitude meets preset normal conditions, and vehicle deceleration response degrades, the confidence level for determining abnormalities in the mechanical braking actuator is increased. When the air pressure build-up delay t... p When the air pressure delay threshold is exceeded and / or the actual air pressure amplitude is lower than the preset pressure threshold, the abnormality is preferentially determined to be related to the air pressure establishment process, rather than directly determining the abnormality as an abnormality in the clearance between the brake pads and the brake drum.

[0143] Further, determine the braking pressure P. brake The pressure-deceleration response gain K between the vehicle deceleration a and the vehicle deceleration α a :K a =|a| / P brake , where P brake The unit of is kPa, the unit of a is m / s², and the unit of Ka is (m / s²). 2 ) / kPa. Under the same or comparable pressure conditions, K a As the braking pressure decreases, the vehicle deceleration per unit pressure also decreases. When the actual braking pressure meets the preset normal conditions, the pressure-deceleration response gain K... aThe gain K relative to the reference pressure-deceleration response base (Unit: (m / s)) 2 When the pressure (Δt / kPa) decreases, increase the confidence level for determining an anomaly at the mechanical braking actuator. m Increase and K a If the accuracy decreases, the reliability of mechanical anomaly identification will be further improved.

[0144] Based on the current additional response delay Δt m Additional response delay Δt compared to the baseline m,base (Unit: ms) Determine the additional delay degradation parameter D tm :D tm =(Δt m -Δt m,base ) / Δt m,base Based on the current pressure-deceleration response gain K a With reference pressure-deceleration response gain K base Determine the gain degradation parameter D k :D k =(K base -K a ) / K base .

[0145] Establish a mechanical anomaly evaluation parameter M (dimensionless) based on at least two anomaly characteristics: M = w1·D tm +w2·D k +w3·D a ; where D tm Additional response delay degradation parameter; D k D is the pressure-deceleration response gain degradation parameter. a The parameters represent vehicle deceleration degradation; w1, w2, and w3 are the corresponding weights. When the mechanical anomaly evaluation parameter M exceeds the preset mechanical anomaly threshold, the confidence level of the mechanical braking actuator anomaly is determined to have reached the preset condition.

[0146] In step S8, the additional response delay Δt for multiple detection cycles is recorded continuously. m And under the condition that the pressure establishment characteristics remain within the preset normal range, according to Δt m Based on the increasing trends of vehicle operating time, number of transport cycles, cumulative mileage, or cumulative braking times, the mechanical condition degradation trend related to the increase in clearance between brake shoes and brake drums is determined.

[0147] Increase the correlation between brake pad and brake drum clearance abnormalities when at least two of the following conditions are met: normal air pressure build-up delay; normal brake pressure amplitude; and additional response delay Δt. m Increase; pressure-deceleration response gain K aDecline; actual braking deceleration decreases; historical test results show a continuous deterioration trend.

[0148] Based on the response stage where the anomaly occurs, at least one of the following diagnostic results will be output: abnormal brake control command; abnormal brake air supply; abnormal brake valve or air circuit response; abnormal mechanical brake actuator; mechanical degradation related to abnormal clearance between brake shoes and brake drum; the cause of the anomaly is uncertain and a re-inspection is requested.

[0149] Furthermore, when an abnormality is detected for the first time at the mechanical braking actuator, the preset braking action is re-executed, and the Δt obtained from multiple detections is used as the basis for the action. m Consistency determines whether an anomaly has been confirmed.

[0150] In calculating Δt m Previously, time synchronization was performed on air pressure braking response information and vehicle dynamic response information to ensure that the pressure signal and vehicle dynamic response signal were based on a unified time reference. This could be achieved using a unified controller timestamp, CAN time correction, Ethernet time synchronization, GNSS unified time base, or fixed communication delay compensation.

[0151] Determine the deceleration establishment time t A Previously, low-pass filtering, moving average, Kalman filtering, or multi-source fusion processing were performed on vehicle dynamic response information.

[0152] Specifically, this method performs anomaly stratification diagnosis:

[0153] (1) Type A: Normal

[0154] t p Normal; P is normal; Δt m Normal; a is normal. The diagnosis is: System normal.

[0155] (2) Type B: Abnormal pressure build-up

[0156] t p Increase; or insufficient P; and a decrease simultaneously. Diagnostic priority is: gas supply system, relay valve, pipeline, leak.

[0157] (3) Type C: Abnormal mechanical actuator

[0158] t p Normal; P is normal; Δt m Increase; a decrease. Diagnosis: Abnormal mechanical brake actuator.

[0159] (4) Type D: Highly correlated hoof-drum gap anomaly

[0160] t p Normal; P is normal; Δt m Continuously increasing; K aThe decline continues; the historical trend continues to worsen. The diagnostic result is: increased confidence in the mechanical degradation associated with increased hoof-drum gap.

[0161] This invention can distinguish between abnormal air pressure build-up and abnormal mechanical braking actuators, no longer relying solely on a decrease in vehicle deceleration as the sole criterion for fault diagnosis. By utilizing the additional response delay between the air pressure build-up moment and the deceleration build-up moment, while assuming normal air pressure build-up characteristics, it enhances the mechanistic correlation between diagnostic results and mechanical actuators. Furthermore, by combining this with multi-cycle historical trend analysis, it improves the reliability of identifying abnormal brake pad and brake drum clearances and facilitates more targeted maintenance recommendations from remote maintenance systems.

[0162] Example 2

[0163] like Figure 8 As shown in the figure, this embodiment illustrates the complete process from data acquisition to diagnostic output.

[0164] S1 Data Acquisition: Acquires braking control commands, air pressure signals, and vehicle dynamic response signals.

[0165] S2 Determine the critical moment: Determine the braking command moment t cmd Pressure build-up time t P Deceleration establishment time t A .

[0166] S3 calculates timing parameters: based on formula t p =t P -t cmd t a =t A -t cmd and Δt m =t A -t P =t a -t p Calculate each delay parameter.

[0167] S4 Feature Extraction: The extracted physical features include pressure establishment features, pressure amplitude features, and pressure establishment delay t. p And deceleration response characteristics, pressure-deceleration gain K a Actual deceleration a.

[0168] S5 Benchmark Comparison: Compare the extracted feature parameters with the corresponding benchmark values ​​(t) p,base P base Δt m,base K base a base The comparison is performed. Among them, t p,base Base pressure establishment delay, in milliseconds (ms), pressure (P)base Reference air pressure amplitude, unit: kPa, Δt m,base Add a response delay to the baseline, K base For the reference pressure-deceleration response gain, a base Reference deceleration, unit: m / s² 2 .

[0169] S6 Response Phase Diagnosis (Layered Judgment):

[0170] This step involves screening step by step using a decision tree.

[0171] First, determine if the braking command is normal; if not, output "Type A Braking control command abnormal"; if yes, continue to determine "t". p Is it outside the normal range or is the pressure amplitude insufficient?; if yes, output "Type B Pressure Establishment Abnormality (Gas Supply, Valve, Gas Circuit)"; otherwise, continue to determine "Δt". m Whether to increase or K a "Has the deceleration decreased or has the actual deceleration decreased?"; If the judgment is yes, the output is "Type A: System Normal". If yes, further judgment is needed on "Whether the air pressure build-up characteristics are normal". If the air pressure build-up characteristics are abnormal, the output is "Type B: Valve-related Abnormality". If normal, the initial judgment is "Type C: Mechanical Brake Actuator Abnormality". Based on this, the process further judges "Whether the high correlation drum clearance abnormality condition is met". This high correlation condition must meet at least two of the following indicators: t p Normal, braking pressure amplitude is normal, Δt m Increase, K a Decrease, actual deceleration decrease, and continuous degradation of historical results; if this is the case, it is classified as "Type C Mechanical Abnormality (Non-Clearance Main Cause)"; otherwise, it is classified as "Type D Mechanical Degradation Related to Brake Pad and Brake Drum Clearance Abnormality".

[0172] S7 Output Diagnostic Results: The system output diagnostic results cover: abnormal braking control commands, abnormal air pressure build-up, abnormal valves or air circuits, abnormal mechanical brake actuators, mechanical degradation related to abnormal drum-hoof clearance, and abnormal causes that are uncertain and require re-inspection.

[0173] S8 Result Storage and Trend Analysis: Store key parameters, update trends, request re-inspection or provide maintenance suggestions when necessary, and the process ends here.

[0174] like Figure 1 The schematic diagram of the pneumatic drum brake response chain shown illustrates the series relationship of various physical actions during the response of the mining truck braking system. Figure 1The diagram uses 10 consecutive action frames to describe the complete transformation process from signal to braking effect, in the following order: Action 1: Brake control command output; Action 2: Brake valve actuation; Action 3: Air pressure enters the pipeline; Action 4: Brake chamber pressure build-up; Action 5: Air chamber output mechanical displacement; Action 6: Transmission mechanism pushes brake shoes; Action 7: Brake shoes cross the brake drum clearance (free travel); Action 8: Brake shoes contact the brake drum and establish effective friction; Action 9: Wheel generates braking torque; Action 10: Vehicle generates measurable deceleration. The corresponding physical actuators and their states are as follows: ECU / controller, electronically controlled brake valve / relay valve, brake pipeline, brake chamber pressure build-up, pushrod output mechanical displacement, adjustment mechanism movement, crossing the brake drum clearance (free travel), friction pair contact, effective braking force establishment, wheel braking torque generation, and vehicle deceleration formation. Figure 1 The complete response chain is clearly divided into three main response stages: "pneumatic system response" covering the first four actions, "mechanical actuator response" covering the middle four actions, and "vehicle dynamics response" covering the last two actions. This process is a complete response chain from control command to vehicle deceleration. This physical timing logic provides theoretical support for the anomaly identification method in Embodiment 1: namely, obtaining the action 1 corresponding to the braking control command in step S1; and determining the pressure establishment time t based on the pneumatic signal in step S2. P The deceleration settling time t, which corresponds to the completion time of action 4, is determined based on the vehicle's dynamic response. A This corresponds to the completion time of action 10. The resulting additional response delay Δt is then calculated. m =t A -t P Its physical meaning is the interval between the effective establishment of air pressure and the formation of vehicle deceleration, explicitly including the time consumed by the "mechanical actuator response" (actions 5 to 8) and part of the "vehicle dynamics response". Therefore, when the air pressure system response (i.e., air pressure establishment characteristics) is normal, the additional response delay Δt m When the vehicle deceleration response characteristics are increased or degraded, the abnormality can be accurately located to the mechanical actuator response action, thus providing a clear physical basis for the subsequent abnormal layer diagnosis in steps S6 to S8 (especially the identification of abnormalities in the drum-hoof gap).

[0175] like Figure 2 The timing diagram of braking command, pressure and deceleration shown not only intuitively demonstrates the dynamic changes of key signals of the mining truck over time during a single braking process, but also reveals the core working principle of this embodiment in decoupling fault links by utilizing "characteristic delay" from a physical perspective.

[0176] The four coordinate graphs in the figure depict the changes in braking control command (step output), braking air pressure P(t), vehicle deceleration a(t), and vehicle speed v(t) over time t. The target pressure P is marked on the curve of the braking air pressure P(t). target And the moment when the air pressure reaches the effective pressure condition, that is, when the air pressure first rises to the effective pressure threshold P. eff The time t corresponding to time P The decreasing curve of vehicle deceleration a(t) marks the moment when the vehicle deceleration reaches the effective deceleration condition, that is, when the absolute value of the deceleration first reaches the effective deceleration threshold a. th The time t corresponding to time A The coordinated changes of these three signal curves accurately reflect the complete energy transfer chain after the braking command is issued, including gas entering the pipeline, the movement of the air chamber push rod, the friction of the brake pads, and the deceleration of the entire vehicle.

[0177] Combination Figure 1 The response chain, t p Physically, this corresponds to the time consumed in the "pneumatic system response" phase (actions 1 to 4), reflecting the state of the air supply, pipelines, and brake valves. And from the formula Δt... m =t A -t P It can be seen that Δt m In terms of timing, the entire time consumed by the air pressure building process is removed, and in terms of physical timing, it corresponds to the time consumed by the "mechanical actuator response" stage (actions 5 to 8, including air chamber output, push rod movement, transmission mechanism pushing the shoe, crossing the shoe-drum gap and friction pair contact).

[0178] like Figure 3 As shown in the figure, the key moments required for time series analysis are clearly defined and physically represented. The vertical axis of the figure represents the three signals that vary with time t: braking control command u(t), braking pressure P(t), and vehicle deceleration a(t). The target pressure P is marked within the braking pressure P(t) signal. target and effective pressure threshold P eff It also precisely defines the moment t when the air pressure reaches the effective pressure condition. P In the vehicle deceleration a(t) signal, the effective deceleration threshold -a is marked. th It also precisely defines the time t when the vehicle deceleration reaches the effective deceleration condition. A .

[0179] at the same time, Figure 3 The timeline below directly marks the timing of the braking control command, the effective establishment of air pressure, and the effective establishment of deceleration on the timeline, and presents the corresponding air pressure establishment delay t. p Additional response delay Δt mand deceleration build-up delay t a .

[0180] Combination Figure 1 The revealed tandem response chain, t cmd Representing the triggering start point of the series response chain (i.e., the braking control command output), t P This represents the completion node of the "pressure system response" in the series response chain. And t A This represents the final point at which the vehicle's braking deceleration occurs. cmd With t P The difference t between p It characterizes the speed of a component in a pneumatic system; t P With t A The difference Δt between m It accurately characterizes the speed of the mechanical execution processes (including push rod movement, shoe clearance crossing, friction pair contact, etc.) after air pressure is established and before the vehicle deceleration is formed.

[0181] like Figure 4 As shown in the figure, this mainly illustrates the additional response delay Δt. m The calculation process is shown, and the physical principle of its role as the core indicator for "decoupling of pneumatic-mechanical actuation links" is revealed. The figure shows the three key signals, namely braking control command u(t), braking pressure P(t), and vehicle deceleration a(t), on the vertical axis.

[0182] t p It measures the time taken during the "pressure system response" phase; while Δt m The time consumed by the air pressure build-up process is completely excluded on the timeline; its physical process corresponds to the interval after effective air pressure build-up and before vehicle deceleration occurs. Based on this principle, the method in this embodiment utilizes the timing logic revealed in the diagram in subsequent diagnostics: when the air pressure build-up is delayed by t... p When maintaining normal operation and pressure amplitude meeting standards, if an additional response delay Δt is applied... m An increase in Δt indicates an abnormality in the mechanical actuator's response, such as an increased gap between the drum and the hoof, leading to increased idle stroke; if Δt m If the vehicle's deceleration response characteristics are normal but degraded, it indicates a decrease in the effectiveness of the friction pair.

[0183] like Figure 5 The normal state timing diagram illustrates the ideal synchronous response and normal distribution of characteristic parameters of the brake control command, brake pressure, vehicle deceleration, and vehicle speed during braking, assuming no braking anomalies occur. The diagram sequentially plots the brake control command u(t) increasing from 0 to 1, and the output time t of the brake control command. cmd Initiation response; the braking air pressure P(t) rises from 0, experiencing the target pressure P targetand effective pressure threshold P eff The corresponding air pressure reaches the effective pressure condition at time t P The vehicle deceleration a(t) begins to show a negative increase as air pressure builds up, reaching the effective deceleration threshold -a. th As a criterion, the time t when the vehicle deceleration reaches the effective deceleration condition is defined. A The vehicle speed v(t) simultaneously reflects the overall deceleration trend of the vehicle.

[0184] Combination Figure 1 In the series response chain, the pressure system response links (actions 1 to 4) are normal, meaning the pressure build-up delay t p Within the preset normal range, and the air pressure amplitude meets the standard; the mechanical actuator response (actions 5 to 8) is normal, i.e., the additional response delay Δt is normal. m Response delay Δt compared to preset baseline m,base The response remained consistent, with no additional idle travel or motion lag; the vehicle dynamics response (actions 9 to 10) was normal, i.e., the actual deceleration and pressure-deceleration response gain K were normal. a It conforms to the preset benchmark. When Figure 5 When all timing features meet their respective preset normal thresholds and baseline requirements, the drum braking system of the current vehicle can be directly determined to be in a healthy state. This figure serves as a baseline reference, providing a standard comparison chart with a clear physical mechanism for identifying abnormal air pressure build-up, abnormal mechanical actuators, and abnormal drum-hoof clearance in subsequent steps.

[0185] like Figure 6 The timing diagram for abnormal air pressure buildup (Type B) is shown in this embodiment. Specifically, this diagram illustrates the typical timing characteristics of the braking system when an abnormality occurs during air pressure buildup (i.e., a Type B abnormality). The diagram plots the changes in brake control command u(t), brake pressure P(t), vehicle deceleration a(t), and vehicle speed v(t) over time t, and defines the output time t of the brake control command. cmd The time t when the air pressure reaches the effective pressure condition P The time t when the vehicle deceleration reaches the effective deceleration condition A Key nodes, and the target pressure P, were also marked. target Effective pressure threshold P eff and effective deceleration threshold -a th .

[0186] Figure 6 The core physical characteristic of the "Type B anomaly" shown is that the time taken for the air pressure to reach the effective pressure condition after the braking command is issued is significantly increased. Combined with... Figure 1The response chain analysis pinpointed the anomaly to the "pneumatic system response" stage (actions 1 to 4). Its physical causes primarily included delayed brake valve response, leaks in the air supply line, or insufficient pressure in the air reservoir. The fault in the pressure build-up stage itself prolonged the initial stage of the entire braking response chain, thus affecting the subsequent deceleration build-up time t. A Passive delay. Under this abnormal mechanism, a delay t is established by determining the air pressure. p If the preset pressure delay threshold is exceeded and / or the pressure amplitude does not meet the preset effective pressure condition, the anomaly is directly locked in the pressure establishment stage, and the output type B: Diagnostic conclusion of pressure establishment anomaly.

[0187] like Figure 7 As shown in the figure, this embodiment specifically illustrates the typical timing response characteristics when the braking system experiences a Type C anomaly (i.e., an anomaly at the mechanical brake actuator). The figure sequentially plots the changes in brake control command u(t), brake pressure P(t), vehicle deceleration a(t), and vehicle speed v(t) over time t. Compared to the normal state, the figure shows the output time t of the brake control command. cmd Target pressure P target Effective pressure threshold P eff and effective deceleration threshold -a th If the pressure remains unchanged, the pressure curve will still be able to smoothly rise to the expected time until the pressure reaches the effective pressure condition at time t. P However, the vehicle deceleration curve shows a significant rightward shift, indicating that the vehicle deceleration reaches the effective deceleration condition at time t. A There was a significant lag.

[0188] Figure 7 This embodiment reveals the key physical characteristic that distinguishes between "pneumatic link failure" and "mechanical link failure": the pressure build-up delay t p Both air pressure amplitude and pressure remain within normal ranges, indicating Figure 1 The "baric system response" phase (actions 1 to 4) in the response chain is functioning normally; however, the additional response delay Δt m A significant increase indicates that the anomaly mainly occurred in the mechanical action range after the air pressure was effectively established and before the vehicle deceleration was formed. Figure 7 Δt m The increase physically maps to Figure 1 Actions 5 to 8 in the response chain include delays in mechanical links such as the push rod outputting mechanical displacement, the transmission mechanism pushing the shoe, crossing the shoe-drum gap (idle stroke), and the friction pair contacting and establishing effective friction. Based on this principle, when performing layered diagnosis in this embodiment, if the air pressure establishment characteristic is determined to meet the preset normal conditions (i.e., t... p (Normal air pressure amplitude), with an additional response delay Δtm When the response delay exceeds the preset baseline and / or the vehicle deceleration response characteristics degrade, the system can accurately output the diagnostic result "Type C: Mechanical brake actuator abnormality". This clearly prompts maintenance personnel to conduct targeted inspections and maintenance on mechanical components such as brake chambers, push rods, adjustment mechanisms, and brake pads, effectively avoiding the diagnostic deviation of misjudging mechanical abnormalities as pneumatic system abnormalities.

[0189] like Figure 9 As shown, this figure is used to quantitatively characterize the efficiency change of the mechanical actuator in the process of converting braking pressure into actual vehicle deceleration. The figure uses braking pressure P as the unit of measurement. brake The horizontal axis is denoted by 'a', and the vertical axis is denoted by 'vehicle deceleration |a|'. Dashed lines represent the baseline pressure-deceleration response curve (for healthy vehicles or initial healthy states), while solid lines represent the actual pressure-deceleration response curve (for current actual testing states). The specific test points are marked on the graph, with test pressure point 1 (P1, unit: kPa) and test pressure point 2 (P2, unit: kPa) shown sequentially. Comparing the two curves under the same braking pressure conditions, it is clear that the actual response is lower: at pressure P1, the corresponding deceleration decreases by Δa1 (m / s²); at pressure P2, the corresponding deceleration decreases by Δa2 (m / s²).

[0190] Figure 9 The downward shift of the revealed curve and the decrease in the gain slope directly reflect... Figure 1 The energy conversion efficiency of the "mechanical actuator response" (actions 5 to 8, i.e., the transmission mechanism pushing the shoe, bridging the shoe-drum gap, and establishing effective friction through friction pair contact) in the response chain. The text below the diagram precisely summarizes the engineering application principle of the diagram, namely: under the same braking pressure conditions: the actual deceleration decreases, or the gain K... a Relative to the reference gain K base A decrease indicates a reduction in deceleration per unit pressure, suggesting a degradation in the performance of the mechanical actuator. This means that, assuming the air pressure system is functioning normally, mechanical deterioration such as increased clearance between the brake pads and brake drum (leading to increased free travel), wear and tear on the friction pad surface, or jamming of the pushrod mechanism prevents the brake air pressure from being effectively converted into wheel braking torque and vehicle deceleration.

[0191] like Figure 10 As shown, this figure is specifically designed to illustrate the continuous degradation trend of characteristic parameters of the mechanical actuator as the number of braking events (running time / cumulative braking events) increases. The figure plots the additional response delay Δt from top to bottom. m Pressure build-up delay t p and pressure-deceleration gain K a The long-term trend of change over time. In Δt mThe time-series curve clearly divides the degradation into four distinct evolutionary stages: healthy stage (normal), early degradation stage (attention), mid-stage degradation stage (early warning), and late degradation stage (alarm). The figure also indicates the threshold benchmarks used for determining alarms and early warnings at each stage, including the severe anomaly threshold Δt. m,crit (Unit: ms), warning threshold Δt m,alarm (Unit: ms) and reference delay Δt m,base The air pressure in the middle establishes a delay t. p The curve provides the upper and lower limits of the normal range, but the range extends along the time axis from 0 to the end of the monitoring time window, T. 10 (Unit: ms) During the process, t p It consistently fluctuates within this normal range. The pressure-deceleration gain K at the bottom... a The curve clearly shows the reference gain K. base and early warning gain threshold K alarm (Unit: (m / s²) / kPa), and as time progresses towards T 10 Shift, actual gain K a It exhibits a clear and continuous downward trend. The gray area represents the degradation stage, Δt m It continues to increase, while t p K remains within the normal range a The continued decline indicates a persistent degradation trend in the mechanical actuator.

[0192] Figure 10 The degradation trend diagram reveals the core mechanism by which this embodiment identifies "mechanical degradation associated with abnormal brake shoe and brake drum clearance" (i.e., Type D). Combined with... Figure 1 The physical response chain, normal and long-term stable t p This indicates that the "air pressure system response" (actions 1 to 4) remains in good condition throughout the vehicle's lifespan; while the gray degradation area in the figure represents Δt. m It increases monotonically with the cumulative number of braking events, and K a The subsequent continuous decline in physical phenomena precisely maps the gradual degradation process of the "mechanical actuator response" (actions 5 to 8) in both the time domain and energy efficiency dimensions. Specifically, at the physical level, the long-term wear of the brake pad friction material and the brake drum working surface leads to a slow increase in the shoe-drum clearance, causing the pushrod to require a longer time to overcome the idle stroke after outputting mechanical displacement, thus causing Δt m The continuous increase in pressure; simultaneously, the aging and performance degradation of the contact friction surface lead to a decrease in the actual braking torque generated per unit braking pressure, resulting in K... a Continued decline.

[0193] like Figure 11 As shown, this embodiment provides an anomaly hierarchical diagnostic system. The system's physical architecture, from top to bottom, includes a data acquisition layer, a processing and computation layer, and an output and storage layer, and is deeply coupled with the application layer and the underlying baseline database. In actual deployment, the acquisition module in the drum brake system anomaly identification system based on air pressure and deceleration is... Figure 11 The diagram illustrates the implementation of the data acquisition layer in the anomaly hierarchical diagnostic system. This data acquisition layer is responsible for real-time acquisition of multi-source signals, specifically including braking control command u(t), air pressure signal P(t), vehicle speed signal v(t), acceleration signal a(t), and braking pressure P. brake Motor torque T m (Unit: N·m), SOC signal (unit: %), ambient temperature T env (Unit: °C) and vehicle load (M) load Physical quantities such as (unit: kg).

[0194] The determination and calculation modules in the anomaly identification system of a drum braking system based on air pressure and deceleration are composed of... Figure 11 The anomaly hierarchical diagnostic system shown is implemented in the timing parameter calculation module within the processing and computation layer. This module calculates and extracts the critical moments required to determine the system based on the raw signals input from the data acquisition layer: t cmd t P t A t a Based on this, the pressure build-up delay t is further calculated. p Deceleration build-up delay t a and additional response delay Δt m The extraction module of the drum braking system anomaly identification system based on air pressure and deceleration consists of... Figure 11 The feature extraction module in the processing and computation layer of the anomaly hierarchical diagnostic system shown is implemented here. This module is responsible for multi-dimensional feature extraction of air pressure and dynamic response signals, and the results include air pressure establishment features, air pressure amplitude features, and air pressure establishment delay t. p Deceleration response characteristics, pressure-deceleration gain K a And the actual deceleration a.

[0195] The judgment module in the anomaly identification system of the drum braking system based on air pressure and deceleration is composed of... Figure 11 The anomaly hierarchical diagnosis system shown is implemented jointly by the benchmark comparison module and the hierarchical diagnosis module in the processing and calculation layer. First, the benchmark comparison module compares the feature parameters extracted in the previous step with the preset benchmark value t. p,base P base Δt m,base K base a baseThe comparison and evaluation are performed; subsequently, the hierarchical diagnosis module performs diagnostic judgments of type A, type B and type C according to the hierarchical progression principle based on the comparison results.

[0196] During calculation and judgment, the processing and computation layer needs to access the underlying benchmark database (vehicle / operating condition matching) through bidirectional parameter matching and invocation (as shown by the bidirectional dashed arrows in the diagram). This benchmark database consists of four sub-databases: a benchmark parameter database storing various judgment thresholds (including t...). p,base P base Δt m,base K base a base The system includes: a vehicle configuration database that stores inherent vehicle information (covering vehicle model, braking system configuration, load rating, tire specifications, etc.); a working condition database that describes environmental characteristics (covering working conditions such as slope, road conditions, temperature, and altitude); and a historical case database that accumulates past experience (including various abnormal cases and diagnostic experience).

[0197] Once the layered diagnostic module completes its assessment, the diagnostic results flow into the output and storage layer. This layer first provides a clear conclusion—"Normal / Type A / Type B / Type C / Valve Circuit Abnormal / Mechanical Abnormal / Other Abnormal"—through the diagnostic result output module. Then, the visualization module presents the results to maintenance personnel in the form of time-series curves, trend charts, diagnostic conclusions, and recommended measures. Simultaneously, the data storage module records raw data, calculation results, historical trends, and diagnostic records, forming a closed-loop data accumulation. If the system detects an abnormality or even a serious defect, the alarm and notification module will trigger audible and visual alarms, platform push notifications, and maintenance prompts. Finally, all the diagnostic results and maintenance alarms are pushed to the remote application layer, connecting to different terminals—including the vehicle-mounted display terminal for driver reference, the cloud platform for data aggregation, and the backend maintenance and diagnostic terminal for technicians.

[0198] Figure 11 The application instructions in the lower right corner further explain the semantics of the symbols in the diagram: solid arrows represent data flow, double-headed dashed arrows represent parameter matching / calling, and dashed boxes define each independent functional module. This architecture strictly follows the logical flow of steps S1 to S8 in Example 1 of this embodiment, ensuring the engineering implementation of the anomaly layering diagnosis method in actual mining card systems. Figure 11 Block diagram of the anomaly hierarchical diagnostic system.

[0199] like Figure 12As shown, this embodiment constructs a complete diagnostic network system covering the vehicle end, cloud end, and on-site operation and maintenance end in actual engineering deployment. Within the vehicle / equipment end, the system consists of a display and interaction layer, an on-board diagnostic main control unit, a communication module, an on-board data acquisition layer, a sensor layer, and an actuator layer, from top to bottom. The actuator layer includes physical devices such as brake valves, air pressure regulating valves, motors / inverters, buzzers / indicator lights, etc., and performs action control downwards through the execution control signals indicated by the dashed arrows. The sensor layer uses hardware devices such as air pressure sensors, vehicle speed sensors, acceleration sensors, pressure sensors, and temperature sensors to achieve multi-dimensional signal acquisition of vehicle dynamics and braking status. The on-board data acquisition layer integrates control units such as the braking system ECU, air pressure controller, motor controller, and instrument / gateway, providing standardized data for upper-level calculations. The on-board diagnostic control unit (VCU) is centered around a diagnostic controller (VCU / Diagnostic Controller), responsible for coordinating local status monitoring and initial anomaly identification. It is also connected to a display and interaction module (including an on-board display terminal and an audible and visual alarm) for local alarm and result display, and a communication module (4G / 5G communication module) for data uploading to the cloud. Vehicle-side data is processed and forwarded via the internet / dedicated network through an edge computing gateway before being uploaded to the cloud-based diagnostic platform. The cloud-based diagnostic platform, powered by a cloud platform server, provides comprehensive cloud services including data storage and management, diagnostic analysis and modeling, and remote monitoring and alarms. The analyzed diagnostic results and alarm signals are then pushed to application clients via the internet / dedicated network for viewing on PC clients, mobile devices (APP), and maintenance diagnostic terminals. Furthermore, the system also deploys a field maintenance terminal, enabling tablet terminals, engineer computers, maintenance tools, and engineers / maintenance personnel to directly access the network for on-site data retrieval and rapid maintenance. Figure 12 The legend in the lower right corner clearly defines the symbols: solid arrows represent data flow, dashed arrows represent control flow, and dashed boxes indicate functional modules. This network architecture horizontally connects edge computing on the vehicle side with cloud-based collaborative analysis, and vertically spans the entire chain from signal acquisition and diagnostic calculation to execution layer output, effectively supporting the real-time deployment and remote, efficient operation and maintenance of the anomaly identification method for the mining truck drum braking system in this embodiment.

[0200] The following examples use the method and system of Example 1 to identify anomalies in a mine truck drum braking system.

[0201] Example 3: Normal State

[0202] A mining truck is performing a standard braking action. The measured value is: t cmd =0 ms; t P =180 ms; t A =310 ms.

[0203] Then: tp =180 ms; t a =310 ms; Δt m =130 ms.

[0204] The vehicle health benchmark Δt m,base =125 ms. Current Δt m If the values ​​are close to the health baseline, the condition is considered normal.

[0205] Example 4: Abnormal Pressure Establishment

[0206] Measured: t cmd =0 ms; t P =420 ms; t A =560 ms.

[0207] Then: t p =420 ms; Δt m =140 ms.

[0208] Because the main abnormal manifestation is t p The time increased from approximately 180 ms in the healthy state to 420 ms, while Δt m The pressure did not increase significantly, therefore the primary concern is an abnormality in the pressure build-up process. It is recommended to check the relay valve, gas lines, supply pressure, and for leaks.

[0209] Example 5: Abnormality at the mechanical actuator end

[0210] Measured: t cmd =0 ms; t P =185 ms; t A =480 ms.

[0211] Then: t p =185 ms; Δt m =295 ms.

[0212] Compared to a healthy state, barometric pressure establishment was essentially normal, but the additional response delay after pressure establishment increased from approximately 125 ms to 295 ms. Therefore, it was determined that the increased delay primarily occurred after effective barometric pressure establishment. Further analysis, combined with normal actual pressure and K... a A decrease in both the descent rate and the actual deceleration rate increases the confidence level of the mechanical braking actuator in case of anomalies.

[0213] Example 6: Historical Trend Identification

[0214] Δt was obtained through continuous detection m : 128 ms, 135 ms, 149 ms, 168 ms, 195 ms, 228 ms.

[0215] Same period t p: 181 ms, 179 ms, 184 ms, 180 ms, 183 ms, 182 ms.

[0216] It is evident that the pressure build-up delay remains stable over a long period, but the additional response delay after pressure build-up continuously increases. Based on this, the system determines that the mechanical actuator exhibits a continuous degradation trend. If K is detected simultaneously... a A continued decline further enhances the abnormal association with the increase in the hoof-drum gap.

[0217] Example 7: Comprehensive Mechanical Anomaly Index

[0218] Definition: D tm =(Δt m -Δt m,base ) / Δt m,base ;D k =(K base -K a ) / K base ;D a =(a base -a) / a base .

[0219] Establishment: M=w1D tm +w2D k +w3D a For example, w1=0.5, w2=0.3, w3=0.2. The above weights are merely examples and do not constitute a limitation on the scope of protection.

[0220] When M > preset mechanical anomaly threshold M th At that time, the system outputs "mechanical brake actuator abnormality".

[0221] When t is satisfied simultaneously p Normal, P is normal, Δt m Continued growth, K a When the brake pads continue to drop, the output will show "Mechanical degradation related to abnormal brake pad-brake drum clearance. It is recommended to check the brake pad-drum clearance, adjustment mechanism, and brake chamber push rod stroke".

[0222] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Other modifications can be readily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A method for anomaly identification in a drum braking system based on air pressure and deceleration, characterized in that, include: Acquire air pressure signals and vehicle dynamic response signals of the braking system during the braking process; The pressure establishment time is determined based on the air pressure signal, and the deceleration establishment time is determined based on the vehicle dynamic response signal. The pressure establishment time is the moment when the air pressure reaches the preset effective pressure condition, and the deceleration establishment time is the moment when the vehicle deceleration reaches the preset effective deceleration condition. The additional response delay is determined based on the time difference between the pressure establishment time and the deceleration establishment time; Obtain air pressure build-up characteristics that characterize the air pressure build-up process, and obtain vehicle deceleration response characteristics that characterize the deceleration response process; When the air pressure build-up characteristic meets the preset normal conditions, and the additional response delay increases relative to the preset reference response delay and / or the vehicle deceleration response characteristic degrades relative to the preset reference response, it is determined that there is an abnormality in the mechanical braking execution end of the braking system.

2. The method for anomaly identification of a drum braking system based on air pressure and deceleration according to claim 1, characterized in that, The air pressure establishment feature includes air pressure establishment delay and air pressure amplitude, wherein the air pressure establishment delay is the time difference between the air pressure establishment time and the braking control command time; The pressure establishment feature meets preset normal conditions, including: the pressure establishment delay does not exceed a preset pressure delay threshold, and the pressure amplitude meets preset effective pressure conditions.

3. The method for anomaly identification of a drum braking system based on air pressure and deceleration according to claim 2, characterized in that, When the pressure build-up delay exceeds the preset pressure delay threshold and / or the pressure amplitude does not meet the preset effective pressure condition, it is determined that the pressure build-up feature does not meet the preset normal condition, and it is determined that there is an abnormal pressure build-up in the braking system.

4. The method for anomaly identification of a drum braking system based on air pressure and deceleration according to claim 1, characterized in that, When the additional response delay increases relative to the preset reference response delay and / or the vehicle deceleration response characteristic degrades relative to the preset reference response, it is determined that there is an abnormality in the mechanical braking actuator of the braking system, including: When the additional response delay exceeds the preset baseline response delay and / or the vehicle deceleration response characteristic is lower than the preset baseline response, it is determined that there is an abnormality in the mechanical braking execution end of the braking system.

5. The method for anomaly identification of a drum braking system based on air pressure and deceleration according to claim 1, characterized in that, When the additional response delay increases relative to the preset reference response delay and / or the vehicle deceleration response characteristic degrades relative to the preset reference response, it is determined that there is an abnormality in the mechanical braking actuator of the braking system, including: The additional delay response degradation parameter is determined based on the additional response delay; Determine the vehicle deceleration response characteristic degradation parameters based on the vehicle deceleration response characteristics; Weights are assigned to the additional delay response degradation parameter and the vehicle deceleration response characteristic degradation parameter, respectively. The additional delay response degradation parameter and the vehicle deceleration response characteristic degradation parameter are then weighted and summed to determine the mechanical anomaly evaluation parameters. When the mechanical anomaly evaluation parameters exceed the preset mechanical anomaly threshold, it is determined that there is an anomaly in the mechanical braking execution end of the braking system.

6. The method for anomaly identification of a drum braking system based on air pressure and deceleration according to claim 5, characterized in that, The step of determining the additional delay response degradation parameter based on the additional response delay includes: The additional delay response degradation parameter is determined based on the relative deviation of the additional response delay from the preset baseline additional response delay.

7. The method for anomaly identification of a drum braking system based on air pressure and deceleration according to claim 5, characterized in that, The step of determining the vehicle deceleration response characteristic degradation parameter based on the vehicle deceleration response characteristics includes: The degradation parameter of the vehicle deceleration response characteristic is determined based on the relative deviation of the vehicle deceleration response characteristic relative to the preset reference response.

8. The method for anomaly identification of a drum braking system based on air pressure and deceleration according to claim 1, characterized in that, When the additional response delay increases relative to the preset reference response delay and the vehicle deceleration response characteristics degrade relative to the preset reference response, it is determined that there is an abnormality in the mechanical braking actuator of the braking system, including: Acquire multiple additional response delays and / or multiple vehicle deceleration response characteristics corresponding to multiple detection cycles; When the plurality of additional response delays exceed the preset baseline response delay starting from the first detection period, and show a continuous increasing trend in multiple consecutive detection periods after the first detection period, and / or When the deceleration response characteristics of the multiple vehicles fall below the preset benchmark response starting from the second detection cycle, and show a continuous degradation trend in multiple consecutive detection cycles after the second detection cycle, The braking system was found to have mechanical degradation related to abnormal clearance between the brake shoes and brake drum.

9. The method for anomaly identification of a drum braking system based on air pressure and deceleration according to any one of claims 4 to 8, characterized in that, The vehicle deceleration response characteristics include actual deceleration and / or pressure-deceleration response gain; wherein, the pressure-deceleration response gain is determined based on the ratio between actual deceleration and braking pressure.

10. An anomaly detection system for a drum braking system based on air pressure and deceleration, characterized in that, include: The acquisition module is used to acquire the air pressure signal and vehicle dynamic response signal of the braking system during the braking process; The determination module determines the pressure establishment time based on the air pressure signal and the deceleration establishment time based on the vehicle dynamic response signal, wherein the pressure establishment time is the moment when the air pressure reaches a preset effective pressure condition, and the deceleration establishment time is the moment when the vehicle deceleration reaches a preset effective deceleration condition. The calculation module is used to determine the additional response delay based on the time difference between the pressure establishment time and the deceleration establishment time; The extraction module is used to obtain air pressure build-up features characterizing the air pressure build-up process and vehicle deceleration response features characterizing the deceleration response process. The determination module is used to determine that there is an abnormality in the mechanical braking actuator of the braking system when the air pressure establishment feature meets the preset normal conditions, and the additional response delay increases relative to the preset reference response delay and / or the vehicle deceleration response feature degrades relative to the preset reference response.

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