Tire underpressure proportion monitoring method based on indirect tire pressure monitoring system

Abstract

The application provides a tire underpressure proportion monitoring method based on an indirect tire pressure monitoring system. The method is based on an existing indirect tire pressure monitoring algorithm, and the detection results of a tire relative rolling radius model and a tire vibration frequency spectrum model are comprehensively calculated. Meanwhile, a single-wheel underpressure rapid analysis module is comprehensively calculated, and finally an estimated value of tire underpressure proportion is obtained. A display module is used to display the actual vehicle speed, the underpressure proportion of each tire and the underpressure degree of the tire in real time. The above process can fully exert the advantages of the indirect tire pressure monitoring system, realizes the visualization of tire pressure without the aid of additional sensors or other equipment, and effectively improves the driving safety.

Description

Technical Field

[0001] This invention relates to the field of automotive tire pressure monitoring technology, and in particular to a method for monitoring the proportion of tire underpressure based on an indirect tire pressure monitoring system. Background Technology

[0002] Currently, tire pressure monitoring systems (TPMS) used in vehicles mainly include indirect and direct TPMS. Indirect TPMS uses an ECU (Electronic Control Unit) to determine tire pressure using a specific algorithm, offering advantages such as low cost and simple structure. However, because it doesn't require additional pressure or temperature sensors and relies solely on algorithms, it cannot display tire pressure status in real time. Direct TPMS directly measures tire pressure by installing a pressure sensor inside the tire or on the valve stem. The measured pressure data is transmitted wirelessly to a receiver and then displayed on a monitor or through sound or light. However, it suffers from short sensor lifespan and high cost. While both types of TPMS have their advantages, in practical applications, only one system can be selected to monitor tire pressure. Therefore, it's impossible to simultaneously provide both intuitive monitoring and real-time display of specific tire pressure values ​​or status. Thus, improving existing TPMS systems is of significant practical importance for tire pressure monitoring.

[0003] In view of this, it is necessary to design an improved method for monitoring tire underpressure ratio based on an indirect tire pressure monitoring system to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a method for monitoring the proportion of tire underpressure based on an indirect tire pressure monitoring system.

[0005] To achieve the above-mentioned objectives, this invention provides a method for monitoring tire underinflation ratio based on an indirect tire pressure monitoring system. The method is implemented through a PLG system, which includes a tire rolling characteristic monitoring module, a comprehensive calculation module, and a display module. The tire rolling characteristic monitoring module is used to realize signal output and processing, relative rolling radius monitoring, tire vibration spectrum monitoring, and single-wheel monitoring under all working conditions. The comprehensive calculation module is used to comprehensively analyze the relative rolling radius characteristics and tire vibration spectrum characteristics, and calculate the estimated value of tire underinflation ratio accordingly. The display module is used to display the actual vehicle speed, the underinflation ratio of each tire, and the degree of tire underinflation.

[0006] The PLG system sends the calculation results of the integrated calculation module to the vehicle instrument panel or central control interface through the vehicle CAN network. The calculation results are based on the existing indirect tire pressure monitoring algorithm, and are obtained by integrating the monitoring results of the tire relative rolling radius model and the tire vibration frequency spectrum model, as well as the data calculation of the single-wheel underpressure rapid analysis module.

[0007] Preferably, the steps include:

[0008] S1. The indirect tire pressure monitoring system integrated into the vehicle's ABS or ESC continuously collects timestamp signals from wheel speed sensors and vehicle CAN signals, and further calculates and analyzes the relative rolling radius value of the tires based on the collected signals. When the vehicle is driving under conditions that cause a change in the relative rolling radius value of the tires in a non-under-pressure state, or when all four wheels are under-pressured in the same proportion, pattern recognition and calculation are required.

[0009] S2, Based on the tire relative rolling radius value calculated in step S1, and the corresponding tire spectrum monitoring value F re (ij) and the monitoring value T of the corresponding tire rolling radius re (ij), calculate the comprehensive ratio value K, K(ij)=T re (ij)+S com (ij), where i = 0 or 1, 0 represents the front axis, 1 represents the rear axis, j = 0 or 1, 0 represents the left side, 1 represents the right side; S com (ij) represents the combined proportional compensation value between the front and rear axles, S com (ij)=[S com (i)+S com( j)];

[0010] S3. After a single wheel experiences rapid underpressure, the indirect tire pressure monitoring system will send an underpressure alarm flag to the PLG system within a preset time. Upon receiving the flag signal, the PLG system immediately identifies the current state as a single-wheel rapid underpressure and replaces the overall proportional calculation value with the calculation value from the single-wheel rapid alarm module. At this time, the PLG system needs to input the flag signal, and K(ij) = T. re (ij);

[0011] S4. Based on the actual underinflation ratio of the tire, fit the actual underinflation ratio of the tire using the comprehensive ratio calculation value K(ij) obtained in the previous steps. The tire pressure fitting value P(ij) is P(ij) = K(ij) + ΔK*f(Δk), where K(ij) is the comprehensive ratio calculation value of each tire rolling characteristic, ΔK is the tire underinflation ratio, and f(Δk) is the correction function. Use the tire pressure fitting value to determine the tire underinflation status, and display the underinflation status through the vehicle instrument panel or center console system working mode settings.

[0012] Preferably, in step S2, Among them, T drop F is an inherent characteristic value of the relative rolling radius. dropΔF is the inherent characteristic value of the tire vibration spectrum, ΔF is the change value of the tire vibration spectrum after underpressure, and ΔT is the amplified change value of the relative rolling radius.

[0013] Preferably, in step S1, the pattern recognition and calculation are performed in the following manner:

[0014] (1) Based on the original wheel speed timestamp signal generated by the vehicle wheel speed sensor, the tire vibration frequency spectrum characteristics related to the tire pressure can be obtained after processing such as eliminating sensor tooth ring error, interpolation, and extracting wheel speed signal vibration characteristics.

[0015] (2) The calculation algorithm in step S2 is used to comprehensively analyze the monitoring results of the relative rolling radius module and the vibration spectrum module, and the results of the comprehensive analysis are used for the design of the tire pressure alarm strategy and to characterize the actual tire underpressure condition; during the characterization of the tire underpressure condition, the display module that works with the vehicle tire pressure monitoring system is used to display the tire rolling status and the tire underpressure ratio.

[0016] Preferably, in step S2, when the vehicle is moving, a spectral change influence factor F is introduced. sta As a standard for determining whether a tire is underinflated, F sta The calculation formula is Where m and n are weighting parameters, whose values ​​are set according to the vehicle model and are related to factors such as the magnitude of the influence of loading on the wheel rolling characteristics. They are used to allocate the spectral influence weights, where m>n and m+n=1.

[0017] Preferably, when S com (i)≥P set And F sta <Q set At that time, it is assumed that K(ij) = F re (ij), and determined that the change in rolling radius was caused by loading, and that no tire underinflation actually occurred.

[0018] Preferably, in step S4, the expression for the correction function f(Δk) is:

[0019]

[0020] Preferably, the relative rolling radius change value ΔT = α*R re , where R re It represents the physical value of the change in the relative rolling radius of the tire, where α is the amplification factor, and the value of α is determined by the vehicle type.

[0021] Preferably, the system operating mode includes the following:

[0022] Mode 0: PLG is disabled, and there is no display of the tire pressure ratio or tire pressure level; this mode only provides basic indirect tire pressure monitoring alarm function; when the tire pressure is low, the system only issues a low pressure warning and indicates the location of the alarm tire.

[0023] Mode 1: Delayed display of tire pressure level. The tire pressure level is displayed after a certain period of time following the alarm, and the tire pressure level cannot be changed. In this mode, after a tire pressure alarm is triggered, the system will display the current tire pressure level after a short processing period. This pressure level reflects the tire pressure status at the moment the pressure alarm is issued, and will not be updated as the tire pressure continues to decrease.

[0024] Mode 2: Dynamically displays the tire pressure level. The tire pressure level is displayed immediately after the alarm is triggered and will change according to the analysis of TDA and FDA. In this mode, after the tire pressure is low and the system issues a low pressure alarm, the PLG will immediately calculate and display the tire pressure low ratio and the degree of low pressure. Afterwards, if the tire pressure continues to be low, the PLG will continue to calculate and update the tire pressure low ratio and the degree of low pressure in real time.

[0025] Mode 3: Real-time tire pressure ratio display, showing the tire pressure ratio at any time; in this mode, the system will continuously calculate and display the tire pressure ratio and degree of tire deflation, regardless of whether tire underinflation occurs.

[0026] Preferably, when the actual underinflation ratio ΔK of the tire exceeds 40%, the underinflation ratio display value is appropriately increased using the correction function f(Δk).

[0027] The beneficial effects of this invention are:

[0028] This invention proposes a tire underpressure ratio monitoring method based on an indirect tire pressure monitoring system. This method, based on existing indirect tire pressure monitoring algorithms, integrates the detection results from the tire relative rolling radius model and the tire vibration frequency spectrum model. Simultaneously, it incorporates a single-wheel underpressure rapid analysis module to ultimately derive an estimated tire underpressure ratio. A display module then shows the actual vehicle speed, the underpressure ratio of each tire, and the degree of underpressure in real time. This process fully leverages the advantages of the indirect tire pressure monitoring system, achieving tire pressure visualization without the need for additional sensors or other equipment, effectively improving driving safety. Attached Figure Description

[0029] Figure 1 This is a flowchart of the PLG system for the tire underpressure ratio monitoring method based on the indirect tire pressure monitoring system of the present invention.

[0030] Figure 2 for Figure 1 A detailed workflow diagram;

[0031] Figure 3 The display module shows the results when the tire underpressure ratio monitoring method based on the indirect tire pressure monitoring system of the present invention is applied. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0034] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, scheme, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, scheme, article, or apparatus.

[0035] Please see Figures 1 to 3 As shown, this invention provides a method for monitoring tire underpressure ratio based on an indirect tire pressure monitoring system. This method is implemented through a PLG system, which includes a tire rolling characteristic monitoring module, a comprehensive calculation module, and a display module. The tire rolling characteristic monitoring module is used for signal output and processing, relative rolling radius monitoring, tire vibration spectrum monitoring, and single-wheel monitoring under all working conditions. The comprehensive calculation module is used to comprehensively analyze the relative rolling radius characteristics and tire vibration spectrum characteristics, and calculate an estimated value for the tire underpressure ratio accordingly. The display module is used to display the actual vehicle speed, the underpressure ratio of each tire, and the degree of tire underpressure. This method is based on existing indirect tire pressure monitoring algorithms, comprehensively calculating the monitoring results of the tire relative rolling radius model and the tire vibration frequency spectrum model, while also comprehensively calculating the single-wheel underpressure rapid analysis module. The comprehensive calculation result obtained by this algorithm is the estimated value of the tire underpressure ratio, which is approximately the same as the actual tire underpressure ratio and can be used to reflect the tire underpressure state. The PLG system sends the comprehensively calculated tire rolling state and tire underpressure ratio to the vehicle instrument panel or central control interface via the vehicle's CAN network.

[0036] Specifically, the above comprehensive calculation includes the following steps:

[0037] S1. Signal input and tire rolling feature extraction:

[0038] The indirect tire pressure monitoring system integrated into the vehicle's ABS or ESC continuously collects timestamp signals from wheel speed sensors and vehicle CAN signals. Based on the collected signals, it further calculates and analyzes the tire's relative rolling radius value. These signals include: engine / motor speed signal, engine / motor torque signal, braking signal, lateral acceleration signal, longitudinal acceleration signal, yaw rate signal, etc. Under national standard operating conditions, the physical value R of the tire's relative rolling radius change is... re The corresponding tire underinflation ratio P re The relationship is linear, but under special conditions, such as extreme uneven loading, the relative rolling radius of the tires in the non-underpressure state may change. However, when all four tires are underpressured in the same proportion, the relative rolling radius of the tires will not change. For these conditions, pattern recognition and special calculations are required.

[0039] Furthermore, pattern recognition and special computations are achieved in the following ways:

[0040] (1) Based on the original wheel speed timestamp signal generated by the vehicle wheel speed sensor, the tire vibration frequency spectrum characteristics related to tire pressure can be obtained after processing such as eliminating sensor tooth ring error, interpolation, and extracting wheel speed signal vibration characteristics; since the vibration spectrum of the corresponding tire will change significantly after the tire pressure decreases, and the change value F of the vibration spectrum characteristics is... va Ratio of actual tire underinflation P re Related;

[0041] (2) The monitoring results of the relative rolling radius module and the vibration spectrum module are comprehensively analyzed by the comprehensive ratio calculation algorithm, and the results of the comprehensive analysis are used for the design of tire pressure alarm strategy and characterization of the actual tire underpressure condition; in the process of characterizing the tire underpressure condition, the tire rolling status and tire underpressure ratio are displayed by the human-machine interaction display module that cooperates with the vehicle tire pressure monitoring system.

[0042] S2, Comprehensive Proportion Calculation Algorithm:

[0043] The formula for calculating the comprehensive ratio is K(ij) = T re (ij)+S com (ij), where i = 0 or 1, 0 represents the front axle and 1 represents the rear axle, j = 0 or 1, 0 represents the left side and 1 represents the right side; the formula for calculating the comprehensive proportional compensation value of the front and rear axles is S. com (ij)=[S com (i)+S com (j)], where, In the above formula, F re (ij) represents the spectral monitoring value of the tire at the corresponding location, F re The formula for calculating (ij) is: ΔF is the normalized value of the change in tire vibration frequency and vibration energy. Because the vibration frequency of a vehicle is not uniform when the tire is underinflated, some models experience significant frequency changes, while others show significant changes in vibration energy at the same frequency. Therefore, the specific value of ΔF depends on the specific vehicle model. drop T represents the inherent characteristic value of the tire vibration spectrum, characterizing the change in the tire's spectral characteristics when the tire is completely underinflated to 0 kPa; re (ij) represents the monitored value of the rolling radius of the tire at the corresponding position, and its calculation formula is: T drop The relative rolling radius is an inherent characteristic value, representing the change in the relative rolling radius of the tire when it is completely underinflated to 0 kPa. ΔT is the amplified value of the relative rolling radius change. The relative rolling radius of a vehicle tire is an inherent characteristic of tire rolling. When the tire is underinflated, its relative rolling speed increases, causing the relative rolling radius to decrease. In actual calculations, considering the influence of factors such as tire slip ratio and rolling resistance on the relative rolling speed, the relative rolling radius change value is used for comprehensive proportional calculation. The relative rolling radius change value ΔT = α * R re R re The physical value representing the change in the tire's relative rolling radius is a relatively small ratio. α is a magnification factor, the value of which is determined by the vehicle type. Since the change in the tire's relative rolling radius caused by tire changes is small, the introduction of α can improve the accuracy of the calculation.

[0044] Furthermore, during actual vehicle use, the relative rolling radius of the tires on the same axle may decrease due to loading. In this case, the tire's spectral characteristics will not change with the loading, making it impossible to determine whether the tire is underinflated. Therefore, a spectral change influence factor F is introduced in this situation. sta As a standard for determining whether a tire is underinflated, F sta The calculation formula is Where m and n are weighting parameters, their values ​​are set according to the vehicle model and are related to factors such as the magnitude of the influence of loading on wheel rolling characteristics. They are used to allocate the spectral influence weights, generally m>n and m+n=1, when S com (i)≥P set And F sta <Q set At that time, it is assumed that K(ij) = F re (ij), and determine that the change in rolling radius is caused by loading, and that no tire underinflation actually occurred, where P set The range is 15-20%, Q set The range is 5-10%, P set and Q setThe value is set according to the vehicle model and is related to factors such as the extent to which the wheel rolling characteristics are affected by the load. It should be noted that the above content only applies to the rear axle tires, because in actual situations, when a vehicle is in motion, it is mainly the rear axle tires that experience a decrease in their relative rolling radius due to external stimuli.

[0045] S3, Single-round rapid alarm compensation:

[0046] When a single wheel experiences rapid underinflation, the indirect tire pressure monitoring system (TPMS) sends an underinflation alarm flag to the PLG system within 2 minutes. Upon receiving the flag signal, the PLG system immediately identifies the situation as a single-wheel rapid underinflation and replaces the overall proportional calculation value with the value calculated by the single-wheel rapid alarm module. At this point, the PLG system needs to input a flag signal. After inputting the flag signal, the system immediately replaces the overall proportional calculation value. At this time, the standard radius calculation value is more accurate, and the relative rolling radius calculation value can be directly used to replace the overall proportional calculation value, i.e., K(ij) = T. re (ij); It should be noted that the above alarm flag is issued by the indirect tire pressure monitoring system. It is the location information corresponding to the rapid alarm issued by the rapid alarm module based on the relative rolling radius when a single tire is underinflated.

[0047] S4. Fitting the actual tire underinflation ratio:

[0048] During tire underinflation, the actual underinflation ratio of the tire is fitted using the comprehensive ratio calculation value K(ij) obtained from the previous steps, based on the actual underinflation ratio of the tire. The fitted tire pressure value P(ij) is P(ij) = K(ij) + ΔK * f(Δk), where K(ij) is the comprehensive ratio calculation value of each tire rolling characteristic, ΔK is the actual tire underinflation ratio, f(Δk) is the correction function, i = 0 or 1, where 0 represents the front axle and 1 represents the rear axle, and j = 0 or 1, where 0 represents the left side and 1 represents the right side. The expression for the correction function is as follows: When the tire underinflation rate is between 0% and 20%, the impact on driving safety, fuel consumption, and tire wear is generally minimal. When the PLG displays the tire underinflation rate in real time, the displayed value needs to be appropriately attenuated to improve system reliability and accuracy. This approach also helps reduce the driver's anxiety caused by the real-time tire underinflation rate display while ensuring driving safety. However, when the actual tire underinflation rate exceeds 40%, driving safety will be severely affected. At this point, the aforementioned correction function needs to be used to appropriately increase the displayed underinflation rate value to reflect the severity of the current underinflation state. In this case, the instrument panel will display an underinflation rate slightly higher than the actual value, indicating that the vehicle is in a dangerous state. The instrument panel will then provide a warning value, prompting the driver to stop the vehicle as soon as possible and take appropriate measures.

[0049] To provide a more intuitive understanding of underinflation, the following guidelines are established based on tire pressure ratios: When the tire pressure ratio is 80-90%, it is considered to be 10-20%, indicating a slightly underinflated tire; when the tire pressure ratio is 60-80%, it is considered to be 20-40%, indicating a moderately underinflated tire; when the actual tire pressure ratio is less than 40%, the tire is considered severely underinflated.

[0050] In practical applications, this invention allows vehicles equipped with PLG-type indirect tire pressure monitoring systems to set PLG operating modes on the vehicle's instrument panel or center console. During use, the driver can select the operating mode as needed, such as choosing a single mode or several modes simultaneously. The specific selection method is not required, as long as it meets the driver's needs. The specific PLG display scheme and operating modes are as follows:

[0051] Mode 0: PLG disabled, no display of tire pressure ratio or tire pressure level; this mode only provides basic indirect tire pressure monitoring alarm function; when a tire is under-pressured, the system only issues an under-pressure warning and indicates the location of the alarm tire; in some embodiments, the monitoring alarm function is implemented by flashing the warning light of the indirect tire pressure monitoring system, while in other embodiments, other methods may be used.

[0052] Mode 1: Delayed display of tire pressure level. The tire pressure level is displayed after a certain period of time following the alarm, and the tire pressure level cannot be changed. In this mode, after a tire pressure alarm is triggered, the system will display the current tire pressure level after a short processing period. This pressure level reflects the tire pressure status at the moment the pressure alarm is issued, and will not be updated as the tire pressure continues to decrease.

[0053] Mode 2: Dynamically displays tire pressure level. Upon alarm activation, the tire pressure level is immediately displayed, indicating three conditions: mild, moderate, and severe underinflation. This level changes based on the analysis of relative rolling radius and vibration spectrum. In this mode, after a tire becomes underinflated and the system issues an alarm, the PLG immediately calculates and displays the tire pressure underinflation ratio and severity. If the tire continues to be underinflated, the PLG will continuously calculate and update the tire pressure underinflation ratio and severity in real time.

[0054] Mode 3: Real-time tire pressure ratio display, showing the tire pressure ratio at any time; in this mode, the system will continuously calculate and display the tire pressure ratio and the degree of tire pressure loss, regardless of whether tire pressure loss occurs.

[0055] In summary, the tire underpressure ratio monitoring method based on an indirect tire pressure monitoring system proposed in this invention is implemented through a PLG system. The PLG system includes a tire rolling characteristic monitoring module, a comprehensive calculation module, and a display module. Based on existing indirect tire pressure monitoring algorithms, it comprehensively calculates the detection results of the tire relative rolling radius model and the tire vibration frequency spectrum model, while simultaneously performing a rapid analysis module for single-wheel underpressure. Finally, it obtains an estimated value of the tire underpressure ratio and uses the display module to display the actual vehicle speed, the underpressure ratio of each tire, and the degree of tire underpressure in real time. The above process can fully leverage the advantages of the indirect tire pressure monitoring system, achieving tire pressure visualization without the need for additional sensors or other equipment, effectively improving driving safety.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for monitoring tire underpressure ratio based on an indirect tire pressure monitoring system, characterized in that, The method is implemented through a PLG system, which includes a tire rolling feature monitoring module, a comprehensive calculation module, and a display module. The tire rolling feature monitoring module is used to realize signal output and processing, relative rolling radius monitoring, tire vibration spectrum monitoring, and single-wheel monitoring under all working conditions. The comprehensive calculation module is used to comprehensively analyze the relative rolling radius characteristics and tire vibration spectrum characteristics, and calculate the estimated value of the tire underinflation ratio accordingly. The display module is used to display the actual vehicle speed, the underinflation ratio of each tire, and the degree of tire underinflation. The PLG system sends the calculation results of the integrated calculation module to the vehicle instrument or central control interface through the vehicle CAN network. The calculation results are based on the existing indirect tire pressure monitoring algorithm, and are obtained by integrating the monitoring results of the tire relative rolling radius model and the tire vibration frequency spectrum model, as well as the data calculation of the single-wheel underpressure rapid analysis module. The method includes the following steps: S1. The indirect tire pressure monitoring system integrated into the vehicle's ABS or ESC continuously collects timestamp signals from wheel speed sensors and vehicle CAN signals, and further calculates and analyzes the relative rolling radius value of the tires based on the collected signals. When the vehicle is driving under conditions that cause a change in the relative rolling radius value of the tires in a non-under-pressure state, or when all four wheels are under-pressured in the same proportion, pattern recognition and calculation are required. S2. Based on the relative rolling radius value of the tire calculated in step S1, and the corresponding tire's spectral monitoring value. and the corresponding tire rolling radius monitoring value Calculate the comprehensive ratio value K. ,in, 0 indicates the front axle, and 1 indicates the rear axle. 0 represents the left side, and 1 represents the right side; This is the combined proportional compensation value for the front and rear axles. ; In step S2, in, This is an inherent characteristic value of the relative rolling radius. These are inherent characteristic values ​​of the tire vibration spectrum. This represents the change in the tire vibration spectrum after underinflation. This is the magnified value of the relative rolling radius change; The relative rolling radius change value ,in, This represents a physical value indicating the change in the relative rolling radius of a tire. As the amplification factor, The value is determined by the vehicle type; S3. After a single wheel experiences rapid underpressure, the indirect tire pressure monitoring system will send an underpressure alarm flag to the PLG system within a preset time. Upon receiving the flag signal, the PLG system immediately identifies the current state as rapid underpressure in a single wheel and replaces the overall proportional calculation value with the value calculated by the single-wheel underpressure rapid analysis module. At this time, the PLG system needs to input the flag signal. .

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