Indirect tire pressure monitoring method and system suitable for complex driving working conditions

Abstract

The present invention provides an indirect tire pressure monitoring method and system suitable for complex driving working conditions, the method comprising: S1, acquiring independent tire speed timestamp signals of the tires of a vehicle, and, on the basis of the tire speed timestamp signals, calculating real-time rolling features of the tires; S2, acquiring a real-time whole-vehicle monitoring signal, identifying, on the basis of a change in a status bit of a specific signal value in the whole-vehicle monitoring signal or a change in the regularity of the signal, current working conditions of the vehicle, and performing, on the basis of the current working conditions, analysis disabling or compensation on the real-time rolling features so as to correct abnormal changes in the rolling features of the tires caused by the current working conditions; and S3, on the basis of the correspondence between the rolling features of the tires and tire pressures and on the basis of the corrected rolling features of the tires, calculating tire pressures. According to the present invention, the accuracy of tire pressure monitoring in complex working conditions is improved, and false alarms or missed reporting by the indirect tire pressure monitoring system are reduced in the actual environment of vehicle use.

Description

An indirect tire pressure monitoring method and system suitable for complex driving conditions Technical Field

[0001] The present invention relates to the field of vehicle monitoring technology, and more particularly, to an indirect tire pressure monitoring method and system suitable for complex driving conditions. Background Art

[0002] At present, the indirect tire pressure monitoring system that relies on monitoring wheel speed must meet the requirements of system stability and reliability while being able to achieve accurate under-pressure alarm.

[0003] Regulations governing tire pressure monitoring systems require that the test road for the system be straight and smooth, the vehicle travel smoothly during testing, and the vehicle load remain constant. However, actual vehicle use inevitably fails to meet these ideal conditions. Due to the complexities of the vehicle environment and unique driving conditions, indirect tire pressure monitoring systems face a significant risk of missed and false alarms. Therefore, the ability to identify and handle unique driving conditions significantly impacts the performance ceiling of indirect tire pressure monitoring systems.

[0004] By performing a series of processing on the vehicle's basic wheel speed signal, we can derive the basic rolling characteristics of the tires, including the relative rolling radius characteristic Ri between each tire and the vibration frequency characteristic Fi of each tire during rolling. These two tire rolling characteristics are highly correlated with tire pressure. For example, if the relative rolling radius of a tire decreases relative to the other tires and the tire's vibration frequency characteristic changes significantly, it indicates that the tire is under-inflated.

[0005] In actual vehicle practice, it was found that vehicle driving conditions and driving behavior have a significant impact on tire rolling characteristics. If the tire pressure monitoring system does not make special arrangements for some unconventional conditions, it will seriously affect the performance of the indirect tire pressure monitoring system, causing the indirect tire pressure monitoring system to frequently report false alarms or missed alarms in the actual vehicle environment.

[0006] Therefore, it is necessary to study a tire pressure monitoring system that is associated with the real-time working conditions of the vehicle to achieve more accurate tire pressure monitoring.

[0007] Summary of the Invention

[0008] The present invention addresses the technical problems existing in the prior art and provides an indirect tire pressure monitoring method and system suitable for complex driving conditions, so as to solve the problem that different driving conditions restrict the accuracy of tire pressure monitoring results.

[0009] According to a first aspect of the present invention, there is provided an indirect tire pressure monitoring method applicable to complex driving conditions, comprising:

[0010] S1, obtaining independent wheel speed time stamp signals of each tire of the vehicle, and calculating the real-time rolling characteristics of each tire according to the wheel speed time stamp signals;

[0011] S2, obtaining a real-time vehicle monitoring signal, identifying the current operating condition of the vehicle based on changes in the status bits of specific signal values ​​or regular changes in the signal in the vehicle monitoring signal, and analyzing, disabling, or compensating for the real-time rolling characteristics based on the current operating condition to correct abnormal changes in the tire rolling characteristics caused by the current operating condition;

[0012] S3, based on the corresponding relationship between the tire rolling characteristics and the tire pressure, calculating the tire pressure according to the corrected tire rolling characteristics.

[0013] On the basis of the above technical solution, the present invention can also make the following improvements.

[0014] Optionally, in step S1, the real-time rolling feature includes a vibration frequency domain feature Fi and a relative rolling radius feature Ri.

[0015] Optionally, step S2 includes:

[0016] Obtain a real-time brake flag signal from the vehicle monitoring signal, and obtain the time t0 when the brake is applied and the time t1 when the brake is released according to the state change of the brake flag signal; obtain the rolling angular velocity change value Δω corresponding to each tire from the wheel speed timestamp signal of each tire FL , Δω FR , Δω RL and Δω RR , and obtain the moment t2 when the tire rolling angular velocity is zero, and calculate the vehicle's braking degree B by the following formula: ω=1 / 4(Δω FL +Δω FR +Δω RL +Δω RR ) (2), B=ω / Δt (3),

[0017] Wherein, Δt is the actual braking time, ω is the change in the rolling angular velocity of the tire;

[0018] The calculated braking degree B is compared with a preset vehicle braking identification parameter B0, which is set based on the actual vehicle calibration result:

[0019] If B≤B0, the vehicle's current operating condition is determined to be normal braking, and there is no need to correct the tire rolling characteristics;

[0020] If B>B0, the current operating condition of the vehicle is determined to be emergency braking, and the relative rolling radius characteristic Ri of the tire is analyzed and disabled to stop the calculation and update of the relative rolling radius characteristic Ri until it is determined that the emergency braking is released.

[0021] Optionally, step S2 includes:

[0022] The real-time lateral acceleration L and yaw rate Y are obtained based on the vehicle monitoring signal, and the discrete degree of lateral acceleration D(L) and the discrete degree of yaw rate D(Y) within k sampling periods are calculated respectively:

[0023] Where Li is the lateral acceleration data collected in the i-th cycle, i∈[1,k], Yj is the yaw rate data collected in the i-th cycle, j∈[1,k], k is a natural number;

[0024] The real-time turning condition weighted value W(h) is calculated based on the discrete degree of lateral acceleration D(L) and the discrete degree of yaw rate D(Y):

[0025] Among them, m and n are weighted parameters, which are set according to the vehicle model parameters and the actual vehicle turning characteristics;

[0026] Compare the turning condition weighted value W(h) with the weight threshold W0 to determine whether the vehicle is currently in a turning condition:

[0027] If W(h) < W0, it is determined that the current condition is not a turning condition and there is no need to correct the tire rolling characteristics;

[0028] If W(h)>2W0, it is determined that the current working condition is a combination of cornering and loading. The tire's relative rolling radius characteristic Ri and vibration frequency domain characteristic Fi are analyzed and disabled to stop the calculation and update of the tire's real-time rolling characteristics until the current working condition is determined to be over.

[0029] If W0≤W(h)≤2W0, it is determined that the current state is in a turning state, and the real-time yaw rate information Y(t) is calculated by the following formula (7): Y(t)=±[(R FL +R RL ) / 2-(R FR +R RR ) / 2] / A (7),

[0030] Among them, A is the vehicle wheel spacing parameter, R FL 、R RL 、R FR and R RR are the relative rolling radius values ​​of each wheel of the vehicle;

[0031] The wheel speed difference ΔR between the two sides of the vehicle is calculated by the following formula (8): ΔR=±AY(t) (8),

[0032] Among them, the positive or negative value of ΔR is related to the turning direction;

[0033] The wheel speed difference ΔR of the tires on both sides of the vehicle is compensated to the relative rolling radius characteristic Ri of the tire on the side where the rolling radius decreases abnormally.

[0034] Optionally, step S2 includes:

[0035] Select the two frequencies with the highest degree of influence on the road surface excitation, and extract the frequency domain eigenvalues ​​corresponding to the two frequencies from the vibration frequency domain characteristics Fi of each tire of the vehicle to obtain the first frequency domain eigenvalue and the second frequency domain eigenvalue;

[0036] Based on the changes in the amplitude of the first frequency domain eigenvalue and the amplitude of the second frequency domain eigenvalue over time, combined with the changes in the tire relative rolling radius characteristic Ri over time, it is determined whether each tire is currently in a non-uniformly proportioned under-inflated state or a uniformly proportioned under-inflated state:

[0037] If it is determined to be in a non-uniform underpressure or uniform underpressure state, rough road recognition will be stopped;

[0038] If it is determined that the vehicle is not in a non-proportional undervoltage state or a proportional undervoltage state, the first frequency domain characteristic value and the second frequency domain characteristic value are averaged respectively to obtain the first frequency vibration characteristic compensation value Power1 and the second frequency vibration characteristic compensation value Power2 reflecting the road roughness, and the first frequency vibration characteristic compensation value Power1 and the second frequency vibration characteristic compensation value Power2 are compensated to the vibration frequency domain characteristics Fi of each tire of the vehicle.

[0039] Optionally, judging whether each tire is currently in a non-uniformly proportional under-pressure state or an identically proportional under-pressure state based on changes in the amplitude of the first frequency domain eigenvalue and the amplitude of the second frequency domain eigenvalue over time in combination with changes in the tire relative rolling radius characteristic Ri over time includes:

[0040] If the amplitude of the first frequency domain eigenvalue, the amplitude of the second frequency domain eigenvalue, and the tire relative rolling radius characteristic Ri change synchronously over time, it is determined that the four wheels are currently in a non-uniformly proportional under-pressure state;

[0041] If the tire relative rolling radius characteristic Ri changes little in a certain period of time, and the amplitude of the first frequency domain characteristic value and the amplitude of the second frequency domain characteristic value change in the same pattern over time, it is determined that the four wheels are currently in a state of proportional underpressure.

[0042] Optionally, step S2 includes:

[0043] Obtain the longitudinal acceleration signal Xt based on the time domain from the vehicle monitoring signal, and obtain the smoothed and reliable longitudinal acceleration filtered signal value St after filtering through Equation (9): S t = αXt + (1 - α)S t-1 (9),

[0044] where α is the filtering parameter, and S t-1 is the longitudinal acceleration filtered signal value at the previous moment;

[0045] Obtain the wheel speed of the vehicle's driven wheels based on the wheel speed timestamp signal of the wheels, and calculate the actual acceleration Area of the vehicle based on the change rate of the wheel speed of the vehicle's driven wheels within a unit time;

[0046] Calculate the average value Vi of the wheel speeds of the two driven wheels and the average value Vo of the wheel speeds of the two driving wheels according to the wheel speed timestamp signals of the four wheels, and calculate the driving slip ratio H according to the average value Vi of the wheel speeds of the two driven wheels and the average value Vo of the wheel speeds of the two driving wheels:

[0047] Judge whether the vehicle is currently in an uphill / downhill working condition according to the longitudinal acceleration filtered signal value St, the actual acceleration Area of the vehicle, and the driving slip ratio H:

[0048] If St > H / H0Area, it is determined that the vehicle is in an uphill / downhill working condition; where H0 is the slip ratio threshold;

[0049] When in an uphill / downhill working condition, if H < H0, there is no need to correct the tire rolling characteristics.

[0050] Optionally, step S2 includes:

[0051] Obtain the torque fluctuation signal T(h) based on the time domain from the vehicle monitoring signal, and calculate the dynamic driving degree Tva of the vehicle in combination with the torque value T during uniform driving: T va = T(h) / T (1'')

[0052] Judge whether the vehicle is in a dynamic driving working condition according to the dynamic driving degree Tva and the driving slip ratio H:

[0053] If H ≥ H0 and Tva > T C , it is determined that the vehicle is in a dynamic driving working condition, where T C is the dynamic driving threshold, and the value of T C is set according to experience;

[0054] For the dynamic driving working condition, calculate the gain for the relative rolling radius of the driving wheels through the following Equation (12): R = R 驱动*f(H) (12),

[0055] Where f(H) is the gain function related to the current driving slip ratio, R 驱动 is the relative rolling radius of the driving wheel, R is the relative rolling radius of the driving wheel after the gain is calculated;

[0056] The gained driving wheel relative rolling radius R is updated to the relative rolling radius feature Ri.

[0057] Optionally, step S2 further includes:

[0058] If it is determined that there is a current loading change according to the longitudinal acceleration filtered signal value St, and it is determined that the vehicle is not currently in a braking condition, an uphill or downhill condition, or a dynamic driving condition, then it is determined that the vehicle is currently in a loading condition;

[0059] Obtain the longitudinal acceleration change S corresponding to different vehicle loads M recorded during the actual vehicle calibration phase T负载 , Longitudinal acceleration change S when no load T空载 and the relative rolling radius change ΔR of the coaxial tire load , when the load M is within the vehicle load range, the following relationship exists: ΔR load =p(S T负载 -S T空载 ) (13),

[0060] Where p is the proportionality coefficient;

[0061] The longitudinal acceleration change S corresponding to the vehicle's current load T负载 Substitute into formula (13) to calculate the relative rolling radius change ΔR of the coaxial tire corresponding to the current load load ;

[0062] The calculated relative rolling radius change of the coaxial tire ΔR load Compensation is made for the abnormal changes in the relative rolling radius characteristic Ri of the tire caused by loading conditions.

[0063] According to a second aspect of the present invention, there is provided an indirect tire pressure monitoring system suitable for complex driving conditions, comprising:

[0064] a decomposition module, configured to obtain independent wheel speed time stamp signals of each tire of the vehicle, and calculate the real-time rolling characteristics of each tire based on the wheel speed time stamp signals;

[0065] a correction module for acquiring real-time vehicle monitoring signals, identifying the vehicle's current operating condition based on changes in status bits of specific signal values ​​or regular changes in the signals, and analyzing, disabling, or compensating for the real-time rolling characteristics based on the current operating condition to correct abnormal changes in the tire rolling characteristics caused by the current operating condition;

[0066] The solution module is used to calculate the tire pressure according to the corrected tire rolling characteristics based on the corresponding relationship between the tire rolling characteristics and the tire pressure.

[0067] According to a third aspect of the present invention, an electronic device is provided, comprising a memory and a processor, wherein the processor is configured to implement the steps of the above-mentioned indirect tire pressure monitoring method applicable to complex driving conditions when executing a computer management program stored in the memory.

[0068] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, on which a computer management program is stored. When the computer management program is executed by a processor, the steps of the above-mentioned indirect tire pressure monitoring method applicable to complex driving conditions are implemented.

[0069] The present invention provides an indirect tire pressure monitoring method, system, electronic device and storage medium suitable for complex driving conditions. The method identifies the current operating status of the vehicle based on the real-time monitoring signal of the vehicle, and focuses on identifying and processing special conditions in the actual vehicle use environment, especially driving conditions that may affect the rolling characteristics of the tire, such as braking and braking, mountain roads (uphill and downhill and turning), load change conditions, dynamic driving, rough roads, etc., and processes the tire rolling characteristics according to different driving conditions by means of analysis, disabling or compensation, and corrects the abnormal changes in the tire rolling characteristics caused by special driving conditions, so that the changes in the tire relative rolling radius characteristics and the changes in the vibration spectrum characteristics are only strongly correlated with the tire pressure changes, eliminating the connection between the tire rolling characteristics and unconventional driving conditions, and improving the accuracy of indirect tire pressure monitoring in the actual vehicle use environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG1 is a flow chart of an indirect tire pressure monitoring method applicable to complex driving conditions provided by the present invention;

[0071] FIG2 is a block diagram of an indirect tire pressure monitoring system suitable for complex driving conditions provided by the present invention;

[0072] FIG3 is a schematic diagram of the hardware structure of a possible electronic device provided by the present invention;

[0073] FIG4 is a schematic diagram of the hardware structure of a possible computer-readable storage medium provided by the present invention. DETAILED DESCRIPTION

[0074] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0075] FIG1 is a flow chart of an indirect tire pressure monitoring method applicable to complex driving conditions provided by the present invention. As shown in FIG1 , the method includes steps S1 to S3:

[0076] S1, obtaining independent wheel speed time stamp signals of each tire of the vehicle, and calculating the real-time rolling characteristics of each tire according to the wheel speed time stamp signals;

[0077] S2, obtaining a real-time vehicle monitoring signal, identifying the current operating condition of the vehicle based on changes in the status bits of specific signal values ​​or regular changes in the signal in the vehicle monitoring signal, and analyzing, disabling, or compensating for the real-time rolling characteristics based on the current operating condition to correct abnormal changes in the tire rolling characteristics caused by the current operating condition;

[0078] S3, based on the corresponding relationship between the tire rolling characteristics and the tire pressure, calculating the tire pressure according to the corrected tire rolling characteristics.

[0079] It is understandable that, based on the defects in the background technology, the embodiment of the present invention proposes an indirect tire pressure monitoring method suitable for complex driving conditions. The present invention identifies the current operating status of the vehicle based on the real-time monitoring signal of the vehicle, and especially focuses on identifying and processing special conditions in the actual vehicle use environment, especially driving conditions that may affect the rolling characteristics of the tire, such as braking and braking, mountain roads (uphill and downhill and turning), load change conditions, dynamic driving, rough roads, etc., and processes the tire rolling characteristics according to different driving conditions by means of partial analysis disabling, full analysis disabling or compensation, and corrects the abnormal changes in the tire rolling characteristics caused by special driving conditions, so that the changes in the tire relative rolling radius characteristics and the changes in the vibration spectrum characteristics are only strongly correlated with the tire pressure changes, eliminating the connection between the tire rolling characteristics and unconventional driving conditions, and improving the accuracy of indirect tire pressure monitoring in the actual vehicle use environment.

[0080] In step S1 of this embodiment, the real-time rolling characteristics of each tire are calculated based on the collected independent wheel speed time stamp signals of each tire of the vehicle. The real-time rolling characteristics include the vibration frequency domain characteristics Fi and the relative rolling radius characteristics Ri (for example, the relative rolling radius characteristics R corresponding to the four tires mentioned later). FL 、R RL 、R FR and R RR ).

[0081] It can be understood that the tire rolling characteristics mentioned in the present invention include the independent vibration spectrum information of the vehicle's four tires and the relative wheel speed difference (i.e., relative rolling radius) of a tire relative to the other three tires. Under ideal conditions, the rolling characteristics of a tire and the tire pressure can be expressed as (Pi, Ri, Fi) respectively. Pi, Ri, and Fi are correlated, and the value of the third one can be inferred from the values ​​of two of them.

[0082] More specifically, Pi is the actual tire pressure value at a certain moment under ideal conditions (since temperature factors directly cause changes in tire pressure in a closed and independent tire system, such changes can also reflect changes in tire rolling characteristics).

[0083] Ri is the relative rolling radius of the tire when the actual pressure is Pi, approximated using the tire's rotational angular velocity. Extracting the relative rolling radius feature Ri from the wheel speed timestamp signal is a prior art method. For details on extracting this feature, see patent ZL 202111004413.3.

[0084] Fi is the tire's vibration frequency domain characteristic value when the actual tire pressure is Pi. Fi reflects changes in the vibration characteristics caused by tire deformation. The method for extracting the wheel vibration frequency domain characteristic Fi from the wheel speed timestamp signal is prior art. For details on extracting this characteristic, please refer to patent "ZL 201910226001.0."

[0085] Under ideal conditions, the above two types of tire rolling characteristics can be used to monitor the air pressure status of the tire, but the problem is that these two types of tire rolling characteristics may be affected by special operating conditions during vehicle driving. Under ideal conditions, when the actual pressure Pi of a certain tire changes, especially when the actual tire pressure becomes smaller, the rolling radius value of this tire will become smaller relative to other tires, which is reflected in the change of the relative rolling radius value Ri of this tire; similarly, the vibration frequency domain characteristics Fi will also change relative to the vibration characteristics of this tire when the pressure was normal at a certain moment before. Therefore, the purpose of the present invention is to identify various operating conditions that will affect the tire rolling characteristics during the actual driving process of the vehicle based on the input signal of the whole vehicle, and to eliminate / correct the influence of these operating conditions on the tire rolling characteristics through calculation, so as to monitor the tire pressure changes through the corrected tire rolling characteristics and obtain accurate tire pressure monitoring results.

[0086] It should be noted that the vehicle monitoring signal mainly refers to the signal input by the system to the whole vehicle, such as: 1. The independent wheel speed timestamp signal of the four wheels; 2. The original CAN signal of the whole vehicle: the actual engine / motor output torque signal, the actual engine / motor speed signal, the brake flag signal, the acceleration sensor signal (lateral acceleration, longitudinal acceleration, yaw rate signal). By comprehensively calculating the above vehicle monitoring signals, the real-time rolling characteristics of the tire under ideal conditions can be obtained.

[0087] The above-mentioned vehicle monitoring signals can also be used to monitor and identify the vehicle's current operating status (driving conditions). The system identifies the vehicle's current operating status based on changes in the status bit of a specific input signal value or a regular pattern of changes in multiple signals. After identifying different operating conditions, the system further determines and corrects abnormal changes in tire rolling characteristics caused by special driving conditions through methods such as partial disabling and comprehensive compensation, thereby monitoring tire pressure changes.

[0088] In one possible embodiment, step S2, the process of identifying and processing the braking condition, includes:

[0089] Obtain a real-time brake flag signal from the vehicle monitoring signal, and obtain the time t0 of braking and the time t1 of brake release according to the state change of the brake flag signal; obtain the rolling angular velocity change value Δω corresponding to each of the four tires from the wheel speed timestamp signal of the four tires FL , Δω FR , Δω RL and Δω RR , and obtain the moment t2 when the tire rolling angular velocity is zero, and calculate the vehicle braking degree B by the following formula (1): ω=1 / 4(Δω FL +Δω FR +Δω RL +Δω RR ) (2), B=ω / Δt (3),

[0090] Wherein, Δt is the actual braking time, ω is the change in the rolling angular velocity of the tire;

[0091] The calculated braking degree B is compared with a preset vehicle braking identification parameter B0, which is set based on the actual vehicle calibration results. B0 is related to the vehicle's braking system performance and vehicle mass:

[0092] If B≤B0, the vehicle's current operating condition is determined to be normal braking, and there is no need to correct the tire rolling characteristics;

[0093] If B>B0, the vehicle's current operating condition is determined to be emergency braking. The emergency braking action significantly affects the tire rolling radius characteristic Ri, and the change in Ri has no clear correlation with the braking behavior and the braking force. Therefore, the tire's relative rolling radius characteristic Ri is analyzed and disabled to stop the calculation and update of the relative rolling radius characteristic Ri until it is determined that the emergency braking is released.

[0094] It can be understood that this embodiment determines the degree of influence of the current braking action. The braking action of the vehicle will directly affect the wheel speed of each tire and thus affect the analysis of the tire relative rolling radius characteristic Ri. This system identifies the braking type (distinguishing between emergency braking and conventional braking) according to the degree of braking while the vehicle is driving, and handles different braking types differently. When the vehicle brake pedal is lightly depressed and generates a weak braking force, the brake flag of the entire vehicle will respond and input a braking command to the system. After braking occurs, the tire angular velocity change rate is calculated, and the braking degree is further calculated based on the various time nodes monitored, and then the tire rolling radius characteristic Ri is processed accordingly according to the braking degree.

[0095] It should be noted that analysis disablement in this invention means that upon identifying a triggering condition for analysis disablement at a certain moment, the calculation and updating of the relevant tire rolling characteristics will be immediately stopped until the relevant tire rolling characteristics no longer trigger the disablement condition in a subsequent cycle. After the disablement condition is no longer met, analysis and calculation of the tire rolling characteristics will continue based on the vehicle input signal (vehicle monitoring signal) in the current cycle.

[0096] In a possible embodiment, in step S2, the process of identifying and processing a mountain road condition (turning condition) includes:

[0097] The real-time lateral acceleration L, longitudinal acceleration X, and yaw rate Y are acquired from the attitude acceleration sensor signals in the vehicle monitoring signal. Lateral acceleration L and yaw rate Y can be used to identify cornering conditions on mountain roads, while longitudinal acceleration X can be used to identify uphill and downhill conditions on mountain roads. The system preferably collects sample points for each of the three signals at a sampling frequency of 100ms.

[0098] Regarding the identification of the turning condition, first calculate the discrete degree of lateral acceleration D(L) and the discrete degree of yaw rate D(Y) within k sampling periods:

[0099] Where Li is the lateral acceleration data collected in the i-th cycle, i∈[1,k], Yj is the yaw rate data collected in the i-th cycle, j∈[1,k], k is a natural number, and the value of k is preferably 10;

[0100] The lateral acceleration D and the yaw rate Y are used together to identify the turning condition. The discrete degree of the lateral acceleration D(L) and the discrete degree of the yaw rate D(Y) are weighted according to their physical characteristics to calculate the real-time turning condition weighted value W(h):

[0101] Among them, m and n are weighted parameters, which are set according to the vehicle model parameters and the actual vehicle turning characteristics;

[0102] W(h) is used to determine whether the vehicle is in a turning state. Considering whether the computing resources and monitoring frequency are sufficient to identify all turning conditions, it is assumed that the W(h) value is the vehicle turning signal characteristic value within the current 10 seconds. The system performs a calculation every 10 seconds, continuously updating the W value as time h changes. W(h) is dynamically compared with the preset parameter W0 over time to determine the vehicle turning condition. The specific operation is as follows:

[0103] The turning condition weighted value W(h) is dynamically compared with the weight threshold W0 in a 1s cycle to determine whether the vehicle is currently in a turning condition:

[0104] If W(h) < W0, it is determined that the current condition is not a turning condition and there is no need to correct the tire rolling characteristics;

[0105] If W(h)>2W0, it is assumed that the change in the tire's relative rolling radius is not only caused by vehicle turning, but also by tire deformation caused by changes in tire load. Therefore, it is determined that the current working condition is a combination of turning and loading. The tire's relative rolling radius characteristic Ri and vibration frequency domain characteristic Fi are analyzed and disabled to stop the calculation and update of all real-time tire rolling characteristics until the current working condition is determined to have ended.

[0106] If W0≤W(h)≤2W0, it is determined that the current working condition is turning. In this case, the wheel speed difference that causes the change in the relative rolling radius of the tire is considered to be caused only by turning. The real-time yaw rate information Y(t) is calculated by the following formula (7): Y(t)=±[(R FL +R RL ) / 2-(R FR +R RR ) / 2] / A (7),

[0107] Among them, A is the vehicle wheel spacing parameter, R FL 、R RL 、R FR and R RR are the relative rolling radius values ​​of each wheel of the vehicle, more specifically, R FL is the relative rolling radius of the left front wheel relative to the other three wheels, R RL is the relative rolling radius of the left rear wheel relative to the other three wheels, R FRis the relative rolling radius of the right front wheel relative to the other three wheels, R RR is the relative rolling radius of the right rear wheel relative to the other three wheels;

[0108] The wheel speed difference ΔR between the two sides of the vehicle is calculated by the following formula (8): ΔR=±AY(t) (8),

[0109] Among them, the positive or negative value of ΔR is related to the turning direction;

[0110] The wheel speed difference ΔR of the tires on both sides of the vehicle is compensated to the relative rolling radius characteristic Ri of the tire on the side where the rolling radius decreases abnormally.

[0111] In one possible embodiment, in step S2, the identification and processing of the rough road condition includes:

[0112] Select the two frequencies with the highest degree of influence on the road surface excitation, and extract the frequency domain eigenvalues ​​corresponding to the two frequencies from the vibration frequency domain characteristics Fi of each tire of the vehicle to obtain the first frequency domain eigenvalue and the second frequency domain eigenvalue;

[0113] Based on the changes in the amplitude of the first frequency domain eigenvalue and the amplitude of the second frequency domain eigenvalue over time, combined with the changes in the tire relative rolling radius characteristic Ri over time, it is determined whether each tire is currently in a non-uniformly proportioned under-inflated state or a uniformly proportioned under-inflated state:

[0114] If the amplitude of the first frequency domain eigenvalue, the amplitude of the second frequency domain eigenvalue, and the tire relative rolling radius characteristic Ri change synchronously over time, it is determined that the four wheels are currently in a non-uniformly proportional under-pressure state;

[0115] If the tire relative rolling radius characteristic Ri changes little over a certain period of time, and the amplitudes of the first frequency domain characteristic value and the second frequency domain characteristic value change in the same pattern over time, it is determined that the four wheels are currently in a state of proportional underpressure;

[0116] If it is determined to be in a non-uniform underpressure or uniform underpressure state, rough road recognition will be stopped;

[0117] If it is determined that the vehicle is not in a non-proportional undervoltage state or a proportional undervoltage state, the first frequency domain characteristic value and the second frequency domain characteristic value are averaged respectively to obtain the first frequency vibration characteristic compensation value Power1 and the second frequency vibration characteristic compensation value Power2 reflecting the road roughness, and the first frequency vibration characteristic compensation value Power1 and the second frequency vibration characteristic compensation value Power2 are compensated to the vibration frequency domain characteristics Fi of each tire of the vehicle.

[0118] It can be understood that, under the premise that the vehicle suspension and tire properties are determined, the tire rolling vibration frequency domain spectrum is only affected by tire pressure and road excitation. The road excitation of the wheel will generally affect the spectrum around 25Hz and around 60Hz, and the higher the road surface roughness, the greater the spectrum noise characteristics. Therefore, in this embodiment, the first frequency is selected as 25Hz and the second frequency is selected as 60Hz. In this embodiment, the frequency domain characteristic values ​​corresponding to the 25Hz and 60Hz frequencies of each tire are monitored. Generally, there are numerical and temporal differences in the frequency domain characteristic amplitude changes corresponding to the 25Hz and 60Hz frequencies of each tire caused by the rough road surface. Here, when judging the rough road surface based on the frequency domain characteristic amplitude changes corresponding to the 25Hz and 60Hz frequencies, two situations need to be eliminated: four wheels with different proportions of underpressure and four wheels with the same proportion of underpressure. The reasons are:

[0119] When four wheels are under-inflated at different ratios, the tire relative rolling radius characteristics will change accordingly. Changes in the frequency domain eigenvalues ​​at 25Hz and 60Hz may be caused by tire under-inflatement.

[0120] When four wheels are under-inflated at the same rate, the tire relative rolling radius characteristics do not change. However, if the frequency domain eigenvalues ​​corresponding to 25Hz and 60Hz of the four tires change in the same manner within the same sampling period, this change is considered to be caused by the same rate of under-inflation on all four wheels.

[0121] If either of the two tire underpressure conditions is detected, rough road condition recognition ceases. After eliminating these two conditions, the Power1 and Power2 values, reflecting the current road roughness, are calculated by taking the average of the frequency domain eigenvalues ​​corresponding to the four wheels at 25Hz and 60Hz, respectively. These calculated Power1 and Power2 values ​​can be directly used to compensate for abnormal variations in tire vibration characteristics by adding them to the vibration frequency domain characteristics Fi for each tire.

[0122] Dynamic driving, load changes, and uphill and downhill road recognition are all related to the vehicle's longitudinal acceleration. The vehicle's longitudinal acceleration signal monitors changes in vertical acceleration and is used to determine changes in the vehicle's pitch angle. Changes in the longitudinal acceleration signal are primarily caused by changes in the vehicle's driving slope, combined with changes in acceleration and deceleration, and load. Combined with changes in other vehicle operating characteristics and tire rolling characteristics, it can be used to distinguish between dynamic driving conditions, load changes, and uphill and downhill conditions.

[0123] In a possible embodiment, in step S2, identifying and processing uphill and downhill conditions includes:

[0124] Based on the vehicle's monitoring signals, obtain the longitudinal acceleration signal Xt in the time domain, and after filtering through Equation (9), obtain the smoothed and reliable longitudinal acceleration filtered value St: S t = αXt + (1 - α)S t-1 (9),

[0125] where α is the filtering parameter, and S t-1 is the longitudinal acceleration filtered value at the previous moment;

[0126] Based on the wheel speed timestamp signal of the wheel, obtain the wheel speed of the vehicle's driven wheel. The driven wheel is a freely rolling wheel without driving force. Based on the physical radius of the tire, the rolling linear speed can be obtained. Based on the change rate of the vehicle's driven wheel speed within a unit time, obtain the actual acceleration Area of the vehicle. The calculation frequency of this actual acceleration Area is consistent with the update frequency of the longitudinal acceleration signal Xt input by the vehicle attitude sensor;

[0127] Due to the existence of the driving wheel end torque, the driving wheel must have dynamic friction with the road surface and generate relative slip. The driven wheels of a two-wheel drive vehicle do not have this relative slip; when the vehicle is in a normal driving state, based on the wheel speed timestamp signals of the four wheels, calculate the average value Vi of the wheel speeds of the two driven wheels and the average value Vo of the wheel speeds of the two driving wheels, and calculate the drive slip ratio H based on the average value Vi of the wheel speeds of the two driven wheels and the average value Vo of the wheel speeds of the two driving wheels:

[0128] Based on the longitudinal acceleration filtered value St, the actual acceleration Area of the vehicle, and the drive slip ratio H, determine whether the vehicle is currently in an uphill or downhill working condition:

[0129] If St > H / H0Area, it is determined that the vehicle is in an uphill or downhill working condition; where H0 is the slip ratio threshold;

[0130] When in an uphill or downhill working condition, since the influence of a simple slope change on the tire rolling characteristics is relatively small, if the slip ratio H < H0, there is no need to correct the tire rolling characteristics.

[0131] In a possible implementation manner, in step S2, the dynamic driving conditions are identified and processed, including:

[0132] Based on the vehicle's monitoring signals, obtain the torque fluctuation signal T(h) in the time domain, and combine it with the torque value T during uniform driving to calculate the vehicle's dynamic driving degree Tva: T va = T(h) / T (11),

[0133] In this embodiment, the vehicle driving torque is called at a frequency of 1s / time, and the torque fluctuation within 10 sampling periods (a total of 10s) is calculated and represented by T(h). The degree of torque dispersion is dynamically determined over time, and the ratio of the T(h) value within each 10s to the T value (preset parameter) during uniform speed driving (here, uniform speed driving means that the speed fluctuation range does not exceed 1%) is monitored at all times to determine the vehicle's dynamic driving level.

[0134] Determine whether the vehicle is in a dynamic driving condition based on the dynamic driving degree Tva and the driving slip ratio H:

[0135] If H≥H0 continues to appear within the preset calculation cycle (for example, 10 calculation cycles), and Tva>T C , then it is determined that the vehicle is in a dynamic driving condition, where T C is the dynamic driving threshold, T C The value of is set according to experience, for example, the preferred value is 1.5;

[0136] For dynamic driving conditions, the gain of the relative rolling radius of the driving wheel is calculated by the following formula (12): R = R 驱动 *f(H) (12),

[0137] Where f(H) is the gain function related to the current driving slip ratio, R 驱动 is the relative rolling radius of the driving wheel, R is the relative rolling radius of the driving wheel after the gain is calculated;

[0138] The gained driving wheel relative rolling radius R is updated to the relative rolling radius feature Ri.

[0139] It is understandable that dynamic driving behavior causes the drive wheels to rotate too quickly, and accordingly, their rolling radius is reduced relative to the actual radius. Therefore, it is necessary to make appropriate corrections to this abnormal change.

[0140] In one possible embodiment, step S2, identifying and processing the loading condition, includes:

[0141] If it is determined that the vehicle is not currently in a braking condition, an uphill or downhill condition, or a dynamic driving condition, and it is determined based on the longitudinal acceleration filter signal value St that a loading change is currently present, then it is determined that the vehicle is currently in a loading condition;

[0142] Obtain the longitudinal acceleration change S corresponding to different vehicle loads M recorded during the actual vehicle calibration phase T负载 , Longitudinal acceleration change S when no load T空载 and the relative rolling radius change ΔR of the coaxial tire load , when the load M is within the vehicle load range, the following relationship exists: ΔRload =p(S T负载 -S T空载 ) (13),

[0143] Where p is the proportionality coefficient;

[0144] The longitudinal acceleration change S corresponding to the vehicle's current load T负载 Substitute into formula (13) to calculate the relative rolling radius change ΔR of the coaxial tire corresponding to the current load load ;

[0145] The calculated relative rolling radius change of the coaxial tire ΔR load Compensation is made for the abnormal changes in the relative rolling radius characteristic Ri of the tire caused by loading conditions.

[0146] It's understandable that varying vehicle loads will cause varying degrees of static longitudinal acceleration. This variation originates from all of the vehicle's elastic support structures. Loading can reduce the tire radius and cause deformation of the suspension structure. Changes in longitudinal acceleration can be measured in real time by attitude sensors, while changes in tire rolling radius can be calculated from wheel speed time-stamp signals. Some active suspension systems can input suspension deformation information, which can be used directly to determine whether a load change has occurred.

[0147] Changes in the longitudinal acceleration filter signal value St can be caused by braking, dynamic driving, uphill and downhill conditions, and loading. Therefore, in the specific implementation, after eliminating braking, braking, uphill and downhill conditions, and dynamic driving conditions according to the aforementioned embodiment, the change in the longitudinal acceleration filter signal value St is only linearly correlated with changes in loading. The relative rolling radius of the tire will also change due to loading, so this embodiment compensates for this change.

[0148] When there is a load change and the influence of braking, dynamic driving, uphill and downhill, and dynamic driving is excluded, the load change and the longitudinal acceleration filter signal value S t The change of is positively correlated with the change of the relative rolling radius of the coaxial tire (the load change generally acts on the coaxial tire). Therefore, during the actual vehicle calibration phase of the tire pressure monitoring system, the aforementioned relationship (13) was obtained through several experiments. During the actual driving process, the longitudinal acceleration change S corresponding to the real-time load monitored is T负载 Substituting into formula (13), the relative rolling radius change ΔR of the coaxial tire corresponding to the current load can be calculated: load ; , the calculated compensation is added to the relative rolling radius characteristic Ri of a certain axle wheel affected by the loading condition, which can eliminate the influence of the loading condition on tire pressure monitoring.

[0149] FIG2 is a structural diagram of an indirect tire pressure monitoring system suitable for complex driving conditions provided by an embodiment of the present invention. As shown in FIG2 , an indirect tire pressure monitoring system suitable for complex driving conditions includes a decomposition module, a correction module, and a solution module, wherein:

[0150] a decomposition module, configured to obtain independent wheel speed time stamp signals of each tire of the vehicle, and calculate the real-time rolling characteristics of each tire based on the wheel speed time stamp signals;

[0151] a correction module for acquiring real-time vehicle monitoring signals, identifying the vehicle's current operating condition based on changes in status bits of specific signal values ​​or regular changes in the signals, and analyzing, disabling, or compensating for the real-time rolling characteristics based on the current operating condition to correct abnormal changes in the tire rolling characteristics caused by the current operating condition;

[0152] The solution module is used to calculate the tire pressure according to the corrected tire rolling characteristics based on the corresponding relationship between the tire rolling characteristics and the tire pressure.

[0153] It can be understood that the indirect tire pressure monitoring system suitable for complex driving conditions provided by the present invention corresponds to the indirect tire pressure monitoring method suitable for complex driving conditions provided by the aforementioned embodiments. The relevant technical features of the indirect tire pressure monitoring system suitable for complex driving conditions can refer to the relevant technical features of the indirect tire pressure monitoring method suitable for complex driving conditions, which will not be repeated here.

[0154] Please refer to Figure 3, which is a schematic diagram of an embodiment of an electronic device provided by an embodiment of the present invention. As shown in Figure 3, an embodiment of the present invention provides an electronic device 300, including a memory 310, a processor 320, and a computer program 311 stored in the memory 310 and executable on the processor 320. When the processor 320 executes the computer program 311, the following steps are performed:

[0155] S1, obtaining independent wheel speed time stamp signals of each tire of the vehicle, and calculating the real-time rolling characteristics of each tire according to the wheel speed time stamp signals;

[0156] S2, obtaining a real-time vehicle monitoring signal, identifying the current operating condition of the vehicle based on changes in the status bits of specific signal values ​​or regular changes in the signal in the vehicle monitoring signal, and analyzing, disabling, or compensating for the real-time rolling characteristics based on the current operating condition to correct abnormal changes in the tire rolling characteristics caused by the current operating condition;

[0157] S3, based on the corresponding relationship between the tire rolling characteristics and the tire pressure, calculating the tire pressure according to the corrected tire rolling characteristics.

[0158] Please refer to Figure 4, which is a schematic diagram of an embodiment of a computer-readable storage medium provided by the present invention. As shown in Figure 4, this embodiment provides a computer-readable storage medium 400 on which a computer program 411 is stored. When the computer program 411 is executed by a processor, the following steps are implemented:

[0159] S1, obtaining independent wheel speed time stamp signals of each tire of the vehicle, and calculating the real-time rolling characteristics of each tire according to the wheel speed time stamp signals;

[0160] S2, obtaining a real-time vehicle monitoring signal, identifying the current operating condition of the vehicle based on changes in the status bits of specific signal values ​​or regular changes in the signal in the vehicle monitoring signal, and analyzing, disabling, or compensating for the real-time rolling characteristics based on the current operating condition to correct abnormal changes in the tire rolling characteristics caused by the current operating condition;

[0161] S3, based on the corresponding relationship between the tire rolling characteristics and the tire pressure, calculating the tire pressure according to the corrected tire rolling characteristics.

[0162] Embodiments of the present invention provide an indirect tire pressure monitoring method, system, electronic device, and storage medium suitable for complex driving conditions. These methods identify the vehicle's current operating state based on real-time monitoring signals, with a particular focus on identifying and processing special operating conditions in actual vehicle use, particularly driving conditions that may affect tire rolling characteristics, such as braking and braking, mountain roads (uphill and downhill, and turning), load-variable conditions, dynamic driving, and rough roads. In a specific implementation, actual vehicle calibration is performed for a specific vehicle model, and comparison parameters are set for each type of vehicle's operating characteristic values. Because different types and degrees of special driving conditions have different impacts on the tire's original rolling characteristics, the tire rolling characteristics are processed through analysis, disabling, or compensation based on the different driving conditions and degrees. Abnormal changes in the tire rolling characteristics caused by special driving conditions are corrected, so that changes in the tire's relative rolling radius characteristics and vibration spectrum characteristics are only strongly correlated with changes in tire pressure. This eliminates the connection between tire rolling characteristics and unconventional driving conditions. This method can be used to determine tire pressure and implement real-time tire pressure monitoring, improving the efficiency and accuracy of indirect tire pressure monitoring in actual vehicle use and reducing the system's false positive rate. Since the vehicle monitoring signals are all original vehicle sensor signals, and the calculation and storage are all based on the ESC controller, there is no need to install other sensors and no additional hardware costs.

[0163] It should be noted that, in the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0164] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0165] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0166] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0167] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0168] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0169] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. An indirect tire pressure monitoring method applicable to complex driving conditions, characterized in that, it includes: S1. Obtain the wheel speed timestamp signals of each tire of the vehicle, and calculate the real-time rolling characteristics of each tire according to the wheel speed timestamp signals; S2. Obtain the real-time vehicle monitoring signals, identify the current vehicle condition according to the state bit change of specific signal values or the regular change of signals in the vehicle monitoring signals, and analyze, disable or compensate the real-time rolling characteristics according to the current condition to correct the abnormal changes in the tire rolling characteristics caused by the current condition; S3. Based on the correspondence between the rolling characteristics of the tire and the tire pressure, calculate the tire pressure according to the corrected tire rolling characteristics.

2. The indirect tire pressure monitoring method applicable to complex driving conditions according to claim 1, characterized in that, in step S1, the real-time rolling characteristics include the vibration frequency domain characteristic Fi and the relative rolling radius characteristic Ri.

3. The indirect tire pressure monitoring method applicable to complex driving conditions according to claim 2, characterized in that, step S2 includes: Obtain the real-time brake flag signal from the vehicle monitoring signals, and obtain the moment t when braking occurs according to the change of the status bit of the brake flag signal 0 and the moment t when braking is released 1 ; Obtain the rolling angular velocity change values Δω corresponding to each tire from the wheel speed timestamp signals of each tire FL 、Δω FR 、Δω RL and Δω RR , and obtain the moment t when the tire rolling angular velocity is zero 2 , and calculate the braking degree B of the vehicle through the following formula: ω=1 / 4(Δω FL +Δω FR +Δω RL +Δω RR ) (2), B = ω / Δt (3), where Δt is the actual braking time and ω is the change value of the rolling angular velocity of the tire; Compare the calculated braking degree B with a preset vehicle braking recognition parameter B 0 The vehicle braking recognition parameter B 0 is set according to the actual vehicle calibration result: If B ≤ B 0 , it is determined that the current vehicle condition is normal braking and there is no need to correct the tire rolling characteristics; If B > B 0 , it is determined that the current vehicle condition is an emergency brake, and the analysis of the relative rolling radius feature Ri of the tire is disabled to stop the calculation and update of the relative rolling radius feature Ri until it is determined that the emergency brake is released.

4. The indirect tire pressure monitoring method applicable to complex driving conditions according to claim 2, characterized in that, step S2 includes: Obtain the real-time lateral acceleration L and yaw rate Y according to the vehicle monitoring signals, and calculate the discrete degree D(L) of the lateral acceleration and the discrete degree D(Y) of the yaw rate within k sampling periods respectively: where Li is the lateral acceleration data collected in the i-th cycle, i ∈ [1, k], Yj is the yaw rate data collected in the i-th cycle, j ∈ [1, k], and k is a natural number; Calculate the real-time turning condition weighted value W(h) according to the dispersion degree D(L) of the lateral acceleration and the dispersion degree D(Y) of the yaw rate: where m and n are weighting parameters, which are set according to the vehicle model parameters and the real vehicle turning characteristics; Compare the turning condition weighted value W(h) with the weight threshold value W 0 to determine whether the current condition is a turning condition: If W(h) < W 0 , it is determined that the current is not a turning condition, and there is no need to correct the tire rolling characteristics; If W(h) > 2W 0 , it is determined that the current is in the combined condition of turning and loading, and the analysis of the relative rolling radius characteristic Ri and the vibration frequency domain characteristic Fi of the tire is disabled to stop the calculation and update of the real-time rolling characteristics of the tire until it is determined that the current condition ends; If W 0 ≤W(h)≤2W 0 , it is determined that the current is in a turning condition, and the real-time yaw rate information Y(t) is calculated by the following formula (7): Y(t) = ±[((R FL + R RL ) / 2 - (R FR + R RR ) / 2) / A (7), Among them, A is the vehicle wheel track parameter, R FL , R RL , R FR and R RR are respectively the relative rolling radius values of each wheel of the vehicle; calculate the wheel speed difference ΔR between the tires on both sides of the vehicle through the following formula (8): ΔR = ±AY(t) (8), where the positive and negative of ΔR are related to the turning direction; compensate the wheel speed difference ΔR between the tires on both sides of the vehicle into the relative rolling radius characteristic Ri of the tire on the side where the rolling radius drops abnormally.

5. The indirect tire pressure monitoring method applicable to complex driving conditions according to any one of claims 2 to 4, characterized in that, step S2 includes: Select two frequencies with the highest influence degree of road surface excitation, and respectively extract the frequency domain characteristic values corresponding to the two frequencies from the vibration frequency domain characteristics Fi of each tire of the vehicle to obtain the first frequency domain characteristic value and the second frequency domain characteristic value; According to the changes of the amplitudes of the first frequency domain characteristic value and the second frequency domain characteristic value over time, combined with the changes of the tire relative rolling radius characteristic Ri over time, judge whether each tire is in a non-proportional underpressure or proportional underpressure state currently: If it is determined to be in a non-proportional underpressure or proportional underpressure state, stop the rough road surface identification; ​ If it is determined that the vehicle is not in a state of non - proportional undervoltage or proportional undervoltage, the average values of the first - frequency frequency - domain eigenvalues and the second - frequency frequency - domain eigenvalues are calculated respectively to obtain the first - frequency vibration characteristic compensation value Power1 and the second - frequency vibration characteristic compensation value Power2 that reflect the road surface roughness, and the first - frequency vibration characteristic compensation value Power1 and the second - frequency vibration characteristic compensation value Power2 are compensated into the vibration frequency - domain characteristics Fi of each tire of the vehicle.

6. An indirect tire pressure monitoring method applicable to complex driving conditions according to claim 5, characterized in that, judging whether each tire is currently in a state of non - proportional undervoltage or proportional undervoltage according to the changes of the amplitudes of the first - frequency frequency - domain eigenvalue and the second - frequency frequency - domain eigenvalue over time, combined with the change of the relative rolling radius characteristic Ri of the tire over time, includes: If the amplitudes of the first - frequency frequency - domain eigenvalue, the second - frequency frequency - domain eigenvalue, and the relative rolling radius characteristic Ri of the tire change synchronously over time, it is determined that the current state is four - wheel non - proportional undervoltage; If the relative rolling radius characteristic Ri of the tire changes little in a certain time period, and the amplitudes of the first - frequency frequency - domain eigenvalue and the second - frequency frequency - domain eigenvalue change in a consistent pattern over time, it is determined that the current state is four - wheel proportional undervoltage.

7. An indirect tire pressure monitoring method applicable to complex driving conditions according to claim 3, characterized in that, Step S2 includes: Obtaining the longitudinal acceleration signal Xt based on the time domain from the vehicle - wide monitoring signal, and obtaining the smoothed and reliable longitudinal acceleration filtered value St after filtering through Equation (9): S t = αXt+(1 - α)S t-1 (9), where α is the filtering parameter, and S t-1 is the filtered value of the longitudinal acceleration at the previous moment; Obtaining the wheel speed of the driven wheels of the vehicle according to the wheel speed timestamp signal of the wheels, and calculating the actual acceleration Area of the vehicle based on the change rate of the wheel speed of the driven wheels of the vehicle within a unit time; Calculate the average value Vi of the wheel speeds of the two driven wheels and the average value Vo of the wheel speeds of the two driving wheels based on the wheel speed timestamp signals of the four wheels, and calculate the driving slip ratio H based on the average value Vi of the wheel speeds of the two driven wheels and the average value Vo of the wheel speeds of the two driving wheels: Judging whether the vehicle is currently in an uphill / downhill condition according to the longitudinal acceleration filtered value St, the actual acceleration Area of the vehicle, and the driving slip ratio H; If St > H / H 0 Area, it is determined that the vehicle is in the up / down slope working condition; where H 0 is the slip rate threshold; When in uphill or downhill working conditions, if H < H 0 , there is no need to correct the tire rolling characteristics.

8. An indirect tire pressure monitoring method applicable to complex driving conditions according to claim 7, characterized in that, Step S2 includes: Obtaining the torque fluctuation signal T(h) based on the time domain from the vehicle - wide monitoring signal, and calculating the dynamic driving degree Tva of the vehicle in combination with the torque value T during uniform driving; T va = T(h) / T (11) Judging whether the vehicle is in a dynamic driving condition according to the dynamic driving degree Tva and the driving slip ratio H; If H≥H 0 , and Tva>T C , it is determined that the vehicle is in a dynamic driving condition, where T C is the dynamic driving threshold, and the value of T C is set according to experience; For the dynamic driving condition, calculate the gain of the relative rolling radius of the driving wheel through the following Equation (12): R = R 驱动 *f(H) (12), where f(H) is a gain function related to the current driving slip ratio, R 驱动 is the relative rolling radius of the driving wheel, and R is the relative rolling radius of the driving wheel after calculating the gain; Update the relative rolling radius R of the driving wheel after gain to the relative rolling radius characteristic Ri.

9. An indirect tire pressure monitoring method applicable to complex driving conditions according to claim 8, characterized in that, Step S2 further includes: If it is determined that the vehicle is not currently in a braking condition, an uphill / downhill condition, or a dynamic driving condition, and it is determined that there is a load change according to the longitudinal acceleration filtered value St, it is determined that the vehicle is currently in a loading condition; Obtain the longitudinal acceleration change S corresponding to different vehicle loads M recorded during the actual vehicle calibration phase T负载 and the longitudinal acceleration change S when there is no load T空载 as well as the relative rolling radius change ΔR of the coaxial tires load , when the load M is within the vehicle load range, the following relationship holds: ΔR load = p(S T负载 - S T空载 ) (13), where p is a proportionality coefficient; Substitute the longitudinal acceleration change S corresponding to the current vehicle load T负载 into Equation (13) to calculate the relative rolling radius change ΔR of the coaxial tires corresponding to the current load load ; Compensate the calculated change ΔR in the relative rolling radius of the coaxial tires load into the relative rolling radius characteristic Ri of the tires with abnormal changes caused by the loading conditions.

10. An indirect tire pressure monitoring system applicable to complex driving conditions, characterized in that, including: A decomposition module, configured to obtain the wheel speed timestamp signals of each tire of the vehicle independently, and calculate the real-time rolling characteristics of each tire according to the wheel speed timestamp signals; A correction module, configured to obtain the real-time vehicle monitoring signals, identify the current working condition of the vehicle according to the state bit change of a specific signal value or the regular change of the signals in the vehicle monitoring signals, and analyze, disable or compensate the real-time rolling characteristics according to the current working condition, so as to correct the abnormal change of the tire rolling characteristics caused by the current working condition; A calculation module, configured to calculate the tire pressure according to the corrected tire rolling characteristics based on the corresponding relationship between the rolling characteristics of the tire and the tire pressure.

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