CN106143497A - Tire pressure monitoring method for computing data - Google Patents

Abstract

The invention provides a kind of tire pressure monitoring method for computing data, the method includes: read vehicle wheel rotational speed data from vehicle bus, deletes the invalid data of travel conditions interference, sets up the not enough judgment criterion of tire pressure, determine warning threshold, it is achieved data acquisition, algorithm process and warning output.The present invention proposes a kind of tire pressure monitoring method for computing data, only carries out calculation process by existing sensor element, when driving dynamic monitoring tire pressure effectively, saves hardware cost and simultaneously improves computing accuracy rate.

Description

Tire pressure monitoring method for computing data

Technical field

The present invention relates to wagon control, particularly to a kind of tire pressure monitoring method for computing data.

Background technology

With the continuous growth of China's automobile quantity, the security of running car becomes more and more important.And guarantee automobile Work in the range of regulation allows of all parts state is significant to promotion energy-saving and emission-reduction.Especially in tire pressure monitoring side Face, radio tire pressure monitoring system has become the main direction of studying promoting safe driving, energy-conservation driving and intelligent travelling crane.Prison Examining system automatically monitors tire pressure when vehicle travels, and when finding to alert when tire is in unusual condition, promotes to drive The person of sailing adopts an effective measure, it is to avoid cause danger, and also can be prevented effectively from oil consumption increases, it is ensured that vehicle is most preferably handling and comfortable Property.But in the prior art, tire pressure monitoring system is many by signal acquiring system collecting vehicle wheel speed step-by-step counting evidence, but need Want external signal processing module, and cannot monitor tire pressure when speed is too high.

Content of the invention

For solving the problem existing for above-mentioned prior art, the present invention proposes a kind of tire pressure monitoring method for computing data, Including:

Read vehicle wheel rotational speed data from vehicle bus, delete the invalid data of travel conditions interference, set up tire pressure deficiency and sentence Disconnected criterion, determines warning threshold, it is achieved data acquisition, algorithm process and warning output.

Preferably, the invalid data of described deletion travel conditions interference, comprising:

According to the vehicle data obtaining from vehicle-mounted monitoring module and each axle acceleration of vehicle obtaining from acceleration transducer, Judge travel conditions, if front backward acceleration is a_x, transverse acceleration is a_y, normal acceleration is a_z, the weight of each acceleration Coefficient is k₁,k₂,k₃, acceleration rate threshold is set as T_a, g is acceleration of gravity, then:

T_a=k₁|a_x|+k₂|a_y|+k₃|(a_z-g)|

Work as T_aWhen exceeding setting threshold value, it is determined that vehicle is in acceleration and deceleration, jolts or turn condition, discards present sample Point, and all sampled points in steering indicating light signal time section will be had all to abandon, and speed v meets, v_L<v<v_H

v_L, v_HIt is respectively the minimum and max. speed that tire pressure monitoring system is operated；

After discarding the Null Spot being not suitable for carrying out tire pressure monitoring, carry out fragmented storage；

Described set up the not enough judgment criterion of tire pressure, determine warning threshold, farther include:

It according to the difference of each vehicle speed intervals, after available point is classified, is stored as the data that n array is a group, After Coutinuous store 3 groups, buffer carries out Overflow handling；After spilling, system is first filtered processing, erased noise point, then continuously Judge whether certain wheel is the not enough state of tire pressure for three times；If certain wheel is in the not enough state of tire pressure for continuous three times, then leak The acceleration calculation of gas speed；If acceleration calculation result exceedes predetermined threshold value, then determine that it is rapid air leakage；Otherwise, then it is Leak gas at a slow speed, after determining the not enough state of certain tire pressure taken turns, carry out different warning output according to different states；

Wherein said fragmented storage also includes: set small unit interval section as T, D_ijFor the vehicle wheel rotational speed sample value collecting I=1,2,3 ..., 8, j=1,2,3 ..., 3n, the distance that each sampled point travels near tiny time section T is

S_ij=D_ijT

S in formula_ijThe distance travelling for the time near each sampled point, the available point number that n is gathered by sampling time section；

After the full 3n of sampled point collection, collection point is one section with n and is divided into 3 sections, calculate the mean angular velocity of each section

R in formula_cFor vehicle wheel roll radius；

When sampling, speed is divided into interval by 10,000 ms/hour for unit, then each sampling point is put into each interval right The memory block answered；Calculate section mean speed v of every n point_kFor:

v_ijThe speed sample value collecting for vehicle speed sensor.

The present invention compared to existing technology, has the advantage that

The present invention proposes a kind of tire pressure monitoring method for computing data, is only entered at row operation by existing sensor element Reason, when driving dynamic monitoring tire pressure effectively, save hardware cost and simultaneously improve computing accuracy rate.

Brief description

Fig. 1 is the flow chart of tire pressure monitoring method for computing data according to embodiments of the present invention.

Detailed description of the invention

Hereafter provide retouching in detail to one or more embodiment of the present invention together with the accompanying drawing of the diagram principle of the invention State.Describe the present invention in conjunction with such embodiment, but the invention is not restricted to any embodiment.The scope of the present invention is only by right Claim limits, and the present invention covers many replacements, modification and equivalent.Illustrate in the following description many details with Thorough understanding of the present invention is just provided.These details are provided for exemplary purposes, and without in these details Some or all details also can realize the present invention according to claims.

An aspect of of the present present invention provides a kind of tire pressure monitoring method for computing data.Fig. 1 is according to embodiments of the present invention Tire pressure monitoring method for computing data flow chart.

The present invention proposes the tire pressure monitoring method based on vehicle wheel rotational speed data, selects wheel rotation speed signals to supervise as tire pressure The initial data surveyed, the vehicle wheel rotational speed data reading from vehicle bus, get rid of travel conditions in conjunction with multisensor multi-parameter algorithm Interference, deletes the invalid data affecting tire pressure monitoring；Set up algorithm model and the not enough judgment criterion of tire pressure of monitoring tire pressure, to police Accuse threshold value to be determined, determine aposematic mechanism, it is achieved data acquisition, algorithm process and warning output.Vehicle-mounted monitoring module includes Wireless communication layer, sensing layer and application layer.Wireless communication layer sets up the passage with vehicle communication, processes communication sequential, completes letter Breath is mutual.The agreement that vehicle-mounted monitoring module standard need to be supported by wireless communication layer resolves, and makes this system can meet currently Meet the vehicle of vehicle-mounted monitoring module standard.Sensing layer formulates perfect correspondence with foreign country standard, passes to meet reliable and stable data Defeated needs, it is ensured that correct, effective vehicle data can be got, in order to tire pressure monitoring system carries out tire pressure monitoring core calculation The process of method, and finally export tire pressure result.Application layer is the modules formulated according to software, performs the related of default Function, comprising: information collection module, acceleration calibration and acquisition module, vehicle wheel rotational speed data acquisition module, tire self-inspection mould Block, travel conditions grade module, tire pressure monitoring computing module and warning output module.The realization of each process is based on corresponding The driver of equipment.

Tire pressure monitoring system of the present invention realizes monitoring based on vehicle wheel rotational speed data to tire pressure.Automobile is running on an equal basis During distance, the number of turns of each wheel rolling process and its rolling radius are inversely proportional to, and vehicle wheel rotational speed is inversely proportional to its rolling radius.Wheel The step-by-step counting that the speed probe of upper installation sends also is inversely proportional to its rolling radius.Tire pressure monitoring system carries out abnormal alert Announcement, is by eliminating non-tire pressure factor, determining and after unitized process correction, determine that the primary condition of each tire is consistent, then Vehicle wheel rotational speed after correction process or the speed probe step-by-step counting after process are inversely proportional to the tire pressure of this wheel.This When, record each step-by-step counting taken turns, obtain each relation taking turns air pressure.The tire not enough according to tire pressure and the ratio of normal tire difference Example threshold value i.e. reflects the draught head of two-wheeled.

During each vehicle launch, system is waken up in resting state, proceeds by System self-test, if system hardware is just Often, vehicle-mounted monitoring module and acceleration transducer output are normal, then system starts；During first use, user chooses whether Carry out tire calibration, make system eliminate the impact on vehicle wheel rotational speed data for the non-tire pressure factor；When car speed is at system work model Enclosing interior and when being in smooth-ride state, system enters the training study stage, the unitized of driving wheel speed data-signal of going forward side by side Process, eliminate front and back wheel tire pressure normal when requirement inconsistent, the impact on tire pressure monitoring precision such as tire wear；Acquisition is passed through The vehicle wheel rotational speed data of vehicle-mounted universal serial bus output；The travelling data of vehicle, comprises speed, turn signal etc.；Pass from acceleration Each axle acceleration of sensor output, as the basis for estimation as travel conditions；According to speed in the change of time response, Delete invalid data, carry out segmentation summation to data, pass through mean value computation process afterwards again, it is achieved the identification of abnormal tyre pressure；Root According to different travel conditions, select suitable tire pressure monitoring algorithm；In the case that tire pressure is judged to abnormal, carry out alerting defeated Go out, remind driver to note taking measures in time.

During System self-test, comprising to check that whether supply voltage is normal, whether system can lead to electronic control unit Letter, whether acceleration transducer normally works, and whether display screen normally shows.After the engine ignition of vehicle, system enters certainly Inspection pattern, first, system acquisition supply voltage, it is judged that whether it is within normal voltage range, secondly, monitoring and automobile electricity Sub-control unit whether proper communication, the single-chip microcomputer of system sends initialization directive to the electronic control unit of automobile.If electronics Control unit has response, then self-inspection success；If electronic control unit is in the given time without response, then fail self-test, system is entered Row is restarted；Whether monitoring acceleration transducer normally works, and reads each axle acceleration when pre-test.If the acceleration reading exists In allowed band, determine its normal work；If exceeding allowed band, then read three times continuously；Three times all beyond allowed band, really Determine acceleration transducer abnormal, carry out warning output；Finally, sending initialization directive to display screen, if receiving response, then proving Display screen is normal；If without response, it is determined that display screen is abnormal, carry out warning output.

It follows that according to the vehicle data obtaining from vehicle-mounted monitoring module and each axle of vehicle obtaining from acceleration transducer Acceleration, judges travel conditions, according to different travel conditions, determines the process of tire pressure monitoring.

If front backward acceleration is a_x, transverse acceleration is a_y, normal acceleration is a_z, the weight coefficient of each acceleration is k₁,k₂,k₃, acceleration rate threshold is set as that Ta, g are acceleration of gravity, then:

T_a=k₁|a_x|+k₂|a_y|+k₃|(a_z-g)|

Work as T_aWhen exceeding setting threshold value, it is determined that vehicle is in acceleration and deceleration, jolts or turn condition, then discard and currently adopt Sampling point.And all sampled points in steering indicating light signal time section will be had all to abandon.

And speed v meets, v_L<v<v_H

v_L, v_HIt is respectively the minimum and max. speed that tire pressure monitoring system is operated.

Get the rotary speed data of each wheel from vehicle-mounted monitoring module interface, discard according to travel conditions information and be not suitable for After carrying out the Null Spot of tire pressure monitoring, after screening, carry out fragmented storage.According to the difference of each vehicle speed intervals, effectively After point is classified, being stored as the data that n array is a group, after Coutinuous store 3 groups, buffer carries out Overflow handling.Overflow Rear system is first filtered processing, erased noise point, judges whether certain wheel is the not enough state of tire pressure for continuous afterwards three times.If certain Wheel is in the not enough state of tire pressure for continuous three times, then carry out the acceleration calculation of leakage rate.If this value exceedes predetermined threshold value, Then determine that it is rapid air leakage；Otherwise, then for leaking gas at a slow speed.After determining the not enough state of certain tire pressure taken turns, according to different states Carry out different warning output.

Specifically, according to speed in the change of time response, carrying out segmentation summation, raising system carries out tire pressure monitoring Precision and accuracy.Assuming that vehicle wheel rotational speed keeps constant in tiny time section, if small unit interval section is T.D_ij(i=1, 2,3 ..., 8, j=1,2,3 ..., 3n) it is the vehicle wheel rotational speed sample value collecting.Each sampled point is attached in tiny time section T The distance of nearly traveling is

S_ij=D_ijT

S in formula_ijThe distance travelling for the time near each sampled point, the available point number that n is gathered by sampling time section；

After the full 3n of sampled point collection, collection point is one section with n and is divided into 3 sections, calculate the mean angular velocity of each sectionAppoint Anticipate one section mean angular velocity useRepresent.

R in formula_cFor vehicle wheel roll radius.

When sampling, speed is divided into interval by 10,000 ms/hour for unit, then each sampling point is put into each interval right The memory block answered.Because of the discontinuity of sampled point, need to calculate section mean speed v of every n point_kFor:

v_ijThe speed sample value collecting for vehicle speed sensor

In order to reduce the error that tire difference introduces, before calculating tire pressure, carry out unitized place to wheel rotation speed signals Reason, obtains the identical characteristic parameter of each wheel, and this unitized process is exactly that wheel original pulse is counted N_iIt is each right to be multiplied by Correction coefficient k of the step-by-step counting answered_i, it is converted into calibration pulse counting SN_i, i.e. calculated by below equation:

SN_i=k_i·N_i=1800Zk_iA_i/ π vnT i=1,2,3,4

Wherein A_iRotation angle values for wheel standards n the cycle；V is average speed；Z is the number of teeth of gear；T is predefined Normal period.

Calculate the error of i-th tire standards step-by-step counting and actual pulse counting and obtain anglec of rotation error delta N_i:

${\mathrm{\&Delta;N}}_i=\left|\frac{{\mathrm{SN}}_i-N_i}{N_i}\right|$

Try to achieve Δ N when all wheels are normal tire pressure_iWhen≤2%, determine that data are correct, by k_iAs each arteries and veins taken turns The correction coefficient of punching counting.

Comparison by i-th wheel anglec of rotation and other three-wheel anglec of rotation averages.Calculate other three in addition to i-th takes turns The average of the anglec of rotation of tire

And i ≠ j

Then the relative error Δ ā of i-th anglec of rotation taken turns and other three-wheel anglec of rotation averages is obtained_i:

$\mathrm{\&Delta;}{\stackrel{\&OverBar;}{A}}_i=\left|\frac{A_i-{\stackrel{\&OverBar;}{A}}_i}{{\stackrel{\&OverBar;}{A}}_i}\right|$

WhenWhen exceeding threshold value set in advance, then judge the pressure anomaly of this tire.

For getting rid of the impact on wheel rotation speed signals data for the non-tire pressure factor, use procedure below to different vehicle speed intervals Warning threshold is calibrated, and reduces the rate of false alarm of system.

Speed being maintained at each vehicle speed intervals constant, the original pulse counting sending every speed sensor is recorded Come, and carried out unitized process.Then only change the tire pressure of single tire, try to achieve the not enough tire km pulsimeter of tire pressure Number.Not enough for tire pressure warning is divided into three grades: i.e. slight, moderate, severe.It is then converted to proportion threshold value T_ij, i represents tire sequence number, j Represent warning level, as the final warning threshold setting.

In time response, the speed of gas leakage be based on the variable quantity of vehicle wheel rotational speed data rate of change in time and Determine.According to the vehicle wheel rotational speed data after process, gather three sections of data segments being made up of n sampled point and judge whether leakage Gas, if continuous three times are all judged to gas leakage, determine that this tire is in gas leakage state, and records each ratios delta N_ik, wherein k= 1,2,3 represent three judgements.If three judgements are all higher than slight leak threshold T_ik, it may be assumed that

ΔN_i1＞ T_i1

ΔN_i2＞ T_i2

ΔN_i3＞ T_i3

Then this is taken turns and is judged to gas leakage.Then judge to be in which rank of gas leakage state, the average of three ratios of calculating:

RelativelyAnd T_ij, gas leakage state can be drawn.To different tire pressures, not enough state carries out different sound and figure As display, inform the state of driver's tire, remind driver to take suitable measure.

The leakage rate of tire is extracted from the tire pressures of three times change.If leakage rate is h_i, then

h_i=[(Δ N_i2-ΔN_i1)/ΔN_i2]/2+[(ΔN_i3-ΔN_i2)/ΔN_i2]/2

Work as h_iWhen exceeding predetermined threshold value, represent that tire pressure has significant change in this segment limit, it is determined that be rapid air leakage, otherwise It is judged to leak gas at a slow speed.

Another alternative embodiment of the present invention is estimated before and after each tire to stress Cx and rolling radius R simultaneously.Arrange Object function:

Ma=2Cx (V-R ω) V-η V²；

M and a is respectively gross mass and the acceleration of vehicle, and V is speed, and ω is driving wheel angular speed, and η is constant factor； Above formula is designated as

E=ma=F (T, B), wherein T=(ω, V)；B=(Cx, R)

1. select initial point；x⁽¹⁾=(Cx, R), initial step length (SPAN1, SPAN2) > 0, e₁=(1,0), e₂=(0,1)； Step size increments λ > 1, increments amount β ∈ (0,1), accelerated factor θ, resolution ratio τ, ma initial approximation solution E_k, two tuples T are initially near Like solution T_k, put y⁽¹⁾=x⁽¹⁾, search circulation step number r=1.

2. for i=1,2:

If

∑_{K ∈ [1, n]}[E_k-F(T_k,y⁽¹⁾+SPAN1(i)*e_i)]²＜ [E_k-F(T_k,y⁽ⁱ⁾)]

Then put y⁽ⁱ⁺¹⁾=y⁽ⁱ⁾+SPAN1(i)*e_i, SPAN1 (i)=SPAN1 (i) * λ；

If otherwise

∑_{K ∈ [1, n]}[E_k-F(T_k,y⁽¹⁾+SPAN1(i)*e_i)]²≥[E_k-F(T_k,y⁽ⁱ⁾)]

Then put y⁽ⁱ⁺¹⁾=y⁽ⁱ⁾-SPAN1(i)*e_i, SPAN1 (i)=SPAN1 (i) * λ；

If

∑_{K ∈ [1, n]}[E_k-F(T_k,y⁽¹⁾+SPAN2(i)*e_i)]²＜ [E_k-F(T_k,y⁽ⁱ⁾)]

Then put y⁽ⁱ⁺¹⁾=y⁽ⁱ⁾-SPAN2(i)*e_i, SPAN2 (i)=SPAN2 (i) * λ；

If otherwise

∑_{K ∈ [1, n]}[E_k-F(T_k,y⁽¹⁾+SPAN2(i)*e_i)]²≥[E_k-F(T_k,y⁽ⁱ⁾)]

Then put y⁽ⁱ⁺¹⁾=y⁽ⁱ⁾+SPAN2(i)*e_i, SPAN2 (i) 1=SPAN2 (i) * λ；

Make x^(r+1)=y⁽³⁾,

y⁽¹⁾=x^(r+1)+ θ * (x (r+1) x (r)),

SPAN1=SPAN1* λ,

SPAN2=SPAN2* λ,

Put r=r+1, turn the 2nd step.

If 4. y⁽¹⁾≠x^(r), then y (1)=x is put^(r), turn the 2nd step.

5. if SPAN1 (i)+SPAN2 (i) < τ, i ∈ [1,2], then stop calculating, export x^(r)For approximate optimal solution；Otherwise

SPAN1=SPAN1* β,

SPAN2=SPAN2* β,

Turn the 2nd step.

In sum, the present invention proposes a kind of tire pressure monitoring method for computing data, only passes through existing sensor element Carry out calculation process, when driving dynamic monitoring tire pressure effectively, save hardware cost and simultaneously improve computing accuracy rate.

Obviously, it should be appreciated by those skilled in the art, each module of the above-mentioned present invention or each step can be with general Calculating system realize, they can concentrate in single calculating system, or be distributed in multiple calculating system and formed Network on, alternatively, they can be realized by the executable program code of calculating system, it is thus possible to by they store Performed by calculating system within the storage system.So, the present invention is not restricted to the combination of any specific hardware and software.

It should be appreciated that the above-mentioned detailed description of the invention of the present invention is used only for exemplary illustration or explains the present invention's Principle, and be not construed as limiting the invention.Therefore, that is done in the case of without departing from the spirit and scope of the present invention is any Modification, equivalent, improvement etc., should be included within the scope of the present invention.Additionally, claims purport of the present invention Whole within covering to fall into the equivalents on scope and border or this scope and border change and repair Change example.

Claims (2)

1. a tire pressure monitoring method for computing data, it is characterised in that include:

Read vehicle wheel rotational speed data from vehicle bus, delete the invalid data of travel conditions interference, set up tire pressure not enough judgement standard Then, warning threshold is determined, it is achieved data acquisition, algorithm process and warning output.

2. method according to claim 1, it is characterised in that the invalid data of described deletion travel conditions interference, comprising:

According to the vehicle data obtaining from vehicle-mounted monitoring module and each axle acceleration of vehicle obtaining from acceleration transducer, sentence Disconnected travel conditions, if front backward acceleration is a_x, transverse acceleration is a_y, normal acceleration is a_z, the weight coefficient of each acceleration For k₁,k₂,k₃, acceleration rate threshold is set as T_a, g is acceleration of gravity, then:

T_a=k₁|a_x|+k₂|a_y|+k₃|(a_z-g)|

Work as T_aWhen exceeding setting threshold value, it is determined that vehicle is in acceleration and deceleration, jolts or turn condition, discards current sampling point, and The all sampled points in steering indicating light signal time section will be had all to abandon, and speed v meets, v_L<v<v_H

v_L, v_HIt is respectively the minimum and max. speed that tire pressure monitoring system is operated；

After discarding the Null Spot being not suitable for carrying out tire pressure monitoring, carry out fragmented storage；

Described set up the not enough judgment criterion of tire pressure, determine warning threshold, farther include:

It according to the difference of each vehicle speed intervals, after available point is classified, is stored as the data that n array is a group, continuously After storing 3 groups, buffer carries out Overflow handling；After spilling, system is first filtered processing, erased noise point, then continuous three times Judge whether certain wheel is the not enough state of tire pressure；If certain wheel is in the not enough state of tire pressure for continuous three times, then carry out gas leakage speed The acceleration calculation of degree；If acceleration calculation result exceedes predetermined threshold value, then determine that it is rapid air leakage；Otherwise, then at a slow speed Gas leakage, after determining the not enough state of certain tire pressure taken turns, carries out different warning output according to different states；

Wherein said fragmented storage also includes: set small unit interval section as T, D_ijFor vehicle wheel rotational speed sample value i=collecting 1,2,3 ..., 8, j=1,2,3 ..., 3n, the distance that each sampled point travels near tiny time section T is

S_ij=D_ijT

S in formula_ijThe distance travelling for the time near each sampled point, the available point number that n is gathered by sampling time section；

After the full 3n of sampled point collection, collection point is one section with n and is divided into 3 sections, calculate the mean angular velocity of each section

R in formula_cFor vehicle wheel roll radius；

When sampling, speed is divided into interval by 10,000 ms/hour for unit, then each sampling point is put into each interval corresponding Memory block；Calculate section mean speed v of every n point_kFor:

v_ijThe speed sample value collecting for vehicle speed sensor.