CN103879398A - System and method for testing performance of electronic control unit in air pressure type ABS (anti-lock brake system) - Google Patents

Abstract

The invention provides a system and a method for testing performance of an electronic control unit in an air pressure type ABS (anti-lock brake system). The system comprises an acquisition card, an upper computer and a V/F converter. The method includes the processes of model training and actual measurement. The model training process includes a, connecting an ECU (electronic control unit) passing field test into the system; b, initializing parameters; c, loading a brake system model and testing; d, analyzing a test result curve, evaluating whether brake effect at this time meets national standards or not, if yes, selecting the model as a reference model, and otherwise, returning to the step c. The actual measurement includes e, testing an ECU not subjected to field test under the condition of same initialization parameters, and comparing a test result curve with the curve obtained in the step d so as to judge whether or not a control algorithm is capable of accurately outputting valve control signals in real time and realizing anti-lock braking of tires. The system and the method are low in implementation cost, short in test cycle and high in practical value.

Description

The System and method for of the electronic control unit performance in measuring air pressure type ABS

Technical field

The invention belongs to technical field of automotive electronics, relate to the System and method for of the electronic control unit performance in a kind of measuring air pressure type ABS.

Background technology

ABS(anti-skid brake system) be a kind of automobile active safety device, can effectively prevent wheel lockup and make vehicle keep best direction control, thereby avoid the phenomenon such as whipping, sideslip, track hold facility while improving automobile avoiding barrier and braking on curve, plays vital effect to the safety of vehicle and chaufeur.

ABS is mainly divided into two kinds of hydraulic and air-pressure type, and wherein air-pressure type ABS is applicable to being applied to heavy duty truck, by part compositions such as electronic control unit (ECU, Electronic Control Unit), wheel speed sensors and air pressure electromagnetic valve.Electronic control unit (ECU) is the core component of ABS system, be responsible for accepting the signal of the sensors such as wheel speed, and calculate in real time the acceleration, deceleration degree of slip rate and wheel according to the speed of a motor vehicle detecting, by exporting corresponding control command after analysis, computing and amplification, control the actr work such as electromagnetic valve.When automobile brake, the signal handling capacity of ECU, control algorithm performance etc. directly affects the deceleration and stopping performance of ABS, and therefore the controller performance of ECU is to evaluate the important indicator whether ABS system meets associated safety standard.

At present the test of ECU is mainly contained to following three kinds:

The Ageing Index proving installation of the one, ECU, this device is taking the voltage of different brackets as input, control electric current and voltage are as output, the AC signal that civil power is converted to 0.5 volt of 50Hz by the signal transformer in power subsystem unit constantly triggers ECU action, test stability and the correctness of ECU in the time of intensive work, thereby judge the ageing-resistant performance of ECU.But its shortcoming is to detect ECU the control process during by locking does not have ready-made test equipment at tire, can only carry out by installing the vehicle of this device the wheel-locked testing on road surface;

The electric function detecting device of the 2nd, ECU, this device, by the function of each passage in ECU is detected, as power line voltage detection, input and output voltage detection, switching value, short interruption detection etc., is determined the reliability and stability of ECU entirety.Its shortcoming is to need to use the instrument and equipment that precision voltage source and current source, oscp etc. are numerous in test, and in disparity items testing process, needs to use different equipment, causes whole testing process very complicated, consuming time many.

The input/output port diagnostic device of the 3rd, ECU, the incoming signal of surveying that this device is fed back by ECU by comparative analysis and the output signal being sent by it, thus judge that whether the input/output port work of ECU is normal.This device can carry out diagnosis and detection to the working condition of ECU, but that its shortcoming is measuring accuracy is not high, and the performance of ECU when braking can not be detected really.

The real vehicle road test of the 4th, ECU, the method is by multiple sensors are installed on vehicle, the parameters such as the wheel speed while detecting car brakeing in real time, and be sent to the ECU being arranged on real vehicle, after ECU analyzing and processing, provide suitable control command, can intuitively, effectively detect the performance of ECU.But when its shortcoming is road surface real train test, due to the property complicated and changeable of damped condition make the controllability of test parameters and conformability very poor, cause the method for real vehicle test ECU to be difficult to be used widely.

To sum up, be mainly Ageing Index, the electric function characteristic of test ECU to the test of ECU at present, and input/output port is diagnosed; Or directly use the performance of real vehicle road test method test ECU.Nowadays, at home and abroad there is no method and the computer system of ECU controller performance being tested with computer software and hardware device.

Summary of the invention

The present invention is based on hardware-in-loop simulation technology, has solved the real vehicle road test inefficiency of ECU in prior art, and the while is due to the property complicated and changeable of damped condition, the problem that the controllability of test parameters and conformability are poor.The present invention can test accurately to the signal handling capacity of ECU, communication capacity and control algorithm performance etc.Conveniently carry out large batch of detection, work efficiency is high.

The technology used in the present invention solution is as follows:

A system for electronic control unit performance in measuring air pressure type ABS, is characterized in that, comprises capture card, upper computer and V/F changer;

The digital input interface of capture card connects the output interface of ECU to be measured, and the digital output interface of capture card is connected with upper computer, passes to upper computer for the valve control signal that ECU to be measured is produced;

The D/A mouth of capture card is connected with the input end of V/F changer, and the mouth of V/F changer is connected with the input interface of ECU to be measured, passes to ECU for the wheel speed signal that upper computer is produced.

Described upper computer comprises auto model, tire model, brake model and braking pressure model database.

A method for electronic control unit performance in measuring air pressure type ABS, adopts the system of the electronic control unit performance in measuring air pressure type ABS claimed in claim 2, it is characterized in that, comprising: model training process and actual measurement process;

Described model training process comprises the following steps:

A: the ECU of real vehicle test passes is replaced to ECU connecting system to be measured;

B: initialization vehicle parameter and road conditions parameter; Described vehicle parameter comprises carload lot, radius of wheel, number of gears, acceleration due to gravity constant, Automobile Maximum brake-pressure, the minimum brake-pressure of automobile, drg brake factors, Cars ' Moment of Inertia and braking rate of onset; Initialization road conditions parameter refers to selects a kind of condition of road surface, thereby determines peak adhesion coefficient μ _h; Slip rate corresponding adhesion value μ while being 100% _g; Adhesion value is μ _htime corresponding slip rate S _c, S _cit is optimal slip ratio;

C: load one group of auto model, tire model, brake model and braking pressure model in the analysis module of upper computer;

D: upper computer passes to braking rate of onset the ECU of real vehicle test passes;

E: produce valve control signal by the ECU of real vehicle test passes, described valve control signal comprises " 00 ", " 11 " and " 10 ", represents respectively " supercharging ", " decompression " and " pressurize ";

F: the valve control signal that capture card collection is produced by the ECU of real vehicle test passes, sends upper computer to;

G: upper computer calculates wheel speed and the slip rate of this time braking according to auto model, tire model, brake model and the braking pressure model of valve control signal and step c loading;

H: upper computer shows wheel speed/reference speed-time curve and slip rate-time curve, judge according to curve whether this braking effect meets national standard [ABS testing standard GB13594-2003, particularly, whether observe slip rate and near optimal slip ratio, in 10% scope, change, if within the scope of this, adhesion value approaches peak adhesion coefficient, illustrate that whole braking procedure takes full advantage of the adhesion value that ground provides, good braking effect], if the national standard of not meeting is returned to step c; Otherwise select the model this time loading as the benchmark model of testing;

Described actual measurement process specifically comprises:

I: by ECU connecting system to be measured;

J: by step b initialization vehicle parameter and road conditions parameter, initial speed of braking is passed to ECU to be measured by upper computer;

K: produce valve control signal by ECU to be measured;

L: the valve control signal that capture card collection is produced by ECU to be measured, sends upper computer to;

M: upper computer calculates wheel speed and the slip rate of this time braking according to the benchmark model of valve control signal and loading, according to braking rate of onset v ₀, automobile body deceleration

and formula

obtain reference speed;

N: upper computer shows wheel speed/reference speed-time curve and slip rate-time curve, and the curve that the ECU of the curve that this is obtained and real vehicle test passes obtains by benchmark model contrasts, judges the performance without the ECU of real vehicle test.

Condition of road surface in described step b is dry asphalt coating, moist earth road surface, snowy road surface or accumulated ice road surface.

Described auto model is single-wheel auto model, two-wheel vehicles model or four wheeler model;

Described tire model is theoretical model, magic formula model or bilinear model;

Described brake model is the linear model of simplifying;

Described braking pressure model is the braking pressure model based on System Discrimination modeling, Experiment Modeling or Method of Physical Modeling.

Auto model in described step c is single-wheel auto model, and its equation of motion is

$I\stackrel{\·}{w}=\mathrm{\μNR}-M_b$

Wherein, I is Cars ' Moment of Inertia, unit: kgm ²;

for wheel angular acceleration, unit: rad/s ²; R is radius of wheel, unit: m; μ is adhesion value; N is the normal reaction of wheel to ground; M _bfor wheel braking moment, unit: Nm;

Tire model in described step c is bilinear model: the pass between adhesion value μ and slip rate S is

$\left\{\begin{array}{cc}\mathrm{\μ}=\frac{{\mathrm{\μ}}_h}{{\mathrm{\μ}}_g}S& S\≤S_c\\ \mathrm{\μ}=\frac{{\mathrm{\μ}}_h-{\mathrm{\μ}}_g{S}_c}{1-S_c}-\frac{{\mathrm{\μ}}_h-{\mathrm{\μ}}_g}{1-S_c}S& S>S_c\end{array}\right.$

Wherein, μ _hfor peak adhesion coefficient; μ _gcorresponding adhesion value while being 100% for slip rate; S _cfor adhesion value is μ _htime corresponding slip rate, i.e. optimal slip ratio;

Brake model in described step c is the linear model of simplifying: acting on lock torque on wheel and the mathematical relation of brake-pressure is

$\left\{\begin{array}{cc}{M}_b=0& p<p_0\\ M_b=C^{*}(p-p_0)& p\&GreaterEqual;{\mathrm{<figure-callout\; id="0"\; label="p"\; filenames="HDA0000470718350000021.png"\; state="\{\{state\}\}">p</figure-callout>}}_0\end{array}\right.$

Wherein M _bfor wheel braking moment, unit: kNm; C ^*for drg brake factors, unit: Nm/kPa; p ₀for braking initial delay, unit: MPa; P is braking pressure, unit: MPa;

Braking pressure model in described step c is the braking pressure model based on Method of Physical Modeling, and the dynamic differential equation of the braking pressure of this model is

$\left\{\begin{array}{cc}\frac{\mathrm{dP}}{\mathrm{dt}}=\frac{{\mathrm{KAP}}_1}{V}{\left(\frac{2}{K+1}\right)}^{\frac{1}{K-1}}\sqrt{\frac{2K}{K+1}{R}_0{T}_1}& P_2/P_1\&le;0.528\\ \frac{\mathrm{dP}}{\mathrm{dt}}=\frac{{\mathrm{KAP}}_1}{V}\sqrt{R_0{T}_1\frac{2}{K+1}[{\left(\frac{P_2}{P_1}\right)}^{\frac{2}{K}}-{\left(\frac{P_2}{P_1}\right)}^{\frac{K+1}{K}}]}& P_2/P_1\&GreaterEqual;0.528\end{array}\right.$

Wherein, V is gas chamber volume, is 1.06 × 10 ^-3m ³; A is air chamber sectional area, for: 1.26 × 10 ^-5m ²; R ₀for gas constant, be 287.1J/kgK; K is ratio of specific heat, is 1.4; T ₁for absolute temperature in air chamber, be 313K; P ₁, P ₂be respectively the pressure of air chamber entrance upstream and downstream.When supercharging, P ₁for fixed value 800kPa, P ₂for the pressure of compressed air brake cylinder; When decompression, P ₂for fixed value 100kPa, P ₁for compressed air brake cylinder pressure; When pressurize, kept the force value in a upper moment of local variable preservation.

Described wheel speed

wherein w ₀for initial angle acceleration/accel,

for wheel angular acceleration, R is radius of wheel;

Described slip rate

wherein v _{reference speed}for reference speed, v _wheelfor wheel speed.

Beneficial effect:

(1) cost is low, is easy to realize: only use the hardware simplicity such as common computer, capture card, ECU, V/F plate and computing machine just can realize the test of the ECU controller performance to ABS.

(2) can dynamic load model, adaptivity is good: this system a model database, can select voluntarily to load auto model, tire model, brake model and braking pressure model according to real needs, can adapt to different testing requirements.

(3) easy to use, test accuracy is high: this system only need be embedded into ECU in simulated environment by computer interface, thereby can simulate the running state of whole motor vehicle braking system, replace real vehicle test, realize cost low, test period is short, and the accuracy of test is high.

Brief description of the drawings

Fig. 1 is system hardware structure figure of the present invention

Fig. 2 is the inventive method diagram of circuit

Fig. 3 is the wheel speed/reference speed-time plot of test output

Fig. 4 is the slip rate-time plot of test output

Detailed description of the invention:

Below in conjunction with the drawings and specific embodiments, the present invention is further described.

As shown in Figure 1, this system comprises capture card, upper computer and V/F changer, the digital input interface of capture card is connected with the output interface of ECU to be measured, and the digital output interface of capture card is connected with the USB interface of upper computer, and the D/A interface of capture card is connected with the input interface of V/F changer; The output interface of V/F changer is connected with the input interface of ECU to be measured.

When work, the valve control signal that ECU to be measured produces is sent to the digital input interface of capture card through output interface; The digital output interface of capture card is sent to upper computer by this valve control signal and passes through USB interface; Upper computer is calculated wheel speed value and is converted to voltage signal by the analysis to this valve control signal and each model, is sent to V/F changer through the D/A of capture card interface; V/F changer is transformed to frequency signal by the voltage signal of capture card collection and is sent to the input interface of ECU to be measured, forms a closed loop system.

The ECU of real vehicle test passes is accessed after this system, first initialization vehicle parameter is set in upper computer, and vehicle parameter comprises carload lot, radius of wheel, number of gears, acceleration due to gravity constant, Automobile Maximum brake-pressure, the minimum brake-pressure of automobile, drg brake factors, Cars ' Moment of Inertia and braking rate of onset.Next arranges initialization road conditions parameter, selects a kind of condition of road surface.

In upper computer brake system model, select again a kind of auto model, tire model, brake model and braking pressure model.The auto model prestoring in system has single-wheel auto model, two-wheel vehicles model and four wheeler model; Tire model has theoretical model and empirical model, and empirical model is divided into again magic formula (H.B.Pacejka model) and bilinear model; Braking pressure model has the braking pressure model based on System Discrimination, Experiment Modeling and Method of Physical Modeling.

The vehicle dynamics modeling of the chapter 2 in " anti-lock vehicle braking control theory and application " that the method for building up of these models can be write referring to Lee fruit.

In upper computer according to each action object model of the simulation real vehicle of initialization vehicle parameter, road conditions parameter and loading, after processing by analysis, try to achieve brake-pressure, and then try to achieve wheel speed and reference speed, and wheel speed value is converted to voltage signal, be sent to V/F changer through the D/A of capture card interface; V/F changer is transformed to frequency signal by the voltage signal of capture card collection and is sent to the input interface of ECU to be measured, ECU to be measured produces valve control signal (" supercharging ", " decompression " or " pressurize ") after data analysis is processed, and is sent to the digital input interface of capture card through output interface; This valve control signal is sent to upper computer by the digital output interface of capture card.

In upper computer to wheel speed as shown in Figure 3 of output after reference speed and wheel speed analyzing and processing/with reference to Che Su ?time curve, and Hua Yi as shown in Figure 4 Shuai ?time curve.

If that this connecting system is the ECU of real vehicle test passes, according in wheel speed and reference speed curve, slip rate curve, the brake system model loading being assessed, if braking effect (braking time and slip rate size) meets the requirement of government test's standard, using the model of this loading as benchmark model; If do not meet accuracy requirement, reloading other brake system models continuation tests, until the measured braking effect that meets meets accuracy requirement.

Using the model that meets accuracy requirement as benchmark model, ECU connecting system to be measured is tested, identical initial condition (IC) and road conditions environment are set, the wheel speed curve and the slip rate curve that during by the ECU connecting system of the wheel speed curve obtaining and slip rate curve and real vehicle test passes, obtain contrast, and judge the performance quality of this ECU to be measured according to its degree of fitting.

Last under identical initial condition (IC) and road conditions environment, load this benchmark model other ECU to be tested are tested.

Based on the system of Fig. 1, the diagram of circuit of the method as shown in Figure 2, comprises model training process and actual measurement process:

Model training process comprises the following steps:

A: the ECU of real vehicle test passes is replaced to ECU connecting system to be measured;

B: initialization vehicle parameter and road conditions parameter; Described vehicle parameter comprises carload lot, radius of wheel, number of gears, acceleration due to gravity constant, Automobile Maximum brake-pressure, the minimum brake-pressure of automobile, drg brake factors, Cars ' Moment of Inertia and braking rate of onset; Initialization road conditions parameter refers in dry asphalt coating, moist earth road surface, snowy road surface and accumulated ice road surface selects a kind of condition of road surface, thereby determines peak adhesion coefficient μ _h; Slip rate corresponding adhesion value μ while being 100% _g; Adhesion value is μ _htime corresponding slip rate S _c, i.e. optimal slip ratio;

C: load a kind of auto model, tire model, brake model and braking pressure model in the analysis module of upper computer; Auto model is single-wheel auto model, two-wheel vehicles model or four wheeler model; Described tire model is theoretical model, magic formula model or bilinear model; Brake model is the linear model of simplifying; Braking pressure model is the braking pressure model based on System Discrimination modeling, Experiment Modeling or Method of Physical Modeling;

D: upper computer passes to braking rate of onset the ECU of real vehicle test passes;

E: produce valve control signal by the ECU of real vehicle test passes, described valve control signal comprises " 00 ", " 11 " and " 10 ", represents respectively " supercharging ", " decompression " and " pressurize ".；

F: the valve control signal that capture card collection is produced by the ECU of real vehicle test passes, sends upper computer to;

G: upper computer calculates wheel speed and the slip rate of this time braking according to auto model, tire model, brake model and the braking pressure model of valve control signal and step c loading;

H: upper computer shows wheel speed/reference speed-time curve and slip rate-time curve, judges whether this braking effect meets national standard, if the national standard of not meeting is returned to step c according to curve; Otherwise select the model this time loading as the benchmark model of testing;

Actual measurement process specifically comprises:

I: by ECU connecting system to be measured;

J: by step (b) initialization vehicle parameter and road conditions parameter, initial speed of braking is passed to ECU to be measured by upper computer;

K: produce valve control signal by ECU to be measured;

L: the valve control signal that capture card collection is produced by ECU not to be measured, sends upper computer to;

M: upper computer calculates wheel speed and the slip rate of this time braking according to the benchmark model of valve control signal and loading, according to braking rate of onset v ₀, automobile body deceleration

with by formula

obtain reference speed;

N: upper computer shows wheel speed/reference speed-time curve and slip rate-time curve, and the curve that the ECU of the curve that this is obtained and real vehicle test passes calculates by key model contrasts, judges the performance without the ECU of real vehicle test.

The ECU of certain automobile of researching and developing taking certain vehicle electronics Co., Ltd, as example, tests the controller performance of the ECU testing through real vehicle test passes with without real vehicle respectively.

First the controller performance of the ECU through real vehicle test passes is tested, ECU is accessed to this test macro and gather to upper computer by the DI interface of capture card.In upper computer test software, first initialization arranges the vehicle parameters (it is 70km/h that initial speed of braking is set) such as carload lot, number of gears, Cars ' Moment of Inertia and initial speed of braking here, and select single dry asphalt coating (optimal slip ratio is 17%) as the road conditions parameter setting and be passed in model-container, then in container model, load single-wheel auto model, bilinearity tire model, linear brake model and the braking pressure model based on Method of Physical Modeling, the concrete methods of realizing of these models is:

Auto model is selected single-wheel auto model, and its equation of motion is

$I\stackrel{\&CenterDot;}{w}=\mathrm{\&mu;NR}-M_b$

Wherein, I is Cars ' Moment of Inertia, unit: kgm ²; for wheel angular acceleration, unit: rad/s ²; R is radius of wheel, unit: m; μ is adhesion value; N is the normal reaction of wheel to ground; M _bfor wheel braking moment, unit: Nm;

Tire model is selected bilinearity tire model, and the pass between its adhesion value μ and slip rate S is

$\left\{\begin{array}{cc}\mathrm{\&mu;}=\frac{{\mathrm{\&mu;}}_h}{{\mathrm{\&mu;}}_g}S& S\&le;S_c\\ \mathrm{\&mu;}=\frac{{\mathrm{\&mu;}}_h-{\mathrm{\&mu;}}_g{S}_c}{1-S_c}-\frac{{\mathrm{\&mu;}}_h-{\mathrm{\&mu;}}_g}{1-S_c}S& S>S_c\end{array}\right.$

Wherein, μ _hfor peak adhesion coefficient; μ _gcorresponding adhesion value while being 100% for slip rate; S _cfor adhesion value is μ _htime corresponding slip rate, i.e. optimal slip ratio; μ _h, μ _g, S _cthe condition of road surface of selecting according to initialization road conditions parameter is determined;

Brake model is selected the linear model of simplifying, and acts on lock torque on wheel and the mathematical relation of brake-pressure to be

$\left\{\begin{array}{cc}{M}_b=0& p<p_0\\ M_b=C^{*}(p-p_0)& p\&GreaterEqual;{\mathrm{<figure-callout\; id="0"\; label="p"\; filenames="HDA0000470718350000021.png"\; state="\{\{state\}\}">p</figure-callout>}}_0\end{array}\right.$

Wherein M _bfor wheel braking moment, unit: kNm; C ^*for drg brake factors, unit: Nm/kPa; p ₀for braking initial delay, unit: MPa; P is braking pressure, unit: MPa;

Braking pressure model is the braking pressure model based on Method of Physical Modeling, and the dynamic differential equation of the braking pressure of this model is

$\left\{\begin{array}{cc}\frac{\mathrm{dP}}{\mathrm{dt}}=\frac{{\mathrm{KAP}}_1}{V}{\left(\frac{2}{K+1}\right)}^{\frac{1}{K-1}}\sqrt{\frac{2K}{K+1}{R}_0{T}_1}& P_2/P_1\&le;0.528\\ \frac{\mathrm{dP}}{\mathrm{dt}}=\frac{{\mathrm{KAP}}_1}{V}\sqrt{R_0{T}_1\frac{2}{K+1}[{\left(\frac{P_2}{P_1}\right)}^{\frac{2}{K}}-{\left(\frac{P_2}{P_1}\right)}^{\frac{K+1}{K}}]}& P_2/P_1\&GreaterEqual;0.528\end{array}\right.$

Wherein, V is gas chamber volume, is 1.06 × 10 ^-3m ³; A is air chamber sectional area, for: 1.26 × 10 ^-5m ²; R ₀for gas constant, be 287.1J/kgK; K is ratio of specific heat, is 1.4; T ₁for absolute temperature in air chamber, be 313K; P ₁, P ₂be respectively the pressure of air chamber entrance upstream and downstream.

This model is divided into supercharging, decompression and three kinds of situations of pressurize: 1. when supercharging, and P ₁for fixed value 800kPa, P ₂for the pressure of compressed air brake cylinder.2. while decompression, P ₂for fixed value 100kPa, P ₁for compressed air brake cylinder pressure.3. when pressurize, kept the force value in the upper moment that local variable preserves.

The test macro test that brings into operation after loading completes: the initial speed of braking 70km/h of given ECU, ECU produces certain group valve control signal of " 00 " " 10 " or " 11 "; Capture card gathers this valve control signal, and sends it to upper computer; Upper computer judges that valve control signal is for " supercharging ", " pressurize " or " decompression "; Then according to braking pressure model, selection pressure is asked for formula and is tried to achieve brake-pressure, and after processing, brake model obtains acting on the lock torque on tire, auto model obtains and calculates this time angular acceleration of braking according to this lock torque and initialized road conditions parameter again, and then according to formula

wherein for wheel angular acceleration, R is radius of wheel, tries to achieve wheel speed now; Wheel speed signal is transformed into voltage signal through data interface module; Capture card collects the voltage signal that upper computer sends, and sends it to V/F changer; V/F changer converts voltage signal to the frequency signal that becomes certain relation with voltage, and sends it to ECU; ECU judges and delivery valve control signal according to the frequency signal of input, forms a closed loop test system.Meanwhile, according to braking rate of onset v ₀, automobile body deceleration

[determined by Slope Method, concrete visible document " anti-blocking brake system of automobile reference speed is determined method "] by formula can obtain reference speed, because the actual speed of car body cannot obtain, so with reference speed approximate representation body speed of vehicle.Finally to obtaining slip rate [slip rate after reference speed and wheel speed analyzing and processing

] change curve.In this braking procedure, test figures meeting autostore is to data bank, so that follow-up test analysis.

After braking procedure finishes, click result the Show Button obtain test test results as shown in Figure 3 and Figure 4, wherein Fig. 3 be wheel speed/with reference to Che Su ?time plot, Fig. 4 be Hua Yi Shuai ?time curve.Can be found out under ABS effect by Fig. 3 and Fig. 4, wheel speed can be followed the speed of a motor vehicle preferably, slip rate remains between 15%～25%, near optimal slip ratio 17%, change, illustrate and in whole braking procedure, take full advantage of the adhesion value that ground provides, and in 15s, complete braking, meet the test criteria that China's performance of ABS detects.And when braking wheel there is not the situation of complete locking, actv. has prevented the locking of wheel, illustrate that the ECU testing is qualified, and then shows for qualified ECU, this test macro is can its controller performance be tested accurately and be judged.Illustrate that the auto model, tire model, brake model and the braking pressure model that in this test, load can meet the accuracy requirement of test, therefore using these models as benchmark model, to testing without the ECU of real vehicle test simultaneously.

The said firm is produced to ECU to be tested and access this test macro dynamic load benchmark model, under identical initial condition (IC) and road conditions environment, test.Result shows, for the ECU without real vehicle test, this system also can be tested the controller performance of ECU accurately, and then judges that can ABS realize ABS (Anti-lock Braking System).So the test method of the ECU of the ABS that the present invention proposes and computer system can realize the test of the controller performance to ECU accurately, and it is low to realize cost, adaptivity is good, can before ECU dispatches from the factory, detect on a large scale, and work efficiency is high.

Claims (7)

1. a system for the electronic control unit performance in measuring air pressure type ABS, is characterized in that, comprises capture card, upper computer and V/F changer;

The digital input interface of capture card connects the output interface of ECU to be measured, and the digital output interface of capture card is connected with upper computer, passes to upper computer for the valve control signal that ECU to be measured is produced;

The D/A mouth of capture card is connected with the input end of V/F changer, and the mouth of V/F changer is connected with the input interface of ECU to be measured, passes to ECU for the wheel speed signal that upper computer is produced.

2. the system of the electronic control unit performance in measuring air pressure type ABS according to claim 1, is characterized in that, described upper computer comprises auto model, tire model, brake model and braking pressure model database.

3. a method for the electronic control unit performance in measuring air pressure type ABS, adopts the system of the electronic control unit performance in measuring air pressure type ABS claimed in claim 2, it is characterized in that, comprising:

Model training process and actual measurement process;

Described model training process comprises the following steps:

A: the ECU of real vehicle test passes is replaced to ECU connecting system to be measured;

B: initialization vehicle parameter and road conditions parameter; Described vehicle parameter comprises carload lot, radius of wheel, number of gears, acceleration due to gravity constant, Automobile Maximum brake-pressure, the minimum brake-pressure of automobile, drg brake factors, Cars ' Moment of Inertia and braking rate of onset; Initialization road conditions parameter refers to selects a kind of condition of road surface, thereby determines peak adhesion coefficient μ _h; Slip rate corresponding adhesion value μ while being 100% _g; Adhesion value is μ _htime corresponding slip rate S _c, S _cit is optimal slip ratio;

C: load one group of auto model, tire model, brake model and braking pressure model in the analysis module of upper computer;

D: upper computer passes to braking rate of onset the ECU of real vehicle test passes;

E: produce valve control signal by the ECU of real vehicle test passes, described valve control signal comprises " 00 ", " 11 " and " 10 ", represents respectively " supercharging ", " decompression " and " pressurize ";

F: the valve control signal that capture card collection is produced by the ECU of real vehicle test passes, sends upper computer to;

G: upper computer calculates wheel speed and the slip rate of this time braking according to auto model, tire model, brake model and the braking pressure model of valve control signal and step c loading;

H: upper computer shows wheel speed/reference speed-time curve and slip rate-time curve, judges whether this braking effect meets national standard, if the national standard of not meeting is returned to step c according to curve; Otherwise select the model this time loading as the benchmark model of testing;

Described actual measurement process specifically comprises:

I: by ECU connecting system to be measured;

J: by step b initialization vehicle parameter and road conditions parameter, initial speed of braking is passed to ECU to be measured by upper computer;

K: produce valve control signal by ECU to be measured;

L: the valve control signal that capture card collection is produced by ECU to be measured, sends upper computer to;

M: upper computer calculates wheel speed and the slip rate of this time braking according to the benchmark model of valve control signal and loading, according to braking rate of onset v ₀, automobile body deceleration

and formula

obtain reference speed;

N: upper computer shows wheel speed/reference speed-time curve and slip rate-time curve, and the curve that the ECU of the curve that this is obtained and real vehicle test passes obtains by benchmark model contrasts, judges the performance without the ECU of real vehicle test.

4. the method for the electronic control unit performance in measuring air pressure type ABS according to claim 3, is characterized in that, the condition of road surface in described step b is dry asphalt coating, moist earth road surface, snowy road surface or accumulated ice road surface.

5. the method for the electronic control unit performance in measuring air pressure type ABS according to claim 3, is characterized in that, described auto model is single-wheel auto model, two-wheel vehicles model or four wheeler model;

Described tire model is theoretical model, magic formula model or bilinear model;

Described brake model is the linear model of simplifying;

Described braking pressure model is the braking pressure model based on System Discrimination modeling, Experiment Modeling or Method of Physical Modeling.

6. the method for the electronic control unit performance in measuring air pressure type ABS according to claim 3, is characterized in that,

Auto model in described step c is single-wheel auto model, and its equation of motion is

$I\stackrel{\&CenterDot;}{w}=\mathrm{\&mu;NR}-M_b$

Wherein, I is Cars ' Moment of Inertia, unit: kgm ²; for wheel angular acceleration, unit: rad/s ²; R is radius of wheel, unit: m; μ is adhesion value; N is the normal reaction of wheel to ground; M _bfor wheel braking moment, unit: Nm;

Tire model in described step c is bilinear model: the pass between adhesion value μ and slip rate S is

$\left\{\begin{array}{cc}\mathrm{\&mu;}=\frac{{\mathrm{\&mu;}}_h}{{\mathrm{\&mu;}}_g}S& S\&le;S_c\\ \mathrm{\&mu;}=\frac{{\mathrm{\&mu;}}_h-{\mathrm{\&mu;}}_g{S}_c}{1-S_c}-\frac{{\mathrm{\&mu;}}_h-{\mathrm{\&mu;}}_g}{1-S_c}S& S>S_c\end{array}\right.$

Wherein, μ _hfor peak adhesion coefficient; μ _gcorresponding adhesion value while being 100% for slip rate; S _cfor adhesion value is μ _htime corresponding slip rate, i.e. optimal slip ratio;

Brake model in described step c is the linear model of simplifying: acting on lock torque on wheel and the mathematical relation of brake-pressure is

$\left\{\begin{array}{cc}{M}_b=0& p<p_0\\ M_b=C^{*}(p-p_0)& p\&GreaterEqual;p_0\end{array}\right.$

Wherein M _bfor wheel braking moment, unit: kNm; C ^*for drg brake factors, unit: Nm/kPa; p ₀for braking initial delay, unit: MPa; P is braking pressure, unit: MPa;

Braking pressure model in described step c is the braking pressure model based on Method of Physical Modeling, and the dynamic differential equation of the braking pressure of this model is

$\left\{\begin{array}{cc}\frac{\mathrm{dP}}{\mathrm{dt}}=\frac{{\mathrm{KAP}}_1}{V}{\left(\frac{2}{K+1}\right)}^{\frac{1}{K-1}}\sqrt{\frac{2K}{K+1}{R}_0{T}_1}& P_2/P_1\&le;0.528\\ \frac{\mathrm{dP}}{\mathrm{dt}}=\frac{{\mathrm{KAP}}_1}{V}\sqrt{R_0{T}_1\frac{2}{K+1}[{\left(\frac{P_2}{P_1}\right)}^{\frac{2}{K}}-{\left(\frac{P_2}{P_1}\right)}^{\frac{K+1}{K}}]}& P_2/P_1\&GreaterEqual;0.528\end{array}\right.$

Wherein, V is gas chamber volume, is 1.06 × 10 ^-3m ³; A is air chamber sectional area, for: 1.26 × 10 ^-5m ²; R ₀for gas constant, be 287.1J/kgK; K is ratio of specific heat, is 1.4; T ₁for absolute temperature in air chamber, be 313K; P ₁, P ₂be respectively the pressure of air chamber entrance upstream and downstream; When supercharging, P ₁for fixed value 800kPa, P ₂for the pressure of compressed air brake cylinder; When decompression, P ₂for fixed value 100kPa, P ₁for compressed air brake cylinder pressure; When pressurize, kept the force value in a upper moment of local variable preservation.

7. the method for the electronic control unit performance in a kind of measuring air pressure type ABS according to claim 4, is characterized in that,

Described wheel speed wherein w ₀for initial angle acceleration/accel,

for wheel angular acceleration, R is radius of wheel;

Described slip rate wherein v _{reference speed}for reference speed, v _wheelfor wheel speed.

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