CN101767577A - Wheel vertical pressure identification method for automotive electronic stabilization control system - Google Patents

Abstract

A wheel vertical pressure identification method for an automotive electronic stabilization control system is characterized in that a wheel vertical pressure identification module is arranged in an automotive electronic stabilization controller, wherein the input end of the wheel vertical pressure identification module is connected with the longitudinal accelerator and the lateral accelerator of the automotive electronic stabilization control system, and the output end thereof is connected with a dynamic controller; based on the inherent complete total mass, wheel tread, wheel base, the distance from the center of mass to the front axle and the rear axle, and the longitudinal and lateral accelerated speeds of the longitudinal accelerator and the lateral accelerator, the vertical pressure of each wheel of the automobile can be calculated with corresponding equation. The positive pressure value of each wheel is input into the automotive electronic stabilization controller, thus realizing the electrically stable control and rolling-preventing control of the automotive. The positive effect of the invention is that the problem that the positive pressure of each wheel of the automotive can not be measured. The invention makes the automotive electronic stabilization controller more accurately control the slip rate and braking force of the wheel, greatly improves the performance of the electronic stabilization control system, and also can make the automotive electronic stabilization controller reach the rolling-preventing function for the automotive.

Description

The wheel vertical pressure identification method that is used for automobile electron stabilization control system

Technical field

The invention belongs to automobile technical field, be specifically related to influence a kind of indirectly the measure method of automobile electron stabilization controller the wheel vertical pressure of wheel slip and brake-power control effect.

Background technology

When automobile electron stabilization control system is in limit driving cycle at automobile,, keep the riding stability of automobile at limit driving cycle by regulating each wheel drive power or braking force motion state of automobile to regulate.It is the important measures that improve vehicle handling stability, improve vehicle active safety.This system is used widely in developed country at present, and states such as the U.S., Australia have formulated mandatory rules of law and required all automobiles below 4.5 tons must install electronic stabilizing control system additional.As seen this system gains public acceptance to the obvious effect that improves vehicle active safety.The automobile electron stabilization controller system will depend on wheel slip and adhesion to road surface characteristic to the adjusting of propulsive effort and braking force, and the two particularly the latter is very strong to the vertical pressure dependence between wheel and the road surface, and in vehicle traveling process, wheel vertical pressure but is constantly to change.But because obtaining in real time of vehicle traveling process wheel vertical pressure is the insoluble problem of automobile technical field always, therefore do not consider generally in present automobile electron stabilization control system that wheel vertical pressure changes the influence to the braking torque expected value, and wheel vertical pressure is treated as a static constant.This makes the control accuracy of automobile electron stabilization control system not high, causes automobile in the electronic stabilizing control system control process, and fluctuation is big, even can cause the chaufeur anxiety.In addition automobile in limit driving process, occur the critical conditions of overturning also and the vertical pressure between road surface and the wheel closely related, when being zero when the vertical pressure between single wheel and the road surface, automobile promptly is in the critical conditions of tumbling.If can obtain wheel and ground-surface vertical pressure in real time, then can be before automobile reaches the critical conditions of tumbling regulate vehicle condition by electronic stabilizing control system, prevent that automobile from tumbling.

Summary of the invention

The purpose of this invention is to provide a kind of wheel vertical pressure identification method that is used for automobile electron stabilization control system, can obtain each wheel of automobile and ground-surface vertical pressure, solve automobile and respectively take turns the difficult problem that vertical pressure can't be measured by this method.

The inventive method is an input end to be set be connected with the lateral acceleration sensor with the longitudinal acceleration of automobile electron stabilization controller in automobile electron stabilization control system, the wheel vertical pressure identification module that mouth is connected with the automobile electron stabilization controller, this identification module is based on the intrinsic parameter of car body: complete vehicle quality, wheelspan, wheelbase, the distance of automobile barycenter to front axle and automobile barycenter to rear axle, instantaneous longitudinal acceleration and lateral acceleration according to longitudinal acceleration sensor and the input of lateral acceleration sensor signal, calculate the vertical pressure that can obtain each wheel of automobile by following functional expression (1)-(4), will calculate the wheel vertical pressure that obtains again and be input to of the electronic stability control of electronic stability controller with better realization automobile.

$F_{z1}=\frac{{\mathrm{ma}}_x{h}_{g}B+{\mathrm{mgl}}_{r}B-{\mathrm{ma}}_y{\mathrm{<figure-callout\; id="2"\; label="h\; g\; l"\; filenames="H2009100664105E0000011.png"\; state="\{\{state\}\}">h</figure-callout>}}_{g}l}{2\mathrm{Bl}}---\left(1\right)$

${\mathrm{<figure-callout\; id="3"\; label="F\; z"\; filenames="H2009100664105E0000012.png"\; state="\{\{state\}\}">F</figure-callout>}}_z=\frac{m}{l}({\mathrm{gl}}_r+a_x{h}_g)-F_{z1}---\left(2\right)$

$F_{z2}=\frac{\mathrm{mg}}{2}-F_{z3}---\left(3\right)$

$F_{z4}=\frac{\mathrm{mg}}{2}-F_{z1}---\left(4\right)$

F in the formula _Z1F _Z2F _Z3F _Z4Be each wheel vertical pressure of automobile, F _Z1F _Z2F _Z3F _Z4Represent the near front wheel, left rear wheel, off front wheel, off hind wheel respectively.M is a car mass, and g is an acceleration due to gravity, and l is a vehicle wheel base, l _rFor the automobile barycenter apart from the rear axle distance, B is a wheelspan, h _gFor the automobile barycenter apart from floor level, a _xBe automobile longitudinal acceleration, a _yBe the automobile side angle acceleration/accel.

If the electronic stabilizing control system of car equipment does not install longitudinal acceleration sensor additional, that electronic stability controller must calculate the longitudinal acceleration of automobile by the wheel speed of each wheel.The required longitudinal acceleration signal of automotive wheel vertical pressure identification module this moment can be imported by the electronic stability controller.

The invention has the beneficial effects as follows: realizing obtaining in real time of vertical pressure between each wheel of automobile and the ground under the situation that need not additionally install special survey sensor additional.Improve the control accuracy of automobile electron stabilization controller greatly to wheel slip, propulsive effort or braking force, make it regulate each wheel drive force of automobile or braking force during in dangerous operating mode more accurately at running car, the stability that keeps automobile, significantly promote the controller performance of automobile electron stabilization device, and make electronic stabilizing control system expand to the automotive anti-rolling function.

Description of drawings

Fig. 1 is a stressed scheme drawing in the vehicle traveling process.

To be the present invention form scheme drawing by the system of the automotive wheel vertical pressure identification method of longitudinal acceleration sensor to Fig. 2.

To be the present invention form scheme drawing by the system of the automotive wheel vertical pressure identification method of longitudinal acceleration sensor to Fig. 3.

Fig. 4 is the program flow chart of automotive wheel vertical pressure identification method of the present invention

The specific embodiment

Below in conjunction with accompanying drawing the inventive method is described in further detail.

Consult Fig. 2, Fig. 3, Fig. 4, the wheel vertical pressure identification module 3 that longitudinal acceleration sensor 1 is connected with lateral acceleration sensor 2, mouth is connected with electronic stability controller 4 of an input end and automobile is set in automobile electron stabilization control system.This wheel positive pressure identification module 3 based on car body complete vehicle quality m, wheelspan B shown in Figure 1, wheelbase l, automobile barycenter to rear axle apart from l _r, according to instantaneous longitudinal acceleration a vertical and input of lateral acceleration sensor signal _x, lateral acceleration a _y, press following functional expression:

$F_{z1}=\frac{{\mathrm{ma}}_x{h}_{g}B+{\mathrm{mgl}}_{r}B-{\mathrm{ma}}_y{\mathrm{<figure-callout\; id="2"\; label="h\; g\; l"\; filenames="H2009100664105E0000011.png"\; state="\{\{state\}\}">h</figure-callout>}}_{g}l}{2\mathrm{Bl}}---\left(1\right)$

${\mathrm{<figure-callout\; id="3"\; label="F\; z"\; filenames="H2009100664105E0000012.png"\; state="\{\{state\}\}">F</figure-callout>}}_z=\frac{m}{l}({\mathrm{gl}}_r+a_x{h}_g)-F_{z1}---\left(2\right)$

$F_{z2}=\frac{\mathrm{mg}}{2}-F_{z3}---\left(3\right)$

$F_{z4}=\frac{\mathrm{mg}}{2}-F_{z1}---\left(4\right)$

Calculating can obtain automobile and respectively take turns the vertical pressure value, F in the formula _Z1F _Z2F _Z3F _Z4Represent the vertical pressure of the near front wheel, left rear wheel, off front wheel, off hind wheel respectively.To calculate each the wheel positive pressure value that obtains again and be input to the electronic stability controller 4 shown in Fig. 2, Fig. 3.Electronic stability controller 4 is regulated slip rate and the propulsive effort or the braking force of each wheel 5,6,7,8 of the automobile shown in Fig. 2, Fig. 3 according to the wheel vertical pressure value of input, thereby keeps the steady state of motion of automobile.This automobile electron stabilization control system is under additive incrementation sensor situation not, obtained each wheel vertical pressure of automobile by a kind of straightforward procedure, make automobile electron stabilization control system more accurate to the adjusting of wheel slip and propulsive effort and braking force, system's control is more steady, and makes automobile electron stabilization control system can expand to the automotive anti-rolling function.

Above-mentioned functional expression (1)-(4) 1 obtain by the following derivation of equation with reference to the accompanying drawings:

The equilibrium equation of automobile vertical force is:

F _z1+F _z2+F _z3+F _z4＝mg (5)

Automobile 1 is taken turns and 3 is taken turns earth point line power taking square balance and get:

(F _z1+F _z3)l-ma _xh _g-m _gl _r＝0 (6)

Taking turns earth point and 3 to 1 takes turns the line power taking square balance of earth point and gets:

$(F_{z1}+F_{z2})B+{\mathrm{ma}}_{y}h-\mathrm{<figure-callout\; id="2"\; label="mg\; B"\; filenames="H2009100664105E0000011.png"\; state="\{\{state\}\}">mg</figure-callout>}\frac{B}{}\frac{}{2}=0---\left(7\right)$

The modern automobile complete vehicle weight becomes left-right symmetric to distribute.Therefore in vehicle traveling process, consider the mass transfer factor interior, the vertical load sum of two wheels must be half of complete vehicle quality on the automobile diagonal line.Therefore have:

$F_{z3}+F_{z2}=\frac{\mathrm{mg}}{2}---\left(8\right)$

$F_{z1}+F_{z4}=\frac{\mathrm{mg}}{2}---\left(9\right)$

Get by formula (8):

$F_{z2}=\frac{\mathrm{mg}}{2}-F_{z3}---\left(10\right)$

Wushu (10) substitution formula (7):

$(F_{z1}+\frac{\mathrm{mg}}{2}-F_{z3})B+{\mathrm{ma}}_{y}h-\mathrm{<figure-callout\; id="2"\; label="mg\; B"\; filenames="H2009100664105E0000011.png"\; state="\{\{state\}\}">mg</figure-callout>}\frac{B}{}\frac{}{2}=0$

Put in order:

${\mathrm{<figure-callout\; id="3"\; label="F\; z"\; filenames="H2009100664105E0000012.png"\; state="\{\{state\}\}">F</figure-callout>}}_z=F_{z1}+\frac{{\mathrm{ma}}_y{h}_g}{B}---\left(11\right)$

(11) are got for people (6):

$({2F}_{z1}+\frac{{\mathrm{ma}}_y{h}_g}{B})l-{\mathrm{ma}}_x{h}_g-m_g{l}_r=0$

Put in order:

$F_{z1}=\frac{{\mathrm{ma}}_x{h}_{g}B+{\mathrm{mgl}}_{r}B-{\mathrm{ma}}_y{\mathrm{<figure-callout\; id="2"\; label="h\; g\; l"\; filenames="H2009100664105E0000011.png"\; state="\{\{state\}\}">h</figure-callout>}}_{g}l}{2\mathrm{Bl}}---\left(12\right)$

Can get by formula (12) and formula (8), (9):

${\mathrm{<figure-callout\; id="3"\; label="F\; z"\; filenames="H2009100664105E0000012.png"\; state="\{\{state\}\}">F</figure-callout>}}_z=\frac{m}{l}({\mathrm{gl}}_r+a_x{h}_g)-F_{z1}---\left(13\right)$

$F_{z2}=\frac{\mathrm{mg}}{2}-F_{z3}---\left(14\right)$

$F_{z4}=\frac{\mathrm{mg}}{2}-F_{z1}---\left(15\right)$

The longitudinal acceleration of automobile and lateral acceleration are easy to detect, on the automobile of equipment electronic stabilizing control system (ESP), the lateral acceleration sensor is housed all, all be equipped with longitudinal acceleration sensor on the four-wheel drive car of equipment electronic stabilizing control system, be equipped with longitudinal acceleration sensor on the part two-wheel drive automobile.In not equipping the longitudinal acceleration sensor electric stabilizing system, also all adopt the wheel speed sensors of four wheels to calculate the speed of a motor vehicle and longitudinal acceleration.Owing to the reduction of acceleration pick-up cost, the modern automobile electronic stabilizing control system more and more directly measures the longitudinal acceleration of automobile by longitudinal acceleration sensor in addition.No matter whether longitudinal acceleration sensor, longitudinal acceleration that the inventive method is required and lateral acceleration sensor being arranged all is known signal in existing electronic stabilizing control system.Lateral acceleration directly measures when implementing the inventive method, and longitudinal acceleration has two kinds of methods to obtain: the one, directly measure by installing longitudinal acceleration sensor additional; Another kind method is that the longitudinal acceleration that is got by the calculating of automobile electron stabilization controller exports the wheel vertical pressure computing module to.

Claims (1)

1. the wheel vertical pressure identification method that is used for automobile electron stabilization control system, it is characterized in that: an input end is set in automobile electron stabilization control system is connected with the lateral acceleration sensor with the vertical of automobile, the wheel vertical pressure identification module that mouth is connected with the automobile electron stabilization controller, this wheel vertical pressure identification module is based on the intrinsic complete vehicle quality of car body, wheelspan, wheelbase, distance parameter and the longitudinal acceleration of automobile barycenter to front axle and automobile barycenter to rear axle, the longitudinal acceleration and the lateral acceleration value of the input of lateral acceleration sensor are utilized following formula to calculate and are respectively taken turns vertical pressure in the vehicle traveling process;

$F_{z1}=\frac{{\mathrm{ma}}_x{h}_{g}B+\mathrm{mg}{l}_{r}B-{\mathrm{ma}}_y{h}_{g}l}{2\mathrm{Bl}}---\left(1\right)$

$F_{z3}=\frac{m}{l}({\mathrm{gl}}_r+a_x{h}_g)-F_{z1}---\left(2\right)$

$F_{z2}=\frac{\mathrm{mg}}{2}-F_{z3}---\left(3\right)$

$F_{z4}=\frac{\mathrm{mg}}{2}-F_{z1}---\left(4\right)$

F in the formula _Z1F _Z2F _Z3F _Z4Be each wheel vertical pressure of automobile, F _Z1F _Z2F _Z3F _Z4Represent the near front wheel, left rear wheel, off front wheel, off hind wheel respectively.M is a car mass, and g is an acceleration due to gravity, and l is a vehicle wheel base, l _rFor the automobile barycenter apart from the rear axle distance, B is a wheelspan, h _gFor the automobile barycenter apart from floor level, a _xBe automobile longitudinal acceleration, a _yBe the automobile side angle acceleration/accel;

In the control system that longitudinal acceleration sensor is not installed, longitudinal acceleration signal is taken in the automobile electron stabilization controller and is calculated and the longitudinal acceleration signal of acquisition by wheel speed.

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