WO2006058702A1

WO2006058702A1 - Device and method for stabilising a motor vehicle exposed to crosswind

Info

Publication number: WO2006058702A1
Application number: PCT/EP2005/012738
Authority: WO
Inventors: Dieter Ammon Ammon; Jens Kalkkuhl; Carsten Knöppel; Martin Moser; Magnus Rau; Reinhold Schneckenburger; Avshalom Suissa; Christian Urban
Original assignee: Daimlerchrysler Ag
Priority date: 2004-12-01
Filing date: 2005-11-29
Publication date: 2006-06-08
Also published as: DE102004057928A1

Abstract

The invention relates to a device and method for stabilising a motor vehicle exposed to crosswind by means of a device (12) for evaluating a crosswind force value to which influence the motor vehicle (10) is exposed and a stabilising device (13) which influences the motor vehicle (10) transversal dynamics and to which the evaluated crosswind force value is transmitted for compensating the crosswind influence exerted on the motor vehicle (10). The inventive stabilising device (13) is used for modifying wheel contact forces (F11,, ..., F14) acting on the motor vehicle (10) wheels (27a,..., 27d), wherein said stabilising device (13) modifies the wheel contact forces (F11,, ..., F14) according to the crosswind force value in such a way that the influence exerted by the crosswind is compensated.

Description

Device and method for crosswind stabilization of a vehicle

The invention relates to an apparatus and method for crosswind stabilization of a vehicle comprising an estimator for estimating a crosswinds magnitude which reflects a crosswind influence exerted on the vehicle, and a stabilizer for influencing the transverse dynamics of the vehicle which estimates the estimated crosswinds size for compensation supplied to the vehicle exerted crosswind influence.

Such a device for minimizing the crosswind influence on the driving behavior of a vehicle is evident from DE 41 27 725 Al. The known device comprises a pressure measuring device, which is arranged for quantitatively detecting a side wind influence exerted on the vehicle in the side region of the outer skin of the vehicle body. The provided by the pressure measuring device pressure measurement signals are arranged in the vehicle, a digital computer and an actuator having Lenkwinkel- adjustment device supplied depending on the supplied pressure measuring signals adjustable to steerable wheels of the vehicle steering angle modified such that caused due to the crosswind influence yaw angle change of Vehicle is compensated.

Such a steering angle adjusting device, as is required a priori for the realization of the known device, is due to cost reasons or reasons of reliability in general not available.

It is therefore an object of the present invention, a device or a method of the type mentioned in such a way that a cost-efficient and reliable control of the transverse dynamics of the vehicle to compensate for the force exerted on the vehicle crosswind influence is made possible.

This object is achieved according to the features of claim 1 or of claim 17.

The lateral wind stabilization apparatus of a vehicle further comprises, in addition to an estimator of side wind magnitude estimation representing a side wind exerted on the vehicle, a stabilizer provided for influencing the lateral dynamics of the vehicle to which the estimated side wind magnitude is supplied to compensate for the crosswind influence exerted on the vehicle , According to the invention, the stabilization device is designed to modify wheel contact forces acting on the wheels of the vehicle, the stabilization device modifying the wheel contact forces as a function of the crosswind size in such a way that the side wind influence exerted on the vehicle is compensated or at least considerably reduced. The modification of the wheel contact forces makes it possible to carry out a particularly robust and reliable manipulation of the transverse dynamics of the vehicle.

The stabilization device can then be, in particular, an active suspension (active body control - ABC, Active Hydropneumatics or active stabilizers) which is available as standard and which, depending on the road condition and the driving behavior of the driver, damps travel-related movements of the vehicle Vehicle construction in the sense of increasing the Driving comfort and driving safety by appropriate driver-independent modification of RadaufStandskräfte makes.

Advantageous embodiments of the device according to the invention will become apparent from the dependent claims.

Advantageously, the estimation device estimates the crosswinds size based on a vehicle model into which a lateral acceleration variable, which acts on a vehicle. Transverse acceleration describes, and / or a yaw rate, which describes a yaw rate of the vehicle about an axis oriented in the vehicle vertical axis of rotation is received. Correspondingly, a mounting of pressure sensors in the region of the outer skin of the vehicle body which is to be regarded as problematic from an aesthetic point of view for detecting the crosswind influence can be avoided.

In addition, the variables used to estimate the crosswinds allow, in addition to a possible influence of crosswinds, to estimate and, if necessary, to compensate for a lateral force influence acting on the vehicle as a result of a bank inclination on the roadway.

The vehicle model is, in particular, a linear single-track model that is easy to evaluate and in most cases sufficient to describe the lateral dynamics of the vehicle (see "Adam Zomotor, Chassis Technology: Handling", 1st Edition, Vogel-Fachbuch, p. However, although any other vehicle model may be provided that describes the lateral dynamics of the vehicle in a sufficient manner.

In order to additionally increase the accuracy with respect to the estimation of crosswind size, there is the possibility that the vehicle model takes into account, in addition to the above-mentioned variables, the lateral dynamic response of the vehicle to a modification of the wheel contact forces. Furthermore, it is advantageous if the transverse acceleration quantity is provided in the form of a lateral acceleration signal by means of a lateral acceleration sensor and / or if the yaw rate quantity is provided in the form of a yaw rate signal by means of a yaw rate sensor. Since such sensors in connection with an existing system in the vehicle for yaw rate control, such as an Electronic Stability Program (ESP), usually anyway available, their shared use allows a particularly cost-effective implementation of the device according to the invention.

If no such sensors are available, it is also conceivable to determine the two variables on the basis of a longitudinal speed variable which describes a vehicle speed present in the vehicle longitudinal direction, and / or a steering wheel angle which describes a steering angle which can be set on steerable wheels of the vehicle. The longitudinal speed magnitude is obtained, for example, by evaluating wheel speed signals provided by wheel speed sensors associated with the wheels of the vehicle. The same applies to the steering angle variable, which is provided in the form of a steering angle signal by means of a steering angle sensor, which detects the steering angle set on steerable wheels of the vehicle.

In summary, the estimation device therefore estimates based on sensory or model-based determined driving dynamics variables using a suitable vehicle model, in particular a linear single-track model for describing the lateral dynamics of the vehicle, for example the shape

Vy = a _y, v _x _meS8 -Ψ--g-Φ (1.1)

Ψ

(1.2) a lateral wind amount representing a side wind influence exerted on the vehicle. The side wind size can be quantified in mathematically unambiguous manner, inter alia in the form of a side wind force magnitude S _{w /} which describes a cross wind force exerted on the vehicle due to the crosswind, whereby any other side wind force factors reflecting the crosswind influence can be determined in addition to or as an alternative to the cross wind force size S ". By way of example, the driving dynamics quantities entering the determination equations (1.1) and (1.2) are the lateral acceleration variable detected by means of the lateral acceleration sensor and the yaw rate parameter detected by the yaw rate sensor, here designated a _{y> mess} or ψ.

In order to ensure the most accurate estimation of the crosswinds size, it is advantageous if a correction of the lateral acceleration quantity a _y , _me βs with respect to disturbances caused due to a roll of the vehicle body around a vehicle oriented longitudinal axis of rotation is made.

In addition to the two sensory acquired driving dynamics variables ay.mess and Ψ, further variables are considered in equations (1.1) and (1.2). These designate with

v _{y is} a time derivative of a transverse speed variable v _y , which describes a vehicle speed in the vehicle transverse direction, g is the gravitational acceleration acting on the vehicle, of the order of g << 9,81 m / s ² ,

Φ a road bank size which describes a road bank at the location of the vehicle,

S _{v is} a lateral force magnitude describing a side force acting on a front axle of the vehicle, EP2005 / 012,738

l _{v is} a distance between the front axle of the vehicle and the center of gravity of the vehicle,

S _{h is} a lateral force magnitude describing a lateral force acting on a rear axle of the vehicle,

Iv is a distance between the rear axle of the vehicle and the center of gravity of the vehicle, e is an aerodynamic quantity that is a distance between the vehicle

Vehicle center of gravity and an aerodynamic point of application of the vehicle,

Jzi is the moment of inertia of the vehicle about a main axis of inertia oriented in the vehicle vertical direction.

For the aerodynamic size e, which ultimately reflects the lever arm of the side wind acting in the center of gravity of the vehicle, a medium constant value is assumed below for the sake of simplicity. The quantities g, l _v , In and J ₂₂ represent physical or vehicle-specific constants, which are stored in addition to the aerodynamic quantity e assumed to be constant, for example in a memory assigned to the estimating device.

According to equation (1.1), the lateral acceleration quantity a _y , meβ ₈ for accurately estimating the side wind magnitude is described both with respect to a lane lateral acceleration component g-Φ describing a lateral acceleration acting on the vehicle due to a lane bank, and with respect to a Coriolis lateral acceleration component Ψ-v _x , which describes a transverse acceleration acting on the vehicle due to Coriolis forces, corrected.

For the lateral acceleration quantity

the equation of determination also applies

m where m denotes the mass of the vehicle. If a possible payload of the vehicle is neglected, the mass m of the vehicle can be assumed to be constant and stored in the form of a corresponding constant in the memory assigned to the estimating device.

If equation (1.3) is used in equation (1.1), the result is immediate

v _y = -Ψ -v _x -g-Φ + ^{Sv + Sh} + ^. (1.4) mm

In Equation (1.2) one finds, inter alia, a relation of the figure

given yaw momentum quantity M _w , in which the aerodynamic quantity e is a function of an approach angle τ "between the direction of the vehicle longitudinal movement described by the Längsgeschwindigkeitsgrδße v _x and the incident on the vehicle center point of incidence direction of the crosswind. The yawing moment variable M "reflects a yawing moment caused by the crosswind, which acts on the vehicle with respect to the center of gravity of the vehicle.

For lateral force forces S _v and S _h linear side force relationships of the shape still apply

and S _h , (1.7)

wherein C _v and C _h denote the skew stiffness of wheels located on the front axle and rear axle of the vehicle, respectively, and δ the steering wheel angle. The variables C _v and Ch are vehicle-specific constants, which are preferably stored in the memory assigned to the estimating device.

In order to simplify the calculation of the crosswinds size mathematically, it is further assumed that the roadway slope Φ and the side wind force magnitude S "change only in an abrupt manner,

Φ = 0, Sw = 0. (1.8)

Furthermore, the side force quantities S _v and S _h can be eliminated by substituting the equations (1.6) and (1.7.) In equation (1.3),

L y, mesB + S, ⁽ 1.9 ⁾

or in a simplified representation

a _y .msββ = C n - V _y + C _l3 - S _w + _β U y (ψ, δ, V _x), (1. 10)

where the sizes S "and v _{y are} still to be determined. In addition, a measurement equation of the shape applies

ψ

-v _y + c ₂₃ -S "+ u _ψ (ψ, δ, v _x ) (1.11)

or in a simplified representation

y = C-x + D-u, (1.12)

and a state equation of the shape Φ = A Φ + B - u (1, 13) S _w

or in a simplified representation

x = A-x + B -u (1. 14)

With

)

For the determination of estimated values S ', v _y and Φ for the sides tenwindkraftgröße S _{w /} lateral velocity variable v _y and the transverse roadway inclination Φ has a corresponding observer concept, for example in the form of a Kalman filter, has proved expedient. The variables S ", _vy and Φ to be determined thus ultimately result from an observation or estimation carried out by means of the Kalman filter.

The observer concept, which is preferably implemented in the estimating device, can furthermore comprise a determination of estimated variables ψ, a _y for the quantities ψ, a., Which are determined by sensor or model. _yimeBB , whereby the deviations ascertained on the basis of a comparison between the sensory and the estimated variables are corrected by means of a correction factor K,

On the basis of the estimated lateral wind force magnitude S ", further crosswind characteristics that are characteristic of the side wind influence exerted on the vehicle can be determined or such as, for example, the angle of incidence τ "of the crosswind or an inflow velocity variable v _re s, which represents a flow velocity occurring in the direction of incidence of the crosswind with respect to the vehicle center. The determination or estimation can take advantage of aerodynamic relationships of the shape

Sw = _-A ₈ -C ₈ (τ _w ) -v ² _re8 , (1.17)

2

respectively. In addition to the estimated side wind force magnitude S ", the two variables t" and v _reB , and a size M "estimated for the yaw moment variable M", other variables are also taken into account in equations (1.17) to (1.19). These designate with

F "an estimated side wind longitudinal force magnitude F _w , which describes a force exerted on the vehicle due to the side wind in the vehicle longitudinal direction, p the air density, of the order of magnitude p" 1, 29 kg / m ³ ,

A ₈ the side wind effective cross-sectional area of the vehicle,

1 the side wind effective length of the vehicle,

C ₈ the aerodynamic coefficient effective in the longitudinal direction of the vehicle, c "the aerodynamic coefficient effective in the transverse direction of the vehicle,

C _n the effective in the vertical direction of the vehicle aerodynamic coefficient. The aerodynamic coefficients c _{S /} c "and c _n are preferably in the form of characteristic curves which may be stored in the memory assigned to the estimating device. The lateral wind longitudinal force variable F _w can be determined or estimated, for example, by evaluating the force and torque balances occurring in the vehicle longitudinal direction.

If, in addition to the equations (1.17) to (1.19), the equation (1.5) valid in an analogous manner for the estimated yaw momentum quantity M _{w is used} ,

Thus, the previously assumed as constant aerodynamic size e can be determined or estimated as a further Seitenwindgrδße. Alternatively, the determination or estimation of the aerodynamic variable e can also take place on the basis of the approach angle τ _w using a predetermined characteristic curve e (τ "), which is stored, for example, in the memory assigned to the estimating device.

In order to avoid that in the case of lateral dynamic critical driving situations, a modification of the RadaufStandskräfte to compensate for the force exerted on the vehicle crosswind influence, there is the possibility that when exceeding a predetermined vehicle inclination angle and / or intervention of an arranged in the vehicle Fahrstabili- and / or when a predetermined steering angle is exceeded at the steerable wheels of the vehicle, the estimation of the crosswinds size is omitted.

The thus estimated side wind size is finally fed to the stabilization device for compensating the side wind influence exerted on the vehicle.

Advantageously, the stabilization device comprises an active chassis, cooperating with the actuating elements Abstützaggregate between the wheels of the vehicle and the vehicle body are arranged, and in which the wheels of one of the vehicle axles have a toe angle, so that can be influenced by individual wheel control of the control elements acting on the individual wheels RadaufStandskräfte such that in the region of the toe angles having wheels a lateral force is generated, which leads to a yaw moment acting on the vehicle.

The stabilization device furthermore comprises a control device which determines a setpoint value suitable for compensating the crosswind influence for a yaw rate variable describing the yaw rate of the vehicle as a function of the estimated crosswinds, wherein the control device adjusts the wheel contact forces by actuation of the control elements such that the yaw rate magnitude is established by establishing a corresponding yaw moment is brought to the determined setpoint. The yaw rate variable preferably describes the yaw rate of the vehicle about an axis of rotation oriented in the vehicle vertical direction and is preferably identical to the yaw rate quantity which is used to estimate the crosswinds.

Such a stabilization device allows a very effective and low-delay influencing the yaw rate of the vehicle and thus the yaw rate described by them, so that a reliable compensation even stronger or sudden side wind influences (gusts, storm, etc.) is ensured.

The relationship between the setpoint value determined for the yaw rate variable and the wheel contact forces is stored, for example, in the control device in the form of a characteristic curve or a corresponding calculation rule. In this case, the control device may be part of a vehicle in the sense of a cost-efficient multiple use Yaw rate control, such as an Electronic Stability Program (ESP).

A particularly robust type of modification of the RadaufStandskräfte can be achieved if the adjusting elements are designed to influence the bias of suspension devices of the vehicle, wherein the modification of RadaufStandskräfte done by modifying the bias of the suspension devices.

In this case, the respective structural design of the suspension devices inherently does not matter. Rather, it can equally be leaf springs and / or coil springs and / or air springs and / or hydraulic springs, so that the stabilization device can be realized in connection with almost any passenger car or commercial vehicle.

Alternatively, the adjusting elements for influencing the bias of arranged in the vehicle stabilizers are formed, wherein the modification of RadaufStandskräfte carried out by modification of the bias of the stabilizers. In particular, the stabilizers may be roll stabilizers of the vehicle which are available as standard and can therefore be used cost-effectively.

The yaw rate magnitude caused by the modification of the wheel contact forces is dependent on the amount of toe-in angle. Since a permanently set large amount of toe-in angle leads to a high degree of tire wear, it is advantageous if the toe-in angle can be influenced by means of adjusting elements, the influence being such that the amount of toe-in angle is only increased if necessary.

Depending on the desired characteristic of the yaw rate control performed by the stabilizer, the be assigned to the toe-in wheels having the front axle and / or the rear axle of the vehicle.

The device according to the invention or the method according to the invention will be explained in more detail below with reference to the accompanying drawings. Showing:

1 shows a schematically illustrated embodiment of the device according to the invention for crosswind stabilization for a vehicle,

2 shows a characteristic curve which illustrates the vehicle-longitudinal effective aerodynamic coefficient c _β (τ "),

3 shows a characteristic curve which illustrates the vehicle-transverse-direction-effective aerodynamic coefficient c _w (τ "),

4 shows a characteristic curve which illustrates the vehicle-height-effective aerodynamic coefficient c _n (τ "),

5 shows a characteristic curve which illustrates a crosswind influence aerodynamic quantity e (τ "),

Fig. 6 is a schematically illustrated embodiment of a trained for influencing RadaufStandskräften stabilization device.

1 shows an exemplary embodiment of the device according to the invention for carrying out the method according to the invention for crosswind stabilization of a vehicle. The device 11 arranged in the vehicle 10 further comprises, in addition to an estimation device 12 for estimating a side wind magnitude, which reproduces a side wind influence exerted on the vehicle 10, a stabilization device 13 provided for influencing the lateral dynamics of the vehicle 10, which is used to modify wheels of the vehicle 10 is formed acting RadaufStandskräften, wherein the stabilizing device 13 modifies the RadaufStandskräfte depending on the crosswinds size such that the force exerted on the vehicle 10 crosswind influence is compensated or at least significantly reduced.

The estimation device 12 estimates the crosswinds based on a vehicle model into which a lateral acceleration quantity a _y , _meS β, which describes a lateral acceleration acting on the vehicle 10 and / or in which a yaw rate Ψ enters, is the yaw rate of the vehicle 10 describes a oriented in vehicle vertical direction of rotation axis.

In the present case, the vehicle model is an easily evaluable linear single-track model for describing the lateral dynamics of the vehicle 10 (cf "Adam Zomotor, Chassis Technology: Driving Behavior", 1st edition, Vogel-Fachbuch, p. ,

The lateral acceleration quantity a _{y> κ} "is provided in the form of a transverse acceleration signal by means of a lateral acceleration sensor 14. The same applies to the yaw rate variable Ψ, which is provided in the form of a yaw rate signal by means of a yaw rate sensor 15. The two sensors 14 and 15 may be part of an existing in the vehicle 10 system for yaw rate control, for example, an electronic stability program (ESP), be.

If the lateral acceleration sensor 14 and / or the yaw rate sensor 15 are not available, determines the Estimating means 12, the lateral acceleration magnitude a _y , m _eB3 and / or the yaw rate Ψ based on suitable models, in which a longitudinal speed V _x , which describes a present in the vehicle longitudinal _{direction vehicle speed} , and / or in the one steering angle δ, the one at steerable wheels of the Vehicle 10 adjustable steering angle describes incoming.

The longitudinal velocity variable V _x results from evaluation of wheel speed signals provided by wheel speed sensors 20 associated with the wheels of the vehicle 10. The same applies to the steering angle variable δ, which is provided in the form of a steering angle signal by means of a steering angle sensor 21, which detects the steering angle set on the steerable wheels of the vehicle 10.

In summary, the estimation device 12 thus estimates based on sensory or model-based determined vehicle dynamics quantities a _y , me8s, Ψ using a suitable vehicle model, in the present case a linear one-track model for describing the lateral dynamics of the vehicle 10 according to equations (1.1) and (1.2). , a cross-wind size that reflects a side wind influence exerted on the vehicle 10.

The lateral wind amount is quantified, inter alia, in the form of a lateral wind force magnitude S _w , which describes a crosswind force exerted on the vehicle 10 due to the crosswind.

In order to ensure the most accurate estimation of the side wind force magnitude S ", the estimation device 12 additionally takes a correction of the lateral acceleration variable a. _yιmeBg with regard to interference caused by a sway of the vehicle body about an axis oriented in the vehicle longitudinal axis of rotation before. As already mentioned, the estimation of the lateral wind force quantity S "is based on the equations (1.1) and (1.2), the estimator 12 additionally taking into account further correlations or explanations according to the equations (1.3) to (1.15). The arithmetic operations to be carried out in accordance with equations (1.1) to (1.15) for estimating the crosswind force S _w are stored here in the estimator 12 in the form of a data processing program.

In addition to the two sensory or model-based determined driving dynamics quantities a _y ,, ne-8 / Ψ, other parameters are also taken into account in the relationships and explanations given by equations (1.1) to (1.15). These designate - as already explained in connection with the relevant equations (1.1) to (1.15) - with

v _{y is} a time derivative of a transverse speed variable v _y , which describes a vehicle speed present in the vehicle transverse direction, g is the gravitational acceleration acting on the vehicle 10, of the order of magnitude g << 9.81 m / s ² ,

Φ a road bank size describing a road bank at the location of the vehicle 10,

Sv is a lateral force magnitude describing a side force acting on a front axle of the vehicle 10, l _{v is} a distance between the front axle of the vehicle 10 and the vehicle center of gravity SP,

Sh is a lateral force magnitude which describes a lateral force acting on a rear axle of the vehicle 10, l _{v is} a distance between the rear axle of the vehicle 10 and the vehicle center of gravity SP, P2005 / 012738

18

e is an aerodynamic quantity representing a distance between the vehicle center of gravity SP and an aerodynamic attack AP of the vehicle 10,

M "a yaw momentum M" representing a yawing moment caused by the side wind, which acts on the vehicle 10 with respect to the vehicle center of gravity SP, τ "is an angle of approach between the direction of the vehicle longitudinal motion described by the longitudinal velocity variable v _x and the vehicle center point MP Direction of the crosswind,

J _"is the moment of inertia of the vehicle 10 about a main axis of inertia oriented in the vehicle vertical direction, m is the mass of the vehicle 10,

C _{v is} the skew stiffness of wheels located on the front axle of the vehicle 10,

C _h the skew stiffness of located on the rear axle of the vehicle 10 wheels.

Some of the aforementioned sizes are shown in FIG.

For the aerodynamic size e, which ultimately reflects the lever arm of the side wind acting in the vehicle center of gravity SP, a medium constant value is assumed below for the sake of simplicity. The quantities g, l _v , U, J ", m, Cv and Ch represent physical or vehicle-specific constants, which are stored in addition to the aerodynamic quantity e assumed to be constant in a memory 12a assigned to the estimating device 12.

The side forces S _v and Sh are computationally eliminated and thus play no part in the estimation of the crosswind force S ".

For determining estimated variables S _w , v _y and Φ for the lateral wind force magnitude S ", the lateral velocity variable v _y and the lane bank size Φ is implemented in the estimator 12 as an observer concept in the form of a Kalman filter, where the determination of the estimated quantities S ", v _y and Φ is done by integrating a relationship according to equations (1.12) and (1.14). The variables S _{w /} Vy and Φ to be determined thus ultimately result from an observation or estimation carried out by means of the Kalman filter.

The observer concept further provides for a determination of estimated variables ψ, _{y y} for the quantities ψ, a _y determined by the sensory method or model-based. _m eβs before, wherein the determination of the estimated quantities ψ, _{y y takes place} by integration of a relationship according to equation (1.12). Detected the detected based on a subsequent comparison of differences between the model-based sensory or determined variables ψ, a _y, _me8 s and the calculated estimated quantities ψ, ä _y are corrected by a correction factor K in accordance with equation (1.16).

On the basis of the estimated lateral wind force magnitude S ", the estimating device 12 determines further side wind variables characteristic of the side wind influence exerted on the vehicle 10, for example the angle of incidence τ _w and / or an inflow velocity v _reβ , which relates a flow velocity occurring in the direction of incidence of the crosswind with respect to the vehicle center MP reproduces. The determination or estimation takes place using aerodynamic relationships according to the equations (1.17) to (1.19), wherein besides the estimated side wind force size S _w , the two variables τ _w and v _reB , and one for the yaw moment size M "estimated size M" more Sizes are taken into account. These designate - as already explained in connection with the equations (1.17) to (1.19) - with Fw is an estimated value for a lateral wind longitudinal force magnitude F ", which describes a force exerted on the vehicle 10 due to the side wind in the vehicle longitudinal direction, the air density, of the order p» 1.29 kg / irr

A _8, the side wind effective cross-sectional area of the vehicle 10,

1 the lateral wind effective length of the vehicle 10, c _s the effective in the vehicle longitudinal direction aerodynamic coefficient, c, the effective in the vehicle transverse direction aerodynamic coefficient,

C _n the effective in the vehicle vertical direction aerodynamic coefficient.

Some of the aforementioned sizes are shown in FIG. The estimated variable F _w is determined or estimated by evaluating the forces and torque balances occurring in the vehicle longitudinal direction.

The aerodynamic coefficients c _{β #} c "and c _n are in the form of characteristic curves whose course is illustrated by way of example by FIGS. 2, 3 and 4.

It should be noted at this point that the aerodynamic coefficient c "can also be given a constant value for simplicity, for example of the order of magnitude c _w " 0.38.

In addition or as an alternative to the flow angle τ "and / or the flow velocity variable v _res , another side wind size is the aerodynamic variable e previously assumed to be constant. The determination or estimation of the aerodynamic quantity e takes place either by using a relationship according to equation (1.20) or - as assumed in the present case - on the basis of the angle of incidence τ _w using a predetermined characteristic curve. never e (τ "), the course of which is exemplified by FIG. 5.

The characteristic curves of FIGS. 2 to 5 are preferably stored in the memory 12a associated with the estimating device 12.

In order to avoid that in the case of critical lateral driving situations a modification of the wheel contact forces to compensate for crosswind influence is performed, the estimation of the cross wind force S "and thus the determination or estimation of the other crosswinds tw, v _{re8 /} e is exceeded when a predetermined vehicle _{inclination angle} and / or upon intervention of a vehicle stability control system 10 and / or exceeding a predetermined steering angle at the steerable wheels of the vehicle 10th

The thus-estimated wind page size S "and the side wind variables determined or estimated on the basis of τ" _r v e _{S /} e of the stabilization device 13 can be supplied to compensate for the force exerted on the vehicle 10 side wind influence subsequently.

Fig. 6 shows an embodiment of the stabilization device.

The stabilization device 13 arranged in the vehicle 10 comprises, for example, an active chassis in which support units 26 interacting with hydraulically controllable positioning elements 25 are arranged between the wheels 27a to 27d of the vehicle 10 and the vehicle body 28. The support units 26 have spring devices 29 connected in series with the adjusting elements 25, with damping devices, not shown, in addition to the series connection of the adjusting elements 25 and the spring devices 29 for vibration damping of the vehicle body 28 are connected in parallel.

The adjusting elements 25 are in this case designed to influence the bias of the suspension devices 29, wherein the modification of the forces acting on the wheels 27a to 27d of the vehicle 10 RadaufStandskräfte Fn to F _{14 takes place} accordingly by modifying the bias of the suspension devices 29. The spring devices 29 are, for example, air springs, wherein additionally or alternatively, coil springs and / or leaf springs and / or hydraulic springs can be provided.

Alternatively, the adjusting elements 25 are designed to influence the bias of a vehicle 10 arranged stabilizer device for roll stabilization, wherein the modification of the wheel contact forces Fn to F _{14 takes place} in this case by modification of the bias of the stabilizer device.

For the hydraulic control of the actuating elements 25, an electromechanical valve unit 30 is provided, which is part of the stabilizing device 13 and which is fed by a pressure source located in the vehicle 10. The instantaneous position or the instantaneous travel of the adjusting elements 25 relative to the vehicle body 28 is detected by means of travel sensors 35, which are also part of the stabilizing device 13 and their travel signals conclusions on the instantaneous bias of the suspension devices 29 and thus on the wheels 27a to 27d radindividuell allow acting wheel contact forces Fn to Fi ₄ . The travel signals provided by the travel sensors 35 are in this case supplied to the stabilization device 13 for precise adjustment of the respectively desired wheel contact forces F _u to Fi ₄ . The active suspension system is further configured such that the wheels 27a to 27b of both the front axle and the rear axle of the vehicle 10 each have a predetermined toe angle α, so that in conjunction with a travel movement of the vehicle 10 Radseitenkräfte F _u to F ₁ ⁸ , occur, the amounts of which currently acting wheel contact forces Fn to F ₁₄ depend directly.

If the wheel contact forces Fn to Fi ₄ acting on the wheels 27a to 27d of the vehicle 10 are the same, and if the wheels 27a to 27d of the vehicle 10 each have identical amounts for the toe-in angle α, then the wheel side forces F ₁ to F occur ₁ ⁸ , in turn, the same size. As a result, no resultant transverse force is caused in the area of the wheels 27a to 27d having the toe-in angle α.

Now assume that the adjusting elements 25 are individually for each wheel controlled such that the increase to the wheels 27a, 27d acting wheel contact forces F _11, F _14, respectively to a power amount .DELTA.F and the forces acting on the wheels 27b, 27c wheel contact forces F _12, F ₁₃ are each reduced by a force amount .DELTA.F. The caused on the wheels 27a, 27d due to the toe angle α on the wheels 27a, 27d Radseitenkraft F _n , F ₁ ⁸ , then in terms of magnitude greater than the wheels 27b, 27c caused Radseitenkraft F ₁ "., F ₁ *, since by the amount of force .DELTA.F higher loaded wheels 27a, 27d, a lower lateral wheel slip comprise as the low to the amount of force .DELTA.F loaded wheels 27b, 27c. This occurs in the area of the wheels 27a to 27d, a resultant lateral force ~ ^F i ₂ bzw- ^F i ^S _4-F ₁₃ ^au f / in the present case has an acting on the vehicle 10 left-handed yaw moment M result.

This yaw moment M is now used to compensate for the force exerted on the vehicle 10 crosswind influence. The stabilization device 13 comprises a control device for this purpose. tion 36, the one dependent on the estimated Seitenwindkraft- large S, and the determined or estimated side wind sizes τ _w , v _res , e one according to the condition

M.ou = -M ". (2.1)

to compensate for the crosswind influence suitable setpoint Ψsoii for the yaw rate Ψ determined. In this case, the control device 36 adjusts the wheel contact forces Fn to Fi ₄ by appropriate actuation of the adjusting elements 25 in such a way that the yaw rate Ψ is brought to the determined desired value Ψ _β by building up a corresponding yawing moment M and the crosswind influence is compensated.

The adjustment of the wheel contact forces Fn to Fj ₄ takes place as a function of the desired value Ψ _B oii itself and / or the control deviation Ψsoii -Ψ present between the desired value Ψ _so ii and the yaw rate Ψ using a characteristic curve or calculation rule stored in the control device 36.

The yaw moment M caused by the modification of the wheel contact forces Fn to Fi ₄ is ultimately dependent on the predetermined amount of the toe-in angle α. Since a permanently set large amount of the toe-in angle α leads to a high degree of tire wear, the toe-in angle α is influenced by means of adjusting elements, not shown, in such a way that its amount is increased only when necessary. The adjusting elements are arranged for example in tie rods of the front axle and the rear axle.

Depending on the desired characteristic of the yaw rate control carried out by the stabilization device 13, the wheels having the toe-in angle α can also be assigned exclusively to the front axle or the rear axle of the vehicle 10. At the principle of operation of the stabilizer 13 this changes nothing.

Claims

claims

1. A device for crosswind stabilization of a vehicle, comprising an estimation device (12) for estimating a side wind magnitude that reflects a side wind influence exerted on the vehicle (10), and a stabilization device (13) for influencing the lateral dynamics of the vehicle (10) ) to which the estimated lateral wind amount is supplied for compensating the side wind influence exerted on the vehicle (10), characterized in that the stabilizing device (13) modifies wheel contact forces acting on wheels (27a, ..., 27d) of the vehicle (10) (Fn,..., Fi "), wherein the stabilizing device (13) modifies the wheel contact forces (Fn,..., Fi ₄ ) as a function of the side wind magnitude in such a way that the side wind exerted on the vehicle (10) is influenced is compensated.

2. Device according to claim 1, characterized in that the estimation device (12) estimates the crosswinds size on the basis of a vehicle model into which a lateral acceleration variable (a _y , _me β.), The one on the vehicle

(10) describes acting lateral acceleration, and / or a yaw rate quantity (ψ) representing a yaw rate of the vehicle

(10) describes, received.

3. Device according to claim 2, characterized in that the vehicle model is a linear single-track model for describing the lateral dynamics of the vehicle (10).

4. The device according to claim 2, characterized in that the lateral acceleration _variable (a _y , _meB s) in the form of a lateral acceleration signal by means of a transverse acceleration sensor (14) and / or that the yaw rate (ψ) in the form of a yaw rate signal by means of a yaw rate sensor (15 ) provided.

5. The device according to claim 2, characterized in that the estimation means (12) performs a correction of the lateral acceleration amount (ay.meεs) with respect to disturbances caused due to a roll of the vehicle body (28).

6. Apparatus according to claim 2, characterized in that the estimating means (12) describes a correction of the lateral acceleration quantity (a _{y / mess} ) with respect to a lane lateral acceleration component which describes a lateral acceleration acting on the vehicle (10) due to a lane bank, and or with respect to a Coriolisquerbeschleunigungskomponente which describes a due to Coriolis forces on the vehicle (10) acting lateral acceleration performs.

7. The device according to claim 1, characterized in that the estimating device (12) for estimating the crosswinds size, a steering angle variable (δ), the one steerable wheels of the vehicle (10) adjustable steering angle describes, and / or a longitudinal speed variable (v _x ), which describes a present in the vehicle longitudinal direction vehicle speed, evaluates.

8. The device according to claim 1, characterized in that in the estimation device (12) an observer concept for reducing deviations between sensor-detected and mathematically estimated quantities is implemented.

9. The device according to claim 1, characterized in that the side wind size a Seitenwindkraftgröße (S,) which describes a due to crosswind influences on the vehicle (10) applied cross wind force, and / or an angle of attack (τ ") between the direction of the vehicle longitudinal movement and the incident direction of the side wind, which is related to the center of the vehicle, and / or an inflow velocity variable (v _re e) / which reflects a inflow velocity with respect to the center of the vehicle occurring in the direction of incidence of the side wind, and / or an aerodynamic variable (e) which is a distance between the vehicle center of gravity and an aerodynamic point of application of the vehicle (10).

10. The device according to claim 1, characterized in that the estimation of the side wind size when exceeding a predetermined vehicle inclination angle and / or upon intervention of a in the vehicle (10) arranged Fahrstabi- litätssystems and / or when exceeding a predetermined steering angle at steerable wheels of the vehicle (10 ) is omitted.

11. The device according to claim 1, characterized in that the stabilization device (13) comprises an active suspension system, in which with control elements (25) cooperating support units (26) between the wheels (27a, ..., 27d) of the vehicle (10). and the vehicle body (28) are arranged, and in which the wheels (27a, ..., 27d) of one of the vehicle axles have a toe-in angle (α), so that by wheel-individual control of the control elements (25) at the individual wheels (27a ..., can be modified in such a way, 27d) acting wheel contact forces (Fu, ..., F _i4) that is ..., 27d caused in the area of the toe-in angle (α) having wheels (27a), a resultant lateral force which leads to a yawing moment (M) acting on the vehicle (10), the stabilizing device (13) further comprising a control device (36) which, in dependence on the estimated crosswindsize, compensates for the lateral force exerted on the vehicle (10) indeinflusses suitable setpoint (Ψ _8O π) of a yaw rate of the vehicle (10) descriptive yaw rate (Ψ) determined, the control device (36) the RadaufStandskräfte (F ₁₁ , ..., Fi ₄ ) by controlling the control elements (25) such sets the yaw rate (Ψ) by building up a corresponding yawing moment (M) to the determined setpoint (Ψsoii) is introduced.

12. The device according to claim 11, characterized in that the adjusting elements (25) for influencing the bias of a suspension device (29) of the vehicle (10) are formed, wherein the modification of the Radauf- standing forces (F ₁₁ , ..., Fi ₄ ) by modification of the bias of the suspension device (29).

13. The apparatus according to claim 12, characterized in that the suspension device (29) is a leaf spring and / or a coil spring and / or an air spring and / or a hydraulic spring.

14. The apparatus according to claim 11, characterized in that the adjusting elements (25) for influencing the bias of a vehicle (10) arranged stabilizer means are formed, wherein the modification of RadaufStandskräfte (Fu, ..., F ₁₄ ) by modifying the bias the stabilizer device takes place.

15. The apparatus according to claim 11, characterized in that the toe-in angle (α) can be influenced by means of adjusting elements.

16. The apparatus according to claim 11, characterized in that the toe-in angle (α) having wheels

(27a, ..., 27d) are associated with a front axle and / or a rear axle of the vehicle (10).

17. A method for crosswind stabilization of a vehicle, in which a side wind size is estimated, which reflects a side wind influence exerted on the vehicle (10), wherein to compensate for the force exerted on the vehicle (10) crosswind influence the transverse dynamics of the vehicle (10) in dependence of the estimated Side wind size is affected, characterized in that for influencing the transverse dynamics of the vehicle (10) on wheels (27a, ..., 27d) of the vehicle (10) acting Radauf- standing forces (F _X1 , ..., F ₁₄ ) are modified , wherein the RadaufStandskräfte (F ₁₁ , ..., F ₁₄ ) are modified depending on the crosswind size such that the on the Vehicle (10) applied crosswind influence is compensated.