EP2934924A1

EP2934924A1 - Method for combined determining of a momentary roll angle of a motor vehicle and a momentary roadway cross slope of a curved roadway section traveled by the motor vehicle

Info

Publication number: EP2934924A1
Application number: EP13785362.8A
Authority: EP
Inventors: Dieter Ammon; Claus-Michael Hainbuch; Magnus Rau
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2012-12-20
Filing date: 2013-10-31
Publication date: 2015-10-28
Also published as: WO2014094933A1; DE102012024971A1; CN104853941A; US20160001783A1; US9849886B2

Abstract

The invention relates to a method for combined determining of a momentary vehicle roll angle (φ _Α) of a motor vehicle and a momentary roadway cross slope (φ _FΒ) of a curved roadway section (20) traveled by the motor vehicle, according to which the momentary roadway cross slope (φ _FΒ) and the momentary vehicle roll angle are determined from chassis data and transverse dynamics data of the motor vehicle (1).

Description

A method for combined determination of a current roll angle of a motor vehicle and a current road-bank of a curvy road section traveled by the motor vehicle

The invention relates to a method for combined determination of a current roll angle of a motor vehicle and a current road-bank of a curvy road section traveled by the motor vehicle and a device for combined determination of this instantaneous roll angle and this current road-bank. The invention further relates to a motor vehicle with such a device.

The term "Active Body Control (ABC)" are electro-hydraulically active

Suspension systems are known, which also allow the possibility of selective adjustment of pitch and roll angles in addition to a conventional suspension and damping function. As a roll is called thereby a rotary motion of a motor vehicle about its longitudinal axis. Such a rolling motion can result when driving through a curved roadway section through the motor vehicle when the motor vehicle tilts outward due to the centrifugal forces occurring at a certain roll angle. The thereby adjusting roll angle depends on a lateral acceleration of the motor vehicle whose center of gravity, the

Suspension structure of the motor vehicle and its speed from.

The occurring when driving on the curved roadway section

Centrifugal forces are often perceived by occupants of the motor vehicle as unpleasant and can therefore lead to a significant reduction in ride comfort. One way to reduce the comfort-reducing effect of such undesirable lateral forces on the occupants of the motor vehicle, is to realize in the motor vehicle by means of "Active Body Control (ABC)" a tilting technology, as they have been used for some time in rail vehicles By using such a tilting technique, it is possible that the force or Railway vehicle when driving on a curved lane or

Rail section not centrifugally due to the outside, but by appropriate control of a chassis of the motor vehicle in the opposite direction, ie inward tends. For this purpose, the chassis with suitable actuators, for example in the manner of height-adjustable struts, be provided, which connect the vehicle frame height adjustable each with the wheels of the motor vehicle, so that a certain roll angle of the motor vehicle can be adjusted.

Since the centrifugal forces occurring when driving on the curved roadway section of various factors such. Depending on a roadway curvature of the road section or the current speed depend also to be set in terms of a tilting technology on the chassis of the motor vehicle roll angle depending on these parameters to ensure the highest possible driving comfort in the occupants of the motor vehicle. In order to achieve maximum ride comfort, it may be necessary to take into account when setting a certain roll angle in the motor vehicle, a current road-bank of the curvilinear roadway section currently being traveled by the motor vehicle. For often the road used by the motor vehicle is not oriented horizontally in its transverse direction with respect to a reference vector of gravity which defines a horizontal plane of the earth's surface, but is inclined relative to this "horizontal reference plane". In particular, a curved roadway section may be inclined outwardly with respect to its curve curvature, for example, for dewatering rainwater striking the road surface or the like. to facilitate. Conversely, the roadway may also be inclined inwards in the direction of the curve, also in the manner of a so-called curve elevation, in order to make it easier for the motor vehicle to drive on the curved roadway section. This means, however, that in each case the roadway bank of the roadway relative to the horizontal reference plane in the control of a chassis of the

Motor vehicle must be considered to set an optimal roll angle of the motor vehicle.

DE 10 2010 046 317 A1 describes a method for adjusting the spatial position of a roll axis about which the motor vehicle is rotatable about a predetermined roll angle. According to the method, a spatial desired position of the position of the roll axis is first determined in a first step and then in a second Step determines a lateral acceleration of the motor vehicle. In a third step, finally, a desired bank of the motor vehicle and a desired transverse storage of the motor vehicle is determined as a function of the lateral acceleration, so that when setting the desired bank and the desired transverse storage a shift of

Roll axis is effected in the desired position. In order to ensure that the motor vehicle assumes the desired bank determined in the preceding step, at least one actuator of an active chassis device of the motor vehicle is adjusted accordingly. In addition, at least one actuator for influencing the transverse movement of the motor vehicle is adjusted in such a way that the motor vehicle additionally assumes the desired transverse deposit determined in the preceding step. The expected

Transverse acceleration can be determined for example with the aid of a camera system mounted on the motor vehicle, which is the curved to be traveled

Lane section in the apron of the motor vehicle optically detected and analyzed to determine the expected lateral acceleration.

DE 10 2006 018 978 A1 describes a method for determining the roll angle of a motor vehicle with at least one device for determining the yaw rate or a variable correlated therewith and a device for determining the yaw rate

Vehicle speed and an optionally forward facing

Camera system. The roll angle is determined using the yaw rate or a magnitude correlated therewith and the specific roll stiffness of the vehicle.

It is an object of the present invention to provide an improved embodiment of a method for combined determination of a current one

Wankwinkels a motor vehicle and a current road-bank of a motor vehicle driven on the curved road section indicate. It is also an object of the present invention to provide an apparatus for determining such a current road bank.

The above object is solved by the subject matter of the independent

Claims. Preferred embodiments are the subject of the dependent

Claims.

The invention is based on the general idea when driving on a

curved lane section both the entire current vehicle Roll angle of the motor vehicle relative to a horizontal reference plane and a current road-bank of the traveled by the motor vehicle curved track section relative to the horizontal reference plane

Chassis data and lateral dynamics data of the road section traveled motor vehicle to determine. As already explained, a horizontal reference plane means a plane perpendicular to a direction vector of the gravitational acceleration; Relative to this reference plane, the roadway section traveled by the motor vehicle can be inclined in the transverse direction.

The inventive method can be carried out in a simple manner in a motor vehicle, as determined by the built-in motor vehicle chassis data and lateral dynamics data for a variety of purposes by default and transmitted, for example, to a built-in motor vehicle control unit, the control unit based on these data different

Vehicle components, in particular the chassis, the motor vehicle controls.

The method according to the invention can be carried out in real time in a motor vehicle, in particular in a control unit (ECU) or the like installed in the motor vehicle, so that these data are based on the instantaneous road bank angle determined by the method according to the invention or the instantaneous vehicle roll angle optionally be taken into account in the control of the chassis of the motor vehicle or other vehicle components.

In a preferred embodiment, the chassis data includes a current tire roll angle of the tires of the motor vehicle and / or a current one

Chassis roll angle of the chassis of the motor vehicle. The instantaneous suspension roll angle can be determined by means of a suitable sensor installed on the spring struts of the chassis. Alternatively, however, it can also be thought that the determination of the chassis roll angle takes place without such a sensor, for example, if by means of the control unit, the struts of the chassis for

Setting a specific vehicle roll angle are controlled directly. In this case, the set chassis roll angle can also be read directly from the control unit, which controls the struts of the chassis. The same applies to the tire roll angle of the tires of the motor vehicle, which in particular a wheel load change between the left and right tires of the motor vehicle and Depending on a tire pressure-dependent stiffness of the tire and therefore can be determined by means of suitable, built on the tires of the motor vehicle (tire pressure) sensors. According to this embodiment, the lateral dynamics data comprise a momentary lateral acceleration of the motor vehicle. The momentary

Transverse acceleration of the motor vehicle can be determined by means of an acceleration sensor installed in the motor vehicle.

In a particularly preferred embodiment, the method according to the invention may comprise two successive process steps S1 and S2. In the first method step S1, the instantaneous vehicle roll angle φ _Α is calculated from the instantaneous lateral acceleration a _y , the instantaneous speed v _x and the instantaneous yaw rate d / dt ψ of the motor vehicle according to the relationship φ _Α = (1 / g) (a _y - v _x d / dt ψ). In a second step S2 the current roadway is then bank (9FB) from the calculated in step S1 current vehicle roll angle (<p _A), an instantaneous suspension roll angle (w) and a current tire-roll angle (q> _R) calculated according to the relationship φ _ΡΒ = φ _Α - - <p _R.

In a particularly preferred embodiment, it may be thought that the determination of the current road-bank using GPS-based map material of the traveled curved lane section in

Interaction with a GPS receiver for determining the current vehicle position of the motor vehicle takes place. Since even in modern map material information on local road banks are not present or only with low accuracy, such use can be made primarily only in a complementary manner in the inventive determination of the current road bank.

The invention also relates to an apparatus for combined determination of a current vehicle roll angle of a motor vehicle and a current road bank of a curvilinear road section traveled by the motor vehicle. The device according to the invention comprises a control unit which can be brought into communication with a transverse acceleration sensor, a yaw rate sensor and a speed sensor of the motor vehicle for the transmission of a respective measured instantaneous lateral acceleration or instantaneous speed to the control unit. The control unit according to the invention determines from chassis data and lateral dynamics data, which the instantaneous lateral acceleration or instantaneous speed of the motor vehicle, using the method according to the invention, the instantaneous vehicle roll angle of the motor vehicle and the current road-bank of the curvy road section traveled by the motor vehicle.

The invention also relates to a motor vehicle with a previously explained

Device and with a lateral acceleration sensor, a yaw rate sensor and a speed sensor, each with the control unit for transmitting a measured instantaneous lateral acceleration, a current

Yaw rate or a current speed of the motor vehicle are in communication.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

In each case show schematically:

Fig. 1 is a rough schematic flow diagram of the invention

process

Fig. 2 shows a motor vehicle with a device according to the invention for adjusting the

Curve slope of a motor vehicle, wherein the figure 2a shows a plan view and Figure 2b shows a rear view of the motor vehicle. 1 shows a flowchart of the method according to the invention in a roughly schematic manner, according to which, in a first step S1, an instantaneous roll angle φ _{Α of} the motor vehicle 1 relative to a horizontal reference plane 21 (see FIG. 2b) and in a subsequent step S2 the instantaneous road-surface bank angle φ _Ρ of the curved roadway section 20 currently being traveled by the motor vehicle 1 is determined relative to the reference plane 21.

The horizontal reference plane 21 is over the direction vector g of

Gravity, which extends in the orthogonal direction to the reference plane 21.

To calculate the roll angle φ _Α , a knowledge of the instantaneous speed v _{x of} the motor vehicle 1 is required, which can be determined by means of a speed sensor 6 installed in the motor vehicle 1. Furthermore, a calculation of the roll angle φ _{Α is} also a knowledge of the momentary

Transverse acceleration a _y ^sensor required, which in turn means of one in the

Motor vehicle 1 built lateral acceleration sensor 3 can be determined.

In the transverse acceleration a _y ^{Se sor} measured by the lateral acceleration sensor 3 are according to the equation

_ bensor _ _{Λ Λ} _ _. "_ ■

a _y = a _y cos φ _Α + g sin φ _Α gravity-related so-called "g-shares" included. In the above equation, g is the

Acceleration of gravity and a _y the lateral acceleration without g-share. For small roll angles φ _Α , this equation is simplified by means of Taylor development as follows: a _ _y sensor _ - a _ _y +. g _ φ _Α

From the known and the driving dynamics of a motor vehicle

descriptive relationship _a ^ ensor _{= d / dt Vy} + _{vd (ft ψ} follows for small speed changes (d / dt v _y »0) by combining with the above equation:

<p _A = (1 / g) (a _y ^sensor - v _x d / dt ψ)

From this equation, therefore, the roll angle φ _Α can be calculated. In this case, d / dt ψ is the yaw rate of the motor vehicle 1, which can be determined by means of a yaw rate sensor 5.

Through the use of different indices y and x is to be expressed that a direction vector of the current lateral acceleration a _y ^sensor (in the Y direction) in one to the corresponding direction vector of the current

Speed v _{x of} the motor vehicle (in the X direction) orthogonal direction points (see also Figure 2a). The Z direction is orthogonal to both the X and Y directions.

The sensor output data of the acceleration sensor 3, ie the instantaneous

Transverse acceleration a _y ^sensor , can be filtered by means of a suitable low-pass filter to filter out unwanted high-frequency interference (for example, due to bumps in the roadway section 20 just traveled).

Advantageously, the acceleration sensor 3 in the motor vehicle with respect to a vehicle longitudinal direction L of the motor vehicle as far as possible on the front of the vehicle is arranged (see Fig. 2a).

In step S2, based on the roll angle φ _θ calculated in step S1, the relationship is now determined

<PFB = <PA - w - φ _ρ calculate the required road bank angle <p _FB . In this case, w is a momentary chassis roll angle set in the chassis of the motor vehicle and <p _{R is} a tire roll angle of the tires 13, 14 of the motor vehicle. In a simplified variant of the tire roll angle φ _{κ can} also be neglected (q> _R = 0). To carry out step S2, the instantaneous chassis roll angle w can be determined by means of suitable sensors 2. These sensors can determine an instantaneous height Xi, x _r of the height-adjustable spring struts 11, 12 assigned to the left or right tires 13, 14 of the motor vehicle 1, so that from a height difference Δχ = 1 Xi -x _r l the instantaneous height x, the left struts 11 relative to a current height x _{r of} the right struts 12 of the current suspension roll angle w can be determined.

In an analogous manner, the tire roll angle φ _κ can also be determined by means of suitable sensors 4. For this purpose, by means of such sensors 4 a height difference Ay = | y, - y _r | a current height y, y _{r of} the left tires 13 relative to the right tires 14 are determined. This height difference Ay may depend on a different wheel load of the left and right tires 13, 14 of the motor vehicle 1 and a different, tire pressure-dependent stiffness of the left and right tires 13, 14. The sensors 4 can therefore tire pressure sensors for measuring the individual

Tire pressure in the tires 13, 14 include.

In the illustration of Figure 2, the motor vehicle 1 is now shown with a device 7 according to the invention for carrying out the method according to the invention. FIG. 2a shows motor vehicle 1 in a plan view, FIG. 2b in a rear view. The motor vehicle 1 comprises a control unit 8 and an acceleration sensor 3, a yaw rate sensor 5, and a speed sensor 6, which in each case with the

Control unit 8 are in communication.

The motor vehicle 10 comprises a chassis device which can be controlled by the control device 8 and which can be designed in the manner of an electro-hydraulically active chassis. The chassis device comprises four actuators 11, 12 designed as height-adjustable struts, wherein each actuator 13, 14 of the motor vehicle 10 is assigned an actuator 11, 12. By an individual adjustment of the parking height of the actuators 11, 12, a certain roll angle φ _Α can be adjusted to the motor vehicle 10.

As an alternative to the electro-hydraulic suspension device described above, it is also possible to use an air-spring-based chassis with a closed pressure supply. In such a spring-based suspension to adjust the struts, the air is pumped in a closed circuit of an air reservoir in the air spring and vice versa, which is a very fast retraction and extension of Suspension struts for setting the desired curve inclination in the chassis of the motor vehicle allows.

In a further alternative to the electro-hydraulically active chassis, a hydraulically adjustable undercarriage known as "ACTIVE CURVE SYSTEM" can be used, which operates with a belt-driven hydraulic pump and an oil tank in the engine compartment as well as a valve block and active stabilizers Has front and rear axle. Such a hydraulic suspension device can also be used to set the desired curve inclination in the motor vehicle.

For carrying out the method according to the invention, the

Acceleration sensor 3, the current sensor lateral acceleration a _y , the

Speed sensor 6, the current speed v _x and the yaw rate sensor 5 of the motor vehicle 1, the current yaw rate d / dt ψ to the control unit 8. The control unit 8, a control unit 9 (ECU) and one with the

Control unit 9 in communication connection storage unit 10 include. The control unit 9 and the memory unit 10 may be formed in the manner of a conventional microcontroller, wherein the person skilled in numerous technical implementation possibilities are known.

In the control unit 8, the inventive method is performed using the above-mentioned input parameters (instantaneous speed of the motor vehicle v _x , yaw rate d / dt ψ, current sensor lateral acceleration a _y ^sensor ). For this purpose, the control unit 8 according to step S1 of

According to the invention, the instantaneous vehicle roll angle φ _Α of

Motor vehicle 1 calculated. From the instantaneous vehicle roll angle φ _Α , according to step S2, the current road-bank angle (p _F E) of the curved roadway section 20 currently being traveled is calculated.

In order to determine the instantaneous chassis roll angle w in the context of the execution of step S2, the device 7 according to the invention can have suitable chassis sensors 2, which have the respective instantaneous height X | , x _{r of} the height-adjustable

Determine struts 11, 12, so that the control unit 8 from the height difference Δχ = | Xi - x _r | the current altitude X | of the two left tires 13 associated struts 11 relative to the current height x _r of the two right tires fourteenth associated struts 12 can determine the current chassis roll angle w. In an analogous manner, the tire roll angle <p _R can also be determined by means of the (tire pressure) sensors 4.

In a further development variant, it may also be envisaged not to determine the instantaneous chassis roll angle w as explained above by means of a suitable sensor system 2; Rather, according to this alternative, it can also be thought of by means of a suitable method, for example as a function of certain input parameters such as the instantaneous lateral acceleration a _y ^sensor and the instantaneous speed v _{x of} the motor vehicle 1 and a momentary road curvature K of the roadway currently being driven. Section 20 of these

Input parameters an optimal target roll angle w _So u to be calculated in the spring struts 11, 12 of the chassis of the motor vehicle 1 to be set when driving on the curved lane section 20 on the occupants of the

To reduce motor vehicle 1 acting lateral forces and thus to increase the ride comfort for the occupants. The calculation of the desired roll angle w _So n initially takes place independently of the current roadway cem slope cp _FB . The calculation of the desired roll angle w _S0 ii can be carried out, for example, by the control unit 9 of the control unit 8. The height-adjustable struts 11, 12 can be controlled by the control unit 8, so that the desired desired roll angle w _So n in the chassis of the motor vehicle 1 sets. Since in such a simplified calculation of the desired roll angle w _S oii the current road-bank angle cp _{FB is} disregarded, it makes sense, this means of the invention

Calculate method and in the adjustment of the chassis roll angle w _So n by the spring legs 11, 12 of the chassis to be considered.

Claims

claims

Method for combined determination of a current vehicle roll angle (φ _Α ) of a motor vehicle (1) and a current road bank (cp _FB ) of a curved road section (20) traveled by the motor vehicle (1),

according to which the current road-bank angle (<p _FB ) and the current vehicle-roll angle (φ _Α ) are determined from chassis data and lateral dynamics data of the motor vehicle (1).

Method according to claim 1,

characterized in that

the chassis data comprise a current chassis roll angle (w) of a chassis of the motor vehicle (1),

the chassis data comprise a current tire roll angle (cp _R ) of the tires (13, 14) of the motor vehicle (1),

the lateral dynamics data comprise an instantaneous lateral acceleration (a _y ^sensor ) of the motor vehicle (1),

Method according to claim 2,

characterized in that

the method comprises the following steps:

S1) calculating the current vehicle roll angle (<p _A ) from the instantaneous lateral acceleration (a _y ^sensor ), the current speed (v _x ) and the current yaw rate (d / dt ψ) of the motor vehicle (1) according to the following relationship:

<p _A = (1 / g) (a _y ^sensor - v _x d / dt ψ) S2) calculating the current road-bank angle (cp _FB ) from the instantaneous vehicle roll angle (φ _Α ) calculated in step S1, a current vehicle roll angle (w), and a current tire roll angle (cp _R ) according to the relationship: φ _ΡΒ = φ _Α - w - <p _R.

Device (7) for combined determination of a current vehicle roll angle (φ _Α ) of a motor vehicle (1) and a current road bank (cp _FB ) of a curved road section (20) traveled by the motor vehicle (1),

- With a control unit (8), which with a lateral acceleration sensor (3), a yaw rate sensor (5) and a speed sensor (6) of the motor vehicle (1) for transmitting a respective measured instantaneous lateral acceleration or instantaneous speed to the control unit in communication can be brought,

- wherein the control unit (8) from chassis data and lateral dynamics data, which include the instantaneous lateral acceleration (a _y ^sensor ) or instantaneous speed (v _x ) of the motor vehicle (1), using the method according to one of the preceding claims the Current vehicle roll angle (φ _Α ) of the motor vehicle (1) and the current road-bank angle (<p _FB ) determined by the motor vehicle (1) curvy road section (20) determined.

Motor vehicle (1),

- with a device (7) according to claim 4,

- With a lateral acceleration sensor (3), a yaw rate sensor (5) and a speed sensor (6), each with the control unit (8) for transmitting a measured instantaneous lateral acceleration (a _y ), a current yaw rate (d / dt ψ) or instantaneous speed (v _y ) of the motor vehicle (1) are in communication connection.