DE102020206707A1 - Method for influencing the driving behavior of a motor vehicle while cornering and motor vehicle for carrying out the method - Google Patents

Abstract

The invention relates to a method for influencing the driving behavior of a motor vehicle (100) while cornering, whereby it is detected whether the motor vehicle (100) is in the driving state of cornering and whether a load change of the motor vehicle (100) takes place while cornering. The driving behavior is influenced as a function of the detected driving state. According to the invention, the driving behavior is influenced in the event of a load change at least also as a function of a driving profile that can be selected or selected by a vehicle driver in such a way that a load change reaction of the motor vehicle (100) to the load change occurs in its Effect is reduced or increased.

Description

The invention relates to a method for influencing the driving behavior of a motor vehicle while cornering with the features from the preamble of claim 1. The invention also relates to a motor vehicle for carrying out the method. Finally, the invention also relates to an additional device for installation in a motor vehicle.

From the EP 0 792 782 A1 a method for influencing the driving behavior of a motor vehicle while cornering with the features of the preamble of claim 1 has become known. Specifically, the method disclosed in this document is intended to ensure neutral driving behavior when cornering and simultaneously changing loads, namely from pulling to pushing mode. In the method, the operation of a vehicle system with a driven axle and a differential gear assigned to the driven axle is proposed. Wheel brakes are used to selectively brake individual wheels. Furthermore, a device for recognizing cornering is used. Another device is used to detect overrun operation and to generate a signal corresponding to the strength of overrun operation. When cornering, a wheel of the driven axle is braked as a function of the overrun signal generated in such a way that a counter yaw moment generated thereby can compensate for a yaw moment caused by cornering during overrun. To detect cornering, a differential speed of the wheels on the non-driven axle is determined, and a steering angle and / or the transverse acceleration of the motor vehicle are recorded.

Sports vehicles often have a so-called ESC Off mode (ESC = Electronic Stability Control) with which a vehicle stabilization device of the motor vehicle can at least partially be switched off or its functionality can be restricted. Depending on an existing chassis setting, a load change that occurs while cornering, which can be configured as a load change from pulling to pushing operation (so-called power-off), can under certain circumstances cause a driving situation that is not easy to handle for some vehicle drivers . In addition, understeering can occur in front-wheel drive vehicles when the load changes towards more propulsion or even when the load changes from pushing to pulling (so-called power-on), which does not match the character of the vehicle when driving in a sporty manner and also lead to difficult driving conditions can.

The present invention is based on the object of proposing a method for influencing the driving behavior of a motor vehicle with which, on the one hand, the driving experience for a vehicle driver when cornering can be intensified and, on the other hand, it is also possible to avoid difficult driving situations.

Another object of the invention is to provide a suitable motor vehicle for carrying out the method. Finally, the invention is also intended to propose a suitable additional device which can be installed in a motor vehicle and which can contribute to the implementation of the method.

The aforementioned objects are achieved by a method with the features of patent claim 1, by a motor vehicle with the features of patent claim 7 and by an additional device with the features of patent claim 11.

Advantageous designs or further developments can be found in the respective dependent claims.

The invention is based on a method for influencing the driving behavior of a motor vehicle while cornering, in which it is detected whether the motor vehicle is in the driving state of cornering and whether a load change of the motor vehicle takes place while cornering. The driving behavior is influenced as a function of the detected driving condition.

The invention now proposes that the influencing of the driving behavior in the event of a load change is carried out at least also as a function of a driving profile that can be selected or selected by a vehicle driver in such a way that the effect of a load change reaction of the motor vehicle to the load change is reduced or increased.

In contrast to the prior art, it is not only possible to compensate for a load change reaction, but rather a targeted influencing / change of the driving behavior takes place in accordance with an active specification by a vehicle driver. Thus, the influencing does not take place in a fixed, fixed, unchangeable manner, for example only as a reaction to a load change from pulling to pushing operation. Rather, the way in which driving behavior is influenced during cornering is designed to be extremely flexible.

A change in load within the meaning of the present invention is primarily intended to be a change in the longitudinal acceleration of the motor vehicle be understood. Such a change in load can be triggered, for example, by accelerating (actuating the accelerator pedal) or also by slowing down (releasing the accelerator pedal). The load change can also include a load change, namely from pulling to pushing operation or from pushing to pulling operation. Such load changes occur when the accelerator pedal is suddenly released after “accelerating” beforehand or when the accelerator pedal is suddenly actuated after the accelerator pedal has been released.

• • Erhöhung der Vielfalt des möglichen Fahrzeugführerlebnisses
• • höherer Fahrkomfort bei gestiegener Sicherheit
• • definiertere Abstimmbarkeit des grundsätzlichen Fahrverhaltens des Kraftfahrzeugs. Insbesondere kann ein notwendiger Kompromiss in der Fahrwerksgrundabstimmung zwischen Komfort und Stabilität einerseits sowie Sportlichkeit und Agilität andrerseits gelockert werden, so dass eine agilere Fahrwerksgrundabstimmung des Fahrwerks möglich ist.
• • Erhöhung der Stabilität des Kraftfahrzeugs und somit Hinausschieben eines Eingriffszeitpunktes eines ESC-Systems (ESC = Electronic Stability Control)

The procedure according to the invention enables the following advantages to be achieved:

• • Increasing the diversity of the possible vehicle driving experience
• • greater driving comfort with increased safety
• • more defined adaptability of the basic driving behavior of the motor vehicle. In particular, a necessary compromise in the basic chassis tuning between comfort and stability on the one hand and sportiness and agility on the other hand can be relaxed, so that a more agile basic chassis tuning of the chassis is possible.
• • Increasing the stability of the motor vehicle and thus postponing an intervention time of an ESC system (ESC = Electronic Stability Control)

According to a first further development of the invention, it is proposed that a coefficient of friction utilization of the motor vehicle be determined or derived before influencing the driving behavior on the basis of a detected lateral and / or longitudinal acceleration. The driving behavior is then influenced at least also as a function of the degree of utilization of the coefficient of friction.

mit

• F_R = übertragbare Haftreibung,
• F_N = auf die Fahrbahn wirkende Radlast
• µ_R = Reibwert (der Reibwert für die Materialpaarung Reifen/trockener Asphalt liegt in etwa zwischen 0,5 und 0,6.

This development is based on the consideration that a tire can only transfer a certain maximum amount of static friction to the road surface during operation of a motor vehicle due to physical principles. This amount is dependent on a wheel load acting on the roadway through the tire and on a coefficient of friction. The coefficient of friction in turn depends on the material pairing of car tires / road surface, as shown in the formula below: $${\text{F.}}_{\text{R.}}={\mathrm{\mu }}_{\text{R.}}\times {\text{F.}}_{\text{N}}$$

with

• F _R = transferable static friction,
• F _N = wheel load acting on the roadway
• µ _R = coefficient of friction (the coefficient of friction for the tire / dry asphalt material pairing is roughly between 0.5 and 0.6.

How high a utilization of the coefficient of friction turns out to be with existing lateral and / or longitudinal accelerations can be calculated on the basis of complicated, empirically determined formulas. However, this is basically known and therefore does not need to be further elaborated here.

It is essential, however, that such a coefficient of friction utilization factor is at least also taken into account when specifically influencing driving behavior. This enables a more precise coordination of the targeted influencing of the driving behavior with the respective driving state.

For example, resulting roll angles can be calculated from measured longitudinal and / or transverse accelerations of the motor vehicle, and axle or wheel loads that arise can be derived. With the help of an estimated coefficient of friction it can then be calculated how much of this estimated coefficient of friction is currently being used on the wheels due to the measured longitudinal and / or transverse accelerations. In other words, the coefficient of friction utilization is a measure of how close one is currently moving to the physical limit range of the vehicle's driving dynamics in a certain driving condition and how much “safety margin” remains until such a limit range would be reached through a possible intervention in the driving behavior .

The degree of influencing the driving behavior is therefore at least also dependent on the degree of utilization of the coefficient of friction.

In particular, it is expedient here that, as the degree of utilization of the coefficient of friction increases, the degree of influencing the driving behavior is reduced, at least with regard to a desired amplification of a load change reaction that is taking place.

If, for example, the motor vehicle tends to turn into the curve (oversteer) when the accelerator pedal is suddenly released and the wheel loads are shifted associated with it, the desired amplification of this load change reaction is reduced or even completely omitted when the motor vehicle is already in the Is close to its limit area, so the coefficient of friction has already been largely utilized.

This can prevent the motor vehicle from deliberately influencing the Driving behavior is actively maneuvered into an ESC mode, which should be avoided as a rule and is perceived as unpleasant by a vehicle driver.

According to another development of the method, a load change-related yaw moment of the motor vehicle is calculated on the basis of a detected lateral and / or longitudinal acceleration, a determined curve direction and on the basis of a physical data model of the motor vehicle stored in the motor vehicle. At least the dynamic driving behavior of the motor vehicle during cornering is preferably mapped by the physical data model or can be mapped as a result.

Taking into account the determined coefficient of friction utilization, the current driving speed and the selected driving profile, an additional yaw moment is calculated therefrom, through which the reaction yaw moment of the motor vehicle can be reduced or increased in its effect.

In particular, depending on the selected driving profile, one of several characteristic diagrams stored in the motor vehicle is applied, that is to say used. This means that the initially calculated reaction yaw moment, the existing coefficient of friction utilization and the driving speed serve as input variables in order to calculate the additional yaw moment as an output variable via the driving profile-related characteristic field.

Finally, as a function of the calculated additional yaw moment, at least one control signal for controlling one or more actuators is generated and / or output. In this way, the load change behavior of the motor vehicle when cornering can be influenced in a targeted and reliable manner.

When carrying out the method, it may well be the case that a calculated additional yaw moment can actually only be generated with the aid of one or more specific actuators. In one embodiment of the method, it will therefore be expedient for one or more suitable actuators to be selected from a total of available actuators on the basis of the calculated additional yaw moment and for the at least one control signal to be output to the selected actuator or actuators. In other words, the respective suitable actuator or actuators are arbitrated.

As mentioned at the beginning, the present invention is also intended to provide a motor vehicle for carrying out the method. Such a motor vehicle has sensors for detecting longitudinal and transverse accelerations, for detecting a steering angle and for detecting a driving speed. Commercially available acceleration sensors, angle sensors and wheel speed sensors, for example, are suitable for this purpose.

The motor vehicle is equipped with at least one additional device in which at least one physical data model of the motor vehicle for mapping its dynamic driving behavior while cornering is digitally stored. A yaw moment of reaction of the motor vehicle caused by load changes can be calculated on the basis of a detected longitudinal acceleration.

In addition, several characteristic maps are digitally stored in the additional device. These maps can be applied (i.e. applicable) on the basis of the calculated reaction yaw moment, on the basis of a determined coefficient of friction utilization and on the basis of a recorded driving speed in such a way that an additional yaw moment is calculated therefrom, which reduces or increases the effect of the reaction yaw moment can.

As a function of the calculated additional yaw moment, at least one control signal for controlling one or more actuators can be generated and output, by means of which or by which the additional yaw moment can be generated.

There is also at least one input device in the interior of the motor vehicle, via which the selection of a desired driving profile is possible, in such a way that, depending on the selected driving profile, one of the maps for calculating the additional yaw moment can be applied or is applied, i.e. is applicable or used will.

In an expedient embodiment of the motor vehicle, a driving dynamics control unit for general control of driving dynamics of the motor vehicle (i.e. not only while cornering) can be present in addition to an anti-lock device and a vehicle stabilization device. The driving dynamics control unit has at least one interface to sensors with which longitudinal and transverse accelerations, a steering angle and a driving speed of the motor vehicle can be detected. The driving dynamics control unit also has at least one interface to the at least one actuator (or to a control unit which controls it) with which the additional yaw moment can be generated.

The additional device described above is integrated into the driving dynamics control unit. That means the additional device and the driving dynamics Control units are combined in a common housing.

In contrast to this, however, it is also conceivable that a driving dynamics control unit for general control of driving dynamics of the motor vehicle is present in addition to an anti-lock device and a vehicle stabilization device, the additional device being designed as an independent device separate from the driving dynamics control unit . This means that the additional device is accommodated in a housing that can be mounted separately from the driving dynamics control unit.

In this case, the additional device is preferably connected via a separate network to at least the sensors for detecting longitudinal and transverse accelerations, for detecting a steering angle and for detecting a driving speed. There is also at least one signaling connection with the at least one actuator or with its associated control unit for generating the additional yaw moment. In this way, the maintainability or exchangeability of the additional device can be made easier.

In order to ensure that the additional yaw moment is generated as required at all times, the motor vehicle is preferably equipped with several actuators that are suitable for generating the additional yaw moment. The actuators can include brakes that can be controlled individually for each wheel and / or clutches that can be controlled individually for each wheel and / or an electronically controllable locking differential. As an alternative or in addition, it is also conceivable that the actuators are formed by an all-wheel drive with a controllable center differential or with a controllable center clutch. Alternatively or additionally, the actuators can be designed as active (that is to say individually controllable) shock absorbers.

The additional device has an arbitration unit in which the identity of a plurality of control units is stored, each of which is used to control one of the actuators. The identity of the control units can, for example, be specified in each case via a network address of a vehicle network to which the control units are connected via a data bus. A selection logic is stored in the arbitration unit with which one or more of the control units can be selected from the total number of known control units depending on the calculated additional yaw moment and with which an actuating signal can be output to the selected control unit or units.

Finally, the present invention is also intended to protect an additional device which can be installed in a motor vehicle described above. Such an additional device has a housing which is provided with at least one interface for direct or indirect data exchange with sensors which are used to detect longitudinal and transverse accelerations, to detect a steering angle and to detect a driving speed of a motor vehicle.

The interface can be used, for example, to connect to a data bus (for example CAN bus) or also to connect directly to the individual sensors via a subnetwork.

The housing of the additional device is also provided with at least one interface for direct or indirect communication with at least one control unit of an actuator of the motor vehicle, which is used to generate an additional yaw moment. Furthermore, the additional device is provided with at least one interface for the direct or indirect exchange of data with an input device for selecting a driving profile.

Furthermore, at least a physical data model for mapping the dynamic driving behavior of the motor vehicle during cornering is stored in the additional device. A yaw moment of reaction of the motor vehicle caused by load changes can be calculated on the basis of a detected longitudinal acceleration.

In addition, several characteristic maps are digitally stored in the additional device. These maps can be applied (i.e. applicable) on the basis of the calculated reaction yaw moment, on the basis of a determined coefficient of friction utilization and on the basis of a determined driving speed in such a way that an additional yaw moment is calculated therefrom, which reduces or increases the effect of the reaction yaw moment can.

The additional device is set up by means of this and by a control logic stored in it in such a way that it can be used to calculate the yaw moment reaction that occurs when cornering when there is a load change on the basis of the data exchange with the sensors. Building on this, the additional device can generate at least one control signal for at least one actuator with which the additional yaw moment can be generated.

The additional device can be developed in such a way that it has an arbitration unit in which the identity of a plurality of control units is stored, each of which is used to control an actuator which is suitable for generating an additional yaw moment. In the Arbitration unit stores a selection logic with which one or more of the control units can be selected from the total number of known control units as a function of the calculated additional yaw moment, a control signal being able to be output to each of these control units.

Preferred exemplary embodiments of the invention are shown in the figures and are explained in more detail in the following description with reference to the figures. This also makes further advantages of the invention clear. The same reference symbols, even in different figures, relate to the same, comparable or functionally identical components. Corresponding or comparable properties and advantages are achieved, even if a repeated description or reference is not made. The figures are not, or at least not always, to scale. In some figures, proportions or distances can be exaggerated in order to be able to emphasize features of an exemplary embodiment more clearly.

• 1 ein Kraftfahrzeug zur Durchführung des Verfahrens, während einer Kurvenfahrt,
• 2 ein Ablaufdiagramm zur Erläuterung des Verfahrens,
• 3 das Kraftfahrzeug gemäß 1, während einer Kurvenfahrt mit Erzeugung eines Zusatz-Giermomentes,
• 4 die nähere Darstellung eines Teilschrittes des Ablaufdiagramms gemäß 2,
• 5 die nähere Darstellung eines weiteren Teilschrittes gemäß Ablaufdiagramm aus 2,
• 6 die nähere Darstellung eines weiteren Teilschrittes gemäß Ablaufdiagramm aus 2,
• 7 die Darstellung eines Momentendiagramms zur Veranschaulichung denkbarer Momentenverläufe,
• 8 die Darstellung eines Funktionsschaubildes einer ESC-Einheit des Kraftfahrzeugs mit einer integrierten Zusatzvorrichtung zur Berechnung eines Zusatz-Giermomentes und
• 9 die Darstellung eines Funktionsschaubildes einer separaten Zusatzvorrichtung zur Berechnung des Zusatz-Giermomentes.

It show each schematically

• 1 a motor vehicle to carry out the procedure while cornering,
• 2 a flow chart to explain the process,
• 3 the motor vehicle according to 1 , during cornering with generation of an additional yaw moment,
• 4th the detailed representation of a sub-step of the flowchart according to 2 ,
• 5 the detailed representation of a further sub-step according to the flowchart 2 ,
• 6th the detailed representation of a further sub-step according to the flowchart 2 ,
• 7th the representation of a moment diagram to illustrate conceivable moment curves,
• 8th the representation of a functional diagram of an ESC unit of the motor vehicle with an integrated additional device for calculating an additional yaw moment and
• 9 the representation of a functional diagram of a separate additional device for calculating the additional yaw moment.

First of all, the 1 Referenced. In this figure is a motor vehicle 100 can be seen which is prepared for carrying out the method according to the invention. Only those elements are shown which are essential for an understanding of the invention.

The car 100 has an ESC unit (ESC = Electronic Stability Control) with which the driving stability of the motor vehicle 100 should be ensured. The functional structure of the ESC unit 1 will be explained in more detail later.

The ESC unit 1 is signaling with a data bus 13th connected, which can be designed for example as a CAN bus (CAN = Controller Area Network). To the data bus 13th are also acceleration sensors 2 , Wheel speed sensors 3 , a steering angle sensor 4th as well as a vehicle on-board system 8th with a corresponding input device 8a (e.g. touchscreen) connected for signaling purposes.

A driver of the motor vehicle 100 has about the input device 8a of the vehicle on-board system 8th Among other things, the possibility of selecting one from several offered driving profiles and thereby at least one driving dynamics of the motor vehicle 100 to specifically influence during cornering. This will be discussed in more detail later.

The car 100 also has front wheels VR and rear wheels MR on. The front and rear wheels VR , MR have actuators designed as brakes, in particular as disk brakes 6a to 6d on. The actuators 6a to 6d are through the ESC unit 1 via hydraulic lines 5 individually controllable. Each wheel can therefore be braked as required.

Alternatively or in addition, an actuator can also be used 7th be available, which is designed as an electronically controllable differential lock. This can also be done with the data bus 13th be connected in terms of signaling (indicated by dashed lines)

Alternatively or additionally, it is also conceivable that the motor vehicle 100 is provided with actuators, which are designed as an all-wheel drive train with clutches that can be controlled individually for each wheel (not shown). Alternatively or additionally, the motor vehicle 100 also be equipped with actuators that are designed as an all-wheel drive with a controllable center differential or with a controllable center clutch. Alternatively or additionally, the motor vehicle 100 can also be equipped with actuators designed as active (i.e. individually controllable) shock absorbers.

• Ein Fahrzeugführer betätigt in der Kurve schlagartig das Fahrpedal, beschleunigt also zusätzlich. Hierdurch entstehen Veränderungen in den Radlasten, welche zu einem Reaktions-Giermoment führen, welches bei einem beispielsweise frontangetriebenen Kraftfahrzeug kurvenauswärts gerichtet ist. Das Kraftfahrzeug 100 antwortet auf die Laständerung also mit einer Untersteuerung und treibt auf einer Trajektorie Tu in Richtung kurvenaußen.

In the figure shown, the motor vehicle is moving 100 at a certain speed while cornering on a desired trajectory T . Due to the design-related, dynamic driving behavior of the motor vehicle 100 The following driving states can now occur while cornering:

• A vehicle driver suddenly presses the accelerator pedal in the curve, i.e. accelerates additionally. This results in changes in the wheel loads which lead to a reaction yaw moment which, in a front-wheel drive motor vehicle, for example, is directed out of the curve. The car 100 responds to the load change with an understeer and drifts on a trajectory Do towards the outside of the curve.

If, on the other hand, the reverse load case occurs, i.e. if the vehicle driver suddenly releases the accelerator pedal, the motor vehicle answers 100 with a curve-turning, i.e. oversteering behavior and moves on a trajectory Door . The driver is forced to counter-steer.

The load changes described lead to changes in the longitudinal and / or transverse accelerations ax and ay which at an imaginary focal point 9 of the motor vehicle 100 attack and lead to the aforementioned changes or changes in the wheel loads.

With the aid of the method according to the invention, the vehicle driver should be able to determine the dynamic driving behavior of the motor vehicle 100 in the event of load changes when cornering, to specifically influence it according to his wishes.

Based on the in the 2 The main procedural steps should first be presented in the flowchart shown in the flowchart.

This takes place in one process step S1 a load change by the vehicle driver while cornering, which can be characterized, for example, by increased or reduced use of the accelerator pedal, by a change from pulling to pushing mode or by changing from pushing to pulling mode. This change in load induces a change in the longitudinal acceleration ax of the motor vehicle 100 (compare 1 ).

In one process step S2 changes the longitudinal acceleration ax to a wheel load change.

In one process step S3 a driving state of the motor vehicle is determined by a logic on the vehicle side 100 recognized. It is recognized, for example, whether the motor vehicle 100 is cornering, it is also recognized whether the motor vehicle 100 is in a right or left curve and at what speed the motor vehicle is 100 moved through the curve.

In order to respond in a suitable or desired manner to the respectively conceivable, longitudinal acceleration-dependent load change reaction (as already described), in a method step S4 an additional yaw moment is calculated.

Depending on the calculated additional yaw moment, in one process step S5 a control signal is generated and sent to one or more of the actuators 6a to 6d , 7 issued.

This ultimately leads to the fact that the actuator or actuators are adjusted 6a to 6d , 7 the desired additional yaw moment is generated. The self-steering behavior induced by the load change, that is to say the load change reaction of the motor vehicle, thus becomes 100 reduced or increased in their effect. The car 100 moves on a desired trajectory despite the change in load T (Process step S6 ).

Based on 3 the process is briefly outlined again using a load change that is characterized by a sudden actuation of the accelerator pedal ("accelerate") in the curve. The clarity are here with the motor vehicle 100 the individual elements (compare 1 ) no longer shown and numbered.

Due to the change in load, the motor vehicle 100 a reaction yaw moment MGR generated. The reaction yaw moment MGR is directed out of the curve, so that the motor vehicle 100 for understeering with a trajectory Do tends.

• • Es wird durch das Kraftfahrzeug ein Zusatz-Giermoment erzeugt, welches dem Reaktions-Giermoment MGR entgegenwirkt und somit die Laständerungsreaktion des Kraftfahrzeugs 100 in ihrer Wirkung vermindert. Beispielsweise können ein Zusatz-Giermoment MGZ1 oder ein Zusatz-Giermoment MGZ2 berechnet werden. Das Zusatz-Giermoment MGZ1 vermindert das Reaktions-Giermoment MGR soweit, dass dieses ausgeglichen wird. Das Zusatz-Giermoment MGZ2 gleicht die Wirkung der Laständerungsreaktion nur teilweise aus.
• • Es wird ein Zusatz-Giermoment MGZ3 erzeugt, welches in Richtung des Reaktions-Giermomentes MGR gerichtet ist. Hierdurch kann also die Laständerungsreaktion des Kraftfahrzeugs 100 in ihrer Wirkung sogar noch verstärkt werden.

Depending on which driving profile has now been selected by the vehicle driver, the following cases are conceivable:

• • An additional yaw moment is generated by the motor vehicle, which is the reaction yaw moment MGR counteracts and thus the load change reaction of the motor vehicle 100 diminished in their effect. For example, an additional yaw moment MGZ1 or an additional yaw moment MGZ2 be calculated. The additional yaw moment MGZ1 reduces the yaw moment of reaction MGR to the extent that this is compensated for. The additional yaw moment MGZ2 only partially offsets the effect of the load change response.
• • There is an additional yaw moment MGZ3 generated, which in the direction of the reaction yaw moment MGR is directed. As a result, the load change reaction of the motor vehicle can 100 their effect can even be enhanced.

Based on 4th is the procedural step S3 (compare 2 ), in which the driving condition of the motor vehicle 100 is captured, shown in more detail.

This takes place in one process step S3-1 first of all, a detection of the accelerations occurring during cornering when the load changes. The detection takes place specifically by the acceleration sensors 2 . With the help of the wheel speed sensors 3 becomes a traveling speed of the motor vehicle 100 recorded.

In one process step S3-2 it is determined whether the motor vehicle 100 is in a cornering, in particular in a right or left curve. This determination can be made, for example, with the aid of the steering angle sensor 4th and / or or also by determining the differential speed of the wheels.

With the help of the detected accelerations of the motor vehicle 100 and one in the motor vehicle 100 stored, estimated coefficient of friction is carried out on the vehicle side, an estimate of a momentary coefficient of friction utilization.

The coefficient of friction utilization is a measure of what percentage of that on the wheels VR , MR maximum transferable frictional force is currently transferred. In other words, it is a measure of how close you are to the dynamic, physically determined limit range of the motor vehicle 100 has already moved closer and how much leeway one still has, at least in the direction of further utilization of the coefficient of friction.

The calculation of such a coefficient of friction utilization is based on complex, empirical formulas and is known per se. It therefore does not need to be explained in more detail here.

Finally, in one process step S3-3 the yaw moment of reaction MGR calculated, which adjusts to a load change.

The calculation of the reaction yaw moment MGR takes place on the basis of a physical data model of the motor vehicle stored in the vehicle 100 , by means of which at least its dynamic driving behavior can be or is mapped during cornering.

Based on 5 will now be described in more detail, as in process step S4 (compare 2 ) an additional yaw moment is calculated in order to selectively control the driving behavior of the motor vehicle 100 , in particular to influence its load change reaction during cornering.

In a method step S4-1, a query is made as to which driving profile has been selected by the vehicle driver. It is conceivable, for example, that the vehicle driver has the option of using the input device 8a of the vehicle on-board system 8th , which can be formed for example by a touchscreen, to select “Comfort”, “Normal” and “Sport” under driving profiles.

Depending on the selected driving profile, this takes place in one process step S4-2a , S4-2b or S4-2c the application of one of several maps stored on the vehicle. The calculated reaction yaw moment serves as input variables for the application MGR , the recorded signals of the acceleration sensors 2 as well as the recorded driving speed, the determined coefficient of friction utilization and the determined curve type as auxiliary variables.

A driving profile-dependent additional yaw moment is derived from this in method step S4-3 MGZ (see also 7th ) calculated.

In a method step S4-4, a query is made as to whether the determined wheel value utilization factor in view of the additional yaw moment to be set MGZ has a limiting effect or not. In other words, it is queried whether the calculated additional yaw moment is MGZ in the direction of a higher utilization of the coefficient of friction or not. If so, takes place in the process step S4-5 a cap of the additional yaw moment to a certain limit value. This should be done later using the 7th will be explained in more detail.

the 6th shows the process step S5 again in a closer way. In a method step S5-1, it is first asked which of the actuators 6a to 6d , 7 up-to-date available, which are therefore error-free and functional.

In one process step S5-2 it is then queried by which or by which of the available actuators the calculated additional yaw moment MGZ (best) can be realized.

According to the result, one or more of the actuators is selected in method step S5-3 6a to 6d , 7.

The procedural step S5 thus also includes arbitration, ie a selection of suitable actuators.

Based on 7th a diagram is shown in which a calculated additional yaw moment MGZ over a load change-related yaw moment of reaction MGR is applied. Depending on the type of curve (right or left curve), the moments can act in different directions (+, -).

• So sind eine Momentenkennlinie N für das ausgewählte Fahrprofil „Normal“, eine Momentenkennlinie K für das ausgewählte Fahrprofil „Komfort“ und zwei Momentenkennlinien SP1 und SP2 für ein ausgewähltes Fahrprofil „Sport“ eingezeichnet.

On the basis of a driving profile selection carried out by the vehicle driver, you can enter for example, the following relationships occur in the torque curves:

• Such are a torque curve N for the selected driving profile "normal", a torque characteristic K for the selected "Comfort" driving profile and two torque characteristics SP1 and SP2 drawn in for a selected “Sport” driving profile.

It can be seen that with the torque characteristic K for each calculated reaction yaw moment MGR an opposing additional yaw moment MGZ is calculated, which is the reaction yaw moment MGR counteracts and completely compensates for this.

With the torque curve N also becomes at every reaction yaw moment MGR an opposite additional yaw moment MGZ calculated. However, the magnitude of this is less than the yaw moment of reaction MGR and cannot compensate for this.

Finally, in the case of the torque curve SP1 for each calculated reaction yaw moment MGR an additional yaw moment acting in the same direction MGZ calculated. In the case of the torque curve SP1 it is assumed, for example, that a momentary coefficient of friction utilization RA in the amount of 50 percent. It is at this coefficient of friction utilization RA So there is still room for improvement, so that the coefficient of friction is increased by increasing the yaw moment of reaction MGR can definitely be further exploited.

With the torque curve SP2 on the other hand, the coefficient of friction utilization is already significantly higher RA assumed to be 90 percent. Here the torque characteristic is much flatter because there is only little room for improvement until the maximum possible degree of coefficient of friction is fully utilized, and there is thus only a short distance from an ESC intervention that then takes place.

With the help of 8th should now the ESC unit 1 be considered more closely. The ESC unit 1 includes an anti-lock unit 10 , a stabilization unit 11th and a driving dynamics control unit 12th . The anti-lock unit 10 comprises a known ABS (anti-lock braking system) and, as is known, prevents the wheels from locking during braking and thus further steering ability of the motor vehicle despite braking 100 preserved. The stabilization unit 11th ensures that the motor vehicle 100 remains stable within physical limits in all driving situations. The driving dynamics control unit 12th is not used for driving safety or driving stabilization of the motor vehicle 100 , but rather for general, active regulation or influencing of the driving dynamics of the motor vehicle 100 , also when cornering, as already described above.

The driving dynamics control unit 12th an auxiliary variable supply unit 12a , an additional device 12b and an actuator interface 12c on.

The additional device 12b in turn comprises a storage unit 122 , a unit of logic 123 and an arbitration unit 124 .

Based on sensor signals 120 (e.g. acceleration values, wheel speeds, steering angle) and other auxiliary variables 121 (Utilization of the coefficient of friction RA , Driving speed) is stored in the logic unit 123 based on one in the storage unit 122 stored, physical data model from the motor vehicle 100 and on the basis of an applied map that is dependent on the selected driving profile, the reaction yaw moment MGR as well as the additional yaw moment MGZ (as already explained) calculated.

The arbitration unit 124 choose from the actuators you know 6a to 6d , 7 (compare also 1 ) selects the appropriate ones and generates one or more control signals 125 for those from the actuators 6a to 6d , 7 selected actuators, for example actuators 6a and 7. The control signals 125 can later via the actuator interface 12c are output to the respective actuators.

In contrast to this exemplary embodiment, one in the ESC unit 1 integrated additional device 12b , it is also conceivable in the motor vehicle 100 an additional device with the same effect but separate 14th to be installed (in 1 indicated by dashed lines).

As with 9 is shown, has the separate additional device 14th also a storage unit 140 , a unit of logic 141 and an actuator interface 142 on.

The additional device 14th is housed in a separate housing as an assemblable unit. It can interface with the data bus 13th be connected. However, it is also conceivable that the additional device 14th over a subnetwork 15th directly with the sensors 2 , 3 and 4th can communicate.

Based on the sensors 2 , 3 and 4th The additional device calculates the received sensor signals 14th in the logic unit 141 based on one in the storage unit 140 stored, physical data model of the motor vehicle 100 (as already described) and the driving profile-dependent maps stored there, in turn, when the load changes Additional yaw moment desired during cornering MGZ . In its own actuator interface 142 , which also includes an arbitration unit, not shown, are then in turn control signals for selected actuators or control devices in the motor vehicle 100 available actuators 6a to 6d and 7 selected.

A communication of the additional yaw moment calculating device 14th with the mentioned actuators 6a to 6d , 7 can also be over a subnetwork 16 done, with the subnetworks 15th and 16 for example, can be designed as a LIN bus (LIN = Local Interconnect Network).

List of reference symbols

1

ESC unit

2

Accelerometers

3

Wheel speed sensors

4th

Steering angle sensor

5

Hydraulic lines

6a-6d

Actuators (brakes)

7th

Actuator (electronically controllable differential lock)

8th

Vehicle on-board system

8a

Input device

9

main emphasis

10

Anti-lock unit (ABS)

11

Stabilization unit

12th

Driving dynamics control unit

12a

Auxiliary quantities provision unit

12b

integrated additional device

12c

Actuator interface

13th

Data bus (CAN)

14th

separate additional device

15th

Subnetwork (LIN)

16

Subnetwork (LIN)

100

Motor vehicle

120

Sensor signals

121

Auxiliary variables

122

Storage unit

123

Logic unit

124

Arbitration unit

125

Control signals

140

Storage unit

141

Logic unit

142

Actuator interface

ay

Lateral acceleration

ax

Longitudinal acceleration

K

Torque characteristic with the selected driving profile "Comfort"

MGR

Reaction yaw moment

MGZ

Additional yaw moment

MGZ1

compensating additional yaw moment

MGZ2

reducing additional yaw moment

MGZ3

reinforcing additional yaw moment

N

Torque characteristic with the selected driving profile "Normal"

RA

Coefficient of friction utilization

SP1, SP2

Torque characteristics with the "Sport" driving profile selected

S1-S6

Procedural steps

S3-1 to S3-3

Procedural steps

S4-1 to S4-5

Procedural steps

S4-2a to S4-2c

Procedural steps

S5-1 to S5-3

Procedural steps

T

desired trajectory

Do

Understeer trajectory

Door

Oversteer trajectory

VR

Front wheels

MR

Rear wheels

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 0792782 A1 [0002]

Claims (12)

Method for influencing the driving behavior of a motor vehicle (100) while cornering, whereby it is detected whether the motor vehicle (100) is in the driving state of cornering and whether a load change of the motor vehicle (100) takes place during cornering, and depending on the detected Driving state an influencing of the driving behavior is carried out, characterized in that the influencing of the driving behavior in the event of a load change is carried out at least also as a function of a driving profile that can be selected or selected by a vehicle driver in such a way that a load change reaction of the motor vehicle (100) to the load change is effective is decreased or increased. Procedure according to Claim 1 or 2 , characterized in that prior to influencing the driving behavior on the basis of a detected lateral and / or longitudinal acceleration (ay, ax), a coefficient of friction utilization (RA) of the motor vehicle (100) is determined or derived, the influencing of the driving behavior at least also as a function of the Coefficient of friction utilization (RA) takes place. Procedure according to Claim 2 , characterized in that the degree of influencing the driving behavior is at least also dependent on the coefficient of friction utilization (RA). Procedure according to Claim 3 , characterized in that as the coefficient of friction utilization (RA) increases, the degree of influencing the driving behavior is reduced, at least with regard to a desired reinforcement of a load change reaction that is taking place. Method according to one of the preceding Claims 2 until 4th , characterized in that on the basis of a detected longitudinal acceleration (ax), a determined curve direction and a physical data model of the motor vehicle (100) stored in the motor vehicle (100) a load change-related reaction yaw moment (MGR) of the motor vehicle (100) is calculated and from this under Taking into account the determined coefficient of friction utilization (RA), the driving speed and the selected driving profile, an additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) is calculated, through which the reaction yaw moment (MGR) of the motor vehicle (K) reduces or increases its effect can be, with at least one control signal (125) for controlling one or more actuators (6a-6d, 7) being output as a function of the calculated additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3). Procedure according to Claim 5 , characterized in that on the basis of the calculated additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) one or more suitable actuators (6a-6d, 7) are selected from a total of available actuators (6a-6d, 7) and the at least one control signal (125) is output to the selected actuator (6a-6d, 7) or to the selected actuators (6a-6d, 7). Motor vehicle (100) for performing the method according to one of the Claims 1 until 6th , with sensors (2, 3, 4) for detecting longitudinal and transverse accelerations (ax, ay), for detecting a steering angle and for detecting a driving speed, and with at least one additional device (12b, 14) in which at least one physical data model of the motor vehicle (100) is stored for mapping its dynamic driving behavior during cornering, so that a load change-related yaw moment (MGR) of the motor vehicle (100) can be calculated on the basis of a detected longitudinal acceleration (ax), with the additional device (12b, 14 ) Furthermore, several maps are stored, which can be applied on the basis of the calculated reaction yaw moment (MGR), on the basis of a determined coefficient of friction utilization (RA) and on the basis of a recorded driving speed in such a way that an additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) is calculated by which the effect of the reaction yaw moment (MGR) of the motor vehicle (100) is reduced or increased can rden, depending on the calculated additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) at least one actuating signal (125) for controlling one or more actuators (6a-6d, 7) can be output by which or by which the additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) can be generated, wherein At least one input device (8a) is present in the interior of the motor vehicle (100), via which the selection of a desired driving profile is possible, in such a way that, depending on the selected driving profile, one of the maps for calculating the additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) can be applied. Motor vehicle (100) according to Claim 7 , characterized in that there is a driving dynamics control unit (12) for controlling driving dynamics of the motor vehicle (100) in addition to an anti-lock device (10) and a vehicle stabilization device (11), the driving dynamics control unit (12) has at least one interface to sensors (2, 3, 4) with which longitudinal and transverse accelerations (ax, ay), a steering angle and a driving speed can be recorded and at least one actuator interface (12c) to the at least one actuator (6a-6d, 7), with which the additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) can be generated, the additional device (12b) being integrated into the driving dynamics control unit (12). Motor vehicle (100) according to Claim 7 , characterized in that a driving dynamics control unit (12) for controlling a driving dynamics of the motor vehicle (100) in addition to an anti-lock device (10) and a vehicle stabilization device (11) is present, the additional device (14) as an independent device , is formed from the driving dynamics control unit (12) separate device and via a separate network (15) at least with the sensors (2, 3, 4) for detecting longitudinal and transverse accelerations (ax, ay), for detecting a steering angle and for detecting a driving speed and also with at least one actuator (6a-6d, 7) for generating the additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) is connected for signaling purposes. Motor vehicle (100) according to one of the preceding claims, characterized in that there are several actuators (6a-6d, 7) which are suitable for generating the additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3), the actuators (6a -6d, 7) individually controllable brakes and / or individually controllable clutches and / or an electronically controllable locking differential and / or an all-wheel drive with a controllable center differential or with a controllable center clutch and / or individually controllable shock absorbers, the additional device (12b, 14) a Arbitration unit (124) in which the identity of a plurality of control units is stored, each of which is used to control one of the actuators (6a-6d, 7) Control units depending on the calculated additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) one or more of the control units can be selected d with each of which a control signal (125) can be output to the selected control unit or units. Additional device (14) for installation in a motor vehicle (100) according to one of the Claims 7 until 10 , wherein the additional device (14) has a housing which is equipped with at least one interface for direct or indirect data exchange with sensors (2, 3, 4) for detecting longitudinal and transverse accelerations (ax, ay), for detecting a steering angle and for Detection of a driving speed of the motor vehicle (100) is provided, the housing of the additional control device (14) also having at least one interface for direct or indirect communication with at least one control unit of an actuator (6a-6d, 7) of the motor vehicle (100) for generating an additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) and with at least one interface for direct or indirect data exchange with an input device (8a) for selecting a driving profile, and the additional device (14) being provided with at least one stored therein , physical data model for mapping the dynamic driving behavior of the motor vehicle (100) while cornering, durc h The characteristic diagrams stored in it and a control logic stored in it are set up in such a way that the additional device (14), due to the data exchange with the sensors (2, 3, 4), produces a reaction yaw moment (MGR) when cornering when the load changes of the motor vehicle (100) can be calculated, an additional yaw moment (MGZ; MGZ; MGZ1, MGZ2, MGZ3) can be calculated, by means of which the effect of the reaction yaw moment (MGR) can be reduced or increased and from this at least one control signal for at least one actuator (6a-6d, 7) can be generated by the additional device (14), with which the additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3) can be generated. Additional device (14) after Claim 11 , characterized in that it has an arbitration unit in which the identity of several control units is stored, each of which is used to control an actuator (6a-6d, 7) which is used to generate an additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3. ) is suitable, whereby a selection logic is stored in the arbitration unit, with which one or more of the control units can be selected from the total number of known control units depending on the calculated additional yaw moment (MGZ; MGZ1, MGZ2, MGZ3), with each of these control units a control signal can be output.

Images