DE102018210309B4 - Motor vehicle and method for operating a motor vehicle - Google Patents

Abstract

Motor vehicle (2) having a steering system (4), a sensor system (6) for monitoring the surroundings and a control and evaluation unit (8), the control and evaluation unit (8) being set up to evaluate sensor data from the sensor system (6) in this way that a surrounding object (10) is recognized in the surrounding area and a lateral distance (a) to the surrounding object (10) is monitored, characterized in that the control and evaluation unit (8) is set up to control the steering system (4) in such a way that that when the lateral distance (a) falls below a first limit value (a1), a steering ratio is specified and that the steering ratio is increasingly reduced as the value falls below the first limit value (a1).

Description

The invention relates to a motor vehicle having a steering system, a sensor system for monitoring the surroundings and a control and evaluation unit, the control and evaluation unit being set up to evaluate sensor data of the sensor system in such a way that an object in the surroundings is recognized and a lateral distance to it Surrounding object is monitored. Such a motor vehicle is for example from the DE 2010 010 489 A1 refer to. The invention also relates to a method for operating such a motor vehicle.

The variety of driver assistance systems and the spread of driver assistance systems are increasing from vehicle generation to vehicle generation. Corresponding driver assistance systems are used in some cases to support a vehicle driver, driver or user in driving a motor vehicle and, for example, to provide them with information relevant to driving the vehicle. Other driver assistance systems are designed to enable partially or fully autonomous vehicle guidance and accordingly to partially or completely take over the guidance of a motor vehicle.

Among other things, driver assistance systems are known which support a vehicle driver in keeping a motor vehicle in a lane or lane delimited by markings or which are designed to keep a corresponding vehicle in a corresponding lane by partially or fully autonomous vehicle guidance. For such driver assistance systems, the terms lane departure warning and lane assistant are common and examples of such driver assistance systems are taken from EP 2 032 406 B1 and the WO 2006/037445 A1 refer to.

In addition, driver assistance systems are, for example, from the EP 1 898 232 B1 and the US 2009/0138201 A1 known, which are designed to detect possible side collisions and support a vehicle driver, for example, in an intended change of lane.

Further systems to assist with driving the vehicle are from the DE 198 30 548 A1 , the DE 10 2004 037 298 A1 , the DE 10 2015 200 171 A1 and the DE 10 2007 027 495 A1 known.

The object of the present invention is to specify a motor vehicle with an advantageous driver assistance system and an advantageous method for operating such a motor vehicle.

This object is achieved by a motor vehicle with the features of claim 1 and by a method with the features of claim 10. Advantageous configurations with expedient developments of the invention are specified in the dependent claims. The advantages and preferred refinements cited with regard to the motor vehicle can also be applied to the method and vice versa.

The motor vehicle according to the invention is designed, for example, as a passenger car, truck or omnibus and has a steering system which is expediently controllable or controllable and typically designed as a so-called active steering system.

Here, a steering wheel is usually part of the steering system, which enables a vehicle driver, driver, operator or user to interact with the steering system. The interaction takes place by specifying a rotational position of the steering wheel by the respective vehicle driver and in particular by turning the steering wheel starting from a zero position, with a steering torque typically being applied by the vehicle driver to specify a rotational position or to turn the steering wheel. The rotational position of the steering wheel, or the steering angle for short, is clearly linked in many operating situations or operating states of the motor vehicle with a rotational position of the wheels of the motor vehicle connected to the steering system and rotatable by the steering system, i.e. with a wheel angle, so that in these cases typically a clear In particular, there is a relationship between the rotational position of the wheels and the rotational position of the steering wheel that is independent of measured values. The relationship between the rotational position of the wheels and the rotational position of the steering wheel is referred to as the steering ratio. This means that the steering ratio is proportional to the ratio between the rotational position of the wheels and the rotational angle of the steering wheel.

The steering wheel represents only one example of a possible input device or input element for direction control and accordingly the inventive principle described below can also be transferred to other input devices, for example an input device which is designed as a type of joystick. However, because of the greater prevalence, a steering wheel is always assumed below as the input device.

The motor vehicle furthermore has a sensor system for monitoring the surroundings of the motor vehicle, the sensor system being set up to acquire information about the surroundings of the motor vehicle and to generate Sensor data based on the information collected. That sensor system is designed, for example, as an optical system, as a radar system, as a sound system or as a hybrid system, with at least two different sensor units being used in the case of a hybrid system, which are based on different measuring principles, for example one optical system as one sensory unit and a radar system as a further sensory unit of the hybrid system.

In addition, a control and evaluation unit is part of the motor vehicle, the control and evaluation unit being set up to evaluate sensor data of the sensor system in at least one operating mode in such a way that an object in the vicinity, for example another motor vehicle or a wall of a tunnel, is recognized in the vicinity of the motor vehicle and a lateral distance to the surrounding object is monitored. For the purposes of this application, the lateral distance is to be understood as the distance between the motor vehicle and the surrounding object in a transverse direction transverse to a longitudinal direction of the motor vehicle, the longitudinal direction of the motor vehicle typically extending in a direction from a rear to a front of the motor vehicle.

The control and evaluation unit is also expediently set up to recognize all relevant environmental objects in the vicinity of the motor vehicle and within the sensor area of the sensor system in the at least one operating mode based on the sensor data and to monitor the respective lateral distances to these relevant environmental objects. In this case, those objects in the surroundings of the motor vehicle are usually viewed as relevant surroundings objects which have a predetermined minimum size, that is to say which have a certain extent transverse to the transverse direction. As a result, other road users in particular are then recognized as relevant objects in the surroundings, for example other motor vehicles, cyclists and pedestrians. In addition, however, obstacles are also preferably recognized as relevant environmental objects, for example a crash barrier or guard rail or a wall of a tunnel.

In the further explanations, however, for the sake of simplicity, it is mostly assumed that only one environmental object, in particular a motor vehicle, is recognized and accordingly only one environmental object is located in the sensor area of the sensor system. Nonetheless, the inventive principle described here can always be easily transferred to situations in which several objects in the vicinity are recognized by the person skilled in the art, in which case the object in the vicinity that has the smallest lateral distance to the motor vehicle is always of the greatest importance. If, therefore, the following simply refers to an environmental object or an environmental object, what is meant is always the environmental object with the smallest lateral distance from the motor vehicle, for all cases in which several environmental objects are recognized.

Furthermore, the control and evaluation unit is set up in such a way that it controls the steering system in the at least one operating mode in such a way that if the lateral distance to the recognized object in the vicinity or to the closest recognized object in the vicinity is undershot, a steering ratio is specified and that the The steering ratio is increasingly reduced as the value falls below the first limit value. The control and evaluation unit is also preferably set up in such a way that it controls the steering system in the at least one operating mode in such a way that a counter-steering torque is generated when the first limit value is undershot, and that the counter-steering torque is increasingly increased as the value falls below the first limit value.

In this operating mode of the control and evaluation unit, a driver assistance function is then active that influences the steering system depending on the lateral distance to the object in the vicinity or the closest object in the vicinity, i.e. to the object in the vicinity that is the smallest distance in the transverse direction from the motor vehicle. The motor vehicle then has a driver assistance system by means of which that driver assistance function, or assistance function for short, is implemented. The driver assistance function also preferably influences the steering system as a function of a steering torque applied by the vehicle driver, which is then applied to the steering wheel. The counter-steering torque in turn then counteracts this steering torque in particular.

The embodiment in which a counter-steering torque is specified and varied also relates primarily to steering systems with a steering motor, with steering systems of this type applying a corresponding counter-steering torque and possibly also a base counter-steering torque with the aid of the steering motor. The version in which a steering ratio is specified and varied, on the other hand, relates primarily to steering systems with superimposed steering or with decoupled steering, for example so-called "drive-by-wire" systems. In these cases, a counter-steering torque is typically not generated and varied; instead, the steering ratio is adapted, that is, the relationship between the rotational position of the one connected to the steering system and the wheels of the motor vehicle that can be rotated by the steering system and the rotational position of the steering wheel.

The assistance function described can also preferably be activated and deactivated by a vehicle driver, with a corresponding activation or deactivation being able to be carried out, for example, via a switch, button or via a menu selection of an on-board system or on-board computer.

In addition, various design variants are provided for the assistance function and, depending on the application, different design variants are implemented accordingly and implemented in the motor vehicle. A distinction must first be made between two types of design variants. The first type involves design variants of the assistance function that support a vehicle driver in driving the motor vehicle. With such design variants, control over the vehicle guidance and thus also the responsibility for the vehicle guidance remains in the hands of the vehicle driver. In the second type of variant, however, the assistance function realizes partially or fully autonomous vehicle guidance so that the vehicle driver, if he activates and uses a corresponding assistance function, relinquishes control of the vehicle guidance at least partially or completely. Put simply, in the case of the first type of embodiment variant, the vehicle driver can quasi overrule the assistance function at any time, whereas in the case of the second type of embodiment variant, a corresponding assistance function overrides the vehicle driver as long as the assistance function is activated.

Furthermore, an embodiment of the motor vehicle is advantageous in which the control and evaluation unit is set up to control the steering system in such a way that the counter-steering torque is essentially continuously increased as the first limit value continues to fall, or that the steering ratio increases as the value falls below the first limit value is essentially continuously increasingly reduced. In the simplest case, there is a linear relationship between the change in the counter-steering torque and the change in the undershooting of the first limit value for the lateral distance from the surrounding object. However, a relationship that can be described by a polynomial of the nth degree or an exponential relationship is preferred.

Alternatively, the control and evaluation unit is set up to control the steering system in such a way that the counter-steering torque is increasingly increased in several discrete steps as the value falls below the first limit value, or that the steering ratio increases in several discrete steps as the value falls below the first limit value is reduced.

In particular, if an embodiment variant of the assistance function according to the first type is to be implemented, it is further advantageous if the control and evaluation unit is set up to control the steering system in such a way that the counter-steering torque when a predetermined second, smaller limit value for the lateral distance is undershot is kept essentially constant with increasing undershoot or that, when undershooting the second, smaller limit value for the lateral distance, the steering ratio is kept constant with increasing undershoot.

In particular in the case of an embodiment variant according to the first type, a maximum value for the counter-steering torque or a minimum value for the steering ratio is therefore preferably specified. The two limit values are then expediently selected in such a way that a vehicle driver, based on his expected skills, is able at any time to counteract the intervention of the control and evaluation unit in the steering system and to overcome an associated hurdle.

In other words, in such an embodiment variant, the vehicle driver who is holding the steering wheel feels, for example, additional steering resistance when the motor vehicle falls below the first limit value for the lateral distance to the surrounding object and that the steering resistance increases increasingly due to the increasing counter-steering torque when the motor vehicle falls below the first limit value increasingly. Nonetheless, based on his expected abilities, the vehicle driver is in this case always able to apply a steering torque which overcomes the steering resistance and is therefore greater than the counter-steering torque. In this case, the increasing counter-steering torque merely draws the driver's attention to the fact that the motor vehicle is approaching an object in the surroundings, without this taking away control of the vehicle guidance from the vehicle driver. This means that the vehicle driver continues to decide in which direction the motor vehicle is to be steered, even if this results in a further approach to the surrounding object. As already explained above, this applies in particular in the case of an embodiment variant of the assistance function according to the first type.

The situation is similar in the case of the varying steering ratio. In this case, however, the vehicle driver typically does not have to apply a higher steering torque in order to counteract the intervention of the control and evaluation unit in the steering system when the value falls below the first limit value; instead, the vehicle driver must turn the steering wheel more strongly. This means that the driver of the vehicle is required to vary the angle of rotation of the steering wheel to a greater extent.

An embodiment of the motor vehicle in which the control and evaluation unit is set up to control the steering system in such a way that falling below the first limit value or a predetermined second, smaller limit value for the lateral distance is also advantageous is advantageous. In this case, a variant embodiment of the assistance functions of the second type is then typically implemented. For this purpose, in particular, a counter-steering torque is generated that a vehicle driver cannot overcome, since the expected skills of a vehicle driver are not sufficient to apply a sufficiently large steering torque, which is greater than the counter-steering torque.

More preferably, a counter-steering torque is specified by the control and evaluation unit, by means of which the lateral distance to the surrounding object is kept constant at the value of the first limit value or the second, smaller limit value, as soon as the second, smaller limit value is reached, in particular independently whether the vehicle driver applies a steering torque against the counter-steering torque or not. In other words, in this case the counter-steering torque is preferably adapted to a steering torque generated by the vehicle driver in order to quasi overrule the vehicle driver, regardless of how large the steering torque opposite the counter-steering torque is that the vehicle driver applies.

In an analogous manner, the vehicle driver is then quasi overruled when the steering ratio is adjusted, with the steering ratio being adapted to the steering movements of the vehicle driver by the control and evaluation unit by activating the steering system. Depending on the variant, the steering ratio is adjusted if necessary so that the steering ratio is also reversed in extreme cases, so that, for example, the driver steers to the right and the motor vehicle still drives to the left, for example in order to maintain a constant lateral distance in a left turn to hold a surrounding object.

In such a variant of the assistance functions, the intervention of the control and evaluation unit in the steering system only prevents the lower or the first or the second, smaller limit value for the lateral distance from being undershot, whereas the vehicle driver is still able to target the motor vehicle to steer in the opposite direction in order to increase the lateral distance to the surrounding object again in a targeted manner. I. E. So that in this case a steering action by the vehicle driver is typically canceled by the intervention of the control and evaluation unit in the steering system when the vehicle driver tries to steer in the direction of the surrounding object, whereas a steering action by the vehicle driver is permitted when the vehicle driver drives the motor vehicle steers away from the surrounding object.

Furthermore, an embodiment variant in which a mixture of both types of embodiment variants of the assistance function is implemented is advantageous. The assistance function then preferably acts between the first limit value and the second, smaller limit value in the manner of the first type and, when the second, smaller limit value is reached, in the manner of the second type. This means that if the first limit value is not reached, the vehicle driver initially only receives feedback or information in the form of additional steering resistance and that the assistance function only prevents the lateral distance from being further reduced by the assistance function when the second, lower limit value is reached by overriding the driver.

The above-described modes of operation of the implementation variants of the assistance functions function in principle regardless of whether the motor vehicle approaches an object in the vicinity from the earth system or whether the object in the vicinity, for example another motor vehicle, approaches the motor vehicle from the side.

This also means that in the case of the implementation of the second type of embodiment variant of the assistance function, a type of evasive function is typically also implemented, which the motor vehicle automatically evades when the surrounding object approaches too far. If the control and evaluation unit, by activating the steering system, prevents the first or second, smaller limit value for the lateral distance from being undershot and the surrounding object moving towards the motor vehicle, this results in an evasive movement of the motor vehicle in a lateral direction from the surrounding object. For such cases in particular, it is then further preferred that the sensor system also recognize road markings and monitor lateral distances from the road markings. If then, for example, the lateral distance to one falls below If the lane marking on the side of the motor vehicle opposite the object in the vicinity sets a predetermined lower limit, the motor vehicle is preferably automatically either braked or accelerated by the control and evaluation unit.

If, on the other hand, the first type of embodiment variant of the assistance function is implemented, the control and evaluation unit is preferably set up to control the steering system independently of possibly existing lane markings and in particular independently of a lateral distance to a lane marking, at least independently of a lateral distance to a lane marking on the same Side like the surrounding object.

Furthermore, it is useful if the control and evaluation unit is set up to control the steering system in such a way that the counter-steering torque is or is superimposed on a base counter-steering torque dependent on a rotational position of the steering wheel, or that the steering ratio is based on a base dependent on the rotational position of the steering wheel - Steering ratio is or will be superimposed. The basic counter-steering torque or basic steering ratio are usually independent of the lateral distance to an object in the vicinity and thus also independent of whether a corresponding assistance function is currently active or not.

It should be borne in mind that current steering systems are designed, for example, in such a way that the steering wheel can only be rotated from its zero position with the aid of a steering torque applied by a vehicle driver, and that if the steering wheel is rotated from the zero position, at least while driving the Motor vehicle builds up a basic counter-steering torque, which moves the steering wheel back into the zero position, provided that the basic counter-steering torque is not counteracted by the driver of the vehicle (straight-line stability).

Such a basic counter-steering torque is used in particular to specify a basic steering resistance. The basic steering resistance is a steering resistance common in current steering systems and typically only dependent on the rotational position of the steering wheel, which is intended to give the vehicle driver haptic feedback about cornering and the contact between tires and road and in this way convey a certain driving experience.

According to a further advantageous embodiment variant, the motor vehicle has a receiving device for receiving auxiliary data which are sent by the object in the vicinity. In addition, the control and evaluation unit is then set up to evaluate the auxiliary data in such a way that the surrounding object is recognized and a lateral distance to the surrounding object is monitored. Those auxiliary data are used, for example, to supplement the sensor data of the sensor system of the motor vehicle and / or to verify the lateral distances determined by means of the sensor data of the sensor system. Corresponding auxiliary data contain, for example, sensor data from a sensor system of another motor vehicle.

The motor vehicle also preferably has a transmission device which is set up to send auxiliary data, the auxiliary data usually being based on the sensor data or comprising sensor data and typically having information on the recognized object in the vicinity and on the lateral distance from the object in the vicinity. In particular, if the surrounding object is a further motor vehicle, these auxiliary data can then be used in the further motor vehicle in an analogous manner, at least if the further motor vehicle has comparable equipment with which an assistance function of one of the types described above is implemented.

• 1 in einer Blockschaltbilddarstellung ein Kraftfahrzeug; und
• 2 in einer Draufsicht das Kraftfahrzeug und ein weiteres Kraftfahrzeug in einer Verkehrssituation.

Further advantages, features and details of the invention emerge from the claims, the following description of preferred embodiments and on the basis of the schematic drawings. Show:

• 1 a motor vehicle in a block diagram representation; and
• 2 in a top view the motor vehicle and another motor vehicle in a traffic situation.

An example described below and in 1 Motor vehicle shown in a block diagram 2 has a steering system 4th with a steering wheel, a sensor system 6th as well as a control and evaluation unit 8th on. With the help of the sensor system 6th and the control and evaluation unit 8th In this case, several driver assistance systems with various assistance functions in the motor vehicle are preferred 2 realized so that neither the sensor system 6th nor the control and evaluation unit 8th can be clearly assigned to a single one of these driver assistance systems.

The sensor system is independent of this 6th for monitoring the surroundings of the motor vehicle 2 set up and thus for the acquisition of information about the environment of the motor vehicle 2 , with sensor data being generated during operation on the basis of the information recorded. The control and evaluation unit 8th in turn, the sensor data of the sensor system is set up 6th to be evaluated in at least one operating mode in such a way that an environmental object, which is in the surroundings and in the sensor area of the sensor system 6th is located, is detected and a lateral distance a to the surrounding object is monitored as long as the surrounding object is in the surroundings and in the sensor area of the sensor system 6th is located.

In the following, it is assumed that the surrounding object is a further motor vehicle 10 acts, as in the case of the traffic situation in 2 is sketched. Furthermore, for the sake of simplicity, only one environmental object in the surroundings of the motor vehicle is used below 2 went out. The inventive principle explained here can, however, easily be transferred to cases with several surrounding objects and also to cases with other surrounding objects, including several different surrounding objects.

In 2 is the lateral distance a between the motor vehicle 2 and the further motor vehicle 10 at a point in time that is determined by the traffic situation shown, represented by a double arrow, the lateral distance a by the distance between the two motor vehicles 2, 10 in a transverse direction 12th transversely to the longitudinal direction 14th of the motor vehicle 2 seen is given. The longitudinal direction extends here 14th in one direction from the stern 16 towards the front 18th of the motor vehicle 2 .

The control and evaluation unit 8th now monitors this lateral distance in the at least one operating mode a to the further motor vehicle 10 . In addition, there is the control and evaluation unit 8th set up the steering system 4th to implement an assistance function according to the invention in such a way that when a first limit value is undershot a1 for the lateral distance a a counter-steering torque is generated and that the counter-steering torque as the value falls below the first limit value a1 is increasingly increased. That assistance function is preferably carried out by an operator or user of the motor vehicle 2 can be activated and deactivated, for example via a switch or button.

Various design variants are also provided for the assistance function, and here two types of design variants are fundamentally to be distinguished from one another.

In the first type, the assistance function supports a vehicle driver, operator or user of the motor vehicle 2 in driving the vehicle without taking away control of the vehicle. In this type of embodiment variant, the counter-steering torque is then preferably limited to a maximum value, which is typically when a second, smaller limit value is reached a2 for the lateral distance a is achieved. This maximum value is selected in such a way that the vehicle driver is able to apply a steering torque that is greater than the maximum value of the counter-steering torque at any time due to the skills to be expected from him. The steering torque is usually specified by the vehicle driver via the steering wheel and the counter-steering torque then typically counteracts this steering torque on the steering wheel as well.

The counter-steering torque thus represents an obstacle that can be overcome and is perceived by the vehicle driver as an additional steering resistance in addition to a basic steering resistance, which, however, can be overcome by the vehicle driver without any problems. This perceived additional steering resistance informs the vehicle driver that the motor vehicle is 2 at least up to the first limit value a1 for the lateral distance a the other motor vehicle 10 has approached. By increasing the counter-steering torque as the value falls below the first limit value a1 the vehicle driver is also informed about the additional steering resistance about how close the motor vehicle is 2 already the other motor vehicle 10 is, so that differentiated information is passed on to the driver of the vehicle via the counter-steering torque. The vehicle driver can then use the steering wheel and the steering resistance to feel how far the motor vehicle is 2 still from the other motor vehicle 10 away is how big the lateral distance is a to another motor vehicle 10 is.

In the second type, a partially autonomous or fully autonomous vehicle guidance is implemented with the aid of the assistance function, in which control of the vehicle guidance is at least partially relinquished by the vehicle driver when he activates the assistance function. In this type of embodiment variant, the counter-steering torque is preferably adapted in such a way that at least a second, smaller limit value is undershot a2 for the lateral distance a is prevented. At the latest when the second lower limit value is reached a2 the value of the counter-steering torque is then typically so high that the corresponding counter-steering torque can no longer be overcome by the vehicle driver and the counter-steering torque represents an insurmountable obstacle.

The value of the counter-steering torque is typically not only dependent on the lateral distance a specified but also as a function of the steering torque specified by the vehicle driver. When the motor vehicle 2 So, for example, drives straight ahead and the vehicle driver performs a steering action through which the motor vehicle 2 threatens to fall below the specified safety margin, i.e. in particular the second, smaller limit value a2 for the lateral distance a , so the steering action is carried out by the assistance function prevented or compensated so that the motor vehicle 2 drives straight again.

The principle can also be applied to cornering. This is then typically done by the control and evaluation unit 8th a counter-steering torque is given, through which the lateral distance a constant at the value of the second, smaller limit value a2 is held as soon as the second, smaller limit value a2 is achieved, in particular regardless of whether the vehicle driver applies a steering torque against the counter-steering torque or not. In other words, in this case the counter-steering torque is preferably adapted to a steering torque generated by the vehicle driver in order to quasi overrule the vehicle driver, regardless of how large the steering torque opposite the counter-steering torque is that the vehicle driver applies.

In such an embodiment variant of the assistance function, the intervention of the control and evaluation unit is also preferred 8th in the steering system 4th only falling below the second, smaller limit value a2 for the lateral distance a prevented, whereas it is still possible for the driver to drive the motor vehicle 2 to steer specifically in the opposite direction to the lateral distance a to another motor vehicle 10 to increase again. I. E. So that in this case a steering action by a vehicle driver through the intervention of the control and evaluation unit 8th in the steering system 4th is quasi canceled when the vehicle driver tries in the direction of the further motor vehicle 10 to steer, whereas a steering action by the vehicle driver is permitted when the vehicle driver is driving the motor vehicle 2 away from further motor vehicle 10 directs.

Furthermore, an embodiment variant in which a mixture of both types is implemented is advantageous. The assistance function then acts preferably between the first limit value a1 and the second, smaller limit value a2 according to the type of the first type and when the second, smaller limit value is reached a2 of the second type. In other words, if the value falls below the first limit value, the vehicle driver a1 initially only receives feedback or information in the form of an additional steering resistance and that only when the second, smaller limit value is reached a2 a further reduction in the lateral distance a is prevented by the assistance function.

To specify a basic steering resistance, a basic counter-steering torque is also preferably specified, on which the counter-steering torque is then possibly superimposed. The basic steering resistance is a steering resistance common in current steering systems and typically only dependent on the rotational position of the steering wheel, which is intended to give the vehicle driver haptic feedback about cornering and the contact between tires and road and in this way convey a certain driving experience.

The previously described design variants of the assistance function relate in particular to steering systems 4th with a steering motor, with such steering systems 4th a corresponding counter-steering torque and possibly also a basic counter-steering torque is applied or generated with the aid of the steering motor. However, the inventive principle also applies to steering systems 4th can be implemented with superimposed steering or with decoupled steering, for example with so-called "drive-by-wire" systems. In these cases, a counter-steering torque is not generated and varied; instead, the steering ratio is adapted, that is, the relationship between the rotational position of the steering system 4th connected and through the steering system 4th rotatable wheels of the motor vehicle 2 and the turning position of the steering wheel.

Depending on the embodiment variant, the steering ratio is adjusted if necessary to such an extent that the steering ratio is also reversed in extreme cases, so that then, for example, the vehicle driver steers to the right and the motor vehicle 2 nevertheless drives to the left, for example to maintain a constant lateral distance from the other motor vehicle in a left turn 10 to keep.

The previously described modes of operation of the variants of the assistance function function in principle regardless of whether the motor vehicle is 2 proceeding from the earth system to the further motor vehicle 10 approaches laterally or whether the other motor vehicle 10 the motor vehicle 2 approaches laterally.

This also means that in the case of the implementation of the second type of embodiment variant of the assistance function or in the case of the mixed variant described above, a type of evasive function is typically also implemented, which is the motor vehicle 2 can automatically evade when the other motor vehicle 10 approaches too far. Because if the control and evaluation unit 8th by controlling the steering system 4th prevents the second, smaller limit a2 for the lateral distance a is fallen below and the further motor vehicle 10 on the motor vehicle 2 moved closed, an evasive movement of the motor vehicle follows 2 in the lateral direction away from the further motor vehicle 10 .

For such cases in particular, it is then further preferred that the sensor system 6th also lane markings 20th can be recognized and lateral distances to the lane markings 20th be monitored. If then, for example, the lateral distance to a lane marking falls below 20th on the other motor vehicle 10 opposite side of the motor vehicle 2 a predetermined lower limit, so will the motor vehicle 2 preferably automatically by the control and evaluation unit 8th either decelerated or accelerated.

If, on the other hand, the first type of embodiment variant of the assistance function is implemented, then it is the control and evaluation unit 8th preferably set up the steering system 4th regardless of possibly existing road markings 20th and in particular independent of a lateral distance from a road marking 20th to control, at least regardless of a lateral distance to a lane marking 20th on the same side as the other motor vehicle 10 .

According to a further advantageous embodiment variant, the motor vehicle 2 also a receiving device 22nd to receive auxiliary data, which from the other motor vehicle 10 be sent. Then there is also the control and evaluation unit 8th set up to evaluate the auxiliary data in such a way that the further motor vehicle 10 is recognized and the lateral distance a is monitored. These auxiliary data are used, for example, to read the sensor data of the sensor system 6th of the motor vehicle 2 to supplement and / or by means of the sensor data of the sensor system 6th determined lateral distances a to verify.

The motor vehicle also preferably has 2 also a transmitting device 24 which is set up to send auxiliary data, the auxiliary data information on the further motor vehicle 10 and to the lateral distance a to the further motor vehicle 10 exhibit. The sensor data typically form the sensor system 6th the basis for the auxiliary data. In the further motor vehicle 10 these auxiliary data can then be used in an analogous manner, at least when the further motor vehicle 10 has a comparable equipment, with which in turn an assistance function of one of the types described above is implemented.

List of reference symbols

2

Motor vehicle

4th

Steering system

6th

Sensor system

8th

Control and evaluation unit

10

another motor vehicle

12th

Transverse direction

14th

Longitudinal direction

16

Rear

18th

front

20th

Lane marking

22nd

Receiving device

24

Sending facility

a

lateral distance

a1

first limit

a2

second limit

Claims (10)

Motor vehicle (2) having a steering system (4), a sensor system (6) for monitoring the surroundings and a control and evaluation unit (8), the control and evaluation unit (8) being set up to evaluate sensor data from the sensor system (6) in this way that a surrounding object (10) is recognized in the surrounding area and a lateral distance (a) to the surrounding object (10) is monitored, characterized in that the control and evaluation unit (8) is set up to control the steering system (4) in such a way that that when the lateral distance (a) falls below a first limit value (a1), a steering ratio is specified, and that the steering ratio is increasingly reduced as the value falls below the first limit value (a1). Motor vehicle (2) according to Claim 1 , characterized in that when the lateral distance (a) falls below the first limit value (a1), a counter-steering torque is generated and that the counter-steering torque is increasingly increased as the value falls below the first limit value (a1). Motor vehicle (2) according to Claim 1 or 2 , characterized in that the control and evaluation unit (8) is set up to control the steering system (4) in such a way that the counter-steering torque is continuously increased as the value falls below the first limit value (a1) or that the steering ratio increases as the value falls below the first limit value (a1) Limit value (a1) is continuously and increasingly reduced. Motor vehicle (2) according to Claim 1 or 2 , characterized in that the tax and evaluation unit (8) is set up to control the steering system (4) in such a way that the counter-steering torque is increased increasingly in several stages as the value falls below the first limit value (a1) or that the steering ratio is increased in several stages as the value falls below the first limit value (a1) Levels is increasingly reduced. Motor vehicle (2) according to one of the Claims 1 until 4th , characterized in that the control and evaluation unit (8) is set up to control the steering system (4) in such a way that, as soon as a second, smaller limit value (a2) for the lateral distance (a) is undershot, the counter-steering torque is kept constant with increasing undershoot is or that if the second, smaller limit value (a2) is undershot for the lateral distance (a), the steering ratio is kept constant with increasing undershoot. Motor vehicle (2) according to one of the Claims 1 until 4th , characterized in that the control and evaluation unit (8) is set up to control the steering system (4) in such a way that falling below a second, smaller limit value (a2) for the lateral distance (a) is prevented. Motor vehicle (2) according to one of the Claims 1 until 6th , characterized in that the control and evaluation unit (8) is set up to control the steering system (4) in such a way that the counter-steering torque is superimposed on a base counter-steering torque dependent on a rotational position of a steering wheel or that the steering ratio is one of a rotational position of a steering wheel dependent base steering ratio is superimposed. Motor vehicle (2) according to one of the Claims 1 until 4th , characterized in that it has a receiving device (22) for receiving auxiliary data which are sent by the surrounding object (10), and that the control and evaluation unit (8) is set up to evaluate the auxiliary data in such a way that the surrounding object (10) is recognized and a lateral distance (a) to the surrounding object (10) is monitored. Motor vehicle (2) according to one of the Claims 1 until 4th , characterized in that it has a transmitting device (24) which is set up to transmit auxiliary data, the auxiliary data having information on the recognized environmental object (10) and on the lateral distance (a) to the environmental object (10). Method for operating a motor vehicle (2) according to one of the preceding claims, comprising a steering system (4), a sensor system (6) for monitoring the surroundings and a control and evaluation unit (8), whereby the control and evaluation unit (8) provides sensor data of the sensor system (6) are evaluated in such a way that a surrounding object (10) is detected in the surrounding area and a lateral distance (a) to the surrounding object (10) is monitored, characterized in that the control and evaluation unit (8) controls the steering system ( 4) controls in such a way that if the lateral distance (a) falls below a first limit value (a1), a steering ratio is specified and the steering ratio is increasingly reduced as the value falls below the first limit value.

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