Method for dynamically adjusting wheel steering angle of at least one vehicle wheel of vehicle by changing tread of vehicle wheels

Abstract

The invention relates to a method for dynamically adjusting a wheel steering angle of at least one vehicle wheel (10, 12) of a vehicle (14), the vehicle (14) comprising a steering system (16) having at least one wheel steering angle controller (18, 20) for changing the wheel steering angle of the vehicle wheel (10, 12), and a vehicle sensor system (22) for driving situation detection, and wherein, in order to adjust the wheel steering angle, the tread of the vehicle wheels (10, 12) is dynamically adapted to the current driving situation. According to the invention, a driving-situation-dependent adjustment value is ascertained as a function of a target value of the track of the vehicle wheels and a mechanical track change of the vehicle wheels that is associated with the current driving situation, and the wheel steering angle adjuster (18, 20) is actuated in order to dynamically adjust the track of the vehicle wheels (10, 12) using the adjustment value, in this way, the tread of the vehicle wheels (10, 12) is adjusted to the target value.

Description

Technical Field

[0001] The invention relates to a method for dynamically adjusting a wheel steering angle of at least one vehicle wheel of a vehicle according to the preamble of claim 1. The invention also relates to a computing unit for carrying out such a method and to a vehicle having such a computing unit. Background Art

[0002] For vehicles and in particular their chassis, manufacturer- or vehicle-specific specifications must in principle be taken into account with regard to kinematic and elasto-kinematic properties, wherein, in addition to the basic design, general comfort and safety aspects also play a role. In this context, wheel-individualized mechanical toe changes have been developed for many scenarios, for example for braking, cornering, passing one-sided obstacles and / or with regard to vehicle load. A correspondingly designed steering system offers the possibility of meeting these wheel toe change specifications independently of the mechanical design of the vehicle or chassis.

[0003] Furthermore, DE 10 2017 221 379 A1 discloses a method for operating a vehicle, wherein the vehicle comprises a steering system having at least one wheel steering angle regulator for changing the wheel steering angle of the vehicle wheels and wherein the toe of the vehicle wheels is dynamically adapted to the current driving situation.

[0004] The object of the present invention is in particular to provide a method for dynamically adjusting the wheel steering angle of at least one vehicle wheel of a vehicle, which has improved properties with regard to adaptability and / or variability. This object is achieved by the features of claims 1, 8 and 9, while advantageous embodiments and developments of the invention can be found in the dependent claims. Summary of the invention

[0005] The invention relates to a method, in particular a computer-implemented method, for dynamically adjusting a wheel steering angle of at least one vehicle wheel of a vehicle, in particular by changing the track width (advantageously toe-in) of the vehicle wheels, wherein the vehicle comprises a steering system and a vehicle sensor system for driving situation recognition, the steering system having at least one wheel steering angle regulator for changing the wheel steering angle of the vehicle wheels, and wherein, in order to adjust the wheel steering angle, the track width of the vehicle wheels is dynamically adapted to the current driving situation.

[0006] It is proposed that, according to a target value of the wheelbase of the vehicle wheels and a mechanical wheelbase change of the vehicle wheels associated with the current driving situation, an adjustment value related to the driving situation is determined, and in order to dynamically adjust the wheelbase of the vehicle wheels while using the adjustment value, a wheel steering angle regulator is controlled so that the wheelbase of the vehicle wheels is set to the target value. The target value of the wheelbase of the vehicle wheels and / or the mechanical wheelbase change of the vehicle wheels associated with the current driving situation can preferably be determined in advance, for example, calculated, measured or called from the operating memory of the vehicle. In particular, the mechanical wheelbase change can be caused by a change in the vehicle height caused by a change in the elastic damping travel at the vehicle wheels and / or by an external force acting on the vehicle wheels and / or the wheel steering angle regulator. At present, the wheel steering angle regulator is therefore controlled to dynamically adjust the wheelbase of the vehicle wheels in a targeted manner, so that the wheelbase of the vehicle wheels is adjusted or corrected to the target value while taking into account the mechanical wheelbase change. For this purpose, a control value, i.e. an additional value, is determined in advance for controlling the wheel steering angle regulator, which control value, in combination with the mechanical track change for the corresponding driving situation, leads to a target value for the track of the vehicle wheels. In the present case, the mechanical track change is therefore adjusted or corrected to the correct target value by a software function if there is a deviation between the target value and the mechanical track change for the corresponding driving situation. With this design, in particular, adaptability and / or variability can be improved, and track change specifications and / or track change requirements can be met independently of the mechanical design of the vehicle or chassis. In addition, an advantageous adjustment of the track of the vehicle wheels can be achieved in every driving situation.

[0007] The vehicle is preferably configured as a motor vehicle and comprises in particular a steering system and a vehicle sensor system, which is configured to provide at least one sensor variable associated with the current driving situation. For this purpose, the vehicle sensor system may comprise at least one sensor element, in particular an electrical, magnetic and / or optical sensor element. Alternatively or additionally, the vehicle sensor system may determine the sensor variable associated with the current driving situation by means of a sensor model, by means of a control variable and / or by means of information from at least one other actuator. Furthermore, the steering system is preferably configured as a steer-by-wire system, in which the steering specification (in particular of the driver) is advantageously transmitted to the vehicle wheels in a purely electrical manner. In this case, the steering system comprises at least one wheel steering angle regulator and advantageously comprises an operating unit mechanically separated from the wheel steering angle regulator. In this context, an "operating unit" is to be understood in particular as an input unit that can be operated by the driver for operating the at least one wheel steering angle regulator. The operating unit may in particular comprise a steering handle (for example in the form of a steering wheel) and advantageously comprises a feedback actuator (for example in the form of an electric motor) for generating a steering resistance and / or a restoring torque on the steering handle. A “wheel steering angle adjuster” is to be understood in particular as an actuator unit which is operatively connected to at least one vehicle wheel and which is provided for transmitting a steering specification to the vehicle wheel by changing the wheel steering angle of at least one vehicle wheel and thereby advantageously controlling at least one orientation of the vehicle wheel and / or influencing the direction of travel of the vehicle. For this purpose, the wheel steering angle adjuster advantageously comprises at least one steering adjustment element (e.g. in the form of a rack) and at least one steering actuator (e.g. in the form of an electric motor) operatively connected to the steering adjustment element. In this case, the wheel steering angle adjuster can be assigned in particular to a front axle or a rear axle of the vehicle. Furthermore, the vehicle can comprise further components and / or assemblies, for example at least one spring-damper unit, which is particularly assigned to a vehicle wheel, for absorbing and damping forces acting on the vehicle wheel from the ground.

[0008] In addition, the vehicle comprises at least one computing unit, which is configured to execute a method for dynamically adjusting the wheel steering angle of the at least one vehicle wheel. A "computing unit" is to be understood in particular as an electrical and / or electronic unit having an information input, an information processing unit and an information output. Advantageously, the computing unit also has at least one processor, at least one operating memory, at least one input and / or output device, at least one operating program, at least one control routine, at least one computing routine, at least one determination routine, at least one evaluation routine and / or at least one adjustment routine. In particular, the computing unit is configured to determine an adjustment value related to the driving situation based on a target value for the wheel width of the vehicle wheels and a mechanical wheel width change associated with the current driving situation. In addition, the computing unit can be configured to determine the target value and the mechanical wheel width change of the vehicle wheels. In addition, the computing unit can be configured to control a wheel steering angle regulator. In this context, the computing unit is particularly configured to control the wheel steering angle regulator in such a way that the wheel width of the vehicle wheels is adjusted to the target value in order to dynamically adjust the wheel width of the vehicle wheels using the adjustment value. Preferably, the computing unit is integrated into a control unit of the vehicle, for example a central vehicle control unit, or into a control unit of the steering system, in particular in the form of a steering control unit. "Provided" is to be understood in particular as being specially programmed, designed and / or equipped. "An object is provided for a certain function" is to be understood in particular as meaning that the object fulfills and / or performs the certain function in at least one application state and / or operating state.

[0009] Preferably, the target value is also determined as a function of a steering predefined, advantageously a steering predefined at a steering handle of the steering system, and as a function of at least one sensor variable of the vehicle sensor system, advantageously a plurality of sensor variables of the vehicle sensor system. Furthermore, the mechanical track change is preferably determined as a function of a steering predefined, advantageously a steering predefined at a steering handle of the steering system, and as a function of at least one sensor variable of the vehicle sensor system, advantageously a plurality of sensor variables of the vehicle sensor system. In this case, the target value is preferably purely controlled and does not need to be adapted to the corresponding driving situation mechanically or electronically or software-based, while the mechanical track change is determined specifically for the corresponding current driving situation. As a result, the target value and / or the mechanical track change can be advantageously determined simply.

[0010] Furthermore, it is proposed to use a sensor model for determining the target value and / or the mechanical track change. The sensor model may include a plurality of sensor elements or a combination of sensors and / or may include, for example, corresponding models of vehicle axles. This advantageously allows the target value and / or the mechanical track change to be determined precisely.

[0011] If the vehicle sensor system for determining the mechanical track change comprises at least one driving dynamics sensor, at least one spring travel sensor, in particular assigned to a spring-damper unit of the vehicle, and / or at least one force sensor, in particular assigned to a wheel steering angle regulator, advantageous driving situation recognition and particularly simple determination of the mechanical track change can be achieved. The driving dynamics sensor can be provided, for example, to detect a lateral acceleration, a yaw rate, a vehicle speed, a roll angle and / or a longitudinal acceleration of the vehicle.

[0012] Furthermore, the steering system can be designed as a steer-by-wire system and the wheel steering angle regulator can be designed as a central regulator. In this case, the wheel steering angle regulator is associated with at least two, in particular steerable, vehicle wheels. However, it is preferably provided that the steering system is designed as a steer-by-wire system and the wheel steering angle regulator is designed as a single-wheel regulator. In this case, the steering system can advantageously include a plurality of wheel steering angle regulators, wherein each wheel steering angle regulator is associated with exactly one, in particular steerable, vehicle wheel. This makes it possible to achieve an advantageous wheel-individualized track setting, wherein individual events, such as a one-sided overpass, can also be detected and taken into account when dynamically adjusting the track of the vehicle wheels.

[0013] In another embodiment, it is proposed that the steering system comprises at least one further wheel steering angle controller designed as a single wheel controller for changing the wheel steering angle of at least one further vehicle wheel, wherein for each of the vehicle wheels, a separate, wheel-specific adjustment value is determined and set by means of the corresponding wheel steering angle controller. Thus, in the present case, a further adjustment value related to the driving situation is determined as a function of a further target value for the wheel width of the further vehicle wheels and a further mechanical wheel width change of the further vehicle wheels associated with the current driving situation, so that a separate, wheel-specific adjustment value is determined for each of the vehicle wheels, wherein, in order to dynamically adjust the wheel width of the further vehicle wheels using the further adjustment value, the further wheel steering angle controller is actuated in such a way that the wheel width of the further vehicle wheels is set to the further target value. Furthermore, the further target value for the wheel width of the further vehicle wheels and / or the further mechanical wheel width change of the further vehicle wheels associated with the current driving situation can be determined in advance, for example calculated, measured or retrieved from an operating memory of the vehicle. Preferably, the wheel steering angle regulator and the further wheel steering angle regulator are also assigned to the same axle of the vehicle, i.e. the front axle or the rear axle. In addition, the further target value and / or the further mechanical track change are determined as a function of a steering specification, advantageously a steering specification at the steering handle of the steering system and as a function of at least one further sensor variable of the vehicle sensor system, advantageously a plurality of further sensor variables of the vehicle sensor system. In principle, the target value and the further target value and / or the sensor variable and the further sensor variable can also be identical to one another. This allows a further improvement of the wheel-individualized track setting to be achieved.

[0014] The method and vehicle for dynamically adjusting the wheel steering angle of at least one vehicle wheel are not limited to the above-described applications and embodiments. In particular, the method and vehicle for dynamically adjusting the wheel steering angle of at least one vehicle wheel can have a number of individual elements, components and units different from the number mentioned in this article to achieve the functional method described in this article. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Further advantages emerge from the following description of the drawings. An exemplary embodiment of the invention is shown in the drawings.

[0016] Figure 1a - b shows in a simplified illustration a vehicle having a steering system which is designed, by way of example, as a steer-by-wire system; and

[0017] Figure 2 An exemplary flow chart showing essential method steps of a method for dynamically adjusting a wheel steering angle of at least one vehicle wheel of a vehicle is shown. DETAILED DESCRIPTION

[0018] Figure 1a and 1b A vehicle 14, designed as a passenger car by way of example, is shown in a simplified illustration, which has a plurality of vehicle wheels 10, 12 and a steering system 16. The steering system 16 has an operative connection to the vehicle wheels 10, 12 and is provided for influencing the direction of travel of the vehicle 14. In addition, the steering system 16 is designed in the present case as a steer-by-wire system, in which a steering specification is transmitted electrically to the vehicle wheels 10, 12 in at least one operating state.

[0019] The steering system 16 has an operating unit 38 known per se. The operating unit 38 comprises a steering handle 40, which can be operated in particular by the driver (for example in the form of a steering wheel), and a feedback actuator 42, which is in particular mechanically coupled to the steering handle 40. In the present case, the feedback actuator 42 is provided at least for generating a steering resistance and / or a restoring torque on the steering handle 40. Alternatively, the steering handle can also be designed as a joystick, a steering rod and / or a steering ball or the like. In addition, the feedback actuator can also be omitted in principle. In addition, it is also conceivable to completely omit the operating unit.

[0020] In addition, the steering system 16 has at least one wheel steering angle regulator 18, 20. In the present case, the steering system 16 includes two wheel steering angle regulators 18, 20 configured as single-wheel regulators, and therefore in particular wheel-individualized steering devices. The wheel steering angle regulators 18, 20 are at least substantially identical in structure, and can be configured as translational and / or rotational regulators in particular. The wheel steering angle regulators 18, 20 are configured separately from each other and do not have a mechanical connection in the present case. The wheel steering angle regulators 18, 20 can be controlled independently of each other. In addition, the wheel steering angle regulators 18, 20 are purely electrically connected to the operating unit 38 and therefore to the steering handle 40. Each of the wheel steering angle regulators 18, 20 has an operative connection with exactly one of the vehicle wheels 10, 12, in the present case, the front wheel. The wheel steering angle regulators 18, 20 are provided for changing the respective wheel steering angles of the corresponding vehicle wheels 10, 12 according to the steering pre-regulation. For this purpose, each of the wheel steering angle regulators 18 and 20 includes a steering adjustment element 44, 46 and a steering actuator 48, 50, which is configured as a rack, and the steering actuator works together with the steering adjustment elements 44 and 46 and is configured as an electric motor. In principle, the steering system can also include a wheel steering angle regulator configured as a central regulator. In addition, the steering system can also include at least four wheel steering angle regulators configured as single-wheel regulators. In principle, the steering system can also include a combination of a wheel steering angle regulator configured as a single-wheel regulator and a wheel steering angle regulator configured as a central regulator. In addition, in particular, at least one wheel steering angle regulator can also be assigned to a vehicle wheel configured as a rear wheel. In addition, the wheel steering angle regulator can also be different from the single-wheel regulator and / or the central regulator, and can be installed in addition to the existing single-wheel regulator and / or the central regulator. In this case, the wheel steering angle regulator can therefore be configured as a special additional regulator.

[0021] Furthermore, the vehicle 14 comprises at least one spring-damper unit 32, 34. In the present case, the vehicle 14 comprises a plurality of spring-damper units 32, 34 configured as chassis dampers, wherein two of the spring-damper units 32, 34 are arranged in a Figure 1a 1 and 2. The spring-damper units 32, 34 are shown by way of example and are provided with reference numerals. The spring-damper units 32, 34 are at least substantially identical in structure. Here, each of the spring-damper units 32, 34 is arranged in the region of one of the wheel steering angle adjusters 18, 20 and is in particular assigned to the corresponding vehicle wheel 10, 12. In principle, the vehicle can also have a different number of spring-damper units.

[0022] Furthermore, the vehicle 14 comprises a vehicle sensor system 22 known per se for driving situation recognition. The vehicle sensor system 22 is provided for providing at least one sensor variable associated with the current driving situation. For this purpose, the vehicle sensor system 22 can include at least one sensor element, in particular an electrical, magnetic and / or optical sensor element. In the present case, the vehicle sensor system 22 comprises, for example, at least one driving dynamics sensor 24, a plurality of spring travel sensors 26, 27 and a plurality of force sensors 28, 30, wherein each of the spring damper units 32, 34 is assigned to one of the spring travel sensors 26, 27, wherein each of the wheel steering angle regulators 18, 20 is assigned to one of the force sensors 28, 30. The driving dynamics sensor 24 can be provided for detecting, for example, a lateral acceleration, a yaw rate, a vehicle speed, a roll angle and / or a longitudinal acceleration of the vehicle 14. The spring travel sensors 26, 27 can be provided for detecting a change in vehicle height, in particular by a change in the elastic damping travel at the respective vehicle wheels 10, 12. Furthermore, force sensors 28, 30 may be provided for detecting external forces acting on vehicle wheels 10, 12 and / or wheel steering angle regulators 18, 20, for example in the form of steering tie rod forces. Furthermore, vehicle sensor system 22 may also determine sensor variables associated with the current driving situation with the aid of a sensor model, as an alternative or in addition. However, in principle, it is also conceivable to completely omit driving dynamics sensors, spring travel sensors and / or force sensors. Furthermore, sensor variables associated with the current driving situation may also be determined with the aid of control variables and / or with the aid of information from at least one other actuator.

[0023] The vehicle 14 furthermore has a control unit 52. In the present case, the control unit 52 is designed as a steering control unit and is therefore part of the steering system 16. The control unit 52 has an electrical connection to the operating unit 38. The control unit 52 also has an electrical connection to the wheel steering angle regulators 18, 20. Furthermore, the control unit 52 has an electrical connection to the vehicle sensor system 22. The control unit 52 is provided at least for controlling the operation of the steering system 16.

[0024] The control unit 52 has a computing unit 36. The computing unit 36 ​​includes at least one processor (not shown), for example in the form of a microprocessor, and at least one operating memory (not shown). In addition, the computing unit 36 ​​includes at least one operating program stored in the operating memory, which has at least one calculation routine, at least one determination routine, at least one evaluation routine and / or at least one adjustment routine. In principle, the controller can also be different from the steering controller and be designed, for example, as a single central vehicle controller with a central computing unit. In addition, it is also conceivable to provide a separate controller for each wheel steering angle regulator and for the operating unit and to connect them to each other in a communicative manner.

[0025] Furthermore, the vehicle 14 and / or the steering system 16 may include further components and / or assemblies (not shown), such as an internal vehicle sensor system for detecting operating signals of at least one of the wheel steering angle regulators 18 , 20 , an onboard computer known per se and / or a navigation device known per se.

[0026] In general, for vehicles and in particular for their chassis, manufacturer- or vehicle-specific specifications must be taken into account with regard to kinematic and elasto-kinematic properties, wherein, in addition to the basic design, general comfort and safety aspects also play a role. A correspondingly designed steering system, which preferably has individually steered vehicle wheels, offers the possibility of meeting these track variation specifications independently of the mechanical design of the vehicle or chassis.

[0027] In order to increase adaptability and / or variability, a method is therefore proposed below for dynamically adjusting the wheel steering angle of at least one vehicle wheel 10, 12 of a vehicle 14, specifically in particular by changing the track width of the vehicle wheels 10, 12. In the present case, the method is described here by way of example with respect to a vehicle wheel 10 and a wheel steering angle controller 18 assigned to the vehicle wheel 10, wherein, however, the following description can also be applied to other vehicle wheels 12 and other wheel steering angle controllers 20 assigned to the other vehicle wheels 12. In the present case, in particular, a computing unit 36 ​​is provided for carrying out the method and, for this purpose, has in particular a computer program with corresponding program code.

[0028] According to the invention, a driving situation-dependent adjustment value (especially in the form of an additional value) is determined based on a target value for the wheelbase of the vehicle wheels 10 and a mechanical wheelbase change associated with the current driving situation. The target value and the mechanical wheelbase change can be determined in advance, for example, calculated, measured or retrieved from the operating memory of the computing unit 36 ​​or another operating memory of the vehicle 14. However, in principle, it is also conceivable to omit the separate determination of the target value and / or the mechanical wheelbase change. In addition, the mechanical wheelbase change can be caused, for example, by a change in the vehicle height caused by a change in the elastic damping travel at the vehicle wheel 10 and / or by external forces acting on the vehicle wheel 10 and / or the wheel steering angle regulator 18. The adjustment value is then used to control the wheel steering angle regulator 18, wherein the wheel steering angle regulator 18 is controlled in such a way that the wheelbase of the vehicle wheel 10 is set to the target value in order to dynamically adjust the wheelbase of the vehicle wheel 10 using the adjustment value. In the present case, the method is also used to adjust the toe of the vehicle wheel 10. In principle, the method can also be used to adjust the camber of the vehicle wheel 10.

[0029] In the present case, the mechanical track change is therefore adjusted or corrected to the correct target value by means of a software function if there is a deviation between the target value and the mechanical track change for the respective driving situation. The goal is to thereby set a specific driving situation-dependent and wheel-individualized additional value based on a given mechanical axle design. In this way, track change specifications and / or track change requirements can be met, in particular independently of the mechanical design of the vehicle 14 or the chassis.

[0030] In the present case, the target value can also be determined based on a steering predefined and preferably based on a plurality of sensor variables of the vehicle sensor system 22. In this case, the steering predefined can be applied by the driver to the steering handle 40, for example, so that the driver can predetermine the general steering predefined. In a further step, the required Ackermann conditions can be set. In this case, the target values ​​of the vehicle wheels 10 or the vehicle wheels 10, 12 generated in this way are purely controlled and do not need to be adapted to the corresponding driving situation mechanically or electronically or software-based. In principle, in this context, a sensor model can also be used for determining the target value.

[0031] The mechanical track change can be determined based on a plurality of sensor variables of the vehicle sensor system 22 and preferably based on steering specifications and is specific to the respective current driving situation. In the present case, in particular sensor variables of the driving dynamics sensor 24, at least one of the spring travel sensors 26, 27 and / or at least one of the force sensors 28, 30 can be used. This allows, for example, a further optimization of the adjustment value by means of a mapping of mechanical properties, in particular due to elastic damping, and / or based on the vehicle dynamics of the vehicle 14. In principle, a sensor model can also be used in the present case for determining the mechanical track change.

[0032] Furthermore, depending on the driving situation, it may be expedient to determine a separate, wheel-specific adjustment value for each of the vehicle wheels 10, 12 and set it by means of the respective wheel steering angle controller 18, 20. This makes it possible to advantageously detect individual events, such as unilateral driving over an obstacle, and take this into account when dynamically adjusting the respective wheel track.

[0033] Therefore, the method can in principle be set up for dynamically adjusting the wheel steering angle of a single vehicle wheel 10, 12 of the vehicle 14, specifically, in particular by changing the wheel width of the vehicle wheels 10, 12, and / or be set up for dynamically adjusting the wheel steering angle of multiple vehicle wheels 10, 12 of the vehicle 14, specifically, in particular by changing the corresponding wheel width of the vehicle wheels 10, 12.

[0034] The first application case of the method described above occurs, for example, in the case of a spring-damped vehicle 14. By way of example, in this case, the track change should be 1° to the left and right at a spring-damped 5 mm. However, due to chassis reasons, only a mechanical track change of 0.5° occurs each time, so that in this case, the wheel steering angle controllers 18, 20 are controlled in such a way that 0.5° is added each time in order to dynamically adjust the respective track of the vehicle wheels 10, 12 using the respective adjustment values.

[0035] A second application case of the method described above can occur, for example, when the vehicle 14 is braked. By way of example, in this case, the track change should be 1.75° to the left and right when braking at 0.8 g. However, due to chassis reasons, only a mechanical track change of 1° occurs each time, so that in this case, the wheel steering angle controllers 18, 20 are controlled in such a way that 0.75° is added each time in order to dynamically adjust the respective track of the vehicle wheels 10, 12 using the respective adjustment values.

[0036] at last, Figure 2 An exemplary flow chart showing essential method steps of a method for dynamically adjusting a wheel steering angle of at least one vehicle wheel of a vehicle 14 is shown.

[0037] In method step 60, the current driving situation and the need for dynamically adjusting the wheel steering angle of at least one vehicle wheel 10, 12 of vehicle 14, specifically in particular by changing the track width of vehicle wheels 10, 12, are first ascertained. For this purpose, computing unit 36 ​​may be configured, for example, to ascertain and evaluate at least one sensor variable of vehicle sensor system 22.

[0038] In a subsequent method step 62 , a target value for the wheelbase of the at least one vehicle wheel 10 , 12 and / or a mechanical wheelbase change of the at least one vehicle wheel 10 , 12 associated with the current driving situation can be ascertained.

[0039] In a subsequent method step 64 , a driving situation-dependent adjustment value, in particular an adjustment value in the form of an additional value, is then ascertained as a function of the target value and the mechanical track change.

[0040] In method step 66, at least one of the wheel steering angle controllers 18, 20 is actuated in order to dynamically adjust the track width of the at least one vehicle wheel 10, 12 using the adjustment value so that the track width of the vehicle wheels 10, 12 is set to a target value and the wheel steering angle of the at least one vehicle wheel 10, 12 is changed. The mechanical track width change can thus be adjusted or corrected to the correct target value by a software function if there is a deviation between the target value and the mechanical track width change for the respective driving situation.

[0041] Figure 2 The exemplary flow chart in the description is intended to describe only by way of example a method for dynamically adjusting a wheel steering angle of at least one vehicle wheel of a vehicle 14. In particular, individual method steps may also be varied or additional method steps may be added. In this context, it is conceivable, for example, to dispense with a separate determination of a target value and / or a separate determination of a mechanical wheel track change and thus to dispense with method step 62. Furthermore, the method can in principle be used for dynamically adjusting a wheel steering angle of a single vehicle wheel 10, 12 of a vehicle 14 and / or for dynamically adjusting a wheel steering angle of a plurality of vehicle wheels 10, 12 of a vehicle 14.

Claims

1. A method for dynamically adjusting a wheel steering angle of at least one vehicle wheel (10, 12) of a vehicle (14), wherein: The vehicle (14) comprises a steering system (16) and a vehicle sensor system (22) for driving situation recognition, the steering system having at least one wheel steering angle regulator (18, 20) for changing the wheel steering angle of the vehicle wheels (10, 12), and wherein, in order to adjust the wheel steering angle, the track width of the vehicle wheels (10, 12) is dynamically adapted to the current driving situation, characterized in that a driving situation-dependent adjustment value is determined based on a target value for the track width of the vehicle wheels and a mechanical track width change of the vehicle wheels associated with the current driving situation, and in order to dynamically adjust the track width of the vehicle wheels (10, 12) using the adjustment value, the wheel steering angle regulator (18, 20) is controlled in such a way that the track width of the vehicle wheels (10, 12) is set to the target value.

2. The method according to claim 1, characterized in that The mechanical track change is caused by a change in vehicle height, in particular by a change in the elastic damping travel at the vehicle wheels (10, 12) and / or by external forces acting on the vehicle wheels (10, 12) and / or the wheel steering angle adjusters (18, 20).

3. The method according to claim 1 or 2, characterized in that: The target value and / or the mechanical track change are ascertained as a function of a steering specification and as a function of at least one sensor variable of the vehicle sensor system (22).

4. The method according to claim 3, characterized in that A sensor model is used to determine the target value and / or the mechanical track change.

5. The method according to any one of the preceding claims, characterized in that The vehicle sensor system (22) comprises at least one driving dynamics sensor (24), at least one spring travel sensor (26, 27) which is particularly associated with a spring damper unit (32, 34) of the vehicle (14) and / or at least one force sensor (28, 30) which is particularly associated with the wheel steering angle regulator (18, 20).

6. The method according to any one of the preceding claims, characterized in that The steering system (16) is designed as a steer-by-wire system and the wheel steering angle regulators (18, 20) are designed as single-wheel regulators.

7. The method according to claim 6, characterized in that The steering system (16) comprises at least one further wheel steering angle regulator (18, 20) designed as a single-wheel regulator for changing the wheel steering angle of at least one further vehicle wheel (10, 12), wherein for each of the vehicle wheels (10, 12), a separate, wheel-individualized adjustment value is determined and set by means of the respective wheel steering angle regulator (18, 20).

8. A computing unit (36) for carrying out the method according to any of the preceding claims.

9. A vehicle (14), in particular a motor vehicle, comprising at least one vehicle wheel (10, 12), a steering system (16), a vehicle sensor system (22) and a computing unit (36) according to claim 8, wherein the steering system comprises at least one wheel steering angle regulator (18, 20) for changing the wheel steering angle of the vehicle wheel (10, 12), and the vehicle sensor system is used for driving situation recognition.

Images