DE102011016052A1 - Method for determining target support moment in power steering system of motor car, involves assigning curve representing connection between hand and support moments, and determining target moment based on hand moment and vehicle velocity - Google Patents

Abstract

The method involves assigning a moment curve, and a vehicle speed or a speed range, where the moment curve represents a connection between a hand moment (MH) and a support moment. A temporary support moment is determined from the moment curve. An adjustable adaptation factor is assigned to a vehicle velocity (v) or a velocity interval. A moment-adapted support is determined as a product of a preliminary assist torque and the adaptation factor is determined. A target support moment is determined in dependence of the hand moment and the vehicle velocity. Independent claims are also included for the following: (1) a device for determining target support moment in a steering system, comprising a control device (2) a steering system.

Description

The invention relates to a method and a device for determining a desired assist torque in a steering system and a steering system.

In modern motor vehicles so-called power steering systems are usually used. In these power steering systems, a support torque is generated by means of a suitable actuator which assists a motor vehicle driver in steering maneuvers. Suitable actuators can be electromechanical actuators, for. As electric machines, or hydraulic actuators.

A support torque is determined inter alia as a function of a manual torque, wherein the manual torque from a motor vehicle driver z. B. means of a steering handle, applied torque. This is z. B. by means of a suitable torque sensor, which z. B. can be arranged in or on a steering column, detectable. A functional relationship between a detected manual torque and a target assist torque to be generated may be in the form of a characteristic z. B. stored in a memory device, wherein a central evaluation and control device generates a desired assist torque by means of an evaluation of the characteristic. In order to take account of a speed-dependent steering behavior, a desired assist torque can likewise be determined as a function of a vehicle speed.

So revealed the US 2005/0140322 A1 a motor vehicle whose properties are variable. Further, the document discloses a control device of a power steering, which allows adjustment of desired steering characteristics by a motor vehicle driver. Further, the document discloses a torque sensor and a speed sensor. Further, the document discloses that steering characteristics set by means of an adjuster are input to a controller. A current that is delivered to an engine is determined as a function of the torque, the vehicle speed and the steering characteristics. Further, the document discloses a single characteristic that represents a relationship between a manual torque and a target assist torque. Furthermore, the publication discloses a correction factor by means of which a desired assisting torque determined by means of the aforementioned characteristic curve can be adapted. The correction factor depends on a vehicle speed. Next, a motor vehicle driver set the characteristic between manual torque and target assist torque. Also, a motor vehicle driver can adjust the course of a correction factor over a vehicle speed.

The DE 10 2006 017 714 A1 discloses a method for characteristic or map-dependent variation of the steering torque to be applied via a steering wheel of an active or semi-active steering system. A control device controls a device for the generation of steering torque as a function of at least two characteristic curves or characteristic maps which are assigned different steering or torques. From a driver, one of the characteristics or one of the maps is manually selectable. Further, the document discloses that higher or lower steering torque is generated for a predetermined period of time after the selection of one of the further controls underlying characteristic over the characteristic to be generated steering moment and only after the expiration of the time period, the associated steering torque is generated.

The DE 10 2008 006 847 A1 discloses a steering system for a vehicle, wherein a steering wheel is connected to steerable vehicle wheels and damping means for damping an electric Lenkaktoreinheit for steering assistance are controllable such that at least two electrical phases of the electric Lenkaktoreinheit are circuitry coupled. Next, a permanent mechanical operative connection and / or hydraulic operative connection is formed between the steering wheel and the steerable vehicle wheels. In this case, a strength of the support of the steering movement can be adjusted speed-dependent.

The technical problem arises of providing a method and apparatus for determining a desired assist torque in a steering system and a steering system that allows for improved adjustment of steering characteristics to a steering behavior desired by a motor vehicle driver, in addition to optimal adjustment of steering characteristics a vehicle speed or a time course of a manual torque is achieved.

The solution of the technical problem results from the objects having the features of claims 1, 7 and 9. Further advantageous embodiments of the invention will become apparent from the dependent claims.

A method is proposed for determining a desired assist torque in a steering system. The steering system may be a power steering system that includes an actuator for generating an assist torque to assist a motor vehicle operator during a steering maneuver. The actuator can in this case an electromechanical or a hydraulic actuator or a be another actuator for generating a support torque. The target assist torque may serve as a reference variable for a subordinate control loop of the actuator. The desired assist torque is determined at least as a function of a manual torque and a vehicle speed. The manual torque refers to a torque generated by a motor vehicle driver by means of a steering handle, such as a steering wheel, and z. B. is applied to a steering column of the steering system. The hand moment can be z. B. be detected by means of a suitable sensor. The vehicle speed can also be detected by means of a suitable sensor.

A first vehicle speed or a first speed interval is associated with a first torque characteristic. The torque characteristic here represents a functional relationship between a magnitude of the manual torque and a magnitude of the assist torque. The first torque characteristic may in this case be stored, for example, in a memory device of the steering system. Corresponds to the current vehicle speed of the first vehicle speed or the current vehicle speed is in the first speed interval, then a support torque can be determined by means of the first torque curve as a function of the current manual torque. The torque characteristic also determines a dynamic behavior of the target assist torque, in particular, how large a change in the target assist torque is in response to a change in the manual torque.

The first torque characteristic thus represents a static and dynamic relationship between the manual torque and the assist torque. A first provisional assist torque is determined as the assist torque resulting from the first torque characteristic.

The first vehicle speed or the first speed interval is associated with a first adjustable adaptation factor, wherein a first adapted assist torque is determined as a product of the first provisional assist torque and the first adaptation factor. The adjustable adaptation factor can be z. B. be set by a motor vehicle driver by means of a suitable input device. In this way, therefore, the assistance torque determined by means of the first torque characteristic can be changed as a function of a motor vehicle driver's intention.

According to the invention, at least one further vehicle speed or at least one further vehicle speed interval is assigned an additional torque characteristic. Preferably, the at least one further torque characteristic is different from the first torque characteristic, in particular it has a different course from the first torque characteristic. As a result, steering characteristics or a steering behavior can be adapted to different vehicle speeds in an advantageous manner.

Another provisional support torque is determined as the support torque resulting from the further torque characteristic, for which purpose the further torque characteristic can be evaluated as a function of a current manual torque. Furthermore, the at least one further vehicle speed or the at least one further speed interval is assigned a further adaptation factor, wherein at least one further adapted assist torque is determined as the product of the at least one further provisional assist torque and the at least one further adaptation factor. The resulting desired assist torque is then determined as a function of the first and the at least one further adapted assist torque.

Here, it is possible to determine only the first adapted target assist torque when an actual vehicle speed is equal to the first vehicle speed or in the first speed interval. Also, only the further adapted assist torque can be determined if the current vehicle speed is equal to the further vehicle speed or lies in the further speed interval. In this case, the resulting target assist torque is equal to the first or further adapted assist torque.

Preferably, in particular if the current vehicle speed lies between the first and the further vehicle speed or between the first and the further speed interval, the first and the further setpoint assistance torque can preferably be determined in parallel, or else sequentially. This can also be done if the current vehicle speed is equal to the first or further vehicle speed. This advantageously results in a simple, computational implementability.

The first and the at least one further vehicle speed are different here. Also, the first, the at least one further speed interval are different and preferably do not overlap. Due to the speed-dependent torque characteristics results in an advantageous manner an improved Adjustment of a support torque as a function of the manual torque or a time course of the manual torque, which is adapted to a speed-related steering behavior or steering characteristics improved. For example, in this case an assist torque at higher vehicle speeds may be lower at the same hand torque than at lower speeds, which advantageously results in improved steering characteristics with regard to operating safety of the motor vehicle. Also, at low vehicle speeds, an increase in manual torque may cause a greater increase in target assist torque than at higher vehicle speeds.

By assigning adaptation factors to the torque characteristics, steering performance or steering characteristics for each of the vehicle speeds or each of the speed intervals may be advantageously adapted to a behavior desired by a motor vehicle driver. For example, it is advantageously possible that a "hard" steering behavior at high vehicle speeds, in which the adaptation factor z. B. is 1, by an adaptation factor that is greater than 1 to soften, so to increase a support torque.

The invention thus advantageously makes it possible to adapt an improved adaptation of a steering behavior to the vehicle speed additionally improved by the torque characteristic curves available for several vehicle speeds to a motor vehicle driver, thereby further increasing operational safety of the motor vehicle.

In a further embodiment, the first torque characteristic is different from the at least one further torque characteristic. If more than two torque characteristics exist, then at least one of the torque characteristics is different from another torque characteristic. In this case, two or more torque characteristics associated with different vehicle speeds or speed intervals may be the same. Mutually different torque characteristics in this case have a variation over a size of the manual torque and / or a different magnitude of the assist torque. For example, the various torque characteristics associated with different vehicle speeds or different speed intervals may all be linear or all exponential, with at least two of these torque characteristics having a different slope or different exponent. Also, different torque characteristics may have different axis sections. Of course, it is also possible that mutually different torque characteristics of different functional gradients, for example, a first torque curve a linear course and a further torque curve have an exponential course.

This results in an advantageous manner that different vehicle speeds or speed intervals, a different steering behavior in the form of a curve and / or a magnitude of a support torque depending on a course and / or size is associated with the manual torque, which in turn by setting the adaptation factor a desired behavior the motor vehicle driver is customizable. This results in a desired steering behavior or desired steering properties from a course of the assist torque and / or a magnitude of the assist torque over a manual torque.

In a further embodiment, the desired assistance torque is determined as a function of the vehicle speed of interpolated values between the first and the at least one further adapted assisting torque. For example, if there is a vehicle speed which is greater than the first vehicle speed but less than the at least one further vehicle speed, then a linear progression of the desired assist torque as a function of the vehicle speed can be assumed, the linear progression being dependent on the first and the at least a further adapted assist torque and the associated vehicle speeds is determined. For this purpose, the first and the at least one further adapted assist torque can be calculated in parallel. If, for example, an actual vehicle speed is detected, then an adapted assisting torque for the next-following vehicle speed, which is assigned to a torque characteristic, and an adapted assisting torque for the next-higher vehicle speed, which is assigned a torque characteristic, can be determined, preferably in parallel, but also sequentially ,

If a torque characteristic is assigned to a speed interval and an actual vehicle speed lies between two speed intervals, then the desired assistance torque can be determined as a value interpolated as a function of the vehicle speed between the first and the at least one further adapted assist torque, wherein a linear relationship as a function of central average values of the Speed intervals is determined. This advantageously results in a determination, as simple as possible, of desired assist torques as a function of vehicle speeds, which is not directly associated with a torque characteristic.

In a further embodiment, the first and the at least one further torque characteristic are set as a function of an adjustable profile, wherein the adjustable profile is selected from at least two profiles. Each profile is thus assigned a set of a first and at least one further torque curve. For example, therefore, a first torque characteristic and a second torque characteristic are assigned to a first profile, which in turn are assigned to different vehicle speeds. A second profile is likewise assigned a first and a second torque characteristic, which in turn are assigned to the first and the further vehicle speeds. In this case, at least one of the torque characteristics associated with a first profile is different from the corresponding torque characteristic assigned to the further profile. The corresponding torque characteristic here denotes the torque characteristic which is assigned to the same vehicle speeds or the same speed intervals in the first and the further profile. Thus, for example, the first torque characteristic of the first profile can be equal to the first torque characteristic of the further profile, but in this case at least one of the further torque characteristics of the first profile is different from a corresponding thereto torque characteristic of the other profile.

The profile is here z. B. adjustable by means of a suitable adjustment by a motor vehicle driver. The profiles can hereby z. B. the profiles include "athletic", "comfortable" and "normal". This makes it possible in an advantageous manner to set a general steering behavior by selecting a profile, which can then be further adjusted by a subsequent adjustment of adaptation factors.

In a further embodiment, an adjustment of the first adaptation factor is limited to a minimum value assigned to the first adaptation factor and a maximum assigned to the first adaptation factor. Alternatively or cumulatively, an adjustment of the at least one further adaptation factor is limited to a minimum assigned to the at least one further adaptation factor and a maximum assigned to the at least one further adaptation factor. This results in an increased reliability of the proposed method, since adaptation factors can not fall below or exceed predetermined ranges. By limiting the adaptation factor to a maximum, for example, an overreaction of the power steering can be prevented because no excessively high support torque is generated. The minimum associated with the first adaptation factor and the maximum associated with the first adaptation factor and / or the minimum assigned to the further adaptation factor and the maximum associated with the further adaptation factor may be adapted as a function of the speed. For example, at low vehicle speeds, a minimum may be selected to be smaller and a maximum greater than at higher vehicle speeds.

In a further embodiment, a first torque characteristic is associated with a first vehicle speed between 0 km / h and 5 km / h or a first speed interval between 0 km / h and 5 km / h. Preferably, the first vehicle speed is 0 km / h. Analogously, a second torque characteristic is associated with a second vehicle speed between 10 km / h and 20 km / h or a speed interval between 10 km / h and 20 km / h. Preferably, the second vehicle speed is 15 km / h. Furthermore, a third torque characteristic is assigned to a third vehicle speed between 40 km / h and 60 km / h or a third speed interval between 40 km / h and 60 km / h. Preferably, the third vehicle speed is 50 km / h. Furthermore, a fourth torque characteristic is associated with a fourth vehicle speed between 80 km / h and 100 km / h or a fourth speed interval between 80 km / h and 100 km / h. Preferably, the fourth vehicle speed is 90 km / h. Further, a fifth vehicle speed is associated with a fifth torque characteristic between 130 km / h and 250 km / h or a fifth speed interval between 130 km / h and 250 km / h. Preferably, the fifth vehicle speed is 130 km / h. This advantageously allows an improved adaptation of a determination of a desired assist torque over characteristic speed intervals or characteristic vehicle speeds, a parking operation (first vehicle speed or first speed interval), a pedestrian (second vehicle speed or second speed interval), a city trip (third vehicle speed or third speed interval), a highway trip (fourth vehicle speed or fourth speed interval), and a highway travel (fifth vehicle speed or fifth speed interval, respectively).

Further proposed is a device for determining a desired assist torque in a steering system. The device comprises at least one central evaluation and control unit, at least one device for detecting a manual torque, at least one device for detecting a vehicle speed, at least one memory device and at least one input device. By means of a proposed device, one of the previously described methods can be carried out in an advantageous manner. In particular, the first and the at least one further torque characteristic can be stored or stored in the memory device. Further preferably, a desired adaptation factor can be entered by means of the input device.

In a further embodiment, the first and the at least one further torque characteristic can be set as a function of an adjustable profile, wherein the adjustable profile can be selected from at least two profiles by means of the at least one input device or a further input device. This results in the simplest possible adjustability of a general profile, which reflects a generally desired steering behavior in an advantageous manner.

Further proposed is a steering system, wherein the steering system comprises at least one actuator for generating a support torque. According to the invention, the steering system comprises a previously described device, wherein by means of a central evaluation and control unit, an input variable of the actuator for generating a support torque in dependence on the target assist torque is determinable and adjustable. This results in an advantageous manner by means of the previously described method operated steering system.

The invention will be explained in more detail with reference to an embodiment. The figures show:

1 a schematic block diagram of a device according to the invention for determining a desired assist torque and

2 a schematic flow diagram of a method according to the invention for determining a desired assist torque.

Hereinafter, like reference numerals designate elements having the same or similar technical characteristics.

In 1 is a schematic block diagram of an inventive device for determining a target assist torque M _R (see 2 ). An inventive steering system 1 comprises a steering handle formed as a steering wheel 2 , a torque sensor 3 for detecting a hand torque M _H , a steering column 4 and a rack 5 , Next includes the steering system 1 an electromechanical actuator 6 for generating a support torque. The steering column 4 and the electromechanical actuator 6 are about gear 7 with the rack 5 mechanically coupled. Next includes the steering system 1 a rotor position sensor 8th for detecting a rotor position φ. Next includes the steering system 1 a central evaluation and control unit 9 , a vehicle speed sensor 10 , a storage device 11 and an input device 12 , which may be formed for example as a touch screen. In the storage device 11 are moment characteristic curves 13a . 13b . 13c . 13d . 13e saved (see 2 ). By means of the vehicle speed sensor 10 is a vehicle speed v detectable. Depending on the vehicle speed v and the manual torque M _H determines the central evaluation and control device 9 a target assist torque M _R and generates an input variable in its dependence, z. B. an input current i _S , the electromechanical actuator 6 , Furthermore, the central evaluation and control device controls a rotor position φ of the electromechanical actuator 6 , Thus, the input variable, so the input current i _S , as a reference variable for a control loop for controlling the rotor position φ.

In 2 is a schematic flow diagram of a method according to the invention for determining a target assist torque M _R shown. In a first step S1, a current manual torque M _H , for example by means of a torque sensor 3 (please refer 1 ) detected. In a second step S2, an actual vehicle speed v z. B. by means of a vehicle speed sensor 10 (please refer 1 ) detected. In a third step S3, a first and a second provisional support torque M _V1 , M _{V2 are determined} as a function of the current manual torque M _R and the current vehicle speed v. For this purpose are in a storage device 11 (please refer 1 ) a first, second, third, fourth and fifth torque characteristic 13a . 13b . 13c . 13d . 13e stored, each of a first, second, third, fourth and fifth vehicle speed v1, v2, v3, v4, v5 are assigned. For example, the first torque characteristic is 13a associated with the first vehicle speed v1. In the following it is assumed that the current vehicle speed v is greater than the first vehicle speed v1, but less than the second vehicle speed v2. Thus, the first preliminary assist torque M _V1 becomes dependent on the current manual torque M _H and the first torque characteristic 13a certainly. In parallel, the second provisional assisting torque M _V2 becomes dependent on the current hand torque M _H and the second torque characteristic curve 13b certainly. The torque curves 13a . 13b . 13c . 13d . 13e hereby show each other different courses. The first, second, third, fourth and fifth torque characteristic 13a . 13b . 13c . 13d . 13e respectively serves to determine a first, second, third, fourth and fifth provisional assist torque M _V1 , M _V2 , M _V3 , M _V4 , M _V5 . In a fourth step S4 z. B. by means of an input device 12 (please refer 1 ) evaluated adaptation factors F1, F2 evaluated. A first adapted assist torque M _{A1 is} determined from the product of the first provisional assist torque M _V1 , and the first adaptation factor F1, which is also associated with the first vehicle speed v1. Analogously, a second adapted assisting torque M _{A2 is determined} from the product of the second provisional assisting torque M _V2 and the second adaptation factor F2 associated with the second vehicle speed v2.

In a fifth step S5, the resulting target assist torque M _{R is determined} as a function of the first and the at least one further adapted assist torque M _A1 , M _V2 and the current vehicle speed v, for example as a function of the vehicle speed v between the first and the second adapted Support moment M _A1 , M _A2 interpolated value. In a sixth step S6, an input current i _S can be determined and set as a function of the desired assistance torque M _R.

The in 2 illustrated set of moment characteristics 13a . 13b . 13c . 13d . 13e is a function of one of a motor vehicle driver by means of the input device 12 adjustable profile, the profile from the group "normal", "comfortable", "sporty" is selectable.

LIST OF REFERENCE NUMBERS

1

steering system

2

Steering handle

3

torque sensor

4

steering column

5

rack

6

electromechanical actuator

7

transmission

8th

Rotor position sensor

9

Central evaluation and control unit

10

Vehicle speed sensor

11

memory device

12

input device

S1

first step

S2

second step

S3

Third step

S4

fourth step

S5

fifth step

S6

sixth step

M _H

manual torque

v

vehicle speed

i _p

input current

φ

rotor position

v1

first vehicle speed

v2

second vehicle speed

v3

third vehicle speed

v4

fourth vehicle speed

v5

fifth vehicle speed

M _V1

first preliminary support moment

M _V2

second provisional support moment

M _V3

third provisional support moment

M _V4

fourth preliminary support moment

M _V5

fifth provisional support moment

13a

first torque characteristic

13b

second torque characteristic

13c

third torque characteristic

13d

fourth torque characteristic

13e

fifth torque characteristic

F1

first adaptation factor

F2

second adaptation factor

M _A1

first adapted assisting moment

M _A2

second adapted assist moment

M _R

Target assist torque

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• US 2005/0140322 A1 [0004]
• DE 102006017714 A1 [0005]
• DE 102008006847 A1 [0006]

Claims (9)

Method for determining a desired assist torque (M _R ) in a steering system ( 1 ), wherein the target assist torque (M _R ) is determined at least in response to a manual torque (M _H ) and a vehicle speed (v), wherein a first vehicle speed (v1) or a first speed interval, a first torque characteristic ( 13a ), wherein the first torque characteristic ( 13a ) represents a relationship between the manual torque (M _H ) and the assist torque, wherein a first preliminary assist torque (M _V1 ) than that of the first torque characteristic (M) ( 13a ), wherein the first vehicle speed (v1) or the first speed interval is associated with a first adjustable adaptation factor (F1), wherein a first adapted assist torque (M _A1 ) as product of the first provisional assist torque (M _V1 ) and the first adaptation factor (F1), characterized in that at least one further vehicle speed (v2, v3, v4, v5) or at least one further speed interval has a further torque characteristic ( 13b . 13c . 13d . 13e ), wherein a further provisional assist torque (M _V2 , M _V3 , M _V4 , M _V5 ) than that from the further torque characteristic ( 13b . 13c . 13d . 13e ) is determined, wherein the at least one further vehicle speed (v2, v3, v4, v5) or the further speed interval, a further adaptation factor (F2) is assigned, wherein at least one further adapted assisting torque (M _A2 ) as a product of the at least one further provisional support torque (M _V2 ) and the at least one further adaptation factor (F2) is determined, wherein the target assist torque (M _R ) in dependence of the first and the at least one further adapted assist torque (M _A1 , M _A2 ) is determined. Method according to Claim 1, characterized in that the first torque characteristic ( 13a ) of the at least one further torque characteristic ( 13b . 13c . 13d . 13e ) is different. Method according to one of claims 1 or 2, characterized in that the target assist torque (M _R ) is determined as a function of the vehicle speed (v) interpolated value between the first and the at least one further adapted assist torque (M _A1 , M _A2 ) , Method according to one of the preceding claims, characterized in that the first and the at least one further characteristic ( 13a . 13b . 13c . 13d . 13e ) depending on an adjustable profile, wherein the adjustable profile is selected from at least two profiles. Method according to one of the preceding claims, characterized in that an adjustment of the first adaptation factor (F1) is limited to a minimum associated with the first adaptation factor (F1) and a maximum associated with the first adaptation factor (F1) and / or an adjustment of the at least one further Adaptation factor (F2) is limited to the at least one further adaptation factor (F2) associated minimum and the at least one further adaptation factor (F2) associated maximum. Method according to one of the preceding claims, characterized in that a first vehicle speed (v1) between 0 km / h and 5 km / h or a first speed interval between 0 km / h and 5 km / h has a first torque characteristic ( 13a ) and a second vehicle speed (v2) between 10 km / h and 20 km / h or a second speed interval between 10 km / h and 20 km / h a second torque characteristic ( 13b ) and a third vehicle speed (v3) between 40 km / h and 60 km / h or a third speed interval between 40 km / h and 60 km / h a third torque characteristic ( 13c ) and a fourth vehicle speed (v4) between 80 km / h and 100 km / h or a fourth speed interval between 80 km / h and 100 km / h a fourth torque characteristic ( 13d ) and a fifth vehicle speed (v5) between 130 km / h and 250 km / h or a fifth speed interval between 130 km / h and 250 km / h a fifth torque characteristic ( 13e ) assigned. Device for determining a desired assist torque (M _R ) in a steering system ( 1 ), wherein the device has at least one central evaluation and control device ( 9 ), at least one device for detecting a manual torque (M _H ), at least one device for detecting a vehicle speed (v), at least one memory device ( 11 ) and at least one input device ( 12 ), wherein the desired assist torque (M _R ) is determinable at least as a function of a manual torque (M _H ) and a vehicle speed (v), wherein a first vehicle speed (v1) or a first speed interval has a first torque characteristic ( 13a ), wherein the first torque characteristic ( 13a ) represents a relationship between the manual torque (M _H ) and the assist torque, wherein a first preliminary assist torque (M _V1 ) by means of the central evaluation and control device ( 9 ) than that from the first torque characteristic ( 13a ) is determined, wherein the the first vehicle speed (v1) or the first speed interval, a first adjustable adaptation factor (F1) is assigned, wherein the first adjustable adaptation factor (F1) by means of the at least one input device ( 12 ) is adjustable, wherein by means of the central evaluation and control device ( 9 ) a first adapted assist torque (M _A1 ) as a product of the first provisional assist torque (M _V1 ) and the first adaptation factor (F1) can be determined, characterized in that at least one further vehicle speed (v2, v3, v4, v5) or at least one other Velocity interval another torque characteristic ( 13b . 13c . 13d . 13e ), wherein by means of the central evaluation and control device ( 9 ) another provisional assist torque (M _V2 , M _V3 , M _V4 , M _V5 ) than that from the further torque characteristic ( 13b . 13c . 13d . 13e ), the at least one further vehicle speed (v2, v3, v4, v5) or the further speed interval, a further adjustable adaptation factor (F2) is assigned, wherein the at least one further adjustable adaptation factor (F2) by means of the at least one input device ( 12 ) is adjustable, wherein by means of the central evaluation and control device ( 9 ) at least one further adapted assist torque (M _A1 , M _A2 ) can be determined as a product of the at least one additional provisional assist torque (M _V2 ) and the at least one further adaptation factor (F2), wherein by means of the central evaluation and control device ( 9 ) the desired assist torque (M _R ) in dependence on the first and the at least one further adapted assist torque (M _A1 , M _A2 ) can be determined. Apparatus according to claim 7, characterized in that the first and the at least one further torque characteristic ( 13a . 13b . 13c . 13d . 13e ) is adjustable in dependence on an adjustable profile, wherein the adjustable profile by means of the at least one input device ( 12 ) or another input device from at least two profiles is selectable. Steering system, the steering system ( 1 ) comprises at least one actuator for generating an assist torque, characterized in that the steering system ( 1 ) comprises a device according to one of claims 7 or 8, wherein by means of the central evaluation and control device ( 9 ) An input variable of the actuator for generating an assist torque in dependence on the target assist torque (M _R ) is determinable and adjustable.

Images