Granted Patent B2

US 12,473,025 · App. 18/261,375 · Granted Nov 18, 2025

Inventors: Ingo Dasch (Gräfelfing, DE); Dominik Vogt (Meckenbeuren, DE); Luc Diebold (Magstadt, DE); Magnus Rau (Kirchheim unter Teck, DE); Björn Spangemacher (Aidlingen, DE)

Assignee: ZF Friedrichshafen AG

B62D7/159

Abstract

Claims (39)

1 . A method for operating an actuator of a steer-by-wire steering system of a motor vehicle at speeds from standstill to parking and/or maneuvering, the method comprising the following steps:

detecting a current speed of the motor vehicle, the current speed in a range from standstill to a parking and/or maneuvering speed;

determining a limited steering angle as a function of at least the current speed;

detecting a steering angle request for recording a change in a steering angle as well as a rate of change of the steering angle; and

controlling the actuator to set the steering angle of at least one wheel, at least as a function of the steering angle request and taking into account the limited steering angle so that loads within the actuator, due to a buildup of preload between a tire and a roadway and/or between the actuator and a steering linkage, are reduced.

2 . The method according to claim 1 , wherein determining the limited steering angle includes changing the limited steering angle to a value smaller than a predefined maximum steering angle.

3 . The method according to claim 2 , determining the limited steering angle includes setting the limited steering angle at 50 to 80% of the predefined maximum steering angle.

4 . The method according to claim 1 , wherein determining the limited steering angle includes setting a first steering angle range from 0° up to less than or equal to the limited steering angle (RLw_lim_mom) and setting a second steering angle range larger than the limited steering angle up to the predefined maximum steering angle, and wherein at a speed of the motor vehicle from standstill up to a first speed the steering angle can adopt any value in the first steering angle range.

5 . A method for operating an actuator of a steer-by-wire steering system of a motor vehicle at speeds from standstill to parking and/or maneuvering, the method comprising the following steps:

detecting a current speed of the motor vehicle, the current speed in a range from standstill to a parking and/or maneuvering speed;

determining a limited steering angle as a function of at least the current speed;

setting a first steering angle range from 0° up to less than or equal to the limited steering angle, wherein at a speed of the motor vehicle from standstill up to a first speed, the steering angle can adopt any value in the first steering angle range;

setting a second steering angle range larger than the limited steering angle up to the predefined maximum steering angle;

detecting a steering angle request for recording a change in a steering angle as well as a rate of change of the steering angle;

controlling the actuator to set the steering angle of at least one wheel, at least as a function of the steering angle request and taking into account the limited steering angle so that loads within the actuator are reduced due to a buildup of preload between a tire and a roadway and/or between the actuator and a steering linkage;

driving at a speed higher than the first speed;

subsequently reverting to and remaining in the first speed range; and

setting a most recently set steering angle from the second steering angle range as a new limited steering angle.

6 . The method according to claim 5 , comprising:

reverting to and remaining in the first speed range; and

receiving a new steering angle request, the new steering angle request being larger than 50% to 80% of the predefined maximum steering angle, wherein the new limited steering angle is in a range of 50% to 80% of the predefined maximum steering angle and not greater than the retained limited steering angle.

7 . The method according to claim 4 , comprising:

cancelling the limited steering angle at a speed higher than the first speed; and

setting the steering angle, after detecting the steering angle request, in the step of controlling the actuator to a value up to the predefined maximum steering angle.

8 . The method according to claim 1 , comprising:

setting a new steering angle starting from a previously set steering angle as a function of the current speed, wherein the steering angle request takes place according to a characteristic curve in order to prevent an abrupt steering angle change.

9 . The method according to claim 1 , comprising:

changing an acceleration of a drive unit of the actuator, as a function of the current speed, in the step of determining the limited steering angle.

10 . A steer-by-wire steering system having an actuator, wherein the steer-by-wire steering system is operated in accordance with the method of claim 1 .

11 . A control unit for controlling an actuator of a steer-by-wire steering system of a motor vehicle, comprising:

an interface configured to detect a speed that represents a current speed of the motor vehicle in a range from standstill to a parking and/or maneuvering speed;

a further interface configured to detect a steering angle request for recording a change in a steering angle and a rate of change in the steering angle, the steering angle demand which represents an instantaneous steering angle change due to a driver's request or due to a further change of a steering angle determined by a control unit;

a unit configured to determine a limited steering angle, which represents an instantaneous maximum possible steering angle; and

a unit configured to control an actuator in order to set a steering angle of at least one wheel as a function of at least of the steering angle request and having regard to the limited steering angle, so that loads within the actuator, due to a buildup of preload between a tire and a roadway and/or between the actuator and a steering linkage, are reduced.

12 . A computer program product, having executable code that when executed by a processor of a steer-by-wire steering system operates the actuator according to the method of claim 1 .

13 . The method according to claim 4 , wherein the first speed is from 0.5 to 1 km/h.

14 . The method according to claim 4 , wherein the first speed is not greater than 0.7 km/h.

15 . The method according to claim 5 , wherein the first speed is from 0.5 to 1 km/h.

16 . The method according to claim 5 , wherein the first speed is not greater than 0.7 km/h.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (22)