Method and control apparatus for operating an actuator of a steer-by-wire steering system of a motor vehicle

Patent metadata

Field	Value
Publication number	US-2024067266-A1
Application number	US-202118261375-A
Country	US
Kind code	A1
Filing date	Oct 26, 2021
Priority date	Jan 15, 2021
Publication date	Feb 29, 2024
Grant date	—

Abstract

A method is provided for operating an actuator of a steer-by-wire steering system of a motor vehicle in a speed range from standstill to parking and/or maneuvering. In one example, the method includes detecting an instantaneous speed of the motor vehicle, determining a limited steering angle as a function of at least the instantaneous speed, detecting a steering angle demand, and activating an actuator for setting a steering angle of at least one wheel, at least as a function of the steering angle demand and having regard to the limited steering angle.

First claim

1 . Method for operating an actuator of a steer-by-wire steering system ( 4 , 5 ) of a motor vehicle ( 1 ) at speeds from standstill to parking and/or maneuvering speeds, wherein the method comprises the following steps:
detecting an instantaneous speed (v_mom) of the motor vehicle; determining a limited steering angle (RLw_lim_mom) as a function of at least the instantaneous speed (v_mom); detecting a steering angle demand (Lw_req); and activating an actuator for setting a steering angle (RL Wv , RL Wh ) of at least one wheel, at least as a function of the steering angle demand (Lw_req) and taking into account the limited steering angle (RLw_lim_mom).

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

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

4 . The method according to claim 1 , wherein determining the limited steering angle (RLw_lim_mom) includes setting a first steering angle range (Lw 1 ) from 0° up to less than or equal to the limited steering angle (RLw_lim_mom) and setting a second steering angle range (Lw 2 ) larger than the limited steering angle (RLw_lim_mom) up to the predefined maximum steering angle (RLw_max), and wherein at a speed of the motor vehicle from standstill up to a first speed (v 1 ) the steering angle (RL Wv , RL Wh ) to be set can adopt any value in the first steering angle range (Lw 1 ).

5 . The method according to claim 4 , comprising:
driving at a speed higher than the first speed (v 1 ); subsequently reverting to and remaining in the first speed range (v_ 0 - 1 ); and setting a most recently set steering angle (RLw_rec_Lw 2 ) from the second steering angle range (Lw 2 ) as a new limited steering angle (RLw_lim_Lw 2 ).

6 . The method according to claim 5 , comprising:
reverting to and remaining in the first speed range (v_ 0 - 1 ); and receiving a new steering angle demand (Lw_req), the new steering angle demand being larger than 50% to 80% of the predefined maximum steering angle (RLw_max), wherein the new limited steering angle is in a range of 50% to 80% of the predefined maximum steering angle (RLw_max) and not greater than the retained limited steering angle (RLw_lim_Lw 2 ).

7 . The method according to claim 4 , comprising:
cancelling the limited steering angle (RLw_lim_mom, RLw_lim_Lw 2 ) at a speed higher than the first speed (v 1 ), and setting the steering angle (RL Wv , RLw), after detecting the steering angle demand (Lw_req), in the step of activating the actuator to a value up to the predefined maximum steering angle (RLw_max).

8 . The method according to claim 1 , comprising:
setting a new steering angle (RL Wv , RL Wh ) starting from a previously set steering angle as a function of the instantaneous speed (v_mom), wherein the steering angle demand (Lw_req) 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 instantaneous speed (v_mom), in the step of determining the limited steering angle (RLw_lim_mom).

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 . Control A control unit (SG) for controlling an actuator of a steer-by-wire steering system ( 4 , 5 ) of a motor vehicle ( 1 ), comprising:
an interface configured to detect a speed (v_mom) that represents an instantaneous speed of the motor vehicle; a further interface configured to detect a steering angle demand (Lw_req), which represents an instantaneous steering angle change due to a driver's wish or due to a further change of a steering angle determined by a control unit (SG); a unit configured to determine a limited steering angle (RLw_lim_mom), which represents an instantaneous maximum possible steering angle; and a unit configured to activate the actuator in order to set a steering angle (RL Wv , RL Wh ) of at least one wheel as a function of at least of the steering angle demand (Lw_req) and having regard to the limited steering angle (RLw_lim_mom).

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 . (canceled)

14 . The method according to claim 4 , wherein the first speed (v 1 ) is from 0.5 to 1 km/h.

15 . The method according to claim 4 , wherein the first speed (v 1 ) is not greater than 0.7 km/h.

Assignees

• Zahnradfabrik Friedrichshafen

Inventors

• Dasch Ingo
• Vogt Dominik
• Diebold Luc
• Rau Magnus
• Spangemacher Björn

Classifications

• B62D7/159 Primary

  characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition · CPC title

• B62D6/02

  responsive only to vehicle speed · CPC title

• B62D6/002

  computing target steering angles for front or rear wheels (B62D7/159 takes precedence) · CPC title