Method for steering a vehicle with superimposed steering

• US 20050251310A1
• Filed: 07/03/2003
• Published: 11/10/2005
• Est. Priority Date: 07/05/2002
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Bohm, Jurgen
• Granted Patent: US 7,548,807 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B62D 5/008 Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence

Abstract

A method of steering a vehicle with a superimposed steering system, wherein a steering angle input by the driver and an additional angle (additional steering angle) is determined and wherein the additional steering angle can override the input steering angle according to further quantities, in particular diving-dynamics quantities, by means of an electric motor, is characterized in that the method includes a steering angle control with a subordinated current or torque control of the electric motor.

Claims

1-12. -12. (canceled)

13. Method of steering a vehicle with a superimposed steering system, wherein a steering angle input by the driver and an additional angle (additional steering angle) is determined and wherein the additional steering angle can override the input steering angle according to further quantities, by means of an electric motor,

wherein the method includes a steering angle control with a subordinated current or torque control of the electric motor.

14. Method as claimed in claim 13,

wherein an actual steering angle value and a nominal steering angle value is determined and, according to a comparison between the actual steering angle value and the nominal steering angle value, a nominal current or a nominal motor torque is produced by which the electric motor introduces the additional steering angle into the steering system.

15. Method as claimed in claim 13,

wherein a steering request of the driver δ

_DRV 52 is determined on the basis of a steering wheel angle δ

_H 50 adjusted by the driver, and wherein the driver'"'"'s steering request δ

_DRV 52 is composed of the adjusted steering wheel angle δ

_H 50 and an invariably or variable predeterminable gear ratio factor and the gear ratio factor is chosen corresponding to the current driving situation, and wherein a nominal steering angle value 53 δ

_nominal is determined on the basis of the so calculated steering request of the driver and sent to the steering control.

16. Method as claimed in claim 13,

wherein the driver'"'"'s steering angle δ

_H is determined and, in connection with a gear ratio factor i_L1 by which the driver'"'"'s steering angle acts directly on the steering gear, an additional steering angle δ

_M is additively superimposed thereon in connection with a second gear ratio i_L2, and wherein a superimposed steering angle δ

_L is determined and sent as an actual value δ

_L,actual to the steering control, with said superimposed steering angle δ

_L being determined according to the following formula;

δ

_L=i_L1*δ

_H+i_L2*δ

_M.

17. Method as claimed in claim 13,

wherein a driving dynamics control (ESP system) cooperates with the steering control, and wherein an additional steering angle Δ

δ

56 responsive to driving dynamics is determined when the necessity of a stabilizing intervention is detected by driving dynamics control.

18. Method as claimed in claim 13,

the method further comprising a driving dynamics control (ESP system) cooperates with the steering control, and an additional steering angle Δ

δ

56 responsive to driving dynamics is determined when the necessity of a stabilizing intervention is detected by driving dynamics control,

wherein the additional steering angle Δ

δ

56 responsive to driving dynamics that is produced on the basis of a correcting intervention of a driving dynamics controller 57 is additively superimposed on the driver'"'"'s steering request δ

_DRV 52.

19. Method as claimed in claim 13,

wherein the electric motor is additionally actuated by means of a field weakening current according to further quantities, with a view to increasing the motor speed without reduction of the available motor torque.

20. Method as claimed in claim 13,

the method further comprising the electric motor is additionally actuated by means of a field weakening current according to further quantities, with a view to increasing the motor speed without reduction of the available motor torque,

wherein the electric motor is additionally actuated by means of a field weakening current when a very direct steering ratio and/or a high nominal speed is desired or required.

21. Method as claimed in claim 13,

wherein based on the series steering ratio i_L,series and due to a boosting factor K1 responsive to a steering wheel angle and a boosting factor K2 responsive to the vehicle speed, a resulting steering ratio I_L,ESAS which corresponds to the ratio between the steered wheels δ

_V and the driver'"'"'s steering angle δ

_H is determined according to the following formula;

i_L,ESAS=δ

_V/δ

_H=i_L,series/(K1*K2).

22. Method as claimed in claim 13,

wherein an anticipatory control of the nominal speed of the motor ω

_M,nominal is executed, which is determined from a motor speed specification ω

_M,Spec and a motor speed preset value ω

_M,reg, and the motor speed preset value 107 _M,reg is determined on the basis of a comparison between a nominal steering angle value δ

_L,nominal and a determined actual steering angle value δ

_L,actual, and the motor speed specification

coM,spec is determined from the time derivative of the nominal steering angle value δ

_L,nominal and the driver'"'"'s steering angle δ

_H and a gear ratio factor i_L2 by means of the following formula;

ω

_M,spec=(δ

_L,nominal−

i_L1δ

_H)/i_L2.

23. Computer program,

which is suitable for implementing a method of steering a vehicle with a superimposed steering system, wherein a steering angle input by the driver and an additional angle (additional steering angle) is determined and wherein the additional steering angle can override the input steering angle according to further quantities, by means of an electric motor,

wherein the method includes a steering angle control with a subordinated current or torque control of the electric motor.