Steering system and method for a vehicle

• US 6,474,436 B1
• Filed: 07/23/1999
• Issued: 11/05/2002
• Est. Priority Date: 07/23/1998
• Status: Expired due to Fees

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Konigorski, Ulrich
• Primary Examiner(s): Olszewski, Robert P.
• Assistant Examiner(s): Fischer, Andrew J.
• Application Number:
  US09/360,243
• Time in Patent Office: 1,201 Days
• Field of Search: 180/402, 180/494, 180/446, 180/447, 180/443, 701/42
• US Class Current: 180/402
• CPC Class Codes: B62D 5/006 power actuated
• CPC Class Codes: B62D 6/008 Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications

Abstract

A steering system for a vehicle has a steering operating device, an operating moment sensor which is assigned to the steering operating device and which senses the operating moment exercised on the steering operating device and generates a corresponding signal, and a steering angle sensor which senses a steering angle corresponding to the alignment of the steerable wheels and supplies a corresponding signal to a control unit which, in turn, determines a pertaining desired angle of the steering operating device. The control unit is constructed in order to process the signal generated by the operating moment sensor and emit an assigned desired steering moment or an assigned desired steering force. A steering device, which is mechanically uncoupled from the steering operating device, sets the desired steering moment or the desired steering force at the steerable wheels. A feedback unit is provided for setting the determined desired angle at the steering operating device.

Claims

1. A steering system for a vehicle, comprising:

a manually operated steering operation device;

an operating moment sensor coupled to the steering operation device and generating a first signal corresponding to an operating moment exercised on the steering operation device;

a control unit receiving the first signal generated by the operating moment sensor and emitting a second signal corresponding to an assigned desired steering moment or an assigned desired steering force;

a steering device coupled to steerable wheels and mechanically uncoupled from the steering operation device, receiving the second signal corresponding to the assigned desired steering moment or the assigned desired steering force from the control unit and operating the steerable wheels so that the assigned desired steering moment or the assigned desired steering force is set at the steerable wheels;

a steering angle sensor coupled to the steerable wheels and supplying a third signal corresponding to an alignment of the steerable wheels to the control unit which, in turn, determines a pertaining desired angle of the steering operation device and generates a corresponding fourth signal; and

a feedback unit coupled to the steering operation device, receiving the fourth signal corresponding to the desired angle of the steering operation device and outputting a fifth signal as a function of said fourth signal corresponding to the desired angle of the steering operation device to operate the steering operation device so that the desired angle is set at the steering operation device.

2. The steering system according to claim 1, wherein the steering device comprises a steering moment sensor which senses an actual steering moment or an actual steering force present at the steerable wheels, and further wherein the steering device adjusts the actual steering moment to the desired steering moment or the actual steering force to the desired steering force.

3. The steering system according to claim 1, further comprising an angle of rotation sensor which senses the actual angle of rotation present at the steering operation device, and further wherein the feedback unit adjusts the actual angle of rotation to the desired angle.

4. The steering system according to claim 3, further comprising an actuator and an elastic connector, the elastic connector coupling the steering operation device and the actuator.

5. The steering system according to claim 2, further comprising an angle of rotation sensor which senses the actual angle of rotation present at the steering operation device, and further wherein the feedback unit adjusts the actual angle of rotation to the desired angle.

6. The steering system according to claim 5, comprising an actuator and an elastic connector, the elastic connector coupling the steering operation device and the actuator.

7. The steering system according to claim 1, wherein said system is a power steering system.

8. The steering system according to claim 1, wherein at least two elements of the steering system are provided in a redundant manner.

9. The steering system according to claim 1, further comprising a steering linkage connecting the steerable wheels with one another.

10. The steering system according to claim 1, wherein each one of the steerable wheels is separately steerable.

11. The steering system according to claim 1, wherein the control unit computes at least one of the desired steering moment and the desired steering angle such that a virtual elasticity is created between an input and a wheel-road effect.

12. The steering system according to claim 1, wherein the control unit receives and factors into account at least one additional parameter when forming at least one of the desired steering moment and the desired angle.

13. The steering system according to claim 12, wherein the at least one additional parameter is at least one of a vehicle speed, a yaw rate, a slip angle, a road condition and-a lateral acceleration.