Steer-by-wire system with first and second steering actuators

• US 6,681,881 B2
• Filed: 08/13/2001
• Issued: 01/27/2004
• Est. Priority Date: 08/11/2000
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Husain, Muqtada, Andonian, Brian J., Radamis, Maged, Stout, Gregory J., Zheng, Bing, Yao, Yixin
• Primary Examiner(s): Morris, Lesley D.
• Assistant Examiner(s): LUM VANNUCCI, LEE SIN YEE
• Application Number:
  US09/928,841
• Publication Number:
  US 20020070070A1
• Time in Patent Office: 897 Days
• Field of Search: 180/402, 180/403, 180/421, 180/422, 180/443-446, 701/41, 701/42
• US Class Current: 180/402
• CPC Class Codes: B62D 5/001 Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup
• 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 steer-by-wire system of the preferred embodiment of the invention includes a steering sensor, a turning subsystem, a vehicle sensor, and a controller subsystem. The turning subsystem further includes a first turning actuator to adjust a turning angle of a first road wheel, a first turning sensor to sense first turning factors of the first turning actuator, a second turning actuator to adjust a turning angle of a second road wheel, and a second turning sensor to sense second turning factors of the second turning actuator. The controller subsystem is connected to the steering sensor, to the first turning sensor, to the second turning sensor, and to the vehicle sensor. The control subsystem independently controls the first turning actuator and the second turning actuator.

Claims

1. A steer-by-wire system for a vehicle having a first front wheel capable of turning, a second front wheel capable of turning, and a steering device capable of receiving a steering input from a driver of the vehicle, comprising:

a steering sensor coupled to the steering device and adapted to sense steering factors of the steering input;

a turning subsystem including a first turning actuator coupled to the first front wheel and adapted to receive a first turning control signal and to adjust a turning angle of the first front wheel, a first turning sensor coupled to said first turning actuator and adapted to sense first turning factors of said first turning actuator, a second turning actuator coupled to the second front wheel and adapted to receive a second turning control signal end to adjust a turning angle of the second front wheel, and a second turning sensor coupled to said second turning actuator and adapted to sense second turning factors of said second turning actuator, said turning first factors include a current draw of said first actuator and a temperature of said first actuator, said second turning factors include a current draw of said second turning actuator and a temperature of said second turning actuator;

a vehicle sensor coupled to the vehicle and adapted to sense vehicle factors of the vehicle; and

a controller subsystem connected to said steering sensor, to said first turning sensor, to said second turning sensor, and to said vehicle sensor, and adapted to produce the first turning signal based on the steering factors, the first turning factors, and the vehicle factors thereby controlling the turning angle of the first front wheel and to produce the second turning signal based on the steering factors, the second turning factors, and the vehicle factors thereby independently controlling the turning angle of the second front wheel.

2. A steer-by-wire system for a vehicle of claim 1, further comprising a steering actuator coupled to the steering device and adapted to receive a steering feedback signal and to generate a steering feedback to the driver, wherein said controller subsystem is further adapted to produce the steering feedback signal based on the steering factors, the first turning factors and the second turning factors thereby controlling the steering feedback of the steering device.

3. A steer-by-wire system for a vehicle of claim 2, wherein said steering actuator includes an electric motor to generate the steering feedback.

4. A steer-by-wire system for a vehicle of claim 2, wherein said steering actuator includes a magneto-rheological device to generate the steering feedback.

5. A steer-by-wire system for a vehicle of claim 1, wherein steering factors include steering angle and steering torque.

6. A steer-by-wire system for a vehicle of claim 1, wherein said vehicle factors include vehicle speed, vehicle lateral acceleration and vehicle yaw rate.

7. A steer-by-wire system for a vehicle of claim 6, wherein said vehicle factors also include ignition mode.

8. A steer-by-wire system for a vehicle of claim 7, wherein said vehicle factors also include vehicle roll and vehicle pitch.

9. In a steer-by-wire system for a vehicle having a first front wheel capable of turning, a first turning actuator capable of adjusting the turning angle of the first front wheel, a second front wheel capable of turning, a second turning actuator capable of adjusting the turning angle of the second front wheel, and a steering device capable of receiving a steering input from a driver of a vehicle, a method of controlling the first front wheel and the second front wheel comprising:

sensing steering factors of the steering input and determining the steering intent of the driver;

sensing vehicle factors of the vehicle, sensing first turning factors of the first turning actuator, sensing second turning factors of the second turning actuator;

determining a current dynamic status of the vehicle, said sensing first turning factors includes sensing a current draw of the first turning actuator and sensing a temperature of the first turning actuator, said second turning factors include sensing a current draw of the second turning actuator and sensing a temperature of the second turning actuator;

comparing the steering intent and the current dynamic status;

producing a first turning control signal for the first turning actuator based on the steering factors, the vehicle factors, and the first turning factors to control the turning angle of the first front wheel; and

producing a second turning control signal for the second turning actuator based on the steering factors, the vehicle factors, and the second turning factors to independently control the turning angle of the second front wheel.

10. In a steer-by-wire system for a vehicle of claim 9, wherein said sensing steering factors includes sensing steering angle and steering torque.

11. In a steer-by-wire system for a vehicle of claim 9, wherein said sensing vehicle factors include sensing vehicle speed, vehicle lateral acceleration, and vehicle yaw rate.

12. In a steer-by-wire system for a vehicle of claim 11, wherein said sensing vehicle factors further includes sensing ignition mode.

13. In a steer-by-wire system for a vehicle of claim 11, wherein said sensing vehicle factors further includes sensing vehicle roll and vehicle pitch.