Steer-by-wire system using semi-active actuator

• US 6,612,392 B2
• Filed: 01/22/2002
• Issued: 09/02/2003
• Est. Priority Date: 02/10/2001
• Status: Expired due to Fees

• Current Assignee: Korea Advanced Institute of Science and Technology
• Original Assignee: Korea Advanced Institute of Science and Technology
• Inventors: Park, Youngjin, Jung, Inyong
• Primary Examiner(s): Morris, Lesley D.
• Assistant Examiner(s): Lum, L.
• Application Number:
  US10/054,651
• Publication Number:
  US 20020108804A1
• Time in Patent Office: 588 Days
• Field of Search: 180/402, 180/403, 180/421, 180/422, 180/443, 180/446, 701/41, 701/42
• US Class Current: 180/402
• CPC Class Codes: B62D 5/005 means for generating torque on steering wheel or input member, e.g. feedback

Abstract

A steer-by-wire system uses a semi-active actuator in which a wheel steering motor operates vehicle wheels when a steering wheel is rotated. The steering system includes: a steering operator unit having a steering column with one end vertically connected to the center of the steering wheel, a torsion spring connected between the other end of the steering column and a vehicle body via jigs mounted to both ends thereof, a magneto-rheological brake for providing steering reaction force according to the amount of current, and rotation angle sensor coupled with one end of the steering column for detecting rotation of the steering wheel, and a torque sensor coupled with one end of the steering column for detecting torque of the steering wheel; a current regulator for controlling resistance force against rotation of the magneto-rheological brake.581 A controller is provided for controlling the current regulator according to torque data from the torque sensor, and controlling the wheel steering motor according to rotational displacement data from the rotation angle sensor.

Claims

1. A steer-by-wire system using a semi-active actuator, in which a wheel steering motor operates vehicle wheels when a steering wheel is rotated, said system comprising:

a steering operator unit having a steering column with one end vertically connected to a center of the steering wheel, a torsion spring connected between another end of said steering column and a vehicle body via jigs mounted to both ends thereof, a magneto-rheological brake for providing steering reaction force according to an amount of current, a rotation angle sensor coupled with one end of said steering column for detecting rotation of said steering wheel, and a torque sensor coupled with one end of said steering column for detecting torque of said steering wheel;

a current regulator for controlling resistance force against rotation of said magneto-rheological brake; and

a controller for controlling said current regulator according to torque data from said torque sensor, and controlling the wheel steering motor according to rotational displacement data from said rotation angle sensor.

2. The steer-by-wire system using a semi-active actuator according to claim 1, wherein said magneto-rheological brake has a rotor fixed to an outer periphery of said steering column, a plurality of cores spaced apart from said rotor by a predetermined interval and wound with coils, and a housing spaced apart from said rotor by a predetermined interval for receiving said rotor and said plurality of cores, wherein said rotor, said plurality of cores and said housing define a space for containing a magneto-rheological fluid.

3. The steer-by-wire system using a semi-active actuator according to claim 2, wherein said housing is fixed to the vehicle body to support rotation of said steering wheel.

4. The steer-by-wire system using a semi-active actuator according to claim 1, wherein said torsion spring has a double structure of springs connected in parallel, one of said springs having a diameter and a spiral direction different from those of the other.

5. The steer-by-wire system using a semi-active actuator according to claim 1, wherein said jigs are a pair arranged in a column, one of said jigs being centrally fixed to the steering wheel, and the other one of said jigs being fixed to the vehicle body.

6. A steer-by-wire system using a semi-active actuator, in which a wheel steering motor operates vehicle wheels when a steering wheel is rotated, said system comprising:

a steering operator unit having a first steering column vertically connected, to a center of the steering wheel, a second steering column connected to said first steering column, a first torsion spring connected between said first steering column and said second steering column via first jigs mounted to both ends thereof, a second torsion spring connected between said second steering column and a vehicle body via second jigs mounted to both ends thereof, a first magneto-rheological brake for comparing torque by said first torsion spring with a reference steering torque and providing resistance force to compensate for an error, a second magneto-rheological brake mounted to said second steering column for regulating torque by said first torsion spring, a first rotation angle sensor coupled with one end of said first steering column for detecting angle displacement of the steering wheel, a second rotation angle sensor coupled with one end of said second steering column for detecting angle displacement of said second steering column, and a torque sensor coupled with one end of said first steering column for detecting torque of the steering wheel;

a current regulating unit having a first current regulator for controlling resistance force against rotation of said first magneto-rheological brake, and a second current regulator for controlling resistance force against rotation of said second magneto-rheological brake; and

a controller for receiving data of said torque sensor, said first rotation angle sensor and said second rotation angle sensor to control an amount of current of said first current regulator and said second regulator and to control the wheel steering motor.

7. The steer-by-wire system using a semi-active actuator according to claim 6, wherein said first magneto-rheological brake has a rotor fixed to an outer periphery of said first steering column, a plurality of cores spaced apart from said rotor by a predetermined interval and wound with coils, and a housing spaced apart from said rotor by a predetermined interval for receiving said rotor and said plurality of cores, said rotor, said plurality of cores and said housing defining a space for containing a magneto-rheological fluid;

and

wherein said second magneto-rheological brake has a rotor fixed to an outer periphery of said second steering column, a plurality of cores spaced apart from said rotor by a predetermined interval and wound with coils, and a housing spaced apart from said rotor by a predetermined interval for receiving said rotor and said plurality of cores, said rotor, said plurality of cores and said housing defining a space for containing a magneto-rheological fluid.

8. The steer-by-wire system using a semi-active actuator according to claim 7, wherein said housing is fixed to the vehicle body to support rotation of said steering wheel.

9. The steer-by-wire system using a semi-active actuator according to claim 6, wherein said first torsion spring has a double structure of springs connected in parallel, one of said springs having a diameter and a spiral direction different from those of the other.

10. The steer-by-wire system using a semi-active actuator according to claim 6, wherein said second torsion spring has a double structure of springs connected in parallel, one of said springs having a diameter and a spiral direction different from those of the other.

11. The steer-by-wire system using a semi-active actuator according to claim 6, wherein said second torsion spring has a stiffness lower than that of said first torsion spring means.

12. The steer-by-wire system using a semi-active actuator according to claim 6, wherein said, first jigs are arranged in a column, a first one of said first jigs being centrally fixed to the steering wheel, a second one of said first jigs being centrally fixed to the vehicle body.

13. The steer-by-wire system-using a semi-active actuator according to claim 6, wherein said second jigs are arranged in a column, a first one of said second jigs being centrally fixed to the steering wheel, a second one of said second jigs being centrally fixed to the vehicle body.