Motor vehicle steering system

• US 20070265752A1
• Filed: 05/04/2007
• Published: 11/15/2007
• Est. Priority Date: 05/09/2006
• Status: Active Grant

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Inventors: Hayama, Ryouhei, Nakano, Shiro, Kada, Tomoyasu
• Granted Patent: US 8,660,749 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence
• CPC Class Codes: B62D 6/007 adjustable by the driver, e.g. sport mode
• 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 motor vehicle steering system steers vehicle wheels in response to the operation of an operation member for steering a vehicle. The system includes a rutted road judging unit which judges whether the vehicle is driving on a rutted road or not, and a steering enhancement control unit which enhances steering of vehicle wheels in response to operation of the operation member when the rutted road judging unit judges that the vehicle is driving on a rutted road than when the rutted road judging unit judges that the vehicle is not driving on a rutted road.

Claims

1. A motor vehicle steering system which steers vehicle wheels in response to an operation of an operation member for steering a vehicle comprising:

rutted road judging unit which judges whether the vehicle is driving on a rutted road or not; and

steering enhancement control unit which enhances steering of vehicle wheels in response to operation of the operation member when the rutted road judging unit judges that the vehicle is driving on a rutted road than when the rutted road judging unit judges that the vehicle is not driving on a rutted road.

2. The motor vehicle steering system according to claim 1,

wherein the steering enhancement control unit includes a steering ratio control unit which increases ratio of steering angle of the vehicle wheels to operation amount of the operation member when traveling on a rutted road than when not traveling on a rutted road.

3. The motor vehicle steering system according to claim 2,

wherein the steering ratio control unit sets a ratio of a steering angle to operation amount of the operation member according to time differential component of the operation amount of the operation member while traveling on a rutted road.

4. The motor vehicle steering system according to claim 1, further comprising steering assist force generation unit which generates a steering assist force in accordance with operation of the operation member

wherein the steering enhancement control unit includes steering assist control unit which controls the steering assist force generation unit such that a steering assist force becomes larger when traveling on a rutted road than when not traveling on a rutted road.

5. The motor vehicle steering system according to claim 1, further comprising operation reaction force adjusting unit which adjusts an operation reaction force of the operation member,

wherein the steering enhancement control unit includes operation reaction force control unit which controls the operation reaction force adjusting unit such that an operation reaction force becomes smaller when traveling on a rutted road than when not traveling on a rutted road.

6. The motor vehicle steering system according to claim 1, wherein,

the rutted road judging unit judges whether the vehicle is driving on a rutted road or not based on operation amount of the operation member, difference in heights between left and right of the vehicle, and lateral acceleration of the vehicle.