Steering device of vehicle

• US 20050256620A1
• Filed: 07/28/2003
• Published: 11/17/2005
• Est. Priority Date: 08/02/2002
• Status: Abandoned Application

• Current Assignee: Advics Company Limited (Aisin Corp.), Daihatsu Motor Company Limited (Toyota Motor Corporation)
• Original Assignee: Advics Company Limited (Aisin Corp.), Daihatsu Motor Company Limited (Toyota Motor Corporation)
• Inventors: Masanobu, Fukami, Yakushijn, Tokio, Kato, Toshihisa
• Application Number:
  US10/522,787
• Publication Number:
  US 20050256620A1
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B62D 5/0463 calculating assisting torque from the motor based on driver input
• CPC Class Codes: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence

Abstract

A steering apparatus for a vehicle calculates an assist force F1 corresponding to a steering torque T of a driver on the basis of a table shown in Step 605 in such a manner that the assist force F1 changes in proportion to the steering torque T, and further calculates a coefficient Kt corresponding to the absolute value of an actual lateral acceleration Gy on the basis of a table shown in Step 610. The apparatus calculates a final assist force F through multiplication of the assist force F1 by the coefficient Kt, and controls an electric motor of a steering actuator so as to generate the final assist force F for the steering operation of the driver. As a result, when the absolute value of the actual lateral acceleration Gy is not less than a value Gyth, the final assist force F decreases with an increase in the absolute value, whereby abrupt steering operation by the driver can be avoided.

Claims

1. A steering apparatus for a vehicle, applied to a vehicle which has braking force control means for applying braking force to a predetermined wheel in accordance with motion condition of the vehicle so as to generate a yawing moment for stabilizing the motion condition of the vehicle, equipped with a steerable-wheel steering mechanism which changes the steering angle of steerable wheels of the vehicle in accordance with displacement of a steering member operated by a driver and which generates a quantity related to assist force for assisting the operation of the steering member in accordance with a quantity related to operating force applied to the steering member by the driver and on the basis of a predetermined characteristic, the steering apparatus comprising:

index value obtaining means for obtaining an excessive roll generating tendency index value indicating the degree of a tendency of the vehicle to roll excessively; and

steering characteristic changing means for changing the predetermined characteristic in such a manner that the assist force for a certain operating force applied to the steering member decreases with increase of the degree of the tendency of the vehicle to roll excessively indicated by the obtained excessive roll generating tendency index valve.

3. A steering apparatus for a vehicle according to claim 1, wherein the excessive roll generating tendency index value is a value based on at least one of lateral acceleration, which is a component of acceleration acting on the vehicle in a vehicle-body lateral direction, roll angle of the vehicle, and operating speed of the steering member.

2. A steering apparatus for a vehicle, applied to a vehicle which has braking force control means for applying braking force to a predetermined wheel in accordance with motion condition of the vehicle so as to generate a yawing moment for stabilizing the motion condition of the vehicle, equipped with a steerable-wheel steering mechanism which changes the steering angle of steerable wheels of the vehicle in accordance with position of a steering member operated by a driver and on the basis of a predetermined characteristic, the steering apparatus comprising:

index value obtaining means for obtaining an excessive roll generating tendency index value indicating the degree of a tendency of the vehicle to roll excessively; and

steering characteristic changing means for changing the predetermined characteristic in such a manner that the steering angle of steerable wheels for a certain position of the steering member decreases with increase of the degree of the tendency of the vehicle to roll excessively indicated by the obtained excessive roll generating tendency index value.

4. A steering apparatus for a vehicle according to claim 2, wherein the excessive roll generating tendency index value is a value based on at least one of lateral acceleration, which is a component of acceleration acting on the vehicle in a vehicle-body lateral direction, roll angle of the vehicle, and operating speed of the steering member.