Vehicle motion control system

• US 5,869,943 A
• Filed: 10/21/1997
• Issued: 02/09/1999
• Est. Priority Date: 10/23/1996
• Status: Expired due to Term

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Mihara, Jun, Terada, Hitoshi, Nakashima, Hiroshi, Hamada, Toshiaki
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Leykin, Rita
• Application Number:
  US08/967,329
• Time in Patent Office: 476 Days
• Field of Search: 364/426, 364/424, 364/426.01, 303/100, 303/146, 701/82, 701/70, 701/183
• US Class Current: 318/586
• CPC Class Codes: B60T 2230/03 Overturn, rollover
• CPC Class Codes: B60T 8/17554 specially adapted for enhancing stability around the vehicles longitudinal axle, i.e. roll-over prevention road vehicle drive control systems for roll-over prevention otherwise than by controlling a particular sub-unit B60W30/04
• CPC Class Codes: B60T 8/241 Lateral vehicle inclination
• CPC Class Codes: B60T 8/246 Change of direction
• CPC Class Codes: B60T 8/4827 in hydraulic brake systems

Abstract

The present invention is directed to a vehicle motion control system for maintaining vehicle stability, even in the case where the vehicle is tilted when the vehicle is in turning motion, wherein a braking force control unit is provided for controlling a braking force applied to each of front and rear wheels of the vehicle. The system includes a tilt detection unit which detects a tilt of a normal axis of the vehicle to its vertical axis, and a turn determination unit which determines a turning condition of the vehicle including a turning direction thereof. A yaw moment control unit is provided for controlling the braking force controlling unit to produce a yaw moment in a direction opposite to the turning direction of the vehicle in response to the tilt detected by the tilt detection unit when the turn determination unit determines that the vehicle is turning.

Claims

1. A vehicle motion control system for maintaining stability of an automotive vehicle when said vehicle is in a turning motion, comprising:

braking force controlling means for controlling a braking force applied to each of front wheels and rear wheels of said vehicle;

tilt detection means for detecting a tilt of a normal axis of said vehicle to a vertical axis of said vehicle;

turn determination means for determining a turning condition of said vehicle including a turning direction of said vehicle; and

yaw moment control means for controlling said braking force controlling means to produce a yaw moment in a direction opposite to the turning direction of said vehicle in response to the tilt detected by said tilt detection means when said turn determination means determines that said vehicle is turning.

2. A vehicle motion control system as claimed in claim 1, wherein said yaw moment control means is adapted to select one of said front wheels of said vehicle located on the outside of a curve in said vehicle'"'"'s path of travel in accordance with the result of said turn determination means, and adapted to control said braking force controlling means to apply the braking force to the one of said front wheels located on the outside of the curve in said vehicle'"'"'s path of travel in response to the tilt detected by said tilt detection means.

3. A vehicle motion control system as claimed in claim 1, further comprising wheel speed detection means for detecting a wheel speed of each wheel of said vehicle, and wherein said yaw moment control means includes:

desired slip rate setting means for setting a desired slip rate for each wheel of said vehicle in response to the tilt detected by said tilt detection means;

actual slip rate measuring means for measuring an actual slip rate of each wheel of said vehicle; and

slip rate deviation calculating means for calculating a deviation between the desired slip rate and the actual slip rate, said yaw moment control means controlling said braking force controlling means in response to the deviation calculated by said slip rate deviation calculating means.

4. A vehicle motion control system as claimed in claim 1, further comprising:

driving force controlling means for controlling a driving force applied to said vehicle; and

speed decreasing means for controlling at least one of said braking force controlling means and said driving force controlling means to decrease a speed of said vehicle in response to the tilt detected by said tilt detection means when said turn determination means determines that said vehicle is turning.

5. A vehicle motion control system as claimed in claim 4, wherein said yaw moment control means is adapted to select one of said front wheels of said vehicle located on the outside of the curve in said vehicle'"'"'s path of travel in accordance with the result of said turn determination means, and adapted to control said braking force controlling means to apply the braking force to the one of said front wheels located on the outside of the curve in said vehicle'"'"'s path of travel in response to the tilt detected by said tilt detection means.

6. A vehicle motion control system as claimed in claim 4, further comprising wheel speed detection means for detecting a wheel speed of each wheel of said vehicle, and wherein said yaw moment control means includes:

desired slip rate setting means for setting a desired slip rate for each wheel of said vehicle in response to the tilt detected by said tilt detection means;

actual slip rate measuring means for measuring an actual slip rate of each wheel of said vehicle; and

slip rate deviation calculating means for calculating a deviation between the desired slip rate and the actual slip rate, said yaw moment control means controlling said braking force controlling means in response to the deviation calculated by said slip rate deviation calculating means.

7. A vehicle motion control system as claimed in claim 1, wherein said tilt detection means is adapted to detect the tilt of said vehicle on the basis of a roll angle about a longitudinal axis of said vehicle.

8. A vehicle motion control system for maintaining stability of an automotive vehicle when said vehicle is in a turning motion, comprising:

braking force controlling means for controlling the braking force applied to each wheel of said vehicle;

driving force controlling means for controlling a driving force applied to said vehicle;

tilt detection means for detecting a tilt of a normal axis of said vehicle to a vertical axis of said vehicle;

turn determination means for determining a turning condition of said vehicle including a turning direction of said vehicle; and

speed decreasing means for controlling at least one of said braking force controlling means and said driving force controlling means to decrease a speed of said vehicle in response to the tilt detected by said tilt detection means when said turn determination means determines that said vehicle is turning.