Vehicle dynamic characteristic control apparatus

• US 5,428,532 A
• Filed: 12/30/1992
• Issued: 06/27/1995
• Est. Priority Date: 01/10/1992
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Yasuno, Yoshiki
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US07/997,750
• Time in Patent Office: 909 Days
• Field of Search: 364/424.05, 364/426.01, 364/426.03, 364/424.01, 364/424.03, 303/100, 303/92, 303/109, 303/106, 303/103, 303/91, 280/142, 280/661, 280/673, 280/691, 180/140, 180/141, 180/142, 180/79.1, 180/197
• US Class Current: 701/48
• CPC Class Codes: B60T 2260/022 Rear-wheel steering; Four-wheel steering
• 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 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition

Abstract

An apparatus controls the steering angle of a pair of front or rear wheels and the braking forces to be applied to left and right wheels of at least one of the wheel pairs. The apparatus includes a control unit for calculating a target value for a dynamic parameter related to a motion of the vehicle based upon sensed vehicle operating conditions. The control unit calculates a target value for the steering angle of the one wheel pair and controls the steering angle to the calculated target value so as to bring the dynamic parameter to its target dynamic parameter value. An absolute value of the target or actual steering angle is calculated for comparison with a predetermined value. The control unit controls the second control unit to provide a difference between the braking forces applied to the left and right wheels of the one wheel pair so as to bring the dynamic parameter to the target dynamic parameter value only when the calculated absolute value exceeds the predetermined value.

Claims

1. A vehicle dynamic characteristic control apparatus for use with an automotive vehicle supported on a pair of front wheels and a pair of rear wheels, the apparatus comprising:

a first control unit for controlling a steering angle of one of the wheel pairs;

a second control unit for controlling braking forces to be applied to left and right wheels of at least one of the wheel pairs;

sensor means sensitive to opera ting conditions of the vehicle for providing sensor signals indicative of sensed vehicle operating conditions; and

a third control unit coupled to the sensor means for calculating a target value for a dynamic parameter related to a motion of the vehicle based upon the sensed vehicle operating conditions, the third control unit including first means for calculating a target value for the steering angle of the one wheel pair, second means for controlling the steering angle of the one wheel pair to the target steering angle value so as to bring the dynamic parameter to the target dynamic parameter value, third means for calculating an absolute value of the calculated target steering angle value, fourth means for comparing the calculated absolute value with a predetermined value, and fifth means for controlling the second control unit to provide a difference between the braking forces applied to the left and right wheels of the one wheel pair so as to bring the dynamic parameter to the target dynamic parameter value only when the calculated absolute value exceeds the predetermined value.

2. The vehicle dynamic characteristic control apparatus as claimed in claim 1, wherein the dynamic parameter is a vehicle yaw rate.

3. The vehicle dynamic characteristic control apparatus as claimed in claim 1, wherein the sensor means includes a first sensor sensitive to a steering wheel position for providing a signal indicative of a sensed vehicle steering condition, a second sensor sensitive to a vehicle longitudinal speed for producing a signal indicative of a sensed vehicle longitudinal speed, and a third sensor sensitive to a vehicle longitudinal acceleration for producing a signal indicative of a sensed vehicle longitudinal acceleration.

4. The vehicle dynamic characteristic control apparatus as claimed in claim 3, wherein the third control unit includes means for calculating the target dynamic parameter value from a vehicle model specifying the target dynamic parameter value as a function of the sensed vehicle steering condition, the sensed vehicle longitudinal speed and the sensed vehicle longitudinal acceleration, the vehicle model being derived from an equation of yaw motion of the vehicle and an equation of lateral motion of the vehicle.

5. The vehicle dynamic characteristic control apparatus as claimed in claim i, wherein the fifth means includes means for calculating a target braking force difference value, and means for controlling the second control unit to bring the braking force difference to the calculated target braking force difference value.

6. A vehicle dynamic characteristic control apparatus for use with an automotive vehicle supported on a pair of front wheels and a pair of rear wheels, the apparatus comprising:

a first control unit for controlling a steering angle of one of the wheel pairs;

a second control unit for controlling braking forces to be applied to left and right wheels of at least one of the wheel pairs;

sensor means sensitive to operating conditions of the vehicle for providing sensor signals indicative of sensed vehicle operating conditions; and

a third control unit coupled to the sensor means for calculating a target value for a dynamic parameter related to a motion of the vehicle based upon the sensed vehicle operating conditions, the third control unit including first means for sensing an actual value for the steering angle of the one wheel pair, second means for controlling the steering angle of the one wheel pair to the target steering angle value so as to bring the dynamic parameter to the target dynamic parameter value, third means for calculating an absolute value of the sensed actual steering angle value, fourth means for comparing the calculated absolute value with a predetermined value, and fifth means for controlling the second control unit to provide a difference between the braking forces applied to the left and right wheels of the one wheel pair so as to bring the dynamic parameter to the target dynamic parameter value only when the calculated absolute value exceeds the predetermined value.

7. The vehicle dynamic characteristic control apparatus as claimed in claim 6, wherein the dynamic parameter is a vehicle yaw rate.

8. The vehicle dynamic characteristic control apparatus as claimed in claim 6, wherein the sensor means includes a first sensor sensitive to a steering wheel position for providing a signal indicative of a sensed vehicle steering condition, a second sensor sensitive to a vehicle longitudinal speed for producing a signal indicative of a sensed vehicle longitudinal speed, and a third sensor sensitive to a vehicle longitudinal acceleration for producing a signal indicative of a sensed vehicle longitudinal acceleration.

9. The vehicle dynamic characteristic control apparatus as claimed in claim 8, wherein the third control unit includes means for calculating the target dynamic parameter value from a vehicle model specifying the target dynamic parameter value as a function of the sensed vehicle steering condition, the sensed vehicle longitudinal speed and the sensed vehicle longitudinal acceleration, the vehicle model being derived from an equation of yaw motion of the vehicle and an equation of lateral motion of the vehicle.

10. The vehicle dynamic characteristic control apparatus as claimed in claim 6, wherein the fifth means includes means for calculating a target braking force difference value, and means for controlling the second control unit to bring the braking force difference to the calculated target braking force difference value.

11. A vehicle dynamic characteristic control apparatus for use with an automotive vehicle supported on a pair of front wheels and a pair of rear wheels, the apparatus comprising:

a first control unit for controlling a steering angle of one of the wheel pairs;

a second control unit for controlling braking forces to be applied to left and right wheels of at least one of the wheel pairs;

sensor means sensitive to operating conditions of the vehicle for providing sensor signals indicative of sensed vehicle operating conditions; and

a third control unit coupled to the sensor means for calculating a target value for a dynamic parameter related to a motion of the vehicle based upon the sensed vehicle operating conditions, the third control unit including first means for calculating a target value for the steering angle of the one wheel pair, second means for controlling the steering angle of the one wheel pair to the target steering angle value so as to bring the dynamic parameter to the target dynamic parameter value, third means for calculating an absolute value of the calculated target steering angle value, fourth means for comparing the calculated absolute value with a predetermined value, and fifth means for controlling the second control unit to provide a difference between the braking forces applied to the left and right wheels of the one wheel pair so as to bring the dynamic parameter to the target dynamic parameter value only when the calculated absolute value is not less than the predetermined value.