Steering angle control system for vehicle

• US 5,606,502 A
• Filed: 12/23/1994
• Issued: 02/25/1997
• Est. Priority Date: 12/27/1993
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Adachi, Kazutaka, Sudo, Hideki
• Primary Examiner(s): Chin, Gary
• Application Number:
  US08/363,037
• Time in Patent Office: 795 Days
• Field of Search: 364/424.05, 280/91, 180/79.1, 180/140, 180/141, 180/142, 180/143
• US Class Current: 701/36
• 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

In a steering angle control system including a feed-forward control for producing a desired vehicle motion variable and a feedback control for suppressing disturbances, a controller calculates a corrected steering angle from a detected steering angle and a premeasured characteristic of a steering system. The desired vehicle motion variable is calculated from a vehicle speed and the corrected steering angle. The feedback control is executed according to the difference between the desired and detected vehicle motion variables. Therefore, a driver can control a vehicle with a smooth control response in spite of a non-linear characteristic of the steering system.

Claims

1. A steering angle control system for a vehicle, comprising:

a front wheel steering angle detecting means for detecting one of a steering wheel angle of a steering wheel and a steer angle of a front wheel and outputting a signal indicative of the steering angle;

a vehicle speed detecting means for detecting a speed of the vehicle;

a vehicle motion variable detecting means for detecting a vehicle motion variable of the vehicle;

a steer angle controlled variable determining means for determining a controlled variable of a steer angle according to the signal from said front wheel steer angle detecting means and the signal from said vehicle speed detecting means;

a steering angle correcting means for correcting the signal from said front wheel steering angle detecting means according to a preset map indicative of a characteristic of a steering system including the steering wheel;

a desired vehicle motion variable calculating means for calculating a desired value of the vehicle motion variable according to the corrected steering angle and the vehicle speed;

an auxiliary steer angle controlled variable determining means for determining an auxiliary controlled variable of the steer angle controlled variable according to a difference between the desired vehicle motion variable and the detected vehicle motion variable;

a steer angle controlled variable correcting means for correcting the steer angle controlled variable by adding the auxiliary steer angle controlled variable to the steer angle controlled variable; and

an actual steer angle controlling means for controlling a steer angle of a wheel to be controlled upon receiving the corrected steer angle controlled variable.

2. A steering angle control system as claimed in claim 1, wherein said vehicle motion variable detecting means includes a yaw rate sensor.

3. A steering angle control system as claimed in claim 1, wherein said vehicle motion variable detecting means includes a lateral acceleration sensor.

4. A steering angle control system as claimed in claim 1, wherein said steer angle controlled variable determining means determines a controlled variable of a steer angle of rear wheels.

5. A steering angle control system as claimed in claim 1, wherein the auxiliary steer angle controlled variable corresponds to the difference determined by means of at least one of a proportional control and an integral control.

6. A steering angle control system as claimed in claim 1, wherein said actual steer angle controlling means includes a rear wheel steer angle actuator for controlling a steer angle of rear wheels.

7. A steering angle control system for a vehicle, comprising:

a steering angle sensor detecting a steering wheel angle of a steering wheel and outputting a signal indicative of the steering angle;

a vehicle speed sensor detecting a vehicle speed and outputting a signal indicative of the vehicle speed;

a yaw rate sensor detecting a yaw rate generated in the vehicle and outputting a signal indicative of the yaw rate;

a controller receiving the signals from said steering angle sensor, said vehicle speed sensor and said yaw rate sensor, said controller including a map for obtaining a corrected steering angle according to the signal from said steering angle sensor, said controller correcting the detected steering angle from the map and the steering angle, said controller deriving a desired yaw rate from the corrected steering angle and the vehicle speed, said controller deriving a controlled variable of a rear wheel steer angle from the steering angle and the vehicle speed, said controller determining an auxiliary controlled variable for the controlled variable according to a difference between the desired yaw rate and the detected yaw rate, said controller outputting a rear wheel control signal derived by adding the controlled variable and the auxiliary controlled variable; and

a rear wheel steer angle actuator receives the rear wheel control signal and sets a steer angle of the rear wheels so that the vehicle generates a yaw rate corresponding to the desired yaw rate.