Vehicle yaw rate control with yaw rate command limiting

• US 6,175,790 B1
• Filed: 08/24/1998
• Issued: 01/16/2001
• Est. Priority Date: 08/24/1998
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated), General Motors Corporation (General Motors Company)
• Inventors: Chin, Yuen-Kwok, Lin, William Chin-Woei, Chen, Hsien Heng, Ghoneim, Youssef Ahmed, Sidlosky, David Michael
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): PIPALA, EDWARD J
• Application Number:
  US09/138,737
• Time in Patent Office: 876 Days
• Field of Search: 701/1, 701/36, 701/48, 701/70, 701/71, 701/72, 701/73, 303/140, 303/146, 303/147, 303/155, 303/191
• US Class Current: 701/36
• CPC Class Codes: B60T 8/17555 specially adapted for enhancing driver or passenger comfort, e.g. soft intervention or pre-actuation strategies

Abstract

An improved closed-loop vehicle yaw control in which a yaw rate limit based on measured lateral acceleration is used during transient steering maneuvers to dynamically limit a desired yaw rate derived from driver steering input. A preliminary yaw rate limit is computed based on the measured lateral acceleration, and a dynamic yaw rate limit having a proper phase relationship with the desired yaw rate is developed based on the relative magnitudes of the desired yaw rate and the preliminary yaw rate limit. A two-stage process is used to develop the dynamic yaw rate limit. A first stage yaw rate limit is determined according the lower in magnitude of the desired yaw rate and the preliminary yaw rate limit, and a second stage yaw rate limit (i.e., the dynamic yaw rate limit) is determined according to the relative magnitudes of (1) the desired yaw rate and the second stage yaw rate limit, and (2) the first stage yaw rate limit and the second stage yaw rate limit. The desired yaw rate, as limited by the dynamic yaw rate limit, is then combined with the actual or estimated yaw rate to form a yaw rate error, which in turn, is used to develop a yaw rate control command for the vehicle.

Claims

1. A limited yaw rate control method in which vehicle wheels are differentially braked in response to a yaw command based on a deviation of a vehicle yaw rate from a desired yaw rate, the improvement comprising the steps of:

measuring a lateral acceleration of the vehicle;

developing a preliminary yaw rate limit based on the measured lateral acceleration;

forming a first stage yaw rate limit according to the lesser in magnitude of the desired yaw rate and the preliminary yaw rate limit, while preserving the polarity of the desired yaw rate;

forming a second stage yaw rate limit according to a peak excursion of the first stage yaw rate limit; and

limiting the desired yaw rate according to the lesser in magnitude of the second stage yaw rate limit and the desired yaw rate.

2. The improvement of claim 1, wherein the peak excursion of the first stage yaw rate limit is identified by detecting a reduction in magnitude of said first stage yaw rate limit within an envelope defined by the desired yaw rate.

3. The improvement of claim 1, including the steps of:

preserving the polarity of the measured lateral acceleration in developing said preliminary yaw rate limit; and

filtering said preliminary yaw rate limit so that said preliminary yaw rate limit has a frequency response similar to a frequency response of said desired yaw rate.

4. The improvement of claim 1, including the step of:

setting said first and second stage yaw rate limits equal to said desired yaw rate when said yaw rate control is deactivated.

5. A limited yaw rate control method in which vehicle wheels are differentially braked in response to a yaw command based on a deviation of a vehicle yaw rate from a desired yaw rate, the improvement comprising the steps of:

measuring a lateral acceleration of the vehicle;

developing a preliminary yaw rate limit based on the measured lateral acceleration;

forming a first stage yaw rate limit according to the lesser in magnitude of the desired yaw rate and the preliminary yaw rate limit, while preserving the polarity of the desired yaw rate;

forming a second stage yaw rate limit according to the greater in magnitude of the first stage yaw rate limit and a previous value of said second stage yaw rate limit; and

limiting the desired yaw rate according to the lesser in magnitude of the second stage yaw rate limit and the desired yaw rate.

6. The improvement of claim 5, wherein the peak excursion of the first stage yaw rate limit is identified by detecting a reduction in magnitude of said first stage yaw rate limit within an envelope defined by the desired yaw rate.

7. The improvement of claim 5, including the steps of:

preserving the polarity of the measured lateral acceleration in developing said preliminary yaw rate limit; and

filtering said preliminary yaw rate limit so that said preliminary yaw rate limit has a frequency response similar to a frequency response of said desired yaw rate.

8. The improvement of claim 5, including the step of:

setting said first and second stage yaw rate limits equal to said desired yaw rate when said yaw rate control is deactivated.