Ackerman angle correction in a steering system for a low speed turn

• US 7,085,641 B2
• Filed: 11/01/2004
• Issued: 08/01/2006
• Est. Priority Date: 11/01/2004
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Post, James W. II
• Primary Examiner(s): Chin, Gary
• Application Number:
  US10/978,601
• Publication Number:
  US 20060095188A1
• Time in Patent Office: 638 Days
• Field of Search: 701/41, 701/42, 701/70, 180/443, 180/446
• US Class Current: 701/70
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60W 40/109 Lateral acceleration
• CPC Class Codes: B60W 40/11 Pitch movement
• CPC Class Codes: B60W 40/112 Roll movement
• CPC Class Codes: B60W 40/114 Yaw movement
• CPC Class Codes: B62D 6/00 Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence

Abstract

A method of calculating feed-forward lateral acceleration of a moving vehicle is provided. The method includes the use of a corrected steering angle of the vehicle. The steering angle is corrected by using the Ackerman steer angle of the vehicle. Depending upon the speed at which the vehicle is traveling the steering angle may be corrected using the full Ackerman steer angle, a fraction of the Ackerman steer angle or not at all.

Claims

1. A method of calculating a feed-forward lateral acceleration of a moving vehicle comprising the steps of:

measuring a speed of the moving vehicle;

measuring a steering angle of the moving vehicle;

calculating an Ackerman steer angle of the moving vehicle;

calculating a corrected steering angle of the moving vehicle using the Ackerman steer angle of the moving vehicle; and

calculating the feed-forward lateral acceleration of the moving vehicle using the measured speed of the moving vehicle and the corrected steering angle.

2. The method of claim 1, wherein the corrected steering angle is calculated by subtracting the Ackerman steer angle from the measured steering angle.

3. The method of claim 1, wherein the step of calculating the Ackerman steer angle includes measuring or calculating a yaw rate of the vehicle.

4. The method of claim 1, wherein the step of calculating the Ackerman steer angle includes measuring the speed of an outside vehicle wheel in a turn and measuring the speed of an inside vehicle wheel in the turn.

5. The method of claim 1, further including a step of calculating drive torque for each wheel of the vehicle on the basis of the calculated feed-forward lateral acceleration of the vehicle.

6. The method of claim 1, wherein the Ackerman steer angle is scaled as the speed of the moving vehicle increases.

7. The method of claim 1, wherein the vehicle speed is used to look up a lateral acceleration predictor using a predetermined table specific to the vehicle.

8. The method of claim 2 wherein the corrected steering angle is multiplied by an estimated lateral acceleration of the vehicle.

9. A system of calculating feed-forward lateral acceleration of a moving vehicle comprising:

means for measuring a speed of a moving vehicle;

means for measuring a steering angle of the moving vehicle;

means for calculating an Ackerman steer angle of the moving vehicle; and

means for calculating the feed-forward lateral acceleration of the moving vehicle using the measured speed of the moving vehicle and a steering angle corrected by using the Ackerman steer angle.