TIRE WINDUP COMPENSATION

• US 20150134201A1
• Filed: 11/08/2013
• Published: 05/14/2015
• Est. Priority Date: 11/08/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Lavoie, Erick Michael
• Granted Patent: US 9,434,415 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B62D 15/027 Parking aids, e.g. instruction means
• CPC Class Codes: B62D 9/00 Steering deflectable wheels not otherwise provided for steering positon indicators B62D15/02

Abstract

A system for measuring and compensating for tire windup occurring in road wheels during parking events. A controller receives data comprising a steering motor current and steering system component movement, from that data determines the amount of tire windup is present, and controls the motor to turn a road wheel to an initial position that allows the tire windup to turn the road wheel to a final position. The final desired position of the road wheel may be one for the desired location of the road wheel itself, for the steering wheel, or for a combination of the two. Final desired angular positions of the steering wheel may be one such that an ignition may have greater visibility or one such that the steering wheel is not locked under load.

Claims

1. A system for compensating for tire windup on a road wheel as a result of a parking event comprising:

a motor that produces a motor current when providing power steering;

a sensor capable of providing data relative to a steering component movement; and

a controller programmed to modify an output of the motor in response to the steering component movement data and motor current to reduce tire windup resulting from the parking event.

2. The system of claim 1 wherein the steering component is a steering wheel and the sensor measures steering wheel angular position.

3. The system of claim 1 wherein the controller is programmed to modify the output of the motor in response to the steering component movement data and motor current to achieve a predetermined desired road wheel angle position after tire windup is relieved.

4. The system of claim 3 wherein the controller energizes the motor to turn the road wheel past the predetermined desired road wheel angle position to allow the road wheel to spring-back into the predetermined desired road wheel angle position as tire windup is relieved.

5. The system of claim 3 wherein the controller reduces energy the motor before the road wheel reaches the predetermined desired road wheel angle position to allow the road wheel to spring-forward into the predetermined desired road wheel angle position as tire windup is relieved.

6. The system of claim 3 wherein the predetermined desired road wheel angle position is a direction other than straight forward on a vehicle.

7. The system of claim 1 further comprising a steering wheel, wherein the final steering wheel angular position may be effected by tire windup, and the controller is programmed to modify the output of the motor in response to the steering component movement data and motor current to achieve a predetermined desired steering wheel angle position as tire windup is relieved.

8. The system of claim 7 wherein the controller is programmed to energize the motor to turn the steering wheel past the predetermined desired steering wheel angle position to allow the road wheel to spring-back causing the steering wheel to rotate into the predetermined desired steering wheel angle position as tire windup is relieved.

9. The system of claim 7 wherein the controller is programmed to reduce energy to the motor before the steering wheel reaches the predetermined desired steering wheel angle position to allow the road wheel to spring-forward causing the steering wheel to rotate into the predetermined desired steering wheel angle position as tire windup is relieved.

10. The system of claim 7 wherein the predetermined desired steering wheel angle position is a position that allows the steering wheel to lock, and the tire windup is relieved such that the steering wheel locks without significant torque being placed on a steering wheel locking mechanism.

11. The system of claim 7 wherein the predetermined desired steering wheel angle position is a position that aligns an opening of the steering wheel with an ignition to provide greater visibility of the ignition.

12. The system of claim 1 wherein the parking event is an automatic computer controlled parking event.

13. A system for compensating for tire windup resulting from an automatic parking event comprising:

a controller capable of receiving a steering wheel angle position and programmed to determine an amount of tire windup based on a power steering motor current, and control a power steering motor to position a steering wheel at an overshoot/undershoot angular position to allow the steering wheel to rotate to a desired end-of-parking angular position as the tire windup is relieved.

14. The system of claim 13 wherein the controller corresponds the motor current to a friction and determines the amount of tire windup based off of the motor current and a tire windup factor.

15. The system of claim 14 wherein the tire windup factor is a tunable factor which may be input into the controller by a manufacturer, dealer, or driver.

16. The system of claim 14 wherein the tire windup factor is a tunable factor based on characteristics of the tire taken from a group consisting of material composition, ply construction, tread pattern, width, rim diameter, aspect ratio, rolling radius, recommended inflation pressure ranges, load rating, ground contact patch, and speed rating.

17. The system of claim 13 wherein the controller controls the power steering motor to turn a road wheel and the steering wheel past the desired end-of-parking steering wheel angle position to allow the road wheel to spring-back causing the steering wheel to rotate into the desired end-of-parking steering wheel angle position.

18. The system of claim 13 wherein the compensation for tire windup allows the steering wheel to be locked at the desired end-of-parking angular position with substantially no torque on a steering wheel locking mechanism.

19. The system of claim 13 wherein the desired end-of-parking angular position of the steering wheel is an angular position which allows for improved ignition locatability.

20. The system of claim 13 wherein the controller determines tire windup from a group consisting of, braking input, wheel speed sensor data, vehicle speed, gear position, throttle position, steering wheel torque, and longitudinal acceleration.