Wheel lift identification for an automotive vehicle

• US RE40,268 E1
• Filed: 12/21/2004
• Issued: 04/29/2008
• Est. Priority Date: 09/25/2000
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Meyers, Joseph Carr, Brown, Todd Allen
• Primary Examiner(s): Nguyen; Tai
• Application Number:
  US11/019,148
• Time in Patent Office: 1,225 Days
• Field of Search: 340/440, 340/439, 340/441, 340/465, 340/438, 701/42, 701/45, 701/46, 701/70, 701/71
• US Class Current: 340/440
• CPC Class Codes: B60G 2400/208 of wheel rotation
• CPC Class Codes: B60G 2400/32 Torque on propulsion shaft
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60G 2800/70 Estimating or calculating vehicle parameters or state variables
• CPC Class Codes: B60G 2800/9124 Roll-over protection systems, e.g. for warning or control
• CPC Class Codes: B60G 2800/952 Electronic driving torque distribution
• CPC Class Codes: B60R 16/0233 Vehicle tilting, overturning or roll over
• CPC Class Codes: B60T 2230/03 Overturn, rollover
• CPC Class Codes: B60T 2240/06 Wheel load; Wheel lift
• CPC Class Codes: B60T 8/17551 determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters

Abstract

A system for detecting wheel lift of an automotive vehicle has a speed sensor (22) coupled to a wheel (12) of automotive vehicle (10). A torque control system (20) is coupled to wheel (12) to change the torque at the wheel. A controller (18) is coupled to the torque control system and a speed sensor. The controller (18) determines lift by changing the torque of the wheel, measuring the change in torque and indicating lift in response to change in torque which may be indicated by wheel speed.

Claims

1. A method for determining wheel lift of a wheel of an automotive vehicle comprising the steps of:

applying a change of torque to the wheel;

measuring a change in a wheel condition since initiating the step of applying a change of torque;

indicating wheel lift if the change in the wheel condition is greater than a predetermined value.

2. A method as recited in claim 1 wherein the condition is one selected from the group of acceleration and speed.

3. A method as recited in claim 1 further comprising the step of removing the change of torque;

measuring a wheel condition after the step of removing the change of torque.

4. A method as recited in claim 3 further comprising the step of determining whether the second wheel condition is above a threshold.

5. A method as recited in claim 1 wherein the step of applying a change of torque comprises applying a brake to the wheel.

6. A method as recited in claim 5 further comprising the step of releasing the brake;

determining a wheel condition after the step of releasing the brake;

when the wheel condition does not increase over a reacceleration threshold, confirming wheel lift;

when wheel speed condition increases over a reacceleration threshold, indicating wheel contact.

7. A method as recited in claim 1 wherein the step of applying a change of torque comprises applying engine torque.

8. A method for monitoring a predetermined condition of an automotive vehicle having a plurality of wheels comprising the steps of:

determining a potential for the predetermined condition of the wheel;

measuring a first wheel speed of a suspected lifting wheel;

thereafter, changing the torque of a applied to the suspected lifting wheel from a first torque to a second torque;

changing the torque from the vehicle applied to the suspected lifting wheel from the second torque to the first torque;

measuring a second wheel speed of the suspected lifting wheel;

determining a wheel speed change as a function of the first wheel speed and the second wheel speed;

when the change in wheel speed is greater than a reacceleration threshold, confirming the wheel lift.

9. A method as recited in claim 8 wherein the predetermined condition is determining a potential for wheel lift comprises determining the potential for wheel lift as a function of roll angle, steering wheel angle, and road bank angle.

10. A method as recited in claim 8 wherein the step of changing the torque comprises the step of applying the brake.

11. A method as recited in claim 8 wherein the step of changing the torque comprises the step of applying engine torque.

12. A method as recited in claim 8 wherein a predetermined condition comprises a sensor failure.

13. A method as recited in claim 8 wherein the predetermined condition comprises wheel lift.

14. A method as recited in claim 8 further comprising the step of correcting lift by applying the brakes.

15. A method as recited in claim 8 further comprising the step of correcting lift by applying a steering correction.

16. A method as recited in claim 8 further comprising the step of calculating a traction level after the step of confirming wheel lift.

17. A system for detecting lift of a wheel of an automotive vehicle comprising:

a speed sensor coupled to the wheel producing a wheel speed signal;

a torque control system coupled to the wheel for changing the torque at applied to the wheel;

a controller coupled to the said torque control system and the wheel speed sensor, said controller determining lift by changing the torque of applied to the wheel, increasing the a brake torque until a maximum brake torque threshold is achieved, detecting a change in wheel speed since the application of the brake torque, comparing the change in wheel speed to a threshold, when the change in wheel speed is above the wheel speed change threshold value, indicating wheel lift, when the brake torque reaches a maximum value before the change in wheel speed reaches the threshold, holding the brake torque for a predetermined amount of time, continuing to monitor the change in wheel speed during a hold duration, determining a second change in wheel speed, comparing the second change in wheel speed to the threshold value, when the second chnage in wheel speed exceeds the threshold value during the hold duration, indicating lift.

18. A method for determining wheel lift of a vehicle comprising the steps of:

applying a torque to the a wheel by applying a brake torque;

increasing the brake torque to build until a maximum brake torque threshold is achieved;

detecting the a change in wheel speed since the application of brake torque;

comparing the change in wheel speed to a wheel speed change threshold;

when the change in speed is above the wheel speed change threshold value, indicating wheel lift;

when the brake torque reaches a maximum value before the change in wheel speed reaches the wheel speed change threshold, holding the torque for a predetermined amount of time;

continuing to monitor the change in wheel speed during a hold duration;

determining a second change in wheel speed;

comparing the second wheel speed to the threshold value;

when the second wheel speed exceeds the threshold value during the hold duration, indicating a wheel lift.

19. A method as recited in claim 18 further comprising the steps of:

releasing the torque;

determining a wheel speed change;

when the wheel speed change is greater than a reacceleration threshold, indicating wheel contact;

when the wheel speed change is less than the reacceleration threshold, confirming an indication of wheel lift.

20. A method as recited in claim 18 further comprising the step of calculating a traction level.

21. A method as recited in claim 18 further comprising the step of when wheel lift is detected, continually monitoring the wheel speed change for a sudden increase to acknowledge wheel contact.

22. A method for monitoring wheel lift of an automotive vehicle having a plurality of wheels comprising the steps of:

determining a potential for wheel lift of the wheel as a function of road bank angle;

measuring a first wheel speed of a suspected lifting wheel;

thereafter, changing a torque of the suspected lifting wheel from a first torque to a second torque;

changing the torque of the suspected lifting wheel from the second torque to the first torque;

measuring a second wheel speed of the suspected lifting wheel;

determining a wheel speed change as a function of the first wheel speed and the second wheel speed;

when the change in wheel speed is greater than a reacceleration threshold, confirming wheel lift.

23. A method for monitoring a sensor failure condition of an automotive vehicle having a plurality of wheels comprising the steps of:

determining a potential for sensor failure;

measuring a first wheel speed;

thereafter, changing a torque of a suspected lifting wheel from a first torque to a second torque;

changing the torque from the second torque to the first torque;

measuring a second wheel speed;

determining a wheel speed change as a function of the first wheel speed and the second wheel speed;

when the change in wheel speed is greater than a reacceleration threshold, confirming the sensor failure.