System to measure wheel liftoff

• US 20060190143A1
• Filed: 02/22/2005
• Published: 08/24/2006
• Est. Priority Date: 02/22/2005
• Status: Active Grant

• Current Assignee: Continental Automotive Systems, Inc. (Continental AG)
• Original Assignee: Continental Teves Incorporated (Continental AG)
• Inventors: Bauer, Geoffrey Burke
• Granted Patent: US 7,557,697 B2
• Time in Patent Office: Days
• US Class Current: 701/1
• CPC Class Codes: B60T 2240/06 Wheel load; Wheel lift
• 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

Abstract

The present invention is directed to a system for determining lift-off or wheel departure of one or more wheels associated with a vehicle from a road. The system includes a sensor that measures the wheel speed of at least one wheel, and a controller that calculates the resonance frequency of the at least one wheel, calculates variations in the resonance frequency, compares the variations with a threshold, and indicates lift-off of the wheel from the road if the variations exceed a threshold.

Claims

1. A method of determining wheel departure from a road comprising:

measuring the wheel speed of at least one wheel;

calculating the resonance frequency of the at least one wheel;

calculating variations in the resonance frequency;

comparing the variations with a threshold; and

indicating lift-off of the wheel from the road if the variations exceed a threshold.

2. The method of claim 1 wherein the measuring provides a signal that is subsequently filtered in a filter.

3. The method of claim 2 wherein the filter employs a second order spring-mass-damper model of the wheel to generate parameters of interest.

4. The method of claim 3 wherein the parameters of interest are input data to calculate the resonance frequency.

5. The method of claim 2 wherein the filter is an RLS filter.

6. The method of claim 2 wherein the filter is a Kalman filter.

7. The method of claim 2 wherein the signal is transmitted to a pre-filter before the filter to remove noise and unwanted information.

8. A system for determining wheel departure from a road comprising:

a sensor that measures the wheel speed of at least one wheel; and

a controller that calculates the resonance frequency of the at least one wheel, calculates variations in the resonance frequency, compares the variations with a threshold, and indicates lift-off of the wheel from the road if the variations exceed a threshold.

9. The system of claim 8 further comprising a filter that filters a signal associated from with the wheel speed from the sensor

10. The system of claim 9 wherein the filter employs a second order spring-mass-damper model of the wheel to generate parameters of interest.

11. The system of claim 10 wherein the parameters of interest are input data to calculate the resonance frequency.

12. The system of claim 9 wherein the filter is an RLS filter.

13. The system of claim 9 wherein the filter is a Kalman filter.

14. The system of claim 9 further comprising a pre-filter wherein the signal is transmitted to a pre-filter to remove noise and unwanted information.