Steering actuated wheel lift identification for an automotive vehicle

• US 6,397,127 B1
• Filed: 09/25/2000
• Issued: 05/28/2002
• 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): Cuchlinski, Jr., William A.
• Assistant Examiner(s): To, Tuan C
• Application Number:
  US09/669,512
• Time in Patent Office: 610 Days
• Field of Search: 701/1,38,72,78,83,45 303/146 340/440,438,461,462
• US Class Current: 701/1
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 17/0195 characterised by the regulation being combined with other vehicle control systems conjoint control of vehicle sub-units including control of suspension systems B60W10/22
• CPC Class Codes: B60G 21/08 characterised by use of gyroscopes gyroscopes for stabilising vehicle bodies without controlling suspension arrangements B62D37/06
• CPC Class Codes: B60G 2400/0521 Roll rate
• CPC Class Codes: B60G 2400/0523 Yaw rate
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/52 in tyre
• CPC Class Codes: B60G 2401/902 the sensor being an xy axis sensor
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60G 2800/0124 Roll-over conditions
• 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 2800/922 EBV - Electronic brake force distribution
• CPC Class Codes: B60G 2800/96 ASC - Assisted or power Steering control
• CPC Class Codes: B60T 2240/06 Wheel load; Wheel lift
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00
• CPC Class Codes: B60T 8/243 for roll-over protection
• CPC Class Codes: B60T 8/246 Change of direction
• 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

Abstract

A system for an automotive vehicle that includes a roll control system (16) and a wheel lift detector (20) is provided for an automotive vehicle (10). The automotive vehicle (10) has wheels (12) that when lifted from the road plane have less steering effort associated therewith. Preferably, each of the steered wheels (12) has a steering actuator (42) and an actuator sensor (30) for monitoring the steering effort. The load of the steering actuator (42) is monitored and the actuator (42) having the lightest load is determined. A steering perturbation is applied to the steering actuator and the steering effort is monitored during the perturbation. If the steering effort during the perturbation is lower than a lift threshold, then lift will be indicated. If the steering effort is greater than a lift threshold, then contact has been maintained with the road surface. In response to the indication of lift, corrective measures may be taken such as applying a counter steering effort or applying brakes in a predetermined fashion so as to counter the roll effect.

Claims

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

modifying a steering angle of the wheel from a first position to a second position;

monitoring an amount of steering effort during the step of modifying;

comparing the amount of steering effort to a lift threshold;

when the amount of steering effort is less than a lift threshold, indicating wheel lift.

2. A method as recited in claim 1 wherein said lift threshold is speed dependent.

3. A method as recited in claim 1 further comprising the step of returning the steering angle of the wheel to the second position after the step of monitoring.

4. A method as recited in claim 1 wherein said amount of steering effort is a function of actuator current.

5. A method as recited in claim 1 wherein said amount of steering effort is a function of hydraulic pressure.

6. A method as recited in claim 1 further comprising, after the step of indicating a wheel lift, applying a force to counter the wheel lift.

7. A method as recited in claim 1 wherein the step of modifying a steering angle comprises applying a steering perturbation having a predetermined amplitude for a predetermined time.

8. A method for controlling a rollover of an automotive vehicle having a plurality of wheels comprising the steps of:

determining a potential for wheel lift;

measuring the loads of the plurality of wheels;

identifying one of the plurality of wheels as a lightly loaded wheel;

applying a steering wheel angle change to the lightly loaded wheel;

monitoring a steering effort during the step of applying a steering wheel angle change;

when the steering effort of the lightly loaded wheel is less than a lift threshold, indicating wheel lift;

in response to indicating wheel lift, applying a force to counter rollover.

9. A method as recited in claim 8 wherein said force is a steering force.

10. A method as recited in claim 8 wherein said force is a brake force.

11. A method as recited in claim 8 wherein the step of applying a steering wheel angle changed comprises the step of increasing a path of rotation of the vehicle.

12. A method as recited in claim 8 wherein the potential for wheel lift is a function of vehicle velocity, steering wheel angle and actuator position.

13. A method as recited in claim 8 wherein the steering wheel angle change has a predetermined amplitude for a predetermined time.

14. A method as recited in claim 8 wherein effort is a function of actuator current.

15. A method as recited in claim 8 wherein said effort is a function of hydraulic pressure.

16. A method as recited in claim 8 wherein said lift threshold is speed dependent.

17. An automotive vehicle system comprising:

a first steering actuator;

an actuator sensor generating a steering effort signal corresponding to an amount of steering effort; and

,

a controller coupled to said steering actuator and said actuator sensor for modifying a steering angle of the wheel from a first position to a second position, monitoring said steering effort signal while modifying the steering angle, and when the effort signal is less than a lift threshold said controller indicating wheel lift.

18. A system as recited in claim 17 further comprising a second steering actuator and a second actuator sensor generating a second steering effort signal.

19. A system as recited in claim 18 wherein said controller is coupled to said second steering actuator and said second actuator position sensor, said controller measuring loads of the first steering actuator and the second steering actuator and identifying a lightly loaded wheel.

20. A system as recited in claim 17 further comprising a plurality of wheel lift determination sensors, said controller generating a confirmation signal in response to a failure of one of said plurality of wheel lift determination sensors.