Load transfer adaptive traction control system

• US 7,873,459 B2
• Filed: 07/29/2005
• Issued: 01/18/2011
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Fodor, Michael, Hrovat, Davor
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Amin; Bhavesh V
• Application Number:
  US11/161,325
• Publication Number:
  US 20070027605A1
• Time in Patent Office: 1,999 Days
• Field of Search: 701/36, 701/45, 701/53, 701/54, 701/58, 701/59, 701/71, 701/75, 701/79, 701 82- 86, 701/90, 701/124
• US Class Current: 701/74
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/12 including control of differentials
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 2040/1307 Load distribution on each wheel suspension
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/18 Roll
• CPC Class Codes: B60W 2710/06 Combustion engines, Gas turbines
• CPC Class Codes: B60W 2720/30 Wheel torque
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 30/18172 Preventing, or responsive to skidding of wheels

Abstract

A method of controlling a vehicle that includes determining a dynamic normal load for the vehicle wheel, modifying the requested torque signal from a traction control system in response to the dynamic normal load to form a modified requested torque and controlling the engine in response to the modified requested torque. The controlling may be performed using the ratio of the dynamic normal load and the steady state normal load to form the modified requested torque.

Claims

1. A method for controlling a vehicle with a traction control system that accounts for load transfers during vehicle operation, the method comprising:

controlling a drive wheel of the vehicle according to a modified power train torque request, the power train torque request being modified in response to torque transfer on an inside driven wheel of the vehicle and based on a lateral acceleration of the vehicle, a longitudinal acceleration of the vehicle, a yaw rate of the vehicle, and a difference between undriven wheel speeds of the vehicle.

2. The method of claim 1, further comprising sensing and estimating the yaw rate of the vehicle.

3. The method of claim 1, further comprising estimating a road surface coefficient of friction based on the dynamic normal load and the modified power train torque request.

4. The method of claim 1, further comprising inputting the modified power train torque request to a wheel torque management system of the vehicle via powertrain torque control.

5. The method of claim 1, further comprising inputting the modified power train torque request to a wheel torque management system of the vehicle via brake torque control.

6. The method of claim 1, wherein the load transfer is side-to-side.

7. The method of claim 1, wherein the load transfer is front-to-rear.

8. The method of claim 1, further comprising estimating dynamic normal load of the drive wheel of a front-wheel-drive vehicle with the following equation

9. The method of claim 1, further comprising estimating dynamic normal load of the drive wheel of a rear-wheel-drive vehicle with the following equation

10. A method for controlling a vehicle with a traction control system that accounts for load transfers during vehicle operation on a road surface, the method comprising:

inputting constants representing gravity, a distance from a front axle to a center- of-gravity of the vehicle, a distance from a rear axle to a center-of-gravity of the vehicle, a mass of the vehicle, a height of the center-of-gravity of the vehicle, and a track width of the vehicle;

inputting signals from sensors including a yaw rate sensor, a lateral acceleration sensor, and a longitudinal acceleration sensor;

calculating a static normal load force of the inside driven wheel;

calculating a ratio of a steady state cornering normal force of the inside driven wheel to the static normal load force of the inside driven wheel;

calculating a ratio factor representing a ratio of a previous ratio of the steady state cornering normal force of the inside driven wheel to the static normal load force of the inside driven wheel to a current ratio of the steady state cornering normal force of the inside driven wheel to the static normal load force of the inside driven wheel;

modifying a requested torque to reflect the change in the ratio of the steady state cornering normal force of the inside driven wheel to the static normal load force of the inside driven wheel; and

controlling one or more of an engine of the vehicle and brakes of the vehicle according to the modified requested torque.

11. The method of claim 10, wherein the static normal load for the inside driven wheel in a front-wheel-drive vehicle is calculated with the following equation

12. The method of claim 10, wherein the static normal load for the inside driven wheel in a rear-wheel-drive vehicle is calculated with the following equation

13. The method of claim 11, wherein the ratio of the steady state cornering normal force of the inside driven wheel to the static normal load force of the inside driven wheel is calculated with the following equation

14. The method of claim 12, wherein the ratio of the steady state cornering normal force of the inside driven wheel to the static normal load force of the inside driven wheel is calculated with the following equation

15. The method of claim 13, wherein the lateral force on the vehicle is calculated with the following equation

16. The method of claim 14, wherein the lateral force on the vehicle is calculated with the following equation

17. The method of claim 16, wherein the yaw acceleration is estimated with the following equation

18. The method of claim 10, further comprising sensing and estimating the yaw rate of the vehicle.

19. The method of claim 10, further comprising estimating a road surface coefficient of friction based on the steady state cornering normal force of the inside driven wheel and the modified torque request.