Estimation of vehicle speed in all-wheel-drive vehicle

Patent metadata

Field	Value
Publication number	US-11584352-B2
Application number	US-201816155282-A
Country	US
Kind code	B2
Filing date	Oct 9, 2018
Priority date	Oct 9, 2018
Publication date	Feb 21, 2023
Grant date	Feb 21, 2023

Abstract

A vehicle includes an electric machine and a controller. The controller is programmed to responsive to a threshold difference, indicative of wheel slip, between average wheel speed and a vehicle speed that is based on a difference between wheel acceleration and measured vehicle acceleration, command a speed to the electric machine to reduce the wheel slip.

First claim

What is claimed is:

1. A vehicle comprising:
an electric machine; and
a controller programmed to:
receive a driver-demanded torque,
responsive to an average wheel speed exceeding a threshold that is based on a vehicle speed and is indicative of wheel slip, command a speed-control torque to the electric machine based on an error between a target speed, derived from the vehicle speed, and a measure speed of the electric machine to reduce the wheel slip, wherein the vehicle speed is based on a difference between wheel acceleration and measured vehicle acceleration, and
command a torque to the electric machine based on the driver-demanded torque when the average wheel speed is less than the threshold.

2. The vehicle of claim 1 further comprising primary and secondary axles, wherein the electric machine powers one of the primary and secondary axles.

3. The vehicle of claim 2 further comprising a second electric machine that powers the other of the primary and secondary axles.

4. The vehicle of claim 3 , wherein the controller is further programmed to:
responsive to an average wheel speed of the other of the primary and secondary axles exceeding the threshold, command a speed-control torque to the second electric machine based on an error between a target speed, derived from the vehicle speed, and a measure speed of the second electric machine to reduce the wheel slip of the other of the primary and secondary axles.

5. The vehicle of claim 1 , wherein the vehicle speed is further based on wheel measured speed.

6. The vehicle of claim 1 , wherein the vehicle speed is further based on a grade offset acceleration.

7. The vehicle of claim 6 , wherein the grade offset acceleration is based on a derivative of a measured speed of a slowest wheel.

8. The vehicle of claim 1 further comprising speed sensors each associated with one of the wheels and configured to output a signal indicative of wheel speed.

9. The vehicle of claim 1 further comprising an internal combustion engine configured to power wheels.

10. A method of controlling a vehicle comprising:
commanding torque to an electric machine based on a driver-demanded torque; and
when a speed difference between average wheel speed and a vehicle speed exceeds a threshold indicative of wheel slip, commanding a speed-control torque to the electric machine such that a product of the average wheel speed and wheel rolling radius converges toward the vehicle speed to reduce the wheel slip, wherein the vehicle speed is based on a difference between wheel acceleration and measured vehicle acceleration.

11. The method of claim 10 , wherein the vehicle speed is further based on a grade offset acceleration.

12. The method of claim 11 , wherein the grade offset acceleration is based on a derivative of a measured speed of a slowest wheel.

13. The method of claim 10 , wherein the vehicle speed is further based on measured wheel speed.

14. The vehicle of claim 1 , wherein the target speed is based on a quotient of the vehicle speed and an effective rolling radius of a wheel.

15. The vehicle of claim 1 , wherein the target speed is equal to a quotient of the vehicle speed and an effective rolling radius of a wheel multiplied by a speed ratio between the electric machine and the wheel.

16. A vehicle comprising:
an electric machine; and
a controller programmed to:
command torque to the electric machine based on a driver-demanded torque; and
when a speed difference between average wheel speed and a vehicle speed exceeds a threshold indicative of wheel slip, command a speed-control torque to the electric machine such that a product of the average wheel speed and wheel rolling radius converges toward the vehicle speed to reduce the wheel slip, wherein the vehicle speed is based on a difference between wheel acceleration and measured vehicle acceleration.

Assignees

• Ford Global Tech Llc

Inventors

• Velazquez Alcantar Jose
• Torres Joseph Jay
• Barrette Peter James
• Bruns Richard David
• Stout Corwin
• Johri Rajit

Classifications

• Y02T10/72

  Electric energy management in electromobility · CPC title

• B60L2240/465

  Slip · CPC title

• B60W2510/081

  Speed · CPC title

• B60W2520/105

  Longitudinal acceleration · CPC title

• B60L2240/423

  Torque · CPC title