Method and system for independently electronically controlling steering of vehicle wheels

• US 6,554,094 B1
• Filed: 12/17/1999
• Issued: 04/29/2003
• Est. Priority Date: 12/17/1999
• Status: Expired due to Term

• Current Assignee: Meritor Heavy Vehicle Systems, LLC (Meritor, Inc. (Nevada))
• Original Assignee: Meritor Heavy Vehicle Systems, LLC (Meritor, Inc. (Nevada))
• Inventors: Keeney, Christopher S., Molde, Dean A., Montgomery, Gerald J., Bell, Dale, Palmeri, Frank A., Kyrtsos, Christos T.
• Primary Examiner(s): BOEHLER, ANNE MARIE M
• Application Number:
  US09/466,297
• Time in Patent Office: 1,229 Days
• Field of Search: 180/402, 180/403, 180/411, 180/428, 180/432, 180/433, 180/435, 180/438, 180/422, 180/423, 180/444, 152/416, 152/417
• US Class Current: 180/402
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B62D 5/001 Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup
• CPC Class Codes: B62D 5/0418 Electric motor acting on road wheel carriers
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence

Abstract

A method and system for independently controlling the steering of at least two wheels of a vehicle includes a steering angle sensor for sensing a desired amount of turning of the vehicle and a direction for the desired amount of turning. An electronic control unit, in communication with the steering angle sensor, determines a first desired turning angle for one of the wheels and a second desired turning angle for the other one of the wheels based on the desired amount of turning of the vehicle and the direction of the turning of the vehicle. The second desired turning angle may be the same as or different from the first desired turning angle. Independent turning mechanisms are coupled to each of the wheels and receives control signals from the electronic control unit for controlling the turning angles of each of the wheels independently of the other wheel.

Claims

1. A method for independently controlling the steering of at least two wheels of a vehicle, the method comprising:

sensing a desired amount of turning of the vehicle;

determining a direction for the desired amount of turning;

determining a first desired turning angle for one of the wheels and a second desired turning angle for the other one of the wheels based on the desired amount of turning of the vehicle and the direction of the turning of the vehicle, the second desired turning angle being one of the same as and different from the first desired turning angle;

controlling each of the wheels based on the first and second desired turning angles;

sensing a pressure in each of the wheels wherein each of the wheels include a valve stem attached thereto each having a one-way check valve disposed therein for allowing air to flow into the wheel; and

controlling an amount of air flow into each of the wheels based on a comparison of the pressure in each of the wheels.

2. The method as recited in claim 1 further comprising:

sensing a predetermined condition;

sensing a speed of each of the wheels over a first predetermined distance upon sensing the predetermined condition; and

controlling a distance between a portion of each of the wheels based on the speed of each of the wheels.

3. The method as recited in claim 2 wherein sensing the first predetermined condition comprises:

sensing the pressure in each of the wheels;

sensing a speed of each of the wheels over a second predetermined distance; and

determining there is no difference in tire pressure and wheel speed between each of the wheels.

4. The method as recited in claim 2 wherein controlling the distance between each of the wheels includes comparing the speed of each wheel to determine if there is a difference in speed between each of the wheels.

5. The method as recited in claim 2 wherein the vehicle includes a rack and pinion steering system having a rack and pinion for controlling the turning of the wheels and wherein controlling the distance between the portions of the wheels includes controlling a position of the rack relative to the pinion.

6. The method as recited in claim 2 wherein the vehicle includes a worm-gear steering system having a lead screw for controlling the turning of the wheels and wherein controlling the distance between the wheels includes controlling a position of the lead screw.

8. The method as recited in claim 1 wherein the vehicle includes a rotatable steering wheel for receiving input from a driver of the vehicle indicative of the amount and direction of turning of the vehicle desired by the driver and wherein sensing the desired amount of turning of the vehicle comprises sensing an angle of rotation of the steering wheel.

7. The method as recited in 2 further comprising:

sensing a speed of the vehicle; and

wherein controlling the distance between the portions of the wheels includes controlling the distance between the wheels based on the speed of the vehicle and the speed of each of the wheels.

9. A system for independently controlling the steering of at least two wheels of a vehicle having a steering wheel for enabling a driver to turn the vehicle, the system comprising:

a steering angle sensor for sensing a desired amount of turning of the vehicle;

an electronic control unit coupled to the steering angle sensor;

a first turning mechanism coupled to one of the wheels and the electronic control unit for turning the one of the wheels;

a second turning mechanism coupled to the other one of the wheels and the electronic control unit for turning the other one of the wheels;

wherein the electronic control unit is operative to determine a direction for the desired amount of turning, determine a first desired turning angle for one of the wheels and a second desired turning angle for the other one of the wheels based on the desired amount of turning of the vehicle and the direction of the turning of the vehicle, the second desired turning angle being one of the same as and different from the first desired turning angle, and control the first and second turning mechanisms based on the first and second desired turning angles, respectively, in order to independently control the turning of each of the wheels;

a first and second valve stem attached to each of the wheels and each leaving a one-way check valve disposed therein for allowing air to flow into the wheels;

a first and second pressure sensor disposed in each of the wheels for sensing a pressure in each of the wheels; and

wherein the electronic control unit is further operative to control the first and second valve stems based on a comparison of the pressure sensed in each of the wheels in order to control the flow of air into each of the wheels.

10. The system as recited in claim 9 further comprising:

a first and second wheel speed sensor for sensing a speed of each of the wheels and generating first and second wheel speed signals for receipt by the electronic control unit; and

wherein the electronic control unit is further operative to sense a predetermined condition, receive the first and second wheel speed signals over a first predetermined amount of time upon sensing the predetermined condition, and control the first and second turning mechanisms based on the first and second speed signals received over the predetermined amount of time in order to control a distance between a portion of each of the wheels.

11. The system as recited in claim 10 wherein the electronic control unit, in sensing the predetermined condition, is further operative to determine a rolling radius of each of the wheels based on the speed of each of the wheels over a second predetermined distance, determine if the pressures between each of the wheels is the same and determine if the rolling radius of each of the wheels is the same.

12. The system as recited in claim 10 wherein the first and second turning mechanisms are rack and pinion steering systems each having a rack and pinion for controlling the turning of the wheels and wherein the electronic control unit, in controlling the distance between the wheels, is further operative to control a position of the rack relative to the pinion.

13. The system as recited in claim 10 wherein the first and second turning mechanisms are worm-gear steering systems each having a lead screw for controlling the turning of the wheels and wherein the electronic control unit, in controlling the distance between the wheels, is further operative to control a position of the lead screw.

14. The system as recited in 10 further comprising:

a vehicle speed sensor for sensing a speed of the vehicle; and

wherein the electronic control unit, in controlling the distance between the wheels, is further operative to control the distance between the portions of the wheels based on the speed of the vehicle and the speed of each of the wheels.