Control system for active attenuation of torque-steer via electric power steering

• US 20040167694A1
• Filed: 02/26/2003
• Published: 08/26/2004
• Est. Priority Date: 02/26/2003
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Tamai, Goro
• Granted Patent: US 7,272,478 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• CPC Class Codes: B62D 5/0472 for damping vibrations

Abstract

The present invention provides a device for dynamically counteracting torque steer which includes a processor adapted to calculate a correction factor from a calculated axle torque on front wheel drive half shafts of the vehicle. A power circuit is provided responsive to the calculated correction factor to provide an offset current through the power steering unit or the braking system of the vehicle to counteract the torque steer.

Claims

1. A device for countering torque steer of a vehicle, the device comprising:

a control unit operationally engaged with a steering system on the vehicle to offset a torque steer applied to the steering system; and

a processor responsive to at least one parameter read from at least one vehicle sensor to determine a correction factor based on the at least one parameter, the correction factor representative of an adjustment required by the control unit to offset the torque steer applied to the steering system;

wherein the control unit is responsive to a correction signal output from the processor to cause the control unit to counter the torque steer of the vehicle, wherein the correction signal is based on the correction factor.

2. The device according to claim 1, further comprising:

a transaxle;

a set of wheels;

a set of shafts operationally engaged with the set of wheels and the transaxle to supply rotational energy from the transaxle to the set of wheels, wherein the processor is adapted to;

calculate an axle torque on the set of shafts responsive to the at least one parameter; and

determine the correction factor from the calculated axle torque.

3. The device according to claim 2, wherein the processor includes a look-up table, wherein the processor is adapted to select the correction factor from the look-up table based on the calculated axle torque.

4. The device according to claim 2, wherein the at least one parameter includes a manifold pressure, a current gear of the transaxle, and an axle speed of the set of shafts.

5. The device according to claim 1, wherein the control unit is a power steering unit.

6. The device according to claim 1, wherein the control unit is a differential braking system.

7. A vehicle comprising:

a power plant;

a pair of wheels;

a transaxle receiving rotational energy from the power plant;

a pair of shafts, each of the pair of shafts extending from the transaxle to a respective one of the pair of wheels;

a steering system for turning the pair of wheels to cause turning of the vehicle;

a torque steer countering device including;

a processor responsive to at least one parameter supplied from at least one vehicle sensor to determine a correction factor based on the at least one parameter; and

a control unit responsive to a correction signal output from the processor to counter a torque steer of the steering system, wherein the correction signal is based on the correction factor.

8. The vehicle according to claim 7, where in the processor is adapted to:

calculate an axle torque on the pair of shafts in response to the at least one parameter; and

determine the correction factor from the calculated axle torque.

9. The vehicle according to claim 8, wherein the processor includes a look-up table, wherein the processor is adapted to select the correction factor from the look-up table based on the calculated axle torque.

10. The vehicle according to claim 8, wherein:

the at least one parameter includes a manifold pressure, a current gear of the transaxle, and an axle speed of the pair of shafts.

11. The vehicle according to claim 7, wherein the control unit is a power steering unit.

12. The vehicle according to claim 7, wherein the control unit is a differential braking system.

13. A device for countering torque steer comprising:

a control unit engaged to a steering system to counter the torque steer; and

a processor including a look-up table, the processor responsive to a manifold pressure, a current gear of a transaxle, and an axle speed of a pair of half shafts of the vehicle to calculate an axle torque on a pair of half shafts, the processor adapted to determine a correction factor based on the calculated axle torque on the pair of half shafts;

wherein the control unit counteracts torque steer based on a signal from the processor representative of the correction factor.

14. A method for counteracting torque steer of a vehicle, the method comprising the steps of:

reading at least one engine parameter from at least one sensor in the vehicle;

determining a correction factor based on the at least one engine parameter which is sufficient to counteract the torque steer; and

applying a correction torque to a steering system of the vehicle based on the determined correction factor, wherein the correction torque is sufficient to counteract the torque steer.

15. The method according to claim 14, further comprising a processor having a look-up table, the processor adapted to determine the correction factor from the look-up table.

16. The method according to claim 14, wherein the at least one engine parameter includes a manifold pressure, a current gear of a transaxle, and an axle speed.

17. The method according to claim 14, wherein the correction torque is applied by a differential braking system.

18. The method according to claim 14, wherein the correction torque is applied by a power steering unit.