System and method for locomotive adhesion control

1. A traction control system for controlling an electric traction motor drivingly coupled to a wheel of a tractive vehicle, comprising:

means for determining speed of the wheel;

means for determining tractive effort of the wheel; and

control circuitry for controlling drive signals to the motor based upon the wheel speed and tractive effort.

2. The system of claim 1 , wherein the means for determining tractive effort includes an estimator coupled to a motor speed sensor and to a motor torque sensor and configured to estimate a tractive effort value or wheel speed value or a torsional vibration value based upon the speed, the torque, or a combination thereof.

3. The system of claim 2 , wherein the means for determining torsional vibration includes signals representing wheel speeds or wheel tractive efforts or motor torque or torsional torque or motor speed or wheel strain or axle strain or dog-bone strain, or a combination thereof.

4. The system of claim 1 , wherein the vehicle is a locomotive.

5. The system of claim 1 , further comprising means for determining torsional vibration of an axle-wheel system in which the wheel is included, and wherein the control circuitry controls the drive signals based also upon the torsional vibration.

6. The system of claim 1 , wherein the means for determining the speed of the wheel includes a speed sensor for sensing a speed parameter representative of speed of the wheel.

7. The system of claim 1 , wherein the means for determining tractive effort includes a tractive effort sensor for sensing a parameter representative of torque tractive effort of the wheel.

8. The system of claim 7 , wherein the tractive effort sensor is a strain sensor.

9. The system of claim 1 , wherein the control circuitry is configured to determine current conditions with respect to optimum creep based upon wheel speed and tractive effort, and to control the drive signals based thereon.

10. The system of claim 1 , wherein the control circuitry is configured to regulate creep based upon a comparison of estimated or measured wheel speed with estimated or measured vehicle speed.

11. The system of claim 1 , wherein the means for determining tractive effort determines tractive effort based at least in part upon a direction of application of the tractive effort.

12. The system of claim 1 , wherein the means for determining speed and the means for determining tractive effort account for position of the motor and a suspension system between the motor and the vehicle.

13. A traction control system for controlling an electric traction motor drivingly coupled to an axle-wheel set including two wheels joined by an axle oVa tractive vehicle, comprising:

means for determining speed of each wheel;

means for determining tractive effort of each wheel; and

control circuitry for controlling drive signals to the motor based upon the wheel speeds and tractive efforts;

wherein the means for determining tractive effort includes an estimator coupled to a motor speed sensor and to a motor torque sensor and configured to estimate a tractive effort value or wheel speed value or a torsional vibration value based upon the speed, the torque, or a combination thereof.

14. A traction control system for controlling a plurality of electric traction motors drivingly coupled to wheels of a tractive vehicle, comprising:

means for determining speed of each wheel;

means for determining tractive effort of each wheel; and

control circuitry for controlling drive signals to the motors based upon the wheel speeds and tractive efforts.

15. The system of claim 14 , wherein the means for determining tractive effort includes an estimator coupled to motor speed sensors and to motor torque sensors and configured to estimate a tractive effort value or a wheel speed value or a torsional vibration value based upon the speed, the torque, or a combination thereof.

16. The system of claim 15 , wherein the control circuitry controls the drive signals to the motors based upon interaction between or among the wheels to maximize overall tractive effort.

17. The system of claim 16 , wherein the interaction is between or among multiple trucks.

18. The system of claim 16 , wherein the interaction is within a truck.

19. The system of claim 14 , wherein the control circuitry applied the control signals to the motors to cause a different level of creep for different wheels or axle-wheel sets.

20. The system of claim 14 , wherein the means for determining the speed of the wheels includes speed sensors for sensing a speed parameter representative of speed of each wheel.

21. The system of claim 14 , wherein the means for determining tractive effort includes tractive effort sensors for sensing a parameter representative of tractive effort of each wheel.

22. A method for controlling a traction motor of a propulsion system of a tractive vehicle, comprising:

determining speed of the wheel;

determining tractive effort of the wheel; and

applying drive signals to the motor based upon the wheel speed and tractive effort.

23. The method of claim 22 , further comprising determining torsional vibration of an axle-wheel system in which the wheel is included, and wherein the drive signals are applied based also upon the torsional vibration.

24. The method of claim 22 , wherein the speed of the wheel is determined based upon a sensed signal from a speed sensor that senses a parameter representative of speed of the wheel.

25. The method of claim 22 , wherein the tractive effort is determined based upon a sensed signal from a tractive effort sensor that senses a parameter representative of tractive effort of the wheel.

26. The method of claim 22 , wherein the tractive effort is determined by an estimator coupled to a motor speed sensor and to a motor torque sensor and configured to estimate a tractive effort value or a creep value or a wheel speed value based upon the speed, the torque, or a combination thereof.

27. A method for controlling a plurality of electric traction motors drivingly coupled to wheels of a tractive vehicle, comprising:

determining speed of each wheel;

determining tractive effort of each wheel; and

applying drive signals to each motor based upon the wheel speed and tractive effort.

28. The system of claim 27 , wherein the control signals applied to the motors cause a different level of creep for different wheels or axle-wheel sets.

29. A traction control system for controlling an electric traction motor drivingly coupled to a wheel of a tractive vehicle, comprising:

a machine readable medium; and

code stored on the machine readable medium including instructions for determining speed of the wheel, for determining tractive effort of the wheel, and for controlling drive signals to the motor based upon the wheel speed and tractive effort.

30. A traction control system for controlling a plurality of electric traction motors drivingly coupled to wheels of a tractive vehicle, comprising:

a machine readable medium; and

code stored on the machine readable medium including instructions for determining speed of each wheel, for determining tractive effort of each wheel, and for controlling drive signals to the motors based upon the wheel speeds and tractive efforts.