Controlling a digging operation of an industrial machine

1. A method of controlling a digging operation of an industrial machine, the industrial machine including a dipper handle, a dipper, and a crowd motor drive, the method comprising:

determining an angle of the dipper handle;

comparing the angle of the dipper handle to one or more dipper handle angle limits;

determining an acceleration associated with the dipper;

determining a crowd retract factor based on the acceleration;

comparing the crowd retract factor to a threshold crowd retract factor; and

setting a crowd speed reference for the crowd motor drive based on the comparison of the angle of the dipper handle to one or more dipper handle angle limits and the comparison of the crowd retract factor to the threshold crowd retract factor.

2. The method of claim 1 , wherein the acceleration associated with the dipper is a negative acceleration.

3. The method of claim 1 , wherein the one or more dipper handle angle limits are between approximately zero degrees and approximately ninety degrees with respect to a horizontal position of the dipper handle.

4. The method of claim 1 , further comprising setting a crowd retract torque for the crowd motor drive based on the comparison of the angle of the dipper handle to one or more dipper handle angle limits and the comparison of the crowd retract factor to the threshold crowd retract factor.

5. The method of claim 4 , wherein the crowd retract torque is set to a value greater than an standard operational value for crowd retract torque.

6. The method of claim 5 , wherein the value is set to a value of less than approximately 400% of the standard operational value for crowd retract torque.

7. The method of claim 1 , further comprising

determining a crowd motor torque; and

comparing the crowd torque to one or more crowd motor torque limits.

8. The method of claim 7 , wherein setting the crowd retract torque is further based on the comparison of the crowd torque to the one or more crowd motor torque limits.

9. An industrial machine comprising:

a dipper handle connected to a dipper;

a crowd motor drive configured to provide one or more control signals to a crowd motor, the crowd motor operable to provide a force to the dipper handle to move the dipper handle toward or away from a bank; and

a controller connected to the crowd motor drive, the controller configured to

determine an acceleration associated with the dipper,

determine a crowd retract factor based on the acceleration,

compare the crowd retract factor to a threshold crowd retract factor, and

set a crowd speed reference for the crowd motor drive based on the comparison of the retract factor to the threshold retract factor.

10. The industrial machine of claim 9 , wherein the acceleration associated with the dipper is a negative acceleration.

11. The industrial machine of claim 9 , wherein the one or more dipper handle angle limits are between approximately zero degrees and approximately ninety degrees with respect to a horizontal position of the dipper handle.

12. The industrial machine of claim 9 , wherein the controller is further configured to set a crowd retract torque for the crowd motor drive based on the comparison of the retract factor to the threshold retract factor.

13. The industrial machine of claim 9 , wherein the crowd retract torque is set to a value greater than a standard operational value for crowd retract torque.

14. The industrial machine of claim 13 , wherein the value is set to a value of less than approximately 400% of the standard operational value for crowd retract torque.

15. The industrial machine of claim 13 , wherein the value is set to approximately 150% of the standard operational value for crowd retract torque.

16. A method of controlling a digging operation of an industrial machine, the industrial machine including a dipper and a crowd drive, the method comprising:

determining an acceleration associated with the industrial machine;

determining a crowd retract factor based on the acceleration;

comparing the crowd retract factor to a threshold crowd retract factor; and

setting a crowd speed reference for the crowd drive based on the comparison of the crowd retract factor to the threshold crowd retract factor.

17. The method of claim 16 , wherein the acceleration is a negative acceleration.

18. The method of claim 16 , wherein the threshold crowd retract factor is a threshold acceleration, and the crowd retract factor is a value for the acceleration associated with the industrial machine.

19. The method of claim 16 , further comprising setting a crowd retract torque for the crowd drive based on the comparison of the crowd retract factor to the threshold crowd retract factor.

20. The method of claim 19 , wherein the crowd retract torque is set to a value greater than a standard operational value for crowd retract torque.

21. The method of claim 20 , wherein the value is set to a value of approximately 150% of the standard operational value for crowd retract torque.

22. The method of claim 16 , wherein the crowd retract torque is operably set to dissipate kinetic energy of a crowd motor and crowd transmission.

23. The method of claim 16 , wherein the industrial machine is a rope shovel.