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 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 a hoist bail pull;

comparing the hoist bail pull to one or more hoist bail pull limits; and

setting a crowd torque limit for the crowd motor drive based on the comparison of the angle of the dipper handle to the one or more dipper handle angle limits and the comparison of the hoist bail pull to the one or more hoist bail pull limits,

wherein setting the crowd torque limit includes setting the crowd torque limit to a first crowd torque limit when the hoist bail pull is less than or approximately equal to a first of the one or more hoist bail pull limits, and setting the crowd torque limit to a second crowd torque limit when the hoist bail pull is greater than the first of the one or more hoist bail pull limits.

2. The method of claim 1 , wherein the crowd torque limit increases as the hoist bail pull increases.

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 , wherein setting the crowd torque limit includes setting the crowd torque limit to a first crowd torque limit when the hoist bail pull is less than or approximately equal to a first of the one or more hoist bail pull limits, and setting the crowd torque limit to a second crowd torque limit when the hoist bail pull is greater than the first of the one or more hoist bail pull limits.

5. The method of claim 1 , wherein the second crowd torque limit is greater than the first crowd torque limit.

6. The method of claim 1 , wherein the industrial machine is a rope shovel.

7. 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 angle of the dipper handle,

compare the angle of the dipper handle to one or more dipper handle angle limits,

determine a hoist bail pull,

compare the hoist bail pull to one or more hoist bail pull limits, and

set a crowd torque limit for the crowd motor drive based on the comparison of the angle of the dipper handle to the one or more dipper handle angle limits and the comparison of the hoist bail pull to the one or more hoist bail pull limits,

wherein setting the crowd torque limit includes setting the crowd torque limit to a first crowd torque limit when the hoist bail pull is less than or approximately equal to a first of the one or more hoist bail pull limits, and setting the crowd torque limit to a second crowd torque limit when the hoist bail pull is greater than the first of the one or more hoist bail pull limits.

8. The industrial machine of claim 6 , 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.

9. The industrial machine of claim 6 , wherein the second crowd torque limit is greater than the first crowd torque limit.

10. The industrial machine of claim 6 , wherein the industrial machine is a rope shovel.

11. A method of controlling a digging operation of an industrial machine, the method comprising:

determining a hoist bail pull associated with the industrial machine;

determining a crowd torque limit value for a crowd drive based on the determined hoist bail pull of the industrial machine; and

setting a crowd torque limit of the crowd drive to the crowd torque limit value to limit a torque associated with a crowding operation to the crowd torque limit value,

wherein determining a crowd torque limit includes comparing the determined hoist bail pull to one or more hoist bail pull limils, and

wherein setting the crowd torque limit includes setting the crowd torque limit to a first crowd torque limit when the determined hoist bail pull is less than or approximately equal to a first of the one or more hoist bail pull limits, and selling the crowd torque limit to a second crowd torque limit when the determined hoist bail pull is greater than the first of the one or more hoist bail pull limits.

12. The method of claim 11 , further comprising

determining an angle of a dipper handle; and

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

13. The method of claim 12 , 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.

14. The method of claim 11 , wherein the second crowd torque limit is greater than the first crowd torque limit.

15. The method of claim 11 , wherein the crowd torque limit is a function of the determined hoist bail pull.

16. The method of claim 15 , wherein the crowd torque limit increases as the determined hoist bail pull increases.