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Unread 17-04-2007, 22:28
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AKA: Ryan Newton
FRC #0418 (Purple Haze)
Team Role: Driver
 
Join Date: Feb 2005
Rookie Year: 2004
Location: Austin, Texas
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Re: Are two speed transmissions worth it?

Quote:
Originally Posted by Joel J. View Post
Something I'm curious to investigate is some sort of current-based shifting "algorithm." Have the drive default to a reasonable high gear (9-10 fps), then shift to low whenever the current draw grows beyond a certain value for a certain period of time. Then shift back to high when the current draw falls below a certain value for a certain length of time. Then have a manual override of some sort. Pretty much, the system only shifts to low to push.
We tried this but found that usually, if we were in 2nd gear and all of the sudden had a current spike, the motors were already close to stalling, or they were pulling so much current they would reset the RC. Well, in either of these cases the DeWalts we used weren't able to shift.
Basically, I'm sure it can be done, but keep in mind that the motors might not be turning when the robot is told to shift, so design your shifter accordingly.

As a driver, I think I liked the control over the system. 1st gear (5 ft/s) is painfully slow in a 2 min match, and getting pushed around is so frustrating you have to downshift.
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