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Unread 19-05-2010, 08:53
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VEX Robotics Engineer
AKA: Arthur Dutra IV; NERD #18
FRC #0148 (Robowranglers)
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Re: pic: Drivetrain Prototype

Quote:
Originally Posted by Mop Iii Top View Post
Hold the phone here. Why are you using 4 CIMs? I can see using 4 CIMs for Mecanum wheel, besides you have to use 1 CIM per mecanum wheel. This years limit on CIM Motors was only 5. You are using up most of them and not leaving yourself more for other things. If you used only 2 CIM Motors, one for each side, you would give yourself 3 CIM Motors to play around with on the rest of the robot.
Only using 2 CIM motors in a drive train will have a noticeable performance drop on regular carpet, as the robot will accelerate slower and in most cases will be torque limited (which means it'll lose almost every pushing match). Make Mark Leon happy and do the math. The numbers won't lie.

In 2009, the FRP flooring and acetal wheels had a much lower coefficient of friction, thus making a 2-CIM drivetrain not only feasible, but much better than a 4-CIM drivetrain at maximizing the potential use of each motor.

Edit: If you really want to have three CIMs for elsewhere on the robot, use CIM+FP combo for each gearbox. It'll provide better performance than a lone CIM would, and depending on how it's utilized (here's where math comes back in) might just very well be able to pull off a friction limited drivetrain, especially if it's use in conjunction with a shifting transmission.
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Art Dutra IV
Robotics Engineer, VEX Robotics, Inc., a subsidiary of Innovation First International (IFI)
Robowranglers Team 148 | GUS Robotics Team 228 (Alumni) | Rho Beta Epsilon (Alumni) | @arthurdutra

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Last edited by artdutra04 : 19-05-2010 at 08:59.
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